1,868 research outputs found

    Illiquid Capital: Are Conservation Easement Payments Reinvested in Farms?

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    Agricultural conservation easements have positive externalities but few studies examine the supply-side. This paper explores whether easements may also overcome a credit-market failure, as banks may not be lending based on the full developed value of land. Original survey data test our research hypotheses and show profitable owners and nonoperators to be using easement payments to extract capital from their land by using the preservation programs as a bank. The results also show that the unprofitable owners and operators are reinvesting in their agricultural enterprises. Both results are consistent with an underlying credit-market failure, and the latter suggests that easements may provide indirect efficiency enhancement. The results suggest an integration of policies on agricultural finance and land preservation might lead to improved efficiency

    Effect of heifer source on reproductive performance, culling, marketing and profitability for a commercial heifer development program

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    A commercial heifer development operation purchased 483 weanling Angus × Hereford heifers from 11 sources. Heifers were fed a common silage-based diet through an initial developmental period and retained or culled based on average daily gain, pelvic area, and disposition . The percentage of heifers culled from each source ranged from 18.1% to 94.7% and were either sold directly through a local sale barn or sent to a feedlot with retained ownership . Estrus was synchronized, and heifers were artificially inseminated (AI) for 30 days followed by 15 days of natural mating. First service conception rates for each source ranged from 0% to 92.3%, whereas overall pregnancy rates for the 45-day breeding season ranged from 81.3% to 100%. When expressed as a percentage of the original heifers purchased from each source, overall pregnancy rates ranged from 5.3% to 80%. Heifers that lost their fetuses were sold for a net loss of 213perhead.HeiferssoldasfirstserviceAIbred,secondserviceAIbred,andnaturallymatednetted213 per head. Heifers sold as first service AI bred, second service AI bred, and naturally mated netted 160, 129,and129, and 89 per head, respectively. With accurate records, stringent culling practices, and evaluation of cost and performance, producers can optimize profit potential of replacement heifers. Early culling and pregnancy diagnosis also will decrease costs while increasing opportunities to minimize the financial risks

    A three-year economic evaluation of a commercial heifer development program

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    In 1994, 1995, and 1996, a commercial heifer development operation purchased a total of 1542 potential replacement heifers. Heifers were purchased in the fall proceeding the spring breeding season and fed a silage-based diet during the developmental period. Before the breeding season began, heifers that failed to meet minimum requirements for pelvic area, average daily gain, body weight, disposition, or structural soundness were culled. During the first year, 42% of 483 heifers were culled, 17% of 468 heifers were culled in the second year, and 14% of 591 heifers in the third year. Estrus was synchronized and heifers were inseminated artificially (AI) for 30 days followed by 30 days of natural mating by cleanup bulls. First-service AI conception rates averaged 68% and overall pregnancy rates (AI + natural mating) averaged 95.1% over the 3-year period. Heifers culled prior to the breeding season realized a net profit of 9perhead,whereasheifersdiagnosednonpregnantafterthebreedingseasonlost9 per head, whereas heifers diagnosed nonpregnant after the breeding season lost 86, and heifers that aborted lost 133.Profitsforpregnantheiferssoldwere133. Profits for pregnant heifers sold were 163 for first-service AI, 138forsecondserviceAI,and138 for second-service AI, and 83 for bull bred

