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Background: Our previous studies revealed cyclicity in the incidence rate of skin malignant melanoma (SMM; ICD9, Dx: 172) in the Czech Republic (period T=7.50～7.63 years), UK (T=11.00 years) and Bulgaria (T=12.20 years). Incidences com-pared with the sunspot index Rz (lag-period dT= 2, 4, 6, 10 or 12 years) have indicated that maximal rates are most likely to appear on descending slopes of the 11-year solar cycle, i.e., out of phase. We summarized and explored more deeply these cyclic variations and discussed their possible associations with heliogeophysical activity (HGA) components exhibiting similar cyclicity. Methods: Annual incidences of SMM from 5 countries (Czech Republic, UK, Bulgaria, USA and Canada) over various time spans during the years 1964～1992 were analyzed and their correlations with cyclic Rz (sunspot number) and aa (planetary geomagnetic activity) indices were summarized. Periodogram regression analysis with trigonometric approximation and phase-correlation analysis were applied. Results: Previous findings on SMM for the Czech Republic, UK and Bulgaria have been validated, and cyclic patterns have been revealed for USA (T=8.63 years, P<0.05) and Canada (Ontario, T=9.91 years, P<0.10). Also, various 'hypercycles' were established (T=45.5, 42.0, 48.25, 34.5 and 26.5 years, respectively) describing long-term cyclic incidence patterns. The association of SMM for USA and Canada with Rz (dT= 6 and 7 years, respectively) and aa (dT=-10 and 9 years, respectively) was described. Possible interactions of cyclic non-photic influences (UV irradiation, Schumann resonance signal, low-frequency geomagnetic fluctuations) with brain waves absorbance, neuronal calcium dynamics, neuro-endocrine axis modulation, melatonin/serotonin disbalance and skin neuro-immunity impairment as likely causal pathways in melanoma appearance, were also discussed. Conclusion: The above findings on cyclicity and temporal association of SMM with cyclic environmental factors could not only allow for better forecasting models but also lead to a better understanding of melanoma aetiology. 相似文献
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This article studies the difference between the criterion validity coefficient of the widely used overall scale score for a unidimensional multicomponent measuring instrument and the maximal criterion validity coefficient that is achievable with a linear combination of its components. A necessary and sufficient condition of their identity is presented in the case of measurement errors being uncorrelated among themselves and with a used criterion. An upper bound of the difference in these validity coefficients is provided, indicating that it cannot exceed the discrepancy between the maximal reliability and composite reliability indexes. A readily applicable latent variable modeling procedure is discussed that can be used for point and interval estimation of the difference between the maximal and scale criterion validity coefficients. The outlined method is illustrated with a numerical example. 相似文献
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Brain metastases of melanoma mechanisms of attack on their defence system by engineered stem cells in the microenvironment 总被引：1，自引：1，他引：0
This report gives a better emphasis on the role of targeted effectors （e.g. a combination of 5-FC with CD-NSPCs as compared to the application of NSPCs alone） and how such delivery of pro-drug activating enzymes and other tumor-killing substances may overcome melanocytic defence system, interact with and promote the host defence and immune response modulations not only in melanoma but, potentially, in other highly-metastatic cancers. 相似文献
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Kagendo Mutua Dimiter M. Dimitrov 《International Journal of Disability, Development & Education》2001,48(2):179-191
The purpose of this study was to develop a logistic regression model for the prediction of school enrolment of Kenyan children with intellectual disabilities. The initial set of predictors included three demographic variables (child's gender, child's level of intellectual disability, and parents' level of education) and six factors of parents' expectations and beliefs about future outcomes and education of children with intellectual disabilities. Previous research implicated some of these concepts in school enrolment of children with disabilities in African countries without providing a particular prediction model. The hypothesised factor structure of the instrument developed in this study was tested by using a confirmatory maximum likelihood factor analysis. A stepwise logistic regression was conducted with the initial model including all nine predictors of school enrolment of children with intellectual disabilities in Kenya. Significant predictors in the final logistic regression model were (a) parents' expectations about social acceptance of the child, (b) parents' bias against educating children with intellectual disabilities, (c) parents' beliefs about a segregated school option, (d) parents' beliefs about the appropriateness of the child's school education, and (e) parents' level of education. 相似文献
