120 research outputs found
The Marshall-Olkin Odd Burr III-G Family of Distributions: Theory, Estimation and Applications
We propose a new ‡exible class called the Marshall-Olkin odd Burr III family for generating continuous distributions and derive some of its statistical properties. We provide three special models which accommodate symmetrical, right-skewed and left-skewed shaped densities as well as bathtub, decreasing, increasing, upside-down bathtub and reversed-J shaped hazard rates. The model parameters are estimated by maximum likelihood, least squares and a percentile method. Some Monte Carlo simulations are performed to check the adequacy of these methods. The ‡exibility of a special model is illustrated by means of three applications to real data
A contemplating review on different synthesis methods of 2D-Molybdenum disulfide (MoS2) nanosheets
The current challenges arising from the rapid development in science and technology attracted researchers to focus on the development of new advanced materials like two-dimensional (2D) nanomaterials, which offer exceptional features that can be used to resolve different industrial problems, which include enhancing energy storage and conversion systems, improving electronic and optoelectronic devices, advancing catalysis and sensing applications, enabling flexible and transparent electronics, advancing healthcare technologies, and addressing environmental concerns such as pollution monitoring and remediation. There are many different layered-structure materials on earth. To get the desired form of these materials, various scientific approaches are applied in laboratories and processing industries. As a result, different methods have been developed for the synthesis of 2D materials. Among various 2D materials, molybdenum disulfide (MoS2) is one of the emerging and promising transition metal dichalcogenides (TMDs) materials that has remarkable electrical, magnetic, optical, and mechanical characteristics. Furthermore, MoS2 nanosheets, when incorporated in different materials, produce promising results, such as better catalytic activities, improved hydrogen production, a super-capacitive feature, and enhanced battery performances, etc. Therefore, in this review, we have focused on significant and practical techniques for synthesizing 2D-MoS2 nanosheets developed by different researchers over the years. We comprehensively discuss their applications, characteristics, as well as provide a brief introduction to the physical and chemical properties of 2D MoS2 nanosheets. Furthermore, we address the current challenges associated with the synthesis of these nanosheets. These discussions highlights that the choice of synthesis method mainly relies on factors such as material type, resources, complexity, environmental impact, scalability, cost, and desired properties of 2D MoS2 nanosheets. Additionally, this literature review also outlines future research directions aimed at overcoming these challenges and advancing synthesis processes to enable the economically feasible scaled-up production of 2D MoS2 nanosheets
A world of lies
This article reports two worldwide studies of stereotypes about liars. These studies are carried out in 75 different countries and 43 different languages. In Study 1, participants respond to the open-ended question "How can you tell when people are lying?" In Study 2, participants complete a questionnaire about lying. These two studies reveal a dominant pan-cultural stereotype: that liars avert gaze. The authors identify other common beliefs and offer a social control interpretation
Distribution of gastric carcinoma in an area with a high prevalence of Helicobacter pylori.
BACKGROUND/AIMS:
South Asia is an enigma for gastric cancer (GC) because it is a low risk region with a high prevalence of Helicobacter pylori (H. pylori) infections. We evaluated the trend of GC clinical presentation and risk factors in patients with dyspeptic symptoms. MATERIALS AND METHODS:
The medical records of patients, coded by the international classification of diseases (ICD-10-CM, 2015, Diagnosis Code C16.9) for malignancies of stomach diagnosed by esophagogastroduodenoscopy (EGD) and histopathology, were studied. RESULTS:
394 GC cases with a mean age of 54±15 years, range of 18 to 88, were analyzed. 256 (65%) were male. Distal non-cardiac and cardiac tumors were 302 (77%) and 92 (23%) cases, respectively. The WHO classification of GC defined 222 (56%) cases as intestinal type adenocarcinoma, 68 (17%) cases as signet ring cell carcinoma (SRC), 62 (16%) cases as diffuse type and 42 (11%) cases as B cell non-Hodgkin lymphoma. The co-morbid conditions associated with GC were H. pylori infection (positive in 246 (62%) cases), diabetes mellitus type 2 (in 90 (23%) cases), and cigarette smoking (in 94 (24%) cases). Of the male patients, 88 (34%) (p\u3c0.001) were smokers. Body mass index was abnormal in all age groups and in both sexes. Cardiac regions for GC were more common in the 46- to 60-year old age range and in males. Diffuse GC was seen in all age groups but there were significantly more common in the 18- to 45-year old age range. Gastric non-Hodgkin\u27s lymphoma was seen at an early age of 18-45 years in 14(12%) and a later of 61-88 years in 20 (15%). CONCLUSION:
Intestinal type GC is common at all ages but SRC and diffuse GC are more common in patients less than 50 years old. SRC and diffuse GC were not specific to the elderly in our study population
Present and Future CP Measurements
We review theoretical and experimental results on CP violation summarizing
the discussions in the working group on CP violation at the UK phenomenology
workshop 2000 in Durham.Comment: 104 pages, Latex, to appear in Journal of Physics
The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy
Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations.
Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves.
Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p 90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score.
Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care
Stability and monotonicity of Lotka–Volterra type operators
In the present paper,we investigate stability of trajectories ofLotka–Volterra (LV) type operators defined in finite dimensional simplex.We prove that any LV type
operator is a surjection of the simplex. It is introduced a newclass of LV-type operators, called MLV type ones, and we show that trajectories of the introduced operators converge. Moreover, we show that such kind of operators have totally different behavior than f-monotone LV type operators
Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions
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