6,821 research outputs found
Seismic monitoring of gas emissions at mud volcanoes: The case of Nirano (northern Italy)
Seismic signals generated at the Nirano mud volcanoes in Northern Italy have been monitored by deploying a set of small dimensions seismic arrays of vertical geophones and thee-directional sensors. During two seismic surveys campaigns, seismic signals characterized by sequences of short impulsive signals (lasting 0.1 s–0.2 s) were identified above the background seismic noise. The respective seismic sources have been identified at shallow depths (<30 m) and results sparsely distributed over a wide area. Estimated propagation velocities and polarization analysis indicate that detected pulses also include a significant S waves contribution. These findings have been interpreted as the effect of a stick-slip mechanism due to the interaction between exsolved gas bubbles, mud plugs and the vent walls. On the basis of this model, an estimate of the gas outflow was attempted and results in line with independent measurements of CH4 and CO2 emissions carried out in the area
A Survey on the Path Computation Element (PCE) Architecture
Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multi-domain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits
Fully superconducting josephson bolometers for gigahertz astronomy
The origin and the evolution of the universe are concealed in the evanescent diffuse extragalactic background radiation (DEBRA). To reveal these signals, the development of innovative ultra-sensitive bolometers operating in the gigahertz band is required. Here, we review the design and experimental realization of two bias-current-tunable sensors based on one dimensional fully superconducting Josephson junctions: the nanoscale transition edge sensor (nano-TES) and the Josephson escape sensor (JES). In particular, we cover the theoretical basis of the sensors operation, the device fabrication, their experimental electronic and thermal characterization and the deduced detection performance. Indeed, the nano-TES promises a state-of-the-art noise equivalent power (NEP) of about 5 × 10−20 W/√Hz, while the JES active region is expected to show an unprecedented NEP of the order of 10−25 W/√Hz. Therefore, the nano-TES and JES are strong candidates to push radio astronomy to the next level
Interventions for improving clinical outcomes and health-related quality-of-life for people living with skeletal dysplasias: an evidence gap map
Purpose: Skeletal dysplasias are rare genetic disorders that are characterized by abnormal development of bone and cartilage. There are multiple medical and non-medical treatments for specific symptoms of skeletal dysplasias e.g. pain, as well as corrective surgical procedures to improve physical functioning. The aim of this paper was to develop an evidence-gap map of treatment options for skeletal dysplasias, and their impact on patient outcomes. Methods: We conducted an evidence-gap map to identify the available evidence on the impact of treatment options on people with skeletal dysplasias on clinical outcomes (such as increase in height), and dimensions of health-related quality of life. A structured search strategy was applied to five databases. Two reviewers independently assessed articles for inclusion in two stages: titles and abstracts (stage 1), and full text of studies retained at stage 2. Results: 58 studies fulfilled our inclusion criteria. The included studies covered 12 types of skeletal dysplasia that are non-lethal with severe limb deformities that could result in significant pain and numerous orthopaedic interventions. Most studies reported on the effect of surgical interventions (n = 40, 69%), followed by the effect of treatments on dimensions of health quality-of-life (n = 4, 6.8%) and psychosocial functioning (n = 8, 13.8%). Conclusion: Most studies reported on clinical outcomes from surgery for people living with Achondroplasia. Consequently, there are gaps in the literature on the full range of treatment options (including no active treatment), outcomes and the lived experience of people living with other skeletal dysplasias. More research is warranted to examine the impact of treatments on health-related quality-of-life of people living with skeletal dysplasias, including their relatives to enable them to make preference- and valued based decisions about treatment
APE Results of Hadron Masses in Full QCD Simulations
We present numerical results obtained in full QCD with 2 flavors of Wilson
fermions. We discuss the relation between the phase of Polyakov loops and the
{\bf sea} quarks boundary conditions. We report preliminary results about the
HMC autocorrelation of the hadronic masses, on a lattice
volume, at with .Comment: 3 pages, compressed ps-file (uufiles), Contribution to Lattice 9
Hopf algebraic structure of the parabosonic and parafermionic algebras and paraparticle generalization of the Jordan Schwinger map
The aim of this paper is to show that there is a Hopf structure of the
parabosonic and parafermionic algebras and this Hopf structure can generate the
well known Hopf algebraic structure of the Lie algebras, through a realization
of Lie algebras using the parabosonic (and parafermionic) extension of the
Jordan Schwinger map. The differences between the Hopf algebraic and the graded
Hopf superalgebraic structure on the parabosonic algebra are discussed.Comment: 11 pages, LaTex2e fil
Self-selection effects in smokers attending lung cancer screening: a 9.5-year population-based cohort study in Varese, Italy.
BACKGROUND:: We hypothesize that mortality risk profile of participants and nonparticipants in nonrandomized lung cancer (LC) screening of smokers may be different. METHODS:: In 1997, a population-based cohort of 5815 smokers of Varese Province was invited to nonrandomized LC screening by annual chest x-ray examination for 4 years. LC risk factors and screening participation rate were recorded. Except for screening, the whole cohort received usual care. After 9.5-year observation, we compared mortality of participants versus nonparticipants by assessing age-standardized all-cause mortality rate ratio (MRR) and disease group-specific MRR with 95% confidence intervals (95% CI). RESULTS:: Self-selected screening participants were 21% of cohort. Participants were younger (p < 0.001), were more frequently current smokers (p = 0.019), had more pack-years of smoking (p < 0.0001), and had higher rate of LC family history (p < 0.0001) and of occupational LC risk (p < 0.0001) relative to nonparticipants. In logistic regression analysis familial LC, occupational risk and pack-years smoked were significant predictors of participation in screening and of developing LC. Participants displayed a healthy effect, as shown by all-cause MRR = 0.67 (95% CI, 0.53-0.84), all cancers except LC MRR = 0.61 (95% CI, 0.41-0.91), cardiovascular diseases MRR = 0.38 (95% CI, 0.22-0.63), and noncancer disease other than cardiovascular or respiratory MRR = 0.57 (95% CI, 0.34-0.92). The LC mortality (MRR = 1.40; 95% CI, 1.03-1.91) was higher in participants relative to nonparticipants (p = 0.031). CONCLUSION:: The selection effect in LC screening participants was dual: healthy effect and higher LC mortality. In assessing the overall effectiveness of LC screening on a population level, a higher LC mortality risk in participants should be considered
Decay Constants of Heavy-Light Mesons
The decay constants of the heavy-light pseudoscalar mesons are studied in a
high statistics run using the Wilson action at and , and
the clover action at . The systematics of discretisation
errors are discussed. Our best estimates of the decay constants are: =
218(9) MeV, = 1.11(1) and we obtain preliminary values for .Comment: at the Dallas Lattice Conference, October 1993. 3 pages in a single
postscript file, uuencoded form. Rome Preprint 93/98
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