17,673 research outputs found

    New approaches to the measurement of chlorophyll, related pigments and productivity in the sea

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    In the 1984 SBIR Call for Proposals, NASA solicited new methods to measure primary production and chlorophyll in the ocean. Biospherical Instruments Inc. responded to this call with a proposal first to study a variety of approaches to this problem. A second phase of research was then funded to pursue instrumentation to measure the sunlight stimulated naturally occurring fluorescence of chlorophyll in marine phytoplankton. The monitoring of global productivity, global fisheries resources, application of above surface-to-underwater optical communications systems, submarine detection applications, correlation, and calibration of remote sensing systems are but some of the reasons for developing inexpensive sensors to measure chlorophyll and productivity. Normally, productivity measurements are manpower and cost intensive and, with the exception of a very few expensive multiship research experiments, provide no contemporaneous data. We feel that the patented, simple sensors that we have designed will provide a cost effective method for large scale, synoptic, optical measurements in the ocean. This document is the final project report for a NASA sponsored SBIR Phase 2 effort to develop new methods for the measurements of primary production in the ocean. This project has been successfully completed, a U.S. patent was issued covering the methodology and sensors, and the first production run of instrumentation developed under this contract has sold out and been delivered

    Control system for hunger and its implications in animals and man

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    The synthesis of some acylglycines and related oxazolones

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    Sepsis caused by bloodstream infection in patients in the intensive care unit: the impact of inactive empiric antimicrobial therapy on outcome

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    Background: Sepsis is one of the leading causes of death in the UK. Aims: The aims of this study were to identify the rate of inactive antimicrobial therapy (AMT) in the ICU and whether inactive AMT had an effect on in hospital mortality, ICU mortality, 90-day mortality and length of hospital stay. Additionally, we wanted to identify risk factors for receiving inactive AMT. Methods: This was a retrospective observational study conducted at Glasgow Royal Infirmary ICU between January 2010 and December 2013, with 12,000 blood cultures taken over this time period, of which n=127 were deemed clinically significant. Multivariate logistic regression was used to identify risk factors independently associated with mortality. To identify risk factors for receiving inactive AMT a univariable and a subsequent multivariate analysis was constructed. Results: The rate of inactive AMT was 47% (n =60). Our multivariate analysis showed that receiving antibiotics within the first 24 hours of ICU admission led to a reduced mortality (RR 1.70; 95% CI 1.19-2.44.) Furthermore, it showed that severity of illness (as defined by SIRS criteria sepsis vs septic shock) increased mortality (OR 9.87; 95% CI 1.73-55.5). However, inactive AMT did not increase mortality (OR 1.07; 95% CI 0.47-2.41) or length of hospital stay (53.2 vs 69.1 days p=0.348.) We identified fungal bloodstream infection as a risk factor for receiving inactive AMT (OR 5.10;95% CI 1.29-20.14. Conclusion: Mortality from sepsis is influenced by multiple factors. We were unable to demonstrates that inactive AMT had an effect on mortality in sepsis

    Seasonal Dynamics of Fish Assemblages on Breakwaters and Natural Rocky Reefs in a Temperate Estuary: Consistent Assemblage Differences Driven by Sub-Adults

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    Development of infrastructure around cities is rapidly increasing the amount of artificial substrate (termed artificial reef, `AR?) in coastal marine habitats. However, effects of ARs on marine communities remain unknown, because it is unclear whether ARs can maintain similar communities to natural reefs. We investigated whether well-established (> 30 years old) breakwaters could consistently approximate fish assemblages on interspersed rocky reefs in a temperate estuary over 6 consecutive seasons using regular visual surveys between June 2009 (winter) and November 2010 (spring). We examined whether assemblage differences between reef types were driven by differences in juvenile recruitment, or were related to differences in older life-stages. Assemblages on both reef types were dominated by juveniles (61% of individuals) and sub-adults (34% of individuals). Seasonal fluctuations in assemblage parameters (species richness, diversity, sub-adult abundance) were similar between reef types, and levels of species diversity and assemblage composition were generally comparable. However, abundance and species richness were consistently higher (1.9-7.6 and 1.3-2.6 times, respectively) on breakwaters. These assemblage differences could not be explained by differences in juvenile recruitment, with seasonal patterns of recruitment and juvenile species found to be similar between reef types. In contrast, abundances of sub-adults were consistently higher (1.1-12 times) at breakwaters, and assemblage differences appeared to be driven by this life-stage. Our results indicate that breakwaters in temperate estuaries are capable of supporting abundant and diverse fish assemblages with similar recruitment process to natural reefs. However, breakwaters may not approximate all aspects of natural assemblage structure, with differences maintained by a single-life stage in some cases

    Synthesis of hetero-bifunctional, end-capped oligo-EDOT derivatives

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    Conjugated oligomers of 3,4-ethylenedioxythiophene (EDOT) are attractive materials for tissue engineering applications, and as model systems for studying the properties of the widely used polymer PEDOT. We report here the facile synthesis of a series of keto-acid end-capped oligo-EDOT derivatives (n = 2-7) through a combination of a glyoxylation end capping strategy and iterative direct arylation chain extension. Importantly, these structures not only represent the longest oligo-EDOTs reported, but are also bench stable in contrast to previous reports on such oligomers. The constructs reported here can undergo subsequent derivatization for integration into higher order architectures, such as those required for tissue engineering applications. The synthesis of hetero-bifunctional constructs, as well as those containing mixed monomer units is also reported, allowing further complexity to be installed in a controlled manner. Finally, we describe the optical and electrochemical properties of these oligomers and demonstrate the importance of the keto-acid in determining their characteristics

    Black hole boundaries

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    Classical black holes and event horizons are highly non-local objects, defined in relation to the causal past of future null infinity. Alternative, quasilocal characterizations of black holes are often used in mathematical, quantum, and numerical relativity. These include apparent, killing, trapping, isolated, dynamical, and slowly evolving horizons. All of these are closely associated with two-surfaces of zero outward null expansion. This paper reviews the traditional definition of black holes and provides an overview of some of the more recent work on alternative horizons.Comment: 27 pages, 8 figures, invited Einstein Centennial Review Article for CJP, final version to appear in journal - glossary of terms added, typos correcte

    Horizon energy and angular momentum from a Hamiltonian perspective

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    Classical black holes and event horizons are highly non-local objects, defined in terms of the causal past of future null infinity. Alternative, (quasi)local definitions are often used in mathematical, quantum, and numerical relativity. These include apparent, trapping, isolated, and dynamical horizons, all of which are closely associated to two-surfaces of zero outward null expansion. In this paper we show that three-surfaces which can be foliated with such two-surfaces are suitable boundaries in both a quasilocal action and a phase space formulation of general relativity. The resulting formalism provides expressions for the quasilocal energy and angular momentum associated with the horizon. The values of the energy and angular momentum are in agreement with those derived from the isolated and dynamical horizon frameworks.Comment: 39 pages, 3 figures, Final Version : content essentially unchanged but many small improvements made in response to referees, a few references adde
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