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result(s) for
"Rochat, S"
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Upper and Lower Respiratory Tract Viral Infections and Acute Graft Rejection in Lung Transplant Recipients
2010
Background. Lung transplant recipients are frequently exposed to respiratory viruses and are particularly at risk for severe complications. The aim of this study was to assess the association among the presence of a respiratory virus detected by molecular assays in bronchoalveolar lavage (BAL) fluid, respiratory symptoms, and acute rejection in adult lung transplant recipients. Methods. Upper (nasopharyngeal swab) and lower (BAL) respiratory tract specimens from 77 lung transplant recipients enrolled in a cohort study and undergoing bronchoscopy with BAL and transbronchial biopsies were screened using 17 different polymerase chain reaction—based assays. Results. BAL fluid and biopsy specimens from 343 bronchoscopic procedures performed in 77 patients were analyzed. We also compared paired nasopharyngeal and BAL fluid specimens collected in a subgroup of 283 cases. The overall viral positivity rate was 29.3% in the upper respiratory tract specimens and 17.2% in the BAL samples (P < .001). We observed a significant association between the presence of respiratory symptoms and positive viral detection in the lower respiratory tract (P = .012). Conversely, acute rejection was not associated with the presence of viral infection (odds ratio, 0.41; 95% confidence interval, 0.20–0.88). The recovery of lung function was significantly slower when acute rejection and viral infection were both present. Conclusions. A temporal relationship exists between acute respiratory symptoms and positive viral nucleic acid detection in BAL fluid from lung transplant recipients. We provide evidence suggesting that respiratory viruses are not associated with acute graft rejection during the acute phase of infection.
Journal Article
It's not only clients: Studying emotion work with clients and co-workers with an event-sampling approach
by
Rochat, Sylvie
,
Tschan, Franziska
,
Zapf, Dieter
in
Attitudes
,
Attitudes to work
,
Case studies
2005
A group of 78 young employees in service and non‐service professions reported 848 task related interactions at work over 1 week using a variant of the Rochester Interaction Record which measured emotion work requirements, emotional dissonance, and deviance. Multi‐level analyses showed that dissonance was more likely in interactions with customers, whereas deviance, that is, the violation of display rules by acting out one's felt emotion, was more likely in co‐worker interactions. Well‐being in the interaction was lower (a) for interactions with emotion work requirements, (b) for dissonance, even after controlling for felt negative emotions, and (c) for deviance. Negative emotion displayed partially mediated the relationship between deviance and well‐being. Regarding the relationship of more stable job related attitudes, psychosomatic complaints, and aggregated scores of social interactions, fewer effects were found than in questionnaire studies, which may be due to the fact that only interactions that lasted at least 10 minutes were assessed, as is customary in research with this instrument. Among the effects found, however, many involved proportions rather than frequency of interactions, which raises the possibility of balancing and legitimizing effects of non‐stressful interactions.
Journal Article
NAOMI: the adaptive optics system of the Auxiliary Telescopes of the VLTI
2019
The tip-tilt stabilisation system of the 1.8 m Auxiliary Telescopes of the Very Large Telescope Interferometer was never dimensioned for robust fringe tracking, except when atmospheric seeing conditions are excellent. Increasing the level of wavefront correction at the telescopes is expected to improve the coupling into the single-mode fibres of the instruments, and enable robust fringe tracking even in degraded conditions. We deployed a new adaptive optics module for interferometry (NAOMI) on the Auxiliary Telescopes. We present its design, performance, and effect on the observations that are carried out with the interferometric instruments.
