1,829 research outputs found
How to distinguish between a block cipher and a random permutation by lowering the input entropy
Efeitos da irrigação e de níveis de nitrogênio em aspectos qualitativos e nutricionais da figueira (Ficus carica L.)
In order to evaluate qualitative and nutritional aspects of fig-trees with respect to six irrigation and six nitrogen levels, at Ilha Solteira, SP, Brazil, an experiment was carried out in randomized blocks, with subdivided plots, and four replications. Results showed that in four dates during harvest, only the first analysis (January 2, 1991) showed influence of nitrogen fertilization on fruit soluble solids (brix). There was no significant effect of treatments on pulp/peel relation for the four harvestings. In relation to leaf macronutrient concentration at flowering, water supply influenced N, P and Ca concentrations, and nitrogen influenced only Ca concentration. For an average of 10 t.ha-1 of mature fruit and 1.3 t.ha-1 of immature fruit production, there was a nutrient export of about 65 kg.ha-1 of N; 10 kg.ha-1 of P2O5; 44 kg.ha-1 of K2O; 35 kg.ha-1 of Ca and 9 kg.ha-1 of Mg.Para avaliar aspectos qualitativos e nutricionais da figueira em relação a seis níveis de irrigação e de nitrogênio, desenvolveu-se um experimento em blocos ao acaso, com parcelas subdivididas e com quatro repetições, em Ilha Solteira,SP. Os resultados mostraram que em quatro datas de colheita, apenas a primeira análise (2 de janeiro de 91) mostrou influência da fertilização nitrogenada sobre os sólidos solúveis (brix) dos frutos. Não houve efeito significativo dos tratamentos sobre a relação polpa/casca, nas quatro colheitas. Com relação à concentração de macronutrientes nas folhas na época de florescimento, o suprimento de água influenciou as concentrações de N, P e Ca e a aplicação de nitrogênio influenciou apenas a concentração de Ca. Para uma produção média de 10 t.ha-1 de frutos maduros e de 1,3 t.ha-1 de frutos verdes, observou-se uma exportação de aproximadamente 65 kg.ha-1 de N; 10 kg.ha-1 de P2O5 ; 44 kg.ha-1 de K2O; 35 kg.ha-1 de Ca e 9 kg.ha-1 de Mg
Milk production of lacaune sheep with different degrees of crossing with manchega sheep in a commercial flock in Spain
The objective of the present study was to evaluate the effect of the grade of crossbreeding (Lacaune x Manchega) and environmental factors on milk production in a commercial flock in Spain. A total of 5769 milk production records of sheep with different degrees of purity of the Lacaune breed crossed with Manchega were used as follows: 100% Lacaune (n = 2960), 7/8 Lacaune (n = 502), 13/16 Lacaune (n = 306), 3/4 (n = 1288), 5/8 Lacaune (n = 441) and 1/2 Lacaune: Manchega (n = 272). Additional available information included the number of parity (1 to 8), litter size (single or multiple), and the season of the year of lambing (spring, summer, autumn and winter). A mixed model was used to evaluate the level of crossbreeding and environmental factors on milk production. The 100% Lacaune sheep presented the highest milk production with respect to the F1 Lacaune x Manchega sheep (p < 0.01), showing that as the degree of gene absorption increases with the Manchega breed, it presents lower milk yield. The 100%, 13/16, and 3/4 Lacaune genotypes had the highest milk yields with respect to the 1/2 Lacaune/Manchega breed (p < 0.001). The Lacaune registered on average 181.1 L in a period adjusted to 160 days of lactation (1.13 L/ day). Likewise, the parity number, litter size, and season of lambing effects showed significant differences (p < 0.01). It was concluded that 13/16 and 3/4 Lacaune/Manchega ewes presented the highest milk yields with respect to the other crosses
Computerized adaptive test and decision trees: A unifying approach
In the last few years, several articles have proposed decision trees (DTs) as an alternative to computerized adapted tests (CATs). These works have focused on showing the differences between the two methods with the aim of identifying the advantages of each of them and thus determining when it is preferable to use one method or another. In this article, Tree-CAT, a new technique for building CATs is presented. Unlike the existing work, Tree-CAT exploits the similarities between CATs and DTs. This technique allows the creation of CATs that minimise the mean square error in the estimation of the examinee’s ability level, and controls the item’s exposure rate. The decision tree is sequentially built by means of an innovative algorithmic procedure that selects the items associated with each of the tree branches by solving a linear program. In addition, our work presents further advantages over alternative item selection techniques with exposure control, such as instant item selection or simultaneous administration of the test to an unlimited number of participants. These advantages allow accurate on-line CATs to be implemented even when the item selection method is computationally costly
Stellar contents and Star formation in the young cluster Stock 18
We have carried out deep (V21 mag) \ubvri photometric study of the star
cluster Stock 18. These along with archival Infrared data have been used to
derive the basic cluster parameters and also to study the star formation
processes in and around the cluster region. The distance to the cluster is
derived as 2.80.2 kpc while its age is estimated as Myr.
