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Modelling the adhesion enhancement at the wheel–rail interface: the role of surface roughness and plastic deformation during rail sanding operation
Get PDFEfficient train operation relies on optimal traction at the wheel–rail interface, which can be compromised by factors such as water and/or contamination (e.g. leaf, sand, oil, and surface abrasion debris). This study introduces a finite element model to assess adhesion enhancement at the wheel–rail interface, with a focus on the impact of sand particles during the sanding process. Surface roughness is initially introduced to quantify its effect on adhesion, followed by the inclusion of rail plastic deformation. By integrating these two factors, the model provides a comprehensive framework for evaluating the complex mechanisms influencing adhesion at the wheel–rail interface, particularly in real-world train operations where surface conditions interact with contaminants such as sand fragments. This approach addresses the existing gap in understanding how rail surface condition and rail plastic deformation contribute to adhesion enhancement during the sanding process, offering new insights for optimising railway maintenance strategies
Assessing climate change impacts on heat waves and heat index: a case study of Uttar Pradesh, India
Get PDFThe longitudinal effects of social media on sleep among youth:A scoping review
Get PDFSocial media has become an integral part of our everyday lives, with nearly 5 billion users worldwide. Its ubiquity has sparked concerns about the potential effects on sleep, particularly among young people. Previous research has generally shown that greater social media engagement is associated with poorer sleep outcomes, such as later bedtimes and longer sleep onset latency. However, most evidence is cross-sectional, limiting causal claims. This scoping review synthesises longitudinal studies published in the last five years examining the impact of social media use on subsequent sleep in young people. In accordance with cross-sectional findings, the majority of studies (∼70 %) provide evidence of a negative impact of social media use on bedtime and sleep onset latency, particularly in relation to problematic social media use, including at bedtime. However, methodological limitations, such as heavy reliance on self-reports and non-validated measures of social media use and sleep, restrict the strength of these conclusions. Future studies should employ validated measures and move beyond frequency-based metrics of social media to explore how content, patterns of problematic use, and the timing of use influence sleep longitudinally. It will also be important to consider bidirectional pathways and interactions with other key variables such as neurodiversity, socioeconomic status and mental health
The Lyrical Literature of Distant Listening
No full textDistant listening—a practice involving the capture of radio stations abroad and educated guesses about foreign languages and identification signals—meant a great deal to radio’s early listeners, many of whom were seduced by the aura of mystery surrounding sounds and voices originating from other countries and other parts of the globe. The radio journalism that flourished during the 1920s offers a full record of the craze, with numerous columns seeking to train wireless fans in the art of avoiding interferences and appreciating foreign stations. Building on recent scholarship by Simon Potter on distant listening and the BBC, and by Rebecca Scales on interwar French radio, this article examines how writers in France romanticized the figure of the distant listener during the late 1920s and early 1930s. The article contextualizes, then discusses a significant body of prose, poems, and journalistic essays by Fernand Divoire, Suzanne Malard, and Pierre Mac Orlan in which distant listening is the primary subject-matter. Taking into account their invocations of sovereignty, conquest, and invasion, the article shows that their lyrical representations of radio have a subtle political dimension, fueled by wider anxieties about national sovereignty, rearmament, and appeasement, and about the effectiveness of radio as a tool of propaganda as well as social cohesion. The article discusses Divoire’s, Malard’s, and Mac Orlan’s respective affiliations with nationalist and authoritarian currents running through the French right and concludes with a consideration of their respective wartime trajectories
‘Mum feels that the decision has already been made’:From shared decision-making to negotiated compromise in Adult Social Care
No full textAdult social care policies in England promise people choice and control over their care and support, often via a process of shared decision-making (SDM). An adult social care initiative – ‘single-handed care’ – involves care provided by two workers changing to a single worker using advanced equipment and techniques. We carried out interviews with key stakeholders (n=26) involved in single-handed care. This included people providing (homecare workers), assessing for (occupational therapists and social workers), and receiving single-handed care as well as family members. Interviews were transcribed verbatim and analysed using standard qualitative processes and thematic analysis. We identified that the people receiving the service, family members and homecare workers sometimes felt that the decision to move to single-handed care had been made by the assessors before the SDM process began. The successful organisation of single-handed care required SDM to be balanced with competing responsibilities towards professional authority and accountability, and fiscal responsibility. Where there was a disagreement between stakeholders about a move to single-handed care tensions between these three responsibilities emerged. We argue that social care policies and procedures need to be more explicit about the extent to which decisions can be shared and that there may need to be a process of ‘negotiated compromise’ which sometimes allows other responsibilities to prevail
Unpacking the Gendered Impact of Scarcity Cues and Customer Ratings on Online Hotel Bookings and Recommendations
Get PDFTo drive conversions, e-commerce and m-commerce platforms often employ various scarcity cues within their booking interfaces. These fall into two categories: limited-quantity (e.g., "Last room available!") and limited-time (e.g., "Offer ends in 3 hours!"). The utility of such cues extends to hotels, regardless of their overall customer ratings. Meanwhile, although gender serves as one of the primary factors for market segmentation, the differential reactions of men and women to various marketing cues within the online marketplace have not been thoroughly investigated. Hence, this paper investigates how gender influences consumers’ booking and recommendation intentions in response to scarcity cues for hotels with varying customer ratings. An online experiment (N = 385, 181 men and 204 women) was conducted. It manipulated scarcity cue type (limited-quantity and limited-time) and customer ratings (high and low) as between-participants factors. Booking intention was generally higher among men. This was particularly true under conditions of limited-quantity scarcity and high customer ratings. Moreover, men exhibited a higher intention to recommend compared with women when facing limited-quantity scarcity. The findings deepen the scholarly understanding of the gendered impact of scarcity cues and customer ratings on online hotel bookings and recommendations
The effect of computer guided total hip replacement on risk of revision, Oxford Hip Score, and health related quality of life: an analysis of National Joint Registry data
Get PDFBackground
Total hip replacement (THR) can be performed conventionally or with the assistance of computer guidance systems. We aimed to compare the risk of revision for all-causes and dislocation, and differences in Oxford Hip Score (OHS) and health-related quality of life (EQ-5D-3L) following primary THR performed conventionally versus with the assistance of computer guidance systems.
