Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

Eating disorders in weight-related therapy (EDIT): Protocol for a systematic review with individual participant data meta-analysis of eating disorder risk in behavioural weight management

The Eating Disorders In weight-related Therapy (EDIT) Collaboration brings together data from randomised controlled trials of behavioural weight management interventions to identify individual participant risk factors and intervention strategies that contribute to eating disorder risk. We present a protocol for a systematic review and individual participant data (IPD) meta-analysis which aims to identify participants at risk of developing eating disorders, or related symptoms, during or after weight management interventions conducted in adolescents or adults with overweight or obesity. We systematically searched four databases up to March 2022 and clinical trials registries to May 2022 to identify randomised controlled trials of weight management interventions conducted in adolescents or adults with overweight or obesity that measured eating disorder risk at pre- and post-intervention or follow-up. Authors from eligible trials have been invited to share their deidentified IPD. Two IPD meta-analyses will be conducted. The first IPD meta-analysis aims to examine participant level factors associated with a change in eating disorder scores during and following a weight management intervention. To do this we will examine baseline variables that predict change in eating disorder risk within intervention arms. The second IPD meta-analysis aims to assess whether there are participant level factors that predict whether participation in an intervention is more or less likely than no intervention to lead to a change in eating disorder risk. To do this, we will examine if there are differences in predictors of eating disorder risk between intervention and no-treatment control arms. The primary outcome will be a standardised mean difference in global eating disorder score from baseline to immediately post-intervention and at 6- and 12- months follow-up. Identifying participant level risk factors predicting eating disorder risk will inform screening and monitoring protocols to allow early identification and intervention for those at risk

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

SARS-CoV-2-specific nasal IgA wanes 9 months after hospitalisation with COVID-19 and is not induced by subsequent vaccination

BACKGROUND: Most studies of immunity to SARS-CoV-2 focus on circulating antibody, giving limited insights into mucosal defences that prevent viral replication and onward transmission. We studied nasal and plasma antibody responses one year after hospitalisation for COVID-19, including a period when SARS-CoV-2 vaccination was introduced. METHODS: In this follow up study, plasma and nasosorption samples were prospectively collected from 446 adults hospitalised for COVID-19 between February 2020 and March 2021 via the ISARIC4C and PHOSP-COVID consortia. IgA and IgG responses to NP and S of ancestral SARS-CoV-2, Delta and Omicron (BA.1) variants were measured by electrochemiluminescence and compared with plasma neutralisation data. FINDINGS: Strong and consistent nasal anti-NP and anti-S IgA responses were demonstrated, which remained elevated for nine months (p < 0.0001). Nasal and plasma anti-S IgG remained elevated for at least 12 months (p < 0.0001) with plasma neutralising titres that were raised against all variants compared to controls (p < 0.0001). Of 323 with complete data, 307 were vaccinated between 6 and 12 months; coinciding with rises in nasal and plasma IgA and IgG anti-S titres for all SARS-CoV-2 variants, although the change in nasal IgA was minimal (1.46-fold change after 10 months, p = 0.011) and the median remained below the positive threshold determined by pre-pandemic controls. Samples 12 months after admission showed no association between nasal IgA and plasma IgG anti-S responses (R = 0.05, p = 0.18), indicating that nasal IgA responses are distinct from those in plasma and minimally boosted by vaccination. INTERPRETATION: The decline in nasal IgA responses 9 months after infection and minimal impact of subsequent vaccination may explain the lack of long-lasting nasal defence against reinfection and the limited effects of vaccination on transmission. These findings highlight the need to develop vaccines that enhance nasal immunity. FUNDING: This study has been supported by ISARIC4C and PHOSP-COVID consortia. ISARIC4C is supported by grants from the National Institute for Health and Care Research and the Medical Research Council. Liverpool Experimental Cancer Medicine Centre provided infrastructure support for this research. The PHOSP-COVD study is jointly funded by UK Research and Innovation and National Institute of Health and Care Research. The funders were not involved in the study design, interpretation of data or the writing of this manuscript

