1,669 research outputs found

    Electrical transport and optical studies of ferromagnetic Cobalt doped ZnO nanoparticles exhibiting a metal-insulator transition

    Full text link
    The observed correlation of oxygen vacancies and room temperature ferromagnetic ordering in Co doped ZnO1-o nanoparticles reported earlier (Naeem et al Nanotechnology 17, 2675-2680) has been further explored by transport and optical measurements. In these particles room temperature ferromagnetic ordering had been observed to occur only after annealing in forming gas. In the current work the optical properties have been studied by diffuse reflection spectroscopy in the UV-Vis region and the band gap of the Co doped compositions has been found to decrease with Co addition. Reflections minima are observed at the energies characteristic of Co+2 d-d (tethrahedral symmetry) crystal field transitions, further establishing the presence of Co in substitutional sites. Electrical transport measurements on palletized samples of the nanoparticles show that the effect of a forming gas is to strongly decrease the resistivity with increasing Co concentration. For the air annealed and non-ferromagnetic samples the variation in the resistivity as a function of Co content are opposite to those observed in the particles prepared in forming gas. The ferromagnetic samples exhibit an apparent change from insulator to metal with increasing temperatures for T>380K and this change becomes more pronounced with increasing Co content. The magnetic and resistive behaviors are correlated by considering the model by Calderon et al [M. J. Calderon and S. D. Sarma, Annals of Physics 2007 (Accepted doi: 10.1016/j.aop.2007.01.010] where the ferromagnetism changes from being mediated by polarons in the low temperature insulating region to being mediated by the carriers released from the weakly bound states in the higher temperature metallic region.Comment: 7 pages, 6 figure

    A global mental health fund for serious mental illness in low-income and middle-income countries.

    Get PDF
    Serious Mental Illnesses (SMI) are psychiatric disorders (excluding developmental and substance use disorders) that result in considerable functional impairment. These conditions receive little or no funding in most Low and Middle Income (LAMI) countries. The huge gap in resources for SMI can only be met by a global fund to provide the treatment of SMI in LAMI countries. The Global Fund to fight AIDS established more than two decades ago, not only provided enormous funding but most importantly, generated the hope that the condition could be treated. We argue that SMI stand today where HIV-AIDS was a couple of decades ago. The cost effective interventions for these disorders are available. For example, it is estimated that that an extra 11 Naira or I$ 0.27 per capita would need to be invested each year to increase the present treatment coverage for schizophrenia of 20% to a level of 70% in Nigeria. The treatment package should include free access to essential medicines to treat psychotic disorders and a component of appropriate evidence based psychosocial intervention, which have been evaluated in number of studies in these countries. It is ethical and public health imperative that a Global Fund to provide the basic treatment for those suffering from SMI is established and the seed money for the proposed fund should be provided by rapidly developing LAMI countries such as India and South Africa

    Acute-on-chronic Liver Failure: MELD Score 30-day Mortality Predictability and Etiology in a Pakistani Population

