341 research outputs found

    Religiosity and the motivation for social affiliation

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    Although universal, the motivation to affiliate can vary as a function of individual differences and of the characteristics of the target. Three studies explored the extent to which religious beliefs and identity are related to social affiliation motivation. Because most religions advocate affiliation and provide opportunities for frequent experiences of affiliation, we reasoned that religious people might show greater affiliation motivation in everyday attitudes and behaviors. We found that religiosity was positively related to implicit and behavioral measures of general social affiliation (Studies 1 and 2). However, manipulating the identity of the affiliation target revealed that when affiliating might not lead to positive outcomes, the relation between religiosity and social affiliation disappeared (but did not reverse). In Studies 2 and 3, when the target of the affiliation was explicitly identified as a member of a threatening out-group (atheist), religiosity did not predict affiliation behaviors. We discuss the mechanisms by which religiosity motivates and constrains social affiliation and the potential implications for social influence and intergroup processes

    Effects of oxytocin administration on spirituality and emotional responses to meditation

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    The oxytocin (OT) system, critically involved in social bonding, may also impinge on spirituality, which is the belief in a meaningful life imbued with a sense of connection to a Higher Power and/or the world. Midlife male participants (N = 83) were randomly assigned to receive intranasal OT or placebo. In exploratory analyses, participants were also genotyped for polymorphisms in two genes critical for OT signaling, the oxytocin receptor gene (OXTR rs53576) and CD38 (rs6449182 and rs3796863). Results showed that intranasal OT increased self-reported spirituality on two separate measures and this effect remained significant a week later. It also boosted participants’ experience of specific positive emotions during meditation, at both explicit and implicit levels. Furthermore, the effect of OT on spirituality was moderated by OT-related genotypes. These results provide the first experimental evidence that spirituality, endorsed by millions worldwide, appears to be supported by OT

    Specific dose-dependent effects of ethane 1,2-dimethanesulfonate in rat and mouse Leydig cells and non-steroidogenic cells on programmed cell death

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    The mechanism by which ethane 1,2-dimethanesulfonate (EDS) selectively kills Leydig cells is poorly understood. To characterize further the cell-specific actions of EDS, we studied biochemical and morphological changes during apoptosis in different Leydig cell and non-steroidogenic cell models.Rat testicular and H540 tumor Leydig cells were killed by 1-2 mM EDS, whereas 20 mM EDS were required for MA-10 cells. This higher concentration of EDS was also necessary for activation of apoptosis in non-steroidogenic Chinese hamster ovary cells, whereas COS-1 monkey kidney cells were resistant. These variable effects of EDS on apoptosis were independent of new protein synthesis and, interestingly, could be delayed by co-incubation with dibutyrl cyclic AMP. Along with cell death, we also observed chromosomal fragmentation and other hallmarks indicative of apoptosis as evidenced by DNA laddering and fluorescent microscopy. Time-lapse photography with a confocal microscope showed that the time of onset, duration and even the sequence of apoptotic events between individual H540 cells was heterogeneous. When the dose of EDS was gradually increased from 2 to 10 mM, the proportion of cells showing normal apoptotic features gradually decreased. Intriguingly, treatment with 10 mM EDS did not result in death for most cells and was marked by an absence of DNA laddering and ultrastructural features of apoptosis and necrosis. However, incubation with 20 mM EDS resulted in necrosis.These results demonstrated that the effects of EDS on cell survival are not specific to Leydig cells, that different cell types have different sensitivities to EDS and that stimulation of the cAMP pathway may mitigate EDS action. The data obtained with H540 cells further revealed that EDS can induce two types of programmed cell death