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Mi‐Hwa Park Dimiter M. Dimitrov Ajay Das Margaret Gichuru 《Journal of Research in Special Educational Needs》2016,16(1):2-12
The Teacher Efficacy for Inclusive Practices (TEIP) scale is designed to measure teacher‐self efficacy to teach in inclusive classrooms. The original study identified three scale factors: efficacy in using inclusive instruction (EII), efficacy in collaboration (EC), and efficacy in managing behavior (EMB) (Sharma et al., 2012). The purpose of our study was to examine the TEIP scale for dimensionality and to cross‐validate its factor structure for pre‐service teachers in the context of early childhood education. A bifactor model fit to the data revealed that the TEIP scale is essentially unidimensional, that is, there is one dominant latent factor and the originally found three scale factors (EII, EC, and EMB) represent specific aspects of the general factor of teacher self‐efficacy to teach in inclusive classrooms. Along with providing validation evidence, these findings have important implications for the scoring on the TEIP scale using classical test analysis or unidimensional item response theory models. 相似文献
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A latent variable modeling method for examining the difference between maximal reliability and composite reliability for homogenous multicomponent measuring instruments is outlined. The procedure allows point and interval estimation of the discrepancy between the reliability coefficients associated with the optimal linear combination and with the popular unit-weighted sum of the scale components. The approach permits a researcher to make an informed choice if needed between the maximal reliability and composite reliability coefficients and concepts in an empirical setting as indexes of quality of measurement with an instrument under consideration. The discussed method is illustrated using numerical data. 相似文献
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We use molecular dynamics simulations with a dissipative particle dynamics thermostat to study the behavior of nanosized inclusions (colloids) in a polymer brush under shear whereby the solvent is explicitly included in the simulation. The brush is described by a bead-spring model for flexible polymer chains, grafted on a solid substrate, while the polymer-soluble nanoparticles in the solution are taken as soft spheres whose diameter is about three times larger than that of the chain segments and the solvent. We find that the brush number density profile, as well as the density profiles of the nanoinclusions and the solvent, remains insensitive to strong shear although the grafted chains tilt in direction of the flow. The thickness of the penetration layer of nanoinclusions, as well as their average concentration in the brush, stays largely unaffected even at the strongest shear. Our result manifests the remarkable robustness of polymer brushes with embedded nanoparticles under high shear which could be of importance for technological applications. 相似文献
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Dimiter M. Dimitrov 《Peabody Journal of Education》2013,88(4):637-653
This substudy in the evaluation design of the Math and Science Partnership (MSP) Program Evaluation investigates changes in student mathematics and science achievement across three school years, 2002–03, 2003–04, and 2004–05, for MSP-related schools using Management Information System data with the Annual K-12 District Survey. First, changes in percentages of students (at or above) proficient on state assessments in math and science were investigated by gender, ethnicity, special education, and students with limited English proficiency using schools for which data were available for all three years. The results indicated that MSP schools continued to show improvement in student math and science proficiency over the three-year period. Second, schools were examined by frequency and effect size of increase, decrease, or no change in student math and science proficiency from the “start” (2002–03) to the “end” (2004–05) of the period for this study. The schools with positive changes were in much higher numbers and higher mean effect size of change compared to schools with negative (or no) changes in student math and science proficiency. Third, the relationship between the schools' targeted teacher participation in MSP-related activities over the entire period of three years and the student math and science proficiency at the “end” year of this period (2004–05) was also investigated. It was found that this relationship was positive and significant for the elementary and high schools, but there was no evidence for its significance at the middle school level. 相似文献
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