The trophic importance of epiphytic algae in a freshwater macrophyte system (Potamogeton perfoliatus L.): stable isotope and fatty acid analyses

Stable isotope and fatty acid analyses were used to study carbon sources for animals in a submerged plant bed. Epiphytes growing on Potamogeton perfoliatus, sand microflora, and alder leaves were the most important carbon sources. The most abundant macrophyte, P. perfoliatus was unimportant as a food source. Modelling (IsoSource) showed that epiphytes were the most important food source for the most abundant benthic invertebrates, the isopod Asellus aquaticus (annual mean contribution 64%), the amphipod Gammarus pulex (66%), and the gastropod Potamopyrgus antipodarum (83%). The mean annual contributions of sand microflora were, respectively, 21, 19, and 9%; and of alder leaves, 15, 15, and 8% for these three species. The relative importance of carbon sources varied seasonally. The relative contribution of epiphytes was lowest for all three grazer species in July: A. aquaticus 38%, G. pulex 43%, and P. antipodarum 42%. A decline in epiphyte biomass in summer may have caused this switch to less attractive food sources. P. perfoliatus provided habitat and shelter for consumers, but food was mainly supplied indirectly by providing space for attached epiphytes, which are fast-growing and provide a highly nutritious food source

Genomic Organization of H2Av Containing Nucleosomes in Drosophila Heterochromatin

H2Av is a versatile histone variant that plays both positive and negative roles in transcription, DNA repair, and chromatin structure in Drosophila. H2Av, and its broader homolog H2A.Z, tend to be enriched toward 5′ ends of genes, and exist in both euchromatin and heterochromatin. Its organization around euchromatin genes and other features have been described in many eukaryotic model organisms. However, less is known about H2Av nucleosome organization in heterochromatin. Here we report the properties and organization of individual H2Av nucleosomes around genes and transposable elements located in Drosophila heterochromatic regions. We compare the similarity and differences with that found in euchromatic regions. Our analyses suggest that nucleosomes are intrinsically positioned on inverted repeats of DNA transposable elements such as those related to the “1360” element, but are not intrinsically positioned on retrotransposon-related elements

Evaluating WRF-Chem multi-scale model in simulating aerosol radiative properties over the tropics - A case study over India

We evaluated the performance of WRF-Chem multi-scale model over the tropics, to simulate the regional distribution and optical properties of aerosols, and its effect on radiation over India for a winter month. The model is evaluated using measurements obtained from upper-air soundings, AERONET sun photometers, various satellite instruments, and pyranometers. The simulated downward shortwave flux was overestimated when the effect of aerosols and clouds, on radiation, was -2 neglected. The simulated downward shortwave radiation was 1 to 20 Wm closer to the observations when we included aerosol-cloud-radiation interaction in the simulation. The model usually underestimated particulate concentration for the few observations available. This is likely due to turbulent mixing, transport errors and the lack of dust emission/scheme and the secondary organic aerosol treatment in the model. The model efficiently captured the broad regional hotspots such as, higher aerosol optical depth over the northern parts of India, especially over the Indo-Gangetic basin and lower aerosol optical depth over southern parts of India. The regional distribution of aerosol optical depth agreed well with the AVHRR aerosol optical depth and the TOMS aerosol index pattern. The magnitude and wavelength-dependence of simulated aerosol optical depth was also similar to the AERONET observations across India. The difference in surface shortwave radiation between two simulations that included and neglected aerosol-radiation (aerosol-radiation-cloud) interactions -2 were as high as -25 (-30) Wm -2. The spatial variations of these differences were also compared with the AVHRR observation. This study suggests that the model is able to qualitatively simulate the distribution of particulates and its impact on radiation over India; however, additional measurements of particulate mass and composition are needed to fully evaluate the model performance

Mortality and incidence of second cancers following treatment for testicular cancer

We studied 5555 seminoma patients and 3733 patients with nonseminomatous testicular cancers diagnosed in Southeast England between 1960 and 2004. For both groups survival improved over time: 10-year relative survival increased from 78% in 1960 - 1969 to 99% in 1990 - 2004 for seminomas, and from 55 to 95% for nonseminomas. In the early period mortality was still significantly increased more than 15 years after diagnosis in both groups, whereas in more recent periods the excess deaths mainly occurred in the first 5 years after diagnosis. For seminomas, there was a significant excess of cancers of the colon ( standardised incidence ratio ( SIR) 2.36; 95% confidence interval (CI) 1.13 - 4.35), soft tissue ( SIR 13.64; CI 1.65 - 49.28) and bladder ( SIR 4.28; CI 2.28 - 7.31) in the long term (20 + years after diagnosis), of pancreatic cancer in both the medium ( 10 - 19 years) ( SIR 2.91; CI 1.26 - 5.73) and long term ( SIR 5.48; CI 2.37 - 10.80), of leukaemia in both the short ( 0 - 9 years) ( SIR 3.01; CI 1.44 - 5.54) and long term ( SIR 4.48; CI 1.64 - 9.75), and of testis cancer in both the short ( SIR 6.69; CI 4.28 - 9.95) and medium term ( SIR 3.96; CI 1.08 - 10.14). For nonseminomas, significant excesses were found in the long term for cancers of the stomach ( SIR 5.13; CI 1.40 - 13.13), rectum ( SIR 4.49; CI 1.22 - 11.51) and pancreas ( SIR 10.17: CI 3.73 - 22.13), and for testis cancer in the medium term ( SIR 5.94; CI 2.18 - 12.93). Leukaemia was significantly increased in the short term ( SIR 6.78; CI 2.93 - 13.36). The better survival observed is largely attributable to improved treatment, and the trend in reducing the toxicity of therapy should continue to reduce future health risks in testicular cancer survivor