774 research outputs found

    Amplitude and phase representation of quantum invariants for the time dependent harmonic oscillator

    Full text link
    The correspondence between classical and quantum invariants is established. The Ermakov Lewis quantum invariant of the time dependent harmonic oscillator is translated from the coordinate and momentum operators into amplitude and phase operators. In doing so, Turski's phase operator as well as Susskind-Glogower operators are generalized to the time dependent harmonic oscillator case. A quantum derivation of the Manley-Rowe relations is shown as an example

    SatNEx: A Network of Excellence Providing Training in Satellite Communications

    Get PDF
    YesSatellite communications represents a specialised area of telecommunications. While the development of satellite technology is relatively slow in comparison to wireless networks evolution, due to the need for high reliability, the services that satellites are able to offer are evolving at much the same pace as their terrestrial counterparts. It is within this context that the satellite communications network of excellence (SatNEx) has evolved its initiative, the aim being to serve the engineering community with the latest technological trends, while also providing a solid grounding in the fundamentals for those new to the subject area.European Commission Framework Programme

    Movement of pathogens between horticultural crops and endemic trees in the Kimberleys

    Get PDF
    Recently a survey of endophytes associated with boabs (Adansonia gregorrii) and associated tree species in the Kimberleys, Western Australia has resulted in the description of seven new species in the Botryosphaeriaceae (Pavlic et al. 2008). Additionally several common species of Lasiodiplodia, (L. theobromae, L. pseudoptheobromae and L. parva) were also isolated as endophytes of endemic tree species. Concurrently, surveys in the Ord River Irrigation Area (ORIA) have revealed Mangiferum indica trees showing symptoms of dieback and cankers. In this project we isolated, identified and determined the pathogenicity of fungi associated with these cankers

    Processing of ultrafine-size particulate metal matrix composites by advanced shear technology

    Get PDF
    Copyright @ 2009 ASM International. This paper was published in Metallurgical & Materials Transactions A 40A(3) and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Lack of efficient mixing technology to achieve a uniform distribution of fine-size reinforcement within the matrix and the high cost of producing components have hindered the widespread adaptation of particulate metal matrix composites (PMMCs) for engineering applications. A new rheo-processing method, the melt-conditioning high-pressure die-cast (MC-HPDC) process, has been developed for manufacturing near-net-shape components of high integrity. The MC-HPDC process adapts the well-established high shear dispersive mixing action of a twin-screw mechanism to the task of overcoming the cohesive force of the agglomerates under a high shear rate and high intensity of turbulence. This is followed by direct shaping of the slurry into near-net-shape components using an existing cold-chamber die-casting process. The results indicate that the MC-HPDC samples have a uniform distribution of ultrafine-sized SiC particles throughout the entire sample in the as-cast condition. Compared to those produced by conventional high-pressure die casting (HPDC), MC-HPDC samples have a much improved tensile strength and ductility.EP-SR

    Effective interaction between helical bio-molecules

    Get PDF
    The effective interaction between two parallel strands of helical bio-molecules, such as deoxyribose nucleic acids (DNA), is calculated using computer simulations of the "primitive" model of electrolytes. In particular we study a simple model for B-DNA incorporating explicitly its charge pattern as a double-helix structure. The effective force and the effective torque exerted onto the molecules depend on the central distance and on the relative orientation. The contributions of nonlinear screening by monovalent counterions to these forces and torques are analyzed and calculated for different salt concentrations. As a result, we find that the sign of the force depends sensitively on the relative orientation. For intermolecular distances smaller than 6A˚6\AA it can be both attractive and repulsive. Furthermore we report a nonmonotonic behaviour of the effective force for increasing salt concentration. Both features cannot be described within linear screening theories. For large distances, on the other hand, the results agree with linear screening theories provided the charge of the bio-molecules is suitably renormalized.Comment: 18 pages, 18 figures included in text, 100 bibliog

    Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System

    Full text link
    We present a series of measurements based on K -> pi+pi- and K -> pi0pi0 decays collected in 1996-1997 by the KTeV experiment (E832) at Fermilab. We compare these four K -> pipi decay rates to measure the direct CP violation parameter Re(e'/e) = (20.7 +- 2.8) x 10^-4. We also test CPT symmetry by measuring the relative phase between the CP violating and CP conserving decay amplitudes for K->pi+pi- (phi+-) and for K -> pi0pi0 (phi00). We find the difference between the relative phases to be Delta-phi = phi00 - phi+- = (+0.39 +- 0.50) degrees and the deviation of phi+- from the superweak phase to be phi+- - phi_SW =(+0.61 +- 1.19) degrees; both results are consistent with CPT symmetry. In addition, we present new measurements of the KL-KS mass difference and KS lifetime: Delta-m = (5261 +- 15) x 10^6 hbar/s and tauS = (89.65 +- 0.07) x 10^-12 s.Comment: Submitted to Phys. Rev. D, August 6, 2002; 37 pages, 32 figure

    Clinical audit of malaria diagnosis in urban primary curative care clinics, Zimbabwe

    Get PDF
    A CAJM journal article.Clinical audit was performed on the accuracy of malaria diagnosis by nursing staff within Harare City Health Department using diagnosis by doctors as the reference standard. This was found to be about 10 pc based on symptoms. The criteria for diagnosis of malaria as in ZEDAP manuals and in-house training were not being utilised. Pyrexia was not present in 40 pc of the patients. Serious illnesses were occasionally dismissed as malaria and not treated appropriately or reviewed. The most common misdiagnosis was of acute respiratory tract infections which also have clear guidelines for diagnosis. More appropriate training methods need to be developed to improve the diagnostic capacity of nursing staff who are front line providers of primary health care. This study shows the importance of performing an audit for process evaluation, compared to set standards and to be used for improving the quality of services

    Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

    Get PDF
    We present first measurements of the ϕ\phi-meson elliptic flow (v2(pT)v_{2}(p_{T})) and high statistics pTp_{T} distributions for different centralities from sNN\sqrt{s_{NN}} = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2v_{2} of the ϕ\phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Ω\Omega to those of the ϕ\phi as a function of transverse momentum is consistent with a model based on the recombination of thermal ss quarks up to pT4p_{T}\sim 4 GeV/cc, but disagrees at higher momenta. The nuclear modification factor (RCPR_{CP}) of ϕ\phi follows the trend observed in the KS0K^{0}_{S} mesons rather than in Λ\Lambda baryons, supporting baryon-meson scaling. Since ϕ\phi-mesons are made via coalescence of seemingly thermalized ss quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

    Measurement of open charm production in dd+Au collisions at sNN\sqrt{s_{NN}}=200 GeV

    Full text link
    We present the first comprehensive measurement of D0,D+,D+D^{0}, D^{+}, D^{*+} and their charge conjugate states at mid-rapidity in dd+Au collisions at sNN\sqrt{s_{_{NN}}}=200 GeV using the STAR TPC. The directly measured open charm multiplicity distribution covers a broad transverse momentum region of 0<pT<11<p_{T}<11 GeV/cc. The measured dN/dydN/dy at mid-rapidity for D0D^{0} is 0.0265±0.0036(stat.)±0.0071(syst.)0.0265\pm 0.0036 (stat.) \pm 0.0071 (syst.) and the measured D+/D0D^{*+}/D^{0} and D+/D0D^{+}/D^{0} ratios are approximately equal with a magnitude of 0.40±0.09(stat.)±0.13(syst.)0.40\pm 0.09(stat.) \pm 0.13(syst.). The total ccˉc\bar{c} cross section per nucleon-nucleon collision extracted from this study is 1.18±0.21(stat.)±0.39(syst.)1.18 \pm 0.21(stat.) \pm 0.39(syst.) mb. The direct measurement of open charm production is consistent with STAR single electron data. This cross section is higher than expectations from PYTHIA and other pQCD calculations. The measured pTp_{T} distribution is harder than the pQCD prediction using the Peterson fragmentation function.Comment: Quark Matter 2004 Proceeding
    corecore