2,040 research outputs found

    Biogeographical Evidence for the Grass (Poaceae) Species of Pleistocene Beringian Lowlands

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    Late Pleistocene Beringia had herb-dominated vegetation with abundant grasses (Poaceae), and it was inhabited by an impressive assemblage of large grazing mammals. This paper reconstructs the list of most probable late Pleistocene Beringian lowland grass species from biogeographical evidence. Late Pleistocene eolian sediments and buried soils indicate that large areas of the Beringian lowlands had nutrient-rich, silty soils that occurred over ice-rich permafrost but were generally not waterlogged. A list of likely grasses was compiled from all species that have been recorded on similar fine-grained, mesic-to-dry lowland soils (i.e., presumed refugia) and are distributed at least sporadically across the whole region today. Grasses from 13 genera met these criteria, including most of the taxa that have been identified as late Pleistocene fossils from the study area. Most of these grasses are high-latitude species of genera that are also common in temperate latitudes (e.g., Elymus, Festuca, and Poa). This diverse group of plants has a wide range of adaptations today, suggesting that grasses would have been available to occupy a variety of habitats through Pleistocene climatic fluctuations. Among these grasses are a number of highly productive forage species.La vĂ©gĂ©tation de la BĂ©ringie du PlĂ©istocĂšne supĂ©rieur Ă©tait dominĂ©e par des herbes abondantes (Poaceae). De plus, elle Ă©tait habitĂ©e par un assemblage impressionnant de gros mammifĂšres broutards. Dans cet article, nous dressons la liste des espĂšces vĂ©gĂ©tales des basses-terres les plus probables de la BĂ©ringie du PlĂ©istocĂšne supĂ©rieur Ă  partir d’observations biogĂ©ographiques. Les sĂ©diments Ă©oliens du PlĂ©istocĂšne supĂ©rieur et les sols enfouis laissent supposer que de vastes rĂ©gions des basses-terres de la BĂ©ringie avaient des sols limoneux riches en nutriments situĂ©s sur du pergĂ©lisol riche en glace, sans ĂȘtre gĂ©nĂ©ralement gorgĂ©s d’eau. La liste des herbes susceptibles de s’ĂȘtre retrouvĂ©es Ă  l’époque a Ă©tĂ© compilĂ©e Ă  partir de toutes les espĂšces qui ont Ă©tĂ© enregistrĂ©es sur des sols fins similaires de basses-terres allant de mĂ©soĂŻques Ă  secs (i.e., refuges naturels prĂ©sumĂ©s) et qui sont rĂ©parties, de maniĂšre tout au moins sporadique, dans toute la rĂ©gion aujourd’hui. Les herbes de 13 genres ont satisfait ces critĂšres, ce qui comprend la plupart des taxons qui ont Ă©tĂ© identifiĂ©s Ă  titre de fossiles du PlĂ©istocĂšne supĂ©rieur dans la rĂ©gion visĂ©e par l’étude. La plupart de ces herbes sont des espĂšces de genres se retrouvant en haute altitude qui sont Ă©galement en latitudes tempĂ©rĂ©es (comme Elymus, Festuca et Poa). De nos jours, ce groupe de vĂ©gĂ©taux divers a subi de nombreuses adaptations, ce qui laisse supposer que les herbes auraient occupĂ© une variĂ©tĂ© d’habitats pendant les fluctuations climatiques du PlĂ©istocĂšne. Parmi ces herbes, notons un certain nombre d’espĂšces fourragĂšres hautement productives

    Aspen biology, community classification, and management in the Blue Mountains

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    Quaking aspen (Populus tremuloides Michx.) is a valuable species that is declining in the Blue Mountains of northeastern Oregon. This publication is a compilation of over 20 years of aspen management experience by USDA Forest Service workers in the Blue Mountains. It includes a summary of aspen biology and occurrence in the Blue Mountains, and a discussion of aspen conservation and management techniques such as fencing, conifer removal, and artificial propagation. Local data on bird use of aspen stands, insects and diseases in aspen, and genetic studies of aspen are also included. An aspen community classification developed from over 200 sample plots is presented, with plant species composition and cover, environment and soils, and management considerations

    The natural history of spina bifida in children pilot project : Research protocol

