885 resultados para Potential of maximum entropy
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The potential of solid phase microextraction (SPME) in the analysis of explosives is demonstrated. A sensitive, rapid, solventless and inexpensive method for the analysis of explosives and explosive odors from solid and liquid samples has been optimized using SPME followed by HPLC and GC/ECD. SPME involves the extraction of the organic components in debris samples into sorbent-coated silica fibers, which can be transferred directly to the injector of a gas chromatograph. SPME/HPLC requires a special desorption apparatus to elute the extracted analyte onto the column at high pressure. Re suits for use of GC[ECD is presented and compared to the results gathered by using HPLC analysis. The relative effects of controllable variables including fiber chemistry, adsorption and desorption temperature, extraction time, and desorption time have been optimized for various high explosives.
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The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism's adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from previous compilations by other authors. Data were read from tables or digitized from graphs. Only measurements made on individuals of know size, or groups of individuals of similar and known size were included. We show that clearance and respiration rates have life-form-dependent allometries that have similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size within taxa is related to the inherent decrease in feeding efficiency of any particular feeding mode. The transitions between feeding mode and simultaneous transitions in clearance and respiration rates may then represent adaptations to the food environment and be the result of the optimization of tradeoffs that allow sufficient feeding and growth rates to balance mortality.
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Date of Acceptance: 21/09/2015 This study was funded by NHS Health Scotland. The opinions expressed in this paper as those of the authors alone and are not necessarily those of NHS Health Scotland. The funders had no role in the conduct of the research.
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Date of Acceptance: 21/09/2015 This study was funded by NHS Health Scotland. The opinions expressed in this paper as those of the authors alone and are not necessarily those of NHS Health Scotland. The funders had no role in the conduct of the research.
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Understanding past changes in sea surface temperatures (SSTs) is crucial; however, existing proxies for reconstructing past SSTs are hindered by unknown ancient seawater composition (foraminiferal Mg/Ca and d18O), or reflect subsurface temperatures (TEX86) or have a limited applicable temperature range (Uk'37). We examine clumped isotope (D47) thermometry to fossil coccolith-rich material as an SST proxy, as clumped isotopes are independent of original seawater composition and applicable to a wide temperature range and coccolithophores are widespread and dissolution resistant. The D47-derived temperatures from <63, <20, <10 and 2-5 µm size fractions of two equatorial Pacific late Miocene-early Pliocene sediment samples (c1; c2) range between ~18-29 {degree sign}C, with c1 temperatures consistently above c2. Removing the >63 µm fraction removes most non-mixed layer components; however, the D47-derived temperatures display an unexpected slight decreasing trend with decreasing size fraction. This unexpected trend could partly arise because larger coccoliths (5-12 µm) are removed during the size fraction separation process. The c1 and <63 µm c2 D47-derived temperatures are comparable to concurrent Uk'37 SSTs. The <20, <10 and 2-5 µm c2 D47-derived temperatures are consistently cooler than expected. The D47-Uk'37 temperature offset is probably caused by abiotic/diagenetic calcite present in the c2 2-5 µm fraction (~53% by area), which potentially precipitated at bottom water temperatures of ~6 {degree sign}C . Our results indicate that clumped isotopes on coccolith-rich sediment fractions have potential as an SST proxy, particularly in tropical regions, providing that careful investigation of the appropriate size fraction for the region and timescale is undertaken.
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Organic geochemical studies on samples from Holes 487, 488, and 490 in the southern Mexico Middle America Trench provided an opportunity to characterize the organic fraction of the sedimentary section in an active trench environment and to project the petroleum-producing potential of the extracted lipid fractions. The samples were geologically young and of shallow burial history. Samples from Hole 487, located on the oceanic plate, range in age from late Miocene to middlelate Pleistocene. Samples from Hole 488, representing undifferentiated Quaternary sediment, were collected on the landward side of the lower trench slope. Miocene(?) to Quaternary sediments from Hole 490 were obtained from the upper slope immediately seaward of the inferred location of the continental crust.
