2,222 research outputs found

    Spatial and temporal variability in the relative contribution of king mackerel (Scomberomorus cavalla) stocks to winter mixed fisheries off South Florida

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    King mackerel (Scomberomorus cavalla) are ecologically and economically important scombrids that inhabit U.S. waters of the Gulf of Mexico (GOM) and Atlantic Ocean (Atlantic). Separate migratory groups, or stocks, migrate from eastern GOM and southeastern U.S. Atlantic to south Florida waters where the stocks mix during winter. Currently, all winter landings from a management-defined south Florida mixing zone are attributed to the GOM stock. In this study, the stock composition of winter landings across three south Florida sampling zones was estimated by using stock-specific otolith morphological variables and Fourier harmonics. The mean accuracies of the jackknifed classifications from stepwise linear discriminant function analysis of otolith shape variables ranged from 66−76% for sex-specific models. Estimates of the contribution of the Atlantic stock to winter landings, derived from maximum likelihood stock mixing models, indicated the contribution was highest off southeastern Florida (as high as 82.8% for females in winter 2001−02) and lowest off southwestern Florida (as low as 14.5% for females in winter 2002−03). Overall, results provided evidence that the Atlantic stock contributes a certain, and perhaps a significant (i.e., ≥50%), percentage of landings taken in the management-defined winter mixing zone off south Florida, and the practice of assigning all winter mixing zone landings to the GOM stock shoul

    Scale of Patchiness Affects the Relation Between Forage Quality and Patch Choice by Cattle

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    We predicted and tested the effects of scale of heterogeneity on movements and selectivity of a large grazer in a controlled field experiment. We created random mosaics of short/high quality and tall/low quality grass patches in equal proportion at grid sizes of 2x2 m and 5x5 m. Subsequently, we monitored the foraging behavior of four steers in 16 20x40 m plots over 30-minute periods. As predicted, the animals selected the short patches both by walking in a nonrandom manner and by concentrating their grazing time. Selectivity was more pronounced in large patches than in small ones. In contrast, the number of bites per feeding station was not affected by patch size, suggesting that selection between and within feeding stations are essentially different processes. We conclude that selectivity is facilitated by large scale heterogeneity, particularly by enhancing discrimination between feeding stations and larger selection units

    Remote sensing applications to resource problems in South Dakota

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    Cooperative projects between RSI and numerous South Dakota agencies have provided a means of incorporating remote sensing techniques into operational programs. Eight projects discussed in detail are: (1) detection of high moisture zones near interstate 90; (2) thermal infrared census of Canada geese in South Dakota; (3) dutch elm disease detection in urban environment; (4) a feasibility study for monitoring effective precipitation in South Dakota using TIROS-N; (5) open and abandoned dump sites in Spink county; (6) the influence of soil reflectance on LANDSAT signatures of crops; (7) A model implementation program for Lake Herman watershed; and (8) the Six-Mile Creek investigation follow-on

    Remote sensing applications to resource problems in South Dakota

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    The author has identified the following significant results. Change in the vegetative structure was taking place in the Black Hills. Temporal analysis of the areal extent of open meadows was accomplished using black and white and color infrared aerial photography. A reduction of nearly 1100 hectares of open meadows was determined using photointerpretation. Techniques were developed for the management of meandering lakes, including use of LANDSAT imagery for continuous monitoring, classification of hydrophytes on low altitude CIR imagery, and planning and evaluation of improvements and multiple uses on aerial photography and photo mosaics. LANDSAT data were analyzed statistically from small and entire study scene areas to determine the effect of soils stratifications of corn signatures. Band 5 early season and band 7 later season recorded the strongest evidence of the influence of soils on corn signatures. Significant strata were determined by a multiple range test

    An allelic polymorphism within the human tumor necrosis factor alpha promoter region is strongly associated with HLA A1, B8, and DR3 alleles.

