151398 research outputs found
Sort by
Spectral efficiency analysis of near-field holographic MIMO over Ricean fading channels
No full textThe core idea of holographic MIMO (HMIMO) is to densely deploy numerous antenna elements within a given aperture size. However, with the denser distribution of antenna elements, stronger mutual coupling effects would kick in among antenna elements, which would eventually affect the communication performance. Meanwhile, as the holographic array usually has large physical size, the possibility of near-field communication increases. This paper investigates a near-field multi-user downlink HMIMO system and characterizes the spectral efficiency (SE) under the mutual coupling effect over Ricean fading channels. Both perfect and imperfect channel state information (CSI) scenarios are considered. (i) For the perfect CSI case, the mutual coupling and radiation efficiency model are first established. Then, a closed-form SE expression is derived under maximum ratio transmission (MRT). By comparing the SE between the cases with and without mutual coupling, it is unveiled that the system SE with mutual coupling might outperform that without mutual coupling in the low transmit power regime for a given aperture size. Moreover, it is also unveiled that the inter-user interference cannot be eliminated unless the physical size of the array increases to infinity. Fortunately, the additional distance term in the near-field channel can be exploited for the inter-user interference mitigation, especially for the worst case, where the users’ angular positions overlap to a great extent. (ii) For the imperfect CSI case, the channel estimation error is considered for the derivation of the closed-form SE under MRT. It shows that in the low transmit power regime, the system SE can be enhanced by increasing the pilot power and the antenna element density, the latter of which will lead to severe mutual coupling. In the high transmit power regime, increasing the pilot power has a limited effect on improving the system SE. However, increasing the antenna element density remains highly beneficial for enhancing the system SE. Finally, both analytical and simulation results confirm that reducing the antenna spacing will be accompanied by significant mutual coupling effects, which may potentially enhance the system SE. However, this enhancement is ultimately limited by the radiation efficiency of the antennas and the physical size of the array
Disinformation and democracy on the docket: reformulating the approach to electoral disinformation under the ECHR
No full textWith the pending case of Bradshaw and others v United Kingdom, the European Court of Human Rights finds itself at a crossroads: it can either cement its free elections jurisprudence under article 3 of Protocol 1 (P1-3) of the European Convention on Human Rights or it can recalibrate and refine it to better safeguard the electorate’s democratic rights in the face of electoral disinformation and foreign information manipulation and interference. This article makes the doctrinal and normative case for the latter option. We scrutinise three limitations in the jurisprudence: first, the Court’s individualised approach to electoral falsehoods under P1-3, at the expense of the electorate’s rights as informed democratic participants; second, the focus on reactive positive obligations to combat electoral disinformation, rather than proactive measures to ensure the free expression of voter choice; and finally, the lack of clarity about how the rights to free elections and to freedom of expression should be read harmoniously where they conflict.<br/
Shaping national rare diseases definition in Saudi Arabia: outcome from health ecosystem multisectoral workshop
No full textIntroduction: Rare diseases are characterized by low prevalence, a profound impact on patients, and significant challenges in accessing treatment. In Saudi Arabia, the absence of an official definition hampers policymaking, resource allocation, and orphan drugs accessibility. This study aimed to address this gap by proposing a definition of rare diseases using inputs and views from a Saudi multi-stakeholder workshop.Methods: A 1-day workshop was hosted in collaboration with the Saudi Health Council in Riyadh on 5 June 2023, involving 59 participants from various sectors, including clinicians, policymakers, patient advocates, and industry professionals. Using the Vevox® platform, participants engaged in structured activities comprising a demographic survey and 10 interactive voting sessions. Preferred qualitative and quantitative criteria for defining rare diseases were identified and analyzed using descriptive statistics and thematic and content analysis of open-ended questions.Results: The findings indicated a strong preference (96%) for an integrated definition combining qualitative and quantitative criteria. Key qualitative terms such as “Disease” (62%), “Serious” (53%), and “Disorder” (51%) were favored for their clarity and broad applicability. “Genetic” etiology was preferred by 91% of participants, citing its relevance and data availability. Patient-centered criteria, including “life-threatening” (73%) and “considerable reduction in quality of life” (91%), were emphasized. Economic and resource-focused considerations, such as “Lack of Resources” and “Combined Efforts to Prevent” (each at 60%), reflected key unmet needs in the current healthcare landscape. Among quantitative criteria, “Prevalence” (82%) emerged as the most accepted, aligned with international practices, although opinions were mixed on the inclusion of population size thresholds, underscoring the definitional complexity of defining RDs with both precision and flexibility.Discussion: This study provides a foundational basis and scientific root for defining rare diseases in the Saudi context, addressing key gaps in healthcare policies. By integrating evidence-based, patient-centered, and resource-oriented criteria, the proposed definition supports equitable access, improved patient care, and sustainable innovation, in alignment with Saudi Arabia’s Vision 2030 goals. Further refinement with broader stakeholder inputs is essential for the successful integration of Saudi healthcare policies.<br/
