Quasinormal frequencies of asymptotically flat two-dimensional black holes

We discuss whether the minimally coupled massless Klein-Gordon and Dirac fields have well defined quasinormal modes in single horizon, asymptotically flat two-dimensional black holes. To get the result we solve the equations of motion in the massless limit and we also calculate the effective potentials of Schrodinger type equations. Furthermore we calculate exactly the quasinormal frequencies of the Dirac field propagating in the two-dimensional uncharged Witten black hole. We compare our results on its quasinormal frequencies with other already published.Comment: 12 pages. Accepted for publication in Gen. Rel. and Gra

Synthesis, thermal behavior, and aggregation in aqueous solution of poly(methyl methacrylate)-b-poly(2-hydroxyethyl methacrylate)

Indexación: ScieloABSTRACT Amphiphilic block copolymers of poly(methyl methacrylate) PMMA and poly(2-hidroxyethyl methacrylate) PHEMA were synthesized by a two-step atom transfer radical polymerization (ATRP). Copolymers with various degrees of polymerization and different relative block sizes were obtained. The structure of the resulting polymers have been characterized and verified by FT-IR and 1H-NMR, molecular weight were determined by size exclusion chromatography analyses. The thermal properties of these polymers were investigated by differential scanning calorimetry DSC and thermogravimetric analysis TGA. The glass transition temperature of mono halogenated PMMA increases from 116 °C to 123 °C with increasing molecular weight, whereas the glass transition temperature of block copolymers depends slightly on polymer structure. The derivatives of TGA curves indicate that thermal degradation occurs in one stage. The self-assembly of PMMA-b-PHEMA in aqueous solution have been investigated by fluorescence probing methods. The critical micelle concentrations are in the range 10-6 - 10-7 M. The micropolarity sensed by pyrene is higher than in aggregates formed by block copolymers based on polystyrene. Keywords: Block copolymers, glass transition temperature, thermogravimetric analysis, critical micelle concentration, fluorescence probing methods

High Resolution Spectrometry of Leaf and Canopy Chemistry for Biochemical Cycling

High-resolution laboratory spectrophotometer and Airborne Imaging Spectrometer (AIS) data were used to analyze forest leaf and canopy chemistry. Fundamental stretching frequencies of organic bonds in the visible, near infrared and short-wave infrared are indicative of concentrations and total content of nitrogen, phosphorous, starch and sugar. Laboratory spectrophotometer measurements showed very strong negative correlations with nitrogen (measured using wet chemistry) in the visible wavelengths. Strong correlations with green wet canopy weight in the atmospheric water absorption windows were observed in the AIS data. A fairly strong negative correlation between the AIS data at 1500 nm and total nitrogen and nitrogen concentration was evident. This relationship corresponds very closely to protein absorption features near 1500 nm

Religion and Attitudes toward Same-Sex Marriage among U.S. Latinos

Objectives. This study examines links between multiple aspects of religious involvement and attitudes toward same-sex marriage among U.S. Latinos. The primary focus is on variations by affiliation and participation, but the possible mediating roles of biblical beliefs, clergy cues, and the role of religion in shaping political views are also considered. Methods. We use binary logistic regression models to analyze data from a large nationwide sample of U.S. Latinos conducted by the Pew Hispanic Forum in late 2006. Results. Findings highlight the strong opposition to same-sex marriage among Latino evangelical (or conservative) Protestants and members of sectarian groups (e.g., LDS), even compared with devout Catholics. Although each of the hypothesized mediators is significantly linked with attitudes toward same-sex marriage, for the most part controlling for them does not alter the massive affiliation/attendance differences in attitudes toward same-sex marriage. Conclusions. This study illustrates the importance of religious cleavages in public opinion on social issues within the diverse U.S. Latino population. The significance of religious variations in Hispanic civic life is likely to increase with the growth of the Latino population and the rising numbers of Protestants and sectarians among Latinos

Faith, Race-Ethnicity, and Public Policy Preferences: Religious Schemas and Abortion Attitudes among U.S. Latinos

