Abstracts for lectures and posters

This is the situation as of 20 July 1999. If you have sent your abstract to us by email, it should appear on this page. Tell us if it does not. The abstracts on this page may be shortened versions. Your full abstract will appear in the Conference Handbook (PDF format). Check also if we have received your printed paper.

No abstracts for lectures or posters will be accepted any more. Both the Proceedings and the Handbook have gone to print already.

If you have a web page with more info on your topic (perhaps your complete paper/poster), send us the URL and we'll include a link.

The abstracts have now been arranged in broader categories. If you feel that your presentation is completely in the wrong company, let us know.




Atomic/Subatomic physics

The use of X-ray Diffraction to investigate the structure of liquid matter - Modelling of the structure of concentrated aqueous solutions of indium bromide and lanthanum bromide Ana Margarida Medeiros Gaspar
X-ray diffraction is presented as a spectroscopic method used to investigate the structure of matter. Information that can be obtained from X-ray diffraction patterns is given. Modelling and Fourier inversion techniques as tools for interpreting the x-ray diffraction patterns of liquids are referred.

Application of this method to the study of concentrated aqueous solutions has revealed its usefulness to elucidate the plausibility of the existence of long-range correlations in these systems. The results obtained from the investigation of very concentrated aqueous solutions of indium and lanthanum salts are discussed.
* printed paper received: no

Determination of trace pollutants in water using photothermal laser spectroscopy George Ofori-Boadu
Pollution in water and other substances has been and is still a major concern for members of the global society. Some diseases have been incurred by people from drinking polluted water and eating food containing pollutants. Several experiments and methods have been performed and used to trace pollutants. We try to measure and monitor trace pollutants in water with high precision using photothermal laser spectroscopy.

Photothermal laser spectroscopy (PLS) has been applied to environmental monitoring and chemical analysis. Following a colorimetric reaction a pump beam is partially absorbed by a water sample, which results in a spatial modulation of the refractive index. The change in refractive index change is monitored by the deflection of a probe beam. Initial results on applying PLS to monitor trace amounts of pollutants (e.g. phosphate,iron, etc.) in water will be presented. In the future, we believe this method can be used in monitoring trace pollutants in water, crystals and gases.
* printed paper received: no

Elastic Peak Monitoring for the CLAS David C. Vermette
We have developed code to monitor one of the large, particle detectors (CLAS) at the Thomas Jefferson National Accelerator Facility (TJNAF). TJNAF is a large electron accelerator designed to elucidate the quark nature of matter. The software collects data generated from collision events in the spectrometer and periodically analyzes it. The elastic scattering peak in the $W$ spectrum is fitted to a Gaussian curve to measure its position and width. The position of the elastic peak is a measure of the accuracy of the detector calibration. The width of this peak is proportional to the resolution of the data.

The fit procedure is subjected to several tests to ensure quality. A minimum number of counts is required in the elastic peak region and the range of the values of the uncertainties is restricted. These results are stored in a database and can be viewed over the internet. We will present plots of the elastic peak data and related parameters to analyze how the detector's response can be monitored over time.
* printed paper received: yes

Nuclear level and state density Neven S. Fuckar
Experimental facts and qualitative conclusion that energy levels of heavy nucleus are very closely spaced and that their spacing decrease rapidly with increase of excitation energy required theoretical description even in the early days of development of nuclear physics. From the overall view nuclear level density is important ingredient in nuclear reaction calculation, particularly in heavy-ion reaction and nuclear astrophysics. More then 60 years ago Bethe realized that general behavior of the level density (number of nuclear levels per unit energy) would not on the average be significantly altered by the nuclear interaction and that nucleons in nucleus could be, for current purpose, viewed as a Fermi gas of free particles. Statistical method (or thermodynamic approach) used on stated model produced first theoretical expression for density of nuclear levels and states (number of nuclear states per unity energy) in dependence of energy for total magnitude and additionally in dependence of angular momentum for specific states. Further theoretical development within the limits of thermodynamic approach produced other formulas which can be adequately adjusted to the existing experimental data in certain energy range, like the constant temperature formula (CTF), or on entire spectrum, many others. In this work particularly is addressed the formula of Gilbert and Cameron (1965) as standard Bethe formula (SBF), which extends original Bethe formula to include the effects of paring and shell- correction energies introducing the energy shift. Following similar line of reasoning Paar and Pezer (1997) introduced generalized Bethe formula (GBF) which posses important capability of encompassing the SBF and the CTF as limiting case. Second different theoretical approach used in this work is combinatorial. It yields more exact results, but for extensive use it is very time demanding computational technique. Large scale combinatorial calculation of level densities based on realistic single particle spectra were performed for selected nuclei up to high excitation energy using Gaussian polynomial generating function method (GPM), new and efficient method introduced by Sunko (1990). Fitting of advance Bethe's formulas to the GPM results were analyzed in dependence of proton and neutron number. The best fitting was apparent for the GBF most evidently because of the well introduced second additional parameter. Many different lines of investigation were pursued on given calculations, e.g. how modification of single particle levels manifests in overall results - most important was variation in vicinity of Fermi energy, etc. Due to the obvious bounds imposed on lecture emphasis will be on basics of stated quantities and models, with selected results and general conclusions
* printed paper received: no

Breakup of 42 MeV $^7$Li projectile on $^{58}$Ni target Dhruba Gupta
Starting from a general description of direct and sequential breakup reactions, the measurement of 42 MeV $^7$Li-projectile breakup on $^{58}$Ni target is discussed. When the resulting fragments from breakup are detected at equal angles near the grazing angle, Coulomb breakup is seen to dominate, whereas outside the grazing angle when the fragments are detected at unequal angles , nuclear breakup dominates. Some indications of contributions from the higher sequential states (above 7/2$^-$ 4.63 MeV) of $^7$Li are found. Outside the grazing angle, direct breakup is reduced to a large extent compared to the sequential breakup. This aspect has important consequences for identifying unknown resonant states of the newly discovered halo nuclei.
* printed paper received: yes

Quality Control of GEMs Susete Teresa Gaspar do Fetal
The basic operation of gas detectors is described by atoms or molecules' ionisation, due to incident radiation. Gas mixture is enclosed within electrodes, which provide an electric field in order to separate and recovery electrons and ions. In high field regions, the electrons can be amplified in an avalanche process to produce a detectable charge signal. The microstructure based detectors (microstrip, microgap, GEM...) provide the electric fields required for multiplication charge. The results obtained with GEM (Gas Electron Multiplier) are very promising: amplification factor about several thousands, high count rate and spatial resolution better than 100 _m (RMS). Besides, GEMs are easy and low-cost to manufacture, so they are indicated for the new high luminosity colliders. The detectors will cover a large area (> 100 m2) and, due to technical constrains, will be assembled with small size elements (~ 20 X 30 cm2), thus a huge number of elements have to be manufactured. Quality control remains an important issue as, to avoid time consuming assembly and replacement, the defective units should be rejected immediately after manufacture.

Optical inspection is not acceptable because is slow (> 1 hour per piece), can not detect defects smaller than 5 _m and does not give direct information on the electric characteristics. The scintillation light, produced in GEM foils, when irradiated with x-ray, is observed with a CCD camera. Acquired images are a fast and non-destructive way to found defects in GEMs. In order to correlate defects, the images obtained with this technique were compared with images acquired with a microscope. Recently a new, small volume, big window camera was assembled. This system is controlled by two step-motors to sweep all the area and to improve a homogeneity study of GEMs.
* printed paper received: no

Statistical properties of the nucleus Amund Bjerve
In order to study hot nuclei with high internal energy, one can no longer perform classical spectroscopy since the spacings between the energylevels are much smaller than the experimental resolution. Instead, statistical models are applied to describe the nucleus under these conditions.\\ At Oslo Cyclotron Laboratory, University of Oslo, nuclei in the statistical regime are studied. The nuclear reactions used is $(^3{\rm He},\alpha )$ and $(^3{\rm He},^3{\rm He}')$ on rare earth nuclei $(A=140-190)$. This reaction leaves the nucleus with high internal energy and little collective motion such as rotation and vibration.\\ By using a subtractiontechnique, the first emitted gamma-quantas from each cascade are isolated from the rest. It is assumed that a so-called first-generationspectrum can be expressed as

\begin{equation} \Gamma(E_x,E_\gamma)=F(E_\gamma)\cdot \rho(U)\nonumber \end{equation}

where $\rho(U)$ is the leveldensity of the nucleus at the final energy $U=E_x-E_\gamma$, and $F(E_\gamma)$ is a function depending on the gammaenergy only. The leveldensity may be interpreted as the number of microstates, and by taking the logarithm one gets the entropy of the system.\\ As simple models for these two functions, a fermigasmodel is used for the leveldensity, and a giant dipole-resonance is used for the strengthfunction $F(E_\gamma)$.\\ A method has been developed for simultaneous extraction of the two functions, and the result can be compared to theory. Deviations from the pure statistical models may provide information about structures and non-statistical behaviour in the statistical regime.
* printed paper received: no

Teleportation in hole vacuum Constantin Leshan
Paper present the alternative method of teleportation that use hole technology. The ground station able to teleport macroscopic body as spacrsraft on the distance of millions light years in no time.
* printed paper received: no

Atomlasers Per Kangru
In the recent years there has been a great progress in the field of experimental lasercooling and Bose-Einstein condensation. This has lead to that we, during the last years, have seen some very intresting experiments regarding the subject of atomlasers. Atomlasers is a very new and fascinating field of quantumoptics. It has been foreseen by theory for many years but has been regarded as something purely theoretical, now once it has been achieved we are rapidly gaining knowledge about its inner workings.

