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See detailA distinctive marginal marine palynological assemblage from the Pridoli of Northwestern Saudi Arabia
Al-Hajri, S.; Verniers, J.; Paris, F. et al

Conference (2008)

This paper describes a rare occurrence of a rich and diverse palynological assemblage from a controversial stratigraphic unit in well EW8 in northwestern Saudi Arabia. The composition of this assemblage ... [more ▼]

This paper describes a rare occurrence of a rich and diverse palynological assemblage from a controversial stratigraphic unit in well EW8 in northwestern Saudi Arabia. The composition of this assemblage strongly suggests a Pridoli age and therefore it is referred here to the Tawil Formation. The assemblage encountered contains very characteristic chitinozoans, acritarchs, tasmanities, scolecodontsm, eurypterid cuticle and common land-derived miospores and hilate cryptospores. Chitinozoans such as Margachitina elegans, Ancyrochitina fragilis brevis, Ancyrochitina fragilis, Sphaerochitina sphaerocephala, Urnochitina urna, Pseudochlathrochitina carmenchui and Lagenochitina brevicollis confer the Pridoli age assignment. This assemblage of chitinozoans correlates very well with Assemblage D from the Alternances Gréso-Argileuses Formation of the A1-61 well in northwestern Libya. Among the acritarchs present are: Cymbosphaeridium pilar, Leoniella carminae,Diexallophasis spp., Tunisphaeridium cf caudatum, Leiofusa estrecha and Eupoikilofusa striatifera. <br /> <br />Furthermore, the join occurrence of U. urna, P. carmenchui and M. elegans is clearly indicative of the middle part of the Pridoli as in the Libyan well A1-61, and in many wells in Algeria. This corresponds to what is considered to be a transgressive mid Pridoli event in the Algerian Sahara, with non marine intervals bracketing this brief marine sea level rise. This event is likely to have extended into all of north Gondwana including Arabia. [less ▲]

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See detailDISTINGUISHEDNESS OF WEIGHTED FRECHET SPACES OF CONTINUOUS-FUNCTIONS
Bastin, Françoise ULg

in Proceedings Of The Edinburgh Mathematical Society (1992), 35(Part 2), 271-283

In this paper, we prove that if U is an increasing sequence of strictly positive and continuous functions on a locally compact Hausdorff space X such that VBAR congruent-to VBAR and C(X), then the Frechet ... [more ▼]

In this paper, we prove that if U is an increasing sequence of strictly positive and continuous functions on a locally compact Hausdorff space X such that VBAR congruent-to VBAR and C(X), then the Frechet space CU(X) is distinguished if and only if it satisfies Heinrich's density condition, or equivalently, if and only if the sequence U satisfies condition (H) (cf. e.g.`[1] for the introduction of (H)). As a consequence, the bidual lambda(infinity)(A) of the distinguished Kothe echelon space lambda-0(A) is distinguished if and only if the space lambda-1(A) is distinguished. This gives counterexamples to a problem of Grothendieck in the context of Kothe echelon spaces. [less ▲]

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See detailDistinguishing the sites of pre-rRNA synthesis and accumulation in Ehrlich tumor cell nucleoli.
Thiry, Marc ULg; Goessens, Guy ULg

in Journal of Cell Science (1991), 99 ( Pt 4)

The precise location of transcribing rRNA genes within Ehrlich tumor cell nucleoli has been investigated using two approaches: high-resolution autoradiography of cells pulse-labelled with tritiated ... [more ▼]

The precise location of transcribing rRNA genes within Ehrlich tumor cell nucleoli has been investigated using two approaches: high-resolution autoradiography of cells pulse-labelled with tritiated uridine, varying the exposure time, and in situ-in vitro transcription coupled with an immunogold labelling procedure. When autoradiographic preparations are exposed for a short time, silver grains are found associated almost exclusively with interphasic cell nucleoli. Labelling of extranucleolar areas requires longer exposure. Within the nucleolus, the first sites to be revealed are in the dense fibrillar component. Prolonging exposure increases labelling over the dense fibrillar component, with label becoming more and more apparent over the fibrillar centers. Under these conditions, however, labelling does not extend into the granular component, and no background is observed. Initiation of transcription on ultrathin cell sections occurs preferentially at the borders of condensed chromatin blocks and in their close vicinity. The condensed chromatin areas themselves remain unlabelled. Inside most nucleoli, gold-particle clusters are mainly detected in the fibrillar centers, especially at their periphery, whereas the dense fibrillar component and the granular component remain devoid of label. These results, together with previous observations made on the same cell type, clearly indicate that the fibrillar centers are the sites of rRNA gene transcription in Ehrlich tumor cell nucleoli, while the dense fibrillar component is the site of pre-rRNA accumulation. [less ▲]

