402 research outputs found

    Who bullies whom at a garden feeder? Interspecific agonistic interactions of small passerines during a cold winter

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    Interspecific agonistic interactions are important selective factors for maintaining ecological niches of different species, but their outcome is difficult to predict a priori. Here, we examined the direction and intensity of interspecific interactions in an assemblage of small passerines at a garden feeder, focussing on three finch species of various body sizes. We found that large and mediumsized birds usually initiated and won agonistic interactions with smaller species. Also, the frequency of fights increased with decreasing differences in body size between the participants. Finally, the probability of engaging in a fight increased with the number of birds at the feeder

    The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam on board Curiosity

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    The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. From ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations reveals that the mean K2O abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater

    Extragalactic Results from the Infrared Space Observatory

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    More than a decade ago the IRAS satellite opened the realm of external galaxies for studies in the 10 to 100 micron band and discovered emission from tens of thousands of normal and active galaxies. With the 1995-1998 mission of the Infrared Space Observatory the next major steps in extragalactic infrared astronomy became possible: detailed imaging, spectroscopy and spectro-photometry of many galaxies detected by IRAS, as well as deep surveys in the mid- and far- IR. The spectroscopic data reveal a wealth of detail about the nature of the energy source(s) and about the physical conditions in galaxies. ISO's surveys for the first time explore the infrared emission of distant, high-redshift galaxies. ISO's main theme in extragalactic astronomy is the role of star formation in the activity and evolution of galaxies.Comment: 106 pages, including 17 figures. Ann.Rev.Astron.Astrophys. (in press), a gzip'd pdf file (667kB) is also available at http://www.mpe.mpg.de/www_ir/preprint/annrev2000.pdf.g

    Malnutrition Has No Effect on the Timing of Human Tooth Formation

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    The effect of nutrition on the timing of human tooth formation is poorly understood. Delays and advancements in dental maturation have all been reported as well as no effect. We investigated the effect of severe malnutrition on the timing of human tooth formation in a large representative sample of North Sudanese children. The sample (1102 males, 1013 females) consisted of stratified randomly selected healthy individuals in Khartoum, Sudan, aged 2-22 years using a cross-sectional design following the STROBE statement. Nutritional status was defined using WHO criteria of height and weight. Body mass index Z-scores and height for age Z-scores of ≤-2 (cut-off) were used to identify the malnourished group (N = 474) while the normal was defined by Z-scores of ≥0 (N = 799). Clinical and radiographic examination of individuals, with known ages of birth was performed including height and weight measurements. Mandibular left permanent teeth were assessed using eight crown and seven root established tooth formation stages. Mean age at entry and mean age within tooth stages were calculated for each available tooth stage in each group and compared using a t-test. Results show the mean age at entry and mean age within tooth stages were not significantly different between groups affected by severe malnutrition and normal children (p>0.05). This remarkable finding was evident across the span of dental development. We demonstrate that there is little measurable effect of sustained malnutrition on the average timing of tooth formation. This noteworthy finding supports the notion that teeth have substantial biological stability and are insulated from extreme nutritional conditions compared to other maturing body systems

    Precipitation drives global variation in natural selection

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    Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation - natural selection - are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By showing that selection was influenced by climate variation, our results indicate that climate change may cause widespread alterations in selection regimes, potentially shifting evolutionary trajectories at a global scale

    Evaporative evolution of a Na–Cl–NO(3)–K–Ca–SO(4)–Mg–Si brine at 95°C: Experiments and modeling relevant to Yucca Mountain, Nevada

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    A synthetic Topopah Spring Tuff water representative of one type of pore water at Yucca Mountain, NV was evaporated at 95°C in a series of experiments to determine the geochemical controls for brines that may form on, and possibly impact upon the long-term integrity of waste containers and drip shields at the designated high-level, nuclear-waste repository. Solution chemistry, condensed vapor chemistry, and precipitate mineralogy were used to identify important chemical divides and to validate geochemical calculations of evaporating water chemistry using a high temperature Pitzer thermodynamic database. The water evolved toward a complex "sulfate type" brine that contained about 45 mol % Na, 40 mol % Cl, 9 mol % NO(3), 5 mol % K, and less than 1 mol % each of SO(4), Ca, Mg, ∑CO(2)(aq), F, and Si. All measured ions in the condensed vapor phase were below detection limits. The mineral precipitates identified were halite, anhydrite, bassanite, niter, and nitratine. Trends in the solution composition and identification of CaSO(4 )solids suggest that fluorite, carbonate, sulfate, and magnesium-silicate precipitation control the aqueous solution composition of sulfate type waters by removing fluoride, calcium, and magnesium during the early stages of evaporation. In most cases, the high temperature Pitzer database, used by EQ3/6 geochemical code, sufficiently predicts water composition and mineral precipitation during evaporation. Predicted solution compositions are generally within a factor of 2 of the experimental values. The model predicts that sepiolite, bassanite, amorphous silica, calcite, halite, and brucite are the solubility controlling mineral phases

    Synthetic microparticles conjugated with VEGF165 improve the survival of endothelial progenitor cells via microRNA-17 inhibition

