High Intercorrelations Research Articles

Multivariate studies and heavy metal pollution in soil from gold mining area

Mining generates large volumes of waste, which if not regulated can release toxic metals, causing widespread environmental contamination. This study focused on heavy metal contamination in topsoil within a mining area at Nangodi in the Northern Region of Ghana. A total of 24 soil samples were collected from the study area and control samples were analyzed for Hg, Pb, Cd, As, Cr, and Fe using atomic absorption spectroscopy. Results of Pollution Index estimations and Geo-accumulation index (Igeo) classified the soil samples as moderately contaminated to heavily contaminated. Soil samples were severely enriched with As and moderately enriched with b, and Hg. Multivariate analyses such as factor analysis and cluster analysis were employed to examine the relationship between the metals and also differentiate the influence of the natural background content of metals from that due to human activities. Factor analysis identified three polluted soil factor associations. Cadmium, Fe, As, and Pb associated with factor 1, were due to anthropogenic activities. The high intercorrelation revealed by As and Pb shows similarity in their sources. Factor two dominated by Hg is considered an anthropogenic component. Factor 3 correlated with Cr and can be considered a natural component. Correlation analysis and cluster analysis supported each other. Results from the bi-plots showed that sites S1, S8, S11, and S18, have similar metal composition as the control site. Heavy metal contents in soils sampled from Zones A and B have been influenced by the mining activities as seen from the associations of these sites in the bi-plots. The results are useful for metal source identification, and can contribute to monitoring and regulatory programs.

The use of principal component analysis for reduction of training load data in professional soccer

The aim of this study was to explore the use of principal component analysis (PCA) in understanding multivariate relationships in soccer training load data. Training load data were collected from 20 professional male soccer players during a 28-week in-season period. Twelve training load variables (total distance, PlayerLoadTM, low-speed running distance, moderate-speed running distance, high-speed running distance, sprint distance, moderate-speed running efforts, high-speed running efforts, sprint efforts, accelerations, decelerations, and changes of direction) were collected during training sessions, with correlation analysis revealing high intercorrelation between most variables (r = 0.04-0.98). Principal component analysis was performed on datasets containing all players and on individual players. On the whole dataset, two principal components were retained explaining a total of 81% of data variance. The first component comprised variables associated with distances in speed zones and the second component changes of direction. Whilst some individual variation existed among players, distances in speed zones were loaded on the first component and inertial movement analysis variables, such as accelerations, decelerations, and changes of direction, were loaded on the second component. These findings evidence the strong relationships between several common training load variables and highlight the risk of data redundancy. By selecting variables from each component, practitioners can reduce the number of variables reported whilst retaining as much of the variation in data as possible.

Predictors of sustainment of two distinct nutrition and physical activity programs in early care and education.

The goal of the present study was to investigate factors associated with sustainment of two evidence-based programs for nutrition promotion in early care and education (ECE) settings - Food Friends (FF) and Together, We Inspire Smart Eating (WISE). In a cross-sectional study design, ECE directors (N = 55) from centers that had previously been trained in WISE or FF completed a survey. Program-specific measures included Steckler's Perception of Innovations, the Program Sustainability Assessment Tool (PSAT), and the Organizational Readiness for Change Assessment (ORCA). For our primary outcomes, two measures of sustainment were examined: Nutrition Continued Practice (i.e., the use of or general focus on nutrition programs) and Program Fidelity (i.e., how well centers used specific evidence-based practices of WISE or FF). Multiple regression was used to determine the association of these outcomes with program, years since last implementation, and overall scores on predictors. Follow-up correlation analyses were used to investigate outcome relationships with context submeasures due to high intercorrelations between predictor submeasures. Nutrition Continued Practice was significantly predicted by program and overall PSAT score. WISE programs had significantly higher Nutrition Continued Practice scores than FF program (p = 0.03). All subscales of the PSAT (e.g., environmental support, funding stability, organizational capacity, program adaptation, communications, and strategic planning) were significantly correlated with Nutrition Continued Practice (all rs > 0.30, all ps < 0.03). Program Fidelity was significantly predicted by PSAT and Steckler Perception of Innovation scores. All subscales of the PSAT were strongly positively correlated with Program Fidelity (all rs > 0.48, all ps < 0.001); relative advantage (r = 0.54, p < 0.001) and level of institutionalization (r = 0.61, p < 0.001) were positively correlated with Program Fidelity. This study suggests that factors associated with the continued practice of program principles are partially distinct from those that are associated with the sustainment of specific practices driving program fidelity. Results suggest capacity building strategies may be important for both continued attention to nutrition and physical activity as well as sustaining fidelity to specific evidence-based practices.

The brief case for everyday problems: a proposal of two brief alternate forms of the Everyday Problems Test.

Everyday Problems Test (EPT; Willis and Marsiske, Manual for the everyday problems test, Pennsylvania State University, Pennsylvania, 1993) is an 84-item performance-based measure of older adults' everyday cognitive competencies in seven everyday domains (e.g., finance, reading prescription). Its length makes it disadvantageous in the typical time-constrained testing context. Due to the potential practice effects, it is also impractical for longitudinal and intervention studies which require repetitive testing. We have addressed these issues by adapting two brief forms of EPT, with 14 items each. The psychometric evaluation of these two versions was conducted on a sample of 157 cognitively healthy older adults. Both brief forms demonstrated good internal consistency, high inter-correlation, and have shown satisfactory concurrent criterion-related validity based on their correlations with socio-demographic and cognitive variables. Results indicate that the two proposed brief forms can be a valuable tool in assessing the everyday cognitive competence of healthy older adults either as a one-time screening instrument or as a pretest-posttest difference indicator of the intervention efficacy.

Validity of the NIH toolbox cognitive battery in a healthy oldest-old 85+ sample.

To evaluate the construct validity of the NIH Toolbox Cognitive Battery (NIH TB-CB) in the healthy oldest-old (85+ years old). Our sample from the McKnight Brain Aging Registry consists of 179 individuals, 85 to 99 years of age, screened for memory, neurological, and psychiatric disorders. Using previous research methods on a sample of 85 + y/o adults, we conducted confirmatory factor analyses on models of NIH TB-CB and same domain standard neuropsychological measures. We hypothesized the five-factor model (Reading, Vocabulary, Memory, Working Memory, and Executive/Speed) would have the best fit, consistent with younger populations. We assessed confirmatory and discriminant validity. We also evaluated demographic and computer use predictors of NIH TB-CB composite scores. Findings suggest the six-factor model (Vocabulary, Reading, Memory, Working Memory, Executive, and Speed) had a better fit than alternative models. NIH TB-CB tests had good convergent and discriminant validity, though tests in the executive functioning domain had high inter-correlations with other cognitive domains. Computer use was strongly associated with higher NIH TB-CB overall and fluid cognition composite scores. The NIH TB-CB is a valid assessment for the oldest-old samples, with relatively weak validity in the domain of executive functioning. Computer use's impact on composite scores could be due to the executive demands of learning to use a tablet. Strong relationships of executive function with other cognitive domains could be due to cognitive dedifferentiation. Overall, the NIH TB-CB could be useful for testing cognition in the oldest-old and the impact of aging on cognition in older populations.

Psychometric properties of the Greek translation of the Friendship Quality Questionnaire

AbstractThe present study examines the psychometric properties of the long form (LF) of the Greek translation of the Friendship Quality Questionnaire (FQQ), a widely recognized self‐report instrument that assesses children's perceptions of the qualities of their friendships. Four hundred seventeen (417) typically developing primary‐school students (50.8% boys), aged between 8 and 12 years (M = 9.77 years old, SD = 1.2), who had a mutual best friend in their class, completed the survey at school. Confirmatory factor analysis verified the six‐factor structure of the original FQQ with all items fitting into the respective subscales. All factors presented high positive intercorrelations except for the Conflict and Betrayal subscale. All subscales demonstrated adequate internal consistency. Significant gender differences were observed. The Greek translation of the FQQ‐LF shows strong evidence of validity and reliability and provides a suitable instrument for assessing the qualitative characteristics of best friendships.

Regional Reconstruction of Po River Basin (Italy) Streamflow

The Po River Basin (PRB) is Italy’s largest river system and provides a vital water supply source for varying demands, including agriculture, energy (hydropower), and water supply. The current (2022) drought has been associated with low winter–early spring (2021–2022) snow accumulation in higher elevations (European Alps) and a lack of late spring–early summer (2022) precipitation, resulting in deficit PRB streamflow. Many local scientists are now estimating a 50- to 100-year (return period) drought for 2022. Given the importance of this river system, information about past (paleo) drought and pluvial periods would provide important information to water managers and planners. Annual streamflow data were obtained for thirteen gauges that were spatially located across the PRB. The Old World Drought Atlas (OWDA) provides annual June–July–August (JJA) self-calibrating Palmer Drought Severity Index (scPDSI) data for 5414 grid points across Europe from 0 to 2012 AD. In lieu of tree-ring chronologies, this dataset was used as a proxy to reconstruct PRB regional streamflow. Singular value decomposition (SVD) was applied to PRB streamflow gauges and gridded scPDSI data for two periods of record, referred to as the short period of record (SPOR), 1980 to 2012 (33 years), and the long period of record (LPOR), 1967 to 2012 (46 years). SVD serves as both a data reduction technique, identifying significant scPDSI grid points within the selected 450 km search radius, and develops a single vector that represents the regional PRB streamflow variability. Due to the high intercorrelations of PRB streamflow gauges, the SVD-generated PRB regional streamflow vector was used as the dependent variable in regression models for both the SPOR and LPOR, while the significant scPDSI grid points (cells) identified by SVD were used as the independent variables. This resulted in two highly skillful regional reconstructions of PRB streamflow from 0 to 2012. Multiple drought and pluvial periods were identified in the paleo record that exceed those observed in the recent historical record, and several of these droughts aligned with paleo streamflow reconstructions of neighboring European watersheds. Future research will utilize the PRB reconstructions to quantify the current (2022) drought, providing a first-time paleo-perspective of drought frequency in the watershed.

Political bullshit receptivity and its correlates: A cross-country validation of the concept

Philosophers conceptualized bullshit as persuasive communication that has no regard for truth, knowledge, or evidence. In psychology, research mostly investigated pseudo-profound bullshit, but no study has examined bullshit in the political context. In the present research, we operationalized political bullshit receptivity as endorsing vague political statements, slogans, and political bullshit programs. We investigated the relationship of these three measures with pseudo-profound bullshit, ideology (political ideology, support for neoliberalism), populism, and voting behavior. Three pre-registered studies conducted in early 2020 in the U.S., Serbia, and the Netherlands (total N = 534) yielded medium to high intercorrelations between political bullshit measures and pseudo-profound bullshit, and acceptable construct validity (hypothesized one-factor solution). A meta-analysis on these three studies showed that all political bullshit measures positively correlated with support for the free market, while only some positively correlated with social (political statements and programs) and economic conservatism (programs), and populism (programs). In the U.S., the Netherlands, and all countries combined, increased receptivity to political bullshit was associated with a higher probability to vote for right-wing candidates/parties (e.g., Trump in the U.S.). Overall, political bullshit receptivity showed to be a useful construct that opens avenues for research in broad and meaningless political communication.

A-182 Depression Symptoms Predict Neurocognitive Functioning Following Pediatric Traumatic Brain Injury in the Acute Recovery Phase

Abstract Objective: Pediatric Intensive Care Unit (PICU) survivors are at elevated risk for developing neurocognitive concerns. Lower premorbid abilities, pediatric traumatic brain injury (pTBI) severity, and post-injury depression symptoms have been shown to predict greater neurocognitive deficits. However, limited extant research has focused on the acute recovery phase or used objective neuropsychological assessment measures. We examined the impact of pTBI severity and post-injury depression symptoms on neurocognitive functioning in the acute recovery phase. Method: Seventy-four trauma patients (8 to 19 years) were assessed 1-3 months after PICU discharge. Demographic and clinical data were extracted from the electronic medical record. Caregivers completed questionnaires about their children’s physical, cognitive and emotional functioning. The direct assessment included measures of WRAT5 word-reading; CMS/WISC-V/WAIS-IV digit span; WISC-V/WAIS-IV coding and symbol search; and DKEFS Trails-4, verbal phonemic and semantic fluencies. Given the high intercorrelations between aspects of executive function, principal components analysis (PCA) was conducted to create a cumulative neurocognitive index (NCI). A simple linear regression was used to test if moderate-severe Glasgow Coma scores and clinically elevated Promis Depression scores predicted NCI, controlling for reading ability. Results: Combining all participant data in the PCA yielded a single component solution accounting for 52.79% of total explained variance. The overall regression was significant (R2=.40), F(df=3,70) =15.23, p&amp;lt;.001. Elevated depression predicted NCI (p=.03) whereas greater pTBI severity was not predictive above the impact of premorbid factors. Conclusions: Neurocognitive functioning in PICU survivors within the acute recovery phase may be more related to concurrent depression symptoms than injury severity markers when premorbid factors are considered.

