10,459 research outputs found

    Molecular Diagnostics in the Mycosphaerella Leaf Spot Disease Complex of Banana and for Radopholus similis

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    Mycosphaerella leaf spots and nematodes threaten banana cultivation worldwide. The Mycosphaerella disease complex involves three related ascomycetous fungi: Mycosphaerella fijiensis, M. musicola and M. eumusae. The exact distribution of these three species and their disease epidemiology remain unclear, since their symptoms and life cycles are rather similar. Diagnosing these diseases and the respective causal agents is based on the presence of host symptoms and fungal fruiting structures, but is time consuming and not conducive to preventive management. In the present study, we developed rapid and robust species-specific diagnostic tools to detect and quantify M. fijiensis, M. musicola and M. eumusae. Conventional species-specific PCR primers were developed based on the actin gene that detected as little as 100, 1 and 10 pg/µl DNA from, respectively, M. fijiensis, M. musicola and M. eumusae. Furthermore, TaqMan real-time quantitative PCR assays that were developed based on the ß-tubulin gene detected quantities as low as 1 pg/µl DNA of each species from pure cultures and 1.6 pg/µl DNA/mg of M. fijiensis from dry leaf tissue. The efficacy of the tests was validated using naturally infected banana leaves. Similar technology has been used to develop a quantitative PCR assay for the banana burrowing nematode, Radopholus similis, which is currently being validate

    Nuclear medium effects in ν(νˉ)\nu(\bar\nu)-nucleus deep inelastic scattering

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    We study the nuclear medium effects in the weak structure functions F2(x,Q2)F_2(x,Q^2) and F3(x,Q2)F_3(x,Q^2) in the deep inelastic neutrino/antineutrino reactions in nuclei. We use a theoretical model for the nuclear spectral functions which incorporates the conventional nuclear effects, such as Fermi motion, binding and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. The calculations have been performed using relativistic nuclear spectral functions which include nucleon correlations. Our results are compared with the experimental data of NuTeV and CDHSW.Comment: 24 pages, 14 figure

    Scaling of spontaneous rotation with temperature and plasma current in tokamaks

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    Using theoretical arguments, a simple scaling law for the size of the intrinsic rotation observed in tokamaks in the absence of momentum injection is found: the velocity generated in the core of a tokamak must be proportional to the ion temperature difference in the core divided by the plasma current, independent of the size of the device. The constant of proportionality is of the order of 10kms1MAkeV110\,\mathrm{km \cdot s^{-1} \cdot MA \cdot keV^{-1}}. When the intrinsic rotation profile is hollow, i.e. it is counter-current in the core of the tokamak and co-current in the edge, the scaling law presented in this Letter fits the data remarkably well for several tokamaks of vastly different size and heated by different mechanisms.Comment: 5 pages, 3 figure

    Long Term Variability of SDSS Quasars

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    We use a sample of 3791 quasars from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), and compare their photometry to historic plate material for the same set of quasars in order to study their variability properties. The time base-line we attain this way ranges from a few months to up to 50 years. In contrast to monitoring programs, where relatively few quasars are photometrically measured over shorter time periods, we utilize existing databases to extend this base-line as much as possible, at the cost of sampling per quasar. Our method, however, can easily be extended to much larger samples. We construct variability Structure Functions and compare these to the literature and model functions. From our modeling we conclude that 1) quasars are more variable toward shorter wavelengths, 2) their variability is consistent with an exponentially decaying light-curve with a typical time-scale of ~2 years, 3) these outbursts occur on typical time-scales of ~200 years. With the upcoming first data release of the SDSS, a much larger quasar sample can be used to put these conclusions on a more secure footing.Comment: 16 pages, accepted for publication in AJ, Sept issu

    Field-Dependent Tilt and Birefringence of Electroclinic Liquid Crystals: Theory and Experiment

