2,571 research outputs found

    Recommendations for Child Play Areas

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    Design guide for the planning, programming and design of children\u27s outdoor play environments. Includes 75 patterns for a range of children\u27s play areas imbedded in a tiered park system and in conjunction with recreation, community and educational facilities. Based on current research information. Received an Award for Applied Research in 1980 from Progressive Architecture. Reprinted 1983, with new photographs in 1985, 1988, and in 1991. Highly illustrated.https://dc.uwm.edu/caupr_mono/1033/thumbnail.jp

    Recommendations for Child Care Centers

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    Design guide for planning, programming and designing different types of child care facilities. Includes 115 patterns for the policy, planning and design of large centers, neighborhood centers and family day-care homes. Based on current research information. Highly illustrated with photographs and sketches. Received an Award for Applied Research from Progressive Architecture, 1980, and received the 1980 UWM Foundation Research Award. Reprinted 1981, with new photographs in 1984, 1988 and in 1991. Revised edition 1994.https://dc.uwm.edu/caupr_mono/1032/thumbnail.jp

    A candidate for a background independent formulation of M theory

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    A class of background independent membrane field theories are studied, and several properties are discovered which suggest that they may play a role in a background independent form of M theory. The bulk kinematics of these theories are described in terms of the conformal blocks of an algebra G on all oriented, finite genus, two-surfaces. The bulk dynamics is described in terms of causal histories in which time evolution is specified by giving amplitudes to certain local changes of the states. Holographic observables are defined which live in finite dimensional states spaces associated with boundaries in spacetime. We show here that the natural observables in these boundary state spaces are, when G is chosen to be Spin(D) or a supersymmetric extension of it, generalizations of matrix model coordinates in D dimensions. In certain cases the bulk dynamics can be chosen so the matrix model dynamics is recoverd for the boundary observables. The bosonic and supersymmetric cases in D=3 and D=9 are studied, and it is shown that the latter is, in a certain limit, related to the matrix model formulation of M theory. This correspondence gives rise to a conjecture concerning a background independent form of M theory in terms of which excitations of the background independent membrane field theory that correspond to strings and D0 branes are identified.Comment: Latex 46 pages, 21 figures, new results included which lead to a modification of the statement of the basic conjecture. Presentation improve

    Homologous Flares and Magnetic Field Topology in Active Region NOAA 10501 on 20 November 2003

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    We present and interpret observations of two morphologically homologous flares that occurred in active region (AR) NOAA 10501 on 20 November 2003. Both flares displayed four homologous H-alpha ribbons and were both accompanied by coronal mass ejections (CMEs). The central flare ribbons were located at the site of an emerging bipole in the center of the active region. The negative polarity of this bipole fragmented in two main pieces, one rotating around the positive polarity by ~ 110 deg within 32 hours. We model the coronal magnetic field and compute its topology, using as boundary condition the magnetogram closest in time to each flare. In particular, we calculate the location of quasiseparatrix layers (QSLs) in order to understand the connectivity between the flare ribbons. Though several polarities were present in AR 10501, the global magnetic field topology corresponds to a quadrupolar magnetic field distribution without magnetic null points. For both flares, the photospheric traces of QSLs are similar and match well the locations of the four H-alpha ribbons. This globally unchanged topology and the continuous shearing by the rotating bipole are two key factors responsible for the flare homology. However, our analyses also indicate that different magnetic connectivity domains of the quadrupolar configuration become unstable during each flare, so that magnetic reconnection proceeds differently in both events.Comment: 24 pages, 10 figures, Solar Physics (accepted

    The evolution of writhe in kink-unstable flux ropes and erupting filaments

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    Copyright © 2014 IOP Publishing Ltd. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence (http://creativecommons.org/licenses/by/3.0/). Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.The helical kink instability of a twisted magnetic flux tube has been suggested as a trigger mechanism for solar filament eruptions and coronal mass ejections (CMEs). In order to investigate if estimations of the pre-emptive twist can be obtained from observations of writhe in such events, we quantitatively analyze the conversion of twist into writhe in the course of the instability, using numerical simulations. We consider the line tied, cylindrically symmetric Gold–Hoyle flux rope model and measure the writhe using the formulae by Berger and Prior which express the quantity as a single integral in space. We find that the amount of twist converted into writhe does not simply scale with the initial flux rope twist, but depends mainly on the growth rates of the instability eigenmodes of higher longitudinal order than the basic mode. The saturation levels of the writhe, as well as the shapes of the kinked flux ropes, are very similar for considerable ranges of initial flux rope twists, which essentially precludes estimations of pre-eruptive twist from measurements of writhe. However, our simulations suggest an upper twist limit of ~6π for the majority of filaments prior to their eruption.European Commission’s Seventh Framework ProgrammeScience & Technology Facilities Council (STFC)Hungarian Researc

    Interplay of Turbulence and Proton-Microinstability Growth in Space Plasmas

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    Both kinetic instabilities and strong turbulence have potential to impact the behavior of space plasmas. To assess effects of these two processes we compare results from a 3 dimensional particle-in-cell (PIC) simulation of collisionless plasma turbulence against observations by the MMS spacecraft in the terrestrial magnetosheath and by the Wind spacecraft in the solar wind. The simulation develops coherent structures and anisotropic ion velocity distributions that can drive micro-instabilities. Temperature-anisotropy driven instability growth rates are compared with inverse nonlinear turbulence time scales. Large growth rates occur near coherent structures; nevertheless linear growth rates are, on average, substantially less than the corresponding nonlinear rates. This result casts some doubt on the usual basis for employing linear instability theory, and raises questions as to why the linear theory appears to work in limiting plasma excursions in anisotropy and plasma beta.Comment: Under revie

    CD5 expression promotes IL-10 production through activation of the MAPK/Erk pathway and upregulation of TRPC1 channels in B lymphocytes.

