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Journal articles on the topic 'Failles normales'
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Ngindu Buabua, David. "Rift Upemba et tectonique." Revue Congolaise des Sciences & Technologies 2, no. 2 (June 23, 2023): 289–95. http://dx.doi.org/10.59228/rcst.023.v2.i2.31.
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Dans ce travail nous allons examiner l’évolution du Rift Upemba par rapport à la tectonique de la région et conclure sur les alignements des failles dans le Rift. Les méthodes utilisées pour cette étude comprennent la télédétection et le traitement par Système d’Information Géographique, grâce au logiciel ArcGIS 10.8. Comme résultats, le Rift Upemba, par rapport à la tectonique de la région, n’est pas constitué d’une seule faille en segment de droite mais de deux failles normales composées situées de part et d’autre du Rift dans la dépression délimitée par des lacs. D’où, le Rift Upemba est considéré comme un rift avorté car son mouvement d’extension s’est arrêté il y a plusieurs années. Mots clés: Rift, Upemba, tectonique, télédétection, failles.
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Ngindu Buabua, David. "Rift Upemba et tectonique." Revue Congolaise des Sciences & Technologies 02, no. 02 (June 24, 2023): 289–95. http://dx.doi.org/10.59228/rcst.023.v2.i1.31.
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Dans ce travail nous allons examiner l’évolution du Rift Upemba par rapport à la tectonique de la région et conclure sur les alignements des failles dans le Rift. Les méthodes utilisées pour cette étude comprennent la télédétection et le traitement par Système d’Information Géographique, grâce au logiciel ArcGIS 10.8. Comme résultats, le Rift Upemba, par rapport à la tectonique de la région, n’est pas constitué d’une seule faille en segment de droite mais de deux failles normales composées situées de part et d’autre du Rift dans la dépression délimitée par des lacs. D’où, le Rift Upemba est considéré comme un rift avorté car son mouvement d’extension s’est arrêté il y a plusieurs années. Mots clés: Rift, Upemba, tectonique, télédétection, failles.
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Meyer, B., J. P. Avouac, P. Tapponnier, and M. Meghraoui. "Mesures topographiques sur le segment SW de la zone faillee d'El Asnam et interpretation mecanique des relations entre failles inverses et normales." Bulletin de la Société Géologique de France VI, no. 3 (May 1, 1990): 447–56. http://dx.doi.org/10.2113/gssgfbull.vi.3.447.
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Hervouët, Yves, Nicolas Espurt, and Damien Dhont. "Failles normales Paléocène à Lutétien en zone sud-pyrénéenne (Aragon, Espagne) et flexuration de la plaque ibérique." Comptes Rendus Geoscience 337, no. 3 (February 2005): 385–92. http://dx.doi.org/10.1016/j.crte.2004.11.001.
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Graveleau, Fabien, Frank Chanier, Francis Meilliez, Jean-Yves Reynaud, and Geoffray Musial. "Observation de la surface de transgression du tuffeau thanétien sur la craie coniacienne au niveau du flanc nord de l'anticlinal du Mélantois (Nord)." Annales de la Société géologique du Nord - (2e Série), Tome 28, no. 28 (December 1, 2021): 99–110. http://dx.doi.org/10.54563/asgn.321.
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Le suivi régulier d’un chantier de terrassement localisé à la limite des communes de Lezennes et de Villeneuve d’Ascq, au cœur de la Métropole de Lille (59, Nord), a permis d’observer et d’analyser en détail le contact géologique entre le « tuffeau » du Thanétien et la craie du Coniacien. Cette surface de contact apparaît remarquablement nette et plane, sub-horizontale et faiblement déformée. Quelques failles normales (N100-110) et décrochantes (N-S) la fracturent avec des rejets verticaux décimétriques à métriques. Cette surface est marquée par la présence d’un impressionnant réseau de terriers fossiles de type Thalassinoides isp creusés dans la craie, à remplissage thanétien et caractéristiques de l’ichnofaciès à Glossifungites. L’interprétation de cet ichnofaciès soulève de nombreux questionnements sur leur origine que de futures études de sédimentologie et de micropaléontologie devraient permettre de lever, renseignant ainsi l’histoire géologique de la transgression paléocène dans le Nord de la France.
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Moulouel, Hakim, Luca Micarelli, Isabelle Moretti, and Djamel Machane. "Fracturation des carbonates dans la zone de faille normale active d’Aigion (Grèce) à partir des carottes du puits: conséquences sur les propriétés de transfert de fluides." Bulletin de la Société Géologique de France 186, no. 6 (October 1, 2015): 387–97. http://dx.doi.org/10.2113/gssgfbull.186.6.387.
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Abstract La faille d’Aigion appartient à un système de failles normales à pendage nord affectant la bordure sud du golfe de Corinthe, témoin d’une extension active d’échelle régionale caractérisant la région égéenne. Les carottes du forage AIG-10, qui a traversé cette faille, montrent la présence d’une zone endommagée et d’une gouge. Ce travail présente une analyse des lames minces faites à partir de ces carottes. Il confirme la zonation en termes de fracturation à l’approche de la faille. Loin de cette dernière, la fracturation héritée de la phase compressive de l’orogenèse hellénique est dominante, bien qu’il existe aussi une famille E-W liée à l’extension actuelle. Toutes ces fractures sont scellées et le remplissage est similaire d’un point de vue luminescence au calcaire hôte. A l’approche du coeur, la quantité de fractures liées à la faille augmente; le remplissage de ces fractures indique, en cathodoluminescence, le passage de plusieurs fluides qui seraient d’origine externe, et la dernière génération de fractures est encore ouverte. Au mur de la faille, sous 5 m d’épaisseur verticale de cataclasite et d’ultracataclasite dans les calcaires et radiolarites (coeur de faille) et 13 m d’épaisseur verticale de gouge dans les radiolarites, les observations sont plus limitées, car la présence d’un karst a restreint les possibilités de carottage. Néanmoins, on peut observer que le remplissage des fractures liées à l’extension est différent de ce qui nous a été dévoilé au toit. Ceci suggère que la faille, transversalement imperméable aujourd’hui, l’a toujours été. L’analyse de la succession des ciments met en évidence une perméabilité parallèle à la faille à la faveur d’un système de fractures et fentes jeunes et ouvertes, pendant qu’est discuté le transfert de fluides par rapport aux stades de propagation de la faille.
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Ferrière, Jacky, and Frank Chanier. "La marge Ouest-Maliaque de la Téthys (Hellénides) : une marge en hyper-extension, pauvre en magma." Annales de la Société géologique du Nord - (2e Série), Tome 28, no. 28 (December 1, 2021): 39–56. http://dx.doi.org/10.54563/asgn.288.
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La reconstitution des marges passives anciennes à partir de l’étude d’affleurements à terre se heurte au problème de la déformation des séries issues de la marge, en raison de leur mise en place tectonique sur les domaines continentaux. Dans le massif de l’Othrys, en Grèce, les témoins d’une marge téthysienne (Océan Maliaque) sont correctement préservés au sein de nappes syn-obduction du Jurassique. Dans ce massif, ces nappes sont nombreuses : 3 nappes ophiolitiques et 6 nappes issues de la marge. L’empilement des nappes est régulier : les nappes possédant des séries de forte profondeur (séries distales) recouvrent toujours des unités comportant des séries de moindre profondeur (proximales). Il est ainsi possible de reconstituer la marge Ouest-Maliaque de façon assez complète et relativement fiable. Des travaux antérieurs, notamment par les auteurs de ce travail, ont permis d’établir les grandes lignes de cette reconstitution.De nouveaux résultats sur la série d’Othrys, confrontés aux données sur les marges actuelles permettent d’observer que la marge Ouest-Maliaque se rapproche des marges en « hyper- extension » relativement pauvres en magma. Ces résultats permettent également une analyse des mécanismes de déformation syn-rift (Trias moyen) de la marge Ouest-Maliaque, qu’il s’agisse des différentes phases de déformation successives, ou des différents ensembles résultants de ces déformations. Les différentes phases de déformation typiques d’un rift se succèdent, avec (1) une déformation diffuse avec le développement de failles normales dans la croûte continentale supérieure cassante (stretching) ; (2) une déformation plus localisée (thinning) à l’origine de la marge distale ; (3) une possible exhumation de manteau sous-continental et (4) l’accrétion océanique (fin du Rifting) dès l’Anisien supérieur. Cette déformation s’exprime par la présence de différents domaines structuraux à travers la marge : (1) le domaine de necking, transition entre le bloc continental à croûte épaisse (environ 30 km) et la marge distale à croûte très amincie (environ 10 km) ; (2) la marge distale issue du fonctionnement d’une « faille de détachement » ; (3) un bloc distal, haut-fond transitoire, au contact de la croûte océanique et/ou, localement, de manteau continental exhumé partiellement serpentinisé. Dans certains cas, l’exhumation de manteau hydraté au sein même de la marge distale sous l’effet de l’hyper-extension isole des blocs distaux parfois nommés « extensional allochtons ».
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Ferrière, Jacky, and Frank Chanier. "Analysis of an obduction process: the example of the Tethyan Maliac Ocean (Hellenides)." Annales de la Société Géologique du Nord, no. 27 (December 2, 2020): 37–54. http://dx.doi.org/10.54563/asgn.254.
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L’obduction, charriage de la lithosphère océanique sur la croûte continentale, à l’origine des ophiolites, a été défini suite à la révolution de la tectonique des plaques. Dans un premier temps, les analyses ont surtout porté sur la pétrographie et la géochimie des ensembles ophiolitiques (par ex. Vourinos en Grèce, Troodos à Chypre, nappe du Semail en Oman). Notre étude concerne principalement un secteur des Hellénides, le massif de l’Othrys, où l’on peut observer un système ophiolitique complet représenté par un empilement de nappes mises en place pendant l’obduction de l’Océan téthysien Maliaque. L’existence d’une couverture crétacée discordante sur ces nappes, permet de les attribuer, sans équivoque, au processus d’obduction du Jurassique moyen-supérieur. Le dispositif structural est constitué de trois nappes ophiolitiques recouvrant un ensemble de cinq autres nappes correspondant à l’écaillage de la marge continentale sous ces nappes ophiolitiques. Dans ce massif, les ophiolites datées du Jurassique moyen (Mega Isoma et Metalleion) présentent des caractéristiques en partie comparables (répartition, nature pétrographique, âge) à celles des ophiolites du Vourinos-Pinde du Nord, supposées être nées au sein de la plaque supérieure d’une zone de subduction. En revanche, nous avons pu mettre en évidence, en Othrys, des nappes originales : i) une nappe ophiolitique de pillow-lavas du Trias (Fourka, de type MORB) témoin de la période initiale de l’océan ; ii) des nappes issues de la marge distale permettant de reconstituer précisément cette marge. L’analyse de ces différentes nappes nous a permis de reconnaître ou de préciser certaines modalités du processus d’obduction : i) la mise en place tectonique d’une unité (Fourka) appartenant à la plaque plongeante au niveau d’une subduction (et non pas à la plaque supérieure) ; ii) la genèse de certaines nappes à partir de failles normales listriques liées au rifting triasique (processus d’inversion tectonique positive) ; iii) les modalités de déplacement des nappes sur le domaine continental (marge et plate-forme) par l’analyse des mélanges à blocs nés à l’avant des nappes. Deux événements tardi-obduction ont également été étudiés : la genèse d’un bassin d’avant-chaîne et le développement de fenêtres tectoniques au cœur des nappes.
