The formation of shocks within the solar atmosphere remains one of the few observable signatures of energy dissipation arising from the plethora of magnetohydrodynamic waves generated close to the solar surface. Active region observations offer exceptional views of wave behavior and its impact on the surrounding atmosphere. The stratified plasma gradients present in the lower solar atmosphere allow for the potential formation of many theorized shock phenomena. In this study, using chromospheric Ca ii λ8542 line spectropolarimetric data of a large sunspot, we examine fluctuations in the plasma parameters in the aftermath of powerful shock events that demonstrate polarimetric reversals during their evolution. Modern inversion techniques are employed to uncover perturbations in the temperatures, line-of-sight velocities, and vector magnetic fields occurring across a range of optical depths synonymous with the shock formation. Classification of these nonlinear signatures is carried out by comparing the observationally derived slow, fast, and Alfvén shock solutions with the theoretical Rankine–Hugoniot relations. Employing over 200,000 independent measurements, we reveal that the Alfvén (intermediate) shock solution provides the closest match between theory and observations at optical depths of log 10 τ = − 4 , consistent with a geometric height at the boundary between the upper photosphere and lower chromosphere. This work uncovers first-time evidence of the manifestation of chromospheric intermediate shocks in sunspot umbrae, providing a new method for the potential thermalization of wave energy in a range of magnetic structures, including pores, magnetic flux ropes, and magnetic bright points.

Background: Studies based on molecular testing of oral/nasal swabs underestimate SARS-CoV-2 infection due to issues with test sensitivity and timing of testing. The objective of this study was to report the presence of SARS-CoV-2 antibodies, consistent with previous infection, and to report the symptomatology of infection in children. Design: This multicentre observational cohort study, conducted between 16 ^th April – 3 ^rd July 2020 at 5 UK sites, aimed to recruit 900 children aged 2 to 15 years of age. Participants provided blood samples for SARS-CoV-2 antibody testing and data were gathered regarding unwell contacts and symptoms. Results: 1007 participants were enrolled, and 992 were included in the final analysis. The median age of participants was 10·1 years. There were 68 (6.9%) participants with positive SARS-CoV-2 antibody tests indicative of previous SARS-CoV-2 infection. Of these, 34/68 (50%) reported no symptoms. The presence of antibodies and the mean antibody titre was not influenced by age. Following multivariate analysis 4 independent variables were identified as significantly associated with SARS-CoV-2 infection. These were: known infected household contact; fatigue; gastrointestinal symptoms; and changes in sense of smell or taste. Discussion: In this study children demonstrated similar antibody titres in response to SARS-CoV-2 irrespective of age. The symptoms of SARS-CoV-2 infection in children were subtle but of those reported, fatigue, gastrointestinal symptoms and changes in sense of smell or taste were most strongly associated with antibody positivity. Registration: This study was registered at https://www.clinicaltrials.gov (trial registration: NCT04347408 ) on the 15/04/2020.

The Coxian phase-type distribution is a special type of Markov model which can be utilised both to uncover underlying stages of a survival process and to make inferences regarding the rates of flow of individuals through these latent stages before an event of interest occurs. Such models can be utilised, for example, to identify individuals who are likely to deteriorate faster through a series of disease states and thus require more aggressive medical intervention. Within this paper, a two-stage approach to the analysis of longitudinal and survival data is presented. In Stage 1, a linear mixed effects model is first used to represent how some longitudinal response of interest changes through time. Within this linear mixed effects model, the individuals’ random effects can be considered as a proxy measure for the effect of the individuals’ genetic profiles on the response of interest. In Stage 2, the Coxian phase-type distribution is employed to represent the survival process. The individuals’ random effects, estimated in Stage 1, are incorporated as covariates within the Coxian phase-type distribution so as to evaluate their effect on the individuals’ rates of flow through the system represented by the Coxian. The approach is illustrated using data collected on individuals suffering from chronic kidney disease, where focus is given to an emerging longitudinal biomarker of interest – an individual’s haemoglobin level.

Introduction: Febrile infants under 3 months of age are at risk of invasive bacterial infection (IBI). It is currently unclear if testing for respiratory viruses may have a role in IBI risk stratification. If found to be associated with the likelihood of IBI, respiratory viral point-of-care testing may improve patient and caregiver experience, reduce costs and enhance antimicrobial stewardship.Methods and analysis: This is a study protocol for a systematic review and meta-analysis that aims to answer the following question:In young febrile infants presenting to emergency care settings does a positive respiratory viral test for RSV, Influenza or SARS-CoV2 (relative to a negative test) add value to current risk stratification pathways for the exclusion of invasive bacterial infection, subsequently enabling safe de-escalation of investigation and treatment?A search strategy will include MEDLINE, EMBASE, Web of Science, The Cochrane Library and grey literature. Abstracts and then full texts will be independently screened for selection. Data extraction and quality assessment will be completed by two independent authors.The primary objective is to analyse the ability of a positive respiratory viral test to identify the overall risk of IBI. The secondary objective is to perform a subgroup analysis to investigate how the risk stratification alters based on other variables including virus type, patient characteristics and the presence of an identified source of fever.Bivariate random-effects meta-analysis will be undertaken. Diagnostic odds ratios (OR), sensitivity, specificity and positive and negative likelihood ratios will be calculated. The degree of heterogeneity and publication bias will be investigated and presented.Ethics and dissemination: Ethical approval is not required. We will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to disseminate the study results through publication and conference presentations.PROSPERO registration number: This protocol is registered in PROSPERO—ID number: CRD42023433716.

Background: Effective leadership is critical in driving and motivating registered nurses to provide high‐quality patient care. A link between effective transformational leadership (TL) in nursing and improved patient care outcomes has been established, but it is unknown how this association is affected. Aim: To examine the relationships between TL, structural empowerment (SE), registered nurses’ clinical leadership (CLS) and patient care outcomes. Methods: This quantitative cross‐sectional study was conducted in a government tertiary hospital in Saudi Arabia, with 1038 registered nurses clustered under 28 head nurses. Instruments used included the Multifactor Leadership Questionnaire, Conditions of Work Effectiveness Questionnaire II, clinical leadership survey and self‐reported measures of patient adverse events (AEs) and nursing care quality. Data were analysed using SPSS Version 28 and the R 4.3.3 packages ‘lavaan’, ‘semPlot’ and ‘semTools’ for multilevel structural equation modelling (MSEM). Results: Six hundred and sixty‐four surveys (response rate = 70%) were analysed. Multilevel analysis showed a significant positive association between TL and SE ( β = 0.56, p < 0.001) and SE and registered nurses’ clinical leadership ( β = 0.52, p < 0.001). Registered nurses’ clinical leadership was positively associated with quality of care ( β = 0.32, p < 0.001) and negatively associated with AEs ( β = −0.15, p < 0.001). Mediation analysis indicated a significant indirect effect of TL on registered nurses’ clinical leadership through SE ( B = 0.344, p < 0.001). SE was also indirectly associated with patient AEs through registered nurses’ clinical leadership ( B = −0.037, p = 0.003) and quality of nursing care (QOC) through registered nurses’ clinical leadership ( B = 0.147, p < 0.001). Conclusions: The study highlights the critical role that SE and nurses’ clinical leadership play in explaining how TL is associated with improved patient care. These findings provide evidence to support policy and training initiatives that develop leadership frameworks, ensuring a more empowered and effective nursing workforce capable of delivering high‐quality patient care.