Anderson and Rubin and McDonald have proposed a correlation-preserving method of factor scores prediction which minimizes the trace of a residual covariance matrix for variables. Green has proposed a correlation-preserving method which minimizes the trace of a residual covariance matrix for factors. Krijnen, Wansbeek and Ten Berge have proposed minimizing the determinant rather than the trace of the latter covariance matrix, and offered an iterative procedure to that effect. In the present paper it is shown that the iterative procedure can be replaced by a closed-form solution. When all unique variances are strictly positive, this solution is the same as McDonald's. The solution coincides with Green's solution in certain special cases, for instance, when the factors are orthogonal.
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INTRODUCTION: In patients with cancer, low muscle mass has been associated with a higher risk of fatigue, poorer treatment outcomes, and mortality. To determine body composition with computed tomography (CT), measuring the muscle quantity at the level of lumbar 3 (L3) is suggested. However, in patients with cancer, CT imaging of the L3 level is not always available. Thus far, little is known about the extent to which other vertebra levels could be useful for measuring muscle status. In this study, we aimed to assess the correlation of the muscle quantity and quality between any vertebra level and L3 level in patients with various tumor localizations.METHODS: Two hundred-twenty Positron Emission Tomography (PET)-CT images of patients with four different tumor localizations were included: 1. head and neck ( n = 34), 2. esophagus ( n = 45), 3. lung ( n = 54), and 4. melanoma ( n = 87). From the whole body scan, 24 slices were used, i.e., one for each vertebra level. Two examiners contoured the muscles independently. After contouring, muscle quantity was estimated by calculating skeletal muscle area (SMA) and skeletal muscle index (SMI). Muscle quality was assessed by calculating muscle radiation attenuation (MRA). Pearson correlation coefficient was used to determine whether the other vertebra levels correlate with L3 level. RESULTS: For SMA, strong correlations were found between C1-C3 and L3, and C7-L5 and L3 ( r = 0.72-0.95). For SMI, strong correlations were found between the levels C1-C2, C7-T5, T7-L5, and L3 ( r = 0.70-0.93), respectively. For MRA, strong correlations were found between T1-L5 and L3 ( r = 0.71-0.95). DISCUSSION: For muscle quantity, the correlations between the cervical, thoracic, and lumbar levels are good, except for the cervical levels in patients with esophageal cancer. For muscle quality, the correlations between the other levels and L3 are good, except for the cervical levels in patients with melanoma. If visualization of L3 on the CT scan is absent, the other thoracic and lumbar vertebra levels could serve as a proxy to measure muscle quantity and quality in patients with head and neck, esophageal, lung cancer, and melanoma, whereas the cervical levels may be less reliable as a proxy in some patient groups.
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Seismic risk assessment of two real RC multi-story buildings, located on similar soil profile in Kocaeli, is conducted in respect to code-based linear and nonlinear approaches, as well as to P25-v2 Method, a recently suggested method for risk evaluation and preliminary assessment of existing buildings against life-loss. Twenty-five different parameters and seven different collapse criteria are taken into consideration in the suggested P25-v2 Method, including soil and topographic conditions, earthquake demand, various structural irregularities, material and geometrical properties, and location of the buildings. After summarizing the different methodologies and describing the case study buildings, 3D linear-elastic and static nonlinear analyses are performed in parallel to the application of the P25 Method-v2. One of the two case study buildings totally collapsed during 1999 Kocaeli Earthquake, while the other survived with negligible damage, noting that both had legal construction and occupation permissions. SAP2000 and SeismoStruct software packages have been utilised for the analysis procedure to find out the damage states of the structural members at critical stories and to determine the performance levels of the case study buildings. The code-based performance levels and the final performance scores obtained by the preliminary assessment technique are compared in order to underline the existence of the correlation between the detailed procedure and the suggested preliminary assessment technique with the real damage state. Consequently, structural inadequacies, weak points of the buildings and failure reasons are also discussed in this paper.
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During recent years the world has seen rapid changes such as globalization, the Internet, and the rise of new economies. To survive these changes organizations need to be in control of their processes, and be able to continuously improve the process performance. Therefore many organizations are increasingly adopting Business Process Management (BPM). However, it is not clear if the implementation of BPM(S) is really adding value to an organization. Consequently, in this paper, we try to answer the following research question: 'Does adoption of Business Process Management lead to a higher process performance?' Based on quantitative research we show that there is dependence between the performance of processes within an organization and the BPM maturity of that organization. As a result we conclude that improvement in process performance can be attained by increasing the BPM maturity of an organization.
