截断正态分布情况下失效概率计算的截断重要抽样法

截断重要抽样法是在传统的重要抽样方法的基础上,引入截断抽样函数来计算结构的失效概率,本文运用此方法来解决工程中普遍存在的截断分布问题。首先将截断分布情况下的可靠性模型转化为非截断分布情况下的多模式并联系统的可靠性模型,然后采用截断重要抽样法求解,推导了截断分布可靠性估计值的方差分析公式。文中给出的算例结果表明:截断重要抽样法适用于截断分布的可靠性分析,且在相同的计算精度下,截断重要抽样法比传统的重要抽样法效率要高。     

Economic considerations for health insurance coverage of emerging genetic tests

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.     

Public attitudes to human gene therapy: a pilot study in Wales

OBJECTIVE: This study aimed to explore some factors influencing perceptions of human gene therapy. METHOD: A small qualitative study using two semi-structured interviews per participant (n = 22). The groups comprised (1) people with cystic fibrosis and members of their family (n = 9), and (2) students from a science evening class as well as lay members of the public selected from the practice list of a local general practitioner (n = 13). RESULTS: This pilot study demonstrates support for somatic gene therapy and ambivalence about germline gene therapy. A clear distinction is drawn between therapy and enhancement, with the majority opposing gene enhancement. CONCLUSIONS: Attitudes towards the acceptability of gene therapy are not necessarily determined by experience of, or exposure to, a genetic condition. More research is needed with the general public to determine what is perceived to be acceptable public policy in this field.     

What role for public health in genetics and vice versa?

Some epidemiologists and geneticists claim that integrating genetics into public health policies and programs is necessary and unavoidable. OBJECTIVE: To examine the extent to which further integration of public health and genetics is warranted. METHODS: Synthesis of the literature in four areas: research, genetic services, regulation, and education. The analysis is limited to human genetics. RESULTS: Public support for basic genetic research has and will continue to lead to new applications and to further understanding of human origins and dispersions. Some applied research, particularly for genetic risk factors for common complex diseases, has low yield and is better supported by private funds. The only genetic service for which a public health role is paramount is newborn screening. With the patenting of genes, and the proliferation of commercial interests in genetic tests and directly advertising them to the public, regulation by public health agencies is increasingly important. As most genetic testing and other services will be provided in the personal health care system, education about genetics is best left to the educational and medical systems. Public health practitioners should be aware of the limitations of genetic tests. CONCLUSIONS: There is little need for further integration of genetic services and education into public health especially in countries in which public and private health services are dichotomized. Newborn screening and follow-up, however, are most safely and effectively provided under public health auspices. The most important area for strengthening the public health role is in the regulation of genetic tests and other genetic services provided primarily by the private sector. Continued support for basic genetic research is needed.     

Community genetics: a bridge between clinical genetics and public health

Clinical genetics and public health differ in their subjects; in who takes the initiative; in their aims, methods and outcome measures, and therefore in their ability to handle sensitive issues. They are seemingly incompatible. Nevertheless, they can be reconciled in community genetics. Community genetics combines the best from clinical genetics and public health. It shares with clinical genetics its aim of empowerment, its methods of information and support, its outcome measures and its possibility to handle sensitive issues. It has in common with public health its subjects; the origin of its initiatives, and non-reproductive prevention. In general, communities can be defined at different levels: geographically, linguistically, socially or genetically. Genetic communities can also be defined at different levels: on the basis of common heritage, on the basis of common practice, or on the basis of common problems.     

The Integration of Genomics into Public Health Research, Policy and Practice in the United States

Objectives: To examine the opportunities for and responsibilities of the public health community in bridging the gap between gene discovery and the application of genetic information to improve health and prevent disease. Methods: We developed genetics-related definitions for the core functions and essential services of public health. We combined these definitions with a visual model to create one possible 'blueprint' for integrating genomics into public health activities. Results: The proposed blueprint and accompanying examples illustrate the important role for genomics throughout public health research, policy and practice. Further refinement and implementation of this blueprint represents an ambitious public health leadership agenda. Conclusions: Opportunities for immediate action include strategic planning for the integration of genomics across programs, developing genomics competencies among health professionals, enhancing surveillance and epidemiologic capacity to aid evidence-based policy making, building partnerships and seeking input from stakeholders and incorporating information about genomics into health communications. Copyright 2001 S. Karger AG, Basel     

