229 research outputs found

    Letter from Martin S. Garretson to A. C. Van Raalte

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    Martin S. Garretson wrote Rev. Albertus C. Van Raalte about property matters. Could Garretson have been a brother of Rev. John Garretson who was secretary of the Board of Domestic Missions of the Reformed Protestant Dutch Church, 1849-1859? [Note that in this document, the gentleman\u27s e look like i\u27]https://digitalcommons.hope.edu/vrp_1860s/1053/thumbnail.jp

    A double-slit `which-way' experiment on the complementarity--uncertainty debate

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    A which-way measurement in Young's double-slit will destroy the interference pattern. Bohr claimed this complementarity between wave- and particle behaviour is enforced by Heisenberg's uncertainty principle: distinguishing two positions a distance s apart transfers a random momentum q \sim \hbar/s to the particle. This claim has been subject to debate: Scully et al. asserted that in some situations interference can be destroyed with no momentum transfer, while Storey et al. asserted that Bohr's stance is always valid. We address this issue using the experimental technique of weak measurement. We measure a distribution for q that spreads well beyond [-\hbar/s, \hbar/s], but nevertheless has a variance consistent with zero. This weakvalued momentum-transfer distribution P_{wv}(q) thus reflects both sides of the debate.Comment: 13 pages, 4 figure

    A New Perspective on Cosmic Coincidence Problems

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    Cosmological data suggest that we live in an interesting period in the history of the universe when \rho_\Lambda \sim \rho_M \sim \rho_R. The occurence of any epoch with such a "triple coincidence" is puzzling, while the question of why we happen to live during this special epoch is the "Why now?" problem. We introduce a framework which makes the triple coincidence inevitable; furthermore, the ``Why now?'' problem is transformed and greatly ameliorated. The framework assumes that the only relevant mass scales are the electroweak scale, M_{EW}, and the Planck scale, M_{Pl}, and requires \rho_\Lambda^{1/4} \sim M_{EW}^2/M_{Pl} parametrically. Assuming that the true vacuum energy vanishes, we present a simple model where a false vacuum energy yields a cosmological constant of this form.Comment: 5 pages, 1 figure, uses psfig. Refs added, slightly enhance

    Elevated transgelin reduces function of endothelial colony forming cells from gestational diabetic pregnancies

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    poster abstractFetal exposure to maternal diabetes predisposes children to future complications including hypertension and cardiovascular disease. A key mechanism by which these complications are thought to occur and persist is through the functional impairment of vascular progenitor cells, including endothelial colony forming cells (ECFCs). Previously, we showed that ECFCs exposed to gestational diabetes exhibit functional deficits, such as impaired vessel formation, but also differential gene expression compared to uncomplicated controls. One gene that was confirmed to be significantly upregulated in ECFCS from diabetic pregnancies was transgelin, an actin-binding smooth muscle protein. However, the functional consequences of increased transgelin in ECFCs are unknown. Therefore, to determine if transgelin is sufficient and required to induce dysfunction of ECFCs from diabetic pregnancies, transgelin protein levels were manipulated using genetic methods. Specifically, lentiviral overexpression and siRNA knockdown techniques were used in ECFCs from control and diabetic pregnancies respectively. Network formation assays and trans-well migration assays were performed to assess whether alteration of transgelin levels impact ECFC vasculogenesis and migration. Decreasing transgelin expression in diabetes-exposed ECFCs increased network formation (n=15, p<0.05) and cell migration (n=12, p<0.05). Conversely, overexpression of transgelin in ECFCs from uncomplicated pregnancies decreased network formation (n=12, p<0.05). Additional studies are underway to further elucidate intracellular signaling altered as a result of increased transgelin expression in diabetes-exposed ECFCs. Delineating the mechanisms underlying ECFC functional deficits will aid in the understanding of how and why chronic vascular complications persist in children born to mothers with diabetes

    Tim Bartness, Ph.D. (1953-2015)

