Resonance bifurcations from robust homoclinic cycles

We present two calculations for a class of robust homoclinic cycles with symmetry Z_n x Z_2^n, for which the sufficient conditions for asymptotic stability given by Krupa and Melbourne are not optimal. Firstly, we compute optimal conditions for asymptotic stability using transition matrix techniques which make explicit use of the geometry of the group action. Secondly, through an explicit computation of the global parts of the Poincare map near the cycle we show that, generically, the resonance bifurcations from the cycles are supercritical: a unique branch of asymptotically stable period orbits emerges from the resonance bifurcation and exists for coefficient values where the cycle has lost stability. This calculation is the first to explicitly compute the criticality of a resonance bifurcation, and answers a conjecture of Field and Swift in a particular limiting case. Moreover, we are able to obtain an asymptotically-correct analytic expression for the period of the bifurcating orbit, with no adjustable parameters, which has not proved possible previously. We show that the asymptotic analysis compares very favourably with numerical results.Comment: 24 pages, 3 figures, submitted to Nonlinearit

Do sleep difficulties exacerbate deficits in sustained attention following traumatic brain injury?

Sustained attention has been shown to be vulnerable following traumatic brain injury (TBI). Sleep restriction and disturbances have been shown to negatively affect sustained attention. Sleep disorders are common but under-diagnosed after TBI. Thus, it seems possible that sleep disturbances may exacerbate neuropsychological deficits for a proportion of individuals who have sustained a TBI. The aim of this prospective study was to examine whether poor sleepers post-TBI had poorer sustained and general attentional functioning than good sleepers post-TBI. Retrospective subjective, prospective subjective, and objective measures were used to assess participants’ sleep. The results showed that the poor sleep group had significantly poorer sustained attention ability than the good sleep group. The differences on other measures of attention were not significant. This study supports the use of measures that capture specific components of attention rather than global measures of attention, and highlights the importance of assessing and treating sleep problems in brain injury rehabilitation

Unrelated Helpers in a Primitively Eusocial Wasp: Is Helping Tailored Towards Direct Fitness?

The paper wasp Polistes dominulus is unique among the social insects in that nearly one-third of co-foundresses are completely unrelated to the dominant individual whose offspring they help to rear and yet reproductive skew is high. These unrelated subordinates stand to gain direct fitness through nest inheritance, raising the question of whether their behaviour is adaptively tailored towards maximizing inheritance prospects. Unusually, in this species, a wealth of theory and empirical data allows us to predict how unrelated subordinates should behave. Based on these predictions, here we compare helping in subordinates that are unrelated or related to the dominant wasp across an extensive range of field-based behavioural contexts. We find no differences in foraging effort, defense behaviour, aggression or inheritance rank between unrelated helpers and their related counterparts. Our study provides no evidence, across a number of behavioural scenarios, that the behaviour of unrelated subordinates is adaptively modified to promote direct fitness interests

Ecological selectivity and the evolution of mammalian substrate preference across the K-Pg boundary.

The Cretaceous-Paleogene (K-Pg) mass extinction 66 million years ago was characterized by a worldwide ecological catastrophe and rapid species turnover. Large-scale devastation of forested environments resulting from the Chicxulub asteroid impact likely influenced the evolutionary trajectories of multiple clades in terrestrial environments, and it has been hypothesized to have biased survivorship in favour of nonarboreal lineages across the K-Pg boundary. Here, we evaluate patterns of substrate preferences across the K-Pg boundary among crown group mammals, a group that underwent rapid diversification following the mass extinction. Using Bayesian, likelihood, and parsimony reconstructions, we identify patterns of mammalian ecological selectivity that are broadly similar to those previously hypothesized for birds. Models based on extant taxa indicate predominant K-Pg survivorship among semi- or nonarboreal taxa, followed by numerous independent transitions to arboreality in the early Cenozoic. However, contrary to the predominant signal, some or all members of total-clade Euarchonta (Primates + Dermoptera + Scandentia) appear to have maintained arboreal habits across the K-Pg boundary, suggesting ecological flexibility during an interval of global habitat instability. We further observe a pronounced shift in character state transitions away from plesiomorphic arboreality associated with the K-Pg transition. Our findings are consistent with the hypothesis that predominantly nonarboreal taxa preferentially survived the end-Cretaceous mass extinction, and emphasize the pivotal influence of the K-Pg transition in shaping the early evolutionary trajectories of extant terrestrial vertebrates.NS

