Covariate Variables Research Articles

The Effect of Presentation Variety of Interactive Multimedia Learning to the Learning Result

research aims to investigate the impact of many kinds of computer-based interactive multimedia learning presentation to the learning result by controlling the student's prior knowledge. The kinds of learning presentation consist of multimedia learning with high interactivity ((animation visualization + narration) and (static visualization + clue + narration)) and multimedia learning with low interactivity ((animation visualization + narration) and (static visualization + clue + narration)). The research method used quasi experimental approach, with the kinds of multimedia learning presentation act as independent variable with 4 kinds of treatment, the student's learning result as the dependent variable, and student's prior knowledge as the covariate variable. The research was conducted in STMIK STIKOM Bali with the research subject is the students of even semester 2013/2014, and the analysis method used the Covariance Analysis. Based on the analysis results, it can be concluded that by controlling the student's prior knowledge of high interactivity multimedia learning group (built by Adobe Flash) is more effective than the low interactivity multimedia learning group (built by PowerPoint and Screencast-O-Matic). Besides that, on the high interactivity multimedia learning group, the effectiveness of the visualization content through animation+narration is equal with the content visualization through static visualization+clue+narration. This condition is also applied with the low interractivity multimedia learning. Keywordslearning, animation, high interactivity, low interactivity, prior knowledge, learning result.

Robust estimation under heavy contamination using unnormalized models

Contamination caused by outliers is inevitable in data analysis, and robust statistical methods are often needed. In this paper we develop a new approach for robust data analysis on the basis of scoring rules. A scoring rule is a discrepancy measure to assess the quality of probabilistic forecasts. We propose a simple method of estimating not only parameters in the statistical model but also the contamination ratio, i.e., the ratio of outliers. The outliers are detected based on the estimated contamination ratio. For this purpose, we use scoring rules with extended statistical models called unnormalized models. Regression problems are also considered. We study complex heterogeneous contamination wherein the contamination ratio in a response variable may depend on covariate variables, and propose a simple method to estimate a robust regression function and expected contamination ratio. Simulation studies demonstrate the effectiveness of our method.

Estimation for Partially Linear Single-index Instrumental Variables Models

In this article, we generalize the partially linear single-index models to the scenario with some endogenous covariates variables. It is well known that the estimators based on the existing methods are often inconsistent because of the endogeneity of covariates. To deal with the endogenous variables, we introduce some auxiliary instrumental variables. A three-stage estimation procedure is proposed for partially linear single-index instrumental variables models. The first stage is to obtain a linear projection of endogenous variables on a set of instrumental variables, the second stage is to estimate the link function by using local linear smoother for given constant parameters, and the last stage is to obtain the estimators of constant parameters based on the estimating equation. Asymptotic normality is established for the proposed estimators. Some simulation studies are undertaken to assess the finite sample performance of the proposed estimation procedure.

A case study of the online coverage of the Christmas day Bombing Attempt in the New York Times

A mediation regression model has been constructed to analyze the New York Times ’online coverage of the Christmas Day Bombing Attempt and the related systemic failure. The test shows that the Daily employed frames as variables that explain why and how the systemic failure took place on December 25, 2009. The variables also identify which US agency affected the US security system, allowing the terror attempt to take place. The analysis illuminates that through the variable databases, there is significant indirect causal effect of the variable system on the variable failure, and this causal relationship goes under significant impact of two covariate variables, Central Intelligence Agency (CIA) and Department of State (DoS). According to the findings, framing projected by the New York Times ’website attributes 60% of the systemic failure to the CIA and the DoS.

A Varying-Coefficient Panel Data Model with Fixed Effects: Theory and an Application to U.S. Commercial Banks

In this paper, we propose a panel data semiparametric varying-coefficient model in which covariates (variables affecting the coefficients) are purely categorical. This model has two features: first, fixed effects are included to allow for correlation between individual unobserved heterogeneity and the regressors; second, it allows for cross-sectional dependence through a general spatial error dependence structure. We derive a semiparametric estimator for our model by using a modified within transformation, and then show the asymptotic and finite properties for this estimator. Finally, we illustrate our model by analyzing the effects of state-level banking regulations on the returns to scale of commercial banks in the U.S.. Our empirical results suggest that returns to scale is higher in more regulated states than in less regulated states.

The effect of dietary education on ADHD, a randomized controlled clinical trial.

BackgroundThe purpose of this research was to study the effectiveness of the overall dietary intervention rather than a single nutrient on children with attention deficit hyperactivity disorder (ADHD).MethodsThis is a randomized controlled trial conducted at a child psychiatry clinic in Iran. Participants were 106 children and adolescents with ADHD.One group received methylphenidate plus dietary recommendations, while the other group only received methylphenidate. ADHD DSM-IV checklist was used to assess inattentiveness and hyperactivity/impulsivity scores at baseline and at the end of the trial.ResultsThe results revealed no significant difference between the two groups regarding mean age, gender ratio, body mass index, baseline inattentiveness score, and baseline hyperactivity score. Linear regression analysis considering the covariant variables showed that the inattentive score at the end of the trial was significantly associated with the mean change of favorite diet scores.ConclusionThis is the first clinical trial examining the effect of overall dietary characteristics rather than a single nutrient on the children formally diagnosed with ADHD. According to the results, un-favorite diet had no effects on inattentive or hyperactivity/impulsivity score. Encouraging the children with ADHD to increase their intake of recommended diet markedly improves their attention.Trial registrationThe trial was registered at the Iranian Clinical Trials Registry (Irct ID: IRCT201311303930N29).

Effects of High-Sugar and High-Starch Diets on Postprandial Inflammatory Protein Concentrations in Horses

Mature, nonpregnant, Thoroughbred mares were used to determine the influence of high-starch and high-sugar diets on postprandial inflammation. Plasma samples were obtained hourly from mares (n = 12) consuming one of two treatment diets, either a diet high starch and sugar (STR) or the control (CON) diet that was low in starch and sugar. Plasma was analyzed for concentrations of lipopolysaccharide (LPS) and the inflammatory cytokines interleukin (IL)-1β and IL-6. Hour 0 was included as a covariate in the statistical model, and where interactions between the covariate and other model variables existed, simple effect means were separated at three levels of the covariate: lower 95% confidence limit (CL), mean, and upper 95% CL. For horses with low (P = .016) and average (P = .065) initial LPS concentrations, LPS was greater or tended to be greater in STR compared with CON at hour 2 after feeding. No other differences were detected for LPS concentrations. For horses with low (P = .037), average (P = .006), and high (P = .001) initial IL-1β concentrations, plasma IL-1β was greater in STR than CON at hour 2 after feeding. For horses with high initial IL-1β concentrations, IL-1β also tended to be greater at hour 3 (P = .077). For horses with low (P = .022) or average (P = .063) initial IL-6 concentrations, IL-6 was greater or tended to be greater at hour 1 than 0. No effect of diet was detected for horses that started with high initial IL-6 concentrations. High-starch and high-sugar diets increase postprandial IL-1β concentrations, and it is likely that this effect is independent of LPS.

Deformations of special geometry: in search of the topological string

The topological string captures certain superstring amplitudes which are also encoded in the underlying string effective action. However, unlike the topological string free energy, the effective action that comprises higher-order derivative couplings is not defined in terms of duality covariant variables. This puzzle is resolved in the context of real special geometry by introducing the so-called Hesse potential, which is defined in terms of duality covariant variables and is related by a Legendre transformation to the function that encodes the effective action. It is demonstrated that the Hesse potential contains a unique subsector that possesses all the characteristic properties of a topological string free energy. Genus $g\leq3$ contributions are constructed explicitly for a general class of effective actions associated with a special-K\"ahler target space and are shown to satisfy the holomorphic anomaly equation of perturbative type-II topological string theory. This identification of a topological string free energy from an effective action is primarily based on conceptual arguments and does not involve any of its more specific properties. It is fully consistent with known results. A general theorem is presented that captures some characteristic features of the equivalence, which demonstrates at the same time that non-holomorphic deformations of special geometry can be dealt with consistently.

Forest protection and tenure status: The key role of indigenous peoples and protected areas in Panama

Using recent land cover maps, we used matching techniques to analyze forest cover and assess effectiveness in avoiding deforestation in three main land tenure regimes in Panama, namely protected areas, indigenous territories and non-protected areas. We found that the tenure status of protected areas and indigenous territories (including comarcas and claimed lands) explains a higher rate of success in avoided deforestation than other land tenure categories, when controlling for covariate variables such us distance to roads, distance to towns, slope, and elevation. In 2008 protected areas and indigenous territories had the highest percentage of forest cover and together they hosted 77% of Panama's total mature forest area. Our study shows the promises of matching techniques as a potential tool for demonstrating and quantifying conservation efforts. We therefore propose that matching could be integrated to methodological approaches allowing compensating forests’ protectors. Because conserving forest carbon stocks in forested areas of developing countries is an essential component of REDD+ and its future success, the discussion of our results is relevant to countries or jurisdictions with high forest cover and low deforestation rates.

Conservation laws in gravity: A unified framework

We study general metric-affine theories of gravity in which the metric and connection are the two independent fundamental variables. In this framework, we use Lagrange--Noether methods to derive the identities and the conservation laws that correspond to the invariance of the action under general coordinate transformations. The results obtained are applied to generalized models with nonminimal coupling of matter and gravity, with a coupling function that depends arbitrarily on the covariant gravitational field variables.

Validity of a Residualized Dependent Variable After Pretest Covariance Adjustments: Still the Same Variable?

The authors empirically examined whether the validity of a residualized dependent variable after covariance adjustment is comparable to that of the original variable of interest. When variance of a dependent variable is removed as a result of one or more covariates, the residual variance may not reflect the same meaning. Using the pretest–posttest design as a general framework, the authors compared the nomological validity network for the (a) original dependent variable scores and (b) residualized dependent variable scores after having covaried-out variance explainable by a pretest. Heuristic and empirical examples are provided that demonstrate potential variation in construct validity of residualized dependent variables is a function of correlations among dependent, covariate, and validity variables.

Can Anatomical Morphomic Variables Help Predict Abdominal Injury Rates in Frontal Vehicle Crashes?

Objective: Abdominal injuries resulting from vehicle crashes can be significant, in particular when undetected. In this study, abdominal injuries for occupants involved in frontal impacts were assessed using crash and medical data.Methods: Injury rates and patterns were first assessed with respect to thoracic injuries. A statistical analysis was then conducted to predict abdominal injury outcome using 18 covariate variables, including 4 vehicle, 4 demographic, and 10 morphomic, derived from computed tomography (CT) scans. More than 260,000 logistic regression models were fitted using all possible variable combinations. The models were ranked using the Akaike information criterion (AIC) and combined through the model-averaging approach to produce the optimal predictive model. The performance of the models was then assessed using the area under the curve (AUC).Results: The rate of serious thoracic injury was 2.49 times higher than the rate of abdominal injury. The associated odds ratio was 2.31 (P <.01). These results suggest a strong association between serious abdominal and thoracic injuries.The optimal model AUC was 0.646 when using solely vehicle data, 0.696 when combining vehicle and demographic data, 0.866 when combining vehicle and morphomic data, and 0.879 when combining vehicle, demographic, and morphomic data. These results suggest that morphomic variables better predict abdominal injury outcomes than demographic variables. The most important morphomics variables included visceral fat area, trabecular bone density, and spine angulation.Conclusion: This study is the first to combine vehicle, demographic, and anatomical data to predict abdominal injury rates in frontal crashes.

The Possible Impact of Problem-solving Method of Instruction on Exceptional Students’ Creativity

The current study aimed at investigating the possible impact of the problem-solving method of instruction on the exceptional students’ creativity. A sample of 50 male exceptional (Mild intellectual disability) students studying in the third grade of junior high school was chosen and divided into two equal groups. Both groups filled out the Torrance Test of Creative Thinking (TTCT) in pre- and post-test stages. They also completed the Raven Standard Progressive Matrices (RSPM) as a covariate variable. The results of covariance analysis revealed that the mean value for creativity score was higher for the students provided with the problem-solving method of instruction than that of their counterparts provided with the traditional method of instruction while the effect of intelligence was controlled. The scores obtained for the factors including fluency, flexibility, originality, and elaboration also increased through problem-solving method of instruction.

Sarcopenia and falls in community-dwelling elderly subjects in Japan: Defining sarcopenia according to criteria of the European Working Group on Sarcopenia in Older People

This study assessed the association between sarcopenia (using the definition of the European Working Group on Sarcopenia in Older People) and fall in the past year among community-dwelling Japanese elderly. Subjects were 1110 community-dwelling Japanese aged 65 or older. We used bioelectrical impedance analysis (BIA) to measure muscle mass, grip strength to measure muscle strength, and usual walking speed to measure physical performance in a baseline study. “Sarcopenia” was characterized by low muscle mass and low muscle strength or low physical performance. “Presarcopenia” was characterized only by low muscle mass. Subjects who did not have any of these deficiencies were classified as “normal.” We then administered a questionnaire assessing age, sex, household status, chronic illness, lifestyle-related habits, and fall. This study showed the prevalence of fall was 16.9% and 21.3% in men and women, respectively, while that of sarcopenia was 13.4% and 14.9% in men and women, respectively. In men and women, the prevalence of sarcopenia was higher among those who had fallen. A logistic regression analysis using age, body fat, current drinker status, and physical inactivity for men, and age, body fat, smoking, and diabetes for women as covariate variables revealed that sarcopenia was significantly associated with a history of fall. The odds ratio for fall in the sarcopenia group relative to the normal group was 4.42 (95%CI 2.08–9.39) in men and 2.34 (95%CI 1.39–3.94) in women. This study revealed sarcopenia to be associated with falling in elderly Japanese. Sarcopenia prevention interventions may help prevent falls among elderly individuals.

Personal and Professional Discord: Examining Religious Conservatism and Lesbian‐, Gay‐, and Bisexual‐Affirmative Counselor Competence

Lesbian, gay, and bisexual (LGB) orientations can evoke strong reactions that are often based on personal beliefs that seemingly conflict with professional standards calling for LGB‐affirmative counseling. This study examined the relationship between religious conservatism and LGB‐affirmative counselor competence. Controlling for education level, political conservatism, and LGB interpersonal contact, the results indicate that, as religious conservatism increased, LGB competency significantly decreased. The strongest predictor of LGB‐affirmative counselor competency was religious fundamentalism, whereas multicultural course work was not a significant predictor.

Association of heme oxygenase-1 with the risk of polycystic ovary syndrome in non-obese women

Is circulating heme oxygenase-1 (HO-1) associated with the risk of polycystic ovary syndrome (PCOS)? Lower circulating HO-1 is associated with a higher risk of PCOS in non-obese women, in a dose-related manner. PCOS is one of the most common endocrine disorders in women of reproductive age, with increasing worldwide incidence. HO-1 plays a crucial role in many physiological systems, with potent anti-inflammatory, antioxidant and antimetabolic properties. This hospital-based case-control study included 80 women with PCOS and 80 healthy control women seen at the Reproductive Center of Tongji Hospital (Wuhan, China) from November 2011 to May 2012. Cases and controls were frequency-matched on age and BMI and were enrolled into the study once written informed consent had been obtained. Serum hormones, glucose, insulin and lipid concentrations were measured using an automated platform. Correlation coefficients and multiple linear regression models were calculated in the combined group (both cases and controls) using serum HO-1 concentration as the independent variable and age and BMI as covariate variables to explore the association between HO-1 and the pathophysiology of PCOS. To examine the independent association of serum HO-1 levels with the likelihood of PCOS, multivariate logistic analysis was used. The strength of the association was tested further by receiver-operating characteristic (ROC) curve models, with or without the addition of HO-1. Compared with controls, women with PCOS were found to have significantly increased insulin resistance (IR), oxidative stress (OS) and inflammation levels, creating a vicious circle of effects in the pathophysiology of PCOS. However, serum HO-1 was negatively associated with this vicious circle. Women with the highest tertile of HO-1 (≥5.29 ng/ml) had an odds ratio (OR) of PCOS of 0.02 (95% CI 0.0034-0.07) compared with women with the lowest quartile (<3.14 ng/ml) (P < 0.01). This trend remained after adjustment for potential confounders in the multivariable model (all P < 0.01). ROC analysis based on an existing prognostic model yielded significantly discriminative values for PCOS, with or without the addition of HO-1 (areas under the curves were 0.86 (95% CI 0.81-0.92) versus 0.95 (95% CI 0.92-0.98); P for difference = 0.0005). It is difficult to establish a time-integrated measure of circulating HO-1 during the progression of PCOS and these findings should be confirmed in large-scale studies involving different ethnic groups. Moreover, the study lacks measurements of glycated hemoglobin (HbA1c) to provide an index of blood glucose concentrations over time. Circulating HO-1 that provides protection against IR, OS and chronic inflammation is markedly reduced in non-obese women with PCOS. Low serum HO-1 is suggested as an independent risk factor for PCOS; thus, circulating HO-1 levels may be a novel biomarker for PCOS in young, non-obese women. This work was supported by grants from the National Natural Science Foundation of China (81202210) and the National Science and Technology Support Program of China (2012BAI02B02). None of the authors has any conflict of interest to declare.

