RingO: an experimental WDM optical packet network for metro applications

This paper presents Ring Optical Network (RingO), a wavelength-division-multiplexing (WDM), ring-based, optical packet network suitable for a high-capacity metro environment. We present three alternative architectural designs and elaborate on the effectiveness of optic with respect to electronic technologies, trying to identify an optimal mix. We present the design and prototyping of a simple but efficient access control protocol, based upon the equivalence of the proposed network architecture with input-buffering packet switches. We discuss the problem of node allocation to WDM channels, which can be viewed as a particular optical network design problem. We, finally, briefly illustrate the fault protection properties of the RingO architecture. The main contribution of this paper is the identification and experimental validation of an innovative optical network architecture, which is feasible and cost effective with technologies available today, and can be a valid alternative to more consolidated solutions in metro applications.     

Selective CO-oxidation over Ru-based catalysts in H2-rich gas for fuel cell applications

Topics in Catalysis - Ru-based catalysts supported on A zeolites and alumina were synthesised, characterised (XRD, SEM-EDS, TPR) and tested under realistic conditions for the preferential oxidation...     

Effect of subcritical CO2 on the structural and electrical properties of ORMOCERS-APE systems based on Zr and Al

Two series of hybrid inorganic-organic polymer electrolytes of the organically modified ceramics as polymer electrolytes (ORMOCERS-APE) type with formulas {Al[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n (1.85 ≤ ρ ≤ 2.24, 0 ≤ z ≤ 1.06) and {Zr[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n (1.80 ≤ ρ ≤ 1.99, 0 ≤ z ≤ 0.90) were treated with CO₂ in subcritical conditions (293 K and 5 MPa). The effect of CO₂ on the samples was investigated by using ESEM, thermal analysis (TG and DSC) and broad band dielectric spectroscopy (BDS).Both complexes {Al[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n and {Zr[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n after CO₂ treatment exhibited a change in the segmental relaxation with respect to the untreated samples. This phenomenon has been interpreted in terms of higher portion of free volume in the samples. The CO₂ treatment primarily lowered the conductivity of {Al[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n complexes of about one order of magnitude, as opposed to {Zr[O(CH₂CH₂O)_8.7]_ρ/(LiClO₄)_z}_n complexes, where an increment of two orders of magnitude was observed. In both cases the conductivity of the treated and untreated materials versus the reciprocal absolute temperature presents the typical Vogel-Tamman-Fulcher (VTF) behavior. The different effects on the conductivities of the treated complexes are explained in terms of the modified anion-trapping ability of Al centers and in terms of the interactions of subcritical CO₂ with the host polymer and the salt. Insight about the conductivity mechanisms were provided by the study of the VTF parameters and the relaxation times determined from the Debye peaks of the imaginary resistivity, the imaginary permittivity and the correlated motion analysis.     

Feature and rule selection in categorization tasks.

The process by which stimuli are assigned to categories has been traditionally conceptualized as bottom-up. Accordingly, stimulus features are supposed to be the fundamental units of analysis, and categorization to be accomplished on the basis of feature category correlations (cue validities). Alternatively, top-down processes are invoked, in which case one begins with a given categorization rule and then assigns stimuli to categories on that basis. Bottom-up and top-down views share a fundamental weakness, namely, they are unable to specify how features or rules, respectively, are acquired. This difficulty can be overcome if it is assumed that the process starts with neither features nor rules, but with stimuli. Then, as a result of experience with stimuli belonging to different categories, the cognitive system discovers and uses locally constructed features that maximally discriminate between the categories at hand. According to this view, the relationship between a target and a contrast category is the main factor affecting what subjects learn about each. Two experiments were conducted to explore this hypothesis. Both experiments support the notion that the relationship between the target and contrast category significantly determines which critical features are extracted as being defining of either category. In particular, it determines the level of generality of these features. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within-story recalls and the retention of ideas in prose processing.

Examined the facilitatory effect of within-story recalls on later recalls as a function of the interval elapsed between presentation of a to-be-recalled idea and its 1st recall, using 75 undergraduates. Results show that (1) specific ideas contained in a prose passage were forgotten rapidly during story presentation, (2) only those ideas that were successfully recalled during story presentation were likely to be recalled on later tests, and (3) the probability of a later recall given a successful within-story recall increased with retention interval. Findings suggest that frequent test questions, interspersed while listening to or reading an expository passage, were most beneficial for long-term retention. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exclusive radical radiotherapy of laryngeal tumors: 10-year experience

Exclusive irradiation is used to treat primary neoplasms localized to the larynx because it is known to be able to cure, or at least control, the disease in a high percentage of cases without affecting speech. We report our ten-year experience in the Radiotherapy Department of Chieti Hospital. From 1985 to 1994, exclusive radiotherapy was used to treat 87 patients bearing histologically proved epidermoid carcinomas of the larynx. The patients average age was 67 years. The primary site was the glottis in 64 cases and the supraglottic and subglottic areas in 21 and 2 cases, respectively. The lymph nodes were clinically positive in 8 patients (9%) and negative in 79 (91%). The minimum follow-up was 20 months. All the patients were treated with cobalt 60 beams; the daily dose was 2 Gy, fractionation was 5 days a week. Average tumor dose was 64 Gy (range: 55-70 Gy). Disease-free survival actuarial curves show 72% five-year survival for glottic cancer (75% for N0, 80% for T1 and 61% for T2-T3-T4 cases) and 21% for supraglottic cancer (25% for N0 cases). To conclude, irradiation is confirmed to be a useful tool to treat early laryngeal cancer, while new combinations of surgery, chemotherapy and irradiation are needed to treat locally advanced cancer.     

