Spatial pattern and process at the plant neighbourhood scale: insights from communities dominated by the clonal grass Elymus repens (L.) Gould.

Question: How do clonal traits of a locally dominant grass (Elymus repens (L.) Gould.) respond to soil heterogeneity and shape spatial patterns of its tillers? How do tiller spatial patterns constrain seedling recruitment within the community?Locations: Artificial banks of the River Rhone, France.Material and Methods: We examined 45 vegetation patches dominated by Elymus repens. During a first phase we tested relationships between soil variables and three clonal traits (spacer length, number of clumping tillers and branching rate), and between the same clonal traits and spatial patterns (i.e. density and degree of spatial aggregation) of tillers at a very fine scale. During a second phase, we performed a sowing experiment to investigate effects of density and spatial patterns of E. repens on recruitment of eight species selected from the regional species pool.Results: Clonal traits had clear effects - especially spacer length - on densification and aggregation of E. repens tillers and, at the same time, a clear response of these same clonal traits as soil granulometry changed. The density and degree of aggregation of E. repens tillers was positively correlated to total seedling cover and diversity at the finest spatial scales.Conclusions: Spatial patterning of a dominant perennial grass responds to soil heterogeneity through modifications of its clonal morphology as a trade-off between phalanx and guerrilla forms. In turn, spatial patterns have strong effects on abundance and diversity of seedlings. Spatial patterns of tillers most probably led to formation of endogenous gaps in which the recruitment of new plant individuals was enhanced. Interestingly, we also observed more idiosyncratic effects of tiller spatial patterns on seedling cover and diversity when focusing on different growth forms of the sown species.

SDF 1-alpha (CXCL12) triggers glutamate exocytosis from astrocytes on a millisecond time scale: Imaging analysis at the single-vesicle level with TIRF microscopy

Chemokines are small chemotactic molecules widely expressed throughout the central nervous system. A number of papers, during the past few years, have suggested that they have physiological functions in addition to their roles in neuroinflammatory diseases. In this context, the best evidence concerns the CXC-chemokine stromal cell-derived factor (SDF-1alpha or CXCL12) and its receptor CXCR4, whose signalling cascade is also implicated in the glutamate release process from astrocytes. Recently, astrocytic synaptic like microvesicles (SLMVs) that express vesicular glutamate transporters (VGLUTs) and are able to release glutamate by Ca(2+)-dependent regulated exocytosis, have been described both in tissue and in cultured astrocytes. Here, in order to elucidate whether SDF-1alpha/CXCR4 system can participate to the brain fast communication systems, we investigated whether the activation of CXCR4 receptor triggers glutamate exocytosis in astrocytes. By using total internal reflection (TIRF) microscopy and the membrane-fluorescent styryl dye FM4-64, we adapted an imaging methodology recently developed to measure exocytosis and recycling in synaptic terminals, and monitored the CXCR4-mediated exocytosis of SLMVs in astrocytes. We analyzed the co-localization of VGLUT with the FM dye at single-vesicle level, and observed the kinetics of the FM dye release during single fusion events. We found that the activation of CXCR4 receptors triggered a burst of exocytosis on a millisecond time scale that involved the release of Ca(2+) from internal stores. These results support the idea that astrocytes can respond to external stimuli and communicate with the neighboring cells via fast release of glutamate.

Construction of a scale to evaluate the diurnal impact of insomnia

The objective of this study was to develop and validate a scale to assess the diurnal impact of insomnia. The Insomnia Diurnal Impact Scale (IDIS) comprises six items designed to evaluate the daytime effects of insomnia. The sychometric properties of the original scale were analysed in a sample of 172 students, while its ability to differentiate insomniacs and non-insomniacs (according to the International Classification of Diseases (ICD)-10 criteria) was examined in a sample of 79 psychiatric patients and 82 individuals from the community. The psychometric properties of the English version were then analysed in a sample of 44 Englishspeaking participants. The results showed the internal consistency coefficient to be very good (0.86), with testretest reliability at 1 month being 0.79. A single factor explained almost 60% of the variance. Correlation of the IDIS with other scales varied between moderate and high values. Sensitivity was 78% and specificity 57% in the community sample, while the corresponding figures for the psychiatric population were 83% and 63%. Cronbach's ¿ coefficient for the English version reached a value of 0.93. These results indicate that the IDIS shows adequate reliability and validity with both general and psychiatric populations, and also that it can discriminate between the presence and absence of insomnia. The English version presents good preliminary results regarding item-corrected total correlation and internal consistency. In conclusion, the IDIS appears to be a useful tool in the primary care and mental health contexts for assessing insomnia-related diurnal dysfunction.

