Coping with carbon: a near-term strategy to limit carbon dioxide emissions from power stations

Burning coal to generate electricity is one of the key sources of atmospheric carbon dioxide emissions; so, targeting coal-fired power plants offers one of the easiest ways of reducing global carbon emissions. Given that the world's largest economies all rely heavily on coal for electricity production, eliminating coal combustion is not an option. Indeed, coal consumption is likely to increase over the next 20-30 years. However, the introduction of more efficient steam cycles will improve the emission performance of these plants over the short term. To achieve a reduction in carbon emissions from coal-fired plant, however, it will be necessary to develop and introduce carbon capture and sequestration technologies. Given adequate investment, these technologies should be capable of commercial development by ca 2020.     

Outcome after urgent surgery for grade IV subarachnoid hemorrhage

BACKGROUND: Outcome after subarachnoid hemorrhage (SAH) in patients presenting with poor clinical grade has historically been dismal. As a result, many poor-grade patients have been excluded from early, aggressive surgery. We present a consecutive series of 27 patients with acute (less than 24 h since clinical onset) Grade IV SAH treated with early surgery. METHODS: All patients were treated with immediate ventricular drainage, rigid hemodynamic control, early angiography and surgery within 24 h of presentation. Patients were followed for a minimum of 6 months and their outcomes categorized using a four-tiered scale: 1) independent and working, 2) impaired but independent, 3) severely impaired and dependent, and 4) dead. RESULTS: Seven patients died within 48 h of admission. The remaining 20 patients survived to discharge. At the time of discharge eight of these patients were considered to be impaired but independent and twelve were considered severely impaired and dependent. At follow-up, seven patients were independent and working, six were impaired but independent, five were severely impaired and dependent, and two severely impaired patients had subsequently died. CONCLUSIONS: We conclude that urgent surgery for poor-grade SAH can produce quality survival for a higher percentage of patients than is historically reported with delayed surgery.     

Piezoelectrically tuned dielectric resonators

A simple technique for rapid tuning of a dielectric resonator using piezoelectric actuation is described. Results are presented for three dielectric resonator materials with relative permittivities of 9.5, 47 and 100 and dielectric Q-factors of 50000 (10 GHz), 9000 (5 GHz) and 16000 (3 GHz). The advantage of the proposed tuning method is that little degradation in the device Q-factor is observed even with tuning up to 2%     

Struggling for control: the care experiences of 'difficult' patients in mental health services

Although there is increasing recognition of the existence of 'difficult' patients who present particular challenges to mental health nurses, no research has been conducted into their perceptions of services and their experiences of care. This study identifies mental health service users who are defined by nurses as 'difficult' and explores their perceptions of their care experience. The results support earlier studies which suggested that 'difficult' patients challenge nurses' competence and control: despite their different roles both nurses and 'difficult' patients were aware of the struggle to gain or retain a notion of control. Respondents were able to identify the qualities of nurses and nursing interventions which had a positive effect on their care experience. Where nurses were perceived to demonstrate respect, time, skilled care and a willingness to give patients some control and choice in their own care, feelings of anger were reduced. These findings are discussed within the conceptual framework of 'power over' and 'power to' and implications for practice and research are considered.     

Analysis of Vitamin K1 in Soybean Seed: Assessing Levels in a Lineage Representing Over 35 Years of Breeding

Recommendations by the Organization of Economic Cooperation and Development (OECD) for compositional assessments of new genetically modified (GM) soybean now include measurement of vitamin K₁. Here we employ an HPLC method to provide information on variation in levels of vitamin K₁ in seed from soybean representing over 35 years of breeding. Vitamin K₁ analysis was conducted on seed from six conventional lines and three GM glyphosate‐tolerant lines grown concurrently at two sites in the US. Vitamin K₁ levels in seed were influenced by both location and germplasm. Levels were higher in the newer higher‐yielding lines when compared with the older varieties. The effect of GM was negligible. Overall, our study showed, using a method suitable for compositional assessments under OECD guidelines, that (i) variation in levels of vitamin K₁ in soybean is associated with a safe history of consumption and (ii) that modern breeding strategies can be employed for soybean varietal development without adversely impacting vitamin K₁ levels.     

Measurements of Permittivity, Dielectric Loss Tangent, and Resistivity of Float-Zone Silicon at Microwave Frequencies

The complex permittivity and resistivity of float-zone high-resistivity silicon were measured at microwave frequencies for temperatures from 10 up to 400 K employing dielectric-resonator and composite dielectric-resonator techniques. At temperatures below 25 K, where all free carriers are frozen out, loss-tangent values of the order of 2times10^-4 were measured, suggesting the existence of hopping conductivity or surface charge carrier conductivity in this temperature range. Use of a composite dielectric-resonator technique enabled the measurement of materials having higher dielectric losses (or lower resistivities) with respect to the dielectric-resonator technique. The real part of permittivity of silicon proved to be frequency independent. Dielectric losses of high-resistivity silicon at microwave frequencies are mainly associated with conductivity and their behavior versus temperature can be satisfactory described by dc conductivity models, except at very low temperatures     

Transforming teaching and learning: embedding ICT into everyday classroom practices

Drawing on socio‐cultural theory, this paper describes how teams of teachers and researchers have developed ways of embedding information and communications technology (ICT) into everyday classroom practices to enhance learning. The focus is on teaching and learning across a range of subjects: English, history, geography, mathematics, modern foreign languages, music and science. The influence of young people's out‐of‐school uses of ICT on in‐school learning is discussed. The creative tension between idiosyncratic and institutional knowledge construction is emphasised and we argue that this is exacerbated by the use of ICT in the classroom.     

Molecular conductors and semiconductors—the electronic materials of the future?

The range of materials used by the electronics industry is very limited. Conductors are invariably metals such as copper or aluminium, while silicon, gallium arsenide and their close relatives provide the semiconductors. If research in progress today bears fruit the picture in the future could look very different. Scientists are studying an exciting class of materials called molecular conductors. Polymeric semiconductors that can be moulded into shape and processed at low temperatures, organic metals and room temperature superconductors are some of the possibilities now being discussed.     

Thrombosis of the cranial vena cava in a cow

Thrombosis of the cranial vena cava in a cow was followed by the formation of aneurysms in the pulmonary arteries. Embolism, pulmonary hypertension and the development of a collateral venous and lymphatic circulation are the suggested causes of these uncommon arterial lesions.