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Schoonmaker, Adam, William S. F. Kidd, Stephen E. DeLong, and John F. Bender. "Lawrence Head Volcanics and Dunnage Mélange, Newfoundland Appalachians: Origin by Ordovician Ridge Subduction or in Back-Arc Rift?" Geoscience Canada 41, no. 4 (December 3, 2014): 523. http://dx.doi.org/10.12789/geocanj.2014.41.053.
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This paper reviews the geological setting and reports new geochemical trace element data from the Ordovician Lawrence Head Volcanics (LHV) and the underlying gabbro sills in the Exploits Group. In combination with existing published analyses and ages of these rocks, the volcanic rocks and sills are indistinguishable in composition and age, and the data are consistent with the hypothesis that they represent the same (mostly E-MORB composition) magmatic event in the early–mid Darriwilian (~465 ± 2 Ma). The LHV and their enclosing strata show regional evidence for: 1) upward decline of volume and grain size of arc-derived volcaniclastic materials over the uppermost interval of turbidite sedimentary strata below the LHV; 2) change to shallow marine conditions locally by the end of the LHV event, followed immediately by significant subsidence, and 3) no evidence of coarse-grained clastic input, nor of normal faulting, during or immediately after LHV magmatism. Ridge–trench interaction (ridge subduction) at a subduction system is consistent with all of these features and spatial distribution of related elements, but a rift (back-arc) origin over a subduction zone can only accommodate the compositions, and is inconsistent with the geological evidence. The Dunnage Mélange (DM) has been interpreted either as olistostromal in a developing back-arc rift basin, or as a subduction accretionary prism. Peraluminous intrusions in the mélange (Coaker Porphyry ― CP) are more readily explained by ridge subduction, and a previously reported zircon age (469 ± 4 Ma) is consistent with the age of the LHV and gabbro sills, also interpreted as products of ridge subduction. Localization of the CP in the eastern area of DM, and of most of the large LHV-derived volcanic blocks in the western DM, suggests a slightly younger age, and perhaps a different mechanism, for the origin of the western DM.SOMMAIRECet article passe en revue le contexte géologique et présente de nouvelles données géochimiques d’éléments traces des roches volcaniques ordoviciennes de Lawrence Head (LHV) et des filons-couches de gabbro sous-jacents du Groupe Exploits. Considérant la combinaison des données d’analyse publiées et des datations de ces roches, les roches volcaniques et les filons-couches sont indiscernables tant en composition qu’en âge, et les données sont compatibles avec l’hypothèse selon laquelle ils représentent le même événement magmatique (principalement E-MORB) du Darriwilien précoce à moyen (~465 ± 2 Ma). Les LHV ainsi que les strates de l’encaissant renferment des indices régionaux qui montrent : 1) que le volume et la granulométrie des matériaux volcanoclastiques d’arc diminuent vers le haut dans l’intervalle supérieur des strates de turbidites sédimentaires sous les LHV; 2) que le changement vers des milieux marins peu profonds localement vers la fin de l’événement des LHV a été suivi immédiatement par une subsidence importante, et 3) qu’il n’existe pas d’indices d’apports clastiques à gros grains, non plus que de formation de failles normales, durant ou immédiatement après le magmatisme des LHV. L’interaction crête-fosse (subduction de la crête) au lieu d’un système de subduction concorde avec toutes ces caractéristiques et la répartition spatiale des éléments reliés, alors qu’une origine de crête (arrière-arc) au-dessus d’une zone de subduction ne peut expliquer que les compositions et qu’elle est incompatible avec l’évidence géologique. Le Dunnage Mélange (DM) a été interprété soit comme un olistostome dans un bassin d’arrière-arc en développement, ou comme un prisme d’accrétion de subduction. Les intrusions hyperalumineuses dans le mélange (Porphyre Coaker — CP), s’explique plus facilement par une subduction de crête, et un âge de datation sur zircon de (469 ± 4 Ma) correspond à l’âge des LHV et des filons-couche de gabbro, aussi interprétés comme produits d’une subduction de crête. La localisation du CP dans la portion orientale du DM, et de la majeure partie des grands blocs volcaniques dérivés des LHV de la portion ouest du DM, suggère un âge légèrement plus jeune, et peut-être un mécanisme différent, pour l’origine de la portion ouest du DM.
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Victor, Jonathan D., Mary M. Conte, Leslie Burton, and Ruth D. Nass. "Visual evoked potentials in dyslexics and normals: Failure to find a difference in transient or steady-state responses." Visual Neuroscience 10, no. 5 (September 1993): 939–46. http://dx.doi.org/10.1017/s0952523800006155.
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AbstractWe measured transient and steady-state checkerboard contrast-reversal visual evoked potentials (VEPs) in ten dyslexics, five patient controls, and 11 normals over a range of contrasts and luminances. Latency, amplitude, and phase measurements failed to distinguish the responses of dyslexics from those of normals or patient controls. Decreases in luminance or contrast resulted in an increased latency of the transient VEP in all groups, but these changes also did not distinguish the responses of dyslexics from those of the controls. Response variability was similar in dyslexics and normals, but was increased in subjects with attention deficit-hyperactivity disorder (ADHD). Performance on standardized psychometric testing did differentiate the dyslexics from controls, but did not correlate with VEP responses.
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Fioretto, P., R. Trevisan, A. Valerio, A. Avogaro, M. Borsato, A. Doria, A. Semplicini, et al. "Impaired renal response to a meat meal in insulin-dependent diabetes: role of glucagon and prostaglandins." American Journal of Physiology-Renal Physiology 258, no. 3 (March 1, 1990): F675—F683. http://dx.doi.org/10.1152/ajprenal.1990.258.3.f675.
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The renal response to 100 g/1.73 m2 protein load in the form of a meat meal was studied in 19 normal subjects and 35 normoalbuminuric insulin-dependent diabetic patients (IDDs) under conditions of sustained euglycemia. The area under the glomerular filtration rate (GFR) curve rose above base line by 1,904 +/- 292 in normals and 502 +/- 237 ml/1.73 m2 in IDDs (P less than 0.01). The meat meal induced a greater increment in the area under the glucagon curve in normals (14,930 +/- 186 pg.ml-1.min-1) than in IDDs (7,227 +/- 67, P less than 0.01); similarly urinary excretion of prostaglandin E2 and 6-ketoprostaglandin F1 alpha rose by 119 and 98%, respectively, in normals but only by 2% (P less than 0.01 vs. normals) and 10% (P less than 0.01 vs. normals) in IDDs. The fractional albumin clearance rose by 102 and 251% in normals and IDDs, respectively. In five normal subjects indomethacin administration abolished the GFR, glucagon, prostaglandin, and albuminuric response to meat ingestion. Glucagon replacement under indomethacin treatment failed to restore these responses. In five diabetic patients, selected for having a flat glucagon and GFR response to a meat meal, replacement of glucagon to postprandial levels increased urinary vasodilatory prostaglandins and restored a normal GFR response. Thus in normal subjects renal vasodilatory prostaglandins appear to be the final effector of the renal hemodynamic and albuminuric response to a meat meal. The prostaglandin increase is likely to be mediated under physiological conditions by a glucagon rise, which, however, has no effect per se on renal hemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)
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Penney, David G., and Bernd G. Barthel. "Effects of thyroid and growth hormone deficiency, and food restriction on heart mass, with and without added stress (carboxyhemoglobinemia)." Canadian Journal of Physiology and Pharmacology 63, no. 6 (June 1, 1985): 642–48. http://dx.doi.org/10.1139/y85-107.
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The roles of thyroid and growth hormone, and food restriction in maintenance of heart mass and in carbon monoxide-stimulated cardiac growth were examined. First, thyroidectomized and normal adult male rats inhaled up to 500 ppm CO in air for 42 days. Combined ventricular weights of thyroidectomized rats inhaling CO and air were 12 and 23% smaller than predicted, respectively, while the combined ventricular weight of normal rats inhaling CO was 29% larger than predicted. Thyroidectomy increased the mass of the left ventricle relative to the right ventricle; this was reversed by CO treatment. While the hematocrit increased in thyroidectomized–CO rats, it was lower than in normal–CO rats: likewise the hematocrit of thyroidectomized–AIR rats was lower than that of normal rats in air. Body weights of the thyroidectomized rats were 57% that of normals. As additional controls, two groups of normal rats (one AIR, one CO) were maintained at the same body weight as the thyroidectomized rats, by adjusting food intake. Combined ventricular weight was less than predicted in AIR rats and failed to increase in CO animals, while hematocrits were the same as normals in air and in CO. Serum thyroxine (T4) and growth hormone levels assayed in thyroidectomized rats were less than 15 and 25% of normal rats, respectively. Growth hormone levels were not altered by CO inhalation in thyroidectomized and in normal rats. Levels of both hormones were normal in food-restricted rats. While thyroidectomy produced cardiac atrophy, cardiac growth was stimulated by CO inhalation, although heart mass then only approached that of normals in air. Food restriction also produced cardiac atrophy, but CO inhalation failed to stimulate heart growth.
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Frederick, Angela. "Risky Mothers and the Normalcy Project." Gender & Society 31, no. 1 (January 9, 2017): 74–95. http://dx.doi.org/10.1177/0891243216683914.
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Feminist scholars have been critical of the expectations placed upon mothers to accomplish a perfect version of motherhood, but have often failed to interrogate the values about normalcy and disability imbedded in modern mothering ideologies. Mothers with disabilities are well positioned to expose the underlying beliefs about normalcy with which all mothers must contend. Drawing from interviews and focus groups conducted with mothers who have physical and sensory disabilities, I explore Deaf/disabled women’s experiences negotiating the scientific motherhood regime. Illuminating a paradox, I argue these women are labeled “risky mothers” under scientific motherhood, which prizes the management of risk and the prevention of disability. Yet, these mothers are simultaneously rendered invisible by inaccessible and inflexible medical practices, and by a consumer market of expert advice which prescribes that mothers inhabit a typical body. These women’s experiences illuminate the normalcy project as a central tenet of scientific motherhood.