Modelling hydrodynamics in the Rio Parana, Argentina : an evaluation and inter-comparison of reduced-complexity and physics based models applied to a large sand-bed river

Depth-averaged velocities and unit discharges within a 30 km reach of one of the world's largest rivers, the Rio Parana, Argentina, were simulated using three hydrodynamic models with different process representations: a reduced complexity (RC) model that neglects most of the physics governing fluid flow, a two-dimensional model based on the shallow water equations, and a three-dimensional model based on the Reynolds-averaged Navier-Stokes equations. Row characteristics simulated using all three models were compared with data obtained by acoustic Doppler current profiler surveys at four cross sections within the study reach. This analysis demonstrates that, surprisingly, the performance of the RC model is generally equal to, and in some instances better than, that of the physics based models in terms of the statistical agreement between simulated and measured flow properties. In addition, in contrast to previous applications of RC models, the present study demonstrates that the RC model can successfully predict measured flow velocities. The strong performance of the RC model reflects, in part, the simplicity of the depth-averaged mean flow patterns within the study reach and the dominant role of channel-scale topographic features in controlling the flow dynamics. Moreover, the very low water surface slopes that typify large sand-bed rivers enable flow depths to be estimated reliably in the RC model using a simple fixed-lid planar water surface approximation. This approach overcomes a major problem encountered in the application of RC models in environments characterised by shallow flows and steep bed gradients. The RC model is four orders of magnitude faster than the physics based models when performing steady-state hydrodynamic calculations. However, the iterative nature of the RC model calculations implies a reduction in computational efficiency relative to some other RC models. A further implication of this is that, if used to simulate channel morphodynamics, the present RC model may offer only a marginal advantage in terms of computational efficiency over approaches based on the shallow water equations. These observations illustrate the trade off between model realism and efficiency that is a key consideration in RC modelling. Moreover, this outcome highlights a need to rethink the use of RC morphodynamic models in fluvial geomorphology and to move away from existing grid-based approaches, such as the popular cellular automata (CA) models, that remain essentially reductionist in nature. In the case of the world's largest sand-bed rivers, this might be achieved by implementing the RC model outlined here as one element within a hierarchical modelling framework that would enable computationally efficient simulation of the morphodynamics of large rivers over millennial time scales. (C) 2012 Elsevier B.V. All rights reserved.

The co-evolution of social institutions, demography, and large-scale human cooperation.

Human cooperation is typically coordinated by institutions, which determine the outcome structure of the social interactions individuals engage in. Explaining the Neolithic transition from small- to large-scale societies involves understanding how these institutions co-evolve with demography. We study this using a demographically explicit model of institution formation in a patch-structured population. Each patch supports both social and asocial niches. Social individuals create an institution, at a cost to themselves, by negotiating how much of the costly public good provided by cooperators is invested into sanctioning defectors. The remainder of their public good is invested in technology that increases carrying capacity, such as irrigation systems. We show that social individuals can invade a population of asocials, and form institutions that support high levels of cooperation. We then demonstrate conditions where the co-evolution of cooperation, institutions, and demographic carrying capacity creates a transition from small- to large-scale social groups.

Modelling of vegetative filter strips in catchment scale erosin control

Selostus: Valuma-aluetason mallisovellus suojakaistojen käytöstä eroosion torjunnassa

Feasibility Study of Dynamic Overload and Ultimate Load Tests of Full-Scale Highway Bridges, HR-160, 1973

As a result of the construction of the Saylorville Dam and Reservoir on the Des Moines River, six highway bridges are scheduled for removal. Five of these are old high-truss single-lane bridges, each bridge having several simple spans. The other bridge is a fairly modern (1955) double 4-span continuous beam-and-slab composite highway bridge. The availability of these bridges affords an unusual opportunity for study of the behavior of full-scale bridges. Because of the magnitude of the potential testing program, a feasibility study was initiated and the results are presented in this two-part final report. Part I summarizes the findings and Part II presents the supporting detailed information.

Ultimate Load Behavior of Full-Scale Highway Truss Bridges, Summary Report, HR-169, 1975

As a result of the construction of the Saylorville Dam and Reservoir on the Des Moines River, six highway bridges crossing the river were scheduled for removal. One of these, an old pin-connected, high-truss, single-lane bridge, was selected for a comprehensive testing program which included ultimate load tests, service load tests, and a supplementary test program. A second bridge was used for a limited service load test program. The results of the research are detailed in two interim reports. The first interim report outlines the ultimate load tests and the second interim report details the results of the service load and supplementary test program. This report presents a summary of these findings along with recommendations for implementation of the findings.

Large-scale clustering through functional embedding

We present a new framework for large-scale data clustering. The main idea is to modify functional dimensionality reduction techniques to directly optimize over discrete labels using stochastic gradient descent. Compared to methods like spectral clustering our approach solves a single optimization problem, rather than an ad-hoc two-stage optimization approach, does not require a matrix inversion, can easily encode prior knowledge in the set of implementable functions, and does not have an ?out-of-sample? problem. Experimental results on both artificial and real-world datasets show the usefulness of our approach.