Structural parameter interdependencies in computational models of cognition.

Computational modeling of cognition allows latent psychological variables to be measured by means of adjustable model parameters. The estimation and interpretation of the parameters are impaired, however, if parameters are strongly intercorrelated within the model. We point out that strong parameter interdependencies are especially likely to emerge in models that combine a subjective value function with a probabilistic choice rule-a common structure in the literature. We trace structural parameter interdependencies between value function and choice rule parameters across several prominent computational models, including models on risky choice (cumulative prospect theory), categorization (the generalized context model), and memory (the SIMPLE model of free recall). Using simulation studies with a generic choice model, we show that the accuracy in parameter estimation is hampered in the presence of high parameter intercorrelations, particularly the ability to detect group differences on the parameters and associations of the parameters with external variables. We demonstrate that these problems can be alleviated by using a different specification of stochasticity in the model, for example, by assuming parameter stochasticity or a constant error term. In addition, application to two empirical data sets of risky choice shows that alleviating parameter interdependencies in this way can lead to different conclusions about the estimated parameters. Our analyses highlight a common but often neglected problem of computational models of cognition and identify ways in which the design and application of such models can be improved. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Development of a Sexual Quality of Life Questionnaire for Men-Who-Have-Sex-With-Men With Prostate Cancer.

BackgroundProstate cancer (PCa) is often diagnosed early with prolonged survival, which makes sexual quality of life (QoL) an increasingly important treatment consideration, but existing QoL questionnaires have limited applicability for men who-have-sex-with-men (MSM) beyond penile erections and penetrative sex.AimWe aimed to create a validated survey instrument for assessing a variety of sexual activities beyond penile insertive sex for MSM after PCa treatment.MethodsBased on our previously published survey findings, we have generated a prototype questionnaire with 13 different domains, reviewed by both healthy MSM and pilot-tested by MSM treated for PCa.OutcomesWe report here on progress in developing the questionnaire and demonstrate the complexity of MSM sexual side effects resulting from PCa treatment(s).ResultsStatistical analysis of 204 responses from MSM treated for PCa showed that each domain performed well individually (Cronbach's alpha coefficients ranged from 0.80 to 0.95; item-total correlations ranged from 0.16 to 0.89), with many significant intercorrelations between the domains (ranged from -0.048 to 0.93).Clinical ImplicationsThe questionnaire can contribute to clinical diagnosis and treatment decisions that best fit the preferred sexual practices of individual MSM.Strengths & LimitationsThe current questionnaire considers a much broader repertoire of MSM's sexual practices and preferences than other currently available questionnaires. The high intercorrelations between the many parameters demonstrate that problems in one domain can affect other domains. This preliminary analysis warrants further exploration with a larger sample size.ConclusionsOnce validated our questionnaire should help develop tailored psychosocial supports for MSM experiencing sexual dysfunction after PCa treatment and help newly diagnosed MSM with PCa make treatment decisions informed by their preferred sexual practices.Wibowo E, Dowsett GW, Nelson CJ, et al. Development of a Sexual Quality of Life Questionnaire for Men-Who-Have-Sex-With-Men With Prostate Cancer. Sex Med 2022;10:100480.

Evaluation of Activated Carbon Treatment on Overcoming the Interference of Rivaroxaban on the Detection of Functional Lupus Anticoagulant

Objective: The aim of this study was to review the role of activated carbon (AC) in eliminating the interference of rivaroxaban in the detection of lupus anticoagulants (LAs). Methods: Normal pooled plasma was obtained as group N1, group N2 took 1 mL plasma from N1 and added AC, group N3 was prepared by mixing normal plasma with rivaroxaban, and group N3 was treated with AC according to our procedure, as group N4. Plasma from 22 patients was collected before and 6–12 h after rivaroxaban therapy, described as group P1 and group P2, respectively, and 1 mL plasma was taken from group P2 and treated with AC, as group P3. Anti-Xa and diluted Russell’s viper venom time (dRVVT)/silica clotting time (SCT) index in each group were measured and compared. Results: Rivaroxaban concentrations and anti-Xa had high intercorrelations in group N3, and the levels of anti-Xa and dRVVT/SCT index had high intercorrelations. After treatment with AC, influence of rivaroxaban was removed, with LA and coagulation factor assays not influenced. Rivaroxaban administration could affect LA assay results in patients, with all LA results increased. After treatment with AC, results of anti-Xa and LA tests recovered to the level before rivaroxaban therapy. Conclusions: We proposed a reference procedure for the LA detection of patients using rivaroxaban by AC, and activated carbon was proven to be a simple product to eliminate the interference of rivaroxaban.

Адаптация русскоязычной версии опросника «Учебный интерес и академическая самооценка»

Introduction. Motivation is one of the most reliable predictors of success in school, confirmed by the results of meta-analyses controls for intelligence and previous academic achievements. Goals and objectives. This article gives the results of the adaptation of the Russian version of the self-reported questionnaire, “Intrinsic motivation and Ability of self-perception”. It was aimed at measuring two aspects of a student's motivational sphere: their desire to study certain academic disciplines and self-assessment of their educational achievements in certain subjects at school. The age range analyzed was primary and secondary school children. Materials and methods. The questionnaire “Intrinsic motivation and Ability of selfperception” is aimed at measuring the motivation to study such school subjects as the Russian language, mathematics, natural sciences and physical education. The study involved 936 students aged 8 to 16.9 years, 396 primary school children (grades 2-4, 52.3% boys) and 540 adolescents (grades 5-9, 50.9% boys). Confirmatory factor analysis (CFI) and Student's t test were used. Results. According to the analyses of the original model, intrinsic motivation and selfperceptions of achievements factors for each school discipline had very high intercorrelations, which pointed towards a common latent construct underlying both intrinsic motivation and self-assessment of educational achievements. The study reveals differences in learning motivation between primary schoolchildren and adolescents in all analyzed school disciplines. Additionally observed was the tendency towards weakening of interrelationships between scores for learning motivations of various school disciplines in the period from primary to basic school education. Conclusion. Thus, the results of the adaptation of the Russian-language version of the “Intrinsic motivation and Ability of self-perception” questionnaire confirmed the four-factor structure, according to which there is a single indicator of academic motivation for each of the four school disciplines - the Russian language, mathematics, natural sciences and physical education.

Verification of the metric properties of E. E. Gordon’s Advanced Measures of Music Audiation among non-music major students in Croatia

The aim of the study was to investigate the metric properties of the Advanced Measures of Music Audiation test by E. E. Gordon (1989) on a sample of nonmusic major students in Croatia. The study was conducted with female students of early and preschool education at the Faculty of Education in Osijek (N = 235). The descriptive indicators of the AMMA test and the normality of the distribution of scores in the Croatian sample do not differ from the results obtained during the standardization on the American sample and the Polish sample of nonmusic major students. It was found that the reliability coefficient of the AMMA test, calculated using the split-half technique, was 0.87, and high intercorrelation values were obtained between the Total test and the Tonal (r = 0.88) and Rhythm (r = 0.87) subtests. Lower values of the difficulty level and discrimination power (&amp;lt; 0.20) are the weakest features of the application of the AMMA test to the Croatian sample. Considering the overall observed metric properties, it can be concluded that the AMMA test is a reliable measurement tool for the assessment of auditory musical abilities in nonmusic major students in Croatia.

