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A preliminary numerical analysis of the power transfer efficiency (PTE) for the forward link of near-field (NF) ultra high frequency (UHF)-radio frequency identification (RFID) systems is addressed in this paper, by resorting to an impedance matrix approach where the matrix entries are determined through full-wave simulations. The paper is aimed to quantify the NF-coupling effects on the PTE, as a function of the distance between the reader and tag antennas. To allow for a PTE comparison between different reader and tag antenna pairs, a benchmarking tag-loading condition has been assumed, where the tag antenna is loaded with the impedance that maximizes the PTE. In a more realistic loading condition, the load impedance is assumed as equal to the conjugate of the tag antenna input impedance. Full-wave simulations use accurate antenna models of commercial UHF-RFID passive tags and reader antennas. Finally, a “shape-matched antenna” configuration has been selected, where the reader antenna is assumed as identical to the tag antenna. It is shown that the above configuration could be a valuable compact solution, at least for those systems where the relative orientation/position between the tag and reader antennas can be controlled, and their separation is of the order of a few centimeters or less.
Understanding how young stars and their circumstellar disks form and evolve is key to explain how planets form. The evolution of the star and the disk is regulated by different processes, both internal to the system or related to their environment. The former include accretion of material onto the central star, wind emission, and photoevaporation of the disk due to high-energy radiation from the central star. These are best studied spectroscopically, and the distance to the star is a key parameter in all these studies. Here we present new estimates of the distance to a complex of nearby star-forming clouds obtained combining TGAS distances with measurement of extinction on the line of sight. Furthermore, we show how we plan to study the effects of the environment on the evolution of disks with Gaia, using a kinematic modelling code we have developed to model young star-forming regions.
Results of observations made with the Danjon astrolabe at Merate Observatory in the period from 1970 through 1976 were analyzed. The observational program and methods have been discussed previously (Buffoni et al., 1975a, b). The observational accuracy of the observations was compared with that of the Paris and San Fernando instruments. No substantial difference was found.
Since 1991, in France, studies on the conditioning of iodine were carried out to assess the potential of several specific inorganic host matrices. The apatite family has been mainly studied because of its good chemical durability and its ability to confine iodine over geological time scales. A lead-bearing apatite, Pb10(VO4)4.8(PO4)1.2I2, and a calcium-bearing apatite, Ca10(PO4)6(OH)2-x(IO3)x, were selected on the basis of their incorporation rate (between 7 and 10 wt.%) and a satisfactory resistance to leaching (V0(50 °C, pure water) ∼ 10-2 g.m-2.d-1; Vr(50 °C, pure water) < 10-4 g.m-2.d-1). However, with such materials, the removal of open porosity requires non conventional sintering techniques like spark plasma sintering to decrease the surface exposed to water. This is why, in parallel, other matrices, like silver phosphate glasses, have also been investigated. To improve the chemical durability and thermal properties of these glasses, cross-linking reagents were added to their formulation.
Prenatal stress is hypothesized to have a disruptive impact on neurodevelopmental trajectories, but few human studies have been conducted on the long-term neural correlates of prenatal exposure to stress. The aim of this study was to explore the relationship between prenatal stress exposure and gray-matter volume and resting-state functional connectivity in a sample of 35 healthy women aged 14–40 years.
Voxel-based morphometry and functional connectivity analyses were performed on the whole brain and in specific regions of interest (hippocampus and amygdala). Data about prenatal/postnatal stress and obstetric complications were obtained by interviewing participants and their mothers, and reviewing obstetric records.
Higher prenatal stress was associated with decreased gray-matter volume in the left medial temporal lobe (MTL) and both amygdalae, but not the hippocampus. Variance in gray-matter volume of these brain areas significantly correlated with depressive symptoms, after statistically adjusting for the effects of age, postnatal stress and obstetric complications. Prenatal stress showed a positive linear relationship with functional connectivity between the left MTL and the pregenual cortex. Moreover, connectivity between the left MTL and the left medial-orbitofrontal cortex partially explained variance in the depressive symptoms of offspring.
In young women, exposure to prenatal stress showed a relationship with the morphometry and functional connectivity of brain areas involved in the pathophysiology of depressive disorders. These data provide evidence in favor of the hypothesis that early exposure to stress affects brain development and identified the MTL and amygdalae as possible targets of such exposure.