Re‐defining the virtual reality dental simulator: Demonstrating concurrent validity of clinically relevant assessment and feedback

Introduction Virtual reality (VR) dental simulators are gaining momentum as a useful tool to educate dental students. To date, no VR dental simulator exercise has been designed which is capable of reliably providing validated, meaningful clinical feedback to dental students. This study aims to measure the concurrent validity of the assessment, and the provision of qualitative feedback, pertaining to cavity preparations by VR dental simulators. Methods A cavity preparation exercise was created on a VR dental simulator, and assessment criteria for cavity preparations were developed. The exercise was performed 10 times in order to demonstrate a range of performances and for each, the simulator feedback was recorded. The exercises were subsequently three‐dimensionally printed and 12 clinical teachers were asked to assess the preparations according to the same criteria. Inter‐rater reliability (IRR) between clinical teachers was measured using a free‐marginal multirater kappa value. Clinical teacher assessment responses were compared with the VR simulator responses and percentage agreements calculated. Results IRR values for each exercise ranged from 0.39‐0.77 (69.39‐88.48%). The assessment of smoothness (κfree0.58, 78.79%) and ability to follow the outline (κfree0.56, 77.88%) demonstrated highest agreement between clinical teachers, whilst the assessment of undercut (κfree0.15, 57.58%) and depth (κfree 0.28, 64.09%) had the lowest agreement. The modal percentage agreement between clinical teachers and the VR simulator was, on average, 78% across all exercises. Conclusion The results of this study demonstrate that it is possible to provide reliable and clinically relevant qualitative feedback via a VR dental simulator. Further research should look to employ this technique across a broader range of exercises that help to develop other complex operative dental skills

A qualitative analysis of free‑text patient satisfaction responses in Care Response, a database of patient‑reported outcome and experience measures

Background: Databases have become important tools in improving health care. Care Response is a database containing information on tens of thousands of chiropractic patients internationally. It has been collecting patient-reported outcomes and patient satisfaction information for more than 10 years. The purpose of this study was to contribute to the understanding of patient perceptions and priorities for chiropractic care by analysing free text entered into the patient reported experience measure (PREM) questionnaires within the Care Response system. Methods: There were two questions of interest on the PREM for this study. One requested information about “good points” patients perceived about patients’ care experience, and the other requested information on “improvements” that could make the experience better. We conducted a word frequency analysis using a word counting macro in Microsoft Word, then used those results as a starting point for a qualitative analysis. Data were collected on 30 May 2022. Results: The people who participated in the Care Response system often reported positive experiences with their chiropractors, including that they had reduced pain, improved function, and felt validated in their clinical condition. In addition, they appreciated having diagnostic and treatment procedures explained to them. They valued friendly, professional, and on-time service. The negative experiences were the opposite: being rushed through treatment, that the treatment was not worth the cost, or that they weren’t treated professionally, empathetically, or with respect for them as individuals. The most important themes that emerged under “good points” were satisfaction (with care), value (as a person), safety, comfort, and professionalism. Their opposites, dissatisfaction, lack of value, lack of safety, lack of comfort, and lack of professionalism emerged as the most important themes under “improvements”. We report some nuances of patient experience that have not previously been explored in the literature. Conclusions: Respondents seemed to value effective care provided in a safe, professional, friendly, and aesthetically pleasing environment. Chiropractors should note these priorities and engage with patients according to them. Education institutions should consider how good practice in these areas might be incorporated into curricula

Structurally diverse hamigerans from the New Zealand marine sponge Hamigera tarangaensis: NMR-directed isolation, structure elucidation and antifungal activity

