2,690 research outputs found

    EDUCAÇÃO AMBIENTAL: EDUCAR OU INFORMAR?

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    A busca pelo questionado desenvolvimento sustentável requer reflexão sobre as ações praticadas em prol deste, no sentido que as mudanças só ocorrerão quando mudarmos nosso comportamento, quando realmente passarmos por um processo de internalização de novas crenças e valores rompendo com conceitos pré-estabelecidos, ou seja, por meio da educação. Educar é preparar para pensar certo, no sentido de tornar apto a agir, a mudar, a criar, inovar, criticar, a cooperar, a recomeçar ou voltar atrás se for preciso, a ter esperança e comprometimento com o futuro e, ainda, buscar o conhecimento. O verdadeiro objetivo da Educação está em orientar um novo sentido de viver e atuar valorizando acima de tudo a vida. ENVIROMENT EDUCACION: EDUCACION OR INFORMATION? Abstract The search for the so questioned sustainable development requires a reflection on the actions taken in prol of this, in the direction that the changes will only happen when we change our behavior, when we pass throught a process of internalization of new beliefs and values, breaking with daily pre-established concepts, through education. To educate is to prepare to correct thinking, in the way to become ready to act, to move, to create, to innovate, to criticize, to cooperate, to restart or to come back, if needed, to have hope and commitment with the future and, still, to search for knowledge. The real goal of Education is to guide new ways of living and to act respecting life above all

    Modeling and simulation of nuclear hybrid energy systems architectures

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    The transition toward a low-carbon energy system and the increasing penetration of variable renewable energy (VRE) sources translate into a pressing need for dispatchable and low-carbon power sources. Nuclear hybrid energy systems (NHES) exploit the synergies between nuclear power and other energy sources together with energy storage devices and a variety of electric and non-electric applications. The expected benefits range from a high flexibility being able to supporting an increasing penetration of the VRE while complying with the grid demand and constraints to an increased profitability brought by the production of commodities beyond electricity (e.g., hydrogen, heat, etc.). A dedicated framework must be developed to evaluate different NHES configurations, particularly with regard to the complex interconnections among the tightly coupled components. In this work, illustrative examples of NHES components were selected and modeled with the object-oriented modeling language Modelica and implemented in the Dymola simulation environment. The technologies considered in this study are a Small Modular Reactor (SMR) based on pressurized water technology, a thermal energy storage (TES) system, and an alkaline electrolyzer for hydrogen production. The dynamic models are then collected in a new Modelica library and assembled into a variety of NHES topologies using a plug-and-play approach. The time-dependent behavior of the NHES layout can be simulated under different operational contexts, enabling the monitoring of key process variables, supporting system design, exploring alternative control strategies, and analyzing different scenarios. The NHESs are investigated in two exemplary scenarios – one representing typical load conditions and the other featuring high VRE penetration – in order to demonstrate the viability of the proposed approach as an initial effort toward the development of a holistic framework for analyzing NHES. The dynamic models effectively met the analysis requirements, for instance, by tracking the production of commodities throughout each operational transient, which is an essential result for evaluating the performance of NHES. In this regard, efficiency is adopted as the figure of merit to compare the different NHES architectures, with simulation results indicating significant overall efficiency improvements in NHES incorporating TES and using nuclear heat to drive non-electric applications

    Testing the nature of S0 galaxies using planetary nebula kinematics in NGC 1023

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    We investigate the manner in which lenticular galaxies are formed by studying their stellar kinematics: an S0 formed from a fading spiral galaxy should display similar cold outer disc kinematics to its progenitor, while an S0 formed in a minor merger should be more dominated by random motions. In a pilot study to attempt to distinguish between these scenarios, we have measured the planetary nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the Planetary Nebula Spectrograph, we have detected and measured the line-of-sight velocities of 204 candidate PNe in the field of this galaxy. Out to intermediate radii, the system displays the kinematics of a normal rotationally-supported disc system. After correction of its rotational velocities for asymmetric drift, the galaxy lies just below the spiral galaxy Tully-Fisher relation, as one would expect for a fading system. However, at larger radii the kinematics undergo a gradual but major transition to random motion with little rotation. This transition does not seem to reflect a change in the viewing geometry or the presence of a distinct halo component, since the number counts of PNe follow the same simple exponential decline as the stellar continuum with the same projected disc ellipticity out to large radii. The galaxy's small companion, NGC 1023A, does not seem to be large enough to have caused the observed modification either. This combination of properties would seem to indicate a complex evolutionary history in either the transition to form an S0 or in the past life of the spiral galaxy from which the S0 formed. More data sets of this type from both spirals and S0s are needed in order to definitively determine the relationship between these types of system.Comment: Accepted for publication in MNRAS. Version with full resolution figure 1 can be found at http://www.nottingham.ac.uk/~ppzmrm/N1023_PNS.accepted.pd

    Dark-Matter Content of Early-Type Galaxies with Planetary Nebulae

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    We examine the dark matter properties of nearby early-type galaxies using planetary nebulae (PNe) as mass probes. We have designed a specialised instrument, the Planetary Nebula Spectrograph (PN.S) operating at the William Herschel telescope, with the purpose of measuring PN velocities with best efficiency. The primary scientific objective of this custom-built instrument is the study of the PN kinematics in 12 ordinary round galaxies. Preliminary results showing a dearth of dark matter in ordinary galaxies (Romanowsky et al. 2003) are now confirmed by the first complete PN.S datasets. On the other hand early-type galaxies with a "regular" dark matter content are starting to be observed among the brighter PN.S target sample, thus confirming a correlation between the global dark-to-luminous mass virial ratio (f_DM=M_DM/M_star) and the galaxy luminosity and mass.Comment: 5 pages, 2 figures. To appear in the proceedings of the IAU Symposium 244 "Dark Galaxies and Lost Baryons", Cardiff 25-29 June 2007, eds. J.I. Davies & M.J. Disne

