2,259 research outputs found

    EUSO-Offline: A comprehensive simulation and analysis framework

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    International audienceThe complexity of modern cosmic ray observatories and therich data sets they capture often require a sophisticated softwareframework to support the simulation of physical processes, detectorresponse, as well as reconstruction and analysis of real andsimulated data. Here we present the EUSO-Offline framework. Thecode base was originally developed by the Pierre AugerCollaboration, and portions of it have been adopted by othercollaborations to suit their needs. We have extended this softwareto fulfill the requirements of Ultra-High Energy Cosmic Raydetectors and very high energy neutrino detectors developed for theJoint Exploratory Missions for an Extreme Universe Observatory(JEM-EUSO). These path-finder instruments constitute a program tochart the path to a future space-based mission like POEMMA. Forcompleteness, we describe the overall structure of the frameworkdeveloped by the Auger collaboration and continue with a descriptionof the JEM-EUSO simulation and reconstruction capabilities. Theframework is written predominantly in modern C++ (compliled againstC++17) and incorporates third-party libraries chosen based onfunctionality and our best judgment regarding support andlongevity. Modularity is a central notion in the framework design, arequirement for large collaborations in which many individualscontribute to a common code base and often want to compare differentapproaches to a given problem. For the same reason, the framework isdesigned to be highly configurable, which allows us to contend witha variety of JEM-EUSO missions and observation scenarios. We alsodiscuss how we incorporate broad, industry-standard testing coveragewhich is necessary to ensure quality and maintainability of arelatively large code base, and the tools we employ to support amultitude of computing platforms and enable fast, reliableinstallation of external packages. Finally, we provide a fewexamples of simulation and reconstruction applications usingEUSO-Offline

    EUSO-Offline: A comprehensive simulation and analysis framework

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    International audienceThe complexity of modern cosmic ray observatories and therich data sets they capture often require a sophisticated softwareframework to support the simulation of physical processes, detectorresponse, as well as reconstruction and analysis of real andsimulated data. Here we present the EUSO-Offline framework. Thecode base was originally developed by the Pierre AugerCollaboration, and portions of it have been adopted by othercollaborations to suit their needs. We have extended this softwareto fulfill the requirements of Ultra-High Energy Cosmic Raydetectors and very high energy neutrino detectors developed for theJoint Exploratory Missions for an Extreme Universe Observatory(JEM-EUSO). These path-finder instruments constitute a program tochart the path to a future space-based mission like POEMMA. Forcompleteness, we describe the overall structure of the frameworkdeveloped by the Auger collaboration and continue with a descriptionof the JEM-EUSO simulation and reconstruction capabilities. Theframework is written predominantly in modern C++ (compliled againstC++17) and incorporates third-party libraries chosen based onfunctionality and our best judgment regarding support andlongevity. Modularity is a central notion in the framework design, arequirement for large collaborations in which many individualscontribute to a common code base and often want to compare differentapproaches to a given problem. For the same reason, the framework isdesigned to be highly configurable, which allows us to contend witha variety of JEM-EUSO missions and observation scenarios. We alsodiscuss how we incorporate broad, industry-standard testing coveragewhich is necessary to ensure quality and maintainability of arelatively large code base, and the tools we employ to support amultitude of computing platforms and enable fast, reliableinstallation of external packages. Finally, we provide a fewexamples of simulation and reconstruction applications usingEUSO-Offline

    The SPIRou Legacy Survey Rotation period of quiet M dwarfs from circular polarization in near-infrared spectral lines: I. The SPIRou APERO analysis

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    Context. The rotation period of stars is an important parameter along with mass, radius, effective temperature. It is an essential parameter for any radial velocity monitoring, as stellar activity can mimic the presence of a planet at the stellar rotation period. Several methods exist to measure it, including long sequences of photometric measurements or temporal series of stellar activity indicators. Aims. Here, we use the circular polarization in near-infrared spectral lines for a sample of 43 quiet M dwarfs and compare the measured rotation periods to those obtained with other methods. Methods. From Stokes V spectropolarimetric sequences observed with SPIRou at CFHT and the data processed with the APERO pipeline, we compute the least squares deconvolution profiles using different masks of atomic stellar lines with known Land\'e factor appropriate to the effective temperature of the star. We derive the longitudinal magnetic field to examine its possible variation along the 50 to 200 observations of each star. For determining the stellar rotation period, we apply a Gaussian process regression enabling us to determine the rotation period of stars with evolving longitudinal field. Results. Among the 43 stars of our sample, we were able to measure a rotation period for 27 stars. For 8 stars, the rotation period was previously unknown. We find a good agreement of our rotation periods with periods found in the literature based on photometry and activity indicators and confirm that near-infrared spectropolarimetry is an important tool to measure rotation periods, even for magnetically quiet stars. Furthermore, we compute ages for 20 stars of our sample using gyrochronology