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    Several cell-based therapies are under pre-clinical and clinical evaluation for the treatment of ischemic diseases. Poor survival and vascular engraftment rates of transplanted cells force them to work mainly via time-limited paracrine actions. Although several approaches, including the use of soluble vascular endothelial growth factor (sVEGF)-VEGF165, have been developed in the last 10 years to enhance cell survival, they showed limited efficacy. Here, we report a pro-survival approach based on VEGF-immobilized microparticles (VEGF-MPs). VEGF-MPs prolong VEGFR-2 and Akt phosphorylation in cord blood-derived late outgrowth endothelial progenitor cells (OEPCs). In vivo, OEPC aggregates containing VEGF-MPs show higher survival than those treated with sVEGF. Additionally, VEGF-MPs decrease miR-17 expression in OEPCs, thus increasing the expression of its target genes CDKN1A and ZNF652. The therapeutic effect of OEPCs is improved in vivo by inhibiting miR-17. Overall, our data show an experimental approach to improve therapeutic efficacy of proangiogenic cells for the treatment of ischemic diseases.Soluble vascular endothelial growth factor (VEGF) enhances vascular engraftment of transplanted cells but the efficacy is low. Here, the authors show that VEGF-immobilized microparticles prolong survival of endothelial progenitors in vitro and in vivo by downregulating miR17 and upregulating CDKN1A and ZNF652

    Feasibility and reliability of frailty assessment in the critically ill: a systematic review

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    Background. For healthcare systems, an ageing population poses challenges in the delivery of equitable and effective care. Frailty assessment has the potential to improve care in the intensive care setting, but applying assessment tools in critical illness may be problematic. The aim of this systematic review was to evaluate evidence for the feasibility and reliability of frailty assessment in critical care. Methods. Our primary search was conducted in Medline, Medline In-process, EMBASE, CINAHL, PsycINFO, AMED, Cochrane Database of Systematic Reviews, and Web of Science (January 2001 to October 2017). We included observational studies reporting data on feasibility and reliability of frailty assessment in critical care setting in patients 16 years and older. Feasibility was assessed in terms of timing of evaluation, the background, training and expertise required for assessors, and reliance upon proxy input. Reliability was assessed in terms of inter-rater reliability. Results. Data from 11 study publications are included, representing eight study cohorts and 7761 patients. Proxy involvement in frailty assessment ranged from 58- 100%. Feasibility data were not well-reported overall, but the exclusion rate due to lack of proxy availability ranged from 0 to 45%, the highest rate observed where family involvement was mandatory and the assessment tool relatively complex (Frailty Index, FI). Conventional elements of Frailty Phenotype (FP) assessment required modification prior to use in two studies. Clinical staff tended to use a simple judgement-based tool, the Clinical Frailty Scale (CFS). Inter-rater reliability was reported in one study using the CFS and although a good level of agreement was observed between clinician assessments, this was a small and single centre study. Conclusion. Though of unproven reliability in the critically ill, CFS was the tool used most widely by critical care clinical staff. Conventional FP assessment required modification for general application in critical care, and a FI-based assessment may be difficult to deliver by the critical care team on a routine basis. There is a high reliance on proxies for frailty assessment, and the reliability of frailty assessment tools in critical care needs further evaluation. PROSPERO CRD42016052073

    Evaluation of the function and quality of life of patients submitted to girdlestone's resection arthroplasty

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    OBJECTIVES: To evaluate function and quality of life of patients submitted to Girdlestone's arthroplasty, and to compare outcomes between unilateral Girdlestone's group with the group with contralateral total hip prosthesis. METHODS: Cross-sectional study where 9 patients were evaluated with unilateral Girdlestone's and 3 with Girdlestone's in one hip and contralateral total hip prosthesis. The evaluation consisted in filling in a generic questionnaire on quality of life SF-36 and a specific questionnaire for hip function Harris Hip Score (HHS). The comparison between groups was made by using the Student's t-test and the Fisher's test. RESULTS: The patients of the unilateral Girdlestone's group presented a higher number of SF-36 domains classified as high, although 77.8% of these showed poor results on the HHS. All patients had a leg-length discrepancy and positive Trendelenburg's test, which led to limping gait in 11 of 12 patients evaluated. Of these, only 6 underwent physiotherapy after surgery. CONCLUSION: Girdlestone's postoperative quality of life and function in a Brazilian population still requires further studies, because these outcomes are indicative of study variables' behavior and cannot be regarded as definite.OBJETIVOS: Avaliar a função e a qualidade de vida dos pacientes pós-artroplastia de Girdlestone e comparar os resultados entre os grupos Girdlestone unilateral e o grupo com prótese total de quadril contralateral. MÉTODOS: estudo transversal no qual foram avaliados 9 pacientes com Girdlestone unilateral e 3 com Girdlestone em um quadril e prótese total no quadril contralateral. A avaliação constitui-se em aplicar o questionário genérico de qualidade de vida SF-36 e um questionário funcional específico para o quadril, Harris Hip Score (HHS). A comparação dos grupos foi realizada usando-se o teste t- Student e o teste de Fisher. RESULTADOS: Os pacientes do grupo Girdlestone unilateral apresentaram maior quantidade de domínios do SF-36 classificados como elevados, embora 77,8% destes tenham obtido resultados ruins no HHS. Todos os pacientes apresentaram o teste de Trendelenburg positivo e discrepância de membros, o que levou à marcha claudicante em 11 dos 12 pacientes avaliados. Destes, apenas 6 submeteram-se a fisioterapia pós-operatória. CONCLUSÃO: A qualidade de vida e a função pós-operatória de Girdlestone, na população brasileira, ainda necessita ser mais pesquisada, pois estes resultados são indicações do comportamento das variáveis de estudo e não podem ser consideradas encerradas.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Ortopedia e TraumatologiaUNIFESP-EPM DOTUNIFESP, EPM, Depto. de Ortopedia e TraumatologiaUNIFESP, EPM DOTSciEL
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