Polynomial law of sensation.

A new theory proposes that sensation grows as a polynomial function of physical intensity. The theory reproduces all of the published data perfectly without error. The degree of the polynomial is found to be always independent of all the experimental manipulations affecting the power function exponent except the number of stimuli. The polynomial law always provides a superior fit to the data, and should be used to determine the status of experimental methods and as a validity criterion for testing substantive theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limiting values of backscatter factors for low-energy x-ray beams

Models for the calculation of upper and lower limiting values to the backscatter factor (BSF) are presented. The upper limit is obtained from Monte Carlo simulations of infinite parallel beams incident on semi-infinite phantoms with the dose contributions from all orders of photon scatter considered. The lower limits are calculated using an analytical photon transport model which considers only the primary dose and the scatter dose from photons that have undergone single scattering interactions in the phantom. The limiting values can be used to evaluate measured and modelled BSF values for x-ray beams with photons of < or = 150 keV. A parametrization of the limiting values in terms of photon energy and irradiation field size is presented so that results determined for monoenergetic beams can be extended to polyenergetic spectra. The utility of the limits is illustrated by comparisons made with BSFs from the literature.     

Calculation of backscatter factors for diagnostic radiology using Monte Carlo methods

Backscatter factors were determined for x-ray beams relevant to diagnostic radiology using Monte Carlo methods. The phantom size considered most suitable for calibration of dosimeters is a cuboid of 30 x 30 cm2 front surface and 15 cm depth. This phantom size also provides a good approximation to adult patients. Three different media were studied: water, PMMA and ICRU tissue; the source geometry was a point source with varying field size and source-to-phantom distance. The variations of the backscatter factor with phantom medium and field geometry were examined. From the obtained data, a set of backscatter factors was selected and proposed for adoption as a standard set for the calibration of dosimeters to be used to measure diagnostic reference doses.     

Perceived sources of social power.

A cross-cultural analysis of the concept of power was conducted, comparing the attitudes of boys 12-14 years old in a camp for underprivileged and disturbed children and a group of female school teachers enrolled in a graduate extension course. A significantly high correlation for the 2 groups was found between the rankings of 6 traits related to the source of social power. Helpfulness and fairness were ranked highest, fearlessness and physical strength least important in regard to perceived capacity for social manipulation. From Psyc Abstracts 36:04:4GF39R. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theories of automaticity and the power law of practice.

In a recent reanalysis of numerosity judgment data from T. J. Palmeri (see record 1997-03378-004), T. C. Rickard (see record 1999-00904-017) found that mean response times did not decrease as a pure power law of practice and standard deviations systematically increased and then decreased with practice in some conditions. Rickard argued that these results were consistent with the component power laws (CMPL) theory of strategy shifting (Rickard, 1997), but were inconsistent with instance theory (G. D. Logan, 1988) and the exemplar-based random walk (EBRW) model (R. M. Nosofsky & Palmeri, 1997). In this article, the author demonstrates how a slightly more complex power function fitted the numerosity data nearly as well as the CMPL function, and how race models, such as instance theory and the EBRW, can predict deviations from a pure power law of practice and can predict nonmonotonic changes in standard deviations with practice. Potential limitations of CMPL are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Grain boundary and interphase boundary sliding in power law creep

The self-consistent theory for polycrystals and composites can be extended readily to consider the effect of grain boundary sliding where the sliding boundaries are treated as disk-shaped viscous heterogeneities of a critical volume fraction to result in contiguously connected boundary paths through the material. The approach leads to particularly simple visualizable effects of strain rate enhancement in creeping polycrystals with sliding boundaries and to readily obtainable asymptotic limiting behavior for completely relaxed boundaries over a certain range of strain rate sensitivity of the grain matrix. Finally, this approach can also be combined with a self-consistent model for creep in a heterogeneous alloy to determine the behavior of creeping composite alloys with sliding grain boundaries and entrapped interphase boundaries.     

转炉煤气回收规律及其影响因素研究

分析了转炉炉气成分和发生量随冶炼时间的变化规律 ,研究了转炉煤气回收量与影响因素之间的关系 ,给出了理想工况下的吨钢转炉煤气最大回收量。结果表明 ,铁水比提高1 % ,吨钢煤气回收量提高 1 0 89m3 /t;供氧强度提高 1m3 /(t·min) ,煤气回收量增加1 1 95 5m3 /t;若将煤气回收限制性条件放宽至CO≥ 3 5 %且O2 <1 % ,吨钢回收量提高1 5 2m3 /t;在理想工况下 ,转炉煤气最大回收量为 1 2 8 83m3 /t。     

Addition of neutron and gamma-ray fractions for intestinal damage

The microcolony assay technique has been used to test the validty of summing equivalent doses per fraction of 14 MeV neutrons and gamma rays for mouse intestinal damage. For a 4-daily fraction schedule, in which the first one or two fractions are given as neutrons and the remainder as gamma rays, combined dose fractions calculated from a 4-fraction schedule of either radiation type alone produce the same level of damage within the limits of accuracy of the experiment.     

Number of coalitions and resources as sources of power in coalition bargaining.

