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See detailDiurnal thermosphere scale height from MEX/SPICAM grazing limb data
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Bougher, S et al

Conference (2014, July 01)

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See detailThe diurnal variation of NO, N(D-2), and ions in the thermosphere - A comparison of satellite measurements to a model
Rusch, D. W.; Gérard, Jean-Claude ULg; Fesen, C. G.

in Journal of Geophysical Research (1991), 96

A data base of parameters important to understanding the diurnal variation of odd-nitrogen and ions in the thermosphere near equinox, at low latitudes, and for quiet geomagnetic conditions is presented ... [more ▼]

A data base of parameters important to understanding the diurnal variation of odd-nitrogen and ions in the thermosphere near equinox, at low latitudes, and for quiet geomagnetic conditions is presented. The data base includes profiles of the odd-nitrogen species NO and N(D-2), the ions NO(+), O2(+), O(+), N2(+), and N(+); the total ion density; O and N2; and the neutral, ion, and electron temperatures. The measured time-dependent variations of NO, N(D-2), O2(+), and NO(+) compare favorably to the results of a time-dependent, photochemical, diffusion model for odd-nitrogen and ion chemistry. In particular, the model reproduces the rapid increase in NO density in the morning hours, the midafternoon maximum, and the late afternoon decrease. The model also reproduces the measured absolute densities for NO to within 20 percent over most of the diurnal cycle but falls below the measured density by as much as a factor of two in the late afternoon. [less ▲]

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See detailDiurnal variations of plasma FSH, LH, and testosterone in male ring doves kept under different photoperiods.
Balthazart, Jacques ULg; Reboulleau, C.; Cheng, M. F.

in General and Comparative Endocrinology (1981), 44(2), 202-6

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See detailDiurnal variations of plasma gonadotrophins in male domestic ducks during the sexual cycle.
Balthazart, Jacques ULg; Hendrick, J. C.; Deviche, P.

in General and Comparative Endocrinology (1977), 32(4), 376-89

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See detailDiurnal variations of sexual receptivity in the female Japanese quail (Coturnix coturnix japonica).
Delville, Y.; Sulon, J.; Balthazart, Jacques ULg

in Hormones and Behavior (1986), 20(1), 13-33

A series of experiments was performed to study the changes during the day of female receptivity in Japanese quail. In each experiment, the frequency of squatting and the percentage of male approaches ... [more ▼]

A series of experiments was performed to study the changes during the day of female receptivity in Japanese quail. In each experiment, the frequency of squatting and the percentage of male approaches which were followed by squatting increased at the end of the day, approximately 11 to 13 hr after lights on (in a photoperiod of 16L:8D). In some cases this increased receptivity was associated with a significant decrease of the long-avoid frequency. Analyses are presented which demonstrate that the increased receptivity at the end of the day is not directly caused by the oviposition and does not result directly from changes in the behavior of the male stimuli. This is strongly supported by the observation that the increase in receptivity was observed at the same time after lights on (but different clock times) in two groups of females which were raised in two different photoperiods shifted by 6 hr and tested with the same group of males raised in one of the two photoperiods. The increase in receptivity coincides with an increase in plasma estradiol and progesterone. Considering that this behavior is suppressed by ovariectomy, it is argued that the daily changes in receptivity could be controlled by the hormonal changes associated with the ovulatory cycle. [less ▲]

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See detailDIVA Graphical User Interface
Troupin, Charles ULg; Sirjacobs, Damien ULg; Beckers, Jean-Marie ULg

Conference (2006, November 13)

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See detailDIVA-4.2.1: presentation of the new features
Troupin, Charles ULg; Machín, Francisco; Ouberdous, Mohamed ULg et al

Poster (2008, April 03)

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See detailDIVA: a Data Analysis Software with Generalized-Cross Validation and Quality Control
Troupin, Charles ULg; Rixen, Michel; Sirjacobs, Damien ULg et al

Poster (2007, May 19)

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See detailDIVA: new features
Beckers, Jean-Marie ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

Scientific conference (2009, October 23)

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See detaildivand-1.0: n-dimensional variational data analysis for ocean observations
Barth, Alexander ULg; Beckers, Jean-Marie ULg; Troupin, Charles ULg et al

in Geoscientific Model Development (2014), 7

A tool for multidimensional variational analysis (divand) is presented. It allows the interpolation and analysis of observations on curvilinear orthogonal grids in an arbitrary high dimensional space by ... [more ▼]

A tool for multidimensional variational analysis (divand) is presented. It allows the interpolation and analysis of observations on curvilinear orthogonal grids in an arbitrary high dimensional space by minimizing a cost function. This cost function penalizes the deviation from the observations, the deviation from a first guess and abruptly varying fields based on a given correlation length (potentially varying in space and time). Additional constraints can be added to this cost function such as an advection constraint which forces the analysed field to align with the ocean current. The method decouples naturally disconnected areas based on topography and topology. This is useful in oceanography where disconnected water masses often have different physical properties. Individual elements of the a priori and a posteriori error covariance matrix can also be computed, in particular expected error variances of the analysis. A multidimensional approach (as opposed to stacking 2-dimensional analysis) has the benefit of providing a smooth analysis in all dimensions, although the computational cost is increased. Primal (problem solved in the grid space) and dual formulations (problem solved in the observational space) are implemented using either direct solvers (based on Cholesky factorization) or iterative solvers (conjugate gradient method). In most applications the primal formulation with the direct solver is the fastest, especially if an a posteriori error estimate is needed. However, for correlated observation errors the dual formulation with an iterative solver is more efficient. The method is tested by using pseudo observations from a global model. The distribution of the observations is based on the position of the ARGO floats. The benefit of the 3-dimensional analysis (longitude, latitude and time) compared to 2-dimensional analysis (longitude and latitude) and the role of the advection constraint are highlighted. The tool divand is free software, and is distributed under the terms of the GPL license (http://modb.oce.ulg.ac.be/mediawiki/index.php/divand). [less ▲]

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See detailDivergence of function and regulation of class B floral organ identity genes.
Samach, A.; Kohalmi, S. E.; Motte, Patrick ULg et al

in Plant Cell (1997), 9(4), 559-70

Regulatory mechanisms controlling basic aspects of floral morphogenesis seem to be highly conserved among plant species. The class B organ identity genes, which are required to establish the identity of ... [more ▼]

Regulatory mechanisms controlling basic aspects of floral morphogenesis seem to be highly conserved among plant species. The class B organ identity genes, which are required to establish the identity of organs in the second (petals) and third (stamens) floral whorls, are a good example of such conservation. This work compares the function of two similar class B genes in the same genetic background. The DEFICIENS (DEF) gene from Antirrhinum, including its promoter, was transformed into Arabidopsis and compared in function and expression with the Arabidopsis class B genes APETALA3 (AP3) and PISTILLATA (PI). The DEF gene was expressed in the second, third, and fourth whorls, as was PI. Functionally, DEF could replace AP3 in making petals and stamens. The DEF gene's AP3-like function and PI-like expression caused transformation of fourth-whorl carpels to stamens. Like AP3, all aspects of DEF function in Arabidopsis required a functional PI protein. Surprisingly, DEF could not replace the AP3 protein in properly maintaining AP3 transcripts (autoregulation). Our data allow us to revise the current model for class B autoregulation and propose a hypothesis for the evolution of class B gene expression in dicotyledonous plants. [less ▲]

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See detailDivergences et convergences des politiques d'intégration dans la Belgique multinationale. Le cas de parcours d'intégration pour les immigrés
Martiniello, Marco ULg; Ilke, Adam

in Revue Européenne des Migrations Internationales (2013), 29(2), 77-93

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See detailDivergences institutionelles et convergences mimétiques
Renard, Hugues ULg; Petit Jean, Maxime

Conference (2012, July)

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See detailDivergences morphologiques et génétiques chez une espèce de demoiselle (Pomacentridae): Pomacentrus coelestis
Frederich, Bruno ULg; Liu, Shang-Yin

Conference (2012, March 30)

La différentiation des populations est l’un des principaux thèmes de la biologie de l’évolution. Mise à part l’étude des variations des patrons de coloration, très peu d’études concernent les divergences ... [more ▼]

