6664 research outputs found
Sort by
Experimental and numerical investigation on the size effect of Ultrahigh-Performance Fibre-Reinforced Concrete (UHFRC)
Get PDFIn the last few years, there has been increasing interest in the use of Ultrahigh-Performance Fibre-Reinforced Concrete (UHPFRC) layers or jackets, which have been proved to be quite effective in strengthening applications. However, to facilitate the extensive use of UHPFRC in strengthening applications, reliable numerical models need to be developed. In the case of UHPFRC, it is common practice to perform either direct tensile or flexural tests to determine the UHPFRC tensile stress–strain models. However, the geometry of the specimens used for the material characterization is, in most cases, significantly different to the geometry of the layers used in strengthening applications which are normally of quite small thickness. Therefore, and since the material properties of UHPFRC are highly dependent on the dimensions of the examined specimens, the so called “size effect” needs to be considered for the development of an improved modelling approach. In this study, direct tensile tests have been used and a constitutive model for the tensile behaviour of UHPFRC is proposed, taking into consideration the size of the finite elements. The efficiency and reliability of the proposed approach has been validated using experimental data on prisms with different geometries, tested in flexure and in direct tension
SARS-CoV-2 routes of transmission and recommendations for preventing acquisition: joint British Infection Association (BIA), Healthcare Infection Society (HIS), Infection Prevention Society (IPS) and Royal College of Pathologists (RCPath) guidance
Get PDFThe pandemic of the coronavirus disease 2019 (COVID-19),
caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged amid uncertainty about the dynamics of transmission and the possible management options for COVID-19 patients. This resulted in confusion for healthcare workers (HCWs) and hospital managers who often received conflicting advice on how to organise care and manage infected individuals without increasing the risk of transmission to HCWs and other patients. Advice for the public has also been confusing and apparently sometimes contradictory, which sometimes resulted in overuse of Personal Protective Equipment(PPE) in the general population as well as in healthcare workers. As evidence from the first wave has emerged, we are now in a position to summarise it and provide guidance on how to prevent SARS-CoV-2 transmission whilst preserving essential resources. This article is the first of two guidance documents
produced jointly by the Healthcare Infection Society, British Infection Association, Infection Prevention Society and Royal College of Pathologists. This guidance article describes routes of SARS-CoV-2 transmission, which will allow the public and healthcare professionals to understand how SARS-CoV-2 transmission occurs. By determining how likely transmission can occur via a given route, we can extrapolate the evidence for infection prevention and control (IPC) and apply this knowledge to optimise protection from SARS-CoV-2 infection.
At the time of writing (April 2021), new variants of SARS-CoV-2 emerged, raising concerns whether the virus could make current vaccines ineffective. The evidence strongly suggests that these variants have a transmission potential higher than the original virus thus, strict adherence to IPC measures is still required in breaking the chain of SARS-CoV-2 transmission.
Further review may be required as more evidence about these
variants becomes available.
On review of the evidence, the COVID-19 Rapid Guidance
Working Party considers the different transmission routes as
follows:
droplet transmission: probable
transmission via fomites: possible
airborne transmission: possible (in some circumstances,
e.g., aerosol generating procedures (AGPs)
transmission via ocular surface: possible
vertical transmission: unlikely
transmission from different body fluids (other than respiratory secretions and saliva): unlikely
transmission from blood transfusion and transplantation
organs: unlikely
The Working Party concludes that transmission most often
occurs following close contact, especially where PPE is not
worn, as reflected in high transmission rates between family
members, friends, and co-workers. At the moment it is not
possible to determine the distance or the duration over which transmission can occur, although these vary depending on circumstances (e.g. the shorter the distance, the shorter the duration of contact will be required, but also on environmental and other factors). Transmission from COVID-19 patients to HCWs in hospitals is low, except in a small number of cases where HCWs cared for undiagnosed COVID-19 patients and did
not use appropriate PPE. Even in these cases, transmission
usually occurs during AGPs. Transmission in care homes appears to be very high and anecdotal evidence suggests that there were difficulties in obtaining appropriate PPE and observing social distancing during the pandemic. The published literature is not comprehensive enough to make recommendations for this setting. However, considering there is no IPC guidance specific for care homes, we suggest that staff in these institutions follow the recommendations for persons working in health and care settings listed below and that they explore aspects specific to their local institutions to address the barriers which prevent
them in doing so, e.g. inability to maintain social distancing
Learning from a cascading crisis: a framework for crisis learning stewardship
No full textAlthough these ideas are deeply rooted in crisis management practice over the last 20 years, several studies have shown that learning from crises in many organizations is either poor or does not take place at all (c.f. Elliott, 2009; Smith & Elliott, 2007; Stemn et al., 2018). Some studies (Broekema et al., 2017; Herbane, 2018) point that learning takes place but that some organizations learn from their crises better and faster than others. There is a wider consensus that learning from a crisis can be both complex and challenging since crises often are very unique and unpredictable situations in which complex circumstances of uncertainty and chaos, lack of credible and reliable information, siloed organizational structures and departmental tribalism make it difficult to distill clear crisis lessons (Boin et al., 2017; Paraskevas & Altinay, 2013). However, the factors that drive effective organizational learning from a crisis are still contested in the literature (Deverell, 2009; Drupsteen & Guldenmund, 2014).
