2,428 research outputs found
From welfare to correction: a review of changing discourses of secure accommodation
Any group care centre has in various ways to incorporate aspects of treatment, teaching, nurturance and control according to the specific needs of the children referred there. Yet experience has shown that the ethos of most group care centres is heavily dominated by the single yet simplistic purpose that underpins the resource system sponsoring a centre. This often results in the overall developmental needs of children being overwhelmed by a single purpose, which although important is an incomplete response at best
Quantum dot emission from site-controlled ngan/gan micropyramid arrays
InxGa1−xN quantum dots have been fabricated by the selective growth of GaN micropyramid arrays topped with InGaN/GaN quantum wells. The spatially, spectrally, and time-resolved emission properties of these structures were measured using cathodoluminescence hyperspectral imaging and low-temperature microphotoluminescence spectroscopy. The presence of InGaN quantum dots was confirmed directly by the observation of sharp peaks in the emission spectrum at the pyramid apices. These luminescence peaks exhibit decay lifetimes of approximately 0.5 ns, with linewidths down to 650 me
Universal screening for meticillin-resistant Staphylococcus aureus : interim results from the NHS Scotland pathfinder project
Following recommendations from a Health Technology Assessment (HTA), a prospective cohort study of meticillin-resistant Staphylococcus aureus (MRSA) screening of all admissions (N = 29 690) to six acute hospitals in three regions in Scotland indicated that 7.5% of patientswere colonised on admission to hospital. Factors associated with colonisation included re-admission, specialty of admission (highest in nephrology, care of the elderly, dermatology and vascular surgery), increasing age, and the source of admission (care home or other hospital). Three percent of all those who were identified as colonised developed hospital-associated MRSA infection, compared with only 0.1% of those not colonised. Specialtieswith a high rate of colonisation on admission also had higher rates of MRSA infection. Very few patients refused screening (11 patients, 0.03%) or had treatment deferred (14 patients, 0.05%). Several organisational issues were identified, including difficulties in achieving complete uptake of screening (88%) or decolonisation (41%); the latter was largely due to short duration of stay and turnaround time for test results. Patient movement resulted in a decision to decontaminate all positive patients rather than just those in high risk specialties as proposed by the HTA. Issues also included a lack of isolation facilities to manage patients with MRSA. The study raises significant concerns about the contribution of decolonisation to reducing risks in hospital due to short duration of stay, and reinforces the central role of infection control precautions. Further study is required before the HTA model can be re-run and conclusions redrawn on the cost and clinical effectiveness of universal MRSA screening
Towards an ecological network for the Carpathians
The Carpathian Biodiversity Information System (CBIS) and the proposal for an ecological network for the eastern part of the Carpathians are the two main outcomes of the project funded by the BBI Matra program of the Dutch government. This brochure presents information on how the CBIS was designed, and how the data stored can be retrieved and used. It also clarifies how the CBIS data were used to design the ecological network and, last but not least, it offers recommendations for the use of the proposed ecological network in supporting sustainable developmentin the Carpathians. Due to funding restrictions, the project focused on three east Carpathian countries: Romania, Serbia and Ukraine, which together host the largest area of the Carpathians (Fig. 2). Geographically, the Eastern Carpathians also include parts of the Carpathians located in Poland and Slovakia. Data collection in the Western Carpathians (Czech Republic, Poland, Slovakia and Hungary) will be completed by 2010 and is funded by a parallel project
Calculations of liquid helium and neon VUV emission spectra, self-absorption and scattering for a neutrino detector
To evaluate the feasibility of the recently proposed detection scheme of low
energy neutrinos released from the Sun and supernovae called CLEAN, Cryogenic
Low Energy Astrophysics with Noble Gases, which relies on the transparency of
noble-gas cryogenic liquids to VUV radiation produced by neutrinos, we analyze
theoretically VUV emission, self-absorption, and scattering of liquid helium
and neon, primary candidates for CLEAN. Owing to strong repulsion of noble-gas
atoms in the ground states at the equilibrium distance of the relevant excited
state, the emission spectrum is substantially shifted from the absorption
spectrum, and in principle the absorption is expected very small, allowing
building large detectors. Our analysis, however, shows that the self-absorption
and Rayleigh scattering are comparable to the size of the proposed detector.
Our theoretical emission spectra are found in agreement with experimental
observations although some deviation exists due to binary-interaction
approximation, and our ab initio Rayleigh scattering lengths are found in
agreement with other calculations based on the extrapolation of experimental
refraction indices. The absorption process can result in either re-emission,
which conserves the number of photons but delays their escape from the liquid,
or in non-radiative quenching
Initial distribution spread: A density forecasting approach
Ensemble forecasting of nonlinear systems involves the use of a model to run forward a discrete ensemble (or set) of initial states. Data assimilation techniques tend to focus on estimating the true state of the system, even though model error limits the value of such efforts. This paper argues for choosing the initial ensemble in order to optimise forecasting performance rather than estimate the true state of the system. Density forecasting and choosing the initial ensemble are treated as one problem. Forecasting performance can be quantified by some scoring rule. In the case of the logarithmic scoring rule, theoretical arguments and empirical results are presented. It turns out that, if the underlying noise dominates model error, we can diagnose the noise spread
Evaluation of some important physicochemical properties of starch free grewia gum
Gums obtained by extraction from the inner bark of stems can be found in association with starch, which must be digested in order to obtain a refined polysaccharide isolate. In the present study, grewia gum obtained from the inner bark of the stems of Grewia mollis was shown to co-exist with starch and the effect of starch digestion on the physicochemical properties of the resultant polysaccharide was evaluated.
The gum was extracted by maceration of the inner bark in deionized water and isolated by a combination of filtration, centrifugation and finally precipitation with absolute ethanol to produce the crude grewia gum extract (GG). The presence and content of starch in the gum sample was determined followed by enzymatic digestion of the starch using α-amylase (Termamyl 120L) to give a starch-free extract (GGDS). Physicochemical properties of the extracts such as total carbohydrates, total protein, differential sugar composition, NMR, intrinsic viscosity and rheological behaviour of the samples were evaluated.
The GG extract had total carbohydrate content of ∼ 60 % out of which 11.8 % was starch, and a protein content of 2.3 %. Samples also contained galacturonic and glucuronic acid which were highly acetylated. Both samples had a higher proportion of galacturonic acid than glucuronic acid and contained rhamnose, arabinose, galactose, glucose and xylose as neutral sugars in varying proportions. Rheological measurements on 2 %w/w dispersions of the extracts show minor differences between both the original extract and the de-starched material but were influenced by changes in pH
A chemical element sustainability index
As product development becomes increasingly complex, the demand for the earth's mineral ores increases and with it, the challenge to achieve global “sustainability”. Chemical elements are the building blocks of natural resources which are sourced from across the planet to manufacture globally traded goods. While global technological, social and economic progress accelerates, evaluating the sustainability of these building blocks remains a challenge. Numerous methodologies to evaluate sustainability exist but most rely on high levels of data collection. In this paper, a methodology is presented within a multi-criteria decision analysis and composite indicator framework with the aim of rapidly and comprehensively estimating the sustainability of a chemical element . The framework is based on triple bottom line principles; the environment, economy and society, to measure the sustainability of 59 chemical elements. The output, the chemical element sustainability index (CESI), is a single value supported by the aggregation of the Human Development Index, Global Warming Potential, and National Economic Importance indicators, derived through a rigorous and systematic selection process. Recycling rate is employed within the framework as a control variable given its importance as a sustainability strategy. The results show that the greater the Human Development Index, National Economic Importance and Recycling Rate, and the lower the Global Warming Potential, the more sustainable the chemical element is, and vice-versa. The CESI was validated using three representative piezoelectric materials as a case study. The framework presented is useful for product designers, policy makers and educational bodies, to support decision making towards sustainable production and consumption
Life cycle assessment and environmental profile evaluations of high volumetric efficiency capacitors
High volumetric efficiency capacitors are found in all smart electronic devices, providing important applications within circuits, including flexible filter options, power storage and sensing, decoupling and circuit smoothing functions. Multilayer ceramic capacitors (MLCCs) hold the major market share but tantalum electrolytic capacitors (TECs) provide a viable alternative if higher breakdown strengths are required. The reduced costs, smaller dimensions suitable for space-constrained electronic circuits, exceptional high-frequency characteristics, higher reliability, ripple control and longevity, however, are driving the market to replace TECs with MLCCs wherever possible. To date, no current research regarding the transition from TECS to MLCCs has been conducted from an entirely environmental viewpoint. This article identifies, quantifies, ranks and compares the environmental impacts of the MLCC and TEC supply chains using an integrated hybrid life cycle assessment framework. Three recovery methods: incineration; hydrometallurgy and pyrometallurgy are considered in the overall impact assessment. Electrical energy consumption during fabrication alongside the use of nickel paste are the major environmental hotspot for MLCCs. The high proportion of tantalum in TECs results in an overall greater environmental impact in comparison with MLCCs, due to intensive extraction, processing and purification requirements of tantalum. Of the three recovery methods, the hydrometallurgy process offers the least environmental impact for both MLCCs and TECs. Overall, the current work shows that while the industry led transition from TECs to MLCCs offers both an operational and functional edge, it is also an environmentally intelligent move. Intervention options that can further drive down the environmental impacts of MLCCs are also proposed such as a reduction in the reliance of MLCCs on rare earth elements and Cu external electrodes in some designs and material recovery
Chemostratigraphy of Neoproterozoic carbonates: implications for 'blind dating'
The delta C-13(carb) and Sr-87/Sr-86 secular variations in Neoproteozoic seawater have been used for the purpose of 'isotope stratigraphy' but there are a number of problems that can preclude its routine use. In particular, it cannot be used with confidence for 'blind dating'. The compilation of isotopic data on carbonate rocks reveals a high level of inconsistency between various carbon isotope age curves constructed for Neoproteozoic seawater, caused by a relatively high frequency of both global and local delta C-13(carb) fluctuations combined with few reliable age determinations. Further complication is caused by the unresolved problem as to whether two or four glaciations, and associated negative delta C-13(carb) excursions, can be reliably documented. Carbon isotope stratigraphy cannot be used alone for geological correlation and 'blind dating'. Strontium isotope stratigraphy is a more reliable and precise tool for stratigraphic correlations and indirect age determinations. Combining strontium and carbon isotope stratigraphy, several discrete ages within the 590-544 Myr interval, and two age-groups at 660-610 and 740-690 Myr can be resolved
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