695915 research outputs found
Sort by
Probabilistic Multi-Stability Assessment in Power Systems with Uncertain Wind Generation
No full textThis paper presents the application of aprobabilistic multi-stability assessment of a modified two-areasystem under the presence of low and high uncertainty sources.The stability of the network is assessed under four stabilityregimes: frequency, small-signal rotor angle, large-signal rotorangle, and long-term voltage. The probabilistic assessment iscarried out using Monte Carlo simulation. Two casesconsidering low and high uncertainty are investigated. Theobtained results are presented in the form of parallel coordinateplots so that the interaction between multiple stability regimescan be more easily understood. It is observed that the poorresponse of small-signal rotor angle stability generallycorresponds to poor response of other stability types in lowuncertainty case. However, once the level of uncertaintyincreases and more sources of uncertainty exist, thisrelationship is significantly changed
Reformulating the Relationship between Cognitive Analytic Therapy (CAT) and Research: Navigating the Landscape and Exploring New Directions
No full textCognitive Analytic Therapy (CAT) is an integrative therapy that is increasingly being used with a wide range of difficulties. Following the clinical interest in this approach, research into CAT has increased in recent years. In this editorial we outline the current landscape of research into CAT, noting the emphasis on smaller-scale, practice-based research, as well as growing body of larger trials into CAT. Next we consider how CAT may strengthen its relationship with research and develop the evidence base for this approach further. We consider the importance of collaboration, and the value of holding onto the core principles and features of CAT. We outline the need to balance innovation against established methods of evaluating treatments for mental health difficulties. We refer to relevant studies published in this special issue of Psychology & Psychotherapy
Thermodynamic Analysis of Steam Reforming of Glycerol (SRG) for Hydrogen Production at Atmospheric Pressure
No full textThermodynamic chemical equilibrium analysis of steam reforming of glycerol (SRG) for selective hydrogen production was performed based on the Gibbs free energy minimisation method. The ideal SRG reaction (C3H8O3 + 3 H2O 3 CO2 + 7 H2) and a comprehensive set of side reactions during SRG are considered for the formation of a wide range of products. Specifically, this work focused on the analysis of formation of H2, CO2, CO and CH4 in the gas phase and determination of the carbon free region in SRG under the conditions at atmospheric pressure, 600–1,100 K and 1–10 atm with the steam-to-glycerol feed ratios (SGFR) of 1:5–10. The reaction conditions which favoured SRG for H2 production with minimum coke formation were identifies as: atmospheric pressure, temperatures of 900–1,050 K and SGFR of 10:1. The influence of using the inert carrier gas (i.e. N2,) in SRG was studied as well at atmospheric pressure. Although the presence of N2 in the stream decreased the partial pressure of reactants, it was beneficial to improve the equilibrium yield of H2. Under both conditions of SRG (with/without inert gas), the CH4 production is minimised, and carbon formation was thermodynamically unfavoured at steam rich conditions of SGFR >5:1
An Improved Gravitational Search Algorithm to the Hybrid Flowshop with Unrelated Parallel Machines Scheduling Problem
No full textThe hybrid flowshop scheduling problem with unrelated parallel machines exists in many industrial manufacturers, which is an NP-hard combinatorial optimization problem. To solve this problem more effectively, an improved gravitational search (IGS) algorithm is proposed which combines three strategies: generate new individuals using the mutation strategy of the standard differential evolution (DE) algorithm and preserve the optimal solution via a greedy strategy; substitute the exponential gravitational constant of the standard gravitational search (GS) algorithm with a linear function; improve the velocity update formula of the standard GS algorithm by mixing a adaptive weight and the global search strategy of the standard particle swarm optimization (PSO) algorithm. Benchmark examples are solved to demonstrate the proposed IGS algorithm is superior to the standard genetic algorithm, DE, GS, DE with local search, estimation of distribution algorithm and artificial bee colony algorithms. Two more examples from a real-world water-meter manufacturing enterprise are effectively solved
The Edinburgh Cognitive and Behavioural ALS Screen (ECAS) in frontotemporal dementia
