61 research outputs found
Effective dynamics of strongly dissipative Rydberg gases
We investigate the evolution of interacting Rydberg gases in the limit of strong noise and dissipation. Starting from a description in terms of a Markovian quantum master equation we derive effective equations of motion that govern the dynamics on a "coarse-grained" timescale where fast dissipative degrees of freedom have been adiabatically eliminated. Specifically, we consider two scenarios which are of relevance for current theoretical and experimental studies --- Rydberg atoms in a two-level (spin) approximation subject to strong dephasing noise as well as Rydberg atoms under so-called electromagnetically induced transparency (EIT) conditions and fast radiative decay. In the former case we find that the effective dynamics is described by classical rate equations up to second order in an appropriate perturbative expansion. This drastically reduces the computational complexity of numerical simulations in comparison to the full quantum master equation. When accounting for the fourth order correction in this expansion, however, we find that the resulting equation breaks the preservation of positivity and thus cannot be interpreted as a proper classical master rate equation. In the EIT system we find that the expansion up to second order retains information not only on the "classical" observables, but also on some quantum coherences. Nevertheless, this perturbative treatment still achieves a non-trivial reduction of complexity with respect to the original problem
Is the meiofauna a good indicator for climate change and anthropogenic impacts?
Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research
Is the meiofauna a good indicator for climate change and anthropogenic impacts?
Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research
Airborne Validation Results Part A
This document reports the results of the A-SMGCS airborne validation activities carried out in EMMA2 WP6.6 by the green team (DLR, TUD, FAV, and DAS). Different test campaigns took place:
Real time simulations (RTS) in June, July and October 2008.
Prague Airport on-site trials (OST) in August and November 2008.
During the airborne validation trials the following EMMA2 higher A-SMGCS components were implemented in different platforms and under evaluation: Ground Traffic Display (GTD); Ground Air Data Base Upload; Surface Movement Alerting (SMA); Traffic Conflict Detection (TCD) (fed by TIS-B); TAXI-CPDLC.
They were operated in different trials in total by twenty different pilots
Symptoms analysis of 3D TV viewing based on Simulator Sickness Questionnaires
Stereoscopic 3D TV viewing puts different visual demands on the viewer compared to 2D TV viewing. Previous research has reported on viewers' fatigue and discomfort and other negative effects. This study is to investigate further how severe and what symptoms may arise from somewhat longish 3D TV viewing. The MPEG 3DV project is working on the next-generation video encoding standard and in this process, MPEG issued a call for proposal of encoding algorithms. To evaluate these algorithms a large scale subjective test was performed involving Laboratories all over the world[1, 2]. For the participating Labs, it was optional to administer a slightly modified Simulator Sickness Questionnaire (SSQ) before and after the test. One of the SSQ data sets described in this article is coming from this study. The SSQ data from the MPEG test is the largest data set in this study and also contains the longest viewing times. Along with the SSQ data from the MPEG test, we have also collected questionnaire data in three other 3D TV studies. We did two on the same 3D TV (passive film pattern retarder) as in the MPEG test, and one was using a projector system. As comparison SSQ data from a 2D video quality experiment is also presented. This investigation shows a statistically significant increase in symptoms after viewing 3D TV primarily related to the visual or Oculomotor system. Surprisingly, 3D video viewing using projectors did not show this effect.First Online: 08 December 2016</p
Microbiology and antibiotics after second-stage revision of periprosthetic joint infections: A two-year follow-up cohort
International audienceBackground: Optimal duration of antimicrobial regimen after reimplantation of two-stage procedures for periprosthetic joint infection (PJI) is poorly standardized. The aim of this study was to assess the characteristics of reimplantation microbiology with 6 weeks (2nd stage positive culture) or 10 days (2nd stage negative culture) of antibiotics in patients with complex chronic PJI and factors associated with microbiology at reimplantation. Patients and methods: We performed a retrospective single-center study including all consecutive complex PJI recipients managed by two-stage surgery in a referral centre, from 2015 to 2018. Outcome was assessed at a minimum 2-year follow-up. Logistic regression analysis was performed to assess predictors of reimplantation microbiology. Results: Fifty patients (median age 69 [62–77] years) were included. PJI predominantly involved the hip (48%). The most common microorganisms were Staphylococcus aureus (36%), and coagulase-negative staphylococci (24%). At the second stage, reimplantation microbiology was positive for 10 patients (20%). Documentation was obtained within 48 hours. With median follow-up of 41 [30–50] months after reimplantation, treatment failure occurred in 4 patients (8%). Using log-rank to compare Kaplan–Meier survival curves, no difference in the probability of treatment failure was found according to reimplantation microbiology (P = 0.34). After adjustment, relapse was not associated with positive reimplantation microbiology (P = 0.53). Conclusions: In this work, positive microbiology at reimplantation did not predict treatment failure. Rapid growth at post-reimplantation suggests that antibiotic use should not exceed 10 days when cultures are negative. Additional studies are needed to determine the optimal duration of antibiotic therapy in case of negative microbiology. © 2022 Elsevier Masson SA
Active tactile exploration for adaptive locomotion in the stick insect
Schütz C, Dürr V. Active tactile exploration for adaptive locomotion in the stick insect. Phil.Trans.R.Soc.Lond. B. 2011;366(1581):2996-3005.Insects carry a pair of actively moveable feelers that supply the animal with a range of multimodal information. The antennae of the stick insect Carausius morosus are straight and of nearly the same length as the legs, making them ideal probes for near-range exploration. Indeed, stick insects, like many other insects, use antennal contact information for the adaptive control of locomotion, for example in climbing. Moreover, the active exploratory movement pattern of the antennae is context-dependent. The first objective of the present study is to reveal the significance of antennal contact information for the efficient initiation of climbing. This is done by means of kinematic analysis of freely walking animals as they undergo a tactually elicited transition from walking to climbing. The main findings are that fast, tactually elicited re-targeting movements may occur during an ongoing swing movement, and that the height of the last antennal contact prior to leg contact largely predicts the height of the first leg contact. The second objective is to understand the context-dependent adaptation of the antennal movement pattern in response to tactile contact. We show that the cycle frequency of both antennal joints increases after obstacle contact. Furthermore, inter-joint coupling switches distinctly upon tactile contact, revealing a simple mechanism for context-dependent adaptation
Mapping of a congenital microcoria locus to 13q31-q32.
Congenital microcoria is an autosomal dominant disorder characterized by a pupil with a diameter <2 mm. It is thought to be due to a maldevelopment of the dilator pupillae muscle of the iris, and it is associated with juvenile-onset glaucoma. A total genome search for the location of the congenital microcoria gene was launched in a single large family. We found linkage between the disease and markers located on 13q31-q32 (Zmax = 9.79; theta = 0). Haplotype analysis narrowed the linked region to an interval <8 cM between markers D13S1239 proximally and D13S1280 distally
Aperçu de la R&D CEA sur gaine du combustible base zirconium revêtue au chrome, pour résistance accrue en conditions accidentelles (APRP).
International audienc
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