I will discuss and present the most recent advances in the field and present some of the most interesting findings regarding atomlasers.
* printed paper received: no

Computational physics

Can Simulation Replace Nuclear Weapon Testing? Richard Williams
Sometimes setting up a research experiment can be too expensive or dangerous to be feasible. Is computer simulation a viable substitute for these experiments? This talk examines the current status of simulation physics through a case study of thermonuclear weapons. The thermonuclear device is dissected into the operational physics at work, including neutron transport, photon transport, hydrodynamic shock, and implosion fusion (among others). An overview of the problems that need to be solved is given and an estimate of the necessary computing power is made.
* printed paper received: yes

'Lyapunov Waves': Dynamical Instabilities in Hard Disk Systems in Equilibrium Robin Hirschl
The basic equations we use to calculate the time propagation of physical systems are linear. But the world we try to explain is mainly governed by nonlinear interactions. The resulting equations are extremely sensitive on initial conditions and lead to so-called deterministic chaos. Infinitesimally perturbed systems strive away from their reference system at an exponential rate. The rate of divergence in different directions of phase space is described by the Lyapunov spectrum. In computer simulations of hard disk systems we have discovered wave like disturbances that are very stable. Depending on the particles' direction of deflection the waves are stationary or propagate in a very distinct pattern through the system. The waves don't seem to be an artefact of the method but all attempts to link them to physical properties have failed untill now.
* printed paper received: yes

Radiosity: physical bases of this computer graphics method Michal Zielinski
Everybody realises that the computer graphics has a lot of applications in physics, especially in visualisation of various simulated processes, but only few understand how huge impact has physics on computer graphics methods. Mathematical and physical approach to computer graphics produces new efficient and giving realistic, visual effects methods. Beside ray tracing, which is now the most popular technique, a lot of new methods have been created. Radiosity is one of those techniques and it is strictly based on physics principles in a very large extent. The principle of conservation of energy, Southwell relaxation and photometry are necessary basics. Thus, physicists, thanks to their knowledge and mathematical workshop, have lots of possibilities in this domain of science.
* printed paper received: yes

Numerical weather forecasting Tomasz Sikora
The lecture presents ideas of numerical weather prediction. There will be presented steps of generating forecast: from meteorological measurements, through process of data assimilation, to visualisation of results. There will be discussed accuracy of traditional (synoptic) and numerical weather forecast. There will be presented methods of improvement forecast accuracy.
* printed paper received: no

Quantum physics

Loss of Coherence in Quantum Measurement Szabolcs Borsanyi
As it is well known, Copenhagen-interpretation of quantum mechanics does not yield a satisfactory explanation for the measurement theory. The idea of decoherence as a partial solution of the quantum measurement problem comes from E. Wigner. This theory describes the process, as the interference of quantum state is smeared, due to an interaction with the environment. It is pointed out, that the collapse of wave function (which is not to be mistaken for decoherence) is not assumed in our investigations. This lecture has the aim to demonstrate the environment induced decoherence. The presence and role of decoherence is shown on simple models. The general theory is also applied to some more realistic models that can be a basis of real measurement processes, such as particle detection. In our investigations a special attention is devoted to the temporal behaviour of decohering systems, i.e. we obtain estimates on the duration of measurement process.
* printed paper received: yes

Quantum Physics of Solar System Igor Kudrnovsky
Ever since the early civilization, people have viewed the universe and the solar system as being symmetrical and thus perfect, which was continued with Kepler's belief that a resonant structure created order in the solar system. Using simple classical laws of gravity it can be shown that the solar system might have a resonant structure, similar to those proposed by Rutherford and Bohr for the hydrogen atom. This lecture shall not go into those quantum principles, but will try to show that they are attainable.
* printed paper received: yes

Twin observables for mixed states Vladan Arsenijevic, Edib Dobardzic
From the very beginning of the modern quantum mechanics, the correlations of the subsystems composing the isolated quantum system have been attracting much attention. In fact, the description of the total system by its quantum state is essentially global, making the questions on the behavior of the subsystems much more subtle; the attempts to apply the classical intuition led to a number of paradoxes.

One of the problems frequently considered in this context is the possibility to perform the measurement of some of the subsystem observable, with the results being equivalent to measurement of some other observable of the remaining subsystem. This problem has been completely solved for the special case, when the total system, $\bS$, composed of the two subsystems, $\bA$ and $\bB$, is prepared into the pure state, $\ket{\Phi}$. Then, this state determines the mixed states of the subsystems, described by the statistical operators, $\rho_\bA=\Tr_\bB\ket{\Phi}\bra{\Phi}$ and $\rho_\bB=\Tr_\bA\ket{\Phi}\bra{\Phi}$. For each $\bA$-subsystem observable $A$, commuting with $\rho_\bA$, there is uniquely defined $\bB$-subsystem observable $B$, such that the measurement of $A\otimes I_\bB$ on the total system gives the same predictions as the measurement of the observable $I_\bA\otimes B$ ($B$ compatible with $\rho_\bB$), i. e.

\[\mbox A\otimes I_\bB\ket{\Phi}=I_\bA\otimes B\ket{\Phi}.\]

The aim of this paper is to generalize this result to the case of the mixed composite state, described by the statistical operator $\rho$. Such a generalization is interesting for the description of the complex systems, which can hardly be prepared into the pure state. For example, it may be important to know the properties of the electrons subsystem that can be determined by the measurement of some ionic observable in the thermalized solid, described by the canonical distribution.
* printed paper received: no

Materials physics/Applied physics

Lithography, an industrial application of physics Olav Frijns
As this conference will probably be filled with all kinds of very interesting lectures about research projects, I want to put a different accent: Is there physics outside university and research institutes ? The answer is yes, in some industries physics is a vital part of the business and it's no miracle that many graduated physicists end up in such places.

An example is the industry, which makes lithographic tools for microchip manufacturing. In the lecture I will show where physics comes into the lithography game and focus on the optical principles of micro-lithography including the relevant parameters and some numbers.

A short overview of the future of lithography will be presented with the theme "How low can we go ?" In this overview I will address some critical points, like the problems with optical materials, vibrations and optical designs. Finally I will devote a few words on how life of a physicist outside university can look like: what are the advantages and the disadvantages.
* printed paper received: no

TEM, HREM, SEM and X-ray diffraction study of iron doped TiO2 Igor Djerdj
Functional properties of TiO2-based ceramics can be improved by a small amount of doping. Improved photocatalytic efficiency of iron doped TiO2 has been attributed to the action of the iron ions within TiO2 matrix inhibiting photogenerated charge pair recombination. TiO2 was used in many applications such as integrated wave-guides and photovoltaic cells, gas and humidity sensors, inorganic membranes, catalyst supports and electrochemical displays.

In the present work, nanosized iron-doped TiO2 with Ti/Fe ratio=1:0.15 was synthesised by modified sol-gel method. Ti (IV) isopropoxide and iron (II) sulphate were dissolved in isopropoxide under inert (nitrogen) atmosphere and hydrolysed with PEG (polyethylene glycol) dissolved in doubly distilled water. PEG acts as a surfactant stabiliser, suppresses the coagulation, affects the pores and particle size distribution and improves homogeneity, microstructure and other properties of the final product. The suspension obtained after four hours of hydrolysis was dried and a resulting solid product was denoted as Sample 1. Sample 2 was obtained by, first, pressing of Sample 1 into the tablet and, then, by thermal treatment at 5000C for two hours. Samples were analysed by TEM, HREM, SEM, EDS and X-ray diffraction (XRD). High-resolution electron microscopy (HREM) was performed by using JEOL JEM 2010 200 kV microscope, having point resolution of 0.19 nm. SEM with energy dispersive X- ray analysis (EDS) was performed in JEOL-JSM-580 20 kV scanning microscope.
* printed paper received: no

Co-adsorption of CO and K on a stepped copper surface, Cu(115) Jakob B. Wagner
The coadsorption of potassium and carbon monoxide shows a different behaviour on the stepped copper surface Cu(115) compared to low-index copper surfaces, such as Cu(100) and Cu(110). CO on the clean Cu(115) looks very much like CO on the low-index surfaces, but when the alkali is added the CO will adsorb on the surface both molecular and, as a new phenomena, dissociative. This dissociation affects that carbonate is produced at the surface via the Boudouard reaction.

\par The stepped copper surface undergo a alkali induced reconstruction when a critical value of potassium coverage is passed. The reconstruction gives rise to steps twice as high and terraces twice as wide as for the original surface. This reconstruction is a possible condition for the dissociation of CO on the copper surface.
* printed paper received: yes

Determination of the surface structure of thin diblock copolymer films Trine H. Andersen
Diblock copolymers consist of two distinct polymers. We have studied poly(styrene) (PS) and poly(dimethylsiloxane) (PDMS) in an asymmetrical and in a symmetrical combination. In this lecture I will present results from the analysis of the asymmetrical combination. This diblock copolymer is 40.000 g/mol PS - 6.000 g/mol PDMS and is soluted in chloroform. Spin-coated films were annealed at 900C and 1300C corresponding to temperatures below and above the glass temperature of PS. The samples were studied with X-ray photoelectron spectroscopy (XPS). The surface segregation of PDMS was quantified by analysis of the XPS peak shape.
* printed paper received: yes

The Search for the Blue Laser Diode - Applications of GaN Semiconductors Nathan Langford
Blue LEDs and laser diodes have provided the technological world with one of the most dramatic advances of recent years, based on the use of gallium nitride (GaN). Yet, the resulting intensive research has not so far unlocked the secrets of this mysterious wide band gap semiconductor. During a summer vacation scholarship at the Australian National University, the photoluminescence properties of GaN related to defects introduced by ion implantation techniques were investigated using a broad band excitation spectrometer. This paper briefly outlines recent developments in GaN diode technology and describes the results of this particular study.
* printed paper received: yes

On the Magnetic Structure of Finite Multilayers Marton Major
The magnetic structure of Magnetic Multilayers (MMLs) exhibits rich and varied magnetic properties not found in bulk magnetic materials. Theoretical studies however often neglect the effects related to finite size effects.

A magnetic multilayer is a pile of magnetic layers separated by non magnetic ones. Different kind of phenomenological couplings can be observed in different systems. A bilinear antiferromagnetic coupling can occur in Fe/Cr multilayers. Understanding the behaviour of such a coupling is essential to go further in understanding the physics of giant magneto resistance (GMR) for example. The phenomenological model used widely in the literature consist of a few ``classical'' magnetic momenta (the objects of the model are the total magnetisations of the Fe layers) so it is not trivial, that you can neglect the effects coming from the \emph{finite} number of layers.

With the help of a flexible program it is easy to take into account the above mentioned finite-size effects. The first results are astonishing (collective mode for ex.). Some interesting 'movies' will be presented describing the behaviour of different multilayer systems.
* printed paper received: yes

Tracing the laser damage: Defect dynamics on the femtosecond time scale Janis Sils
Laser damage of transparent dielectrics has been an important area of studies for many years. Among the materials used in optical applications, several alkaline-earth fluoride crystals (CaF2, BaF2, LiF and MgF2) play a prominent role for handling UV laser radiation, where optical elements have to meet highest standards with respect to both, optical quality and damage resistivity.

Ablation thresholds and damage behaviour of the fluoride crystal surfaces produced by 248 nm/14ns laser pulses have been investigated in our previous studies giving us rather clear picture about the damage mechanism. The ablation was found to be dependent from the thermoelastic properties of particular material and was created mostly by absorption of the laser light and the following heating.

In our present studies the creation, separation and control of intrinsic lattice defects (F, H centers and self trapped exciton- STE) were examined by using femtosecond pulses in pump-probe mode. The sequence and kind of defect reactions was found to be dependent from electron-phonon coupling in each material. The possibility of laser controlled aggregation of defects and growth of metallic colloids in dielectric crystals, as well as the application possibilities of those were shown.
* printed paper received: no

The effect of the Sr-Ca titanate doping on phase formation and superconducting properties of BSCCO Marina Makarova
One of the ways to increase critical current density in high temperature superconductor is adding chemically compatible non-superconducting phase. The most effective is the small-sized particles addition. In this work the interactions between BSCCO superconductor and non-superconducting strontium-calcium titanates were studied.

