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11.
GM Foods and the Misperception of Risk Perception 总被引:3,自引:0,他引:3
George Gaskell Nick Allum Wolfgang Wagner Nicole Kronberger Helge Torgersen Juergen Hampel Julie Bardes 《Risk analysis》2004,24(1):185-194
Public opposition to genetically modified (GM) food and crops is widely interpreted as the result of the public's misperception of the risks. With scientific assessment pointing to no unique risks from GM crops and foods, a strategy of accurate risk communication from trusted sources has been advocated. This is based on the assumption that the benefits of GM crops and foods are self-evident. Informed by the interpretation of some qualitative interviews with lay people, we use data from the Eurobarometer survey on biotechnology to explore the hypothesis that it is not so much the perception of risks as the absence of benefits that is the basis of the widespread rejection of GM foods and crops by the European public. Some respondents perceive both risks and benefits, and may be trading off these attributes along the lines of a rational choice model. However, for others, one attribute-benefit-appears to dominate their judgments: the lexicographic heuristic. For these respondents, their perception of risk is of limited importance in the formation of attitudes toward GM food and crops. The implication is that the absence of perceived benefits from GM foods and crops calls into question the relevance of risk communication strategies for bringing about change in public opinion. 相似文献
12.
We propose a multiple imputation method to deal with incomplete categorical data. This method imputes the missing entries using the principal component method dedicated to categorical data: multiple correspondence analysis (MCA). The uncertainty concerning the parameters of the imputation model is reflected using a non-parametric bootstrap. Multiple imputation using MCA (MIMCA) requires estimating a small number of parameters due to the dimensionality reduction property of MCA. It allows the user to impute a large range of data sets. In particular, a high number of categories per variable, a high number of variables or a small number of individuals are not an issue for MIMCA. Through a simulation study based on real data sets, the method is assessed and compared to the reference methods (multiple imputation using the loglinear model, multiple imputation by logistic regressions) as well to the latest works on the topic (multiple imputation by random forests or by the Dirichlet process mixture of products of multinomial distributions model). The proposed method provides a good point estimate of the parameters of the analysis model considered, such as the coefficients of a main effects logistic regression model, and a reliable estimate of the variability of the estimators. In addition, MIMCA has the great advantage that it is substantially less time consuming on data sets of high dimensions than the other multiple imputation methods. 相似文献
13.
Early in development, children explore and combine objects in increasingly complex ways. One manual skill, object construction, represents a major shift in how objects are explored relative to other objects. Despite recent connections with cognitive functioning such as spatial skills, the development of object construction ability has rarely been studied and its trajectory has not been adequately described. The purpose of this study was to describe the development of three types of object construction (stacking, nesting, and affixing) across 5 monthly infant visits and 7 monthly toddler visits using a longitudinal design and a large sample size. Infants (10–14 months, n = 131) and toddlers drawn from the infant sample (18–24 months, n = 65) were given sets of age‐appropriate toys each of which elicited at least one type of constructive play. We described success at different construction tasks and identified trends for construction skill for infant and toddler development using multilevel modeling. We found that each of the three construction actions developed in unique ways across the 10‐ to 24‐month period. Infant construction skill predicted the development of toddler skill, but toddler construction skill diverged from infant trajectories. We discuss the role of combination strategies in the development of object construction skill and how object construction could be related to other domains of development. 相似文献
14.
This article examines how childhood innocence is taken up in (92) memories of undergraduate students across four sites in the US and Canada. Drawing from Foucault's theory of discourse, we examine how three themes—innocence as not knowing, innocence as being provided for, and loss of innocence as exposure to adversity—construct childhood as the absence of conflict, which perpetuates the myth of an innocence/experience binary and encourages a deficit perspective of childhood. These findings contribute to teacher education and childhood studies by highlighting the importance of interrogating adult memories in order to disrupt normative assumptions about children. 相似文献
15.
To recover a low-rank structure from a noisy matrix, truncated singular value decomposition has been extensively used and studied. Recent studies suggested that the signal can be better estimated by shrinking the singular values as well. We pursue this line of research and propose a new estimator offering a continuum of thresholding and shrinking functions. To avoid an unstable and costly cross-validation search, we propose new rules to select two thresholding and shrinking parameters from the data. In particular we propose a generalized Stein unbiased risk estimation criterion that does not require knowledge of the variance of the noise and that is computationally fast. A Monte Carlo simulation reveals that our estimator outperforms the tested methods in terms of mean squared error on both low-rank and general signal matrices across different signal-to-noise ratio regimes. In addition, it accurately estimates the rank of the signal when it is detectable. 相似文献
16.
A number of studies have suggested breastfed infants have improved bonding and attachment or cognitive development outcomes.
