Minnesota has been recognized by several studies as a state with a significant amount of racial disparity in its child protection system. This study, using 2001 data from Minnesota's Social Services Information Service, was conducted to determine at which of the six decision points in Minnesota's child welfare system racial disparities are statistically significant. The authors employ a nested model to examine a child's journey through the Minnesota child protection system. Using binary logistic regression, they are able to determine the odds that a child belonging to a particular racial or ethnic group would progress to the next decision point. 相似文献
What does the future hold for the shape of serials to come and for cataloging these and other continuing resources? How should cataloging change to cope with still-unknown types of continuing resources? Will there still be a need for cataloging? For CONSER? For ISSN? How can libraries position themselves to partner with nonlibrary metadata creators in a future linked data environment? Four serials experts discuss these and other questions in a free-ranging conversation about the future of serials cataloging. 相似文献
This study examined the contents of adolescents' hopes and fears for the future in a sample of 1,975 urban and rural 8th, 10th, and 12th graders in China. Chinese adolescents' hopes and fears were most often related to future education, occupation, parental well‐being, marriage and family, academics, leisure activities, wealth, interpersonal relationships, collective issues, and self‐related issues. Urban adolescents compared to rural ones reported more hopes for education and leisure activities and held fewer hopes and fears for parental well‐being and interpersonal relationships. Males reported more hopes and fears for marriage, whereas females reported more hopes and fears for parental well‐being. These results suggest the important role of the social and cultural context in adolescents' future thinking. 相似文献
Urbanization has been shown to strongly affect community composition of various taxa with potentially strong shifts in ecological interactions, including those between hosts and parasites. We investigated the effect of urbanization on the composition of arthropods in nests of great tits in Flanders, Belgium. These nests contain taxonomically and functionally diverse arthropod communities including parasites, predators, detritivores and accidental commensals. Using a standardized hierarchical sampling design with subplots (200 m?×?200 m) nested in plots (3 km?×?3 km) of varying urbanization levels, we collected arthropods from nests of resident great tits after the young had fledged. Arthropods were extracted, identified to Primary Taxonomical Groups (PTG) and counted. Using generalized linear mixed models (GLMMs) we found diverging effects of urbanization on PTG occurrences and abundances at various levels, but we did not find an overall signal in arthropod diversity or richness. Also, visual inspection of non-metric multidimensional scaling (NMDS) plots did not reveal any community differences between urbanization levels at plot or subplot scales. Land use and environmental variables at different distances around nestboxes did not contribute much to the variation between communities. Our results indicate that arthropod nestbox communities are generally not adversely affected by urbanization, and even city gardens and parks harbor comparable communities to forests and suburban areas. We thus found no evidence for a parasite release effect due to urbanization, nor an increased risk of parasitism in human-dominated environments.
Methods for linear regression with multivariate response variables are well described in statistical literature. In this study we conduct a theoretical evaluation of the expected squared prediction error in bivariate linear regression where one of the response variables contains missing data. We make the assumption of known covariance structure for the error terms. On this basis, we evaluate three well-known estimators: standard ordinary least squares, generalized least squares, and a James–Stein inspired estimator. Theoretical risk functions are worked out for all three estimators to evaluate under which circumstances it is advantageous to take the error covariance structure into account. 相似文献
Management has different options for spreading new products. Our study empirically assessed the integral effects of both diffusion and dissemination on innovation adoption. Data on diffusion (as measured by social network density) and on dissemination (as measured by formulating objectives and executing focused activities) was gathered using a questionnaire given to 356 medical specialists, nested in 38 teams. We found both separate and integral effects for diffusion and dissemination. This shows the potential for both engaging the social network structures (diffusion) and adding process measures (dissemination) in order to optimize the innovation spreading process. 相似文献
An increasing number of studies in technology/innovation management contribute to the understanding of the relationship between external technology acquisition and product innovation performance. On the other hand, the meta-analytic reviews of new product development literature indicate a positive impact of product innovativeness on product innovation performance. However, existing research has not examined the link between external technology acquisition and product innovativeness. This study, therefore, aims to fill this gap of knowledge by investigating the external technology acquisition—product innovativeness relationship and examining the moderating roles of R&D investment and configurational context on this link. Based on a panel sample of 105 high-technology firms over a six-year period, a least squared dummy variable s model reveals interesting results. First, external technology acquisition has a positive impact on product innovativeness. Second, R&D investment increases the effect of external technology acquisition on product innovativeness. Lastly, firm size exhibits a negative effect on the contribution of external technology acquisition to product innovativeness. However, firm age positively impacts the relationship between external technology acquisition and product innovativeness. In addition, this study reveals a positive effect of product innovativeness on firm growth. 相似文献
We present algorithms and lower bounds for the Longest Increasing Subsequence (LIS) and Longest Common Subsequence (LCS) problems
in the data-streaming model. To decide if the LIS of a given stream of elements drawn from an alphabet αbet has length at least k, we discuss a one-pass algorithm using O(k log αbetsize) space, with update time either O(log k) or O(log log αbetsize); for αbetsize = O(1), we can achieve O(log k) space and constant-time updates. We also prove a lower bound of Ω(k) on the space requirement for this problem for general alphabets αbet, even when the input stream is a permutation of αbet. For finding the actual LIS, we give a ⌈log (1 + 1/ɛ)-pass algorithm using O(k1+ɛlog αbetsize) space, for any ɛ > 0. For LCS, there is a trivial Θ(1)-approximate O(log n)-space streaming algorithm when αbetsize = O(1). For general alphabets αbet, the problem is much harder. We prove several lower bounds on the LCS problem, of which the strongest is the following: it
is necessary to use Ω(n/ρ2) space to approximate the LCS of two n-element streams to within a factor of ρ, even if the streams are permutations of each other.
A preliminary version of this paper appears in the Proceedings of the 11th International Computing and Combinatorics Conference
(COCOON'05), August 2005, pp. 263–272. 相似文献