Consensus on the descriptors, definitions, and reporting methods for heading in football studies: A Delphi study
No full textHeading in football (soccer) is a complex skill involving deliberate head-to-ball contact, which may pose short-, medium-, and long-term risk to player brain health. However, understanding header exposure during matches and training sessions, as well as comparing header incidence between studies is currently challenging given the lack of standardisation in descriptors, definitions, and reporting methods. This Delphi study aimed to establish a consensus on the descriptors, definitions, and reporting methods for heading in football research to improve consistency and quality. The study involved 167 participants from diverse football-related backgrounds including coaches, players, medical personnel, and researchers, with consensus achieved to include 27 descriptors in minimum reporting criteria for heading in football research. An additional 27 descriptors were also defined for inclusion in an expanded framework. The operational definition of a header was standardised as "a head-to-ball contact where the player makes a deliberate movement to redirect the trajectory of the ball using their head." The consensus framework provides a standardised approach to heading in football research to enhance data quality and comparability across studies. Improved header incidence data quality has the potential to contribute significantly to our understanding of the risks associated with heading in football to inform future research and practice guidelines
Higher dose corticosteroids in hospitalised COVID-19 patients requiring ventilatory support (RECOVERY): a randomised, controlled, open-label, platform trial
No full textBACKGROUND: Low dose corticosteroids (e.g., 6 mg dexamethasone) have been shown to reduce mortality for hypoxic COVID-19 patients. We have previously reported that higher dose corticosteroids cause harm in patients with clinical hypoxia but not receiving ventilatory support (the combination of non-invasive mechanical ventilation, including high-flow nasal oxygen, continuous positive airway pressure and bilevel positive airway pressure ventilation, and invasive mechanical ventilation or extra-corporeal membrane oxygenation), but the balance of efficacy and safety in patients receiving ventilatory support is uncertain.METHODS: This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) assessed multiple possible treatments in patients hospitalised for COVID-19. Eligible and consenting adult patients receiving ventilatory support were randomly allocated (1:1) to either usual care with higher dose corticosteroids (dexamethasone 20 mg once daily for 5 days followed by 10 mg once daily for 5 days or until discharge if sooner) or usual standard of care alone (which includes dexamethasone 6 mg once daily for 10 days or until discharge if sooner). The primary outcome was 28-day mortality; secondary outcomes were duration of hospitalisation and (among participants not on invasive mechanical ventilation at baseline) the composite of invasive mechanical ventilation or death. Recruitment closed on 31 March 2024 when funding for the trial ended. The RECOVERY trial is registered with ISRCTN (50189673) and clinicaltrials.gov (NCT04381936).FINDINGS: Between 25 May 2021 and 9 January 2024, 477 COVID-19 patients receiving ventilatory support were randomly allocated to receive usual care plus higher dose corticosteroids vs. usual care alone (of whom 99% received corticosteroids during the follow-up period). Of those randomised, 221 (46%) were in Asia, 245 (51%) in the UK and 11 (2%) in Africa. 143 (30%) had diabetes mellitus. Overall, 86 (35%) of 246 patients allocated to higher dose corticosteroids vs. 86 (37%) of 231 patients allocated to usual care died within 28 days (rate ratio [RR] 0.87; 95% CI 0.64-1.18; p = 0.37). There was no significant difference in the proportion of patients discharged from hospital alive within 28 days (128 [52%] in the higher dose corticosteroids group vs. 120 [52%] in the usual care group; RR 1.04, 0.81-1.33]; p = 0.78). Among those not on invasive mechanical ventilation at baseline, there was no clear reduction in the proportion meeting the composite endpoint of invasive mechanical ventilation or death (76 [37%] of 206 vs. 93 [45%] of 205; RR 0.79 [95% CI 0.63-1.00]; p = 0.05).INTERPRETATION: In patients hospitalised for COVID-19 receiving ventilatory support, we found no evidence that higher dose corticosteroids reduced the risk of death compared to usual care, which included low dose corticosteroids.FUNDING: UK Research and Innovation (Medical Research Council) and National Institute for Health Research (Grant ref: MC_PC_19056), and Wellcome Trust (Grant Ref: 222406/Z/20/Z).</p
Exploring the long-term utility of remotely monitored FeNO suppression testing in severe asthma
