Phase rigidity breaking in open Aharonov-Bohm ring coupled to a cantilever

The conductance and the transmittance phase shifts of a two-terminal Aharonov-Bohm (AB) ring are analyzed in the presence of mechanical displacements due to coupling to an external can- tilever. We show that phase rigidity is broken, even in the linear response regime, by means of inelastic scattering due to phonons. Our device provides a way of observing continuous variation of the transmission phase through a two-terminal nano-electro-mechanical system (NEMS). We also propose measurements of phase shifts as a way to determine the strength of the electron-phonon coupling in NEMS.Comment: 7 pages, 8 figure

Effects of fission-fragment damage on vortex dimensionality in silver-sheathed Bi2Sr2Ca2Cu3Ox tapes

We report on the vortex dimensionality of uranium-doped Ag/Bi2223 tapes, before and after irradiation to a thermal-neutron fluence. The effective activation energies, as a function of current density and applied field, were calculated from dynamic magnetization relaxation measurements. A dimensional crossover from a three-dimensional (3D) elastic creep regime to a 2D plastic creep was observed in the nonirradiated tape at an applied magnetic field µ0Hcr[approximate]0.37 T, with an associated change in the flux hop velocity and temperature dependence. After the introduction of the fission-fragment damage by irradiation, a shift in the crossover to µ0Hcr[approximate]0.65 T was observed. These results indicate an enhancement of the c-axis vortex coherence by the introduced splayed columnar defects, explaining the greater pinning efficiency of the uranium-fission method in Bi2223 rather than the less anisotropic Y123. Conflicting results obtained for the irradiated tape in the absence of any temperature scaling of the activation energies demonstrate the importance of the inclusion of scaling in the magnetization relaxation analysis

Measuring GNSS ionospheric total electron content at Concordia, and application to L-band radiometers

In the framework of the project BIS - Bipolar Ionospheric Scintillation and Total Electron Content Monitoring, the ISACCO-DMC0 and ISACCO-DMC1 permanent monitoring stations were installed in 2008. The principal scope of the stations is to measure the ionospheric total electron content (TEC) and to monitor the ionospheric scintillations, using high-sampling-frequency global positioning system (GPS) ionospheric scintillation and TEC monitor (GISTM) receivers. The disturbances that the ionosphere can induce on the electromagnetic signals emitted by the Global Navigation Satellite System constellations are due to the presence of electron density anomalies in the ionosphere, which are particularly frequent at high latitudes, where the upper atmosphere is highly sensitive to perturbations coming from outer space. With the development of present and future low-frequency space-borne microwave missions (e.g., Soil Moisture and Ocean Salinity [SMOS], Aquarius, and Soil Moisture Active Passive missions), there is an increasing need to estimate the effects of the ionosphere on the propagation of electromagnetic waves that affects satellite measurements. As an example, how the TEC data collected at Concordia station are useful for the calibration of the European Space Agency SMOS data within the framework of an experiment promoted by the European Space Agency (known as DOMEX) will be discussed. The present report shows the ability of the GISTM station to monitor ionospheric scintillation and TEC, which indicates that only the use of continuous GPS measurements can provide accurate information on TEC variability, which is necessary for continuous calibration of satellite data

Synergic use of botulinum toxin injection and radial extracorporeal shockwave therapy in multiple sclerosis spasticity

Background and aim: In Multiple Sclerosis (MS) spasticity worsens the patient’s quality of life. Botulinum NeuroToxin TypeA (BoNT-A) is extensively used in focal spasticity, frequently combined with physical therapies. Radial extracorporeal shock waves (rESW) were already used in association with BoNTA. Considering that loss of efficacy and adverse events are determinants of BoNT-A treatment interruption, this study aimed to evaluate the possibility to prolong BoNT-A’s effect by using rESW in MS focal spasticity. Methods: Sixteen MS patients with spasticity of triceps surae muscles were first subjected to BoNT-A therapy and, four months later, to 4 sections of rESWT. Patients were evaluated before, 30, 90 days after the end of the treatments, by using Modified Ashworth Scale (MAS), Modified Tardieu Scale (MTS), and kinematic analysis of passive and active ankle ROM. Results: BoNT-A determined a significant reduction of spasticity evaluated by MAS with a reduction of positive effects after 4months (p<0.05); MTS highlighted the efficacy only 90 days after injection (p<0.05). rESWT decreased MAS values at the end and 30 days later the treatment (p<0.01); MTS values showed instead a prolonged effect (p<0.01). BoNT-A determined a gain of passive and active ankle ROM, persisting along with treatment and peaking the maximum value after rESWT (p<0.05). Conclusions: rESWT can prolong BoNT-A effect inducing a significant reduction of spasticity and improvement in passive and active ankle ROM in MS patients. The use of rESWT following BoNT-A injection is useful to avoid some limitations and to prolong the therapeutic effects of BoNT-A therapy. (www.actabiomedica.it)

Monitoring of a methane-seeping pockmark by cabled benthic observatory (Patras Gulf, Greece)

