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We present simultaneous X-ray and spectral ultraviolet (UV) observations of strikingly-coherent oscillations in emission from a coronal looptop and fan structure, during the impulsive phase of a long-duration M-class solar flare. The 50 s oscillations are observed near in-phase by Solar Orbiter/STIX, GOES, and IRIS Fe XXI intensity, Doppler and non-thermal velocity. For over 5 minutes of their approximate 35 minute duration, the oscillations are so periodic (2-sigma above the power law background), that they are better described as 'periodic pulsations' than the more-widely documented 'quasi-periodic pulsations' often observed during solar flares. By combining time-series analysis of the the multi-instrument datasets with comparison to MHD simulations, we attribute the oscillations to the magnetic tuning fork in the flare looptop-fan region, and betatron acceleration within the lower-altitude flare loops. These interpretations are possible due to the introduced 'Sliding Raster Method' (SliRM) for analysis of slit spectrometer (e.g. IRIS) raster data, to increase the temporal cadence of the observations at the expense of spatial information., Comment: 16 pages, 7 figures, (+1 page, 2 figure appendix); accepted for publication to ApJ

OT 081 is a well-known, luminous blazar that is remarkably variable in many energy bands. We present the first broadband study of the source which includes very-high-energy (VHE, $E>$100\,GeV) $\gamma$-ray data taken by the MAGIC and H.E.S.S. imaging Cherenkov telescopes. The discovery of VHE $\gamma$-ray emission happened during a high state of $\gamma$-ray activity in July 2016, observed by many instruments from radio to VHE $\gamma$-rays. We identify four states of activity of the source, one of which includes VHE $\gamma$-ray emission. Variability in the VHE domain is found on daily timescales. The intrinsic VHE spectrum can be described by a power-law with index $3.27\pm0.44_{\rm stat}\pm0.15_{\rm sys}$ (MAGIC) and $3.39\pm0.58_{\rm stat}\pm0.64_{\rm sys}$ (H.E.S.S.) in the energy range of 55--300\,GeV and 120--500\,GeV, respectively. The broadband emission cannot be sucessfully reproduced by a simple one-zone synchrotron self-Compton model. Instead, an additional external Compton component is required. We test a lepto-hadronic model that reproduces the dataset well and a proton-synchrotron dominated model that requires an extreme proton luminosity. Emission models that are able to successfully represent the data place the emitting region well outside of the Broad Line Region (BLR) to a location at which the radiative environment is dominated by the infrared thermal radiation field of the dusty torus. In the scenario described by this flaring activity, the source appears to be an FSRQ, in contrast with past categorizations. This suggests that the source can be considered to be a transitional blazar, intermediate between BL~Lac and FSRQ objects., Comment: Accepted on MNRAS Corresponding authors: M. Manganaro, J. Becerra Gonz\'alez, M. Seglar-Arroyo, D. A. Sanchez

Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain the multi-wavelength behaviour of BL Lacertae, the prototype of one of the blazar classes. According to this model, the jet is inhomogeneous, curved, and twisting, and the long-term variability is due to changes in the Doppler factor due to variations in the orientation of the jet-emitting regions. We analysed optical data of the source obtained during monitoring campaigns organised by the Whole Earth Blazar Telescope (WEBT) in 2019-2022, together with radio data from the WEBT and other teams, and gamma-ray data from the Fermi satellite. In this period, BL Lacertae underwent an extraordinary activity phase, reaching its historical optical and gamma-ray brightness maxima. The application of the twisting jet model to the source light curves allows us to infer the wiggling motion of the optical, radio, and gamma-ray jet-emitting regions. The optical-radio correlation shows that the changes in the radio viewing angle follow those in the optical viewing angle by about 120 days, and it suggests that the jet is composed of plasma filaments, which is in agreement with some radio high-resolution observations of other sources. The gamma-ray emitting region is found to be co-spatial with the optical one, and the analysis of the gamma-optical correlation is consistent with both the geometric interpretation and a synchrotron self-Compton (SSC) origin of the high-energy photons. We propose a geometric scenario where the jet is made up of a pair of emitting plasma filaments in a sort of double-helix curved rotating structure, whose wiggling motion produces changes in the Doppler beaming and can thus explain the observed multi-wavelength long-term variability., Comment: In press for A&A

Many modern radio telescopes employ an observational strategy that involves maximizing the use of their available spaces (cabins), outfitting them with various receivers at different frequencies to detect incoming signals from the sky simultaneously or individually. The Large Latin American Millimeter Array (LLAMA), is a joint venture between Argentina and Brazil consisting of the installation and operation of a 12-meter aperture Cassegrain telescope. It features three available cabins for instrumentation and plans to install six single-pixel heterodyne receivers, covering different bandwidths in the 30 to 950 GHz window of the electromagnetic spectrum, in its two lateral Nasmyth cabins at different phases of the project. Therefore, it is crucial not only to design a tertiary optical system that couples the antenna beam to those receivers, but also to do it in a scalable way. The primary goal for the design is to simultaneously maximize the antenna efficiency while minimizing optical aberrations for all receivers, both fundamental aspects for the optimal functioning of cutting-edge astronomical instruments. In this paper, we present the entire design process, starting from the quasi-optical approach based on the propagation of a fundamental Gaussian beam mode, continuing with the validation of the design based on physical optics simulations, and ending with a tolerance analysis of the system. As a result of this process, a frequency independent tertiary optical system has been achieved for almost all the receivers, which is expected to provide high optical performance for the radio telescope., Comment: 44pages, 28 figures, 14 tables

We show that the category of ind-coherent sheaves on a quasi-smooth scheme is naturally tensored over the category of sheared D-modules on its shifted cotangent bundle, commuting with its natural action of categorified Hoschschild cochains. We prove that it defines a Morita equivalence as such. We then extend these results to quasi-smooth Artin stacks. As a consequence of our formalism, we are able to articulate a precise sense in which the space of unramified automorphic functions over a function field localizes over the stack of arithmetic Arthur parameters., Comment: 69 p

Chronic wounds and associated complications present ever growing burdens for clinics and hospitals world wide. Venous, arterial, diabetic, and pressure wounds are becoming increasingly common globally. These conditions can result in highly debilitating repercussions for those affected, with limb amputations and increased mortality risk resulting from infection becoming more common. New methods to assist clinicians in chronic wound care are therefore vital to maintain high quality care standards. This paper presents an improved HarDNet segmentation architecture which integrates a contrast-eliminating component in the initial layers of the network to enhance feature learning. We also utilise a multi-colour space tensor merging process and adjust the harmonic shape of the convolution blocks to facilitate these additional features. We train our proposed model using wound images from light-skinned patients and test the model on two test sets (one set with ground truth, and one without) comprising only darker-skinned cases. Subjective ratings are obtained from clinical wound experts with intraclass correlation coefficient used to determine inter-rater reliability. For the dark-skin tone test set with ground truth, we demonstrate improvements in terms of Dice similarity coefficient (+0.1221) and intersection over union (+0.1274). Qualitative analysis showed high expert ratings, with improvements of >3% demonstrated when comparing the baseline model with the proposed model. This paper presents the first study to focus on darker-skin tones for chronic wound segmentation using models trained only on wound images exhibiting lighter skin. Diabetes is highly prevalent in countries where patients have darker skin tones, highlighting the need for a greater focus on such cases. Additionally, we conduct the largest qualitative study to date for chronic wound segmentation.

We investigate the star formation-AGN connection in the Seyfert 1 NGC 7469 using James Webb Space Telescope (JWST) mid-infrared spectroscopic integral field unit (IFU) data. We use the IFU data to generate maps of different emission lines present in the spectrum, such as the star-formation (SF) tracer [Ne II] 12.81{\mu}m, or the AGN tracer [Ne V] 14.32{\mu}m. We can separate the AGN- and SF-dominated regions using spatially resolved mid-IR diagnostic diagrams, and further investigate the ionization sources powering each region by constructing photoionization models. We find that the previously detected eastern wind populates an intermediary region of the diagrams, between our star-forming and AGN quadrants. Although it is possible that the star forming ring may inherently not be uniform, this wind also coincides with a reduction in the [Ne II] emission in the ring, which suggests that the ionization cone intersects the ring in this direction., Comment: 13 pages, 5 figures, submitted to ApJ

This report analyzes the potential for large language models (LLMs) to expedite accurate replication of published message effects studies. We tested LLM-powered participants (personas) by replicating 133 experimental findings from 14 papers containing 45 recent studies in the Journal of Marketing (January 2023-May 2024). We used a new software tool, Viewpoints AI (https://viewpoints.ai/), that takes study designs, stimuli, and measures as input, automatically generates prompts for LLMs to act as a specified sample of unique personas, and collects their responses to produce a final output in the form of a complete dataset and statistical analysis. The underlying LLM used was Anthropic's Claude Sonnet 3.5. We generated 19,447 AI personas to replicate these studies with the exact same sample attributes, study designs, stimuli, and measures reported in the original human research. Our LLM replications successfully reproduced 76% of the original main effects (84 out of 111), demonstrating strong potential for AI-assisted replication of studies in which people respond to media stimuli. When including interaction effects, the overall replication rate was 68% (90 out of 133). The use of LLMs to replicate and accelerate marketing research on media effects is discussed with respect to the replication crisis in social science, potential solutions to generalizability problems in sampling subjects and experimental conditions, and the ability to rapidly test consumer responses to various media stimuli. We also address the limitations of this approach, particularly in replicating complex interaction effects in media response studies, and suggest areas for future research and improvement in AI-assisted experimental replication of media effects., Comment: 24 pages, 3 figures, 2 tables

