336 research outputs found
Taxonomic revision and phylogeny of the sharpshooter genus Dasmeusa Melichar, 1926, with a scanning electron microscopy study of D. pauperata (Fabricius, 1803) (Hemiptera: Cicadellidae: Cicadellini)
The genus Dasmeusa is distributed in Northern and Northeastern Brazil and the Guianas. Until the present study, six species were recognized within Dasmeusa. The species of this genus are very similar in terms of color and external morphology, being distinguished mainly by the male terminalia. Here, we review and redescribe Dasmeusa and its species, describe four new species, and present the first phylogenetic analysis of the genus, including 40 morphological characters and 15 terminal taxa. Dasmeusa flavescens Metcalf and Erythrogonia bicolor Metcalf are considered junior synonyms of the type-species, Dasmeusa pauperata (Fabricius). Scanning electron microscopy was employed for a detailed study of the integument of the type-species, including sensilla, surface sculpturing, brochosomes, organ of Evans, and other structures. The phylogenetic analysis with equal weights resulted in nine most parsimonious trees. The implied weighting method resulted in two trees, both with the same ingroup topology as observed in one of the nine equal-weights trees. This preferred topology is as follows: ((D. basseti (D. mendica (D. rafaeli sp. nov., D. falcifera sp. nov.))) (D. isabellina (D. oriximina sp. nov. (D. pauperata (D. imperialis, D. dinizi sp. nov.))))). Dasmeusa was recovered as monophyletic in all trees, being supported by five apomorphic characters
Can a “Zero Land Use” Diet Maintain Milk Production of Dairy Cows?
Dairy cows can convert feeds unsuitable and unpalatable for humans into milk and play a key role in food security. Feed efficiency is usually calculated as the ratio between nutrients secreted in milk and nutrient intake, but this metric does not address concerns about human/livestock feed competition. This study aimed to evaluate whether cows fed a “zero land use” diet (diet that does not affect land used for production of human food), with or without rumen-protected amino acids, can maintain milk compared to a conventional lactation diet. Twelve second-lactation dairy cows were used in a 3×3 Latin square design experiment to evaluate 1) conventional total mixed ration (TMR) for lactating cows (CON), containing 25.7% byproduct feeds; 2) a TMR comprised of zero land use feedstuffs (ZLU); and 3) ZLU with top-dressed rumen-protected amino acids (ZLU-AA). Cows fed ZLU or ZLU-AA diets consumed less dry matter (P \u3c 0.01) and decreased (P \u3c 0.01) milk and energy-corrected milk yield of cows. Feed efficiency was similar between cows fed CON and ZLU but it was reduced (P \u3c 0.01) when cows were fed ZLU-AA. In a scenario reflecting current food system byproduct use, cows fed ZLU diets showed greater (P \u3c 0.01) human-edible metabolizable energy and protein recovery in milk than cows fed CON. Zero land use diets did not maintain milk production of late-lactation cows either with or without rumen-protected amino acids
Direct dark matter search by annual modulation in XMASS-I
A search for dark matter was conducted by looking for an annual modulation
signal due to the Earth's rotation around the Sun using XMASS, a single phase
liquid xenon detector. The data used for this analysis was 359.2 live days
times 832 kg of exposure accumulated between November 2013 and March 2015. When
we assume Weakly Interacting Massive Particle (WIMP) dark matter elastically
scattering on the target nuclei, the exclusion upper limit of the WIMP-nucleon
cross section 4.310cm at 8 GeV/c was obtained and we
exclude almost all the DAMA/LIBRA allowed region in the 6 to 16 GeV/c range
at 10cm. The result of a simple modulation analysis, without
assuming any specific dark matter model but including electron/ events,
showed a slight negative amplitude. The -values obtained with two
independent analyses are 0.014 and 0.068 for null hypothesis, respectively. we
obtained 90\% C.L. upper bounds that can be used to test various models. This
is the first extensive annual modulation search probing this region with an
exposure comparable to DAMA/LIBRA.Comment: 5 pages, 4 figure
Search for two-neutrino double electron capture on Xe with the XMASS-I detector
Double electron capture is a rare nuclear decay process in which two orbital
electrons are captured simultaneously in the same nucleus. Measurement of its
two-neutrino mode would provide a new reference for the calculation of nuclear
matrix elements whereas observation of its neutrinoless mode would demonstrate
lepton number violation. A search for two-neutrino double electron capture on
Xe is performed using 165.9 days of data collected with the XMASS-I
liquid xenon detector. No significant excess above background was observed and
we set a lower limit on the half-life as years at 90%
confidence level. The obtained limit has ruled out parts of some theoretical
expectations. We obtain a lower limit on the Xe two-neutrino double
electron capture half-life of years at 90% confidence
level as well.Comment: 6 pages, 3 figures, accepted for publication in Physics Letters
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