However, mechanisms by which these differences might develop are poorly understood. We used maternal time use data to examine
whether exclusively breastfeeding mothers spend more time in close interactive behaviors with their infants than mothers who
have commenced or completed weaning. Mothers (188) participating in a time use survey recorded infant feeding activities for
24 h over a 7 day period using an electronic device. Tracking was conducted at 3, 6, and 9 months postpartum. Data was collected
for maternal activities including infant feeding and time spent in emotional care. The mothers of exclusively breastfed infants
aged 3–6 months fed them frequently and total time spent in breastfeeding averaged around 17 h a week. Maternal time spent
in emotional care was also substantial, and found to correlate positively with time spent breastfeeding. Exclusively breastfed
infants received greatest amounts of emotional care from their mother, and exclusively formula fed infants the least. Mixed
fed infants received more emotional care time than formula fed infants, but less than fully breastfed infants. These findings
may help explain the differential cognitive developmental outcomes reported in the medical literature for breastfed and non
breastfed infants. 相似文献
17.
In recent years, a social identity approach has been used to help understand why people do or do not pay tax [see Taylor, 2003; Wenzel, M., 2002. The impact of outcome orientation and justice concerns on tax compliance: the role of taxpayers’ identity. Journal of Applied Psychology 87, 629–645; Wenzel, M., 2004. An analysis of norm processes in tax compliance. Journal of Economic Psychology 25, 213–228; Wenzel, M., 2005. Misperception of social norms about tax compliance: from theory to intervention. Journal of Economic Psychology 26, 862–883; Wenzel, M., 2007. The multiplicity of taxpayer identities and their implications for tax ethics. Law & Policy 29, 31–50]. This research, which has focused almost exclusively on national identity, indicates that the more people identify with a group, the more likely they are to adhere to its tax norms and values. However, conformity to group norms may be more nuanced than this, and depend on (a) the meaning or content of the identity in question [e.g., Turner, J.C., 1999. Some current themes in research on social identity and self-categorization theories. In: Ellemers, N., Spears, R., Doojse, B. (Eds.), Social Identity: Context, Commitment, Content. Blackwell, Oxford, pp. 6–34] and (b) whether the norms and values are central or peripheral to the content of that identity. In line with this idea, two studies explored whether the concept and act of taxpaying are more central to what it means to be a member of one's nation than of one's occupational group. Both studies confirm this expectation. Importantly, the findings also suggest that although occupational groups have different norms and values in relation to pre-tax behaviours (e.g., how to deal with extra income), these too can be peripheral to what it means to a group member. If norms are peripheral to identity content, conformity to such norms may be independent of group identification. 相似文献
18.
D. C. Wickramarachchi B. L. Robertson M. Reale C. J. Price J. A. Brown 《Australian & New Zealand Journal of Statistics》2019,61(3):380-391
We present an algorithm for learning oblique decision trees, called HHCART(G). Our decision tree combines learning concepts from two classification trees, HHCART and Geometric Decision Tree (GDT). HHCART(G) is a simplified HHCART algorithm that uses linear structure in the training examples, captured by a modified GDT angle bisector, to define splitting directions. At each node, we reflect the training examples with respect to the modified angle bisector to align this linear structure with the coordinate axes. Searching axis parallel splits in this reflected feature space provides an efficient and effective way of finding oblique splits in the original feature space. Our method is much simpler than HHCART because it only considers one reflected feature space for node splitting. HHCART considers multiple reflected feature spaces for node splitting making it more computationally intensive to build. Experimental results show that HHCART(G) is an effective classifier, producing compact trees with similar or better results than several other decision trees, including GDT and HHCART trees. 相似文献
19.
Objective: This study illustrates how a theory-based approach can identify college students’ beliefs about stress reduction activities and help-seeking for depression. These beliefs are the basis for intervention design. Participants: A sample of 53 undergraduate students at a public university in the Midwest participated in this research during March 2016. Methods: An open-ended belief elicitation survey was administered online. Beliefs were identified through qualitative thematic analyses. Results: Exercise was students’ most preferred stress reduction activity. Beliefs about exercise emphasized physical benefits yet also not having time for exercise. Beliefs about help-seeking for depression emphasized treatment efficacy, support from others, stigma, and time constraints. Conclusions: Whereas beliefs about positive outcomes inform educational and motivational messages, beliefs about time constraints underscore the need to also consider structural factors that can help students find time to attend to their well-being. 相似文献
20.
Sophia Price 《International Feminist Journal of Politics》2019,21(1):67-88
This article develops an analysis of the concept of disciplinary neo-liberal feminism through a focus on gendered poverty alleviation strategies and illustrates the value of this through a discussion of microfinance. By locating this study within an analysis of the expansion of global capital accumulation, the article argues that the liberal frameworks of female empowerment and entrepreneurialism that are central to these programs and to feminism in this form, mask their underlying political, social and economic objectives. In contrast, a Marxist Feminist approach more adequately explains the interplay of class and gender that underpins poverty alleviation strategies. This article argues that in the context of financial crisis and reduced social provision, women living in poverty in the Global South were identified as targets for the expansion of global finance. Their integration into global financial networks via microfinance and other pro-poor strategies has facilitated the expansion of markets for credit while at the same time disciplining market participation through the twin forces of risk and incentive. Disciplinary neo-liberal feminism has underpinned this incorporation of women into global capital accumulation creating profound effects for households and families, with microfinance programs representing important sites of contestation for the politics of class and gender. 相似文献