PG 1448+273 is a luminous, nearby ($z=0.0645$), narrow line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. Previous X-ray observations of PG 1448 with XMM-Newton in 2017 and NuSTAR in 2022 revealed the presence of an ultra fast outflow, as seen through its blueshifted iron K absorption profile, where the outflow velocity appeared to vary in the range $0.1-0.3c$. In this work, new X-ray observations of PG 1448 are presented, in the form of four simultaneous XMM-Newton and NuSTAR observations performed in July and August 2023. The X-ray spectra appeared at a similar flux in each observation, making it possible to analyze the mean 2023 X-ray spectrum at high signal to noise. A broad ($\sigma=1$ keV) and highly blue-shifted ($E=9.8\pm0.4$ keV) iron K absorption profile is revealed in the mean spectrum. The profile can be modeled by a fast, geometrically thick accretion disk wind, which reveals a maximum terminal velocity of $v_{\infty}=-0.43\pm0.03c$, one of the fastest known winds in a nearby AGN. As a result, the inferred mass outflow rate of the wind may reach a significant fraction of the Eddington accretion rate., Comment: 15 pages, accepted for publication in the Astrophysical Journal

This paper addresses, for the first time, a key aspect of the phenomenology of Compact Symmetric Objects (CSOs) -- the characteristics of their radio spectra. We present a radio-spectrum description of a complete sample of high luminosity CSOs (CSO-2s), which shows that they exhibit the \textit{complete} range of spectral types, including flat-spectrum sources ($\alpha \ge -0.5$), steep-spectrum sources ($\alpha < -0.5$), and peaked-spectrum sources. We show that there is no clear correlation between spectral type and size, but there is a correlation between the high-frequency spectral index and both object type and size. We also show that, to avoid biasing the data and to understand the various classes of jetted-AGN involved, the complete range of spectral types should be included in studying the general phenomenology of compact jetted-AGN, and that complete samples must be used, selected over a wide range of frequencies. We discuss examples that demonstrate these points. We find that the high-frequency spectral indices of CSO-2s span $-1.3 <\alpha_{\rm hi} < -0.3$, and hence that radio spectral signatures cannot be used to discriminate definitively between CSO-2s, binary galactic nuclei, and millilensed objects, unless they have $\alpha_{\rm hi} >-0.3$.

Owens Valley Radio Observatory (OVRO) observations of supermassive black hole binary (SMBHB) candidate PKS~2131$-$021 revealed, for the first time, six likely characteristics of the phenomenology exhibited by SMBHB in blazars, of which the most unexpected and critical is sinusoidal flux density variations. We have now identified a second blazar, PKS~J0805$-$0111, showing significant sinusoidal variations, with an observed period that translates to $1.422 \pm 0.005$ yr in the rest frame of the $z = 1.388$ object. We generate $10^6$ simulated light curves to reproduce the radio variability characteristics of PKS~J0805$-$0111, and show that the global probability, considering the \textit{look-elsewhere effect}, indicates that the observed periodicity can be attributed to the red noise tail of the power spectral density, with a $p_0$ value of $7.8 \times 10^{-5}$ (i.e. 3.78$\sigma$). PKS J0805$-$0111 displays all six characteristics observed in PKS 2131$-$021. Taking into account the well-defined OVRO sample size, the false positive probability $\sim 0.22$, but the rare behavior makes this a strong SMBHB candidate. The discovery of a second SMBHB candidate exhibiting these rare characteristics reveals that PKS~2131$-$021 is not a unique, isolated case. With these two strong cases we are clearly seeing only the tip of the iceberg. We estimate that the number of SMBHB candidates amongst blazars $\sim$ 1 in 100.

We study the creation and breakdown of a quantized vortex shear layer forming between a stationary Bose-Einstein condensate and a stirred-in persistent current. Once turbulence is established, we characterize the progressive clustering of the vortices, showing that the cluster number follows a power law decay with time, similar to decaying turbulence in other two-dimensional systems. Numerical study of the system demonstrates good agreement of the experimental data with a point vortex model that includes damping and noise. With increasing vortex number in the computational model, we observe a convergence of the power-law exponent to a fixed value., Comment: 8 pages, 8 figures

The ability to form diamond electrodes on insulating polycrystalline diamond substrates using single-step laser patterning, and the use of the electrodes as a substrate that supports the adhesion and proliferation of human mesenchymal stem cells (hMSCs) is demonstrated. Laser induced graphitisation results in a conductive amorphous carbon surface, rich in oxygen and nitrogen terminations. This results in an electrode with a high specific capacitance of 182 uF/cm2, a wide water window of 3.25 V, and a low electrochemical impedance of 129 Ohms/cm2 at 1 kHz. The electrodes surface exhibited a good level of biocompatibility with hMSCs, supporting cell adhesion and proliferation. The cells cultured on the electrode displayed significant elongation and alignment along the direction of the laser patterned microgrooves. Because of its favourable electrochemical performance and biocompatibility, the laser-patterned diamond electrodes create a potential for a versatile platform in stem cell therapeutics.

