Laser-driven plasma wakefield acceleration (LWFA) offers exceptionally high acceleration gradients and can produce high-brightness electron beams. However, the laser-to-electron energy conversion efficiency typically remains limited to a few percent. Theoretically, the self-mode transition from LWFA to beam-driven plasma wakefield acceleration (PWFA) provides a pathway for fully utilizing the laser energy. Here, we demonstrate the single-stage LPWFA (hybrid LWFA–PWFA) scheme, validated through comparative experiments using a 300 TW tightly focused laser interacting with sub-critical density nitrogen gas targets. The experiments produce an electron beam with charge of approximately 31 nC above 6 MeV and approximately 116 nC above 2 MeV. The laser-to-electron energy conversion efficiency is approximately 6.1% (>6 MeV) and 16.4% (>2 MeV), respectively. Particle-in-cell simulations confirm that the single-stage LPWFA mechanism depletes the laser energy and enables continual electron injection. This high-charge, multi-MeV electron beam has great value in the generation of high-brightness $\unicode{x3b3}$-rays and high-flux neutron sources.

In the years 1803–1807, a dramatic triple murder case in Shouzhou, Anhui, convulsed officialdom in the Jiangnan region and drove the Jiaqing emperor to exasperation. At a time when many in power felt a sense of crisis as “High Qing” imperial ambitions receded, each stone turned over in this meandering investigation revealed another source of anxiety fitted to the age: incest, poisoning, negligent and corrupt officials, amoral and abusive local gentry, misbehaving yamen runners, pettifogging litigators, and, to top it all off, deadly serious rumors of a subversive opera. This article traces the investigations into both the murders and the theater rumor. What made the former so convoluted and vexing, while the latter was alarming yet easier to resolve? Surprisingly, the Imperial Household’s carefully cultivated relationship with the theater world of Jiangnan realized, in miniature, a level of state–society coordination Qing rulers wished for but which often escaped them elsewhere.

From spider dances to human language, multimodality is ubiquitous in natural communication systems. Much scholarship has been devoted to investigating why multimodality evolved and the role it plays in communication. Here, we highlight the role of multimodality in safeguarding the most fundamental prerequisite of all functioning, extant communication systems: honesty. We begin by introducing the arms race between honesty and deception in natural communication systems, and the critical role socially-mediated controls can play in maintaining signal honesty when classic, intrinsic costs are not sufficient. We next introduce three ways by which multimodality buffers signal honesty by 1) providing insurance against signal unreliability in dynamic environments, 2) forming an honest, multimodal gestalt with which to cross-validate signal honesty, and 3) increasing signal complexity, making the entire signal harder to fake. We then discuss the case of highly cooperative societies, with human language emphasized, and argue that signal honesty is important especially in complex and cooperative societies wherein the need to cooperate and be accepted as part of the group may supersede honesty. Finally, we propose future directions wherein human and non-human communication research could expand beyond the well trodden realms of competition and mate attraction to investigate the role of multimodality and honesty in cooperative, “cheap” signals, and emphasize the importance of drawing from both the human and non-human literatures in investigating the forces that have shaped the evolution of communication.

Italy has long been a textbook case of government instability. Against this backdrop, the exceptional longevity of the Meloni government marks a clear reversal. However, the cabinet is ruling under the same institutional constraints that once made Italian governments short-lived and fragile. In this study, I seek to make sense of this exceptional stability tracing how potential stabilizing mechanisms have jointly operated across all the stages of the coalition life-cycle framework. Stability, I argue, has resulted from the convergence of multiple stabilizing mechanisms that have seldom aligned simultaneously in the Italian context. The main lesson from this deviant case lies in a paradox: Italy's most durable government in decades is promoting a constitutional reform intended to enhance stability, even though cohesive and disciplined coalitions can already achieve it without altering institutional rules.

We investigate heat kernel-based and other p-energy norms ($1\lt p\lt\infty$) on bounded and unbounded metric measure spaces, in particular, on nested fractals and their blow-ups. With the weak-monotonicity properties for these semi-norms, we generalise the celebrated Bourgain–Brezis-Mironescu (BBM) type characterisation for $p\neq2$. When the underlying space admits a heat kernel satisfying the sub-Gaussian estimates, we establish the equivalence of various p-energy semi-norms and weak-monotonicity properties, and show that these weak-monotonicity properties hold when $p=2$ (that is the case of Dirichlet form). Our paper’s key results concern the equivalence and verification of various weak-monotonicity properties on fractals. Consequently, many classical results on p-energy norms hold on nested fractals and their blow-ups, including the BBM type characterisation and Gagliardo-Nirenberg inequality.

The effects of the main parameters of the helicon plasma sources on the volume process of the negative ion production mechanism are investigated. Using COMSOL Multi-Physics software, a helicon plasma source as a source driver of a negative ion source is modelled in three dimensions. In this work, it is considered that the helicon plasma source employs a Nagoya-type antenna at an operational frequency of 13.56 MHz. The influences of the static magnetic field variation, applied radio frequency power and injected gas pressure on electron/plasma density, electron temperature and vibrationally excited molecular density are studied. Variations of the static magnetic field in a range of 0.01–0.08 T, Radio Frequency (RF) power in a range of 800–6000 W and gas pressure range of 0.3–1.5 Pa indicate that the maximum electron (plasma) density is increased in all three cases; nevertheless, the electron temperature and maximum density of the vibrationally excited molecules is increased just by RF power increment. For the pressure of 0.3 Pa, it is found that using a proper coil configuration, the electron density and the vibrationally excited molecular density will be increased without the magnetic field (applied DC power) increment and RF power increment.

Recent research has identified numerous distinctive architectural complexes in the central and western Maya Lowlands. Characterized by concentric arrays of low structures, these assemblages are consistent with Conquest-period descriptions of central Mexican marketplaces. Predominantly dating to the Classic period (ca. a.d. 250–900), they are also remarkably similar to the East Plaza of Tikal and the Chiik Nahb complex at Calakmul, both interpreted as markets based on multiple lines of evidence. The low, narrow, elongated mounds arranged in concentric circles or rectangles are likely remnants of platforms that once supported perishable stalls for displaying goods, with the intervening aisles functioning as walkways. Associated major structures and annexed courtyards may have accommodated administrative authorities or served as storage facilities. Stone altars and shrine remains within these complexes, along with the occasional presence of ballcourts and ceremonial buildings, align with well-documented religious and ritual aspects of Mesoamerican trade. While further research will undoubtedly detect more of these nested constructions, their distribution appears to be geographically limited. Since the available evidence strongly suggests that they represent a regional variant of ancient Maya built markets, this study also explores their distribution in relation to major trade routes, environmental constraints, and regional economic specializations.

Between 2021 and 2025, national media gave attention to federal court cases and legislation that established new policies for increasing the compensation of college athletes. Foremost was “NIL,” acronym for the “Name-Image-Likeness” payment guidelines. Although NIL was hailed as a “whole new ball game” for students as paid athletes, our research tempers news coverage by drawing from historical findings about trends and traditions in college sports practices and policies. Compensation and commercialization in American intercollegiate athletics—and issues of the rights of college students and the governance of college sports—have been central to intercollegiate athletics from their founding to the present. An enduring legacy is an “American Dilemma” in the balancing of academic and business principles in the education of collegiate student athletes and conduct of varsity sports programs.

We consider general discrete-time multitype branching processes on a countable set X. According to these processes, a particle of type $x\in X$ generates a random number of children and chooses their type in X, not necessarily independently nor with the same law for different parent types. We introduce a new type of stochastic ordering of multitype branching processes, generalising the germ order introduced by Hutchcroft, which relies on the generating function of the process. We prove that given two multitype branching processes with laws ${\boldsymbol{\mu}}$ and ${\boldsymbol{\nu}}$ respectively, with ${\boldsymbol{\mu}}\ge{\boldsymbol{\nu}}$, then in every set where there is survival according to ${\boldsymbol{\nu}}$, there is also survival according to ${\boldsymbol{\mu}}$. Moreover, in every set where there is strong survival according to ${\boldsymbol{\nu}}$, there is also strong survival according to ${\boldsymbol{\mu}}$, provided that the supremum of the global extinction probabilities for the ${\boldsymbol{\nu}}$ process, taken over all starting points x, is strictly smaller than 1. New conditions for survival and strong survival for inhomogeneous multitype branching processes are provided. We also extend a result of Moyal which claims that, under some conditions, the global extinction probability for a multitype branching process is the only fixed point of its generating function, whose supremum over all starting coordinates may be smaller than 1.

With the increasing application of artificial intelligence and autonomy in cyberspace, there is little doubt that “autonomous cyber capabilities” (ACC) – software agents that are programmed to carry out specific tasks through cyberspace without real-time human control or oversight – will be deployed in future armed conflicts. Yet, ACC’s lack of real-time human control and the risk of unpredictable, unreliable and unexplainable behaviour raise important concerns as to their use in compliance with international humanitarian law (IHL). This article explores whether due diligence may be a valuable framework to mitigate the risks associated with ACC and avoid unintended violations of IHL. Notably, it contends that due diligence is a chapeau obligation for several IHL norms that require States to undertake all appropriate measures to ensure the development and use of ACC in compliance with IHL, and it provides examples of diligent measures that States shall adopt.

Meta-analysis synthesizes evidence from multiple randomized clinical trials and informs evidence-based practices across various medical domains. Recently, causally interpretable meta-analysis has been proposed and applied to treatment evaluations for target populations, requiring individual participant data (IPD). Standard meta-analysis assumes transportability or exchangeability of a (conditional) relative effect (such as relative risk or odds ratio), which may be violated when the relative effects are correlated with the baseline risks across clinical trials. In addition, the weighted average of some study-specific effect measures such as the (log) odds ratios or the (log) hazard ratios is non-collapsible and does not correspond to any target population. Furthermore, when the randomization ratios between treated versus untreated arms vary across trials, confounding bias may occur. To address these challenges, we propose a causal meta-analysis (CMA) framework using only aggregated data, enabling causally interpretable and accurate estimation for different target populations. The CMA adjusts its weights for treatment effect across various target populations, including the average treatment effect (ATE), the ATE on the treated (ATT) population, the ATE on the control (ATC) population, and the ATE in the overlap (ATO) population. Mathematically, we discover the connection between traditional meta-analysis estimators and CMAs. For example, the Mantel–Haenszel weighted meta-analysis is equivalent to the CMA with ATO.

Jack Kemp’s ascent from cast-off professional football player to conservative national figure requires understanding how the phases of his athletic career, which he filtered through his on-field experiences, shaped his unorthodox hybridity. He was in many ways a standard small-government conservative advocating the tenets of the technocratic Sunbelt New Right, but one who took surprisingly progressive stands on issues of labor and race very much at odds with developing Republican orthodoxy.