469 research outputs found

    PESTICIDE TAX, CROPPING PATTERNS, AND WATER QUALITY IN SOUTH CENTRAL TEXAS

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    The impact of an ad valorem pesticide tax on cropping patterns and pesticide use was examined in the South Central Texas Crop Reporting District. Output supply equations were econometrically estimated and used in the simulation. A 25 percent tax on pesticide was estimated to have major impacts on cropping patterns and on pesticide use. Assuming other input and output prices were unaffected, the supply of one important crop would fall by more than half. Demand for some of the highly soluble and persistent pesticides, which present the greatest threat to groundwater quality, would also decrease substantially (some as much as 50 percent).Crops, Dual model, Pesticides, Water quality, Supply, Crop Production/Industries,

    Tarphonomus, a new genus of ovenbird (Aves: Passeriformes: Furnariidae) from South America

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    Tarphonomus, a new genus of ovenbird (Aves: Passeriformes: Furnariidae) from South America, is described. Species included in the new genus, formerly placed in Upucerthia, are T. certhioides and T. harterti

    Visual Recognition of Child Body Mass Index by Medical Students, Resident Physicians, and Community Physicians

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    Background: Many studies have assessed the ability of mothers to identify their child’s Body Mass Index (BMI) category and the vast majority of mothers are unable to do so accurately. This suggested a need for physicians to inform parents about their child’s weight status. However, many physicians do not chart BMI-for-age, even though it is recommended. Instead they rely on their visual perception of the patient’s weight status. This study determined the number of medical students, resident physicians, and community physicians who correctly categorize preschool children into their appropriate weight class by visual cues alone. Methods: Fourth-year medical students, family medicine and pediatric resident physicians, and family medicine and pediatric community physicians completed a brief on-line survey. Pictures of three preschool children were shown and respondents described each child’s BMI-for-age category. Results: A 43% (134/312) response rate was achieved. Only 15% of respondents correctly identified a 3-year-old boy, whose BMI was >95th percentile for his age, as obese. Nearly 86% correctly identified a 4-year-old girl with normal BMI-for-age, but only 21% correctly identified another girl who was overweight at the 90-95th percentile BMI-for-age. No significant difference was found in total accuracy between medical students, resident physicians, or community physicians (F(2,123)=0.743, p=0.478) or between family medicine physicians and pediatricians (F(1,107)=2.269, p=0.135) when predicting the BMI-for-age categories. Conclusions: Medical professionals and trainees have difficulty visually assessing a child’s BMI-for-age weight status. This underscores the importance of calculating and plotting BMI at healthy check-ups

    Assessing Physician Response Rate Using a Mixed-Mode Survey

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    Background. It is important to minimize time and cost of physician surveys while still achieving a reasonable response rate. Mixed-mode survey administration appears to improve response rates and decrease bias. A literature review revealed physician response rates to mixed-mode surveys averaged about 68%. However, no identified studies used the combination of e-mail, fax, and telephone. The purpose of this study was to evaluate physician response rates based on surveys first administered by e-mail, then fax, then telephone. Methods. Surveys initially were administered by e-mail to 149 physicians utilizing SurveyMonkey©. Two follow-up reminder e-mails were sent to non-respondents at two-week intervals. Surveys then were faxed to physicians who had not responded. A follow-up fax was sent to non-respondents one week later. Finally, phone interviews were attempted with physicians who had not responded by e-mail or fax; each physician was called at least twice. Results. Of the 149 eligible physicians, 102 completed the survey for a response rate of 68.5%. Of those who responded, 49 (48%) responded by e-mail, 25 (24.5%) by fax, and 28 (27.5%) by phone. Mode of response did not differ by gender, specialization, or years in practice. In addition, mode of response was not related to the primary study question, physician willingness to use text messaging for immunization reminders. Conclusions. This mix of survey methodologies appeared to be a feasible combination for achieving physician responses and may be more cost effective than other mixed methods

    Higher 30-day mortality associated with the use of intramedullary nails compared with sliding hip screws for the treatment of trochanteric hip fractures:a prospective national registry study

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    Aims The aim of this study was to investigate the association between the type of operation used to treat a trochanteric fracture of the hip and 30-day mortality. Patients and Methods Data on 82 990 patients from the National Hip Fracture Database were analyzed using generalized linear models with incremental case-mix adjustment for patient, non-surgical and surgical characteristics, and socioeconomic factors. Results The use of short and long intramedullary nails was associated with an increase in 30-day mortality (adjusted odds ratio (OR) 1.125, 95% confidence interval (CI) 1.040 to 1.218; p = 0.004) compared with the use of sliding hip screws (12.5% increase). If this were causative, it would represent 98 excess deaths over the four-year period of the study and one excess death would be caused by treating 112 patients with an intramedullary nail rather than a sliding hip screw. Conclusion There is a 12.5% increase in the risk of 30-day mortality associated with the use of an intramedullary nail compared with a sliding hip screw in the treatment of a trochanteric fractures of the hip.</p

