1,214 research outputs found

    Some thoughts on IDRC's role in supporting rural development projects in Latin America

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    Discusses the meaning of agricultural development and various approaches to rural development; a seminar on the status of Puebla-type projects, based on technological change; the role of IDRC in the Caqueza project of ICA, with questions of research method, project evaluation, and staff training and future directions in IDRC

    Onset of Vortices in Thin Superconducting Strips and Wires

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    Spontaneous nucleation and the consequent penetration of vortices into thin superconducting films and wires, subjected to a magnetic field, can be considered as a nonlinear stage of primary instability of the current-carrying superconducting state. The development of the instability leads to the formation of a chain of vortices in strips and helicoidal vortex lines in wires. The boundary of instability was obtained analytically. The nonlinear stage was investigated by simulations of the time-dependent generalized Ginzburg-Landau equation.Comment: REVTeX 3.0, 12 pages, 5Postscript figures (uuencoded). Accepted for Phys. Rev.

    Coronal Temperature Diagnostic Capability of the Hinode/X-Ray Telescope Based on Self-Consistent Calibration

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    The X-Ray Telescope (XRT) onboard the Hinode satellite is an X-ray imager that observes the solar corona with unprecedentedly high angular resolution (consistent with its 1" pixel size). XRT has nine X-ray analysis filters with different temperature responses. One of the most significant scientific features of this telescope is its capability of diagnosing coronal temperatures from less than 1 MK to more than 10 MK, which has never been accomplished before. To make full use of this capability, accurate calibration of the coronal temperature response of XRT is indispensable and is presented in this article. The effect of on-orbit contamination is also taken into account in the calibration. On the basis of our calibration results, we review the coronal-temperature-diagnostic capability of XRT

    Mutations of the BRAF gene in human cancer

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    Cancers arise owing to the accumulation of mutations in critical genes that alter normal programmes of cell proliferation, differentiation and death. As the first stage of a systematic genome-wide screen for these genes, we have prioritized for analysis signalling pathways in which at least one gene is mutated in human cancer. The RAS RAF MEK ERK MAP kinase pathway mediates cellular responses to growth signals. RAS is mutated to an oncogenic form in about 15% of human cancer. The three RAF genes code for cytoplasmic serine/threonine kinases that are regulated by binding RAS. Here we report BRAF somatic missense mutations in 66% of malignant melanomas and at lower frequency in a wide range of human cancers. All mutations are within the kinase domain, with a single substitution (V599E) accounting for 80%. Mutated BRAF proteins have elevated kinase activity and are transforming in NIH3T3 cells. Furthermore, RAS function is not required for the growth of cancer cell lines with the V599E mutation. As BRAF is a serine/threonine kinase that is commonly activated by somatic point mutation in human cancer, it may provide new therapeutic opportunities in malignant melanoma

    Tests of the Equivalence Principle with Neutral Kaons

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    We test the Principle of Equivalence for particles and antiparticles, using CPLEAR data on tagged K0 and K0bar decays into pi^+ pi^-. For the first time, we search for possible annual, monthly and diurnal modulations of the observables |eta_{+-}| and phi_{+-}, that could be correlated with variations in astrophysical potentials. Within the accuracy of CPLEAR, the measured values of |eta_{+-}| and phi_{+-} are found not to be correlated with changes of the gravitational potential. We analyze data assuming effective scalar, vector and tensor interactions, and we conclude that the Principle of Equivalence between particles and antiparticles holds to a level of 6.5, 4.3 and 1.8 x 10^{-9}, respectively, for scalar, vector and tensor potentials originating from the Sun with a range much greater than the distance Earth-Sun. We also study energy-dependent effects that might arise from vector or tensor interactions. Finally, we compile upper limits on the gravitational coupling difference between K0 and K0bar as a function of the scalar, vector and tensor interaction range.Comment: 15 pages latex 2e, five figures, one style file (cernart.csl) incorporate

    Variants in CHEK2 other than 1100delC do not make a major contribution to breast cancer susceptibility

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    We recently reported that a sequence variant in the cell-cycle-checkpoint kinase CHEK2 (CHEK2 1100delC) is a low-penetrance breast cancer-susceptibility allele in noncarriers of BRCA1 or BRCA2 mutations. To investigate whether other CHEK2 variants confer susceptibility to breast cancer, we screened the full CHEK2 coding sequence in BRCA1/2-negative breast cancer cases from 89 pedigrees with three or more cases of breast cancer. We identified one novel germline variant, R117G, in two separate families. To evaluate the possible association of R117G and two germline variants repo

    Test of CPT Symmetry and Quantum Mechanics with Experimental data from CPLEAR

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    We use fits to recent published CPLEAR data on neutral kaon decays to π+π−\pi^+\pi^- and πeÎœ\pi e\nu to constrain the CPT--violation parameters appearing in a formulation of the neutral kaon system as an open quantum-mechanical system. The obtained upper limits of the CPT--violation parameters are approaching the range suggested by certain ideas concerning quantum gravity.Comment: 9 pages of uuencoded postscript (includes 3 figures

    Living with persistent pain: experiences of older people receiving home care.

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    Background. Although the topic of pain among older people has received increasing interest, little is still known about how pain is experienced or handled by those who no longer manage independently but depend on professionals for help with daily living. Developing pain management for older people requires such knowledge. Aim. To explore sense of self, sense of pain, daily living with pain, sense of others and ways of handling pain in older people with persistent pain. Methods. Interviews with 90 older people receiving home care from nursing auxiliaries in their own homes or in sheltered accommodation were collected from January to June 2000. A typology of older people in persistent pain was developed. Activities for handling pain were examined using content analysis. Findings. Respondents' experiences of themselves and their pain varied. Two groups of older people, considered as 'competent and proud' and 'confident and serene', expressed satisfaction in spite of pain, while the groups 'misunderstood and disappointed' and 'resigned and sad' expressed dissatisfaction. The most common strategies used were medication, rest, mobility, distracting activities and talking about pain. Respondents chose strategies by balancing the advantages of the activities against the disadvantages these brought for their daily living. Conclusion. This study indicates that characteristics of the older people, such as their way of experiencing themselves, how pain affects their daily life and how they perceive effects and side-effects of pain management are areas that need to be identified when staff assess pain and plan pain management. Caring for older people in pain could be improved by listening to and believing their complaints, evaluating effects and side-effects from medications and nonpharmacological pain management and by emphasising the importance of common everyday activities such as mobility and distraction to relieve pain

    Measurement of the W+W-gamma Cross Section and Direct Limits on Anomalous Quartic Gauge Boson Couplings at LEP

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    The process e+e- -> W+W-gamma is analysed using the data collected with the L3 detector at LEP at a centre-of-mass energy of 188.6GeV, corresponding to an integrated luminosity of 176.8pb^-1. Based on a sample of 42 selected W+W- candidates containing an isolated hard photon, the W+W-gamma cross section, defined within phase-space cuts, is measured to be: sigma_WWgamma = 290 +/- 80 +/- 16 fb, consistent with the Standard Model expectation. Including the process e+e- -> nu nu gamma gamma, limits are derived on anomalous contributions to the Standard Model quartic vertices W+W- gamma gamma and W+W-Z gamma at 95% CL: -0.043 GeV^-2 < a_0/Lambda^2 < 0.043 GeV^-2 0.08 GeV^-2 < a_c/Lambda^2 < 0.13 GeV^-2 0.41 GeV^-2 < a_n/Lambda^2 < 0.37 GeV^-2

    Production of Single W Bosons at \sqrt{s}=189 GeV and Measurement of WWgamma Gauge Couplings

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    Single W boson production in electron-positron collisions is studied with the L3 detector at LEP. The data sample collected at a centre-of-mass energy of \sqrt{s} = 188.7GeV corresponds to an integrated luminosity of 176.4pb^-1. Events with a single energetic lepton or two acoplanar hadronic jets are selected. Within phase-space cuts, the total cross-section is measured to be 0.53 +/- 0.12 +/- 0.03 pb, consistent with the Standard Model expectation. Including our single W boson results obtained at lower \sqrt{s}, the WWgamma gauge couplings kappa_gamma and lambda_gamma are determined to be kappa_gamma = 0.93 +/- 0.16 +/- 0.09 and lambda_gamma = -0.31 +0.68 -0.19 +/- 0.13
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