2,163 research outputs found

    Human performance control monitoring systems Interim report no. 2

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    Computer program to simulate second order servo system dynamics under automatic and manual contro

    The Effective Potential And Additional Large Radius Compactified Space-Time Dimensions

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    The consequences of large radius extra space-time compactified dimensions on the four dimensional one loop effective potential are investigated for a model which includes scalar self interactions and Yukawa coupling to fermions. The Kaluza-Klein tower of states associated with the extra compact dimensions shifts the location of the effective potential minimum and modifies its curvature. The dependence of these effects on the radius of the extra dimension is illustrated for various choices of coupling constants and masses. For large radii, the consequence of twisting the fermion boundary condition on the compactified dimensions is numerically found to produce but a negligible effect on the effective potential.Comment: 14 pages, LaTeX, 6 Postscript figure

    Human performance control monitoring system Final report, Jan. 1965 - Feb. 1966

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    Computer program simulation of servomechanism controlled by adaptive logic element trained by monitoring of human performance - mathematical mode

    Electric dipole moments of charged leptons in the split fermion scenario in the two Higgs doublet model

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    We predict the charged lepton electric dipole moments in the split fermion scenario in the framework of the two Higgs doublet model. We observe that the numerical value of the muon (tau) electric dipole moment is at the order of the magnitude of 1022(ecm)10^{-22} (e-cm) (1020(ecm)10^{-20} (e-cm)) and there is an enhancement in the case of two extra dimensions, especially for the tau lepton electric dipole moment.Comment: 17 pages, 5 figure

    Collider Tests of Compact Space Dimensions Using Weak Gauge Bosons

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    We present collider tests of the recent proposal for weak-scale quantum gravity due to new large compact space dimensions in which only the graviton (\G) propagates. We show that the existing high precision LEP-I ZZ-pole data can impose non-trivial constraints on the scale of the new dimensions, via the decay mode Z\to f\bar{f}+\G (f=q,f=q,\ell). These bounds are comparable to those obtained at high energy colliders and provide the first sensitive probe of the scalar graviton. We also study W(Z)+\G production and the anomalous WW(ZZ)WW(ZZ) signal from virtual \G-states at the Fermilab Tevatron, and compare them with the LEP-I bound and those from LEP-II and future linear colliders.Comment: 4 pages, 1 postscript figure include

    Occupation and three-year incidence of respiratory symptoms and lung function decline: the ARIC Study

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    <p>Abstract</p> <p>Background</p> <p>Specific occupations are associated with adverse respiratory health. Inhalation exposures encountered in these jobs may place workers at risk of new-onset respiratory disease.</p> <p>Methods</p> <p>We analyzed data from 8,967 participants from the Atherosclerosis Risk in Communities (ARIC) study, a longitudinal cohort study. Participants included in this analysis were free of chronic cough and phlegm, wheezing, asthma, chronic bronchitis, emphysema, and other chronic lung conditions at the baseline examination, when they were aged 45-64 years. Using data collected in the baseline and first follow-up examination, we evaluated associations between occupation and the three-year incidence of cough, phlegm, wheezing, and airway obstruction and changes in forced expiratory volume in one second (FEV<sub>1</sub>) and forced vital capacity (FVC) measured by spirometry. All associations were adjusted for age, cigarettes per day, race, smoking status, and study center.</p> <p>Results</p> <p>During the approximately three-year follow-up, the percentage of participants developing chronic cough was 3%; chronic phlegm, 3%; wheezing, 3%; and airway obstruction, defined as FEV<sub>1 </sub>< lower limit of normal (LLN) and FEV<sub>1</sub>/FVC < LLN, 2%. The average annual declines in FEV<sub>1 </sub>and FVC were 56 mL and 66 mL, respectively, among men and 40 mL and 52 mL, respectively, among women. Relative to a referent category of managerial and administrative support occupations, elevated risks of new-onset chronic cough and chronic phlegm were observed for mechanics and repairers (chronic cough: RR: 1.81, 95% CI: 1.02, 3.21; chronic phlegm: RR: 2.10, 95% CI: 1.23, 3.57) and cleaning and building service workers (chronic cough: RR: 1.85, 95% CI: 1.01, 3.37; chronic phlegm: RR: 2.28, 95% CI: 1.27, 4.08). Despite the elevated risk of new-onset symptoms, employment in cleaning and building services was associated with attenuated lung function decline, particularly among men, who averaged annual declines in FEV<sub>1 </sub>and FVC of 14 mL and 23 mL, respectively, less than the declines observed in the referent population.</p> <p>Conclusions</p> <p>Employment in mechanic and repair jobs and cleaning and building service occupations are associated with increased incidence of respiratory symptoms. Specific occupations affect the respiratory health of adults without pre-existing respiratory health symptoms and conditions, though long-term health consequences of inhalation exposures in these jobs remain largely unexplored.</p

    Indirect Collider Signals for Extra Dimensions

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    A recent suggestion that quantum gravity may become strong near the weak scale has several testable consequences. In addition to probing for the new large (submillimeter) extra dimensions associated with these theories via gravitational experiments, one could search for the Kaluza Klein towers of massive gravitons which are predicted in these models and which can interact with the fields of the Standard Model. Here we examine the indirect effects of these massive gravitons being exchanged in fermion pair production in \epem annihilation and Drell-Yan production at hadron colliders. In the latter case, we examine a novel feature of this theory, which is the contribution of gluon gluon initiated processes to lepton pair production. We find that these processes provide strong bounds, up to several TeV, on the string scale which are essentially independent of the number of extra dimensions. In addition, we analyze the angular distributions for fermion pair production with spin-2 graviton exchanges and demonstrate that they provide a smoking gun signal for low-scale quantum gravity which cannot be mimicked by other new physics scenarios.Comment: Corrected typos, added table and reference

    Characterisation of the secondary-neutron production in particle therapy treatments with the MONDO tracking detector

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    Particle Therapy (PT) is a non-invasive technique that exploits charged light ions for the irradiation of tumours that cannot be effectively treated with surgery or conventional radiotherapy. While the largest dose fraction is released to the tumour volume by the primary beam, a non-negligible amount of additional dose is due to the beam fragmentation that occurs along the path towards the target volume. In particular, the produced neutrons are particularly dangerous as they can release their energy far away from the treated area, increasing the risk of developing a radiogenic secondary malignant neoplasm after undergoing a treatment. A precise measurement of the neutron flux, energy spectrum and angular distributions is eagerly needed in order to improve the treatment planning system software, so as to predict the normal tissue toxicity in the target region and the risk of late complications in the whole body. The MONDO (MOnitor for Neutron Dose in hadrOntherapy) project is dedicated to the characterisation of the secondary ultra-fast neutrons ([20-400] MeV energy range) produced in PT. The neutron tracking system exploits the reconstruction of the recoil protons produced in two consecutive (n, p) elastic scattering interactions to measure simultaneously the neutron incoming direction and energy. The tracker active media is a matrix of thin squared scintillating fibers arranged in orthogonally oriented layers that are read out by a sensor (SBAM) based on SPAD (Single-Photon Avalanche Diode) detectors developed in collaboration with the Fondazione Bruno Kessler (FBK)
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