In the business rules of supply chains, there are concerns around trust, truth, demonstrability and authenticity. These concerns are gathered together under the name ``veracity". In the work for this paper we were originally motivated by the requirement around organic certification in the wine industry in New Zealand, but veracity arises in many different situations and our formalisation shows how formal methods can give insights into many such practical problems. One activity for formal methods involves taking informal processes and formalising them and subsequently building tools to support this formalisation and therefore the original processes too, and the work reported here is an example of that. Here, then, we explore the idea of veracity in this spirit, give highlights of the development of a logic for it and show how that logic can be implemented in Coq, both for proof support and automation., Comment: arXiv admin note: substantial text overlap with arXiv:2302.06164

Understanding the dynamics of nonequilibrium quantum many-body systems is an important research topic in a wide range of fields across condensed matter physics, quantum optics, and high-energy physics. However, numerical studies of large-scale nonequilibrium phenomena in realistic materials face serious challenges due to intrinsic high-dimensionality of quantum many-body problems. The nonequilibrium properties of many-body systems can be described by the dynamics of the Green's function of the system, whose time evolution is given by a high-dimensional system of integro-differential equations, known as the Kadanoff-Baym equations (KBEs). The time-convolution term in KBEs, which needs to be recalculated at each time step, makes it difficult to perform long-time simulations. In this paper, we develop an operator-learning framework based on Recurrent Neural Networks (RNNs) to address this challenge. The proposed framework utilizes RNNs to learn the nonlinear mapping between Green's functions and convolution integrals in KBEs. By using the learned operators as a surrogate model in the KBE solver, we obtain a general machine-learning scheme for predicting the dynamics of nonequilibrium Green's functions. This new methodology reduces the temporal computational complexity from $O(N_t^3)$ to $O(N_t)$, where $N_t$ is the total time steps taken in a simulation, thereby making it possible to study large many-body problems which are currently infeasible with conventional KBE solvers. Through different numerical examples, we demonstrate the effectiveness of the operator-learning based approach in providing accurate predictions of physical observables such as the reduced density matrix and time-resolved photoemission spectra. Moreover, our framework exhibits clear numerical convergence and can be easily parallelized, thereby facilitating many possible further developments and applications.

Haystack and Owens Valley Radio Observatory (OVRO) observations recently revealed strong sinusoidal total flux density variations that maintained coherence between 1975 and 2021 in the blazar PKS 2131-021 ($z=1.283)$. This was interpreted as possible evidence of a supermassive black hole binary (SMBHB). Extended observations through 2023 show coherence over 47.9~years, with an observed period $P_\textrm{15 GHz}=(1739.3 \pm 1.2) \, {\rm days}$. We reject, with $p$-value = $5.3 \times 10^{-7}$, the hypothesis that the variations are due to random fluctuations in the red noise tail of the power spectral density. There is clearly a constant-period physical phenomenon in PKS 2131-021 producing coherent intermittent sinusoidal flux density variations. We find the coherent sinusoidal intensity variations extend from below 2.7 GHz to optical frequencies, from which we derive an observed period $P_\textrm{optical}=(1764 \pm 36)$ days. Across this broad frequency range there is a monotonic phase shift in the sinusoidal variations with frequency. The same coherent periodicity is possibly also observed at $\gamma$-ray energies. The importance of well-vetted SMBHB candidates to searches for gravitational waves is pointed out. We estimate the fraction of blazars that are SMBHB candidates to be $>1$ in 100. Thus monitoring programs covering tens of thousands of blazars could discover hundreds of SMBHB candidates., Comment: 23 pages, 17 figures, 5 tables, submitted to ApJ

Generative AI (GenAI) and large language models in particular, are disrupting Computer Science Education. They are proving increasingly capable at more and more challenges. Some educators argue that they pose a serious threat to computing education, and that we should ban their use in the classroom. While there are serious GenAI issues that remain unsolved, it may be useful in the present moment to step back and examine the overall trajectory of Computer Science writ large. Since the very beginning, our discipline has sought to increase the level of abstraction in each new representation. We have progressed from hardware dip switches, through special purpose languages and visual representations like flow charts, all the way now to ``natural language.'' With the advent of GenAI, students can finally change the abstraction level of a problem to the ``language'' they've been ``problem solving'' with all their lives. In this paper, we argue that our programming abstractions were always headed here -- to natural language. Now is the time to adopt a ``Prompts First'' approach to Computer Science Education., Comment: 4 pages

The origin of high-energy (HE) astrophysical neutrinos has remained an elusive hot topic in the field of HE astrophysics for the past decade. Apart from a handful of individual associations, the vast majority of HE neutrinos arise from unknown sources. While there are theoretically-motivated candidate populations, such as blazars -- a subclass of AGN with jets pointed towards our line-of-sight -- they have not yet been convincingly linked to HE neutrino production. Here, we perform a spatio-temporal association analysis between a sample of blazars (from CGRaBS catalog) in the radio and optical bands and the most up-to-date IceCube HE neutrino catalog. We find that if the IceCube error regions are enlarged by 1$^\circ$ in quadrature, to account for unknown systematic errors at maximal level, a spatio-temporal correlation between the multiwavelength light curves of the CGRaBS blazars and the IceCube HE neutrinos is hinted at least at a 2.17$\sigma$ significance level. On the other hand, when the IceCube error regions are taken as their published values, we do not find any significant correlations. A discrepancy in the blazar-neutrino correlation strengths, when using such minimal and enlarged error region scenarios, was also obtained in a recent study by the IceCube collaboration. In our study, this difference arises because several flaring blazars -- coinciding with a neutrino arrival time -- happen to narrowly miss the published 90\%-likelihood error region of the nearest neutrino event. For all of the associations driving our most significant correlations, the flaring blazar is much less than 1$^\circ$ away from the published error regions. Therefore, our results indicate that the question of the blazar-neutrino connection is highly sensitive to the reconstruction of the neutrino error regions, whose reliability is expected to improve with the next generation of neutrino observatories., Comment: Accepted for publication in A&A, 24 pages, 10 figures, 2 tables, 3 electronic tables

