1,656 research outputs found
South Dakota Population, Housing and Farm Census Facts
Every day, school board officials, county agents, legislators, mayors, teachers, business men and women, and other community leaders make decisions that need to be based on reliable, up-to-date information. This report, an update of an earlier publication, provides social indicators- facts and trends which describe the social landscape-for each county in South Dakota
Between a Rock and a Hard Place: Managing Government Document Collections in a Digital World
An Oregon State University Libraries (OSUL) study group\u27s review of its current policies, practices, and costs provides an illustrative case study of the challenges in managing government documents during this period of transition from print to digital. In its exploration of more aggressive approaches to greatly increasing access to electronic collections and reducing the size of the print footprint, OSUL learned that the current requirements of the Federal Depository Library Program (FDLP) hamper such efforts. This case study provides background on prior internal studies, OSUL\u27s participation in a shared housing agreement, statistics on size and current usage of its government documents, and the costs to receive, process, and provide access to its document collection. It concludes with the recommendations for OSUL to be as proactive as it can be under the current FDLP rules and regulations while bringing projected costs to manage government documents more in line with higher priorities
Disentangling discrepancies between stellar evolution theory and sub-solar mass stars. The influence of the mixing length parameter for the UV Psc binary
Serious discrepancies have recently been observed between predictions of
stellar evolution models in the 0.7-1.1 M_sun mass range and accurately
measured properties of binary stars with components in this mass range. We
study one of these objects, the eclipsing binary UV Piscium, which is
particularly interesting because Popper (1997) derived age estimates for each
component which differed by more than a factor of two. In an attempt to solve
this significant discrepancy (a difference in age of 11 Gyr), we compute a
large grid of stellar evolution models with the CESAM code for each component.
By fixing the masses to their accurately determined values (relative error
smaller than 1% for both stars), we consider a wide range of possible
metallicities Z (0.01 to 0.05), and Helium content Y (0.25 to 0.34)
uncorrelated to Z. In addition, the mixing length parameter alpha_MLT is left
as another free parameter. We obtain a best fit in the T_eff-radius diagram for
a common chemical composition (Z, Y)=(0.012, 0.31), but a different MLT
parameter alpha_MLT_A = 0.95+-0.12(statistical)+0.30(systematic) and
alpha_MLT_B = 0.65+-0.07(stat)+0.10(syst). The apparent age discrepancy found
by Popper (1997) disappears with this solution, the components being coeval to
within 1%. This suggests that fixing alpha_MLT to its solar value (~1.6), a
common hypothesis assumed in most stellar evolutionary models, may not be
correct. Secondly, since alpha_MLT is smaller for the less massive component,
this suggests that the MLT parameter may decrease with stellar mass, showing
yet another shortcoming of the mixing length theory to explain stellar
convection. This trend needs further confirmation with other binary stars with
accurate data.Comment: 8 pages, accepted for publication in Astronomy & Astrophysic
Examining the Proteome of Drosophila Across Organism Lifespan
A survey of the proteome of Drosophila melanogaster at nine time points across the adult lifespan based on several mass-spectrometry-based techniques is presented. In total, there is evidence for 5902 unique peptides corresponding to 1699 different proteins. Of hundreds of relatively abundant components, many appear to be highly dynamic as the adult fly ages. Of those proteins that we observe changing with age, a majority, associated with metabolism, reproduction, and development, are downregulated. Other biological pathways such as defense response also show variable changes, where some proteins are down-regulated and others are up-regulated. The observed variations are compared with a report of genome-wide changes at the transcriptome level at different ages and the similarities and differences are presented
Multiwavelength optical observations of chromospherically active binary systems V. FF UMa (2RE J0933+624): a system with orbital period variation
This is the fifth paper in a series aimed at studying the chromospheres of
active binary systems using several optical spectroscopic indicators to obtain
or improve orbital solution and fundamental stellar parameters. We present here
the study of FF UMa (2RE J0933+624), a recently discovered, X-ray/EUV selected,
active binary with strong H_alpha emission. The objectives of this work are, to
find orbital solutions and define stellar parameters from precise radial
velocities and carry out an extensive study of the optical indicators of
chromospheric activity. We obtained high resolution echelle spectroscopic
observations during five observing runs from 1998 to 2004. We found radial
velocities by cross correlation with radial velocity standard stars to achieve
the best orbital solution. We also measured rotational velocity by
cross-correlation techniques and have studied the kinematic by galactic space-
velocity components (U, V, W) and Eggen criteria. Finally, we have determined
the chromospheric contribution in optical spectroscopic indicators, from Ca II
H & K to Ca II IRT lines, using the spectral subtraction technique. We have
found that this system presents an orbital period variation, higher than
previously detected in other RS CVn systems. We determined an improved orbital
solution, finding a circular orbit with a period of 3.274 days. We derived the
stellar parameters, confirming the subgiant nature of the primary component and
obtained rotational velocities (vsini), of 33.57 km/s and 32.38 km/s for the
primary and secondary components respectively. From our kinematic study, we can
deduce its membership to the Castor moving group. Finally, the activity study
has given us a better understanding of the possible mechanisms that produce the
orbital period variation.Comment: Latex file with 16 pages, 18 figures. Available at
http://www.ucm.es/info/Astrof/invest/actividad/actividad_pub.html Accepted
for publication in: Astronomy & Astrophysics (A&A
Orbital Solutions and Absolute Elements of the Short-Period Eclipsing Binary ES Librae
We have obtained new differential UBV photoelectric photometry and radial velocities of both components of the short-period eclipsing binary ES Lib. The system has a circular orbit with a period of 0.883040928 days and is seen at an inclination of 70.1°. With the Wilson-Devinney analysis program, we obtained a simultaneous solution of our photometric and spectroscopic observations that resulted in masses of M1 = 2.30 ± 0.03 Mâ and M2 = 0.97 ± 0.01 Mâ and the equal-volume radii of R1 = 2.69 ± 0.02 Râ and R2 = 1.83 ± 0.01 Râ for the primary and secondary, respectively. The secondary is oversized and overluminous for its mass. The effective temperatures of the primary and secondary are 8500 K (fixed) and 5774 ± 57 K, respectively. Despite the very large temperature difference, our photometric and spectroscopic data indicate that ES Lib is not semidetached but rather require it to be in an overcontact state, where both components exceed their critical Roche lobes. Given its nonthermal equilibrium state, if the overcontact solution correctly characterizes the system, the change from being semidetached to overcontact may have occurred recently. While the asymmetry of the light curves can be modeled well with a large, hot starspot or a large, cool one on the secondary component, we prefer the latter interpretation because cool spots are a typical feature on many contact binaries
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