265 research outputs found

    Grand canonical partition functions for multi level para Fermi systems of any order

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    A general formula for the grand canonical partition function for a para Fermi system of any order and of any number of levels is derived.Comment: 9 pages, latex, no figure

    Connectivity and Nitrate Uptake Potential of Intermittent Streams in the Northeast USA

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    Non-perennial streams dominate the extent of stream networks worldwide. Intermittent streams can provide ecosystem services to the entire network—including nitrate uptake to alleviate eutrophication of coastal waters—and are threatened by lack of legal protection. We examined 12 intermittent streams in the temperate, humid climate of the Northeast USA. Over 3 years of monitoring, continuous flow was observed a median of 277 d yr−1, with no-flow conditions from early summer into fall. Estimated median discharge was 2.9 L s−1 or 0.36mm d−1. All intermittent streams originated from source wetlands (median area: 0.27 ha) and the median length of the intermittent stream from the source wetland to the downstream perennial stream was 344m. Through regional geospatial analysis with high resolution orthophotography, we estimated that widely available, “high resolution” (1:24,000) hydrography databases (e.g., NHDPlus HR) only displayed 43% of the total number of intermittent streams. Whole-stream gross nitrate-N uptake rates were estimated at six intermittent streams during continuous flow conditions using pulse additions of nitrate and a conservative tracer. These rates displayed high temporal variability (range: no detect to over 6,000mg N m−1 d−1); hot moments were noted in nine of the 65 pulse additions. Whole-stream gross nitrate-N uptake rates were significantly inversely related to discharge, with no measurable rates above 7 L s−1. Temperature was significantly positively correlated with whole-stream gross nitrate-N uptake rates, with more hot moments in the spring. Microbial assays demonstrated that nitrate cycling in intermittent streams are consistent with results from low order, perennial forested streams and highlighted the importance of debris dams and pools—potential locations for transient storage. Our assessment suggests that intermittent streams in our region may annually contribute 24–47% of the flow to perennial streams and potentially remove 4.1 to 80.4 kg nitrate-N km−2 annually. If development in these areas continues, perennial streams are in danger of losing a portion of their headwaters and potential nitrate uptake areas may become nitrate sources to downstream areas. These results argue to manage fluvial systems with a holistic approach that couples intermittent and perennial components

    Evaluating the content validity of two versions of an instrument used in measuring pediatric pain knowledge and attitudes in the Ghanaian context

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    In this article, we compared the content validity of two instruments used in measuring pediatric pain knowledge and attitudes. This was considered necessary due to the universal differences in culture, semantics and healthcare resources in different parts of the globe. Thirteen (13) pediatric experts in Ghana assessed the content validity of two instruments: the 42-item Pediatric Nurses' Knowledge and Attitudes Survey Regarding Pain (PNKAS) and the 41-item Pediatric Healthcare Providers' Knowledge and Attitudes Survey Regarding Pain (PHPKASRP). The relevance and clarity of each item on these instruments were rated on a four-point likert scaled options from 1 (not relevant/ not clear) to 4 (very relevant/ very clear). The item-level content validity index (I-CVI) was calculated by dividing the number of experts who rated an item with 3 or 4 by the total number of experts. The average scale-level content validity index (S-CVI/Ave) was also estimated by summing up the I-CVIs of all items and dividing them by the total number of items. The I-CVIs on the PNKAS ranged from 0.62 to 1.00 for the relevance component and 0.69 to 1.00 for the clarity component. The I-CVIs on the PHPKASRP ranged from 0.62 to 1.00 for both the relevance and clarity components. The S-CVI/Ave were 0.87 and 0.89 for the relevance and clarity aspects on the PNKAS respectively. The S-CVI/Ave for the PHPKASRP instrument were 0.86 and 0.89 for the relevance and clarity aspects correspondingly. At the end of the validation process, 5 items were revised on both instruments whilst 37 and 36 items were maintained on the PNKAS and PHPKASRP instruments respectively. The PNKAS and PHPKASRP have an acceptable level of content validity in the Ghanaian context and recommended for educational and research purposes. Other forms of validity and reliability of these instruments should also be examined in future studies.</p

    Longer wings for faster springs – wing length relates tospring phenology in a long-distanc e migrant across its range

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    In migratory birds, morphological adaptations for efficient migratory flight often oppose morphological adaptations for efficient behavior during resident periods. This includes adaptations in wing shape for either flying long distances or foraging in the vegetation and in climate-driven variation of body size. In addition, the timing of migratory flights and particularly the timely arrival at local breeding sites is crucial because fitness prospects depend on site-specific phenology. Thus, adaptations for efficient long-distance flights might be also related to conditions at destination areas. For an obligatory long-distance migrant, the common nightingale, we verified that wing length as the aerodynamically important trait, but not structural body size increased from the western to the eastern parts of the species range. In contrast with expectation from aerodynamic theory, however, wing length did not increase with increasing migration distances. Instead, wing length was associated with the phenology at breeding destinations, namely the speed of local spring green-up. We argue that longer wings are beneficial for adjusting migration speed to local conditions for birds breeding in habitats with fast spring green-up and thus short optimal arrival periods. We suggest that the speed of spring green-up at breeding sites is a fundamental variable determining the timing of migration that fine tune phenotypes in migrants across their range

