How to test normality distribution for a variable: a real example and a simulation study

Many commonly used statistical methods require that the population distribution be nearly normal. Unfortunately, in some papers the one-sample Kolmogorov-Smirnov test has been used for testing normality while the assumptions of applying this test are not satisfied. To conduct this test, it is assumed that the population distribution is fully specified. In practical situation where the mean and SD of population distribution is not specified in advance, one can use a modification of the K-S test for checking the normality assumption which is called, Lilliefors test. In this paper, we explain the method of computing this test with some common statistical softwares such as SPSS, S-PLUS, R and StatXact and utilize a dermatology dataset from Skin Research Center of Shohada-e-Tajrish hospital to illustrate how the use of the one-sample K-S (with the mean and SD estimated from the sample) instead of its modification can be misleading in practice. We also use Monte Carlo simulation to compare the approximate power of the one-sample K-S test (with the estimated population mean and SD) with Lilliefors test in some common specified continuous distributions. The result indicates that one should not use the one-sample K-S test for assessing the normality assumption in practical situation.

Signaling on the Continuous Spectrum of Nonlinear Optical Fiber

This paper studies different signaling techniques on the continuous spectrum (CS) of nonlinear optical fiber defined by nonlinear Fourier transform. Three different signaling techniques are proposed and analyzed based on the statistics of the noise added to CS after propagation along the nonlinear optical fiber. The proposed methods are compared in terms of error performance, distance reach, and complexity. Furthermore, the effect of chromatic dispersion on the data rate and noise in nonlinear spectral domain is investigated. It is demonstrated that, for a given sequence of CS symbols, an optimal bandwidth (or symbol rate) can be determined so that the temporal duration of the propagated signal at the end of the fiber is minimized. In effect, the required guard interval between the subsequently transmitted data packets in time is minimized and the effective data rate is significantly enhanced. Moreover, by selecting the proper signaling method and design criteria a reach distance of 7100 km is reported by only singling on the CS at a rate of 9.6 Gbps

Gastrointestinal bleeding in a newborn infant with congenital factor X deficiency and COVID-19—A common clinical feature between a rare disorder and a new, common infection

Dear Editors, Congenital factor X (FX) deficiency is an extremely rare, bleeding disorder with an estimated incidence of one per 1 million. Patients with severe FX deficiency (FX:C < 1%) demonstrate a wide spectrum of serious clinical presentations, including hemarthrosis, hematoma, gastrointestinal (GI) bleeding, intracranial hemorrhage (ICH), and umbilical cord bleeding.1 In fact, severe FX deficiency, with a high rate of life‐threatening bleeding, is the second‐most severe, rare coagulation factor deficiency (RCFD) after FXIII deficiency.1, 2 Although homozygotes are at risk of severe bleeding, heterozygotes usually are asymptomatic, but postsurgical bleeding or bleeding after childbirth may occur.1, 2 Other risk factors can increase the risk of bleeding in FX deficiency, and coronavirus disease 2019 (COVID‐19), a new medical challenge, could affect the patient's bleeding or thrombotic tendency.3 COVID‐19, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) presents an enormous challenge for everyone, especially for those with underlying risk factors such as cardiovascular disease, diabetes, obesity, and renal failure. Age and male sex are other risk factors.4 Limited data are available regarding the effect of COVID‐19 on patients with congenital bleeding disorders (CBDs), particularly RCFDs.5 It has been shown that hypercoagulability‐related adverse consequences are less common among patients with CBDs, at least in those with moderate‐to‐severe deficiency, but further studies, including our ongoing work on a large number of patients, are required.5 Although there are several reports of newborns among infected pregnant mothers, this is the first report of such a case in an RCFD. This case report may help medical professionals to better manage similar cases. A 19‐year‐old pregnant woman was infected with SARS‐CoV‐2 early in the 9th month of pregnancy. Reverse transcriptase‐polymerase chain reaction (RT‐PCR) confirmed the infection. The patient had been in close contact with family members with confirmed COVID‐19. The patient had cough and fever. Due to the mild presentation, she was given Azithromycin and advised to isolate herself at home. The symptoms resolved within 14 days. At end of her 9th month, three days prior to the planned cesarean section, she was rechecked for SARS‐CoV‐2 infection; her RT‐PCR was negative. She successfully underwent cesarean section without complications and delivered a healthy full‐term baby. Therefore, mother and newborn discharged the following morning. In the evening, the baby experienced bloody vomiting and was hospitalized for further assessment, which showed GI bleeding. At admission, laboratory tests showed a positive C‐reactive protein (CRP) (qualitative), a low hemoglobin level, and prolonged prothrombin time (PT), and activated partial thromboplastin time (APTT) (Table 1). He was hospitalized in the neonate intensive care unit (NICU) for 10 days. Due to the risk of SARS‐CoV‐2 infection, on the third day after admission he was tested by RT‐PCR, which was positive. The neonate received 30 mL frozen plasma (FFP) six times over 10 days, which resolved the GI bleeding. Tranexamic acid (TXA) was administered at a dose of 10 mg/kg every 8 hours. Due to lack of COVID‐19 symptoms, he did not receive any special treatment for the disorder. After 10‐day hospitalization in the NICU, the neonate was sent to an isolation room for 5 days, during which his condition stabilized, after which he was discharged in stable condition. He has had no complications during the past two months after discharge. Since the child's father and two other first‐degree family members have severe FX deficiency, and the parents of the baby are closely related, the mother and the baby were checked for FX deficiency. Routine coagulation tests, and FX:C assay performed by STA Compact automatic coagulometer (Stago, Paris, France), revealed a severe deficiency in the baby, and a mild deficiency, compatible with heterozygote FX deficiency, in the mother (Table 1). Table 1. Laboratory characteristics of mother and baby with factor X deficiency and COVID‐19 Test Proband (2nd day after birth) Proband (7th day after birth) Proband (2 months after hospital discharge) Mother (about 3 1/2 months after SARS‐CoV‐2 infection) WBC × 109/L 14.2 (8‐24)b 9.43 (5‐21) 10.79 (6‐18) 8.7 (3.6‐10.6) RBC × 109/L 2.5 (4.36‐5.96) 2.78 (4.2‐5.8) 3.50 (3.4‐5) 4.41 (3.8‐5.2) Hb (g/dL) 8.2 (16.4‐20.8) 9.2 (15.2‐20.4) 10.2 (10.6‐16.4) 13.6 (12‐15) HCT (%) 24.6 (48‐68) 27 (50‐64) 29.2 (32‐50) 41.4 (35‐49) Lymphocyte × 109/L 6.4 (1.3‐11) 4.3 (1.2‐11.3) 8.21 (2.5‐13) 2.22 (1‐3.2) Neutrophil × 109/L 4.9 (2.6‐17) 2.9 (1.5‐12.6) 1.85 (1.2‐8.1) 5.75 (1.7‐7.5) Platelet × 109/L 370 (150‐450) 331 (150‐450) 334 (150‐450) 276 (150‐450) PT (sec) >60 (PTC: 12.6) 90 (PTC: 12.6) >60 (PTC: 10) 13 (PTC: 10) APTT (sec) >120 (APTTC: 31) 100 (APTTC: 30) >120 (APTTC: 32) 37 (APTTC: 32) CRP (Quantitative) Trace Negative NC NC FX:C level NC NC <1% (50%‐150%) 40% (50%‐150%) Abbreviations: APTT, activated partial thromboplastin time; APTTC, APTT control; CRP, C‐reactive protein; Hb, hemoglobin; HCT, hematocrit; NC, Not checked; PT, prothrombin time; PTC, PT control; RBC, red blood cell; WBC, white blood cell. a Hematological test normal ranges are extracted from Rodak's Hematology: Clinical Principles and Applications, 5th Ed (2016). b Normal values are placed in parentheses. COVID‐19 is an emerging medical challenge that can present more difficulties for those with special conditions, such as pregnant women and newborns. Due to alterations in cellular immunity, pregnant women are more prone to infection by intracellular pathogens like viruses.6 The fetus is also highly susceptible to infection due to immaturity of the immune system.7 Furthermore, the mother's (heterozygote) congenital coagulopathy and that of her newborn (homozygote) were additional potential risk factors, because a disrupted coagulation system is a prominent feature of SARS‐CoV‐2 infection.8 To date, FX deficiency in a newborn has not been cited anywhere as a special condition requiring close attention in the case of SARS‐CoV‐2 infection. According to the few reports to date, SARS‐CoV‐2 infection is a risk factor for severe maternal morbidity. It is worth noting that most of those mothers were discharged without complications.9 From a clinical aspect, fever was the most common symptom (68%) at the time of admission.9 This was also observed in the affected woman of this study. SARS‐CoV‐2 infection can even affect the type of delivery. A systematic review of these women showed that about 92% of deliveries were by cesarean section, less than 10% being the usual vaginal delivery (7 of 85). Fetal distress was mentioned as the most common indication for cesarean section. Our patient underwent a planned cesarean section, due to her previous history. The delivery itself was uneventful, and a healthy baby was delivered, while among other reported cases, a number of complications have been noted.9 As with most other reports, the infant did not have any symptoms at the time of delivery and was discharged the day after birth.9 In a case series of 10 patients, various first clinical presentations were observed, including shortness of breath (n = 6), fever (n = 2), vomiting (n = 1), and rapid heart rate (n = 1).10 In the case at hand, bloody vomiting was the first clinical presentation. In the same case series, one died due to refractory shock, multiple organ failure (MOF), and disseminated intravascular coagulation (DIC). Another patient with severe presentation was managed by intravenous infusions of gamma globulin, platelets, and plasma, which was suggestive of the effectiveness of gamma globulin in severe cases. The author recommended early use of intravenous gamma globulin for passive immunization.10 GI bleeding in our case was successfully managed by administration of FFP and TXA. In addition to thrombotic complication, bleeding is not infrequent in patients affected by COVID‐19, with GI bleeding seemingly the most common hemorrhagic manifestation among adults. GI bleeding, with a frequency of 40%, was observed among neonates from affected mothers.3 On the other hand, GI bleeding is also a relatively common presentation among severely FX deficient patients.1, 2 In fact, GI bleeding can occur in children with severe FX deficiency within the first months of life. It seems that such patients are prone to experience severe bleeding, such as ICH, later in life, in the absence of an appropriate therapeutic strategy, most likely preventative regular secondary prophylaxis.1, 2 In one study of 102 patients with congenital FX deficiency, GI bleeding has been reported in 12% of symptomatic cases.1 In this case, with GI bleeding being a common presentation of SARS‐CoV‐2 infection and congenital FX deficiency, it cannot definitively be attributed to one or the other. Close monitoring of such cases is necessary to decrease related adverse consequences. Although it seems that COVID‐19 is less severe in adults with CBDs, it is a less‐known issue among children and newborns with CBDs. Further reports and studies could provide clarity. Due to their severe bleeding tendency, close monitoring of patients with severe congenital FX deficiency is mandatory, even without potential SARS‐CoV‐2 infection. And close monitoring of neonates with infected mothers is mandatory to prevent severe consequences. Patients with concomitant infection with SARS‐CoV‐2 require even more rigorous preventative and supportive care. ACKNOWLEDGEMENTS We highly appreciate Daisy Morant's valuable aid in improving the English Language of this manuscript. The study was supported and approved by Shahid Beheshti University of Medical Sciences. CONFLICT OF INTEREST The authors have no competing interests. AUTHOR CONTRIBUTIONS A. Dorgalaleh designed the work, performed laboratory analysis, and wrote the manuscript. F Ghazizadeh, M. Baghaipour, A. Dabbagh, Gh. Bahoush, and N Baghaipour performed clinical studies. Sh. Tabibian, M. Jazebi, N. Baghaipour, M. Bahraini, A. Fazeli, and F. Yousefi performed laboratory analysis. All the authors approved the submission

Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017

Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe

Estimating global injuries morbidity and mortality : methods and data used in the Global Burden of Disease 2017 study

Background While there is a long history of measuring death and disability from injuries, modern research methods must account for the wide spectrum of disability that can occur in an injury, and must provide estimates with sufficient demographic, geographical and temporal detail to be useful for policy makers. The Global Burden of Disease (GBD) 2017 study used methods to provide highly detailed estimates of global injury burden that meet these criteria. Methods In this study, we report and discuss the methods used in GBD 2017 for injury morbidity and mortality burden estimation. In summary, these methods included estimating cause-specific mortality for every cause of injury, and then estimating incidence for every cause of injury. Non-fatal disability for each cause is then calculated based on the probabilities of suffering from different types of bodily injury experienced. Results GBD 2017 produced morbidity and mortality estimates for 38 causes of injury. Estimates were produced in terms of incidence, prevalence, years lived with disability, cause-specific mortality, years of life lost and disability-adjusted life-years for a 28-year period for 22 age groups, 195 countries and both sexes. Conclusions GBD 2017 demonstrated a complex and sophisticated series of analytical steps using the largest known database of morbidity and mortality data on injuries. GBD 2017 results should be used to help inform injury prevention policy making and resource allocation. We also identify important avenues for improving injury burden estimation in the future.Peer reviewe

Global, regional, and national cancer incidence, mortality, years of life lost, years lived with disability, and disability-Adjusted life-years for 29 cancer groups, 1990 to 2017 : A systematic analysis for the global burden of disease study