No full textObjectivesTo examine the usefulness of the Edinburgh Cognitive and Behavioural Amyotrophic Lateral Sclerosis (ALS) Screen (ECAS) as a cognitive screening tool for the detection of behavioural variant FTD (bvFTD). A secondary aim was to determine whether people with FTD combined with ALS (ALS-FTD) exhibit a similar ECAS profile to that of people with bvFTD alone.MethodsPatients with ALS-FTD and bvFTD and healthy controls were recruited. Participants were administered the ECAS, which comprises tests of language, verbal fluency, executive functions, memory and visual spatial functions. They also carried out analogous, full-length cognitive tests that examine naming, spelling, sentence completion and social cognitionskills.ResultsThe study cohort comprised 20 ALS-FTD patients, 23 with bvFTD and 30 controls. Highly significant group differences were elicited for all cognitive domains, reflecting poorer performance in patients compared to controls. No significant differences in overall test scores were found between ALS-FTD and bvFTD patients, although ALS-FTD patients showed a higher frequency of impairment on verbal fluency. Correlative analyses revealed inter-relationships in patients (but not controls) between scores in different domains, mostmarked in bvFTD. There were strong correlations between performance on ECAS subtests and analogous cognitive tasks.ConclusionThe ECAS is a sensitive and valuable tool for the assessment of FTD. Executive, language and behavioural breakdown may, however, compromise performance in other cognitive domains, reducing the specificity of the ‘frontotemporal’ cognitive profile. Subtle differences observed between ALS-FTD and bvFTD raise questions regarding the precise relationship between bvFTD with and without ALS
An undergraduate laboratory experiment to build and characterise a thermionic triode for use as an audio amplifier.
No full textAlthough largely superseded by transistors for small signal amplification, the thermionic valve (or tube) still finds use in high-fidelity audio amplifiers, in guitar amplifiers and in high-power radio and television transmitters, where their power to size scalability has advantages over solid state devices. In the undergraduate experiments detailed here students construct a triode inside a vacuum chamber, and investigate the effects of different designs on signal gain. The characteristics of their triodes are measured to determine the optimal condition for signal amplification. The triode is then used to amplify an audio signal to determine the frequency response, and they can listen to the results via headphones using an input signal of their choice. This experiment hence introduces students to vacuum technology, to electron beams and to analogue electronics
The role of clinical pharmacy in preventing PEs in the emergency department of a governmental hospital in Jordan: a pre-post study
No full textBackgroundClinical pharmacists have an emerging role in the hospital emergency department, intercepting prescribing errors and improving patient safety; however, their impact within a Jordanian emergency department has never been studied.ObjectiveTo evaluate the impact of clinical pharmacy services on prescribing errors and assess predictors of physicians' acceptance of clinical pharmacists' interventions upon prescribing errors.SettingThis study was conducted in the emergency department (ED) of the largest governmental hospital in Jordan.MethodThis was a pre-post interventional study conducted over two months (October and November 2019) using a disguised direct observation method. The study was divided into two phases: a control phase where no clinical interventions were made, and an active phase where clinical pharmacists assigned to the ED prospectively observed, intervened and corrected errors. The clinical significance of detected errors was determined by a multidisciplinary committee. The Statistical Package for Social Science (SPSS) software Version 24 was used for data analysis.Main outcome measurePrescribing error incidence, error type, error severity, and predictors for physicians' acceptance.ResultsOf 18003 patients, 8732 were included in the control phase and 9271 in the active phase. Prescribing error incidence decreased from 24.6% to 5.4%. The proportion of contraindication, electronic drug selection, and wrong dosage form error types were significantly reduced from 32.6%, 9.1%, and 3.7% (P0 phase) to 12.6%, 0.0%, and 0.0% (P1 phase), respectively. Drug-Drug interaction, wrong drug frequency, and allergy error types were reduced from 4.9%, 3.1%, and 0.1% to 4.5%, 2.5%, and 0.0%, respectively however this was not statistically significant. The proportion of significant and serious errors was significantly reduced from 68.7% and 3.0% (P0 phase) to 8.9% and 1.8% (P1 phase), respectively. During the P1 phase, most errors were deemed minor (89.3%, 1574/1763), and lethal errors ceased. Predictors for physicians' acceptance were; significant errors (OR 3.1; 95%CI 2.6-4.3; p=0.03) and non-busy physicians (OR 2.1; 95%CI 1.6-2.7; p=0.04).ConclusionClinical pharmacists significantly reduced prescribing errors in the ED by 76%; most of their interventions were classed as significant. Policymakers should utilise our findings to implement active clinical pharmacy services in the ED.<br/