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    The tumor necrosis factor (TNF) alpha gene lies within the class III region of the major histocompatibility complex (MHC), telomeric to the class II and centromeric to the class I region. We have recently described the first polymorphism within the human TNF-alpha locus. This is biallelic and lies within the promoter region. Frequency analysis of the TNF-alpha polymorphism, using the polymerase chain reaction and single-stranded conformational polymorphism, in HLA-typed individuals, reveals a very strong association between the uncommon TNF allele and HLA A1, B8, and DR3 alleles. This is the first association between TNF-alpha and other MHC alleles and raises the possibility that the uncommon TNF-alpha allele may contribute to the many autoimmune associations of the A1,B8,DR3 haplotype

    The Early Stages of Pedaliodes poesia (Hewitson, 1862) in Eastern Ecuador (Lepidoptera: Satyrinae: Pronophilina)

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    We describe the immature stages Pedaliodes poesia Hewitson, 1862 from northeastern Ecuador. Chusquea scandens (Poaceae, Bambusoidea) is the larval food plant. Eggs are laid singly or in pairs on the bottom side of host plant leaves. The duration of the egg, larval, and pupal stages, combined, is 99–107 days

    Factors Influencing Pediatric Dental Program Directorsâ Selection of Residents and Demographics of Current Directors

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    The primary goal of this study was to examine the criteria that influence rankings of candidates by advanced education program directors in pediatric dentistry. Secondary objectives were to obtain information on the resident selection process and to explore demographics of current program directors. A survey was sent in 2005 to all sixtyâ three program directors of pediatric dentistry residency programs accredited within the United States for the graduating class of 2007. The survey had a response rate of almost 78 percent (49/63). Respondents were requested to rank the importance of eleven factors that are typically included in the selection criteria for pediatric dentistry residents. Factors were rated on a scale of critical, very important, fairly important, somewhat important, and not important. The four highest ranked criteria by program directors were the following, in order: National Board scores, dental school clinical grades, class rank, and grade point average (GPA). Other factors ranked in descending order of perceived importance were the following: dental school basic science grades, experience in pediatric dentistry, extracurricular activities, completion of a general practice residency or advanced education in general dentistry program, the application essay, a publication or professional presentation, and private practice experience. All directors ranked personal interviews as very important to critical. Letters of recommendation from a pediatric dentistry department chairperson or faculty member were viewed more favorably than letters from dental school deans and nonâ pediatric dentistry faculty. Fiftyâ seven percent of the directors responding (28/49) were male, and 81 percent (40/49) were white, nonâ Hispanic. Fiftyâ nine percent of the directors (29/49) graduated from a residency program over twenty years ago, with 39 percent (19/49) having been a director for less than five years.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153594/1/jddj002203372009733tb04706x.pd

    Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies

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    The ocean is a major carbon sink and takes up 25%–30% of the anthropogenically emitted CO2. A state-of-the-art method to quantify this sink are global ocean biogeochemistry models (GOBMs), but their simulated CO2 uptake differs between models and is systematically lower than estimates based on statistical methods using surface ocean pCO2 and interior ocean measurements. Here, we provide an in-depth evaluation of ocean carbon sink estimates from 1980 to 2018 from a GOBM ensemble. As sources of inter-model differences and ensemble-mean biases our study identifies (a) the model setup, such as the length of the spin-up, the starting date of the simulation, and carbon fluxes from rivers and into sediments, (b) the simulated ocean circulation, such as Atlantic Meridional Overturning Circulation and Southern Ocean mode and intermediate water formation, and (c) the simulated oceanic buffer capacity. Our analysis suggests that a late starting date and biases in the ocean circulation cause a too low anthropogenic CO2 uptake across the GOBM ensemble. Surface ocean biogeochemistry biases might also cause simulated anthropogenic fluxes to be too low, but the current setup prevents a robust assessment. For simulations of the ocean carbon sink, we recommend in the short-term to (a) start simulations at a common date before the industrialization and the associated atmospheric CO2 increase, (b) conduct a sufficiently long spin-up such that the GOBMs reach steady-state, and (c) provide key metrics for circulation, biogeochemistry, and the land-ocean interface. In the long-term, we recommend improving the representation of these metrics in the GOBMs
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