909 resultados para Hierarchical partition


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This paper describes a failure alert system and a methodology for content reuse in a new instructional design system called InterMediActor (IMA). IMA provides an environment for instructional content design, production and reuse, and for students’ evaluation based in content specification through a hierarchical structure of competences. The student assessment process and information extraction process for content reuse are explained.

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The populations of parasites and infectious agents are most of the time structured in complex hierarchy that lies beyond the classical nested design described by Wright's F-statistics (F(IS), F(ST) and F(IT)). In this note we propose a user-friendly step-by-step notice for using recent software (HierFstat) that computes and test fixation indices for any hierarchical structure. We add some tricks and tips for some special data kind (haploid, single locus), some other procedure (bootstrap over loci) and how to handle crossed factors.

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GeneID is a program to predict genes in anonymous genomic sequences designed with a hierarchical structure. In the first step, splice sites, and start and stop codons are predicted and scored along the sequence using position weight matrices (PWMs). In the second step, exons are built from the sites. Exons are scored as the sum of the scores of the defining sites, plus the log-likelihood ratio of a Markov model for coding DNA. In the last step, from the set of predicted exons, the gene structure is assembled, maximizing the sum of the scores of the assembled exons. In this paper we describe the obtention of PWMs for sites, and the Markov model of coding DNA in Drosophila melanogaster. We also compare other models of coding DNA with the Markov model. Finally, we present and discuss the results obtained when GeneID is used to predict genes in the Adh region. These results show that the accuracy of GeneID predictions compares currently with that of other existing tools but that GeneID is likely to be more efficient in terms of speed and memory usage.

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Reliable estimates of heavy-truck volumes are important in a number of transportation applications. Estimates of truck volumes are necessary for pavement design and pavement management. Truck volumes are important in traffic safety. The number of trucks on the road also influences roadway capacity and traffic operations. Additionally, heavy vehicles pollute at higher rates than passenger vehicles. Consequently, reliable estimates of heavy-truck vehicle miles traveled (VMT) are important in creating accurate inventories of on-road emissions. This research evaluated three different methods to calculate heavy-truck annual average daily traffic (AADT) which can subsequently be used to estimate vehicle miles traveled (VMT). Traffic data from continuous count stations provided by the Iowa DOT were used to estimate AADT for two different truck groups (single-unit and multi-unit) using the three methods. The first method developed monthly and daily expansion factors for each truck group. The second and third methods created general expansion factors for all vehicles. Accuracy of the three methods was compared using n-fold cross-validation. In n-fold cross-validation, data are split into n partitions, and data from the nth partition are used to validate the remaining data. A comparison of the accuracy of the three methods was made using the estimates of prediction error obtained from cross-validation. The prediction error was determined by averaging the squared error between the estimated AADT and the actual AADT. Overall, the prediction error was the lowest for the method that developed expansion factors separately for the different truck groups for both single- and multi-unit trucks. This indicates that use of expansion factors specific to heavy trucks results in better estimates of AADT, and, subsequently, VMT, than using aggregate expansion factors and applying a percentage of trucks. Monthly, daily, and weekly traffic patterns were also evaluated. Significant variation exists in the temporal and seasonal patterns of heavy trucks as compared to passenger vehicles. This suggests that the use of aggregate expansion factors fails to adequately describe truck travel patterns.

