143174 research outputs found
Sort by
Fifteen-minute consultation: should I get my child the varicella (chickenpox) vaccine?
No full textThe Joint Committee on Vaccination and Immunisation (JCVI) has recently recommended the introduction of the varicella (chickenpox) vaccine into the UK’s routine childhood immunisation schedule. This was previously only available to a small group of eligible children or through private healthcare providers. Engaging families in conversations around vaccines is recognised as important for informed decision-making, and professionals leading these discussions need to be confident and well-informed. This article aims to provide an overview of the evidence behind the decision to introduce varicella (chickenpox) vaccine, and addresses anticipated questions
Interracial frontline encounters: how white customers’ stereotype threat affects black frontline employees’ immediate job outcomes
No full textInterracial interactions are often laden with concerns about being assimilated by group stereotypes. This
study examines the “White-and-prejudiced” stereotype threat, which can be triggered in White customers
when interacting with Black frontline employees. Our findings, derived from two field studies and two
experiments, reveal short-term positive effects of the White stereotype threat on the job performance
effectiveness of Black frontline employees. For example, White customers buy more and intend to tip more
when interacting with a Black relative to a White frontline employee. These short-term positive behavioral
shifts toward Black frontline employees are especially present when the frontline employee is categorized in
terms of race but diminished when the frontline employee is individuated. The implications of our findings
are managerially relevant because employees from marginalized racial groups are often overrepresented in
frontline and in service occupations in several countries including Europe and the United States
Direct observations of solute dispersion in rocks with distinct degree of sub-micron porosity
No full textThe transport of chemical species in rocks is affected by their structural heterogeneity to yield a wide spectrum of local solute concentrations. To quantify such imperfect mixing, advanced methodologies are needed that augment the traditional breakthrough curve analysis by probing solute concentration within the fluids locally. Here, we demonstrate the application of asynchronous, multimodality imaging by X-ray computed tomography (XCT) and positron emission tomography (PET) to the study of passive tracer experiments in laboratory rock cores. The four-dimensional concentration maps measured by PET reveal specific signatures of the transport process, which we have quantified using fundamental measures of mixing and spreading. We observe that the extent of solute spreading correlate strongly with the strength of subcore-scale porosity heterogeneity measured by XCT, while dilution is enhanced in rocks containing substantial sub-micron porosity. We observe that the analysis of different metrics is necessary, as they can differ in their sensitivity to the strength and forms of heterogeneity. The multimodality imaging approach is uniquely suited to probe the fundamental difference between spreading and mixing in heterogeneous media. We propose that when multi-dimensional data is available, mixing and spreading can be independently quantified using the same metric. We also demonstrate that one-dimensional transport models have limited predictive ability toward the internal evolution of the solute concentration, when the model is solely calibrated against the effluent breakthrough curves. The data set generated in this study can be used to build realistic digital rock models and to benchmark transport simulations that account deterministically for rock property heterogeneity
The role of agricultural ashes (rice husk ash, coffee husk ash, sugarcane bagasse ash, palm oil fuel ash) in cement production for sustainable development in Africa
No full textOrdinary Portland cement (OPC) is produced through energy-intensive processes and contributes to approximately 8% of global carbon dioxide emissions. As one of the most consumed materials after water, cement's environmental impact is substantial. Decarbonizing emissions in the intensive processes of cement production requires a sustainable supply of low-carbon resources. The purpose of this study is to explore the potential of agricultural waste ashes as supplementary cementitious materials (SCMs) to reduce the carbon footprint of OPC. In Africa, where agricultural waste is abundant, these residues could offer a sustainable solution for cement manufacturing. This study employed a multi-criteria decision analysis methodology to identify and select relevant literature for analysis. The review reveals that incorporating agricultural-based SCMs, such as rice husk ash, coffee husk ash, sugarcane bagasse ash, and palm oil fuel ash, into cement production can significantly reduce clinker requirements, thereby lowering carbon dioxide emissions while maintaining performance standards of OPC. The review found that locally sourced waste materials can reduce the carbon footprint of cement by up to 40%. Transitioning from a clinker-dependent sector to a bio-based one presents several opportunities as well as challenges for the African cement industry, but it is critical for reducing carbon emissions and improving sustainability. This approach not only decreases emissions but also supports sustainable construction, aligning with global climate goals and sustainable development goals (SDGs) 12 (responsible consumption and production) and 13 (climate action). Adopting green cement could revolutionize the African cement industry, promoting resource efficiency and sustainable development across the continent