Importance: Cancer and other noncommunicable diseases (NCDs) are now widely recognized as a threat to global development. The latest United Nations high-level meeting on NCDs reaffirmed this observation and also highlighted the slow progress in meeting the 2011 Political Declaration on the Prevention and Control of Noncommunicable Diseases and the third Sustainable Development Goal. Lack of situational analyses, priority setting, and budgeting have been identified as major obstacles in achieving these goals. All of these have in common that they require information on the local cancer epidemiology. The Global Burden of Disease (GBD) study is uniquely poised to provide these crucial data. Objective: To describe cancer burden for 29 cancer groups in 195 countries from 1990 through 2017 to provide data needed for cancer control planning. Evidence Review: We used the GBD study estimation methods to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-Adjusted life-years (DALYs). Results are presented at the national level as well as by Socio-demographic Index (SDI), a composite indicator of income, educational attainment, and total fertility rate. We also analyzed the influence of the epidemiological vs the demographic transition on cancer incidence. Findings: In 2017, there were 24.5 million incident cancer cases worldwide (16.8 million without nonmelanoma skin cancer [NMSC]) and 9.6 million cancer deaths. The majority of cancer DALYs came from years of life lost (97%), and only 3% came from years lived with disability. The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes. In 2017, the most common incident cancers in men were NMSC (4.3 million incident cases); tracheal, bronchus, and lung (TBL) cancer (1.5 million incident cases); and prostate cancer (1.3 million incident cases). The most common causes of cancer deaths and DALYs for men were TBL cancer (1.3 million deaths and 28.4 million DALYs), liver cancer (572000 deaths and 15.2 million DALYs), and stomach cancer (542000 deaths and 12.2 million DALYs). For women in 2017, the most common incident cancers were NMSC (3.3 million incident cases), breast cancer (1.9 million incident cases), and colorectal cancer (819000 incident cases). The leading causes of cancer deaths and DALYs for women were breast cancer (601000 deaths and 17.4 million DALYs), TBL cancer (596000 deaths and 12.6 million DALYs), and colorectal cancer (414000 deaths and 8.3 million DALYs). Conclusions and Relevance: The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care and screening. The GBD study can be used by policy makers and other stakeholders to develop and improve national and local cancer control in order to achieve the global targets and improve equity in cancer care. © 2019 American Medical Association. All rights reserved.Peer reviewe

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

COVID-19 cases correlate with greater acceptance coping in flexible cultures: A cross-cultural study in 26 countries

The current study examines whether the prevalence of COVID-19 cases and cultural flexibility correlate to one's use of acceptance coping across 26 cultures. We analyzed data from 7476 participants worldwide at the start of the first outbreak from March 2020 to June 2020. Results showed that cultural flexibility moderated the relationship between COVID-19 cases and individuals' acceptance coping strategies. Specifically, for cultures with high flexibility, COVID-19 cases correlated with more acceptance coping; for cultures with low flexibility, COVID-19 cases correlated with less acceptance coping. This result demonstrates how participants from flexible cultures can coexist with the realistic challenges and suffering faced during this pandemic

Growth and characterization of PbO Nanorods grown using facile oxidation of lead sheet

PbO nanorods were synthesized by oxidation of lead sheets under an oxygen ambiance with different temperatures at 330, 400, 450 and 550ºC in a tube furnace. Scanning electron microscope (SEM) results showed that the nanorods started growing on the sheet that was placed at 330ºC. On the other hand, by increasing of the temperature to 550°C more nanorods appeared on the Pb sheet, which were lied on the lead sheet. X-ray diffraction pattern (XRD) indicated that the nanorods had α-PbO structures. However, a few β-PbO phases also appeared for the nanorods. Raman measurements confirmed the XRD results and indicated two Raman active modes that belonged to α-PbO phase for the nanorods. In addition, the Raman spectrum of the nanorods showed a weak peak of the β-PbO structure. The optical properties of the products were characterized using a room temperature photoluminescence (PL) technique. The PL result indicated a band gap for the PbO nanorods in the visible region

Active human gesture capture for diagnosing and treating movement disorders

Movement disorders prevent many people fromenjoying their daily lives. As with other diseases, diagnosisand analysis are key issues in treating such disorders.Computer vision-based motion capture systems are helpfultools for accomplishing this task. However Classical motiontracking systems suffer from several limitations. First theyare not cost effective. Second these systems cannot detectminute motions accurately. Finally they are spatially limitedto the lab environment where the system is installed. In thisproject, we propose an innovative solution to solve the abovementionedissues. Mounting the camera on human body, webuild a convenient, low cost motion capture system that canbe used by the patient in daily-life activities. We refer tothis system as active motion capture, which is not confinedto the lab environment. Real-time experiments in our labrevealed the robustness and accuracy of the system