This paper presents the effects of radio frequency interference (RFI) mitigation on a radio telescope’s sensitivity and beam pattern. It specifically explores the impact of subspace-projection mitigation on the phased array feed (PAF) beams of the Australian SKA Pathfinder (ASKAP) telescope. The goal is to demonstrate ASKAP’s ability to make science observations during active RFI mitigation. The target interfering signal is a self-generated clock signal from the digital receivers of ASKAP’s PAF. This signal is stationary, so we apply the mitigation projection to the beamformer weights at the beginning of the observation and hold them fixed. We suppressed the unwanted narrowband signal by 31 dB, to the noise floor of an 880 s integration on one antenna, with a typical degradation in sensitivity of just 1.5%. Sensitivity degradation over the whole 36 antenna array of 3.1% was then measured via interferometric assessment of system equivalent flux density (SEFD). These measurements are in line with theoretical calculation of noise increase using the correlation of the beam weights and RFI spatial signature. Further, degradation to the main beam’s gain is $\pm$ 0.4% on average at the half-power point, with no significant change to the gain in the first sidelobe and no variation during extended observations; also consistent with our modelling. In summary, we present the first demonstration of mitigation via spatial nulling with PAFs on a large aperture synthesis array telescope and assess impact on sensitivity and beam shape via SEFD and holography measurements. The mitigation introduces smaller changes to sensitivity than intrinsic sensitivity differences between beams, does not preclude high dynamic range imaging and, in continuum 1 MHz mode, recovers an otherwise corrupted holography beam map and usable astronomical source correlations in the RFI-affected channel.

We consider the problem of parameter estimation for the superposition of square-root diffusions. We first derive the explicit formulas for the moments and auto-covariances based on which we develop our moment estimators. We then establish a central limit theorem for the estimators with the explicit formulas for the asymptotic covariance matrix. Finally, we conduct numerical experiments to validate our method.

A high-energy picosecond 355 nm ultraviolet (UV) laser operating at 100 Hz was demonstrated. A 352 mJ, 69 ps, 1064 nm laser at 100 Hz was realized firstly by cascaded regenerative, laser diode end-pumped single-pass and side-pumped main amplifiers. The stimulated Raman scattering-based beam shaping technique, thermally induced birefringence compensation and 4f spatial filter-image relaying systems were used to maintain a relatively homogeneous beam intensity distribution during the amplification process. By using lithium triborate crystals for second- and third-harmonic generation (THG), a 172 mJ, approximately 56 ps, 355 nm UV laser was achieved with a THG conversion efficiency of 49%. To the best of our knowledge, it is the highest pulse energy of a picosecond 355 nm UV laser so far. The beam quality factor ${M}^2$ and pulse energy stability were ${M}_x^2$=3.92, ${M}_y^2$=3.71 and root mean square of 1.48%@3 hours. This laser system could play significant roles in applications including photoconductive switch excitation, laser drilling and laser micro-fabrication.

In this article, I offer a historical analysis of how bankers in Luxembourg came to be important service providers to borrowers in the Belgian Congo and Apartheid South Africa. I demonstrate how a series of unique political and cultural factors linking Luxembourg and these two (neo)colonial regimes account for the financial activities that developed between the three jurisdictions. As such, I show that officials in the Belgian Congo and Apartheid South Africa were able to count on their Luxembourg-based bankers for a variety of finance-related services, including the provision of Eurocurrency loans and the formation of offshore companies. In doing so, the article contributes to a body of literature in the social sciences of finance that has grown significantly in recent years: on the imperial and neocolonial basis of the contemporary global financial system.

In comparison to other high-risk industrial sectors, human rights due diligence (HRDD) in the arms sector remains unclear and underdeveloped. This article elucidates how supply chain regulations can provide pertinent guidance for clarifying and elaborating the standards and requirements of the HRDD obligations of arms companies. Part I reaffirms the importance of independent HRDD obligations for arms companies due to the significant human rights risks posed by arms exports. Part II contextualises the limitations in the development of HRDD in the arms industry by examining the corporate policies of major arms companies. Part III explicates why supply chain regulations for conflict minerals are suitable guidance for clarifying and elaborating the HRDD obligations of arms companies. Part IV details five elements of an HRDD framework for arms companies that are essential for comprehensively identifying, evaluating and addressing the human rights risks of arms exports. Part V offers concluding remarks.

We perform experiments in the Large Plasma Device at the University of California, Los Angeles, studying how different end-electrode biasing schemes modify the radial potential profile in the machine. We impose biasing profiles of different polarities and gradient signs on a set of five concentric electrodes placed 12 m downstream from the plasma source. We find that imposing concave-down profiles (negative potential radial gradient) on the electrodes creates radial potential profiles halfway up the plasma column that are comparable to those imposed on the electrodes and a few electron temperature in height, regardless of the biasing polarity. On the other hand, imposing concave-up profiles (positive potential radial gradient) leads to non-monotonic radial potential profiles. This observation can be explained by the current drawn through the electrodes and the parallel plasma resistivity, highlighting their important role in controlling the rotation of plasma. Concave-down plasma potential profiles, obtained by drawing electrons on the axis, are predicted to drive azimuthal drift velocities that can approach significant fractions of the ion sound speed in the central region of the plasma column.

