Bootstrap Test Research Articles

The Use of Wastewater Surveillance to Estimate SARS-CoV-2 Fecal Viral Shedding Pattern and Identify Time Periods with Intensified Transmission.

Wastewater-based surveillance is an important tool for monitoring the COVID-19 pandemic. However, it remains challenging to translate wastewater SARS-CoV-2 viral load to infection number, due to unclear shedding patterns in wastewater and potential differences between variants. We utilized comprehensive wastewater surveillance data and estimates of infection prevalence (i.e., the source of the viral shedding) available for New York City (NYC) to characterize SARS-CoV-2 fecal shedding pattern over multiple COVID-19 waves. We collected SARS-CoV-2 viral wastewater measurements in NYC during August 31, 2020 - August 29, 2023 ( N = 3794 samples). Combining with estimates of infection prevalence (number of infectious individuals including those not detected as cases), we estimated the time-lag, duration, and per-infection fecal shedding rate for the ancestral/Iota, Delta, and Omicron variants, separately. We also developed a procedure to identify occasions with intensified transmission. Models suggested fecal viral shedding likely starts around the same time as and lasts slightly longer than respiratory tract shedding. Estimated fecal viral shedding rate was highest during the ancestral/Iota variant wave, at 1.44 (95% CI: 1.35 - 1.53) billion RNA copies in wastewater per day per infection (measured by RT-qPCR), and decreased by ∼20% and 50-60% during the Delta wave and Omicron period, respectively. We identified around 200 occasions during which the wastewater SARS-CoV-2 viral load exceeded the expected level in any of 14 sewersheds. These anomalies disproportionally occurred during late January, late April - early May, early August, and from late-November to late-December, with frequencies exceeding the expectation assuming random occurrence ( P < 0.05; bootstrapping test). These estimates may be useful in understanding changes in underlying infection rate and help quantify changes in COVID-19 transmission and severity over time. We have also demonstrated that wastewater surveillance data can support the identification of time periods with potentially intensified transmission.

Distributed leadership, self-awareness, democracy, and sustainable development: towards an integrative model of school effectiveness

ABSTRACT This study aimed to examine the effects of school principals' distributed leadership behaviors and teachers’ self-awareness on school effectiveness through the mediating role of democratic practices and attitudes towards sustainable development in schools. Accordingly, an integrative model was created. The study data were analyzed using structural equation modeling and bootstrapping tests. The analysis results confirmed that organizational democracy played a prominent mediating role between school principals’ distributed leadership practices and teachers’ perceptions of school effectiveness. We also found evidence for the effects of school principals’ distributed leadership behaviors and teachers’ self-awareness on school effectiveness through the mediating role of teachers’ attitudes towards sustainable development. We concluded that school principals’ distributed leadership practices could enhance school effectiveness through teachers’ perceptions of organizational democracy and attitudes towards sustainable development in schools. Besides, a high-quality educational environment and school effectiveness could be promoted by increasing teachers’ self-awareness and attitudes towards sustainable development.

Testing for time‐varying nonlinear dependence structures: Regime‐switching and local Gaussian correlation

AbstractThis paper examines nonlinear and time‐varying dependence structures between a pair of stochastic variables, using a novel approach which combines regime‐switching models and local Gaussian correlation (LGC). We propose an LGC‐based bootstrap test for examining whether the dependence structure between two variables is equal across different regimes. We examine this test in a Monte Carlo study, where it shows good level and power properties. We argue that this approach is more intuitive than competing approaches, typically combining regime‐switching models with copula theory. Furthermore, LGC is a semi‐parametric approach, hence avoids any parametric specification of the dependence structure. We illustrate our approach using financial returns from the US–UK stock markets and the US stock and government bond markets, and provide detailed insight into their dependence structures.

Enhancing psychological well-being in college students: the mediating role of perceived social support and resilience in coping styles

BackgroundThe prevalence of depression among college students is higher than that of the general population. Although a growing body of research suggests that depression in college students and their potential risk factors, few studies have focused on the correlation between depression and risk factors. This study aims to explore the mediating role of perceived social support and resilience in the relationship between trait coping styles and depression among college students.MethodsA total of 1262 college students completed questionnaires including the Trait Coping Styles Questionnaire (TCSQ), the Patient Health Questionnaire-9 (PHQ-9), the Perceived Social Support Scale (PSSS), and the Resilience Scale-14 (RS-14). Common method bias tests and spearman were conducted, then regressions and bootstrap tests were used to examine the mediating effects.ResultsIn college students, there was a negative correlation between perceived control PC and depression, with a significant direct predictive effect on depression (β = -0.067, P < 0.01); in contrast, negative control NC showed the opposite relationship (β = 0.057, P < 0.01). PC significantly positively predicted perceived social support (β = 0.575, P < 0.01) and psychological resilience (β = 1.363, P < 0.01); conversely, NC exerted a significant negative impact. Perceived social support could positively predict psychological resilience (β = 0.303, P < 0.01), and both factors had a significant negative predictive effect on depression. Additionally, Perceived social support and resilience played a significant mediating role in the relationship between trait coping styles and depression among college students, with three mediating paths: PC/NC → perceived social support → depression among college students (-0.049/0.033), PC/NC→ resilience → depression among college students (-0.122/-0.021), and PC/NC → perceived social support → resilience → depression among college students (-0.016/0.026).ConclusionThe results indicate that trait coping styles among college students not only directly predict lower depression but also indirectly influence them through perceived social support and resilience. This suggests that guiding students to confront and solve problems can alleviate their depression.

Tests for almost stochastic dominance

We introduce a 2-dimensional stochastic dominance (2DSD) index to characterize both strict and almost stochastic dominance. Based on this index, we derive an estimator for the minimum violation ratio (MVR), also known as the critical parameter, of the almost stochastic ordering condition between two variables. We determine the asymptotic properties of the empirical 2DSD index and MVR for the most frequently used stochastic orders. We also provide conditions under which the bootstrap estimators of these quantities are strongly consistent. As an application, we develop consistent bootstrap testing procedures for almost stochastic dominance. The performance of the tests is checked via simulations and the analysis of real data.

The moderating effect of Social Support on the Relationship between Cultural Intelligence and Cross-Cultural Adjustment of Chinese Expatriates in Ghana

Literature shows that not all individuals are equally suited to embark on a new life in another country, and self-initiated expatriates (SIEs) could be particularly susceptible to failure since they have no support from a home organization. The study sought to examine the moderation role of Social Support in relation to Cultural intelligence (CQ) Cross-Cultural Adjustment of Chinese Self-initiated Expatriates (SIEs) in Ghana. A sample of 400 respondents was selected for the study. Questionnaires were used to collect data via an online survey. Data was analyzed using PLS-SEM for the analysis, PLS algorithms and Bootstrapping tests were performed. Findings suggested that social support acquired by Chinese SIEs from host country citizens had no moderating influence on the relationship between their CQ and their capacity to adapt cross culturally to Ghanaian cultural situations. The study's findings will help SIEs, human resource practitioners, and cross-cultural managers who work with SIEs to understand the requirements for effective cross-cultural management towards reducing expats failure.

A Prognostic Model Incorporating Relevant Peripheral Blood Inflammation Indicator to Predict Postherpetic Neuralgia in Patients with Acute Herpes Zoster.

To determine the risk of postherpetic neuralgia (PHN) in patients with acute herpes zoster (HZ), this study developed and validated a novel clinical prediction model by incorporating a relevant peripheral blood inflammation indicator. Between January 2019 and June 2023, 209 patients with acute HZ were categorized into the PHN group (n = 62) and the non-PHN group (n = 147). Univariate and multivariate logistic regression analyses were conducted to identify risk factors serving as independent predictors of PHN development. Subsequently, a nomogram prediction model was established, and the discriminative ability and calibration were evaluated using the receiver operating characteristic curve, calibration plots, and decision curve analysis (DCA). The nomogram model was internally verified through the bootstrap test method. According to univariate logistic regression analyses, five variables, namely age, hypertension, acute phase Numeric Rating Scale (NRS-11) score, platelet-to-lymphocyte ratio (PLR), and systemic immune inflammation index, were significantly associated with PHN development. Multifactorial analysis further unveiled that age (odds ratio (OR) [95% confidence interval (CI)]: 2.309 [1.163-4.660]), acute phase NRS-11 score (OR [95% CI]: 2.837 [1.294-6.275]), and PLR (OR [95% CI]: 1.015 [1.010-1.022]) were independent risk factors for PHN. These three predictors were integrated to establish the prediction model and construct the nomogram. The area under the receiver operating characteristic curve (AUC) for predicting the PHN risk was 0.787, and the AUC of internal validation determined using the bootstrap method was 0.776. The DCA and calibration curve also indicated that the predictive performance of the nomogram model was commendable. In this study, a risk prediction model was developed and validated to accurately forecast the probability of PHN after HZ, thereby demonstrating favorable discrimination, calibration, and clinical applicability.

Pengaruh Penerapan Remote Audit pada Kualitas Audit Internal Pasca Pandemi Covid-19

Despite the challenges encountered in the field, audit quality within the scope of internal audit remains a top priority. The study outlines the ways in how remote audits impact audit quality and the approaches implemented by internal auditors to enhance audit quality. Examining the effect of remote auditing on audit quality is appropriate given the COVID-19 pandemic. This combination of auditor competence and time budget pressure to moderate the effect of remote audits on internal audit quality are also addressed in this study. Survey data is used in this study to measure how far APIP in East Java Province began using remote auditing after the epidemic. SmartPLS is used in the analytical method combined with the Structural Equation Modeling (SEM) model such as reliability and convergent validity test, discriminant validity test and PLS path algorithm and bootstrapping test. The research questionnaire's are measured using a Likert scale (1-7). Remote audits have a positive effect on improving internal audit quality, according to the result of a survey conducted towards 76 out of 100 internal auditors. But auditor competence and time budget pressure does not significantly moderate such a relationship. The research's conclusions have significance for practitioners looking to improve audit quality in remote audits and may benefit users of financial reports to comprehend the level of audit quality in remote audits

Mediating Effect of Autonomy Support between Exercise Knowledge and Exercise Self-Efficacy of Patients with Severe Mental Illness

Purpose: This study aimed to explore how autonomy support mediates the association between exercise knowledge and exercise self-efficacy in patients with severe mental illness.Methods: A total of 181 individuals were selected through convenience sampling. They completed self-administered surveys measuring exercise knowledge, autonomy support, and exercise self-efficacy. The data analysis was conducted using descriptive statistics, t-tests, one-way analysis of variance, Pearson’s correlation coefficients, and multiple linear regression. To determine the statistical significance of the mediating effect, a bootstrapping test was also conducted.Results: This research revealed that autonomy support significantly predicted exercise self-efficacy and partially mediated the association between exercise knowledge and exercise self-efficacy (lower limit confidence interval [LLCI]: 2.34; upper limit confidence interval [ULCI]: 5.97). The model incorporating exercise knowledge and autonomy support explained 42.0% of the variance in exercise self-efficacy.Conclusion: Collaborative endeavors involving mental health practitioners and exercise experts demonstrate notable efficacy in enhancing exercise self-efficacy of individuals with mental illness.

IMPACT OF COP26 ON INDIAN STOCK INDICES: AN EVENT STUDY APPROACH

The study aims at measuring impact of Indian government commitment on ESG100 index and BSE Manufacturing Index of Bombay Stock Exchange. The study uses the Event sturdy approach to compare pre-event and post-event Abnormal return and cumulative abnormal return. The Bootstrapping and Wilcoxon tests has been used for comparison. There is no significant difference found in abnormal return of both of the index. Mean adjusted cumulative abnormal return of both of the index es has significant differences. In BSE ESG100 index, Market adjusted cumulative abnormal return has no significant difference. In BSE Manufacturing index, Mean adjusted cumulative abnormal return has significant difference. The carbon neutrality deadline is long away, so Indian investors do not consider CoP26 seriously.

Comparison and Empirical Evaluation of Classical Tests of Skewness versus Bootstrap Tests of Skewness

Comparison and Empirical Evaluation of Classical Tests of Skewness versus Bootstrap Tests of Skewness

A rank-based adaptive independence test for high-dimensional data

There are lots of methods for complete independence test for high-dimensional random vector. However, it is difficult for practitioners to choose a powerful test because the true alternative hypothesis is unknown. Combining the L 2-type with the L ∞ -type test statistic, we propose a rank-based test method. From a technical point of view, the proposed test is distribution-free and consequently the corresponding critical values or p-values can be obtained by Monte Carlo methods. Compared with permutation or bootstrap test methods, the proposed test method saves calculation cost. Simulation results show that the resulting method has excellent performance with finite sample size. We also provide a real data application to demonstrate the practicality and effectiveness of the proposed test method.

THE ROLE OF SELF EFFICACY IN IMPROVING EMPLOYEE PERFORMANCE SUPPORTED BY ORGANIZATIONAL CULTURE AND CAREER DEVELOPMENT

This study aims to find out the influence of organizational culture, career development development, and self-efficacy on employee performance. The population in this study is all employees of the Tirta Darma Ayu Indramayu Regional Drinking Water Company (PDAM) which totals 146 people, with a sample of 110 people. The method used in this study uses one of the saturated sampling techniques. To analyze the data, the use of Structural Equation Modeling (SEM) in model creation as well as hypothesis testing in PLS 3.0 statistical software. The two main parameters built are to test the validity of the construct (convergent and discriminatory validity) and the internal consistency of the construct (reliability). After that, perform bootstrapping tests to get the test results for each hypothesis. The results of this study show that the Self-efficacy Variable (X1) partially has a positive or significant effect on the performance of employees (Y) at the Indramayu Regional Drinking Water Company. The Organizational Culture Variable (X2) partially has a positive or significant effect on the performance of employees (Y) at the Indramayu Regional Drinking Water Company The Career Development Variable (X3) partially has a positive or significant effect on the performance of employees (Y) at the Indramayu Regional Drinking Water Company.

Bootstrap test procedure for variance components in nonlinear mixed effects models in the presence of nuisance parameters and a singular Fisher information matrix

Summary We examine the problem of variance component testing in general mixed effects models using the likelihood ratio test. We account for the presence of nuisance parameters, ie, the fact that some untested variances might also be equal to zero. Two main issues arise in this context, leading to a nonregular setting. First, under the null hypothesis, the true parameter value lies on the boundary of the parameter space. Moreover, due to the presence of nuisance parameters, the exact locations of these boundary points are not known, which prevents the use of classical asymptotic theory of maximum likelihood estimation. Then, in the specific context of nonlinear mixed effects models, the Fisher information matrix is singular at the true parameter value. We address these two points by proposing a shrunk parametric bootstrap procedure, which is straightforward to apply even for nonlinear models. We show that the procedure is consistent, solving both the boundary and the singularity issues, and we provide a verifiable criterion for the applicability of our theoretical results. We show through a simulation study that, compared to the asymptotic approach, our procedure has a better small sample performance and is more robust to the presence of nuisance parameters. A real data application on bird growth rates is also provided.

The mediating role of sleep disturbance in the relationship between depression and cardiovascular disease.

Studies suggest that both depression and disrupted sleep disturbance are linked to cardiovascular disease (CVD). However, the precise role of sleep disturbance in the connection between depression and CVD is poorly understood. Therefore, we sought to examine the associations among these factors and further explore the mediating role of sleep disturbance in the association between depression and CVD. This study included data from 29,831 adults (≥20 years old). Multifactorial logistic regression analyses were conducted to examine the relationships among depression, sleep disturbance, and CVD. Additionally, bootstrap tests were used to investigate whether the association between depression and CVD was mediated by sleep disturbance. Our research showed that individuals who experienced depression or sleep disturbance had a notably greater likelihood of developing CVD than those who did not have these issues (depression: OR: 2.21, 95% CI=1.96-2.49; sleep disturbance: OR: 1.74, 95% CI=1.6-1.9). Even after adjusting for potential confounders, depression was still positively associated with the risk of sleep disturbance (OR: 4.07, 95% CI=3.73-4.44). Furthermore, sleep disturbance significantly mediated the association between depression and CVD, with a mediating effect of 18.1%. Our study demonstrated that depression, sleep disturbance, and CVD are interrelated. The increased risk of CVD among patients with depression may be attributed to the mediating role of sleep disturbance. This finding underscores the importance of interventions focused on sleep disturbances as a means to address the connection between depression and CVD.

Functional repeated measures analysis of variance and its application

This paper is inspired by medical studies in which the same patients with multiple sclerosis are examined at several successive visits (doctor’s appointments) and described by fractional anisotropy tract profiles, which can be represented as f unctions. Since the observations for each patient are dependent random processes, they follow a repeated measures design for functional data. To compare the results for different visits, we thus consider functional repeated measures analysis of variance. For this purpose, a pointwise test statistic is constructed by adapting the classical test statistic for one-way repeated measures analysis of variance to the functional data framework. By integrating and taking the supremum of the pointwise test statistic, we create two global test statistics. In addition to verifying the general null hypothesis of the equality of mean functions corresponding to different objects, we also propose a simple method for post hoc analysis. We illustrate the finite sample properties of permutation and bootstrap testing procedures in an extensive simulation study. Finally, we analyze a real data example in detail. All methods are implemented in the R package rmfanova, available on CRAN.

Parenting styles and young children’s problem behaviours: the mediating role of electronic media usage

ABSTRACT To explore the relationships among parenting styles, children’s electronic media usage (EMU) and children’s problem behaviours (CPB), 1,224 preschoolers aged 3–6 years old (52.0% boys; 30.9% aged 3 years old, 34.6% aged 4 years old, 26.1% aged 5 years old, and 8.4% aged 6 years old) and their parents were enrolled in the present study by means of a questionnaire administered as an online survey, with the primary caregivers completing the questionnaires regarding parenting styles, strengths and difficulties, and time their preschoolers spent using electronic media. The results indicated that there is a significant two-by-two correlation among the three variables. The authoritative parenting style significantly and negatively predicted recreational e-activities (REA) and CPB and significantly and positively predicted educational e-activities (EEA). The authoritarian parenting style significantly and positively predicted REA and CPB and significantly and negatively predicted EEA. A further bootstrap test indicated that children's EMU partially mediated the relationship between parenting styles and CPB.

