793 research outputs found

    Population structure of a deep-water squaloid shark, the Portuguese dogfish (Centroscymnus coelolepis)

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    The genetic population structure of the deep-water squaloid Centroscymnus coelolepis (the Portuguese dogfish) in the eastern Atlantic was investigated using eight polymorphic nuclear microsatellite markers and a 496-bp fragment of the mitochondrial DNA control region (mtDNA CR). Samples (20-50 individuals per location) were collected off Ireland, Portugal, Madeira, Mauritania, South Africa, and the Azores (Mid-Atlantic Ridge). High levels of genetic diversity were found at the nuclear microsatellite loci (mean A = 17.3; overall H(o) = 0.77), although there was low diversity at the mtDNA CR (h = 0.65, pi = 0 0.0018). Genetic diversity for the Portuguese dogfish was homogeneously distributed among sampling locations, resulting in low and non-significant indices of genetic differentiation (e.g. F(ST) -0013 to 0.0096, Phi(ST) = -0.017 to 0.033; p \u3e 0.5), consistent with the absence of population structure within the area sampled. The results indicate that C. coelolepis has a high dispersal potential within the eastern Atlantic, and its apparent spatial segregation by size and maturity stage suggest large-scale migration associated with the reproductive cycle

    Measuring Returns to Hospital Care: Evidence from Ambulance Referral Patterns

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    We consider whether hospitals that receive higher payments from Medicare improve patient outcomes, using exogenous variation in ambulance company assignment among patients who live near one another. Using Medicare data from 2002–10 on assignment across ambulance companies and New York State data from 2000–6 on assignment across area boundaries, we find that patients who are brought to higher-cost hospitals achieve better outcomes. Our estimates imply that a one standard deviation increase in Medicare reimbursement leads to a 4 percentage point (or 10 percent) reduction in mortality; the implied cost per at least 1 year of life saved is approximately $80,000.National Institutes of Health (U.S.) (R01 AG41794-01

    The Advancement of Humans in Space

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    The advancement of humans into space and potentially beyond started slow but has greatly increased in speed over the past 2 generations. NASA has been at the forefront of this development and coontinues to lead the way into space exploration. This presentation provides a brief historical overview of NASA's space exploration efforts and touches on the abilityof each new generation to greatly expand our presence in space

    A new approach to ensuring oral health care for people living with HIV/AIDS: the dental case manager

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    INTRODUCTION: The American Dental Association has identified several barriers to adequate dental care for vulnerable populations, including appropriate case management. The objective of this study was to examine the perceptions, attitudes, and beliefs of dental patients living with HIV/AIDS on the role and value of the dental case manager (DCM) and the effect of DCM services on their oral or overall health. METHODS: We used a qualitative descriptive study design and focus groups. Twenty-five people who had received DCM services on Cape Cod, Massachusetts, attended 1 of 5 focus groups in 2009 and 2010. Digital recordings of the groups were transcribed verbatim. Textual data were categorized using directed qualitative content analysis techniques. We identified major themes and representative quotes. RESULTS: The following themes emerged from discussions on the DCM\u27s role: being available, knowledgeable about clients and insurance, and empathetic; increasing access; and providing comfort. Most participants credited their oral and overall health improvements to the DCM. All participants believed that the DCM was a valuable addition to the clinic and noted that other at-risk populations, including the elderly and developmentally disabled, likely would benefit from working with a DCM. CONCLUSION: The addition of a DCM facilitated access to dental care among this sample of people living with HIV/AIDS, providing them with an advocate and resulting in self-reported improvements to oral and overall health

    The 3′ end of the heavy chain constant region locus enhances germline transcription and switch recombination of the four γ genes

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    The switch in immunoglobulin (Ig) heavy chain class is preceded by germline transcription and then mediated by a DNA recombination event. To study germline transcription and class switch recombination we used transgenic mice with a 230-kilobase bacterial artificial chromosome that included a rearranged VDJ gene and the entire heavy chain constant region locus. In addition to several lines with intact transgenes, we identified two lines in which the heavy chain locus transgene lacked Cα and everything 3′ of it, including the regulatory elements HS3a, HS1-2, HS3b, and HS4. B cells from both lines with the truncated transgenes make abundant transgenic (Tg) VDJCμ transcripts and IgM protein. Deletion of the 3′ end of the locus results in dramatically reduced expression of both germline transcripts and switched VDJCH transcripts of the γ3, γ2b, γ2a, and ɛ genes. In addition, the transgenes lacking the 3′ end of the locus express reduced amounts of γ1 germline transcripts and 2–3% of the amount of Tg IgG1 in tissue culture compared with intact transgenes. Finally, switch recombination to γ1 is undetectable in the transgenes lacking the 3′ elements, as measured by digestion circularization–polymerase chain reaction or by the expression of VDJCγ1 transcripts

