88 research outputs found

    Modeling Cellular Networks in Fading Environments with Dominant Specular Components

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    Stochastic geometry (SG) has been widely accepted as a fundamental tool for modeling and analyzing cellular networks. However, the fading models used with SG analysis are mainly confined to the simplistic Rayleigh fading, which is extended to the Nakagami-m fading in some special cases. However, neither the Rayleigh nor the Nakagami-m accounts for dominant specular components (DSCs) which may appear in realistic fading channels. In this paper, we present a tractable model for cellular networks with generalized two-ray (GTR) fading channel. The GTR fading explicitly accounts for two DSCs in addition to the diffuse components and offers high flexibility to capture diverse fading channels that appear in realistic outdoor/indoor wireless communication scenarios. It also encompasses the famous Rayleigh and Rician fading as special cases. To this end, the prominent effect of DSCs is highlighted in terms of average spectral efficiency.Comment: IEEE ICC1

    Modeling and Analysis of Cellular Networks Using Stochastic Geometry: A Tutorial

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    This paper presents a tutorial on stochastic geometry (SG)-based analysis for cellular networks. This tutorial is distinguished by its depth with respect to wireless communication details and its focus on cellular networks. This paper starts by modeling and analyzing the baseband interference in a baseline single-tier downlink cellular network with single antenna base stations and universal frequency reuse. Then, it characterizes signal-to-interference-plus-noise-ratio and its related performance metrics. In particular, a unified approach to conduct error probability, outage probability, and transmission rate analysis is presented. Although the main focus of this paper is on cellular networks, the presented unified approach applies for other types of wireless networks that impose interference protection around receivers. This paper then extends the unified approach to capture cellular network characteristics (e.g., frequency reuse, multiple antenna, power control, etc.). It also presents numerical examples associated with demonstrations and discussions. To this end, this paper highlights the state-of-the-art research and points out future research directions

    Market Integration Shape Organic Farmers’ Organisation

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    Increasing consumption of organic products in globalised food chains will require the involvement of thousands more smallholder farmers in many regions of the world. A study of Egypt, China and Uganda identified the three key factors of property rights regimes, cultural differences and social organisation as determents of the supply chain organization and farmers’ degree of direct integration in the export markets. Patterns are emerging where smallholder farmers are being socially and economically linked to larger farmers who may do some processing before the raw materials are handed over to the contracting company. Where transactions costs are high, local communities may develop and contract out the land directly to exporting companies who farm using employees. Four organisational patterns are identified which each leads to different types of livelihood benefits for the producers; preliminary results indicate that income and a reliable market access is the dominant benefits

    Thyroid disorders, epidemiology and outcome among patients in South Western region: Southern Saudi Arabia

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    Background: Thyroid gland may have a group of a medical condition that affects its main function. The thyroid gland is located at the front of the neck and produces thyroid hormones. The released hormones go through the blood to many body organs for regulating their function, meaning that it is an endocrine organ. These hormones normally act in the body to regulate energy use, infant development, and childhood development. The study aimed to assess the epidemiology of thyroid disorders among cases in the south-western region, Saudi Arabia, and to assess the reporting quality for these cases data.Methods: A retrospective record based descriptive approach was used through reviewing medical records of all cases that were admitted and diagnosed as thyroid related disorders for different indications in the main hospital (king Khalid Hospital) during the period from January 2018 to January 2020. Data extracted throng pre-structured questionnaire including patient's bio-clinical data, preoperative radiological and laboratory investigations. Also, laryngoscope pre and post operatively was reviewed to record findings.Results: The study included 405 cases with thyroid disorders whose ages ranged from 15 to 71 years old with a mean age of 30.5±10.6 years. Females were 82.7% of the included cases, and 83.8% were Saudi. Thyroid related symptoms were recorded for 1-2 years among 58.1% of the cases and for more than 5 years among 15.8%. Thyroid enlargement was recorded for 73.1% of the cases. The multinodular enlargement was recorded for 53.5% of the cases followed with diffuse thyroid enlargement (27.3%). Regarding the type of surgery undergone, total thyroidectomy was the most recorded followed with lobectomy.Conclusions: The study revealed that the majority of the cases were females at middle age presented with benign lesions with Euthyroid status. The most important conclusion was the significant remarkable underreporting of the different clinical data for the cases with many missing items

    Public awareness of the coronary artery disease and its risk factors in the population of Hail region, Saudi Arabia: a cross-sectional study

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    Background: Coronary Artery Disease (CAD) is a severe cardiovascular complication prevalent in the Kingdom of Saudi Arabia. The risk factors of this disease are so high that it became one of the major causes of mortality among middle-aged individuals. This study aimed to investigate the degree of awareness about risk factors for CAD among the Hail region population.  Methods: The study was carried out in the Hail region, Saudi Arabia, from April 2020 to May 2020. Data collected from five hundred and thirty-seven participants participated through an online survey. The process of selection of participants was through volunteer testing and an online review poll that was disseminated to them to complete. No limitations on age or sex were applied to the surveys.Results: Awareness of TV watching (88.5%), smoking (87.9%), lack of physical activities (78.4%) and family history of CAD (74.7%) as the leading cause of CAD has a notable higher percentage among the studied population whereas the family history of diabetes mellitus (51.6%), having diabetes mellitus (57.7%), family history of hypertension (65.7%) and family history of hyperlipidemia (69.1%) have the lowest percentages. Regarding the gender, the male participants have the poorest awareness degrees about risk factors for the CAD.Conclusion: The study revealed that the family history of hyperlipidemia, Family history of DM, having DM and family history of hypertension have the poorest degrees of awareness of the risk factors for CAD among the studied population.Keywords: Coronary artery disease; Risk factors; Awareness; Hail regio

    Anti-tumor Activity of NuvastaticTM (C5OSEW5050ESA) of Orthosiphon stamineus and Rosmarinic Acid in An Athymic Nude Mice Model of Breast Cancer

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    The current treatment strategies for metastatic breast cancer depend on the cancer subtype by palliating symptoms and prolonging life. However, triple-negative breast cancers have no targeted treatment available. Orthosiphon stamineus (O.s) is a traditional folk medicine plant used in South East Asia to treat many diseases. The aim of this study is to evaluate the anti-tumor activity of O.s extract formulation (ID: C5EOSEW5050ESA trademarked as NuvastaticTM) and its major component, rosmarinic acid in a breast in vivo tumor xenograft model. Human triple-negative breast cancer cells were transplanted into the mammary fat pad of 20 athymic nude mice. Fourteen days post-injection, mice were randomly assigned to four groups. C5EOSEW5050ESA (200 and 400 mg/kg/day) and rosmarinic acid (32 mg/kg/day) were administered orally. The body weight and tumor size were measured twice a week. Histopathological analyses of tumor tissues were conducted. Tumor necrosis and tumor growth were determined by hematoxylin and eosin staining. A significant reduction in tumor size and growth was found in all treatment groups. No significant difference between C5EOSEW5050ESA at 200 mg/kg and rosmarinic acid in the reduction of tumor size and necrosis. However, a more significant reduction was found in tumor growth and necrosis with 400 mg/kg of C5EOSEW5050ESA treatment as compared to other treatments. These results highlighted the anti-tumor activity of C5EOSEW5050ESA in reducing breast tumor growth in mice compared to the lower dose of C5EOSEW5050ESA and rosmarinic acid. This study provides valuable insights into using C5EOSEW5050ESA as a treatment to target triple-negative breast cancers in vivo

    Efficacy of tranexamic acid administration in traumatic brain injury patients: A review

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    BackgroundAnti-fibrinolytic medications decrease traumatic intracranial haemorrhage (ICH). Tranexamic acid (TXA) is an anti-fibrinolytic, which recently has shown effectiveness in management of traumatic haemorrhage‎.AimsTo summarize the randomized control trials (RCTs) that evaluate the efficacy of tranexamic acid administration in traumatic brain ‎injury (TBI) patients‎.‎Methods An electronic literature review, including PubMed, Google Scholar, and EBSCO that examining RCTs, observational, and experimental studies which study the efficacy of TXA administration in (TBI) patients.ResultsThe current review included 7 randomized studies reported the efficacy of TXA in management of TBI. TXA limit secondary brain injury by preventing the expansion of ICH. Administration of TXA exhibited a tendency to decrease head trauma-related mortality.ConclusionTXA significantly lower the risk of ICU expansion m and prevent brain injury related deaths

    The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019

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    Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe

    Adolescent transport and unintentional injuries: a systematic analysis using the Global Burden of Disease Study 2019

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    Background: Globally, transport and unintentional injuries persist as leading preventable causes of mortality and morbidity for adolescents. We sought to report comprehensive trends in injury-related mortality and morbidity for adolescents aged 10–24 years during the past three decades. Methods: Using the Global Burden of Disease, Injuries, and Risk Factors 2019 Study, we analysed mortality and disability-adjusted life-years (DALYs) attributed to transport and unintentional injuries for adolescents in 204 countries. Burden is reported in absolute numbers and age-standardised rates per 100 000 population by sex, age group (10–14, 15–19, and 20–24 years), and sociodemographic index (SDI) with 95% uncertainty intervals (UIs). We report percentage changes in deaths and DALYs between 1990 and 2019. Findings: In 2019, 369 061 deaths (of which 214 337 [58%] were transport related) and 31·1 million DALYs (of which 16·2 million [52%] were transport related) among adolescents aged 10–24 years were caused by transport and unintentional injuries combined. If compared with other causes, transport and unintentional injuries combined accounted for 25% of deaths and 14% of DALYs in 2019, and showed little improvement from 1990 when such injuries accounted for 26% of adolescent deaths and 17% of adolescent DALYs. Throughout adolescence, transport and unintentional injury fatality rates increased by age group. The unintentional injury burden was higher among males than females for all injury types, except for injuries related to fire, heat, and hot substances, or to adverse effects of medical treatment. From 1990 to 2019, global mortality rates declined by 34·4% (from 17·5 to 11·5 per 100 000) for transport injuries, and by 47·7% (from 15·9 to 8·3 per 100 000) for unintentional injuries. However, in low-SDI nations the absolute number of deaths increased (by 80·5% to 42 774 for transport injuries and by 39·4% to 31 961 for unintentional injuries). In the high-SDI quintile in 2010–19, the rate per 100 000 of transport injury DALYs was reduced by 16·7%, from 838 in 2010 to 699 in 2019. This was a substantially slower pace of reduction compared with the 48·5% reduction between 1990 and 2010, from 1626 per 100 000 in 1990 to 838 per 100 000 in 2010. Between 2010 and 2019, the rate of unintentional injury DALYs per 100 000 also remained largely unchanged in high-SDI countries (555 in 2010 vs 554 in 2019; 0·2% reduction). The number and rate of adolescent deaths and DALYs owing to environmental heat and cold exposure increased for the high-SDI quintile during 2010–19. Interpretation: As other causes of mortality are addressed, inadequate progress in reducing transport and unintentional injury mortality as a proportion of adolescent deaths becomes apparent. The relative shift in the burden of injury from high-SDI countries to low and low–middle-SDI countries necessitates focused action, including global donor, government, and industry investment in injury prevention. The persisting burden of DALYs related to transport and unintentional injuries indicates a need to prioritise innovative measures for the primary prevention of adolescent injury. Funding: Bill & Melinda Gates Foundation
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