Gauge and Scheme Dependence of Mixing Matrix Renormalization

We revisit the issue of mixing matrix renormalization in theories that include Dirac or Majorana fermions. We show how a gauge-variant on-shell renormalized mixing matrix can be related to a manifestly gauge-independent one within a generalized ${\bar {\rm MS}}$ scheme of renormalization. This scheme-dependent relation is a consequence of the fact that in any scheme of renormalization, the gauge-dependent part of the mixing-matrix counterterm is ultra-violet safe and has a pure dispersive form. Employing the unitarity properties of the theory, we can successfully utilize the afore-mentioned scheme-dependent relation to preserve basic global or local symmetries of the bare Lagrangian through the entire process of renormalization. As an immediate application of our study, we derive the gauge-independent renormalization-group equations of mixing matrices in a minimal extension of the Standard Model with isosinglet neutrinos.Comment: 31 pages, LaTeX, uses axodraw.st

Movements of the Sciara del Fuoco

The Sciara del Fuoco (SdF) landslides that occurred at the end of December 2002 prompted researchers to install geodetic networks to monitor deformations related to potential new slope failures. With this aim, an integrated multiparametric monitoring system was designed and deployed. In particular, this complex monitoring system is composed of four single systems: an electronic distance measurement network, installed immediately after the landslide events, a realtime GPS network, a ground-based interferometric linear synthetic aperture radar (GB-InSAR), and an automated topographic monitoring system (named Theodolite Robotic Observatory of Stromboli, or THEODOROS); the three last systems provided a continuous monitoring of selected points or sectors of the SdF. Data acquired from different systems have been jointly analyzed to reach a better understanding of the SdF dynamics. Displacement data obtained from the topographic systems are compared with those obtained from GB-InSAR, and the results of the comparison are analyzed and discussed. Furthermore, in this chapter, an example of a warning system that can detect slope instability precursors on the SdF based on a statistical analysis of the data collected by the THEODOROS system is reported

Applying cointegration and error correction to measure trade linkages: maize prices in the United States and Mexico

The impact of U.S.-grown maize on Mexican markets is a subject of heated debate, and is complicated by limited substitution between white and yellow maize as well as regional price differences within Mexico. This article improves on previous analyses using a detailed data set of white maize prices reported weekly in 11 states across Mexico from 1998 through 2005. Using cointegration analysis and the error-correction model, we find that prices between the United States and Mexico do not share a common long-run relationship. Within Mexico, prices in Michoacán and Oaxaca are only weakly related with prices in neighboring states, whereas prices in Sinaloa and Jalisco exert considerable influence on prices elsewhere in Mexico. We conclude that, despite North American Free Trade Agreement (NAFTA), white maize prices in Mexico are determined by local conditions including particularly the degree of integration to other regions within Mexico. Copyright (c) 2008 International Association of Agricultural Economists.

Strong sex bias in elite control of paediatric HIV infection

Background: Reports of posttreatment control following antiretroviral therapy (ART) have prompted the question of how common immune control of HIV infection is in the absence of ART. In contrast to adult infection, where elite controllers have been very well characterized and constitute approximately 0.5% of infections, very few data exist to address this question in paediatric infection. Methods: We describe 11 ART-naive elite controllers from 10 cohorts of HIV-infected children being followed in South Africa, Brazil, Thailand, and Europe. Results: All but one of the elite controllers (91%) are females. The median age at which control of viraemia was achieved was 6.5 years. Five of these 11 (46%) children lost control of viraemia at a median age of 12.9 years. Children who maintained control of viraemia had significantly higher absolute CD4+ cell counts in the period of elite control than those who lost viraemic control. On the basis of data available from these cohorts, the prevalence of elite controllers in paediatric infection is estimated to be 5–10-fold lower than in adults. Conclusion: Although conclusions are limited by the study design, these data suggest that, whilst paediatric elite control can be achieved, compared with adult elite controllers, this occurs rarely, and takes some years after infection to achieve. Also, loss of immune control arises in a high proportion of children and often relatively rapidly. These findings are consistent with the more potent antiviral immune responses observed in adults and in females.</p

Strong sex bias in elite control of paediatric HIV infection

Background: Reports of post-treatment control following antiretroviral therapy (ART) have prompted the question of how common immune control of HIV infection is in the absence of ART. In contrast to adult infection, where elite controllers (EC) have been very well characterized and comprise approximately 0.5% of infections, very few data exist to address this question in paediatric infection. Methods: We describe 11 ART-naïve EC from 10 cohorts of HIV-infected children being followed in South Africa, Brazil, Thailand, and Europe, and describe their key clinical features. Results: All but one EC (91%) are female. The median age at which control of viraemia was achieved was 6.5yrs. Five of these 11 (46%) children lost control of viraemia at a median age 12.9yrs. Children who maintained control of viraemia had significantly higher absolute CD4 counts in the period of EC than those who lost viraemic control. Based on the data available from cross-sectional cohorts, the prevalence of EC in paediatric infection is estimated to be 5-10-fold lower than in adults. Conclusion: These data indicate that, whilst paediatric elite control can be achieved, compared to adult EC this occurs rarely, and takes some years after infection to achieve. Also, loss of immune control arises in a high proportion of children and often relatively rapidly. These findings are consistent with the more potent antiviral immune responses observed in adults and in females