This chapter aims to provide some more clarity on these factors by exploring the drivers of learning in Japanese hotel chains from the 2011 Great East Japan Earthquake and Tsunami. It starts with a brief review of the organizational learning literature to make the distinction between organizational learning and crisis-induced learning and sets the context of the research by an overview of the crisis under which the organizational learning was distilled and/or implemented. It then discusses the findings of the study and presents a framework of drivers for crisis learning stewardship
Conclusion: towards a research agenda for organizational learning in crisis management
No full textTo date, most hospitality and tourism scholars that conceptualized organizational learning from a crisis have relied on a limited set of theories such as Argyris and Schön’s (1978) single and double-loop learning, Huber’s (1991) information processing model, March’s (1991) exploration-exploitation framework, and Senge’s (1990) learning organization. These theories are largely considered functionalist in the sense that they seek organizational change and effectiveness from crisis lessons rather than an understanding and a possible change of power and agency within the organization for more effective learning or changes in sense-making and identity. Therefore, a good starting point would be for future research to embrace other paradigms by moving away from the current functionalist approaches of crisis learning towards other theoretical paradigms that have shaped the organizational learning field over time such as the community-of-practice-based approach (Lave & Wenger, 1991), social network theory (Zhao & Anand, 2013), and critical theory (Fenwick, 2003). While empirical studies on crisis learning in hospitality and tourism are limited, this book has identified and explored several areas in which further research is needed
Environmental hygiene, knowledge and cleaning practice: a phenomenological study of nurses and midwives during COVID-19
No full textBackground
Environmental cleanliness is a fundamental tenet in nursing and midwifery but often overshadowed in practice. This study explored nurses’ and midwives’ knowledge and experiences of infection prevention and control (IPC) processes and cleaning, and perceptions about workplace risk-management during COVID-19.
Methods
Six registered and enrolled nurses (one with dual midwife qualifications) were recruited. In-depth telephone interviews were analyzed using Colaizzi's phenomenological method.
Results
Four major themes were identified: Striving towards environmental cleanliness; Knowledge and learning feeds good practice; There's always doubt in the back of your mind; and COVID has cracked it wide open. These articulate the nurses’ and midwives’ experiences and knowledge of IPC, particularly during COVID-19.
Discussion
The findings emphasize the dynamic, interdependent nature of clinical (time, staff knowledge and compliance, work processes, hospital design) and organizational contexts and environmental cleanliness, which must be constantly maintained. COVID-19 opened up critical insights regarding poor past practices and lack of IPC compliance.
