Warp evidences in precessing galactic bar models

Most galaxies have a warped shape when they are seen from an edge-on point of view. The reason for this curious form is not completely known so far and in this work we apply dynamical system tools to contribute to its explanation. Starting from a simple, but realistic, model formed by a bar and a disc, we study the effect produced by a small misalignment between the angular momentum of the system and its angular velocity. To this end, a precession model is developed and considered, assuming that the bar behaves like a rigid body. After checking that the periodic orbits inside the bar keep being the skeleton of the inner system, even after inflicting a precession to the potential, we compute the invariant manifolds of the unstable periodic orbits departing from the equilibrium points at the ends of the bar to get evidences of their warped shapes. As it is well known, the invariant manifolds associated with these periodic orbits drive the arms and rings of barred galaxies and constitute the skeleton of these building blocks. Looking at them from a side-on viewpoint, we find that these manifolds present warped shapes as those recognized in observations. Lastly, test particle simulations have been performed to determine how the stars are affected by the applied precession, confirming this way the theoretical results obtained.Comment: 14 pages, 21 figures, Accepted for publication in A&A (15th Jan 2016

Hyphomycètes aquatiques : importance dans la décomposition des litières

Les auteurs comparent les communautés d'hyphomycètes aquatiques récoltés dans l'écume de 7 cours d'eau du Béarn et des Landes. L'abondance de spores observées dans les deux régions diffère considérablement (174-1175 spores/µl en Béarn et 2-57 spores/µl dans les Landes) tandis que les variations de richesse spécifique apparaissent faibles. L'influence de la végétation riveraine et du pH de l'eau est discutée.Des expériences de dégradation in vitro montrent que des souches isolées de Tetracladium marchalianum, Heliscus lugdunensis et dans une moindre mesure Anguillospora longissima présentent une activité cellulolytique. T. marchalianum et H. lugdunensis, participent activement à la décomposition de litière de saule blanc, avec respectivement 21,7 et 18,2 % de dégradation après 5 semaines à 18°C.Aquatic hyphomycete communities from the foam of seven streams in the Bearn and Landes regions of France were compared at four different dates. The total number of species was similar in the two regions, but common species (> 5 spores/µl) in the Bearn were twice as abundant as in the Landes. Mean spore concentrations in the Bearn and Landes streams were in a ratio of 10 : 1. In the Bearn, spore concentration and the number of fungal species increased considerably in autumn, subsequent to the fall of leaf litter into the streams. Analysis of variance of spore concentrations (original or transformed data) in the two regions showed that date, station and the interaction of these two factors were highly significant parameters (P ANOVA < 0.0001). Alatospora acuminate was the commonest species both in the Bearn (77 % annual mean) and in the Landes (41 %). After A. acuminata, Clavatospora stellata (7 %) and Tetracladium marchalianum (4 %,) in the Bearn, Flagellospora curvula (28 %) and Clavastospora longibrachiata (20 %) in the Landes were the dominant species of the mycoflora. Five species new to France were noted : Actinospora megalospora Ingold, Camposporium pellucidum (Grave) Hugues, Diplocladiella scalaroides Arnaud, Flabellospora acuminata Descals and Triscelophorus monosporus Ingold. The difference in fungal richness between the two regions was suggested to be due to the composition of the riparian vegetation, the phenology of the litter fall, the presence (or absence) of plant matter accumulation in the stream, and the pH of the stream water. Litter deposits in the Landes streams were rare and made up exclusivey of pine needles, the few deciduous leaves which fall being exported to surrounding lakes and to the ocean. Water pH was always low (5.0-5.5). The riparian vegetation of the Bearn streams, on the contrary, was abundant and varied Cash, common locust-tree, alder, willow, oak, chestnut, poplar). Moreover the neutral or weakly acid pH of the Bearn streams (6.3-7.0) seemed to favour fungal diversity (cf. BÄRLOCHER and ROSSET, 1981; WOOD-EGGENSCHWILLER and BARLOCHER, 1983).Single spore isolates of Anguillospora langissima (de Wild.) Ingold, Heliscus lugdunensis Saccardo et Therry and Tetraclacium marchalianum De Wild were obtained from decomposing leaf litter in the Bearn streams. In laboratory experiments, the degradation activity of each species was tested both on sterilized paper cellulose and white willow leaf litter. The cellutolytic activity of fungal cultures was significant when compared with controls (t test). After 5 weeks at 18 °C, mass loss was 8.6 % for A.longissima and 10.0 % for H.lugdunensis and T.marchalianum. Aeration stimulated cellulose degradation for T.marchalianum (16.6 %) only. With willow leaves as substrate, degradation was greater for T.marchalianum (22.7 %) than for N. lugdunensis (11.8 %) and A. longissima (6.2 %, non-significant)

