1,601 research outputs found

    Orbital motion of the young brown dwarf companion TWA 5 B

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    With more adaptive optics images available, we aim at detecting orbital motion for the first time in the system TWA 5 A+B. We measured separation and position angle between TWA 5 A and B in each high-resolution image available and followed their change in time, because B should orbit around A. The astrometric measurement precision is about one milli arc sec. With ten year difference in epoch, we can clearly detect orbital motion of B around A, a decrease in separation by ~ 0.0054 arc sec per year and a decrease in position angle by ~ 0.26 degrees per year. TWA 5 B is a brown dwarf with ~ 25 Jupiter masses (Neuh\"auser et al. 2000), but having large error bars (4 to 145 Jupiter masses, Neuh\"auser et al. 2009). Given its large projected separation from the primary star, ~ 86 AU, and its young age ~ 10 Myrs), it has probably formed star-like, and would then be a brown dwarf companion. Given the relatively large changes in separation and position angle between TWA 5 A and B, we can conclude that they orbit around each other on an eccentric orbit. Some evidence is found for a curvature in the orbital motion of B around A - most consistent with an elliptic (e=0.45) orbit. Residuals around the best-fit ellipse are detected and show a small-amplitude (~ 18 mas) periodic sinusoid with ~ 5.7 yr period, i.e., fully consistent with the orbit of the inner close pair TWA 5 Aa+b. Measuring these residuals caused by the photocenter wobble - even in unresolved images - can yield the total mass of the inner pair, so can test theoretical pre-main sequence models.Comment: 6 pages, 4 figures, accepted for publication in A&A; corrected typo in amplitude below Fig.

    Poupança Individual de Aposentadoria : PIÁ

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    Este artigo apresenta o conceito da poupan\ue7a individual de aposentadoria \u2013 PI\uc1 \u2013 adaptado \ue0 realidade brasileira. Dentro de uma estrutura atuarial, a plataforma do Tesouro Direto \ue9 utilizada como fundamento para a implementa\ue7\ue3o de um sistema apto a proteger os valores dos participantes, evitando-se os hist\uf3ricos de m\ue1-gest\ue3o, corrup\ue7\ue3o, falta de transpar\ueancia ou altas taxas de administra\ue7\ue3o inerentes ao sistema de previd\ueancia privada brasileiro ou mundial. Outro aspecto \ue9 a isen\ue7\ue3o tribut\ue1ria, hoje existente para grandes investidores, que seria estendida para esta plataforma, estimulando a eleva\ue7\ue3o da taxa de poupan\ue7a nacional e diminuindo a depend\ueancia do pa\ueds do capital estrangeiro.This paper presents the concept of individual savings accounts for retirement adapted to the Brazilian reality. Using actuarial framework to corroborate the technical and scientific aspects of the idea, the platform of the \u201cTesouro Direto\u201d in Brazil is taken as the rationale to implement a system that can protect the monies of participants, avoiding the historic mismanagement, corruption, graft, lack of transparency or high fees that are related to the private pension system in Brazil and in the world. Another aspect is the existing tax exemption for large investors, which would be extended to this platform. This should foster the increase of the national savings rate and reduce the country's dependence on foreign capital

    Infrared Space Observatory Polarimetric Imaging of the Egg Nebula (RAFGL 2688)

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    We present polarimetric imaging of the protoplanetary nebula RAFGL 2688 obtained at 4.5 microns with the Infrared Space Observatory (ISO). We have deconvolved the images to remove the signature of the point spread function of the ISO telescope, to the extent possible. The deconvolved 4.5 micron image and polarimetric map reveal a bright point source with faint, surrounding reflection nebulosity. The reflection nebula is brightest to the north-northeast, in agreement with previous ground- and space-based infrared imaging. Comparison with previous near-infrared polarimetric imaging suggests that the polarization of starlight induced by the dust grains in RAFGL 2688 is more or less independent of wavelength between 2 microns and 4.5 microns. This, in turn, indicates that scattering dominates over thermal emission at wavelengths as long as ~5 microns, and that the dust grains have characteristic radii < 1 micron.Comment: 27 pages, 9 figures; to appear in the Astronomical Journal, May 2002 issu

    Pramipexole for the treatment of depressive symptoms in patients with Parkinson disease: a randomized, double blind, placebo controlled trial

