Supporting Online PBL: Design Considerations for Supporting Distributed Problem Solving   总被引：1，自引：0，他引：1  

Chandra Hawley Orrill 《Distance Education》2002,23(1):41-57

This study considers how four groups of education graduate students worked in a distributed problem-based learning (PBL) environment using an asynchronous threaded discussion tool. The analyses consider how the students were able to interact with each other using the tool and how they worked together to define the problem and identify key issues to explore. The outcomes include some design considerations for tools to support these activities as well as insight about how students may work together to solve a problem in a distributed environment.  相似文献   

A cogenerative inquiry using postcolonial theory to envisage culturally inclusive science education     

Jennifer Adams  Bal Chandra Luitel  Emilia Afonso  Peter Charles Taylor 《Cultural Studies of Science Education》2008,3(4):999-1019

This forum constitutes a cogenerative inquiry using postcolonial theory drawn from the review paper by Zembylas and Avraamidou. Three teacher educators from African, Asian and Caribbean countries reflect on problems confronting their professional practices and consider the prospects of creating culturally inclusive science education. We learn that in Mozambique, Nepal and the Caribbean scientism patrols the borders of science education serving to exclude local epistemological beliefs and discourses and negating culturally contextualized teaching and learning. Despite the diverse cultural hybridities of these countries, science education is disconnected from the daily lives of the majority of their populations, serving inequitably the academic Western-oriented aspirations of an elite group who are “living hybridity but talking scientism.” The discussants explore their autobiographies to reveal core cultural values and beliefs grounded in their non-Western traditions and worldviews but which are in conflict with the Western Modern Worldview (WMW) and thus have no legitimate role in the standard school/college science classroom. They reflect on their hybrid cultural identities and reveal the interplay of multiple selves grounded in both the WMW and non-WMWs and existing in a dialectical tension of managed contradiction in a Third Space. They argue for dialectical logic to illuminate a Third Space wherein students of science education may be empowered to challenge hegemonies of cultural reproduction and examine reflexively their own identities, coming to recognize and reconcile their core cultural beliefs with those of Western modern science, thereby dissipating otherwise strongly delineated cultural borders.

Jennifer AdamsEmail:

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Changes in serum copper levels in patients with malignant diseases undergoing radiotherapy     

H. R. Mali  S. A. Siddiqui  Madhur Garg  R. K. Singh  M. L. B. Bhatt 《Indian journal of clinical biochemistry : IJCB》1998,13(1):36-40

Present study repots changes in serum copper levels (SCL) in various neoplastic diseases undergoing radiotherapy. We estimated SCLs in 140 individuals comprising of 90 previously untreated patients with various malignancies and 50 healthy controls. Patients received radiation in doses of 40–70 Gy in 4–7 weeks. SCLs were again estimated in patients following irradiation. The mean SCL was significantly higher (P<0.001) in cancer patients as compared to healthy controls. It declined significantly (P<0.001) following irradiation. However, it remained significantly higher as compared to healthy controls (P<0.01). Highest fall in SCL was seen in complete clinical responders and least in non-responders to radiation treatment. Serial estimation of SCLs may be useful in the treatment monitoring of the neoplasms undergoing radiation treatment.  相似文献   

Protective Role of <Emphasis Type="SmallCaps">l</Emphasis>-Arginine Against Free-Radical Mediated Oxidative Damage in Patients with Unstable Angina     

Tripathi P  Chandra M  Misra MK 《Indian journal of clinical biochemistry : IJCB》2010,25(3):302-306

Unstable angina is a critical condition of heart resulting from narrowing of vessels supplying blood to heart. Ischemia of the myocardium leads to oxidative stress and severe tissue damage. The objective of the present study was to determine the effect of l-arginine administration on the oxidant–antioxidant homeostasis which otherwise gets imbalanced in patients with cardiovascular diseases. The results obtained, show improvement in the oxidant–antioxidant levels of the subjects upon incorporation of l-arginine. Our findings suggest that supplementation of l-arginine along with regular anti-anginal therapy may be beneficial to the patients of unstable angina.  相似文献   

