143174 research outputs found
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Single-mode emission by phase-delayed coupling between nanolasers
No full textNear-field coupling between nanolasers enables collective high-power lasing but leads to complex spectral reshaping and multimode operation, limiting the emission brightness, spatial coherence, and temporal stability. Many lasing architectures have been proposed to circumvent this limitation based on symmetries, topology, or interference. We show that a much simpler and robust method exploiting phase-delayed coupling, where light exchanged by the lasers carries a phase, can enable stable single-mode operation. Phase-delayed coupling changes the modal amplification: for pump powers close to the anyonic parity-time (PT) symmetric exceptional point, a high phase delay completely separates the mode thresholds, leading to single-mode operation. This is shown by stability analysis with nonlinear coupled mode theory and stochastic differential equations for two coupled nanolasers and confirmed by a realistic semianalytical treatment of a dimer of lasing nanospheres. Finally, we extend the mode control to large arrays of nanolasers featuring lowered thresholds and higher power. Our work promises a novel solution to engineer bright and stable single-mode lasing from nanolaser arrays with important applications in photonic chips for communication and LIDAR
Randomized transport plans via hierarchical fully probabilistic design
No full textAn optimal randomized strategy for design of balanced, normalized mass transport plans is developed. It replaces—but specializes to—the deterministic, regularized optimal transport (OT) strategy, which yields only a certainty-equivalent plan. The incompletely specified—and therefore uncertain—transport plan is acknowledged to be a random process. Therefore, hierarchical fully probabilistic design (HFPD) is adopted, yielding an optimal hyperprior supported on the set of possible transport plans, and consistent with prior mean constraints on the marginals of the uncertain plan. This Bayesian resetting of the design problem for transport plans—which we call HFPD-OT—confers new opportunities. These include (i) a strategy for the generation of a random sample of joint transport plans; (ii) randomized marginal contracts for individual source-target pairs; and (iii) consistent measures of uncertainty in the plan and its contracts. An application in fair market matching is outlined, in which HFPD-OT enables the recruitment of a more diverse subset of contracts—than is possible in classical OT—into the delivery of an expected plan
Maximising the potential of temporal Ne estimation in long‐term population monitoring programmes
No full textAnaphylaxis definition, overview, and clinical support tool: 2024 consensus report—a GA²LEN project
No full textBackground
The 2006 National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network anaphylaxis criteria are widely used in clinical care and research. In 2020, the World Allergy Organization published modified criteria that have not been uniformly adopted. Different criteria contribute to inconsistent care and research outcomes.
Objective
We sought to develop a consensus anaphylaxis definition, overview, and clinical support tool.
Methods
A 12-member writing group developed draft outputs modified with input from a 46-member international expert panel, 31 medical stakeholder organizations, and 15 patient advocacy organizations. The expert panel participated in a modified Delphi process to seek consensus for the outputs using a ≥80% consensus threshold.
Results
The first sentence of the definition reads, “Anaphylaxis is a serious allergic (hypersensitivity) reaction that can progress rapidly and may cause death.” The definition also describes organ systems that may be involved and signs of life-threatening reactions. The overview includes details of anaphylaxis recognition and management. The clinical support tool incorporates new clinical criteria to help determine the likelihood that patients are having anaphylaxis, intramuscular epinephrine indications and dosing, and common findings from the anaphylaxis organ systems. In addition, 93.5% (43/46), 97.8% (45/46), and 93.5% (43/46) of experts agreed with the definition, overview, and clinical support tool, respectively.
Conclusion
The anaphylaxis overview is a novel educational tool conveying key elements of anaphylaxis recognition and management. We propose that the definition and clinical support tool should replace previous definitions and clinical criteria. The clinical support tool should facilitate improved anaphylaxis recognition and management across different clinical settings and standardize research outcomes
Socioeconomic deprivation and opioid consumption: an analysis across England
No full textConcerns sparked by the US opioid epidemic have led to increased attempts to reduce England’s overall opioid consumption. Variations in health literacy across the country have led to differing prescribing practices, with increased chronic conditions appearing in areas of increased socioeconomic deprivation. This review investigated the relationship between increased opioid utilization and increased socioeconomic deprivation, aiming to highlight areas of England which have the highest opioid consumption. The review has investigated a range of socioeconomic factors, such as unemployment and fuel poverty, which have consequently influenced the higher frequency of opioid prescribing in areas where these factors were highest. Opioid abuse was most prevalent in areas with higher levels of deprivation. Geographically, areas with the highest levels of deprivation, and consequent opioid consumption, were situated in the North of England, with cities like London having a significantly lower consumption rate in comparison. These trends are a good starting point when designing future opioid epidemic-prevention strategies, as specific areas can be targeted to propel a reduction in opioid prescribing and addiction and thus decrease the likelihood of an opioid crisis forming. Although a longitudinal study would have strengthened the findings of this review, it was not feasible due to practical constraints
HNF1A and A1CF coordinate a beta cell transcription-splicing axis that is disrupted in type 2 diabetes
No full textType 2 diabetes (T2D) is a devastating chronic disease marked by pancreatic b-cell dysfunction and insulin resistance, whose pathophysiology remains poorly understood. HNF1A, which encodes transcription factor Hepatocyte Nuclear Factor-1alpha, is the most commonly mutated gene in Mendelian diabetes, yet also carries loss- or gain-of-function coding variants that predispose or protect against polygenic T2D, respectively. The mechanisms underlying HNF1A-deficient diabetes, however, are still unclear. We now demonstrate that diabetes arises from β-cell-autonomous defects, and identify direct b-cell genomic targets of HNF1A. This uncovered a regulatory axis where HNF1A controls transcription of A1CF, which orchestrates an RNA splicing program encompassing genes that regulate b-cell function. This HNF1A-A1CF transcription-splicing axis is suppressed in β-cells from T2D individuals, while genetic variants reducing pancreatic islet A1CF associate with increased glycemia and T2D susceptibility. Our findings, therefore, identify a linear hierarchy that coordinates β-cell-specific transcription and splicing programs, and link this pathway to T2D pathogenesis
Derivation of rectangular metallic waveguide attenuation constant for IEC 60153-2 and IEEE 1785.1 international standards
No full textThe IEC 60153-2 and IEEE 1785.1 international
standards for rectangular metallic waveguides are currently
undergoing revision. Textbook derivations of the associated
equations for the metal-pipe rectangular waveguide attenuation
constant to be given in the revised standards are presented. These
derivations provide important mathematical traceability for
these equations, which has previously not been proven in the
open literature for these standards. Furthermore, the historical
approximations used in the original equations are identified and
now corrected here. Results using the newly derived equations
are demonstrated, with comparison to experimental results in the
WM-380 (500 GHz to 750 GHz) band
Grape expectations: climate change impacts, viticulture and socio-economic systems
No full textThis research investigates impacts of climate change on viticulture, with consideration for English and Welsh vineyards, and acknowledgement of the complex relationships between the social and environmental system. A systematic map was created to methodically analyse the published scientific literature on observed impacts of climate change on viticulture. This is believed to be the first of its kind on this topic and has revealed novel insights. After screening over 12,000 articles, 158 were included for full text extraction. It was found that temperature is the most observed factor (n = 147) that is increasing (n = 142) with climate change. Alongside this, timing of phenological events was found to be increasing (n = 61) whilst the response to precipitation was either decreasing or ambiguous (n = 62). Grapes were found to be increasing in sugar (n = 25) and alcohol content (n = 16) and decreasing in acidity (n = 17). Wine quality and fruit quality were found to be either decreasing or had an ambiguous response (n = 30 and n = 16 respectively), with yield also decreasing (n = 17). This poses a significant threat to grape growers and wine makers who were vastly under-represented in the literature (n = 19 and n = 8 respectively). The social-ecological system of viticulture is embedded in the concept of terroir but is also under-represented in the literature. This poses an opportunity to enhance adaptability and resilience, as viticultural stakeholders already have an appreciation for the interconnected nature of oenology. Given the emergent status of the English and Welsh wine industry, there are pertinent lessons learnt that can be extrapolated from this study that the industry would benefit from exploring further in future research, such as localised studies and further exploration of the social-ecological system.Open Acces
White paper: market design for low-inertia power systems: Ancillary services in GB
No full textIn 2021, the “Net Zero Strategy: Build Back Greener” set out the UK government’s policies and proposals for decarbonising all sectors of the UK economy [1]. This strategy states a particularly fast decarbonisation of the electricity sector. By 2035, all electricity will need to come from zero-carbon sources, which will require significant investment in low/zero carbon generation, electricity networks, different flexibility technologies and advanced control concepts, to support a cost-effective transition to a zero-carbon system without risking security of supply.
