341 research outputs found
Crescimento De Cana-de-açúcar Sob Aplicação De Biofertilizante Da Bovinocultura E Ureia
Effluents from intensive cattle breeding and treated with anaerobic reactors are highly relevant for agricultural reuse. Current paper assesses the growth of sugarcane cultivars SP 803280 and RB 867515 for 220 days. Doses 0, 16, 48, 64, 80 and 96 kg ha-1 N were applied derived from biofertilizing sources produced by cattle-breeding waste water and urea. Experimental design comprised randomized blocks with 96 splits and four replications. The cultivars fertilized with biofertilizers caused growth similar to those fertilized with urea. Doses 64, 80 and 96 kg ha-1 had the best efficiency in growth. Since average height of 3 m was obtained for cultures at the end of the experiment, urea may be replaced by biofertilizers.9497398
Assessment of hydropyrolysis as a method for the quantification of black carbon using standard reference materials
A wide selection of thermal, chemical and optical methods have been proposed for the quantification of black carbon (BC) in environmental matrices, and the results to date differ markedly depending upon the method used. A new approach is hydropyrolysis (hypy), where pyrolysis assisted by high hydrogen pressures (150 bar) facilitates the complete reductive removal of labile organic matter, so isolating a highly stable portion of the BC continuum (defined as BChypy). Here, the potential of hypy for the isolation and quantification of BC is evaluated using the 12 reference materials from the International BC Ring Trial, comprising BC-rich samples, BC-containing environmental matrices and BC-free potentially interfering materials. By varying the hypy operating conditions, it is demonstrated that lignocellulosic, humic and other labile organic carbon material (defined as non-BChypy) is fully removed by 550 °C, with hydrogasification of the remaining BChypy not commencing until over 575 °C. The resulting plateau in sample mass and carbon loss is apparent in all of the environmental samples, facilitating BC quantification in a wide range of materials. The BChypy contents for all 12 ring trial samples fall within the range reported in the BC inter-comparison study, and systematic differences with other methods are rationalised.
All methods for BC isolation, including hypy are limited by the fact that BC cannot be distinguished from extremely thermally mature organic matter; for example in high rank coals. However, the data reported here indicates that BChypy has an atomic H/C ratio of less than 0.5 and therefore comprises a chemically well-defined polyaromatic structure in terms of the average size of peri-condensed aromatic clusters of >7 rings (24 carbon atoms), that is consistent across different sample matrices. This, together with the sound underlying rationale for the reductive removal of labile organic matter, makes hypy an ideal approach for matrix independent BC quantification. The hypy results are extremely reproducible, with BChypy determinations from triplicate analyses typically within ±2% across all samples, limited mainly by the precision of the elemental analyser
Gravitational collapse of a Hagedorn fluid in Vaidya geometry
The gravitational collapse of a high-density null charged matter fluid,
satisfying the Hagedorn equation of state, is considered in the framework of
the Vaidya geometry. The general solution of the gravitational field equations
can be obtained in an exact parametric form. The conditions for the formation
of a naked singularity, as a result of the collapse of the compact object, are
also investigated. For an appropriate choice of the arbitrary integration
functions the null radial outgoing geodesic, originating from the shell
focussing central singularity, admits one or more positive roots. Hence a
collapsing Hagedorn fluid could end either as a black hole, or as a naked
singularity. A possible astrophysical application of the model, to describe the
energy source of gamma-ray bursts, is also considered.Comment: 14 pages, 2 figures, to appear in Phys. Rev.
