2,347 research outputs found
Telecommunication Economics - Overview of the Field, Recommendations, and Perspectives
Telecommunication economics has evolved into an area of research, which includes technical aspects, social issues, economic and business factors, and regulation demands. The combination of those four dimensions is becoming critical for a suitable and viable understanding of communication needs in today's society. Therefore, this report on the Dagstuhl Perspectives Seminar ‘‘Telecommunication Economics''summarizes a number of key aspects of this field, it develops a set of selected and detailed recommendations, and outlines respective perspectives, which are being worked on partially already today and which need a much closer attention in the mid-term futur
The Ontogeny of Escape Responses and Locomotor Performance in Sceloporus Woodi
Predator prey interactions have the potential to shape patterns of natural selection. For prey, avoiding detection by predators is of primary importance; however prey species risk detection by movement. Other than crypsis, prey species also use secondary defenses when detected by a predator. The most common secondary defense is flight. Flight initiation distance describes the distance between a prey item and a predator where the benefits of fleeing outweigh the benefits of remaining stationary. There are many factors that influence flight initiation distance including ontogenetic stage, ability to escape, and the degree of crypsis. Of these, the ontogenetic effects on escape velocity and flight initiation distance are likely to be substantial. Juvenile and hatchling animals typically have a lower absolute velocity than adults. If escape velocity is a key variable in survival, then juveniles may be forced to tolerate shorter flight initiation distances than adults. As a result, they may switch anti-predator tactics or be susceptible to higher predation risk than adults. Hence, flight initiation distance of juveniles may be optimized such that their decreased locomotor abilities and use of immobility for concealment changes at a particular body size. I examined this hypothesis in Sceloporus woodi, a small terrestrial lizard. Field measurements of escape velocity were recorded on an ontogenetic series of lizards using high speed video. Maximal running velocity was also quantified on a laboratory raceway to examine if the velocities used by lizards in the field are reflective of maximal velocities as measured in the lab, or if other variables, such as muscle size and limb size, are correlated with flight initiation distance and running performance. I found that hind limb morphology scales isometrically with body size. Maximum velocity in the lab increased with size, adults being fastest and hatchlings being slowest (F2, 97 = 12.6088, P = \u3c0.0001). Escape velocity in the field did not vary between adults, juveniles, and hatchlings (F2, 24 = 2.39, P = 0.114). Flight initiation distance increased as body size increased (F2, 39 = 3.32, P = 0.047). Larger animals did not allow close approach of a human predator presumably escaping early and to avoid the need to use high sprint velocities to escape. Smaller lizards, due to slower sprint velocities, must use behavior to compensate for decreased sprint velocity. Small lizards remained immobile longer, allowing close approach of the predator, likely relying on crypsis to remain concealed. By remaining immobile longer, smaller lizards did not attract unnecessary attention of the predator and likely increase the probability of being required to use sprinting to escape predation. Isometric scaling coupled with the findings for sprint and escape velocity allow all classes to perform similarly thus optimizing hatchling and juvenile survival
Report on the 2nd International Summer School on Network and Service Management (ISSNSM'08)
This report summarizes the 2nd International Summer School on Network and Service Management (ISSNSM'08), which was held at the Communication Systems Group (CSG) of the Department of Informatics (IFI), University of Zurich, Switzerland, on 2-6 June 2008. Supported by the European FP6 Network of Excellence for the Management of Internet Technologies and Complex Services (EMANICS), the ISSNSM presented within 5 days eight different topics, covering the areas of (1) security, (2) virtualization and simulations, and (3) network monitoring and management. All of these run for a full or half day, including a short theoretical introduction and larger practical lab course components, respectivel
A prototype and demonstrator of Akogrimo’s architecture: An approach of merging grids, SOA, and the mobile Internet
The trend of merging telecommunication infrastructures with traditional Information Technology (IT) infrastructures is ongoing and important for commercial service providers. The driver behind this development is, on one hand, the strong need for enhanced services and on the other hand, the need of telecommunication operators aiming at value-added service provisioning to a wide variety of customers. In the telecommunications sector, the IP Multimedia Subsystem (IMS) is a promising service platform, which may become a ''standard'' for supporting added-value services on top of the next generation network infrastructure. However, since its range of applicability is bound to SIP- enabled services, IMS extensions are being proposed by ''SIPifying'' applications. In parallel to these developments within the traditional IT sector, the notion of Virtual Organizations (VO) enabling collaborative businesses across organizational boundaries is addressed in the framework of Web Services (WS) standards implementing a Service-oriented Architecture (SOA). Here, concepts for controlled resource and service sharing based on WS and Semantic Technologies have been consolidated. Since the telecommunications sector has become, in the meantime ''mobile'', all concepts brought into this infrastructure must cope with the dynamics mobility brings in. Therefore, within the Akogrimo project the VO concept has been extended towards a Mobile Dynamic Virtual Organization (MDVO) concept, additionally considering key requirements of mobile users and resources. Especial attention is given to ensure the duality of the merge of both, SOA and IMS approaches to holistically support SOA-enabled mobile added-value services and their users. This work describes major results of the Akogrimo project, paying special attention to the overall Akogrimo architecture, the prototype implemented, and the key scenario in which the instantiated Akogrimo architecture shows a very clear picture of applicability, use, and an additional functional evaluation
Nitrogen compounds and ozone in the stratosphere: comparison of MIPAS satellite data with the Chemistry Climate Model ECHAM5/MESSy1
International audienceThe chemistry climate model ECHAM5/MESSy1 (E5/M1) in a setup extending from the surface to 80 km with a vertical resolution of about 600 m near the tropopause with nudged tropospheric meteorology allows a direct comparison with satellite data of chemical species at the same time and location. Here we present results out of a transient 10 years simulation for the period of the Antarctic vortex split in September 2002, where data of MIPAS on the ENVISAT-satellite are available. For the first time this satellite instrument opens the opportunity, to evaluate all stratospheric nitrogen containing species simultaneously with a good global coverage, including the source gas N2O which allows an estimate for NOx-production in the stratosphere. We show correlations between simulated and observed species in the altitude region between 10 and 50 hpa for different latitude belts, together with the Probability Density Functions (PDFs) of model results and observations. This is supplemented by global charts on pressure levels showing the satellite data and the simulated data sampled at the same time and location. We demonstrate that the model in most cases captures the partitioning in the nitrogen family, the diurnal cycles and the spatial distribution within experimental uncertainty. There appears to be, however, a problem to reproduce the observed nighttime partitioning between N2O5 and NO2 in the middle stratosphere
Quantum coherent control in pulsed waveguide optomechanics
Coherent control of traveling acoustic excitations in a waveguide system is an interesting way to manipulate and transduce classical and quantum information. So far, these interactions, often based on optomechanical resonators or Brillouin scattering, have been studied in the steady-state regime using continuous waves. However, waveguide experiments are often based on optical pump pulses, which require treatment in a dynamic framework. In this paper, we present an effective Hamiltonian formalism in the dynamic regime using optical pulses that links waveguide optomechanics and cavity optomechanics, which can be used in the classical and quantum regime including quantum noise. Based on our formalism, a closed solution for coupled-mode equation under the undepleted assumption is provided and we found that the strong coupling regime is already accessible in current Brillouin waveguides by using pulses. We further investigate several possible experiments within waveguide optomechanics, including Brillouin-based coherent transfer, Brillouin cooling, and optoacoustic entanglement
Myeloperoxidase and eosinophil cationic protein in serum and sputum during antibiotic treatment in cystic fibrosis patients with Pseudomonas aeruginosa infection
I order to study the time-course of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) as parameters for monitoring inflammation in cystic fibrosis (CF), we investigated ten patients during both a 14-day intravenous antibiotic treatment and a corresponding self control. Modified Shwachman-Kulczycki score improved significantly (p < 0.008), C-reactive protein (CRP) levels decreased significantly (p < 0.05) during antibiotic treatment, while in the control phase there were no significant differences. Lung function parameters did not change significantly during antibiotic treatment or control phase. Serum MPO concentration (p < 0.006) and peripheral blood neutrophil granulocyte counts (p < 0.04) decreased significantly during antibiotic treatment, but not during the control phase. Sentm ECP concentration showed a tendency to decrease during antibiotic treatment, but this failed to reach significance. In general, sputum concentrations of MPO and ECP Were 500- to 1000-fold higher than in serum. However, neither MPO nor ECP in sputum showed a significan variation over time during antibiotic treatment or control phase. From our data we conclude that: (1) measurements of MPO, neutrophils and CRP in peripheral blood do correlate with clinical parameters such as the modified Shwachman-Kulczycki score; (2) neutrophils and MPO seem to reflect inflammatory changes induced by antibiotic treatment; (3) eosinophils may play a role in CF by an enhanced ‘releasability’ and (4) Sputum measurements of mediators of inflammation cannot be recommended
New actors and new strategies after NPM reforms: coping with a trust crisis in collective bargaining across nine EU member states
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