New Analyses of Double-Bang Events in the Atmosphere

We use CORSIKA+Herwig simulation code to produce ultra-high energy neutrino interactions in the atmosphere. Our aim is to reproduce extensive air showers originated by extragalactic tau-neutrinos. For charged current tau-neutrino interactions in the atmosphere, beside the air shower originated from the neutrino interaction, it is expected that a tau is created and may decay before reaching the ground. That phenomenon makes possible the generation of two related extensive air showers, the so called Double-Bang event. We make an analysis of the main characteristics of Double-Bang events in the atmosphere for mean values of the parameters involved in such phenomenon, like the inelasticity and tau decay length. We discuss what may happen for the ``out of the average'' cases and conclude that it may be possible to observe this kind of event in ultra-high energy cosmic ray observatories such as Pierre Auger or Telescope Array.Comment: 17 pages, 5 figures, final version to appear in BJ

Progress in Remote Sensing of Photosynthetic Activity over the Amazon Basin

Although quantifying the massive exchange of carbon that takes place over the Amazon Basin remains a challenge, progress is being made as the remote sensing community moves from using traditional, reflectance-based vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), to the more functional Photochemical Reflectance Index (PRI). This new index, together with satellite-derived estimates of canopy light interception and Sun-Induced Fluorescence (SIF), provide improved estimates of Gross Primary Production (GPP). This paper traces the development of these new approaches, compares the results of their analyses from multiple years of data acquired across the Amazon Basin and suggests further improvements in instrument design, data acquisition and processing. We demonstrated that our estimates of PRI are in generally good agreement with eddy-flux tower measurements of photosynthetic light use efficiency (epsilon) at four sites in the Amazon Basin: r(exp 2) values ranged from 0.37 to 0.51 for northern flux sites and to 0.78for southern flux sites. This is a significant advance over previous approaches seeking to establish a link between global-scale photosynthetic activity and remotely-sensed data. When combined with measurements of Sun-Induced Fluorescence (SIF), PRI provides realistic estimates of seasonal variation in photosynthesis over the Amazon that relate well to the wet and dry seasons. We anticipate that our findings will steer the development of improved approaches to estimate photosynthetic activity over the tropics

Transição em infraestruturas urbanas de controle pluvial: uma estratégia paisagística de adaptação às mudanças climáticas

Projeções em modelos climáticos globais quanto às emissões de gases de efeito estufa apontam um aumento na intensidade e frequência dos eventos extremos de chuva, que, associado ao crescimento urbano e à expansão das superfícies impermeáveis, deverá gerar impactos sem precedentes sobre a infraestrutura de drenagem. Diante desse cenário, as cidades têm a oportunidade de realizar uma transição infraestrutural ao adotar técnicas de Melhores Práticas de Manejo (MPM) das águas de chuva como solução mais sustentável, resiliente e integrada à paisagem urbana. Este estudo apresenta uma comparação qualiquantitativa entre reservatórios de detenção e MPM dos escoamentos como estratégias de controle pluvial. Considerando uma microbacia urbana na Região Metropolitana de São Paulo (RMSP), onde foram instalados dois reservatórios com volume de detenção total de 19.200 m3, distribuíram-se elementos de biorretenção e passeios porosos nas vias públicas localizadas na área de contribuição da bacia. O volume de retenção das técnicas propostas como tratamento dos espaços abertos públicos corresponde a 42% da capacidade de detenção dos reservatórios. Confirma-se, então, a viabilidade das MPM como alternativas para adaptação das cidades às mudanças climáticas, desde que levadas em conta as especificidades ambientais e paisagísticas locais no desenho desses elementos como forma de garantir a sua eficiência

Best management practices performance's analysis for the constitution of greenways in Fortaleza - CE

Aguanambi Avenue is in the city of Fortaleza, CE, and it is susceptible to flooding on rainy season. Green infrastructure is an important alternative to complement conventional infrastructure and consolidate urban resilience. With the main goal to propose the greenway’s implementation in Fortaleza’s road system, this research has developed a method to analyze the performance of Best Management Practices in mobility corridors. The proposal has distributed management techniques according to the road hierarchy established by the Land Use and Occupancy Law. The precipitation volume admitted is 65.2mm / h, with 10-year return time. The bioswales had better performance in express and arterial streets, with greater size; the rain gardens and flowerbeds responded better in collectors and local roads, considered of smaller size.A Avenida Aguanambi, situada na cidade de Fortaleza, CE, é conhecida pela suscetibilidade a alagamentos em períodos chuvosos. A infraestrutura verde é uma importante alternativa para complementar a convencional e consolidar a resiliência urbana nas vias. Com o objetivo principal de propor a implantação de corredores verdes no sistema viário de Fortaleza, CE, foi desenvolvido um método de análise do desempenho das melhores práticas de manejo em corredores de mobilidade. As técnicas de manejo foram distribuídas com base na hierarquia viária estabelecida pela Lei de Parcelamento, Uso e Ocupação do Solo. A precipitação admitida para a cidade foi de 65,2mm/h com tempo de retorno de dez anos. As biovaletas apresentaram melhor desempenho em vias expressas e arteriais, de maior porte; os jardins de chuva e canteiros pluviais responderam melhor em vias coletoras e locais, consideradas de menor porte

Confusing the extragalactic neutrino flux limit with a neutrino propagation limit

We study the possible suppression of the extragalactic neutrino flux due to a nonstandard interaction during its propagation. In particular, we study neutrino interaction with an ultra-light scalar field dark matter. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a new mechanism to reduce the ultra-high energy neutrino flux. We study both the cases of non-self-conjugate as well as self-conjugate dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms for the reduction of the neutrino flux.Comment: 15 pages, 4 figures. Important changes implemented. Abstract modified. Conclusions remain. To be published in JCA

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO