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In May 2016 a Norovirus (NoV) gastroenteritis outbreak involved a high school class visiting a seaside resort near Taormina (Mascali, Sicily). Twenty-four students and a teacher were affected and 17 of them showed symptoms on the second day of the journey, while the others got ill within the following 2 days. Symptoms included vomiting, diarrhoea and fever, and 12 students required hospitalisation. Stool samples tested positive for NoV genome by Real-Time polymerase chain reaction assay in all 25 symptomatic subjects. The GII.P2/GII.2 NoV genotype was linked to the outbreak by ORF1/ORF2 sequence analysis. The epidemiological features of the outbreak were consistent with food/waterborne followed by person-to-person and/or vomit transmission. Food consumed at a shared lunch on the first day of the trip was associated to illness and drinking un-bottled tap water was also considered as a risk factor. The analysis of water samples revealed the presence of bacterial indicators of faecal contamination in the water used in the resort as well as in other areas of the municipal water network, linking the NoV gastroenteritis outbreak to tap water pollution from sewage leakage. From a single water sample, an amplicon whose sequence corresponded to the capsid genotype recovered from patients could be obtained.
Nitrogen fertilization of silage maize in Central Italy is typically carried out with two applications at early stages of crop development: 2nd (V2) and 6th (V6) leaf respectively. In such conditions, the crop has not yet fully covered the soil and proximal or remote sensing of the canopy is hindered by the strong soil background signal. There is thus great interest in rapid and inexpensive approaches to N fertilization prescription. Therefore, an indirect method for inferring information on yield potential and soil variability, through a field-based clustering of multi-temporal satellite data, has been developed using archive Landsat images to identify temporally constant patterns. This method is potentially useful for the creation of prescription maps. The usefulness of the method was evaluated during an N fertilisation field trial in Maccarese (Central Italy), in 2016. At the V2 stage, both uniform and variable rate applications were performed and compared. A pseudo-cross variogram and a standardized ordinary co-kriging methodology was used to highlight spatially variable significant differences among the treatments.
The majority of extra-solar planets have been discovered (or confirmed after follow-up) through radial-velocity (RV) surveys. Using ground-based spectrographs such as High Accuracy Radial Velocity Planetary Search (HARPS) and HARPS-North, it is now possible to detect planets that are only a few times the mass of the Earth. However, the presence of dark spots on the stellar surface produces RV signals that are very similar in amplitude to those caused by orbiting low-mass planets. Disentangling these signals has thus become the biggest challenge in the detection of Earth-mass planets using RV surveys. To do so, we use the star's lightcurve to model the RV variations produced by spots. Here we present this method and show the results of its application to CoRoT-7.
Since the discovery of the transiting Super-Earth CoRoT-7b, several investigations have been made of the number and precise masses of planets present in the system, but they all yield different results, owing to the star's high level of activity. Radial velocity (RV) variations induced by stellar activity therefore need to be modelled and removed to allow a reliable detection of all planets in the system. We re-observed CoRoT-7 in January 2012 with both HARPS and the CoRoT satellite, so that we now have the benefit of simultaneous RV and photometric data. We fitted the off-transit variations in the CoRoT lightcurve using a harmonic decomposition similar to that implemented in Queloz et al. (2009). This fit was then used to model the stellar RV contribution, according to the methods described by Aigrain et al. (2011). This model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b and CoRoT-7c. We also assess the evidence for the presence of one or two additional planetary companions.
We present radial-velocity measurements (RV) obtained in one of the numbers of programs underway to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Observatoire de Haute-Provence. Targets were selected from catalogs observed with ELODIE, which had been mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years.
High-precision radial velocity measurements have suffered from stellar spots effects for more than one decade. With the advent of high-resolution infra-red spectrographs, one is allowed to move into a new spectral domain where the influence of these stellar phenomena on measurements is significantly reduced. We present the first results of our CRIRES campaign on TW Hya, around which a periodic optical radial velocity variation was found and attributed to a planet. Our work showed that the signal is not present in the infra-red, pointing to a cold spot instead of to a planet as the explanation for the different data sets. This campaign
demonstrates the power of this new approach and shows that CRIRES can deliver high-precision radial velocity measurements.
