199 research outputs found

    Sospechas y evidencia: revisión de las causas de la extinción local y del declive de los mejillones de agua dulce

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    Sospechas y evidencia: revisión de las causas de la extinción local y del declive de los mejillones de agua dulce La conservación de la biodiversidad requiere pruebas fiables de las causas de extinción local. Utilizando los mejillones de agua dulce como ejemplo, llevamos a cabo esta valoración sistemática, la primera que se ha realizado, de la evidencia de peligro para cualquier grupo de organismos. Revisamos artículos que publicaban conclusiones sobre las causas de las extinciones locales, evaluando la calidad de las pruebas según una escala objetiva. Encontramos que únicamente el 48% de los estudios presentaban relaciones plausibles entre la extinción local y sus causas. Los análisis carecían de resolución, dado que más del 75% de los estudios considerados (n = 124) sugerían múltiples causas de extinción local. Los estudios llevados a cabo en grandes áreas, y los que presentaban menos pruebas, son los que abogaban por un mayor número de causas. A pesar de las evidencias, que frecuentemente eran débiles, existía un acuerdo sustancial sobre la identidad de las causas; la más frecuente era la destrucción o alteración del hábitat, pero se postulaban muchas más. A pesar de que la extinción local de los mejillones de agua dulce es indudablemente una realidad, las pruebas podrían ser más consistentes. En estos animales y en muchos otros, la evidencia de las causas de su extinción local a menudo ha sido circunstancial. Presentamos aquí un estudio sistemático que pueden utilizar los ecólogos, para fortalecer las evidencias concernientes a las causas de las extinciones locales. También hemos reflejado la relación entre la fortaleza de la evidencia y las prioridades económicas de las investigaciones. Palabras clave: Evidencia, Extinción, Extinción local, Agua dulce, Mejillones.Conservation of biodiversity requires reliable evidence of the causes of extirpation. Using freshwater mussels as an example, we performed the first–ever systematic assessment of the evidence for endangerment of any group of organisms. We surveyed articles publishing conclusions about the cause of local extirpation by assessing the quality of evidence on an objective scale. We found that only 48% of studies presented plausible links between extirpation and causes. Analyses lacked resolution since more than 75% of all studies considered (n = 124) suggested multiple causes of extirpation. Studies performed over large areas and those presenting less evidence postulated the most causes. Despite the frequently weak evidence, there was substantial agreement on the identity of causes; the most frequent was habitat destruction or alteration but many others were postulated. Although mussel extirpation is undoubtedly real, the evidence could be stronger. In these animals and others, evidence of the causes of extirpation has often been circumstantial. We present a systematic approach ecologists can use to strengthen the evidence concerning the causes of extirpation. We also reflect on the link between the strength of evidence and research funding priorities. Key words: Evidence, Extinction, Extirpation, Freshwater, Mussels.La conservación de la biodiversidad requiere pruebas fiables de las causas de extinción local. Utilizando los mejillones de agua dulce como ejemplo, llevamos a cabo esta valoración sistemática, la primera que se ha realizado, de la evidencia de peligro para cualquier grupo de organismos. Revisamos artículos que publicaban conclusiones sobre las causas de las extinciones locales, evaluando la calidad de las pruebas según una escala objetiva. Encontramos que únicamente el 48% de los estudios presentaban relaciones plausibles entre la extinción local y sus causas. Los análisis carecían de resolución, dado que más del 75% de los estudios considerados (n = 124) sugerían múltiples causas de extinción local. Los estudios llevados a cabo en grandes áreas, y los que presentaban menos pruebas, son los que abogaban por un mayor número de causas. A pesar de las evidencias, que frecuentemente eran débiles, existía un acuerdo sustancial sobre la identidad de las causas; la más frecuente era la destrucción o alteración del hábitat, pero se postulaban muchas más. A pesar de que la extinción local de los mejillones de agua dulce es indudablemente una realidad, las pruebas podrían ser más consistentes. En estos animales y en muchos otros, la evidencia de las causas de su extinción local a menudo ha sido circunstancial. Presentamos aquí un estudio sistemático que pueden utilizar los ecólogos, para fortalecer las evidencias concernientes a las causas de las extinciones locales. También hemos reflejado la relación entre la fortaleza de la evidencia y las prioridades económicas de las investigaciones. Palabras clave: Evidencia, Extinción, Extinción local, Agua dulce, Mejillones

    Improved surveillance for early detection of a potential invasive species: the alien Rose-ringed parakeet Psittacula krameri in Australia

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    Published online: 12 November 2016The Rose-ringed parakeet Psittacula krameri is the most widely introduced parrot in the world, and is an important agricultural pest and competitor with native wildlife. In Australia, it is classified as an ‘extreme threat’, yet captive individuals frequently escape into the wild. The distribution and frequency of incursions are currently unknown, as are the potential impacts of the species in Australia. This lack of critical ecological information greatly limits effective biosecurity surveillance and decision-making efforts. We compiled a unique dataset, which combined passive surveillance sources from government and online resources, for all available information on parakeet detections at-large in Australia. We investigated whether geographic variables successfully predicted parakeet incursions, and used species distribution models to assess the potential distribution and economic impacts on agricultural assets. We recorded 864 incursions for the period 1999–2013; mostly escaped birds reported to missing animal websites. Escapes were reported most frequently within, or around, large cities. Incursions were best predicted by factors related to human presence and activity, such as global human footprint and intensive land uses. We recommend surveillance of high (predicted) establishment areas adjacent to cities where a feral parakeet population could most affect horticultural production. Novel passive surveillance datasets combined with species distribution models can be used to identify the regions where potential invasive species are most likely to establish. Subsequently, active surveillance can be targeted to the areas of highest predicted potential risk. We recommend an integrated approach that includes outreach programs involving local communities, as well as traditional biosecurity surveillance, for detecting new incursions.Miquel Vall-llosera, Andrew P. Woolnough, Dean Anderson, Phillip Casse

    A stepped wedge cluster randomized trial of graphical surveillance of kidney function data to reduce late presentation for kidney replacement therapy.

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    Late presentation for kidney replacement therapy (KRT) is an important cause of avoidable morbidity and mortality. Here, we evaluated the effect of a complex intervention of graphical estimated glomerular filtration rate (eGFR) surveillance across 15% of the United Kingdom population on the rate of late presentation using data routinely collected by the United Kingdom Renal Registry. A stepped wedge cluster randomized trial was established across 19 sites with eGFR graphs generated from all routine blood tests (community and hospital) across the population served by each site. Graphs were reviewed by trained laboratory or clinical staff and high-risk graphs reported to family doctors. Due to delays outside the control of clinicians and researchers few laboratories activated the intervention in their randomly assigned time period, so the trial was converted to a quasi-experimental design. We studied 6,100 kidney failure events at 20 laboratories served by 17 main kidney units. A total of 63,981 graphs were sent out. After adjustment for calendar time there was no significant reduction in the rate of presentation during the intervention period. Therefore, implementation of eGFR graph surveillance did not reduce the rate of late presentation for KRT after adjustment for secular trends. Thus, graphical surveillance is an intervention aimed at reducing late presentation, but more evidence is required before adoption of this strategy can be recommended. [Abstract copyright: Copyright © 2024. Published by Elsevier Inc.

    Evaluation of multi-season convection-permitting atmosphere – mixed-layer ocean simulations of the Maritime Continent

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    A multi-season convection-permitting regional climate simulation of the Maritime Continent (MC) using the Met Office Unified Model (MetUM) with 2.2 km grid spacing is presented and evaluated. The simulations pioneer the use of atmosphere–ocean coupling with the multi-column K profile parametrisation (KPP) mixed-layer ocean model in atmospheric convection-permitting climate simulations. Comparisons are made against a convection-parametrised simulation in which it is nested and which in turn derives boundary conditions from the ERA5 reanalysis. This paper describes the configuration, performance of the mean state and variability in the two simulations compared against observational datasets. The models have both minor sea surface temperature (SST) and wet precipitation biases. The diurnal cycle, representation of equatorial waves, and relationship between SST and precipitation are all improved in the convection-permitting model compared to the convection-parametrised model. The Madden–Julian oscillation (MJO) is present in both models with a faster-than-observed propagation speed. However, it is unclear whether fidelity of the MJO simulation is inherent to the model or whether it predominantly arises from the forcing at the boundaries.</p