Patients’ Experiences of Deciding Whether or Not to Accept Bone Conduction Hearing Implants: A Qualitative Investigation
No full textObjectives: Bone conduction hearing implants (BCHIs) are an effective option to rehabilitate hearing for people who cannot use conventional, air-conduction hearing aids. However, the uptake of such devices in the UK is lower than might be expected, and the reasons for this are not fully understood. The present study used qualitative methods to explore decision-making about whether to accept or reject BCHIs.Design: Semi-structured telephone interviews were conducted with 17 BCHI candidates who had recently accepted or rejected BCHIs.Results: A thematic analysis identified four overarching themes: participants wanted to look and feel normal; potential risks were weighed against rewards; participants felt that there was a ‘right time’ to have a BCHI; information from clinicians and BCHI users was treated differently. Participants’ perceptions of normality were influential in the final decision, and the BHCI was seen either as a barrier or facilitator of this. Participants consistently weighed up potential advantages and disadvantages of BCHIs, with potential for hearing improvement typically used as a benchmark against which other factors were measured. Some participants who rejected BCHIs felt that they could reconsider having a BCHI when they felt the time was right for them. Participants highly valued advice from clinicians but felt that their expertise lacked validity as clinicians typically did not have experience of using BCHIs themselves. Conclusions: The decision to accept or reject the BCHI was highly individual. Each participant considered a range of factors; the influence of each factor depended on the individual’s perceptions and experiences. This work highlights the importance of clinical staff being able to explore the individual priorities and concerns of each patient to ensure that patients feel happy and confident with the decision that they make.<br/
Maloney and Smith method for modeling Debye media thin sheets in the FDTD grid
No full textThe Maloney and Smith method used to account for sheets thinner than the cell size of the FDTD method is extended to the case where both the sheet and the surrounding media are such dispersive Debye media as the Human Body tissues. The new method is then compared to the simpler Luebbers and Kuntz method that was previously extended to Debye media. The comparison relies on the reflection and transmission of plane waves and on three dimensional experiments. It is concluded that the Maloney and Smith method permits a better accuracy to be achieved. It provides accurate reflection and transmission whatever may be the incidence angle of the wave that strikes the sheet
Infection as a Stroke Risk Factor and Determinant of Outcome after Stroke
No full textUnderstanding the relationship between infection and stroke has taken on new urgency in the era of the coronavirus disease 19 (COVID-19) pandemic. This association is not a new concept, as several infections have long been recognized to contribute to stroke risk. The association of infection and stroke is also bidirectional. While infection can lead to stroke, stroke also induces immune suppression which increases risk of infection. Apart from their short-term effects, emerging evidence suggests that post-stroke immune changes may also adversely affect long-term cognitive outcomes in stroke patients, increasing the risk of post-stroke neurodegeneration and dementia. Infections at the time of stroke may also increase immune dysregulation after the stroke, further exacerbating the risk of cognitive decline. This review will cover the role of acute infections, including respiratory infections such as COVID-19, as a trigger for stroke; the role of infectious burden, or the cumulative number of infections throughout life, as a contributor to long-term risk of atherosclerotic disease and stroke; immune dysregulation after stroke and its effect on the risk of stroke-associated infection; and the impact of infection at the time of a stroke on the immune reaction to brain injury and subsequent long-term cognitive and functional outcomes. Finally, we will present a model to conceptualize the many relationships among chronic and acute infections and their short- and long-term neurological consequences. This model will suggest several directions for future research