Modes of sea-water intrusion during transgression.

Analytical methods and numerical experiments are used to study salinization of groundwater in response to sea level rise. The system that is studied involves a saturated porous medium with an inclined upper surface. The upper surface is progressively inundated during sea level rise to simulate transgression, the landward migration of the shoreline. Four "modes" of seawater intrusion are distinguished: (1) horizontal intrusion for slow transgression and a relatively high-permeability (sand/silt) substrate, (2) vertical intrusion by seawater fingering for fast transgression and a sand/silt substrate, (3) vertical intrusion by diffusion for fast transgression and a low-permeability (clay) substrate, (4) vertical intrusion by combined diffusion and low-salinity fingering for fast transgression and a clay layer at the seafloor overlying an aquifer. These four modes are characterized by the development of very distinctive transition zones between the fresh and salt groundwater domains. An analytical expression is derived for the critical transgression rate which separates horizontal (mode 1) from dominantly vertical (modes 2-4) intrusion. For modes 3 and 4, salinization significantly lags behind sea level rise. The results are consistent with observations of fossil fresh/brackish groundwater beneath many continental shelves and shallow seas

The composition and role of convergent technological repertoires in audiovisual media consumption

This mixed-method research focuses on the growing appropriation of multiple screen devices for audiovisual media consumption. Based on survey measures, we distinguish three patterns: (a) maintaining the status quo, by mainly drawing upon television, (b) broadening up the repertoire, by extending television with computers and mobile devices, or (c) even replacing television by a computer. Next, we draw upon insights from niche theory, rationalising media choices in terms of competing gratifications. This perspective is however too one-sided, as our results indicate that habit is a much stronger explanatory variable, especially when a broad range of devices are appropriated. In a follow-up qualitative study, based on Q-methodology, we found that the orientations towards what people seek in audiovisual technologies are only mildly contingent with specific technology appropriation. This problematises the very substance of niches in the audiovisual: as technologies are capable of the same benefits, their discriminating power is declining. Hence, in future applications of niche theory, gratifications and habits of communication modes (what people do with media technologies) should be taken into account, rather than media as tied to a specific technology. Niche theory's core remains, but its applications should be updated to theoretical insights matching the evolving media environment

Female Perpetrators in Internal Child Trafficking in China: An empirical study

Through an empirical study, this article explores the overall profile of female traffickers of children in China and their role and performance in the trafficking processes. Its contribution to the human-trafficking literature lies in its focus on female perpetrators in particular. The article provides an overview of the international literature on female traffickers as well as contemporary knowledge about internal child trafficking in China. Empirical data from incarcerated traffickers suggest that portraying female traffickers as active players of criminal networks obscures the structural problems affecting female child traffickers. The short-term result is that the problems of female offenders are ignored, and the long-term impact is policy making that is disconnected from the lived experiences of an important population. From a gender perspective, this study suggests that female child traffickers are offenders as well as victims of social and gender inequalities in China’s reform era. This study also proposes that internal child trafficking in China should be brought in the international and Anglo-American debates surrounding human trafficking

Friends and Enemies Within: The Roles of Subgroups, Imbalance, and Isolates in Geographically Dispersed Teams

Research regarding geographically dispersed teams (GDTs) is increasingly common and has yielded many insights into how spatio-temporal and socio-demographic factors affect GDT functioning and performance. Largely missing, however, is research on the effects of the basic geographic configuration of GDTs. In this study, we explore the impact of GDT configuration (i.e., the relative number of team members at different sites, independent of the characteristics of those members or the spatial and temporal distances among them) on GDT dynamics. In a quasi-experimental setting, we examine the effects of configuration using a sample of 62 six-person teams in four different one- and twosite configurations. As predicted, we find that configuration significantly affects team dynamics – independent of spatio-temporal distance and socio-demographic factors. More specifically, we find that teams with geographically-based subgroups (defined as two or more members per site) have significantly less shared team identity, less effective transactive memory, more conflict, and more coordination issues. Furthermore, in teams with subgroups, imbalance (i.e., the uneven distribution of members across sites) exacerbates these effects; subgroups with a numerical minority of team members report significantly poorer scores on the same four outcomes. In contrast, teams with geographically isolated members (i.e., members who have no teammates at their site) outperform both balanced and imbalanced configurations

