920 resultados para conditional
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Aquest treball recull les necessitats per la reintegració que presenten els delinqüents sexuals a les presons catalanes i com es poden abordar aquestes mitjançant un model que ha donat bons resultats a altres països: Circles of Support and Accountability (CoSA a partir d'ara). L'objectiu és conèixer com funcionen els Cercles de Suport i Responsabilitat i quins són els requisits necessaris per adaptar aquest model als serveis penitenciaris de Catalunya. Amb aquesta finalitat s'ha fet una anàlisi quantitativa dels principals trets de la població penitenciària catalana, s'ha revisat la bibliografia sobre el model CoSA i s'ha fet observació de camp en la seva aplicació al Regne Unit. També s'ha comptat amb les opinions d'experts i professionals de Catalunya i s'han fet entrevistes a una petita mostra de delinqüents sexuals en règim de semillibertat. Tot i que a Catalunya hi ha programes a les presons per potenciar la rehabilitació dels delinqüents sexuals, la investigació destaca l’important paper del suport social i del manteniment dels canvis del tractament en el medi comunitari com elements clau per la reducció de la reincidència. El model Cercles optimitza l'efecte d'aquests processos i alhora ofereix un model de supervisió que concilia l'objectiu de protecció pública amb la reintegració del delinqüent. De l'estudi de la població penitenciària es conclou que hi ha una part d'interns que es podrien beneficiar d'aquest programa i que el reconeixen com una font important de suport davant les importants dificultats que troben en el procés de retorn a la llibertat. Es proposa un programa CerclesCat adaptat a la realitat del sistema penitenciari català i es descriu el procés d'implementació.
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Este trabajo recoge las necesidades para la reintegración que presentan los delincuentes sexuales de las prisiones catalanas y cómo se pueden abordar éstas mediante un modelo que ha dado buenos resultados en otros países: Circles of Support and Accountability (CoSA a partir de ahora). El objetivo es conocer cómo funcionan los Círculos de Apoyo y Responsabilidad y cuáles son los requisitos necesarios para adaptar este modelo a los servicios penitenciarios de Cataluña. Con este fin se ha hecho un análisis cuantitativo de los principales rasgos de la población penitenciaria catalana, se ha revisado la bibliografía sobre el modelo CoSA y se ha hecho observación de campo en su aplicación en el Reino Unido. También se ha contado con las opiniones de expertos y profesionales de Cataluña y se han realizado entrevistas a una pequeña muestra de delincuentes sexuales en régimen de semilibertad. Aunque en Cataluña hay programas en las prisiones para potenciar la rehabilitación de los delincuentes sexuales, la investigación destaca el importante papel del apoyo social y del mantenimiento de los cambios del tratamiento en el medio comunitario como elementos clave para la reducción de la reincidencia. El modelo de Círculos optimiza el efecto de estos procesos, y muestra un modelo de supervisión que concilia el objetivo de protección pública con la reintegración del delincuente. Del estudio de la población penitenciaria se concluye que hay una parte de internos que podrían beneficiarse de este programa y que lo reconocen como una fuente importante de apoyo ante las importantes dificultades que encuentran en el proceso de retorno a la libertad. Se propone un programa CerclesCat adaptado a la realidad del sistema penitenciario catalán y se describe el proceso de implementación.
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We consider the problem of estimating the mean hospital cost of stays of a class of patients (e.g., a diagnosis-related group) as a function of patient characteristics. The statistical analysis is complicated by the asymmetry of the cost distribution, the possibility of censoring on the cost variable, and the occurrence of outliers. These problems have often been treated separately in the literature, and a method offering a joint solution to all of them is still missing. Indirect procedures have been proposed, combining an estimate of the duration distribution with an estimate of the conditional cost for a given duration. We propose a parametric version of this approach, allowing for asymmetry and censoring in the cost distribution and providing a mean cost estimator that is robust in the presence of extreme values. In addition, the new method takes covariate information into account.
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SUMMARY Regulation of sodium excretion by the kidney is a key mechanism in the long term regulation of blood pressure, and when altered it constitutes a risk factor for the appearance of arterial hypertension. Aldosterone, which secretion depends upon salt intake in the diet, is a steroid hormone that regulates sodium reabsorption in the distal part of the nephron (functional unit of the kidney) by modulating gene transcription. It has been shown that it can act synergistically with the peptidic hormone insulin through the interaction of their signalisation pathways. Our work consisted of two distinct parts: 1) the in vitro and in vivo characterisation of Glucocorticoid-Induced Leucine Zipper (GILZ) (an aldosterone-induced gene) mechanism of action; 2) the in vitro characterisation of insulin mechanism of action and its interaction with aldosterone. GILZ mRNA, coded by the TSC22D3 gene, is strongly induced by aldosterone in the cell line of principal cells of the cortical collecting duct (CCD) mpkCCDc14, suggesting that GILZ is a mediator of aldosterone response. Co-expression of GILZ and the amiloride-sensitive epithelial sodium channel ENaC in vitro in the Xenopus oocyte expression system showed that GILZ has no direct effect on the ENaC-mediated Na+ current in basal conditions. To define the role of GILZ in the kidney and in other organs (colon, heart, skin, etc.), a conditional knock-out mouse is being produced and will allow the in vivo study of its role. Previous data showed that insulin induced a transepithelial sodium transport at supraphysiological concentrations. Insulin and the insulin-like growth factor 1 (IGF-1) are able to bind to each other receptor with an affinity 50 to 100 times lower than to their cognate receptor. Our starting hypothesis was that the insulin effect observed at these supraphysiological concentrations is actually mediated by the IGF receptor type 1 (IGF-1R). In a new cell line that presents all the characteristics of the principal cells of the CCD (mCCDc11) we have shown that both insulin and IGF-1 induce a physiologically significant increase of Na+ transport through the activation of IGF-1R. Aldosterone and insulin/IGF-1 have an additive effect on Na+ transport, through the activation of the PI3-kinase (PI3-K) pathway and the phosphorylation of the serum- and glucocorticoid-induced kinase 1 (Sgk1) by the IGF-1R, and the induction of Sgk1 expression by aldosterone. Thus, Sgk1 integrates IGF-1/insulin and aldosterone effects. We suggest that IGF-1 is physiologically relevant in the modulation of sodium balance, while insulin can only regulate Na+ transport at supraphysiological conditions. Both hormones would bind to the IGF-1R and induce Na+ transport by activating the PI3-K PDK1/2 - Sgk1 pathway. We have shown for the first time that Sgk1 is expressed and phosphorylated in principal cells of the CCD in basal conditions, although the mechanism that maintains Sgk1 phosphorylation is not known. This new role for IGF-1 suggests that it could be a salt susceptibility gene. In effect, IGF-1 stimulates Na+ and water transport in the kidney in vivo. Moreover, 35 % of the acromegalic patients (overproduction of growth hormone and IGF-1) are hypertensives (higher proportion than in normal population), and genetic analysis suggest a link between the IGF-1 gene locus and blood pressure. RÉSUMÉ La régulation de l'excrétion rénale de sodium (Na+) joue un rôle principal dans le contrôle à long terme de la pression sanguine, et ses altérations constituent un facteur de risque de l'apparition d'une hypertension artérielle. L'aldosterone, dont la sécrétion dépend de l'apport en sel dans la diète, est une hormone stéroïdienne qui régule la réabsorption de Na+ dans la partie distale du nephron (unité fonctionnelle du rein) en contrôlant la transcription de gènes. Elle peut agir de façon synergistique avec l'hormone peptidique insuline, probablement via l'interaction de leurs voies de signalisation cellulaire. Le but de notre travail comportait deux volets: 1) caractériser in vitro et in vivo le mécanisme d'action du Glucocorticoid Induced Leucine Zipper (GILZ) (un gène induit par l'aldosterone); 2) caractériser in vitro le mécanisme d'action de l'insuline et son interaction avec l'aldosterone. L'ARNm de GILZ, codé par le gène TSC22D3, est induit par l'aldosterone dans la lignée cellulaire de cellules principales du tubule collecteur cortical (CCD) mpkCCDc14, suggérant que GILZ est un médiateur potentiel de la réponse à l'aldosterone. La co-expression in vitro de GILZ et du canal à Na+ sensible à l'amiloride ENaC dans le système d'expression de l'oocyte de Xénope a montré que GILZ n'a pas d'effet sur les courants sodiques véhiculées par ENaC en conditions basales. Une souris knock-out conditionnelle de GILZ est en train d'être produite et permettra l'étude in vivo de son rôle dans le rein et d'autres organes. Des expériences préliminaires ont montré que l'insuline induit un transport transépithelial de Na+ à des concentrations supraphysiologiques. L'insuline et l'insulin-like growth factor 1 (IGF-1) peuvent se lier à leurs récepteurs réciproques avec une affinité 50 à 100 fois moindre qu'à leur propre récepteur. Nous avons donc proposé que l'effet de l'insuline soit médié par le récepteur à l'IGF type 1 (IGF-1R). Dans une nouvelle lignée cellulaire qui présente toutes les caractéristiques des cellules principales du CCD (mCCDc11) nous avons montré que les deux hormones induisent une augmentation physiologiquement significative du transport du Na+ par l'activation des IGF-1 R. Aldosterone et insuline/IGF-1 ont un effet additif sur le transport de Na+, via l'activation de la voie de la PI3-kinase et la phosphorylation de la serum- and glucocorticoid-induced kinase 1 (Sgk1) par l'IGF-1R, dont l'expression est induite par l'aldosterone. Sgk1 intègre les effets de l'insuline et l'aldosterone. Nous proposons que l'IGF-1 joue un rôle dans la modulation physiologique de la balance sodique, tandis que l'insuline régule le transport de Na+ à des concentrations supraphysiologiques. Les deux hormones agissent en se liant à l'IGF-1R et induisent le transport de Na+ en activant la cascade de signalisation PI3-K - PDK1/2 - Sgk1. Nous avons montré pour la première fois que Sgk1 est exprimée et phosphorylée dans des conditions basales dans les cellules principales du CCD, mais le mécanisme qui maintient sa phosphorylation n'est pas connu. Ce nouveau rôle pour l'IGF-1 suggère qu'il pourrait être un gène impliqué de susceptibilité au sel. Aussi, l'IGF-1 stimule le transport rénal de Na+ in vivo. De plus, 35 % des patients atteints d'acromégalie (surproduction d'hormone de croissance et d'IGF-1) sont hypertensifs (prévalence plus élevée que la population normale), et des analyses génétiques suggèrent un lien entre le locus du gène de l'IGF-1 et la pression sanguine. RÉSUMÉ GRAND PUBLIC Nos ancêtres se sont génétiquement adaptés pendant des centaines de millénaires à un environnement pauvre en sel (chlorure de sodium) dans la savane équatoriale, où ils consommaient moins de 0,1 gramme de sel par jour. On a commencé à ajouter du sel aux aliments avec l'apparition de l'agriculture (il y a 5000 à 10000 années), et aujourd'hui une diète omnivore, qui inclut des plats préparés, contient plusieurs fois la quantité de sodium nécessaire pour notre fonction physiologique normale (environ 10 grammes par jour). Le corps garde sa concentration constante dans le sang en s'adaptant à une consommation très variable de sel. Pour ceci, il module son excrétion soit directement, soit en sécrétant des hormones régulatrices. Le rein joue un rôle principal dans cette régulation puisque l'excrétion urinaire de sel change selon la diète et peut aller d'une quantité dérisoire à plus de 36 grammes par jour. L'attention qu'on prête au sel est liée à sa relation avec l'hypertension essentielle. Ainsi, le contrôle rénal de l'excrétion de sodium et d'eau est le principal mécanisme dans la régulation de la pression sanguine, et une ingestion excessive de sel pourrait être l'un des facteurs-clé déclenchant l'apparition d'un phénotype hypertensif. L'hormone aldosterone diminue l'excrétion de sodium par le rein en modulant l'expression de gènes qui pourraient être impliqués dans la sensibilité au sel. Dans une lignée cellulaire de rein l'expression du gène TSC22D3, qui se traduit en la protéine Glucocorticoid Induced Leucine Zipper (GILZ), est fortement induite par l'aldosterone. Ceci suggère que GILZ est un médiateur potentiel de l'effet de l'aldosterone, et pourrait être impliqué dans la sensibilité au sel. Pour analyser la fonction de GILZ dans le rein plusieurs approches ont été utilisées. Par exemple, une souris dans laquelle GILZ est spécifiquement inactivé dans le rein est en train d'être produite et permettra l'étude du rôle de GILZ dans l'organisme. De plus, on a montré que GILZ, en conditions basales, n'a pas d'effet direct sur la protéine transportant le sodium à travers la membrane des cellules, le canal sodique épithélial ENaC. On a aussi essayé de trouver des protéines qui interagissent directement avec GILZ utilisant une technique appelée du « double-hybride dans la levure », mais aucun candidat n'a émergé. Des études ont montré que, à de hautes concentrations, l'insuline peut aussi diminuer l'excrétion de sodium. A ces concentrations, elle peut activer son récepteur spécifique, mais aussi le récepteur d'une autre hormone, l'Insulin-Like Growth Factor 1 (IGF-1). En plus, l'infusion d'IGF-1 augmente la rétention rénale de sodium et d'eau, et des mutations du gène codant pour l'IGF-1 sont liées aux différents niveaux de pression sanguine. On a utilisé une nouvelle lignée cellulaire de rein développée dans notre laboratoire, appelée mCCDc11, pour analyser l'importance relative des deux hormones dans l'induction du transport de sodium. On a montré que les deux hormones induisent une augmentation significative du transport de sodium par l'activation de récepteurs à l'IGF-1 et non du récepteur à l'insuline. On a montré qu'à l'intérieur de la cellule leur activation induit une augmentation du transport sodique par le biais du canal ENaC en modifiant la quantité de phosphates fixés sur la protéine Serumand Glucocorticoid-induced Kinase 1 (Sgk1). On a finalement montré que l'IGF-1 et l'aldosterone ont un effet additif sur le transport de sodium en agissant toutes les deux sur Sgk1, qui intègre leurs effets dans le contrôle du transport de sodium dans le rein.
