Tag: statistics

PLoS One. 2021 Jul 26;16(7):e0254999. doi: 10.1371/journal.pone.0254999. eCollection 2021.

ABSTRACT

Over the past few months, the spread of the current COVID-19 epidemic has caused tremendous damage worldwide, and unstable many countries economically. Detailed scientific analysis of this event is currently underway to come. However, it is very important to have the right facts and figures to take all possible actions that are needed to avoid COVID-19. In the practice and application of big data sciences, it is always of interest to provide the best description of the data under consideration. The recent studies have shown the potential of statistical distributions in modeling data in applied sciences, especially in medical science. In this article, we continue to carry this area of research, and introduce a new statistical model called the arcsine modified Weibull distribution. The proposed model is introduced using the modified Weibull distribution with the arcsine-X approach which is based on the trigonometric strategy. The maximum likelihood estimators of the parameters of the new model are obtained and the performance these estimators are assessed by conducting a Monte Carlo simulation study. Finally, the effectiveness and utility of the arcsine modified Weibull distribution are demonstrated by modeling COVID-19 patients data. The data set represents the survival times of fifty-three patients taken from a hospital in China. The practical application shows that the proposed model out-classed the competitive models and can be chosen as a good candidate distribution for modeling COVID-19, and other related data sets.

PMID:34310646 | DOI:10.1371/journal.pone.0254999

PLoS One. 2021 Jul 26;16(7):e0255041. doi: 10.1371/journal.pone.0255041. eCollection 2021.

ABSTRACT

The COVID-19 pandemic has changed the functioning of universities worldwide. In Poland, the transfer to online teaching was announced without prior warning, which radically changed students’ daily functioning. This situation clearly showed the students’ helplessness and difficulties with coping with this new, stressful situation, highlighted in many previous studies. A sudden and far-reaching change in daily functioning caused anxiety, depression, and stress in this group. Thus, from a pedagogical and psychological point of view, it is pertinent to examine the students’ strategies of coping with stress caused by the COVID-19 pandemic. To this end, in 2020, a sample of Polish students was anonymously measured using the Mini-COPE questionnaire. Data was gathered from 577 students from 17 universities. The statistical analysis showed that during the coronavirus pandemic, Polish students most often used the coping strategies of: acceptance, planning, and seeking emotional support. Such factors as age, gender, and place of residence influenced the choice of specific strategies of coping with stress during the COVID-19 pandemic. The results also showed that the youngest students had the lowest coping skills. The results allow for concluding that the students’ maladaptive strategies of coping with stress, especially during the pandemic, may result in long-term consequences for their psychophysiological health and academic achievements. Thus, based on the current results and on the participatory model of intervention, a support program for students is proposed which would involve psychological, organizational, and instrumental support.

PMID:34310649 | DOI:10.1371/journal.pone.0255041

Panminerva Med. 2021 Jul 26. doi: 10.23736/S0031-0808.21.04500-6. Online ahead of print.

ABSTRACT

BACKGROUND: Helicobacter pylori (H. pylori), main agents of several gastroduodenal diseases, represents a therapeutic challenge. Since the influence of age on the success of bacterial treatment remains uncertain, in this case-control study we assessed the efficacy of a standard H. pylori eradication therapy among elderly patients.

METHODS: In this retrospective study, a total of 361 naïve patients (194 males, mean age 79.8± 3.4 years) aged more than 65 years and treated with a triple therapy regimen comprising a standard dose of omeprazole twice daily, amoxicillin 1g twice daily and clarithromycin 500 mg twice daily, for 7, 10 or 14 days, were included. They were compared with naïve patients, younger than 65 years (mean age 43± 2.7 years). Since in the year 2017, we began to use the three-in-one single capsule bismuth-containing quadruple therapy, the search was ended at 31 December 2016.

RESULTS: Overall, H. pylori eradication rate in the intention-to-treat (ITT) analysis, was 70.9% (256/361) among elderly patients versus 70.9% (256/361) among young patients. Dividing by treatment duration, among elderly patients, eradication was obtained in 78.1% (50/64), 69.1% (139/201) and 69.7% (67/96) elderly patients within 7-day, 10-day and 14-day regimens, respectively, without statistical difference. Out of 361 elderly patients, 11 were excluded from the per protocol (PP) analysis because of discontinuations (7 for adverse events). One subject discontinued treatment among young patients. Also the PP analysis showed no statistical difference, with an eradication rate of 73.1% (256/350) among elderly patients versus 71.1% (256/360) among young patients.

CONCLUSIONS: Elderly does not affect efficacy or safety of a clarithromycin-based triple therapy for H. pylori eradication.

PMID:34309333 | DOI:10.23736/S0031-0808.21.04500-6

Arch Argent Pediatr. 2021 Aug;119(4):259-265. doi: 10.5546/aap.2021.eng.259.

ABSTRACT

INTRODUCTION: Patient handoff is an interactive process including data communication and responsible transfer in order to safely maintain the continuity of care. Failure in this process may result in inadequate care and favor the occurrence of errors.

OBJECTIVE: To implement a standardized instrument for patient handoff from the intensive care unit (ICU) to the intermediate-medium care unit (IMCU), and compare communication between health care providers before and after the intervention.

POPULATION AND METHODS: Before-and-after study conducted at Hospital de Pediatría “Prof. Dr. Juan P. Garrahan.” The intervention consisted in a written handoff form. The pre-intervention sample included patients transferred from ICUs to IMCUs between October 1st and October 31st, 2015. The post-intervention sample included patients transferred between March 1st and March 31st, 2016. A total of 4 IMCUs and 3 ICUs participated in the study. The main study variable was the written part of the handoff; in particular, whether it was timely and complete.

RESULTS: A total of 50 handoffs were analyzed for each stage. With the written handoff, there was an increase in the communication of clinical data in 88 % of variables (oral communication between physicians, treating physician, therapeutic adequacy, diagnosis, course, etc.); the difference was statistically significant.

CONCLUSION: After implementing the tool, there was an improvement in the transfer of patient clinical data relevant to the safe continuity of care.

PMID:34309302 | DOI:10.5546/aap.2021.eng.259

Arch Argent Pediatr. 2021 Aug;119(4):273-278. doi: 10.5546/aap.2021.eng.273.

ABSTRACT

The incidence of pediatric cardiac arrest is unknown; its main etiologies are congenital heart diseases, cardiomyopathies, and ventricular arrhythmias. An electrocardiogram (ECG) is a diagnostic method that may allow to detect them in an early manner and reduce morbidity and mortality. The objective of this study was to describe pediatric residents’ skills to determine if an ECG was normal or abnormal and make an accurate electrocardiographic diagnosis before and after an educational intervention. First-year pediatric residents participated in this study. An assessment including 12 ECG tracings was done before and after an educational module, and scores were compared using the t-test for paired data. No differences were observed between both assessments regarding the interpretation of ECG as normal or abnormal (p: 0.42). However, a statistically significant difference was observed in definitive diagnoses (p < 0.002). Definitive electrocardiographic diagnoses improved after the implementation of an educational module.

PMID:34309305 | DOI:10.5546/aap.2021.eng.273

Huan Jing Ke Xue. 2021 Aug 8;42(8):3773-3784. doi: 10.13227/j.hjkx.202011120.

ABSTRACT

Currently, the aquatic environment of the Tuojiang River basin in Sichuan Province is severely polluted by non-point sources of total nitrogen (TN). This study adopts the pollution discharge coefficient method to estimate the TN pollution load of non-point sources in this watershed during 2007-2017. The temporal and spatial distribution and transfer trends of the TN pollution load in the Tuojiang River basin were examined, based on center-of-gravity statistical and spatial analysis technology. This study aimed to provide an accurate theoretical basis for the prevention and early identification of non-point source pollution in the Tuojiang River basin. The results indicate that livestock breeding was the main non-point source of TN pollution and contributed more than 45% to the TN pollution load during 2007-2017. The contribution rate of rural life and domestic waste decreased continually during the study period, whereas that of farmland solid waste and farmland runoff exhibited an increasing trend. The total pollution load of TN exhibited a decreasing trend during 2007-2017. The maximum and minimum TN pollution loads occurred in 2010 and 2017 with values of 5.7×10⁴ t and 4.69×10⁴ t, respectively. Spatial heterogeneity of the pollution load, together with the uneven distribution of rainfall runoff, caused a shift from northwest to southeast in the pollution-load centers of gravity for livestock and poultry breeding, farmland solid waste, and farmland runoff. Southeast of the watershed is the key area for prevention and control of these pollution sources. A shift in the centers of gravity for rural living and household waste pollution, from southeast to northwest, was attributed to agricultural populations transforming to urban populations in the southeastern counties. The maximum transfer range was 66.35 km², and this minimum boundary circle is the key identification area of pollution source pollution load change. Northwest of Tuojiang River basin is the key area in which TN pollution from rural living and rural household waste can be prevented. This research expands the methods for exploring the temporal and spatial evolution of pollution load in the Tuojiang River basin, which is of great significance for improving the aquatic environment and promoting sustainable development of the basin economy.

PMID:34309263 | DOI:10.13227/j.hjkx.202011120

Huan Jing Ke Xue. 2021 Aug 8;42(8):3904-3912. doi: 10.13227/j.hjkx.202012215.