Conclusions
COVID-19 has highlighted the criticality of environmental cleanliness within clinical and community settings. Evidence-based, experiential learning is important for nurses and midwives at all career stages, but provides only one solution. Clinician-led hospital design may also reduce the spread of infection; thus, promoting better patient care
Anopheles coluzzii stearoyl-CoA desaturase is essential for adult female survival and reproduction upon blood feeding
No full textVitellogenesis and oocyte maturation require anautogenous female Anopheles mosquitoes to obtain a bloodmeal from a vertebrate host. The bloodmeal is rich in proteins that are readily broken down into amino acids in the midgut lumen and absorbed by the midgut epithelial cells where they are converted into lipids and then transported to other tissues including ovaries. The stearoyl-CoA desaturase (SCD) plays a pivotal role in this process by converting saturated (SFAs) to unsaturated (UFAs) fatty acids; the latter being essential for maintaining cell membrane fluidity amongst other housekeeping functions. Here, we report the functional and phenotypic characterization of SCD1 in the malaria vector mosquito Anopheles coluzzii. We show that RNA interference (RNAi) silencing of SCD1 and administration of sterculic acid (SA), a small molecule inhibitor of SCD1, significantly impact on the survival and reproduction of female mosquitoes following blood feeding. Microscopic observations reveal that the mosquito thorax is quickly filled with blood, a phenomenon likely caused by the collapse of midgut epithelial cell membranes, and that epithelial cells are depleted of lipid droplets and oocytes fail to mature. Transcriptional profiling shows that genes involved in protein, lipid and carbohydrate metabolism and immunity-related genes are the most affected by SCD1 knock down (KD) in blood-fed mosquitoes. Metabolic profiling reveals that these mosquitoes exhibit increased amounts of saturated fatty acids and TCA cycle intermediates, highlighting the biochemical framework by which the SCD1 KD phenotype manifests as a result of a detrimental metabolic syndrome. Accumulation of SFAs is also the likely cause of the potent immune response observed in the absence of infection, which resembles an auto-inflammatory condition. These data provide insights into mosquito bloodmeal metabolism and lipid homeostasis and could inform efforts to develop novel interventions against mosquito-borne diseases
A Machine Learning Scheme for Estimating the Diameter of Reinforcing Bars Using Ground Penetrating Radar
Get PDFGround penetrating radar (GPR) is a well-established tool for detecting and locating reinforcing bars (rebars) in concrete structures. However, using GPR to quantify the diameter of rebars is a challenging problem that current processing approaches fail to tackle. To that extent, we have developed a novel machine learning framework that can estimate the diameter of the investigated rebar within the resolution range of the employed antenna. The suggested approach combines neural networks and a random forest regression and has been trained entirely using synthetic data. Although the training process relied only on numerical training sets, nonetheless, the suggested scheme is successfully evaluated with real data indicating the generalization capabilities of the resulting regression. The only required input of the proposed technique is a single A-scan, avoiding laborious measurement configurations and multisensor approaches. In addition, the results are provided in real time and making this method practical and commercially appealing
Eye Accommodation Sensing for Adaptive Focus Adjustment.
No full textOver 2 billion people across the world are affected by some visual impairment – mostly related to optical issues, and this number is estimated to grow. Often, particularly in the elderly, more than one condition can affect the eyes at the same time, e.g., myopia and presbyopia. Bifocal or multifocal lenses can be used, these however may become uncomfortable or disturbing and are not adapted to the user. There is therefore a need and opportunity for a new type of glasses able to adaptively change the lenses’ focus. This paper explores the feasibility of recording the eye accommodation process in a non-invasive way using a wearable device. This can provide a way to measure eye convergence in real-time to determine what a person’s eye is focused on. In this study, Electro-oculography (EoG) is used to observe eye muscle activity and estimate eye movement. To assess this, a group of 11 participants we each asked to switch their gaze from a near to far target and vice versa, whilst their EoG was measured. This revealed two distinct waveforms: one for the transition from a far to near target, and one for the transition from a near to far target. This informed the design of a correlation-based classifier to detect which signals are related to a far to near, or near to far transition. This achieved a classification accuracy of 97.9±1.37% across the experimental results gathered from our 11 participants. This pilot data provides a basic starting point to justify future device development
Uncertainties in non-domestic energy performance certificate generating in the UK
Get PDFIn light of the recent launch of the Minimum Energy Efficiency Standard targeting the energy performance of commercial buildings, this study compares the energy performance certificates of three UK hotels generated by two different software, EDSL TAS and SBEM, both accredited by the UK government for the purpose. Upon finding the results discrepant, the study finds that the two software’s different assumptions for the air permeability rate contribute to the discrepancy. While modifying this value makes the results from the two software more aligned, further issues regarding the validation process arise. The study continues to find that the underlying issue can be found within the National Calculation Methodology’s assumption about domestic hot water consumption in hotels. These assumptions are compulsory to follow when generating a non-domestic energy performance certificate in the UK, therefore, any uncertainties within them can affect all the buildings seeking an energy performance certificate within that sector. Finally, the study discusses that, for meeting the carbon dioxide mitigation goals, it is necessary to make changes to the current procedure of energy performance certificate generating in the UK to increase its reliability