2,670 research outputs found

    Cabibbo-suppressed non-leptonic B- and D-decays involving tensor mesons

    Get PDF
    The Cabibbo-suppressed non-leptonic decays of B (and D) mesons to final states involving tensor mesons are computed using the non-relativistic quark model of Isgur-Scora-Grinstein-Wise with the factorization hypothesis. We find that some of these B decay modes, as B --> (K^*, D^*)D^*_2, can have branching ratios as large as 6 x 10^{-5} which seems to be at the reach of future B factories.Comment: Latex, 11 pages, to appear in Phys. Rev.

    La violencia doméstica como configuración del vínculo en una pareja

    Get PDF
    El presente trabajo investigativo/intervenido se realizó con el fin de comprender, ¿cómo emerge la violencia doméstica en la configuración del vínculo de la pareja a través de los operadores temporo-espaciales? Los actores debían llevar un mínimo de dos años, en los que se presentará violencia en el ámbito doméstico en la relación de pareja, y querer participar en la investigación/intervención. El proceso metodológico se desarrolló a partir de la metodología cualitativa de segundo orden, donde el observador es parte esencial del proceso, del mismo modo se empleó un estudio de caso y con la información recogida se consignó en matrices de análisis para su interpretación por medio de un análisis categorial. Durante el procedimiento de la investigación/intervención se efectuó una búsqueda bibliográfica de las categorías propuestas, se contactaron los participantes con los cuales se firmó consentimiento informado y se realizaron siete sesiones. Para fines del estudio se tomó una mirada sistémica y compleja, conociendo y comprendiendo la configuración de la pareja, a través de la definición de cada una de las categorias: vínculo, pareja y violencia doméstica. Como resultado de la investigación/intervención surgieron comprensiones de pareja y violencia doméstica desde un enfoque relacional, sistémico y complejo, desde la noción vincular de Ángela Hernández (2010) a través de los operadores temporo-espaciales mito, rito y episteme.This research / intervened work was done in order to understand how domestic violence emerges in shaping the relationship of the couple through the temporo-spatial operators ?. The actors had to wear a minimum of two years in which violence in the domestic sphere in the relationship will be presented, and want to participate in research / intervention. The methodology was developed from the qualitative methodology of second order, where the observer is an essential part of the process, just as a case study was used and the information collected was entered in matrix analysis for interpretation by categorial analysis. During the process of research / intervention a literature search of the proposed categories was made, which participants signed informed consent was seven sessions were held contacted. For purposes of the study systemic and complex view it was taken, knowing and understanding the configuration of the couple, through the definition of each of the categories: link, family and domestic violence. As a result of the research / intervention understandings they arose partner and domestic violence from a relational, systemic and complex approach from the notion link Angela Hernandez (2010) through the temporo-spatial operators myth, ritual and episteme.PsicólogoPregrad

    Unraveling UBC 274: a morphological, kinematical and chemical analysis of a disrupting open cluster

    Get PDF
    We do a morphological, kinematic and chemical analysis of the disrupting cluster UBC 274 (2.5 Gyr, d=1778d=1778 pc) to study its global properties. We use HDBSCAN to obtain a new membership list up to 50 pc from its centre and up to magnitude G=19G=19 using Gaia EDR3 data. We use high resolution and high signal-to-noise spectra to obtain atmospheric parameters of 6 giants and subgiants, and individual abundances of 18 chemical species. The cluster has a highly eccentric (0.93) component, tilted \sim10 deg with respect to the plane of the Galaxy, which is morphologically compatible with the result of a test-particle simulation of a disrupting cluster. Our abundance analysis shows that the cluster has a subsolar metallicity of [Fe/H]=0.08±0.02=-0.08\pm0.02. Its chemical pattern is compatible with that of Ruprecht 147, of similar age but located closer to the Sun, with the remarkable exception of neutron-capture elements, which present an overabundance of [n/Fe]0.1[n\mathrm{/Fe]}\sim0.1. The cluster's elongated morphology is associated with the internal part of its tidal tail, following the expected dynamical process of disruption. We find a significant sign of mass segregation where the most massive stars appear 1.5 times more concentrated than other stars. The cluster's overabundance of neutron-capture elements can be related to the metallicity dependence of the neutron-capture yields due to the secondary nature of these elements, predicted by some models. UBC 274 presents a high chemical homogeneity at the level of 0.030.03 dex in the sampled region of its tidal tails.Comment: Accepted by A&

