Complémentarités et convergences de méthodes de régionalisation des précipitations : application à une région endoréique du Nord-Mexique

La connaissance des champs pluviométriques annuels est importante dans les zones arides et semi-arides où la gestion de l'eau est un exercice permanent d'aménagement de la pénurie, comme cela est le cas au Nord du Mexique.On se propose de montrer ici qu'une meilleure connaissance des disponibilités en eau peut s'appuyer sur la détermination de régions pluviométriquement homogènes à partir de diverses méthodes complémentaires ou convergentes.Pour définir des régions homogènes, on part de la répartition des stations par rapport à la régression pluviométrie/altitude. Des analyses factorielles en composantes principales et des correspondances permettent également de proposer des régions homogènes suivant des variables définies et disponibles pour toutes les stations. On s'appuie aussi sur les régimes pluviométriques pour déterminer d'autres régionalisations. Parallèlement on a pu utiliser la répartition des stations par rapport au gradient altitudinal pour créer des régions dont l'homogénéité vis-à-vis des précipitations a pu être vérifiée par la Méthode du Vecteur Régional (MVR), basée sur le principe de la pseudo-proportionnalité des données de postes proches.La comparaison des résultats obtenus par chacune des méthodes permet de constater que dans la région traitée, les limites entre régions " homogènes " sont souvent les mêmes, bien que les modes de détermination soient différents. Enfin, les différences apportent une information supplémentaire pour la compréhension des mécanismes locaux ou régionaux de la répartition des champs de pluie.Knowledge of annual rainfall is of great importance in arid and semi-arid areas, because water management is dominated by scarcity. The Nazas-Aguanaval river basin constitutes one of the main endoreic basins in Mexico (92 000 km2). It extends from the crests of the Western SierraMadre to as far as the Chihuahuan desert, in the states of Durango, Coahuila and Zacatecas. Spatial variability of rainfall is significant with annual rainfall amounts ranging from 900 mm in the higher areas of the Sierra Madre to 180 mm at the centre of the Laguna de Mayran. However, temporal variability of the precipitation amount is also appreciable, and it increases from the sub-humid areas of the mountains to the desert. The coefficient of variation for annual precipitation ranges from 0.2 in the mountains to 0.4 in Chihuahuan desert. Furthermore, in 1992, 1994, 1995, and from 1997 to 2000 severe rainfall deficits forced farmers to reduce strongly irrigated areas, thus leading to socio-economic development problems in this region. It is shown in this paper that an improvement in water availability knowledge is attainable by the determination of homogeneous rainfall regions, based on complementary or convergent methods.Rainfall distribution is a result of many factors, including the atmospheric circulation, the continental pattern, the coastal design, the location of major mountainous massifs, the distance from the ocean, and other site factors. The regionalisation of precipitation has been the subject of much research for almost all types of climates. The influence of zonal and regional factors is also determined in regional monographs where the role of local variables (relief, vegetation, general roughness of landscape, etc.) is described in relation to the large-scale circulation scheme. In most of the cases, the interpolation of values between two observations is necessary and quite difficult. Kriging is widely used for this purpose, as is co-kriging, which takes into account the topography or some other local factors and frequently gives better reconstitution of rainfall data. In order to determine the first set of homogeneous regions in northwestern Mexico, the elevation gradient of the rainfall amount was defined by a simple regression. All the stations were located with respect to the regression line and they can form apparent groups. The following relation was obtained :P=0.31 H - 133r2=0.73; n=84)(where P is annual rainfall in mm and H the altitude in m).In the same way, various statistical analysis were performed using all data available from the rainfall measurement stations, such as elevation, distance from the Pacific Ocean, exposure, annual rainfall amount, and the type of topography and vegetation cover surrounding the station. An Empirical Orthogonal Function Analysis (EOF) and a Factorial Analysis of Correspondences (FAC) revealed other kinds of regionalisation. The precipitation regime is tropical-like in spite of the latitude (25° N), but the percentage of annual precipitation in winter appeared as a segregating factor and thus was used to define the climatic geography. This was determined by a stepwise discriminant analysis, which allowed the segregation of the north-eastern area of the Nazas-Aguanaval basin. This is the dryer region of the basin because it is less exposed to monsoon fluxes and the proportion of winter rain is higher there than in the remaining basin.The main variables explaining the spatial distribution of precipitation are altitude and distance from the Pacific Ocean, as determined by both the EOF analysis and the analysis of correspondences. The grouping of stations segregated by the elevation gradient regression led to regions where the homogeneity in relation to the annual rainfall amount was tested and verified by the Regional Vector Method (RVM). This method is based on the principle of pseudo-proportionality between annual rainfall amounts at close stations.The Nazas-Aguanaval basin is divided into three climatic regions defined by precipitation: the Western Sierra Madre, the Chihuahuan desert, and a semi-arid area that is divided into two sub-regions (Middle Nazas basin and Aguanaval plateau) by the analysis of correspondences. As a result of the regional rainfall analysis, some variograms were performed to determine the length of the validity of the rainfall data. However, it appeared that a multidirectional variogram did not explain these data. The role that relief (mainly the Western Sierra Madre) plays in the spatial distribution of precipitation does not explain the length of rainfall data. Introducing the direction of mountain range into the variogram demonstrated that the relief played a significant role, and in this case the length of the rainfall variogram data was 180 km.A comparison of results obtained using each method led to the conclusion that the boundaries between homogeneous regions are often the same while the determination processes are different. Finally, all the proposed methods are complementary and the differences between all characterisations give additional information regarding the local and regional processes that explain the annual rainfall spatial distribution. Simple tools have been used to acquire a better knowledge of rainfall spatial distribution.In the case of Northern Mexico, the low density of a measurement network (rain gauges), particularly in mountainous or arid zones, is partially attenuated by the possibility of evaluating the main climatic characteristics for the different regions defined in terms of rainfall

Improving Mekong water resources investment and allocation choices

The CPWF Project PN67 “Improving Mekong Water Allocation” was a key, collaborative activity of the Mekong Program on Water, Environment and Resilience (M-POWER). The goal of contributing to water allocation policy and practice which results in a more optimal and equitable use of water by society has been pursued by research across the Mekong Region and active engagement with policymakers. The project team have examined the use of a wide range of decision-support tools, in many decision-making arenas. In doing so, they have sought to understand decision contexts and drivers

Observational Learning During Simulation-Based Training in Arthroscopy: Is It Useful to Novices?

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.OBJECTIVE: Observing experts constitutes an important and common learning experience for surgical residents before operating under direct guidance. However, studies suggest that exclusively observing experts may induce suboptimal motor learning, and watching errors from non-experts performing simple motor tasks may generate better performance. We investigated whether observational learning is transferrable to arthroscopy learning using virtual reality (VR) simulation. SETTING/DESIGN: In our surgical simulation laboratory, we compared students learning basic skills on a VR arthroscopy simulator after watching an expert video demonstration of VR arthroscopy tasks or a non-expert video demonstration of the same tasks to a Control group without video demonstration. Ninety students in 3 observing groups (expert, non-expert, and Control) subsequently completed the same procedure on a VR arthroscopy simulator. We hypothesized the non-expert-watching group would outperform the expert-watching group, and both groups to outperform the Control group. We examined performance pretest, posttest, and 1 week later. PARTICIPANTS: Participants were recruited from the final year of medical school and the very early first year of surgical residency training programs (orthopaedic surgery, urology, plastic surgery, and general surgery) at Western University (Ontario, Canada). RESULTS: All participants improved their overall performance from pretest to retention (p < 0.001). At initial retention testing, non-expert-watching group outperformed the other groups in camera path length p < 0.05 and time to completion, p < 0.05, and both the expert/non-expert groups surpassed the Control group in camera path length (p < 0.05). CONCLUSION: We suggest that error-observation may contribute to skills improvement in the non-expert-watching group. Allowing novices to observe techniques/errors of other novices may assist internalization of specific movements/skills required for effective motor performances. This study highlights the potential effect of observational learning on surgical skills acquisition and offers preliminary evidence for peer-based practice (combined non-experts and experts) as a complementary surgical motor skills training strategy.This project was supported by a Physicians׳ Services Incorporated (PSI) Foundation, Canada grant. Funds were used to pay for salary and employee benefits (LvE). The PSI Foundation did not play a role in the investigation

A two-phase flow model to simulate mold filling and saturation in Resin Transfer Molding

