Physical parameters in the hot spots and jets of Compact Symmetric Objects

We present a model to determine the physical parameters of jets and hot spots of a sample of CSOs under very basic assumptions like synchrotron emission and minimum energy conditions. Based on this model we propose a simple evolutionary scenario for these sources assuming that they evolve in ram pressure equilibrium with the external medium and constant jet power. The parameters of our model are constrained from fits of observational data (radio luminosity, hot spot radius and hot spot advance speed) versus projected linear size. From these plots we conclude that CSOs evolve self-similarly and that their radio luminosity increases with linear size along the first kiloparsec. Assuming that the jets feeding CSOs are relativistic from both kinematical and thermodynamical points of view, we use the values of the pressure and particle number density within the hot spots to estimate the fluxes of momentum (thrust), energy, and particles of these relativistic jets. The mean jet power obtained in this way is within an order of magnitude that inferred for FRII sources, which is consistent with CSOs being the possible precursors of large doubles. The inferred flux of particles corresponds to, for a barionic jet, about a 10% of the mass accreted by a black hole of $10^8 {\rm M_{\odot}}$ at the Eddington limit, pointing towards a very efficient conversion of accretion flow into ejection, or to a leptonic composition of jets.Comment: 11 pages, 2 figures. Accepted for publication in Astrophysical Journa

The Role of Fermions in Bubble Nucleation

We present a study of the role of fermions in the decay of metastable states of a scalar field via bubble nucleation. We analyze both one and three-dimensional systems by using a gradient expansion for the calculation of the fermionic determinant. The results of the one-dimensional case are compared to the exact results of previous work.Comment: 15 pages, revtex, 9 figure

A Search for Molecular Gas in GHz Peaked Spectrum Radio Sources

We present searches for molecular gas (CO, OH, CS, and Ammonia) in six GHz Peaked Spectrum (GPS) radio sources. We do not detect gas in any source and place upper limits on the mass of molecular gas which are generally in the range 1E9 to a few times 1E10 solar masses. These limits are consistent with the following interpretations: (1) GPS sources do not require very dense gas in their hosts, and (2) The GPS sources are unlikely to be confined by dense gas and will evolve to become larger radio sources

Developing a site-conditions map for seismic hazard Assessment in Portugal

The evaluation of site effects on a broad scale is a critical issue for seismic hazard and risk assessment, land use planning and emergency planning. As characterization of site conditions based on the shear-wave velocity has become increasingly important, several methods have been proposed in the literature to estimate its average over the first thirty meters (Vs30) from more extensively available data. These methods include correlations with geologic-geographic defined units and topographic slope. In this paper we present the first steps towards the development of a site–conditions map for Portugal, based on a regional database of shear-wave velocity data, together with geological, geographic, and lithological information. We computed Vs30 for each database site and classified it according to the corresponding geological-lithological information using maps at the smallest scale available (usually 1:50000). We evaluated the consistency of Vs30 values within generalized-geological classes, and assessed the performance of expedient methodologies proposed in the literature

A common garden design reveals population-specific variability in potential impacts of hybridisation between populations of farmed and wild Atlantic salmon, Salmo salar L

Released individuals can have negative impacts on native populations through various mechanisms; including competition, disease transfer and introduction of maladapted gene-complexes. Previous studies indicate that the level of farmed Atlantic salmon introgression in native populations is population-specific. However few studies have explored the potential role of population diversity or river characteristics, such as temperature, on the consequences of hybridisation. We compared freshwater growth of multiple families derived from two farmed, five wild, and two F1 hybrid salmon populations at three contrasting temperatures (7°C, 12°C, and 16°C) in a common garden experiment. As expected, farmed salmon outgrew wild salmon at all temperatures, with hybrids displaying intermediate growth. However, differences in growth were population-specific and some wild populations performed better than others relative to the hybrid and farmed populations at certain temperatures. Therefore, the competitive balance between farmed and wild salmon may depend both on the thermal profile of the river and the genetic characteristics of the respective farmed and wild strains. While limited to F1 hybridisation, the present study shows the merits in adopting a more complex spatially resolved approach to risk management of local populations

Occurrence and relative abundance of common\ud dolphins in three sites of the Portuguese shore

