Consequências da monocultura de braquiárias e da invasão de cambarazais e algodoais sobre a ictiofauna de alagados no Pantanal.

As áreas inundáveis do Pantanal são importantes ambientes de alimentação, crescimento e desova para a ictiofauna. A vegetação das áreas inundáveis passa por fortes mudanças, em parte causadas por oscilações naturais do nível hidrológico, em parte ocasionada pelo manejo humano da paisagem. São exemplos dessas mudanças, naturais ou antrópicas, a substituição de campos nativos pela expansão de algodoais (Ipomoea carnea), cambarazais (Vochysia divergens) e pela introdução das forrageiras Brachiaria spp. Avaliamos as consequências dessas substituições sobre a ictiofauna em áreas alagáveis do Pantanal Norte. Comparamos riqueza de espécies, biomassa e abundância das ictiocenoses coletadas em 30 parcelas com 25 m2. Registramos 101 espécies de peixes de variados grupos taxonômicos e funcionais, incluindo espécies reofílicas e de interesse à pesca. Pantanal flooded areas are important feeding, growth and spawn sites for fishes. Both natural and antropogenic causes are changing the vegetation on these areas. For instance, native grasses have being replaced by algodoais (Ipomoea carnea), cambarazais (Vochysia divergens) and exotic pastures (Brachiaria spp.). We studied the consequences of these landscape replacements over fishes in northern Pantanal flooded areas. We compared species richness, fish biomass and abundance in those four vegetation types using thirty 25 m2 quadrants. We registered 101 species of several taxonomic and ecological groups, including migratory ones of interest to fisheries.bitstream/item/56660/1/BP112-lancado.pd

Azimuthal Fourier decomposition for loss analysis of hollow-core tube lattice fibers, Part II: Tube thickness variation effects

The effect on confinement loss of thickness variations along the perimeter of the tubes composing the cladding of inhibited-coupling guiding Tube Lattice hollow-core fibers is investigated by using the Azimuthal Fourier Decomposition technique (developed in Part I) for the description of the cladding modal dynamics and their interaction with the fundamental core mode. The results show that the thickness inhomogeneity affects the confinement loss spectrum through confinement loss increase and frequency red- and blue-shift of the high- loss spectral regions. The magnitudes of the confinement loss increase and the high-loss region frequency shift strongly depend on the spatial distribution of the thickness inhomogeneity. The study provides insight into the loss mechanism of non-ideal tube lattice fibers, it allows to quantify the impact of such kind of structural deformations, identifying the route to make fibers more resilient to such fabrication imperfections, and highlighting once again the importance played in inhibited-coupling fibers by the interaction between core modes and the intricate set of cladding modes

The Brown-dwarf Atmosphere Monitoring (BAM) Project II: Multi-epoch monitoring of extremely cool brown dwarfs

With the discovery of Y dwarfs by the WISE mission, the population of field brown dwarfs now extends to objects with temperatures comparable to those of Solar System planets. To investigate the atmospheres of these newly identified brown dwarfs, we have conducted a pilot study monitoring an initial sample of three late T-dwarfs (T6.5, T8 and T8.5) and one Y-dwarf (Y0) for infrared photometric variability at multiple epochs. With J-band imaging, each target was observed for a period of 1.0h to 4.5h per epoch, which covers a significant fraction of the expected rotational period. These measurements represent the first photometric monitoring for these targets. For three of the four targets (2M1047, Ross 458C and WISE0458), multi-epoch monitoring was performed, with the time span between epochs ranging from a few hours to ~2 years. During the first epoch, the T8.5 target WISE0458 exhibited variations with a remarkable min-to-max amplitude of 13%, while the second epoch light curve taken ~2 years later did not note any variability to a 3% upper limit. With an effective temperature of ~600 K, WISE0458 is the coldest variable brown dwarf published to-date, and combined with its high and variable amplitude makes it a fascinating target for detailed follow-up. The three remaining targets showed no significant variations, with a photometric precision between 0.8% and 20.0%, depending on the target brightness. Combining the new results with previous multi-epoch observations of brown dwarfs with spectral types of T5 or later, the currently identified variables have locations on the colour-colour diagram better matched by theoretical models incorporating cloud opacities rather than cloud-free atmospheres. This preliminary result requires further study to determine if there is a definitive link between variability among late-T dwarfs and their location on the colour-colour diagram.Comment: 9 pages, 6 figures, 3 tables, accepted for publication in MNRA

