Explore the vast range of titles available.

This article analyses the live Professional Darts Corporation (PDC) event to explore how contemporary sport spectacles are governed through affective and communicative forms of control. Drawing on Blackshaw and Coetzee’s (2020) concept of performative governmentality and Debord’s (1967) theory of the spectacle, it examines how spontaneity and participation are choreographed within a commercial event ecology. Based on ethnographic research conducted between 2016 and 2023, the study identifies a system of decentred control in which fans are both empowered and regulated. Building on Harper’s (2010) idea of communicative ontology, it argues that fans’ chants, costumes, songs, and humour constitute the event’s affective texture while serving the PDC’s and media broadcasters aims. The analysis reveals that control operates through atmosphere rather than authority, transforming spectators into co-creators of value. The article concludes by highlighting implications for event managers seeking to design participatory yet ethically governed live experiences.

We report the first observations of negative intracloud (IC) dart‐stepped leaders accompanied by regular trains of microsecond‐scale pulses, simultaneously detected by shielded broadband magnetic loop antennas and the radio telescope Low Frequency Array (LOFAR). Four investigated pulse trains occurred during complicated IC flashes on 18 June 2021, when heavy thunderstorms hit the Netherlands. The pulses within the trains are unipolar, a few microseconds wide, and with an average inter‐pulse interval of 5–7 μs. The broadband pulses perfectly match energetic, regularly distributed, and relatively isolated bursts of very high frequency sources localized by LOFAR. All trains were generated by negative dart‐stepped leaders propagating at a lower speed than usual dart leaders. They followed channels of previous leaders occurring within the same flash several tens of milliseconds before the reported observations. The physical mechanism remains unclear as to why we observe dart‐stepped leaders, which show mostly regular stepping, emitting energetic microsecond‐scale pulses. Plain Language Summary Lightning phenomena inside thunderclouds can be explored using their electromagnetic radiation. To study these processes at small temporal and spatial scales, we combine broadband magnetic loop antennas with the Low Frequency Array (LOFAR) radio telescope. Measurements of broadband antennas acquired during a severe Dutch thunderstorm showed pulse sequences composed of tens microsecond‐scale unipolar pulses, which were surprisingly regularly distributed. Such regular pulse trains have been rarely reported from previous observations. When we thoroughly lined up the timestamps of both simultaneously measuring observational systems, we found that the regular broadband pulses perfectly match with localized isolated bursts of energetic very high frequency radiation detected by LOFAR. The 3D mapping of the radio sources of these bursts allowed us to place the investigated events into the context of the parent intracloud (IC) lightning flash. The results revealed negative IC dart leaders, which propagated along the preconditioned channels originally formed by previous positive or negative IC leaders. Some of these dart leaders then exhibited unusual stepping manifested by the observed regular pulses. We assume that a favorable combination of the conductivity of preexisting lightning channels and the strength of the ambient electric field inside thunderclouds might be needed to trigger this unusual stepping. Key Points We observed intracloud negative dart‐stepped leaders producing regular trains of broadband electromagnetic microsecond‐scale pulses Very High Frequency sources follow channels of previous leaders occurring within the same flash tens of milliseconds before the reported observations Conductivity of decaying channels and strength of the ambient electric field might act together to trigger this unusual stepping process

One of the challenges in deep learning involves discovering the optimal architecture for a specific task. This is effectively tackled through Neural Architecture Search (NAS). Neural Architecture Search encompasses three prominent approaches—reinforcement learning, evolutionary algorithms, and gradient descent—that have demonstrated noteworthy potential in identifying good candidate architectures. However, approaches based on reinforcement learning and evolutionary algorithms often necessitate extensive computational resources, requiring hundreds of GPU days or more. Therefore, we confine this work to a gradient-based approach due to its lower computational resource demands. Our objective encompasses identifying the optimal gradient-based NAS method and pinpointing opportunities for future enhancements. To achieve this, a comprehensive evaluation of the use of four major Gradient descent-based architecture search methods for discovering the best neural architecture for image classification tasks is provided. An overview of these gradient-based methods, i.e., DARTS, PDARTS, Fair DARTS and Att-DARTS, is presented. A theoretical comparison, based on search spaces, continuous relaxation strategy and bi-level optimization, for deriving the best neural architecture is then provided. The strong and weak features of these methods are also listed. Experimental results for comparing the error rate and computational cost of these gradient-based methods are analyzed. These experiments involved using bench marking datasets CIFAR-10, CIFAR-100 and ImageNet. The results show that PDARTS is better and faster among the examined methods, making it a potent candidate for automating Neural Architecture Search. By effectively conducting a comparative analysis, our research provides valuable insights and future research directions to address the criticism and gaps in the literature.

This study analyzes the two‐dimensional speed profiles of 107 stepped leaders and 93 dart leaders recorded by high‐speed cameras in Utah (USA), together with data from lightning location system. The results shows that the final and average speed of the stepped leader has a very strong (R = 0.82) and strong (R = 0.71) correlation with the peak current of the return stroke. It also shows that 91% of the stepped leaders increased their speed near the ground (average increase of 69%). The same analysis for dart leaders shows weak correlation with the peak current of the prospective return stroke (R = 0.39 to average speed and R = 0.28 to final speed). This paper briefly discusses why peak current is better correlated with final speed than with the average speed, and why stepped leaders exhibit a significant correlation, while dart leaders do not. Plain Language Summary This study looks at how fast stepped leaders and dart leaders of lightning flashes propagate from the cloud base to ground, using high‐speed camera videos and data from a lightning location system. The results show that the final and average speed of the leaders are well correlated to the return stroke current, the return stroke current being more closely related to the final speed than the average speed. In contrast, dart leaders showed a weak correlation between their speed and the return stroke current. It also shows that most stepped leaders sped up as they got closer to the ground. Key Points The return stroke peak current is better correlated with final speed than with the average speed of the stepped leader No significant correlation was found between dart leaders speed and stroke peak current The stepped leaders increase their propagation speed near the ground

The concepts of explorer, expedition, and the combination of the two into the myth of the explorer have been integral par ts of Western mentality for more than 200 years. Here we briefly outline the colonial origins of these ideas, and use this crystallised understanding of the explorer myth to consider how African palaeoanthropology in the 20th century and up to the present continues to carry many of these biased, outdated over tones - some more over tly than others. We examine how Raymond Dar t and the discovery of the Taung Child were situated and storied within this explorer narrative. We also expand on how these outdated concepts persist in determining which scientific approaches and outcomes are valued and which are not, which in turn has perpetuated extractive approaches to palaeoanthropology and the marginalisation of Indigenous scientists. This is especially notable in fieldwork practices which, to this day, embody the explorer myth's deeply problematic colonial ideals of Western, masculine moral and cultural superiority. By understanding the mindset behind the discovery and repor ting of Dar t's work on the Taung Child, we can better understand why it still holds such sway in palaeoanthropology today, and propose impor tant practical and cultural disciplinary changes that will allow us to move beyond these colonial and masculine ideas in a manner that creates a more equitable future for all scholars.

With the rapid development of neural architecture search (NAS), researchers found powerful network architectures for a wide range of vision tasks. Like the manually designed counterparts, we desire the automatically searched architectures to have the ability of being freely transferred to different scenarios. This paper formally puts forward this problem, referred to as NAS in the wild, which explores the possibility of finding the optimal architecture in a proxy dataset and then deploying it to mostly unseen scenarios. We instantiate this setting using a currently popular algorithm named differentiable architecture search (DARTS), which often suffers unsatisfying performance while being transferred across different tasks. We argue that the accuracy drop originates from the formulation that uses a super-network for search but a sub-network for re-training. The different properties of these stages have resulted in a significant optimization gap, and consequently, the architectural parameters “over-fit” the super-network. To alleviate the gap, we present a progressive method that gradually increases the network depth during the search stage, which leads to the Progressive DARTS (P-DARTS) algorithm. With a reduced search cost (7 hours on a single GPU), P-DARTS achieves improved performance on both the proxy dataset (CIFAR10) and a few target problems (ImageNet classification, COCO detection and three ReID benchmarks). Our code is available at https://github.com/chenxin061/pdarts.

The dissonant development of positive and negative lightning leaders is a central question in atmospheric electricity. It is also the likely root cause of other reported asymmetries between positive and negative lightning flashes, including the ones regarding: stroke multiplicity, recoil activity, leader velocities, and emission of energetic radiation. In an effort to contrast lightning leaders of different polarities, we highlight the staggering differences between two rocket‐triggered lightning flashes. The flash beginning with upward positive leaders exhibits an initial continuous current stage followed by multiple sequences of dart leaders and return strokes. On the other, in its opposite‐polarity counterpart, the upward development of negative leaders is by itself the entire flash. As a result, the flash with negative leaders is faster, briefer, transfers less charge to the ground, has lower currents, and smaller spatial extent. We conclude by presenting a discussion on the three fundamental leader propagation modes. Plain Language Summary Lightning flashes that carry positive and negative charges are completely different. In this article, we report on lightning triggered by launching a rocket tethered to the ground toward an electrified cloud. The staggering differences between positive and negative flashes are exposed by a three‐dimensional radio location system and by the current transferred to ground via the trailing wire. Key Points Triggered flashes with positive and negative leaders are contrastingly different with the latter being faster, briefer, and more compact The channel behind triggered positive leaders decays engendering dart leaders and return strokes, which is unparalleled in the negative case Average conductivity is higher in the negative leader channel despite the lack of return strokes and the lower charge transferred to ground

Recoil leaders develop in lightning flash decayed channels. The propagation of a recoil leader depends on the charges stored at its tip and the conductivity of the decayed channel. When the recoil leader propagates over the entire channel, a subsequent return stroke happens. Recoil leaders very often cease propagating before they reach the ground, that is, only part of the decayed channel is reionized. The present work aims to analyze the herein named secondary recoil leader that connect with the primary recoil leaders and cause them to start propagating again. We believe that the secondary recoil leader injects additional charge into the primary recoil leader, allowing the recoil leader reionize the whole decayed channel of the lightning flash. High‐speed videos analysis of upward lightning flashes shows that secondary recoil leaders play an important role on the formation and progression of dart leaders/subsequent return strokes. Plain Language Summary The recoil leader is a phenomenon that occurs in all types of lightning flashes (upward, downward and intracloud flashes). They arise in the remnants of decayed channels of positive leaders, partially or completely rebuilding these channels. The recoil leaders are responsible for some physical processes observed in lightning flashes. Thus, understanding how these physical processes originate is of significant importance. This work presents the role of secondary recoil leaders (recoil leaders that connect to preexisting recoil leaders) in the integral reconstruction of the decayed channels of the analyzed lightning flashes. Key Points Use of high‐speed cameras to study recoil leaders in upward lightning flashes Secondary recoil leaders boost the development of previous recoil leaders Secondary recoil leaders likely influence the development of dart leaders/subsequent return strokes