Cosmological evolution of semilocal string networks.

Semilocal strings-a particular limit of electroweak strings-are an interesting example of a stable non-topological defect whose properties resemble those of their topological cousins, the Abrikosov-Nielsen-Olesen vortices. There is, however, one important difference: a network of semilocal strings will contain segments. These are 'dumbbells' whose ends behave almost like global monopoles that are strongly attracted to one another. While closed loops of string will eventually shrink and disappear, the segments can either shrink or grow, and a cosmological network of semilocal strings will reach a scaling regime. We discuss attempts to find a 'thermodynamic' description of the cosmological evolution and scaling of a network of semilocal strings, by analogy with well-known descriptions for cosmic strings and for monopoles. We propose a model for the time evolution of an overall length scale and typical velocity for the network as well as for its segments, and some supporting (preliminary) numerical evidence. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

The status of varying constants: a review of the physics, searches and implications.

The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete-if not incorrect-and that new physics is out there, waiting to be discovered. A key task for the next generation of laboratory and astrophysical facilities is to search for, identify and ultimately characterize this new physics. Here we highlight recent developments in tests of the stability of nature's fundamental couplings, which provide a direct handle on new physics: a detection of variations will be revolutionary, but even improved null results provide competitive constraints on a range of cosmological and particle physics paradigms. A joint analysis of all currently available data shows a preference for variations of α and µ at about the two-sigma level, but inconsistencies between different sub-sets (likely due to hidden systematics) suggest that these statistical preferences need to be taken with caution. On the other hand, these measurements strongly constrain Weak Equivalence Principle violations. Plans and forecasts for forthcoming studies with facilities such as ALMA, ESPRESSO and the ELT, which should clarify these issues, are also discussed, and synergies with other probes are briefly highlighted. The goal is to show how a new generation of precision consistency tests of the standard paradigm will soon become possible.

General purpose graphics-processing-unit implementation of cosmological domain wall network evolution.

Topological defects unavoidably form at symmetry breaking phase transitions in the early universe. To probe the parameter space of theoretical models and set tighter experimental constraints (exploiting the recent advances in astrophysical observations), one requires more and more demanding simulations, and therefore more hardware resources and computation time. Improving the speed and efficiency of existing codes is essential. Here we present a general purpose graphics-processing-unit implementation of the canonical Press-Ryden-Spergel algorithm for the evolution of cosmological domain wall networks. This is ported to the Open Computing Language standard, and as a consequence significant speedups are achieved both in two-dimensional (2D) and 3D simulations.

The endocannabinoid system--back to the scene of cardiometabolic risk factors control?

This review examines the impact of the endocannabinoid signaling system on metabolic and cardiovascular health and the new therapeutic strategies that selectively target dysfunctional endocannabinoid action in peripheral tissues, without causing the undesirable central nervous system effects that occurred with the first-generation of CB1 receptor blockers. We first review the components of the endocannabinoid system and the enzymes that synthesize and degrade the endocannabinoids, the critical role of the system in the homeostasis of energy balance, and its hedonic aspects related to the incentive and motivational value of food. Second, we describe the central and peripheral actions of the endocannabinoid system and its interactions with other biological modulators, such as ghrelin and leptin. Third, we summarize data from human clinical trials with the CB1 inverse agonist rimonabant, showing that the drug, although effective in increasing weight loss with accompanying improvements in the metabolic profile of the participants in the RIO (Rimonabant In Obesity) trials, was withdrawn from the market because of the risk of serious adverse events. Finally, we describe: 1) the development of new selective peripheral blockers that interrupt endocannabinoid action selectively in peripheral tissues and that have been suggested as an alternative approach to treat the metabolic consequences of obesity and related diseases, without undesirable central nervous system effects, and 2) the potential for inhibition of enzymes of synthesis, as well as the possible role of endocannabinoid congeners, with opposing effects as compared to CB1 receptor agonists, in the control of metabolic disorders.

Study of cutaneous cell carcinomas ex vivo using ultrasound biomicroscopic images.

BACKGROUND: The ultrasound biomicroscopy (UBM) technique generates high-resolution echographic images using acoustic frequencies between 20 and 200 MHz. In dermatology, it enables non-invasive visualization of cutaneous structures. In this sense, several studies are being conducted for the measurement of cutaneous tumor sizes and for the evaluation of their response to therapeutic procedures. The present work was conducted to analyze the ability of UBM to identify diverse histological structures associated with cutaneous carcinomas ex vivo regarding the evaluation of the technique as a diagnostic tool that could, eventually, improve the patient's healthcare protocol. METHODS: Ex vivo human tissue samples, corresponding to basal cell carcinoma and squamous cell carcinoma cases, were studied. The ultrasonic system operated with a center frequency of 45MHz and the histological structures were identified by comparison with the light microscopy images. RESULTS: The histological components present in the tumors were identified by variations in the echogenicity level for several of the studied cases and particular characteristics were observed for the different tumor types. CONCLUSION: The possibility of differentiating the histological components associated with cutaneous carcinomas indicates the potential use of UBM for diagnostic applications. However, a larger number of specimens must be studied.

Psoriasis affects individuals of African descent and white Brazilians similarly.

