40 research outputs found

    Galactic Point Sources of TeV Antineutrinos

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    High energy cosmic ray experiments have identified an excess from the region of the Galactic Plane in a limited energy range around 101810^{18} eV (EeV). This is very suggestive of neutrons as candidate primaries, because the directional signal requires relatively-stable neutral primaries, and time-dilated neutrons can reach Earth from typical Galactic distances when the neutron energy exceeds an EeV. We here point out that if the Galactic messengers are neutrons, then those with energies below an EeV will decay in flight, providing a flux of cosmic antineutrinos above a TeV which is {\it observable} at a kilometer-scale neutrino observatory. The expected event rate per year above 1 TeV in a detector such as IceCube, for example, is 20 antineutrino showers (all flavors) and a 1∘1^\circ directional signal of 4 νˉμ\bar \nu_\mu events. A measurement of this flux can serve to identify the first extraterrestrial point source of TeV antineutrinos.Comment: matches published versio

    Lessons from bright-spots for advancing knowledge exchange at the interface of marine science and policy

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    Evidence-informed decision-making is in increasing demand given growing pressures on marine environments. A way to facilitate this is by knowledge exchange among marine scientists and decision-makers. While many barriers are reported in the literature, there are also examples whereby research has successfully informed marine decision-making (i.e., 'bright-spots'). Here, we identify and analyze 25 bright-spots from a wide range of marine fields, contexts, and locations to provide insights into how to improve knowledge exchange at the interface of marine science and policy. Through qualitative surveys we investigate what initiated the bright-spots, their goals, and approaches to knowledge exchange. We also seek to identify what outcomes/impacts have been achieved, the enablers of success, and what lessons can be learnt to guide future knowledge exchange efforts. Results show that a diversity of approaches were used for knowledge exchange, from consultative engagement to genuine knowledge co-production. We show that diverse successes at the interface of marine science and policy are achievable and include impacts on policy, people, and governance. Such successes were enabled by factors related to the actors, processes, support, context, and timing. For example, the importance of involving diverse actors and managing positive relationships is a key lesson for success. However, enabling routine success will require: 1) transforming the ways in which we train scientists to include a greater focus on interpersonal skills, 2) institutionalizing and supporting knowledge exchange activities in organizational agendas, 3) conceptualizing and implementing broader research impact metrics, and 4) transforming funding mechanisms to focus on need-based interventions, impact planning, and an acknowledgement of the required time and effort that underpin knowledge exchange activities

    Red cell transfusions in neonatal care

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    Inter-NICU variation in rates and management of thrombocytopenia among very low birth-weight infants

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    OBJECTIVES: To investigate variation among neonatal intensive care units (NICUs) in prevalence and management of thrombocytopenia in infants and(SNAP). Platelet counts in the first 12 hours after birth and on day 3 of life were abstracted from the infants\u27 medical records. Thrombocytopenia was determined from the lowest platelet count in each of these time periods. RESULTS: There was variability in rates of thrombocytopenia among NICUs, even after controlling for risk factors (e.g., SNAP, small for gestational (SGA) age and maternal hypertension). One site had a high prevalence of thrombocytopenia, but the lowest percentage of infants with thrombocytopenia who received platelet transfusions. After controlling for SNAP, GA, SGA, Apgar score and incidence of thrombocytopenia, the odds of receiving platelets at this site, relative to the site with the highest transfusion rate, was 0.10 (95% CI 0.02 to 0.43). CONCLUSIONS: This multicenter study finds a 10-fold variation among NICU in the administration of platelets to their thrombocytopenic infants that cannot be explained by presence of thrombocytopenia or illness severity

    Variations in blood transfusions among newborn intensive care units. SNAP II Study Group

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    OBJECTIVES: Very low birth weight (\u3c 1500 g) infants frequently require packed red blood cell transfusions, and transfusion rates vary among neonatal intensive care units (NICUs). We analyzed transfusions and compared outcomes among NICUs. STUDY DESIGN: In a 6-site prospective study, we abstracted all newborns weighing \u3c 1500 g (total = 825) born between October 1994 and September 1995. Transfusion frequency and volume and phlebotomy number were analyzed by site and adjusted for birth weight and illness severity. We compared rates of intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, growth, and length of stay between the high and low transfuser NICUs. RESULTS: Sites differed significantly in mean birth weight, illness severity, number of transfusions, pretransfusion hematocrit, blood draws, and donor number. Multivariate adjustment for these risks showed that the highest transfusing NICU transfused an additional 24 cc/kg per baby during the first 14 days and 47 cc/kg per baby after 15 days, relative to the lowest transfusing NICU. The presence of arterial catheters increased the frequency of blood transfusions. The rates of intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia were not higher in the 2 lowest transfusing NICUs, nor were there differences in 28-day weight gain or length of stay. CONCLUSIONS: Major differences in transfusion practices for very low birth weight infants exist among NICUs. Because clinical outcomes were no different in lower transfuser NICUs, it is likely that transfusion and phlebotomy guidelines could result in fewer transfusions, fewer complications, and reduced cost

