933 resultados para non-trivial data structures


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In this paper, we investigate the agency costs of government ownership and their impact on corporate governance and firm value. China is used as a laboratory because of the prevalent state shareholdings in exchange-listed firms. In this context, we specifically consider the trade-offs involved in the voluntary formation of an audit committee when the controlling shareholder is the state. The decision to improve corporate governance (in this case, introduce an audit committee) is shown to be value relevant and a function of existing agency relationships and non-trivial implementation costs. Our findings are robust to the level of pyramid groups, the ownership-control wedge, and financial leverage. The research adds to the debate regarding the effect of government shareholdings on corporate culture and performance - a topic that hastaken on renewed importance in recent times.

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Attempts to inhibit the recognition of soluble antigens by T lymphocytes using antibodies specific for the antigen in question have been uniformally unsuccessful, in contrast to the observed specific inhibition of antibody generation by B cells. One exception is the unique situation whereby anti-hapten antisera inhibit the T-cell proliferative responses observed when hapten-specific T lymphocytes or clones are cultured with hapten-derivatized cells or proteins. The inability to inhibit T-cell functions by antigen-specific antibodies has been interpreted in several ways: (1) T cells possess a different repertoire from B cells; (2) the antibodies tested recognize epitopes present on the native antigen, whereas T cells recognize non-native (processed) structures; (3) the antigenic determinant(s) recognized by T cells on the surface of antigen presenting cells are either not accessible to antibodies, or are present in low amounts. The development of antigen-specific T-cell clones and monoclonal antibodies both specific for the same antigenic determinants now allows this question to be investigated definitively. Here, we report for the first time the specific inhibition of antigen-induced T-cell clone proliferation by a monoclonal antibody directed against the relevant soluble protein antigen.

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Somatic copy number aberrations (CNA) represent a mutation type encountered in the majority of cancer genomes. Here, we present the 2014 edition of arrayMap (http://www.arraymap.org), a publicly accessible collection of pre-processed oncogenomic array data sets and CNA profiles, representing a vast range of human malignancies. Since the initial release, we have enhanced this resource both in content and especially with regard to data mining support. The 2014 release of arrayMap contains more than 64,000 genomic array data sets, representing about 250 tumor diagnoses. Data sets included in arrayMap have been assembled from public repositories as well as additional resources, and integrated by applying custom processing pipelines. Online tools have been upgraded for a more flexible array data visualization, including options for processing user provided, non-public data sets. Data integration has been improved by mapping to multiple editions of the human reference genome, with the majority of the data now being available for the UCSC hg18 as well as GRCh37 versions. The large amount of tumor CNA data in arrayMap can be freely downloaded by users to promote data mining projects, and to explore special events such as chromothripsis-like genome patterns.

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This paper studies global webs on the projective plane with vanishing curvature. The study is based on an interplay of local and global arguments. The main local ingredient is a criterium for the regularity of the curvature at the neighborhood of a generic point of the discriminant. The main global ingredient, the Legendre transform, is an avatar of classical projective duality in the realm of differential equations. We show that the Legendre transform of what we call reduced convex foliations are webs with zero curvature, and we exhibit a countable infinity family of convex foliations which give rise to a family of webs with zero curvature not admitting non-trivial deformations with zero curvature.

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Most life science processes involve, at the atomic scale, recognition between two molecules. The prediction of such interactions at the molecular level, by so-called docking software, is a non-trivial task. Docking programs have a wide range of applications ranging from protein engineering to drug design. This article presents SwissDock, a web server dedicated to the docking of small molecules on target proteins. It is based on the EADock DSS engine, combined with setup scripts for curating common problems and for preparing both the target protein and the ligand input files. An efficient Ajax/HTML interface was designed and implemented so that scientists can easily submit dockings and retrieve the predicted complexes. For automated docking tasks, a programmatic SOAP interface has been set up and template programs can be downloaded in Perl, Python and PHP. The web site also provides an access to a database of manually curated complexes, based on the Ligand Protein Database. A wiki and a forum are available to the community to promote interactions between users. The SwissDock web site is available online at http://www.swissdock.ch. We believe it constitutes a step toward generalizing the use of docking tools beyond the traditional molecular modeling community.

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L'objectiu del projecte és la creació de les estructures de dades necessàries, així com els mètodes d'accés a aquestes dades. No contempla el disseny de la interfície d'usuari, ni el programari d'instal·lació del servidor ni client.

