984 research outputs found

    On the Origin of the -4.4 eV Band in CdTe(100)"

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    We calculate the bulk- (infinite system), (100)-bulk-projected- and (100)-Surface-projected Green's functions using the Surface Green's Function Matching method (SGFM) and an empirical tight-binding hamiltonian with tight-binding parameters (TBP) that describe well the bulk band structure of CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the top of the valence band at Γ\Gamma according to the results of Niles and H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by Angle-resolved photoelectron spectroscopy (ARPES). We give the first theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9

    Redescription of Nothobrya schubarti Arlé, 1961 (Collembola, Entomobryomorpha)

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    Three paratypes of Nothobrya schubarti Arl , 1961 were examined in connection with a forthcoming description of a new genus of Entomobryidae. Some of the features observed by Arl in 1961, appeared similar to those of the new genus. These included: small size, color, the presence of PAO, a falciform mucro, the trochanteral organ and the body setae. Observation of a specimen with SEM allowed us to see the PAO and the other characteristics described by Arl in more detail, but other features not described by him were seen which indicate that the genus belongs in subfamily Orchesellinae

    Decomposition of the Mean Squared Error and NSE Performance Criteria: Implications for Improving Hydrological Modelling

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    The mean squared error (MSE) and the related normalization, the Nash-Sutcliffe efficiency (NSE), are the two criteria most widely used for calibration and evaluation of hydrological models with observed data. Here, we present a diagnostically interesting decomposition of NSE (and hence MSE), which facilitates analysis of the relative importance of its different components in the context of hydrological modelling, and show how model calibration problems can arise due to interactions among these components. The analysis is illustrated by calibrating a simple conceptual precipitation-runoff model to daily data for a number of Austrian basins having a broad range of hydro-meteorological characteristics. Evaluation of the results clearly demonstrates the problems that can be associated with any calibration based on the NSE (or MSE) criterion. While we propose and test an alternative criterion that can help to reduce model calibration problems, the primary purpose of this study is not to present an improved measure of model performance. Instead, we seek to show that there are systematic problems inherent with any optimization based on formulations related to the MSE. The analysis and results have implications to the manner in which we calibrate and evaluate environmental models; we discuss these and suggest possible ways forward that may move us towards an improved and diagnostically meaningful approach to model performance evaluation and identification

    A new genus and species of Entomobryidae (Collembola, Entomobryomorpha) from the Iberian peninsula

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    A new genus and species, Hispanobrya barrancoi Jordana and Baquero, gen. n., sp. n. is described. It was found in the Gador Mountain range (Almer a, Spain). This genus is similar to Capbrya Barra, 1999, from South Africa. The distinguishing characteristics of the new genus are the presence of a post-antennal organ (PAO), no clear tenent hair, a characteristic unguis, the presence of a reduced trochanteral organ, and flattened body setae. The distribution of the bothriotricha is similar to that of the genus Capbrya

    Multi-purpose ocean energy platforms for offshore aquaculture farms

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    The Blue Growth strategy was laid out by the European Union (EU) in 2012 [1], with a view to realize sustainable development of the blue economy - based on the oceans, seas and coasts. Along the lines of the Blue Growth strategy, the present work investigates the performance of a multi-purpose platform (MPP) for use in an offshore aquaculture farm. The elements of offshore wind and fish feed storage are integrated in the same platform to support the energy demands of closely co-located aquaculture farms, at a location off the Scottish coast, with a water depth of 81 m. The work presented herein is part of the UK-China Investigation of the novel challenges of an integrated offshore multi-purpose platform (INNOMPP) project [2] (EPSRC Grant no. EP/R007497/1)

    Comparative distribution of human and avian type sialic acid influenza receptors in the pig

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    <p>Abstract</p> <p>Background</p> <p>A major determinant of influenza infection is the presence of virus receptors on susceptible host cells to which the viral haemagglutinin is able to bind. Avian viruses preferentially bind to sialic acid α2,3-galactose (SAα2,3-Gal) linked receptors, whereas human strains bind to sialic acid α2,6-galactose (SAα2,6-Gal) linked receptors. To date, there has been no detailed account published on the distribution of SA receptors in the pig, a model host that is susceptible to avian and human influenza subtypes, thus with potential for virus reassortment. We examined the relative expression and spatial distribution of SAα2,3-GalG(1-3)GalNAc and SAα2,6-Gal receptors in the major organs from normal post-weaned pigs by binding with lectins <it>Maackia amurensis agglutinins </it>(MAA II) and <it>Sambucus nigra agglutinin </it>(SNA) respectively.</p> <p>Results</p> <p>Both SAα2,3-Gal and SAα2,6-Gal receptors were extensively detected in the major porcine organs examined (trachea, lung, liver, kidney, spleen, heart, skeletal muscle, cerebrum, small intestine and colon). Furthermore, distribution of both SA receptors in the pig respiratory tract closely resembled the published data of the human tract. Similar expression patterns of SA receptors between pig and human in other major organs were found, with exception of the intestinal tract. Unlike the limited reports on the scarcity of influenza receptors in human intestines, we found increasing presence of SAα2,3-Gal and SAα2,6-Gal receptors from duodenum to colon in the pig.</p> <p>Conclusions</p> <p>The extensive presence of SAα2,3-Gal and SAα2,6-Gal receptors in the major organs examined suggests that each major organ may be permissive to influenza virus entry or infection. The high similarity of SA expression patterns between pig and human, in particular in the respiratory tract, suggests that pigs are not more likely to be potential hosts for virus reassortment than humans. Our finding of relative abundance of SA receptors in the pig intestines highlights a need for clarification on the presence of SA receptors in the human intestinal tract.</p

    Making Operation-based CRDTs Operation-based

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    Conflict-free Replicated Datatypes can simplify the design of predictable eventual consistency. They can be classified into state-based or operation-based. Operation-based approaches have the potential for allowing compact designs in both the sent message and the object state size, but cur- rent approaches are still far from this objective. Here we explore the design space for operation-based solutions, and we leverage the interaction with the middleware by offering a technique that delivers very compact solutions, while only broadcasting operation names and arguments.(undefined)(undefined

    Psychometric properties and validation of the Spanish versions of the overall anxiety and depression severity and impairment scales

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    Background Anxiety and depressive disorders are the most frequent disorders for which patients seek care in public health settings in Spain. This study aimed at validating the Overall Anxiety Severity and Impairment Scale (OASIS) and the Overall Depression Severity and Impairment Scale (ODSIS), which are brief screening scales for anxiety and depression consisting of only five items each. Methods The study was conducted in a Spanish clinical sample receiving outpatient mental health treatment (N = 339). A subsample of participants (n = 219) was assessed before and after receiving a course of cognitive-behavioral treatment. Results The results revealed excellent internal consistency estimates (Cronbach's alpha for the OASIS and the ODSIS was 0.87 and 0.94, respectively), along with promising convergent and discriminant validity and test-criterion relationships (i.e., moderate correlation with other measures of depression and anxiety, as well as with neuroticism, quality of life, adjustment, and negative affect). A one-dimensional structure was obtained for the OASIS and the ODSIS. The ROC analyses indicated an area under the curve of 0.83 for the OASIS and the ODSIS when predicting moderate-to-severe anxiety and depression, respectively. Good sensitivity to therapeutic change was also evidence and the analysis of the sensitivity as a function of 1-specificity area suggested a cutoff value of 10 for both scales. Limitations Inter-rater reliability of diagnoses with the ADIS-IV interview could not be investigated and the results obtained may not be generalizable to other samples and health settings. Conclusions The availability of these two short and psychometrically sound measures should make screening of anxiety and depressive symptoms in routine care more feasible

    Trait evolution, resource specialization and vulnerability to plant extinctions among Antillean hummingbirds

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    Species traits are thought to predict feeding specialization and the vulnerability of a species to extinctions of interaction partners, but the context in which a species evolved and currently inhabits may also matter. Notably, the predictive power of traits may require that traits evolved to fit interaction partners. Furthermore, local abiotic and biotic conditions may be important. On islands, for instance, specialized and vulnerable species are predicted to be found mainly in mountains, whereas species in lowlands should be generalized and less vulnerable. We evaluated these predictions for hummingbirds and their nectar-food plants on Antillean islands. Our results suggest that the rates of hummingbird trait divergence were higher among ancestral mainland forms before the colonization of the Antilles. In correspondence with the limited trait evolution that occurred within the Antilles, local abiotic and biotic conditions—not species traits—correlate with hummingbird resource specialization and the vulnerability of hummingbirds to extinctions of their floral resources. Specifically, hummingbirds were more specialized and vulnerable in conditions with high topographical complexity, high rainfall, low temperatures and high floral resource richness, which characterize the Antillean Mountains. These findings show that resource specialization and species vulnerability to extinctions of interaction partners are highly context-dependent.B.D., J.D.K., A.C.B., A.M.M.G. and C.R. thank the Danish National Research Foundation for its support of the Center for Macroecology, Evolution and Climate (grant no. DNRF96). P.K.M. thanks the São Paulo Research Foundation (FAPESP) for the postdoctoral grant (grant no. 2015/21457-4). B.I.S. was supported by the Natural Environment Research Council as part of the Cambridge Earth System Science NERC DTP (NE/L002507/1)

    18S rRNA is a reliable normalisation gene for real time PCR based on influenza virus infected cells

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    Background: One requisite of quantitative reverse transcription PCR (qRT-PCR) is to normalise the data with an internal reference gene that is invariant regardless of treatment, such as virus infection. Several studies have found variability in the expression of commonly used housekeeping genes, such as beta-actin (ACTB) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), under different experimental settings. However, ACTB and GAPDH remain widely used in the studies of host gene response to virus infections, including influenza viruses. To date no detailed study has been described that compares the suitability of commonly used housekeeping genes in influenza virus infections. The present study evaluated several commonly used housekeeping genes [ACTB, GAPDH, 18S ribosomal RNA (18S rRNA), ATP synthase, H+ transporting, mitochondrial F1 complex, beta polypeptide (ATP5B) and ATP synthase, H+ transporting, mitochondrial Fo complex, subunit C1 (subunit 9) (ATP5G1)] to identify the most stably expressed gene in human, pig, chicken and duck cells infected with a range of influenza A virus subtypes. Results: The relative expression stability of commonly used housekeeping genes were determined in primary human bronchial epithelial cells (HBECs), pig tracheal epithelial cells (PTECs), and chicken and duck primary lung-derived cells infected with five influenza A virus subtypes. Analysis of qRT-PCR data from virus and mock infected cells using NormFinder and BestKeeper software programmes found that 18S rRNA was the most stable gene in HBECs, PTECs and avian lung cells. Conclusions: Based on the presented data from cell culture models (HBECs, PTECs, chicken and duck lung cells) infected with a range of influenza viruses, we found that 18S rRNA is the most stable reference gene for normalising qRT-PCR data. Expression levels of the other housekeeping genes evaluated in this study (including ACTB and GPADH) were highly affected by influenza virus infection and hence are not reliable as reference genes for RNA normalisation
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