1,014 research outputs found

    Temperature Variability in a Subtropical Estuary and Implications for Common Snook Centropomus undecimalis, a Cold-Sensitive Fish

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    Variability in winter water temperature was compared among three habitat types (estuary, river, canal) in a subtropical estuarine system to explore how it might affect site selection and survival of a cold-sensitive fish, Common Snook Centropomus undecimalis. The study was conducted during three winters (2008–2010); a rapid cooling event occurred during the first winter, mild temperatures the second, and an extreme cold event in the third (an 80-yr event). During the extreme cold event in January 2010, catastrophic fish mortality occurred throughout the region that resulted in the emergency closure of the Common Snook recreational fishery. Over the entire studied estuarine system, dead Common Snook were reported at 43 sites; 26 of the sites were large fish kills consisting of 100–2,000 individuals. The distribution of mortality sites was widespread, although most were located in the estuary proper (n = 39), with only several in rivers and canals (n = 4). Temperature loggers recorded similar water temperatures among habitat types (estuary, river, canal), except during short periods (~3 d; up to 2°C) after cold fronts; this indicates that fish have distinct time constraints if searching for warmer water sites. During the short periods after cold fronts, canal water temperatures were the warmest and most stable, whereas the river and estuary temperature rankings varied

    Feeding Habits of Common Snook, Centropomus undecimalis, in Charlotte Harbor, Florida

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    We examined the feeding habits, ontogenetic and seasonal diet variations, and predator size–prey size relationships of common snook, Centropomus undecimalis, in Charlotte Harbor, Florida, through stomach contents analysis. A total of 694 stomachs were extracted from common snook (300–882 mm standard length [SL]) during a 24-month period (March 2000–February 2002); 432 stomachs contained prey items. At least 37 prey taxa were identified, including 19 that had not been previously reported. Fishes made up 71% of the prey by number and 90% by weight. Three prey items made up almost 50% of the diet numerically—Lagodon rhomboides, Anchoa spp., and Farfantepenaeus duorarum. Seven species made up more than 60% of the diet by weight—L. rhomboides, Cynoscion nebulosus, Mugil gyrans, Bairdiella chrysoura, Synodus foetens, Orthopristis chrysoptera, and Mugil cephalus. An ontogenetic shift in prey preference was identified in adult common snook at around 550 mm SL. Smaller individuals (300–549 mm SL) ate more F. duorarum, palaemonid shrimp, cyprinodontids, and Eucinostomus spp. than did larger individuals (550–882 mm SL), which ate more S. foetens, ariids, and sciaenids. Significant, positive relationships between predator size and prey size were observed between common snook and L. rhomboides, O. chrysoptera, portunid crabs, and all fish prey combined. Prey size selection contributed to some seasonal differences in their diet. For example, in winter when L. rhomboides are abundant in the estuary and small in size (mean = 23 mm SL), common snook ate few individuals, but they consumed many during summer when larger L. rhomboides (mean = 51 mm SL) were available. In summary, common snook are opportunistic predators that feed on a wide variety of prey and exploit specific-sized prey that are abundant in their environment

    Long-term site fidelity of endangered smalltooth sawfish (Pristis pectinata) from different mothers

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    Understanding how endangered species use nursery habitats is vital for recovery planning. Research on the smalltooth sawfish (Pristis pectinata) has shown that areas of estuarine nurseries, called hotspots, are used consistently. The objectives of our study were 1) to determine whether 10 young-of-the-year smalltooth sawfish in an artificial, non-main-stem portion (i.e., a seawall canal system) of a hotspot were descended from one or different mothers and 2) to document long-term habitat use by these individuals. At least 4 mothers contributed to the group, which comprised siblings, half-siblings, and unrelated individuals. Young sawfish exhibited site fidelity to their capture location, spending 61% of their time there. Continuous residency lasted as long as 86 days, but these fish made small-scale diel