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    Background: Population-based empirical information to inform health care professionals working with children with spina bifida currently is lacking. Spina bifida is a highly complex condition that not only affects mobility but many additional aspects of life. We have developed a pilot project that focuses on a broad range of domains: Surgeries, development and learning, nutrition and physical growth, mobility and functioning, general health, and family demographics. Specifically, we will: (1) explore the feasibility of identifying and recruiting participants using different recruitment sources, (2) test a multidisciplinary module to collect the data, (3) determine the utility of different methods of retrieving the data, and (4) summarize descriptive information on living with spina bifida. Objective: The overall objective of the project was to provide information for a future multistate prospective study on the natural history of spina bifida. Methods: Families with a child 3 to 6 years of age with a diagnosis of spina bifida were eligible for enrollment. Eligible families were identified through a US population-based tracking system for birth defects and from a local spina bifida clinic. Results: This is an ongoing project with first results expected in 2013. Conclusions: This project, and the planned multistate follow-up project, will provide information both to health care professionals experienced in providing care to patients with spina bifida, and to those who have yet to work with this population. The long-term purpose of this project is to increase the knowledge about growing up with spina bifida and to guide health care practices by prospectively studying a cohort of children born with this condition

    Rigorous Computational and Experimental Investigations on MDM2/MDMX-Targeted Linear and Macrocyclic Peptides

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    There is interest in peptide drug design, especially for targeting intracellular protein–protein interactions. Therefore, the experimental validation of a computational platform for enabling peptide drug design is of interest. Here, we describe our peptide drug design platform (CMDInventus) and demonstrate its use in modeling and predicting the structural and binding aspects of diverse peptides that interact with oncology targets MDM2/MDMX in comparison to both retrospective (pre-prediction) and prospective (post-prediction) data. In the retrospective study, CMDInventus modules (CMDpeptide, CMDboltzmann, CMDescore and CMDyscore) were used to accurately reproduce structural and binding data across multiple MDM2/MDMX data sets. In the prospective study, CMDescore, CMDyscore and CMDboltzmann were used to accurately predict binding affinities for an Ala-scan of the stapled α-helical peptide ATSP-7041. Remarkably, CMDboltzmann was used to accurately predict the results of a novel D-amino acid scan of ATSP-7041. Our investigations rigorously validate CMDInventus and support its utility for enabling peptide drug design

    Parkinson's disease biomarkers: perspective from the NINDS Parkinson's Disease Biomarkers Program

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    Biomarkers for Parkinson's disease (PD) diagnosis, prognostication and clinical trial cohort selection are an urgent need. While many promising markers have been discovered through the National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) and other mechanisms, no single PD marker or set of markers are ready for clinical use. Here we discuss the current state of biomarker discovery for platforms relevant to PDBP. We discuss the role of the PDBP in PD biomarker identification and present guidelines to facilitate their development. These guidelines include: harmonizing procedures for biofluid acquisition and clinical assessments, replication of the most promising biomarkers, support and encouragement of publications that report negative findings, longitudinal follow-up of current cohorts including the PDBP, testing of wearable technologies to capture readouts between study visits and development of recently diagnosed (de novo) cohorts to foster identification of the earliest markers of disease onset

    Intraspecific Correlations of Basal and Maximal Metabolic Rates in Birds and the Aerobic Capacity Model for the Evolution of Endothermy

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    The underlying assumption of the aerobic capacity model for the evolution of endothermy is that basal (BMR) and maximal aerobic metabolic rates are phenotypically linked. However, because BMR is largely a function of central organs whereas maximal metabolic output is largely a function of skeletal muscles, the mechanistic underpinnings for their linkage are not obvious. Interspecific studies in birds generally support a phenotypic correlation between BMR and maximal metabolic output. If the aerobic capacity model is valid, these phenotypic correlations should also extend to intraspecific comparisons. We measured BMR, Msum (maximum thermoregulatory metabolic rate) and MMR (maximum exercise metabolic rate in a hop-flutter chamber) in winter for dark-eyed juncos (Junco hyemalis), American goldfinches (Carduelis tristis; Msum and MMR only), and black-capped chickadees (Poecile atricapillus; BMR and Msum only) and examined correlations among these variables. We also measured BMR and Msum in individual house sparrows (Passer domesticus) in both summer, winter and spring. For both raw metabolic rates and residuals from allometric regressions, BMR was not significantly correlated with either Msum or MMR in juncos. Moreover, no significant correlation between Msum and MMR or their mass-independent residuals occurred for juncos or goldfinches. Raw BMR and Msum were significantly positively correlated for black-capped chickadees and house sparrows, but mass-independent residuals of BMR and Msum were not. These data suggest that central organ and exercise organ metabolic levels are not inextricably linked and that muscular capacities for exercise and shivering do not necessarily vary in tandem in individual birds. Why intraspecific and interspecific avian studies show differing results and the significance of these differences to the aerobic capacity model are unknown, and resolution of these questions will require additional studies of potential mechanistic links between minimal and maximal metabolic output

    Maternal therapy with Ad.VEGF-A165 increases fetal weight at term in a guinea pig model of fetal growth restriction

