Improved Skin Friction Interferometer

An improved system for measuring aerodynamic skin friction which uses a dual-laser-beam oil-film interferometer was developed. Improvements in the optical hardware provided equal signal characteristics for each beam and reduced the cost and complexity of the system by replacing polarization rotation by a mirrored prism for separation of the two signals. An automated, objective, data-reduction procedure was implemented to eliminate tedious manual manipulation of the interferometry data records. The present system was intended for use in two-dimensional, incompressible flows over a smooth, level surface without pressure gradient, but the improvements discussed are not limited to this application

The alpha1 subunit of the GABA(A) receptor modulates fear learning and plasticity in the lateral amygdala.

Synaptic plasticity in the amygdala is essential for emotional learning. Fear conditioning, for example, depends on changes in excitatory transmission that occur following NMDA receptor activation and AMPA receptor modification in this region. The role of these and other glutamatergic mechanisms have been studied extensively in this circuit while relatively little is known about the contribution of inhibitory transmission. The current experiments addressed this issue by examining the role of the GABA(A) receptor subunit alpha1 in fear learning and plasticity. We first confirmed previous findings that the alpha1 subunit is highly expressed in the lateral nucleus of the amygdala. Consistent with this observation, genetic deletion of this subunit selectively enhanced plasticity in the lateral amygdala and increased auditory fear conditioning. Mice with selective deletion of alpha1 in excitatory cells did not exhibit enhanced learning. Finally, infusion of a alpha1 receptor antagonist into the lateral amygdala selectively impaired auditory fear learning. Together, these results suggest that inhibitory transmission mediated by alpha1-containing GABA(A) receptors plays a critical role in amygdala plasticity and fear learning

Coarse Marbled Beef is Juicier and More Flavorful Than Fine or Medium Marbled Beef

Beef palatability and eating experience is driven primarily by U.S. Department of Agriculture quality grade and marbling levels. Beef USDA quality grade consists of both marbling levels and maturity. Conventionally, marbling texture has not been a consideration of quality grades. Currently, only one study has assessed the effects of marbling texture on beef palatability. Despite this, preferences for fine or medium marbling exist with both packers and retailers, as approximately 75% of branded beef programs under the supervision of USDA-AMS require fine or medium textured marbling, which equates to losses of premiums for packers and producers (USDA, 2016). The objective of the study was to evaluate the effects of marbling texture on trained sensory panel ratings of beef strip loin steaks of varying USDA quality grades and marbling textures

Marbling Texture Does Not Affect Consumer Preference of Beef Strip Loin Steaks

In the beef industry, U.S. Department of Agriculture quality grades and marbling levels have long been associated with beef palatability and eating experience. Marbling score and maturity are the two major components of USDA quality grade. Traditionally, marbling texture has not been considered a factor of marbling score; however, there are often discernments at both the packer and retail level, as more than 75% of branded beef programs supervised by USDA-AMS have a specification of fine or medium textured marbling (USDA, 2015). Additionally, in some cases, fine and medium textured steaks are graded higher than their coarse counterparts, which results in a loss of possible premiums for producers and packers. There is very little research evaluating marbling texture and its effect on palatability and eating experience

Gravitational Radiation from Nonaxisymmetric Instability in a Rotating Star

We present the first calculations of the gravitational radiation produced by nonaxisymmetric dynamical instability in a rapidly rotating compact star. The star deforms into a bar shape, shedding $\sim 4\%$ of its mass and $\sim 17\%$ of its angular momentum. The gravitational radiation is calculated in the quadrupole approximation. For a mass $M \sim 1.4$ M$_{\odot}$ and radius $R \sim 10$ km, the gravitational waves have frequency $\sim 4$ kHz and amplitude $h \sim 2 \times 10^{-22}$ at the distance of the Virgo Cluster. They carry off energy $\Delta E/M \sim 0.1\%$ and radiate angular momentum $\Delta J/J \sim 0.7\%$.Comment: 16 pages, LaTeX with REVTEX macros, reprints available - send mailing address to [email protected]. Published: PRL 72, 1314 (1994

An improved short-lived fluorescent protein transcriptional reporter for S. cerevisiae.

Ideal reporter genes for temporal transcription programmes have short half-lives that restrict their detection to the window in which their transcripts are present and translated. In an effort to meet this criterion for reporters of transcription in individual living cells, we adapted the ubiquitin fusion strategy for programmable N-end rule degradation to generate an N-degron version of green fluorescent protein (GFP) with a half-life of ~7 min. The GFP variant we used here (designated GFP*) has excellent fluorescence brightness and maturation properties, which make the destabilized reporter well suited for tracking the induction and attenuation kinetics of gene expression in living cells. These attributes are illustrated by its ability to track galactose- and pheromone-induced transcription in S. cerevisiae. We further show that the fluorescence measurements using the short-lived N-degron GFP* reporter gene accurately predict the transient mRNA profile of the prototypical pheromone-induced FUS1 gene. Copyright © 2012 John Wiley & Sons, Ltd

Gravitational Radiation from Rotational Instabilities in Compact Stellar Cores with Stiff Equations of State

We carry out 3-D numerical simulations of the dynamical instability in rapidly rotating stars initially modeled as polytropes with n = 1.5, 1.0, and 0.5. The calculations are done with a SPH code using Newtonian gravity, and the gravitational radiation is calculated in the quadrupole limit. All models develop the global m=2 bar mode, with mass and angular momentum being shed from the ends of the bar in two trailing spiral arms. The models then undergo successive episodes of core recontraction and spiral arm ejection, with the number of these episodes increasing as n decreases: this results in longer-lived gravitational wave signals for stiffer models. This instability may operate in a stellar core that has expended its nuclear fuel and is prevented from further collapse due to centrifugal forces. The actual values of the gravitational radiation amplitudes and frequencies depend sensitively on the radius of the star R_{eq} at which the instability develops.Comment: 39 pages, uses Latex 2.09. To be published in the Dec. 15, 1996 issue of Physical Review D. 21 figures (bitmapped). Originals available in compressed Postscript format at ftp://zonker.drexel.edu/papers/bars

Comparison of advanced gravitational-wave detectors

We compare two advanced designs for gravitational-wave antennas in terms of their ability to detect two possible gravitational wave sources. Spherical, resonant mass antennas and interferometers incorporating resonant sideband extraction (RSE) were modeled using experimentally measurable parameters. The signal-to-noise ratio of each detector for a binary neutron star system and a rapidly rotating stellar core were calculated. For a range of plausible parameters we found that the advanced LIGO interferometer incorporating RSE gave higher signal-to-noise ratios than a spherical detector resonant at the same frequency for both sources. Spheres were found to be sensitive to these sources at distances beyond our galaxy. Interferometers were sensitive to these sources at far enough distances that several events per year would be expected