Particle Collisions on Stringy Black Hole Background

The collision of two particles in the background of a Sen black hole is studied. With the equations of motion of the particles, the center-of-mass energy is investigated when the collision takes place at the horizon of a Sen black hole. For an extremal Sen black hole, we find that the center-of-mass energy will be arbitrarily high with two conditions: (1) spin $a\neq 0$ and (2) one of the colliding particles has the critical angular momentum $l_{\text{c}}=2$. For a nonextremal Sen black hole, we show that, in order to obtain an unlimited center-of-mass energy, one of the colliding particles should have the critical angular momentum $l'_{\text{c}}=2 r_{+}/a$ ($r_{+}$ is the radius of the outer horizon for a nonextremal black hole). However, a particle with the angular momentum $l=l'_{\text{c}}$ could not approach the black hole from outside of the horizon through free fall, which implies that the collision with arbitrarily high center-of-mass energy could not take place. Thus, there is an upper bound of the center-of-mass energy for the nonextremal black hole. We also obtain the maximal center-of-mass energy for a near-extremal black hole and the result implies that the Planck-scale energy is hard to be approached. Furthermore, we also consider the back-reaction effects. The result shows that, neglecting the gravitational radiation, it has a weak effect on the center-of-mass energy. However, we argue that the maximum allowed center-of-mass energy will be greatly reduced to below the Planck-scale when the gravitational radiation is included.Comment: 17 pages, 4 figures, published versio

The impact of interventions to promote healthier ready-to-eat meals (to eat in, to take away or to be delivered) sold by specific food outlets open to the general public: a systematic review.

INTRODUCTION: Ready-to-eat meals sold by food outlets that are accessible to the general public are an important target for public health intervention. We conducted a systematic review to assess the impact of such interventions. METHODS: Studies of any design and duration that included any consumer-level or food-outlet-level before-and-after data were included. RESULTS: Thirty studies describing 34 interventions were categorized by type and coded against the Nuffield intervention ladder: restrict choice = trans fat law (n = 1), changing pre-packed children's meal content (n = 1) and food outlet award schemes (n = 2); guide choice = price increases for unhealthier choices (n = 1), incentive (contingent reward) (n = 1) and price decreases for healthier choices (n = 2); enable choice = signposting (highlighting healthier/unhealthier options) (n = 10) and telemarketing (offering support for the provision of healthier options to businesses via telephone) (n = 2); and provide information = calorie labelling law (n = 12), voluntary nutrient labelling (n = 1) and personalized receipts (n = 1). Most interventions were aimed at adults in US fast food chains and assessed customer-level outcomes. More 'intrusive' interventions that restricted or guided choice generally showed a positive impact on food-outlet-level and customer-level outcomes. However, interventions that simply provided information or enabled choice had a negligible impact. CONCLUSION: Interventions to promote healthier ready-to-eat meals sold by food outlets should restrict choice or guide choice through incentives/disincentives. Public health policies and practice that simply involve providing information are unlikely to be effective

Disfluency in dialogue:an intentional signal from the speaker?

Disfluency is a characteristic feature of spontaneous human speech, commonly seen as a consequence of problems with production. However, the question remains open as to why speakers are disfluent: Is it a mechanical by-product of planning difficulty, or do speakers use disfluency in dialogue to manage listeners' expectations? To address this question, we present two experiments investigating the production of disfluency in monologue and dialogue situations. Dialogue affected the linguistic choices made by participants, who aligned on referring expressions by choosing less frequent names for ambiguous images where those names had previously been mentioned. However, participants were no more disfluent in dialogue than in monologue situations, and the distribution of types of disfluency used remained constant. Our evidence rules out at least a straightforward interpretation of the view that disfluencies are an intentional signal in dialogue. © 2012 Psychonomic Society, Inc

Gravitational collapse with tachyon field and barotropic fluid

A particular class of space-time, with a tachyon field, \phi, and a barotropic fluid constituting the matter content, is considered herein as a model for gravitational collapse. For simplicity, the tachyon potential is assumed to be of inverse square form i.e., V(\phi) \sim \phi^{-2}. Our purpose, by making use of the specific kinematical features of the tachyon, which are rather different from a standard scalar field, is to establish the several types of asymptotic behavior that our matter content induces. Employing a dynamical system analysis, complemented by a thorough numerical study, we find classical solutions corresponding to a naked singularity or a black hole formation. In particular, there is a subset where the fluid and tachyon participate in an interesting tracking behaviour, depending sensitively on the initial conditions for the energy densities of the tachyon field and barotropic fluid. Two other classes of solutions are present, corresponding respectively, to either a tachyon or a barotropic fluid regime. Which of these emerges as dominant, will depend on the choice of the barotropic parameter, \gamma. Furthermore, these collapsing scenarios both have as final state the formation of a black hole.Comment: 18 pages, 7 figures. v3: minor changes. Final version to appear in GR

Barriers and enablers to engagement with a type 2 diabetes remission project in the North East of England: Qualitative perspectives of patients

\ua9 The Author(s), 2024.This qualitative research sought to identify factors influencing patient choice of, and patient-related internal and external enablers and barriers to engagement with, type 2 diabetes (T2D) remission strategies offered by the Remission in diabetes (REMI.D) project. Patients had a choice of three diets: Total Diet Replacement (TDR)-Formula Food Products, TDR-Food, and Healthy lifestyle approach; and three activity pathways: Everyday life, General Practitioner referral, and Social hub. Semi-structured interviews were recorded and transcribed. Thematic analysis used the Framework Method and NVivo 12 to assist with generation and organisation of codes, inductive and deductive (Theoretical Domains Framework). The REMI.D project was a place-based approach (place in this case being defined as two local authorities with significant rates of deprivation) situated in the North East of England. Twenty patients out of a possible 65 patients took part. Areas of interest included: patient choice, patient intention, patient adherence, patient non-Adherence, and patient stigma. Addition of a more moderate dietary strategy (not dissimilar to the diet in the Healthier You NHS Diabetes Prevention Programme) to the existing NHS England T2D Path to Remission programme may enable more patients to achieve remission or delayed progression with deprescribing of diabetes medications. Embedding a tailored physical activity path within or as a bolt-on to the NHS programme requires consideration. Limited resources should be targeted towards patients who identify with more barriers or fewer opportunities for health behaviour modification. Further research on use of virtual programmes in deprived areas is warranted

Consumption of energy drinks by children and young people: a systematic review examining evidence of physical effects and consumer attitudes

ObjectiveTo update an earlier review, published in 2016, on the health and other outcomes associated with children and young people\u27s consumption of energy drinks (EDs).Study designReview article.Systematic reviewSystematic searches of nine databases (ASSIA, CINAHL, Cochrane Library, DARE, Embase, ERIC, MEDLINE, PsycINFO and Web of Science) retrieved original articles reporting the effects of EDs experienced by children and young people up to the age of 21 years. Searches were restricted by publication dates (January 2016 to July 2022) and language (English). Studies assessed as being weak were excluded from the review. Included studies underwent narrative synthesis.ResultsA total of 57 studies were included. Boys consumed EDs more than girls. Many studies reported a strong positive association between ED consumption and smoking, alcohol use, binge drinking, other substance use and the intentions to initiate these behaviours. Sensation-seeking and delinquent behaviours were positively associated with ED consumption, as were short sleep duration, poor sleep quality and low academic performance. Additional health effects noted in the updated review included increased risk of suicide, psychological distress, attention-deficit hyperactivity disorder symptoms, depressive and panic behaviours, allergic diseases, insulin resistance, dental caries and erosive tooth wear.ConclusionsThis review adds to the growing evidence that ED consumption by children and young people is associated with numerous adverse physical and mental health outcomes. Where feasible and ethical, additional longitudinal studies are required to ascertain causality. The precautionary principle should be considered in regulatory policy and restriction of ED sales to this population.PROSPERO registrationCRD42021255484

Examining the validity and utility of two secondary sources of food environment data against street audits in England

