43 research outputs found

    Does primary brachial plexus surgery alter palliative tendon transfer surgery outcomes in children with obstetric paralysis?

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    <p>Abstract</p> <p>Background</p> <p>The surgical management of obstetrical brachial plexus palsy can generally be divided into two groups; early reconstructions in which the plexus or affected nerves are addressed and late or palliative reconstructions in which the residual deformities are addressed. Tendon transfers are the mainstay of palliative surgery. Occasionally, surgeons are required to utilise already denervated and subsequently reinnervated muscles as motors. This study aimed to compare the outcomes of tendon transfers for residual shoulder dysfunction in patients who had undergone early nerve surgery to the outcomes in patients who had not.</p> <p>Methods</p> <p>A total of 91 patients with obstetric paralysis-related shoulder abduction and external rotation deficits who underwent a modified Hoffer transfer of the latissimus dorsi/teres major to the greater tubercle of the humerus tendon between 2002 and 2009 were retrospectively analysed. The patients who had undergone neural surgery during infancy were compared to those who had not in terms of their preoperative and postoperative shoulder abduction and external rotation active ranges of motion.</p> <p>Results</p> <p>In the early surgery groups, only the postoperative external rotation angles showed statistically significant differences (25 degrees and 75 degrees for total and upper type palsies, respectively). Within the palliative surgery-only groups, there were no significant differences between the preoperative and postoperative abduction and external rotation angles. The significant differences between the early surgery groups and the palliative surgery groups with total palsy during the preoperative period diminished postoperatively (p < 0.05 and p > 0.05, respectively) for abduction but not for external rotation. Within the upper type palsy groups, there were no significant differences between the preoperative and postoperative abduction and external rotation angles.</p> <p>Conclusions</p> <p>In this study, it was found that in patients with total paralysis, satisfactory shoulder abduction values can be achieved with tendon transfers regardless of a previous history of neural surgery even if the preoperative values differ.</p

    EUSO-SPB1 mission and science

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    The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of âȘ† 3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search

    EUSO-SPB2 Telescope Optics and Testing

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    The Extreme Universe Space Observatory - Super Pressure Balloon (EUSO-SPB2) mission will fly two custom telescopes that feature Schmidt optics to measure Cherenkov- and fluorescence emission of extensive air showers from cosmic rays at the PeV and EeV-scale, and search for τ-neutrinos. Both telescopes have 1-meter diameter apertures and UV/UV-visible sensitivity. The Cherenkov telescope uses a bifocal mirror segment alignment, to distinguish between a direct cosmic ray that hits the camera versus the Cherenkov light from outside the telescope. Telescope integration and laboratory calibration will be performed in Colorado. To estimate the point spread function and efficiency of the integrated telescopes, a test beam system that delivers a 1-meter diameter parallel beam of light is being fabricated. End-to-end tests of the fully integrated instruments will be carried out in a field campaign at dark sites in the Utah desert using cosmic rays, stars, and artificial light sources. Laser tracks have long been used to characterize the performance of fluorescence detectors in the field. For EUSO-SPB2 an improvement in the method that includes a correction for aerosol attenuation is anticipated by using a bi-dynamic Lidar configuration in which both the laser and the telescope are steerable. We plan to conduct these field tests in Fall 2021 and Spring 2022 to accommodate the scheduled launch of EUSO-SPB2 in 2023 from Wanaka, New Zealand

    Does prekindergarten experience influence children\u27s subsequent educational development? A study of kindergarten teachers\u27 perceptions and students\u27 performance