ANTHROPOMETRICAL CHARACTERISTICS STRUCTURE TO THE 16-YEAR-OLD MALE STUDENTS

&lt;p&gt;The aim of the study is to determine the structure of some anthropometrical characteristics of children aged 16, living in Kosovo. The research was conducted on a sample of 110 male students of high school “Fehmi Lladrovci” in Gllogoc, the Republic of Kosovo. The sample of variable held eighteen anthropometric measures: four variables to estimate the dimensionality of the longitudinal skeleton, four variables to estimate the dimensionality of the transversal skeleton, four variables to estimate the volume of the body, four variables to estimate the skin folds of the body, body weight, and body mass index. The calculation of the data was made by using the SPSS 24 program. All morphological indicators have displayed different parameters that ranged from the lowest to the highest levels. The correlation analysis show that the coefficients of morphological variables are curved and appear as a homogeneous group with a high intercorrelation at the coefficient level of (p =0.01). Factor analysis has shown three latent factors, the first latent factor that has appeared is the anthropometric factor composed of longitudinal dimensionality, transversal dimensionality and body perimeter factors of skeleton. The second latent factor is composed of the skin folds, and the third factor is the anthropometric factor composed of body weight and body mass index.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/edu_01/0998/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Simultaneous Determination of 6 Antiretroviral Drugs in Human Hair Using an LC-ESI+-MS/MS Method: Application to Adherence Assessment.

The determination of antiretroviral drugs in hair is receiving considerable research interest to assess long-term adherence to antiretroviral therapy (ART). Currently in China, lamivudine, zidovudine, nevirapine, efavirenz, ritonavir, and lopinavir are combined as first-line and second-line free therapy regimens and are recommended for people living with HIV (PLWH). Simultaneous determination of the 6 antiretroviral drugs in human hair is important for accurately and widely assessing long-term adherence in Chinese PLWH receiving different ART regimens. Six drugs were extracted from 10-mg hair samples incubated in methanol for 16 hours at 37°C and then analyzed by liquid chromatography with tandem mass spectrometry using a mobile phase of 95% methanol, with an electrospray ionization source in multiple reaction monitoring and positive mode. The LC-ESI+-MS/MS method exhibited a linear range (R2 > 0.99) within 6-5000, 10-5000, 6-50,000, 12-50,000, 8-5000, and 8-12,500 pg/mg for lamivudine, zidovudine, nevirapine, efavirenz, ritonavir, and lopinavir. For all 6 drugs, the limits of quantification ranged between 6 and 12 pg/mg. The intraday and interday coefficients of variation were within 15%, and the recoveries ranged from 91.1% to 113.7%. Furthermore, the other validation parameters (ie, selectivity, matrix effect, stability, and carryover) met the acceptance criteria stipulated by guidelines of the US Food and Drug Administration and European Medicines Agency. Significant intergroup differences were observed between high-adherence and low-adherence groups, with high intercorrelations in the hair content of the 6 drugs. The developed method demonstrated good reliability, to comprehensively and accurately assess adherence in PLWH receiving different ART regimens.

Dietary intake of tocopherols and risk of incident disabling dementia

Tocopherols, strong antioxidants, may be useful in preventing dementia, but the epidemiological evidence is insufficient. We performed a community-based follow-up study of Japanese, the Circulatory Risk in Community Study, involving 3739 people aged 40–64 years at baseline (1985–1999). Incident disabling dementia was followed up from 1999 through 2020. For subtype analysis, we classified disabling dementia into that with and that without a history of stroke. Dietary intake of tocopherols (total, α, β, γ, and δ) were estimated using 24-h recall surveys. During a median follow-up of 19.7 years, 670 cases of disabling dementia developed. Total tocopherol intake was inversely associated with risk of disabling dementia with multivariable hazard ratios (95% confidence intervals) of 0.79 (0.63–1.00) for the highest versus lowest quartiles of total tocopherol intake (P for trend = 0.05). However, the association was strengthened when further adjusted for α-linolenic acid intake (Spearman correlation with total tocopherol intake = 0.93), with multivariable hazard ratios of 0.50 (0.34–0.74) (P for trend = 0.001) but was weakened and nonsignificant when further adjusted for linoleic acid intake (Spearman correlation with total tocopherol intake = 0.92), with multivariable hazard ratios of 0.69 (0.47–1.01) (P for trend = 0.05). Similar but nonsignificant inverse associations were observed for α-, γ-, and δ-tocopherols but not for β-tocopherol. These results were similar regardless of the presence of a history of stroke. Dietary tocopherol intake was inversely associated with risk of disabling dementia, but its independent effect was uncertain owing to a high intercorrelation of α-linolenic linoleic acids with total tocopherol intake. Even with such confounding, a diet high in tocopherols may help prevent the onset of dementia.

