643 research outputs found

    Identifying Sociological Factors for the Success of Space Exploration

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    AbstractAstrosociology factors relevant to success of future space exploration may best be identified through studies of sociological circumstances of past successful explorations, such as the Apollo-Lunar Missions. These studies benefit from access to primary records of the past programs. The Archives and Special Collections Division of the Salmon Library at the University of Alabama Huntsville (UAH) houses large collections of material from the early periods of the space age. The Huntsville campus of the University of Alabama System had its birth in the mid-1950s at the time when the von Braun rocket team was relocated from Texas to Huntsville. The University, the City of Huntsville and the US Government rocket organizations developed in parallel over subsequent years. As a result, the University has a significant space heritage and focus. This is true not only for the engineering and science disciplines, but also for the social sciences. The life of the University spans the period when Huntsville government and industrial organizations were responsible for producing the rocket vehicles to first take mankind to the Moon. That endeavor was surely as significant sociologically as technologically. In the 1980s, Donald E. Tarter, conducted a series of video interviews with some leading members of the original von Braun team. Although the interviews ranged over many engineering subjects, they also recorded personal features of people involved in the Apollo lunar exploration program and the interactions between these people. Such knowledge was of course an objective. These interviews are now in the collections of the UAH Library Archives, along with extensive documentation from the same period. Under sponsorship of the Archives and the NASA-Marshall Retiree Association, the interview series was restarted in 2006 to obtain comparable oral-history interviews with more than fifty US born members of the rocket team from the 1960s. Again these video interviews are rich with insights into the people involved in the Apollo lunar exploration program. A common thought in the original and recent interviews is that the 1960s rocket team was a unique assembly of people with leadership and modes of operation that has not been reproduced since. If mankind is again going to the Moon, Mars, an asteroid or elsewhere in the solar system, a similar assembly of people and sociological conditions may well be required

    Readiness for PENicillin allergy testing: Perception of Allergy Label (PEN-PAL) Survey

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    Clinical Implications: Patients reporting penicillin allergy believe their allergy to be permanent, would take penicillins if tested negative, but are rarely referred for penicillin testing, leading to differential antibiotic utilization

    A single administration of combination therapy inhibits breast tumour progression in bone and modifies both osteoblasts and osteoclasts

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    We have previously shown that repeated sequential administration of doxorubicin, followed 24 h later by zoledronic acid, inhibits tumour growth in models of established breast cancer bone metastasis. As breast cancer patients only receive zoledronic acid every 3-4 weeks, the aim of the current study was to establish the anti-tumour and bone effects of a single administration of doxorubicin/zoledronic acid combination therapy in a bone metastasis model. MDA-MB-231-GFP cells were injected i.c. in 6-week-old nude mice. On day 2, animals received PBS, doxorubicin (2 mg/kg i.v.), zoledronic acid (100 Όg/kg s.c.) or doxorubicin followed 24 h later by zoledronic acid. Anti-tumour effects were assessed on days 15/23 by quantification of apoptotic and proliferating cells and changes in expression of genes implicated in apoptosis, proliferation and bone turnover. Bone effects were assessed by ΌCT analysis, bone histomorphometry and measurement of serum markers. A tumour-free control group was included. Combination treatment reduced bone tumour burden compared to single agent or PBS control and increased levels of tumour cell apoptosis on day 15, but this was no longer detectable on day 23. Animals receiving zoledronic acid had increased bone density, without evidence of tumour-induced lesions. Bone histomorphometry showed that zoledronic acid caused a decrease in osteoblast and osteoclast numbers and an increase in osteoclast size, in both tumour-free and tumour-bearing animals. Our data show that although zoledronic acid modifies the bone microenvironment through effects on both osteoblasts and osteoclasts, this does not result in a significant anti-tumour effect in the absence of doxorubicin. © 2012 Elsevier GmbH. All rights reserved

    Thermodynamics of non-local materials: extra fluxes and internal powers

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    The most usual formulation of the Laws of Thermodynamics turns out to be suitable for local or simple materials, while for non-local systems there are two different ways: either modify this usual formulation by introducing suitable extra fluxes or express the Laws of Thermodynamics in terms of internal powers directly, as we propose in this paper. The first choice is subject to the criticism that the vector fluxes must be introduced a posteriori in order to obtain the compatibility with the Laws of Thermodynamics. On the contrary, the formulation in terms of internal powers is more general, because it is a priori defined on the basis of the constitutive equations. Besides it allows to highlight, without ambiguity, the contribution of the internal powers in the variation of the thermodynamic potentials. Finally, in this paper, we consider some examples of non-local materials and derive the proper expressions of their internal powers from the power balance laws.Comment: 16 pages, in press on Continuum Mechanics and Thermodynamic