The digital footprints of today's internet-active individuals are a testament to their lives, and have the potential to become digital legacies once they pass on. Future descendants of those alive today will greatly appreciate the unprecedented insight into the lives of their long since deceased ancestors, but this can only occur if today we have a process for data preservation and handover after death. Many prominent online platforms offer nebulous or altogether absent policies regarding posthumous data handling, and despite recent advances it is currently unclear who the average Australian would like their data to be managed after their death (i.e., social media platforms, a trusted individual, or another digital executor). While at present the management of deceased accounts is largely performed by the platform (e.g., Facebook), it is conceivable that many Australians may not trust such platforms to do so with integrity. This study aims to further the academic conversation around posthumous data by delving deeper into the preferences of the Australian Public regarding the management of their data after death, ultimately to inform future development of research programs and industry solutions. A survey of 1020 Australians revealed that most desired a level of control over how their data is managed after death. Australians currently prefer to entrust the management of their data to a trusted close individual or third party software that they can administrate themselves. As expected, social media companies ranked low regarding both trust and convenience to manage data after death. Future research focus should be to conceptualise and develop a third-party solution that enables these preferences to be realised. Such a solution could interface with the major online vendors (social media, cloud hosting etc.) to action the deceased's will., Comment: Accepted at 18th International Symposium on Human Aspects of Information Security and Assurance

The current sheet is an essential feature in solar flares and is the primary site for magnetic reconnetion and energy release. Imaging observations feature a long linear structure above the candle-flame-shaped flare loops, which resembles the standard flare model with the current sheet viewed edge-on. We investigate the thermal properties of plasmas surrounding the linear sheet during flares, using EUV observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The differential emission measure (DEM) analyses show evidence of high temperatures in the plasma sheets (PSs), containing hot emissions from only a narrow temperature range, suggestive of an isothermal feature. The sheet's temperature remains constant at different heights above the flare arcade, peaking at around logT=7.0-7.1; while the well-studied 2017 September 10 X8.2 flare exhibits as an exception in that the temperature decreases with an increasing height and peaks higher (logT=7.25) during the gradual phase. Most PS cases also hold similar emission measures and thicknesses; while the PS's emissions drop exponentially above the flare arcade, the sheet thicknesses show no significant height association as for all the measurements. The characteristics of isothermal and steady temperature suggests balanced heating and cooling processes along the current sheet, particularly additional heating may exist to compensate for the conductive and radiative cooling away from the reconenction site. Our results suggest a steady and uniform sheet structure in the macroscopic scale that results from flare reconnection.

Despite the fundamentally different dissipation mechanisms, many laws and phenomena of classical turbulence equivalently manifest in quantum turbulence. The Reynolds law of dynamical similarity states that two objects of same geometry across different length scales are hydrodynamically equivalent under the same Reynolds number, leading to a universal drag coefficient law. In this work we confirm the existence of a universal drag law in a superfluid wake, facilitated by the nucleation of quantized vortices. We numerically study superfluid flow across a range of Reynolds numbers for the paradigmatic classical hard-wall and the Gaussian obstacle, popular in experimental quantum hydrodynamics. In addition, we provide a feasible method for measuring superfluid drag forces in an experimental environment using control volumes., Comment: 6+2 pages, 3+2 figures, 1 table

[Abridged] ESO 141-G55 is a nearby X-ray bright BLS1, which has been classified as a bare AGN due to the lack of warm absorption along its line-of-sight, providing an unhampered view into its disc-corona system. We aim to probe its disc-corona system thanks to the first simultaneous XMM-Newton and NuSTAR observation obtained on October 1-2, 2022. We carry out the X-ray broadband spectral analysis to determine the dominant process(es) at work, as well as the SED analysis to determine the disc-corona properties. The simultaneous broadband X-ray spectrum of ESO 141-G55 is characterised by the presence of a prominent smooth soft X-ray excess, a broad Fe K emission line and a significant Compton hump. The RGS spectra confirmed the lack of intrinsic warm-absorbing gas along our line of sight in the AGN rest frame, confirming that it is still in a bare state. However, soft X-ray emission lines are observed indicating substantial warm gas out of our line of sight. The intermediate inclination of the disc-corona system, ~43{\deg}, may offer us a favourable configuration to observe UFOs from the disc, but none is found in this 2022 observation, contrary to a previous 2007 XMM-Newton one. Relativistic reflection alone on a standard disc is ruled out from the X-ray broadband analysis, while a combination of soft and hard Comptonisation by a warm and hot corona (relagn), plus relativistic reflection (reflkerrd) reproduces its SED quite well. The hot corona temperature is very hot, ~140 keV, much higher than about 80% of the AGNs, whereas the warm corona temperature, ~0.3 keV, is similar to the values found in other sub-Eddington AGNs. ESO 141-G55 is accreting at a moderate Eddington accretion rate (~10--20%). Our analysis points to a significant contribution of an optically-thick warm corona to both the soft X-ray and UV emission in ESO 141-G55., Comment: 16 pages, 14 figures, 3 appendices; accepted for publication in Astronomy & Astrophysics

