14,235 research outputs found

    Upper limit on mh in the MSSM and M-SUGRA vs. prospective reach of LEP

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    The upper limit on the lightest CP-even Higgs boson mass, mh, is analyzed within the MSSM as a function of tan(beta) for fixed mtop and Msusy. The impact of recent diagrammatic two-loop results on this limit is investigated. We compare the MSSM theoretical upper bound on mh with the lower bound obtained from experimental searches at LEP. We estimate that with the LEP data taken until the end of 1999, the region mh < 108.2 GeV can be excluded at the 95% confidence level. This corresponds to an excluded region 0.6 <= tan(beta) <= 1.9 within the MSSM for mtop = 174.3 GeV and Msusy <= 1 TeV. The final exclusion sensitivity after the end of LEP, in the year 2000, is also briefly discussed. Finally, we determine the upper limit on mh within the Minimal Supergravity (M-SUGRA) scenario up to the two-loop level, consistent with radiative electroweak symmetry breaking. We find an upper bound of mh \approx 127 GeV for mtop = 174.3 GeV in this scenario, which is slightly below the bound in the unconstrained MSSM.Comment: 10 pages, 3 figure

    Linear Invariant Systems Theory for Signal Enhancement

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    This paper discusses a linear time invariant (LTI) systems approach to signal enhancement via projective subspace techniques. It provides closed form expressions for the frequency response of data adaptive finite impulse response eigenfilters. An illustrative example using speech enhancement is also presented.Este artigo apresenta a aplicação da teoria de sistemas lineares invariantes no tempo (LTI) na anĂĄlise de tĂ©cnicas de sub-espaço. A resposta em frequĂȘncia dos filtros resultantes da decomposição em valores singulares Ă© obtida aplicando as propriedades dos sistemas LTI

    Extension of Tycho catalog for low-extinction windows in the galactic bulge

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    We present in this work secondary catalogs up to mVal∌13m_{Val} \sim 13 based on the Tycho reference frame (ESA, 1997) for 12 selected low-extinction fields towards the galactic bulge. The observations have been performed with the Askania-Zeiss Meridian Circle equiped with a CCD camera, located at the Abrah\~ao de Moraes Observatory (Valinhos, Brazil) and operated by the Institute of Astronomy and Geophysics, S\~ao Paulo University. The presented catalog, though not complete, has been designed to help in intensive search programmes (e.g. microlensing and variable searches) and therefore the selected standards have a high astrometric and photometric (VV band, approximately) quality. The mean precisions obtained were 0.0018s0.0018^{s} in α\alpha, 0.013'' in ÎŽ\delta, 0.030 for the standard deviation in magnitude and 0.0042 for the magnitude when weighted with the error bars in each night (in the mean, 42 stars for the catalog of each window). Tables B.1 to B.12 are also available in eletronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.Comment: 16 pages, 6 figures, A&A Latex style. Published in A&A

    Stellar variability in low-extinction regions towards the Galactic Bulge

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    Intensive monitoring of low-extinction windows towards the galactic bulge has provided in the last years valuable information for studies about the dynamics, kinematics and formation history of this part of the galaxy, mainly by characterizing the bulge stellar populations (Paczy\'nski, 1996). Since 1997, we have been conducting an intensive photometric-astrometric survey of the galactic bulge, with the monitoring of about 120000 stars in 12 windows uniformly distributed in galactic latitude and longitude (Blanco & Terndrup, 1989 e Blanco, 1988) never before submitted to this kind of survey. For this purpose, we have used the IAG/USP CCD Meridian Circle of the Abrah\~ao de Moraes Observatory. The main objective of this work is the identification and classification of variable objects. In this work we present the set up and development of the necessary tools for a project like this and the posterior analysis of our data. We briefly describe the construction of a program to organize and detect variables among the observed stars, including real time alerts (for variations greater than 0.3 magnitudes). The preliminary analysis after the processing of 76 nights of observation yielded 479 variable stars, from which 96.7 % of them are new. We discuss the preliminary classification of this variables, based on: a) the observed amplitude of variation; b) the shape of light curve; c) the expected variable classes among our data and d) the calculated periods, whenever possible. Finally, we discuss the future perspectives for the project and for the applications and analysis of the discovered variable stars.Comment: 10 pages, 14 figures. Accepted by A&A

    High Resolution 4.7 um Keck/NIRSPEC Spectra of Protostars. I: Ices and Infalling Gas in the Disk of L1489 IRS