La différentiation des populations est l’un des principaux thèmes de la biologie de l’évolution. Mise à part l’étude des variations des patrons de coloration, très peu d’études concernent les divergences morphologiques entre les populations de poissons des récifs coralliens. Dans ce travail, nous avons étudié la différentiation morphologique et génétique entre plusieurs populations de l’espèce de demoiselle, Pomacentrus coelestis Jordan & Starks, 1901, dans le Nord-Ouest de l’océan Pacifique. Cette espèce, inféodée aux récifs coralliens, se nourrit principalement de zooplancton. Elle est particulièrement abondante dans cette région du monde. Les formes des mâchoires buccales (c’est-à-dire la mandibule et le prémaxillaire) ont été étudiées au moyen des méthodes de morphométrie géométrique et la structure génétique des populations a été caractérisée au moyen de cinq microsattelites (POM3, POM2, AC1578, Pom2269 et Pom2416). Différents tests statistiques ont révélé une variation significative de forme entre les populations de P. coelestis pour chacune des deux pièces squelettiques. Les variations de forme de la mandibule et du prémaxillaire apparaissent non-corrélées. Les variations morphologiques de la mandibule accompagne une rupture génétique entre des populations de l’île principale du Japon et les îles d’Okinawa et Taiwan. Cependant, les tests de Mantel et Procrustes n’ont révélé aucune congruence entre les structures génétiques et morphologiques. Des variables géographiques telles que la latitude, la longitude et les distances kilométriques expliquent peu ou pas les variances morphologiques observées. Dans notre discussion, nous illustrons que la plasticité phénotypique serait un mécanisme évolutif potentiel sous-jacent à la différence de formes entre les populations de P. coelestis. Cependant l’hypothèse d’une divergence adaptative ne pourrait cependant pas être exclue vu que nous avons uniquement étudié des marqueurs génétiques neutres (microsattelites). Une approche écomorphologique suggère que des régimes alimentaires différents pourraient être liés aux variations de forme des mâchoires buccales. A titre d’exemple, les individus des populations de l’île principale du Japon ont des mandibules plus massives suggérant des activités de broutage et/ou de morsure plus fréquentes. Inversément, les individus de Taiwan et d’Okinawa arborent un processus ascendant du prémaxillaire proportionellement plus long que les poissons des autres populations. Cette caractéristique, directement liée à l’efficacité de protrusion des mâchoires supérieures, confirmerait un degré de zooplanctonophagie plus élevé chez ces deux populations. [less ▲]

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See detailDiverse assemblages of Mid Devonian megaspores from Libya
Steemans, Philippe ULg; Breuer, Pierre; Petus, Elodie ULg et al

in Review of Palaeobotany and Palynology (2011), 165

[en] A restudy of Devonian palynological assemblages of samples from the A1-69 borehole, drilled in the Ghadamis Basin, western Libya, North Africa has led to the discovery of numerous well-preserved ... [more ▼]

[en] A restudy of Devonian palynological assemblages of samples from the A1-69 borehole, drilled in the Ghadamis Basin, western Libya, North Africa has led to the discovery of numerous well-preserved megaspores amongst abundant miospores, rare acritarchs and rare chitinozoans. Thirteen samples from base to top, 1496 ft (456 m) up to 965 ft (294 m), contain the richest Devonian megaspore assemblages from northwestern Gondwana. The section is dated by a rich diverse miospore assemblage indicating the presence of the upper part of the AD pre-Lem Biozone up to the lower part of the TCo Oppel Zone, ranging from a latest Eifelian or earliest Givetian age up to a latest Givetian or an earliest Frasnian age. Seventeen megaspore taxa have been identified. Among them, two new species (Biharisporites lugardonii and Lagenicula milleri) and four new varieties (Corystisporites acutispinosus var. acutispinosus and var. bullatus, Heliotriletes longispinosus var. longispinosus and var. radiatus) are described. One new possible megaspore species is also described: Verruciretusispora labiosa sp. nov. One core sample (1293 ft, 394 m) contains several specimens of very large megaspores (ca. 1 mm), the largest known from Devonian localities (except for one specimen observed in the Givetian from Belgium). Among the 17 megaspore taxa from Libya, 6 are present on the Euramerican Continent. This observation is in accordance with previous palynological conclusions that favour the absence of palaeogeographic barriers between the Euramerican and Gondwanan continents that are suggested to be grouped together in a “Pre-Pangea” land mass. [less ▲]

