The Whitham equation is a non-local, nonlinear partial differential equation that models the temporal evolution of spatial profiles of surface displacement of water waves. However, many laboratory and field measurements record time series at fixed spatial locations. To directly model data of this type, it is desirable to have equations that model the spatial evolution of time series. The spatial Whitham (sWhitham) equation, proposed as the spatial generalization of the Whitham equation, fills this need. In this paper, we study this equation and apply it to water-wave experiments on shallow and deep water. We compute periodic travelling-wave solutions to the sWhitham equation and examine their properties, including their stability. Results for small-amplitude solutions align with known results for the Whitham equation. This suggests that the systems are consistent in the weakly nonlinear regime. At larger amplitudes, there are some discrepancies. Notably, the sWhitham equation does not appear to admit cusped solutions of maximal wave height. In the second part, we compare predictions from the temporal and spatial Korteweg–de Vries and Whitham equations with measurements from laboratory experiments. We show that the sWhitham equation accurately models measurements of tsunami-like waves of depression, waves of elevation, and solitary waves on shallow water. Its predictions also compare favourably with experimental measurements of waves of depression and elevation on deep water. Accuracy is increased by adding a phenomenological damping term. Finally, we show that neither the sWhitham nor the temporal Whitham equation accurately models the evolution of wave packets on deep water.

Jurisdiction simpliciter — non-resident defendant — claim for injury to person or damage to property or reputation — jurisdiction found not to exist

This article considers three “unanswered questions” raised by R. (McConnell) v Registrar General for England and Wales (AIRE Centre Intervening) [2020] EWCA Civ. 559, which held that a trans man (with a Gender Recognition Certificate) who gave birth must be registered as “mother” on his child’s birth certificate. This article considers these questions to clearly situate McConnell within the context of the UK’s legal regimes concerning access to fertility treatment, gender recognition and legal parenthood in cases involving assisted reproduction. The article argues that clearly establishing the current legal position will provide the proper context to facilitate any subsequent legal reforms.

Sustainability is becoming a major strategic driver within the aviation industry, which has moved from providing primarily economic benefits to delivering the ‘triple bottom line’, including social and environmental impact as well as financial performance. Sustainable aviation is also being tracked by the International Civil Aviation Organisation (ICAO) Global Collation for Sustainable Aviation. Operations and Infrastructure is an important near-term opportunity to deliver sustainability benefits. Digital Technologies, Integrated Vehicle Health Management (IVHM) and Maintenance Repair and Overhaul (MRO) play a prominent role in implementing these benefits, with a particular focus on operational efficiencies. As part of this, the sustainable smart hangar of the future is a concept that is becoming more and more important in forming the future of the aviation industry. The Hangar of the Future is an excellent opportunity for innovation, combining the progress in manufacturing, materials, robotics and artificial intelligence technologies. Succeeding in developing a hangar with these characteristics will provide us with potential benefits ranging from reduced downtime and costs to improved safety and environmental impact. This work explores some of the key features related to the sustainable smart hangar of the future by discussing research that takes place in DARTeC’s (Digital Aviation Research and Technology Centre) hangar led by the IVHM Centre in Cranfield. Additionally, the paper touches on some longer-term aspirations.

The proto-Milky Way epoch forms the earliest stars in our galaxy and sets the initial conditions for the subsequent disk formation. Recent observations showed that the [$\alpha$/Fe] ratio among in situ metal-poor stars declined between [Fe/H] $=-3$ and $-1.3$ until it reached the lowest value ($\sim$0.25) and rose to the traditional value associated with the high-[$\alpha$/Fe] thick disk ($\sim$0.3) at [Fe/H] $\approx$ -1.0. It was suggested that the rise in [$\alpha$/Fe] could be caused by an increase in the star formation efficiency (SFE), known as the ‘simmering’ phase scenario. However, gas inflow also plays a vital role in shaping the star formation history and chemical evolution of galaxies, especially during the earliest epoch of the universe. We investigate this unexpected [$\alpha$/Fe]-rise with an experiment involving a galactic chemical evolution model. Our model has five free parameters: the mass of the initial reservoir of the cold interstellar medium (ISM) at birth, the frequency of Type Ia supernovae (SNe Ia), the cooling timescale of the warm ISM, the SFE, and the inflow rate of fresh gas. The last two free parameters were allowed to change after [$\alpha$/Fe] reached its lowest value, dividing the proto-Galaxy epoch into two phases. The models that reproduced the observed [Fe/H]-[$\alpha$/Fe]-track provided estimates for these fundamental parameters of the proto-Milky Way. We find that the rise in [$\alpha$/Fe] could also be caused by a large inflow of high-[$\alpha$/Fe] gas and conclude that the [$\alpha$/Fe]-rise could be a signature of the gas accretion that fuelled the formation of the Milky Way disk.

The interaction between deformable surfaces and oscillatory driving is known to produce complex secondary time-averaged flows due to inertial and elastic nonlinearities. Here, we revisit the problem of oscillatory flow in a cylindrical tube with a deformable wall, and analyse it under a long-wave theory for small deformations, but for arbitrary Womersley numbers. We find that the oscillatory pressure does not vary linearly along the length of a deformable channel, but instead decays exponentially with spatial oscillations. We show that this decay occurs over an elasto-visco-inertial length scale that depends on the material properties of the fluid and the elastic walls, the geometry of the system, and the frequency of the oscillatory flow, but is independent of the amplitude of deformation. Inertial and geometric nonlinearities associated with the elastic deformation of the channel drive a time-averaged secondary flow. We quantify the flow using numerical solutions of the perturbation theory, and gain insight by developing analytic approximations. The theory identifies a complex non-monotonic dependence of the time-averaged flux on the elastic compliance and inertia, including a reversal of the flow. Finally, we show that our analytic theory is in excellent quantitative agreement with the three-dimensional direct numerical simulations of Pande et al. (Phys. Rev. Fluids, vol. 8, no. 12, 2023, 124102).

Microplastics pollution is a widely recognized issue, although significant analytical challenges remain to be overcome in order to achieve a more comprehensive ecological understanding. The complex nature of this pollutant, with its variable physical and chemical properties, presents considerable challenges when it comes to establishing standardized methods for studying it. One crucial factor that influences its toxicity is particle size, yet even this parameter lacks a well-established framework, especially in the case of nanoplastics. Although the size range limits are already proposed in the literature, where the most acceptable values for microplastics are from 1 to 5,000 μm and for nanoplastics are from 1 to 1,000 nm, we propose narrowing these limits to 0.1–1,000 μm and 10–100 nm, respectively. We based our discussion on conceptual terminology, polymer structure and toxicity, highlighting the significance of accurately defining their size range. The standardization of these limits will allow the development of more efficient approaches to studying this pollutant, enabling a comprehensive understanding of its ecological consequences and potential risks.

To bring linguistic theory back in touch with commonplace observations concerning the resilience of language in use to language change, language acquisition and ungrammaticality, Pullum and colleagues have argued for a ‘model-theoretic’ theory of syntax. The present paper examines the implications for linguists working in standard formal frameworks and argues that, to the extent that such theories embrace monotonicity in syntactic operations, they qualify as model-theoretic under some minor modifications to allow for the possibility of unknown words.

Oloyede and colleagues advocate for updating haematological monitoring requirements for clozapine, arguing that current protocols overestimate the risk of clozapine-induced agranulocytosis. Their research suggests that stringent monitoring may unnecessarily limit access to clozapine, a crucial treatment for resistant schizophrenia. The editorial supports calls for international consensus to carefully weigh the pros and cons of relaxing monitoring guidelines while ensuring comprehensive care for patients.

Bioethics as a philosophical discipline deals with matters of life and death. How it deals with them, however, depends on the kind of life particular bioethicists focus on and the kind of value they assign to it. Natural-law ethicists and conservative Kantians emphasize biological human life regardless of its developmental stage. Integrative bioethicists also embrace nonhuman life if it can be protected without harming humans. Liberal and utilitarian moralists concentrate on life that is sentient and aware of itself, to the exclusion of biological existence devoid of these. Extinctionist and antinatalist philosophers believe that life’s value is negative and that its misery should be alleviated and terminated by not bringing new individuals into existence. As the last-mentioned approach reverses the idea of life’s positive value, it could be called oibethics.

Numerous differences exist between and within research projects related to assessment and operationalization of potentially traumatic events (PTEs) for youth, especially when measuring polyvictimization. However, few studies have systematically examined how polyvictimization measurement differences influence PTE’s relation to functioning. This study sought to address these knowledge gaps by conducting a secondary data multiverse replication (SDMR) to systematically (re)evaluate PTE polyvictimization measurement approaches. Participants included 3297 adolescents (Mage = 14.63; 50.59% female; 65.15% white) from the National Survey of Adolescents-Replication study who completed a structured interview on PTE exposure and emotional and behavioral health (i.e., posttraumatic stress and major depressive disorder, drug and alcohol use, and delinquency). Results indicated that PTE operationalizations using a count variable tended to demonstrate better model performance and prediction of youth at-risk of emotional and behavioral health challenges, compared to models using a binary (yes/no) PTE operationalization. Differences in model performance and prediction were less distinct between models examining multiple forms of a single type of PTE (e.g., maltreatment, community violence), compared to models examining multiple PTE types. These findings emphasize the importance of using multidimensional approaches to PTE operationalization and the need for more multiverse analyses to improve PTE evidence-based assessment.