    Simulation studies for the Mini-EUSO detector

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    Mini-EUSO is a mission of the JEM-EUSO program flying onboard the International Space Station since August 2019. Since the first data acquisition in October 2019, more than 35 sessions have been performed for a total of 52 hours of observations. The detector has been observing Earth at night-time in the UV range and detected a wide variety of transient sources all of which have been modelled through Monte Carlo simulations. Mini-EUSO is also capable of detecting meteors and potentially space debris and we performed simulations for such events to estimate their impact on future missions for cosmic ray science from space. We show here examples of the simulation work done in this framework to analyse the Mini-EUSO data. The expected response of Mini-EUSO with respect to ultra high energy cosmic ray showers has been studied. The efficiency curve of Mini-EUSO as a function of primary energy has been estimated and the energy threshold for Cosmic Rays has been placed to be above 1021^{21} eV. We compared the morphology of several transient events detected during the mission with cosmic ray simulations and excluded that they can be due to cosmic ray showers. To validate the energy threshold of the detector, a system of ground based flashers is being used for end-to-end calibration purposes. We therefore implemented a parameterisation of such flashers into the JEM-EUSO simulation framework and studied the response of the detector with respect to such sources

    Characterizing planetary systems with SPIRou: M-dwarf planet-search survey and the multiplanet systems GJ 876 and GJ 1148

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    SPIRou is a near-infrared spectropolarimeter and a high-precision velocimeter. The SPIRou Legacy Survey collected data from February 2019 to June 2022, half of the time devoted to a blind search for exoplanets around nearby cool stars. The aim of this paper is to present this program and an overview of its properties, and to revisit the radial velocity (RV) data of two multiplanet systems, including new visits with SPIRou. From SPIRou data, we can extract precise RVs using efficient telluric correction and line-by-line measurement techniques, and we can reconstruct stellar magnetic fields from the collection of polarized spectra using the Zeeman-Doppler imaging method. The stellar sample of our blind search in the solar neighborhood, the observing strategy, the RV noise estimates, chromatic behavior, and current limitations of SPIRou RV measurements on bright M dwarfs are described. In addition, SPIRou data over a 2.5-year time span allow us to revisit the known multiplanet systems GJ~876 and GJ~1148. For GJ~876, the new dynamical analysis including the four planets is consistent with previous models and confirms that this system is deep in the Laplace resonance and likely chaotic. The large-scale magnetic map of GJ~876 over two consecutive observing seasons is obtained and shows a dominant dipolar field with a polar strength of 30~G, which defines the magnetic environment in which the inner planet with a period of 1.94~d is embedded. For GJ~1148, we refine the known two-planet model.Comment: accepted in A&

    The spatial association between environmental pollution and long-term cancer mortality in Italy

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    Tumours are nowadays the second world-leading cause of death after cardiovascular diseases. During the last decades of cancer research, lifestyle and random/genetic factors have been blamed for cancer mortality, with obesity, seden-tary habits, alcoholism, and smoking contributing as supposed major causes. However, there is an emerging consensus that environmental pollution should be considered one of the main triggers. Unfortunately, all this preliminary scien-tific evidence has not always been followed by governments and institutions, which still fail to pursue research on can-cer's environmental connections. In this unprecedented national-scale detailed study, we analyzed the links between cancer mortality, socio-economic factors, and sources of environmental pollution in Italy, both at wider regional and finer provincial scales, with an artificial intelligence approach. Overall, we found that cancer mortality does not have a random or spatial distribution and exceeds the national average mainly when environmental pollution is also higher, despite healthier lifestyle habits. Our machine learning analysis of 35 environmental sources of pollution showed that air quality ranks first for importance concerning the average cancer mortality rate, followed by sites to be reclaimed, urban areas, and motor vehicle density. Moreover, other environmental sources of pollution proved to be relevant for the mortality of some specific cancer types. Given these alarming results, we call for a rearrangement of the priority of cancer research and care that sees the reduction and prevention of environmental contamination as a priority action to put in place in the tough struggle against cancer