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See detailDiverse phenotypic profile of uterine tumors resembling ovarian sex cord tumors: an immunohistochemical study of 12 cases.
de Leval, Laurence ULg; Lim, Gkeok Stzuan Diana; Waltregny, David ULg et al

in American Journal of Surgical Pathology (2010), 34(12), 1749-61

BACKGROUND: Uterine tumors resembling ovarian sex cord tumors (UTROSCTs) are rare neoplasms thought to be of putative endometrial stromal origin and solely composed of sex cord elements. Our study aimed ... [more ▼]

BACKGROUND: Uterine tumors resembling ovarian sex cord tumors (UTROSCTs) are rare neoplasms thought to be of putative endometrial stromal origin and solely composed of sex cord elements. Our study aimed to delineate the immunophenotype of these tumors and to verify whether their morphology reflects true sex cord-like differentiation. DESIGN: Representative paraffin blocks from 12 UTROSCTs were selected after confirmation of the diagnosis. Cords and/or trabeculae were seen in all tumors, whereas tubules, diffuse areas, and a retiform pattern were present in 9, 6, and 2 cases, respectively. Tumors were stained for sex cord (inhibin, calretinin, WT1, and melan-A), epithelial (KL1 and epithelial membrane antigen), and smooth muscle markers (smooth muscle actin, desmin, smooth muscle myosin heavy chain, h-caldesmon, and histone deacetylase-8), CD10, HMB45, S100, and CD117. Intensity and percentage of staining were recorded. RESULTS: Six out of 12 tumors were positive for sex cord markers (inhibin 3 of 12, calretinin 4 of 12, WT1 4 of 12, and melan-A 3 of 11) with 4 tumors coexpressing more than one marker. Half of the UTROSCTs showed positivity for KL1, with 2 tumors coexpressing epithelial membrane antigen. All but one tumor expressed one or more smooth muscle markers, with smooth muscle actin, desmin and histone deacetylase-8 being most commonly expressed. CD10 was positive in 6 of 12 tumors, CD117 in 4 of 12, and S100 in 2 of 11 tumors, whereas HMB45 was negative in 11 tumors tested. CONCLUSIONS: UTROSCTs have a diverse immunohistochemical profile often coexpressing sex cord, epithelial, and smooth muscle markers. The expression of smooth muscle markers in these tumors does not imply a smooth muscle origin as endometrial and sex cord stromal tumors are not infrequently positive for these markers. Positivity for sex cord markers supports a true sex cord/steroid phenotype. Although the immunohistochemical profile of these tumors overlaps with that of endometrial stromal tumors with sex cord-like differentiation as well as ovarian sex cord stromal tumors, the origin of UTROSCT remains uncertain. [less ▲]

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See detailDiverses méthodes de philosophie avec les enfants
Herla, Anne ULg

Conference given outside the academic context (2007)

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See detailDiversidad genética del Virus de la Leucemia Bovina: una aproximación filogenética
Rodriguez, Sabrina ULg; Trono, K.; Jones, L.R.

Poster (2008, September 22)

Diversidad genética del Virus de la Leucemia Bovina: una aproximación filogenética Sabrina M. Rodríguez1, Karina Trono1, Leandro R. Jones2 1 Instituto de Virología, CICVyA, INTA-Castelar. C.C. 77. C.P ... [more ▼]

