2,745 research outputs found

    Population study of Pyxis arachnoides brygooi (Vuillemin & Domergue, 1972) in the area surrounding the Village des Tortues, Ifaty - Mangily, southwest Madagascar

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    The Madagascar spider tortoise (Pyxis arachnoides spp.) is faced with the threat of habitat destruction as well as the international pet trade. Habitat requirements and population structure of this species are largely unknown. Detailed studies have so far concentrated on the subspecies Pyxis arachnoides arachnoides. The present study surveyed a population of the western subspecies Pyxis arachnoides brygooi during the wet season from February to April 2008. The survey was carried out in the forest of Ifaty - Mangily, 20 km north of Toliara, and supported by a local tortoise centre, the Village des Tortues. Population densities were estimated from transect counts and plot surveys; they range from 0.33 to 1.72 animals per hectare. Both sexes were evenly represented in the field during the research period. Three individuals of the subspecies Pyxis arachnoides arachnoides were detected during this field survey. Their presence might be due to a transitional zone of both subspecies in the area of research. La tortue araignée de Madagascar, Pyxis arachnoides spp. est menacée par la destruction de son habitat naturel et par les collectes illicites de spécimens destinés au commerce. Les besoins écologiques et la structure de la population naturelle de cette espèce sont encore peu connus. Jusqu’à présent, la plupart des études effectuées se sont concentrées sur la sous - espèce nominative Pyxis arachnoides arachnoides. La présente étude a été réalisée dans la partie sud - ouest de Madagascar, dans la forêt d’Ifaty - Mangily, à 20 kilomètres au nord de Toliara pendant la saison humide, entre février et avril 2008 sur une population de Pyxis arachnoides brygooi. Les travaux sur le terrain ont été effectués en coopération avec le « Village des Tortues » qui est un centre d’élevage et de sauvegarde des tortues confisquées par les autorités malgaches. La densité de la population étudiée sur le terrain varie de 0,33 à 1,72 individus par hectare ; cette estimation a été faite en se basant sur le suivi par transects et de parcelles d’une superficie d’un hectare. Le sexe ratio de tues ayant une longueur de carapace inférieure à 90 mm ont été classées en tant que juvéniles ou sub - adultes dans la mesure où ces individus ont été difficiles à sexer. La taille des individus recensés pendant cette étude varie de 37 à 122 millimètres et les femelles étaient en moyenne plus lourdes que les mâles. La présence des trois individus de Pyxis arachnoides arachnoides recensés dans la zone de recherche pourrait résulter d’une zone de transition entre les différentes sous - espèces

    Continuity of Care During End of Life: An Evolutionary Concept Analysis

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    PURPOSE: The purpose of this study was to clarify the concept of continuity of care during the end of life with a focus on the patient’s perspective. METHODS: Rodgers’ method of evolutionary concept analysis was used. The analysis was based on literature published in English in the databases Cumulative Index for Nursing and Allied Health Literature, Medline, and PsycINFO. FINDINGS: Analysis revealed that the continuity at life’s end is a dynamic process that depends on the interaction among patients, families, and providers, and is strictly interwoven with the patient’s time perception. CONCLUSION: This analysis showed the complexities surrounding the patient’s experience of continuity at life’s end. IMPLICATION FOR NURSING: Nurses can benefit from a deeper understanding of the patient’s experience, both theoretically and in practice

    The FALCON concept: multi-object spectroscopy combined with MCAO in near-IR

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    A large fraction of the present-day stellar mass was formed between z=0.5 and z~3 and our understanding of the formation mechanisms at work at these epochs requires both high spatial and high spectral resolution: one shall simultaneously} obtain images of objects with typical sizes as small as 1-2kpc(~0''.1), while achieving 20-50 km/s (R >= 5000) spectral resolution. The obvious instrumental solution to adopt in order to tackle the science goal is therefore a combination of multi-object 3D spectrograph with multi-conjugate adaptive optics in large fields. A partial, but still competitive correction shall be prefered, over a much wider field of view. This can be done by estimating the turbulent volume from sets of natural guide stars, by optimizing the correction to several and discrete small areas of few arcsec2 selected in a large field (Nasmyth field of 25 arcmin) and by correcting up to the 6th, and eventually, up to the 60th Zernike modes. Simulations on real extragalactic fields, show that for most sources (>80%), the recovered resolution could reach 0".15-0".25 in the J and H bands. Detection of point-like objects is improved by factors from 3 to >10, when compared with an instrument without adaptive correction. The proposed instrument concept, FALCON, is equiped with deployable mini-integral field units (IFUs), achieving spectral resolutions between R=5000 and 20000. Its multiplex capability, combined with high spatial and spectral resolution characteristics, is a natural ground based complement to the next generation of space telescopes.Comment: ESO Workshop Proceedings: Scientific Drivers for ESO Future VLT/VLTI Instrumentation, 10 pages and 5 figure