Scaling Issues for the Experimental Characterization of Reactor Coolant System in Integral Test Facilities and Role of System Code as Extrapolation Tool

The phenomenological analyses and thermal hydraulic characterization of a nuclear reactor are the basis for its design and safety evaluation. In light of the impossibility and huge cost of performing meaningful experiments at full scale, scaled down experimental tests - Integral Effect Test (IET) and Separate Effect Test (SET) - are more feasible in developing “assessment database”. The data are useful in characterizing the prototype design and in the validation of computational tools for safety analysis. The analyses of system behaviors including component interactions in the Reactor Coolant System (RCS), the Containment System (PCV) and the RCS/PCV coupled system have been extensively investigated using IETs in the past decades. Though several scaling methods, e.g. Linear, Power/Volume, Three level scaling, H2TS..., have been developed and applied in the IET and SET design, a direct extrapolation of the data to the prototype, i.e. the scalability, is in general not possible due to unavoidable scaling distortions. The scaling distortions are related to many factors, mainly the complex geometry, multiple component interactions and two phase thermal hydraulic phenomena in steady state and transient condition of a nuclear reactor. The complex nature of scaling a nuclear reactor requires a large number of scaling parameters to be simultaneously fulfilled. In addition, physical construction and funding constraints demand that a scaling compromise is inevitable. Therefore a scaling approach, e.g. time preserved/not preserved, full height/reduced height, full pressure/reduced pressure, full power/reduced power…, has to be adopted in accordance with the objective of the IET or SET. Together with the scaling analysis, Best Estimate (BE) thermal hydraulic system code has been used for supporting experiment activity (design facilities, interpretation of results, etc) and for extrapolating results to full scale prototype conditions. Since the closure laws in the system code are mainly based on scaled test data, the extrapolation of code results remains a challenging and open issue. Starting from a brief analysis of the main characteristics of IETs and SETFs, the main objective of this paper is to analyze some IET scaling approaches used to the simulation of RCS responses which characterize the main scaling limits. The scaling approaches and their constraints in ROSA-III, FIST and PIPER-ONE facility will be used to analyze their impact to the experimental prediction in Small Break LOCA counterpart tests. The liquid level behavior in the core and the core cladding temperature analysis are discussed used as judging criteria for the facilities scaling-up limits

Diversification, concentration and renewability of the energy supply in the European Union

Energy security assessment quantifies the energy supply to a population and the likelihood, or risk, of an energy disruption or shortage and represents an important aspect of national security, economic stability and prosperity. The quantification of the state of energy supply is context-dependent and involves multiple perspectives: infrastructural, technological, environmental, market, social and geopolitical. Among all the different and relevant aspects involved, diversity and dependence of the energy fuel mix are two of the main energy security dimensions. The present paper investigates the diversification of the energy supply in Europe, by analysing import dependence, market concentration and renewable energy resource deployment in the European Union over the last decade. The analysis utilises a set of indicators aimed at measuring the fuel mix diversity, market concentration, geopolitical stability, renewable energy share and stochasticity - both at single country and at aggregated European levels. Results show a stable evolution of the diversity of the fuel mix and a relatively low market concentration of the period examined. However, the import dependency reduces the energy security by approximately 30% due to the high proportion of imports from a limited number of countries. Moreover, an increasing trend in renewable electricity production share is evident over the last decade, albeit with differences between member states, as a result of the decarbonisation policies implemented by the European Union

Avaliação de genótipos de soja submetidos ao encharcamento.

