Extension, diapirisme et compression en Tunisie centrale : le jebel Es Souda

Le jebel Es Souda est un brachianticlinal, au sein de l'Atlas de Tunisie centrale. Sa structure originale est la résultante d'une tectogenèse compressive polyphasée d'âge mio-plio-quaternaire, superposée à un bombement diapirique, ayant eu lieu au cours du Crétac

Chromosomal mapping of pancreatic islet morphological features and regulatory hormones in the spontaneously diabetic (Type 2) Goto-Kakizaki rat

Insulin resistance and altered endocrine pancreas function are central pathophysiological features of type 2 diabetes mellitus (T2DM). The Goto-Kakizaki (GK) rat is a model of spontaneous T2DM characterised by reduced beta cell mass and genetically determined glucose intolerance and altered insulin secretion. To identify genetic determinants of endocrine pancreas histopathology, we carried out quantitative trait locus (QTL) mapping of histological phenotypes (beta cell mass -BCM and insulin-positive cell area -IPCA) and plasma concentration of hormones and growth factors in a F2 cohort derived from GK and normoglycemic Brown Norway rats. Although IPCA and BCM in the duodenal region of the pancreas were highly positively correlated (P < 10−6), and similarly in the splenic region, both measures were poorly correlated when comparing duodenal and splenic phenotypes. Strongest evidence of linkage to pancreas morphological traits was obtained between BCM and chromosome 10 (LOD 3.2). Evidence of significant linkage (LOD 4.2) to plasma corticosterone was detected in a region of chromosome 1 distal to other QTLs previously identified in the GK. Male-specific genetic effects were detected, including linkages (LOD > 4) to growth hormome (GH) on chromosome 6 and prolactin on chromosome 17. These data suggest independent genetic control of the structure and function of ontologically different regions of the endocrine pancreas. Novel QTLs for corticosterone, prolactin and GH may contribute to diabetes in the GK. The QTLs that we have identified in this, and previous genetic studies collectively underline the complex and multiple mechanisms involved in diabetes in the GK strain

Kinetics of fragmentation-annihilation processes

We investigate the kinetics of systems in which particles of one species undergo binary fragmentation and pair annihilation. In the latter, nonlinear process, fragments react at collision to produce an inert species, causing loss of mass. We analyse these systems in the reaction-limited regime by solving a continuous model within the mean-field approximation. The rate of fragmentation, for a particle of mass $x$ to break into fragments of masses $y$ and $x-y$, has the form $x^{\lambda-1}$ ($\lambda>0$), and the annihilation rate is constant and independent of the masses of the reactants. We find that the asymptotic regime is characterized by the annihilation of small-mass clusters. The results are compared with those for a model with linear mass-loss (i.e.\ with a sink). We also study more complex models, in which the processes of fragmentation and annihilation are controlled by mutually-reacting catalysts. Both pair- and linear-annihilation are considered. Depending on the specific model and initial densities of the catalysts, the time-decay of the cluster-density can now be very unconventional and even non-universal. The interplay between the intervening processes and the existence of a scaling regime are determined by the asymptotic behaviour of the average-mass and of the mass-density, which may either decay indefinitely or tend to a constant value. We discuss further developments of this class of models and their potential applications.Comment: 16 pages(LaTeX), submitted to Phys. Rev.

Interferometric measurement of co-operative evaporation in 2D droplet arrays

The evaporation dynamics of multiple droplet arrays is important in inkjet printing and spray coating, where co-operative “shielding” effects increase the overall evaporation time. However, current measurement methods provide limited information on how individual droplets contribute to the overall dynamics. In this work, we present a simple interferometric technique for precise measurements of droplet evaporation rates, which is not possible via traditional approaches. We validate the technique on a single droplet. We then extend our analysis to ordered and random 2D arrays of droplets. We demonstrate that the evaporation rate is highly dependent on the position of the droplet within the array and its confinement. The more confined droplets exhibit lower evaporation rates. Our results of ten different configurations and well over 100 droplets are in good quantitative agreement with a recent analytical model of co-operative evaporation rates. Our approach opens up possibilities for studies of collective evaporation effects, including in areas of current importance such as sneezes and exhaled breath

Density-driven flows in evaporating binary liquid droplets

In the evaporation of microlitre liquid droplets, the accepted view is that surface tension dominates and the effect of gravity is negligible. We report, through the first use of rotating optical coherence tomography, that a change in the flow pattern and speed occurs when evaporating binary liquid droplets are tilted, conclusively showing that gravitational effects dominate the flow. We use gas chromatography to show that these flows are solutal in nature, and we establish a flow phase diagram demonstrating the conditions under which different flow mechanisms occur

How to think about health promotion ethics

Health promotion ethics is moral deliberation about health promotion and its prac­ tice. Although academics and practitioners have been writing about ethics, and especially values, in health promotion for decades, health promotion ethics is now regaining attention within the broader literature on public health ethics. Health promotion is difficult to define, and this has implications for health promotion ethics. Health promotion can be approached in two complementary ways: as a normative ideal, and as a practice. We consider the normative ideal of health promotion to be that aspect of public health practice that is particularly concerned with the equity of social arrangements: it imagines that social arrangements can be altered to make things better for everyone, whatever their health risks, and seeks to achieve this in collaboration with citizens.This raises two main ethical questions. First: what is a good society? And then: what should health promotion contribute to a good society? The practice of health promotion varies widely. Discussion of its ethical implications has addressed four main issues: the potential for health promotion to limit or increase the freedom of individuals; health promotion as a source of collective benefit; the possibility that health promotion strategies might “blame the victim” or stigmatise those who are disabled, sick or at higher risk of disease; and the importance of distributing the benefits of health promotion fairly. Different people will make different moral evaluations on each of these issues in a way that is informed by, and informs, their vision of a good society and their understanding of the ends of health promotion. We conclude that future work in health promotion ethics will require thoughtfully connecting social and political philosophy with an applied, empirically informed ethics of practice. Key Words:Ethics, health education, health promotion, moral philosophy, political philosophy, public healthNHMR

PSP_MCSVM: brainstorming consensus prediction of protein secondary structures using two-stage multiclass support vector machines

Secondary structure prediction is a crucial task for understanding the variety of protein structures and performed biological functions. Prediction of secondary structures for new proteins using their amino acid sequences is of fundamental importance in bioinformatics. We propose a novel technique to predict protein secondary structures based on position-specific scoring matrices (PSSMs) and physico-chemical properties of amino acids. It is a two stage approach involving multiclass support vector machines (SVMs) as classifiers for three different structural conformations, viz., helix, sheet and coil. In the first stage, PSSMs obtained from PSI-BLAST and five specially selected physicochemical properties of amino acids are fed into SVMs as features for sequence-to-structure prediction. Confidence values for forming helix, sheet and coil that are obtained from the first stage SVM are then used in the second stage SVM for performing structure-to-structure prediction. The two-stage cascaded classifiers (PSP_MCSVM) are trained with proteins from RS126 dataset. The classifiers are finally tested on target proteins of critical assessment of protein structure prediction experiment-9 (CASP9). PSP_MCSVM with brainstorming consensus procedure performs better than the prediction servers like Predator, DSC, SIMPA96, for randomly selected proteins from CASP9 targets. The overall performance is found to be comparable with the current state-of-the art. PSP_MCSVM source code, train-test datasets and supplementary files are available freely in public domain at: http://sysbio.icm.edu.pl/secstruct and http://code.google.com/p/cmater-bioinfo