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Reflections on the forum in the Review of International Studies:A conversation between Cristina Masters and Marysia Zalewski
No full textEnvironmental trade-offs associated with bioenergy from agri-residues in sub-tropical regions: A case study of the Colombian coffee sector
No full textThe coffee sector generates vast amounts of residues along its value chain. Crop residues, like coffee stems, are burned in the field, used for domestic cooking or coffee drying in processing plants having significant environmental and health implication to rural communities. This research investigated the environmental impacts of replacing current practices with modern bioenergy applications in the Colombian coffee sector. A biomass gasification system to produce decentralised energy from coffee stems was considered, and the environmental impacts of such bioenergy implementation were evaluated. A lifecycle assessment was conducted to quantify the environmental performance of this bioenergy system and compare it to current residues uses and energy needs that feature small- to large-scale coffee farms. The results show that deploying modern bioenergy could result in reductions in 48-86% greenhouse gas (GHG) emissions and up to 98% less particulate matter formation when current practices and fossil-based energy are replaced. However, negative impacts should be considered as substituting grid electricity, largely generated from hydro-electricity, could increase GHGs by 68% and fossil fuel consumption by 73%. The results also show the relevance of understanding the environmental performance of bioenergy systems compared to reference scenarios; this allowed to evaluate and identify environmental trade-offs from modern bioenergy implementations. To maximise benefits and minimise the limitations of these systems, it is important to conduct whole-system assessments that inform on the wider environmental impacts of using agri-residues for bioenergy generation in a region- and system-specific context
The Level of Evidence, Scientific Impact and Social Impact of Clinical Studies in Periodontology: A Methodological Study
No full textAims: To analyze the level of evidence (LOE) of clinical studies in the field of periodontology, and to investigate whether LOE is a predictor of scientific impact and social impact. Materials and Methods: All clinical studies published in five leading periodontal journals during 2015 - 2019 were identified and screened for eligibility. The LOE of the included studies were assessed with a modified Oxford 2011 LOE tool. Citation counts and Altmetric Attention Scores (AAS) were harvested from Web of Science and Altmetric Explorer, respectively. In addition, multivariable generalized estimation equation (GEE) analyses were used to investigate associations among LOE, citation count and AAS. Results: A total of 768 clinical studies in periodontology were included, among which the proportion of level-1, level-2, level-3, and level-4 studies was 10.4%, 44.8%, 13.5%, and 31.3%, respectively. In the multivariable GEE analyses, high LOE was a significant predictor of higher citation count (P=0.016) and higher AAS (P<0.001). Conclusion: The LOE of clinical studies in the periodontal field is relatively high in general, although it varies significantly in different journals. Studies with high LOE tend to have greater scientific impact and social impact than low LOE studies
Fast Approximate Bayesian Contextual Cold Start Learning (FAB-COST)
No full textCold-start is a notoriously difficult problem which can occur in recommendation systems, and arises when there is insufficient information to draw inferences for users or items. To address this challenge, we propose a contextual bandit algorithm that we call the Fast Approximate Bayesian Contextual Cold Start Learning algorithm (FAB-COST), which is designed to provide improved accuracy compared to the traditionally used Laplace approximation in the logistic contextual bandit, while controlling both algorithmic complexity and computational cost. To this end, FAB-COST uses a combination of two moment projection variational methods: Expectation Propagation (EP), which performs well at the cold start, but becomes slow as the amount of data increases; and Assumed Density Filtering (ADF), which has slower growth of computational cost with data size but requires more data to obtain an acceptable level of accuracy. By switching from EP to ADF when the dataset becomes large, we are able to exploit their complementary strengths. Here, we present the empirical justification for FAB-COST, and systematically compare it to other approaches on simulated data. In a benchmark against the Laplace approximation on real data consisting of around 31, 000 impressions from autotrader.co.uk, we demonstrate an increase in number of user clicks of over 16%. On the basis of our results, we argue that FAB-COST is likely to be an attractive approach to cold-start recommendation systems in a variety of contexts
What are the barriers to physical activity in patients with chronic plaque psoriasis?
