Symmetric eikonal model for projectile-electron excitation and loss in relativistic ion-atom collisions

At impact energies $\stackrel{>}{\sim}1$ GeV/u the projectile-electron excitation and loss occurring in collisions between highly charged ions and neutral atoms is already strongly influenced by the presence of atomic electrons. In order to treat these processes in collisions with heavy atoms we generalize the symmetric eikonal model, used earlier for considerations of electron transitions in ion-atom collisions within the scope of a three-body Coulomb problem. We show that at asymptotically high collision energies this model leads to an exact transition amplitude and is very well suited to describe the projectile-electron excitation and loss at energies above a few GeV/u. In particular, by considering a number of examples we demonstrate advantages of this model over the first Born approximation at impact energies $\sim 1$--30 GeV/u, which are of special interest for atomic physics experiments at the future GSI facilities.Comment: 14 pages, 5 figure

Caracterização do pó da casca de coco verde usado como substrato agrícola.

O aumento do consumo de agua-de-coco verde e a vocacao natural para sua industrializacao vem causando problema de disposicao final do residuo gerado, ou seja, as cascas do fruto. A analise do comportamento historico da oferta de coco verde no mercado demonstra crescimento significativo.bitstream/CNPAT-2010/5862/1/Ct-054.pd

Construction and use of a tubular picrate ion-selective electrode for reducing sugar determination in Port wine by flow-injection analysis

A picrate ion-selective electrode without inner reference solution and based on bis(triphenylphosphoranylidene)ammonium picrate dissolved in 2-nitrophenyloctyl ether was constructed and its characteristics assessed. With respect to reducing sugar determination in Port wine, a tubular electrode based on the same sensor system was developed and incorporated into a flow-injection manifold devised for this determination. The methodology involves a reaction between the reducing sugar and picric acid, the decrease in the picrate concentration being monitored with the tubular electrode. A linear dependence between peak width, at a fixed potential and the logarithm of sugar concentration in the range 25–200 g l−1 was obtained. The proposed system allows wine samples to be injected with no previous treatment and allows a sample throughput of 50 determinations per hour, a relative standard deviation less than 4%, and the results are comparable to the reference procedures

Exploring Neutral Hydrogen and Galaxy Evolution with the SKA

One of the key science drivers for the development of the SKA is to observe the neutral hydrogen, HI, in galaxies as a means to probe galaxy evolution across a range of environments over cosmic time. Over the past decade, much progress has been made in theoretical simulations and observations of HI in galaxies. However, recent HI surveys on both single dish radio telescopes and interferometers, while providing detailed information on global HI properties, the dark matter distribution in galaxies, as well as insight into the relationship between star formation and the interstellar medium, have been limited to the local universe. Ongoing and upcoming HI surveys on SKA pathfinder instruments will extend these measurements beyond the local universe to intermediate redshifts with long observing programmes. We present here an overview of the HI science which will be possible with the increased capabilities of the SKA and which will build upon the expected increase in knowledge of HI in and around galaxies obtained with the SKA pathfinder surveys. With the SKA1 the greatest improvement over our current measurements is the capability to image galaxies at reasonable linear resolution and good column density sensitivity to much higher redshifts (0.2 < z < 1.7). So one will not only be able to increase the number of detections to study the evolution of the HI mass function, but also have the sensitivity and resolution to study inflows and outflows to and from galaxies and the kinematics of the gas within and around galaxies as a function of environment and cosmic time out to previously unexplored depths. The increased sensitivity of SKA2 will allow us to image Milky Way-size galaxies out to redshifts of z=1 and will provide the data required for a comprehensive picture of the HI content of galaxies back to z~2 when the cosmic star formation rate density was at its peak.Comment: 25 pages, 5 figures, 3 tables. Contribution to the conference 'Advancing Astrophysics with the Square Kilometre Array', June 8-13, 2014, Giardini Naxos, Ital

Parâmetros genéticos para características reprodutivas de um rebanho da raça Santa Inês criado no Semiárido nordestino.

