An algebraic approach to Wigner's unitary-antiunitary theorem

We present an operator algebraic approach to Wigner's unitary-antiunitary theorem using some classical results from ring theory. To show how effective this approach is, we prove a generalization of this celebrated theorem for Hilbert modules over matrix algebras. We also present a Wigner-type result for maps on prime C*-algebras.Comment: AMSLaTeX, 17 pages. To appear in J. Austral. Math. So

Use of Policy Risk Assessment Results in Political Decision Making

The RAPID project established, during the first period, a thematic network of risk assessment experts, including relevant partners in the ten countries involved, the "Risk assessor database". The project devoted a specific activity, a single work package, to the dissemination and discussion of the methodology developed during" first two years of the project. National workshops were planned in each country to facilitate integrated knowledge translation activity, using a participatory approach to increase potential knowledge-users awareness on the RAPID project, and to engage them in using the RAPID guidance. Workshops were conceived to present case studies and the RAPID guidance to a targeted audience, to discuss and collect further insights, and integrate different perspectives in the final version of the policy evaluation methodology. However, national workshops also actively contributed to develop evidence based methodological guidance and increase its quality and relevance for potential users by bridging know-do gap between researchers and stakeholders; by involving decision makers and potential users in the knowledge creation process; by facilitating diverse stakeholder participation from governmental, academic and private sectors, carefully identified by national RAPID surveys as having direct expertise in the field of risk assessment. The cultural and administrative differences existing in the countries involved in RAPID guarantee the inclusion of a wide range of perspectives. Results of the national workshops helped to identify barriers and solutions for using the guidance, for adapting necessary changes to it and for communicating results to other potential users.

Public Health, Policy Analysis, Risk Assessment,and Impact Assessment

Public health has been defined as "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals"(Winslow 1920) or as "the art of applying science in the context of politics so as to reduce inequalities in health while ensuring the best health for the greatest number"(WHO1998). As the challenges of public health have evolved, from sanitary surveillance and infectious diseases in the past, to chronic diseases, lifestyle factors,socioeconomic conditions, occupational and environmental health determinants,health reforms and others, so have the methods of assessment advanced by research technologies development. The new health threats and epidemics, such as AIDS, SARS (Severe Acute Respiratory Syndrome), influenza H5N1, or emergencies like natural disasters or bioterrorism, effects of globalization and migration present new tasks to public health governance requiring new working methods.

The Konkoly Blazhko Survey: Is light-curve modulation a common property of RRab stars?

A systematic survey to establish the true incidence rate of the Blazhko modulation among short-period, fundamental-mode, Galactic field RR Lyrae stars has been accomplished. The Konkoly Blazhko Survey (KBS) was initiated in 2004. Since then more than 750 nights of observation have been devoted to this project. A sample of 30 RRab stars was extensively observed, and light-curve modulation was detected in 14 cases. The 47% occurrence rate of the modulation is much larger than any previous estimate. The significant increase of the detected incidence rate is mostly due to the discovery of small-amplitude modulation. Half of the Blazhko variables in our sample show modulation with so small amplitude that definitely have been missed in the previous surveys. We have found that the modulation can be very unstable in some cases, e.g. RY Com showed regular modulation only during one part of the observations while during two seasons it had stable light curve with abrupt, small changes in the pulsation amplitude. This type of light-curve variability is also hard to detect in other Survey's data. The larger frequency of the light-curve modulation of RRab stars makes it even more important to find the still lacking explanation of the Blazhko phenomenon. The validity of the [Fe/H](P,phi_{31}) relation using the mean light curves of Blazhko variables is checked in our sample. We have found that the formula gives accurate result for small-modulation-amplitude Blazhko stars, and this is also the case for large-modulation-amplitude stars if the light curve has complete phase coverage. However, if the data of large-modulation-amplitude Blazhko stars are not extended enough (e.g. < 500 data points from < 15 nights), the formula may give false result due to the distorted shape of the mean light curve used.Comment: Accepted for publication in MNRAS, 14 pages, 7 Figure

