194 research outputs found
Critical temperature of a fully anisotropic three-dimensional Ising model
The critical temperature of a three-dimensional Ising model on a simple cubic
lattice with different coupling strengths along all three spatial directions is
calculated via the transfer matrix method and a finite size scaling for L x L
oo clusters (L=2 and 3). The results obtained are compared with available
calculations. An exact analytical solution is found for the 2 x 2 oo Ising
chain with fully anisotropic interactions (arbitrary J_x, J_y and J_z).Comment: 17 pages in tex using preprint.sty for IOP journals, no figure
Estudos filogenéticos e de diversidade em Capsicum e sua aplicação na conservação e uso de recursos genéticos das espécies C. frutescens E C. chinense.
No presente trabalho, estudou-se a variabilidade genética de um banco de germoplasma com 115 acessos de C. frutescense 480 de C. chinense visando subsidar açÔes de conservação e uso dos recursos genéticos.Resumo CBRG 269
Influence of the APOE genotypes in some atherosclerotic risk factors
The aim of this work was to study the distribution of apolipoprotein E (APOE) genotypes and their association with some atherosclerotic risk factors, all of them modifiable: total, HDL and LDL cholesterol, triglycerides, systolic and diastolic blood pressure, BMI, waist circumference and smoking. The sample population was constituted of 672 healthy subjects recruited in the Lisbon area. Lipids were quantified by usual automatic enzymatic methods and the APOE genotypes performed in accordance with Hixson and Vernier. Blood pressure measurement and hypertension classification followed international specifications. The frequency distribution of APOE alleles was: epsilon2 = 6.4%, epsilon3 = 83.6% and epsilon4 = 10.0% and the more prevalent genotypes were epsilon2/epsilon3, epsilon3/epsilon3 and epsilon3/epsilon4 respectively 11.0%, 70.1% and 16.1%. We could only observe associations among the most prevalent genotypes and lipids, always statistically significant, specially when the epsilon4 allele was present which was even proved by an higher prevalence of epsilon4 in dyslipidemic subjects with the only exception of those with low HDL-c values. A stronger intervention in the epsilon4 carriers is so recommended through appropriate intervention measures on the connected modifiable risk factors
The preyssler-type polyoxotungstate exhibits anti-quorum sensing, antibiofilm, and antiviral activities
The increase in bacterial resistance to antibiotics has led researchers to find new compounds or find combinations between different compounds with potential antibacterial action and
with the ability to prevent the development of antibiotic resistance. Polyoxotungstates (POTs) are
inorganic clusters that may fulfill that need, either individually or in combination with antibiotics.
Herein, we report the ability of the polyoxotungstates (POTs) with Wells-Dawson P2W18, P2W17,
P2W15, and Preyssler P5W30 type structures to differently affect Gram-negative and Gram-positive
microorganisms, either susceptible or resistant to antibiotics. The compound P5W30 showed the
highest activity against the majority of the tested bacterial strains in comparison with the other tested
POTs (P2W15, P2W17 and P2W18) that did not show inhibition zones for the Gram-negative bacteria,
A. baumanii I73775, E. coli DSM 1077, E. coli I73194, K. pneumoniae I7092374, and P. aeruginosa C46281).
Generally, the results evidenced that Gram-positive bacteria are more susceptible to the POTs tested.
The compound P5W30 was the one most active against S. aureus ATCC 6538 and MRSA16, reaching
<0.83 mg·mLâ1
(100 ”M) and 4.96 mg·mLâ1
(600 ”M), respectively. Moreover, it was verified by
NMR spectroscopy that the most promising POT, P5W30, remains intact under all the experimental
conditions, after 24 h at 37 âŠC. This prompted us to further evaluate the anti-quorum sensing activity
of P5W30 using the biosensor Chromobacterium violaceum CV026, as well as its antibiofilm activity
both individually and in combination with the antibiotic cefoxitin against the methicillin-resistant
Staphylococcus aureus 16 (MRSA16). P5W30 showed a synergistic antibacterial effect with the antibiotic
cefoxitin and chloramphenicol against MRSA16. Moreover, the antibiofilm activity of P5W30 was
more pronounced when used individually, in comparison with the combination with the antibioticcefoxitin. Finally, the antiviral activity of P5W30 was tested using the coliphage QÎČ, showing a dosedependent response. The maximum inactivation was observed at 750 ”M (6.23 mg·mLâ1
). In sum,
P5W30 shows anti-quorum sensing and antibiofilm activities besides being a potent antibacterial
agent against S. aureus and to exhibit antiviral activities against enteric viruses.info:eu-repo/semantics/publishedVersio
Genetic variability of a Brazilian Capsicum frutescens germplasm collection using morphological characteristics and SSR markers.
