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The dynamics of thin viscous liquid films flowing down an inclined wall under gravity in the presence of an upward flowing high-speed air stream is considered. The air stream induces nonlinear waves on the interface and asymptotic solutions are developed to derive a non-local evolution equation forced by the air pressure which is obtained analytically, and incorporating a constant tangential stress. Benney equations in the capillary (strong surface tension) and inertio-capillary regimes are derived and studied. The air stream produces Turing-type short wave instabilities in sub-critical Reynolds number regimes that would be stable in the absence of the outer flow. Extensive numerical experiments are carried out to elucidate the rich dynamics in the above-mentioned short-wave regime. The stability of different branches of solutions of non-uniform steady states is carried out, along with time-dependent nonlinear computations that are used to track the large-time behaviour of attractors. A fairly complete picture of different solution types are categorised in parameter space. The effect of the Reynolds number on the wave characteristics in the inertio-capillary regime is also investigated. It is observed that, for each value of the slenderness parameter $\delta$, there exists a critical Reynolds number $R_c$ above which the solutions become unbounded by encountering finite-time singularities. Increasing the air speed significantly decreases $R_c$, making the system more prone to large amplitude singular events even at low Reynolds numbers when the system would have been stable in the absence of the air stream.
The current study examined how early smartphone ownership impacts parent-child informant discrepancy of youth internalizing problems during the transition to adolescence. We used four waves of longitudinal data (Years 1–4) from the Adolescent Brain Cognitive Development (ABCD; Baseline N = 11,878; White = 52.0%, Hispanic = 20.3%, Black = 15.0%, Asian = 2.1%, Other = 10.5%; Female = 47.8%). Across the full sample, significant parent-child informant discrepancy, such that parents underestimated child reports, appeared at Year 2 (Mage = 12.0) and increased across the remainder of the study (b = −0.21, SE = .042, p < .001, 95%CI [−.29, −.23]). Further, multi-group models indicated that significant parent-child informant discrepancy emerged in the years following initial smartphone acquisition, whereas youth who remained non smartphone owners did not demonstrate such a pattern. Moreover, this discrepancy grew with additional years of smartphone ownership. This study contributes to the ongoing discourse on adolescent smartphone use and mental health by documenting a novel, longitudinally observed risk to timely parental detection of mental health problems by early smartphone ownership.
An analytical theory is presented for linear, local, short-wavelength instabilities in swirling flows, in which axial shear, differential rotation, radial thermal stratification, viscosity and thermal diffusivity are all taken into account. A geometrical optics approach is applied to the Navier–Stokes equations, coupled with the energy equation, leading to a set of amplitude transport equations. From these, a dispersion relation is derived, capturing two distinct types of instability: a stationary centrifugal instability and an oscillatory, visco-diffusive McIntyre instability. Instability regions corresponding to different axial or azimuthal wavenumbers are found to possess envelopes in the plane of physical parameters, which are explicitly determined using the discriminants of polynomials. As these envelopes are shown to bound the union of instability regions associated with particular wavenumbers, it is concluded that the envelopes correspond to curves of critical values of physical parameters, thereby providing compact, closed-form criteria for the onset of instability. The derived analytical criteria are validated for swirling flows modelled by a cylindrical, differentially rotating annulus with axial flow induced by either a sliding inner cylinder, an axial pressure gradient or a radial temperature gradient combined with vertical gravity. These criteria unify and extend, to viscous and thermodiffusive differentially heated swirling flows, the Rayleigh criterion for centrifugally driven instabilities, the Ludwieg–Eckhoff–Leibovich–Stewartson criterion for isothermal swirling flows and the Goldreich–Schubert–Fricke criterion for non-isothermal azimuthal flows. Additionally, they predict oscillatory modes in swirling, differentially heated, visco-diffusive flows, thereby generalising the McIntyre instability criterion to these systems.
Amid China’s goals to reach peak carbon emissions before 2030 and achieve carbon neutrality by 2060, along with its ecological civilization agenda, the synergy between the digital economy (DE) and environmental quality (EQ) in Chinese cities has become increasingly vital. Using panel data from 285 cities between 2016 and 2021, this study constructs an integrated framework to examine the level of coordinated development between the DE and EQ, measured through the coupling coordination degree (CCD) that captures the strength and harmony of their interaction. It further analyses spatial–temporal heterogeneity and influencing factors. The results reveal: (1) both the DE and EQ have improved steadily, with the CCD rising to a moderate level and showing clear spatial clustering; and (2) economic development, educational investment and industrial upgrading boost the CCD, whereas average years of education and government intervention may hinder it. Additionally, economic development and industrial upgrading have positive spatial spillovers, and a threshold effect of government intervention is observed.