The NMR-directed investigation of the New Zealand marine sponge Hamigera tarangaensis has afforded ten new compounds of the hamigeran family, and a new 13-epi-verrucosane congener. Notably, hamigeran F (6) possesses an unusual carbon–carbon bond between C-12 and C-13, creating an unprecedented skeleton within this class. In particular, the structural features of 6, hamigeran H (10) and hamigeran J (12) imply a diterpenoid origin, which has allowed the putative biogenesis of three hamigeran carbon skeletons to be proposed based on geranyl geranyl pyrophosphate. All new hamigerans exhibited micromolar activity towards the HL-60 promyelocytic leukaemic cell line, and hamigeran G also selectively displayed antifungal activity in the budding yeast Saccharomyces cerevisiae. Homozygous deletion profiling (HOP) analysis suggests Golgi apparatus function as a potential target of this unusual class of sponge-derived terpenoids

Hyb:A bioinformatics pipeline for the analysis of CLASH (crosslinking, ligation and sequencing of hybrids) data

Peer reviewedPublisher PD

Isotropically Driven versus Outflow Driven Turbulence: Observational Consequences for Molecular Clouds

Feedback from protostellar outflows can influence the nature of turbulence in star forming regions even if they are not the primary source of velocity dispersion for all scales of molecular clouds. For the rate and power expected in star forming regions, we previously (Carroll et al. 2009) demonstrated that outflows could drive supersonic turbulence at levels consistent with the scaling relations from Matzner 2007 although with a steeper velocity power spectrum than expected for an isotropically driven supersonic turbulent cascade. Here we perform higher resolution simulations and combine simulations of outflow driven turbulence with those of isotropically forced turbulence. We find that the presence of outflows within an ambient isotropically driven turbulent environment produces a knee in the velocity power spectrum at the outflow scale and a steeper slope at sub-outflow scales than for a purely isotropically forced case. We also find that the presence of outflows flattens the density spectrum at large scales effectively reducing the formation of large scale turbulent density structures. These effects are qualitatively independent of resolution. We have also carried out Principal Component Analysis (PCA) for synthetic data from our simulations. We find that PCA as a tool for identifying the driving scale of turbulence has a misleading bias toward low amplitude large scale velocity structures even when they are not necessarily the dominant energy containing scales. This bias is absent for isotropically forced turbulence but manifests strongly for collimated outflow driven turbulence.Comment: 30 pages, 10 figures, Submitted to Ap

A descriptive analysis of the contents of Care Response, an international data set of patient-reported outcomes for chiropractic patients

Background: Databases have become an important tool in understanding trends and correlations in health care by collecting demographic and clinical information. Analysis of data collected from large cohorts of patients can have the potential to generate insights into factors identifying treatments and the characteristics of subgroups of patients who respond to certain types of care. The Care Response (CR) database was designed to capture patient-reported outcome measures (PROMs) for chiropractic patients internationally. Although several papers have been published analysing some of the data, its contents have not yet been comprehensively documented. The primary aim of this study was to describe the information in the CR database. The secondary aim was to determine whether there was suitable information available to better understand subgroups of chiropractic patients and responsiveness to care. This would be achieved by enabling correlations among patient demographics, diagnoses, and therapeutic interventions with machine learning approaches. Methods: Data in all available fields were requested with no date restriction. Data were collected on 12 April 2022. The output was manually scanned for scope and completeness. Tables were created with categories of information. Descriptive statistics were applied. Results: The CR database collects information from patients at the first clinical visit, 14, 30, and 90 days subsequently. There were 32,468 patient responses; 3210 patients completed all fields through the 90 day follow up period. 45% of respondents were male; 54% were female; the average age was 49. There was little demographic information, and no information on diagnoses or therapeutic interventions. We received StartBack, numerical pain scale, patient global impression of change, and Bournemouth questionnaire data, but no other PROMs. Conclusions: The CR database is a large set of PROMs for chiropractic patients internationally. We found it unsuitable for machine learning analysis for our purposes; its utility is limited by a lack of demographic information, diagnoses, and therapeutic interventions. However, it can offer information about chiropractic care in general and patient satisfaction. It could form the basis for a useful clinical tool in the future, if reformed to be more accessible to researchers and expanded with more information collected