Historical biogeography of the neotropical Diaptomidae (Crustacea:Copepoda)

Introduction: Diaptomid copepods are prevalent throughout continental waters of the Neotropics, yet little is\ud known about their biogeography. In this study we investigate the main biogeographical patterns among the\ud neotropical freshwater diaptomid copepods using Parsimony Analysis of Endemicity (PAE) based on species records\ud within ecoregions. In addition, we assess potential environmental correlates and limits for species richness.\ud Results: PAE was efficient in identifying general areas of endemism. Moreover, only ecoregion area showed a\ud significant correlation with diaptomid species richness, although climatic factors were shown to provide possible\ud upper limits to the species richness in a given ecoregion.\ud Conclusion: The main patterns of endemism in neotropical freshwater diaptomid copepods are highly congruent\ud with other freshwater taxa, suggesting a strong historical signal in determining the distribution of the family in the\ud Neotropics.We would like to thank to Professor Edinaldo Nelson dos Santos Silva (INPA, Brazil) for useful insight during this study. We also thank FAPESP (process 2008/02015-7, 2009/00014-6, 2011/18358-3) for financial support to GPN; and CNPq for financial support to DP (process 141702/2006-0) and MRP (process 304897/2012-4)

Estimating cyclopoid copepod species richness and geographical distribution (Crustacea) across a large hydrographical basin: comparing between samples from water column (plankton) and macrophyte stands

Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the La Plata River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and macrophytes was supported by nonmetric multidimensional analysis. There was no distinct pattern of endemicity within the basin, and double sampling contributes to this result. This lack of sub-regional faunal differentiation is in accordance with other studies that have shown that cyclopoids generally have wide geographical distribution in the Neotropics and that some species there are cosmopolitan. This contrasts with other freshwater copepods such as Calanoida and some Harpacticoida. We conclude that sampling plankton and macrophytes together provided a more accurate estimate of the richness and geographical distribution of these organisms than sampling in either one of those zones alone

Microwave-assisted preparation of a new esterification catalyst from wasted flint kaolin

AbstractAmazon flint kaolin, considered useless from an economic and industrial point of view, was calcined at 850 and 950°C to obtain metakaolin samples. These samples were subsequently treated with sulfuric acid (4M) by assisted heating with microwave radiation. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy and N2 physisorption; the surface acidity was determined by titration with 0.2M KOH. The materials obtained were used as catalysts in the esterification of oleic acid with methanol. Metakaolin that was calcined at 850°C and activated at 400W for 15min presented a surface area of 187m2g−1, yielding acidic sites with a concentration of 4.32mmolg−1 and a conversion of 96.5% (115°C, 40min, molar ratio of oleic acid: methanol 1:60). In addition to a lower preparation time, the flint metakaolin activated by microwave radiation gave a catalytic performance equivalent or superior to the one prepared by reflux, as well as it showed considerably reduced reaction time and temperature

Dielectron and heavy-quark production in inelastic and high-multiplicity proton–proton collisions at √s = 13 TeV

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (pT) at midrapidity (|ye| < 0.8) in proton–proton (pp) collisions at a centre-of-mass energy of √s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at √s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: dσcc¯/dy|y=0 = 974 ± 138 (stat.) ± 140 (syst.) ± 214(BR) μb and dσbb¯ /dy|y=0 = 79 ± 14 (stat.) ± 11 (syst.) ± 5(BR) μb using PYTHIA simulations and dσcc¯/dy|y=0 = 1417 ± 184 (stat.) ± 204 (syst.) ± 312(BR) μb and dσbb¯ /dy|y=0 = 48 ± 14 (stat.) ± 7 (syst.) ± 3(BR) μb for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various pT intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of pT. Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations