Dynamo Tests for Stratification Below the Core-Mantle Boundary

NASA Astrophysics Data System (ADS)

Olson, P.; Landeau, M.

2017-12-01

Evidence from seismology, mineral physics, and core dynamics points to a layer with an overall stable stratification in the Earth's outer core, possibly thermal in origin, extending below the core-mantle boundary (CMB) for several hundred kilometers. In contrast, energetic deep mantle convection with elevated heat flux implies locally unstable thermal stratification below the CMB in places, consistent with interpretations of non-dipole geomagnetic field behavior that favor upwelling flows below the CMB. Here, we model the structure of convection and magnetic fields in the core using numerical dynamos with laterally heterogeneous boundary heat flux in order to rationalize this conflicting evidence. Strongly heterogeneous boundary heat flux generates localized convection beneath the CMB that coexists with an overall stable stratification there. Partially stratified dynamos have distinctive time average magnetic field structures. Without stratification or with stratification confined to a thin layer, the octupole component is small and the CMB magnetic field structure includes polar intensity minima. With more extensive stratification, the octupole component is large and the magnetic field structure includes intense patches or high intensity lobes in the polar regions. Comparisons with the time-averaged geomagnetic field are generally favorable for partial stratification in a thin layer but unfavorable for stratification in a thick layer beneath the CMB.

Principal Stratification — Uses and Limitations

PubMed Central

VanderWeele, Tyler J

2011-01-01

Pearl (2011) asked for the causal inference community to clarify the role of the principal stratification framework in the analysis of causal effects. Here, I argue that the notion of principal stratification has shed light on problems of non-compliance, censoring-by-death, and the analysis of post-infection outcomes; that it may be of use in considering problems of surrogacy but further development is needed; that it is of some use in assessing “direct effects”; but that it is not the appropriate tool for assessing “mediation.” There is nothing within the principal stratification framework that corresponds to a measure of an “indirect” or “mediated” effect. PMID:21841939

Eigenmode resonance in a two-layer stratification

NASA Astrophysics Data System (ADS)

Kanda, Isao; Linden, P. F.

2002-06-01

In this paper, we study the velocity field at the density interface of a two-layer stratification system when the flow is forced at the mid-depth of the lower layer by the source sink forcing method. It is known that, in a sufficiently strong linear stratification, the source sink forcing in certain configurations produces a single-vortex pattern which corresponds to the lowest eigenmode of the Helmholtz equation (Kanda & Linden 2001). Two types of forcing configuration are used for the two-layer experiments: one that leads to a steady single-vortex pattern in a linear stratification, and one that results in an unsteady irregular state. Strong single-vortex patterns appear intermittently for the former configurations despite the absence of stratification at the forcing height. When the single-vortex pattern occurs at the density interface, a similar flow field extends down to the forcing height. The behaviour is explained as the coupling of the resonant eigenmode at the interface with the horizontal component of the forcing jets. The results show that stratification can organise a flow, even though it is forced by an apparently random three-dimensional forcing.

Stratificational Grammar.

ERIC Educational Resources Information Center

Algeo, John

1968-01-01

According to the author, most grammarians have been writing stratificational grammars without knowing it because they have dealt with units that are related to one another, but not simply as a whole to its parts, or as a class to its members. The question, then, is not whether a grammar is stratified but whether it is explicitly stratified. This…

A reconceptualization of age stratification in China.

PubMed

Yin, P; Lai, K H

1983-09-01

Using the concepts of age stratification theory--age effect, cohort effect, and subcohort differences--this paper provides a new perspective on age stratification in China. Currently, the literature suggests that the status of elderly people declined after the Communist Revolution and will further decline with modernization. We discuss the problems with this perspective and argue, instead, that the status of elderly adults did not decline for the majority of the aged during the Maoist years. Rather, the most important change in the age stratification system during the Maoist years was the change in the criterion of age stratification--from age differences to cohort and subcohort differences. Furthermore, the subcohort of elderly adults who suffered the most status decline during the Maoist years--the bourgeoisie--may actually enjoy an increase in status with the recent modernization impetus. Research suggestions from this new perspective are discussed.

Le syndrome d’Usher: à propos d’une observation

PubMed Central

Daoudi, Chama; boutimzine, Noureddine; Haouzi, Samia El; Lezrek, Omar; Tachfouti, Samira; Lezrek, Mounir; Laghmari, Mina; Daoudi, Rajae

2017-01-01

Résumé Le syndrome d'Usher est une maladie génétique comportant une double atteinte sensorielle (auditive et visuelle) appelée surdicécité. Nous rapportons l'observation d'un patient de 50 ans, issue d'un mariage consanguin présentant une surdité congénitale avec une fonction vestibulaire normale et une rétinopathie pigmentaire responsable d'une baisse bilatérale de l'acuité visuelle apparue vers l'âge de 16 ans. Cette association compose le type 2 du syndrome d'Usher, affection rare de transmission autosomique récessive. La chirurgie de la cataracte a permis une amélioration de l'acuité visuelle chez ce patient. PMID:28979619

Stratification and mobility in contemporary Egypt.

PubMed

Nagi, Saad Z; Nagi, Omar

2011-01-01

The objectives in this statement are to characterize and explain the patterns of change in stratification and mobility in Egypt, over the last half century, by placing them within conceptual, explanatory, and historical contexts. First, literature relevant to the primary concepts of "class" and "status", is reviewed. Second, four institutions whose influence is fundamental in shaping these patterns are identified to form an explanatory context: family, polity, economy, and education. And third, an historical account is presented to demonstrate the interplay of these institutions and their consequences for stratification and mobility. For this, four periods are identified that are marked by change in the dominance of institutions and their corresponding influence on stratification and mobility. In addition to data available in relevant literature, this analysis utilizes primary data generated through a national probability household survey.

Mode de révélation particulier d'une tumeur brune chez une patiente hémodialysée chronique

PubMed Central

El Harraqui, Ryme; Karimi, Ilham; Chemlal, Abdeljalil; Ismaili, Fatiha Alaoui; Haddiya, Intissar

2014-01-01

Les tumeurs brunes constituent une complication rare mais sévère de la dialyse, le plus souvent asymptomatique. Nous rapportons le cas d'une patiente dont le mode de révélation de la tumeur brune fut atypique. Observation médicale: Madame F. est une patiente hémodialysée chronique depuis 14 ans suite à une néphropathie indéterminée. Sur le plan phosphocalcique, elle présente une ostéoporose depuis plus de 10 ans, ainsi qu'une hyperparathyroïdie secondaire. A la date du 24 octobre 2013, elle rapporte qu'elle a constaté la présence d'une petite « bosse » pariétale, apparue de façon spontanée la veille, sans notion de traumatisme. A l'examen clinique, nous trouvons une petite tuméfaction de 2cm de diamètre environs, de consistance dure, indolore, mobile par rapport au cuir chevelu. L’échographie a conclu à un lipome. Le lendemain matin, la patiente entre dans un état de coma profond. Le scanner cérébral a révélé la présence d'un hématome extradural associé à un hématome superficiel extra-crânien en regard d'une lyse de l'os pariétal, qui est en fait une tumeur brune. La patiente est transférée en réanimation où elle décède dans la journée. PMID:25422698

The influence of atmospheric stratification on scatterometer data

NASA Technical Reports Server (NTRS)

Louis, Jean-Francois; Hoffman, Ross N.

1989-01-01

The effects of atmospheric stratification and the stability of the atmospheric stratification on the scatterometer data measuring surface winds over the ocean were investigated using the boundary layer model developed by Louis (1979). A variational analysis method is proposed, which allows direct assimilation of scatterometer data. It is shown that the effect of the stability of atmospheric stratification on the wind increment is relatively small. However, it is a systematic effect, and neglecting it would consistently underestimate the winds in stable regions.

Validation materielle d'une architecture generique de reseaux avioniques basee sur une gestion modulaire de la redondance

NASA Astrophysics Data System (ADS)

Tremblay, Jose-Philippe

Les systemes avioniques ne cessent d'evoluer depuis l'apparition des technologies numeriques au tournant des annees 60. Apres le passage par plusieurs paradigmes de developpement, ces systemes suivent maintenant l'approche " Integrated Modular Avionics " (IMA) depuis le debut des annees 2000. Contrairement aux methodes anterieures, cette approche est basee sur une conception modulaire, un partage de ressources generiques entre plusieurs systemes et l'utilisation plus poussee de bus multiplexes. La plupart des concepts utilises par l'architecture IMA, bien que deja connus dans le domaine de l'informatique distribuee, constituent un changement marque par rapport aux modeles anterieurs dans le monde avionique. Ceux-ci viennent s'ajouter aux contraintes importantes de l'avionique classique telles que le determinisme, le temps reel, la certification et les cibles elevees de fiabilite. L'adoption de l'approche IMA a declenche une revision de plusieurs aspects de la conception, de la certification et de l'implementation d'un systeme IMA afin d'en tirer profit. Cette revision, ralentie par les contraintes avioniques, est toujours en cours, et offre encore l'opportunite de developpement de nouveaux outils, methodes et modeles a tous les niveaux du processus d'implementation d?un systeme IMA. Dans un contexte de proposition et de validation d'une nouvelle architecture IMA pour un reseau generique de capteurs a bord d?un avion, nous avons identifie quelques aspects des differentes approches traditionnelles pour la realisation de ce type d?architecture pouvant etre ameliores. Afin de remedier a certaines des differentes lacunes identifiees, nous avons propose une approche de validation basee sur une plateforme materielle reconfigurable ainsi qu'une nouvelle approche de gestion de la redondance pour l'atteinte des cibles de fiabilite. Contrairement aux outils statiques plus limites satisfaisant les besoins pour la conception d'une architecture federee, notre approche de

Optimized endogenous post-stratification in forest inventories

Treesearch

Paul L. Patterson

2012-01-01

An example of endogenous post-stratification is the use of remote sensing data with a sample of ground data to build a logistic regression model to predict the probability that a plot is forested and using the predicted probabilities to form categories for post-stratification. An optimized endogenous post-stratified estimator of the proportion of forest has been...

Revealing the timing of ocean stratification using remotely sensed ocean fronts

NASA Astrophysics Data System (ADS)

Miller, Peter I.; Loveday, Benjamin R.

2017-10-01

Stratification is of critical importance to the circulation, mixing and productivity of the ocean, and is expected to be modified by climate change. Stratification is also understood to affect the surface aggregation of pelagic fish and hence the foraging behaviour and distribution of their predators such as seabirds and cetaceans. Hence it would be prudent to monitor the stratification of the global ocean, though this is currently only possible using in situ sampling, profiling buoys or underwater autonomous vehicles. Earth observation (EO) sensors cannot directly detect stratification, but can observe surface features related to the presence of stratification, for example shelf-sea fronts that separate tidally-mixed water from seasonally stratified water. This paper describes a novel algorithm that accumulates evidence for stratification from a sequence of oceanic front maps, and discusses preliminary results in comparison with in situ data and simulations from 3D hydrodynamic models. In certain regions, this method can reveal the timing of the seasonal onset and breakdown of stratification.

Diffusion and plasticity at high temperature

NASA Astrophysics Data System (ADS)

Philibert, J.

1991-06-01

High temperature plastic deformation requires atomic migration whatever the mechanism of deformation. The constitutive equations contain a diffusion coefficient and the deformation rate follows an Arrhenius law. This paper will only discuss the case of viscous creep in order to elucidate the nature of the diffusion processes and the expression of the diffusion coefficient involved in alloys or compounds. La déformation plastique à haute température met en jeu des migrations atomiques, quel que soit le mécanisme de déformation. Les lois de comportement contiennent donc un coefficient de diffusion et la vitesse de déformation obéit à une loi d'Arrhenius. Dans cet article, qui ne conceme qu'un seul type de déformation, lefluage visqueux, on s'efforce de préciser la nature des processus de diffusion et du coefficient de diffusion mis en jeu dans le cas des alliages et des composés.

Etude des phenomenes chimiques au contact entre le bloc cathodique et la barre collectrice d'une cellule d'electrolyse d'aluminium

NASA Astrophysics Data System (ADS)

Lebeuf, Martin

égréger l'influence des différents paramètres en jeu. L'analyse des résultats de l'ensemble de ces tests a permis de constater différents phénomènes au contact bloc-barre, dont la présence systématique de NaF et, surtout, de β-Al 2O3. Outre la carburation inévitable de la barre collectrice, la formation d'une couche Fe-Al a aussi été observée, favorisée par une pénétration rapide du bain électrolytique dans la cathode ainsi que par une composition de bain acide en surface de la barre. Cette couche comportait par ailleurs des cristaux de β-Al 2O3 pouvant nuire à sa conductivité électrique. Ensuite, à des ratios de bain entre 2.5 et 4.9, une mince couche contenant les éléments Al et N peut se former en surface de la barre. Pour un bain très basique (> 6.0), c'est plutôt une couche Na 2O qui a été observée. En conditions d'électrolyse mais sans une pénétration rapide du bain dans la cathode, du Na a pu carrément pénétrer dans la barre collectrice, préférentiellement avec le carbone. De plus, de la corrosion ainsi que des couches de fer et d'oxyde de fer peuvent se former sur la barre et potentiellement dégrader la qualité du contact électrique. Pour la suite des travaux, des mesures de résistivité ainsi que l'analyse des échantillons industriels permettraient d'évaluer l'impact de ces phénomènes sur la qualité du contact. Mots-clés : Électrolyse, aluminium, Hall-Héroult, interface barre-cathode, bain électrolytique.

Study protocol: the JEU cohort study--transversal multiaxial evaluation and 5-year follow-up of a cohort of French gamblers.

PubMed

Challet-Bouju, Gaëlle; Hardouin, Jean-Benoit; Vénisse, Jean-Luc; Romo, Lucia; Valleur, Marc; Magalon, David; Fatséas, Mélina; Chéreau-Boudet, Isabelle; Gorsane, Mohamed-Ali; Grall-Bronnec, Marie

2014-08-20

There is abundant literature on how to distinguish problem gambling (PG) from social gambling, but there are very few studies of the long-term evolution of gambling practice. As a consequence, the correlates of key state changes in the gambling trajectory are still unknown. The objective of the JEU cohort study is to identify the determinants of key state changes in the gambling practice, such as the emergence of a gambling problem, natural recovery from a gambling problem, resolution of a gambling problem with intermediate care intervention, relapses or care recourse. The present study was designed to overcome the limitations of previous cohort study on PG. Indeed, this longitudinal case-control cohort is the first which plans to recruit enough participants from different initial gambling severity levels to observe these rare changes. In particular, we plan to recruit three groups of gamblers: non-problem gamblers, problem gamblers without treatment and problem gamblers seeking treatment.Recruitment takes place in various gambling places, through the press and in care centers. Cohort participants are gamblers of both sexes who reported gambling on at least one occasion in the previous year and who were aged between 18 and 65. They were assessed through a structured clinical interview and self-assessment questionnaires at baseline and then once a year for five years. Data collection comprises sociodemographic characteristics, gambling habits (including gambling trajectory), the PG section of the DSM-IV, the South Oaks Gambling Screen, the Gambling Attitudes and Beliefs Survey - 23, the Mini International Neuropsychiatric Interview, the Wender-Utah Rating Scale-Child, the Adult ADHD Self-report Scale, somatic comorbidities (especially current treatment and Parkinson disease) and the Temperament and Character Inventory - 125. The JEU cohort study is the first study which proposes to identify the predictive factors of key state changes in gambling practice. This is

Density stratification effects in sand-bed rivers

USGS Publications Warehouse

Wright, S.; Parker, G.

2004-01-01

In this paper the effects of density stratification in sand-bed rivers are studied by the application of a model of vertical velocity and concentration profiles, coupled through the use of a turbulence closure that retains the buoyancy terms. By making the governing equations dimensionless, it is revealed that the slope is the additional dimensionless parameter introduced by inclusion of the buoyancy terms. The primary new finding is that in general density stratification effects tend to be greater in large, low-slope rivers than in their smaller, steeper brethren. Under high flow conditions the total suspended load and size distribution of suspended sediment can be significantly affected by density stratification, and should be accounted for in any general theory of suspended transport. ?? ASCE.

Aménorrhée chimio induite chez une population marocaine: à propos d'une cohorte retrospective

PubMed Central

Brahmi, Sami Aziz; Ziani, Fatima Zahra; Youssef, Seddik; Afqir, Said

2016-01-01

Introduction Le cancer du sein est un des cancers les plus fréquents chez la femme en pré ménopause et son traitement peut compromettre la fertilité. En effet, la chimiothérapie utilisée dans le cancer du sein peut conduire à une aménorrhée transitoire ou permanente chez les femmes non ménopausées. Méthodes Nous avons mené une étude rétrospective au service d'oncologie médicale du CHU Mohammed VI d'Oujda sur une période de 3 ans allant de janvier 2009 à décembre 2011 incluant les patientes jeunes ayant un cancer du sein localisé, pour étudier l'incidence de l'aménorrhée chimio-induite (ACI), ainsi que les facteurs prédictifs intervenant dans sa survenue. Résultats Dans notre série 74% de nos patientes ont présenté une ACI et 33.6% de nos patientes ont présenté une aménorrhée chimio-induite définitive. Plusieurs facteurs ont été étudiés à la recherche d’élément prédictifs de la survenue de l'aménorrhée. Concernant le facteur âge, l'analyse a montré que les femmes avec un âge supérieur à 40 ans étaient plus susceptibles de présenter une aménorrhée que celles avec un âge inférieur à 40 avec un pourcentage de 95,7% versus 56,1% avec une différence significative (p = 0.003). Conclusion L'incidence dans notre étude de l'ACI semble comparable à celle retrouvé dans la littérature, l’âge dans notre étude est le facteur prédictif le plus prédominant dans sa survenue. PMID:27642399

Educational Stratification in Russia during the Soviet Period.

ERIC Educational Resources Information Center

Gerber, Theodore P.; Hout, Michael

1995-01-01

Maintains that, in spite of state efforts to reduce educational inequities, stratification actually increased during the Soviet period. Removing gender preferences for men corrected some inequity. However, parents' education, occupation, and geographical origin contributed to the stratification. Contains a concise history of Soviet educational…

A new stratification of mourning dove call-count routes

USGS Publications Warehouse

Blankenship, L.H.; Humphrey, A.B.; MacDonald, D.

1971-01-01

The mourning dove (Zenaidura macroura) call-count survey is a nationwide audio-census of breeding mourning doves. Recent analyses of the call-count routes have utilized a stratification based upon physiographic regions of the United States. An analysis of 5 years of call-count data, based upon stratification using potential natural vegetation, has demonstrated that this uew stratification results in strata with greater homogeneity than the physiographic strata, provides lower error variance, and hence generates greatet precision in the analysis without an increase in call-count routes. Error variance was reduced approximately 30 percent for the contiguous United States. This indicates that future analysis based upon the new stratification will result in an increased ability to detect significant year-to-year changes.

Education and Social Stratification Processes in Comparative Perspective.

ERIC Educational Resources Information Center

Kerckhoff, Alan C.

2001-01-01

Discusses three characteristics of educational systems that have been used to explain social stratification processes: stratification, standardization, and vocational specificity. Describes how these characteristics affect the movement of students through school and into the labor force in France, Germany, Great Britain, and the United States.…

UNED OER Experience: From OCW to Open UNED

ERIC Educational Resources Information Center

Ros, Salvador; Hernández, Roberto; Read, Timothy; Artacho, Miguel Rodriguez; Pastor, Rafael; Orueta, Gabriel Diaz

2014-01-01

Much has happened with open software, there has been a global attitude shift in the education community toward the open sharing of educational courses and resources. As the largest public distance education university in Spain, Universidad Nacional de Educacio´n a Distancia (UNED) has had a clear commitment to open learning and content since its…

The role stratification on Indian ocean mixing under global warming

NASA Astrophysics Data System (ADS)

Praveen, V.; Valsala, V.; Ravindran, A. M.

2017-12-01

The impact of changes in Indian ocean stratification on mixing under global warming is examined. Previous studies on global warming and associated weakening of winds reported to increase the stratification of the world ocean leading to a reduction in mixing, increased acidity, reduced oxygen and there by a reduction in productivity. However this processes is not uniform and are also modulated by changes in wind pattern of the future. Our study evaluate the role of stratification and surface fluxes on mixing focusing northern Indian ocean. A dynamical downscaling study using Regional ocean Modelling system (ROMS) forced with stratification and surface fluxes from selected CMIP5 models are presented. Results from an extensive set of historical and Representative Concentration Pathways 8.5 (rcp8.5) scenario simulations are used to quantify the distinctive role of stratification on mixing.

Patient characteristics and stratification in medical treatment studies for metastatic colorectal cancer: a proposal for standardization of patient characteristic reporting and stratification.

PubMed

Sorbye, H; Köhne, C-H; Sargent, D J; Glimelius, B

2007-10-01

Prognostic factors have the potential to determine the survival of patients to a greater extent than current antineoplastic agents. Despite this knowledge, there is no consensus on, first, what patient characteristics to report and, second, what stratification factors to use in metastatic colorectal cancer trials. Seven leading oncology and medical journals were reviewed for phase II and III publications reporting on medical treatment of metastatic colorectal cancer patients during 2001-2005. One hundred and forty-three studies with 21 214 patients were identified. The reporting of patient characteristics and use of stratification was noted. Age, gender, performance status, metastases location, sites and adjuvant chemotherapy were often reported (99-63%). Laboratory values as alkaline phosphatase, lactate dehydrogenase and white blood cell count, repeatedly found to be of prognostic relevance, were rarely reported (5-9%). Stratification was used in all phase III trials; however, only study centre was used with any consistency. There is considerable inconsistency in the reporting of patient characteristics and use of stratification factors in metastatic colorectal cancer trials. We propose a standardization of patient characteristics reporting and stratification factors. A common set of characteristics and strata will aid in trial reporting, interpretation and future meta-analyses.

Effects of Density Stratification in Compressible Polytropic Convection

NASA Astrophysics Data System (ADS)

Manduca, Cathryn M.; Anders, Evan H.; Bordwell, Baylee; Brown, Benjamin P.; Burns, Keaton J.; Lecoanet, Daniel; Oishi, Jeffrey S.; Vasil, Geoffrey M.

2017-11-01

We study compressible convection in polytropically-stratified atmospheres, exploring the effect of varying the total density stratification. Using the Dedalus pseudospectral framework, we perform 2D and 3D simulations. In these experiments we vary the number of density scale heights, studying atmospheres with little stratification (1 density scale height) and significant stratification (5 density scale heights). We vary the level of convective driving (quantified by the Rayleigh number), and study flows at similar Mach numbers by fixing the initial superadiabaticity. We explore the differences between 2D and 3D simulations, and in particular study the equilibration between different reservoirs of energy (kinetic, potential and internal) in the evolved states.

Principal Stratification — a Goal or a Tool?

PubMed Central

Pearl, Judea

2011-01-01

Principal stratification has recently become a popular tool to address certain causal inference questions, particularly in dealing with post-randomization factors in randomized trials. Here, we analyze the conceptual basis for this framework and invite response to clarify the value of principal stratification in estimating causal effects of interest. PMID:21556288

Cancer Stratification by Molecular Imaging

PubMed Central

Weber, Justus; Haberkorn, Uwe; Mier, Walter

2015-01-01

The lack of specificity of traditional cytotoxic drugs has triggered the development of anticancer agents that selectively address specific molecular targets. An intrinsic property of these specialized drugs is their limited applicability for specific patient subgroups. Consequently, the generation of information about tumor characteristics is the key to exploit the potential of these drugs. Currently, cancer stratification relies on three approaches: Gene expression analysis and cancer proteomics, immunohistochemistry and molecular imaging. In order to enable the precise localization of functionally expressed targets, molecular imaging combines highly selective biomarkers and intense signal sources. Thus, cancer stratification and localization are performed simultaneously. Many cancer types are characterized by altered receptor expression, such as somatostatin receptors, folate receptors or Her2 (human epidermal growth factor receptor 2). Similar correlations are also known for a multitude of transporters, such as glucose transporters, amino acid transporters or hNIS (human sodium iodide symporter), as well as cell specific proteins, such as the prostate specific membrane antigen, integrins, and CD20. This review provides a comprehensive description of the methods, targets and agents used in molecular imaging, to outline their application for cancer stratification. Emphasis is placed on radiotracers which are used to identify altered expression patterns of cancer associated markers. PMID:25749472

Pathomimie de l'enfant: à propos d'une observation

PubMed Central

Abilkassem, Rachid; Dini, Nezha; Ourai, Hakim; Kmari, Mohamed; Agadr, Aomar

2013-01-01

La pathomimie cutanée se définit comme une maladie factice, provoquée dans un etat de conscience claire par le patient lui-même, au niveau du revêtement cutanéo-muqueux et/ou des phanères. Rare chez l'enfant, il s'agit d'une manifestation psychopathologique potentiellement grave et souvent difficile à prendre en charge. Nous rapportons le cas d'une fillette de 10 ans présentant une pathomimie sous forme de lésions excoriées multiples du visage. PMID:23504605

Near-Surface Effects of Free Atmosphere Stratification in Free Convection

NASA Astrophysics Data System (ADS)

Mellado, Juan Pedro; van Heerwaarden, Chiel C.; Garcia, Jade Rachele

2016-04-01

The effect of a linear stratification in the free atmosphere on near-surface properties in a free convective boundary layer (CBL) is investigated by means of direct numerical simulation. We consider two regimes: a neutral stratification regime, which represents a CBL that grows into a residual layer, and a strong stratification regime, which represents the equilibrium (quasi-steady) entrainment regime. We find that the mean buoyancy varies as z^{-1/3}, in agreement with classical similarity theory. However, the root-mean-square (r.m.s.) of the buoyancy fluctuation and the r.m.s. of the vertical velocity vary as z^{-0.45} and ln z, respectively, both in disagreement with theory. These scaling laws are independent of the stratification regime, but the depth over which they are valid depends on the stratification. In the strong stratification regime, this depth is about 20 to 25 % of the CBL depth instead of the commonly used 10 %, which we only observe under neutral conditions. In both regimes, the near-surface flow structure can be interpreted as a hierarchy of circulations attached to the surface. Based on this structure, we define a new near-surface layer in free convection, the plume-merging layer, that is conceptually different from the constant-flux layer. The varying depth of the plume-merging layer depending on the stratification accounts for the varying depth of validity of the scaling laws. These findings imply that the buoyancy transfer law needed in mixed-layer and single-column models is well described by the classical similarity theory, independent of the stratification in the free atmosphere, even though other near-surface properties, such as the r.m.s. of the buoyancy fluctuation and the r.m.s. of the vertical velocity, are inconsistent with that theory.

Numerical Study of Wake Vortex Behavior in Turbulent Domains with Ambient Stratification

NASA Technical Reports Server (NTRS)

Switzer, George F.; Proctor, Fred H.

2000-01-01

A three-dimensional large eddy simulation model is used to investigate the sensitivity of ambient stratification with turbulence on the behavior of aircraft wake vortices. Modeled ambient turbulence levels range from very weak to moderate, and stratification levels range from strongly stable to unstable. The results of profound significance from this study are: 1) very little sensitivity between vortex linking time and the level of stratification, 2) the mean vortex separation remained nearly constant regardless of stratification and turbulence (at least prior to linking), 3) the wake vortices did not rise regardless of the level of stratification, and 4) for very strong stratification, the vortex stopped descending and quickly dissipated even before vortex linking could occur. These results are supported by experimental data and are contrary to conclusions from other numerical studies that assume laminar flow and/or relatively-low Reynolds numbers.

Polar ocean stratification in a cold climate.

PubMed

Sigman, Daniel M; Jaccard, Samuel L; Haug, Gerald H

2004-03-04

The low-latitude ocean is strongly stratified by the warmth of its surface water. As a result, the great volume of the deep ocean has easiest access to the atmosphere through the polar surface ocean. In the modern polar ocean during the winter, the vertical distribution of temperature promotes overturning, with colder water over warmer, while the salinity distribution typically promotes stratification, with fresher water over saltier. However, the sensitivity of seawater density to temperature is reduced as temperature approaches the freezing point, with potential consequences for global ocean circulation under cold climates. Here we present deep-sea records of biogenic opal accumulation and sedimentary nitrogen isotopic composition from the Subarctic North Pacific Ocean and the Southern Ocean. These records indicate that vertical stratification increased in both northern and southern high latitudes 2.7 million years ago, when Northern Hemisphere glaciation intensified in association with global cooling during the late Pliocene epoch. We propose that the cooling caused this increased stratification by weakening the role of temperature in polar ocean density structure so as to reduce its opposition to the stratifying effect of the vertical salinity distribution. The shift towards stratification in the polar ocean 2.7 million years ago may have increased the quantity of carbon dioxide trapped in the abyss, amplifying the global cooling.

Breakup of last glacial deep stratification in the South Pacific

NASA Astrophysics Data System (ADS)

Basak, Chandranath; Fröllje, Henning; Lamy, Frank; Gersonde, Rainer; Benz, Verena; Anderson, Robert F.; Molina-Kescher, Mario; Pahnke, Katharina

2018-02-01

Stratification of the deep Southern Ocean during the Last Glacial Maximum is thought to have facilitated carbon storage and subsequent release during the deglaciation as stratification broke down, contributing to atmospheric CO2 rise. Here, we present neodymium isotope evidence from deep to abyssal waters in the South Pacific that confirms stratification of the deepwater column during the Last Glacial Maximum. The results indicate a glacial northward expansion of Ross Sea Bottom Water and a Southern Hemisphere climate trigger for the deglacial breakup of deep stratification. It highlights the important role of abyssal waters in sustaining a deep glacial carbon reservoir and Southern Hemisphere climate change as a prerequisite for the destabilization of the water column and hence the deglacial release of sequestered CO2 through upwelling.

Une fistule recto-vaginale rentrant dans le cadre d'un syndrome de Currarino

PubMed Central

Idrissi, Mounia Lakhdar; Babakhoya, Abdeladim; Bouabdellah, Youssef; Hida, Mostapha

2011-01-01

Le syndrome de Currarino (SC) est défini par une triade rassemblant une malformation ano-rectale, une agénésie sacrée et une tumeur pré-sacrée. Nous rapportons le cas d'une fille de 4 ans et demi ayant été admise en consultation de gastro-entérologie pédiatrique pour constipation avec issue de selle à travers un orifice vulvaire. La radiographie du rachis avait montré une agénésie sacrée. Le fistulo-scanner a mis en évidence une fistule recto-vaginale et l'IRM pelvienne a confirmé l'agénésie sacrée et a retrouvé une méningocèle antérieure. La découverte d'une malformation ano-rectale doit faire chercher une autre anomalie de la triade de Currarino. Cette affection, rare, nécessite une prise en charge médico-chirurgicale assez complexe. PMID:22384297

Toxoplasmose oculaire atypique chez une femme congolaise de 72 ans: à propos d'une observation

PubMed Central

Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Eric, Kasamba Ilunga; Socrate, Kapalu Mwangala; Sebastien, Mbuyi Musanzayi; Philippe, Cilundika Mulenga; Leon, Kabamba Ngombe; Bruno, Iye Ombamba Kayimba; Gaby, Chenge Borasisi

2015-01-01

Les auteurs rapportent un cas de toxoplasmose oculaire binoculaire, rarement décrit dans la littérature, chez une personne âgée de 72 ans, de sexe féminin, à laquelle s'associe une rétinite pigmentaire unilatérale. Cette observation permet d'attirer l'attention de la communauté scientifique sur les autres formes ou variétés de présentation moins courantes, « atypiques », pouvant être rencontrées ou associées à la toxoplasmose oculaire. PMID:26958130

Arctic Planning Scenarios: Scenario #1: Defence Scenario

DTIC Science & Technology

2011-07-01

scénarios pour la planification future et d’aider les commandements opérationnels dans leur interaction avec les autres centres d’opérations. Ce rapport...scénarios pour la planification future. Ce rapport présente l’un des scénarios, qui est axé sur une intervention centrée sur la défense. Résultats : Le...et d’autres personnes qui participent à la planification de la défense du Canada auront besoin d’un jeu complet de scénarios pour évaluer les

A probabilistic topic model for clinical risk stratification from electronic health records.

PubMed

Huang, Zhengxing; Dong, Wei; Duan, Huilong

2015-12-01

Risk stratification aims to provide physicians with the accurate assessment of a patient's clinical risk such that an individualized prevention or management strategy can be developed and delivered. Existing risk stratification techniques mainly focus on predicting the overall risk of an individual patient in a supervised manner, and, at the cohort level, often offer little insight beyond a flat score-based segmentation from the labeled clinical dataset. To this end, in this paper, we propose a new approach for risk stratification by exploring a large volume of electronic health records (EHRs) in an unsupervised fashion. Along this line, this paper proposes a novel probabilistic topic modeling framework called probabilistic risk stratification model (PRSM) based on Latent Dirichlet Allocation (LDA). The proposed PRSM recognizes a patient clinical state as a probabilistic combination of latent sub-profiles, and generates sub-profile-specific risk tiers of patients from their EHRs in a fully unsupervised fashion. The achieved stratification results can be easily recognized as high-, medium- and low-risk, respectively. In addition, we present an extension of PRSM, called weakly supervised PRSM (WS-PRSM) by incorporating minimum prior information into the model, in order to improve the risk stratification accuracy, and to make our models highly portable to risk stratification tasks of various diseases. We verify the effectiveness of the proposed approach on a clinical dataset containing 3463 coronary heart disease (CHD) patient instances. Both PRSM and WS-PRSM were compared with two established supervised risk stratification algorithms, i.e., logistic regression and support vector machine, and showed the effectiveness of our models in risk stratification of CHD in terms of the Area Under the receiver operating characteristic Curve (AUC) analysis. As well, in comparison with PRSM, WS-PRSM has over 2% performance gain, on the experimental dataset, demonstrating that

Principal stratification in causal inference.

PubMed

Frangakis, Constantine E; Rubin, Donald B

2002-03-01

Many scientific problems require that treatment comparisons be adjusted for posttreatment variables, but the estimands underlying standard methods are not causal effects. To address this deficiency, we propose a general framework for comparing treatments adjusting for posttreatment variables that yields principal effects based on principal stratification. Principal stratification with respect to a posttreatment variable is a cross-classification of subjects defined by the joint potential values of that posttreatment variable tinder each of the treatments being compared. Principal effects are causal effects within a principal stratum. The key property of principal strata is that they are not affected by treatment assignment and therefore can be used just as any pretreatment covariate. such as age category. As a result, the central property of our principal effects is that they are always causal effects and do not suffer from the complications of standard posttreatment-adjusted estimands. We discuss briefly that such principal causal effects are the link between three recent applications with adjustment for posttreatment variables: (i) treatment noncompliance, (ii) missing outcomes (dropout) following treatment noncompliance. and (iii) censoring by death. We then attack the problem of surrogate or biomarker endpoints, where we show, using principal causal effects, that all current definitions of surrogacy, even when perfectly true, do not generally have the desired interpretation as causal effects of treatment on outcome. We go on to forrmulate estimands based on principal stratification and principal causal effects and show their superiority.

Les agressions sexuelles des jeunes ayant une incapacité ou une maladie chronique

PubMed Central

Kaufman, M

2011-01-01

Pour diverses raisons, les enfants et les adolescents ayant une incapacité ou une maladie chronique sont plus vulnérables aux agressions sexuelles. Les dispensateurs de soins, de même que les parents et les éducateurs, doivent se méfier davantage de la possibilité d’agression sexuelle au sein de cette population. Les médecins, tout particulièrement, doivent prôner des politiques pour prévenir ou déceler les agressions dans les hôpitaux, les écoles et autres établissements. Ces politiques incluent le dépistage détaillé et la surveillance étroite des employés et des bénévoles, la présence d’un chaperon aux examens physiques et aux interventions thérapeutiques, la supervision des sorties et une culture qui favorise la vie privée du patient en établissement. De plus, les médecins doivent favoriser la conscience de soi et l’habilitation des patients et leur donner très tôt des conseils préventifs au sujet de la sexualité, de l’habilitation personnelle et des risques d’agression. Le présent document de principes remplace celui que la Société canadienne de pédiatrie a publié en 1997.

Temperature Stratification in a Cryogenic Fuel Tank

NASA Technical Reports Server (NTRS)

Daigle, Matthew John; Smelyanskiy, Vadim; Boschee, Jacob; Foygel, Michael Gregory

2013-01-01

A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It accounts for cryogenic propellant loading, storage, and unloading in the conditions of normal, increased, and micro- gravity. The model involves multiple horizontal control volumes in both liquid and ullage spaces. Temperature and velocity boundary layers at the tank walls are taken into account by using correlation relations. Heat exchange involving the tank wall is considered by means of the lumped-parameter method. By employing basic conservation laws, the model takes into consideration the major multi-phase mass and energy exchange processes involved, such as condensation-evaporation of the hydrogen, as well as flows of hydrogen liquid and vapor in the presence of pressurizing helium gas. The model involves a liquid hydrogen feed line and a tank ullage vent valve for pressure control. The temperature stratification effects are investigated, including in the presence of vent valve oscillations. A simulation of temperature stratification effects in a generic cryogenic tank has been implemented in Matlab and results are presented for various tank conditions.

Drainage and Stratification Kinetics of Foam Films

NASA Astrophysics Data System (ADS)

Zhang, Yiran; Sharma, Vivek

2014-03-01

Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Foam lifetime, drainage kinetics and stability are strongly influenced by surfactant type (ionic vs non-ionic), and added proteins, particles or polymers modify typical responses. The rate at which fluid drains out from a foam film, i.e. drainage kinetics, is determined in the last stages primarily by molecular interactions and capillarity. Interestingly, for certain low molecular weight surfactants, colloids and polyelectrolyte-surfactant mixtures, a layered ordering of molecules, micelles or particles inside the foam films leads to a stepwise thinning phenomena called stratification. Though stratification is observed in many confined systems including foam films containing particles or polyelectrolytes, films containing globular proteins seem not to show this behavior. Using a Scheludko-type cell, we experimentally study the drainage and stratification kinetics of horizontal foam films formed by protein-surfactant mixtures, and carefully determine how the presence of proteins influences the hydrodynamics and thermodynamics of foam films.

Tumeur d'Abrikossoff juxta axillaire: une localisation rare d'une tumeur très rare, à propos d'un cas

PubMed Central

Amourak, Sarah; Bouzoubaa, Wael; Jayi, Sofia; Alaoui, Fatimazahra Fdili; Chaara, Hikmat; Melhouf, Moulay Abdelilah

2015-01-01

Décrite pour la première fois en 1926 par Abrikossoff, les tumeurs à cellules granuleuses (TCG) sont bénignes et uniques dans la grande majorité des cas. Les principales localisations sont la cavité orale, puis les tissus sous-cutanés de la tête et du cou et les seins. La pathogenèse a été longtemps débattue, après avoir proposé initialement une origine musculaire striée les études récentes sont en faveur d'une origine neurogène schwannienne confirmées par une étude immunohistochimique. Le traitement de la tumeur à cellules granuleuses est un traitement chirurgical, il permet un diagnostic de certitude par l'examen anatomo-pathologique de la pièce d'exérèse qui doit rechercher les limites d'exérèse et la présence de critères de malignité. Leur évolution est souvent favorable si la résection chirurgicale est complète. Nous rapportons ici le cas d'une tumeur d'Abrikossoff à localisation juxta axillaire et nous profitons de faire une revue de la littérature afin de mettre le point sur cette entité rare. PMID:26328001

Utility of Risk Stratification for Paclitaxel Hypersensitivity Reactions.

PubMed

Otani, Iris M; Lax, Timothy; Long, Aidan A; Slawski, Benjamin R; Camargo, Carlos A; Banerji, Aleena

2017-10-03

Hypersensitivity reactions (HSRs) are a common impediment to paclitaxel therapy. Management strategies to guide care after a paclitaxel-induced HSR are needed. The objective was to evaluate the utility and safety of risk stratification on the basis of severity of the initial HSR. A risk stratification pathway was developed on the basis of a retrospective review of the management and outcome of 130 patients with paclitaxel-induced HSRs at Massachusetts General Hospital. This pathway was then studied prospectively in patients referred to Allergy/Immunology with paclitaxel-induced HSRs. The study population (n = 35) had a mean age of 56.1 ± 12 years and most were women (n = 33 [94%]). All 5 patients (15%) with grade 1 initial HSRs were successfully reexposed to paclitaxel, 1 patient at the standard infusion rate and 4 patients at 50% of the standard infusion rate. Thirty patients (85%) with grade 2 to 4 initial HSRs underwent initial paclitaxel desensitization based on the risk stratification pathway. No patients developed severe HSRs using the pathway. Eleven (31%) patients had HSRs that were mild to moderate in nature (grade 1, n = 4 [11%]; grade 2, n = 6 [17%]; grade 3, n = 1 [3%]) during their first desensitization. Sixteen (46%) of the 35 patients safely returned to the outpatient infusion setting for paclitaxel treatment at 50% of the standard infusion rate. Seven (20%) discontinued paclitaxel before the completion of the risk stratification pathway because of disease progression, completion of therapy, or death. A management strategy using the initial HSR severity for risk stratification allowed patients to receive paclitaxel safely. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Thrombophlébite cérébrale inhabituelle du post-partum

PubMed Central

El Hassani, Moulay Elmehdi; Habib, Abdellah Baba; Kouach, Jaouad; Sekkach, Youssef; Bakkali, Hicham; Jira, Mohamed; Elqatni, Mohamed; Abouzahir, Ali; Ghafir, Dris; Moussaoui, Dris; Dehayni, Mohamed

2014-01-01

La thrombophlébite cérébrale du post-partum immédiat constitue un événement rare et gravissime pouvant mettre en jeu le pronostic vital à court terme. Celle-ci doit être systématiquement évoquée devant la persistance d'une fièvre dans les suites de couches. La prise en charge associera le plus souvent, des antibiotiques à large spectre et des anticoagulants. Le suivi évolutif est indispensable, afin d'apprécier l'efficacité thérapeutique. A travers une observation singulière et à présentation inhabituelle, nous insistons sur le grand intérêt des moyens d'imagerie dont nous disposons afin de porter le diagnostic et de choisir le traitement le mieux adapté. PMID:25478039

Eddy-driven stratification initiates North Atlantic spring phytoplankton blooms.

PubMed

Mahadevan, Amala; D'Asaro, Eric; Lee, Craig; Perry, Mary Jane

2012-07-06

Springtime phytoplankton blooms photosynthetically fix carbon and export it from the surface ocean at globally important rates. These blooms are triggered by increased light exposure of the phytoplankton due to both seasonal light increase and the development of a near-surface vertical density gradient (stratification) that inhibits vertical mixing of the phytoplankton. Classically and in current climate models, that stratification is ascribed to a springtime warming of the sea surface. Here, using observations from the subpolar North Atlantic and a three-dimensional biophysical model, we show that the initial stratification and resulting bloom are instead caused by eddy-driven slumping of the basin-scale north-south density gradient, resulting in a patchy bloom beginning 20 to 30 days earlier than would occur by warming.

Breakup of last glacial deep stratification in the South Pacific.

PubMed

Basak, Chandranath; Fröllje, Henning; Lamy, Frank; Gersonde, Rainer; Benz, Verena; Anderson, Robert F; Molina-Kescher, Mario; Pahnke, Katharina

2018-02-23

Stratification of the deep Southern Ocean during the Last Glacial Maximum is thought to have facilitated carbon storage and subsequent release during the deglaciation as stratification broke down, contributing to atmospheric CO 2 rise. Here, we present neodymium isotope evidence from deep to abyssal waters in the South Pacific that confirms stratification of the deepwater column during the Last Glacial Maximum. The results indicate a glacial northward expansion of Ross Sea Bottom Water and a Southern Hemisphere climate trigger for the deglacial breakup of deep stratification. It highlights the important role of abyssal waters in sustaining a deep glacial carbon reservoir and Southern Hemisphere climate change as a prerequisite for the destabilization of the water column and hence the deglacial release of sequestered CO 2 through upwelling. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

The Effect of Barotropic and Baroclinic Tides on Coastal Stratification and Mixing

NASA Astrophysics Data System (ADS)

Suanda, S. H.; Feddersen, F.; Kumar, N.

2017-12-01

The effects of barotropic and baroclinic tides on subtidal stratification and vertical mixing are examined with high-resolution, three-dimensional numerical simulations of the Central Californian coastal upwelling region. A base simulation with realistic atmospheric and regional-scale boundary forcing but no tides (NT) is compared to two simulations with the addition of predominantly barotropic local tides (LT) and with combined barotropic and remotely generated, baroclinic tides (WT) with ≈ 100 W m-1 onshore baroclinic energy flux. During a 10 day period of coastal upwelling when the domain volume-averaged temperature is similar in all three simulations, LT has little difference in subtidal temperature and stratification compared to NT. In contrast, the addition of remote baroclinic tides (WT) reduces the subtidal continental shelf stratification up to 50% relative to NT. Idealized simulations to isolate barotropic and baroclinic effects demonstrate that within a parameter space of typical U.S. West Coast continental shelf slopes, barotropic tidal currents, incident energy flux, and subtidal stratification, the dissipating baroclinic tide destroys stratification an order of magnitude faster than barotropic tides. In WT, the modeled vertical temperature diffusivity at the top (base) of the bottom (surface) boundary layer is increased up to 20 times relative to NT. Therefore, the width of the inner-shelf (region of surface and bottom boundary layer overlap) is increased approximately 4 times relative to NT. The change in stratification due to dissipating baroclinic tides is comparable to the magnitude of the observed seasonal cycle of stratification.

Revealing the timing of ocean stratification using remotely-sensed ocean fronts: links with marine predators

NASA Astrophysics Data System (ADS)

Miller, P. I.; Loveday, B. R.

2016-02-01

Stratification is of critical importance to the mixing and productivity of the ocean, though currently it can only be measured using in situ sampling, profiling buoys or underwater autonomous vehicles. Stratification is understood to affect the surface aggregation of pelagic fish and hence the foraging behaviour and distribution of their predators such as seabirds and cetaceans. Satellite Earth observation sensors cannot directly detect stratification, but can observe surface features related to the presence of stratification, for example shelf-sea fronts that separate tidally-mixed water from seasonally stratified water. This presentation describes a novel algorithm that accumulates evidence for stratification from a sequence of oceanic front maps, and in certain regions can reveal the timing of the seasonal onset and breakdown of stratification. Initial comparisons will be made with seabird locations acquired through GPS tagging. If successful, a remotely-sensed stratification timing index would augment the ocean front metrics already developed at PML, that have been applied in over 20 journal articles relating marine predators to ocean fronts. The figure below shows a preliminary remotely-sensed 'stratification' index, for 25-31 Jul. 2010, where red indicates water with stronger evidence for stratification.

Néphrocalcinose compliquant une miliaire tuberculeuse chez un nourrisson

PubMed Central

El Maghraoui, Jaouad; Souilmi, Fatima Zahrae; Hbibi, Mohamed; Houssaini, Tarik Sqalli; Hida, Mustapha

2015-01-01

La néphrocalcinose se définit par la présence anormale dans le parenchyme rénal de dépôts calciques pouvant résulter de différentes affections. Nous rapportons le cas d'un nourrisson de 7 mois chez qui nous avons diagnostiqué une hypercalcémie compliquée par une néphrocalcinose secondaire à une tuberculose miliaire aggravée par l'intoxication à la vitamine D améliorée sous hyperhydratation, furosémide et glucocorticoïdes. A travers ce travail, nous insistons sur l'intérêt de la recherche d'une hypercalcémie devant toute infection tuberculeuse, de la prise en charge rapide et adaptée sans oublié d'interrompre la supplémentation en vitamine D. PMID:26309458

Areal Control Using Generalized Least Squares As An Alternative to Stratification

Treesearch

Raymond L. Czaplewski

2001-01-01

Stratification for both variance reduction and areal control proliferates the number of strata, which causes small sample sizes in many strata. This might compromise statistical efficiency. Generalized least squares can, in principle, replace stratification for areal control.

L’alimentation des enfants ayant une déficience neurologique

PubMed Central

2009-01-01

La malnutrition, qu’il s’agisse de sous-alimentation ou de suralimentation, est courante chez les enfants ayant une déficience neurologique. Les besoins en énergie sont difficiles à définir au sein de cette population hétérogène. De plus, on manque d’information sur ce qui constitue la croissance normale chez ces enfants. Des facteurs non nutritionnels peuvent influer sur la croissance, mais des facteurs nutritionnels, tels qu’un apport calorique insuffisant, des pertes excessives d’éléments nutritifs et un métabolisme énergétique anormal, contribuent également au retard de croissance de ces enfants. La malnutrition est liée à une importante morbidité, tandis que la réadaptation nutritionnelle améliore l’état de santé global. Le soutien nutritionnel doit faire partie intégrante de la prise en charge des enfants ayant une déficience nutritionnelle et viser non seulement à améliorer l’état nutritionnel, mais également la qualité de vie des patients et de leur famille. Au moment d’envisager une intervention nutritionnelle, il faut tenir compte du dysfonctionnement oromoteur, du reflux gastro-œsophagien et de l’aspiration pulmonaire, et une équipe multidisciplinaire doit se concerter. Il faut repérer rapidement les enfants vulnérables à des troubles nutritionnels et procéder à une évaluation de leur état nutritionnel au moins une fois par année, et plus souvent chez les nourrissons et les jeunes enfants ou chez les enfants qui risquent de souffrir de malnutrition. Il faut optimiser l’apport oral s’il est sécuritaire, mais entreprendre une alimentation entérale chez les enfants ayant un dysfonctionnement oromoteur qui provoque une aspiration marquée ou chez ceux qui sont incapables de maintenir un état nutritionnel suffisant au moyen de l’apport oral. Il faut réserver l’alimentation par sonde nasogastrique aux interventions à court terme, mais si une intervention nutritionnelle prolongée s�

Molecular reclassification of Crohn's disease: a cautionary note on population stratification.

PubMed

Maus, Bärbel; Jung, Camille; Mahachie John, Jestinah M; Hugot, Jean-Pierre; Génin, Emmanuelle; Van Steen, Kristel

2013-01-01

Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn's disease (CD) patients are heterogeneous with regard to disease location and disease extent. The genetic susceptibility to Crohn's disease is widely acknowledged and has been demonstrated by identification of over 100 CD associated genetic loci. However, relating CD subphenotypes to disease susceptible loci has proven to be a difficult task. In this paper we discuss the use of cluster analysis on genetic markers to identify genetic-based subgroups while taking into account possible confounding by population stratification. We show that it is highly relevant to consider the confounding nature of population stratification in order to avoid that detected clusters are strongly related to population groups instead of disease-specific groups. Therefore, we explain the use of principal components to correct for population stratification while clustering affected individuals into genetic-based subgroups. The principal components are obtained using 30 ancestry informative markers (AIM), and the first two PCs are determined to discriminate between continental origins of the affected individuals. Genotypes on 51 CD associated single nucleotide polymorphisms (SNPs) are used to perform latent class analysis, hierarchical and Partitioning Around Medoids (PAM) cluster analysis within a sample of affected individuals with and without the use of principal components to adjust for population stratification. It is seen that without correction for population stratification clusters seem to be influenced by population stratification while with correction clusters are unrelated to continental origin of individuals.

Buried layers: On the origins, rise, and fall of stratification theories.

PubMed

Wieser, Martin

2018-02-01

This article presents a historical analysis of the origins, rise, and demise of theories of stratification ( Schichtentheorien ). Following their roots in the ancient metaphysical idea of the "great chain of being," Aristotle's scala naturae , the medieval "Jacob's ladder," and Leibniz's concept of the lex continua, I argue that theories of stratification represent the modern heir to the ancient cosmological idea of a harmonious, hierarchical, and unified universe. Theories of stratification reached their heyday during the interwar period within German academia, proliferating over a vast number of disciplines and rising to special prominence within personality psychology, feeding the hope for a unitary image of the world and of human beings, their biological and mental development, their social organization and cultural creations. This article focuses on the role of visuality as a distinct mode of scientific knowledge within theories of stratification as well as the cultural context that provided the fertile ground for their flowering in the Weimar Republic. Finally, the rapid demise of theories of stratification during the 1950s is discussed, and some reasons for their downfall during the second half of the 20th century are explored. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Cardiac risk stratification in cardiac rehabilitation programs: a review of protocols

PubMed Central

da Silva, Anne Kastelianne França; Barbosa, Marianne Penachini da Costa de Rezende; Bernardo, Aline Fernanda Barbosa; Vanderlei, Franciele Marques; Pacagnelli, Francis Lopes; Vanderlei, Luiz Carlos Marques

2014-01-01

Objective Gather and describe general characteristics of different protocols of risk stratification for cardiac patients undergoing exercise. Methods We conducted searches in LILACS, IBECS, MEDLINE, Cochrane Library, and SciELO electronic databases, using the following descriptors: Cardiovascular Disease, Rehabilitation Centers, Practice Guideline, Exercise and Risk Stratification in the past 20 years. Results Were selected eight studies addressing methods of risk stratification in patients undergoing exercise. Conclusion None of the methods described could cover every situation the patient can be subjected to; however, they are essential to exercise prescription. PMID:25140477

Comments: Should Principal Stratification Be Used to Study Mediational Processes?

ERIC Educational Resources Information Center

VanderWeele, Tyler J.

2012-01-01

Principal stratification provides an approach to study the effect of an exposure on an outcome within strata defined by the effect of the exposure on some third, posttreatment, variable (Frangakis & Rubin, 2002). There has been more recent interest in using principal stratification to study the extent to which the effect of an exposure on an…

Change and Stability in Educational Stratification.

ERIC Educational Resources Information Center

Mare, Robert D.

1981-01-01

Using statistical models, discusses educational stratification with respect to socioeconomic origins. Describes the effects of social background on grade progression change across cohorts born during the 20th century and the consequences of these changes. (JW)

Orderedness and Stratificational "and" Nodes.

ERIC Educational Resources Information Center

Herrick, Earl M.

It is possible to apply Lamb's stratificational theory and analysis to English graphonomy, but additional notation devices must be used to explain particular graphemes and their characteristics. The author presents cases where Lamb's notation is inadequate. In those cases, he devises new means for performing the analysis. The result of this…

How-to-Do-It: A Practical Method for Teaching Seed Stratification.

ERIC Educational Resources Information Center

Englert, Karen M.; Shontz, Nancy N.

1989-01-01

Described is a laboratory procedure for teaching seed stratification. Materials, methods, results, and applicability of the experiment are explained. Diagrams showing the percent of total germination as a function of stratification time and the germination rate of stratified seeds are included. (RT)

The bio-optical properties of CDOM as descriptor of lake stratification.

PubMed

Bracchini, Luca; Dattilo, Arduino Massimo; Hull, Vincent; Loiselle, Steven Arthur; Martini, Silvia; Rossi, Claudio; Santinelli, Chiara; Seritti, Alfredo

2006-11-01

Multivariate statistical techniques are used to demonstrate the fundamental role of CDOM optical properties in the description of water masses during the summer stratification of a deep lake. PC1 was linked with dissolved species and PC2 with suspended particles. In the first principal component that the role of CDOM bio-optical properties give a better description of the stratification of the Salto Lake with respect to temperature. The proposed multivariate approach can be used for the analysis of different stratified aquatic ecosystems in relation to interaction between bio-optical properties and stratification of the water body.

Thermal stratification potential in rocket engine coolant channels

NASA Technical Reports Server (NTRS)

Kacynski, Kenneth J.

1992-01-01

The potential for rocket engine coolant channel flow stratification was computationally studied. A conjugate, 3-D, conduction/advection analysis code (SINDA/FLUINT) was used. Core fluid temperatures were predicted to vary by over 360 K across the coolant channel, at the throat section, indicating that the conventional assumption of a fully mixed fluid may be extremely inaccurate. Because of the thermal stratification of the fluid, the walls exposed to the rocket engine exhaust gases will be hotter than an assumption of full mixing would imply. In this analysis, wall temperatures were 160 K hotter in the turbulent mixing case than in the full mixing case. The discrepancy between the full mixing and turbulent mixing analyses increased with increasing heat transfer. Both analysis methods predicted identical channel resistances at the coolant inlet, but in the stratified analysis the thermal resistance was negligible. The implications are significant. Neglect of thermal stratification could lead to underpredictions in nozzle wall temperatures. Even worse, testing at subscale conditions may be inadequate for modeling conditions that would exist in a full scale engine.

High resolution monitoring of episodic stratification events in an enclosed marine system

NASA Astrophysics Data System (ADS)

Sullivan, Timothy; Broszeit, Stefanie; O'Sullivan, Keith P. A.; McAllen, Rob; Davenport, John; Regan, Fiona

2013-05-01

While hypoxic and anoxic environments have existed throughout geological time, their frequency of occurrence in shallow coastal and estuarine areas appears to be increasing. However, few data are available on the physicochemical conditions at the boundary between anoxic and normoxic layers, including the conditions required for both formation and dissipation of stratification. Advances in autonomous environmental sensing technology have produced robust sensors capable of detailed measurements under inhospitable conditions created in such environments. In this study, an autonomous sensor approach was used to compare water column properties above and below the stratification before during and after dissipation of the stratification. Further, an investigation into the effect of the stratification on sedimentation rates of organic and inorganic matter and current speeds is reported here. Lough Hyne, a seasonally stratified temperate marine lake provided favourable conditions for this study. It was shown that temperatures dropped rapidly above the oxy-thermocline while increasing rapidly below the stratification, leading to a mixing of the complete water column. This was reflected in oxygen measurements below the stratification, which rose from anoxia to normoxic conditions over the same time period. During summer, the thermocline formed a barrier to organic matter sedimentation, reducing it significantly when present, while inorganic matter sedimentation was unaffected by the presence of thermocline. It also caused a reduction in current speeds below the thermocline.

Torsion d'annexe au second trimestre de la grossesse, à propos de deux cas

PubMed Central

Ayachi, Amira; Blel, Zeineb; Khelifa, Nahed; Mkaouer, Lassaad; Bouchahda, Rim; Mourali, Mechaal

2016-01-01

Les douleurs pelviennes aigues pendant la grossesse peuvent poser un problème de diagnostic différentiel.Nous rapportons deux cas de torsion d'annexes au deuxième trimestre de la grossesse afin d'attirer l'attention sur ce diagnostic, dont seule une prise en charge précoce permet d'éviter des lésions irréversibles dues à l'ischémie, pouvant mettre en jeu le pronostic ultérieur de fertilité. La première patiente, G1P0, enceinte à 20 SA, s'est présenté initialement pour un syndrome appendiculaire. Une incision de Mac Burney, au cours de l'exploration, a montré un ovaire droit nécrosé et une ovariectomie a été faite. Les suites post opératoires étaient simples. La seconde patiente, G2P2, s'est présenté aux urgences avec des douleurs aigues de la fosse iliaque gauche à 26 SA. La laparotomie a mis en évidence une torsion d'une hydatide de Morgani, dont l'aspect nécrosé dû à une torsion, a orienté vers une ablation de l'hydatide. Pour les deux patientes, aucune complication postopératoire n'a été relevée. La torsion d'annexe est une urgence à ne pas méconnaître devant toute douleur pelvienne aigue chez la femme enceinte. Le traitement conservateur est actuellement le gold standard et une prise en charge appropriée est nécessaire pour éviter d'éventuelles complications maternelles et fœtales. PMID:28292076

Abundance stratification in the atmospheres of blue horizontal-branch stars

NASA Astrophysics Data System (ADS)

LeBlanc, F.

2013-12-01

Horizontal-branch stars with effective temperatures larger than approximately 11 500 K show abundance anomalies as well as other peculiar observational properties believed to be due to atomic diffusion in their atmosphere. These stars possess low rotational velocities that makes it possible for atomic diffusion to come into play and are therefore of great interest with respect to diffusion theory. Observational anomalies of blue horizontal-branch stars found in globular clusters such as photometric jumps and gaps are reviewed. Recent detections of vertical stratification of elements are also discussed. These results are compared to predictions of atmospheric modeling while including vertical stratification of the elements. The atmospheric structure of these models is calculated self-consistently while taking into account vertical stratification of the elements.

Contrasting Drainage and Stratification in Horizontal Vs Vertical Micellar Foam Films

NASA Astrophysics Data System (ADS)

Wojcik, Ewelina; Yilixiati, Subinuer; Zhang, Yiran; Sharma, Vivek

Understanding and controlling the drainage kinetics of thin films is an important problem that underlies the stability, lifetime and rheology of foams and emulsions. In foam films formed with micellar solutions, the surfactant is present as interfacially-adsorbed layer at both liquid-air interfaces, as well as in bulk as self-assembled supramolecular structures called micelles. Ultrathin micellar films exhibit stratification due to confinement-induced structuring and layering of micelles. Stratification in micellar foam films is manifested as stepwise thinning over time, and it leads to the coexistence of flat domains with discretely different thicknesses. In this contribution we use Interferometry Digital Imaging Optical Microscopy (IDIOM) protocols to visualize and analyze thickness transitions and variations associated with stratification in micellar foam films made with sodium dodecyl sulfate (SDS). We contrast the drainage and stratification dynamics in horizontal and vertical foam films, and investigate the role played by gravitational, viscous, interfacial and surface forces.

On Stratification in Changing Higher Education: The "Analysis of Status" Revisited

ERIC Educational Resources Information Center

Bloch, Roland; Mitterle, Alexander

2017-01-01

This article seeks to shed light on current dynamics of stratification in changing higher education and proposes an analytical perspective to account for these dynamics based on Martin Trow's work on "the analysis of status." In research on higher education, the term "stratification" is generally understood as a metaphor that…

Molecular Reclassification of Crohn’s Disease: A Cautionary Note on Population Stratification

PubMed Central

Maus, Bärbel; Jung, Camille; Mahachie John, Jestinah M.; Hugot, Jean-Pierre; Génin, Emmanuelle; Van Steen, Kristel

2013-01-01

Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn’s disease (CD) patients are heterogeneous with regard to disease location and disease extent. The genetic susceptibility to Crohn’s disease is widely acknowledged and has been demonstrated by identification of over 100 CD associated genetic loci. However, relating CD subphenotypes to disease susceptible loci has proven to be a difficult task. In this paper we discuss the use of cluster analysis on genetic markers to identify genetic-based subgroups while taking into account possible confounding by population stratification. We show that it is highly relevant to consider the confounding nature of population stratification in order to avoid that detected clusters are strongly related to population groups instead of disease-specific groups. Therefore, we explain the use of principal components to correct for population stratification while clustering affected individuals into genetic-based subgroups. The principal components are obtained using 30 ancestry informative markers (AIM), and the first two PCs are determined to discriminate between continental origins of the affected individuals. Genotypes on 51 CD associated single nucleotide polymorphisms (SNPs) are used to perform latent class analysis, hierarchical and Partitioning Around Medoids (PAM) cluster analysis within a sample of affected individuals with and without the use of principal components to adjust for population stratification. It is seen that without correction for population stratification clusters seem to be influenced by population stratification while with correction clusters are unrelated to continental origin of individuals. PMID:24147066

Pseudotumeur cardiaque révélant une maladie de Behçet

PubMed Central

Nya, Fouad; Abdou, Abdessamad; Bamous, Mehdi; Moutakiallah, Younes; Atmani, Noureddine; Seghrouchni, Aniss; Houssa, Mahdi Ait; Boulahya, Abdellatif

2017-01-01

La thrombose intracardiaque est une complication rare de la maladie de Behçet (MB), qui peut se présenter comme une tumeur intracardiaque. Sa découverte précède, dans la moitié des cas, le diagnostic de MB. La mortalité élevée peut être en rapport avec des complications post-chirurgicales et/ou une atteinte associée des artères pulmonaires. Nous rapportons l’observation d’un jeune patient de 29 ans, aux antécédents d’aphtose bipolaire, qui a bénéficie d’une intervention chirurgicale après la découverte d’une tumeur de l’atrium et du ventricule droits. Il s’agissait d’un thrombus à l’examen anatomopathologique et dans les suites opératoires nous avons diagnostiqué une MB. L’évolution a été favorable sous traitement médical associant une corticothérapie, de la colchicine et des antivitamines K (AVK). La découverte d’une masse intracardiaque chez un sujet jeune doit faire évoquer le diagnostic de thrombus cardiaque et de maladie de Behçet, même en l’absence de facteur ethnique ou géographique prédisposant. PMID:28533874

Curriculum Placement and Educational Stratification in France.

ERIC Educational Resources Information Center

Hout, Michael; Garnier, Maurice A.

1979-01-01

Maintains that curriculum differentiation in France is the keystone of educational, and, consequently, social stratification. Factors which influence curriculum differentiation include father's occupation, academic performance, parents' expectations, and teachers' expectations. (DB)

Propagation of 3D internal gravity wave beams in a slowly varying stratification

NASA Astrophysics Data System (ADS)

Fan, Boyu; Akylas, T. R.

2017-11-01

The time-mean flows induced by internal gravity wave beams (IGWB) with 3D variations have been shown to have dramatic implications for long-term IGWB dynamics. While uniform stratifications are convenient both theoretically and in the laboratory, stratifications in the ocean can vary by more than an order of magnitude over the ocean depth. Here, in view of this fact, we study the propagation of a 3D IGWB in a slowly varying stratification. We assume that the stratification varies slowly relative to the local variations in the wave profile. In the 2D case, the IGWB bends in response to the changing stratification, but nonlinear effects are minor even in the finite amplitude regime. For a 3D IGWB, in addition to bending, we find that nonlinearity results in the transfer of energy from waves to a large-scale time-mean flow associated with the mean potential vorticity, similar to IGWB behavior in a uniform stratification. In a weakly nonlinear setting, we derive coupled evolution equations that govern this process. We also use these equations to determine the stability properties of 2D IGWB to 3D perturbations. These findings indicate that 3D effects may be relevant and possibly fundamental to IGWB dynamics in nature. Supported by NSF Grant DMS-1512925.

Syndrome coronarien aigue suite à une injection accidentelle intraveineuse de Bupivacaine

PubMed Central

Koita, Siriman Abdoulaye; Bouhabba, Najib; Salaheddine, Fjouji; Bensghir, Mustapha; Charki, Haimeur

2015-01-01

Les erreurs médicamenteuses constituent une complication très redoutable en anesthésie. La fréquence des erreurs médicamenteuses par administration serait de l'ordre 1/10 000 à 1/1000. Nous rapportons un cas d'injection accidentelle de bupivacaine en intraveineuse directe. Il s'agissait d'un jeune patient classé ASA I qui était prévu pour cure chirurgicale d'une hydrocèle unilatérale sous rachianesthésie. Une injection de 12,5 mg de bupivacaine et 25 µg de fentanyl étaient injectés après un reflux net du liquide céphalorachidien sans incident. Après installation de la rachianesthésie, le début de l'intervention était autorisé sans incidents. Une sédation de confort était décidée. Juste après apparaissait des troubles de rythme à type tachycardie ventriculaire avec une élévation de taux de troponines en post opératoire. L’évolution était marquée par une normalisation de la troponine au troisième jour post opératoire et sorti de l'hôpital au cinquième jour. PMID:26889325

Le kyste hydatique du cordon spermatique: une localisation exceptionnelle

PubMed Central

Hamdane, Mohamed Moncef; Bougrine, Fethi; Msakni, Issam; Dhaoui-Ghozzi, Amen; Bouziani, Ammar

2011-01-01

L’ hydatidose est une anthropo-zoonose due au développement chez l'homme de la forme larvaire du taenia Echinococcus granulosis. La plupart des kystes hydatiques se localisent dans le foie et les poumons. Le kyste hydatique du cordon spermatique est extrêmement rare avec seulement 4 cas rapportés dans la littérature. Les auteurs rapportent dans cet article un nouveau cas d'hydatidose du cordon spermatique. Il s'agissait d'un homme de 40 ans qui consultait pour des douleurs scrotales évoluant depuis huit mois. L'examen clinique a mis en évidence une tuméfaction mobile, inguino-scrotale, droite. L’échographie testiculaire a objectivé une hernie inguinale droite associée à deux kystes épididymaires bilatéraux. Le patient a été opéré pour cure de son hernie avec découverte en per-opératoire d'un kyste du cordon spermatique qui a été réséqué. L'examen anatomopathologique a conclu à une hydatidose du cordon spermatique. PMID:22384304

An Improved Model of Cryogenic Propellant Stratification in a Rotating, Reduced Gravity Environment

NASA Technical Reports Server (NTRS)

Oliveira, Justin; Kirk, Daniel R.; Schallhorn, Paul A.; Piquero, Jorge L.; Campbell, Mike; Chase, Sukhdeep

2007-01-01

This paper builds on a series of analytical literature models used to predict thermal stratification within rocket propellant tanks. The primary contribution to the literature is to add the effect of tank rotation and to demonstrate the influence of rotation on stratification times and temperatures. This work also looks levels of thermal stratification for generic propellant tanks (cylindrical shapes) over a parametric range of upper-stage coast times, heating levels, rotation rates, and gravity levels.

Glacial/interglacial changes in subarctic north pacific stratification.

PubMed

Jaccard, S L; Haug, G H; Sigman, D M; Pedersen, T F; Thierstein, H R; Röhl, U

2005-05-13

Since the first evidence of low algal productivity during ice ages in the Antarctic Zone of the Southern Ocean was discovered, there has been debate as to whether it was associated with increased polar ocean stratification or with sea-ice cover, shortening the productive season. The sediment concentration of biogenic barium at Ocean Drilling Program site 882 indicates low algal productivity during ice ages in the Subarctic North Pacific as well. Site 882 is located southeast of the summer sea-ice extent even during glacial maxima, ruling out sea-ice-driven light limitation and supporting stratification as the explanation, with implications for the glacial cycles of atmospheric carbon dioxide concentration.

Cause rare d'une perforation de la cloison nasale

PubMed Central

Jahidi, Ali; Hemmaoui, Bouchaïb; Itoua, Wulfran Rosaire; Errami, Noureddine; Benariba, Fouad

2014-01-01

Les perforations de la cloison nasale constituent une pathologie fréquente en ORL. Leurs causes sont multiples et restent dominées par les traumatismes chirurgicaux. Les étiologies infectieuses et notamment la tuberculose sont rares. Nous présentons le cas d'une patiente ayant bénéficié d'une méatotomie bilatérale et chez laquelle une perforation de la cloison nasale a été découverte lors d'un examen systématique à un an de son intervention. D'abord considérée comme une complication de la chirurgie, la biopsie des berges de la perforation a permis de déterminer son origine tuberculeuse. La présentation clinique des perforations de la cloison nasale n'est pas spécifique. Elles sont souvent asymptomatiques et de découverte fortuite. Les traumatismes notamment chirurgicaux sont le plus siuvent en cause. L′orogine tuberculeuse resta très rare. Le diagnostic de certitude de tuberculose repose sur la biopsie des berges de cette perforation. Le but de ce travail est de mettre en avant l'intérêt de la biopsie dans le diagnostic de la tuberculose de la cloison nasale. Cette biopsie doit être systématique même en cas d'antécédents de chirurgie endonasale qui est le plus souvent en cause dans les perforations de la cloison nasale. PMID:24932334

Stratification of a closed region containing two buoyancy sources

NASA Astrophysics Data System (ADS)

Thompson, Andrew; Linden, Paul

2005-11-01

Many closed systems such as lakes, ocean basins, rooms etc. have inputs of buoyancy at different levels. We address the question of how the resulting stratification depends on the location of these sources. For example a lake is heated and cooled at the surface, while for a room cool air may be applied at the ceiling but the heat source may be a person standing on the floor. We present an experimental study of convection in a finite box in which we systematically vary the vertical location of two well-separated, constant buoyancy sources. We specifically consider the case of a dense source and a light source so that there is no net buoyancy flux into the tank. We study the development of the large-time stratification in the tank, which falls between one of two limits. When the location of the dense source is significantly higher than the light source, the fluid is well mixed and the system remains largely unstratified. When the location of the light source is significantly higher than the dense source, a two- layer stratification develops. We find that the circulation pattern is dominated by counter-flowing shear layers (Wong, Griffiths & Hughes, 2001), whose number and strength are strongly influenced by the buoyancy source locations. The shear layers are the primary means of communication between the plumes and thus play a large role in the resulting stratification. We support our findings with a simple numerical model.