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BACKGROUND AND PURPOSE: We compared among young patients with ischemic stroke the distribution of vascular risk factors among sex, age groups, and 3 distinct geographic regions in Europe. METHODS: We included patients with first-ever ischemic stroke aged 15 to 49 years from existing hospital- or population-based prospective or consecutive young stroke registries involving 15 cities in 12 countries. Geographic regions were defined as northern (Finland, Norway), central (Austria, Belgium, France, Germany, Hungary, The Netherlands, Switzerland), and southern (Greece, Italy, Turkey) Europe. Hierarchical regression models were used for comparisons. RESULTS: In the study cohort (n=3944), the 3 most frequent risk factors were current smoking (48.7%), dyslipidemia (45.8%), and hypertension (35.9%). Compared with central (n=1868; median age, 43 years) and northern (n=1330; median age, 44 years) European patients, southern Europeans (n=746; median age, 41 years) were younger. No sex difference emerged between the regions, male:female ratio being 0.7 in those aged <34 years and reaching 1.7 in those aged 45 to 49 years. After accounting for confounders, no risk-factor differences emerged at the region level. Compared with females, males were older and they more frequently had dyslipidemia or coronary heart disease, or were smokers, irrespective of region. In both sexes, prevalence of family history of stroke, dyslipidemia, smoking, hypertension, diabetes mellitus, coronary heart disease, peripheral arterial disease, and atrial fibrillation positively correlated with age across all regions. CONCLUSIONS: Primary preventive strategies for ischemic stroke in young adults-having high rate of modifiable risk factors-should be targeted according to sex and age at continental level.

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Previous microarray studies on breast cancer identified multiple tumour classes, of which the most prominent, named luminal and basal, differ in expression of the oestrogen receptor alpha gene (ER). We report here the identification of a group of breast tumours with increased androgen signalling and a 'molecular apocrine' gene expression profile. Tumour samples from 49 patients with large operable or locally advanced breast cancers were tested on Affymetrix U133A gene expression microarrays. Principal components analysis and hierarchical clustering split the tumours into three groups: basal, luminal and a group we call molecular apocrine. All of the molecular apocrine tumours have strong apocrine features on histological examination (P=0.0002). The molecular apocrine group is androgen receptor (AR) positive and contains all of the ER-negative tumours outside the basal group. Kolmogorov-Smirnov testing indicates that oestrogen signalling is most active in the luminal group, and androgen signalling is most active in the molecular apocrine group. ERBB2 amplification is commoner in the molecular apocrine than the other groups. Genes that best split the three groups were identified by Wilcoxon test. Correlation of the average expression profile of these genes in our data with the expression profile of individual tumours in four published breast cancer studies suggest that molecular apocrine tumours represent 8-14% of tumours in these studies. Our data show that it is possible with microarray data to divide mammary tumour cells into three groups based on steroid receptor activity: luminal (ER+ AR+), basal (ER- AR-) and molecular apocrine (ER- AR+).

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Error-correcting codes and matroids have been widely used in the study of ordinary secret sharing schemes. In this paper, the connections between codes, matroids, and a special class of secret sharing schemes, namely, multiplicative linear secret sharing schemes (LSSSs), are studied. Such schemes are known to enable multiparty computation protocols secure against general (nonthreshold) adversaries.Two open problems related to the complexity of multiplicative LSSSs are considered in this paper. The first one deals with strongly multiplicative LSSSs. As opposed to the case of multiplicative LSSSs, it is not known whether there is an efficient method to transform an LSSS into a strongly multiplicative LSSS for the same access structure with a polynomial increase of the complexity. A property of strongly multiplicative LSSSs that could be useful in solving this problem is proved. Namely, using a suitable generalization of the well-known Berlekamp–Welch decoder, it is shown that all strongly multiplicative LSSSs enable efficient reconstruction of a shared secret in the presence of malicious faults. The second one is to characterize the access structures of ideal multiplicative LSSSs. Specifically, the considered open problem is to determine whether all self-dual vector space access structures are in this situation. By the aforementioned connection, this in fact constitutes an open problem about matroid theory, since it can be restated in terms of representability of identically self-dual matroids by self-dual codes. A new concept is introduced, the flat-partition, that provides a useful classification of identically self-dual matroids. Uniform identically self-dual matroids, which are known to be representable by self-dual codes, form one of the classes. It is proved that this property also holds for the family of matroids that, in a natural way, is the next class in the above classification: the identically self-dual bipartite matroids.

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Automatic classification of makams from symbolic data is a rarely studied topic. In this paper, first a review of an n-gram based approach is presented using various representations of the symbolic data. While a high degree of precision can be obtained, confusion happens mainly for makams using (almost) the same scale and pitch hierarchy but differ in overall melodic progression, seyir. To further improve the system, first n-gram based classification is tested for various sections of the piece to take into account a feature of the seyir that melodic progression starts in a certain region of the scale. In a second test, a hierarchical classification structure is designed which uses n-grams and seyir features in different levels to further improve the system.