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Salgado Durán, Andrés. "Pórticos prefabricados: uniones de elementos que mejoran su reacción frente a cargas = Precast frame constructions: connections that improve reaction through loads." Anales de Edificación 3, no. 1 (April 30, 2017): 44. http://dx.doi.org/10.20868/ade.2017.3534.
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ResumenEl éxito del rendimiento de las estructuras prefabricadas se basa en la forma en que estos elementos aisladosconfiguran un edificio entero mediante sus conexiones. En la superposición de dos piezas, a veces es difícil hacer que aparezcanfallas comunes denominadas separación y extracción. Con el fin de mejorar la eficiencia de las articulaciones, esta investigaciónmuestra nuevas formas de construir uniones mejores y más desarrolladas, listas para sostener no sólo cargas normales sinotambién externas como fuerzas sísmicas.AbstractThe success of performance of prefabricate structures is based on the way these isolated elements configure an entirebuilding by its connections. Overlap two pieces sometimes is difficult making common failures appear called splitting and pullout.In order to improve a better efficiency of joints, this investigation shows new ways to build better and more developed unions,ready to hold not only normal charges but also external as seismic forces.
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Liu, Y. Y., J. B. Cao, H. S. Fu, Z. Wang, Z. Z. Guo, and R. J. He. "Failures of Minimum Variance Analysis in Diagnosing Planar Structures in Space." Astrophysical Journal Supplement Series 267, no. 1 (July 1, 2023): 13. http://dx.doi.org/10.3847/1538-4365/acdd58.
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Abstract Minimum variance analysis of the magnetic field (MVAB), among various techniques of planar structure analysis, is most widely used for its numerical simplicity and loose requirements for data. Through a large number of studies based on MVAB, a global picture of the solar wind intermittency has been established. However, the huge discrepancy between the results from MVAB and other techniques like timing/triangulation implies that the uncertainty of MVAB is a crucial issue that is not fully understood. Utilizing Cluster data, we establish a data set comprised of 6752 discontinuities, whose orientations are precisely determined by timing, as a benchmark for testing MVAB. We find that the scatter of the MVAB normals around the timing normal can be reduced by elevating the threshold for the eigenvalue ratio λ 2/λ 3 and narrowing the data window to which MVAB is applied. The misidentification of discontinuities with B N / ∣ B ∣ < 0.4, Δ∣ B ∣/∣ B ∣ < 0.2 as rotational discontinuities (RDs, identified by B N / ∣ B ∣ > 0.4, Δ∣ B ∣/∣ B ∣ < 0.2) is proved to be a major and inherent defect of MVAB, which can occur even when λ 2/λ 3 is large. Such a misidentification process is revealed to be related to a special discontinuity geometry. It also explains the false RD predominance reported by previous studies based on MVAB. Finally, we provide advice for the application of MVAB and discuss the possibility of obtaining the real statistical properties of interplanetary discontinuities by using MVAB.
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Aranguren, Aitor, Julia Cuevas, José María Tubía, Manuel Carracedo, and Francisco J. Larrea. "La faille de Conquista: Caractérisation structurale et cinématique d'un cisaillement ductile dextre à composante normale dans le domaine sud de l'Arc ibéro-armoricain." Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 325, no. 8 (October 1997): 601–6. http://dx.doi.org/10.1016/s1251-8050(97)89461-x.
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Theodore, J. G., P. Kaliraj, S. Jayachandran, and K. Jayaraman. "Cloning, over-expression and evaluation of a recombinant fusion protein of Wuchereria bancrofti towards its application as a diagnostic agent for bancroftian filariasis." Parasitology 106, no. 4 (May 1993): 413–20. http://dx.doi.org/10.1017/s0031182000067160.
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SUMMARYA low molecular weight (15 kDa) surface antigen of the cattle filarial nematode, Setaria digitata, was earlier shown to be specifically recognized by the antibodies from human bancroftian filarial (Mf positive) patients' sera (Theodore & Kaliraj, 1990). The filarial specific antibodies bound to a 15 kDa peptide in preparative Western blots were eluted and employed in screening of candidate antigens expressed in the genomic library of Wuchereria bancrofti at the IgG4 subclass antibody level. A recombinant clone (λ WbG7) reacting strongly with filarial sera but poorly with sera from patients infected with non-filarial helminths was selected for further studies. The 2 kb DNA insert of the clone λ WbG7 was recloned into a pMAL vector and the recombinant clone pGT7 thus obtained was over-expressed and affinity purified. The purified 105 kDa fusion protein of the clone pGT7 was specific and was not recognized by the non-filarial sera at the IgG4 level. All microfilaraemic individuals were positive by IgG4 assay. However, similar attempts to diagnose by filarial-specific IgE assays failed to recognize microfilaraemic individuals. Moreover, by filarial-specific IgG4 assays, the endemic normals were distinctly divided into two groups, showing higher and lower recognition for this antigen indicating current and past/no infection. Among the filarial-IgG4 (assay)-positive ‘endemic normals’, 14% showed ‘microfilariae’ during repeated peripheral night blood examination, confirming the validity of the recombinant antigen, pGT7 based assay.
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de Saint Blanquat, Michel. "La faille normale ductile du massif du Saint Barthélémy. Evolution hercynienne des massifs nord-pyrénéens catazonaux considérée du point de vue de leur histoire thermique." Geodinamica Acta 6, no. 1 (January 1993): 59–77. http://dx.doi.org/10.1080/09853111.1993.11105239.
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RAMASWAMY, SHANKARAN, and JEFFERY K. HOVIS. "Ability of the D-15 panel tests and HRR pseudoisochromatic plates to predict performance in naming VDT colors." Visual Neuroscience 21, no. 3 (May 2004): 455–60. http://dx.doi.org/10.1017/s095252380421313x.
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Color codes in VDT displays often contain sets of colors that are confusing to individuals with color-vision deficiencies. The purpose of this study is to determine whether individuals with color-vision deficiencies (color defectives) can perform as well as individuals without color-vision deficiencies (color normals) on a colored VDT display used in the railway industry and to determine whether clinical color-vision tests can predict their performance. Of the 52 color defectives, 58% failed the VDT test. The kappa coefficients of agreement for the Farnsworth D-15, Adams desaturated D-15, and Richmond 3rd Edition HRR PIC diagnostic plates were significantly greater than chance. In particular, the D-15 tests have a high probability of predicting who fails the practical test. However, all three tests had an unacceptably high false-negative rate (9.5–35%); so that a practical test is still needed.
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Penot-Lacassagne, Olivier. "Novölittérature… à la brisure des années 1970." Études françaises 54, no. 1 (January 16, 2018): 135–52. http://dx.doi.org/10.7202/1042870ar.
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Comment « l’aventure punk » française a-t-elle été écrite ? Quel en fut le récit « littéraire » ? Par quels mots s’est-elle dite ? Jean-François Bizot, Patrice Eudeline, Kriss Vilà et Yves Adrien ont relaté avec éclat les avatars de ces « années blanches », 1976-1980. Entre témoignage, manifeste, roman-photos et fiction fantastique, leurs récits rendent compte de la brisure punk : débâcle de l’utopisme des années 1960, présent effondré, horizon sans lendemain. Les protagonistes de leurs récits traversent le vaste champ des désillusions des années 1970 et 1980. Inaptes ou indifférents au recyclage néolibéral qui s’amorce, ils « survivent » comme ils peuvent, confrontés à deux écueils : leur marginalisation inutile, la récupération marchande du néant. Sursaut brutal, déchéance morbide. « Sur la route de la déperdition et de la rédemption » (Bizot), une écriture s’invente. Entre dérision et tragique, elle exhibe les impasses de ces années-là. Écriture d’une blank generation relatant les « ultimes convulsions » de révoltes moribondes ; écriture extrême butant sur les impasses du moment. Nous relirons ces récits qui se construisent sur les vides ou les failles de ce qu’on appelle la modernité libérale-libertaire. Récits certes isolés, mais qui, témoignant d’un impossible retour « à la normale », se tiennent de manière exemplaire sur la limite désolée de cette époque – le long après-68, époque qui ne cesse de hanter notre présent.
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Jacobson, Gary P., and Devin L. McCaslin. "A Reexamination of the Long Latency N1 Response in Patients with Tinnitus." Journal of the American Academy of Audiology 14, no. 07 (July 2003): 393–400. http://dx.doi.org/10.1055/s-0040-1715758.
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There have been disparate findings reported previously by investigators who have examined differences in the cortically generated N1 (i.e., N100) from control and tinnitus samples. Investigators have employed differing stimulation paradigms applied to relatively small subject samples. Accordingly, it is not surprising that there has been no unanimity in the reported findings. The present investigation was conducted to determine, once again, whether differences exist in the cortically generated N1 potential recorded from both normals and subjects with bothersome tinnitus. In this investigation both passive and selective auditory attention paradigms were employed. Subjects were a total of 63 adults (31 controls and 32 tinnitus patients). The mean score on the Tinnitus Handicap Inventory for the tinnitus group was 39 points. Results failed to reveal group differences in the latency of N1 across listening conditions. However, tinnitus patients demonstrated N1 potentials that were of significantly smaller amplitude than those obtained from normal subjects. These findings are consistent with those reported in previous investigations.
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Phillips, P. C. B. "Partially Identified Econometric Models." Econometric Theory 5, no. 2 (August 1989): 181–240. http://dx.doi.org/10.1017/s0266466600012408.
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This paper studies a class of models where full identification is not necessarily assumed. We term such models partially identified. It is argued that partially identified systems are of practical importance since empirical investigators frequently proceed under conditions that are best described as apparent identification. One objective of the paper is to explore the properties of conventional statistical procedures in the context of identification failure. Our analysis concentrates on two major types of partially identified model: the classic simultaneous equations model under rank condition failures; and time series spurious regressions. Both types serve to illustrate the extensions that are needed to conventional asymptotic theory if the theory is to accommodate partially identified systems. In many of the cases studied, the limit distributions fall within the class of compound normal distributions. They are simply represented as covariance matrix or scalar mixtures of normals. This includes time series spurious regressions, where representations in terms of functionals of vector Brownian motion are more conventional in recent research following earlier work by the author.
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Imamura, T., A. Yamadori, Y. Shiga, M. Sahara, and H. Abiko. "Is Disturbed Transfer of Learning in Callosal Agenesis due to a Disconnection Syndrome?" Behavioural Neurology 7, no. 2 (1994): 43–48. http://dx.doi.org/10.1155/1994/146072.
