Evaluation of Photodiode Arrays for Use in Rocket Plume Monitoring and Diagnostics

The spectroscopic analysis of plume emissions is a non-intrusive method which has been used to check for fatigue and possible damage throughout the pumps and other mechanisms in a rocket motor or engine. These components are made of various alloys. Knowing the composition of the alloys and for which parts they are used, one can potentially determine from the emissions in the plume which component is failing. Currently, Optical Multichannel Analyzer systems are being used which utilize charge coupled devices, cost tens of thousands of dollars, are somewhat delicate, and usually require cooling. We have developed two rugged instruments using less expensive linear photodiode arrays as detectors. A high resolution system was used to detect atomic emission lines while a low resolution system was used to detect molecular emission bands. We have also written data acquisition software and built electronic circuits to control the arrays and collect data. While NASA has used similar systems for characterization of the Space Shuttle Main Engine, the emissions from other rocket systems have not been surveyed as well. The two instruments described will be utilized to study hybrid rocket emissions at the UALR hybrid rocket facility

Decade-Scale Trend in Sea Water Salinity Revealed Through δ18O Analysis of Montastraea annularis Annual Growth Bands

Stable oxygen isotope ratios (δ18O) of coral skeletons are influenced by ambient water temperature and by the oxygen isotope ratio in the surrounding sea water, which, in turn, is linked to evaporation (salinity) and precipitation. To investigate this relationship more thoroughly, we collected hourly temperature data from the Hen and Chickens Reef in the Florida Keys between 1975 and 1988 and compared them to the δ18O of Montastraea annularis skeleton that grew during the same interval. To ensure that we obtained the correct oxygen isotopic range in the skeleton we typically sampled the coral at a resolution of 20–30 samples in 1 year; in 1 year we sampled the coral at a resolution of 70 samples·year−1. Despite our high-resolution sampling, we were unable to obtain the full temperature-induced δ18O range in the skeleton. Our data suggest that, during the summer, evaporation causes isotopic enrichment in the water, partially masking the temperature-induced signal. Our data also show that oxygen isotopic composition of seawater at the reef has increased since 1981. This increase indicates that salinity has increased slightly during the past decade, perhaps as a result of increased evaporation in waters of Florida Bay and the Keys. This phenomenon is probably not caused by a decrease in the outflow of freshwater into Florida Bay from the Everglades but may be related to the measured deficit in precipitation that has occurred over the past decade

Epidemiology of Cigarette and Smokeless Tobacco Use among South Asian Immigrants in the Northeastern United States

As the most preventable cause of death in the world today, understanding tobacco use among one of the fastest growing ethnic/racial groups is warranted. We explore cigarette and smokeless tobacco (SLT) use among South Asians in NJ and the Northeast using the Tobacco Use Supplement to the Current Population Survey. Overall, tobacco use rates among South Asians were similar or lower than the population. However, in NJ, South Asian males had the highest SLT rate (2.7%) and in the Northeast, White (AOR = 5.8, 95%  CI = 3.7–9.4) and South Asian males (AOR = 4.0, 95%  CI = 1.5–10.6) had significantly higher odds of current SLT use relative to non-White males. Tobacco use among South Asians was not homogeneous; Pakistanis are overrepresented among cigarette smokers while Indians are overrepresented among SLT users. Given the differential tobacco use among and within South Asian, disaggregating data to understand tobacco use behaviors is necessary to develop effective interventions for tobacco cessation

One-and-a-half quantum de Finetti theorems

We prove a new kind of quantum de Finetti theorem for representations of the unitary group U(d). Consider a pure state that lies in the irreducible representation U_{mu+nu} for Young diagrams mu and nu. U_{mu+nu} is contained in the tensor product of U_mu and U_nu; let xi be the state obtained by tracing out U_nu. We show that xi is close to a convex combination of states Uv, where U is in U(d) and v is the highest weight vector in U_mu. When U_{mu+nu} is the symmetric representation, this yields the conventional quantum de Finetti theorem for symmetric states, and our method of proof gives near-optimal bounds for the approximation of xi by a convex combination of product states. For the class of symmetric Werner states, we give a second de Finetti-style theorem (our 'half' theorem); the de Finetti-approximation in this case takes a particularly simple form, involving only product states with a fixed spectrum. Our proof uses purely group theoretic methods, and makes a link with the shifted Schur functions. It also provides some useful examples, and gives some insight into the structure of the set of convex combinations of product states.Comment: 14 pages, 3 figures, v4: minor additions (including figures), published versio