The SPHERE infrared survey for exoplanets (SHINE). V. Complete observations, data reduction and analysis, detection performances, and final results
2025
During the past decade, state-of-the-art planet-finder instruments like SPHERE@VLT, coupling coronagraphic devices and extreme adaptive optics systems, unveiled, thanks to large surveys, around 20 planetary mass companions at semi-major axis greater than 10 astronomical units. Direct imaging being the only detection technique to be able to probe this outer region of planetary systems, the SPHERE infrared survey for exoplanets (SHINE) was designed and conducted from 2015 to 2021 to study the demographics of such young gas giant planets around 400 young nearby solar-type stars. In this paper, we present the observing strategy, the data quality, and the point sources analysis of the full SHINE statistical sample as well as snapSHINE. Both surveys used the SPHERE@VLT instrument with the IRDIS dual band imager in conjunction with the integral field spectrograph IFS and the angular differential imaging observing technique. All SHINE data (650 datasets), corresponding to 400 stars, including the targets of the F150 survey, are processed in a uniform manner with an advanced post-processing algorithm called PACO ASDI. An emphasis is put on the classification and identification of the most promising candidate companions. Compared to the previous early analysis SHINE F150, the use of advanced post-processing techniques significantly improved by one or 2 magnitudes (x3-x6) the contrast detection limits, which will allow us to put even tighter constraints on the radial distribution of young gas giants. This increased sensitivity directly places SHINE as the largest and deepest direct imaging survey ever conducted. We detected and classified more than 3500 physical sources. One additional substellar companion has been confirmed during the second phase of the survey (HIP 74865 B), and several new promising candidate companions are awaiting second epoch confirmations.
Revisiting the atmosphere of the exoplanet 51 Eridani b with VLT/SPHERE
2022
[Full abstract in the paper] We aim to better constrain the atmospheric properties of the directly imaged exoplanet 51~Eri~b by using a retrieval approach on higher signal-to-noise data than previously reported. In this context, we also compare the results of using the atmospheric retrieval code \\texttt{petitRADTRANS} vs a self-consistent model to fit atmospheric parameters. We present a higher signal-to-noise \\(YH\\) spectrum of the planet and revised \\(K1K2\\) photometry (M\\(_{K1} = 15.11 \\pm 0.04\\) mag, M\\(_{K2} = 17.11 \\pm 0.38\\) mag). The best-fit parameters obtained using an atmospheric retrieval differ from previous results using self-consistent models. In general, we find that our solutions tend towards cloud-free atmospheres (e.g. log \\(\\tau_{\\rm clouds} = -5.20 \\pm 1.44\\)). For our ``nominal'' model with new data, we find a lower metallicity ([Fe/H] \\(= 0.26\\pm\\)0.30 dex) and C/O ratio (\\(0.38\\pm0.09\\)), and a slightly higher effective temperature (T\\(_{\\rm{eff}} = 807\\pm\\)45 K) than previous studies. The surface gravity (log \\(g = 4.05\\pm0.37\\)) is in agreement with the reported values in the literature within uncertainties. We estimate the mass of the planet to be between 2 and 4 M\\(_{\\rm{Jup}}\\). When comparing with self-consistent models, we encounter a known correlation between the presence of clouds and the shape of the \\(P-T\\) profiles. Our findings support the idea that results from atmospheric retrievals should not be discussed in isolation, but rather along with self-consistent temperature structures obtained using the retrieval's best-fit parameters.
A dynamical measure of the black hole mass in a quasar 11 billion years ago
2024
Tight relationships exist in the local universe between the central stellar properties of galaxies and the mass of their supermassive black hole. These suggest galaxies and black holes co-evolve, with the main regulation mechanism being energetic feedback from accretion onto the black hole during its quasar phase. A crucial question is how the relationship between black holes and galaxies evolves with time; a key epoch to probe this relationship is at the peaks of star formation and black hole growth 8-12 billion years ago (redshifts 1-3). Here we report a dynamical measurement of the mass of the black hole in a luminous quasar at a redshift of 2, with a look back time of 11 billion years, by spatially resolving the broad line region. We detect a 40 micro-arcsecond (0.31 pc) spatial offset between the red and blue photocenters of the H\\(\\) line that traces the velocity gradient of a rotating broad line region. The flux and differential phase spectra are well reproduced by a thick, moderately inclined disk of gas clouds within the sphere of influence of a central black hole with a mass of 3.2x10\\(^8\\) solar masses. Molecular gas data reveal a dynamical mass for the host galaxy of 6x10\\(^11\\) solar masses, which indicates an under-massive black hole accreting at a super-Eddington rate. This suggests a host galaxy that grew faster than the supermassive black hole, indicating a delay between galaxy and black hole formation for some systems.