Acetate as an active metabolite of ethanol: studies of locomotion, loss of righting reflex, and anxiety in rodents

It has been postulated that a number of the central effects of ethanol are mediated via ethanol metabolites: acetaldehyde and acetate. Ethanol is known to produce a large variety of behavioral actions such anxiolysis, narcosis, and modulation of locomotion. Acetaldehyde contributes to some of those effects although the contribution of acetate is less known. In the present studies, rats and mice were used to assess the acute and chronic effects of acetate after central or peripheral administration. Male Sprague-Dawley rats were used for the comparison between central (intraventricular, ICV) and peripheral (intraperitoneal, IP) administration of acute doses of acetate on locomotion. CD1 male mice were used to study acute IP effects of acetate on locomotion, and also the effects of chronic oral consumption of acetate (0, 500, or 1000 mg/l, during 7, 15, 30, or 60 days) on ethanol- (1.0, 2.0, 4.0, or 4.5 g/kg, IP) induced locomotion, anxiolysis, and loss of righting reflex (LORR). In rats, ICV acetate (0.7–2.8 μmoles) reduced spontaneous locomotion at doses that, in the case of ethanol and acetaldehyde, had previously been shown to stimulate locomotion. Peripheral acute administration of acetate also suppressed locomotion in rats (25–100 mg/kg), but not in mice. In addition, although chronic administration of acetate during 15 days did not have an effect on spontaneous locomotion in an open field, it blocked ethanol-induced locomotion. However, ethanol-induced anxiolysis was not affected by chronic administration of acetate. Chronic consumption of acetate (up to 60 days) did not have an effect on latency to, or duration of LORR induced by ethanol, but significantly increased the number of mice that did not achieve LORR. The present work provides new evidence supporting the hypothesis that acetate should be considered a centrally-active metabolite of ethanol that contributes to some behavioral effects of this alcohol, such as motor suppression

Role of dopamine–adenosine interactions in the brain circuitry regulating effort-related decision making: insights into pathological aspects of motivation

Brain dopamine, particularly in the nucleus accumbens, has been implicated in activational aspects of motivation and effort-related processes. Accumbens dopamine depletions reduce the tendency of rats to work for food, and alter effort-related decision making, but leave aspects of food motivation such as appetite intact. Recent evidence indicates that the purine neuromodulator adenosine, largely through actions on adenosine A2A receptors, also participates in regulating effort-related processes. Adenosine A2A antagonists can reverse the effects of dopamine D2 antagonists on effort-related choice, and intra- accumbens injections of adenosine A2A agonists produce effects that are similar to those induced by accumbens dopamine depletion or antagonism. These studies have implications for the understanding and treatment of energy-related disorders such as anergia and fatigue in psychiatry and neurology

Report of IRPA task group on the impact of the eye lens dose limits

In 2012 IRPA established a task group (TG) to identify key issues in the implementation of the revised eye lens dose limit. The TG reported its conclusions in 2013. In January 2015, IRPA asked the TG to review progress with the implementation of the recommendations from the early report and to collate current practitioner experience. This report presents the results of a survey on the view of the IRPA professionals on the new limit to the lens of the eye and on the wider issue of tissue reactions. Recommendations derived from the survey are presented. This report was approved by IRPA Executive Council on 31 January 2017

Editorial: Recent advances in hazelnut (Corylus spp.)

The European hazelnut (Corylus avellana L.) of the genus Corylus is a major species of interest for nutritional use, and its nuts are widely used worldwide in the chocolate, confectionery, and bakery industries. Other Corylus species, including C. americana, C. heterophylla, and C. colurna, are of local interest for commercial uses and provide important genetic resources for breeding. The global production of hazelnut has increased since the beginning of the last century, especially in the last 10 years in response to the demands of the confectionery industry, which processes about 90% of the harvested nuts. Cultivation of this nut has expanded in several traditional countries as well as in new areas, including Chile, South Africa, and Australia. Therefore, this Research Topic devoted to European hazelnut and its related species has been designed with the aim of assembling an effective-knowledge platform based on recent research carried out in the Corylus spp. sector. The Research Topic brings together some of the latest research outputs in hazelnut cultivation, genetic resources, and post-harvest processing, thanks to the excellent response to the call which resulted in the publication of 25 original articles. We found the edition and selection of articles for this book very inspiring and rewarding. We also thank the editorial staff and reviewers for their efforts and help during the process. The scientific contributions are briefly discussed below, grouped into seven sections according to the main topics proposed during the Research Topic launch.info:eu-repo/semantics/publishedVersio

Rotating black holes in Eddington-inspired Born-Infeld gravity: an exact solution

We find an exact, rotating charged black hole solution within Eddington-inspired Born-Infeld gravity. To this end we employ a recently developed correspondence or {\it mapping} between modified gravity models built as scalars out of contractions of the metric with the Ricci tensor, and formulated in metric-affine spaces (Ricci-Based Gravity theories) and General Relativity. This way, starting from the Kerr-Newman solution, we show that this mapping bring us the axisymmetric solutions of Eddington-inspired Born-Infeld gravity coupled to a certain model of non-linear electrodynamics. We discuss the most relevant physical features of the solutions obtained this way, both in the spherically symmetric limit and in the fully rotating regime. Moreover, we further elaborate on the potential impact of this important technical progress for bringing closer the predictions of modified gravity with the astrophysical observations of compact objects and gravitational wave astronomy.Comment: 17 double column pages, 7 figures, revtex4-1 styl

An overview on extremity dosimetry in medical applications

Some activities of EURADOS Working Group 9 (WG9) are presently funded by the European Commission (CONRAD project). The objective of WG9 is to promote and co-ordinate research activities for the assessment of occupational exposures to staff at workplaces in interventional radiology (IR) and nuclear medicine. For some of these applications, the skin of the fingers is the limiting organ for individual monitoring of external radiation. Therefore, sub-group 1 of WG9 deals with the use of extremity dosemeters in medical radiation fields. The wide variety of radiation field characteristics present in a medical environment together with the difficulties in measuring a local dose that is representative for the maximum skin dose, usually with one single detector, makes it difficult to perform accurate extremity dosimetry. Sub-group 1 worked out a thorough literature review on extremity dosimetry issues in diagnostic and therapeutic nuclear medicine and positron emission tomography, interventional radiology and interventional cardiology and brachytherapy. Some studies showed that the annual dose limits could be exceeded if the required protection measures are not taken, especially in nuclear medicine. The continuous progress in new applications and techniques requires an important effort in radiation protection and trainin

An overview of the use of extremity dosemeters in some European countries for medical applications

Some medical applications are associated with high doses to the extremities of the staff exposed to ionising radiation. At workplaces in nuclear medicine, interventional radiology, interventional cardiology and brachytherapy, extremities can be the limiting organs as far as regulatory dose limits for workers are concerned. However, although the need for routine extremity monitoring is clear for these applications, no data about the status of routine extremity monitoring reported by different countries was collected and analysed so far, at least at a European level. In this article, data collected from seven European countries are presented. They are compared with extremity doses extracted from dedicated studies published in the literature which were reviewed in a previous publication. The analysis shows that dedicated studies lead to extremity doses significantly higher than the reported doses, suggesting that either the most exposed workers are not monitored, or the dosemeters are not routinely worn or not worn at appropriate position

Comparison of organ doses and image quality between CT and flat panel XperCT scans in wrist and inner ear examinations

The aim of this study was to evaluate and compare organ doses delivered to patients in wrist and petrous bone examinations using a multislice spiral computed tomography (CT) and a C-arm cone-beam CT equipped with a flat-panel detector (XperCT). For this purpose, doses to the target organ, i.e. wrist or petrous bone, together with those to the most radiosensitive nearby organs, i.e. thyroid and eye lens, were measured and compared. Furthermore, image quality was compared for both imaging systems and different acquisition modes using a Catphan phantom. Results show that both systems guarantee adequate accuracy for diagnostic purposes for wrist and petrous bone examinations. Compared with the CT scanner, the XperCT system slightly reduces the dose to target organs and shortens the overall duration of the wrist examination. In addition, using the XperCT enables a reduction of the dose to the eye lens during head scans (skull base and ear examinations