IRASF11119 is an ultra-luminous IR galaxy with post-merger morphology, hosting a type-1 QSO at z=0.189. Its 2013 Suzaku spectrum shows a prominent Ultra Fast Outflow (UFO) absorption feature (v_out~0.25c). In 2021, we obtained the first XMM-Newton long look of the target, coordinated with a simultaneous NuSTAR observation. The new high-quality data allow us to detect at P>99.8% c.l. multiple absorption features associated with the known UFO. Furthermore, an emission plus absorption feature at 1.1-1.3 keV reveals the presence of a blueshifted P-Cygni profile in the soft band. We associate the hard band features with blends of FeXXV and FeXXVI He$\alpha$-Ly$\alpha$ and He$\beta$-Ly$\beta$ line pairs and infer a large column (N$_H$~$10^{24}$ cm$^{-2}$) of highly ionized (log$\xi$~5) gas outflowing at v_out=0.27c. The 1 keV feature can be associated with a blend of Fe and Ne transitions, produced by a lower column (N$_H$~$10^{21}$ cm$^{-2}$) and ionization (log$\xi$~2.6) gas component outflowing at the same speed. Using a radiative-transfer disk wind model to fit the highly ionized UFO, we derive a large mass outflow rate, comparable with the mass accretion rate (M$_{out}$=4.25 M$_{Sun}$/yr, ~1.6 M$_{acc}$), and kinetic energy and momentum flux among the highest reported in the literature. We measure an extremely low high-energy cut-off (E$_c$~25 keV). Several other cases in the literature suggest that a steep X-ray continuum may be related to the formation of powerful winds. The lack of a significant momentum boost between the nuclear UFO and the different phases of the large-scale outflow, observed in IRASF11119 and in a growing number of sources with powerful UFOs, can be explained by (i) a momentum-driven expansion, (ii) an inefficient coupling of the UFO with the host ISM, or (iii) by repeated energy-driven expansion episodes with low duty-cycle, that average out on long time-scales., Comment: 21 pages, 13 figures, accepted for publication in A&A

The stable unit treatment value assumption states that the outcome of an individual is not affected by the treatment statuses of others, however in many real world applications, treatments can have an effect on many others beyond the immediately treated. Interference can generically be thought of as mediated through some network structure. In many empirically relevant situations however, complete network data (required to adjust for these spillover effects) are too costly or logistically infeasible to collect. Partially or indirectly observed network data (e.g., subsamples, aggregated relational data (ARD), egocentric sampling, or respondent-driven sampling) reduce the logistical and financial burden of collecting network data, but the statistical properties of treatment effect adjustments from these design strategies are only beginning to be explored. In this paper, we present a framework for the estimation and inference of treatment effect adjustments using partial network data through the lens of structural causal models. We also illustrate procedures to assign treatments using only partial network data, with the goal of either minimizing estimator variance or optimally seeding. We derive single network asymptotic results applicable to a variety of choices for an underlying graph model. We validate our approach using simulated experiments on observed graphs with applications to information diffusion in India and Malawi.

This research explores the use of History to enhance education in the field of ICT For Sustainability ICT4S in response to a challenge from the ICT4S 2023 conference. No previous studies were found in ICT4S but the literature on History and Education for Sustainable Development is reviewed. An ICT4S lecturer collaborated with History lecturers to add an historic parallel to each weeks teaching on a Sustainable Business and Computing unit for final year undergraduate BSc Business Computing students. A list of the topics and rationale is provided. Student perceptions were surveyed before and after the teaching and semi-structured interviews carried out. A majority of students saw relevance to their degree and career. There was an increase in the proportion of students with interest in History. The paper explores the lessons learned from the interdisciplinary collaboration, including topic choice, format and perceived value. The project has enhanced the way we approach our subjects as computing and history educators. We believe this is the first empirical, survey-based study of the use of history to enhance ICT4S education. The team will extend the research to a larger unit covering a wider range of computing degrees.

Novice programmers often struggle through programming problem solving due to a lack of metacognitive awareness and strategies. Previous research has shown that novices can encounter multiple metacognitive difficulties while programming. Novices are typically unaware of how these difficulties are hindering their progress. Meanwhile, many novices are now programming with generative AI (GenAI), which can provide complete solutions to most introductory programming problems, code suggestions, hints for next steps when stuck, and explain cryptic error messages. Its impact on novice metacognition has only started to be explored. Here we replicate a previous study that examined novice programming problem solving behavior and extend it by incorporating GenAI tools. Through 21 lab sessions consisting of participant observation, interview, and eye tracking, we explore how novices are coding with GenAI tools. Although 20 of 21 students completed the assigned programming problem, our findings show an unfortunate divide in the use of GenAI tools between students who accelerated and students who struggled. Students who accelerated were able to use GenAI to create code they already intended to make and were able to ignore unhelpful or incorrect inline code suggestions. But for students who struggled, our findings indicate that previously known metacognitive difficulties persist, and that GenAI unfortunately can compound them and even introduce new metacognitive difficulties. Furthermore, struggling students often expressed cognitive dissonance about their problem solving ability, thought they performed better than they did, and finished with an illusion of competence. Based on our observations from both groups, we propose ways to scaffold the novice GenAI experience and make suggestions for future work., Comment: Accepted to ICER 2024