Diurnal and Seasonal Variations of Thermal Stratification and Vertical Mixing in a Shallow Fresh Water Lake

NASA Astrophysics Data System (ADS)

Yang, Yichen; Wang, Yongwei; Zhang, Zhen; Wang, Wei; Ren, Xia; Gao, Yaqi; Liu, Shoudong; Lee, Xuhui

2018-04-01

Among several influential factors, the geographical position and depth of a lake determine its thermal structure. In temperate zones, shallow lakes show significant differences in thermal stratification compared to deep lakes. Here, the variation in thermal stratification in Lake Taihu, a shallow fresh water lake, is studied systematically. Lake Taihu is a warm polymictic lake whose thermal stratification varies in short cycles of one day to a few days. The thermal stratification in Lake Taihu has shallow depths in the upper region and a large amplitude in the temperature gradient, the maximum of which exceeds 5°C m-1. The water temperature in the entire layer changes in a relatively consistent manner. Therefore, compared to a deep lake at similar latitude, the thermal stratification in Lake Taihu exhibits small seasonal differences, but the wide variation in the short term becomes important. Shallow polymictic lakes share the characteristic of diurnal mixing. Prominent differences on the duration and frequency of long-lasting thermal stratification are found in these lakes, which may result from the differences of local climate, lake depth, and fetch. A prominent response of thermal stratification to weather conditions is found, being controlled by the stratifying effect of solar radiation and the mixing effect of wind disturbance. Other than the diurnal stratification and convection, the representative responses of thermal stratification to these two factors with contrary effects are also discussed. When solar radiation increases, stronger wind is required to prevent the lake from becoming stratified. A daily average wind speed greater than 6 m s-1 can maintain the mixed state in Lake Taihu. Moreover, wind-induced convection is detected during thermal stratification. Due to lack of solar radiation, convection occurs more easily in nighttime than in daytime. Convection occurs frequently in fall and winter, whereas long-lasting and stable stratification causes

Glacial ocean circulation and stratification explained by reduced atmospheric temperature.

PubMed

Jansen, Malte F

2017-01-03

Earth's climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5-10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage.

Correction of Population Stratification in Large Multi-Ethnic Association Studies

PubMed Central

Serre, David; Montpetit, Alexandre; Paré, Guillaume; Engert, James C.; Yusuf, Salim; Keavney, Bernard; Hudson, Thomas J.; Anand, Sonia

2008-01-01

Background The vast majority of genetic risk factors for complex diseases have, taken individually, a small effect on the end phenotype. Population-based association studies therefore need very large sample sizes to detect significant differences between affected and non-affected individuals. Including thousands of affected individuals in a study requires recruitment in numerous centers, possibly from different geographic regions. Unfortunately such a recruitment strategy is likely to complicate the study design and to generate concerns regarding population stratification. Methodology/Principal Findings We analyzed 9,751 individuals representing three main ethnic groups - Europeans, Arabs and South Asians - that had been enrolled from 154 centers involving 52 countries for a global case/control study of acute myocardial infarction. All individuals were genotyped at 103 candidate genes using 1,536 SNPs selected with a tagging strategy that captures most of the genetic diversity in different populations. We show that relying solely on self-reported ethnicity is not sufficient to exclude population stratification and we present additional methods to identify and correct for stratification. Conclusions/Significance Our results highlight the importance of carefully addressing population stratification and of carefully “cleaning” the sample prior to analyses to obtain stronger signals of association and to avoid spurious results. PMID:18196181

Electrodiagnosis of ulnar neuropathy at the elbow (Une): a Bayesian approach.

PubMed

Logigian, Eric L; Villanueva, Raissa; Twydell, Paul T; Myers, Bennett; Downs, Marlene; Preston, David C; Kothari, Milind J; Herrmann, David N

2014-03-01

In ulnar neuropathy at the elbow (UNE), we determined how electrodiagnostic cutoffs [across-elbow ulnar motor conduction velocity slowing (AECV-slowing), drop in across-elbow vs. forearm CV (AECV-drop)] depend on pretest probability (PreTP). Fifty clinically defined UNE patients and 50 controls underwent ulnar conduction testing recording abductor digiti minimi (ADM) and first dorsal interosseous (FDI), stimulating wrist, below-elbow, and 6-, 8-, and 10-cm more proximally. For various PreTPs of UNE, the cutoffs required to confirm UNE (defined as posttest probability = 95%) were determined with receiver operator characteristic (ROC) curves and Bayes Theorem. On ROC and Bayesian analyses, the ADM 10-cm montage was optimal. For PreTP = 0.25, the confirmatory cutoffs were >23 m/s (AECV-drop), and <38 m/s (AECV-slowing); for PreTP = 0.75, they were much less conservative: >14 m/s, and <47 m/s, respectively. (1) In UNE, electrodiagnostic cutoffs are critically dependent on PreTP; rigid cutoffs are problematic. (2) AE distances should be standardized and at least 10 cm. Copyright © 2013 Wiley Periodicals, Inc.

Marginal Mean Weighting through Stratification: Adjustment for Selection Bias in Multilevel Data

ERIC Educational Resources Information Center

Hong, Guanglei

2010-01-01

Defining causal effects as comparisons between marginal population means, this article introduces marginal mean weighting through stratification (MMW-S) to adjust for selection bias in multilevel educational data. The article formally shows the inherent connections among the MMW-S method, propensity score stratification, and…

Analyse experimentale des performances d'une batterie au lithium pour l'aeronautique

NASA Astrophysics Data System (ADS)

Bonnin, Romain

Ce memoire a pour objectif d'identifier et d'etudier les performances necessaires pour qu'une batterie au lithium puisse etre utilisee dans le secteur de l'aeronautique. C'est pourquoi dans le cadre de notre recherche, nous allons proposer une procedure de tests permettant d'analyser et de determiner si la batterie au lithium peut etre implantee dans un avion. En vue de repondre a l'analyse des performances, une etude des fonctionnalites demandees par l'avion ainsi que des normes preexistantes vont etre effectuees. Suite a cette etape, nous allons elaborer un banc d'essais. Une fois le banc d'essais acheve, nous allons tester une batterie au lithium qui est supposee disposer de toutes les caracteristiques techniques requises pour etre implantee dans un avion. Ces tests nous permettront donc d'emettre un avis sur l'utilisation des batteries au lithium dans le domaine de l'aeronautique.

Rainfall as a trigger for stratification and winter phytoplankton growth in temperate shelf seas

NASA Astrophysics Data System (ADS)

Jardine, Jenny; Palmer, Matthew; Mahaffey, Claire; Holt, Jason; Mellor, Adam; Wakelin, Sarah

2017-04-01

We present new data from ocean gliders to investigate physical controls on stratification and phytoplankton dynamics, collected in the Celtic Sea between November 2014 and August 2015 as part of the UK Shelf Sea Biogeochemistry programme. This presentation focuses on the winter period (Jan-March) when the diurnal heating cycle results in regular but weak near surface stratification followed by night-time convection. Despite low light conditions, this daily cycle often promotes a daytime increase in observed chlorophyll fluorescence, indicative of phytoplankton growth. This daily cycle is occasionally interrupted when buoyancy inputs are sufficient to outcompete night-time convection and result in short-term periods of sustained winter stratification, typically lasting 2-3 days. Sustained stratification often coincides with periods of heavy rainfall, suggesting freshwater input from precipitation may play a role on these events by producing a subtle yet significant freshening of the surface layer of the order of 0.005 PSU. Comparing rainfall estimates with observed salinity changes confirms rainfall to often be the initiator of these winter stratification periods. As winter winds subside and solar heating increases towards spring, the water column becomes more susceptible to periods of halo-stratification, such that heavy rainfall during the winter-spring transition is likely to promote sustained stratification. The timing and extent of a heavy rainfall event in March 2015 does suggest it may be the critical trigger for shelf-wide stratification that eventually instigates the spring bloom. We propose that the timing of these downpours relative to the daily heating cycle can be a triggering mechanism for both short term and seasonal stratification in shelf seas, and so play a critical role in winter and early spring phytoplankton growth and the shelf sea carbon cycle. We further test the importance of this process using historical data, and results from the NEMO-AMM7

Investigation of Stable Atmospheric Stratification Effect on the Dynamics of Descending Vortex Pairs

DOT National Transportation Integrated Search

1979-02-01

The physics of vortex flows in stratified fluids is studied with the objective of determining the influence of stable stratification on the descent of aircraft vortex pairs. Vortex rings descending into linear and discontinuous density stratification...

Representing Reservoir Stratification in Land Surface and Earth System Models

NASA Astrophysics Data System (ADS)

Yigzaw, W.; Li, H. Y.; Leung, L. R.; Hejazi, M. I.; Voisin, N.; Payn, R. A.; Demissie, Y.

2017-12-01

A one-dimensional reservoir stratification modeling has been developed as part of Model for Scale Adaptive River Transport (MOSART), which is the river transport model used in the Accelerated Climate Modeling for Energy (ACME) and Community Earth System Model (CESM). Reservoirs play an important role in modulating the dynamic water, energy and biogeochemical cycles in the riverine system through nutrient sequestration and stratification. However, most earth system models include lake models that assume a simplified geometry featuring a constant depth and a constant surface area. As reservoir geometry has important effects on thermal stratification, we developed a new algorithm for deriving generic, stratified area-elevation-storage relationships that are applicable at regional and global scales using data from Global Reservoir and Dam database (GRanD). This new reservoir geometry dataset is then used to support the development of a reservoir stratification module within MOSART. The mixing of layers (energy and mass) in the reservoir is driven by eddy diffusion, vertical advection, and reservoir inflow and outflow. Upstream inflow into a reservoir is treated as an additional source/sink of energy, while downstream outflow represented a sink. Hourly atmospheric forcing from North American Land Assimilation System (NLDAS) Phase II and simulated daily runoff by ACME land component are used as inputs for the model over the contiguous United States for simulations between 2001-2010. The model is validated using selected observed temperature profile data in a number of reservoirs that are subject to various levels of regulation. The reservoir stratification module completes the representation of riverine mass and heat transfer in earth system models, which is a major step towards quantitative understanding of human influences on the terrestrial hydrological, ecological and biogeochemical cycles.

Stratification during evaporative assembly of multicomponent nanoparticle films

DOE PAGES

Liu, Xiao; Liu, Weiping; Carr, Amanda J.; ...

2018-01-03

Multicomponent coatings with layers comprising different functionalities are of interest for a variety of applications, including electronic devices, energy storage, and biomaterials. Rather than creating such a film using multiple deposition steps, we explore a single-step method to create such films by varying the particle Peclet numbers, Pe. Our hypothesis, based on recent theoretical descriptions of the stratification process, is that by varying particle size and evaporation rate such that Pe of large and small particles are above and below unity, we can create stratified films of polymeric and inorganic particles. In this paper, we present AFM on the surfacemore » composition of films comprising poly(styrene) nanoparticles (diameter 25–90 nm) and silica nanoparticles (diameter 8–14 nm). Previous studies on films containing both inorganic and polymeric particles correspond to large Pe values (e.g., 120–460), while we utilize Pe ~ 0.3–4, enabling us to test theories that have been developed for different regimes of Pe. We demonstrate evidence of stratification and effect of the Pe ratio, although our results agree only qualitatively with theory. Finally, our results also provide validation of recent theoretical descriptions of the film drying process that predict different regimes for large-on-top and small-on-top stratification.« less

Stratification during evaporative assembly of multicomponent nanoparticle films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xiao; Liu, Weiping; Carr, Amanda J.

Multicomponent coatings with layers comprising different functionalities are of interest for a variety of applications, including electronic devices, energy storage, and biomaterials. Rather than creating such a film using multiple deposition steps, we explore a single-step method to create such films by varying the particle Peclet numbers, Pe. Our hypothesis, based on recent theoretical descriptions of the stratification process, is that by varying particle size and evaporation rate such that Pe of large and small particles are above and below unity, we can create stratified films of polymeric and inorganic particles. In this paper, we present AFM on the surfacemore » composition of films comprising poly(styrene) nanoparticles (diameter 25–90 nm) and silica nanoparticles (diameter 8–14 nm). Previous studies on films containing both inorganic and polymeric particles correspond to large Pe values (e.g., 120–460), while we utilize Pe ~ 0.3–4, enabling us to test theories that have been developed for different regimes of Pe. We demonstrate evidence of stratification and effect of the Pe ratio, although our results agree only qualitatively with theory. Finally, our results also provide validation of recent theoretical descriptions of the film drying process that predict different regimes for large-on-top and small-on-top stratification.« less

Factors Influencing the Clinical Stratification of Suitability to Drive after Stroke: A Qualitative Study.

PubMed

Stapleton, Tadhg; Connolly, Deirdre; O'Neill, Desmond

2015-01-01

While a clinical pre-selection screening process for a stroke patient's suitability for driving has been acknowledged, little is known about the factors or processes influencing this screening typically conducted by clinicians practicing at a generalist level. This study explored this clinical stratification process through the use of semi-structured interviews with senior occupational therapists (n = 17) and stroke physicians (n = 7) using qualitative description methodology. The findings revealed a trichotomy stratification of stroke patients for driving in the clinical setting; those who are fit to drive, unfit to drive, and a "maybe" group who need more detailed assessment and observation. Factors that had a major influence on this clinical-based stratification of driving suitability were client's levels of awareness, insight, and impulsivity. A period of prolonged contact with the client was preferential to guide the stratification decision in order for clinicians to build a comprehensive picture of the person. A mix of assessment approaches including standardized assessment but with increased emphasis on naturalistic observation of functional performance underpinned the clinical stratification process. This study uncovers some of the factors and processes influencing the early clinical-based stratification of driving suitability after stroke, and highlights the contribution of the generalist practitioner in the assessment of fitness to drive continuum.

Glacial ocean circulation and stratification explained by reduced atmospheric temperature

NASA Astrophysics Data System (ADS)

Jansen, Malte F.

2017-01-01

Earth’s climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5-10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage.

Glacial ocean circulation and stratification explained by reduced atmospheric temperature

PubMed Central

Jansen, Malte F.

2017-01-01

Earth’s climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5–10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage. PMID:27994158

Are Strong Zonal Winds in Giant Planets Caused by Density-Stratification?

NASA Astrophysics Data System (ADS)

Verhoeven, J.; Stellmach, S.

2012-12-01

One of the most striking features of giant planets like Jupiter and Saturn are the zonal wind patterns observed on their surfaces. The mechanism that drives this differential rotation is still not clearly identified and is currently strongly debated in the astro- and geophysics community. Different mechanisms have been proposed over the last decades. Here, a recently discovered mechanism based on background density stratification (Glatzmaier et al., 2009) is investigated. This mechanism has the potential to overcome known difficulties of previous explanations and its efficiency has been demonstrated in 2-d simulations covering equatorial planes. By performing highly resolved numerical simulations in a local Cartesian geometry, we are able to test the efficiency and functionality of this mechanism in turbulent, rotating convection in three spatial dimensions. The choice of a Cartesian model geometry naturally excludes other known mechanisms capable of producing differential rotation, thus allowing us to investigate the role of density stratification in isolation. Typically, the dynamics can be classified into two main regimes: A regime exhibiting strong zonal winds for weak to moderate thermal driving and a regime where zonal winds are largely absent in the case of a strong thermal forcing. Our results indicate that previous 2-d results must be handled with care and can only explain parts of the full 3-d behavior. We show that the density-stratification mechanism tends to operate in a more narrow parameter range in 3-d as compared to 2-d simulations. The dynamics of the regime transition is shown to differ in both cases, which renders scaling laws derived from two-dimensional studies questionable. Based on our results, we provide estimates for the importance of the density-stratification mechanism for giant planets like Jupiter (strong density stratification), for systems like the Earth's core (weak density stratification) and compare its efficiency with other

Implementing system-wide risk stratification approaches: A review of critical success and failure factors.

PubMed

Huckel Schneider, Carmen; Gillespie, James A; Wilson, Andrew

2017-05-01

Risk stratification has become a widely used tool for linking people identified at risk of health deterioration to the most appropriate evidence-based care. This article systematically reviews recent literature to determine key factors that have been identified as critical enablers and/or barriers to successful implementation of risk stratification tools at a system level. A systematic search found 23 articles and four promising protocols for inclusion in the review, covering the use to 20 different risk stratification tools. These articles reported on only a small fraction of the risk stratification tools used in health systems; suggesting that while the development and statistical validation of risk stratification algorithms is widely reported, there has been little published evaluation of how they are implemented in real-world settings. Controlled studies provided some evidence that the use of risk stratification tools in combination with a care management plan offer patient benefits and that the use of a risk stratification tool to determine components of a care management plan may contribute to reductions in hospital readmissions, patient satisfaction and improved patient outcomes. Studies with the strongest focus on implementation used qualitative and case study methods. Among these, the literature converged on four key areas of implementation that were found to be critical for overcoming barriers to success: the engagement of clinicians and safeguarding equity, both of which address barriers of acceptance; the health system context to address administrative, political and system design barriers; and data management and integration to address logistical barriers.

Development of thermal stratification and destratification scaling concepts. Volume 2: Stratification. [tanks (containers)/tables (data)

NASA Technical Reports Server (NTRS)

Lovrich, T. N.; Schwartz, S. H.

1975-01-01

Temperature and pressure data obtained from the saturated Freon 113 PCA closed-tank stratification tests are presented. The data presented in tabular form are the test conditions, sensible heat values, and Freon 113 PCA liquid and ullage (vapor) properties. Also included, are graphical representations of the liquid bulk temperature and pressure histories, and dimensionless liquid-ullage delta-temperature profiles. Modified Grashof numbers and Fourier number-history data are also presented graphically.

Changes in oxidative patterns during dormancy break by warm and cold stratification in seeds of an edible fruit tree

PubMed Central

Shalimu, Dilinuer; Sun, Jia; Baskin, Carol C.; Baskin, Jerry M.; Sun, Liwei; Liu, Yujun

2016-01-01

The transition from seed dormancy to germination is triggered by environmental factors, and in pomegranate (Punica granatum) seeds higher germination percentages are achieved by warm + cold stratification rather than by cold stratification alone. Our objective was to define the pattern of internal oxidative changes in pomegranate seeds as dormancy was being broken by warm + cold stratification and by cold stratification alone. Embryos isolated from seeds after 1–42 days of warm stratification, after 56 days of warm stratification + 7, 28 or 56 days of cold stratification, and after 1–84 days of cold stratification alone, were used in biochemical tests. Hydrogen peroxide (H2O2), nitric oxide (NO), proline, lipid peroxidation, protein carbonylation, and activities of the scavenging enzymes superoxide dismutase (SOD), hydrogen peroxide enzyme and peroxidase in the embryos were assessed by colorimetric methods. Our results indicated that warm + cold stratification had a stronger dormancy-breaking effect than cold stratification (85% versus 50% germination), which may be attributed to a higher yield of H2O2, NO, lipid peroxidation and protein carbonylation in warm + cold stratification. Furthermore, warm + cold stratification-induced H2O2 change led to greater changes (elevation followed by attenuation) in activities of the scavenging enzymes than that induced by cold stratification alone. These results indicated that restriction of the level of reactive oxygen species change within a positive and safe range by such enzymes promoted seed germination. In addition, a relatively strong elevation of proline during warm + cold stratification also contributed to dormancy breakage and subsequent germination. In conclusion, the strong dormancy alleviating effect of warm + cold stratification on pomegranate seeds may be attributed to the corresponding active oxidative change via H2O2, NO, proline, malondialdehyde, protein carbonylation and

Principes et réalisation d'une chaîne laser femtoseconde haute intensité basée sur le saphir dopé au titane

NASA Astrophysics Data System (ADS)

Le Blanc, Catherine

égime femtosecondes. Cette installation est capable de produire sur cible des intensités supérieures à 10^18 W/cm2 à une récurrence de 10 tirs par seconde. Nous présentons tout d'abord les principes fondamentaux de la propagation d'impulsions étirées dans un milieu amplificateur en mettant en évidence les principaux mécanismes mis en jeu dans ce processus : la dispersion de vitesse de groupe, l'automodulation de phase, l'autofocalisation et la saturation du gain. Une analyse des différentes possibilités quant au choix de la source initiale capable d'émettre des impulsions de durée femtoseconde dans le domaine du proche infrarouge est réalisée après la présentation des caractéristiques spectroscopiques du saphir dopé au titane. Sont en particulier décrits en détail le principe et le fonctionnement de l'oscillateur au saphir dopé au titane à autoblocage de modes que nous avons construit à cet effet. L'amplification jusqu'aux puissances de l'ordre du terawatt repose sur le concept "CPA" d'amplification d'impulsions à dérive de fréquence. Nous explorons ici la voie des amplificateurs à multipassages suivant des configurations déjà développées pour les amplificateurs à colorants. Une attention particulière a été portée sur les méthodes de réglage, la fiabilité, la stabilité et la qualité du profil spatial du faisceau. D'autre part, une modélisation rend parfaitement compte des effets de saturation dans les amplificateurs. Les impulsions obtenues après compression ont une énergie de l'ordre de 60 mJ et une durée de l'ordre de 130 fs. La partie suivante est consacrée à une étude des problèmes d'étirement et de recompression pour tenter d'expliquer les raisons de cette recompression imparfaite. Finalement, un paramètre encore plus crucial pour la physique de l'interaction sur cible solide sans création d'un préplasma est le contraste des impulsions. Nous décrivons donc l'appareil de mesure capable d'effectuer des autocorrélations avec

The formation of low-angle eolian stratification through the migration of protodunes

NASA Astrophysics Data System (ADS)

Ewing, R. C.; Phillips, J. D.; Weymer, B. A.; Barrineaux, P.; Bowling, R.; Nittrouer, J. A.

2017-12-01

Protodunes are low-relief, slipfaceless migrating bed forms that represent the emergent form of eolian sand dunes. Protodunes develop as cm-scale topography out of a flat bed of sand and evolve spatially and temporally into dunes with angle-of-repose slipfaces. Protodunes at White Sands Dune Field in New Mexico form at the upwind, trailing margin of the field, on dune stoss slopes, and in interdune areas. Here we analyze protodunes at the upwind margin of White Sands by coupling 200 mHz ground penetrating radar (GPR) with time-series high-resolution topography to characterize the origin and evolution of protodune stratification and the stratigraphic transition into fully developed dunes. We surveyed a 780m transect in the resultant transport direction of the dune field from SW to NE from sand patches through protodunes and into the first dune. We used airborne lidar surveys and structure-from-motion photogrammetry from 2007, 2008, 2009, 2010, 2015, and 2016. We find that protodune stratification forms at angles between 0-10 degrees by protodune migration. Dip angles increase as protodune amplitude increases along the transect. Accumulation of low-angle stratification increases across the first 650m and ranges from none to subcritical. Nearly aggradational accumulation of low-angle stratification occurs over the last 100m and is a precursor to angle-of-repose slipface formation. The origins of the aggradation and slipface development appear to be linked to protodune merging, dune interactions, and possibly to the development of a dune field-scale boundary layer. Protodunes and the formation of low-angle stratification at the upwind margin of White Sands are a good analog to the initiation of dune field development from sand sheets and the formation of low-angle stratification found at the base of eolian successions in the stratigraphic record.

Investigating Summer Thermal Stratification in Lake Ontario

NASA Astrophysics Data System (ADS)

James, S. C.; Arifin, R. R.; Craig, P. M.; Hamlet, A. F.

2017-12-01

Seasonal temperature variations establish strong vertical density gradients (thermoclines) between the epilimnion and hypolimnion. Accurate simulation of vertical mixing and seasonal stratification of large lakes is a crucial element of the thermodynamic coupling between lakes and the atmosphere in integrated models. Time-varying thermal stratification patterns can be accurately simulated with the versatile Environmental Fluid Dynamics Code (EFDC). Lake Ontario bathymetry was interpolated onto a 2-km-resolution curvilinear grid with vertical layering using a new approach in EFDC+, the so-called "sigma-zed" coordinate system which allows the number of vertical layers to be varied based on water depth. Inflow from the Niagara River and outflow to the St. Lawrence River in conjunction with hourly meteorological data from seven local weather stations plus three-hourly data from the North American Regional Reanalysis govern the hydrodynamic and thermodynamic responses of the Lake. EFDC+'s evaporation algorithm was updated to more accurately simulate net surface heat fluxes. A new vertical mixing scheme from Vinçon-Leite that implements different eddy diffusivity formulations above and below the thermocline was compared to results from the original Mellor-Yamada vertical mixing scheme. The model was calibrated by adjusting solar-radiation absorption coefficients in addition to background horizontal and vertical mixing parameters. Model skill was evaluated by comparing measured and simulated vertical temperature profiles at shallow (20 m) and deep (180 m) locations on the Lake. These model improvements, especially the new sigma-zed vertical discretization, accurately capture thermal-stratification patterns with low root-mean-squared errors when using the Vinçon-Leite vertical mixing scheme.

Cardiac risk stratification: Role of the coronary calcium score

PubMed Central

Sharma, Rakesh K; Sharma, Rajiv K; Voelker, Donald J; Singh, Vibhuti N; Pahuja, Deepak; Nash, Teresa; Reddy, Hanumanth K

2010-01-01

Coronary artery calcium (CAC) is an integral part of atherosclerotic coronary heart disease (CHD). CHD is the leading cause of death in industrialized nations and there is a constant effort to develop preventative strategies. The emphasis is on risk stratification and primary risk prevention in asymptomatic patients to decrease cardiovascular mortality and morbidity. The Framingham Risk Score predicts CHD events only moderately well where family history is not included as a risk factor. There has been an exploration for new tests for better risk stratification and risk factor modification. While the Framingham Risk Score, European Systematic Coronary Risk Evaluation Project, and European Prospective Cardiovascular Munster study remain excellent tools for risk factor modification, the CAC score may have additional benefit in risk assessment. There have been several studies supporting the role of CAC score for prediction of myocardial infarction and cardiovascular mortality. It has been shown to have great scope in risk stratification of asymptomatic patients in the emergency room. Additionally, it may help in assessment of progression or regression of coronary artery disease. Furthermore, the CAC score may help differentiate ischemic from nonischemic cardiomyopathy. PMID:20730016

Effect of gravitational stratification on the propagation of a CME

NASA Astrophysics Data System (ADS)

Pagano, P.; Mackay, D. H.; Poedts, S.

2013-12-01

Context. Coronal mass ejections (CMEs) are the most violent phenomenon found on the Sun. One model that explains their occurrence is the flux rope ejection model. A magnetic flux rope is ejected from the solar corona and reaches the interplanetary space where it interacts with the pre-existing magnetic fields and plasma. Both gravity and the stratification of the corona affect the early evolution of the flux rope. Aims: Our aim is to study the role of gravitational stratification on the propagation of CMEs. In particular, we assess how it influences the speed and shape of CMEs and under what conditions the flux rope ejection becomes a CME or when it is quenched. Methods: We ran a set of MHD simulations that adopt an eruptive initial magnetic configuration that has already been shown to be suitable for a flux rope ejection. We varied the temperature of the backgroud corona and the intensity of the initial magnetic field to tune the gravitational stratification and the amount of ejected magnetic flux. We used an automatic technique to track the expansion and the propagation of the magnetic flux rope in the MHD simulations. From the analysis of the parameter space, we evaluate the role of gravitational stratification on the CME speed and expansion. Results: Our study shows that gravitational stratification plays a significant role in determining whether the flux rope ejection will turn into a full CME or whether the magnetic flux rope will stop in the corona. The CME speed is affected by the background corona where it travels faster when the corona is colder and when the initial magnetic field is more intense. The fastest CME we reproduce in our parameter space travels at ~850 km s-1. Moreover, the background gravitational stratification plays a role in the side expansion of the CME, and we find that when the background temperature is higher, the resulting shape of the CME is flattened more. Conclusions: Our study shows that although the initiation mechanisms of the

Quantitative risk stratification in Markov chains with limiting conditional distributions.

PubMed

Chan, David C; Pollett, Philip K; Weinstein, Milton C

2009-01-01

Many clinical decisions require patient risk stratification. The authors introduce the concept of limiting conditional distributions, which describe the equilibrium proportion of surviving patients occupying each disease state in a Markov chain with death. Such distributions can quantitatively describe risk stratification. The authors first establish conditions for the existence of a positive limiting conditional distribution in a general Markov chain and describe a framework for risk stratification using the limiting conditional distribution. They then apply their framework to a clinical example of a treatment indicated for high-risk patients, first to infer the risk of patients selected for treatment in clinical trials and then to predict the outcomes of expanding treatment to other populations of risk. For the general chain, a positive limiting conditional distribution exists only if patients in the earliest state have the lowest combined risk of progression or death. The authors show that in their general framework, outcomes and population risk are interchangeable. For the clinical example, they estimate that previous clinical trials have selected the upper quintile of patient risk for this treatment, but they also show that expanded treatment would weakly dominate this degree of targeted treatment, and universal treatment may be cost-effective. Limiting conditional distributions exist in most Markov models of progressive diseases and are well suited to represent risk stratification quantitatively. This framework can characterize patient risk in clinical trials and predict outcomes for other populations of risk.

Randomization in clinical trials: stratification or minimization? The HERMES free simulation software.

PubMed

Fron Chabouis, Hélène; Chabouis, Francis; Gillaizeau, Florence; Durieux, Pierre; Chatellier, Gilles; Ruse, N Dorin; Attal, Jean-Pierre

2014-01-01

Operative clinical trials are often small and open-label. Randomization is therefore very important. Stratification and minimization are two randomization options in such trials. The first aim of this study was to compare stratification and minimization in terms of predictability and balance in order to help investigators choose the most appropriate allocation method. Our second aim was to evaluate the influence of various parameters on the performance of these techniques. The created software generated patients according to chosen trial parameters (e.g., number of important prognostic factors, number of operators or centers, etc.) and computed predictability and balance indicators for several stratification and minimization methods over a given number of simulations. Block size and proportion of random allocations could be chosen. A reference trial was chosen (50 patients, 1 prognostic factor, and 2 operators) and eight other trials derived from this reference trial were modeled. Predictability and balance indicators were calculated from 10,000 simulations per trial. Minimization performed better with complex trials (e.g., smaller sample size, increasing number of prognostic factors, and operators); stratification imbalance increased when the number of strata increased. An inverse correlation between imbalance and predictability was observed. A compromise between predictability and imbalance still has to be found by the investigator but our software (HERMES) gives concrete reasons for choosing between stratification and minimization; it can be downloaded free of charge. This software will help investigators choose the appropriate randomization method in future two-arm trials.

Observations and analysis of a stratification-destratification event in a tropical estuary

NASA Astrophysics Data System (ADS)

Uncles, R. J.; Ong, J. E.; Gong, W. K.

1990-11-01

A data set comprising 31 continuous tidal cycles was collected in the Sungai Merbok Estuary, Malaysia, in June 1987 as part of an ecological study of nutrient fluxes from a tropical mangrove estuary. Currents, salinity and salinity stratification at a deep-channel (15 m) station near the mouth of the Merbok Estuary showed a pronounced spring-neap variability. The slow currents and weak vertical mixing at neap tides favoured the formation of a stratified water column and generated a neap-spring cycle of water column stabilization and destabilization. A strong stratification event occurred during the period of observations. This was partly driven by a modest freshwater spate which coincided with neap tides. An eddy viscosity-diffusivity model of the stratification, which assumed a constant, longitudinal salinity gradient, demonstrated a pronounced stratification-destratification cycle due to neap-spring variations in vertical mixing. Larger and more realistic stratification was modelled when the estimated, time-varying longitudinal salinity gradient was incorporated. This gradient maximized in response to the peak in freshwater runoff. The measured and modelled density-driven circulations showed qualitative similarities and were of the order of 10 cm s -1 at neap tides. The circulation was weaker during spring tides. The tidally-filtered salt transport due to vertical shear was directed up-estuary and was an order of magnitude smaller during spring tides. The results are discussed in terms of their relevance to mangrove system oceanography.

Evaluation d'une approche pedagogique respectant les facons d'apprendre des filles en sciences et en TIC en 9e annee au Nouveau-Brunswick

NASA Astrophysics Data System (ADS)

Lirette-Pitre, Nicole T.

2009-07-01

La reussite scolaire des filles les amene de plus en plus a poursuivre une formation postsecondaire et a exercer des professions qui demandent un haut niveau de connaissances et d'expertise scientifique. Toutefois, les filles demeurent toujours tres peu nombreuses a envisager une carriere en sciences (chimie et physique), en ingenierie ou en TIC (technologie d'information et de la communication), soit une carriere reliee a la nouvelle economie. Pour plusieurs filles, les sciences et les TIC ne sont pas des matieres scolaires qu'elles trouvent interessantes meme si elles y reussissent tres bien. Ces filles admettent que leurs experiences d'apprentissage en sciences et en TIC ne leur ont pas permis de developper un interet ni de se sentir confiante en leurs habiletes a reussir dans ces matieres. Par consequent, peu de filles choisissent de poursuivre leurs etudes postsecondaires dans ces disciplines. La theorie sociocognitive du choix carriere a ete choisie comme modele theorique pour mieux comprendre quelles variables entrent en jeu lorsque les filles choisissent leur carriere. Notre etude a pour objet la conception et l'evaluation de l'efficacite d'un materiel pedagogique concu specifiquement pour ameliorer les experiences d'apprentissage en sciences et en TIC des filles de 9e annee au Nouveau-Brunswick. L'approche pedagogique privilegiee dans notre materiel a mis en oeuvre des strategies pedagogiques issues des meilleures pratiques que nous avons identifiees et qui visaient particulierement l'augmentation du sentiment d'auto-efficacite et de l'interet des filles pour ces disciplines. Ce materiel disponible par Internet a l'adresse http://www.umoncton.ca/lirettn/scientic est directement en lien avec le programme d'etudes en sciences de la nature de 9e annee du Nouveau-Brunswick. L'evaluation de l'efficacite de notre materiel pedagogique a ete faite selon deux grandes etapes methodologiques: 1) l'evaluation de l'utilisabilite et de la convivialite du materiel et 2

Response of water temperatures and stratification to changing climate in three lakes with different morphometry

NASA Astrophysics Data System (ADS)

Magee, Madeline R.; Wu, Chin H.

2017-12-01

Water temperatures and stratification are important drivers for ecological and water quality processes within lake systems, and changes in these with increases in air temperature and changes to wind speeds may have significant ecological consequences. To properly manage these systems under changing climate, it is important to understand the effects of increasing air temperatures and wind speed changes in lakes of different depths and surface areas. In this study, we simulate three lakes that vary in depth and surface area to elucidate the effects of the observed increasing air temperatures and decreasing wind speeds on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes) over a century (1911-2014). For all three lakes, simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, stability increased, and longwave and sensible heat fluxes at the surface increased. Overall, lake depth influences the presence of stratification, Schmidt stability, and differences in surface heat flux, while lake surface area influences differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates. Larger surface area lakes have greater wind mixing due to increased surface momentum. Climate perturbations indicate that our larger study lakes have more variability in temperature and stratification variables than the smaller lakes, and this variability increases with larger wind speeds. For all study lakes, Pearson correlations and climate perturbation scenarios indicate that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature, and wind can act to either amplify or mitigate the effect of warmer air temperatures on lake thermal

Changes in oxidative patterns during dormancy break by warm and cold stratification in seeds of an edible fruit tree.

PubMed

Shalimu, Dilinuer; Sun, Jia; Baskin, Carol C; Baskin, Jerry M; Sun, Liwei; Liu, Yujun

2016-01-01

The transition from seed dormancy to germination is triggered by environmental factors, and in pomegranate (Punica granatum) seeds higher germination percentages are achieved by warm + cold stratification rather than by cold stratification alone. Our objective was to define the pattern of internal oxidative changes in pomegranate seeds as dormancy was being broken by warm + cold stratification and by cold stratification alone. Embryos isolated from seeds after 1-42 days of warm stratification, after 56 days of warm stratification + 7, 28 or 56 days of cold stratification, and after 1-84 days of cold stratification alone, were used in biochemical tests. Hydrogen peroxide (H2O2), nitric oxide (NO), proline, lipid peroxidation, protein carbonylation, and activities of the scavenging enzymes superoxide dismutase (SOD), hydrogen peroxide enzyme and peroxidase in the embryos were assessed by colorimetric methods. Our results indicated that warm + cold stratification had a stronger dormancy-breaking effect than cold stratification (85% versus 50% germination), which may be attributed to a higher yield of H2O2, NO, lipid peroxidation and protein carbonylation in warm + cold stratification. Furthermore, warm + cold stratification-induced H2O2 change led to greater changes (elevation followed by attenuation) in activities of the scavenging enzymes than that induced by cold stratification alone. These results indicated that restriction of the level of reactive oxygen species change within a positive and safe range by such enzymes promoted seed germination. In addition, a relatively strong elevation of proline during warm + cold stratification also contributed to dormancy breakage and subsequent germination. In conclusion, the strong dormancy alleviating effect of warm + cold stratification on pomegranate seeds may be attributed to the corresponding active oxidative change via H2O2, NO, proline, malondialdehyde, protein carbonylation and

Filling box stratification fed by a gravity current

NASA Astrophysics Data System (ADS)

Hogg, Charlie; Huppert, Herbert; Imberger, Jorg

2012-11-01

Fluids in confined basins can be stratified by the filling box mechanism. The source of dense fluid in geophysical applications, such as a cold river entering a warmer lake, can be a gravity current running over a shallow slope. Filling box models are often, however, based on the dynamics of vertically falling, unconfined, plumes which entrain fluid by a different mechanism to gravity currents on shallow slopes. Laboratory tank experiments of a filling box fed by a gravity current running over a shallow slope were carried out using a dye attenuation technique to investigate the development of the stratification of the ambient. These results demonstrate the differences in the stratification generated by a gravity current compared to that generated by a plume and demonstrate the nature of entrainment into gravity currents on shallow slopes.

Fistule vesico-sigmoïdienne compliquant une hydatidose intestinale: à propos d'un cas rare

PubMed Central

Lahyani, Mounir; Jabbour, Younes; Karmouni, Tarik; Elkhader, Khalid; Koutani, Abdellatif; Andaloussi, Ahmed Ibn attya

2014-01-01

La fistule colo-vésicale sur une hydatidose sigmoidienne est une entité pathologique exceptionnelle. Nous rapportions une nouvelle observation, ou seront rappelées les principales données diagnostique et thérapeutique de cette affection. PMID:25722790

Urban noise functional stratification for estimating average annual sound level.

PubMed

Rey Gozalo, Guillermo; Barrigón Morillas, Juan Miguel; Prieto Gajardo, Carlos

2015-06-01

Road traffic noise causes many health problems and the deterioration of the quality of urban life; thus, adequate spatial noise and temporal assessment methods are required. Different methods have been proposed for the spatial evaluation of noise in cities, including the categorization method. Until now, this method has only been applied for the study of spatial variability with measurements taken over a week. In this work, continuous measurements of 1 year carried out in 21 different locations in Madrid (Spain), which has more than three million inhabitants, were analyzed. The annual average sound levels and the temporal variability were studied in the proposed categories. The results show that the three proposed categories highlight the spatial noise stratification of the studied city in each period of the day (day, evening, and night) and in the overall indicators (L(And), L(Aden), and L(A24)). Also, significant differences between the diurnal and nocturnal sound levels show functional stratification in these categories. Therefore, this functional stratification offers advantages from both spatial and temporal perspectives by reducing the sampling points and the measurement time.

Variability of stratification according to operation of the tidal power plant in Lake Sihwa, South Korea.

NASA Astrophysics Data System (ADS)

Woo, S. B.; Song, J. I.; Jang, T. H.; Park, C. J.; Kwon, H. K.

2017-12-01

Artificial forcing according to operation of the tidal power plant (TPP) affects the physical environmental changes near the power plant. Strong turbulence by generation is expected to change the stratification structure of the Lake Sihwa inside. In order to examine the stratification changes by the power plant operation, ship bottom mounted observation were performed for 13 hours using an acoustic Doppler current profiler (ADCP) and Conductivity-Temperature-Depth (CTD) in Lake Sihwa at near TPP. The strong stratification in Sihwa Lake is maintained before TPP operation. The absence of external forces and freshwater inflow from the land forms the stratification in the Lake. Strong winds in a stratification statement lead to two-layer circulation. After wind event, multi-layer velocity structure is formed which lasted for approximately 4 h. After TPP operation, the jet flow was observed in entire water column at the beginning of the power generation. Vortex is formed by strong jet flow and maintained throughout during power generation period. Strong turbulence flow is generated by the turbine blades, enhancing vertical mixing. External forces, which dominantly affect Lake Sihwa, have changed from the wind to the turbulent flow. The stratification was extinguished by strong turbulent flow and becomes fully-mixed state. Changes in stratification structure are expected to affect material transport and ecological environment change continuously.

Maladie de Horton révélée par une dyspnée

PubMed Central

Mahfoudhi, Madiha; Mamlouk, Habiba; Turki, Sami; Kheder, Adel

2015-01-01

Les manifestations pleuro-pulmonaires de la maladie de Horton sont rares et peu connues. Elles peuvent être inaugurales, à l'origine d'un retard à la prise en charge si elles sont méconnues. Il s'agissait d'un patient âgé de 75 ans, admis pour une dyspnée, une toux chronique et une fièvre. Il a reçu une antibiothérapie et a bénéficié d'une fibroscopie bronchique avec lavage broncho-alvéolaire à la recherche d'un germe, qui a révélé plutôt, une alvéolite lymphocytaire. L’évolution était marquée par la persistance des signes cliniques et du syndrome inflammatoire biologique. Un angio-scanner thoracique et une échographie cardiaque étaient sans anomalies. Une origine cardiaque, musculaire, hématologique, néoplasique, vasculaire ou métabolique de la dyspnée a été éliminée. Une maladie de Horton a été évoquée. La biopsie de l'artère temporale a confirmé le diagnostic d'une maladie de Horton. L’évolution sous corticothérapie était marquée par la disparition des signes cliniques et biologiques. Les manifestations pleuro-pulmonaires au cours de la maladie de Horton sont rares, et classiquement, rarement révélatrices de la maladie. La dyspnée peut initialement égarer le diagnostic vers d'autres étiologies notamment infectieuses. Le but de ce travail est d'insister sur le fait que la connaissance de ces différentes manifestations respiratoires au cours de la maladie de Horton (toux persistante, dyspnée, épanchement pleural) est utile au clinicien afin de prescrire une corticothérapie, chez un sujet le plus souvent âgé ayant un état fébrile et inflammatoire prolongé, permettant ainsi d’éviter l'apparition de complications. PMID:26161171

Modern risk stratification in coronary heart disease.

PubMed

Ginghina, C; Bejan, I; Ceck, C D

2011-11-14

The prevalence and impact of cardiovascular diseases in the world are growing. There are 2 million deaths due to cardiovascular disease each year in the European Union; the main cause of death being the coronary heart disease responsible for 16% of deaths in men and 15% in women. Prevalence of cardiovascular disease in Romania is estimated at 7 million people, of which 2.8 million have ischemic heart disease. In this epidemiological context, risk stratification is required for individualization of therapeutic strategies for each patient. The continuing evolution of the diagnosis and treatment techniques combines personalized medicine with the trend of therapeutic management leveling, based on guidelines and consensus, which are in constant update. The guidelines used in clinical practice have involved risk stratification and identification of patient groups in whom the risk-benefit ratio of using new diagnostic and therapeutic techniques has a positive value. Presence of several risk factors may indicate a more important total risk than the presence / significant increase from normal values of a single risk factor. Modern trends in risk stratification of patients with coronary heart disease are polarized between the use of simple data versus complex scores, traditional data versus new risk factors, generally valid scores versus personalized scores, depending on patient characteristics, type of coronary artery disease, with impact on the suggested therapy. All known information and techniques can be integrated in a complex system of risk assessment. The current trend in risk assessment is to identify coronary artery disease in early forms, before clinical manifestation, and to guide therapy, particularly in patients with intermediate risk, which can be classified in another class of risk based on new obtained information.

Etiologie Rare de Sinusites Nosocomiales en Milieu de Reanimation - A Propos d'une Observation

PubMed Central

Messadi, A.A.; Oueslati, S.; Thabet, L.; Bousselmi, K.; Menif, E.

2006-01-01

Summary Les sinusites nosocomiales ne sont pas rares en réanimation. Elles surviennent en général dans les suites d'une intubation nasotrachéale voire même orotrachéale. Le tubage gastrique peut être à lui seul à l'origine d'une sinusite nosocomiale. Nous rapportons le cas d'une patiente hospitalisée qui a été victime de brûlures étendues chez qui la sonde nasogastrique a été à l'origine d'une pansinusite dont l'issue a été fatale. PMID:21991055

High aeration rate enhances flow stratification in full-scale oxidation ditch.

PubMed

Diamantis, Vasileios; Papaspyrou, Ioannis; Melidis, Parasxos; Aivasidis, Alexander

2010-02-01

Aerated channel reactors with a uniform field of aeration may display flow stratification and short-circuit phenomena in wastewater treatment systems. In this study, we present data suggesting that flow stratification is closely related to the aeration rate and the arrangement of aerators. A full-scale oxidation ditch, with a total volume of 6,500 m(3) and a membrane-diffused aerated zone of 60 x 7 x 5 m (length-width-depth), was selected for water velocity measurements. Two profiles of the oxidation ditch were studied in detail: the first one was at the end of the aerated zone and the second one at the end of the anoxic zone. The results of this work demonstrate that the horizontal water velocity at the end of the aerated zone displayed significant stratification, with maximum velocity near the water surface (0.5-0.7 m/s) and almost zero velocity at a depth of 2.5 m. At the end of the anoxic zone, water velocity was uniform and equal to 0.27-0.31 m/s. Increasing the aeration rate from 1,800 to 4,300 m(3)/h, almost 90% of the water flow was found to discharge through the upper-half of the channel reactor profile. Different options to mitigate flow stratification of the oxidation ditch are discussed in this paper.

Numerical solution of chemically reactive non-Newtonian fluid flow: Dual stratification

NASA Astrophysics Data System (ADS)

Rehman, Khalil Ur; Malik, M. Y.; Khan, Abid Ali; Zehra, Iffat; Zahri, Mostafa; Tahir, M.

2017-12-01

We have found that only a few attempts are available in the literature relatively to the tangent hyperbolic fluid flow induced by stretching cylindrical surfaces. In particular, temperature and concentration stratification effects have not been investigated until now with respect to the tangent hyperbolic fluid model. Therefore, we have considered the tangent hyperbolic fluid flow induced by an acutely inclined cylindrical surface in the presence of both temperature and concentration stratification effects. To be more specific, the fluid flow is attained with the no slip condition, which implies that the bulk motion of the fluid particles is the same as the stretching velocity of a cylindrical surface. Additionally, the flow field situation is manifested with heat generation, mixed convection and chemical reaction effects. The flow partial differential equations give a complete description of the present problem. Therefore, to trace out the solution, a set of suitable transformations is introduced to convert these equations into ordinary differential equations. In addition, a self-coded computational algorithm is executed to inspect the numerical solution of these reduced equations. The effect logs of the involved parameters are provided graphically. Furthermore, the variations of the physical quantities are examined and given with the aid of tables. It is observed that the fluid temperature is a decreasing function of the thermal stratification parameter and a similar trend is noticed for the concentration via the solutal stratification parameter.

Potential Impacts of Offshore Wind Farms on North Sea Stratification

PubMed Central

Carpenter, Jeffrey R.; Merckelbach, Lucas; Callies, Ulrich; Clark, Suzanna; Gaslikova, Lidia; Baschek, Burkard

2016-01-01

Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions—both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios. PMID:27513754

Potential Impacts of Offshore Wind Farms on North Sea Stratification.

PubMed

Carpenter, Jeffrey R; Merckelbach, Lucas; Callies, Ulrich; Clark, Suzanna; Gaslikova, Lidia; Baschek, Burkard

2016-01-01

Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions-both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios.

External validation of scoring systems in risk stratification of upper gastrointestinal bleeding.

PubMed

Anchu, Anna Cherian; Mohsina, Subair; Sureshkumar, Sathasivam; Mahalakshmy, T; Kate, Vikram

2017-03-01

The aim of this study was to externally validate the four commonly used scoring systems in the risk stratification of patients with upper gastrointestinal bleed (UGIB). Patients of UGIB who underwent endoscopy within 24 h of presentation were stratified prospectively using the pre-endoscopy Rockall score (PRS) >0, complete Rockall score (CRS) >2, Glasgow Blatchford bleeding scores (GBS) >3, and modified GBS (m-GBS) >3 scores. Patients were followed up to 30 days. Prognostic accuracy of the scores was done by comparing areas under curve (AUC) in terms of overall risk stratification, re-bleeding, mortality, need for intervention, and length of hospitalization. One hundred and seventy-five patients were studied. All four scores performed better in the overall risk stratification on AUC [PRS = 0.566 (CI: 0.481-0.651; p-0.043)/CRS = 0.712 (CI: 0.634-0.790); p<0.001)/GBS = 0.810 (CI: 0.744-0.877; p->0.001); m-GBS = 0.802 (CI: 0.734-0.871; p<0.001)], whereas only CRS achieved significance in identifying re-bleed [AUC-0.679 (CI: 0.579-0.780; p = 0.003)]. All the scoring systems except PRS were found to be significantly better in detecting 30-day mortality with a high AUC (CRS = 0.798; p-0.042)/GBS = 0.833; p-0.023); m-GBS = 0.816; p-0.031). All four scores demonstrated significant accuracy in the risk stratification of non-variceal patients; however, only GBS and m-GBS were significant in variceal etiology. Higher cutoff scores achieved better sensitivity/specificity [RS > 0 (50/60.8), CRS > 1 (87.5/50.6), GBS > 7 (88.5/63.3), m-GBS > 7(82.3/72.6)] in the risk stratification. GBS and m-GBS appear to be more valid in risk stratification of UGIB patients in this region. Higher cutoff values achieved better predictive accuracy.

Social Stratification: A Modular Approach. Cultural Anthropology.

ERIC Educational Resources Information Center

Kassebaum, Peter

Designed for use as supplementary instructional material in a cultural anthropology course, this learning module introduces students to the basic concepts of social stratification, one of the more controversial areas of contemporary social theory. An overview is provided of the explanations that have been put forth by social philosophers for…

Summer Stratification and Fall Overturn--In a Jar.

ERIC Educational Resources Information Center

Foley, Arlene F.

1984-01-01

Provided are procedures for a demonstration which illustrates the concept of summer stratification of lakes in the temperate zone as maintained by thermal resistance to mixing. The demonstration requires only food coloring, water, and common laboratory equipment. (JN)

New Methods for the Analysis of Heartbeat Behavior in Risk Stratification

PubMed Central

Glass, Leon; Lerma, Claudia; Shrier, Alvin

2011-01-01

Developing better methods for risk stratification for tachyarrhythmic sudden cardiac remains a major challenge for physicians and scientists. Since the transition from sinus rhythm to ventricular tachycardia/fibrillation happens by different mechanisms in different people, it is unrealistic to think that a single measure will be adequate to provide a good index for risk stratification. We analyze the dynamical properties of ventricular premature complexes over 24 h in an effort to understand the underlying mechanisms of ventricular arrhythmias and to better understand the arrhythmias that occur in individual patients. Two dimensional density plots, called heartprints, correlate characteristic features of the dynamics of premature ventricular complexes and the sinus rate. Heartprints show distinctive characteristics in individual patients. Based on a better understanding of the natures of transitions from sinus rhythm to sudden cardiac and the mechanisms of arrhythmia prior to cardiac arrest, it should be possible to develop better methods for risk stratification. PMID:22144963

Quand la biopsie cutanée peut étiqueter une épilepsie

PubMed Central

Harmouch, Taoufiq; Gallouj, Salim; Znati, Kaoutar; Sennou, Aicha Slassi; Belahcen, Faouzi; Amarti, Afaf

2011-01-01

La maladie de Lafora (ML) représente une forme rare et grave d’épilepsie myoclonique progressive. C'est une affection à transmission autosomique récessive, hétérogène sur le plan génétique. Nous rapportons le cas d'une adolescente de 16 ans, issue de parents consanguins de premier degré, qui présente depuis l’âge de 14 ans des crises d’épilepsie et des myoclonies. L'examen neurologique a montré un syndrome cérébelleux et une détérioration intellectuelle. La biopsie cutanée était indispensable pour orienter le diagnostic. La ML a un pronostic constamment fatal. L’étude histologique confirme le diagnostic et l’étude moléculaire peut aider à établir un conseil génétique. PMID:22187608

Stratification on the Skagit Bay Tidal Flats

DTIC Science & Technology

2012-09-01

and wind -driven currents can 11 affect the potential energy anomaly balance in estuaries and ROFIs during storms (Yang and Khangaonkar, 2009...30 3.4.1 The Potential Energy Anomaly Balance...turbulent energy is dissipated by destabilizing the fluid rather than by slowing the upper water column (Turner, 1973). Overall, stratification tends to

Sidération myocardique au cours d'une intoxication au monoxyde de carbone (CO) chez une femme enceinte

PubMed Central

Coulibaly, Mahamadoun; Berdai, Mohamed Adnane; Labib, Smael; Harandou, Mustapha

2015-01-01

L'intoxication au monoxyde de carbone (CO) est la première cause de décès par intoxication en France. La littérature est ancienne et peu connue. Les signes les plus fréquents de l'intoxication sont la triade: Céphalées; asthénie, faiblesse musculaire surtout des membres inférieurs. Ses conséquences sont potentiellement graves pour le fœtus quand elle survient chez la femme enceinte, il est particulièrement exposé au risque d'hypoxie en raison de la forte affinité de son hémoglobine pour le CO qui traverse aisément le placenta. Les événements cardiovasculaires ne sont pas rares et peuvent être responsable d'une morbi-mortalité assez importante qui peuvent être d'apparition rapide ou secondaire mais régressent habituellement en quelques jours. Des SCA peuvent survenir lors d'une une intoxication au CO avec à l'extrême infarctus myocardique avec surélévation du segment ST. Il paraît légitime de proposer pour toutes les patientes: l’éloignement maternel de la source de CO; l'oxygénothérapie à 100% au masque facial par les services de secours et pendant le transfert; le traitement par oxygénothérapie hyperbare pour toutes les femmes enceintes, le plus rapidement possible et quelque soit l’âge gestationnel. PMID:26405502

Entropy-based consensus clustering for patient stratification.

PubMed

Liu, Hongfu; Zhao, Rui; Fang, Hongsheng; Cheng, Feixiong; Fu, Yun; Liu, Yang-Yu

2017-09-01

Patient stratification or disease subtyping is crucial for precision medicine and personalized treatment of complex diseases. The increasing availability of high-throughput molecular data provides a great opportunity for patient stratification. Many clustering methods have been employed to tackle this problem in a purely data-driven manner. Yet, existing methods leveraging high-throughput molecular data often suffers from various limitations, e.g. noise, data heterogeneity, high dimensionality or poor interpretability. Here we introduced an Entropy-based Consensus Clustering (ECC) method that overcomes those limitations all together. Our ECC method employs an entropy-based utility function to fuse many basic partitions to a consensus one that agrees with the basic ones as much as possible. Maximizing the utility function in ECC has a much more meaningful interpretation than any other consensus clustering methods. Moreover, we exactly map the complex utility maximization problem to the classic K -means clustering problem, which can then be efficiently solved with linear time and space complexity. Our ECC method can also naturally integrate multiple molecular data types measured from the same set of subjects, and easily handle missing values without any imputation. We applied ECC to 110 synthetic and 48 real datasets, including 35 cancer gene expression benchmark datasets and 13 cancer types with four molecular data types from The Cancer Genome Atlas. We found that ECC shows superior performance against existing clustering methods. Our results clearly demonstrate the power of ECC in clinically relevant patient stratification. The Matlab package is available at http://scholar.harvard.edu/yyl/ecc . yunfu@ece.neu.edu or yyl@channing.harvard.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Stratification and salt-wedge in the Seomjin river estuary under the idealized tidal influence

NASA Astrophysics Data System (ADS)

Hwang, Jin Hwan; Jang, Dongmin; Kim, Yong Hoon

2017-12-01

Advection, straining, and vertical mixing play primary roles in the process of estuarine stratification. Estuaries can be classified as salt-wedge, partially-mixed or well-mixed depending on the vertical density structure determined by the balancing of advection, mixing and straining. In particular, straining plays a major role in the stratification of the estuarine water body along the estuarine channel. Also, the behavior of a salt wedge with a halocline shape in a stratified channel can be controlled by the competition between straining and mixing induced by buoyancy from the riverine source and tidal forcing. The present study uses Finite Volume Coastal Ocean Model (FVCOM) to show that straining and vertical mixing play major roles in controlling along-channel flow and stratification structures in the Seomjin river estuary (SRE) under idealized conditions. The Potential Energy Anomaly (PEA) dynamic equation quantifies the governing processes thereby enabling the determination of the stratification type. By comparing terms in the equation, we examined how the relative strengths of straining and mixing alter the stratification types in the SRE due to changes in river discharge and the depth resulting from dredging activities. SRE under idealized tidal forcing tends to be partially-mixed based on an analysis of the balance between terms and the vertical structure of salinity, and the morphological and hydrological change in SRE results in the shift of stratification type. While the depth affects the mixing, the freshwater discharge mainly controls the straining, and the balance between mixing and straining determines the final state of the stratification in an estuarine channel. As a result, the development and location of a salt wedge along the channel in a partially mixed and highly stratified condition is also determined by the ratio of straining to mixing. Finally, our findings confirm that the contributions of mixing and straining can be assessed by using the

Dynamique d'une frontière libre : un siège fascinant de morphogénèse

NASA Astrophysics Data System (ADS)

Misbah, Chaouqi; Müller-Kurmbhaar, Heiner

Un front de solidification, dont le mouvement est limité par une simple diffusion, est le siège d'une myriade de morphogénèses statiques et dynamiques, allant d'une dendrite aux fractals, et d'un front cellulaire stationnaire au chaos spatio-temporel. Plusieurs de ces caractéristiques sont communes à une vaste liste de systèmes hors équilibre. Même l'organisation spatio-temporelle d'une population d'entités vivantes, telles que les bactéries, présente une forte similarité avec celle d'un front de croissance.

The role of thermal stratification in tidal exchange at the mouth of San Diego Bay

USGS Publications Warehouse

Chadwick, D. B.; Largier, J. L.; Cheng, R.T.; Aubrey, D.G.; Friedrichs, C.T.; Aubrey, D.G.; Friedrichs, C.T.

1996-01-01

We have examined, from an observational viewpoint, the role of thermal stratification in the tidal exchange process at the mouth of San Diego Bay. In this region, we found that both horizontal and vertical exchange processes appear to be active. The vertical exchange in this case was apparently due to the temperature difference between the'bay water and ocean water. We found that the structure of the outflow and the nature of the tidal exchange process both appear to be influenced by thermal stratification. The tidal outflow was found to lift-off tan the bottom during the initial and later stages of the ebb flow when barotropic forcing was weak. During the peak ebb flow, the mouth section was flooded, and the outflow extended to the bottom. As the ebb flow weakened, a period of two-way exchange occurred, with the surface layer flowing seaward, and the deep layer flowing into the bay. The structure of the tidal-residual flow and the residual transport of a measured tracer were strongly influenced by this vertical exchange. Exchange appeared to occur laterally as well, in a manner consistent with the tidal-pumping mechanism described by Stommel and Farmer [1952]. Tidal cycle variations in shear and stratification were characterized by strong vertical shear and breakdown of stratification during the ebb, and weak vertical shear and build-up of stratification on the flood. Evaluation of multiple tidal-cycles from time-series records of flow and temperature indicated that the vertical variations of the flow and stratification observed during the cross-sectional measurements are a general phenomenon during the summer. Together, these observations suggest that thermal stratification can play an important role in regulating the tidal exchange of low-inflow estuaries.

Vibrations et relaxations dans les molécules biologiques. Apports de la diffusion incohérente inélastique de neutrons

NASA Astrophysics Data System (ADS)

Zanotti, J.-M.

2005-11-01

Le présent document ne se veut pas un article de revue mais plutôt un élément d'initiation à une technique encore marginale en Biologie. Le lecteur est supposé être un non spécialiste de la diffusion de neutrons poursuivant une thématique à connotation biologique ou biophysique mettant en jeu des phénomènes dynamiques. En raison de la forte section de diffusion incohérente de l'atome d'hydrogène et de l'abondance de cet élément dans les protéines, la diffusion incohérente inélastique de neutrons est une technique irremplaçable pour sonder la dynamique interne des macromolécules biologiques. Après un rappel succinct des éléments théoriques de base, nous décrivons le fonctionnement de différents types de spectromètres inélastiques par temps de vol sur source continue ou pulsée et discutons leurs mérites respectifs. Les deux alternatives utilisées pour décrire la dynamique des protéines sont abordées: (i)l'une en termes de physique statistique, issue de la physique des verres, (ii) la seconde est une interprétation mécanistique. Nous montrons dans ce cas, comment mettre à profit les complémentarités de domaines en vecteur de diffusion et de résolution en énergie de différents spectromètres inélastiques de neutrons (temps de vol, backscattering et spin-écho) pour accéder, à l'aide d'un modèle physique simple, à la dynamique des protéines sur une échelle de temps allant d'une fraction de picoseconde à quelques nanosecondes.

On electron bunching and stratification of glow discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golubovskii, Yuri B.; Kolobov, Vladimir I.; Nekuchaev, Vladimir O.

2013-10-15

Plasma stratification and excitation of ionization waves is one of the fundamental problems in gas discharge physics. Significant progress in this field is associated with the name of Lev Tsendin. He advocated the need for the kinetic approach to this problem contrary to the traditional hydrodynamic approach, introduced the idea of electron bunching in spatially periodic electric fields, and developed a theory of kinetic resonances for analysis of moving striations in rare gases. The present paper shows how Tsendin's ideas have been further developed and applied for understanding the nature of the well-known S-, P-, and R-striations observed in glowmore » discharges of inert gases at low pressures and currents. We review numerical solutions of a Fokker-Planck kinetic equation in spatially periodic electric fields under the effects of elastic and inelastic collisions of electrons with atoms. We illustrate the formation of kinetic resonances at specific field periods for different shapes of injected Electron Distribution Functions (EDF). Computer simulations illustrate how self-organization of the EDFs occurs under nonlocal conditions and how Gaussian-like peaks moving along resonance trajectories are formed in a certain range of discharge conditions. The calculated EDFs agree well with the experimentally measured EDFs for the S, P, and R striations in noble gases. We discuss how kinetic resonances affect dispersion characteristics of moving striations and mention some non-linear effects associated with glow discharge stratification. We propose further studies of stratification phenomena combining physical kinetics and non-linear physics.« less

Vertical Stratification Engineering for Organic Bulk-Heterojunction Devices.

PubMed

Huang, Liqiang; Wang, Gang; Zhou, Weihua; Fu, Boyi; Cheng, Xiaofang; Zhang, Lifu; Yuan, Zhibo; Xiong, Sixing; Zhang, Lin; Xie, Yuanpeng; Zhang, Andong; Zhang, Youdi; Ma, Wei; Li, Weiwei; Zhou, Yinhua; Reichmanis, Elsa; Chen, Yiwang

2018-05-22

High-efficiency organic solar cells (OSCs) can be produced through optimization of component molecular design, coupled with interfacial engineering and control of active layer morphology. However, vertical stratification of the bulk-heterojunction (BHJ), a spontaneous activity that occurs during the drying process, remains an intricate problem yet to be solved. Routes toward regulating the vertical separation profile and evaluating the effects on the final device should be explored to further enhance the performance of OSCs. Herein, we establish a connection between the material surface energy, absorption, and vertical stratification, which can then be linked to photovoltaic conversion characteristics. Through assessing the performance of temporary, artificial vertically stratified layers created by the sequential casting of the individual components to form a multilayered structure, optimal vertical stratification can be achieved. Adjusting the surface energy offset between the substrate results in donor and acceptor stabilization of that stratified layer. Further, a trade-off between the photocurrent generated in the visible region and the amount of donor or acceptor in close proximity to the electrode was observed. Modification of the substrate surface energy was achieved using self-assembled small molecules (SASM), which, in turn, directly impacted the polymer donor to acceptor ratio at the interface. Using three different donor polymers in conjunction with two alternative acceptors in an inverted organic solar cell architecture, the concentration of polymer donor molecules at the ITO (indium tin oxide)/BHJ interface could be increased relative to the acceptor. Appropriate selection of SASM facilitated a synchronized enhancement in external quantum efficiency and power conversion efficiencies over 10.5%.

Photo stratification improves northwest timber volume estimates.

Treesearch

Colin D. MacLean

1972-01-01

Data from extensive timber inventories of 12 counties in western and central Washington were analyzed to test the relative efficiency of double sampling for stratification as a means of estimating total volume. Photo and field plots, when combined in a stratified sampling design, proved about twice as efficient as simple field sampling. Although some gains were made by...

Reconstruction d’une Carbonisation du Pouce par Lambeau Chinois

PubMed Central

Khales, A.; Achbouk, J.A.; Moussaoui, A.; Belmir, R.; Tourabi, K.; Oufkir, A.; Ihrai, H.

2010-01-01

Summary La main en tant qu’organe majeur de la préhension peut être le siège de brûlures graves qui compromettent sa fonction. Bien qu’elle ne représente que 2% de la surface corporelle la brûlure de la main est grave et difficile à traiter, vu la vulnérabilité et la complexité de son appareil locomoteur. Nous rapportons dans ce travail le cas d’un patient victime d’une carbonisation de la main. Huit mois après le parage et la couverture par lambeau inguinal, le patient bénéficie d’une reconstruction du pouce par lambeau chinois associé à une greffe osseuse. Le résultat s’est avéré satisfaisant. Le lambeau chinois prouve par son apport vasculaire et par sa facilité technique qu’il est un moyen très intéressant dans la reconstruction du pouce - ou des doigts en général - surtout dans un contexte de brûlure. PMID:21991226

Lake Stability and Winter-Spring Transitions: Decoupled Ice Duration and Winter Stratification

NASA Astrophysics Data System (ADS)

Daly, J.; Dana, S.; Neal, B.

2016-12-01

Ice-out is an important historical record demonstrating the impact of warmer air temperatures on lake ice. To better understand regional differences in ice-out trends, to characterize the thermal dynamics of smaller mountain lakes, and to develop baseline data for Maine's high elevations landscapes, sub-hourly water temperatures have been collected in over a dozen of Maine's mountain lakes since 2010. Both surface water and hypolimnion temperature data are recorded year-round, facilitating the determination of ice-in, ice-out, and the duration of winter stratification. The multi-year record from sites across as 250 km transect allows us to compare spatial variability related to lake morphometry and location with inter-annual variability related to local weather. All of the study lakes are large enough to stratify during the summer and mix extensively during the fall. Most years, our data show that the onset of winter stratification is nearly synchronous across the study area and is associated with cold air temperatures. Winter stratification can begin days to weeks before ice-in; the timing of ice-in shows more variability, with both elevation and basin aspect influencing the timing. Ice-out shows both the anticipated spatial and interannual variability; some years there is strong coherence between locations while other years show high variability, possibly a function of differences in snowpack. Ice-out is not always immediately followed by the end of winter stratification, there is sometimes a lag of days to weeks before the lakes mix. If the warm temperatures that lead to ice-out are followed by calm days without significant wind, the surface of some lakes begins to warm quickly maintaining the density difference and prolonging winter stratification. The longer the lag time, the stronger the density difference becomes which may also result in a very brief period of mixing in the spring prior to set-up of summer stratification. This year's El Niño event resulted

La neurobrucellose: une cause curable de surdité neurosensorielle à ne pas méconnaitre

PubMed Central

Malhi, Alae Bezzari; Ridal, Mohamed; Bouchal, Siham; Belahsen, Mohammed Faouzi; El Alami, Mohamed-Nourdine

2015-01-01

La brucellose est une zoonose ubiquitaire touchant en particulier les pays méditerranéens et le Moyen-Orient. Les manifestations neurologiques sont assez diverses. Nous rapportons l'observation d'un patient âgé de 45 ans, agriculteur, ayant consulté pour une surdité profonde bilatérale depuis 2 mois associée à des céphalées, des épisodes d'hémiparésie à bascule, de trouble de langage, spontanément résolutifs en quelques minutes et des sensations vertigineuses intermittentes depuis 09 mois. Les résultats de la ponction lombaire, de l'imagerie par résonnance magnétique et surtout la sérologie ont permis de conclure à une neurobrucellose. L’évolution sous bi-antibiothérapie a été favorable, avec régression des signes neurologiques, normalisation du LCR et amélioration de la surdité. La neurobrucellose est une affection grave dont le pronostic dépend de la précocité du diagnostic et du traitement. Nous pensons qu'un tableau clinique associant une surdité neurosensorielle et une symptomatologie neurologique progressive doit évoquer en premier une neurobrucellose, d'autant plus que le patient est à risque et dans les pays où cette maladie est endémique. PMID:26889303

Une recension des écrits concernant la réalité psychoaffective des femmes ayant une vulvodynie : Difficultés rencontrées et stratégies développées

PubMed Central

Cantin-Drouin, Maude; Damant, Dominique; Turcotte, Daniel

2008-01-01

HISTORIQUE : Au cours des trois dernières décennies, une attention grandissante a été portée à l’étude du syndrome de vulvodynie, soit un inconfort vulvaire chronique inexpliqué, éprouvé en l’absence de pathologie précisée. En plus d’avoir des répercussions physiques, l’expérience de la vulvodynie comporte une dimension psychosociale. OBJECTIF : Cet article vise à faire une recension des écrits sur la réalité psychoaffective des femmes qui éprouvent une vulvodynie. MÉTHODE : Une recherche documentaire basée sur une exploration systématique de textes présentant des résultats de recherche et recensés dans les principales banques de données en sciences sociales, dont Dissertation Abstracts, Current Contents et PsycINFO, a été réalisée. RÉSULTATS : Cette recension des écrits révèle, malgré la présence de certains résultats divergents, que les femmes ayant une vulvodynie affrontent souvent des difficultés identitaires et psychologiques, qui sont influencées notamment par les normes sociales de sexualité et de féminité. Pour composer avec ces difficultés, les femmes développent différentes stratégies visant à diminuer le stress occasionné par la douleur et à améliorer leur bien-être psychologique. CONCLUSION : Les difficultés relationnelles et psychologiques vécues par les femmes ayant une vulvodynie ne découlent pas seulement de la douleur physique, mais aussi du sens qu’elles lui accordent, souvent influencé par les discours sociaux sur l’hétérosexualité et la féminité. Il importe donc d’intervenir auprès des femmes en tenant compte de l’influence du contexte social tout en poursuivant le développement des connaissances sur les aspects psychosociaux de cette expérience. PMID:18592063

Une complication exceptionnelle du tétanos généralisé: l’embolie pulmonaire

PubMed Central

Regaieg, Kais; Bahloul, Mabrouk; Gargouri, Rahma; Bouattour, Abir; Chelly, Hèdi; Bouaziz, Mounir

2016-01-01

Le tétanos est une maladie caractérisée par une paralysie spastique et des spasmes. C’est une pathologie grave. Elle nécessite une prise en charge en milieu de réanimation. La mortalité est essentiellement liée aux complications neurovégétatives et infectieuses. Les complications thromboemboliques sont exceptionnelles au cours de cette maladie. A notre connaissance, l’embolie pulmonaire n’a jamais été rapportée et confirmée au cours du tétanos généralisé. Nous présentons à travers cette observation un cas de tétanos généralisé compliqué d’une embolie pulmonaire fibrino cruorique. PMID:28292134

Tidal asymmetries of velocity and stratification over a bathymetric depression in a tropical inlet

NASA Astrophysics Data System (ADS)

Waterhouse, Amy F.; Valle-Levinson, Arnoldo; Morales Pérez, Rubén A.

