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Conical Direction Finding using Frequency-Scanned Bull's-Eye Leaky-Wave Antennas for UAV Tracking Applications
Get PDFWe demonstrate the application of a Bull's-Eye (BE) leaky-wave antennas (LWA) for enhanced conical direction finding, leveraging its inherent conical-beam frequency-scanning capability. Unlike uniform or quasi-uniform 2D LWAs, such as Fabry-Perot Antennas, the 2D periodic BE-LWA uses a higherorder space harmonic to radiate. This enables the use of both backward- and forward-scanning frequency bands to improve the conical direction-finding performance, when compared to the use of a single scanning band. Also, the BE LWA presents rotational symmetry and thus more stability in the direction finding performance for any azimuthal angle. This is demonstrated with experiments using a printed-circuit BE LWA offering a total scanning operating band from 14 GHz to 32 GHz and covering an elevation field-of-view of 120° with fully-azimuthal symmetry
Thinned Sub-Array Antenna Design Enabling Dual-Polarization Monopulse Patterns and Beam Steering for Integrated Sensing and Communication Systems
Get PDFA high-isolation slot antenna array design is presented offering dual-polarization, sum and difference beam patterns with high isolation for integrated sensing and communications (ISAC) applications. The 16-port single-layer design is competitive when compared to the state-of-the-art, and is defined by a sub-array arrangement in a cross-shaped orientation and this setup is made possible by light element thinning of the planar array. Also, the antenna has been designed considering dual-differential, dual-common, or common/differential feeding to generate reconfigurable or agile sum and difference beam patterns as required in the far-field for communications, sensing, or monopulse tracking. Measured isolation ranges for these cases are well above 55 dB for the antenna system ports. Additionally, the maximum realized gain for both polarizations is approximately 22 dBi. We have also demonstrated the beam-steering capabilities of our antenna array using a Butler matrix beamformer, which enables steering up to ±60°. This approach not only provides flexible control over the radiation pattern but also maintains high isolation between the dual-polarization beams. A case study is further reported demonstrating the proposed antenna in a realistic ISAC system setup. Such a low profile, microwave/millimeter-wave antenna array with high isolation can also be useful for full-duplex communication systems, dual-polarized radar sensing, other tracking applications, or whenever a dual-polarization antenna array for beam-steering is required
Cultural studies, geography, and the mediation of disasters:Reflections on Burgess and Gold 40 years on
Get PDFThis forum to revisit a landmark edited collection serves as an important reminder to geographers that media and popular culture have been central to geographical scholarship for at least four decades. The book’s contributions underscore the significance of popular media for research in geography and the centrality of geographical considerations and concerns for the analysis of media texts, production and consumption practices. Communication can only occur across and indeed creates space, the locations of media production and consumption saturate contemporary everyday life, the mediation of places is both constitutive of their meaningfulness and a site of its ongoing contestation, and engagement with media offers important insights for many forms of geographical enquiry, including the study of development; racial, national, regional and domestic imaginaries; urban placemaking and change; and hazard and disaster management. In this article we take up two key issues raised by the volume in question that connect with our own work and with the wider geographical study of media. The first is the relationship between geography and cultural studies discussed by Burgess and Gold in their introductory chapter. The second concerns representations of disaster in media, which are explored in Liverman and Sherman’s contribution to the collection
The availability, price, and marketing characteristics of organic foods and beverages: a comparative food environment assessment
Get PDFBackground: Demand for organic foods remains low, despite the potential of organic products to contribute to sustainable food systems. Food purchasing decisions are influenced by the food environment, yet no study has systematically evaluated food environment dimensions for organic products. Methods: We developed an organic food environment assessment tool that evaluates the availability, price, vendor and marketing characteristics of organic foods in urban food environments. We implemented the tool in nine cities across Brazil, India, and the United Kingdom for 14 sentinel products.Results: We found that only 37% of 808 surveyed vendors sold an organic option. Organic rice was 1.8-2.5 times the price of non-organic rice. Only 8% of organic products used a price promotion, while 62% displayed a certification label. In India, health benefits were the predominant marketing message (59% of organic foods); in the UK, it was environmental benefits (50%).Conclusion: Our findings indicate a need for a more evidence-based strategy in marketing organic foods and beverages to consumers. There is a need for further research and implementation of marketside initiatives to boost demand for organic foods and beverages in order to encourage a shift towards more sustainable food systems
An RNA sequencing dataset from a porcine immortalized pre-adipocyte cell line
Get PDFThere is a significant need for livestock cell lines that can be robustly expanded in culture while maintaining their functional characteristics, both for use as in vitro models to understand animal physiology and for industrial applications such as in the emerging sector of cellular agriculture. Here we describe RNA sequencing datasets from a spontaneously immortalized pre-adipocyte line that was derived through serial passaging of porcine adipose-derived mesenchymal stromal cells (MSCs). This cell line, known as FaTTy, is unique in that it displays enhanced adipogenic capacity during long-term culture, characterised by a close to 100% differentiation efficiency and the ability to generate mature adipocytes. Bulk RNA sequencing was performed from FaTTy and parental MSCs. We present analysis of the raw files and bioinformatics analyses, including differential gene expression. These data provide valuable insight on the mechanisms of cell immortalization and the unique phenotype of the FaTTy cell line, with distinctive advantages as a prospective cell source for cultivated fat manufacture.</p
Interpretable Machine Learning based Detection of Coeliac Disease
Get PDFBackground: Coeliac disease, an autoimmune disorder affecting approximately 1% of the global population, is typically diagnosed on duodenal biopsy. However, inter-pathologist agreement on coeliac disease diagnosis is only 80%. Existing machine learning solutions designed to improve coeliac disease diagnosis often lack interpretability, which is essential for building trust and enabling widespread clinical adoption.Objective: To develop an interpretable AI model segmenting key histological structures in H&E-stained duodenal biopsies, generating explainable segmentation masks, estimating intraepithelial lymphocyte (IEL)-to-enterocyte and villus-to-crypt ratios, and diagnosing coeliac disease.Design: Semantic segmentation models were trained to identify villi, crypts, IELs, and enterocytes using 49 annotated 2048x2048 patches at 40x magnification. Subsequently, IEL-to-enterocyte and villus-to-crypt ratios were calculated from segmentation masks generated by the segmentation model from 172 whole slide images (WSIs), and a logistic regression model was trained to diagnose coeliac disease based on these ratios. Evaluation was performed on an independent test set of 613 WSIs from an independent medical institution.Results: The villus-crypt segmentation model achieved mean Precision-Recall-AUC of 80.5%, while the IEL-enterocyte model reached Precision-Recall-AUC of 82%. The diagnostic model classified WSIs with 96% accuracy, 86% positive predictive value, and 98% negative predictive value on the independent test set. Conclusions: Our interpretable AI models accurately segmented key histological structures and diagnosed coeliac disease in unseen WSIs, demonstrating strong generalization performance. These models provide pathologists with reliable IEL-to-enterocyte and villus-to-crypt ratio estimates, enhancing diagnostic accuracy. Interpretable AI solutions like ours are essential for fostering trust among healthcare professionals and patients, complementing existing black-box methodologies.<br/
Quantifying the correlation between variance components: An extension to the double-hierarchical generalised linear model
Get PDFThe variational properties of biological systems are an increasing focus of current research, and statistical methods are required for drawing inferences about the processes that determine them. Double-hierarchical generalised linear models (DHGLM) are ideally suited for studying variational properties since they provide a direct way of modelling the distribution of variances. Although DHGLM have mainly been used to model heterogeneous residual variances over groups, models have been proposed that also allow heterogeneous random effect variances. However, these multi-way DHGLM make the assumption that the residual variance of a group is independent of its random-effect variance. Here, using a Bayesian approach, we extend multi-way DHGLMs so that the correlation between residual- and random-effect variances can be estimated. Using simulated data, the performance of the model is compared with the non-DHGLM models that have traditionally been used to estimate such correlations. The proposed model is shown to perform well at estimating all model parameters, and in particular performs better than alternative models at estimating the correlation among variance components. Numerical analyses are complemented with theoretical work showing the expected bias when using non-DHGLM models. In some cases, commonly used non-DHGLM models are even expected to get the sign of the correlation wrong.</p
Sex in the medical machine:How algorithms can entrench bioessentialism in precision medicine
Get PDFMachine learning offers new possibilities for developing more precise diagnostics and treatments, but the increasing use of sex stratification in precision medicine algorithms raises concerns. Using Alzheimer's disease (AD) research as an example in which machine learning approaches are applied to a heterogenous, socially patterned disease, this paper examines how the move toward sex-specific "pink" and "blue" algorithms reinforces biological sex essentialist assumptions and their attendant harms. We analyze three examples of sex-stratified algorithmic approaches in AD research, and identify three interacting processes— effacing contested knowledge, obscuring social factors, and ossifying binary sex categories—that can occur when binary sex variables are incorporated into predictive models. These case studies demonstrate that even in models intended to be causally agnostic, sex categories are likely to be interpreted as decontextualized, self-evident health determinants in a manner that can imply causality of biological sex. We call for establishing ethical norms and empirical standards for including gender/sex variables in precision medicine algorithms to avoid perpetuating crude ontologies of sex and gender that undermine both scientific validity and health justice
Three maxims for countering sex essentialism in scientific research
Get PDFTo explain observed disparities in health outcomes between men and women, sex essentialist approaches assign causal primacy to sex-related biology. In this essay, we present three case studies to illustrate how sex essentialism can distort human biomedical research and distill three maxims for countering this distortion: (1) engage in responsible citation practices; (2), generate and weigh alternative hypotheses for apparent observations of sex differences; (3) take care in constructing the appropriate denominator when making sex comparisons. We offer these maxims as broadly applicable standards of evidence to guide biomedical research that includes analysis of potential sex differences, as well as to support Institutional Review Boards (IRBs), funders, publishers, and peer reviewers in evaluating sex difference findings. If widely applied, these maxims would substantially improve the rigor, precision, and utility of the knowledge base of sex and gender science
The UK food environment: a systematic review of domains, methodologies and outcomes
Get PDFUnderstanding food environments is crucial for developing policies and interventions to enhance the healthfulness and sustainability of UK diets. We systematically reviewed published scientific research to answer 2 research questions. First, what types and domains of the food environment have been assessed in the United Kingdom using what methodologies? Domains included availability, affordability, promotion, product characteristics/quality, convenience, and sustainability. Second, what outcomes have been assessed in relation to food environments? Outcomes were classified as descriptive (describing the food environment), dietary intake, and health. Articles published between January 2000 and December 2024 were identified by searching 7 databases: CAB Abstracts, CINAHL, EMBASE, Global Health, PubMed, Scopus, and Web of Science. A total of 31,457 articles were identified, 3418 full texts were reviewed, and 286 articles were included. Another 26 articles were included after screening the references of articles identified in the database search. Thus, data were extracted from a total of 312 articles. The most common domain studied was availability (n = 100, 32%), followed by product characteristics/quality (n = 94, 30%) and promotion (n = 33, 10%). There was a paucity of research on the domains of sustainability (n = 19, 6%) and affordability (n = 16, 5%), with no articles on the domain of convenience. Only 49 articles (16%) evaluated >1 domain. Most articles were descriptive (n = 206, 66%); 64 (20%) evaluated the association of the food environment with dietary intake and 42 (13%) evaluated the association with health, nearly all with obesity. The current literature on the food environment in the United Kingdom focuses largely on availability in the food retail space. More research is needed to understand how different domains of the food environment interact to influence dietary intake and health. The protocol was registered at PROSPERO as CRD42022306066 on 8 February 2022.</p
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