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Given the importance of gender in consumer research, one might expect feminist perspectives to be at the forefront of critical engagement with consumer behaviour theory. However, in recent years, feminist voices have been barely audible. This paper explores the value of, and insights offered by, feminist theories and feminist activism, and how feminist theory and practice has altered our understanding of gendered consumption. It then argues that postmodern and postfeminist perspectives have diluted feminism's transformative potential, leading to a critical impasse in marketing and consumer research. In conclusion, we suggest that feminist perspectives, notably materialist feminism, might open up fresh new possibilities for critique, and interesting and worthwhile areas for transformative research in consumer behaviour.
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The discovery of an ever-expanding plethora of coding and non-coding RNAs with nodal and causal roles in the regulation of lung physiology and disease is reinvigorating interest in the clinical utility of the oligonucleotide therapeutic class. This is strongly supported through recent advances in nucleic acids chemistry, synthetic oligonucleotide delivery and viral gene therapy that have succeeded in bringing to market at least three nucleic acid-based drugs. As a consequence, multiple new candidates such as RNA interference modulators, antisense, and splice switching compounds are now progressing through clinical evaluation. Here, manipulation of RNA for the treatment of lung disease is explored, with emphasis on robust pharmacological evidence aligned to the five pillars of drug development: exposure to the appropriate tissue, binding to the desired molecular target, evidence of the expected mode of action, activity in the relevant patient population and commercially viable value proposition.
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The Green Economy offers real possibilities for productive innovation, economic growth and employment creation in Spain. These three factors are critical to facilitate the necessary change in the productive model to overcome the crisis. However, the measures taken by the current Conservative government have moved in the opposite direction: significant cutting in incentives for renewable, increasing tax burden on renewable energy production to self-consumption and privatizing public spaces of social and environmental interest. This hinders the achievement of the environmental objectives of the Europe 2020 strategy. A strategy that is born already in itself highly limited, unambitious and subordinated to the interests of energy oligopolies and the imperatives of the Stability and Growth Pact (Maastricht) and the Austerity policies imposed from EU institutions to overcome the 2008 financial crisis. So the Ecological Transition goes further, claiming a substantially change in Economic Policy away form the increasing commodification proposed by the Green Economy. Despite these limitations, young and unemployed people have much to gain from a comprehensive development of environmental industries. Therefore, innovative-sustainable plans, investment and training in green sectors are necessary to make easier the transition from a services low-valued economy to an innovative and sustainable model to make our country an environmental reference in Europe.
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Boccardia proboscidea is a recently introduced polychaete in South Africa where it is a notorious pest of commercially reared abalone. Populations were originally restricted to abalone farms but a recent exodus into the wild at some localities has raised conservation concerns due to the species’ invasive status in other parts of the world. Here, we assessed the dispersal potential of B. proboscidea by using a population genetic and oceanographic modeling approach. Since the worm is in its incipient stages of a potential invasion, we used the closely related Polydora hoplura as a proxy due its similar reproductive strategy and its status as a pest of commercially reared oysters in the country. Populations of P. hoplura were sampled from seven different localities and a section of the mtDNA gene, Cyt b and the intron ATPSa was amplified. A high resolution model of the coastal waters around southern Africa was constructed using the Regional Ocean Modeling System. Larvae were represented by passive drifters that were deployed at specific points along the coast and dispersal was quantified after a 12-month integration period. Our results showed discordance between the genetic and modeling data. There was low genetic structure (Φ = 0.04 for both markers) and no geographic patterning of mtDNA and nDNA haplotypes. However, the dispersal model found limited connectivity around Cape Point—a major phylogeographic barrier on the southern African coast. This discordance was attributed to anthropogenic movement of larvae and adult worms due to vectors such as aquaculture and shipping. As such, we hypothesized that cryptic dispersal could be overestimating genetic connectivity. Though wild populations of B. proboscidea could become isolated due to the Cape Point barrier, anthropogenic movement may play the critical role in facilitating the dispersal and spread of this species on the southern African coast.
