Suitability of commercial barometric pressure sensors to distinguish sitting and standing activities for wearable monitoring

Despite its medical relevance, accurate recognition of sedentary (sitting and lying) and dynamic activities (e.g. standing and walking) remains challenging using a single wearable device. Currently, trunk-worn wearable systems can differentiate sitting from standing with moderate success, as activity classifiers often rely on inertial signals at the transition period (e.g. from sitting to standing) which contains limited information. Discriminating sitting from standing thus requires additional sources of information such as elevation change.The aim of this study is to demonstrate the suitability of barometric pressure, providing an absolute estimate of elevation, for evaluating sitting and standing periods during daily activities. Three sensors were evaluated in both calm laboratory conditions and a pilot study involving seven healthy subjects performing 322 sitting and standing transitions, both indoor and outdoor, in real-world conditions.The MS5611-BA01 barometric pressure sensor (Measurement Specialties, USA) demonstrated superior performance to counterparts. It discriminates actual sitting and standing transitions from stationary postures with 99.5% accuracy and is also capable to completely dissociate Sit-to-Stand from Stand-to-Sit transitions.     

The Springer Model for Lifetime Prediction of Wind Turbine Blade Leading Edge Protection Systems: A Review and Sensitivity Study

The wind energy sector is growing rapidly. Wind turbines are increasing in size, leading to higher tip velocities. The leading edges of the blades interact with rain droplets, causing erosion damage over time. In order to mitigate the erosion, coating materials are required to protect the blades. To predict the fatigue lifetime of coated substrates, the Springer model is often used. The current work summarizes the research performed using this model in the wind energy sector and studies the sensitivity of the model to its input parameters. It is shown that the Springer model highly depends on the Poisson ratio, the strength values of the coating and the empirically fitted a2 constant. The assumptions made in the Springer model are not physically representative, and we reasoned that more modern methods are required to accurately predict coating lifetimes. The proposed framework is split into three parts—(1) a contact pressure model, (2) a coating stress model and (3) a fatigue strength model—which overall is sufficient to capture the underlying physics during rain erosion of wind turbine blades. Possible improvements to each of the individual aspects of the framework are proposed.     

肥厚型心肌病相关代谢基因NCX1对大气混合污染物处理的表达响应

目的检测NCX1基因在大气混合污染物处理下的高血压大鼠(spontaneously hypertensive rats,SHR)心肌中的表达情况,探讨大气混合污染物对肥厚型心肌病的分子影响机制。方法选取80只SHR大鼠随机分为对照组及低、中、高剂量组,分别以1 d、7 d、30 d、60 d、90 d五个时间点进行检测。大鼠染尘每周1次,染毒每天连续进行3.5 h;对照组气管灌注生理盐水,正常呼吸。建模完成后,杀鼠取近左心室处心肌组织提取总RNA,利用实时荧光定量PCR检测NCX1基因表达量。结果 SHR大鼠低中高剂量组中NCX1基因在不同时间段均为高表达,差异有统计学意义(P0.05)。随着处理剂量的增高,NCX1基因相对表达量发生明显变化的时间提前。结论大气混合污染物可能是通过使NCX1基因表达上调,增加胞内钙离子的浓度,使心肌收缩功能发生改变,进而参与肥厚型心肌病的发生与发展。     

Lifetime and six-month prevalence of mental disorders in the Munich follow-up study

Summary The Lifetime and 6 month DSM-III prevalence rates of mental disorders from an adult general population sample of former West Germany are reported. The most frequent mental disorders (lifetime) from the Munich Follow-up Study were anxiety disorders (13.87%), followed by substance (13.51%) and affective (12.90%) disorders. Within anxiety disorders, simple and social phobia (8.01%) were the most common, followed by agoraphobia (5.47%) and panic disorder (2.39%). Females had about twice the rates of males for affective (18.68% versus 6.42%), anxiety (18.13% versus 9.07%), and somatization disorders (1.60% versus 0.00%); males had about three times the rates of substance disorders (21.23% versus 6.11%) of females. Being widowed and separated/divorced was associated with high rates of major depression. Most disordered subjects had at least two diagnoses (69%). The most frequent comorbidity pattern was anxietyand affective disorders. Simple and social phobia began mostly in childhood or early adolescence, whereas agoraphobia and panic disorder had a later average age of onset. The majority of the cases with both anxiety and depression had depression clearly after the occurrence of anxiety. The DIS-DSM-III findings of our study have been compared with both ICD-9 diagnoses assigned by clinicians independently as well as other epidemiological studies conducted with a comparable methodology.     