Charge Transfer Inefficiency (CTI) is a well known effect of charge-coupled
devices (CCD). The charge transfer from one pixel to the next is not perfect
and is quantified by the fraction of charge successfully moved (clocked) between
adjacent pixels. The amplitude of this effect depends on the signal level
inside the pixel. In the context of high-precision radial velocity measurements
using cross-dispersed echelle spectrograph, this CTI effect on a CCD
recording spectral orders may introduce associated spectral lines shifts.
Indeed if the signal level recorded on the spectra is changing, the CTI amplitude
will change affecting the associated centroid of all spectral lines.
Such effect may introduced radial velocity shifts of several m s-1.
We describe here CTI effect which is affecting the SOPHIE spectrograph installed on
the 1.93-m telescope of Observatoire de Haute Provence (OHP). We calibrated the
effect thanks to the Thorium-Argon
lines and we applied a software correction on the spectra in order to assess
the charge lost during the readout process on all pixels.
The Doppler technique has continuously improved its precision during the past two decades, attaining the level of 1 ms−1. The increasing precision opened the way to the discovery of the first extrasolar planet, and later, to the exploration of a large range of orbital parameters of extrasolar planets. This ability to detect and characterize in great detail companions down to Neptune-mass planets has provided many new and unique inputs for the understanding of planet formation and evolution. In addition, the success of the Doppler technique introduced a great dynamic in the whole domain, allowing the exploration of new possibilities.
Nowadays, the Doppler technique is no longer the only means to discover extrasolar planets. The performance of new instruments, like the High Accuracy Radial-velocity Planet Searcher (HARPS), has shown that the potential of the Doppler technique has not been exhausted; Earth-mass planets are now within reach. In the future, radial velocities will also play a fundamental role in the follow-up and characterization of planets discovered by means of other techniques—for transit candidates, in particular. We think, therefore, that the follow-up of candidates provided by, e.g., the COnvection, ROtation and planetary Transits (COROT) and Kepler space telescopes, will be of primary importance.
The SOPHIE Consortium started a large program of exoplanets search and characterization in the Northern hemisphere with the new spectrograph SOPHIE at the 1.93-m telescope of Haute-Provence Observatory, France. The objectives of this program are to characterize the zoo of exoplanets and to bring strong constraints on their processes of formation and evolution using the radial velocity technique. We present here new SOPHIE measurements of the transiting planet host star XO-3. This allowed us to observe the Rossiter-McLaughlin effect and to refine the parameters of the planet. The unusual shape of the radial velocity anomaly during the transit provides a hint for a nearly transverse Rossiter-McLaughlin effect. The sky-projected angle between the planetary orbital axis and the stellar rotation axis should be λ = 70° ± 15° to be compatible with our observations. This suggests that some close-in planets might result from gravitational interaction between planets and/or stars rather than migration. This result requires confirmation by additional observations.
The HARPS search for low-mass extrasolar planets has been ongoing for more than 4 years, targeting originally about 400 bright FGK dwarfs in the solar neighbourhood. The published low-mass planetary systems coming from this survey are fully confirmed by subsequent observations, which demonstrate the sub-m/s long-term stability reached by HARPS. The complex RV curves of these systems have led us to focus on a smaller sample of stars, accumulating more data points per star. We perform a global search in our data to assess the existence of the large population of ice giants and super-Earths predicted by numerical simulations of planet formation. We indeed detect about 45 candidates having minimum masses below 30 M⊕ and orbital periods below 50 days. These numbers are preliminary since the existence of these objects has to be confirmed by subsequent observations. However, they indicate that about 30% of solar-type stars may have such close-in, low-mass planets. Some emerging properties of this low-mass population are presented. We finally discuss the prospects for finding transiting objects among these candidates, which may possibly yield the first nearby, transiting super-Earth.