    Phylogeny and phylogenetic classification of the antbirds, ovenbirds, woodcreepers, and allies (Aves: Passeriformes: Infraorder Furnariides)

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    The infraorder Furnariides is a diverse group of suboscine passerine birds comprising a substantial component of the Neotropical avifauna. The included species encompass a broad array of morphologies and behaviours, making them appealing for evolutionary studies, but the size of the group (ca. 600 species) has limited well-sampled higher-level phylogenetic studies. Using DNA sequence data from the nuclear RAG-1 and RAG-2 exons, we undertook a phylogenetic analysis of the Furnariides sampling 124 (more than 88%) of the genera. Basal relationships among family-level taxa differed depending on phylogenetic method, but all topologies had little nodal support, mirroring the results from earlier studies in which discerning relationships at the base of the radiation was also difficult. In contrast, branch support for family-rank taxa and for many relationships within those clades was generally high. Our results support the Melanopareidae and Grallariidae as distinct from the Rhinocryptidae and Formicariidae, respectively. Within the Furnariides our data contradict some recent phylogenetic hypotheses and suggest that further study is needed to resolve these discrepancies. Of the few genera represented by multiple species, several were not monophyletic, indicating that additional systematic work remains within furnariine families and must include dense taxon sampling. We use this study as a basis for proposing a new phylogenetic classification for the group and in the process erect new family-group names for clades having high branch support across methods. © 2009 The Willi Hennig Society

    Integrating Sequence Capture and Restriction Site-Associated DNA Sequencing to resolve Recent Radiations of Pelagic Seabirds

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    The diversification of modern birds has been shaped by a number of radiations. Rapid diversification events make reconstructing the evolutionary relationships among taxa challenging due to the convoluted effects of incomplete lineage sorting (ILS) and introgression. Phylogenomic datasets have the potential to detect patterns of phylogenetic incongruence, and to address their causes. However, the footprints of ILS and introgression on sequence data can vary between different phylogenomic markers at different phylogenetic scales depending on factors such as their evolutionary rates or their selection pressures. We show that combining phylogenomic markers that evolve at different rates, such as paired-end double-digest restriction site-associated DNA (PE-ddRAD) and ultraconserved elements (UCEs), allows a comprehensive exploration of the causes of phylogenetic discordance associated with short internodes at different timescales. We used thousands of UCE and PE-ddRAD markers to produce the first well-resolved phylogeny of shearwaters, a group of medium-sized pelagic seabirds that are among the most phylogenetically controversial and endangered bird groups. We found that phylogenomic conflict was mainly derived from high levels of ILS due to rapid speciation events. We also documented a case of introgression, despite the high philopatry of shearwaters to their breeding sites, which typically limits gene flow. We integrated state-of-the-art concatenated and coalescent-based approaches to expand on previous comparisons of UCE and RAD-Seq datasets for phylogenetics, divergence time estimation and inference of introgression, and we propose a strategy to optimise RAD-Seq data for phylogenetic analyses. Our results highlight the usefulness of combining phylogenomic markers evolving at different rates to understand the causes of phylogenetic discordance at different timescales

    Lineage diversification and morphological evolution in a large-scale continental radiation: The neotropical ovenbirds and woodcreepers (aves: furnariidae)

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    Patterns of diversification in species-rich clades provide insight into the processes that generate biological diversity. We tested different models of lineage and phenotypic diversification in an exceptional continental radiation, the ovenbird family Furnariidae, using the most complete species-level phylogenetic hypothesis produced to date for a major avian clade (97% of 293 species). We found that the Furnariidae exhibit nearly constant rates of lineage accumulation but show evidence of constrained morphological evolution. This pattern of sustained high rates of speciation despite limitations on phenotypic evolution contrasts with the results of most previous studies of evolutionary radiations, which have found a pattern of decelerating diversity-dependent lineage accumulation coupled with decelerating or constrained phenotypic evolution. Our results suggest that lineage accumulation in tropical continental radiations may not be as limited by ecological opportunities as in temperate or island radiations. More studies examining patterns of both lineage and phenotypic diversification are needed to understand the often complex tempo and mode of evolutionary radiations on continents. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution
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