    Heritability of apnea of prematurity: a retrospective twin study

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    BACKGROUND: Apnea of prematurity (AOP) is a disturbance in respiratory rhythm defined by idiopathic pauses in breathing that reduce blood oxygen levels and/or heart rate. It is a major clinical problem among preterm infants. OBJECTIVES: The primary goal of this study was to estimate the genetic susceptibility to AOP in a cohort of preterm twins. A secondary aim was to identify risk factors associated with AOP in this cohort. METHODS: A single-center, retrospective study (2000-2008) was performed by using data from 317 premature twin pairs (weeks\u27 gestational age). Heritability estimates were determined by comparing intrapair AOP concordance between 56 monozygotic and 161 dizygotic twin pairs by using structural equation modeling. Risk factors of AOP among a cohort of 543 premature twins were assessed by using mixed-effects logistic regression. RESULTS: The heritability of AOP was 87% (95% confidence interval [CI]: 0.64-0.97) among same-gender twins. A gender-dependent model revealed that genetic factors accounted for 99% of the variance in male twins (95% CI: 0.89-1.00) and 78% of the variance in female twins (95% CI: 0.49-0.94). Significant risk factors for AOP were low gestational age (P CONCLUSIONS: These findings suggest that AOP has an important genetic basis underlying this developmental-related disorder of respiratory control. Future genomic studies may provide information on pathophysiological mechanisms that underlie AOP

    The platelet hyporeactivity of extremely low birth weight neonates is age-dependent

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    INTRODUCTION: We have previously demonstrated that, as compared to adults, the platelets of extremely low birth weight (ELBW) neonates are markedly hyporeactive on day 0-1 of life. The purpose of this study was to examine the age dependency of this hyporeactivity. MATERIALS AND METHODS: On days 0-1, 3-4, and 10-14, peripheral blood was collected from 14 stable ELBW neonates and compared to peripheral blood from normal adults run in parallel. Whole blood flow cytometry was used to examine the activation-dependent increase in platelet surface P-selectin (reflecting degranulation) and platelet surface binding of factor V/Va (reflecting platelet surface procoagulant activity) and decrease in platelet surface glycoprotein (GP) Ib (the von Willebrand factor receptor). RESULTS: In the physiologic milieu of whole blood, ELBW neonatal platelets on days 0-1 and 3-4 were markedly less reactive than adult platelets. However, by day 10-14, the platelet function of ELBW neonates improved significantly, although not completely to adult levels. CONCLUSIONS: The age-dependent platelet hyporeactivity of ELBW neonates demonstrated in this study may be a contributing factor to the similar age-dependent propensity of ELBW neonates to intraventricular hemorrhage

    Variation among neonatal intensive care units in narcotic administration

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    OBJECTIVES: To compare rates of narcotic administration for medically treated neonates in different neonatal intensive care units (NICUs) and to compare treated and untreated neonates to assess whether narcotics provided advantages or disadvantages for short-term outcomes, such as cardiovascular stability (ie, blood pressure and heart rate), hyperbilirubinemia, duration of respiratory support, growth, and the incidence of intraventricular hemorrhage. STUDY DESIGN: The medical charts of neonates weighing less than 1500 g, admitted to 6 NICUs (A-F), were abstracted. Neonates who had a chest tube or who had undergone surgery were excluded from the study, leaving the records of 1171 neonates. We modeled outcomes by linear or logistic regression, controlling for birth weight ( or =20) using the Score for Neonatal Acute Physiology (SNAP), and adjusted for NICU. RESULTS: Narcotic use varied by birth weight (g, 21%; 750-999 g, 13%; and 1000-1499 g, 8%), illness severity (low, 9%; medium, 19%; and high, 37%), day (1, 11%; 3, 6%; and 14, 2%), and NICU. We restricted analyses to the 1018 neonates who received mechanical ventilation on day 1. Logistic regression, adjusting for birth weight and SNAP, confirmed a 28.6-fold variation in narcotic administration (odds ratios, 4.1-28.6 vs NICU A). Several short-term outcomes also were associated with narcotic use, including more than 33 g of fluid retention on day 3 and a higher direct bilirubin level (6.8 micromol/L higher [0.4 mg/dL higher], P = .03). There were no differences in weight gain at 14 and 28 days or mechanical ventilatory support on days 14 and 28. Narcotic use was not associated with differences in worst blood pressure or heart rate or with increased length of hospital stay. CONCLUSIONS: Our study found a 28.6-fold variation among NICUs in narcotic administration in very low-birth-weight neonates. We were unable to detect any major advantages or disadvantages of narcotic use. We did not assess iatrogenic abstinence syndrome or long-term outcomes. These results indicate the need for randomized trials to rationalize these widely differing practices
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