Abundance, Major Element Composition and Size of Components and Matrix in CV, CO and Acfer 094 Chondrites

The relative abundances and chemical compositions of the macroscopic components or "inclusions" (chondrules and refractory inclusions) and fine-grained mineral matrix in chondritic meteorites provide constraints on astrophysical theories of inclusion formation and chondrite accretion. We present new techniques for analysis of low count per pixel Si, Mg, Ca, Al, Ti and Fe x-ray intensity maps of rock sections, and apply them to large areas of CO and CV chondrites, and the ungrouped Acfer 094 chondrite. For many thousands of manually segmented and type-identified inclusions, we are able to assess, pixel-by-pixel, the major element content of each inclusion. We quantify the total fraction of those elements accounted for by various types of inclusion and matrix. Among CO chondrites, both matrix and inclusion Mg to Si ratios approach the solar (and bulk CO) ratio with increasing petrologic grade, but Si remains enriched in inclusions relative to matrix. The oxidized CV chondrites with higher matrix-inclusion ratios exhibit more severe aqueous alteration (oxidation), and their excess matrix accounts for their higher porosity relative to reduced CV chondrites. Porosity could accommodate an original ice component of matrix as the direct cause of local alteration of oxidized CV chondrites. We confirm that major element abundances among inclusions differ greatly, across a wide range of CO and CV chondrites. These abundances in all cases add up to near-chondritic (solar) bulk abundance ratios in these chondrites, despite wide variations in matrix-inclusion ratios and inclusion sizes: chondrite components are complementary. This "complementarity" provides a robust meteoritic constraint for astrophysical disk models

The inwardly rectifying K+ channel KIR7.1 controls uterine excitability throughout pregnancy

Abnormal uterine activity in pregnancy causes a range of important clinical disorders, including preterm birth, dysfunctional labour and post-partum haemorrhage. Uterine contractile patterns are controlled by the generation of complex electrical signals at the myometrial smooth muscle plasma membrane. To identify novel targets to treat conditions associated with uterine dysfunction, we undertook a genome-wide screen of potassium channels that are enriched in myometrial smooth muscle. Computational modelling identified Kir7.1 as potentially important in regulating uterine excitability during pregnancy. We demonstrate Kir7.1 current hyper-polarizes uterine myocytes and promotes quiescence during gestation. Labour is associated with a decline, but not loss, of Kir7.1 expression. Knockdown of Kir7.1 by lentiviral expression of miRNA was sufficient to increase uterine contractile force and duration significantly. Conversely, overexpression of Kir7.1 inhibited uterine contractility. Finally, we demonstrate that the Kir7.1 inhibitor VU590 as well as novel derivative compounds induces profound, long-lasting contractions in mouse and human myometrium; the activity of these inhibitors exceeds that of other uterotonic drugs. We conclude Kir7.1 regulates the transition from quiescence to contractions in the pregnant uterus and may be a target for therapies to control uterine contractility

A História da Alimentação: balizas historiográficas

Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

Naltrexone maintenance therapy with pellet implantation as an aid for relapse prevention of heroin dependent individuals : a South African perspective

Heroin use and dependency is a growing concern within South Africa, individuals face difficulty in remaining abstinent from the use of heroin due to constant relapse. The opioid antagonist known as the naltrexone pellet implant offers an alternative form of aid to relapse prevention in the recovery and abstinence from heroin dependency. This qualitative study explored the subjective experiences and perceptions of heroin dependent individuals, that made use of the naltrexone pellet implant. This study was rooted in the interpretive, qualitative paradigm where a phenomenological research design was used. Participants were selected using a purposive, snowball sampling technique and four individuals who had made use of the naltrexone pellet implant for the aid in heroin dependency for a minimum of three-months were interviewed. Interpretative Phenomenological Analysis (IPA) was used to extract recurrent themes across participants. The findings suggested that the use of the naltrexone pellet implant was beneficial in the aid for relapse prevention from heroin use. Furthermore, the exploration of difficulties that were faced in remaining abstinent, the attempt to make use of the naltrexone pellet implant and the physical and psychological aspects regarding the use of this alternative method of remaining abstinent were explored in this study.PsychologyM.A. (Psychology (Research Consultation)