2,322 research outputs found
Harvester-Forwarder and Harvester-Yarder Systems for Fuel Reduction Treatments
Two harvesting systems were compared for reducing fuel loadings in overstocked conifer stands in eastern Oregon; forest managers also set a high priority on minimizing soil disturbance. Both employed cut-to-length (CTL) harvesters; one used a forwarder and the other a small skyline yarder. Both systems produced very similar and acceptable results in terms of fuels reduction and soil disturbance, but at different stump-to-mill costs: 80/green ton for the yarder system
CO21 234. Implantación trans apical de válvula aórtica: excelentes resultados en pacientes de alto riesgo
ObjetivosLa implantación transapical de válvulas aórticas es un método nuevo aplicable a pacientes de alto riesgo y estenosis grave de válvula aórtica. Un informe de nuestra experiencia inicial.MétodosDesde abril de 2008 fueron tratados 208 pacientes (edad 79±8 anos, media 36-99 años), con el método híbrido de implantación transapical de válvula aórtica. La media logística EuroSCORE (STS) fue de 40±20% (6-97%) y la media del STS score 21±16% (3-97%). Catorce pacientes ingresaron en shock cardiogénico. Operaciones combinadas fueron efectuadas en 30 pacientes. Intervención de coronarias con stent en 25 pacientes, corrección de ASD en un paciente, dilatación de estenosis pulmonar en un paciente. Aneurismectomía en dos pacientes.Implantación de stent en la arteria renal en un paciente.ResultadosEl éxito técnico de las operaciones fue del 99,5%, la mortalidad hospitalaria fue de 5,7% para todo el grupo, 21% para el grupo en shock cardiogénico. No hubo complicaciones neurológicas en ningún paciente. En el 6% de los pacientes operados hubo la necesidad de implantación de marcapasos. El análisis de regresión univariante demuestra que el shock cardiogénico, elevado B-type natriuretic peptide (BNP)-level, son claros indicadores para la mortalidad postoperatoria temprana (30 días después de la operación). Shock cardiogénico, New York Heart Association (NYHA) IV, altos scores de riesgo, insuficiencia renal grave, son factores independientes para la predicción de la mortalidad acumulativa.ConclusionesLa técnica de recambio transapical de válvulas aórticas reduce significativamente el riesgo operatorio en pacientes de alto riesgo en comparación con el método convencional de recambio valvular aórtico
Do measures matter? Comparing surface-density-derived and census-tract-derived measures of racial residential segregation
<p>Abstract</p> <p>Background</p> <p>Racial residential segregation is hypothesized to affect population health by systematically patterning health-relevant exposures and opportunities according to individuals' race or income. Growing interest into the association between residential segregation and health disparities demands more rigorous appraisal of commonly used measures of segregation. Most current studies rely on census tracts as approximations of the local residential environment when calculating segregation indices of either neighborhoods or metropolitan areas. Because census tracts are arbitrary in size and shape, reliance on this geographic scale limits understanding of place-health associations. More flexible, explicitly spatial derivations of traditional segregation indices have been proposed but have not been compared with tract-derived measures in the context of health disparities studies common to social epidemiology, health demography, or medical geography. We compared segregation measured with tract-derived as well as GIS surface-density-derived indices. Measures were compared by region and population size, and segregation measures were linked to birth record to estimate the difference in association between segregation and very preterm birth. Separate analyses focus on metropolitan segregation and on neighborhood segregation.