Characterization studies provide essential information for the conservation and use of germplasm in plant breeding programs. In this study, 103 Capsicum frutescens L. accessions from the Active Germplasm Bank of Embrapa Hortaliças, representative of all five Brazilian geographic regions, were characterized based on morphological characteristics and microsatellite (or simple sequence repeat - SSR) molecular markers. Morphological characterization was carried out using 57 descriptors, and molecular characterization was based on 239 alleles from 24 microsatellite loci. From the estimates of genetic distances among accessions, based on molecular characterization, a cluster analysis was carried out, and a dendrogram was established. Correlations between morphological and molecular variables were also estimated. Twelve morphological descriptors were monomorphic for the set of C. frutescens accessions, and those with the highest degree of polymorphism were stem length (14.0 to 62.0 cm), stem diameter (1.0 to 4.2 cm), days to flowering (90 to 129), days to fruiting (100 to 140), fruit weight (0.1 to 1.4 g), fruit length (0.6 to 4.6 cm), and fruit wall thickness (0.25 to 1.5 mm). The polymorphism information content for the SSR loci varied from 0.36 (EPMS 417) to 0.75 (CA49), with an overall mean of 0.57. The correlation value between morphological and molecular characterization data was 0.6604, which was statistically significant. Fourteen accessions were described as belonging to the morphological type tabasco, 85 were described as malagueta, and four were malaguetinha, a morphological type confirmed in this study. The typical morphological pattern of malagueta was described. Six similarity groups were established for C. frutescens based on the dendrogram and are discussed individually. The genetic variability analyzed in the study highlights the importance of characterizing genetic resources available for the development of new C. frutescens cultivars with the potential for various niche markets
Agronomic descriptors and ornamental potential of passion fruit species.
Abstract: Brazil has great variability, being one of the centers of origin of the genus Passiflora. Passion fruit has a multiple and diversified uses, being little explored as an ornamental plant in the country. The objective of this work was to characterize four passion fruit genotypes (two hybrid materials from the experimental field of passion fruit breeding program of the University of BrasĂlia, and two passion fruit cultivars - BRS SertĂŁo Forte and BRS Mel do Cerrado, both of them from Brazil), based on official and validated morphoagronomic descriptors for the identification of morphological aspects and ornamental potential, under field conditions, in the Distrito Federal, Brazil. The experiment consisted of a randomized block design, with four treatments, four replications, and six plants per plot. Plants were analyzed weekly regarding the characteristics of the branches, leaf blade, petiole, and flowers, with 24 measurements of each structure in the four treatments, which were recorded using a digital camera. Flowers presented pronounced size and color, colored branches, and leaves of varying sizes and shapes. All materials studied showed commercial ornamental potential to be explored as new options for ornamental climbing plants
Active flow control systems architectures for civil transport aircraft
Copyright @ 2010 American Institute of Aeronautics and AstronauticsThis paper considers the effect of choice of actuator technology and associated power systems architecture on the mass cost and power consumption of implementing active flow control systems on civil transport aircraft. The research method is based on the use of a mass model that includes a mass due to systems hardware and a mass due to the system energy usage. An Airbus A320 aircraft wing is used as a case-study application. The mass model parameters are based on first-principle physical analysis of electric and pneumatic power systems combined with empirical data on system hardware from existing equipment suppliers. Flow control methods include direct fluidic, electromechanical-fluidic, and electrofluidic actuator technologies. The mass cost of electrical power distribution is shown to be considerably less than that for pneumatic systems; however, this advantage is reduced by the requirement for relatively heavy electrical power management and conversion systems. A tradeoff exists between system power efficiency and the system hardware mass required to achieve this efficiency. For short-duration operation the flow control solution is driven toward lighter but less power-efficient systems, whereas for long-duration operation there is benefit in considering heavier but more efficient systems. It is estimated that a practical electromechanical-fluidic system for flow separation control may have a mass up to 40% of the slat mass for a leading-edge application and 5% of flap mass for a trailing-edge application.This work is funded by the Sixth European Union Framework Programme as part of the AVERT project (Contract No. AST5-CT-2006-030914
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