1,011 research outputs found

    Behavioral phenotypes of impulsivity related to the ANKK1 gene are independent of an acute stressor

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    <p>Abstract</p> <p>Background</p> <p>The A1 allele of the <it>ANKK1 Taq</it>IA polymorphism (previously reported as located in the D2 dopamine receptor (DRD2) gene) is associated with reduced DRD2 density in the striatum and with clinical disorders, particularly addiction. It was hypothesized that impulsivity represents an endophenotype underlying these associations with the <it>Taq</it>IA and that environmental stress would moderate the strength of the gene-behavior relationship.</p> <p>Methods</p> <p><it>Taq</it>IA genotyping was conducted on 72 healthy young adults who were randomly allocated to either an acute psychosocial stress or relaxation induction condition. Behavioral phenotypes of impulsivity were measured using a card-sorting index of reinforcement sensitivity and computerized response inhibition and delay discounting tasks.</p> <p>Results</p> <p>Separate analyses of variance revealed associations between the A1 allele and two laboratory measures of impulsivity. The presence of the <it>Taq</it>IA allele (A1+) was associated with slower card-sorting in the presence of small financial reinforcers, but was overcome in a second administration after either a five-minute rest or psychosocial stress induction. A1+ participants also demonstrated significantly poorer response inhibition and faster response times on a computerized stop inhibition task, independent of acute stress exposure.</p> <p>Conclusion</p> <p>These findings indicate the A1 allele is associated with an endophenotype comprising both a "rash impulsive" behavioral style and reinforcement-related learning deficits. These effects are independent of stress.</p

    Assessment of the accuracy of counting large ungulate species (red deer Cervus elaphus) with UAV‐mounted thermal infrared cameras during night flights

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    Unmanned aerial vehicles (UAVs) are increasingly used in wildlife surveying, including estimation of population densities. It is essential that we evaluate and test new survey methods to guide optimal sampling strategies. This study aimed to assess the accuracy of using a UAV-mounted thermal infrared (TIR) camera to count red deer Cervus elaphus populations, and how this was influenced by flight season, height and velocity, in order to help guide future census design. We flew 57 flights across a captive population of red deer in a 13 ha deer park enclosure of semi-natural habitat, representative of the species' range in northern Germany. Flights and image assessments were performed with no prior knowledge of actual population size. Accuracy was quantified by comparing real population size (known only to deer park staff) and independently estimated population sizes from UAV TIR images. Accuracy was significantly influenced by ecological season (early and late winter, spring and early summer) and height. Across all seasons, lower flights (100 m) performed better than higher ones (120 m), with lower flights in early winter and early summer being on average accurate to within 1% of actual population counts. For the season where we had the largest range of temperatures between flights (late winter) we found that accuracy was highest when temperatures were lowest. Flights were also able to identify all five stags (defined as a male deer ≄ 2 years old) present in early summer, but not in spring. Deer appeared to avoid the landing/take-off area, but there were no noted behavioural responses to drones flying over animals when at constant height and velocity during surveys. Our results indicate that UAV-mounted TIR camera have the potential to accurately count populations of large ungulate species, but that flight season, height and potentially temperature need to be taken into account to maximise accuracy. This approach has the potential to be scaled up to more accurately estimate densities of wild populations compared to existing approaches

    Optimising camera trap data quality at mammal resting places.

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    A thorough understanding of how camera traps function is essential for ensuring correct set-up and quality of data. We illustrate the challenges through a case study of camera trapping an otter Lutra lutra resting and breeding place. Appropriate survey design, such as using multiple cameras, decreasing the distance between cameraand otter holt entrance, and camera trapping for sufficient duration, is likely to reduce the propensity for false negatives and increase our ability to correctly identify and protect mammal resting places

    Component processes of detection probability in camera-trap studies: understanding the occurrence of false-negatives

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    Camera-trap studies in the wild record true-positive data, but data loss from false-negatives (i.e. an animal is present but not recorded) is likely to vary and widely impact data quality. Detection probability is defined as the probability of recording an animal if present in the study area. We propose a framework of sequential processes within detection-a pass, trigger, image registration, and images being of sufficient quality. Using Closed Circuit TV (CCTV) combined with camera-trap arrays we quantified variation in, and drivers of, these processes for three medium sized mammal species. We also compared trigger success of wet and dry otter Lutra lutra, as an example of a semi-aquatic species. Data loss from failed trigger, failed registration and poor capture quality varied between species, camera-trap model and settings, and were affected by different environmental and animal variables. Distance had a negative effect on trigger probability and a positive effect on registration probability. Faster animals had both reduced trigger and registration probabilities. Close passes (1m) frequently did not generate triggers, resulting in over 20% data loss for all species. Our results, linked to the framework describing processes, can inform study design to minimise, or account for data loss during analysis and interpretation

    Optimising camera trap data quality at mammal resting places.

