1,530 research outputs found

    Spin 3 cubic vertices in a frame-like formalism

    Full text link
    Till now most of the results on interaction vertices for massless higher spin fields were obtained in a metric-like formalism using completely symmetric (spin-)tensors. In this, the Lagrangians turn out to be very complicated and the main reason is that the higher the spin one want to consider the more derivatives one has to introduce. In this paper we show that such investigations can be greatly simplified if one works in a frame-like formalism. As an illustration we consider massless spin 3 particle and reconstruct a number of vertices describing its interactions with lower spin 2, 1 and 0 ones. In all cases considered we give explicit expressions for the Lagrangians and gauge transformations and check that the algebra of gauge transformations is indeed closed.Comment: 17 pades, no figure

    Improved harmony search methods to replace variational principle in geotechnical problems

    Get PDF
    2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Archaeobotanical and GIS-based approaches to prehistoric agriculture in the upper Ying valley, Henan, China

    Get PDF
    Archaeobotanical survey has sampled a series of late Neolithic to early Bronze Age settlements in the upper Ying valley (part of the central plain of China) and provided useful data for understanding prehistoric arable ecology and farming during a period of increasing local social complexity. A combination of the modelling functions offered by Geographic Information Systems (GIS) and the data reduction possibilities offered by Principal Component Analysis (PCA) allow us to explore possible relationships between local arable ecology, crop-processing strategies and the natural environment. The results should be treated cautiously given the size of the analytical sample but suggest that differences in the natural environment around each site may explain varying patterns of wild food collection, while social and cultural factors may better explain variation in farming practice and crop-processing at different sites. (C) 2010 Elsevier Ltd. All rights reserved

    The reactive metabolite target protein database (TPDB) – a web-accessible resource

    Get PDF
    BACKGROUND: The toxic effects of many simple organic compounds stem from their biotransformation to chemically reactive metabolites which bind covalently to cellular proteins. To understand the mechanisms of cytotoxic responses it may be important to know which proteins become adducted and whether some may be common targets of multiple toxins. The literature of this field is widely scattered but expanding rapidly, suggesting the need for a comprehensive, searchable database of reactive metabolite target proteins. DESCRIPTION: The Reactive Metabolite Target Protein Database (TPDB) is a comprehensive, curated, searchable, documented compilation of publicly available information on the protein targets of reactive metabolites of 18 well-studied chemicals and drugs of known toxicity. TPDB software enables i) string searches for author names and proteins names/synonyms, ii) more complex searches by selecting chemical compound, animal species, target tissue and protein names/synonyms from pull-down menus, and iii) commonality searches over multiple chemicals. Tabulated search results provide information, references and links to other databases. CONCLUSION: The TPDB is a unique on-line compilation of information on the covalent modification of cellular proteins by reactive metabolites of chemicals and drugs. Its comprehensiveness and searchability should facilitate the elucidation of mechanisms of reactive metabolite toxicity. The database is freely available a

    Occurrence of red clay horizon in soil profiles of the Yellow River Delta: Implications for accumulation of heavy metals

    Get PDF
    The source-area weathering and pedogenesis processes in the alluvial soil profiles might affect depth distribution of heavy metals. Red clay horizon (RCH) with a thickness of 5-50 cm in a 1 m soil profile has been found ubiquitously in the Yellow River Delta (YRD). The occurrence of this RCH was supposed to be related with the frequent shifting of the Yellow River tail channel in the Yellow River Delta (YRD). The geochemical features of the RCH were distinct from its upper or lower yellow silt horizon (YSH). The average median grain size of the RCH (10.5 pm) was almost three times lower than that of the YSH (29.9 mu m). Meanwhile, the RCH was characterized of higher chemical index of alteration (CIA), magnetic susceptibility (chi(lf)) and frequency-dependent magnetic susceptibility (chi(fd)) values than the YSH, which implied a stronger source-area weathering and pedogenesis intensity of the RCH. Besides the distinctive characteristics of the RCH, it also accumulated significantly (p < 0.05) higher mean contents of Cu, Zn, Pb, Cr, Ni and Co, and maximum content of Cd in the RCH than that in the YSH. The principal component analysis (PCA) suggested that distribution of the heavy metals in the YRD soil profiles was significantly related to the content of aluminosilicates, oxides, clay fraction, chi(lf) and chi(fd), however, such a correlation was not found except for Pb in the YSH. In addition, result of BCR sequential extraction indicated that a higher percentage of Fe-Mn oxides associated fraction was in the RCH than in the YSH for the heavy metals of Pb and Co. Cadmium was observed at higher percentage of exchangeable fraction in the RCH than in the YSH, implying a higher environmental risk of the Cd in the RCH. (C) 2015 Elsevier B.V. All rights reserved

