Pericardial edema - fluid accumulation within the pericardium - is a frequently observed malformation in zebrafish embryo-based chemical toxicity screens. We recently discovered that the severity of triphenyl phosphate (TPHP)-induced pericardial edema was dependent on the ionic strength of exposure media. TPHP is an aryl phosphate ester (APE) widely used as a plasticizer and flame retardant. APEs are characterized by having one or more aryl groups bound to a phosphate center, with TPHP containing only unsubstituted aryl groups. Therefore, the objective of this study was to begin investigating whether, similar to TPHP, pericardial edema induced by other structurally related APEs is dependent on the ionic composition of exposure media. We first mined the peer-reviewed literature to identify other APEs that 1) induced pericardial edema in zebrafish embryos within a minimum of three peer-reviewed publications, and 2) demonstrated a statistically significant induction of pericardial edema in at least 70 % of the studies evaluated. Based on this meta-analysis, we identified four other APEs that caused pericardial edema in zebrafish embryos: isopropylated triphenyl phosphate (IPTPP), cresyl diphenyl phosphate (CDP), tricresyl phosphate (TMPP), and 2-ethylhexyl diphenyl phosphate (EDHPHP). Using TPHP as a positive control and pericardial edema as a readout, we developed concentration-response curves for all four APEs based on static exposure from 24 to 72 h post-fertilization (hpf). We then conducted co-exposures with D-Mannitol (an osmotic diuretic) and exposures within reverse osmosis (RO) water determine whether the ionic composition of exposure media mitigated APE-induced pericardial edema at 72 hpf. Using pericardial edema as an endpoint, the approximate EC50s 50 s for TPHP (positive control), IPTPP, CDP, TMPP, and EDHPHP were 6.25, 3.125, 3.125, 25, and 100 mu M, respectively, based on exposure from 24 to 72 hpf. Interestingly, similar to our findings with TPHP, co-exposure with D-Mannitol and exposure within ion-deficient water significantly mitigated IPTPP- CDP-, TMPP-, and EDHPHP-induced pericardial edema in zebrafish embryos, suggesting that chemically-induced pericardial edema may be 1) dependent on the ionic composition of exposure media and 2) driven by a disruption in osmoregulation across the embryonic epidermis. Therefore, similar to other assay parameters, our findings underscore the need to standardize the osmolarity of exposure media in order to minimize the potential for false positive/negative hits in zebrafish embryo-based chemical toxicity screens conducted around the world.

The Panoramic Search for Extraterrestrial Intelligence (PANOSETI) experiment is designed to detect pulsed optical signals on nanosecond timescales. PANOSETI is therefore sensitive to Cherenkov radiation generated by extensive air showers, and can be used for gamma-ray astronomy. Each PANOSETI telescope uses a 0.5 m Fresnel lens to focus light onto a 1024 pixel silicon photomultiplier camera that images a 9.9$^\circ\times$9.9$^\circ$ square field of view. Recent detections of PeV gamma-rays from extended sources in the Galactic Plane motivate constructing an array with effective area and angular resolution surpassing current observatories. The PANOSETI telescopes are much smaller and far more affordable than traditional imaging atmospheric Cherenkov telescopes (IACT), making them ideal instruments to construct such an array. We present the results of coincident observations between two PANOSETI telescopes and the gamma-ray observatory VERITAS, along with simulations characterizing the performance of a PANOSETI IACT array.

The goal of the search for extraterrestrial intelligence (SETI) is to quantify the prevalence of technological life beyond Earth via their ‘technosignatures’. One theorized technosignature is narrowband Doppler drifting radio signals. The principal challenge in conducting SETI in the radio domain is developing a generalized technique to reject human radiofrequency interference. Here we present a comprehensive deep-learning-based technosignature search on 820 stellar targets from the Hipparcos catalogue, totalling over 480 h of on-sky data taken with the Robert C. Byrd Green Bank Telescope as part of the Breakthrough Listen initiative. We implement a novel β-convolutional variational autoencoder to identify technosignature candidates in a semi-unsupervised manner while keeping the false-positive rate manageably low, reducing the number of candidate signals by approximately two orders of magnitude compared with previous analyses on the same dataset. Our work also returned eight promising extraterrestrial intelligence signals of interest not previously identified. Re-observations on these targets have so far not resulted in re-detections of signals with similar morphology. This machine-learning approach presents itself as a leading solution in accelerating SETI and other transient research into the age of data-driven astronomy. A state-of-the-art machine-learning method combs a 480-h-long dataset of 820 nearby stars from the SETI Breakthrough Listen project, reducing the number of interesting signals by two orders of magnitude. Further visual inspection identifies eight promising signals of interest from different stars that warrant further observations.