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See detailDistintas variantes naturales del BLV presentan patrones diferenciales de unión a factores celulares
Rodriguez, Sabrina ULg; Varone, C.; Mozgovoj, M. et al

Poster (2003, December 01)

DISTINTAS VARIANTES NATURALES DEL BLV PRESENTAN PATRONES DIFERENCIALES DE UNIÓN A FACTORES CELULARES. S. Rodriguez1, C. Varone2, M. Mozgovoj1, C. Gómez1, M.J. DusSantos1, A. Wigdorovitz1, E. Cánepa2, K ... [more ▼]

DISTINTAS VARIANTES NATURALES DEL BLV PRESENTAN PATRONES DIFERENCIALES DE UNIÓN A FACTORES CELULARES. S. Rodriguez1, C. Varone2, M. Mozgovoj1, C. Gómez1, M.J. DusSantos1, A. Wigdorovitz1, E. Cánepa2, K. Trono1 1Instituto de Virología, CICVyA, INTA – Castelar. 2Cátedra de Biologia Molecular, Facultad de Ciencias Exactas, UBA. Buenos Aires, Argentina. La relación entre el genotipo y las formas de manifestación patogénica está demostrada para ciertos Retrovirus, y las zonas regulatorias Long Terminal Repeats (LTR) han sido descriptas, entre otros factores, como portadoras de determinantes de patogenia. En el caso del Virus de la Leucosis Bovina (VLB), estudios previos de secuencias llevados a cabo en nuestro laboratorio sobre las zona R-U5 de las regiones genéticas provirales LTR aisladas de 36 animales infectados naturalmente y con diferentes formas de evolución revelaron la presencia de 4 cambios fijos y característicos de provirus aislados de linfosarcoma (LS)(100%), 1 en la región R y 3 en U5. Estas modificaciones están ausentes en la mayoría (16/22) de los provirus aislados de formas asintomáticas (AL/PL). La alta asociación entre los cambios de nucleótidos y las formas de patogenia demostró la existencia de una secuencia de nucleótidos consenso y propia de los aislados de LS en la región U5 del LTR del genoma proviral de VLB. Con el objetivo de analizar si existe una capacidad diferencial de reconocimiento de factores de regulación de la transcripción celular en la célula hospedadora de las secuencias LTRs de aislamientos de distintas formas de patogenia, se utilizaron ensayos de cambio en la movilidad electroforética (EMSA). La evaluación conjunta de los resultados demuestra que existirían diferencias específicas de unión de la región U5 a proteínas del complejo de regulación de la transcripción celular denominadas E2F en relación con las diferentes presentaciones de esta patología. Estos hallazgos aportan datos en relación con la caracterización de esta co-variación de nucleótidos como marcadores de patogenia del VLB, así como también representan un adelanto en el conocimiento de la patobiología del BLV. [less ▲]

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See detailDistopia e cecità: le mosche incantate di Paolo Volponi
Fichera, Gabriele ULg

in Ritrovato, Salvatore; Toracca, Tiziano (Eds.) Volponi estremo (2015)

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See detailLes distorsions de ségrégation chez les plantes et leurs conséquences sur l'amélioration génétique
Diouf, F.B.H.; Mergeai, Guy ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4), 499-508

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See detailDistorsions de ségrégation et amélioration génétique des plantes (synthèse bibliographique)
Diouf, Fatimata Bintou Hassédine ULg; Mergeai, Guy ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4)(499-508),

Distortion of allele segregation is a phenomenon common to all living organisms. Described as a great force of evolution, this phenomenon is caused by various genetic or physiological factors. Random or ... [more ▼]

Distortion of allele segregation is a phenomenon common to all living organisms. Described as a great force of evolution, this phenomenon is caused by various genetic or physiological factors. Random or not, the factors involved in segregation distortion have significant effects on crop improvement and on the mapping of crop genomes. Analysis of numerous results involving a distortion of the segregation of alleles was used to characterize partially the causes and effects of this phenomenon. The results obtained show that the importance of segregation distortion depends on the type of molecular markers used and the nature of the populations investigated. Further research is needed to better identify and locate the factors causing segregation distortion, and to better assess and to understand their effects. The development of dense genetic maps, combined with cytogenetic analysis, would allow rapid progress in this area. [less ▲]

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See detailThe Distorted Shape of Jupiter's North Auroral Oval - A Possible Magnetic Anomaly
Clarke, J. T.; Grodent, Denis ULg; Connerney, J.

Poster (2002)

Repeated imaging of Jupiter's aurora has shown that the northern main oval has a distorted "kidney bean" shape in the general range of 40-100 deg magnetic longitude, which appears unchanged since 1994 ... [more ▼]

Repeated imaging of Jupiter's aurora has shown that the northern main oval has a distorted "kidney bean" shape in the general range of 40-100 deg magnetic longitude, which appears unchanged since 1994. More recently, improved accuracy in locating the satellite footprint auroral emissions has provided new information about the geometry of Jupiter's magnetic field in this and other areas. The persistent pattern of the main oval implies a disturbance of the local magnetic field, and the increased latitudinal separation of the locus of satellite footprints from each other and from the main oval implies a locally weaker field strength. It is possible that these phenomena result from a magnetic anomaly in Jupiter's intrinsic magnetic field, as was proposed by A. Dessler in the 1970's. There is presently only limited evidence from the scarcity of auroral footprints observed in this longitude range. Similarly, while it is difficult to observe the conjugate regions in the southern aurora, there does not appear to be any corresponding distortion in the south. We will present the observational evidence that we have accumulated to date, propose future observations to determine the nature of this disturbance, and speculate on its causes and implications. [less ▲]

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See detailDistortion function and clustering for local linear models
Kerschen, Gaëtan ULg; Yan, Ai Min; Golinval, Jean-Claude ULg

in Journal of Sound & Vibration (2005), 280(1-2), 443-448

Principal component analysis (PCA) is a ubiquitous statistical technique for data analysis. PCA is however limited by its linearity and may sometimes be too simple for dealing with real-world data ... [more ▼]

Principal component analysis (PCA) is a ubiquitous statistical technique for data analysis. PCA is however limited by its linearity and may sometimes be too simple for dealing with real-world data especially when the relations among variables are nonlinear. Recent years have witnessed the emergence of nonlinear generalizations of PCA, as for instance nonlinear principal component analysis (NLPCA) [1] or vector quantization principal component analysis (VQPCA) [2]. VQPCA involves a two-step procedure, namely a clustering of the data space into several regions and the application of PCA in each local region. In Ref. [3], VQPCA was applied for the reconstruction of dynamical response and it was shown that it is potentially a more effective tool than conventional PCA. The purpose of this technical note is to further investigate VQPCA and to have a closer look at the choice of the distortion function used for clustering the data space. [less ▲]

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See detailDistortion-Invariant FOPEN Detection Filter Improvements
Casasent, David P.; Ippolito, K.; Verly, Jacques ULg

Conference (1999, April)

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See detailDistrait? Agité? Mon enfant présente-t-il un trouble déficitaire de l'attention avec/sans hyperactivité?
Catale, Corinne ULg

Conference given outside the academic context (2012)

La Clinique Psychologique et Logopédique Universitaire (CPLU) a le plaisir de vous inviter à sa prochaine conférence donnée par Corinne Catale (Docteur en Sciences Psychologiques) Le diagnostic du trouble ... [more ▼]

La Clinique Psychologique et Logopédique Universitaire (CPLU) a le plaisir de vous inviter à sa prochaine conférence donnée par Corinne Catale (Docteur en Sciences Psychologiques) Le diagnostic du trouble déficitaire de l'attention chez l'enfant reste encore très complexe. L'exposé aura comme premier objectif de décrire le fonctionnement cognitif des enfants atteints de ce trouble et ses conséquences sur la vie quotidienne. Ensuite, nous montrerons l'intérêt de la neuropsychologie dans son diagnostic, mais également dans sa prise en charge, avec la mise en place d'une remédiation cognitive personnalisée et focalisée sur les difficultés que l'enfant présente. [less ▲]

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See detailDistribución de tasas evolutivas en plantas vasculares entre el Silúrico y el Pleistoceno
Cascales - Miñana, Borja ULg; Ruiz-Sánchez, Francisco J.

in Cambra-Moo, O.; Martínez-Pérez, C.; Chamero, B. (Eds.) et al Cantera Paleontológica (2007)

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See detailDistribución geográfica y relaciones genéticas del género Arracacia Bancroft en el Perú
Blas Sevillano, R.; Arbizu, C.; Baudoin, Jean-Pierre ULg

Conference given outside the academic context (2004)

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See detailA distributed algorithm for weighted max-min fairness in MPLS networks
Skivée, Fabian ULg; Leduc, Guy ULg

in Lecture Notes in Computer Science (2004, August), 3124

We propose a novel distributed algorithm to achieve a weighted max-min sharing of the network capacity. We present the Weight Proportional Max-Min policy (WPMM) that supports a minimal rate requirement ... [more ▼]

We propose a novel distributed algorithm to achieve a weighted max-min sharing of the network capacity. We present the Weight Proportional Max-Min policy (WPMM) that supports a minimal rate requirement and an optional maximal rate constraint and allocates network bandwidth among all aggregates based on a weight associated with each one. Our algorithm achieves this policy for IP/MPLS networks using the RSVP-TE signalling protocol. It uses per-LSP accounting in each node to keep track of the state information of each LSP. It uses a novel explicit bottleneck link strategy and a different control architecture in which we update the control packet in the forward path. Simulations show that these two elements improve substantially the convergence time compared to algorithms designed for ATM networks. [less ▲]

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See detailDistributed Collaborative Design Studio : a sketch-based environment to support rich distant collaboration. Workshop.
Safin, Stéphane ULg; Delfosse, Vincent ULg; Elsen, Catherine ULg et al

Conference (2008)

An increasing number of large scale projects requires that distant teams collaborate together remotely. At the same time, the current CAD tools only offer minimal support for partial and asynchronous ... [more ▼]

An increasing number of large scale projects requires that distant teams collaborate together remotely. At the same time, the current CAD tools only offer minimal support for partial and asynchronous interactions. The application we propose enables full synchronous and remote sketch-based collaborative design. This setup is a combination of a virtual desktop (a remote meeting table), a standard videoconference system, a gesture recognition module and a networked, real-time, collaborative drawing software (SketSha). The solution as a whole is multimodal in essence (gestures, speech, drawing…) supporting immersive remote collaborative design. [less ▲]

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See detailDistributed computing as a new opportunity for stakeholders in dairy cattle management and breeding
Gengler, Nicolas ULg

in Berckmans, D; Vandermeulen, J (Eds.) Precision Livestock Farming ‘13 (2013)

Currently the uses of on-farm computers and of centralized performance-recording based tools are considered as two opposite models for dairy management. However, dividing the problem into complementary ... [more ▼]

Currently the uses of on-farm computers and of centralized performance-recording based tools are considered as two opposite models for dairy management. However, dividing the problem into complementary tasks, each of which is optimally solved, is an opportunity that should also be considered by stakeholders. recent development solved data exchange issues allowing the use of adapted distributed computing algorithms. as example milk yield and composition are given. Different research projects and several commercial companies are focussing on the development of on-farm tools, mostly near infrared (nir) based, other projects are developing and implementing tools based on mid infrared (mir), available only through performance recording.Both are complementary, as nir based measurements are easier and less expensive, available at every milking, but mir based measurements are more precise, however only obtained every 4 weeks. numerous advantages arise when combining both types of measurements. it will be shown that statistical theory exists to base advanced modelling on, using optimally the longitudinal data generated by this type of setting. this will open different novel opportunities to optimize currently used on-farm and off-farm management and breeding tools. [less ▲]

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See detailDistributed control of electromechanical oscillations in very large-scale electric power systems
Wang, Da ULg

Doctoral thesis (2014)

Electromechanical oscillations threaten the secure operation of power systems and if not controlled efficiently can lead to generator outages, line tripping and even large-scale blackouts. Different ... [more ▼]