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    Background: Depression is common in patients with Parkinson's disease, but evidence on the efficacy of antidepressants in this population is lacking. Because depression in patients with Parkinson's disease might be related to dopaminergic dysfunction, we aimed to assess the efficacy of the dopamine agonist pramipexole for treatment of depressive symptoms in patients with Parkinson's disease. METHODS: We did a 12-week randomised, double-blind, placebo-controlled (1:1 ratio) trial of pramipexole (0.125-1.0 mg three times per day) compared with placebo in patients with mild-to-moderate Parkinson's disease. Patients from 76 centres in 12 European countries and South Africa were included if they were on stable antiparkinsonian therapy without motor fluctuations and had depressive symptoms (15-item geriatric depression scale score > or =5 and unified Parkinson's disease rating scale [UPDRS] part 1 depression item score > or =2). Patients were randomly assigned by centre in blocks of four by use of a randomisation number generating system. Clinical monitors, the principal investigator, and patients were masked to treatment allocation. The primary endpoint was change in Beck depression inventory (BDI) score and all treated patients who had at least one post-baseline efficacy assessment were included in the primary analysis. We also did a pre-specified path analysis with regression models to assess the relation between BDI and UPDRS part 3 (motor score) changes. This trial is registered with ClinicalTrials.gov, number NCT00297778, and EudraCT, number 2005-003788-22. FINDINGS: Between March, 2006, and February, 2008, we enrolled 323 patients. Of 296 patients randomly assigned to pramipexole or placebo, 287 were included in the primary analysis: 139 in the pramipexole group and 148 in the placebo group. BDI scores decreased by an adjusted mean 5.9 (SE 0.5) points in the pramipexole group and 4.0 (0.5) points in the placebo group (difference 1.9, 95% CI 0.5-3.4; p=0.01, ANCOVA). The UPDRS motor score decreased by an adjusted mean 4.4 (0.6) points in the pramipexole group and 2.2 (0.5) points in the placebo group (difference 2.2, 95% CI 0.7-3.7; p=0.003, ANCOVA). Path analysis showed the direct effect of pramipexole on depressive symptoms accounted for 80% of total treatment effect (p=0.04). Adverse events were reported in 105 of 144 patients in the pramipexole group and 101 of 152 in the placebo group. Adverse events in the pramipexole group were consistent with the known safety profile of the drug. INTERPRETATION: Pramipexole improved depressive symptoms in patients with Parkinson's disease, mainly through a direct antidepressant effect. This effect should be considered in the clinical management of patients with Parkinson's disease

    Исследование влияния ионизирующего излучения высокоэнергетических ионов гелия на процессы формирования протон-проводящих свойств полимерных фторсодержащих функциональных трековых мембран

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    Объект исследования-полимерная пленка ПВДФ и прививаемый мономер–стирол, обладающий сшивающими свойствами при модификации. Цель работы–синтез протон-проводящих мембран путем модифицирования пленок ПВДФ сульфированным полистиролом и установление влияния наполнителей на их транспортные и физико-химические свойства. В процессе проводились теоретические и экспериментальные работы по радиационно-химической полимеризации стирола в матрицу ПВДФ с последующим сульфированием полимерного композита, по определению обменной емкости и протонной проводимости мембран. В результате получена ППМ путем матричной полимеризации ПВДФ ионизующимся мономером. Результаты представляют интерес для понимания процессов матричной полимеризации ионизующихся мономеров и могут являться основой для создания полимерных сисThe object of study-polymer film PVDF and grafting monomer is styrene, having crosslinking properties when enchanted. Purpose–synthesis of proton-conducting membranes by the modification of the PVDF films of sulfonated polystyrene and evaluation of the influence of fillers on the transport and their physico-chemical properties. The process was carried out work on radiation-chemical polymerization of styrene in a matrix of PVDF with subsequent by sulfonation polymer composite, by definition, exchange capacity and proton conductivity of the membranes. The result is PCM by matrix polymerization of PVDF ionizable monomer. The results are of interest for understanding the processes matrix polymerization of ionizable monomers and may be the basis for the creation of polymer systems

    Equitable Allocation of COVID-19 Vaccines: An Analysis of the Initial Allocation Plans of CDC\u27s Jurisdictions with Implications for Disparate Impact Monitoring

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    Major global and national vaccine allocation guidelines urge planners to allocate vaccines in ways that recognize, and ideally reduce, existing societal inequities within countries. However, allocation plans of the US will be determined individually by each of the CDC’s 64 jurisdictions (states, the District of Columbia, five cities, and territories). We analyzed whether jurisdictions have incorporated novel approaches to reduce inequity, based on plans published by the CDC in early November 2020 (63 summaries [98% of all jurisdictions] and 47 full guidance documents [73% of all, including all 50 states]). Eighteen states adopted a novel proposal to use a disadvantage index to allocate vaccines more equitably, for five types of equity goals: 1) to prioritize disadvantaged groups directly, 2) to define priority groups in phased systems, 3) to plan tailored outreach and communication, 4) to plan the location of dispensing sites and 5) to monitor uptake. Yet just over a third of all states, and only half of the 16 states with the largest shares of disadvantaged populations—where reducing inequity would be most urgent—pursue such goals. While allocation frameworks are still evolving, the plans we analyzed mark important historical and practical benchmarks, and could become firm policy when COVID-19 vaccines are authorized and delivered. Vaccine roll-out poses unprecedented logistical and practical challenges. To minimize the risk that ethics and social justice falls by the wayside in the busy months to come, planners at the federal, state and local levels should carefully consider on what grounds they decline to adopt equity measures that other planners deem important and feasible for defining priority populations, designing allocation quotas, and just as critical, enabling, and monitoring, uptake

    Characteristics of EGRET Blazars in the VLBA Imaging and Polarimetry Survey (VIPS)