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    We explore the infrared M band (4.7 um) spectrum of the class I protostar L1489 IRS in the Taurus Molecular Cloud. This is the highest resolution wide coverage spectrum at this wavelength of a low mass protostar observed to date (R=25,000; Dv=12 km/s). Many narrow absorption lines of gas phase 12CO, 13CO, and C18O are detected, as well as a prominent band of solid 12CO. The gas phase 12CO lines have red shifted absorption wings (up to 100 km/s), likely originating from warm disk material falling toward the central object. The isotopes and the 12CO line wings are successfully fitted with a contracting disk model of this evolutionary transitional object (Hogerheijde 2001). This shows that the inward motions seen in millimeter wave emission lines continue to within ~0.1 AU from the star. The colder parts of the disk are traced by the prominent CO ice band. The band profile results from CO in 'polar' ices (CO mixed with H2O), and CO in 'apolar' ices. At the high spectral resolution, the 'apolar' component is, for the first time, resolved into two distinct components, likely due to pure CO and CO mixed with CO2, O2 and/or N2. The ices have probably experienced thermal processing in the upper disk layer traced by our pencil absorption beam: much of the volatile 'apolar' ices has evaporated and the depletion factor of CO onto grains is remarkably low (~7%). This study shows that high spectral resolution 4.7 um observations provide important and unique information on the dynamics and structure of protostellar disks and the evolution of ices in these disks.Comment: 11 pages, 6 figures Scheduled to appear in ApJ 568 n2, 1 April 200

    Visiting experiences and behavioural types in cultural audiences: an analysis of two museums in Lisbon

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    Audiences of cultural events are subject to diverse kinds of experiences in their exercise, which de termine the structure of their to structure their consumption practices and cultural habits. Mapping and analysing visitors’ experiences and their visiting styles is thus fundamental tocenhance museums’ offer appeal. Drawing on a conceptual framework which identifies four main kinds of experiences in cultural practices - (i) intellectual experience (ii) emotional experience; (iii) social experience; and (iv) recreational experience, the audiences of two museums in the city of Lisbon (Fado Museum and Puppets Museum) are analysed in this paper. Considering a typology of diverse audience categories (permanent collection, temporary exhibitions, other events), a detailed study of the assessment of different experiences is pursued, with the aim to confront and identify relevant discriminant categories such as socio-demographic characteristics (e.g. age, gender, qualifications, professional status, nationality, residence, previous artistic practices) and cultural habits (considering their visits to other cultural facilities and events). Considering the conclusions, some policy-oriented recommendations from this analysis are discussed.info:eu-repo/semantics/publishedVersio

    Visiting experiences and behavioural types in cultural audiences: an analysis of two museums in Lisbon

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    This paper was conceived within the scope of a wider study conducted by DINAMIA’CET-IUL for EGEAC (Lisbon Municipality’s Enterprise for Management of Cultural Facilities and Cultural Animation). The authors acknowledge the contributions of all participants involved in the study, particularly to the teams of the two museums. Versions of this paper were presented at the 18th International Conference on Cultural Economics (ACEI 2014), ESG-UQAM, Montreal, Canada, 24th-27th June 2014, and at the XXIV International Conference of RESER “Services and New Societal Challenges: Innovation for Sustainable Growth and Welfare”, Helsinki, Finland, September 11th-13th 2014.Audiences of cultural events are subject to diverse kinds of experiences in their exercise, which are determinant to structure their consumption practices and cultural habits. Mapping and analysing visitors’ experiences and their visiting styles is thus fundamental to enhance museums’ offer. Drawing on a conceptual framework which identifies four main kinds of experiences in cultural practices - (i) intellectual experience (ii) emotional experience; (iii) social experience; and (iv) recreational experience, the audiences of two museums in the city of Lisbon (Fado Museum and Puppets Museum) are analysed in this paper. Considering a typology of diverse audience categories (permanent collection, temporary exhibitions, other events), a detailed study of the assessment of different experiences is pursued, with the aim to confront and identify relevant discriminant categories such as socio-demographic characteristics (e.g. age, gender, qualifications, professional status, nationality, residence, previous artistic practices) and cultural habits (considering their visits to other cultural facilities and events). The final aim is to draw some policy-oriented recommendations from this analysis.FC

    Liquid crystal anchoring transitions on aligning substrates processed by plasma beam

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    We observe a sequence of the anchoring transitions in nematic liquid crystals (NLC) sandwiched between the hydrophobic polyimide substrates treated with the plasma beam. There is a pronounced continuous transition from homeotropic to low tilted (nearly planar) alignment with the easy axis parallel to the incidence plane of the plasma beam (the zenithal transition) that takes place as the exposure dose increases. In NLC with positive dielectric anisotropy, a further increase in the exposure dose results in in-plane reorientation of the easy axis by 90 degrees (the azimuthal transition). This transition occurs through the two-fold degenerated alignment characteristic for the second order anchoring transitions. In contrast to critical behavior of anchoring, the contact angle of NLC and water on the treated substrates monotonically declines with the exposure dose. It follows that the surface concentration of hydrophobic chains decreases continuously. The anchoring transitions under consideration are qualitatively interpreted by using a simple phenomenological model of competing easy axes which is studied by analyzing anchoring diagrams of the generalized polar and non-polar anchoring models.Comment: revtex4, 18 pages, 10 figure

    Introdução e avaliação de forrageiras no município de Santana do Araguaia, Estado do Parå.

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