Search for giant planets in M67 IV: survey results

We present the results of a seven-year-long radial velocity survey of a sample of 88 main-sequence and evolved stars to reveal signatures of Jupiter-mass planets in the solar-age and solar-metallicity open cluster M67. We aim at studying the frequency of giant planets in this cluster with respect to the field stars. In addition, our sample is also ideal to perform a long-term study to compare the chemical composition of stars with and without giant planets in detail. We analyzed precise radial velocity (RV) measurements obtained with five different instruments. We conducted Monte Carlo simulations to estimate the occurrence rate of giant planets in our radial velocity survey. All the planets previously announced in this RV campaign with their properties are summarized here: 3 hot Jupiters around the main-sequence stars YBP1194, YBP1514, and YBP401, and 1 giant planet around the evolved star S364. Two additional planet candidates around the stars YBP778 and S978 are also analyzed in the present work. We discuss stars that exhibit large RV variability or trends individually. For 2 additional stars, long-term trends are compatible with new binary candidates or substellar objects, which increases the total number of binary candidates detected in our campaign to 14. Based on the Doppler-detected planets discovered in this survey, we find an occurrence of giant planets of ~18.0%(+12.0/-8.0%) in the selected period-mass range. This frequency is slightly higher but consistent within the errors with the estimate for the field stars, which leads to the general conclusion that open cluster and field statistics agree. However, we find that the rate of hot Jupiters in the cluster (~5.7%(+5.5/-3.0%)) is substantially higher than in the field.Comment: Accepted by A&

Euclidean Supersymmetry, Twisting and Topological Sigma Models

We discuss two dimensional N-extended supersymmetry in Euclidean signature and its R-symmetry. For N=2, the R-symmetry is SO(2)\times SO(1,1), so that only an A-twist is possible. To formulate a B-twist, or to construct Euclidean N=2 models with H-flux so that the target geometry is generalised Kahler, it is necessary to work with a complexification of the sigma models. These issues are related to the obstructions to the existence of non-trivial twisted chiral superfields in Euclidean superspace.Comment: 8 page

Antimicrobial activity of potential essential oils to replace potassium sorbate in fruit preparations

Introduction: In recent years, the food industry has faced the challenge of producing high-quality products using natural preservative alternatives instead of synthetic ones. Essential oils (EO), naturally present in various plants, have potential as alternatives due to their antimicrobial activity and high food safety (Generally Recognized as Safe, GRAS). This study aimed to investigate the antimicrobial activity of EO against common spoilage and pathogenic microorganisms in fruit preparations, to use as a substitute for potassium sorbate (PS). Methodology: The antimicrobial activity of lemongrass and lemon EO was tested using the microdilution method in 96-well plates against Lactobacillus plantarum, Escherichia coli; Candida intermedia, Pichia fermentans, Aspergillus niger and Penicillium glabrum.EO were tested at concentrations ranging from 1.56 to 50% and PS at 0.03 to 4%. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Results: The MICs of lemongrass and lemon EO for E. coli were 3.12 and 12.5%, respectively, while for L. plantarum, they were 1,56 and 6.25% respectively. Regarding the yeasts, the MIC of lemongrass and lemon EO for C. intermedia were 1.56 and 3.12%, respectively, and for P. fermentans, they were 1.56 and 1.56%, respectively. Lemongrass EO showed the same MICs value of 6.25% against A. niger, and P. glabrum. Lemon EO also displayed the same MICs values of 25% for A. niger, and P. glabrum representing the highest MICs values observed. The MBCs values was similar the MICs values to all microorganisms except to L. plantarum that were 6.25 and 25% to lemongrass and lemon EO, respectively. PS showed MICs values of 1 and 2% for E. coli and L. plantarum, respectively, with MBCs values of 2% for both. For yeasts, the MIC was 0.06% for both with MBC values of 0.06% for E. coli and 0.5% for L. plantarum. The MIC and MBC values were the same of 0.06% for both fungi. Conclusion: The EO tested showed significant antimicrobial potential at low concentrations, particularly lemongrass EO. Future studies will incorporate this oil as substitutes for PS to verify their ability to maintain antimicrobial effectiveness over time when incorporated in fruit preparations.info:eu-repo/semantics/publishedVersio

Avaliação de linhagens intermediárias de feijoeiro comum do grupo comercial carioca no agreste nordestino.

