Reflection high-energy electron diffraction patterns of CrSi_2 films on (111) silicon

Highly oriented films of the semiconducting transition metal silicide, CrSi2, were grown on (111) silicon substrates, with the matching crystallographic faces being CrSi_2(001)/Si(111). Reflection high‐energy electron diffraction (RHEED) yielded symmetric patterns of sharp streaks. The expected streak spacings for different incident RHEED beam directions were calculated from the reciprocal net of the CrSi_2(001) face and shown to match the observed spacings. The predominant azimuthal orientation of the films was thus determined to be CrSi_2〈210〉∥Si〈110〉. This highly desirable heteroepitaxial relationship may be described with a common unit mesh of 51 Å^2 and a mismatch of −0.3%. RHEED also revealed the presence of limited film regions of a competing azimuthal orientation, CrSi_2〈110〉∥Si〈110〉. A new common unit mesh for this competing orientation is suggested; it possesses an area of 612 Å^2 and a mismatch of −1.2%

Pre-Congestion Notification (PCN) Architecture

This document describes a general architecture for flow admission and termination based on pre-congestion information in order to protect the quality of service of established, inelastic flows within a single Diffserv domain.\u

Channeling of MeV ions in polyatomic epitaxial films: ReSi2 on Si(100)

Channeling of a He beam in the energy range from 1.4 to 2.7 MeV in a polyatomic epitaxial ReSi2 film (∼150 nm thick) was studied by detecting backscattered He ions. The critical angles and the minimum yields of both the heavy (Re) and the light (Si) elements are obtained directly from backscattering measurements. The critical angles of both Re and Si scale as √1/E. The critical angle of Re is always about 2.3 times that of Si. The minimum yields of both Re and Si do not change over this energy range. The minimum yield of Re (2%) is about 1/7 that of Si (14%). The results are explained qualitatively and quantitatively by the continuum model suitably extended for polyatomic crystals. An important corollary is that a high value for the minimum yield of the light element in a polyatomic single crystal does not necessarily mean that the sublattice of the light element is disordered

Midgut microbiota of the malaria mosquito vector Anopheles gambiae and Interactions with plasmodium falciparum Infection

The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.Institut de Recherche pour le Developpement (IRD); French Agence Nationale pour la Recherche [ANR-11-BSV7-009-01]; European Community [242095, 223601]info:eu-repo/semantics/publishedVersio

Oocyte expression with injection of purified T7 RNA polymerase.

International audienceThe Xenopus oocyte is a widely used system for protein expression. Investigators have had the choice between two different techniques: injection into the cytoplasm of in vitro transcribed complementary RNA (cRNA) or injection into the nucleus of complementary DNA (cDNA). We report on a third expression technique that is based on the combined injection of cDNA and purified T7 RNA polymerase directly into the cytoplasm of oocytes

Prediction and Topological Models in Neuroscience

In the last two decades, philosophy of neuroscience has predominantly focused on explanation. Indeed, it has been argued that mechanistic models are the standards of explanatory success in neuroscience over, among other things, topological models. However, explanatory power is only one virtue of a scientific model. Another is its predictive power. Unfortunately, the notion of prediction has received comparatively little attention in the philosophy of neuroscience, in part because predictions seem disconnected from interventions. In contrast, we argue that topological predictions can and do guide interventions in science, both inside and outside of neuroscience. Topological models allow researchers to predict many phenomena, including diseases, treatment outcomes, aging, and cognition, among others. Moreover, we argue that these predictions also offer strategies for useful interventions. Topology-based predictions play this role regardless of whether they do or can receive a mechanistic interpretation. We conclude by making a case for philosophers to focus on prediction in neuroscience in addition to explanation alone

A key role for stimulus-specific updating of the sensory cortices in the learning of stimulus-reward associations

