73 research outputs found
Dynamic modeling of the reactive twin-screw co-rotating extrusion process: experimental validation by using inlet glass fibers injection response and application to polymers degassing
International audienceIn this paper is described an original dynamic model of a reactive co-rotating twinscrew extrusion (TSE) process operated by the Rhodia company for the Nylon-66 degassing finishing step. In order to validate the model, dynamic experiments have been performed on a small-scale pilot plant. These experiments consist in a temporary injection of glass fibers at the inlet of the extruder after it has reached a given operating point. The outlet glass fibers mass fraction time variation is then measured. This experiment does not lead to the RTD measurement. As a matter of fact, due to the high quantity of glass fibers that is introduced, the behavior of the flow through the extruder is perturbed so that the glass fibers cannot be considered as an inert tracer. The dynamic model that we have published elsewhere (Choulak et al., Ind. Eng. Chem. Res., 2004, 43(23), 7373-7382) is adapted to take into account this nonlinear behavior of the extruder with respect to the glass fibers injection and is favorably compared to experimental results. The description of the degassing operation is also included in the model. The model allows simulations of the complete dynamic behavior of the process. When the steady state is reached, the good position of the degassing vent with respect to the partially and fully filled zones positions can also be checked, thus illustrating the way the model can be used for design purposes
Adventurous Physical Activity Environments: A Mainstream Intervention for Mental Health
Adventurous physical activity has traditionally been considered the pastime of a small minority of people with deviant personalities or characteristics that compel them to voluntarily take great risks purely for the sake of thrills and excitement. An unintended consequence of these traditional narratives is the relative absence of adventure activities in mainstream health and well-being discourses and in large-scale governmental health initiatives. However, recent research has demonstrated that even the most extreme adventurous physical activities are linked to enhanced psychological health and well-being outcomes. These benefits go beyond traditional ‘character building’ concepts and emphasize more positive frameworks that rely on the development of effective environmental design. Based on emerging research, this paper demonstrates why adventurous physical activity should be considered a mainstream intervention for positive mental health. Furthermore, the authors argue that understanding how to design environments that effectively encourage appropriate adventure should be considered a serious addition to mainstream health and well-being discourse
Humidity-dependent open-circuit photovoltage from a bacteriorhodopsin/indium tin oxide bioelectronic heterostructure
May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension
Aims
Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries.
Methods and results
Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension.
Conclusion
May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk
Estimating the burden of selected non-communicable diseases in Africa: a systematic review of the evidence
Background
The burden of non-communicable diseases (NCDs) is rapidly increasing globally, and
particularly in Africa, where the health focus, until recently, has been on infectious diseases. The
response to this growing burden of NCDs in Africa has been affected owing to a poor
understanding of the burden of NCDs, and the relative lack of data and low level of research on
NCDs in the continent. Recent estimates on the burden of NCDs in Africa have been mostly
derived from modelling based on data from other countries imputed into African countries, and
not usually based on data originating from Africa itself. In instances where few data were
available, estimates have been characterized by extrapolation and over-modelling of the scarce
data. It is therefore believed that underestimation of NCDs burden in many parts of Africa cannot
be unexpected. With a gradual increase in average life expectancy across Africa, the region now
experiencing the fastest rate of urbanization globally, and an increase adoption of unhealthy
lifestyles, the burden of NCDs is expected to rise. This thesis will, therefore, be focussing on
understanding the prevalence, and/or where there are available data, the incidence, of four major
NCDs in Africa, which have contributed highly to the burden of NCDs, not only in Africa, but
also globally.
Methods
I conducted a systematic search of the literature on three main databases (Medline, EMBASE and
Global Health) for epidemiological studies on NCDs conducted in Africa. I retained and
extracted data from original population-based (cohort or cross sectional), and/or health service
records (hospital or registry-based studies) on prevalence and/or incidence rates of four major
NCDs in Africa. These include: cardiovascular diseases (hypertension and stroke), diabetes,
major cancer types (cervical, breast, prostate, ovary, oesophagus, bladder, Kaposi, liver, stomach,
colorectal, lung and non-Hodgkin lymphoma), and chronic respiratory diseases (chronic
obstructive pulmonary disease (COPD) and asthma). From extracted crude prevalence and
incidence rates, a random effect meta-analysis was conducted and reported for each NCD. An
epidemiological model was applied on all extracted data points. The fitted curve explaining the
largest proportion of variance (best fit) from the model was further applied. The equation
generated from the fitted curve was used to determine the prevalence and cases of the specific
NCD in Africa at midpoints of the United Nations (UN) population 5-year age-group population
estimates for Africa.