    Polynomial super-gl(n) algebras

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    We introduce a class of finite dimensional nonlinear superalgebras L=L0ˉ+L1ˉL = L_{\bar{0}} + L_{\bar{1}} providing gradings of L0ˉ=gl(n)sl(n)+gl(1)L_{\bar{0}} = gl(n) \simeq sl(n) + gl(1). Odd generators close by anticommutation on polynomials (of degree >1>1) in the gl(n)gl(n) generators. Specifically, we investigate `type I' super-gl(n)gl(n) algebras, having odd generators transforming in a single irreducible representation of gl(n)gl(n) together with its contragredient. Admissible structure constants are discussed in terms of available gl(n)gl(n) couplings, and various special cases and candidate superalgebras are identified and exemplified via concrete oscillator constructions. For the case of the nn-dimensional defining representation, with odd generators Qa,QˉbQ_{a}, \bar{Q}{}^{b}, and even generators Eab{E^{a}}_{b}, a,b=1,...,na,b = 1,...,n, a three parameter family of quadratic super-gl(n)gl(n) algebras (deformations of sl(n/1)sl(n/1)) is defined. In general, additional covariant Serre-type conditions are imposed, in order that the Jacobi identities be fulfilled. For these quadratic super-gl(n)gl(n) algebras, the construction of Kac modules, and conditions for atypicality, are briefly considered. Applications in quantum field theory, including Hamiltonian lattice QCD and space-time supersymmetry, are discussed.Comment: 31 pages, LaTeX, including minor corrections to equation (3) and reference [60

    Highly sensitive feature detection for high resolution LC/MS

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    <p>Abstract</p> <p>Background</p> <p>Liquid chromatography coupled to mass spectrometry (LC/MS) is an important analytical technology for e.g. metabolomics experiments. Determining the boundaries, centres and intensities of the two-dimensional signals in the LC/MS raw data is called feature detection. For the subsequent analysis of complex samples such as plant extracts, which may contain hundreds of compounds, corresponding to thousands of features – a reliable feature detection is mandatory.</p> <p>Results</p> <p>We developed a new feature detection algorithm <it>centWave </it>for high-resolution LC/MS data sets, which collects regions of interest (partial mass traces) in the raw-data, and applies continuous wavelet transformation and optionally Gauss-fitting in the chromatographic domain. We evaluated our feature detection algorithm on dilution series and mixtures of seed and leaf extracts, and estimated recall, precision and F-score of seed and leaf specific features in two experiments of different complexity.</p> <p>Conclusion</p> <p>The new feature detection algorithm meets the requirements of current metabolomics experiments. <it>centWave </it>can detect close-by and partially overlapping features and has the highest overall recall and precision values compared to the other algorithms, <it>matchedFilter </it>(the original algorithm of <it>XCMS</it>) and the centroidPicker from <it>MZmine</it>. The <it>centWave </it>algorithm was integrated into the Bioconductor R-package <it>XCMS </it>and is available from <url>http://www.bioconductor.org/</url></p

    PIP5KIβ Selectively Modulates Apical Endocytosis in Polarized Renal Epithelial Cells

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    Localized synthesis of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] at clathrin coated pits (CCPs) is crucial for the recruitment of adaptors and other components of the internalization machinery, as well as for regulating actin dynamics during endocytosis. PtdIns(4,5)P2 is synthesized from phosphatidylinositol 4-phosphate by any of three phosphatidylinositol 5-kinase type I (PIP5KI) isoforms (α, β or γ). PIP5KIβ localizes almost exclusively to the apical surface in polarized mouse cortical collecting duct cells, whereas the other isoforms have a less polarized membrane distribution. We therefore investigated the role of PIP5KI isoforms in endocytosis at the apical and basolateral domains. Endocytosis at the apical surface is known to occur more slowly than at the basolateral surface. Apical endocytosis was selectively stimulated by overexpression of PIP5KIβ whereas the other isoforms had no effect on either apical or basolateral internalization. We found no difference in the affinity for PtdIns(4,5)P2-containing liposomes of the PtdIns(4,5)P2 binding domains of epsin and Dab2, consistent with a generic effect of elevated PtdIns(4,5)P2 on apical endocytosis. Additionally, using apical total internal reflection fluorescence imaging and electron microscopy we found that cells overexpressing PIP5KIβ have fewer apical CCPs but more internalized coated structures than control cells, consistent with enhanced maturation of apical CCPs. Together, our results suggest that synthesis of PtdIns(4,5)P2 mediated by PIP5KIβ is rate limiting for apical but not basolateral endocytosis in polarized kidney cells. PtdIns(4,5)P2 may be required to overcome specific structural constraints that limit the efficiency of apical endocytosis. © 2013 Szalinski et al