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Disturbed intermanual transfer of tactile learning in callosal agenesis has been interpreted as a sign of disconnection syndrome. We observed this sign in one of four acallosal patients with a conventional form-board task, and tried to elucidate the nature of the deficit. The form-board performance of the patient with disturbed transfer of learning totally depended on motor skill, while the other acallosals and normal controls executed the task based on spatial and somesthetic information. All acallosals and normals, however, failed to show transfer of learning with another tactile task which needed motor skill but not spatial-somesthetic information. These findings suggest that the task-performing strategies in form-board learning change the state of interhemispheric transfer. Unimanual learning effect is transferred if spatial-somesthetic information is acquired in the process of learning, but is not transferred if motor skill is the exclusive content of learning. We conclude that disturbed “transfer” of learning in some acallosals is not a true disconnection sign. It should be attributed to a lack of appropriate strategy, as a result of ineffective problem solving in tactile tasks.
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Gilbert, I. A., J. M. Fouke, and E. R. McFadden. "Heat and water flux in the intrathoracic airways and exercise-induced asthma." Journal of Applied Physiology 63, no. 4 (October 1, 1987): 1681–91. http://dx.doi.org/10.1152/jappl.1987.63.4.1681.
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To explore the relationship between the flux of heat and water within the respiratory tract during exercise and recovery to the development of exercise-induced asthma (EIA), we recorded airstream temperature at multiple points throughout the tracheobronchial tree in 10 normal and 10 asthmatic subjects before, during, and after cycle ergometry. In both groups, the intra-airway temperature fell progressively as ventilation increased, and there were no significant differences between the thermal profiles of the two populations at rest or during exercise. Calculation of water losses and the osmolality of the airway surface fluid failed to demonstrate significant airway drying in either group. With cessation of the work load, the airstream temperature increased abruptly, rising two times more rapidly in the asthmatics than the normals. Since the major source of heat in these experiments is the bronchial circulation, our findings suggest a reaction sequence consisting of vasoconstriction and airway cooling during exercise followed by a rapid resupply of heat when exercise ceases. The latter may cause the hyperplastic capillary bed in the airways of asthmatics to develop an exaggerated rebound hyperemia which may lead to airway edema and EIA.
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Fitzpatrick, E. A., J. S. Bryson, C. Rhoads, A. M. Kaplan, and D. A. Cohen. "T-deficient transmembrane signaling in CD4+ T cells of retroviral-induced immune-deficient mice." Journal of Immunology 148, no. 11 (June 1, 1992): 3377–84. http://dx.doi.org/10.4049/jimmunol.148.11.3377.
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Abstract The defective virus found in the LP-BM5 mixture of murine leukemia viruses induces a severe immune deficiency disease in C57BL/6 mice that is characterized by the activation and expansion of T and B cells that become unresponsive to normal immune stimuli. The nature of the biochemical lesion in these defective lymphocyte populations remains unknown. Flow cytometric analysis of the T cell population in infected animals has demonstrated expansion of both CD4+ and CD8+ subsets. Despite chronic expansion in vivo, CD4+ T cells by wk 4 postinfection failed to up-regulate cell surface IL-2R expression, produced IL-2, or proliferate in vitro in response to either Con A, Staphylococcal enterotoxin super-antigens, or anti-CD3 stimulation. Exogenous IL-2 did not restore the proliferative response and also failed to up-regulate IL-R expression on CD4+ T cells from infected mice, even though basal IL-2R expression was initially elevated compared to normals. In contrast, CD4+ T cells from infected mice could be induced to proliferate by stimulation with PMA and ionomycin resulting in IL-2R up-regulation, IL-2 production, and proliferation. Moreover, proliferation could also be induced by anti-CD3 plus PMA, although anti-CD3 plus ionomycin was without effect. These studies suggest that chronic expansion of CD4+ T cells in infected mice is probably not maintained by normal TCR signaling, which appears defective in these cells. In addition, the lesion in biochemical signaling appears to result in defective activation of protein kinase C, which can be overcome by direct activation with PMA.
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Ozcan, Muhit, Colleen Morton, Anna Solovey, Luke Dandelet, Ronald Bach, Robert Hebbel, Arne Slungaard, and Nigel Key. "Whole Blood Tissue Factor Procoagulant Activity Remains Detectable during Severe Aplasia following Bone Marrow and Peripheral Blood Stem Cell Transplantation." Thrombosis and Haemostasis 85, no. 02 (2001): 250–55. http://dx.doi.org/10.1055/s-0037-1615705.
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SummaryUsing a novel whole blood assay, we recently demonstrated that tissue factor procoagulant activity (TF PCA) is present in normal individuals. Preliminary experiments suggested that this activity is localized in the mononuclear cell fraction. Postulating that whole blood TF PCA would therefore be undetectable when monocytes and neutrophils are absent from peripheral blood, we assayed TF PCA during the peri-transplant period in 15 consecutive patients undergoing allogeneic (n = 12) or autologous (n = 3) bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT). Baseline (pre-transplant) mean TF PCA was higher in patients compared to normal controls (P <0.005). Unexpectedly, although TF PCA during the period of profound aplasia was significantly reduced compared to baseline (p <0.05), fully 55% of the initial activity remained detectable. During the engraftment phase, TF PCA returned to pre-transplant levels, with a linear correlation between monocyte counts and TF PCA (r = 0.63). In contrast to normal whole blood, incubation of aplastic samples with E. Coli lipopolysaccharide ex vivo failed to induce TF PCA. Throughout the period of study – but especially during the aplastic phase – the absolute number of circulating endothelial cells (CECs) that were TF antigen-positive was increased compared to normals (P <0.001). However, removal of these cells from whole blood samples failed to significantly diminish total TF PCA indicating that CECs alone could not account for the detectable TF PCA during aplasia. We conclude that neither circulating mature myelo-monocytic cells nor endothelial cells can account for all the functionally intact TF in peripheral blood. Further studies are needed to identify the other source(s) of TF PCA.
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ELLIOTT, R., B. J. SAHAKIAN, A. MICHAEL, E. S. PAYKEL, and R. J. DOLAN. "Abnormal neural response to feedback on planning and guessing tasks in patients with unipolar depression." Psychological Medicine 28, no. 3 (May 1998): 559–71. http://dx.doi.org/10.1017/s0033291798006709.
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Background. It has been suggested that patients with unipolar depression show abnormal responses to negative feedback in the performance of cognitive tasks. Positron emission tomography (PET) has previously identified blood flow abnormalities in depressed patients during cognitive performance. We have also used PET to identify regions where there is differential neural response to performance feedback in normal volunteers. In this study we aimed to test the hypothesis that blood flow in these regions, the medial caudate and ventromedial prefrontal cortex, would be abnormal in depressed patients.Methods. Six patients with unipolar depression and six matched controls were scanned using PET while performing cognitive tasks in the presence and absence of feedback.Results. Compared with controls, depressed patients failed to show significant activation in the medial caudate and ventromedial orbitofrontal cortex. Blood flow was lower and a differential response, observed in normals, under different task and feedback conditions was not seen in the patients.Discussion. The findings suggest that the behavioural response to feedback in depressed patients is associated with an abnormal neural response within the medial caudate and ventromedial orbitofrontal cortex, regions implicated in reward mechanisms. We argue that the observed abnormalities may depend on a combination of psychological factors, with both cognitive and emotive components.
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Alam, R., J. B. Welter, P. A. Forsythe, M. A. Lett-Brown, and J. A. Grant. "Comparative effect of recombinant IL-1, -2, -3, -4, and -6, IFN-gamma, granulocyte-macrophage-colony-stimulating factor, tumor necrosis factor-alpha, and histamine-releasing factors on the secretion of histamine from basophils." Journal of Immunology 142, no. 10 (May 15, 1989): 3431–35. http://dx.doi.org/10.4049/jimmunol.142.10.3431.
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Abstract Most cytokines possess multiple biologic activities. This study was undertaken to investigate the effect of rIL-1 beta, -2, -3, -4 and -6, IFN-gamma, TNF-alpha, and granulocyte-macrophage (GM)-CSF on basophils from 16 donors and the amount of histamine released was compared with that by partially purified mononuclear cell-derived histamine-releasing factor (HRF) and anti-IgE. We found that only IL-3 and GM-CSF at relatively high doses (50 to 500 ng/ml) released small amounts of histamine (3 to 14%) from two allergic donors. In contrast, both HRF and anti-IgE released significant amounts of histamine from all donors. Other cytokines did not release any measurable quantity of histamine. Simultaneous addition of several cytokines to the basophils also failed to release histamine. IL-3, GM-CSF, and IL-1 can also release histamine at lower concentrations (less than 5 ng/ml) when incubated with basophils in the presence of D2O. Basophils from 6 out of 13 allergic donors released histamine in response to IL-3, whereas three donors responded to IL-1 beta and two responded to GM-CSF. The results of this study demonstrated that although IL-3 and GM-CSF release small amounts of histamine only from a select group of allergic patients, mononuclear cell-derived HRF is more potent in their action and release histamine from normals as well as allergic patients.
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PATEL, Dilip D., Brian L. KNIGHT, Anne K. SOUTAR, Geoffrey F. GIBBONS, and David P. WADE. "The effect of peroxisome-proliferator-activated receptor-α on the activity of the cholesterol 7α-hydroxylase gene." Biochemical Journal 351, no. 3 (October 24, 2000): 747–53. http://dx.doi.org/10.1042/bj3510747.
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Cholesterol 7α-hydroxylase (Cyp7a1) plays a central role in the regulation of bile acid and cholesterol metabolism, and transcription of the gene is controlled by bile acids and hormones acting through a complex interaction with a number of potential steroid-hormone-binding sites. Transcriptional activity of the human CYP7A1 gene promoter transfected into HepG2 cells was decreased in a concentration-dependent manner by co-transfection with an expression vector for peroxisome-proliferator-activated receptor-α (PPARα). This effect was augmented by 9-cis-retinoic acid receptor-α (RXRα) and activators of PPARα to give a maximum inhibition of approx. 80%. The region responsible for this inhibition contained a site known to bind hepatocyte nuclear factor 4 (HNF4), and mutation of this site greatly decreased the effect. Co-expression of HNF4 increased promoter activity and decreased the effect of PPARα. Gel-mobility-shift assays failed to detect any binding of PPARα/RXRα dimers to any regions of the promoter containing potential binding sites. Also the hepatic abundance of Cyp7a1 mRNA in mice in which the PPARα gene was disrupted was the same as in normal mice, both during the dark phase, when the animals were feeding, and during the light phase, when mRNA abundance was greatly increased. Cholesterol feeding produced the same increase in hepatic Cyp7a1 mRNA abundance in PPARα-null animals as in normals. It is concluded that, whereas PPARα can affect CYP7A1 gene transcription in vitro through an indirect action, probably by competing for co-factors, this is unlikely to be a major influence on Cyp7a1 activity under normal physiological conditions.