Reconvene and Reconnect the Antioxidant Hypothesis in Human Health and Disease     

Singh PP  Chandra A  Mahdi F  Roy A  Sharma P 《Indian journal of clinical biochemistry : IJCB》2010,25(3):225-243

The antioxidants are essential molecules in human system but are not miracle molecules. They are neither performance enhancers nor can prevent or cure diseases when taken in excess. Their supplemental value is debateable. In fact, many high quality clinical trials on antioxidant supplement have shown no effect or adverse outcomes ranging from morbidity to all cause mortality. Several Chochrane Meta-analysis and Markov Model techniques, which are presently best available statistical models to derive conclusive answers for comparing large number of trials, support these claims. Nevertheless none of these statistical techniques are flawless. Hence, more efforts are needed to develop perfect statistical model to analyze the pooled data and further double blind, placebo controlled interventional clinical trials, which are gold standard, should be implicitly conducted to get explicit answers. Superoxide dismutase (SOD), glutathione peroxidase and catalase are termed as primary antioxidants as these scavenge superoxide anion and hydrogen peroxide. All these three enzymes are inducible enzymes, thereby inherently meaning that body increases or decreases their activity as per requirement. Hence there is no need to attempt to manipulate their activity nor have such efforts been clinically useful. SOD administration has been tried in some conditions especially in cancer and myocardial infarction but has largely failed, probably because SOD is a large molecule and can not cross cell membrane. The dietary antioxidants, including nutrient antioxidants are chain breaking antioxidants and in tandem with enzyme antioxidants temper the reactive oxygen species (ROS) and reactive nitrogen species (RNS) within physiological limits. Since body is able to regulate its own requirements of enzyme antioxidants, the diet must provide adequate quantity of non-enzymic antioxidants to meet the normal requirements and provide protection in exigent condition. So far, there is no evidence that human tissues ever experience the torrent of reactive species and that in chronic conditions with mildly enhanced generation of reactive species, the body can meet them squarely if antioxidants defense system in tissues is biochemically optimized. We are not yet certain about optimal levels of antioxidants in tissues. Two ways have been used to assess them: first by dietary intake and second by measuring plasma levels. Lately determination of plasma/serum level of antioxidants is considered better index for diagnostic and prognostic purposes. The recommended levels for vitamin A, E and C and beta carotene are 2.2–2.8 μmol/l; 27.5–30 μmol/l; 40–50 μmol/l and 0.4–0.5 μmol/l, respectively. The requirement and recommended blood levels of other dietary antioxidants are not established. The resolved issues are (1) essential to scavenge excess of radical species (2) participants in redox homeostasis (3) selective antioxidants activity against radical species (4) there is no universal antioxidant and 5) therapeutic value in case of deficiency. The overarching issues are (1) therapeutic value as adjuvant therapy in management of diseases (2) supplemental value in developing population (3) selective interactivity of antioxidant in different tissues and on different substrates (4) quantitative contribution in redox balance (5) mechanisms of adverse action on excess supplementation (6) advantages and disadvantages of prooxidant behavior of antioxidants (7) behavior in cohorts with polymorphic differences (8) interaction and intervention in radiotherapy, diabetes and diabetic complications and cardiovascular diseases (9) preventive behavior in neurological disorders (10) benefits of non-nutrient dietary antioxidants (11) markers to assess optimized antioxidants status (12) assessment of benefits of supplementation in alcoholics and heavy smokers. The unresolved and intriguing issues are (1) many compounds such as vitamin A and many others possessing both antioxidant and non-antioxidant properties contribute to both the activities in vivo or exclusively only to non-antioxidant activity and (2) since human tissues do not experience the surge of FR, whether there is any need to develop stronger synthetic antioxidants. Theoretically such antioxidants may do more harm than good.  相似文献   

