1,280 research outputs found

    Fall versus Spring Nitrogen Fertilization on Pasture

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    Iowa livestock producers managing drought-stressed pastures wanted to know if grass-based pastures would recover more quickly or produce more forage by applying nitrogen to pastures in the fall versus their traditional spring application management. A pasture fertilization study was conducted on cool-season grassbased pastures at the Iowa State University Armstrong, Neely-Kinyon, and McNay Research and Demonstration Farms. Urea was hand applied at rates of 0, 22.5, 45, 66.7, and 90 lbs/acre to small plots at each site in October 2000. Some plots received 22.5 and 45 lbs/acre of N at the fall application date as the first half of a split application to total 45 and 90 lb/acre of N. The same N rates were applied to different plots and the remainder of the split application treatments was applied in March 2001. Dry matter yield was determined in mid-May 2001. Yields at the Neely-Kinyon and McNay farms were similar, and slightly higher than those at the Armstrong farm. Yield response to nitrogen application rates was positive and linear for each additional unit of nitrogen applied. The average total increase was about 38% for the first 45 lbsN/acre and about 81% for the 90 lbN/acre rates. There was no statistically significant or consistent relation between pasture yield increase and timing of nitrogen application across the three sites, but there were minor differences among sites. The trend, however, indicated that greater yields frequently were obtained from the early spring application treatments. Data was not collected to assess forage nutritive quality or stand density, however, both could be of value and importance to the long-term sustainability of a foragelivestock enterprise. These results indicate that for the period studied, there was no consistent advantage in applying nitrogen fertilizer to grass-based pastures in late fall or splitting the total application between fall and spring as compared to making traditional spring nitrogen applications

    Video: Adding to Your Case: Examining and Cross Examining Expert Witnesses

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    Learn skills for using expert witness testimony at trial: Developing strategy for selecting topics and order of presentation Using proper form of questioning on direct and cross Understanding rules of evidence, procedure, and ethics Two role play demonstrations help you learn technique

    Controlled nucleation of hydroxyapatite on alginate scaffolds for stem cell-based bone tissue engineering

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    Current bone tissue engineering strategies aim to grow a tissue similar to native bone by combining cells and biologically active molecules with a scaffold material. In this study, a macroporous scaffold made from the seaweed-derived polymer alginate was synthesized and mineralized for cell-based bone tissue engineering applications. Nucleation of a bone-like hydroxyapatite mineral was achieved by incubating the scaffold in modified simulated body fluids (mSBF) for 4 weeks. Analysis using scanning electron microscopy and energy dispersive x-ray analysis indicated growth of a continuous layer of mineral primarily composed of calcium and phosphorous. X-ray diffraction analysis showed peaks associated with hydroxyapatite, the major inorganic constituent of human bone tissue. In addition to the mineral characterization, the ability to control nucleation on the surface, into the bulk of the material, or on the inner pore surfaces of scaffolds was demonstrated. Finally, human MSCs attached and proliferated on the mineralized scaffolds and cell attachment improved when seeding cells on mineral coated alginate scaffolds. This novel alginate- HAP composite material could be used in bone tissue engineering as a scaffold material to deliver cells, and perhaps also biologically active molecules. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77954/1/32833_ftp.pd

    Dose-finding study of a 90-day contraceptive vaginal ring releasing estradiol and segesterone acetate.

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    ObjectiveTo evaluate serum estradiol (E2) concentrations during use of 90-day contraceptive vaginal rings releasing E2 75, 100, or 200 mcg/day and segesterone acetate (SA) 200 mcg/day to identify a dose that avoids hypoestrogenism.Study designWe conducted a multicenter dose-finding study in healthy, reproductive-aged women with regular cycles with sequential enrollment to increasing E2 dose groups. We evaluated serum E2 concentrations twice weekly for the primary outcome of median E2 concentrations throughout initial 30-day use (target ≄40 pg/mL). In an optional 2-cycle extension substudy, we randomized participants to 2- or 4-day ring-free intervals per 30-day cycle to evaluate bleeding and spotting based on daily diary information.ResultsSixty-five participants enrolled in E2 75 (n = 22), 100 (n = 21), and 200 (n = 22) mcg/day groups; 35 participated in the substudy. Median serum E2 concentrations in 75 and 100 mcg/day groups were <40 pg/mL. In the 200 mcg/day group, median E2 concentrations peaked on days 4-5 of CVR use at 194 pg/mL (range 114-312 pg/mL) and remained >40 pg/mL throughout 30 days; E2 concentrations were 37 pg/mL (range 28-62 pg/mL) on days 88-90 (n = 11). Among the E2 200 mcg/day substudy participants, all had withdrawal bleeding following ring removal. The 2-day ring-free interval group reported zero median unscheduled bleeding and two (range 0-16) and three (range 0-19) unscheduled spotting days in extension cycles 1 and 2, respectively. The 4-day ring-free interval group reported zero median unscheduled bleeding or spotting days.ConclusionsEstradiol concentrations with rings releasing E2 200 mcg/day and SA 200 mcg/day avoid hypoestrogenism over 30-day use.ImplicationsA 90-day contraceptive vaginal ring releasing estradiol 200 mcg/day and segesterone acetate 200 mcg/day achieves estradiol concentrations that should avoid hypoestrogenism and effectively suppresses ovulation