Titanate powders of 20-25 nm particle size were obtained by oxalates thermal decomposition at 620C. They were added to the Bi-2223 superconductor, which was obtained earlier, and pressed into tablets. Also we studied doped samples of the same composition, but obtained from nitrate solution by its evaporation and thermal decomposition. The pressed tablets were sintered at 860C for 40 hours. Titanate lattice constants were calculated from Guinier diffraction pattern for all the samples: a= 0.3901 nm for strontium-calcium titanate and a= 0.3902 nm for strontium titanate, which is slightly less than for pure strontium titanate (0.3905 nm). Thus, strontium titanate with small (4%) amount of calcium is in chemical equilibrium with Bi-2223.

The XRD data show, that the quantity of the Bi-2223 phase is bigger in the samples prepared from titanate and superconductor precursors obtained separately. In the sample doped by calcium-strontium titanate we also have bigger quantity of the Bi-2223 phase. The critical temperature in doped samples is 2K lower than in the undoped. The obtained results confirm that SrTiO3 may be used as a pinning additive.
* printed paper received: yes, better version (by mail)

Study of tokamak plasmas by microwave reflectometry methods Tiago Tamissa Ribeiro
A brief introduction to nuclear fusion is made. The necessity of diagnosing the plasma in a tokamak reactor is stressed as result of the need of magnetic confinement and stability in a tokamak plasma. Microwave reflectometry is addressed as a powerful fusion plasma diagnostic. After analysing the methods to extract information from experimental data in fixed frequency operation, the results obtained from some ASDEX Upgrade discharges are discussed.
* printed paper received: yes

Making Stars in the Laboratory Heidi-Christina Bandulet
This serves as a brief outline of the basics of {\bf thermonuclear fusion} as the future's energy source. Discussed are elementary notions of {\bf plasmas physics, fusion by laser beams and ultraintense laser-matter interactions}. As an alternative to the classical scheme for laser fusion, the \textit{Fast Ignitor} scheme relies on the presence of a collimated beam of fast electrons that can propagate deep into solid matter. Our experiments at the Terawatt Laser of the LULI are of critical interest for this scheme. The interaction with fused silica targets produce such electrons whose propagation and spatial distribution are provided by optical probing. The gathered images presented here confirm our expectations and are promising for the realization of laser fusion in the future .
* printed paper received: yes

Polluting elements Mirco Coccoli, Alessandra Mussi
The group purpose was to measure nitrogen oxide and dioxide levels in the air of Milan. The period chosen is short (six days), however representative both of progress of a week and of pollution in Milan (obviously only referring to nitrogen oxides!). Using some devices, we have found what we attended: in the rush hours there is a peak in the graphic. On the contrary there is a hollow in the middle of the afternoon and a peak in the middle of the night. These facts are explained by the changes of thickness of the mixed stratus (the part of atmosphere in touch with the ground that is the part in which the dusts and the polluting elements are bound): as colder is the air, as thin is this stratus and vice versa. All this facts are clear from the graphic which represents the medium day. The graphic with the progress of all the recording days (March from the 3rd to the 9th ) shows another point of view: the difference between the various days of the week. In fact the working days are quite different from the week-end ones: the very high peaks are in the late afternoon of Friday and in the mornings of Saturday and Monday. This mean that in Milan many people arrive on Monday morning for professional purposes and leave for the week-end to stay with the family.
* printed paper received: yes

New compounds with interest in non-linear optics Francisco Villalobos Nascimento
Organic molecules with an extend (-electron shell and a conjugated donnor-acceptor group often have large polarizabilities and hiperpolarizabilities, exhibiting non-linear optical properties. A well-known example of such molecule is 4-Aminobenzophenone. When irradiated by LASER light, compounds based on this type of molecule show second harmonic generation, which has many technological applications in communications and optical data storage. In this work, new compounds with extended (-electron shells have been synthesised and their crystal and molecular structures characterised by X-ray diffraction. In addition, ab-initio calculations using extended basis-sets of the minimum molecular energy conformations and of the optical properties using time-dependent Hartree-Fock theory have been performed and shall be reported.
* printed paper received: no

Astronomy/Astrophysics/Space physics

CCD Astronomy: the electronic photography Ricardo Afonso, Emanuel Alexandre, Filipe Rosa Ferreira
Over the last decade, conventional photography was overtaken by a ³solid state sensor array² for astronomical imaging. The perpetrators of this revolution have been the CCDs (charged couple devices). There are four great advantages of the use of a CCD over conventional photography: a much greater efficiency; the response is linear, allowing direct measurements on the image; great amplitude of exposure time and extensive chromatic sensitivity. The most surprising fact regarding CCD is their high quantum efficiency that ranges from 60% to 70%, instead of 3% to 4% of prime-grade photographic emulsions. It happens that the price range of scientific CCDs is out of the possibilities of most common physics students. So they had to come up with a viable alternative that is the adaptation of a Quickcam or other similar low-cost CCD-based camera. This practice has spread within amateur astronomers that, with the help of convenient software and procedures, are able to achieve surprising results. In this lecture, we intend to present the results of some observation nights and explain the methodology for processing astronomical images emanated from a CCD (in our case, a B&W Quickcam).
* printed paper received: no

The U of A White Dwarf Home Page: Finding Charts,Positions and Other Information at the Click of a Button Peter Jensen
We have created a World-Wide Web site which conveniently collects finder charts and published data for a significant fraction of the White Dwarf stars in the McCook \& Sion White Dwarf Catalog. For each star, we display a finding chart, alternate designations, Hubble Space Telescope Guide Star Catalog coordinates and published photometric and astrometric data, with appropriate references. When available, we also include a listing from SIMBAD Astronomical database. We are in the process of completing this data set and hope to soon add additional information including photospheric and intersteller spectral line identifications, as well as optical, IUE, EUVE, ROSAT and similar spectra, with the assistance of our colleagues in the White Dwarf community. We also expect to soon augment this site with the capability to perform multi-field searches of the information in the database.
* printed paper received: no

Globular clusters in our galaxy Sinisa Prugovecki
Globular clusters are the most ancient objects in the Galaxy and we could say the most simple large-stellar-structures in Universe. So, from analyzing them, we can learn a lot, just like biologists learn about the whole life analyzing the most simple life-forms. With the development of technology we made very powerful telescopes that can observe globular clusters in other, far-away galaxies, but they can't observe single stars in each cluster. And if we want to compare those clusters with 'ours' we must study every Milky Way's globular cluster not as a bunch of stars, but as a single large object. In this lecture I will talk about those 'global' characteristics of globular clusters in Milky Way.
* printed paper received: no

Formation of the Solar System Bojan Pecnik
A brief overview of the Formation of the Solar System, and the planetary sytems in general, is given. Several models of formation will be shown, their physical mechanisms revealed and some points, which are still fairly poor understood, will be addressed. Lecture is concieved as an introduction to the problem of the Sol System Formation, with slides of the planets.
* printed paper received: yes

The Energetic and Relativistic Nuclei and Electron experiment ERNE Jarno Laivola
The Solar and Heliospheric Observatory (SoHO) is a joint space programs of the European Space Agency (ESA) and NASA for making the versatile lomg-term study on the Sun. One of the instruments on-board is the Energetic and Relativistic Nuclei and Electron experiment (ERNE) of University of Turku.

ERNE investigates the solar atmosphere by detecting charged particles produced in various energy release processes.The main target of ERNE is to undertake the first systematic survey of Solar Energetic Particles (SEP). Various properties - like elemental and isotopic abundance, temporal variations, anisotropy etc. - of solar-originated particle flux are detected. In the instrument there's two sensors: Low Energy Detector (LED) and High Energy Detector (HED). With these detectors it's possible to identify elements and isotopes from H to Fe in a wide energy range.

LED has an energy range of 1.3-13 MeV/n for H and He and 2.4-50 MeV/n for other nuclei. For HED the ranges are 11-120 MeV/n for H and He and 25-540 MeV/n for other nuclei. When there's no SEP production, ERNE observes galactic cosmic ray background from Milky Way.

SoHO was launched in December 1995 and it's been observing the Sun from a halo orbit around the L1 (Earth-Sun) Lagrangian point. The mission is expected to continue until 2003, which allows it to observe the solar activity maximum around mid-2000.
* printed paper received: no

X-Ray Observations of Microlensing Events Kjetil Kjernsmo
According to the General Theory of Relativity, light is deflected by gravity. In the case where a bright source is situated behind a massive object as seen from the observer, this may result in so-called \emph{Gravitational Lensing}. In the special case of strongly lensed quasars, two or more images of the same object may be seen. In addition, any clumping of mass in the lens, such as stars, MACHOs or star clusters will split the image into several micro-images. These cannot be resolved, but the bending of rays from such masses will focus or spread the light rays from the source, and thus change the brightness of the images over time due to the relative motion of the lens, source and observer. This is known as \emph{extragalactic microlensing}.

Microlensing may enable us to map mass distributions in very remote galaxies and can act as a powerful probe to quasar structure. Caustics are produced where light rays are focused on the observer, and High Amplification Events (HAE) are predicted to occur when such a caustic is crossed. Such an event has not yet been observed.

X-Rays are thought to originate dominantly from the innermost regions of quasars, from regions that may be as small as our solar system. If this is correct, HAEs may be observed in X-rays with the new observatories now being launched. If this happens, it may give us a lot of exciting new information and very good constraints on the important parameters: lens mass and source size.
* printed paper received: no

The Origin of Cosmic Rays - Galactic or Extragalactic? Davor Krajnovic
The origin of cosmic rays is still unknown and the cosmic ray spectrum doesn't show a natural end. There are ultrahigh-energy cosmic rays that enter the Earth's atmosphere carrying as much energy as a well-thrown rock. A straightforward question is: do the cosmic rays, which we observe locally, fill up only our Galaxy or do they fill up the entire Universe? There are several recent hypotheses that suggest that origin of cosmic rays may be galactic or/and extragalactic. The sources of cosmic rays might be: supernovas, galactic black hole accretion disks, gamma ray bursts and topological defects in the fabric of the Universe. Are they really straightforward answers?
* printed paper received: yes

Scintillation and refraction of stellar light during atmospheric occultations Veera Vainio
Stellar occultation is a method of measuring atmospheric constituents in the middle atmosphere. In stellar occultations the instrument measures stellar light throught the atmosphere, and the atmospheric constituents may be retrieved from the measured spectra by inversion techniques. During its travel throught the atmosphere the parallel ray bundle is strongly disturbed by the refractive effects of the Earth's atmosphere. There are basically three types of refractive effects: refractive dilution due to the atmospheric density gradient, scintillations due to density fluctuations and chromatic refraction due to the wavelenght-dependent refractive index of the atmosphere. In this paper we will present the physical principles of these effects, different theoretical models as well as balloon-borne measurement data on scintillation and refraction of stellar light.
* printed paper received: yes

Sunspots and the climate of the Earth Lauri Laakso
Galactic cosmic rays ionize air molecules in the atmosphere. These ions can facilitate vapours like sulphuric acid to nucleate to particles. Formed particles can grow further to cloud condensation nuclei, which may affect the cloud properties and cover. A model has been developed in aim to estimate if this route of particle formation is possible and if it is possible to verify it by measurements. Preliminary results show, that the verification is possible in tropospheric conditions during intensive particle formation.
* printed paper received: yes

Total Solar Eclipse of 1999 August 11 (Astronomical Expedition to the Total Solar Eclipse Path, Turkey'99) Sebastian Soberski
The expedition to the total solar eclipse path was organized by Grudziadz Astronomical Observatory.

