1,849 research outputs found

    The 'Sphere': A Dedicated Bifurcation Aneurysm Flow-Diverter Device.

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    We present flow-based results from the early stage design cycle, based on computational modeling, of a prototype flow-diverter device, known as the 'Sphere', intended to treat bifurcation aneurysms of the cerebral vasculature. The device is available in a range of diameters and geometries and is constructed from a single loop of NITINOL(®) wire. The 'Sphere' reduces aneurysm inflow by means of a high-density, patterned, elliptical surface that partially occludes the aneurysm neck. The device is secured in the healthy parent vessel by two armatures in the shape of open loops, resulting in negligible disruption of parent or daughter vessel flow. The device is virtually deployed in six anatomically accurate bifurcation aneurysms: three located at the Basilar tip and three located at the terminus bifurcation of the Internal Carotid artery (at the meeting of the middle cerebral and anterior cerebral arteries). Both steady state and transient flow simulations reveal that the device presents with a range of aneurysm inflow reductions, with mean flow reductions falling in the range of 30.6-71.8% across the different geometries. A significant difference is noted between steady state and transient simulations in one geometry, where a zone of flow recirculation is not captured in the steady state simulation. Across all six aneurysms, the device reduces the WSS magnitude within the aneurysm sac, resulting in a hemodynamic environment closer to that of a healthy vessel. We conclude from extensive CFD analysis that the 'Sphere' device offers very significant levels of flow reduction in a number of anatomically accurate aneurysm sizes and locations, with many advantages compared to current clinical cylindrical flow-diverter designs. Analysis of the device's mechanical properties and deployability will follow in future publications

    Hot multiboundary wormholes from bipartite entanglement

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    We analyze the 1+1 CFT states dual to hot (time-symmetric) 2+1 multiboundary AdS wormholes. These are black hole geometries with high local temperature, n1n\geqslant 1 asymptotically-AdS3 regions, and arbitrary internal topology. The dual state at t = 0 is defined on n circles. We show these to be well-described by sewing together tensor networks corresponding to thermofield double states. As a result, the entanglement is spatially localized and bipartite: away from particular boundary points ('vertices') any small connected region A of the boundary CFT is entangled only with another small connected region B, where B may lie on a different circle or may be a different part of the same circle. We focus on the pair-of-pants case, from which more general cases may be constructed. We also discuss finite-temperature corrections, where we note that the states involve a code subspace in each circle

    Civil and forensic patients : comparing demographics, risk factors, and negative life events

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    OBJECTIVES: This investigation centres on how the mentally ill with a forensic admission compare to the mentally ill with a civil admission, and investigates who inpatients with a forensic and civil admission are, and how the risk factors and negative historical events they have experienced compare or differ. THEORETICAL BASE: Using a risk and resilience framework, risk factors that are deleterious to healthy development are used as variables. METHODS: The records of all adult inpatients both forensic and civil, aged 18 to 89 at admission in two U.S. mountain region public psychiatric hospitals were included in the sample (n=1768). All patients are assessed using the Colorado Clinical Assessment Record (CCAR) which, measures a diverse set of variables including Current Issues, History of Issues, Demographics, and Disabilities. OUTCOMES: Civil and forensic patients have more in common than differences. Both samples compare more closely to risk factors and negative historical events than they do to the general population. However, this begins to break down once the sample is separated by gender. SOCIAL WORK IMPLICATIONS: Social Workers who work in prison systems need to become more familiar with mental illness interventions. Additionally, social workers should both educate law enforcement about de-escalation tactics with the mentally ill and intervene on mental health related police calls. On the macro level, social workers should advocate for the mentally ill to be housed in psychiatric hospitals rather than be imprisoned where they will often not receive inpatient psychiatric care

    Bostonia. Volume 13

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    Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

    Проблеми становлення і розвитку інформаційного законодавства в контексті євроінтеграції України

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    Щодо розвитку права і правової науки в інформаційній сфері в Україні.О развитии права и правовой науки в информационной сфере в Украине.On the development of law and law science in the informative sphere of Ukraine

    The normal ranges of cardiovascular parameters measured using the ultrasonic cardiac output monitor

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    The ultrasonic cardiac output monitor (USCOM) is a noninvasive transcutaneous continuous wave Doppler method for assessing hemodynamics. There are no published reference ranges for normal values in adults (aged 18– 60 years) for this device. This study aimed to (1) measure cardiovascular indices using USCOM in healthy adults aged 18–60 years; (2) combine these data with those for healthy children (aged 0–12), adolescents (aged 12–18), and the elderly (aged over 60) from our previously published studies in order to present normal ranges for all ages, and (3) establish normal ranges of USCOM-derived variables according to both weight and age. This was a population- based cross-sectional observational study of healthy Chinese subjects aged 0.5–89 years in Hong Kong. USCOM scans were performed on all subjects, to produce measurements including stroke volume, cardiac output, and systemic vascular resistance. Data from previously published studies (children, adolescents, and the elderly) were included. Normal ranges were defined as lying between the 2.5th and 97.5th percentiles. A total of 2218 subjects were studied (mean age = 16.4, range = 0.5–89; 52% male). From previous studies, 1197 children (aged 0–12, 55% male), 590 adolescents (aged 12–18, 49% male), and 77 elderly (aged 60–89, 55% male) were included. New data were collected from 354 adults aged 18–60 (47% male). Normal ranges are presented according to age and weight. We present comprehensive normal ranges for hemodynamic parameters obtained with USCOM in healthy subjects of all ages from infancy to the elderly

    Spin-dipole induced lifetime of the least-bound quintet sigma state of He(2S)+He(2S)

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    The properties of the least-bound vibrational level (v=14) of the quintet sigma state formed during the ultracold collision of two spin-polarized metastable helium atoms are crucial to studies of photoassociation spectroscopy of metastable helium. We report a calculation of the autoionization lifetime of this state induced by spin-dipole coupling of the quintet sigma state to the singlet sigma state from which Penning and associative ionization processes are highly probable. We find a lifetime of about 150 microseconds, significantly larger than the recent experimental estimates of (4-5) microseconds.Comment: REVTEX4, four double-column page

    Charge Exchange Processes between Excited Helium and Fully Stripped Ions

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    We made a classical trajectory Monte Carlo (CTMC) calculation of state selective cross sections for processes between some light ions and excited helium. The results, useful for analysis of spectroscopic data of fusion devices, are in good agreement with theoretical predictions of scaling laws.Comment: LaTex, 8 pages, 4 figures (available on request to the authors), DFPD/94/TH/57, to be published in Phys. Rev.
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