Pancharatnam-Berry phase in condensate of indirect excitons

We report on the observation of the Pancharatnam-Berry phase in a condensate of indirect excitons (IXs) in a GaAs coupled quantum well structure. The Pancharatnam-Berry phase leads to phase shifts of interference fringes in IX interference patterns. Correlations are found between the phase shifts, polarization pattern of IX emission, and onset of IX spontaneous coherence. The Pancharatnam-Berry phase is acquired due to coherent spin precession in IX condensate. The effect of the Pancharatnam-Berry phase on the IX phase pattern is described in terms of an associated momentum.Comment: 6 pages, 5 figures + 2 pages supplemental material, 3 supplemental figure

Collection of indirect excitons in a diamond-shaped electrostatic trap

We report on the principle and realization of a new trap for excitons -- the diamond electrostatic trap -- which uses a single electrode to create a confining potential for excitons. We also create elevated diamond traps which permit evaporative cooling of the exciton gas. We observe collection of excitons towards the trap center with increasing exciton density. This effect is due to screening of disorder in the trap by the excitons. As a result, the diamond trap behaves as a smooth parabolic potential which realizes a cold and dense exciton gas at the trap center.Comment: 4 Pages, 5 figure

Transport of Indirect Excitons in a Potential Energy Gradient

We realized a potential energy gradient - a ramp - for indirect excitons using a shaped electrode at constant voltage. We studied transport of indirect excitons along the ramp and observed that the exciton transport distance increases with increasing density and temperature.Comment: 4 pages, 3 figure

Progress in the molecular biology of inherited bleeding disorders

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73391/1/j.1365-2516.2008.01718.x.pd

Optical followup of galaxy clusters detected by the South Pole Telescope

The South Pole Telescope (SPT) is a 10 meter telescope operating at mm wavelengths. It has recently completed a three-band survey covering 2500 sq. degrees. One of the survey's main goals is to detect galaxy clusters using Sunyaev-Zeldovich effect and use these clusters for a variety of cosmological and astrophysical studies such as the dark energy equation of state, the primordial non-gaussianity and the evolution of galaxy populations. Since 2005, we have been engaged in a comprehensive optical and near-infrared followup program (at wavelengths between 0.4 and 5 {\mu}m) to image high-significance SPT clusters, to measure their photometric redshifts, and to estimate the contamination rate of the candidate lists. These clusters are then used for various cosmological and astrophysical studies.Comment: For TAUP 2011 proceeding

Complications of nephrogenic systemic fibrosis following repeated exposure to gadolinium in a man with hypothyroidism: a case report

Introduction Nephrogenic systemic fibrosis is a condition that has recently been recognized in patients with chronic renal disease and is associated with use of gadolinium-based contrast agents of ubiquitous use in magnetic resonance imaging scans. The condition is believed to arise through inadequate renal clearance of the gadolinium-based contrast agents, resulting in bodily deposition of the gadolinium; this is most widely recognized in the skin, but also occurs in other tissues. Case presentation We report the case of a 52-year-old Caucasian man with hypothyroidism and chronic renal disease who developed nephrogenic systemic fibrosis upon repeated exposure to gadolinium, and who presented with a subsequent malabsorption of levothyroxine. This malabsorption resolved only partially upon amelioration of other conditions that might contribute to malabsorption, including edema and infectious diarrhea. The presence of gadolinium was quantified in specimens from his gastrointestinal tract. Our patient otherwise demonstrated adequate gastrointestinal nutritive absorption, objectively shown by normal albumin levels, resolution of diarrhea, and maintenance of his bodily weight. Conclusions Our observations suggest that nephrogenic systemic fibrosis can also affect tissue of the gastrointestinal tract, potentially contributing to partial malabsorption of levothyroxine in patients with hypothyroidism

Spin Texture in a Cold Exciton Gas

We report on the observation of a spin texture in a cold exciton gas in a GaAs/AlGaAs coupled quantum well structure. The spin texture is observed around the exciton rings. The observed phenomena include: a ring of linear polarization, a vortex of linear polarization with polarization perpendicular to the radial direction, an anisotropy in the exciton flux, a skew of the exciton fluxes in orthogonal circular polarizations and a corresponding four-leaf pattern of circular polarization, a periodic spin texture, and extended exciton coherence in the region of the polarization vortex. The data indicate a transport regime where the spin polarization is locked to the direction of particle propagation and scattering is suppressed.Comment: version 2 contains updated supplementary materia

A viable mouse model of factor X deficiency provides evidence for maternal transfer of factor X

Background:Activated factor X (FXa) is a vitamin K-dependent serine protease that plays a pivotal role in blood coagulation by converting prothrombin to thrombin. There are no reports of humans with complete deficiency of FX, and knockout of murine F10 is embryonic or perinatal lethal. Objective:We sought to generate a viable mouse model of FX deficiency. Methods:We used a socket-targeting construct to generate F10-knockout mice by eliminating F10 exon 8 (knockout allele termed F10tm1Ccmt, abbreviated as ‘−’; wild-type ‘+’), and a plug-targeting construct to generate mice expressing a FX variant with normal antigen levels but low levels of FX activity [4–9% normal in humans carrying the defect, Pro343→Ser, termed FX Friuli (mutant allele termed F10tm2Ccmt, abbreviated as F)]. Results:F10 knockout mice exhibited embryonic or perinatal lethality. In contrast, homozygous Friuli mice [F10 (F/F)] had FX activity levels of ∼5.5% (sufficient to rescue both embryonic and perinatal lethality), but developed age-dependent iron deposition and cardiac fibrosis. Interestingly, F10 (−/F) mice with FX activity levels of 1–3% also showed complete rescue of lethality. Further study of this model provides evidence supporting a role of maternal FX transfer in the embryonic survival. Conclusions:We demonstrate that, while complete absence of FX is incompatible with murine survival, minimal FX activity as low as 1–3% is sufficient to rescue the lethal phenotype. This viable low-FX mouse model will facilitate the development of FX-directed therapies as well as investigation of the FX role in embryonic development