Distinct large-scale turbulent-laminar states in transitional pipe flow

When fluid flows through a channel, pipe, or duct, there are two basic forms of motion: smooth laminar motion and complex turbulent motion. The discontinuous transition between these states is a fundamental problem that has been studied for more than 100 yr. What has received far less attention is the large-scale nature of the turbulent flows near transition once they are established. We have carried out extensive numerical computations in pipes of variable lengths up to 125 diameters to investigate the nature of transitional turbulence in pipe flow. We show the existence of three fundamentally different turbulent states separated by two distinct Reynolds numbers. Below Re ₁ ≃ 2,300, turbulence takes the form of familiar equilibrium (or longtime transient) puffs that are spatially localized and keep their size independent of pipe length. At Re ₁ the flow makes a striking transition to a spatio-temporally intermittent flow that fills the pipe. Irregular alternation of turbulent and laminar regions is inherent and does not result from random disturbances. The fraction of turbulence increases with Re until Re ₂ ≃ 2,600 where there is a continuous transition to a state of uniform turbulence along the pipe. We relate these observations to directed percolation and argue that Re ₁ marks the onset of infinite-lifetime turbulence.     

Symptomatic fracture incidence in those under 50 years of age in southern Tasmania

OBJECTIVE: To document symptomatic fracture incidence in those aged under 50 years of age. METHODS: Fractures were ascertained from X-ray reports containing the word 'fracture' from all radiology providers for the geographically defined population of southern Tasmania (n = 165 175) for the period 1 July 1997 to 30 June 1999. RESULTS: In the 2-year study frame there were 2943 fractures in 164 730 person years in males and 1348 fractures in 165 620 person years in females. This represents a fracture incidence of 1787 per 100 000 person years in males and 819 per 100 000 person years in females. Peak fracture incidence was 10-14 years in females and 15-19 years in males although different fracture types had varying peak incidence suggesting different fracture-specific causes. The most common fractures were those of the hand (24%), forearm (17%), wrist (10%) and foot (9%). All fractures (including vertebral) were more common in males with relative risks ranging from 1.34 to 4.50. The estimated probability of at least one fracture between birth and 50 years of age was 59% for males and 34% for females. CONCLUSION: There are threefold as many fractures in this age group compared to those due to osteoporosis in the elderly in any given year. More research priority needs to be given to understanding the causes of these fractures so that preventive strategies can be formulated.     

军事飞行人员佩戴视力矫正镜研究进展

目的 综述军事飞行人员佩戴视力矫正镜飞行的研究进展.资料来源与选择该领域的相关研究论文和综述.资料引用国内外公开发表的文献24篇.资料综合综合分析高空低气压、加速度、缺氧、干燥及弹射跳伞等军事航空环境因素对佩戴视力矫正镜的影响,和视力矫正镜在军事航空中的应用.结论 军事飞行人员可以根据不同的机种、职务、任务佩戴不同的视力矫正镜,我军需要尽快开展军事飞行人员佩戴视力矫正镜方面的研究. Abstract： Objective To review the research progress on the practice of wearing corrective spectacles or contact lenses in flying personnel.Literature resource and selection Research papers and reviews in this field.Literature quotation Twenty-four published papers and reviews were cited.Literature synthesis The influences on the military flying personnel with corrective spectacles or contact lenses in aviation environment (atmospheric pressure, acceleration, hypoxia,humidity, ejection, etc.) were analyzed and the application of contact lenses in military aviation medicine was evaluated.Conclusion Military aviator wearing corrective spectacles or contact lenses has a quite long history in western countries and it applies according to aircraft type, flying roles and duty.It is acceptable by flying personnel and enables them with ameliorative visual ability in aviation environment.It is suggested to expand corresponding research and practice in China for dealing with the possible decline of flying personnel's diopter.