    An Arctic Disaster and its Policy Implications

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    The purpose of the research reported here is to help the community in Barrow, Alaska, clarify its vulnerability to extreme weather events, and devise better-informed policies for reducing that vulnerability and adapting to climate variability and change. We examine the worst disaster on record there - a storm that struck on 3 October 1963 - from different disciplinary perspectives and in the context of other severe storms. The major policy responses to date have been a beach nourishment program, a feasibility study of additional means of erosion control, and an emergency management plan. Additional possible responses have been identified in the community's cumulative experience of these storms, but have not yet been fully explored or implemented. Meanwhile, given inherent uncertainties, it is clear that sound policies will allow for corrective action if and when expectations based on the best available knowledge and information turn out to be mistaken. It is also clear that the people of Barrow are in the best position to understand the evolving situation and to decide what to do about it.Les travaux de recherche que l'on présente ici ont pour but d'aider la collectivité de Barrow (Alaska) à définir son degré de vulnérabilité à des conditions climatiques extrêmes, et à créer des politiques plus éclairées qui réduiraient cette vulnérabilité et favoriseraient l'adaptation à la variabilité et au changement climatiques. On examine le pire désastre jamais enregistré à cet endroit, soit une tempête qui fit rage le 3 octobre 1963, et ce, sous l'angle de différentes disciplines et dans le contexte d'autres grandes tempêtes. Jusqu'à présent, les politiques majeures d'intervention se sont résumées à un programme de recharge de plage, à une étude de faisabilité portant sur des mesures supplémentaires de lutte contre l'érosion et à un plan de gestion des situations d'urgence. L'expérience cumulative de la collectivité relative à ces tempêtes a permis de dégager d'autres interventions possibles, sans qu'elles aient toutefois été explorées à fond ou concrétisées. Entre-temps, vu les incertitudes inhérentes à ce genre de choses, il est évident que des politiques bien pensées permettront l'application de mesures correctives si et quand les prédictions fondées sur les toutes dernières connaissances et informations disponibles s'avèrent erronées. Il est en outre évident que les habitants de Barrow sont les mieux placés pour comprendre comment la situation évolue et pour décider des mesures à prendre

    Timing of gain does not alter puberty and reproductive performance of beef heifers fed a high-roughage diet

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    Eighty crossbred heifers (549 lb initial body weight) were developed in drylot and limit-fed a forage sorghum silage diet predicted to produce gains of either 1 lb/day for the entire developmental period (EVENGAIN) or .25 lb/day for the first two-thirds of the period followed by 2 lb/day during the last third (LATEGAIN). Treatments began on November 7, 1994 and continued until April 24, 1995 (onset of the breeding season). Actual daily gains over the entire feeding period averaged 1.18 and 1.10 lb/day for EVENGAIN and LATEGAIN heifers, respectively. Age and weight at puberty were not affected by feeding treatment. Body condition score, frame score, and pelvic area were similar at the end of the experiment regardless of growth regimen. At the conclusion of the 168-day feeding period, estrus was synchronized using two injections of prostaglandin F2 , and heifers were inseminated artificially during a 45-day breeding season. Open heifers were mated naturally for an additional 15 days. First service and overall pregnancy rates were similar between treatments. In summary, timing of gain did not affect the onset of puberty or breeding performance. These data indicate that bee f producers may be able to utilize low quality feedstuffs early in heifer development without adversely affecting reproductive performance. Because feed inputs are major costs for developing beef heifers, such a management alternative may decrease costs

    The cariogenic effect of starch on oral microcosm grown within the dual constant depth film fermenter

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    Evidence on the link between starch intake and caries incidence is conflicting, therefore the cariogenicity of starch compared with sucrose was explored using a dual Constant Depth Film Fermenter (dCDFF) biotic model system. Bovine enamel discs were used as a substrate and the dCDFF was inoculated using human saliva. CDFF units were supplemented with artificial saliva growth media at a constant rate to mimic resting salivary flow rate over 14 days. The CDFF units were exposed to different conditions, 2 % sucrose or 2 % starch 8 times daily and either no additional fluoride or 1450 ppm F- twice daily. Bovine enamel discs were removed at intervals (days 3, 7, 10 and 14) for bacterial enumeration and enamel analysis using Quantitative Light Induced Fluorescence (QLF) and Transverse Microradiography (TMR). Results showed that in the absence of fluoride there was generally no difference in mineral loss between enamel exposed to either sucrose or starch when analysed using TMR and QLF (P > 0.05). In the presence of fluoride by day 14 there was significantly more mineral loss under starch than sucrose when analysed with TMR (P < 0.05). It was confirmed that starch and sucrose are similarly cariogenic within the dCDFF in the absence of fluoride. With the aid of salivary amylase, the bacteria utilise starch to produce an acidic environment similar to that of bacteria exposed to sucrose only. In the presence of fluoride, starch was more cariogenic which may be due to the bacteria producing a more hydrophobic intercellular matrix lowering the penetration of fluoride through the biofilm. This is significant as it indicates that the focus on sugars being the primary cause of caries may need re-evaluating and an increase in focus on carbohydrates is needed as they may be similarly cariogenic as sugars if not more so