    Start of SPIDER operation towards ITER neutral beams

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    Heating Neutral Beam (HNB) Injectors will constitute the main plasma heating and current drive tool both in ITER and JT60-SA, which are the next major experimental steps for demonstrating nuclear fusion as viable energy source. In ITER, in order to achieve the required thermonuclear fusion power gain Q=10 for short pulse operation and Q=5 for long pulse operation (up to 3600s), two HNB injectors will be needed [1], each delivering a total power of about 16.5 MW into the magnetically-confined plasma, by means of neutral hydrogen or deuterium particles having a specific energy of about 1 MeV. Since only negatively charged particles can be efficiently neutralized at such energy, the ITER HNB injectors [2] will be based on negative ions, generated by caesium-catalysed surface conversion of atoms in a radio-frequency driven plasma source. A negative deuterium ion current of more than 40 A will be extracted, accelerated and focused in a multi-aperture, multi-stage electrostatic accelerator, having 1280 apertures (~ 14 mm diam.) and 5 acceleration stages (~200 kV each) [3]. After passing through a narrow gas-cell neutralizer, the residual ions will be deflected and discarded, whereas the neutralized particles will continue their trajectory through a duct into the tokamak vessels to deliver the required heating power to the ITER plasma for a pulse duration of about 3600 s. Although the operating principles and the implementation of the most critical parts of the injector have been tested in different experiments, the ITER NBI requirements have never been simultaneously attained. In order to reduce the risks and to optimize the design and operating procedures of the HNB for ITER, a dedicated Neutral Beam Test Facility (NBTF) [4] has been promoted by the ITER Organization with the contribution of the European Union\u2019s Joint Undertaking for ITER and of the Italian Government, with the participation of the Japanese and Indian Domestic Agencies (JADA and INDA) and of several European laboratories, such as IPP-Garching, KIT-Karlsruhe, CCFE-Culham, CEA-Cadarache. The NBTF, nicknamed PRIMA, has been set up at Consorzio RFX in Padova, Italy [5]. The planned experiments will verify continuous HNB operation for one hour, under stringent requirements for beam divergence (< 7 mrad) and aiming (within 2 mrad). To study and optimise HNB performances, the NBTF includes two experiments: MITICA, full-scale NBI prototype with 1 MeV particle energy and SPIDER, with 100 keV particle energy and 40 A current, aiming at testing and optimizing the full-scale ion source. SPIDER will focus on source uniformity, negative ion current density and beam optics. In June 2018 the experimental operation of SPIDER has started

    The GAPS Programme with HARPS-N at TNG VIII: Observations of the Rossiter-McLaughlin effect and characterisation of the transiting planetary systems HAT-P-36 and WASP-11/HAT-P-10

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    We determine the true and the projected obliquity of HAT-P-36 and WASP-11/HAT-P-10 systems, respectively, which are both composed of a relatively cool star and a hot-Jupiter planet. Thanks to the high-resolution spectrograph HARPS-N, we observed the Rossiter-McLaughlin effect for both the systems by acquiring precise radial-velocity measurements during planetary transit events. We also present photometric observations comprising six light curves covering five transit events, obtained using three medium-class telescopes and the telescope-defocussing technique. One transit of WASP-11/HAT-P-10 was followed simultaneously from two observatories. The three transit light curves of HAT-P-36b show anomalies that are attributable to starspot complexes on the surface of the parent star, in agreement with the analysis of its spectra that indicate a moderate activity. By analysing the complete HATNet data set of HAT-P-36, we estimated the stellar rotation period by detecting a periodic photometric modulation in the light curve caused by star spots, obtaining Prot=15.3 days, which implies that the inclination of the stellar rotational axis with respect to the line of sight is 65 degree. We used the new spectroscopic and photometric data to revise the main physical parameters and measure the sky-projected misalignment angle of the two systems. We found \lambda=-14 degree for HAT-P-36 and \lambda=7 degree for WASP-11/HAT-P-10, indicating in both cases a good spin-orbit alignment. In the case of HAT-P-36, we also measured its real obliquity, which turned out to be 25 degrees.Comment: 18 pages, 14 figure

    Syndecan expressions in the human amnion and chorionic plate

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    The syndecan family consists of four distinct membrane glycoproteins in mammals. Syndecans control cell proliferation, differentiation, adhesion and migration through participation in cell-cell interactions, anchorage of cells to the extracellular environment, and modulation of multiple growth factors. Therefore, syndecans may play a pivotal role in the regulation of cell behaviour depending on the cellular microenvironment. Here, we demonstrate that syndecan-1, syndecan-2 and syndecan-4 are expressed in fetal membrane tissue with different immunolocalizations. Syndecan-1 is expressed in the amniotic epithelium, localizing at basolateral cell surfaces. Syndecan-2 and syndecan-4, in contrast, are mostly localized in intracellular compartments, in the extravillous cytotrophoblastic cells and in some fibroblasts of the chorionic plate as well as in the amniotic epithelial cells. In the latter, syndecan-4 is mainly localized in the apical part of the cells. Our results strongly suggest a key role of syndecan-1, syndecan-2 and syndecan-4 in the determination of structural and functional characteristics of human amnion and chorionic plate. Since the solute exchanges between fetus and mother take place in fetal membranes, our data suggest that syndecans are important players in the placenta for the establishment of the fetal-maternal inter-communication
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