23,520 research outputs found

    False discovery rate regression: an application to neural synchrony detection in primary visual cortex

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    Many approaches for multiple testing begin with the assumption that all tests in a given study should be combined into a global false-discovery-rate analysis. But this may be inappropriate for many of today's large-scale screening problems, where auxiliary information about each test is often available, and where a combined analysis can lead to poorly calibrated error rates within different subsets of the experiment. To address this issue, we introduce an approach called false-discovery-rate regression that directly uses this auxiliary information to inform the outcome of each test. The method can be motivated by a two-groups model in which covariates are allowed to influence the local false discovery rate, or equivalently, the posterior probability that a given observation is a signal. This poses many subtle issues at the interface between inference and computation, and we investigate several variations of the overall approach. Simulation evidence suggests that: (1) when covariate effects are present, FDR regression improves power for a fixed false-discovery rate; and (2) when covariate effects are absent, the method is robust, in the sense that it does not lead to inflated error rates. We apply the method to neural recordings from primary visual cortex. The goal is to detect pairs of neurons that exhibit fine-time-scale interactions, in the sense that they fire together more often than expected due to chance. Our method detects roughly 50% more synchronous pairs versus a standard FDR-controlling analysis. The companion R package FDRreg implements all methods described in the paper

    Detouring the Tax Reform Act of 1976: Tax Shelter Proprietorships

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    After briefly reviewing the so-called abusive aspects of tax shelters which led Congress to enact the Tax Reform Act of 1976, the authors focus on an unintended loophole-the tax shelter proprietorship. The tax shelter proprietorship remains a viable method of reducing federal income taxes payable by high bracket taxpayers. The business mechanics and tax aspects of a sound recording proprietorship are analyzed and specific suggestions for future reforms to deal with the problem of tax shelter proprietorships are delineated

    ADULT NEST ATTENDANCE AND DIET OF NESTLING RESPLENDENT QUETZALS (PHAROMACHRUS MOCINNO) IN THE TALAMANCA MOUNTAINS OF SOUTHERN COSTA RICA

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    Abstract ∙ Resplendent Quetzals (Pharomachrus mocinno) inhabit mid to high elevation forests from southern Mexico to Panama. Lipid rich fruits from the Lauraceae family have been found to account for a large proportion of adult diet across their annual life cycle. To better understand the relationship between quetzals and Lauraceae during the breeding season, we studied food deliveries to nestlings in the Talamanca Mountains at San Gerardo de Dota, Costa Rica in the Rio Savegre watershed. Our study had four primary objectives: 1) determine parental contribution of males and females feeding nestling quetzals, 2) determine type of food delivered to nestling quetzals, 3) determine if deliveries of fruit items were related to their abundance and/or nutritional content and 4) determine if Lauraceae fruits made up a large proportion of nestling diets based on the high preference quetzals have displayed for fruits from this plant family. Hourly delivery rates were similar for the male and female (1.24 ± 0.68 and 1.44 ± 0.84). During the first 6 days, the largest proportion of the diet was animal prey; primarily lizards and beetles. After day 6, fruit rapidly became the dominant food item delivered to nestlings until fledging. The dominant number of fruits delivered to nestling quetzals were fruits from the Lauraceae family and included Ocotea holdrigeiana, Necatandra cufodontisii, and Aiouea costaricensis. All three had some of the highest protein and lipid content of all fruits delivered to nestlings. O. holdrigeiana had the highest protein and lipid content of all fruits delivered, had the lowest relative abundance, and was delivered more frequently than all other fruits. Conservation strategies for this species should take into account not just increasing available habitat, but also increasing habitat quality by focusing on species composition to provide abundant food plants for the Resplendent Quetzal to forage.Resumen ∙ Atención al nido y dieta de pichones del Quetzal Resplandeciente (Pharomachrus mocinno) en las Montañas Talamanca del sur de Costa Rica El Quetzal Resplandeciente (Pharomachrus mocinno) habita bosques de media a alta elevación del sur de México a Panamá. Frutas ricas en lípidos de la familia Lauraceae han sido consideradas constituyentes importantes de su dieta a lo largo de su ciclo anual de vida. Para entender mejor la relación entre quetzales y Lauraceae durante la temporada de cría, estudiamos entregas alimenticias a pichones en las montañas Talamanca en San Gerardo de Dota, Costa Rica en la Cuenca del Rio Savegre. Nuestro estudio tuvo cuatro objetivos primarios: 1) determinar la contribución del macho y la hembra en la alimentación de crías de quetzal, 2) determinar el tipo de entregas alimenticias a crías de quetzal, 3) determinar si las entregas de artículos frutales fueron relacionadas a su abundancia y/o contenido nutricional, y 4) determinar si frutas de Lauraceae conformaron una gran proporción de la dieta de crías de quetzal basado en la alta preferencia que quetzales han demostrado por frutas de esta familia. La proporción de entregas por hora fue similar en machos y hembras (1.24 ± 0.68 y 1.44 ± 0.84). Durante los primeros 6 días, presa animales constituyeron la mayor proporción de la dieta, ante todo lagartijas y escarabajos. Después del día 6, frutos constituyeron rápidamente el artículo de dieta dominante entregado a crías hasta que estas dejaron el nido. La mayor cantidad de frutas entregadas a crías de quetzal perteneció a la familia Lauraceae incluyendo Ocotea holdrigeiana, Nectandra cufodontisii, y Aiouea costaricensis. Las tres tuvieron el más alto contenido lipídico y de proteína de todas las frutas entregadas a crías. Interesantemente, O. holdrigeiana tuvo el más alto contenido lípido y de proteína de todas las frutas entregadas, la más baja abundancia relativa en el ambiente circundante, y fue utilizada más frecuentemente que todas las otras frutas. Estrategias de conservación para esta especie deben tomar en cuenta no solo incrementar el hábitat disponible, pero también incrementar la calidad del hábitat enfocándose en la composición de las especies vegetales, para asegurarse de proveer frutos en abundancia para la alimentación del Quetzal Resplandeciente

