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Reasonable Choice (reasonable + choice)
Selected AbstractsEnergy transfer in master equation simulations: A new approachINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 12 2009John R. BarkerArticle first published online: 8 OCT 200 Collisional energy transfer plays a key role in recombination, unimolecular, and chemical activation reactions. For master equation simulations of such reaction systems, it is conventionally assumed that the rate constant for inelastic energy transfer collisions is independent of the excitation energy. However, numerical instabilities and nonphysical results are encountered when normalizing the collision step-size distribution in the sparse density of states regime at low energies. It is argued here that the conventional assumption is not correct, and it is shown that the numerical problems and nonphysical results are eliminated by making a plausible assumption about the energy dependence of the rate coefficient for inelastic collisions. The new assumption produces a model that is more physically realistic for any reasonable choice of collision step-size distribution, but more work remains to be done. The resulting numerical algorithm is stable and noniterative. Testing shows that overall accuracy in master equation simulations is better with this new approach than with the conventional one. This new approach is appropriate for all energy-grained master equation formulations. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 748,763, 2009 [source] A comparison of root surface instrumentation using two piezoelectric ultrasonic scalers and a hand scaler in vivoJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2007H. Kawashima Background and Objective:, This study compared the effectiveness of two piezoelectric ultrasonic scalers and a hand scaler for subgingival scaling and root planing in vivo. Material and Methods:, Fifteen patients with advanced periodontal disease and with teeth scheduled for extraction were selected for this study. Three experimental groups of 10 teeth each were treated with one of two piezoelectric ultrasonic scalers [VectorÔ scaler and Enac® scaler] or with a hand scaler. Instrumentation was continued until the root surface felt hard and smooth to an explorer tip. The root surface characteristics after instrumentation were examined using scanning electron microscopy, and the amount of remaining calculus, roughness and loss of tooth substance were estimated using the remaining calculus index and roughness loss of tooth substance index. Results:, The remaining calculus index did not differ significantly among the three groups. The roughness loss of tooth substance index was significantly lower for the VectorÔ scaler and Enac® scaler groups than for the hand scaler group and also differed significantly between the VectorÔ scaler and Enac® scaler groups. Conclusion:, This study suggests that the VectorÔ scaler produces a smooth root surface with minimal loss of tooth substance. It is a reasonable choice for gentle periodontal maintenance treatment. [source] Precessing warped accretion discs in X-ray binariesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2001G. I. Ogilvie We study the radiation-driven warping of accretion discs in the context of X-ray binaries. The latest evolutionary equations are adopted, which extend the classical alpha theory to time-dependent thin discs with non-linear warps. We also develop accurate, analytical expressions for the tidal torque and the radiation torque, including self-shadowing. We investigate the possible non-linear dynamics of the system within the framework of bifurcation theory. First, we re-examine the stability of an initially flat disc to the Pringle instability. Then we compute directly the branches of non-linear solutions representing steadily precessing discs. Finally, we determine the stability of the non-linear solutions. Each problem involves only ordinary differential equations, allowing a rapid, accurate and well-resolved solution. We find that radiation-driven warping is probably not a common occurrence in low-mass X-ray binaries. We also find that stable, steadily precessing discs exist for a narrow range of parameters close to the stability limit. This could explain why so few systems show clear, repeatable ,superorbital' variations. The best examples of such systems, Her X-1, SS 433 and LMC X-4, all lie close to the stability limit for a reasonable choice of parameters. Systems far from the stability limit, including Cyg X-2, Cen X-3 and SMC X-1, probably experience quasi-periodic or chaotic variability as first noticed recently by Wijers and Pringle. We show that radiation-driven warping provides a coherent and persuasive framework but that it does not provide a generic explanation for the long-term variabilities in all X-ray binaries. [source] Bulk and epitaxial growth of micropipe-free silicon carbide on basal and rhombohedral plane seedsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2008B. M. Epelbaum Abstract In this paper the criteria for reasonable choice of alternative to (0001) seed orientation are discussed. Growth conditions necessary to produce bulk 6H- and 4H-SiC crystals on rhombohedral (01-1n) plane seeds in PVT process are presented. Specific defect structures in such crystals are described in relation to growth conditions. In the second part of the paper, liquid phase epitaxial (LPE) growth using high-temperature silicon based flux and rhombohedral plane seeds is compared to the LPE on basal plane seeds. In both bulk and epitaxial growth processes the employment of rhombohedral plane seed offers important advantages. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Partial Ownership For The Public Firm And CompetitionTHE JAPANESE ECONOMIC REVIEW, Issue 3 2003Sang-Ho Lee This paper investigates the issue of partial ownership (partial privatization) of a state-owned public enterprise. We elaborate on the framework of Matsumura (1998) by allowing for managerial inefficiency, and show that under moderate conditions partial ownership is a reasonable choice of government in a monopoly market as well as in a mixed duopoly market, where a public firm competes with a profit-maximizing private firm. We also provide some economic rationale on the result that neither full privatization nor full nation-alization is optimum. [source] Declining medical decision-making capacity in mild AD: a two-year longitudinal study,BEHAVIORAL SCIENCES & THE LAW, Issue 4 2006Justin S. Huthwaite Psy.D. This is a report of a two-year longitudinal study comparing healthy older adult subjects (n,=,15) and mild Alzheimer's disease (AD) patients (n,=,20) using an objective performance measure of medical decision-making capacity (MDC). Capacity to consent to medical treatment was measured using the Capacity to Consent to Treatment Instrument (CCTI). The CCTI is a psychometric measure that tests MDC using a series of four core capacity standards: S1 (evidencing/communicating choice), S3 (appreciating consequences), S4 (providing rational reasons), and S5 (understanding treatment situation), and one experimental standard [S2] (making the reasonable treatment choice). For each standard, mild AD patients were assigned one of three capacity outcomes (capable, marginally capable, or incapable) based on cut-off scores derived from control group performance. At baseline, mild AD patients performed equivalently with controls on simple standards of evidencing a choice (S1) and making the reasonable choice ([S2]), but significantly below controls on complex standards of appreciation, reasoning, and understanding (S3, S4, and S5) (p,<,0.02). Control performance was stable over time on all capacity standards. At one-year follow-up, the mild AD group did not show significant decline from baseline on any capacity standard. However, at two-year follow-up the mild AD group showed significant declines from baseline on the three complex standards (S3, S4, and S5) (p,<,0.02), and a trend on one of the simple standards (S1). Over the two-year period, the proportion of marginally capable and incapable outcomes in the AD group increased substantially for four of the five standards (S1, S3, S4, and S5). Performance on [S2] remained stable over time in the AD group. We conclude that mild AD patients have impaired MDC at baseline, and demonstrate significant additional decline on complex consent abilities of appreciation, reasoning, and understanding over a two-year period. AD patients also show emerging impairment on the simple consent ability of evidencing choice at two-year follow-up. Capacity outcome data reflect similar declines over time for these four consent standards. The findings suggest the value of early assessment and regular monitoring at two-year intervals of MDC in patients with mild AD. Copyright © 2006 John Wiley & Sons, Ltd. [source] Extinction risk under coloured environmental noiseECOGRAPHY, Issue 2 2000Mikko Heino Positively autocorrelated red environmental noise is characterized by a strong dependence of expected sample variance on sample length. This dependence has to be taken into account when assessing extinction risk under red and white uncorrelated environmental noise. To facilitate a comparison between red and white noise, their expected variances can be scaled to be equal, but only at a chosen time scale. We show with a simple one-dimensional population dynamics model that the different but equally reasonable choices of the time scale yield qualitatively different results on the dependence of extinction risk on the colour of environmental noise: extinction risk might increase as well as decrease when the temporal correlation of noise increases. [source] Learning to Live with Our ChildrenPUBLIC HEALTH NURSING, Issue 6 2006Henrietta Fleck ABSTRACT As the title suggests, being perplexed by one's children is not unique to the 21st century. In her paper, published in the original Public Health Nursing, Henrietta Fleck (1949), chair of Home Economics at New York University, addressed this persistent problem by providing advice on parent education methods for public health nurses. The materials,films, newspapers, cartoons, posters,are all within the nurse's arsenal today, supplemented by television, and the Internet. More interesting was Fleck's philosophy about parenting and family life. The excerpt omits the dated description of resources, focusing instead on her point of view. It reflects post-World War II optimism about the meaning and power of democracy in shaping familial behavior. The United States was readjusting to civilian life following World War II, fathers were returning home from military fields of action overseas, women were gradually being displaced from the industrial workplace,the country was expanding into suburbia and baby boomers were making their first appearances in the world. Fleck's assumptions include belief in the value of individualism, the importance of sharing both privilege and obligation, and the nature of maturity evidenced in an ability to make reasoned and reasonable choices and to hold oneself accountable for them. The limitations of her view are left to us to ponder. [source] |