Lambda production in central Pb+Pb collisions at CERN-SPS energies

In this paper we present recent results from the NA49 experiment for $\Lambda$ and $\bar{\Lambda}$ hyperons produced in central Pb+Pb collisions at 40, 80 and 158 A$\cdot$GeV. Transverse mass spectra and rapidity distributions for $\Lambda$ are shown for all three energies. The shape of the rapidity distribution becomes flatter with increasing beam energy. The multiplicities at mid-rapidity as well as the total yields are studied as a function of collision energy including AGS measurements. The ratio $\Lambda/\pi$ at mid-rapidity and in 4$\pi$ has a maximum around 40 A$\cdot$GeV. In addition, $\bar{\Lambda}$ rapidity distributions have been measured at 40 and 80 A$\cdot$GeV, which allows to study the $\bar{\Lambda}$/$\Lambda$ ratio.Comment: SQM proceedings. J. Phys. G: Nucl. Part. Phys.: submitte

Preliminary geochemical characterization of gas manifestations in North Macedonia

L ike most of the Balkan Peninsula, North Macedonia is a geodynamically active area. As such it has many hydrothermal features and gas manifestations. Until now, no systematic study about the geochemical characterization of the geogenic gases was made before in this country. In August 2019, 24 gas samples were collected in the study area. All, except one collected at Duvalo (soil gas), are gases bubbling or dissolved in thermomineral waters (temperatures from 12 to 66 \ub0C). They were analysed in the laboratory for their chemical (He, Ne, Ar, O2 , N2 , H2 , H2S, CH4 and CO2) and isotopic composition (\u3b413C-CO2, \u3b413C-CH4, \u3b42H-CH4 and R/RA). Most of the gases have CO2 as the main component (400-998,000 ppm) while the remaining are enriched in N2 (1300-950,000 ppm). Helium ranges from 0.3 to 2560 ppm while CH4 from 1.6 to 20,200 ppm. R/RA and 4He/20Ne ratios indicate a generally low atmospheric contamination, a prevailing crustal contribution and mantle contributions between 1 and 20% considering a MORB endmember. The highest mantle contributions are found in the SE part of the country very close to the sites that show the highest R/RA values in continental Greece [1]. This area is characterised by extensional tectonics and Plio- Pleistocene volcanism. A quite high mantle contribution (about 15%) is also found in two manifestations in the NW part of the country along a main normal fault system. With the exception of the sample of Smokvica, which has very low CO2 (1400 ppm) and \u3b413C-CO2 (-15.7 \u2030 V-PDB), all free gases show a relatively narrow range in \u3b413C-CO2 values (-4.6 to +1.0 \u2030 V-PDB) indicating the mixing between a mantle and a carbonate rock source. The isotope composition allows us to assign the CH4 origin to three sources. The largest group can be attributed to a hydrothermal origin (\u3b413C-CH4 around -20 \u2030 V-PDB and \u3b42H-CH4 around -100\u2030). Three samples collected in the SW part of the country have a thermogenic origin (\u3b413C-CH4 around -35 \u2030 V-PDB and \u3b42H-CH4 around -160\u2030 V-SMOW). Finally, one sample (Smokvica) with the highest values (\u3b413C-CH4 -7.2 \u2030 V-PDB and \u3b42H-CH4 -80\u2030 V-SMOW) may be attributed to abiotic processes in a continental serpentinization environment or to methane oxidation

Macroparasite dynamics of migratory host populations

Spatial variability in host density is a key factor affecting disease dynamics of wildlife, and yet there are few spatially explicit models of host-macroparasite dynamics. This limits our understanding of parasitism in migratory hosts, whose densities change considerably in both space and time. In this paper, we develop a model for host-macroparasite dynamics that considers the directional movement of host populations and their associated parasites. We include spatiotemporal changes in the mean and variance in parasite burden per host, as well as parasite-mediated host mortality and parasite-mediated migratory ability. Reduced migratory ability with increasing parasitism results in heavily infested hosts halting their migration, and higher parasite burdens in stationary hosts than in moving hosts. Simulations reveal the potential for positive feedbacks between parasite-reduced migratory ability and increasing parasite burdens at infection hotspots, such as stopover sites, that may lead to parasite-induced migratory stalling. This framework could help understand how global change might influence wildlife disease via changes to migratory patterns and parasite demographic rates

Of Mice and Men, and Chandeliers

How does the human neocortex reliably propagate information through neural circuits? One mechanism appears to involve relying on strong connections from pyramidal neurons to interneurons and a depolarizing action of cortical chandelier cells