Cu-Au type orderings in the staggered quadrupolar region of the fcc Blume Emery Griffiths model

The spin-1 Ising (BEG) model has been simulated using a cellular automaton (CA) algorithm improved from the Creutz cellular automaton (CCA) for a face-centered cubic (fcc) lattice. The ground state diagram ($k$, $d$) of the fcc BEG model has ferromagnetic ($F$), quadrupolar ($Q$) and staggered quadrupolar ($SQ$) ordering regions. The simulations have been made in the staggered quadrupolar region for the parameter values in the intervals $-24\leq d=D/J<0$ and $-3\leq k=K/J\leq 0$ . The phase diagrams on the ($kT_{C}/J$, $d$) and the ($kT_{C}/J$, $k$) planes have been obtained through $k=-3$ and $d=-4$ lines, respectively. The staggered quadrupolar ordering region separates into five ordering regions ($A_{3}B(a)$, $A_{3}B(f)$, $AB$ (type-I), $AB$(type-II) and $AB_{3}(f)$) which have the different stoichiometric Cu-Au type structures.Comment: 24 pages, 11 figure

Persons living with AIDS in nurses' social representations: analysis of central, contranormative and attitudinal elements

OBJECTIVES: to describe and analyze the centrality, the mute zone and the attitudes expressed in nurses' social representations of people with Human Immunodeficiency Virus. METHOD: the subjects were 30 nurses from a university hospital in Rio de Janeiro. The data was collected using a Likert scale. RESULTS: the data pointed to a process of representational change regarding Human Immunodeficiency Virus / Acquired Immunodeficiency Syndrome, with the assumption of a more positive attitude regarding living with this health issue. The hypothesis of the existence of a mute zone in the representation, comprising elements with a contranormative character, was strengthened. CONCLUSION: the influence of the dynamics of social normativity on how the social representations studied are expressed may contribute to a better understanding of its structuring process. It also helps in the analysis of possible gaps among the nurses' discourses and practices in relation to Human Immunodeficiency Virus / Acquired Immunodeficiency Syndrome.OBJETIVOS: describir y analizar la centralidad, la zona muda y las actitudes expresas en las representaciones sociales de enfermeros acerca de la persona con Virus de la Inmunodeficiencia Humana. MÉTODO: los sujetos fueron 30 enfermeros de un hospital universitario de Rio de Janeiro. Los datos fueron colectados utilizando escala tipo likert. RESULTADOS: indicaron un proceso de cambio representacional sobre el Virus de la Inmunodeficiencia Humana/Síndrome da Inmunodeficiencia Adquirida, con la Asunción de actitud más positiva sobre la convivencia con éste agravo. Fue reforzada hipótesis de existencia de zona muda en la representación compuesta por elementos de carácter contra normativo. CONCLUSIÓN: la influencia de la dinámica de normatividad social sobre el modo de expresión de las representaciones sociales estudiadas puede aportar para una mejor comprensión de su proceso de estructuración. Auxilia, también, en el análisis de eventuales desfases entre los discursos y las prácticas de los enfermeros con relación al Virus de la Inmunodeficiencia Humana/Síndrome da Inmunodeficiencia Adquirida.OBJETIVOS: descrever e analisar a centralidade, a zona muda e as atitudes expressas nas representações sociais de enfermeiros, acerca da pessoa com vírus da imunodeficiência humana. MÉTODO: os sujeitos foram 30 enfermeiros de um hospital universitário do Rio de Janeiro. Os dados foram coletados utilizando escala tipo Likert. RESULTADOS: os resultados indicaram um processo de mudança representacional sobre o vírus da imunodeficiência humana/síndrome da imunodeficiência adquirida, com a assunção de atitude mais positiva sobre a convivência com esse agravo. Foi reforçada a hipótese da existência de zona muda na representação composta por elementos de caráter contranormativo. CONCLUSÃO: a influência da dinâmica de normatividade social sobre o modo de expressão das representações sociais estudadas pode contribuir para melhor compreensão do seu processo de estruturação. Auxilia, também, na análise de eventuais defasagens entre os discursos e as práticas dos enfermeiros em relação ao vírus da imunodeficiência humana/síndrome da imunodeficiência adquirida

The micro-Raman spectroscopy, a useful tool to determine the degree of conversion of light-activated composite resins.

Light-activated composites are now among the most popular dental restorative materials. Nevertheless, concerns exist about the so-called depth of cure. Infrared spectroscopy (FTIR) has traditionally been used to quantify this problem by evaluating the degree of conversion of dental resins. However, Raman scattering provides an alternate method. This article describes the advantages and the limitations of micro-Raman spectroscopy, as compared to FTIR and other techniques, for calculating the local degree of conversion and the depth of cure of light-cured composites

Epitaxial growth of CdTe oriented thin films, infrared characterization and possible applications to photo-voltaic cells