Throughout the years some researchers have dedicated their efforts to the study of cetaceans’\ud occurrence off Portugal mainland. However, it is still missing a systemic scientific methodology\ud for studying the presence of coastal small cetaceans. This work is a recent approach to the\ud occurrence and relative abundance estimative of cetaceans and especially common dolphins off\ud the west central coast of Portugal. Boat-based visual surveys were conducted in three different\ud geographic locations, resulting in the sighting of several species. In Nazaré we have only\ud observed Delphinus delphis while in Peniche and Sesimbra a great diversity of species was\ud recorded, including Tursiops truncatus, Stenella coeruleoalba, Phocoena phocoena and\ud Balaenoptera acutorostrata. Most frequently sighted was common dolphin (62%). Occurrence\ud of large groups of this species seems to take place along main ocean topographic features, like\ud the Portuguese submarine canyons and we consider that great depths near shore are suitable\ud habitats for more pelagic species of dolphins such as common dolphins. Total index of common\ud dolphin abundance was of 2.198 individuals per surveyed hour. A much smaller APUE was\ud found for Peniche than for the other two regions, where common dolphins show a similar\ud relative abundance. Future studies using linear transects and continuous long-term approaches\ud will give further insight to small cetaceans’ occurrence along Portugal mainland and its relation\ud with different oceanographic features, particularly depths and distances to shore. On-going\ud efforts in coming years added to this first approach will be required to obtain knowledge for the\ud conservation of cetaceans

Leveraging context-awareness to better support the IoT cloud-edge continuum

Novel Internet of Things (IoT) requirements derived from a broader interconnection of heterogeneous devices have pushed the horizons of Cloud computing and are giving rise to a wider decentralisation of applications and data centers. An answer to the underlying network concerns, such as the need to lower the resulting latency due to heavy computation needs, or safety aspects, gave rise to Edge/Fog computing, where IoT functionality can be also supported closer to data sources. While it is today feasible to perform some IoT functionality on the Edge, the orchestration of operations between Edge and Cloud requires an automated support, where context-awareness plays a key role in assisting the network in deciding when and where to store data and to perform computation. This work is focused on the application of context-awareness to support a smoother operation of the Edge to Cloud operation, aiming at lowering latency, in particular when real-time or close-to-real-time data exchange is present.info:eu-repo/semantics/publishedVersio

Dating COINS: Kinematic Ages for Compact Symmetric Objects

We present multi-epoch VLBA observations of Compact Symmetric Objects (CSOs) from the COINS sample (CSOs Observed In the Northern Sky). These observations allow us to make estimates of, or place limits on, the kinematic ages for those sources with well-identified hot spots. This study significantly increases the number of CSOs with well-determined ages or limits. The age distribution is found to be sharply peaked under 500 years, suggesting that many CSOs die young, or are episodic in nature, and very few survive to evolve into FR II sources like Cygnus A. Jet components are found to have higher velocities than hot spots which is consistent with their movement down cleared channels. We also report on the first detections of significant polarization in two CSOs, J0000+4054 (2.1%) and J1826+1831 (8.8%). In both cases the polarized emission is found in jet components on the stronger side of the center of activity.Comment: 34 pages including 7 figures, Accepted to ApJ on Dec 7, 200

Pulmonary Kaposi sarcoma and disseminated Mycobacterium genavense infection in an HIV-infected patient

We report a case of Kaposi sarcoma (KS) and disseminated infection by Mycobacterium genavense in a 40-year-old HIV-positive man with CD4+ T-cell count 5/µL. He presented with anorexia, diarrhoea, cachexia and multiple firm violaceous nodules distributed over the face, neck and upper and lower extremities. Biopsy of a skin nodule was performed, confirming KS. Immunoperoxidase staining for human herpesvirus 8 was strongly positive. Endoscopic examination revealed erosive duodenopathy. Multiple biopsy samples showed numerous acid-fast bacilli at direct microscopic examination. Real-time PCR (RT-PCR) identified M. genavense. A CT scan showed diffuse pulmonary infiltrates with a 'tree-in-bud' appearance, striking splenomegaly and abdominal lymphadenopathy. A bronchoscopy was performed, revealing typical Kaposi's lesions in the upper respiratory tract. RT-PCR of bronchial aspirate identified M. genavense and Pneumocystis jirovecii. Despite treatment with highly active antiretroviral therapy, antimycobacterial therapy and trimethoprim/sulfamethoxazole, the outcome was fatal