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En aquest treball s'amplia la implementació en Java de les estructures de dades iniciada per Esteve Mariné, utilitzant el seu disseny bàsic. Concretament, s'ha fet la programació de les estructures de a) classes disjuntes, utilitzant els algorismes de llistes encadenades i amb estructura d'arbre, b) monticles, amb els algorismes binari, binomial i de Fibonacci, i c) arbres de recerca basats en l'algorisme d'arbre binari vermell-negre, el qual complementa els dos ja existents amb algorismes d'encadenaments i AVL. Per a examinar l'evolució de les estructures, s'ha preparat un visualitzador gràfic interactiu amb l'usuari que permet fer les operacions bàsiques de l'estructura. Amb aquest entorn és possible desar les estructures, tornar a reproduir-les i desfer i tornar a repetir les operacions fetes sobre l'estructura. Finalment, aporta una metodologia, amb visualització mitjançant gràfics, de l'avaluació comparativa dels algorismes implementats, que permet modificar els paràmetres d'avaluació com ara nombre d'elements que s'han de tractar, algorismes que s'han de comparar i nombre de repeticions. Les dades obtingudes es poden exportar per a analitzar-les posteriorment.

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Starting with logratio biplots for compositional data, which are based on the principle of subcompositional coherence, and then adding weights, as in correspondence analysis, we rediscover Lewi's spectral map and many connections to analyses of two-way tables of non-negative data. Thanks to the weighting, the method also achieves the property of distributional equivalence

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This article analyzes Folner sequences of projections for bounded linear operators and their relationship to the class of finite operators introduced by Williams in the 70ies. We prove that each essentially hyponormal operator has a proper Folner sequence (i.e. a Folner sequence of projections strongly converging to 1). In particular, any quasinormal, any subnormal, any hyponormal and any essentially normal operator has a proper Folner sequence. Moreover, we show that an operator is finite if and only if it has a proper Folner sequence or if it has a non-trivial finite dimensional reducing subspace. We also analyze the structure of operators which have no Folner sequence and give examples of them. For this analysis we introduce the notion of strongly non-Folner operators, which are far from finite block reducible operators, in some uniform sense, and show that this class coincides with the class of non-finite operators.

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INTRODUCTION Due to their low CNS penetrance, there are concerns about the capacity of non-conventional PI-based ART (monotherapy and dual therapies) to preserve neurocognitive performance (NP). METHODS We evaluated the NP change of aviremic participants of the SALT clinical trial (1) switching therapy to dual therapy (DT: ATV/r+3TC) or triple therapy (TT: ATV/r+2NRTI) who agreed to perform an NP assessment (NPZ-5) at baseline and W48. Neurocognitive impairment and NP were assessed using AAN-2007 criteria (2) and global deficit scores (GDS) (3). Neurocognitive change (GDS change: W48 - baseline) and the effect of DT on NP evolution crude and adjusted by significant confounders were determined using ANCOVA. RESULTS A total of 158 patients were included (Table 1). They had shorter times because HIV diagnosis, ART initiation and HIV-suppression and their virologic outcome at W48 by snapshot was higher (79.1% vs 72.7%; p=0.04) compared to the 128 patients not included in the sub-study. By AAN-2007 criteria, 51 patients in each ART group (68% vs 63%) were neurocognitively impaired at baseline (p=0.61). Forty-seven patients were not reassessed at W48: 30 lost of follow-up (16 DT-14 TT) and 17 had non-evaluable data (6 DT-11 TT). Patients retested were more likely to be men (78.9% vs 61.4%) and had neurological cofounders (9.6% vs 0%) than patients non-retested. At W48, 3 out of 16 (5.7%) patients on DT and 6 out of 21 (10.5%) on TT who were non-impaired at baseline became impaired (p=0.49) while 10 out of 37 (18.9%) on DT and 7 out of 36 (12.3%) on TT who were neurocognitively impaired at baseline became non-impaired (p=0.44). Mean GDS changes (95% CI) were: Overall -0.2 (-0.3 to -0.04): DT -0.26 (-0.4 to -0.07) and TT -0.08 (-0.2 to 0.07). NP was similar between DT and TT (0.15). This absence of differences was also observed in all cognitive tests. Effect of DT: -0.16 [-0.38 to 0.06]) (r(2)=0.16) on NP evolution was similar to TT (reference), even after adjusting (DT: -0.11 [-0.33 to 0.1], TT: reference) by significant confounders (geographical origin, previous ATV use and CD4 cell count) (r(2)=0.25). CONCLUSIONS NP stability was observed after 48 weeks of follow up in the majority of patients whether DT or TT was used to maintain HIV-suppression. Incidence rates of NP impairment or NP impairment recovery were also similar between DT and TT.

