1,071 research outputs found

    The avian community structure of a Bolivian savanna on the edge of the Cerrado system

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    Se estudió la estructura de una comunidad de aves en una sabana boliviana al borde del Cerrado, entre Agosto y septiembre de 1994, usando transectas de línea. La avifauna de dos hábitats, llamados campo húmedo y campo denso, se describe en detalle. Se identificó un tercer hábitat, la sabana arbolada, pero sólo se describe brevemente. La diversidad de los hábitats se comparó con otros sitios tropicales. Las áreas de campo húmedo tuvieron la mayor densidad de aves, pero en una comunidad relativamente simple, formada principalmente por granívoros que forrajeban en el suelo. El campo denso, con una mayor cobertura vegetal, tuvo mas diversidad de gremios de forrajeo, incluyendo frugívoros, insectívoros y omnívoros, los que mostraron variadas conductas y sitios de alimentación. Consecuentemente este hábitat contuvo el mayor número de especies. La diversidad de aves estuvo correlacionada con la estructura de la vegetación y abundancia de nichos.The avian community structure of a Bolivian savanna on the edge of the Cerrado ecosystem was studied during August and September 1994, using line-transects. The avifauna of two habitats, wet campo and dense campo, is described in detail. A third habitat, wooded savanna, is identified, but only briefly described due to limited survey effort. The diversity of these habitats is compared to data from other tropical studies. Areas of wet campo contained the greatest density of birds, but were characterized by a relatively simple bird community, formed prirnari1y of granivorous, ground-gleaning species. Dense campo habitats, characterised by greater vegetation cover, supported a higher diversity of foraging guilds, including frugivores, insectivores and omnivores, exhibiting a variety of foraging strata and behaviours. Consequently, this habitat contained the greatest number of species. Bird species diversity was therefore re1ated to vegetation structure and niche availability

    Regular treatment with formoterol for chronic asthma: serious adverse events

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    Epidemiological evidence has suggested a link between beta(2)-agonists and increases in asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta2-agonists are safe.ObjectivesThe aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular formoterol versus placebo or regular short-acting beta2-agonists.Search methodsWe identified trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trial registers for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to formoterol. The date of the most recent search was January 2012.Selection criteriaWe included controlled, parallel design clinical trials on patients of any age and severity of asthma if they randomised patients to treatment with regular formoterol and were of at least 12 weeks' duration. Concomitant use of inhaled corticosteroids was allowed, as long as this was not part of the randomised treatment regimen.Data collection and analysisTwo authors independently selected trials for inclusion in the review. One author extracted outcome data and the second author checked them. We sought unpublished data on mortality and serious adverse events.Main resultsThe review includes 22 studies (8032 participants) comparing regular formoterol to placebo and salbutamol. Non-fatal serious adverse event data could be obtained for all participants from published studies comparing formoterol and placebo but only 80% of those comparing formoterol with salbutamol or terbutaline.Three deaths occurred on regular formoterol and none on placebo; this difference was not statistically significant. It was not possible to assess disease-specific mortality in view of the small number of deaths. Non-fatal serious adverse events were significantly increased when regular formoterol was compared with placebo (Peto odds ratio (OR) 1.57; 95% CI 1.06 to 2.31). One extra serious adverse event occurred over 16 weeks for every 149 people treated with regular formoterol (95% CI 66 to 1407 people). The increase was larger in children than in adults, but the impact of age was not statistically significant. Data submitted to the FDA indicate that the increase in asthma-related serious adverse events remained significant in patients taking regular formoterol who were also on inhaled corticosteroids.No significant increase in fatal or non-fatal serious adverse events was found when regular formoterol was compared with regular salbutamol or terbutaline.Authors' conclusionsIn comparison with placebo, we have found an increased risk of serious adverse events with regular formoterol, and this does not appear to be abolished in patients taking inhaled corticosteroids. The effect on serious adverse events of regular formoterol in children was greater than the effect in adults, but the difference between age groups was not significant.Data on all-cause serious adverse events should be more fully reported in journal articles, and not combined with all severities of adverse events or limited to those events that are thought by the investigator to be drug-related

    A disruptive alternative to semi-continuous multi-column chromatography processes