Acoustic information about upper limb movement in voicing

Contains fulltext : 219006.pdf (Publisher’s version ) (Open Access)We show that the human voice carries an acoustic signature of muscle tensioning during upper limb movements which can be detected by listeners. Specifically, we find that human listeners can synchronize their own movements to very subtle wrist movements of a vocalizer only by listening to their vocalizations and without any visual contact. This study shows that the human voice contains information about dynamic bodily states, breaking ground for our understanding of the evolution of spoken language and nonverbal communication. The current findings are in line with other research on nonhuman animals, showing that vocalizations carry information about bodily states and capacities.We show that the human voice has complex acoustic qualities that are directly coupled to peripheral musculoskeletal tensioning of the body, such as subtle wrist movements. In this study, human vocalizers produced a steady-state vocalization while rhythmically moving the wrist or the arm at different tempos. Although listeners could only hear and not see the vocalizer, they were able to completely synchronize their own rhythmic wrist or arm movement with the movement of the vocalizer which they perceived in the voice acoustics. This study corroborates recent evidence suggesting that the human voice is constrained by bodily tensioning affecting the respiratory-vocal system. The current results show that the human voice contains a bodily imprint that is directly informative for the interpersonal perception of another’s dynamic physical states.4 p

Acoustic specification of upper limb movement in voicing

Hand gestures communicate through the visual information created by movement. Recently,we found that there are also direct biomechanical effects of high-impetus upper limb movementon voice acoustics. Here we explored whether listeners could detect information aboutmovement in the voicing of another person. In this exploratory study, participants listened to arecorded vocalizer who was simultaneously producing low-(wrist movement) or high-(armmovement) impetus movements at three different tempos. Listeners were asked to synchronizetheir own movement (wrist or arm movement) with the vocalizer. Listeners coupled with thefrequency of the vocalizer arm (but not wrist) movements, and showed phase-coupling withvocalizer arm (but not wrist) movements. However, we found that this synchronizationoccurred regardless of whether the listener was moving their wrist or arm. This study showsthat, in principle, there is acoustic specification of arm movements in voicing, but not wristmovements. These results, if replicated, provide novel insight into the possible interpersonalfunctions of gesture acoustics, which may lie in communicating bodily states.Wim Pouw, Alexandra Paxton, Steven J. Harrison, and James A. Dixo

Better psychological health is associated with weight stability in women with eating disorders

To explore the associations between changes in weight, eating disorder psychopathology and psychological distress in a community sample of women with eating disorders over two years. METHOD: One hundred and twenty two women identified with disordered eating in a baseline population survey agreed to participate in a follow-up study, of whom 87 (71%), mean age 28±6.2, completed the two-year follow-up. Body mass index, eating disorder psychopathology, psychological distress, and demographic details were assessed at both time points. RESULTS: Over the two years there was a mean weight gain of 1.76 kg (SD=7.03), 11 (13%) women lost ≥5 kg, 25 (29%) gained ≥5 kg, and 49 (58%) remained weight stable (i.e., within 5 kg of baseline weight). Comparisons between those who had lost, gained and remained weight stable showed few significant differences, however, women who remained weight stable were the least psychologically distressed at baseline and those who lost weight had the greatest reduction in shape concern. Body mass index at baseline, and change in level of binge eating episodes were not associated with weight change. CONCLUSIONS: Disordered eating behaviours have little influence on weight change over two years in community women with disordered eating. Low levels of psychological distress at baseline may promote weight stability. Concerns about shape are likely to increase with increased weight

Women with bulimic eating disorders: when do they receive treatment for an eating problem?

Variables associated with the use of health services were examined in a prospective, community-based study of women with bulimic-type eating disorders who did (n = 33) or did not (n = 58) receive treatment for an eating problem during a 12-month follow-up period. Participants who received treatment for an eating problem differed from those who did not in several respects, including higher body weight, higher levels of eating disorder psychopathology, general psychological distress, and impairment in role functioning, deficits in specific aspects of coping style, greater awareness of an eating problem, and greater likelihood of prior treatment for a problem with weight. However, the variables most strongly associated with treatment seeking were greater perceived impairment in role functioning specifically associated with an eating problem and greater perceived inability to suppress emotional difficulties. These were the only variables that were significantly associated with treatment seeking in multivariable analysis. The findings suggest that individuals’ recognition of the adverse effects of eating-disordered behavior on quality of life may need to be addressed in prevention and early intervention programs for eating disorders