We present preliminary results of a detailed study of the accretion, stellar, and wind properties of transitional disks (TDs) carried out with the X-Shooter spectrograph. Combining new and archival spectra, we collected a sample of more than 20 TDs from different nearby star-forming regions. Our sample includes objects with both small (<5-15 AU) and large (>20–30 AU) known inner hole size from the literature (either from mm-observations or IR SED fitting). We check their stellar parameters (Teff, L*, AV, M*) and derive their accretion properties (Lacc, Ṁacc) in a self-consistent way, which makes use of the wide wavelength coverage of X-Shooter, and study their wind properties by mean of different forbidden emission lines analysis.
Salmeterol, a long-acting β2-adrenergic receptor agonist used for the treatment of asthma and chronic obstructive pulmonary disease, has an adverse effects profile that is similar to that of salbutamol and other β2-agonists. We report a sympathomimetic syndrome with metabolic acidosis and hyperlactatemia after intentional inhalation of salmeterol in a suicide attempt. A 16-year-old female patient was admitted to the emergency department approximately 2 hours after having inhaled 60 puffs of a combination of salmeterol xinafoate 25 μg and fluticasone propionate 50 μg. She presented in an anxious state with complaints of palpitations and chest pain. The electrocardiogram demonstrated sinus tachycardia and ST-segment depression in the inferior and anterolateral leads. Laboratory findings showed hypokalemia, hypophosphatemia, and lactic acidosis. Cardiac troponin I and creatine kinase MB remained within the normal range. Treatment was supportive and included intravenous fluids and cautious potassium supplementation. The next day, electrocardiographic and laboratory findings returned to normal. We hypothesize that stimulation of β2-adrenergic receptors by inhalation of salmeterol caused this patient's lactic acidosis. This observation is consistent with the hypothesis that the hyperlactatemia observed during asthma attacks is due in part to the administration of high doses of β2-agonists. Salmeterol overdose by inhalation appears to be sufficient to cause lactic acidosis.
A 33-year-old woman presented with a three-day history of an abscess in the left alar region, four weeks after drainage of a breast abscess. The later infection was confirmed to be due to Panton–Valentine leukocidin positive, methicillin-resistant Staphylococcus aureus. This report aims to raise awareness of such infections, and to advise when Panton–Valentine leukocidin toxin testing is appropriate.
Case report and discussion.
Although superficial Panton–Valentine leukocidin positive Staphylococcus aureus infections are relatively benign, more serious infections can be potentially life-threatening. Clinicians should be able to identify the features of potential Panton–Valentine leukocidin positive Staphylococcus aureus infection, in order to implement appropriate therapy.
Clinicians need to be aware of Panton–Valentine leukocidin positive Staphylococcus aureus infections, and should ask specific questions when investigating the clinical history of patients with recurrent abscesses, as this bacterial strain is not routinely assessed by microbiology departments. If such an infection is suspected, clinicians should be aware of local protocols regarding toxin testing, antibiotic choice and decolonisation agents.
Sulphur is present in several kinds of nuclear waste destined to confinement in a glass matrix.. These species are hardly incorporated in borosilicate glasses, due to the poor miscibility of molten sulphates and glass melt at high temperature. This point constitutes one of the main technological difficulties in the current fabrication of nuclear glasses. Several studies carried out in the last two decades indicate that the liquid state miscibility of sulphates and glass melt, determining the waste incorporation in the final glass, is dependent on the composition of the glass and on the temperature and duration of its preparation. In particular, the ratios K = [SiO2] / [B2O3] and R = [Na2O] / [B2O3] (where [.] indicates the mol %), as well as the presence of V2O5 in the glass matrix play an important role in the determination of both kinetics and thermodynamics of sulphates incorporation in the vitreous matrix. In this work a study on the physico-chemical effects of the ratio R, the melt reactivity, the type of sulphate added, and the presence of V2O5 on the solubility of sulphates in borosilico-vanadate glasses is presented.
Glass samples were prepared at the laboratory scale (up to 50-100 g) by melting oxide and sulphate powders in Pt/Au or Pt/Rh crucibles at a fixed viscosity level of 100 Po in air. Several glass specimens were powdered and re-melted at 1200°C in the presence of sulphates in order to simulate conditions as close as possible to those of an industrial melter. XRF and ICP AES chemical analysis, SEM EDS and Raman spectroscopy were employed to characterise the fabricated samples. Raman spectra, in particular, reveal the structural modifications that condition the sulphate incorporation in the glass. A critical review of the obtained results is compared with the literature data, to yield a more systematic description of the mentioned factors effects on sulphate behaviour in the borosilico-vanadate / system.
The aim of these measurements is to study how a silica saturated solution influences leaching from a HLW glass matrix. Cylindrical samples of I117 borosilicate glasses were suspended in polycarbonate vials containing a SiO2 saturated solution and leached at temperature of 50 or 80°C for different times (from 1/2 to 28 days). Mass loss, X-ray photoelectron spectroscopy (XPS) and nuclear reaction techniques were applied for post leaching tests on the glass samples.