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    Protein purification to date is still dominated by expensive chromatography operations. Within the bioprocessing segment of the biopharmaceutical industry, enormous advances in upstream processing performance have moved the cost-reduction bottleneck to downstream processing (DSP). In an effort to reduce DSP costs, the industry is progressively turning to multi-column semi-continuous manufacturing techniques, adapted from neighbouring chemical processing industries. In the case of Affinity Chromatography, the primary theoretical advantage lies in alleviating particularly expensive bind/elute capture steps by allowing saturation of any given unit of resin with product feed while routing the partially depleted effluent flow-through material to follow-on unsaturated resin through the use of multiple columns in a sequence. The saturation better utilises the resin in each of its cycles allowing a reduction in per gram cost and improved time usage, and since saturation can achieve the full static binding capacity without being limited by a dynamic flow, this allows the system to flow faster, saving even more time. However, industrial adoption of these new techniques has been slow, owing to their significant increase in developmental and operational complexity and the capital expense of additional hardware requirements. In this presentation we will reveal and discuss processing factors that may significantly impact the true benefits in speed for multi-column processes, particularly relating to the necessary scheduling effects of aligning multiple synchronous columns, and to back pressure and column height effects that both slow the achievable productivity and mask true comparisons with traditional batch chromatography. We have found scenarios where these factors can combine to make semi-continuous multi-column processes significantly slower than equivalent batch processes, and the loss in productivity can, in some circumstances, cancel much of the cost savings on resin consumption. In an effort to understand, improve and simplify these semi-continuous processes, we internally developed a novel and potentially disruptive operational method that matches or exceeds the benefits of a semi-continuous process, without the complexity. Data from a prototype un-optimised version tested at pilot scale will show that significant performance gains can be achieved on standard chromatography equipment with minimal modification

    Winter wren populations show adaptation to local climate

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    Most studies of evolutionary responses to climate change have focused on phenological responses to warming, and provide only weak evidence for evolutionary adaptation. This could be because phenological changes are more weakly linked to fitness than more direct mechanisms of climate change impacts, such as selective mortality during extreme weather events which have immediate fitness consequences for the individuals involved. Studies examining these other mechanisms may be more likely to show evidence for evolutionary adaptation. To test this, we quantify regional population responses of a small resident passerine (winter wren Troglodytes troglodytes) to a measure of winter severity (number of frost days). Annual population growth rate was consistently negatively correlated with this measure, but the point at which different populations achieved stability (λ = 1) varied across regions and was closely correlated with the historic average number of frost days, providing strong evidence for local adaptation. Despite this, regional variation in abundance remained negatively related to the regional mean number of winter frost days, potentially as a result of a time-lag in the rate of evolutionary response to climate change. As expected from Bergmann's rule, individual wrens were heavier in colder regions, suggesting that local adaptation may be mediated through body size. However, there was no evidence for selective mortality of small individuals in cold years, with annual variation in mean body size uncorrelated with the number of winter frost days, so the extent to which local adaptation occurs through changes in body size, or another mechanism remains uncertain

    Population decline is linked to migration route in the Common Cuckoo

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    Migratory species are in rapid decline globally. Although most mortality in long-distance migrant birds is thought to occur during migration, evidence of conditions on migration affecting breeding population sizes has been completely lacking. We addressed this by tracking 42 male Common Cuckoos from the rapidly declining UK population during 56 autumn migrations in 2011–14. Uniquely, the birds use two distinct routes to reach the same wintering grounds, allowing assessment of survival during migration independently of origin and destination. Mortality up to completion of the Sahara crossing (the major ecological barrier encountered in both routes) is higher for birds using the shorter route. The proportion of birds using this route strongly correlates with population decline across nine local breeding populations. Knowledge of variability in migratory behaviour and performance linked to robust population change data may therefore be necessary to understand population declines of migratory species and efficiently target conservation resources

    Experimental Evidence for the Effect of Small Wind Turbine Proximity and Operation on Bird and Bat Activity

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    The development of renewable energy technologies such as wind turbines forms a vital part of strategies to reduce greenhouse gas emissions worldwide. Although large wind farms generate the majority of wind energy, the small wind turbine (SWT, units generating <50 kW) sector is growing rapidly. In spite of evidence of effects of large wind farms on birds and bats, effects of SWTs on wildlife have not been studied and are likely to be different due to their potential siting in a wider range of habitats. We present the first study to quantify the effects of SWTs on birds and bats. Using a field experiment, we show that bird activity is similar in two distance bands surrounding a sample of SWTs (between 6-18 m hub height) and is not affected by SWT operation at the fine scale studied. At shorter distances from operating turbines (0-5 m), bat activity (measured as the probability of a bat "pass" per hour) decreases from 84% (71-91%) to 28% (11-54%) as wind speed increases from 0 to 14 m/s. This effect is weaker at greater distances (20-25 m) from operating turbines (activity decreases from 80% (65-89%) to 59% (32-81%)), and absent when they are braked. We conclude that bats avoid operating SWTs but that this effect diminishes within 20 m. Such displacement effects may have important consequences especially in landscapes where suitable habitat is limiting. Planning guidance for SWTs is currently lacking. Based on our results we recommend that they are sited at least 20 m away from potentially valuable bat habitat
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