Permanent magnetic droplet-derived microrobots
No full textMicrorobots hold significant potential for precision medicine. However, challenges remain in balancing multifunctional cargo loading with efficient locomotion and in predicting behavior in complex biological environments. Here, we present permanent magnetic droplet-derived microrobots (PMDMs) with superior cargo-loading capacity and dynamic locomotion capabilities. Produced rapidly via cascade tubing microfluidics, PMDMs can self-assemble, disassemble, and reassemble into chains that autonomously switch among four locomotion modes—walking, crawling, swinging, and lateral movement. Their reconfigurable design allows navigation through complex and constrained biomimetic environments, including obstacle negotiation and stair climbing with record speed at the submillimeter scale. We also developed a molecular dynamics-based computational platform that predicts PMDM assembly and motion. PMDMs demonstrated precise, programmable cargo delivery (e.g., drugs and cells) with post-delivery retrieval. These results establish both a physical and in-silico foundation for future microrobot design and represent a key step toward clinical translation. Teaser: Permanent magnetic droplet-derived microrobots possess enhanced cargo-loading and locomotion capabilities
Coherent spectroscopy with a single antiproton spin
No full textCoherent quantum transition spectroscopy is a powerful tool in metrology¹, quantum information processing², magnetometry³, and precision tests of the Standard Model⁴. It was applied with great success in proton and deuteron magnetic moment measurements⁵, which culminated in MASER spectroscopy with sub-parts per trillion resolution⁶ and many other experiments at the forefront of physics⁷. All these experiments were performed on macroscopic ensembles of particles, while the coherent spectroscopy of a “free” single nuclear spin has never been reported before. Here, we demonstrate coherent quantum transition spectroscopy of the spin of a single antiproton stored in a cryogenic Penning-trap system. We apply a multi-trap technique⁸, detect the antiproton spin-state using the continuous Stern-Gerlach-effect⁹, and transport the particle to the homogeneous magnetic field of a precision trap (PT). Here, we induce the coherent dynamics and analyze the result by quantum-projection measurements in the analysis trap¹⁰ . We observe for the first time Rabi-oscillations of an antiproton spin and achieve in time-series measurements spin inversion probabilities above 80% at spin coherence times of ≈ 50s. Scans of single-particle spin resonances show inversions >70%, at transition line-widths 16 times narrower than in previous measurements⁸, limited by cyclotron frequency measurement decoherence. This achievement marks a major step towards at least 10-fold improved tests of matter/antimatter symmetry using proton and antiproton magnetic moments
A primer on variational inference for physics-informed deep generative modelling
No full textVariational inference (VI) is a computationally efficient and scalable methodology for approximate Bayesian inference. It strikes a balance between accuracy of uncertainty quantification and practical tractability. It excels at generative modelling and inversion tasks due to its built-in Bayesian regularisation and flexibility, essential qualities for physics related problems. For such problems, the underlying physical model determines the dependence between variables of interest, which in turn will require a tailored derivation for the central VI learning objective. Furthermore, in many physical inference applications this structure has rich meaning and is essential for accurately capturing the dynamics of interest. In this paper, we provide an accessible and thorough technical introduction to VI for forward and inverse problems, guiding the reader through standard derivations of the VI framework and how it can best be realized through deep learning. We then review and unify recent literature exemplifying the flexibility allowed by VI. This paper is designed for a general scientific audience looking to solve physics-based problems with an emphasis on uncertainty quantification
Oral anticoagulation versus no anticoagulation for stroke prevention in patients with intracranial hemorrhage and atrial fibrillation: an updated meta-analysis of randomized controlled trials
No full textBackground. Oral anticoagulation (OAC) effectively reduces stroke risk in patients with atrial fibrillation (AF), but its use after intracranial hemorrhage (ICH) remains controversial due to bleeding concerns. This study aimed to update the evidence on the efficacy and safety of OAC in AF patients with a history of ICH.
Methods. A systematic review and meta-analysis were conducted according to PRISMA guidelines. We searched PubMed, Scopus, and EMBASE for randomized controlled trials (RCTs) comparing OAC versus avoid anticoagulation in AF patients post-ICH. The primary outcomes were ischemic stroke and recurrent ICH. Secondary outcomes included all-cause mortality, cardiovascular mortality, major adverse cardiovascular events (MACE), major hemorrhage, and a composite endpoint of “net clinical benefit” (first incident ischemic stroke and first incident recurrent ICH). Pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated using a random-effects model.
Results. Four RCTs with 653 participants were included. Anticoagulation was associated with a reduced risk of ischemic stroke (RR 0.23, 95%CI 0.06–0.91) and increased risk of recurrent ICH (RR 3.60, 95%CI 1.40–9.30). No significant differences were observed in all-cause mortality (RR 0.93, 95%CI 0.59-1.46), cardiovascular death (RR 1.01, 95%CI 0.32-3.18) and for net clinical benefit (RR 0.72, 95%CI 0.42-1.24). Anticoagulation was associated with a significant increased risk of any major haemorrhage (RR 2.49, 95%CI 1.29-4.81) and reduced MACE (RR 0.64, 95%CI 0.44-0.94).
Conclusions. Oral anticoagulation in patients with AF and prior ICH was associated with a reduced risk of ischemic stroke and an increased risk of recurrent ICH. PROSPERO code CRD42025637606
Intravenous rehydration for severe acute malnutrition with gastroenteritis
No full textBackground:
International recommendations advise against the use of intravenous rehydration therapy in children with severe acute malnutrition because of the concern about fluid overload, but evidence to support this concern is lacking. Given the high mortality associated with the current recommendations, the adoption of intravenous rehydration strategies might improve outcomes.
Methods:
We conducted a factorial, open-label superiority trial in four countries in Africa. Children 6 months to 12 years of age with severe acute malnutrition with gastroenteritis and dehydration underwent randomization in a 2:1:1 ratio to one of three rehydration strategies: oral rehydration, plus intravenous boluses for shock; a rapid intravenous strategy that consisted of lactated Ringer’s solution (100 ml per kilogram of body weight) administered over a period of 3 to 6 hours, with boluses for shock; or a slow intravenous strategy that consisted of the same solution administered over a period of 8 hours, with no boluses. The primary end point was death at 96 hours.
Results:
A total of 272 children underwent randomization; 138 were assigned to the oral strategy, 67 to the rapid intravenous strategy, and 67 to the slow intravenous strategy. Participants were followed for 28 days. A nasogastric tube was used for oral rehydration in 126 of 135 participants (93%) in the oral group and in 82 of 126 (65%) in the intravenous groups. Intravenous boluses were administered at admission in 12 participants (9%) in the oral group, 7 (10%) in the rapid intravenous group, and none in the slow intravenous group. At 96 hours, 11 participants (8%) in the oral group and 9 (7%) in the intravenous groups (5 in the rapid group and 4 in the slow group) had died (risk ratio, 1.02; 95% confidence interval [CI], 0.41 to 2.52; P=0.69). At 28 days, 17 participants (12%) in the oral group and 14 (10%) in the intravenous groups had died (hazard ratio, 0.85; 95% CI, 0.41 to 1.78). Serious adverse events occurred in 32 participants (23%) in the oral group, 14 (21%) in the rapid intravenous group, and 10 (15%) in the slow intravenous group. No evidence of pulmonary edema, heart failure, or fluid overload was noted.
Conclusions:
Among children with severe acute malnutrition and gastroenteritis, no evidence of a difference in mortality at 96 hours was noted between oral and intravenous rehydration strategies. (Funded by the Joint Global Health Trials scheme and others; GASTROSAM Current Controlled Trials number, ISRCTN76149273.