5,135 research outputs found
Cortical inputs to the middle temporal visual area in New World owl monkeys
We made eight retrograde tracer injections into the middle temporal visual area (MT) of three New World owl monkeys (Aotus nancymaae). These injections were placed across the representation of the retina in MT to allow us to compare the locations of labeled cells in other areas in order to provide evidence for any retinotopic organization in those areas. Four regions projected to MT: 1) early visual areas, including V1, V2, V3, the dorsolateral visual area, and the dorsomedial visual area, provided topographically organized inputs to MT; 2) all areas in the MT complex (the middle temporal crescent, the middle superior temporal area, and the fundal areas of the superior temporal sulcus) projected to MT. Somewhat variably across injections, neurons were labeled in other parts of the temporal lobe; 3) regions in the location of the medial visual area, the posterior parietal cortex, and the lateral sulcus provided other inputs to MT; 4) finally, projections from the frontal eye field, frontal visual field, and prefrontal cortex were also labeled by our injections. These results further establish the sources of input to MT, and provide direct evidence within and across cases for retinotopic patterns of projections from early visual areas to MT
Fire dynamics of the Bolivian Amazon
This study identifies the spatial and temporal trends, as well as the drivers, of fire dynamics in the Bolivian Amazon basin. Bolivia ranks in the top ten countries in terms of total annual burnt, with fires affecting an estimated 2.3 million hectares of forest in 2020. However, in comparison to the Brazilian Amazon, there has been little research into the fire regime in Bolivia. The sparse research and the limited literature on the subject indicate that fire activity is higher in the Bolivian Amazon basin’s dry forests and flooded savanna zones, and that agriculture and drought are the primary causes of fire activity. In this study, trend analysis and emerging hotspot analysis are deployed to identify the spatial and temporal patterns of fire activity and boosted regression tree models to identify the drivers of forest fire within each ecoregion of the Bolivian Amazon basin. Comparable to most of the Brazilian literature, this study finds that fire activity and fire season length is higher in the flooded Beni Savanna, and Chiquitano seasonally dry tropical forests than in the Bolivian Amazon ecoregion. This study also identifies moisture stress and human activity as the main drivers of fire dynamics within the region. It is intended that this research will offer a foundation for future research and conservation activities aimed at better understanding the fire regime of the Bolivian Amazon basin
Host Selection of the giant willow aphid (Tuberolachnus salignus)
The giant willow aphid [Tuberolachnus salignus (Gmelin)] has recently become noteworthy as a potential pest species due to the increased uptake of willow, its host-plant, for use in growing biomass for energy production. In this paper we describe host selection studies of T. salignus on short rotation coppice (SRC) willow varieties in laboratory bioassays and field experiments. In laboratory olfactometry tests, T. salignus was significantly attracted to certain SRC willow varieties, but not to others. Field trials during 2007 and 2008 showed that T. salignus infestation levels varied significantly on different SRC willow varieties and that levels are highest on the varieties to which they are most strongly attracted in the laboratory bioassays
Benchmarking vector arthropod culture: an example using the African malaria mosquito, Anopheles gambiae (Diptera: Culicidae)
BACKGROUND: Numerous important characteristics of adult arthropods are related to their size; this is influenced by conditions experienced as immatures. Arthropods cultured in the laboratory for research, or mass-reared for novel control methods, must therefore be of a standard size range and known quality so that results are reproducible. METHODS: A simple two-step technique to assess laboratory culture methods was demonstrated using the mosquito Anopheles gambiae s.s. as a model. First, the ranges of key development outcomes were determined using various diet levels. The observed outcomes described the physiologically constrained limits. Secondly, the same outcomes were measured when using a standard operating procedure (SOP) for comparison with the determined ranges. RESULTS: The standard method resulted in similar development rates to those of high and medium diets, wing length between those resulting from the high and medium diets, and larval survival exceeding all benchmark diet level values. The SOP used to produce experimental material was shown to produces high-quality material, relative to the biologically constrained limits. CONCLUSIONS: The comparison between all possible phenotypic outcomes, as determined by biological constraints, with those outcomes obtained using a given rearing protocol is termed âbenchmarkingâ. A method is here demonstrated which could be easily adapted to other arthropods, to objectively assess important characters obtained, and methods used, during routine culture that may affect outcomes of research. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12936-016-1288-4) contains supplementary material, which is available to authorized users
Benchmarking vector arthropod culture: an example using the African malaria mosquito, Anopheles gambiae (Diptera: Culicidae)
