ENTROPY-BASED ESTIMATION AND INFERENCE IN BINARY RESPONSE MODELS UNDER ENDOGENEITY

This paper considers estimation and inference for the binary response model in the case where endogenous variables are included as arguments of the unknown link function. Semiparametric estimators are proposed that avoid the parametric assumptions underlying the likelihood approach as well as the loss of precision when using nonparametric estimation. Suggestions are made for how the utility maximization decision model can be altered to permit attributes to vary across alternatives.Research Methods/ Statistical Methods,

WASP-12b as a prolate, inflated and disrupting planet from tidal dissipation

The class of exotic Jupiter-mass planets that orbit very close to their parent stars were not explicitly expected before their discovery. The recently found transiting planet WASP-12b has a mass Mp = 1.4(+/-0.1) Jupiter masses (MJ), a mean orbital distance of only 3.1 stellar radii (meaning it is subject to intense tidal forces), and a period of 1.1 days. Its radius 1.79(+/- 0.09) RJ is unexpectedly large and its orbital eccentricity 0.049(+/-0:015) is even more surprising as such close orbits are in general quickly circularized. Here we report an analysis of its properties, which reveals that the planet is losing mass to its host star at a rate ~ 10^-7 MJ yr^-1. The planets surface is distorted by the stars gravity and the light curve produced by its prolate shape will differ by about ten per cent from that of a spherical planet. We conclude that dissipation of the stars tidal perturbation in the planets convective envelope provides the energy source for its large volume. We predict up to 10mJy CO band-head (2.292 micron) emission from a tenuous disk around the host star, made up of tidally stripped planetary gas. It may also contain a detectable resonant super-Earth, as a hypothetical perturber that continually stirs up WASP-12b's eccentricity.Comment: Accepted to Nature, 14 pages, 1 figur

Field measurements of the fluid and sediment-dynamic environment of a benthic deposit feeder

Field measurements of flow and sediment transport at an intertidal site in False Bay, San Juan Island, Washington, U.S.A., revealed an environment dominated by wind wave-generated oscillatory flows and discrete sediment suspension events. Time series data showed that within a few tenths of a second, near-bottom suspended sediment concentrations can rise to 10 g l–1. These rapid erosion events are correlated with peak wave velocities and are followed by a more gradual (tens of seconds) decline in sediment concentration due to settling and advection. Large suspension events mixed detect able quantities of sediment to a height of 20 cm above the bottom. Flow and sediment transport rates are controlled by local weather and vary on time scales ranging from that of individual waves to that of atmospheric storm systems and seasonal changes in weather patterns. Advection of sediment can exceed individual deposit feeding rates by a factor of 103–104. An empirical relationship developed from weather records, together with previously published observations of detrital transport, suggests that sediment transport is rarely small enough in magnitude to be ignored as a source of food particles for surface deposit- and suspension-feeding spionid polychaetes like Pseudopolydora kempi japonica.

Growth of Intermediate-Mass Black Holes in Globular Clusters

We present results of numerical simulations of sequences of binary-single scattering events of black holes in dense stellar environments. The simulations cover a wide range of mass ratios from equal mass objects to 1000:10:10 solar masses and compare purely Newtonian simulations to simulations in which Newtonian encounters are interspersed with gravitational wave emission from the binary. In both cases, the sequence is terminated when the binary's merger time due to gravitational radiation is less than the arrival time of the next interloper. We find that black hole binaries typically merge with a very high eccentricity (0.93 < e < 0.95 pure Newtonian; 0.85 < e < 0.90 with gravitational wave emission) and that adding gravitational wave emission decreases the time to harden a binary until merger by ~ 30% to 40%. We discuss the implications of this work for the formation of intermediate-mass black holes and gravitational wave detection.Comment: 28 pages including 9 figures, submitted to Ap

Fluid flow and suspended particulates as determinants of polychaete feeding behavior

We examined the interactive effects of fluid flow, bed characteristics and suspended load on the feeding behavior of four species of marine polychaetes. Two species of obligate deposit feeders (Marenzelleria viridis and Ampharete parvidentata) and two species of palp-coiling facultative suspension feeders (Spiochaetopterus oculatus and Spio setosa) were exposed to flow and sediment-bed treatments that served to decouple fluid flow and particle flux. We employed low (no particle transport), medium (transport of flocs only) and high (transport of sand) flow speeds in factorial treatments of natural sediment, winnowed bed (flocs removed), armored bed (no sand transport at high flows), and armored bed plus fines (flocs added). For each species, worms were exposed to an increasing (low, medium and high) and then decreasing (high, medium and low) flow leg for each bed treatment. We recorded visual observations of animal behavior of the four polychaete species. We found little systematic response to flow and bed differences in the two obligate deposit feeders. When fine material was present, one of the two species exhibited higher variability in time spent deposit feeding, possibly responding to small-scale depositional pockets enriched with fine particles and organic matter. For both facultative suspension feeders, there was an increase in time spent suspension feeding with increasing flow and suspended particle concentrations. Percent suspension feeding was also greater on the decreasing flow legs in treatments with fine material available for suspension. Exploratory analyses of the data reveal a direct relationship between time spent suspension feeding and the flux of suspended high quality organic matter. For both species, compositional parameters of particulate nitrogen and enzymatically available amino acid concentrations were the best correlates of suspension feeding behavior

Heterotopic gray matter in white matter in a 62 year old

"Heterotopia" describes normal cells in an abnormal location, and in the context of neurobiology, usually refers to neurons or gray matter in the leptomeninges or in periventricular or subcortical white matter, ("Gray Matter Heterotopia"). While once thought to be quite rare, the widespread MRI availability allowed increased recognition of these malformations. Clinically, gray matter heterotopias usually manifest as seizures in the first and second decades of life and may have associated motor and cognitive developmental disturbances. We report a patient with no known prior neurologic history, who developed seizures at the age of 62, which were subsequently determined to be from a subcortical gray matter heterotopia. The patient presented to an outside hospital with episodic confusion thought to represent partial seizures, and also numbness in her left foot, leg, and arm. MRI revealed a thickened corpus callosum and abnormal signal extending into the right cingulate gyrus white matter with an infiltrative appearance suggestive of a glioma or gliomatosis. Stereotactic biopsy demonstrated white matter containing irregular islands of synaptophysin-immunopositive gray matter within which there were large dysplastic neurons. This established a diagnosis of ectopic gray matter in the subcortical white matter. To our knowledge, this is the oldest age at which a person with this congenital condition has experienced onset of related symptoms