The Cherenkov Telescope Array Observatory (CTAO), thanks to its unprecedented sensitivity in the very high-energy gamma-ray band for transient phenomena and short-timescale variability, will significantly improve the temporal and spectral characterization of the emission of gamma-ray bursts (GRBs) at the highest energies. The Schwarzschild-Couder Telescope (SCT) is a medium-sized telescope candidate for the CTAO Southern Array endowed with an aplanatic dual-mirror optical system and a compact high-imaging-resolution camera. In this contribution, we aim at quantifying the benefit of adding SCTs to the CTAO-South medium-size array already foreseen in the so-called ‘Alpha’ configuration through a comparative study of the performance of different layouts in GRB observations. We report on the simulation and analysis of GRBs from various medium-size array layouts, adopting burst models based on the detections reported by current instruments at different energies. This study is based on CTA Prod3b simulations with an SCT model dating back to 2016. The results will be updated with a new analysis chain that includes the forthcoming updated SCT model from Prod6 simulations. Furthermore, the event reconstruction used for this analysis is a straightforward extension of the analysis thatwas optimized for telescopes with larger pixels and coarser image resolution. Continuing improvements in the simulation model and analysis approach might present significant future changes.

The astronomy community has witnessed an explosive growth in the use of deep-learning techniques based on neural networks since the mid-2010s. The widespread adoption of these nature-inspired technologies has helped astronomers tackle previously insurmountable problems and provided an unprecedented opportunity for new discoveries. However, one of the primary tools of today's optical astronomy is neither natural nor efficient: their photo-sensing devices. Specifically, the modern CCD camera - like that of the cutting-edge Rubin Observatory - requires an internal clock to regularly expose the sensor to light, consumes a large amount of energy and information bandwidth, and has a limited dynamic range. On the contrary, biological eyes lack an internal clock and a shutter, have much higher pixel density but consume significantly less energy and bandwidth, and can adapt to bright and low light conditions. Inspired by the nature of the eyes, M. Mahowald and C. Mead introduced the revolutionary concept of a silicon retina sensor in 1991. Also known as event-based cameras (EBCs), these types of devices operate in a vastly different way compared to conventional CCD-based imaging sensors. EBCs mimic the operating principles of optic nerves and continuously produce a stream of events, with each event generated only when a pixel detects a change in light intensity. EBCs do not have fixed exposure times, have high dynamic range, require low power for operation, and can capture high-speed phenomena. These properties are important requirements for Cherenkov telescopes as well as other high-speed optical astronomy. This work presents the opportunities and challenges of using EBCs in those cases, and proposes a low-cost approach to experimentally assess the feasibility of this innovative technique.

The search for extraterrestrial intelligence (SETI) is a field that has long been within the domain of traditional signal processing techniques. However, with the advent of powerful generative AI models, such as GPT-3, we are now able to explore new ways of analyzing SETI data and potentially uncover previously hidden signals. In this work, we present a novel approach for using generative AI to analyze SETI data, with focus on data processing and machine learning techniques. Our proposed method uses a combination of deep learning and generative models to analyze radio telescope data, with the goal of identifying potential signals from extraterrestrial civilizations. We also discuss the challenges and limitations of using generative AI in SETI, as well as potential future directions for this research. Our findings suggest that generative AI has the potential to significantly improve the efficiency and effectiveness of the search for extraterrestrial intelligence, and we encourage further exploration of this approach in the SETI community. (Disclosure: For the purpose of demonstration, the abstract and title were generated by ChatGPT and slightly modified by the lead author.

Triphenyl phosphate (TPHP) - a widely used organophosphate-based flame retardant - blocks cardiac looping during zebrafish development in a concentration-dependent manner, a phenotype that is dependent on disruption of embryonic osmoregulation and pericardial edema formation. However, it's currently unclear whether (1) TPHP-induced effects on osmoregulation are driven by direct TPHP-induced injury to the embryonic epidermis and (2) whether TPHP-induced pericardial edema is reversible or irreversible following cessation of exposure. Therefore, the objectives of this study were to determine whether TPHP-induced pericardial edema is reversible and whether TPHP causes injury to the embryonic epidermis by quantifying the number of DAPI-positive epidermal cells and analyzing the morphology of the yolk sac epithelium using scanning electron microscopy. First, we found that exposure to 5 mu M TPHP from 24-72 h post-fertilization (hpf) did not increase prolactin - a hormone that regulates ions and water levels - in embryonic zebrafish, whereas high ionic strength exposure media was associated with elevated levels of prolactin. Second, we found that exposure to 5 mu M TPHP from 24-72 hpf did not decrease DAPI-positive epidermal cells within the embryonic epithelium, and that co-exposure with 2.14 mu M fenretinide - a synthetic retinoid that promotes epithelial wound repair - from 24-72 hpf did not mitigate the prevalence of TPHP-induced epidermal folds within the yolk sac epithelium when embryos were exposed within high ionic strength exposure media. Finally, we found that the pericardial area and body length of embryos exposed to 5 mu M TPHP from 24-72 hpf were similar to vehicle-treated embryos at 120 hpf following transfer to clean water and depuration of TPHP from 72-120 hpf. Overall, our findings suggest that (1) the ionic strength of exposure media may influence the baseline physiology of zebrafish embryos; (2) TPHP does not cause direct injury to the embryonic epidermis; and (3) TPHP-induced effects on pericardial area and body length are reversible 48 h after transferring embryos to clean water.

