5,309 research outputs found

    Production Inefficiency in Fed Cattle Marketing and the Value of Sorting Pens into Alternative Marketing Groups Using Ultrasound Technology

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    The cattle industry batch markets animals in pens. Because of this, animals within any one pen can be both underfed and overfed. Thus, there is a production inefficiency associated with batch marketing. We simulate the value of sorting animals through weight and ultrasound measurements from original pens into smaller alternative marketing groups. Sorting exploits the production inefficiency and enables cattle feeding enterprises to avoid meat quality discounts, capture premiums, more efficiently use feed resources, and increase returns. The value of sorting is between 15and15 and 25 per head, with declining marginal returns as the number of sort groups increases.cattle feeding, production efficiency, simulation, sorting, value-based marketing, ultrasound, Agribusiness, Livestock Production/Industries, Marketing, Research and Development/Tech Change/Emerging Technologies, C15, D21, D23, Q12,

    RETURNS TO SORTING AND MARKET TIMING OF ANIMALS WITHIN PENS OF FED CATTLE

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    This research examines returns to cattle feeding operations that sort animals prior to marketing using ultrasound technology. The returns to sorting are between 11and11 and 25 per head depending on the number of groups the pens into which cattle can be sorted. Sorting faces declining returns. These returns can also be viewed as the costs imposed by institutional constraints that limit co-mingling of cattle. Through sorting, cattle feeding operations are able to reduce meat quality discounts, increase meat quality premiums, increase beef carcass quality characteristics, more efficiently use feed resources, and increase profits.Livestock Production/Industries,

    Hubble Servicing Challenges Drive Innovation of Shuttle Rendezvous Techniques

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    Hubble Space Telescope (HST) servicing, performed by Space Shuttle crews, has contributed to what is arguably one of the most successful astronomy missions ever flown. Both nominal and contingency proximity operations techniques were developed to enable successful servicing, while lowering the risk of damage to HST systems, and improve crew safety. Influencing the development of these techniques were the challenges presented by plume impingement and HST performance anomalies. The design of both the HST and the Space Shuttle was completed before the potential of HST contamination and structural damage by shuttle RCS jet plume impingement was fully understood. Relative navigation during proximity operations has been challenging, as HST was not equipped with relative navigation aids. Since HST reached orbit in 1990, proximity operations design for servicing missions has evolved as insight into plume contamination and dynamic pressure has improved and new relative navigation tools have become available. Servicing missions have provided NASA with opportunities to gain insight into servicing mission design and development of nominal and contingency procedures. The HST servicing experiences and lessons learned are applicable to other programs that perform on-orbit servicing and rendezvous, both human and robotic

    The Spontaneous Culture Method for Studying the Non-Symbiotic Nitrogen Fixing Bacteria of the Soil

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    During the years which have elapsed since the discovery of the non-symbiotic nitrogen-fixing bacteria there have been extensive investigations on the characteristics and activities of this group of organisms. They have been found to be of great importance from the fertility standpoint, adding appreciable amounts of nitrogen to the soil annually where the conditions are favorable for their development. In many cases too, a correlation has been found between the ability of a soil to support a vigorous Azotobacter growth and its crop producing power

    Multicenter prospective cohort study of the Strata valve for the management of hydrocephalus in pediatric patients

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    Journal ArticleObject. Previous reports suggest that adjustable valves may improve the survival of cerebrospinal fluid shunts or relieve shunt-related symptoms. To evaluate these claims, the authors conducted a prospective multicenter cohort study of children who underwent placement of Strata valves. Methods. Patients undergoing initial shunt placement (Group 1) or shunt revision (Group 2) were treated using Strata valve shunt systems. Valves were adjustable to five performance level settings by using an externally applied magnet. The performance levels were checked using an externally applied hand tool and radiography. Patients were followed for 1 year or until they underwent shunt revision surgery. Between March 2000 and February 2002, 315 patients were enrolled in the study. In Group 1 (201 patients) the common causes of hydrocephalus were myelomeningocele (16%), aqueductal stenosis (14%), and hemorrhage (14%). The overall 1-year shunt survival was 67%. Causes of shunt failure were obstruction (17%), overdrainage (1.5%), loculated ventricles (2%), and infection (10.6%). Patients in Group 2 (114 patients) were older and the causes of hydrocephalus were similar. Among patients in Group 2 the 1-year shunt survival was 71%. There were 256 valve adjustments. Symptoms completely resolved (26%) or improved (37%) after 63% of adjustments. When symptoms improved or resolved, they did so within 24 hours in 89% of adjustments. Hand-tool and radiographic readings of valve settings were the same in 234 (98%) of 238 assessments. Conclusions. The 1-year shunt survival for the Strata valve shunt system when used in initial shunt insertion procedures or shunt revisions was similar to those demonstrated for other valves. Symptom relief or improvement following adjustment was observed in 63% of patients. Hand-tool assessment of performance level settings reliably predicted radiographic assessments