Nearly four decades have passed since a total eclipse of the Sun was visible from Europe. The long drought finally ends with the last total eclipse of the Second Millennium on Wednesday, August 11, 1999. The path of totality begins as the Moon's umbral shadow touches down in the North Atlantic Ocean about 700 kilometers east of New York City.

First occurs after the shadow sweeps across the Atlantic and reaches England's southwestern coast. Cornwall and Devon lie in the path; Land's End stands on the centerline where the midmorning total eclipse lasts 2 minutes. Quickly traversing the English Channel, the umbra reaches the Continent along France's Normandy coast. The track runs through the French countryside where its southern limit passes just 30 km north of Paris. Residents of the City of Lights will enjoy a partial eclipse of 0.992 magnitude, in which 99.4 percent of the Sun's disk will be blocked. (Magnitude refers to the ratio of the overlapping solar and lunar diameters.) Continuing east through the Champagne region, the shadow swings across southern Belgium, Luxembourg, and Germany. Just north of the centerline, Stuttgart witnesses a total eclipse of 2 minutes 17 seconds. Munich's nearly two million citizens will also enjoy over 2 minutes of totality, provided skies are clear. As the eclipse path stretches through central Austria and Hungary, the umbra narrowly misses Vienna and Budapest, both of which experience partial eclipses of magnitude 0.99. As the shadow leaves Hungary, it briefly sweeps through northern Yugoslavia before continuing on to Romania. The instant of greatest eclipse occurs at 11:03:04 Universal Time in Romania's rolling countryside near Rimnicu-Vilcea. Here, the length of totality reaches its maximum duration of 2 minutes 23 seconds, the Sun's altitude is 59 deg., and the path is 112 km wide. Four minutes later, the umbra engulfs Bucharest, which stands squarely on the centerline. The shadow also enters northern Bulgaria before swinging out across the Black Sea.

The eclipse path reaches Turkey's northern coast and then continues southeast bisecting the country diagonally. Although Ankara lies 150 km south of the track it still experiences a deep partial eclipse of magnitude 0.967. The largest Turkish cities in the path of totality include Sivas, Elazig, and Diyarbakir.

The eclipse track begins to narrow and the duration drops as the shadow's trajectory takes it through Iraq and Iran. By the time the umbra enters southern Pakistan, central totality lasts less than 1.5 minutes. The five million residents of Karachi will experience a late afternoon total eclipse of 1 minute 13 seconds. Entering India, the track passes just south of Ahmadabad where a partial eclipse of magnitude 0.997 occurs. By the time the shadow traverses the Indian subcontinent, the duration falls below 1 minute and the eclipse occurs shortly before sunset. Sweeping out over the Bay of Bengal, the umbra leaves Earth's surface not to return until the next Millennium on June 21, 2001.
* printed paper received: no

Optics/Laser physics

Nonlinear optical and relaxation properties of thin fullerene-based films by modified time-resolved two-colour Z-scan technique: non-Gaussian laser beam approach Anastassia Gosteva
The work describes main principals of installation created to investigate third order nonlinear optical and relaxation film properties under picosecond laser excitation. The installation utilising combination of two different techniques: time-resolved longitudinal scanning and pump-probe method. The possibility to perform pump-probe experiment with different pump and probe beam wavelength allows reducing probe beam influence upon sample nonlinearity that was caused by pump beam irradiation. Experimental data analysis obtained by the two-colour time-resolved Z-scan was spread out into non-Gaussian laser beams. A number of comparative experiments on pulsed laser deposited (PLD) and thermal deposited fullerene films were performed. It was shown that despite of high stability of PLD films under laser irradiation their third order optical nonlinearity is much smaller than in thermal one.
* printed paper received: yes

Investigation of synchronously pumped KTP optical parametric generator Aleksandr Ovsianikov , Linas Urbonas
The work presents investigation results of the KTP OPO(second type phase-matching) synchronously pumped by CW Q-switched and mode locked ND:YAG laser SHG radiation. The pump laser generates 350 W power and 75 ps duration pulses. It was shown that the OPO with the fiber in the cavity must be used single mode fiber.
* printed paper received: no

Optical Tweezers: Non-Invasive Manipulation Cavin Talbot
Optical tweezers, which are becoming a powerful tool in a wide range of fields from biology to physics, use the optical gradient force from a sharply focussed laser beam to trap particles. Moving particles without physically touching them causes minimum damage and makes this a powerful experimental tool. The working principle behind optical tweezers is briefly explained and some uses described. The University of Queensland Physics Department has used optical tweezers to trap and rotate cogs, which may be the first step towards micromachines, and to manipulate chloroplasts in the study of plant cells.
* printed paper received: yes

Let there be light made by sound Emanuel Alexandre, Filipe Rosa Ferreira
Sonoluminescense means, quite simply, light from sound. The idea is very simple: a small bubble, surrounded by some liquid, is bombarded with sound. Due to the high energies now in the bubble, it starts to luminesce, or produce light. When researchers first discovered this phenomenon, they called it sonoluminescense. While sonoluminescense was first discovered in the 1930¹s, it received little attention until recently. In the past few years, a number of discoveries have been made, opening up even more mysteries. While most people have heard nothing about sonoluminescense, it has great potential in many scientific areas. High on the list for many researchers are its applications to fusion, since it is predicted that as sound bombards a bubble, the temperatures can get so hot as to allow fusion to occur within the bubble. Acordingly, there is some exciting research going on in this new field, and, according to Science, it is a remarkable laboratory for physics and chemistry.
* printed paper received: no

Photorefractive phenomena in waveguides Angel Mendez
Since its discovery in 1966 the photorefractive effect has been widely studied and many applications has appeared. On the other hand the great development of integrated optics has opened a new field for many nonlinear optical effects. Photorefractive phenomena began as a inconvenience but now better understanding and control of waveguides preparation procedures have made possible the use of photorefractive phenomena in practical applications. In this paper, after a theorical introduction, the photorefractive effect in {\f1 a}-phase proton exchanged LiNbO{\sub 3} waveguides is studied. A behavior very different to bulk samples is obtained. Some of the original results are: (a) Faster dark erasure kinetics and (b) Dependence of the saturation value of the diffraction efficiency with the recording intensity of light. These differences can be explained assuming the existence of other impurities, besides Fe as protons or shallow traps.
* printed paper received: yes

Geometrical Atom Optics: A Cold Atom Trampoline Carlos Saba
Using lasers it is now possible to cool clouds of atoms to temperatures of about a millionth of a degree above absolute zero. According to quantum mechanics atoms at such low temperatures increasingly take on ?strange? wave-like properties and behave less like particles. To study these properties we need to develop new techniques that allow us to manipulate cold atoms without heating them. We manipulate light waves everyday using mirrors and lenses and therefore atom-opticians aim to design analogous instruments to manipulate atom-waves, such as atom-mirrors and atom-lenses. Our group has been involved in the development of atom-mirrors. Several techniques exist for reflecting atoms using either laser light or static electric or magnetic fields, each having their own flaws and merits. Using commercial video-tape we have constructed the world?s first concave magnetic mirror. Below you can see an actual movie of a cloud of cold Rubidium atoms bouncing on this mirror and demonstrating the behaviour expected of atoms reflected from a high quality smooth concave surface. The ability to manipulate cold atoms to this degree of accuracy is important for any subsequent applications of laser cooling and atom-optics technologies. Atom optics is a burgeoning field and has a multitude of possible applications. These vary from the very applied such as the development of high precision gravimeters and the building of nano-structures to more fundamental physics challenges such as the possible construction of ``quantum computers''.
* printed paper received: yes

Theoretical/Mathematical physics

Motion of electron in magnetic field - problem of gauge and boundary conditions Pawel Wrobel
Motion of electron in magnetic field is a very well known problem. Everyone knows that clasically it is determined by Lorentz force. Quantum mechanically we start from a hamiltonian, which is gauge invariant. We can find energy levels (called Landau levels) and wave function for this problem using symmetric or Landau gauge. Solution cannot depend on gauge, however it is very difficult to see any similarity between solutions obtained in both gauges. Another problem we meet, when we consider limit of weak magnetic field. One easily find that for zero magnetic field all energy levels collaps to one level, whose energy is equal to zero and which has infinite degeneracy. Shortly - we do not get solution, which describes free electron motion (i.e. in crystal). In my lecture I will show a possible explanation for this problem.
* printed paper received: yes

Universality of late-time dynamics in nonlinear wave equations Nikodem Szpak
For linear wave equations ($\Box\phi+V \phi=0$), if $V$ has no bound states, $\phi=0$ is the global and stable atractor in time evolution. The late-time dynamics is dominated by so-called quasi-normal modes. Nonlinear wave equations ($\Box\phi+f(\phi)=0$), on the contrary, may possess some nontrivial ($\phi\neq 0$) stationary solutions, which in time evolution play the role of stable or metastable atractors. Metastable may be critical points between two scenarios of later dynamics. The dynamics near the atractors -- stable as well as critical points -- is universal (does not depend on the initial data) and is also dominated by quasinormal-modes.

Detecting of gravitational waves from creation of black holes is based on the observations of quasinormal oscillations of the gravitational field around the arising black hole.
* printed paper received: no

Contact: what is behind the Message? M. Luísa Arruda, Paula Stella Teixeira
In Carl Sagan's novel "Contact" we are introduced to the newly-born application of polarization modulation and to thoughts of interstellar travel through wormholes.

The Message consists of an encoded binary electromagnetic signal artificially created by an advanced civilization in Vega. The codification is achieved by asserting a bit 1 to a levopolarized portion of an electromagnetic wave and a bit 0 to the corresponding dextropolarized portion.