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Background: Advanced statistical modeling techniques may help predict health outcomes. However, it is not the case that these modeling techniques always outperform traditional techniques such as regression techniques. In this study, external validation was carried out for five modeling strategies for the prediction of the disability of community-dwelling older people in the Netherlands. Methods: We analyzed data from five studies consisting of community-dwelling older people in the Netherlands. For the prediction of the total disability score as measured with the Groningen Activity Restriction Scale (GARS), we used fourteen predictors as measured with the Tilburg Frailty Indicator (TFI). Both the TFI and the GARS are self-report questionnaires. For the modeling, five statistical modeling techniques were evaluated: general linear model (GLM), support vector machine (SVM), neural net (NN), recursive partitioning (RP), and random forest (RF). Each model was developed on one of the five data sets and then applied to each of the four remaining data sets. We assessed the performance of the models with calibration characteristics, the correlation coefficient, and the root of the mean squared error. Results: The models GLM, SVM, RP, and RF showed satisfactory performance characteristics when validated on the validation data sets. All models showed poor performance characteristics for the deviating data set both for development and validation due to the deviating baseline characteristics compared to those of the other data sets. Conclusion: The performance of four models (GLM, SVM, RP, RF) on the development data sets was satisfactory. This was also the case for the validation data sets, except when these models were developed on the deviating data set. The NN models showed a much worse performance on the validation data sets than on the development data sets.
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Op 28 augustus 2014 heb ik een 'oral presentation' gegeven op het European Health Psychology Society congres te Innsbruck. De abstract van het artikel die ik gepresenteerd heb is gepubliceerd op de website van EHPS (zie bijgevoegd de link) The aim was to quantify the relationship between behavioural determinants and dental health behaviour among 9-18 year old children. Methods: Searches were conducted in PsycINFO, PubMed, CINAHL and EMBASE. In total 25 studies were included, which addressed 16 variables. A weighted average effect size correlation (WAES r) was calculated per determinant and dental health behaviour. According to Cohen (1988) effect sizes can be considered as small (r = 0.10), medium (r = 0.30) and large (r = 0.50). Findings: All WAES r’s were significant and revealed a positive relation between determinant and dental health behaviour. Large effects were found for coping planning and self-efficacy. Medium-to-large effects were found for the determinants: intention, affective attitude, and action planning. The WAES r was small-to-medium effects were found for: social norms, cognitive attitude, knowledge, parental oral health behaviour and parental cognitions. Discussion: Although the number of studies focusing on volitional factors are limited, the overall findings highlight the importance of volitional factors, rather than knowledge or motivational factors in explaining dental health behaviour. Refbacks There are currently no refbacks.
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Aims and objectives. The Forensic Early Warning Signs of Aggression Inventory (FESAI) was developed to assist nurses and patients in identifying early warning signs and constructing individual early detection plans (EDP) for the prevention of aggressive incidents. The aims of this research were as follows: First, to study the prevalence of early warning signs of aggression, measured with the FESAI, in a sample of forensic patients, and second, to explore whether there are any types of warning signs typical of diagnostic subgroups or offender subgroups. Background. Reconstructing patients’ changes in behaviour prior to aggressive incidents may contribute to identify early warning signs specific to the individual patient. The EDP comprises an early intervention strategy suggested by the patient and approved by the nurses. Implementation of EDP may enhance efficient risk assessment and management. Design. An explorative design was used to review existing records and to monitor frequencies of early warning signs. Methods. Early detection plans of 171 patients from two forensic hospital wards were examined. Frequency distributions were estimated by recording the early warning signs on the FESAI. Rank order correlation analyses were conducted to compare diagnostic subgroups and offender subgroups concerning types and frequencies of warning signs. Results. The FESAI categories with the highest frequency rank were the following: (1) anger, (2) social withdrawal, (3) superficial contact and (4) non-aggressive antisocial behaviour. There were no significant differences between subgroups of patients concerning the ranks of the four categories of early warning signs. Conclusion. The results suggest that the FESAI covers very well the wide variety of occurred warning signs reported in the EDPs. No group profiles of warning signs were found to be specific to diagnosis or offence type. Relevance to clinical practice. Applying the FESAI to develop individual EDPs appears to be a promising approach to enhance risk assessment and management.
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Human activity is omnipresent in our landscapes. Animals can perceive risk from humans similar to predation risk, which could affect their fitness. We assessed the influence of the relative intensity of recreational activities on the bodyweight and pregnancy rates of red deer (Cervus elaphus) between 1985 and 2015. We hypothesized that stress, as a result of recreational activities, affects the pregnancy rates of red deer directly and indirectly via a reduction in bodyweight. Furthermore, we expected non-motorized recreational activities to have a larger negative effect on both bodyweight and fecundity, compared to motorized recreational activities. The intensity of recreational activities was recorded through visual observations. We obtained pregnancy data from female red deer that were shot during the regular hunting season. Additionally, age and bodyweight were determined through a post-mortem examination. We used two Generalized-Linear-Mixed Models (GLMM) to test the effect of different types of recreation on (1) pregnancy rates and (2) bodyweight of red deer. Recreation had a direct negative correlation with the fecundity of red deer, with bodyweight, as a mediator as expected. Besides, we found a negative effect of non-motorized recreation on fecundity and bodyweight and no significant effect of motorized recreation. Our results support the concept of humans as an important stressor affecting wild animal populations at a population level and plead to regulate recreational activities in protected areas that are sensitive. The fear humans induce in large-bodied herbivores and its consequences for fitness may have strong implications for animal populations.Projectnummer: SVB/RAAK.PRO 02.048
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