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    The purpose of this study was to examine the influence of different types of prekindergarten experience on kindergarten students\u27 educational readiness. Prior studies documented that prekindergarten programs can have positive effects on readiness for and early progress in school (Campbell and Ramey, 1994; Miller and Bizzell, 1983; Weikart, Bond and McNeil, 1978). While these studies made valuable contributions to our understanding of prekindergarten programs, their policy implications have been limited by their measures of readiness (norm-referenced tests or IQ scores unrelated to specific skills expected of children entering kindergarten, or teacher ratings unrelated to direct measures of student performance) and by their failure to distinguish between different types of preschool experiences. This study addresses these limitations by distinguishing between the influence of no, half-day, and full-day prekindergarten experience on children\u27s developmental growth and literacy development using a combination of criterion-referenced assessments of student performance and a survey of teachers\u27 perceptions. Educational readiness was measured both directly by measures of student performance and indirectly by kindergarten teachers\u27 reported perceptions. A random sample of 346 kindergarten students\u27 performance was measured by using two criterion-referenced assessments, assessing developmental level and literacy development, at the beginning and end of kindergarten. The sample was drawn from the population of all kindergarten students in the Syracuse City School District (a high-needs urban district in upstate New York) who previously attended a half-day or full-day New York State public school prekindergarten program or who had not attended any preschool program. Teacher perceptions were studied using The DeSiato Kindergarten Teacher Perception Student Readiness Survey, which was developed and administered to a random sample of 55 kindergarten teachers in the Syracuse District. The survey included 50 specific indicators of readiness widely discussed in the literature. This study provides strong evidence that students\u27 educational readiness, subsequent development and literacy are influenced by their type of prekindergarten experience. Students who attended half-day prekindergarten performed better than students with no prekindergarten and students who attended full-day prekindergarten outperformed students with either no or half-day prekindergarten. This study has significant implications for public policy, school district practice and research on prekindergarten programs

    Event horizons in the Polarizable Vacuum Model

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    The Polarizable Vacuum (PV) Model representation of General Relativity (GR) is used to show that an in-falling particle of matter will reach the central mass object in a finite amount of proper time, as measured along the world line of the particle, when using the PV Metric. It is shown that the in-falling particle passes through an event horizon, analogous to that found in the Schwarzschild solution of GR. Once it passes through this horizon, any light signal emitted outward by the in-falling particle will be moving slower than the in-falling particle, due to the reduced speed of light in this region. Therefore the signal can never escape this horizon. However, the light emitted by a stationary object below the horizon is exponentially red-shifted and can escape along the null geodesics, as was originally predicted by the PV Model. A static, non-rotating charge distribution is added to the central mass and the PV equivalent to the Reissner-Nordstrom metric is derived. It is illustrated that the dipole moment induced in a neutral, polarizable body, reduces the effects of gravity in the strong field region. We demonstrate the existence of the event horizon and how it may be affected by the presence of electric charge

    The Electromagnetic Zero-Point Field and the Flat Polarizable Vacuum Representation

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    There are several interpretations of the Polarizable Vacuum (PV). One is the variable speed of light (VSL) approach, that has been shown to be isomorphic to General Relativity (GR) within experimental limits. However, another interpretation is representative of flat geometry, in which intervals of time and distance are measured in local inertial reference frames where the speed of light remains constant. The Flat PV approach leads to variable impedance transformations, governed by the spectral energy content of the Quantum Vacuum’s Electromagnetic (EM) Zero-Point Field (ZPF). The EM ZPF consists of photons. An unlimited number of photons may occupy the same quantum state at an arbitrary set of coordinates. Therefore, the spectral energy of the ZPF may be varied smoothly, represented by a superposition of EM waves with a large number of photons per cubic wavelength. Utilizing the Flat PV representation, a family of frequency dependent solutions of Poisson’s equation are derived, that may be applied as tools for engineering the PV space-time metric, within the GR representation

    Measuring the cortical silent period can increase diagnostic confidence for amyotrophic lateral sclerosis.

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    Contains fulltext : 53464.pdf (publisher's version ) (Closed access)We evaluated a modified measurement of the cortical silent period (CSP) as a simple procedure to add further confidence in the diagnostic work-up for ALS. Thirty-seven consecutive patients with a suspicion of having ALS were included together with 25 healthy volunteers, and followed until a final diagnosis (ALS versus 'ALS mimic') was reached. Using a CSP cut-off value of 200 ms for males and 150 ms for females, the following test characteristics were obtained for ALS versus ALS mimics together with controls: sensitivity for excluding ALS 0.83, specificity 0.56 (males) and sensitivity 0.81, specificity 0.82 (females). A CSP longer than the mentioned cut-off values should alarm the clinician for the presence of a disorder other than ALS
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