167 research outputs found
Performance Evaluation of the Labelled OBS Architecture
A comparison of three different Optical Burst Switching (OBS) architectures
is made, in terms of performance criteria, control and hardware complexity,
fairness, resource utilization, and burst loss probability. Regarding burst
losses, we distinguish the losses due to burst contentions from those due to
contentions of Burst Control Packets (BCP). The simulation results show that as
a counterpart of an its additional hardware complexity, the labelled OBS
(L-OBS) is an efficient OBS architecture compared to a Conventional OBS (C-OBS)
as well as in comparison with Offset Time-Emulated OBS (E-OBS)
A survey of the transmission of infectious diseases/infections between wild and domestic ungulates in Europe
The domestic animals/wildlife interface is becoming a global issue of growing interest. However, despite studies on wildlife diseases being in expansion, the epidemiological role of wild animals in the transmission of infectious diseases remains unclear most of the time. Multiple diseases affecting livestock have already been identified in wildlife, especially in wild ungulates. The first objective of this paper was to establish a list of infections already reported in European wild ungulates. For each disease/infection, three additional materials develop examples already published, specifying the epidemiological role of the species as assigned by the authors. Furthermore, risk factors associated with interactions between wild and domestic animals and regarding emerging infectious diseases are summarized. Finally, the wildlife surveillance measures implemented in different European countries are presented. New research areas are proposed in order to provide efficient tools to prevent the transmission of diseases between wild ungulates and livestock
Optical Power Control to Efficiently Handle Flex-Grid Spectrum Gain over Existing Fixed-Grid Network Infrastructures
International audienceThe exponential traffic growth in optical networks has triggered the evolution from Fixed-Grid to Flex-Grid technology. This evolution allows better spectral efficiency and spectrum usage over current networks in order to facilitate dynamic and huge traffic demands. The integration of Flex-Grid technology increases the number of optical channels established over optical links, leading, however, to an increase in amplification power and possibly saturating optical amplifiers. In this work, we propose a power adaptation process that takes advantage of link optical signal to noise ratio (OSNR) margins to allow network operators to support this power increase while maintaining the use of legacy amplifiers. Results show that controlling channel optical power benefits from the Flex-Grid in terms of spectrum and capacity gain using in-place amplifier infrastructure
Is the black grouse (Lyrurus tetrix) an indirect victim of the sylvatic rabies eradication by fox vaccination?
peer reviewedINTRODUCTION
Since 2017, a reinforcement program was developed to save the last, endangered, Belgian
population of black grouse (Lyrurus tetrix), in the High Fens Natural Park. To improve the success of this program, an analysis of past data of this population was undertaken to understand the causes of its past decline. Climate models, applied in previous studies to explain these population trends in the High Fens, failed to describe this major modification in this population’s dynamic and its recent decline.
MATERIAL AND METHODS
A time series analysis was applied on the core population to understand the causes of its past decline, using annual spring male census data recorded between 1967 and 2016.
RESULTS AND DISCUSSION
In the period 1967–1993, there was a fluctuation around an equilibrium of a population of ca. 40–45 males. After 1993, the population dynamic changed drastically, decreasing continuously until finally reaching quasi-extinction. On average, the population lost 15.4% of its size each year. Red fox (Vulpes vulpes) populations in Western Europe experienced a significant decline and stabilized at lower densities than observed in the past due to an outbreak of sylvatic rabies. In early 1990s, a fox demographic explosion followed a massive vaccination campaign, and fox populations became larger than had been observed before the epizootic. The eradication of the rabies was not the direct cause of this demographic explosion, as rabies-free areas experienced it also (but earlier). The causes are more to be sought in environmental modifications induced by humans.