    Virtual reality, ultrasound-guided liver biopsy simulator: Development and performance discrimination

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    Objectives: The aim of this article was to identify and prospectively investigate simulated ultrasound-guided targeted liver biopsy performance metrics as differentiators between levels of expertise in interventional radiology. Methods: Task analysis produced detailed procedural step documentation allowing identification of critical procedure steps and performance metrics for use in a virtual reality ultrasound-guided targeted liver biopsy procedure. Consultant (n=14; male=11, female=3) and trainee (n=26; male=19, female=7) scores on the performance metrics were compared. Ethical approval was granted by the Liverpool Research Ethics Committee (UK). Independent t-tests and analysis of variance (ANOVA) investigated differences between groups. Results: Independent t-tests revealed significant differences between trainees and consultants on three performance metrics: targeting, p=0.018, t=22.487 (22.040 to 20.207); probe usage time, p=0.040, t=2.132 (11.064 to 427.983); mean needle length in beam, p=0.029, t=22.272 (20.028 to 20.002). ANOVA reported significant differences across years of experience (0–1, 1–2, 3+ years) on seven performance metrics: no-go area touched, p=0.012; targeting, p=0.025; length of session, p=0.024; probe usage time, p=0.025; total needle distance moved, p=0.038; number of skin contacts, p<0.001; total time in no-go area, p=0.008. More experienced participants consistently received better performance scores on all 19 performance metrics. Conclusion: It is possible to measure and monitor performance using simulation, with performance metrics providing feedback on skill level and differentiating levels of expertise. However, a transfer of training study is required

    Validity and worth in the science curriculum: learning school science outside the laboratory

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    It is widely acknowledged that there are problems with school science in many developed countries of the world. Such problems manifest themselves in a progressive decline in pupil enthusiasm for school science across the secondary age range and the fact that fewer students are choosing to study the physical sciences at higher levels and as careers. Responses to these developments have included proposals to reform the curriculum, pedagogy and the nature of pupil discussion in science lessons. We support such changes but argue from a consideration of the aims of science education that secondary school science is too rooted in the science laboratory; substantially greater use needs to be made of out-of-school sites for the teaching of science. Such usage should result in a school science education that is more valid and more motivating and is better at fulfilling defensible aims of school science education. Our contention is that laboratory-based school science teaching needs to be complemented by out-of-school science learning that draws on the actual world (e.g. through fieldtrips), the presented world (e.g. in science centres, botanic gardens, zoos and science museums) and the virtual worlds that are increasingly available through information and communications technologies (ICT)

    Impact of calcium on salivary α-amylase activity, starch paste apparent viscosity and thickness perception

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    Thickness perception of starch-thickened products during eating has been linked to starch viscosity and salivary amylase activity. Calcium is an essential cofactor for α-amylase and there is anecdotal evidence that adding extra calcium affects amylase activity in processes like mashing of beer. The aims of this paper were to (1) investigate the role of salivary calcium on α-amylase activity and (2) to measure the effect of calcium concentration on apparent viscosity and thickness perception when interacting with salivary α-amylase in starch-based samples. α-Amylase activity in saliva samples from 28 people was assessed using a typical starch pasting cycle (up to 95 °C). The activity of the enzyme (as measured by the change in starch apparent viscosity) was maintained by the presence of calcium, probably by protecting the enzyme from heat denaturation. Enhancement of α-amylase activity by calcium at 37 °C was also observed although to a smaller extent. Sensory analysis showed a general trend of decreased thickness perception in the presence of calcium, but the result was only significant for one pair of samples, suggesting a limited impact of calcium enhanced enzyme activity on perceived thickness
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