    Juvenile pilocytic astrocytoma of the brainstem in children

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    Journal ArticleObject. In reports involving the operative treatment of brainstem tumors, multiple histological types are often grouped together. To determine prognosis after resection, histology-specific data may be helpful. Methods. Twenty-eight patients with juvenile pilocytic astrocytoma (JPA) of the brainstem (six in the midbrain, four in the pons, and 18 in the medulla) were identified from the medical records. Initial treatment was resection in 25 and biopsy sampling in three. Postoperative imaging revealed gross-total resection (GTR) or resection with linear enhancement (RLE) in 12 of 25 patients and solid residual tumor in the other 13. In 10 of the 13 patients harboring solid residual tumor, observation was undertaken; the residual lesion disappeared in one, was stable in four, and progressed in five. Of the 12 patients with complete excision or RLE only, seven underwent no further treatment, with tumor progression occurring in one. All patients were alive at last follow-up examination (range 0.3-20.4 years, mean 6 years). New neurological deficits commonly appeared immediately after resection but often resolved. In six of the 28 patients, the new postoperative deficit was still present at last follow-up visit. The 5- and 10-year progression-free survival was 74 and 62%, respectively, after GTR or RLE and 19 and 19%, respectively, when solid residual tumor was present. Conclusions. Long-term survival after resection of JPAs of the brainstem has been observed and appears to be related to the extent of initial excision

    Indicators of Resiliency Among Urban Elementary School Students At-Risk

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    This study was designed to investigate the phenomenon of resiliency among urban elementary school students in an at-risk environment. In contrast with previous studies narrowly focused upon the identification of risk factors, this study utilized a phenomenological qualitative approach to investigate indicators of resiliency from both individual and contextual perspectives. The narrative descriptions of 25 elementary school students in an at-risk environment were analyzed. The results indicated that the participants had strong individual and contextual resiliency indicators through the fifth grade despite being educated in a school district with almost a 60% drop-out rate before high school graduation

    Recommended Practice for Use of Faraday Probes in Electric Propulsion Testing

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143029/1/1.B35696.pd

    A Disk Shadow Around the Young Star ASR 41 in NGC 1333

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    We present images of the young stellar object ASR 41 in the NGC 1333 star forming region at the wavelengths of H_alpha and [SII] and in the I, J, H, and K-bands. ASR 41 has the near-infrared morphology of an edge-on disk object, but appears an order of magnitude larger than typical systems of this kind. We also present detailed models of the scattering and radiative transfer in systems consisting of a young star surrounded by a proto-planetary disk, and the whole system being embedded in either an infalling envelope or a uniform molecular cloud. The best fit to the observed morphology can be achieved with a disk of approx. 200 AU diameter, immersed in a low density cloud. The low cloud density is necessary to stay below the sub-mm flux upper limits and to preserve the shadow cast by the disk via single scattering. The results demonstrate that ASR 41 is probably not inherently different from typical edge-on disk objects, and that its large apparent size is due to the shadow of a much smaller disk being projected into the surrounding dusty molecular material

    HLA-Associated viral mutations are common in human immunodeficiency virus type 1 elite controllers

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    Elite controllers (EC) of human immunodeficiency virus type 1 (HTV-1) maintain viremia below the limit of detection without antiretroviral treatment. Virus-specific cytotoxic CD8+ T lymphocytes are believed to play a crucial role in viral containment, but the degree of immune imprinting and compensatory mutations in EC is unclear. We obtained plasma gag, pol, and nef sequences from HLA-diverse subjects and found that 30 to 40% of the predefined HLA-associated polymorphic sites show evidence of immune selection pressure in EC., compared to approximately 50% of the sites in chronic progressors. These data indicate ongoing viral replication and escape from cytotoxic T lymphocytes are present even in strictly controlled HTV-1 infection
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