Insights on geochemical cycling of U, Re and Mo from seasonal sampling in Boston Harbor, Massachusetts, USA

Author Posting. © The Author(s), 2006. 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 Geochimica et Cosmochimica Acta 71 (2007): 895-917, doi:10.1016/j.gca.2006.10.016.This study examined the removal of U, Mo, and Re from seawater by sedimentary processes at a shallow-water site with near-saturation bottom water O2 levels (240-380 μmol O2/L), very high organic matter oxidation rates (annually averaged rate is 870 μmol C/cm2/y), and shallow oxygen penetration depths (4 mm or less throughout the year). Under these conditions, U, Mo, and Re were removed rapidly to asymptotic pore water concentrations of 2.2–3.3 nmol/kg (U), 7–13 nmol/kg (Mo), and 11–14 pmol/kg (Re). The order in which the three metals were removed, determined by fitting a diffusion-reaction model to measured profiles, was Re < U < Mo. Model fits also suggest that the Mo profiles clearly showed the presence of a near-interface layer in which Mo was added to pore waters by remineralization of a solid phase. The importance of this solid phase source of pore water Mo increased from January to October as the organic matter oxidation rate increased, bottom water O2 decreased, and the O2 penetration depth decreased. Experiments with in situ benthic flux chambers generally showed fluxes of U and Mo into the sediments. However, when the overlying water O2 concentration in the chambers was allowed to drop to very low levels, Mn and Fe were released to the overlying water along with the simultaneous release of Mo and U. These experiments suggest that remineralization of Mn and/or Fe oxides may be a source of Mo and perhaps U to pore waters, and may complicate the accumulation of U and Mo in bioturbated sediments with high organic matter oxidation rates and shallow O2 penetration depths. Benthic chamber experiments including the nonreactive solute tracer, Br-, indicated that sediment irrigation was very important to solute exchange at the study site. The enhancement of sediment-seawater exchange due to irrigation was determined for the nonreactive tracer (Br-), TCO2, NH4 +, U and Mo. The comparisons between these solutes showed that reactions within and around the burrows were very important for modulating the Mo flux, but less important for U. The effect of these reactions on Mo exchange was highly variable, enhancing Mo (and, to a lesser extent, U) uptake at times of relatively modest irrigation, but inhibiting exchange when irrigation rates were faster. These results reinforce the observation that Mo can be released to and removed from pore waters via sedimentary reactions. The removal rate of U and Mo from seawater by sedimentary reactions was found to agree with the rate of accumulation of authigenic U and Mo in the solid phase. The fluxes of U and Mo determined by in situ benthic flux chamber measurements were the largest that have been measured to date. These results confirm that removal of redoxsensitive metals from continental margin sediments underlying oxic bottom water is important, and suggest that continental margin sediments play a key role in the marine budgets of these metals.We appreciate the financial support from the National Science Foundation (OCE-0220892). Funding for this work was also provided to JLM by the Postdoctoral Scholar Program at WHOI courtesy of the Cabot Marine Environmental Science Fund and the J. Seward Johnson Fund. Financial support to IMK was given by The Swedish Foundation for International Cooperation in Research and Higher Education

Meiosis in Mice without a Synaptonemal Complex

The synaptonemal complex (SC) promotes fusion of the homologous chromosomes (synapsis) and crossover recombination events during meiosis. The SC displays an extensive structural conservation between species; however, a few organisms lack SC and execute meiotic process in a SC-independent manner. To clarify the SC function in mammals, we have generated a mutant mouse strain (Sycp1−/−Sycp3−/−, here called SC-null) in which all known SC proteins have been displaced from meiotic chromosomes. While transmission electron microscopy failed to identify any remnants of the SC in SC-null spermatocytes, neither formation of the cohesion axes nor attachment of the chromosomes to the nuclear membrane was perturbed. Furthermore, the meiotic chromosomes in SC-null meiocytes achieved pre-synaptic pairing, underwent early homologous recombination events and sustained a residual crossover formation. In contrast, in SC-null meiocytes synapsis and MLH1-MLH3-dependent crossovers maturation were abolished, whereas the structural integrity of chromosomes was drastically impaired. The variable consequences that SC inactivation has on the meiotic process in different organisms, together with the absence of SC in some unrelated species, imply that the SC could have originated independently in different taxonomic groups

