2,374 research outputs found
Analysis of intermittency in submillimeter radio and hard x-ray data during the impulsive phase of a solar flare
We present an analysis of intermittent processes occurring during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and has so far only been analyzed for hard X-ray data. Since in a typical flare the same accelerated electron population is believed to produce both hard X-rays and gyrosynchrotron radiation, we compare the two time profiles by searching for intermittency signatures. For this, we define a cross-wavelet power spectrum, which is used to obtain the local intermittency measure, or LIMLIM. When greater than three, the square LIMLIM coefficients indicate a local intermittent process. The LIM2LIM2 coefficient distribution in time and scale helps to identify avalanche or cascade energy release processes. We find two different and well-separated intermittent behaviors in the submillimeter data: for scales greater than 20 s, a broad distribution during the rising and maximum phases of the emission seems to favor a cascade process; for scales below 1 s, short pulses centered on the peak time are representative of avalanches. When applying the same analysis to hard X-rays, we find that only the scales above 10 s produce a distribution related to a cascade energy fragmentation. Our results suggest that different acceleration mechanisms are responsible for tens of keV and MeV energy ranges of electrons
Treatment of landfill leachate: Removal of ammonia by struvite formation
This paper presents a study of ammoniacal nitrogen removal by chemical precipitation resulting in the formation of ammonium and magnesium phosphat (MgNH4PO4·6H2O), known as struvite, from the leachate in the Delta A landfill, located in the city of Campinas, São Paulo, Brazil. After the addition of a magnesium source (MgCl2·6H2O), and phosphorus (Na2HPO4·12H2O), ammoniacal nitrogen was precipitated as highly insoluble salt. The removal of ammoniacal nitrogen from the leachate exceeded 85% when the reaction was performed at an initial pH of 10.0. The highest efficiencies were achieved when the molar ratio between the ions involved in the reaction, i.e., Mg2+:PO43-:NH4+, was 1.2:1.0:1.0, respectively.Keywords: landfill, leachate, ammonia, nitrogen remova
Collapse of an ecological network in Ancient Egypt
The dynamics of ecosystem collapse are fundamental to determining how and why
biological communities change through time, as well as the potential effects of
extinctions on ecosystems. Here we integrate depictions of mammals from
Egyptian antiquity with direct lines of paleontological and archeological
evidence to infer local extinctions and community dynamics over a 6000-year
span. The unprecedented temporal resolution of this data set enables
examination of how the tandem effects of human population growth and climate
change can disrupt mammalian communities. We show that the extinctions of
mammals in Egypt were nonrandom, and that destabilizing changes in community
composition coincided with abrupt aridification events and the attendant
collapses of some complex societies. We also show that the roles of species in
a community can change over time, and that persistence is predicted by measures
of species sensitivity, a function of local dynamic stability. Our study is the
first high-resolution analysis of the ecological impacts of environmental
change on predator-prey networks over millennial timescales, and sheds light on
the historical events that have shaped modern animal communities
Vulnerabilidade das microrregiões do Estado de São Paulo à pandemia do novo coronavírus (SARS-CoV-2)
Neste relatório, associamos dados da rede de fluxos rodoviários e da demografia das microrregiões paulistas com os casos confirmados de COVID-19 atualizados em 04/04/2020 para gerar i nformações estratégicas sobre a propagação geográfica da pandemia de SARS-CoV-2 no Estado de São Paulo. Identificamos microrregiões que podem atuar como núcleos propagadores da epidemia ou que têm alta vulnerabilidade a receber pessoas i nfectadas. Desta forma, atualizamos a i dentificação das microrregiões mais vulneráveis à propagação geográfica da pandemia do novo coronavírus ( SARS-CoV-2) no estado
Interaction paths promote module integration and network-level robustness of spliceosome to cascading effects
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPThe functionality of distinct types of protein networks depends on the patterns of protein-protein interactions. A problem to solve is understanding the fragility of protein networks to predict system malfunctioning due to mutations and other errors. Spec8111CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2017/08406-7, 2017/06994-9We thank Ana Paula Assis, Pâmela C. Santana and Leandro Giacobelli for helpful comments. PRG was supported by CNPq and FAPESP (2017/08406-7). PPC was supported by FAPESP (2017/06994-9). MC was supported by a PMP/BS postdoctoral fellowship (UFPR/UNIVALI 4
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