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The size of breeding units and the hierarchical population structure of the dioecious perennial herb Silene dioica were investigated on four closely situated island populations in the Skeppsvik Archipelago in northern Sweden. F-statistics analyses of nine polymorphic allozyme loci revealed that plants on single islands are divided into many small breeding units, between 0.2 m2 and 6 m2. Hierarchical analyses showed that levels of differentiation among subpopulations within islands (FPL=0.080) were about twice as high as among islands (FLT=0.048). These results are discussed in the light of what is known about pollen and seed movement in the archipelago.

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Cancer stem cells that display tumor-initiating properties have recently been identified in several distinct types of malignancies, holding promise for more effective therapeutic strategies. However, evidence of such cells in sarcomas, which include some of the most aggressive and therapy-resistant tumors, has not been shown to date. Here, we identify and characterize cancer stem cells in Ewing's sarcoma family tumors (ESFT), a highly aggressive pediatric malignancy believed to be of mesenchymal stem cell (MSC) origin. Using magnetic bead cell separation of primary ESFT, we have isolated a subpopulation of CD133+ tumor cells that display the capacity to initiate and sustain tumor growth through serial transplantation in nonobese diabetic/severe combined immunodeficiency mice, re-establishing at each in vivo passage the parental tumor phenotype and hierarchical cell organization. Consistent with the plasticity of MSCs, in vitro differentiation assays showed that the CD133+ cell population retained the ability to differentiate along adipogenic, osteogenic, and chondrogenic lineages. Quantitative real-time PCR analysis of genes implicated in stem cell maintenance revealed that CD133+ ESFT cells express significantly higher levels of OCT4 and NANOG than their CD133- counterparts. Taken together, our observations provide the first identification of ESFT cancer stem cells and demonstration of their MSC properties, a critical step towards a better biological understanding and rational therapeutic targeting of these tumors.

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The shape of alliance processes over the course of psychotherapy has already been studied in several process-outcome studies on very brief psychotherapy. The present study applies the shape-of-change methodology to short-term dynamic psychotherapies and complements this method with hierarchical linear modeling. A total of 50 psychotherapies of up to 40 sessions were included. Alliance was measured at the end of each session. The results indicate that a linear progression model is most adequate. Three main patterns were found: stable, linear, and quadratic growth. The linear growth pattern, along with the slope parameter, was related to treatment outcome. This study sheds additional light on alliance process research, underscores the importance of linear alliance progression for outcome, and also fosters a better understanding of its limitations.

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The aim of this article is to propose an anthropological point of view about informed consent in medicine. This quest for legitimacy should be read as a relational and social construction. In the heart of clinical complexity we find on one side various techniques employed by the medical community to validate research and to obtain the consent of patients. On the other side patients offer plural and subjective answers due to the doctor patient hierarchical and long relationship. Between constraints and freedoms, informed consent brings to light social relation.

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L'objet de la thèse est l'étude de l'endecasillabo dans l'oeuvre poétique de Giacomo Leopardi. D'un point de vue méthodologique, ce travail s'appuie sur la recherche de Marco Praloran et Arnaldo Soldani dédiée à l'endecasillabo de Pétrarque. L'auteur a comparé les Canti de Leopardi avec la production des plus grands écrivains de la fin du XIXème siècle et du début du XXème siècle Melchiorre Cesarotti (Poesie di Ossian), Giuseppe Parini (Il Mattino), Vittorio Alfieri (Le Rime e il Saul), Vincenzo Monti (l'ouvre poétique), Ugo Foscolo (Le Rime) et Alessandro Manzoni (l'oeuvre poétique). Nous avons là un répertoire de plusieurs milliers de vers qui ont été scandés non pas par l'intermédiaire d'un ordinateur, mais un à un en fonction de leur intonation. La première partie de la thèse est dédiée à l'analyse du rythme des différents auteurs, à des statistiques générales qui permettent de comparer ces données entre elles et avec les anciens auteurs italiens tels Dante, Pétrarque, Arioste, etc. De cette façon, nous pouvons avoir une vision globale de la prosodie italienne des origines jusqu'au XIXème siècle -vision qui permet de focaliser de manière exhaustive la technique de Leopardi. Dans la deuxième partie, l'auteur propose texte après texte la scansion de toute l'oeuvre poétique de Leopardi. Nous avons donc une lecture interprétative du rythíne de tous les poèmes qui tient compte de l'année de composition et les différentes typologies métriques des textes : par exemple, les canzoni, les idilli, les canti pisano-recanatesi. Dans cette deuxième partie, il faut souligner l'effort de lier la partition du rythme au contenu des différents textes.