Balancing electricity supply and demand in a low-carbon electricity system is increasing in complexity due to hours with high production of Renewable Energy Sources (RES) which reduce inertia levels [2]. Inertia is an element available in synchronous generators and loads that can resist drops in frequency, giving the grid time to rebalance supply and demand. Frequency must always be close to the nominal operating point (50 Hz in the UK) in order to maintain security of supply (avoid customer disruptions), even when a generation or load outage occurs. The inertia in rotating steam, gas or hydroelectric turbines naturally slows the rate at which frequency changes after a fault, but most RES, such as wind and solar photovoltaic (PV), do not currently provide any inertia. This means power systems are becoming more vulnerable to frequency deviations, making frequency containment Ancillary Services (AS) more valuable during hours with high-RES generation. Great Britain (GB) during the COVID-19 national lockdown [3], is a very informative example of this trend.
In this context, security of supply for low carbon electricity systems is recognised as a growing challenge for system operators. However, current electricity markets do not provide clear incentives for maintaining frequency security [4]. Moreover, consideration of services such as inertia, which depends on the amount of generation synchronised to the grid, challenge current pricing mechanisms[5].
This white paper, Market design for low-inertia power systems: Ancillary services in GB, proposes a novel market mechanism that will align the market design with the simultaneous scheduling of energy and frequency containment AS provision in an economic and efficient manner. AS provision will be potentially addressed by a wide variety of providers, including conventional synchronous generators, RES, storage systems, and Electric Vehicles (EVs), which will be incentivised by the proposed future market design. Furthermore, this methodology provides a new framework for allocating the cost of procuring frequency containment AS among the market players that trigger these requirements. The proposed methodology distributes the payments for frequency containment AS among all the market participants that create the need for these services.
This novel market design will provide appropriate incentives for the development/deployment of advanced technologies and control concepts to support a cost-effective transition to a secure low/zero-carbon electricity system, through the provision of appropriate AS. Although at present, electricity consumers directly pay for all AS costs (i.e., costs are socialised), we argue that electricity generators should be responsible for covering these costs, as it is detailed in [6]. This cost allocation is inspired by the work presented in [7], in which contingency reserve costs are allocated among generation units considering their size and probability of unavailability. This market design is the core new concept, shifting from the historical approach based on socialising AS costs, to an efficient cost allocation concept recognising that the size of the plant is the key driver for these costs.
This white paper concludes by highlighting the potential impact of the proposed market design on advancing technology deployment and supporting a cost-effective transition to a secure low-carbon electricity system
Implanted high-density electrode arrays to connect with the human spinal cord
No full textNeural interface technologies aim to bridge the gap between the nervous system and external environment,
offering both clinical applications for individuals with impairments and enhancement capabilities for healthy users. While various interface approaches exist across different neural pathway levels, muscle-level interfaces through electromyography (EMG) present a particularly promising avenue by capturing neural signals as they transform into physical actions. Although surface EMG provides insights into global muscle activity, its effectiveness is limited by filtering of the signal through the conductive tissue. Intramuscular EMG, especially when recorded via multichannel electrodes, offers more direct access to neural signals—yet the full potential of intramuscular multichannel electrodes remains unexplored, with current decoding algorithms not optimized for these advanced recording capabilities.
This thesis advances the field through the characterization of a novel intramuscular multichannel micro-electrode array. I collected a novel dataset of multichannel intramuscular EMG recordings from forearm and leg muscles in healthy participants, which supported several key contributions:
(1) development of a novel algorithm to extract (decode) the neural information from high-density intramuscular EMG, later adapted for surface EMG applications; (2) systematic analysis of electrode parameters’ impact on decoding performance; and (3) demonstration of a proof-of-concept offline system for gesture control using motor neuron decoding and mapping. These advances lay the groundwork for more sophisticated neural interfaces that could enhance both clinical applications and human-machine interaction.Open Acces