What has actually happened to the political economy of the United States over the last half-century? For too long now, ‘neoliberalism’ has been the standard answer given, yet today, the term seems to have lost both its analytic and critical capacities. Melinda Cooper’s Counterrevolution offers readers a fresh and productive response to this fundamental question of contemporary political economy. Cooper comes neither to praise nor bury neoliberalism but to shift from the level of generalizing accounts or polemics to the level of concrete ideas and the policies they have engendered. She directs attention away from the Chicago school and toward both the Virginia School of public choice theory and a long line of supply-side thinkers. On strictly economic grounds, these two strands ought to be in tension, but Cooper illuminates their political convergence: agreeing to constrain ‘certain kinds of public spending’, they implemented a politics committed to inflating asset values for the wealthy while holding workers’ wage growth in check. This balance-sheet insurrection, which directs the flow of capitalist value upward, stopped and reversed the potential Keynesian revolution that had been underway in the 1950s and 1960s.

For any prime p and S a p-group isomorphic to a Sylow p-subgroup of a rank $2$ simple group of Lie type in characteristic p, we determine all saturated fusion systems supported on S up to isomorphism.

Friendship with the ancients is a set of imaginative exercises and engagements with the work of deceased authors that allows us to imagine them as friends. Authors from diverse cultures and times such as Mengzi, Niccolò Machiavelli, W.E.B. Du Bois, and Clare Carlisle have engaged in it. The aim of this article is to defend this practice, showing that friendship with the ancients is a species of philosophical friendship, which confers the unique benefits such friendships offer. It is conducive to epistemic virtue, notably the related virtues of epistemic humility and of relational understanding. When we cultivate friendship with the ancients, we are not learning facts about them, but aim at understanding their views in their full scope in a way that a relationship between friends allows.

Simulating plasma physics on quantum computers is difficult because most problems of interest are nonlinear, but quantum computers are not naturally suitable for nonlinear operations. In weakly nonlinear regimes, plasma problems can be modelled as wave–wave interactions. In this paper, we develop a quantization approach to convert nonlinear wave–wave interaction problems to Hamiltonian simulation problems. We demonstrate our approach using two qubits on a superconducting device. Unlike a photonic device, a superconducting device does not naturally have the desired interactions in its native Hamiltonian. Nevertheless, Hamiltonian simulations can still be performed by decomposing required unitary operations into native gates. To improve experimental results, we employ a range of error-mitigation techniques. Apart from readout error mitigation, we use randomized compilation to transform undiagnosed coherent errors into well-behaved stochastic Pauli channels. Moreover, to compensate for stochastic noise, we rescale exponentially decaying probability amplitudes using rates measured from cycle benchmarking. We carefully consider how different choices of product-formula algorithms affect the overall error and show how a trade-off can be made to best utilize limited quantum resources. This study provides an example of how plasma problems may be solved on near-term quantum computing platforms.

Motivated by the impact of emerging technologies on (toll) parks, this paper studies a problem of customers’ strategic behavior, social optimization, and revenue maximization for infinite-server queues. More specifically, we assume that a customer’s utility consists of a positive reward for receiving service minus a cost caused by the other customers in the system. In the observable setting, we show the existence, uniqueness, and expressions of the individual equilibrium threshold, the socially optimal threshold, and the optimal revenue threshold, respectively. Then, we prove that the optimal revenue threshold is smaller than the socially optimal threshold, which is smaller than the individual one. Furthermore, we also extend the cost functions to any finite polynomial function with nonnegative coefficients. In the unobservable setting, we derive the joining probabilities of individual equilibrium and optimal revenue. Finally, using numerical experiments, we complement our results and compare the social welfare and the revenue under these two information levels.

Psychiatric comorbidity is common in children and adolescents with CHDs. Early recognition and evidence-based treatments are crucial to prevent long-term consequences. To support early identification and reduce stigma, we 1) developed and 2) tested the usability and acceptability of online information material on common mental health disorders targeted healthcare professionals and affected families. Website content was shaped by insights from interviews with healthcare professionals across sectors, parents, and adolescents. Evaluations demonstrated promising acceptability and usability of the first prototype but indicated the need for improvements in specific aspects of content, navigation, and overall aesthetics.

Hedonic models that seek to explain the observable variation in wine and beer prices have so far included alcohol by volume (ABV) only as a control variable without paying much attention to the magnitude of the coefficient and without questioning the implicit assumption that the impact of ABV on bottle prices is indeed linear. Using data from the “Austrian Spirits Trophy 2023,” we find the relationship between ABV and bottle prices to be nonlinear, with statistically significant effects observed for linear, squared, and cubic terms of alcohol content. Moreover, we find expert evaluations of spirits to demonstrate a nonlinear relationship with ABV too.