INTRODUCTION: Cultural, socio-demographic and environmental factors such as tropical climate and exposure to sun could have an impact on the incidence or clinical course of psoriasis. Here we describe the main clinical aspects of psoriasis in Brazilian patients and also investigate whether any particular feature can distinguish the disease occurring in Brazil from that occurring in other countries. MATERIAL AND METHODS: We recorded the clinical features of 151 psoriasis patients seen in a Brazilian public dermatological care unit between 2006 and 2008. RESULTS: Males and females were similarly affected. The reported races were as follows: whites, 47 cases (41.6%), interracial individuals (mixed race), 42 cases (37.2%) and blacks, 24 cases (21.2%). Chronic plaque-type psoriasis was the most prevalent clinical form (110 cases, 72.8%) followed by palm and sole involvement (21 cases, 13.9%). CONCLUSIONS: We demonstrated that psoriasis in these Brazilian subjects was similar to that observed in subjects from other countries, but interracial and black populations were affected as much as whites. Considering the high rate of interracial populations among Brazilians we cannot exclude the possibility that Afro-descendants may have inherited Caucasian genes associated with psoriasis. Poor socio-economic conditions of Afro-descendants can limit their possibilities of receiving adequate treatments, impairing their health-related quality of life.

Unified model for vortex-string network evolution.

We describe and numerically test the velocity-dependent one-scale string evolution model, a simple analytic approach describing a string network with the averaged correlation length and velocity. We show that it accurately reproduces the large-scale behavior (in particular the scaling laws) of numerical simulations of both Goto-Nambu and field theory string networks. We explicitly demonstrate the relation between the high-energy physics approach and the damped and nonrelativistic limits which are relevant for condensed matter physics. We also reproduce experimental results in this context and show that the vortex-string density is significantly reduced by loop production, an effect not included in the usual "coarse-grained" approach.

Topological defects in contracting universes.

We study the behavior and consequences of cosmic string networks in contracting universes. They approximately behave during the collapse phase as radiation fluids. Scaling solutions describing this are derived and tested against high-resolution numerical simulations. A string network in a contracting universe, together with the gravitational radiation it generates, can affect the dynamics of the universe both locally and globally and be an important source of radiation, entropy, and inhomogeneity. We discuss possible implications for bouncing and cyclic models.

Estudio experimental de técnicas de fijación testicular / Experimental study on orchipexy

La fijación testicular se realiza para prevenir la torsión del órgano y en la corrección de la criptorquidia.Se han utilizado para ello diversas técnicas,persistiendo discordancia respecto a cúal es la mejor,con menor daño testicular.Este estudio se realizó para comparar la fijación y el grado de lesión testicular con distintas técnicas quirúrgicas,utilizando dos tipos de sutura.Cuarenta ratas adultas de la raza Wistar,anestesiadas con eter etílico se sometieron a la incisión del escroto y exposición de ambos testículos.Se definieron en forma aleatoria cuatro grupos:grupo 1(n=10)fijación con un punto único,grupo 2(n=10)al que se fijó el testículo con dos puntos,grupo 3(n=10)en el que el testículo se fijó con tres puntos.En la mitad de los animales fue utilizado Vicryl 5-0,y en le resto se utilizó Mersilene 5-0,en el grupo 4 (n=10)el testículo se colocó en la bolsa sabdártica sin puntos de sutura.El testículo contralateral no tratado fue utilizado como control.Todos los animales se sacrificaron a los 30 días,evaluándose el grado de fijación macroscópica,eltamaño del testículo,y las alteraciones microscópicas del mismo.Todos los animales completaron el período previsto de observación.Se observó una diferencia significativa de la fijación entre los grupos(p<0,0038):los animales del grupo 1 presentaron una fijación menor respecto a los otrso grupos.Entre los grupos 2,3 y 4 no se observó una diferencia significativa en la fijación,tampoco hubo diferencia entre los animales del mismo grupo suturados con vicryl o mersilene.No se observaron alteraciones inflamatorias testiculares estadísticamente significativas entre los grupos ni entre los animales del mismo grupo fijados con las dos suturas.La fijación testicular con 2 o 3 puntos en la bolsa subdártica es superios a la realizada con un punto único.Esta última provoca alteraciones semejantes a las encontradas con las otras técnicas,que produce significativamente menor fijación

Estudio experimental de técnicas de fijación testicular / Experimental study on orchipexy

La fijación testicular se realiza para prevenir la torsión del órgano y en la corrección de la criptorquidia.Se han utilizado para ello diversas técnicas,persistiendo discordancia respecto a cúal es la mejor,con menor daño testicular.Este estudio se realizó para comparar la fijación y el grado de lesión testicular con distintas técnicas quirúrgicas,utilizando dos tipos de sutura.Cuarenta ratas adultas de la raza Wistar,anestesiadas con eter etílico se sometieron a la incisión del escroto y exposición de ambos testículos.Se definieron en forma aleatoria cuatro grupos:grupo 1(n=10)fijación con un punto único,grupo 2(n=10)al que se fijó el testículo con dos puntos,grupo 3(n=10)en el que el testículo se fijó con tres puntos.En la mitad de los animales fue utilizado Vicryl 5-0,y en le resto se utilizó Mersilene 5-0,en el grupo 4 (n=10)el testículo se colocó en la bolsa sabdártica sin puntos de sutura.El testículo contralateral no tratado fue utilizado como control.Todos los animales se sacrificaron a los 30 días,evaluándose el grado de fijación macroscópica,eltamaño del testículo,y las alteraciones microscópicas del mismo.Todos los animales completaron el período previsto de observación.Se observó una diferencia significativa de la fijación entre los grupos(p<0,0038):los animales del grupo 1 presentaron una fijación menor respecto a los otrso grupos.Entre los grupos 2,3 y 4 no se observó una diferencia significativa en la fijación,tampoco hubo diferencia entre los animales del mismo grupo suturados con vicryl o mersilene.No se observaron alteraciones inflamatorias testiculares estadísticamente significativas entre los grupos ni entre los animales del mismo grupo fijados con las dos suturas.La fijación testicular con 2 o 3 puntos en la bolsa subdártica es superios a la realizada con un punto único.Esta última provoca alteraciones semejantes a las encontradas con las otras técnicas,que produce significativamente menor fijación