Public knowledge and public trust

As health care applications derived from human genetics research are likely to move increasingly from 'clinic to community', there is growing interest not just in how patients understand and take up health-related genetic information but also in the views of the wider population, as well as a range of professional groups. In this paper, issues relating public knowledge and public trust are raised and discussed in an attempt to move forward debates about public involvement in genomic research and the role of sociologists within interdisciplinary teams. As the field of public understanding of science has developed, we have seen a shift from a focus on the lack of scientific literacy as problem to a recognition of the range of different knowledges that people have and use as they confront science and technology in their everyday lives. As a mood for dialogue pervades many institutions in their relations with 'publics', attention must now be paid to the way in which knowledge and expertise is expressed, heard and acted upon in dialogic encounters. There is increasing concern about public trust in science and calls to increase public confidence, particularly through more open engagement with a range of publics. However, lack of trust or loss of confidence may be constructed as problems rather than reflecting empirical reality, where more complex relationships and attitudes prevail. Lack of trust is often privatized, deeply rooted in lived experience and routinely managed. Trust relations are generally characterized by ambivalence, uncertainty and risk, and are always provisional. Drawing on selected literature and empirical research to review and illustrate this field, this paper argues that scepticism or ambivalence on the part of publics are not necessarily problems to be overcome in the interest of scientific progress, but rather should be mobilized to enhance open and public debates about the nature and direction of genomics research, medicine, and the related social and ethical issues. Just as there can be no resolute expression of public knowledge or public opinion, it is unlikely that there is a resolute expression of public trust in genomics. However, ambivalence and scepticism can be harnessed as powerful resource for change, whether through the mobilization of public knowledges or the development of greater reflexivity within scientific institutions. This demands a sharing of power and greater public involvement in the early stages of policy formation and scientific and medical agenda setting.     

Public knowledge, public trust: understanding the 'knowledge deficit'

This article examines the 'knowledge deficit' model, which still persists in liberal, technological societies. It is based upon the assumption that expert forms of knowledge, both in the sciences and the humanities, provide a sufficient basis for deciding the most important public policy questions. In this view, public perceptions and beliefs that run counter to this expert knowledge provide unacceptable justifications for public policies. Instead, support of expert knowledge needs to be 'built' through education and public relations strategies. This view is challenged on the basis of basic democratic theory, using the debate about genetically modified maize in Mexico as an example. 'Knowledge deficits' also exist on the side of experts.     

Community genetic services in Latin America and regional network of medical genetics. Recommendations of a World Health Organization consultation

The World Health Organization sponsored a Consultation on Community Genetic Services and a Regional Network of Medical Genetics in Latin America in Porto Alegre, Brazil, on June 19, 2003. The main recommendations of the meeting included: (a) the call for government funding of services, research and education in medical genetics; (b) the conduct of epidemiological research on the prevalence and types of birth defects, genetic disorders and genetic predispositions to common diseases; (c) the education of health professionals in genetics; (d) the education of genetic professionals in community health and public health genetics; (e) the fostering of interactions between clinical geneticists, public health personnel, primary health care workers and community organizations, and (f) a better planning of regionalized services to avoid duplication and inefficiency.     

Medical genetic services in the state of Rio de Janeiro, Brazil

Rio de Janeiro is a state with close to 15 million inhabitants and approximately 250,000 births per year. The state counts nine clinical genetic units in public institutions, providing for 9,400 outpatient consultations yearly, which is insufficient to cover the estimated needs. Laboratory tests such as cytogenetics, inborn errors of metabolism and molecular studies are available on a limited basis. Newborn screening in the public health system is being performed for phenylketonuria, congenital hypothyroidism and sickle cell disease. In the state there are also special treatment programs for osteogenesis imperfecta and Gaucher's disease, subsidized by the Brazilian Ministry of Health. Presently, efforts of medical geneticists are concentrated on highlighting the practical relevance of clinical genetics, and the need to integrate the specialty into the public health system in a functional network of genetic services.     

Public engagement as a means of restoring public trust in science--hitting the notes, but missing the music?

This paper analyses the recent widespread moves to 'restore' public trust in science by developing an avowedly two-way, public dialogue with science initiatives. Noting how previously discredited and supposedly abandoned public deficit explanations of 'mistrust' have actually been continually reinvented, it argues that this is a symptom of a continuing failure of scientific and policy institutions to place their own science-policy institutional culture into the frame of dialogue, as possible contributory cause of the public mistrust problem.     

Genetics and global health care

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.     

Social, political, and epistemological aspects of genetics and genomics

The papers in this special issue were first given at a conference in Toronto, Canada, in April 2004 entitled 'Genomics, Genetics, and Society: Bridging the Disciplinary Divides'. The papers fall into four intersecting themes. (1) The introduction of genetic and genomic technologies into communities. (2) Governance, the morals of scientific discourse and policy making. (3) What is a gene? (4) Public knowledge, public trust and improved dialogue between the public and scientists.     

The quality of media reports on discoveries related to human genetic diseases

OBJECTIVES: To examine (1) the quality of media reports (newspapers, television and public radio) of genetic discoveries with medical relevance and (2) factors related to the completeness and balance of the stories. METHODS: Analysis of the accuracy, balance, and completeness of 228 media stories reporting 24 genetic discoveries between 1996 and 2000 using a previously validated instrument. RESULTS: Although usually accurate, the stories contained only 45.5 +/- 13.8% (mean +/- SD) of relevant items. Stories appearing on television and stories reporting discoveries of genes for rare diseases were the least complete. Stories in non-US English-speaking newspapers included more content items per word than US stories. Less balanced stories exaggerated the benefits of discoveries, ignored possible risks, and did not present a range of expert opinion. Scientists were sometimes the source of exaggeration. CONCLUSIONS: To increase the quality of media reports about genetic discoveries, stories should include more relevant items and be written by journalists skilled in science writing. Scientists will have to resist the tendency to exaggerate. These conclusions may apply to media stories of other discoveries as well.     

