605 research outputs found

    New experimental data for the decays ϕμ+μ\phi\to\mu^+\mu^- and ϕπ+π\phi\to\pi^+\pi^- from SND detector

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    The processes e+eμ+μe^+e^-\to\mu^+\mu^- and e+eπ+πe^+e^-\to\pi^+\pi^- have been studied with SND detector at VEPP-2M e+ee^+e^- collider in the vicinity of ϕ(1020)\phi(1020) resonance. The branching ratios B(ϕμ+μ)=(3.30±0.45±0.32)×104B(\phi\to\mu^+\mu^-)=(3.30\pm 0.45\pm 0.32)\times 10^{-4} and B(ϕπ+π)=(0.71±0.11±0.09)×104B(\phi\to\pi^+\pi^-)=(0.71\pm 0.11\pm 0.09)\times 10^{-4} were obtained.Comment: 5 pages, 4 figures, talk given at 8th International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199

    Influence of air Gap Between the Transformer of Resistance and Object of Monitoring on Temperature Measurement Error

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    In operation the description of the developed heattransfer model in thermotransformers of resistance (RTD) in the conditions of air gap between surfaces of the sensor and object of measurement is provided. Research of influence of thickness of air gap on the relative error of temperature measurement by platinum, copper and nickel thermotransformers of resistance in the ranges of temperatures corresponding to each type is executed. Dependences of minimum necessary duration of heating up of sensors on the taken temperatures are received

    Burden of lymphedema in long-term breast cancer survivors by race and age

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    Background: Risk assessment for breast cancer–related lymphedema has emphasized upper-limb symptoms and treatment-related risk factors. This article examined breast cancer–related lymphedema after surgery, overall and in association with broader demographic and clinical features. Methods: The Carolina Breast Cancer Study phase 3 followed participants for breast cancer–related lymphedema from baseline (on average, 5 months after breast cancer diagnosis) to 7 years after diagnosis. Among 2645 participants, 552 self-reported lymphedema cases were identified. Time-to-lymphedema curves and inverse probability weighted conditional Cox proportional hazards model were used to evaluate whether demographics and clinical features were associated with breast cancer–related lymphedema. Results: Point prevalence of breast cancer–related lymphedema was 6.8% at baseline, and 19.9% and 23.8% at 2 and 7 years after diagnosis, respectively. Most cases had lymphedema in the arm (88%-93%), whereas 14% to 27% presented in the trunk and/or breast. Beginning approximately 10 months after diagnosis, younger Black women had the highest risk of breast cancer–related lymphedema and older non-Black women had the lowest risk. Positive lymph node status, larger tumor size (>5 cm), and estrogen receptor–negative breast cancer, as well as established risk factors such as higher body mass index, removal of more than five lymph nodes, mastectomy, chemotherapy, and radiation therapy, were significantly associated with increased hazard (1.5- to 3.5-fold) of lymphedema. Conclusions: Findings highlight that hazard of breast cancer–related lymphedema differs by demographic characteristics and clinical features. These factors could be used to identify those at greatest need of lymphedema prevention and early intervention. Lay summary: In this study, the aim was to investigate breast cancer–related lymphedema (BCRL) burden. This study found that risk of BCRL differs by race, age, and other characteristics

    Theoretical study of lepton events in the atmospheric neutrino experiments at SuperK

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    Super-Kamiokande has reported the results for the lepton events in the atmospheric neutrino experiment. These results have been presented for a 22.5kT water fiducial mass on an exposure of 1489 days, and the events are divided into sub-GeV, multi-GeV and PC events. We present a study of nuclear medium effects in the sub-GeV energy region of atmospheric neutrino events for the quasielastic scattering, incoherent and coherent pion production processes, as they give the most dominant contribution to the lepton events in this energy region. We have used the atmospheric neutrino flux given by Honda et al. These calculations have been done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reactions. The inelastic reactions leading to production of leptons along with pions is calculated in a Δ\Delta - dominance model by taking into account the renormalization of Δ\Delta properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We present the results for the lepton events obtained in our model with and without nuclear medium effects, and compare them with the Monte Carlo predictions used in the simulation and the experimentally observed events reported by the Super-Kamiokande collaboration.Comment: 23 pages, 13 figure

