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1.
This report summarises the controversy of genetic tests and insurance, with a focus on the UK situation during the past decade. UK experience provides insight for future strategies to help people with genetic disadvantages make insurance provision for themselves and their families. Non-disclosure of genetic test results (already carried out for clinical purposes) may not benefit people at risk of genetic disorders or with positive genetic tests. The pressure of geneticists over a decade to prevent disclosure to insurers may have masked opportunities to use insurance to provide help for people with genetic disadvantages. To seize the opportunities now, there must be collaboration, not conflict. Politicians, geneticists, social scientists and all elements of the insurance industry can contribute to wise solutions.  相似文献   

2.
Pressure transient testing during water injection is undertaken to evaluate the injection potential of a well. If properly interpreted, it can yield information such as effective mobilities of fluids, wellbore damage, and residual oil saturation. This is best done by the simultaneous use of downhole flow-rate and pressure measurements. Analytical solutions obtained under various assumptions for pressure response of an injection well are investigated. For a constant downhole flow rate, it is demonstrated that exact solutions may be obtained for an infinite reservoir during both the injection and the falloff periods. Due to the inherent nonlinearity of the problem, the constant rate solutions are not readily extended for the general case of varying flow rates. Therefore, we have employed an approximate technique. This technique can be used with an altered form of convolution and permits calculation of the pressure response for arbitrary rate data. The range of parameters under which this method may be used are also identified. Computational methods related to convolution are presented. The numerical techniques developed in this paper are sufficiently general that they may be applied to similar well-testing problems involving single-phase flow.  相似文献   

3.
基于CFD的三维轿车车流场的数值计算与应用分析   总被引:2,自引:0,他引:2  
郑春雷  胡寿根 《力学季刊》2001,22(4):416-419
本文以计算流体力学(CFD)为基础,采用有限体积法探求了应用计算流体力学(CFD)研究汽车车身外部流场的可行性。计算机数值解提供了诸如:气动压力场、速度场等车身压力、速度分布以便于获得气动阻力、气动升力和气动侧向力及其由此可得的相关力等信息。三维理想轿车车身空气动力学特性参数的数值模拟结果与风洞实验数据吻合较.好进一步应用于实车分析表明:数值模拟研究汽车空气动力学特性切实可行。  相似文献   

4.
Experimental analyses of thermo-fluid phenomena of micro- and nano-flows with high Knudsen number need the measurement techniques based on interaction of atoms or molecules with photons. The pressure-sensitive paint (PSP) technique has potential as a diagnostic tool for pressure measurement in the high Knudsen number regime because it works as a so-called “molecular sensor”. However, application of PSP to micro devices is very difficult because the conventional PSP is too thick owing to the use of polymer binder and does not have sufficient spatial resolution for pressure measurement of micro-flows. In this study, we have adopted the Langmuir-Blodgett (LB) technique to fabricate pressure sensitive molecular films (PSMFs) using Pd(II) Octaethylporphine (PdOEP) and Pd(II) Mesoporphyrin IX (PdMP) to resolve ordinary PSPs problems, and have tested these PSMFs to evaluate the feasibility of the pressure measurement around micro-devices. It is clarified that the PSMF composed of PdMP has higher sensitivity than that of PdOEP. Since it is also considered that the sensitivity of PSMFs can be increased by introducing arachidic acid (AA) as spacer molecules of LB films to prevent the aggregation of luminescent molecules, we have produced PSMFs with several molar ratio of PdMP to AA. At the most suitable ratio, the PSMF has high sensitivity in the low pressure region with high Knudsen number, even if the amount of the luminescent molecules in the PSMF layer is smaller than that in conventional PSPs. This result indicates that the PSMF is feasible to measure the pressure in high Knudsen number flows such as micro-flows.  相似文献   

5.
The most promising method capable of providing accurate measurements of the first and second normal-stress differences in shear flows at shear rates typical of polymer processing is the so-called hole-pressure method, but its use has not been as widespread as would be expected, namely due to the experimental difficulties associated with performing such experiments accurately. In this work, we use a small-scale modular slit die to assess the practical utility of the method for in-line monitoring of polymer melt flow. We provide a quantitative analysis of intrinsic error sources and use state-of-the-art data acquisition tools to minimize errors associated with pressure transducers. Our results demonstrate that the method can be used to accurately measure the viscosity and first normal-stress difference in melts but probably not the second normal-stress difference because the intrinsic errors are too high, even when the influence of all the potential error sources is minimized or eliminated.  相似文献   

6.
Experiments on unsteady cavitation   总被引:2,自引:0,他引:2  
 The unsteady behaviour of cloud cavitation is obviously influenced by its internal flow pattern. The main purpose of this work is to investigate such a two phase flow during a cavitation cycle. The tests are carried out with a convergent divergent nozzle. Observations are made by using a classical video set in combination with a stroboscopic light sheet. The use of a double optical probe enables void fraction and velocity to be measured inside the two phase flow structure. Data acquisition is governed by a pressure signal measured near the cavity closures to follow their evolution during the shedding process. Special care has been taken in validating the experimental techniques because they have not been used in such flows. The measurements show an extended reversed flow occurring along the solid surface. It plays a significant function in the vapour cloud shedding process. Received: 11 September 1995 / Accepted: 28 June 1996  相似文献   

7.
The need for genetic counselling derives from the peculiarities of genetic information, as compared to other biomedical tests, with particular reference to (a) its predictive character; (b) the existing gap between the ability to diagnose and to treat an inherited disorder, and (c) the psychological, social and ethical problems that genetic testing can raise. Counselling is traditionally performed by healthcare professionals, specifically trained to help individuals to develop ways of dealing with genetic information and gain a better understanding of the problems related with it. The growing number of genetic tests (for rare Mendelian as well as for common disorders), the development of easier and cheaper molecular techniques, the increasing tendency of physicians to have recourse to genetic tests, by-passing alternative diagnostic procedures, are all factors that contribute to the vast increase in the demand for genetic tests, a demand which is significantly out of step with the available numbers of trained counsellors. This paper discusses possible solutions, including the institution of committees with regulatory powers on genetic testing, the promotion of studies on models of genetic services, on programmes to monitor the services currently offered by test providers, and the expansion of training programmes and of employment opportunities for genetic counsellors.  相似文献   

8.
风沙两相流测量技术研究进展   总被引:4,自引:0,他引:4  
杨斌  王元  王大伟 《力学进展》2006,36(4):580-590
围绕风沙两相流的测量, 归纳了过去几十年来在风沙动力学研究中所使用的风速测量技术和输沙率测量装置.着重讨论了高频测量在目前风沙动力学研究中的必要性, 分析了传统风速和输沙率测量装置的优缺点.对新一代光学测量技术------PIV在风沙两相流测量中的应用进行了较为详细的探讨.指出PIV测速技术在风沙两相流研究中具有广泛的应用前景, 使用PIV测速技术可以得到风沙流结构、两相速度场等宏观信息, 同时也可以进行单个颗粒运动状态的研究.   相似文献   

9.
古华光 《力学学报》2017,49(2):410-420
神经系统通过电活动实现信息处理及生物功能,电活动的节律和时空行为是功能的动力学表征.神经电生理实验结合理论模型,借助于分岔揭示了外界激励、参数和噪声调控下的周期、混沌和随机等多样性的节律模式及其节律的复杂转迁规律,揭示了感觉神经对信息(如血压压力信号和痛觉信息)的节律编码机制,揭示了突触噪声扩大脑神经元的信息传递能力并对能力强弱进行了分类,结果可用于提高信息检测能力和指导镇痛;借助于单神经元节律的动力学——如分岔和簇放电节律的快慢动力学——解释了网络功能异常的时空行为,如药物调控脑皮层的螺旋波/癫痫和慢抑制耦合调控的运动网络的同步转迁/运动模式异常,结果给出了调控系统功能的途径;通过大数据分析获得自闭症患者的脑功能网络的时空行为特征——症状相关脑区的同步活动降低,给出了用于诊断的潜在指标.通过新实验发现、新建理论模型、新分析方法和新观点阐释,揭示了神经系统的复杂动力学,认识和解释了神经系统的信息处理机制和异常生物功能/疾病,具有重要科学意义和潜在应用价值.  相似文献   

