A probabilistic fatigue strength model for brick masonry under compression

The paper presents the development of a model for the fatigue resistance of brick masonry under compression. The model takes into account the random nature of the fatigue strength phenomena and, as a consequence, proposes different model parameters as a function of the desired probability level. The model, based on a Weibull distribution, has been calibrated with the still limited experimental data on brick masonry under high cycle compression loading. Very good correlation is obtained. The results show that there is a clear trend of the experimental data to follow the Weibull distribution. It is also shown how the fatigue resistance of brick masonry is not only dependent on the magnitude of the stress cycles, but also on the magnitude of the minimum stress level. The paper also shows how the proposed model can be used in the reliability-based assessment of the fatigue performance of existing masonry arch bridges. Either the nominal probability of failure (reliability index) to fatigue or the remaining service life with a predefined probability level for an existing bridge can be predicted with the proposed method.     

A nurse practitioner intervention model to maximize efficient use of telemetry resources

BACKGROUND: Telemetry monitoring is widely used in hospitals; the importance of being able to monitor and examine dysrhythmias has been universally accepted. Yet it is often used for patients who do not actually require this technology. A model to improve the efficiency of telemetry use entailed the use of an advanced practice nurse (APN; identical to a nurse practitioner) to provide concurrent review and intervention of floating telemetry, which is available for patients independently of the floor location and who do not need an intensive care unit bed. ADDRESSING OVERUSE: The demand for floating telemetry at Hackensack University Medical Center had equaled or exceeded the telemetry availability virtually 100% of the time, even after local guidelines had been disseminated in 1998. The APN carried out concurrent monitoring and intervened with the attending physician when patients were on telemetry for longer than 48 hours and did not meet the local telemetry guidelines. RESULTS: The mean number (standard error [SE]) of hours per patient declined from 65.2 +/- 0.7 hours (95% confidence interval, 63.8 to 66.6 hours) for the 11 months before the intervention to a mean of 49.6 +/- 0.4 hours (95% confidence interval, 48.7 to 50.2 hours) for the 29 months after intervention--representing a decrease of 34% (p < 0.0001). This decrease led to an increase in the number of patients per month put on telemetry. DISCUSSION: The APN model, an aggressive approach that induced change almost immediately, was then applied to other quality improvement projects.     

Comparing the Canadian and American WAIS-III normative systems in inpatient neuropsychiatry and forensic psychiatry.

Canadian clinicians have used American norms for adult intelligence tests for more than 60 years. However, the availability of the Canadian norms for the WAIS-III prompts clinicians in Canada to make a decision regarding which norms to use in clinical practice. The purpose of this study is to compare the interpretive effects of applying American and Canadian normative systems in a sample of 100 forensic psychiatry and neuropsychiatry inpatients. The Canadian normative system yielded scores that were systematically lower than the American scores. Thus, clinicians may conclude greater impairment in intellectual ability when using Canadian norms. The index scores that were most similar were Processing Speed followed by Verbal Comprehension. With the exception of these two indices, clinically different conclusions might be derived on 13-21% of individual IQ or Index scores for these patients. The scores that differed the most were the Full Scale IQ and the Performance IQ. The subtests, in general, were highly similar across the normative systems, although scores using the Canadian norms were systematically lower. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reconceptualizing feeding and feeding disorders in interpersonal context: The case for a relational disorder.

The feeding of young children is fundamentally a relational and multisystemic process. Successful treatment of clinically significant feeding problems involves careful assessment of the full range of influences on the feeding relationship and integrated treatment approaches. However, current diagnostic approaches to feeding disorders tend to be reductionistic, exclusively focused on the child as an individual, and overly concerned with exclusionary criteria. Criteria are proposed for "Feeding Disorder Between Parent and Child" that address these limitations and embrace the complexity of feeding problems. A multiaxial diagnosis that describes the child (including medical, developmental, and behavioral characteristics); the parent; the parent-child relationship; and the social and nutritional context of feeding will more accurately speak to treatment planning in this population. The proposed diagnostic criteria were developed and refined on the basis of the available literature and many years of treatment experience across the authors of this article. The proposed diagnosis will support the development and evaluation of treatment packages with components specifically targeted to issues of the child, parent, parent-child interaction, and the broader environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterizing nicotine withdrawal in pregnant cigarette smokers.

Maternal smoking is a leading preventable cause of poor pregnancy outcomes and infant morbidity and mortality. Whereas pregnancy has been thought of as a "window of opportunity" when women are more motivated to change health behaviors such as smoking, only 20% of pregnant women quit smoking upon learning they are pregnant and remain abstinent at the end of the pregnancy. Greater understanding of possible obstacles to smoking during pregnancy, such as nicotine withdrawal, is needed. The symptoms of nicotine withdrawal have been well characterized in nonpregnant smokers, but there has been only 1 report conducted during pregnancy, and that was a retrospective study. The aim of the present study was to characterize nicotine withdrawal and craving in pregnant cigarette smokers. These data were collected as part of prospective clinical trials assessing the efficacy of voucher-based incentives to promote abstinence from cigarette smoking during pregnancy and postpartum. The authors examined results from the Minnesota Nicotine Withdrawal Scale (J. R. Hughes & D. K. Hatsukami, 1998) in 27 abstainers (reported no or very low levels of smoking, which was confirmed biochemically) and 21 smokers (smoked at >80% of their baseline smoking level) during the first 5 days of a cessation attempt. Abstainers reported more impatience, anger, and difficulty concentrating than did smokers. The results also suggest that pregnant smokers generally may have elevated baseline levels of withdrawal, which need to be considered in the design and analysis of future studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ground measurements for the validation of land surface temperatures derived from AATSR and MODIS data

