263 research outputs found
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MOOCs for Development? A Study of Indian Learners and their Experiences in Massive Open Online Courses
The study outlined in this thesis provides an account of the demographics, motivations and experiences of Indian learners in Massive Open Online Courses (MOOCs) comparing the UK-based platform FutureLearn and the Indian platform NPTEL (The National Programme on Technology Enhanced Learning).
A sequential mixed-methods approach was adopted. A web-based survey (n=2373) was used to collect demographical data and evidence of respondents’ perceptions about their motivations for taking a MOOC, their learning experiences, and any challenges they may have faced while taking a MOOC. The survey phase was followed by 30 semi-structured interviews with learners from both platforms, adding a rich level of qualitative data to the study, revealing the varied experiences and backgrounds of MOOC learners from India.
Analysis of the collected data suggests that learners from India tend to be male, younger, more likely to be in formal education, and more educated than participants featured in many existing studies on MOOC learner demographics. Further, the current study outlined several demographic and motivational differences between learners on FutureLearn and NPTEL, likely to be attributable to the distinct objectives of the two platforms.
A more in-depth exploration of learners’ experiences suggested that a diverse group of people, particularly on the FutureLearn platform, are using MOOCs to learn more about areas of personal interest, and, in some cases, using FutureLearn resources to assist in their teaching practice. Conversely, learners on the NPTEL platform, who tended to experience more technical challenges such as connectivity issues, were using MOOCs as a supplement to their formal studies, to make up for some of the systemic lack of quality education in many Indian universities.
This thesis suggests that educational technology, in the form of MOOCs, might not necessarily be widening participation in education in a Global South context like India. However, it offers a unique insight into the experiences of learners from India, and provides practical recommendations on how best to serve the needs of the varied Indian learners that make use of MOOCs
The development of the Indian iron and steel industry.
Thesis (M.B.A.)--Boston Universit
Physiological consequences of astrocyte-to-neuron signaling
The traditional view of the central nervous system (CNS) in which only neurons are capable of active intercellular signaling while glial cells merely provide structural and trophic support to neurons, has been challenged by a number of new findings. Recent evidence shows that astrocytes, a subtype of glial cells, participate in inter-astrocyte signaling by using variations in their cytosolic Ca2+ levels (Cornell-Beil et al., 1990; Charles et al., 1991; Finkbeiner et al., 1992; Duffy and MacVicar, 1995). Neuronal activity can trigger these Ca2+ increases in astrocytes indicating that neurons can signal to astrocytes (Dani et al., 1992; Porter and McCarthy, 1996; Pasti et al., 1997). Finally, the demonstration that Ca2+ elevations in astrocytes evoke glutamate release from them and subsequent glutamate-dependent Ca2+ elevations in adjacent neurons, have raised the exciting possibility that astrocytes may in turn, signal back to neurons (Nedergaard et al., 1994; Parpura et al., 1994; Charles et al., 1994; Hassinger et al., 1995; Pasti et al., 1997; Bezzi et al., 1998);Although the existence of astrocyte to neuron signaling has been firmly established by these Ca2+ imaging studies, the physiological consequences of this signaling have not been elucidated. The work presented in this dissertation, provides electrophysiological evidence for the astrocyte-neuron signaling and demonstrates that stimulation of astrocytes leads to Ca2+ increases in astrocytes which modulates neuronal currents and synaptic transmission in hippocampal cultured new-ons (Araque et al., 1998a,b). A variety of stimuli that increase the intracellular Ca2+ levels in astrocytes, such as mechanical or electrical stimulation and application of the neuroligand prostaglandin E2, generate a glutamate-dependent slow inward current (SIC) mediated through the NMDA and non-NMDA glutamate receptors and/or an increase in the frequency of the miniature synaptic currents through the NMDA receptors in adjacent neurons. Additionally, stimulation of astrocytes transiently reduces the amplitude of the action potential-evoked postsynaptic current mediated through the metabotropic glutamate receptors;This work proposes a new view of the nervous system in which neurons and astrocytes exist as a network in which bidirectional communication takes place
Ka-band MMIC microstrip array for high rate communications
In a recent technology assessment of alternative communication systems for the space exploration initiative (SEI), Ka-band (18 to 40 GHz) communication technology was identified to meet the mission requirements of telecommunication, navigation, and information management. Compared to the lower frequency bands, Ka-band antennas offer higher gain and broader bandwidths; thus, they are more suitable for high data rate communications. Over the years, NASA has played an important role in monolithic microwave integrated circuit (MMIC) phased array technology development, and currently, has an ongoing contract with Texas Instrument (TI) to develop a modular Ka-band MMIC microstrip subarray (NAS3-25718). The TI contract emphasizes MMIC integration technology development and stipulates using existing MMIC devices to minimize the array development cost. The objective of this paper is to present array component technologies and integration techniques used to construct the subarray modules
BRST-antifield-treatment of metric-affine gravity
The metric-affine gauge theory of gravity provides a broad framework in which
gauge theories of gravity can be formulated. In this article we fit
metric-affine gravity into the covariant BRST--antifield formalism in order to
obtain gauge fixed quantum actions. As an example the gauge fixing of a general
two-dimensional model of metric-affine gravity is worked out explicitly. The
result is shown to contain the gauge fixed action of the bosonic string in
conformal gauge as a special case.Comment: 19 pages LATEX, to appear in Phys. Rev.