In this discussion we assume that the Message is sent to our home planet Earth through the same type of wormhole that is used by Dr. Eleanor Arroway and her team in their voyage to Vega. Wormholes are very tricky creatures; the first difficulty on this issue arises around their birth, which Sagan avoided by bringing into stage an infinitely advanced extinct civilization who built an entire network of interconnecting wormholes, (we will follow his example). The underlying properties of traversable wormholes will be discussed, such as exotic matter necessary to maintain the wormholes stability.
* printed paper received: no

Was Einstein wrong? Carlos A. Correa
The purpose of this paper is to present my point of view related to the constancy or not of the speed of light. The physics involved in relativity are not just considering light as a constant. The possible consequences of such description could lead to the understanding of other problems not yet known. Background radiation, may be much more than a lost explosion.
* printed paper received: yes

Introduction to Supersymmetry Marko Velic
Introduction. Weyl spinors and the two component notation. Supersymmetry transformation. Superspace and superfields. Chiral superfields and the toy model of spontaneous breakdown.
* printed paper received: no

Biological Evolution with Feedback Janos Asboth, Andras Vukics
We present a simple mathematical framework for the modeling of biological evolution with the state of the environment being affected by the strategies of the competiting species. So-called Evolutionary Singular Strategies can either be Evolutionary Stable or repellent, or they can be the source of speciation. Results in a one-dimensional strategy space are easy to understand. Multidimensional evolutionary dynamics can be more interesting: characterisation of Evolutionary Singular Strategies becomes difficult. This framework is applied to a specific model (Two-patch model) for the study of speciation.
* printed paper received: no

The Effective Adiabatic Approximation of Three-Body Problem with $\delta$-Potentials on a Line Denis Proskurin
The effective adiabatic approximation (EAA) of three-body problem on a line with short-range attractive $\delta$-potentials is constructed. The EAA lower bound for the energy with an absolute accuracy of order $10^{-6}$ is obtained. It is shown that EAA provides a true asymptotics of solutions and a correct behavior of the elastic scattering phase with an absolute accuracy of $10^{-3}$ in the interval $ 2 \ast 10^{-3} < q <\pi /6 $ of the relative momentum below the three-body threshold for (3 to 3) scattering. The convergence of adiabatic expansion using for construction of the effective long-range potential in the framework of EAA is demonstrated.
* printed paper received: yes, but unreadable (by fax)

Medical physics/Biophysics

CdTe nuclear stethoscope for cardiac gamma-ventriculography Youri Arntz
Two projects involving a pixellated conception of (-ray sensitive areas, based on arrays of semiconductor cadmium telluride (CdTe) detectors, have been developed for the assessment of cardiac performance in nuclear medicine. A gamma-camera project, developed in the frame of a European Community contract, is dedicated to imaging of the heart region on the non-moving patient. The camera head which has a 15 cm x 15 cm field of view, is transportable out of the nuclear department, for instance in intensive care units for emergency examinations. A nuclear stethoscope has also been developed as a hand-size probe allowing up to 33 data acquisitions per second, for beat to beat assessment of the left ventricle volume variations on the standing and exercising patient. The physical characteristics of the two systems are presented together with the first images obtained by the _-camera and results of preclinical investigations by the nuclear stethoscope.
* printed paper received: yes

Breathing physics Nuno Luis Barbosa Morais
Biomedical Physics is actually one of the most exciting research fields. Doctors and Physicists are now, more than ever, working together. You will get an overview of how this joint work can prevent you from being breathless...

There are some interesting physical aspects in Respiratory Physiology. Surface tension, gas laws and elastic forces are very important in the detailed study of the statics and dynamics of lung ventilation. Medicine is now using techniques based on physical concepts such as airways resistance or mechanical work to detect and fight against lung and respiratory diseases.

Today, simulations based on airflow models for the tracheobronchial tree are being made by some Biophysicists and their results fit experience quite well.

The nervous control of breathing is also an unexplored subject in which some experience in Physics may be useful...
* printed paper received: no

Measurement of object properties by Complex Interferometry OCT Maciej Wojtkowski
Optical coherence tomography (OCT) is a noninvasive imaging technique which provides microscopic tomographic sectioning of biological samples. This contribution presents a new OCT technique, which allows to detect the complex scattered field and compute the complex scattering potential of the object. The basic principle is outlined and experimental measurements in vitro and in vivo are shown.
* printed paper received: yes

Independent Component Analysis in functional Magnetic Resonance Imaging Andrzej Chojnowski
Recently Independent Component Analysis (ICA) has been introduced for functional Magnetic Resonance Images (fMRI) processing. The goal of that technique is to e a set of random variables as linear combinations of statistically independent components. In case of fMRI the random variables are images of brain activity sampled at a certain frequency. ICA tries to decompose them to component "maps" and their associated time courses. One assume that a single component map resembles a set of neurons involved with the same task and overall brain activity is simply a linear mixture of all cluster's activities. The data shown beneath come from a subject performing language comprehension test. One tries to compare ICA and tradtional, statistical analysis methods.
* printed paper received: yes

Raman and SERS studies on the new Ni(II) cupferronato complexes Ioana-Emilia Pavel
The ammonium salt of N-nitroso-N-phenyl-hydroxil-amine [PhN2O2]NH4 (cupferron) is a well-known analytical reagent. Additionally, the cupferron is a biologically active component, known to display carcinogenic, genotoxic and mutagenic DNA-damaging effect . In this respect, Raman and surface enhanced Raman scattering (SERS) spectra of the cupferron and new NiL2An, L=PhN2O2- , n=1, A=o-phenanthroline, o,o'-bipyridine and n=2, A=H2O, o-aminopyridine, o-diaminobenzene have been recorded for the first time and discussed. Vibrational analysis of the neutral ligand and new prepared Ni(II) cupferronato complexes suggests the electron delocalization through the coordinated ONNO unit and the coordination of the anionic ligand to the metal center through the oxygen atoms. The NiL2An complexes with n=1, A=o-phenanthroline, o,o' - bipyridine and n=2, A=H2O were found to adsorb on the Ag colloidal surface, suggesting a preference for the nanometer Ag colloid particles. The SERS bands associated to the chemical interaction between the ONNO unit and Ag colloidal particles were observed, indicating a parallel orientation of N-N bond with respect to the Ag particles. o-phenanthroline and o,o'-bipyridine ring vibrational modes behavior leads to a perpendicular orientation of the molecular structure of these compounds to the Ag surface. Raman fingerprint band of the new Ni(II) cupferronato complexes was found at about 1300 cm-1. SERS spectra of the title compounds bring additional arguments for the bidentate coordination of the ONNO group.
* printed paper received: no


Space-time Philosophy Sérgio Brissos, Bruno Ferreira
In this presentation we will study the indissociability of physics and philosophy, focusing our attention on the concept of space-time. The concept above mentioned is first tackled from the point of view of an individual who has no technical preparation in the modern theories of space-time, concepts such as the awareness of a geometry intrinsic to the universe will be discussed. We then move on to refer to the incorporation of the space-time concept in modern theories such as the theory of relativity and the quantum theory, always keeping in mind its philosophical implications. Finally we consider the path by which philosophical thought affects the creation and acceptance of a physical theory through the actions of a scientist, these ranging from religious and/or artistic to the proper context in which the scientist works.
* printed paper received: no

The Interrelationship of Science, Technology and Society Marc Meléndez Schofield
The purpose of this paper is to attract attention to the values which underlie certain advanced technologies and research projects, and which we tend to ignore. First, several examples demonstrate how technologies can be used for political ends. Then, we present some technologies which have a social impact which was not intended when they were designed. Lastly, we show how scientific research and theories also hide values which reflect the social context in which they were devised.
* printed paper received: yes


Physical chemistry

Comparative vibrational analysis of acridine derivatives in free state and adsorbed on Ag colloidal surface Adriana Manciulea
Vibrational Raman, IR and surface-enhanced Raman spectra (SERS) of 9-methyl acridine (9MA), 9-phenyl acridine (9PA), 9(10H) acridone (9A), and rivanol (2-ethoxy-6,9-aminoacridine-lactate) (RIV), have been recorded and analysed. Applications to trace assays of such pharmaceutical molecules have received keen interest because SERS holds considerable promise as a high sensitive analytical tool in medicine as well as in basic research of biological sciences [1, 2]. Large fluorescence [2, 3] is typically for visible excitation of these molecules. Therefor, near-infrared Fourier transform Raman or other techiques of quenching fluorescence were required. Totally missing of the fluorescence at very low concentration of sample is a proof that the SERS effect takes place and a preresonance or either resonance Raman contribution is supplementary added to the total enhancement of the signal.. Excellent SERS spectra of 9MA, 9PA, 9A and RIV were obtained. Many similarities of vibrational feature in the spectra allowd to conclude about the influence of the substituents on the vibrational behaviour of the acridine skeletal ring. Different SERS spectra of these molecule indicate a chemisorption of 9MA, 9PA and 9A and a physisorption of RIV respectively, on the Ag colloidal particles [4]. Vibrational assignments of the observed bands have been proposed. The most probable orientation of the studied molecules on the Ag surface was proposed.

Radiocarbon dating using accelerator mass spectrometry Sam Henry
Radiocarbon dating has been one of the most significant discoveries in 20th century science and is now an indispensable tool in archaeology, geology, environmental science and many other subjects. The age of an object is determined by measuring the amount of carbon-14 it contains. This can be done in two ways: by measuring the radioactivity of the sample; or by directly counting the number of carbon-14 atoms using accelerator mass spectrometry.

In ordinary mass spectrometry ions are accelerated into a magnetic field allowing particles of different masses to be separated. In order to detect carbon-14 atoms it is necessary to accelerate the ions to a high energy so that other mass 14 particles can be eliminated.

Electron transport in ammonia Nikola Paunkovic
Ammonia is one of the most important technical gases and is a frequent pollutant of the atmosphere. In literature there are very few papers on swarm parameters parameters in ammonia which makes it difficult to model a number of plasma applications that rely on e\bar{}-$NH_{3}$ cross section and transport data. Amongst the most important applications where such data are required are: flue gas removal, atmospheric modeling, plasma processing (T. Sommerer and M. J. Kushner, Appl. Phys. 71 (1992) 1654) for microelectronics and nitrading. It is therefore really surprising that in the literature a large discrepancies exist for the transport coefficients in ammonia (J. W. Gallagher, E.C. Beaty, J. Dutton and L.C.Pitchford, J. Phys. Chem. Ref. Data 12 (1983) 109). The most striking discrepancy is for the attachment probability (coefficient) where factor of 10 disagreement exists between the two available sets of data in the literature (J. W. Gallagher, E.C. Beaty, J. Dutton and L.C.Pitchford,J. Phys. Chem. Ref. Data 12 (1983) 109). Data for the cross sections obtained by beam methods are more abundant and should be used to provide transport coefficients for plasma modeling since there is a shortage of experimental transport data. In this paper we present the calculations of electron transport coefficients for ammonia based on electron scattering cross sections and attempt to resolve some of the discrepancies from the literature.

Theoretical/Mathematical physics

Thermodynamics in Special Relativity Carlos Russo, Gina Caetano, Nuno Santos
This issue was first investigated by Planck (1906) soon after Einstein's first results in 1905 on how mechanics and Newton's laws ought to be corrected. In the 1960s , Ott, Arzelies and Brotas reconsidered Planck-Einstein's theory and came to somewhat different conclusions, being the start of a new discussion.

However, discussions on how thermodynamics applies in special relativity hardly ever show up in books concerning either relativity or thermodynamics. This poster is designed to be regarded as a first approach into this subject, therefore exhaustive treatments are avoided.

It is shown how some quantities in thermodynamics change in a Lorentz transformation but special attention is given to pressure and heat.

Solitons in field theories Lisa Freyhult
In certain field theories there occurs stable finite energy solutions. These are called solitons. For certain Lagrangians it's possible to solve the equations of motion exactly or at least find some solutions. A few of these examples and some general properties of solitons will be discussed. If one could find solitons in some physical theory it would in principle be possible to find them in particleaccelerators. They would be seen as lumps of energy, looking very much as particles. Solitons come in different shapes, as infinitely long strings, pointlike, torusshaped or even knotlike objects. Magnetic monopoles are a type of solitons and a bit about these objects will also be discussed.