</p> <p>Results</p> <p>Across 231 metropolitan areas, tract-derived and surface-density-derived segregation measures are highly correlated. However overall correlation obscures important differences by region and metropolitan size. In general the discrepancy between measure types is greatest for small metropolitan areas, declining with increasing population size. Discrepancies in measures are greatest in the South, and smallest in Western metropolitan areas. Choice of segregation index changed the magnitude of the measured association between segregation and very preterm birth. For example among black women, the risk ratio for very preterm birth in metropolitan areas changed from 2.12 to 1.68 for the effect of high versus low segregation when using surface-density-derived versus tract-derived segregation indices. Variation in effect size was smaller but still present in analyses of neighborhood racial composition and very preterm birth in Atlanta neighborhoods.</p> <p>Conclusion</p> <p>Census tract-derived measures of segregation are highly correlated with recently introduced spatial segregation measures, but the residual differences among measures are not uniform for all areas. Use of surface-density-derived measures provides researchers with tools to further explore the spatial relationships between segregation and health disparities.</p
REMOVED: Process Intensification Through Micellar Enhanced Ultrafiltration
This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)
Evaluation of a Graphical Anesthesia Drug Display for Space Travel
As the frequency and duration of space travel increase, the potential need for emergency medical care in space grows, and with it the need for patient monitoring devices supporting therapeutic treatment. Providing emergency care to an injured astronaut may necessitate immediate surgery. During such events, the timely administration of anesthetic agents will need to be performed by someone who is not a formally trained anesthesiologist. The availability of usable real-time displays of intravenous anesthetic concentrations and effects could significantly enhance intraoperative clinical decision-making both in space and on earth. The effectiveness of the real-time anesthesia display on the management of total intravenous anesthesia was determined by 31 anesthesiologists participating in a simulation study. In the presence of the anesthesia drug display, clinicians maintained physiologic indicators such as blood pressure and heart rate closer to baseline levels. Participants also reported an increase in perceived performance when using the drug display. The results indicate that surgeries on earth and in orbit would benefit from the implementation of this display
Evaluating Medical Devices Remotely: Current Methods and Potential Innovations
Objective: We present examples of laboratory and remote studies, with a focus on studies appropriate for medical device design and evaluation. From this review and description of extant options for remote testing, we provide methods and tools to achieve research goals remotely. Background: The FDA mandates human factors evaluation of medical devices. Studies show similarities and differences in results collected in laboratories compared to data collected remotely in non-laboratory settings. Remote studies show promise, though many of these are behavioral studies related to cognitive or experimental psychology. Remote usability studies are rare but increasing, as technologies allow for synchronous and asynchronous data collection. Method: We reviewed methods of remote evaluation of medical devices, from testing labels and instruction to usability testing and simulated use. Each method was coded for the attributes (e.g., supported media) that need consideration in usability studies. Results: We present examples of how published usability studies of medical devices could be moved to remote data collection. We also present novel systems for creating such tests, such as the use of 3D printed or virtual prototypes. Finally, we advise on targeted participant recruitment. Conclusion: Remote testing will bring opportunities and challenges to the field of medical device testing. Current methods are adequate for most purposes, excepting the validation of Class III devices. Application: The tools we provide enable the remote evaluation of medical devices. Evaluations have specific research goals, and our framework of attributes helps to select or combine tools for valid testing of medical devices
Iso-osmotic regulation of nitrate accumulation in lettuce (Lactuca sativa L.)
