271 research outputs found
La manteca de karité
A bibliographical review of the extraction, composition properties and applications of shea butter is made.Se hace una revisión bibliográfica sobre la extracción, composición, propiedades y aplicaciones de la manteca de karité
Os cariótipos de Trinomys moojeni (Pessôa, Oliveira & Reis, 1992) e de Trinomys setosus elegans (Lund, 1841) (Rodentia, Echimyidae) de Minas Gerais, leste do Brasil
Two new karyotypes of species in the genus Trinomys are described from specimens collected recently in Morro do Pilar and Santa Bárbara, Minas Gerais State (MG), Brazil. Trinomys moojeni from Morro do Pilar had 2n=56 and FN=106 and T. setosus elegans from Santa Bárbara had 2n=56 and FN=104. Besides the differences in FN, different morphologies in the sex chromosomes also had been detected. These results at chromosomal level corroborate findings from the mitochondrial genome that suggest that T. s. elegans belongs to a clade composed by T. s. setosus and T. s. denigratus. The chromosomal data corroborated the inclusion of T. moojeni in this clade, as previously suggested on the basis of cranial morphology evidence.Dois novos cariótipos são descritos para espécies do gênero Trinomys com base em coletas recentes nos municípios de Morro do Pilar e Santa Bárbara no Estado de Minas Gerais (MG). Trinomys moojeni de Morro do Pilar apresentou o cariótipo com número diplóide (2n) igual a 56 e número fundamental (NF) igual a 106 e T. setosus elegans de Santa Bárbara apresentou 2n=56 e NF=104. Além da diferença nos valores de NF, diferenças na morfologia cromossômica do par sexual também foram detectadas. Os resultados no nível cromossômico corroboram aqueles encontrados com base no genoma mitocondrial, que evidenciou que T. s. elegans pertence a um clado composto por T. setosus setosus e T. s. denigratus. Os dados cromossômicos corroboraram a inclusão de T. moojeni neste clado, como previamente sugerido com base em evidências da morfologia craniana
Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests
A prototype for a sampling calorimeter made out of cerium fluoride crystals
interleaved with tungsten plates, and read out by wavelength-shifting fibres,
has been exposed to beams of electrons with energies between 20 and 150 GeV,
produced by the CERN Super Proton Synchrotron accelerator complex. The
performance of the prototype is presented and compared to that of a Geant4
simulation of the apparatus. Particular emphasis is given to the response
uniformity across the channel front face, and to the prototype's energy
resolution.Comment: 6 pages, 6 figures, Submitted to NIM
On the fraction of dark matter in charged massive particles (CHAMPs)
From various cosmological, astrophysical and terrestrial requirements, we
derive conservative upper bounds on the present-day fraction of the mass of the
Galactic dark matter (DM) halo in charged massive particles (CHAMPs). If dark
matter particles are neutral but decay lately into CHAMPs, the lack of
detection of heavy hydrogen in sea water and the vertical pressure equilibrium
in the Galactic disc turn out to put the most stringent bounds. Adopting very
conservative assumptions about the recoiling velocity of CHAMPs in the decay
and on the decay energy deposited in baryonic gas, we find that the lifetime
for decaying neutral DM must be > (0.9-3.4)x 10^3 Gyr. Even assuming the
gyroradii of CHAMPs in the Galactic magnetic field are too small for halo
CHAMPs to reach Earth, the present-day fraction of the mass of the Galactic
halo in CHAMPs should be < (0.4-1.4)x 10^{-2}. We show that redistributing the
DM through the coupling between CHAMPs and the ubiquitous magnetic fields
cannot be a solution to the cuspy halo problem in dwarf galaxies.Comment: 21 pages, 2 figures. To appear in JCA
Crossover in the nature of the metallic phases in the perovskite-type RNiO_3
We have measured the photoemission spectra of NdSmNiO,
where the metal-insulator transition and the N\'{e}el ordering occur at the
same temperature for and the metal-insulator transition
temperature () is higher than the N\'{e}el temperature for . For , the spectral intensity at the Fermi level is high in the
metallic phase above and gradually decreases with cooling in the
insulating phase below while for it shows a pseudogap-like
behavior above and further diminishes below . The results
clearly establish that there is a sharp change in the nature of the electronic
correlations in the middle () of the metallic phase of the
NiO system.Comment: 4 pages, 4 figure, submitted to Phys. Rev.
Anomalous high-temperature superconductivity in YH
Pressure-stabilized hydrides are a new rapidly growing class of
high-temperature superconductors which is believed to be described within the
conventional phonon-mediated mechanism of coupling. Here we report the
synthesis of yttrium hexahydride Im3m-YH that demonstrates the
superconducting transition with T = 224 K at 166 GPa, much lower than the
theoretically predicted (>270 K). The measured upper critical magnetic field
B(0) of YH was found to be 116-158 T, which is 2-2.5 times larger
than the calculated value. A pronounced shift of T in yttrium deuteride
YD with the isotope coefficient 0.4 supports the phonon-assisted
superconductivity. Current-voltage measurements showed that the critical
current I and its density J may exceed 1.75 A and 3500 A/mm at 0 K,
respectively, which is comparable with the parameters of commercial
superconductors, such as NbTi and YBCO. The superconducting density functional
theory (SCDFT) and anharmonic calculations suggest unusually large impact of
the Coulomb repulsion in this compound. The results indicate notable departures
of the superconducting properties of the discovered YH from the
conventional Migdal-Eliashberg and Bardeen-Cooper-Schrieffer theories.Comment: arXiv admin note: text overlap with arXiv:1902.1020
Trajectories of alcohol consumption during life and the risk of developing breast cancer
Background: Whether there are lifetime points of greater sensitivity to the deleterious effects of alcohol intake on the breasts remains inconclusive. Objective: To compare the influence of distinctive trajectories of alcohol consumption throughout a woman’s life on development of breast cancer (BC). Methods: 1278 confirmed invasive BC cases and matched (by age and residence) controls from the Epi-GEICAM study (Spain) were used. The novel group-based trajectory modelling was used to identify different alcohol consumption trajectories throughout women’s lifetime. Results: Four alcohol trajectories were identified. The first comprised women (45%) with low alcohol consumption (<5 g/day) throughout their life. The second included those (33%) who gradually moved from a low alcohol consumption in adolescence to a moderate in adulthood (5 to <15 g/day), never having a high consumption; and oppositely, women in the third trajectory (16%) moved from moderate consumption in adolescence, to a lower consumption in adulthood. Women in the fourth (6%) moved from a moderate alcohol consumption in adolescence to the highest consumption in adulthood (=15 g/day), never having a low alcohol consumption. Comparing with the first trajectory, the fourth doubled BC risk (OR 2.19; 95% CI 1.27, 3.77), followed by the third (OR 1.44; 0.96, 2.16) and ultimately by the second trajectory (OR 1.17; 0.86, 1.58). The magnitude of BC risk was greater in postmenopausal women, especially in those with underweight or normal weight. When alcohol consumption was independently examined at each life stage, =15 g/day of alcohol consumption in adolescence was strongly associated with BC risk followed by consumption in adulthood. Conclusions: The greater the alcohol consumption accumulated throughout life, the greater the risk of BC, especially in postmenopausal women. Alcohol consumption during adolescence may particularly influence BC risk. © 2021, The Author(s)
Overeating, caloric restriction and breast cancer risk by pathologic subtype: the EPIGEICAM study
This study analyzes the association of excessive energy intake and caloric restriction with breast
cancer (BC) risk taking into account the individual energy needs of Spanish women. We conducted
a multicenter matched case-control study where 973 pairs completed lifestyle and food frequency
questionnaires. Expected caloric intake was predicted from a linear regression model in controls,
including calories consumed as dependent variable, basal metabolic rate as an offset and physical
activity as explanatory. Overeating and caloric restriction were defined taking into account the 99%
confidence interval of the predicted value. The association with BC risk, overall and by pathologic
subtype, was evaluated using conditional and multinomial logistic regression models. While
premenopausal women that consumed few calories (>20% below predicted) had lower BC risk
(OR = 0.36; 95% CI = 0.21–0.63), postmenopausal women with an excessive intake (≥40% above
predicted) showed an increased risk (OR = 2.81; 95% CI = 1.65–4.79). For every 20% increase in relative
(observed/predicted) caloric intake the risk of hormone receptor positive (p-trend < 0.001) and HER2+
(p-trend = 0.015) tumours increased 13%, being this figure 7% for triple negative tumours. While high
energy intake increases BC risk, caloric restriction could be protective. Moderate caloric restriction, in
combination with regular physical activity, could be a good strategy for BC prevention
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