Galactic cosmic rays on extrasolar Earth-like planets: II. Atmospheric implications

(abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields. As described in the companion article (Paper I), a weak magnetic field results in a high flux of galactic cosmic rays to the top of the planetary atmosphere. We investigate effects that may result from a high flux of galactic cosmic rays both throughout the atmosphere and at the planetary surface. Using an air shower approach, we calculate how the atmospheric chemistry and temperature change under the influence of galactic cosmic rays for Earth-like (N_2-O_2 dominated) atmospheres. We evaluate the production and destruction rate of atmospheric biosignature molecules. We derive planetary emission and transmission spectra to study the influence of galactic cosmic rays on biosignature detectability. We then calculate the resulting surface UV flux, the surface particle flux, and the associated equivalent biological dose rates. We find that up to 20% of stratospheric ozone is destroyed by cosmic-ray protons. The reduction of the planetary ozone layer leads to an increase in the weighted surface UV flux by two orders of magnitude under stellar UV flare conditions. The resulting biological effective dose rate is, however, too low to strongly affect surface life. We also examine the surface particle flux: For a planet with a terrestrial atmosphere, a reduction of the magnetic shielding efficiency can increase the biological radiation dose rate by a factor of two. For a planet with a weaker atmosphere (with a surface pressure of 97.8 hPa), the planetary magnetic field has a much stronger influence on the biological radiation dose, changing it by up to two orders of magnitude.Comment: 14 pages, 9 figures, published in A&

Galactic cosmic rays on extrasolar Earth-like planets I. Cosmic ray flux

(abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields, especially in the case of planets more massive than Earth (super-Earths). Planetary magnetic fields, however, constitute one of the shielding layers that protect the planet against cosmic-ray particles. In particular, a weak magnetic field results in a high flux of Galactic cosmic rays that extends to the top of the planetary atmosphere. We wish to quantify the flux of Galactic cosmic rays to an exoplanetary atmosphere as a function of the particle energy and of the planetary magnetic moment. We numerically analyzed the propagation of Galactic cosmic-ray particles through planetary magnetospheres. We evaluated the efficiency of magnetospheric shielding as a function of the particle energy (in the range 16 MeV $\le$ E $\le$ 524 GeV) and as a function of the planetary magnetic field strength (in the range 0 ${M}_\oplus$ $\le$ {M} $\le$ 10 ${M}_\oplus$). Combined with the flux outside the planetary magnetosphere, this gives the cosmic-ray energy spectrum at the top of the planetary atmosphere as a function of the planetary magnetic moment. We find that the particle flux to the planetary atmosphere can be increased by more than three orders of magnitude in the absence of a protecting magnetic field. For a weakly magnetized planet (${M}=0.05\,{M}_{\oplus}$), only particles with energies below 512 MeV are at least partially shielded. For a planet with a magnetic moment similar to Earth, this limit increases to 32 GeV, whereas for a strongly magnetized planet ($M=10.0\,{M}_{\oplus}$), partial shielding extends up to 200 GeV. We find that magnetic shielding strongly controls the number of cosmic-ray particles reaching the planetary atmosphere. The implications of this increased particle flux are discussed in a companion article.Comment: 10 pages, 9 figures; accepted in A&

Consommation des jeunes et jeunes adultes en fin de semaine : Evolution entre 2011, 2013 et 2015

Parmi les 691 jeunes de 15 à 29 ans qui ont participé au module jeune en 2015, 629 sont sortis au cours des 30 jours précédant la passation de l’enquête. Les réponses données par ces derniers permettent de compléter les résultats déjà obtenus précédemment concernant les consommations des jeunes lors de leur dernière sortie de fin de semaine. De manière générale, il n’existe pas de tendance nette chez les jeunes vers une hausse ou une diminution de la consommation de substances entre 2011 et 2015. L’alcool reste la substance la plus consommée par les jeune

A comparison of HREM and weak beam transmission electron microscopy for the quantitative measurement of the thickness of ferroelectric domain walls

In this paper we present two methods for the quantitative measurement of the thickness of ferroelectric domain walls, one using high-resolution electron microscopy (HREM) and the other weak beam transmission electron microscopy (WBTEM). These techniques can be used to determine the thickness of domain walls at room temperature as well as close to the ferroelectric to paraelectric phase transition. The first method allows a direct visualization of the lattice distortion across the domain wall, by measuring the continuous deviation of a set of planes with respect to the undistorted lattice. The second method consists in a quantitative analysis of the thickness fringes that appear on weak beam images of inclined domain walls. By fitting simulated fringe profiles to experimental ones, we can extract the thickness of the domain walls in a quantitative way. These two complementary techniques lead to a complete characterization of the thickness of ferroelectric domain walls over a wide range of specimen thicknesses at different magnifications. As an example we apply these methods to ferroelectric domain walls in PbTiO3 The domain wall thickness at room temperature is found to be 1.5 ± 0.3 nm using HREM (in very thin samples≈10 nm) and 2.1 ± 0.7 nm using WBTEM (in samples thicker than 30 nm

What is climate finance? Definitions to improve tracking and scale up of climate finance.