The final publication is available at Springer via http://dx.doi.org/10.1007/s12289-015-1225-zThis paper addresses the numerical simulation of void formation and transport during mold filling in Resin Transfer Molding (RTM). The saturation equation, based on a two-phase flow model resin/air, is coupled with Darcy s law and mass conservation to simulate the unsaturated filling flow that takes place in a RTM mold when resin is injected through the fiber bed. These equations lead to a system composed of an advection diffusion equation for saturation including capillary effects and an elliptic equation for pressure taking into account the effect of air residual saturation. The model introduces the relative permeability as a function of resin saturation. When capillary effects are omitted, the hyperbolic nature of the saturation equation and its strong coupling with Darcy equation through relative permeability represent a challenging numerical issue. The combination of the constitutive physical laws relating permeability to saturation with the coupled system of the pressure and saturation equations allows predicting the saturation profiles. The model was validated by comparison with experimental data obtained for a fiberglass reinforcement injected in a RTM mold at constant flow rate. The saturation measured as a function of time during the resin impregnation of the fiber bed compared very well with numerical predictions.The authors acknowledge financial support of the Spanish Government (Projects DPI2010-20333 and DPI2013-44903-R-AR), of the National Science and Research Council of Canada (NSERC) and of the Canada Reseach Chair (CRC) program.Gascón Martínez, ML.; García Manrique, JA.; Lebel, F.; Ruiz, E.; Trochu, F. (2016). A two-phase flow model to simulate mold filling and saturation in Resin Transfer Molding. International Journal of Material Forming. 9(2):229-239. doi:10.1007/s12289-015-1225-zS22923992Patel N, Lee LJ (1996) Modeling of void formation and removal in liquid composite molding. Part I: wettability analysis. Polym Compos 17(1):96–103Ruiz E, Achim V, Soukane S, Trochu F, Bréard J (2006) Optimization of injection flow rate to minimize micro/macro-voids formation in resin transfer molded composites. Compos Sci Technol 66(3–4):475–486Trochu F, Ruiz E, Achim V, Soukane S (2006) Advanced numerical simulation of liquid composite molding for process analysis and optimization. Compos A: Appl Sci Manuf 37(6):890–902Park CH, Lee W (2011) Modeling void formation and unsaturated flow in liquid composite molding processes: a survey and review. J Reinf Plast Compos 30(11):957–977Pillai KM (2004) Modeling the unsaturated flow in liquid composite molding processes: a review and some thoughts. J Compos Mater 38(23):2097–2118Breard J, Saouab A, Bouquet G (2003) Numerical simulation of void formation in LCM. Compos A: Appl Sci Manuf 34:517–523Breard J, Henzel Y, Trochu F, Gauvin R (2003) Analysis of dynamic flows through porous media. Part I: comparison between saturated and unsaturated flows in fibrous reinforcements. Polym Compos 24(3):391–408Parnas RS, Phelan FR Jr (1991) The effect of heterogeneous porous media on mold filling in Resin Transfer Molding. SAMPE Q 22(2):53–60Parseval DY, Pillai KM, Advani SG (1997) A simple model for the variation of permeability due to partial saturation in dual scale porous media. Transp Porous Media 27(3):243–264Pillai KM (2002) Governing equations for unsaturated flow through woven fiber mats. Part 1. Isothermal flows. Compos A: Appl Sci Manuf 33(7):1007–1019Simacek P, Advani SG (2003) A numerical model to predict fiber tow saturation during Liquid Composite Molding. Compos Sci Technol 63:1725–1736García JA, Gascón L, Chinesta F (2010) A flux limiter strategy for solving the saturation equation in RTM process simulation. Compos A: Appl Sci Manuf 41:78–82Chui WK, Glimm J, Tangerman FM, Jardine AP, Madsen JS, Donnellan TM, Leek R (1997) Process modeling in Resin Transfer Molding as a method to enhance product quality. SIAM Rev 39(4):714–727Nordlund M, Michaud V (2012) Dynamic saturation curve measurement for resin flow in glass fibre reinforcement. Compos A: Appl Sci Manuf 43:333–343García JA, Ll G, Chinesta F (2003) A fixed mesh numerical method for modelling the flow in liquid composites moulding processes using a volume of fluid technique. Comput Methods Appl Mech Eng 192(7–8):877–893García JA, Ll G, Chinesta F, Trochu F, Ruiz E (2010) An efficient solver of the saturation equation in liquid composite molding processes. Int J Mater Form 3(2):1295–1302Lebel F (2012) Contrôle de la fabrication des composites par injection sur renforts. École Polytechnique de Montréal, CanadaVan Genuchten MT (1980) Closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 44(5):892–898Buckley SE, Leverett MC (1942) Mechanism of fluid displacement in sands. Pet Trans AWME 146:107–116Lundstrom TS, Gebart BR (1994) Influence from process parameters on void formation in Resin Transfer Molding. Polym Compos 15(1):25–33Lundstrom TS (1997) Measurement of void collapse during Resin Transfer Molding. Compos A: Appl Sci Manuf 28(3):201–214Lundstrom TS, Frishfelds V, Jakovics A (2010) Bubble formation and motion in non-crimp fabrics with perturbed bundle geometry. Compos A: Appl Sci Manuf 41:83–92Lebel F, Fanaei A, Ruiz E, Trochu F (2012) Experimental characterization by fluorescence of capillary flows in the fiber tows of engineering fabrics. Open J Inorg Non-Metallic Mater 2(3):25–45Brooks RH, Corey AT (1964) Hydraulic properties of porous media. Colorado State University. Hydrology Papers 1–37Corey AT (1954) The interrelation between gas and oil relative permeabilities. Prod Monthly 19(1):38–4

Cystamine/cysteamine rescues the dopaminergic system and shows neurorestorative properties in an animal model of Parkinson's disease.

