145 research outputs found
Optimising targets for tsetse control:Taking a flyâs-eye-view to improve the colour of synthetic fabrics
The savannah tsetse flies, Glossina morsitans morsitans and G. pallidipes, are important vectors of Rhodesian human African trypanosomiasis and animal African trypanosomiasis in East and southern Africa. We tested in Zimbabwe whether robust, synthetic fabrics, and innovative flyâs-eye-view approaches to optimise fabric colour, can improve insecticide-treated targets employed for tsetse control. Flies were caught by electrocution at a standard target comprising a 1m x 1m black cotton cloth panel with 1m x 0.5m black polyester net panels on each side. Catches were subdivided by species and sex. Tsetse catches were unaffected by substitution of the black cotton with a blue polyester produced for riverine tsetse targets. Exchanging the net panels for phthalogen blue cotton to simulate the target routinely used in Zimbabwe significantly reduced catches of female G. m. morsitans (mean catch 0.7 times that at standard), with no effect on other tsetse catches. However, significantly greater proportions of the catch were intercepted at the central panel of the Zimbabwe (means 0.47â0.79) versus standard designs (0.11â0.29). We also engineered a new violet polyester cloth using models of tsetse attraction based upon fly photoreceptor responses. With and without odour lure, catches of females of both species at the violet target were significantly greater than those at standard (means 1.5â1.6 times those at standard), and typical blue polyester targets (means 0.9â1.3 times those at standard). Similar effects were observed for males under some combinations of species and odour treatment. The proportions of catch intercepted at the central panel of the violet target (means 0.08â0.18) were intermediate between those at standard and typical blue polyester. Further, the reflectance spectrum of violet polyester was more stable under field conditions than that of black cotton. Our results demonstrate the effectiveness of photoreceptor-based models as a novel means of improving targets to control tsetse and trypanosomiases
Altitude dependence of atmospheric temperature trends: Climate models versus observation
As a consequence of greenhouse forcing, all state of the art general
circulation models predict a positive temperature trend that is greater for the
troposphere than the surface. This predicted positive trend increases in value
with altitude until it reaches a maximum ratio with respect to the surface of
as much as 1.5 to 2.0 at about 200 to 400 hPa. However, the temperature trends
from several independent observational data sets show decreasing as well as
mostly negative values. This disparity indicates that the three models examined
here fail to account for the effects of greenhouse forcings.Comment: 9 pages, 3 figure
Light-Induced Manipulation of Passive and Active Microparticles
We consider sedimented at a solid wall particles that are immersed in water
containing small additives of photosensitive ionic surfactants. It is shown
that illumination with an appropriate wavelength, a beam intensity profile,
shape and size could lead to a variety of dynamic, both unsteady and
steady-state, configurations of particles. These dynamic, well-controlled and
switchable particle patterns at the wall are due to an emerging
diffusio-osmotic flow that takes its origin in the adjacent to the wall
electrostatic diffuse layer, where the concentration gradients of surfactant
are induced by light. The conventional nonporous particles are passive and can
move only with already generated flow. However, porous colloids actively
participate themselves in the flow generation mechanism at the wall, which also
sets their interactions that can be very long ranged. This light-induced
diffusio-osmosis opens novel avenues to manipulate colloidal particles and
assemble them to various patterns. We show in particular how to create and
split optically the confined regions of particles of tunable size and shape,
where well controlled flow-induced forces on the colloids could result in their
cristalline packing, formation of dilute lattices of well-separated particles,
and other states.Comment: 11 pages, 14 figure
Enabling the Participation of People with Parkinson's and Their Caregivers in Co-Inquiry around Collectivist Health Technologies
While user participation is central to HCI, co-inquiry takes this further by having participants direct and control research from conceptualisation to completion. We describe a co-inquiry, conducted over 16 months with a Parkinson's support group. We explored how the participation of members might be enabled across multiple stages of a research project, from the generation of research questions to the development of a prototype. Participants directed the research into developing alternative modes of information provision, resulting in âParkinsonâs Radioâ â a collectivist health information service produced and edited by members of the support group. We reflect on how we supported participation at different stages of the project and the successes and challenges faced by the team. We contribute insights into the design of collectivist health technologies for this group, and discuss opportunities and tensions for conducting co-inquiry in HCI research
Photoswitchable precision glycooligomers and their lectin binding
The synthesis of photoswitchable glycooligomers is presented by applying solid-phase polymer synthesis and functional building blocks. The obtained glycoligands are monodisperse and present azobenzene moieties as well as sugar ligands at defined positions within the oligomeric backbone and side chains, respectively. We show that the combination of molecular precision together with the photoswitchable properties of the azobenzene unit allows for the photosensitive control of glycoligand binding to protein receptors. These stimuli-sensitive glycoligands promote the understanding of multivalent binding and will be further developed as novel biosensors
Observed multivariable signals of late 20th and early 21st century volcanic activity
