Non-unitary representations of the SU(2) algebra in the Dirac equation with a Coulomb potential

A novel realization of the classical SU(2) algebra is introduced for the Dirac relativistic hydrogen atom defining a set of operators that, besides, allow the factorization of the problem. An extra phase is needed as a new variable in order to define the algebra. We take advantage of the operators to solve the Dirac equation using algebraic methods. To acomplish this, a similar path to the one used in the angular momentum case is employed; hence, the radial eigenfuntions calculated comprise non unitary representations of the algebra. One of the interesting properties of such non unitary representations is that they are not labeled by integer nor by half-integer numbers as happens in the usual angular momentum representation.Comment: 20 pages 1 eps figure in a single zipped file, submitted to J. Math. Phy

Visual Responses of Adult Asian Citrus Psyllid (Hemiptera: Liviidae) to Colored Sticky Traps on Citrus Trees

The effects of five differently-colored sticky traps in capturing adult Diaphorina citri were evaluated in citrus orchards. Trap catches of D. citri were monitored fortnightly on blue, green, red, white and yellow sticky cards placed on three citrus varieties during D. citri active flight period from April to July in south Texas. Evaluation of mean trap catches of each color by repeated measures analysis of variance produced three separate groups: yellow traps caught significantly more D. citri adults than the other four traps; red and green traps caught significantly more D. citri than blue and white traps, which were not significantly different. Although the number of adult psyllid captured on all trap types significantly increased with time during the trapping period, the performance of traps did not change with time. Trap catches were also significantly influenced by the citrus species; traps placed on lemon trees captured more D. citri than those placed on sweet orange and grapefruit, suggesting that plant preference exhibited by D. citri may influence the performance of traps. The ratio of trap reflectance between the 680 to 700 nm and the 450 nm was significantly correlated with total trap catches in all host species studied. Thus, this index was a good indicator of the attractiveness of adult D. citri to colored traps. Additionally, we compared the reflectance values of young versus mature flush shoots of the three host plants used in this study as related to densities of D. citri recorded in colored traps. We discussed the importance of visual cues in the host finding behavior of adult D. citri

Influence of the main cereal and feed form of the rearing phase diets on performance, digestive tract, and body traits of brown-egg laying pullets from hatch to 17 weeks of age

We hypothesize that pullets could respond similarly, independent of feed form, to the feeding of diets based on corn or wheat supplemented with adequate NSP enzymes. Also, pullets would quickly adapt their gastrointestinal tract and modify productive performance accordingly, when switched from crumbles to mash feeds. The aim of this research was to evaluate the effects of feeding crumbles for different periods of time, followed by feeding mash to 17 wk of age, on performance, gastrointestinal tract development, and body measurements of brown-egg laying pullets fed diets based on corn or wheat

La cacería de animales silvestres en la comunidad de bretaña, río puinahua, loreto – perú

This study reports basic information about hunting by the residents of the Bretaña community such as: days required for hunting, wild animals often hunted, types of habitat where it is customary to hunt, among other things. 10 hunters were interviewed, as well as our own personal observations in the study area. Species such as majas (Cuniculus paca) 18.06% and choro (Lagothrix lagotricha) 14.01% were the most hunted. Among the least hunted was pava (Aburria pipile) 0.46%. The restinga was the habitat most frequented by hunters (42%). Ungulates (1365 Kg) and reptiles (754 Kg) were the species which contributed most fresh meat per animal; males (51.23%) were most preferred by hunters. A priority is to involve the community in a management plan that seeks to conserve the species as a whole and its habitat.Este estudio reporta información básica sobre la cacería realizada por los pobladores de la comunidad de Bretaña como: días requeridos para la cacería, animales silvestres frecuentemente cazados, tipos de hábitat donde se acostumbra a cazar, entre otros aspectos. Se realizó una entrevista a 10 cazadores de la zona, además de las observaciones personales en la zona de estudio. Las especies como majas (Cuniculus paca) 18.06% y choro (Lagothrix lagotricha) 14,01% fueron las más cazadas, entre la menos cazada estuvo la pava (Aburria pipile) 0,46%. La restinga representó el hábitat más frecuentado por los cazadores (42%). Los ungulados (1365 Kg) y reptiles (754 Kg) fueron las especies que aportaron mayor rendimiento de carne fresca por animal, siendo los machos (51,23%) los más preferidos por los cazadores. Es prioritario involucrar a la comunidad en un plan de manejo que busque conservar a las especies en su totalidad y su hábitat

Evaluation of potential nirs to predict pastures nutritive value

This paper describes the capability of near infra-reflectance (NIRS) to predict the nutritional quality of pastures from southern Chile (39°-40°S). A Fourier transformed near-infrared (FT-NIR) method for rapid determination of dry matter (DM), crude protein (CP), in vitro digestibility (IVD) and metabolizable energy (ME) was used. Calibration models were developed between chemical and NIRS spectral data using partial least squares (PLS) regression and external validation. The coefficients of determination in calibration (R2c) were high varying between 0.89-0.99 and the root mean square errors of calibration (RMSEC) were low, ranging between 0.46-2.55 for the parameters analysed. The Residual Prediction Deviation (RPD) was higher than 2.5. Our results confirmed the convenience of using a wide range of samples applicability in the calibration set. Data also showed that the use of an independent set of samples for external validation increases the robustness of the models to predict unknown samples. Our results indicated RPD values higher than 2.5 which is the minimum recommended for this type of prediction. Thus, the result showed that NIRS was useful to estimate the nutritional quality of permanent pastures, and has a great potential to be used as a rapid decision tool for the studied analysis.Thanks the Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) post-doc grant n°3120069.info:eu-repo/semantics/publishedVersio