    An overview of the JEM-EUSO program and results

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    The field of UHECRs (Ultra-High energy cosmic Rays) and the understanding of particle acceleration in the cosmos, as a key ingredient to the behaviour of the most powerful sources in the universe, is of outmost importance for astroparticle physics as well as for fundamental physics and will improve our general understanding of the universe. The current main goals are to identify sources of UHECRs and their composition. For this, increased statistics is required. A space-based detector for UHECR research has the advantage of a very large exposure and a uniform coverage of the celestial sphere. The aim of the JEM-EUSO program is to bring the study of UHECRs to space. The principle of observation is based on the detection of UV light emitted by isotropic fluorescence of atmospheric nitrogen excited by the Extensive Air Showers (EAS) in the Earth’s atmosphere and forward-beamed Cherenkov radiation reflected from the Earth’s surface or dense cloud tops. In addition to the prime objective of UHECR studies, JEM-EUSO will do several secondary studies due to the instruments\u27 unique capacity of detecting very weak UV-signals with extreme time-resolution around 1 microsecond: meteors, Transient Luminous Events (TLE), bioluminescence, maps of human generated UV-light, searches for Strange Quark Matter (SQM) and high-energy neutrinos, and more. The JEM-EUSO program includes several missions from ground (EUSO-TA), from stratospheric balloons (EUSO-Balloon, EUSO-SPB1, EUSO-SPB2), and from space (TUS, Mini-EUSO) employing fluorescence detectors to demonstrate the UHECR observation from space and prepare the large size missions K-EUSO and POEMMA. A review of the current status of the program, the key results obtained so far by the different projects, and the perspectives for the near future are presented

    Microbiome preterm birth DREAM challenge: Crowdsourcing machine learning approaches to advance preterm birth research

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    Every year, 11% of infants are born preterm with significant health consequences, with the vaginal microbiome a risk factor for preterm birth. We crowdsource models to predict (1) preterm birth (PTB; <37 weeks) or (2) early preterm birth (ePTB; <32 weeks) from 9 vaginal microbiome studies representing 3,578 samples from 1,268 pregnant individuals, aggregated from public raw data via phylogenetic harmonization. The predictive models are validated on two independent unpublished datasets representing 331 samples from 148 pregnant individuals. The top-performing models (among 148 and 121 submissions from 318 teams) achieve area under the receiver operator characteristic (AUROC) curve scores of 0.69 and 0.87 predicting PTB and ePTB, respectively. Alpha diversity, VALENCIA community state types, and composition are important features in the top-performing models, most of which are tree-based methods. This work is a model for translation of microbiome data into clinically relevant predictive models and to better understand preterm birth

    Postoperative complications after pancreatoduodenectomy for malignancy: results from the Recurrence After Whipple’s (RAW) study

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    Background Pancreatoduodenectomy (PD) is associated with significant postoperative morbidity. Surgeons should have a sound understanding of the potential complications for consenting and benchmarking purposes. Furthermore, preoperative identification of high-risk patients can guide patient selection and potentially allow for targeted prehabilitation and/or individualized treatment regimens. Using a large multicentre cohort, this study aimed to calculate the incidence of all PD complications and identify risk factors. Method Data were extracted from the Recurrence After Whipple’s (RAW) study, a retrospective cohort study of PD outcomes (29 centres from 8 countries, 2012–2015). The incidence and severity of all complications was recorded and potential risk factors for morbidity, major morbidity (Clavien–Dindo grade > IIIa), postoperative pancreatic fistula (POPF), post-pancreatectomy haemorrhage (PPH) and 90-day mortality were investigated. Results Among the 1348 included patients, overall morbidity, major morbidity, POPF, PPH and perioperative death affected 53 per cent (n = 720), 17 per cent (n = 228), 8 per cent (n = 108), 6 per cent (n = 84) and 4 per cent (n = 53), respectively. Following multivariable tests, a high BMI (P = 0.007), an ASA grade > II (P II patients were at increased risk of major morbidity (P < 0.0001), and a raised BMI correlated with a greater risk of POPF (P = 0.001). Conclusion In this multicentre study of PD outcomes, an ASA grade > II was a risk factor for major morbidity and a high BMI was a risk factor for POPF. Patients who are preoperatively identified to be high risk may benefit from targeted prehabilitation or individualized treatment regimens
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