Dynamic radial positioning of a hydrodynamically focused particle stream enabled by a three-dimensional microfluidic nozzle

The ability to confine flows and focus particle streams has become an integral component of the design of microfluidic systems for the analysis of a wide range of samples. Presented here is the implementation of a 3D microfluidic nozzle capable of both focusing particles as well as dynamically positioning those particles in selected flow lamina within the downstream analysis channel. Through the independent adjustment of the three sheath inlet flows, the nozzle controlled the size of a focused stream for 6, 10, and 15 μm polystyrene microparticles. Additional flow adjustment allowed the nozzle to dynamically position the focused particle stream to a specific area within the downstream channel. This unique ability provides additional capability and sample flexibility to the system. In order to gain insight into the fluidic behavior of the system, experimental conditions and results were duplicated within 4.75 μm using a COMSOL Multiphysics^® model to elucidate the structure, direction, proportion, and fate of fluid lamina throughout the nozzle region. The COMSOL Multiphysics model showed that the position and distribution of particles upon entering the nozzle have negligible influence over its focusing ability, extending the experimental results into a wider range of particle sizes and system flow rates. These results are promising for the application of this design to allow for a relatively simple, fast, fully fluidically controlled nozzle for selective particle focusing and positioning for further particle analysis and sorting.     

临沂离区域性金融中心目标有多远——临沂区域金融发展对实体经济支持力度分析

重点研究临沂市银行贷款和股票市场融资对实体经济的支持力度,分析临沂金融发展水平离区域性金融洼地的目标还有多远。数据分析显示,在金融发展的度量指标中,临沂仅境外股票上市融资情况发展良好,而银行业机构贷存比、贷款/GDP比率和境内股票市场上市融资等均发展不足,对实体经济的支持力度不仅落后于山东省内大多数兄弟地市,也显著落后于经济结构类似、可比性较强的浙江省金华市。基于此,提出了包括提高贷存比、发展民间融资等推动临沂金融发展的政策建议。     

Using video analysis to support prospective K-8 teachers’ noticing of students’ multiple mathematical knowledge bases

As part of a larger research project aimed at transforming preK-8 mathematics teacher preparation, the purpose of this study was to examine the extent to which prospective teachers notice children’s competencies related to children’s mathematical thinking, and children’s community, cultural, and linguistic funds of knowledge or what we refer to as children’s multiple mathematical knowledge bases. Teachers’ noticing supports students’ learning in deep and meaningful ways. Researchers designed and enacted a video analysis activity with prospective teachers in their mathematics methods course. The activity served as a decomposition of practice in order to support prospective teachers in engaging in an approximation of the practice of noticing. Our findings showed that prospective teachers evidenced noticing of mathematics teaching and learning as early as the mathematics methods course. We also found that the prompts and structure of the activity supported prospective teachers by increasing their depth of noticing and their foci in noticing, moving from attending primarily to teacher moves (and merely describing what they saw) to becoming aware of significant interactions (and interpreting effects of these interactions on learning). Implications for teacher educators interested in designing and enacting activities to support noticing are discussed.     

A microfluidic shear device that accommodates parallel high and low stress zones within the same culturing chamber

Fluid shear stress (FSS) plays a critical role in regulating endothelium function and maintaining vascular homeostasis. Current microfluidic devices for studying FSS effects on cells either separate high shear stress zone and low shear stress zone into different culturing chambers, or arranging the zones serially along the flow direction, which complicates subsequent data interpretation. In this paper, we report a diamond shaped microfluidic shear device where the high shear stress zone and the low shear stress zone are arranged in parallel within one culturing chamber. Since the zones with different shear stress magnitudes are aligned normal to the flow direction, the cells in one stress group are not substantially affected by the flow-induced cytokine/chemokine releases by cells in the other group. Cell loading experiments using human umbilical vein endothelial cells show that the device is able to reveal stress magnitude-dependent and loading duration-dependent cell responses. The co-existence of shear stress zones with varied magnitudes within the same culturing chamber not only ensures that all the cells are subject to the identical culturing conditions, but also allows the resemblance of the differential shear stress pattern in natural arterial conditions. The device is expected to provide a new solution for studying the effects of heterogeneous hemodynamic patterns in the onset and progression of various vascular diseases.     

