New Chiral Fermions, a New Gauge Interaction, Dirac Neutrinos, and Dark Matter

We propose that all light fermionic degrees of freedom, including the Standard Model (SM) fermions and all possible light beyond-the-standard-model fields, are chiral with respect to some spontaneously broken abelian gauge symmetry. Hypercharge, for example, plays this role for the SM fermions. We introduce a new symmetry, $U(1)_{\nu}$, for all new light fermionic states. Anomaly cancellations mandate the existence of several new fermion fields with nontrivial $U(1)_{\nu}$ charges. We develop a concrete model of this type, for which we show that (i) some fermions remain massless after $U(1)_{\nu}$ breaking -- similar to SM neutrinos -- and (ii) accidental global symmetries translate into stable massive particles -- similar to SM protons. These ingredients provide a solution to the dark matter and neutrino mass puzzles assuming one also postulates the existence of heavy degrees of freedom that act as "mediators" between the two sectors. The neutrino mass mechanism described here leads to parametrically small Dirac neutrino masses, and the model also requires the existence of at least four Dirac sterile neutrinos. Finally, we describe a general technique to write down chiral-fermions-only models that are at least anomaly-free under a $U(1)$ gauge symmetry

SAMBA: Stochastic Analytical Model with a Bayesian Approach

We develop and estimate a DSGE model for the Brazilian economy, to be used as part of the macroeconomic modeling framework at the Central Bank of Brazil. The model combines the building blocks of standard DSGE models (e.g., price and wage rigidities and adjustment costs) with the following features that better describe the Brazilian economy: (i) a fiscal authority pursuing an explicit target for the primary surplus; (ii) administered or regulated prices as part of consumer prices; (iii) external finance for imports, amplifying the effects of changes in external financial conditions on the economy; and (iv) imported goods used in the production function of differentiated goods. It also includes the presence of financially constrained households. We estimate the model with Bayesian techniques, using data starting in 1999, when inflation targeting was implemented. Model evaluation, based on impulse response functions, moment conditions, variance error decomposition and initial forecasting exercises, suggests that the model can be a useful tool for policy analysis and forecasting.

Prevalência de toxoplasmose em gatos dos Estados de São Paulo e Paraná

Serum samples of 191 cats from 3 cities of São Paulo State and 1 of Paraná State were tested by indirect immunofluorescent assay (IFAT) for anti-toxoplasma IgG antibodies. Of the total, 56 (29.3%) were pure breed cats and 135 (70.7%) were mongrel cats, 88 (46.1%) and 103 (53.9%) were females and males, respectively, with ages ranging from two months to eighteen years. 37 (19.4%) samples reacted positively to IFAT, with 1/16 (n=10; 27.0%), 1/64 (n=18; 48.6%) and 1/256 (n=9; 24.3%) titres. No significant correlation was observed between sex, breed, origin or age (p >; 0.05), however the infection rate was higher in old animals, with 13.2% in animals between two months and three years old, 23.5% between three and six years old, 17.6% between six and nine years old, 25% between nine and 12 years old, 20% between 12 and 15 years old and 50% between 15 and 18 years old.Foram avaliados pela reação de imunofluorescência indireta (RIFI) para detecção de anticorpos-IgG anti-Toxoplasma, soros de 191 gatos de 3 diferentes municípios do Estado de São Paulo e um município do Estado do Paraná, enviados ao Serviço de Diagnóstico de Zoonoses, da Faculdade de Medicina Veterinária e Zootecnia, UNESP, Campus de Botucatu. Destes animais, 56 (29,3%) possuíam raça definida e 135 (70,7%) sem raça definida (SRD), sendo 88 (46,1%) fêmeas e 103 (53,9%) machos, com idades variando de dois meses a dezoito anos. Obtiveram-se 37 (19,4%) animais reagentes à RIFI, com títulos de 1/16 (n = 10;27,0%), 1/64 (n = 18;48,6%) e 1/256 (n = 9;24,3%). Não houve associação significativa entre sexo, raça, procedência ou idade (p >; 0,05), entretanto, a taxa de infecção foi maior em animais mais velhos, com 13,2% dos animais entre dois meses e três anos de idade, 23,5% entre três e seis anos, 17,6% entre seis e nove anos, 25% entre nove e doze anos, 20% entre doze e quinze anos e 50% entre quinze e dezoito anos de idade

Prevalência de toxoplasmose em gatos dos Estados de São Paulo e Paraná

Foram avaliados pela reação de imunofluorescência indireta (RIFI) para detecção de anticorpos-IgG anti-Toxoplasma, soros de 191 gatos de 3 diferentes municípios do Estado de São Paulo e um município do Estado do Paraná, enviados ao Serviço de Diagnóstico de Zoonoses, da Faculdade de Medicina Veterinária e Zootecnia, UNESP, Campus de Botucatu. Destes animais, 56 (29,3%) possuíam raça definida e 135 (70,7%) sem raça definida (SRD), sendo 88 (46,1%) fêmeas e 103 (53,9%) machos, com idades variando de dois meses a dezoito anos. Obtiveram-se 37 (19,4%) animais reagentes à RIFI, com títulos de 1/16 (n = 10;27,0%), 1/64 (n = 18;48,6%) e 1/256 (n = 9;24,3%). Não houve associação significativa entre sexo, raça, procedência ou idade (p >; 0,05), entretanto, a taxa de infecção foi maior em animais mais velhos, com 13,2% dos animais entre dois meses e três anos de idade, 23,5% entre três e seis anos, 17,6% entre seis e nove anos, 25% entre nove e doze anos, 20% entre doze e quinze anos e 50% entre quinze e dezoito anos de idade

Evaluation of information systems focusing on user satisfaction: a study developed in the metropolitan region of Belo Horizonte – MG

This paper presents the results of a study developed in organizations located in the metropolitan region of Belo Horizonte, in Minas Gerais state. The research aimed to evaluate: (a) the information systems (IS) used by the organizations; (b) the information provided by the IS; and (c) the satisfaction of the IS’s users. The study was based on a questionnaire applied to 335 users of several IS’s at 161 different companies. The following techniques were used to analyze the data: (i) descriptive statistics; (ii) exploratory factor analysis; (iii) Kolmogorov- -Smirnov test; (iv) analysis of variance (ANOVA); and (v) the Tukey test. It was found that the users evaluated every analyzed attribute of the IS’s, and the information provided by them, as “good”. Moreover, the users most satisfied with the IS usually responded positively to the attributes evaluated

Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

In order to analyze the effect of the growth direction on dendrite arm spacing (λ1) and microhardness (HV) during horizontal directional solidification (HDS), experiments were carried out with the Al-3wt.%Cu-5.5wt.%Si alloy and the results compared with others from the literature elaborated for upward directional solidification (UDS). For this purpose, a water-cooled directional solidification experimental device was developed, and the alloy investigated was solidified under unsteady-state heat flow conditions. Thermal parameters such as growth rate (VL) and cooling rate (TR) were determined experimentally and correlations among VL, TR, λ1 and HV has been performed. It is observed that experimental power laws characterize λ1 with a function of VL and TRgiven by: λ1=constant(VL)-1.1 and λ1=constant(TR)-0.55. The horizontal solidification direction has not affected the power growth law of λ1 found for the upward solidification. However, higher values of λ1 have been observed when the solidification is developed in the horizontal direction. The interrelation of HV as function of VL, TR and λ1 has been represented by power and Hall-Petch laws. A comparison with the Al-3wt.%Cu alloy from literature was also performed and the results show the Si element affecting significativaly the HV values