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    Tim Bartness (Fig. 1) was a friend, mentor, collaborator and leader to many scientists, younger and older, across a variety of disciplines. He died September 24, 2015 at the age of 62 after a one-year battle with multiple myeloma. Tim not only helped educate many of us, but also challenged us to think critically and to laugh heartily about both the bad and the good we experienced in life. Tim was dedicated to science and to those around him. He worked diligently on his research right up the very end until he no longer could

    Dark Energy in an Axion Model with Explicit Z(N) Symmetry Breaking

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    We point out that a well known axion model with an explicit Z(N) symmetry breaking term predicts both dark energy and cold dark matter. We estimate the parameters of this model which fit the observed densities of the dark components of the universe. We find that the parameters do not conflict with any observations.Comment: 5 pages, minor change

    Comparative Study of the Standard Fluorescent Antibody to Membrane Antigen (FAMA) Assay and a Flow Cytometry-Adapted FAMA Assay To Assess Immunity to Varicella-Zoster Virus

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    A flow cytometry-adapted fluorescent antibody to membrane antigen (FAMA) assay to detect IgG antibodies against varicella-zoster virus (VZV) was developed and tested in 62 serum samples, showing 90.32% accuracy obtained from a receiver operating characteristic (ROC) curve with a 0.9125 (95% confidence interval [CI], 0.829 to 1.00) area below the curve compared to the result with standard FAMA.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fed Univ São Paulo UNIFESP EPM, Div Pediat Infect Dis, BR-04040000 São Paulo, BrazilColumbia Univ, Dept Pediat, Coll Phys & Surg, New York, NY 10027 USAFed Univ São Paulo UNIFESP EPM, Div Pediat Infect Dis, BR-04040000 São Paulo, BrazilCAPES: 0108-08-1Web of Scienc

    Transgelin Induces Dysfunction of Fetal Endothelial Colony-Forming Cells From Gestational Diabetic Pregnancies

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    Fetal exposure to gestational diabetes mellitus (GDM) predisposes children to future health complications including hypertension and cardiovascular disease. A key mechanism by which these complications occur is through the functional impairment of vascular progenitor cells, including endothelial colony-forming cells (ECFCs). Previously, we showed that fetal ECFCs exposed to GDM have decreased vasculogenic potential and altered gene expression. In this study, we evaluate whether transgelin (TAGLN), which is increased in GDM-exposed ECFCs, contributes to vasculogenic dysfunction. TAGLN is an actin-binding protein involved in the regulation of cytoskeletal rearrangement. We hypothesized that increased TAGLN expression in GDM-exposed fetal ECFCs decreases network formation by impairing cytoskeletal rearrangement resulting in reduced cell migration. To determine if TAGLN is required and/or sufficient to impair ECFC network formation, TAGLN was reduced and overexpressed in ECFCs from GDM and uncomplicated pregnancies, respectively. Decreasing TAGLN expression in GDM-exposed ECFCs improved network formation and stability as well as increased migration. In contrast, overexpressing TAGLN in ECFCs from uncomplicated pregnancies decreased network formation, network stability, migration, and alignment to laminar flow. Overall, these data suggest that increased TAGLN likely contributes to the vasculogenic dysfunction observed in GDM-exposed ECFCs, as it impairs ECFC migration, cell alignment, and network formation. Identifying the molecular mechanisms underlying fetal ECFC dysfunction following GDM exposure is key to ascertain mechanistically the basis for cardiovascular disease predisposition later in life

    Electromagnetic Origin of the CMB Anisotropy in String Cosmology

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    In the inflationary scenarios suggested by string theory, the vacuum fluctuations of the electromagnetic field can be amplified by the time-evolution of the dilaton background, and can grow large enough to explain both the origin of the cosmic magnetic fields and of the observed CMB anisotropy. The normalization of the perturbation spectrum is fixed, and implies a relation between the perturbation amplitude at the COBE scale and the spectral index nn. Working within a generic two-parameter family of backgrounds, a large scale anisotropy ΔT/T≃10−5\Delta T/T\simeq 10^{-5} is found to correspond to a spectral index in the range n≃1.11−1.17n\simeq 1.11 - 1.17.Comment: 11 pages, LATE
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