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991.
以硼含量以及Sr/Ba、Sr/Ca 作为指标,计算了东营凹陷南坡沙四段各个沉积时期的古盐度值,盐度垂向上由下到上总体上变小,即湖侵初期盐度较高,湖侵后期盐度变低;平面上东部较高,北部较低,盐度分布受到古水深的控制。古盐度对不同类型的碳酸盐岩具有控制作用,碳酸盐岩所要求的古盐度范围为10.0 ‰ 35.0 ‰,其中白云岩主要分布在古盐度大于15.0 ‰的区域,石灰岩主要分布在古盐度小于20.0 ‰的区域。水体的高盐度为白云岩的形成及成岩转化提供了物质基础和介质条件,在古盐度较高的区域以白云岩沉积为主,或者将已经形成的石灰岩白云岩化;在古盐度较低的区域以石灰岩沉积为主。 相似文献
992.
通过多年持续攻关,塔里木盆地山地地震采集技术取得了长足进展,但仍有许多勘探难题需进一步解决。阐述了针对高大山体区地震资料的低信噪比问题和高陡复杂构造成像问题而提出的一种攻关采集方法。该方法以宽线采集技术为基础,在增强压噪能力、提高静校正精度、改善陡倾角地层成像效果等方面采取了针对性技术措施。这些技术措施的的应用大幅度改善了地震剖面的成像质量。 相似文献
993.
Research on same‐sex relationships has informed policy debates and legal decisions that greatly affect American families, yet the data and methods available to scholars studying same‐sex relationships have been limited. In this article the authors review current approaches to studying same‐sex relationships and significant challenges for this research. After exploring how researchers have dealt with these challenges in prior studies, the authors discuss promising strategies and methods to advance future research on same‐sex relationships, with particular attention given to gendered contexts and dyadic research designs, quasi‐experimental designs, and a relationship biography approach. Innovation and advances in the study of same‐sex relationships will further theoretical and empirical knowledge in family studies more broadly and increase understanding of different‐sex as well as same‐sex relationships. 相似文献
994.
‘Keeping the story alive’: is ethnic and racial dilution inevitable for multiracial people and their children?
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This paper explores how multiracial parents with White partners articulate narratives of ethnic and racial ‘dilution’ and cultural loss in relation to the socialization of their children. In our broader study of how multiracial parents raise their children, we found that parents commonly spoke of concerns around dilution and generational change in relation to four key themes: the loss of cultural knowledge and diminishing practices that connected parents and their children to a minority ancestry; the embodiment of White‐appearing children and the implications of this for family relationships; the use of biological or genetic discourses in relation to reduced blood quantum; and concerns amongst Black/White participants about whitening and the loss of racial consciousness. Parental understandings of dilution varied greatly; some expressed sadness at ‘inevitable’ loss; others were more philosophical about generational change; and others still proactively countered loss through strategies to connect their children to their minority heritages. We show that despite growing awareness of the social constructedness of race and an emergent cosmopolitanism among these parents, discourses of genetics, cultural lineage, and the ‘naturalness’ of race continue to hold sway amongst many multiracial parents. 相似文献
995.
In this paper, we provide some exponential inequalities for extended negatively dependent (END) random variables. By using these exponential inequalities and the truncated method, we investigate the complete consistency for the estimator of nonparametric regression model based on END errors. As an application, the complete consistency for the nearest neighbour estimator is obtained. 相似文献
996.
997.
998.
This paper studies the asymptotic behaviour of the false discovery and non‐discovery proportions of the dynamic adaptive procedure under some dependence structure. A Bahadur‐type representation of the cut point in simultaneously performing a large scale of tests is presented. The asymptotic bias decompositions of the false discovery and non‐discovery proportions are given under some dependence structure. In addition to existing literatures, we find that the randomness due to the dynamic selection of the tuning parameter in estimating the true null rate serves as a source of the approximation error in the Bahadur representation and enters into the asymptotic bias term of the false discovery proportion and those of the false non‐discovery proportion. The theory explains to some extent why some seemingly attractive dynamic adaptive procedures do not outperform the competing fixed adaptive procedures substantially in some situations. Simulations justify our theory and findings. 相似文献
999.
In this article we consider the two-way ANOVA model without interaction under heteroscedasticity. For the problem of testing equal effects of factors, we propose a parametric bootstrap (PB) approach and compare it with existing the generalized F (GF) test. The Type I error rates and powers of the tests are evaluated using Monte Carlo simulation. Our studies show that the PB test performs better than the GF test. The PB test performs very satisfactorily even for small samples while the GF test exhibits poor Type I error properties when the number of factorial combinations or treatments goes up. It is also noted that the same tests can be used to test the significance of random effect variance component in a two-way mixed-effects model under unequal error variances. 相似文献
1000.
We study the scheduling of multiple tasks under varying processing costs and derive a priority rule for optimal scheduling policies. Each task has a due date, and a non‐completion penalty cost is incurred if the task is not completely processed before its due date. We assume that the task arrival process is stochastic and the processing rate is capacitated. Our work is motivated by both traditional and emerging application domains, such as construction industry and freelance consulting industry. We establish the optimality of Shorter Slack time and Longer remaining Processing time (SSLP) principle that determines the priority among active tasks. Based on the derived structural properties, we also propose an effective cost‐balancing heuristic policy and demonstrate the efficacy of the proposed policy through extensive numerical experiments. We believe our results provide operators/managers valuable insights on how to devise effective service scheduling policies under varying costs. 相似文献