Analysis of boron and sodium released from the glass were performed in the leachate. Sodium and boron release followed a square root time dependence at all the observed leaching times.
XPS measurements revealed a surface increase of silicon content with respect to unleached samples, with aluminium showing the same behaviour as silicon. The presence of the layer enriched in silicon and aluminium does not stop the release of sodium and boron, whereas the mass loss does slow down because of the formation of aluminio-silicate compounds.
Structural changes occurring at the surface of leached borosilicate glasses containing 3%wt of uranium have been investigated using fluores- cence EXAFS spectroscopy at grazing incidence. X-ray penetration depths between 30 Å and above 1000 Å are possible by varying the incidence angle of the X-ray monochromatic radiation in the vicinity of the critical angle for total external reflection, øc. This enables the surface and bulk structure to be compared. It is found that a local increase in uranium concentration takes place near the surface of the glass during the first 30 minutes of leaching time. Uranium is coordinated with oxygen and other uranium atoms. The local distribution can be modelled by a square planar island structure comprised of uranyl-type units. This structure changes with corrosion time. After 30 minutes of leaching there is evidence of partial removal of the surface layer.
Surface analysis has been conducted on samples leached in a Soxhlet apparatus at 100°C in presence and in absence of air. The XPS and RBS techniques were applied to analyse the content of the silicon, iron and uranium while the nuclear reaction method was utilized to analyse the hydrogen content. The anoxic environment favours the release of iron while decreasing the dissolution of uranium. Hydrogen content is always higher in samples leached in presence of air.
Silicon depletion is evident in all cases. The diffusion process seems to regulate the growth of the layer on the glass surface. After long leaching time a detachment, at least partial, of this layer is observed.
Surface analysis has been conducted on samples leached in a Sochlet apparatus at 100°C in the presence and in the absence of air. The XPS technique was applied to analyse the content of iron and silicon while the nuclear reaction method was utilized to analyse the content of hydrogen. Samples leached in argon atmosphere have shown a smaller content of iron and silicon with respect to the samples leached in air atmosphere. The H concentration has shown the same behaviour. The results are discussed in terms of possible formation of iron compounds in the different redox condition and of their different stabilities and in terms of their efficiency in reducing exchange between Na+ and H+ ions.
The results of recent measurements of optical absorption, etching rate and transmission electron microscopy in pure silica and borosilicate glasses are reported and discussed. At dose saturation conditions, the dependence of the optical density associated with the production of single atomic defects from the mass of the impinging particle shows a marked saturation at masses ≥ 20 amu. The corresponding etching rates increase by about 4 times with respect to unirradiated samples. In borosilicate glasses, the temperature dependence of the threshold dose rate of electrons to initiate the nucleation of bubbles shows a marked increase from about 300° to 600° K.
The results of previous optical absorption experiments aiming to investigate the behaviour of atomic defects in silica based glasses irradiated with various types of particles have been extended to examine the effects of multiple irradiations which take place during long term storage of glasses containing HLW. In addition, point defect clustering phenomena have been investigated by means of high voltage transmission electron microscopy. It has been found that due to the large number of defects already present in amorphous silica prior to irradiations, the contributions of different bombarding particles to the total damage cannot be considered fully additive in terms of the relative number of displaced atoms, but some consideration has to be made of defect interactions and ionization damage. Clustering effects, while being absent in pure silica, are present in borosilicates at large dose rates (≳1022 electrons m−2 sec−1 ). At lower beam current densities and doses comparable to those achieved after 10–100 years of HLW storage, phase separation into a microcrystalline compound has been detected by transmission electron microscopy.
This paper presents CODES – COoperative Music Prototype DESign, a Web-based environment for cooperative music prototyping. Its main goal is to allow any user – especially those with no expertise in music – to draft musical pieces collectively, in a prototyping manner. So, such musical sketches – we call them music prototypes – can be repeatedly tested, listened to, and modified, not only by their original creators but also by the online partners that will cooperate in their refinement, until their final form is reached. CODES enables sharing of knowledge by means of rich interaction and argumentation mechanisms associated to each prototype modification, which are also secure ways of providing awareness to this asynchronous collaborative environment. In this paper, we present the concept of music prototyping and introduce the main aspects related to cooperative prototyping of musical pieces, focusing on issues concerning a musical piece as a collective creation of a virtual community. We will also show some usage examples as a means to describe the overall architecture, behaviour and potentials of the CODES environment.