    Calcium Uptake and Proton Transport by Acidocalcisomes of Toxoplasma gondii

    Get PDF
    Acidocalcisomes are acidic calcium stores found in diverse organisms, being conserved from bacteria to humans. They possess an acidic matrix that contains several cations bound to phosphates, which are mainly present in the form of short and long polyphosphate chains. Their matrix is acidified through the action of proton pumps such as a vacuolar proton ATPase and a vacuolar proton pyrophosphatase. Calcium uptake occurs through a Ca2+/H+ countertransporting ATPase located in the membrane of the organelle. Acidocalcisomes have been identified in a variety of microorganisms, including Apicomplexan parasites such as Plasmodium and Eimeria species, and in Toxoplasma gondii. We report the purification and characterization of an acidocalcisome fraction from T. gondii tachyzoites after subcellular fractionation and further discontinuous iodixanol gradient purification. Proton and calcium transport activities in the fraction were characterized by fluorescence microscopy and spectrophotometric methods using acridine orange and arsenazo III, respectively. This work will facilitate the understanding of the function of acidocalcisomes in Apicomplexan parasites, as we can now isolate highly purified fractions that could be used for proteomic analysis to find proteins that may clarify the biogenesis of these organelles

    Y-chromosomal STRs haplotypes in the Taiwanese Paiwan population

    Get PDF
    The distribution of Y-chromosomal short tandem repeat (Y-STR) haplotypes was determined in a population of Taiwanese Paiwan aboriginals. Using 17 Y-STR markers, a total of 135 haplotypes were observed, 102 of which were unique. The overall haplotype diversity for the 17 Y-STR loci tested was 0.9922 and the discrimination capacity was 0.6490. In addition, three novel intermediate alleles at the DYS448 locus were also found

    Long-Term Mortality of Patients with Septic Ocular or Central Nervous System Complications from Pyogenic Liver Abscess: A Population-Based Study

    Get PDF
    Background: Taiwan is endemic for pyogenic liver abscess (PLA). Septic ocular or central nervous system (CNS) complications derived from PLA can result in catastrophic disability. We investigated the epidemiology and long-term prognosis of PLA patients with septic ocular or CNS complications over an 8-year period. Methodology/Principal Findings: We extracted 21,307 patients with newly diagnosed PLA from a nationwide health registry in Taiwan between 2000 and 2007. The frequency of and risk factors for PLA with septic ocular or CNS complications were determined. The 2-year survival of these patients was compared between those with and without septic ocular or CNS complications. Septic ocular or CNS complications accounted for 2.1 % of all PLA patients. Age and the Charlson comorbidity index were significantly lower in PLA patients with ocular or CNS complications than those without. Diabetes and age,65 years were independent predictors of septic ocular or CNS complications. The 2-year mortality of patients with septic ocular or CNS complications was similar to those without complications (24.8 % vs. 27.5%, p = 0.502). However, among patients,65 years old and a Charlson index #1, the 2-year mortality was significantly higher in those with than without complications (18.6 % vs. 11.8%, p = 0.001). Conclusions/Significance: Physicians should recognize that catastrophic disability due to ocular or neurologica
    corecore