Macromolecular organic acids in the Murchison meteorite

This study has detected bound organic acids within the Murchison meteorite organic macromolecule. Benzoic acid was the most abundant compound; other abundant compounds include C1 and C2 benzoic acids. Their origin and significance will be discussed

Factors Affecting Efficiency Of Railways In Terms Of Safety At Railway Level Crossings

Road traffic accidents are in the top ten of all deaths, with around 1.4 million fatalities and 50 million injuries per year worldwide. Regarding railways, in the EU there were 1666 serious accidents registered in 2018 and 442 of them involved Level Crossings (LCs). The number of accidents on level crossings in the EU in 2018 was approximately 27% of the total number of accidents on railways, but these accidents can be predictable and preventable. The current study investigated the efficiency of railways in terms of accident risk at LCs in 24 countries of the EU. The Data Envelopment Analysis (DEA) method has been applied to evaluate the efficiency of selected railways in terms of safety at LCs. After extensive study of the subject, the comprehensive list of influencing factors has been identified and seven of them have been selected for further analysis. To investigate the relationship between selected factors and efficiency score of railways in terms of accident risk at LCs, the IBM SPSS software package has been deployed. The results show that GDP per capita and density of population in the selected countries have a strong influence on the efficiency of railways in terms of safety at LCs. The expected outcome of this research may contribute to a better understanding of the factors that influence the efficiency score of railways in term of accident risk at LCs and may help to develop preventative measures

Investigation of Factors Influencing the Efficiency of railways in Terms of safety at Level Crossings

ABSTRACT Road traffic accidents are in the top ten of all deaths worldwide. Regarding railways, in the EU there is one person killed or seriously injured every day in serious accidents involving level crossings (LCs). The number of accidents is almost unchanged in the last ten years despite the huge efforts that railways have made. There is a need to look at the factors that contributed to the occurrence of accidents at LCs beyond the drivers and pedestrian behavior or technical issues. The reported research investigates the efficiency of railways in terms of accident risk at LCs in 24 countries of the EU. It evaluates the efficiency of railways by applying the Data Envelopment Analysis (DEA) method and identifying the factors that influence the efficiency score of railways in terms of accident risk using the IBM SPSS. The results show that GDP per capita and density of population in the selected countries have a strong influence on the efficiency of railways. The expected outcome of this research may contribute to better understanding of the factors that influence the efficiency score of railways in term of accident risk at LCs and develop preventative measures. Keywords: level crossings, accidents, efficiency score and influencing factor

Science with the World Space Observatory - Ultraviolet

The World Space Observatory-Ultraviolet (WSO-UV) will provide access to the UV range during the next decade. The instrumentation on board will allow to carry out high resolution imaging, high sensitivity imaging, high resolution (R~55000) spectroscopy and low resolution (R~2500) long slit spectroscopy. In this contribution, we briefly outline some of the key science issues that WSO-UV will address during its lifetime. Among them, of special interest are: the study of galaxy formation and the intergalactic medium; the astronomical engines; the Milky Way formation and evol ution, and the formation of the Solar System and the atmospheres of extrasolar p lanets.Comment: Just one text file (aigomezdecastro.tex). To be published in the proceeding of the conference: "New Quest in Stellar Astrophysics II: UV properties of evolved stellar populations" held in Puerto Vallarta - Mexico, in april 200

Bessel beam propagation: Energy localization and velocity

The propagation of a Bessel beam (or Bessel-X wave) is analyzed on the basis of a vectorial treatment. The electric and magnetic fields are obtained by considering a realistic situation able to generate that kind of scalar field. Specifically, we analyze the field due to a ring-shaped aperture over a metallic screen on which a linearly polarized plane wave impinges. On this basis, and in the far field approximation, we can obtain information about the propagation of energy flux and the velocity of the energy.Comment: 6 pages, 4 figure

Hydropyrolysis of high molecular weight organic matter in Murchison

Hydropyrolysis of the Murchison macromolecular material releases polyaromatic compounds including phenanthrene, carbazole, fluoranthene, pyrene, chrysene, perylene, benzoperylene and coronene units with varying degrees of alklyation

Reply to Comment by Borisenko et al. on article `A de Haas-van Alphen study of the Fermi surfaces of superconducting LiFeP and LiFeAs'

Recently, Borisenko et al have posted a Comment (arXiv:1108.1159) where they suggest an alternative interpretation of our de Haas-van Alphen (dHvA) measurements on the superconductor LiFeAs. In our original paper (arXiv:1107.4375) we concluded that our measurements of the bulk Fermi surface were not consistent with the surface bands observed thus far by ARPES. Borisenko et al dispute this and suggest the two measurements are consistent if some of the orbits we observe are due to magnetic breakdown. We argue here that this scenario is inconsistent with the experimental data and therefore that our original conclusion stands.Comment: 4 pages with figure

Signatures of High-Intensity Compton Scattering

We review known and discuss new signatures of high-intensity Compton scattering assuming a scenario where a high-power laser is brought into collision with an electron beam. At high intensities one expects to see a substantial red-shift of the usual kinematic Compton edge of the photon spectrum caused by the large, intensity dependent, effective mass of the electrons within the laser beam. Emission rates acquire their global maximum at this edge while neighbouring smaller peaks signal higher harmonics. In addition, we find that the notion of the centre-of-mass frame for a given harmonic becomes intensity dependent. Tuning the intensity then effectively amounts to changing the frame of reference, going continuously from inverse to ordinary Compton scattering with the centre-of-mass kinematics defining the transition point between the two.Comment: 25 pages, 16 .eps figure

The XMM-Newton spectral-fit database

The XMM-Newton spectral-fit database is an ongoing ESA funded project aimed to construct a catalogue of spectral-fitting results for all the sources within the XMM-Newton serendipitous source catalogue for which spectral data products have been pipeline-extracted (~ 120,000 X-ray source detections). The fundamental goal of this project is to provide the astronomical community with a tool to construct large and representative samples of X-ray sources by allowing source selection according to spectral properties.Comment: Conference proceedings of IAU Symposium 304: Multiwavelength AGN surveys and studie

Subduction Duration and Slab Dip

The dip angles of slabs are among the clearest characteristics of subduction zones, but the factors that control them remain obscure. Here, slab dip angles and subduction parameters, including subduction duration, the nature of the overriding plate, slab age, and convergence rate, are determined for 153 transects along subduction zones for the present day. We present a comprehensive tabulation of subduction duration based on isotopic ages of arc initiation and stratigraphic, structural, plate tectonic and seismic indicators of subduction initiation. We present two ages for subduction zones, a long‐term age and a reinitiation age. Using cross correlation and multivariate regression, we find that (1) subduction duration is the primary parameter controlling slab dips with slabs tending to have shallower dips at subduction zones that have been in existence longer; (2) the long‐term age of subduction duration better explains variation of shallow dip than reinitiation age; (3) overriding plate nature could influence shallow dip angle, where slabs below continents tend to have shallower dips; (4) slab age contributes to slab dip, with younger slabs having steeper shallow dips; and (5) the relations between slab dip and subduction parameters are depth dependent, where the ability of subduction duration and overriding plate nature to explain observed variation decreases with depth. The analysis emphasizes the importance of subduction history and the long‐term regional state of a subduction zone in determining slab dip and is consistent with mechanical models of subduction