Results
From the literature search, studies on hypertension had the highest publication output at 7680, 92
of which were selected, spreading across 31 African countries. Cancer had 9762 publications and
39 were selected across 20 countries; diabetes had 3701 publications and 48 were selected across
28 countries; stroke had 1227 publications and 19 were selected across 10 countries; asthma had
790 publications and 45 were selected across 24 countries; and COPD had the lowest output with
243 publications and 13 were selected across 8 countries. From studies reporting prevalence
rates, hypertension, with a total sample size of 197734, accounted for 130.2 million cases and a
prevalence of 25.9% (23.5, 34.0) in Africa in 2010. This is followed by asthma, with a sample
size of 187904, accounting for 58.2 million cases and a prevalence of 6.6% (2.4, 7.9); COPD,
with a sample size of 24747, accounting for 26.3 million cases and a prevalence of 13.4% (9.4,
22.1); diabetes, with a sample size of 102517, accounting for 24.5 million cases and a prevalence
of 4.0% (2.7, 6.4); and stroke, with a sample size of about 6.3 million, accounting for 1.94
million cases and a prevalence of 317.3 per 100000 population (314.0, 748.2). From studies
reporting incidence rates, stroke accounted for 496 thousand new cases in Africa in 2010, with a
prevalence of 81.3 per 100000 person years (13.2, 94.9). For the 12 cancer types reviewed, a total
of 775 thousand new cases were estimated in Africa in 2010 from registry-based data covering a
total population of about 33 million. Among women, cervical cancer and breast cancer had 129
thousand and 81 thousand new cases, with incidence rates of 28.2 (22.1, 34.3) and 17.7 (13.0,
22.4) per 100000 person years, respectively. Among men, prostate cancer and Kaposi sarcoma
closely follows with 75 thousand and 74 thousand new cases, with incidence rates of 14.5 (10.9,
18.0) and 14.3 (11.9, 16.7) per 100000 person years, respectively.
Conclusion
This study suggests the prevalence rates of the four major NCDs reviewed (cardiovascular
diseases (hypertension and stroke), diabetes, major cancer types, and chronic respiratory diseases
(COPD and asthma) in Africa are high relative to global estimates. Due to the lack of data on
many NCDs across the continent, there are still doubts on the true prevalence of these diseases
relative to the current African population. There is need for improvement in health information
system and overall data management, especially at country level in Africa. Governments of
African nations, international organizations, experts and other stakeholders need to invest more
on NCDs research, particularly mortality, risk factors, and health determinants to have
evidenced-based facts on the drivers of this epidemic in the continent, and prompt better,
effective and overall public health response to NCDs in Africa
Determinants of premature mortality in a city population: An eight-year observational study concerning subjects aged 18–64
Simulating future supply of and requirements for human resources for health in high-income OECD countries
May measurement month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension (vol 40, pg 2006, 2019)
المسألة الحدية ذات النقطتان للمعادلات التفاضلية من الدرجة الثانية ذات البارامتر
في البحث ندرس ايجاد قيمة البارامتر التي تجعل حل المعادلة التفاضلية المتجهة .
d2x = f(t x dx , λ )
dt2 ' dt
X(T) = XT
X(o) = X'(o) = o,
حيث كل من λ x,متجهات في فراع بناخ t, Banach space
تعطي النظرية المثبتة الشروط الكافية لأن يكون لهذه المسألة حل وحيد وكذلك تعطى طريقة الحل بتكوين متسلسلتين . كما تحدد النظرية ايضا سرعة تقارب المتسلسلتان من الحل المضبوط . وفي نهاية البحث تطبق النظرية على مثال للمعادلة التفاضلية المقياسية الخاصة بانحناء كوبولى محمل في نهايته بثقل λ ويبين هذا المثال تطابق شروط النظرية على المسألة المعطاة .
متغير قياس
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