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Abstract¦This thesis examines through three essays the role of the social context and of people concern for justice in explaining workplace aggressive behaviors.¦In the first essay, I argue that a work group instrumental climate - a climate emphasizing respect of organizational procedures -deters employees to manifest counterproductive work behaviors through informal sanctions (i.e., socio-emotional disapproval) they anticipate from it for misbehaving. A contrario, a work group affective climate - a climate concerned about others' well-being - leads employees to infer less informal sanctions and thus indirectly facilitates counterproductive work behaviors. I additionally expect these indirect effects to be conditional on employees' level of conscientiousness and agreeableness. Cross-level structural equations on cross-sectional data obtained from 158 employees in 26 work groups supported my expectations. By promoting collective responsibility for the respect of organizational rules and by knowing what their work group considers threatening their well-being, leaders may be able to prevent counterproductive work behaviors.¦Adopting an organizational justice perspective, the second essay provides a theoretical explanation of why and how collective deviance can emerge in a collective. In interdependent situations, employees use justice perceptions to infer others' cooperative intent. Even if moral transgressions (e.g., injustice) are ambiguous, their repetition and configuration within a team can lead employees to assign blame and develop collective cynicism toward the transgressor. Over time, collective cynicism - a shared belief about the transgressor's intentional lack of integrity - progressively constrains the diversity of employees' response to blame and leads collective deviance to emerge. This essay contributes to workplace deviance research by offering a theoretical framework for investigations of the phenomenon at the collective level. It organizations effort to manage and prevent deviance should consider.¦In the third essay, I solve an apparent contradiction in the literature showing that justice concerns sometimes lead employees to react aggressively to injustice and sometimes to refrain from it. Drawing from just-world theory, a cross-sectional field study and an experiment provide evidence that retaliatory tendencies following injustice are moderated by personal and general just-world beliefs. Whereas a high personal just-world belief facilitates retaliatory reactions to injustice, a high general just-world belief attenuates such reactions. This essay uncovers a dark side of personal just-world belief and a bright one of general just-world belief, and participates to extend just-world theory to the working context.
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Myc family members play crucial roles in regulating cell proliferation, size, and differentiation during organogenesis. Both N-myc and c-myc are expressed throughout inner ear development. To address their function in the mouse inner ear, we generated mice with conditional deletions in either N-myc or c-myc. Loss of c-myc in the inner ear causes no apparent defects, whereas inactivation of N-myc results in reduced growth caused by a lack of proliferation. Reciprocally, the misexpression of N-myc in the inner ear increases proliferation. Morphogenesis of the inner ear in N-myc mouse mutants is severely disturbed, including loss of the lateral canal, fusion of the cochlea with the sacculus and utriculus, and stunted outgrowth of the cochlea. Mutant cochleas are characterized by an increased number of cells exiting the cell cycle that express the cyclin-dependent kinase inhibitor p27Kip1 and lack cyclin D1, both of which control the postmitotic state of hair cells. Analysis of different molecular markers in N-myc mutant ears reveals the development of a rudimentary organ of Corti containing hair cells and the underlying supporting cells. Differentiated cells, however, fail to form the highly ordered structure characteristic for the organ of Corti but appear as rows or clusters with an excess number of hair cells. The Kölliker's organ, a transient structure neighboring the organ of Corti and a potential source of ectopic hair cells, is absent in the mutant ears. Collectively, our data suggest that N-myc regulates growth, morphogenesis, and pattern formation during the development of the inner ear.