Le fardeau administratif renvoie au phénomène selon lequel la mise en œuvre des politiques publiques et, plus généralement, les interactions avec l’État, sont coûteuses et difficiles. Chaque personne est en effet confrontée à des coûts d'apprentissage lorsqu'elle acquiert de l'information sur les programmes et services publics, à des coûts de conformité lorsqu'elle tente de satisfaire à leurs règles, et à des coûts psychologiques (stress, etc.) lorsqu'elle interagit avec ceux-ci. Cette littérature, presque exclusivement anglophone, s'est développée à un rythme effréné. Cette synthèse critique fait le bilan de ces récents développements et propose une discussion articulée autour de trois thèmes : 1) Que sont les fardeaux administratifs et quels enjeux soulèvent-ils? ; 2) Quelles sont les sources des fardeaux? ; et 3) Quelles en sont les conséquences distributives et politiques? Des pistes de recherche future sont proposées pour chacun de ces thèmes.

Simultaneous ultra-intense pulses at petawatt laser facilities enable a broad range of experiments in nuclear photonics and strong field quantum electrodynamics. These experiments often require very precise control of the time delays between pulses. We report measurements of the time delay between the two 1 PW outputs of the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility in Romania. The short-term standard deviation of the time delay was approximately half of the pulse duration of 23 fs, and the average delay drifted with up to 100 fs/h. The drift and sporadic delay jumps were corrected using a feedback loop, which reduced the long-term standard deviation of the delay close to its short-term value. These results imply that in ELI-NP experiments using two simultaneous pulses, a temporal overlap of better than half of the pulse duration can be achieved for more than two thirds of the shots, which would enable high data rate experiments using simultaneous petawatt pulses.

Weeds are one of the greatest challenges to snap bean (Phaseolus vulgaris L.) production. Anecdotal observation posits certain species frequently escape the weed management system by the time of crop harvest, hereafter called residual weeds. The objectives of this work were to (1) quantify the residual weed community in snap bean grown for processing across the major growing regions in the United States and (2) investigate linkages between the density of residual weeds and their contributions to weed canopy cover. In surveys of 358 fields across the Northwest (NW), Midwest (MW), and Northeast (NE), residual weeds were observed in 95% of the fields. While a total of 109 species or species-groups were identified, one to three species dominated the residual weed community of individual fields in most cases. It was not uncommon to have >10 weeds m−2 with a weed canopy covering >5% of the field’s surface area. Some of the most abundant and problematic species or species-groups escaping control included amaranth species such as smooth pigweed (Amaranthus hybridus L.), Palmer amaranth (Amaranthus palmeri S. Watson), redroot pigweed (Amaranthus retroflexus L.), and waterhemp [Amaranthus tuberculatus (Moq.) Sauer]; common lambsquarters (Chenopodium album L.); large crabgrass [Digitaria sanguinalis (L.) Scop.]; and ivyleaf morningglory (Ipomoea hederacea Jacq.). Emerging threats include hophornbeam copperleaf (Acalypha ostryifolia Riddell) in the MW and sharppoint fluvellin [Kickxia elatine (L.) Dumort.] in the NW. Beyond crop losses due to weed interference, the weed canopy at harvest poses a risk to contaminating snap bean products with foreign material. Random forest modeling predicts the residual weed canopy is dominated by C. album, D. sanguinalis, carpetweed (Mollugo verticillata L.), I. hederacea, amaranth species, and A. ostryifolia. This is the first quantitative report on the weed community escaping control in U.S. snap bean production.

Traditionally, corruption is seen as a rational pursuit of profit, focusing on personal gain. However, this view overlooks other influences. This paper focuses on the behavioral aspects of corruption, providing a deeper understanding of its complexities, and addressing the factors overlooked by conventional approaches. Reviewing some of the literature, we highlight how researchers have approached corruption from the perspective of behavioral sciences. Additionally, we examine how the emerging discipline of Behavioral Public Policy (BPP) employs innovative methods to reduce corrupt practices, offering new strategies that transcend traditional perspectives. Our paper innovates by demonstrating how corruption can be reduced by substituting traditional regulations with nonregulatory tools like nudges and sludge audits, or by leveraging digital choice architectures to minimize human-to-human interactions, known corruption enablers. By reducing regulations and administrative red tape, and introducing digital frameworks, these tools simplify processes minimizing opportunities for corrupt behavior. In this paper, we aim to infuse corruption research with a behavioral twist, a digital approach, and a deregulatory perspective, offering policymakers an alternative path to foster transparency, accountability and ethical governance. While this approach will not completely eradicate corruption, it strives to show how BPP can reduce its occurrences.

Protocols for Postcapitalist Expression is a book published by members of the Economic Space Agency. Its objective is to frame protocols (social agreements) on which to build the conditions for an economic system that is distributed (no centralised control) and can express network views about what constitutes, and how to measure, ‘value’ (value beyond profit). An insightful review by William Morgan (2024) probes some key dimensions of our project. This reply both reframes some of William’s insights and takes issue with others, especially those which emphasise a Hayekian interpretation.