The development of gaze following in monolingual and bilingual infants: A multi‐laboratory study
Copepod diversity along the Congo River Basin: a first approach
peer reviewedThe free-living copepods of the Congo River Basin in Africa, the second largest in the world just after the Amazonas River Basin, are still insufficiently known because of problematic accessibility and complex logistics related to sampling. We analyzed samples from 82 sites obtained during expeditions in 2010 and 2013. The Congo River main channel and its main mouth tributaries (1700km; between Kisangani and Kinshasa), and the Kasai River and its main mouth tributaries (600km) were visited. A Schindler-Patallas trap was used in the open waters, with five samplings at each site. Twenty-five taxa were found, with dominance of immature forms (nauplii and copepodites). We recognized three undescribed species of Cyclopoida. The most speciose genera were: Microcyclops (five species), Mesocyclops, , and (three species each). The most frequent species were: Microcyclops varicans (27,6% of the samples) and Cryptocyclops sp. (10,6%). Few presumably cosmopolitan species were found, like pocyclops prasinus, , and Microcyclops varicans. Few diaptomid calanoids were found. Rarefaction and extrapolation curves revealed that the diversity found is about half that estimated considering just the open water species here studied. Spatially, the highest species richness was found in the main channel of the Congo River (23) compared to Kasai (20) and other tributaries (14, 9 from the Congo tributaries, 6 from the Kasai). The abundance of adult individuals was low, with an average of 2,36 individuals per sample when considering all water bodies. A distance-based redundancy analysis based on abundance and Bray Curtis dissimilarity index revealed two large groups of copepod species in the sites of the Congo main channel, plus two minor groups with mixed sites among Congo and Kasai main channels, and tributaries of both rivers, the latter being represented by small groups correlated with nitrogen forms, total phosphorus, and oxygen concentrations. Concerning the two large Congo´s channel groups of species, one was associated with water transparency, chlorophyll, and phytoplankton dominated by Dinophyceae, Chlorophyceae, Cryptophyceae, and diatoms. The other was correlated with conductivity, chlorophyll-a and Cyanophyceae. Kasai main channel sampling sites were dispersed among the four groups resulting from our analysis. Our results indicate that the copepod species in the area are separated into two large groups associated with black and white waters, with low and high primary productivity, respectively. The results showed a high copepod diversity along the Congo Basin as expected for large tropical rivers, and a low abundance for the adult copepods, as in other lotic environments. More species are expected to be discovered in this basin with the continuation of this investigation
Neotropical and Afrotropical freshwater copepods: recent advances
peer reviewedI present new perspectives and advances on the knowledge of free-living copepods in large tropical river basins. Currently, the greatest copepod diversity is known from the Palearctic region, with a surface about twice or thrice that of the Neotropical and Afrotropical areas, respectively. Interestingly, biological diversity estimators suggest a much higher and largely unexplored diversity in the two latter regions, potentially reaching or exceeding that of the Palearctic. I show trends for both regions, focused on Brazil and Congo Basins. Brazil comprises almost 40 % of the Neotropical region surface, including four rivers among the 20 largest in the world. Based on the literature review, there are 190 free-living copepod species in the country. Among the 12 hydrographic regions in Brazil, the richest are the Amazon and the Paraná basins, with the largest surface. Taxonomical studies on Brazilian copepods were predominant until 1979, yet, between 1980 and 1989 ecologically-oriented works were developed and became a main trend after 1990, representing over 80% of copepod studies after 2000. Molecular diversity and functional ecology are still poorly studied. Ecological studies with molecular-based diversity parameters, functional attributes or comprehensive spatialtemporal data of copepod species behavior and environmental variables have been used to detect effects of environmental changes both at population and community levels. Cyclopoid copepods composition and abundance changes according to the trophic level, but calanoids appear to be influenced by conductivity. The presence of cyanobacteria and phytoplankton of lower nutritional value can cause a bottom-up effect on the copepods, resulting in low functional diversity and increase of functional uniformity. Large filtering copepods can be replaced by small cyclopoids at increasing eutrophicated conditions. The Afrotropical region comprises four of the largest rivers worldwide. The most studied environments have been the great lakes of the rift valley (e.g. Tanganyika, Victoria, Kivu), the Nile River, and several places in South Africa. The Congo River, the second largest in the world, is almost entirely unknown in terms of copepod composition and ecology. Herein, I show initial data revealing the lack of knowledge of the l extant Congo copepod diversity, with a high potential for new species. Two expeditions made in 2013 and 2015 along the Congo and the Kasai River revealed 15 copepod species, but rarefaction and extrapolation diversity curves suggest the presence of at least double of this number. There are four large groups of copepods species in the Congo Basin, being the two largest separated by differences in primary productivity (white waters rivers) or microbial food web (black waters rivers). Copepods within the main channel of the Congo River seem to be less dissimilar than tributaries, thus reinforcing the effect of upstream basins, a trend observed in other large tropical river basins. Each large river has different copepod species especially for diaptomid calanoids and also for some Cyclopoida species, but just the last have shared species between Afrotropical and Neotropical regions. The river continuum and the flood pulse concepts were applied in these large tropical rivers, but both were disrupted by reservoirs. The large rivers of these tropical regions appear seem proportionally equal in copepod diversity according to this surface, and linked to their historical biogeography
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
Anurofauna (Amphibia, Anura) em um remanescente de Floresta Ombrófila Mista no Estado de Santa Catarina, Sul do Brasil
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
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