14,551 research outputs found

    Spontaneous CP Violation in the Next-to-Minimal Supersymmetric Standard Model Revisited

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    We re-examine spontaneous CP violation at the tree level in the context of the next-to-minimal supersymmetric standard model (NMSSM) with two Higgs doublets and a gauge singlet field. We analyse the most general Higgs potential without a discrete Z_3 symmetry, and derive an upper bound on the mass of the lightest neutral Higgs boson consistent with present experimental data. We investigate, in particular, its dependence on the admixture and CP-violating phase of the gauge singlet field, as well as on tan(beta). To assess the viability of the spontaneous CP violation scenario, we estimate epsilon_K by applying the mass insertion approximation. We find that a non-trivial flavour structure in the soft-breaking A terms is required to account for the observed CP violation in the neutral kaon sector. Furthermore, combining the minimisation conditions for spontaneous CP violation with the constraints coming from K0-K0bar mixing, we find that the upper bound on the lightest Higgs-boson mass becomes stronger. We also point out that the electric dipole moments of electron and neutron are a serious challenge for SUSY models with spontaneous CP violation.Comment: 19 pages, LaTeX2e, 5 figures; matches the published versio

    Future dynamics in f(R) theories

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    The f(R)f(R) gravity theories provide an alternative way to explain the current cosmic acceleration without invoking dark energy matter component. However, the freedom in the choice of the functional forms of f(R)f(R) gives rise to the problem of how to constrain and break the degeneracy among these gravity theories on theoretical and/or observational grounds. In this paper to proceed further with the investigation on the potentialities, difficulties and limitations of f(R)f(R) gravity, we examine the question as to whether the future dynamics can be used to break the degeneracy between f(R)f(R) gravity theories by investigating the future dynamics of spatially homogeneous and isotropic dust flat models in two f(R)f(R) gravity theories, namely the well known f(R)=R+αRnf(R) = R + \alpha R^{n} gravity and another by A. Aviles et al., whose motivation comes from the cosmographic approach to f(R)f(R) gravity. To this end we perform a detailed numerical study of the future dynamic of these flat model in these theories taking into account the recent constraints on the cosmological parameters made by the Planck team. We show that besides being powerful for discriminating between f(R)f(R) gravity theories, the future dynamics technique can also be used to determine the fate of the Universe in the framework of these f(R)f(R) gravity theories. Moreover, there emerges from our numerical analysis that if we do not invoke a dark energy component with equation-of-state parameter ω<1\omega < -1 one still has dust flat FLRW solution with a big rip, if gravity deviates from general relativity via f(R)=R+αRnf(R) = R + \alpha R^n . We also show that FLRW dust solutions with f<0f''<0 do not necessarily lead to singularity.Comment: 12 pages, 8 figures. V2: Generality and implications of the results are emphasized, connection with the recent literature improved, typos corrected, references adde

    On Exact and Approximate Solutions for Hard Problems: An Alternative Look

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    We discuss in an informal, general audience style the da Costa-Doria conjecture about the independence of the P = NP hypothesis and try to briefly assess its impact on practical situations in economics. The paper concludes with a discussion of the Coppe-Cosenza procedure, which is an approximate, partly heuristic algorithm for allocation problems.P vs. NP , allocation problem, assignment problem, traveling salesman, exact solution for NP problems, approximate solutions for NP problems, undecidability, incompleteness

    Caracterização do sistema de produção de leite predominante no sudeste paraense.

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    Perfil da produção; O produtor; A propriedade; Terras; Benfeitorias, máquinas e equipamentos; Sistema de produção; Composição do rebanho; Alimentação do rebanho; Manejo do rebanho; Produção e produtividade; Coeficientes zootécnicos; Recursos humanos; Receita bruta; Comercialização; Aquisição de insumos; Economia da produção.bitstream/item/63562/1/Oriental-Doc142.PD

    The Environment and Nature of the Class I Protostar Elias 29: Molecular Gas Observations and the Location of Ices