Modelica扩展建模的故障诊断技术研究

故障诊断技术是提高故障检测和隔离能力,提高任务可靠性的重要手段,基于模型的故障诊断分析方法得到了广泛应用,但难以用于实时检测诊断,难以计算虚警率等设计指标。本文提出扩展多领域物理系统建模语言Modelica,将多种故障模态嵌入模型中,利用基于假设的真值维护系统(ATMS)方法分析了测试集的生成算法。理论上分析了计算虚警率的可行方案,体现了新模型的优势。     

Visual literacy: A failed metaphor?

Has the visual literacy construct led to useful research and defensible practice? The authors draw on psycholinguistics, pathology, and developmental, cognitive, and cross-cultural social psychology to argue that it has not. A reconceptualization of the inherent assumptions and implications is proposed.     

The realities and imperatives of career counselling for a developing South Africa

Conclusion The modem cash economy has transformed the Africans' traditional meaning structures and work has become a means for the satisfaction of major life tasks—survival, identity, community and meaning (Dovey & Mathabe, 1987) thus creating an urgent need for education for work in schools. School guidance programmes should adopt holistic developmental approach to address career counselling needs adequately.We recommended that a model which can be used in South Africa must address the person-prospective employer fit. It must essentially capture the career needs of individuals and different employers. Such a model must be sensitive to cultural variations across different prospective employees, i.e., it should allow a wide enough definition of careers such that a broad spectrum of experience and interests can be acknowledged.Finally, we recommended that career counselling programmes include a component to facilitate self-liberation and survival of apartheid. Such a self-liberation must include the individual's personal strategies to create meaning in their life.     

Envisioning Our Practice: Examining and Interpreting Pedagogical Visions of Four Early Career Teacher Educators

ABSTRACT

The purpose of this article is to explore how pedagogical visions inform our work as former classroom teachers and current teacher educators in rural and urban regions of the United States. Specifically, we explore the instructional decisions we make as we work to meet these visions in higher education. Teacher educators are charged with the task of fostering visionary teachers in today’s highly challenging educational landscape. We pose the question: How can teacher educators foster visionary beginning teachers without an examination of their visions for their practice? Using a self-study design, we examine the intersections of our pedagogical visions for teaching and the instructional actions we take to work toward our visions in higher education. Findings highlight specific instructional practices and strategies used to enact visions while providing a critical discussion of the lens of visioning within self-study research.     

STEM Motivation Interventions for Adolescents: A Promising Start,but Further to Go

One way to increase students’ participation in science, technology, engineering, and mathematics (STEM) fields is to target their motivation. Researchers have conducted a growing number of interventions addressing students’ motivation in STEM; however, this body of work has not been adequately reviewed. We systematically reviewed experimental and quasi-experimental studies (n = 53) targeting adolescent students’ motivation for STEM subjects. While some interventions showed positive effects on a variety of motivational constructs and academic outcomes, others showed mixed or non-significant effects. We recommend that researchers more frequently examine moderating variables that might limit interventions’ results, including individual-level variables such as gender, contextual-level variables such as the subject in which an intervention was conducted, and design-level variables such as intervention length. Additionally, researchers might better align their interventions with motivation theory. Future research should address these limitations so that the results of successful interventions can better inform educational policy and practice.     

Psychopathology of the physically abusing parent: A comparison with the borderline syndrome

This article compares the psychopathology of the physically abusing parent and that of the borderline patient in four specific areas: common personality characteristics; personal history; psychopathology; and psychodynamics of the abusive act. The first major personality characteristic is the umbrella characteristic of arrested emotional development, the other four characteristics are: poor self image, emotionally isolated, depressive loneliness and poorly suppressed aggression. These correlate with the four major characteristics of the core borderline personality. The personal history for both abusing parents and borderline patients indicate maternal deprivation in preverbal development. The abusing parent's psychopathology is very similar to that of the borderline patient. They both have poor ego strength, a punitive superego and use primitive ego-defenses of denial, splitting and projection. The act of abuse is related to these ego defects but in particular projective identification plays a major role. Further research is indicated and tentative implications are made as regards psychodynamically oriented treatment.