Sediment-water exchange in shallow water estuarine sediments

Pore water profiles in shallow estuarine sediments of Puget Sound show the characteristics of enhanced interstitial-water transport by animal activity. Using an in situ 3H experiment and dissolved silicate profiles we evaluate the transport parameter due to animal activity in the surface 20 cm of sediments to be 1–5 × 10–7 s–1 which is in the range of similar parameters determined in other nearshore environments in the U.S. The fluxes of alkalinity, ammonia and silicate across the sediment-water interface due to biological processes are greater than that by one-dimensional molecular diffusion. For the metals Fe, Mn, Cu, Ni and Cd the dominant transport mechanism depends upon the depth at which the metal is released to the pore waters. Probably the most important effect of biological activity on metal remobilization is the removal of sulfide from the pore waters, via ventilation of sediments with oxic overlying water, allowing the enrichment of dissolved metals which might otherwise be very low in concentration due to insoluble sulfide formation. The result is a greatly enhanced flux of metals to the bottom waters

Early Years Parenting Mediates Early Adversity Effects on Problem Behaviors in Intellectual Disability

A family developmental framework was applied to data from families of children with intellectual disabilities to understand the role of parenting in the path from early adversity to problem behaviors in mid-childhood. Data from 9 months to 11 years tested the Family Stress Model in families of 555 children. Adversarial parenting between 3 and 5 years mediated the path from early adversity (family poverty and maternal psychological distress at nine months) to problem behaviors at 7 and 11 years. Positive parent-child relationship only mediated the path to conduct problems. Multiple mediation was not present. Early adversity impacts both positive parent-child relationship and adversarial parenting between three and five, but the latter is crucial for problem behaviors in mid-childhood

14-11 Travel in Adverse Winter Weather Conditions by Blind Pedestrians

Winter weather creates many orientation and mobility (O&M) challenges for people who are visually impaired. Getting the cane tip stuck is one of the noticeable challenges when traveling in snow, particularly when the walking surface is covered in deep snow. We compared four different cane tips: 1) metal glide, 2) marshmallow roller, 3) roller ball, and 4) bundu bahser. There was a statistically significant difference in frequency of sticking among the different cane tips. Post hoc analyses revealed that the sticking frequency for the metal glide tip was significantly higher than that for the roller ball tip, for the bundu basher tip, and for the marshmallow roller tip. In addition, there was a statistically significant difference in sticking frequency between the marshmallow roller tip and the roller ball tip. Cane tip shape appears to have contributed to differences in sticking frequency. For example, the metal glide tip, being the smallest and more sharply angled among the four cane tips, tended to get stuck on snow more often than more rounded and larger cane tips. Differences in sticking frequency among the cane tips observed in this study appear to be large enough to be practically significant for cane users and practitioners

Towards a fundamental astrometric reference system behind the Malleganic clouds : spectroscopic confirmation of new quasar candidates selected in the near-infrared

Quasi-stellar objects (quasars) located behind nearby galaxies provide an excellent absolute reference system for astrometric studies, but they are difficult to identify because of fore- and background contamination. We have embarked on a programme to expand the quasar reference system behind the Large and Small Magellanic Clouds, the Magellanic Bridge and Magellanic Stream. Hundreds of quasar candidates were selected, based on their near-infrared colours and variability properties from the ESO VISTA Magellanic Clouds (VMC) Public Survey. A subset of 49 objects was followed up with optical spectroscopy with FORS2. We confirmed the quasar nature of 37 objects (34 new identifications) that span a redshift range from z ~ 0.5 to 4.1

Conventional and regulatory CD4+ T cells that share identical TCRs are derived from common clones

Results from studies comparing the diversity and specificity of the TCR repertoires expressed by conventional (Tconv) and regulatory (Treg) CD4+ T cell have varied depending on the experimental system employed. We developed a new model in which T cells express a single fixed TCRα chain, randomly rearranged endogenous TCRβ chains, and a Foxp3-GFP reporter. We purified CD4+Foxp3- and CD4+Foxp3+ cells, then performed biased controlled multiplex PCR and high throughput sequencing of endogenous TCRβ chains. We identified >7,000 different TCRβ sequences in the periphery of 5 individual mice. On average, ~12% of TCR sequences were expressed by both conventional and regulatory populations within individual mice. The CD4+ T cells that expressed shared TCR sequences were present at higher frequencies compared to T cells expressing non-shared TCRs. Furthermore, nearly all (>90%) of the TCR sequences that were shared within mice were identical at the DNA sequence level, indicating that conventional and regulatory T cells that express shared TCRs are derived from common clones. Analysis of TCR repertoire overlap in the thymus reveals that a large proportion of Tconv and Treg sharing observed in the periphery is due to clonal expansion in the thymus. Together these data show that there are a limited number of TCR sequences shared between Tconv and Tregs. Also, Tconv and Tregs sharing identical TCRs are found at relatively high frequencies and are derived from common progenitors, of which a large portion are generated in the thymus