We present a multiband study of FRB 20180916B, a repeating source with a 16.3 day periodicity. We report the detection of four, one, and seven bursts from observations spanning 3 days using the upgraded Giant Metrewave Radio Telescope (300–500 MHz), the Canadian Hydrogen Intensity Mapping Experiment (400–800 MHz) and the Green Bank Telescope (600–1000 MHz), respectively. We report the first ever detection of the source in the 800–1000 MHz range along with one of the widest instantaneous bandwidth detections (200 MHz) at lower frequencies. We identify 30 μ s wide structures in one of the bursts at 800 MHz, making it the lowest frequency detection of such structures for this fast radio burst thus far. There is also a clear indication of high activity of the source at a higher frequency during earlier phases of the activity cycle. We identify a gradual decrease in the rotation measure over two years and no significant variations in the dispersion measure. We derive useful conclusions about progenitor scenarios, energy distribution, emission mechanisms, and variation of the downward drift rate of emission with frequency. Our results reinforce that multiband observations are an effective approach to study repeaters, and even one-off events, to better understand their varying activity and spectral anomalies.

The goal of the search for extraterrestrial intelligence (SETI) is the detection of nonhuman technosignatures, such as technology-produced emission in radio observations. While many have speculated about the character of such technosignatures, radio SETI fundamentally involves searching for signals that not only have never been detected, but also have a vast range of potential morphologies. Given that we have not yet detected a radio SETI signal, we must make assumptions about their form to develop search algorithms. The lack of positive detections also makes it difficult to test these algorithms' inherent efficacy. To address these challenges, we present setigen, a Python-based, open-source library for heuristic-based signal synthesis and injection for both spectrograms (dynamic spectra) and raw voltage data. setigen facilitates the production of synthetic radio observations, interfaces with standard data products used extensively by the Breakthrough Listen project, and focuses on providing a physically motivated synthesis framework compatible with real observational data and associated search methods. We discuss the core routines of setigen and present existing and future use cases in the development and evaluation of SETI search algorithms.

Several classes of sources are known to emit different messengers. Among them, transient sources are a special case, due to their serendipitous occurrence, time variability and duration on different timescales. They are associated with explosive and catastrophic events where very compact objects like neutron stars and black holes are involved. The difficulty of observing such elusive and possibly short-lasting events requires a fast reaction and a well-organized alert network between different experiments. In order to characterize them in the best possible way, instruments with a wide field of view should serve as external triggers for facilities with small sky coverage. MAGIC, as a Cherenkov telescope, belongs to the latter category. The search for transients by MAGIC is possible thanks to an automatic alert system listening to the alerts sent by the Gamma-ray Coordinate Network (GCN). In this contribution we describe the MAGIC alert system, which was designed mainly for the follow-up of Gamma-Ray Bursts in its initial conception. The alert system was recently updated in a multi-messenger context, receiving alerts also from neutrino and GW observatories. Finally we will present the MAGIC program for transient sources and how it was adapted in the current multi-wavelength and multi-messenger panorama.

The MAGIC telescopes are a system of two imaging atmospheric Cherenkov telescopes designed to observe very-high-energy y rays. MAGIC utilizes a large reflective surface and photodetectors with ultrafast time response to capture Cherenkov photons. These features, together with the dedicated system installed in the central photomultiplier tube of their camera, so-called central pixel system (CPS), turn MAGIC into a suitable telescope to study high-speed optical astronomy in the millisecond (ms) regime. We report on the status of the CPS currently mounted in the MAGIC-II camera, its performance and calibration to demonstrate the sensitivity of MAGIC-II to ms optical pulses, for both transient and periodic signals, and discuss its potential over several science cases. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.