ABSTRACT

To evaluate the pollution by polycyclic aromatic hydrocarbons (PAHs) in the surface soil of the core urban area of Lanzhou, 62 topsoil samples were collected from the area. The soil samples were analyzed for the content of 16 priority PAHs, using gas chromatography-mass spectrometry. Descriptive statistical methods were used to characterize contamination by PAHs. An absolute principal component analysis-multiple linear regression (APCS-MLR) model was applied to determine the sources of PAHs in the soil samples, and the accuracy of the model results was verified. Finally, the main influence regions of each source were determined with a geo-statistical method. The results showed that the contents of Σ₁₆ PAHs in the surface soils of Lanzhou ranged from 1069 to 7377 μg ·kg^-1, with an average of 2423 μg ·kg^-1. High molecular weight PAHs (4-6 rings) were dominant, accounting for 72.81% of the Σ₁₆ PAHs. Verification results of the APCS-MLR model showed that the measured values were in good correspondence with the predicted values, which indicated that the model had good applicability for source apportionment of soil PAHs in the study area. The main sources of PAHs in Lanzhou were traffic emissions (35.42%), petroleum emissions (29.88%), and a mixture of coal and biomass combustion (33.91%). The sources were greatly affected by human activities, and high values were mainly distributed in traffic-intensive and industrial areas. The results indicated that the sources of soil PAHs were complex and influenced by anthropogenic activities in the study area. Stringent control measures should be placed on the sources and areas of influence that contribute to soil PAHs to reduce the emissions and the level of soil pollution resulting from PAHs.

PMID:34309277 | DOI:10.13227/j.hjkx.202012215

Arch Argent Pediatr. 2021 Aug;119(4):251-258. doi: 10.5546/aap.2021.eng.251.

ABSTRACT

INTRODUCTION: The Prader orchidometer is the standard method used to measure testicular volume (TV) in children and adolescents.

OBJECTIVE: To assess the concordance in the estimation of TV and puberty onset with the Prader, Chipkevitch, and Sotos orchidometric techniques.

METHODS: Cross-sectional descriptive study conducted among male children and adolescents aged 9-20 years. For each adolescent, TV was measured with the methods by Prader (gold standard), Chipkevitch (graphic model), and Sotos (measurement of testicular width with a plastic ruler and use of a formula equivalent to the ellipsoid equation). Male children and adolescents with urogenital conditions and disorders affecting testicular growth were excluded. Kappa statistics was used to determine concordance among methods for puberty onset, and intraclass correlation coefficient (ICC) and Bland-Altman (B&A) plots for TV.

RESULTS: In total, 377 healthy males were included. Regarding the concordance for TV (mL), the Prader-Chipkevitch comparison obtained an ICC of 0.994 and a p< 0.001; while the Prader- Soto comparison obtained an ICC of 0.312 and a p< 0.001. With the B&A plots, mean differences were close to 0 mL in the Prader-Chipkevitch comparison and close to 8 mL in the Prader- Sotos comparison. Concordance for puberty onset obtained a kappa value of 0.93 and 0.75 in the Prader-Chipkevitch and Prader-Sotos comparisons, respectively.

CONCLUSION: The Prader and Chipkevitch orchidometers show an excellent concordance in estimating TV and puberty onset; therefore, both methods could be used interchangeably in the daily care of male adolescents. The Sotos method showed a high concordance in estimating pubertal onset, but low in measuring TV.

PMID:34309301 | DOI:10.5546/aap.2021.eng.251

J Diabetes Investig. 2021 Jul 26. doi: 10.1111/jdi.13635. Online ahead of print.

ABSTRACT

AIMS/INTRODUCTION: Cardiovascular autonomic neuropathy (CAN) is a predictor of cardiovascular disease and mortality. Cardiovascular reflex tests (CARTs) are the gold-standard for diagnosis of CAN, but may not be feasible in large research cohorts or in clinical care. We investigated whether measures of heart rate variability (HRV) obtained from standard ECG recordings provide a reliable measure of CAN.

MATERIALS AND METHODS: Standardized CARTs (R-R response to paced breathing, Valsalva, postural changes) and digitized 12-lead resting ECGs were obtained concomitantly in DCCT/EDIC participants (n=311). Standard deviation of normally conducted R-R intervals (SDNN), and the root mean square of successive differences between normal-to-normal R-R intervals (rMSSD) were measured from ECG. Sensitivity, specificity, probability of correct classification, and Kappa statistics evaluated the agreement between ECG-derived CAN and CARTs-defined CAN.

RESULTS: Participants with CARTs-defined CAN had significantly lower SDNN and rMSSD compared to those without CAN (p<0.001). The optimal cut-off points of ECG-derived CAN were <17.13 and <24.94 milliseconds for SDNN and rMSSD, respectively. SDDN plays a dominant role in defining CAN, with an AUC of 0.73, indicating fair test performance. The Kappa statistics (95% confidence interval) for SDNN was 0.41 (0.30,0.51) for the optimal cut-off point, showing fair agreement with CARTs-defined CAN. Combining SDNN and rMSSD optimal cut-off points does not provide additional predictive power for CAN.

CONCLUSIONS: These analyses are the first to show the agreement between indices of HRV derived from ECGs and the gold standard CARTs, thus supporting potential use as a measure of CAN in clinical research and clinical care.

PMID:34309223 | DOI:10.1111/jdi.13635

Huan Jing Ke Xue. 2021 Aug 8;42(8):3695-3708. doi: 10.13227/j.hjkx.202012229.

ABSTRACT

To explore the isotopic distribution and differentiation of water along the hydraulic flow gradients and plant-bed/ditch systems in constructed root-channel wetlands, surface and subsurface water samples were collected from four ecological wetlands, namely Shijiuyang and Guanjinggang in Jiaxing, as well as Changshuitang and Taishangang in Haining. All samples were collected along water flow pathways during the wet and rainy summer season in August 2019, except for those from Taishangang, which were collected within the plant-bed/ditch system during the dry and cold winter season in January 2020. The abundance of deuterium (δD) and δ¹⁸ O was determined in each functional area of the wetlands to assess the influence of wetlands on water differentiation. Stable isotope technology and mathematical statistics were used to analyze the distribution of δD and δ¹⁸ O in constructed root-channel wetlands and to reveal the influence of plant-bed/ditch systems on stable isotopes of water. A variety of data mining methods were used to examine the differentiation of stable isotopes of water, at various dimensions and scales, including nonparametric Kendall’s tau-b correlation, stepwise regression, gray relational analysis, and machine learning (random forest) combined with scatter diagrams and model hypothesis diagnosis analysis. The main results were as follows:① The spatiotemporal variations in water isotopes of stream networks were largely affected by different water supply and evaporation enrichment effects. The slope and intercept of the wetland water line in Jiaxing were both significantly lower than the regional precipitation line of the adjacent Changshu Station (CHNIP). This showed that the wetlands area had undergone hydrogen and oxygen isotope enrichment. The δD values in Shijiuyang wetland water ranged from -52.2‰ to -49.4‰, and δ¹⁸ O values ranged from -7.6‰ to -6.9‰. In Guanjinggang wetland water samples, δD ranged from -48.1‰ to -45.1‰, and δ¹⁸ O ranged from -6.8‰ to -5.8‰. The δD values in Changshuitang wetland water ranged from -49.8‰ to -48.4‰, and δ¹⁸ O ranged from -7.2‰ to -6.6‰. The δD values in Taishangang wetland water ranged from -55.3‰ to -51.6‰, and δ¹⁸ O ranged from -7.8‰ to -7.2‰. ② Hydrogen and oxygen isotope abundance and composition of water showed complex nonlinear changes in the vertical and horizontal dimensions at different scales. At the regional scale, water level elevation in the vertical dimension had a greater impact on water isotope distribution than the length of the hydraulic flow pathway in the horizontal dimension. Water isotopes tended to be enriched in low-lying areas with low water levels. At the local scale, the influence of hydraulic process often played a greater role in determining water isotope distributions. The spatial variations of water isotopes were comprehensively determined by the evaporation of regional water and meandering hydraulic processes inside the wetland. ③ Compared with other wetland functional areas, the central constructed root-channel area (middle treatment zone) was more enriched in water isotopes. ④ The underground macropore network formed by plants with developed rhizomes or roots (e.g., Phragmites communis Trin. and Typha orientalis Presl), mineral-rich substrate soil, and aquatic plants in the plant bed had a significant influence on the abundance of hydrogen and oxygen isotopes in the plant-bed/ditch system. Therefore, when water passed through the plant-bed/ditch system, the values of δD and δ¹⁸ O in the lower ditch (outlet) were lower than those in the higher ditch (inlet). ⑤ The abrupt change in isotopic contents of the plant-bed/ditch system might indicate an inflection point in water quality purification. ⑥ The deuterium excess (d-excess) in subsurface water of the plant-bed/ditch system was significantly higher than that in ditch water, and the coefficient of variation in subsurface water was considerably greater than that in ditch water. The d-excess in the wetland root-channel ecological purification zone showed significant temporal differences and was negative in the summer and positive in the winter, which reflected the seasonal variation in water vapor sources and the spatial variation in isotope fractionation behavior in wetlands. These results provide some understanding of the distribution of water isotopes in constructed wetlands, which will strengthen their operation and management. This study also provides some ideas regarding new technologies for water quality improvement and shows that water isotope technology may be a reliable method for analyzing wetland hydrology.

PMID:34309256 | DOI:10.13227/j.hjkx.202012229