    Full text link
    Background: Cirrhosis is a pathological condition that ultimately leads to liver failure. Acute on chronic liver failure (ACLF) has a high short term mortality rate. Viral hepatitis is the most common cause of liver failure in our local population. We carried out this study to identity the 30-day mortality and etiology of patients presenting with ACLF using Model for End-Stage Liver Disease (MELD) score predictability. Methodology: This was a descriptive case series, conducted at Sheikh Zayed Hospital, Lahore, Pakistan from January 31, 2018 to July 30, 2018. One hundred and eighty five patients who met the inclusion criteria were enrolled using 95% confidence level and 4% margin of error. Data was entered and analyzed with SPSS version 23.0. Numerical variables including age was presented by Mean ± S.D. Categorical variables i.e. gender, etiology of acute-on-chronic liver failure and 30-day mortality were presented by frequency and percentage. Data was stratified for age, gender, duration of chronic liver disease and MELD grade to address the effect modifiers. Post-stratification chi-square test was calculated using 95% significance (p≤0.05). Results: Majority of the enrolled patients were male (74.6%) while only 25.4% of the patients were female. One hundred and thirty patients (70.3%) had underlying viral hepatitis while twelve patients (6.5%) and forty three patients (23.2%) presented with alcoholic liver disease and drug-induced ACLF, respectively. Eighty patients (43.2%) died within 30 days of admission.The 30-day mortality with respect to MELD grade was statistically significant (p<0.001) with the highest mortality noted in grade-IV and thirty five patients (43.8%) dying within 30 days of admission (p<0.001). Grade-II and III MELD scores also contributed to the 30-day mortality with twenty three patients (28.8%) and nineteen patients (23.8%) dying within 30 days of admission (p<0.001). Conclusion: MELD scores are able to accurately predict the short-term mortality in patients with ACLF and viral hepatitis was the most common etiology in our population. Early detection and use of appropriate prognostic models may alleviate mortality and morbidity in paitents with ACLF

    Spontaneous recovery from depression in women: a qualitative study of vulnerabilities, strengths and resources

    Get PDF
    Objective: To gain insight into the perceived vulnerability and restitution factors for anxiety/or depression.Methods: Focus group discussion of seven married women recovered spontaneously from anxiety and/or depression, belonging to a lower middle class semi-urban community of Karachi.Results: Poverty, unemployment, abuse and on going difficulties were perceived as risk factors for depression. A reliable social support system, positive thinking approach, faith, prayers, and experiencing a turning point event were reported as factors that promoted recovery from anxiety and/or depression.CONCLUSION: Individual vulnerabilities, strengths and resources can have an important role in recovery from anxiety and/or depression in women

    The Effect of Fish Size and Condition on the Contents of Twelve Essential and Non Essential Elements in Aristichthys nobilis

    Get PDF
    The correlation coefficients between fish size (body weight and total length) and metal contents (Na, K, Ca, Mg, Mn, Fe, Cu, Zn, Cr, Co, Cd and Pb) in whole fish (Aristichthys nobilis) were determined. A total of 71 fish samples were collected from hatcheries and fish reservoirs located in Islamabad and Fatehjung. Highly significant (P<0.001) relationship between metal concentrations and fish size was found. Most of the metals (Na, K, Ca, Mg, Cu, Zn, Cr, Cd and Pb) showed an isometric increase, while Mn, Fe and Co showed an allometric increase in with increasing body weight. All metals showed isometric increase, while, Na, Mn, Fe, Cu, and Co showed positive allometric growth in relation to total length. The correlation coefficient (r) between different variables and wet body weight, condition factor was found highly significant (P<0.001) in examined fish except for Na, Ca, Cu, Zn, Cd and Pb while for total length the same results found except Ca, Cd, Zn and Pb. Variance inflation factor values of regression coefficients in multiple regression analysis for each variable were lesser than 10. The metal levels of the examined fish were lower than the recommended values in fish and fishery products set by FAO

    A hybrid approach to recognising activities of daily living from object use in the home environment

    Get PDF
    Accurate recognition of Activities of Daily Living (ADL) plays an important role in providing assistance and support to the elderly and cognitively impaired. Current knowledge-driven and ontology-based techniques model object concepts from assumptions and everyday common knowledge of object use for routine activities. Modelling activities from such information can lead to incorrect recognition of particular routine activities resulting in possible failure to detect abnormal activity trends. In cases where such prior knowledge are not available, such techniques become virtually unemployable. A significant step in the recognition of activities is the accurate discovery of the object usage for specific routine activities. This paper presents a hybrid framework for automatic consumption of sensor data and associating object usage to routine activities using Latent Dirichlet Allocation (LDA) topic modelling. This process enables the recognition of simple activities of daily living from object usage and interactions in the home environment. The evaluation of the proposed framework on the Kasteren and Ordonez datasets show that it yields better results compared to existing techniques

    Maximizing the economic benefits of a grid-tied microgrid using solar-wind complementarity

    Get PDF
    The increasing use of intermittent, renewable energy sources (RESs) for electricity generation in microgrids (MGs) requires efficient strategies for reliable and economic operation. Complementarity between RESs provides good prospects for integrating several local energy sources and reducing the costs of MG setup and operations. This paper presents a framework for maximizing the economic benefits of a grid-tied MG by exploiting the spatial and temporal complementarity between solar and wind energies (solar-wind complementarity). The proposed framework considers the cost of energy production from different RESs and the cost of bi-directional energy exchange with the main grid. For a given RES mix, a minimum system power loss (SPL) threshold can also be determined. However, at this SPL threshold, MG energy exchange cost is not always minimized. The framework determines the optimized SPL value (above the threshold) at which MG energy exchange cost gets minimized. Through this framework, MG operator can decide appropriate RES mix and can achieve various tradeoffs according to the energy production cost, solar-wind complementarity of the site and its required economic objectives

    Improving Student Engagement and Performance in Computing Final Year Projects

    Get PDF
    There has been a seismic shift in the UK higher education landscape during the last decade. This has been driven by the formation of the Office for Students (OfS) and the introduction of the Teaching Excellence Framework (TEF), where the emphasis has been on programmes offering students higher value when it comes to employability, retention and overall student experience. One of the critical challenges that impact student experience is being able to enhance student engagementwithin a learning environment. Final year individual projects, which are generally unstructured in nature, is a significant contributor to programmes of study, yet remains an area where this problem is exacerbated. In an attempt to address this issue, our earlier work lays the foundation for a teaching & learning framework covering computing final year projects. In this paper, we present an extension to the framework and its implementation in 2016/17 following its first trial run within a Computer Science department at a UK university in 2015/16. We discuss the two implementations in practice and provide operational guidance. A large-scale longitudinal empirical study considering the performance of 625 final year undergraduate students over a period of five years is presented to ascertain the effectiveness of the framework. The study finds a consistent and significant positive impact on both student performance and engagement as a result of the original framework and further gains from the enhancements

    An Effective Framework for Enhancing Student Engagement and Performance in Final Year Projects

    Get PDF
    Over the years, there have been many factors that have influenced the landscape of higher education within the UK. These factors include the rise in tuition fees, the introduction of the Teaching Excellence Framework (TEF) and the formation of Office for Students. Although student performance plays a vital part, another significantly influential key performance indicator that impacts these factors is student experience, which is influenced by positive or negative feedback and engagement. Despite student engagement forming a key part of the learning environment, it is still perceived as one of the weakest aspects when it comes to enhancing the student experience. In this paper, we present the implementation of an innovative, holistic teaching & learning framework for the final year project module trialed within the Department of Engineering and Computing at the University of East London. This project module had been running in different forms since the inception of the undergraduate programmes within the department, however it generally yielded poor and inconsistent evaluation, student experience and engagement. The framework was introduced during the academic year 2015/16, where its evaluation has shown a positive impact on student engagement, performance and experience, compared to the previous year

    Enhancing Student Learning, Engagement, and Employment Through Inclusive Curriculum Design

    Get PDF
    The diverse student body at Queen Mary University of London requires an effective approach to ensure equal opportunity in higher education. This includes promoting equality, inclusion, equity, and access to services. To address this, the authors present a case study about a redesigned cloud computing module to enhance student engagement, employability, and intercultural learning. The module's learning outcomes are based on the students' graduate attributes and cross-disciplinary abilities, as defined by professional frameworks. To support equal opportunity and facilitate multicultural growth, they have updated the education and learning model to include innovative teaching methods and materials for efficient curriculum delivery. This study establishes the foundation for an action research review of cloud computing that aims to create an inclusive curriculum
    • …
    corecore