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    OBJECTIVES: We have demonstrated that transient uterine artery VEGF overexpression improves fetal growth in growth restricted sheep pregnancy. We tested this hypothesis in guinea pig pregnancies, where placental physiology more closely resembles that in humans. METHOD: Virgin guinea pigs were nutrient restricted peri-conceptually to create fetal growth restriction (FGR). At day 29-36 (term=65days) at laparotomy Ad.VEGF-A165 or Ad.LacZ (1x1010vp) were applied externally to the uterine circulation using a thermosensitive gel. Dams were sacrificed after 3-8 days or at term. Pups were weighed and tissues sampled for vector spread, VEGF expression and its downstream effects. RESULTS: Ad.VEGF-A165 significantly increased fetal weight at term (88.01±13.36g, n=26) compared to control Ad.LacZ treatment (85.52±13.00g, n=19, p=0.028). Brain, liver, lung weight and crown rump length were significantly larger 3-8 days post-administration, VEGF expression was demonstrated by ELISA and confirmed by immunohistochemistry in transduced tissues. RT-PCR of term samples confirmed vector transduction in target tissues, but the transgene was undetectable in fetal samples. Tissue histological analysis and blood biochemistry/haematological examination was normal. Uterine arteries from Ad.VEGF-A165-treated dams relaxed more completely than those from Ad.LacZ treated dams. CONCLUSIONS: Maternal uterine artery Ad.VEGF-A165 increases fetal growth velocity and term fetal weight in growth restricted guinea pig pregnancy

    Exercise repetition rate measured with simple sensors at home can be used to estimate Upper Extremity Fugl-Meyer score after stroke

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    IntroductionIt would be valuable if home-based rehabilitation training technologies could automatically assess arm impairment after stroke. Here, we tested whether a simple measure—the repetition rate (or “rep rate”) when performing specific exercises as measured with simple sensors—can be used to estimate Upper Extremity Fugl-Meyer (UEFM) score.Methods41 individuals with arm impairment after stroke performed 12 sensor-guided exercises under therapist supervision using a commercial sensor system comprised of two pucks that use force and motion sensing to measure the start and end of each exercise repetition. 14 of these participants then used the system at home for three weeks.ResultsUsing linear regression, UEFM score was well estimated using the rep rate of one forward-reaching exercise from the set of 12 exercises (r2 = 0.75); this exercise required participants to alternately tap pucks spaced about 20 cm apart (one proximal, one distal) on a table in front of them. UEFM score was even better predicted using an exponential model and forward-reaching rep rate (Leave One Out Cross Validation (LOOCV) r2 = 0.83). We also tested the ability of a nonlinear, multivariate model (a regression tree) to predict UEFM, but such a model did not improve prediction (LOOCV r2 = 0.72). However, the optimal decision tree also used the forward-reaching task along with a pinch grip task to subdivide more and less impaired patients in a way consistent with clinical intuition. At home, rep rate for the forward-reaching exercise well predicted UEFM score using an exponential model (LOOCV r2 = 0.69), but only after we re-estimated coefficients using the home data.DiscussionThese results show how a simple measure—exercise rep rate measured with simple sensors—can be used to infer an arm impairment score and suggest that prediction models should be tuned separately for the clinic and home environments

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Analysis of potential systematics

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    We analyze the density field of galaxies observed by the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in the SDSS Data Release Nine (DR9). DR9 includes spectroscopic redshifts for over 400,000 galaxies spread over a footprint of 3,275 deg^2. We identify, characterize, and mitigate the impact of sources of systematic uncertainty on large-scale clustering measurements, both for angular moments of the redshift-space correlation function and the spherically averaged power spectrum, P(k), in order to ensure that robust cosmological constraints will be obtained from these data. A correlation between the projected density of stars and the higher redshift (0.43 < z < 0.7) galaxy sample (the `CMASS' sample) due to imaging systematics imparts a systematic error that is larger than the statistical error of the clustering measurements at scales s > 120h^-1Mpc or k < 0.01hMpc^-1. We find that these errors can be ameliorated by weighting galaxies based on their surface brightness and the local stellar density. We use mock galaxy catalogs that simulate the CMASS selection function to determine that randomly selecting galaxy redshifts in order to simulate the radial selection function of a random sample imparts the least systematic error on correlation function measurements and that this systematic error is negligible for the spherically averaged correlation function. The methods we recommend for the calculation of clustering measurements using the CMASS sample are adopted in companion papers that locate the position of the baryon acoustic oscillation feature (Anderson et al. 2012), constrain cosmological models using the full shape of the correlation function (Sanchez et al. 2012), and measure the rate of structure growth (Reid et al. 2012). (abridged)Comment: Matches version accepted by MNRAS. Clarifications and references have been added. See companion papers that share the "The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey:" titl
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