No full textBackgroundConfirmation of optimal inhaled corticosteroid use is essential before initiating biologic therapy. Fractional exhaled nitric oxide (FeNO) suppression testing (FeNOSuppT) is a proven phenotyping technique; however, its long-term effect on clinical outcomes remains unclear.ObjectivesTo assess the real-world feasibility of delivering FeNOSuppT alongside digital inhaler monitoring and to examine its effect on biologic initiation and clinical outcomes.MethodsProspective cohort study within 7 U.K. severe asthma centers. Patients received a sensor-enabled inhaled corticosteroid/long-acting β-agonist (ICS/LABA) inhaler during an initial appointment between July 2020 and June 2022. A positive FeNOSuppT was defined as greater than 42% FeNO reduction at short-term follow-up (typically 1–3 mo postbaseline). Biologic initiation and clinical outcomes were compared at short-term and long-term (typically 12 mo postbaseline) follow-up.ResultsOf 353 included patients, 257 (72.8%) completed the FeNOSuppT and 140 (54.5%) were positive. A positive FeNOSuppT was associated with greater improvements in the % predicted short-term forced expiratory volume in 1 second (FEV1%; 8.6% vs –0.3; P < .001) and the 6-Item Asthma Control Questionnaire (ACQ6; 0.7 vs 0.3; P = .001) compared with a negative test. Of 168 patients eligible for biologics who completed the FeNOSuppT, those with a positive result initiated biologics less often (48.2% vs 65.2%; P = .035). Despite this, there was a greater improvement in FEV1 (11.0% vs 2.3%; P = .016), and a similar reduction in both asthma symptoms (ACQ6 0.7 vs 0.8; P = .623) and exacerbations (66.7% vs 66.7%; P = .349) at long-term follow-up when compared with those with a negative FeNOSuppT.ConclusionsDelivering FeNOSuppT aligned with digital monitoring is feasible within routine care. A positive FeNOSuppT was associated with lower rates of biologic initiation, with similar clinical outcomes.<br/
Systematic refinement of experimental practices to improve repeatability in flow battery cycling
No full textFlow batteries represent one of the leading options for large-scale, long-duration energy storage. In recent years, research into this technology has accelerated, with numerous innovative studies focusing on electrolytes, membranes, and electrode materials. Despite this, there is presently no clear set of testing protocols followed during full-cell testing of flow batteries and the experimental techniques detailed in published literature are often insufficient to reproduce results. Furthermore, testing to quantify the repeatability of experiments is not often reported. In this work, various aspects of an experimental procedure developed from the peer-reviewed literature are refined, with voltage efficiency, coulombic efficiency, energy efficiency, and electrolyte utilization used as indicators of repeatability. A set of improved testing protocols are presented for researchers to consider when conducting charge–discharge testing, and additional factors to be reported and studied in the context of repeatability are suggested
Educational experience of children living with congenital heart disease: a systematic scoping review
No full textBackground:Educational experience of children with CHD is often adversely impacted by factors such as medical burden, social and school functioning challenges. It is, therefore, vitally important that adequate support is provided at an early stage in order to facilitate better educational outcomes for this cohort. The role of the teacher is pivotal in supporting the overall healthy development of a child with CHD. Thus, it is important to understand how we can also support teachers to provide optimal support to this cohort. This systematic scoping review aimed to offer a comprehensive understanding of existing research in this area and identify any knowledge gaps.Methods:The methodological framework for scoping reviews developed by Arksey and O’Malley (2005) was employed.Findings:Children with CHD face educational challenges in cognitive, psychomotor, behavioural, and affective domains and also with school attendance. The main challenges for teachers include a lack of information around CHD and how it affects the individual child. Building a strong relationship and having frequent communication between the teacher/ parent/ child were considered key in alleviating anxiety and promoting a supportive environment.Conclusions:Children with CHD often require additional support from educational professionals in the classroom. Teachers of children with CHD would benefit from condition-specific training, updated on a regular basis.<br/
Collective post-traumatic growth: Validating and measuring positive change in the collective self among victims of sexual violence
No full textAcross the world, women's personal responses to gender-based violence are increasingly political. In the current paper, we consider whether positive changes in the collective self, arising from personal experience of gender-based violence, which may lie at the heart of this phenomenon, can be evidenced. Four studies are reported that evidence and validate a proposed construct that reveals collective post-traumatic growth (PTG) among people who have experienced sexual violence. Confirmatory factor analyses, including a preregistered analysis, indicate that collective PTG is a multidimensional construct and is distinct, yet related to personal PTG. A longitudinal analysis offers evidence of stability and highlights the importance of collective efficacy and group solidarity in determining collective PTG over time. A final experimental study provides evidence of collective PTG determining people's emotional responses to reminders of their trauma. Taken together, these studies emphasize the significance of collective growth as an often overlooked, though positive and important, sociopolitical response to direct experiences of very personal trauma.</p