2012-10-01

Observations of current velocity, sea surface elevation and vertical profiles of density were obtained in a tropical inlet to determine the effect of a bathymetric depression (hollow) on the tidal flows. Surveys measuring velocity profiles were conducted over a diurnal tidal cycle with mixed spring tides during dry and wet seasons. Depth-averaged tidal velocities during ebb and flood tides behaved according to Bernoulli dynamics, as expected. The dynamic balance of depth-averaged quantities in the along-channel direction was governed by along-channel advection and pressure gradients with baroclinic pressure gradients only being important during the wet season. The vertical structure of the along-channel flow during flood tides exhibited a mid-depth maximum with lateral shear enhanced during the dry season as a result of decreased vertical stratification. During ebb tides, along-channel velocities in the vicinity of the hollow were vertically sheared with a weak return flow at depth due to choking of the flow on the seaward slope of the hollow. The potential energy anomaly, a measure of the amount of energy required to fully mix the water column, showed two peaks in stratification associated with ebb tide and a third peak occurring at the beginning of flood. After the first mid-ebb peak in stratification, ebb flows were constricted on the seaward slope of the hollow resulting in a bottom return flow. The sinking of surface waters and enhanced mixing on the seaward slope of the hollow reduced the potential energy anomaly after maximum ebb. The third peak in stratification during early flood occurred as a result of denser water entering the inlet at mid-depth. This dense water mixed with ambient deep waters increasing the stratification. Lateral shear in the along-channel flow across the hollow allowed trapping of less dense water in the surface layers further increasing stratification.

Influence of Lake Stratification Onset on Summer Surface Water Temperature

NASA Astrophysics Data System (ADS)

Woolway, R. I.; Merchant, C. J.

2016-12-01

Summer lake surface water temperatures (LSSWT) are sensitive to climatic warming and have previously been shown to increase at a faster rate than surface air temperatures in some lakes, as a response to thermal stratification occurring earlier in spring. We explore this relationship using a combination of in situ, satellite derived, and simulated temperatures from 144 lakes. Our results demonstrate that LSSWTs of high-latitude and large deep lakes are particularly sensitive to changes in stratification onset and can be expected to display an amplified response to climatic changes in summer air temperature. Climatic modification of LSSWT has numerous consequences for water quality and lake ecosystems, so quantifying this amplified response is important.

Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer

DTIC Science & Technology

2017-10-01

SUPPLEMENTARY NOTES 14. ABSTRACT Prostate cancer (PCA) is a clinically and genetically heterogeneous and the development of a molecular classification is...AWARD NUMBER: W81XWH-16-1-0739 TITLE: Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer PRINCIPAL...AND SUBTITLE 5a. CONTRACT NUMBER Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer 5b. GRANT NUMBER W81XWH

Improving the Power of GWAS and Avoiding Confounding from Population Stratification with PC-Select

PubMed Central

Tucker, George; Price, Alkes L.; Berger, Bonnie

2014-01-01

Using a reduced subset of SNPs in a linear mixed model can improve power for genome-wide association studies, yet this can result in insufficient correction for population stratification. We propose a hybrid approach using principal components that does not inflate statistics in the presence of population stratification and improves power over standard linear mixed models. PMID:24788602

Ion species stratification within strong shocks in two-ion plasmas

NASA Astrophysics Data System (ADS)

Keenan, Brett D.; Simakov, Andrei N.; Taitano, William T.; Chacón, Luis

2018-03-01

Strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al., Phys. Rev. E 96, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by the Mach number, M. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification and temperature separation). These are important effects since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likely contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with the arbitrary Mach number and the relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Additionally, we find that the shock fronts are enriched with the lighter ion species and the enrichment scales as M4 for M ≫ 1.

Sensitivity of Rogue Waves Predictions to the Oceanic Stratification

NASA Astrophysics Data System (ADS)

Guo, Qiuchen; Alam, Mohammad-Reza

2014-11-01

Oceanic rogue waves are short-lived very large amplitude waves (a giant crest typically followed or preceded by a deep trough) that appear and disappear suddenly in the ocean causing damages to ships and offshore structures. Assuming that the state of the ocean at the present time is perfectly known, then the upcoming rogue waves can be predicted via numerically solving the equations that govern the evolution of the waves. The state of the art radar technology can now provide accurate wave height measurement over large spatial domains and when combined with advanced wave-field reconstruction techniques together render deterministic details of the current state of the ocean (i.e. surface elevation and velocity field) at any given moment of the time with a very high accuracy. The ocean water density is, however, stratified (mainly due to the salinity and temperature differences). This density stratification, with today's technology, is very difficult to be measured accurately. As a result in most predictive schemes these density variations are neglected. While the overall effect of the stratification on the average state of the ocean may not be significant, here we show that these density variations can strongly affect the prediction of oceanic rogue waves. Specifically, we consider a broadband oceanic spectrum in a two-layer density stratified fluid, and study via extensive statistical analysis the effects of strength of the stratification (difference between densities) and the depth of the thermocline on the prediction of upcoming rogue waves.

Impact on Water Heater Performance of Heating Methods that Promote Tank Temperature Stratification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gluesenkamp, Kyle R; BushPE, John D

2016-01-01

During heating of a water heater tank, the vertical temperature stratification of the water can be increased or decreased, depending on the method of heating. Methods that increase stratification during heating include (1) removing cold water from the tank bottom, heating it, and re-introducing it to the tank top at relatively low flow rate, (2) using a heat exchanger wrapped around the tank, through which heating fluid (with finite specific heat) flows from top to bottom, and (3) using an immersed heat element that is relatively high in the tank. Using such methods allows for improved heat pump water heatermore » (HPWH) cycle efficiencies when the heat pump can take advantage of the lower temperatures that exist lower in the tank, and accommodate the resulting glide. Transcritical cycles are especially well-suited to capitalize on this opportunity, and other HPWH configurations (that have been proposed elsewhere) may benefit as well. This work provides several stratification categories of heat pump water heater tank configurations relevant to their stratification potential. To illustrate key differences among categories, it also compiles available experimental data for (a) single pass pumped flow, (b) multi-pass pumped flow, and (c) top-down wrapped tank with transcritical refrigerant.« less

Seed flotation and germination of salt marsh plants: The effects of stratification, salinity, and/or inundation regime

USGS Publications Warehouse

Elsey-Quirk, T.; Middleton, B.A.; Proffitt, C.E.

2009-01-01

We examined the effects of cold stratification and salinity on seed flotation of eight salt marsh species. Four of the eight species were tested for germination success under different stratification, salinity, and flooding conditions. Species were separated into two groups, four species received wet stratification and four dry stratification and fresh seeds of all species were tested for flotation and germination. Fresh seeds of seven out of eight species had flotation times independent of salinity, six of which had average flotation times of at least 50 d. Seeds of Spartina alterniflora and Spartina patens had the shortest flotation times, averaging 24 and 26 d, respectively. Following wet stratification, the flotation time of S. alterniflora seeds in higher salinity water (15 and 36 ppt) was reduced by over 75% and germination declined by more than 90%. Wet stratification reduced the flotation time of Distichlis spicata seeds in fresh water but increased seed germination from 2 to 16% in a fluctuating inundation regime. Fresh seeds of Iva frutescens and S. alternflora were capable of germination and therefore are non-dormant during dispersal. Fresh seeds of I. frutescens had similar germination to dry stratified seeds ranging 25-30%. Salinity reduced seed germination for all species except for S. alterniflora. A fluctuating inundation regime was important for seed germination of the low marsh species and for germination following cold stratification. The conditions that resulted in seeds sinking faster were similar to the conditions that resulted in higher germination for two of four species. ?? 2009 Elsevier B.V.

Soins primaires aux adultes ayant une déficience développementale

PubMed Central

Sullivan, William F.; Berg, Joseph M.; Bradley, Elspeth; Cheetham, Tom; Denton, Richard; Heng, John; Hennen, Brian; Joyce, David; Kelly, Maureen; Korossy, Marika; Lunsky, Yona; McMillan, Shirley

2011-01-01

Résumé Objectif Mettre à jour les lignes directrices canadiennes de 2006 sur les soins primaires aux adultes ayant une déficience développementale (DD) et présenter des recommandations pratiques fondées sur les connaissances actuelles pour traiter des problèmes de santé particuliers chez des adultes ayant une DD. Qualité des preuves Des professionnels de la santé expérimentés participant à un colloque et un groupe de travail subséquent ont discuté et convenu des révisions aux lignes directrices de 2006 en se fondant sur une recherche documentaire exhaustive, la rétroaction obtenue des utilisateurs du guide de pratique et les expériences cliniques personnelles. La plupart des preuves disponibles dans ce domaine viennent de l’opinion d’experts ou de déclarations consensuelles publiées (niveau III). Message principal Les adultes ayant une DD ont des problèmes de santé complexes, dont plusieurs diffèrent de ceux de la population en général. De bons soins primaires permettent d’identifier les problèmes de santé particuliers dont souffrent les adultes ayant une DD pour améliorer leur qualité de vie et leur accès aux soins de santé et prévenir la morbidité et le décès prématuré. Ces lignes directrices résument les problèmes de santé générale, physique, comportementale et mentale des adultes ayant une DD que devraient connaître les professionnels des soins primaires et présentent des recommandations pour le dépistage et la prise en charge en se basant sur les connaissances actuelles que les cliniciens peuvent mettre en pratique. En raison de l’interaction des facteurs biologiques, psychoaffectifs et sociaux qui contribuent à la santé et au bien-être des adultes ayant une DD, ces lignes directrices insistent sur la participation des aidants, l’adaptation des interventions, au besoin, et la consultation auprès de divers professionnels de la santé quand ils sont accessibles. Elles mettent aussi en évidence la

Overheating instability of a thin conductor with respect to stratification

NASA Astrophysics Data System (ADS)

Garanin, S. F.; Kuznetsov, S. D.

2018-04-01

We consider an overheating instability of a thin (compared to the skin depth) conductor with respect to stratification at the stage when its resistivity rises up to an electrical explosion. Temperature perturbations under such conditions are shown to grow in proportion to resistivity. In the model, when resistivity is proportional to temperature, perturbations grow in proportion to temperature and hence exhibit no relative growth. For a conductor with initial thickness perturbations, temperature perturbations grow in proportion to resistivity and current action integral, i.e., somewhat faster than perturbations in the problem of constant thickness conductors. Comparison of our results with simulations of the growth of stratification during electrical heating of foils in warm dense matter generation systems demonstrates their close agreement.

Schwannome benin primitif retrovesical: une tumeur très rare à propos d'un cas

PubMed Central

Beddouche, Ali; Fahsi, Othemane; Kallat, Adil; El Bote, Hicham; Ziani, Idriss; El Sayegh, Hachem; Iken, Ali; Benslimane, Lounis; Nouini, Yassine

2016-01-01

Le schwannome est une tumeur le plus souvent bénigne, d'origine nerveuse se développant à partir des cellules de la gaine de Schwann. C'est une tumeur très rare tant par sa fréquence que par sa localisation rétrovésicale. L'examen anatomopathologique et immunohistochimique confirme le type histologique ainsi que le caractère bénin ou malin du schwannome. En raison des récidives, et du risque de transformation maligne, l'exérèse doit être complète. Nous rapportons le cas d'un patient âgé de 39 ans, admis pour une douleur pelvienne chronique à type de pesanteur, des signes irritatifs du bas appareil urinaire, et des troubles de transit. L'imagerie (échographie, TDM, IRM) a révélé la présence d'une masse pelvienne rétrovésicale, à paroi fine, latéralisée à gauche, mesurant 68x70x70 mm, exerçant un effet de masse sur la vessie et le sigmoïde. L'intervention chirurgicale menée par une laparotomie médiane a permis l'exérèse d'une masse retrovésicale bien encapsulée. L'examen anatomopathologique et immunohistochimique ont conclu à un schwannome bénin. La récidive et la transformation maligne bien que rare après chirurgie impose une surveillance post opératoire clinique et tomodensitométrique annuelle. PMID:27217902

Germination of dimorphic seeds of Suaeda aralocaspica in response to light and salinity conditions during and after cold stratification

PubMed Central

Wang, Hong-Ling; Tian, Chang-Yan

2017-01-01

Cold stratification is a requirement for seed dormancy breaking in many species, and thus it is one of the important factors for the regulation of timing of germination. However, few studies have examined the influence of various environmental conditions during cold stratification on subsequent germination, and no study has compared such effects on the performance of dormant versus non-dormant seeds. Seeds of halophytes in the cold desert might experience different light and salinity conditions during and after cold stratification. As such, dimorphic seeds (non-dormant brown seeds and black seeds with non-deep physiological dormancy) of Suaeda aralocaspica were cold stratified under different light (12 h light–12 h darkness photoperiod or continuous darkness) or salinity (0, 200 or 1,000 mmol L-1 NaCl) conditions for 20 or 40 days. Then stratified seeds were incubated under different light or salinity conditions at daily (12/12 h) temperature regime of 10:25 °C for 20 days. For brown seeds, cold stratification was also part of the germination period. In contrast, almost no black seeds germinated during cold stratification. The longer the cold stratification, the better the subsequent germination of black seeds, regardless of light or salinity conditions. Light did not influence germination of brown seeds. Germination of cold-stratified black seeds was inhibited by darkness, especially when they were stratified in darkness. With an increase in salinity at the stage of cold stratification or germination, germination percentages of both seed morphs decreased. Combinational pre-treatments of cold stratification and salinity did not increase salt tolerance of dimorphic seeds in germination phase. Thus, light and salinity conditions during cold stratification partly interact with these conditions during germination stage and differentially affect germination of dimorphic seeds of S. aralocaspica. PMID:28828266

Cardiomyopathie du péripartum: à propos d’une observation et revue de la littérature

PubMed Central

Bouzerda, Abdelmajid

2016-01-01

La cardiomyopathie du péripartum ou cardiomyopathie gravidique primitive, est une entité rare et méconnue définie comme une insuffisance cardiaque systolique survenant le dernier mois de la grossesse ou les cinq premiers mois du postpartum en l'absence d'étiologie connue ou de cardiopathie préexistante. Nous rapportons l'observation d'une jeune patiente de 31 ans sans antécédents pathologiques particuliers admise pour une poussée d'insuffisance cardiaque gauche 1mois après son accouchement. Le contexte de péripartum nous a fait penser au diagnostic et a motivé la réalisation d'une Echocardiographie qui a confirmé cette entité. PMID:28154713

An efficient modeling method for thermal stratification simulation in a BWR suppression pool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haihua Zhao; Ling Zou; Hongbin Zhang

2012-09-01

The suppression pool in a BWR plant not only is the major heat sink within the containment system, but also provides major emergency cooling water for the reactor core. In several accident scenarios, such as LOCA and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; and the pool temperature distribution also affects the NPSHa (Available Net Positive Suction Head) and therefore the performance of the pump which draws cooling water back to the core. Current safetymore » analysis codes use 0-D lumped parameter methods to calculate the energy and mass balance in the pool and therefore have large uncertainty in prediction of scenarios in which stratification and mixing are important. While 3-D CFD methods can be used to analyze realistic 3D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, therefore long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by 1-D transient partial differential equations and substructures such as free or wall jets are modeled with 1-D integral models. This allows very large reductions in computational effort compared to 3-D CFD modeling. The POOLEX experiments at Finland, which was designed to study phenomena relevant to Nordic design BWR suppression pool including thermal stratification and mixing, are used for validation. GOTHIC lumped parameter models are used to obtain boundary conditions for BMIX++ code and CFD simulations. Comparison between the BMIX++, GOTHIC, and CFD calculations against the POOLEX experimental data is discussed in detail.« less

The Social Stratification of the German VET System

ERIC Educational Resources Information Center

Protsch, Paula; Solga, Heike

2016-01-01

Germany is widely known for its vocational education and training (VET) system and its dual apprenticeship system in particular. What is often overlooked, however, is the vertical stratification within the German VET system. This is the focus of this study. Our analysis shows that the VET system, like the German school system, is highly…

Ion species stratification within strong shocks in two-ion plasmas

DOE PAGES

Keenan, Brett D.; Simakov, Andrei N.; Taitano, William T.; ...

2018-03-01

We report strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al., Phys. Rev. E 96, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by the Mach number, M. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification and temperature separation). These are important effects since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likelymore » contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with the arbitrary Mach number and the relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Lastly, we find that the shock fronts are enriched with the lighter ion species and the enrichment scales as M 4 for M»1.« less

Ion species stratification within strong shocks in two-ion plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keenan, Brett D.; Simakov, Andrei N.; Taitano, William T.

We report strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al., Phys. Rev. E 96, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by the Mach number, M. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification and temperature separation). These are important effects since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likelymore » contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with the arbitrary Mach number and the relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Lastly, we find that the shock fronts are enriched with the lighter ion species and the enrichment scales as M 4 for M»1.« less

Preablation 131-I scans with SPECT/CT contribute to thyroid cancer risk stratification and 131-I therapy planning.

PubMed

Avram, Anca M; Esfandiari, Nazanene H; Wong, Ka Kit

2015-05-01

The use of preablation diagnostic radioiodine scans for risk stratification and radioiodine therapy planning for differentiated thyroid cancer (DTC) remains controversial. The objective was to assess the contribution of preablation diagnostic 131-I scans with SPECT/CT (Dx 131-I scan) to (1) the risk stratification and (2) the postoperative management of DTC. The study was designed as a prospective sequential patient series. The study was conducted at a University hospital. Three hundred twenty patients (pts) with DTC (219F; 101M, mean age 47.3 ± 16.4 y, range 10-90) were studied. Using clinical and histopathology information an endocrinologist performed risk stratification and determined postoperative management with respect to radioiodine therapy (RAI) planning. The decision to withhold or to administer RAI, and the recommended low, medium or high therapeutic 131-I activity were recorded. Dx 131-I scans were performed and interpreted by two nuclear medicine physicians as showing thyroid remnant, cervical nodal, or distant metastases. The endocrinologist then reperformed risk stratification and reformulated management after consideration of Dx 131-I scans and stimulated thyroglobulin (Tg) information. Main outcome measures were changes in risk stratification and management after Dx 131-I scans. Detection of unsuspected nodal and distant metastases and elevated stimulated Tg levels resulted in a change in the estimated risk of recurrence in 15% of patients, and management in 31% of patients, as compared to initial risk stratification and management based on histopathology alone. Both imaging data and stimulated thyroglobulin levels acquired at the time of Dx 131-I scans are consequential for 131-I therapy planning, providing information that changes risk stratification in 15% of patients as compared to recurrence risk estimation based on histopathology alone. Dx 131-I scans contribute to risk stratification by defining residual nodal and distant metastatic disease

Deep circulations under simple classes of stratification

NASA Technical Reports Server (NTRS)

Salby, Murry L.

1989-01-01

Deep circulations where the motion field is vertically aligned over one or more scale heights are studied under barotropic and equivalent barotropic stratifications. The study uses two-dimensional equations reduced from the three-dimensional primitive equations in spherical geometry. A mapping is established between the full primitive equations and general shallow water behavior and the correspondence between variables describing deep atmospheric motion and those of shallow water behavior is established.

Processus ultra-rapides associés à la dynamique d'émission de la protéine GFP

NASA Astrophysics Data System (ADS)

Didier, P.; Guidoni, L.; Schwalbach, G.; Bigot, J.-Y.

2002-06-01

La protéine GFP (Green Fluorescent Protein) est un marqueur très efficace, utilisable en milieu vivant. La spectroscopie femtoseconde est particulièrement bien adaptée pour comprendre les mécanismes d'émission de cette protéine, étant donné la rapidité des processus de transfert mis en jeu. Nous-présentons des résultats sur la dynamique spectro-temporelle d'émission du mutant GFPuv résolue à l'échelle de la centaine de femtosecondes. Une transition Raman à 3300 cm^{-1} ainsi que la dynamique d'etablissement du gain avec un temps caractéristique d'environ 1.5 ps ont été mis en évidence.

Déshumidification de l'air d'une serre par contact direct à courants croisés avec une solution hygroscopique organique

NASA Astrophysics Data System (ADS)

Chraibi, A.; Jaffrin, A.; Makhlouf, S.; Bentounes, N.

1995-07-01

Greenhouse air can be dehumidified by direct contact with a desicant fluid on a trickle exchanger. The water vapour extraction rate depends on the hygroscopicity of the fluid and on the exchanger efficiency. An organic fluid, the triethylene glycol (TEG) at 90% concentration, has been tested. Cross corrugated cellulosic pads, of the type used in cooling, irrigated with TEG, were placed in a wind channel to dehumidify air at various speeds and temperatures. A semi-analytical model, based on energy and mass conservation, correctly reproduces the water vapor extraction rate and the enthalpy change of both fluids. It is shown that TEG trickling through a ventilated pad of 1 m^2 area and 0.1 m thickness can be used to extract 3 to 5 kg of water vapor per hour in greenhouse climate control applications. Several pads arranged in series can be used to decrease more efficiently the absolute humidity of the air, for other applications like food drying or industrial compressed air. Une technique de déshumidification de l'air des serres consiste à le soumettre au contact d'une solution hygroscopique au sein d'un échangeur ruisselant. Le taux d'extraction de vapeur d'eau dépend à la fois du pouvoir hygroscopique de la solution et de l'efficacité de l'échangeur. Une solution hygroscopique organique, le triéthylène glycol à 90% de concentration, a été expérimentée. Un échangeur ruisselant constitué de parois de cellulose ondulées à corrugations croisées, du type “cooling pad” pour serres agricoles, a été testé pour déshumidifier de l'air dans une soufflerie expérimentale. Un modèle semi-analytique, basé sur les équations de conservation de l'énergie et de masse, permet de rendre compte des échanges et de déduire les paramètres de sortie des deux fluides en contact, à partir des caractéristiques d'entrée. Cette étude permet de chiffrer à environ 3 à 5kg/h la capacité de déshumidification d'un panneau d'un mètre carré et de 10cm d

Effects of enhanced stratification on equatorward dynamo wave propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Käpylä, Petri J.; Mantere, Maarit J.; Cole, Elizabeth

We present results from simulations of rotating magnetized turbulent convection in spherical wedge geometry representing parts of the latitudinal and longitudinal extents of a star. Here we consider a set of runs for which the density stratification is varied, keeping the Reynolds and Coriolis numbers at similar values. In the case of weak stratification, we find quasi-steady dynamo solutions for moderate rotation and oscillatory ones with poleward migration of activity belts for more rapid rotation. For stronger stratification, the growth rate tends to become smaller. Furthermore, a transition from quasi-steady to oscillatory dynamos is found as the Coriolis number ismore » increased, but now there is an equatorward migrating branch near the equator. The breakpoint where this happens corresponds to a rotation rate that is about three to seven times the solar value. The phase relation of the magnetic field is such that the toroidal field lags behind the radial field by about π/2, which can be explained by an oscillatory α{sup 2} dynamo caused by the sign change of the α-effect about the equator. We test the domain size dependence of our results for a rapidly rotating run with equatorward migration by varying the longitudinal extent of our wedge. The energy of the axisymmetric mean magnetic field decreases as the domain size increases and we find that an m = 1 mode is excited for a full 2π azimuthal extent, reminiscent of the field configurations deduced from observations of rapidly rotating late-type stars.« less

Une nouvelle voie pour la conception des implants intervertébraux

NASA Astrophysics Data System (ADS)

Gradel, T.; Tabourot, L.; Arrieux, R.; Balland, P.

2002-12-01

L'objectif de notre travail est la conception d'une nouvelle génération d'implants intersomatiques qui s'adapte parfaitement à la géométrie des plateaux vertébraux en se déformant. Pour cela, nous avons utilisé une nouvelle démarche qui consiste à simuler entièrement le procédé de fabrication en l'occurrence l'emboutissage, Cette simulation, en concervant l'historique des sollicitations exercées sur le matériau lors de sa mise en œuvre permet de valider très précisément sa résistance mécanique en fin de cycle. Au cours de cette étude, nous avons mené en parallèle deux analyses dites “ coopératives ” : l'une fondée sur un modèle phénoménologique de type HILL et l'autre sur un modèle multi-échelles prenant en compte des phénomènes plus physiques afin d'acquérir une bonne connaissance du comportement du matériau lors de la déformation. C'est pour sa bonne résistance, sa biocompatibilité et ses propriétés radiologiques que nous avons choisi le T40 (titane pur) comme matériau.

The effect of stratification on premixed swirl-flame flashback by using porous center-body injection

NASA Astrophysics Data System (ADS)

McCaslin, Andrew; Ranjan, Rakesh; Clemens, Noel

2016-11-01

Boundary layer flashback must be prevented in order to stably operate stationary gas turbines. One strategy to avoid flashback is to create equivalence-ratio stratification, such as by reducing the fuel/air ratio in the boundary layer below the flammability limit. Typically, stratification is achieved by using radially non-uniform fuel injection. The goal of the current study is to reduce the propensity of flashback in a premixed annular swirl combustor that uses a premix section with center-body. A porous metal center-body (10 micron pore size) is used to bleed air directly into the boundary layer and thus locally reduce the equivalence ratio. Planar laser-induced fluorescence imaging of anisole-seeded flow is carried out to assess the stratification in the flow. Time-resolved PIV and chemiluminescence imaging are used to investigate flashback at atmospheric pressure conditions. A comparative study between fully premixed and stratified flame flashback is conducted to determine how stratification influences flashback physics. This work was sponsored by the DOE NETL under Grant DEFC2611-FE0007107. This source of funding is gratefully acknowledged.

Classification accuracy for stratification with remotely sensed data

Treesearch

Raymond L. Czaplewski; Paul L. Patterson

2003-01-01

Tools are developed that help specify the classification accuracy required from remotely sensed data. These tools are applied during the planning stage of a sample survey that will use poststratification, prestratification with proportional allocation, or double sampling for stratification. Accuracy standards are developed in terms of an “error matrix,” which is...

Evolution of South Atlantic density and chemical stratification across the last deglaciation

PubMed Central

Skinner, Luke C.; Peck, Victoria L.; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; Hodell, David A.

2016-01-01

Explanations of the glacial–interglacial variations in atmospheric pCO2 invoke a significant role for the deep ocean in the storage of CO2. Deep-ocean density stratification has been proposed as a mechanism to promote the storage of CO2 in the deep ocean during glacial times. A wealth of proxy data supports the presence of a “chemical divide” between intermediate and deep water in the glacial Atlantic Ocean, which indirectly points to an increase in deep-ocean density stratification. However, direct observational evidence of changes in the primary controls of ocean density stratification, i.e., temperature and salinity, remain scarce. Here, we use Mg/Ca-derived seawater temperature and salinity estimates determined from temperature-corrected δ18O measurements on the benthic foraminifer Uvigerina spp. from deep and intermediate water-depth marine sediment cores to reconstruct the changes in density of sub-Antarctic South Atlantic water masses over the last deglaciation (i.e., 22–2 ka before present). We find that a major breakdown in the physical density stratification significantly lags the breakdown of the deep-intermediate chemical divide, as indicated by the chemical tracers of benthic foraminifer δ13C and foraminifer/coral 14C. Our results indicate that chemical destratification likely resulted in the first rise in atmospheric pCO2, whereas the density destratification of the deep South Atlantic lags the second rise in atmospheric pCO2 during the late deglacial period. Our findings emphasize that the physical and chemical destratification of the ocean are not as tightly coupled as generally assumed. PMID:26729858

Evolution of South Atlantic density and chemical stratification across the last deglaciation.

PubMed

Roberts, Jenny; Gottschalk, Julia; Skinner, Luke C; Peck, Victoria L; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; Vázquez Riveiros, Natalia; Hodell, David A

2016-01-19

Explanations of the glacial-interglacial variations in atmospheric pCO2 invoke a significant role for the deep ocean in the storage of CO2. Deep-ocean density stratification has been proposed as a mechanism to promote the storage of CO2 in the deep ocean during glacial times. A wealth of proxy data supports the presence of a "chemical divide" between intermediate and deep water in the glacial Atlantic Ocean, which indirectly points to an increase in deep-ocean density stratification. However, direct observational evidence of changes in the primary controls of ocean density stratification, i.e., temperature and salinity, remain scarce. Here, we use Mg/Ca-derived seawater temperature and salinity estimates determined from temperature-corrected δ(18)O measurements on the benthic foraminifer Uvigerina spp. from deep and intermediate water-depth marine sediment cores to reconstruct the changes in density of sub-Antarctic South Atlantic water masses over the last deglaciation (i.e., 22-2 ka before present). We find that a major breakdown in the physical density stratification significantly lags the breakdown of the deep-intermediate chemical divide, as indicated by the chemical tracers of benthic foraminifer δ(13)C and foraminifer/coral (14)C. Our results indicate that chemical destratification likely resulted in the first rise in atmospheric pCO2, whereas the density destratification of the deep South Atlantic lags the second rise in atmospheric pCO2 during the late deglacial period. Our findings emphasize that the physical and chemical destratification of the ocean are not as tightly coupled as generally assumed.

Fundamental Interactions in Gasoline Compression Ignition Engines with Fuel Stratification

NASA Astrophysics Data System (ADS)

Wolk, Benjamin Matthew

Transportation accounted for 28% of the total U.S. energy demand in 2011, with 93% of U.S. transportation energy coming from petroleum. The large impact of the transportation sector on global climate change necessitates more-efficient, cleaner-burning internal combustion engine operating strategies. One such strategy that has received substantial research attention in the last decade is Homogeneous Charge Compression Ignition (HCCI). Although the efficiency and emissions benefits of HCCI are well established, practical limits on the operating range of HCCI engines have inhibited their application in consumer vehicles. One such limit is at high load, where the pressure rise rate in the combustion chamber becomes excessively large. Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. The aim is to introduce reactivity gradients through fuel stratification to promote sequential auto-ignition rather than a bulk-ignition, as in the homogeneous case. A gasoline-fueled compression ignition engine with fuel stratification is termed a Gasoline Compression Ignition (GCI) engine. Although a reasonable amount of experimental research has been performed for fuel stratification in GCI engines, a clear understanding of how the fundamental in-cylinder processes of fuel spray evaporation, mixing, and heat release contribute to the observed phenomena is lacking. Of particular interest is gasoline's pressure sensitive low-temperature chemistry and how it impacts the sequential auto-ignition of the stratified charge. In order to computationally study GCI with fuel stratification using three-dimensional computational fluid dynamics (CFD) and chemical kinetics, two reduced mechanisms have been developed. The reduced mechanisms were developed from a large, detailed mechanism with about 1400 species for a 4-component gasoline surrogate. The two versions of the reduced mechanism developed in this work are: (1) a 96-species version and (2

Shifts in coastal Antarctic marine microbial communities during and after melt water-related surface stratification.

PubMed

Piquet, Anouk M-T; Bolhuis, Henk; Meredith, Michael P; Buma, Anita G J

2011-06-01

Antarctic coastal waters undergo major physical alterations during summer. Increased temperatures induce sea-ice melting and glacial melt water input, leading to strong stratification of the upper water column. We investigated the composition of micro-eukaryotic and bacterial communities in Ryder Bay, Antarctic Peninsula, during and after summertime melt water stratification, applying community fingerprinting (denaturing gradient gel electrophoresis) and sequencing analysis of partial 18S and 16S rRNA genes. Community fingerprinting of the eukaryotic community revealed two major patterns, coinciding with a period of melt water stratification, followed by a period characterized by regular wind-induced breakdown of surface stratification. During the first stratified period, we observed depth-related differences in eukaryotic fingerprints while differences in bacterial fingerprints were weak. Wind-induced breakdown of the melt water layer caused a shift in the eukaryotic community from an Actinocyclus sp.- to a Thalassiosira sp.-dominated community. In addition, a distinct transition in the bacterial community was found, but with a few days' delay, suggesting a response to the changes in the eukaryotic community rather than to the mixing event itself. Sequence analysis revealed a shift from an Alpha- and Gammaproteobacteria to a Cytophaga-Flavobacterium-Bacteroides-dominated community under mixed conditions. Our results show that melt water stratification and the transition to nonstabilized Antarctic surface waters may have an impact not only on micro-eukaryotic but also bacterial community composition. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Role of Immune Microenvironmental Factors for Improving the IPI-related Risk Stratification of Aggressive B Cell Lymphoma.

PubMed

Gong, Yi; Chen, Rui; Zhang, Xi; Zou, Zhong Min; Chen, Xing Hua

2017-07-01

To investigate the risk stratification of aggressive B cell lymphoma using the immune microenvironment and clinical factors. A total of 127 patients with aggressive B cell lymphoma between 2014 and 2015 were enrolled in this study. CD4, Foxp3, CD8, CD68, CD163, PD-1, and PD-L1 expression levels were evaluated in paraffin-embedded lymphoma tissues to identify their roles in the risk stratification. Eleven factors were identified for further evaluation using analysis of variance, chi-square, and multinomial logistic regression analysis. Significant differences in 11 factors (age, Ann Arbor stage, B symptom, ECOG performance status, infiltrating CD8+ T cells, PD-L1 expression, absolute blood monocyte count, serum lactate dehydrogenase, serum iron, serum albumin, and serum β2-microglobulin) were observed among patient groups stratified by at least two risk stratification methods [International Prognostic Index (IPI), revised IPI, and NCCN-IPI models] (P < 0.05). Concordance rates were high (81.4%-100.0%) when these factors were used for the risk stratification. No difference in the risk stratification results was observed with or without the Ann Arbor stage data. We developed a convenient and inexpensive tool for use in risk stratification of aggressive B cell lymphomas, although further studies on the role of immune microenvironmental factors are needed. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

pyNBS: A Python implementation for network-based stratification of tumor mutations.

PubMed

Huang, Justin K; Jia, Tongqiu; Carlin, Daniel E; Ideker, Trey

2018-03-28

We present pyNBS: a modularized Python 2.7 implementation of the network-based stratification (NBS) algorithm for stratifying tumor somatic mutation profiles into molecularly and clinically relevant subtypes. In addition to release of the software, we benchmark its key parameters and provide a compact cancer reference network that increases the significance of tumor stratification using the NBS algorithm. The structure of the code exposes key steps of the algorithm to foster further collaborative development. The package, along with examples and data, can be downloaded and installed from the URL http://www.github.com/huangger/pyNBS/. jkh013@ucsd.edu.

Introducing Social Stratification and Inequality: An Active Learning Technique.

ERIC Educational Resources Information Center

McCammon, Lucy

1999-01-01

Summarizes literature on techniques for teaching social stratification. Describes the three parts of an exercise that enables students to understand economic and political inequality: students are given a family scenario, create household budgets, and finally rework the national budget with their family scenario groups. Discusses student…

Recommendations on breast cancer screening and prevention in the context of implementing risk stratification: impending changes to current policies

PubMed Central

Gagnon, J.; Lévesque, E.; Borduas, F.; Chiquette, J.; Diorio, C.; Duchesne, N.; Dumais, M.; Eloy, L.; Foulkes, W.; Gervais, N.; Lalonde, L.; L’Espérance, B.; Meterissian, S.; Provencher, L.; Richard, J.; Savard, C.; Trop, I.; Wong, N.; Knoppers, B.M.; Simard, J.

2016-01-01

In recent years, risk stratification has sparked interest as an innovative approach to disease screening and prevention. The approach effectively personalizes individual risk, opening the way to screening and prevention interventions that are adapted to subpopulations. The international perspective project, which is developing risk stratification for breast cancer, aims to support the integration of its screening approach into clinical practice through comprehensive tool-building. Policies and guidelines for risk stratification—unlike those for population screening programs, which are currently well regulated—are still under development. Indeed, the development of guidelines for risk stratification reflects the translational aspects of perspective. Here, we describe the risk stratification process that was devised in the context of perspective, and we then explain the consensus-based method used to develop recommendations for breast cancer screening and prevention in a risk-stratification approach. Lastly, we discuss how the recommendations might affect current screening policies. PMID:28050152

Authorial and institutional stratification in open access publishing: the case of global health research.

PubMed

Siler, Kyle; Haustein, Stefanie; Smith, Elise; Larivière, Vincent; Alperin, Juan Pablo

2018-01-01

Using a database of recent articles published in the field of Global Health research, we examine institutional sources of stratification in publishing access outcomes. Traditionally, the focus on inequality in scientific publishing has focused on prestige hierarchies in established print journals. This project examines stratification in contemporary publishing with a particular focus on subscription vs. various Open Access (OA) publishing options. Findings show that authors working at lower-ranked universities are more likely to publish in closed/paywalled outlets, and less likely to choose outlets that involve some sort of Article Processing Charge (APCs; gold or hybrid OA). We also analyze institutional differences and stratification in the APC costs paid in various journals. Authors affiliated with higher-ranked institutions, as well as hospitals and non-profit organizations pay relatively higher APCs for gold and hybrid OA publications. Results suggest that authors affiliated with high-ranked universities and well-funded institutions tend to have more resources to choose pay options with publishing. Our research suggests new professional hierarchies developing in contemporary publishing, where various OA publishing options are becoming increasingly prominent. Just as there is stratification in institutional representation between different types of publishing access, there is also inequality within access types.

Authorial and institutional stratification in open access publishing: the case of global health research

PubMed Central

Haustein, Stefanie; Smith, Elise; Larivière, Vincent; Alperin, Juan Pablo

2018-01-01

Using a database of recent articles published in the field of Global Health research, we examine institutional sources of stratification in publishing access outcomes. Traditionally, the focus on inequality in scientific publishing has focused on prestige hierarchies in established print journals. This project examines stratification in contemporary publishing with a particular focus on subscription vs. various Open Access (OA) publishing options. Findings show that authors working at lower-ranked universities are more likely to publish in closed/paywalled outlets, and less likely to choose outlets that involve some sort of Article Processing Charge (APCs; gold or hybrid OA). We also analyze institutional differences and stratification in the APC costs paid in various journals. Authors affiliated with higher-ranked institutions, as well as hospitals and non-profit organizations pay relatively higher APCs for gold and hybrid OA publications. Results suggest that authors affiliated with high-ranked universities and well-funded institutions tend to have more resources to choose pay options with publishing. Our research suggests new professional hierarchies developing in contemporary publishing, where various OA publishing options are becoming increasingly prominent. Just as there is stratification in institutional representation between different types of publishing access, there is also inequality within access types. PMID:29479492

Superiority of delayed risk stratification in differentiated thyroid cancer after total thyroidectomy and radioactive iodine ablation.

PubMed

Hong, Chae Moon; Lee, Won Kee; Jeong, Shin Young; Lee, Sang-Woo; Ahn, Byeong-Cheol; Lee, Jaetae

2014-11-01

The aim of this study was to validate the effectiveness of delayed risk stratification (DRS) in predicting structural progression and compare the predictive value of American Thyroid Association (ATA) risk stratification with that of DRS in patients with differentiated thyroid cancer (DTC). A total of 398 patients with DTC who underwent surgery followed by radioactive iodine ablation were enrolled. Patients were categorized as having excellent response, acceptable response, biochemical incomplete response, or structural incomplete response at 8-15 months' evaluation after radioactive iodine ablation for DRS. Effectiveness of DRS was evaluated according to structural progression-free survival (PFS; median follow-up, 10.7 years). A total of 229 patients (57.5%) were classified as having excellent response, 78 (19.6%) as having acceptable response, 62 (15.6%) as having biochemical incomplete response, and 29 patients (7.3%) as having structural incomplete response. After DRS, 60.2% of intermediate-risk patients and 20.5% of high-risk patients were shifted to the excellent response category. Sixty-nine patients (17.3%) showed structural progression. DRS showed statistical difference in PFS (hazard ratio, 4.268; 95% confidence interval, 3.258-5.477; P<0.001). In multivariate analysis of ATA risk stratification and DRS, DRS was significantly associated with PFS (hazard ratio, 4.383; 95% confidence interval, 3.250-5.912; P<0.001), but ATA risk stratification was not. There was no significant difference in deviances between the use of DRS alone and the use of both DRS and ATA risk stratification (χ=0.103, d.f.=1, P=0.748). DRS is superior to ATA risk stratification in predicting structural disease progression for DTC patients.

Thermal stratification hinders gyrotactic micro-organism rising in free-surface turbulence

NASA Astrophysics Data System (ADS)

Lovecchio, Salvatore; Zonta, Francesco; Marchioli, Cristian; Soldati, Alfredo

2017-05-01

Thermal stratification in water bodies influences the exchange of heat, momentum, and chemical species across the air-water interface by modifying the sub-surface turbulence characteristics. Turbulence modifications may in turn prevent small motile algae (phytoplankton, in particular) from reaching the heated surface. We examine how different regimes of stable thermal stratification affect the motion of these microscopic organisms (modelled as gyrotactic self-propelling cells) in a free-surface turbulent channel flow. This archetypal setup mimics an environmentally plausible situation that can be found in lakes and oceans. Results from direct numerical simulations of turbulence coupled with Lagrangian tracking reveal that rising of bottom-heavy self-propelling cells depends strongly on the strength of stratification, especially near the thermocline where high temperature and velocity gradients occur: Here hydrodynamic shear may disrupt directional cell motility and hamper near-surface accumulation. For all gyrotactic re-orientation times considered in this study (spanning two orders of magnitude), we observe a reduction of the cell rising speed and temporary confinement under the thermocline: If re-orientation is fast, cells eventually trespass the thermocline within the simulated time span; if re-orientation is slow, confinement lasts much longer because cells align in the streamwise direction and their vertical swimming is practically annihilated.

Stratification of centrifuged amoeba nuclei investigated by electron microscopy

NASA Technical Reports Server (NTRS)

Breyer, E. P.; Daniels, E. W.

1968-01-01

Study establishes a relationship between radioresistance and the nucleolar stratification characteristics of various amoeba species. Two species of fresh water amoeba are studied with the electron microscope. The report discusses the nature of nucleolar layers and their possible relationship to the differences in radiosensitivity of the two amoeba species.

Pneumomédiastin compliquant une crise d’éclampsie: à propos d'un cas

PubMed Central

Doumiri, Mouhssine; Motiaa, Youssef; Oudghiri, Nezha; Saoud, Anas Tazi

2014-01-01

Le pneumomédiastin associé à l'emphysème sous cutané et le pneumothorax, sont des complications rares de la grossesse et surviennent au cours du travail obstétrical. Nous rapportons l'observation d'une parturiente de 25ans, sans antécédent pathologique particulier, admise pour une crise d’éclampsie à 36 semaines d'aménorrhées avec une mort fœtale et trouble de la conscience. L'examen clinique a montré un emphysème sous cutané étendu du visage jusqu’à l'abdomen sans notion de traumatisme et un score de Glasgow à 10. Après mise en condition, traitement de la crise d’éclampsie, stabilisation de la tension artérielle et retour à l’état de conscience, une TDM cervico-thoraco-abdominale a été demandée et a révélé la présence d'un pneumomédiastin important avec un discret pneumothorax droit postérieur et un pneumopéritoine important qui n'ont pas nécessité de drainage pleural. Deux jours après son admission, la patiente a expulsé un mort-né d'un poids de 1800 grammes avec forceps et sans efforts d'expulsions sous analgésie péridurale. Le contrôle radiologique à une semaine a noté une nette diminution de l'emphysème sous cutané et du pneumomédiastin. La patiente a quitté l'hôpital après dix jours. PMID:25838864

Fissuration d'un composite a matrice ceramique dans une application de piece statique de turbine a gaz

NASA Astrophysics Data System (ADS)

Lebel, Larry

Une procedure experimentale a ete developpee pour caracteriser les mecanismes de deterioration et la durabilite de materiaux composites a matrice ceramique (CMC) dans une application de piece statique de turbine a gaz. Tandis que la plupart des essais de caracterisation publies sur les materiaux CMC ont ete realises sous des conditions de chargement controle, la presente recherche tente de reproduire la relaxation des contraintes qui se produit normalement dans une piece statique a haute temperature. Dans l'experience proposee, un echantillon planaire de forme haltere est chauffe de facon cyclique sur une de ses faces et refroidi sur l'autre, tout en etant contraint dans ses deplacements. La contrainte de flexion resultante au centre de l'echantillon, mesuree par une cellule de charge, correspond a la contrainte de flexion qui a ete prealablement predite au centre des panneaux d'une chambre a combustion generique. Un materiau CMC multicouche compose d'une matrice d'alumine poreuse et de fibres NextelMD 720 a ete utilise pour developper l'experience. Des essais de calibration ont d'abord ete realises en utilisant un systeme de chauffage par lampe infrarouge, atteignant jusqu'a 1160 °C a la surface de l'echantillon. Un systeme laser au CO2 a par la suite ete utilise pour realiser des essais de deterioration a haute puissance, atteignant en fin d'essai des temperatures de surface excedant la limite de 1200 °C du materiau et des differences de temperature a travers l'epaisseur de plus de 1000 °C. Sous la puissance de chauffage imposee a amplitude constante, l'accumulation de dommage a fait en sorte d'augmenter la temperature en surface et les gradients de temperature a travers le materiau. Une reduction de la contrainte dans le temps a ete observee a cause du fluage, de la fissuration et de la delamination du materiau sous la condition de confinement du deplacement, menant a une stabilisation du niveau de dommage a une certaine profondeur dependant de la contrainte

Improving risk-stratification of Diabetes complications using temporal data mining.

PubMed

Sacchi, Lucia; Dagliati, Arianna; Segagni, Daniele; Leporati, Paola; Chiovato, Luca; Bellazzi, Riccardo

2015-01-01

To understand which factor trigger worsened disease control is a crucial step in Type 2 Diabetes (T2D) patient management. The MOSAIC project, funded by the European Commission under the FP7 program, has been designed to integrate heterogeneous data sources and provide decision support in chronic T2D management through patients' continuous stratification. In this work we show how temporal data mining can be fruitfully exploited to improve risk stratification. In particular, we exploit administrative data on drug purchases to divide patients in meaningful groups. The detection of drug consumption patterns allows stratifying the population on the basis of subjects' purchasing attitude. Merging these findings with clinical values indicates the relevance of the applied methods while showing significant differences in the identified groups. This extensive approach emphasized the exploitation of administrative data to identify patterns able to explain clinical conditions.

Epithelial stratification and placode invagination are separable functions in early morphogenesis of the molar tooth

PubMed Central

Li, Jingjing; Chatzeli, Lemonia; Panousopoulou, Eleni; Tucker, Abigail S.; Green, Jeremy B. A.

2016-01-01

Ectodermal organs, which include teeth, hair follicles, mammary ducts, and glands such as sweat, mucous and sebaceous glands, are initiated in development as placodes, which are epithelial thickenings that invaginate and bud into the underlying mesenchyme. These placodes are stratified into a basal and several suprabasal layers of cells. The mechanisms driving stratification and invagination are poorly understood. Using the mouse molar tooth as a model for ectodermal organ morphogenesis, we show here that vertical, stratifying cell divisions are enriched in the forming placode and that stratification is cell division dependent. Using inhibitor and gain-of-function experiments, we show that FGF signalling is necessary and sufficient for stratification but not invagination as such. We show that, instead, Shh signalling is necessary for, and promotes, invagination once suprabasal tissue is generated. Shh-dependent suprabasal cell shape suggests convergent migration and intercalation, potentially accounting for post-stratification placode invagination to bud stage. We present a model in which FGF generates suprabasal tissue by asymmetric cell division, while Shh triggers cell rearrangement in this tissue to drive invagination all the way to bud formation. PMID:26755699

Lupus érythémateux systémique induit par l'isoniazide: une complication rare à craindre

PubMed Central

Jguirim, Mahbouba; Jbeli, Amna; Brahim, Hajer Ben; Mhenni, Amira; Youssef, Monia; Touzi, Mongi; Zrour, Sawssen; Bejia, Ismail; Bergaoui, Naceur

2015-01-01

Le lupus induit est défini comme un syndrome lupique généralement cutanéo-articulaire secondaire à une exposition continue à un traitement et qui disparaît après arrêt de celle-ci. Nous rapportons deux cas de lupus induit par l'isoniazide. Il s'agissait de deux femmes âgées respectivement de 30 et 35 ans. Elles présentaient un lupus induit par l'isoniazide après un et deux mois de traitement d'une tuberculose ganglionnaire. La maladie s'est manifestée par des signes articulaires, une éruption cutanée, une leucopénie et une anémie. Les anticorps antinucléaires et les anticorps antihistone étaient présents dans le sérum des deux malades. L’évolution était favorable après arrêt de l'isoniazide et une corticothérapie per os. Les médicaments antituberculeux notamment l'isoniazide sont responsables d'effets indésirables fréquents. Le lupus induit doit être évoqué lorsqu'un patient présente un tableau clinico-biologique évocateur. PMID:26430478

Risk stratification in autoimmune cholestatic liver diseases: Opportunities for clinicians and trialists

PubMed Central

Trivedi, Palak J.; Corpechot, Christophe; Pares, Albert

2015-01-01

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are infrequent autoimmune cholestatic liver diseases, that disproportionate to their incidence and prevalence, remain very important causes of morbidity and mortality for patients with liver disease. Mechanistic insights spanning genetic risks and biological pathways to liver injury and fibrosis have led to a renewed interest in developing therapies beyond ursodeoxycholic acid that are aimed at both slowing disease course and improving quality of life. International cohort studies have facilitated a much greater understanding of disease heterogeneity, and in so doing highlight the opportunity to provide patients with a more individualized assessment of their risk of progressive liver disease, based on clinical, laboratory, or imaging findings. This has led to a new approach to patient care that focuses on risk stratification (both high and low risk); and furthermore allows such stratification tools to help identify patient subgroups at greatest potential benefit from inclusion in clinical trials. In this article, we review the applicability and validity of risk stratification in autoimmune cholestatic liver disease, highlighting strengths and weaknesses of current and emergent approaches. (Hepatology 2016;63:644–659) PMID:26290473

Noninvasive risk stratification for sudden death in asymptomatic patients with Wolff-Parkinson-White syndrome.

PubMed

Novella, John; DeBiasi, Ralph M; Coplan, Neil L; Suri, Ranji; Keller, Seth

2014-01-01

Sudden cardiac death (SCD) as the first clinical manifestation of Wolff-Parkinson-White (WPW) syndrome is a well-documented, although rare occurrence. The incidence of SCD in patients with WPW ranges from 0% to 0.39% annually. Controversy exists regarding risk stratification for patients with preexcitation on surface electrocardiogram (ECG), particularly in those who are asymptomatic. This article focuses on the role of risk stratification using exercise and pharmacologic testing in patients with WPW pattern on ECG.

Short-term vs. long-term heart rate variability in ischemic cardiomyopathy risk stratification.

PubMed

Voss, Andreas; Schroeder, Rico; Vallverdú, Montserrat; Schulz, Steffen; Cygankiewicz, Iwona; Vázquez, Rafael; Bayés de Luna, Antoni; Caminal, Pere

2013-01-01

In industrialized countries with aging populations, heart failure affects 0.3-2% of the general population. The investigation of 24 h-ECG recordings revealed the potential of nonlinear indices of heart rate variability (HRV) for enhanced risk stratification in patients with ischemic heart failure (IHF). However, long-term analyses are time-consuming, expensive, and delay the initial diagnosis. The objective of this study was to investigate whether 30 min short-term HRV analysis is sufficient for comparable risk stratification in IHF in comparison to 24 h-HRV analysis. From 256 IHF patients [221 at low risk (IHFLR) and 35 at high risk (IHFHR)] (a) 24 h beat-to-beat time series (b) the first 30 min segment (c) the 30 min most stationary day segment and (d) the 30 min most stationary night segment were investigated. We calculated linear (time and frequency domain) and nonlinear HRV analysis indices. Optimal parameter sets for risk stratification in IHF were determined for 24 h and for each 30 min segment by applying discriminant analysis on significant clinical and non-clinical indices. Long- and short-term HRV indices from frequency domain and particularly from nonlinear dynamics revealed high univariate significances (p < 0.01) discriminating between IHFLR and IHFHR. For multivariate risk stratification, optimal mixed parameter sets consisting of 5 indices (clinical and nonlinear) achieved 80.4% AUC (area under the curve of receiver operating characteristics) from 24 h HRV analysis, 84.3% AUC from first 30 min, 82.2 % AUC from daytime 30 min and 81.7% AUC from nighttime 30 min. The optimal parameter set obtained from the first 30 min showed nearly the same classification power when compared to the optimal 24 h-parameter set. As results from stationary daytime and nighttime, 30 min segments indicate that short-term analyses of 30 min may provide at least a comparable risk stratification power in IHF in comparison to a 24 h analysis period.

The Effect of an Isogrid on Cryogenic Propellant Behavior and Thermal Stratification

NASA Technical Reports Server (NTRS)

Oliveira, Justin; Kirk, Daniel R.; Chintalapati, Sunil; Schallhorn, Paul A.; Piquero, Jorge L.; Campbell, Mike; Chase, Sukhdeep

2007-01-01

All models for thermal stratification available in the presentation are derived using smooth, flat plate laminar and turbulent boundary layer models. This study examines the effect of isogrid (roughness elements) on the surface of internal tank walls to mimic the effects of weight-saving isogrid, which is located on the inside of many rocket propellant tanks. Computational Fluid Dynamics (CFD) is used to study the momentum and thermal boundary layer thickness for free convection flows over a wall with generic roughness elements. This presentation makes no mention of actual isogrid sizes or of any specific tank geometry. The magnitude of thermal stratification is compared for smooth and isogrid-lined walls.

Quantitative Stratification of Diffuse Parenchymal Lung Diseases

PubMed Central

Raghunath, Sushravya; Rajagopalan, Srinivasan; Karwoski, Ronald A.; Maldonado, Fabien; Peikert, Tobias; Moua, Teng; Ryu, Jay H.; Bartholmai, Brian J.; Robb, Richard A.

2014-01-01

Diffuse parenchymal lung diseases (DPLDs) are characterized by widespread pathological changes within the pulmonary tissue that impair the elasticity and gas exchange properties of the lungs. Clinical-radiological diagnosis of these diseases remains challenging and their clinical course is characterized by variable disease progression. These challenges have hindered the introduction of robust objective biomarkers for patient-specific prediction based on specific phenotypes in clinical practice for patients with DPLD. Therefore, strategies facilitating individualized clinical management, staging and identification of specific phenotypes linked to clinical disease outcomes or therapeutic responses are urgently needed. A classification schema consistently reflecting the radiological, clinical (lung function and clinical outcomes) and pathological features of a disease represents a critical need in modern pulmonary medicine. Herein, we report a quantitative stratification paradigm to identify subsets of DPLD patients with characteristic radiologic patterns in an unsupervised manner and demonstrate significant correlation of these self-organized disease groups with clinically accepted surrogate endpoints. The proposed consistent and reproducible technique could potentially transform diagnostic staging, clinical management and prognostication of DPLD patients as well as facilitate patient selection for clinical trials beyond the ability of current radiological tools. In addition, the sequential quantitative stratification of the type and extent of parenchymal process may allow standardized and objective monitoring of disease, early assessment of treatment response and mortality prediction for DPLD patients. PMID:24676019

Thermal Stratification Analysis for Sodium Fast Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schneider, James; Anderson, Mark; Baglietto, Emilio

The sodium fast reactor (SFR) is the most mature reactor concept of all the generation-IV nuclear systems and is a promising reactor design that is currently under development by several organizations. The majority of sodium fast reactor designs utilize a pool type arrangement which incorporates the primary coolant pumps and intermediate heat exchangers within the sodium pool. These components typically protrude into the pool thus reducing the risk and severity of a loss of coolant accidents. To further ensure safe operation under even the most severe transients a more comprehensive understanding of key thermal hydraulic phenomena in this pool ismore » desired. One of the key technology gaps identified for SFR safety is determining the extent and the effects of thermal stratification developing in the pool during postulated accident scenarios such as a protected or unprotected loss of flow incident. In an effort to address these issues, detailed flow models of transient stratification in the pool during an accident can be developed. However, to develop the calculation models, and ensure they can reproduce the underlying physics, highly spatially resolved data is needed. This data can be used in conjunction with advanced computational fluid dynamic calculations to aid in the development of simple reduced dimensional models for systems codes such as SAM and SAS4A/SASSYS-1.« less

Risk stratification, genomic data and the law.

PubMed

Hall, Alison; Finnegan, Thomas; Chowdhury, Susmita; Dent, Tom; Kroese, Mark; Burton, Hilary

2018-02-22

Risk prediction models have a key role in stratified disease prevention, and the incorporation of genomic data into these models promises more effective personalisation. Although the clinical utility of incorporating genomic data into risk prediction tools is increasingly compelling, at least for some applications and disease types, the legal and regulatory implications have not been examined and have been overshadowed by discussions about clinical and scientific utility and feasibility. We held a workshop to explore relevant legal and regulatory perspectives from four EU Member States: France, Germany, the Netherlands and the UK. While we found no absolute prohibition on the use of such data in those tools, there are considerable challenges. Currently, these are modest and result from genomic data being classified as sensitive data under existing Data Protection regulation. However, these challenges will increase in the future following the implementation of EU Regulations on data protection which take effect in 2018, and reforms to the governance of the manufacture, development and use of in vitro diagnostic devices to be implemented in 2022. Collectively these will increase the regulatory burden placed on these products as risk stratification tools will be brought within the scope of these new Regulations. The failure to respond to the challenges posed by the use of genomic data in disease risk stratification tools could therefore prove costly to those developing and using such tools.

Simulation d'ecoulements internes compressibles laminaires et turbulents par une methode d'elements finis

NASA Astrophysics Data System (ADS)

Rebaine, Ali

1997-08-01

Ce travail consiste en la simulation numerique des ecoulements internes compressibles bidimensionnels laminaires et turbulents. On s'interesse, particulierement, aux ecoulements dans les ejecteurs supersoniques. Les equations de Navier-Stokes sont formulees sous forme conservative et utilisent, comme variables independantes, les variables dites enthalpiques a savoir: la pression statique, la quantite de mouvement et l'enthalpie totale specifique. Une formulation variationnelle stable des equations de Navier-Stokes est utilisee. Elle est base sur la methode SUPG (Streamline Upwinding Petrov Galerkin) et utilise un operateur de capture des forts gradients. Un modele de turbulence, pour la simulation des ecoulements dans les ejecteurs, est mis au point. Il consiste a separer deux regions distinctes: une region proche de la paroi solide, ou le modele de Baldwin et Lomax est utilise et l'autre, loin de la paroi, ou une formulation nouvelle, basee sur le modele de Schlichting pour les jets, est proposee. Une technique de calcul de la viscosite turbulente, sur un maillage non structure, est implementee. La discretisation dans l'espace de la forme variationnelle est faite a l'aide de la methode des elements finis en utilisant une approximation mixte: quadratique pour les composantes de la quantite de mouvement et de la vitesse et lineaire pour le reste des variables. La discretisation temporelle est effectuee par une methode de differences finies en utilisant le schema d'Euler implicite. Le systeme matriciel, resultant de la discretisation spatio-temporelle, est resolu a l'aide de l'algorithme GMRES en utilisant un preconditionneur diagonal. Les validations numeriques ont ete menees sur plusieurs types de tuyeres et ejecteurs. La principale validation consiste en la simulation de l'ecoulement dans l'ejecteur teste au centre de recherche NASA Lewis. Les resultats obtenus sont tres comparables avec ceux des travaux anterieurs et sont nettement superieurs concernant les

Measuring Density Stratification and Understanding its Impact on Sediment Transport in Fine-grained Rivers, Based on Observations from the Lower Yellow River, China

NASA Astrophysics Data System (ADS)

Moodie, A. J.; Nittrouer, J. A.; Ma, H.; Lamb, M. P.; Carlson, B.; Kineke, G. C.; Parker, G.

2017-12-01

High concentrations of suspended sediment in channelized fluid flow produces density stratification that can alter the turbulent flow structure, thus limiting fluid momentum redistribution and affecting sediment transport capacity. A low channel-bed slope and large flow depth are hypothesized to be additional important factors contributing to density stratification. However, there are limited observations of density stratification in large rivers, especially those that carry significant fluxes of mud, and so the conditions leading to the development of density stratification are poorly constrained. The Yellow River, China, is a fine-grained and low-sloping river that maintains some of the highest suspended sediment concentrations in large rivers worldwide, making it an ideal natural laboratory for studying density stratification and its impact on sediment transport. Suspended sediment samples from the lower Yellow River, collected over a range of discharge conditions, produced sediment concentration profiles that are used in conjunction with velocity profiles to determine the threshold shear velocity for density stratification effects to develop. Comparing measured and predicted concentration and velocity profiles demonstrates that, there is no significant density stratification for base flow conditions; however, above a shear velocity value of 0.05 m/s, there is a progressive offset between the measured and predicted profiles, indicating that density stratification is increasingly important with higher shear stress values. The analyses further indicate that sediment entrainment from the bed and sediment diffusivity within the water column are significantly impacted by density stratification, suggesting that shear stress and sediment transport rates are inhibited by the development of density stratification. Near-bed concentration measurements are used to assess a stress-to-entrainment relationship, accounting for density stratification. These measurements are

Dysfonctionnements radio-induits du transport colique chez le rat

NASA Astrophysics Data System (ADS)

François, A.; Lebrun, F.; Ksas, B.; Aigueperse, J.; Gourmelon, P.; MacNaughton, W. K.; Griffiths, N. M.

1998-04-01

The symptom commonly associated with whole body irradiation is diarrhoea, a still quite obscure phenomenon, which leads to decreased chance of cure of irradiated people. The aim of this study was to provide evidence for dysfunction of intestinal water and electrolyte transport regulation by the enteric nervous system after exposure to ionising radiation. This study shows decreased capacity of enteric nervous system to influence colonic transport 3days after irradiation, correlated to a diminished response to a neurotransmitter: serotonin. Radio-induced diarrhea may result from epithelial structural injury but also from impaired regulatory processes of intestinal transport. L'un des symptômes majeurs d'une irradiation corporelle totale ou abdominale est l'apparition de diarrhées, dont les causes sont encore mal connues, et qui mettent en jeu le pronostique vital de l'individu irradié. Cette étude vise à mettre en évidence l'atteinte de la régulation du transport intestinal d'eau et d'électrolytes par les rayonnements ionisants. On observe une diminution de la capacité du système nerveux entérique à influencer le transport colique 3jours après irradiation, corrélée à une diminution de la réponse épithéliale à un neurotransmetteur : la sérotonine. Les diarrhées radio-induites résulteraient d'une atteinte structurelle de l'épithélium mais également des processus de régulation du transport intestinal.

Simultaneous observations of F2 layer stratification and spread F at postmidnight over a northern equatorial anomaly region

NASA Astrophysics Data System (ADS)

Jiang, Chunhua; Yang, Guobin; Deng, Chi; Zhou, Chen; Zhu, Peng; Yokoyama, Tatsuhiro; Song, Huan; Lan, Ting; Ni, Binbin; Zhao, Zhengyu; Zhang, Yuannong

2015-12-01

Simultaneous observations of F2 layer stratification and spread F at postmidnight (00:00 LT to 05:00 LT) were carried out on 22, 23, and 28 November 2013, using ionosondes distributed over a northern equatorial anomaly region at three specific locations, i.e., Puer (PUR, 22.7°N, 101.05°E, dip latitude 12.9°N), Chiang Mai (CMU, 18.8°N, 98.9°E, dip latitude 9.04°N), and Chumphon (CPN, 10.7°N, 99.4°E, dip latitude 0.93°N). The results show that both the PUR and CMU stations observed the F2 layer stratification at postmidnight in the Northern Hemisphere, frequently accompanied with gravity waves (the periods~30-100 min). It is reported that F2 layer stratification at postmidnight can be observed in the Northern Hemisphere for the first time. It is suggested that the thermospheric neutral wind triggered by gravity waves strongly contribute to the altitude dependence of the combined vertical plasma velocity, which consequently poses significant impacts on the occurrence of the low-latitude F2 layer stratification at postmidnight. In addition, the spread F other than F2 layer stratification was observed at the CPN station located at the geomagnetic equator, suggesting that smaller geomagnetic inclination tend to inhibit the postmidnight F2 layer stratification in the equatorial region. Furthermore, on 23 November 2013 a good correlation was identified between the F2 layer stratification at PUR and the spread F at both CMU and CPN, possibly due to that the large-scale gravity waves originating at middle latitudes contribute to the nighttime spread F observed in the low-latitude and equatorial regions.

Segmented Poincaré plot analysis for risk stratification in patients with dilated cardiomyopathy.

PubMed

Voss, A; Fischer, C; Schroeder, R; Figulla, H R; Goernig, M

2010-01-01

The prognostic value of heart rate variability in patients with dilated cardiomyopathy (DCM) is limited and does not contribute to risk stratification although the dynamics of ventricular repolarization differs considerably between DCM patients and healthy subjects. Neither linear nor nonlinear methods of heart rate variability analysis could discriminate between patients at high and low risk for sudden cardiac death. The aim of this study was to analyze the suitability of the new developed segmented Poincaré plot analysis (SPPA) to enhance risk stratification in DCM. In contrast to the usual applied Poincaré plot analysis the SPPA retains nonlinear features from investigated beat-to-beat interval time series. Main features of SPPA are the rotation of cloud of points and their succeeded variability depended segmentation. Significant row and column probabilities were calculated from the segments and led to discrimination (up to p<0.005) between low and high risk in DCM patients. For the first time an index from Poincaré plot analysis of heart rate variability was able to contribute to risk stratification in patients suffering from DCM.

Risk stratification for sudden death in arrhythmogenic right ventricular cardiomyopathy.

PubMed

Cadrin-Tourigny, Julia; Tadros, Rafik; Talajic, Mario; Rivard, Lena; Abadir, Sylvia; Khairy, Paul

2015-06-01

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC) is an uncommon but increasingly recognized inherited cardiomyopathy that is associated with malignant ventricular arrhythmias and sudden cardiac death, particularly in young individuals. The implantable cardioverter-defibrillator (ICD) is widely regarded as the only treatment modality with evidence to support improved survival in patients with ARVC and secondary prevention indications. In contrast, there is no universally accepted risk stratification scheme to guide ICD therapy for primary prevention against sudden cardiac death. Potential benefits must be weighed against the considerable risks of complications and inappropriate shocks in this young patient population. This article tackles the challenges of risk stratification for sudden cardiac death in ARVC and critically appraises available evidence for various proposed risk factors. The authors' over-arching objective is to provide the clinician with evidence-based guidance to inform decisions regarding the selection of appropriate candidates with ARVC for ICD therapy.

Increasing the Knowledge of Stratification in Shallow Coastal Environments

NASA Astrophysics Data System (ADS)

Ojo, T.; Bonner, J.; Hodges, B.; Maidment, D.; Montagna, P.; Minsker, B.

2006-12-01

A testbed has been established using Corpus Christi Bay as an environmental field facility to study the phenomenon of hypoxia that has been observed to develop at certain periods during the year. Stratification affects vertical turbulent mixing of heat, momentum and mass (or constituents) within the water column, in turn influencing the transport of material. The mixing threshold is dependent on the value of the Richardson Number, Ri with inhibition due to stratification occurring at low values (< 0.25) and complete vertical mixing occurring at high values (> 0.25) of Ri. Corpus Christi Bay with average depth of ~3 m is the largest among a system of five bays has been known to stratify due to inflows of hypersaline water (up to 50 psu) from adjoining bays, the Laguna Madre and Oso Bay. Laguna Madre is separated from the Gulf of Mexico by a barrier island and becomes hypersaline because of the imbalance between inflow of freshwater and bay evaporation. Hypersalinity also occurs in Oso Bay due to anthropogenic forcing from a power plant that draws 400 MGD of cooling water from the upper Laguna Madre, discharging waste water into Oso Bay. Several wastewater treatment plants also discharge directly into Oso Bay or its tributary streams. The objective of this study is to develop a methodology for prescribing a set of parameters required for modeling and characterization of hypoxia in this shallow wind-driven bay. The extent to which Ri is dependent on external forcing at the surface boundary was measured using our fully instrumented sensor platforms. Each sensor platform includes sensors for synchronic near-surface meteorological (wind velocity, barometric pressure, air temperature) and water column oceanographic (current, water temperature, conductivity, particle size distribution, particulate concentration, dissolved oxygen, nutrient) variables. These were measured using fixed and mobile vertical profiling sensor platforms. A 2D hydrodynamic model was initially

Etude aerodynamique d'un jet turbulent impactant une paroi concave

NASA Astrophysics Data System (ADS)

LeBlanc, Benoit

Etant donne la demande croissante de temperatures elevees dans des chambres de combustion de systemes de propulsions en aerospatiale (turbomoteurs, moteur a reaction, etc.), l'interet dans le refroidissement par jets impactant s'est vu croitre. Le refroidissement des aubes de turbine permet une augmentation de temperature de combustion, ce qui se traduit en une augmentation de l'efficacite de combustion et donc une meilleure economie de carburant. Le transfert de chaleur dans les au bages est influence par les aspects aerodynamiques du refroidissement a jet, particulierement dans le cas d'ecoulements turbulents. Un manque de comprehension de l'aerodynamique a l'interieur de ces espaces confinees peut mener a des changements de transfert thermique qui sont inattendus, ce qui augmente le risque de fluage. Il est donc d'interet pour l'industrie aerospatiale et l'academie de poursuivre la recherche dans l'aerodynamique des jets turbulents impactant les parois courbes. Les jets impactant les surfaces courbes ont deja fait l'objet de nombreuses etudes. Par contre des conditions oscillatoires observees en laboratoire se sont averees difficiles a reproduire en numerique, puisque les structures d'ecoulements impactants des parois concaves sont fortement dependantes de la turbulence et des effets instationnaires. Une etude experimentale fut realisee a l'institut PPRIME a l'Universite de Poitiers afin d'observer le phenomene d'oscillation dans le jet. Une serie d'essais ont verifie les conditions d'ecoulement laminaires et turbulentes, toutefois le cout des essais experimentaux a seulement permis d'avoir un apercu du phenomene global. Une deuxieme serie d'essais fut realisee numeriquement a l'Universite de Moncton avec l'outil OpenFOAM pour des conditions d'ecoulement laminaire et bidimensionnel. Cette etude a donc comme but de poursuivre l'enquete de l'aerodynamique oscillatoire des jets impactant des parois courbes, mais pour un regime d'ecoulement transitoire, turbulent

Water-Column Stratification Observed along an AUV-Tracked Isotherm

NASA Astrophysics Data System (ADS)

Zhang, Y.; Messié, M.; Ryan, J. P.; Kieft, B.; Stanway, M. J.; Hobson, B.; O'Reilly, T. C.; Raanan, B. Y.; Smith, J. M.; Chavez, F.

