Collective and fractal properties of pion jets in the four-velocity space at intermediate energies

Experimental results are presented for study of collective and fractal properties of soft pion jets in the space of relative four-dimensional velocities. Significant decreasing is obtained for mean square of second particle distances from jet axis for pion-proton interactions at initial energies $\sim 3$ GeV in comparison with hadron-nuclear collisions at close energies. The decreasing results in power dependence of distance variable on collision energy for range $\sim 2 - 4$ GeV. The observation allows us to estimate the low boundary of manifestation of color degree of freedom in pion jet production. Cluster dimension values were deduced for pion jets in various reactions. Fractional values of this dimension indicate on the manifestation of fractal-like properties by pion jets. Changing of mean kinetic energy of jet particles and fractal dimension with initial energy increasing is consistent with suggestion for presence of color degrees of freedom in pion jet production at intermediate energies.Comment: The conference "Physics of fundamental interactions". ITEP, Moscow, Russia. November 23 - 27, 200

On QCD Q2Q^2-evolution of Deuteron Structure Function F2D(xD,Q2)F_2^D(x_D,Q^2) for xD>1x_D>1

The deep-inelastic deuteron structure function (SF) $F_2^D(x_D,Q^2)$ in the covariant approach in light-cone variables is considered. The $x_D$ and $Q^2$-dependences of SF are calculated. The QCD analysis of generated data both for non-cumulative $x_D1$ ranges was performed. It was shown that $Q^2$-evolution of SF is valid for ranges $0.275<x_D<0.85$ and $1.1<x_D<1.4$ for the same value of QCD scale parameter ${\Lambda}$. It was found the $x_D$-dependence of SF for the ranges is essentially different.Comment: LaTeX, 10 pages, 2 Postscript figure

Efetividade de uma intervenção digital na diminuição da prática de binge drinking entre frequentadores de baladas

OBJECTIVE: To evaluate the effectiveness of a web-based intervention in reducing binge drinking among nightclub patrons after six months. METHODS: We carried out a website survey with probabilistic sample in 31 nightclubs in the city of São Paulo, Brazil, which originated a randomized controlled trial with 1,057 participants. Those classified as problem drinkers (n = 465) using the Alcohol Use Disorders Identification Test were randomized into two study groups – intervention and control. The web-based intervention consisted of exposing the participants to a normative feedback screen about their alcohol consumption, characterizing the risks associated with amount consumed, money spent on drinks, drinking and driving, risk classification of Alcohol Use Disorders Identification Test, and tips to reduce damage. RESULTS: There was a significant reduction in the practice of binge drinking in the week estimated at 38% among participants in the intervention group after six months (p &lt; 0.05). However, there was no significant reduction in the outcomes when we analyzed the intervention and control groups and at baseline and after sixth months, simultaneously. CONCLUSIONS: We cannot conclude that digital tools reduce the pattern of binge drinking among party goers in São Paulo. More studies are needed with this methodology because of its attractiveness to this type of group, given the privacy and speed that personalized information is transmitted.OBJETIVO: Avaliar, após seis meses, a efetividade de uma intervenção digital na diminuição da prática de binge drinking entre frequentadores de baladas. MÉTODOS: Foi realizado um inquérito de portal através de uma amostra probabilística em 31 baladas da cidade de São Paulo, a qual originou um ensaio controlado randomizado com 1.057 participantes. Aqueles classificados como uso problemático do álcool (n = 465) através do Alcohol Use Disorders Identification Test foram randomizados em dois grupos de estudo – intervenção e controle. A intervenção digital consistiu em expor os participantes a uma tela de feedback normativo sobre seu consumo de álcool, caracterizando os riscos associados à quantidade consumida, valores gastos com bebidas, beber e dirigir, classificação do risco do Alcohol Use Disorders Identification Test e dicas de redução de danos. RESULTADOS:Houve uma redução significativa da prática de binge drinking na semana estimada em 38% entre os participantes do grupo intervenção após seis meses (p &lt; 0,05). Porém, não houve redução significativa nos desfechos quando se analisam os grupos intervenção e controle e os tempos início e seis meses após, simultaneamente. CONCLUSÕES: Não se pode concluir que as ferramentas digitais reduzem o padrão de binge drinking nos frequentadores de baladas paulistanas. São necessários mais estudos com esta metodologia devido ao caráter atrativo para esse grupo, tendo em vista a privacidade e a rapidez que as informações personalizadas são transmitidas

Enabling comparison of UrQMD with Geant4 hadronic models

Geant4 has an abundant set of physics models that handle the diverse interaction of particles with matter across a wide energy range. However, there are also many well established reaction codes currently used in the same fields where Geant4 is applied. One such code is the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. In order to take advantage of the UrQMD code, we create a tool to enable comparisons among UrQMD and Geant4 hadronic models. This tool allows a user to process the output file of UrQMD through Geant4 toolkit, while at the same time, can choose among different Geant4 hadronic model generators. As an example, the UrQMD model is compared with the HARP-CDP experimental data and with the Binary and FRITIOF generators, in the framework of Geant4. It is shown that the UrQMD model can better reproduce charged pion production for p+Cu and Pb interactions at 3, 8 and 15 GeV/c, and is a good candidate for Geant4 hadronic models.Comment: 17 pages, 5 Figure

Electric polarizabilities of proton and neutron and the relativistic center-of-mass coordinate

We argue that the relativistic correction $\delta{\bf R}_{c.m.}$ to the center-of-mass vector can lead to the approximate equality of the proton and neutron electric polarizabilities in the quark model. The explicit form of $\delta{\bf R}_{c.m.}$ depends only on the non-relativistic potential between quarks. In particular, this correction is the same for the potential generated by Lorentz-vector and -scalar interactions.Comment: 8 pages, LaTeX, conclusion extende

Energy Storage in a Hamiltonian System in Partial Contact with a Heat Bath

To understand the mechanism allowing for the long-term storage of excess energy in proteins, we study a Hamiltonian system consisting of several coupled pendula in partial contact with a heat bath. It is found that energy storage is possible when the motion of each pendulum switches between oscillatory (vibrational) and rotational (phase-slip) modes. The storage time increases almost exponentially to the square root of the injected energy. The relevance of our mechanism to protein motors is discussed.Comment: 8 pages, 4 figures, to appear in J.Phys.Soc.Jp