    Effect of suspension systems on the physiological and psychological responses to sub-maximal biking on simulated smooth and bumpy tracks

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    The aim of this study was to compare the physiological and psychological responses of cyclists riding on a hard tail bicycle and on a full suspension bicycle. Twenty males participated in two series of tests. A test rig held the front axle of the bicycle steady while the rear wheel rotated against a heavy roller with bumps (or no bumps) on its surface. In the first series of tests, eight participants (age 19 – 27 years, body mass 65 – 82 kg) were tested on both the full suspension and hard tail bicycles with and without bumps fitted to the roller. The second series of test repeated the bump tests with a further six participants (age 22 – 31 years, body mass 74 – 94 kg) and also involved an investigation of familiarization effects with the final six participants (age 21 – 30 years, body mass 64 – 80 kg). Heart rate, oxygen consumption (VO<sub>2</sub>), rating of perceived exertion (RPE) and comfort were recorded during 10 min sub-maximal tests. Combined data for the bumps tests show that the full suspension bicycle was significantly different (P < 0.001) from the hard tail bicycle on all four measures. Oxygen consumption, heart rate and RPE were lower on average by 8.7 (s = 3.6) ml · kg<sup>-1</sup> · min<sup>-1</sup>, 32.1 (s = 12.1) beats · min<sup>-1</sup> and 2.6 (s = 2.0) units, respectively. Comfort scores were higher (better) on average by 1.9 (s = 0.8) units. For the no bumps tests, the only statistically significant difference (P = 0.008) was in VO<sub>2</sub>, which was lower for the hard tail bicycle by 2.2 (s = 1.7) ml · kg-1 · min<sup>-1</sup>. The results indicate that the full suspension bicycle provides a physiological and psychological advantage over the hard tail bicycle during simulated sub-maximal exercise on bumps

    Mars Exploration Rover Flight Operations Technical Consultation

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    The Mars Exploration Rover (MER) Project at the Jet Propulsion Laboratory developed two golf-cart size robotic vehicles, Spirit and Opportunity, for geological exploration of designated target areas on the surface of Mars. The primary scientific objective of these missions was the search for evidence of the presence of water on or near the surface of the planet during its history. Spirit and Opportunity were launched on June 10 and July 7, 2003, with their respective landings scheduled for January 4 and January 25, 2004 (UTC). NASA views the MER missions as particularly critical because of their scientific importance in the ongoing search for conditions under which life might have existed elsewhere in the solar system, because of their high level of public interest and because more than half of all prior missions launched to Mars internationally have failed. This report summarizes the findings and recommendations of the NASA Engineering and Safety Center review of the project

    Impacts of the Extended-Weight Coal Haul Road System

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    The Extended-Weight Coal Haul Road System, created by the Kentucky Legislature in 1986, consists of all roads which carry over 50,000 tons of coal in a calendar year. Trucks hauling coal on this system are authorized to exceed normal weight limits through the payment of an annual decal fee. A research study was initiated in July of 1992 to analyze the impacts of the extended-weight system. Analyses in this report are based on the following: historical data on coal production and transportation: data from coal decal applications; interviews of legislators. transportation officials. coal company representatives. and coal trucking representatives: newspaper articles; vehicle classification data: analyses of pavement costs: pavement rideability data; and accident data. Primary conclusions include: I) The extended-weight 5)\u27Stem has apparently been somewhat successful in accomplishing the objective of enhancing the competitiveness and economic viability of the Kentucky coal industry; 2) Overall accident rates did not increase as a result of implementation of the extended-weight system. but the fatal accident injury rates were significantly higher on the extended-weight system and for trucks operating with the coal decal; 3) Advance-warning flashers have been evaluated and recommended as a means of reducing intersection accidents involving heavy/coal trucks; 4) The coal-decal fee structure results in a net annual loss in Road Fund revenue of approximately S2 million; 5) Forty percent of revenue from decal fees are allocated to counties even though county-maintained roads comprise only eight percent of the extended-weight system; 6) Heavier weights of coal-decal trucks add approximately $9 million annually to the pavement overlay costs; 7) Road users throughout the state are subsidizing the movement of Kentucky coal by participating in the cost of maintaining and improving tile highway system; and 8) Possibly reflecting the increased funding of extended-weight roads., the rideability index. has risen to a level above the statewide average. The primary recommendation was that the extended-weight system should evolve into a comprehensive trucking network. A Resource and Commodity Highway System was evaluated as a separate study and found to be a feasible and desirable means of providing a trucking highway network that is fully compatible with the dimensions and characteristics of large trucks
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