7,071 research outputs found

    Noncommutative Particles in Curved Spaces

    Full text link
    We present a formulation in a curved background of noncommutative mechanics, where the object of noncommutativity θμν\theta^{\mu\nu} is considered as an independent quantity having a canonical conjugate momentum. We introduced a noncommutative first-order action in D=10 curved spacetime and the covariant equations of motions were computed. This model, invariant under diffeomorphism, generalizes recent relativistic results.Comment: 1+15 pages. Latex. New comments and results adde

    Evaporação e evapotranspiração.

    Get PDF
    Esta publicação tem por objetivo dar algumas informações básicas para aqueles que trabalham com irrigação, solucionarem seus problemas de estimativa de demanda d'água das culturas por via climatológica em função de sua disponibilidade de dados meteorológicos.bitstream/item/132952/1/34345-1.pd

    Hamiltonian embedding of the massive noncommutative U(1) theory

    Full text link
    We show that the massive noncommutative U(1) can be embedded in a gauge theory by using the BFFT Hamiltonian formalism. By virtue of the peculiar non-Abelian algebraic structure of the noncommutative massive U(1) theory, several specific identities involving Moyal commutators had to be used in order to make the embedding possible. This leads to an infinite number of steps in the iterative process of obtaining first-class constraints. We also shown that the involutive Hamiltonian can be constructed.Comment: 8 pages, Revtex (multicol

    Patterns of childhood adversity and health outcomes in early adolescence: Results from the Generation XXI cohort

    Get PDF
    This longitudinal population-based birth cohort study aims to identify childhood adversity patterns over the first 13 years of life and to examine its association with health-related behaviours and outcomes in early adolescence. Using data from the Portuguese birth cohort Generation XXI, we performed latent class analysis to explore the underlying patterns of adversity from birth to early adolescence, using 13 adversity items assessed in five time points. Health-related behaviours and outcomes were evaluated at 13 years. Adjusting for parental unemployment, logistic regression models were performed to determine the association between adversity patterns and outcomes. Among 8647 participants, three adversity patterns were identified: low adversity (56.1%), household dysfunction (17.2%) and multiple adversities (26.7%). For the household dysfunction pattern, girls and boys showed associations with increased odds of alcohol/tobacco use (adjusted odds ratio [AOR]: 1.78; 95% confidence interval [CI]: 1.32-2.40; AOR:1.84; CI:1.38-2.46, respectively) and depressive symptoms (AOR:2.34; CI:1.58-3.48; AOR:5.45; CI:2.86-10.38, respectively). Boys also presented low consumption of fruits/vegetables (AOR:1.51; CI:1.04-2.19). For the multiple adversities pattern, both girls and boys showed an increased probability of alcohol/tobacco use (AOR:1.82; CI:1.42-2.33; AOR:1.63; CI:1.30-2.05, respectively) and depressive symptoms (AOR:3.41; CI:2.46-4.72; AOR:5.21; CI:2.91-9.32, respectively). Boys also revealed increased odds of low consumption of fruits/vegetables (AOR:1.67; CI:1.24-2.23). Childhood adversity patterns are associated with unhealthy behaviours and depressive symptoms in early adolescence. Public policies and early interventions targeting vulnerable children, families and communities can potentially reduce the detrimental effects of adversities on health and promote individual and community resilience.This work was supported by the European Regional Development Fund (ERDF) through the Operational Programme Competitiveness and Internationalisation and national fundingfrom the Foundation for Science and Technology (FCT), Portuguese Ministry of Science, Technology and Higher Education [POCI-01-0145-FEDER-029567; PTDC/SAU-PUB/29567/2017; 2022.06837.PTDC; UIDB/04750/2020; LA/P/0064/2020; CEECIND/01516/2017; SFRH/BD/144503/2019]; Administracao Regional de Saude Norte (Regional Department of Ministry of Health); Fundacao Calouste Gulbenkian

    Characterization of a rare analphoid supernumerary marker chromosome in mosaic

    Get PDF
    Abstract publicado em: Chromosome Research. 2015;23(Suppl 1):67-8. doi:10.1007/s10577-015-9476-6Analphoid supernumerary marker chromosomes (SMCs) are a rare subclass of SMCs C-band-negative and devoid of alpha-satellite DNA. These marker chromosomes cannot be identified unambiguously by conventional banding techniques alone being necessary to apply molecular cytogenetic methods in favour of a detailed characterization. In this work we report an analphoid SMC involving the terminal long arm of chromosome 7, in 9 years-old boy with several dysmorphic features and severe development delay. Cytogenetic analysis revealed a mosaic karyotype with the presence of an extra SMC, de novo, in 20 % of lymphocytes and 73 % of fibroblast cells. FISH analysis with alpha-satellite probes for all chromosomes, whole chromosome painting probe for chromosome 7, and D7S427 and TelVysion 7q probes, allowed establishing the origin of the SMC as an analphoidmarker resulting of an invdup rearrangement of 7q36-qter region. Affimetrix CytoScan HD microarray analysis, redefined the SMC to arr[hg19] 7q35(143696249-159119707)×2~3, which correspond to a gain of 15.42 Mb and encloses 67 OMIM genes, 16 of which are associated to disease. This result, combined with detailed clinical description, will provide an important means for better genotype-phenotype correlation and a more suitable genetic counselling to the patient and his parents, despite the additional difficulty resulting from being a mosaic (expression varies in different tissues). Analphoid SMCs derived from chromosome 7 are very rare, with only three cases reported so far. With this case we hope contribute to a better understanding of this type of chromosome rearrangements which are difficult for genetic counselling

    Clustering stability and ground truth: numerical experiments

    Get PDF
    Stability has been considered an important property for evaluating clustering solutions. Nevertheless, there are no conclusive studies on the relationship between this property and the capacity to recover clusters inherent to data (“ground truth”). This study focuses on this relationship, resorting to experiments on synthetic data generated under diverse scenarios (controlling relevant factors) and experiments on real data sets. Stability is evaluated using a weighted cross-validation procedure. Indices of agreement (corrected for agreement by chance) are used both to assess stability and external validity. The results obtained reveal a new perspective so far not mentioned in the literature. Despite the clear relationship between stability and external validity when a broad range of scenarios is considered, the within-scenarios conclusions deserve our special attention: faced with a specific clustering problem (as we do in practice), there is no significant relationship between clustering stability and the ability to recover data clustersinfo:eu-repo/semantics/publishedVersio

    Resultados preliminares do projeto zoneamento do déficit hídrico do TSA utilizando técnicas de teledetecção espacial.

    Get PDF
    Definição do problema; Apresentação do organograma de trabalho a ser realizado; Dados tratados; Constituição do arquivo bruto.bitstream/item/143278/1/ID-31857.pdfNão publicado
    corecore