Clinical profile of heart failure in Beta-Thalassaemia Major (ß-TM): Case studies with current consideration and future perspectives
Background: Cardiac involvement is a major cause of mortality in Beta-Thalassaemia Major (ß-TM) patients. Despite many advances in therapeutic management of ß-TM, cardiac involvement remains the primary cause of mortality in ~70% of the cases. Chronic iron overloading results in thalassaemic cardiomyopathy, leading to diastolic dysfunction and overt heart failure (HF). Serial electrocardiography (ECG), 2D-echocardiography (2DECHO) and cardiovascular magnetic resonance (CMR) help in early detection and risk stratification of ß-TM patients, to prevent complications, such as arrhythmias and sudden cardiac death. An established network of care between thalassaemia centres and local health providers is essential for optimal management.
Case presentation: We report 2 cases of HF in ß-TM of varied etiology, and different approaches undertaken for its early diagnosis and treatment.
Conclusion: It is important to differentiate various phenotypes of cardiomyopathy in ß-TM. Since, the management of each varies accordingly. ß-TM patients require a multi-disciplinary approach that includes HF specialists, haematologist, hepatologist, endocrinologist, psychologist, transfusion experts and nursing personnel to maximise benefits from the application of the modern HF therapeutic strategies in evaluation, monitoring and treatment.
SAHeart 2022;19:14-1
Toxicity to immune checkpoint inhibitors presenting as pulmonary arterial vasculopathy and rapidly progressing right ventricular dysfunction
Introduction: Immune Checkpoint Inhibitors (ICIs) are antitumor drugs associated with a number of serious immune-related adverse events (IRAEs). ICIs enhance anti-tumor immunity, thereby energized patient's immune system to fight cancer. IRAEs may affect functions of various organs, including heart, and may lead to morbidity and, to some extent mortality. Left ventricle (LV) myocarditis with dysfunction is a known side effect of this class of drugs. However, right ventricle (RV) myocarditis and pulmonary vasculitis are an unknown entity and has not been previously reported. Here, we present the first case of IRAEs causing selective RV involvement with dysfunctions, attributed to immune checkpoint inhibitors described till date in medical literature.Presentation of Case: A 58-year male presented with history of low-grade fever and weight loss. On palpation, he had diffuse cervical lymphadenopathy. Histopathology evaluation of lymph node revealed metastatic lesions of Renal Cell Carcinoma (RCC).Conclusion: Fatal cardiovascular adverse events can occur as a side effect of ICI. The combination of RV myocarditis with progressive pulmonary hypertension is fatal. Treatment with high dose corticosteroids and immunomodulators may help in patient survival. Physicians treating patients with ICIs should be aware of their lethal cardiotoxic side effects to reduce adverse cardiac outcomes. Because the number of patients exposed to this new immune therapy is expected to increase remarkably in the near future, our study encourages further work to define guidelines for cardiovascular monitoring and management
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Assessment and Recognition of MOOCs: The State of the Art
This study presents a descriptive overview of assessment and verification techniques used and emergent in contemporary online learning platforms. The Covid-19 pandemic has encouraged many institutions to move to online examinations at scale. Verification of learner identity is thus increasingly important for online education in examination and proctoring. Here we review state of the art approaches to ID verification, recognition, and assessment in Massive Open Online Courses (MOOC). Desktop research included research publications, grey literature, and direct interactions with MOOC platforms to identify current practices. The main focus was on public data from course pages on MOOC platforms, and particularly courses that had been grouped to offer a single academic program. Four approaches to verification of identity are described: basic identity checks; checks made by the university; external proctoring; and various types of interview. Our review demonstrates the absence of any universal approach. However, the emergent picture indicates increasing co-ordination across relevant stakeholders (including higher education institutions, employment services and the private sector). There remain significant challenges for online proctoring, including overcoming learner preferences and meeting the increased resourcing needed for human-led processes of identity verification. There remain significant ethical challenges regarding the use of learner data (especially biometrics). As a result, MOOC platforms may benefit from adopting identity verification strategies that are well-established in higher education institutions, such as plagiarism checking software and pedagogies like e-portfolios