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Van Rooyen, Deanne, and Sharon D. Carr. "Deconstructing the Infrastructure: A Complex History of Diachronous Metamorphism and Progressive Deformation during the Late Cretaceous to Eocene in the Thor-Odin–Pinnacles Area of Southeastern British Columbia." Geoscience Canada 43, no. 2 (May 18, 2016): 103. http://dx.doi.org/10.12789/geocanj.2016.43.097.
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The Thor-Odin dome is a basement-cored tectonothermal culmination in southern British Columbia containing high-grade metamorphic rocks that were polydeformed in the Late Cretaceous to Eocene. The rocks south of the Thor-Odin dome that extend ca. 20 km to the Pinnacles culmination and Whatshan batholith comprise a heterogeneous tract of polydeformed medium- to high-grade metamorphic rocks and host the South Fosthall pluton near the base of the structural section. They lie in the footwall of the Columbia River fault (CRF) zone, a moderately east-dipping, ductile-brittle, normal fault that was active after ca. 55 Ma and reactivated periodically up to 30 Ma. This tract of rocks has been interpreted as a mid-crustal zone that was exhumed and cooled during Eocene extension or, alternatively, a mid-crustal channel that was bounded at the top by the CRF and was active during the Late Cretaceous to Eocene. However, the timing of metamorphism, deformation, anatexis in basement rocks, and intrusion of leucogranite plutons reveals that there are four tectonothermal domains within the tract that each experienced metamorphism, deformation and cooling at different times. These rocks record Cretaceous metamorphism and cooling in the upper structural levels and three stages of progressive metamorphism and penetrative deformation that migrated into deeper crustal levels in the Paleocene and Eocene producing a complex structural section that was exhumed in part due to motion on the Columbia River fault zone, and in part due to NE-directed transport over a basement ramp.RÉSUMÉLe dôme de Thor-Odin correspond à une culmination tectonothermique d’un noyau de socle dans le sud de la Colombie-Britannique renfermant des roches métamorphiques de haute intensité polydéformées entre le Crétacé supérieur et l’Éocène. Les roches au sud du dôme de Thor-Odin qui s’étendent sur environ 20 km jusqu’à la culmination des Pinnacles et du batholite de Whatshan sont constituées d’une bande hétérogène de roches polydéformées à faciès métamorphique d’intensité moyenne à élevée qui constitue l’encaissant du pluton de South Fosthall près de la base de la colonne structurale. Elles se trouvent dans l'éponte inférieure de la zone de faille de la rivière Columbia (CRF), une faille normale à pendage modéré vers l’est, ductile-fragile, qui a été active après 55 Ma environ et a été réactivée périodiquement jusqu'à 30 Ma. Cette bande de roches a été interprétée comme une zone de mi-croûte qui a été exhumée et a refroidi durant l’extension éocène ou alors comme un canal mi-crustal qui a été limité au sommet par la CRF, et qui a été actif de la fin du Crétacé jusqu’à l’Éocène. Toutefois, la chronologie du métamorphisme, de la déformation, de l’anatexie dans les roches du socle, et de l'intrusion de plutons de leucogranite, montre qu'il existe quatre domaines tectonothermiques pour chaque bande qui ont subit du métamorphisme, de la déformation et du refroidissement à différents moments. Ces roches exhibent un métamorphisme et un refroidissement crétacé dans les niveaux structuraux supérieurs et trois stades de métamorphisme progressif et de déformation pénétrative qui ont migré dans les niveaux crustaux profonds au Paléocène et à l’Eocène constituant ainsi une colonne structurale complexe qui a été exhumée en partie en raison du mouvement de la zone de faille de Columbia River, et en partie en raison du transport vers le N.-E. sur une rampe de socle.
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Roza, Carolina, Jennifer M. A. Laird, and Fernando Cervero. "Spinal Mechanisms Underlying Persistent Pain and Referred Hyperalgesia in Rats With an Experimental Ureteric Stone." Journal of Neurophysiology 79, no. 4 (April 1, 1998): 1603–12. http://dx.doi.org/10.1152/jn.1998.79.4.1603.
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Roza, Carolina, Jennifer M. A. Laird, and Fernando Cervero. Spinal mechanisms underlying persistent pain and referred hyperalgesia in rats with an experimental ureteric stone. J. Neurophysiol. 79: 1603–1612, 1998. Spinal neurons processing information from the ureter have been characterized in rats 1–4 days after the implantation of an experimental ureteric stone and compared with those of normal rats. The effects of a conditioning noxious stimulation of the ureter in the presence of the hyperalgesia evoked by the calculosis also were examined. Extracellular recordings were performed at the T12–L1 segments of the spinal cord. In rats with calculosis, more neurons expressed a ureter input (53 vs. 42% in normal rats); such cells being more likely to show background activity, at a higher rate than normals (6.6 ± 1.2 vs. 3.2 ± 0.9 spikes/s; mean ± SE) and increasing with the continuing presence of the stone. The threshold pressure for a ureteric response was higher than in normal rats (79 ± 5 vs. 54 ± 4 mmHg) but the neurons failed to encode increasing intensities of stimulation. Thirty-five percent of the neurons with exclusively innocuous somatic receptive fields had a ureter input in rats with calculosis, whereas none were seen in normal rats. A noxious ureteric distention applied to neurons with ureter input evoked a complex mixture of increases and decreases in somatic receptive field size and/or somatic input properties markedly different from the generalized increases in excitability seen when such a stimulus was applied to normal animals. We conclude that the presence of a ureteric stone evokes excitability changes of spinal neurons (enhanced background activity, greater number of ureter-driven cells, decreased threshold of convergent somatic receptive fields), which likely account for the referred hyperalgesia seen in rats with calculosis. However, further noxious visceral input occurring in the presence of persistent hyperalgesia produces selective changes that cannot be explained by a generalized excitability increase and suggest that the mechanisms underlying maintenance of hyperalgesia include alteration of both central inhibitory and excitatory systems.
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MONCALEANO, J. S., L. M. JIMÉNEZ, and C. A. SÁNCHEZ. "Mosaicismo leucocitario asociado a infertilidad en cuatro yeguas." Orinoquia 11, no. 1 (January 1, 2007): 87–91. http://dx.doi.org/10.22579/20112629.173.
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Titulo en ingles: Mosaicism leucocitary associated to infertility in four mares.RESUMEN: Se tomaron muestras de sangre periférica a cuatro yeguas de 19, 13, 10 y 4 años de edad, de raza Silla francesa, dos Criollas Colombianas y una Paso Fino Colombiano respectivamente, para realizar cultivo de linfocitos. Los animales fueron remitidos por la Clínica de Reproducción al Laboratorio de Citogenética Animal de la Facultad de Medicina Veterinaria y de Zootecnia de la Universidad Nacional de Colombia por antecedentes de problemas reproductivos. A la palpación se detectaron órganos reproductivos subdesarrollados; ausencia de preñez, además abortos frecuentes y en algunos casos nacimiento de potros inmaduros o con defectos fenotípicos. La evaluación citogenética se realizó mediante análisis de cromosomas obtenidos a partir de cultivo de linfocitos, y teñidos con Giemsa. El complemento cromosómico en todos los animales estudiados fue 63, XO/64,XX; las células con monosomía del X, (63,XO) oscilaron entre el 25% y 63% de las células analizadas y las células normales (64,XX) entre el 37% y el 75% . Los resultados de estos análisis demostraron los beneficios de este tipo de diagnostico para determinar fallas reproductivas que involucran anormalidades cromosómicas en yeguas que fenotipicamen no presentaban alteraciones evidentes.Palabras clave: monosomía, cromosomas sexuales, mosaicismo en yeguas.ABSTRACT: Heparinized blood samples for culturing leucocytes were taken from four mares that were 4, 10, 13, and 19 years old. They were of three different breeds. One was a French saddle horse, two were Colombian creoles, and the fourth was a fine stepping Colombian riding horse. The mares were remitted by the Clinic of Reproduction to the Animal Cytogenetic Laboratory of the School of Veterinary Medicine and Zootechnics of the National University of Colombia due to their history of reproductive failure. Rectal palpation revealed atrophic reproductive organs. Failure to conceive, frequent abortions, and birth of inmature foals, or those born with phenotypic defects, were noted in the mares’ histories. A cytogenetic evaluation was done by an analysis of the mares’ chromosomes that were obtained by culturing the leucocytes and staining them with Giemsa. The chromosome complement was 63,XO/64,XX for all samples. The cells analyzed with X monosomy (63,XO) varied from 25% to 63%, and the normal cells (64,XX) varied from 37% to 75%. The results of this analysis demonstrated that this diagnostic tool is beneficial to determine reproductive failures due to chromosomal abnormalities in mares that didn’t show any evident phenotypic abnormalities.Key work: monosomy, sexual chromosome, mare mosaicism.
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Greipp, Patricia, Greg Cascino, Teresa Kimlinger, Vincent Rajkumar, Franklyn G. Prendergast, Rafael Fonseca, P. Leif Bergsagel, Philip S. Low, and Philip R. Greipp. "Plasma Cell Folate Receptor Overexpression Differentiates Multiple Myeloma from Monoclonal Gammopathy of Undetermined Significance and Smoldering Myeloma." Blood 104, no. 11 (November 16, 2004): 3649. http://dx.doi.org/10.1182/blood.v104.11.3649.3649.
