922 research outputs found

    A Simplified Method to Select Combined Energy Systems

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    The European Union aims to ensure that investment in energy efficiency measures is cost- effective. Thus, the minimum energy performance requirements of buildings must follow the so-called cost-optimal levels. It is known that the impact of a specific measure on the energy performance is affected by others measures when implemented simultaneously, influencing its profitability. For this reason, the profitability of a given package of measures cannot result from the simple sum of potential benefits of each measure. Consequently, to define a cost-optimal solution it is needed to run a great amount of combinations, implying an expensive computational effort. In order to help with the selection of the energy systems, this work proposes a simplified method for selecting heating and domestic hot water systems as a function of the following variables: initial investment, maintenance cost, energy needs and cost, and efficiency of energy systems. The proposed method is user-friendly and can assist various stakeholders: policy makers, energy experts, suppliers of products and services and building owners.Sérgio Tadeu is grateful for the financial support provided by the Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP, through grant PIPE - 2016/00880-9 (Brazil). Márcio Gonçalves is grateful for the support by the doctoral FCT grant PD/BD/135194/2017. This work was framed within the project Expert A+ (POCI-01-0246-FEDER-026751) funded by Portugal 2020 through the COMPETE 2020 programme

    To boldly gulp: standard metabolic rate and boldness have context-dependent influences on risk-taking to breathe air in a catfish

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    The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O2 uptake (ṀO2,air) and the percentage of RMR obtained from air (%ṀO2,air), were influenced by individual standard metabolic rate (SMR) and boldness. In particular, whether any influence varied with resource availability (normoxia versus hypoxia) or relative fear of predation (day versus night). Individual SMR, derived from respirometry, had an overall positive influence on ṀO2,air across all contexts but a positive influence on %ṀO2,air only in hypoxia. Thus, a pervasive effect of SMR on air breathing became most acute in hypoxia, when individuals with higher O2 demand took proportionally more risks. Boldness was estimated as time required to resume air breathing after a fearful stimulus in daylight normoxia (Tres). Although Tres had no overall influence on ṀO2,air or %ṀO2,air, there was a negative relationship between Tres and %ṀO2,air in daylight, in normoxia and hypoxia. There were two Tres response groups, ‘bold’ phenotypes with Tres below 75 min (N=13) which, in daylight, breathed proportionally more air than ‘shy’ phenotypes with Tres above 115 min (N=16). Therefore, individual boldness influenced air breathing when fear of predation was high. Thus, individual energy demand and personality did not have parallel influences on the emergent tendency to take risks to obtain a resource; their influences varied in strength with context

    Interplay of tidal evolution and stellar wind braking in the rotation of stars hosting massive close-in planets

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    This paper deals with the application of the creep tide theory (Ferraz-Mello, Cel. Mech. Dyn. Astron. vol. 116, 109, 2013) to the study of the rotation of stars hosting massive close-in planets. The stars have nearly the same tidal relaxation factors as gaseous planets and the evolution of their rotation is similar to that of close-in hot Jupiters: they tidally evolve towards a stationary solution. However, stellar rotation may also be affected by stellar wind braking. Thus, while the rotation of a quiet host star evolves towards a stationary attractor with a frequency (1+6e21+6e^2) times the orbital mean-motion of the companion, the continuous loss of angular momentum in an active star displaces the stationary solution towards slower values: Active host stars with big close-in companions tend to have rotational periods larger than the orbital periods of their companions. The study of some hypothetical examples shows that because of tidal evolution, the rules of gyrochronology cannot be used to estimate the age of one system with a large close-in companion, no matter if the star is quiet or active, if the current semi-major axis of the companion is smaller than 0.03--0.04 AU. Details on the evolution of the systems: CoRoT LRc06E21637, CoRoT-27, Kepler-75, CoRoT-2, CoRoT-18, CoRoT-14 and on hypothetical systems with planets of mass 1--4 M_Jup in orbit around a star similar to the Sun are given.Comment: 22 pages, 8 figures; Publication in Ap

    Characterization and Glass Formation of JSC-1 Lunar and Martian Soil Simulants

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    The space exploration mission of NASA requires human and robotic presence for long duration beyond the low earth orbit (LEO), especially on Moon and Mars. Developing a human habitat or colony on these planets would require a diverse range of materials, whose applications would range from structural foundations, (human) life support, (electric) power generation to components for scientific instrumentations. A reasonable and cost-effective approach for fabricating the materials needed for establishing a self-sufficient human outpost would be to primarily use local (in situ) resources on these planets. Since ancient times, glass and ceramics have been playing a vital role on human civilization. A long term project on studying the feasibility of developing glass and ceramic materials has been undertaken using Lunar and Martian soil simulants (JSC-1) as developed by Johnson Space Center. The first step in this on-going project requires developing a data base on results that fully characterize the simulants to be used for further investigations. The present paper reports characterization data of both JSC-1 Lunar and JSC Mars-1 simulants obtained up to this time via x-ray diffraction analysis, scanning electron microscopy, thermal analysis (DTA, TGA) and chemical analysis. The critical cooling rate for glass formation for the melts of the simulants was also measured in order to quantitatively assess the glass forming tendency of these melts. The importance of the glasses and ceramics developed using in-situ resources for constructing human habitats on Moon or Mars is discussed

    Apresentação incomum de hepatite induzida por Epstein-Barr Virus em criança de 15 meses de idade

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    Objective: We report an atypical case of hepatitis in an infant that could be helpful to physicians of various specialties, as it demonstrates an atypical clinical and laboratorial manifestation of a disease not so common at that age and that could have gone undiagnosed. Case Description: A 15-month-old female, immunocompetent patient was referred to the hospital with a 3-day history of fever, vomiting, and diarrhea. The patient presented with alternation between sleepiness and irritation associated with rapid increase in serum liver enzymes levels, but no jaundice. Neurologic evaluation showed no meningeal signs and no encephalic morphological abnormalities were observed in a cranial CT scan. Treatment consisted of symptomatic medication and daily evaluation for signs of hepatic encephalopa- thy or bleeding. A serological panel showed negative IgM but positive IgG reactivity against Cytomega- lovirus (CMV) and IgM and IgG negative immunoreactivity against HAV. She was not tested for Hepatits B (HBV) or Hepatits C (HCV). Positive immunoreactivity against the Epstein-Barr virus capsid antigen (EBV VCA) IgM and negative reactivity against IgG, indicated a diagnosis of EBV-induced acute hepatitis. The patient was discharged asymptomatic after 11 days, with decreasing serum liver enzymes levels. A 15-day follow up evidenced complete remission of symptoms and normalized laboratory tests. Comments: Hepatic involvement in infections by Epstein-Barr Virus is common, presenting with moderate and transient increase in liver enzymes. It can go undetected and resolve spontaneously, while clinical manifestations of hepatitis are infrequent. In this report, we present an unusual case of a pediatric patient with hepatitis induced by EBV infection, along with a review of the literature. According to our search, no other EBV-induced hepatitis case reports have been published involving an immunocompetent patient under 2 years of ageObjetivo: Este relato de uma hepatite em um paciente pediátrico pode trazer benefícios para médicos de diversas especialidades, pois ele demonstra um quadro clínico e laboratorial atípicos de uma doença não tão comum nessa faixa etária e que poderia não ter sido diagnosticada. Descrição do Caso: Uma paciente, de 15 meses de idade, foi referenciada ao hospital com história de 3 dias de febre, vômitos e diarréia. A paciente apresentava alternância entre sonolência e irritação associada com rápida elevação das enzimas hepáticas, mas sem icterícia. Ao exame neurológico não foram evidenciados sinais meníngeos e a tomografia computadorizada de crânio não apresentou altera- ções. O tratamento consistiu em medicação sintomática junto à avaliação diária dos sinais de encefalopatia hepática ou sangramentos. O painel sorológico foi de IgM negativo e IgG positivo para Citomegalovirus (CMV) e IgM e IgG negativos para Anti-HAV. Em contraste, encontrou-se no soro IgM Imunorreativa contra o antígeno do capsídeo do vírus Epstein-Barr (EBV VCA), o que confirmou um diagnóstico de hepatite pelo EBV. A paciente recebeu alta hospitalar assintomática após 11 dias de internação, com declínio dos valores séricos das transaminases. Um acompanhamento após 15 dias da alta evidenciou completa remissão dos sintomas. Comentários: O envolvimento do fígado com infecções pelo vírus Epstein-Barr é comum, apresentando elevações moderadas e transitórias das enzimas hepáticas. Ela pode não ser detectada e ser autolimitada, enquanto manifestações hepáticas são infrequentes. Nesse relato de caso, é apresentado um quadro pediátrico atípico de um paciente que desenvolveu hepatite induzido pela infecção por EBV, além de uma revisão na literatura. De acordo com nossa busca, nenhum outro caso de hepatite induzida por EBV foi publicado envolvendo um paciente imunocompetente com idade inferior a 2 ano