    Synthesis of 3-D coronal-solar wind energetic particle acceleration modules

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    1. Introduction Acute space radiation hazards pose one of the most serious risks to future human and robotic exploration. Large solar energetic particle (SEP) events are dangerous to astronauts and equipment. The ability to predict when and where large SEPs will occur is necessary in order to mitigate their hazards. The Coronal-Solar Wind Energetic Particle Acceleration (C-SWEPA) modeling effort in the NASA/NSF Space Weather Modeling Collaborative [Schunk, 2014] combines two successful Living With a Star (LWS) (http://lws. gsfc.nasa.gov/) strategic capabilities: the Earth-Moon-Mars Radiation Environment Modules (EMMREM) [Schwadron et al., 2010] that describe energetic particles and their effects, with the Next Generation Model for the Corona and Solar Wind developed by the Predictive Science, Inc. (PSI) group. The goal of the C-SWEPA effort is to develop a coupled model that describes the conditions of the corona, solar wind, coronal mass ejections (CMEs) and associated shocks, particle acceleration, and propagation via physics-based modules. Assessing the threat of SEPs is a difficult problem. The largest SEPs typically arise in conjunction with X class flares and very fast (\u3e1000 km/s) CMEs. These events are usually associated with complex sunspot groups (also known as active regions) that harbor strong, stressed magnetic fields. Highly energetic protons generated in these events travel near the speed of light and can arrive at Earth minutes after the eruptive event. The generation of these particles is, in turn, believed to be primarily associated with the shock wave formed very low in the corona by the passage of the CME (injection of particles from the flare site may also play a role). Whether these particles actually reach Earth (or any other point) depends on their transport in the interplanetary magnetic field and their magnetic connection to the shock

    Enacting Hope through Narratives of Indigenous Language and Culture Reclamation

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    In globalizing landscapes, Indigenous ways of knowing and being persist in their connectedness to specific geographies, even as they are transformed by migrations, both forced and voluntary, and dynamic exchanges. This paper presents narratives of Indigenous and ally scholars which explore what it means to enact language and culture reclamation from a place of hope—by Indigenous peoples, for Indigenous communities—and in connection with distinct historical, political, and geographic sites. By naming the identities the authors represent—Chickasaw, Nez Perce, Eastern Shoshone/Northern Arapaho, Hopi, San Carlos Apache and Euro-American—we use a framework of hope to counter damaging assumptions of homogeneity of Indigenous communities while also searching for common themes to advance an agenda of decolonization across positionalities. Understanding that Indigenous sovereignties are built on “contingency with the beliefs, and understandings of the past” (Grande 250), we interrupt settler-colonial narratives which portray Indigenous languages and cultures as deficient and vanishing. Further, through narratives, we explore how disciplines such as linguistics, anthropology, education, and cultural studies can be interwoven to highlight experiences of identity reconciliation, spirituality through language revitalization, and storytelling as narrative reclamation. A critical culturally sustaining/revitalizing pedagogy unifies the narratives and provides a framework for attending to “asymmetrical power relations and legacies of colonization” (McCarty and Lee 8). In this way, Indigenous narratives of persistence and optimism find relevance in the global and local here and now while emphasizing the relevancy of hope as a rooted practice of relationality in Indigenous language and cultural education. Sharing narratives of hope acknowledges the experience of colonization, while privileging the hope in Indigenous knowledge as a return to the community and generator of new narratives.Ye

    Pulmonary vascular mechanical consequences of ischemic heart failure and implications for right ventricular function