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Abstract Background: Folate receptor (FR) is a recently recognized tumor marker that is being investigated for targeted delivery of drugs, imaging of cancer cells, and tumor immunotherapy. The small size of the molecule, simple conjugation chemistry and lack of immunogenicity make folate an ideal candidate for targeted delivery to tumors bearing the FR (Lu Y, Low PS. Folate-mediated delivery of macromolecular anticancer therapeutic agents. Adv Drug Deliv Rev. 2002 Sep 13;54(5):675–93). FR is overexpressed in 90% of ovarian cancers and in other human tumors including endometrial, colorectal, breast, and neuroendocrine carcinomas, it is negatively or only weakly expressed in most normal tissues including some myeloid cells. In view of the above we wished to learn if overexpression of FR by marrow plasma cells (PC) might differentiate MM from MGUS and SMM. Methods: We obtained marrow biopsy sections from 20 patients each with MM, MGUS, or SMM, and 11 normals and stained them by immunohistochemistry using a FR-beta antibody. Expression was graded 0 (negative), 1 (equivocal), 2 (positive) or 3 (strong positive) based on immunohistochemical staining of marrow PC. We recorded the percent PC, percent positive PC, and the staining of other cell types including myeloid, erythroid, lymphocytes, macrophages, megakaryocytes and control tissues. Results: PC of patients with MM positively expressed FR compared to MGUS, SMM and normal PC (p<0.0001) (Figure 1 and 2). Of interest, 6 of 20 SMM patients showed positive expression. Maturing myeloid cells were also positive, acting as internal positive controls. Macrophages were often positive; some endothelial cells were positive; early erythroid precursors were rarely positive; megakaryocytes, maturing erythroid precursors and lymphocytes did not express FR. The chromosomal location of the FOLR gene cluster is 11q13. Gene expression arrays of purified PC failed to show evidence of overexpression of FOLR1, FOLR2, or FOLR3. We are currently performing Western blots to examine levels of protein product of purified PC. Conclusion: Immunohistochemistal studies show differential expression of FR in MM PC compared to absent or equivocal expression in MGUS and normal PC and variable expression in SMM. The data suggest that FR may be used as a diagnostic tumor marker and has implications for development of folate-based tumor imaging, drug delivery, and immunotherapy. Figure Figure Figure Figure
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Verfaillie, C., W. Miller, N. Kay, and P. McGlave. "Adherent lymphokine-activated killer cells in chronic myelogenous leukemia: a benign cell population with potent cytotoxic activity." Blood 74, no. 2 (August 1, 1989): 793–97. http://dx.doi.org/10.1182/blood.v74.2.793.793.
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Abstract We generated a homogeneous population of cells with cytotoxic activity termed “adherent lymphokine-activated killer” (ALAK) cells from the peripheral blood of nine patients in the chronic phase of Ph1 positive chronic myelogenous leukemia (CML). The selective enrichment of CML ALAK cells depended on their propensity to adhere to plastic and proliferate when cultured in the presence of recombinant interleukin-2 (rIL-2) for 14 days. Culture of peripheral blood mononuclear cells under these conditions resulted in growth of a uniform population of cells with morphologic characteristics of large granular lymphocytes. The NKH1+/CD3- phenotype associated with IL-2-stimulated natural killer (NK) cells was present on 79% +/- 9% of cells. Absence of colony formation in conditions promoting the growth of CFU-GEMM indicated that the CML ALAK population was not contaminated with viable hematopoietic progenitors. Cytogenetic analysis of the CML ALAK population revealed 119/120 Ph1 negative metaphases and l/120 Ph1 positive metaphase in six patients. Southern blot analysis of CML ALAK failed to demonstrate a bcr gene rearrangement in seven patients known to have a bcr gene rearrangement in myeloid cells. Comparison of ALAK populations derived from peripheral blood of CML patients and normals revealed similar cytotoxicity against the NK-sensitive K562 cell line (104 +/- 36 LU v 88 +/- 19 LU; P = NS) and the NK-resistant Raji cell line (93 +/- 26 LU v 98 +/- 28 LU; P = NS). The proliferative capacity of CML ALAK cells (101 +/- 33 fold expansion) exceeds the growth potential of the normal ALAK cells (22.3 +/- 3 fold expansion; P = .02). Direct comparison of equal numbers of CML ALAK cells and a CML LAK cell population produced by incubation of peripheral blood mononuclear cells in rIL-2 for 14 days without adherence revealed that the CML LAK population had significantly lower lytic activity against K562 and Raji cell lines. We are able to expand CML peripheral blood mononuclear cells to provide a population of ALAK cells with potent cytotoxic activity. The CML ALAK population is relatively homogeneous, not contaminated with viable stem cells, not derived from a malignant lineage, and more cytotoxic than equal numbers of CML LAK cells. Further studies are underway to determine if this ALAK population may be effective in autologous killing of chronic myelogenous leukemia stem cells.
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Verfaillie, C., W. Miller, N. Kay, and P. McGlave. "Adherent lymphokine-activated killer cells in chronic myelogenous leukemia: a benign cell population with potent cytotoxic activity." Blood 74, no. 2 (August 1, 1989): 793–97. http://dx.doi.org/10.1182/blood.v74.2.793.bloodjournal742793.
Full textAbstract:
We generated a homogeneous population of cells with cytotoxic activity termed “adherent lymphokine-activated killer” (ALAK) cells from the peripheral blood of nine patients in the chronic phase of Ph1 positive chronic myelogenous leukemia (CML). The selective enrichment of CML ALAK cells depended on their propensity to adhere to plastic and proliferate when cultured in the presence of recombinant interleukin-2 (rIL-2) for 14 days. Culture of peripheral blood mononuclear cells under these conditions resulted in growth of a uniform population of cells with morphologic characteristics of large granular lymphocytes. The NKH1+/CD3- phenotype associated with IL-2-stimulated natural killer (NK) cells was present on 79% +/- 9% of cells. Absence of colony formation in conditions promoting the growth of CFU-GEMM indicated that the CML ALAK population was not contaminated with viable hematopoietic progenitors. Cytogenetic analysis of the CML ALAK population revealed 119/120 Ph1 negative metaphases and l/120 Ph1 positive metaphase in six patients. Southern blot analysis of CML ALAK failed to demonstrate a bcr gene rearrangement in seven patients known to have a bcr gene rearrangement in myeloid cells. Comparison of ALAK populations derived from peripheral blood of CML patients and normals revealed similar cytotoxicity against the NK-sensitive K562 cell line (104 +/- 36 LU v 88 +/- 19 LU; P = NS) and the NK-resistant Raji cell line (93 +/- 26 LU v 98 +/- 28 LU; P = NS). The proliferative capacity of CML ALAK cells (101 +/- 33 fold expansion) exceeds the growth potential of the normal ALAK cells (22.3 +/- 3 fold expansion; P = .02). Direct comparison of equal numbers of CML ALAK cells and a CML LAK cell population produced by incubation of peripheral blood mononuclear cells in rIL-2 for 14 days without adherence revealed that the CML LAK population had significantly lower lytic activity against K562 and Raji cell lines. We are able to expand CML peripheral blood mononuclear cells to provide a population of ALAK cells with potent cytotoxic activity. The CML ALAK population is relatively homogeneous, not contaminated with viable stem cells, not derived from a malignant lineage, and more cytotoxic than equal numbers of CML LAK cells. Further studies are underway to determine if this ALAK population may be effective in autologous killing of chronic myelogenous leukemia stem cells.
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Cutler, Jacky A., Mike J. Mitchell, and Geoffrey F. Savidge. "A Novel Frameshift Mutation in a Case of Familial May-Hegglin Anomaly." Blood 104, no. 11 (November 16, 2004): 3033. http://dx.doi.org/10.1182/blood.v104.11.3033.3033.
Full textAbstract:
Abstract The May-Hegglin anomaly is a rare, autosomal dominant condition that is characterised by thrombocytopaenia, anisocytosis, and Dohlë-like inclusion bodies in leukocytes. The disorder generally results in a mild bleeding tendency. May-Hegglin anomaly results from defects in the MYH9 gene, which encodes the heavy chain of nonmuscle myosin IIA. The gene maps to chromosome 22q12.3-q13.2, comprises 40 exons, and produces a 5.8kb mRNA transcript. We present a case of familial May-Hegglin anomaly. This kindred was first identified, and published, in 1964; but no further analyses were carried out until recently. The proband, now aged 80 years, has a life long history of easy bruising and epistaxis, although the symptoms have improved with increasing age. Her sister (deceased) and daughter reported similar symptoms: the daughter requiring splenectomy for thrombocytopaenia at age 9 years. The proband has also suffered from deafness for in excess of 60 years. Recent investigations of the proband revealed a mild thrombocytopaenia, and the characteristic blood film of May -Hegglin anomaly. Platelet and neutrophil morphology were also consistent with the disorder. Karyotype analysis revealed good quality G banding throughout chromosome 22, and no gross alteration in the region 22q11.2., 22q13. Direct sequencing of the MYH9 gene identified a heterozygous deletion of a single base in a run of Gs at nucleotide positions 5818–5821 (codons 1940–1941). This frame shift mutation leads to the creation of a premature termination sequence at codon 1947, and the loss of the last fourteen amino acids. The deletion introduces a restriction site, and endonuclease digestion of a panel of normals failed to detect this change. Together with the fact that this is a conserved region across species (human, rat, rabbit, chicken), it is probable that this deletion is the causative mutation in this kindred. This novel mutation represents the second reported defect affecting the tail-piece domain in May-Hegglin anomaly. The protein’s two heavy chains homodimerise in this region to form a tail, and multiple polypeptides associate through this tail domain to form bipolar filaments. Therefore, a mutation in this domain may exert its effect by the inhibition of myosin filament assembly. To date, approximately 20 different mutations have been described in the MYH9 gene giving rise to not only May-Hegglin anomaly, but also the similar disorders of Fechtner syndrome, Sebastian syndrome and Epstein syndrome. In fact some mutations have been identified in patients with different diagnoses. The proband presented here has a long standing diagnosis of May-Hegglin anomaly, but does exhibit one symptom (deafness) more usually associated with Fechtner syndrome. The genetic, phenotypic and clinical overlap in these disorders suggest that these actually represent allelic variations of a single genetic disorder, which should more correctly be termed ‘MYHIIA syndrome’.
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Pai, Howard Huaihan, Tom Pickles, Mira Keyes, Stuart Jones, Rachel E. McDonald, Mary Lesperance, and Eric Berthelet. "Randomized study evaluating testosterone recovery using short-versus long-acting luteinizing hormone releasing hormone agonists." Canadian Urological Association Journal 5, no. 3 (April 4, 2013): 173. http://dx.doi.org/10.5489/cuaj.639.