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This article reviews the methodology of the studies on drug utilization with particular emphasis on primary care. Population based studies of drug inappropriateness can be done with microdata from Health Electronic Records and e-prescriptions. Multilevel models estimate the influence of factors affecting the appropriateness of drug prescription at different hierarchical levels: patient, doctor, health care organization and regulatory environment. Work by the GIUMAP suggest that patient characteristics are the most important factor in the appropriateness of prescriptions with significant effects at the general practicioner level.

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SUMMARY The human auditory cortex, located on the supratemporal plane of the temporal lobe, is divided in a primary auditory area and several non-primary areas surrounding it. These different areas show anatomical and functional differences. Many studies have focussed on auditory areas in non-human primates, using investigation techniques such as electrophysiological recordings, tracing of neural connections, or immunohistochemical and histochemical staining. Some of these studies have suggested parallel and hierarchical organization of the cortical auditory areas as well as subcortical auditory relays. In humans, only few studies have investigated these regions immunohistochemically, but activation and lesion studies speak in favour of parallel and hierarchical organization, very similar to that of non-human primates. Calcium-binding proteins and metabolic markers were used to investigate possible correlates of hierarchical and parallel organization in man. Calcium-binding proteins, parvalbumin, calretinin and calbindin, modulate the concentration of intracellular free calcium ions and were found in distinct subpopulations of GABAergic neurons in non-human primates species. In our study, their distribution showed several differences between auditory areas: the primary auditory area was darkly stained for both parvalbumin and calbindin, and their expression rapidly decreased while moving away from the primary area. This staining pattern suggests a hierarchical organization of the areas, in which the more darkly stained areas could correspond to an earlier integration level and the areas showing light staining may correspond to higher level integration areas. Parallel organization of primary and non-primary auditory areas was suggested by the complementarity, within a given area, between parvalbumin and calbindin expression across layers. To investigate the possible differences in the energetic metabolism of the cortical auditory areas, several metabolic markers were used: cytochrome oxidase and LDH1 were used as oxidative metabolism markers and LDH5 was used as glycolytic metabolism marker. The results obtained show a difference in the expression of enzymes involved in oxidative metabolism between areas. In the primary auditory area the oxidative metabolism markers were maximally expressed in layer IV. In contrast, higher order areas showed maximal staining in supragranular layers. The expression of LDH5 varied in patches, but did not differ between the different hierarchical auditory areas. The distribution of the two LDH enzymes isoforms also provides information about cellular aspects of metabolic organization, since neurons expressed the LDH1 isoform whereas astrocytes express primarily LDH5, but some astrocytes also contained the LDH1 isoform. This cellular distribution pattern supports the hypothesis of the existence of an astrocyte-neuron lactate shuttle, previously suggested in rodent studies, and in particular of lactate transfer from astrocytes, which produce lactate from the glucose obtained from the circulation, to neurons that use lactate as energy substrate. In conclusion, the hypothesis of parallel and hierarchical organization of the auditory areas can be supported by CaBPs, cytochrome oxidase and LDH1 distribution. Moreover, the two LDHs cellular distribution pattern support the hypothesis of an astrocyte-neuron lactate shuttle in human cortex.