Exoplanet search programs need to study how to disentangle radial-velocity (RV) variations due to Doppler motion and the noise induced by stellar activity. We monitored the active K2V HD 189733 with the high-resolution SOPHIE spectrograph (OHP, France). We refined the orbital parameters of HD 189733b and put limitations on the eccentricity and on a long-term velocity gradient. We subtracted the orbital motion of the planet and compared the variability of activity spectroscopic indices (HeI, Hα, Ca II H&K lines) to the evolution of the RV residuals and the shape of spectral lines. All are in agreement with an active stellar surface in rotation. We used such correlations to correct for the RV jitter due to stellar activity. This results in achieving a high precision on the orbital parameters, with a semi-amplitude: K=200.56±0.88m⋅s−1 and a derived planet mass of MP=1.13±0.03 MJup.
We describe the ongoing hardware and software developments that shall enable the ESO VLTI to perform narrow-angle differential delay astrometry in K-band with an accuracy of up to 10 μarcsec. The ultimate goal of these efforts is to perform an astrometric search for extrasolar planets around nearby stars.
The combination of the collecting power of an ELT with an ultra-stable high resolution spectrograph opens up the possibility to measure for the first time directly the dynamical effect of the acceleration of the Universe. CODEX will also provide unique opportunities for advance in many other branches of astrophysics. The CODEX design is based on an array of several identical spectrographs. It is highly modular and can be easily adapted to a large range of sky apertures and telescope diameters. CODEX is designed to work as a seeing limited instrument. The requirements for the telescope are moderate and clearly identified.
We present radial-velocity data measurements for 4 solar-type stars (HD 6434, HD 19994, HD 92788 and HD 121504) harboring new detected planetary companions. The measurements were obtained with the CORALIE echelle spectrograph mounted on the 1.2–m “Leonard Euler” Swiss telescope at ESO–LaSilla Observatory (Chile). The minimum masses inferred for the planets are m2 sin i = 0.48, 2.0, 3.81 and 0.89MJup, respectively.
Since the discovery of 51 Peg by Mayor & Queloz (1995) about 50 extra-solar planets have been discovered by means of the Doppler technique, and much more will follow. In future the goal will be to detect even lighter planets and/or planets with longer orbital periods, which may induce changes of only few m/s on the radial velocity of their parent star. Therefore very high performance instruments will be required. In view of the realization of HARPS (Pepe et al. 2000), the high-accuracy RV spectrograph for the ESO 3.6-m telescope dedicated to extra-solar planet search, we are investigating the accuracy limits and possible error sources. First results are presented in this paper.
We report the discovery of an extrasolar planetary system with two Saturnian planets around the star HD 83443. The new planetary system is unusual by more than one aspect, as it contains two very low–mass gaseous giant planets, both on very tight orbits. Among the planets detected so far, the inner planet has the smallest semi–major axis (0.038 AU) and period (2.985 days) whereas the outer planet is the lightest one with m2 sin i = 0.53 MSat. A preliminary dynamical study confirms the stability of the system.
For the past two decades, prehospital trauma care has been addressed almost generically in terms of the related approaches to epidemiology, research, and management. However, evolving directions in research have helped emergency medical services (EMS) practitioners to delineate more focused treatment strategies according to the mechanism of injury, anatomic involvement, and the patient's clinical condition. Recent studies in the areas of trauma-associated circulatory arrest, severe blunt head injury, and post-traumatic hemorrhage following penetrating truncal injury suggest that current standard approaches to patient care should be reconsidered. In turn, this need for re-examination of trauma management strategies calls for the development of appropriate evaluation tools within EMS systems. Proper research design is dependent upon several key issues including: 1) the type of study (system study versus examination of a specific intervention); 2), the population under study; 3) physiological and anatomical scoring method; 4) prospective definitions of interventions and meaningful outcome variables (both morbidity and mortality; 5) relative outcome compared to known standards; and 6) prospective determination of statistical requirements.
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