Characterization of a protein of the plastid inner envelope having homology to animal inorganic phosphate, chloride and organic-anion transporters
by
Petétot, Jean MacDonald-Comber
,
Rochat-Hacker, Sylvie
,
Poirier, Yves
in
Absorption. Translocation of ions and substances. Permeability
,
Agronomy. Soil science and plant productions
,
Amino Acid Sequence
2004
A protein from Arabidopsis thaliana (L.) Heynh. showing homology to animal proteins of the NaPi-1 family, involved in the transport of inorganic phosphate, chloride, glutamate and sialic acid, has been characterized. This protein, named ANTR2 (for anion transporters) was shown by chloroplast subfractionation to be localized to the plastid inner envelope in both A. thaliana and Spinacia oleracea (L.). Immunolocalization revealed that ANTR2 was expressed in the leaf mesophyll cells as well as in the developing embryo at the upturned-U stage. Five additional homologues of ANTR2 are found in the Arabidopsis genome, of which one was shown by green fluorescent protein (GFP) fusion to be also located in the chloroplast. All ANTR proteins share homology to the animal NaPi-1 family, as well as to other organic-anion transporters that are members of the Anion:Cation Symporter (ACS) family, and share the main features of transporters from this family, including the presence of 12 putative transmembrane domains and of a 7-amino acid motif in the fourth putative transmembrane domain. ANTR2 thus represent a novel protein of the plastid inner envelope that is likely to be involved in anion transport.
Journal Article
Constraining masses and separations of unseen companions to five accelerating nearby stars
2022
Aims. This work aims at constraining the masses and separations of potential substellar companions to five accelerating stars (HIP 1481, HIP 88399, HIP 96334, HIP 30314 and HIP 116063) using multiple data sets acquired with different techniques. Methods. Our targets were originally observed as part of the SPHERE/SHINE survey, and radial velocity (RV) archive data were also available for four of the five objects. No companions were originally detected in any of these data sets, but the presence of significant proper motion anomalies (PMa) for all the stars strongly suggested the presence of a companion. Combining the information from the PMa with the limits derived from the RV and SPHERE data, we were able to put constraints on the characteristics of the unseen companions. Results. Our analysis led to relatively strong constraints for both HIP 1481 and HIP 88399, narrowing down the companion masses to 2-5 M_Jup and 3-5 M_Jup and separations within 2-15 au and 3-9 au, respectively. Because of the large age uncertainties for HIP 96334, the poor observing conditions for the SPHERE epochs of HIP 30314 and the lack of RV data for HIP 116063, the results for these targets were not as well defined, but we were still able to constrain the properties of the putative companions within a reasonable confidence level. Conclusions. For all five targets, our analysis has revealed that the companions responsible for the PMa signal would be well within reach for future instruments planned for the ELT (e.g., MICADO), which would easily achieve the required contrast and angular resolution. Our results therefore represent yet another confirmation of the power of multi-technique approaches for both the discovery and characterisation of planetary systems.
A multiwavelength analysis of the spiral arms in the protoplanetary disk around WaOph 6
2021
[Full abstract in the paper] In recent years, protoplanetary disks with spiral structures have been detected in scattered light, millimeter continuum, and CO gas emission. The mechanisms causing these structures are still under debate. A popular scenario to drive the spiral arms is the one of a planet perturbing the material in the disk. However, if the disk is massive, gravitational instability is usually the favored explanation. Multiwavelength studies could be helpful to distinguish between the two scenarios. So far, only a handful of disks with spiral arms have been observed in both scattered light and millimeter continuum. We aim to perform an in-depth characterization of the protoplanetary disk morphology around WaOph 6 analyzing data obtained at different wavelengths, as well as to investigate the origin of the spiral features in the disk. We present the first near-infrared polarimetric observations of WaOph 6 obtained with SPHERE at the VLT and compare them to archival millimeter continuum ALMA observations. We traced the spiral features in both data sets and estimated the respective pitch angles. We discuss the different scenarios that can give rise to the spiral arms in WaOph 6. We tested the planetary perturber hypothesis by performing hydrodynamical and radiative transfer simulations to compare them with scattered light and millimeter continuum observations.