19,655 research outputs found
Application of digital analysis of MSS data to agro-environmental studies
There are no author-identified significant results in this report
The first high-amplitude delta Scuti star in an eclipsing binary system
We report the discovery of the first high-amplitude delta Scuti star in an
eclipsing binary, which we have designated UNSW-V-500. The system is an
Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag.
A best-fitting solution to the binary light curve and two radial velocity
curves is derived using the Wilson-Devinney code. We identify a late A spectral
type primary component of mass 1.49+/-0.02 M_sun and a late K spectral type
secondary of mass 0.33+/-0.02 M_sun, with an inclination of 86.5+/-1.0 degrees,
and a period of 5.3504751+/-0.0000006 d. A Fourier analysis of the residuals
from this solution is performed using PERIOD04 to investigate the delta Scuti
pulsations. We detect a single pulsation frequency of f_1 = 13.621+/-0.015 c/d,
and it appears this is the first overtone radial mode frequency. This system
provides the first opportunity to measure the dynamical mass for a star of this
variable type; previously, masses have been derived from stellar evolution and
pulsation models.Comment: 7 pages, 6 figures, 2 tables, for submission to MNRAS, v2: paper size
change, small typographical changes to abstrac
Multiangle static and dynamic light scattering in the intermediate scattering angle range
We describe a light scattering apparatus based on a novel optical scheme
covering the scattering angle range 0.5\dg \le \theta \le 25\dg, an
intermediate regime at the frontier between wide angle and small angle setups
that is difficult to access by existing instruments. Our apparatus uses
standard, readily available optomechanical components. Thanks to the use of a
charge-coupled device detector, both static and dynamic light scattering can be
performed simultaneously at several scattering angles. We demonstrate the
capabilities of our apparatus by measuring the scattering profile of a variety
of samples and the Brownian dynamics of a dilute colloidal suspension
Biomass and nutrient flux measurements on Holothuria atra populations on windward reef flats at Enewetak, Marshall Islands
Although it is reasonably well established that corals symbiotic with endozoic algae (the zooxanthellae) are capable of multitrophic (1) existence, we are still a long way away from evaluating the relative importance of the various trophic pathways (2). There is no question that zooplankton provide a source of materials and energy to corals, yet there is doubt whether zooplankton are plentiful enough to supply all the needs for these essentials (3). There appear to be alternate sources of supply. Sufficient energy is likely to be available to the symbiotic association by virtue of the photosynthetic capacity of the zooxanthellae (4); thus, energy wise, the effects of the limited quantities of available zooplankton may be obviated. But what of the balance of nutrient elements such as N and P?https://scholarworks.wm.edu/vimsbooks/1139/thumbnail.jp
The Utilization of Dissolved Free Amino Acids by Estuarine Microorganisms
The importance of bacteria in the cycling of carbon in the Pamlico River estuary was studied by measuring the rates of uptake of organic compounds. Our methods allowed analysis with the Michaelis-Menten kinetics equations, and both the rates of uptake of dissolved free amino acids (DFAA) and glucose as well as the percentage of carbon subsequently respired as CO2 were determined. In addition, the concentrations of the amino acids in the water were determined using ion exchange chromatography. Other tests included measurements of primary productivity and of the effects of the other amino acids in the water upon the uptake of one amino acid. (...
Thermal fatigue tests of a radiative heat shield panel for a hypersonic transport
A pair of corrugation stiffened, beaded skin Rene 41 heat shield panels were exposed to 20,000 thermal cycles between room temperature and 1450 F to evaluate the thermal fatigue response of Rene 41 metallic heat shields for hypersonic cruise aircraft applications. At the conclusion of the tests, the panels retained substantial structural integrity; however, there were cracks and excessive wear in the vicinity of fastener holes and there was an 80-percent loss in ductility of the skin. Shrinkage of the panel which caused the cracks and wear must be considered in design of panels for Thermal Protection Systems (TPS) applications
The Broadband Spectrum of Galaxy Clusters
We examine whether nonthermal protons energized during a cluster merger are
simultaneously responsible for the Coma cluster's diffuse radio flux (via
secondary decay) and the departure of its intra-cluster medium (ICM) from a
thermal profile via Coulomb collisions between the quasithermal electrons and
the hadrons. Rather than approximating the influence of nonthermal
proton/thermal electron collisions as extremely rare events which cause an
injection of nonthermal, power-law electrons (the `knock-on' approximation), we
self-consistently solve (to our knowledge, for the first time) the covariant
kinetic equations for the two populations. The electron population resulting
from these collisions is out of equilibrium, yet not a power law, and
importantly displays a higher bremsstrahlung radiative efficiency than a pure
power law. Observations with GLAST will test this model directly.Comment: Accepted for publication in Ap
Methods to Study Activity Dependent Protein Synthesis in Autism Spectrum Disorder
It is estimated by the World Health Organization that 1 in 100 children have autism spectrum disorder (ASD), a condition characterized by neurological differences that may impact a person’s learning or behavior. Clinically, ASD symptoms are alleviated with behavioral or pharmacological therapies, however, not all patients respond to these interventions. Deep brain stimulation (DBS) is a promising treatment of Parkinson’s disease that could also be effective in treating ASD. SynGAP1 is a protein involved in neuronal action that is crucial for regulating synaptic plasticity. Mutations in the SYNGAP1 gene causing haploinsufficiency can result in the manifestation of ASD symptoms. This study aims at gathering information on the potential of using a Syngap1+/- mouse model to determine whether DBS can counter neurological differences between mice with haploinsufficiency and wild type littermates. Histology slides were analyzed for lesioning from previous surgeries performed in which electrodes were placed for DBS. To gain baseline data before DBS, behavioral tests were conducted on both male and female wild type and Syngap1+/- mice to understand differences. To correlate behavioral results with protein synthesis, labeling of newly synthesized proteins was optimized using azidohomoalanine. Inspection of histology slides showed no evidence of brain lesioning in mice that were to have undergone DBS. Behavioral results revealed increased hyperactivity in mice with haploinsufficiency. Additionally, SDS-PAGE analysis of azidohomoalanine injections revealed more injections administered on subsequent days provides optimal proteomic labeling. With this information, further research can be conducted in which DBS is performed followed by behavioral studies and proteomic analysis
X-ray bright points and He I lambda 10830 dark points
Using near-simultaneous full disk Solar X-ray images and He I 10830 lambda, spectroheliograms from three recent rocket flights, dark points identified on the He I maps were compared with X-ray bright points identified on the X-ray images. It was found that for the largest and most obvious features there is a strong correlation: most He I dark points correspond to X-ray bright points. However, about 2/3 of the X-ray bright points were not identified on the basis of the helium data alone. Once an X-ray feature is identified it is almost always possible to find an underlying dark patch of enhanced He I absorption which, however, would not a priori have been selected as a dark point. Therefore, the He I dark points, using current selection criteria, cannot be used as a one-to-one proxy for the X-ray data. He I dark points do, however, identify the locations of the stronger X-ray bright points
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