Levando-se em consideração a grande variedade de cultivares no mercado e também os impactos das mudanças climáticas sobre a produção agrícola, torna-se necessário a seleção dos genótipos de soja adaptados ao alagamento imediato dos solos e também aqueles que melhor se recuperam após este estresse. Assim, o objetivo deste trabalho foi avaliar o comportamento de genótipos de soja quando submetidos a período de encharcamento do solo. O ensaio foi conduzido na safra 2008/09 na Granja Quatro Irmãos (Município de Rio Grande), no delineamento de blocos ao acaso, com quatro repetições, sendo a parcela composta por quatro linhas com 5 m de comprimento e 0,50 m de espaçamento entre linhas, sendo descartadas as duas linhas externas e 50 cm na extremidade de cada linha. Os genótipos avaliados foram: BRS 255 RR,BMX Apolo RR e FUNDACEP 53 RR (ciclo precoce); BRS 244 RR, BRS 246 RR e BRS Taura RR (ciclo médio);BRS Pampa RR, CD 219 RR e FUNDACEP 59 RR (ciclo tardio). Dentre os genótipos de ciclo precoce o que apresentou a menor perda para rendimentos de grãos quando submetido ao encharcamento foi Fundacep 53 RR, dentre os de ciclo médio foi BRS 246 RR. Na avaliação dos genótipos de ciclo tardio observou-se que na média durante o encharcamento no reprodutivo eles foram mais produtivos que os genótipos de ciclo precoce e médio

Analysis of the OSU-MASLWR 001 and 002 tests by using the TRACE code

The Oregon State University (OSU) has constructed, under a U.S. Department of Energy grant, a scaled integral test facility to examine natural circulation phenomena characterizing the Multi-Application Small Light Water Reactor (MASLWR) design. The MASLWR is a small modular PWR relying on natural circulation during both steady-state and transient operation, which includes an integrated helical coil steam generator within the reactor pressure vessel. Testing has been conducted in order to assess the operation of the prototypical MASLWR under normal full pressure and full temperature conditions and to assess the passive safety systems performance. The experimental data produced are useful also for the assessment of the computational tools necessary for the operation, design and safety analysis of nuclear reactors. This report describes the assessment of TRACE code predictions, conducted under the NRC CAMP program, against the MASLWR tests OSU-MASLWR-001 and the OSU-MASLWR-002, respectively. This activity has been conducted in collaboration with the Italian National Agency for the New Technologies, Energy and Sustainable Economic Development (ENEA), the Department of Energy of the University of Palermo, the Gruppo di Ricerca Nucleare San Piero a Grado (GRNSPG) of University of Pisa, the Department of Nuclear Engineering and Radiation Health Physics at OSU and NuScale Power Inc. In particular the OSU-MASLWR-001 test, an inadvertent actuation of one submerged ADS valve, investigates the primary system to containment coupling under design basis accident conditions; the OSU-MASLWR-002 test, a natural circulation test, investigates the primary system flow rates and secondary side steam superheat for a variety of core power levels and feed water flow rates. The assessment against experimental data shows that the TRACE code predicts the main phenomena of interest of the selected tests reasonably well for most condition

Estrutura trófica da comunidade de peixes de riachos da porção oeste da bacia do Alto Paraná.

O conhecimento ecológico de peixes de riachos brasileiros ainda possui lacunas. Apesar dos muitos estudos ictiológicos na Bacia do Alto Rio Paraná, poucos foram conduzidos em córregos da região Centro-Oeste, uma das mais ameaçadas pela expansão agropecuária. Este estudo é resultado da compilação dos dados de amostras obtidas em riachos da porção Oeste da Bacia do Alto Rio Paraná. Nosso objetivo é analisar a dieta da ictiofauna e alocar as mais abundantes em guildas tróficas. Selecionamos 343 indivíduos de 44 espécies de peixes de 35 riachos nas sub-bacias dos rios Ivinhema, Pardo e Sucuriú, além de riachos que deságuam diretamente no rio Paraná. As 22 espécies mais abundantes foram classificadas em seis grupos tróficos: insetívoros bentônicos, onívoros generalistas, insetívoros, carnívoro com tendência à piscivoria, onívoros com tendência à herbivoria e iliófago-detritívoros. A classificação trófica de cada espécie na literatura foi revisada e discutida. Diferenças na composição da dieta e inclusão em guildas entre estudos foram frequentes, o que provavelmente se relaciona ao generalismo e a plasticidade trófica típicos de peixes de riachos. Nesse contexto, sugerimos que estudos de dieta em riachos tenham escalas espaciais, temporais e ontogenéticas amplas, e que a classificação de espécies em guildas a priori não é aconselhável.bitstream/item/79842/1/BP117.pd