2,635 research outputs found

    Design and Characterization of a Neutron Calibration Facility for the Study of sub-keV Nuclear Recoils

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    As part of an experimental effort to demonstrate sensitivity in a large-mass detector to the ultra-low energy recoils expected from coherent neutrino-nucleus elastic scattering, we have designed and built a highly monochromatic 24 keV neutron beam at the Kansas State University Triga Mark-II reactor. The beam characteristics were chosen so as to mimic the soft recoil energies expected from reactor antineutrinos in a variety of targets, allowing to understand the response of dedicated detector technologies in this yet unexplored sub-keV recoil range. A full characterization of the beam properties (intensity, monochromaticity, contaminations, beam profile) is presented, together with first tests of the calibration setup using proton recoils in organic scintillator.Comment: submitted to Nucl. Instr. Meth.

    Measuring the Spin of the Higgs Boson

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    By studying the threshold dependence of the excitation curve and the angular distribution in Higgs-strahlung at e+e- colliders, e+e- -> HZ, the spin of the Higgs boson in the Standard Model and related extensions can be determined unambiguously in a model-independent way.Comment: 10 pages, 1 Postscript figure, sign typo correcte

    Book Reviews

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    Reviews of the following books: Second Nature: An Environmental History of New England by Richard W. Judd; Hope and Fear in Margaret Chase Smith\u27s America: A Continuous Tangle by Gregory P. Gallant; The 2nd Maine Cavalry in the Civil War: A History and Roster by Ned Smith; Distilled in Maine: A History of Libations, Temperance and Craft Spirits by Kate McCarty; Bangor in World War II: From the Homefront to the Embattled Skies by David H. Bergquist; The Night the Sky Turned Red: The Story of the Great Portland Maine Fire of July 4th 1866, as told by Those Who Lived Through It by Allan M. Levinsk

    The Neutralino Sector of the Next-to-Minimal Supersymmetric Standard Model

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    The Next-to-Minimal Supersymmetric Standard Model (NMSSM) includes a Higgs iso-singlet superfield in addition to the two Higgs doublet superfields of the minimal extension. If the Higgs fields remain weakly coupled up to the GUT scale, as naturally motivated by the concept of supersymmetry, the mixing between singlet and doublet fields is small and can be treated perturbatively. The mass spectrum and mixing matrix of the neutralino sector can be analyzed analytically and the structure of this 5-state system is under good theoretical control. We also determine decay modes and production channels in sfermion cascade decays to these particles at the LHC and pair production in e+e- colliders.Comment: 27 pages, 8 figure

    Phase separation in coupled chaotic maps on fractal networks

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    The phase ordering dynamics of coupled chaotic maps on fractal networks are investigated. The statistical properties of the systems are characterized by means of the persistence probability of equivalent spin variables that define the phases. The persistence saturates and phase domains freeze for all values of the coupling parameter as a consequence of the fractal structure of the networks, in contrast to the phase transition behavior previously observed in regular Euclidean lattices. Several discontinuities and other features found in the saturation persistence curve as a function of the coupling are explained in terms of changes of stability of local phase configurations on the fractals.Comment: (4 pages, 4 Figs, Submitted to PRE

    Public rules about using and owning real estate in Cuba

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    The discussion on urban land continues to be absent in most of the specialized Cuban literature about planning and economic policies, despite its relevance. In very thorough essays about the present challenges and future development of the Cuban economy, nothing is said about the need for adequate public land policies and the implementation of public value capture mechanisms as part of the economic development of the country. The issue is complex, there is a void of almost half a century of not dealing with land value, but these reasons are not sufficient to justify the continued lack of vision in this direction, all the more when the Cuban cities are in desperate need to reverse the deterioration and stagnation that affects them. The Cuban state determines the general rules under which citizens and organisations may own and use real estate. These are rules about property rights and about the limitations - in compliance with aspects such as state security, environmental and heritage protection, economic development, social equity and human and civil rights – on exercising those rights. In doing this, the Cuban state is no different from other states: most states make such rules and enforce them when necessary. What is particular to Cuba is the content of those rules. In particular, the Cuban state has the monopoly to perform land development and management. There are public institutions to plan and deal with all of these aspects, and there are no recognised real estate markets in the country. Another important aspect is the utmost importance given to planning. But in spite of this, Cuban urban planners have rarely been certain of what will be built and where. The main reason for this may be that, despite the numerous master plans to study and anticipate development trends, most of the decisions ultimately involve top officials who envision the projects and establish the investment priorities according to the public interests or needs and the historical moment, irrespective of the plans. This article intends to give a clear picture of how things are done in the public sector, how the administration works, and under which legal framework. I will look at the physical planning system and its importance in the location and implementation of land use, investment projects and housing programs, and at the legal procedures that include licenses for construction, demolition, habitat and other licenses for heritage conservation and redevelopment. I will analyze the difficulties faced by the Cuban planning and legal system with respect to land and urban development, in the attempt to understand the limits imposed by the government on land and urban development, and I will explore to what extent those limits are to blame for the increasing irregularities and violations at all levels of the formal procedures for land and property. I will also introduce the public and personal rights concerning housing, buying and selling, permutes, donations and other tenure alternatives; and clarify the civil responsibilities, namely types of ownership, properties, property registers and so forth in order to expose the opportunities and accessibility of the system but also its limitations

    Coronal mass ejections as expanding force-free structures

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    We mode Solar coronal mass ejections (CMEs) as expanding force-fee magnetic structures and find the self-similar dynamics of configurations with spatially constant \alpha, where {\bf J} =\alpha {\bf B}, in spherical and cylindrical geometries, expanding spheromaks and expanding Lundquist fields correspondingly. The field structures remain force-free, under the conventional non-relativistic assumption that the dynamical effects of the inductive electric fields can be neglected. While keeping the internal magnetic field structure of the stationary solutions, expansion leads to complicated internal velocities and rotation, induced by inductive electric field. The structures depends only on overall radius R(t) and rate of expansion \dot{R}(t) measured at a given moment, and thus are applicable to arbitrary expansion laws. In case of cylindrical Lundquist fields, the flux conservation requires that both axial and radial expansion proceed with equal rates. In accordance with observations, the model predicts that the maximum magnetic field is reached before the spacecraft reaches the geometric center of a CME.Comment: 19 pages, 9 Figures, accepted by Solar Physic

    Sfermion Precision Measurements at a Linear Collider

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    At future e+- e- linear colliders, the event rates and clean signals of scalar fermion production - in particular for the scalar leptons - allow very precise measurements of their masses and couplings and the determination of their quantum numbers. Various methods are proposed for extracting these parameters from the data at the sfermion thresholds and in the continuum. At the same time, NLO radiative corrections and non-zero width effects have been calculated in order to match the experimental accuracy. The substantial mixing expected for the third generation sfermions opens up additional opportunities. Techniques are presented for determining potential CP-violating phases and for extracting tan(beta) from the stau sector, in particular at high values. The consequences of possible large mass differences in the stop and sbottom system are explored in dedicated analyses.Comment: Expanded version of contributions to the proceedings of ICHEP'02 (Amsterdam) and LCWS 2002 (Jeju Island

    Effect of Megasphaera elsdenii NCIMB 41125 dosing on rumen development, volatile fatty acid production and blood β-hydroxybutyrate in neonatal dairy calves

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    Thirty calves were randomly assigned to 2 treatments and fed until weaning (42 days (d) of age). Treatments were a control group (n=15), which did not receive Megasphaera elsdenii (Me0) and a M. elsdenii group, which received a 50-mL oral dose of M. elsdenii NCIMB 41125 (108 CFU/mL) at d 14 d of age (Me14). Calves were given colostrum for the first 3 d followed by limited whole milk feeding. A commercial calf starter was offered ad libitum starting at d 4 until the end of the study. Fresh water was available throughout the study. Feed intake and growth were measured. Blood samples were collected via jugular venipuncture to determine β- hydroxybutyrate (BHBA) concentrations. Fourteen male calves (7 per group) were euthanized on d 42 and digestive tracts harvested. Reticulo-rumen weight was determined and rumen tissue samples collected from the cranial and caudal sacs of the ventral and dorsal portions of the rumen for measurements of papillae length, papillae width, and rumen wall thickness. Dosing with M. elsdenii NCIMB 41125 improved starter dry matter intake (DMI), weaning body weight (BW), and tended to improve average daily gain. Calves in Me14 group had greater plasma BHBA concentration than Me0-calves during the last 3 weeks of the trial, and had at d 42 greater reticulo-rumen weight, papillae width and papillae density compared to Me0. No differences in rumen wall thickness or papillae length were observed between the two groups. Total volatile fatty acids, acetate, and propionate production did not differ between treatments, but butyrate production was greater in Me14 than Me0. Dosing M. elsdenii NCIMB 41125 showed benefit for calves with improved feed intake and rumen development suggesting increased epithelium metabolism and improved absorption of digestive end products.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-03962016-10-31hb201

    An analysis of the sensitivity and specificity of MHC-I and MHC-II immunohistochemical staining in muscle biopsies for the diagnosis of inflammatory myopathies

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    Although there have been several previous reports of immunohistochemical staining for MHC antigens in muscle biopsies, there appears to be a lack of consensus about its routine use in the diagnostic evaluation of biopsies from patients with suspected inflammatory myopathy. Positive MHC-I staining is nonspecific but is widely used as a marker for inflammatory myopathy, whilst the role of MHC-II staining is not clearly defined. We investigated the sensitivity and specificity of MHC-I and MHC-II immunostaining for the diagnosis of inflammatory myopathy in a large group of biopsies from a single reference laboratory. Positive staining for MHC-I was found to have a high sensitivity in biopsies from patients with inflammatory myopathy but a very low specificity, as it was also common in other non-inflammatory myopathies and neurogenic disorders. On the other hand, MHC-II positivity had a much higher specificity in all major subgroups of inflammatory myopathy, especially inclusion body myositis. The findings indicate that the combination of MHC-I and MHC-II staining results in a higher degree of specificity for the diagnosis of inflammatory myopathy and that in biopsies with inflammation, positive MHC-II staining strongly supports the diagnosis of an immune-mediated myopathy. We recommend that immunohistochemical staining for both MHC-I and MHC-II should be included routinely in the diagnostic evaluation of muscle biopsies from patients with suspected inflammatory myopathy. However, as the sensitivity and interpretation of MHC staining may depend on the technique used, further studies are needed to compare procedures in different centres and develop standardised protocols
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