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Quantum gravitational corrections to a Kerr black hole using Topos theory
No full textWe examine non-perturbative quantum gravitational corrections to a Kerr black hole using Topos theory. Black hole thermodynamics is modeled using sheaves, and these corrections are represented as additional morphisms on these sheaves. These corrections are thus expressed as intrinsic structural modifications modeled by these new morphisms, allowing both the original and quantum gravitationally corrected structures to exist within the same Topos. We also construct a functor between thermodynamics and information theory by using the Parikh- Wilczek formalism to represent the probability density of emitted particles as sheaves. Then, using the Kullback-Leibler divergence as another functor, we measure deviations of the quantum gravitationally corrected sheaves from the original sheaves. To obtain information about the modifications produced by quantum gravity, we construct an additional functor representing Fisher information. Topos theory provides a formalism that allowing us to study properties of the system in classical spacetime as well as cases where the classical spacetime breaks down near the Planck scale. This formulation reveals a novel information paradox in the ultraviolet regime of quantum gravity, where not only does information about particle states become inaccessible, but even information about the quantum gravitational modifications themselves becomes computationally unobtainable.COST, Actions [CA21106, CA22113
Association of Technology-Related Skills and Self-Efficacy With Willingness to Participate in Heart Failure Telemonitoring: Cross-Sectional Observational Study
No full textBackground: The adoption of telemonitoring in patients with heart failure (HF) is influenced by technology-related skills and self-efficacy, as well as psychological, clinical, and demographic factors. However, the relative importance of these factors with regard to willingness to use telemonitoring is insufficiently understood. Objectives: This cross-sectional observational study examines the extent to which technology-related skills and self-efficacy are related to willingness to participate in telemonitoring in patients with HF. Methods: Patients completed questionnaires during hospitalization. Associations of technological skills and self-efficacy with willingness to participate in telemonitoring (dichotomous and continuous scale) were examined using regression models. Mediation-moderation analyses were used to investigate the role of self-efficacy in the association of technological skills with willingness to participate. Results: This study recruited 61 patients admitted for decompensated HF (mean age 79.9, SD 9.5 years; 24 women). Higher levels of technological skills were associated with higher willingness to participate in telemonitoring (odds ratio [OR] 1.073 per scale unit, 95% CI 1.031-1.117). Technological self-efficacy and learnability were also related to willingness to participate (OR 1.141, 95% CI 1.039-1.252; OR 1.029, 95% CI 1.006-1.052) but did not mediate the association of technological skills with willingness to participate in telemonitoring. Psychological factors (anxiety, depressive symptoms, and perceived social support), age, and cognitive and physical functioning did not moderate the association of technological skills with willingness to participate in telemonitoring. Conclusions: Technological skills, self-efficacy, and learnability are interrelated factors that need to be considered in patients with HF who are eligible for telemonitoring. Future intervention studies that target these factors could increase patients' willingness and competence in using telemonitoring after admission for HF
Biomorphoelasticity alone: limitations in modeling post-burn contraction and hypertrophy without finite strains
No full textWe present a continuum hypothesis-based two-dimensional biomorphoelastic model describing post-burn scar hypertrophy and contraction. The model is based on morphoelasticity for permanent deformations and combined with a chemical-biological model that incorporates cellular densities, collagen density, and the concentration of chemoattractants. We perform a sensitivity analysis for the independent parameters of the model and focus on the effects on the features of the post-burn dermal thickness given a low myofibroblast apoptosis rate. We conclude that the most sensitive parameters are the equilibrium collagen concentration, the signaling molecule secretion rate and the cell force constant, and link these results to stability constraints. Next, we observe a relationship between the simulated contraction and hypertrophy and show the effects for significant variations in the myofibroblast apoptosis rate (high/low). Our ultimate goal is to optimize post-burn treatments, by developing models that predict with a high degree of certainty. We consider the presented model and sensitivity analysis to be a step toward their construction.The authors are grateful for the fnancial support
from the Dutch Burns Foundation under projects 17.105 and 22.10
Screening for gonorrhoea and chlamydia: identifying key target populations and intensity-a modelling study of MSM in Belgium
