bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalization of the Ensemble Kalman Filter Using Kernels for Non-gaussian Random Fields
Authors: Sarma P. , Chen W. H. 
Published: February 2009

Abstract
Efficient history matching (model updating) of geologically complex reservoirs is important in many applications, but it is central in closed-loop reservoir modeling, in which real-time model updating is required. Within the context of closed-loop modeling, one history matching approach receiving the most attention to date is the ensemble Kalman filter (EnKF). Although the EnKF has many advantages such as ease of implementation and efficient uncertainty quantification, it is technically appropriate only for random fields (e.g., permeability) characterized by two-point geostatistics (multi-Gaussian random fields). Realistic systems however are much better described by multi-point geostatistics, which is capable of representing key geological structures such as channels. History matching algorithms that are able to reproduce realistic geology provide enhanced predictive capacity and can therefore lead to better reservoir management and optimization.
In this work, we propose and formulate a generalized EnKF using kernels, capable of representing non-Gaussian random fields characterized by multi-point geostatistics. The main drawback of the standard EnKF is that the Kalman update essentially results in a linear combination of the forecasted ensemble, and the EnKF only uses the covariance and cross-covariance between the random fields (to be updated) and observations, thereby only preserving two-point statistics. Kernel methods allow the creation of nonlinear generalizations of linear algorithms that can be exclusively written in terms of dot products. By deriving the EnKF in a high-dimensional feature space implicitly defined using kernels, both the Kalman gain and update equations are nonlinearized, thus providing a completely general nonlinear set of EnKF equations, the nonlinearity being controlled by the kernel. By choosing high order polynomial kernels, multi-point statistics and therefore geological realism of the updated random fields can be preserved. The procedure is applied to two example cases where permeability is updated using production data as obserations, and is shown to better reproduce complex geology compared to the standard EnKF, while providing reasonable match to the production data.
Continuous Reservoir Simulation Model Updating and Forecasting Using a Markov Chain Monte Carlo Method
Authors: Liu Chang , McVay Duane A. 
Published: February 2009

Abstract
Most reservoir simulation studies are conducted in a static context - at a single point in time using a fixed set of historical data for history matching. Time and budget constraints usually result in significant reduction in the number of unknown parameters and incomplete exploration of the parameter space, which results in underestimation of forecast uncertainty and less-than-optimal decision making. Markov Chain Monte Carlo (MCMC) methods have been used in static studies for rigorous exploration of the parameter space for quantification of forecast uncertainty, but these methods suffer from long burn-in times, and many required runs for chain stabilization.
In this paper, we apply MCMC in a real-time reservoir modeling application. The system operates in a continuous process of data acquisition, model calibration, forecasting, and uncertainty quantification. Since it operates continuously, over time many more realizations can be run than with traditional approaches. This allows more thorough investigation of the parameter space and more complete quantification of forecast uncertainty. The system was validated on the PUNQ synthetic reservoir in a simulated years-long, continuous modeling scenario and yielded probabilistic forecasts that narrow with time.
The continuous MCMC simulation approach allows generation of a reasonable probabilistic forecast at a particular point in time with many fewer models than the traditional application of the MCMC method in a one-time simulation study. It also provides a mechanism for calibrating uncertainty estimates over time.
Thermal Streamline Simulation for Hot Water Flooding
Authors: Zhu Z. , Gerritsen M. G. , Thiele M. R. 
Published: February 2009

Abstract
We explore the extension of streamline simulation (SL) to thermal recovery processes. For each global time step of the thermal streamline simulator, we first compute the pressure field on an Eulerian grid. We then solve for the advective parts of the mass balance and energy equations along individual streamlines. At the end of each global time step, we account for the nonadvective terms of the mass balance and energy equations on the Eulerian grid along with gravity. We included temperature dependent viscosity and account for thermal expansion. We tested the thermal streamline simulator on two-dimensional heterogeneous quarter five spot problems and compared the results with those computed by a commercial thermal simulator on both accuracy and efficiency. Sensitivity studies for compressibility, gravity and thermal conduction effects are presented. The thermal streamline simulator is capable of producing accurate results at a computational cost that is much lower than that of existing Eulerian simulators.
An Adaptive Continuum/Discontinuum Coupled Reservoir Geomechanics Simulation Approach for Fractured Reservoirs
Authors: Deisman Nathan , Chalaturnyk Richard J. , Mas Ivars Diego 
Published: February 2009

