The Egyptian Cardiothoracic Surgeon (ECTS - E-Journal)
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Small signal model parameters analysis of GaN and GaAs based HEMTs over temperature for microwave applications
No full textThermal and small-signal model parameters analysis have been carried out on 0.5 μm × (2 × 100 μm) AlGaAs/GaAs HEMT grown on semi-insulating GaAs substrate and 0.25 μm × (2 × 100 μm) AlGaN/GaN HEMT grown on SiC substrate. Two different technologies are investigated in order to establish a detailed understanding of their capabilities in terms of frequency and temperature using on-wafer S-parameter measurement over the temperature range from −40 to 150 °C up to 50 GHz. The equivalent circuit parameters as well as their temperature-dependent behavior of the two technologies were analyzed and discussed for the first time. The principle elevation or degradation of transistor parameters with temperature demonstrates the great potential of GaN device for high frequency and high temperature applications. The result provides some valuable insights for future design optimizations of advanced GaN and a comparison of this with the GaAs technology
To Sign Up, or not to Sign Up?: Maximizing Citizen Science Contribution Rates through Optional Registration
No full textMany citizen science projects ask people to create an accountbefore they participate – some require it. What effect does theregistration process have on the number and quality of contri-butions? We present a controlled study comparing the effectsof mandatory registration with an interface that enables peo-ple to participate without registering, but allows them to signup to ‘claim’ contributions. We demonstrate that removingthe requirement to register increases the number of visitorsto the site contributing to the project by 62%, without reduc-ing data quality. We also discover that contribution rates arethe same for people who choose to register, and those whoremain anonymous, indicating that the interface should caterfor differences in participant motivation. The study providesevidence that to maximize contribution rates, projects shouldoffer the option to create an account, but the process shouldnot be a barrier to immediate contribution, nor should it berequired.<br/
Production of associated Y and open charm hadrons in pp collisions at s√=7 and 8 TeV via double parton scattering
No full textAssociated production of bottomonia and open charm hadrons in pp collisions at s√=7 and 8 TeV is observed using data corresponding to an integrated luminosity of 3 fb−1 accumulated with the LHCb detector. The observation of five combinations, Y(1S)D0, Y(2S)D0, Y(1S)D+, Y(2S)D+ and Y(1S)Ds+, is reported. Production crosssections are measured for Y(1S)D0 and Y(1S)D+ pairs in the forward region. The measured cross-sections and the differential distributions indicate the dominance of double parton scattering as the main production mechanism
Deprived Neighbourhoods in Transition: Divergent Pathways of Change in the Greater Manchester City-region
No full textMany studies of neighbourhood change adopt a ‘bookend’ mode of analysis in which a baseline year is identified for a chosen outcome variable from which the magnitude of change is calculated to a determined endpoint typically over bi-decadal or decadal timeframes. However, this mode of analysis smoothes away short-run change patterns and neighbourhood dynamics. The implications of this practice could be far reaching if it is accepted that as neighbourhoods change they are liable to cross a threshold and transition from one state to another in the short- as well as longer-term. In a case study of deprived neighbourhoods in the Greater Manchester city-region, this paper aims to contribute to neighbourhood change debates in two ways. The first is by isolating transition pathways for individual neighbourhoods using annual change data. The second is by testing the thesis that the more deprived a neighbourhood is, the more likely it is to respond with greater volatility to short-run shocks when compared with less-deprived neighbourhoods. Four indicators collected annually between 2001 and 2010 are used to develop a typology of neighbourhood change and a subsequent typology of neighbourhood transition. The analysis exposed 260 different transition pathways that deprived neighbourhoods followed over the study period. Multinomial logistic regression was then used to determine the odds of a neighbourhood undergoing transition along a specific pathway owing to its level of deprivation. The model revealed that the most deprived neighbourhoods were likely to follow more volatile transition pathways compared with the less-deprived neighbourhoods especially during periods of economic difficulty
A reflective journal as learning process and contribution to quality and validity in Interpretative Phenomenological Analysis
No full textUsing selected, contemporaneous illustrations from the reflective journal of a doctoral student undertaking data analysis for the first time, this article examines the relationship between journaling as a learning process when undertaking computer assisted qualitative data analysis and establishing quality and validity in Interpretative Phenomenological Analysis (IPA). The writing of the journal is shown both to enact some potential validity criteria (e.g. in producing an audit trail) whilst also recording and reflectively prompting the process of learning, interpretation and bracketing, thus evidencing transparency. By using a journal inside the software package and alongside the stages of the IPA, analysis within the software package, it is argued that quality and validity become dynamic, not static constructs. These constructs are intimately linked to the researcher-learning-process and permit a critical stance to be taken
Rising Power Clusters and the Challenges of Local and Global Standards
No full textThis paper explores the intersection between three processes associated with globalisation. First, the rise of emerging economies like China, Brazil and India, the so-called '˜Rising Powers'™, and their potential to define the contours of globalisation, global production arrangements and global governance in the 21st Century. Second, the importance of corporate social responsibility goals in the shaping of global trade rules and industrial practices, Third, the significance of small firm clusters as critical sites of industrial competitiveness. Some of the most significant examples of successful, innovative and internationally competitive small firm clusters from the developing world are located in the ˜'Rising Powers'™ and cluster promotion is a core element of national industrial policy in some of these countries. There is also evidence of engagement by clustered actors with CSR goals around labour, social, and environmental impacts. While these three processes have been separately studied there has been no attempt to explore their intersections. This paper addresses this gap through a comparative analysis of secondary data, and a detailed reading of the literature, on CSR and clusters in Brazil, China and India. It assesses the evidence on small firm clusters in the Rising Power economies and considers how these Rising Power clusters engage with CSR goals pertaining to labour, social and environmental standards. It argues for a greater focus on the formal and informal institutional context, termed the 'social contract', in explaining divergent experiences and practices observed across these countries. This raises important questions for future academic and policy research on clusters, CSR and the Rising Powers. The paper concludes by outlining a research agenda to explore the local and global consequences of the relationship between Rising Power clusters and international labour and social standards
The impact of fertilizer management on the oxidation status of terrestrial organic matter
No full textThe oxidative ratio (the ratio of moles of O2 produced per mole CO2 sequestered – OR) of the organic matter in the terrestrial biosphere governs the ability of the terrestrial biosphere to uptake CO2. The value of OR is known to vary between environments, but it would also be expected to vary with management. This study measured the OR of plant and soil samples from the long-term grassland plots on the Park Grass experiment at Rothamsted (SE England). The selected plots included those with different fertilizer inputs, including farmyard manure or inorganic fertilizers and an unfertilized control, each with and without lime. The measurements show that: (i) Use of inorganic fertilizer caused the OR of soil organic matter to increase. (ii) Farmyard manure (FYM) caused OR of the soil to increase but that of the vegetation decreased. (iii) Liming had the effect of decreasing OR and counteracting effects of fertilizer. (iv) The OR of the ecosystem increased with FYM application but decreased with inorganic fertilizer application. The global pattern in the use of organic amendments and inorganic fertilizers suggests that the likely impact of the predicted increase in global inorganic fertilizer use will result in a net decrease in the OR of the organic matter of the terrestrial biosphere, and an increase in its ability to act as a carbon sink. Corresponding increases in global FYM use and its impact upon global OR are unlikely to be large enough to counteract this effec
Multifunctionalized iron oxide nanoparticles for selective drug delivery to CD44-positive cancer cells.
No full textNanomedicine nowadays offers novel solutions in cancer therapy and diagnosis by introducing multimodal treatments and imaging tools in one single formulation. Nanoparticles acting as nanocarriers change the solubility, biodistribution and efficiency of therapeutic molecules, reducing their side effects. In order to successfully apply these novel therapeutic approaches, efforts are focused on the biological functionalization of the nanoparticles to improve the selectivity towards cancer cells. In this work, we present the synthesis and characterization of novel multifunctionalized iron oxide magnetic nanoparticles (MNPs) with antiCD44 antibody and gemcitabine derivatives, and their application for the selective treatment of CD44-positive cancer cells. The lymphocyte homing receptor CD44 is overexpressed in a large variety of cancer cells, but also in cancer stem cells (CSCs) and circulating tumor cells (CTCs). Therefore, targeting CD44-overexpressing cells is a challenging and promising anticancer strategy. Firstly, we demonstrate the targeting of antiCD44 functionalized MNPs to different CD44-positive cancer cell lines using a CD44-negative non-tumorigenic cell line as a control, and verify the specificity by ultrastructural characterization and downregulation of CD44 expression. Finally, we show the selective drug delivery potential of the MNPs by the killing of CD44-positive cancer cells using a CD44-negative non-tumorigenic cell line as a control. In conclusion, the proposed multifunctionalized MNPs represent an excellent biocompatible nanoplatform for selective CD44-positive cancer therapy in vitro