Beta ridge regression estimators: simulation and application

The beta regression model is commonly used when analyzing data that come in the form of rates or percentages. However, a problem that may encounter when analyzing these kinds of data that has not been investigated for this model is the multicollinearity problem. It is well known that the maximum likelihood (ML) method is very sensitive to high inter-correlation among the explanatory variables. Therefore, this paper proposes some ridge estimators for the beta regression model to remedy the problem of instability of the traditional ML method and increase the efficiency of estimation. The performance of ridge estimators is compared to the ML estimator through the mean squared error (MSE) and the mean absolute error (MAE) criteria by conducting a Monte-Carlo simulation study and through an empirical application. According to the simulation and application results, the proposed estimators outperform the ML estimator in terms of MSE and MAE.

Mentored undergraduate operating room teaching during the orthopedic trauma curriculum-No evidence of gender differences.

In many surgical disciplines, the interest among medical students to pursue asurgical career decreases during their medical studies. The same goes for students after graduation. The aim of our cohort study was to evaluate the operating room (OR) experiences of medical students during our curriculum. Over the course of one year 217 senior year medical students were included in our study. All of them took part in our training program for senior year medical students, which consisted of a1-week clinical rotation including visits to the OR. We developed aLikert-scaled questionnaire, which was evaluated anonymously; free text answers were also possible. Prior to the analysis of the sex and age differences, we confirmed that the evaluation scale provided acoherent measure of the OR evaluation. As afirst proxy, we conducted aseries of Spearman correlations which revealed high intercorrelations between all of the six items of the questionnaire, r(154) = 0.53 to r(154) = 0.94, all p < 0.001. These high intercorrelations transferred into avery high consistency of the six questions that evaluate the OR teaching; Cronbach's α = 0.95. There was no main effect of sex, F (1,146) = 2.19, p = 0.141. However, there was amain effect of age, F (2,146) = 3.75, p = 0.026, indicating that older participants evaluated the OR teaching more positively. Finally, there was no correlation between sex and age group, F (2,146) < 1, indicating that the effect of age on the evaluation score was equally pronounced for female and male participants. The aim of this study was to answer the question how mentored OR teaching during the orthopedic trauma curriculum is evaluated by medical students, and whether there are gender-specific differences. For this purpose we prospectively evaluated senior year medical students over aperiod of 12months during the orthopedic trauma curriculum with questionnaires. The medical students rated the mentored OR visits mainly positive. Previously published literature as well as our presented data indicate that the interest of medical students in starting asurgical career can only be increased if negative influencing factors are reduced. This includes especially positive communication with medical students and in daily professional interaction.

Algorithmic jingle jungle: A comparison of implementations of principal axis factoring and promax rotation in R and SPSS

A statistical procedure is assumed to produce comparable results across programs. Using the case of an exploratory factor analysis procedure—principal axis factoring (PAF) and promax rotation—we show that this assumption is not always justified. Procedures with equal names are sometimes implemented differently across programs: a jingle fallacy. Focusing on two popular statistical analysis programs, we indeed discovered a jingle jungle for the above procedure: Both PAF and promax rotation are implemented differently in the psych R package and in SPSS. Based on analyses with 247 real and 216,000 simulated data sets implementing 108 different data structures, we show that these differences in implementations can result in fairly different factor solutions for a variety of different data structures. Differences in the solutions for real data sets ranged from negligible to very large, with 42% displaying at least one different indicator-to-factor correspondence. A simulation study revealed systematic differences in accuracies between different implementations, and large variation between data structures, with small numbers of indicators per factor, high factor intercorrelations, and weak factors resulting in the lowest accuracies. Moreover, although there was no single combination of settings that was superior for all data structures, we identified implementations of PAF and promax that maximize performance on average. We recommend researchers to use these implementations as best way through the jungle, discuss model averaging as a potential alternative, and highlight the importance of adhering to best practices of scale construction.