Este trabalho teve por objetivo avaliar o comportamento produtivo de linhagens intermediárias de feijoeiro comum do grupo comercial preto em áreas do Agreste nordestino

Superconducting and normal-state interlayer-exchange-coupling in La0.67_{0.67}Sr0.33_{0.33}MnO3{3}-YBa2_{2}Cu3_{3}O7−La_{7}-La_{0.67}SrSr_{0.33}MnO MnO{3}$ epitaxial trilayers

The issue of interlayer exchange coupling in magnetic multilayers with superconducting (SC) spacer is addressed in La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (LSMO) - YBa$_{2}$Cu$_{3}$O$_{7}$ (YBCO) - La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (LSMO) epitaxial trilayers through resistivity, ac-susceptibility and magnetization measurements. The ferromagnetic (FM) LSMO layers possessing in-plane magnetization suppress the critical temperature (T$_{c})$ of the c-axis oriented YBCO thin film spacer. The superconducting order, however, survives even in very thin layers (thickness d$_{Y} \sim$ 50 {\AA}, $\sim$ 4 unit cells) at T $<$ 25 K. A predominantly antiferromagnetic (AF) exchange coupling between the moments of the LSMO layers at fields $<$ 200 Oe is seen in the normal as well as the superconducting states of the YBCO spacer. The exchange energy J$_{1}$ ($\sim$ 0.08 erg/cm$^{2}$ at 150 K for d$_{Y}$ = 75 {\AA}) grows on cooling down to T$_{c}$, followed by truncation of this growth on entering the superconducting state. The coupling energy J$_{1}$ at a fixed temperature drops exponentially with the thickness of the YBCO layer. The temperature and d$_{Y}$ dependencies of this primarily non-oscillatory J$_{1}$ are consistent with the coupling theories for systems in which transport is controlled by tunneling. The truncation of the monotonic T dependence of J$_{1}$ below T$_{c}$ suggests inhibition of single electron tunneling across the CuO$_{2}$ planes as the in-plane gap parameter acquires a non-zero value.Comment: Accepted for publication in Phys. Rev.

Indutores de resistência no controle de Fusarium solani f. sp. piperis in vitro.

Resumos do 42º Congresso Brasileiro de Fitopatologia

Comportamento de linhagens de feijoeiro do grupo preto na zona agreste do nordeste brasileiro.

O objetivo deste trabalho foi o de avaliar linhagens de feijoeiro do grupo comercial preto para as condições do Agreste nordestino

Avaliação de genótipos de feijoeiro comum do grupo comercial carioca cultivados nas épocas das águas e do inverno em Uberlândia, Estado de Minas Gerais.

O feijoeiro é uma das principais culturas do país, e o Estado de Minas Gerais é um dos maiores produtores, representando cerca de 15% da produção nacional. O objetivo deste trabalho foi testar o desempenho de linhagens de feijoeiro comum cultivadas nas épocas das águas e do inverno, na região do Triângulo Mineiro, Minas Gerais. No cultivo das águas (semeadura em dezembro de 2005) e do inverno (semeadura em maio de 2006), as linhagens/cultivares testadas foram BRS Horizonte, CNFC 8059, CNFC 8065, CNFC 8075, VC-6, VC-7, VC-8, VC-9, VC-10, VC-11, VC-12, CNFC 10443, CNFC 10453, CNFC 10476, MA-I-2.5, MA-I-8.9, MA-I-18.13, RC-I-8, CV-46, CV-55 e Z-22, além das testemunhas BRSMG Majestoso, Pérola e BRSMG Talismã e VC-3. Em cada experimento, o delineamento experimental foi o de blocos casualizados com 25 tratamentos, em três repetições, a parcela útil foi de 4 m². No cultivo das águas, os rendimentos das linhagens mais produtivas variaram entre 2,69 e 2,78 t ha-1 (VC-9 e VC-10, respectivamente) e, no inverno, alcançaram 3 t ha-1 (3,01 e 3,00 t ha-1, CNFC 8065 e Z-22, respectivamente). De maneira geral, as linhagens foram mais produtivas no cultivo do inverno, embora a interação entre linhagens e época de cultivo tenha indicado desempenho distinto entre elas em relação à época