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    A thorough understanding of how camera traps function is essential for ensuring correct set-up and quality of data. We illustrate the challenges through a case study of camera trapping an otter Lutra lutra resting and breeding place. Appropriate survey design, such as using multiple cameras, decreasing the distance between cameraand otter holt entrance, and camera trapping for sufficient duration, is likely to reduce the propensity for false negatives and increase our ability to correctly identify and protect mammal resting places

    Environmental release, fate and ecotoxicological effects of manufactured ceria nanomaterials

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    Recent interest in the environmental fate and effects of manufactured CeO2 nanomaterials (nanoceria) has stemmed from its expanded use for a variety of applications including fuel additives, catalytic converters, chemical and mechanical planarization media and other uses. This has led to a wave of publications on the toxicological effects of nanoceria in ecological receptor species, but only limited information is available on possible environmental releases, concentrations in environmental media, or environmental transformations. In this paper, we make initial estimates of likely environmental releases and exposure concentrations in soils and water and compare them to published toxicity values. Insufficient information was available to estimate aquatic exposures, but we estimated inputs to a hypothetical wastewater treatment plant that could result in effluent concentrations that would result in acute toxicity to the most sensitive aquatic organisms tested so far, cyanobacteria. The purpose of this exercise is to identify which areas are lacking in data to perform either regional or site specific ecological risk assessments. While estimates can be made for releases from use as a diesel fuel additive, and predicted toxicity is low in most terrestrial species tested to date, estimates for releases from other uses are difficult at this stage. We recommend that future studies focus on environmentally realistic exposures that take into account potential environmental transformations of the nanoceria surface as well as chronic toxicity studies in benthic aquatic organisms, soil invertebrates and microorgansims

    Cortical Tension Allocates the First Inner Cells of the Mammalian Embryo

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    Every cell in our body originates from the pluripotent inner mass of the embryo, yet it is unknown how biomechanical forces allocate inner cells in vivo. Here we discover subcellular heterogeneities in tensile forces, generated by actomyosin cortical networks, which drive apical constriction to position the first inner cells of living mouse embryos. Myosin II accumulates specifically around constricting cells, and its disruption dysregulates constriction and cell fate. Laser ablations of actomyosin networks reveal that constricting cells have higher cortical tension, generate tension anisotropies and morphological changes in adjacent regions of neighboring cells, and require their neighbors to coordinate their own changes in shape. Thus, tensile forces determine the first spatial segregation of cells during mammalian development. We propose that, unlike more cohesive tissues, the early embryo dissipates tensile forces required by constricting cells via their neighbors, thereby allowing confined cell repositioning without jeopardizing global architecture.Fil: Samarage, Chaminda R.. Monash University; AustraliaFil: White, Melanie D.. Monash University; AustraliaFil: Alvarez, Yanina Daniela. Monash University; Australia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Fierro GonzĂĄlez, Juan Carlos. Monash University; AustraliaFil: Henon, Yann. Monash University; AustraliaFil: Jesudason, Edwin C.. National Health Service Scotland; Reino UnidoFil: Bissiere, Stephanie. Monash University; Australia. Institute of Molecular and Cell Biology; SingapurFil: Fouras, Andreas. Monash University; AustraliaFil: Plachta, Nicolas. Monash University; Australia. Institute of Molecular and Cell Biology; Singapu

    Study protocol: evaluation of a parenting and stress management programme: a randomised controlled trial of Triple P discussion groups and stress control

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    &lt;br&gt;Background: Children displaying psychosocial problems are at an increased risk of negative developmental outcomes. Parenting practices are closely linked with child development and behaviour, and parenting programmes have been recommended in the treatment of child psychosocial problems. However, parental mental health also needs to be addressed when delivering parenting programmes as it is linked with parenting practices, child outcomes, and treatment outcomes of parenting programmes. This paper describes the protocol of a study examining the effects of a combined intervention of a parenting programme and a cognitive behavioural intervention for mental health problems.&lt;/br&gt; &lt;br&gt;Methods: The effects of a combined intervention of Triple P Discussion Groups and Stress Control will be examined using a randomised controlled trial design. Parents with a child aged 3?8?years will be recruited to take part in the study. After obtaining informed consent and pre-intervention measures, participants will be randomly assigned to either an intervention or a waitlist condition. The two primary outcomes for this study are change in dysfunctional/ineffective parenting practices and change in symptoms of depression, anxiety, and stress. Secondary outcomes are child behaviour problems, parenting experiences, parental self-efficacy, family relationships, and positive parental mental health. Demographic information, participant satisfaction with the intervention, and treatment fidelity data will also be collected. Data will be collected at pre-intervention, mid-intervention, post-intervention, and 3-month follow-up.&lt;/br&gt; &lt;br&gt;Discussion: The aim of this paper is to describe the study protocol of a randomised controlled trial evaluating the effects of a combined intervention of Triple P Discussion Groups and Stress Control in comparison to a waitlist condition. This study is important because it will provide evidence about the effects of this combined intervention for parents with 3?8?year old children. The results of the study could be used to inform policy about parenting support and support for parents with mental health problems. Trial registration ClinicalTrial.gov: NCT01777724, UTN: U1111-1137-1053.&lt;/br&gt
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