Forecast Encompassing Tests and Probability Forecasts

We consider tests of forecast encompassing for probability forecasts, for both quadratic and logarithmic scoring rules. We propose test statistics for the null of forecast encompassing, present the limiting distributions of the test statistics, and investigate the impact of estimating the forecasting models’ parameters on these distributions. The small-sample performance of the various statistics is investigated, both in terms of small numbers of forecasts and model estimation sample sizes. Two empirical applications show the usefulness of the tests for the evaluation of recession probability forecasts from logit models with different leading indicators as explanatory variables, and for evaluating survey-based probability forecasts. Probability forecasts ; encompassing tests ; recession probabilities

Analysis of the \u3ci\u3eFlehmen\u3c/i\u3e Display in American Bison (\u3ci\u3eBison bison\u3c/i\u3e)

A tota1 of 873 Flehmen (lip curl) displays by bison (Bison bison) was recorded and statistically analyzed in relation to individual factors such as age and sex, and external factors such as wind speed, wind direction, temperature, humidity, and Flehmen stimulus to determine if differences between subgroups of individuals existed and if Flehmen was environmentally affected. The mean lip curl display duration for all individuals was 8.4 seconds. Statistical tests of Flehmen duration means grouped by Flehmen stimuli showed a significant difference (p \u3c 0.05). Lip curl duration means for males (8.3 sec.) and females (9.3 sec.), maturity classes , all age-classes, cow age-classes, and bull age-classes were significantly different (p \u3c 0.05). Because of a marked decrease of duration means for prime bulls, some relationship between Flehmen duration and sexual behavior of bulls was suggested. Windspeed, humidity, and temperature were determined to have little influence on lip curl duration. No significant correlation was found between lip curl direction and wind direction. Local variations of windspeed, wind direction, humidity, and temperature around the lip curling individual do not permit legitimate conclusions regarding their effect on Flehmen duration and direction

Airborne Particles in Museums

Presents one in a series of research activities aimed at a better understanding of the origin and fate of air pollution within the built environment

Herpetofauna of Sylamore Ranger District, Ozark National Forest, Arkansas: Preliminary Report

A survey of the amphibians and reptiles of the Sylamore Ranger District, Ozark National Forest, Arkansas, was conducted from May 1969 through May 1972. The district is composed of 170,000 acres and includes parts of Stone, Baxter, Marion, and Searcy Counties. A total of 533 specimens was collected during the study. An additional 72 specimens in the collections of Memphis State University and Arkansas State University were examined. Forty-nine species were recorded from the study area. These consisted of 8 salamanders, 12 frogs and toads, 4 turtles, 6 lizards, and 19 snakes. Two species collected during the study, Scaphiopus holbrooki and Rana sylatica, were not previously indicated by published range maps and range descriptions as occurring in north-central Arkansas

Multiplexing Stimulus Information through Rate and Temporal Codes in Primate Somatosensory Cortex

Our ability to perceive and discriminate textures relies on the transduction and processing of complex, high-frequency vibrations elicited in the fingertip as it is scanned across a surface. How naturalistic vibrations, and by extension texture, are encoded in the responses of neurons in primary somatosensory cortex (S1) is unknown. Combining single unit recordings in awake macaques and perceptual judgments obtained from human subjects, we show that vibratory amplitude is encoded in the strength of the response evoked in S1 neurons. In contrast, the frequency composition of the vibrations, up to 800 Hz, is not encoded in neuronal firing rates, but rather in the phase-locked responses of a subpopulation of neurons. Moreover, analysis of perceptual judgments suggests that spike timing not only conveys stimulus information but also shapes tactile perception. We conclude that information about the amplitude and frequency of natural vibrations is multiplexed at different time scales in S1, and encoded in the rate and temporal patterning of the response, respectively.</p

Analysis of the \u3ci\u3eFlehmen\u3c/i\u3e Display in American Bison (\u3ci\u3eBison bison\u3c/i\u3e)

A tota1 of 873 Flehmen (lip curl) displays by bison (Bison bison) was recorded and statistically analyzed in relation to individual factors such as age and sex, and external factors such as wind speed, wind direction, temperature, humidity, and Flehmen stimulus to determine if differences between subgroups of individuals existed and if Flehmen was environmentally affected. The mean lip curl display duration for all individuals was 8.4 seconds. Statistical tests of Flehmen duration means grouped by Flehmen stimuli showed a significant difference (p \u3c 0.05). Lip curl duration means for males (8.3 sec.) and females (9.3 sec.), maturity classes , all age-classes, cow age-classes, and bull age-classes were significantly different (p \u3c 0.05). Because of a marked decrease of duration means for prime bulls, some relationship between Flehmen duration and sexual behavior of bulls was suggested. Windspeed, humidity, and temperature were determined to have little influence on lip curl duration. No significant correlation was found between lip curl direction and wind direction. Local variations of windspeed, wind direction, humidity, and temperature around the lip curling individual do not permit legitimate conclusions regarding their effect on Flehmen duration and direction

Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots

The central-spin problem, in which an electron spin interacts with a nuclear spin bath, is a widely studied model of quantum decoherence. Dynamic nuclear polarization (DNP) occurs in central spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in spin-based quantum information processing for coherent electron and nuclear spin control. However, the mechanisms limiting DNP remain only partially understood. Here, we show that spin-orbit coupling quenches DNP in a GaAs double quantum dot, even though spin-orbit coupling in GaAs is weak. Using Landau-Zener sweeps, we measure the dependence of the electron spin-flip probability on the strength and direction of in-plane magnetic field, allowing us to distinguish effects of the spin-orbit and hyperfine interactions. To confirm our interpretation, we measure high-bandwidth correlations in the electron spin-flip probability and attain results consistent with a significant spin-orbit contribution. We observe that DNP is quenched when the spin-orbit component exceeds the hyperfine, in agreement with a theoretical model. Our results shed new light on the surprising competition between the spin-orbit and hyperfine interactions in central-spin systems.Comment: 5+12 pages, 9 figure