HUGO urges genetic benefit-sharing

In view of the fact that for-profit enterprise exceeds public expenditures on genetic research and that benefits from the Human Genome Project may accrue only to rich people in rich nations, the HUGO Ethics Committee discussed the necessity of benefit-sharing. Discussions involved case examples ranging from single-gene to multi-factorial disorders and included the difficulties of defining community, especially when multifactorial diseases are involved. The Committee discussed arguments for benefit-sharing, including common heritage, the genome as a common resource, and three types of justice: compensatory, procedural, and distributive. The Committee also discussed the importance of community participation in defining benefit, agreed that companies involved in health have special obligations beyond paying taxes, and recommended they devote 1-3% of net profits to healthcare infrastructure or humanitarian efforts.     

Public experiences, knowledge and expectations about medical genetics and the use of genetic information

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.     

Flexibility and attractors in context: family emotion socialization patterns and children's emotion regulation in late childhood

Familial emotion socialization practices relate to children's emotion regulation (ER) skills in late childhood, however, we have more to learn about how the context and structure of these interactions relates to individual differences in children's ER. The present study examined flexibility and attractors in family emotion socialization patterns in three different conversational contexts and their relation to ER in 8-12 year olds. Flexibility was defined as dispersion across the repertoire of discrete emotion words and emotion socialization functions (emotion coaching, dismissing, and elaboration) in family conversation, whereas attractors were defined as the average duration per visit to each of these three emotion socialization functions using state space grid analysis. It was hypothesized that higher levels of flexibility in emotion socialization would buffer children's ER from the presence of maladaptive attractors, or the absence of adaptive attractors, in family emotion conversation. Flexibility was generally adaptive, related to children's higher ER across all contexts, and also buffered children from maladaptive attractors in select situations. Findings suggest that the study of dynamic interaction patterns in context may reveal adaptive versus maladaptive socialization processes in the family that can inform basic and applied research on children's regulatory problems.     

The Cancer Genetics Network: recruitment results and pilot studies

OBJECTIVE: The National Cancer Institute established the Cancer Genetics Network (CGN) to support collaborative investigations into the genetic basis of cancer susceptibility, explore mechanisms to integrate this new knowledge into medical practice, and identify ways of addressing the associated psychosocial, ethical, legal, and public health issues. SUBJECTS AND METHODS: The CGN has developed the complex infrastructure required to support the projects, including the establishment of guidelines and policies, uniform methods, standard questionnaires to be used by all of the centers, and a standard format for submission of data to the Informatics Center. Cancer patients and their family members have been invited to enroll and be included in a pool of potential study participants. The Information Technology Group is responsible for support of the design, implementation, and maintenance of the multicenter Network-wide research protocols. RESULTS: As of January 2004, the CGN contained data on 23,995 probands (participants) and 425,798 family members. As a resource for cancer genetic studies, the CGN has a large number of probands and first-degree relatives with and without cancer and with multiple ethnicities. Different study designs can be used including case-control, case-case, and family studies. CONCLUSIONS: The unique resources of the CGN are available for studies on cancer genetic susceptibility, translational research, and behavioral research. The CGN is now at a point where approved collaborators may have access to enrolled patients and their families for special studies, as well as to the clinical, environmental and family cancer history data banked in the Informatics Center.     

Application of wake oscillators to two-dimensional vortex-induced vibrations of circular cylinders in oscillatory flows

A nonlinear time-domain simulation model for predicting two-dimensional vortex-induced vibration (VIV) of a flexibly mounted circular cylinder in planar and oscillatory flow is presented. This model is based on the utilization of van der Pol wake oscillators, being unconventional since wake oscillators have typically been applied to steady flow VIV predictions. The time-varying relative flow–cylinder velocities and accelerations are accounted for in deriving the coupled hydrodynamic lift, drag and inertia forces leading to the cylinder cross-flow and in-line oscillations. The system fluid–structure interaction equations explicitly contain the time-dependent and hybrid trigonometric terms. Depending on the Keulegan–Carpenter number (KC) incorporating the flow maximum velocity and excitation frequency, the model calibration is performed, entailing a set of empirical coefficients and expressions as a function of KC and mass ratio. Parametric investigations in cases of varying KC, reduced flow velocity, cylinder-to-flow frequency ratio and mass ratio are carried out, capturing some qualitative features of oscillatory flow VIV and exploring the effects of system parameters on response prediction characteristics. The model dependence of hydrodynamic coefficients on the Reynolds number is studied. Discrepancies and limitations versus advantages of the present model with different feasible solution scenarios are illuminated to inform the implementation of wake oscillators as a computationally efficient prediction model for VIV in oscillatory flows.