Methods
We performed an observational study using National Joint Registry data. Adult patients who underwent primary THR for osteoarthritis between 2003 and 2020 were included. The co-primary analyses were revision for all-causes and dislocation. Secondary analyses were differences in OHS and EQ-5D-3L. Weights based on propensity scores were generated. Cox proportional hazards and generalised linear models were used to assess outcomes of revision, OHS, and EQ-5D-3L. Effective sample sizes (ESS) were computed.
Results
Risk of revision for all-causes comparing computer guided and conventional THR were similar (HR 0.947, 95% CI 0.698–1.283, p = 0.726, ESS 7235). However, sensitivity analysis restricting to the five most commonly used combination of prosthesis brands demonstrated reduced revision risk in favour of computer guidance (HR 0.446, 95% CI 0.231–0.858, p = 0.016, ESS 3993). There was no difference in revision for dislocation between groups (HR 0.929, 95% CI 0.512–1.688, p = 0.810, ESS 7235). Compared to conventional THR, the use of computer guidance increased OHS by 0.931 (95% CI 0.308–1.554, p = 0.003, ESS 2112) however there were no differences in EQ-5D-3L (0.007, 95% CI −0.008–0.023, p = 0.356, ESS 2929). Incidence of intra-operative complications was significantly fewer during computer guided THR (0.51% versus 0.96%, p = 0.006).
Conclusions
There were no differences in revision for all-causes and dislocation between computer guided and conventional THR. However, sensitivity analysis considering only the five most commonly used prosthesis brands demonstrated a reduced risk of revision for all-causes favouring computer guided THR. Furthermore, computer guidance was associated with a significant but minimal improvement in OHS and a lower risk of intra-operative complications, without differences in EQ-5D-3L. Although these findings suggest potential for computer guided THR to improve implant survivorship and reduce intra-operative complications, they require cautious interpretation given the limitations inherent to observational study designs and registry based analyses
Species Contributions to Biotic Homogenisation and Differentiation
Get PDFAim Homogenisation (decreasing beta-diversity) among biological assemblages is often interpreted as being caused by already-widespread species increasing. The link between individual species level trends and homogenisation between assemblages, however, has not been fully addressed, with most studies focused solely on either assemblage level or species level changes. Here we aim to test the widely held hypothesis that homogenisation is driven by the decrease of localised species and increase of those already widespread using species contribution to beta-diversity. Location North America, Europe, South Africa. Time Period 1970 to 2019, 1966 to 1996, 11,700 years ago to present, 2011 to 2021, 1960 to 2016. Major Taxa Studied Birds, plants, benthos and mammals. Methods Here, we consider individual species contributions to spatial beta-diversity and how these change over time. We focus on the relative contributions of localised and widespread species across five case studies to determine which are contributing most to homogenisation. Results Species occurring in around half of sites provided the greatest contributions to beta-diversity at a given time, but not through time. The most widespread species (> 0.75 of sites) contributed little to beta-diversity change, with this most apparent in highly nested assemblages. In contrast, localised species (initially in < 0.25 of sites) contributed most to both homogenisation (when declining) and differentiation (when increasing) regardless of nestedness. Main Conclusions This challenges the hypothesis that widespread generalist species are the main drivers of homogenisation, underlining the importance of rare species and of nestedness to patterns of beta-diversity change. Conservation interventions to increase localised species occurrence would do more to limit homogenisation than attempts to control already-widespread species or prevent others becoming widespread, especially when assemblages are highly nested
Overfitting, regularisation and condition estimation in regression
Get PDFOverfitting is a problem in regression and deep neural networks, and it is often stated that Tikhonov regularisation minimises its adverse effects, but the relationship between regularisation and overfitting has not been established. The theory of regularisation is well developed, but overfitting has a qualitative description and it is not defined mathematically. This paper addresses the relationship between overfitting, regularisation and condition estimation by considering underdetermined and overdetermined least squares (LS) problems that arise in regression. This study is important because regularisation is not benign since its use when a condition on the decay of the singular values of the coefficient matrix in the LS minimisation is not satisfied leads to a large error in the solution of the regularised LS problem. Examples in which the regression curve overfits the data are shown, but regularisation must not be applied because the LS problem is well conditioned. Also, an ill conditioned LS problem whose solution does not display overfitting is shown, but its ill conditioned nature implies regularisation should be applied in order to obtain a numerically stable solution. It is concluded that regularisation does not solve the problem of overfitting in regression
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