Changing climate both increases and decreases European river floods

Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere1. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe2. Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning. However, existing studies have been unable to identify a consistent continental-scale climatic-change signal in flood discharge observations in Europe3, because of the limited spatial coverage and number of hydrometric stations. Here we demonstrate clear regional patterns of both increases and decreases in observed river flood discharges in the past five decades in Europe, which are manifestations of a changing climate. Our results\u2014arising from the most complete database of European flooding so far\u2014suggest that: increasing autumn and winter rainfall has resulted in increasing floods in northwestern Europe; decreasing precipitation and increasing evaporation have led to decreasing floods in medium and large catchments in southern Europe; and decreasing snow cover and snowmelt, resulting from warmer temperatures, have led to decreasing floods in eastern Europe. Regional flood discharge trends in Europe range from an increase of about 11 per cent per decade to a decrease of 23 per cent. Notwithstanding the spatial and temporal heterogeneity of the observational record, the flood changes identified here are broadly consistent with climate model projections for the next century4,5, suggesting that climate-driven changes are already happening and supporting calls for the consideration of climate change in flood risk management

Association of Immunosuppression and Human Immunodeficiency Virus (HIV) Viremia with Anal Cancer Risk in Persons Living with HIV in the United States and Canada

Background: People living with human immunodeficiency virus (HIV; PLWH) have a markedly elevated anal cancer risk, largely due to loss of immunoregulatory control of oncogenic human papillomavirus infection. To better understand anal cancer development and prevention, we determined whether recent, past, cumulative, or nadir/peak CD4+ T-cell count (CD4) and/or HIV-1 RNA level (HIV RNA) best predict anal cancer risk. Methods: We studied 102 777 PLWH during 1996-2014 from 21 cohorts participating in the North American AIDS Cohort Collaboration on Research and Design. Using demographics-adjusted, cohort-stratified Cox models, we assessed associations between anal cancer risk and various time-updated CD4 and HIV RNA measures, including cumulative and nadir/peak measures during prespecified moving time windows. We compared models using the Akaike information criterion. Results: Cumulative and nadir/peak CD4 or HIV RNA measures from approximately 8.5 to 4.5 years in the past were generally better predictors for anal cancer risk than their corresponding more recent measures. However, the best model included CD4 nadir (ie, the lowest CD4) from approximately 8.5 years to 6 months in the past (hazard ratio [HR] for <50 vs ≥500 cells/μL, 13.4; 95% confidence interval [CI], 3.5-51.0) and proportion of time CD4 <200 cells/μL from approximately 8.5 to 4.5 years in the past (a cumulative measure; HR for 100% vs 0%, 3.1; 95% CI, 1.5-6.6). Conclusions: Our results are consistent with anal cancer promotion by severe, prolonged HIV-induced immunosuppression. Nadir and cumulative CD4 may represent useful markers for identifying PLWH at higher anal cancer risk

An investigation of balsa wood over a range of strain-rates and impact velocities

An experimental investigation of the mechanical properties of balsa wood under quasi-static and dynamic conditions is presented. Cylindrical balsa wood specimens were compressed quasi-statically and dynamically along their three principal axes. Split Hopkinson Pressure Bar (SHPB) tests were carried out to determine the importance of the material strain-rate. Balsa wood is a relatively low strength material of about 1.5 MPa in the weakest direction, depending on density. Consequently, the SHPB tests were carried out using low mechanical impedance Polymethylmethacrylate pressure bars. Tests at high strain-rates resulted in an increase in both initial crushing and plateau stresses. Direct impact (DI) tests were performed to measure both the proximal and distal end forces over a range of impact velocities. These results both reinforce the SHPB data and provide measurements for stress enhancement

Techies and Firm Level Productivity

We study the impact of techies—engineers and other technically trained workers—on firm-level productivity. We first report new facts on the role of techies in the firm by using French administrative data and unique surveys. Techies are STEM-skill intensive and are associated with innovation, as well as with technology adoption, management, and diffusion within firms. Using structural econometric methods, we estimate the causal effect of techies on firm-level Hicks-neutral productivity in both manufacturing and non-manufacturing industries. We find that techies raise firm-level productivity, and this effect goes beyond the employment of R&D workers, extending to ICT and other techies. In non-manufacturing firms, the impact of techies on productivity operates mostly through ICT and other techies, not R&D workers. Engineers have a greater effect on productivity than technicians

Three-dimensional in situ observations of compressive damage mechanisms in syntactic foam using X-ray microcomputed tomography

Syntactic foams with hollow glass microspheres embedded in an epoxy matrix are used in marine, aerospace and ground transportation vehicle applications. This work presents an in situ experimental study of failure mechanisms in syntactic foam based on X-ray microcomputed tomography with uniaxial compression. Under different levels of compressive strain, the material was scanned using X-ray microcomputed tomography to obtain three-dimensional (3D) images of its internal microstructure. Experiments with the same parameters were carried out to investigate repeatability. The microscopic observations have suggested that damage nucleation occurs at the weakest microspheres. When applied strain increases, shear collapse bands (SCBs) develop local to the fragmented microspheres due to stress concentration and bending deformation around SCBs occurs. After significant strain, the thickness of the SCBs increases owing to the accumulation of the broken microspheres. The relationship between the volume fraction of microspheres and applied bulk strain has been characterised

Quality changes of hot smoked catfish (clarias gariepinus) during refrigerated storage

Changes in the quality of hot smoked catfish were determined just after smoking and during refrigerated storage. Chemical, sensory and microbiological analyses of the samples were carried out during the storage to test their shelf life and quality. Total viable count, total volatile basic nitrogen, peroxide values and thiobarbituric acid values increased, while sensory scores decreased during storage. The pH values were slightly increased by storage time. It was found that hot smoked catfish samples were unfit for human consumption at day 24 according to microbiological and sensory analyses. Results of this study can be applied to improve the existing methods of catfish processing. The findings exemplify the storage ability of hot smoked catfish for a period of as long as 24 days under refrigerated storage. These findings can be well utilized by researchers as well as manufacturers in the economic preparation of hot smoked fish products and for long-term storage. Based on these results, suitable methods of preservation and packaging techniques can be developed for improving the shelf life of hot smoked catfish. © 2007, Blackwell Publishing