    Overpumping Leads to California Groundwater Arsenic Threat

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    Water resources are being challenged to meet domestic, agricultural, and industrial needs. To complement finite surface water supplies that are being stressed by changes in precipitation and increased demand, groundwater is increasingly being used. Sustaining groundwater use requires considering both water quantity and quality. A unique challenge for groundwater use, as compared with surface water, is the presence of naturally occurring contaminants within aquifer sediments, which can enter the water supply. Here we find that recent groundwater pumping, observed through land subsidence, results in an increase in aquifer arsenic concentrations in the San Joaquin Valley of California. By comparison, historic groundwater pumping shows no link to current groundwater arsenic concentrations. Our results support the premise that arsenic can reside within pore water of clay strata within aquifers and is released due to overpumping. We provide a quantitative model for using subsidence as an indicator of arsenic concentrations correlated with groundwater pumping

    Acute red eye and back pain as a presentation for systemic illness: case report

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    BACKGROUND: Acute red eye is a common presentation in both primary and secondary care. Presentation in combination with other systemic symptoms can indicate serious underlying pathology. CASE PRESENTATION: 73-year-old lady presenting with endogenous endophthalmitis and thoracic discitis secondary to sub-acute bacterial endocarditis. CONCLUSION: Acute red eye in combination with systemic symptoms requires immediate investigation. If endogenous endophthalmitis is diagnosed, a source of sepsis should be comprehensively investigated and referral made to individual specialities if necessary

    The Effectiveness of the Critical Power Model on Prescribing Elements of Intermittent Exercise

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    Intermittent exercise is a valuable method of training, consisting of numerous interrelated factors. The critical power model has been used to administer interval training programs; however, it has not been used to accurately prescribe elements of intermittent exercise. PURPOSE: This study aimed to use individual critical power models to prescribe elements of intermittent exercise. METHODS: Ten male athletes, mean (sd) age and mass 19.6 (1.4) years and 77.8 (8.1) kg performed three phases of testing on a cycle ergometer: 1) familiarization, one learning trial to establish a starting point for subsequent tests; 2) establishment of individual W/t relationship from [Eq 1], i.e. t = W’ / (W – WCP), 4 bouts of exercise designed to elicit fatigue in 2-15 minutes; 3) intermittent exercise, 3 bouts of work with predicted number of work/recovery cycles (n = 5) of 60/60 s, 120/60 s, and 60/120 s. The elements of these bouts were prescribed using [Eq 2], i.e. n = W’ / ((Ww – WCP)tw – (WCP – Wr)tr) and estimates of W’ and CP from phase 2 of testing. One sample t-tests were used to compare the number of cycles actually completed to the predicted value of 5 cycles for each intermittent exercise bout. A repeated-measures ANOVA was used to compare the effect of intermittent exercise on the number of work/recovery cycles completed across conditions. RESULTS: The mean (sd) completed work/recovery cycles were 4.64 (0.47), 4.65 (1.10), and 3.70 (0.80), for the 60/60 s, 120/60 s, and 60/120 s trials, respectively. Results of the t-tests suggested that actual values were not significantly different from predicted for 60/60 s and 120/60 s (t(9) = -2.39, p = 0.04; t(9) = -1.01, p = 0.34), but were for 60/120 s (t(9) = -5.14, p \u3c 0.01). Results of the rANOVA suggested that the mean completed work/recovery cycles was significantly different across conditions (F(2,18) = 3.99, p = 0.04). DISCUSSION: These data suggest that using [Eq 2], with estimates of W’ and CP from [Eq 1], to prescribe elements of intermittent exercise can be successful for trials with short recovery periods