    Designation processes and semantic substitutions used by european portuguese children in a vocabulary test

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    This research study focus on the designation processes and semantic substitutions of each word on the vocabulary sub-task from the language test for children – ABFW, standardized in Brazil and adapted to European Portuguese, as well as the comparison of the results obtained in the two countries, to analyze the relevance of their extensibility to the Portuguese population. Methods: The test was applied to 150 children from 5 to 6 years old, of typical development. The test consists of 9 conceptual categories. Each category consists of different words, which were always assessed in the same sequential order. Results: The sample of this study showed a lower performance only in clothes, places and food semantic categories. All the other categories have outperformed the standard. The categories of vocabulary with higher percentage in the right designation of the words were colors and shapes, animals and toys and music instruments. The categories with a higher percentage of substitution processes, from the reference results, were: food and locations. The most recurrent substitution processes were the co-hyponym, words that designate semantic attributes, valorization of the visual stimulus, hypernym and parasynonyms Conclusion: Given the homogeneity of the results of this study with the results obtained with other studies in Brazil, this test reveal potentiality as an instrument for vocabulary assessment in Portugal.Objetivo: Este estudo teve por objetivo a análise e quantificação dos processos de designação e substituição semântica apresentados na prova do vocabulário do Teste de Linguagem Infantil ABFW, padronizado no Brasil e adaptado para Português Europeu (PE), assim como a comparação dos resultados obtidos nos dois países, de forma a analisar a pertinência da sua extensibilidade à população portuguesa. Métodos: A prova foi aplicada a 150 crianças de 5 e 6 anos de idade, de desenvolvimento típico, na Região Norte de Portugal. A prova é constituída por nove categorias conceituais e cada categoria formada por diferentes vocábulos, que foram avaliados sempre pela mesma ordem sequencial. Resultados: A amostra mostrou desempenho inferior, em relação à norma, apenas nas categorias semânticas vestuário, locais e alimentos. Todas as outras categorias revelaram desempenho superior. As categorias do vocabulário que apresentaram maior percentagem de respostas corretas foram: animais, formas e cores e brinquedos e instrumentos musicais. As categorias que apresentaram percentagem superior de processos de substituição, em relação à norma, foram alimentos e locais. Os processos de substituição mais utilizados foram: substituição por co-hipônimo, vocábulos que designam atributos semânticos, valorização do estímulo visual, hiperônimos e parassinônimos. Conclusão: Dada a homogeneidade dos resultados deste estudo com os resultados obtidos em outros estudos no Brasil, esta prova revela potencialidades como instrumento de avaliação do vocabulário em Portugal.This work is funded by CIEd – Research Centre on Education, projects UID/CED/1661/2013 and UID/CED/1661/2016, Institute of Education, University of Minho, through national funds of FCT/MCTESPT.info:eu-repo/semantics/publishedVersio

    Changes in treatment and mortality of acute myocardial infarction in Estonian tertiary and secondary care hospitals in 2001 and 2007

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    <p>Abstract</p> <p>Background</p> <p>High quality care for acute myocardial infarction (AMI) improves patient outcomes. Still, AMI patients are treated in hospitals with unequal access to percutaneous coronary intervention. The study compares changes in treatment and 30-day and 3-year mortality of AMI patients hospitalized into tertiary and secondary care hospitals in Estonia in 2001 and 2007.</p> <p>Results</p> <p>Final analysis included 423 cases in 2001 (210 from tertiary and 213 from secondary care hospitals) and 687 cases in 2007 (327 from tertiary and 360 from secondary care hospitals). The study sample in 2007 was older and had twice more often diabetes mellitus. The patients in the tertiary care hospitals underwent reperfusion for ST-elevation myocardial infarction, cardiac catheterization and revascularisation up to twice as often in 2007 as in 2001. In the secondary care, patient transfer for further invasive treatment into tertiary care hospitals increased (<it>P </it>< 0.001). Prescription rates of evidence-based medications for in-hospital and for outpatient use were higher in 2007 in both types of hospitals. However, better treatment did not improve significantly the short- and long-term mortality within a hospital type in crude and baseline-adjusted analysis. Still, in 2007 a mortality gap between the two hospital types was observed (<it>P </it>< 0.010).</p> <p>Conclusions</p> <p>AMI treatment improved in both types of hospitals, while the improvement was more pronounced in tertiary care. Still, better treatment did not result in a significantly lower mortality. Higher age and cardiovascular risk are posing a challenge for AMI treatment.</p
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