An experimental site was set up in a large, flat and homogeneous area of rice crops for the validation of satellite derived land surface temperature (LST). Experimental campaigns were held in the summers of 2002-2004, when rice crops show full vegetation cover. LSTs were measured radiometrically along transects covering an area of 1 km². A total number of four thermal radiometers were used, which were calibrated and inter-compared through the campaigns. Radiometric temperatures were corrected for emissivity effects using field emissivity and downwelling sky radiance measurements. A database of ground-based LSTs corresponding to morning, cloud-free overpasses of Envisat/Advanced Along-Track Scanning Radiometer (AATSR) and Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Ground LSTs ranged from 25 to 32 °C, with uncertainties between ± 0.5 and ± 0.9 °C. The largest part of these uncertainties was due to the spatial variability of surface temperature. The database was used for the validation of LSTs derived from the operational AATSR and MODIS split-window algorithms, which are currently used to generate the LST product in the L2 level data. A quadratic, emissivity dependent split-window equation applicable to both AATSR and MODIS data was checked as well. Although the number of cases analyzed is limited (five concurrences for AATSR and eleven for MODIS), it can be concluded that the split-window algorithms work well, provided that the characteristics of the area are adequately prescribed, either through the classification of the land cover type and the vegetation cover, or with the surface emissivity. In this case, the AATSR LSTs yielded an average error or bias of − 0.9 °C (ground minus algorithm), with a standard deviation of 0.9 °C. The MODIS LST product agreed well with the ground LSTs, with differences comparable or smaller than the uncertainties of the ground measurements for most of the days (bias of + 0.1 °C and standard deviation of 0.6 °C, for cloud-free cases and viewing angles smaller than 60°). The quadratic split-window algorithm resulted in small average errors (+ 0.3 °C for AATSR and 0.0 °C for MODIS), with differences not exceeding ± 1.0 °C for most of the days (standard deviation of 0.9 °C for AATSR and 0.5 °C for MODIS).     

Stress exposure and stress generation in child and adolescent depression: A latent trait-state-error approach to longitudinal analyses.

In 2 longitudinal studies of negative life events and depressive symptoms in adolescents (N = 708) and in children (N = 508), latent trait-state-error structural equation models tested both the stress generation hypothesis and the stress exposure hypothesis. Results strongly suggested that self-reports of depressive symptoms reflect the influence of a perfectly stable trait factor as well as a less stable state factor. Support emerged for both the stress generation model and the stress exposure model. When the state depression factor was modeled as predicting stress, support for the stress generation model appeared to increase with age. When the trait depression factor was modeled as the predictor of stress, support for the stress generation model did not vary with the child's age. In both models, support for the stress exposure remained relatively constant across age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does solitary substance use increase adolescents' risk for poor psychosocial and behavioral outcomes? A 9-year longitudinal study comparing solitary and social users.

This longitudinal study compared Grade 8 solitary cigarette smokers (n = 541), drinkers (n = 577), and marijuana users (n = 148) with adolescents who restricted their use of these substances to social settings (ns = 562, 1,426, and 388, respectively) on adolescent functioning and young adult outcomes. In Grade 8, solitary users held more positive beliefs about the consequences of substance use, earned poorer grades, engaged in more deviant behavior, and devoted less time to school and more time to social activities. By age 23, these solitary users had lower educational attainment, poorer self-rated health, and greater substance use problems. Results indicate the importance of better understanding and addressing the needs of this understudied group of high-risk youth. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Knowledge building in mathematics: Supporting collaborative learning in pattern problems

While it has been suggested that patterning activities support early algebra learning, it is widely acknowledged that the shift from perceiving patterns to understanding algebraic functions—and correspondingly, from reporting empirical patterns to providing explanations—is difficult. This paper reports on the collaborations of grade 4 students (n = 68) from three classrooms in diverse urban settings, connected through a knowledge-building environment (Knowledge Forum), when solving mathematical generalizing problems as part of an early algebra research project. The purpose of this study was to investigate the underlying principles of idea improvement and epistemic agency and the potential of knowledge building—as supported by Knowledge Forum—to support student work. Our analyses of student-generated collaborative workspaces revealed that students were able to find multiple rules for challenging problems and revise their own conjectures regarding those rules. Furthermore, the discourse was sustained over 8 weeks and students were able to find similarities across problem types without the support of teachers or researchers, suggesting that these grade-4 students had developed a disposition for evidence use and justification that eludes much older students.     

Sustainable Development and the Sustainability of Competitive Advantage: A Dynamic and Sustainable View of the Firm

Does the need for sustainable development hinder businesses’ ability to create value? Is a firm’s competitiveness negatively affected by considering that need? After quickly reviewing the main literature contributions on the relationship between business and society, and drawing from resource‐based view of the firm and sustainable development literature, this paper presents a proposal for a dynamic and sustainable view of the firm. It shows how considering the changes introduced into the competitive landscape by sustainable development influences the way in which companies develop their resources, capabilities and activities, fostering the persistence of competitive advantages based on knowledge and innovation.