The neuroprotective properties of cystamine identified in pre-clinical studies have fast-tracked this compound to clinical trials in Huntington's disease, showing tolerability and benefits on motor symptoms. We tested whether cystamine could have such properties in a Parkinson's disease murine model and now provide evidence that it can not only prevent the neurodegenerative process but also can reverse motor impairments created by a 6-hydroxydopamine lesion 3weeks post-surgery. Importantly, we report that cystamine has neurorestorative properties 5weeks post-lesion as seen on the number of nigral dopaminergic neurons which is comparable with treatments of cysteamine, the reduced form of cystamine used in the clinic, as well as rasagiline, increasingly prescribed in early parkinsonism. All three compounds induced neurite arborization of the remaining dopaminergic cells which was further confirmed in ex vivo dopaminergic explants derived from Pitx3-GFP mice. The disease-modifying effects displayed by cystamine/cysteamine would encourage clinical testing

Unidimensional scales for fears of cancer recurrence and their psychometric properties : the FCR4 and FCR7

Funding: Support was received from SUPAC (NCRI) Early Career Fund to complete this study. NCRI Supportive & Palliative Care (SuPaC) Research Collaboratives Capacity Building Grant Scheme: G Ozakinci (PI), G Humphris, M Sharpe.Background:  The assessment of fear of recurrence (FCR) is crucial for understanding an important psychological state in patients diagnosed and treated for cancer. The study aim was to determine psychometric details of a seven question self-report scale (FCR7) and a short form (FCR4) based upon items already used in various extensive measures of FCR. Methods:  Two consecutive samples of patients (breast and colorectal) were recruited from a single specialist cancer centre. The survey instrument contained the FCR7 items, Hospital Anxiety and Depression Scale (HADS), and demographic details. Clinical information was obtained from patient hospital records. Statistical analyses were performed using classical test and item response theory approaches, to demonstrate unidimensional factor structure and testing key parameters. Construct validity was inspected through nomological and theoretical prediction. Results:  Internal consistency was demonstrated by alpha coefficients (FCR4: 0.93 and FCR7: 0.92). Both scales (FCR7 & FCR4) were associated with the HADs subscales as predicted. Patients who experienced chemotherapy, minor aches/pains, thought avoidance of cancer and high cancer risk belief were more fearful. Detailed inspection of item responses profile provided some support for measurement properties of scales. Conclusion: The internal consistency, and pattern of key associations and discriminability indices provided positive psychometric evidence for these scales. The brief measures of FCR may be considered for audit, screening or routine use in clinical service and research investigations.Publisher PDFPeer reviewe

Expanding Stereochemical and Skeletal Diversity Using Petasis Reactions and 1,3-Dipolar Cycloadditions

A short and modular synthetic pathway using intramolecular 1,3-dipolar cycloaddition reactions and yielding functionalized isoxazoles, isoxazolines, and isoxazolidines is described. The change in shape of previous compounds and those in this study is quantified and compared using principal moment-of-inertia shape analysis.Chemistry and Chemical Biolog

Adolescent brain maturation and cortical folding: evidence for reductions in gyrification

Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM), increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area. In the current study, we acquired high-resolution (3 Tesla) magnetic resonance imaging (MRI) data from 79 healthy subjects (34 males and 45 females) between the ages of 12 and 23 years and performed whole brain analysis of cortical folding patterns with the gyrification index (GI). In addition to GI-values, we obtained estimates of cortical thickness, surface area, GM and white matter (WM) volume which permitted correlations with changes in gyrification. Our data show pronounced and widespread reductions in GI-values during adolescence in several cortical regions which include precentral, temporal and frontal areas. Decreases in gyrification overlap only partially with changes in the thickness, volume and surface of GM and were characterized overall by a linear developmental trajectory. Our data suggest that the observed reductions in GI-values represent an additional, important modification of the cerebral cortex during late brain maturation which may be related to cognitive development