The maize brown midrib6 (bm6) mutation encodes a functional GTP Cyclohydrolase1

Brown midrib mutations in maize (Zea mays L.) and sorghum (Sorghum bicolor L.) alter lignin composition and enhance cell wall digestibility. These mutations are prime candidates for silage breeding. Six brown midrib mutants are currently known, brown midrib1 (bm1) to brown midrib6 (bm6). The bm1 and bm3 mutations are being used commercially for silage. The underlying genes responsible for five of the six bm mutations in maize (bm1, bm2, bm3, bm4, and bm5) are known. Chen and co-workers (2012) characterized the bm6 mutation, demonstratingthat bm6 increases cell wall digestibility and physically mapped bm6 within a 180 kilobase region on chromosome 2. The present investigation utilized map-based cloning to identify the candidate gene responsible for the bm6 phenotype as GTP Cyclohydrolase1 (GCH1) and validated the candidate gene through reverse genetics. Orthologs of bm6 include at least one paralogous gene in maize on chromosome 10 and various homologs in other grasses and dicots. The discovery that GCH1 is  responsible for the maize bm6 phenotype suggests that GCH1 plays a role in the tetrahydrofolate biosynthetic process

Excited states of linear polyenes

We present density matrix renormalisation group calculations of the Pariser- Parr-Pople-Peierls model of linear polyenes within the adiabatic approximation. We calculate the vertical and relaxed transition energies, and relaxed geometries for various excitations on long chains. The triplet (3Bu+) and even- parity singlet (2Ag+) states have a 2-soliton and 4-soliton form, respectively, both with large relaxation energies. The dipole-allowed (1Bu-) state forms an exciton-polaron and has a very small relaxation energy. The relaxed energy of the 2Ag+ state lies below that of the 1Bu- state. We observe an attraction between the soliton-antisoliton pairs in the 2Ag+ state. The calculated excitation energies agree well with the observed values for polyene oligomers; the agreement with polyacetylene thin films is less good, and we comment on the possible sources of the discrepencies. The photoinduced absorption is interpreted. The spin-spin correlation function shows that the unpaired spins coincide with the geometrical soliton positions. We study the roles of electron-electron interactions and electron-lattice coupling in determining the excitation energies and soliton structures. The electronic interactions play the key role in determining the ground state dimerisation and the excited state transition energies.Comment: LaTeX, 15 pages, 9 figure

Measurement of the electron electric dipole moment using YbF molecules

The most sensitive measurements of the electron electric dipole moment d_e have previously been made using heavy atoms. Heavy polar molecules offer a greater sensitivity to d_e because the interaction energy to be measured is typically 10^3 times larger than in a heavy atom. We report the first measurement of this kind, for which we have used the molecule YbF. Together, the large interaction energy and the strong tensor polarizability of the molecule make our experiment essentially free of the systematic errors that currently limit d_e measurements in atoms. Our first result d_e = (- 0.2 \pm 3.2) x 10^-26 e.cm is less sensitive than the best atom measurement, but is limited only by counting statistics and demonstrates the power of the method.Comment: 4 pages, 4 figures. v2. Minor corrections and clarifications made in response to referee comment

Placebo response in binge eating disorder

Objective: Placebo response in studies of binge eating disorder (BED) has raised concern about its diagnostic stability. The aims of this study were (1) to compare placebo responders (PRs) with nonresponders (NRs); (2) to investigate the course of BED following placebo response; and (3) to examine attributions regarding placebo response. Method: The baseline placebo run-in phase (BL) was part of a RCT investigating sibutramine hydrochloride for BED; it included 451 participants, ages 19–63, diagnosed with BED. Follow-up (FU) included 33 PRs. Results: In this study, 32.6% of participants responded to placebo (PRs = 147; NRs = 304). PRs exhibited significantly less symptom severity. At FU (n = 33), many PRs reported continued symptoms. Conclusion: PRs exhibited significantly less severe pathology than NRs. Placebo response in BED may transitory or incomplete. The results of this study suggest variable stability in the BED diagnosis