A Monte Carlo approach to the inverse problem of diffuse pollution risk in agricultural catchments

The hydrological and biogeochemical processes that operate in catchments influence the ecological quality of freshwater systems through delivery of fine sediment, nutrients and organic matter. Most models that seek to characterise the delivery of diffuse pollutants from land to water are reductionist. The multitude of processes that are parameterised in such models to ensure generic applicability make them complex and difficult to test on available data. Here, we outline an alternative - data-driven - inverse approach. We apply SCIMAP, a parsimonious risk based model that has an explicit treatment of hydrological connectivity. we take a Bayesian approach to the inverse problem of determining the risk that must be assigned to different land uses in a catchment in order to explain the spatial patterns of measured in-stream nutrient concentrations. We apply the model to identify the key sources of nitrogen (N) and phosphorus (P) diffuse pollution risk in eleven UK catchments covering a range of landscapes. The model results show that: 1) some land use generates a consistently high or low risk of diffuse nutrient pollution; but 2) the risks associated with different land uses vary both between catchments and between nutrients; and 3) that the dominant sources of P and N risk in the catchment are often a function of the spatial configuration of land uses. Taken on a case-by-case basis, this type of inverse approach may be used to help prioritise the focus of interventions to reduce diffuse pollution risk for freshwater ecosystems. (C) 2012 Elsevier B.V. All rights reserved.

A musculoskeletal shoulder model based on pseudo-inverse and null-space optimization.

The goal of the present work was assess the feasibility of using a pseudo-inverse and null-space optimization approach in the modeling of the shoulder biomechanics. The method was applied to a simplified musculoskeletal shoulder model. The mechanical system consisted in the arm, and the external forces were the arm weight, 6 scapulo-humeral muscles and the reaction at the glenohumeral joint, which was considered as a spherical joint. The muscle wrapping was considered around the humeral head assumed spherical. The dynamical equations were solved in a Lagrangian approach. The mathematical redundancy of the mechanical system was solved in two steps: a pseudo-inverse optimization to minimize the square of the muscle stress and a null-space optimization to restrict the muscle force to physiological limits. Several movements were simulated. The mathematical and numerical aspects of the constrained redundancy problem were efficiently solved by the proposed method. The prediction of muscle moment arms was consistent with cadaveric measurements and the joint reaction force was consistent with in vivo measurements. This preliminary work demonstrated that the developed algorithm has a great potential for more complex musculoskeletal modeling of the shoulder joint. In particular it could be further applied to a non-spherical joint model, allowing for the natural translation of the humeral head in the glenoid fossa.

Segmentation and Clustering of Textual Sequences: a Typological Approach

The long term goal of this research is to develop a program able to produce an automatic segmentation and categorization of textual sequences into discourse types. In this preliminary contribution, we present the construction of an algorithm which takes a segmented text as input and attempts to produce a categorization of sequences, such as narrative, argumentative, descriptive and so on. Also, this work aims at investigating a possible convergence between the typological approach developed in particular in the field of text and discourse analysis in French by Adam (2008) and Bronckart (1997) and unsupervised statistical learning.

A gene knockout approach in mice to identify glucose sensors controlling glucose homeostasis.

A key aspect of glucose homeostasis is the constant monitoring of blood glucose concentrations by specific glucose sensing units. These sensors, via stimulation of hormone secretion and activation of the autonomic nervous system (ANS), regulate tissue glucose uptake, utilization or production. The best described glucose detection system is that of the pancreatic beta-cells which controls insulin secretion. Secretion of other hormones, in particular glucagon, and activation of the ANS, are regulated by glucose through sensing mechanisms which are much less well characterized. Here I review some of the studies we have performed over the recent years on a mouse model of impaired glucose sensing generated by inactivation of the gene for the glucose transporter GLUT2. This transporter catalyzes glucose uptake by pancreatic beta-cells, the first step in the signaling cascade leading to glucose-stimulated insulin secretion. Inactivation of its gene leads to a loss of glucose sensing and impaired insulin secretion. Transgenic reexpression of the transporter in GLUT2/beta-cells restores their normal secretory function and rescues the mice from early death. As GLUT2 is also expressed in other tissues, these mice were then studied for the presence of other physiological defects due to absence of this transporter. These studies led to the identification of extra-pancreatic, GLUT2-dependent, glucose sensors controlling glucagon secretion and glucose utilization by peripheral tissues, in part through a control of the autonomic nervous system.

Genetic diversity and differentiation processes in the ploidy series of Olea europaea L.: a multiscale approach from subspecies to insular populations.

Geographical isolation and polyploidization are central concepts in plant evolution. The hierarchical organization of archipelagos in this study provides a framework for testing the evolutionary consequences for polyploid taxa and populations occurring in isolation. Using amplified fragment length polymorphism and simple sequence repeat markers, we determined the genetic diversity and differentiation patterns at three levels of geographical isolation in Olea europaea: mainland-archipelagos, islands within an archipelago, and populations within an island. At the subspecies scale, the hexaploid ssp. maroccana (southwest Morocco) exhibited higher genetic diversity than the insular counterparts. In contrast, the tetraploid ssp. cerasiformis (Madeira) displayed values similar to those obtained for the diploid ssp. guanchica (Canary Islands). Geographical isolation was associated with a high genetic differentiation at this scale. In the Canarian archipelago, the stepping-stone model of differentiation suggested in a previous study was partially supported. Within the western lineage, an east-to-west differentiation pattern was confirmed. Conversely, the easternmost populations were more related to the mainland ssp. europaea than to the western guanchica lineage. Genetic diversity across the Canarian archipelago was significantly correlated with the date of the last volcanic activity in the area/island where each population occurs. At the island scale, this pattern was not confirmed in older islands (Tenerife and Madeira), where populations were genetically homogeneous. In contrast, founder effects resulted in low genetic diversity and marked genetic differentiation among populations of the youngest island, La Palma.

