168 research outputs found
Evaluation of the stock structure of cobia (Rachycentron canadum) in the southeastern United States by using dart-tag and genetics data
Available tag-recapture and population genetics data for cobia (Rachycentron canadum) in the south-eastern United States were evaluated to provide information on population structure and determine the geographic boundary between stocks in the Gulf of Mexico and the Atlantic Ocean. The movements of 1750 cobia were evaluated on the basis of assigned tagging and recapture zones. Genetic samples from an additional 2796 cobia collected during the presumed spawning season were genotyped at 10 microsatellite loci, and standard population genetic statistical analyses were applied to the resulting sample data set. Tag- recapture results indicate that cobia tagged south of Cape Canaveral, Florida, primarily move between that area and the Gulf of Mexico and that cobia tagged north of Georgia have little interaction with the area south of Cape Canaveral. Cobia tagged at Cape Canaveral distributed widely throughout the entire southeastern coast of the United States. Genetic analysis results agree, indicating separate stocks that occur from Texas through Hobe Sound on the east coast of Florida and from Savannah, Georgia, to the Chesapeake Bay in Virgina, with distinct genetic groupings within the Atlantic Ocean stock. The results indicate a transition area that occurs from Cape Canaveral through northern Georgia, and additional data from this region are necessary to further refine the stock boundary
Mars oxygen production system design
The design and construction phase is summarized of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere was assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer compatible data acquisition and control instrumentation is ongoing
Recommended from our members
L-DART: Direct Analysis Of Resource Traps within Lunar Permanently Shadowed Regions by a Penetrator Mission
Recommended from our members
L-DART: A Penetrator Mission for Lunar Permanently Shadowed Regions
Lunar Direct Analysis of Resource Traps (L‐DART) will address many current knowledge gaps concerning lunar volatiles and permanently shadowed regions (PSRs), providing in-situ ground truth data to calibrate numerous existing remote datasets. It builds on UK expertise in developing and testing penetrator system concepts for the Moon and Europa (e.g. MOONLITE). Following release of a Penetrator Descent Module in lunar orbit (Figure 1), its Penetrator Delivery System performs de-orbit and orientation before releasing the instrumented Penetrator to penetrate a few meters into target lunar surface at ~300 m/s. The penetrator itself serves as the sampling tool and an on-board mass spectrometer analyses in-situ the volatiles released both in the impact and in the subsequent thermal soak from lander to surrounding regolith. A pair of 3‐axis accelerometers measure regolith structure during the landing event and constrain penetrator final location. Temperature sensors enable regolith thermal properties to be deduced. Pre-and post impact imagery is obtained for context. Science is complete and data relayed to Earth within 1-2 hours, minimizing system mass and lifetime requirements. Possible landing sites include Cabeus (for comparison with LCROSS) or Shoemaker which exhibits excess hydrogen, or areas indicated by LRO to exhibit putative surface frost. Alternatively, L‐DART could target the hypothesised ancient (paleo) south pole and hence potentially ancient volatiles
Tikhonov adaptively regularized gamma variate fitting to assess plasma clearance of inert renal markers
The Tk-GV model fits Gamma Variates (GV) to data by Tikhonov regularization (Tk) with shrinkage constant, λ, chosen to minimize the relative error in plasma clearance, CL (ml/min). Using 169Yb-DTPA and 99mTc-DTPA (n = 46, 8–9 samples, 5–240 min) bolus-dilution curves, results were obtained for fit methods: (1) Ordinary Least Squares (OLS) one and two exponential term (E1 and E2), (2) OLS-GV and (3) Tk-GV. Four tests examined the fit results for: (1) physicality of ranges of model parameters, (2) effects on parameter values when different data subsets are fit, (3) characterization of residuals, and (4) extrapolative error and agreement with published correction factors. Test 1 showed physical Tk-GV results, where OLS-GV fits sometimes-produced nonphysical CL. Test 2 showed the Tk-GV model produced good results with 4 or more samples drawn between 10 and 240 min. Test 3 showed that E1 and E2 failed goodness-of-fit testing whereas GV fits for t > 20 min were acceptably good. Test 4 showed CLTk-GV clearance values agreed with published CL corrections with the general result that CLE1 > CLE2 > CLTk-GV and finally that CLTk-GV were considerably more robust, precise and accurate than CLE2, and should replace the use of CLE2 for these renal markers
Composting of rice straw with effective microorganisms (EM) and its influence on compost quality.
This study aims to assess the effect of EM application on the composting process of rice straw with goat manure and green waste and to evaluate the quality of both compost treatments. There are two treatment piles in this study, in which one pile was applied with EM and another pile without EM. Each treatment was replicated three times with 90 days of composting duration. The parameters for the temperature, pH, TOC and C/N ratio, show that decomposition of organic matter occurs during the 90-day period. The t-test conducted shows that there is a significant difference between compost with EM and compost without EM. The application of EM in compost increases the macro and micronutrient content. The following parameters support this conclusion: compost applied with EM has more N, P and K content (P < 0.05) compared to compost without EM. Although the Fe in compost with EM is much higher (P < 0.05) than in the compost without EM, for Zn and Cu, there is no significant difference between treatments. This study suggests that the application of EM is suitable to increase the mineralization in the composting process. The final resultant compost indicated that it was in the range of the matured level and can be used without any restriction
Hired Tobacco Harvest Work Force Characteristics in an Eight County Area of North Carolina
Development of a labor market study in a flue-cured tobacco production region in Eastern North Carolina in response to probable rapid mechanization of the harvest is described. Preliminary analysis of the characteristics. of individual workers and their potential for adjustment is presented. Needed and prospective analyses are also specified
- …