Descriptive Methods for the Examination of Wormholes and Black Holes Marcus Baumgartl
Starting from the simple Morris-Thorne-wormhole methods are motivated, which allow the description of highly generalized wormholes. This is done by the examination of null-foliations, which leads to the concept of marginal surfaces and trapping horizons. This terminology reveals a close relationship between black holes and wormholes, which even goes so far, that these two objects can be transformed into each other. Additionally the usage and meaning of Penrose diagrammes is explained and finally some special properties of wormholes are discussed briefly.

Biological Evolution with Feedback Janos Asboth, Andras Vukics
We present a simple mathematical framework for the modeling of biological evolution with the state of the environment being affected by the strategies of the competiting species. So-called Evolutionary Singular Strategies can either be Evolutionary Stable or repellent, or they can be the source of speciation. Results in a one-dimensional strategy space are easy to understand. Multidimensional evolutionary dynamics can be more interesting: characterisation of Evolutionary Singular Strategies becomes difficult. This framework is applied to a specific model (Two-patch model) for the study of speciation.

Experimental Tests on Relativity Carolina Alves, Luís Pedro, Verónica Malafaia
Description and analisys of a group of experiences which have allowed to test some aspects from Relativity (such as the Döppler effect, time dillatation, light deflection and the equivalence mass-energie). We have chosen the experiences which have a wider scope to the study of Relativity.

Medical physics/Biophysics

Analysis of human stabilogram data with statistical and chaos theory methods Janusz A. Urbanowicz
The poster presents application of various methods of data analysis - statistical (spectral analysis, probablility estimation, distribution reconstruction), and chaos theory based (reconstruction of attractor, estimation of fractal dimension and others) in analysis of medical measurements data. The data sets in question, are human stabliograms. Main purpose of the analysis is to produce diagnostic method based on human posturography. Some results are presented.

Independent Component Analysis in functional Magnetic Resonance Imaging Andrzej Chojnowski
Recently Independent Component Analysis (ICA) has been introduced for functional Magnetic Resonance Images (fMRI) processing. The goal of that technique is to e a set of random variables as linear combinations of statistically independent components. In case of fMRI the random variables are images of brain activity sampled at a certain frequency. ICA tries to decompose them to component "maps" and their associated time courses. One assume that a single component map resembles a set of neurons involved with the same task and overall brain activity is simply a linear mixture of all cluster's activities. The data shown beneath come from a subject performing language comprehension test. One tries to compare ICA and tradtional, statistical analysis methods.

The methods of nonlinear dynamics in the analysis of heart rate variability for children Maksim Säkki
The aim of the study was to clarify the applicability of the characteristics of nonlinear dynamics to the analysis of heart rate variability for children. We analysed the data collected from 24-hour ambulatory ECG monitoring under normal daily activities and their sleep-wake pattern. There was group of healthy children (12 subjects, mean age 11,5±3,3 years) and group of children with clinically documented sinus node disease (SND, 6 subjects, mean age 11,5±1,9 years). Besides, there was a heterogeneous group of 12 subjects with miscellaneous diagnosis. Holter tapes were analyzed using Marquette equipment with operating program Premier IV to obtain the time-domain and frequency-domain parameters of HRV.

The following characteristics were calculated:

- the standard "linear" characteristics, such as average NN-interval, SDNN, SDANN Index, SDNN Index, rMSSD, pnn50;

- the characteristics based on phase space, such as Shannon entropy based on "words" distribution; density distribution of points in the 3D, 4D and 8D phase space;

- the scale-invariant characteristics, such as fluctuation function, Hurst exponent; distribution for low variability regions based on Zipf's law.

In the case of healthy children and children with SND, there is no evidence of low-dimensional deterministic chaos in the time series of heart rate. For some patients, the structures in the phase space are apparent; however, they are to be attributed to a simple respiratory modulation of the heart rhythm. For the given group of patients, the scale-invariant methods are more appropriate tools. For healthy subjects, the time series reveals multiscaling behavior, whereas for patients with SND, the behavior is monoscaling.

We found that the logarithm of the peak density distribution of points in eight-dimensional phase space and the length of the longest low-variability region revealed significant variations over the patients. They were significantly correlated with the diagnosis (better than Shannon entropy and correlation dimension) and correlation with the other characteristics - such as SDNN, SDANN, pNN50 etc. - was remarkably low. All this suggests that these characteristics could serve as independent diagnostically useful parameters and can provide significant amount of additional information, not covered by the standard characteristics.

Functional Nuclear Magnetic Resonance in Imaging of Activity of Human Brain Piotr Tomczak
In the poster is presented the method of functional Nuclear Magnetic Resonance (fNMR) and its application to biological and medical researches especially to imaging of activity of human brain.

The Interaction of Ultra-Violet radiation with the Skin João Paula, Manuel Bettencourt, Rui Cardoso
During our live we are exposed to several kinds of radiation. We will talk about one of the most common kind of radiation that affects the human being, the Ultra-Violet, and focus mainly on his effects on the skin, where they are felt the most. We will approach this subject at a cellular level thus being able to establish the most relevant consequences of the interaction between UV rays and the skin.

Materials physics/Applied physics

PAC and its applications Beata Toczek
In a poster I give a brief description of the Perturbed Angular Correlation (PAC) technique and its application to the study of hyperfine interactions in solid state.

The researching method consists in introducing radioactive probes into given material. Thanks the decay of these isotopes in a compound we can measure angular correlations in gamma-gamma cascade and it let us come to conclusions about properties of this material. I would like to present results of my work using PAC spectroscopy to research materials containing isotope Lu(172).

Temperature dependence of the microhardness of polycrystalline C60 films Ilga Circene
Studies of temperature, light- and air- exposure effect on the physical, chemical and mechanical properties of fullerite C60 concerning the possible application of fullerite-based materials as a photorezist have attacted considerable attention. The aim of the present report was to investigate the temperature dependence of the Vickers microhardness of C60 films in the range of 300-680K. Fullerene films were prepared by thermal evaporation onto glass substrates at a pressure of 10(-4) Pa. The film thickness was 0.7..1 mu m. A nonmonotonous temperature dependence of the fullerite microhardness was found.

Both the temperature-induced softening on heating above 400-450K and oxidation- induced hardening on heating above 470K causes such behaviour. It was shown that the thermo-oxidation-induced hardness change is irreversible contrary the properties of photo-oxidised fullerite. It is in agreement with the fact that photo-oxidation alters the structure of fullerite leaving the fullerene cage intact while thermo-oxidation proceeds through the cage-opening reactions.

The surface structure in thin diblock copolymer films determined by XPS Trine H. Andersen
Diblock copolymers consist of two distinct polymers. We have studied poly(styrene) (PS) and poly(dimethylsiloxane) (PDMS) in an asymmetrical and in a symmetrical combination. The asymmetrical combination consists of 40.000 g/mol PS - 6.000 g/mol PDMS, where the symmetrical one consists of 25.000 g/mol PS - 25.000 g/mol PDMS. Spin-coated films were annealed at 900C and 1300C corresponding to temperatures below and above the glass temperature of PS. The samples were studied with X-ray photoelectron spectroscopy (XPS). The surface segregation of PDMS was quantified by analysis of the XPS peak shape. The surface morphology was determined as a function of annealing time. The two types of diblock copolymer-films form different structures.

Superconductivity Peter Ahrendt
An introduction to superconductivity. Quite short and very basic. Gives and outline of the development in the area of superconductivity, has information on possible applications using s.c. and try to set a goal for the future.

The effect of the Sr-Ca titanate doping on phase formation and superconducting properties of BSCCO Marina Makarova
One of the ways to increase critical current density in high temperature superconductor is adding chemically compatible non-superconducting phase. The most effective is the small-sized particles addition. In this work the interactions between BSCCO superconductor and non-superconducting strontium-calcium titanates were studied.

Titanate powders of 20-25 nm particle size were obtained by oxalates thermal decomposition at 620C. They were added to the Bi-2223 superconductor, which was obtained earlier, and pressed into tablets. Also we studied doped samples of the same composition, but obtained from nitrate solution by its evaporation and thermal decomposition. The pressed tablets were sintered at 860C for 40 hours. Titanate lattice constants were calculated from Guinier diffraction pattern for all the samples: a= 0.3901 nm for strontium-calcium titanate and a= 0.3902 nm for strontium titanate, which is slightly less than for pure strontium titanate (0.3905 nm). Thus, strontium titanate with small (4%) amount of calcium is in chemical equilibrium with Bi-2223.

The XRD data show, that the quantity of the Bi-2223 phase is bigger in the samples prepared from titanate and superconductor precursors obtained separately. In the sample doped by calcium-strontium titanate we also have bigger quantity of the Bi-2223 phase. The critical temperature in doped samples is 2K lower than in the undoped. The obtained results confirm that SrTiO3 may be used as a pinning additive.

Nuclear Fusion: the energy problem solution? Tiago Tamissa Ribeiro
Human energy needs and environmental damage already caused by the present day energy sources stress the need for new energy solutions. Nuclear fusion appears as a promising answer, not only because of its "clean" and "unending" nature, but also for its capability to satisfy the expectable human needs. The possible ways of building a nuclear reactor are presented. Radiation, radioactivity and risk assessment are also discussed.

Plasma kinetics of He2 molecules in fast discharges of high pressure helium Andrei Chizhik
In this work temporal emission and absorption characteristics of He2 dimers in high-pressure gas excited by a fast electrical discharge were investigated. The object of investigation is the discharge plasma in a commercially available miniature excimer laser PSX-100 (MPB Technologies Inc, Dorval, Canada). UV preionization and fast (10 ns) transversal pulsed discharge (maximum discharge current density of about 2 kA cm^(-2) and a pumping power density of about 20 MW cm^(-3)) were used for the excitation of helium gas. In order to minimize possible impurities in the helium gas (initial purity 99.99%), additional purification during the gas filling stage was performed by passing the gas through a zeolite trap immersed in liquid nitrogen. Time behavior of emission of the discharge in helium gas in 115-700 nm spectral range were investigated. Besides the well-known three body reaction of excited dimers creation:

He* + 2He -> He2* + He (1)

the reaction of direct electron excitation of dimers was taken into account:

He2(X 1(Sigma)g^+) + e -> He2* + e (2)

were He2 are quasibounded molecular pairs on the ground state. The density of these quasimolecules grows quadratically with pressure. The excitation of quasimolecules in the reaction (2) takes place in an initial stage of the discharge, while the formation of excited dimers by the reaction (1) occurs mainly on the late stages of the discharge. In the pure helium gas the He2 molecules play the role of additives, which have lower excitation (ionization) potential compared with the atomic helium.