The Journal of Management and Organization (JMO) is celebrating its 30th birthday, which is a significant event given how the journal has shaped and influenced global management research and practice. As part of the commemorative activities this perspective article aims to highlight how the journal has contributed to the development of several sub-management themes. Each theme is analysed in terms of articles published in the journal in terms of establishing existing knowledge then explaining future research ideas. This helps to solidify the journal’s reputation and standing in the field in order to foster more management research that contributes to both theory and practice. Novel social and business approaches to future organizational and manager’s needs are addressed. This will inspire more meaningful management engagement in order to further support the evolution of management research.
Insect pupae change morphologically (e.g., pigmentation of eyes, wings, setae and legs) during the intrapuparial period. Knowledge on the physiological age of pupae and their emergence are important parameters for the control of agriculturally important Tephritid flies. Traditional methods for determining age require dissecting the puparium, thus killing the specimen. Therefore, non-invasive and more ethical methods to determine physiological age are needed, especially if individual pupae are followed throughout their development. Furthermore, machine learning methods can be employed to detect pupal age, thereby reducing human-bias. Here, we studied the intrapuparial development of the Mexican fruit fly, Anastrepha ludens (Diptera: Tephritidae), using non-invasive near-infrared (NIR, 850–1100 nm) images. We photographed pupae and subsequently analysed the images with machine learning algorithms. The intrapuparial period lasted between 17 and 19 days at a constant temperature of 26°C, and 75–80% relative humidity. No visible structures were observed between days 1 and 3. The phanerocephalic pupa was observed on day 4. The darkening of the eyes began on day 12. Wing pigmentation occurred on days 13 and 14, and the legs and setae on the thorax became melanized on day 15. A convolutional neural network correctly identified the physiological age range of intrapuparial development stages with an average accuracy of 71.77%. This model using NIR imaging allows the determination of a physiological age range without arresting the development of the pupae, and an estimation of the viability of pupae without waiting for the emergence of the adult.
Public art is fundamental in the shaping of a city’s identity: in the city of Bologna’s case, this identity is inextricably tied to the Resistance. The presence or absence of women in monumental commemorations, then, becomes a way to either include or exclude them from this shared identity. By centring its analysis on the monuments dedicated to the Resistance’s fallen erected since 1945, this article will utilise the case study of Irma Bandiera to analyse women’s presence within the commemorative topography of the city. Through the study of two monuments, the Monumento Ossario ai Caduti Partigiani and the Memoriale alle 128 partigiane cadute, this article will also highlight the role of the local community in the creation of a shared and representative identity.
Paleontology is facing an ethical crisis related to its long history of extractive practices, including a practice now referred to as ‘parachute science.’ In this paper, I provide diagnostic criteria for identifying parachute science and illustrate them using the high-profile example of a Brazilian dinosaur fossil, Irritator challengeri, acquired by a German museum under dubious conditions. I use this case study to identify three types of harm resulting from parachute science, showing how they can be understood as a case of distributive epistemic injustice. I conclude by using this framework to point toward more ethical paleontological practices.
In the United States, in the second half of the nineteenth century, the reforming institutions of the horse-drawn-carriage trade prescribed descriptive geometry to their workshops in order to modernize the drawing process for modern carriages. This injunction, institutionally supported by the builder’s national association, professional newspapers, and education, was part of a wider movement to organize production at a time when the carriage trade was booming. In order to facilitate the circulation of theoretical knowledge within workshops that were reluctant to mathematize their environment, two trade journals translated, in the space of a few years, and on three occasions (once by one journal and twice by the other), the same French treatise on descriptive geometry written by a Parisian carriage woodworker. This paper highlights the process of creation of a mathematical translation in a professional environment. It emphasizes the significant role of the industrial and technical context that influenced the choice of translators, the writing style, and the speed with which a translation was produced and published. In the case of mathematical content that did not belong to the common culture of the trade, international circulation allowed for the direct transfer of knowledge from one national industry to another, without relying on academic sources as intermediaries.
The mandible is crucial for human physiological functions, as well as facial esthetics and expressions. The mandibular reconstruction surgery has dual challenges of restoration of both facial form and physiological function, which demands high precision in positioning and orientation of the bone graft. The traditional manual surgery heavily relies on surgeon’s experience. Although the computer image-guided surgery improves the positioning accuracy, the manual manipulation is still difficult to achieve precise spatial orientation of objects, resulting in unsatisfactory intraoperative execution of preoperative surgical design. This paper integrates computer image navigation and robotic technology to assist mandible reconstruction surgery, which empowers surgeons to achieve precise spatial localization and orientation adjustment of bone grafts. The kinematic analysis is conducted, and an improved Iterative Closest Point (ICP) algorithm is proposed for spatial registration. A novel hand-eye calibration method for multi-arm robot and spatial registration of free bone blocks are proposed. The precision experiment of the image-guided navigation and the animal experiments are carried out. The impact of registration point numbers on spatial registration accuracy is analyzed. The results show the feasibility of the robot-assisted navigation for mandibular reconstruction surgery. The robotic system can improve the orientation accuracy of bone blocks to enhance the effectiveness of surgery.
The taxonomic status of Sphincteristomum Oshmarin, Mamaev & Parukhin, 1961 (sensu lato) and Lobatotrema Manter, 1963 is controversial due to overlap/confusion in distinctive diagnostic characteristics for each genus and morphological/allometric ambiguity among some of their representatives and/or within records of the same species. To address these in-depth, morphological descriptions, molecular characterizations, and species delimitation analyses were conducted using a combination of comparative morphology, molecular phylogeny, multivariate analyses, and host-parasite data. Following a comprehensive review, a refined restricted concept of Sphincteristomum and Lobatotrema is proposed. Representatives of Lobatotrema comprise Lobatotrema aniferum Manter, 1963 (sensu lato) and the morphologically/phylogenetically distinct Lobatotrema dronenin. sp. Representatives of Sphincteristomum (sensu stricto) include Sphincteristomum acollum Oshmarin, Mamaev & Parukhin, 1961, and Sphincteristomum nikolaevi Parukhin, 1970. The taxonomic status of Sphincteristomum mediterraneae Abid-Kachour, Mouffok & Boutiba, 2013 is problematic based on its intermediate taxonomic position between the Megaperinae Manter, 1934 and the Schistorchiinae Yamaguti, 1942. Molecular datasets are employed in an attempt to delineate and interpret more phylogenetic relationships among schistorchiines in light of differences in oral sucker nature, oral sucker shape, and oral sphincter shape. Distributions of schistorchiines in the Indo-West Pacific are discussed. Testes arrangement as a characteristic in this group and glandular components within a muscular oral sucker are presented. We comment on the close phylogenetic relationship between members of the Schistorchiinae and the Megaperinae.
Since the escalation of hostilities in Gaza in October 2023, the health care system has been overwhelmed by mass casualties, infrastructure damage, and supply shortages. Amid these conditions, septic amputations have emerged as a desperate, life-saving measure for patients with severe limb wound infections. This article examines the rise of such procedures, drawing from contextual analysis and firsthand cases at Al-Aqsa Martyrs’ Hospital. It also highlights doctors’ observation of how delayed access to care, lack of sterile tools, antibiotic shortages, and multidrug-resistant infections have often made limb salvage impossible. These amputations, while medically necessary, reflect the collapse of trauma care and underscore the urgent need for adaptable humanitarian intervention, standards, and call for the protection of health care facilities and services continuity.
The global C0 linearization theorem on Banach spaces was first proposed by Pugh [26], but it requires that the nonlinear term is globally bounded. In the present paper, we discuss global linearization of semilinear autonomous ordinary differential equations on Banach spaces assuming that the linear part is hyperbolic (including contraction as a particular case) and that the nonlinear term is only Lipschitz with a sufficiently small Lipschitz constant. To overcome the difficulties arising in this problem, in this paper, we rely on a splitting lemma to decouple the hyperbolic system into a contractive system along the stable manifold and an expansive system along the unstable manifold. We then construct a transformation to linearize a contractive/expansive system, which is defined by the crossing time with respect to the unit sphere. To demonstrate the strength of our result, we apply our results to a nonlinear Duffing oscillator without external excitation.
We introduce a novel unsteady shear protocol, which we name rotary shear (RS), where the flow and vorticity directions are continuously rotated around the velocity-gradient direction by imposing two out-of-phase oscillatory shears (OSs) in orthogonal directions. We perform numerical simulations of dense suspensions of rigid non-Brownian spherical particles at volume fractions ($\phi$) between 0.40 and 0.55, subject to this new RS protocol, and compare with the classical OS protocol. We find that the suspension viscosity displays a similar non-monotonic response as the strain amplitude ($\gamma _0$) is increased: a minimum viscosity is found at an intermediate, volume-fraction-dependent strain amplitude. However, the suspension dynamics is different in the new protocol. Unlike the OS protocol, suspensions under RS do not show absorbing states at any $\gamma _0$ and do not undergo the reversible–irreversible transition: the stroboscopic particle dynamics is always diffusive, which we attribute to the fact that the RS protocol is inherently irreversible due to its design. To validate this hypothesis, we introduce a reversible-RS (RRS) protocol, a combination of RS and OS, where we rotate the shear direction (as in RS) until it is instantaneously reversed (as in OS), and find the resulting rheology and dynamics to be closer to OS. Detailed microstructure analysis shows that both the OS and RRS protocols result in a contact-free, isotropic to an in-contact, anisotropic microstructure at the dynamically reversible-to-irreversible transition. The RS protocol does not render such a transition, and the dynamics remains diffusive with an in-contact, anisotropic microstructure for all strain amplitudes.