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Boccardia proboscidea is a recently introduced polychaete in South Africa where it is a notorious pest of commercially reared abalone. Populations were originally restricted to abalone farms but a recent exodus into the wild at some localities has raised conservation concerns due to the species’ invasive status in other parts of the world. Here, we assessed the dispersal potential of B. proboscidea by using a population genetic and oceanographic modeling approach. Since the worm is in its incipient stages of a potential invasion, we used the closely related Polydora hoplura as a proxy due its similar reproductive strategy and its status as a pest of commercially reared oysters in the country. Populations of P. hoplura were sampled from seven different localities and a section of the mtDNA gene, Cyt b and the intron ATPSa was amplified. A high resolution model of the coastal waters around southern Africa was constructed using the Regional Ocean Modeling System. Larvae were represented by passive drifters that were deployed at specific points along the coast and dispersal was quantified after a 12-month integration period. Our results showed discordance between the genetic and modeling data. There was low genetic structure (Φ = 0.04 for both markers) and no geographic patterning of mtDNA and nDNA haplotypes. However, the dispersal model found limited connectivity around Cape Point—a major phylogeographic barrier on the southern African coast. This discordance was attributed to anthropogenic movement of larvae and adult worms due to vectors such as aquaculture and shipping. As such, we hypothesized that cryptic dispersal could be overestimating genetic connectivity. Though wild populations of B. proboscidea could become isolated due to the Cape Point barrier, anthropogenic movement may play the critical role in facilitating the dispersal and spread of this species on the southern African coast.
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This article considers how the education systems of divided societies have been shaped in response to the experience of ethnic and religious conflict. The analysis identifies two competing priorities in such contexts – the development of social cohesion and the protection of cultural, ethnic and religious identities - and explores how these may be reconciled through a model of ‘shared education’. Drawing on research evidence and recent experience of shared education in relation to Northern Ireland, the Former Yugoslav Republic of Macedonia and Cyprus, we reflect on the advantages and challenges of this model in areas experiencing conflict and division.
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AIMS: Circulating Angiogenic Cells (CACs) promote revascularization of ischemic tissues although their underlying mechanism of action and the consequences of delivering varying numbers of these cells for therapy remain unknown. This study investigates molecular mechanisms underpinning CAC modulation of blood vessel formation.
METHODS & RESULTS: CACs at low (2x10(5)cells/ml) and mid (2x10(6)cells/ml) cellular densities significantly enhanced endothelial cell (EC) tube formation in vitro, while high density CACs (2x10(7)cells/ml) significantly inhibited this angiogenic process. In vivo, Matrigel-based angiogenesis assays confirmed mid-density CACs as pro-angiogenic and high density CACs as anti-angiogenic. Secretome characterization of CAC-EC conditioned media identified pentraxin 3 (PTX3) as only present in the high density CAC-EC co-culture. Recombinant PTX3 inhibited endothelial tube formation in vitro and in vivo Importantly, our data revealed that the anti-angiogenic effect observed in high density CAC-EC co-cultures was significantly abrogated when PTX3 bioactivity was blocked using neutralizing antibodies or PTX3 siRNA in endothelial cells. We show evidence for an endothelial source of PTX3, triggered by exposure to high density CACs. In addition, we confirmed that PTX3 inhibits FGF2-mediated angiogenesis, and that the PTX3 N-terminus, containing the FGF-binding site, is responsible for such anti-angiogenic effects.
CONCLUSIONS: Endothelium, when exposed to high density CACs, releases PTX3 which markedly impairs the vascular regenerative response in an autocrine manner. Therefore, CAC density and accompanying release of angiocrine PTX3 are critical considerations when using these cells as a cell therapy for ischemic disease.