Galanin positively modulates prolactin secretion in normal women

It is widely accepted that, in man, galanin, a neuropeptide, has a clear GH-releasing effect while its stimulatory influence on PRL secretion is matter of debate. To clarify this point, in 6 normal young women (23-35 yr) in their early follicular phase, we studied the effect of galanin (pGAL, 80 pmol/kg. min infused i.v. over 60 min) on both basal and arginine (ARG, 0.5 g/kg i.v. in 30 min), TRH (400 micrograms i.v. as a bolus at 0 min) or metoclopramide (MCP, 10 mg i.v. as a bolus at 0 min)-stimulated PRL secretion. GAL infusion failed to significantly increase basal PRL levels (peak vs baseline: 12.2 +/- 3.6 vs 8.7 +/- 1.2 micrograms/L) but counteracted the spontaneous PRL decrease observed during saline infusion (AUC: 1216.6 +/- 282.1 vs 672.0 +/- 94.5 micrograms.min/L; p < 0.05). GAL infusion clearly enhanced the PRL response to TRH (AUC: 5806.3 +/- 743.0 vs 3952.1 +/- 423.9 micrograms.min/L, p < 0.05) and ARG (AUC: 3676.8 +/- 382.6 vs 2638.9 +/- 287.0 micrograms.min/L, p < 0.05), respectively. On the other hand, GAL failed to modify the MCP-induced PRL response (AUC: 15409.5 +/- 2085.3 vs 14,787.9 +/- 2045.5 micrograms.min/L). The PRL response to MCP was higher than that to TRH (p < 0.01) which, in turn, was higher than that to ARG (p < 0.01). During GAL infusion, the PRL response to TRH or ARG remained lower (p < 0.01) than that after MCP administration. Thus, in conclusion, present data demonstrate that in normal women galanin enhances the PRL response to ARG and TRH but fails to modify that induced by dopamine receptor blockade with metoclopramide. Based on evidence that the inhibition of central dopaminergic activity inhibits the lactotrope responsiveness to dopaminergic antagonists or TRH, it is unlikely that galanin influences PRL secretion via inhibition of dopaminergic tone.     

PVC membrane potentiometric sensor based on 5-pyridino-2,8-dithia[9](2,9)-1,10-phenanthroline-phane for selective determination of neodymium(III)

Spectrofluorometric studies on the binding properties of 5-pyridino-2,8-dithia[9](2,9)-1,10-phenanthrolinephane (L) toward La3+, Sm3+, Gd3+, Yb3+, and Nd3+ in methanol solution revealed the occurrence of both 1:1 and 2:1 (ligand/metal) complexation with a stability order of Nd3+ > Yb3+ > Gd3+ > Sm3+ > La3+. Consequently, L was used as a suitable neutral ionophore for the preparation of a novel polymeric membrane-selective electrode for Nd3+ ion. The electrode exhibited a Nernstian response over a wide concentration range (1.0 x 10(-6)-1.0 x 10(-2) M) with a low limit of detection of 7.9 x 10(-7) M. The electrode possesses a fast response time of <5 s and can be used for at least 9 weeks without observing any considerable deviation. The proposed electrode revealed a very good selectivity for Nd3+ over a wide variety of alkali, alkaline earth, transition, and heavy metal ions, including members of the lanthanide family other than Nd3+. The potentiometric response of the electrode is independent of the pH of test solution in the pH range 4.0-6.5. The proposed electrode was successfully applied to the recovery of Nd3+ ion from tap water samples and, also, as an indicator electrode, in potentiometric titration of neodymium(III) ions.     

Improved algorithm for calculations of Rayleigh-scattering optical depth in standard atmospheres

Precise calculations of the total Rayleigh-scattering optical depth have been performed at 88 wavelengths ranging from 0.20 to 4.00 microm for the six well-known standard atmosphere models by integrating the volume Rayleigh-scattering coefficient along the vertical atmospheric path from sea level to a 120-km height. The coefficient was determined by use of an improved algorithm based on the Ciddor algorithm [Appl. Opt. 35, 1566 (1996)], extended by us over the 0.20-0.23-microm wavelength range to evaluate the moist air refractive index as a function of wavelength, air pressure, temperature, water-vapor partial pressure, and CO2 volume concentration. The King depolarization factor was also defined taking into account the moisture conditions of air. The results indicate that the influence of water vapor on Rayleigh scattering cannot be neglected at tropospheric altitudes: for standard atmospheric conditions represented in terms of the U.S. Standard Atmosphere (1976) model, the relative variations produced by water vapor in the Rayleigh scattering parameters at a 0.50-microm wavelength turn out to be equal to -0.10% in the moist air refractivity at sea level (where the water-vapor partial pressure is equal to approximately 7.8 hPa), -0.04% in the sea-level King factor, -0.24% in the sea-level Rayleigh-scattering cross section, and -0.06% in the Rayleigh-scattering optical depth.