Understanding how student-constructed stop-motion animations promote mechanistic reasoning: A theoretical framework and empirical evidence     

Rayendra Wahyu Bachtiar  Ralph F. G. Meulenbroeks  Wouter R. van Joolingen 《科学教学研究杂志》2024,61(2):289-318

Previous studies have documented the promising results from student-constructed representations, including stop-motion animation (SMA), in supporting mechanistic reasoning (MR), which is considered an essential thinking skill in science education. Our current study presents theoretically and empirically how student-constructed SMA contributes to promoting MR. As a theoretical perspective, we propose a framework hypothesizing the link between elements of MR and the construction nature of SMA, that is, chunking and sequencing. We then examined the extent to which this framework was consistent with a multiple-case study in the domain of static electricity involving five secondary school students constructing and using their own SMA creation for reasoning. In addition, students' reasoning in pre- and postconstruction of an SMA was examined. Our empirical findings confirmed our framework by showing that all students identified the basic elements of MR, that is, entities and activities of entities, when engaging in chunking and sequencing. Chunking played a role in facilitating students to identify entities responsible for electrostatic phenomena, and sequencing seemed to elicit students to specify activities of these entities. The analysis of students' reasoning in pre- and postconstruction of SMA found that student-generated SMA has a potential effect on students' retention of the use of MR. Implications for instruction with SMA construction to support MR are discussed.  相似文献   

A Review on the Role of Nutraceuticals as Simple as Se2+ to Complex Organic Molecules Such as Glycyrrhizin That Prevent as Well as Cure Diseases     

Regi Jose  G. R. Sajitha  K. T. Augusti 《Indian journal of clinical biochemistry : IJCB》2014,29(2):119-132

Nutraceuticals are nutritional medicines which are present in edible food items. Most of them are antioxidants with various other biological properties viz, anti inflammatory, anti atherogenic, anticancer, anti viral, anti aging properties etc. They are as simple as minerals like Se²⁺ to complex organic molecules such as glycyrrhizin (Ca²⁺, K⁺ salts of glycyrrhizic acid). They can prevent as well as cure various diseases. Most of the medical people are not aware of the importance of the nutraceuticals as such matters are not part of their text books. Many still think that vitamins are the major nutritional medicines. Actually other dietary principles like terpenes, carotenes, phytosterols, polyphenols, flavanoids, di and poly sulphides, their sulfoxides and their precursor amino acids are necessary to scavenge free radicals in the body which are reactive oxygen species to protect and maintain the vitamin levels in the body. They down regulate the activities of those enzymes which are increased in diseases and they increase those that remove oxidants and detoxify carcinogens. They are immune boosters too. Recently glucosinolates, non toxic alkaloids, certain proteins and even fiber are included in the list of nutraceuticals.  相似文献   

The application of workflow management to digital heritage resources     

Abdullah Al-Barakati  Martin White  Zeeshan Patoli 《International Journal of Information Management》2014

Recent years have witnessed a noticeable proliferation in Digital Library Systems (DLSs) and their specialized form represented in Digital Heritage Resources (DHRs). DHRs usually manage a complex and varied mix of digital heritage objects of different types and formats. They tend to be complex in nature and usually involve complex, simultaneous and intersecting workflows. As a result, DHRs impose implementation challenges on any solutions that aim to manage their workflows. Thus, despite the proliferation of DHRs, it is a noteworthy trend that there is a general lack of workflow management solutions that can be utilized in such systems. As a research area that is rarely covered, this paper therefore presents the design and development of a novel Workflow Management System (WfMS) built to integrate with DHRs specifically, and DLSs in general. In this context, an experimental WfMS aimed to test the validity of workflow management integration with DHRs. The devised WfMS was built as a workflow management solution that can adequately address the specific hurdles imposed by DHR implementations. Additionally, a novel DHR implementation framework called DISPLAYS (Digital Library Services for Playing with Antiquity and Shared Heritage) is presented as a test bed for the proposed WfMS.  相似文献   

Investigation of the heat transfer of a non-Newtonian fluid flow in an axisymmetric channel with porous wall using Parameterized Perturbation Method (PPM)     

H.R. Ashorynejad  K. Javaherdeh  M. Sheikholeslami  D.D. Ganji 《Journal of The Franklin Institute》2014

In the present article Parameterized Perturbation Method (PPM) is used to obtain the solutions of momentum and heat transfer equations of non-Newtonian fluid flow in an axisymmetric channel with porous wall for turbine cooling applications. The validity of the results of PPM solution were verified by comparison with numerical results obtained using a fourth order Runge–Kutta method. These comparisons reveal that Parameterized Perturbation Method is a powerful approach for solving this problem. The analytical investigation is carried out for different governing parameters namely, Reynolds number, injection Reynolds number, Prandtl number and power law index. The results show that skin friction coefficient increases with increase of Reynolds number, especially at high Reynolds numbers. Also it can be found that Nusselt number has direct relationship with Reynolds number, Prandtl number and power law index.  相似文献   

Adaptive output feedback neural network control of uncertain non-affine systems with unknown control direction     

Mohammad M. Arefi  Jafar Zarei  Hamid R. Karimi 《Journal of The Franklin Institute》2014

This paper deals with the problem of adaptive output feedback neural network controller design for a SISO non-affine nonlinear system. Since in practice all system states are not available in output measurement, an observer is designed to estimate these states. In comparison with the existing approaches, the current method does not require any information about the sign of control gain. In order to handle the unknown sign of the control direction, the Nussbaum-type function is utilized. In order to approximate the unknown nonlinear function, neural network is firstly exploited, and then to compensate the approximation error and external disturbance a robustifying term is employed. The proposed controller is designed based on strict-positive-real (SPR) Lyapunov stability theory to ensure the asymptotic stability of the closed-loop system. Finally, two simulation studies are presented to demonstrate the effectiveness of the developed scheme.  相似文献   

Comparison of digoxin concentration in plastic serum tubes with clot activator and heparinized plasma tubes     

Lora Duki?  Ana-Maria ?imundi?  Davorin Malogorski 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2014,24(1):146-150

Introduction:

Sample type recommended by the manufacturer for the digoxin Abbott assay is either serum collected in glass tubes or plasma (sodium heparin, lithium heparin, citrate, EDTA or oxalate as anticoagulant) collected in plastic tubes. In our hospital samples are collected in plastic tubes. Our hypothesis was that the serum sample collected in plastic serum tube can be used interchangeably with plasma sample for measurement of digoxin concentration. Our aim was verification of plastic serum tubes for determination of digoxin concentration.