    The Effect of Cardiovascular Drift on the Efficacy of Exercise Prescription

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    TACSM Abstract – The Effect of Cardiovascular Drift on the Efficacy of Exercise Prescription KATHERINE FORESTER, JIMMY SMITH, Ph.D., and SCOTT MCLEAN, Ph.D. Kinesiology; Southwestern University; Georgetown, TX Category: Undergraduate ABSTRACT Due to the difficulty in measuring metabolic cost in the field, heart rate (HR) is often used to prescribe exercise intensity. Purpose: To examine the effect of cardiovascular drift (CVdrift) on the efficacy of exercise prescription (ExRx). Methods: Eight women with a mean (sd) age 21.6(2.0) years, body mass 70.9(11.0) kg, height 163.7(6.0) cm, and VO2max of 33.7(4.2) mL/kg/min, each performed two cycling trials for 30 to 45min at work rates that elicited 50% and 70% of VO2max. HR (bpm) and VO2 (mL/kg/min) were recorded throughout each trial and values at the beginning, middle, and end of exercise across both intensities were compared using 3 x 2 two-way repeated measures ANOVAs. Repeated measures ANOVAs were used to compare responses across time within each exercise intensity. Results: Estimated work rates accurately elicited 50% and 70% of HRmax and VO2max at 5 min of exercise. For HR, there was a significant effect of both time (F (1,2) = 124.8, p \u3c .001) and intensity (F (1,1) = 312.0, p \u3c .001), and a significant interaction between time and intensity (F (1,2) = 6.14, p = 0.012). There was a significant effect of time on HR at both the 50% intensity (F (1,2) = 40.74, p \u3c .001) and 70% intensity (F(1,2) = 101.9, p \u3c .001). VO2 increased significantly due to both time (F (1,2) = 6.63, p = .009) and intensity (F (1,1) = 312.0, p \u3c .001) but there was no interaction, and the significant effect of time was only at the 70% intensity (F (1,2) = 3.90, p = .05). Discussion: The main finding of this study was that HR and metabolic demand became increasingly dissociated across time at both intensities. This dissociation was more pronounced at an intensity of 70% of VO2max than 50% of VO2max. This finding implies that during prolonged exercise at a steady work rate, HR becomes increasingly less valid as a surrogate for metabolic demand of exercise. Key words: Cardiovascular drift, exercise prescription, metabolic drift

    Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 1: Executive summary

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    Primary results are summarized for a three-part study involving the effects of connecting a MOD-OA wind turbine generator to an isolated diesel power system. The MOD-OA installation considered was the third of four experimental nominal 200 kW wind turbines connected to various utilities under the Federal Wind Energy Program and was characterized by the highest wind energy penetration levels of four sites. The study analyses address: fuel displacement, dynamic interaction, and three modes of reactive power control. These analyses all have as their basis the results of the data acquisition program conducted on Block Island, Rhode Island

    Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 2: Data analysis

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    Assessing the performance of a MOD-OA horizontal axis wind turbine connected to an isolated diesel utility, a comprehensive data measurement program was conducted on the Block Island Power Company installation on Block Island, Rhode Island. The detailed results of that program focusing on three principal areas of (1) fuel displacement (savings), (2) dynamic interaction between the diesel utility and the wind turbine, (3) effects of three models of wind turbine reactive power control are presented. The approximate two month duration of the data acquisition program conducted in the winter months (February into April 1982) revealed performance during periods of highest wind energy penetration and hence severity of operation. Even under such conditions fuel savings were significant resulting in a fuel reduction of 6.7% while the MOD-OA was generating 10.7% of the total electrical energy. Also, electrical disturbance and interactive effects were of an acceptable level
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