The design of a research water table

A complete design for a research water table is presented. Following a brief discussion of the analogy between water and compressible-gas flows (hydraulic analogy), the components of the water table and their function are described. The major design considerations are discussed, and the final design is presented

Delayed Insemination of Non-Estrual Beef Heifers in 7-day CO-Synch Timed Artificial Insemination

Reproductive performance in cattle is considered to be the most economically important trait and is essential for the success of an operation. In the last decade, timed artificial insemination (AI) in the beef cattle industry has increased in popularity due to the decreased amount of labor required for estrous detection. To increase the use of AI; however, cost and time inputs need to be further decreased. The objective of this study was to determine if fertility could be improved in beef heifers that are not expressing estrus before timed AI by delaying insemination

Home ranges, movements and spatial relationships in an expanding population of black rhinoceros

Over 3000 sightings and fixes of individually identified black rhinoceros (Diceros bicornis minor ) over a 14-year period provided information on the spatial organization and movements of these introduced animals and their offspring in the Great Fish River Reserve, South Africa. Core home ranges based on 50% adaptive kernel calculations proved useful for depicting spatial associations among individuals and shifts in areas of occupation. The mean home range size (minimum convex polygon) was 11.7 km 2 and that of core adaptive kernel 6.8 km 2 . Annual and individual variations in home range size were great and social factors clearly affected size. For these and other reasons great caution is recommended in interpretation and inter-population comparisons of home range sizes. Most individuals in this expanding population showed mobility, with home ranges shifting over time. Although clearly exhibiting individual home ranges, most females associated in clusters of three or more individuals. Calves generally moved away from their mothers at the time of her next calving, but some subsequently moved back into their mothers' core home range. In addition to mother-offspring pairs, some females also showed multiple-year associations in these clusters. Male home ranges overlapped, and individuals showed multiple-year associations until they reached approximately nine years of age. Males over age 8 were rarely sighted in the core home range of other similarly aged males

Sedimentary Iron Cycling and the Origin and Preservation of Magnetization in Platform Carbonate Muds, Andros Island, Bahamas

Carbonate muds deposited on continental shelves are abundant and well-preserved throughout the geologic record because shelf strata are difficult to subduct and peritidal carbonate units often form thick, rheologically strong units that resist penetrative deformation. Much of what we know about pre-Mesozoic ocean chemistry, carbon cycling, and global change is derived from isotope and trace element geochemistry of platform carbonates. Paleomagnetic data from the same sediments would be invaluable, placing records of paleolatitude, paleogeography, and perturbations to the geomagnetic field in the context and relative chronology of chemostratigraphy. To investigate the depositional and early diagenetic processes that contribute to magneitzation in carbonates, we surveyed over 500 core and surface samples of peritidal, often microbially bound carbonate muds spanning the last not, vert, similar 1000 yr and deposited on top of Pleistocene aeolianites in the Triple Goose Creek region of northwest Andros Island, Bahamas. Sedimentological, geochemical, magnetic and ferromagnetic resonance properties divide the sediment columns into three biogeochemical zones. In the upper sediments, the dominant magnetic mineral is magnetite, produced by magnetotactic bacteria and dissimiliatory microbial iron metabolism. At lower depths, above or near mean tide level, microbial iron reduction dissolves most of the magnetic particles in the sediment. In some cores, magnetic iron sulfides precipitate in a bottom zone of sulfate reduction, likely coupled to the oxidation of decaying mangrove roots. The remanent magnetization preserved in all oriented samples appears indistinguishable from the modern local geomagnetic field, which reflects the post-depositional origin of magnetic particles in the lower zone of the parasequence. While we cannot comment on the effects of late-stage diagenesis or metamorphism on remanence in carbonates, we postulate that early-cemented, thin-laminated parasequence tops in ancient peritidal carbonates are mostly likely to preserve syn-depositional paleomagnetic directions and magnetofossil stratigraphies

Different histories but similar genetic diversity and structure for black walnut in Indiana and Missouri

—Missouri and Indiana have markedly different histories of glaciation and recolonization by forest trees. These states also differ in land use patterns and degree of anthropogenic landscape change such as forest fragmentation. To determine the overall effects of these and other demographic differences on the levels of genetic diversity and structure in black walnut (Juglans nigra L.) more than 550 total black walnut trees from nine populations in Indiana and 10 in Missouri were sampled and analyzed using 12 nuclear microsatellite loci. Although genetic diversity parameters such as allelic richness and expected heterozygosity were high overall, they varied little among populations and their mean values for the two states were not significantly different. Pairwise genetic distance values between all population pairs ranged from 0.012-0.159, but no significant pattern of isolation by distance was detected. The estimate of the degree of genetic differentiation between states (FPT = 0.0009) was very small and not significant, indicating that differences between states explained an inconsequential portion of the total variance. The observed low levels of local and regional genetic structure indicate that high levels of pollen flow have buffered black walnut from the genetic consequences of founder effects and genetic drift in both geologic and recent time scales

Yield and Nutritive Value of Heading and Headless Sorghum x Sudangrass Hybrids in Response to Cutting Frequency

Summer annual forages contribute greatly toward solving the problem of roughage supply for cattle in Korea. These forages support high levels of dairy and beef production during hot summer months when the quality and production of perennial herbage decreases due to unfavourable climatic conditions (Olson, 1971). This study investigated the effects of cutting frequency on dry matter (DM) yield and nutritive value of heading versus headless varieties of sorghum x sudangrass hybrid

