An effective theory for jet propagation in dense QCD matter: jet broadening and medium-induced bremsstrahlung

Two effects, jet broadening and gluon bremsstrahlung induced by the propagation of a highly energetic quark in dense QCD matter, are reconsidered from effective theory point of view. We modify the standard Soft Collinear Effective Theory (SCET) Lagrangian to include Glauber modes, which are needed to implement the interactions between the medium and the collinear fields. We derive the Feynman rules for this Lagrangian and show that it is invariant under soft and collinear gauge transformations. We find that the newly constructed theory SCET$_{\rm G}$ recovers exactly the general result for the transverse momentum broadening of jets. In the limit where the radiated gluons are significantly less energetic than the parent quark, we obtain a jet energy-loss kernel identical to the one discussed in the reaction operator approach to parton propagation in matter. In the framework of SCET$_{\rm G}$ we present results for the fully-differential bremsstrahlung spectrum for both the incoherent and the Landau-Pomeranchunk-Migdal suppressed regimes beyond the soft-gluon approximation. Gauge invariance of the physics results is demonstrated explicitly by performing the calculations in both the light-cone and covariant $R_{\xi}$ gauges. We also show how the process-dependent medium-induced radiative corrections factorize from the jet production cross section on the example of the quark jets considered here.Comment: 52 pages, 15 pdf figures, as published in JHE

ε/ζ systems: their role in resistance, virulence, and their potential for antibiotic development

Cell death in bacteria can be triggered by activation of self-inflicted molecular mechanisms. Pathogenic bacteria often make use of suicide mechanisms in which the death of individual cells benefits survival of the population. Important elements for programmed cell death in bacteria are proteinaceous toxin–antitoxin systems. While the toxin generally resides dormant in the bacterial cytosol in complex with its antitoxin, conditions such as impaired de novo synthesis of the antitoxin or nutritional stress lead to antitoxin degradation and toxin activation. A widespread toxin–antitoxin family consists of the ε/ζ systems, which are distributed over plasmids and chromosomes of various pathogenic bacteria. In its inactive state, the bacteriotoxic ζ toxin protein is inhibited by its cognate antitoxin ε. Upon degradation of ε, the ζ toxin is released allowing this enzyme to poison bacterial cell wall synthesis, which eventually triggers autolysis. ε/ζ systems ensure stable plasmid inheritance by inducing death in plasmid-deprived offspring cells. In contrast, chromosomally encoded ε/ζ systems were reported to contribute to virulence of pathogenic bacteria, possibly by inducing autolysis in individual cells under stressful conditions. The capability of toxin–antitoxin systems to kill bacteria has made them potential targets for new therapeutic compounds. Toxin activation could be hijacked to induce suicide of bacteria. Likewise, the unique mechanism of ζ toxins could serve as template for new drugs. Contrarily, inhibition of virulence-associated ζ toxins might attenuate infections. Here we provide an overview of ε/ζ toxin–antitoxin family and its potential role in the development of new therapeutic approaches in microbial defense

Ensaio clínico comparando três modalidades de crioterapia em mulheres não grávidas Ensayo clínico comparando tres tipos de crioterapia en mujeres no embarazadas Clinical trial comparing three types of cryotherapy in non-pregnant women

O estudo teve como objetivo comparar três modalidades de crioterapia em mulheres saudáveis e não grávidas. Trata-se de um ensaio clínico randomizado, não controlado, com 32 alunas do curso de graduação de uma faculdade de enfermagem particular da cidade de São Paulo, divididas em três grupos (gelo água, gelo mole, gelo gel). Foram verificadas as temperaturas (axilar, coxa e das três bolsas de gelo) entre zero e vinte minutos. As temperaturas das bolsas foram: gelo mole de 9°C negativos a 2°C, gelo água de 0°C a 8°C e gelo gel de 11°C negativos a 2°C. Houve diferença significativa entre as médias das temperaturas da coxa com 10 minutos (p=0,007), 15 minutos (p=0,003) e 20 minutos (p=0,005). O gel foi mais eficiente no resfriamento comparado aos outros dois métodos. As três modalidades de crioterapia atingem a temperatura recomendada para analgesia e podem ser aplicadas em puérperas com dor perineal após o parto normal.<br>El estudio tuvo como objetivo comparar tres modalidades de crioterapia en mujeres saludables y no grávidas. Se trató de un ensayo clínico randomizado no controlado con 32 alumnas del curso de graduación de una facultad de enfermería particular de la ciudad de São Paulo (Brasil). Las alumnas fueron divididas en tres grupos (agua helada, hielo blando, gel helado). Fueron verificadas las temperaturas (axilar, del muslo y de las tres bolsas de hielo) entre cero y veinte minutos. Las temperaturas de las bolsas fueron: hielo blando, de -9°C a 2°C; agua helada, de 0°C a 8°C; gel helado, de -11°C a 2°C. Hubo diferencia significativa entre las medias de las temperaturas del muslo tomadas a los 10 minutos (p=0,007), 15 minutos (p=0,003) y 20 minutos (p=0,005). El gel fue más eficiente en el enfriamiento comparado con los otros dos métodos. Las tres modalidades de crioterapia alcanzan la temperatura recomendada para la analgesia y pueden ser aplicadas en mujeres con dolor perineal posparto.<br>The objective of the present study was to compare three methods of cryotherapy in healthy non-pregnant women. This is a randomized controlled clinical trial that was conducted by 32 undergraduates of a private nursing college in the city of Sao Paulo, divided into three groups (iced water, soft ice, ice gel). The temperatures were verified (axillary, thigh, of the three ice packs) between zero and twenty minutes. The temperatures of the packs were the following: soft ice, from negative 9°C to 2°C; iced water, from 0°C to 8°C; and ice gel from negative 11°C to 2°C. There was a significant difference between the average thigh temperature values at 10 minutes (p=0.007), 15 minutes (p=0.003) and 20 minutes (p=0.005). The gel was the most efficient cooling method. The three cryotherapy methods achieved the recommended temperature for analgesia and may be tested in women with perineal pain after childbirth