933 research outputs found

    Two and Three Nucleon Forces

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    Chiral symmetry allows two and three nucleon forces to be treated in a single theoretical framework. We discuss two new features of this research programme at \cO(q^4) and the consistency of the overall chiral picture.Comment: Talk at the 18th International IUPAP Conference on Few-Body Problems in Physics, Santos, Brazi

    Inventariação e propagação de Thymus mastichina na Beira Interior

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    Integrado no Programa Agro, Medida 8.1, Projecto nº 800, foram elaborados estudos de distribuição e propagação da espécie Thymus mastichina L., existentes espontaneamente na Beira Interior. Foram avaliadas seis zonas ecológicas distintas denominadas Vale do Tejo, Beira Interior Sul, Cova da Beira, Beira Interior Norte, Serra da Estrela e Serra da Gardunha. Durante dois anos fez-se prospecção no campo em cada zona ecológica e recolheu-se material vegetal. Realizaram-se ensaios de germinação em laboratório em condições de temperatura alterna 10º/20ºC (dia) e temperatura constante 23ºC (dia), com fotoperíodo de 8 e 16 horas/dia, respectivamente. Testou-se ainda a capacidade germinativa em estufa, na Primavera e efectuaram-se ensaios de enraizamento, com estacas terminais, em condições de Outono/Inverno e Primavera/Verão. Na Beira Interior foram encontrados 36 locais onde se verificou a ocorrência de Thymus mastichina. Em cada zona ecológica onde foram encontrados indivíduos da espécie em estudo, foi seleccionado um local para recolha de 20 plantas-mãe, que foram posteriormente instaladas no campo de caracterização/demonstração da ESACB. Nos ensaios de germinação verificaram-se taxas entre os 80% e 94% em laboratório e entre os 76% e 84%, em viveiro. Nos ensaios de propagação vegetativa de estacas terminais obtiveram-se taxas de enraizamento entre os 20% e 100%

    Analysis of three-nucleon forces effects in the A=3A=3 system

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    Using modern nucleon-nucleon interactions in the description of the A=3,4A=3,4 nuclear systems the χ2\chi^2 per datum results to be much bigger than one. In particular it is not possible to reproduce the three- and four-nucleon binding energies and the ndn-d scattering length simultaneously. This is one manifestation of the necessity of including a three-nucleon force in the nuclear Hamiltonian. In this paper we perform an analysis of some, widely used, three-nucleon force models. We analyze their capability to describe the aforementioned quantities and, to improve their description, we propose modifications in the parametrization of the models. The effects of these new parametrization are studied in some polarization observables at low energies.Comment: 10 pages, to be published in Few-Body Systems. Presented at the workshop on "Relativistic Description of Two- and Three-body Systems in Nuclear Physics" ECT* Trento, 19 - 23 October 200

    πΞ\pi\Xi phase shifts and CP Violation in ΩπΞ{\Omega\to\pi\Xi} Decay

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    In the study of CP violation signals in {\O}\to\pi\Xi nonleptonic decays, the strong JJ=3/2 PP and DD phase shifts for the πΞ\pi\Xi final-state interactions are needed. These phases are calculated using an effective Lagrangian model, including Ξ\Xi, Ξ\Xi^*(1530), ρ\rho and the σ\sigma-term, in the intermediate states. The σ\sigma-term is calculated in terms of the scalar form factor of the baryon.Comment: 6 pages, 2 figure

    MINIMIZATION OF PHENOL AND AMMONIACAL NITROGEN IN REFINERY WASTEWATER EMPLOYING BIOLOGICAL TREATMENT

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    Wastewater from refineries is usually characterized by presence of phenol and ammoniacal nitrogen. The aim of this work was to search for a refinery wastewater minimization employing a biological technology to reduce these pollutants. Experimental data was obtained by treating a synthetic wastewater in a sequencing batch reactor (SBR) operating on different operational schemes for batch scheduling. COD, nitrate, ammonia, phosphate and phenol were monitored as well as dissolved oxygen, pH, level and redox potential through a supervisory control software. Reductions of 95 % were achieved for different concentrations of NH4 + and phenol, providing an effluent acceptable by Brazilian environmental legislation

    Numerical convergence of the block-maxima approach to the Generalized Extreme Value distribution