Long term records of erosional change from marine ferromanganese crusts

Ferromanganese crusts from the Atlantic, Indian and Pacific Oceans record the Nd and Pb isotope compositions of the water masses from which they form as hydrogenous precipitates. The10Be/9Be-calibrated time series for crusts are compared to estimates based on Co-contents, from which the equatorial Pacific crusts studied are inferred to have recorded ca. 60 Ma of Pacific deep water history. Time series of ɛNd show that the oceans have maintained a strong provinciality in Nd isotopic composition, determined by terrigenous inputs, over periods of up to 60 Ma. Superimposed on the distinct basin-specific signatures are variations in Nd and Pb isotope time series which have been particularly marked over the last 5 Ma. It is shown that changes in erosional inputs, particularly associated with Himalayan uplift and the northern hemisphere glaciation have influenced Indian and Atlantic Ocean deep water isotopic compositions respectively. There is no evidence so far for an imprint of the final closure of the Panama Isthmus on the Pb and Nd isotopic composition in either Atlantic or Pacific deep water masses

corona Is Required for Higher-Order Assembly of Transverse Filaments into Full-Length Synaptonemal Complex in Drosophila Oocytes

The synaptonemal complex (SC) is an intricate structure that forms between homologous chromosomes early during the meiotic prophase, where it mediates homolog pairing interactions and promotes the formation of genetic exchanges. In Drosophila melanogaster, C(3)G protein forms the transverse filaments (TFs) of the SC. The N termini of C(3)G homodimers localize to the Central Element (CE) of the SC, while the C-termini of C(3)G connect the TFs to the chromosomes via associations with the axial elements/lateral elements (AEs/LEs) of the SC. Here, we show that the Drosophila protein Corona (CONA) co-localizes with C(3)G in a mutually dependent fashion and is required for the polymerization of C(3)G into mature thread-like structures, in the context both of paired homologous chromosomes and of C(3)G polycomplexes that lack AEs/LEs. Although AEs assemble in cona oocytes, they exhibit defects that are characteristic of c(3)G mutant oocytes, including failure of AE alignment and synapsis. These results demonstrate that CONA, which does not contain a coiled coil domain, is required for the stable ‘zippering’ of TFs to form the central region of the Drosophila SC. We speculate that CONA's role in SC formation may be similar to that of the mammalian CE proteins SYCE2 and TEX12. However, the observation that AE alignment and pairing occurs in Tex12 and Syce2 mutant meiocytes but not in cona oocytes suggests that the SC plays a more critical role in the stable association of homologs in Drosophila than it does in mammalian cells

Examining the generalizability of research findings from archival data

This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability-for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples

Pathway-Based Analysis of a Melanoma Genome-Wide Association Study: Analysis of Genes Related to Tumour-Immunosuppression

Systemic immunosuppression is a risk factor for melanoma, and sunburn-induced immunosuppression is thought to be causal. Genes in immunosuppression pathways are therefore candidate melanoma-susceptibility genes. If variants within these genes individually have a small effect on disease risk, the association may be undetected in genome-wide association (GWA) studies due to low power to reach a high significance level. Pathway-based approaches have been suggested as a method of incorporating a priori knowledge into the analysis of GWA studies. In this study, the association of 1113 single nucleotide polymorphisms (SNPs) in 43 genes (39 genomic regions) related to immunosuppression have been analysed using a gene-set approach in 1539 melanoma cases and 3917 controls from the GenoMEL consortium GWA study. The association between melanoma susceptibility and the whole set of tumour-immunosuppression genes, and also predefined functional subgroups of genes, was considered. The analysis was based on a measure formed by summing the evidence from the most significant SNP in each gene, and significance was evaluated empirically by case-control label permutation. An association was found between melanoma and the complete set of genes (pemp = 0.002), as well as the subgroups related to the generation of tolerogenic dendritic cells (pemp = 0.006) and secretion of suppressive factors (pemp = 0.0004), thus providing preliminary evidence of involvement of tumour-immunosuppression gene polymorphisms in melanoma susceptibility. The analysis was repeated on a second phase of the GenoMEL study, which showed no evidence of an association. As one of the first attempts to replicate a pathway-level association, our results suggest that low power and heterogeneity may present challenges