No full textBackgroundPsoriasis is associated with an increased risk of cardiovascular disease (CVD). Despite recommendation that exercise is important for cardiorespiratory fitness, patients with psoriasis avoid participation in physical activities for reasons which are, as yet, unclear.ObjectivesThis study investigated the relationship between psoriasis-specific experiences and self-reported patterns of exercise, hypothesising that individuals with psoriasis are less likely to engage in physical activity for reasons which are related to their psoriasis. Methods404 patients with chronic plaque psoriasis were recruited. History, examination and physical activity was assessed for each participant.Results52.8% (n=188) of patients with psoriasis aged 18 to 65 and 66.1% (n=37) of those over 65 engaged in less than the recommended amount of physical activity for cardiorespiratory fitness. As the severity and psychosocial impact of psoriasis increased the participation in exercise (of all intensities) decreased: significant negative correlation between Psoriasis Area and Severity Index and total activity in females aged 18 to 65 (r = -0.187, 95% confidence interval [CI] -0.36 - 0, p = 0.04), and significant negative correlation between physical activity and Dermatology Life Quality Index (DLQI) in all participants (r = -0.109, 95% CI -0.21 - 0, p = 0.04). Individual components of the DLQI identified barriers to physical activity including skin sensitivity and reluctance to participate in leisure activities.ConclusionPsoriasis-specific factors - severity, skin sensitivity, clothing choice, participation in social / leisure activities and treatments - contribute to exercise avoidance and may augment the increased risk of CVD in patients with psoriasis
Relationship of anabolic hormones with motor unit characteristics in quadriceps muscle in healthy and frail ageing men
No full textContext: Anabolic hormones are important factors in maintaining muscle mass for ageing men, but their role in overall motor unit structure and function is unclear. Objective: To determine associations of anabolic and reproductive hormone levels with motor unit characteristics in quadriceps muscle in older healthy and frail men. Design: Observational cohort study of community dwelling men. Participants: Healthy and frail men > 65 years old. Intervention: None. Outcome measure: Quantitative assessments of electromyography-derived motor unit potential size (MUP) and compound muscle action potential size (CMAP) of vastus lateralis muscle. Results: We studied 98 men (mean±SD: age 73±6 years; BMI 25.7±4.0 kg/m2; diabetes 11%) of whom 45% were prefrail and 18% frail. After adjusting for age, BMI and prevalent diabetes, higher total and free testosterone levels were significantly related to larger CMAP (total testosterone: β (95% CI): 0.3 (0.08, 0.53); free testosterone: 0.34 (0.13, 0.56)). Exploratory analysis showed the relationship between free testosterone and CMAP was stronger in frail rather than robust men. In univariate analyses, estradiol was associated with CMAP size (0.37 (0.16, 0.57)); and vitamin D was associated with MUP size (0.22 (0.01, 0.43)) but these relationships were no longer significant after adjusting for potential confounders. Conclusion: Our data highlight the associations between androgen levels and the electrophysiological characteristics of older men, particularly in the frail. Clinical trials involving administration of androgens will help to elucidate the potential benefits of intervention on neuromuscular function and/or frailty status
Viral breedings: HIV as pregnancy among bugchasers
No full textBugchasing is the fetishization of HIV among some gay men. Bugchasers, who thrive in online forums and social media, have generated complex subcultural narratives of the virus as a vehicle for intimacy, connection, and masculinity. While this practice has been addressed from public health and media studies, relatively little analysis has been conducted on their sex stories. In this article, I use the sex story 'Andy is HIV+' to explore how bugchasers appropriate the language of both HIV prevention and heterosexual reproduction to narrate new forms of vertical and horizontal kinship. These new forms are articulated through HIV infection: bugchasers 'breed' each other with their 'poz babies' and become 'brothers' and 'lovers.' While Dean (2009) has already discussed bugchasing kinship, I explore the practical implementation of these forms of relationality to address existing gaps in the literature. In the second part of this article, I also complicate existing research on bugchasing kinship by considering how the fictional nature of the materials under analyses problematizes our theoretical developments and our assumptions about the men producing the texts. In particular, I suggest that theoretical research on kinship should be accompanied by in-depth consideration of how fictional narratives translate into lived experience
Seeking sustainable futures in marketing and consumer research
No full textPurpose Seeking ways towards a sustainable future is the most dominant socio-political challenge of our time. Marketing should have a crucial role to play in leading research and impact in sustainability, yet it is limited by relying on cognitive behavioural theories rooted in the 1970s, which have proved to have little bearing on actual behaviour. This paper interrogates why marketing is failing to address the challenge of sustainability, and identifies alternative approaches.Design/methodology The constraint in theoretical development contextualises the problem, followed by a focus on four key themes to promote theory development: developing sustainable people; models of alternative consumption; building towards sustainable marketplaces; and theoretical domains for the future. These themes were developed and refined during the 2018 Academy of Marketing workshop on seeking sustainable futures. MacInnis’s (2011) framework for conceptual contributions in marketing provides the narrative thread and structure.Findings The current state of play is explicated, combining the four themes and MacInnis’s framework to identify the failures and gaps in extant approaches to the field.Research Implications This paper sets a new research agenda for the marketing discipline in our quest for sustainable futures in marketing and consumer research.Practical Implications Approaches are proposed which will allow the transformation of the dominant socio-economic systems towards a model capable of promoting a sustainable future.Originality/value The paper provides thought leadership in marketing and sustainability as befits the special issue, by moving beyond description of the problem to making a conceptual contribution and setting a research agenda for the future
Unravelling effects of the pore-size correlation length on the two-phase flow and solute transport properties; GPU-based pore-network modelling
No full textContinuum-scale models for two-phase flow and transport in porous media are based on the empirical constitutive relations that highly depend on the porous medium heterogeneity at multiple scales including the microscale pore-size correlation length. The pore-size correlation length determines the representative elementary volume and controls the immiscible two-phase invasion pattern and fluids occupancy. The fluids occupancy not only controls the shape of relative permeability curves but also the transport zonation under two-phase flow conditions, which results in the non-Fickian transport. This study aims to quantify the signature of the pore-size correlation length on two-phase flow and solute transport properties such as the capillary pressure- and relative permeability-saturation, dispersivity, stagnant saturation, andmass transfer rate. Given the capability of pore-scale models in capturing the pore morphology and detailed physics of flow and transport, a novel GPU-based pore-network model has been developed. This GPU-based model allows us to simulate flow and transport in networks with multi-millions pores, equivalent to the centimetre length scale. The impact of the pore-size correlation length on all aforementioned properties was studied and quantified. Moreover, by classification of the pore space to flowing and stagnant regions, a simple semi-analytical relation for the mass transfer between the flowing and stagnant regions was derived, which showed a very good agreement with pore-network simulation results. Results indicate that the characterization of the topology of the stagnant regions as a function of pore-size correlation length is essential for a better estimation of the two-phase flow and solute transport properties
Lasting modulation of human cortical swallowing motor pathways following thermal tongue stimulation.
No full textPurpose: Thermal tactile oropharyngeal stimulation has been clinically used to facilitate swallowing initiation in dysphagic patients. We previously demonstrated that thermal stimulation applied to the oral cavity provokes an immediate excitability in pharyngeal motor cortex. The aim of the current study was to investigate whether thermal stimulation can produce longer lasting effects on the cortico-pharyngeal neural pathway. Material and Methods: Healthy volunteers (n=8/12) underwent baseline pharyngeal motor evoked potential (PMEP) measurements evoked by transcranial magnetic stimulation. In the first experiment, subjects received thermal stimulation alternating 30 s of 15 degrees Celsius (°C) and 36°C applied to the tongue surface for either 10 minutes, 5 minutes, or sham. In the second experiment, one of three intermittent thermal stimulus patterns was delivered; cold (alternating 30 s of 15 °C and 36°C), warm (continuous 36 °C) or hot (alternating 30 s of 45 °C and 36°C) for 10 minutes. In both experiments, PMEPs were re-measured every 15 minutes up to 60 minutes following thermal stimulation. Results: Repeated measures ANOVA for each stimulus time in the first experiment showed a significant increased change in PMEP amplitude at 30 minutes following only 10-minutes stimulation compared to sham (p < 0.05). In the second experiment, we found that cold stimulation was more effective than the other stimulation (p < 0.05) at increasing PMEP amplitudes. Conclusions: Ten minutes cold stimulation on the tongue can induce a delayed (30 min) increase in pharyngeal cortical excitability, providing a clinically useful therapeutic window for its application in dysphagic patients