47 research outputs found
High Capacity Data Embedding using joint Intermediate Significant Bit (ISB) and Least Significant Bit (LSB) Technique
The success of the Internet, coupled with availability of relatively inexpensive digital devices has created an environment in which it has become very easy to obtain, replicate and distribute digital content without any loss in quality. In such a scenario, data hiding has received significant attention from the research community round the globe, as it has been found useful in various areas like copyright protection, copy control, fingerprinting, content authentication and information security. Least Significant Bit based data hiding techniques have been used as effective means to hide the data to be secured, but they are less robust in nature. This paper presents a high capacity data hiding technique in which the data to be secured is embedded in Intermediate Significant Bits in addition to Least Significant Bits of cover image. The data to be embedded is broken down in data blocks of variable length and each block is embedded in the cover media in such a way that highest length data vector is embedded in lower order bit plane and vice-versa. This work shows attractive results with respect to imperceptibility and capacity when compared with a few reported techniques. Key Words: Intermediate Significant Bit, Embedding, Imperceptibility, Least Significant Bit.
On the Realization of Non-Linear Pseudo-Noise Generator for various Signal Processing and Communication Applications
In digital communication systems and digital signal processing, the design of pseudo-noise (PN) sequences having good correlation properties has been one of the most important development steps. Its well-known application areas include spread spectrum communications, Multiuser Communications, Digital Signal Processing for reduction of power spectral density, mitigation of Multiple Access Interference (MAI) and improvement of signal to noise ratio (SNR) respectively. In this paper a performance of non- linear PN code generator for interference rejection improvement of signal to noise ratio in signal processing applications have been studied. The signal of interest can be considered to be a digitally controlled wide band digital chaotic signal, which has been implemented by conventional PN code generators. The proposed technique can be used as an alternative code for improvement in signal to noise ratio, interference rejection, spreading code for various signal processing and communication applications. The proposed scheme has been implemented using matlab as a simulation tool. Power spectral density, auto-correlation and cross-correlation property have been thoroughly studied and has been compared with conventional scheme and are presented in the paper. Keywords: PN Code Generator, Spread Spectrum Modulation, Auto-correlation, Cross-correlation, Power Spectral Density
Data Hiding in Color Images: A High Capacity Data Hiding Technique for Covert Communication
A high capacity data hiding technique using color images as cover medium and referred to as 4R-4G-4B technique has been investigated and presented in this paper. The color image is firstly divided into its constituent bit planes followed by data embedding. To thwart the adversary different embedding algorithms have been used for embedding data in Red, Green and Blue planes. Additional layer of security to the embedded data is added by embedding secret data at the pseudorandom locations determined by Main Address Vector (MAV) and Complementary Address Vector (CAV). The comparison of our method with an existing technique shows that proposed technique is capable of providing better quality stego-images even if the embedded data is slightly more. A 2.7dB increase in PSNR in case of proposed technique substantiates the argument
Compliance of smokeless tobacco supply chain actors and products with tobacco control laws in Bangladesh, India and Pakistan: protocol for a multicentre sequential mixed-methods study
Introduction: South Asia is home to more than 300 million smokeless tobacco (ST) users. Bangladesh, India and Pakistan as signatories to the Framework Convention for Tobacco Control (FCTC) have developed policies aimed at curbing the use of tobacco. The objective of this study is to assess the compliance of ST point-of-sale (POS) vendors and the supply chain with the articles of the FCTC and specifically with national tobacco control laws. We also aim to assess disparities in compliance with tobacco control laws between ST and smoked tobacco products. Methods and analysis: The study will be carried out at two sites each in Bangladesh, India and Pakistan. We will conduct a sequential mixed-methods study with five components: (1) mapping of ST POS, (2) analyses of ST samples packaging, (3) observation, (4) survey interviews of POS and (5) in-depth interviews with wholesale dealers/suppliers/manufacturers of ST. We aim to conduct at least 300 POS survey interviews and observations, and 6-10 in-depth interviews in each of the three countries. Data collection will be done by trained data collectors. The main statistical analysis will report the frequencies and proportions of shops that comply with the FCTC and local tobacco control policies, and provide a 95% CI of these estimates. The qualitative in-depth interview data will be analysed using the framework approach. The findings will be connected, each component informing the focus and/or design of the next component. Ethics and dissemination: Ethical approvals for the study have been received from the Health Sciences Research Governance Committee at the University of York, UK. In-country approvals were taken from the National Bioethics Committee in Pakistan, the Bangladesh Medical Research Council and the Indian Medical Research Council. Our results will be disseminated via scientific conferences, peer-reviewed research publications and press releases
Prevalence and Determinants of Metabolic Syndrome in Qatar: Results from a National Health Survey
OBJECTIVES: To determine optimum measurements for abdominal obesity and to assess the prevalence and determinants of metabolic syndrome in Qatar.
DESIGN: National health survey.
SETTING: Qatar National STEPwise Survey conducted by the Supreme Council of Health during 2012.
PARTICIPANTS: 2496 Qatari citizens aged 18-64 representative of the general population.
PRIMARY AND SECONDARY OUTCOME MEASURES: Measure of obesity (body mass index, waist circumference or waist-to-height ratio) that best identified the presence of at least 2 other factors of metabolic syndrome; cut-off values of waist circumference; frequency of metabolic syndrome.
RESULTS: Waist circumference ≥102 for men and ≥94 cm for women was the best predictor of the presence of other determinants of metabolic syndrome (raised blood pressure, fasting blood glucose, triglycerides and reduced high-density lipoprotein cholesterol). Using these values, we identified 28% of Qataris with metabolic syndrome, which is considerably lower than the estimate of 37% calculated using the International Diabetes Federation (IDF) criteria. Restricting the analysis to participants without known elevated blood pressure, elevated blood sugar or diabetes 16.5% would be classified as having metabolic syndrome. In a multivariable logistic regression analysis, the prevalence of metabolic syndrome increased steadily with age (OR=3.40 (95% CI 2.02 to 5.74), OR=5.66 (3.65 to 8.78), OR=10.2 (5.98 to 17.6) and OR=18.2 (7.01 to 47.5) for those in the age group \u2730-39\u27, \u2740-49\u27, \u2750-59\u27, \u2760-64\u27 vs \u2718-29\u27; p
CONCLUSIONS: Waist circumference was the best measure of obesity to combine with other variables to construct a country-specific definition of metabolic syndrome in Qatar. Approximately 28% of adult Qatari citizens satisfy the criteria for metabolic syndrome, which increased significantly with age. Education and physical activity were inversely associated with this syndrome
Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.
Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability
Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey
Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation