2,356 research outputs found

    Growth and characterization of materials for tunable lasers in the near infrared spectral region

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    During this reporting period, work proceeded in two directions. The first was the development of crystal growth procedures for rare earth doped LiYF4 crystals. The procedures for growth and pre-growth treatment of starting materials for undoped LiYF4 crystals were established and good optical quality materials were grown. A significant amount of time was spent trying to establish the optimum growth parameters for Yb(3+)-doped crystals. Unfortunately, it has proven difficult to obtain large size boules of high optical quality crystals of LiYF4 with doping concentrations of Yb(3+) of several percent. Because of these problems, this research is to be changed to attempt doping with other trivalent rare earth ions such as Ho, Er, and Tm. The second research area was investigating the potential of LiNbO3:Mg,Cr and LiNbO3:Mg,Cr,Yb as possible laser materials. The results are summarized

    Analysis of the staging maneuver and booster glideback guidance for a two-stage, winged, fully reusable launch vehicle

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    One of the promising launch concepts that could replace the current space shuttle launch system is a two-stage, winged, vertical-takeoff, fully reusable launch vehicle. During the boost phase of ascent, the booster provides propellant for the orbiter engines through a cross-feed system. When the vehicle reaches a Mach number of 3, the booster propellants are depleted and the booster is staged and glides unpowered to a horizontal landing at a launch site runway. Two major design issues for this class of vehicle are the staging maneuver and the booster glideback. For the staging maneuver analysis, a technique was developed that provides for a successful separation of the booster from the orbiter over a wide range of staging angles of attack. A longitudinal flight control system was developed for control of the booster during the staging maneuver. For the booster glide back analysis, a guidance algorithm was developed that successfully guides the booster from the completion of the staging maneuver to a launch site runway while encountering many off-nominal atmospheric, aerodynamic, and staging conditions

    Growth and characterization of tunable solid state lasers in the near infrared spectral region

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    This research resulted in the publication of two major papers. The major results include the development of improved crystal growth techniques for rare earth-doped LiYF4 crystals and the determination of laser-pumped laser characteristics of Tm:Ho:Y3Al5O12 crystals

    Cleaning House? Assessing the Impact of Maine’s Clean Elections Act on Electoral Competitiveness

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    Does full public financing of legislative elections make races more competitive? Richard Powell analyzes the impact of the Maine Clean Elections Act (MCEA) on Maine House and Senate elections since its passage in 2000. Using statistical analysis, he concludes the MCEA has not significantly increased competitiveness, even though candidates have been able to rely substantially less on private contributions and the financial disparity between candidates has decreased significantly. Powell suggests that analysis of the Maine case will be useful as the nation and other states consider public-financing laws compa­rable to the MCEA

    Flesh on the Bones: Animal Bodies in Atlantic Roundhouses

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    This volume presents the state of research across Europe to illustrate how comparable interpretative frameworks are used by archaeologists working with both prehistoric and historical societies

    PEPFAR Public Health Evaluation-Care and Support -Phase I Kenya

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    Phase 1, a survey of 120 care facilities in Kenya and Uganda, found that over 90% of facilities provided some level of clinical, psychological,and preventive care. Pain control was very limited with paracetamol often the only analgesic. In focus group discussions, patients appreciated free care and positive attitudes from staff, but said that services would be improved by more staff, shorter queues, and reliable drug supplies

    A note on the use of FTA™ technology for storage of blood samples for DNA analysis and removal of PCR inhibitors

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    peer-reviewedFTA™ technology is widely used across many molecular disciplines for sample capture, storage and analysis. The use of this technology for the long-term storage of blood samples for DNA analysis was examined as well as its potential to remove inhibitors from DNA samples previously extracted from blood with PCR inhibitors remaining. It was found that blood spots stored on FTA™ cards for 8 years at room temperature gave successful PCR products and that FTA™ cards are a useful tool for removing substances in samples which interfere with or inhibit, the PCR reaction

    Investigation of Prolific Sheep from UK and Ireland for Evidence on Origin of the Mutations in BMP15 (FecXG, FecXB) and GDF9 (FecGH) in Belclare and Cambridge Sheep

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    peer-reviewedThis paper concerns the likely origin of three mutations with large effects on ovulation rate identified in the Belclare and Cambridge sheep breeds; two in the BMP15 gene (FecXG and FecXB) and the third (FecGH) in GDF9. All three mutations segregate in Belclare sheep while one, FecXB, has not been found in the Cambridge. Both Belclare and Cambridge breeds are relatively recently developed composites that have common ancestry through the use of genetic material from the Finnish Landrace and Lleyn breeds. The development of both composites also involved major contributions from exceptionally prolific ewes screened from flocks in Ireland (Belclare) and Britain (Cambridge) during the 1960s. The objective of the current study was to establish the likely origin of the mutations (FecXG, FecXB and FecGH) through analysis of DNA from Finnish Landrace and Lleyn sheep, and Galway and Texel breeds which contributed to the development of the Belclare breed. Ewes with exceptionally high prolificacy (hyper-prolific ewes) in current flocks on Irish farms were identified to simulate the screening of ewes from Irish flocks in the 1960s. DNA was obtained from: prolific ewes in extant flocks of Lleyn sheep (n = 44) on the Lleyn peninsula in Wales; hyper-prolific ewes (n = 41); prolific Galway (n = 41) ewes; Finnish Landrace (n = 124) and Texel (n = 19) ewes. The FecXG mutation was identified in Lleyn but not in Finnish Landrace, Galway or Texel sheep; FecXB was only found among the hyper-prolific ewes. The FecGH mutation was identified in the sample of Lleyn sheep. It was concluded from these findings that the Lleyn breed was the most likely source of the FecXG and FecGH mutations in Belclare and Cambridge sheep and that the FecXB mutation came from the High Fertility line that was developed using prolific ewes selected from commercial flocks in Ireland in the 1960′s and subsequently used in the genesis of the Belclare.Financial support through the Teagasc Walsh Fellowship Scheme, Genesis Faraday SPARK award (Lleyn survey) and Science Foundation Ireland (07/SRC/B1156) is gratefully acknowledged

    PEPFAR Public Health Evaluation -Care and Support -Phase I Uganda

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    Phase 1, a survey of 120 care facilities in Kenya and Uganda, found that over 90% of facilities provided some level of clinical, psychological,and preventive care. Pain control was very limited with paracetamol often the only analgesic. In focus group discussions, patients appreciated free care and positive attitudes from staff, but said that services would be improved by more staff, shorter queues, and reliable drug supplies
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