1,104 research outputs found

    Planning the Future of U.S. Particle Physics (Snowmass 2013): Chapter 6: Accelerator Capabilities

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    These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 6, on Accelerator Capabilities, discusses the future progress of accelerator technology, including issues for high-energy hadron and lepton colliders, high-intensity beams, electron-ion colliders, and necessary R&D for future accelerator technologies.Comment: 26 page

    Euclidean Approach to the Entropy for a Scalar Field in Rindler-like Space-Times

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    The off-shell entropy for a massless scalar field in a D-dimensional Rindler-like space-time is investigated within the conical Euclidean approach in the manifold C_\be\times\M^N, C_\be being the 2-dimensional cone, making use of the zeta-function regularisation. Due to the presence of conical singularities, it is shown that the relation between the zeta-function and the heat kernel is non trivial and, as first pointed out by Cheeger, requires a separation between small and large eigenvalues of the Laplace operator. As a consequence, in the massless case, the (naive) non existence of the Mellin transform is by-passed by the Cheeger's analytical continuation of the zeta-function on manifold with conical singularities. Furthermore, the continuous spectrum leads to the introduction of smeared traces. In general, it is pointed out that the presence of the divergences may depend on the smearing function and they arise in removing the smearing cutoff. With a simple choice of the smearing function, horizon divergences in the thermodynamical quantities are recovered and these are similar to the divergences found by means of off-shell methods like the brick wall model, the optical conformal transformation techniques or the canonical path integral method.Comment: 17 pages, LaTex. A sign error corrected and few comments adde

    Проблемы технического нормирования шумовых характеристик текстильных машин

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    Для целей оценки соответствия шумовых характеристик машин требованиям санитарных норм предложено использовать обобщенные предельно допустимые шумовые характеристики, которые задают предельно допустимые характеристики для близких по типу машин, объединенных в группы с учетом характерной плотности их установки и условий эксплуатации. Для уточненного определения этих характеристик целесообразно использовать методику, учитывающую звукопоглощение и рассеяние шума поверхностью машин, плотность тел рассеяния в поперечном сечении производственного помещения и его акустические и геометрические характеристики.For the purposes of assessing the compliance of noise characteristics of machines with the requirements of sanitary standards, it is suggested to use generalized maximum permissible noise characteristics that set the maximum permissible characteristics for similar machines, grouped together, taking into account the characteristic density of their installation and operating conditions. For an accurate definition of these characteristics, it is advisable to use a technique that takes into account the sound absorption and noise scattering by the machine surface, the density of scattering bodies in the cross section of the production room and its acoustic and geometric characteristics

    A Magnetic Transition Probed by the Ce Ion in Square-Lattice Antiferromagnet CeMnAsO

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    We examined the magnetic properties of the square-lattice antiferromagnets CeMnAsO and LaMnAsO and their solid solutions La1-xCexMnAsO by resistivity, magnetic susceptibility, and heat capacity measurements below room temperature. A first-order phase transition is observed at 34.1 K, below which the ground-state doublet of the Ce ion splits by 3.53 meV. It is likely that Mn moments already ordered above room temperature are reoriented at the transition, as reported for related compounds, such as NdMnAsO and PrMnSbO. This transition generates a large internal magnetic field at the Ce site in spite of the fact that simple Heisenberg interactions should be cancelled out at the Ce site owing to geometrical frustration. The transition takes place at nearly the same temperature with the substitution of La for Ce up to 90%. The Ce moment does not undergo long-range order by itself, but is parasitically induced at the transition, serving as a good probe for detecting the magnetism of Mn spins in a square lattice.Comment: 11 pages, 5 figures, to be published in J. Phys. Soc. Jp

    Boundary relations and generalized resolvents of symmetric operators

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    The Kre\u{\i}n-Naimark formula provides a parametrization of all selfadjoint exit space extensions of a, not necessarily densely defined, symmetric operator, in terms of maximal dissipative (in \dC_+) holomorphic linear relations on the parameter space (the so-called Nevanlinna families). The new notion of a boundary relation makes it possible to interpret these parameter families as Weyl families of boundary relations and to establish a simple coupling method to construct the generalized resolvents from the given parameter family. The general version of the coupling method is introduced and the role of boundary relations and their Weyl families for the Kre\u{\i}n-Naimark formula is investigated and explained.Comment: 47 page

    Evaluation of the propensity of strain burst in brittle granite based on post-peak energy analysis

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    Available online 11 October 2019The increasing demand for resources and depletion of near ground mineral resources caused deeper mining operations under highstress rock mass conditions. As a result of this, strain burst, which is the sudden release of stored strain energy in the surrounding rock mass, has become more prevalent and created a considerable threat to workers and construction equipment. It is, therefore, imperative to understand how strain burst mechanism and stored excess strain energy are affected due to the high confinement in deep underground conditions. For this purpose, post-peak energy distributions for brittle rocks were investigated using a newly developed energy calculation method associated with acoustic emission (AE). A series of quasi-static uniaxial and triaxial compression tests controlled by the circumferential expansion was conducted. Snap-back behaviour known as Class-II behaviour associated with energy evolution and the material response under self-sustaining failure were analysed on granites under a wide range of confining pressures (0–60 MPa). The experimental results underline that the energy evolution characteristics are strongly linked to confinement. Stored elastic strain energy (dUE), energy consumed by dominating cohesion weakening (dUCW) and energy dissipated during mobilisation of frictional failure (dUFM) showed a rising trend as increasing the confining pressure. An intrinsic ejection velocity was proposed to express the propensity of strain burst that was purely determined by the excess strain energy released from Class II rock.Selahattin Akdag, Murat Karakus, Giang D. Nguyen, Abbas Taheri, Thomas Brunin

    Tamoxifen enhances the cytotoxic effects of nelfinavir in breast cancer cells

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    Introduction: The HIV protease inhibitor nelfinavir is currently under investigation as a new anti-cancer drug. Several studies have shown that nelfinavir induces cell cycle arrest, endoplasmic reticulum stress, autophagy, and apoptosis in cancer cells. In the present article, the effect of nelfinavir on human breast cancer cells is examined and potential combination treatments are investigated. Methods: The effects of nelfinavir and tamoxifen on the human breast cancer cell lines MCF7, T47 D, MDA-MB-453, and MDA-MB-435 were tested by analysing their influence on cell viability (via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay), apoptosis (annexin binding, poly(ADP-ribose) polymerase cleavage), autophagy (autophagy marker light chain 3B expression), endoplasmic reticulum stress (binding protein and activating transcription factor 3 expression), and the occurrence of oxidative stress (intracellular glutathione level). Results: Nelfinavir induced apoptosis in all four breast cancer cell lines tested, although the extent of autophagy and endoplasmic reticulum stress varied among the cell lines. The concentration of nelfinavir needed for an efficient induction of apoptosis in breast cancer cells could be reduced from 15 mu g/ml to 6 mu g/ml when combined with tamoxifen. At a concentration of 6 mu g/ml, tamoxifen substantially enhanced the endoplasmic reticulum stress reaction in those cell lines that responded to nelfinavir with binding protein (BiP) upregulation (MCF7, T47D), and enhanced autophagy in cell lines that responded to nelfinavir treatment with autophagy marker light chain 3B upregulation (MDA-MB-453). Although tamoxifen has been described to be able to induce oxidative stress at concentrations similar to those applied in this study (6 mu g/ml), we observed that nelfinavir but not tamoxifen reduced the intracellular glutathione level of breast cancer cells within hours of application by up to 32%, suggesting the induction of oxidative stress was an early event and an additional cause of the apoptosis induced by nelfinavir. Conclusions: The results demonstrate that nelfinavir may be an effective drug against breast cancer and could be combined with tamoxifen to enhance its efficacy against breast cancer cells. Moreover, the cytotoxic effect of a tamoxifen and nelfinavir combination was independent of the oestrogen receptor status of the analysed breast cancer cells, suggesting a potential benefit of a combination of these two drugs even in patients with no hormone-responsive tumours. We therefore recommend that clinical studies on nelfinavir with breast cancer patients should include this drug combination to analyse the therapeutic efficacy as well as the safety and tolerability of this potential treatment option

    Towards a Generalized Distribution Formalism for Gauge Quantum Fields

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    We prove that the distributions defined on the Gelfand-Shilov spaces, and hence more singular than hyperfunctions, retain the angular localizability property. Specifically, they have uniquely determined support cones. This result enables one to develop a distribution-theoretic techniques suitable for the consistent treatment of quantum fields with arbitrarily singular ultraviolet and infrared behavior. The proofs covering the most general case are based on the use of the theory of plurisubharmonic functions and Hormander's estimates.Comment: 12 p., Department of Theoretical Physics, P.N.Lebedev Physical Institute, Leninsky prosp. 53, Moscow 117924, Russi

    Quantum Fields in Hyperbolic Space-Times with Finite Spatial Volume

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    The one-loop effective action for a massive self-interacting scalar field is investigated in 44-dimensional ultrastatic space-time R×H3/Γ R \times H^3/\Gamma, H3/ΓH^3/\Gamma being a non-compact hyperbolic manifold with finite volume. Making use of the Selberg trace formula, the ζ\zeta-function related to the small disturbance operator is constructed. For an arbitrary gravitational coupling, it is found that ζ(s)\zeta(s) has a simple pole at s=0s=0. The one-loop effective action is analysed by means of proper-time regularisations and the one-loop divergences are explicitly found. It is pointed out that, in this special case, also ζ\zeta-function regularisation requires a divergent counterterm, which however is not necessary in the free massless conformal invariant coupling case. Finite temperature effects are studied and the high-temperature expansion is presented. A possible application to the problem of the divergences of the entanglement entropy for a free massless scalar field in a Rindler-like space-time is briefly discussed.Comment: 13 pages, LaTex. The contribution of hyperbolic elements has been added. Other minor corrections and reference
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