Diversidad genética del Virus de la Leucemia Bovina: una aproximación filogenética Sabrina M. Rodríguez1, Karina Trono1, Leandro R. Jones2 1 Instituto de Virología, CICVyA, INTA-Castelar. C.C. 77. C.P. 1712. Castelar, Buenos Aires, Argentina. 2 Estación de Fotobiología Playa Unión. C.C. 15. C.P. 9103. Rawson, Chubut, Argentina. *E-mail: srodriguez@cnia.inta.gov.ar El virus de la leucemia bovina (BLV), agente etiológico de la Leucemia Bovina Enzoótica (LBE), pertenece al género Deltaretrovirus, dentro de la familia Retroviridae. En Argentina, la infección por BLV presenta niveles de seroprevalencia individual del 32,8% y del 84% a nivel predial. En trabajos anteriores, las cepas de BLV han sido clasificadas en dos grupos: uno Europeo y otro que incluye cepas de Japón y Estados Unidos (USA). En dos trabajos mas recientes se observo que la mayoría de las cepas argentinas se agrupan en un clado, mientras que una proporción minoritaria se agrupa con cepas de diverso origen. En uno de estos trabajos se propuso la existencia de cuatro genogrupos (Clusters I a IV), uno de los cuales (Cluster II) seria exclusivo de Argentina. Estas clasificaciones fueron propuestas en base a análisis realizados a partir de matrices de distancias obtenidas a partir de secuencias parciales (444/1547 pb.) del gen env. Las distancias fueron calculadas asumiendo el modelo evolutivo de Kimura con dos parámetros (K2P) y los árboles se obtuvieron mediante el algoritmo Neighbor-Joining (NJ). Actualmente, existen métodos específicos y objetivos para la selección de modelos evolutivos. Se ha demostrado que el uso de modelos arbitrarios puede conducir a resultados inesperados y erróneos. Por otro lado, el algoritmo NJ ha sido ampliamente superado por métodos más exhaustivos y modernos cómo Parsimonia y Máxima Verosimilitud. En este trabajo se caracterizaron 28 provirus argentinos mediante la secuenciación del gen env (1333/1547 pb.). Estas secuencias, junto con otras 42 secuencias seleccionadas de forma tal de abarcar toda la diversidad conocida y de incluir representantes de la mayor cantidad posible de locaciones geográficas, fueron analizadas mediante Parsimonia con el objeto de examinar las clasificaciones previas. Como outgroup (OG), se utilizaron secuencias homólogas de HTLV-1, HTLV-2, STLV-1 y STLV-2. Las secuencias fueron alineadas usando el programa Muscle 3.6. Los alineamientos fueron analizados con el programa TNT 1.1, mediante el cual se realizaron 1000 adiciones al azar (RAS) seguidas de Tree Bisection Reconection (TBR). La estimación del soporte de los grupos identificados se realizó mediante Symetric Jackniffing, utilizando el programa TNT. Nuestros resultados soportan la existencia del clado de secuencias de Japón y USA. Los árboles obtenidos en este trabajo no apoyan ni contradicen el grupo europeo, ya que el mismo podría estar presente en algunas de las posibles resoluciones del árbol sin raíz. Las secuencias de Argentina no se ubicaron en un único grupo sino que se mezclaron con cepas de diverso origen. Nuestros resultados no soportaron la hipótesis de que exista regionalización de las cepas de BLV, tal como se ha observado en HTLV. El árbol consenso de los árboles derivados del análisis incluyendo el outgroup, presentó una resolución relativamente baja con respecto al árbol consenso derivado del análisis sin raíz. Esto parece deberse a que las secuencias utilizadas como outgroup son extremadamente divergentes con respecto al ingroup, lo cual queda en evidencia luego de una simple inspección visual del correspondiente alineamiento. El resultado de esto es que muchas regiones de la matriz constituyen alineamientos al azar (es decir asignaciones de homología primaria incorrectas y aleatorias), con la consecuente pérdida de información. Esta última observación es de particular interés dado que HTLV y STLV han sido utilizados como OG en una gran cantidad de trabajos, lo cual está justificado ya que son los grupos conocidos más próximos a BLV. Nuestros análisis, sin embargo, sugieren fuertemente que es necesario identificar outgroups más adecuados para lograr una comprensión más acabada de la diversidad de estos virus. [less ▲]

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See detailDiversidad genética molecular de Mirabilis expansa mediante RAPD
Chia, J. W.; Lopez, C. B.; Blas, R. et al

in Ecologia Aplicada (2006), 5(1,2), 81-86

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See detailDe diversificatie van de Belgische verscheidenheid
Martiniello, Marco ULg

in Martiniello, Marco; Swyngedouw, Marc (Eds.) Belgische Toestanden. De lotgevallen van een kleine bi-culturele democratie (1998)

Detailed reference viewed: 8 (0 ULg)