The growth of CdTe oriented thin films by the ENSH method - i.e. Epitaxial Nucleation in Sub-microscopic Holes of an intermediate layer closely applied on a bulk single crystal — has been recently described. The CdTe films are generally difficult to detach from the bulk crystal. However free films are needed to study the infrared transmission in the spectral region of high absorption. To get them, the vitreous or amorphous thin intermediate layers are substituted by quite soluble an oriented NaCl layer grown from phase vapour on a (111) CdTe bulk crystal surface. The X-ray diffraction and Laue patterns show that the CdTe thin film grown on the NaCl intermediate layer is (111) oriented, and also the NaCl layer which covers the (111) CdTe bulk crystal surface. The far infrared transmission spectra obtained through the oriented CdTe films give directly the TO phonon frequency for q = 0 with accuracy.Des films minces orientés de CdTe, d'épaisseur comprise entre 0,1 et 10 μm, sont obtenus par épitaxie en phase vapeur. Le substrat est un monocristal de CdTe cubique dont la face (111), polie mécaniquement et décapée chimiquement, est préalablement recouverte d'une couche épitaxique mince de NaCl. Les films épitaxiques de CdTe obtenus sur ce substrat sont détachés par dissolution de NaCl dans l'eau. Les diffractogrammes de rayons X et les clichés de Laue montrent que les films de CdTe et de NaCl sont cristallisés dans le système cubique et sont orientés parallèlement aux plans (111). La densité de porteurs libres de chaque film de CdTe est calculée à partir de sa fréquence de plasma qui est donnée par son spectre de transmission infrarouge lointain. La mobilité des porteurs est calculée en fonction de la résistivité électrique du film et de sa densité de porteurs

Radiofrequency catheter ablation of atrial fibrillation: A cause of silent thromboembolism? Magnetic resonance imaging assessment of cerebral thromboembolism in patients undergoing ablation of atrial fibrillation

Background-Radiofrequency left atrial catheter ablation has become a routine procedure for treatment of atrial fibrillation. The aim of this study was to assess with preprocedural and postprocedural cerebral magnetic resonance imaging the thromboembolic risk, either silent or clinically manifest, in the context of atrial fibrillation ablation. The secondary end point was the identification of clinical or procedural parameters that correlate with cerebral embolism. Methods and Results-A total of 232 consecutive patients with paroxysmal or persistent atrial fibrillation who were candidates for radiofrequency left atrial catheter ablation were included in the study. Pulmonary vein isolation or pulmonary vein isolation plus linear lesions plus atrial defragmentation with the use of irrigated-tip ablation catheters was performed. All of the patients underwent preprocedural and postablation cerebral magnetic resonance imaging. A periprocedural symptomatic cerebrovascular accident occurred in 1 patient (0.4%). Postprocedural cerebral magnetic resonance imaging was positive for new embolic lesions in 33 patients (14%). No clinical parameters such as age, hypertension, diabetes mellitus, previous history of stroke, type of atrial fibrillation, and preablation antithrombotic treatment showed significant correlation with ischemic cerebral embolism. Procedural parameters such as activated clotting time value and, in particular, electric or pharmacological cardioversion to sinus rhythm correlated with an increased incidence of cerebral embolism. Cardioversion was also associated with an increased risk of 2.75 (95% confidence interval, 1.29 to 5.89; P=0.009). Conclusions-Radiofrequency left atrial catheter ablation carries a low risk of symptomatic cerebral ischemia but is associated with a substantial risk of silent cerebral ischemia detected on magnetic resonance imaging. Independent risk factors for cerebral thromboembolism are the level of activated clotting time and, in particular, the electric or pharmacological cardioversion to sinus rhythm during the procedure

A prospective, double-blind, placebo-controlled trial to establish a safe gluten threshold for patients with celiac disease

BACKGROUND: Treatment of celiac disease (CD) is based on the avoidance of gluten-containing food. However, it is not known whether trace amounts of gluten are harmful to treated patients. OBJECTIVE: The objective was to establish the safety threshold of prolonged exposure to trace amounts of gluten (ie, contaminating gluten). DESIGN: This was a multicenter, double-blind, placebo-controlled, randomized trial in 49 adults with biopsy-proven CD who were being treated with a gluten-free diet (GFD) for > or = 2 y. The back ground daily gluten intake was mainained at < 5 mg. After a baseline evaluation (t0), patients were assigned to ingest daily for 90 d a capsule containing 0. 10, or 50 mg gluten. Clinical, serologica, and histologic evaluations of the small intestine were performed at t0 and after the gluten microhallenge (t1). RESULTS: At t0, the median villous height/crypt depth (Vh/Cd) in the small-intestinal mucosa was significantly lower and the intraepithelial lymphocyte (IEL) count (x 100 enterocytes) significantly higher in the CD patients (Vh/Cd: 2.20; 95% CI: 2. 11, 2.89; IEL: 27; 95% CI: 23, 34) than in 20 non -CD control subjects (Vh/Cd: 2.87, 95% CI: 2.50, 3.09; IEL: 22; 95% CI: 18, 24). One patient (challenged with 10 mg gluten) developed a clinical relapse. At t(1), the percentate change in Vh/Cd was 9% CI: 3%, 15%) in the placebo group (n= 13), -1% (-18%, 68%) in the 10 mg group (n = 13), and -20% (-22%, -13%) in the 50-mg group (n = 13). No significant differences in the IEL count were found between the 3 groups. CONCLUSINS: The ingestion of contaminating gluten should be kept lower then 50 mg/d in the treatment of CD