Cardiopathies congénitales de l'âge adulte: nouvelle population de patients, prise en charge multidisciplinaire [Adults with congenital heart diseases: a growing population, a multidisciplinary approach].

Untill recently, congenital heart disease was considered as a childhood's disease. With improvement in pediatric survival, adults with a congenital heart disease (ACHD) represent an emerging group of patients who need specialized medical care. In 2010, the ESC published newguidelines on global and specific management of adults with congenital heart disease. ACHD centers organize appropriate medical care for these patients, promote specialist training and national scientific research in collaboration with other national ACHD centers.

An affective approach to moral motivation

Over the last few years, there has been a surge of work in a new field called "moral psychology", which uses experimental methods to test the psychological processes underlying human moral activity. In this paper, I shall follow this line of approach with the aim of working out a model of how people form value judgements and how they are motivated to act morally. I call this model an "affective picture": 'picture' because it remains strictly at the descriptive level and 'affective' because it has an important role for affects and emotions. This affective picture is grounded on a number of plausible and empirically supported hypotheses. The main idea is that we should distinguish between various kinds of value judgements by focusing on the sort of state of mind people find themselves in while uttering a judgement. "Reasoned judgements" are products of rational considerations and are based on preliminary acceptance of norms and values. On the contrary, "basic value judgements" are affective, primitive and non-reflective ways of assessing the world. As we shall see, this analysis has some consequences for the traditional internalism-externalism debate in philosophy; it highlights the fact that motivation is primarily linked to "basic value judgements" and that the judgements we openly defend might not have a particular effect on our actions, unless we are inclined to have an emotional attitude that conforms to them.

Interet de la double voie d'abord dans les blepharoplasties superieures associees aux malpositions palpebrales. [Advantages of a double approach to upper blepharoplasty associated with eyelid malpositions]

During upper blepharoplasty, myocutaneous excess and fat pads are treated using an anterior approach. Eyelid malpositions such as involutional ptosis or lid retraction could be associated and should be treated with associated procedures. Aponeurotic surgery on the levator muscle can make use of the same anterior approach, with the major difficulty of dosage. In cases of ptosis with a positive epinephrine test or minor muscular retraction, the Muller muscle-conjunctival surgery via a posterior approach seems to be more reproducible. Double-approach techniques are described.

Pragmatic approach to nutrition in the ICU: Expert opinion regarding which calorie protein target.

BACKGROUND & AIMS: Since the publications of the ESPEN guidelines on enteral and parenteral nutrition in ICU, numerous studies have added information to assist the nutritional management of critically ill patients regarding the recognition of the right population to feed, the energy-protein targeting, the route and the timing to start. METHODS: We reviewed and discussed the literature related to nutrition in the ICU from 2006 until October 2013. RESULTS: To identify safe, minimal and maximal amounts for the different nutrients and at the different stages of the acute illness is necessary. These amounts might be specific for different phases in the time course of the patient's illness. The best approach is to target the energy goal defined by indirect calorimetry. High protein intake (1.5 g/kg/d) is recommended during the early phase of the ICU stay, regardless of the simultaneous calorie intake. This recommendation can reduce catabolism. Later on, high protein intake remains recommended, likely combined with a sufficient amount of energy to avoid proteolysis. CONCLUSIONS: Pragmatic recommendations are proposed to practically optimize nutritional therapy based on recent publications. However, on some issues, there is insufficient evidence to make expert recommendations.

Derivation of soil-specific streaming potential electrical parameters from hydrodynamic characteristics of partially saturated soils

Water movement in unsaturated soils gives rise to measurable electrical potential differences that are related to the flow direction and volumetric fluxes, as well as to the soil properties themselves. Laboratory and field data suggest that these so-called streaming potentials may be several orders of magnitudes larger than theoretical predictions that only consider the influence of the relative permeability and electrical conductivity on the self potential (SP) data. Recent work has improved predictions somewhat by considering how the volumetric excess charge in the pore space scales with the inverse of water saturation. We present a new theoretical approach that uses the flux-averaged excess charge, not the volumetric excess charge, to predict streaming potentials. We present relationships for how this effective excess charge varies with water saturation for typical soil properties using either the water retention or the relative permeability function. We find large differences between soil types and the predictions based on the relative permeability function display the best agreement with field data. The new relationships better explain laboratory data than previous work and allow us to predict the recorded magnitudes of the streaming potentials following a rainfall event in sandy loam, whereas previous models predict values that are three orders of magnitude too small. We suggest that the strong signals in unsaturated media can be used to gain information about fluxes (including very small ones related to film flow), but also to constrain the relative permeability function, the water retention curve, and the relative electrical conductivity function.