    Polyphenolic Profile and Antioxidant Activity of Leaf Purified Hydroalcoholic Extracts from Seven Mexican Persea americana Cultivars

    Get PDF
    Persea americana (avocado) is a fruit consumed worldwide; however, since avocado leaves are apparently a natural ingredient that can be used as a traditional medicine, they can be a potential source of bioactive compounds. This study aimed to analyze the antioxidant activity of seven Mexican avocado leaf extracts by DPPH•, ABTS•+, and lipid peroxidation (LPO), and to identify the compoundprofilebyliquidchromatographycoupledtomassspectrometry/electronsprayionization. The highest free radical-scavenging activity was observed for Platano Delgado and Criollo 6 avocado cultivars havin IC50 values of 271.86 ± 13.69 and 269.56 ± 6.53 for DPPH• and ABTS•+ radicals, respectively, while the best result for lipid oxidation inhibition was registered in Criollo 6 cultivar extract. Inthisstudyfortyonecompoundsweredetectedinavocadoleavesofthethesevencultivars analyzed, and of these compounds, eighteen phenolics were identified for first time in such plant material. The present study demonstrated that Mexican cultivars of Persea americana possess diverse polyphenolic compounds with strong antioxidant activity, which might be useful in the food and pharmaceutical industries

    Isolation of human bone marrow mesenchymal stem cells and evaluation of their osteogenic potential

    Get PDF
    Las células madre mesenquimatosas de médula ósea humana (abreviadas hBMSCs) constituyen una fuente de células auto-renovables con alto potencial de diferenciación, comúnmente aisladas a partir de los aspirados medulares en huesos largos. Su diferenciación hacia el linaje osteogénico, por ejemplo, ha sido ampliamente utilizada para la evaluación biológica de biomateriales o matrices con aplicaciones en la ingeniería de tejidos óseos. El objetivo de este trabajo consistió en aislar hBMSCs a partir de la cabeza femoral de pacientes sometidos a artroplastia total de cadera, así como evaluar su potencial osteogénico. Brevemente, se extrajo el hueso esponjoso y se disgregó mecánicamente; las células desprendidas se cultivaron y las células no adherentes se eliminaron luego de 4 días. El potencial osteogénico se evaluó en la quinta generación de cultivo, mediante ensayos de diferenciación a 14 y 20 días donde se compararon cultivos con y sin suplementos osteogénicos. La evaluación se realizó mediante tinción con Alizarina Roja y la cuantificación de los niveles de expresión génica de los marcadores osteogénicos colágeno tipo I, osteonectinca y sialoprotiena ósea mediante RT-PCR en tiempo real. Las hBMSCs obtenidas presentaron un fenotipo no-diferenciado estable, así como la capacidad de mineralizar la matriz extracelular y expresar un fenotipo similar al osteoblasto durante la inducción osteogénica. Los tres marcadores evaluados se sobre-expresaron en los cultivos en condiciones osteogénicas, y se encontró que cambios hasta de 2X en sus niveles de expresión son relevantes para el desarrollo del proceso de diferenciación. El modelo de hBMSCS presentado podría ser utilizado para la evaluación in vitro de la osteoinductividad de diferentes biomateriales, moléculas bioactivas o matrices para ingeniería de tejidos.Human bone marrow mesenchymal stem cells (hBMSCs) comprise a cell population capable of self-renewal and multilineage differentiation commonly isolated from bone marrow aspirates of large bones. Their osteogenic potential has been extensively exploited for the biological evaluation of scaffolds or biomaterials with applications in bone tissue engineering. This work aimed to isolate hBMSCs from femoral heads of patients undergoing total hip arthroplasty and to evaluate their osteogenic potential. Briefly, the trabecular bone was extracted and mechanically disaggregated; the released cells were cultured and non-adherent cells were removed after 4 days. The osteogenic potential was evaluated at the fifth passage after 14 and 20 days of induction, comparing cultures with and without osteogenic supplements, via Alizarin red staining and the quantification of the gene expression levels of the osteogenic markers collagen type I, osteonectin and bone sialoprotein through real-time RT-PCR. The obtained hBMSCs presented a stable undifferentiated phenotype after prolonged cell culture, matrix mineralization capabilities and expression of osteoblast phenotype upon osteogenic induction. The three markers were up-regulated in cultures under osteogenic conditions and 2 fold differences in their expression levels were found to be significant for the onset of the differentiation process. The obtained hBMSCs may have applications on the in vitro evaluation of the osteoinductivity of different biomaterials, bioactive molecules or tissue engineering scaffolds