Resumo: Com o objetivo de estimar os parâmetros genéticos para características reprodutivas da raça Santa Inês, criado no semiárido nordestino, foram utilizadas informações do rebanho pertencente a Embrapa Caprinos e Ovinos, localizada no município de Sobral, no estado do Ceará, ocorridas entre os anos de 2006 e 2013. As estimativas dos parâmetros genéticos e fenotípicos foram obtidas para as características intervalo de partos (IEP), dias para o parto (DP), período de gestação (PG) e número de serviços por concepção (NSC), pelo método da Máxima Verossimilhança Restrita, utilizando o algoritmo livre de derivadas DFREML, sob modelo animal multicaracterística, usando o software Multiple Trait Derivative-Free Restricted Maximum Likelihood (MTDFREML). As estimativas de herdabilidade para IEP, DP, PG e NSC foram 0,07, 0,07, 0,60 e 0,68, respectivamente. Os valores estimados neste estudo indicam que o fenótipo não é um bom indicador do genótipo para IEP e DP, havendo forte influência de fatores ambientais na expressão destas características. É importante considerar a possibilidade de viés com a seleção para IEP neste rebanho, por conta do uso de estações de monta anuais. [Genetic parameters for reproductive traits in a flock of Santa Inês sheep breed raised in Semiarid northeastern] Abstract: In order to estimate genetic parameters for reproductive traits of Santa Inês sheep breed, raised in semiarid northeastern, were used information from the flock belonging to Embrapa Goats and Sheep, located in Sobral, Ceará state, occurred between the years 2006 and 2013. Estimates of genetic and phenotypic parameters for lambing interval (IEP), lambing date (DP), gestation length (PG) and number of services per conception (NSC) were obtained by Restricted Maximum Likelihood method using the derivative-free algorithm DFREML under multi-trait animal model using the software Multiple Trait Derivative-Free Restricted Maximum Likelihood (MTDFREML). The heritabilities estimated for IEP, DP, PG and NSC were 0.07, 0.07, 0.60 and 0.68, respectively. The values estimated in this study indicate that the phenotype is not a good indicator of genotype for IEP and DP, with strong influence of environmental factors on the expression of these traits. It is important to consider the possibility of bias to this selection for IEP in this flock, due to the use of annual breeding seasons

Palaeoecological analysis of two Late Pleistocene continental mollusc assemblages from Uruguay

Ponencia presentada en World Congress of Malacology, 1-5 Aug. 2022, Münich - Alemania, organizado por UNITAS Malacologica y Ludwig-Maximilians-Universität.Extant continental (freshwater and terrestrial) molluscs are very informative from an environmental point of view. The specific environmental requirements of different taxa can be extrapolated to the fossil assemblages in order to reconstruct past environments. This is especially true for the Quaternary, when fossil assemblages are mostly composed by extant species. We analysed two associations of continental molluscs from the Late Pleistocene of Uruguay, with the goal of reconstruct the depositional environments for each assemblage. For this analysis, 11 localities from the Sopas Formation and 10 from the Dolores Formation were selected. The statistical analyses aimed to understand the diversity of each locality and to make comparisons among them, using traditional diversity indices (Shannon, Simpson, Equitability). To estimate the diversity Rarefaction and Chao1 were applied. Lastly, the species occurrence in all localities were compared, using several multivariate analyses: NMDS with axes rotation by Principal Components Analysis, Correspondence Analysis, and Cluster Analysis. The multivariate analyses show that all local assemblages are distributed in two main associations: one composed mostly by Sopas Formation localities (Sopas Association) and the other composed mostly by Dolores Formation localities (Dolores Association). Only one locality from each Formation was interchanged. The Sopas Association records mostly the families Cyrenidae (36.1 %), Tateidae (32 %), Cochliopidae (26.1 %), and the only record of the family Chilinidae. Also, the large, massive species Diplodon charruanus, D. wymanii and D. peraeformis are present. Meanwhile, the Dolores Association records mostly representatives of Cochliopidae (54.4 %), Planorbinae (20.2 %), Sphaeridae (16 %), and has the only records of Physidae and Succineidae. Cochliopidae (Heleobia) are present in both associations, which is logical since currently they are quite ubiquitous in most lotic and lentic environments. Ampullariidae and the subfamily Ancylinae are also present in both associations, along with the delicate species Diplodon rhuacoicus, which is the only Diplodon from the Dolores Association. Presently, the communities that include Sopas-like assemblages are mostly found in high to moderate current lotic environments, with rocky to coarse bottoms. Meanwhile, the communities that include the taxa typical of the Dolores Association are common in lentic or very calm lotic environments, with fine sediments and abundant aquatic vegetation.ANII: FCE_3_2018_1_148922ANII: POS_NAC_2015_1_10947

A 15 µm selected sample of hHigh-z starbursts and AGNs

We report results from our Spitzer GO-1 program on IRS spectroscopy of a large sample of Luminous Infrared Galaxies and quasars selected from the European Large Area ISO Survey (ELAIS). The selected ELAIS sources have a wide multi-wavelength coverage, including ISOCAM, ISOPHOT, IRAC and MIPS (from SWIRE), and optical photometry. Here we present the sample selection and results from the IRS spectroscopy

Spectra of sparse non-Hermitian random matrices: an analytical solution

We present the exact analytical expression for the spectrum of a sparse non-Hermitian random matrix ensemble, generalizing two classical results in random-matrix theory: this analytical expression forms a non-Hermitian version of the Kesten-Mckay law as well as a sparse realization of Girko's elliptic law. Our exact result opens new perspectives in the study of several physical problems modelled on sparse random graphs. In this context, we show analytically that the convergence rate of a transport process on a very sparse graph depends upon the degree of symmetry of the edges in a non-monotonous way.Comment: 5 pages, 5 figures, 12 pages supplemental materia