Full textAbstract:
Introduction: We sought to compare the rate of return of testosteronelevels and sexual function in men with prostate cancerreceiving longer acting, 3-month preparation of luteinizing hormone-releasing hormone agonist (L-LHRH-A) versus shorter acting,1-month preparation of luteinizing hormone-releasing hormoneagonist (S-LHRH-A).Methods and Materials: Men with low to intermediate risk localizedprostate cancer were randomized to either L-LHRH-A (2-3 monthduration LHRH-A) or S-LHRH-A (6-1 month duration LHRH-A) ofandrogen suppression therapy (AST) and prostate brachytherapyusing iodine-125 radioisotopes. Serum total testosterone levels andPSA were recorded every 2 months for 2 years.Results: A planned target sample size of 100 was not achieveddue to insufficient accrual. A total of 55 patients were randomizedand 46 were used for analysis. The median time to recovery oftestosterone to baseline levels (calculated from end of AST) was 8and 4 months in the L-LHRH-A and S-LHRH-A arms, respectively(p = 0.268). The median time to testosterone recovery to lower limitof reference range was 4 and 2 months respectively (p = 0.087).Interpretation: This randomized study, which failed to reachaccrual target, showed a trend towards more rapid recovery oftestosterone levels using shorter acting LHRH-A. Another randomizedstudy would be required to validate these findings. Currently,there is insufficient evidence to recommend the use of shorteracting LHRH-A as a means of providing more rapid recovery oftestosterone levels.Introduction : Nous avons voulu comparer la vitesse de retourdes taux de testostérone et de la fonction sexuelle chez des hommesatteints d’un cancer de la prostate recevant un agoniste de laLHRH à longue durée d’action pendant 3 mois ou un agoniste dela LHRH à courte durée d’action pendant 1 mois.Matériel et méthodologie : Des hommes atteints d’un cancer dela prostate localisé avec risque faible à intermédiaire ont été randomiséspour recevoir soit un agoniste de la LHRH à longue duréed’action (2 doses trimestrielles) soit un antagoniste de la LHRHà courte durée d’action (6 doses mensuelles) comme traitementantiandrogène et une brachythérapie prostatique avec des radioisotopesde l’iode 125. Les taux sériques de testostérone totale etd’APS ont été notés tous les 2 mois pendant 2 ans.Résultats : L’échantillon prévu au départ de 100 patients n’apu être obtenu en raison d’un recrutement insuffisant. Au total,55 patients ont été randomisés et 46 ont été inclus dans les analyses.L’intervalle médian de retour à des taux normaux de testostérone(calculés à partir de la fin du traitement antiandrogène) étaitde 8 et 4 mois dans les groupes sous agoniste de la LHRH à longueet à courte durée d’action, respectivement (p = 0,268). L’intervallemédian requis pour que les taux de testostérone atteignent la limiteinférieure des valeurs de référence était de 4 et 2 mois, respectivement(p = 0,087).Interprétation : Cette étude randomisée, où on n’a pas réussi àobtenir le nombre de patients voulu, a montré une tendance vers unretour plus rapide des taux de testostérone avec un traitement paragoniste de la LHRH à courte durée d’action. Une autre étude randomiséeserait nécessaire pour valider ces résultats. Actuellement,on ne dispose pas de suffisamment de données pour recommanderun agoniste de la LHRH à courte durée d’action comme moyenpour ramener les taux de testostérone plus rapidement à la normale.
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Silbermann, Rebecca, Marina Bolzoni, Paola Storti, Benedetta Dalla Palma, Sabrina Bonomini, Judy Anderson, G. David Roodman, and Nicola Giuliani. "Bone Marrow Monocyte / Macrophage Derived Activin A Mediates the Osteoclastogenic Effects of IL-3 in Myeloma,." Blood 118, no. 21 (November 18, 2011): 3933. http://dx.doi.org/10.1182/blood.v118.21.3933.3933.
Full textAbstract:
Abstract Abstract 3933 Multiple myeloma (MM) is characterized by bone destruction with suppressed new bone formation that is mediated by multiple factors including MIP-1α (CCL3), RANKL, IL-3, DKK1 and recently, Activin A (ActA). IL-3 is a bifunctional cytokine that indirectly increases osteoclastogenesis and suppresses osteoblastogenesis via CD14+ bone marrow monocytes (BMM). Additionally, IL-3 levels are elevated in the BM plasma of MM patients compared with normals, however the mediators of IL-3's effects on myeloma bone disease are unknown. To investigate this we performed gene expression profiling using Affymetrix GeneChip® analysis of IL-3 treated BMM from MM patients and found ActA gene expression was increased 180-fold and confirmed this finding at the protein level by ELISA. ActA is a negative regulator of bone mass that promotes osteoclastogenesis and is overproduced in MM patients. Interestingly, treatment of MM cells or bone marrow stromal cells (BMSC) with IL-3 did not induce secretion of ActA. We found that ActA was produced by MM and MGUS patient CD14+ cells treated with IL-3 to a significantly higher degree compared to healthy subjects. (Median ActA levels for MM and MGUS ActA levels were increased 66.57 and 51.6 fold respectively over untreated cells, while IL-3 treatment of normal cells increased ActA 8.5 fold.) ActA levels were also increased in freshly isolated marrow plasma of a cohort of patients with active MM as compared to patients with smoldering MM (SMM), MGUS, or healthy subjects (median ActA levels: active MM 453 pg/ml, SMM 328 pg/ml, MGUS 332 pg/ml, normal 286 pg/ml). ActA levels in MM patients with and without bone disease were not significantly different. (Median value with bone disease 463pg/ml vs. 407 pg/ml without bone disease.) ActA has also been reported to have a role in the differentiation and polarization of CD14+ tumor associated macrophages (TAMs), which are osteoclast precursors and can block MM cell apoptosis. Therefore, we examined the potential role of ActA in IL-3 mediated osteoclast (OCL) formation. Culture of normal BMM with ActA or IL-3 significantly enhanced osteoclastogenesis compared with control (mean number of OCL / 1×105 normal marrow non-adherent cells plated in IL-3 (100pg/ml) treated cultures 73; ActA (1ng/ml) treated cultures 123; cultures with vehicle alone, 8), and ActA enhanced RANKL-induced osteoclastogenesis. Osteoprotegerin treatment of normal donor BMM stimulated with ActA failed to block the osteoclastogenic effects of ActA, demonstrating that ActA's osteoclastogenic effects were RANKL independent. Importantly, the osteoclastogenic effect of IL-3 was dose-dependently inhibited by anti-ActA, and IL-3 induced ActA expression by BMM decreased during OCL differentiation. In support of early OCL precursors as the source of IL-3 induced ActA, we did not identify IL-3 receptors on mature OCL by flow cytometry. These results demonstrate that IL-3 induction of osteoclastogenesis is mediated by ActA produced by CD14+ BMM and is RANKL independent. Thus, we hypothesize that therapies targeting the ActA receptor, such as the recently developed ActA receptor antagonist, should block both IL-3 and ActA, and thereby significantly impact MM bone disease via their effects on TAMs. Disclosures: Bolzoni: Celgene Italy: Research Funding. Roodman:Millennium: Consultancy; Amgen: Consultancy. Giuliani:Celgene: Research Funding; Novartis: Research Funding.
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Gutiérrez-Abril, Jesús, Gunes Gundem, Elise Fiala, Konstantinos Liosis, Noushin Farnoud, Daniel Leongamornlert, Anu Amallraja, et al. "A D e Novo Supernumerary Ring Chromosome 1 Causes B-Cell Acute Lymphoblastic Leukemia in Monozygotic Twins Due to Independent and Partially Convergent Evolutionary Trajectories." Blood 142, Supplement 1 (November 28, 2023): 4352. http://dx.doi.org/10.1182/blood-2023-181194.
Full textAbstract:
Introduction B-cell acute lymphoblastic leukemia (B-ALL) is the most common pediatric cancer. In recent years, our understanding of B-ALL biology has benefited from genomic and transcriptomic analyses that identify driver alterations in 98% of patients. In addition, prior studies of monozygotic twins, who both developed B-ALL, have provided insight into the developmental timing and natural history of the disease, as well as the identification of novel mechanisms of leukemogenesis. Herein we study a case of monozygotic twins, who developed B-ALL (Table 1). We report the characterization of a de novo supernumerary ring chromosome 1 (SRC1) as an initiator event that followed independent but partially convergent clonal trajectories in each twin. Thus, SRC1 resulted in genomic rearrangements of MEF2D in both twins but targeted distinct fusion gene partners ( BCL9 versus ARNT). To our knowledge, this study represents the first description of MEF2D-ARNT as an event involved in B-ALL, and the association of SRC1 Syndrome with leukemia. Methods We performed integrative whole genome sequencing (WGS) and RNAseq analysis on B-ALL samples at diagnosis and compared this to WGS data from minimal residual disease negative bone marrow aspirates. Coverage levels for tumors and matched normals were: Twin A=104 & 59; Twin B=81 & 53. Tumor purity estimations were 0.80 in Twin A and 0.31 in Twin B. For RNAseq, expression profile efficiencies were 61% and 36% respectively. Comprehensive variant calling was performed using the Isabl platform (Medina et al, 2020) to map all putative somatic and germline events. ALLCatchR (Beder et. al, 2022) was used for molecular B-ALL subtype allocation in 26 samples from our pediatric cohort of patients including the twins (age range 1-23), and MutationTimeR (Gerstung et al, 2020) to calculate the relative timing of copy number gains. All research studies were approved by NYU and MSKCC Institutional Review Boards. Results The tumor mutational burdens for each leukemia sample were 0.86 for Twin A and 0.47 mutations/Mb for Twin B, and they showed independent alterations in oncogenic genes (Table 1). The only B-ALL driver that both twins had partially in common was an intrachromosomal translocation resulting in MEF2D fusions, but each with a distinct partner gene ( BCL9 versus ARNT) which was confirmed by RNAseq (supporting reads: Twin A=48, Twin B=107) and PCR assays (Fig. 1). Each sample demonstrated enhanced transcription levels of MEF2D compared to our reference B-ALL cohort (transcripts per million: Twin A=48.0, Twin B=77.4, median=27.7, sd=19.9), and were transcriptionally classified as MEF2D-subtype by the ALLCatchR classifier. These results functionally supported the role of MEF2D-ARNT as a new oncogenic event. Analysis of germline variants showed a tandem duplication flanking the pericentromeric region of chromosome 1 in both twins (1:120,163,074-157,714,717) where MEF2DBCL9and ARNT are localized, that had been previously identified as SRC1 in only one of them by constitutional genotyping (Table 1). Cell fractions in normal and tumor tissues were: Twin A=14.8% & 50%, Twin B=8.6% & 26.5%. PCR interrogation of parental germline DNA failed to identify SRC1, suggesting this to be a de novo event in the affected twins (Fig. 1). We compared the relative timepoint in which the SRC1 took place in each sample using MutationalTimeR, but we were only able to obtain results in Twin A due to a higher mutational burden (number of variants in SRC1: Twin A=44, Twin B=13). As expected, the tandem duplication that formed the SRC1 was identified as an early mutational event (confidence interval of relative time of appearance: 0-0.4). Conclusions Our results identify SRC1 as the common initiating genomic event leading to MEF2D fusion driven B-ALL in both twins. These findings support a model in which a tandem duplication around a pericentromeric area was an initiating event which caused the scission and circularization of DNA without the loss of genetic material. This led to a de novo acquisition of a SRC1, that after independent but partially convergent clonal trajectories gave rise to 2 distinct oncogenic MEF2D fusion driven leukemias in each twin . Moreover, ARNT is a novel partner gene to MEF2D which has not been previously described. This is the first report of B-ALL association with SRC1 Syndrome, which emphasises the utility of the study of monozygotic twins to identify novel alterations underlying B-ALL.