    Integrating the Use of Spring- and Fall-Calving Beef Cows in a Year-round Grazing System (A Progress Report)

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    Animal production, hay production and feeding, and the yields and composition of forage from summer and winter grass-legume pastures and winter corn crop residue fields from a year-round grazing system were compared with those of a conventional system. The year-round grazing system utilized 1.67 acres of smooth bromegrass-orchardgrass-birdsfoot trefoil pasture per cow in the summer, and 1.25 acres of stockpiled tall fescue-red clover pasture per cow, 1.25 acres of stockpiled smooth bromegrass-red clover pasture per cow, and 1.25 acres of corn crop residues per cow during winter for spring- and fall-calving cows and stockers. First-cutting hay was harvested from the tall fescue-red clover and smooth bromegrass-red clover pastures to meet supplemental needs of cows and calves during winter. In the conventional system (called the minimal land system), spring-calving cows grazed smooth bromegrass-orchardgrass-birdsfoot trefoil pastures at 3.33 acres/cow during summer with first cutting hay removed from one-half of these acres. This hay was fed to these cows in a drylot during winter. All summer grazing was done by rotational stocking for both systems, and winter grazing of the corn crop residues and stockpiled forages for pregnant spring-calving cows and lactating fall-calving cows in the year-round system was managed by strip-stocking. Hay was fed to springcalving cows in both systems to maintain a mean body condition score of 5 on a 9-point scale, but was fed to fall-calving cows to maintain a mean body condition score of greater than 3. Over winter, fall-calving cows lost more body weight and condition than spring calving cows, but there were no differences in body weight or condition score change between spring-calving cows in either system. Fall- and spring-calving cows in the yearround grazing system required 934 and 1,395 lb. hay dry matter/cow for maintenance during the winter whereas spring-calving cows in drylot required 4,776 lb. hay dry matter/cow. Rebreeding rates were not affected by management system. Average daily gains of spring-born calves did not differ between systems, but were greater than fall calves. Because of differences in land areas for the two systems, weight production of calves per acre of cows in the minimal land system was greater than those of the year-round grazing system, but when the additional weight gains of the stocker cattle were considered, production of total growing animals did not differ between the two systems

    Associations of gender and a proxy of female menopausal status with histological features of drug‐induced liver injury

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    Background & AimGender and menopause may contribute to type and severity of drug‐induced liver injury (DILI) by influencing host responses to injury. The aim of this study was to assess the associations of gender and female age 50 [a proxy of menopause] with histological features of liver injury in 212 adults enrolled in the Drug‐Induced Liver Injury Network (DILIN) registry.MethodsAll participants had a causality score of at least ‘probable’, a liver biopsy within 30 days of DILI onset, and no prior chronic liver disease. Biochemical and histological injury types were classified as hepatocellular or cholestatic/mixed injury. The cohort was divided into three gender/age categories: men (41.0%), women <50 years (27.4%) and women ≄50 years of age (31.6%). Interaction of gender and age category (≄50 or not) was assessed.ResultsHepatocellular injury was more prevalent in women <50 years vs. others (P=.002). After adjusting for biochemical injury types, black race and possible ageing effects, more severe interface hepatitis was noted in biopsies of women <50 years compared to those of men and women ≄50 years (P=.009 and P=.055 respectively). Compared to those of men, biopsies of women showed greater plasma cell infiltration, hepatocyte apoptosis, hepatocyte rosettes and lobular disarray but less iron‐positive hepatocytes and histological cholestasis (P<.05). These associations persisted after excluding cases of amoxicillin/clavulanic acid, anabolic steroids or nitrofurantoin DILI which showed gender‐specific distributions.ConclusionGender and a proxy of menopause were associated with various features of inflammation and injury in DILI.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139070/1/liv13380.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139070/2/liv13380_am.pd

    Climate change and stream temperature projections in the Columbia River basin: habitat implications of spatial variation in hydrologic drivers

