39 research outputs found

    T-SP1: a novel serine protease-like protein predominantly expressed in testis

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    Here, we describe a novel member in the group of membrane-anchored chymotrypsin (S1)-like serine proteases, namely testis serine protease 1 (T-SP1), as it is principally expressed in testis tissue. The human T-SP1 gene encompasses 28.7 kb on the short arm of chromosome 8 and consists of seven exons. Rapid amplification of cDNA ends ( RACE) experiments revealed that due to alternative splicing three different variants (T-SP1/1, -2, -3) are detectable in testis tissue displaying pronounced heterogeneity at their 3'-end. T-SP1/1 consists of an 18 amino acid signal peptide and of a 49 amino acid propeptide. The following domain with the catalytic triad of His(108), Asp(156), and Ser(250) shares sequence identities of 42% and 40% with the blood coagulation factor XI and plasma kallikrein, respectively. Only T-SP1/1 contains a hydrophobic part at the C-terminus, which provides the basis for cell membrane anchoring. Using a newly generated polyclonal anti-T-SP1 antibody, expression of the T-SP1 protein was found in the Leydig and Sertoli cells of the testis and in the epithelial cells of the ductuli efferentes. Notably, T-SP1 protein was also detectable in prostate cancer and in some ovarian cancer tissues, indicating tumor-related synthesis of T-SP1 beyond testis tissue

    Experimental determination of barium isotope fractionation during diffusion and adsorption processes at low temperatures

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    Variations in barium (Ba) stable isotope abundances measured in low and high temperature environments have recently received increasing attention. The actual processes controlling Ba isotope fractionation, however, remain mostly elusive. In this study, we present the first experimental approach to quantity the contribution of diffusion and adsorption on mass-dependent Ba isotope fractionation during transport of aqueous Ba²+ ions through a porous medium. Experiments have been carried out in which a BaCl₂ solution of known isotopic composition diffused through u-shaped glass tubes filled with silica hydrogel at 10 °C and 25 °C for up to 201 days. The diffused Ba was highly fractionated by up to -2.15 ‰ in δ¹³⁷⁄¹³⁴Ba, despite its high atomic mass. The time-dependent isotope fractionation can be successfully reproduced by a diffusive transport model accounting for mass-dependent differences in the effective diffusivities of the Ba isotope species (D₁₃₇Ba ⁄D₁₃₄Ba =(m₁₃₄⁄m₁₃₇ )β ). Values of β extracted from the transport model were in the range of 0.010 to 0.011. Independently conducted batch experiments revealed that adsorption of Ba onto the surface of silica hydrogel favoured the heavier Ba isotopes (α = 1.00015 ± 0.00008). The contribution of adsorption on the overall isotope fractionation in the diffusion experiments, however, was found to be small. Our results contribute to the understanding of Ba isotope fractionation processes, which is crucial for interpreting natural isotope variations and the assessment of Ba isotope ratios as geochemical proxies

    Skill metrics for confronting global upper ocean ecosystem-biogeochemistry models against field and remote sensing data

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    Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 76 (2009): 95-112, doi:10.1016/j.jmarsys.2008.05.015.We present a generalized framework for assessing the skill of global upper ocean ecosystem-biogeochemical models against in-situ field data and satellite observations. We illustrate the approach utilizing a multi-decade (1979-2004) hindcast experiment conducted with the Community Climate System Model (CCSM-3) ocean carbon model. The CCSM-3 ocean carbon model incorporates a multi-nutrient, multi-phytoplankton functional group ecosystem module coupled with a carbon, oxygen, nitrogen, phosphorus, silicon, and iron biogeochemistry module embedded in a global, threedimensional ocean general circulation model. The model is forced with physical climate forcing from atmospheric reanalysis and satellite data products and time-varying atmospheric dust deposition. Data-based skill metrics are used to evaluate the simulated time-mean spatial patterns, seasonal cycle amplitude and phase, and subannual to interannual variability. Evaluation data include: sea surface temperature and mixed layer depth; satellite derived surface ocean chlorophyll, primary productivity, phytoplankton growth rate and carbon biomass; large-scale climatologies of surface nutrients, pCO2, and air-sea CO2 and O2 flux; and time-series data from the Joint Global Ocean Flux Study (JGOFS). Where the data is sufficient, we construct quantitative skill metrics using: model-data residuals, time-space correlation, root mean square error, and Taylor diagrams.This work was supported in part by grants from the NSF/ONR National Ocean Partnership Program (N000140210370), the NASA Ocean Biology and Biogeochemistry Program (NNX07AL80G), and the NSF Center for Microbial Oceanography Research and Education (C-MORE)

