2,433 research outputs found

    Relationship of phenotypic variation and genetic admixture in the Saltmarsh–Nelson\u27s sparrow hybrid zone

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    Hybridization is influential in shaping species\u27 dynamics and has many evolutionary and conservation implications. Identification of hybrid individuals typically relies on morphological data, but the assumption that hybrids express intermediate traits is not always valid, because of complex patterns of introgression and selection. We characterized phenotypic and genotypic variation across a hybrid zone between 2 tidal-marsh birds, the Saltmarsh Sparrow (Ammodramus caudacutus) and Nelson\u27s Sparrow (A. nelsoni) (n = 290), and we sought to identify morphological traits that could be used to classify admixed individuals. Sparrows were sampled from a total of 34 marshes, including 23 sympatric and 11 putatively allopatric marshes. Each individual was scored at 13 plumage traits, and standard morphometric data were collected. We used genotyping analysis at 24 microsatellite loci to categorize individuals into genotypic classes of pure, F1–F2, or backcrossed. Genetic data revealed that 52% of individuals sampled along the geographic transect were of mixed ancestry, and the majority of these were backcrossed. Traits related to the definition of plumage features (streaking, crown, and face) showed less overlap between genotypic classes than traits related to the amount or color of plumage features. Although morphological data performed well in distinguishing between the 2 taxa, pure and backcrossed individuals of each parental type could not be distinguished because of substantial overlap in plumage and morphology. We conclude that the discrimination of pure and hybrid individuals is not possible in the absence of genetic data. Our results have implications for conservation of pure populations, as extensive backcrossing throughout the hybrid zone may present challenges for monitoring pure species identified by morphology alone

    Star Clusters in Virgo and Fornax Dwarf Irregular Galaxies

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    We present the results of a search for clusters in dwarf irregular galaxies in the Virgo and Fornax Cluster using HST WFPC2 snapshot data. The galaxy sample includes 28 galaxies, 11 of which are confirmed members of the Virgo and Fornax clusters. In the 11 confirmed members, we detect 237 cluster candidates and determine their V magnitudes, V-I colors and core radii. After statistical subtraction of background galaxies and foreground stars, most of the cluster candidates have V-I colors of -0.2 and 1.4, V magnitudes lying between 20 and 25th magnitude and core radii between 0 and 6 pc. Using H-alpha observations, we find that 26% of the blue cluster candidates are most likely HII regions. The rest of the cluster candidates are most likely massive (>10^4 Msol) young and old clusters. A comparison between the red cluster candidates in our sample and the Milky Way globular clusters shows that they have similar luminosity distributions, but that the red cluster candidates typically have larger core radii. Assuming that the red cluster candidates are in fact globular clusters, we derive specific frequencies (S_N) ranging from ~0-9 for the galaxies. Although the values are uncertain, seven of the galaxies appear to have specific frequencies greater than 2. These values are more typical of ellipticals and nucleated dwarf ellipticals than they are of spirals or Local Group dwarf irregulars.Comment: 46 pages, 14 figures, 3 tables, accepted by AJ. Higher quality PS version of entire paper available at http://www.astro.washington.edu/seth/dirr_gcs.htm

    RIPK3 restricts viral pathogenesis via cell death-independent neuroinflammation

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    Receptor-interacting protein kinase-3 (RIPK3) is an activator of necroptotic cell death, but recent work has implicated additional roles for RIPK3 in inflammatory signaling independent of cell death. However, while necroptosis has been shown to contribute to antiviral immunity, death-independent roles for RIPK3 in host defense have not been demonstrated. Using a mouse model of West Nile virus (WNV) encephalitis, we show that RIPK3 restricts WNV pathogenesis independently of cell death. Ripk3(-/-) mice exhibited enhanced mortality compared to wild-type (WT) controls, while mice lacking the necroptotic effector MLKL, or both MLKL and caspase-8, were unaffected. The enhanced susceptibility of Ripk3(-/-) mice arose from suppressed neuronal chemokine expression and decreased central nervous system (CNS) recruitment of T lymphocytes and inflammatory myeloid cells, while peripheral immunity remained intact. These data identify pleiotropic functions for RIPK3 in the restriction of viral pathogenesis and implicate RIPK3 as a key coordinator of immune responses within the CNS