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BACKGROUND: Sex steroid hormones have been proposed to play a role in the development of non-epithelial ovarian cancers (NEOC) but so far no direct epidemiological data are available.METHODS: A case-control study was nested within the Finnish Maternity Cohort, the world's largest bio-repository of serum specimens from pregnant women. Study subjects were selected among women who donated a blood sample during a singleton pregnancy that led to the birth of their last child preceding diagnosis of NEOC. Case subjects were 41 women with sex-cord stromal tumors (SCST) and 21 with germ cell tumors (GCT). Three controls, matching the index case for age, parity at the index pregnancy, and date at blood donation were selected (n=171). Odds ratios (OR) and 95% confidence intervals (CI) associated with concentrations of testosterone, androstenedione, 17-OH-progesterone, progesterone, estradiol and sex hormone binding globulin (SHBG) were estimated through conditional logistic regression.RESULTS: For SCST, doubling of testosterone, androstenedione and 17-OH-progesterone concentrations were associated with about 2-fold higher risk of SCST [ORs and 95% CI of 2.16 (1.25-3.74), 2.16 (1.20-3.87), and 2.62 (1.27-5.38), respectively]. These associations remained largely unchanged after excluding women within 2, 4 or 6 years lag-time between blood donation and cancer diagnosis. Sex steroid hormones concentrations were not related to maternal risk of GCT.CONCLUSIONS: This is the first prospective study providing initial evidence that elevated androgens play a role in the pathogenesis of SCST. Impact: Our study may note a particular need for larger confirmatory investigations on sex steroids and NEOC.
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Background: In longitudinal studies where subjects experience recurrent incidents over a period of time, such as respiratory infections, fever or diarrhea, statistical methods are required to take into account the within-subject correlation. Methods: For repeated events data with censored failure, the independent increment (AG), marginal (WLW) and conditional (PWP) models are three multiple failure models that generalize Cox"s proportional hazard model. In this paper, we revise the efficiency, accuracy and robustness of all three models under simulated scenarios with varying degrees of within-subject correlation, censoring levels, maximum number of possible recurrences and sample size. We also study the methods performance on a real dataset from a cohort study with bronchial obstruction. Results: We find substantial differences between methods and there is not an optimal method. AG and PWP seem to be preferable to WLW for low correlation levels but the situation reverts for high correlations. Conclusions: All methods are stable in front of censoring, worsen with increasing recurrence levels and share a bias problem which, among other consequences, makes asymptotic normal confidence intervals not fully reliable, although they are well developed theoretically.
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A conditional heat-sensitive mutation in the cdc14 gene of the fission yeast Schizosaccharomyces pombe results in failure to form a septum. Cells become highly elongated and multinucleate as growth and nuclear division continue in the absence of cell division. This article describes the cloning of the cdc14 gene and the identification of its product, a protein of 240 amino acids, p28cdc14. A null allele of the cdc14 gene shows that the gene is essential for septum formation and completion of the cell-division cycle. Overexpression of the gene product, p28cdc14, causes cell-cycle arrest in late G2 before mitosis. Cells leaking past the block activate p34cdc2 kinase and show condensed chromosomes, but the normal rearrangements of the microtubules and microfilaments that are associated with the transition from interphase to mitosis do not occur. Overexpression of p28cdc14 in mutants, in which the timing of mitosis is altered, suggests that these effects may be mediated upstream of the mitotic inhibitor wee1. These data are consistent with the idea that p28cdc14 may play a role in both the initiation of mitosis and septum formation and, by doing so, be part of the mechanism that coordinates these two cell-cycle events.
On the evolution of harming and recognition in finite panmictic and infinite structured populations.
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Natural selection may favor two very different types of social behaviors that have costs in vital rates (fecundity and/or survival) to the actor: helping behaviors, which increase the vital rates of recipients, and harming behaviors, which reduce the vital rates of recipients. Although social evolutionary theory has mainly dealt with helping behaviors, competition for limited resources creates ecological conditions in which an actor may benefit from expressing behaviors that reduce the vital rates of neighbors. This may occur if the reduction in vital rates decreases the intensity of competition experienced by the actor or that experienced by its offspring. Here, we explore the joint evolution of neutral recognition markers and marker-based costly conditional harming whereby actors express harming, conditional on actor and recipient bearing different conspicuous markers. We do so for two complementary demographic scenarios: finite panmictic and infinite structured populations. We find that marker-based conditional harming can evolve under a large range of recombination rates and group sizes under both finite panmictic and infinite structured populations. A direct comparison with results for the evolution of marker-based conditional helping reveals that, if everything else is equal, marker-based conditional harming is often more likely to evolve than marker-based conditional helping.