The determination of gold from the alluvional sands trough the fast neutron activation analysis method Roxana Cristina Nat, Liviu Daraban
Besides a great number of chemical elements, the alluvial sands of the rivers consist of a large amount of gold with vary between 0-2500ppm. The unsteady distribution of the gold asks for great number of fast analyses for the dicovery of the samples which contain gold of a concentration greater than 30-40ppm, and which is justified in the exploitation.

The use of the fast neutron activation analysis comes up againest both lot of reaction interferences and instrumental interfeences.

Taking into account the great unsteady number of elements contained in the sand, the work studies these interferences and sets up the concrete conditions on which these interferences can be avoided so that the minimal, detectable gold value can be of 10ppm.

Spectroscopy of CsPbBr3 nanocrystals (quantum dots) in CsBr:Pb Natalja Zazubovich
Some years ago a new type of luminescent nano-crystals has been discovered: the CsPbX3-type aggregates created in CsX:Pb crystals (X=Cl, Br) by prolonged annealing at 150-250 oC [1, 2]. These crystals show very special luminescence properties caused by exciton quantum confinement effect due to very small (few nanometers) size of the aggregates (quantum dots) dispersed in CsX lattice. High efficiency, very fast (10-11-10-10s) decay kinetics of free exciton luminescence as well as high stability and simple preparation procedure of these nano-crystals may allow their applications in fast scintillators and solid state lasers.

In the present paper, absorption, emission and excitation spectra have been systematically studied at 4.2-300 K for CsPbBr3-type nano-crystals in as-grown and in annealed at various conditions CsBr:Pb samples with different lead concentrations (from 0.005 to 1.8 mole % of PbBr2 in the melt). It has been found that the intensity, positions of maximums and half-widths of the absorption and emission bands, the Stokes shifts as well as temperature behaviour of these characteristics depend on lead concentration and on the annealing temperature and duration. Polarisation of the free exciton luminescence of CsPbBr3 nano-crystals in CsBr:Pb caused by anisotropy of the nano-crystals has been observed for the first time, and the polarisation spectra, temperature and angle dependencies of the polarisation degree have been studied.

The conclusions have been made on the connection of optical characteristics of CsPbBr3 nano-crystals with their size and shape and on the orientation of anisotropic CsPbBr3 aggregates with respect to the CsBr crystal axes. The mechanism of the nano-crystals formation in the process of the thermally stimulated diffusion of Pb2+ ions in CsBr:Pb crystal lattice has been discussed.

Orientational Behaviour of Nematic Liquid Crystal under Oscillatory Flow Ildar Nasibullayev
Orientational dynamic of nematic liquid crystal layer with weak surface anchoring subjected to the oscillatory flow is studied theoretically. The nematic layer confined between two identical substrates that provide the weak planar or homeotropic anchoring is considered. For the case of oscillatory Couette flow when one of the substrates moves periodically along the direction within its plane and oscillatory Poiseuille flow when the time-periodic pressure gradient is applied in the direction within the layer plane, the director motion within the flow plane is analyzed.

The influence of the anchoring strength and surface viscosity on the director dynamics in the bulk of the layer and at the substrates is investigated in detail. The approximate analytical solutions of the nematodynamic equations for small flow amplitudes are obtained and compared with the results of full numerical simulations. The optical response of the nematic layer depending on the flow frequency, surface anchoring strength and surface viscosity is calculated.

The range of the flow frequency is found where the surface viscosity has the strong influence on the optical response and the experimental conditions that allow to estimate the surface viscosity more precisely are discussed.

Freedericksz Transition and Flexoelectric Effect in Nematic Liquid Crystal between Coaxial Cylinder Ilya Kotov
The orientational transitions in nematic liquid crystal confined between two infinite coaxial cylinders have been analyzed when the radial electric field is applied and flexoelectric effect taken into account. The problem with the director distribution ${\bf \hat n}=(n_r, n_{\phi}, n_z)$ depending only on the radius $r$ in the cylindrical coordinate system and strong boundary conditions has been studied. Two typical initial director distributions: planar orientation ${\bf \hat n}=(0, 1, 0)$ and homeotropic one ${\bf \hat n}=(1, 0, 0)$ are considered.

Since without an electric field the director distribution is deformed due to the confining cylinders, the orientational transition occur even in the absence of external field depending on the ratio of the radii of the inner cylinder to that of the outer one [1,2]. The Fr\'eedericksz transition in this geometry was analysed for the initial homeotropic orientation without flexoeffect [3].

Under an applied electric field one has the contribution of the flexoelectricity into the bulk free energy density in contrast to the case of plane nematic layer. The dependencies of the critical electric field for the Fr\'eedericksz transitions (nematics with dielectric anisotropy $\epsilon_a > 0$ and $\epsilon_a < 0$ for the planar and homeotropic boundary conditions, respectively) on the ratio of the outside radius and inside one have been calculated. It was found that for planar orientation the new type of orientational transition caused by the pure flexoelectric effects can take place. The polarity of critical field depends on the sign of flexo-coefficient that allows to determine the value and the sign flexo-coefficient in experiments. The influence of the flexoeffect in case of the weak surface anchoring is also analyzed.

Atomic/Subatomic physics

Investigation of Concentrated Aqueous Solutions by X-ray Diffraction Ana Margarida Medeiros Gaspar
What is X-ray diffraction? Which physical systems can be investigated by X-ray diffraction? Why to study aqueous solutions? How do ions and molecules are disposed in aqueous solutions?

Results obtained for some solutions are presented and compared with adequate and inadequate models.

Astronomy/Astrophysics/Space physics

Heating of the Galilean Moons of Jupiter by Tidal Forces Rene H. Larsen
I will give an overview of the calculations involved in approximating the amount of heat transferred to the Galilean Moons of Jupiter by tidal forces. This involves expressing the tidal potential in spherical harmonics and applying some results from the studies of elasticity in solids. By considering the displacement vector, and ultimately the strain tensor, for a component of the moon, I then obtain an expression for the amount of heat dissipated in the moon per second per volume element. Integrating this expression over the total volume of the moon and averaging over one orbit gives a fairly simple expression for the power of the heat dissipation in a Galilean Moon.

Finally, this theoretical result is compared with experimental data in order to determine if tidal heating is in fact the primary cause of the volcanic activity of Io, the innermost moon of Jupiter.

Chaos in the heaven Luis Contreras Sedes
One of the most firmly estaalished conceps of the Chaos theory is the famous butterfly effect:The genkle flapping of a butterfly`s wings in the tropics could be the origin of a tornado in Texas.Concretely,this reppresents the sensibility of certain system to initial conditions,as subtle variations can provoke unmense changes in the global results.This phenomenom appear in chemical process,stock exchanges,the weather...

Thus,a simple concept underlies the mecanism of very complex process.But what would happen if the chaos theory could explain the behavior of the appanently unchargealde extructure of the universe? Sometimes we continue to perceive the cosmos as something distant from the laws that govern the earth.Nothing fusther from the truth! the physical laws we observe here are equally valid in every corner of the universe.The heavens are not perfect in the way of Plato believed,but obey the laws of Chaos.

Microturbulences in the sun follw chaotic pathways.Even the orbits of planets can be described throught the KAM theorem according to which variations in the condictions can produce widely differnts effects.The strange attractors,key concept for the understanding of the implications of the Chaos theory,appear in astrofisical reseonch.These are mattematical entities whose simple formulation can originate in a fractal,infinitaly complex structure.A representative example is the large scale structure of the universe.Matter isn`t distributed homogeously but the galaxies tend towards certain points as atractors.

This poster presents several examples of the applications of Chaos theory of complex systems in astrophysics,such as the planetary orbits,solar turbulences and the structure of the galaxies. The realisations of the true size of the universe,of our situation in itand the laws that govern it is not justentertaiment for the astronomers,but leads to an advance in ourway of thinking,reminding us of our humility and at the same time giving importance to all small things we daily do and feel.

Stellar evolution M.Carmen Pereira Gonzalez, Dolores Salguero Gonzalez
We are going to describe a stellar model based on the Hertzsprung-Russel diagram.A star can be represented at only one epoch, for the continual emission of radiaton from the surface requires that some process be taking place within the star to supply the outflowing energy. Evolution is a consequence of the fact that a star is shining.We´ll trace the development of a star from the time it´s a dense cloud in the interstellar medium, through the pre-main- sequence, main-sequence and giant stages.

Neutrino Astrophysics Helle Kaasik
Neutrinos moving in the Universe carry information about events in their place of origin as does the light. Neutrinos are generated in stars in thermonuclear synthesis. Weakly interacting neutrinos easily penetrate all matter on their way. Outer layers of stars and atmosphere of Earth, even the Earth itself cannot disturb neutrino observations. The same reason makes neutrinos hard to detect, so neutrino telescopes are very large and expensive. They consist of large volume of water with thousands of photomultipliers. Photomultipliers detect the Cerenkov light cone from fast electrons and muons, which get their kinetic energy in interaction with a neutrino in the detector. The detected radiation enables to determine the flavour, energy and direction of the neutrino.

Solar neutrinos. Observed solar neutrino spectrum is suppressed and distorted when compared to calculated one. From two possible explanations for it - new physics for Sun or for neutrinos - now the second is indicated by results of the largest neutrino observation experiment, the SuperKamiokande. A model using neutrino vacuum oscillations gives a rather good agreement with solar neutrino spectrum observed by SuperKamiokande and also with results of earlier radiochemical experiments. The vacuum-oscillation model is indicating that the mass-squared difference of two neutrino mass eigenstates is 10 -10 to 10 -11 eV 2 with mixing parameter close to its maximal value. This result does not exclude possibility that a substantial amount of dark matter is neutrinos.

Aims and future of neutrino observations. Statistics and energy range of solar neutrino observations will increase. Neutrino telescopes can detect also supernova explosions. Observation of high-energy (E>TeV) neutrinos would allow deep observation of active galactic nuclei and would give important new knowledge about gamma bursts, ultra high energy cosmic radiation and (still hypothetical) weakly interacting massive particles. For this energy region of special interest for neutrino astrophysics 4 large projects for neutrino observation have been started: large water-Cerenkov detectors in natural water reservoirs. These projects have demonstrated and enhanced international co-operation among neutrino physicists.

Diffuse interstellar bands Karolina Darowny
The origin of diffuse interstellar bands (DIBs) is the longest standing unsolved problem facing astronomers who observe the spectra of early-type, bright stars. Near 300 absorption bands have been found in the ultraviolet, visible, and infrared regions of the spectra of stars obscured by interstellar gas and dust. Information allowing identification of the mysterious features may first of all come from four researches : 1. an analysis of DIBs' profiles, 2. correlations between DIBs' and interstellar molecules widths, 3. dependence of DIB strenght on color excess and characteristic features of interstellar extinction curve, 4. intercorrelations between DIBs.

The last one allows to form diffuse interstellar lines into groups, which are supposed to originate from the same carrier. The poster will contain results of intercorrelation between DIBs in the range from 470 nm to 560 nm and from 680 nm to 860 nm obtained by me.

