1,239 research outputs found

    Recovery of Mycobacterium haemophilum skin infection in an HIV-I-infected patient after the start of antiretroviral triple therapy

    Get PDF
    Constant Rate Thermal Analysis (CRTA) method implies controlling the temperature in such a way that the reaction rate is maintained constant all over the process. This method allows determining simultaneously both the kinetic parameters and the kinetic model from a single experiment as the shape of the CRTA α-T curves strongly depends on the kinetic model. CRTA method has been developed in the market only for thermogravimetric and thermodilatometric systems and, therefore, its use has been limited until now to the kinetic study of processes involving changes in mass or size of the samples, respectively. To overcome this obstacle, a method has been developed in this work for using the DSC signal for controlling the process rate in such a way that CRTA would be applied to the kinetic analysis of either phase transformations or crystallizations. The advantages of CRTA for performing the kinetics of crystallization processes have been here successfully demonstrated for the first time after selecting the crystallization of zirconia gel as test reaction.Ministerio de Economía y Competitividad CTQ2014-52763-C2-1-RJunta de Andalucía TEP-7858, TEP-1900FEDER CTQ2014-52763-C2-1-RFEDER TEP-7858 TEP-190

    Density-dependent switches in diet:a likely mechanism for negative feedbacks on goose population increase?

    Get PDF
    Goose grazing on arctic tundra vegetation has shown both positive and negative effects on subsequent foraging conditions. To understand the potential of a density-dependent feedback on herbivore population size, the relation between grazing pressure and future foraging conditions is essential. We studied the effect of increasing grazing pressure of barnacle geese (Branta leucopsis) on Spitsbergen. During the establishment of a breeding colony in the period 1992-2004, the proportion of graminoids decreased in the diet of wild geese, while the percentage of mosses increased. Grazing trials with captive geese in an unexploited area showed a similar shift in diet composition. High-quality food plants were depleted within years and over years. Intake rate declined too and as consequence, metabolisable energy intake rate (MEIR) decreased rapidly with increasing grazing pressure. During three successive years of experimental grazing, MEIR decreased at all levels of grazing pressure and declined below minimal energetic requirements when grazing exceeded natural levels of grazing pressure. This suggests that foraging conditions rapidly decline with increasing grazing pressure in these low-productive habitats. The potential for density-dependent feedbacks on local population increase is discussed

    Children's Pronoun Interpretation Problems Are Related to Theory of Mind and Inhibition, But Not Working Memory

    Get PDF
    In several languages, including English and Dutch, children’s acquisition of the interpretation of object pronouns (e.g., him) is delayed compared to that of reflexives (e.g., himself). Various syntactic and pragmatic explanations have been proposed to account for this delay in children’s acquisition of pronoun interpretation. This study aims to provide more insight into this delay by investigating potential cognitive mechanisms underlying this delay. Dutch-speaking children between 6 and 12 years old with autism spectrum disorder (ASD; n = 47), attention-deficit/hyperactivity disorder (ADHD; n = 36) or typical development (TD; n = 38) were tested on their interpretation and production of object pronouns and reflexives and on theory of mind, working memory, and response inhibition. It was found that all three groups of children had difficulty with pronoun interpretation and that their performance on pronoun interpretation was associated with theory of mind and inhibition. These findings support an explanation of object pronoun interpretation in terms of perspective taking, according to which listeners need to consider the speaker’s perspective in order to block coreference between the object pronoun and the subject of the same sentence. Unlike what is predicted by alternative theoretical accounts, performance on pronoun interpretation was not associated with working memory, and the children made virtually no errors in their production of object pronouns. As the difficulties with pronoun interpretation were similar for children with ASD, children with ADHD and typically developing children, this suggests that certain types of perspective taking are unaffected in children with ASD and ADHD

    Recreation reduces tick density through fine-scale risk effects on deer space-use

    Get PDF
    Altered interactions between pathogens, their hosts and vectors have potential consequences for human disease risk. Notably, tick-borne pathogens, many of which are associated with growing deer abundance, show global increasing prevalence and pose increasing challenges for disease prevention. Human activities can largely affect the patterns of deer space-use and can therefore be potential management tools to alleviate human-wildlife conflicts. Here, we tested how deer space-use patterns are influenced by human recreational activities, and how this in turn affects the spatial distribution of the sheep tick (Ixodes ricinus), a relevant disease vector of zoonoses such as Lyme borrelioses. We compared deer dropping and questing tick density on transects near (20 m) and further away from(100 m) forest trails that were either frequently used (open for recreation) or infrequently used (closed for recreation, but used by park managers). In contrast to infrequently used trails, deer dropping density was 31% lower near (20 m) than further away from (100 m) frequently used trails. Similarly, ticks were 62% less abundant near (20 m) frequently used trails compared to further away from (100 m) these trails, while this decline in tick numbers was only 14% near infrequently used trails. The avoidance by deer of areas close to human-used trails was thus associated with a similar reduction in questing tick density near these trails. As tick abundance generally correlates to pathogen prevalence, the use of trails for recreation may reduce tick-borne disease risk for humans on and near these trails. Our study reveals an unexplored effect of human activities on ecosystems and how this knowledge could be potentially used to mitigate zoonotic disease risk

    Aerial dissemination of Clostridium difficile spores inside and outside a pig farm

    Get PDF
    In both human and veterinary medicine Clostridium difficile infections are increasingly reported. The observation that aerial dissemination occurs in a hospital environment and can pla a role in the transmission of human C. difficile infection, resulted in the present study to the occurence of airborne C. difficile in, and nearby a pig farm with a high prevalence of C. difficile

    NHI Toetsing, Ontwikkeling en toepassing van methode voor toetsing van NHI 2.1 inclusief vergelijking met NHI 2.0.

    Get PDF
    Dit rapport beschrijft de achtergrond van de methode om NHI2.1 te toetsen aan de criteria die opgesteld zijn door Rijkswaterstaat Waterdienst geldend voor 2010 en bevat de resultaten van die toetsing en de vergelijking met resultaten van NHI2.0. Volgens de criteria is de berekende aan en afvoer van oppervlakte water verbeterd. Op enkele belangrijke meetpunten van de oppervlaktewaterverdeling zijn signifinante verbeteringen te zien

    Recreation and hunting differentially affect deer behaviour and sapling performance

    Get PDF
    Humans are increasingly acknowledged as apex predators that shape landscapes of fear to which herbivores adapt their behaviour. Here, we investigate how humans modify deer space-use and their effects on vegetation at two spatial scales; zones with different types of human use (largescale risk factor) and, nested within that, trails (fine-scale risk factor). In zones with three contrasting types of human activities: 1) no recreation, no hunting, 2) with recreation, no hunting and 3) with recreation and hunting, we linked deer space-use (dropping counts) to browsing intensity, relative growth and survival of planted saplings. Plots were located at two distances to trails (20 versus 100 m) to test how trails affect deer space-use and sapling performance. Additionally, plots were distributed over forest and heathland as risk effects are habitat-dependent. Deer space-use was highest in the zone without recreation or hunting, resulting in higher browsing levels and lower sapling growth and survival, but only in heathland. In contrast, deer space-use and sapling performance did not differ between zones with recreation only and zones with recreation and hunting. Deer dropping counts were lower near trails used for recreation, but this was not associated with browsing impact or sapling performance. Our results show that recreational use modifies deer space-use which is associated with browsing impact on woody vegetation, while seasonal hunting activities in zones with recreation did not have additive year-round effects. Yet, effects were only observed at the larger scale of recreation zones and not near trails. Furthermore, deer space-use was only associated with sapling performance in open heathland, where high visibility presumably increases avoidance behaviour because it increases detectability and decreases escape possibilities. This suggests that recreation creates behaviourally mediated cascading effects that influence vegetation development, yet these effects are context-dependent. We advocate incorporating human-induced fear effects in conservation, management and research

    Recreation reduces tick density through fine-scale risk effects on deer space-use

    Get PDF
    Altered interactions between pathogens, their hosts and vectors have potential consequences for human disease risk. Notably, tick-borne pathogens, many of which are associated with growing deer abundance, show global increasing prevalence and pose increasing challenges for disease prevention. Human activities can largely affect the patterns of deer space-use and can therefore be potential management tools to alleviate human-wildlife conflicts. Here, we tested how deer space-use patterns are influenced by human recreational activities, and how this in turn affects the spatial distribution of the sheep tick (Ixodes ricinus), a relevant disease vector of zoonoses such as Lyme borrelioses. We compared deer dropping and questing tick density on transects near (20 m) and further away from (100 m) forest trails that were either frequently used (open for recreation) or infrequently used (closed for recreation, but used by park managers). In contrast to infrequently used trails, deer dropping density was 31% lower near (20 m) than further away from (100 m) frequently used trails. Similarly, ticks were 62% less abundant near (20 m) frequently used trails compared to further away from (100 m) these trails, while this decline in tick numbers was only 14% near infrequently used trails. The avoidance by deer of areas close to human-used trails was thus associated with a similar reduction in questing tick density near these trails. As tick abundance generally correlates to pathogen prevalence, the use of trails for recreation may reduce tick-borne disease risk for humans on and near these trails. Our study reveals an unexplored effect of human activities on ecosystems and how this knowledge could be potentially used to mitigate zoonotic disease risk

    Clostridium difficile Ribotype 027, Toxinotype III, the Netherlands

    Get PDF
    Outbreaks due to Clostridium difficile polymerase chain reaction (PCR) ribotype 027, toxinotype III, were detected in 7 hospitals in the Netherlands from April 2005 to February 2006. One hospital experienced at the same time a second outbreak due to a toxin A–negative C. difficile PCR ribotype 017 toxinotype VIII strain. The outbreaks are difficult to control
    • …
    corecore