Mass mortalities in bivalve populations: A review of the edible cockle Cerastoderma edule (L.)

Mass mortalities in bivalve populations have long been of particular concern, especially when the species supports a commercial fishery or is of conservation interest. Here we consider the evidence of mass mortalities of the edible cockle, Cerastoderma edule (L.). Through the construction of a conceptual model eight potential factors (or groups of factors) which may cause mass mortalities are identified and reviewed. These include: food limitation; density; oxygen depletion and organic loadings; temperature and salinity; parasites, pathogens and commensals; toxicants and other persistent pollutants; predation, and changes in sediment, suspended solids, topography and bathymetry. The interplay between factors in recognized and discussed based on evidence mainly from the published literature relating to temperate edible cockle beds. Anecdotal evidence is also reported from a structured survey of site-specific evidence provided by fisheries managers in England and Wales. Case studies from the UK and Europe indicate that there is often no single, clear generic cause of mass mortalities in cockle populations. The importance of linked site-specific scientific investigations and laboratory-based experiments to fill the gaps in our current understanding of mass mortalities in bivalve species is highlighted as necessary to take account of both local extrinsic and intrinsic factors

Interactive dynamic objects in a virtual light field

National audienceThis report builds upon existing work on Virtual Light Fields (VLF). A previous VLF implementation allows interactive walkthrough of a static globally illuminated scene on a modern desktop computer. This report outlines enhancements to this implementation which allow movable geometry to be added to existing VLF solutions. Two diffuse shading modes are implemented for the dynamic geometry. A fast simple mode which approximates the emitters in the VLF using OpenGL light sources and a slower advanced mode which approximates the diffuse inter-reflection and soft shadows received on the dynamic geometry using information from the VLF. In both modes the dynamic geometry casts hard shadows onto existing diffuse geometry in the scene. Both modes can achieve interactive rates on a high specification modern desktop computer, although advanced mode is limited to simple dynamic objects due to the expensive diffuse gathering step. Potential optimisations are discussed

Numerical Analysis of Residential Electricity Generation Using Solar Thermal Energy

2010 Honda I Dream CompetitionCurrently, the world has an ever increasing energy demand and available resources such as fossil fuels are not a sustainable option for the future. Solar thermal electricity generation is one option to curve this problem, but the technology is currently limited to large utility scale. This thesis explores the fluid selection process and optimization of an Organic Rankine Cycle that could provide the electrical load of a residential home. Four working fluids (R600a/iso-butane, n-pentane, methanol and ethanol) and four system configurations (Rankine with and without superheating, open loop and closed loop pre-heating) were parametrically explored to see if it was feasible to create a system with efficiencies that were competitive with current photovoltaic technology. The results found that for low grade solar heat in the range of 80-125° C, the best system (efficiency up to 14%) consisted of a regular four stage Rankine cycle with iso-butane as the working fluid. If input temperature of 100-150° C can be reached, a closed loop pre-heater design with n-Pentane can produce very effective systems (15-21%). Methanol and ethanol seem best suited for higher temperature applications were the possibility of co-generation could be explored. Residential solar thermal electricity generation is a feasibly technology and as solar collects and micro expanders develop more, it can become a leader in renewable energy.No embarg

Just the Facts: Demographic and Cross-Country Dimensions of the Employment Slump

We present data characterizing the U.S. labor market during the Great Recession and subsequent recovery. U.S. employment declines were dramatic among young adults, substantial among prime-aged adults, and modest among those near retirement. The decline in employment among working-age adults generally exceeded those that occurred in other advanced economies. We assess the potential explanatory power of population aging and increases in educational attainment as factors underlying these developments. Recent analyses suggest that population aging can explain nearly one half of the decline in the labor force participation rate and one third of the decline in the employment to population ratio from 2007 to 2013. Our comparisons of employment developments across age groups and countries provide reason to view this one third as an upper bound on aging's plausible contribution. We conduct a more detailed analysis of changes in employment and school attendance across demographic sub-groups of the young adult population. Across sub-groups defined by age, gender, and race/ethnicity, changes in school enrollment predict very little of the variation in this period's employment changes. Taken together, aging and enrollment trends thus appear to underlie a modest to moderate fraction of the aggregate employment decline. We conclude by discussing a range of non-demographic factors that may have contributed to the decline, but on which existing research has yet to arrive at a consensus

Just the Facts: Demographic and Cross-Country Dimensions of the Employment Slump

We present data characterizing the U.S. labor market during the Great Recession and subsequent recovery. U.S. employment declines were dramatic among young adults, substantial among prime-aged adults, and modest among those near retirement. The decline in employment among working-age adults generally exceeded those that occurred in other advanced economies. We assess the potential explanatory power of population aging and increases in educational attainment as factors underlying these developments. Recent analyses suggest that population aging can explain nearly one half of the decline in the labor force participation rate and one third of the decline in the employment to population ratio from 2007 to 2013. Our comparisons of employment developments across age groups and countries provide reason to view this one third as an upper bound on aging's plausible contribution. We conduct a more detailed analysis of changes in employment and school attendance across demographic sub-groups of the young adult population. Across sub-groups defined by age, gender, and race/ethnicity, changes in school enrollment predict very little of the variation in this period's employment changes. Taken together, aging and enrollment trends thus appear to underlie a modest to moderate fraction of the aggregate employment decline. We conclude by discussing a range of non-demographic factors that may have contributed to the decline, but on which existing research has yet to arrive at a consensus

A discrete cluster of urinary biomarkers discriminates between active systemic lupus erythematosus patients with and without glomerulonephritis.

BackgroundManagement of lupus nephritis (LN) would be greatly aided by the discovery of biomarkers that accurately reflect changes in disease activity. Here, we used a proteomics approach to identify potential urinary biomarkers associated with LN.MethodsUrine was obtained from 60 LN patients with paired renal biopsies, 25 active non-LN SLE patients, and 24 healthy controls. Using Luminex, 128 analytes were quantified and normalized to urinary creatinine levels. Data were analyzed by linear modeling and non-parametric statistics, with corrections for multiple comparisons. A second cohort of 33 active LN, 16 active non-LN, and 30 remission LN SLE patients was used to validate the results.ResultsForty-four analytes were identified that were significantly increased in active LN as compared to active non-LN. This included a number of unique proteins (e.g., TIMP-1, PAI-1, PF4, vWF, and IL-15) as well as known candidate LN biomarkers (e.g., adiponectin, sVCAM-1, and IL-6), that differed markedly (>4-fold) between active LN and non-LN, all of which were confirmed in the validation cohort and normalized in remission LN patients. These proteins demonstrated an enhanced ability to discriminate between active LN and non-LN patients over several previously reported biomarkers. Ten proteins were found to significantly correlate with the activity score on renal biopsy, eight of which strongly discriminated between active proliferative and non-proliferative/chronic renal lesions.ConclusionsA number of promising urinary biomarkers that correlate with the presence of active renal disease and/or renal biopsy changes were identified and appear to outperform many of the existing proposed biomarkers