Carbon Isotope and Lipid Biomarker Stratigraphy from Organic-Rich Strata Through the Neoproterozoic Shuram Excursion in South Oman

The regulation of oxygen levels in Earth’s atmosphere and oceans is inextricably linked to the carbon cycle. Carbon isotope ratios of carbonate and sedimentary organic matter provide first order insights into the operation of the carbon cycle in the geologic past. During the Ediacaran period, the ~580 Ma ‘Shuram Excursion’ (SE) records a dramatic, systematic shift in δ^(13)C_(carbonate) values to as low as cɑ. -12‰, lasting potentially millions to tens of millions of years in duration and constitutes the largest carbon isotope excursion known in the record [1]. The extremely negative carbon isotope values in carbonate challenges our understanding of the ancient carbon cycle and is difficult to rationalise via uniform carbon cycle principles. Several hypotheses have been developed to explain this behaviour, all of which make different predictions for the abundance, structure, and isotopic composition of organic carbon through the excursion. For a direct test of these ideas, we report paired organic and inorganic stable carbon isotope ratios in addition to detailed lipid biomarker stratigraphic records from a subsurface well drilled on the eastern flank of the South Oman Salt Basin, Sultanate of Oman. This well captures thermally immature and organic-rich Nafun Group strata traversing the SE, yielding variable but primary biomarker characteristics typical of Neoproterozoic rocks from this region. Despite the high organic matter contents, the carbon isotopic compositions of carbonates do not covary with those of organic phases. Furthermore, lipid biomarker data reveal that organic matter composition and source inputs varied stratigraphically, reflecting biological community shifts in non-migrated, syngenetic organic matter deposited during this interval. Together these observations imply that carbonateorganic isotopic decoupling during the SE is not a result of mixing of fossil or exogenous carbon sources (either DOC, detrital, or migrated) with syngenetic organic matter

Results of a production analysis survey of cow herds in Kansas

A survey of production levels and management practices of 205 cow herds representing over 26,000 cows in Kansas was conducted in 1991. These operations were located throughout Kansas except for the Northwest corner. Emphasis was placed on determining levels of production and reproductive parameters. Breeders emphasized calf crop. For example, the average calf crop was 91.6%, with 4.3% open females and 4.4% calf death loss. Cumulative calving percentages by 21-day calving periods were 32, 55, and 68%. Average weaning weights were 550 lb. for steers and 515 lb for heifers. Additionally, information was collected on breeding, nutrition, health, and general management practices

Population genetics reveals bidirectional fish movement across the Continental Divide via an interbasin water transfer

Interbasin water transfers are becoming an increasingly common tool to satisfy municipal and agricultural water demand, but their impacts on movement and gene flow of aquatic organisms are poorly understood. The Grand Ditch is an interbasin water transfer that diverts water from tributaries of the upper Colorado River on the west side of the Continental Divide to the upper Cache la Poudre River on the east side of the Continental Divide. We used single nucleotide polymorphisms to characterize population genetic structure in cutthroat trout (Oncorhynchus clarkii) and determine if fish utilize the Grand Ditch as a movement corridor. Samples were collected from two sites on the west side and three sites on the east side of the Continental Divide. We identified two or three genetic clusters, and relative migration rates and spatial distributions of admixed individuals indicated that the Grand Ditch facilitated bidirectional fish movement across the Continental Divide, a major biogeographic barrier. Previous studies have demonstrated ecological impacts of interbasin water transfers, but our study is one of the first to use genetics to understand how interbasin water transfers affect connectivity between previously isolated watersheds. We also discuss implications on native trout management and balancing water demand and biodiversity conservation

Switchgrass Response to Nitrogen Fertilizer Across Diverse Environments in the USA: a Regional Feedstock Partnership Report

The Regional Feedstock Partnership is a collaborative effort between the Sun Grant Initiative (through Land Grant Universities), the US Department of Energy, and the US Department of Agriculture. One segment of this partnership is the field-scale evaluation of switchgrass (Panicum virgatum L.) in diverse sites across the USA. Switchgrass was planted (11.2 kg PLS ha−1 ) in replicated plots in New York, Oklahoma, South Dakota, and Virginia in 2008 and in Iowa in 2009. Adapted switchgrass cultivars were selected for each location and baseline soil samples collected before planting. Nitrogen fertilizer (0, 56, and 112 kg N ha−1 ) was applied each spring beginning the year after planting, and switchgrass was harvested once annually after senescence. Establishment, management, and harvest operations were completed using fieldscale equipment. Switchgrass production ranged from 2 to 11.5 Mg ha−1 across locations and years. Yields were lowest the first year after establishment. Switchgrass responded positively to N in 6 of 19 location/year combinations and there was one location/year combination (NY in Year 2) where a significant negative response was noted. Initial soil N levels were lowest in SD and VA (significant N response) and highest at the other three locations (no N response). Although N rate affected some measures of biomass quality (N and hemicellulose), location and year had greater overall effects on all quality parameters evaluated. These results demonstrate the importance of local field-scale research and of proper N management in order to reduce unnecessary expense and potential environmental impacts of switchgrass grown for bioenergy