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    We examine the radio properties of EGRET-detected blazars observed as part of the VLBA Imaging and Polarimetry Survey (VIPS). VIPS has a flux limit roughly an order of magnitude below the MOJAVE survey and most other samples that have been used to study the properties of EGRET blazars. At lower flux levels, radio flux density does not directly correlate with gamma-ray flux density. We do find that the EGRET-detected blazars tend to have higher brightness temperatures, greater core fractions, and possibly larger than average jet opening angles. A weak correlation is also found with jet length and with polarization. All of the well-established trends can be explained by systematically larger Doppler factors in the gamma-ray loud blazars, consistent with the measurements of higher apparent velocities found in monitoring programs carried out at radio frequencies above 10 GHz.Comment: 20 pages, 7 figures, accepted to Ap

    Depression rating scales in Parkinson's disease: critique and recommendations.

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    Depression is a common comorbid condition in Parkinson’s disease (PD) and a major contributor to poor quality of life and disability. However, depression can be difficult to assess in patients with PD due to overlapping symptoms and difficulties in the assessment of depression in cognitively impaired patients. As several rating scales have been used to assess depression in PD (dPD), the Movement Disorder Society commissioned a task force to assess their clinimetric properties and make clinical recommendations regarding their use. A systematic literature review was conducted to explore the use of depression scales in PD and determine which scales should be selected for this review. The scales reviewed were the Beck Depression Inventory (BDI), Hamilton Depression Scale (Ham-D), Hospital Anxiety and Depression Scale (HADS), Zung Self-Rating Depression Scale (SDS), Geriatric Depression Scale (GDS), Montgomery-As-berg Depression Rating Scale (MADRS), Unified Parkinson’s Disease Rating Scale (UPDRS) Part I, Cornell Scale for the Assessment of Depression in Dementia (CSDD), and the Center for Epidemiologic Studies Depression Scale (CES-D). Seven clinical researchers with clinical and research experience in the assessment of dPD were assigned to review the scales using a structured format. The most appropriate scale is dependent on the clinical or research goal. However, observer-rated scales are preferred if the study or clinical situation permits. For screening purposes, the HAM-D, BDI, HADS, MADRS, and GDS are valid in dPD. The CES-D and CSDD are alternative instruments that need validation in dPD. For measurement of severity of depressive symptoms, the Ham-D, MADRS, BDI, and SDS scales are recommended. Further studies are needed to validate the CSDD, which could be particularly useful for the assessment of severity of dPD in patients with comorbid dementia. To account for overlapping motor and nonmotor symptoms of depression, adjusted instrument cutoff scores may be needed for dPD, and scales to assess severity of motor symptoms (e.g., UPDRS) should also be included to help adjust for confounding factors. The HADS and the GDS include limited motor symptom assessment and may, therefore, be most useful in rating depression severity across a range of PD severity; however, these scales appear insensitive in severe depression. The complex and time-consuming task of developing a new scale to measure depression specifically for patients with PD is currently not warranted

    The Grizzly, November 18, 1988

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    Booze Ban - No Bomb - But No New Booze News • Hess Awarded Honorary Chair • Talent Show Dazzles Ursinus Community • Letters: Alumnus Voices Drug Concerns; Stuff it in Your Socks, Mr. Bill • Escape with Chiapparone • Meehan, U.C. Spoil Dickinson\u27s Party • Pack Takes 3rd; O\u27Donohue Makes Nationals • Matters Fare Well at LaSalle Tourney • Circle Up with Circle K • Hoopsters Open with Cautious Optimismhttps://digitalcommons.ursinus.edu/grizzlynews/1224/thumbnail.jp

    The high-pressure phase of boron, {\gamma}-B28: disputes and conclusions of 5 years after discovery

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    {\gamma}-B28 is a recently established high-pressure phase of boron. Its structure consists of icosahedral B12 clusters and B2 dumbbells in a NaCl-type arrangement (B2){\delta}+(B12){\delta}- and displays a significant charge transfer {\delta}~0.5- 0.6. The discovery of this phase proved essential for the understanding and construction of the phase diagram of boron. {\gamma}-B28 was first experimentally obtained as a pure boron allotrope in early 2004 and its structure was discovered in 2006. This paper reviews recent results and in particular deals with the contentious issues related to the equation of state, hardness, putative isostructural phase transformation at ~40 GPa, and debates on the nature of chemical bonding in this phase. Our analysis confirms that (a) calculations based on density functional theory give an accurate description of its equation of state, (b) the reported isostructural phase transformation in {\gamma}-B28 is an artifact rather than a fact, (c) the best estimate of hardness of this phase is 50 GPa, (d) chemical bonding in this phase has a significant degree of ionicity. Apart from presenting an overview of previous results within a consistent view grounded in experiment, thermodynamics and quantum mechanics, we present new results on Bader charges in {\gamma}-B28 using different levels of quantum-mechanical theory (GGA, exact exchange, and HSE06 hybrid functional), and show that the earlier conclusion about significant degree of partial ionicity in this phase is very robust
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