Successful adaptive behavior requires the learning of associations between stimulus-specific choices and rewarding outcomes. Most research on the mechanisms underlying such processes has focused on subcortical reward-processing regions, in conjunction with frontal circuits. Given the extensive stimulus-specific coding in the sensory cortices, we hypothesized they would play a key role in the learning of stimulus-specific reward associations. We recorded electrical brain activity (EEG) during a learning-based, decision-making, gambling task where, on each trial, participants chose between a face and a house and then received feedback (gain or loss). Within each 20-trial set, either faces or houses were more likely to predict a gain. Results showed that early feedback processing (~200-1200ms) was independent of the choice made. In contrast, later feedback processing (~1400-1800ms) was stimulus-specific, reflected by decreased alpha power (reflecting increased cortical activity) over face-selective regions. For winning-versus-losing after a face choice, but not after a house choice. Finally, as the reward association was learned in a set, there was increasingly stronger attentional bias towards the more likely winning stimulus, reflected by increasing attentional-orienting-related brain activity and increasing likelihood of choosing that stimulus. These results delineate the processes underlying the updating of stimulus-reward associations during feedback-guided learning, which then guides future attentional allocation and decision making

Impact of the insulin and glucose content of the postoperative fluid on the outcome after pediatric cardiac surgery

INTRODUCTION: The aim of this study was to investigate the role of the insulin and glucose content of the maintenance fluid in influencing the outcomes of pediatric patients undergoing heart surgery. METHODS: A total of 2063 consecutive pediatric patients undergoing cardiac surgery were screened between 2003 and 2008. A dextrose and an insulin propensity-matched group were constructed. In the dextrose model, 5% and 10% dextrose maintenance infusions were compared below 20 kg of weight. RESULTS: A total of 171 and 298 pairs of patients were matched in the insulin and glucose model, respectively. Mortality was lower in the insulin group (12.9% vs. 7%, p = 0.049). The insulin group had longer intensive care unit (ICU) stay [days, 10.9 (5.8–18.4) vs. 13.7 (8.2–21), p = 0.003], hospital stay [days, 19.8 (13.6–26.6) vs. 22.7 (17.6–29.7), p < 0.01], duration of mechanical ventilation [hours, 67 (19–140) vs. 107 (45–176), p = 0.006], and the incidence of severe infections (18.1% vs. 28.7%, p = 0.01) and dialysis (11.7% vs. 24%, p = 0.001) was higher. In the dextrose model, the incidence of pulmonary complications (13.09% vs. 22.5%, p < 0.01), low cardiac output (17.11% vs. 30.9%, p < 0.01), and severe infections (10.07% vs. 20.5%, p < 0.01) was higher, and the duration of the hospital stay [days, 16.4 (13.1–21.6) vs. 18.1 (13.8–24.6), p < 0.01] was longer in the 10% dextrose group. CONCLUSIONS: Insulin treatment appeared to decrease mortality, and lower glucose content was associated with lower occurrence of adverse events

Divergent Switchgrass Cultivars Modify Cereal Aphid Transcriptomes

Schizaphis graminum Rondani (Hemiptera: Aphididae) and Sipha flava Forbes (Hemiptera: Aphididae) are two common pests of bioenergy grasses. Despite the fact that they are both considered generalists, they differ in their ability to colonize Panicum virgatum cultivars. For example, S. flava colonizes both P. virgatum cv. Summer and P. virgatum cv. Kanlow whereas S. graminum can only colonize Summer. To study the molecular responses of these aphids to these two switchgrass cultivars, we generated de novo transcriptome assemblies and compared the expression profiles of aphids feeding on both cultivars to profiles associated with feeding on a highly susceptible sorghum host and a starvation treatment. Transcriptome assemblies yielded 8,428 and 8,866 high-quality unigenes for S. graminum and S. flava, respectively. Overall, S. graminum responded strongly to all three treatments after 12 h with an upregulation of unigenes coding for detoxification enzymes while major transcriptional changes were not observed in S. flava until 24 h. Additionally, while the two aphids responded to the switchgrass feeding treatment by downregulating unigenes linked to growth and development, their responses to Summer and Kanlow diverged significantly. Schizaphis graminum upregulated more unigenes coding for stress-responsive enzymes in the Summer treatment compared to S. flava; however, many of these unigenes were actually downregulated in the Kanlow treatment. In contrast, S. flava appeared capable of overcoming host defenses by upregulating a larger number of unigenes coding for detoxification enzymes in the Kanlow treatment. Overall, these findings are consistent with previous studies on the interactions of these two cereal aphids to divergent switchgrass hosts