    Measurement of the Strong Coupling alpha s from Four-Jet Observables in e+e- Annihilation

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    Data from e+e- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham algorithm resolution parameter ycut. The four-jet rate is compared to next-to-leading order calculations that include the resummation of large logarithms. The strong coupling measured from the four-jet rate is alphas(Mz0)= 0.1182+-0.0003(stat.)+-0.0015(exp.)+-0.0011(had.)+-0.0012(scale)+-0.0013(mass) in agreement with the world average. Next-to-leading order fits to the D-parameter and thrust minor event-shape observables are also performed for the first time. We find consistent results, but with significantly larger theoretical uncertainties.Comment: 25 pages, 15 figures, Submitted to Euro. Phys. J.

    D* Production in Deep Inelastic Scattering at HERA

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    This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D+(D0Kπ+)π+D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ (+ c.c.) has been used in the study. The e+pe^+p cross section for inclusive D^{*\pm} production with 5<Q2<100GeV25<Q^2<100 GeV^2 and y<0.7y<0.7 is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {1.3<pT(D±)<9.01.3<p_T(D^{*\pm})<9.0 GeV and η(D±)<1.5| \eta(D^{*\pm}) |<1.5}. Differential cross sections as functions of p_T(D^{*\pm}), η(D±),W\eta(D^{*\pm}), W and Q2Q^2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and η\eta(D^{*\pm}), the charm contribution F2ccˉ(x,Q2)F_2^{c\bar{c}}(x,Q^2) to the proton structure function is determined for Bjorken xx between 2 \cdot 104^{-4} and 5 \cdot 103^{-3}.Comment: 17 pages including 4 figure

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

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    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    ‘Citizen scientists’ on citizen science

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    Citizen science, also known as participatory or community science, involves the participation of non-professionally trained individuals in scientific research. This article, part of a series of articles aiming to map and theorise the postdigital dimensions of citizen science, presents diverse narratives from individuals actively engaged in citizen science endeavors. The authors were invited to share their experiences, motivations, challenges, and opportunities in their own words. Their perspectives are organized into three categories: (1) citizen science as a mediator between professional and amateur science, (2) citizen science for diverse publics and community action, and (3) citizen science from the margins. These narratives illuminate citizen science as not just a theoretical construct, but a dynamic methodological prism, revealing the complex entanglement of the postdigital realm and citizen science through innovative sociotechnical methods and approaches. Each contribution highlights the rich possibilities and challenges arising from the intertwining of community researchers and technology in the pursuit of knowledge, meaning, and action. This tapestry of experiences invites further exploration of the evolving landscape of postdigital citizen science

    Theoretical and technological building blocks for an innovation accelerator

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    The scientific system that we use today was devised centuries ago and is inadequate for our current ICT-based society: the peer review system encourages conservatism, journal publications are monolithic and slow, data is often not available to other scientists, and the independent validation of results is limited. Building on the Innovation Accelerator paper by Helbing and Balietti (2011) this paper takes the initial global vision and reviews the theoretical and technological building blocks that can be used for implementing an innovation (in first place: science) accelerator platform driven by re-imagining the science system. The envisioned platform would rest on four pillars: (i) Redesign the incentive scheme to reduce behavior such as conservatism, herding and hyping; (ii) Advance scientific publications by breaking up the monolithic paper unit and introducing other building blocks such as data, tools, experiment workflows, resources; (iii) Use machine readable semantics for publications, debate structures, provenance etc. in order to include the computer as a partner in the scientific process, and (iv) Build an online platform for collaboration, including a network of trust and reputation among the different types of stakeholders in the scientific system: scientists, educators, funding agencies, policy makers, students and industrial innovators among others. Any such improvements to the scientific system must support the entire scientific process (unlike current tools that chop up the scientific process into disconnected pieces), must facilitate and encourage collaboration and interdisciplinarity (again unlike current tools), must facilitate the inclusion of intelligent computing in the scientific process, must facilitate not only the core scientific process, but also accommodate other stakeholders such science policy makers, industrial innovators, and the general public
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