Abstract
Geomechanical effects during several stages of the reservoir life cycle are becoming more important in understanding the overall behaviour of the reservoir. Fractured reservoirs are generally recognized to be sensitive to changes in effective stress caused by production activities including production and injection processes. Using a reservoir simulation approach which incorporates geomechanical processes occurring in a fractured reservoir offers insight into reservoir management strategies. Some of the processes include changes in effective stress due to pressure depletion and/or thermal recovery, creation of new fractures, and changes in fracture apertures. All process effects influence fracture and matrix permeability and porosity and, in some cases can be identified by changes in acoustic properties and seismicity.
A reservoir simulation approach which attempts to capture all of these processes must link four simulation approaches in an adaptive nature. A reservoir simulator is used to represent the complex fluid flow processes found in thermal and multi component fluid reservoirs. A continuum geomechanical simulator is used to capture the effects of changes in reservoir pressure, temperature and fluid volumes on the effective stress field. A particle flow code with an embedded fracture network is applied to capture the changes in apertures, creation of new fractures, and dynamic geomechanical continuum properties as well as the acoustic response. A discrete fracture network program is used to create equivalent permeabilities and porosities, while accounting for changes in apertures and new formed fractures. All of these codes are coupled to capture the complex processes described above in adaptive reservoir continuum/discontinuum coupling.
MPD: Beyond Narrow Pressure Windows
Authors: Nauduri Sagar , Medley George H. , Schubert Jerome J. 
Published: February 2009

AbstractManaged Pressure Drilling (MPD) is an enabling technology that is highly sought after in the drilling industry in recent years. MPD is generally associated with narrow pressure windows, i.e., staying between either pore pressure (Pp) or formation stability and fracture pressure (Fp). However, operators are starting to realize MPD has a broader range of application, beyond navigating narrow pressure windows and other traditional applications such as Dual Gradient Drilling and Pressurized MudCap Drilling.Over the past couple of years, MPD's range of application has increased, as can be seen from the examples presented in this paper. New offshore and onshore MPD projects in the Gulf of Mexico (GoM), North Sea, North America, South America, Africa and Europe are being designed for objectives like improving Rate of Penetration (ROP), reducing formation invasion, validation of pore pressure data, reducing incidents of stuck pipe and mitigating the effects of differential sticking, reducing ballooning or hole breathing and minimizing Non-Productive Time (NPT).MPD is not a universal solution or panacea and improper application of the technique may ultimately cost more than conventional drilling methods. However, with comprehensive planning and execution by experienced engineers, MPD can help actualize project objectives that otherwise might be impossible with conventional techniques.
Ceramic Surface Polishing Techniques After Removal of Orthodontic Adhesive
Authors: de Alcântara Cury-Saramago Adriana , Coimbra Priscila Rocha , de Moraes Izquierdo Antonio , Elias Carlos Nelson , de Oliveira Ruellas Antônio Carlos , Sant'Anna Eduardo Franzotti 
Published: February 2009

Abstract
Objective: Verify the in vitro effectiveness of different porcelain surface polishing systems used after orthodontic debonding.
Materials and Methods: Restorations were simulated by 52 metallic samples covered with glazed feldspathic porcelain. Four of these intact samples composed the control group (C). The remaining samples were divided into four groups (n = 12), according to the surface preparation they were to receive: no surface treatment (G1); roughened with a diamond bur (G2); etched with 10% hydrofluoric acid (G3); and sandblasted with aluminum oxide (G4). All experimental samples were treated with silane and bonded with a primer and standardized amount of adhesive. After composite removal, each group was divided into subgroups randomly (n = 4), according to the porcelain polishing system used: Edenta (P1); Identoflex (P2); and Komet (P3). All 52 sample-surfaces were evaluated quantitatively with a profilometer, and a mean roughness profile (Ra) value was determined for each sample. Both control and experimental specimens were evaluated qualitatively using a scanning electron microscope (SEM) to assess surface morphology.
Results: Statistical analysis with analysis of variance (ANOVA) and post-hoc Tukey multiple comparisons test showed statistical differences between surface preparation groups (G1 ≠ G2 = G3 = G4), at α = .05 level of significance; as for polishing protocols, no statistical difference was found.
Conclusions: The surface preparation was the determinant for final surface texture. No combination between surface preparation and polishing system was able to reestablish the original glazed porcelain smoothness.
Transverse Dentoskeletal Features of Anterior Open Bite in the Mixed Dentition
Authors: Ballanti Fabiana , Franchi Lorenzo , Cozza Paola 
Published: February 2009