Research has demonstrated that white conservative Protestants are more opposed to abortion than their Catholic counterparts. At the same time, conservative Protestantism has made significant inroads among U.S. Latinos. This study augments existing research on religion and racial-ethnic variations in abortion attitudes by comparing levels of support for legalized abortion among Catholic and conservative Protestant Latinos. Data are drawn from a nationally representative sample of U.S. Latinos. Significantly greater opposition to abortion is found among religiously devout conservative Protestant Latinos when compared with their Catholic counterparts. Latino Catholicism, which functions as a near-monopolistic, highly institutionalized faith tradition among Hispanics, produces weaker antiabortion attitudes than those exhibited in Latino conservative Protestantism. Among Latinos, conservative Protestantism operates as a niche voluntaristic faith. These factors produce a religious schema that yields robust antiabortion attitudes. This study has important implications for understanding the intersection of race-ethnicity, religion, and public policy preferences

An Investigation of the Relationship between Big Five and Narrow Personality Traits and Life Satisfaction in College Student and Adult Samples

The purpose of this study was to examine the relationship between broad and narrow personality traits and life satisfaction for college-aged and adult populations. Hypotheses were several-fold: first, that personality measures would be predictive of life satisfaction; second, that there would be differences in the correlations of Big Five personality traits and life satisfaction for both age groups; and third, that there would be differences between both age groups in the amount of variance in life satisfaction accounted for by three narrow personality traits, i.e., Optimism, Tough-Mindedness, and Work Drive. Archival data were used to compare an undergraduate sample at a Southeastern U.S. university (n=4844), and an adult sample from a database representing working adults (n=7633). Correlation and multiple regression analyses were used for each age group in examining the validity of Big Five and narrow traits and life satisfaction. A Fischer’s z score was used to determine significant differences in the correlations by age. The Big Five and narrow traits were found to be predictive of life satisfaction for both groups, with Emotional Stability and Optimism showing the highest correlation for both age groups. There were significant differences in correlations between the age groups on measures of Extraversion (z=4.64, p\u3c.001), Agreeableness (z=1.92, p=.05), Conscientiousness (z=8.18, p\u3c.001), Openness (z=2.44, p=.01), Work Drive (z=12.82, p\u3c.001), and Tough-Mindedness (z=-2.87, p\u3c.005). Results were discussed in terms of comparing the predictive validity of personality traits and life satisfaction between the two age groups. Study limitations and directions for future research were noted

Studies on the clinical significance of nonesterified and total cholesterol in urine

Gas-liquid chromatographic determinations of nonesterified and total urinary cholesterol were performed in 137 normals, 264 patients with various internal diseases without evidence of neoplasias or diseases of the kidney or urinary tract, 497 patients with malignancies and 236 patients with diseases of the kidney, urinary tract infections or prostatic adenoma with residual urine. A normal range (mean±2 SD) of 0.2–2.2 mg/24 hours nonesterified cholesterol (NEC) and of 0.3–3.0 mg/24 hours total cholesterol (TC) was calculated. Values of urinary cholesterol excretion were independent of age and sex and did not correlate with cholesterol levels in plasma. Patients with various internal diseases, without evidence of neoplasias nor diseases of the kidney or obstruction of the urinary tract, showed normal urinary cholesterol excretions, as did patients with infections of the urinary tract. However, elevated urinary cholesterol was found in patients with diseases of the kidney or urinary tract obstruction (prostatic adenoma with residual urine), malignant diseases of the urogenital tract and metastasing carcinoma of the breast. In patients with other malignant diseases urinary cholesterol was usually normal. Lesions of the urothelial cell membranes are considered to be the most likely cause of urinary cholesterol hyperexcretion. The clinical value of urinary cholesterol determinations as a possible screening test for urogenital carcinomas in unselected populations is limited by lacking specificity, expensive methodology and low prevalence of the mentioned carcinomas, although elevated urinary cholesterol excretions have been observed in early clinical stages of urogenital cancers