Electromechanical oscillations threaten the secure operation of power systems and if not controlled efficiently can lead to generator outages, line tripping and even large-scale blackouts. Different damping devices, like Power System Stabilizers (PSSs), Thyristor Controlled Series Compensators (TCSCs), and so on, are installed to damp these oscillations. This thesis proposes a trajectory-based supplementary control to improve damping effects of existing controllers, which treats damping control as a multi-step optimization control problem with discrete dynamics and costs. At each control time, it collects current system states, solves the optimal control problem and superimposes the calculated supplementary inputs on the outputs of existing damping controllers, in order to enhance the damping. These supplementary signals are continuously updated, which allows to adaptively adjust and coordinate a subset of existing damping controllers, and eventually all of them. Two kinds of methods, Model Predictive Control (MPC) and Reinforcement Learning (RL), are used to embody the proposed supplementary damping control. Firstly, a fully centralized MPC scheme is designed based on a linearized, discrete, complete state space model. Its performances are evaluated both in ideal conditions and considering realistic state estimation errors, and computation and communication delays. The effects of the number and type of available damping controllers are also studied. This scheme is further extended into a distributed scheme with the aim of making it more viable for very large-scale or multi-area systems. Different ways of decoupling and coordinating between subsystems are analyzed. Finally, a robust hierarchical multi-area MPC scheme is proposed, introducing a second layer of MPC based controllers at the level of individual power plants and transmission lines. Secondly, a tree-based batch mode RL algorithm is applied to carry on the proposed supplementary damping control. Using a set of dynamic and reward four-tuples, it constructs an approximation of the optimal $Q$-function over a given temporal horizon. The actions greediest with respect to the $Q$-function are applied as supplementary signals to existing damping controllers. The scheme is firstly tested on a single generator, and then on multiple generators. Different reward signals and damping levels are also considered. Finally, the combined control effects of MPC and RL are investigated. [less ▲]

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See detailDistributed Dynamic Load Balancing for Iterative-Stencil Applications
Dethier, Gérard ULg; Marchot, Pierre ULg; de Marneffe, Pierre-Arnoul ULg

in Cracow Grid Workshop '08 Proceedings (2009, March)

In the context of jobs executed on heterogeneous clusters or Grids, load balancing is essential. Indeed, a slow machine must receive less work than a faster one otherwise the overall job termination will ... [more ▼]

In the context of jobs executed on heterogeneous clusters or Grids, load balancing is essential. Indeed, a slow machine must receive less work than a faster one otherwise the overall job termination will be delayed. This is particularly true for Iterative-Stencil Applications where tasks are run simultaneously and are interdependent. The problem of assigning coexisting tasks to machines is called mapping. With dynamic clusters (where the number of machines and their available power can change over time), dynamic mapping must be used. A new mapping must be calculated each time the cluster changes. The mapping calculation must therefore be fast. Also, a new mapping should be as close as possible to the previous mapping in order to minimize task migrations. Dynamic mapping methods exist but are based on iterative optimization algorithms. Many iterations are required to reach convergence. In the context of a distributed implementation, many communications are needed. We developed a new distributed dynamic mapping method which is not based on iterative optimization algorithms. Current results are encouraging. Load balancing execution time remains bounded for tested cluster sizes. Also, a decrease of ~20% of the global available computational power of a cluster leads to ~30% of migrated tasks during load rebalancing. A new mapping is therefore close to the previous one. [less ▲]

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See detailDistributed fiber-optic temperature sensing for hydrologic systems
Selker, John S.; Thévenaz, Luc; Huwald, Hendrik et al

in Water Resources Research (2006), 42(12), 12202

Instruments for distributed fiber-optic measurement of temperature are now available with temperature resolution of 0.01°C and spatial resolution of 1 m with temporal resolution of fractions of a minute ... [more ▼]

Instruments for distributed fiber-optic measurement of temperature are now available with temperature resolution of 0.01°C and spatial resolution of 1 m with temporal resolution of fractions of a minute along standard fiber-optic cables used for communication with lengths of up to 30,000 m. We discuss the spectrum of fiber-optic tools that may be employed to make these measurements, illuminating the potential and limitations of these methods in hydrologic science. There are trade-offs between precision in temperature, temporal resolution and spatial resolution, following the square root of the number of measurements made; thus brief, short measurements are less precise than measurements taken over longer spans in time and space. Five illustrative applications demonstrate configurations where the distributed temperature sensing (DTS) approach could be used: (1) lake bottom temperatures using existing communication cables, (2) temperature profile with depth in a 1400 m deep decommissioned mine shaft, (3) air-snow interface temperature profile above a snow-covered glacier (4) air-water interfacial temperature in a lake, and (5) temperature distribution along a first-order stream. In examples 3 and 4 it is shown that by winding the fiber around a cylinder, vertical spatial resolution of millimeters can be achieved. These tools may be of exceptional utility in observing a broad range of hydrologic processes including evaporation, infiltration, limnology, and the local and overall energy budget spanning scales from 0.003 to 30,000 m. This range of scales corresponds well with many of the areas of greatest opportunity for discovery in hydrologic science. [less ▲]

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