No full textBackground Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are two of the most common bacterial sexually transmitted infections (STIs) among men who have sex with men (MSM). Screening for CT and NG has been promoted as an intervention to reduce the prevalence of these STIs. We aimed to evaluate the effect of different screening intensities on the prevalence of CT, NG and the emergence of azithromycin-resistant NG (AR-NG) in an MSM population.Methods We developed a network-based model for CT and NG transmission among MSM in Belgium to estimate the prevalence of CT, NG and AR-NG in the population. The model simulates transmission of CT/NG among three anatomical sites in a population of 10 000 MSM, divided into high-activity and low-activity groups, over 10 years. The effect of different screening frequencies and coverage was evaluated in terms of CT, NG and AR-NG prevalence.Results Gonorrhoea prevalence ranged between 12% and 16% in scenarios screening 0-80% of the population. Screening among the low-activity MSM (LA-MSM) group had little effect on NG prevalence but increased the risk of AR-NG. Infrequent screening (less than every 180 days) with high coverage (over 40%) resulted in the highest risk for the spread of AR-NG in the population. Screening up to 40% of low-activity (HA-MSM) every 90 days and up to 20% of LA-MSM reduced NG prevalence to 14% without selecting for AMR. Screening coverage and frequency had little impact on CT prevalence in all scenarios.Conclusions Our model suggests that NG/CT screening has a modest effect in controlling the prevalence of these infections in the MSM population in Belgium. Screening efforts should move away from LA-MSM. Screening alone would not be sufficient to control the CT/NG epidemic, and future models should incorporate the impact of additional interventions such as vaccination and doxycycline post-exposure prophylaxis.This study was funded by Fonds Wetenschappelijk Onderzoek (12B1M24N)
Temporal Trend and Regional Disparity in the Investigations for Stable Chest Pain in Europe: An Insight From the PIONEER IV Trial
No full textDe LULUCF-verordening: een onderbenutte hefboom in de strijd tegen klimaatverandering
No full textDe LULUCF-verordening is een van de centrale instrumenten in het klimaatbeleid van de Europese Unie. Deze verordening focust op broeikasgasemissies en-verwijderingen binnen de landgebruik-en bosbouwsector. Grosso modo legt ze lidstaten de verplichting op om (i) tegen 2025 alle emissies binnen de LULUCF-sector te compenseren met verwijderingen (no debit) en (ii) tegen 2030 een overeengekomen hoeveelheid CO-equivalent emissies te verwijderen. Uit recente gegevens blijkt dat de EU niet op schema zit om deze 2030-doelstelling te halen. Ook de Belgische LULUCF-sector zal een tandje moeten bijsteken. Tegelijkertijd zijn er op EU-niveau de laatste jaren verschillende wetgevende initiatieven genomen, zoals het EU-certificeringskader voor koolstofverwijderingen en de Natuurherstelwet, die erop gericht zijn de LULUCF-sector te versterken. Het is nog afwachten in welke mate deze initiatieven effectief een bijdrage zullen kunnen leveren. In ieder geval is een inhaalbeweging noodzakelijk, want inmiddels zijn er in de EU al verschillende rechtszaken aanhangig gemaakt die betrekking hebben op het LULUCF-beleid en ook over de impact van dit beleid op de vergunningverlening is het laatste woord nog niet gezegd.Met dank aan het Bijzonder Onderzoeksfonds van de UHasselt voor de financiering in het kader van het onderzoeksproject ‘De LULUCF-
verordening: een onderzoek naar de praktische toepassing van de LULUCF-verordening met behulp van rechtsvergelijkende
analyses’ (2023-2027) (doctoraal onderzoek; promotor prof. dr. Carole M. BILLIET).
Met dank aan de steun van de Nationale Loterij. Dankzij de spelers kon de Nationale Loterij het project “Naar een optimaal herstel van
de Belgische natuur tegen 2050”, m.i.v. deze bijdrage, ondersteunen
Contact patterns of older adults with and without frailty in the Netherlands during the COVID-19 pandemic
No full textBackgroundDuring the COVID-19 pandemic, social distancing measures were imposed to protect the population from exposure, especially older adults and people with frailty, who have the highest risk for severe outcomes. These restrictions greatly reduced contacts in the general population, but little was known about behaviour changes among older adults and people with frailty themselves. Our aim was to quantify how COVID-19 measures affected the contact behaviour of older adults and how this differed between older adults with and without frailty.MethodsIn 2021, a contact survey was carried out among people aged 70 years and older in the Netherlands. A random sample of persons per age group (70-74, 75-79, 80-84, 85-89, and 90 +) and gender was invited to participate, either during a period with stringent (April 2021) or moderate (October 2021) measures. Participants provided general information on themselves, including their frailty, and they reported characteristics of all persons with whom they had face-to-face contact on a given day over the course of a full week.ResultsIn total, 720 community-dwelling older adults were included (overall response rate of 15%), who reported 16,505 contacts. During the survey period with moderate measures, participants without frailty had significantly more contacts outside their household than participants with frailty. Especially for females, frailty was a more informative predictor of the number of contacts than age. During the survey period with stringent measures, participants with and without frailty had significantly lower numbers of contacts compared to the survey period with moderate measures. The reduction of the number of contacts was largest for the eldest participants without frailty. As they interact mostly with adults of a similar high age who are likely frail, this reduction of the number of contacts indirectly protects older adults with frailty from SARS-CoV-2 exposure.ConclusionsThe results of this study reveal that social distancing measures during the COVID-19 pandemic differentially affected the contact patterns of older adults with and without frailty. The reduction of contacts may have led to the direct protection of older adults in general but also to the indirect protection of older adults with frailty.Funding
The SCONE study was fnanced by the Netherlands Organisation for Health Research and Development (ZonMw; grant number 10150511910020).
Acknowledgements
The authors would like to thank all participants of the SCONE (Studying Contacts of Elderly) study for their invaluable input, Inge Besemer for processing the data, and Kylie Ainslie and Brechje de Gier for critically reading the manuscript