684 research outputs found

    Spiritual Formation for Ministry in the Context of the Anglican Church of Hong Kong

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    Reflecting on his experience teaching ‘Spirituality and the Practice of Ministry’ in a Hong Kong Episcopal Seminary, John Kater describes the joys and challenges of his experience as a Western theologian in an Asian context

    Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic Motion

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    We report on Kerr nonlinearity and dispersive optical bistability of a Fabry-Perot optical resonator due to the displacement of ultracold atoms trapped within. In the driven resonator, such collective motion is induced by optical forces acting upon up to 10510^5 87^{87}Rb atoms prepared in the lowest band of a one-dimensional intracavity optical lattice. The longevity of atomic motional coherence allows for strongly nonlinear optics at extremely low cavity photon numbers, as demonstrated by the observation of both branches of optical bistability at photon numbers below unity.Comment: 4 pages, 3 figures. Modifed following reviewer comment

    Collimated, single-pass atom source from a pulsed alkali metal dispenser for laser-cooling experiments

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    We have developed an improved scheme for loading atoms into a magneto-optical trap (MOT) from a directed alkali metal dispenser in < 10^-10 torr ultra-high vacuum conditions. A current-driven dispenser was surrounded with a cold absorbing "shroud" held at < 0 C, pumping rubidium atoms not directed into the MOT. This nearly eliminates background alkali atoms and reduces the detrimental rise in pressure normally associated with these devices. The system can be well-described as a current-controlled, rapidly-switched, two-temperature thermal beam, and was used to load a MOT with 3 x 10^8 atoms.Comment: 5 pages, 4 figure

    Functional conservation of MADS-box factors controlling floral organ identity in rice and Arabidopsis

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    Studies on MADS-box genes in Arabidopsis and other higher eudicotyledonous flowering plants have shown that they are key regulators of flower development. Since Arabidopsis and monocotyledonous rice are distantly related plant species it is interesting to investigate whether the floral organ identity factors have been conserved in their functions, and if not, to understand the differences. Arabidopsis and rice are very suitable for these studies since they are both regarded as models for plant functional genomics. Both their genomes are sequenced and tools are available for the analysis of gene function. These developments have accelerated experiments and increased our knowledge on rice gene function. Therefore it is the right moment to perform a comparative analysis on MADS-box factors controlling floral organ identity as reported in this review

    Perfil característico das atividades 17-hidroxilase e 17,20-liase reveladas por meio do metaboloma de esteroides urinários de pacientes com deficiência de CYP17

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    OBJECTIVES: (1) Characterize serum (S) and urinary (U) steroid metabolites in complete CYP17 deficiency (cCYP17D); (2) analyze the relative 17α-hydroxylase (17OH) and 17,20-lyase (17,20L) activities in vivo; and (3) comparedata from the two most prevalent mutations in Brazil. SUBJECTS AND METHODS: 20 genotyped cCYP17D patients from a previously reported cohort were homozygous for W406R or R362C; 11 controls were CYP17 wild types (WT). WT and cCYP17D patients had S and U samples drawn to measure: cortisol (F), corticosterone (B), deoxycorticosterone (DOC), 18OH-B, 18OH-DOC, and 17OHP; and tetrahydro (TH)-B, THA, THDOC, THF+5α-THF, TH-cortisone, androsterone, etiocholanolone, 5-pregnenediol, 17OH-pregnenolone and pregnanetriol. RESULTS: Compared to WT, cCYP17D patients had marked elevations of B, DOC, 18OH-B and 18OH-DOC, whereas 17OHP, F and adrenal androgens (AA) were reduced; U steroids parallel S findings. Metabolite ratios revealed that both 17OH and 17,20L activities were impaired in cCYP17D. There were nodifferences between W406R andR362C mutations. CONCLUSIONS: cCYP17D patients show parallel overproduction/overexcretion of 17-deoxysteroids, and marked reduction of F and AA. In addition to 17OH, 17,20-L activity was also impaired in cCYP17D. W406 and R362C mutations disclose similar Sand U patterns.OBJETIVOS: (1) Caracterizar os esteroides séricos (S) e urinários (U) na deficiência completa da CYP17 (DcCYP17); (2) analisar as atividades da 17α-hidroxilase (17OH) e 17,20-liase (17, 20 L) in vivo; e (3) comparar as duas mutações mais prevalentes no Brasil. SUJEITOS E MÉTODOS: 20 pacientes genotipados para a DcCYP17, de uma coorte anterior, eram homozigotos para W406R ou R362C (8 cada); 11 controles eram CYP17 wild types (WT). Amostras de S e U foram colhidas dos WT e pacientes para dosagem de: cortisol (F), corticosterona (B), deoxicorticosterona (DOC), 18-OH-B, 18OH-DOC e 17OHP; e tetraidro(TH)-B, THA, TH-DOC, THF+5α-THF, THE, androsterona, etiocolanolona, 5-pregnenediol, 17OH-pregnenolona e pregnanetriol. RESULTADOS: Comparados aos WT, os pacientes com DcCYP17 revelaram elevações acentuadas de B, DOC, 18OHB e 18OHDOC, enquanto 17OHP, F e andrógenos adrenais (AA) estavam reduzidos. Os esteroides na U acompanham os achados no S. As relações de metabólitos mostraram que as atividades de 17OH e 17,20L estavam reduzidas em pacientes com DcCYP17. Não houve diferenças entre pacientes com as mutações W406R e R362C. CONCLUSÕES: Na DcCYP17, a produção e a excreção dos 17-deoxiesteroides estão aumentadas em paralelo, em contraste com a reduzida produção/excreção de F e AA. As atividades da 17OH e 17,20-L estão diminuídas na DcCYP17. As mutações W406 e R362C apresentam achados semelhantes em S e U.Universidade Federal de São Paulo (UNIFESP) Department of Medicine Division of Endocrinology and MetabolismUniversity of Texas Southwestern Medical Center Department of Clinical SciencesUniversity of Birmingham Division of Medical SciencesUNIFESP, Department of Medicine Division of Endocrinology and MetabolismSciEL

    Gynoecium size and ovule number are interconnected traits that impact seed yield

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    Angiosperms form the biggest group of land plants and display an astonishing diversity of floral structures. The development of the flowers greatly contributed to the evolutionary success of the angiosperms as they guarantee efficient reproduction with the help of either biotic or abiotic vectors. The female reproductive part of the flower is the gynoecium (also called pistil). Ovules arise from meristematic tissue within the gynoecium. Upon fertilization, these ovules develop into seeds while the gynoecium turns into a fruit. Gene regulatory networks involving transcription factors and hormonal communication regulate ovule primordium initiation, their spacing on the placenta, and ovule development. Ovule number and gynoecium size are usually correlated and several genetic factors that impact these traits have been identified. Understanding and fine-tuning the gene regulatory networks influencing ovule number and pistil length opens up strategies for crop yield improvement, which is pivotal in light of a rapidly growing world population. In this review, we present an overview of the current knowledge of the genes and hormones involved in determining ovule number and gynoecium size. We propose a model for the gene regulatory network that guides the developmental processes that determine seed yield
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