19,291 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

    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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