10.
The Genetics in Primary Care (GPC) project is a USA national faculty development initiative with the goal of enhancing the training of medical students and primary care residents by developing primary care faculty expertise in genetics. Educational strategies were developed for the project by an executive committee with input from an advisory committee, comprising individuals with primary care, medical education and genetics expertise. These committees identified the key issues in genetics education for primary care as (1) considering inherited disease in the differential diagnosis of common disorders; (2) using appropriate counseling strategies for genetic testing and diagnosis, and (3) understanding the implications of a genetic diagnosis for family members. The group emphasized the importance of a primary care perspective, which suggests that the clinical utility of genetic information is greatest when it has the potential to improve health outcomes. The group also noted that clinical practice already incorporates the use of family history information, providing a basis for discussing the application of genetic concepts in primary care. Genetics and primary care experts agreed that educational efforts will be most successful if they are integrated into existing primary care teaching programs, and use a case-based teaching format that incorporates both clinical and social dimensions of genetic disorders. Three core clinical skills were identified: (1) interpreting family history; (2) recognizing the variable clinical utility of genetic information, and (3) acquiring cultural competency. Three areas of potential controversy were identified as well: (1) the role of nondirective counseling versus shared decision-making in discussions of genetic testing; (2) the intrinsic value of genetic information when it does not influence health outcomes, and (3) indications for a genetics referral. The project provides an opportunity for ongoing discussion about these important issues.  相似文献   

11.
压剪复合平板冲击加载技术进展及其应用   总被引:1,自引:0,他引:1  
唐志平 《力学进展》2007,37(3):398-408
自20世纪70年代末发明压剪炮以来, 压剪复合冲击加载实验技术和诊断技术有了长足进展, 应用也日益广泛.由于压剪联合加载波直接反映了材料的动态剪切特性, 对于认识材料的屈服、损伤演化、失效、相变、界面滑移等动态行为和机理, 构筑更全面的本构模型能够提供必要的附加信息.本文主要讨论气炮实验中压剪复合应力波的产生方式, 诊断技术, 以及在压剪复合塑性波和动高压本构模型、聚合物压剪冲击行为、剪切波跟踪法(SWT)和水泥基复合材料的损伤和失效、界面动摩擦行为、冲击相变、动态损伤和断裂等方面的研究与应用进展.   相似文献   

12.
There has been a growing interest in the use of chaotic techniques for enabling secure communication in recent years. This need has been motivated by the emergence of a number of wireless services which require the channel to provide low bit error rates (BER) along with information security. The aim of such activity is to steal or distort the information being conveyed. Optical Wireless Systems (basically Free Space Optic Systems, FSO) are no exception to this trend. Thus, there is an urgent necessity to design techniques that can secure privileged information against unauthorized eavesdroppers while simultaneously protecting information against channel-induced perturbations and errors. Conventional cryptographic techniques are not designed for protecting information integrity when data is being transferred over a harsh communication medium. Hence, a separate channel coding protocol is often necessary to achieve this goal. Our work indicates that the use of a suitable Chaotic Shift Keying (CSK) map combined with an appropriate Space-Time Code (STC) can allow both requirements to be met. In this paper, we have concentrated on investigating the error rate performance of chaotic-wireless optical communication links operating over atmospheric channel, where the turbulence-induced fading is described by the Gamma–Gamma and log–normal distributions. The main aim of the paper is to assess the feasibility of employing Space-Time Coded chaotic communications over Multiple Input Multiple Output (MIMO) communication channels. Our simulations indicate that the combination of the STC and tent map provides the best BER performance in addition to security when compared to the choice of other maps.  相似文献   

