Sterols associated with small unilamellar vesicles (SUVs): intrinsic mobility role for 1H NMR detection.

International audienceSmall unilamellar vesicles (SUVs) of phospholipids are often used as a membrane model system for studying the interaction of molecules. When using NMR under the standard liquid-state conditions, SUV phospholipid proton spectra can be recorded, exhibiting sharp signals. This is not only because of the fast vesicular tumbling but also because of the combination of this tumbling with the individual motion of the lipids inside the bilayer. This appears evident because addition of cholesterol is responsible of broader resonances because of the slowing down of the lipid motion. On the other hand, no (1)H signal is detected for cholesterol in the bilayer. This lack of detection of the inserted molecules explains why generally SUVs are not considered as a good model for NMR studies under the standard liquid-state conditions. Here, we use two other sterols in order to demonstrate that an increase of the molecular mobility inside the bilayer could allow the detection of their proton resonances. For desmosterol and lanosterol, which show higher mobility inside the bilayer, with increasing lateral diffusion rates, (1)H sterol signals are detected in contrast to cholesterol. For the fast diffusing lanosterol, no significant improvement in detection is observed using deuterated lipids, demonstrating that homonuclear dipolar coupling is fully averaged out. Furthermore, in the case of low mobility such as for cholesterol, the use of a fast magic angle spinning probe is shown to be efficient to recover the full proton spectrum

Effects of Rewarding and Unrewarding Experiences on the Response to Host-induced Plant Odors of the Generalist Parasitoid Cotesia marginiventris (Hymenoptera: Braconidae)

Associative learning is known to modify foraging behavior in numerous parasitic wasps. This is in agreement with optimal foraging theory, which predicts that the wasps will adapt their responses to specific cues in accordance with the rewards they receive while perceiving these cues. Indeed, the generalist parasitoid Cotesia marginiventris shows increased attraction to a specific plant odor after perceiving this odor during contact with hosts. This positive associative learning is common among many parasitoids, but little is known about the effects of unrewarding host searching events on the attractiveness of odors. To study this, preferences of female C. marginiventris for herbivore-induced odors of three plant species were tested in a six-arm olfactometer after the wasps perceived one of these odors either i) without contacting any caterpillars, ii) while contacting the host caterpillar Spodoptera littoralis, or iii) while contacting the non-host caterpillar Pieris rapae. The results confirm the effects of positive associative learning, but showed no changes in innate responses to the host-induced odors after "negative” experiences. Hence, a positive association is made during an encounter with hosts, but unsuccessful host-foraging experiences do not necessarily lead to avoidance learning in this generalist parasitoi

Polarization of resonance X-ray lines from clusters of galaxies

As is known, resonant scattering can distort the surface-brightness profiles of clusters of galaxies in X-ray lines. We demonstrate that the scattered line emission should be polarized and possibly detectable with near-future X-ray polarimeters. Spectrally-resolved mapping of a galaxy cluster in polarized X-rays could provide valuable independent information on the physical conditions, in particular element abundances and the characteristic velocity of small-scale turbulent motions, in the intracluster gas. The expected degree of polarization is of the order of 10% for richest regular clusters (e.g. Coma) and clusters whose X-ray emission is dominated by a central cooling flow (e.g. Perseus or M87/Virgo).Comment: 12 pages, 13 figures, submitted to MNRA

A Self-biased Current Source, using an Asymmetric Bulk-modified MOS Composite Transistor

In this work a new topology for a self-biased current reference, based on an asymmetric bulk-modified MOS (ABM) composite transistor is presented. Two current references based in this technique were designed: a 13.5nA current reference in a 1.5μm CMOS technology, and a 100nA current reference in a 0.18μm CMOS technology. The latter was designed to minimize the temperature dependence of the output current; the result was less than 5% from 0°C to 100°C, which is a very good result in comparison to other reported similar current references.Agencia Nacional de Investigación e Innovació

The Path towards the European University in the Current EU Legal Framework: the Unita – Universitas Montium Experience

The development of university cooperation at the European level is closely related both to the needs of the single market and to those of an economic and social cohesion functional to a more effective protection of the rights of European citizens. The recent launch of EU university alliances is part of this framework, although the absence of legal instruments explicitly conceived for institutionalised cooperation could undermine the success of the action of alliances. The EU competence in higher education is limited to the support, coordination, and supplement of member state actions (art. 6TFEU). The absence of a harmonising competence circumscribes the possibilities of EU intervention and especially prevents the provision of EU degrees which could replace national diplomas. However, the allocation of funding allows policies capable of effectively influencing the systems of member states (see for instance the EU experience in common agricultural policies sector). In this context, the limits of the existing tools could be almost partially overpassed by the adoption of new regulations or directives, to allow an institutionalised cooperation between universities. The existing solutions offered by the EU legal system are not fully satisfactory, nonetheless, some of them could be useful: among these, the European Economic Interest Grouping (EEIG) is especially interesting

As grandes cheias de Ponte de Lima : uma abordagem metodológica à análise do risco de inundação na perspectiva da directiva relativa à avaliação e gestão dos riscos de inundação

A partir do estudo das grandes cheias do rio Lima, pela sua passagem na vila de Ponte de Lima, pretende dar-se um contributo sobre alguns aspectos metodológicos a considerar no cumprimento da Directiva 2007/60/CE do Parlamento Europeu e do Conselho, de 23 de Outubro de 2007, que tem, por objectivo, “reduzir o risco e as consequências negativas das inundações na União Europeia”.From the study of the major floods of the river Lima, for their passage in the town of Ponte de Lima, is intended to give a contribution on some methodological aspects to be considered in compliance with Directive 2007/60/EC of the European Parliament and the Council of 23 October 2007, which has for objective to "reduce the risk and adverse consequences of floods in the European Union.