This brief explains CPI’s understanding and definition of key climate finance terms and the reasons for these definitions to inform the debate and build a common understanding among stakeholders. • Policy makers, investors, financial intermediaries and analysts do not always have the same understanding of key climate finance terms and concepts. Building a common understanding of key climate finance terminology would improve ongoing discussions on how best to track climate finance, clarify efforts to measure its effectiveness, and help identify where public sector interventions can best impact the scale up of climate finance. • In its Global Landscape of Climate Finance studies, CPI applies a definition of climate finance which counts public and private investment costs plus public framework expenditures but excludes revenue support. We use this to track current climate mitigation and adaptation financing, while reducing double counting as far as possible. In detailed case studies, we also analyze other costs and public revenue support provided over the lifetime of investments. • Clarifying project-level climate finance terminology can help policymakers better understand the range of options available for public actors to both reduce the costs and boost the revenues of low-carbon and climate-resilient projects in order to make investment more financially attractive for the private sector. It also helps to show that public framework expenditures are an essential part of the transition towards low-carbon and climate-resilient economies

Enquêtes populationnelles sur la victimisation et la délinquance chez les jeunes dans les cantons de Vaud et Zurich : Les jeunes non-exclusivement hétérosexuel∙le∙s : populations davantage exposées ?

Les personnes lesbiennes, gays, bisexuelles et transgenres (LGBT) sont nombreuses à être Les personnes lesbiennes, gays, bisexuelles et transgenres (LGBT) sont nombreuses à être confrontées à des violences psychologiques, verbales et/ou physiques. En effet, les jeunes faisantpartie de minorités sexuelles sont plus fréquemment victimisé·e·s à l’école que leurs pair·e·s. Ils·Elles sont par exemple plus nombreux·euses à avoir été victimes de vols ou à avoir eu leurs affaires cassées et sont également significativement plus nombreux·euses à avoir manqué l’école du fait qu’ils·elles ne s’y sentaient pas en sécurité. Relevons également que la part de jeunes lesbiennes, gays, bisexuel·le·s (LGB) ayant vécu des rapports sexuels non consentis est également plus importante. Les jeunes faisant partie de minorité sexuelles sont également plus souvent victimes de harcèlement. Les données de la dernière enquête « Youth Risk Behavior Survey » (YRBS, 2015) indiquent que 34% des jeunes LGB, 25% des jeunes en questionnement quant à leur orientation sexuelle et 19% des jeunes hétérosexuel·le·s ont été harcelé à l’école au cours de 12 derniers mois. Enfin, les adolescents et jeunes hommes faisant partie de minorités sexuelles sont plus souvent victimes de violences homophobes. Le premier objectif du présent rapport consiste à déterminer le taux de jeunes de 15 ans scolarisé·e·s n’ayant pas une attirance sexuelle exclusivement hétérosexuelle dans ces deux cantons et le second à déterminer dans quelle mesure ces personnes sont plus touchées par différentes problématiques comme la victimisation, la consommation de substances psychoactives, le harcèlement en milieu scolaire, la délinquance, ou encore les problèmes de santé

Innovative chemotherapeutical treatment options for alveolar and cystic echinococcosis

Echinococcus granulosus and Echinococcus multilocularis are cestode parasites, of which the metacestode (larval) stages cause the diseases cystic echinococcosis (CE) and alveolar echinococcosis (AE), respectively. Albendazole and mebendazole are presently used for chemotherapeutical treatment. However, these benzimidazoles do not appear to be parasiticidal in vivo against AE. In addition, failures in drug treatments as well as the occurrence of side-effects have been reported. New drugs are needed to cure AE and CE, which are considered to be neglected diseases. Strategies currently being implemented to identify novel chemotherapeutical treatment options include (i) conventional primary in vitro testing of broad-spectrum anti-infective drugs, either in parallel with, or followed by, animal experimentation; (ii) studies of drugs which interfere with the proliferation of cancer cells and of Echinococcus metacestodes; (iii) exploitation of the similarities between the parasite and mammalian signalling machineries, with a special focus on targeting specific signalling receptors; (iv) in silico approaches, employing the current Echinococcus genomic database information to search for suitable targets for compounds with known modes of action. In the present article, we review the efforts toward obtaining better anti-parasitic compounds which have been undertaken to improve chemotherapeutical treatment of echinococcosis, and summarize the achievements in the field of host-parasite interactions which may also lead to new immuno-therapeutical option

An anionic phosphenium complex as an ambident nucleophile

A unique anionic phosphenium complex was prepared from reaction of an N-heterocyclic chlorophosphine with Collman's reagent or K[HFe(CO)(4)]/NaH and characterized by spectral and XRD data. The complex behaves as an ambident nucleophile. Reactions with acetic acid, ClSnPh3, and a further equivalent of an N-heterocyclic chlorophosphine proceed via electrophilic functionalization at the metal site to yield appropriate mono- or bis-phosphenium complexes. Reaction with MeI at -70 degrees C produces a P-alkylation product as the first spectroscopically detectable intermediate, which decays at a higher temperature to give a mixture of free P-methylated N-heterocyclic phosphine and its Fe(CO)(4) complex. The different reaction products were characterized by spectral and XRD data. Computational studies indicate that the NHP units in all complexes display p-acceptor behaviour but show no disposition to adopt phosphide-like character or formally oxidize the metal centre.Peer reviewe