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    CD5 is constitutively expressed on T cells and a subset of mature normal and leukemic B cells in patients with chronic lymphocytic leukemia (CLL). Important functional properties are associated with CD5 expression in B cells, including signal transducer and activator of transcription 3 activation, IL-10 production and the promotion of B-lymphocyte survival and transformation. However, the pathway(s) by which CD5 influences the biology of B cells and its dependence on B-cell receptor (BCR) co-signaling remain unknown. In this study, we show that CD5 expression activates a number of important signaling pathways, including Erk1/2, leading to IL-10 production through a novel pathway independent of BCR engagement. This pathway is dependent on extracellular calcium (Ca2+) entry facilitated by upregulation of the transient receptor potential channel 1 (TRPC1) protein. We also show that Erk1/2 activation in a subgroup of CLL patients is associated with TRPC1 overexpression. In this subgroup of CLL patients, small inhibitory RNA (siRNA) for CD5 reduces TRPC1 expression. Furthermore, siRNAs for CD5 or for TRPC1 inhibit IL-10 production. These findings provide new insights into the role of CD5 in B-cell biology in health and disease and could pave the way for new treatment strategies for patients with B-CLL

    Effect of Gene Therapy on Visual Function in Leber's Congenital Amaurosis

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    Early-onset, severe retinal dystrophy caused by mutations in the gene encoding retinal pigment epithelium–specific 65-kD protein (RPE65) is associated with poor vision at birth and complete loss of vision in early adulthood. We administered to three young adult patients subretinal injections of recombinant adeno-associated virus vector 2/2 expressing RPE65 complementary DNA (cDNA) under the control of a human RPE65 promoter. There were no serious adverse events. There was no clinically significant change in visual acuity or in peripheral visual fields on Goldmann perimetry in any of the three patients. We detected no change in retinal responses on electroretinography. One patient had significant improvement in visual function on microperimetry and on dark-adapted perimetry. This patient also showed improvement in a subjective test of visual mobility. These findings provide support for further clinical studies of this experimental approach in other patients with mutant RPE65. (ClinicalTrials.gov number, NCT00643747.)Supported by grants from the U.K. Department of Health, the British Retinitis Pigmentosa Society, and the Special Trustees of Moorfields Eye Hospital, and by the Sir Jules Thorn Charitable Trust, the Wellcome Trust, the European Union (EVI-Genoret and Clinigene programs), the Medical Research Council, Foundation Fighting Blindness, Fight for Sight, the Ulverscroft Foundation, Fighting Blindness (Ireland), Moorfields Eye Hospital, and Institute of Ophthalmology Biomedical Research Centre for Ophthalmology, University College London

    Association between Use of HMG CoA Reductase Inhibitors and Mortality in HIV-Infected Patients

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    HIV infection is a disease associated with chronic inflammation and immune activation. Antiretroviral therapy reduces inflammation, but not to levels in comparable HIV-negative individuals. The HMG-coenzyme A reductase inhibitors (statins) inhibit several pro-inflammatory processes and suppress immune activation, and are a logical therapy to assess for a possible salutary effect on HIV disease progression and outcomes.Eligible patients were patients enrolled in the Johns Hopkins HIV Clinical Cohort who achieved virologic suppression within 180 days of starting a new highly active antiretroviral therapy (HAART) regimen after January 1, 1998. Assessment was continued until death in patients who maintained a virologic suppression, with right-censoring of their follow-up time if they had an HIV RNA > 500 copies/ml. Cox proportional hazards regression was used to assess statin use as a time-varying covariate, as well as other demographic and clinical factors.A total of 1538 HIV-infected patients fulfilled eligibility criteria, of whom 238 (15.5%) received a statin while taking HAART. There were 85 deaths (7 in statin users, 78 in non-users). By multivariate Cox regression, statin use was associated with a relative hazard of 0.33 (95% CI: 0.14, 0.76; P =  0.009) after adjusting for CD4, HIV-1 RNA, hemoglobin and cholesterol levels at the start of HAART, age, race, HIV risk group, prior use of ART, year of HAART start, NNRTI vs. PI-based ART, prior AIDS-defining illness, and viral hepatitis coinfection. Malignancy, non-AIDS-defining infection and liver failure were particularly prominent causes of death.Statin use was associated with significantly lower hazard of dying in these HIV-infected patients who were being effectively treated with HAART as determined by virologic suppression. Our results suggest the need for confirmation in other observational cohorts, and if confirmed, the need for a clinical trial of statin use in HIV infection
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