2,606 research outputs found

    Delayed Repair of Myelomeningoceles

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    Objective: Myelomeningocele is a defect that is typically surgically repaired within the first few days of life in developed countries to minimize the risk of meningitis. If left unrepaired, these children may survive to have their meningocele sac epithelialize. The surgical reduction and closure of an epithelialized myelomeningocele represents a unique challenge for the neurosurgeon, as it requires a modification of the typical closure technique. Methods: 10 years experience in 97 patients with the delayed (\u3e6 months) repair of myelomeningoceles was the basis of this report. Results: Repair technique in a child with a myelomeningocele that was not repaired at birth presented a surgical challenge whose solutions are presented herein. Conclusion: Delayed closure of myelomeningoceles is facilitated by adherence to lessons learned form surgical experience on medical missions to Guatemala

    Multiyear defoliations in southern New England increases oak mortality

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    After decades of multiyear defoliation episodes in southern New England, Lymantria dispar dispar (LDD; previously gypsy moth) populations collapsed with the appearance of the LDD fungus in 1989. Multiyear defoliations did not occur again until 2015-2018. To assess the impact of the return of multiyear defoliations, we examined 3095 oaks on 29 permanent study areas in Connecticut and Rhode Island that were established at least eleven years before the latest outbreaks. Pre-defoliation stand level oak mortality averaged 2% (three-year basis). Post-defoliation mortality did not differ between managed and unmanaged stands, but was much higher in severely defoliated stands (36%) than in stands with moderate (7%) or low-no defoliation (1%). Pre-defoliation mortality of individual trees differed among species, was lower for larger diameter trees and on unmanaged than managed stands. Post-defoliation mortality on plots with no to moderate defoliation was similar to pre-defoliation mortality levels. Following multiyear defoliations, white oak mortality was higher than for northern red and black oak. There was weak evidence that mortality was elevated on stands with higher basal area following severe defoliation. Natural resource managers should not assume that oaks that survived earlier multiyear defoliations episodes will survive future multiyear outbreaks, possibly because trees are older

    Perceptual Centre correlates in Evoked Potentials

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    Perceptual centres (p-centres) are the subjective moments of occurrence of acoustic stimuli. When sounds are perceived in synchrony or are regularly spaced, it is their p-centres which occur synchronously or are isochronous. In order to analyse or model the acoustic features which influence the p-centre, it is necessary to measure p-centres for many stimuli. However there is a problem: it is difficult for an external observer to determine the exact time at which a listener perceives a sound’s occurrence. A possible solution is to find a measurable electrophysiological correlate of the p-centre. In order to investigate this, an experiment is described which compares features of the Auditory Evoked Potential (AEP) response and p-centres for a number of speech and synthetic stimuli. The results indicate a correlation between the latency of the dominant negative peak of the AEP and the p-centre

    Water Quality of Cayuga Lake 1991-1998

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    Cayuga and Seneca Lakes represent a major water resource of central New York State of considerable economic, recreational and aesthetic value. Maintenance of water quality, prevention of further deterioration of water quality and restoration of a lake’s health are major concerns of the public. Monitoring the water quality of Cayuga Lake has continued periodically from the early 1900\u27s to the present. This report reviews data collected by the Seneca County Soil and Water Conservation District during the 1991- 1998 period from the north end of Cayuga Lake. The water quality data presented are the result of a new strategy to continually monitor Cayuga Lake. Monitoring, as performed, provides the important function of documenting gradual improvements that may result from restoration efforts and remedial action plans. Similarly, monitoring provides evidence of deterioration of water quality and thus the opportunity for a management response and notification of the public of such changes. By considering nutrient and chlorophyll a concentrations and water clarity measurements, we review the current data from Cayuga Lake using the previous historical measurements of the lake

    Graphene formation on SiC substrates

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    Graphene layers were created on both C and Si faces of semi-insulating, on-axis, 4H- and 6H-SiC substrates. The process was performed under high vacuum (<10-4 mbar) in a commercial chemical vapor deposition SiC reactor. A method for H2 etching the on-axis sub-strates was developed to produce surface steps with heights of 0.5 nm on the Si-face and 1.0 to 1.5 nm on the C-face for each polytype. A process was developed to form graphene on the substrates immediately after H2 etching and Raman spectroscopy of these samples confirmed the formation of graphene. The morphology of the graphene is described. For both faces, the underlying substrate morphology was significantly modified during graphene formation; sur-face steps were up to 15 nm high and the uniform step morphology was sometimes lost. Mo-bilities and sheet carrier concentrations derived from Hall Effect measurements on large area (16 mm square) and small area (2 and 10 um square) samples are presented and shown to compare favorably to recent reports.Comment: European Conference on Silicon Carbide and Related Materials 2008 (ECSCRM '08), 4 pages, 4 figure

    The Exclusion of Restrictive Lung Disease by Spirometric Criteria in Patients with a Reduced Forced Vital Capacity

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    Reductions in forced vital capacity (EVC) as determined by spirometry may result from restrictive or obstructive disease, either alone or in combination. Restrictive disease is implied when measures of forced expiratory flow are relatively maintained, and obstructive disease is present when flow measurements are disproportionately reduced. In the presence of air flow obstruction, the possibility of concomitant restrictive disease contributing to the reduction in FVC is difficult to assess from spirometry alone. Static lung volumes are usually necessary to establish this diagnosis. We evaluated the FEV1/EVC%o obtained at spirometry compared to its predicted normal value. We found it to be useful in eliminating the need for additional testing in many cases in which the question of mixed obstructive and restrictive disease had been raised. Specifically, in patients with obstructive disease and a reduced FVC, an FEV1/FVC% of less than 81%, of the age-, height-, and sex-matched predicted value largely excluded the possibility that concomitant restrictive disease was also present (p\u3c.05). Higher values had no predictive value

    EPSTEIN-BARR VIRUS-NEGATIVE HUMAN MALIGNANT T-CELL LINES

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