Representing anisotropic subduction zones with isotropic velocity models: A characterization of the problem and some steps on a possible path forward

Despite the widely known fact that mantle flow in and around subduction zones produces the development of considerable seismic anisotropy, most P-wave tomography efforts still rely on the assumption of isotropy. In this study, we explore the potential effects of erroneous assumption on tomographic images and explore an alternative approach. We conduct a series of synthetic tomography tests based on a geodynamic simulation of subduction and rollback. The simulation results provide a self-consistent distribution of isotropic (thermal) anomalies and seismic anisotropy which we use to calculate synthetic delay times for a number of realistic and hypothetical event distributions. We find that anisotropy-induced artifacts are abundant and significant for teleseismic, local and mixed event distributions. The occurrence of artifacts is not reduced, and indeed can be exacerbated, by increasing richness in ray-path azimuths and incidence angles. The artifacts that we observe are, in all cases, important enough to significantly impact the interpretation of the images. We test an approach based on prescribing the anisotropy field as an a priori constraint and find that even coarse approximations to the true anisotropy field produce useful results. Using approximate anisotropy, fields can result in reduced RMS misfit to the travel time delays and reduced abundance and severity of imaging artifacts. We propose that the use of anisotropy fields derived from geodynamic modeling and constrained by seismic observables may constitute a viable alternative to isotropic tomography that does not require the inversion for anisotropy parameters in each node of the model

Waterborne GPR survey for estimating bottom-sediment variability: A survey on the Po River, Turin, Italy

We conducted an integrated geophysical survey on a stretch of the river Po in order to check the GPR ability to discriminate the variability of riverbed sediments through an analysis of the bottom reflection amplitudes. We conducted continuous profiles with a 200-MHzGPR system and a handheld broadband EM sensor.Aconductivity meter and a TDR provided punctual measurements of water conductivity, permittivity, and temperature. The processing and interpretation of the GEM-2 and GPR data were enhanced by reciprocal results and by integration with the punctual measurements of the EM properties of the water. We used a processing flow that improved the radargram images and preserved the amplitude ratios among the different profiles and the frequency content at the bottom reflection signal.We derived the water attenuation coefficient both from the punctual measurements using the Maxwell formulas and from the interpretation of the GPR data, finding an optimal matching between the two values. The GPR measurements provided maps of the bathymetry and of the bottom reflection amplitude. The high reflectivity of the riverbed, derived from the GPR interpretation, agreed with the results of the direct sampling campaign that followed the geophysical survey. The variability of the bottom-reflection-amplitudes map, which was not confirmed by the direct sampling, could also have been caused by scattering phenomena due to the riverbed clasts which are dimensionally comparable to the wavelength of the radar pulse

Estudio de laboratorio de la susceptibilidad a la corrosión intergranular del cinc y su relación con el contenido de aluminio

A method of test for determining the susceptibility of zinc to the intergranular corrosion was developped, considering that the action of water steam on zinc produces the mentioned type of corrosion. Local and foreing specimens have been studied. In the suscep- tibies specimens, the sign of intergranular corrosion, characterized by visual and micrographic observations, appears after 30 h exposition. Correlation between susceptibility and aluminium content was established: 0,005 $ of aluminium in laminated zinc was the maximum content in order to avoid corrosion.Se ideó un método de ensayo para, determinar la susceptibilidad del cinc a la corrosión intergranular, teniendo en cuenta que el ataque con vapor de agua provoca en el cinc ese tipo corrosión. Se ensayaron probetas de origen nacional y extranjero. En las muestras susceptibles,los signos, de corrosión intergranular — que fueron caracterizados mediante observaciones visuales y micrográficas -r aparecieron después de las 30, horas de exposición. Se estableció una correlación entre esa susceptibilidad y él contenido de aluminio, y se fijó como contenido máximo de aluminio en -cinc laminado el de 0,005 %

Symmetric Periodic Solutions of the Anisotropic Manev Problem

We consider the Manev Potential in an anisotropic space, i.e., such that the force acts differently in each direction. Using a generalization of the Poincare' continuation method we study the existence of periodic solutions for weak anisotropy. In particular we find that the symmetric periodic orbits of the Manev system are perturbed to periodic orbits in the anisotropic problem.Comment: Late

Cloud-based robots and intelligent space teleoperation tools

Despite an idea of robotic system teleoperation is a relatively old concept, here we present its enhancements heading to an interconnection of teleoperation and collecting relevant information from the environment where robots act. This environment should be an intelligent space featured with various devices and sensors, which allows to obtain, preprocess and stores data in the cloud. Those data should provide relevant information for teleoperator or directly for robots, which act autonomously. For this purpose, we developed cloud-based tools, named Telescope v2. It is a platform-independent system for remote monitoring and controlling various systems. In this paper, we introduce this system, its abilities, and compare it with its network-based ancestor, Telescope v1. We analyze measurements of latency and response time when our new system is used for teleoperation in different places equipped with various Internet bandwidths

Observation of confinement-induced resonances in a 3D lattice

We report on the observation of confinement-induced resonances for strong three-dimensional (3D) confinement in a lattice potential. Starting from a Mott-insulator state with predominantly single-site occupancy, we detect loss and heating features at specific values for the confinement length and the 3D scattering length. Two independent models, based on the coupling between the center-of-mass and the relative motion of the particles as mediated by the lattice, predict the resonance positions to a good approximation, suggesting a universal behavior. Our results extend confinement-induced resonances to any dimensionality and open up an alternative method for interaction tuning and controlled molecule formation under strong 3D confinement.Comment: 9 pages, 5 figure

Decision focused inference on networked probabilistic systems : with applications to food security

Bayesian technologies have been progressively applied to larger and larger domains. Here necessarily probability judgments are made collaboratively and it is rare that one agent owns all probability judgments in the system. So interesting new foundational and methodological issues have arisen associated with the status of inference support by combinations of such judgments. In this paper we review some recent work on Bayesian inference underlying integrated decision support for huge processes. We argue that in a surprising number of such dynamic environments it is in fact formally justified to distribute the inference between different panels of experts and then use an agreed framework to knit these separate judgments to properly score different policies. We also briefly report recent progress in applying this new technology to develop an integrating decision support system for local government officials to use when trying to evaluate implications on food poverty of shocks in the food supply chain if various ameliorating policies are applied