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111.
ABSTRACT

In recent years the concept of the circular economy gained prominence in EU policy-making. The circular economy promotes a future in which linear ‘make-use-dispose’ cultures are replaced by more circular models. In this paper, we use the concept of sociotechnical imaginaries to ask how an imaginary of circularity has been assembled and stabilized, which imaginative resources were drawn on, and how goals, priorities, benefits and risks haven been merged with discourses of innovation, sustainability and growth. Drawing on policy documents and interviews with policy officers of the European Commission, we argue that the monitoring framework and indicator development function as a site collective imagination in which desirable ‘circular’ futures are co-produced. These futures are imagined to provide novel opportunities for the private sector and to generate jobs and economic growth while at the same time improving the natural environment as measured by selected environmental indicators.  相似文献   
112.
This paper studies approximation algorithm for the maximum weight budgeted connected set cover (MWBCSC) problem. Given an element set \(X\), a collection of sets \({\mathcal {S}}\subseteq 2^X\), a weight function \(w\) on \(X\), a cost function \(c\) on \({\mathcal {S}}\), a connected graph \(G_{\mathcal {S}}\) (called communication graph) on vertex set \({\mathcal {S}}\), and a budget \(L\), the MWBCSC problem is to select a subcollection \({\mathcal {S'}}\subseteq {\mathcal {S}}\) such that the cost \(c({\mathcal {S'}})=\sum _{S\in {\mathcal {S'}}}c(S)\le L\), the subgraph of \(G_{\mathcal {S}}\) induced by \({\mathcal {S'}}\) is connected, and the total weight of elements covered by \({\mathcal {S'}}\) (that is \(\sum _{x\in \bigcup _{S\in {\mathcal {S'}}}S}w(x)\)) is maximized. We present a polynomial time algorithm for this problem with a natural communication graph that has performance ratio \(O((\delta +1)\log n)\), where \(\delta \) is the maximum degree of graph \(G_{\mathcal {S}}\) and \(n\) is the number of sets in \({\mathcal {S}}\). In particular, if every set has cost at most \(L/2\), the performance ratio can be improved to \(O(\log n)\).  相似文献   
113.
Many contributions have been made to the field of quality since the inaugural issue of Production and Operations Management in 1992. The first issue called for more research and teaching on TQM, which resulted in two special issues dedicated to TQM. Many other articles related to quality have also been published in the first fifty issues of the journal on topics ranging from technical methods to the Baldrige Award and ISO 9000. As we review these articles, we assess their contribution and the progression of the field of quality. Although past research has advanced our understanding of quality, there still exists many research opportunities in developing more theory, using additional research methodologies, and studying emerging topics in this field.  相似文献   
114.
The Bullwhip Effect is problematic: order variability increases as orders propagate along the supply chain. The fundamental differential delay equations for a retailer's inventory reacting to a surge in demand are solved exactly. Much of the rich and complex inventory behavior is determined by the replenishment delay. The analytical solutions agree with numerical integrations and previous control theory results. Managerially useful ordering strategies are proposed. Exact expressions are derived for the retailer's orders to the manufacturer, and the Bullwhip Effect arises naturally. The approach is quite general and applicable to a wide variety of supply chain problems.  相似文献   
115.
This study tested the hypothesis that married psychiatric outpatients would have lower total health services expenditures than divorced or separated patients. Chart review of the 471 individuals attending an academic medical center outpatient psychiatric clinic during 1994 identified 131 married, 40 separated, and 93 divorced patients. Separated men had significantly higher average total charges ($16,890) than married ($5,279) or divorced ($5,539) men by one-way ANOVA (p < .05). The nonparametric Mann-Whitney test also showed that separated men had higher charges than married or divorced men. There were no differences between marital status groups for women.  相似文献   
116.
The ultimate goal of the research reported in this series of three articles is to derive distributions of doses of selected environmental tobacco smoke (ETS)-related chemicals for nonsmoking workers. This analysis uses data from the 16-City Study collected with personal monitors over the course of one workday in workplaces where smoking occurred. In this article, we describe distributions of ETS chemical concentrations and the characteristics of those distributions (e.g., whether the distribution was log normal for a given constituent) for the workplace exposure. Next, we present population parameters relevant for estimating dose distributions and the methods used for estimating those dose distributions. Finally, we derive distributions of doses of selected ETS-related constituents obtained in the workplace for people in smoking work environments. Estimating dose distributions provided information beyond the usual point estimate of dose and showed that the preponderance of individuals exposed to ETS in the workplace were exposed at the low end of the dose distribution curve. The results of this analysis include estimations of hourly maxima and time-weighted average (TWA) doses of nicotine from workplace exposures to ETS (extrapolated from 1 day to 1 week) and doses derived from modeled lung burdens of ultraviolet-absorbing particulate matter (UVPM) and solanesol resulting from workplace exposures to ETS (extrapolated from 1 day to 1 year).  相似文献   
117.
The Analysis of Verbal Behavior - This research describes a method that initially establishes a mand repertoire as the first component in producing echoic and tact repertoires in young children...  相似文献   
118.
Victimizations from online and offline violence, such as sibling violence, school violence and witness of family violence, both have negative associations with victims' mental health and may share similar individual and family characteristics. This study aims to explore the common and differentiated characteristics in the prediction of school, cyber and family victimization and whether there are unique associations within these victimization types. We employed a two-stage stratified sampling method to collect a representative sample of 5567 children aged 3–17 from a cross-sectional, school-based survey in Hong Kong. Results showed that all types of child victimization, including sibling, school and cyberbullying, as well as the witness of violence at home, were positively correlated with each other. Children's age was positively related to the occurrence and cooccurrence of all types of child victimization. Frequent family residential mobility and parents' higher education level were positively related to all types of children's victimization. The scores of all aspects of children's paediatric quality of life were found negatively related to children's school victimization. This study provides insight into the unique and shared elements of children's online and offline victimization. Knowledge of the distinguished familial gradients of child victimization at home and beyond could benefit the development of child victimization prevention.  相似文献   
119.
120.
We introduce health technology assessment and evidence synthesis briefly, and then concentrate on the statistical approaches used for conducting network meta-analysis (NMA) in the development and approval of new health technologies. NMA is an extension of standard meta-analysis where indirect as well as direct information is combined and can be seen as similar to the analysis of incomplete-block designs. We illustrate it with an example involving three treatments, using fixed-effects and random-effects models, and using frequentist and Bayesian approaches. As most statisticians in the pharmaceutical industry are familiar with SAS? software for analyzing clinical trials, we provide example code for each of the methods we illustrate. One issue that has been overlooked in the literature is the choice of constraints applied to random effects, and we show how this affects the estimates and standard errors and propose a symmetric set of constraints that is equivalent to most current practice. Finally, we discuss the role of statisticians in planning and carrying out NMAs and the strategy for dealing with important issues such as heterogeneity.  相似文献   
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