21,082 research outputs found
Records of \u3ci\u3ePachybrachis\u3c/i\u3e in Illinois (Coleoptera: Chrysomelidae)
A list of the 20 species and subspecies of Pachybrachis contained in the collections of the Illinois Natural History Survey and Southern Illinois University, and the author\u27s personal collection, is presented, with recorded ecological data and county distribution records where known
Microsatellite and mitochondrial DNA analysis of Dungeness crab (Cancer magister) from California to northern British Columbia
Genetic variation was assessed using mitochondrial DNA and microsatellite markers from Dungeness crab between Iceberg Bay, British Columbia and San Luis Obispo, California. We found little pattern in overall genetic variation between sites in both marker types, and no significant Isolation by Distance model was fit. Site-specific variation in mitochondrial DNA haplotype frequencies suggested the existence of three subpopulations associated with the Alaska Current, the Puget Sound, and the California Current, but microsatellite DNA evidence did not support it. The ratio between sampling size for microsatellite markers and fragment size polymorphisms was low, limiting the resolving power of microsatellite DNA for neutral variation. Average pairwise Fst values for Iceberg Bay, British Columbia against all other populations was 0.156, as compared to the average pairwise Fst of 0.028 across all populations. In the southern region of the Puget Sound, Nisqually, Washington had a lower pairwise Fst of 0.044 but contained a large number of site-specific, unique mtDNA haplotypes. Additionally, we found 41 mtDNA haplotypes in 445 samples taken, with 23 of those haplotypes as singletons, suggesting that Dungeness crab went through a recent, post-bottleneck population expansion, likely associated with the most recent glacial relaxation
Contamination control program for the Cosmic Background Explorer: An overview
Each of the three state of the art instruments flown aboard NASA's Cosmic Background Explorer (COBE) were designed, fabricated, and integrated using unique contamination control procedures to ensure accurate characterization of the diffuse radiation in the universe. The most stringent surface level cleanliness specifications ever attempted by NASA were required by the Diffuse Infrared Background Experiment (DRIBE) which is located inside a liquid helium cooled dewar along with the Far Infrared Absolute Spectrophotometer (FIRAS). The DRIBE instrument required complex stray radiation suppression that defined a cold primary optical baffle system surface cleanliness level of 100A. The cleanliness levels of the cryogenic FIRAS instrument and the Differential Microwave Radiometer (DMR) which were positioned symmetrically around the dewar were less stringent ranging from 300 to 500A. To achieve these instrument cleanliness levels, the entire flight spacecraft was maintained at level 500A throughout each phase of development. The COBE contamination control program is described along with the difficulties experienced in maintaining the cleanliness quality of personnel and flight hardware throughout instrument assembly
Options for a lunar base surface architecture
The Planet Surface Systems Office at the NASA Johnson Space Center has participated in an analysis of the Space Exploration Initiative architectures described in the Synthesis Group report. This effort involves a Systems Engineering and Integration effort to define point designs for evolving lunar and Mars bases that support substantial science, exploration, and resource production objectives. The analysis addresses systems-level designs; element requirements and conceptual designs; assessments of precursor and technology needs; and overall programmatics and schedules. This paper focuses on the results of the study of the Space Resource Utilization Architecture. This architecture develops the capability to extract useful materials from the indigenous resources of the Moon and Mars. On the Moon, a substantial infrastructure is emplaced which can support a crew of up to twelve. Two major process lines are developed: one produces oxygen, ceramics, and metals; the other produces hydrogen, helium, and other volatiles. The Moon is also used for a simulation of a Mars mission. Significant science capabilities are established in conjunction with resource development. Exploration includes remote global surveys and piloted sorties of local and regional areas. Science accommodations include planetary science, astronomy, and biomedical research. Greenhouses are established to provide a substantial amount of food needs
Chapter 7 and Chapter 11 Bankruptcy Factors
In light of the Financial Accounting Standards Board’s August 2014 Accounting Standard Update on management Going Concern Statements, research using financial ratios to predict bankruptcy is more relevant than ever. Even though numerous research articles examine factors that predict bankruptcy, few make the distinction between the factors that affect Chapter 7 versus Chapter 11 bankruptcy. This work examines the factors that affect these two bankruptcy types (7 and 11) using the Securities and Exchange Commission data on 425 firms that filed for Chapter 7 or Chapter 11 bankruptcy. We tested our data using t-test, ordinary least squares (OLS), and logistic regression. Our results indicate that the asset turnover ratio and going concern statement are significant predictors of Chapter 7 versus Chapter 11 bankruptcy. We note the implications for auditors, corporate management, corporate creditors and investors, and the Financial Accounting Standards Board
OTV impacts and interactions
The possible impacts and interactions of the agency's planning activities for the Orbit Transfer Vehicle (OTV) that is tentatively scheduled for initial operational capability in the late 1990's are identified. In general, the various Mars missions require vehicles of significant size and performance far greater than that provided by any OTV configuration currently being seriously considered. Therefore, interactions and impacts on these current concepts are minimal. These impacts and interactions fall into categories of technologies, systems, and operations. Each category is addressed
Para hydrogen equilibration in the atmospheres of the outer planets
The thermodynamic behavior of the atmospheres of the Jovian planets is strongly dependent on the extent to which local thermal equilibration of the ortho and para states of molecular hydrogen is achieved. Voyager IRIS data from Jupiter imply substantial departures of the para hydrogen fraction from equilibrium in the upper troposphere at low latitudes, but with values approaching equilibrium at higher latitudes. Data from Saturn are less sensitive to the orth-para ratio, but suggest para hydrogen fractions near the equilibrium value. Above approximately the 200 K temperature level, para hydrogen conversion can enhance the efficiency of convection, resulting in a substantial increase in overturning times on all of the outer planets. Currently available data cannot definitively establish the ortho-para ratios in the atmospheres of Uranus and Neptune, but suggest values closer to local equilibrium than to the 3.1 normal ratio. Modeling of sub-millimeter wavelength measurements of these planets suggest thermal structures with frozen equilibrium lapse rates in their convective regions
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