Modified median quartile double ranked set sampling for estimation of population mean.

Environmental monitoring and assessment aim to gather data economically, without bias, using efficient and cost-effective sampling methods. One such traditional method is Ranked Set Sampling (RSS), often employed to achieve observational economy. This article introduces an innovative two-stage sampling approach for ranked set sampling (RSS) to get a more precise estimate of the population mean. Modified Median Quartile Double Ranked Set Sampling (MMQDRSS) highlights the ranked base technique's potential as a cost-effective sampling method. To evaluate the performance of the proposed estimator by using real-life data and conducting a simulation study to compare the relative efficiency of the proposed estimator with some existing methods.

Integrating endogeneity in survey sampling using instrumental-variable calibration estimator.

The endogeneity problem arises when the auxiliary variables correlate to the error terms. In such cases, appropriate instrumental variables ensure efficient estimation. Calibration has recognized itself as an important methodological tool at a large scale to estimate the population total in survey sampling. Which does not offer efficient estimation in the presence of endogeneity. When endogeneity is present in the auxiliary variables, the calibration using endogenous auxiliary variables may produce biasedness and increase variance due to inappropriate model assumptions. In this article, we propose instrumental-variable calibrated estimators by using the classical instrumental-variables approach for the case of exact identification that are more efficient than conventional calibration estimators when some auxiliary variables are endogenous. The necessary properties of the proposed estimators are presented. Our study is backed by both the simulation study and a real data example to check the performance of the proposed estimators.

Machine learning methods for predicting major types of rheumatic heart diseases in children of Southern Punjab, Pakistan.

Objective: Rheumatic heart disease (RHD) is a major health problem in the world, particularly in developing countries. This study aimed to predict mitral regurgitation (MR) and mitral stenosis (MS) RHD among children with RHD. Methodology: Data was collected from the Pediatric Cardiology Department at Chaudhry Pervaiz Elahi Institute of Cardiology Multan, Pakistan from March to October 2019. A sample of 561 children aged 4-14 years, who were diagnosed with RHD of either MR or MS, were recruited from the hospital's outpatient department. The presence of multivariate outliers was detected, and different machine learning methods, including subset logistic regression, subset logistic regression after deletion, stepwise winsorized logistic regression, robust logistic regression, subset deep neural network, and random forest models were compared using the area under receiver operating characteristics (ROC) curve, sensitivity, and specificity. Parsimony was also considered in model selection. Results: Out of 561 patients in this study, 75.94% had RHD MR and 24.06% had RHD MS. The average age of study participants was 9.19 ± 2.45 years and of them 55.43% were male. Among the male participants, 58.6 and 45.2% had MR and MS, respectively; and among female participants, those were 70.4 and 29.6%, respectively. Subset logistic regression after deletion appeared as competitive with a discrimination power of 90.1% [95% CI 0.818-0.983]. The sensitivity and specificity of this model were 85.1 and 70.6%. Conclusion: The best predictive model was subset logistic regression after deletion. The predicted method will be used in the decision-making process, which helps early diagnosis of the disease and leads to prevention. The study findings provide the proper guideline for earlier diagnosis of the RHD MR and MS cases among children with RHD in Pakistan.

Nutritional status and growth centiles using anthropometric measures of school-aged children and adolescents from Multan district.

BACKGROUND: Nutritional status among children and adolescents is assessed using growth rates. The aim of this study was to assess age- and gender-specific height, weight, and body mass index (BMI) centiles among children and adolescents relative to World Health Organization (WHO) references. METHODS: A sample of 1040 school-aged children and adolescents aged 3-18 years from Multan District in Pakistan were selected for the study between January and March 2020. Multistage stratified random sampling was used for sample selection. Centile curves of height, weight, and BMI for age and gender were obtained using the lambda-mu-sigma (LMS) method, and results were compared with WHO 2007 references. RESULTS: For boys and girls, the average height was 137.37 ± 8.24 and 135.62 ± 9.64 cm, average weight was 36.32 ± 6.84 and 35.21 ± 7.27 kg, and average BMI was 18.44 ± 2.67 and 18.36 ± 2.91, respectively. The height centiles of boys were higher than the WHO reference, and during the prepubertal period (age 8 years or older) the centiles were lower than the WHO reference. The height centiles of girls were higher than the WHO reference, and during the pubertal period (age 10 years or older) the centiles were lower than the WHO reference. The gender-wise BMI centiles were higher compared to the WHO reference. CONCLUSION: The prevalence of thinness, overweight, and obesity in boys and girls was significantly higher than the WHO reference. The results of this study on centiles are up-to-date and will be used as a standard for comparison.

Insect pollinator diversity in four forested ecosystems of southern Punjab, Pakistan.

This study investigated pollinator assemblage diversity and richness in four forested ecosystems of southern Punjab, Pakistan, with different landscape types. Pirowal is situated in the plains of irrigated Punjab, Lal Suhanra is part of a sandy desert ecosystem, Ghazi Ghat is part of the Indus River delta, and Fort Munro is located in dry hilly mountains. A yearlong survey of pollinator populations was carried out in these four forested ecosystems from January to December of 2010. Fortnightly hand netting was performed for collecting flower-visiting insects whereas, pan traps of three colors (white, blue, and yellow) were deployed for collecting the data. A total of 8,812 individuals from two orders (Lepidoptera and Diptera) were observed, including 22 families and 154 species. Bees were the most abundant, with 4,502 individuals, and the most species-rich taxa, with 70 species in five families, followed by flies having 2,509 individuals and 51species in 10 families. Wasps were the least abundant with 1,801 individuals and 33 species in seven families. The assemblage structure of pollinator communities as visualized through rank abundance curves showed that there were many species with low abundance and only a few species with a much higher abundance. The most abundant species among the bees, in order, were Nomia sp.3, Megachile bicolor, and Colletes sp.3; among flies, Syrphus sp.2, Calliphoridae sp.1, and Empididae sp.4; and among wasps, Tiphiidae sp.1, Myzininae sp.2, and Scelionidae sp.1.

Influence of single-nucleotide polymorphisms in the IFNG towards susceptibility to tuberculosis in a Pakistani population.

Tuberculosis (TB) is a global issue as one-third of the population worldwide is considered to be infected. TB has become a critical public health problem as a result of increasing drug resistance, which poses a challenge to current control strategies. Similar to environmental factors, genetic makeup of the host equally contributes to disease onset. We performed genotypic analysis to examine the relationship between IFNG and TB onset and drug resistance in a Pakistani population comprising 689 subjects. Notable differences were observed in the IFNG polymorphism (+874T/A) between the case and control groups. The frequency of the wild-type genotype (TT) in the controls (43.2%) was significantly higher than in the cases (25.3%) (odds ratio [OR] = 0.77, p < 0.0001), while the mutant genotype frequency (AA) (38.57%) in the cases was significantly higher than in the controls (22.6%) (OR = 1.46, p < 0.0001). The heterozygous genotype frequency (TA) did not significantly differ between the control and case groups. Compared with the controls, the variant allele (A) was approximately twice as frequent in the cases. Females and older people have a higher chance of disease development. Finally, the IFNG (+874T/A) polymorphism was not associated with drug sensitivity or resistance. However, a genotypic polymorphism of IFNG (+874T/A) was significantly associated with susceptibility to TB, and the T allele conferred protection against TB. Additional studies involving larger cohorts are needed to further explore this relationship between genetics and disease vulnerability.