Wikipedia is one of the most popular websites in the world, serving as a major source of information and learning resource for millions of users worldwide. While motivations for its usage vary, prior research suggests shallow information gathering -- looking up facts and information or answering questions -- dominates over more in-depth usage. On the 22nd of November 2022, ChatGPT was released to the public and has quickly become a popular source of information, serving as an effective question-answering and knowledge gathering resource. Early indications have suggested that it may be drawing users away from traditional question answering services such as Stack Overflow, raising the question of how it may have impacted Wikipedia. In this paper, we explore Wikipedia user metrics across four areas: page views, unique visitor numbers, edit counts and editor numbers within twelve language instances of Wikipedia. We perform pairwise comparisons of these metrics before and after the release of ChatGPT and implement a panel regression model to observe and quantify longer-term trends. We find no evidence of a fall in engagement across any of the four metrics, instead observing that page views and visitor numbers increased in the period following ChatGPT's launch. However, we observe a lower increase in languages where ChatGPT was available than in languages where it was not, which may suggest ChatGPT's availability limited growth in those languages. Our results contribute to the understanding of how emerging generative AI tools are disrupting the Web ecosystem., Comment: 12 pages, 4 figures, submitted to ACM Collective Intelligence

Theoretical descriptions of non equilibrium dynamics of quantum many-body systems essentially employ either (i) explicit treatments, relying on truncation of the expansion of the many-body wave function, (ii) compressed representations of the many-body wave function, or (iii) evolution of an effective (downfolded) representation through Green's functions. In this work, we select representative cases of each of the methods and address how these complementary approaches capture the dynamics driven by intense field perturbations to non equilibrium states. Under strong driving, the systems are characterized by strong entanglement of the single particle density matrix and natural populations approaching those of a strongly interacting equilibrium system. We generate a representative set of results that are numerically exact and form a basis for critical comparison of the distinct families of methods. We demonstrate that the compressed formulation based on similarity transformed Hamiltonians (coupled cluster approach) is practically exact in weak fields and, hence, weakly or moderately correlated systems. Coupled cluster, however, struggles for strong driving fields, under which the system exhibits strongly correlated behavior, as measured by the von Neumann entropy of the single particle density matrix. The dynamics predicted by Green's functions in the (widely popular) GW approximation are less accurate by improve significantly upon the mean-field results in the strongly driven regime., Comment: 11 pages, 2 figures in main text. 11 page supplemental information with 6 figures

Programs executed on a blockchain - smart contracts - have high financial stakes; their correctness is crucial. We argue, that this correctness needs to be foundational: correctness needs to be based on the operational semantics of their execution environment. In this work we present a foundational system - the DeepSEA system - targeting the Ethereum blockchain as the largest smart contract platform. The DeepSEA system has a small but sufficiently rich programming language amenable for verification, the DeepSEA language, and a verified DeepSEA compiler. Together they enable true end-to-end verification for smart contracts. We demonstrate usability through two case studies: a realistic contract for Decentralized Finance and contract for crowdfunding., Comment: 27 pages, 6 figures

This paper introduces a framework for approximate message passing (AMP) in dynamic settings where the data at each iteration is passed through a linear operator. This framework is motivated in part by applications in large-scale, distributed computing where only a subset of the data is available at each iteration. An autoregressive memory term is used to mitigate information loss across iterations and a specialized algorithm, called projection AMP, is designed for the case where each linear operator is an orthogonal projection. Precise theoretical guarantees are provided for a class of Gaussian matrices and non-separable denoising functions. Specifically, it is shown that the iterates can be well-approximated in the high-dimensional limit by a Gaussian process whose second-order statistics are defined recursively via state evolution. These results are applied to the problem of estimating a rank-one spike corrupted by additive Gaussian noise using partial row updates, and the theory is validated by numerical simulations., Comment: 31 pages, 5 figures

Studying the behavior along the galaxy main sequence is key in furthering our understanding of the possible connection between AGN activity and star formation. We select a sample of 1215 AGN from the catalog of SDSS galaxy properties from the Portsmouth group by detection of the high-ionization [Ne V] 3426 \r{A} emission line. Our sample extends from 10$^{40}$ to 10$^{42.5}$ erg/s in [Ne V] luminosity in a redshift range z = 0.17 to 0.57. We compare the specific star formation rates (sSFRs, SFR scaled by galaxy mass) obtained from the corrected [O II] and H{\alpha} luminosities, and the SED-determined values from Portsmouth. We find that the emission-line-based sSFR values are unreliable for the [Ne V] sample due to the AGN contribution, and proceed with the SED sSFRs for our study of the main sequence. We find evidence for a decrease in sSFR along the main sequence in the [Ne V] sample which is consistent with results from the hard X-ray BAT AGN sample, which extends to lower redshifts than our [Ne V] sample. Although we do not find evidence that the concurrent AGN activity is suppressing star formation, our results are consistent with a lower gas fraction in the host galaxies of the AGN as compared to that of the star forming galaxies. If the evacuation of gas, and therefore suppression of star formation is due to AGN activity, it must have occurred in a previous epoch., Comment: 10 pages, 8 figures, 1 table, accepted for publication in ApJ

