Isotropization of Bianchi type models and a new FRW solution in Brans-Dicke theory

Using scaled variables we are able to integrate an equation valid for isotropic and anisotropic Bianchi type I, V, IX models in Brans-Dicke (BD) theory. We analyze known and new solutions for these models in relation with the possibility that anisotropic models asymptotically isotropize, and/or possess inflationary properties. In particular, a new solution of curve ($k\neq0$) Friedmann-Robertson-Walker (FRW) cosmologies in Brans-Dicke theory is analyzed.Comment: 15 pages, 4 postscript figures, to appear in Gen. Rel. Grav., special issue dedicated in honour of Prof. H. Dehne

Isotropization of Bianchi-Type Cosmological Solutions in Brans-Dicke Theory

The cosmic, general analitic solutions of the Brans--Dicke Theory for the flat space of homogeneous and isotropic models containing perfect, barotropic, fluids are seen to belong to a wider class of solutions --which includes cosmological models with the open and the closed spaces of the Friedmann--Robertson--Walker metric, as well as solutions for models with homogeneous but anisotropic spaces corresponding to the Bianchi--Type metric clasification-- when all these solutions are expressed in terms of reduced variables. The existence of such a class lies in the fact that the scalar field, $\phi$, times a function of the mean scale factor or ``volume element'', $a^3 = a_1 a_2 a_3$, which depends on time and on the barotropic index of the equation of state used, can be written as a function of a ``cosmic time'' reduced in terms of another function of the mean scale factor depending itself again on the barotropic index but independent of the metrics here employed. This reduction procedure permites one to analyze if explicitly given anisotropic cosmological solutions ``isotropize'' in the course of their time evolution. For if so can happen, it could be claimed that there exists a subclass of solutions that is stable under anisotropic perturbations.Comment: 15 pages, Late

Propensity-matched analysis of patient-reported outcomes for neoadjuvant chemotherapy prior to radical cystectomy

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: To evaluate patient-reported outcomes (PROs) for bladder cancer patients undergoing neoadjuvant chemotherapy (NAC) prior to radical cystectomy (RC) using longitudinal data and propensity-matched scoring analyses. Methods: 155 patients with muscle-invasive bladder cancer scheduled for RC completed the European Organization for Research and Treatment of Cancer questionnaires, EORTC QLQ-C30, EORTC QLQ-BLM30, Fear of Recurrence Scale, Mental Health Inventory and Satisfaction with Life Scale within 4 weeks of surgery. A propensity-matched analysis was performed comparing pre-surgery PROs among 101 patients who completed NAC versus 54 patients who did not receive NAC. We also compared PROs pre- and post-chemotherapy for 16 patients who had data available for both time points. Results: In propensity-matched analysis, NAC-treated patients reported better emotional and sexual function, mental health, urinary function and fewer financial concerns compared to those that did not receive NAC. Longitudinal analysis showed increases in fatigue, nausea and appetite loss following chemotherapy. Conclusion: Propensity-matched analysis did not demonstrate a negative effect of NAC on PRO. Several positive associations of NAC were found in the propensity-matched analysis, possibly due to other confounding differences between the two groups or actual clinical benefit. Longitudinal analysis of a small number of patients found small to modest detrimental effects from NAC similar to toxicities previously reported. Our preliminary findings, along with known survival and toxicity data, should be considered in decision-making for NAC

Nonlinear Circuits

Contains reports on four research projects

Alleviation of Buffet-Induced Vibration Using Piezoelectric Actuators

Buffet-induced vibration has been problematic for aircraft structures for many years. The F-16 ventral fin, while prone to these effects, lends itself well to the evaluation of modern active structural and flow control technologies. The objective of this research was to determine the most critical natural modes of vibration for the F-16 ventral fin and design piezoelectric actuators capable of reducing buffet-induced ventral fin vibration. A finite element model (FEM) for the fin was developed, tuned and optimized to closely match published modal frequencies. Piezoelectric actuator patches were designed using the strain characteristics of the FEM and integrated into the model using a thermal analogy which allowed voltage application and the resulting strain to be simulated by a change in temperature. Two phases of critical mode selection were completed and included reviews of existing flight test data, historical ventral fin failure characteristics, and the results of aeroelastic and closed-loop aeroservoelastic analyses conducted on the FEM. Results showed the FEM tuning and optimization procedures, as well as the design and implementation process for the piezoelectric actuators to be very effective. Modes 1, 2 and 4 were determined to be the most suitable for future application of the technology

SMALL GROUP DECISION MAKING IN TELECONFERENCING SETTINGS: AN EXPLICATION AND TEST OF THE INTERPERSONAL CLOSENESS-DISTANCE MODEL SMALL GROUP DECISION MAKING IN TELECONFERENCING SETTINGS: AN EXPLICATION AND TEST OF THE INTERPERSONAL CLOSENESS-DISTANCE MODEL

Abstract This study describes an initial structure for and test of a model of interpersonal closeness-distance with the objective of gaining a better understanding of small group decision making in different teleconferencing settings. 256 subjects randomly assigned to 64 small decision making groups were asked to reach a group consensus on an information exchange task with a criterion solution. These groups were randomly assigned to one of four conference format conditions: communication via face-to-face, audio, video, or computer channels. Conferencing format was found to be related to perceptions of group consensus and satisfaction and to decision making efficiency when the four types of conferencing formats were compared. No significant difference was found between the four formats in terms of the quality of the decision made

Mutational Analysis of the Respiratory Nitrate Transporter NarK2 of <em>Mycobacterium tuberculosis</em>

<div><p><em>Mycobacterium tuberculosis</em> induces nitrate reductase activity in response to decreasing oxygen levels. This is due to regulation of both the transcription and the activity of the nitrate transporter NarK2. A model of NarK2 structure is proposed containing 12 membrane spanning regions consistent with other members of the major facilitator superfamily. The role of the proton gradient was determined by exposing <em>M. tuberculosis</em> to uncouplers. Nitrite production decreased indicating that the importation of nitrate involved an H⁺/nitrate symporter. The addition of nitrite before nitrate had no effect, suggesting no role for a nitrate/nitrite antiporter. In addition the NarK2 knockout mutant showed no defect in nitrite export. NarK2 is proposed to be a Type I H⁺/nitrate symporter. Site directed mutagenesis was performed changing 23 amino acids of NarK2. This allowed the identification of important regions and amino acids of this transporter. Five of these mutants were inactive for nitrate transport, seven produced reduced activity and eleven mutants retained wild type activity. NarK2 is inactivated in the presence of oxygen by an unknown mechanism. However none of the mutants, including those with mutated cysteines, were altered in their response to oxygen levels. The assimilatory nitrate transporter NasA of <em>Bacillus subtilis</em> was expressed in the <em>M. tuberculosis</em> NarK2 mutant. It remained active during aerobic incubation showing that the point of oxygen control is NarK2.</p> </div