2016-02-01

Studies of marine physical, chemical and microbiological processes benefit from observing in a Lagrangian frame of reference, i.e. drifting with ambient water. Because these processes can be organized relative to specific density or temperature ranges, maintaining observing platforms within targeted environmental ranges is an important observing strategy. We have developed a novel method to enable a Tethys-class long-range autonomous underwater vehicle (AUV) (which has a propeller and a buoyancy engine) to track a target isotherm in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. In the June 2015 CANON (Controlled, Agile, and Novel Observing Network) Experiment in Monterey Bay, California, AUV Makai tracked a target isotherm for 13 hours to study the coastal upwelling system. The tracked isotherm started from 33 m depth, shoaled to 10 m, and then deepened to 29 m. The thickness of the tracked isotherm layer (within 0.3°C error from the target temperature) increased over this duration, reflecting weakened stratification around the isotherm. During Makai's isotherm tracking, another long-range AUV, Daphne, acoustically tracked Makai on a circular yo-yo trajectory, measuring water-column profiles in Makai's vicinity. A wave glider also acoustically tracked Makai, providing sea surface measurements on the track. The presented method is a new approach for studying water-column stratification, but requires careful analysis of the temporal and spatial variations mingled in the vehicles' measurements. We will present a synthesis of the water column's stratification in relation to the upwelling conditions, based on the in situ measurements by the mobile platforms, as well as remote sensing and mooring data.

Effect of stable stratification on dispersion within urban street canyons: A large-eddy simulation

NASA Astrophysics Data System (ADS)

Li, Xian-Xiang; Britter, Rex; Norford, Leslie K.

2016-11-01

This study employs a validated large-eddy simulation (LES) code with high tempo-spatial resolution to investigate the effect of a stably stratified roughness sublayer (RSL) on scalar transport within an urban street canyon. The major effect of stable stratification on the flow and turbulence inside the street canyon is that the flow slows down in both streamwise and vertical directions, a stagnant area near the street level emerges, and the vertical transport of momentum is weakened. Consequently, the transfer of heat between the street canyon and overlying atmosphere also gets weaker. The pollutant emitted from the street level 'pools' within the lower street canyon, and more pollutant accumulates within the street canyon with increasing stability. Under stable stratification, the dominant mechanism for pollutant transport within the street canyon has changed from ejections (flow carries high-concentration pollutant upward) to unorganized motions (flow carries high-concentration pollutant downward), which is responsible for the much lower dispersion efficiency under stable stratifications.

Effect of Stratification on Surface Properties of Corneal Epithelial Cells

PubMed Central

Yáñez-Soto, Bernardo; Leonard, Brian C.; Raghunathan, Vijay Krishna; Abbott, Nicholas L.; Murphy, Christopher J.

2015-01-01

Purpose The purpose of this study was to determine the influence of mucin expression in an immortalized human corneal epithelial cell line (hTCEpi) on the surface properties of cells, such as wettability, contact angle, and surface heterogeneity. Methods hTCEpi cells were cultured to confluence in serum-free medium. The medium was then replaced by stratification medium to induce mucin biosynthesis. The mucin expression profile was analyzed using quantitative PCR and Western blotting. Contact angles were measured using a two-immiscible liquid method, and contact angle hysteresis was evaluated by tilting the apparatus and recording advancing and receding contact angles. The spatial distribution of mucins was evaluated with fluorescently labeled lectin. Results hTCEpi cells expressed the three main ocular mucins (MUC1, MUC4, and MUC16) with a maximum between days 1 and 3 of the stratification process. Upon stratification, cells caused a very significant increase in contact angle hysteresis, suggesting the development of spatially discrete and heterogeneously distributed surface features, defined by topography and/or chemical functionality. Although atomic force microscopy measurements showed no formation of appreciable topographic features on the surface of the cells, we observed a significant increase in surface chemical heterogeneity. Conclusions The surface chemical heterogeneity of the corneal epithelium may influence the dynamic behavior of tear film by “pinning” the contact line between the cellular surface and aqueous tear film. Engineering the surface properties of corneal epithelium could potentially lead to novel treatments in dry eye disease. PMID:26747762

[Physiological and biochemical changes of seeds of Coptis chinensis Franch. in stratification and the effect of ABA treatment].

PubMed

Li, X; Chen, Y; Zhan, J

1997-05-01

The seeds of Coptis chinensis need stratification to break dormancy. In this paper the changes of enzyme activities DNA contents and protein contents in stratification under refrigeration and outdoor temperature conditions, as well as the influence of ABA treatment were studied.

Maintenance of Coastal Surface Blooms by Surface Temperature Stratification and Wind Drift

PubMed Central

Ruiz-de la Torre, Mary Carmen; Maske, Helmut; Ochoa, José; Almeda-Jauregui, César O.

2013-01-01

Algae blooms are an increasingly recurrent phenomenon of potentially socio-economic impact in coastal waters globally and in the coastal upwelling region off northern Baja California, Mexico. In coastal upwelling areas the diurnal wind pattern is directed towards the coast during the day. We regularly found positive Near Surface Temperature Stratification (NSTS), the resulting density stratification is expected to reduce the frictional coupling of the surface layer from deeper waters and allow for its more efficient wind transport. We propose that the net transport of the top layer of approximately 2.7 kilometers per day towards the coast helps maintain surface blooms of slow growing dinoflagellate such as Lingulodinium polyedrum. We measured: near surface stratification with a free-rising CTD profiler, trajectories of drifter buoys with attached thermographs, wind speed and direction, velocity profiles via an Acoustic Doppler Current Profiler, Chlorophyll and cell concentration from water samples and vertical migration using sediment traps. The ADCP and drifter data agree and show noticeable current shear within the first meters of the surface where temperature stratification and high cell densities of L. polyedrum were found during the day. Drifters with 1m depth drogue moved towards the shore, whereas drifters at 3 and 5 m depth showed trajectories parallel or away from shore. A small part of the surface population migrated down to the sea floor during night thus reducing horizontal dispersion. The persistent transport of the surface bloom population towards shore should help maintain the bloom in favorable environmental conditions with high nutrients, but also increasing the potential socioeconomic impact of the blooms. The coast wise transport is not limited to blooms but includes all dissolved and particulate constituents in surface waters. PMID:23593127

Quantitative analysis of biogeochemically controlled density stratification in an iron-meromictic lake

NASA Astrophysics Data System (ADS)

Nixdorf, E.; Boehrer, B.

2015-11-01

Lake stratification controls the cycling of dissolved matter within the water body. This is of particular interest in the case of meromictic lakes, where permanent density stratification of the deep water limits vertical transport, and a chemically different (reducing) milieu can be established. As a consequence, the geochemical setting and the mixing regime of a lake can stabilize each other mutually. We attempt a quantitative approach to the contribution of chemical reactions sustaining the density stratification. As an example, we chose the prominent case of iron meromixis in Waldsee near Doebern, a small lake that originated from near-surface underground mining of lignite. From a data set covering 4 years of monthly measured electrical conductivity profiles, we calculated summed conductivity as a quantitative variable reflecting the amount of electro-active substances in the entire lake. Seasonal variations followed the changing of the chemocline height. Coinciding changes of electrical conductivities in the monimolimnion indicated that a considerable share of substances, precipitated by the advancing oxygenated epilimnion, re-dissolved in the remaining anoxic deep waters and contributed considerably to the density stratification. In addition, we designed a lab experiment, in which we removed iron compounds and organic material from monimolimnetic waters by introducing air bubbles. Precipitates could be identified by visual inspection. Eventually, the remaining solutes in the aerated water layer looked similar to mixolimnetic Waldsee water. Due to its reduced concentration of solutes, this water became less dense and remained floating on nearly unchanged monimolimnetic water. In conclusion, iron meromixis as seen in Waldsee did not require two different sources of incoming waters, but the inflow of iron-rich deep groundwater and the aeration through the lake surface were fully sufficient for the formation of iron meromixis.

Maintenance of coastal surface blooms by surface temperature stratification and wind drift.

PubMed

Ruiz-de la Torre, Mary Carmen; Maske, Helmut; Ochoa, José; Almeda-Jauregui, César O

2013-01-01

Algae blooms are an increasingly recurrent phenomenon of potentially socio-economic impact in coastal waters globally and in the coastal upwelling region off northern Baja California, Mexico. In coastal upwelling areas the diurnal wind pattern is directed towards the coast during the day. We regularly found positive Near Surface Temperature Stratification (NSTS), the resulting density stratification is expected to reduce the frictional coupling of the surface layer from deeper waters and allow for its more efficient wind transport. We propose that the net transport of the top layer of approximately 2.7 kilometers per day towards the coast helps maintain surface blooms of slow growing dinoflagellate such as Lingulodinium polyedrum. We measured: near surface stratification with a free-rising CTD profiler, trajectories of drifter buoys with attached thermographs, wind speed and direction, velocity profiles via an Acoustic Doppler Current Profiler, Chlorophyll and cell concentration from water samples and vertical migration using sediment traps. The ADCP and drifter data agree and show noticeable current shear within the first meters of the surface where temperature stratification and high cell densities of L. polyedrum were found during the day. Drifters with 1m depth drogue moved towards the shore, whereas drifters at 3 and 5 m depth showed trajectories parallel or away from shore. A small part of the surface population migrated down to the sea floor during night thus reducing horizontal dispersion. The persistent transport of the surface bloom population towards shore should help maintain the bloom in favorable environmental conditions with high nutrients, but also increasing the potential socioeconomic impact of the blooms. The coast wise transport is not limited to blooms but includes all dissolved and particulate constituents in surface waters.

MULTIGENERATIONAL ASPECTS OF SOCIAL STRATIFICATION: ISSUES FOR FURTHER RESEARCH

PubMed Central

Mare, Robert D.

2014-01-01

The articles in this special issue show the vitality and progress of research on multigenerational aspects of social mobility, stratification, and inequality. The effects of the characteristics and behavior of grandparents and other kin on the statuses, resources, and positions of their descendants are best viewed in a demographic context. Intergenerational effects work through both the intergenerational associations of socioeconomic characteristics and also differential fertility and mortality. A combined socioeconomic and demographic framework informs a research agenda which addresses the following issues: how generational effects combine with variation in age, period, and cohort within each generation; distinguishing causal relationships across generations from statistical associations; how multigenerational effects vary across socioeconomic hierarchies, including the possibility of stronger effects at the extreme top and bottom; distinguishing between endowments and investments in intergenerational effects; multigenerational effects on associated demographic behaviors and outcomes (especially fertility and mortality); optimal tradeoffs among diverse types of data on multigenerational processes; and the variability across time and place in how kin, education, and other institutions affect stratification. PMID:24748709

MULTIGENERATIONAL ASPECTS OF SOCIAL STRATIFICATION: ISSUES FOR FURTHER RESEARCH.

PubMed

Mare, Robert D

2014-03-01

The articles in this special issue show the vitality and progress of research on multigenerational aspects of social mobility, stratification, and inequality. The effects of the characteristics and behavior of grandparents and other kin on the statuses, resources, and positions of their descendants are best viewed in a demographic context. Intergenerational effects work through both the intergenerational associations of socioeconomic characteristics and also differential fertility and mortality. A combined socioeconomic and demographic framework informs a research agenda which addresses the following issues: how generational effects combine with variation in age, period, and cohort within each generation; distinguishing causal relationships across generations from statistical associations; how multigenerational effects vary across socioeconomic hierarchies, including the possibility of stronger effects at the extreme top and bottom; distinguishing between endowments and investments in intergenerational effects; multigenerational effects on associated demographic behaviors and outcomes (especially fertility and mortality); optimal tradeoffs among diverse types of data on multigenerational processes; and the variability across time and place in how kin, education, and other institutions affect stratification.

Appendicite aigue non compliquée: y a-t- il une place pour le traitement conservateur

PubMed Central

El Khader, Ahmed; Lahkim, Mohamed; El Barni, Rachid; Achour, Abdessamad

2015-01-01

Le but de cette étude a été d’évaluer l'efficacité de l'antibiothérapie seule dans le traitement des appendicites aigues non compliquées. C'est une étude prospective, intéressant 68 patients ayant eu une appendicite aigue simple, de confirmation radiologique, traités par l'amoxicilline associée à l'acide clavulanique pendant 10 jours. L'appendicectomie a été réalisée en cas d'aggravation ou en cas de non amélioration au bout de 48heures de traitement. Le traitement conservateur a été efficace dans 82,35% avec une résolution complète des symptômes chez 56 patients. Les 12 cas restants (17,65%) ont subit une appendicectomie. l'appendicite a été gangréneuse dans 8 cas et phlegmoneuse dans 4 cas. Cinq des 56 patients, qui ont bien évolué sous traitement conservateur, ont été réadmis et opérés pour récidive, soit 8,9%. Deux cas ont eu une appendicite compliquée. L'appendicectomie reste le traitement de référence pour l'appendicite aigue, mais le traitement antibiotique peut être proposé en première intension à des patients présentant une appendicite aigue non compliquée. PMID:26327981

Nucléation, ascension et éclatement d'une bulle de champagne

NASA Astrophysics Data System (ADS)

Liger-Belair, G.

2006-03-01

People have long been fascinated by bubbles and foams dynamics, and since the pioneering work of Leonardo da Vinci in the early 16th century, this subject has generated a huge bibliography. However, only quite recently, much interest was devoted to bubbles in Champagne wines and carbonated beverages. Since the time of the benedictine monk dom Pierre Perignon (1638-1715), champagne is the wine of celebration. This fame is largely linked to the elegance of its effervescence and foaming properties. In this book, the latest results about the chemical physics behind the bubbling properties of Champagne and sparkling wines are collected and fully illustrated. The first chapter is devoted to the history of champagne and to a presentation of the tools of the physical chemistry of interfaces needed for a whole comprehension of the book. Then, the three main steps of a fleeting champagne bubble's life are presented in chronological order, that is, the bubble nucleation on the glass wall (Chap.2), the bubble ascent and growth through the liquid matrix (Chap.3), and the bursting of bubbles at the liquid surface (Chap.4), which constitutes the most intriguing, functional, and visually appealing step. L'objectif général de ce travail consacré à l'étude des processus physicochimiques liés à l'effervescence des vins de Champagne était de décortiquer les différentes étapes de la vie d'une bulle de champagne en conditions réelles de consommation, dans une flûte. Nous résumons ci-après les principaux résultats obtenus pour chacune des étapes de la vie de la bulle, depuis sa naissance sur les parois d'une flûte, jusqu'à son éclatement en surface. Nucléation À l'aide d'une caméra rapide munie d'un objectif de microscope, nous avons pu mettre à mal une idée largement répandue. Ce ne sont pas les anfractuosités de la surface du verre ou de la flûte qui sont responsable de la nucléation hétérogène des bulles, mais des particules adsorbées sur les parois du

Accident D’Electrisation et Hemorragie Cerebro-Meningee : A Propos D’une Observation

PubMed Central

Chaibdraa, A.; Medjellakh, M.S.; Saouli, A.; Bentakouk, M.C.

2008-01-01

Summary L'électrisation est un évènement accidentel qui diffère des autres pathologies occasionnant des brûlures graves, à cause de ses spécificités qui traduisent d'une part la destruction du revêtement cutané, mais également les effets directs ou indirects du courant électrique sur tout tissu de l'organisme rencontré lors de son passage, en particulier le tissu nerveux. Les manifestations neurologiques centrales sont nombreuses, en relation avec les effets de l'électricité sur le parenchyme cérébral ou une lésion associée à l'électrisation. Nous rapportons l'observation d'une hémorragie cérébro-meningée survenant au 3ème jour d'une électrisation grave. Cette complication est bien documentée dans la littérature traitant des accidents d'électrisation post-foudroiement. N'ayant pas rencontré de cas similaire publié lors des accidents dus au courant industriel, nous présentons cette observation, qui soulève le problème du mécanisme physiopathologique de survenue, difficile à trancher. PMID:21991125

Anévrisme de l'artère fémorale superficielle lié à une infection à salmonelle

PubMed Central

Mrad, Melek Ben; Hammamia, Mohammed Ben; Miri, Rim; Derbel, Bilel; Koubaa, Mohammed Ali; Ziadi, Jalel; Khayati, Adel

2015-01-01

Les anévrismes infectieux de l'axe fémoro-poplité sont rares et d’évolution silencieuse. Ils surviennent surtout chez les sujets immunodéprimés. Leur traitement fait appel souvent à l'exclusion chirurgicale associée ou non à un geste de revascularisation. Nous rapportons le cas d'un patient opéré pour un anévrisme de l'artère fémorale superficielle, lié à une infection à salmonelle, il a eu une résection de l'anévrysme et une revascularisation par greffe veineuse. Ce patient a été repris par la suite à deux reprise pour rupture du greffon veineux. Pour cette raison, nous étions contraints à une explantation du pontage et une ligature des 2 bouts de l'artère sans revascularisation. Malgré l'absence de revascularisation, l’évolution a été favorable sous couverture d'une une antibiothérapie adaptée. En cas d'anévrysme infectieux de l'axe fémoro-poplité par infection à salmonelle, le rétablissement de la continuité artérielle, même avec un greffon veineux, peut exposer au risque de rupture artérielle. PMID:26955409

Vertical stratification of the foliar fungal community in the world's tallest trees.

PubMed

Harrison, Joshua G; Forister, Matthew L; Parchman, Thomas L; Koch, George W

2016-12-01

The aboveground tissues of plants host numerous, ecologically important fungi, yet patterns in the spatial distribution of these fungi remain little known. Forest canopies in particular are vast reservoirs of fungal diversity, but intracrown variation in fungal communities has rarely been explored. Knowledge of how fungi are distributed throughout tree crowns will contribute to our understanding of interactions between fungi and their host trees and is a first step toward investigating drivers of community assembly for plant-associated fungi. Here we describe spatial patterns in fungal diversity within crowns of the world's tallest trees, coast redwoods (Sequoia sempervirens). We took a culture-independent approach, using the Illumina MiSeq platform, to characterize the fungal assemblage at multiple heights within the crown across the geographical range of the coast redwood. Within each tree surveyed, we uncovered evidence for vertical stratification in the fungal community; different portions of the tree crown harbored different assemblages of fungi. We also report between-tree variation in the fungal community within redwoods. Our results suggest the potential for vertical stratification of fungal communities in the crowns of other tall tree species and should prompt future study of the factors giving rise to this stratification. © 2016 Botanical Society of America.

Modeling the periodic stratification and gravitational circulation in San Francisco Bay, California

USGS Publications Warehouse

Cheng, Ralph T.; Casulli, Vincenzo

1996-01-01

A high resolution, three-dimensional (3-D) hydrodynamic numerical model is applied to San Francisco Bay, California to simulate the periodic tidal stratification caused by tidal straining and stirring and their long-term effects on gravitational circulation. The numerical model is formulated using fixed levels in the vertical and uniform computational mesh on horizontal planes. The governing conservation equations, the 3-D shallow water equations, are solved by a semi-implicit finite-difference scheme. Numerical simulations for estuarine flows in San Francisco Bay have been performed to reproduce the hydrodynamic properties of tides, tidal and residual currents, and salt transport. All simulations were carried out to cover at least 30 days, so that the spring-neap variance in the model results could be analyzed. High grid resolution used in the model permits the use of a simple turbulence closure scheme which has been shown to be sufficient to reproduce the tidal cyclic stratification and well-mixed conditions in the water column. Low-pass filtered 3-D time-series reveals the classic estuarine gravitational circulation with a surface layer flowing down-estuary and an up-estuary flow near the bottom. The intensity of the gravitational circulation depends upon the amount of freshwater inflow, the degree of stratification, and spring-neap tidal variations.

Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

NASA Astrophysics Data System (ADS)

Bandriyana, B.; Utaja

2010-06-01

Thermal stratification introduces thermal shock effect which results in local stress and fatique problems that must be considered in the design of nuclear power plant components. Local stress and fatique calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343° C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

Forme pseudo tumorale d'une pneumopathie chronique à éosinophiles d’évolution fatale

PubMed Central

Hammoune, Nabil; El Guendouz, Faycal; Elhaddad, Siham; Janah, Hicham; Hommadi, Abdelaziz

2015-01-01

La pneumopathie chronique idiopathique à éosinophile est une pathologie rare, de cause inconnue, caractérisée par des opacités pulmonaires périphériques, une éosinophilie périphérique >1000/mm3 et /ou une éosinophilie alvéolaire >25%. Le diagnostic est difficile à cause de la non spécificité des signes cliniques et radiologiques. Le traitement se base essentiellement sur la corticothérapie. L’évolution est généralement favorable. Nous rapportons un cas de cette entité rare dans sa forme pseudotumorale sans hyperéosinophilie, de diagnostic tardif suite à l’étude histologique de la lobectomie chirurgicale et d’évolution fatale. PMID:26113897

Localisation humérale d'une tumeur à cellules géantes récidivantes (à propos d'un cas)

PubMed Central

Nader, Youssef; Serghini, Issam; Koulali, Idrissi Khalid; Salahi, Hicham; Galwia, Farid

2015-01-01

Les auteurs rapportent un cas de localisation rare d'une tumeur à cellules géantes au niveau de la palette humérale du coude droit chez un militaire de 36 ans de sexe masculin, la radio standard montrait une image kystique ne soufflant pas la corticale. L'examen anatomo-pathologique a permis d’ établir le diagnostic et le traitement a fait appel: au début a une Exérèse chirurgicale totale et une greffe osseuse par un greffon iliaque de la totalité de la palette huméral qui s'est compliquée à 6 mois de recule d une récidive locale. PMID:25995809

Impact of Arctic shelf summer stratification on Holocene climate variability

NASA Astrophysics Data System (ADS)

Thibodeau, Benoit; Bauch, Henning A.; Knies, Jochen

2018-07-01

Understanding the dynamic of freshwater and sea-ice export from the Arctic is crucial to better comprehend the potential near-future climate change consequences. Here, we report nitrogen isotope data of a core from the Laptev Sea to shed light on the impact of the Holocene Siberian transgression on the summer stratification of the Laptev Sea. Our data suggest that the oceanographic setting was less favourable to sea-ice formation in the Laptev Sea during the early to mid-Holocene. It is only after the sea level reached a standstill at around 4 ka that the water column structure in the Laptev Sea became more stable. Modern-day conditions, often described as "sea-ice factory", were reached about 2 ka ago, after the development of a strong summer stratification. These results are consistent with sea-ice reconstruction along the Transpolar Drift, highlighting the potential contribution of the Laptev Sea to the export of freshwater from the Arctic Ocean.

Space Shuttle Upgrade Liquid Oxygen Tank Thermal Stratification

NASA Technical Reports Server (NTRS)

Tunc, Gokturk; Wagner, Howard; Bayazitoglu, Yildiz

2001-01-01

In 1997, NASA initiated a study of a liquid oxygen and ethanol orbital maneuvering and reaction control system for space shuttle upgrades as well as other reusable launch vehicle applications. The pressure-fed system uses sub-cooled liquid oxygen at 2413.2 KPa (350 psia) stored passively using insulation. Thermal stratification builds up while the space shuttle is docked at the international space station. The venting from the space shuttle's liquid oxygen tank is not desired during this 96-hr time period. Once the shuttle undocks from the space station there could be a pressure collapse in the liquid oxygen tank caused by fluid mixing due to the thruster fU"ings . The thermal stratification and resulting pressure rise in the tank were examined by a computational fluid dynamic model. Since the heat transfer from the pressurant gas to the liquid will result in a decrease in tank pressure the final pressure after the 96 hours will be significantly less when the tank is pressurized with ambient temperature helium. Therefore, using helium at ambient temperature to pressurize the tank is preferred to pressurizing the tank with helium at the liquid oxygen temperature. The higher helium temperature will also result in less mass of helium to pressurize the tank.

Caracterisation de la cohesion de l'interface AMF/polymere dans une structure deformable adaptative

NASA Astrophysics Data System (ADS)

Fischer-Rousseau, Charles

Les structures déformables adaptatives (SDA) sont appelées à jouer un rôle important en aéronautique entre autres. Les alliages à mémoire de forme (AMF) sont un des candidats les plus prometteurs. Beaucoup de travail reste toutefois à faire avant que ces structures rencontrent les exigences élevées reliées à leur intégration dans un contexte aéronautique. Des travaux de recherche ont montré que la résistance à la décohésion de l’interface AMF/polymère peut être un élément limitant dans la performance des SDA. Dans ce travail, l’effet sur la résistance à la décohésion de l’interface AMF/polymère de divers traitements de surface, géométries de fil et types de polymère est évalué. La géométrie du fil est modifiée par une combinaison spécifique de laminage à froid et de recuit postdéformation qui maintient les propriétés de mémoire de forme tout en permettant de réduire l’aire de la section transversale du fil. Le traitement thermomécanique le plus prometteur est proposé. Une nouvelle méthode d’évaluation de la résistance à la décohésion est développée. Plutôt que de tester les fils en arrachement et de mesurer la force maximale, les tests en contraction sont basés sur la capacité des fils d’AMF à se contracter s’ils ont été encastrés dans un état tiré et qu’ils sont chauffés par effet Joule. L’hypothèse qu’on pose est que ces tests sont une meilleure approximation des conditions rencontrées dans une SDA, où les fils se contractent plutôt qu’ils sont arrachés par une force externe à la structure. Bien qu’une décohésion partielle ait été observée pour tous les échantillons, l’aire de la surface où il y a décohésion tait plus grande pour les échantillons avec une pré-déformation plus grande. Le front de décohésion a semblé cesser de progresser après les cycles de chauffage initiaux lorsque la vitesse de chauffage était faible. Un modèle numérique simulant la

Percentage of Positive Biopsy Cores: A Better Risk Stratification Model for Prostate Cancer?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang Jiayi; Vicini, Frank A.; Williams, Scott G.

2012-07-15

Purpose: To assess the prognostic value of the percentage of positive biopsy cores (PPC) and perineural invasion in predicting the clinical outcomes after radiotherapy (RT) for prostate cancer and to explore the possibilities to improve on existing risk-stratification models. Methods and Materials: Between 1993 and 2004, 1,056 patients with clinical Stage T1c-T3N0M0 prostate cancer, who had four or more biopsy cores sampled and complete biopsy core data available, were treated with external beam RT, with or without a high-dose-rate brachytherapy boost at William Beaumont Hospital. The median follow-up was 7.6 years. Multivariate Cox regression analysis was performed with PPC, Gleasonmore » score, pretreatment prostate-specific antigen, T stage, PNI, radiation dose, androgen deprivation, age, prostate-specific antigen frequency, and follow-up duration. A new risk stratification (PPC classification) was empirically devised to incorporate PPC and replace the T stage. Results: On multivariate Cox regression analysis, the PPC was an independent predictor of distant metastasis, cause-specific survival, and overall survival (all p < .05). A PPC >50% was associated with significantly greater distant metastasis (hazard ratio, 4.01; 95% confidence interval, 1.86-8.61), and its independent predictive value remained significant with or without androgen deprivation therapy (all p < .05). In contrast, PNI and T stage were only predictive for locoregional recurrence. Combining the PPC ({<=}50% vs. >50%) with National Comprehensive Cancer Network risk stratification demonstrated added prognostic value of distant metastasis for the intermediate-risk (hazard ratio, 5.44; 95% confidence interval, 1.78-16.6) and high-risk (hazard ratio, 4.39; 95% confidence interval, 1.70-11.3) groups, regardless of the use of androgen deprivation and high-dose RT (all p < .05). The proposed PPC classification appears to provide improved stratification of the clinical outcomes relative to the

SIOP‐PODC adapted risk stratification and treatment guidelines: Recommendations for neuroblastoma in low‐ and middle‐income settings

PubMed Central

Howard, Scott C.; Chantada, Guillermo; Israels, Trijn; Khattab, Mohammed; Alcasabas, Patricia; Lam, Catherine G.; Faulkner, Lawrence; Park, Julie R.; London, Wendy B.; Matthay, Katherine K.

2015-01-01

Neuroblastoma is the most common extracranial solid tumor in childhood in high‐income countries (HIC), where consistent treatment approaches based on clinical and tumor biological risk stratification have steadily improved outcomes. However, in low‐ and middle‐ income countries (LMIC), suboptimal diagnosis, risk stratification, and treatment may occur due to limited resources and unavailable infrastructure. The clinical practice guidelines outlined in this manuscript are based on current published evidence and expert opinions. Standard risk stratification and treatment explicitly adapted to graduated resource settings can improve outcomes for children with neuroblastoma by reducing preventable toxic death and relapse. Pediatr Blood Cancer 2015;62:1305–1316. © 2015 The Authors. Pediatric Blood & Cancer, published by Wiley Periodicals, Inc. PMID:25810263

Déclenchement du travail à terme par le misoprostol: expérience d'une maternité tunisienne

PubMed Central

Ouerdiane, Nadia; Tlili, Nihel; Othmani, Kaouther; Daaloul, Walid; Masmoudi, Abdelwaheb; Hamouda, Sonia Ben; Bouguerra, Badreddine

2016-01-01

Evaluer l'efficacité et l'innocuité de l'utilisation du misoprostol par voie vaginale pour le déclenchement du travail à terme. Etude prospective réalisée au service de gynécologie obstétrique B de l'hôpital Charles Nicolle de Tunis sur une durée de 4 mois. La population sélectionnée concernait les patientes à terme devant bénéficier d'une maturation cervicale. Le misoprostol à la dose de 50 µg par voie vaginale toutes les 12 h était utilisé. Les paramètres étudiés étaient les anomalies contractiles, les anomalies du RCF, le mode d'accouchement, le délai d'accouchement et l’état néonatal. 44 patientes ont bénéficié d'une maturation cervicale par misoprostol. Le terme moyen était de 40 SA. Le taux de nullipare était de 23/44 (52%). Le taux d'accouchement par voie basse était de 31/44 (70.4%). 84% des patientes ont reçu une seule dose de misoprostol. Les anomalies du RCF ont été notées dans 14/44 (32%). Le taux de liquides méconiaux était de 12/44 (27%). Un score d'Apgar à 5 mn inférieur à 7 était noté chez 7/44 (16%). Un cas de rupture utérine était survenue chez une primipare et ce après une seule prise de misoprostol. Nos résultats sont décevants en raison de la survenue d'une rupture utérine et d'une morbidité néonatale importante. D'autres études prospectives multicentriques restent utiles pour mieux s'assurer de l'efficacité mais surtout de l'innocuité du misoprostol à dose faible pour le déclenchement du travail à terme. PMID:27583092

Stratification at the Earth's largest hyperacidic lake and its consequences

NASA Astrophysics Data System (ADS)

Caudron, Corentin; Campion, Robin; Rouwet, Dmitri; Lecocq, Thomas; Capaccioni, Bruno; Syahbana, Devy; Suparjan; Purwanto, Bambang Heri; Bernard, Alain

2017-02-01

Volcanic lakes provide windows into the interior of volcanoes as they integrate the heat flux discharged by a magma body and condense volcanic gases. Volcanic lake temperatures and geochemical compositions therefore typically serve as warnings for resumed unrest or prior to eruptions. If acidic and hot, these lakes are usually considered to be too convective to allow any stratification within their waters. Kawah Ijen volcano, featuring the largest hyperacidic lake on Earth (volume of 27 million m3), is less homogeneous than previously thought. Hourly temperature measurements reveal the development of a stagnant layer of cold waters (<30 °C), overlying warmer and denser water (generally above 30 °C and density ∼1.083 kg/m3). Examination of 20 yrs of historical records and temporary measurements show a systematic thermal stratification during rainy seasons. The yearly rupture of stratification at the end of the rainy season causes a sudden release of dissolved gases below the cold water layer which appears to generate a lake overturn, i.e. limnic eruption, and a resonance of the lake, i.e. a seiche, highlighting a new hazard for these extreme reservoirs. A minor non-volcanic event, such as a heavy rainfall or an earthquake, may act as a trigger. The density driven overturn requires specific salinity-temperature conditions for the colder and less saline top water layer to sink into the hot saline water. Spectacular degassing occurs when the dissolved gases, progressively stored during the rainy season due to a weakened diffusion of carbon dioxide in the top layer, are suddenly released. These findings challenge the homogenization assumption at acidic lakes and stress the need to develop appropriate monitoring setups.

Recycling irrigation reservoir stratification and implications for crop health and production.

USDA-ARS?s Scientific Manuscript database

Stratification is often assumed to only take place in deep water bodies. Recycling irrigation reservoirs often are shallow; however, they receive agricultural runoff containing elevated concentrations of nutrients and sediments. This study investigated the temperature, dissolved oxygen and pH charac...

USA Stratified Monopoly: A Simulation Game about Social Class Stratification

ERIC Educational Resources Information Center

Fisher, Edith M.

2008-01-01

Effectively teaching college students about social class stratification is a difficult challenge. Explanations for this difficulty tend to focus on the students who often react with resistance, paralysis, or rage. Sociologists have been using games and simulations as alternative methods for several decades to teach about these sensitive subjects.…

Quantitative description of the effect of stratification on dormancy release of grape seeds in response to various temperatures and water contents

PubMed Central

Wang, W. Q.; Song, S. Q.; Li, S. H.; Gan, Y. Y.; Wu, J. H.; Cheng, H. Y.

2009-01-01

The effect of stratification on dormancy release of grape seeds crossing from the sub- to the supraoptimal range of temperatures and water contents was analysed by modified threshold models. The stratification impacted on dormancy release in three different ways: (i) dormancy was consistently released with prolonged stratification time when stratified at temperatures of <15 °C; (ii) at 15 °C and 20 °C, the stratification effect initially increased, and then decreased with extended time; and (iii) stratification at 25 °C only reduced germinable seeds. These behaviours indicated that stratification could not only release primary dormancy but also induce secondary dormancy in grape seed. The rate of dormancy release changed linearly in two phases, while induction increased exponentially with increasing temperature. The thermal time approaches effectively quantified dormancy release only at suboptimal temperature, but a quantitative method to integrate the occurrence of dormancy release and induction at the same time could describe it well at either sub- or supraoptimal temperatures. The regression with the percentage of germinable seeds versus stratification temperature or water content within both the sub- and supraoptimal range revealed how the optimal temperature (Tso) and water content (Wso) for stratification changed. The Tso moved from 10.6 °C to 5.3 °C with prolonged time, while Wso declined from >0.40 g H2O g DW−1 at 5 °C to ∼0.23 g H2O g DW−1 at 30 °C. Dormancy release in grape seeds can occur across a very wide range of conditions, which has important implications for their ability to adapt to a changeable environment in the wild. PMID:19491305

Effects of moist cold stratification on germination, plant growth regulators, metabolites and embryo ultrastructure in seeds of Acer morrisonense (Sapindaceae).

PubMed

Chen, Shun-Ying; Chou, Shih-Han; Tsai, Ching-Chu; Hsu, Wen-Yu; Baskin, Carol C; Baskin, Jerry M; Chien, Ching-Te; Kuo-Huang, Ling-Long

2015-09-01

Breaking of seed dormancy by moist cold stratification involves complex interactions in cells. To assess the effect of moist cold stratification on dormancy break in seeds of Acer morrisonense, we monitored percentages and rates of germination and changes in plant growth regulators, sugars, amino acids and embryo ultrastructure after various periods of cold stratification. Fresh seeds incubated at 25/15 °C for 24 weeks germinated to 61%, while those cold stratified at 5 °C for 12 weeks germinated to 87% in 1 week. Neither exogenous GA3 nor GA4 pretreatment significantly increased final seed germination percentage. Total ABA content of seeds cold stratified for 12 weeks was reduced about 3.3-fold, to a concentration similar to that in germinated seeds (radicle emergence). Endogenous GA3 and GA7 were detected in 8-week and 12-week cold stratified seeds but not in fresh seeds. Numerous protein and lipid bodies were present in the plumule, first true leaves and cotyledons of fresh seeds. Protein and lipid bodies decreased greatly during cold stratification, and concentrations of total soluble sugars and amino acids increased. The major non-polar sugars in fresh seeds were sucrose and fructose, but sucrose increased and fructose decreased significantly during cold stratification. The major free amino acids were proline and tryptophan in fresh seeds, and proline increased and tryptophan decreased during cold stratification. Thus, as dormancy break occurs during cold stratification seeds of A. morrisonense undergo changes in plant growth regulators, proteins, lipids, sugars, amino acids and cell ultrastructure. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Une forme exceptionnelle de la luxation perilunaire du carpe

PubMed Central

Elouakili, Issam; Ouchrif, Younes; Najib, Abdeljaouad; Ouakrim, Redouane; Lamrani, Omar; Kharmaz, Mohammed; Ismael, Farid; Lahlou, Abdo; Elouadghiri, Mohammed; El Bardouni, Ahmed; Mahfoud, Mustapha; Berrada, Mohammed Saleh; El Yaccoubi, Mouradh

2014-01-01

Les luxations périlunaires (LPL) du carpe sont des lésions extrêmement rares, qui peuvent passer inaperçue en raison d'un tableau clinique souvent trompeur, des radiographies en profil non strict ou d'interprétation difficile. Nous rapportons l'observation d'une luxation périlunaire stade III selon la classification de Witvoët et Allieu chez un patient de 32 ans, il s'agit d'une forme encore plus rare voire exceptionnelle et qui peut induire de sérieux problèmes en raison de la sévérité des dommages ligamentaires et du risque de nécrose du semilunaire plus important dans ce type de lésions. Le traitement est toujours chirurgical et doit être réalisé dans les plus brefs délais afin d’éviter les complications. PMID:25404968

Malaria ecotypes and stratification.

PubMed

Schapira, Allan; Boutsika, Konstantina

2012-01-01

To deal with the variability of malaria, control programmes need to stratify their malaria problem into a number of smaller units. Such stratification may be based on the epidemiology of malaria or on its determinants such as ecology. An ecotype classification was developed by the World Health Organization (WHO) around 1990, and it is time to assess its usefulness for current malaria control as well as for malaria modelling on the basis of published research. Journal and grey literature was searched for articles on malaria or Anopheles combined with ecology or stratification. It was found that all malaria in the world today could be assigned to one or more of the following ecotypes: savanna, plains and valleys; forest and forest fringe; foothill; mountain fringe and northern and southern fringes; desert fringe; coastal and urban. However, some areas are in transitional or mixed zones; furthermore, the implications of any ecotype depend on the biogeographical region, sometimes subregion, and finally, the knowledge on physiography needs to be supplemented by local information on natural, anthropic and health system processes including malaria control. Ecotyping can therefore not be seen as a shortcut to determine control interventions, but rather as a framework to supplement available epidemiological and entomological data so as to assess malaria situations at the local level, think through the particular risks and opportunities and reinforce intersectoral action. With these caveats, it does however emerge that several ecotypic distinctions are well defined and have relatively constant implications for control within certain biogeographic regions. Forest environments in the Indo-malay and the Neotropics are, with a few exceptions, associated with much higher malaria risk than in adjacent areas; the vectors are difficult to control, and the anthropic factors also often converge to impose constraints. Urban malaria in Africa is associated with lower risk than savanna

Myélome multiple survenant au cours d'une Fièvre Méditerranéenne Familiale

PubMed Central

Salem, Bouomrani; Afef, Farah; Nadia, Bouassida; Nabil, Ayadi; Zouhir, Bahloul; Maher, Béji

2013-01-01

L'objectif de ce travail est de rapporter une observation particulière de myélome multiple survenant au cours d'une maladie périodique. Il s'agit d'un patient tunisien de 53 ans suivi depuis le jeune âge pour maladie périodique dont le diagnostic était confirmé par l’étude génétique montrant l'homozygotie pour la mutation M694V du gène MEFV, fut admis pour exploration d'une douleur avec tuméfaction fessière droite récente. Les explorations biologiques et radiologiques ont permis de retenir le diagnostic d'un myélome multiple de type IgA à chaînes légères kappa stade III B, associé à une volumineuse localisation plasmocytaire très agressive de l'aile iliaque droite envahissant les structures musculaires avoisinantes. Notre observation, qui à notre connaissance est la deuxième signalant une telle association, se distingue par sa survenue brutale, sa progression rapide et le caractère très agressif de l'hémopathie. PMID:24255729

Stratification of welding fumes and grinding particles in a large factory hall equipped with displacement ventilation.

PubMed

Niemelä, R; Koskela, H; Engström, K

2001-08-01

The purpose of the study was to investigate the performance of displacement ventilation in a large factory hall where large components of stainless steel for paper, pulp and chemical industries were manufactured. The performance of displacement ventilation was evaluated in terms of concentration distributions of welding fumes and grinding particles, flow field of the supply air and temperature distributions. Large differences in vertical stratification patterns between hexavalent chromium (Cr(VI)) and other particulate contaminants were observed. The concentration of Cr(VI) was notably lower in the zone of occupancy than in the upper part of the factory hall, whereas the concentrations of total airborne particles and trivalent chromium (Cr(III)) were higher in the occupied zone than in the upper zone. The stratification of Cr(VI) had the same tendency as the air temperature stratification caused by the displacement flow field.

Tuméfaction du muscle pectoral révélant une tuberculose musculaire isolée

PubMed Central

Hayoun, Sohaib; Ouazzani, Hanane El; Habibi, Bouchra; Belhabib, Salwa; Souhi, Hicham; Rhorfi, Ismail Abderahmane; Abid, Ahmed

2017-01-01

La tuberculose des parties molles représente l’une des formes rares de la tuberculose extra pulmonaire, la localisation musculaire isolée est par-ailleurs exceptionnelle. Nous rapportant une observation médicale originale, une tuberculose musculaire isolée intéressant le muscle grand pectoral chez un jeune patient immunocompétent. Le diagnostic a reposé essentiellement sur l’histologie. L’évolution été favorable sous traitement anti bacillaire seul. Ce cas rare est présenté avec revue de littérature. PMID:28761620

Accurate Diabetes Risk Stratification Using Machine Learning: Role of Missing Value and Outliers.

PubMed

Maniruzzaman, Md; Rahman, Md Jahanur; Al-MehediHasan, Md; Suri, Harman S; Abedin, Md Menhazul; El-Baz, Ayman; Suri, Jasjit S

2018-04-10

Diabetes mellitus is a group of metabolic diseases in which blood sugar levels are too high. About 8.8% of the world was diabetic in 2017. It is projected that this will reach nearly 10% by 2045. The major challenge is that when machine learning-based classifiers are applied to such data sets for risk stratification, leads to lower performance. Thus, our objective is to develop an optimized and robust machine learning (ML) system under the assumption that missing values or outliers if replaced by a median configuration will yield higher risk stratification accuracy. This ML-based risk stratification is designed, optimized and evaluated, where: (i) the features are extracted and optimized from the six feature selection techniques (random forest, logistic regression, mutual information, principal component analysis, analysis of variance, and Fisher discriminant ratio) and combined with ten different types of classifiers (linear discriminant analysis, quadratic discriminant analysis, naïve Bayes, Gaussian process classification, support vector machine, artificial neural network, Adaboost, logistic regression, decision tree, and random forest) under the hypothesis that both missing values and outliers when replaced by computed medians will improve the risk stratification accuracy. Pima Indian diabetic dataset (768 patients: 268 diabetic and 500 controls) was used. Our results demonstrate that on replacing the missing values and outliers by group median and median values, respectively and further using the combination of random forest feature selection and random forest classification technique yields an accuracy, sensitivity, specificity, positive predictive value, negative predictive value and area under the curve as: 92.26%, 95.96%, 79.72%, 91.14%, 91.20%, and 0.93, respectively. This is an improvement of 10% over previously developed techniques published in literature. The system was validated for its stability and reliability. RF-based model showed the best

Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma.

PubMed

De Paz, Dante; Kao, Huang-Kai; Huang, Yenlin; Chang, Kai-Ping

2017-08-10

Prognosis of advanced oral squamous cell carcinoma remains a challenge for clinicians despite progress in its diagnosis and treatment over the past decades. In this review, we assessed clinicopathological factors and potential biomarkers along with their prognostic relevance in an attempt to develop optimal treatment strategies for these patients. In addition to several pathologic factors that have been proposed to improve prognostic stratification and treatment planning in the eighth edition of the American Joint Committee staging manual on cancer, we reviewed some other imaging and clinicopathological parameters demonstrated to be closely associated with patient prognosis, along with the biomarkers related to novel target or immune therapy. Evaluation of current literature regarding the prognostic stratification used in contemporary clinicopathological studies and progress in the development of targeted or immune therapy may help these patients benefit from tailored and personalized treatment and obtain better oncological results.

[The stratification of moisture content and its dynamics in co-composting of sewage sludge and pig manure].

PubMed

Luo, Wei; Chen, Tong-bin; Gao, Ding; Zheng, Yu-qi; Zheng, Guo-di

2004-03-01

The experiment of co-composting of sewage sludge and pig manure was studied. The moisture contents were 50.82%-60.87% at the stage of temperature rising and 38.7%-52.17% at the stage of thermophilic fermentation, and the stratification of moisture content were not obvious for both stages because the door, the internal wall and the depth of the composting bay had little effect on the stratification. At the stage of cooling, the moisture content was 24.54%-49.39%, and the stratification of moisture content was remarkable as the door, the internal wall and the depth of the composting bay had great influence on it. At the stage of maturity, the moisture content was 19.18%-49.34%, and the stratification of moisture weakened, for which the door and the internal wall were mainly responsible. At the different composting stage, the degree of difference of moisture content on the profiles of the pile was of the order: maturity stage > cooling stage > thermophilic stage = temperature rising stage, and the moisture content in the pile was as follows: the lower > the middle > the upper. The relation between moisture content and composting time meeted with two-order kinetics equation.

L'endométriose pariétale cicatricielle après césarienne: une entité rare

PubMed Central

El Fahssi, Mohammed; Lomdo, Massama; Bounaim, Ahmed; Ali, Abdelmounaim Ait; Sair, Khalid

2016-01-01

L'endométriose de la paroi est une entité clinique rare, dont la physiopathologie demeure imprécise. Elle survient le plus souvent après une intervention chirurgicale gynécologique ou obstétricale. Nous rapportons le cas d'une patiente présentant une douleur cyclique, au niveau de la cicatrice de césarienne, Avec à l'examen clinique une masse de 5cm localisée au niveau de la fosse iliaque droite. la tomodensitométrie montre une masse de densité tissulaire de 45mm de grand axe. D'où la décision d'excision large de la lésion dont l’étude anatomopathologique confirme le diagnostic d'endométriose pariétale. Les suites postopératoires étaient simples avec un recul de 20 mois sans récidive de la masse ni de la douleur. A travers notre cas, nous insisterons sur les caractéristiques de cette pathologie, ce qui permettra au praticien de comprendre l'intérêt du diagnostic et de la prise en charge précoce de cette affection ainsi que la possibilité de sa prévention au cours de chaque chirurgie gynécologique ou obstétricale. PMID:27642418

Stratification established by peeling detrainment from gravity currents: laboratory experiments and models

NASA Astrophysics Data System (ADS)

Hogg, Charlie; Dalziel, Stuart; Huppert, Herbert; Imberger, Jorg; Department of Applied Mathematics; Theoretical Physics Team; CentreWater Research Team

2014-11-01

Dense gravity currents feed fluid into confined basins in lakes, the oceans and many industrial applications. Existing models of the circulation and mixing in such basins are often based on the currents entraining ambient fluid. However, recent observations have suggested that uni-directional entrainment into a gravity current does not fully describe the mixing in such currents. Laboratory experiments were carried out which visualised peeling detrainment from the gravity current occurring when the ambient fluid was stratified. A theoretical model of the observed peeling detrainment was developed to predict the stratification in the basin. This new model gives a better approximation of the stratification observed in the experiments than the pre-existing entraining model. The model can now be developed such that it integrates into operational models of lakes.

Validating a Local Failure Risk Stratification for Use in Prospective Studies of Adjuvant Radiation Therapy for Bladder Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baumann, Brian C.; He, Jiwei; Hwang, Wei-Ting

Purpose: To inform prospective trials of adjuvant radiation therapy (adj-RT) for bladder cancer after radical cystectomy, a locoregional failure (LF) risk stratification was proposed. This stratification was developed and validated using surgical databases that may not reflect the outcomes expected in prospective trials. Our purpose was to assess sources of bias that may affect the stratification model's validity or alter the LF risk estimates for each subgroup: time bias due to evolving surgical techniques; trial accrual bias due to inclusion of patients who would be ineligible for adj-RT trials because of early disease progression, death, or loss to follow-up shortlymore » after cystectomy; bias due to different statistical methods to estimate LF; and subgrouping bias due to different definitions of the LF subgroups. Methods and Materials: The LF risk stratification was developed using a single-institution cohort (n=442, 1990-2008) and the multi-institutional SWOG 8710 cohort (n=264, 1987-1998) treated with radical cystectomy with or without chemotherapy. We evaluated the sensitivity of the stratification to sources of bias using Fine-Gray regression and Kaplan-Meier analyses. Results: Year of radical cystectomy was not associated with LF risk on univariate or multivariate analysis after controlling for risk group. By use of more stringent inclusion criteria, 26 SWOG patients (10%) and 60 patients from the single-institution cohort (14%) were excluded. Analysis of the remaining patients confirmed 3 subgroups with significantly different LF risks with 3-year rates of 7%, 17%, and 36%, respectively (P<.01), nearly identical to the rates without correcting for trial accrual bias. Kaplan-Meier techniques estimated higher subgroup LF rates than competing risk analysis. The subgroup definitions used in the NRG-GU001 adj-RT trial were validated. Conclusions: These sources of bias did not invalidate the LF risk stratification or substantially change the model's LF

Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions

DOE PAGES

Kodavasal, Janardhan; Lavoie, George A.; Assanis, Dennis N.; ...

2015-10-26

Full-cycle computational fluid dynamics simulations with gasoline chemical kinetics were performed to determine the impact of breathing and fuel injection strategies on thermal and compositional stratification, combustion and emissions during homogeneous charge compression ignition combustion. The simulations examined positive valve overlap and negative valve overlap strategies, along with fueling by port fuel injection and direct injection. The resulting charge mass distributions were analyzed prior to ignition using ignition delay as a reactivity metric. The reactivity stratification arising from differences in the distributions of fuel–oxygen equivalence ratio (Φ FO), oxygen molar fraction (χ O2) and temperature (T) was determined for threemore » parametric studies. In the first study, the reactivity stratification and burn duration for positive valve overlap valve events with port fuel injection and early direct injection were nearly identical and were dominated by wall-driven thermal stratification. nitrogen oxide (NO) and carbon monoxide (CO) emissions were negligible for both injection strategies. In the second study, which examined negative valve overlap valve events with direct injection and port fuel injection, reactivity stratification increased for direct injection as the Φ FO and T distributions associated with direct fuel injection into the hot residual gas were positively correlated; however, the latent heat absorbed from the hot residual gas by the evaporating direct injection fuel jet reduced the overall thermal and reactivity stratification. These stratification effects were offsetting, resulting in similar reactivity stratification and burn durations for the two injection strategies. The higher local burned gas temperatures with direct injection resulted in an order of magnitude increase in NO, while incomplete combustion of locally over-lean regions led to a sevenfold increase in CO emissions compared to port fuel injection. The final

Stratification of habitats for identifying habitat selection by Merriam's turkeys

Treesearch

Mark A. Rumble; Stanley H. Anderson

1992-01-01

Habitat selection patterns of Merriam’s Turkeys were compared in hierarchical analyses of three levels of habitat stratification. Habitat descriptions in first-level analyses were based on dominant species of vegetation. Habitat descriptions in second-level analyses were based on dominant species of vegetation and overstory canopy cover. Habitat descriptions in third-...

Picturing Sex Education: Notes on the Politics of Visual Stratification

ERIC Educational Resources Information Center

Janssen, Diederik F.

2006-01-01

This paper addresses the scarcity of research on depictions and layout in sex education materials. It is argued that pictures and layout can inform an analysis of social stratification based on visual access. This process of social organization is located using four theoretical models. However these models do not lend themselves to a close reading…

Risk Stratification Methods and Provision of Care Management Services in Comprehensive Primary Care Initiative Practices.

PubMed

Reddy, Ashok; Sessums, Laura; Gupta, Reshma; Jin, Janel; Day, Tim; Finke, Bruce; Bitton, Asaf

2017-09-01

Risk-stratified care management is essential to improving population health in primary care settings, but evidence is limited on the type of risk stratification method and its association with care management services. We describe risk stratification patterns and association with care management services for primary care practices in the Comprehensive Primary Care (CPC) initiative. We undertook a qualitative approach to categorize risk stratification methods being used by CPC practices and tested whether these stratification methods were associated with delivery of care management services. CPC practices reported using 4 primary methods to stratify risk for their patient populations: a practice-developed algorithm (n = 215), the American Academy of Family Physicians' clinical algorithm (n = 155), payer claims and electronic health records (n = 62), and clinical intuition (n = 52). CPC practices using practice-developed algorithm identified the most number of high-risk patients per primary care physician (282 patients, P = .006). CPC practices using clinical intuition had the most high-risk patients in care management and a greater proportion of high-risk patients receiving care management per primary care physician (91 patients and 48%, P =.036 and P =.128, respectively). CPC practices used 4 primary methods to identify high-risk patients. Although practices that developed their own algorithm identified the greatest number of high-risk patients, practices that used clinical intuition connected the greatest proportion of patients to care management services. © 2017 Annals of Family Medicine, Inc.

Microbial diversity and stratification of South Pacific abyssal marine sediments.

PubMed

Durbin, Alan M; Teske, Andreas

2011-12-01

Abyssal marine sediments cover a large proportion of the ocean floor, but linkages between their microbial community structure and redox stratification have remained poorly constrained. This study compares the downcore gradients in microbial community composition to porewater oxygen and nitrate concentration profiles in an abyssal marine sediment column in the South Pacific Ocean. Archaeal 16S rRNA clone libraries showed a stratified archaeal community that changed from Marine Group I Archaea in the aerobic and nitrate-reducing upper sediment column towards deeply branching, uncultured crenarchaeotal and euryarchaeotal lineages in nitrate-depleted, anaerobic sediment horizons. Bacterial 16S rRNA clone libraries revealed a similar shift on the phylum and subphylum level within the bacteria, from a complex community of Alpha-, Gamma- and Deltaproteobacteria, Actinobacteria and Gemmatimonadetes in oxic surface sediments towards uncultured Chloroflexi and Planctomycetes in the anaerobic sediment column. The distinct stratification of largely uncultured bacterial and archaeal groups within the oxic and nitrate-reducing marine sediment column provides initial constraints for their microbial habitat preferences. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Art & Astronomie - impressions celestes

NASA Astrophysics Data System (ADS)

Nazé, Yaël

2015-10-01

Ce livre revisite l'histoire de l'art dans ce qu'elle a de plus universel : son rapport au ciel. De l'Orient à l'Occident, de l'Antiquité à l'époque contemporaine, du classique au plus inattendu, il crée un espace singulier où se mêlent art et science, un musée imaginaire croisant sensibilité intime et compréhension du Cosmos, un jeu sans cesse réinventé...; car il n'y a pas une seule manière de regarder les étoiles. Bien sûr, le ciel possède un énorme pouvoir évocateur, une force inspiratrice à nulle autre pareille, mais l'inspiration n'est pas la seule des relations entre l'art et l'astronomie. En effet, les artistes peuvent apporter leur grain de sel aux révolutions scientifiques, tandis que l'astronomie peut aider à comprendre certaines œuvres. Avec près de 600 illustrations, cet ouvrage n'a pas pour but d'égrener la liste exhaustive des représentations de ciel étoilé, clair de lune, ambiance crépusculaire ou soleil de midi, mais plutôt d'aborder les multiples relations entre l'art et la science. Il s'agit d'une invitation à un voyage aux frontières mouvantes et incertaines des plus belles réalisations de l'esprit humain.

Risk stratification of thyroid nodules on ultrasonography with the French TI-RADS: description and reflections

PubMed Central

2016-01-01

The widespread use of ultrasonography places it in a key position for use in the risk stratification of thyroid nodules. The French proposal is a five-tier system, our version of a thyroid imaging reporting and database system (TI-RADS), which includes a standardized vocabulary and report and a quantified risk assessment. It allows the selection of the nodules that should be referred for fine-needle aspiration biopsies. Effort should be directed towards merging the different risk stratification systems utilized around the world and testing this unified system with multi-center studies. PMID:26324117

Une version franco-canadienne de la Physiotherapy Evidence Database (PEDro) Scale : L'Échelle PEDro

PubMed Central

Laroche, Chantal; Sutton, Anne; Guitard, Paulette; King, Judy; Poitras, Stéphane; Casimiro, Lynn; Tremblay, Manon; Cardinal, Dominique; Cavallo, Sabrina; Laferrière, Lucie; Grisé, Isabelle; Marshall, Lisa; Smith, Jacky R.; Lagacé, Josée; Pharand, Denyse; Galipeau, Roseline; Toupin-April, Karine; Loew, Laurianne; Demers, Catrine; Sauvé-Schenk, Katrine; Paquet, Nicole; Savard, Jacinthe; Tourigny, Jocelyne; Vaillancourt, Véronique

2015-01-01

RÉSUMÉ But : Effectuer une traduction franco-canadienne de la PEDro scale sous l'appellation proposée d'Échelle PEDro et examiner la validité de son contenu. Méthodologie : Nous avons utilisé une approche modifiée de la méthodologie de validation transculturelle de Vallerand. Une traduction renversée parallèle de la PEDro scale a d'abord été effectuée à la fois par des traductrices professionnelles et des chercheurs cliniciens. Ensuite, un premier comité d'experts (P1) a examiné les versions traduites et a créé la première version expérimentale de l'Échelle PEDro. Cette version a été évaluée par un deuxième comité d'experts (P2). Finalement, 32 chercheurs cliniques ont évalué cette deuxième version expérimentale de l'Échelle PEDro à l'aide d'une échelle de clarté (étendue de 5 points) et ont proposé les modifications finales. Résultats : Pour les différents énoncés de la version finale de l'Échelle PEDro, les moyennes sur l'échelle de clarté montrent un niveau élevé puisqu'elles varient entre 4,0 et 4,7 sur un score maximal de 5 points. Conclusion : Les quatre étapes rigoureuses du processus ont permis de produire une version franco-canadienne valide de l'Échelle PEDro. PMID:26839449

Numerical investigation of potential stratification caused by a cryogenic helium spill inside a tunnel

NASA Astrophysics Data System (ADS)

Sinclair, Cameron; Malecha, Ziemowit; Jedrusyna, Artur

2018-04-01

The sudden release of cryogenic fluid into an accelerator tunnel can pose a significant health and safety risk. For this reason, it is important to evaluate the consequences of such a spill. Previous publications concentrated on either Oxygen Deficiency Hazard or the evaluation of mathematical models using experimental data. No studies to date have focussed on the influence of cryogen inlet conditions on flow development. In this paper, the stratification behaviour of low-temperature helium released into an air-filled accelerator tunnel is investigated for varying helium inlet diameters. A numerical model was constructed using the OpenFOAM Toolbox of a generalised 3D geometry, with similar hydraulic characteristics to the CERN and SLAC tunnels. This model has been validated against published experimental and numerical data. A dimensionless parameter, based on Bakke number, was then determined for the onset of stratification, taking into account the helium inlet diameter; a dimensionless parameter for the degree of stratification was also employed. The simulated flow behaviour is described in terms of these dimensionless parameters, as well as the temperature and oxygen concentration at various heights throughout the tunnel.

Fine-scale patterns of population stratification confound rare variant association tests.

PubMed

O'Connor, Timothy D; Kiezun, Adam; Bamshad, Michael; Rich, Stephen S; Smith, Joshua D; Turner, Emily; Leal, Suzanne M; Akey, Joshua M

2013-01-01

Advances in next-generation sequencing technology have enabled systematic exploration of the contribution of rare variation to Mendelian and complex diseases. Although it is well known that population stratification can generate spurious associations with common alleles, its impact on rare variant association methods remains poorly understood. Here, we performed exhaustive coalescent simulations with demographic parameters calibrated from exome sequence data to evaluate the performance of nine rare variant association methods in the presence of fine-scale population structure. We find that all methods have an inflated spurious association rate for parameter values that are consistent with levels of differentiation typical of European populations. For example, at a nominal significance level of 5%, some test statistics have a spurious association rate as high as 40%. Finally, we empirically assess the impact of population stratification in a large data set of 4,298 European American exomes. Our results have important implications for the design, analysis, and interpretation of rare variant genome-wide association studies.

Grossesses extra utérines successives et bilharziose tubaire chez une touriste française

PubMed Central

Laroche, Justine; Mottet, Nicolas; Malincenco, Marianna; Gay, Catherine; Royer, Pierre Yves; Riethmuller, Didier

2016-01-01

La bilharziose est la seconde endémie parasitaire mondiale et ses atteintes génito urinaires sont bien décrites. Les grossesses ectopiques (GEU) sur obstruction tubaire par les œufs de bilharziose sont rapportées dans les populations africaines. La bilharziose affecte aussi les voyageurs mais l'atteinte de l'appareil génital féminin est plus rare. Nous rapportons un cas exceptionnel de deux GEU successives sur bilharziose tubaire chez une patiente d'origine Française, sept ans après un voyage touristique au Mali, la première découverte sur pièce de salpingectomie et la seconde ayant nécessité une salpingotomie controlatérale avec une injection de méthotrexate, deux mois plus tard. PMID:27200124

Thermal advection and stratification effects on surface winds and the low level meridional mass transport

NASA Technical Reports Server (NTRS)

Levy, Gad; Tiu, Felice S.

1990-01-01

Statistical tests are performed on the Seasat scatterometer observations to examine if and to what degree thermal advection and stratification effects manifest themselves in these remotely sensed measurements of mean wind and wind stress over the ocean. On the basis of a two layer baroclinic boundary layer model which is presented, it is shown that the thermal advection and stratification of the entire boundary layer as well as the geostrophic forcing influence the modeled near surface wind and wind stress profiles. Evidence of diurnal variation in the stratification under barotropic conditions is found in the data, with the daytime marine boundary layer being more convective than its nighttime counterpart. The temporal and spacial sampling pattern of the satellite makes it impossible to recover the full diurnal cycle, however. The observed effects of the thermal advection are shown to be statistically significant during the day (and presumed more convective) hours, causing a systematic increase in the poleward transport of mass and heat. The statistical results are in a qualitative agreement with the model simulations and cannot be reproduced in randomized control tests.

AKT1 provides an essential survival signal required for differentiation and stratification of primary human keratinocytes.

PubMed

Thrash, Barry R; Menges, Craig W; Pierce, Robert H; McCance, Dennis J

2006-04-28

Keratinocyte differentiation and stratification are complex processes involving multiple signaling pathways, which convert a basal proliferative cell into an inviable rigid squame. Loss of attachment to the basement membrane triggers keratinocyte differentiation, while in other epithelial cells, detachment from the extracellular matrix leads to rapid programmed cell death or anoikis. The potential role of AKT in providing a survival signal necessary for stratification and differentiation of primary human keratinocytes was investigated. AKT activity increased during keratinocyte differentiation and was attributed to the specific activation of AKT1 and AKT2. Targeted reduction of AKT1 expression, but not AKT2, by RNA interference resulted in an abnormal epidermis in organotypic skin cultures with a thin parabasal region and a pronounced but disorganized cornified layer. This abnormal stratification was due to significant cell death in the suprabasal layers and was alleviated by caspase inhibition. Normal expression patterns of both early and late markers of keratinocyte differentiation were also disrupted, producing a poorly developed stratum corneum.

Urothelial cancer of the upper urinary tract: emerging biomarkers and integrative models for risk stratification.

PubMed

Mathieu, Romain; Vartolomei, Mihai D; Mbeutcha, Aurélie; Karakiewicz, Pierre I; Briganti, Alberto; Roupret, Morgan; Shariat, Shahrokh F

2016-08-01

The aim of this review was to provide an overview of current biomarkers and risk stratification models in urothelial cancer of the upper urinary tract (UTUC). A non-systematic Medline/PubMed literature search was performed using the terms "biomarkers", "preoperative models", "postoperative models", "risk stratification", together with "upper tract urothelial carcinoma". Original articles published between January 2003 and August 2015 were included based on their clinical relevance. Additional references were collected by cross referencing the bibliography of the selected articles. Various promising predictive and prognostic biomarkers have been identified in UTUC thanks to the increasing knowledge of the different biological pathways involved in UTUC tumorigenesis. These biomarkers may help identify tumors with aggressive biology and worse outcomes. Current tools aim at predicting muscle invasive or non-organ confined disease, renal failure after radical nephroureterectomy and survival outcomes. These models are still mainly based on imaging and clinicopathological feature and none has integrated biomarkers. Risk stratification in UTUC is still suboptimal, especially in the preoperative setting due to current limitations in staging and grading. Identification of novel biomarkers and external validation of current prognostic models may help improve risk stratification to allow evidence-based counselling for kidney-sparing approaches, perioperative chemotherapy and/or risk-based surveillance. Despite growing understanding of the biology underlying UTUC, management of this disease remains difficult due to the lack of validated biomarkers and the limitations of current predictive and prognostic tools. Further efforts and collaborations are necessaryry to allow their integration in daily practice.

Generalized scaling of seasonal thermal stratification in lakes

NASA Astrophysics Data System (ADS)

Shatwell, T.; Kirillin, G.

2016-12-01

The mixing regime is fundamental to the biogeochemisty and ecology of lakes because it determines the vertical transport of matter such as gases, nutrients, and organic material. Whereas shallow lakes are usually polymictic and regularly mix to the bottom, deep lakes tend to stratify seasonally, separating surface water from deep sediments and deep water from the atmosphere. Although empirical relationships exist to predict the mixing regime, a physically based, quantitative criterion is lacking. Here we review our recent research on thermal stratification in lakes at the transition between polymictic and stratified regimes. Using the mechanistic balance between potential and kinetic energy in terms of the Richardson number, we derive a generalized physical scaling for seasonal stratification in a closed lake basin. The scaling parameter is the critical mean basin depth that delineates polymictic and seasonally stratified lakes based on lake water transparency (Secchi depth), lake length, and an annual mean estimate for the Monin-Obukhov length. We validated the scaling on available data of 374 global lakes using logistic regression and found it to perform better than other criteria including a conventional open basin scaling or a simple depth threshold. The scaling has potential applications in estimating large scale greenhouse gas fluxes from lakes because the required inputs, like water transparency and basin morphology, can be acquired using the latest remote sensing technologies. The generalized scaling is universal for freshwater lakes and allows the seasonal mixing regime to be estimated without numerically solving the heat transport equations.

Inference for Environmental Intervention Studies using Principal Stratification

PubMed Central

Hackstadt, A. J.; Butz, Arlene M.; Williams, D’Ann L.; Diette, Gregory B.; Breysse, Patrick N.; Matsui, Elizabeth C.; Peng, Roger D.

2014-01-01

Previous research has found evidence of an association between indoor air pollution and asthma morbidity in children. Environmental intervention studies have been performed to examine the role of household environmental interventions in altering indoor air pollution concentrations and improving health. Previous environmental intervention studies have found only modest effects on health outcomes and it is unclear if the health benefits provided by environmental modification are comparable to those provided by medication. Traditionally, the statistical analysis of environmental intervention studies has involved performing two intention-to-treat analyses that separately estimate the effect of the environmental intervention on health and the effect of the environmental intervention on indoor air pollution concentrations. We propose a principal stratification (PS) approach to examine the extent to which an environmental intervention’s effect on health outcomes coincides with its effect on indoor air pollution. We apply this approach to data from a randomized air cleaner intervention trial conducted in a population of asthmatic children living in Baltimore, Maryland, USA. We find that amongst children for whom the air cleaner reduced indoor particulate matter concentrations, the intervention resulted in a meaningful improvement of asthma symptoms with an effect generally larger than previous studies have shown. A key benefit of using principal stratification in environmental intervention studies is that it allows investigators to estimate causal effects of the intervention for sub-groups defined by changes in the indoor air pollution concentration. PMID:25164949

Inference for environmental intervention studies using principal stratification.

PubMed

Hackstadt, Amber J; Matsui, Elizabeth C; Williams, D'Ann L; Diette, Gregory B; Breysse, Patrick N; Butz, Arlene M; Peng, Roger D

2014-12-10

Previous research has found evidence of an association between indoor air pollution and asthma morbidity in children. Environmental intervention studies have been performed to examine the role of household environmental interventions in altering indoor air pollution concentrations and improving health. Previous environmental intervention studies have found only modest effects on health outcomes and it is unclear if the health benefits provided by environmental modification are comparable with those provided by medication. Traditionally, the statistical analysis of environmental intervention studies has involved performing two intention-to-treat analyses that separately estimate the effect of the environmental intervention on health and the effect of the environmental intervention on indoor air pollution concentrations. We propose a principal stratification approach to examine the extent to which an environmental intervention's effect on health outcomes coincides with its effect on indoor air pollution. We apply this approach to data from a randomized air cleaner intervention trial conducted in a population of asthmatic children living in Baltimore, Maryland, USA. We find that among children for whom the air cleaner reduced indoor particulate matter concentrations, the intervention resulted in a meaningful improvement of asthma symptoms with an effect generally larger than previous studies have shown. A key benefit of using principal stratification in environmental intervention studies is that it allows investigators to estimate causal effects of the intervention for sub-groups defined by changes in the indoor air pollution concentration. Copyright © 2014 John Wiley & Sons, Ltd.