Thermal disc emission from a rotating black hole: X-ray polarization signatures

Thermal emission from the accretion disc around a black hole can be polarized, due to Thomson scattering in a disc atmosphere. In Newtonian space, the polarization angle must be either parallel or perpendicular to the projection of the disc axis on the sky. As first pointed out by Stark and Connors in 1977, General Relativity effects strongly modify the polarization properties of the thermal radiation as observed at infinity. Among these effects, the rotation of the polarization angle with energy is particularly useful as a diagnostic tool. In this paper, we extend the Stark and Connors calculations by including the spectral hardening factor, several values of the optical depth of the scattering atmosphere and rendering the results to the expected performances of planned X-ray polarimeters. In particular, to assess the perspectives for the next generation of X-ray polarimeters, we consider the expected sensitivity of the detectors onboard the planned POLARIX and IXO missions. We assume the two cases of a Schwarzschild and an extreme Kerr black hole with a standard thin disc and a scattering atmosphere. We compute the expected polarization degree and the angle as functions of the energy as they could be measured for different inclinations of the observer, optical thickness of the atmosphere and different values of the black hole spin. We assume the thermal emission dominates the X-ray band. Using the flux level of the microquasar GRS 1915+105 in the thermal state, we calculate the observed polarization.Comment: 8 pages, 7 figures, accepted by MNRA

Interventions to Decrease Carotid-Intima Media Thickness in Children and Adolescents With Type 1 Diabetes: A Systematic Review and Meta-Analysis.

INTRODUCTION Hyperglycemia is associated with a higher cardiovascular risk, as evidenced by increased carotid-intima media thickness (CIMT) in youth with diabetes. We conducted a systematic review and meta-analysis to assess the effect of pharmacological or non-pharmacological interventions on CIMT in children and adolescents with prediabetes or diabetes. METHODS We conducted systematic searches of MEDLINE, EMBASE, and CENTRAL, together with supplementary searches in trial registers and other sources for studies completed up to September 2019. Interventional studies assessing ultrasound CIMT in children and adolescents with prediabetes or diabetes were considered for inclusion. Where appropriate, data were pooled across studies using random-effect meta-analysis. Quality was assessed using The Cochrane Collaboration's risk-of-bias tool and a CIMT reliability tool. RESULTS Six studies involving 644 children with type 1 diabetes mellitus were included. No study involved children with prediabetes or type 2 diabetes. Three randomized controlled trials (RCTs) evaluated the effects of metformin, quinapril, and atorvastatin. Three non-randomized studies, with a before-and-after design, evaluated the effects of physical exercise and continuous subcutaneous insulin infusion (CSII). The mean CIMT at baseline ranged from 0.40 to 0.51 mm. The pooled difference in CIMT was -0.01 mm (95% CI: -0.04 to 0.01) for metformin compared to placebo (2 studies; 135 participants; I2: 0%). The difference in CIMT was -0.01 mm (95% CI: -0.03 to 0.01) for quinapril compared to placebo (1 study; 406 participants). The mean change from baseline in CIMT was -0.03 mm (95% CI: -0.14 to 0.08) after physical exercise (1 study; 7 participants). Inconsistent results were reported for CSII or for atorvastatin. CIMT measurement was rated at a higher quality on all reliability domains in 3 (50%) studies. The confidence in results is limited by the low number of RCTs and their small sample sizes, as well as the high risk of bias in before-and-after studies. CONCLUSIONS Some pharmacological interventions may decrease CIMT in children with type 1 diabetes. However, there is great uncertainty with respect to their effects and no strong conclusions can be drawn. Further evidence from larger RCTs is required. SYSTEMATIC REVIEW REGISTRATION PROSPERO, CRD42017075169

Pest-Smart Practices and Early Warning System under Climate Change (A Manual for Rice and Other Crops)

This manual is intended to provide simple and helpful information, especially to farmers and extension agents, in solving pests and diseases issues on rice production in the context of climate change. The publication tackles: the effects of climate change on agriculture; effects of climatic factors on the development of pests and diseases; and importance of an Early Warning System and the pest-smart interventions and recommendations to alleviate problems due to pests and diseases

Constraints on the ionizing flux emitted by T Tauri stars

We present the results of an analysis of ultraviolet observations of T Tauri Stars (TTS). By analysing emission measures taken from the literature we derive rates of ionizing photons from the chromospheres of 5 classical TTS in the range ~10^41-10^44 photons/s, although these values are subject to large uncertainties. We propose that the HeII/CIV line ratio can be used as a reddening-independent indicator of the hardness of the ultraviolet spectrum emitted by TTS. By studying this line ratio in a much larger sample of objects we find evidence for an ionizing flux which does not decrease, and may even increase, as TTS evolve. This implies that a significant fraction of the ionizing flux from TTS is not powered by the accretion of disc material onto the central object, and we discuss the significance of this result and its implications for models of disc evolution. The presence of a significant ionizing flux in the later stages of circumstellar disc evolution provides an important new constraint on disc photoevaporation models.Comment: 8 pages, 5 figures. Accepted for publication in MNRA