Frequency of extreme rainfall events in Southern Brazil modulated by interannual and interdecadal variability

The frequency of extreme rainfall events in Southern Brazil is impacted by Ell Nino - Southern Oscillation (ENSO) episodes, especially in austral spring. There are two areas in which this impact is more significant: one is on the coast, where extreme events are more frequent during El Nino (EN) and the other one extends inland, where extreme events increase during EN and decrease during La Nina (LN). Atmospheric circulation patterns associated with severe rainfall in those areas are similar (opposite) to anomalous patterns characteristic of EN (LN) episodes, indicating why increase (decrease) of extreme events in EN (LN) episodes is favoured. The most recurrent precipitation patterns during extreme rainfall events in each of these areas are disclosed by Principal Component Analysis (PCA) and evidence the separation between extreme events in these areas: a severe precipitation event generally does not occur simultaneously in the coast and inland, although they may Occur inland and in the coastal region in sequence. Although EN predominantly enhances extreme rainfall, there are EN years in which fewer severe events occur than the average of neutral years, and also the enhancement of extreme rainfall is not uniform for different EN episodes, because the interdecadal non-ENSO variability also modulates significantly the frequency of extreme events in Southern Brazil. The inland region, which is more affected, shows increase (decrease) of extreme rainfall in association with the negative (positive) phase of the Atlantic Multidecadal Variability, with the negative (positive) phase of the Pacific Multidecadal Variability and with the positive (negative) phase of the Pacific Interdecadal Variability. Copyright (C) 2008 Royal Meteorological Society

Influence of calcination temperature on the morphology and magnetic properties of Ni-Zn ferrite applied as an electromagnetic energy absorber

An evaluation was made of the influence of calcination temperatures on the structure, morphology and eletromagnetic properties of Ni-Zn ferrite powders. To this end, Ni(0.5)Zn(0.5)Fe(2)O(4) ferrite powders were prepared by combustion reaction and calcined at temperatures of 800, 1000 and 1200 degrees C/2 h. The resulting powders were characterized by XRD, SEM and reflectivity measurements in the frequency bands of 8-12 GHz. The results demonstrated that raising the calcination temperature increased the particle sizes of the powders of all the systems in question, improving the reflectivity of the materials. (C) 2008 Elsevier B.V. All rights reserved.

A Comparative Study of the Frequency of Antibody and Titers Against Human Herpesvirus 8 Latent and Lytic Antigens in ""At-Risk"" Individuals and Among Patients With Kaposi`s Sarcoma

Differences in the prevalence of human herpesvirus 8 (HHV-8) and Kaposi`s sarcoma (KS) have been described, depending on the study population and their geographic origin. A cross-sectional study aimed at detecting the frequency and titers of antibodies against HHV-8 latent and lytic antigens in serum samples from individuals with different risk-factors for HHV-8 infection, as well as predictive marker identification in patients with KS, was conducted. Serum samples were collected from seven groups of individuals: 75 patients with AIDS-KS, 5 with classic KS, 16 with African KS, 495 with HIV/AIDS, 805 patients with chronic kidney disease, 683 handicapped individuals, and 757 health care workers. Samples were evaluated for the presence and titers of HHV-8-specific antibodies to latent and lytic antigens using ""in house"" immunofluorescence assays. The results were analyzed by the Chi-square, Fisher`s exact test, Kruskal-Wallis and/or Mann-Whitney U-tests. The frequencies of HHV-8 antibodies were as follows: 87.5-100% in patients with KS, 20.4% in patients with HIV/AIDS, 18% in patients with chronic kidney disease, 1.6% in handicapped individuals, and 1.1% in health care workers. A greater number of samples were antibody positive to lytic antigens. Elevated titers of antibodies to latent and lytic antigens, mostly among patients with KS, were detected. Using established serological assays, different ""at-risk"" populations for HHV-8 infection/disease were detected in this geographic area, confirming HIV/AIDS and identifying patients with chronic kidney disease as high-risk groups. It is suggested that a longitudinal evaluation of antibody titers in patients with chronic kidney disease be undertaken to confirm their predictive value in the development of KS. J. Med. Virol. 81: 1292-1297, 2009. (C) 2009 Wiley-Liss, Inc.

High frequency of immature dendritic cells and altered in situ production of interleukin-4 and tumor necrosis factor-alpha in lung cancer

Introduction Antigen-presenting cells, like dendritic cells (DCs) and macrophages, play a significant role in the induction of an immune response and an imbalance in the proportion of macrophages, immature and mature DCs within the tumor could affect significantly the immune response to cancer. DCs and macrophages can differentiate from monocytes, depending on the milieu, where cytokines, like interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce DC differentiation and tumor necrosis factor (TNF)-alpha induce DC maturation. Thus, the aim of this work was to analyze by immunohistochemistry the presence of DCs (S100+ or CD1a+), macrophages (CD68+), IL-4 and TNF-alpha within the microenvironment of primary lung carcinomas. Results Higher frequencies of both immature DCs and macrophages were detected in the tumor-affected lung, when compared to the non-affected lung. Also, TNF-alpha-positive cells were more frequent, while IL-4-positive cells were less frequent in neoplastic tissues. This decreased frequency of mature DCs within the tumor was further confirmed by the lower frequency of CD14-CD80+ cells in cell suspensions obtained from the same lung tissues analyzed by flow cytometry. Conclusion These data are discussed and interpreted as the result of an environment that does not oppose monocyte differentiation into DCs, but that could impair DC maturation, thus affecting the induction of effective immune responses against the tumor.

Reduced frequency of CD4(+)CD25(HIGH)FOXP3(+) cells and diminished FOXP3 expression in patients with Common Variable Immunodeficiency: A link to autoimmunity?

Common Variable Immunodeficiency (CVID) is a primary immunodeficiency disease characterized by defective immunoglobulin production and often associated with autoimmunity. We used flow cytometry to analyze CD4(+)CD25(HIGH)FOXP3(+) T regulatory (Treg) cells and ask whether perturbations in their frequency in peripheral blood could underlie the high incidence of autoimmune disorders in CVID patients. In this study, we report for the first time that CVID patients with autoimmune disease have a significantly reduced frequency of CD4(+)CD25(HIGH)FOXP3(+) cells in their peripheral blood accompanied by a decreased intensity of FOXP3 expression. Notably, although CVID patients in whom autoimmunity was not diagnosed had a reduced frequency of CD4(+)CD25(HIGH)FOXP3(+) cells, FOXP3 expression levels did not differ from those in healthy controls. In conclusion, these data suggest compromised homeostasis of CD4(+)CD25(HIGH)FOXP3(+) cells in a subset of CVID patients with autoimmunity, and may implicate Treg cells in pathological mechanisms of CVID. (C) 2009 Elsevier Inc. All rights reserved.

Stability of periodic optical solitons for a nonlinear Schrodinger system

This paper is concerned with the existence and nonlinear stability of periodic travelling-wave solutions for a nonlinear Schrodinger-type system arising in nonlinear optics. We show the existence of smooth curves of periodic solutions depending on the dnoidal-type functions. We prove stability results by perturbations having the same minimal wavelength, and instability behaviour by perturbations of two or more times the minima period. We also establish global well posedness for our system by using Bourgain`s approach.

Stability of periodic travelling shallow-water waves determined by Newton`s equation

We study the existence and stability of periodic travelling-wave solutions for generalized Benjamin-Bona-Mahony and Camassa-Holm equations. To prove orbital stability, we use the abstract results of Grillakis-Shatah-Strauss and the Floquet theory for periodic eigenvalue problems.

An investigation of the activation process of high temperature shift catalyst

The aim of this work is to address the activation process of a high temperature shift (HTS) catalyst, composed of Fe2O3/Cr2O3/CuO, by analyzing it before activation (HTS-V) and after activation (HTS-A) using complementary characterization techniques. The textural and morphological characterizations were done by transmission electron rnicroscopy (TEM) and nitrogen physisorption at 77 K; crystallographic structure was confirmed by X-ray diffraction (XRD); electronic structure was analyzed by X-ray absorption spectroscopy (XAS) and the chemical composition of the catalyst`s surface was obtained by X-ray photoelectron spectroscopy (XPS). The investigation pointed out that the HTS-V catalyst presents good textural and morphological properties, which are not deeply affected by the activation process (sample HTS-A). The iron oxide phase in the HTS-V catalyst is hematite whereas in HTS-A catalyst is magnetite with Fe2+/Fe3+ ratio close to the expected value (0.5). For both samples, the Cr ions seem to be incorporated in the iron oxide lattice with higher concentration at particle surface. In the HTS-V catalyst, the Cu ions have oxidation number II and occupy in average distorted octahedral sites; after the activation, the Cu ions are partially reduced, suggesting that the reduction of the Cu species is complex. (C) 2007 Elsevier B.V. All rights reserved.