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    A (sub-)millimeter line and continuum study of the Class I protostar Elias 29 in the ρ Ophiuchi molecular cloud is presented whose goals are to understand the nature of this source and to locate the ices that are abundantly present along this line of sight. Within 15"-60" beams, several different components contribute to the line emission. Two different foreground clouds are detected, an envelope/disk system and a dense ridge of HCO^+-rich material. The latter two components are spatially separated in millimeter interferometer maps. We analyze the envelope/disk system by using inside-out collapse and flared disk models. The disk is in a relatively face-on orientation (<60°), which explains many of the remarkable observational features of Elias 29, such as its flat spectral energy distribution, its brightness in the near-infrared, the extended components found in speckle interferometry observations, and its high-velocity molecular outflow. It cannot account for the ices seen along the line of sight, however. A small fraction of the ices is present in a (remnant) envelope of mass 0.12-0.33 M_☉, but most of the ices (~70%) are present in cool (T < 40 K) quiescent foreground clouds. This explains the observed absence of thermally processed ices (crystallized H_2O) toward Elias 29. Nevertheless, the temperatures could be sufficiently high to account for the low abundance of apolar (CO, N_2, O_2) ices. This work shows that it is crucial to obtain spectrally and spatially resolved information from single-dish and interferometric molecular gas observations in order to determine the nature of protostars and to interpret Infrared Space Observatory and future Space Infrared Telescope Facility observations of ices and silicates along a pencil beam

    Photospheric properties and fundamental parameters of M dwarfs

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    M dwarfs are an important source of information when studying and probing the lower end of the Hertzsprung-Russell (HR) diagram, down to the hydrogen-burning limit. Being the most numerous and oldest stars in the galaxy, they carry fundamental information on its chemical history. The presence of molecules in their atmospheres, along with various condensed species, complicates our understanding of their physical properties and thus makes the determination of their fundamental stellar parameters more challenging and difficult. The aim of this study is to perform a detailed spectroscopic analysis of the high-resolution H-band spectra of M dwarfs in order to determine their fundamental stellar parameters and to validate atmospheric models. The present study will also help us to understand various processes, including dust formation and depletion of metals onto dust grains in M dwarf atmospheres. The high spectral resolution also provides a unique opportunity to constrain other chemical and physical processes that occur in a cool atmosphere The high-resolution APOGEE spectra of M dwarfs, covering the entire H-band, provide a unique opportunity to measure their fundamental parameters. We have performed a detailed spectral synthesis by comparing these high-resolution H-band spectra to that of the most recent BT-settl model and have obtained fundamental parameters such as effective temperature, surface gravity, and metallicity (Teff, log g and [Fe/H]) respectively.Comment: 15 pages, 10 figures, accepted for publication in A&

    Alimentos funcionais: conceitos básicos.

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    Unusual association of diseases/symptoms - Campomelic dysplasia and malignant hyperthermia

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    Campomelic dysplasia (CD) is a rare clinical entity, usually fatal in the first year of life. It is characterised by bowing and angulations of long bones, along with other congenital anomalies. The occurrence of malignant hyperthermia is rare, but it has been associated with skeletal dysplasias. The authors present the case of a boy, born at 40 weeks of gestational age, with multiple congenital anomalies and subsequently diagnosed with CD, who died at 16 months of age as a consequence of malignant hyperthermia.info:eu-repo/semantics/publishedVersio

    Measurement errors and uncertainty estimation of an experimental set up using a 2D PIV technique

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    The study of the flow interaction and the heat transfer between air jets and a surface is of paramount importance in industrial processes that apply multiple air jet impingement. To ensure a good performance of the process, high heat transfer rates and uniformization of the flow over the target plate are required. To perform this analysis, a PIV technique was implemented for the measurement of the velocity fields of the flow. However, as any real experiment, the values recorded by the PIV method are subjected to several errors that compromise the reliability and accuracy of the measurements. These errors can have different sources, from the installation and alignment to the particles seeding and calibration procedure. To determine an interval that contains the measurement error, the uncertainty quantification is crucial. In that sense, this paper focus on the identification of measurement errors and uncertainty quantification of an experimental set up specially built for the analysis of the interaction between a non-isothermal jets and non-flat surfaces moving perpendicularly to the jet axis. To ensure the reliability of the results, preliminary tests were performed to guarantee a uniform and stable flow and to determine the range and conditions of operation. In addition, this work presents an analysis of the system, and the source of errors are identified, quantified and, when possible, corrected. The particle seeding, which consists of olive oil droplets, is characterized and its efficiency for the flow tracking is analysed. The test facility was tested to fully characterize the flow field in terms of mean velocity profile and turbulence intensity over a wide range of Reynolds numbers and temperature. Several velocity fields are then measured until convergence of the flow quantities is reached. The combination of these measurements with high spatial resolution and low measurement errors allow to obtain accurate and precise measurement values.Portuguese Foundation for Science and Technology (FCT) through the Research Grant PD/BD/128216/2016. This work has been supported by FCT within the Project Scope UID/CEC/00319/2019 (ALGORITMI) and Project Scope UID/EMS/04077/2019 (METRICS)
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