13.
OBJECTIVE: The objectives of this study were (1) to explore public experiences, genetic knowledge, expectations of future medical genetic developments, and the attitudes towards the use of genetic information, and (2) to determine whether there are subject characteristics associated with these variables. METHODS: Participants (n = 1,308, age > or = 25 years) of a Dutch consumer panel were sent a questionnaire, specifically designed for this study. RESULTS: Response was 63% (817/1,308). A minority of respondents reported to know someone with a hereditary disease (34%) or to have used a genetic test (8%). Overall, 57% perceived a lack of genetic knowledge. In multivariate analyses, high self-rated knowledge, younger age, having heard of genetic testing, high educational level, female gender, having children living at home, being a health professional, and familiarity with genetic testing were positively associated with genetic knowledge. Future expectations of the consequences of developments in medical genetics varied between the subjects. The great majority expected great benefits for medical practice such as an increasing use of genetic aspects of disease for diagnosis or prevention. One fifth, mainly older people, anticipated a negative impact of genetic developments on society. The results also show that most people are reserved to share their genetic information with others, especially with regard to the wider public domain (e.g. industry and insurers) and employers. Remarkably, respondents were more willing to share their genetic information with scientific researchers (68%) than with their relatives (54%). CONCLUSION: This study suggests that although one fifth anticipates negative consequences of genetic developments, the great majority has high expectations about the increasing use of genetics in prevention, diagnosis and treatment of diseases. In developing educational programmes about genetic innovations in medicine, policymakers will have to take into account pre-existing lay knowledge, views and expectations of different groups of citizens towards these developments.  相似文献   

14.
Static pressure measurement along the centerline of an induced flow ejector   总被引:1,自引:0,他引:1  
Conclusion The static pressure measuring system described in this paper is simple and does not disturb the flow perceptibly. Compared to wall pressure taps, the present measuring system has the advantage of being able to measure the static pressure at any section of the nozzle and to provide a continuous distribution, if necessary. An arrangement using a large number of wall pressure taps can be avoided.In addition, this system allows the internal static pressure of the flow to be measured, which is particularly interesting in the case of two coflowing streams inside an induced flow ejector. The primary jet can be investigated downstream of the primary nozzle exit plane. The static pressure at this exit plane, which is of great importance in numerical simulation of flows in ejectors, can be directly measured by means of this pressure probe (Lu 1986). This system also permits the detection of shock waves in the supersonic stream and gives accurate information about their location, their strength and the lengths of the disturbed areas. Hence, this system is useful for shock structure investigation, especially when flow visualization techniques are impossible to apply (non-transparent walls).However, the use of this measuring system is restricted to relatively short ejectors in order to limit the length of the capillary tube (less than 1.50 m in these experiments) and to minimize its oscillations in the flow.  相似文献   

15.
Structural health monitoring has become an important research topic in conjunction with the damage assessment of structures. The use of system identification approaches for damage detection using inverse methods has become more widespread in recent years and their formulation in a multiobjective framework has become more usual. Inverse problems require the use of an initial baseline model of the undamaged structure. Modelling errors in the baseline model whose effects exceed the modal sensitivity to damage are critical and make an accurate estimation of damage impossible. Artificial intelligence techniques based on genetic algorithms are used increasingly as an alternative to more classical techniques to solve this kind of problem especially due to their feasibility for managing multiobjective problems. This paper outlines an understanding of how particle swarm optimization methods operate in damage identification problems based on multiobjective FE updating procedures and takes modelling errors into account. One experimental example is used to show their performance in comparison with genetic algorithms.  相似文献   