Astronomical Observatory of Lisbon Ricardo Afonso, Susana Sousa
The poster has been set up with the intention of presentation the activities of the Astronomical Observatory of Lisbon as well as presenting information on its history and its importance. Due to the tight relationship that the observatory has with the university we will also introduce the Astronomy and Astrophysics Group of the Science Faculty of the University of Lisbon, their research programs, the resources available and international relationships.

Timing Neutron Stars (RT_4 - 32m. Radio Teleskop, Torun Radio Astronomy Obserwatory in Piwnice, Poland) Sebastian Soberski
Radio pulsars are rapidly spinning, highly magnetized neutron stars wchich emit beams of radio waves and are observed to pulse when the beam crosses the Earth. They represent the end-point in the evolution of massive stars, and are excellent labortories for the study of the bulk properties of matter at nuclear densities and beyond. Millisecond pulsars are old pulsars reborn through accretion of matter from a companion star, spinning so fast that the surface velocities approach the speed of light.

Pulsars are remarkable objects. In the quarter century since their discovery, they have had a impact on many fields of science. Understanding their composition is a challenge in nuclear and condensed-matter physics. Their elusive emission mechanism is a complex problem in electromagnetics, atomic physics and particle physics. Explaining their creation, evolution, and distribution is a classical astronomical task. The greatest contribution of pulsars observations, however, is their use as probes of other phenomena beyond pulsar physics. Pulsars provide great insight into the character of the interstellar medium. They provide fundamental beacons for astronometry, and they are also a most fertile ground for tests of general relativity.

The pulse trains emitted by pulsars are extremly stable, in at least one case comparable to the best terrestial atomic cloks: arrival times of pulses from PSR 1937+21 can be predicted with two microsecond accuracy over a time span of nearly a decade (Stinebring et al. 1990). Pulsar rotation behavior fits an extremly simple model: in all but the youngest pulsars, the rotation period is a slowly increasing linear function of time; these two quantities (period and period change over time) are free parameters in the timing model. Propagation across the 5000-light-second-radius orbit of the Earth significantly affects the pulse arrival times on Earth, in a manner wchich depends on the position of the pulsar in the sky. Thus the position of the pulsar, described by the two further parameters, must be included in the model. Finally the absolute arrival time of a pulse is arbitrary, adding a fifth parameter. Many facts about pulsars emerge from this five-parameter model.

In Torun Radio Observatory there are two radiotelescops: 32 m. RT-4 parabolic radio telescop with a horizontal stand and 15 m. RT-3 parabolic radio telescope (paralactic stand). Near 100 pulsars are frequently observed (1700 MHz). For this purpose is used pulsar machine called PSPM2 (Pen State Pulsar Machine 2). In this poster I am going to present the resultss of pulsar timing programme.

Weather and climate of Polish mountains Tomasz Sikora
The poster presents weather and climate conditions of Carpathians and Sudety Mountains. There will be presented data concerning cloudiness, precipitation, temperature, winds and other elements of weather and climate. There will be presented possible methods of numerical simulations of atmospheric air flows over mountain terrain.

Artificial intelligence

Chaos theory and the neural networks Dubravko Kicic
Relatively new development in computer science is field of neural networks (or so-called atrificial neural networks). Development of neural networks was in teens in the 1960s, but recovered for reinassance in 1980s. Chaos is a new mathematical theory, dating back to perhaps the 1960s at the earliest and blooming only in the 1980s. The intersection of chaos theory and neurobiology has happened intensively back in perhaps ten years. The use of chaos theory in the development and study of artifical neural systems (a.k.a. neural networks) is newer still.

Artificial intellect Sandijs Jercums
Artificial intellect is one of the most newest branches of science and is currently considered to be the fundament of programming in future. As a subject of computer science it studies a way to make machines to do such tasks, the performance of which would need as much intelligence as for the human being.

There are two dominant directions of artificial intellect: bionics and applied programming. The first direction investigates the functioning and structure of human brain from the neurophysiological and psychological point of view. The direction of applied programming investigates the way of making programmes, which would be able to solve the problems used to be solved only by the human being itself (including the creation of such programmes). There are variety of applications of this direction of artificial intellect in practically every field of human activities, covering also technical and scientific areas. From the applications in physics, recognition of the structure of molecule from it's spectroscopy data, object recognition and imaging in the navigation can be mentioned. Important feature of the artificial intellect is the capability to handle incomplete information about the system and offer solution possibilities for the people to choose.

In present studies several applications and principles of functioning of the artificial intellect, as well as it's future challenges are discussed.

Optics/Laser physics

Nonlinear cross talk in photorefractive recording of multiple holograms Josefa Limeres, Mercedes Carrascosa
The photorefractive (PR) effect [1] consists in a change of the refractive index induced in a photoconductor, electrooptic material under inhomogeneous illumination. The physical mechanism underlying the PR effect involves photoexcitation of charge carriers from impurity levels, migration of the carriers by different mechanisms (diffusion, drift, ...) and eventual recombination at trap sites. The consequent non-uniform redistribution of charge gives rise to a space-charge electric field. In turn, a refractive index modulation is induced via the electrooptic effect. Then, a phase hologram -replica of the original light pattern- is recorded in the PR medium. The most interesting features exhibited by PR materials are their high sensitivity and the possibility of either storing information for long periods, either erasing and reconfiguring the recorded holograms.

Most proposals of applications of the PR effect -holographic storage, optical interconnects, real-time holography or optical processing [1]- involve the simultaneous presence of several holograms within the same volume. When more than one hologram are recorded in a PR material, the generation of each hologram is not independent of the others. On the contrary, they are coupled through the intrinsic nonlinearity of the processes involved in the PR effect. As a consequence, the strength of the holograms can be strongly affected (the so-called nonlinear grating cross talk) [2,3]. Also, new spatial frequencies -absent in the original light pattern- may appear in the final recorded hologram (spatial frequency mixing) [4]. In our poster, we will show several examples illustrating the importance of these kind of effects in PR experiments.

First, we will describe the theoretical formulation explaining the appearance of nonlinear effects in multiple grating recording [2,3]. The main features and the parameters governing the strength of the nonlinear effects will be discussed on the basis of the model. Next, the theoretical results will be compared with available experimental data in different experimental situations.

Finally, we will analyze the most important consequences of the nonlinear grating cross talk and its implications with regard to PR applications such as holographic memories or optical interconnections.

The Cr3+ photoluminescence in ZnAl2-xCrxS4 spinel Alexei Nateprov
The Cr 3+ photoluminescence has been measured in the crystals of _-spinels ZnAl2-xCrx at temperatures 77 and 300 K. The crystals were grown by a closed tube vapor method with AlCl3 as a transport agent. The Cr3+ ions concentration was estimated from magnetic susceptibility measurements. Photoluminescence spectra were excited using radiation at 633 nm from He-Ne laser. Well known R-line (_max=771 nm, 2Eg - 4A2g emission transition) and its vibronic sideband predominated in the emission spectrum in samples with low Cr concentrations (x<0.02). As the Cr concentration is increased the R-line and its vibronic sideband become less intense and disappeared. Two new wide bands of luminescence with _max=845 nm and _max=935 nm appeared in the emission spectrum when Cr concentration still more then 1% (x>0.02). The first one is result of increasing broad-band 4T2g - 4A2g fluorescence and estimation of gap between 2Eg and 4T2g gave _=0.26 eV. The origin of band with _max=935 nm is not so clear. Probably that it is a result of influences of exchange interaction between ions of the Cr3+ on luminescence, as intensity this band increasing both at downturn of temperature and with increase of Cr concentration. For samples with x=0.28 only one band with _max=935 nm exist in the emission spectrum at all temperatures.

"Small Star"-sonoluminesence Jacek Madry
A single gas bubble trapped in a standing-wave sound field can emit pulses of blue-white light whit duration less than 50 ps. The spectrum of the light flashed out once every acoustic cycle from their bubbles spans the whole visible spectrum, form red to blue, and then extend into the ultraviolet as far as the frequency at which water becomes an efficient absorber of radiation. Measurements of the spectrum are report for air bubbles levitated in water. Not everything yet understood.

Direct numerical treatment of the nonlinear light wave in the optical fiber when phonons are present Olja Jotanovic, Snjezana Popovic, Aleksandra Andjic, Lidija Milutinovic
The propagation of nonlinear light wave in an optical fiber when phonons are present is described by the modified nonlinear Schroedinger equation. Direct numerical solutions of this equation have been obtained using the Runge-Kutta method. We have computed with different values of the phonon frequency and the intensity of photon-phonon interaction. Phase diagrams of regular and chaotical solutions are obtained. It is investigated conditions for the transition from regular to chaotical behavior.

Quantum physics

Quantum Computation Slawomir Soszynski, Ryszard Jabczynski
This presentation is in three parts: introduction to quantum computing, a specification of logic gate and a mathematical representation as well as a theoretical design of a quantum computer.

The quantum model of computation is a probabilistic model, similar to the probabilistic Turing Machine, in which the laws of chance are those obeyed by particles on a quantum mechanical scale, rather than the rules familiar to us from the macroscopic world.


Physics in the German-speaking literature Barbara Feher
I would like to give you with my poster some ideas about the responsibilty of Physicists. I ask couple of well-known representatives of the German-speaking literature for advice: Durrenmatt, Brecht and Christa Wolf. Durrenmatt is a Swiss playwright and novelist, whose work has affinities with black humor and the theater of the absurd. I examine the message of "The Physicists" (Die Physiker), a modern morality play about science, which is generally considered his best play. Brecht was the most important German playwright of the century. I draw conclusions from his "The Life of Galileo" (Leben des Galilei). I finish with the novel of Christa Wolf: "Malfunction" (Storfall - Nachrichten eines Tages). She writes about the reaction of the laity after receiving the news of the catastophe in Chernobyl.

Nexus - the network of student physicists Julia Rose
Nexus is the network of student physicists and Physics Societies in the United Kingdom. As a part of the Institute of Physics, members get all the opportunities the Institute offers but also a range of special activities only for students.

Nexus students all receive a termly magazine and have their own website. Through Nexus students have participated in a range of activities from paintballing to visiting CERN, football matches to watching the eclipse this summer! Crossing the boundaries between Universities allows students the opportunity to make valuable new contacts and compare experiences, as well as passing on information and tips such as how to find the best work placements.

Physics relation to Psychology Patricia Lourenço, Manuel Bettencourt
R. P. Feynman wrote 'if our small minds, for some convenience, divide this glass of wine, this universe, into parts ­ physics, biology, astronomy, psychology, and so on ­ remember that nature does not know it!'. From a general point of view, this lecture weakens the gap between sciences historically known as natural and social. We will begin by explaining the applications of theoretical physics on psychological theories. On a second part we visit achievements on technological physics and point out their implications on the construction of cognition psychology and others psychological fields.

''It's like that !! And that's the way it is'' Run D.M.C. vs. Jason Nevins César Marques, Sónia Arroz, Catarina Casteleiro
The Physic's thought, Math as a Physic's tool or Physic's as a Math's tool, Big Bang is wrong ?, creation or occupation, speed's limit, are we special? and something else to think about.