259 research outputs found

    CurvedLand: An Applet for Illustrating Curved Geometry without Embedding

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    We have written a Java applet to illustrate the meaning of curved geometry. The applet provides a mapping interface similar to MapQuest or Google Maps; features include the ability to navigate through a space and place permanent point objects and/or shapes at arbitrary positions. The underlying two-dimensional space has a constant, positive curvature, which causes the apparent paths and shapes of the objects in the map to appear distorted in ways that change as you view them from different relative angles and distances.Comment: 4 page

    Effects of Corn Processing Method and Crude Protein Level with the Inclusion of Wet Corn Gluten Feed on Finishing Steer Performance

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    Three hundred twenty crossbred steer calves were used to evaluate corn processing method and crude protein level in finishing diets that included wet corn gluten feed. There was no response due to crude protein level (14 vs 15%) observed in this trial. As corn processing method became more intensive (fine-grinding, high-moisture ensiling, and steam-flaking corn) compared to dry-rolling, daily intake was reduced. Daily gain was similar across corn processing methods. Feed efficiency and cost of gain improved as corn processing method intensity increased

    Using beet pulp to adapt cattle to finishing diets compared to traditional grain adaptation with alfalfa hay

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    A study was conducted to compare grain adaptation programs using beet pulp (BP) to traditional grain adaptation with alfalfa hay (AH). Yearling crossbred steers (n = 232; BW = 326 ± 14.5 kg) were separated into 3 weight blocks, stratified by BW, and assigned randomly, within strata, to 18 feedlot pens, with 12 or 13 steers per pen. Treatments were imposed during grain adaptation (21 d) using 3 grain adaptation programs. Within each grain adaptation program, 4 step rations were fed for 3, 4, 7, and 7 d. Each program increased dry-rolled corn inclusion while roughage inclusion decreased. In the control treatment (CON), AH inclusion decreased from 46 to 6% and pressed BP (24% DM) was held constant at 6% in all step rations. Beet pulp adaptation programs included a low BP treatment (LOBP) where BP was decreased from 18 to 6% and AH from 34 to 6% or a high BP treatment (HIBP) in which both BP and AH were decreased from 26 to 6%. On d 22 through the remainder of the finishing period cattle were fed a common diet (62% dry rolled corn, 20% wet distillers grains with solubles, 6% AH, 6% BP, 0.25% urea, and 5.75% liquid supplement DM basis). During grain adaptation, cattle fed CON tended (P = 0.07 for overall F test, P = 0.02 for mean comparison) to have greater DMI than HIPB and LOPB was intermediate (9.9, 9.5, and 9.7 kg, respectively). Gain and G:F were not different (P \u3e 0.19) among treatments during the grain adaptation period. However, based off of carcass adjusted final BW, steers adapted using HIBP and LOBP tended (P = 0.07 for overall F-test, P = 0.04 for mean comparison) to have greater ADG compared with CON (1.65, 1.72, and 1.73 kg, respectively). Overall G:F was not different (P = 0.11) among treatments. Dry matter intakes were not different across all treatments (P = 0.58). Carcass characteristics were not affected by adaptation method (P \u3e 0.31). Replacing up to 50% of AH with BP during grain adaptation increased ADG and may be used as an alternative to conventional adaptation programs

    Association of Myostatin on Performance and Carcass Traits in Crossbred Cattle

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    Calf-fed steers and yearling heifersgenotyped as homozygous active, heterozygous, or homozygous inactive for myostatin were used to evaluate performance and carcass traits from Piedmontese influenced cattle. Homozygous inactive steers had similar ADG, lower DMI and lower F:G when compared to steers influenced by active myostatin. Steers and heifers with inactive myostatin showed similar trends in carcass traits producing larger LM area, greater dressing percentages and leaner carcasses. Similar ADG, lower DMI, and improved F:G were observed for homozygous inactive compared to homozygous active steers. Cattle with inactive myostatin require more days on feed than homozygous active cattle to reach similar live BW and 12th rib fat endpoints

    Association of Myostatin on Performance and Carcass Traits in Crossbred Cattle

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    Calf-fed steers and yearling heifersgenotyped as homozygous active, heterozygous, or homozygous inactive for myostatin were used to evaluate performance and carcass traits from Piedmontese influenced cattle. Homozygous inactive steers had similar ADG, lower DMI and lower F:G when compared to steers influenced by active myostatin. Steers and heifers with inactive myostatin showed similar trends in carcass traits producing larger LM area, greater dressing percentages and leaner carcasses. Similar ADG, lower DMI, and improved F:G were observed for homozygous inactive compared to homozygous active steers. Cattle with inactive myostatin require more days on feed than homozygous active cattle to reach similar live BW and 12th rib fat endpoints

    The effect of acute exercise on objectively measured sleep and cognition in older adults