The relatively muted warming of the surface and lower troposphere since 1998 has attracted considerable attention. One contributory factor to this âwarming hiatusâ is an increase in volcanically induced cooling over the early 21st century. Here we identify the signals of late 20th and early 21st century volcanic activity in multiple observed climate variables. Volcanic signals are statistically discernible in spatial averages of tropical and near-global SST, tropospheric temperature, net clear-sky short-wave radiation, and atmospheric water vapor. Signals of late 20th and early 21st century volcanic eruptions are also detectable in near-global averages of rainfall. In tropical average rainfall, however, only a Pinatubo-caused drying signal is identifiable. Successful volcanic signal detection is critically dependent on removal of variability induced by the El NinoâSouthern Oscillation.National Science Foundation (U.S.) (Grant AGS-1342810
Detection and Attribution of Temperature Changes in the Mountainous Western United States
Large changes in the hydrology of the western United States have been observed since the mid-twentieth century. These include a reduction in the amount of precipitation arriving as snow, a decline in snowpack at low and midelevations, and a shift toward earlier arrival of both snowmelt and the centroid (center of mass) of streamflows. To project future water supply reliability, it is crucial to obtain a better understanding of the underlying cause or causes for these changes. A regional warming is often posited as the cause of these changes without formal testing of different competitive explanations for the warming. In this study, a rigorous detection and attribution analysis is performed to determine the causes of the late winter/early spring changes in hydrologically relevant temperature variables over mountain ranges of the western United States. Natural internal climate variability, as estimated from two long control climate model simulations, is insufficient to explain the rapid increase in daily minimum and maximum temperatures, the sharp decline in frost days, and the rise in degree-days above 0°C (a simple proxy for temperature-driven snowmelt). These observed changes are also inconsistent with the model-predicted responses to variability in solar irradiance and volcanic activity. The observations are consistent with climate simulations that include the combined effects of anthropogenic greenhouse gases and aerosols. It is found that, for each temperature variable considered, an anthropogenic signal is identifiable in observational fields. The results are robust to uncertainties in model-estimated fingerprints and natural variability noise, to the choice of statistical downscaling method, and to various processing options in the detection and attribution method.California Energy Commission///Estados UnidosU.S. Department of Energy/[DE-AC52-07NA27344]//Estados UnidosUniversidad de Costa Rica//UCR/Costa RicaUCR::VicerrectorĂa de InvestigaciĂłn::Unidades de InvestigaciĂłn::Ciencias BĂĄsicas::Centro de Investigaciones GeofĂsicas (CIGEFI
Attribution of Declining Western U.S. Snowpack to Human Effects
Observations show snowpack has declined across much of the western United States over the period 1950â99. This reduction has important social and economic implications, as water retained in the snowpack from winter storms forms an important part of the hydrological cycle and water supply in the region. A formal model-based detection and attribution (DâA) study of these reductions is performed. The detection variable is the ratio of 1 April snow water equivalent (SWE) to water-year-to-date precipitation (P), chosen to reduce the effect of P variability on the results. Estimates of natural internal climate variability are obtained from 1600 years of two control simulations performed with fully coupled oceanâatmosphere climate models. Estimates of the SWE/P response to anthropogenic greenhouse gases, ozone, and some aerosols are taken from multiple-member ensembles of perturbation experiments run with two models. The DâA shows the observations and anthropogenically forced models have greater SWE/P reductions than can be explained by natural internal climate variability alone. Model-estimated effects of changes in solar and volcanic forcing likewise do not explain the SWE/P reductions. The mean model estimate is that about half of the SWE/P reductions observed in the west from 1950 to 1999 are the result of climate changes forced by anthropogenic greenhouse gases, ozone, and aerosols.Lawrence Livermore National Laboratory///Estados UnidosScripps Institution of Oceanography//SIO/Estados UnidosMinistry of Education, Culture, Sports, Science and Technology///JapĂłnCalifornia Energy Commission///Estados UnidosProgram of Climate Model Diagnosis and Intercomparison/[DOE-W-7405-ENG-48]/PCMDI/Estados UnidosUCR::VicerrectorĂa de InvestigaciĂłn::Unidades de InvestigaciĂłn::Ciencias BĂĄsicas::Centro de Investigaciones GeofĂsicas (CIGEFI
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Challenges in quantifying changes in the global water cycle
Human influences have likely already impacted the large-scale water cycle but natural variability and observational uncertainty are substantial. It is essential to maintain and improve observational capabilities to better characterize changes. Understanding observed changes to the global water cycle is key to predicting future climate changes and their impacts. While many datasets document crucial variables such as precipitation, ocean salinity, runoff, and humidity, most are uncertain for determining long-term changes. In situ networks provide long time-series over land but are sparse in many regions, particularly the tropics. Satellite and reanalysis datasets provide global coverage, but their long-term stability is lacking. However, comparisons of changes among related variables can give insights into the robustness of observed changes. For example, ocean salinity, interpreted with an understanding of ocean processes, can help cross-validate precipitation. Observational evidence for human influences on the water cycle is emerging, but uncertainties resulting from internal variability and observational errors are too large to determine whether the observed and simulated changes are consistent. Improvements to the in situ and satellite observing networks that monitor the changing water cycle are required, yet continued data coverage is threatened by funding reductions. Uncertainty both in the role of anthropogenic aerosols, and due to large climate variability presently limits confidence in attribution of observed changes
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