Background: Secondary data containing the locations of food outlets is increasingly used in nutrition and obesity research and policy. However, evidence evaluating these data is limited. This study validates two sources of secondary food environment data: Ordnance Survey Points of Interest data (POI) and food hygiene data from the Food Standards Agency (FSA), against street audits in England and appraises the utility of these data. Methods: Audits were conducted across 52 Lower Super Output Areas in England. All streets within each Lower Super Output Area were covered to identify the name and street address of all food outlets therein. Audit-identified outlets were matched to outlets in the POI and FSA data to identify true positives (TP: outlets in both the audits and the POI/FSA data), false positives (FP: outlets in the POI/FSA data only) and false negatives (FN: outlets in the audits only). Agreement was assessed using positive predictive values (PPV: TP/(TP+FP)) and sensitivities (TP/(TP+FN)). Variations in sensitivities and PPVs across environment and outlet types were assessed using multi-level logistic regression. Proprietary classifications within the POI data were additionally used to classify outlets, and agreement between audit-derived and POI-derived classifications was assessed. Results: Street audits identified 1172 outlets, compared to 1100 and 1082 for POI and FSA respectively. PPVs were statistically significantly higher for FSA (0.91, CI: 0.89-0.93) than for POI (0.86, CI: 0.84-0.88). However, sensitivity values were not different between the two datasets. Sensitivity and PPVs varied across outlet types for both datasets. Without accounting for this, POI had statistically significantly better PPVs in rural and affluent areas. After accounting for variability across outlet types, FSA had statistically significantly better sensitivity in rural areas and worse sensitivity in rural middle affluence areas (relative to deprived). Audit-derived and POI-derived classifications exhibited substantial agreement (p < 0.001; Kappa = 0.66, CI: 0.63 - 0.70). Conclusions: POI and FSA data have good agreement with street audits; although both datasets had geographic biases which may need to be accounted for in analyses. Use of POI proprietary classifications is an accurate method for classifying outlets, providing time savings compared to manual classification of outlets

Planning policies to restrict fast food and inequalities in child weight in England: a quasi-experimental analysis

\ua9 2024 The Author(s). Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society.Objective: England has one of the highest childhood obesity rates in Europe. To promote a healthier food environment in 2015, Gateshead Council in North East England introduced planning guidelines effectively banning any new fast-food outlets. Our aim was to investigate whether this policy led to any reductions in childhood overweight and obesity prevalence and the inequalities in these outcomes. Methods: We used data from the National Child Measurement Programme, the Food Standards Agency Food Hygiene Rating Scheme data, and the Office of National Statistics between 2012 and 2020. We estimated a difference-in-differences model employing propensity score matching to identify a control group. Results: We found no significant change in population-level childhood overweight and obesity in Gateshead compared with control areas. In subgroup analysis by area-level deprivation, we found that the quintile of deprivation with the highest proportion of fast-food outlets had a statistically significant reduction of 4.8% in the prevalence of childhood overweight and obesity compared with control areas. Conclusions: Restricting fast-food outlets in areas with a high concentration of such outlets as part of a package of policies to reduce childhood obesity may help to reduce prevalence and inequalities in childhood overweight and obesity

Change in maternal body mass index is associated with offspring body mass index: a 21-year prospective study

High body-mass index (BMI; defined as 25 kg/m(2) or greater) is associated with increased risk of cancer. To inform public health policy and future research, we estimated the global burden of cancer attributable to high BMI in 2012

Validation of food store environment secondary data source and the role of neighborhood deprivation in Appalachia, Kentucky

Background Based on the need for better measurement of the retail food environment in rural settings and to examine how deprivation may be unique in rural settings, the aims of this study were: 1) to validate one commercially available data source with direct field observations of food retailers; and 2) to examine the association between modified neighborhood deprivation and the modified retail food environment score (mRFEI). Methods Secondary data were obtained from a commercial database, InfoUSA in 2011, on all retail food outlets for each census tract. In 2011, direct observation identifying all listed food retailers was conducted in 14 counties in Kentucky. Sensitivity and positive predictive values (PPV) were compared. Neighborhood deprivation index was derived from American Community Survey data. Multinomial regression was used to examine associations between neighborhood deprivation and the mRFEI score (indicator of retailers selling healthy foods such as low-fat foods and fruits and vegetables relative to retailers selling more energy dense foods). Results The sensitivity of the commercial database was high for traditional food retailers (grocery stores, supermarkets, convenience stores), with a range of 0.96-1.00, but lower for non-traditional food retailers; dollar stores (0.20) and Farmer’s Markets (0.50). For traditional food outlets, the PPV for smaller non-chain grocery stores was 38%, and large chain supermarkets was 87%. Compared to those with no stores in their neighborhoods, those with a supercenter [OR 0.50 (95% CI 0.27. 0.97)] or convenience store [OR 0.67 (95% CI 0.51, 0.89)] in their neighborhood have lower odds of living in a low deprivation neighborhood relative to a high deprivation neighborhood. Conclusion The secondary commercial database used in this study was insufficient to characterize the rural retail food environment. Our findings suggest that neighborhoods with high neighborhood deprivation are associated with having certain store types that may promote less healthy food options