Concerns about possible health hazards arising from human consumption of lettuce and other edible vegetable crops with high concentrations of nitrate have generated demands for a greater understanding of processes involved in its uptake and accumulation in order to devise more sustainable strategies for its control. This paper evaluates a proposed iso-osmotic mechanism for the regulation of nitrate accumulation in lettuce (Lactuca sativa L.) heads. This mechanism assumes that changes in the concentrations of nitrate and all other endogenous osmotica (including anions, cations and neutral solutes) are continually adjusted in tandem to minimise differences in osmotic potential of the shoot sap during growth, with these changes occurring independently of any variations in external water potential. The hypothesis was tested using data from six new experiments, each with a single unique treatment comprising a separate combination of light intensity, N source (nitrate with or without ammonium) and nitrate concentration carried out hydroponically in a glasshouse using a butterhead lettuce variety. Repeat measurements of plant weights and estimates of all of the main soluble constituents (nitrate, potassium, calcium, magnesium, organic anions, chloride, phosphate, sulphate and soluble carbohydrates) in the shoot sap were made at intervals from about 2 weeks after transplanting until commercial maturity, and the data used to calculate changes in average osmotic potential in the shoot. Results showed that nitrate concentrations in the sap increased when average light levels were reduced by between 30 and 49 % and (to a lesser extent) when nitrate was supplied at a supra-optimal concentration, and declined with partial replacement of nitrate by ammonium in the external nutrient supply. The associated changes in the proportions of other endogenous osmotica, in combination with the adjustment of shoot water content, maintained the total solute concentrations in shoot sap approximately constant and minimised differences in osmotic potential between treatments at each sampling date. There was, however, a gradual increase in osmotic potential (ie a decline in total solute concentration) over time largely caused by increases in shoot water content associated with the physiological and morphological development of the plants. Regression analysis using normalised data (to correct for these time trends) showed that the results were consistent with a 1:1 exchange between the concentrations of nitrate and the sum of all other endogenous osmotica throughout growth, providing evidence that an iso-osmotic mechanism (incorporating both concentration and volume regulation) was involved in controlling nitrate concentrations in the shoot
Long-term Effect of Intraocular Lens vs Contact Lens Correction on Visual Acuity after Cataract Surgery during Infancy: A Randomized Clinical Trial
© 2020 American Medical Association. All rights reserved. Importance: Although intraocular lenses (IOLs) are often implanted in children, little is known whether primary IOL implantation or aphakia and contact lens correction results in better long-term visual outcomes after unilateral cataract surgery during infancy. Objective: To compare long-term visual outcomes with contact lens vs IOL correction following unilateral cataract surgery during infancy. Design, Setting, and Participants: This multicenter randomized clinical trial enrolled 114 infants with a unilateral congenital cataract who underwent cataract surgery with or without primary IOL implantation between 1 and 6 months of age. Data on long-term visual outcomes were collected when the children were age 10.5 years (July 14, 2015, to July 12, 2019) and analyzed from March 30 through August 6, 2019. Interventions: Intraocular lens implantation at the time of cataract surgery. Main Outcomes and Measures: Best-corrected visual acuity using the electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) testing protocol. Analysis was performed on an intention-to-treat basis. Results: Best-corrected visual acuity was measured at age 10.5 years for 110 of the 114 patients (96%) enrolled as infants. The participants included 58 girls (53%) and 52 boys (47%). Overall, 27 of the children (25%) had good (logMAR 0.30 [Snellen equivalent, 20/40] or better) visual acuity in the treated eye (12 [22%] in the IOL group and 15 [27%] in the aphakia group), but 50 children (44%) had a visual acuity of logMAR 1.00 (Snellen equivalent, 20/200) or worse (25 [44%] in the IOL group and 25 [44%] in the aphakia group). The median logMAR acuity in the treated eye was similar in children randomized to receive an IOL at the time of cataract extraction (0.89; interquartile range [IQR], 0.33-1.43 [Snellen equivalent, 20/159]) and those who remained aphakic (0.86; IQR, 0.30-1.46 [Snellen equivalent, 20/145]) (IQR, 0.30-1.46; P =.82). Although the overall difference in median visual acuity between the 2 groups was small, the estimate was imprecise (99% CI for the difference in medians was-0.54 to 0.47). Conclusions and Relevance: As in previous phases of the study, visual acuity outcomes were highly variable with only 27 children (25%) achieving excellent visual acuity in their treated eye and 50 children (44%) having poor vision in the treated eye. Implanting an IOL at the time of cataract extraction was neither beneficial nor detrimental to the visual outcome
Pulmonary Metaphor Design and Anesthesia Simulation Testing
Medical decision making is a crucial process to successfully treat a critical medical emergency. During an unexpected medical event, astronauts, like anesthesiologists, must react quickly in a complex environment. Tools, such as the pulmonary metaphor display, were created to aid the medical caregiver\u27s decision making process. The pulmonary metaphor display is designed to help the caregiver collect and integrate pulmonary data to provide a more accurate, quicker diagnosis and treatment. The following outline anesthesiology simulation study will provide the data to prove that the pulmonary metaphor display is beneficial to medical decision making
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