Injectable gellan gum hydrogels with autologous cells for the treatment of rabbit articular cartilage defects
In this work, the ability of gellan gum hydrogels coupled with autologous cells to regenerate rabbit full-thickness articular
cartilage defects was tested. Five study groups were defined: (a) gellangumwith encapsulated chondrogenic predifferentiated rabbit adipose
stem cells (ASCþGF); (b) gellan gum with encapsulated nonchondrogenic predifferentiated rabbit adipose stem cells (ASC); (c) gellan gum
with encapsulated rabbit articular chondrocytes (AC) (standard control); (d) gellan gum alone (control); (e) empty defect (control). Fullthickness
articular cartilage defects were created and the gellangum constructs were injected and left for 8 weeks. The macroscopic aspect of
the explants showed a progressive increase of similarity with the lateral native cartilage, stable integration at the defect site, more
pronouncedly in the cell-loaded constructs. Tissue scoring showed that ASCþGF exhibited the best results regarding tissue quality
progression. Alcian blue retrieved similar results with a better outcome for the cell-loaded constructs. Regarding real-time PCR analyses,
ASCþGF had the best progression with an upregulation of collagen type II and aggrecan, and a downregulation of collagen type I. Gellan
gum hydrogels combined with autologous cells constitute a promising approach for the treatment of articular cartilage defects, and adipose
derived cellsmayconstitute a valid alternative to currently used articular chondrocytes.J. T. Oliveira acknowledge the Portuguese Foundation for Science and Technology (FCT) for his grant (SFRH/BD17135/2004). The authors thank the medical and technical staff of the Institute for Biomedical Sciences Abel Salazar (ICBAS) of the University of Porto, Portugal and the Institute for Health and Life Sciences (ICVS) of the University of Minho, Portugal. The authors also thank Dr. Patricia Malafaya, Cristina Correia, and Rui Pereira, for their help with the histological scoring. This work was carried out under the scope of the European NoE EXPERTISSUES, and partially supported by the European Project HIPPOCRATES
A hierarchical detection method in external communication for self-driving vehicles based on TDMA
Security is considered a major challenge for self-driving and semi self-driving vehicles. These vehicles depend heavily on communications to predict and sense their external environment used in their motion. They use a type of ad hoc network termed Vehicular ad hoc networks (VANETs). Unfortunately, VANETs are potentially exposed to many attacks on network and application level. This paper, proposes a new intrusion detection system to protect the communication system of self-driving cars; utilising a combination of hierarchical models based on clusters and log parameters. This security system is designed to detect Sybil and Wormhole attacks in highway usage scenarios. It is based on clusters, utilising Time Division Multiple Access (TDMA) to overcome some of the obstacles of VANETs such as high density, high mobility and bandwidth limitations in exchanging messages. This makes the security system more efficient, accurate and capable of real time detection and quick in identification of malicious behaviour in VANETs. In this scheme, each vehicle log calculates and stores different parameter values after receiving the cooperative awareness messages from nearby vehicles. The vehicles exchange their log data and determine the difference between the parameters, which is utilised to detect Sybil attacks and Wormhole attacks. In order to realize efficient and effective intrusion detection system, we use the well-known network simulator (ns-2) to verify the performance of the security system. Simulation results indicate that the security system can achieve high detection rates and effectively detect anomalies with low rate of false alarms
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