3,188 research outputs found

    Changes in Management Can Improve Returns from Cambodian Upland Crops

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    Farming systems research for wet-season non-rice upland crops in Cambodia is being conducted with the overall aim of poverty reduction and food security for farmers in the Provinces of Battambang and Kampong Cham. Some of these cash crops exhibit low and variable incomes, especially when grown in the early wet season. Cambodian farmers may borrow money to buy crop inputs and often sell their produce to companies and traders from neighbouring countries, hence they are price takers. Some new crop technologies are evaluated which relate to soil and crop fertility management interacting with climatic factors. The DSSAT crop simulation model is used to predict outcomes from alternative management strategies. Bio-economic analyses are conducted to assess the likely appeal of these technologies to Cambodian farmers in a return-on-investment context. The results show that management to adjust the nitrogen fertility available to corn, the use of rhizobium in soybean, and a delay in planting early-wet-season corn may all show substantial financial benefits. Further research and an associated farmer demonstration program involving local extension officers are recommended.Upland crops, Cambodia, technology, economics, simulation, risk, Crop Production/Industries,

    The Green Zone Initiative: Combining Virtual and Face-to-Face Training to Support Veterans in Higher Education

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    The purpose of the Green Zone Initiative is to address the needs of the nearly 700 student Veterans at a state comprehensive university who are enrolled either on campus or online. The number of service members reintegrating into civilian life is higher than at any time in history since the Vietnam War. As Traumatic Brain Injury is the signature wound of this war, Post-Traumatic Stress Disorder, as well as the civilian-military divide are all having a monumental impact on our veteran population across America. Student Veterans re-entering civilian life and adjusting to college are under additional pressures which place them in a category of students who may need additional resources and supports to be successful. The purpose of the Green Zone Initiative is to educate and equip faculty and staff to identify those needs and provide support and direction to those resources

    Sealing in Turbomachinery

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    Clearance control is of paramount importance to turbomachinery designers and is required to meet today's aggressive power output, efficiency, and operational life goals. Excessive clearances lead to losses in cycle efficiency, flow instabilities, and hot gas ingestion into disk cavities. Insufficient clearances limit coolant flows and cause interface rubbing, overheating downstream components and damaging interfaces, thus limiting component life. Designers have put renewed attention on clearance control, as it is often the most cost effective method to enhance system performance. Advanced concepts and proper material selection continue to play important roles in maintaining interface clearances to enable the system to meet design goals. This work presents an overview of turbomachinery sealing to control clearances. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues

    The effects of nocturnal hemodialysis compared to conventional hemodialysis on change in left ventricular mass: Rationale and study design of a randomized controlled pilot study

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    BACKGROUND: Nocturnal hemodialysis (NHD) is an alternative to conventional three times per week hemodialysis (CvHD) and has been reported to improve several health outcomes. To date, no randomized controlled trial (RCT) has compared NHD and CvHD. We have undertaken a multi-center RCT in hemodialysis patients comparing the effect of NHD to CvHD on left ventricular (LV) mass, as measured by cardiac magnetic resonance imaging (cMR). METHODOLOGY/DESIGN: All patients in Alberta, Canada, expressing an interest in performing NHD are eligible for the study. Patients enrolled in the study will be randomized to either NHD or CvHD for a six month period. All patients will have a full clinical assessment, including collection of biochemical and cMR data at baseline and at 6 months. Both groups of patients will be monitored biweekly to optimize blood pressure (BP) to a goal of <130/80 mmHg post-dialysis using a predefined BP management protocol. The primary outcome is change in LV mass, a surrogate marker for cardiac mortality, measured at baseline and 6 months. The high sensitivity and reproducibility of cMR facilitates reduction of the required sample size and the time needed between measures compared with echocardiography. Secondary outcomes include BP control, anemia, mineral metabolism, health-related quality of life, and costs. DISCUSSION: To our knowledge, this study will be the first RCT evaluating health outcomes in NHD. The impact of NHD on LV mass represents a clinically important outcome which will further elucidate the potential benefits of NHD and guide future clinical endpoint studies

    Artemin Is a Vascular-Derived Neurotropic Factor for Developing Sympathetic Neurons

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    AbstractArtemin (ARTN) is a member of the GDNF family of ligands and signals through the Ret/GFRα3 receptor complex. Characterization of ARTN- and GFRα3-deficient mice revealed similar abnormalities in the migration and axonal projection pattern of the entire sympathetic nervous system. This resulted in abnormal innervation of target tissues and consequent cell death due to deficiencies of target-derived neurotrophic support. ARTN is expressed along blood vessels and in cells nearby to sympathetic axonal projections. In the developing vasculature, ARTN is expressed in smooth muscle cells of the vessels, and it acts as a guidance factor that encourages sympathetic fibers to follow blood vessels as they project toward their final target tissues. The chemoattractive properties of ARTN were confirmed by the demonstration that sympathetic neuroblasts migrate and project axons toward ARTN-soaked beads implanted into mouse embryos

    Decrease in natural marine hydrocarbon seepage near Coal Oil Point, California, associated with offshore oil production

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    Prolific natural hydrcarbon seepage occurs offshore of Coal Oil Point in the Santa Barbara Channel, California. Within the water column above submarine vents, plumes of hydrocarbon gas bubbles act as acoustic scattering targets. Using 3.5 kHz sonar data, seep distribution offshore of Coal Oil Point was mapped for August 1996, July 1995, and July 1973. Comparison of the seep distributions over time reveals more than 50% decrease in the areal extent of seepage, accompanied by declines in seep emission volume, in a 13 km2 area above a production oil reservoir. Declines in reservoir pressure and depletion of seep hydrocarbon sources associated with oil production are the mechanisms inferred to explain the declines in seep and emission volume

    Turbomachinery Clearance Control

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    Controlling interface clearances is the most cost effective method of enhancing turbomachinery performance. Seals control turbomachinery leakages, coolant flows and contribute to overall system rotordynamic stability. In many instances, sealing interfaces and coatings are sacrificial, like lubricants, giving up their integrity for the benefit of the component. They are subjected to abrasion, erosion, oxidation, incursive rubs, foreign object damage (FOD) and deposits as well as extremes in thermal, mechanical, aerodynamic and impact loadings. Tribological pairing of materials control how well and how long these interfaces will be effective in controlling flow. A variety of seal types and materials are required to satisfy turbomachinery sealing demands. These seals must be properly designed to maintain the interface clearances. In some cases, this will mean machining adjacent surfaces, yet in many other applications, coatings are employed for optimum performance. Many seals are coating composites fabricated on superstructures or substrates that are coated with sacrificial materials which can be refurbished either in situ or by removal, stripping, recoating and replacing until substrate life is exceeded. For blade and knife tip sealing an important class of materials known as abradables permit blade or knife rubbing without significant damage or wear to the rotating element while maintaining an effective sealing interface. Most such tip interfaces are passive, yet some, as for the high-pressure turbine (HPT) case or shroud, are actively controlled. This work presents an overview of turbomachinery sealing. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues
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