A Search for Hydroxylamine (NH_2OH) toward Select Astronomical Sources

Observations of 14 rotational transitions of hydroxylamine (NH_2OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH_2OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored

Synchrotron and Inverse Compton Constraints on Lorentz Violations for Electrons

We present a method for constraining Lorentz violation in the electron sector, based on observations of the photons emitted by high-energy astrophysical sources. The most important Lorentz-violating operators at the relevant energies are parameterized by a tensor c^{nu mu) with nine independent components. If c is nonvanishing, then there may be either a maximum electron velocity less than the speed of light or a maximum energy for subluminal electrons; both these quantities will generally depend on the direction of an electron's motion. From synchrotron radiation, we may infer a lower bound on the maximum velocity, and from inverse Compton emission, a lower bound on the maximum subluminal energy. With observational data for both these types of emission from multiple celestial sources, we may then place bounds on all nine of the coefficients that make up c. The most stringent bound, on a certain combination of the coefficients, is at the 6 x 10^(-20) level, and bounds on the coefficients individually range from the 7 x 10^(-15) level to the 2 x 10^(-17) level. For most of the coefficients, these are the most precise bounds available, and with newly available data, we can already improve over previous bounds obtained by the same methods.Comment: 28 page

The search for novel analgesics: re-examining spinal cord circuits with new tools

In this perspective, we propose the absence of detailed information regarding spinal cord circuits that process sensory information remains a major barrier to advancing analgesia. We highlight recent advances showing that functionally discrete populations of neurons in the spinal cord dorsal horn play distinct roles in processing sensory information. We then discuss new molecular, electrophysiological, and optogenetic techniques that can be employed to understand how dorsal horn circuits process tactile and nociceptive information. We believe this information can drive the development of entirely new classes of pharmacotherapies that target key elements in spinal circuits to selectively modify sensory function and blunt pain

Model Atmospheres for Irradiated Stars in pre-Cataclysmic Variables

Model atmospheres have been computed for M dwarfs that are strongly irradiated by nearby hot companions. A variety of primary and secondary spectral types are explored in addition to models specific to four known systems: GD 245, NN Ser, AA Dor, and UU Sge. This work demonstrates that a dramatic temperature inversion is possible on at least one hemisphere of an irradiated M dwarf and the emergent spectrum will be significantly different from an isolated M dwarf or a black body flux distribution. For the first time, synthetic spectra suitable for direct comparison to high-resolution observations of irradiated M dwarfs in non-mass transferring post-common envelope binaries are presented. The effects of departures from local thermodynamic equilibrium on the Balmer line profiles are also discussed.Comment: Accepted for publication in ApJ; 12 pages, 10 figure

Contingency power for small turboshaft engines using water injection into turbine cooling air

Because of one engine inoperative requirements, together with hot-gas reingestion and hot day, high altitude takeoff situations, power augmentation for multiengine rotorcraft has always been of critical interest. However, power augmentation using overtemperature at the turbine inlet will shorten turbine life unless a method of limiting thermal and mechanical stresses is found. A possible solution involves allowing the turbine inlet temperature to rise to augment power while injecting water into the turbine cooling air to limit hot-section metal temperatures. An experimental water injection device was installed in an engine and successfully tested. Although concern for unprotected subcomponents in the engine hot section prevented demonstration of the technique's maximum potential, it was still possible to demonstrate increases in power while maintaining nearly constant turbine rotor blade temperature

Pencil-Beam Surveys for Faint Trans-Neptunian Objects

We have conducted pencil-beam searches for outer solar system objects to a limiting magnitude of R ~ 26. Five new trans-neptunian objects were detected in these searches. Our combined data set provides an estimate of ~90 trans-neptunian objects per square degree brighter than ~ 25.9. This estimate is a factor of 3 above the expected number of objects based on an extrapolation of previous surveys with brighter limits, and appears consistent with the hypothesis of a single power-law luminosity function for the entire trans-neptunian region. Maximum likelihood fits to all self-consistent published surveys with published efficiency functions predicts a cumulative sky density Sigma(<R) obeying log10(Sigma) = 0.76(R-23.4) objects per square degree brighter than a given magnitude R.Comment: Accepted by AJ, 18 pages, including 6 figure

DNA-decorated graphene chemical sensors

Graphene is a true two dimensional material with exceptional electronic properties and enormous potential for practical applications. Graphene's promise as a chemical sensor material has been noted but there has been relatively little work on practical chemical sensing using graphene, and in particular how chemical functionalization may be used to sensitize graphene to chemical vapors. Here we show one route towards improving the ability of graphene to work as a chemical sensor by using single stranded DNA as a sensitizing agent. The resulting broad response devices show fast response times, complete and rapid recovery to baseline at room temperature, and discrimination between several similar vapor analytes.Comment: 7 pages, To appear in Applied Physics Letter

On the Moduli Space of SU(3) Seiberg-Witten Theory with Matter

We present a qualitative model of the Coulomb branch of the moduli space of low-energy effective N=2 SQCD with gauge group SU(3) and up to five flavours of massive matter. Overall, away from double cores, we find a situation broadly similar to the case with no matter, but with additional complexity due to the proliferation of extra BPS states. We also include a revised version of the pure SU(3) model which can accommodate just the orthodox weak coupling spectrum.Comment: 32 pages, 25 figures, uses JHEP.cls, added references, deleted joke

Tempo and intensity of pre-task music modulate neural activity during reactive task performance

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 The Authors.Research has shown that not only do young athletes purposively use music to manage their emotional state (Bishop, Karageorghis, & Loizou, 2007), but also that brief periods of music listening may facilitate their subsequent reactive performance (Bishop, Karageorghis, & Kinrade, 2009). We report an fMRI study in which young athletes lay in an MRI scanner and listened to a popular music track immediately prior to performance of a three-choice reaction time task; intensity and tempo were modified such that six excerpts (2 intensities × 3 tempi) were created. Neural activity was measured throughout. Faster tempi and higher intensity collectively yielded activation in structures integral to visual perception (inferior temporal gyrus), allocation of attention (cuneus, inferior parietal lobule, supramarginal gyrus), and motor control (putamen), during reactive performance. The implications for music listening as a pre-competition strategy in sport are discussed