    Quantifying the Demineralisation of Enamel Using a Hyperspectral Camera Measuring Fluorescence Loss

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    Background The gold standard for quantifying mineral loss of enamel is transverse microradiography (TMR) and is complimented by the non-destructive quantitative light induced fluorescence (QLF) which measures changes in autofluorescence. Fluorescence loss has been shown to correlate with mineral loss. Building upon the established method, the use of hyperspectral fluorescence imaging (HI) allows the capture of a broader range of wavelengths to quantify fluorescence changes more accurately. Methods Bovine Enamel was demineralised within the dual constant depth film fermenter over 14 days and analysed using TMR, QLF and HI. The mineral change values were compared using Pearson's Correlation Coefficient. Results The analysis showed a statistically significant correlation that was equal between TMR and HI (r = 0.844) and TMR and QLF (r = 0.844), but weaker between QLF and HI (r = 0.811). Conclusions The correlations indicate that HI is a promising valid non-destructive method for quantifying mineral loss from bovine enamel that is as accurate as QLF and complements TMR

    Parity violating pion electroproduction off the nucleon

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    Parity violating (PV) contributions due to interference between γ\gamma and Z0Z^0 exchange are calculated for pion electroproduction off the nucleon. A phenomenological model with effective Lagrangians is used to determine the resulting asymmetry for the energy region between threshold and Δ(1232)\Delta(1232) resonance. The Δ\Delta resonance is treated as a Rarita-Schwinger field with phenomenological NΔN \Delta transition currents. The background contributions are given by the usual Born terms using the pseudovector πN\pi N Lagrangian. Numerical results for the asymmetry are presented.Comment: 17 pages, RevTeX, 6 figures (in separate file figs.uu), uses epsf, accepted for publication in Z. Phys.

    Endovascular Repair of Abdominal Aortic Aneurysm does not Improve Early Survival versus Open Repair in Patients Younger than 60 Years

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    AbstractObjectivesMultiple randomised trials have demonstrated lower perioperative mortality after endovascular aneurysm repair (EVAR) compared to open surgical repair for infrarenal abdominal aortic aneurysms (AAAs). However, in these trials the mortality advantage for EVAR is being lost within 2 years of repair and the patients evaluated are relatively older with no study specifically comparing EVAR and open repair for patients younger than 60 years of age.DesignA retrospective analysis of prospectively collected data.Materials and methodsPatients younger than 60 years of age who underwent EVAR and open surgical repair for elective infrarenal AAA were identified from the 2007–09 National Surgical Quality Improvement Program (NSQIP) – a prospective database maintained at 237 centres across the United States. Univariate and multivariate analyses were performed.ResultsOf the 651 patients, 369 (56.7%) underwent EVAR and 282 (43.3%) underwent open repair. Thirty-day mortality for EVAR and open repair were 1.1% and 0.4%, respectively. This was not significantly different on univariate (P = 0.22) as well as multivariate (P = 0.69) analysis after controlling for other co-morbidities. On multivariate analysis, body mass index, history of stroke and bleeding disorder prior to surgery were associated with a higher 30-day mortality after AAA repair (combined open and EVAR).ConclusionsThese contemporary results demonstrate that the 30-day mortality rate after open repair is similar to that after EVAR in patients younger than 60 years with infrarenal AAA
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