Systems biology     

Karthik Raman  Nagasuma Chandra 《Resonance》2010,15(2):131-153

Systems biology seeks to study biological systems as a whole, contrary to the reductionist approach that has dominated biology. Such a view of biological systems emanating from strong foundations of molecular level understanding of the individual components in terms of their form, function and interactions is promising to transform the level at which we understand biology. Systems are defined and abstracted at different levels, which are simulated and analysed using different types of mathematical and computational techniques. Insights obtained from systems level studies readily lend to their use in several applications in biotechnology and drug discovery, making it even more important to study systems as a whole.  相似文献   

Middle School Teachers’ Use of Mathematics to Make Sense of Student Solutions to Proportional Reasoning Problems     

Erik Jacobson  Joanne Lobato  Chandra H. Orrill 《International Journal of Science and Mathematics Education》2018,16(8):1541-1559

Mathematics teacher education aims to improve teachers’ use of mathematical knowledge to support teaching and learning, an aspect of pedagogical content knowledge (PCK). In this study, we interviewed teachers to understand how they used mathematics to make sense of student solutions to proportional reasoning problems. The larger purpose was to find accurate ways of categorizing teachers’ ability to do this vital aspect of teaching and thereby to inform assessment, teacher education, and professional development. We conjectured that teachers’ PCK for proportional reasoning could be reliably described in terms of attention to quantitative meanings in story problem contexts and in terms of understanding naïve forms of proportional reasoning. Instead, our findings reveal that individual teachers used a variety of means to make sense of (1) cognitively similar student solutions to different tasks and (2) mathematically related steps of a student solution within a single task. These findings illustrate the complexity of PCK for the topic of proportional reasoning and suggest the limits of what can be inferred about teacher knowledge from teachers’ evaluations of student solutions. We discuss implications for teacher education and assessment.  相似文献   

Establishing the overall service quality of engineering education: fuzzy logic approach     

N. Chandra Shekhar  K. Venkatasubbaiah  N. R. Kandukuria 《European Journal of Engineering Education》2012,37(6):575-591

Measuring overall service quality (OSQ) is gaining prominence in higher education due to the increased competition among engineering education institutions (EEIs) and growing awareness about value for money among the public. Determination of OSQ on certain institutional aspects is done by various agencies throughout the world. Each system uses a different set of weighted indicators to measure the overall service quality of institutions. Five service quality factors, namely professionalism, integrated education, facilities, responsiveness and empathy are considered in the study. Trapezoidal fuzzy numbers are used to determine the aggregate weights of the factors to handle the vagueness present in the linguistic values of the stakeholders’ subjective opinions. Final weights of the factors are assessed by taking the distances of each factor between Fuzzy Positive Ideal Rating and Fuzzy Negative Ideal Rating. An illustrative study is presented to determine the OSQ of EEIs. The results help to focus on the factors which need immediate attention to enhance the quality of EEIs.  相似文献   

Projectile motion with quadratic damping in a constant gravitational field     

Chandra Das  Dhiranjan Roy 《Resonance》2014,19(5):446-465

The motion of a projectile in a constant gravitational field is an age-old problem. If there is no resistive force, the problem is simple. However, with the intoduction of resistive forces, the complexity of the problem increases. Recently, there has been a growing interest in the problem of projectile motion under a resistive force proportional to the square of velocity. The problem for resistive force proportional to vv cannot be solved in closed analytical form. A series solution of the equation leads to divergent series for x (t) and y (t) for reasonable values of the initial speed and angle of projection. However, we demonstrate that by inverting the series for x (t), i.e., expressing t in terms of x, and substituting this in y (t) one can express y in terms of x which is a highly convergent series and one can obtain the path of projectile with a few terms of the series. We further demonstrate that one can obtain the path even with a few terms of the divergent series for x (t) and y (t) by using extrapolation methods.  相似文献   

What’s new in computers     

Pramod Chandra P Bhatt 《Resonance》2014,19(6):549-569

Lately there has been a lot of excitement about disruptive forms of ‘money’ — cryptocurrencies. This article traces the evolution of cryptocurrencies focusing on the enabling technologies and some theoretical foundations. We shall also explore the challenges they pose to well-established monetary systems.  相似文献