CONCLUSIONS
Around 1993, the remarkable synchronicity between the beginning of the Black Grouse
population decline in High Fens and the fox demographic explosion suggests a significant increase in predation on this bird species. If the fox is singled out for this change in Black grouse dynamics, it should not be concluded that it is entirely responsible for this decline. It is quite possible that other factors have added up, such as the arrival or increase of other predators (the raccoon in particular, but also the wild boar, and better health of the populations of large raptors), deer overgrazing, and other subtle habitat changes and in climate
On the Legacy Amplifier Limitation in Flexgrid Optical Networks
International audienceFlexgrid technology is an interesting solution to improve network capacity. However, for a given spectral band, it gives rise to the increase of the number of channels, requiring more amplification power in respect with the conventional fixed grid technology. In this work, we demonstrate that re-engineering the link margins allows supporting this increase while keeping in use legacy amplifier
Link Design and Legacy Amplifier Limitation in Flex-grid Optical Networks
International audienceFlex-grid technology is an effective mean to improve the spectral efficiency of optical communications. For a given amplifier spectral bandwidth, it gives rise to the increase of the number of optical channels as it reduces the channel spacing. Therefore, in order to reap full benefits from flex-grid saved spectrum, further amplification power is required with respect to conventional fixed grid. This is a strong limitation if the legacy amplifiers cannot meet this new requirement due to their optical power limits. In this work, we demonstrate that exploiting the link margins allows supporting this increase while maintaining in use legacy amplifiers
Réalisation d’un Contrat d’Etudes Prospectives des secteurs du transport: Rapport final
Le CEP a pour objectif de réaliser un état des lieux du secteur, de conduire une analyse prospective qualitative et quantitative de l’évolution des métiers et des besoins de compétences du transport et de préconiser un plan d’actions pour les transports routiers, maritimes et fluviaux. A l’issue des travaux d’étude, le rapport final a été remis aux membres du Comité de pilotage (Ministère de l’emploi - DGEFP, Représentants des branches des transports, l’OPCA Transports et Services, Pôle Emploi, Ministère de l’écologie et du développement durable, des transport et du logement)
A New Highly Conserved Antibiotic Sensing/Resistance Pathway in Firmicutes Involves an ABC Transporter Interplaying with a Signal Transduction System
Signal transduction systems and ABC transporters often contribute jointly to adaptive bacterial responses to environmental changes. In Bacillus subtilis, three such pairs are involved in responses to antibiotics: BceRSAB, YvcPQRS and YxdJKLM. They are characterized by a histidine kinase belonging to the intramembrane sensing kinase family and by a translocator possessing an unusually large extracytoplasmic loop. It was established here using a phylogenomic approach that systems of this kind are specific but widespread in Firmicutes, where they originated. The present phylogenetic analyses brought to light a highly dynamic evolutionary history involving numerous horizontal gene transfers, duplications and lost events, leading to a great variety of Bce-like repertories in members of this bacterial phylum. Based on these phylogenetic analyses, it was proposed to subdivide the Bce-like modules into six well-defined subfamilies. Functional studies were performed on members of subfamily IV comprising BceRSAB from B. subtilis, the expression of which was found to require the signal transduction system as well as the ABC transporter itself. The present results suggest, for the members of this subfamily, the occurrence of interactions between one component of each partner, the kinase and the corresponding translocator. At functional and/or structural levels, bacitracin dependent expression of bceAB and bacitracin resistance processes require the presence of the BceB translocator loop. Some other members of subfamily IV were also found to participate in bacitracin resistance processes. Taken together our study suggests that this regulatory mechanism might constitute an important common antibiotic resistance mechanism in Firmicutes. [Supplemental material is available online at http://www.genome.org.
Skeletal Muscle Biopsy Analysis in Reducing Body Myopathy and Other Fhl1-related Disorders
FHL1 mutations have been associated with various disorders that include reducing body myopathy (RBM), Emery-Dreifuss-like muscular dystrophy, isolated hypertrophic cardiomyopathy, and some overlapping conditions. We report a detailed histochemical, immunohistochemical, electron microscopic, and immunoelectron microscopic analyses of muscle biopsies from 18 patients carrying mutations in FHL1: 14 RBM patients (Group 1), 3 Emery-Dreifuss muscular dystrophy patients (Group 2), and 1 patient with hypertrophic cardiomyopathy and muscular hypertrophy (Group 2). Group 1 muscle biopsies consistently showed RBs associated with cytoplasmic bodies. The RBs showed prominent FHL1 immunoreactivity whereas desmin, alpha B-crystallin, and myotilin immunoreactivity surrounded RBs. By electron microscopy, RBs were composed of electron-dense tubulofilamentous material that seemed to spread progressively between the myofibrils and around myonuclei. By immunoelectron microscopy, FHL1 protein was found exclusively inside RBs. Group 2 biopsies showed mild dystrophic abnormalities without RBs; only minor nonspecific myofibrillar abnormalities were observed under electron microscopy. Molecular analysis revealed missense mutations in the second FHL1 LIM domain in Group 1 patients and ins/del or missense mutations within the fourth FHL1 LIM domain in Group 2 patients. Our findings expand the morphologic features of RBM, clearly demonstrate the localization of FHL1 in RBs, and further illustrate major morphologic differences among different FHL1-related myopathies
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