    Comparison of Clinician Suspicion Versus a Clinical Prediction Rule in Identifying Children at Risk for Intra‐abdominal Injuries After Blunt Torso Trauma

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    ObjectivesEmergency department (ED) identification and radiographic evaluation of children with intra‐abdominal injuries who need acute intervention can be challenging. To date, it is unclear if a clinical prediction rule is superior to unstructured clinician judgment in identifying these children. The objective of this study was to compare the test characteristics of clinician suspicion with a derived clinical prediction rule to identify children at risk of intra‐abdominal injuries undergoing acute intervention following blunt torso trauma.MethodsThis was a planned subanalysis of a prospective, multicenter observational study of children (50% prior to knowledge of abdominal computed tomography (CT) scanning (if performed). Intra‐abdominal injuries undergoing acute intervention were defined by a therapeutic laparotomy, angiographic embolization, blood transfusion for abdominal hemorrhage, or intravenous fluid administration for 2 or more days in those with pancreatic or gastrointestinal injuries. Patients were considered to be positive for clinician suspicion if suspicion was documented as ≥1%. Suspicion ≥ 1% was compared to the presence of any variable in the prediction rule for identifying children with intra‐abdominal injuries undergoing acute intervention.ResultsClinicians recorded their suspicion in 11,919 (99%) of 12,044 patients enrolled in the parent study. Intra‐abdominal injuries undergoing acute intervention were diagnosed in 203 (2%) patients. Abdominal CT scans were obtained in the ED in 2,302 of the 2,667 (86%, 95% confidence interval [CI] = 85% to 88%) enrolled patients with clinician suspicion ≥1% and in 3,016 of the 9,252 (33%, 95% CI = 32% to 34%) patients with clinician suspicion  50% previamente a conocer la tomografía computarizada (TC) abdominal (si fue realizada). La LIA con necesidad de intervención urgente se definió como laparotomía terapéutica, embolización angiográfica, transfusión de sangre por hemorragia intrabdominal o administración de fluidos intravenosos durante 2 o más días en aquéllos con lesiones pancreáticas o gastrointestinales. Los pacientes se consideraron positivos para la sospecha clínica si la sospecha se documentó como ≥1%. La sospecha > 1% se comparó con la presencia de cualquier variable en la regla de predicción para la identificación de niños con LIA con necesidad de una intervención urgente.ResultadosLos clínicos documentaron su sospecha en 11.919 (99%) de los 12.044 pacientes incluidos en el estudio original. La LIA con necesidad de intervención urgente se diagnosticó en 203 (2%) pacientes. Las TC abdominales se obtuvieron en el SU en 2.302 de los 2.667 pacientes (86%, IC95% = 85% a 88%) incluidos con sospecha clínica ≥1%; y en 3.016 de los 9.252 pacientes (33%, IC95% = 32% a 34%) con sospecha clínica < 1%. La sensibilidad de la regla de predicción para LIA con necesidad de intervención aguda fue mayor que la sospecha clínica ≥1% (197 de 203, 97,0%, IC95% = 93,7% a 98,9%, frente a 168 de 203, 82,8%, IC95% = 76,9% a 87,7%, respectivamente; diferencia de 14,2%, IC95% = 8,6% a 20,0%). La especificidad de la regla de predicción, sin embargo, fue menor que la sospecha clínica (4,979 de los 11.716, 42,5%, IC95% = 41,6% a 43,4%, frente a 9,217 de los 11.716, 78,7%, IC95% = 77,9% a 79,4%, respectivamente; diferencia de –36,2%, IC95% = –37,3% a –35,0%). Treinta y cinco de los pacientes con sospecha clínica < 1% (0,4%, IC95% = 0,3% a 0,5%) tuvieron LIA con necesidad de intervención urgente.ConclusionesLa regla de predicción clínica derivada tuvo una sensibilidad mayor de forma significativa, pero menor especificidad que la sospecha clínica para la identificación de niños con necesidad de una intervención urgente. La mayor especificidad de la sospecha clínica, sin embargo, no se tradujo en la práctica clínica, ya que los clínicos obtuvieron más frecuentemente TC abdominales en los pacientes que consideraron de muy bajo riesgo. Si se validase, esta regla de predicción puede ayudar en la toma de decisiones clínicas sobre el uso de TC abdominal en los niños con traumatismo torácico cerrado.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113736/1/acem12739.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/113736/2/acem12739_am.pd

    NLOAD : an interactive, web-based modeling tool for nitrogen management in estuaries

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    Author Posting. © Ecological Society of America, 2007. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 17, Supple. (2007): S17–S30, doi:10.1890/05-1460.1.Eutrophication of estuaries is an increasing global concern that requires development of new tools to identify causes, quantify conditions, and propose management options that address this environmental problem. Since eutrophication is often associated with increased inputs of land-derived nitrogen to estuaries, we developed NLOAD, a user-friendly, web-based tool that brings together six different published models that predict nitrogen loading to estuaries and two models that estimate nitrogen concentrations in coastal waters. Here we describe each of the models, demonstrate how NLOAD is designed to function, and then use the models in NLOAD to predict nitrogen loads to Barnegat Bay, New Jersey (USA). The four models that we used to estimate nitrogen loads to Barnegat Bay, when adjusted, all had similar results that matched well with measured values and indicated that Barnegat Bay receives roughly 26 kg N·ha−1·yr−1. Atmospheric deposition was the dominant source of nitrogen to Barnegat Bay, followed by fertilizer nitrogen. Wastewater in Barnegat Bay is diverted to an offshore outfall and contributes no nitrogen to the system. The NLOAD tool has an additional feature that allows managers to assess the effectiveness of a variety of management options to reduce nitrogen loads. We demonstrate this feature of NLOAD through simulations in which fertilizer inputs to the Barnegat Bay watershed are reduced. Even modest cutbacks in the use of fertilizers on agricultural fields and lawns can be shown to reduce the amount of N entering Barnegat Bay.Support for the NLOAD tool came from the Cooperative Institute for Coastal and Estuarine Environmental Technologies (CICEET, CICEET-UNH grants #02-610 and #04-833). Additional funding was received from Environmental Defense

    Burden and Well-Being Among a Diverse Sample of Cancer, Congestive Heart Failure, and Chronic Obstructive Pulmonary Disease Caregivers

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    Three important causes of death in the U.S. (cancer, congestive heart failure [CHF], and chronic obstructive pulmonary disease [COPD]) are preceded by long periods of declining health; often, family members provide the majority of care for individuals who are living with serious illnesses and are at risk for impaired well-being

    Caregiver Experience During Advanced Chronic Illness and Last Year of Life

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    Caregivers of patients with serious illness endure significant burden, yet it is not clear at what stage of advanced illness patient and caregiver needs are greatest. This study compared prevalence and predictors of caregiver esteem and burden during two different stages of patients’ illnesses – advanced chronic illness and the last year of life

    A randomized, comparative pilot trial of family-based interpersonal psychotherapy for reducing psychosocial symptoms, disordered-eating, and excess weight gain in at-risk preadolescents with loss-of-control-eating: SHOMAKER et al.

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    Preadolescent loss-of-control-eating (LOC-eating) is a risk factor for excess weight gain and binge-eating-disorder. We evaluated feasibility and acceptability of a preventive family-based interpersonal psychotherapy (FB-IPT) program. FB-IPT was compared to family-based health education (FB-HE) to evaluate changes in children’s psychosocial functioning, LOC-eating, and body mass
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