Investigated, using 80 female and 50 male undergraduates, the importance of 2 potential sources of power in coalition situations (number of coalitions in which the person is included and assigned resources), a potentially influential individual-differences factor (gender), and the validity of 4 theories of coalition formation (minimum power theory, the Roth-Shapely value, the weighted probability model, and bargaining theory). Five-person groups of males or females played 20 trials of a coalition game that varied the number of coalitions available to the players. Games were presented either with or without resources being assigned. Results indicate that both resources and number of alternatives influenced coalition outcomes. Players' payoffs were directly related to both factors, and coalition frequency was inversely related to the total number of alternatives available to the coalition members. Minor gender differences were also obtained. Implications for coalition theories in general and the weighted probability model in particular are discussed. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prevalence and risk factors for HBV infection among street youth in central Brazil

PURPOSE: A seroprevalence survey was carried out among 496 street adolescents from 9 to 20 years old in central Brazil to determine the prevalence of hepatitis B (HBV) markers, as well as to assess the role of potential risk factors. RESULTS: The findings reveal that 20.4% of the participants were homeless adolescents without family links, living and/or working on the streets. The age at first sexual intercourse was as low as 9 years old, and approximately 60% of this population had had at least one sexual relationship by the age of thirteen, indicating prepubertal initiation of sexual experiences among street adolescents. 13.5% were HBV marker-positive (anti-HBc) and 2.0% had antigenemia. Street-based youth had a higher HBV marker-positive rate when compared to home-based teens (OR = 4.1, 95% CI: 2.1-8.5) and, similarly, higher HBV prevalence was obtained for those reporting sexual activity versus the group without sexual activity (OR = 2.1, 95% CI: 1.1-3.9), even after adjusting for potential confounders. CONCLUSIONS: We have found that street youth, particularly street-based adolescents, should be considered at-risk group for hepatitis B infection in our region. These findings may be used as a baseline information for policy changes not only in hepatitis B prevention but also to reverse the scenario of adolescents sexual abuse.     

Risk factors for early infection of central venous catheters in pediatric patients

OBJECTIVE: To compare standard nurse-based pain therapy with a patient-controlled analgesia (PCA) regimen. DESIGN: Prospective, randomized study. SETTING: Single-institutional, clinical investigation in an urban, university-affiliated hospital. PARTICIPANTS: Sixty patients undergoing elective first-time cardiac surgery were included. INTERVENTIONS: In 30 patients, a standard analgesic regimen was used, and in 30 patients, a PCA regimen was used. The perioperative and postoperative management was similar for all patients. MEASUREMENTS AND MAIN RESULTS: Degree of sedation, satisfaction, and pain (by visual analog scale [VAS]) was assessed within the first 3 postoperative days. Vital capacity (VC) and forced expiratory volume in 1 second (FEV1) were measured using a portable spirometry system. Cortisol and troponin T (TnT) plasma levels were also measured. The expectation of pain was similar in both groups, and the postoperative pain score was significantly lower in the PCA than in the standard group throughout the study period. Significantly more piritramid was used in the PCA (total, 75.6 +/- 33.4 mg) than in the standard group (total, 20.1 +/- 31.9 mg). VC and FEV1 were significantly lower in the standard group compared with the PCA patients. Cortisol and TnT plasma levels were similar in both groups. Frequency of side effects were similar for both groups. CONCLUSION: Because of the beneficial effects with regard to degree of pain and satisfaction, pain management using PCA systems can be recommended for cardiac surgery patients. It appears to be superior to standard nurse-based pain therapy.     

关于多项式回归最优设计的一个注记

利用插值详细推导了[－1，1]上多项式回归模型饱和D-最优设计的条件，从另一角度得到与文献[1]相同的结论     

Pathogenic power of Salmonellae: virulence factors and study models

Salmonellae are potentially pathogenic for humans as well as for numerous animal species. They possess numerous virulence factors, which allow them to adapt to various environmental conditions and to host response at each step of the pathogenic process. Key-steps such as the invasion of epithelial cells or survival within macrophages have been extensively studied. These studies have led to the discovery of an original protein secretion system and have demonstrated the existence of pathogenicity islands. This considerable progress is due to the development of numerous in vitro and in vivo models and of new identification strategies for the implicated genes. Recently, many original and elegant strategies have been recently proposed.     

The Weibull distribution, the power law, and the instance theory of automaticity.

H. Colonius (1995) agreed with the fundamental tenets of the instance theory of automaticity. His article addressed the mathematical development of the theory, pointing out an error in one of two arguments that G. D. Logan (1988, 1992) used to justify the choice of the Weibull as the distribution of retrieval times and suggesting an alternative argument that places different emphasis on the power function speedup and the Weibull distribution. This article attempts to clarify the problematic argument, point out some practical limitations on H. Colonius's (1995) alternative argument, and suggest important future directions for the mathematical development of the theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

应用VQC智能控制装置提高供电系统功率因数的改造实践

本文针对公司供电系统功率因数偏低的问题进行分析,通过应用VQC智能控制装置对变压器供电系统进行无功动态补偿改造,取得了显著的节能效果和经济效益．