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61.
In microcirculation, red blood cells (RBCs) flowing through bifurcations may deform considerably due to combination of different phenomena that happen at the micro-scale level, such as: attraction effect, high shear, and extensional stress, all of which may influence the rheological properties and flow behavior of blood. Thus, it is important to investigate in detail the behavior of blood flow occurring at both bifurcations and confluences. In the present paper, by using a micro-PTV system, we investigated the variations of velocity profiles of two working fluids flowing through diverging and converging bifurcations, human red blood cells suspended in dextran 40 with about 14% of hematocrit level (14 Hct) and pure water seeded with fluorescent trace particles. All the measurements were performed in the center plane of rectangular microchannels using a constant flow rate of about 3.0 × 10−12 m3/s. Moreover, the experimental data was compared with numerical results obtained for Newtonian incompressible fluid. The behavior of RBCs was asymmetric at the divergent and convergent side of the geometry, whereas the velocities of tracer particles suspended in pure water were symmetric and well described by numerical simulation. The formation of a red cell-depleted zone immediately downstream of the apex of the converging bifurcation was observed and its effect on velocity profiles of RBCs flow has been investigated. Conversely, a cell-depleted region was not formed around the apex of the diverging bifurcation and as a result the adhesion of RBCs to the wall surface was enhanced in this region.  相似文献   
62.
ABSTRACT

Research in the United States show that professional learning (PL) can improve classroom instruction. However, teachers, especially educators in the content areas, receive insufficient training specific to meeting the language and academic needs of English learners (ELs). The purpose of the current randomized controlled trial (RCT) study was to introduce a high-quality PL program for supporting middle school teachers in teaching science to ELs through classroom observations, so as to evaluate whether in-service science teachers’ instructional delivery can be shaped by intensive, structured, and ongoing PL. Results indicated that after receiving PL, treatment teachers allocated a significantly higher portion of their instructional time in teaching content language, developing students’ expressive language skills, small group and pair activities, implementing strategies evidenced to effective with ELs, and providing more opportunities for students to participate in hands-on activities that were content-related and grade-appropriate. Practical implications for PL were discussed for an international audience.  相似文献   
63.
ABSTRACT

Background

An in-depth understanding of pre-service primary teachers’ progression towards teaching science through inquiry is critical for improving teacher education programmes and, ultimately, improving the quality of science teaching and learning in the classroom.  相似文献   
64.
This paper presents an evaluation of the design and implementation of a course for inservice science teachers, which was undertaken in Seville (1988, Spain) by requirement of the Ministry of Education and based on a didactic model named “Research at School”. The research was designed to evaluate and test the validity of this activity as a strategy to inform teacher educators, and also to encourage their professional development.  相似文献   
65.
International short‐term study tours are a fast‐growing format for outbound education and provide exciting experiential learning opportunities for students in the creative industries disciplines. This success has encouraged researchers to seek a comprehensive view of the various concrete experiences that contribute to student learning during study tours. To that end, this article presents evidence from a qualitative online post‐tour questionnaire administered with students studying various art and design disciplines who participated in short‐term international study tours at a large Australian university in 2015. Using Kolb's Experiential Learning Theory as a framework, data collected explored student perceptions of which concrete experiences on a study tour are most impactful and which may actually hinder learning. Findings revealed: experiencing key industry venues are the most significant aspects of a study tour, rather than networking or personal growth; poor itinerary planning and travel issues are the least liked aspects of a tour, yet are often the most easily addressed with better tour management and planning; and students were positively impacted by unexpected gains in knowledge about their creative industries discipline. This study, therefore, provides unique insights into which concrete experiences may be most impactful as part of the experiential learning cycle within an international study tour for creative industries students.  相似文献   
66.
In this paper a numerical analysis is carried out to obtain the temperature distribution within a single fin. It is assumed that the heat transfer coefficient depends on the temperature. The complete highly non-linear problem is solved numerically and the variations of both, dimensionless surface temperature and dimensionless surface temperature gradient as well as heat transfer characteristics with the governing non-dimensional parameters of the problem are graphed and tabulated.  相似文献   
67.
This systematic review aimed to identify the level of impact of educational strategies for teaching tooth carving on the carving ability of undergraduate dental students. The PubMed-NCBI, Cochrane-CENTRAL, LILACS, Ibecs, BBO, Web of Science, and Scopus databases were searched in May 2019, for randomized controlled trials (RCTs) and two-arm non-randomized studies of interventions (NRSI) addressing educational interventions toward the dental carving of undergraduate students. Studies from the year 2000 until the search date, written in English, Portuguese, and Spanish were included. Study screening and data extraction were performed in duplicate and blinded. The data were presented narratively, considering the dental carving ability of students the primary outcome. The risk of bias was assessed using the RoB tool 2.0 and ROBINS-I, and the level of evidence was determined with GRADE. Of 3,574 studies, 6 were included, with 3 RCTs and 3 NRSIs. Very low level of evidence was provided from the NRSIs that flipped classroom (1 study; n = 140) and a student-driven revised module (1 study; n = 264) improved the carving ability of students. Additionally, there was moderate evidence of online complementary material (1 RCT; n = 30) and reinforcement class improving the carving ability of students (1 RCT; n = 29). The replacement of traditional classes by an instructional DVD (1 RCT; n = 73) and assessment of carving projects through digital systems (1 NRSI; n = 79) did not enhance the carving ability of students. Study design, risk of bias, and imprecision downgraded the level of evidence. There was a very low to moderate evidence on the effectiveness of student-driven educational approaches and complementary classes of dental anatomy in improving the dental carving ability of students.  相似文献   
68.
A connectionist method for autotuning the free parameter of a fractional-order hold (FROH) circuit in order to improve the performance of the digitally controlled systems is proposed. Such a technique employs multilayer perceptrons to approximate the mapping between the sampling period/continuous-time parameters of the estimated plant and the optimal value of the FROH adjustable gain. In this way, adaptive discretization systems to improve the stability properties of the resulting discrete-time zeros are implemented. Simulation results are presented in order to illustrate the properties of the complete system applied to two actual digitally controlled printing devices (HP 7090A and low-cost computer printer).  相似文献   
69.
Science & Education - Our purpose in this article is to discuss the roles for HPSS in Science Education considering the crisis of COVID-19, as well as to think what Science Education could look...  相似文献   
70.
This study addressed the question of what effect bilingual preschool education has on the Spanish and English language development of Spanish speaking children. This question was addressed by measuring the language proficiency of children enrolled in a bilingual preschool program and children who stay at home during the day. Three dimensions of language proficiency were examined: language reception, production, and verbal complexity. Using a repeated measures design, it was found that children enrolled in preschool gained proficiency in English at a faster rate while maintaining a similar level of Spanish proficiency as those children who stay at home during the day. Results of this study are discussed in terms of current issues in the early childhood education of non-English-speaking children.  相似文献   
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