Materials and methods:

Concentration of digoxin was determined simultaneously in 26 venous blood plasma (plastic Vacuette, LH Lithium heparin) and serum (plastic Vacuette, Z Serum Clot activator; both Greiner Bio-One GmbH, Kremsmünster, Austria) samples, on Abbott AxSYM analyzer using the original Abbott Digoxin III assay (Abbott, Wiesbaden, Germany). Tube comparability was assessed using the Passing Bablok regression and Bland-Altman plot.

Results:

Serum and plasma digoxin concentrations are comparable. Passing Bablok intercept (0.08 [95% CI = −0.10 to 0.20]) and slope (0.99 [95% CI = 0.92 to 1.11]) showed there is no constant or proportional error.

Conclusion:

Blood samples drawn in plastic serum tubes and plastic plasma tubes can be interchangeably used for determination of digoxin concentration.  相似文献   

Social capital as a driver of local knowledge exchange: a social network analysis     

Isabel?Díez-VialEmail author  ángeles?Montoro-Sánchez 《知识管理研究与实践》2014,12(3):276-288

The objective of this paper is to take an in-depth look, from a network perspective, at the role that social capital plays in improving knowledge exchange between organizations. To do this, we consider the three dimensions of social capital: the structural dimension, as measured by the position of firms bridging structural holes; the relational dimension, as gauged by the level of trust and friendship in each relationship; and the cognitive dimension, as estimated by the presence of a shared culture. We also evaluate the level of organizational and human capital present in terms of the firms in the network. Empirical evidence has been gathered from the Madrid Science Park in Spain by applying the social network analysis methodology. The results show that the three dimensions of social capital play a significant role in increasing knowledge exchange in this network, while human and organizational capital differences are only significant for a sub-sample.  相似文献   

Freelancers and the absorption of external knowledge: practical implications and theoretical contributions     

Arjan?KozicaEmail author  Ulrike?Bonss  Stephan?Kaiser 《知识管理研究与实践》2014,12(4):421-431

The term absorptive capacity (AC) describes the process of utilising external knowledge. Although firms are becoming increasingly reliant on highly skilled freelancers as a source of external knowledge, the literature on AC has not incorporated this collaboration for freelancers. In this paper, we address this research deficit in two ways: First, we argue that the ability to collaborate effectively and efficiently with freelancers plays a crucial role in the process of absorbing external knowledge. Second, we argue that the example of freelancers challenges researchers to rethink the conceptualisation of organisational boundaries within the concept of AC. Our paper is based upon previous theoretical insights and exploratory empirical data from a research project on German IT freelancers. For the practice of knowledge management, our paper elaborates upon how organisations can enhance their AC by investing in practices and routines that contribute to successful collaboration with freelancers.  相似文献   

Structuring fragmented knowledge: a case study     

Maria Franca?NoreseEmail author  Fabio?Salassa 《知识管理研究与实践》2014,12(4):454-463

When the need to record and track the point of view of different actors in organizational processes becomes a key point for decision makers, a common representation of knowledge from different perspectives and a map of the situation and the decision and action needs could be useful. A methodology that easily and transparently integrates different ‘soft’ and ‘hard’ tools in a common knowledge structuring approach is proposed to deal with complexities and uncertainties in a socio-technical contest. The purpose of this paper is to show the potentialities of this methodology in a real case, in terms of organizational knowledge acquisition and structuring in a multi-actor public context, a university faculty, in relation to a radical change.  相似文献   

70-year old female patient with mismatch between hematocrit and hemoglobin values: the effects of cold agglutinin on complete blood count     

?erif Ercan  Mustafa ?al??kan  Erhan Koptur 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2014,24(3):391-395

Introduction:

There are a number of pre-analytical and analytical factors, which cause false results in the complete blood count. The present case identifies cold agglutinins as the cause for the mismatch between hematocrit and hemoglobin values.

Materials and methods:

70-year old female patient had a history of cerebrovascular diseases and rheumatoid arthritis. During routine laboratory examination, the patient had normal leukocyte and platelet counts; however, the hemoglobin (Hb: 105 g/L) and hematocrit (HCT: 0.214 L/L) results were discordant. Hemolysis, lipemia and cold agglutinin were evaluated as possible reasons for the mismatch between hematocrit and hemoglobin values.

Results:

First blood sample was slightly hemolysed. Redrawn sample without hemolysis or lipemia was analyzed but the mismatch became even more distinct (Hb: 104 g/L and HCT: 0.08 L/L). In this sample, the titration of the cold agglutinin was determined and found to be positive at 1:64 dilution ratios. After an incubation of the sample at 37°C for 2 hours, reversibility of agglutination was observed.

Conclusion:

We conclude that cold agglutinins may interfere with the analysis of erythrocyte and erythrocyte-related parameters (HCT, MCV, MCH and MCHC); however, Hb, leukocyte and platelet counts are not affected.  相似文献