The structure of gravel-bed flow with intermediate submergence: a laboratory study

The paper reports an experimental study of the flow structure over an immobile gravel bed in open channel at intermediate submergence, with particular focus on the near-bed region. The experiments consisted of velocity measurements using three-component (stereoscopic) Particle Image Velocimetry (PIV) in near-bed horizontal plane and two-component PIV in three vertical planes that covered three distinctly different hydraulic scenarios where the ratio of flow depth to roughness height (i.e., relative submergence) changes from 7.5 to 10.8. Detailed velocity measurements were supplemented with fine-scale bed elevation data obtained with a laser scanner. The data revealed longitudinal low-momentum and high-momentum "strips'' in the time-averaged velocity field, likely induced by secondary currents. This depth-scale pattern was superimposed with particle-scale patches of flow heterogeneity induced by gravel particle protrusions. A similar picture emerged when considering second-order velocity moments. The interaction between the flow field and gravel-bed protrusions is assessed using cross correlations of velocity components and bed elevations in a horizontal plane just above gravel particle crests. The cross correlations suggest that upward and downward fluid motions are mainly associated with upstream-facing and lee sides of particles, respectively. Results also show that the relative submergence affects the turbulence intensity profiles for vertical velocity over the whole flow depth, while only a weak effect, limited to the near-bed region, is noticed for streamwise velocity component. The approximation of mean velocity profiles with a logarithmic formula reveals that log-profile parameters depend on relative submergence, highlighting inapplicability of a conventional "universal'' logarithmic law for gravel-bed flows with intermediate submergence

The distribution and hydrological significance of rock glaciers in the Nepalese Himalaya

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.In the Nepalese Himalaya, there is little information on the number, spatial distribution and morphometric characteristics of rock glaciers, and this information is required if their hydrological contribution is to be understood. Based on freely available fine spatial resolution satellite data accessible through Google Earth, we produced the first comprehensive Nepalese rock glacier inventory, supported through statistical validation and field survey. The inventory includes the location of over 6000 rock glaciers, with a mean specific density of 3.4%. This corresponds to an areal coverage of 1371 km². Our approach subsampled approximately 20% of the total identified rock glacier inventory (n = 1137) and digitised their outlines so that quantitative/qualitative landform attributes could be extracted. Intact landforms (containing ice) accounted for 68% of the subsample, and the remaining were classified as relict (not containing ice). The majority (56%) were found to have a northerly aspect (NE, N, and NW), and landforms situated within north- to west-aspects reside at lower elevations than those with south- to- east aspects. In Nepal, we show that rock glaciers are situated between 3225 to 5675 m a.s.l., with the mean minimum elevation at the front estimated to be 4977±280 m a.s.l. for intact landforms and 4541±346 m a.s.l. for relict landforms. The hydrological significance of rock glaciers in Nepal was then established by statistically upscaling the results from the subsample to estimate that these cryospheric reserves store between 16.72 and 25.08 billion cubic metres of water. This study, for the first time, estimates rock glacier water volume equivalents and evaluates their relative hydrological importance in comparison to ice glaciers. Across the Nepalese Himalaya, rock glacier to ice glacier water volume equivalent is 1:9, and generally increases westwards (e.g., ratio = 1:3, West region). This inventory represents a preliminary step for understanding the spatial distribution and the geomorphic conditions necessary for rock glacier formation in the Himalaya. With continued climatically-driven ice glacier recession, the relative importance of rock glaciers in the Nepalese Himalaya will potentially increase.This work was supported by the Natural Environment Research Council (grant number: 851 NE/L002434/1 to DBJ); the Royal Geographical Society (with IBG) with a Dudley Stamp Memorial Award 852 (awarded to DBJ); the European Union Seventh Framework Programme FP7/2007-2013 (grant number: 603864 853 to SH and RAB [HELIX: High-End cLimate Impacts and eXtremes; www.helixclimate.eu]). The work of RB forms 854 part of the BEIS/Defra Met Office Hadley Centre Climate Programme GA01101.

Pest and disease management system for supporting winter oilseed rape decisions (PASSWORD) - vaildation phase (HGCA Project Report No. 390)

Pests and particularly diseases cause serious loss of yield and quality in winter oilseed rape estimated to exceed £80 million/annum in some years. These losses have occurred despite an annual expenditure of about £3.5 million for insecticides and £12 million on fungicides. Decision-making is difficult because there is complex spatial and temporal variation in pest and disease problems and improved guidance is required. The main objective of this project was to test new disease models developed in the first phase of this project and deliver a decision support system for both pest and disease control in oilseed rape. The regional light leaf spot forecast is well-established and reliable and indicates an increased risk of this disease in spring 2006. A new regional forecast for stem canker incidence preharvest has been developed and made available on the Internet. It was successful in 2004/05 and offers strategic guidance on risk provided weather factors are within the range used to develop the model. A four-stage crop-specific stem canker risk assessment method was developed that predicts the onset of phoma leaf spotting using post-harvest weather data and thermal time relationships for canker development and canker severity. Yield loss can then be calculated from canker severity and the economic impact of stem canker predicted. There is some flexibility in the timing of fungicide sprays to control stem canker. Delays of 2 to 3 weeks beyond a 10-20% plants affected threshold did not adversely affect yield. Stem canker severity and yield of different cultivars showed large variation between years and sites and smaller, but significant, variation in responses to fungicide. When phoma leaf spot appears in late autumn, it is only when plants are small that stem canker is likely to cause yield loss. In commercial crops, there were consistent trends for higher yields to be associated with higher fungicide inputs. Light leaf spot was very difficult to control with fungicides in the Aberdeen area where use of resistant cultivars is essential. The most effective disease control was obtained using a combination of resistant cultivars and fungicides. In some years, responses to fungicides were not cost-effective and targeting their use to high-risk situations is necessary to give the best margins over input costs. Close contact was maintained with potential users during the project and they influenced priorities and design features. The components of PASSWORD decision support system were tested and provide guidance for the management of invertebrate pests, phoma stem canker and light leaf spot. The system will be available to ArableDS for use in autumn 2006

Serum methylarginines and spirometry-measured lung function in older adults

Rationale: Methylarginines are endogenous nitric oxide synthase inhibitors that have been implicated in animal models of lung disease but have not previously been examined for their association with spirometric measures of lung function in humans. Objectives: This study measured serum concentrations of asymmetric and symmetric dimethylarginine in a representative sample of older community-dwelling adults and determined their association with spirometric lung function measures. Methods: Data on clinical, lifestyle, and demographic characteristics, methylated arginines, and L-arginine (measured using LC-MS/MS) were collected from a population-based sample of older Australian adults from the Hunter Community Study. The five key lung function measures included as outcomes were Forced Expiratory Volume in 1 second, Forced Vital Capacity, Forced Expiratory Volume in 1 second to Forced Vital Capacity ratio, Percent Predicted Forced Expiratory Volume in 1 second, and Percent Predicted Forced Vital Capacity. Measurements and Main Results: In adjusted analyses there were statistically significant independent associations between a) higher asymmetric dimethylarginine, lower Forced Expiratory Volume in 1 second and lower Forced Vital Capacity; and b) lower L-arginine/asymmetric dimethylarginine ratio, lower Forced Expiratory Volume in 1 second, lower Percent Predicted Forced Expiratory Volume in 1 second and lower Percent Predicted Forced Vital Capacity. By contrast, no significant associations were observed between symmetric dimethylarginine and lung function. Conclusions: After adjusting for clinical, demographic, biochemical, and pharmacological confounders, higher serum asymmetric dimethylarginine was independently associated with a reduction in key measures of lung function. Further research is needed to determine if methylarginines predict the decline in lung function

Defining the phospho-adhesome through the phosphoproteomic analysis of integrin signalling

Cell-extracellular matrix (ECM) adhesion is a fundamental requirement for multicellular existence due to roles in positioning, proliferation and differentiation. Phosphorylation plays a major role in adhesion signalling; however, a full understanding of the phosphorylation events that occur at sites of adhesion is lacking. Here we report a proteomic and phosphoproteomic analysis of adhesion complexes isolated from cells spread on fibronectin. We identify 1,174 proteins, 499 of which are phosphorylated (1,109 phosphorylation sites), including both well-characterized and novel adhesion-regulated phosphorylation events. Immunoblotting suggests that two classes of phosphorylated residues are found at adhesion sites-those induced by adhesion and those constitutively phosphorylated but recruited in response to adhesion. Kinase prediction analysis identifies novel kinases with putative roles in adhesion signalling including CDK1, inhibition of which reduces adhesion complex formation. This phospho-adhesome data set constitutes a valuable resource to improve our understanding of the signalling mechanisms through which cell-ECM interactions control cell behaviour