    Moving beyond disrespect and abuse: addressing the structural dimensions of obstetric violence

    Get PDF
    AbstractDuring recent decades, a growing and preoccupying excess of medical interventions during childbirth, even in physiological and uncomplicated births, together with a concerning spread of abusive and disrespectful practices towards women during childbirth across the world, have been reported. Despite research and policy-making to address these problems, changing childbirth practices has proved to be difficult. We argue that the excessive rates of medical interventions and disrespect towards women during childbirth should be analysed as a consequence of structural violence, and that the concept of obstetric violence, as it is being used in Latin American childbirth activism and legal documents, might prove to be a useful tool for addressing structural violence in maternity care such as high intervention rates, non-consented care, disrespect and other abusive practices

    Acidithiobacillia class members originating at sites within the Pacific Ring of Fire and other tectonically active locations and description of the novel genus ‘ Igneacidithiobacillus’

    Get PDF
    Recent studies have expanded the genomic contours of the Acidithiobacillia, highlighting important lacunae in our comprehension of the phylogenetic space occupied by certain lineages of the class. One such lineage is ‘Igneacidithiobacillus’, a novel genus-level taxon, represented by ‘Igneacidithiobacillus copahuensis’ VAN18-1T as its type species, along with two other uncultivated metagenome-assembled genomes (MAGs) originating from geothermally active sites across the Pacific Ring of Fire. In this study, we investigate the genetic and genomic diversity, and the distribution patterns of several uncharacterized Acidithiobacillia class strains and sequence clones, which are ascribed to the same 16S rRNA gene sequence clade. By digging deeper into this data and contributing to novel MAGs emerging from environmental studies in tectonically active locations, the description of this novel genus has been consolidated. Using state-of-the-art genomic taxonomy methods, we added to already recognized taxa, an additional four novel Candidate (Ca.) species, including ‘Ca. Igneacidithiobacillus chanchocoensis’ (mCHCt20-1TS), ‘Igneacidithiobacillus siniensis’ (S30A2T), ‘Ca. Igneacidithiobacillus taupoensis’ (TVZ-G3 TS), and ‘Ca. Igneacidithiobacillus waiarikiensis’ (TVZ-G4 TS). Analysis of published data on the isolation, enrichment, cultivation, and preliminary microbiological characterization of several of these unassigned or misassigned strains, along with the type species of the genus, plus the recoverable environmental data from metagenomic studies, allowed us to identify habitat preferences of these taxa. Commonalities and lineage-specific adaptations of the seven species of the genus were derived from pangenome analysis and comparative genomic metabolic reconstruction. The findings emerging from this study lay the groundwork for further research on the ecology, evolution, and biotechnological potential of the novel genus ‘Igneacidithiobacillus’

    Emergent Phenomena Induced by Spin-Orbit Coupling at Surfaces and Interfaces

    Full text link
    Spin-orbit coupling (SOC) describes the relativistic interaction between the spin and momentum degrees of freedom of electrons, and is central to the rich phenomena observed in condensed matter systems. In recent years, new phases of matter have emerged from the interplay between SOC and low dimensionality, such as chiral spin textures and spin-polarized surface and interface states. These low-dimensional SOC-based realizations are typically robust and can be exploited at room temperature. Here we discuss SOC as a means of producing such fundamentally new physical phenomena in thin films and heterostructures. We put into context the technological promise of these material classes for developing spin-based device applications at room temperature

    Development of an estimative model for the optimal tack coat dosage based on aggregate gradation of hot mix asphalt pavements

    Get PDF
    In this work the performance of tack coats on asphalt pavement layers is analysed. Adjustment models based on experimental measurements were implemented, relating surface layer macro-texture and aggregate content larger than 8 mm. The best fits were obtained with a Gompertz model, which follows the expected physical macro-texture changes outside the test range. Shear strength was analysed, through prediction curves of each evaluated tack coat dosage, with an optimum tack coat performance for aggregate contents larger than 8 mm between 45% and 50%, and no relevant influence of the tack coat dosage used.The authors would like to acknowledge the support provided by the Technologic Research Construction Group (GITECO) and the Group of Roads of Santander at Cantabria University for the development of tests and samples. We would also like to thank the company Emilio Bolado S.L. and the Society for the Development of Cantabria Region (SODERCAN) for the material provided, and the DID Research Department from the Austral University of Chile for the support
    corecore