    Arsenite sorption and co-precipitation with calcite

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    Sorption of As(III) by calcite was investigated as a function of As(III) concentration, time and pH. The sorption isotherm, i.e. the log As(III) vs. log [As(OH)3 degrees / Assat] plot is S-shaped and has been modelled on an extended version of the surface precipitation model. At low concentrations, As(OH)3 degrees is adsorbed by complexation to surface Ca surface sites, as previously described by the X-ray standing wave technique. The inflexion point of the isotherm, where As(OH)3 degrees is limited by the amount of surface sites (ST), yields 6 sites nm-2 in good agreement with crystallographic data. Beyond this value, the amount of sorbed arsenic increases linearly with solution concentration, up to the saturation of arsenic with respect to the precipitation of CaHAsO3(s). The solid solutions formed in this concentration range were examined by X-ray and neutron diffraction. The doped calcite lattice parameters increase with arsenic content while c/a ratio remains constant. Our results made on bulk calcite on the atomic displacement of As atoms along [0001] direction extend those published by Cheng et al., (1999) on calcite surface. This study provides a molecular-level explanation for why As(III) is trapped by calcite in industrial treatments.Comment: 9 page

    APERTIF, a focal plane array for the WSRT

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    In this paper we describe a focal plane array (FPA) prototype, based on Vivaldi elements, developed for the Westerbork Synthesis Radio Telescope (WSRT) to increase its instantaneous field of view by a factor 25 and double its current bandwidth. This prototype is the first step in a project that has the ambition to equip most of the WSRT antennas with FPAs to improve the survey speed of the telescope. Examples of scientific applications are surveys of the northern sky in polarised continuum and HI emission, and efficient searches for pulsars and transients.Comment: 7 pages, 6 figures. Presented at "The Evolution of Galaxies through the Neutral Hydrogen Window", Feb 1-3, 2008, Arecibo Observatory, Puerto Rico. High resolution versions of figures available in jpg-forma

    A diagnostic approach to constraining flow partitioning in hydrologic models using a multiobjective optimization framework

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    © American Geophysical Union: Shafii, M., Basu, N., Craig, J. R., Schiff, S. L., & Van Cappellen, P. (2017). A diagnostic approach to constraining flow partitioning in hydrologic models using a multiobjective optimization framework. Water Resources Research, 53(4), 3279–3301. https://doi.org/10.1002/2016WR019736Hydrologic models are often tasked with replicating historical hydrographs but may do so without accurately reproducing the internal hydrological functioning of the watershed, including the flow partitioning, which is critical for predicting solute movement through the catchment. Here we propose a novel partitioning-focused calibration technique that utilizes flow-partitioning coefficients developed based on the pioneering work of L'vovich (1979). Our hypothesis is that inclusion of the L'vovich partitioning relations in calibration increases model consistency and parameter identifiability and leads to superior model performance with respect to flow partitioning than using traditional hydrological signatures (e.g., flow duration curve indices) alone. The L'vovich approach partitions the annual precipitation into four components (quick flow, soil wetting, slow flow, and evapotranspiration) and has been shown to work across a range of climatic and landscape settings. A new diagnostic multicriteria model calibration methodology is proposed that first quantifies four calibration measures for watershed functions based on the L'vovich theory, and then utilizes them as calibration criteria. The proposed approach is compared with a traditional hydrologic signature-based calibration for two conceptual bucket models. Results reveal that the proposed approach not only improves flow partitioning in the model compared to signature-based calibration but is also capable of diagnosing flow-partitioning inaccuracy and suggesting relevant model improvements. Furthermore, the proposed partitioning-based calibration approach is shown to increase parameter identifiability. This model calibration approach can be readily applied to other models. Plain Language Summary Hydrologic models are often tasked with replicating historical hydrographs but may do so without accurately reproducing the internal hydrological functioning of the watershed, including the flow partitioning between low and high flows, which is critical for predicting solute movement through the catchment. Here we propose a novel model calibration framework that utilizes an empirical understanding about flow partitioning developed by L'vovich (1979) to constrain the outcomes of watershed models. Our hypothesis is that this approach increases model consistency leads to superior model performance. This method is also capable of diagnosing model structural errors (in flow partitioning) and suggesting relevant model improvements. Overall, this work is a step toward getting the right answer from hydrologic model for the right reasons.NSERC Strategic Partnership grant [STPGP-447692-2013]Canada Excellence Research Chair in Ecohydrology in the Department of Earth and Environmental Sciences at University of Waterlo