16.
OBJECTIVES: To examine an alternative model for funding genetic health care, on a global basis. METHODS: Internet-based national data on gross domestic product (GDP) per capita, health care funding, and public and private elements of health care costs. RESULTS: Wide variation in GDP per capita and in the proportion available for health care funding. Insufficient funds are available in developing countries. CONCLUSIONS: Health care provision for people with genetic disorders is unlikely to be fully funded unless a different approach to management costs is undertaken. Rare genetic disorders could be funded by an insurance model which may be more equitable and which could be developed to cover the total global health care costs of the genetic disorder.  相似文献   

17.
An improved version of the four-hole directional pressure probe, or Cobra probe, is described, in which the frequency response has been extended to 1.5 kHz. The probe measures all three orthogonal mean and turbulent velocity components at a point in the flow field. The probe also resolves the local mean and turbulent components of static pressure, allowing moments between the fluctuating velocity components and pressure to be determined. The techniques developed to allow the improved frequency response and the use of the probe in turbulent, developed pipe flow (a calibration flow) are described. Also given are the turbulent pressure-velocity correlations, which show a high degree of anticorrelation for one velocity component.  相似文献   

18.
Public and private health insurance plans face the question of whether to cover emerging genetic tests for cancer and other diseases. This paper outlines issues in the economic evaluation of new genetic tests, illustrating key methodological issues and policy implications with findings from a comprehensive and systematic review of the 14 full economic evaluations published over the past 5 years that have addressed both the costs and consequences of molecular genetic tests. Key questions for framing an evaluation include: whose viewpoint matters, which costs and consequences are relevant, and to which clinical alternatives should new genetic tests be compared? While economic evaluation research can inform coverage decisions about genetic tests, the coverage decision-making process must also inform economic researchers about the aims, context, and value systems within which genetic tests will be covered and practised.  相似文献   

19.
This review presents the fundamentals of atomic force microscopy (AFM) with microcantilever probes and their use as fluidic sensors for the measurement of micro/nanoscale transport properties. Over the last two decades, AFM has been widely used for, among other purposes, nanoscale topography, nanomechanical characterization, and intermolecular force spectroscopy. Furthermore, a microcantilever, an essential part of AFM, has been modified and exploited as a mechanical transducer for various sensing applications. Among many prospective uses, there appears to be great potential for micro/nanoscale sensing of fluid density and viscosity (Sect. 3.1), temperature (Sect. 3.2), pressure (Sect. 3.3), and flow velocity (Sect. 3.4). These micro/nanomechanical measurement techniques are expected to complement the advanced optical and electrical measurement techniques currently employed for micro/nanoscale fluidic sensors and also to fill the gap between microscale and nanoscale fluidic transport property measurements.  相似文献   

20.
Flow visualization, particle image velocimetry (PIV), and laser Doppler velocimetry (LDV) are among the most useful tools available for experimental aerodynamics studies. Implementation of these techniques, however, requires that seed material be introduced into the flow. The undesirable qualities of the seeding material often prevent the use of flow visualization and velocimetry techniques in many test environments. This is particularly true for large-scale, closed-circuit tunnels where facility operators must weigh the risks of facility contamination, sensor damage, and safety concerns that might result from the introduction of seed particles. Identification of a practical clean seeding material that minimizes or eliminates these concerns would enable flow visualization and velocimetry techniques to be deployed in these facilities. Here, we demonstrate two seeding systems that have the potential to provide such a solution. The first system is a new concept which uses liquid carbon dioxide that can be made to form discrete particles as it expands from a high-pressure tank. PIV measurements are demonstrated in several flows, including supersonic and subsonic tunnels, using these residue-free seed particles. The second system utilizes a combination of steam and liquid nitrogen to produce an aerosol or fog that serves as flow seeding. Water- or steam-based seeding has been previously demonstrated for flow visualization in subsonic tunnels; here however, we utilize this seed material for PIV and LDV measurements as well as for flow visualization in a large supersonic tunnel.  相似文献   

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