Exploring the proposed DSM-5 diagnostic threshold and severity scale for the alcohol use disorder

Aims :¦Several studies have questioned the validity of separating the diagnosis of alcohol abuse from that of alcohol dependence, and the DSM-5 task force has proposed combining the criteria from these two diagnoses to assess a single category of alcohol use disorders (AUD). Furthermore, the DSM-5 task force has proposed including a new 2-symptom threshold and a severity scale based on symptom counts for the AUD diagnosis. The current study aimed to examine these modifications in a large population-based sample.¦Method :¦Data stemmed from an adult sample (N=2588 ; mean age 51.3 years (s.d.: 0.2), 44.9% female) of current and lifetime drinkers from the PsyCoLaus study, conducted in the Lausanne area in Switzerland. AUDs and validating variables were assessed using a semi-structured diagnostic interview for the assessment of alcohol¦and other major psychiatric disorders. First, the adequacy of the proposed 2- symptom threshold was tested by comparing threshold models at each possible cutoff and a linear model, in relation to different validating variables. The model with the smallest Akaike Criterion Information (AIC) value was established as the best¦model for each validating variable. Second, models with varying subsets of individual AUD symptoms were created to assess the associations between each symptom and the validating variables. The subset of symptoms with the smallest AIC value was established as the best subset for each validator.¦Results :¦1) For the majority of validating variables, the linear model was found to be the best fitting model. 2) Among the various subsets of symptoms, the symptoms most frequently associated with the validating variables were : a) drinking despite having knowledge of a physical or psychological problem, b) having had a persistent desire or unsuccessful efforts to cut down or control drinking and c) craving. The¦least frequent symptoms were : d) drinking in larger amounts or over a longer period than was intended, e) spending a great deal of time in obtaining, using or recovering from alcohol use and f) failing to fulfill major role obligations.¦Conclusions :¦The proposed DSM-5 2-symptom threshold did not receive support in our data. Instead, a linear AUD diagnosis was supported with individuals receiving an increasingly severe AUD diagnosis. Moreover, certain symptoms were more frequently associated with the validating variables, which suggests that these¦symptoms should be considered as more severe.

Bioinformatics: making large-scale science happen

Bionformatics is a rapidly evolving research field dedicated toanalyzing and managing biological data with computational resources. This paperaims to overview some of the processes and applications currently implementedat CCiT-UB¿s Bioinformatics Unit, focusing mainly on the areas of Genomics,Transcriptomics and Proteomics

Inclusion of soil erosion impacts in life cycle assessment on a global scale: application to energy crops in Spain

Purpose: Despite the fundamental role of ecosystem goods and services in sustaining human activities, there is no harmonized and internationally agreed method for including them in life cycle assessment (LCA). The main goal of this study was to develop a globally applicable and spatially resolved method for assessing land-use impacts on the erosion regulation ecosystem service.Methods: Soil erosion depends much on location. Thus, unlike conventional LCA, the endpoint method was regionalized at the grid-cell level (5 arc-minutes, approximately 10×10 km2) to reflect the spatial conditions of the site. Spatially explicit characterization factors were not further aggregated at broader spatial scales. Results and discussion: Life cycle inventory data of topsoil and topsoil organic carbon (SOC) losses were interpreted at the endpoint level in terms of the ultimate damage to soil resources and ecosystem quality. Human health damages were excluded from the assessment. The method was tested on a case study of five three-year agricultural rotations, two of them with energy crops, grown in several locations in Spain. A large variation in soil and SOC losses was recorded in the inventory step, depending on climatic and edaphic conditions. The importance of using a spatially explicit model and characterization factors is shown in the case study.Conclusions and outlook: The regionalized assessment takes into account the differences in soil erosion-related environmental impacts caused by the great variability of soils. Taking this regionalized framework as the starting point, further research should focus on testing the applicability of the method trough the complete life cycle of a product and on determining an appropriate spatial scale at which to aggregate characterization factors, in order to deal with data gaps on location of processes, especially in the background system. Additional research should also focus on improving reliability of the method by quantifying and, insofar as it is possible, reducing uncertainty.

A Spanish version of the short Mathematics Anxiety Rating Scale (sMARS)

The aim of this studywas to adapt and assess the psychometric properties of the Spanish version of the sMARS in terms of evidence of validity and reliability of scores. The sMARS was administered to 342 students and, in order to assess convergent and discriminant validity, several subsamples completed a series of related tests. The factorial structure of the sMARSwas analyzed by means of a confirmatory factor analysis and results showed that the three-factor structure reported in the original test fits well with the data. Thus, three dimensions were established in the test: math test, numerical task and math course anxiety. The results of this study provide sound evidence that demonstrates the good psychometric properties of the scores of the Spanish version of the sMARS: strong internal consistency, high 7-week testretest reliability and good convergent/discriminant validity were evident. Overall, this study provides an instrument that allows us to obtain valid and reliable math anxiety measurements. This instrument may be a useful tool for educators and psychologists interested in identifying individuals that may have a low level of math mastery because of their anxiety.