Energy Distribution of a Charged Black Hole with a Minimally Coupled Scalar Field

Using three different energy-momentum complexes, the Einstein, Landau-Lifshitz, and Papapetrou prescriptions, we calculate the energy of an electrically charged black hole exact solution with a self-interacting, minimally-coupled scalar field and the asymptotic region locally an Anti-deSitter spacetime. Writing the metric in Kerr-Schild Cartesian coordinates, we demonstrate that this metric belongs to the Kerr-Schild class of solutions. Applying each of the three energy-momentum prescriptions and comparing the results, we find consistency among these complexes, suggesting their utility as localized measures of energy.Comment: 11 pages; To appear in Astrophysics and Space Scienc

Evaluating cardiac anatomy as a predictor for success after pulmonary vein isolation for the treatment of atrial fibrillation

Introduction: Atrial Fibrillation is a condition characterized by the production of ectopic beats by the heart. One common treatment for Atrial Fibrillation is catheter guided pulmonary vein isolation (PVI), however this treatment is only effective in around 60-70% of the population. Our research hopes to elucidate a link between cardiac anatomy and successful treatment of A-fib by pulmonary vein isolation. Methods: The medical records for 78 consecutive patients who underwent PVI for atrial fibrillation at Jefferson from July 2013 to March 2016 were gathered. Included in these charts were ECG-gated cardiac CT angiogram and two-year follow up history. Different variables from the imaging data such as left atrial volume, ejection fraction, and pulmonary vein area were analyzed and compared to likelihood of recurrence of A-Fib after PVI. A T-test was used to compare continuous variables in patients who had recurrence versus those that did not and a Chi-Squared Test was used to compare likelihood of recurrence in those with persistent versus paroxysmal A-Fib. Results: Recurrent atrial fibrillation was found in 32/72 (44%) of treated patients by 24 months. Univariate analysis demonstrated a higher incidence of recurrent atrial fibrillation among patients who remained on anti-arrhythmic medications 14/22 = as compared to those who did not 18/50, p = 0.03. There was a lower incidence of recurrent atrial fibrillation in males 20/52 (38%) as compared with females 12/19 (63%), though this difference was only marginally significant (p = 0.056). Multivariate analysis of additional variables with logistic regression demonstrated a marginally significant association of reduced ejection fraction with recurrent atrial fibrillation (p= 0.064). Logistic regression analysis demonstrated no significant differences in recurrence rate based upon age, paroxysmal/persistent fibrillation, left atrial volume, CHADS2 score, pulmonary vein area, and catheter type. Discussion: The only marginal predictors for recurrent atrial fibrillation after PVI were Gender and left ventricular ejection fraction. The other variables including anatomical features and the catheter type used for the procedure had no significant impact on long-term recurrence rates after PVAI. This was a surprising result given other data in the field, which seemed to indicate a link between cardiac anatomy and recurrence of A-Fib after PVI. More research should be conducted in this area, perhaps with a larger data set then was used in this study

Five-Dimensional Space-Times

The set of all spatially homogeneous (4+1)-dimensional cosmologies will be explored. We will utilize a classification of these space-times based on the actions of isometry groups on these manifolds. Several exact solutions of the Einstein equations will be derived. The possibilities of dimensional reduction and isotropization will be examined. Five-dimensional generalizations of the mixmaster universe will be developed. Finally, the Einstein equations in 4+1 dimensions will be viewed as a Hamiltonian system. The absence of chaotic solutions to these equations will be shown

Parents\u27 Gender Ideology and Gendered Behavior as Predictors of Children\u27s Gender-Role Attitudes: A Longitudinal Exploration

This longitudinal study examined the association between parents’ early and concurrent gender ideology and gendered behaviors and their children’s gender-role attitudes at age six. Specifically, parents\u27 global beliefs about women\u27s and men\u27s rightful roles in society, as well as their work preferences for mothers, were considered in relation to the gender-role attitudes held by their first-graders. In addition, parents’ gendered behaviors, including their division of household and childcare tasks, division of paid work hours, and job traditionality were examined as predictors of children’s gender-role attitudes. Based on previous research, it was hypothesized parents’ early and concurrent behavior and ideology would predict children’s gender-role attitudes in unique ways, and that overall, parents\u27 behavior would be more influential than their ideology in the development of their children\u27s understanding of gender roles. It was also hypothesized that fathers’ ideologies would be more closely related to sons’ attitudes than daughters’ attitueds. Partial support was found for these hypotheses, and findings varied across three measures of children’s gender-role attitudes. The present study is the first of its kind to examine the relationships between both mothers’ and fathers’ gender ideology and gendered behavior with children’s gender-role attitudes from a longitudinal perspective. Findings from the current study will fill gaps in the literature on children’s gender development in the context of the family, and offer the benefit of a longitudinal exploration of the relationship between parents’ gender ideologies, gendered behavior, and children’s gender-role attitudes. Several limitations, including those related to the nature of the sample, are addressed

Another Look at History

Stephen Roskill’s two-volume Naval Policy between the Wars (London: Collins, 1968 and 1976) has dominated the history of Britain’s interwar navy. Roskill—author of the official British naval history of World War II—had a vast store of knowledge, as well as personal experience and contacts with many of the individuals about whom he wrote

Too Close for Comfort: The Role of the Closely Held Public Corporation in the Canadian Economy and the Implications for Public Policy

For several decades, American corporate scholars assumed the inevitability of the widely held Berle and Means\u27 corporation. The argument was simple. In a rapidly developing industrial economy, economic prosperity dictated the infusion of massive amounts of capital into owner-managed corporations. Without ample capital, entrepreneurs would be unable to realize the scale economies or technological innovations necessary for industrial growth. The rub in the story, however, was that to raise the necessary capital, owner-managers had to sell off equity interests. Inevitably, the pressure for capital meant that ownership ended up being dispersed among numerous small stakes shareholders. With ownership fractured, sundry collective action problems subverted the capacity of shareholders to wield effective control over their managerial agents, which, in tum, meant efficiency losses from sub-optimal resource utilization. Recently, however, recognition of the survival of concentrated share ownership corporations in other countries, namely Germany and Japan and even in the United States, has caused American scholars to reconsider their commitment to the evolutionary inevitability of the Berle and Means\u27 corporation. No longer the byproduct of innate economic forces, the American corporation has of late been viewed by many as merely path dependent, more particularly the result of a confluence of political, historical and cultural factors. Perhaps the most important was the restriction barring financial intermediaries from holding or voting ownership interests in commercial companies. Had these barriers not been created, ownership may have come to reside in sophisticated large stakes shareholders, who were much more likely than retail investors to control managerial agents