316 research outputs found

    Update of Parton Distributions at NNLO

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    We present a new set of parton distributions obtained at NNLO. These differ from the previous sets available at NNLO due to improvements in the theoretical treatment. In particular we include a full treatment of heavy flavours in the region near the quark mass. In this way, an essentially complete set of NNLO partons is presented for the first time. The improved treatment leads to a significant change in the gluon and heavy quark distributions, and a larger value of the QCD coupling at NNLO, alpha_S(M_Z^2) = 0.1191 +/- 0.002(expt.) +/- 0.003(theory). Indirectly this also leads to a change in the light partons at small x and modifications of our predictions for W and Z production at the LHC. As well as the best-fit set of partons, we also provide 30 additional sets representing the uncertainties of the partons obtained using the Hessian approach.Comment: 13 pages, 11 figures. Version published. Slight extension and some modification of reference

    Transfer of brightness discrimination under unilateral spreading depression

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    Rats trained under unilateral cortical spreading depression on a brightness discrimination task for water reinforcement will show little or no transfer when retrained with the contralateral cortex depressed. The current study was performed in order to determine if the degree of transfer can be affected by reinforcement or motivational variables. Rats were trained on a brightness discrimination task to either escape or avoid painful foot shock. The animals trained to escape showed nearly perfect transfer. The animals trained to avoid showed very little transfer of the avoidance response but did transfer the brightness discrimination. It was concluded that in the unilateral spreading depression paradigm the degree of transfer obtained on similar tasks is altered by changing the reinforcement.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32913/1/0000293.pd

    The quantitative soil pit method for measuring belowground carbon and nitrogen stocks

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    Many important questions in ecosystem science require estimates of stocks of soil C and nutrients. Quantitative soil pits provide direct measurements of total soil mass and elemental content in depth-based samples representative of large volumes, bypassing potential errors associated with independently measuring soil bulk density, rock volume, and elemental concentrations. The method also allows relatively unbiased sampling of other belowground C and nutrient stocks, including roots, coarse organic fragments, and rocks. We present a comprehensive methodology for sampling these pools with quantitative pits and assess their accuracy, precision, effort, and sampling intensity as compared to other methods. At 14 forested sites in New Hampshire, nonsoil belowground pools (which other methods may omit, double-count, or undercount) accounted for upward of 25% of total belowground C and N stocks: coarse material accounted for 4 and 1% of C and N in the O horizon; roots were 11 and 4% of C and N in the O horizon and 10 and 3% of C and N in the B horizon; and soil adhering to rocks represented 5% of total B-horizon C and N. The top 50 cm of the C horizon contained the equivalent of 17% of B-horizon carbon and N. Sampling procedures should be carefully designed to avoid treating these important pools inconsistently. Quantitative soil pits have fewer sources of systematic error than coring methods; the main disadvantage is that because they are time-consuming and create a larger zone of disturbance, fewer observations can be made than with cores

    The functional neuroanatomy resource (FNAR) at Weill Cornell Medicine

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    INTRODUCTION. Computer assisted instruction has long proven useful in teaching of neuroanatomy, particularly when accompanied by traditional lecture presentations that present image and text data to students. The work describes the functional neuroanatomy resource (FNAR) innovation created at Weill Cornell Medicine – the first homegrown functional neuroanatomy teaching application developed for iPads by a medical school, including the learning options actively utilized by students and plans for continued development of the app. RESOURCES. Previously the teaching of functional neuroanatomy has relied heavily on gross brain and histological material created at the medical college and presented through computer technology initially server-based and then web-based. When the institution decided to move students to mobile devices, all students were provided with iPads. The functional neuroanatomy faculty and educational computing team accepted the challenge to make the FNAR content available through an iPad app. DESCRIPTION. This first local FNAR app integrates and indexes an image database along with various text resources. The app utilizes mouse-over and overlay technology, allowing users to easily highlight and select different areas of the brain and spinal cord and their related structures; it allows students to access the self-assessment tools onto the image overlays so that students can test their knowledge as they progress. CONCLUSIONS. A recent student evaluation reflects students rating the overall quality and usefulness of the FNAR as “excellent” (3.85 on a 4-point scale). Future plans include incorporating radiographic images and an “on-the-fly image set” technology, allowing students to query the database specifically designed to answer their questions

    Fear of the unknown: a pre-departure qualitative study of Turkish international students

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    This paper presents findings from eleven in-depth interviews with Turkish undergraduate students, who were, by the time of data collection, about to spend a semester at a European university under the Erasmus exchange scheme. The students all agreed to be interviewed about their feelings about studying in a foreign culture, and were found to be anxious prior to departure about the quality of accommodation in the new destination, their language ability and the opportunity to form friendships. Fears were expressed about possible misconceptions over Turkey as a Muslim and a developing country. Suggestions are made for HEI interventions to allay student travellers’ concerns

    Physical activity measured by accelerometry and its associations with cardiac structure and vascular function in young and middle-aged adults

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    Background Physical activity is associated with several health benefits, including lower cardiovascular disease risk. The independent influence of physical activity on cardiac and vascular function in the community, however, has been sparsely investigated. Measures and Results We related objective measures of moderate‐ to vigorous‐intensity physical activity (MVPA, assessed by accelerometry) to cardiac and vascular indices in 2376 participants of the Framingham Heart Study third generation cohort (54% women, mean age 47 years). Using multivariable regression models, we related MVPA to the following echocardiographic and vascular measures: left ventricular mass, left atrial and aortic root sizes, carotid–femoral pulse wave velocity, augmentation index, and forward pressure wave. Men and women engaged in MVPA 29.9±21.4 and 25.5±19.4 min/day, respectively. Higher values of MVPA (per 10‐minute increment) were associated with lower carotid–femoral pulse wave velocity (estimate −0.53 ms/m; P=0.006) and lower forward pressure wave (estimate −0.23 mm Hg; P=0.03) but were not associated with augmentation index (estimate 0.13%; P=0.25). MVPA was associated positively with loge left ventricular mass (estimate 0.006 loge [g/m2]; P=0.0003), left ventricular wall thickness (estimate 0.07 mm; P=0.0001), and left atrial dimension (estimate 0.10 mm; P=0.01). MVPA also tended to be positively associated with aortic root dimension (estimate 0.05 mm; P=0.052). Associations of MVPA with cardiovascular measures were similar, in general, for bouts lasting <10 versus ≄10 minutes. Conclusions In our community‐based sample, greater physical activity was associated with lower vascular stiffness but with higher echocardiographic left ventricular mass and left atrial size. These findings suggest complex relations of usual levels of physical activity and cardiovascular remodeling
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