A dual mediation model of the association between principal inclusive leadership and teacher innovative behavior

Teacher innovation is crucial for the education system to adapt to contemporary society's evolving demands. However, the underlying mechanism of how inclusive leadership positively impacts employees’ innovative behavior remains incomplete. Therefore, drawing upon the social cognitive theory, this study aims to comprehensively examine the mediating effects of teachers’ psychological empowerment and school innovation climate on the relationship between inclusive leadership and innovative behavior among primary and junior teachers. A total of 358 valid questionnaires were administered to primary and junior teachers in mainland China using a convenience sampling approach. The data were analyzed using hierarchical linear modeling and bootstrap testing, revealing a positive relationship between principal inclusive leadership and teacher innovative behavior. Additionally, teachers’ psychological empowerment and school innovation climate were found to mediate this relationship, with the former playing a crucial role. The findings can enhance existing research on the impact of inclusive leadership in basic education. They also offer a new perspective for analyzing how inclusive leadership affects employees’ innovative behavior and provide valuable insights into stimulating innovation among primary and junior teachers.

Sleep quality mediates the effect of medical social support on depression symptoms in patients with HIV/AIDS

ObjectivesThe purpose of our study is to further understanding of the depression symptoms of HIV/AIDS patients in Guilin, Guangxi via exploring whether there is a mediating effect of sleep quality on medical-social support and depression symptoms and therefore provide a theoretical basis for application of medical-social support to alleviate depression symptoms of HIV/AIDS patients.MethodsA convenience sampling method was used to select 200 HIV/AIDS patients for the study. Depression symptoms, sleep quality, and medical-social support of the study participants were investigated using The Center for Epidemiological Studies Depression Scale (CES-D), The Pittsburg Sleep Quality Index (PSQI), and The Medical Outcomes Study Social Support Survey (MOS-SSS), respectively. Predictors of depression symptoms were explored by multiple linear regression, and Pearson correlation was used to analyze the relationship between sleep quality, medical-social support, and depression symptoms. Mediating effect analysis was performed by nonparametric Bootstrap test.ResultsIn this study, the incidence of depression symptoms was 54.4%. Multiple linear regression analysis showed that leanness (β = 0.161, P = 0.008), obesity (β = 0.186, P = 0.002), sleep quality score > 7 (β = 0.331, P < 0.001), and medical-social support score > 56 (β = -0.247, P < 0.001) could influence depression symptoms of HIV and Pearson’s correlation analysis demonstrated that there was a two-way correlation between sleep quality, medical social support and depression symptoms (P < 0.05). In addition, Bootstrap tests showed that medical-social support might affect depression symptoms not only directly but also indirectly through the mediating effect of sleep quality with the direct and mediating effects accounting for 77.25% and 22.75% of the total effect, respectively.ConclusionThe prevalence of depression symptoms is high among HIV/AIDS patients in Guilin City. The depressive symptoms of PLWHs(people living with HIV) are related to their sleep quality and medical-social support, and sleep quality partially mediates the relationship between medical-social support and depression symptoms. Therefore, interventions to improve sleep quality and medical-social support have the potential to allay the depression symptoms of HIV/AIDS patients.

Is the time of anthesis in rice (Oryza sativa) influenced by photoperiod?

Photoperiod sensitivity in rice cultivars is defined when the cultivar begins anthesis on a relatively invariant date, varying by < 7days, regardless of the date of sowing or germination. While the date of flowering in photoperiod sensitive (PPS) rice cultivars is characteristically determined by the day length, especially during the short-day season (September-December), the response of the flower opening time (FOT) to photoperiod remains hitherto unexplored. This paper examines whether day length restrains year-to-year variation in FOT in PPS cultivars. We examined 105 PPS and 173 photoperiod insensitive (PPI) cultivars grown in different years and estimated their year-to-year FOT difference (or FOTD) and the year-to-year difference of sunrise to anthesis duration (or SADD). Wilcoxon signed rank test and bootstrap test were then performed to test whether these descriptors significantly differed between PPS and PPI groups of cultivars. The means of FOTD and SADD were detected to be significantly less in the PPS group than in the PPI group of cultivars, indicating significantly lesser variability of FOT in PPS than in PPI cultivars. This is the first report of a strong restraining influence of photoperiod on FOT variability in PPS cultivars.