Autonomous mobile agents often operate in hazardous environments, necessitating an awareness of safety. These agents can have non-linear, stochastic dynamics that must be considered during planning to guarantee bounded risk. Most state of the art methods require closed-form dynamics to verify plan correctness and safety however modern robotic systems often have dynamics that are learned from data. Thus, there is a need to perform efficient trajectory planning with guarantees on risk for agents without known dynamics models. We propose a "generate-and-test" approach to risk-bounded planning in which a planner generates a candidate trajectory using an approximate linear dynamics model and a validator assesses the risk of the trajectory, computing additional safety constraints for the planner if the candidate does not satisfy the desired risk bound. To acquire the approximate model, we use a variational autoencoder to learn a latent linear dynamics model and encode the planning problem into the latent space to generate the candidate trajectory. The VAE also serves to sample trajectories around the candidate to use in the validator. We demonstrate that our algorithm, LaPlaSS, is able to generate trajectory plans with bounded risk for a real-world agent with learned dynamics and is an order of magnitude more efficient than the state of the art.

Globally, there is an increased need for guidelines to produce high-quality data outputs for analysis. No framework currently exists that provides guidelines for a comprehensive approach to producing analysis ready data (ARD). Through critically reviewing and summarising current literature, this paper proposes such guidelines for the creation of ARD. The guidelines proposed in this paper inform ten steps in the generation of ARD: ethics, project documentation, data governance, data management, data storage, data discovery and collection, data cleaning, quality assurance, metadata, and data dictionary. These steps are illustrated through a substantive case study that aimed to create ARD for a digital spatial platform: the Australian Child and Youth Wellbeing Atlas (ACYWA)., Comment: 49 pages, 3 figures, 3 tables, and 5 appendices

We report the serendipitous multiwavelength discovery of a candidate dual black hole system with a separation of ~100 pc, in the gas-rich luminous infrared galaxy MCG-03-34-64 (z=0.016). Hubble Space Telescope/ACS observations show three distinct optical centroids in the [O III] narrow-band and F814W images. Subsequent analysis of Chandra/ACIS data shows two spatially-resolved peaks of equal intensity in the neutral Fe Ka (6.2-6.6 keV) band, while high-resolution radio continuum observations with the Very Large Array at 8.46 GHz (3.6 cm band) show two spatially-coincident radio peaks. Fast shocks as the ionizing source seem unlikely, given the energies required for production of Fe Ka. If confirmed, the separation of ~100 pc would represent the closest dual AGN reported to date with spatially-resolved, multiwavelength observations.

Time-resolved photoemission spectroscopy is the key technique to probe the real-time non-equilibrium dynamics of electronic states. Theoretical predictions of the time dependent spectral function for realistic systems is however, a challenge. Employing the Kadanoff-Baym equations to find this quantity results in a cubic scaling in the total number of time steps, quickly becoming prohibitive and often fail quantitatively and even qualitatively. In comparison, mean-field methods have more favorable numerical scaling both in the number of time steps and in the complexity associated with the cost of evolving for a single time step, however they miss key spectral properties such as emergent spectral features. Here we present a scheme that allows for the inclusion of dynamical correlations to the spectral function while maintaining the same scaling in the number of time steps as for mean-field approaches, while capturing the emergent physics. Further, the scheme can be efficiently implemented on top of equilibrium real-time many-body perturbation theory schemes and codes. We see excellent agreement with exact results for test systems. Furthermore we exemplify the method on a periodic system and demonstrate clear evidence that our proposed scheme produces complex spectral features including excitonic band replicas, features that are not observed using static mean-field approaches., Comment: 7 pages, 3 figures, 14 page supplemental information with 7 additional figures

PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying physical processes driving its variability, the MAGIC Collaboration initiated a multiyear, multiwavelength monitoring campaign in 2015 involving the OVRO 40-m and Medicina radio telescopes, REM, KVA, and the MAGIC telescopes, Swift and Fermi satellites, and the WEBT network. The analysis presented in this paper uses data until 2017 and focuses on the characterization of the variability. The gamma-ray data show a (hint of a) periodic signal compatible with literature, but the X-ray and VHE gamma-ray data do not show statistical evidence for a periodic signal. In other bands, the data are compatible with the gamma-ray period, but with a relatively high p-value. The complex connection between the low and high-energy emission and the non-monochromatic modulation and changes in flux suggests that a simple one-zone model is unable to explain all the variability. Instead, a model including a periodic component along with multiple emission zones is required., Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society. 19 pages, 9 figures. Corresponding authors: Elisa Prandini, Antonio Stamerra, Talvikki Hovatta