ChatGPT scores a bad birdie in counting gravitational-wave chirps

How many gravitational-wave observations from compact object mergers have we seen to date? This seemingly simple question has a surprisingly complex answer that even ChatGPT struggles to answer. To shed light on this, we present a database with the literature's answers to this question. We find values spanning 67-100 for the number of detections from double compact object mergers to date, emphasizing that the exact number of detections is uncertain and depends on the chosen data analysis pipeline and underlying assumptions. We also review the number of gravitational-wave detections expected in the coming decades with future observing runs, finding values up to millions of detections per year in the era of Cosmic Explorer and Einstein Telescope. We present a publicly available code to visualize the detection numbers, highlighting the exponential growth in gravitational-wave observations in the coming decades and the exciting prospects of gravitational-wave astrophysics. See http://www.broekgaarden.nl/floor/wordpress/elementor-967/. We plan to keep this database up-to-date and welcome comments and suggestions for additional references.Comment: 1 April submission, with fun videos for visualizing the landscape of gravitational waves! (they are awesome!) See http://www.broekgaarden.nl/floor/wordpress/elementor-967

Simulated Versus Observed Cluster Eccentricity Evolution

The rate of galaxy cluster eccentricity evolution is useful in understanding large scale structure. Rapid evolution for $z <$ 0.13 has been found in two different observed cluster samples. We present an analysis of projections of 41 clusters produced in hydrodynamic simulations augmented with radiative cooling and 43 clusters from adiabatic simulations. This new, larger set of simulated clusters strengthens the claims of previous eccentricity studies. We find very slow evolution in simulated clusters, significantly different from the reported rates of observational eccentricity evolution. We estimate the rate of change of eccentricity with redshift and compare the rates between simulated and observed clusters. We also use a variable aperture radius to compute the eccentricity, r$_{200}$. This method is much more robust than the fixed aperture radius used in previous studies. Apparently radiative cooling does not change cluster morphology on scales large enough to alter eccentricity. The discrepancy between simulated and observed cluster eccentricity remains. Observational bias or incomplete physics in simulations must be present to produce halos that evolve so differently.Comment: ApJ, in press, minor revision

STROOPWAFEL: Simulating rare outcomes from astrophysical populations, with application to gravitational-wave sources

Gravitational-wave observations of double compact object (DCO) mergers are providing new insights into the physics of massive stars and the evolution of binary systems. Making the most of expected near-future observations for understanding stellar physics will rely on comparisons with binary population synthesis models. However, the vast majority of simulated binaries never produce DCOs, which makes calculating such populations computationally inefficient. We present an importance sampling algorithm, STROOPWAFEL, that improves the computational efficiency of population studies of rare events, by focusing the simulation around regions of the initial parameter space found to produce outputs of interest. We implement the algorithm in the binary population synthesis code COMPAS, and compare the efficiency of our implementation to the standard method of Monte Carlo sampling from the birth probability distributions. STROOPWAFEL finds $\sim$25-200 times more DCO mergers than the standard sampling method with the same simulation size, and so speeds up simulations by up to two orders of magnitude. Finding more DCO mergers automatically maps the parameter space with far higher resolution than when using the traditional sampling. This increase in efficiency also leads to a decrease of a factor $\sim$3-10 in statistical sampling uncertainty for the predictions from the simulations. This is particularly notable for the distribution functions of observable quantities such as the black hole and neutron star chirp mass distribution, including in the tails of the distribution functions where predictions using standard sampling can be dominated by sampling noise.Comment: Accepted. Data and scripts to reproduce main results is publicly available. The code for the STROOPWAFEL algorithm will be made publicly available. Early inquiries can be addressed to the lead autho

Geogenic element behaviour in soil-rainwater interaction at Mt Etna, Sicily: preliminary results

Active volcanoes emit considerable amounts of contaminants such as As, Se and V. Previous studies have shown that the volcanic activity at Mt Etna (Sicily) has a strong influence on local rainwater compositions. However to date, the behaviour of trace elements in the soils around Mt Etna is poorly understood. 4-hr batch experiments have been performed with 1:5 soil solutions of air-dried soil (fraction <2 mm) and synthetic (acid) rainwater (using either deionized water with a pH of ~6 or a ~500 ppm of sulphuric acid solution with a pH of ~2). In general trace element concentrations are more enriched in soil solutions with low pH (e.g. enrichment factor (EF) acid compared to neutral soil solution is up to 4.3x102 for V, 2.5x102 for As and 50 for Se). However, it seems that the EF especially for As and V has a correlation with the distance to the crater. Additional, some soils located downwind of the volcano have EFs smaller than 1 (i.e. the elements are more enriched in neutral rainwater), for several elements like V, As and Se. For As and V the EF seems to be vary with distance to the crater. Some possible explanations for these trends will be discussed. These results might have important implications for the chemical composition of the Etnean aquifer, the only water resource to the one million inhabitants around Mt Etna, as well as the bioavailability and therefore potential toxicity through agricultural activities, essential to the local economy

Rainwater-induced leaching of selenium, arsenic and vanadium from Etnean volcanic soils

Active volcanoes emit considerable amounts of contaminants such as As, Se and V. Mount Etna is the biggest volcano of Europe and an excellent geochemical site to study water-soil processes. Due to its volcanic activity, the rainwater has a strong compositional gradient, both in time and space. At present, the behaviour of trace elements in the soils around Mt Etna is poorly understood. To determine the influence of the rainwater pH on the potential mobilization of geogenic pollutants, batch experiments have been performed with synthetic rainwater for 25 soils collected along the flanks of the volcano. Our results show that: i) The maximum concentrations in the leaching solutions are higher for acid rain than for neutral rain (e.g. 7.7 vs 1.3 mg/L for Se). ii) With neutral rain conditions the soils upwind from the volcano have higher concentrations of Se than those downwind (up to 1.3 mg/L compared to ≤0.3 mg/L for the other samples). This trend is less clear for As and V. iii) For soils collected from 2 to 10 km downwind of the craters, Se concentrations in acid rain leachates decrease one order of magnitude with increasing distance. A similar pattern is also observed upwind from the volcano. For As and V no clear relationship between concentrations and location with respect to the volcanic craters is observed. Both i) and ii) result in a low pH dependence for samples upwind from the volcano. The biggest difference between acid and neutral leaching for As and V is observed for a sample 2 km downwind from the craters. The observed patterns are influenced by potential controlling factors, such as organic matter content, total concentrations, mineralogy, influence of the volcanic plume, etc. Our results have implications for the chemical composition of the Etnean aquifer, the only water resource to the one million inhabitants around Mt Etna, as well as for the bioavailability and potential toxicity through agricultural activities, essential to the local economy

Tooth loss in Sjögren?s syndrome patients compared to age and gender matched controls

To analyze the prevalence and location of tooth loss in Sjögren?s syndrome (SS) patients and compare them with an age- and gender-matched control group. Dental charts and x-rays of 108 (SS) patients were retrieved from an academic dental center and special care dentistry department. For each SS patient, an age- and gender-matched non-SS patient was randomly selected. Medication, number of extractions and date and location of extractions were assessed. Differences between SS and non-SS patients were analyzed using Mann-Whitney U tests, Chi-square tests and Fisher?s exact tests. Significantly more SS patients were edentulous compared to the non-SS group (14.8% versus 1.9%, p = 0.001). SS patients had a 61% higher risk to have experienced one or more extractions than control patients. In the SS group, there was a non-significant tendency for more maxillary teeth to have been extracted than mandibular teeth (42:34). In the control group, the number of extractions in the maxilla and mandible were comparable (21:20). When divided into sextants, the number of SS patients with one or more extractions was significantly higher than for non-SS patients for each sextant (p = 0.001 to p = 0.032). The largest difference in the proportion of patients with one or more extractions between the SS and non-SS patients occurred in the upper anterior sextant (3.4 times more frequent). SS patients are more prone to experience dental extractions compared to patients without SS. It could be speculated that this is related to a decreased salivary secretion

Ninety minutes to reduce one's intention to eat meat : a preliminary experimental investigation on the effect of watching the Cowspiracy documentary on intention to reduce meat consumption

Whereas, past research has shown that using environmental arguments to reduce meat intake are unsuccessful in awareness campaigns, popular documentaries might have the potential to successfully change the public awareness of the environmental implications of meat consumption today. This preliminary study aimed to provide first empirical evidence of the potential effects of watching a popular documentary on a less-known environmental topic among a population that are habitual performers of the behavior under discussion. More precisely, the effects of watching “Cowspiracy: The Sustainability Secret” on the awareness of the environmental implications of meat consumption, the attitude toward eating less meat, and the intention to eat less meat in young adults who consume meat on an (almost) daily basis was studied. The potential impact of Cowspiracy was investigated from the Integrated Change Model perspective. Paper-and-pencil questionnaires were administered to N = 47 participants aged between 19 and 32 before and after watching either Cowspiracy (experimental group, n = 26) or Planet Earth (control group, n = 21). Controlling for the influence of predisposing factors (sociodemographic characteristics gender, age, and socioeconomic status), the results show that watching a popular documentary about the environmental impact of meat production (Cowspiracy) can have a significant effect on the awareness of the environmental consequences of meat consumption, the attitude toward eating less meat, and the intention to reduce meat consumption of young (almost) daily meat eaters. However, results should be interpreted with caution, given the preliminary nature of our study

The Shape of Galaxy Cluster Dark Matter Haloes: Systematics of Its Imprint on Cluster Gas, and Comparison to Observations

