Impact Assessment of Technologies That Mitigate Adverse Circumstances: The Case of Disease-Resistant Beans in Honduras

Constructing appropriate counterfactual scenarios is an ongoing challenge for impact assessment of agricultural research. Using farm-level survey data from Honduras, this paper adapts the Heckman two-step procedure to construct the counterfactual to resistant variety (RV) bean yields by predicting imputed traditional variety yields of RV users.Crop Production/Industries,

WIMP Dark Matter and the QCD Equation of State

Weakly Interacting Massive Particles (WIMPs) of mass m freeze out at a temperature T_f ~ m/25, i.e. in the range 400 MeV -- 40 GeV for a particle in the typical mass range 10 -- 1000 GeV. The WIMP relic density, which depends on the effective number of relativistic degrees of freedom at T_f, may be measured to better than 1% by Planck, warranting comparable theoretical precision. Recent theoretical and experimental advances in the understanding of high temperature QCD show that the quark gluon plasma departs significantly from ideal behaviour up to temperatures of several GeV, necessitating an improvement of the cosmological equation of state over those currently used. We discuss how this increases the relic density by approximately 1.5 -- 3.5% in benchmark mSUGRA models, with an uncertainly in the QCD corrections of 0.5 -- 1 %. We point out what further work is required to achieve a theoretical accuracy comparable with the expected observational precision, and speculate that the effective number of degrees of freedom at T_f may become measurable in the foreseeable future.Comment: 4pp, 2figs. More info including Matlab scripts used to generate equation of state curves at http://www.pact.cpes.sussex.ac.uk/arXiv/hep-ph/0501232

The Least Bittern

n/

Determination of some dominant parameters of the global dynamic sea surface topography from GEOS-3 altimetry

The 1977 altimetry data bank is analyzed for the geometrical shape of the sea surface expressed as surface spherical harmonics after referral to the higher reference model defined by GEM 9. The resulting determination is expressed as quasi-stationary dynamic SST. Solutions are obtained from different sets of long arcs in the GEOS-3 altimeter data bank as well as from sub-sets related to the September 1975 and March 1976 equinoxes assembled with a view to minimizing seasonal effects. The results are compared with equivalent parameters obtained from the hydrostatic analysis of sporadic temperature, pressure and salinity measurements of the oceans and the known major steady state current systems with comparable wavelengths. The most clearly defined parameter (the zonal harmonic of degree 2) is obtained with an uncertainty of + or - 6 cm. The preferred numerical value is smaller than the oceanographic value due to the effect of the correction for the permanent earth tide. Similar precision is achieved for the zonal harmonic of degree 3. The precision obtained for the fourth degree zonal harmonic reflects more closely the accuracy expected from the level of noise in the orbital solutions

Updating existing emotional memories involves the frontopolar/orbitofrontal cortex in ways that acquiring new emotional memories does not

In life, we must often learn new associations to people, places, or things we already know. The current fMRI study investigated the neural mechanisms underlying emotional memory updating. Nineteen participants first viewed negative and neutral pictures and learned associations between those pictures and other neutral stimuli, such as neutral objects and encoding tasks. This initial learning phase was followed by a memory updating phase, during which participants learned picture-location associations for old pictures (i.e., pictures previously associated with other neutral stimuli) and new pictures (i.e., pictures not seen in the first phase). There was greater frontopolar/orbito-frontal (OFC) activity when people learned picture–location associations for old negative pictures than for new negative pictures, but frontopolar OFC activity did not significantly differ during learning locations of old versus new neutral pictures. In addition, frontopolar activity was more negatively correlated with the amygdala when participants learned picture–location associations for old negative pictures than for new negative or old neutral pictures. Past studies revealed that the frontopolar OFC allows for updating the affective values of stimuli in reversal learning or extinction of conditioning [e.g., Izquierdo, A., & Murray, E. A. Opposing effects of amygdala and orbital PFC lesions on the extinction of instrumental responding in macaque monkeys. European Journal of Neuroscience, 22, 2341–2346, 2005]; our findings suggest that it plays a more general role in updating associations to emotional stimuli

Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS

We present predicted full-sky maps of submillimeter and microwave emission from the diffuse interstellar dust in the Galaxy. These maps are extrapolated from the 100 micron emission and 100/240 micron flux ratio maps that Schlegel, Finkbeiner, & Davis (1998; SFD98) generated from IRAS and COBE/DIRBE data. Results are presented for a number of physically plausible emissivity models. We find that no power law emissivity function fits the FIRAS data from 200 - 2100 GHz. In this paper we provide a formalism for a multi-component model for the dust emission. A two-component model with a mixture of silicate and carbon-dominated grains (motivated by Pollack et al., 1994}) provides a fit to an accuracy of about 15% to all the FIRAS data over the entire high-latitude sky. Small systematic differences are found between the atomic and molecular phases of the ISM. Our predictions for the thermal (vibrational) emission from Galactic dust at \nu < 3000 GHz are available for general use. These full-sky predictions can be made at the DIRBE resolution of 40' or at the higher resolution of 6.1 arcmin from the SFD98 DIRBE-corrected IRAS maps.Comment: 48 pages, AAS LaTeX, 6 figures, ApJ (accepted). Data described in the text, as well as 4 additional figures, are available at http://astro.berkeley.edu/dus

Experimental Assessment of Mortality and Hyperglycemia in Tiger Muskellunge Due to Stocking Stressors

Tiger muskellunge (the F1 hybrid of female muskellunge Esox masquinongy and male northern pike E.lucius) have survived poorly when stocked in reservoirs. To understand why, we quantified, in the laboratory, both mortality and plasma glucose responses to three common stocking stressors: dipnet handling, confinement, and temperature increase. No young-of-year hybrids died within 48 h when the temperature was abruptly increased 10C, and only 5% died when the temperature was increased 12C, but 98% died within 4 h when the temperature was increased 15C. Thus, we concluded that thermal stress is an important determinant of poststocking mortality. Mortalities in response to three multiple-stressor treatments--(1) handling and temperature increase, (2) handling, confinement at a fish density of 83 g/L, and temperature increase, and (3) handling, confinement at 135 g/L, and temperature increase--did not differ from each other or from mortality associated with a temperature increase alone. Thus, handling and moderate-density confinement during transport do not necessarily increase poststocking mortality of tiger muskellunge. Abrupt temperature increases of 12 and 15C increased peak plasma glucose concentrations significantly. Handling and confinement together caused a significant hyperglycemia both with and without a temperature increase. However, the relative magnitude of the hyperglycemia caused by individual handling and confinement stressors depended on the presence of a thermal stressor. Finally, we found that plasma glucose concentrations and mortality were not correlated. Although glucose is easily measured and sensitive to small changes in stress, it is not a good indicator of reduced survival and should not be used as such in studies intended to quantify stress-induced mortality.This research was supported in part by funds from the Federal Aid in Fish Restoration Project F-57-R. The Department of Zoology, The Ohio State University, and the Ohio Cooperative Fishery Research Unit also provided financial assistance, computer money, and equipment