738 research outputs found
O questionário no plenário do júri
Versa sobre a alteração no procedimento relativo aos processos da competência do Jurà na formulação e ordem dos quesitos
On First-Order Generalized Maxwell Equations
The generalized Maxwell equations including an additional scalar field are
considered in the first-order formalism. The gauge invariance of the Lagrangian
and equations is broken resulting the appearance of a scalar field. We find the
canonical and symmetrical Belinfante energy-momentum tensors. It is shown that
the traces of the energy-momentum tensors are not equal to zero and the
dilatation symmetry is broken in the theory considered. The matrix Hamiltonian
form of equations is obtained after the exclusion of the nondynamical
components. The canonical quantization is performed and the propagator of the
fields is found in the first-order formalism.Comment: 14 pages, corrections in Eq.(38),(39),(59
The role of smoking in social networks on smoking cessation and relapse among adults: A longitudinal study
Understanding the spread of smoking cessation and relapse within social networks may offer new approaches to further curb the smoking epidemic. Whether smoking behavior among social network members determines smoking cessation and relapse of adults however, is less known. For this study, longitudinal data of 4623 adults participating in the Dutch Longitudinal Internet Studies for the Social sciences (LISS) panel were collected in March 2013 with a follow-up in 2014. Logistic regression was used to examine the association between the proportion of smokers in social networks, and (1) smoking cessation (n = 762) and (2) smoking relapse (n = 1905). Analyses were adjusted for the size of the network, age, sex, and education. Respondents with the largest proportion of smokers in their social network were less likely to quit smoking (OR = 0.25; 95% CI = 0.11–0.66) and more likely to experience a relapse (6.08; 3.01–12.00). Smoking cessation and relapse were most strongly associated with the proportion of smokers among household members and friends. The proportion of smokers in family outside the household was not related to smoking cessation and smoking relapse. In conclusion, smoking behavior in social networks, especially among household members and friends, is strongly associated with smoking cessation and relapse. These findings further support the spread of smoking within social networks, and provide evidence for network-based interventions, particularly including household members and friends
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