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Globalization involves several facility location problems that need to be handled at large scale. Location Allocation (LA) is a combinatorial problem in which the distance among points in the data space matter. Precisely, taking advantage of the distance property of the domain we exploit the capability of clustering techniques to partition the data space in order to convert an initial large LA problem into several simpler LA problems. Particularly, our motivation problem involves a huge geographical area that can be partitioned under overall conditions. We present different types of clustering techniques and then we perform a cluster analysis over our dataset in order to partition it. After that, we solve the LA problem applying simulated annealing algorithm to the clustered and non-clustered data in order to work out how profitable is the clustering and which of the presented methods is the most suitable

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Most leadership and management researchers ignore one key design and estimation problem rendering parameter estimates uninterpretable: Endogeneity. We discuss the problem of endogeneity in depth and explain conditions that engender it using examples grounded in the leadership literature. We show how consistent causal estimates can be derived from the randomized experiment, where endogeneity is eliminated by experimental design. We then review the reasons why estimates may become biased (i.e., inconsistent) in non-experimental designs and present a number of useful remedies for examining causal relations with non-experimental data. We write in intuitive terms using nontechnical language to make this chapter accessible to a large audience.

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Background: Alternatively spliced exons play an important role in the diversification of gene function in most metazoans and are highly regulated by conserved motifs in exons and introns. Two contradicting properties have been associated to evolutionary conserved alternative exons: higher sequence conservation and higher rate of non-synonymous substitutions, relative to constitutive exons. In order to clarify this issue, we have performed an analysis of the evolution of alternative and constitutive exons, using a large set of protein coding exons conserved between human and mouse and taking into account the conservation of the transcript exonic structure. Further, we have also defined a measure of the variation of the arrangement of exonic splicing enhancers (ESE-conservation score) to study the evolution of splicing regulatory sequences. We have used this measure to correlate the changes in the arrangement of ESEs with the divergence of exon and intron sequences. Results: We find evidence for a relation between the lack of conservation of the exonic structure and the weakening of the sequence evolutionary constraints in alternative and constitutive exons. Exons in transcripts with non-conserved exonic structures have higher synonymous (dS) and non-synonymous (dN) substitution rates than exons in conserved structures. Moreover, alternative exons in transcripts with non-conserved exonic structure are the least constrained in sequence evolution, and at high EST-inclusion levels they are found to be very similar to constitutive exons, whereas alternative exons in transcripts with conserved exonic structure have a dS significantly lower than average at all EST-inclusion levels. We also find higher conservation in the arrangement of ESEs in constitutive exons compared to alternative ones. Additionally, the sequence conservation at flanking introns remains constant for constitutive exons at all ESE-conservation values, but increases for alternative exons at high ESE-conservation values. Conclusion: We conclude that most of the differences in dN observed between alternative and constitutive exons can be explained by the conservation of the transcript exonic structure. Low dS values are more characteristic of alternative exons with conserved exonic structure, but not of those with non-conserved exonic structure. Additionally, constitutive exons are characterized by a higher conservation in the arrangement of ESEs, and alternative exons with an ESE-conservation similar to that of constitutive exons are characterized by a conservation of the flanking intron sequences higher than average, indicating the presence of more intronic regulatory signals.

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Recent studies of American politics evidence that political polarization of both the electorate and the political elite have moved 'almost in tandem for the past half century' (McCarty et al., 2003, p.2), and that party polarization has steadily increased since the 1970s. On the other hand, the empirical literature on party platforms and implemented policies has consistently found an imperfect but nonnegligible correlation between electoral platforms and governmental policies: while platforms tend to be polarized, policies are moderate or centrist. However, existing theoretical models of political competition are not manifestly compatible with these observations. In this paper, we distinguish between electoral platforms and implemented policies by incorporating a non-trivial policy-setting process. It follows that voters may care not only about the implemented policy but also about the platform they support with their vote. We find that while parties tend to polarize their positions, the risk of alienating their constituency prevents them from radicalizing. The analysis evidences that the distribution of the electorate, and not only the (expected) location of a pivotal voter, matters in determining policies. Our results are consistent with the observation of polarized platforms and moderate policies, and the alienation and indifference components of abstention.

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This paper analyzes the relationship between ethnic fractionalization, polarization, and conflict. In recent years many authors have found empirical evidence that ethnic fractionalization has a negative effect on growth. One mechanism that can explain this nexus is the effect of ethnic heterogeneity on rent-seeking activities and the increase in potential conflict, which is negative for investment. However the empirical evidence supporting the effect of ethnic fractionalization on the incidence of civil conflicts is very weak. Although ethnic fractionalization may be important for growth, we argue that the channel is not through an increase in potential ethnic conflict. We discuss the appropriateness of indices of polarization to capture conflictive dimensions. We develop a new measure of ethnic heterogeneity that satisfies the basic properties associated with the concept of polarization. The empirical section shows that this index of ethnic polarization is a significant variable in the explanation of the incidence of civil wars. This result is robust to the presence of other indicators of ethnic heterogeneity, other sources of data for the construction of the index, and other data structures.