553 research outputs found
The Influence of Selected Factors Impacting the Incidence and Severity of Accidents Involving Pedestrian/Bicyclists and Motorized Vehicles in Urban Areas of Louisiana
The primary purpose of this study was to determine the influence of selected demographic, environmental and infrastructure factors on the incidence and severity of traffic accidents involving a motorized vehicle and a non-motorized (pedestrian or bicyclist) individual. Identification of influential factors can aid in developing more effective countermeasures, targeted education and training programs to reduce the fatality and injury risks to vulnerable road users. A total of 9,538 crash data records involving vulnerable road users and motor vehicle drivers were utilized in this study.
Overall, vulnerable road users were found to have higher incidences of impairment than motorized vehicle drivers in accidents involving the two groups. In addition, it was discovered there was a higher incidence of VRU/motorist accidents in mixed use environments and more of these types of accidents occurring at locations other than at an intersection. The time of day with the highest incidence of VRU/motorist accidents is between the hours of 6 p.m. and 12 a.m. The younger drivers and older VRU’s that were most likely to be involved in high severity accidents. Environments with no streetlights in darkness were most likely to experience high incidence of higher severity crashes. Furthermore, it was discovered that the VRU’s displayed higher incidence of distraction in VRU/motorist accidents than the motorized driver.
Based on these findings the researcher concluded that environment and VRU behaviors are major contributors to motorized/non-motorized accidents. The researcher recommends education campaigns to persuade vulnerable road users to develop a better understanding of safety practices when interacting with motorized vehicles. The researcher also recommends further study into the appropriate measures to mitigate environment factors such as lighting and mixed-use developments
Metatranscriptomes reveal functional variation in diatom communities from the Antarctic Peninsula
Functional genomics of diatom-dominated communities from the Antarctic Peninsula was studied using comparative metatranscriptomics. Samples obtained from diatom-rich communities in the Bransfield Strait, the western Weddell Sea and sea ice in the Bellingshausen Sea/Wilkins Ice Shelf yielded more than 500K pyrosequencing reads that were combined to produce a global metatranscriptome assembly. Multi-gene phylogenies recovered three distinct communities, and diatom-assigned contigs further indicated little read-sharing between communities, validating an assembly-based annotation and analysis approach. Although functional analysis recovered a core of abundant shared annotations that were expressed across the three diatom communities, over 40% of annotations (but accounting for <10% of sequences) were community-specific. The two pelagic communities differed in their expression of N-metabolism and acquisition genes, which was almost absent in post-bloom conditions in the Weddell Sea community, while enrichment of transporters for ammonia and urea in Bransfield Strait diatoms suggests a physiological stance towards acquisition of reduced N-sources. The depletion of carbohydrate and energy metabolism pathways in sea ice relative to pelagic communities, together with increased light energy dissipation (via LHCSR proteins), photorespiration, and NO3 uptake and utilization all pointed to irradiance stress and/or inorganic carbon limitation within sea ice. Ice-binding proteins and cold-shock transcription factors were also enriched in sea ice diatoms. Surprisingly, the abundance of gene transcripts for the translational machinery tracked decreasing environmental temperature across only a 4 degrees C range, possibly reflecting constraints on translational efficiency and protein production in cold environments.Portuguese Science Foundation (FCT) [PTDC/MAR/72630]; Spanish Ministry of Economy and Competitiveness (under the scope of the International Polar Year (IPY)) [POL2006-00550/CTM]info:eu-repo/semantics/publishedVersio
: Familias populares e institução escolar : entre autonomia e heteronomia
Version française de "Familias populares e institução escolar : entre autonomia e heteronomia", Educação e Pesquisa, 2010, vol. 36, n°espcial, p. 65-76International audienceL'article se propose d'analyser quelques problèmes théoriques dans l'étude des relations entre familles populaires et école, problèmes qui sont ceux que rencontre la sociologie dans l'étude des classes populaires et de leurs relations avec le monde dominant et les institutions. Il explore la possibilité de dépasser l'alternative entre une perspective strictement légitimiste qui tend à réduire les classes populaires et leurs pratiques au rapport de domination qui les aliène (hétéronomie) et la perspective relativiste qui les envisage dans une altérité radicale (autonomie) en occultant les rapports sociaux de domination. Il insiste sur l'ambivalence des logiques et des pratiques des familles populaire
Cortical fast-spiking parvalbumin interneurons enwrapped in the perineuronal net express the metallopeptidases Adamts8, Adamts15 and Neprilysin.
The in situ hybridization Allen Mouse Brain Atlas was mined for proteases expressed in the somatosensory cerebral cortex. Among the 480 genes coding for protease/peptidases, only four were found enriched in cortical interneurons: Reln coding for reelin; Adamts8 and Adamts15 belonging to the class of metzincin proteases involved in reshaping the perineuronal net (PNN) and Mme encoding for Neprilysin, the enzyme degrading amyloid β-peptides. The pattern of expression of metalloproteases (MPs) was analyzed by single-cell reverse transcriptase multiplex PCR after patch clamp and was compared with the expression of 10 canonical interneurons markers and 12 additional genes from the Allen Atlas. Clustering of these genes by K-means algorithm displays five distinct clusters. Among these five clusters, two fast-spiking interneuron clusters expressing the calcium-binding protein Pvalb were identified, one co-expressing Pvalb with Sst (PV-Sst) and another co-expressing Pvalb with three metallopeptidases Adamts8, Adamts15 and Mme (PV-MP). By using Wisteria floribunda agglutinin, a specific marker for PNN, PV-MP interneurons were found surrounded by PNN, whereas the ones expressing Sst, PV-Sst, were not
Intrinsically determined cell death of developing cortical interneurons
Cortical inhibitory circuits are formed by GABAergic interneurons, a cell population that originates far from the cerebral cortex in the embryonic ventral forebrain. Given their distant developmental origins, it is intriguing how the number of cortical interneurons is ultimately determined. One possibility, suggested by the neurotrophic hypothesis1-5, is that cortical interneurons are overproduced, and then following their migration into cortex, excess interneurons are eliminated through a competition for extrinsically derived trophic signals. Here we have characterized the developmental cell death of mouse cortical interneurons in vivo, in vitro, and following transplantation. We found that 40% of developing cortical interneurons were eliminated through Bax- (Bcl-2 associated X-) dependent apoptosis during postnatal life. When cultured in vitro or transplanted into the cortex, interneuron precursors died at a cellular age similar to that at which endogenous interneurons died during normal development. Remarkably, over transplant sizes that varied 200-fold, a constant fraction of the transplanted population underwent cell death. The death of transplanted neurons was not affected by the cell-autonomous disruption of TrkB (tropomyosin kinase receptor B), the main neurotrophin receptor expressed by central nervous system (CNS) neurons6-8. Transplantation expanded the cortical interneuron population by up to 35%, but the frequency of inhibitory synaptic events did not scale with the number of transplanted interneurons. Together, our findings indicate that interneuron cell death is intrinsically determined, either cell-autonomously, or through a population-autonomous competition for survival signals derived from other interneurons
Nesfatin-1/NUCB2 as a Potential New Element of Sleep Regulation in Rats.
STUDY OBJECTIVES: Millions suffer from sleep disorders that often accompany severe illnesses such as major depression; a leading psychiatric disorder characterized by appetite and rapid eye movement sleep (REMS) abnormalities. Melanin-concentrating hormone (MCH) and nesfatin-1/NUCB2 (nesfatin) are strongly co - expressed in the hypothalamus and are involved both in food intake regulation and depression. Since MCH was recognized earlier as a hypnogenic factor, we analyzed the potential role of nesfatin on vigilance. DESIGN: We subjected rats to a 72 h-long REMS deprivation using the classic flower pot method, followed by a 3 h-long 'rebound sleep'. Nesfatin mRNA and protein expressions as well as neuronal activity (Fos) were measured by quantitative in situ hybridization technique, ELISA and immunohistochemistry, respectively, in 'deprived' and 'rebound' groups, relative to controls sacrificed at the same time. We also analyzed electroencephalogram of rats treated by intracerebroventricularly administered nesfatin-1, or saline. RESULTS: REMS deprivation downregulated the expression of nesfatin (mRNA and protein), however, enhanced REMS during 'rebound' reversed this to control levels. Additionally, increased transcriptional activity (Fos) was demonstrated in nesfatin neurons during 'rebound'. Centrally administered nesfatin-1 at light on reduced REMS and intermediate stage of sleep, while increased passive wake for several hours and also caused a short-term increase in light slow wave sleep. CONCLUSIONS: The data designate nesfatin as a potential new factor in sleep regulation, which fact can also be relevant in the better understanding of the role of nesfatin in the pathomechanism of depression
Metal accumulation in tobacco expressing Arabidopsis halleri metal hyperaccumulation gene depends on external supply
Engineering enhanced transport of zinc to the aerial parts of plants is a major goal in bio-fortification. In Arabidopsis halleri, high constitutive expression of the AhHMA4 gene encoding a metal pump of the P1B-ATPase family is necessary for both Zn hyperaccumulation and the full extent of Zn and Cd hypertolerance that are characteristic of this species. In this study, an AhHMA4 cDNA was introduced into N. tabacum var. Xanthi for expression under the control of its endogenous A. halleri promoter known to confer high and cell-type specific expression levels in both A. halleri and the non-hyperaccumulator A. thaliana. The transgene was expressed at similar levels in both roots and shoots upon long-term exposure to low Zn, control, and increased Zn concentrations. A down-regulation of AhHMA4 transcript levels was detected with 10 μM Zn resupply to tobacco plants cultivated in low Zn concentrations. In general, a transcriptional regulation of AhHMA4 in tobacco contrasted with the constitutively high expression previously observed in A. halleri. Differences in root/shoot partitioning of Zn and Cd between transgenic lines and the wild type were strongly dependent on metal concentrations in the hydroponic medium. Under low Zn conditions, an increased Zn accumulation in the upper leaves in the AhHMA4-expressing lines was detected. Moreover, transgenic plants exposed to cadmium accumulated less metal than the wild type. Both modifications of zinc and cadmium accumulation are noteworthy outcomes from the biofortification perspective and healthy food production. Expression of AhHMA4 may be useful in crops grown on soils poor in Zn
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