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Konstantinovskaya, Elena, Gennady Ivanov, Jean-Louis Feybesse, and Jean-Luc Lescuyer. "Structural Features of the Central Labrador Trough: A Model for Strain Partitioning, Differential Exhumation and Late Normal Faulting in a Thrust Wedge under Oblique Shortening." Geoscience Canada, March 29, 2019, 5–30. http://dx.doi.org/10.12789/geocanj.2019.46.143.
Full textAbstract:
The west-verging fold and thrust belt of the Central Labrador Trough originated as a part of the New Quebec Orogen from rift inversion as a result of oblique collision and dextral transpression between the Archean Superior craton and the Archean block of the Core Zone during the Trans-Hudson orogeny (1.82−1.77 Ga). The structures associated with dextral transpression are well established in the northern segment of the orogen but not in the central part. We present new field structural observations along the ca. 70 km long W−E Minowean-Romanet transect that include not only elements of thrust tectonics but also previously undocumented examples of strike-slip shear zones and late brittle, semi-brittle and ductile extensional structures which occurred both in the frontal and rear parts of the thrust wedge. The newly described low-angle mineral lineation, axes of cylindrical folds and dextral mylonitic shear zones in the footwall of the Romanet Fault are oriented subparallel to the orogen and reflect the early phase of oblique convergence. Mineral lineations and striations on planes of normal faults in the hanging wall of the Romanet Fault are oriented orthogonal to the orogen and correspond to a later phase of exhumation driven by the combined effects of erosion and underplating. To explain the increase in the degree of exhumation along the orogen in the study area from NW to SE, we propose a model of strain partitioning and differential exhumation that resulted from longitudinal variations of shortening and erosion under an oblique convergence setting.RÉSUMÉLa partie centrale de la ceinture de plissement et de chevauchement de la Fosse du Labrador de vergence vers l’ouest fait partie intégrante de l’Orogène du Nouveau-Québec, et résulte de la collision oblique avec transpression dextre entre le craton Supérieur archéen et le bloc archéen de la Zone noyau pendant l’Orogenèse trans-hudsonienne (1.82−1.77 Ga). Les structures associées à la transpression dextre sont bien établies dans la partie nord de l’orogène mais pas dans la partie centrale. Nous présentons de nouvelles observations structurales de terrain le long de la traverse ouest−est Minowean-Romanet d’environ 70 km de long, qui comprennent non seulement des évidences de tectonique de chevauchement, mais également des exemples encore non documentés de zones de cisaillement ductile et de structures d’extension fragiles, demi-fragiles et ductiles à la fois dans les parties frontales et arrière du prisme d’accrétion tectonique. La linéation minérale à faible plongement récemment décrite, les axes de plis cylindriques et les zones de cisaillement mylonitique dextre dans le compartiment inférieur de la faille de Romanet sont subparallèles à l’orogène et reflètent une phase précoce de la convergence oblique. La linéation et les stries minérales sur les plans des failles normales dans le compartiment supérieur de la faille de Romanet sont orientées orthogonalement à l’orogène et correspondent à la phase ultérieure d’exhumation induite par les effets combinés de l’érosion et de l’accrétion basale. Pour expliquer l’augmentation du degré d’exhumation le long de l’orogène du nord-ouest au sud-est dans la zone d’étude, nous proposons un modèle de partitionnement de la déformation et de l’exhumation différentielle résultant des variations longitudinales du raccourcissement et de l’érosion dans un contexte de convergence oblique.
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"Homeostasis and Homeorhesis: Sustaining Order and Normalcy in Human-Engineered Complex Systems." International Journal on Engineering Technologies and Informatics 2, no. 3 (June 18, 2021). http://dx.doi.org/10.51626/ijeti.2021.02.00014.
Full textAbstract:
This letter explores the notions of biological homeostasis and homeorhesis for construction of hybrid decision & control laws for human-engineered complex systems. The complexity may remain dormant during normal operations, but it becomes acutely conspicuous when contributing to unanticipated cascading and pervasive failures. The objective here is to sustain order and normalcy under both anticipated and unanticipated anomalies, faults, and disturbances. As an example, macroscopic decision & control of material microstructures is presented.
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Anderson, Ronald. "Numéro 96 - juin 2012." Regards économiques, October 12, 2018. http://dx.doi.org/10.14428/regardseco.v1i0.14873.
Full textAbstract:
Partant du constat que toutes les crises financières se ressemblent (endettement excessif, vente panique d’actifs, etc.), je cherche à déterminer ce qui caractérise la crise financière de 2007. Je passe en revue les étapes du développement de la crise, depuis les premiers signaux d’alerte sur le marché du crédit hypothécaire nord-américain jusqu’à la crise des dettes souveraines de l’Eurozone. Je relève quatre leçons majeures qui, selon moi, devraient être attentivement étudiées par tous ceux qui s’intéressent à la gestion des institutions financières majeures, à la définition de nouvelles règles prudentielles pour les banques et à la conception des politiques budgétaires et monétaires.
Leçon 1. L’économie globalisée s’appuie sur un secteur financier qui est lui-même globalisé. La santé de l’ensemble des banques au niveau mondial est profondément liée à l’ensemble du système financier. En particulier, les liens entre les banques et ce que l’on peut appeler le système bancaire parallèle (shadow banking sector) sont très nombreux. Par système bancaire parallèle, on entend notamment les compagnies d’assurances, les fonds de pension, les fonds d’investissement, mais aussi les agences de notation. Les acteurs de ce système parallèle canalisent l’épargne et accomplissent l’intermédiation des fonds au profit de projets d’investissement risqués, et ce, partout dans le monde. Même s’il remplit les mêmes fonctions d’intermédiation que le secteur bancaire régulé, le système bancaire parallèle fonctionne, dans son ensemble, sans réglementation systématique : il est en dehors du système de protection des dépôts et n’a pas accès aux facilités de liquidité fournies par la banque centrale qui est le «prêteur en dernier ressort». Depuis le début de la crise, la part du système parallèle a diminué. Elle reste cependant très importante. En 2010, elle était de 16.000 milliards de $ contre 13.000 milliards de $ pour le secteur réglementé.
Leçon 2. Les techniques de gestion du risque utilisées par les institutions financières assurent une protection effective contre les risques dans des conditions de marché normales, mais ne les prémunissent pas contre des risques extrêmes qui peuvent frapper toutes les institutions financières simultanément. La réaction des institutions à ces évènements extrêmes peut conduire à des ventes d’actifs, ce qui contribue à amplifier les risques.
Leçon 3. Dans un système financier globalisé, une crise systémique (c’est-à-dire susceptible de provoquer un effondrement global du système financier par le biais d’effets-dominos, de faillites en chaîne, etc.) peut donner lieu à des pertes qui excèdent la capacité fiscale d’un pays. C’est un défi majeur pour une régulation bancaire organisée sur une base nationale.
Leçon 4. Le risque systémique peut provenir de décisions décentralisées d’investisseurs et d’institutions financières qui cherchent à réduire les risques qui les affectent directement. Ce processus est souvent nourri par des politiques économiques conduisant les agents privés à adopter des stratégies similaires aggravant le risque systémique.
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Anderson, Ronald. "Numéro 96 - juin 2012." Regards économiques, October 12, 2018. http://dx.doi.org/10.14428/regardseco2012.06.01.
Full textAbstract:
Partant du constat que toutes les crises financières se ressemblent (endettement excessif, vente panique d’actifs, etc.), je cherche à déterminer ce qui caractérise la crise financière de 2007. Je passe en revue les étapes du développement de la crise, depuis les premiers signaux d’alerte sur le marché du crédit hypothécaire nord-américain jusqu’à la crise des dettes souveraines de l’Eurozone. Je relève quatre leçons majeures qui, selon moi, devraient être attentivement étudiées par tous ceux qui s’intéressent à la gestion des institutions financières majeures, à la définition de nouvelles règles prudentielles pour les banques et à la conception des politiques budgétaires et monétaires.
Leçon 1. L’économie globalisée s’appuie sur un secteur financier qui est lui-même globalisé. La santé de l’ensemble des banques au niveau mondial est profondément liée à l’ensemble du système financier. En particulier, les liens entre les banques et ce que l’on peut appeler le système bancaire parallèle (shadow banking sector) sont très nombreux. Par système bancaire parallèle, on entend notamment les compagnies d’assurances, les fonds de pension, les fonds d’investissement, mais aussi les agences de notation. Les acteurs de ce système parallèle canalisent l’épargne et accomplissent l’intermédiation des fonds au profit de projets d’investissement risqués, et ce, partout dans le monde. Même s’il remplit les mêmes fonctions d’intermédiation que le secteur bancaire régulé, le système bancaire parallèle fonctionne, dans son ensemble, sans réglementation systématique : il est en dehors du système de protection des dépôts et n’a pas accès aux facilités de liquidité fournies par la banque centrale qui est le «prêteur en dernier ressort». Depuis le début de la crise, la part du système parallèle a diminué. Elle reste cependant très importante. En 2010, elle était de 16.000 milliards de $ contre 13.000 milliards de $ pour le secteur réglementé.
Leçon 2. Les techniques de gestion du risque utilisées par les institutions financières assurent une protection effective contre les risques dans des conditions de marché normales, mais ne les prémunissent pas contre des risques extrêmes qui peuvent frapper toutes les institutions financières simultanément. La réaction des institutions à ces évènements extrêmes peut conduire à des ventes d’actifs, ce qui contribue à amplifier les risques.
Leçon 3. Dans un système financier globalisé, une crise systémique (c’est-à-dire susceptible de provoquer un effondrement global du système financier par le biais d’effets-dominos, de faillites en chaîne, etc.) peut donner lieu à des pertes qui excèdent la capacité fiscale d’un pays. C’est un défi majeur pour une régulation bancaire organisée sur une base nationale.
Leçon 4. Le risque systémique peut provenir de décisions décentralisées d’investisseurs et d’institutions financières qui cherchent à réduire les risques qui les affectent directement. Ce processus est souvent nourri par des politiques économiques conduisant les agents privés à adopter des stratégies similaires aggravant le risque systémique.