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OBJECTIVE: We assessed the association between birth weight, weight change, and current blood pressure (BP) across the entire age-span of childhood and adolescence in large school-based cohorts in the Seychelles, an island state in the African region. METHODS: Three cohorts were analyzed: 1004 children examined at age 5.5 and 9.1 years, 1886 children at 9.1 and 12.5, and 1575 children at 12.5 and 15.5, respectively. Birth and 1-year anthropometric data were gathered from medical files. The outcome was BP at age 5.5, 9.1, 12.5 or 15.5 years, respectively. Conditional linear regression analysis was used to estimate the relative contribution of changes in weight (expressed in z-score) during different age periods on BP. All analyses were adjusted for height. RESULTS: At all ages, current BP was strongly associated with current weight. Birth weight was not significantly associated with current BP. Upon adjustment for current weight, the association between birth weight and current BP tended to become negative. Conditional linear regression analyses indicated that changes in weight during successive age periods since birth contributed substantially to current BP at all ages. The strength of the association between weight change and current BP increased throughout successive age periods. CONCLUSION: Weight changes during any age period since birth have substantial impact on BP during childhood and adolescence, with BP being more responsive to recent than earlier weight changes.
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A simple chaotic flow is presented, which when driven by an identical copy of itself, for certain initial conditions, is able to display generalized synchronization instead of identical synchronization. Being that the drive and the response are observed in exactly the same coordinate system, generalized synchronization is demonstrated by means of the auxiliary system approach and by the conditional Lyapunov spectrum. This is interpreted in terms of changes in the structure of the system stationary points, caused by the coupling, which modify its global behavior.
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The cdc10 gene of the fission yeast S. pombe is required for traverse of the start control in late G1 and commitment to the mitotic cell cycle. To increase our understanding of the events which occur at start, a pseudoreversion analysis was undertaken to identify genes whose products may interact with cdc10 or bypass the requirement for it. A single gene, sct1+ (suppressor of cdc ten), has been identified, mutation of which suppresses all conditional alleles and a null allele of cdc10. Bypass of the requirement for cdc10+ function by sct1-1 mutations leads to pleiotropic defects, including microtubule, microfilament and nuclear structural abnormalities. Our data suggest that sct1 encodes a protein that is dependent upon cdc10+ either for its normal function or expression, or is a component of a checkpoint that monitors execution of p85cdc10 function.
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The paper presents some contemporary approaches to spatial environmental data analysis. The main topics are concentrated on the decision-oriented problems of environmental spatial data mining and modeling: valorization and representativity of data with the help of exploratory data analysis, spatial predictions, probabilistic and risk mapping, development and application of conditional stochastic simulation models. The innovative part of the paper presents integrated/hybrid model-machine learning (ML) residuals sequential simulations-MLRSS. The models are based on multilayer perceptron and support vector regression ML algorithms used for modeling long-range spatial trends and sequential simulations of the residuals. NIL algorithms deliver non-linear solution for the spatial non-stationary problems, which are difficult for geostatistical approach. Geostatistical tools (variography) are used to characterize performance of ML algorithms, by analyzing quality and quantity of the spatially structured information extracted from data with ML algorithms. Sequential simulations provide efficient assessment of uncertainty and spatial variability. Case study from the Chernobyl fallouts illustrates the performance of the proposed model. It is shown that probability mapping, provided by the combination of ML data driven and geostatistical model based approaches, can be efficiently used in decision-making process. (C) 2003 Elsevier Ltd. All rights reserved.
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This paper presents a Bayesian approach to the design of transmit prefiltering matrices in closed-loop schemes robust to channel estimation errors. The algorithms are derived for a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system. Two different optimizationcriteria are analyzed: the minimization of the mean square error and the minimization of the bit error rate. In both cases, the transmitter design is based on the singular value decomposition (SVD) of the conditional mean of the channel response, given the channel estimate. The performance of the proposed algorithms is analyzed,and their relationship with existing algorithms is indicated. As withother previously proposed solutions, the minimum bit error rate algorithmconverges to the open-loop transmission scheme for very poor CSI estimates.