MULTIVARLYTE ANALYSIS OF CLUSTERED SURVEY DATA: TESTING EQUALITY OF COVARLANCE MATRICES

The problem of testing the hypothesis of equality of covariance matrices in the presence of two-stage sampling is considered. Asymptotic test procedures based on linearization, grouping and jackknifing with or without transformation are proposed. The finite sample properties of these procedures are investigated in sampling experiments both from simulated known distributions and from a natural population.     

A Study of the Relationship Between Innovation and Performance Among NPOs in Pakistan

Abstract

Innovation has become a core driver for the success and survival of organizations regardless of their size and nature. A plethora of literature has discussed the importance of innovation in profit-based organizations, while nonprofit organizations (NPOs) have generally been ignored in research. This study examines the influence of the sub-dimensions of innovation on the performance of NPOs. Data were collected through structured questionnaires using a sample size of 309 NPOs operating in the emerging market Pakistan. The hypotheses were tested through structural equation modeling (SEM) in AMOS.21. The results indicate that process innovation and organization innovation have significant positive influence on the performance of NPOs, while product innovation and marketing innovation have insignificant influence on the performance of NPOs. NPOs are advised to give enough attention to process and organization innovation in order to boost their performance. Future researchers are encouraged to test the model in other environmental settings. Implications for practice were discussed.     

Some new construction of circular weakly balanced repeated measurements designs in periods of two different sizes

Abstract

Balanced repeated measurements designs (RMDs) balance out the residual effects. Williams Latin square designs work as minimal combinatorial balanced as well as variance balanced for RMDs for p (period sizes) = v (number of treatments). If minimal balanced RMDs cannot be constructed for the situations where p must be less than v then weakly balanced RMDs should be preferred. In this article, some generators are developed to generate circular weakly balanced RMDs in periods of two different sizes. To obtain the proposed designs, some construction procedures are also described for some of the cases where we could not develop generators.     

RigiScan data under long-term testosterone therapy: improving long-term blood circulation of penile arteries,penile length and girth,erectile function,and nocturnal penile tumescence and duration

Background: Late-onset hypogonadism (LOH) presents with low serum testosterone (TT) levels and sexual and nonsexual symptoms. Erectile dysfunction affects a man’s self-esteem and as a result partner relationship and quality of life.

Objectives: To investigate the andrological clinical profile outcomes of testosterone therapy (TTh) in men (n?=?88) with symptomatic LOH complaints and symptoms.

Main outcome measures: Erectile function was assessed using the International Index of Erectile Function-5 questionnaire at baseline and at 6 and 12 months of TTh. In addition, penile length was measured at baseline and 12 months. We also evaluated nocturnal penile tumescence (NPT, using RigiScan) and blood flow of cavernous arteries (penile Doppler ultrasonography) at baseline and 12 months of TT.

Materials and methods: Eighty-eight LOH men (M_age 51.1 years) with erectile dysfunction, all with serum TT?<10.4?nmol/L before TTh. Patients received intramuscular long-acting testosterone undecanoate for 12 months.

Results: Following TTh, in all patients, serum TT levels were restored within 3 months to normal levels. Compared with baseline values, erectile function significantly improved at 6 (mean score increase 1.95) and 12 months (mean score increase 2.16). No significant changes in penile length were observed. NPT significantly improved at 12 months in terms of both the frequency (mean increase 1.27 times) and duration of rigidity (mean increase 5.12?min). As regards the blood flow of the cavernous arteries, we observed a significant improvement (decrease of 1.16?cm/s) and end diastolic velocity of the penile arteries.

Conclusion: TTh in men with LOH resulted in improvement of the erectile function, NPT, and to some extent the blood flow of the cavernous arteries.     

Exploring the co-movements between COVID-19 pandemic and international air traffic: A global perspective based on wavelet analysis

The travel and tourism industry was one of the fastest-growing industries before the onset of the COVID-19 pandemic. However, to avoid COVID-19 spread, the government authorities imposed strict lockdown and international border restrictions except for some emergency international flights that badly hit the travel and tourism industry. The study explores the nexus between international air departures and the COVID-19 pandemic in this strain. We use a novel wavelet coherence approach to dissect the lead and lag relationships between international flight departures and COVID-19 deaths from January 2020 to September 2020 (COVID-19 first wave period). The results reveal that international flights cause the spread of COVID-19 spread during May 2020 to June 2020 worldwide. The overall findings suggest asymmetries between daily international flight departures and COVID-19 deaths globally at different time-frequency periods due to uncertainty surrounding the COVID-19 pandemic. The study will be conducive for the policymakers to control the upsurge of COVID-19 spread worldwide.     

International Academic Mobility in Chinese Academia: Opportunities and Challenges

International academic mobility is an important dimension of the internationalization of higher education institutions, which aims to enact practical changes in economies and societies. Although many studies have investigated the mobility of international students, the mobility of international academics has been less investigated, particularly in the context of mainland China. This qualitative study explores the experience of international academics in Chinese academia. The study is based on semi-structured interviews with twenty-six international academics from different countries, working at different universities in Beijing. Through a four-stage systematic analysis, the study shows that international academics’ engagement with mobility in Chinese academia can be characterized by a combination of gains and losses. This article explores how international academics view Chinese academia as either resourceful or restrictive for their academic career. It then discusses the hidden narratives concerning the challenges that international academics face in relation to mobility.     

An effective approach to linear calibration estimation with its applications

Abstract

The availability of some extra information, along with the actual variable of interest, may be easily accessible in different practical situations. A sensible use of the additional source may help to improve the properties of statistical techniques. In this study, we focus on the estimators for calibration and intend to propose a setup where we reply only on first two moments instead of modeling the whole distributional shape. We have proposed an estimator for linear calibration problems and investigated it under normal and skewed environments. We have partitioned its mean squared error into intrinsic and estimation components. We have observed that the bias and mean squared error of the proposed estimator are function of four dimensionless quantities. It is to be noticed that both the classical and the inverse estimators become the special cases of the proposed estimator. Moreover, the mean squared error of the proposed estimator and the exact mean squared error of the inverse estimator coincide. We have also observed that the proposed estimator performs quite well for skewed errors as well. The real data applications are also included in the study for practical considerations.