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    In this paper we perform an analytical and numerical study of Extreme Value distributions in discrete dynamical systems. In this setting, recent works have shown how to get a statistics of extremes in agreement with the classical Extreme Value Theory. We pursue these investigations by giving analytical expressions of Extreme Value distribution parameters for maps that have an absolutely continuous invariant measure. We compare these analytical results with numerical experiments in which we study the convergence to limiting distributions using the so called block-maxima approach, pointing out in which cases we obtain robust estimation of parameters. In regular maps for which mixing properties do not hold, we show that the fitting procedure to the classical Extreme Value Distribution fails, as expected. However, we obtain an empirical distribution that can be explained starting from a different observable function for which Nicolis et al. [2006] have found analytical results.Comment: 34 pages, 7 figures; Journal of Statistical Physics 201

    Fitting the integrated Spectral Energy Distributions of Galaxies

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    Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

    The Milky Way Bulge: Observed properties and a comparison to external galaxies

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    The Milky Way bulge offers a unique opportunity to investigate in detail the role that different processes such as dynamical instabilities, hierarchical merging, and dissipational collapse may have played in the history of the Galaxy formation and evolution based on its resolved stellar population properties. Large observation programmes and surveys of the bulge are providing for the first time a look into the global view of the Milky Way bulge that can be compared with the bulges of other galaxies, and be used as a template for detailed comparison with models. The Milky Way has been shown to have a box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an additional spheroidal component. In this review we summarise the global chemical abundances, kinematics and structural properties that allow us to disentangle these multiple components and provide constraints to understand their origin. The investigation of both detailed and global properties of the bulge now provide us with the opportunity to characterise the bulge as observed in models, and to place the mixed component bulge scenario in the general context of external galaxies. When writing this review, we considered the perspectives of researchers working with the Milky Way and researchers working with external galaxies. It is an attempt to approach both communities for a fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure

    Honey Bee (Apis mellifera L.) Broods: Composition, Technology and Gastronomic Applicability

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    Honey bee broods (larvae and pupae) can be consumed as human food, offering a rich nutritional value. Therefore, the objective of this work was to present an overview of the nutritional value of the honey bee brood and its gastronomic potential. The results indicated that honey bee broods are rich in protein (including essential amino acids), fat (essentially saturated and monounsaturated fatty acids), carbohydrates, vitamin C and those of the B complex, and minerals such as potassium, magnesium, calcium, and phosphorous. The results further highlight some variability according to the stage of development, with increasing content of fat and protein and decreasing carbohydrates from the larval to the pupal stages. The production of the honey bee brood in the hive, as well as its removal, can impact the wellbeing of the hive. This limits the production potential of the brood aimed at application for gastronomic purposes. The consumption and purchase of honey bee broods as food may be accessible in specialised markets where, for example, ethnic communities consume this type of food. However, in some markets, insects or products produced from insects are not readily accepted because of neophobia and disgust. The role of culinary chefs allied to traditional ways of preparing culinary dishes that include honey bee broods are relevant to motivate more people in western societies to consume of these types of food products.info:eu-repo/semantics/publishedVersio

    Honey bee (Apis mellifera L.) broods: composition, technology and gastronomic applicability

    Get PDF
    Honey bee broods (larvae and pupae) can be consumed as human food, offering a rich nutritional value. Therefore, the objective of this work was to present an overview of the nutritional value of the honey bee brood and its gastronomic potential. The results indicated that honey bee broods are rich in protein (including essential amino acids), fat (essentially saturated and monounsaturated fatty acids), carbohydrates, vitamin C and those of the B complex, and minerals such as potassium, magnesium, calcium, and phosphorous. The results further highlight some variability according to the stage of development, with increasing content of fat and protein and decreasing carbohydrates from the larval to the pupal stages. The production of the honey bee brood in the hive, as well as its removal, can impact the wellbeing of the hive. This limits the production potential of the brood aimed at application for gastronomic purposes. The consumption and purchase of honey bee broods as food may be accessible in specialised markets where, for example, ethnic communities consume this type of food. However, in some markets, insects or products produced from insects are not readily accepted because of neophobia and disgust. The role of culinary chefs allied to traditional ways of preparing culinary dishes that include honey bee broods are relevant to motivate more people in western societies to consume of these types of food products.info:eu-repo/semantics/publishedVersio
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