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1.
India is close to its goal of achieving 100 % school enrolment for children in the age group of 5–16 years. However, this does not correspond with universal school attendance. Not all children who are enrolled attend school regularly. Enrolment is, at best only “nominal” for them. In this study, we examine the ‘demand’ and ‘supply’ side factors behind low attendance by drawing upon a new dataset on adolescents in India- Understanding Adults and Young Adolescents (UDAYA) for Bihar and Uttar Pradesh. Results indicate that girls and older students are more likely to be absent from school. Married girls were more likely to be absent than their unmarried peers. Engaging in unpaid work also deter children from attending school regularly, although surprisingly, there is no significant difference between children who are not working and children engaged in paid work in terms of absenteeism. Religion, affluence, and school type also have a significant influence on attendance. Surprisingly, absenteeism did not emerge to be significant when proficiency in math as a marker of academic performance is taken into consideration. Provisioning of infrastructure can be a particularly effective means towards increasing attendance, as can be the contribution of teachers when considered as positive role models.  相似文献   
2.
We present design, characterization, and testing of an inexpensive, sheath-flow based microfluidic device for three-dimensional (3D) hydrodynamic focusing of cells in imaging flow cytometry. In contrast to other 3D sheathing devices, our device hydrodynamically focuses the cells in a single-file near the bottom wall of the microchannel that allows imaging cells with high magnification and low working distance objectives, without the need for small device dimensions. The relatively large dimensions of the microchannels enable easy fabrication using less-precise fabrication techniques, and the simplicity of the device design avoids the need for tedious alignment of various layers. We have characterized the performance of the device with 3D numerical simulations and validated these simulations with experiments of hydrodynamic focusing of a fluorescently dyed sample fluid. The simulations show that the width and the height of the 3D focused sample stream can be controlled independently by varying the heights of main and side channels of the device, and the flow rates of sample and sheath fluids. Based on simulations, we also provide useful guidelines for choosing the device dimensions and flow rates for focusing cells of a particular size. Thereafter, we demonstrate the applicability of our device for imaging a large number of RBCs using brightfield microscopy. We also discuss the choice of the region of interest and camera frame rate so as to image each cell individually in our device. The design of our microfluidic device makes it equally applicable for imaging cells of different sizes using various other imaging techniques such as phase-contrast and fluorescence microscopy.  相似文献   
3.
总结了《金属学报(英文版)》(简称AMSE)编辑部在建设具有国际学术竞争力和影响力的优秀科技期刊进程中,为提高期刊学术质量进行的新的实践探索,同时分享期刊在数字化和移动互联网发展浪潮中转变服务意识,为提高期刊传播内容质量和传播效率,对已有资源进行二次整合,并与新媒体融合发展的新举措,以期与同行共同寻求科技期刊的发展之路.  相似文献   
4.
土壤湿度对玉米根系生长分布影响的模拟研究   总被引:1,自引:0,他引:1  
为研究土壤湿度对玉米根系生长分布的影响,本文基于辽宁锦州田间土壤湿度控制试验和根系观测实验,利用CERES-Maize作物模型的根系子模型,模拟了不同土壤湿度条件下玉米根系的生长分布情况,结果表明:1土壤湿度适宜条件下,根长密度(单位体积土壤内根的总体长度)模拟效果较好;2水分亏缺条件下,当三叶-拔节期水分亏缺,模拟效果也较好;但是,当拔节-吐丝期以及吐丝-乳熟期水分亏缺,模拟效果均相对较差。针对模拟效果相对较差的情况,发现了根系模型中根分布权重因子wr的计算存在一定的缺陷,即wr中的参数δ(根系分布负指数递减率参数)和参数Zmax(最大根系深度参数)始终为定值(δ=4、Zmax=200cm),没有考虑较差的土壤水分条件对δ和Zmax的影响。针对这一缺陷,探讨性地给出了参数化的改进方案,即适当减小δ或增大Zmax,可以在一定程度上刻画出较差的土壤水分条件对根系生长分布的影响。该参数化的改进方案得到一定的验证:吐丝-乳熟期土壤水分亏缺,参数改进后(δ=1、Zmax=210cm),根长密度模拟值与实测值的相关系数r增大了0.105,线性拟合的RMSE减小了0.119,模拟精度提高;拔节-吐丝期土壤水分亏缺,参数改进后(δ=0),根长密度模拟值与实测值的r增大了0.078,线性拟合的RMSE减小了0.046,模拟精度也提高。  相似文献   
5.