How Global Academic Stratification Affects Local Academies: The Inflated Role of Knowledge Reception in the Philosophy Discipline in Modern Japan

ERIC Educational Resources Information Center

Chew, Matthew M.

2008-01-01

Sociologists of knowledge find that academic stratification is present among individual scholars, genders, networks, fields, and all kinds of scientific organizations, while communications scholars have been studying global cultural asymmetry for a long time. Yet few researchers have explored the global dimension of academic stratification. In…

Intrabreed Stratification Related to Divergent Selection Regimes in Purebred Dogs May Affect the Interpretation of Genetic Association Studies

PubMed Central

Chang, Melanie L.; Yokoyama, Jennifer S.; Branson, Nick; Dyer, Donna J.; Hitte, Christophe; Overall, Karen L.

2009-01-01

Until recently, canine genetic research has not focused on population structure within breeds, which may confound the results of case–control studies by introducing spurious correlations between phenotype and genotype that reflect population history. Intrabreed structure may exist when geographical origin or divergent selection regimes influence the choices of potential mates for breeding dogs. We present evidence for intrabreed stratification from a genome-wide marker survey in a sample of unrelated dogs. We genotyped 76 Border Collies, 49 Australian Shepherds, 17 German Shepherd Dogs, and 17 Portuguese Water Dogs for our primary analyses using Affymetrix Canine v2.0 single-nucleotide polymorphism (SNP) arrays. Subsets of autosomal markers were examined using clustering algorithms to facilitate assignment of individuals to populations and estimation of the number of populations represented in the sample. SNPs passing stringent quality control filters were employed for explicitly phylogenetic analyses reconstructing relationships between individuals using maximum parsimony and Bayesian methods. We used simulation studies to explore the possible effects of intrabreed stratification on genome-wide association studies. These analyses demonstrate significant stratification in at least one of our primary breeds of interest, the Border Collie. Demographic and pedigree data suggest that this population substructure may result from geographic isolation or divergent selection regimes practiced by breeders with different breeding program goals. Simulation studies indicate that such stratification could result in false discovery rates significant enough to confound genome-wide association analyses. Intrabreed stratification should be accounted for when designing and interpreting the results of case–control association studies using purebred dogs.

Insuffisance rénale aigüe: présentation rare d’une maladie d’Addison

PubMed Central

Salhi, Houda

2016-01-01

La maladie d’Addison est une pathologie rare, qui se manifeste fréquemment par des signes cliniques non spécifiques. Ce qui peut causer un retard diagnostic et thérapeutique. Cette maladie peut se présenter comme un tableau d’insuffisance rénale aigue. Nous rapportons le cas d’un patient présentant une maladie d’Addison qui a été pris en charge initialement comme une insuffisance rénale aigue secondaire à un myélome multiple et dont le diagnostic a été redressé par la suite. Le patient s’est spectaculairement amélioré après mis en place de traitement par réhydratation par voie intraveineuse; hydrocortisone injectable. PMID:27800088

Métastase pleurale et pulmonaire d’une polyadénofibromatose dégénéréé: à propos d’un cas

PubMed Central

El Hachimi, Kawtar; Benjelloun, Hanane; Zaghba, Nahid; Yassine, Najiba

2017-01-01

La polyadénofibromatose ou l’adénofibromatose est définie par la présence d’au moins 3 adénofibromes, uni ou bilatéraux atteignant une taille importante responsable de troubles trophiques. Nous rapportons une observation colligée au service des maladies respiratoires du Centre Hospitalier Universitaire Ibn Rochd de Casablanca. Il s’agit d’une patiente âgée de 46ans, suivie depuis l’âge de 30 ans pour une adénofibromatose bilatérale opérée à 4 reprises. Suite à un bilan préopératoire d’une mastectomie bilatérale, une radio du thorax a été réalisée objectivant un hémithorax droit opaque avec refoulement des éléments du médiastin. L’examen clinique retrouvait un syndrome d’épanchement liquidien de l’hémithorax droit et une adénopathie cervicale sus claviculaire gauche. La ponction biopsie pleurale confirmait la localisation pleurale d’un carcinome peu différencié et invasif compatible avec une origine mammaire. La bronchoscopie après évacuation pleurale objectivait un aspect infiltré de tout l’arbre bronchique, dont les biopsies concluaient au même résultat anatomopathologique. Le traitement préconisé était une polychimiothérapie. L’évolution était marquée par l’apparition de métastases hépatiques. A travers cette observation, nous concluons que les adénofibromes nécessitent une surveillance régulière vu le risque de dégénérescence vers le cancer du sein qui est une cause fréquente de métastases pleuropulmonaires. PMID:29515733

Turbulent Control Of The Ocean Surface Boundary Layer During The Onset Of Seasonal Stratification

NASA Astrophysics Data System (ADS)

Palmer, M.; Hopkins, J.; Wihsgott, J. U.

2016-02-01

To provide accurate predictions of global carbon cycles we must first understand the mechanistic control of ocean surface boundary layer (OSBL) temperature and the timing and depth of ocean thermal stratification, which are critical controls on oceanic carbon sequestration via the solubility and biological pumps. Here we present an exciting new series of measurements of the fine-scale physical structure and dynamics of the OSBL that provide fresh insight into the turbulent control of upper ocean structure. This study was made in the centre of the Celtic Sea, a broad section of the NW European continental shelf, and represents one of only a handful of measurements of near-surface turbulence in our shelf seas. Data are provided by an ocean microstructure glider (OMG) that delivers estimates of turbulent dissipation rates and mixing from 100m depth to within 2-3m of the sea surface, approximately every 10 minutes and continually for 21 days during April 2015. The OMG successfully captures the onset of spring stratification as solar radiation finally overcomes the destabilising effects of turbulent surface processes. Using coincident meteorological and wave observations from a nearby mooring, and full water column current velocity data we are able to close the near surface energy budget and provide a valuable test for proposed parameterisations of OSBL turbulence based on wind, wave and buoyancy inputs. We verify recent hypotheses that even very subtle thermal stratification, below often assumed limits of 0.1°C, are sufficient to establish sustained stratification even during active surface forcing. We also find that while buoyant production (convection) is not an efficient mechanism for mixing beyond the base of the mixed layer it does play an important role in modification of surface structure, acting to precondition the OSBL for enhanced (deeper) impacts from wind and wave driven turbulence.

Risk Stratification and Shared Decision Making for Colorectal Cancer Screening: A Randomized Controlled Trial.

PubMed

Schroy, Paul C; Duhovic, Emir; Chen, Clara A; Heeren, Timothy C; Lopez, William; Apodaca, Danielle L; Wong, John B

2016-05-01

Eliciting patient preferences within the context of shared decision making has been advocated for colorectal cancer (CRC) screening, yet providers often fail to comply with patient preferences that differ from their own. To determine whether risk stratification for advanced colorectal neoplasia (ACN) influences provider willingness to comply with patient preferences when selecting a desired CRC screening option. Randomized controlled trial. Asymptomatic, average-risk patients due for CRC screening in an urban safety net health care setting. Patients were randomized 1:1 to a decision aid alone (n= 168) or decision aid plus risk assessment (n= 173) arm between September 2012 and September 2014. The primary outcome was concordance between patient preference and test ordered; secondary outcomes included patient satisfaction with the decision-making process, screening intentions, test completion rates, and provider satisfaction. Although providers perceived risk stratification to be useful in selecting an appropriate screening test for their average-risk patients, no significant differences in concordance were observed between the decision aid alone and decision aid plus risk assessment groups (88.1% v. 85.0%,P= 0.40) or high- and low-risk groups (84.5% v. 87.1%,P= 0.51). Concordance was highest for colonoscopy and relatively low for tests other than colonoscopy, regardless of study arm or risk group. Failure to comply with patient preferences was negatively associated with satisfaction with the decision-making process, screening intentions, and test completion rates. Single-institution setting; lack of provider education about the utility of risk stratification into their decision making. Providers perceived risk stratification to be useful in their decision making but often failed to comply with patient preferences for tests other than colonoscopy, even among those deemed to be at low risk of ACN. © The Author(s) 2016.

Conception, fabrication et validation d'une presse a injection basse pression pour le procede des poudres metalliques =

NASA Astrophysics Data System (ADS)

Lamarre, Simon G.

Le moulage par injection a basse pression de poudre metallique est une technique de mise en forme de pieces de formes complexes. La poudre metallique est melangee avec des polymeres basse viscosite (ex. : cire) pour former un melange homogene a une temperature superieure a la temperature de fusion des polymeres. Pour faciliter l'injection dans la cavite du moule, la composition des melanges est ajustee pour diminuer la viscosite. D'une part, les melanges peu visqueux possedent une bonne moulabilite. D'autre part, le phenomene de la segregation se manifeste rapidement avec les melanges peu visqueux. Les machines commerciales sont munies d'un canal d'injection et d'une valve qui relient le reservoir de melange et la cavite du moule. Le melange reste stationnaire dans ces composantes entre deux sequences d'injection, ce qui le rend propice a la segregation. Plusieurs brevets tentent de resoudre ce probleme en utilisant des pompes et des canaux de recirculation. Ces composantes sont difficiles a nettoyer en raison de leur complexite. Une machine a injection basse pression a ete concue et fabriquee pour l'etude de l'aptitude au moulage des melanges de tres faible viscosite (ex. : 0.1 Pa˙s), qui tient compte du phenomene de segregation et des contraintes de nettoyage. Un piston d'injection puise le volume desire d'un reservoir. Ensuite, un mouvement lateral cisaille le melange a l'intersection entre le reservoir et le cylindre et bouche l'orifice de sortie du reservoir. Le cylindre est degage et peut recevoir le moule. A la suite de l'injection, le piston retourne a la position du reservoir et entre dans son orifice de sortie. Le melange residuel est retourne dans le reservoir, melange et desaere a nouveau. L'appareil a ete valide par des essais d'injectabilite avec un melange de poudre d'acier inoxydable et de liants a basse viscosite. Des essais d'injection ont montre que le melange contenant l'acide stearique a parcouru la plus grande distance dans le moule de forme

Variabilite temporelle des naines T et construction d'une camera infrarouge a grand champ

NASA Astrophysics Data System (ADS)

Artigau, Etienne

Le travail de thèse décrit ici se divise en deux sections distinctes: la première porte sur une étude de la variabilité temporelle des naines T et la seconde sur la construction et les performances de la Caméra PAnoramique Proche InfraRouge (CPAPIR). Les naines brunes sont des objets qui se forment comme les étoiles, lors de l'effondrement gravitationnel d'un nuage de gaz moléculaire, mais dont la masse est trop faible pour leur permettre d'entretenir des réactions de fusion nucléaire. Environ 70% des naines brunes de type L, qui ont des températures comprises entre 2200 K et 1500 K, présentent une variabilité temporelle dont les mécanismes exacts font toujours l'objet de débats. Nous avons étendu la recherche de variabilité temporelle aux naines brunes ayant des températures inférieures à ~1500 K et qui présentent les signatures du méthane, soit les naines T. Nos observations menées à l'Observatoire du mont Mégantic montrent qu'une fraction importante des naines T sont variables à 1.2 mm et 1.6 mm à des niveaux allant de 17 mmag à 53 mmag RMS. Les propriétés photométriques de cette variabilité sont consistantes avec une évolution de la couverture de nuages de poussière à la surface de plusieurs naines T. Des observations complémentaires menées en spectroscopie au télescope Canada-France-Hawaii montrent, pour une naine T, une variabilité spectroscopique dans le proche infrarouge qui est aussi consistante avec l'évolution de tels nuages de poussière. CPAPIR est une caméra infrarouge con=E7ue pour être utilisée à l'Observatoire du mont Mégantic. Elle possède un champ de 30' × 30', soit le plus grand champ de vue parmi les caméras infrarouges astronomiques actuellement en service. CPAPIR est équipé d'un détecteur de type Hawaii-II sensible de 0.8 mm à 2.4 mm avec 2048×2048 pixels. L'optique cryogénique de CPAPIR comprend 8 lentilles cryogéniques et 10 filtres disposés dans deux roues à filtres. Les observations

Post-stratification sampling in small area estimation (SAE) model for unemployment rate estimation by Bayes approach

NASA Astrophysics Data System (ADS)

Hanike, Yusrianti; Sadik, Kusman; Kurnia, Anang

2016-02-01

This research implemented unemployment rate in Indonesia that based on Poisson distribution. It would be estimated by modified the post-stratification and Small Area Estimation (SAE) model. Post-stratification was one of technique sampling that stratified after collected survey data. It's used when the survey data didn't serve for estimating the interest area. Interest area here was the education of unemployment which separated in seven category. The data was obtained by Labour Employment National survey (Sakernas) that's collected by company survey in Indonesia, BPS, Statistic Indonesia. This company served the national survey that gave too small sample for level district. Model of SAE was one of alternative to solved it. According the problem above, we combined this post-stratification sampling and SAE model. This research gave two main model of post-stratification sampling. Model I defined the category of education was the dummy variable and model II defined the category of education was the area random effect. Two model has problem wasn't complied by Poisson assumption. Using Poisson-Gamma model, model I has over dispersion problem was 1.23 solved to 0.91 chi square/df and model II has under dispersion problem was 0.35 solved to 0.94 chi square/df. Empirical Bayes was applied to estimate the proportion of every category education of unemployment. Using Bayesian Information Criteria (BIC), Model I has smaller mean square error (MSE) than model II.

Zombie Vortex Instability: Effects of Non-uniform Stratification & Thermal Cooling

NASA Astrophysics Data System (ADS)

Barranco, Joseph; Pei, Suyang; Marcus, Phil; Jiang, Chung-Hsiang

2015-11-01

The Zombie Vortex Instability (ZVI) is a nonlinear instability in rotating, stratified, shear flows, such as in protoplanetary disks (PPD) of gas and dust orbiting new stars. The instability mechanism is the excitation of baroclinic critical layers, leading to vorticity amplification and nonlinear evolution into anticyclonic vortices and cyclonic sheets. ZVI is most robust when the Coriolis frequency, shear rate, and Brunt-Väisälä (BV) frequency are of the same order. Previously, we investigated ZVI with uniform stratification and without thermal cooling. Here, we explore the role of non-uniform stratification as would be found in PPDs in which the BV frequency is zero in the disk midplane, and increases away from the midplane. We find that ZVI is vigorous 1-3 pressure scale heights away from the midplane, but the non-isotropic turbulence generated by ZVI can penetrate into the midplane. We also explore the effect of thermal cooling and find that ZVI is still robust for cooling times as short as 5 orbital periods. ZVI may play important roles in transporting angular momentum in PPDs, and in trapping dust grains, which may trigger gravitational clumping into planetesimals.

Spatial and Temporal Trends in the Density Stratification of Long Island Sound

NASA Astrophysics Data System (ADS)

Marchese, P.

2017-12-01

The density structure of Long Island Sound (LIS) was studied using historical hydrographic data. Like many estuaries, LIS suffers from hypoxia during the summer months; a result of the density stratification caused by surface warming and weak wind conditions. In summer, the water column is stratified at both ends (east and west) with a vertically well mixed region near the middle. During these months, the western side of LIS experiences low bottom dissolved from the higher nutrient influx and the resulting oxygen demand. Eastern LIS does not experience hypoxia despite sometimes being more highly stratified than the west because these bottom water are regularly ventilated by incoming higher DO water from outside. Topography and density gradients prevent the low DO water from encroaching to the eastern basin. In the fall, changing atmospheric conditions weakens the density stratification throughout LIS, although in some regions the vertical gradient will persist, sometimes until January.

Prostate cancer: predicting high-risk prostate cancer-a novel stratification tool.

PubMed

Buck, Jessica; Chughtai, Bilal

2014-05-01

Currently, numerous systems exist for the identification of high-risk prostate cancer, but few of these systems can guide treatment strategies. A new stratification tool that uses common diagnostic factors can help to predict outcomes after radical prostatectomy. The tool aids physicians in the identification of appropriate candidates for aggressive, local treatment.

Immigrants and Wealth Stratification in the U.S. JCPR Working Paper.

ERIC Educational Resources Information Center

Hao, Lingxin

This study examines the importance of including immigrants in studies of wealth stratification by race/ethnicity, using data from the 1992 and 1993 panels of the Survey of Income and Program Participation. It addresses the uniqueness of immigrants using descriptive and multivariate analyses by constructing a measure of wealth age that considers…

Observations of Tidal Straining Within Two Different Ocean Environments in the East China Sea: Stratification and Near-Bottom Turbulence

NASA Astrophysics Data System (ADS)

Yang, Wei; Wei, Hao; Zhao, Liang

2017-11-01

Tidal straining describes the straining effect induced by the vertical shear of oscillatory tidal currents that act on horizontal density gradients. It tends to create tidal periodic stratification and modulate the turbulence in the bottom boundary layer (BBL). Here, we present observations of current, hydrology and turbulence obtained at two mooring stations that are characterized by two typical hydrological environments in the East China Sea (ECS). One is located adjacent to the Changjiang River's mouth, and the other is located over a sloping shelf which is far from the freshwater sources. Tidal straining induces a semidiurnal switching between stable and unstable stratification at both stations. Near-bottom high-frequency velocity measurements further reveal that the dissipation rate of turbulent kinetic energy (TKE) is highly elevated during periods when unstable stratification occurs. A comparison between the TKE dissipation rate (ɛ) and the shear production (P) further reveals that the near-bottom mixing is locally shear-induced most of the time except during the unstable stratification period. Within this period, the magnitude of dissipation exceeds the expected value based on the law of the wall by an order of magnitude. The buoyancy flux that calculated by the balance method is too small to compensate for the existing discrepancy between the dissipation and shear production. Another plausible candidate is the advection of TKE, which may play an important role in the TKE budget during the unstable stratification period.

The relationship between social stratification and all-cause mortality among children in the United States: 1968-1992.

PubMed

DiLiberti, J H

2000-01-01

US childhood poverty rates have increased for most of the past 2 decades. Although overall mortality among children has apparently fallen during this interval, these aggregate mortality rates may hide a disproportionate burden imposed on the least advantaged. This study assessed the impact of social stratification on long-term US childhood mortality rates and examined the temporal relationship between mortality attributable to social stratification and childhood poverty rates. Using US childhood mortality data obtained from the Compressed Mortality File (National Center for Health Statistics) and a county-level measure of social stratification (residential telephone availability), I evaluated the impact of social stratification on long-term trends (1968-1992) in age-adjusted mortality and compared the resulting attributable proportions to trends in childhood poverty rates. Between 1968 and 1987 the proportion of US childhood deaths attributable to social stratification decreased from.22 to.17. Subsequently, it increased to.24 in 1992, despite continuous declines in overall childhood mortality rates. These proportions correlated strongly with earlier childhood poverty rates, taking into account an apparent 9-year lag. Among black children comparable trends were not observed, although throughout this time period their mortality rates were far higher than among the rest of the population and declined more slowly. Despite declining childhood mortality rates between 1968 and 1992, children living in the least advantaged counties continued to die at higher rates than those living in the most advantaged counties. This differential worsened considerably after 1987, and by 1992 had a substantive impact on US life expectancy at birth, resulting in perhaps the most significant (in terms of years of life lost) reversal in the health of the US public in the 20th century.

Vertical Stratification of Soil Phosphorus as a Concern for Dissolved Phosphorus Runoff in the Lake Erie Basin.

PubMed

Baker, David B; Johnson, Laura T; Confesor, Remegio B; Crumrine, John P

2017-11-01

During the re-eutrophication of Lake Erie, dissolved reactive phosphorus (DRP) loading and concentrations to the lake have nearly doubled, while particulate phosphorus (PP) has remained relatively constant. One potential cause of increased DRP concentrations is P stratification, or the buildup of soil-test P (STP) in the upper soil layer (<5 cm). Stratification often accompanies no-till and mulch-till practices that reduce erosion and PP loading, practices that have been widely implemented throughout the Lake Erie Basin. To evaluate the extent of P stratification in the Sandusky Watershed, certified crop advisors were enlisted to collect stratified soil samples (0-5 or 0-2.5 cm) alongside their normal agronomic samples (0-20 cm) ( = 1758 fields). The mean STP level in the upper 2.5 cm was 55% higher than the mean of agronomic samples used for fertilizer recommendations. The amounts of stratification were highly variable and did not correlate with agronomic STPs (Spearman's = 0.039, = 0.178). Agronomic STP in 70% of the fields was within the buildup or maintenance ranges for corn ( L.) and soybeans [ (L.) Merr.] (0-46 mg kg Mehlich-3 P). The cumulative risks for DRP runoff from the large number of fields in the buildup and maintenance ranges exceeded the risks from fields above those ranges. Reducing stratification by a one-time soil inversion has the potential for larger and quicker reductions in DRP runoff risk than practices related to drawing down agronomic STP levels. Periodic soil inversion and mixing, targeted by stratified STP data, should be considered a viable practice to reduce DRP loading to Lake Erie. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Virtual Mobility in Higher Education. The UNED Campus Net Program

ERIC Educational Resources Information Center

Aguado, Teresa; Monge, Fernando; Del Olmo, Alicia

2014-01-01

We present the UNED Virtual Mobility Campus Net Program, implemented since 2012 in collaboration with European and Latin American universities. Program's objectives, participating institutions, procedures, and evaluation are exposed. Virtual mobility is understood as a meaningful strategy for intercultural learning by studying an undergraduate or…

A role for jasmonates in the release of dormancy by cold stratification in wheat

PubMed Central

Xu, Qian; Truong, Thy T.; Barrero, Jose M.; Jacobsen, John V.; Hocart, Charles H.; Gubler, Frank

2016-01-01

Hydration at low temperatures, commonly referred to as cold stratification, is widely used for releasing dormancy and triggering germination in a wide range of species including wheat. However, the molecular mechanism that underlies its effect on germination has largely remained unknown. Our previous studies showed that methyl-jasmonate, a derivative of jasmonic acid (JA), promotes dormancy release in wheat. In this study, we found that cold-stimulated germination of dormant grains correlated with a transient increase in JA content and expression of JA biosynthesis genes in the dormant embryos after transfer to 20 oC. The induction of JA production was dependent on the extent of cold imbibition and precedes germination. Blocking JA biosynthesis with acetylsalicylic acid (ASA) inhibited the cold-stimulated germination in a dose-dependent manner. In addition, we have explored the relationship between JA and abscisic acid (ABA), a well-known dormancy promoter, in cold regulation of dormancy. We found an inverse relationship between JA and ABA content in dormant wheat embryos following stratification. ABA content decreased rapidly in response to stratification, and the decrease was reversed by addition of ASA. Our results indicate that the action of JA on cold-stratified grains is mediated by suppression of two key ABA biosynthesis genes, TaNCED1 and TaNCED2. PMID:27140440

Pneumonie organisée révélatrice d'une polymyosite

PubMed Central

Ben Saad, Ahmed; Joobeur, Samah; Rouetbi, Naceur; Mhamed, Saousen Cheikh; Skhiri, Néji; Mribah, Hathami; El Kamel, Ali

2014-01-01

Les polymyosites (PM) sont des connectivites très rares, d’étiologie inconnue, dotées d'un grand polymorphisme clinique et évolutif. Elles peuvent être associées à d'autres manifestations viscérales notamment pulmonaires telles que la pneumopathie interstitielle. Ces complications respiratoires sont souvent associées à un taux de mortalité élevé. Les cas de pneumonie organisée révélatrice de polymyosite sont rarement rapportés dans la littérature et de description récente. Nous rapportons l'observation d'une patiente âgée de 53 ans qui a présenté, 14 mois après avoir porter le diagnostic d'une pneumonie organisée, des myalgies diffuses, un ‘dème des membres inférieurs et une élévation des enzymes musculaires. La biopsie musculaire a confirmé le diagnostic de la myosite. L’évolution était favorable sous corticothérapie. Le traitement de la PO associée au PM n'est pas clairement établi. La corticothérapie constitue le traitement de première intention. PMID:25722789

Stable density stratification solar pond

NASA Technical Reports Server (NTRS)

Lansing, F. L. (Inventor)

1985-01-01

A stable density-stratification solar pond for use in the collection and storage of solar thermal energy including a container having a first section characterized by an internal wall of a substantially cylindrical configuration and a second section having an internal wall of a substantially truncated conical configuration surmounting the first section in coaxial alignment therewith, the second section of said container being characterized by a base of a diameter substantially equal to the diameter of the first section and a truncated apex defining a solar energy acceptance opening is discussed. A body of immiscible liquids is disposed within the container and comprises a lower portion substantially filling the first section of the container and an upper portion substantially filling the second section of the container, said lower portion being an aqueous based liquid of a darker color than the upper portion and of a greater density. A protective cover plate is removably provided for covering the acceptance opening.

Dissolved oxygen stratification and response to thermal structure and long-term climate change in a large and deep subtropical reservoir (Lake Qiandaohu, China).

PubMed

Zhang, Yunlin; Wu, Zhixu; Liu, Mingliang; He, Jianbo; Shi, Kun; Zhou, Yongqiang; Wang, Mingzhu; Liu, Xiaohan

2015-05-15

From January 2010 to March 2014, detailed depth profiles of water temperature, dissolved oxygen (DO), and chromophoric dissolved organic matter (CDOM) were collected at three sites in Lake Qiandaohu, a large, deep subtropical reservoir in China. Additionally, we assessed the changes in DO stratification over the past 61 years (1953-2013) based on our empirical models and long-term air temperature and transparency data. The DO concentration never fell below 2 mg/L, the critical value for anoxia, and the DO depth profiles were closely linked to the water temperature depth profiles. In the stable stratification period in summer and autumn, the significant increase in CDOM in the metalimnion explained the decrease in DO due to the oxygen consumed by CDOM. Well-developed oxygen stratification was detected at the three sites in spring, summer and autumn and was associated with thermal stratification. Oxycline depth was significantly negatively correlated with daily air temperature and thermocline thickness but significantly positively correlated with thermocline depth during the stratification weakness period (July-February). However, there were no significant correlations among these parameters during the stratification formation period (March-June). The increase of 1.67 °C in yearly average daily air temperature between 1980 and 2013 and the decrease of 0.78 m in Secchi disk depth caused a decrease of 1.65 m and 2.78 m in oxycline depth, respectively, facilitating oxygen stratification and decreasing water quality. Therefore, climate warming has had a substantial effect on water quality through changing the DO regime in Lake Qiandaohu. Copyright © 2015 Elsevier Ltd. All rights reserved.

The integration of two health systems: social stratification, work and health in East and West Germany.

PubMed

Lüschen, G; Niemann, S; Apelt, P

1997-03-01

This is an analysis of system integration, social stratification and work for health status and health care in East and West Germany. It is based on aggregate data and representative survey data of random samples of 2554 adults in both subsystems. Findings show that there were marked differences in life-expectancy prior to unification. The integration of the two systems, which occurred almost totally with regard to terms of West German health care organization, shows adjustment problems in the East for the public Health-Care-Funds and few if any for ambulatory care. The work situation has an impact on health, but there are no significant differences for East versus West. Social stratification variables show an influence on subjective health status for education (East) and for income, social status (West), while physician utilization (despite a preference of specialists by those with higher status) is not significantly determined by stratification variables in either East or West Germany. Beyond the central focus on work and stratification determinants a major finding pertains to a comparatively worse health situation for the aged and for women in what was the former East Germany. System models of Capitalism versus Socialism fit the results and recent history of the two systems to only a limited degree, as the West German corporate health system shows clear limits in following free market principles. The East German system, regardless of its centralized organization and move towards a socialist system, never fully abandoned the traditional model of German health care. Unlike the East German health system, that of West Germany, with its general expansion to 92% of the population, shows an increasing effect for social redistribution. The latter may be a reason why standard indicators of social stratification show less of an impact on health and health care than expected, while conditions at work clearly determine the health of people-the latter being the case in both

Effects of viscosity and conductivity stratification on the linear stability and transient growth within compressible Couette flow

NASA Astrophysics Data System (ADS)

Saikia, Bijaylakshmi; Ramachandran, Ashwin; Sinha, Krishnendu; Govindarajan, Rama

2017-02-01

Accurate prediction of laminar to turbulent transition in compressible flows is a challenging task, as it can be affected by a combination of factors. Compressibility causes large variations in thermodynamic as well as transport properties of a gas, which in turn are known to affect flow stability. We study the stratification of individual transport properties and their combined behavior. We also examine the effect of a change in the magnitude of viscosity and conductivity on flow stability. The Couette flow of a perfect gas is our model problem and both modal and non-modal analyses are carried out. We notice a large destabilizing role of the increase in the conductivity value and a dramatic stabilizing effect of mean viscosity stratification, over a range of free-stream Mach number, Reynolds number, Prandtl number, and disturbance wavenumber. In the combined case, viscosity stratification plays a dominant role. We find this to be the case for finite-time transient growth in the parameter regime below linear instability as well as asymptotically at large time. A budget of the transient growth energy amplification is also shown to identify the effects of transport properties on the constituents of perturbation energy. The extensive results presented in this paper, we believe should motivate those studying more realistic flows to examine how these contrasting effects of stratification come together.

Elite formation under occupation: the internal stratification of palestinian elites in the West Bank and Gaza Strip.

PubMed

Mazawi, A E; Yogev, A

1999-09-01

This paper examines the internal stratification of Palestinian elites in the West Bank and Gaza Strip under Israeli occupation. Our general aim is to clarify the extent to which social and political subordination to outside rule influences the development of indigenous elites in stateless societies. In contrast to nation-state societies, such elites may be horizontally stratified into a wider range of institutional settings, and vertically stratified by anti-occupation activism alongside the attainment of occupational prestige. In addition, context-specific determinants of their stratification patterns, such as refugee status, regionality, and country in which educational credentials were acquired, should be considered. A secondary content analysis of interviews conducted by the Palestinian Panorama centre with 249 elite members reveals, that the vertical stratification of Palestinian elites along occupational attainment and anti-occupation activism constitutes two quite independent status dimensions. A multinomial logit regression shows that, horizontally, elite groups are embedded in four distinct types of institutional activity, further demonstrating the multi-faceted formation of Palestinian elites. Contextual resources, such as refugee versus non-refugee status, regionality, and the acquiring of Western credentials, have differential effects on the vertical and horizontal stratification of Palestinian elites. The implications of these findings for further research on elite formation in the post-Oslo Palestinian society and in other stateless societies are discussed in conclusion.

Concierge or Information Desk: Teaching Social Stratification through the Malling of America.

ERIC Educational Resources Information Center

Manning, Robert D.; Price, Derek V.; Rich, Henry J.

1997-01-01

Describes an undergraduate sociology project in which students conducted research at working class and upper-middle class shopping malls. The research focused on social stratification and its manifestation in architectural character, spatial relationships, advertising, and consumer behavior. Includes an appendix that reproduces the fieldwork…

Prodromal Parkinsonism and Neurodegenerative Risk Stratification in REM Sleep Behavior Disorder

PubMed Central

Lawton, Michael; Rolinski, Michal; Evetts, Samuel; Baig, Fahd; Ruffmann, Claudio; Gornall, Aimie; Klein, Johannes C; Lo, Christine; Dennis, Gary; Bandmann, Oliver; Quinnell, Timothy; Zaiwalla, Zenobia; Ben-Shlomo, Yoav; Hu, Michele TM

2017-01-01

Abstract Objectives Rapid eye movement (REM) sleep behavior disorder (RBD) is the most specific marker of prodromal alpha-synucleinopathies. We sought to delineate the baseline clinical characteristics of RBD and evaluate risk stratification models. Methods Clinical assessments were performed in 171 RBD, 296 control, and 119 untreated Parkinson’s (PD) participants. Putative risk measures were assessed as predictors of prodromal neurodegeneration, and Movement Disorders Society (MDS) criteria for prodromal PD were applied. Participants were screened for common leucine-rich repeat kinase 2 (LRRK2)/glucocerebrosidase gene (GBA) gene mutations. Results Compared to controls, participants with RBD had higher rates of solvent exposure, head injury, smoking, obesity, and antidepressant use. GBA mutations were more common in RBD, but no LRRK2 mutations were found. RBD participants performed significantly worse than controls on Unified Parkinson’s Disease Rating Scale (UPDRS)-III, timed “get-up-and-go”, Flamingo test, Sniffin Sticks, and cognitive tests and had worse measures of constipation, quality of life (QOL), and orthostatic hypotension. For all these measures except UPDRS-III, RBD and PD participants were equally impaired. Depression, anxiety, and apathy were worse in RBD compared to PD participants. Stratification of people with RBD according to antidepressant use, obesity, and age altered the odds ratio (OR) of hyposmia compared to controls from 3.4 to 45.5. 74% (95% confidence interval [CI] 66%, 80%) of RBD participants met the MDS criteria for probable prodromal Parkinson’s compared to 0.3% (95% CI 0.009%, 2%) of controls. Conclusions RBD are impaired across a range of clinical measures consistent with prodromal PD and suggestive of a more severe nonmotor subtype. Clinical risk stratification has the potential to select higher risk patients for neuroprotective interventions. PMID:28472425

Gender Stratification in Vocational Education and the Labour Force in Finland.

ERIC Educational Resources Information Center

Stenstrom, Marja-Leena

A study determined the extent of gender stratification in Finnish vocational education and labor force, especially in the transition from school to work. It used follow-up data that Statistics Finland gathered in 1990 concerning the labor force status of the 1985 school leavers and the level of their educational qualifications 5 years later to…

Evaluation d’une grille de supervision des laboratoires des leishmanioses cutanées au Maroc

PubMed Central

El Mansouri, Bouchra; Amarir, Fatima; Hajli, Yamina; Fellah, Hajiba; Sebti, Faiza; Delouane, Bouchra; Sadak, Abderrahim; Adlaoui, El Bachir; Rhajaoui, Mohammed

2017-01-01

Introduction Afin d’évaluer une grille de contrôle standardisée de laboratoire de diagnostic des leishmanioses, comme nouveau outil de supervision. Méthodes Un essai pilote a été pratiqué sur sept laboratoires provinciaux, appartenant à quatre provinces au Maroc, en suivant l’évolution de leurs performances tous les deux ans, entre l’année 2006 et 2014. Cette étude détaille la situation des laboratoires provinciaux avant et après la mise en œuvre de la grille de supervision. Au total vingt et une grille sont analysées. Résultats En 2006, les résultats ont montré clairement une insuffisance des performances des laboratoires: besoin en formation (41.6%), personnel pratiquant le prélèvement cutané (25%), pénurie en matériels et réactifs (65%), gestions documentaire et local non conformes (85%). Différentes actions correctives ont été menées par le Laboratoire National de Référence des Leishmanioses (LNRL) durant la période d’étude. En 2014, le LNRL a enregistré une nette amélioration des performances des laboratoires. Les besoins en matière de formation, qualité du prélèvement, dotation en matériels et réactifs ont été comblés et une coordination efficace s’est établie entre le LNRL et les laboratoires provinciaux. Conclusion Ceci montre l'efficacité de la grille comme outil de supervision de grande qualité, et comme pierre angulaire de tout progrès qui doit être obtenu dans les programmes de lutte contre les leishmanioses. PMID:29187922

Simulating 2,368 temperate lakes reveals weak coherence in stratification phenology

USGS Publications Warehouse

Read, Jordan S.; Winslow, Luke A.; Hansen, Gretchen J. A.; Van Den Hoek, Jamon; Hanson, Paul C.; Bruce, Louise C; Markfort, Corey D.

2014-01-01

Changes in water temperatures resulting from climate warming can alter the structure and function of aquatic ecosystems. Lake-specific physical characteristics may play a role in mediating individual lake responses to climate. Past mechanistic studies of lake-climate interactions have simulated generic lake classes at large spatial scales or performed detailed analyses of small numbers of real lakes. Understanding the diversity of lake responses to climate change across landscapes requires a hybrid approach that couples site-specific lake characteristics with broad-scale environmental drivers. This study provides a substantial advancement in lake ecosystem modeling by combining open-source tools with freely available continental-scale data to mechanistically model daily temperatures for 2,368 Wisconsin lakes over three decades (1979-2011). The model accurately predicted observed surface layer temperatures (RMSE: 1.74°C) and the presence/absence of stratification (81.1% agreement). Among-lake coherence was strong for surface temperatures and weak for the timing of stratification, suggesting individual lake characteristics mediate some - but not all - ecologically relevant lake responses to climate.

La prise en charge d’une clientèle

PubMed Central

Roy, Andréanne; Breton, Mylaine; Loslier, Julie

2016-01-01

Résumé Objectif Analyser les facteurs qui incitent les médecins de famille nouvellement autorisés à faire de la prise en charge d’une clientèle en première ligne. Type d’étude Devis mixte séquentiel : questionnaire en ligne auto-administré auprès de médecins de famille, suivi d’entrevues individuelles. Contexte La Montérégie, qui est la deuxième région la plus populeuse du Québec, et qui présente des zones rurales et urbaines. Participants Tous les médecins de famille détenant un poste en Montérégie et ayant moins de 10 années d’expérience ont été sollicités, soit 366 médecins. Parmi eux, 118 ont complété le questionnaire en ligne (taux de réponse de 32,2 %). Parmi les répondants, 10 médecins ayant des profils de prise en charge variés ont été sélectionnés pour les entrevues individuelles. Principaux paramètres à l’étude Le pourcentage de temps de travail consacré à la prise en charge, analysé en parallèle avec différents facteurs facilitants et barrières à la prise en charge aux niveaux contextuel, organisationnel, du médecin de famille et de la clientèle. Résultats Les principaux facteurs facilitant la prise en charge sont la relation médecin-patient, l’intérêt pour les activités cliniques liées à la prise en charge, les modèles de rôles positifs, la collaboration avec une infirmière et l’accès adéquat aux ressources, notamment en santé mentale. Les principales barrières sont l’ampleur des tâches administratives, l’intérêt pour une pratique polyvalente, l’expérience négative de la prise en charge lors de la formation, un sentiment n’inaptitude à l’égard de la prise en charge, la lourdeur de la clientèle et le manque de soutien en début de pratique. Conclusion Certaines pistes de solution pour inciter les nouveaux médecins de famille à prendre en charge une clientèle sont proposées. Des points d’amélioration au niveau de la formation médicale, du soutien

Economic Consequences of Horizontal Stratification in Postsecondary Education: Evidence from Urban China

ERIC Educational Resources Information Center

Hu, Anning; Vargas, Nicholas

2015-01-01

Drawing on nationwide representative data, we study the patterns of horizontal stratification of higher education in contemporary urban Chinese society, examining how college major, location, and ranking affect college graduates' occupational income and the likelihood of assuming a managerial position. The results suggest that (1) college major…

The Sexual Stratification Hypothesis: Is the Decision to Arrest Influenced by the Victim/Suspect Racial/Ethnic Dyad?

PubMed

O'Neal, Eryn Nicole; Beckman, Laura O; Spohn, Cassia

2016-05-24

The sexual stratification hypothesis suggests that criminal justice responses to sexual victimization will differ depending on the victim/suspect racial/ethnic dyad. Previous research examining the sexual stratification hypothesis has primarily focused on court processes, and the small body of literature examining arrest decisions is dated. There remains substantial opportunity for testing the sexual stratification hypothesis at response stages apart from the court level (i.e., arrest). Using quantitative data on 655 sexual assault complaints that were reported to the Los Angeles County Sherriff's Department (LASD) and the Los Angeles Police Department (LAPD) in 2008, this study examines the effect of the victim/suspect racial/ethnic dyad on the decision to arrest. Findings suggest that police consider the victim/suspect racial/ethnic dyad when making arrest decisions. In addition, victim characteristics, strength of evidence indicators, and measures of case factors predict the police decision to make an arrest. © The Author(s) 2016.

Paraplégie compliquant une plaie abdominale antérieure par arme blanche

PubMed Central

Elahmadi, Brahim; Awab, Almahdi; El Moussaoui, Rachid; El Hijri, Ahmed; Azzouzi, Abderrahim; Alilou, Mustapha

2015-01-01

Les traumatismes médullaires sont des complications rares des plaies abdominales antérieures par arme blanche. Son diagnostic est difficile parfois retardé. L'imagerie par résonance magnétique reste l'examen de choix. Le traitement dépend du tableau clinique et de la gravité de la souffrance médullaire. Le pronostic est corrélé à l’étendue et à la nature de la lésion médullaire. Nous rapportons un cas exceptionnel d'un traumatisme médullaire chez une patiente victime d'une plaie abdominale antérieure par arme blanche. PMID:25995808

Rumen content stratification in the giraffe (Giraffa camelopardalis).

PubMed

Sauer, Cathrine; Clauss, Marcus; Bertelsen, Mads F; Weisbjerg, Martin R; Lund, Peter

2017-01-01

Ruminants differ in the degree of rumen content stratification, with 'cattle-types' (i.e., the grazing and intermediate feeding ruminants) having stratified content, whereas 'moose-types' (i.e., the browsing ruminants) have unstratified content. The feeding ecology, as well as the digestive morphophysiology of the giraffe (Giraffa camelopardalis), suggest that it is a 'moose-type' ruminant. Correspondingly, the giraffe should have an unstratified rumen content and an even rumen papillation pattern. Digesta samples were collected from along the digestive tract of 27 wild-caught giraffes kept in bomas for up to 2months, and 10 giraffes kept in zoological gardens throughout their lives. Samples were analysed for concentration of dry matter, fibre fractions, volatile fatty acids and NH 3 , as well as mean particle size and pH. There was no difference between the dorsal and ventral rumen region in any of these parameters, indicating homogenous rumen content in the giraffes. In addition to the digesta samples, samples of dorsal rumen, ventral rumen and atrium ruminis mucosa were collected and the papillary surface enlargement factor was determined, as a proxy for content stratification. The even rumen papillation pattern observed also supported the concept of an unstratified rumen content in giraffes. Zoo giraffes had a slightly more uneven papillation pattern than boma giraffes. This finding could not be matched by differences in physical characteristics of the rumen content, probably due to an influence of fasting time ante mortem on these parameters. Copyright © 2016 Elsevier Inc. All rights reserved.

Utility of the exercise electrocardiogram testing in sudden cardiac death risk stratification.

PubMed

Refaat, Marwan M; Hotait, Mostafa; Tseng, Zian H

2014-07-01

Sudden cardiac death (SCD) remains a major public health problem. Current established criteria identifying those at risk of sudden arrhythmic death, and likely to benefit from implantable cardioverter defibrillators (ICDs), are neither sensitive nor specific. Exercise electrocardiogram (ECG) testing was traditionally used for information concerning patients' symptoms, exercise capacity, cardiovascular function, myocardial ischemia detection, and hemodynamic responses during activity in patients with hypertrophic cardiomyopathy. We conducted a systematic review of MEDLINE on the utility of exercise ECG testing in SCD risk stratification. Exercise testing can unmask suspected primary electrical diseases in certain patients (catecholaminergic polymorphic ventricular tachycardia or concealed long QT syndrome) and can be effectively utilized to risk stratify patients at an increased (such as early repolarization syndrome and Brugada syndrome) or decreased risk of SCD, such as the loss of preexcitation on exercise testing in asymptomatic Wolff-Parkinson-White syndrome. Exercise ECG testing helps in SCD risk stratification in patients with and without arrhythmogenic hereditary syndromes. © 2014 Wiley Periodicals, Inc.

Stratification calculations in a heated cryogenic oxygen storage tank at zero gravity

NASA Technical Reports Server (NTRS)

Shuttles, J. T.; Smith, G. L.

1971-01-01

A cylindrical one-dimensional model of the Apollo cyrogenic oxygen storage tank has been developed to study the effect of stratification in the tank. Zero gravity was assumed, and only the thermally induced motions were considered. The governing equations were derived from conservation laws and solved on a digital computer. Realistic thermodynamic and transport properties were used. Calculations were made for a wide range of conditions. The results show the fluid behavior to be dependent on the quantity in the tank or equivalently the bulk fluid temperature. For high quantities (low temperatures) the tank pressure rose rapidly with heat addition, the heater temperature remained low, and significant pressure drop potentials accrued. For low quantities the tank pressure rose more slowly with heat addition and the heater temperature became high. A high degree of stratification resulted for all conditions; however, the stratified region extended appreciably into the tank only for the lowest tank quantity.

Une cryptococcose disséminée compliquant un traitement par prednisone et azathioprime d'un pemphigus vulgaire

PubMed Central

Wafa, Ammouri; Hicham, Harmouche; Yassir, Afifi; Zoubida, Tazi Mezalek; Mohamed, Adnaoui; Mohamed, Aouni; Amine, Hassani; Abdelaziz, Maaouni

2011-01-01

L'infection à cryptocoque est une complication redoutable chez les patients traités par immunosuppresseurs et dont l’évolution peut être rapidement fatal en cas de retard diagnostic. Nous rapportons le cas d'une patiente âgée de 70 ans, ayant des antécédents de pemphigus vulgaire traité par prednisone et azathioprime et admise dans le service de médecine Interne pour des nodules sous cutanés atypiques. Le diagnostic retenu était celui d'une cryptococcose disséminée. L’évolution était rapidement fatale malgré le traitement antifongique. PMID:22187617

Choc hémorragique suite à une ponction biopsie rénale (PBR): à propos d'un cas

PubMed Central

El Hammoumi, Jalal; Boukatta, Brahim; Houari, Nawfal; Elbouazzaoui, Abderrahim; Sbai, Hicham; Kanjaa, Nabil

2015-01-01

La ponction biopsie rénale (PBR) est un examen indispensable en néphrologie mais à risque de complications graves surtout hémorragique. Nous rapportons l'observation d'un patient âgé de 27 ans ayant bénéficié d'une PBR pour un diagnostic étiologique d'une insuffisance rénale aigue, l’évolution après la biopsie a été marquée par l'installation d'un choc hémorragique d'où la prise en charge en réanimation avec une néphrectomie d'hémostase. PMID:26848362

Hémophilie B mineure révélée par une hémorragie cérébrale: à propos d'un cas

PubMed Central

Naji, Abdelhalim; Rkain, Maria; Amrani, Rim; Benajiba, Noufissa

2015-01-01

L'hémorragie intracrânienne (HIC) du nouveau-né à terme est une pathologie rare, leur prévalence est estimée à 2% des naissances vivantes. Les manifestations cliniques sont variables et non spécifique. Les causes d'HIC sont multiples et souvent intriquées, les mécanismes physiopathologiques principaux sont la dysrégulation du débit cérébral, une obstruction des vaisseaux ou une coagulation intravasculaire; ou une lésion directe par traumatisme. Nous rapportons le cas d'un nourrisson d'un mois qui a été admis dans notre service pour prendre en charge des convulsions associées à une pâleur cutanéomuqueuse, suite à laquelle l'examen biologique a mis fortuitement en faveur une hémophilie mineure sur une maladie hémorragique tardive. PMID:26491519

State of the Art: Blood Biomarkers for Risk Stratification in Patients with Stable Ischemic Heart Disease.

PubMed

Omland, Torbjørn; White, Harvey D

2017-01-01

Multiple circulating biomarkers have been associated with the incidence of cardiovascular events and proposed as potential tools for risk stratification in stable ischemic heart disease (IHD), yet current guidelines do not make any firm recommendations concerning the use of biomarkers for risk stratification in this setting. This state-of-the-art review provides an overview of biomarkers for risk stratification in stable IHD. Circulating biomarkers associated with the risk of cardiovascular events in patients with stable IHD reflect different pathophysiological processes, including myocardial injury, myocardial stress and remodeling, metabolic status, vascular inflammation, and oxidative stress. Compared to the primary prevention setting, biomarkers reflecting end-organ damage and future risk of heart failure development and cardiovascular death may play more important roles in the stable IHD setting. Accordingly, biomarkers that reflect chronic, low-grade myocardial injury, and stress, i.e., high-sensitivity cardiac troponins and natriuretic peptides, provide graded and incremental prognostic information to conventional risk markers. In contrast, in stable IHD patients the prognostic value of traditional metabolic biomarkers, including serum lipids, is limited. Among several novel biomarkers, growth-differentiation factor-15 may provide the most robust prognostic information, whereas most inflammatory markers provide limited incremental prognostic information to risk factor models that include conventional risk factors, natriuretic peptides, and high-sensitivity troponins. Circulating biomarkers hold promise as useful tools for risk stratification in stable IHD, but their future incorporation into clinically useful risk scores will depend on prospective, rigorously performed clinical trials that document enhanced risk prediction. © 2016 American Association for Clinical Chemistry.

The Auckland Cataract Study: Assessing Preoperative Risk Stratification Systems for Phacoemulsification Surgery in a Teaching Hospital.

PubMed

Kim, Bia Z; Patel, Dipika V; Sherwin, Trevor; McGhee, Charles N J

2016-11-01

To evaluate 2 preoperative risk stratification systems for assessing the risk of complications in phacoemulsification cataract surgery, performed by residents, fellows, and attending physicians in a public teaching hospital. Cohort study. One observer assessed the clinical data of 500 consecutive cases, prior to phacoemulsification cataract surgery performed between April and June 2015 at Greenlane Clinical Centre, Auckland, New Zealand. Preoperatively 2 risk scores were calculated for each case using the Muhtaseb and Buckinghamshire risk stratification systems. Complications, intraoperative and postoperative, and visual outcomes were analyzed in relation to these risk scores. Intraoperative complication rates increased with higher risk scores using the Muhtaseb or Buckinghamshire stratification system (P = .001 and P = .003, respectively, n = 500). The odds ratios for residents and fellows were not significantly different from attending physicians after case-mix adjustment according to risk scores (P > .05). Postoperative complication rates increased with higher Buckinghamshire risk scores but not with Muhtaseb scores (P = .014 and P = .094, respectively, n = 476). Postoperative corrected-distance visual acuity was poorer with higher risk scores (P < .001 for both, n = 476). This study confirms that the risk of intraoperative complications increases with higher preoperative risk scores. Furthermore, higher risk scores correlate with poorer postoperative visual acuity and the Buckinghamshire risk score also correlates with postoperative complications. Therefore, preoperative assessment using such risk stratification systems could assist individual informed consent, preoperative surgical planning, safe allocation of cases to trainees, and more meaningful analyses of outcomes for individual surgeons and institutions. Copyright © 2016 Elsevier Inc. All rights reserved.

Atherothrombotic Risk Stratification and Ezetimibe for Secondary Prevention.

PubMed

Bohula, Erin A; Morrow, David A; Giugliano, Robert P; Blazing, Michael A; He, Ping; Park, Jeong-Gun; Murphy, Sabina A; White, Jennifer A; Kesaniemi, Y Antero; Pedersen, Terje R; Brady, Adrian J; Mitchel, Yale; Cannon, Christopher P; Braunwald, Eugene

2017-02-28

Ezetimibe improves cardiovascular (CV) outcomes in patients stabilized after acute coronary syndrome (ACS) when added to statin therapy. After ACS, patients vary considerably in their risk for recurrent CV events. This study tested the hypothesis that atherothrombotic risk stratification may be useful to identify post-ACS patients who have the greatest potential for benefit from the addition of ezetimibe to statin therapy. The TIMI (Thrombolysis In Myocardial Infarction) Risk Score for Secondary Prevention (TRS 2°P) is a simple 9-point risk stratification tool, previously developed in a large population with atherothrombosis to predict CV death, myocardial infarction (MI), and ischemic stroke (CV death/MI/ischemic cerebrovascular accident [iCVA]). The current study applied this tool prospectively to 17,717 post-ACS patients randomized either to ezetimibe and simvastatin or to placebo and simvastatin in IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial). Treatment efficacy was assessed by baseline risk for CV death/MI/iCVA, the IMPROVE-IT composite endpoints (CE), and individual component endpoints at 7 years. All 9 clinical variables in the TRS 2°P were independent risk indicators for CV death/MI/iCVA (p < 0.001). The integer-based scheme showed a strong graded relationship with the rate of CV death/MI/iCVA, the trial CE, and the individual components (p trend <0.0001 for each). High-risk patients (n = 4,393; 25%), defined by ≥3 risk indicators, had a 6.3% (95% confidence interval: 2.9% to 9.7%) absolute risk reduction in CV death/MI/iCVA at 7 years with ezetimibe/simvastatin, thus translating to a number-needed-to-treat of 16. Intermediate-risk patients (2 risk indicators; n = 5,292; 30%) had a 2.2% (95% confidence interval: -0.3% to 4.6%) absolute risk reduction. Low-risk patients (0 to 1 risk indicators; n = 8,032; 45%) did not appear to derive benefit from the addition of ezetimibe (p interaction = 0.010). Similar

Population Stratification in the Candidate Gene Study: Fatal Threat or Red Herring?

ERIC Educational Resources Information Center

Hutchison, Kent E.; Stallings, Michael; McGeary, John; Bryan, Angela

2004-01-01

Advances in molecular genetics have provided behavioral scientists with a means of investigating the influence of genetic factors on human behavior. Unfortunately, recent candidate gene studies have produced inconsistent results, and a frequent scapegoat for the lack of replication across studies is the threat of population stratification. This…

Simulating rotating fluid bodies: When is vorticity generation via density-stratification important?

NASA Astrophysics Data System (ADS)

Evonuk, M.; Samuel, H.

2012-04-01

Differential rotation is one of the key components needed to maintain a magnetic dynamo, therefore it is important to understand the processes that generate differential rotation in rotating bodies. In a rotating density-stratified fluid, local vorticity generation occurs as fluid parcels move radially, expanding or contracting with respect to the background density stratification. The convergence of this vorticity forms zonal flow structures as a function of the radius and the slope of the background density profile. While this effect is thought to be of importance in bodies that are quickly rotating and highly turbulent with large density stratifications such as Jupiter, it is generally neglected in bodies such as the Earth's outer core, where the density change is small. Simulations of thermal convection in the 2D rotating equatorial plane are conducted to determine the parameter regime where local vorticity generation plays a significant role in organizing the fluid flow. Three regimes are found: a dipolar flow regime, where the flow is not organized by the rotation, a transitional flow regime, and a differential flow regime, where the flow is strongly organized into differential rotation with multiple jets. A scaling law is determined based on the convective Rossby number and the density contrast across the equatorial plane, providing a simple way to determine in which regime a given body lies. While a giant planet such as Jupiter lies firmly in the differential flow regime as expected, the Earth's outer core is also found to lie in the differential flow regime indicating that, even in the Earth's outer core, where the density contrast is small, vorticity contributions via fluid movement through the density stratification may be non-negligible.

Simulating rotating fluid bodies: When is vorticity generation via density-stratification important?

NASA Astrophysics Data System (ADS)

Evonuk, M.; Samuel, H.

2012-12-01

Differential rotation is one of the key components needed to maintain a magnetic dynamo, therefore it is important to understand the processes that generate differential rotation in rotating bodies. In a rotating density-stratified fluid, local vorticity generation occurs as fluid parcels move radially, expanding or contracting with respect to the background density stratification. The convergence of this vorticity forms zonal flow structures as a function of the radius and the slope of the background density profile. While this effect is thought to be of importance in bodies that are quickly rotating and highly turbulent with large density stratifications such as Jupiter, it is generally neglected in bodies such as the Earth's outer core, where the density change is small. Simulations of thermal convection in the 2D rotating equatorial plane are conducted to determine the parameter regime where local vorticity generation plays a significant role in organizing the fluid flow. Three regimes are found: a dipolar flow regime, where the flow is not organized by the rotation, a transitional flow regime, and a differential flow regime, where the flow is strongly organized into differential rotation with multiple jets. A scaling law is determined based on the convective Rossby number and the density contrast across the equatorial plane, providing a simple way to determine in which regime a given body lies. While a giant planet such as Jupiter lies firmly in the differential flow regime as expected, the Earth's outer core is also found to lie in the differential flow regime indicating that, even in the Earth's outer core, where the density contrast is small, vorticity contributions via fluid movement through the density stratification may be non-negligible.

Gender and cultural differences in the association between family roles, social stratification, and alcohol use: a European cross-cultural analysis.

PubMed

Kuntsche, Sandra; Gmel, Gerhard; Knibbe, Ronald A; Kuendig, Hervé; Bloomfield, Kim; Kramer, Stephanie; Grittner, Ulrike

2006-01-01

First, this paper investigates (i) gender differences in associations of social stratification, family roles, and heavy drinking, and (ii) country differences in these associations. Second, it seeks to explain country differences in the associations of social stratification and family roles with alcohol consumption by societal level variables. Survey data of 25 to 49-years-old from eight European countries were used. Logistic regressions were used to analyse gender differences in the association between family roles (marriage, having children), social stratification (education, employment), and heavy drinking (>20 g/day for women; 30 g/day for men). Gender differences were tested by means of interactions between gender and social stratification/family roles. Structural measures of work desirability, social welfare, and gender equity were used to explain differences in associations across countries. The associations between social stratification, family roles, and heavy drinking varied across gender and countries. A country's social welfare system was associated with heavy drinking only among women. Women in countries with a strong social welfare system, such as Nordic countries, tended to drink more heavily if employed, having lower formal education, and a non-traditional family role. In countries with weak social welfare systems or work desirability, heavy drinking was associated with high education, while effects of family roles and employment were small. It appeared that the social welfare system and gender equity of a country determines to a large extent how education, employment, and family roles are associated with heavy drinking.

Possibilité d'une nouvelle technologie de traitement des minerais de fer de l'Ouenza par radiométrie

NASA Astrophysics Data System (ADS)

Idres, A.; Bounouala, M.

2005-05-01

En l'absence d'une technologie fiable de traitement des haldes de minerais de fer, les caractéristiques minéralogiques et chimiques complexes et les effets néfastes des résidus miniers posent réellement un problème environnemental. A cet effet, une étude minéralogique et chimique du minerai de fer a été menée en utilisant des techniques multiples (microscopie optique, DRX, FX, MEB). En tenant compte de la nature des résidus, des échantillons représentatifs ont été testés par séparation radiométrique. Plusieurs paramètres ont été caractérisés tels que la vitesse de la bande transporteuse, le temps d'émission des rayons gamma et la granulométrie d'alimentation du procédé. Les résultats ainsi obtenus par cette méthode de séparation sont très significatifs en récupération et en teneur fer. Cependant, cette nouvelle technologie permet d'une part une meilleure valorisation des minerais de fer et d'autre part une réduction du tonnage stocké sur le carreau de la mine.

Une alternative au cobalt pour la synthese de nanotubes de carbone monoparoi par plasma inductif thermique

NASA Astrophysics Data System (ADS)

Carrier, Jean-Francois

Les nanotubes de carbone de type monoparoi (C-SWNT) sont une classe recente de nanomateriaux qui ont fait leur apparition en 1991. L'interet qu'on leur accorde provient des nombreuses proprietes d'avant-plan qu'ils possedent. Leur resistance mecanique serait des plus rigide, tout comme ils peuvent conduire l'electricite et la chaleur d'une maniere inegalee. Non moins, les C-SWNT promettent de devenir une nouvelle classe de plateforme moleculaire, en servant de site d'attache pour des groupements reactifs. Les promesses de ce type particulier de nanomateriau sont nombreuses, la question aujourd'hui est de comment les realiser. La technologie de synthese par plasma inductif thermique se situe avantageusement pour la qualite de ses produits, sa productivite et les faibles couts d'operation. Par contre, des recherches recentes ont permis de mettre en lumiere des risques d'expositions reliees a l'utilisation du cobalt, comme catalyseur de synthese; son elimination ou bien son remplacement est devenu une preoccupation importante. Quatre recettes alternatives ont ete mises a l'essai afin de trouver une alternative plus securitaire a la recette de base; un melange catalytique ternaire, compose de nickel, de cobalt et d'oxyde d'yttrium. La premiere consiste essentiellement a remplacer la proportion massique de cobalt par du nickel, qui etait deja present dans la recette de base. Les trois options suivantes contiennent de nouveaux catalyseurs, en remplacement au Co, qui sont apparus dans plusieurs recherches scientifiques au courant des dernieres annees: le dioxyde de zircone (ZrO2), dioxyde de manganese (MnO2) et le molybdene (Mo). La methode utilisee consiste a vaporiser la matiere premiere, sous forme solide, dans un reacteur plasma a haute frequence (3 MHz) a paroi refroidi. Apres le passage dans le plasma, le systeme traverse une section dite de "croissance", isolee thermiquement a l'aide de graphite, afin de maintenir une certaine plage de temperature favorable a la

The Dynamics of Social Stratification in Contemporary Asian Societies. Asian Studies Module.

ERIC Educational Resources Information Center

Inyang, Ambrose

This curriculum module is designed to provide potential users with access to pedagogic techniques and scholarly works on the subject of social stratification in contemporary Asian societies that can be effectively integrated into appropriate sociology and other relevant courses. First, a set of goals and learning objectives is presented in an…

Sycamore Seed Germination: The Effects of Provenance, Stratification, Temperature, and Parent Tree

Treesearch

Charles D. Webb; Robert E. Farmer

1968-01-01

Various stratification periods and germination temperatures were applied to sycamore seed collected along the Chattahoochee River from north Georgia to west Florida. Results showed that percent and speed of germination were greater for seed from southern than from northern provenances. Percent and speed of germination increased as temperature increased. The...

Stratification requirements for germination of western larch (Larix occidentalis Nutt.) seed.

Treesearch

Frank C. Sorenson

1990-01-01

A northeast Washington collection of western larch seeds was stratified for 0,10, 20, 40, and 80 days and incubated at 55, 64, and 73 °F. The germination percentage of filled seeds and speed and uniformity of germination were improved by long stratification, particularly at the lowest incubation temperature. Stratified seeds were also nursery sown in early April and...

Fistule vésico-vaginale néoplasique secondaire à une tumeur de vessie: une entité rare

PubMed Central

Bagayogo, Tidiani; Jakhal, Nabil; Slaoui, Amine; Ziouziou, Imad; Karmouni, Tariq; El Khader, Khalid; Koutani, Abdelatif; Andaloussi, AhmedI bn Attya

2016-01-01

La fistule vésico-vaginale sur tumeur de vessie est extrêmement rare. Nous rapportons un cas de fistule vésico-vaginale (FVV) néoplasique chez une patiente de 54 ans, ménopausée, sans antécédent chirurgical ou de traumatisme obstétrical récent. La biopsie des berges de la fistule est revenue en faveur d’un carcinome urothélial. A la lumière de cette observation, nous discutons les formes étiologiques ainsi que les différentes stratégies thérapeutiques respectives des FVV. PMID:28250883

Evaluation of stratification factors and score-scales in clinical trials of treatment of clinical mastitis in dairy cows.

PubMed

Hektoen, L; Ødegaard, S A; Løken, T; Larsen, S

2004-05-01

There is often a need to reduce sample size in clinical trials due to practical limitations and ethical considerations. Better comparability between treatment groups by use of stratification in the design, and use of continuous outcome variables in the evaluation of treatment results, are two methods that can be used in order to achieve this. In this paper the choice of stratification factors in trials of clinical mastitis in dairy cows is investigated, and two score-scales for evaluation of clinical mastitis are introduced. The outcome in 57 dairy cows suffering from clinical mastitis and included in a clinical trial comparing homeopathic treatment, placebo and a standard antibiotic treatment is investigated. The strata of various stratification factors are compared across treatments to determine which other factors influence outcome. The two score scales, measuring acute and chronic mastitis symptoms, respectively, are evaluated on their ability to differentiate between patients classified from clinical criteria as responders or non-responders to treatment. Differences were found between the strata of the factors severity of mastitis, lactation number, previous mastitis this lactation and bacteriological findings. These factors influence outcome of treatment and appear relevant as stratification factors in mastitis trials. Both score scales differentiated between responders and non-responders to treatment and were found useful for evaluation of mastitis and mastitis treatment.

Inertial stratification of an expanding highly ionized multicomponent plasma bunch

NASA Astrophysics Data System (ADS)

Kozhenkova, O. A.; Motorin, A. A.; Stupitskii, E. L.

2013-09-01

The initial composition of a four-component plasma bunch of a high specific energy has been determined, as well as its characteristics during the process of expansion. It is shown that the interaction of particles under a high energy is of the Coulomb character and this interaction is unable to ensure the same velocity of components with different atomic masses right from the very beginning of bunch expansion, leading to their radical stratification.

Principal Stratification: A Tool for Understanding Variation in Program Effects across Endogenous Subgroups

ERIC Educational Resources Information Center

Page, Lindsay C.; Feller, Avi; Grindal, Todd; Miratrix, Luke; Somers, Marie-Andree

2015-01-01

Increasingly, researchers are interested in questions regarding treatment-effect variation across partially or fully latent subgroups defined not by pretreatment characteristics but by postrandomization actions. One promising approach to address such questions is principal stratification. Under this framework, a researcher defines endogenous…

Effects of density stratification on the frequencies of the inertial-gravity modes of the Earth's fluid core

NASA Astrophysics Data System (ADS)

Seyed-Mahmoud, B.; Moradi, A.; Kamruzzaman, M.; Naseri, H.

2015-08-01

The Earth's outer core is a rotating ellipsoidal shell of compressible, stratified and self-gravitating fluid. As such, in the treatment of geophysical problems a realistic model of this body needs to be considered. In this work, we consider compressible and stratified fluid core models with different stratification parameters, related to the local Brunt-Väisälä frequency, in order to study the effects of the core's density stratification on the frequencies of some of the inertial-gravity modes of this body. The inertial-gravity modes of the core are free oscillations with periods longer than 12 hr. Historically, an incompressible and homogeneous fluid is considered to study these modes and analytical solutions are known for the frequencies and the displacement eigenfunctions of a spherical model. We show that for a compressible and stratified spherical core model the effects of non-neutral density stratification may be significant, and the frequencies of these modes may change from model to model. For example, for a spherical core model the frequency of the spin-over mode, the (2, 1, 1) mode, is unaffected while that of the (4, 1, 1) mode is changed from -0.410 for the Poincaré core model to -0.434, -0.447 and -0.483 for core models with the stability parameter β = -0.001, -0.002 and -0.005, respectively, a maximum change of about 18 per cent when β = -0.005. Our results also show that for small stratification parameter, |β| ≤ 0.005, the frequency of an inertial-gravity mode is a nearly linear function of β but the slope of the line is different for different modes, and that the effects of density stratification on the frequency of a mode is likely related to its spatial structure, which remains the same in different Earth models. We also compute the frequencies of some of the modes of the `PREM' (spherical shell) core model and show that the frequencies of these modes may also be significantly affected by non-zero β.

Radionécrose cérébrale chez des patients irradiés pour cancers du nasopharynx: à propos de 3 cas

PubMed Central

El Mazghi, Abderrahman; Lalya, Issam; Loukili, Kaoutar; El Kacemi, Hanan; Kebdani, Taieb; Hassouni, Khalid

2014-01-01

La radionécrose cérébrale est une complication tardive, iatrogène, relativement rare de la radiothérapie qui survient après plus de six mois suivant le début du traitement. Elle pourrait s'expliquer par la conjonction de lésions vasculaires, gliales et d'ordre immunologiques. Elle peut mettre en jeu le pronostic fonctionnel et vital du malade. La prévention de cette affection redoutable est fondamentale vu l'absence de traitement potentiellement efficace. Nous rapportons 03 nouveaux cas, chez des patients traités par chimiothérapie d'induction puis radio- chimiothérapie concomitante pour des cancers localement avancés du nasopharynx. Le diagnostic a été orienté par l'IRM spectroscopique et l’évolution était favorable sous corticothérapie dans les 03 cas. PMID:25722784

A Risk Stratification Model for Lung Cancer Based on Gene Coexpression Network and Deep Learning

PubMed Central

2018-01-01

Risk stratification model for lung cancer with gene expression profile is of great interest. Instead of previous models based on individual prognostic genes, we aimed to develop a novel system-level risk stratification model for lung adenocarcinoma based on gene coexpression network. Using multiple microarray, gene coexpression network analysis was performed to identify survival-related networks. A deep learning based risk stratification model was constructed with representative genes of these networks. The model was validated in two test sets. Survival analysis was performed using the output of the model to evaluate whether it could predict patients' survival independent of clinicopathological variables. Five networks were significantly associated with patients' survival. Considering prognostic significance and representativeness, genes of the two survival-related networks were selected for input of the model. The output of the model was significantly associated with patients' survival in two test sets and training set (p < 0.00001, p < 0.0001 and p = 0.02 for training and test sets 1 and 2, resp.). In multivariate analyses, the model was associated with patients' prognosis independent of other clinicopathological features. Our study presents a new perspective on incorporating gene coexpression networks into the gene expression signature and clinical application of deep learning in genomic data science for prognosis prediction. PMID:29581968

Etiologies des hypertensions artérielles endocrines: à propos d'une série de cas

PubMed Central

Bouznad, Naima; El Mghari, Ghizlane; El Ansari, Nawal

2016-01-01

Les hypertensions artérielles (HTA) d'origine endocrine restent une cause rare d'HTA, sa prévalence globale n'excède pas 4% des hypertendus. L'intérêt de la recherche des HTA endocrines réside dans la gravité de certaines formes parfois mortelles et le caractère potentiellement curable et réversible de ces HTA. Le but du travail est de déterminer le profil clinique, para clinique, étiologique et thérapeutique des HTA secondaires d'origine endocrine chez les patients suivis au service d'endocrinologie au CHU Mohamed IV à Marrakech. Il s'agit d'une étude descriptive prospective s’étalant sur une période de 4 ans incluant 45 patients ayant une HTA endocrinienne. La moyenne d’âge est de 44,89 ans, avec une nette prédominance du sexe féminine (sexe ratio de 0,49). Les étiologies des HTA endocrines étaient dominées par le phéochromocytome (17 cas), l'hypercorticisme (11 cas) et l'acromégalie (8 cas). L'HTA était paroxystique dans 24,4%. Elle était d'emblée sevère classée grade 3 dans 40% des cas. L'HTA a été compliquée de cardiopathie dans 24% des cas et de néphropathie dans 20% des cas. Le traitement curatif a permis une guérison de l'HTA chez 60% (27 cas). Le diagnostic des HTA secondaires endocrines est parfois difficile du fait de l'absence de spécificité clinique. Il n'est pas exceptionnel que l'HTA soit l'unique manifestation de la maladie. Dans notre travail nous notons le caractère paroxystique et sévère de l'HTA. Le caractère éventuellement curable des HTA endocrines, dans plus des deux tiers des cas, fait qu'il est important de la dépister devant toute HTA sévère, résistante au traitement, ou en présence de signes cliniques, biologiques ou radiologiques évocateurs. PMID:27303586

Civic stratification and the exclusion of undocumented immigrants from cross-border health care*

PubMed Central

Torres, Jacqueline M.; Waldinger, Roger

2016-01-01

This paper proposes a theoretical framework and an empirical example of the relationship between the civic stratification of immigrants in the United States, and their access to healthcare. We use the 2007 Pew/RWJF Hispanic Healthcare Survey, a nationally representative survey of U.S. Latinos (n=2783 foreign-born respondents) and find that immigrants who are not citizens or legal permanent residents are significantly more likely to be excluded from care in both the U.S. and across borders. Legal status differences in cross-border care utilization persisted after controlling for health status, insurance coverage, and other potential demographic and socio-economic predictors of care. Exclusion from care on both sides of the border was associated with reduced rates of receiving timely preventive services. Civic stratification, and political determinants broadly speaking, should be considered alongside social determinants of population health and healthcare. PMID:26582512

Cytoplasmic expression of C-MYC protein is associated with risk stratification of mantle cell lymphoma.

PubMed

Gong, Yi; Zhang, Xi; Chen, Rui; Wei, Yan; Zou, Zhongmin; Chen, Xinghua

2017-01-01

To investigate the association of C-MYC protein expression and risk stratification in mantle cell lymphoma (MCL), and to evaluate the utility of C-MYC protein as a prognostic biomarker in clinical practice. We conducted immunohistochemical staining of C-MYC, Programmed cell death ligand 1 (PD-L1), CD8, Ki-67, p53 and SRY (sex determining region Y) -11 (SOX11) to investigate their expression in 64 patients with MCL. The staining results and other clinical data were evaluated for their roles in risk stratification of MCL cases using ANOVA, Chi-square, and Spearman's Rank correlation coefficient analysis. Immunohistochemical staining in our study indicated that SOX11, Ki-67 and p53 presented nuclear positivity of tumor cells, CD8 showed membrane positivity in infiltrating T lymphocytes while PD-L1 showed membrane and cytoplasmic positivity mainly in macrophage cells and little in tumor cells. We observed positive staining of C-MYC either in the nucleus or cytoplasm or in both subcellular locations. There were significant differences in cytoplasmic C-MYC expression, Ki-67 proliferative index of tumor cells, and CD8 positive tumor infiltrating lymphocytes (CD8+TIL) among three risk groups ( P  = 0.000, P  = 0.037 and P =0.020, respectively). However, no significant differences existed in the expression of nuclear C-MYC, SOX11, p53, and PD-L1 in MCL patients with low-, intermediate-, and high risks. In addition, patient age and serum LDH level were also significantly different among 3 groups of patients ( P  = 0.006 and P  = 0.000, respectively). Spearman's rank correlation coefficient analysis indicated that cytoplasmic C-MYC expression, Ki-67 index, age, WBC, as well as LDH level had significantly positive correlations with risk stratification ( P  = 0.000, 0.015, 0.000, 0.029 and 0.000, respectively), while CD8+TIL in tumor microenvironment negatively correlated with risk stratification of patients ( P  = 0.006). Patients with increased positive

Deglacial development of (sub) sea surface temperature and salinity in the subarctic northwest Pacific: Implications for upper-ocean stratification

NASA Astrophysics Data System (ADS)

Riethdorf, Jan-Rainer; Max, Lars; Nürnberg, Dirk; Lembke-Jene, Lester; Tiedemann, Ralf

2013-01-01

Based on models and proxy data, it has been proposed that salinity-driven stratification weakened in the subarctic North Pacific during the last deglaciation, which potentially contributed to the deglacial rise in atmospheric carbon dioxide. We present high-resolution subsurface temperature (TMg/Ca) and subsurface salinity-approximating (δ18Oivc-sw) records across the last 20,000 years from the subarctic North Pacific and its marginal seas, derived from combined stable oxygen isotopes and Mg/Ca ratios of the planktonic foraminiferal species Neogloboquadrina pachyderma (sin.). Our results indicate regionally differing changes of subsurface conditions. During the Heinrich Stadial 1 and the Younger Dryas cold phases, our sites were subject to reduced thermal stratification, brine rejection due to sea-ice formation, and increased advection of low-salinity water from the Alaskan Stream. In contrast, the Bølling-Allerød warm phase was characterized by strengthened thermal stratification, stronger sea-ice melting, and influence of surface waters that were less diluted by the Alaskan Stream. From direct comparison with alkenone-based sea surface temperature estimates (SSTUk'37), we suggest deglacial thermocline changes that were closely related to changes in seasonal contrasts and stratification of the mixed layer. The modern upper-ocean conditions seem to have developed only since the early Holocene.

Playing the (Sexual) Field: The Interactional Basis of Systems of Sexual Stratification

ERIC Educational Resources Information Center

Green, Adam Isaiah

2011-01-01

Recently, scholars have used a Bourdieusian theory of practice to analyze systems of sexual stratification, including an examination of sexual fields and sexual (or erotic) capital. While the broad structural features of the sexual field have been a point of focus in this latter research, a systematic analysis of the interactional processes that…

Stratification and the Emergence of the Postsecondary Private Education Sector in Vietnam

ERIC Educational Resources Information Center

Goyette, Kimberly Ann

2012-01-01

Vietnam has a strong public postsecondary education sector that has only recently begun to experience growth in nonpublic institutions. I investigate how the growth of nonpublic institutions may be related to stratification in Vietnam. I find that these institutions are more likely to serve more advantaged students from South Vietnam. Students pay…

A novel metric that quantifies risk stratification for evaluating diagnostic tests: The example of evaluating cervical-cancer screening tests across populations.

PubMed

Katki, Hormuzd A; Schiffman, Mark

2018-05-01

Our work involves assessing whether new biomarkers might be useful for cervical-cancer screening across populations with different disease prevalences and biomarker distributions. When comparing across populations, we show that standard diagnostic accuracy statistics (predictive values, risk-differences, Youden's index and Area Under the Curve (AUC)) can easily be misinterpreted. We introduce an intuitively simple statistic for a 2 × 2 table, Mean Risk Stratification (MRS): the average change in risk (pre-test vs. post-test) revealed for tested individuals. High MRS implies better risk separation achieved by testing. MRS has 3 key advantages for comparing test performance across populations with different disease prevalences and biomarker distributions. First, MRS demonstrates that conventional predictive values and the risk-difference do not measure risk-stratification because they do not account for test-positivity rates. Second, Youden's index and AUC measure only multiplicative relative gains in risk-stratification: AUC = 0.6 achieves only 20% of maximum risk-stratification (AUC = 0.9 achieves 80%). Third, large relative gains in risk-stratification might not imply large absolute gains if disease is rare, demonstrating a "high-bar" to justify population-based screening for rare diseases such as cancer. We illustrate MRS by our experience comparing the performance of cervical-cancer screening tests in China vs. the USA. The test with the worst AUC = 0.72 in China (visual inspection with acetic acid) provides twice the risk-stratification (i.e. MRS) of the test with best AUC = 0.83 in the USA (human papillomavirus and Pap cotesting) because China has three times more cervical precancer/cancer. MRS could be routinely calculated to better understand the clinical/public-health implications of standard diagnostic accuracy statistics. Published by Elsevier Inc.

Validation de la traduction française de la SURPS pour une population d’adolescents québécois

PubMed Central

Castonguay-Jolin, Laura; Perrier-Ménard, Eveline; Castellanos-Ryan, Natalie; Parent, Sophie; Vitaro, Frank; Tremblay, Richard E; Garel, Patricia; Séguin, Jean R; Conrod, Patricia J

2013-01-01

Objectif La Substance Use Risk Profile Scale (SURPS) est un instrument de dépistage des caractéristiques de personnalité qui représentent un risque pour le développement d’une consommation problématique de substances. La SURPS comporte 23 items évaluant 4 dimensions et permet aux intervenants en santé mentale de mieux cibler la prévention. La SURPS a été validée au Canada anglais, au Royaume-Uni, en Chine et au Sri Lanka; l’objectif de cette étude est de valider une traduction française de la SURPS pour des adolescents francophones québécois, en plus d’en tester la sensibilité dans une population clinique. Méthode Deux cent deux jeunes de 15 ans d’un échantillon communautaire ont répondu à la SURPS et à des mesures de la personnalité et de l’utilisation de substances. La cohérence interne, la solution factorielle et la validité concomitante de l’échelle ont été évaluées. Quarante adolescents (âge moyen de 15,7 ans) présentant un diagnostic psychiatrique ont également répondu à la SURPS et les scores ont été comparés aux normes de l’échantillon communautaire. Résultats La traduction française de la SURPS démontre une bonne cohérence interne ainsi qu’une solution factorielle à 4 facteurs semblable à la version originale. Ses 4 souséchelles ont une bonne validité concomitante. De plus, 3 de ses souséchelles sont corrélées avec des mesures relatives à la consommation de substances psychoactives. Finalement, 95 % des participants de l’échantillon clinique ont été identifiés à risque selon les scores limites de la SURPS. Conclusion La version française de la SURPS paraît être une mesure valide et sensible pouvant être utilisée auprès d’une population adolescente, québécoise et francophone. PMID:24099502

Using Multiple-hierarchy Stratification and Life Course Approaches to Understand Health Inequalities: The Intersecting Consequences of Race, Gender, SES, and Age.

PubMed

Brown, Tyson H; Richardson, Liana J; Hargrove, Taylor W; Thomas, Courtney S

2016-06-01

This study examines how the intersecting consequences of race-ethnicity, gender, socioeconomics status (SES), and age influence health inequality. We draw on multiple-hierarchy stratification and life course perspectives to address two main research questions. First, does racial-ethnic stratification of health vary by gender and/or SES? More specifically, are the joint health consequences of racial-ethnic, gender, and socioeconomic stratification additive or multiplicative? Second, does this combined inequality in health decrease, remain stable, or increase between middle and late life? We use panel data from the Health and Retirement Study (N = 12,976) to investigate between- and within-group differences in in self-rated health among whites, blacks, and Mexican Americans. Findings indicate that the effects of racial-ethnic, gender, and SES stratification are interactive, resulting in the greatest racial-ethnic inequalities in health among women and those with higher levels of SES. Furthermore, racial-ethnic/gender/SES inequalities in health tend to decline with age. These results are broadly consistent with intersectionality and aging-as-leveler hypotheses. © American Sociological Association 2016.

Using Multiple-hierarchy Stratification and Life Course Approaches to Understand Health Inequalities: The Intersecting Consequences of Race, Gender, SES, and Age

PubMed Central

Brown, Tyson H.; Richardson, Liana J.; Hargrove, Taylor W.; Thomas, Courtney S.

2016-01-01

This study examines how the intersecting consequences of race-ethnicity, gender, socioeconomics status (SES), and age influence health inequality. We draw on multiple-hierarchy stratification and life course perspectives to address two main research questions. First, does racial-ethnic stratification of health vary by gender and/or SES? More specifically, are the joint health consequences of racial-ethnic, gender, and socioeconomic stratification additive or multiplicative? Second, does this combined inequality in health decrease, remain stable, or increase between middle and late life? We use panel data from the Health and Retirement Study (N = 12,976) to investigate between- and within-group differences in in self-rated health among whites, blacks, and Mexican Americans. Findings indicate that the effects of racial-ethnic, gender, and SES stratification are interactive, resulting in the greatest racial-ethnic inequalities in health among women and those with higher levels of SES. Furthermore, racial-ethnic/gender/SES inequalities in health tend to decline with age. These results are broadly consistent with intersectionality and aging-as-leveler hypotheses. PMID:27284076

[Assessment of Heavy/ Light Chain Pairs of Immunoglobulin (Hevylite assay) -  Benefit for Stratification of Multiple Myeloma?].

PubMed

Ščudla, V; Lochaman, P; Pika, T; Zapletalová, J; Minařík, J; Bačovský, J

2015-01-01

The aim of the study was the comparison of two novel stratification models in multiple myeloma (MM), ie. according to Avet- Loiseau (A L) and according to Ludwig (L), based on the HLC r index (ratio of serum levels of involved- HLC/ uninvolved HLC, ie. HLC κ/ HLC  λ assessed using ie. nephelometric/turbidimetric technique using specific polyclonal antibodies on a Binding Site SPA(PLUS)) technique) and β(2) microglobulin (β(2) M) with selected prognostic factors (PF) of MM and staging systems according to Durie- Salmon (D S) and International Staging System (ISS). In a cohort of 132 patients (94 with IgG and 38 with IgA type of MM) at the time of dia-gnosis, we assessed HLC r, select-ed PF and D S, ISS, A L and L stratification systems. Unlike in IgA isotype, in IgG isotype we found a significant relationship of HLC r to stratification according to D S and ISS with the difference between A and B substages according to D S (p = 0.049) and between ISS stages 1 vs. 3 (p = 0.001). In the IgG group, there was highly significant relationship of the depth of Hb and albumin decrease and β(2) M increase to the results of stratification according to ISS, A L and L model (p < 0.0001), increase of LDH in the ISS system and A L, and creatinine according to ISS and L but not the relationship of the stages according to any of the stratification systems to the values of FLC r (ratio of serum free light chains κ/ λ of immunoglobulin), thrombocytes and Ca. In the IgA type, there was a significant relationship of the depth of the decrease of Hb, thrombocytes, albumin and increase of β(2) M to the results of stratification according to ISS, A L and L and increase of creatinine in the case of ISS, but not of the values of FLC r, Ca and LDH in the case of any of the stratification systems. The degree of correlation of selected PF, especially of Hb, albumin and β(2) M, event. of thrombocytes, LDH and creatinine to the stages

[Municipalities Stratification for Health Performance Evaluation].

PubMed

Calvo, Maria Cristina Marino; Lacerda, Josimari Telino de; Colussi, Claudia Flemming; Schneider, Ione Jayce Ceola; Rocha, Thiago Augusto Hernandes

2016-01-01

to propose and present a stratification of Brazilian municipalities into homogeneous groups for evaluation studies of health management performance. this was a methodological study, with selected indicators which classify municipalities according to conditions that influence the health management and population size; data for the year 2010 were collected from demographic and health databases; correlation tests and factor analysis were used. seven strata were identified - Large-sized; Medium-sized with favorable, regular or unfavorable influences; and Small-sized with favorable, regular or unfavorable influences -; there was a concentration of municipalities with favorable influences in strata with better purchasing power and funding, as well as a concentration of municipalities with unfavorable influences in the North and Northeast regions. the proposed classification grouped similar municipalities regarding influential factors in health management, which allowed the identification of comparable groups of municipalities, setting up a consistent alternative to performance evaluation studies.

Chemical stratification of cratonic lithosphere: constraints from the Northern Slave craton, Canada

NASA Astrophysics Data System (ADS)

Kopylova, Maya G.; Russell, James K.

2000-08-01

We describe the mineralogical and chemical composition of the Northern Slave mantle as deduced from xenoliths of peridotite within the Jericho kimberlite, Northwest Territories. Our data set includes modal, major, trace and rare earth element compositions of bulk samples of spinel peridotite, low-T and high-T garnet peridotite and minor pyroxenite. Compared to primitive upper mantle, Jericho peridotite shows depletion in the major elements and enrichment in incompatible elements (except for HREE). The Slave mantle is also uniquely stratified. Older, depleted spinel peridotite extends to a depth of 80-100 km and is underlain by garnet peridotite which shows a gradual decrease in Mg# with depth to 200 km. The youngest layer of fertile garnet peridotite, enriched in clinopyroxene and garnet, is underlain by a pyroxenite-rich horizon at the base of the petrological lithosphere. The Northern Slave is further distinguished from the Kaapvaal and Siberian upper mantle by a marked vertical stratification in Mg#, lower abundances of orthopyroxene and higher abundances of clinopyroxene. In addition, a deeper layer of garnet peridotite below Jericho shows less depletion than low-T peridotite from other cratons. The Northern Slave peridotite results from a series of chemical events that include: (i) high-degree melting of pyrolite at P>3 Gpa for low-T peridotite and lower pressure melting for high-T peridotite, (ii) enrichment of low-T spinel peridotite in orthopyroxene, and (iii) pervasive metasomatic enrichment in alkali and LREE's by kimberlite-related fluids. The chemical stratification described for two of the three lithospheric domains of the Slave craton makes this craton an exception among cratons with commonly unstratified lithospheres. The gradual increase in fertility with depth below the Slave craton is related to age stratification and may have formed by incremental downward growth of mantle lithosphere with time, and/or later re-fertilization of deeper mantle

Social Stratification and Mobility in a Rural Community (Mahi) in Gujarat, India.

ERIC Educational Resources Information Center

Panchanadikar, K. C.; Panchanadikar, J.

Analyzing the interaction between factors that are stable and factors that initiate change re: promotion of social mobility or crystalization of existing social stratification, this paper presents a case study of Mahi, a rural village in Gujarat, India. Utilizing data derived from two field studies (1961-1962 and March 1967-June 1967), the stable…

Boiling water scarification plus stratification improves germination of Iliamna rivularis (Malvaceae) seeds

Treesearch

Katri Himanen; Markku Nygren; R. Kasten Dumroese

2012-01-01

Scarification with boiling water plus stratification was most effective in improving germination of Iliamna rivularis (Douglas ex Hook.) Greene (Malvaceae) in an experiment that compared 3 treatments. Seeds from 15 sites representing 5 western US states were used in the experiment. Initial response of the seedlots to the treatments was similar, apart from one seedlot....

Wave Propagation Around Coronal Structures: Stratification, Buoyancy, Small Scale Formation

NASA Astrophysics Data System (ADS)

Tomlinson, S. M.; Rappazzo, F.; Velli, M.

2017-12-01

We study the propagation of waves in a coronal medium characterized by stratification and structure in density. temperature and magnetic field. It is well known that average gradients affect the propagation of Alfvén and other MHD waves via reflection, phase mixing, resonant absorption and other coupling phenomena. Here we discuss how the interplay of propagation on inhomogeneous, stratified structures with nonlinear interactions may lead to interesting effects including preferential heating, buoyancy, and plasma acceleration.

Ionic Size Effects: Generalized Boltzmann Distributions, Counterion Stratification, and Modified Debye Length.

PubMed

Liu, Bo; Liu, Pei; Xu, Zhenli; Zhou, Shenggao

2013-10-01

Near a charged surface, counterions of different valences and sizes cluster; and their concentration profiles stratify. At a distance from such a surface larger than the Debye length, the electric field is screened by counterions. Recent studies by a variational mean-field approach that includes ionic size effects and by Monte Carlo simulations both suggest that the counterion stratification is determined by the ionic valence-to-volume ratios. Central in the mean-field approach is a free-energy functional of ionic concentrations in which the ionic size effects are included through the entropic effect of solvent molecules. The corresponding equilibrium conditions define the generalized Boltzmann distributions relating the ionic concentrations to the electrostatic potential. This paper presents a detailed analysis and numerical calculations of such a free-energy functional to understand the dependence of the ionic charge density on the electrostatic potential through the generalized Boltzmann distributions, the role of ionic valence-to-volume ratios in the counterion stratification, and the modification of Debye length due to the effect of ionic sizes.

Ionic Size Effects: Generalized Boltzmann Distributions, Counterion Stratification, and Modified Debye Length

PubMed Central

Liu, Bo; Liu, Pei; Xu, Zhenli; Zhou, Shenggao

2013-01-01

Near a charged surface, counterions of different valences and sizes cluster; and their concentration profiles stratify. At a distance from such a surface larger than the Debye length, the electric field is screened by counterions. Recent studies by a variational mean-field approach that includes ionic size effects and by Monte Carlo simulations both suggest that the counterion stratification is determined by the ionic valence-to-volume ratios. Central in the mean-field approach is a free-energy functional of ionic concentrations in which the ionic size effects are included through the entropic effect of solvent molecules. The corresponding equilibrium conditions define the generalized Boltzmann distributions relating the ionic concentrations to the electrostatic potential. This paper presents a detailed analysis and numerical calculations of such a free-energy functional to understand the dependence of the ionic charge density on the electrostatic potential through the generalized Boltzmann distributions, the role of ionic valence-to-volume ratios in the counterion stratification, and the modification of Debye length due to the effect of ionic sizes. PMID:24465094

Turbulence and pollutant transport in urban street canyons under stable stratification: a large-eddy simulation

NASA Astrophysics Data System (ADS)

Li, X.

2014-12-01

Thermal stratification of the atmospheric surface layer has strong impact on the land-atmosphere exchange of turbulent, heat, and pollutant fluxes. Few studies have been carried out for the interaction of the weakly to moderately stable stratified atmosphere and the urban canopy. This study performs a large-eddy simulation of a modeled street canyon within a weakly to moderately stable atmosphere boundary layer. To better resolve the smaller eddy size resulted from the stable stratification, a higher spatial and temporal resolution is used. The detailed flow structure and turbulence inside the street canyon are analyzed. The relationship of pollutant dispersion and Richardson number of the atmosphere is investigated. Differences between these characteristics and those under neutral and unstable atmosphere boundary layer are emphasized.

Changes in endogenous plant hormones and 'H-NMR profiles and signals in Styrax japonicus seeds as influenced by warm and cold stratification

USDA-ARS?s Scientific Manuscript database

Germination of Styrax japonicus Sieb. et. Zucc. seeds was promoted by warm stratification (WS) at around 20 °C followed by cold stratification (CS) at around 5oC. Biochemical and physiological changes in Styrax seeds during these WS and CS treatments were not investigated. The objective of this wo...

Histological Stratification of Thick and Thin Plaque Psoriasis Explores Molecular Phenotypes with Clinical Implications

PubMed Central

Kim, Dong Joo; Brodmerkel, Carrie; Correa da Rosa, Joel; Krueger, James G.; Suárez-Fariñas, Mayte

2015-01-01

Psoriasis, which presents as red, scaly patches on the body, is a common, autoimmune skin disease that affects 2 to 3 percent of the world population. To leverage recent molecular findings into the personalized treatment of psoriasis, we need a strategy that integrates clinical stratification with molecular phenotyping. In this study, we sought to stratify psoriasis patients by histological measurements of epidermal thickness, and to compare their molecular characterizations by gene expression, serum cytokines, and response to biologics. We obtained histological measures of epidermal thickness in a cohort of 609 psoriasis patients, and identified a mixture of two subpopulations—thick and thin plaque psoriasis—from which they were derived. This stratification was verified in a subcohort of 65 patients from a previously published study with significant differences in inflammatory cell infiltrates in the psoriatic skin. Thick and thin plaque psoriasis shared 84.8% of the meta-analysis-derived psoriasis transcriptome, but a stronger dysregulation of the meta-analysis-derived psoriasis transcriptome was seen in thick plaque psoriasis on microarray. RT-PCR revealed that gene expression in thick and thin plaque psoriasis was different not only within psoriatic lesional skin but also in peripheral non-lesional skin. Additionally, differences in circulating cytokines and their changes in response to biologic treatments were found between the two subgroups. All together, we were able to integrate histological stratification with molecular phenotyping as a way of exploring clinical phenotypes with different expression levels of the psoriasis transcriptome and circulating cytokines. PMID:26176783

Structural Analysis of a Consumption-Based Stratification Indicator: Relational Proximity of Household Expenditures

ERIC Educational Resources Information Center

Katz-Gerro, Tally; Talmud, Ilan

2005-01-01

This paper proposes a new analysis of consumption inequality using relational methods, derived from network images of social structure. We combine structural analysis with theoretical concerns in consumer research to propose a relational theory of consumption space, to construct a stratification indicator, and to demonstrate its analytical…

School Choice, Gentrification, and the Variable Significance of Racial Stratification in Urban Neighborhoods

ERIC Educational Resources Information Center

Pearman, Francis A., III; Swain, Walker A.

2017-01-01

Racial and socioeconomic stratification have long governed patterns of residential sorting in the American metropolis. However, recent expansions of school choice policies that allow parents to select schools outside their neighborhood raise questions as to whether this weakening of the neighborhood-school connection might influence the…

Ancestral haplotype-based association mapping with generalized linear mixed models accounting for stratification.

PubMed

Zhang, Z; Guillaume, F; Sartelet, A; Charlier, C; Georges, M; Farnir, F; Druet, T

2012-10-01

In many situations, genome-wide association studies are performed in populations presenting stratification. Mixed models including a kinship matrix accounting for genetic relatedness among individuals have been shown to correct for population and/or family structure. Here we extend this methodology to generalized linear mixed models which properly model data under various distributions. In addition we perform association with ancestral haplotypes inferred using a hidden Markov model. The method was shown to properly account for stratification under various simulated scenari presenting population and/or family structure. Use of ancestral haplotypes resulted in higher power than SNPs on simulated datasets. Application to real data demonstrates the usefulness of the developed model. Full analysis of a dataset with 4600 individuals and 500 000 SNPs was performed in 2 h 36 min and required 2.28 Gb of RAM. The software GLASCOW can be freely downloaded from www.giga.ulg.ac.be/jcms/prod_381171/software. francois.guillaume@jouy.inra.fr Supplementary data are available at Bioinformatics online.

Stratification Modelling of Key Bacterial Taxa Driven by Metabolic Dynamics in Meromictic Lakes.

PubMed

Zhu, Kaicheng; Lauro, Federico M; Su, Haibin

2018-06-22

In meromictic lakes, the water column is stratified into distinguishable steady layers with different physico-chemical properties. The bottom portion, known as monimolimnion, has been studied for the functional stratification of microbial populations. Recent experiments have reported the profiles of bacterial and nutrient spatial distributions, but quantitative understanding is invoked to unravel the underlying mechanism of maintaining the discrete spatial organization. Here a reaction-diffusion model is developed to highlight the spatial pattern coupled with the light-driven metabolism of bacteria, which is resilient to a wide range of dynamical correlation between bacterial and nutrient species at the molecular level. Particularly, exact analytical solutions of the system are presented together with numerical results, in a good agreement with measurements in Ace lake and Rogoznica lake. Furthermore, one quantitative prediction is reported here on the dynamics of the seasonal stratification patterns in Ace lake. The active role played by the bacterial metabolism at microscale clearly shapes the biogeochemistry landscape of lake-wide ecology at macroscale.

[Comparison of the present and previously used protocol of risk stratification in children with acute lymphoblastic leukemia].

PubMed

Glodkowska, Eliza; Bialas, Agnieszka; Jackowska, Teresa

2007-01-01

Acute lymphoblastic leukaemia (ALL) is one of the most common cancers in children. In Poland, since November 2002 a new protocol of risk stratification has been recommended for assessment of risk factors and for choosing therapy regimens. assessment of accuracy of protocol ALL-IC 2002 in comparison to previously used risk stratification protocols. ALL was diagnosed in 100 children (44 girls, 56 boys; 1-18 years of age) in the Department of Pediatric Hematology and Oncology, Warsaw Medical University, over the period from November 2002 to November 2006. According to the ALL-IC 2002 protocol the patients were divided into three risk groups: SR-standard, IR-intermediate and HR-high. The stratification was by age, leukocyte count, cytogenetic changes, early response to prednisone therapy and bone marrow remission. In the previously used risk stratification protocols-BFM-90, only hepatosplenomegaly and the number of blasts in peripheral blood (PB) were considered, and the patients were divided into three risk groups: low (LRG<0.8), medium (MRG) and high (HRG>1.2). out of the 100 patients qualified for treatment regimens according to the ALL-IC 2002 protocol, 97 entered remission, 11 died and 3 had a relapse. Under the ALL-IC 2002 protocol these children were stratified into the following groups: SR-31%, IR-44% and HR-25%. In the previously used stratification, there would be 26% children in low, 46% in the medium and 28% in the high risk group. According to the BFM-90 protocol 18/31 (58%) and 16/44 (36%) patients from the SR and IR groups respectively would be given more intensive treatment. On the other hand 11/44 (25%) and 14/25 (56%) patients from the IR and HR groups respectively would be given less intensive treatment. 1. ALL-IC 2002 protocol in comparison with the previously used protocol BFM-90, changes the qualification of children with ALL for the SR, IR and HR risk groups. This is linked to basic change of treatment protocol, adequate to severity of disease. 2

The Auckland Cataract Study II: Reducing Complications by Preoperative Risk Stratification and Case Allocation in a Teaching Hospital.

PubMed

Kim, Bia Z; Patel, Dipika V; McKelvie, James; Sherwin, Trevor; McGhee, Charles N J

2017-09-01

To assess the effect of preoperative risk stratification for phacoemulsification surgery on intraoperative complications in a teaching hospital. Prospective cohort study. Prospective assessment of consecutive phacoemulsification cases (N = 500) enabled calculation of a risk score (M-score of 0-8) using a risk stratification system. M-scores of >3 were allocated to senior surgeons. All surgeries were performed in a public teaching hospital setting, Auckland, New Zealand, in early 2016. Postoperatively, data were reviewed for complications and corrected distance visual acuity (CDVA). Results were compared to a prospective study (N = 500, phase 1) performed prior to formal introduction of risk stratification. Intraoperative complications increased with increasing M-scores (P = .044). Median M-score for complicated cases was higher (P = .022). Odds ratio (OR) for a complication increased 1.269 per unit increase in M-score (95% confidence interval [CI] 1.007-1.599, P = .043). Overall rate of any intraoperative complication was 5.0%. Intraoperative complication rates decreased from 8.4% to 5.0% (OR = 0.576, P = .043) comparing phase 1 and phase 2 (formal introduction of risk stratification). The severity of complications also reduced. A significant decrease in complications for M = 0 (ie, minimal risk cases) was also identified comparing the current study (3.1%) to phase 1 (7.2%), P = .034. There was no change in postoperative complication risks (OR 0.812, P = .434) or in mean postoperative CDVA (20/30, P = .484) comparing current with phase 1 outcomes. A simple preoperative risk stratification system, based on standard patient information gathered at preoperative consultation, appears to reduce intraoperative complications and support safer surgical training by appropriate allocation of higher-risk cases. Copyright © 2017 Elsevier Inc. All rights reserved.

Une complication rare des léiomyomes utérins: hémopéritoine massif par rupture de varices

PubMed Central

Ymele, Florent Fouelifack; Tsuala, Jovanny Fouogue; Fouedjio, Jeanne Hortence; Nangué, Charlette; De Kayo, Caroline Kayo; Dobgima, Pisoh Walter; Mbu, Robinson Enoh

2013-01-01

Les léiomyomes utérins sont des causes exceptionnelles d'hémopéritoine. Nous rapportons ici le cas d'une femme de 46 ans nullipare, en instance d'une hystérectomie totale indiquée pour utérus polymyomateux symptomatique. Elle a été opérée en urgence pour hémopéritoine aigu et massif compliqué de choc hémorragique. L'origine de l'hémopéritoine était la rupture spontanée d'une varice du léiomyome. Quoique rare l'éventualité d'un hémopéritoine causé par un fibrome utérin devrait être évoquée devant tout abdomen aigu spontané chez une femme en âge de procréer. La présence de varices sur les fibromes augmenterait le risque d'hémorragie spontanée. PMID:23717724

A new gender-specific model for skin autofluorescence risk stratification

PubMed Central

Ahmad, Muhammad S.; Damanhouri, Zoheir A.; Kimhofer, Torben; Mosli, Hala H.; Holmes, Elaine

2015-01-01

Advanced glycation endproducts (AGEs) are believed to play a significant role in the pathophysiology of a variety of diseases including diabetes and cardiovascular diseases. Non-invasive skin autofluorescence (SAF) measurement serves as a proxy for tissue accumulation of AGEs. We assessed reference SAF and skin reflectance (SR) values in a Saudi population (n = 1,999) and evaluated the existing risk stratification scale. The mean SAF of the study cohort was 2.06 (SD = 0.57) arbitrary units (AU), which is considerably higher than the values reported for other populations. We show a previously unreported and significant difference in SAF values between men and women, with median (range) values of 1.77 AU (0.79–4.84 AU) and 2.20 AU (0.75–4.59 AU) respectively (p-value « 0.01). Age, presence of diabetes and BMI were the most influential variables in determining SAF values in men, whilst in female participants, SR was also highly correlated with SAF. Diabetes, hypertension and obesity all showed strong association with SAF, particularly when gender differences were taken into account. We propose an adjusted, gender-specific disease risk stratification scheme for Middle Eastern populations. SAF is a potentially valuable clinical screening tool for cardiovascular risk assessment but risk scores should take gender and ethnicity into consideration for accurate diagnosis. PMID:25974028

Apollo oxygen tank stratification analysis, volume 2

NASA Technical Reports Server (NTRS)

Barton, J. E.; Patterson, H. W.

1972-01-01

An analysis of flight performance of the Apollo 15 cryogenic oxygen tanks was conducted with the variable grid stratification math model developed earlier in the program. Flight conditions investigated were the CMP-EVA and one passive thermal control period which exhibited heater temperature characteristics not previously observed. Heater temperatures for these periods were simulated with the math model using flight acceleration data. Simulation results (heater temperature and tank pressure) compared favorably with the Apollo 15 flight data, and it was concluded that tank performance was nominal. Math model modifications were also made to improve the simulation accuracy. The modifications included the addition of the effects of the tank wall thermal mass and an improved system flow distribution model. The modifications improved the accuracy of simulated pressure response based on comparisons with flight data.

Approche aux soins en milieu communautaire à des adultes ayant une déficience développementale

PubMed Central

Osmun, W.E.; Chan, Nelson; Solomon, Robert

2015-01-01

Résumé Objectif Passer en revue les obligations d’ordre médical, éthique et juridique dans les soins aux adultes ayant une déficience développementale (DD) qui vivent dans la communauté. Sources des données Des recherches ont été faites dans Google et MEDLINE à l’aide des mots disabled, disability, vulnerable et community. Les lois pertinentes ont fait l’objet d’un examen. Message principal Le traitement d’un patient ayant une DD varie en fonction de facteurs comme la pathogenèse du problème actuel du patient, ses affections concomitantes, la gravité de ses déficiences et ses soutiens sociaux habituels. Bien que l’on s’entende sur les bienfaits du transfert des soins institutionnels vers des soins communautaires pour les patients ayant une DD, il s’est révélé difficile de leur dispenser des soins de grande qualité en milieu communautaire. Par ailleurs, il existe peu de travaux de recherche sur les façons d’offrir efficacement des soins aux adultes ayant une DD. En tant que professionnels des soins primaires, les médecins de famille sont souvent le premier point de contact pour les patients et sont à la fois responsables de la coordination et de la continuité des soins. Compte tenu de l’importance accrue accordée aux soins préventifs et à la détection précoce des maladies, la participation active du patient revêt aussi une grande importance. Les valeurs et les objectifs du patient sont des éléments essentiels à prendre en compte, même s’ils vont à l’encontre de la bonne santé du patient ou des propres valeurs du clinicien. Les lois s’appliquant aux personnes vulnérables varient d’une province à l’autre. Par conséquent, l’obligation de signaler des mauvais traitements suspectés pourrait différer selon que la personne vulnérable habite dans un centre de soins ou la communauté, que la personne qui soupçonne le comportement abusif est un fournisseur de services ou un professionnel de la santé ou

Risk stratification using lean body mass in patients undergoing transcatheter aortic valve replacement.

PubMed

Hioki, Hirofumi; Watanabe, Yusuke; Kozuma, Ken; Yamamoto, Masanori; Naganuma, Toru; Araki, Motoharu; Tada, Norio; Shirai, Shinichi; Yamanaka, Futoshi; Higashimori, Akihiro; Mizutani, Kazuki; Tabata, Minoru; Takagi, Kensuke; Ueno, Hiroshi; Hayashida, Kentaro

2018-02-22

The prognostic impact of skeletal muscle mass, assessed using lean body mass (LBM), remain unclear in patients who underwent transcatheter aortic valve replacement (TAVR). The aim of this study to assess prognostic impact of LBM on mortality after TAVR. We assessed 1,613 patients (median age 85 years, 70% female) who underwent TAVI from October 2013 to April 2016 using OCEAN (Optimized transCathEter vAlvular interveNtion)-TAVI registry data. LBM was calculated using the James formula. The primary endpoint was all-cause death after TAVR. Median follow-up period was 287 days (interquartile range 110-462). The Kaplan-Meier analysis demonstrated that patients with low LBM had significantly higher incidence of all-cause death than those with high LBM in male (32.3% vs. 9.9%, log rank P < 0.001) and female (15.8% vs. 9.2%, log-rank P = 0.011). On contrary, the risk stratification using body mass index (BMI) could not validate into female patients who underwent TAVR. The multivariate analysis showed that the LBM was an independent predictor of all-cause death in male (Hazard ratio [HR] 0.93; 95% confidence interval [CI] 0.89-0.98) and female (HR 0.94; 95% CI 0.89-0.99). Inversely, the assessment using BMI could not identify the high-risk population in a female. The patients with low LBM had the higher incidence of all-cause death after TAVR than those with high LBM, regardless of gender. Thus, the risk stratification using LBM might provide further insight to identify the high-risk TAVR population, compared to conventional risk stratification using BMI. © 2018 Wiley Periodicals, Inc.

Risk stratification and staging in prostate cancer with prostatic specific membrane antigen PET/CTObjective: A one-stop-shop.

PubMed

Gupta, Manoj; Choudhury, Partha Sarathi; Rawal, Sudhir; Goel, Harish Chandra; Singh, Amitabh; Talwar, Vineet; Sahoo, Saroj Kumar

2017-01-01

Current imaging modalities for prostate cancer (PC) had limitations for risk stratification and staging. Magnetic resonance imaging (MRI) frequently underestimated lymphatic metastasis while bone scintigraphy often had diagnostic dilemmas. Prostatic specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET/CT) has been remarkable in diagnosing PC recurrence and staging. We hypothesized it can become one-stop-shop for initial risk stratification and staging. Ninety seven PSMA PET-CT studies were re analysed for tumor node metastases (TNM) staging and risk stratification of lymphatic and distant metastases proportion. The histopathology of 23/97 patients was available as gold standard. Chi-square test was used for proportion comparison. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), over-estimation, under-estimation and correct-estimation of T and N stages were calculated. Cohen's kappa coefficient (k) was derived for inter-rater agreement. Lymphic or distant metastases detection on PSMA PET/CT increased significantly with increase in risk category. PSMA PET/CT sensitivity, specificity, PPV and NPV for extra prostatic extension (EPE), seminal vesicle invasion (SVI) and lymphatic metastases were 63.16%, 100%, 100%, 36.36% & 55%, 100%, 100%, 25% and 65.62%, 99.31%, 87.50%, 97.53%, respectively. Cohen's kappa coefficient showed substantial agreement between PSMA PET/CT and histopathological lymphic metastases (κ 0.734) however, it was just in fair agreement (κ 0.277) with T stage. PSMA PET/CT over-estimated, under-estimated and correct-estimated T and N stages in 8.71%, 39.13%, 52.17% and 8.71%, 4.35%, 86.96% cases, respectively. We found that PSMA PET/CT has potential for initial risk stratifications with reasonable correct estimation for N stage. However, it can underestimate T stage. Hence, we suggest that PSMA PET/CT should be used for staging and initial risk stratification of PC as one

Influences of Ocean Thermohaline Stratification on Arctic Sea Ice

NASA Astrophysics Data System (ADS)

Toole, J. M.; Timmermans, M.-L.; Perovich, D. K.; Krishfield, R. A.; Proshutinsky, A.; Richter-Menge, J. A.

2009-04-01

The Arctic Ocean's surface mixed layer constitutes the dynamical and thermodynamical link between the sea ice and the underlying waters. Wind stress, acting directly on the surface mixed layer or via wind-forced ice motion, produce surface currents that can in turn drive deep ocean flow. Mixed layer temperature is intimately related to basal sea ice growth and melting. Heat fluxes into or out of the surface mixed layer can occur at both its upper and lower interfaces: the former via air-sea exchange at leads and conduction through the ice, the latter via turbulent mixing and entrainment at the layer base. Variations in Arctic Ocean mixed layer properties are documented based on more than 16,000 temperature and salinity profiles acquired by Ice-Tethered Profilers since summer 2004 and analyzed in conjunction with sea ice observations from Ice Mass Balance Buoys and atmospheric heat flux estimates. Guidance interpreting the observations is provided by a one-dimensional ocean mixed layer model. The study focuses attention on the very strong density stratification about the mixed layer base in the Arctic that, in regions of sea ice melting, is increasing with time. The intense stratification greatly impedes mixed layer deepening by vertical convection and shear mixing, and thus limits the flux of deep ocean heat to the surface that could influence sea ice growth/decay. Consistent with previous work, this study demonstrates that the Arctic sea ice is most sensitive to changes in ocean mixed layer heat resulting from fluxes across its upper (air-sea and/or ice-water) interface.

Investigating Stratification within Higher Education through Examining the Status of Students in Different Academic Majors in Terms of Cultural, Social and Economic Capital

ERIC Educational Resources Information Center

Hassani, Mohammad; Ghasemi, Seyyed Jamal Mir

2016-01-01

This study was carried out in order to explore the status of stratification within higher education through measuring cultural, economic and social capital of students in major academic disciplines across universities in Urmia, Northwestern Iran. The findings indicate that there are stratification structures in the presence of students in…

Mortality risk stratification in severely anaemic Jehovah's Witness patients.

PubMed

Beliaev, A M; Marshall, R J; Smith, W; Windsor, J A

2012-03-01

The aim of this retrospective cohort study was to identify early risk factors of mortality and develop a mortality risk stratification instrument for severely anaemic Jehovah's Witness patients. It has been shown that Jehovah's Witness patients with the Auckland Anaemia Mortality Risk Score (Auckland AMRS) of 0 to 3 had 4% mortality, Auckland AMRS 4 to 5 32%, Auckland AMRS 6 to 7 50% and Auckland AMRS 8 and above 83%. It is concluded that the Auckland AMRS predicts mortality of severely anaemic Jehovah's Witness patients. © 2012 The Authors. Internal Medicine Journal © 2012 Royal Australasian College of Physicians.

Research in progress: Medical Research Council United Kingdom Refractory Asthma Stratification Programme (RASP-UK).

PubMed

Heaney, Liam G; Djukanovic, Ratko; Woodcock, Ashley; Walker, Samantha; Matthews, John G; Pavord, Ian D; Bradding, Peter; Niven, Robert; Brightling, Chris E; Chaudhuri, Rekha; Arron, Joseph R; Choy, David F; Cowan, Douglas; Mansur, Adel; Menzies-Gow, Andrew; Adcock, Ian; Chung, Kian F; Corrigan, Chris; Coyle, Peter; Harrison, Timothy; Johnston, Sebastian; Howarth, Peter; Lordan, James; Sabroe, Ian; Bigler, Jeannette; Smith, Dirk; Catley, Matthew; May, Richard; Pierre, Lisa; Stevenson, Chris; Crater, Glenn; Keane, Frank; Costello, Richard W; Hudson, Val; Supple, David; Hardman, Tim

2016-02-01

The UK Refractory Asthma Stratification Programme (RASP-UK) will explore novel biomarker stratification strategies in severe asthma to improve clinical management and accelerate development of new therapies. Prior asthma mechanistic studies have not stratified on inflammatory phenotype and the understanding of pathophysiological mechanisms in asthma without Type 2 cytokine inflammation is limited. RASP-UK will objectively assess adherence to corticosteroids (CS) and examine a novel composite biomarker strategy to optimise CS dose; this will also address what proportion of patients with severe asthma have persistent symptoms without eosinophilic airways inflammation after progressive CS withdrawal. There will be interactive partnership with the pharmaceutical industry to facilitate access to stratified populations for novel therapeutic studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Running in Place: Low-Income Students and the Dynamics of Higher Education Stratification

ERIC Educational Resources Information Center

Bastedo, Michael N.; Jaquette, Ozan

2011-01-01

The increasing concentration of wealthy students at highly selective colleges is widely perceived, but few analyses examine the underlying dynamics of higher education stratification over time. To examine these dynamics, the authors build an analysis data set of four cohorts from 1972 to 2004. They find that low-income students have made…

Cause rare d’insuffisance rénale aigue: géant calcul de vessie chez une jeune femme

PubMed Central

Mohammed, Bounoual; Mustapha, Ahsaini; Karim, Tazi; Hamid, Azelmad; Mohammed, Alila; Soufiane, Mellas; eddine, El Ammari Jalal; Fadl, Tazi Mohammed; Jamal, El Fassi Mohammed; Hassan, Farih Moulay

2018-01-01

Géant calcul de vessie se définit par un poids supérieur à 100 g, c'est une pathologie rare chez la femme, environ 2%. La localisation vésicale ne dépasse pas 5% de l'ensemble des voies urinaires. Chez la femme l'apparition de calcul de vessie est souvent secondaire à un facteur prédisposant notamment un corps étranger intra vésical, vessie neurogene, les infections urinaires à répétition, ATCDS de chirurgie de l'incontinence urinaire d'effort. Mais on retrouve des calculs de vessie sans causes évidentes dits calculs primaires idiopathiques. On rapporte un cas d'une jeune patiente de 31 ans avec un géant calcul de vessie qui a retenti sur le haut appareil urinaire entrainant une insuffisance rénale aigue. La patiente a bénéficié initialement d'un drainage de haut appareil urinaire par des néphrostomies bilatérales puis elle a bénéficié d'une cystolithotomie à ciel ouvert d'un gros calcul de vessie. Un bilan étiologique a été demandé pourtant n'a pas identifié de cause évidente. PMID:29632626

Une cause rare de compression médullaire: kyste arachnoïdien épidural rachidien (à propos de 03 cas)

PubMed Central

El Saqui, Abderrazzak; Aggouri, Mohamed; Benzagmout, Mohamed; Chakour, Khalid; Chaoui, Mohamed El Faiz

2017-01-01

Le kyste arachnoïdien épidural rachidien (KAER) est une affection bénigne, de physiopathologie encore incertaine. Il est le plus souvent asymptomatique mais peut causer des séquelles neurologiques graves surtout quand le traitement n'est pas instauré à temps. Nous rapportons l'expérience du service de Neurochirurgie CHU Hassan II- Fès concernant la prise en charge du KAER à travers l'analyse rétrospective de trois cas. Il s'agit de deux patients de sexe masculin et d'une femme, d'âge moyen de 35 ans (Extrêmes: 16 et 56 ans), tous admis pour un tableau de compression médullaire lente. Tous nos patients ont bénéficié d'une IRM médullaire qui a mis en évidence une collection liquidienne de siège épidural, ayant le même signal que le LCR, comprimant la moelle en regard. Le siège de la collection était thoracique dans tous les cas. Tous nos patients ont été opérés par voie postérieure avec exérèse du kyste et ligature du collet dans deux cas et une plastie durale dans un seul cas. L'étude anatomopathologique a conclu en un kyste arachnoïdien. L'évolution postopératoire était favorable dans tous les cas. Ce travail a comme objectif de mettre le point sur cette pathologie tout en insistant sur la nécessité d'une prise en charge précoce, vu la tendance vers l'aggravation progressive en l'absence de thérapie adaptée et rappeler les particularités cliniques, paracliniques et thérapeutiques de cette affection. PMID:28533855

Modélisation des charges d'espace dans les isolants solides par une analyse spectrale

NASA Astrophysics Data System (ADS)

Haas, V.; Scouarnec, Ch.; Franceschi, J. L.

1998-01-01

A mathematical method based on spectral algebra is developped for the thermal modulation method. These methods permit to measure the space charge distribution in solid insulators. The modelling presented permits to evaluate the performances and the limitations of the measurement method. Une linéarisation par l'algèbre spectrale a été développée dans une méthode de modulation thermique pour mesurer la distribution des charges électriques dans les isolants solides. La modélisation présentée permet d'évaluer les performances et les limites tant numériques que physiques de la méthode de mesure.

Study of thermal and hydraulic efficiency of supersonic tube of temperature stratification

NASA Astrophysics Data System (ADS)

Tsynaeva, Anna A.; Nikitin, Maxim N.; Tsynaeva, Ekaterina A.

2017-10-01

Efficiency of supersonic pipe for temperature stratification with finned subsonic surface of heat transfer is the major of this paper. Thermal and hydraulic analyses of this pipe were conducted to asses effects from installation of longitudinal rectangular and parabolic fins as well as studs of cylindrical, rectangular and parabolic profiles. The analysis was performed based on refined empirical equations of similarity, dedicated to heat transfer of high-speed gas flow with plain wall, and Kármán equation with Nikuradze constants. Results revealed cylindrical studs (with height-to-diameter ratio of 5:1) to be 1.5 times more efficient than rectangular fins of the same height. At the same time rectangular fins (with height-to-thickness ratio of 5:1) were tend to enhance heat transfer rate up to 2.67 times compared to bare walls from subsonic side of the pipe. Longitudinal parabolic fins have minuscule effect on combined efficiency of considered pipe since extra head losses void any gain of heat transfer. Obtained results provide perspective of increasing efficiency of supersonic tube for temperature stratification. This significantly broadens device applicability in thermostatting systems for equipment, cooling systems for energy converting machinery, turbine blades and aerotechnics.

Methodologie de modelisation aerostructurelle d'une aile utilisant un logiciel de calcul aerodynamique et un logiciel de calcul par elements finis =

NASA Astrophysics Data System (ADS)

Communier, David

Lors de l'etude structurelle d'une aile d'avion, il est difficile de modeliser fidelement les forces aerodynamiques subies par l'aile de l'avion. Pour faciliter l'analyse, on repartit la portance maximale theorique de l'aile sur son longeron principal ou sur ses nervures. La repartition utilisee implique que l'aile entiere sera plus resistante que necessaire et donc que la structure ne sera pas totalement optimisee. Pour pallier ce probleme, il faudrait s'assurer d'appliquer une repartition aerodynamique de la portance sur la surface complete de l'aile. On serait donc en mesure d'obtenir une repartition des charges sur l'aile beaucoup plus fiable. Pour le realiser, nous aurons besoin de coupler les resultats d'un logiciel calculant les charges aerodynamiques de l'aile avec les resultats d'un logiciel permettant sa conception et son analyse structurelle. Dans ce projet, le logiciel utilise pour calculer les coefficients de pression sur l'aile est XFLR5 et le logiciel permettant la conception et l'analyse structurelle sera CATIA V5. Le logiciel XFLR5 permet une analyse rapide d'une aile en se basant sur l'analyse de ses profils. Ce logiciel calcule les performances des profils de la meme maniere que XFOIL et permet de choisir parmi trois methodes de calcul pour obtenir les performances de l'aile : Lifting Line Theory (LLT), Vortex Lattice Method (VLM) et 3D Panels. Dans notre methodologie, nous utilisons la methode de calcul 3D Panels dont la validite a ete testee en soufflerie pour confirmer les calculs sur XFLR5. En ce qui concerne la conception et l'analyse par des elements finis de la structure, le logiciel CATIA V5 est couramment utilise dans le domaine aerospatial. CATIA V5 permet une automatisation des etapes de conception de l'aile. Ainsi, dans ce memoire, nous allons decrire la methodologie permettant l'etude aerostructurelle d'une aile d'avion.

Etude microdosimetrique de l'influence des materiaux sur l'efficacite biologique d'une source d'iode-125

NASA Astrophysics Data System (ADS)

Taschereau, Richard

Cette these concerne les implants permanents pour la prostate. Les isotopes employes, le 103Pd et l'125I, semblent produire les memes resultats cliniques: le premier a cause d'une radiation plus efficace et le second a cause de sa demi-vie plus longue. La recherche utilise le cadre theorique de la microdosimetrie et des simulations Monte Carlo. Elle propose d'employer le spectre d'ejection dans le calcul de l'efficacite; ce changement fait passer l'efficacite relative du 103Pd de 10% a 5%. Elle montre ensuite qu'il est possible d'ameliorer l'efficacite de la radiation de 125I par l'exploitation des rayons X caracteristiques de la capsule. Une source amelioree faite de molybdene et d'yttrium est donnee en exemple. Elle procure une radiation de 5--7% plus efficace, ce qui surclasse les deux sources existantes. Les applications ne se limitent pas au traitement de la prostate; le traitement du melanome oculaire et la curietherapie endovasculaire pourraient en beneficier.

Standardized reporting guidelines for emergency department syncope risk-stratification research.

PubMed

Sun, Benjamin C; Thiruganasambandamoorthy, Venkatesh; Cruz, Jeffrey Dela

2012-06-01

There is increasing research interest in the risk stratification of emergency department (ED) syncope patients. A major barrier to comparing and synthesizing existing research is wide variation in the conduct and reporting of studies. The authors wanted to create standardized reporting guidelines for ED syncope risk-stratification research using an expert consensus process. In that pursuit, a panel of syncope researchers was convened and a literature review was performed to identify candidate reporting guideline elements. Candidate elements were grouped into four sections: eligibility criteria, outcomes, electrocardiogram (ECG) findings, and predictors. A two-round, modified Delphi consensus process was conducted using an Internet-based survey application. In the first round, candidate elements were rated on a five-point Likert scale. In the second round, panelists rerated items after receiving information about group ratings from the first round. Items that were rated by >80% of the panelists at the two highest levels of the Likert scale were included in the final guidelines. There were 24 panelists from eight countries who represented five clinical specialties. The panel identified an initial set of 183 candidate elements. After two survey rounds, the final reporting guidelines included 92 items that achieved >80% consensus. These included 10 items for study eligibility, 23 items for outcomes, nine items for ECG abnormalities, and 50 items for candidate predictors. Adherence to these guidelines should facilitate comparison of future research in this area. © 2012 by the Society for Academic Emergency Medicine.

Etude par Imagerie à faible Niveau dans le proche Infrarouge d'une Emission de la haute Atmosphère

NASA Astrophysics Data System (ADS)

Pautet, Pierre-Dominique

2000-12-01

Le travail effectué a eu pour but la mise en place d'un protocole d'observation et de traitement des images, ainsi que les outils appropriés, visant à l'étude d'une émission de la haute atmosphère terrestre dans le proche infrarouge. Il existe actuellement des télescopes comme le VLT (Very Large Telescope), installé au Chili, qui permettent d'observer des astres et des galaxies distants de plusieurs millions de parsecs. A cause de l'expansion de l'Univers, des objets situés aussi loin s'éloignent très rapidement de nous. Le spectre de leur émission qui nous parvient alors est décalé vers le rouge ou l'infrarouge, du fait de l'effet Doppler. Il faut donc observer ces objets dans des longueurs d'onde appropriées. Malheureusement, l'atmosphère terrestre qui nous sépare d'eux est aussi le siège de nombreuses émissions qui peuvent venir perturber les mesures. De toutes ces émissions, la principale est due au radical OH dont les raies de rotation-vibration couvrent tout le spectre entre 0,7 et 2,5 microns. Cette émission a lieu au niveau d'une couche assez fine de la haute atmosphère appelée mésopause et située à environ 85 kilomètres d'altitude. Le travail effectué a eu pour but de mettre en évidence les principales caractéristiques de cette émission qui n'est pas uniforme et constante dans le temps. Un programme d'observations dans le proche infrarouge a été élaboré. Plusieurs algorithmes de traitement d'image ont été développés. Un programme d'inversion de perspective a été mis au point pour une utilisation en temps réel sur le terrain. Les caractéristiques des images peuvent être ensuite analysées. La première partie du mémoire comporte une description des différentes émissions lumineuses que l'on peut observer la nuit lorsque l'on regarde la voûte céleste. Ces émissions peuvent avoir deux origines: astronomique ou atmosphérique. Le problème de l'absorption atmosphérique et plus précisément les conditions

A three-gene expression signature model for risk stratification of patients with neuroblastoma.

PubMed

Garcia, Idoia; Mayol, Gemma; Ríos, José; Domenech, Gema; Cheung, Nai-Kong V; Oberthuer, André; Fischer, Matthias; Maris, John M; Brodeur, Garrett M; Hero, Barbara; Rodríguez, Eva; Suñol, Mariona; Galvan, Patricia; de Torres, Carmen; Mora, Jaume; Lavarino, Cinzia

2012-04-01

Neuroblastoma is an embryonal tumor with contrasting clinical courses. Despite elaborate stratification strategies, precise clinical risk assessment still remains a challenge. The purpose of this study was to develop a PCR-based predictor model to improve clinical risk assessment of patients with neuroblastoma. The model was developed using real-time PCR gene expression data from 96 samples and tested on separate expression data sets obtained from real-time PCR and microarray studies comprising 362 patients. On the basis of our prior study of differentially expressed genes in favorable and unfavorable neuroblastoma subgroups, we identified three genes, CHD5, PAFAH1B1, and NME1, strongly associated with patient outcome. The expression pattern of these genes was used to develop a PCR-based single-score predictor model. The model discriminated patients into two groups with significantly different clinical outcome [set 1: 5-year overall survival (OS): 0.93 ± 0.03 vs. 0.53 ± 0.06, 5-year event-free survival (EFS): 0.85 ± 0.04 vs. 0.042 ± 0.06, both P < 0.001; set 2 OS: 0.97 ± 0.02 vs. 0.61 ± 0.1, P = 0.005, EFS: 0.91 ± 0.8 vs. 0.56 ± 0.1, P = 0.005; and set 3 OS: 0.99 ± 0.01 vs. 0.56 ± 0.06, EFS: 0.96 ± 0.02 vs. 0.43 ± 0.05, both P < 0.001]. Multivariate analysis showed that the model was an independent marker for survival (P < 0.001, for all). In comparison with accepted risk stratification systems, the model robustly classified patients in the total cohort and in different clinically relevant risk subgroups. We propose for the first time in neuroblastoma, a technically simple PCR-based predictor model that could help refine current risk stratification systems. ©2012 AACR.

A Three-Gene Expression Signature Model for Risk Stratification of Patients with Neuroblastoma

PubMed Central

Garcia, Idoia; Mayol, Gemma; Ríos, José; Domenech, Gema; Cheung, Nai-Kong V.; Oberthuer, André; Fischer, Matthias; Maris, John M.; Brodeur, Garrett M.; Hero, Barbara; Rodríguez, Eva; Suñol, Mariona; Galvan, Patricia; de Torres, Carmen; Mora, Jaume; Lavarino, Cinzia

2014-01-01

Purpose Neuroblastoma is an embryonal tumor with contrasting clinical courses. Despite elaborate stratification strategies, precise clinical risk assessment still remains a challenge. The purpose of this study was to develop a PCR-based predictor model to improve clinical risk assessment of patients with neuroblastoma. Experimental Design The model was developed using real-time PCR gene expression data from 96 samples and tested on separate expression data sets obtained from real-time PCR and microarray studies comprising 362 patients. Results On the basis of our prior study of differentially expressed genes in favorable and unfavorable neuroblastoma subgroups, we identified three genes, CHD5, PAFAH1B1, and NME1, strongly associated with patient outcome. The expression pattern of these genes was used to develop a PCR-based single-score predictor model. The model discriminated patients into two groups with significantly different clinical outcome [set 1: 5-year overall survival (OS): 0.93 ± 0.03 vs. 0.53 ± 0.06, 5-year event-free survival (EFS): 0.85 ± 0.04 vs. 0.042 ± 0.06, both P < 0.001; set 2 OS: 0.97 ± 0.02 vs. 0.61 ± 0.1, P = 0.005, EFS: 0.91 ± 0.8 vs. 0.56 ± 0.1, P = 0.005; and set 3 OS: 0.99 ± 0.01 vs. 0.56 ± 0.06, EFS: 0.96 ± 0.02 vs. 0.43 ± 0.05, both P < 0.001]. Multivariate analysis showed that the model was an independent marker for survival (P < 0.001, for all). In comparison with accepted risk stratification systems, the model robustly classified patients in the total cohort and in different clinically relevant risk subgroups. Conclusion We propose for the first time in neuroblastoma, a technically simple PCR-based predictor model that could help refine current risk stratification systems. PMID:22328561

Forest/Nonforest Classification of Landsat TM Data For Annual Inventory Phase One Stratification

Treesearch

Jim Rack

2001-01-01

Launch of Landsat 7 creates the opportunity to use relatively inexpensive and regularly acquired land cover data as an alternative to high altitude aerial photography. Creating a forest/nonforest mask from satellite imagery may offer a cost-effective alternative to interpretation of aerial photography for Phase One stratification of annual inventory plots. This paper...

Using classified Landsat Thematic Mapper data for stratification in a statewide forest inventory

Treesearch

Mark H. Hansen; Daniel G. Wendt

2000-01-01

The 1998 Indiana/Illinois forest inventory (USDA Forest Service, Forest Inventory and Analysis (FIA)) used Landsat Thematic Mapper (TM) data for stratification. Classified images made by the National Gap Analysis Program (GAP) stratified FIA plots into four classes (nonforest, nonforest/ forest, forest/nonforest, and forest) based on a two pixel forest edge buffer zone...

Using Classified Landsat Thematic Mapper Data for Stratification in a Statewide Forest Inventory

Treesearch

Mark H. Hansen; Daniel G. Wendt

2000-01-01

The 1998 Indiana/Illinois forest inventory (USDA Forest Service, Forest Inventory and Analysis (FIA)) used Landsat Thematic Mapper (TM} data for stratification. Classified images made by the National Gap Analysis Program (GAP) stratified FIA plots into four classes (nonforest, nonforest/forest, forest/nonforest, and forest) based on a two pixel forest edge buffer zone...

L’annonce d’une déficience motrice cérébrale : Une relation de confiance à construire entre les parents, le personnel paramédical et les médecins

PubMed Central

Pelchat, Diane; Lefebvre, Hélène; Bouchard, Jean-Marie

2001-01-01

RÉSUMÉ : L’annonce d’une déficience motrice cérébrale et des incapacités qui en découlent est une situation difficile à vivre pour les parents et les dispensateurs de soins (personnel paramédical et médecins). Un examen de la documentation médicale démontre que depuis vingt ans, le nombre de parents insatisfaits n’a pas changé. L’étude de type qualitatif et exploratoire, effectuée à la demande de milieux de réadaptation, vise à décrire le processus d’annonce d’un diagnostic de déficience motrice cérébrale (DMC) à partir de l’expérience des différents acteurs en cause et à déterminer les facteurs qui facilitent ou compliquent la relation de confiance. Les résultats indiquent que les parents et les dispensateurs de soins vivent dans deux mondes de perception différents au moment de l’annonce, lesquels se rejoignent difficilement. Les parents sont envahis par le drame qu’ils vivent, tandis que les médecins sont concentrés sur le contenu à transmettre aux parents. Cette annonce provoque une importante incertitude qui bloque la communication entre les partenaires, mais elle pourrait devenir un stimulant à de nouvelles stratégies d’adaptation. PMID:20084263

La pubalgie du sportif: mise au point à propos d'une étude rétrospective de 128 joueurs

PubMed Central

Mahmoudi, Ammar; Frioui, Samia; Jemni, Sonia; Khachnaoui, Faycel; Dahmene, Younes

2015-01-01

La pubalgie du sportif de haut niveau représente une entité nosologique à part entière, tant en raison du mécanisme à l'origine de la pathologie que des lésions objectivables au niveau de la paroi abdominale. C'est un syndrome douloureux de la région inguino-pubienne qui touche particulièrement les footballeurs. Son étiologie est attribuée à la répétition de mouvements des membres inférieurs et du tronc associant rotation et adduction forcées. Son incidence est nettement plus élevée chez les hommes. Après avoir écarté une pathologie d'organe, le patient devrait bénéficier tout au début de son traitement conservateur d'une IRM afin d'effectuer un bilan lésionnel complet qui, selon les situations, permet d’écourter le traitement conservateur et de proposer un traitement chirurgical optimal. Le traitement doit être résolument conservateur pendant 3 mois. La rééducation est le plus souvent le traitement de première intention. Les patients présentant une persistance des symptômes sont candidats à la chirurgie. L'intervention de Nesovic est le traitement de choix chez les sportifs de haut niveau et qui permet, dans la très grande majorité des cas, une reprise sans aucune limitation de l'activité sportive antérieure. La technique de Bassini semble être moins lourde que celle de Nesovic, puisqu'elle est moins invasive. Une prise en charge multidisciplinaire centrée sur l'athlète avant et après l'intervention permet un retour aux activités physiques après quelques mois. Nous rapportons l'expérience de la prise en charge de 128 joueurs opérés selon la technique de Bassini et nous comparons nos résultats avec celles de la littérature. PMID:26966484

Developpement d'une methode calorimetrique de mesure des pertes ac pour des rubans supraconducteurs a haute temperature critique

NASA Astrophysics Data System (ADS)

Dolez, Patricia

Le travail de recherche effectue dans le cadre de ce projet de doctorat a permis la mise au point d'une methode de mesure des pertes ac destinee a l'etude des supraconducteurs a haute temperature critique. Pour le choix des principes de cette methode, nous nous sommes inspires de travaux anterieurs realises sur les supraconducteurs conventionnels, afin de proposer une alternative a la technique electrique, presentant lors du debut de cette these des problemes lies a la variation du resultat des mesures selon la position des contacts de tension sur la surface de l'echantillon, et de pouvoir mesurer les pertes ac dans des conditions simulant la realite des futures applications industrielles des rubans supraconducteurs: en particulier, cette methode utilise la technique calorimetrique, associee a une calibration simultanee et in situ. La validite de la methode a ete verifiee de maniere theorique et experimentale: d'une part, des mesures ont ete realisees sur des echantillons de Bi-2223 recouverts d'argent ou d'alliage d'argent-or et comparees avec les predictions theoriques donnees par Norris, nous indiquant la nature majoritairement hysteretique des pertes ac dans nos echantillons; d'autre part, une mesure electrique a ete realisee in situ dont les resultats correspondent parfaitement a ceux donnes par notre methode calorimetrique. Par ailleurs, nous avons compare la dependance en courant et en frequence des pertes ac d'un echantillon avant et apres qu'il ait ete endommage. Ces mesures semblent indiquer une relation entre la valeur du coefficient de la loi de puissance modelisant la dependance des pertes avec le courant, et les inhomogeneites longitudinales du courant critique induites par l'endommagement. De plus, la variation en frequence montre qu'au niveau des grosses fractures transverses creees par l'endommagement dans le coeur supraconducteur, le courant se partage localement de maniere a peu pres equivalente entre les quelques grains de matiere

Direct numerical simulation of turbulent plane Couette flow under neutral and stable stratification

NASA Astrophysics Data System (ADS)

Mortikov, Evgeny

2017-11-01

Direct numerical simulation (DNS) approach was used to study turbulence dynamics in plane Couette flow under conditions ranging from neutral stability to the case of extreme stable stratification, where intermittency is observed. Simulations were performed for Reynolds numbers, based on the channel height and relative wall speed, up to 2 ×105 . Using DNS data, which covers a wide range of stability conditions, parameterizations of pressure correlation terms used in second-order closure turbulence models are discussed. Particular attention is also paid to the sustainment of intermittent turbulence under strong stratification. Intermittent regime is found to be associated with the formation of secondary large-scale structures elongated in the spanwise direction, which define spatially confined alternating regions of laminar and turbulent flow. The spanwise length of this structures increases with the increase in the bulk Richardson number and defines and additional constraint on the computational box size. In this work DNS results are presented in extended computational domains, where the intermittent turbulence is sustained for sufficiently higher Richardson numbers than previously reported.

Stratification, Elaboration and Formalisation of Design Documents: Effects on the Production of Instructional Materials

ERIC Educational Resources Information Center

Boot, Eddy W.; Nelson, Jon; van Merrienboer, Jeroen J. G.; Gibbons, Andrew S.

2007-01-01

Designers and producers of instructional materials lack a common design language. As a result, producers have difficulties translating design documents into technical specifications. The 3D-model is introduced to improve the stratification, elaboration and formalisation of design documents. It is hypothesised that producers working with improved…

The effect of thermal stratification on microbial community diversity and structure in a temperate reservoir

NASA Astrophysics Data System (ADS)

Qu, Jiangqi; Jia, Chengxia; Zhao, Meng; Li, Wentong; Liu, Pan; Yang, Mu; Zhang, Qingjing

2018-02-01

Miyun reservoir is a typical temperate deep reservoir located in the northeast of Beijing, China. In order to explore the effect of thermal stratification on microbial community diversity, structure and its influencing environmental factors, stratified sampling at three sites was conducted during the summer period. Field observations indicate that the water temperature and dissolved oxygen concentrations dropped to 11.9 °C and 1.57 mg/L, respectively, leading to the development of anoxia in the hypolimnetic layer. The Illumina Miseq sequencing results showed that microbial communities from different thermal stratification showed obvious differences, the highest microbial diversity and richness in the hypolimnion samples. RDA ordination analysis suggested that the microbial communities in the epilimnion and metalimnion were mainly affected by water temperature, pH and dissolved oxygen, while total nitrogen was the key environmental factor which shaped the microbial structure in hypolimnion.

Role of Southern Ocean stratification in glacial atmospheric CO2 reduction

NASA Astrophysics Data System (ADS)

Kobayashi, H.; Oka, A.

2014-12-01

Paleoclimate proxy data at the glacial period shows high salinity of more than 37.0 psu in the deep South Atlantic. At the same time, data also indicate that the residence time of the water mass was more than 3000 years. These data implies that the stratification by salinity was stronger in the deep Southern Ocean (SO) in the Last Glacial Maximum (LGM). Previous studies using Ocean General Circulation Model (OGCM) fail to explain the low glacial atmospheric carbon dioxide (CO2) concentration at LGM. The reproducibility of salinity and water mass age is considered insufficient in these OGCMs, which may in turn affect the reproducibility of the atmospheric CO2concentration. In coarse-resolution OGCMs, The deep water is formed by unrealistic open-ocean deep convection in the SO. Considering these facts, we guessed previous studies using OGCM underestimated the salinity and water mass age at LGM. This study investigate the role of the enhanced stratification in the glacial SO on the variation of atmospheric CO2 concentration by using OGCM. In order to reproduce the recorded salinity of the deep water, relaxation of salinity toward value of recorded data is introduced in our OGCM simulations. It was found that deep water formation in East Antarctica is required for explaining the high salinity in the South Atlantic. In contrast, it is difficult to explain the glacial water mass age, even if we assume the situation vertical mixing is very weak in the SO. Contrary to previous estimate, the high salinity of the deep SO resulted in increase of Antarctic Bottom water (AABW) flow and decrease the residence time of carbon in the deep ocean, which increased atmospheric CO2 concentration. On the other hand, the weakening of the vertical mixing in the SO contributed to increase the vertical gradient of dissolved inorganic carbon (DIC), which decreased atmospheric CO2 concentration. Adding the contribution of the enhanced stratification in the glacial SO, we obtained larger

Germination of Sweetgum in Response to Temherature, Moisture Stress, and Length of Stratification

Treesearch

F. T. Bonner; R. E. Farmer

1966-01-01

Both total germination and rate of germination of sweetgum seed increased as temperatures were raised from 60-75 to 85-100°F. Increases in osmotic stress lessened total germination and rate of germination, and 15 atmospheres of stress completely inhibited germination. Raising the temperatures decreased the influence of osmotic stress, and lengthening the stratification...

Drought tolerance associated with vertical stratification of two co-occurring epiphytic bromeliads in a tropical dry forest.

PubMed

Graham, Eric A; Andrade, Jose Luis

2004-05-01

Vertical stratification of epiphytes generally has not been reported for dry forests. For two epiphytic Crassulacean acid metabolism bromeliads that segregate vertically, it was hypothesized that different potentials for photoprotection or shade tolerance rather than drought tolerance is responsible for the observed stratification. The light environment, capacity for photoprotection, germination response to light quality, and responses to light and drought were thus examined for Tillandsia brachycaulos and T. elongata. Vertical and light-environment distributions differed for the two species but photoprotection and photodamage did not where they occurred at similar field locations; T. brachycaulos had a higher pigment acclimation to light. Tillandsia brachycaulos had higher acid accumulation under low light as opposed to T. elongata, which responded similarly to all but the highest light treatment. Tillandsia brachycaulos maintained positive total daily net CO(2) uptake through 30 d of drought; T. elongata had a total daily net CO(2) loss after 7 d of drought. The vertical stratification was most likely the result of the sensitivity to drought of T. elongata rather than differences in photoprotection or shade tolerance between the two species. Tillandsia elongata occurs in more exposed locations, which may be advantageous for rainfall interception and dew formation.

Numerical modeling of flows and pollutant dispersion within and above urban street canyons under unstable thermal stratification by large-eddy simulation

NASA Astrophysics Data System (ADS)

Chan, Ming-Chung; Liu, Chun-Ho

2013-04-01

Recently, with the ever increasing urban areas in developing countries, the problem of air pollution due to vehicular exhaust arouses the concern of different groups of people. Understanding how different factors, such as urban morphology, meteorological conditions and human activities, affect the characteristics of street canyon ventilation, pollutant dispersion above urban areas and pollutant re-entrainment from the shear layer can help us improve air pollution control strategies. Among the factors mentioned above, thermal stratification is a significant one determining the pollutant transport behaviors in certain situation, e.g. when the urban surface is heated by strong solar radiation, which, however, is still not widely explored. The objective of this study is to gain an in-depth understanding of the effects of unstable thermal stratification on the flows and pollutant dispersion within and above urban street canyons through numerical modeling using large-eddy simulation (LES). In this study, LES equipped with one-equation subgrid-scale (SGS) model is employed to model the flows and pollutant dispersion within and above two-dimensional (2D) urban street canyons (flanked by idealized buildings, which are square solid bars in these models) under different intensities of unstable thermal stratifications. Three building-height-to-street-width (aspect) ratios, 0.5, 1 and 2, are included in this study as a representation of different building densities. The prevailing wind flow above the urban canopy is driven by background pressure gradient, which is perpendicular to the street axis, while the condition of unstable thermal stratification is induced by applying a higher uniform temperature on the no-slip urban surface. The relative importance between stratification and background wind is characterized by the Richardson number, with zero value as a neutral case and negative value as an unstable case. The buoyancy force is modeled by Boussinesq approximation and the

Social stratification, classroom climate, and the behavioral adaptation of kindergarten children

PubMed Central

Boyce, W. Thomas; Obradović, Jelena; Bush, Nicole R.; Stamperdahl, Juliet; Kim, Young Shin; Adler, Nancy

2012-01-01

Socioeconomic status (SES) is the single most potent determinant of health within human populations, from infancy through old age. Although the social stratification of health is nearly universal, there is persistent uncertainty regarding the dimensions of SES that effect such inequalities and thus little clarity about the principles of intervention by which inequalities might be abated. Guided by animal models of hierarchical organization and the health correlates of subordination, this prospective study examined the partitioning of children's adaptive behavioral development by their positions within kindergarten classroom hierarchies. A sample of 338 5-y-old children was recruited from 29 Berkeley, California public school classrooms. A naturalistic observational measure of social position, parent-reported family SES, and child-reported classroom climate were used in estimating multilevel, random-effects models of children's adaptive behavior at the end of the kindergarten year. Children occupying subordinate positions had significantly more maladaptive behavioral outcomes than their dominant peers. Further, interaction terms revealed that low family SES and female sex magnified, and teachers’ child-centered pedagogical practices diminished, the adverse influences of social subordination. Taken together, results suggest that, even within early childhood groups, social stratification is associated with a partitioning of adaptive behavioral outcomes and that the character of larger societal and school structures in which such groups are nested can moderate rank–behavior associations. PMID:23045637

Social stratification, classroom climate, and the behavioral adaptation of kindergarten children.

PubMed

Boyce, W Thomas; Obradovic, Jelena; Bush, Nicole R; Stamperdahl, Juliet; Kim, Young Shin; Adler, Nancy

2012-10-16

Socioeconomic status (SES) is the single most potent determinant of health within human populations, from infancy through old age. Although the social stratification of health is nearly universal, there is persistent uncertainty regarding the dimensions of SES that effect such inequalities and thus little clarity about the principles of intervention by which inequalities might be abated. Guided by animal models of hierarchical organization and the health correlates of subordination, this prospective study examined the partitioning of children's adaptive behavioral development by their positions within kindergarten classroom hierarchies. A sample of 338 5-y-old children was recruited from 29 Berkeley, California public school classrooms. A naturalistic observational measure of social position, parent-reported family SES, and child-reported classroom climate were used in estimating multilevel, random-effects models of children's adaptive behavior at the end of the kindergarten year. Children occupying subordinate positions had significantly more maladaptive behavioral outcomes than their dominant peers. Further, interaction terms revealed that low family SES and female sex magnified, and teachers' child-centered pedagogical practices diminished, the adverse influences of social subordination. Taken together, results suggest that, even within early childhood groups, social stratification is associated with a partitioning of adaptive behavioral outcomes and that the character of larger societal and school structures in which such groups are nested can moderate rank-behavior associations.

High efficiency stratification of apple cultivar Ligol seed dormancy by phytohormones, heat shock and pulsed radio frequency.

PubMed

Grzesik, Mieczysław; Górnik, Krzysztof; Janas, Regina; Lewandowki, Mariusz; Romanowska-Duda, Zdzislawa; Duijn, Bert van

2017-12-01

The aim of the study was to improve the effect of stratification of apple "Ligol" seeds by application of selected compounds, phytohormones, and physical methods For this purpose the seeds were stratified at 3°C in distilled water or in the presence of potassium nitrate (KNO 3 ), ethephon (ET), carbon monoxide (CO), hydrogen peroxide (H 2 O 2 ), a mixture of KNO 3 , ET, CO, H 2 O 2 , gibberellins (GA 3 ), 6-benzylaminopurine (BAP), jasmonic acid (JA), salicylic acid (SA) and a mixture of SA, GA 3 , BAP, JA, nitric oxide (NO), hydrogen chloride (HCL). Arranged protocols included various durations and combinations of selected compounds and phytohormones as well as laser and red light, heat shock - 2h heat shock (45°C) and Pulsed Radio Frequency (PRF) were investigated by germination tests and the activity of selected enzymes, gas exchange and index of chlorophyll in leaves. The obtained results showed the possibility to shorten more effectively the time of the apple 'Ligol' dormancy removal by treatments of the stratified seeds at 3°C with different biological and physical methods Selected compounds and phytohormones acted collectively as a regulatory complex controlling the course of release from dormancy. Physical methods (PRF and heat shock) additionally contributed to dormancy breakage. Duration of phytohormones or compounds impacts during stratification should be prolonged to minimum 7days to assure more balanced conditions of the regulatory complex for the acceleration of dormancy a removal. The most beneficial results were obtained after seed stratification for 7days on filter paper moistened in KNO 3 +Etephon+CO+H 2 O 2 at 3°C, and then on filter paper moistened in phytohormones (GA 3 +BAP+JA) till the end of seed germination (3°C). The application of this protocol could be a very useful tool in a shortening the apple breeding cycle since the period of removing dormancy was reduced by 38days in comparison to stratified in water. PRF has also the additive

Risk stratification in secondary cardiovascular prevention.

PubMed

Lazzeroni, Davide; Coruzzi, Paolo

2018-02-19

Worldwide, more than 7 million people experience acute myocardial infarction (AMI) every year (1), and although substantial reduction in mortality has been obtained in recent decades, one-year mortality rates are still in the range of 10%. Among patients who survive AMI, 20% suffer a second cardiovascular event in the first year and approximately 50% of major coronary events occur in those with a previous hospital discharge diagnosis of AMI (2). Despite the evidence that lifestyle changes and risk factors management strongly improve long-term prognosis, preventive care post-AMI remains sub-optimal. Cross-sectional data from the serially conducted EUROASPIRE surveys in patients with established ischemic heart disease (IHD) and people at high cardiovascular risk have demonstrated a high prevalence of unhealthy lifestyle, modifiable risk factors and inadequate use of drug therapies to achieve blood pressure and lipid goals (3). Secondary prevention programmes, defined as the level of preventive care focusing on early risk stratification, are highly recommended in all IHD patients, to restore quality of life, maintain or improve functional capacity and prevent recurrence.

Syncope: risk stratification and clinical decision making.

PubMed

Peeters, Suzanne Y G; Hoek, Amber E; Mollink, Susan M; Huff, J Stephen

2014-04-01

Syncope is a common occurrence in the emergency department, accounting for approximately 1% to 3% of presentations. Syncope is best defined as a brief loss of consciousness and postural tone followed by spontaneous and complete recovery. The spectrum of etiologies ranges from benign to life threatening, and a structured approach to evaluating these patients is key to providing care that is thorough, yet cost-effective. This issue reviews the most relevant evidence for managing and risk stratifying the syncope patient, beginning with a focused history, physical examination, electrocardiogram, and tailored diagnostic testing. Several risk stratification decision rules are compared for performance in various scenarios, including how age and associated comorbidities may predict short-term and long-term adverse events. An algorithm for structured, evidence-based care of the syncope patient is included to ensure that patients requiring hospitalization are managed appropriately and those with benign causes are discharged safely.

Hématome sous capsulaire de foie compliquant une pré-éclampsie: à propos de 6 cas

PubMed Central

Mamouni, Nisrine; Derkaoui, Ali; Bougern, Hakima; Bouchikhi, Chehrazad; Chaara, Hikmat; Banani, Abdelaziz; Abdelilah, Melhouf Moulay

2011-01-01

L'hématome sous capsulaire du foie (HSCF) est une complication rare mais gravissime de la grossesse. Devant une symptomatologie clinique souvent non spécifique et un tableau biologique retardé, son diagnostic est basé essentiellement sur les moyens de l'imagerie (échographie, TDM, IRM). Son traitement est fonction de l'intégrité ou non de la capsule de Glisson. Nous rapportons les observations de 6 patientes, à travers une étude rétrospective s’étalant sur la période du Janvier 2005 à Octobre 2008, incluant tous les cas de preeclampsie colligés au service de gynécologie obstétrique du CHU Hassan II. Durant la période d’étude, L'incidence de l'hématome sous capsulaire de foie chez les patientes préeclamptiques admises durant la période d’étude est de 1,49 %. Aucune des patientes n'a benificié d'un suivi prénatal au sein de notre formation. La moyenne d’âge des patientes est de 37,6 ans avec des extrêmes allant de 33 à 45 ans. La gestité moyenne était de 4,8 avec une parité moyenne de 4,5.l'hematome sous capsulaire est survenu en post partum chez tous nos cas avec un délai moyen de 4 jours et des extrêmes allant de J0 et J10 du post partum .Toutes les patientes ont présenté un HELLP syndrome concomitant à la survenue de cette complication gravissime.Le diagnostic positif s'est basé sur les données échographiques dans 5 cas (hemoperitoine –HSCF).l’équipe a opté pour une abstention thérapeutique avec surveillance armée chez 2 cas et l'exploration chirurgicale a été indiquée chez quatre patientes en instabilité hemodynamique.Nous avons déploré deux cas de décès maternel. PMID:22145072

Unification of favourable intermediate-, unfavourable intermediate-, and very high-risk stratification criteria for prostate cancer.

PubMed

Zumsteg, Zachary S; Zelefsky, Michael J; Woo, Kaitlin M; Spratt, Daniel E; Kollmeier, Marisa A; McBride, Sean; Pei, Xin; Sandler, Howard M; Zhang, Zhigang

2017-11-01

To improve on the existing risk-stratification systems for prostate cancer. This was a retrospective investigation including 2 248 patients undergoing dose-escalated external beam radiotherapy (EBRT) at a single institution. We separated National Comprehensive Cancer Network (NCCN) intermediate-risk prostate cancer into 'favourable' and 'unfavourable' groups based on primary Gleason pattern, percentage of positive biopsy cores (PPBC), and number of NCCN intermediate-risk factors. Similarly, NCCN high-risk prostate cancer was stratified into 'standard' and 'very high-risk' groups based on primary Gleason pattern, PPBC, number of NCCN high-risk factors, and stage T3b-T4 disease. Patients with unfavourable-intermediate-risk (UIR) prostate cancer had significantly inferior prostate-specific antigen relapse-free survival (PSA-RFS, P < 0.001), distant metastasis-free survival (DMFS, P < 0.001), prostate cancer-specific mortality (PCSM, P < 0.001), and overall survival (OS, P < 0.001) compared with patients with favourable-intermediate-risk (FIR) prostate cancer. Similarly, patients with very high-risk (VHR) prostate cancer had significantly worse PSA-RFS (P < 0.001), DMFS (P < 0.001), and PCSM (P = 0.001) compared with patients with standard high-risk (SHR) prostate cancer. Moreover, patients with FIR and low-risk prostate cancer had similar outcomes, as did patients with UIR and SHR prostate cancer. Consequently, we propose the following risk-stratification system: Group 1, low risk and FIR; Group 2, UIR and SHR; and Group 3, VHR. These groups have markedly different outcomes, with 8-year distant metastasis rates of 3%, 9%, and 29% (P < 0.001) for Groups 1, 2, and 3, respectively, and 8-year PCSM of 1%, 4%, and 13% (P < 0.001) after EBRT. This modified stratification system was significantly more accurate than the three-tiered NCCN system currently in clinical use for all outcomes. Modifying the NCCN risk-stratification system to group FIR with low-risk patients and UIR

Stratification Pattern of Static and Scale-Invariant Dynamic Measures of Heartbeat Fluctuations Across Sleep Stages in Young and Elderly

PubMed Central

Schmitt, Daniel T.; Stein, Phyllis K.; Ivanov, Plamen Ch.

2010-01-01

Cardiac dynamics exhibit complex variability characterized by scale-invariant and nonlinear temporal organization related to the mechanism of neuroautonomic control, which changes with physiologic states and pathologic conditions. Changes in sleep regulation during sleep stages are also related to fluctuations in autonomic nervous activity. However, the interaction between sleep regulation and cardiac autonomic control remains not well understood. Even less is known how this interaction changes with age, as aspects of both cardiac dynamics and sleep regulation differ in healthy elderly compared to young subjects. We hypothesize that because of the neuroautonomic responsiveness in young subjects, fractal and nonlinear features of cardiac dynamics exhibit a pronounced stratification pattern across sleep stages, while in elderly these features will remain unchanged due to age-related loss of cardiac variability and decline of neuroautonomic responsiveness. We analyze the variability and the temporal fractal organization of heartbeat fluctuations across sleep stages in both young and elderly. We find that independent linear and nonlinear measures of cardiac control consistently exhibit the same ordering in their values across sleep stages, forming a robust stratification pattern. Despite changes in sleep architecture and reduced heart rate variability in elderly subjects, this stratification surprisingly does not break down with advanced age. Moreover, the difference between sleep stages for some linear, fractal, and nonlinear measures exceeds the difference between young and elderly, suggesting that the effect of sleep regulation on cardiac dynamics is significantly stronger than the effect of healthy aging. Quantifying changes in this stratification pattern may provide insights into how alterations in sleep regulation contribute to increased cardiac risk. PMID:19203874

La syphilis congénitale révélée par une fracture spontanée

PubMed Central

Idrissi, Mounia Lakhdar; Ismaili, Leila; Bouharrou, Abdelhak; Hida, Moustapha

2011-01-01

Alors qu'elle est actuellement oubliée dans les pays développés, la syphilis congénitale se voit encore chez nous faute du dépistage anténatal. Ses formes cliniques sont polymorphes et orientent à tord vers d'autres pathologies surtout en période néonatale. Le diagnostic n'est donc pas toujours facile. La révélation d'une syphilis congénitale par une fracture spontanée est exceptionnellement décrite. Nous rapportons dans ce travail le cas d'un nourrisson de 2 mois ramené en consultation pour limitation douloureuse des mouvements du bras droit. Le diagnostic est évoqué sur les données radiologiques et confirmé par la sérologie syphilitique. Le traitement a reposé essentiellement sur l'administration de la pénicilline G avec une bonne évolution clinique. PMID:22384288

Dissipation in the Baltic proper during winter stratification

NASA Astrophysics Data System (ADS)

Lass, Hans Ulrich; Prandke, Hartmut; Liljebladh, Bengt

2003-06-01

Profiles of dissipation rates and stratification between 10 and 120 m depth were measured with a loosely tethered profiler over a 9-day winter period in the Gotland Basin of the Baltic Sea. Supplementary measurements of current profiles were made with moored ADCPs. Temporal and spatial patterns of the stratification were observed by means of towed CTD. Shallow freshwater lenses in the surface mixed layer, mesoscale eddies, inertial oscillations, and inertial waves as part of the internal wave spectrum provided the marine physical environment for the small-scale turbulence. Two well-separated turbulence regimes were detected. The turbulence in the surface mixed layer was well correlated with the wind. The majority of the energy flux from the wind to the turbulent kinetic energy was dissipated within the surface mixed layer. A minor part of this flux was consumed by changes of the potential energy of the fresh water lenses. The penetration depth Hpen of the wind-driven turbulence into the weakly stratified surface mixed layer depended on the local wind speed (W10) as Hpen = cW103/2 Active erosion of the Baltic halocline by wind-driven turbulence is expected for wind speeds greater than 14 m/s. The turbulence in the strongly stratified interior of the water column was quite independent of the meteorological forcing at the sea surface. The integrated production of turbulent kinetic energy exceeded the energy loss of inertial oscillations in the surface layer suggesting additional energy sources which might have been provided by inertial wave radiation during geostrophic adjustment of coastal jets and mesoscale eddies. The averaged dissipation rate profile in the stratified part of the water column, best fitted by ɛ ∝ EN, was different from the scaling of the dissipation in the thermocline of the ocean [, 1986]. The diapycnical mixing coefficient (Kv) was best fit by Kv = a0/N according to [1987] with a0 ≈ 0.87 × 10-7 m2/s2. The diapycnal diffusivity estimated

Improved fluid dynamics similarity, analysis and verification. Part 5: Analytical and experimental studies of thermal stratification phenomena

NASA Technical Reports Server (NTRS)

Winter, E. R. F.; Schoenhals, R. J.; Haug, R. I.; Libby, T. L.; Nelson, R. N.; Stevenson, W. H.

1968-01-01

The stratification behavior of a contained fluid subjected to transient free convection heat transfer was studied. A rectangular vessel was employed with heat transfer from two opposite walls of the vessel to the fluid. The wall temperature was increased suddenly to initiate the process and was then maintained constant throughout the transient stratification period. Thermocouples were positioned on a post at the center of the vessel. They were adjusted so that temperatures could be measured at the fluid surface and at specific depths beneath the surface. The predicted values of the surface temperature and the stratified layer thickness were found to agree reasonably well with the experimental measurements. The experiments also provided information on the transient centerline temperature distribution and the transient flow distribution.

Cascading in Higher Education: Investigating the Impact of Institutional Stratification on Educational Opportunity in America

ERIC Educational Resources Information Center

Bastedo, Michael N.; Jaquette, Ozan; Harris, Nathan F.

2009-01-01

Among scholars of social stratification, the most important question about expanding postsecondary education is whether it reduces inequality by creating opportunities for disadvantaged students or whether it increases inequality by concentrating opportunities among those already privileged (Shavit, 2007). This discussion is important because of…

Shaped Goals: Teaching Undergraduates the Effects of Social Stratification on the Formulation of Goals

ERIC Educational Resources Information Center

Touzard, Giselle

2009-01-01

This article describes an in-class activity that helps undergraduate students to understand the effects of their socio-economic position on the formulation, pursuit, and achievement of goals. Social stratification and inequality have an initial impact on the formulation of goals. Through this exercise students will perceive the effects of having a…

Clinical Risk Stratification for Primary Prevention Implantable Cardioverter Defibrillators

PubMed Central

Hardy, Judy; Yee, Raymond; Healey, Jeffrey S.; Birnie, David; Simpson, Christopher S.; Crystal, Eugene; Mangat, Iqwal; Nanthakumar, Kumaraswamy; Wang, Xuesong; Krahn, Andrew D.; Dorian, Paul; Austin, Peter C.; Tu, Jack V.

2015-01-01

Background— A conceptualized model may be useful for understanding risk stratification of primary prevention implantable cardioverter defibrillators considering the competing risks of appropriate implantable cardioverter defibrillator shock versus mortality. Methods and Results— In a prospective, multicenter, population-based cohort with left ventricular ejection fraction ≤35% referred for primary prevention implantable cardioverter defibrillator, we developed dual risk stratification models to determine the competing risks of appropriate defibrillator shock versus mortality using a Fine-Gray subdistribution hazard model. Among 7020 patients referred, 3445 underwent defibrillator implant (79.7% men, median, 66 years [25th, 75th: 58–73]). During 5918 person-years of follow-up, appropriate shock occurred in 204 patients (3.6 shocks/100 person-years) and 292 died (4.9 deaths/100 person-years). Competing risk predictors of appropriate shock included nonsustained ventricular tachycardia, atrial fibrillation, serum creatinine concentration, digoxin or amiodarone use, and QRS duration near 130-ms peak. One-year cumulative incidence of appropriate shock was 0.9% in the lowest risk category, and 1.7%, 2.5%, 4.9%, and 9.3% in low, intermediate, high, and highest risk groups, respectively. Hazard ratios for appropriate shock ranged from 4.04 to 7.79 in the highest 3 deciles (all P≤0.001 versus lowest risk). Cumulative incidence of 1-year death was 0.6%, 1.9%, 3.3%, 6.2%, and 17.7% in lowest, low, intermediate, high, and highest risk groups, respectively. Mortality hazard ratios ranged from 11.48 to 36.22 in the highest 3 deciles (all P<0.001 versus lowest risk). Conclusions— Simultaneous estimation of risks of appropriate shock and mortality can be performed using clinical variables, providing a potential framework for identification of patients who are unlikely to benefit from prophylactic implantable cardioverter defibrillator. PMID:26224792

Lambeau Expanse du Cuir Chevelu dans la Couverture des Alopecies Cicatricielles sur Sequelles de Brulures. A Propos d'une Observation

PubMed Central

El Mazouz, S.; Hafidi, J.; Fejjal, N.; Mejjati, H.; Cherkab, L.; Gharib, N.; Abbassi, A.

2010-01-01

Summary Les séquelles esthétiques des alopécies cicatricielles sur séquelles de brûlures sont responsables de préjudices empêchant parfois la réinsertion sociale du patient, surtout chez les sujets de sexe féminin. Le cuir chevelu permet la réalisation de lambeaux permettant de couvrir ces alopécies. Les Auteurs décrivent le cas d'une jeune patiente victime d'une alopécie cicatricielle sur séquelles de brûlures chez qui ils ont réalisé un lambeau expansé du cuir chevelu et mettent le point sur la prise en charge de ces lésions à travers ce cas clinique et une revue de littérature. PMID:21991195

Understanding the Effect of Stratification on Vertical and Temporal Heterogenieties of Cyanobacteria Blooms in Lakes Using a Long Term in-situ Monitoring Station

NASA Astrophysics Data System (ADS)

Wilkinson, A.; Guala, M.; Hondzo, M.

2017-12-01

Harmful Algal Blooms (HAB) are made up of potentially toxic freshwater microorganisms called cyanobacteria, because of this they are a ecological and public health hazard. The occurrences of toxic HAB are unpredictable and highly spatially and temporary variable in freshwater ecosystems. To study the abiotic drivers for toxic HAB, a floating research station has been deployed in a hyper-eutrophic lake in Madison Lake, Minnesota, from June-October 2016. This research station provides full depth water quality (hourly) and meteorological monitoring (5 minutes). Water quality monitoring is performed by an autonomously traversed water quality sonde that provides chemical, physical and biological measurements; including phycocyanin, a photosynthetic pigment distinct to cyanobacteria. A bloom of cyanobacteria recorded in the epiliminion in mid-July was driven by prolonged strong thermal stratification in the water column, high surface water temperatures and high phosphate concentrations in the epiliminion. The high biovolume (BV) persisted until late September and was sustained below the surface after stratification weakened, when the thermocline did not confine cyanobacteria-rich layers any more, and cyanobacteria vertical heterogeneities decayed in the water column. High correlations among BV stratification, surface water temperature, and stratification stability informed the development of a quantitative relationship to determine how BV heterogeneities vary with thermal structure in the water column. The BV heterogeneity decreased with thermal stratification stability and surface water temperature, and the dynamic lake stability described by the Lake Number. Finally the location of maximum BV accumulation showed diurnal patterns ie. BV peaks were observed at 1 m depth during the day and deeper layers during the night, which followed patterns in light penetration and thermocline depth. These findings capture cyanobacteria vertical and temporal heterogeneities on a on

[From symmetries to the laws of evolution. I. Chirality as a means of active media stratification].

PubMed

Tverdislov, V A; Sidorova, A É; Iakovenko, L V

2012-01-01

Features of the hypothetical evolution of a hierarchy of chiral objects formed by active media are discussed. On the basis of experimental facts a new synergetic generalization is made: an evolving system can repeatedly broaden the spectrum of its symmetry types within one level of organization which increases its complexity and change the sign of chirality during transition to a higher level. Switching the chirality sign of macroscopic objects provides irreversibility of stratification. The known chirality of biological structures at different levels suggests that the chiral L/D-stratification should be universal and the hierarchical paths are stable and determined. A high level enantiomorph with reciprocal chirality demonstrates a wider spectrum of functionality. A fractal description of natural hierarchical systems is pointed out to be inadequate because it implicates invariance of the chirality sign of the objects at different scales.

Plasma ion stratification by weak planar shocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simakov, Andrei N.; Keenan, Brett D.; Taitano, William T.

We derive fluid equations for describing steady-state planar shocks of a moderate strength (0 < M - 1 ≲ 1 with M the shock Mach number) propagating through an unmagnetized quasineutral collisional plasma comprising two separate ion species. In addition to the standard fluid shock quantities, such as the total mass density, mass-flow velocity, and electron and average ion temperatures, the equations describe shock stratification in terms of variations in the relative concentrations and temperatures of the two ion species along the shock propagation direction. We have solved these equations analytically for weak shocks (0 < M - 1 <

Plasma Ion Stratification by Weak Planar Shocks

NASA Astrophysics Data System (ADS)

Simakov, A. N.; Keenan, B. D.; Taitano, W. T.; Chacón, L.

2017-10-01

We derive fluid equations for describing steady-state planar shocks of a moderate strength (0stratification in terms of variations in the relative concentrations and temperatures of the two ion species along the shock propagation direction. We have solved these equations analytically for weak shocks (0

Plasma ion stratification by weak planar shocks

NASA Astrophysics Data System (ADS)

Simakov, Andrei N.; Keenan, Brett D.; Taitano, William T.; Chacón, Luis

2017-09-01

We derive fluid equations for describing steady-state planar shocks of a moderate strength ( 0 stratification in terms of variations in the relative concentrations and temperatures of the two ion species along the shock propagation direction. We have solved these equations analytically for weak shocks ( 0

Plasma ion stratification by weak planar shocks

DOE PAGES

Simakov, Andrei N.; Keenan, Brett D.; Taitano, William T.; ...

2017-08-01

We derive fluid equations for describing steady-state planar shocks of a moderate strength (0 < M - 1 ≲ 1 with M the shock Mach number) propagating through an unmagnetized quasineutral collisional plasma comprising two separate ion species. In addition to the standard fluid shock quantities, such as the total mass density, mass-flow velocity, and electron and average ion temperatures, the equations describe shock stratification in terms of variations in the relative concentrations and temperatures of the two ion species along the shock propagation direction. We have solved these equations analytically for weak shocks (0 < M - 1 <

Raynaud’s phenomenon and digital ischemia: a practical approach to risk stratification, diagnosis and management

PubMed Central

McMahan, Zsuzsanna H.; Wigley, Fredrick M.

2015-01-01

Digital ischemia is a painful and often disfiguring event. Such an ischemic event often leads to tissue loss and can significantly affect the patient’s quality of life. Digital ischemia can be secondary to a vasculopathy, vasculitis, embolic disease, trauma, or extrinsic vascular compression. It is an especially serious complication in patients with scleroderma. Risk stratification of patients with scleroderma at risk for digital ischemia is now possible with clinical assessment and autoantibody profiles. Because there are a variety of conditions that lead to digital ischemia, it is important to understand the pathophysiology underlying each ischemic presentation in order to target therapy appropriately. Significant progress has been made in the last two decades in defining the pathophysiological processes leading to digital ischemia in rheumatic diseases. In this article we review the risk stratification, diagnosis, and management of patients with digital ischemia and provide a practical approach to therapy, particularly in scleroderma. PMID:26523153

Enhanced subarctic Pacific stratification and nutrient utilization during glacials over the last 1.2 Myr

NASA Astrophysics Data System (ADS)

Knudson, Karla P.; Ravelo, Ana Christina

2015-11-01

The relationship between climate, biological productivity, and nutrient flux is of considerable interest in the subarctic Pacific, which represents an important high-nitrate, low-chlorophyll region. While previous studies suggest that changes in iron supply and/or physical ocean stratification could hypothetically explain orbital-scale fluctuations in subarctic Pacific nutrient utilization and productivity, previous records of nutrient utilization are too short to evaluate these relationships over many glacial-interglacial cycles. We present new, high-resolution records of sedimentary δ15N, which offer the first opportunity to evaluate systematic, orbital-scale variations in subarctic Pacific nitrate utilization from 1.2 Ma. Nitrate utilization was enhanced during all glacials, varied with orbital-scale periodicity since the mid-Pleistocene transition, was strongly correlated with enhanced aeolian dust and low atmospheric CO2, but was not correlated with productivity. These results suggest that glacial stratification, rather than iron fertilization, systematically exerted an important regional control on nutrient utilization and air-sea carbon flux.

LGN plays distinct roles in oral epithelial stratification, filiform papilla morphogenesis and hair follicle development

PubMed Central

Lough, Kendall J.; Patel, Jeet H.; Descovich, Carlos Patiño; Curtis, T. Anthony

2016-01-01

Oral epithelia protect against constant challenges by bacteria, viruses, toxins and injury while also contributing to the formation of ectodermal appendages such as teeth, salivary glands and lingual papillae. Despite increasing evidence that differentiation pathway genes are frequently mutated in oral cancers, comparatively little is known about the mechanisms that regulate normal oral epithelial development. Here, we characterize oral epithelial stratification and describe multiple distinct functions for the mitotic spindle orientation gene LGN (Gpsm2) in promoting differentiation and tissue patterning in the mouse oral cavity. Similar to its function in epidermis, apically localized LGN directs perpendicular divisions that promote stratification of the palatal, buccogingival and ventral tongue epithelia. Surprisingly, however, in dorsal tongue LGN is predominantly localized basally, circumferentially or bilaterally and promotes planar divisions. Loss of LGN disrupts the organization and morphogenesis of filiform papillae but appears to be dispensable for embryonic hair follicle development. Thus, LGN has crucial tissue-specific functions in patterning surface ectoderm and its appendages by controlling division orientation. PMID:27317810

Rain Impact Model Assessment of Near-Surface Salinity Stratification Following Rainfall

NASA Astrophysics Data System (ADS)

Drushka, K.; Jones, L.; Jacob, M. M.; Asher, W.; Santos-Garcia, A.

2016-12-01

Rainfall over oceans produces a layer of fresher surface water, which can have a significant effect on the exchanges between the surface and the bulk mixed layer and also on satellite/in-situ comparisons. For satellite sea surface salinity (SSS) measurements, the standard is the Hybrid Coordinate Ocean Model (HYCOM), but there is a significant difference between the remote sensing sampling depth of 0.01 m and the typical range of 5-10 m of in-situ instruments. Under normal conditions the upper layer of the ocean is well mixed and there is uniform salinity; however, under rainy conditions, there is a dilution of the near-surface salinity that mixes downward by diffusion and by mechanical mixing (gravity waves/wind speed). This significantly modifies the salinity gradient in the upper 1-2 m of the ocean, but these transient salinity stratifications dissipate in a few hours, and the upper layer becomes well mixed at a slightly fresher salinity. Based upon research conducted within the NASA/CONAE Aquarius/SAC-D mission, a rain impact model (RIM) was developed to estimate the change in SSS due to rainfall near the time of the satellite observation, with the objective to identify the probability of salinity stratification. RIM uses HYCOM (which does not include the short-term rain effects) and a NOAA global rainfall product CMORPH to model changes in the near-surface salinity profile in 0.5 h increments. Based upon SPURS-2 experimental near-surface salinity measurements with rain, this paper introduces a term in the RIM model that accounts for the effect of wind speed in the mechanical mixing, which translates into a dynamic vertical diffusivity; whereby a Generalized Ocean Turbulence Model (GOTM) is used to investigate the response to rain events of the upper few meters of the ocean. The objective is to determine how rain and wind forcing control the thickness, stratification strength, and lifetime of fresh lenses and to quantify the impacts of rain-formed fresh lenses

Influence of precipitating light elements on stable stratification below the core/mantle boundary

NASA Astrophysics Data System (ADS)

O'Rourke, J. G.; Stevenson, D. J.

2017-12-01

Stable stratification below the core/mantle boundary is often invoked to explain anomalously low seismic velocities in this region. Diffusion of light elements like oxygen or, more slowly, silicon could create a stabilizing chemical gradient in the outermost core. Heat flow less than that conducted along the adiabatic gradient may also produce thermal stratification. However, reconciling either origin with the apparent longevity (>3.45 billion years) of Earth's magnetic field remains difficult. Sub-isentropic heat flow would not drive a dynamo by thermal convection before the nucleation of the inner core, which likely occurred less than one billion years ago and did not instantly change the heat flow. Moreover, an oxygen-enriched layer below the core/mantle boundary—the source of thermal buoyancy—could establish double-diffusive convection where motion in the bulk fluid is suppressed below a slowly advancing interface. Here we present new models that explain both stable stratification and a long-lived dynamo by considering ongoing precipitation of magnesium oxide and/or silicon dioxide from the core. Lithophile elements may partition into iron alloys under extreme pressure and temperature during Earth's formation, especially after giant impacts. Modest core/mantle heat flow then drives compositional convection—regardless of thermal conductivity—since their solubility is strongly temperature-dependent. Our models begin with bulk abundances for the mantle and core determined by the redox conditions during accretion. We then track equilibration between the core and a primordial basal magma ocean followed by downward diffusion of light elements. Precipitation begins at a depth that is most sensitive to temperature and oxygen abundance and then creates feedbacks with the radial thermal and chemical profiles. Successful models feature a stable layer with low seismic velocity (which mandates multi-component evolution since a single light element typically

Mathematical and physical modeling of thermal stratification phenomena in steel ladles

NASA Astrophysics Data System (ADS)

Putan, V.; Vilceanu, L.; Socalici, A.; Putan, A.

2018-01-01

By means of CFD numerical modeling, a systematic analysis of the similarity between steel ladles and hot-water model regarding natural convection phenomena was studied. The key similarity criteria we found to be dependent on the dimensionless numbers Fr and βΔT. These similarity criteria suggested that hot-water models with scale in the range between 1/5 and 1/3 and using hot water with temperature of 45 °C or higher are appropriate for simulating natural convection in steel ladles. With this physical model, thermal stratification phenomena due to natural convection in steel ladles were investigated. By controlling the cooling intensity of water model to correspond to the heat loss rate of steel ladles, which is governed by Fr and βΔT, the temperature profiles measured in the water bath of the model were to deduce the extent of thermal stratification in liquid steel bath in the ladles. Comparisons between mathematically simulated temperature profiles in the prototype steel ladles and those physically simulated by scaling-up the measured temperatures profiles in the water model showed good agreement. This proved that it is feasible to use a 1/5 scale water model with 45 °C hot water to simulate natural convection in steel ladles. Therefore, besides mathematical CFD models, the physical hot-water model provided an additional means of studying fluid flow and heat transfer in steel ladles.

Fostering Success or Stratification? A Macroapproach to Understanding "Success" in the Community College Context

ERIC Educational Resources Information Center

Ireland, S. Mei-Yen

2015-01-01

The topic of student success is a central focus for community college educators and researchers, yet little consideration is given to the long-term success that community college students may or may not be attaining. What role (if any) do concerns about social stratification have in the debate over student success? Exploring the ways in which…

Investigation of Methods to Predict Thermal Stratification and Its Effect on Solar Energy System Performance.

DTIC Science & Technology

1980-05-01

International Conference, Vol 1, Dhahran, Saudi Arabia (November 1975), pp 508-510. + C. W. J. Van Koppen, L. S. Fischer, and A. Dijkmans ...S. Fischer, and A. Dijkmans , "Stratification Effects in te Short and Long Term Storage of Solar Heat," Proceed- ings, 1978 meeting of Amercan Sec

ICCS 2009 User Guide for the International Database. Supplement 4: ICCS 2009 Sampling Stratification Information

ERIC Educational Resources Information Center

Brese, Falk; Jung, Michael; Mirazchiyski, Plamen; Schulz, Wolfram; Zuehlke, Olaf

2011-01-01

This supplement contains documentation on the explicit and implicit stratification variables included in the International Civic and Citizenship Education Study (ICCS) 2009 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata…

A two-stage clinical decision support system for early recognition and stratification of patients with sepsis: an observational cohort study.

PubMed

Amland, Robert C; Lyons, Jason J; Greene, Tracy L; Haley, James M

2015-10-01

To examine the diagnostic accuracy of a two-stage clinical decision support system for early recognition and stratification of patients with sepsis. Observational cohort study employing a two-stage sepsis clinical decision support to recognise and stratify patients with sepsis. The stage one component was comprised of a cloud-based clinical decision support with 24/7 surveillance to detect patients at risk of sepsis. The cloud-based clinical decision support delivered notifications to the patients' designated nurse, who then electronically contacted a provider. The second stage component comprised a sepsis screening and stratification form integrated into the patient electronic health record, essentially an evidence-based decision aid, used by providers to assess patients at bedside. Urban, 284 acute bed community hospital in the USA; 16,000 hospitalisations annually. Data on 2620 adult patients were collected retrospectively in 2014 after the clinical decision support was implemented. 'Suspected infection' was the established gold standard to assess clinical decision support clinimetric performance. A sepsis alert activated on 417 (16%) of 2620 adult patients hospitalised. Applying 'suspected infection' as standard, the patient population characteristics showed 72% sensitivity and 73% positive predictive value. A postalert screening conducted by providers at bedside of 417 patients achieved 81% sensitivity and 94% positive predictive value. Providers documented against 89% patients with an alert activated by clinical decision support and completed 75% of bedside screening and stratification of patients with sepsis within one hour from notification. A clinical decision support binary alarm system with cross-checking functionality improves early recognition and facilitates stratification of patients with sepsis.

Ampleur et impact des évènements indésirables graves liés aux soins: étude d'incidence dans un hôpital du Centre-Est tunisien

PubMed Central

Bouafia, Nabiha; Bougmiza, Iheb; Bahri, Fathi; Letaief, Mondher; Astagneau, Pascal; Njah, Mansour

2013-01-01

Introduction La prévention des événements indésirables représente une priorité de santé du fait de leur fréquence et de leur gravité potentielle. Ce travail a été mené afin d'avoir un diagnostic de la situation épidémiologique relative aux événements indésirables survenant dans notre hôpital. Méthodes Une étude prospective a été menée auprès de tous les patients qui ont été hospitalisés au CHU Farhat Hached - Sousse (Tunisie) sur une période d'un mois dans quatorze services de l'hôpital. La détection d'évènement indésirable grave (EIG) était basée sur les critères adoptés dans différentes études. Les tests T et Chi 2 ont été utilisés pour identifier les facteurs contribuant à l'apparition d'évènements indésirables. Résultats Au total, 162 EIG ont été identifiés pendant la période. 45% de ces évènements étaient des infections nosocomiales. Ces EIG ont eu comme conséquences un décès chez 9,2% des patients, la mise en jeu du pronostic vital de 26% des patients et la prolongation de la durée de séjour chez 61,7% d'entre eux. L'admission dans des circonstances particulières et l'exposition à des soins invasifs étaient identifiés comme des facteurs de risque potentiels EIG. Conclusion Le renforcement de la stratégie de gestion des risques sanitaires en ciblant préférentiellement le risque infectieux constitue une étape fondamentale dans l'amélioration de la sécurité des patients au sein de notre établissement de santé. PMID:24711868

Battage de pieux métalliques dans la roche

NASA Astrophysics Data System (ADS)

Holeyman, Alain

2017-12-01

Le problème du battage d'un pieu tubulaire en acier dans un massif rocheux est abordé sous deux volets : numérique et expérimental. L'approche numérique par éléments finis couplant une modélisation lagrangienne du pieu en mouvement à une modélisation eulérienne du massif en place (approche CEL) permet de suivre l'émergence de la plastification dans le tube en acier en cours de pénétration, naissant en pointe pour se propager vers la tête du pieu. Un cas d'étude en conditions axisymétriques est présenté pour une roche dont la résistance à la compression simple σc vaut 28 MPa. L'approche expérimentale poursuivie en laboratoire a mis en jeu trois matériaux synthétisés sous la forme de monolithes dans lesquels le battage d'un tube en acier inoxydable a été entrepris. Les résultats de ces essais largement instrumentés indiquent que le battage est aisé dans un mortier cellulaire dont la résistance à la compression simple σc n'excède pas 6 MPa mais pratiquement impossible dans un mortier dont la résistance à la compression simple s'approche de 28 MPa. Le battage dans un mortier dont la résistance à la compression simple vaut 11 MPa s'est révélée encore faisable sous une hauteur de chute raisonnable. Les résultats obtenus avec les 3 matériaux mis en œuvre à ce jour indiquent que la résistance unitaire croît depuis environ 2 σc en surface pour atteindre 6 à 8 σc à une pénétration équivalente à 15-20 fois l'épaisseur du tube. Article introduit à la Revue française de Géotechnique en support à la Conférence Coulomb 2017 intitulée « Comportement axial des pieux sous sollicitations dynamiques extrêmes »

Stratification in the lunar regolith - A preliminary view

NASA Technical Reports Server (NTRS)

Duke, M. B.; Nagle, J. S.

1975-01-01

Although our knowledge of lunar regolith stratification is incomplete, several categories of thick and thin strata have been identified. Relatively thick units average 2 to 3 cm in thickness, and appear surficially to be massive. On more detailed examination, these units can be uniformly fine-grained, can show internal trends, or can show internal variations which apparently are random. Other thick units contain soil clasts apparently reworked from underlying units. Thin laminae average approximately 1 mm in thickness; lenticular distribution and composition of some thin laminae indicates that they are fillets shed from adjacent rock fragments. Other dark fine-grained well-sorted thin laminae appear to be surficial zones reworked by micrometeorites. Interpretations of stratigraphic succession can be strengthened by the occurrence of characteristic coarse rock fragments and the orientation of large spatter agglutinates, which are commonly found in their original depositional orientation.

Thermodynamics of inequalities: From precariousness to economic stratification

NASA Astrophysics Data System (ADS)

Smerlak, Matteo

2016-01-01

Growing economic inequalities are observed in several countries throughout the world. Following Pareto, the power-law structure of these inequalities has been the subject of much theoretical and empirical work. But their nonequilibrium dynamics, e.g. after a policy change, remains incompletely understood. Here we introduce a thermodynamical theory of inequalities based on the analogy between economic stratification and statistical entropy. Within this framework we identify the combination of upward mobility with precariousness as a fundamental driver of inequality. We formalize this statement by a "second-law" inequality displaying upward mobility and precariousness as thermodynamic conjugate variables. We estimate the time scale for the "relaxation" of the wealth distribution after a sudden change of the after-tax return on capital. Our method can be generalized to gain insight into the dynamics of inequalities in any Markovian model of socioeconomic interactions.

Overcoming intratumoural heterogeneity for reproducible molecular risk stratification: a case study in advanced kidney cancer.

PubMed

Lubbock, Alexander L R; Stewart, Grant D; O'Mahony, Fiach C; Laird, Alexander; Mullen, Peter; O'Donnell, Marie; Powles, Thomas; Harrison, David J; Overton, Ian M

2017-06-26

Metastatic clear cell renal cell cancer (mccRCC) portends a poor prognosis and urgently requires better clinical tools for prognostication as well as for prediction of response to treatment. Considerable investment in molecular risk stratification has sought to overcome the performance ceiling encountered by methods restricted to traditional clinical parameters. However, replication of results has proven challenging, and intratumoural heterogeneity (ITH) may confound attempts at tissue-based stratification. We investigated the influence of confounding ITH on the performance of a novel molecular prognostic model, enabled by pathologist-guided multiregion sampling (n = 183) of geographically separated mccRCC cohorts from the SuMR trial (development, n = 22) and the SCOTRRCC study (validation, n = 22). Tumour protein levels quantified by reverse phase protein array (RPPA) were investigated alongside clinical variables. Regularised wrapper selection identified features for Cox multivariate analysis with overall survival as the primary endpoint. The optimal subset of variables in the final stratification model consisted of N-cadherin, EPCAM, Age, mTOR (NEAT). Risk groups from NEAT had a markedly different prognosis in the validation cohort (log-rank p = 7.62 × 10 -7 ; hazard ratio (HR) 37.9, 95% confidence interval 4.1-353.8) and 2-year survival rates (accuracy = 82%, Matthews correlation coefficient = 0.62). Comparisons with established clinico-pathological scores suggest favourable performance for NEAT (Net reclassification improvement 7.1% vs International Metastatic Database Consortium score, 25.4% vs Memorial Sloan Kettering Cancer Center score). Limitations include the relatively small cohorts and associated wide confidence intervals on predictive performance. Our multiregion sampling approach enabled investigation of NEAT validation when limiting the number of samples analysed per tumour, which significantly degraded performance

A new offshore transport mechanism for shoreline-released tracer induced by transient rip currents and stratification

NASA Astrophysics Data System (ADS)

Kumar, Nirnimesh; Feddersen, Falk

2017-03-01

Offshore transport from the shoreline across the inner shelf of early-stage larvae and pathogens is poorly understood yet is critical for understanding larval fate and dilution of polluted shoreline water. With a novel coupling of a transient rip current (TRC) generating surf zone model and an ocean circulation model, we show that transient rip currents ejected onto a stratified inner shelf induce a new, previously unconsidered offshore transport pathway. For incident waves and stratification typical for Southern California in the fall, this mechanism subducts surf zone-origin tracers and transports them at least 800 m offshore at 1.2 km/d analogous to subduction at ocean fronts. This mechanism requires both TRCs and stratification. As TRCs are ubiquitous and the inner shelf is often stratified, this mechanism may have an important role in exporting early-stage larvae, pathogens, or other tracers onto the shelf.

Choriorétinite extensive bilatérale révélant une infection par le virus de l'immunodéficience humaine (VIH)

PubMed Central

El Yamouni, Oubaida; Tzili, Nazih; El Hassan, Abdallah; Slassi, Nadia; El Khaoua, Mahfoud; Jebbar, Zakaria; Berraho, Amina

2014-01-01

Au cours de l'infection par le virus de l'immunodéficience humaine(VIH), Les atteintes oculaires sont polymorphes, pouvant compromettre le pronostic fonctionnel. Nous rapportons l'observation d'un patient présentant une choriorétinite infectieuse sévère révélant une infection par le VIH. Patient âgé de 35 ans avec antécédent de tuberculose pulmonaire en 2007, consulte pour BAV bilatérale progressive depuis 6 mois. Une acuité visuelle à compte les doigts au niveau de l'oeil droit et à mouvement des doigts au niveau de l'oeil gauche, avec présence de foyers choriorétiniens diffus visualisés au fond d'oeil et à l'angiographie. Les sérologies VIH, toxoplasmose et CMV sont positives. Le patient a été mis sous traitement anti-toxoplasmose (Sulfadiazine et pyriméthamine) et anti-CMV (Ganciclovir per os). L’évolution sous traitement a été marquée par une régression de la hyalite avec la persistance des foyers choriorétiniens évolutifs et une acuité visuelle réduite à perception lumineuse. PMID:25709723

PIRLS 2011 User Guide for the International Database. Supplement 4: PIRLS 2011 Sampling Stratification Information

ERIC Educational Resources Information Center

Foy, Pierre, Ed.; Drucker, Kathleen T., Ed.

2013-01-01

This supplement contains documentation on the explicit and implicit stratification variables included in the PIRLS 2011 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata are nested within the explicit strata, and were used…

TIMSS 2011 User Guide for the International Database. Supplement 4: TIMSS 2011 Sampling Stratification Information

ERIC Educational Resources Information Center

Foy, Pierre, Ed.; Arora, Alka, Ed.; Stanco, Gabrielle M., Ed.

2013-01-01

This supplement contains documentation on the explicit and implicit stratification variables included in the TIMSS 2011 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata are nested within the explicit strata, and were used…

Bringing the Schools Back in: The Stratification of Educational Achievement in the Chilean Voucher System

ERIC Educational Resources Information Center

Mizala, Alejandra; Torche, Florencia

2012-01-01

This paper analyzes the socioeconomic stratification of achievement in the Chilean voucher system using a census of 4th and 8th graders, a multilevel methodology, and accounting for unobserved selectivity into school sector. Findings indicate that the association between the school's aggregate family socioeconomic status (SES) and test scores is…

Recursive restriction estimation: an alternative to post-stratification in surveys of land and forest cover

Treesearch

Raymond L. Czaplewski

2010-01-01

Numerous government surveys of natural resources use Post-Stratification to improve statistical efficiency, where strata are defined by full-coverage, remotely sensed data and geopolitical boundaries. Recursive Restriction Estimation, which may be considered a special case of the static Kalman filter, is an attractive alternative. It decomposes a complex estimation...

A new map of global ecological land units—An ecophysiographic stratification approach

USGS Publications Warehouse

Sayre, Roger; Dangermond, Jack; Frye, Charlie; Vaughan, Randy; Aniello, Peter; Breyer, Sean P.; Cribbs, Douglas; Hopkins, Dabney; Nauman, Richard; Derrenbacher, William; Wright, Dawn J.; Brown, Clint; Convis, Charles; Smith, Jonathan H.; Benson, Laurence; Van Sistine, Darren; Warner, Harumi; Cress, Jill Janene; Danielson, Jeffrey J.; Hamann, Sharon L.; Cecere, Thomas; Reddy, Ashwan D.; Burton, Devon; Grosse, Andrea; True, Diane; Metzger, Marc; Hartmann, Jens; Moosdorf, Nils; Durr, Hans; Paganini, Marc; Defourny, Pierre; Arino, Olivier; Maynard, Simone; Anderson, Mark; Comer, Patrick

2014-01-01

In response to the need and an intergovernmental commission for a high resolution and data-derived global ecosystem map, land surface elements of global ecological pattern were characterized in an ecophysiographic stratification of the planet. The stratification produced 3,923 terrestrial ecological land units (ELUs) at a base resolution of 250 meters. The ELUs were derived from data on land surface features in a three step approach. The first step involved acquiring or developing four global raster datalayers representing the primary components of ecosystem structure: bioclimate, landform, lithology, and land cover. These datasets generally represent the most accurate, current, globally comprehensive, and finest spatial and thematic resolution data available for each of the four inputs. The second step involved a spatial combination of the four inputs into a single, new integrated raster dataset where every cell represents a combination of values from the bioclimate, landforms, lithology, and land cover datalayers. This foundational global raster datalayer, called ecological facets (EFs), contains 47,650 unique combinations of the four inputs. The third step involved an aggregation of the EFs into the 3,923 ELUs. This subdivision of the Earth’s surface into relatively fine, ecological land areas is designed to be useful for various types of ecosystem research and management applications, including assessments of climate change impacts to ecosystems, economic and non-economic valuation of ecosystem services, and conservation planning.

The Social ecology of Madrid: Stratification in comparative perspective.

PubMed

Abrahamson, M; Johnson, P

1974-08-01

This paper examines the characteristics of residential zones in Madrid, Spain. The primary difference between zones is found to lie in a new bourgeoisie life-style dimension. Working women are found to be the best indicator of this dimension, which also involves servants, natives of Madrid and high degrees of literacy. Fertility-related considerations, however, are unrelated to working women, and this is explained as due to the availability of domestic help and "women-oriented" working arrangements. Fertility and socioeconomic status are found to be interrelated and constitute a second dimension of residential segregation. In conclusion, Madrid is examined in relation to both more and less industrialized cities, leading to a further modification of social area theory contentions concerning the ecology of stratification in developing cities.

Fine-Scale Vertical Stratification and Guild Composition of Saproxylic Beetles in Lowland and Montane Forests: Similar Patterns despite Low Faunal Overlap

PubMed Central

Weiss, Matthias; Procházka, Jiří; Schlaghamerský, Jiří; Cizek, Lukas

2016-01-01

Objective The finer scale patterns of arthropod vertical stratification in forests are rarely studied and poorly understood. Further, there are no studies investigating whether and how altitude affects arthropod vertical stratification in temperate forests. We therefore investigated the fine-scale vertical stratification of diversity and guild structure of saproxylic beetles in temperate lowland and montane forests and compared the resulting patterns between the two habitats. Methods The beetles were sampled with flight intercept traps arranged into vertical transects (sampling heights 0.4, 1.2, 7, 14, and 21 m). A triplet of such transects was installed in each of the five sites in the lowland and in the mountains; 75 traps were used in each forest type. Results 381 species were collected in the lowlands and 236 species in the mountains. Only 105 species (21%) were found at both habitats; in the montane forest as well as in the lowlands, the species richness peaked at 1.2 m, and the change in assemblage composition was most rapid near the ground. The assemblages clearly differed between the understorey (0.4 m, 1.2 m) and the canopy (7 m, 14 m, 21 m) and between the two sampling heights within the understorey, but less within the canopy. The stratification was better pronounced in the lowland, where canopy assemblages were richer than those near the forest floor (0.4 m). In the mountains the samples from 14 and 21 m were more species poor than those from the lower heights. The guild structure was similar in both habitats. Conclusions The main patterns of vertical stratification and guild composition were strikingly similar between the montane and the lowland forest despite the low overlap of their faunas. The assemblages of saproxylic beetles were most stratified near ground. The comparisons of species richness between canopy and understorey may thus give contrasting results depending on the exact sampling height in the understorey. PMID:26978783

Le stress perçu: validation de la traduction d'une échelle de mesure de stress en dialecte marocain

PubMed Central

Loubir, Dalal Ben; Serhier, Zeineb; Otmani, Nada; Housbane, Samy; Mouddene, Naima Ait; Agoub, Mohamed; Othmani, Mohammed Bennani

2015-01-01

Introduction L'article a pour objectif de valider la traduction en dialecte arabe Marocain, de l’échelle du stress perçu « Perceived Stress Scale » chez un large échantillon de la population marocaine. Méthodes Une méthode de traduction et contre traduction en dialecte Marocain a été réalisée pour l’échelle « Perceived Stress Scale » à 10 items. Une étude de type transversale, a été menée par la suite en suivant un échantillonnage par quotas qui a ciblé les individus âgés de plus de 18 ans et appartenant à différentes catégories sociales. Les participants ont répondus aux versions marocaines de l’échelle « Perceived Stress Scale » et d'une version réduite de l’échelle « The Survey of Recent Life Experience ». La validation des qualités métrologiques a été établie en examinant: la fiabilité interne, la fiabilité test-retest, la validité convergente et la structure factorielle. Résultats Cinq cent trente-cinq participants ont répondu aux questionnaires. La version marocaine de l’échelle « Perceived Stress Scale » a présenté une bonne fiabilité interne (α = 0,80) et fiabilité test-retest (CCI= 0,87). D'autant plus, l'analyse en composante principale de l’échelle « Perceived Stress Scale » a permis d'extraire deux facteurs qui ont permis d'expliquer 53,4% de la variance totale. Les deux échelles utilisées étaient assez bien corrélées (r = 0,467, p < 0,01). Conclusion La présente étude a permis d'obtenir une version marocaine de l’échelle « Perceived Stress Scale » avec des propriétés psychométriques satisfaisantes, dont l'utilisation sera d'une grande aide dans la pratique médicale, aussi bien que dans la réalisation des études de recherche qui s'intéressent au stress psychologique. PMID:26587130

Ulcérations buccales et péri-anales: un mode de révélation inhabituel d'une granulomatose avec polyangéite - à propos d'un cas

PubMed Central

Jaafoura, Neirouz Ghannouchi; Thaljaoui, Wathek; Atig, Amira; Bouker, Ahmed; Khalifa, Mabrouk; Bahri, Fathi

2014-01-01

La granulomatose avec polyangéite, est une vascularite systémique rare qui touche avec prédilection les voies aériennes supérieures, les poumons et les reins. L'atteinte cutanéo-muqueuse ainsi que l'atteinte digestive ne sont pas inhabituelles mais elles sont rarement inaugurales de la maladie. Nous rapportons l'observation d'une femme âgée de 57 ans, ayant une granulomatose avec polyangéite multi-systémique avec comme premières manifestations une atteinte cutanéo-muqueuse à type de nécrose de la langue et d'ulcérations péri-anales ainsi que des rectorragies. La présence de signes radiologiques orientant vers une hémmorragie intra-alvéolaire, l'atteinte rénale, l'atteinte neurologique périphérique ainsi que la positivité des C-ANCA de type anti-PR3 ont permis de rattacher les manifestations dermatologiques à cette vascularite. Des manifestations cutanéo-muqueuses atypiques, au cours d'une granulomateuse avec polyangéite, doivent être connues par le clinicien pour un diagnostic et une prise en charge adéquate. PMID:25404981

Developing and validating a novel metabolic tumor volume risk stratification system for supplementing non-small cell lung cancer staging.

PubMed

Pu, Yonglin; Zhang, James X; Liu, Haiyan; Appelbaum, Daniel; Meng, Jianfeng; Penney, Bill C

2018-06-07

We hypothesized that whole-body metabolic tumor volume (MTVwb) could be used to supplement non-small cell lung cancer (NSCLC) staging due to its independent prognostic value. The goal of this study was to develop and validate a novel MTVwb risk stratification system to supplement NSCLC staging. We performed an IRB-approved retrospective review of 935 patients with NSCLC and FDG-avid tumor divided into modeling and validation cohorts based on the type of PET/CT scanner used for imaging. In addition, sensitivity analysis was conducted by dividing the patient population into two randomized cohorts. Cox regression and Kaplan-Meier survival analyses were performed to determine the prognostic value of the MTVwb risk stratification system. The cut-off values (10.0, 53.4 and 155.0 mL) between the MTVwb quartiles of the modeling cohort were applied to both the modeling and validation cohorts to determine each patient's MTVwb risk stratum. The survival analyses showed that a lower MTVwb risk stratum was associated with better overall survival (all p < 0.01), independent of TNM stage together with other clinical prognostic factors, and the discriminatory power of the MTVwb risk stratification system, as measured by Gönen and Heller's concordance index, was not significantly different from that of TNM stage in both cohorts. Also, the prognostic value of the MTVwb risk stratum was robust in the two randomized cohorts. The discordance rate between the MTVwb risk stratum and TNM stage or substage was 45.1% in the modeling cohort and 50.3% in the validation cohort. This study developed and validated a novel MTVwb risk stratification system, which has prognostic value independent of the TNM stage and other clinical prognostic factors in NSCLC, suggesting that it could be used for further NSCLC pretreatment assessment and for refining treatment decisions in individual patients.

Racial and Ethnic Stratification in the Relationship Between Homeownership and Self-Rated Health*

PubMed Central

Finnigan, Ryan

2014-01-01

Social scientists have long demonstrated that socioeconomic resources benefit health. More recently, scholars have begun to examine the potential stratification in the health returns different groups receive for a given resource. Motivated by fundamental cause theory, this paper examines homeownership as a salient health resource with potentially stratified benefits. Homeowners have significantly greater housing quality, wealth, neighborhood quality and integration, and physical and mental health than renters. However, there are compelling theoretical reasons to expect the health advantage of homeownership to be unequally distributed across racial and ethnic groups. Analyses of the 2012 March Current Population Survey initially suggest all homeowners experience a significant health advantage. Further examination finds robust evidence for a homeowner health advantage among Whites, on par with the difference between the married and divorced. The advantage among minority households is considerably smaller, and not significant among Latinos or Asians. Conditioning on a broad array of observable characteristics, White homeowners emerge as exceptionally healthy compared to White renters and all minority groups. This leads to the unexpected finding that racial/ethnic differences in health are concentrated among homeowners. The findings demonstrate the interactive nature of racial/ethnic stratification in health through both access to and returns from socioeconomic resources. PMID:24953499

Effects of Climate Change on Stratification-Destratification Cycles and Resulting Cyanobacterial Blooms in Shallow Lakes of the North Temperate Zone

NASA Astrophysics Data System (ADS)

King, A. T.; Schaffner, L. R.; Gilman, B.; Gronwall, T. R.; Gronwall, D.; Dietz, E. R.; Hairston, N., Jr.

2016-12-01

"Harmful Algal Blooms" of cyanobacteria (cyanoHABs) have become more frequent and larger in extent for inland waters across the globe. Honeoye Lake, the shallowest of the New York State Finger Lakes (9 m max depth, 7 km long), has experienced recent problematic blooms. We use this lake as a model system for understanding the effects of climate change on cyanoHABs in shallow lakes. Cyanobacteria thrive in warm waters with high phosphorus concentrations. While high P is often caused by external nutrient loading via surface runoff, it can also result from internal loading when P-rich sediment is exposed to anoxic/reducing conditions in a lake's hypolimnion after prolonged stratification. In deep lakes, hypolimnetic water remains isolated from the epilimnion throughout the summer with the dissolved P separated from illuminated surface water; in very shallow lakes where the entire water column remains oxygenated/oxidizing, P is bound in insoluble inorganic complexes. However, in lakes of intermediate depth, hypolimnetic water high in soluble reactive P may mix into the photic zone if sufficiently strong winds occur, stimulating a cyanoHAB. We suggest that repeated cycles of stratification, hypolimnetic anoxia, and subsequent mixing may result in "phosphorus pumping" with recurrent cyanoHABs throughout summer. Climate change is causing stronger thermal stratification in lakes through increased surface warming but also causing more frequent storms that can break down stratification in a shallow lake. We use Honeoye Lake as a model system for understanding the extent to which P-pumping occurs and the likely effects of climate change on cyanoHABs. Field data collected in summer 2016 were used to calibrate the publically available General Lake Model (GLM) to predict Honeoye's discontinuous polymictic pattern of stratification punctuated by overturn events and spikes in epilimnetic P and cyanobacterial biomass. We use the calibrated model to determine cyanoHAB incidence as a

Le dermatofibrosarcome de Darier et Ferrand, une tumeur cutanée particulière: à propos de 32 cas et revue de la littérature

PubMed Central

Elamrani, Driss; Droussi, Hatim; Boukind, Samira; Elatiqi, Keltoum; Dlimi, Meriem; Benchamkha, Yassine; Ettalbi, Saloua

2014-01-01

Le dermatofibrosarcome (DFS) est une tumeur fibreuse de la peau, de croissance lente, à très haut risque de récidive locale, mais à potentiel métastatique faible. A partir d'une étude rétrospective étalée sur une période de 5 ans (décembre 2008 - décembre 2013), nous avons analysé les caractéristiques épidémiologiques et cliniques, le délai de diagnostic, le type de thérapeutique et le devenir de 32 patients présentant des tumeurs de Darier et Ferrand histologiquement prouvées. Parmi les 32 patients, 10 se sont présentés initialement au service pour une récidive tumorale. Une discrète prédominance masculine a été notée. Les DFS touchent préférentiellement l'adulte jeune. Le délai diagnostique observé est en moyenne de 4 ans. Le tronc est la localisation préférentielle (60%), suivi par les extrémités proximales (30%). Les 32 patients ont été traités par exérèse chirurgicale avec une marge de 5cm en surface, emportant en profondeur une barrière anatomique saine. La couverture de la perte de substance (PDS) a été réalisée après confirmation anatomopathologique du caractère carcinologique de l'exérèse, et a fait appel à différents moyens allant de la greffe cutanée aux lambeaux musculo –cutanés libres. L’évolution a été marquée par la survenue d'une récidive tumorale chez 8 patients (3 cas parmi les tumeurs vues en première intention et 5 cas parmi les tumeurs vues en récidive) et les résultats ont été jugés satisfaisants sur le plan esthétique et fonctionnel. Le DFS de Darier et Ferrand est une tumeur dont le pronostic et le risque évolutif sont principalement liés au délai diagnostic et la qualité de la première exérèse. Le diagnostic tardif, rend difficile la chirurgie d'exérèse et de reconstruction Les possibilités de guérison en cas de chirurgie primaire bien conduite sont significativement supérieures à celles d'une chirurgie de rattrapage. L'amélioration du pronostic passe par

Contrasting taxonomic stratification of microbial communities in two hypersaline meromictic lakes

PubMed Central

Andrei, Adrian-Ştefan; Robeson, Michael S; Baricz, Andreea; Coman, Cristian; Muntean, Vasile; Ionescu, Artur; Etiope, Giuseppe; Alexe, Mircea; Sicora, Cosmin Ionel; Podar, Mircea; Banciu, Horia Leonard

2015-01-01

Hypersaline meromictic lakes are extreme environments in which water stratification is associated with powerful physicochemical gradients and high salt concentrations. Furthermore, their physical stability coupled with vertical water column partitioning makes them important research model systems in microbial niche differentiation and biogeochemical cycling. Here, we compare the prokaryotic assemblages from Ursu and Fara Fund hypersaline meromictic lakes (Transylvanian Basin, Romania) in relation to their limnological factors and infer their role in elemental cycling by matching taxa to known taxon-specific biogeochemical functions. To assess the composition and structure of prokaryotic communities and the environmental factors that structure them, deep-coverage small subunit (SSU) ribosomal RNA (rDNA) amplicon sequencing, community domain-specific quantitative PCR and physicochemical analyses were performed on samples collected along depth profiles. The analyses showed that the lakes harbored multiple and diverse prokaryotic communities whose distribution mirrored the water stratification patterns. Ursu Lake was found to be dominated by Bacteria and to have a greater prokaryotic diversity than Fara Fund Lake that harbored an increased cell density and was populated mostly by Archaea within oxic strata. In spite of their contrasting diversity, the microbial populations indigenous to each lake pointed to similar physiological functions within carbon degradation and sulfate reduction. Furthermore, the taxonomy results coupled with methane detection and its stable C isotope composition indicated the presence of a yet-undescribed methanogenic group in the lakes' hypersaline monimolimnion. In addition, ultrasmall uncultivated archaeal lineages were detected in the chemocline of Fara Fund Lake, where the recently proposed Nanohaloarchaeota phylum was found to thrive. PMID:25932617

Stratification of Recanalization for Patients with Endovascular Treatment of Intracranial Aneurysms

PubMed Central

Ogilvy, Christopher S.; Chua, Michelle H.; Fusco, Matthew R.; Reddy, Arra S.; Thomas, Ajith J.

2015-01-01

Background With increasing utilization of endovascular techniques in the treatment of both ruptured and unruptured intracranial aneurysms, the issue of obliteration efficacy has become increasingly important. Objective Our goal was to systematically develop a comprehensive model for predicting retreatment with various types of endovascular treatment. Methods We retrospectively reviewed medical records that were prospectively collected for 305 patients who received endovascular treatment for intracranial aneurysms from 2007 to 2013. Multivariable logistic regression was performed on candidate predictors identified by univariable screening analysis to detect independent predictors of retreatment. A composite risk score was constructed based on the proportional contribution of independent predictors in the multivariable model. Results Size (>10 mm), aneurysm rupture, stent assistance, and post-treatment degree of aneurysm occlusion were independently associated with retreatment while intraluminal thrombosis and flow diversion demonstrated a trend towards retreatment. The Aneurysm Recanalization Stratification Scale was constructed by assigning the following weights to statistically and clinically significant predictors. Aneurysm-specific factors: Size (>10 mm), 2 points; rupture, 2 points; presence of thrombus, 2 points. Treatment-related factors: Stent assistance, -1 point; flow diversion, -2 points; Raymond Roy 2 occlusion, 1 point; Raymond Roy 3 occlusion, 2 points. This scale demonstrated good discrimination with a C-statistic of 0.799. Conclusion Surgical decision-making and patient-centered informed consent require comprehensive and accessible information on treatment efficacy. We have constructed the Aneurysm Recanalization Stratification Scale to enhance this decision-making process. This is the first comprehensive model that has been developed to quantitatively predict the risk of retreatment following endovascular therapy. PMID:25621984

Stratification of a cityscape using census and land use variables for inventory of building materials

USGS Publications Warehouse

Rosenfield, G.H.; Fitzpatrick-Lins, K.; Johnson, T.L.

1987-01-01

A cityscape (or any landscape) can be stratified into environmental units using multiple variables of information. For the purposes of sampling building materials, census and land use variables were used to identify similar strata. In the Metropolitan Statistical Area of a cityscape, the census tract is the smallest unit for which census data are summarized and digitized boundaries are available. For purposes of this analysis, census data on total population, total number of housing units, and number of singleunit dwellings were aggregated into variables of persons per square kilometer and proportion of housing units in single-unit dwellings. The level 2 categories of the U.S. Geological Survey's land use and land cover data base were aggregated into variables of proportion of residential land with buildings, proportion of nonresidential land with buildings, and proportion of open land. The cityscape was stratified, from these variables, into environmental strata of Urban Central Business District, Urban Livelihood Industrial Commercial, Urban Multi-Family Residential, Urban Single Family Residential, Non-Urban Suburbanizing, and Non-Urban Rural. The New England region was chosen as a region with commonality of building materials, and a procedure developed for trial classification of census tracts into one of the strata. Final stratification was performed by discriminant analysis using the trial classification and prior probabilities as weights. The procedure was applied to several cities, and the results analyzed by correlation analysis from a field sample of building materials. The methodology developed for stratification of a cityscape using multiple variables has application to many other types of environmental studies, including forest inventory, hydrologic unit management, waste disposal, transportation studies, and other urban studies. Multivariate analysis techniques have recently been used for urban stratification in England. ?? 1987 Annals of Regional

Ocean stratification reduces melt rates at the grounding zone of the Ross Ice Shelf

NASA Astrophysics Data System (ADS)

Begeman, C. B.; Tulaczyk, S. M.; Marsh, O.; Mikucki, J.; Stanton, T. P.; Hodson, T. O.; Siegfried, M. R.; Powell, R. D.; Christianson, K. A.; King, M. A.

2017-12-01

Ocean-driven melting of ice shelves is often invoked as the primary mechanism for triggering ice loss from Antarctica. However, due to the difficulty in accessing the sub-ice-shelf ocean cavity, the relationship between ice-shelf melt rates and ocean conditions is poorly understood, particularly near the transition from grounded to floating ice, known as the grounding zone. Here we present the first borehole oceanographic observations from the grounding zone of Antarctica's largest ice shelf. Contrary to predictions that tidal currents near grounding zones should mix the water column, driving high ice-shelf melt rates, we find a stratified sub-ice-shelf water column. The vertical salinity gradient dominates stratification over a weakly unstable vertical temperature gradient; thus, stratification takes the form of a double-diffusive staircase. These conditions limit vertical heat fluxes and lead to low melt rates in the ice-shelf grounding zone. While modern grounding zone melt rates may presently be overestimated in models that assume efficient tidal mixing, the high sensitivity of double-diffusive staircases to ocean freshening and warming suggests future melt rates may be underestimated, biasing projections of global sea-level rise.

Example study for granular bioreactor stratification: Three-dimensional evaluation of a sulfate-reducing granular bioreactor

PubMed Central

Hao, Tian-wei; Luo, Jing-hai; Su, Kui-zu; Wei, Li; Mackey, Hamish R.; Chi, Kun; Chen, Guang-Hao

2016-01-01

Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the performance of each sludge layer, the internal hydrodynamics and microbial community structures along the height of the reactor. The reactor substratum (the section below baffle 1) was identified as the main acidification zone based on microbial analysis and reactor performance. Two baffle installations increased mixing intensity but at the same time introduced dead zones. Computational fluid dynamics simulation was employed to visualize the internal hydrodynamics. The 16S rRNA gene of the organisms further revealed that more diverse communities of sulfate-reducing bacteria (SRB) and acidogens were detected in the reactor substratum than in the superstratum (the section above baffle 1). The findings of this study shed light on biomass stratification in an SRB granular bioreactor to aid in the design and optimization of such reactors. PMID:27539264

Stratification strategy for evaluating the influence of diabetes complication severity index on the risk of hospitalization: a record linkage data in Western Australia.

PubMed

Ha, Ninh Thi; Harris, Mark; Robinson, Suzanne; Preen, David; Moorin, Rachael

2017-07-01

This study aimed to develop a risk stratification strategy for evaluating the relationship between complications of diabetes and the risk of diabetic-related hospitalization to accurately classify diabetes severity. The study used administrative health records for 40,624 individuals with diabetes aged ≥18years in Western Australian. The adapted Diabetes Complication Severity Index (DCSI), socio-demographic and clinical characteristics were used in random effects negative binomial and threshold effect models to determine the optimal stratification strategy for diabetes severity based on the homogeneity of the risk of hospitalization in response to variation of the DCSI. The optimal stratification of people with diabetes was specified by four sub-populations. The first sub-population was no complications with an inverse association with the risk of hospitalizations (coefficient-0.247, SE 0.03). Further three sub-populations with DCSI at one (coefficient 0.289, SE 0.01), two (coefficient 0.339, SE 0.01) and three or more (coefficient 0.381, SE 0.01) were used to accurately describe the impact of DCSI on the risk of hospitalization. A stratification into four subpopulations based on the homogeneous impact of diabetes DCSI on the risk of hospitalization may be more suitable for evaluating health care interventions and planning health care provision. Copyright © 2017 Elsevier Inc. All rights reserved.

Brugada syndrome: diagnosis, risk stratification, and management.

PubMed

Adler, Arnon

2016-01-01

Asymptomatic patients with Brugada syndrome (BrS) have a small, but not trivial, risk of cardiac events. Their risk stratification and its impact on their management are controversial. The review focuses on the clinical aspects of BrS with special emphasis on the asymptomatic patient. Emerging data suggest that drug and fever-induced type I Brugada patterns are more common than previously appreciated. Although preliminary, these data may imply that asymptomatic patients with induced Brugada pattern are at an even lower risk than currently estimated.The latest data regarding induced ventricular arrhythmias during electrophysiological studies support its use as an indication for an implantable cardioverter defibrillator; however, this issue remains highly controversial.Several new risk markers, such as presence of the Brugada pattern in infero-lateral leads or the concomitant finding of an early repolarization pattern, have recently been proposed. Most asymptomatic BrS patients are at low risk of cardiac events. The presence of new risk markers in this population may prompt consideration of primary prevention measures; however, data supporting this approach are still limited.

Risk Stratification in Arrhythmic Right Ventricular Cardiomyopathy Without Implantable Cardioverter-Defibrillators

PubMed Central

Brun, Francesca; Groeneweg, Judith A.; Gear, Kathleen; Sinagra, Gianfranco; van der Heijden, Jeroen; Mestroni, Luisa; Hauer, Richard N.; Borgstrom, Mark; Marcus, Frank I.; Hughes, Trina

2016-01-01

Objectives The primary objective of this study is risk stratification of patients with arrhythmic right ventricular cardiomyopathy (ARVC). Background There is a need to identify those who need an automatic implantable defibrillator (ICD) to prevent sudden death. Methods This is an analysis of 88 patients with ARVC from three centers who were not treated with an ICD. Results Risk factors for subsequent arrhythmic deaths were pre-enrollment sustained or nonsustained ventricular tachycardia (VT) and decreased left ventricular function. Conclusion These factors serve as proposed guidelines for implantation of an ICD in patients with ARVC to prevent sudden death. PMID:27790640

Stratification of a two-phase monodisperse system in a plane laminar flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedoseev, V. B., E-mail: vbfedoseev@yandex.ru

2016-05-15

A thermodynamic approach is used to describe the distribution of particles of a disperse phase in a plane laminar flow. The effect of the density, shape, and velocity of disperse particles in the flow is considered. Conditions are described under which various modes of stratification of the flow (near-wall, central, intermediate, and multilayer modes) arise. The equilibrium distributions obtained are self-similar; this allows one to compare the behavior of colloidal, highly disperse, coarsely disperse, and coarse-grain systems for various shear velocities and flow widths.

Continental Shelf Embayments of the Eastern Margin of the Philippines; Lamon Bay Stratification & Circulation

DTIC Science & Technology

2012-09-30

Philippines; Lamon Bay Stratification & Circulation Arnold L. Gordon Lamont-Doherty Earth Observatory 61 Route 9W Palisades , NY 10964-8000...AND ADDRESS(ES) Lamont-Doherty Earth Observatory,61 Route 9W, Palisades ,NY,10964-8000 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING...recirculation cell has retreated northward. 7 Figure 5. Solid arrows denote stronger flow, with clear T/S source water signal. LB02 Kuroshio

Fabrication de memoire monoelectronique non volatile par une approche de nanogrille flottante

NASA Astrophysics Data System (ADS)

Guilmain, Marc

Les transistors monoelectroniques (SET) sont des dispositifs de tailles nanometriques qui permettent la commande d'un electron a la fois et donc, qui consomment peu d'energie. Une des applications complementaires des SET qui attire l'attention est son utilisation dans des circuits de memoire. Une memoire monoelectronique (SEM) non volatile a le potentiel d'operer a des frequences de l'ordre des gigahertz ce qui lui permettrait de remplacer en meme temps les memoires mortes de type FLASH et les memoires vives de type DRAM. Une puce SEM permettrait donc ultimement la reunification des deux grands types de memoire au sein des ordinateurs. Cette these porte sur la fabrication de memoires monoelectroniques non volatiles. Le procede de fabrication propose repose sur le procede nanodamascene developpe par C. Dubuc et al. a 1'Universite de Sherbrooke. L'un des avantages de ce procede est sa compatibilite avec le back-end-of-line (BEOL) des circuits CMOS. Ce procede a le potentiel de fabriquer plusieurs couches de circuits memoirestres denses au-dessus de tranches CMOS. Ce document presente, entre autres, la realisation d'un simulateur de memoires monoelectroniques ainsi que les resultats de simulations de differentes structures. L'optimisation du procede de fabrication de dispositifs monoelectroniques et la realisation de differentes architectures de SEM simples sont traitees. Les optimisations ont ete faites a plusieurs niveaux : l'electrolithographie, la gravure de l'oxyde, le soulevement du titane, la metallisation et la planarisation CMP. La caracterisation electrique a permis d'etudier en profondeur les dispositifs formes de jonction de Ti/TiO2 et elle a demontre que ces materiaux ne sont pas appropries. Par contre, un SET forme de jonction de TiN/Al2O3 a ete fabrique et caracterise avec succes a basse temperature. Cette demonstration demontre le potentiel du procede de fabrication et de la deposition de couche atomique (ALD) pour la fabrication de memoires

Career on the move: geography, stratification, and scientific impact.

PubMed

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D; Barabási, Albert-László

2014-04-24

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy.

Career on the Move: Geography, Stratification, and Scientific Impact

NASA Astrophysics Data System (ADS)

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D.; Barabási, Albert-László

2014-04-01

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy.

Atmospheric thermal tides and planetary spin. I. The complex interplay between stratification and rotation

NASA Astrophysics Data System (ADS)

Auclair-Desrotour, P.; Mathis, S.; Laskar, J.

2018-02-01

Context. Thermal atmospheric tides can torque telluric planets away from spin-orbit synchronous rotation, as observed in the case of Venus. They thus participate in determining the possible climates and general circulations of the atmospheres of these planets. Aims: The thermal tidal torque exerted on an atmosphere depends on its internal structure and rotation and on the tidal frequency. Particularly, it strongly varies with the convective stability of the entropy stratification. This dependence has to be characterized to constrain and predict the rotational properties of observed telluric exoplanets. Moreover, it is necessary to validate the approximations used in global modelings such as the traditional approximation, which is used to obtain separable solutions for tidal waves. Methods: We wrote the equations governing the dynamics of thermal tides in a local vertically stratified section of a rotating planetary atmosphere by taking into account the effects of the complete Coriolis acceleration on tidal waves. This allowed us to analytically derive the tidal torque and the tidally dissipated energy, which we used to discuss the possible regimes of tidal dissipation and to examine the key role played by stratification. Results: In agreement with early studies, we find that the frequency dependence of the thermal atmospheric tidal torque in the vicinity of synchronization can be approximated by a Maxwell model. This behavior corresponds to weakly stably stratified or convective fluid layers, as observed previously. A strong stable stratification allows gravity waves to propagate, and makes the tidal torque negligible. The transition is continuous between these two regimes. The traditional approximation appears to be valid in thin atmospheres and in regimes where the rotation frequency is dominated by the forcing or the buoyancy frequencies. Conclusions: Depending on the stability of their atmospheres with respect to convection, observed exoplanets can be tidally

Stratification period and germination of Douglas-fir seed from Oregon seed orchards: two case studies.

Treesearch

Frank C. Sorenson

1991-01-01

Effect of stratification period (S) and incubation temperature (T) on germination be- havior were tested by using two groups of Douglas-fir orchard seedlots that had given low germination percentages in standard tests. One group of seedlots that had experienced different cone-drying regimes, but otherwise were treated comparably, were germinated at T = 15 and 25 °C...

Development of thermal stratification and destratification scaling concepts. Volume 1: Definition of thermal stratification scaling parameters and experimental investigations

NASA Technical Reports Server (NTRS)

Lovrich, T. N.; Schwartz, S. H.

1975-01-01

The dimensionless parameters associated with the thermal stratification and pressure history of a heated container of liquid and its vapor were examined. The Modified Grashof number, the Fourier number, and an Interface number were parameterized using a single test liquid, Freon 113. Cylindrical test tanks with spherical dome end caps were built. Blanket heaters covered the tanks and thermocouples monitored the temperatures of the liquid, the ullage, the tank walls, and the foam insulation encapsulating the tank. A centrifuge was used for the 6 inch tank to preserve the same scaling parameter values between it and the larger tanks. Tests were conducted over a range of Gr* values and the degree of scaling was checked by comparing the dimensionless pressures and temperatures for each scaled pair of tests. Results indicate that the bulk liquid temperature, the surface temperature of the liquid, and the tank pressure can be scaled with the three dimensionless parameters. Some deviation was, however, found in the detailed temperature profiles between the scaled pairs of tests.

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

DOE PAGES

Dempsey, Adam B.; Curran, Scott J.; Wagner, Robert M.

2016-01-14

Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasolinemore » has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this paper, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dempsey, Adam B.; Curran, Scott J.; Wagner, Robert M.

Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasolinemore » has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this paper, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities

A new risk stratification algorithm for the management of patients with adrenal incidentalomas.

PubMed

Birsen, Onur; Akyuz, Muhammet; Dural, Cem; Aksoy, Erol; Aliyev, Shamil; Mitchell, Jamie; Siperstein, Allan; Berber, Eren

2014-10-01

Although adrenal incidentalomas (AI) are detected in ≤5% of patients undergoing chest and abdominal computed tomography (CT), their management is challenging. The current guidelines include recommendations from the National Institutes of Health, the American Association of Endocrine Surgeons (AAES), and the American Association for Cancer Education (AACE). The aim of this study was to develop a new risk stratification model and compare its performance against the existing guidelines for managing AI. A risk stratification model was designed by assigning points for adrenal size (1, 2, or 3 points for tumors <4, 4-6, or >6 cm, respectively) and Hounsfield unit (HU) density on noncontrast CT (1, 2, or 3 points for HU <10, 10-20, or >20, respectively). This model was applied retrospectively to 157 patients with AI managed in an endocrine surgery clinic to assign a score to each tumor. The utility of this model versus the AAES/AACE guidelines was assessed. Of the 157 patients, 54 (34%), had tumors <4 cm with HU <10 (a score of 2). One third of these were hormonally active on biochemical workup and underwent adrenalectomy. The remaining two thirds were nonsecretory lesions and have been followed conservatively with annual testing. In 103 patients (66%), the adrenal mass was >4 cm and/or had indeterminate features on noncontrast CT (HU >10, irregular borders, heterogeneity), and adrenalectomy was performed after hormonal evaluation was completed (10 were hormonally active on biochemical testing). Seven of these patients (7%) had adrenocortical cancer on final pathology with tumor size <4 cm in 0, 4-6 cm in 1, and >6 cm in 5 patients. Of the hormonally inactive patients, 32% had a score of 3, 38% 4, and 30% 5 or 6. The incidence of adrenocortical cancer in these subgroups was 0, 0, and 25%, respectively. This study shows that an algorithm that utilizes the hormonal activity at the first decision step followed by a consolidated risk stratification, based on tumor

Variation spatiotemporelle de la cryptorchidie et de l’hypospadias au Québec : Une étude exploratoire

PubMed Central

Guertin, Sophie; Lemieux, Karine-Sylvie; Makhoulian, Natalie; Michaud, Sébastien; Patry, Rose-Marie; Côté, Anne-Andrée; Gagnon, Fabien; Ayotte, Pierre; Bolduc, Stéphane

2011-01-01

Résumé Objectifs : La majorité des études effectuées au cours des dernières décennies ont mis en évidence une augmentation du nombre de cas de cryptorchidie et d’hypospadias entre 1970 et 1990. De plus, l’importante variabilité géographique de ces anomalies est bien décrite. Cette étude vise à mesurer la prévalence à la naissance de la cryptorchidie et de l’hypospadias au Québec, à vérifier si ces anomalies sont en augmentation et à en évaluer la répartition interrégionale. Méthode : Une étude épidémiologique descriptive a été réalisée à partir du nombre de garçons de cinq ans et moins hospitalisés pour une cryptorchidie ou un hypospadias au Québec de 1989 à 2004 selon les données du fichier administratif d’hospitalisation MED-ÉCHO. Les données sur les naissances provenaient de l’Institut de la statistique du Québec. Résultats : La prévalence annuelle moyenne pour 1000 naissances vivantes de sexe masculin est de 19,1 (IC à 95 % : 18,8–19,4) pour la cryptorchidie et 11,4 (IC à 95 % 11,1–11,6) pour l’hypospadias au Québec. Au cours de la période étudiée, la prévalence de cryptorchidie a légèrement diminué, alors que celle de l’hypospadias est demeurée stable. Comparativement à la province du Québec, des régions présentent une prévalence significativement différente de cryptorchidie et/ou d’hypospadias. . Conclusion : Au Québec, la prévalence de cryptorchidie est en légère diminution alors que celle de l’hypospadias est stable. Des variations régionales significatives sont observables. D’autres études sont nécessaires afin d’évaluer l’hypothèse d’un lien avec les contaminants environnementaux en émergence. L’implantation d’un système de surveillance des anomalies congénitales permettrait une représentation plus valide de la situation. PMID:21672476

Variation spatiotemporelle de la cryptorchidie et de l'hypospadias au Québec : Une étude exploratoire.

PubMed

Guertin, Sophie; Lemieux, Karine-Sylvie; Makhoulian, Natalie; Michaud, Sébastien; Patry, Rose-Marie; Côté, Anne-Andrée; Gagnon, Fabien; Ayotte, Pierre; Bolduc, Stéphane

2011-06-01

RéSUMé: : La majorité des études effectuées au cours des dernières décennies ont mis en évidence une augmentation du nombre de cas de cryptorchidie et d'hypospadias entre 1970 et 1990. De plus, l'importante variabilité géographique de ces anomalies est bien décrite. Cette étude vise à mesurer la prévalence à la naissance de la cryptorchidie et de l'hypospadias au Québec, à vérifier si ces anomalies sont en augmentation et à en évaluer la répartition interrégionale. MéTHODE :: Une étude épidémiologique descriptive a été réalisée à partir du nombre de garçons de cinq ans et moins hospitalisés pour une cryptorchidie ou un hypospadias au Québec de 1989 à 2004 selon les données du fichier administratif d'hospitalisation MED-ÉCHO. Les données sur les naissances provenaient de l'Institut de la statistique du Québec. RéSULTATS :: La prévalence annuelle moyenne pour 1000 naissances vivantes de sexe masculin est de 19,1 (IC à 95 % : 18,8-19,4) pour la cryptorchidie et 11,4 (IC à 95 % 11,1-11,6) pour l'hypospadias au Québec. Au cours de la période étudiée, la prévalence de cryptorchidie a légèrement diminué, alors que celle de l'hypospadias est demeurée stable. Comparativement à la province du Québec, des régions présentent une prévalence significativement différente de cryptorchidie et/ou d'hypospadias. . : Au Québec, la prévalence de cryptorchidie est en légère diminution alors que celle de l'hypospadias est stable. Des variations régionales significatives sont observables. D'autres études sont nécessaires afin d'évaluer l'hypothèse d'un lien avec les contaminants environnementaux en émergence. L'implantation d'un système de surveillance des anomalies congénitales permettrait une représentation plus valide de la situation.

Development of a Bayesian Classifier for Breast Cancer Risk Stratification: A Feasibility Study

DTIC Science & Technology

2010-03-29

IV 0 2 10 23 BIRADS V 0 1 2 1 No mammogram 116 94 55 45 Breast biopsy category .4076 Benign, no atypia 19 12 27 34 Premalignant 1 0 2 4 Infiltrating... breast EIS result∗ Estimated outcome, % Known evidence Biopsy category EIS Gail Benign, no Infiltrating cancer Case frequency, % result cutoff‘ atypia or...Development of a Bayesian Classifier for Breast Cancer Risk Stratification: A Feasibility Study Alexander Stojadinovic, MD,a,b Christina Eberhardt,a

The effect of different biologic and biosynthetic wound covers on keratinocyte growth, stratification and differentiation in vitro

PubMed Central

Mestak, Ondrej

2014-01-01

The purpose of this study was to compare, by means of in vitro cultivation technique, five marketed brands of wound covers used in the treatment of burns and other skin defects (Biobrane®, Suprathel®, Veloderm®, Xe-Derma®, and Xenoderm®) for their ability to stimulate the keratinocyte growth, stratification, and differentiation. In three independent experiments, human keratinocytes were grown on the tested covers in organotypic cultures by the 3T3 feeder layer technique. Vertical paraffin sections of the wound covers with keratinocytes were processed using hematoxylin–eosin staining and immunostaining for involucrin. Keratinocyte populations on the dressings were assessed for (1) number of keratinocyte strata (primary variable), (2) quantitative growth, (3) thickness of the keratinocyte layer, and (4) cell differentiation. The Xe-Derma wound cover provided the best support to keratinocyte proliferation and stratification, with the number of keratinocyte strata significantly (p < 0.05) higher in comparison to all products studied, except Xenoderm. However, in contrast to Xe-Derma, Xenoderm did not significantly differ from the other dressings. The results of this in vitro study show that the brands based on porcine dermal matrix possess the strongest effect on keratinocyte proliferation and stratification. The distinctive position of Xe-Derma may be related to its composition, where natural dermal fibers form a smooth surface, similar to the basement membrane. Furthermore, the results indicate that in vitro evaluation of effects on epithelial growth may accelerate the development of new bio-engineering-based wound covers. PMID:25383177

Distribution and exploitation of Nile perch Lates niloticus in relation to stratification in Lake Victoria, East Africa

USGS Publications Warehouse

Taabu-Munyaho, A.; Kayanda, Robert J.; Everson, Inigo; Grabowski, Timothy B.; Marteinsdóttir, Gudrún

2013-01-01

Stratification restricts habitable areas forcing fish to balance between favourable temperature and minimum dissolved oxygen requirements. Acoustic surveys conducted during the stratified and isothermal periods on tropical Lake Victoria indicated that stratification of temperature and dissolved oxygen (DO) affected vertical distribution of Nile perch. There was higher mean temperature (25.6 ± 0.5 °C) and lower DO (6.4 ± 1.8 mg/l) during stratified period compared to the isothermal period (mean temperature 24.9 ± 0.3 °C; mean DO 7.3 ± 0.6 mg/l). Higher mean densities of Nile perch were recorded in the coastal (0.44 ± 0.03) and deep (0.27 ± 0.02 g/m3) strata during the stratified compared to the isothermal season (coastal: 0.24 ± 0.01; deep: 0.12 ± 0.02 g/m3). In addition, Nile perch density in the upper 0–40 m depth layers in the coastal and deep strata increased by over 50% from the isothermal to the stratified season. Daily landings from 65 motorised fishing boats between October 2008 and September 2010 show higher mean catch (26.29 ± 0.17 kg/boat/day) during stratified compared to the isothermal (23.59 ± 0.15) season. Thermal stratification apparently compresses the habitat available to Nile perch and can potentially result in higher exploitation. Managers should evaluate the potential benefits of instituting closed seasons during the stratified period, and stock assessment models should take into account the seasonal niche compression.

Utilising monitoring and modelling of estuarine environments to investigate catchment conditions responsible for stratification events in a typically well-mixed urbanised estuary

NASA Astrophysics Data System (ADS)

Lee, Serena B.; Birch, Gavin F.

2012-10-01

Estuarine health is affected by contamination from stormwater, particularly in highly-urbanised environments. For systems where catchment monitoring is insufficient, novel techniques must be employed to determine the impact of urban runoff on receiving water bodies. In the present work, estuarine monitoring and modelling were successfully employed to determine stormwater runoff volumes and establish an appropriate rainfall/runoff relationship capable of replicating fresh-water discharge due to the full range of precipitation conditions in the Sydney Estuary, Australia. Using estuary response to determine relationships between catchment rainfall and runoff is a widely applicable method and may be of assistance in the study of waterways where monitoring fluvial discharges is not practical or is beyond the capacity of management authorities. For the Sydney Estuary, the SCS-CN method replicated rainfall/runoff and was applied in numerical modelling experiments investigating the hydrodynamic characteristics affecting stratification and estuary recovery following high precipitation. Numerical modelling showed stratification in the Sydney Estuary was dominated by fresh-water discharge. Spring tides and up-estuary winds contributed to mixing and neap tides and down-estuary winds enhanced stratification.

Stratification-Based Outlier Detection over the Deep Web.

PubMed

Xian, Xuefeng; Zhao, Pengpeng; Sheng, Victor S; Fang, Ligang; Gu, Caidong; Yang, Yuanfeng; Cui, Zhiming

2016-01-01

For many applications, finding rare instances or outliers can be more interesting than finding common patterns. Existing work in outlier detection never considers the context of deep web. In this paper, we argue that, for many scenarios, it is more meaningful to detect outliers over deep web. In the context of deep web, users must submit queries through a query interface to retrieve corresponding data. Therefore, traditional data mining methods cannot be directly applied. The primary contribution of this paper is to develop a new data mining method for outlier detection over deep web. In our approach, the query space of a deep web data source is stratified based on a pilot sample. Neighborhood sampling and uncertainty sampling are developed in this paper with the goal of improving recall and precision based on stratification. Finally, a careful performance evaluation of our algorithm confirms that our approach can effectively detect outliers in deep web.

Stratification-Based Outlier Detection over the Deep Web

PubMed Central

Xian, Xuefeng; Zhao, Pengpeng; Sheng, Victor S.; Fang, Ligang; Gu, Caidong; Yang, Yuanfeng; Cui, Zhiming

2016-01-01

For many applications, finding rare instances or outliers can be more interesting than finding common patterns. Existing work in outlier detection never considers the context of deep web. In this paper, we argue that, for many scenarios, it is more meaningful to detect outliers over deep web. In the context of deep web, users must submit queries through a query interface to retrieve corresponding data. Therefore, traditional data mining methods cannot be directly applied. The primary contribution of this paper is to develop a new data mining method for outlier detection over deep web. In our approach, the query space of a deep web data source is stratified based on a pilot sample. Neighborhood sampling and uncertainty sampling are developed in this paper with the goal of improving recall and precision based on stratification. Finally, a careful performance evaluation of our algorithm confirms that our approach can effectively detect outliers in deep web. PMID:27313603

Le transfert de connaissances entre les mathematiques et les sciences. Une etude exploratoire aupres d'eleves de 4e secondaire

NASA Astrophysics Data System (ADS)

Samson, Ghislain

2003-06-01

Au moment ou dans plusieurs pays on travaille a refondre les programmes d'etudes, tant au primaire qu'au secondaire, l'interet pour le transfert renait. Un des concepts fondamentaux en apprentissage consiste en l'habilete a reutiliser de facon consciente et efficace un acquis d'une situation a une autre situation. Cette recherche emane de preoccupations professionnelles au moment ou le chercheur etait enseignant au secondaire. Au cours de ces annees, il lui a ete possible de constater que plusieurs eleves percevaient difficilement les liens presents entre les disciplines mathematiques et scientifiques. Des travaux en psychologie cognitive et plus particulierement selon une perspective du traitement de l'information ont servi de cadre de reference pour evaluer et analyser les capacites de transfert aupres d'eleves de 4e secondaire. Ce cadre de reference permet de formuler le principal objectif qui est de mieux comprendre le processus de transfert chez des eleves en situation de resolution de problemes scientifiques. Cette these s'interesse donc au transfert en tant que phenomene important du processus d'apprentissage au sens de l'integration. La methode de recherche choisie, de nature qualitative, est principalement axee sur l'evaluation de la capacite a transferer des connaissances lors d'une epreuve et d'un entretien. Pour evaluer ce potentiel de transfert, nous avons elabore deux outils: une epreuve en mathematiques et en sciences et un guide d'entretien. Pour la passation de l'epreuve, le chercheur a pu compter sur la collaboration de 130 sujets provenant de deux ecoles. L'entretien complete la prise de donnees avec 13 sujets ayant accepte de poursuivre l'etude. Les donnees recueillies par ces instruments font ensuite l'objet d'une analyse de contenu. En premier lieu, les verbatims de l'epreuve et de l'entretien ont ete transcrits, puis codifies. La correction des reponses fournies pour les problemes resolus s'est faite a partir d'une grille d

Development of a Reduced-Order Three-Dimensional Flow Model for Thermal Mixing and Stratification Simulation during Reactor Transients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Rui

2017-09-03

Mixing, thermal-stratification, and mass transport phenomena in large pools or enclosures play major roles for the safety of reactor systems. Depending on the fidelity requirement and computational resources, various modeling methods, from the 0-D perfect mixing model to 3-D Computational Fluid Dynamics (CFD) models, are available. Each is associated with its own advantages and shortcomings. It is very desirable to develop an advanced and efficient thermal mixing and stratification modeling capability embedded in a modern system analysis code to improve the accuracy of reactor safety analyses and to reduce modeling uncertainties. An advanced system analysis tool, SAM, is being developedmore » at Argonne National Laboratory for advanced non-LWR reactor safety analysis. While SAM is being developed as a system-level modeling and simulation tool, a reduced-order three-dimensional module is under development to model the multi-dimensional flow and thermal mixing and stratification in large enclosures of reactor systems. This paper provides an overview of the three-dimensional finite element flow model in SAM, including the governing equations, stabilization scheme, and solution methods. Additionally, several verification and validation tests are presented, including lid-driven cavity flow, natural convection inside a cavity, laminar flow in a channel of parallel plates. Based on the comparisons with the analytical solutions and experimental results, it is demonstrated that the developed 3-D fluid model can perform very well for a wide range of flow problems.« less

A panel of ancestry informative markers to estimate and correct potential effects of population stratification in Han Chinese.

PubMed

Qin, Pengfei; Li, Zhiqiang; Jin, Wenfei; Lu, Dongsheng; Lou, Haiyi; Shen, Jiawei; Jin, Li; Shi, Yongyong; Xu, Shuhua

2014-02-01

Population stratification acts as a confounding factor in genetic association studies and may lead to false-positive or false-negative results. Previous studies have analyzed the genetic substructures in Han Chinese population, the largest ethnic group in the world comprising ∼20% of the global human population. In this study, we examined 5540 Han Chinese individuals with about 1 million single-nucleotide polymorphisms (SNPs) and screened a panel of ancestry informative markers (AIMs) to facilitate the discerning and controlling of population structure in future association studies on Han Chinese. Based on genome-wide data, we first confirmed our previous observation of the north-south differentiation in Han Chinese population. Second, we developed a panel of 150 validated SNP AIMs to determine the northern or southern origin of each Han Chinese individual. We further evaluated the performance of our AIMs panel in association studies in simulation analysis. Our results showed that this AIMs panel had sufficient power to discern and control population stratification in Han Chinese, which could significantly reduce false-positive rates in both genome-wide association studies (GWAS) and candidate gene association studies (CGAS). We suggest this AIMs panel be genotyped and used to control and correct population stratification in the study design or data analysis of future association studies, especially in CGAS which is the most popular approach to validate previous reports on genetic associations of diseases in post-GWAS era.

Validation de la version francophone d’une échelle composite multidimensionnelle pour l’évaluation de la douleur postopératoire chez les chats

PubMed Central

Steagall, Paulo V.M.; Monteiro, Beatriz P.; Lavoie, Anne-Marie; Frank, Diane; Troncy, Eric; Luna, Stelio P.L.; Brondani, Juliana T.

2017-01-01

Résumé L’objectif de cette étude était de valider la version francophone de l’échelle composite multidimensionnelle de douleur UNESP-Botucatu (MCPS-Fr) chez les chats. Deux vétérinaires et une étudiante de médecine vétérinaire francophones ont identifié trois catégories de comportements distincts sur des vidéos : «les changements psychomoteurs», «la protection de la région douloureuse» et «les variables physiologiques». La cohérence interne était excellente (score total du coefficient alpha de Cronbach était de 0,94; 0,90; et 0,61, respectivement). La bonne concordance entre les évaluations à l’aveugle des observateurs et l’évaluateur de référence confirme la validité de cet instrument. La fiabilité inter- et intra-évaluateur était bonne à très bonne. Le point limite optimal pour l’analgésie de secours, identifié avec une courbe ROC, était au-delà de 7 (échelle allant de 0 à 30 points), avec une sensibilité de 97,8 % et une spécificité de 99,1 %. La MCPS-Fr est un outil valide et sensible pour l’évaluation de la douleur aiguë chez les chattes ayant subi une ovariohystérectomie. PMID:28042156

Racial and ethnic stratification in the relationship between homeownership and self-rated health.

PubMed

Finnigan, Ryan

2014-08-01

Social scientists have long demonstrated that socioeconomic resources benefit health. More recently, scholars have begun to examine the potential stratification in the health returns different groups receive for a given resource. Motivated by fundamental cause theory, this paper examines homeownership as a salient health resource with potentially stratified benefits. Homeowners have significantly greater housing quality, wealth, neighborhood quality and integration, and physical and mental health than renters. However, there are compelling theoretical reasons to expect the health advantage of homeownership to be unequally distributed across racial and ethnic groups. Regression analyses of 71,874 household heads in the United States from the 2012 March Current Population Survey initially suggest all homeowners experience a significant health advantage. Further examination finds robust evidence for a homeowner health advantage among Whites, on par with the difference between the married and divorced. The advantage among minority households is considerably smaller, and not significant among Latinos or Asians. Conditioning on a broad array of observable characteristics, White homeowners emerge as exceptionally healthy compared to White renters and all minority groups. This leads to the unexpected finding that racial/ethnic differences in health are concentrated among homeowners. The findings demonstrate the interactive nature of racial/ethnic stratification in health through both access to and returns from socioeconomic resources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Radio Emission from Three-dimensional Relativistic Hydrodynamic Jets: Observational Evidence of Jet Stratification

NASA Astrophysics Data System (ADS)

Aloy, Miguel-Angel; Gómez, José-Luis; Ibáñez, José-María; Martí, José-María; Müller, Ewald

2000-01-01

We present the first radio emission simulations from high-resolution three-dimensional relativistic hydrodynamic jets; these simulations allow us to study the observational implications of the interaction between the jet and the external medium. This interaction gives rise to a stratification of the jet in which a fast spine is surrounded by a slow high-energy shear layer. The stratification (in particular, the large specific internal energy and slow flow in the shear layer) largely determines the emission from the jet. If the magnetic field in the shear layer becomes helical (e.g., resulting from an initial toroidal field and an aligned field component generated by shear), the emission shows a cross section asymmetry, in which either the top or the bottom of the jet dominates the emission. This, as well as limb or spine brightening, is a function of the viewing angle and flow velocity, and the top/bottom jet emission predominance can be reversed if the jet changes direction with respect to the observer or if it presents a change in velocity. The asymmetry is more prominent in the polarized flux because of field cancellation (or amplification) along the line of sight. Recent observations of jet cross section emission asymmetries in the blazar 1055+018 can be explained by assuming the existence of a shear layer with a helical magnetic field.

Evidence-based Guidelines for Precision Risk Stratification-Based Screening (PRSBS) for Colorectal Cancer: Lessons learned from the US Armed Forces: Consensus and Future Directions

PubMed Central

Avital, Itzhak; Langan, Russell C.; Summers, Thomas A.; Steele, Scott R.; Waldman, Scott A.; Backman, Vadim; Yee, Judy; Nissan, Aviram; Young, Patrick; Womeldorph, Craig; Mancusco, Paul; Mueller, Renee; Noto, Khristian; Grundfest, Warren; Bilchik, Anton J.; Protic, Mladjan; Daumer, Martin; Eberhardt, John; Man, Yan Gao; Brücher, Björn LDM; Stojadinovic, Alexander

2013-01-01

Colorectal cancer (CRC) is the third most common cause of cancer-related death in the United States (U.S.), with estimates of 143,460 new cases and 51,690 deaths for the year 2012. Numerous organizations have published guidelines for CRC screening; however, these numerical estimates of incidence and disease-specific mortality have remained stable from years prior. Technological, genetic profiling, molecular and surgical advances in our modern era should allow us to improve risk stratification of patients with CRC and identify those who may benefit from preventive measures, early aggressive treatment, alternative treatment strategies, and/or frequent surveillance for the early detection of disease recurrence. To better negotiate future economic constraints and enhance patient outcomes, ultimately, we propose to apply the principals of personalized and precise cancer care to risk-stratify patients for CRC screening (Precision Risk Stratification-Based Screening, PRSBS). We believe that genetic, molecular, ethnic and socioeconomic disparities impact oncological outcomes in general, those related to CRC, in particular. This document highlights evidence-based screening recommendations and risk stratification methods in response to our CRC working group private-public consensus meeting held in March 2012. Our aim was to address how we could improve CRC risk stratification-based screening, and to provide a vision for the future to achieving superior survival rates for patients diagnosed with CRC. PMID:23459409

Folie à Trois à Lubumbashi: à propos d’un cas

PubMed Central

Bugeme, Marcellin; Mukuku, Olivier; Mobambo, Pitchou; Koba, Bora; Muyumba, Emmanuel

2013-01-01

Le trouble psychotique partagé est une entité psychiatrique rare caractérisée par la transmission des idées délirantes d’un patient dit “inducteur”, à un autre dit “induit”, tous vivant en association proche, dans un milieu clos et isolé, partageant des idées délirantes sur le même thème. Nous vous rapportons un cas clinique de “folie à trois” mettant en jeu un délire de persécution à mécanisme hallucinatoire et interprétatif par trois soeurs de même famille biologique, orphelines de père, vivant ensemble, ayant un niveau socio-économique bas après la mort de leur père. Elles ont des relations étroitement liéeset font leurs activités ensemble. L’aînée étant parvenue à partager ses idées délirantes avec ses soeurs et toutes troisse sont retrouvées dans un état d’excitation psychomotrice. PMID:23560130

Une version canadienne française du Lower Extremity Functional Scale (LEFS) : L'Échelle fonctionnelle des membres inférieurs (ÉFMI), partie I

PubMed Central

René, Frédéric; Casimiro, Lynn; Tremblay, Manon; Lefebvre, Annabelle; Beaudouin, Martine; Belliveau, Véronik; Bergeron, Louis-Philippe

2011-01-01

RÉSUMÉ Introduction : Le Rehabilitation Network of Ottawa-Carleton (RENOC) recommande à ses établissements de santé d'utiliser le Lower Extremity Functional Scale (LEFS). Puisque le RENOC dessert une clientèle anglophone et francophone, il s'imposait de traduire le LEFS pour l'évaluation de la clientèle francophone. But : Produire une traduction canadienne-française du LEFS sous l'appellation proposée « Échelle fonctionnelle des membres inférieurs (ÉFMI) » et examiner la validité de son contenu. Méthodologie : Nous avons utilisé une approche modifiée de la méthodologie de validation transculturelle de questionnaires de Vallerand (1989). Une traduction renversée parallèle du LEFS a d'abord été complétée. Ensuite, un comité d'experts a examiné les deux versions préliminaires et a créé la première version expérimentale de l'ÉFMI. Cette version fut évaluée par un deuxième comité d'experts, dont les commentaires menèrent à une deuxième version expérimentale. Finalement, 35 professionnels de la réadaptation évaluèrent la version expérimentale de l'ÉFMI sur une échelle d'ambiguïté et proposèrent les modifications finales. Résultats : Pour les différents énoncés de la version finale de l'ÉFMI, les moyennes sur l'échelle d'ambiguïté démontrent un niveau d'ambiguïté relativement faible puisqu'elles varient entre 1 et 2.54. Conclusion : Les quatre étapes rigoureuses du processus ont permis de produire une version valide du LEFS en français. PMID:22379265

Exploring Organisational Stratification and Technological Pedagogical Change: Cases of Technology Integration Specialists in Hong Kong International Schools

ERIC Educational Resources Information Center

Woo, David James

2015-01-01

An international school may make organisational choices that divide the school by curriculum, grade-level, language and location. This article explores how a school's organisational stratification impacts how the school supports changing teaching and learning practices through technology. The article draws from case data of technology integration…

Fundamental Causes of Health Disparities: Stratification, the Welfare State, and Health in the United States and Iceland

ERIC Educational Resources Information Center

Olafsdottir, Sigrun

2007-01-01

Research has established that those with higher social status have better health. Less is known about whether this relationship differs cross-nationally and whether it operates similarly across different institutional arrangements. To examine the relationship between stratification and health, two Western, industrialized societies at opposite ends…

On Evaluating circulation and temperature stratification under changing water levels in Lake Mead with a 3D hydrodynamic model

NASA Astrophysics Data System (ADS)

Li, Y.; Acharya, K.; Chen, D.; Stone, M.; Yu, Z.; Young, M.; Zhu, J.; Shafer, D. S.; Warwick, J. J.

2009-12-01

Sustained drought in the western United States since 2000 has led to a significant drop (about 35 meters) in the water level of Lake Mead, the largest reservoir by volume in United States. The drought combined with rapid urban development in southern Nevada and emergence of invasive species has threatened the water quality and ecological processes in Lake Mead. A three-dimensional hydrodynamic model, Environmental Fluid Dynamics Code (EFDC), was applied to investigate lake circulation and temperature stratification in parts of Lake Mead (Las Vegas Bay and Boulder Basin) under changing water levels. Besides the inflow from Las Vegas Wash and the Colorado River, the model considered atmospheric changes as well as the boundary conditions restricted by the operation of Hoover Dam. The model was calibrated and verified by using observed data including water level, velocity, and temperature from 2003 and 2005. The model was applied to study the hydrodynamic processes at water level 366.8 m (year 2000) and at water level 338.2 m (year 2008). The high-stage simulation described the pre-drought lake hydrodynamic processes while the low-stage simulation highlighted the drawdown impact on such processes. The results showed that both inflow and wind-driven mixing process played major roles in the thermal stratification and lake circulation in both cases. However, the atmospheric boundary played a more important role than inflow temperature on thermal stratification of Lake Mead during water level decline. Further, the thermal stratification regime and flow circulation pattern in shallow lake regions (e.g.., the Boulder Basin area) were most impacted. The temperature of the lake at the high-stage was more sensitive to inflow temperatures than at low-stage. Furthermore, flow velocities decreased with the decreasing water level due to reduction in wind impacts, particularly in shallow areas of the lake. Such changes in temperature and lake current due to present drought have a

Career on the Move: Geography, Stratification, and Scientific Impact

PubMed Central

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D.; Barabási, Albert-László

2014-01-01

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy. PMID:24759743

Prognostic factors and risk stratification in patients with castration-resistant prostate cancer receiving docetaxel-based chemotherapy.

PubMed

Yamashita, Shimpei; Kohjimoto, Yasuo; Iguchi, Takashi; Koike, Hiroyuki; Kusumoto, Hiroki; Iba, Akinori; Kikkawa, Kazuro; Kodama, Yoshiki; Matsumura, Nagahide; Hara, Isao

2016-03-22

While novel drugs have been developed, docetaxel remains one of the standard initial systemic therapies for castration-resistant prostate cancer (CRPC) patients. Despite the excellent anti-tumor effect of docetaxel, its severe adverse effects sometimes distress patients. Therefore, it would be very helpful to predict the efficacy of docetaxel before treatment. The aims of this study were to evaluate the potential value of patient characteristics in predicting overall survival (OS) and to develop a risk classification for CRPC patients treated with docetaxel-based chemotherapy. This study included 79 patients with CRPC treated with docetaxel. The variables, including patient characteristics at diagnosis and at the start of chemotherapy, were retrospectively collected. Prognostic factors predicting OS were analyzed using the Cox proportional hazard model. Risk stratification for overall survival was determined based on the results of multivariate analysis. PSA response ≥50 % was observed in 55 (69.6 %) of all patients, and the median OS was 22.5 months. The multivariate analysis showed that age, serum PSA level at the start of chemotherapy, and Hb were independent prognostic factors for OS. In addition, ECOG performance status (PS) and the CRP-to-albumin ratio were not significant but were considered possible predictors for OS. Risk stratification according to the number of these risk factors could effectively stratify CRPC patients treated with docetaxel in terms of OS. Age, serum PSA level at the start of chemotherapy, and Hb were identified as independent prognostic factors of OS. ECOG PS and the CRP-to-albumin ratio were not significant, but were considered possible predictors for OS in Japanese CRPC patients treated with docetaxel. Risk stratification based on these factors could be helpful for estimating overall survival.

[Exercise stress test and dobutamine stress echocardiography for the prognostic stratification after uncomplicated acute myocardial infarction].

PubMed

Vitiello, Nicola; Cirillo, Raffaele; Granato, Luigi; Coppola, Vincenzo; di Palma, Francesco

2007-05-01

Exercise stress test and dobutamine stress echocardiography are usually performed early after an uncomplicated acute myocardial infarction in the prognostic stratification of patients to define the optimal diagnostic and therapeutic procedure. The aim of this study was to evaluate if the association of an imaging test could increase exercise test capability to identify patients with residual ischemia and patients at high risk of events in the follow-up. Four hundred and forty-two consecutive patients underwent exercise stress testing and dobutamine stress echocardiography before discharge and subsequently coronary angiography within 30 days. In case of submaximal negative result at the exercise test, this was repeated 20 days after discharge. The follow-up lasted 26.8 +/- 9 months. The endpoints were death, reinfarction, and unstable angina requiring hospitalization or revascularization intervention. Both tests and their association showed a higher sensitivity in males; in females dobutamine stress echocardiography had a higher specificity. In females, the addition of dobutamine stress echocardiography increased either the negative or the positive prognostic values of exercise stress test by 31% and 5.6%, respectively. In males, the negative prognostic value increased by 15.5%, whereas the positive prognostic value decreased by 12%. A low exercise capability (<6 METs) showed an event predictive value independent of test results and any other variables. The event-free survival curves correlated with exercise capability differed shortly after the first months both in males and females. These results suggest different stratification procedures with regard to gender: in males, the exercise stress test might be sufficient at discharge, to be repeated 20 days later, if submaximal negative. In females, it seems to be useful to associate an imaging test at discharge. In any case, the exercise stress test remains the main step in the stratification procedure also for its

Dynamics of a vertical turbulent plume in a stratification typical of Greenland fjords: an idealized model of subglacial discharge

NASA Astrophysics Data System (ADS)

Stenberg, Erik; Ezhova, Ekaterina; Cenedese, Claudia; Brandt, Luca

2017-04-01

We the report results of large eddy simulations of a turbulent buoyant plume in a configuration providing an idealized model of subglacial discharge from a submarine glacier in stratifications typical of Greenland Fjords. We neglect a horizontal momentum of the plume and assume that its influence on the plume dynamics is small and important only close to the source. Moreover, idealized models have considered the plume adjacent to the glacier as a half-conical plume (e.g., [1]). Thus, to compare the results for such plume with the classical plume theory, developed for free plumes entraining ambient fluid from all directions, it is convenient to add the second half-conical part and consider a free plume with double the total discharge as a model. Given the estimate of the total subglacial discharge for Helheim Glacier in Sermilik Fjord [2], we perform simulations with double the total discharge in order to investigate the dynamics of the flow in typical winter and summer stratifications in Greenland fjords [3]. The plume is discharged from a round source of various diameters. In winter, when the stratification is similar to an idealised two-layers case, turbulent entrainment and generation of internal waves by the plume top are in agreement with the theoretical and numerical results obtained for turbulent jets in a two-layer stratification. In summer, instead, the stratification is more complex and turbulent entrainment is significantly reduced. The subsurface layer in summer is characterized by a strong density gradient and the oscillating plume generates non-linear internal waves which are able to mix this layer even if the plume does not penetrate to the surface. The classical theory for the integral parameters of a turbulent plume in a homogeneous fluid gives accurate predictions of the plume parameters in the weakly stratified lower layer up to the pycnocline. [1] Mankoff, K. D., F. Straneo, C. Cenedese, S. B. Das, C. D. Richards, and H. Singh, 2016: Structure

Deep learning in pharmacogenomics: from gene regulation to patient stratification.

PubMed

Kalinin, Alexandr A; Higgins, Gerald A; Reamaroon, Narathip; Soroushmehr, Sayedmohammadreza; Allyn-Feuer, Ari; Dinov, Ivo D; Najarian, Kayvan; Athey, Brian D

2018-05-01

This Perspective provides examples of current and future applications of deep learning in pharmacogenomics, including: identification of novel regulatory variants located in noncoding domains of the genome and their function as applied to pharmacoepigenomics; patient stratification from medical records; and the mechanistic prediction of drug response, targets and their interactions. Deep learning encapsulates a family of machine learning algorithms that has transformed many important subfields of artificial intelligence over the last decade, and has demonstrated breakthrough performance improvements on a wide range of tasks in biomedicine. We anticipate that in the future, deep learning will be widely used to predict personalized drug response and optimize medication selection and dosing, using knowledge extracted from large and complex molecular, epidemiological, clinical and demographic datasets.

Novel Molecular Imaging Approaches to Abdominal Aortic Aneurysm Risk Stratification

PubMed Central

Toczek, Jakub; Meadows, Judith L.; Sadeghi, Mehran M.

2015-01-01

Selection of patients for abdominal aortic aneurysm (AAA) repair is currently based on aneurysm size, growth rate and symptoms. Molecular imaging of biological processes associated with aneurysm growth and rupture, e.g., inflammation and matrix remodeling, could improve patient risk stratification and lead to a reduction in AAA morbidity and mortality. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and ultrasmall superparamagnetic particles of iron oxide (USPIO) magnetic resonance imaging are two novel approaches to AAA imaging evaluated in clinical trials. A variety of other tracers, including those that target inflammatory cells and proteolytic enzymes (e.g., integrin αvβ3 and matrix metalloproteinases), have proven effective in preclinical models of AAA and show great potential for clinical translation. PMID:26763279

Une colite à CMV révélant un lupus érythémateux systémique

PubMed Central

Ben Ghorbel, Imed; Boussetta, Najeh; Boubaker, Jalel; Zehani, Alia; Lamloum, Mounir; Houman, Mohamed Habib

2014-01-01

Le cytomégalovirus (CMV) est responsable d'infections souvent asymptomatiques chez les immunocompétents mais également d'infections graves chez les immunodéprimés notamment chez les patients lupiques. La réactivation du CMV au cours du lupus est une complication fréquente mais rarement inaugurale. Nous rapportons l'observation d'un patient ayant présenté une colite à CMV révélatrice d'un lupus érythémateux systémique. Le diagnostic a été retenu sur les données sérologiques, de la biopsie colique et la bonne évolution après un traitement par ganciclovir. PMID:25977743

La prévention des blessures chez les enfants et les adolescents : une démarche de santé publique

PubMed Central

Yanchar, Natalie L; Warda, Lynne J; Fuselli, Pamela

2012-01-01

RÉSUMÉ La majorité des blessures dont sont victimes les enfants et les adolescents sont évitables. Le présent document de principes contient des renseignements généraux, des conseils et une déclaration d’engagement à l’égard de la prévention des blessures au Canada. Il sert de base sur laquelle construire en s’attardant d’abord aux définitions, à l’étendue et aux priorités en matière de prévention des blessures. Il contient également une description du fardeau et du profil des blessures non intentionnelles, de même que les principes d’interventions de prévention efficaces. La version intégrale renferme une liste de ressources en vue d’obtenir des données et de l’information probante (www.cps.ca). Enfin, le présent document de principes peut être utilisé pour la défense généralisée de la prévention des blessures.

Finite element solution to passive scalar transport behind line sources under neutral and unstable stratification

NASA Astrophysics Data System (ADS)

Liu, Chun-Ho; Leung, Dennis Y. C.

2006-02-01

This study employed a direct numerical simulation (DNS) technique to contrast the plume behaviours and mixing of passive scalar emitted from line sources (aligned with the spanwise direction) in neutrally and unstably stratified open-channel flows. The DNS model was developed using the Galerkin finite element method (FEM) employing trilinear brick elements with equal-order interpolating polynomials that solved the momentum and continuity equations, together with conservation of energy and mass equations in incompressible flow. The second-order accurate fractional-step method was used to handle the implicit velocity-pressure coupling in incompressible flow. It also segregated the solution to the advection and diffusion terms, which were then integrated in time, respectively, by the explicit third-order accurate Runge-Kutta method and the implicit second-order accurate Crank-Nicolson method. The buoyancy term under unstable stratification was integrated in time explicitly by the first-order accurate Euler method. The DNS FEM model calculated the scalar-plume development and the mean plume path. In particular, it calculated the plume meandering in the wall-normal direction under unstable stratification that agreed well with the laboratory and field measurements, as well as previous modelling results available in literature.

The evolving field of prognostication and risk stratification in MDS: Recent developments and future directions.

PubMed

Lee, Eun-Ju; Podoltsev, Nikolai; Gore, Steven D; Zeidan, Amer M

2016-01-01

The clinical course of patients with myelodysplastic syndromes (MDS) is characterized by wide variability reflecting the underlying genetic and biological heterogeneity of the disease. Accurate prediction of outcomes for individual patients is an integral part of the evidence-based risk/benefit calculations that are necessary for tailoring the aggressiveness of therapeutic interventions. While several prognostication tools have been developed and validated for risk stratification, each of these systems has limitations. The recent progress in genomic sequencing techniques has led to discoveries of recurrent molecular mutations in MDS patients with independent impact on relevant clinical outcomes. Reliable assays of these mutations have already entered the clinic and efforts are currently ongoing to formally incorporate mutational analysis into the existing clinicopathologic risk stratification tools. Additionally, mutational analysis holds promise for going beyond prognostication to therapeutic selection and individualized treatment-specific prediction of outcomes; abilities that would revolutionize MDS patient care. Despite these exciting developments, the best way of incorporating molecular testing for use in prognostication and prediction of outcomes in clinical practice remains undefined and further research is warranted. Copyright © 2015 Elsevier Ltd. All rights reserved.

From institutional segmentation to market fragmentation: Institutional transformation and the shifting stratification order in urban China.

PubMed

Zhao, Wei; Zhou, Xueguang

2017-03-01

Focusing on the changing roles of organizations, this study develops an institutional framework to examine the shifting stratification order since the mid-1990s in urban China. We argue that, after the mid-1990s, the Chinese state led a dual process of institutional transformation. On the one hand, the state dismantled the socialist redistributive system and broke down institutional segmentation based on organizational ownership and bureaucratic rank. On the other hand, the state developed different markets with various paces and strategies, resulting in fragmented market environments. In this context, reformed organizations interacted with heterogeneous market conditions to exert different impacts on multiple dimensions of social inequality. We draw empirical evidence from two national survey data collected in 1994 and 2003 during a critical period. Our findings show that the foundation of the stratification order has shifted from institutional segmentation to market fragmentation in urban China. This study calls for substantive institutional analysis to better understand the intricate landscape of social inequality in transitional economies. Copyright © 2016 Elsevier Inc. All rights reserved.

Microbial stratification structure within cathodic biofilm of the microbial fuel cell using the freezing microtome method.

PubMed

Li, Xiao; Lu, Yaobin; Luo, Haiping; Liu, Guangli; Zhang, Renduo

2017-10-01

The aim of this study was to investigate the microbial stratification structure within cathodic biofilm of the microbial fuel cell (MFC) using the freezing microtome method. Experiments were conducted in a single-chamber air-cathode MFC with 0.8g/L maltodextrin as substrate for ∼30d operation. The maximum power density was 945±10mW/m 2 in the MFC. Maltodextrin resulted in the relative abundance of Candidatus Saccharibacteria of 37.0% in the anodic biofilm. Different bacterial communities were identified in different layers within the cathodic biofilm. The relative abundance of Enterococcus was 3.7%, 10.5%, and 1.6% in the top (100-150μm), middle (50-100μm), and bottom (0-50μm) layers, respectively. Higher bacterial viability was observed within the top and bottom layers of the cathodic biofilm. Understanding the stratification of bacterial community in cathodic biofilm should be important to control the cathodic biofilm in the MFC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Étalement d'une goutte stratifiée incompressible

NASA Astrophysics Data System (ADS)

de Gennes, Pierre-Gilles; Cazabat, Anne-Marie

L'étalement de films ultraminces de liquides simples sur une surface lisse horizontale conduit souvent à des gouttes à gradins d'une épaisseur moléculaire ([1]-[3]). Nous construisons ici un modèle pour la dynamique de l'étalement, en supposant que : (a) chaque gradin est un liquide bidimensionnel incompressible; (b) les molécules de la n-ième couche sont soumises à un potentiel (Wn) qui exprime leurs interactions à longue portée avec le solide; (c) on a un écoulement parallèle de cisaillement, et un écoulement normal de perméation. La perméation intervient seulement dans un certain « ruban » de largeur ξ sur le bord de chaque gradin. Dans le cas usuel, où le rayon du n-ième gradin Rn est trs supérieur à ξ, la dissipation est dominée par le cisaillement, et on arrive à des lois simples pour la vitesse de dilatation (ou de contraction) dotR_n. Very thin films of simple liquids often spread with well defined steps of molecular thickness ([1]-[3]). We construct a model for the dynamics of spreading assuming that: (a) each layer is an incompressible, 2 dimensional fluid; (b) the molecules in the (nth) layer experience a long range potential (e.g. Van der Waals) from the solid; (c) two types of flow occur: shear between layers and permeation normal to the layers. We find that permeation is important only in an annulus of small size ξ near each step. Between steps, the viscous effects in simple shear dominate, and this leads to simple laws for the dilation (or contraction) of the various layers.

Approche au diagnostic de la maladie cœliaque chez les patients ayant une faible densité minérale osseuse ou des fractures de fragilité

PubMed Central

Rios, Lorena P.; Khan, Aliya; Sultan, Muhammad; McAssey, Karen; Fouda, Mona A.; Armstrong, David

2013-01-01

Résumé Objectif Présenter aux cliniciens une mise à jour sur le diagnostic de la maladie cœliaque (MC), ainsi que des recommandations sur les indications de procéder au dépistage de la MC chez les patients présentant une faible densité minérale osseuse (DMO) ou des fractures de fragilité. Qualité des données Un groupe de travail multidisciplinaire a élaboré des questions cliniquement pertinentes relativement au diagnostic de la MC servant de fondement à une recherche documentaire dans les bases de données MEDLINE, EMBASE et CENTRAL (de janvier 2000 à janvier 2009) à l’aide des mots clés en anglais celiac disease, osteoporosis, osteopenia, low bone mass et fracture. Les ouvrages scientifiques existants comportent des études de niveaux I et II. Message principal La prévalence estimée de la MC asymptomatique est de 2 % à 3 % chez les personnes qui ont une faible DMO. Par ailleurs, un dépistage ciblé est recommandé pour les patients qui ont des T-scores de −1,0 ou moins à la colonne vertébrale ou aux hanches ou des antécédents de fractures de fragilité associées à des symptômes ou à des problèmes reliés à la MC, des antécédents familiaux de MC ou de bas niveaux de calcium urinaire, une insuffisance en vitamine D et des niveaux à la hausse d’hormones parathyroïdiennes en dépit d’un apport suffisant en calcium et en vitamine D. Le dépistage de la MC devrait se faire pendant que le sujet consomme un régime alimentaire contenant du gluten. On procède au dépistage initial par le dosage d’immunoglobuline (Ig) A antitransglutaminase en utilisant la transglutaminase tissulaire humaine recombinante ou une autre transglutaminase tissulaire, en association avec l’immunofluorescence des IgA anti-endomysium. Une biopsie du duodénum est nécessaire pour confirmer le diagnostic de la MC. Le typage des antigènes des leucocytes humains peut aider à confirmer ou à exclure le diagnostic de la MC dans les cas où la s

Analysis of agreement between cardiac risk stratification protocols applied to participants of a center for cardiac rehabilitation

PubMed Central

Santos, Ana A. S.; Silva, Anne K. F.; Vanderlei, Franciele M.; Christofaro, Diego G. D.; Gonçalves, Aline F. L.; Vanderlei, Luiz C. M.

2016-01-01

ABSTRACT Background Cardiac risk stratification is related to the risk of the occurrence of events induced by exercise. Despite the existence of several protocols to calculate risk stratification, studies indicating that there is similarity between these protocols are still unknown. Objective To evaluate the agreement between the existing protocols on cardiac risk rating in cardiac patients. Method The records of 50 patients from a cardiac rehabilitation program were analyzed, from which the following information was extracted: age, sex, weight, height, clinical diagnosis, medical history, risk factors, associated diseases, and the results from the most recent laboratory and complementary tests performed. This information was used for risk stratification of the patients in the protocols of the American College of Sports Medicine, the Brazilian Society of Cardiology, the American Heart Association, the protocol designed by Frederic J. Pashkow, the American Association of Cardiovascular and Pulmonary Rehabilitation, the Société Française de Cardiologie, and the Sociedad Española de Cardiología. Descriptive statistics were used to characterize the sample and the analysis of agreement between the protocols was calculated using the Kappa coefficient. Differences were considered with a significance level of 5%. Results Of the 21 analyses of agreement, 12 were considered significant between the protocols used for risk classification, with nine classified as moderate and three as low. No agreements were classified as excellent. Different proportions were observed in each risk category, with significant differences between the protocols for all risk categories. Conclusion The agreements between the protocols were considered low and moderate and the risk proportions differed between protocols. PMID:27556385

Continental Shelf Embayments of the Eastern Margin of the Philippines: Lamon Bay Stratification and Circulation

DTIC Science & Technology

2013-09-30

Philippines; Lamon Bay Stratification & Circulation Arnold L. Gordon Lamont-Doherty Earth Observatory 61 Route 9W Palisades , NY 10964-8000...Route 9W, Palisades ,NY,10964-8000 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR...dipole circulation cell is separated from a cyclonic dipole of the southwest Lamon Bay by a flow towards the northwest, which feeds into the

Comparison of estimation techniques for a forest inventory in which double sampling for stratification is used

Treesearch

Michael S. Williams

2001-01-01

A number of different estimators can be used when forest inventory plots cover two or more distinctly different condition classes. In this article the properties of two approximate Horvitz- Thompson (HT) estimators, a ratio of means (RM), and a mean of ratios (MR) estimator are explored in the framework of double sampling for stratification. Relevant theoretical...

Une présentation atypique de la maladie cœliaque: l'occlusion de la veine centrale de la rétine

PubMed Central

Jomni, Taieb; Bellakhal, Syrine; Abouda, Maher; Abdelaali, Imene; Douggui, Hédi

2015-01-01

Parmi les complications thrombotiques de la maladie cœliaque l'occlusion de la veine centrale de la rétine a été exceptionnellement décrite. Nous rapportons l'observation d'une patiente âgée de 27 ans chez qui le diagnostic de maladie cœliaque a été porté dans le cadre du bilan étiologique d'une occlusion de la veine centrale de la rétine. L'interrogatoire ne révélait pas de diarrhée chronique ou de douleurs abdominales. La présence d'un amaigrissement, d'une anémie ferriprive et d'une hypocholestérolémie ont permis l'orientation vers la maladie cœliaque. La positivité des anticorps anti endomysium et la biopsie duodénale montrant l'atrophie villositaire confirmaient ce diagnostic. Le régime sans gluten associé à un traitement par aspirine avait partiellement amélioré l'acuité visuelle chez notre patiente. Cette présentation atypique de la maladie cœliaque souligne la diversité des manifestations extra-digestives au cours de cette maladie et l'intérêt de penser à la maladie cœliaque même lorsque ces manifestations sont inaugurales. PMID:26966496

Relating sedimentary processes in the Bagnold Dunes to the development of crater basin aeolian stratification

NASA Astrophysics Data System (ADS)

Ewing, R. C.; Lapotre, M. G. A.; Lewis, K. W.; Day, M. D.; Stein, N.; Rubin, D. M.; Sullivan, R. J., Jr.; Banham, S.; Thomas, N. M.; Lamb, M. P.; Gupta, S.; Fischer, W. W.

2017-12-01

Wind-blown sand dunes are ubiquitous on the surface of Mars and are a recognized component of the martian stratigraphic record. Our current knowledge of the aeolian sedimentary processes that determine dune morphology, drive dune dynamics, and create aeolian cross-stratification are based upon orbital studies of ripple and dune morphodynamics, rover observations of stratification on Mars, Earth analogs, and experimental and theoretical studies of sand movement under martian conditions. Exploration of the Bagnold Dunes by the Curiosity Rover in Gale Crater, Mars provided the first opportunity to make in situ observations of martian dunes from the grain-to-dune scale. We used the suite of cameras on Curiosity, including Navigation Camera, Mast Camera, and Mars Hand Lens Imager. We measured grainsize and identified sedimentary processes similar to processes on terrestrial dunes, such as grainfall, grainflow, and impact ripples. Impact ripple grainsize had a median of 0.103 mm. Measurements of grainflow slopes indicate a relaxation angle of 29° and grainfall slopes indicate critical angles of at least 32°. Dissimilar to terrestrial dunes, large, meter-scale ripples form on all slopes of the dunes. The ripples form both sinuous and linear crestlines, have symmetric and asymmetric profiles, range in height between 12cm and 28cm, and host grainfall, grainflow, and impact ripples. The largest ripples are interpreted to integrate the annual wind cycle within the crater, whereas smaller large ripples and impact ripples form or reorient to shorter term wind cycling. Assessment of sedimentary processes in combination with dune type across the Bagnold Dunes shows that dune-field pattern development in response to a complex crater-basin wind regime dictates the distribution of geomorphic processes. From a stratigraphic perspective, zones of highest potential accumulation correlate with zones of wind convergence, which produce complex winds and dune field patterns thereby

Feeding height stratification among the herbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada

PubMed Central

2013-01-01

Background Herbivore coexistence on the Late Cretaceous island continent of Laramidia has been a topic of great interest, stemming from the paradoxically high diversity and biomass of these animals in relation to the relatively small landmass available to them. Various hypotheses have been advanced to account for these facts, of which niche partitioning is among the most frequently invoked. However, despite its wide acceptance, this hypothesis has not been rigorously tested. This study uses the fossil assemblage from the Dinosaur Park Formation of Alberta as a model to investigate whether niche partitioning facilitated herbivorous dinosaur coexistence on Laramidia. Specifically, the question of feeding height stratification is examined in light of the role it plays in facilitating modern ungulate coexistence. Results Most herbivorous dinosaur species from the Dinosaur Park Formation were restricted to feeding no higher than approximately 1 m above the ground. There is minimal evidence for feeding height partitioning at this level, with ceratopsids capable of feeding slightly higher than ankylosaurs, but the ecological significance of this is ambiguous. Hadrosaurids were uniquely capable of feeding up to 2 m quadrupedally, or up to 5 m bipedally. There is no evidence for either feeding height stratification within any of these clades, or for change in these ecological relationships through the approximately 1.5 Ma record of the Dinosaur Park Formation. Conclusions Although we cannot reject the possibility, we find no good evidence that feeding height stratification, as revealed by reconstructed maximum feeding heights, played an important role in facilitating niche partitioning among the herbivorous dinosaurs of Laramidia. Most browsing pressure was concentrated in the herb layer, although hadrosaurids were capable of reaching shrubs and low-growing trees that were out of reach from ceratopsids, ankylosaurs, and other small herbivores, effectively dividing the

Feeding height stratification among the herbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada.

PubMed

Mallon, Jordan C; Evans, David C; Ryan, Michael J; Anderson, Jason S

2013-04-04

Herbivore coexistence on the Late Cretaceous island continent of Laramidia has been a topic of great interest, stemming from the paradoxically high diversity and biomass of these animals in relation to the relatively small landmass available to them. Various hypotheses have been advanced to account for these facts, of which niche partitioning is among the most frequently invoked. However, despite its wide acceptance, this hypothesis has not been rigorously tested. This study uses the fossil assemblage from the Dinosaur Park Formation of Alberta as a model to investigate whether niche partitioning facilitated herbivorous dinosaur coexistence on Laramidia. Specifically, the question of feeding height stratification is examined in light of the role it plays in facilitating modern ungulate coexistence. Most herbivorous dinosaur species from the Dinosaur Park Formation were restricted to feeding no higher than approximately 1 m above the ground. There is minimal evidence for feeding height partitioning at this level, with ceratopsids capable of feeding slightly higher than ankylosaurs, but the ecological significance of this is ambiguous. Hadrosaurids were uniquely capable of feeding up to 2 m quadrupedally, or up to 5 m bipedally. There is no evidence for either feeding height stratification within any of these clades, or for change in these ecological relationships through the approximately 1.5 Ma record of the Dinosaur Park Formation. Although we cannot reject the possibility, we find no good evidence that feeding height stratification, as revealed by reconstructed maximum feeding heights, played an important role in facilitating niche partitioning among the herbivorous dinosaurs of Laramidia. Most browsing pressure was concentrated in the herb layer, although hadrosaurids were capable of reaching shrubs and low-growing trees that were out of reach from ceratopsids, ankylosaurs, and other small herbivores, effectively dividing the herbivores in terms of relative

Risk stratification using SpO2/FiO2 and PEEP at initial ARDS diagnosis and after 24 h in patients with moderate or severe ARDS.

PubMed

Pisani, Luigi; Roozeman, Jan-Paul; Simonis, Fabienne D; Giangregorio, Antonio; van der Hoeven, Sophia M; Schouten, Laura R; Horn, Janneke; Neto, Ary Serpa; Festic, Emir; Dondorp, Arjen M; Grasso, Salvatore; Bos, Lieuwe D; Schultz, Marcus J

2017-10-25

We assessed the potential of risk stratification of ARDS patients using SpO 2 /FiO 2 and positive end-expiratory pressure (PEEP) at ARDS onset and after 24 h. We used data from a prospective observational study in patients admitted to a mixed medical-surgical intensive care unit of a university hospital in the Netherlands. Risk stratification was by cutoffs for SpO 2 /FiO 2 and PEEP. The primary outcome was in-hospital mortality. Patients with moderate or severe ARDS with a length of stay of > 24 h were included in this study. Patients were assigned to four predefined risk groups: group I (SpO 2 /FiO 2  ≥ 190 and PEEP < 10 cm H 2 O), group II (SpO 2 /FiO 2  ≥ 190 and PEEP ≥ 10 cm), group III (SpO 2 /FiO 2  < 190 and PEEP < 10 cm H 2 O) and group IV (SpO 2 /FiO 2  < 190 and PEEP ≥ 10 cm H 2 O). The analysis included 456 patients. SpO 2 /FiO 2 and PaO 2 /FiO 2 had a strong relationship (P < 0.001, R 2  = 0.676) that could be described in a linear regression equation (SpO 2 /FiO 2  = 42.6 + 1.0 * PaO 2 /FiO 2 ). Risk stratification at initial ARDS diagnosis resulted in groups that had no differences in in-hospital mortality. Risk stratification at 24 h resulted in groups with increasing mortality rates. The association between group assignment at 24 h and outcome was confounded by several factors, including APACHE IV scores, arterial pH and plasma lactate levels, and vasopressor therapy. In this cohort of patients with moderate or severe ARDS, SpO 2 /FiO 2 and PaO 2 /FiO 2 have a strong linear relationship. In contrast to risk stratification at initial ARDS diagnosis, risk stratification using SpO 2 /FiO 2 and PEEP after 24 h resulted in groups with worsening outcomes. Risk stratification using SpO 2 /FiO 2 and PEEP could be practical, especially in resource-limited settings.

Vertical stratification of forest canopy for segmentation of understory trees within small-footprint airborne LiDAR point clouds

NASA Astrophysics Data System (ADS)

Hamraz, Hamid; Contreras, Marco A.; Zhang, Jun

2017-08-01

Airborne LiDAR point cloud representing a forest contains 3D data, from which vertical stand structure even of understory layers can be derived. This paper presents a tree segmentation approach for multi-story stands that stratifies the point cloud to canopy layers and segments individual tree crowns within each layer using a digital surface model based tree segmentation method. The novelty of the approach is the stratification procedure that separates the point cloud to an overstory and multiple understory tree canopy layers by analyzing vertical distributions of LiDAR points within overlapping locales. The procedure does not make a priori assumptions about the shape and size of the tree crowns and can, independent of the tree segmentation method, be utilized to vertically stratify tree crowns of forest canopies. We applied the proposed approach to the University of Kentucky Robinson Forest - a natural deciduous forest with complex and highly variable terrain and vegetation structure. The segmentation results showed that using the stratification procedure strongly improved detecting understory trees (from 46% to 68%) at the cost of introducing a fair number of over-segmented understory trees (increased from 1% to 16%), while barely affecting the overall segmentation quality of overstory trees. Results of vertical stratification of the canopy showed that the point density of understory canopy layers were suboptimal for performing a reasonable tree segmentation, suggesting that acquiring denser LiDAR point clouds would allow more improvements in segmenting understory trees. As shown by inspecting correlations of the results with forest structure, the segmentation approach is applicable to a variety of forest types.