    Super black hole as spinning particle: Supersymmetric baglike core

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    We consider particlelike solutions to supergravity based on the Kerr-Newman black hole (BH) solution. The BH singularity is regularized by means of a phase transition to a new vacuum state near the core region confining a dual gauge field. Supersymmetric BPS-saturated domain wall model is suggested which can provide this phase transition and formation the stable charged superconducting core. For spinning particle the core takes the form of thin, relativistically rotaiting disk.Comment: 9 pages, Latex, plenary talks given at the School-Workshop Praha-Spin-2001 (Prague,July 15-28,2001) and at the XXIV International Workshop on Fundamental Problems of HEP and Field Theory (IHEP, June 2001, Protvino

    Instantons and radial excitations in attractive Bose-Einstein condensates

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    Imaginary- and real-time versions of an equation for the condensate density are presented which describe dynamics and decay of any spherical Bose-Einstein condensate (BEC) within the mean field appraoch. We obtain quantized energies of collective finite amplitude radial oscillations and exact numerical instanton solutions which describe quantum tunneling from both the metastable and radially excited states of the BEC of 7Li atoms. The mass parameter for the radial motion is found different from the gaussian value assumed hitherto, but the effect of this difference on decay exponents is small. The collective breathing states form slightly compressed harmonic spectrum, n=4 state lying lower than the second Bogolyubov (small amplitude) mode. The decay of these states, if excited, may simulate a shorter than true lifetime of the metastable state. By scaling arguments, results extend to other attractive BEC-s.Comment: 6 pages, 3 figure

    Optimal low-thrust trajectories to asteroids through an algorithm based on differential dynamic programming

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    In this paper an optimisation algorithm based on Differential Dynamic Programming is applied to the design of rendezvous and fly-by trajectories to near Earth objects. Differential dynamic programming is a successive approximation technique that computes a feedback control law in correspondence of a fixed number of decision times. In this way the high dimensional problem characteristic of low-thrust optimisation is reduced into a series of small dimensional problems. The proposed method exploits the stage-wise approach to incorporate an adaptive refinement of the discretisation mesh within the optimisation process. A particular interpolation technique was used to preserve the feedback nature of the control law, thus improving robustness against some approximation errors introduced during the adaptation process. The algorithm implements global variations of the control law, which ensure a further increase in robustness. The results presented show how the proposed approach is capable of fully exploiting the multi-body dynamics of the problem; in fact, in one of the study cases, a fly-by of the Earth is scheduled, which was not included in the first guess solution

    Bosonization in Higher Dimensions

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    Using the recently discovered connection between bosonization and duality transformations (hep-th/9401105 and hep-th/9403173), we give an explicit path-integral representation for the bosonization of a massive fermion coupled to a U(1) gauge potential (such as electromagnetism) in d space (D=d+1 spacetime) dimensions. The bosonic theory is described by a rank d-1 antisymmetric Kalb-Ramond-type gauge potential. We construct the bosonized lagrangian explicitly in the limit of large fermion mass. We find that the resulting action is local for d=2 (and given by a Chern-Simons action), but nonlocal for d larger than 3. By coupling to a statistical Chern-Simons field for d=2, we obtain a bosonized formulation of anyons. The bosonic theory may be further dualized to a theory involving purely scalars, for any d, and we show this to be governed by a higher-derivative lagrangian for which the scalar decouples from the U(1) gauge potential.Comment: (We had omitted some references and had misspelled `aficionados') plain TeX, 11 pages, McGill-94/33, NEIP-94-006, OSLO-TP 10-9

    Dynamically Induced Spontaneous Symmetry Breaking in 3-3-1 Models

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    We show that in SU(3)_C X SU(3)_L X U(1)_N (3-3-1) models embedded with a singlet scalar playing the role of the axion, after imposing scale invariance, dynamical symmetry breaking of Peccei-Quinn symmetry occurs through the one-loop effective potential for the singlet field. We, then, analyze the structure of spontaneous symmetry breaking by studying the new scalar potential for the model, and verify that electroweak symmetry breaking is tightly connected to the 3-3-1 breaking by the strong constraints among their vacuum expectation values. This offers a valuable guide to write down the correct pattern of symmetry breaking for multi-scalar theories. We also obtained that the accompanying massive pseudo-scalar, instead of acquiring mass of order of Peccei-Quinn scale as we would expect, develops a mass at a much lower scale, a consequence solely of the dynamical breaking.Comment: 12 pages, typos corrected, improved text, conclusions unchange
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