摘要 为研究科学与现有技术对中国传统产业技术创新质量的影响,促进传统产业对科学和现有技术的继承。本文以中药上市企业的中药专利数据为样本,使用零膨胀负二项回归和突变级数法,从静态和动态两个维度分析了中药继承对创新质量影响。发现专利引文数量对创新质量有稳健的消极影响,跨技术领域引证2004年后对创新质量有积极影响,科学引文数量对创新质量随时间由消极影响转变为积极影响,技术标准和古代医药典籍在2003-2004年对创新质量有积极影响,现代医药图书在整体上对创新质量有积极影响。  相似文献   
6.
In this study, we simulated deformation and surfactant distribution on the interface of a surfactant-covered droplet using optical tweezers as an external source. Two optical forces attracted a single droplet from the center to both sides. This resulted in an elliptical shape deformation. The droplet deformation was characterized as the change of the magnitudes of surface tension and optical force. In this process, a non-linear relationship among deformation, surface tension, and optical forces was observed. The change in the local surfactant concentration resulting from the application of optical forces was also analyzed and compared with the concentration of surfactants subjected to an extensional flow. Under the optical force influence, the surfactant molecules were concentrated at the droplet equator, which is totally opposite to the surfactants behavior under extensional flow, where the molecules were concentrated at the poles. Lastly, the quasi-equilibrium surfactant distribution was obtained by combining the effects of the optical forces with the extensional flow. All simulations were executed by the lattice Boltzmann method which is a powerful tool for solving micro-scale problems.  相似文献   
7.
【目的】为国内材料冶金学科期刊和其他传统学科学术期刊国际化提供经验和借鉴。【方法】介绍了《材料科学技术(英文版)》的创刊历史,分析了其与国际同行在稿源、发表周期、知名度等方面存在的差距,并提出了相应的解决办法。【结果】编辑团队坚持"国际化"的办刊方针,面对发展过程中存在的优秀稿件不足、稿件处理速度慢及发表周期长、行业影响力弱等问题,有针对性地长期坚持开展工作,使期刊的行业竞争力和国际影响力均得到持续提升。【结论】针对期刊的具体问题和差距,长期持续不懈地开展工作,即既有"针对性",又要做到"持续性",两者的有机结合,是推动学术期刊不断发展和进步的有效途径。  相似文献   
8.
This paper investigates whether a green kind of design helps firms increase their capabilities for inventing in the environmental domain and whether it does so more than ‘standard’ design. It also investigates whether the effect of ‘green-matching’ between new design and technologies is conditional on firms’ innovative capabilities, as reflected by their R&D expenditure. We address these research questions with respect to the world's top R&D investors, looking at their intellectual property rights at the United States Patent and Trademark Office (USPTO) and proposing an original textual identification of green designs and trademarks. We find that green design increases environmental inventions by top R&D investors, and to a greater extent than non-environmental ones. Standard design also stimulates environmental inventions, but to a lesser extent than green design. The ‘green-matching’ actually helps, but internal innovative capabilities are required to make it effective: a green-tech ‘prize’ emerges from green design, but only once a minimum threshold of R&D expenditure has been reached.  相似文献   
9.
采用测量法、文献资料法、数理统计法和逻辑分析法等,对辽宁省医药类大学生的体质健康进行评价与分析,并从社会学的角度进一步的剖析,探讨家庭、社会以及生活方式对体质健康的影响程度,揭示其体质健康存在的问题和产生的原因,旨在为促进干预对策,提高学生体质健康水平提供理论依据。  相似文献   
10.
科技期刊稿件处理流程优化及其对期刊质量的影响   总被引:1,自引:1,他引:0  
【目的】 采取措施优化稿件处理流程,以保障期刊质量,为科技期刊稿件流程管理提供参考。【方法】 以《应用生态学报》为研究对象,分析了从收稿到排版进行流程优化的措施及其对期刊质量的影响。【结果】 通过缩短流程时间节点、增加初筛环节、调整外审设置、增加作者修改次数、调整主审和终审次数、增加编辑加工和返作者校对次数及改革排版方式,初审和外审周期分别缩短了20天和36~40天,出版周期缩短了4个月,期刊影响因子和被引频次排名稳定,审读结果优良。【结论】 优化后的稿件处理流程缩短了稿件刊发周期,保障了期刊的学术质量和出版质量。  相似文献   
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