    an association between diversity and exoticism

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    Focusing on contemporary Iranian artists and intellectuals, I examine the creation of collective identifications from an internal perspective. Drawing on research on migrant associations and ethnic and racial boundaries in Germany, the ethnographic account alternates between internal relations, member's participation in the transnational field of Iranian artists, and representative activities in the German public sphere. It explains how the members' unequal resources and varying politics of value caused a shift in the association's system of value. From a critique of assimilationism and the promotion of the value of diversity, the group came to largely comply with the system of value prevailing in the German public sphere, sustained by its intersection with the one that shapes the transnational social field of Iranian artists

    Resistance post-Occupy. A cultural criminological analysis of resistance, knowledge production and imagination in the radical movement in New York City

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    Based on a critical ethnographic study, the present work explores understandings of resistance, power and social change among activists in the post-Occupy movement in New York City. The research asks how activists understand, experience and define resistance in relation to power and social change, and explores the meaning of resistance for those engaged in it. Here, the research focusses in particular on anarchist and anarchist-inspired resistance, or direct action politics. It analyses how the principles and tactics of direct action are defined by activists; and asks, in consideration of spatio-temporal dimensions (immediacy and future-orientation, and separation and confrontation), what constitutes direct action as 'resistance'. Furthermore, this analysis starts from the assumption that tracing down the relationship between ontology, epistemology and methodology in movement activity allows for the development of an understanding of how shared experiences and conceptions of social reality and social change influence activists' resistant practices. Here, the research asks how resistant practice and theory is shaped in the post-Occupy movement's collective processes of knowledge production and through their large variety of knowledge practices. These are characterized by the interplay between theory and practice - by 'doing resistance' in as much as reflecting, discussing, and negotiating - that aims to achieve a radical (re-)imagination of what it means to be and act political. The work situates both collective processes of knowledge production and activists' conceptualizations of resistance within the (recent) history of New York City's social movements, and within conflicts around housing and gentrification, which have been identified as core struggles of the post-Occupy movement. Here, the research shows how activists' conceptualizations of resistance, power and social change are implemented in concrete resistant practices in the city using a variety of examples, among them the work of the New York City Anti-Eviction Network (NYCAEN). Theoretically, the research utilizes an interdisciplinary approach, while focusing on a combination of anarchist philosophy and cultural criminology. Here, the research aims to contribute to current debates in cultural criminology that seek increased theoretical and analytical clarity of the concept of 'resistance'. It is argued that the analysis of the methods of resistance employed, and discussed, in the post-Occupy movement helps to understand and conceptualize resistance in cultural criminology by linking activists' own theorizing with academic theorizing. This also allows for a re-consideration of the influence of anarchist philosophy on cultural criminological understandings of resistance, which contributes to necessary theoretical clarifications while at the same time challenging the criticism that cultural criminology suffers from a general failure to consider political resistance in its theory and research

    Verfahren zur Isolierung von Neuronen

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    Excess radiocarbon constraints on air-sea gas exchange and the uptake of CO 2 by the oceans

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    International audienceWe reassess the constraints that estimates of the global ocean excess radiocarbon inventory (I E) place on air-sea gas exchange. We find that the gas exchange scaling parameter a q cannot be constrained by I E alone. Non-negligible biases in different global wind speed data sets require a careful adaptation of a q to the wind field chosen. Furthermore, a q depends on the spatial and temporal resolution of the wind fields. We develop a new wind speed-and inventory-normalized gas exchange parameter a q N which takes into account these biases and which is easily adaptable to any new estimate of I E. Our study yields an average estimate of a q of 0.32 ± 0.05 for monthly mean winds, lower than the previous estimate (0.39) from Wanninkhof (1992). We calculate a global annual average piston velocity for CO 2 of 16.7 ± 2.9 cm/hr and a gross CO 2 flux between atmosphere and ocean of 73 ± 10 PgC/yr, significantly lower than results from previous studies
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