58,045 research outputs found
The impact of climate change on aquatic risk from agricultural pesticides in the US
Agricultural pesticides have adverse impacts on water quality and aquatic species. These impacts are sensitive to climate because pest pressure and corresponding pesticide application rates vary with weather and climate conditions. In this paper, we investigate how climate change affects the acute and chronic toxicity risk to algae, daphnia, and fish from the ten most hazardous pesticides in twelve coastal states of the US. We combine climate change projections from the Canadian and Hadley climate model, statistically estimated dependencies of pesticide applications to climate and weather variables, and the environmental risk indicator REXTOX developed by the OECD. On average, we find that climate change is likely to increase the toxicity risk to aquatic species because of increased application of agricultural pesticides. Algae appear to be the most negatively affected category. Across five broad crop groups, pesticide use on fruits and vegetables contributes the most to increased aquatic pollution. Within the twelve coastal states, the highest impacts are found in Texas, Florida, California, South and North Carolina.climate change scenarios, agricultural pesticides, acute toxicity, chronic risk, aquatic species, marine environment, United States
Implications of the isotope effects on the magnetization, magnetic torque and susceptibility
We analyze the magnetization, magnetic torque and susceptibility data of
La2-xSrxCu(16,18)O4 and YBa2(63,65)CuO7-x near Tc in terms of the universal
3D-XY scaling relations. It is shown that the isotope effect on Tc mirrors that
on the anisotropy. Invoking the generic behavior of the anisotropy the doping
dependence of the isotope effects on the critical properties, including Tc,
correlation lengths and magnetic penetration depths are traced back to a change
of the mobile carrier concentration.Comment: 5 pages, 3 figure
On the Unique Solution of Planet and Star Parameters from an Extrasolar Planet Transit Light Curve
There is a unique solution of the planet and star parameters from a planet
transit light curve with two or more transits if the planet has a circular
orbit and the light curve is observed in a band pass where limb darkening is
negligible. The existence of this unique solution is very useful for current
planet transit surveys for several reasons. First, there is an analytic
solution that allows a quick parameter estimate, in particular of Rp. Second,
the stellar density can be uniquely derived from the transit light curve alone.
The stellar density can be used to immediately rule out a giant star (and hence
a much larger than planetary companion) and can also be used to put an upper
limit on the stellar and planet radius even considering slightly evolved stars.
Third, the presence of an additional fully blended star that contaminates an
eclipsing system to mimic a planet transit can be largely ruled out from the
transit light curve given a spectral type for the central star. Fourth, the
period can be estimated from a single-transit light curve and a measured
spectral type. All of these applications can be used to select the best planet
transit candidates for mass determination by radial velocity follow-up. To use
these applications in practice, the photometric precision and time sampling of
the light curve must be high (better than 0.005 mag precision and 5 minute time
sampling).Comment: 26 pages incl. 11 figs, submitted to Ap
Pesticide externalities from the US agricultural sector -- The impact of internalization, reduced pesticide application rates, and climate change
Pesticides used in agricultural production affect environmental quality and human health. These external costs can amplify due to climate change because pest pressure and optimal pesticide application rates vary with weather and climate conditions. This study uses mathematical programming to examine alternative assumptions about regulations of external costs from pesticide applications in US agriculture. We use two climate projections given by the Canadian and Hadley climate models. The impacts of the internalization of the pesticide externality and climate change are assessed both independently and jointly. We find that, without external cost regulation, climate change benefits from increased agricultural production in the US may be more than offset by increased environmental costs. The internalization of the pesticide externalities increase farmers’ production costs but increase farmers’ income because of price adjustments and associated welfare shifts from consumers to producers. Our results also show that full internalizations of external pesticide costs substantially reduces preferred pesticide applications rates for corn and soybeans as climate change.climate change impacts, pesticide externalities, farm management adaptation, agricultural sector model, welfare maximization, environmental policy analysis, mathematical programming, United States
Vaccination of Cows with a Combined Rotavirus/Enterotoxigenic "E. Coli" K99 Vaccine to Protect Newborn Calves Against Diarrhoea
The impact of weather variability and climate change on pesticide applications in the US - An empirical investigation
Weather variability and climate change affect the application of pesticides in agriculture, in turn impacting the environment. Using panel data regression for the US, we find that weather and climate differences significantly influence the application rates of most pesticides. Subsequently, the regression results are linked to downscaled climate change scenario the Canadian and Hadley climate change models. We find that the application of most pesticides increase under both scenarios. The projection results vary by crop, region, and pesticide.Climate change, weather variability, pesticide, regression, panel data, North America, US
A possible solution of the grain boundary problem for applications of high-Tc superconductors
It is shown that the critical current density of high-Tc wires can be greatly
enhanced by using a threefold approach, which consists of grain alignment,
doping, and optimization of the grain architecture. According to model
calculations, current densities of 4x10^6 A/cm2 can be achieved for an average
grain alignment of 10 degree at 77K. Based on this approach, a road to
competitive high-Tc cables is proposed.Comment: 3 pages, 5 figure
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