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    Background: Exercise can improve cognition in aging, however it is unclear how exercise influences cognition, and sleep may partially explain this association. The current study aimed to investigate whether objectively measured sleep mediates the effect of an acute exercise intervention on cognition in older adults. Methods: Participants were 30 cognitively unimpaired, physically active older adults (69.2 ± 4.3 years) with poor sleep (determined via self-report). After a triple baseline cognitive assessment to account for any natural fluctuation in cognitive performance, participants completed either a single bout of 20-minutes of high intensity exercise on a cycle ergometer, or a control condition, in a cross-over trial design. Cognition was measured immediately post-intervention and the following day, and sleep (total sleep time, sleep onset latency, sleep efficiency, % of rapid eye movement sleep, light sleep and deep sleep) was characterized using WatchPAT™ at baseline (5 nights) and measured for one night after both exercise and control conditions. Results: Results showed no effect of the exercise intervention on cognition immediately post-intervention, nor an effect of acute exercise on any sleep variable. There was no mediating effect of sleep on associations between exercise and cognition. However, a change from baseline to post-intervention in light sleep and deep sleep did predict change in episodic memory at the ~24 h post-intervention cognitive assessment, regardless of intervention condition. Discussion: There was no effect of acute high intensity exercise on sleep or cognition in the current study. However, results suggest that associations between sleep and cognition may exist independently of exercise in our sample. Further research is required, and such studies may aid in informing the most effective lifestyle interventions for cognitive health

    The effect of acute exercise on objectively measured sleep and cognition in older adults

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    BackgroundExercise can improve cognition in aging, however it is unclear how exercise influences cognition, and sleep may partially explain this association. The current study aimed to investigate whether objectively measured sleep mediates the effect of an acute exercise intervention on cognition in older adults.MethodsParticipants were 30 cognitively unimpaired, physically active older adults (69.2 ± 4.3 years) with poor sleep (determined via self-report). After a triple baseline cognitive assessment to account for any natural fluctuation in cognitive performance, participants completed either a single bout of 20-minutes of high intensity exercise on a cycle ergometer, or a control condition, in a cross-over trial design. Cognition was measured immediately post-intervention and the following day, and sleep (total sleep time, sleep onset latency, sleep efficiency, % of rapid eye movement sleep, light sleep and deep sleep) was characterized using WatchPAT™ at baseline (5 nights) and measured for one night after both exercise and control conditions.ResultsResults showed no effect of the exercise intervention on cognition immediately post-intervention, nor an effect of acute exercise on any sleep variable. There was no mediating effect of sleep on associations between exercise and cognition. However, a change from baseline to post-intervention in light sleep and deep sleep did predict change in episodic memory at the ~24 h post-intervention cognitive assessment, regardless of intervention condition.DiscussionThere was no effect of acute high intensity exercise on sleep or cognition in the current study. However, results suggest that associations between sleep and cognition may exist independently of exercise in our sample. Further research is required, and such studies may aid in informing the most effective lifestyle interventions for cognitive health

    An assessment of implementation of community - oriented primary care in Kenyan family medicine postgraduate medical education programmes

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    Background and objectives: Family medicine postgraduate programmes in Kenya are examining the benefits of Community-Oriented Primary Care (COPC) curriculum, as a method to train residents in population-based approaches to health care delivery. Whilst COPC is an established part of family medicine training in the United States, little is known about its application in Kenya. We sought to conduct a qualitative study to explore the development and implementation of COPC curriculum in the first two family medicine postgraduate programmes in Kenya. Method: Semi-structured interviews of COPC educators, practitioners, and academic stakeholders and focus groups of postgraduate students were conducted with COPC educators, practitioners and academic stakeholders in two family medicine postgraduate programmes in Kenya. Discussions were transcribed, inductively coded and thematically analysed. Results: Two focus groups with eight family medicine postgraduate students and interviews with five faculty members at two universities were conducted. Two broad themes emerged from the analysis: expected learning outcomes and important community-based enablers. Three learning outcomes were (1) making a community diagnosis, (2) understanding social determinants of health and (3) training in participatory research. Three community-based enablers for sustainability of COPC were (1) partnerships with community health workers, (2) community empowerment and engagement and (3) institutional financial support. Conclusions: Our findings illustrate the expected learning outcomes and important communitybased enablers associated with the successful implementation of COPC projects in Kenya and will help to inform future curriculum development in Kenya

    Linking Ecology and Economics for Ecosystem Management

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    This article outlines an approach, based on ecosystem services, for assessing the trade-offs inherent in managing humans embedded in ecological systems. Evaluating these trade-offs requires an understanding of the biophysical magnitudes of the changes in ecosystem services that result from human actions, and of the impact of these changes on human welfare.We summarize the state of the art of ecosystem services?based management and the information needs for applying it. Three case studies of Long Term Ecological Research (LTER) sites?coastal, urban, and agricultural? illustrate the usefulness, information needs, quantification possibilities, and methods for this approach. One example of the application of this approach, with rigorously established service changes and valuations taken from the literature, is used to illustrate the potential for full economic valuation of several agricultural landscape management options, including managing for water quality, biodiversity, and crop productivity
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