Abstract
Objective: To apply both conventional cephalometric analysis and morphometric analysis (thin-plate spline analysis) to posteroanterior (PA) cephalograms to test the hypothesis that the dentoskeletal features of subjects with anterior open bite in the mixed dentition are no different from those of normal controls.
Materials and Methods: A group of 22 white subjects (6 males, 16 females; mean age, 8.7 ± 0.7 years) with anterior open bite (AOBG) was compared with a control group (CG) of 22 white subjects (11 males, 11 females; mean age, 9.2 ± 0.8 years) with Class I occlusal relationships, and without anterior open bite and sucking habits. Subjects of both groups were in the mixed dentition and had no history of orthodontic treatment. Between-group statistical comparisons were performed with independent sample t-tests and permutation tests.
Results: AOBG exhibited statistically significant shape differences with respect to CG that consisted of a transverse contraction of the zygomatic region, of the maxilla (at both skeletal and dentoalveolar levels), and of the mandible (in both condylar and gonial regions), with a downward dislocation of point menton. With conventional cephalometrics, AOBG showed a statistically significant transverse deficiency in the zygomatic region (−4.8 mm), in the maxilla at both skeletal and dentoalveolar levels (−2.0 mm and −3.0 mm, respectively), and in the mandible in both condylar and gonial regions (−3.6 mm and −4.0 mm, respectively).
Conclusion: Subjects with anterior open bite showed transverse deficiencies in the zygomatic region, in the maxilla, and in the mandible when compared with normal subjects.
Skeletal Anomalies and Normal Variants in Patients with Palatally Displaced Canines
Authors: Leonardi Rosalia , Barbato Ersilia , Vichi Maurizio , Caltabiano Mario 
Published: February 2009

Abstract
Objective: To test the null hypothesis that there is no increased prevalence of skeletal anomalies and/or normal variants as evidenced by the cephalometric radiographs of patients with palatally displaced canines (PDC).
Materials and Methods: The treatment records of 38 white subjects between 14 and 20 years old with PDC were collected and evaluated retrospectively. Inclusion criteria for the study required that the case records include good-quality panoramic radiographs and lateral cephalometric radiographs with the first four cervical vertebrae clearly visible. The anomalies recorded for each case included sella bridge, atlanto-occipital ligament calcification or ponticulus posticus, and posterior arch atlas deficiency. A control group consisted of 70 consecutively treated subjects who had no other dental anomalies and whose maxillary canines had erupted normally. Fisher's exact test and Pearson's chi-square test were used to determine possible statistically significant differences in the incidence of skeletal anomalies and/or normal variants between the group of patients with PDC and the control group.
Results: The prevalence of skull anomalies and normal variants seen in cephalometric radiographs was increased in patients with PDC. Because of the presence of ponticulus posticus (Pearson's chi-square, P &lt; .050; Fisher's exact test, P &lt; .052), sella bridge (Pearson's chi-square, P &lt; .042; Fisher's exact test, P &lt; .042), and posterior arch deficiency (Pearson's chi-square, P &lt; .047; Fisher's exact test, P &lt; .039), statistically significant differences were observed between subjects with PDC and the control group.
Conclusions: The null hypothesis was rejected. There is an increased prevalence of skull skeletal anomalies and/or normal variants in patients with PDC.
Excessive production of sex hormones in a cat with an adrenocortical tumor
Authors: Millard Ralph P. , Pickens Erika H. , Wells Katherine L. 
Published: February 2009

Abstract
Case Description—A 13-year-old neutered male domestic shorthair cat was evaluated because it was spraying urine that had a strong odor and had developed aggressive behavior.
Clinical Findings—Physical examination did not detect any palpable testes within the scrotum; however, spines were detected on the penis. Abdominal ultrasonography revealed a mass in the region of the right adrenal gland. Results of adrenal hormonal analyses revealed considerable increases in serum concentrations of androstenedione and testosterone.
Treatment and Outcome—A mass associated with the right adrenal gland was found during exploratory laparotomy. There was no invasion of the mass into the caudal vena cava. No ectopic gonadal tissue was seen within the abdomen. Adrenalectomy of the right adrenal gland was performed, and histologic evaluation of the mass revealed an adrenocortical adenoma. Two weeks after surgery, serum concentrations of androgens had decreased. Eight weeks after surgery, the cat was no longer spraying urine and was acting affectionate toward the owner.
Clinical Relevance—Adrenal gland tumors can produce a variety of hormones other than cortisol. An adrenal gland tumor should be considered in neutered cats with newly developed physical and behavioral changes of a sexual nature. In the absence of debilitating conditions that are often associated with hyperadrenocorticism, cats undergoing adrenalectomy for an adrenal gland tumor that is producing sex hormones may have resolution of clinical signs and a good prognosis.
Synthesis of saccharide precursors for preparation of potential inhibitors of glycosyltranferases
Authors: Hirsch Ján , Koóš Miroslav , Tvaroška Igor 
Published: February 2009

AbstractEthyl 6-O-tert-butyldimethylsilyl-3,4-di-O-acetyl-2-thio-α-D-fructofuranoside (Va), its β-analog (Vb); as well as benzyl 6-O-tert-butyldimethylsilyl-3,4-di-O-acetyl-2-thio-α-D-fructofuranoside (Xa) and its β-analog (Xb), having an unprotected OH group at C-1, were prepared by sequential synthesis starting from commercially available D-fructose. These compounds represent suitable nucleophiles for the preparation of model carbohydrate mimetics of a glycosyltransferase inhibitor type in transition state. The structures of all compounds were confirmed by NMR spectral data and elemental analyses.
Comment améliorer l'accès au financement pour les PME d'Afrique subsaharienne ?
Authors: Lefilleur Julien 
Published: February 2009

Résumé L’accès au financement représente la principale contrainte rencontrée par les PME d’Afrique subsaharienne. Trois raisons poussent les acteurs du financement à éviter ces contreparties : un coût du risque surévalué, des coûts de transaction élevés et une insuffisante sécurisation des crédits. Le développement du financement des PME semble en grande partie dépendre de la capacité des acteurs privés à développer des systèmes financiers plus adaptés. L’application des principes de la micro finance au financement des PME est certainement une voie porteuse de potentiel. De même, le développement de produits de crédit permettant aux prêteurs d’être mieux sécurisés, ainsi que la multiplication des fonds de garantie auraient également un impact très positif sur le financement des PME.
L'éternel féminin est-il bien mort ?
Authors: Maisonneuve Jean 
Published: February 2009

« L’éternel féminin » n’est-il aujourd’hui qu’un stéréotype contesté, voire totalement périmé, ou garde-t-il encore une portée réelle et/ou imaginaire ? Peut-on articuler ses connotations ambivalentes et fluctuantes au cours des temps ? Que penser des critiques du féminisme et de certains mouvements extrêmes niant tout destin propre au genre et au sexe ? L’expression elle-même reste-t-elle compatible avec l’émancipation féminine ? Ces questions sont explorées à partir des positions divergentes de penseurs, contemporains ou non, et aussi de quelques observations et enquêtes significatives. L’auteur donne finalement son avis.
Du clivage au déni : l'école du neutre
Authors: Diet Emmanuel 
Published: February 2009

Dans le contexte contemporain, l’École, devenue anomique, ne s’attache plus à transmettre les modèles culturels étayant l’identification post-œdipienne au genre : avec la mise en crise de la famille et des modèles traditionnels, on assiste, dans l’espace pédagogique, à l’affrontement conflictuel et complexe des incorporats culturels intériorisés dans la famille, à l’école et dans la consommation médiatique, que le recours pédagogique prétend éviter par le recours à l’opératoire. De fait, on assiste alors à un retour massif du dénié, réactivant, à l’exemple des médias, les formes les plus violentes de la domination masculine et de l’exclusion du féminin dans des modalités pulsionnelles archaïques, faute d’une élaboration possible de l’identification sexuelle en souffrance par et dans la médiation culturelle.
Accident, hasard et destin chez Freud
Authors: Kamieniak Jean-Pierre 
Published: February 2009

Résumé Si la notion d’accident n’appartient pas à l’appareillage freudien, ce dernier n’en vient pas moins bouleverser profondément la compréhension que le sujet s’en fait : en découvrant l’existence d’un déterminisme psychique inconscient associé à l’impérieux besoin de causalité qui anime tout sujet, c’est le statut même de l’accidentel qui se voit remanié, posant alors de manière nouvelle le problème de la causalité.
La formation des thérapeutes familiaux et le génogramme paysager : un outil de développement personnel et de supervision
Authors: Pluymaekers Jacques , Nève-Hanquet Chantal 
Published: February 2009

Résumé Cet article aborde deux points : La manière dont le génogramme paysager peut être un outil de développement personnel et de supervision dans la formation des thérapeutes familiaux ; en effet, il permet à ceux-ci de découvrir par l’expérience vécue dans leur milieu d’origine, l’importance des règles familiales dans leur propre famille et dans celles qu’ils suivent en thérapie. Les étudiants peuvent alors approcher les résonances qui les traversent dans leur travail professionnel. La méthodologie du génogramme paysager qui allie deux pratiques : le génogramme et le jeu psychodramatique.
La mise en valeur de l'autonomie du stagiaire au sein de l'interdépendance
Authors: Georgieva Jenia , Georgiev Roumen 
Published: February 2009

Résumé Comme on attend du stagiaire en formation à la thérapie familiale qu’il acquière la capacité d’aider le système familial à offrir un terrain pour l’autonomie et la croissance personnelle de ses membres, on mettra l’accent dans sa formation sur son vécu d’un processus d’autonomisation dans et à travers l’interdépendance. En plus d’être un point d’ancrage de son développement personnel et professionnel, un tel processus contrecarre les effets de déséquilibre du contexte plus large, qui ont tendance à se reproduire au sein du groupe de formation. Son importance croît lorsque la formation a lieu dans un contexte social qui a abruptement fluctué d’une orientation excessivement groupale vers des valeurs fortement individualistes, comme dans les « sociétés en transition ». La sensibilité de l’équipe des formateurs à leurs propres déséquilibres et leurs tentatives de les surmonter modèleront et favoriseront le développement personnel des stagiaires par le biais des échanges entre eux. Valoriser l’autonomie dans le cadre de méthodes et de techniques de formation qui traitent de l’interdépendance demande que celles-ci soient conçues en tenant compte des espaces et des frontières nécessaires aux individus, aux couples, aux sous-groupes et au groupe dans son ensemble, et qu’elles soient congruentes avec la suite des étapes par lesquelles un groupe qui se crée doit passer.
Des compétences thérapeutiques aux compétences de chercheur : le partage d'un terrain commun
Authors: Stratton Peter , Hanks Helga 
Published: February 2009

Résumé Cet article est basé sur un atelier donné lors d’un Congrès organisé par EFTA/TIC 4 à Rhodes en 2006. Son objectif est d’encourager les réflexions sur les différentes manières dont la formation peut favoriser une vue positive de la recherche. Nous allons décrire des aspects de la formation à la recherche à Leeds afin de montrer le capital apporté par les approches systémiques à l’apprentissage et au changement lorsqu’on s’appuie sur le « terrain commun » qui existe entre les compétences nécessaires pour la recherche et le développement d’aptitudes systémiques chez les stagiaires. Lors de la présentation de notre atelier à Rhodes, nous avons utilisé les approches auxquelles nous avons recours dans la formation donnée dans le Master en thérapie familiale systémique au Centre de Thérapie Familiale et de Recherche de Leeds. Les questions soulevées par les participants ont concerné les mêmes sujets que ceux que nous traitons au cours de la partie de la formation à la thérapie familiale consacrée à la recherche, et donc une description des aspects significatifs de notre formation répondra à certaines de ces préoccupations. Cet article présente donc des aspects de la formation tout en décrivant des idées supplémentaires apparues lors de la préparation de l’atelier et au cours de celui-ci.