Background: Numerous important characteristics of adult arthropods are related to their size; this is influenced by conditions experienced as immatures. Arthropods cultured in the laboratory for research, or mass-reared for novel control methods, must therefore be of a standard size range and known quality so that results are reproducible.Methods: A simple two-step technique to assess laboratory culture methods was demonstrated using the mosquito Anopheles gambiae s.s. as a model. First, the ranges of key development outcomes were determined using various diet levels. The observed outcomes described the physiologically constrained limits. Secondly, the same outcomes were measured when using a standard operating procedure (SOP) for comparison with the determined ranges.Results: The standard method resulted in similar development rates to those of high and medium diets, wing length between those resulting from the high and medium diets, and larval survival exceeding all benchmark diet level values. The SOP used to produce experimental material was shown to produces high-quality material, relative to the biologically constrained limits.Conclusions: The comparison between all possible phenotypic outcomes, as determined by biological constraints, with those outcomes obtained using a given rearing protocol is termed âbenchmarkingâ. A method is here demonstrated which could be easily adapted to other arthropods, to objectively assess important characters obtained, and methods used, during routine culture that may affect outcomes of research
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Near wall hemodynamics: Modelling the glycocalyx and the endothelial surface
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.In this paper a coarse-grained model for blood flow in small arteries is presented. Blood is modelled as a two-component incompressible fluid: the plasma and corpuscular elements dispersed in it. The latter are modelled as deformable liquid droplets having greater density and viscosity. Interfacial surface tension and membrane effects are present to mimic key properties and to avoid dropletsâ coalescence. The mesoscopic model also includes the presence of the wavy wall, due to the endothelial cells and incorporates a representation of the glycocalyx, covering the vessel wall. The glycocalyx is modelled as a porous medium, the droplets being subjected to a repulsive elastic force when approaching it, during their transit. Preliminary simulations are intended to show the influence of the undulation on the wall together with that of the glycocalyx
Psychosocial Contexts of Diabetes and Older Adulthood: Reciprocal Effects
The present study was conducted to assess the reciprocal effects between the psychosocial contexts of diabetes and older adulthood. Data were collected from 191 community-dwelling adults over the age of 60 with non-insulin-dependent diabetes mellitus. Results indicate that older adults with diabetes reported higher rates of selected chronic illnesses, lower self-rated physical health, and higher levels of depression than did comparison samples of older adults without diabetes. Compared with younger adults with NIDDM, the present sample of older adults perceived fewer impacts of diabetes, including fewer symptoms of poor metabolic control, less emotional impact, fewer barriers to adherence, and less complex regimens. Overall levels of social support and regimen adherence were high. Older adults in this sample reported wanting minimal help from their family and friends with self-management activities and receiving more help than desired with following a meal plan and taking medications. Implications of the unique context of older adulthood for diabetes self-management are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69058/2/10.1177_014572179101700507.pd
The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the Anopheles gambiae complex in Bana, a west African humid savannah village
BACKGROUND: Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village. METHODS: Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407-5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling. RESULTS: Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000-50,000) to the wet season (100,000-500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549Â m over the seven days of each study and was not influenced by the season, but mainly by the release location, which explained more than 44% of the variance in net dispersal distance. CONCLUSION: This study clearly shows that male-based MRR experiments can be used to estimate some parameters of wild male populations such as population size, survival, and dispersal and to estimate the spatial patterns of movement in a given locality
Woodland expansion in upland national parks: an analysis of stakeholder views and understanding in the Dartmoor National Park, UK
Woodland expansion on a significant scale is widely seen to be critical if governments are to achieve their net zero greenhouse gas ambitions. The United Kingdom government is committed to expanding tree cover from 13% to at least 17% in order to achieve net zero by 2050. With much lowland area under agricultural production, woodland expansion may be directed to upland areas, many of which are national parks under some degree of conservation jurisdiction. This may prove to be controversial, requiring full engagement with the interests of those individuals with a stake in their protection and management. In this paper, we explore how a range of stakeholders view the prospect of woodland expansion in Dartmoor National Park in southwest England, UK. Fifteen stakeholdersâa mix of key informants and farmersâwere shown different woodland expansion scenarios in map form and consulted using semi-structured interviews. The findings suggest widespread enthusiasm for woodland expansion, but with significant differences in terms of the scale and approach. Stakeholders raised topics of biodiversity gain, climate change mitigation, environmental benefits, cultural ecosystem gain, and forest crop benefits. Caution was expressed regarding target setting, the place of woodland expansion in the national debate, and the potential for harm from inappropriate new planting. The constraints identified were land tenure patterns, notably tenancy insecurity and âcommon landâ challenges, historical farming policy and culture, landscape objectives, and future policy design
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