Magnetic field and wind of Kappa Ceti: towards the planetary habitability of the young Sun when life arose on Earth

We report magnetic field measurements for Kappa1~Cet, a proxy of the young Sun when life arose on Earth. We carry out an analysis of the magnetic properties determined from spectropolarimetric observations and reconstruct its large-scale surface magnetic field to derive the magnetic environment, stellar winds and particle flux permeating the interplanetary medium around Kappa1~Cet. Our results show a closer magnetosphere and mass-loss rate of Mdot = 9.7 x 10^{-13} Msol/yr, i.e., a factor 50 times larger than the current solar wind mass-loss rate, resulting in a larger interaction via space weather disturbances between the stellar wind and a hypothetical young-Earth analogue, potentially affecting the planet's habitability. Interaction of the wind from the young Sun with the planetary ancient magnetic field may have affected the young Earth and its life conditionsComment: 6 pages, 5 figures, Published at the Astrophysical Journal Letters (ApJL): Manuscript #LET3358

A cultura do girassol.

Introdução. Exigências climáticas. Escolha de área. Correção da acidez. Preparo do solo. Preparo convencional.Semeadura direta. Controle de plantas daninhas. Controle mecânico de plantas daninhas. Herbicidas para o manejo de plantas daninhas na semeadura direta. Herbicidas registrados para a cultura do girassol. Resíduo de herbicidas na cultura do girassol. Adubação. Época de semeadura. Semeadura. Espaçamento e densidade. Doenças. Pragas. Colheita. Custo de produção e rentabilidade da cultura do girassol. Literatura consultada.bitstream/item/77468/1/CNPSO-CIR.-TEC.-13-96.pd

A cultura do girassol.

Exigencias climaticas; Escolha de area; Correcao da acidez; Preparo do solo; Controle de plantas daninhas; Adubacao; Epoca de semeadura; Espacamento e densidade; Doencas; Pragas; Colheita; Custo de producao e rentabilidade da cultura do girassol.bitstream/item/42696/1/ID-2434.pd

Evaluation of the genotoxicity induced by the fungicide fenarimol in mammalian and plant cells by use of the single-cell gel electrophoresis assay.

Fenarimol, a systemic pyrimidine carbinol fungicide, is considered to be not genotoxic or weakly genotoxic, although the available toxicological data are controversial and incomplete. Our results obtained in vitro with leukocytes of two different rodent species (rat and mouse) show that fenarimol affects DNA, as detected by the single-cell gel electrophoresis (SCGE, Comet) assay. This fungicide is able to induce DNA damage in a dose-related manner, with significant effectiveness at 36 nM, but without significant interspecies differences. Simultaneous exposure of rat leukocytes to fenarimol (36-290nM) and a model genotoxic compound (50 ?g/ml bleomycin) produced a supra-additive cytotoxic and genotoxic effect. This supports previous findings suggesting possible co-toxic, co-mutagenic, cancer-promoting and co-carcinogenic potential of fenarimol, and modification of the effects of other xenobiotics found to be influenced by this agrotoxic chemical, with consequent different toxicological events. The potential for DNA strand breaks to act as a biomarker of genetic toxicity in plants in vivo was also considered, in view of the fact that higher plants represent reliable sensors in an ecosystem. Significant DNA breakage was observed in the nuclei of Impatiens balsamina leaves after in vivo treatment with fenarimol (145 nM, 1 h). More than 50% of the cells showed such DNA damage

Genetic variability in pecan genotypes in Brazil.

Pecan crops has been expanding in recent years, mainly in southern Brazil. Genotypes that compose Brazilian orchards come from the USA and from selections of plants made by Brazilian producers. This study aimed to characterize with microsatellite markers pecan cultivars registered for cultivation in Brazil, including some selections made in the country. It is important to know the genetic variability of the pecan tree, as it facilitates the identification of possible phytotechnical deficiencies due to the genetic similarity between the plants, in addition to helping in the conservation of the species, among other. Thirty-four, out of forty collected accessions, were genotyped with 11 selected SSR (Simple Sequence Repeats) loci. Twenty-four polymorphic alleles were identified. The genetic similarity matrix, based on the Jaccard coefficient, ranged from 0.125 to 1.0; general mean of similarity was 0.46. The cluster analysis, which was carried out by the Unweighted Pair Group Method with Arithmetic Mean (UPGMA), classified pecan accessions into four main groups. Results showed that there is high genetic variability in germplasm evaluated, although some accessions may be duplicates

Calculation of excited polaron states in the Holstein model

An exact diagonalization technique is used to investigate the low-lying excited polaron states in the Holstein model for the infinite one-dimensional lattice. For moderate values of the adiabatic ratio, a new and comprehensive picture, involving three excited (coherent) polaron bands below the phonon threshold, is obtained. The coherent contribution of the excited states to both the single-electron spectral density and the optical conductivity is evaluated and, due to the invariance of the Hamiltonian under the space inversion, the two are shown to contain complementary information about the single-electron system at zero temperature. The chosen method reveals the connection between the excited bands and the renormalized local phonon excitations of the adiabatic theory, as well as the regime of parameters for which the electron self-energy has notable non-local contributions. Finally, it is shown that the hybridization of two polaron states allows a simple description of the ground and first excited state in the crossover regime.Comment: 12 pages, 9 figures, submitted to PR

Magnetic field and wind of Kappa Ceti: toward the planetary habitability of the young sun when life arose on earth

We report magnetic field measurements for κ1 Cet, a proxy of the young Sun when life arose on Earth. We carry out an analysis of the magnetic properties determined from spectropolarimetric observations and reconstruct the large-scale surface magnetic field to derive the magnetic environment, stellar winds, and particle flux permeating the interplanetary medium around k1 Cet. Our results show a closer magnetosphere and mass-loss rate of M = 9.7 ́ 10-13 M yr-1, i.e., a factor of 50 times larger than the current solar wind mass-loss rate, resulting in a larger interaction via space weather disturbances between the stellar wind and a hypothetical young-Earth analogue, potentially affecting the planet’s habitability. Interaction of the wind from the young Sun with the planetary ancient magnetic field may have affected the young Earth and its life conditions

The MIDAS telescope for microwave detection of ultra-high energy cosmic rays

We present the design, implementation and data taking performance of the MIcrowave Detection of Air Showers (MIDAS) experiment, a large field of view imaging telescope designed to detect microwave radiation from extensive air showers induced by ultra-high energy cosmic rays. This novel technique may bring a tenfold increase in detector duty cycle when compared to the standard fluorescence technique based on detection of ultraviolet photons. The MIDAS telescope consists of a 4.5 m diameter dish with a 53-pixel receiver camera, instrumented with feed horns operating in the commercial extended C-Band (3.4 -- 4.2 GHz). A self-trigger capability is implemented in the digital electronics. The main objectives of this first prototype of the MIDAS telescope - to validate the telescope design, and to demonstrate a large detector duty cycle - were successfully accomplished in a dedicated data taking run at the University of Chicago campus prior to installation at the Pierre Auger Observatory.Comment: 13 pages, 18 figure

Minimal Model Holography

We review the duality relating 2d W_N minimal model CFTs, in a large N 't Hooft like limit, to higher spin gravitational theories on AdS_3.Comment: 54 pages, 1 figure; Contribution to J. Phys. A special volume on "Higher Spin Theories and AdS/CFT" edited by M. R. Gaberdiel and M. Vasiliev. v2. minor change