The Dynamical Behaviour of Test Particles in a Quasi-Spherical Spacetime and the Physical Meaning of Superenergy

We calculate the instantaneous proper radial acceleration of test particles (as measured by a locally defined Lorentzian observer) in a Weyl spacetime, close to the horizon. As expected from the Israel theorem, there appear some bifurcations with respect to the spherically symmetric case (Schwarzschild), which are explained in terms of the behaviour of the superenergy, bringing out the physical relevance of this quantity in the study of general relativistic systems.Comment: 14 pages, Latex. 4 figures. New references added. Typos corrected. To appear in Int. J. Theor. Phy

Scanner image methodology (SIM) to measure dimensions of leaves for agronomical applications

A scanner image methodology was used to determine plant dimensions, such as leaf area, length and width. The values obtained using SIM were compared with those recorded by the LI-COR leaf area meter. Bias, linearity, reproducibility and repeatability (R&R) were evaluated for SIM. Different groups of leaves were scanned and measured. R&R studies showed that, the lowest SIM’s resolution was nineteen categories. SIM’s R&R ANOVA showed the method’s measurement error was not significant. In the image processing method, the color image was converted to gray scale over the green band and it was segmented using Otsu methodology. The noise produced was cleaned with a median filter. The leaf image was rotated to align the longest parallel line to y-axis or x-axis using central moments. From the centroid using directional erosions the leaf width and length were obtained and recorded.Key words: Leaf area, width, length, digital image analysis, segmentation

Análise multivariada de características de carcaça e qualidade da carne de ovinos.

Resumo: Técnicas de análise multivariada foram utilizadas para avaliação de características de carcaça e qualidade da carne de cordeiros: Morada Nova (MN), Somalis Brasileira (SB), Santa Inês (SI) e ½ Dorper x ½ Morada Nova (F1). Na análise fatorial, os cinco primeiros fatores extraídos por componentes principais explicaram 80 % da variância total dos dados. Os escores calculados para cada fator foram utilizados na análise de variância. Houve efeito significativo do grupo genético para os fatores 1, 3 e 4. O primeiro fator é o processo que representa às características morfométricas da carcaça, os pesos ao abate e da carcaça, os pesos dos cortes comerciais e a área de olho de lombo, sendo a raça SI superior às raças SB e MN, porém similar ao genótipo F1. Esse fator explica 52,65 % da variância total dos dados. Quanto ao terceiro (espessura de gordura e intensidade de vermelho da carne) e ao quarto fator (índice de quebra por resfriamento e perda de peso por cocção) a raça SB apresentou maior especificidade, diferindo dos demais grupos. Para o segundo fator (pH medido 24 horas post mortem, luminosidade da carne e intensidade de amarelo) e para o quinto (força de cisalhamento) não houve diferença entre os grupos genéticos. Através da análise exploratória dos dados foi possível reduzir a dimensionalidade do conjunto de informações e identificar diferenças entre grupos considerando o processo formado pelas combinações lineares das características mais associadas entre si (fatores). [Multivariate analysis of carcass and meat quality traits in sheep]. Abstract: Multivariate analyzes were used for evaluation of carcass and meat quality traits of lambs: Morada Nova (MN), Brazilian Somalis (BS), Santa Inês (SI) and ½Dorper x ½Morada Nova (F1). In the factor analysis, the first five factors extracted by principal components explained 80 % of total variance. The factor scores were used in the analysis of variance. The first factor is the process that represents the carcass morphometric traits, to slaughter weights and commercial cuts weights and loin eye area, and SI breed similar to genotype F1, but higher than the races SB and MN. This factor explained 52.65% of the total variance. The third (fat thickness and redness of meat) and the fourth factor (drip loss and cooking loss), SB genotype showed higher specificity, differing from other groups. For the second factor (pH measured 24 hours post mortem, lightness of meat and yellowness of meat) and the fifth factor (shear force) there was no difference between genotypes. Through exploratory analysis of the data was possible to reduce the dimensionality of the information and identify differences among genotypes considering the process formed by linear combinations of the traits more associated with each other (factors)

The nature of domain walls in ultrathin ferromagnets revealed by scanning nanomagnetometry

The recent observation of current-induced domain wall (DW) motion with large velocity in ultrathin magnetic wires has opened new opportunities for spintronic devices. However, there is still no consensus on the underlying mechanisms of DW motion. Key to this debate is the DW structure, which can be of Bloch or N\'eel type, and dramatically affects the efficiency of the different proposed mechanisms. To date, most experiments aiming to address this question have relied on deducing the DW structure and chirality from its motion under additional in-plane applied fields, which is indirect and involves strong assumptions on its dynamics. Here we introduce a general method enabling direct, in situ, determination of the DW structure in ultrathin ferromagnets. It relies on local measurements of the stray field distribution above the DW using a scanning nanomagnetometer based on the Nitrogen-Vacancy defect in diamond. We first apply the method to a Ta/Co40Fe40B20(1 nm)/MgO magnetic wire and find clear signature of pure Bloch DWs. In contrast, we observe left-handed N\'eel DWs in a Pt/Co(0.6 nm)/AlOx wire, providing direct evidence for the presence of a sizable Dzyaloshinskii-Moriya interaction (DMI) at the Pt/Co interface. This method offers a new path for exploring interfacial DMI in ultrathin ferromagnets and elucidating the physics of DW motion under current.Comment: Main text and Supplementary Information, 33 pages and 12 figure

NOEMA Observations of a Molecular Cloud in the low-metallicity Galaxy Kiso 5639

A giant star-forming region in a metal-poor dwarf galaxy has been observed in optical lines with the 10-m Gran Telescopio Canarias and in the emission line of CO(1-0) with the NOEMA mm-wave interferometer. The metallicity was determined to be 12+log(O/H)=7.83+-0.09, from which we estimate a conversion factor of alpha_CO~100 Msun/pc2/(K km/s) and a molecular cloud mass of ~2.9x10^7 Msun. This is an enormous concentration of molecular mass at one end of a small galaxy, suggesting a recent accretion. The molecular cloud properties seem normal: the surface density, 120 Msun/pc2, is comparable to that of a standard giant molecular cloud, the cloud's virial ratio of ~1.8 is in the star-formation range, and the gas consumption time, 0.5 Gyr, at the present star formation rate is typical for molecular regions. The low metallicity implies that the cloud has an average visual extinction of only 0.8 mag, which is close to the threshold for molecule formation. With such an extinction threshold, molecular clouds in metal-poor regions should have high surface densities and high internal pressures. If high pressure is associated with the formation of massive clusters, then metal-poor galaxies such as dwarfs in the early universe could have been the hosts of metal-poor globular clusters.Comment: 4 pages and 4 figures. accepted by ApJ

Conception rate of artificially inseminated holstein cows affected by cloudy vaginal mucus, under intense heat conditions.

The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services), raised under intense heat (mean annual temperature of 22°C), at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses). The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1?21.7%). The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%). Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.Título em português: Taxa de concepção de vacas Holandesas inseminadas artificialmente e afetadas por muco vaginal turvo, sob condições de intenso calor

On the development of strong ridge episodes over the eastern North Atlantic

The occurrence of strong and persistent mid-latitude anticyclonic ridges over the Eastern North Atlantic is a major contributor to the occurrence of severe winter droughts over Western Iberia. We analyze the development of strong and persistent ridge episodes within 40–50°N; 40°W–5°E, which are defined as 300 hPa geopotential height anomalies above 50 gpm that persist for at least 10 consecutive days. Results suggest that the generation and maintenance of these episodes, with positive stratospheric geopotential anomalies over the North American continent and the adjacent North Pacific, are associated with an intensified polar jet. Such positive anomalies tend to detach from the main stratospheric anomaly and propagate eastwards and downwards as Rossby tropospheric waves. Furthermore, the Eastern North Atlantic ridge is generated and repeatedly reinforced until the stratospheric anomaly dissipates. Results also show evidence for waves breaking anticyclonically during the episodes, which is dynamically coherent with their persistency and quasi-stationarity

Duration of heat treatment and true digestibility of amino acids in meat meal for Leghorn cockerels

Knowledge of the true digestibility of amino acids in the ingredients of a poultry ration is important in order to use them properly, especially the proteinic ingredients that have been heated during processing, such as meat meal. Protein solubility is a good indicator of heat damage. To estimate true digestibility, Leghorn White cockerels were fasted for 24 h and then force fed with meat meal autoclaved at 121°C and 1.5 kg/cm2 for 0, 15, 30, 45 and 60 minutes. A correction for endogenous amino acids was included. Nitrogen was determined by micro Kjeldahl; protein solubility by the methods of 2% KOH and coomassie blue; amino acids concentrations were also determined by HPLC. Treatments had an effect (P<.05) on meat meal protein solubility, means being 89% and 84% for the KOH and coomassie blue methods, respectively. However, protein solubility increased until 30 minutes and then decreased according to the KOH method, whereas it increased until 15 minutes (P<.05) and then remained constant by the coomassie blue method. Autoclaving had an effect on true digestibility of all amino acids, except methionine. There was a high and significant correlation (0.81) between protein solubility by the KOH method and true digestibility of amino acids

Strange stars in Krori-Barua space-time

The singularity space-time metric obtained by Krori and Barua\cite{Krori1975} satisfies the physical requirements of a realistic star. Consequently, we explore the possibility of applying the Krori and Barua model to describe ultra-compact objects like strange stars. For it to become a viable model for strange stars, bounds on the model parameters have been obtained. Consequences of a mathematical description to model strange stars have been analyzed.Comment: 9 pages (two column), 12 figures. Some changes have been made. " To appear in European Physical Journal C