(Abridged) We study predictions for galaxy cluster observables that can test the statistics of dark matter halo shapes expected in a flat LCDM universe. We present a simple analytical model for the prediction of cluster-scale X-ray observations, approximating clusters as isothermal systems in hydrostatic equilibrium, and dark matter haloes as ellipsoids with uniform axial ratios. We test the model against high-resolution, hydrodynamic cluster simulations to gauge its reliability. We find that this simple prescription does a good job of predicting the distribution of cluster X-ray ellipticities compared to the simulations as long as one focuses on cluster regions that are less sensitive to recent mergers. Based on this simple model, the distribution of cluster-size halo shapes expected in the concordance LCDM cosmology implies an X-ray ellipticity distribution with a mean of 0.32 +- 0.01 and a scatter of 0.14 +- 0.01 for the mass range (1-4)x10^{14} Msun/h. We find it important to include the mass dependence of halo shape to make comparisons to observational samples that contain many, very massive clusters. We analyse the systematics of four observational samples of cluster ellipticities and find that our results are statistically compatible with observations. In particular, we find remarkably good agreement between two recent ROSAT samples and LCDM predictions that DO NOT include gas cooling. We also test how well our analytical model can predict Sunyaev-Zel'dovich decrement maps and find that it is less successful although still useful; the model does not perform as well as a function of flux level in this case because of the changing triaxiality of dark matter haloes as a function of radial distance. Both this effect and the changing alignment of isodensity shells of dark matter haloes leave an imprint on cluster gas...Comment: 16 pages, 9 figures; corrected typo (no result affected) submitted to MNRA

Volcanic signature of volatile trace elements on atmospheric deposition at Mt. Etna, Italy

Volcanic volatiles and aerosol emitted into the atmosphere ultimately fall on the Earth’s surface as wet or dry deposition, and they can influence the environment and the ecosystems at local and regional scales. Therefore, atmospheric deposition plays a key-role in the geochemical cycles, redistributing volcanogenic elements to the ground. For this reason, estimating the volcanogenic trace element fluxes from the atmosphere to the surface is necessary for a better knowledge of the environmental impact of the volcanic emissions. Nevertheless, from a literature review, we have recognized the scarcity of investigation on trace element deposition in the surroundings of active volcanoes. Here, we present a chemical characterization of bulk deposition around Mt. Etna, Italy, including both major and many trace elements. Bulk depositions were collected approximately fortnightly, from April 2006 to December 2007, using a network of five rain gauges, located at various altitudes on the upper flanks around the summit craters of the volcano. For most elements highest concentrations have been found close to the emission vent, confirming the prevailing volcanic contribution to rainwater composition close to the summit craters. Comparison with contemporaneously collected plume emissions shows that deposition processes produce no evident element-to-element fractionation. By contrast, comparison with whole rock composition indicates a contrasting behaviour between volatile elements, which are highly-enriched in rainwater, and refractory elements, which have low rainwater/whole rock concentration ratios. Chemical concentrations in bulk deposition were used to estimate the deposition rates of a large suite of elements. Deposition rates for volatile trace elements like Se, As, and Cd range from 1.7, 1.2 and 0.9 µg m-2 day-1 nearby to the summit vents, to 0.5, 0.3, and 0.1 µg m-2 day-1 at the local background site on the upwind western sector

Leadership, selfdevelopment and communication

Vi er inne i en tid med stadig forandringer. Teknologien utvikler seg hele tiden, og det stilles høyere krav til de som leder det. Men hva med menneskene bak forandringene? Vi oversvømmes av oppskrifter på hvordan vi kan skape oss et vellykket liv og arbeidsliv. Aviser, ledelsesbøker, seminarer, selvhjelpskurs er fulle av det. Oppskriftene er generelle, og de tar ikke hensyn til hvem vi er som enkeltpersoner, selv om de handler om ditt liv og din karriere. Det er viktig å ha en organisasjon hvor de ansatte skjønner hva de holder på med og som mestrer balansegangen mellom utfordringer og løsninger. Det krever at vi hele tiden er i aktivitet. Vi skal i denne oppgaven se på selvutvikling i forhold til kommunikasjon og ledelse, og komme litt i dybden av hva som skjer med de som har vært på selvutviklingskurs. Problemstillingen vår er: Hvordan blir kommunikasjonen etter selvutviklingskurs, og hva slags nytte drar organisasjonen av dette? Hvordan blir evnen til å lede seg selv? Det er fortsatt stor skepsis til selvutviklingskurs, og vi vil finne ut om det kan være en del av den aktiviteten som skal til for å lykkes som leder. God lesingEngelsk: We are in the midst of a time of constant change. Technology is continually developing and higher demands are required from the ones leading the process. But what the person behind the changes? We are drowning in recepies on how to create a successful life and corporate life. Newspapers, leaderchip books, seminars and self help courses are full of it. The receipes are general and do not consider who we are as individuals even if the receipies deal with your life and career. It is important having an organisation where the employees understand what they are doing and who cope with the balance better challenges and solutions. That demands constant activity. In this case we are looking at self development in regards to communication and leadership, and delve into what happens to those who attended self development courses. Our questions are: How is the communication after self development courses and how is it useful to the organisation? How is the capability of leading yourself? There is still much doubt and scepticism towards self development courses and we would like to find out if that could be a necessary activity to succeed as a leader. Enjoy