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    An unresolved issue in the theory of liquid crystals is the molecular basis of the electroclinic effect in the smectic-A phase. Recent x-ray scattering experiments suggest that, in a class of siloxane-containing liquid crystals, an electric field changes a state of disordered molecular tilt in random directions into a state of ordered tilt in one direction. To investigate this issue, we measure the optical tilt and birefringence of these liquid crystals as functions of field and temperature, and we develop a theory for the distribution of molecular orientations under a field. Comparison of theory and experiment confirms that these materials have a disordered distribution of molecular tilt directions that is aligned by an electric field, giving a large electroclinic effect. It also shows that the net dipole moment of a correlated volume of molecules, a key parameter in the theory, scales as a power law near the smectic-A--smectic-C transition.Comment: 18 pages, including 9 postscript figures, uses REVTeX 3.0 and epsf.st

    Prioritising systemic cancer therapies applying ESMO's tools and other resources to assist in improving cancer care globally:the Kazakh experience

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    BACKGROUND: In Kazakhstan, cancer is the second leading cause of death with a major public health and economic burden. In the last decade, cancer care and cancer medicine costs have significantly increased. To improve the efficiency and efficacy of cancer care expenditure and planning, the Kazakhstan Ministry of Health requested assistance from the World Health Organization (WHO) and the European Society for Medical Oncology (ESMO) to review its systemic cancer treatment protocols and essential medicines list and identify high-impact, effective regimens. MATERIALS AND METHODS: ESMO developed a four-phase approach to review Kazakhstan cancer treatment protocols: (i) perform a systematic analysis of the country’s cancer medicines and treatment protocols; (ii) cross-reference the country’s cancer protocols with the WHO Model List of Essential Medicines, the ESMO-Magnitude of Clinical Benefit Scale and the European Medicines Agency’s medicine availability and indications database; (iii) extract treatment recommendations from the ESMO Clinical Practice Guidelines; (iv) expert review for all cancer medicines not on the WHO Model List of Essential Medicines and the country treatment protocols. RESULTS: This ESMO four-phase approach led to the update of the Kazakhstan national essential cancer medicines list and the list of cancer treatment protocols. This review has led to the withdrawal of several low-value or non-evidence-based medicines and a budget increase for cancer care to include all essential and highly effective medicines and treatment options. CONCLUSION: When applied effectively, this four-phase approach can improve access to medicines, efficiency of expenditure and sustainability of cancer systems. The WHO–ESMO collaboration illustrated how, by sharing best practices, tools and resources, we can address access to cancer medicines and positively impact patient care

    Including all voices in international data-sharing governance

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    Background Governments, funding bodies, institutions, and publishers have developed a number of strategies to encourage researchers to facilitate access to datasets. The rationale behind this approach is that this will bring a number of benefits and enable advances in healthcare and medicine by allowing the maximum returns from the investment in research, as well as reducing waste and promoting transparency. As this approach gains momentum, these data-sharing practices have implications for many kinds of research as they become standard practice across the world. Main text The governance frameworks that have been developed to support biomedical research are not well equipped to deal with the complexities of international data sharing. This system is nationally based and is dependent upon expert committees for oversight and compliance, which has often led to piece-meal decisionmaking. This system tends to perpetuate inequalities by obscuring the contributions and the important role of different data providers along the data stream, whether they be low- or middle-income country researchers, patients, research participants, groups, or communities. As research and data-sharing activities are largely publicly funded, there is a strong moral argument for including the people who provide the data in decision-making and to develop governance systems for their continued participation. Conclusions We recommend that governance of science becomes more transparent, representative, and responsive to the voices of many constituencies by conducting public consultations about data-sharing addressing issues of access and use; including all data providers in decision-making about the use and sharing of data along the whole of the data stream; and using digital technologies to encourage accessibility, transparency, and accountability. We anticipate that this approach could enhance the legitimacy of the research process, generate insights that may otherwise be overlooked or ignored, and help to bring valuable perspectives into the decision-making around international data sharing.</p
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