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    Water temperature is a primary physical factor regulating the persistence and distribution of aquatic taxa. Considering projected increases in air temperature and changes in precipitation in the coming century, accurate assessment of suitable thermal habitats in freshwater systems is critical for predicting aquatic species\u27 responses to changes in climate and for guiding adaptation strategies. We use a hydrologic model coupled with a stream temperature model and downscaled general circulation model outputs to explore the spatially and temporally varying changes in stream temperature for the late 21st century at the subbasin and ecological province scale for the Columbia River basin (CRB). On average, stream temperatures are projected to increase 3.5 °C for the spring, 5.2 °C for the summer, 2.7 °C for the fall, and 1.6 °C for the winter. While results indicate changes in stream temperature are correlated with changes in air temperature, our results also capture the important, and often ignored, influence of hydrological processes on changes in stream temperature. Decreases in future snowcover will result in increased thermal sensitivity within regions that were previously buffered by the cooling effect of flow originating as snowmelt. Other hydrological components, such as precipitation, surface runoff, lateral soil water flow, and groundwater inflow, are negatively correlated to increases in stream temperature depending on the ecological province and season. At the ecological province scale, the largest increase in annual stream temperature was within the Mountain Snake ecological province, which is characterized by migratory coldwater fish species. Stream temperature changes varied seasonally with the largest projected stream temperature increases occurring during the spring and summer for all ecological provinces. Our results indicate that stream temperatures are driven by local processes and ultimately require a physically explicit modeling approach to accurately characterize the habitat regulating the distribution and diversity of aquatic taxa

    Integration of Year-round Forage Management Systems for Spring-calving and Fall-calving Beef Cows (A Progress Report)

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    Animal production, hay production and feeding, winter forage composition changes, and summer pasture yields and nutrient composition of a year-round grazing system for spring-calving and fall-calving cows were compared to those of a conventional, minimal land system. Cows in the year-round and minimal land systems grazed forage from smooth bromegrassorchardgrass-birdsfoot trefoil (SB-O-T) pastures at 1.67 and 3.33 acres, respectively, per cow in the summer. During the summer, SB-O-T pastures in the year-round grazing system also were grazed by stockers at 1.67 stockers per acre, and spring-calving and fall-calving cows grazed smooth bromegrass–red clover (SB-RC) and endophyte-free tall fescue–red clover (TF-RC) at 2.5 acres per cow for approximately 45 days in midsummer. In the year-round grazing system, spring-calving cows grazed corn crop residues at 2.5 acres per cow and stockpiled SB-RC pastures at 2.5 acres per cow; fallcalving cows grazed stockpiled TF-RC pastures at 2.5 acres per cow during winter. In the minimal land system, in winter, cows were maintained in a drylot on first-cutting hay harvested from 62.5–75% of the pasture acres during summer. Hay was fed to maintain a body condition score of 5 on a 9-point scale for springcalving cows in both systems and a body condition score of 3 for fall-calving cows in the year-round system. Over 3 years, mean body weights of fall-calving cows in the year-round system did not differ from the body weights of spring-calving cows in either system, but fall-calving cows had higher (P \u3c .05) body condition scores compared to spring-calving cows in either system. There were no differences among all groups of cows in body condition score changes over the winter grazing season (P \u3e .05). During the summer grazing season, fall-calving cows in the year- round system and springcalving cows in the minimal land system gained more body condition and more weight (P \u3c .05) than springcalving cows in the year-round grazing system. Fall calves in the year-round system had higher birth weights, lower weaning weights, and lower average preweaning daily gains compared to either group of spring calves (P \u3c .05). However, there were no significant differences for birth weights, weaning weights, or average pre-weaning daily gains between spring calves in either system over the 3-year experiment (P \u3e .05). The amount of total growing animal production (calves and stockers) per acre for each system did not differ in any year (P \u3e .05). Over the 3-year experiment, 1.9 ton more hay was fed per cow and 1 ton more hay was fed per cow–calf pair in the minimal land system compared to the year-round grazing system (P \u3c .05)

    Geodetic Constraints on the 2014 M 6.0 South Napa Earthquake

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    On 24 August 2014, the M 6.0 South Napa earthquake shook much of the San Francisco Bay area, leading to significant damage in the Napa Valley. The earthquake occurred in the vicinity of the West Napa fault (122.313° W, 38.22° N, 11.3 km), a mapped structure located between the Rodger’s Creek and Green Valley faults, with nearly pure right‐lateral strike‐slip motion (strike 157°, dip 77°, rake –169°; http://comcat.cr.usgs.gov/earthquakes/eventpage/nc72282711#summary, last accessed December 2014) (Fig. 1). The West Napa fault previously experienced an M 5 strike‐slip event in 2000 but otherwise exhibited no previous definitive evidence of historic earthquake rupture (Rodgers et al., 2008; Wesling and Hanson, 2008). Evans et al. (2012) found slip rates of ∌9.5  mm/yr along the West Napa fault, with most slip rate models for the Bay area placing higher slip rates and greater earthquake potential on the Rodger’s Creek and Green Valley faults, respectively (e.g., Savage et al., 1999; d’Alessio et al., 2005; Funning et al., 2007)
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