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Metastable effects in silicon thin films:atmospheric adsorption and light-induced degradation
No full textThe effects of exposure to atmosphere (ageing) and light-soaking on coplanar dark- and photo-conductivity of silicon films of varying crystallinity are examined. Dark conductivity generally increases on ageing in films with significant amorphous fraction and decreases in largely crystalline films, and may be reversed by annealing under vacuum at 130 °C consistent with adsorption and desorption of atmospheric components. Thinner films are more strongly affected by ageing. Boron doping appears to compensate charge introduced by ageing, though there are disagreements in detail. In comparison with ageing, moderate light-soaking affects dark conductivity in transitional microcrystalline silicon films only slightly. Both processes change the majority carrier mu–tau product in line with shifts in Fermi level position
Effect of spironolactone on physical performance in older people with self-reported physical disability
No full textBackgroundInterventions that improve muscle function may slow decline in physical function and disability in later life. Recent evidence suggests that inhibition of the renin-angiotensin-aldosterone system may maintain muscle function. We evaluated the effect of aldosterone blockade on physical performance in functionally impaired older people without heart failure.MethodsIn this parallel-group, double-blind, randomized, placebo-controlled trial, community-dwelling participants aged =65 years with self-reported problems with activities of daily living were randomized to receive 25 mg spironolactone or identical placebo daily for 20 weeks. The primary outcome was change in 6-minute walking distance over 20 weeks. Secondary outcomes were changes in Timed Up and Go test, Incremental Shuttle Walk Test, Functional Limitation Profile, EuroQol EQ-5D, and Hospital Anxiety and Depression Scale over 20 weeks.ResultsParticipants’ mean (standard deviation) age was 75 (6) years. Of the 93% of participants (112/120) who completed the study, 106 remained on medication at 20 weeks. There was no significant difference in change in 6-minute walking distance at 20 weeks between the spironolactone and placebo groups (mean change, -3.2 m; 95% confidence interval, -28.9 to 22.5; P = .81). Quality of life improved significantly at 20 weeks, with an increase in EuroQol EQ-5D score of 0.10 (95% confidence interval, 0.03-0.18; P < .01) in the spironolactone group relative to the placebo group. There were no significant differences in between-group change for other secondary outcomes.ConclusionsSpironolactone was well tolerated but did not improve physical function in older people without heart failure. Quality of life improved significantly, and the possible mechanisms for this require further study
The effects of sustained forest use on hillslope soil hydraulic conductivity in the Middle Mountains of Central Nepal
No full textThis work investigated the multi-decadal changes in field saturated hydraulic conductivity, Kfs, beneath severely degraded pasture, natural forest and two mature planted Pinus roxburghii stands between two sets of measurements made in 1986 and 2011 at the same locations in the Middle Mountains of Central Nepal.Multiple measurements of Kfs were made at the four sites, both at the surface and at depths of 005–015, 015–025 and 025–050 m. The Kfs results were subsequently combined with rainfall intensities associated with different time intervals to infer multi-decadal changes in dominant hillslope stormflow pathways. The widely assumed hydrological benefits of reforesting degraded land through the enhancement of near-surface permeability due to such factors as the incorporation of a greater amount of organic matter, formation of macropores, as well as root development were not observed in this study. Continued heavy use of the natural and planted forests of the Middle Mountains, particularly the removal of understory vegetation and leaf litter, and cattle grazing, are considered to be the chief causal factors of the presently observed deterioration in forest hydrological functioning. This situation is typical not only of the Middle Mountain Zone across the Himalaya but is also observed in other densely populated parts of South and South-East Asia. The key conclusion of this work is that simply planting trees in degraded landscapes is not sufficient in itself to restore watershed hydrological functioning. Attention also needs to be given to on-going management of the reforested areas to balance product usage with watershed functions.</p
Perceptions and practices of social behaviors among university students in Pakistan
No full textThe major purpose of the article was to identify the perceptions and practices of social behaviorsamong university students in Pakistan. More than 350 students, 50 teachers and 45 parents of thestudents from 2 universities responded on the three independent questionnaires, one each forstudents, teachers and parents, through scheduled meetings. Some common behaviors were alsoobserved at canteen, grounds, university transport and corridors etc through observation sheet.SPSS and NVIVO software were employed to analyze quantitative and qualitative data sets.Sportsmanship, Substance misuse, cheating, wreckage, joyriding, bullying, harassment,pressurizing others, aggression, love affairs, classroom disturbance, graffiti writing andprostitution were appeared as the most commonly occurring negative behaviors among thestudents. Recommendations were made to modify the negative behaviors among students
Prototype energy autonomous studio in Dundee, Scotland
No full textPrototype Energy Autonomous Studio’ is a net-zero energy, PV- and wind-powered configurable off-grid demonstrator building, located in Dundee University’s Botanical Gardens. It was developed and constructed as a self-build collaborative student project, led by the Department of Architecture’s Macro Micro Master of Architecture research unit, with contributions from masters’ students in Civil Engineering, Renewable Energy and Applied Computing. A consortium of some 50 manufacturers and suppliers contributed specialist knowhow and donations of in-kind materials. The prototype represents a ‘live’ test-bed, monitoring energy generation and storage technologies and performance of the Passivhaus timber frame construction. This enables the feasibility of ultra-low energy and off-grid buildings powered solely by renewable sources to be assessed in the context of the Scottish Government’s strategy for a low-carbon future. We describe the research rationale, the processes and decision-making in the development of the formal and technical design of the building and energy generation, monitoring and management systems, and review present status and future expectations
Z-scan measurements of the nonlinear refractive index of a pumped semiconductor disk laser gain medium
No full textWe measure the nonlinear refractive index of an antiresonant 1050 nm semiconductor disk laser (SDL) gain medium using a reflection-type z-scan system, with a 1064 nm, 10-ps-pulse laser as a probe, and a fiber-coupled 808 nm diode pump laser for carrier injection. Empirically, the nonlinear refractive index is found to depend approximately linearly on applied pump intensity, having a value of −1.5(0.2) × 10−12 cm2/W at zero excitation but increasing to take on positive values at typical SDL operating conditions. The focal lengths of corresponding Kerr lenses calculated using typical SDL pulse intensities and spot sizes are sufficiently short to be comparable to SDL cavity mirrors, implying that Kerr lens modelocking may be responsible for the behavior described in recent reports of self-mode-locked SDLs
The design of children’s outdoor activities:sustainability and early learning experiences
No full textThere is little doubt that the objects and daily patterns of children’s play are changing, often to the detriment of outdoor activities. This occurs at a time when we need more understanding and appreciation of the natural world in order to live sustainably. It is now widely acknowledged that outdoor education contributes significantly to children’s physical and mental health as well as enabling them to develop as successful learners, confident individuals, responsible citizens and effective contributors to society whilst also enhancing environmental awareness (Scottish Executive, 2004).This research project is at the interface of children’s play, learning, nature and sustainability. It is one of a portfolio of design research projects (MPhil and PhD) being conducted by The Centre for the Study of Natural Design at the University of Dundee and Scottish Outdoor Education Centres (SOEC). This paper describes ‘a day in a life’ of children at one site operated by SOEC with a view to understanding the relationships and patterns of child’s play. Based on early findings, the authors reflect on what needs to be done next before moving towards designing and developing a range of outdoor learning activities. The paper concludes with a discussion on the choice of research methods which might prove useful in exploring these active situations in a more holistic manne
The event(s) of process
No full textThere are two main readings of the term ‘event’ shaping contemporary philosophy. In the continental tradition the term usually refers to an emergence of meaning and a disruption of a given conceptual order. In this use ‘event’ is related to hierarchies, orders and structures of meaning; it is concerned with processes of meaning-making and I thus take it to be metaphysical in nature. In the analytic tradition, ‘events’ (plural) belong to the realm of category theory or ontology. They are ontological entities, bound processes or processual entities with a definite beginning and end. These events are particular, individual, ‘countable entities’ that are fundamentally temporal. What both traditions share in approaching the event/events is the insight that change, becoming, and movement are fundamental phenomena characterising our world, as well as the conviction that these phenomena need to be adequately accounted for. In what follows I will show how both analytic-ontological and continental-metaphysical approaches to event(s) can be fruitfully combined and embedded within a broadly dynamic understanding of reality, namely in an understanding of reality as process, where ‘process’ describes a general dynamicity denoting any kind of genuine movement that does not rest on or presuppose an unchanging basis
Extracellular Matrix (ECM) Mimicking Hybrid and Composite Nanofiber Materials: A General Perspective on Structural and Chemical Biomimicry and Their Role in Wound Healing and Skin Modelling
No full textThe main purpose of implementing biomaterials for regenerative medicine, e.g., in wound healing, is provision of topographical, biochemical, and biomechanical cues to regulate cell activities and to support cell attachment. In this regard, nature has already established a template, i.e., the extracellular matrix (ECM), which has been inspiring in the creation of different classes of biomaterials. Biomaterials that recapitulate the structure, composition, and dynamics of the ECM have been shown to be effective in tissue regeneration and wound healing applications. In particular, nanofiber materials that can simulate the ECM’s collagen nanofilamentous structure, in terms of topography and biochemistry, are highly attractive not only for regeneration of wounded tissue but also for modelling of human native skin to study disease, aging, and therapeutic conditions. Hybrid or composite nanofibers made of synthetic materials, natural materials or a blend of both can not only be employed as wound healing materials, but also as the basis of the epidermal and dermal layer in three-dimensional (3D) organotypic skin models, a new paradigm for modelling of human skin to identify the efficacy of therapeutics and wound healing processes. In this chapter, hybrid and composite nanofibrous materials are discussed from an ECM biomimicry standpoint (structural and biochemical biomimicry) that is crucial for their wound healing and skin modelling application. In collecting the presented information, we mainly considered the innovations carried out in the past five years to provide an updated overview on the ECM mimicking nanofibrous materials that have been applied as wound dressings, skin substitutes, and 3D skin models
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