Present study indicates that interstellar reddening is normal in the direction
of the cluster. The mass function slope is found to be -1.370.27 for the
mass range 111.9. There is no evidence found for the effect of
mass segregation in main-sequence stars of the cluster. A young stellar
population with age between 1-2 Myr have been found in and around the cluster
region. The presence of IRAS and AKARI sources with MSX intensity map also show
the youth of the Sh2-170 region.Comment: 25 pages, 11 figures, 3 tables (Accepted for publication in New
Astronomy
Computing gravitational waves from slightly nonspherical stellar collapse to black hole: Odd-parity perturbation
Nonspherical stellar collapse to a black hole is one of the most promising
gravitational wave sources for gravitational wave detectors. We numerically
study gravitational waves from a slightly nonspherical stellar collapse to a
black hole in linearized Einstein theory. We adopt a spherically collapsing
star as the zeroth-order solution and gravitational waves are computed using
perturbation theory on the spherical background. In this paper we focus on the
perturbation of odd-parity modes. Using the polytropic equations of state with
polytropic indices and 3, we qualitatively study gravitational waves
emitted during the collapse of neutron stars and supermassive stars to black
holes from a marginally stable equilibrium configuration. Since the matter
perturbation profiles can be chosen arbitrarily, we provide a few types for
them. For , the gravitational waveforms are mainly characterized by a
black hole quasinormal mode ringing, irrespective of perturbation profiles
given initially. However, for , the waveforms depend strongly on the
initial perturbation profiles. In other words, the gravitational waveforms
strongly depend on the stellar configuration and, in turn, on the ad hoc choice
of the functional form of the perturbation in the case of supermassive stars.Comment: 31 pages, accepted for publication in Phys. Rev. D, typos and minor
errors correcte
Cosmological expansion and local systems: a Lema\^{i}tre-Tolman-Bondi model
We propose a Lema\^{i}tre-Tolman-Bondi system mimicking a two-body system to
address the problem of the cosmological expansion versus local dynamics. This
system is strongly bound but participates in the cosmic expansion and is
exactly comoving with the cosmic substratum
Identification and validation of common molecular targets of hydroxytyrosol
Hydroxytyrosol (HT) is involved in healthful activities and is beneficial to lipid metabolism. Many investigations focused on finding tissue-specific targets of HT through the use of different omics approaches such as transcriptomics and proteomics. However, it is not clear which (if any) of the potential molecular targets of HT reported in different studies are concurrently affected in various tissues. Following the bioinformatic analyses of publicly available data from a selection of in vivo studies involving HT-supplementation, we selected differentially expressed lipid metabolism-related genes and proteins common to more than one study, for validation in rodent liver samples from the entire selection. Four miRNAs (miR-802-5p, miR-423-3p, miR-30a-5p, and miR-146b-5p) responded to HT supplementation. Of note, miR-802-5p was commonly regulated in the liver and intestine. Our premise was that, in an organ crucial for lipid metabolism such as the liver, consistent modulation should be found for a specific target of HT even if different doses and duration of HT supplementation were used in vivo. Even though our results show inconsistency regarding differentially expressed lipid metabolism-related genes and proteins across studies, we found Fgf21 and Rora as potential novel targets of HT. Omics approaches should be fine-tuned to better exploit the available databases
Effect of chronic intermittent hypoxia on triglyceride uptake in different tissues
Chronic intermittent hypoxia (CIH) inhibits plasma lipoprotein clearance and adipose lipoprotein lipase (LPL) activity in association with upregulation of an LPL inhibitor angiopoietin-like protein 4 (Angptl4). We hypothesize that CIH inhibits triglyceride (TG) uptake via Angptl4 and that an anti-Angptl4-neutralizing antibody would abolish the effects of CIH. Male C57BL/6J mice were exposed to four weeks of CIH or intermittent air (IA) while treated with Ab (30 mg/kg ip once a week). TG clearance was assessed by [H 3 ]triolein administration retroorbitally. CIH delayed TG clearance and suppressed TG uptake and LPL activity in all white adipose tissue depots, brown adipose tissue, and lungs, whereas heart, liver, and spleen were not affected. CD146+ CD11b α pulmonary microvascular endothelial cells were responsible for TG uptake in the lungs and its inhibition by CIH. Antibody to Angptl4 decreased plasma TG levels and increased TG clearance and uptake into adipose tissue and lungs in both control and CIH mice to a similar extent, but did not reverse the effects of CIH. The antibody reversed the effects of CIH on LPL in adipose tissue and lungs. In conclusion, CIH inactivates LPL by upregulating Angptl4, but inhibition of TG uptake occurs predominantly via an Angptl4/LPL-independent mechanism
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