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    Left heart failure (LHF) is the most common cause of pulmonary hypertension, which confers an increase in morbidity and mortality in this context. Pulmonary vascular resistance has prognostic value in LHF, but otherwise the mechanical consequences of LHF for the pulmonary vasculature and right ventricle (RV) remain unknown. We sought to investigate mechanical mechanisms of pulmonary vascular and RV dysfunction in a rodent model of LHF to address the knowledge gaps in understanding disease pathophysiology. LHF was created using a left anterior descending artery ligation to cause myocardial infarction (MI) in mice. Sham animals underwent thoracotomy alone. Echocardiography demonstrated increased left ventricle (LV) volumes and decreased ejection fraction at 4 wk post-MI that did not normalize by 12 wk post-MI. Elevation of LV diastolic pressure and RV systolic pressure at 12 wk post-MI demonstrated pulmonary hypertension (PH) due to LHF. There was increased pulmonary arterial elastance and pulmonary vascular resistance associated with perivascular fibrosis without other remodeling. There was also RV contractile dysfunction with a 35% decrease in RV end-systolic elastance and 66% decrease in ventricular-vascular coupling. In this model of PH due to LHF with reduced ejection fraction, pulmonary fibrosis contributes to increased RV afterload, and loss of RV contractility contributes to RV dysfunction. These are key pathologic features of human PH secondary to LHF. In the future, novel therapeutic strategies aimed at preventing pulmonary vascular mechanical changes and RV dysfunction in the context of LHF can be tested using this model

    Higher-order photon correlations in pulsed photonic crystal nanolasers

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    We report on the higher-order photon correlations of a high-β\beta nanolaser under pulsed excitation at room temperature. Using a multiplexed four-element superconducting single photon detector we measured g(n)(0)^{(n)}(\vec{0}) with nn=2,3,4. All orders of correlation display partially chaotic statistics, even at four times the threshold excitation power. We show that this departure from coherence and Poisson statistics is due to the quantum fluctuations associated with the small number of dipoles and photons involved in the lasing process

    Feasibility Study to Assess Canagliflozin Distribution and Sodium-Glucose Co-Transporter 2 Occupancy Using [18F]Canagliflozin in Patients with Type 2 Diabetes

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    Sodium-glucose co-transporter 2 (SGLT2) inhibitors, including canagliflozin, reduce the risk of cardiovascular and kidney outcomes in patients with and without type 2 diabetes, albeit with a large inter-individual variation. The underlying mechanisms for this variation in response might be attributed to differences in SGLT2 occupancy, resulting from individual variation in plasma and tissue drug exposure and receptor availability. We performed a feasibility study for the use of [ 18 F]Canagliflozin positron emission tomography (PET) imaging to determine the association between clinical canagliflozin doses and SGLT2 occupancy in patients with type 2 diabetes. We obtained two 90-min dynamic PET scans with diagnostic intravenous [ 18 F]Canagliflozin administration and a full kinetic analysis in seven patients with type 2 diabetes. Patients received 50, 100 or 300mg oral canagliflozin (n=2:4:1) 2.5 hours before the second scan. Canagliflozin pharmacokinetics and urinary glucose excretion were measured. The apparent SGLT2 occupancy was derived from the difference between the apparent volume of distribution of [ 18 F]Canagliflozin in the baseline and post-drug PET scans. Individual canagliflozin area under the curve from oral dosing until 24-hours (AUC P0-24h ) varied largely (range 1715-25747 μg/L*h, mean 10580 μg/L*h) and increased dose dependently with mean values of 4543, 6525 and 20012 μg/L*h for 50, 100 and 300mg respectively (P=0.046). SGLT2 occupancy ranged between 65 and 87%, but did not correlate with canagliflozin dose, plasma exposure or urinary glucose excretion. We report the feasibility of [ 18 F]Canagliflozin PET imaging to determine canagliflozin kidney disposition and SGLT2 occupancy. This suggests the potential of [ 18 F]Canagliflozin as a tool to visualize and quantify clinically SGLT2 tissue binding. </p

    London and beyond: essays in honour of Derek Keene

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    This volume contains selected papers from a major conference held in October 2008 to celebrate the 20th anniversary of the setting up of the Centre for Metropolitan History at the IHR, and the contribution of Professor Derek Keene to the Centre, the IHR and the wider world of scholarship. 'One of the pioneer volumes in the handsomely produced new Institute of Historical Research Conference series, this book serves as a fitting tribute to one of the most influential urban historians of our time.' - Ian Archer, Urban History, May 2013
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