    Structure of peat soils and implications for water storage, flow and solute transport: A review update for geochemists

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    Global peatlands are a valuable but vulnerable resource. They represent a significant carbon and energy reservoir and play major roles in water and biogeochemical cycles. Peat soils are highly complex porous media with distinct characteristic physical and hydraulic properties. Pore sizes in undecomposed peat can exceed 5 mm, but significant shrinkage occurs during dewatering, compression and decomposition, reducing pore-sizes. The structure of peat soil consists of pores that are open and connected, dead-ended or isolated. The resulting dual-porosity nature of peat soils affects water flow and solute migration, which influence reactive transport processes and biogeochemical functions. Advective movement of aqueous and colloidal species is restricted to the hydrologically active (or mobile) fraction of the total porosity, i.e. the open and connected pores. Peat may attenuate solute migration through molecular diffusion into the closed and dead-end pores, and for reactive species, also through sorption and degradation reactions. Slow, diffusion-limited solute exchanges between the mobile and immobile regions may give rise to pore-scale chemical gradients and heterogeneous distributions of microbial habitats and activity in peat soils. While new information on the diversity and functionalities of peat microbial communities is rapidly accumulating, the significance of the geochemical and geomicrobial study on peat stands to benefit from a basic understanding of the physical structure of peat soils. In this paper, we review the current knowledge of key physical and hydraulic properties related to the structure of globally available peat soils and briefly discuss their implications for water storage, flow and the migration of solutes. This paper is intended to narrow the gap between the ecohydrological and biogeochemical research communities working on peat soils.Canada Excellence Research Chair (CERC) progra

    Silencing markers are retained on pericentric heterochromatin during murine primordial germ cell development

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    Background: In the nuclei of most mammalian cells, pericentric heterochromatin is characterized by DNA methylation, histone modifications such as H3K9me3 and H4K20me3, and specific binding proteins l

    Cellular dosimetry of [177Lu]Lu-DOTA-[Tyr3]octreotate radionuclide therapy: the impact of modeling assumptions on the correlation with in vitro cytotoxicity

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    Background: Survival and linear-quadratic model fitting parameters implemented in treatment planning for targeted radionuclide therapy depend on accurate cellular dosimetry. Therefore, we have built a refined cellular dosimetry model for [177Lu]Lu-DOTA-[Tyr3]octreotate (177Lu-DOTATATE) in vitro experiments, accounting for specific cell morphologies and sub-cellular radioactivity distributions. Methods: Time activity curves were measured and modeled for medium, membrane-bound, and internalized activity fractions over 6 days. Clonogenic survival assays were performed at various added activities (0.1–2.5 MBq/ml). 3D microscopy images (stained for cytoplasm, nucleus, and Golgi) were used as reference for developing polygonal meshes (PM) in 3DsMax to accurately render the cellular and organelle geometry. Absorbed doses to the nucleus per decay (S values) were calculated for 3 cellular morphologies: spheres (MIRDcell), truncated cone-shaped constructive solid geometry (CSG within MCNP6.1), and realistic PM models, using Geant4-10.03. The geometrical set-up of the clonogenic survival assays was modeled, including dynamic changes in proliferation, proximity variations, and cell death. The absorbed dose to the nucleus by the radioactive source cell (self-dose) and surrounding source cells (cross-dose) was calculated applying the MIRD formalism. Finally, the correlation between absorbed dose and survival fraction was fitted using a linear dose-response curve (high α/β or fast sub-lethal damage repair half-life) for different assumptions, related to cellular sha
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