64 research outputs found

    Consumo de energía y calidad de servicio en redes WBAN : Una evaluación de desempeño entre capa cruzada e IEEE802.15.4

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    RESUMEN: Dentro de los esquemas de comunicación de redes inalámbricas de área corporal (WBAN), se encuentran los protocolos de capa cruzada, constituidos en una novedosa opción para alcanzar un balance efectivo entre consumo eficiente de energía y métricas de desempeño. En el presente trabajo, evaluamos el desempeño de una estrategia de capa cruzada al compararla contra los protocolos del estándar IEEE802.15.4 en una WBAN. Se evaluó el desempeño de ambas estrategias empleando una simulación de redes WBAN. Luego se ejecutó una comparación estadística y se encontró que la estrategia de capa cruzada ofrece un mejor desempeño con respecto a la compensación entre consumo eficiente de energía y algunas métricas de desempeño en nuestra WBAN. Observamos que en general, la estrategia de capa cruzada supera a ambos modos del estándar IEEE802.15.4 (ranurado y no-ranurado) con respecto a consumo eficiente de energía, retraso extremo a extremo, tasa de pérdida de paquetes y goodput.ABSTARCT: Different communication schemes for Wireless Body Area Networks (WBAN) pretend to achieve a fair tradeoff between efficient energy consumption and the accomplishment of performance metrics. Among those schemes are the Cross-layer protocols that constitute a good choice to achieve the aforementioned tradeoff by introducing novel protocol techniques which are away from the traditional communications model. In this work we assessed the performance of a WBAN cross-layer protocol stack by comparing it against the performance of the protocols of the IEEE802.15.4 standard, which is commonly used for WBAN deployment nowadays. We evaluated the performance of both, cross-layer and IEEE802.15.4 approaches, by means of a simulation, by using a popular network simulator and its frameworks for wireless networks. And then performed a statistical comparison and ascertained that the cross-layer protocol stack offers better performance regarding a tradeoff between efficient energy consumption and performance metrics in our particular test scenario. We observed that, in general, the cross-layer approach outperformed both modes of IEEE802.15.4 standard (slotted and unslotted) regarding energy consumption, end to end delay, packet loss rate and goodput. The results of our experiments reported that the cross-layer strategy saves up to 80% more energy than IEEE802.15.4 unslotted and it is only a 5% below the slotted mode. Regarding the quality of service metrics the performance was always better when using the cross-layer scheme

    Puesta en funcionamiento de NethServer como gestor de servicios basados en GNU/Linux

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    En el siguiente trabajo se implementa el servidor Nethserver el cual permite administración de servicios, con un panel de control que ayuda que permite de una manera fácil e intuitiva la configuración, dependiendo de lo requerimientos del usuario. Este proyecto es enfocado en aprender el manejo de paquetes de Nethserver con el cual se obtiene seguridad en las redes y protege a los usuarios de posibles ataquesIn the following work, the Nethserver server is implemented, which allows service administration, with a control panel that helps in an easy and intuitive configuration, depending on the user's requirements. This project is focused on learning Nethserver packet management with which network security is obtained and users are protected from possible attacks

    Energy consumption and quality of service in WBAN: A performance evaluation between cross-layer and IEEE802.15.4

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    Different communication schemes for Wireless Body Area Networks (WBAN) pretend to achieve a fair tradeoff between efficient energy consumption and the accomplishment of performance metrics. Among those schemes are the Cross-layer protocols that constitute a good choice to achieve the aforementioned tradeoff by introducing novel protocol techniques which are away from the traditional communications model. In this work we assessed the performance of a WBAN cross-layer protocol stack by comparing it against the performance of the protocols of the IEEE802.15.4 standard, which is commonly used for WBAN deployment nowadays. We evaluated the performance of both, cross-layer and IEEE802.15.4 approaches, by means of a simulation, by using a popular network simulator and its frameworks for wireless networks. And then performed a statistical comparison and ascertained that the cross-layer protocol stack offers better performance regarding a tradeoff between efficient energy consumption and performance metrics in our particular test scenario. We observed that, in general, the cross-layer approach outperformed both modes of IEEE802.15.4 standard (slotted and unslotted) regarding energy consumption, end to end delay, packet loss rate and goodput. The results of our experiments reported that the cross-layer strategy saves up to 80% more energy than IEEE802.15.4 unslotted and it is only a 5% below the slotted mode. Regarding the quality of service metrics the performance was always better when using the cross-layer scheme.Dentro de los esquemas de comunicación de redes inalámbricas de área corporal (WBAN), se encuentran los protocolos de capa cruzada, constituidos en una novedosa opción para alcanzar un balance efectivo entre consumo eficiente de energía y métricas de desempeño. En el presente trabajo, evaluamos el desempeño de una estrategia de capa cruzada al compararla contra los protocolos del estándar IEEE802.15.4 en una WBAN. Se evaluó el desempeño de ambas estrategias empleando una simulación de redes WBAN. Luego se ejecutó una comparación estadística y se encontró que la estrategia de capa cruzada ofrece un mejor desempeño con respecto a la compensación entre consumo eficiente de energía y algunas métricas de desempeño en nuestra WBAN. Observamos que en general, la estrategia de capa cruzada supera a ambos modos del estándar IEEE802.15.4 (ranurado y no-ranurado) con respecto a consumo eficiente de energía, retraso extremo a extremo, tasa de pérdida de paquetes y goodput

    Repositioning of the global epicentre of non-optimal cholesterol

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    High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe

    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

    Global variations in diabetes mellitus based on fasting glucose and haemogloblin A1c

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    Fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c) are both used to diagnose diabetes, but may identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening had elevated FPG, HbA1c, or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardised proportion of diabetes that was previously undiagnosed, and detected in survey screening, ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the agestandardised proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global gap in diabetes diagnosis and surveillance.peer-reviewe

    Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

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    From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

    Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants.

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    BACKGROUND: Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories. METHODS: We used data from 1990 to 2019 on people aged 30-79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age. FINDINGS: The number of people aged 30-79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306-359) million women and 317 (292-344) million men in 1990 to 626 (584-668) million women and 652 (604-698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55-62) of women and 49% (46-52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43-51) of women and 38% (35-41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20-27) for women and 18% (16-21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran. INTERPRETATION: Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings. FUNDING: WHO
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