Meson decay in a corrected 30P3^P_0 model

Extensively applied to both light and heavy meson decay and standing as one of the most successful strong decay models is the $3^P_0$ model, in which $q\bar{q}$ pair production is the dominant mechanism. The pair production can be obtained from the non-relativistic limit of a microscopic interaction Hamiltonian involving Dirac quark fields. The evaluation of the decay amplitude can be performed by a diagrammatic technique for drawing quark lines. In this paper we use an alternative approach which consists in a mapping technique, the Fock-Tani formalism, in order to obtain an effective Hamiltonian starting from same microscopic interaction. An additional effect is manifest in this formalism associated to the extended nature of mesons: bound-state corrections. A corrected $3^P_0$ is obtained and applied, as an example, to $b_{1}\to\omega\pi$ and $a_{1}\to\rho\pi$ decays.Comment: 3 figures. To appear in Physical Review

Awareness of Dengue Fever among the Urban Youth in Colombo and its Suburbs, Sri Lanka in November 2014

The study was conducted to assess the knowledge regarding dengue infection that the laymen should have specifically in facing the consequences that comes after acquiring the infection. Dengue fever is a serious disease condition going on in Sri Lanka which is transmitted by carrier mosquitos Aedes aegypti and Aedes albopictus. According to the epidemiology unit of health ministry Sri Lanka, 57.82% out of 23,355 cases reported in the year 2014 by July are from the western province. In this research dengue awareness among young people in Colombo and its suburbs, especially after acquiring the infection is assessed, in November 2014.The objective of this study was to assess the dengue awareness and knowledge that the laymen should have especially in facing the events that comes after acquiring the infection, among the youth in Colombo and its suburbs. A descriptive study was done on 150 individuals residing in Colombo and its suburbs within the age range of 16-25 years using a simple online questionnaire, which was provided to the participants via a popular online social network. The collected data was analyzed using descriptive and analytical statistics. Though 90% of the participants knew common signs and symptoms of fever, only 48% knew the specific symptoms of dengue fever. 66% knew that the same set of drugs given for general body aches cannot be given in dengue fever. The only satisfactory result obtained was that 86% knew blood tests are done to detect dengue. Though only 16% of the participants had sufficient knowledge on contra indicated food, 66% knew the reasons for the contra indication, showing the overall knowledge in contraindicated food is poor. Only 32% had a clear idea on the popular indigenous practice of papaya leaf extracts as a treatment, that is there is only a possibility of curing dengue. 86% knew that some official should be informed when there is an infection going on in an area, other than hospitalization, while only 52% knew where and whom to inform. The study revealed that the urban youth in Sri Lanka lacks sufficient awareness and knowledge that they should have in facing the events that comes after acquiring the infection

Quantitative chemical tagging, stellar ages and the chemo-dynamical evolution of the Galactic disc

The early science results from the new generation of high-resolution stellar spectroscopic surveys, such as GALAH and the Gaia-ESO survey, will represent major milestones in the quest to chemically tag the Galaxy. Yet this technique to reconstruct dispersed coeval stellar groups has remained largely untested until recently. We build on previous work that developed an empirical chemical tagging probability function, which describes the likelihood that two field stars are conatal, that is, they were formed in the same cluster environment. In this work we perform the first ever blind chemical tagging experiment, i.e., tagging stars with no known or otherwise discernable associations, on a sample of 714 disc field stars with a number of high quality high resolution homogeneous metal abundance measurements. We present evidence that chemical tagging of field stars does identify coeval groups of stars, yet these groups may not represent distinct formation sites, e.g. as in dissolved open clusters, as previously thought. Our results point to several important conclusions, among them that group finding will be limited strictly to chemical abundance space, e.g. stellar ages, kinematics, colors, temperature and surface gravity do not enhance the detectability of groups. We also demonstrate that in addition to its role in probing the chemical enrichment and kinematic history of the Galactic disc, chemical tagging represents a powerful new stellar age determination technique.Comment: 12 pages, 9 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS

A nonextensive insight to the stellar initial mass function

the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by $q$-Weibulls that emerge within nonextensive statistical mechanics. As a result, we show that the Salpeter's slope of $\sim$2.35 is replaced when a $q$-Weibull distribution is used. Our results point out that the nonextensive entropic index $q$ represents a new approach for understanding the process of the star-forming and evolution of massive stars.Comment: 5 pages, 2 figures, Accepted to EP

Alterações na biomassa e atividade microbiana do solo devido ao uso de compostos orgânicos em um Argissolo Amarelo Eutrófico no Semiárido brasileiro.

A biomassa e respiração microbiana do solo são indicadores sensíveis das mudanças no solo. O objetivo deste trabalho foi comparar as alterações na biomassa e atividade microbiana do solo em um Argissolo Amarelo Eutrófico no Semiárido nordestino nos sistema de manejo orgânico, sistema de manejo convencional e caatinga. O estudo ocorreu no campo experimental de Bebedouro pertencente a EMBRAPA Semiárido - Petrolina-PE. Foi utilizado o delineamento em blocos casualizados com 6 tratamentos, correspondentes a área de sistema de manejo orgânico (SMO), submetido aos 5 compostos orgânicos e testemunha e as áreas de referencias compostas por área de sistema de manejo convencional (SMC) e área de caatinga hiperxerófila alterada (CAA). Foi avaliado os atributos do solo referente à RM, Cmic, qMic e qCO2. Os valores de RM, Cmic e qMic são semelhante para a área de CAA e SMO onde foi utilizado composto orgânico.Ref. 14562. Edição dos Resumos do VIII Congresso Brasileiro de Agroecologia, Porto Alegre, nov. 2013