    A cross-national study on the antecedents of work–life balance from the fit and balance perspective

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    Drawing on the perceived work–family fit and balance perspective, this study investigates demands and resources as antecedents of work–life balance (WLB) across four countries (New Zealand, France, Italy and Spain), so as to provide empirical cross-national evidence. Using structural equation modelling analysis on a sample of 870 full time employees, we found that work demands, hours worked and family demands were negatively related to WLB, while job autonomy and supervisor support were positively related to WLB. We also found evidence that resources (job autonomy and supervisor support) moderated the relationships between demands and work–life balance, with high resources consistently buffering any detrimental influence of demands on WLB. Furthermore, our study identified additional predictors of WLB that were unique to some national contexts. For example, in France and Italy, overtime hours worked were negatively associated with WLB, while parental status was positively associated with WLB. Overall, the implications for theory and practice are discussed.Peer ReviewedPostprint (author's final draft

    Negative and positive selection of antigen-specific cytotoxic T lymphocytes affected by the α3 domain of MHC I molecules

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    THE α1 and α2 domains of major histocompatibility complex (MHC) class I molecules function in the binding and presentation of foreign peptides to the T-cell antigen receptor and control both negative and positive selection of the T-cell repertoire. Although the α3 domain of class I is not involved in peptide binding, it does interact with the T-cell accessory molecule, CDS. CDS is important in the selection of T cells as anti-CDS antibody injected into perinatal mice interfers with this process. We previously used a hybrid class I molecule with the α1/α2 domains from L^d and the α3 domain from Q7^b and showed that this molecule binds an L^d-restricted peptide but does not interact with CD8-dependent cytotoxic T lymphocytes. Expression of this molecule in transgenic mice fails to negatively select a subpopulation of anti-L^d cytotoxic T lymphocytes. In addition, positive selection of virus-specific L^d-restricted cytotoxic T lymphocytes does not occur. We conclude that besides the α1/α2 domains of class I, the α3 domain plays an important part in both positive and negative selection of antigen-specific cells

    Rapid ascent of rhyolitic magma at Chaitén volcano, Chile

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    International audienceAlthough rhyolite magma has fuelled some of the Earth's largest explosive volcanic eruptions, our understanding of these events is incomplete due to the previous lack of direct observation of these eruptions. On 1 May 2008, Chaitén volcano in Chile erupted rhyolite magma unexpectedly and explosively. Here, petrological and experimental data are presented that indicate that the hydrous rhyolite magma at Chaitén ascended very rapidly from storage depth to near-surface, with velocities of the order of one metre per second

    Hyperspectral Computed Tomographic Imaging Spectroscopy of Vascular Oxygen Gradients in the Rabbit Retina In Vivo

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    Diagnosis of retinal vascular diseases depends on ophthalmoscopic findings that most often occur after severe visual loss (as in vein occlusions) or chronic changes that are irreversible (as in diabetic retinopathy). Despite recent advances, diagnostic imaging currently reveals very little about the vascular function and local oxygen delivery. One potentially useful measure of vascular function is measurement of hemoglobin oxygen content. In this paper, we demonstrate a novel method of accurately, rapidly and easily measuring oxygen saturation within retinal vessels using in vivo imaging spectroscopy. This method uses a commercially available fundus camera coupled to two-dimensional diffracting optics that scatter the incident light onto a focal plane array in a calibrated pattern. Computed tomographic algorithms are used to reconstruct the diffracted spectral patterns into wavelength components of the original image. In this paper the spectral components of oxy- and deoxyhemoglobin are analyzed from the vessels within the image. Up to 76 spectral measurements can be made in only a few milliseconds and used to quantify the oxygen saturation within the retinal vessels over a 10–15 degree field. The method described here can acquire 10-fold more spectral data in much less time than conventional oximetry systems (while utilizing the commonly accepted fundus camera platform). Application of this method to animal models of retinal vascular disease and clinical subjects will provide useful and novel information about retinal vascular disease and physiology

    Input-modulation as an alternative to conventional learning strategies

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    Animals use various strategies for learning stimulus-reward associations. Computational methods that mimic animal behaviour most commonly interpret learning as a high level phenomenon, in which the pairing of stimulus and reward leads to plastic changes in the final output layers where action selection takes place. Here, we present an alternative input-modulation strategy for forming simple stimulus-response associations based on reward. Our model is motivated by experimental evidence on modulation of early brain regions by reward signalling in the honeybee. The model can successfully discriminate dissimilar odours and generalise across similar odours, like bees do. In the most simplified connectionist description, the new input- modulation learning is shown to be asymptotically equivalent to the standard perceptron

    Investigation of the presence of human or bovine respiratory syncytial virus in the lungs of mink (Neovison vison) with hemorrhagic pneumonia due to Pseudomonas aeruginosa

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    <p>Abstract</p> <p>Background</p> <p>Hemorrhagic pneumonia is a disease of farmed mink (<it>Neovison vison</it>) caused by <it>Pseudomonas aeruginosa</it>. The disease is highly seasonal in Danish mink with outbreaks occurring almost exclusively in the autumn. Human respiratory syncytial virus (RSV) has been shown to augment infection with <it>P. aeruginosa</it> in mice and to promote adhesion of <it>P. aeruginosa</it> to human respiratory cells.</p> <p>Findings</p> <p>We tested 50 lung specimens from mink with hemorrhagic pneumonia for bovine RSV by reverse transcriptase polymerase chain reaction (PCR) and for human RSV by a commercial real-time PCR. RSV was not found.</p> <p>Conclusions</p> <p>This study indicates that human and bovine RSV is not a major co-factor for development of hemorrhagic pneumonia in Danish mink.</p

    Genome Wide Transcriptome Analysis of Dendritic Cells Identifies Genes with Altered Expression in Psoriasis

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    Activation of dendritic cells by different pathogens induces the secretion of proinflammatory mediators resulting in local inflammation. Importantly, innate immunity must be properly controlled, as its continuous activation leads to the development of chronic inflammatory diseases such as psoriasis. Lipopolysaccharide (LPS) or peptidoglycan (PGN) induced tolerance, a phenomenon of transient unresponsiveness of cells to repeated or prolonged stimulation, proved valuable model for the study of chronic inflammation. Thus, the aim of this study was the identification of the transcriptional diversity of primary human immature dendritic cells (iDCs) upon PGN induced tolerance. Using SAGESeq approach, a tag-based transcriptome sequencing method, we investigated gene expression changes of primary human iDCs upon stimulation or restimulation with Staphylococcus aureus derived PGN, a widely used TLR2 ligand. Based on the expression pattern of the altered genes, we identified non-tolerizeable and tolerizeable genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (Kegg) analysis showed marked enrichment of immune-, cell cycle- and apoptosis related genes. In parallel to the marked induction of proinflammatory mediators, negative feedback regulators of innate immunity, such as TNFAIP3, TNFAIP8, Tyro3 and Mer are markedly downregulated in tolerant cells. We also demonstrate, that the expression pattern of TNFAIP3 and TNFAIP8 is altered in both lesional, and non-lesional skin of psoriatic patients. Finally, we show that pretreatment of immature dendritic cells with anti-TNF-α inhibits the expression of IL-6 and CCL1 in tolerant iDCs and partially releases the suppression of TNFAIP8. Our findings suggest that after PGN stimulation/restimulation the host cell utilizes different mechanisms in order to maintain critical balance between inflammation and tolerance. Importantly, the transcriptome sequencing of stimulated/restimulated iDCs identified numerous genes with altered expression to date not associated with role in chronic inflammation, underlying the relevance of our in vitro model for further characterization of IFNprimed iDCs
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