    Formation and evolution of the two 4/3 resonant giants planets in HD 200946

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    It has been suggested that HD 200964 is the first exoplanetary system with two Jovian planets evolving in the 4/3 mean- motion resonance. Previous scenarios to simulate the formation of two giant planets in the stable 4/3 resonance configuration have failed. Moreover, the orbital parameters available in the literature point out an unstable configuration of the planetary pair. The purpose of this paper is i) to determine the orbits of the planets from the RV measurements and update the value of the stellar mass (1.57 M), ii) to analyse the stability of the planetary evolution in the vicinity and inside the 4/3 MMR, and iii) to elaborate a possible scenario for the formation of systems in the 4/3 MMR. The results of the formation simulations are able to very closely reproduce the 4/3 resonant dynamics of the best-fit config- uration obtained in this paper. Moreover, the confidence interval of the fit matches well with the very narrow stable region of the 4/3 mean-motion resonance. The formation process of the HD 200964 system is very sensitive to the planetary masses and protoplanetary disk parameters. Only a thin, flat disk allows the embryo-sized planets to reach the 4/3 resonant configuration. The stable evolution of the resonant planets is also sensitive to the mass of the central star, because of overlapping high-order resonances inside the 4/3 resonance. Regardless of the very narrow domain of stable motion, the confidence interval of our fit closely matches the stability area

    On planetary mass determination in the case of super-Earths orbiting active stars. The case of the CoRoT-7 system

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    This investigation uses the excellent HARPS radial velocity measurements of CoRoT-7 to re-determine the planet masses and to explore techniques able to determine mass and elements of planets discovered around active stars when the relative variation of the radial velocity due to the star activity cannot be considered as just noise and can exceed the variation due to the planets. The main technique used here is a self-consistent version of the high-pass filter used by Queloz et al. (2009) in the first mass determination of CoRoT-7b and CoRoT-7c. The results are compared to those given by two alternative techniques: (1) The approach proposed by Hatzes et al. (2010) using only those nights in which 2 or 3 observations were done; (2) A pure Fourier analysis. In all cases, the eccentricities are taken equal to zero as indicated by the study of the tidal evolution of the system; the periods are also kept fixed at the values given by Queloz et al. Only the observations done in the time interval BJD 2,454,847 - 873 are used because they include many nights with multiple observations; otherwise it is not possible to separate the effects of the rotation fourth harmonic (5.91d = Prot/4) from the alias of the orbital period of CoRoT-7b (0.853585 d). The results of the various approaches are combined to give for the planet masses the values 8.0 \pm 1.2 MEarth for CoRoT-7b and 13.6 \pm 1.4 MEarth for CoRoT 7c. An estimation of the variation of the radial velocity of the star due to its activity is also given.The results obtained with 3 different approaches agree to give masses larger than those in previous determinations. From the existing internal structure models they indicate that CoRoT-7b is a much denser super-Earth. The bulk density is 11 \pm 3.5 g.cm-3 . CoRoT-7b may be rocky with a large iron core.Comment: 12 pages, 11 figure

    A IMPORTÂNCIA DA METODOLOGIA DA PESQUISA PARA A PRODUÇÃO DE CONHECIMENTO CIENTÍFICO NOS CURSOS DE PÓS-GRADUAÇÃO: A singularidade textual dos trabalhos científicos jurídicos

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    O presente trabalho contém uma análise crítica da construção do conhecimento científico com obediência a uma metodologia científica reconhecida e cristalizada. Desenvolve uma análise da importância da metodologia para a pesquisa de pós-graduação em direito e das dificuldades dos discentes na elaboração de Projetos de Pesquisa e Dissertações, sobretudo em relação aos problemas metodológicos e textuais. Apresenta igualmente uma análise da singularidade textual dos trabalhos acadêmicos jurídicos, abordando e demonstrando as causas deste processo. Portanto, evidencia a necessidade de mudança deste paradigma para garantir maior acessibilidade do conhecimento produzido e garantir o caráter científico das pesquisas jurídicas
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