High red blood cell distribution width is closely associated with nonalcoholic fatty liver disease

The red blood cell distribution width (RDW) has been reported to be a risk marker of morbidity and mortality for cardiovascular diseases in various study populations. Nonalcoholic fatty liver disease (NAFLD) is also a risk factor for cardiovascular diseases. However, the relationship between RDW and NAFLD is less certain. RDW was determined using a Coulter counter together with the hemoglobin level in 1637 normal control individuals and 619 NAFLD patients who were consecutively referred by general practitioners for routine medical check-up. The total plasma cholesterol, plasma triglyceride, and fasting glucose were determined using a multichannel analyzer, and BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), and the incidence of hypertension and coronary artery disease were measured using statistical analysis. Patients with NAFLD had a higher RDW, BMI, waist to hip ratio, SBP and DBP, fasting glucose, triglycerides, and hypertension incidence (P<0.01), and were also younger (P<0.01). NAFLD was considered as a dependent variable, whereas age, sex, BMI, waist to hip ratio, RDW, hemoglobin, SBP and DBP, fasting glucose, total cholesterol, triglyceride, and hypertension were considered as covariate variables. We found that age (β=-0.031, P<0.01), BMI (β=0.265, P<0.01), waist to hip ratio (β=6.166, P<0.01), RDW (β=0.154, P<0.01), fasting plasma glucose (β=0.301, P<0.01), and triglyceride (β=0.222, P<0.01) were significantly associated with the risk for NAFLD, analyzed by binary logistic regression analysis. Patients with NAFLD were more likely to have high levels of RDW. Moreover, NAFLD was associated with age, BMI, RDW, fasting plasma glucose, and triglyceride. If confirmed in future follow-up studies, this association might provide a rationale to introduce the easy, inexpensive RDW in algorithms for NAFLD risk prediction.

A Comparative Study of the Effect of Computer-based Instruction and Problem-solving Instruction on the Students’ Creativity

The current study aimed to identify the appropriate method of teaching creativity through comparing computer-based instruction with problem-solving instruction. A sample of 50 male students studying in the second grade of junior high school was chosen and divided into two equal groups. Both groups filled out the Torrance Test of Creative Thinking (TTCT) in pre- and post-test stages. They also completed the Raven Standard Progressive Matrices (RSPM) as a covariate variable. The results of covariance analysis revealed that the mean value for creativity score was higher for the students provided with the computer-based method of instruction than that of their counterparts provided with the problem-solving method of instruction while the effect of intelligence was controlled. The scores obtained for the fluency component of creativity and those for flexibility, originality, and elaboration components also increased more through problem-solving and computer-based method of instruction, respectively. To sum up, employing computer-based method of instruction resulted in a further increase in the students’ creativity.

Frailty among rural elderly adults

BackgroundThis study aimed to estimate the prevalence and associated factors related to frailty, by Fried criteria, in the elderly population in a rural area in the Andes Mountains, and to analyze the relationship of these with comorbidity and disability.MethodsA cross-sectional study was undertaken involving 1878 participants 60 years of age and older. The frailty syndrome was diagnosed based on the Fried criteria (weakness, low speed, low physical activity, exhaustion, and weight loss). Variables were grouped as theoretical domains and, along with other potential confounders, were placed into five categories: (a) demographic and socioeconomic status, (b) health status, (c) self-reported functional status, (d) physical performance-based measures, and (e) psychosocial factors. Chi-square, ANOVA, and multinomial logistic regression analyses were used to test the prognostic value of frailty for the outcomes of interest.ResultsThe prevalence of frailty was 12.2%. Factors associated with frailty were age, gender, health status variables that included self-perceived health and number of chronic conditions, functional covariate variables that included disability in activities in daily living (ADL), disabilities in instrumental ADL, chair stand time, and psychosocial variables that included depressive symptoms and cognitive impairment. Higher comorbidity and disability was found in frail elderly people. Only a subset of frail elderly people (10%) reported no disease or disability.ConclusionsA relevant number of elderly persons living in rural areas in the Andes Mountains are frail. The prevalence of frailty is similar to that reported in other populations in the Latin American region. Our results support the use of modified Cardiovascular Health Study criteria to measure frailty in communities other than urban settings. Frailty in this study was strongly associated with comorbidities, and frailty and comorbidity predicted disability.

不同林分起源的相容性生物量模型构建

Biomass equations for individual-trees have appeared frequently in the ecological and forestry literature over the last 60 years as biomass estimation is a prerequisite for studies on forest productivity,nutrient cycling and for calculating carbon sequestration,storage and other structural and functional attributes of forest ecosystems. Over the same period of time,the methods of developing biomass equations for total tree and component biomass have evolved from single equation least squares to multivariate adjustment in proportion and simultaneous equations,both linear and nonlinear. The single equation approach relates total tree biomass and its components such as stem,wood,bark,branches,and foliage to predictor variables such as diameter at breast height,height and sometime also crown width using log transformed data through least squares regression. The equation for each component is estimated separately without taking into account( 1) the inherent correlation among the biomass components measured on the same sample trees and( 2) the logical constraint between the sum of predicted biomass for tree components and the prediction for the total tree. As a result,biomass equations developed through this approach fall short of statistical efficiency in parameter estimation and lack compatibility among the component equations( Parresol 1999). The lack of compatibility means inconsistency in logic in the sense that the predicted values from summing the biomass equations of tree components do not equal to the predicted value from theequation for the total tree biomass. Development of compatible individual-tree biomass models were well reported in the literature,while how to construct these biomass models for trees from different stand origin has not been investigated so far. In this paper,generalized models on total above-ground biomass and its four components( stem wood,stem bark,branch, and foliage) for trees from different stand origin were established using the methods of adjustment in proportion and nonlinear simultaneous equations. Totally 150 Masson pine( Pinus masson iana) trees were sampled for biomass investigation in southern China. For the two approaches mentioned above,i. e. adjustment in proportion and nonlinear simultaneous equations,controlling jointly from level to level by ratio functions and controlling directly under total biomass by proportion functions were employed. Covariate variables of one-,two- and three-variable biomass models were obtained from five stand variable candidates of diameter at breast height,tree total height,diameter at ground level,height to crown base and crown width. Weighted least square regression was used to remove the heteroscedasticity of biomass models. The results showed that both methods of adjustment in proportion and nonlinear simultaneous equations could efficiently ensure that the total biomass is equal to the summary of its components with high prediction accuracy. However,the prediction accuracy of nonlinear simultaneous equations was generally much higher than that of adjustment in proportion. The approach of controlling directly by proportion functions was slightly better than the one controlling jointly by ratio functions. The function of each component biomass itself as weighted function could remove heteroscedasticity effectively. The biomass models for each component with three variables( diameter at breast height,height and crown width) had the highest prediction accuracy,following by the two variables( diameter at breast height and height),and the single variable( diameter at breast height) model. The discrepancies among the models were very small,however. For balancing the model prediction accuracy and survey cost in constructing biomass model for trees from different stand origin,we suggest adapting the nonlinear simultaneous equations of controlling directly under total biomass with diameter at breast height and height as covariables.