A new seafloor observatory, the gas monitoring module (GMM), has been developed for continuous and long-term measurements of methane and hydrogen sulphide concentrations in seawater, integrated with temperature (T), pressure (P) and conductivity data at the seafloor. GMM was deployed in April 2004 within an active gas-bearing pockmark in the Gulf of Patras (Greece), at a water depth of 42 m. Through a submarine cable linked to an onshore station, it was possible to remotely check, via direct phone connection, GMM functioning and to receive data in nearreal time. Recordings were carried out in two consecutive campaigns over the periods April–July 2004, and September 2004–January 2005, amounting to a combined dataset of ca. 6.5 months. This represents the first long-term monitoring ever done on gas leakage from pockmarks by means of CH4+H2S+T+P sensors. The results show frequent T and P drops associated with gas peaks, more than 60 events in 6.5 months, likely due to intermittent, pulsation-like seepage. Decreases in temperature in the order of 0.1–1°C (up to 1.7°C) below an ambient T of ca. 17°C (annual average) were associated with short-lived pulses (10–60 min) of increased CH4+H2S concentrations. This seepage “pulsation” can either be an active process driven by pressure build-up in the pockmark sediments, or a passive fluid release due to hydrostatic pressure drops induced by bottom currents cascading into the pockmark depression. Redundancy and comparison of data from different sensors were fundamental to interpret subtle proxy signals of temperature and pressure which would not be understood using only one sensor.Published297-302JCR Journalreserve

NEMO-SN1 (Western Ionian Sea, off Eastern Sicily): A Cabled Abyssal Observatory with Tsunami Early Warning Capability

The NEMO-SN1 (NEutrino Mediterranean Observatory - Submarine Network 1) seafloor observatory is located in the central Mediterranean, Western Ionian Sea, off Eastern Sicily Island (Southern Italy) at 2100 m water depth, 25 km from the harbour of the city of Catania. It is a prototype of cabled deep-sea multiparameter observatory, and the first operating with real-time data transmission in Europe since 2005. NEMO-SN1 is also the first-established node of EMSO (European Multidisciplinary Seafloor Observatory, http://emso-eu.org), one of the European large-scale research infrastructures. EMSO will address long-term monitoring of environmental processes related to marine ecosystems, climate change and geo-hazards. NEMO-SN1 will perform geophysical and environmental long-term monitoring by acquiring seismological, geomagnetic, gravimetric, accelerometric, physico-oceanographic, hydro-acoustic, bio-acoustic measurements to study earthquake and tsunami generation, and to characterize ambient noise which includes marine mammal sounds, and environmental and anthropogenic sources. NEMO-SN1 is also equipped with a prototype tsunami detector, based on the simultaneous measurement of the seismic and bottom pressure signals and a new high performance tsunami detection algorithm. NEMO-SN1 will be a permanent tsunami early warning node in Western Ionian Sea, an area where very destructive earthquakes have occurred in the past, some of them tsunamigenic (e.g., 1693, M=7.5; 1908, M=7.4). Another important feature of NEMO-SN1 is the installation of a low frequency-high sensibility hydrophone and two (scalar and vector, respectively) magnetometers. The objective is to improve the tsunami detection capability of SN1 through the recognition of tsunami-induced hydro-acoustic and electro-magnetic precursors.SubmittedRhodes, Greece3A. Ambiente Marinorestricte

Growth of Ordered Iron Oxide Nanowires for Photo-electrochemical Water Oxidation

This work reports the synthesis of ordered and vertically aligned iron oxide nanowires for photo-electrochemical (PEC) water oxidation. The nanowires exhibited promising PEC activity for water oxidation with saturated photocurrents of ∼0.8 mA cm-2 at 1.23 V vs RHE. Various factors inevitably affect their photochemical activity such as crystallinity, morphology, compositional gradient, and surface states. They were studied with HRTEM, EELS, and Raman shift techniques. The nanowires had complex compositional and morphological structures at nano and atomic scales. The nanowires annealed at 350 °C had an outer shell dominated by Fe3+ cations, while the core had mixed oxidation states of iron cations (+2 and +3). In contrast, nanowires annealed at 450 °C are fully oxidized with Fe3+ cations only and were found to be more active. At the same time, we observed anisotropic compositional gradients of nickel cations inside the iron oxide, originating from the nickel support film. Our work shows that the methodology used can affect the composition of the surface and near surface of the grown nanowires. It therefore points out the importance of a detailed analysis, in order to obtain a realistic structure-activity relationship in photo-electrocatalysis

Measuring GNSS ionospheric total electron content at Concordia, and application to L-band radiometers

<p>In the framework of the project BIS - Bipolar Ionospheric Scintillation and Total Electron Content Monitoring, the ISACCO-DMC0 and ISACCO-DMC1 permanent monitoring stations were installed in 2008. The principal scope of the stations is to measure the ionospheric total electron content (TEC) and to monitor the ionospheric scintillations, using high-sampling-frequency global positioning system (GPS) ionospheric scintillation and TEC monitor (GISTM) receivers. The disturbances that the ionosphere can induce on the electromagnetic signals emitted by the Global Navigation Satellite System constellations are due to the presence of electron density anomalies in the ionosphere, which are particularly frequent at high latitudes, where the upper atmosphere is highly sensitive to perturbations coming from outer space. With the development of present and future low-frequency space-borne microwave missions (e.g., Soil Moisture and Ocean Salinity [SMOS], Aquarius, and Soil Moisture Active Passive missions), there is an increasing need to estimate the effects of the ionosphere on the propagation of electromagnetic waves that affects satellite measurements. As an example, how the TEC data collected at Concordia station are useful for the calibration of the European Space Agency SMOS data within the framework of an experiment promoted by the European Space Agency (known as DOMEX) will be discussed. The present report shows the ability of the GISTM station to monitor ionospheric scintillation and TEC, which indicates that only the use of continuous GPS measurements can provide accurate information on TEC variability, which is necessary for continuous calibration of satellite data.</p

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by 40K decays but it can detect other natural (e.g., 238U,232Th) and anthropogenic radio-nuclides (e.g., 137Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea.In press4.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalope