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Pottery-manufacturing sequences can act as proxies for human migration and interaction. A good example is provided by the ‘spiralled patchwork technology’ (SPT) identified at two key early farming sites in the Ligurian-Provencal Arc in the north-west of the Italian peninsula. SPT is distinct from the ceramic technology used by early farmer communities in south-east Italy that shows technical continuity with the southern Balkans. Macroscopic analysis and micro-computed tomography suggests the presence of two communities of practice, and thus two distinct social groups in the northern Mediterranean: one of southern Balkan tradition, the other (associated with SPT) of as yet unknown origin. The identification of SPT opens up the exciting possibility of tracing the origins and migrations of a second distinct group of early farmers into Southern Europe.
We analyze the anisotropies in the extragalactic infrared background and in the source counts in standard cosmology perturbed by large-scale, small-amplitude density fluctuations. The dipole anisotropy of the diffuse background is connected to the dipole of the cosmic background radiation and of the source counts, and a full consistency with a large (≃ 7%) anisotropy in the IRAS source counts is found to imply a low density (Ω0 ≃ 0.2) universe, contrary to a previous claim. We analyze also higher order harmonics. Using the IRAS Low-Resolution All-Sky Maps we obtain an upper limit of 0.17MJy/sr on the dipole of the 100 μm background and show that it is consistent with a source-count anisotropy of 7% only for a low intensity, I ≤ 1.2 M Jy/sr, of the background itself.
Nafion α-relaxation has been the subject of intense investigations as it regulates the performance of electric actuators and polymer electrolyte fuel cells (PEMFC). Dielectric spectroscopy and atomic force microscopy (AFM) measurements of Nafion membranes allowed identifying the conformation transition of the polymeric aggregates as the process underlying the α-transition. The dielectric permittivity curves of Nafion showed that for temperatures T > 120 °C, the α-relaxation displaces to lower frequencies. Such unusual behavior was attributed to an elongation of Nafion polymeric aggregates occurring at T ∼ 120 °C and is in agreement with both water uptake measurements and morphological changes inferred from AFM analyses.
We present a detailed study carried out on oxide buffer layers grown by Metal-Organic Decomposition (MOD) on metallic substrates for YBa2Cu3O7-x (YBCO) coated conductor applications. Precursor solutions have been made starting from acetates or pentanedionates and characterized by means of Differential Scanning Calorimetry (DSC) and Thermogravimetric (TG) analyses coupled with Fourier Transform Infra-Red spectroscopy (FT-IR). Thin buffer layers have been grown by spin-coating on Ni-5at.%W substrates. X-ray diffraction spectra (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) have been employed in order to optimize buffer layers in terms of film microstructure and surface quality, with the final aims of producing a suitable template for YBCO growth. It will be shown that the optimization of the recrystallization process can lead to high quality buffer layer allowing the growth of YBCO films showing good superconductive properties.
Backside sample preparation is a well-known method to help circumvent undesired effects and artifacts in the analysis of a sample or device structure. However it remains challenging in the case of thin layers analysis since only a fraction oRelax;f the original sample must remain while removing most or all of the substrate and maintaining a smooth and flat surface suitable for analysis. Here we present a method adapted to the preparation of ultrathin layers grown on pure Si substrates. It consists in a mechanical polishing up to a few remaining microns, followed by a dedicated wet etch. This method can be operated in a routine fashion and yields an extremely flat and smooth surface, without any remaining Si from substrate. It therefore allows precise analysis of the layers of interests with various characterization techniques.
Light-emitting silicon nanocrystals (Si nc) have attracted much interest due to their possible application as optoelectronic devices. The interest for Si nanopowders is enhanced by their photoluminescence (PL) emission intensity that can be very strong at room temperature. Due to the intrinsic biocompatibility of Si nanoparticles, this strong optical emission intensity as well as the long decay time (mean life time around hundred microseconds) make these powders potential candidates as tracers for in-vivo applications.
Si nanopowders were obtained in gram quantities by CO2 laser pyrolysis of silane. The particles in the produced powders are in the size range 10-15 nm. These nanoparticles exhibit strong red photoluminescence after heat treatment. The appearance of intense PL emission is clearly related to the surface oxidation of the powders which must be carefully controlled. Several steps have been identified in the oxidation process. This paper presents a detailed study of the evolution of both the photoluminescence intensity and spectral dependence and of the crystalline structure as a function of the heat treatment. We also show that the nanopowders can be dispersed in liquids and incorporated in gel samples while keeping their intense photoluminescence. This result opens a route towards the fabrication of novel devices
By simulation of X-ray rocking curves of Si-Ge alloys grown on Si by molecular beam epitaxy and of Ge implanted samples, the Ge composition, the linear lattice expansion coefficient, the strain depth-distribution and the static Debye-Waller factor in the MBE alloys have been determined.
The BaR-SPOrt experiment is designed to measure the E-mode
power spectrum of the Cosmic Microwave Background Polarization (CMBP)
in the multipole range 50 < l < 1000.
In the current configuration at 32 GHz
it can explore up to l = 400.
Recent low frequency observations of the target region show that
the synchrotron emission should not contamine the CMBP already at 32 GHz.
A 6-month observation of a 6° × 6° sky area
during the polar night, in ideal
environmental conditions, will allow the Italian-French collaboration
to both measure the E–mode power spectrum with appropriate sensitivity
and perform important tests of the anomalous dust emission.
The BaR-SPOrt 32 GHz instrument, now under test and ready
for operations by Spring 2005, is proposed
for 1–2 years Winter operations at Dome C.
The technique for ultra rapid opioid detoxification is designed to shorten the detoxification period by precipitating withdrawal by the administration of opioid antagonists such as naloxone or naltrexone. This procedure is performed under deep sedation or general anaesthesia to ensure that the patient does not consciously experience the acute withdrawal phase. This strategy has aroused controversy regarding the risk of sedation or anaesthesia in this situation. In the present study, ultra rapid opioid detoxification was carried out in 12 opiate-addicted patients by infusion of naloxone 4 mg for a period of 5 h using controlled ventilation during general anaesthesia, induced and maintained with midazolam, propofol and atracurium. Invasive cardiovascular and respiratory monitoring was performed, and withdrawal signs were evaluated using a graduated scale. Anaesthesia was maintained for another hour after the completion of the naloxone infusion. The validity of this anaesthesia protocol was confirmed by the relative lack of change in the patients’ haemodynamic values associated with mild signs of withdrawal.
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