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)     

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.     

Ricerca random pesata in tavole hash

A new search method in hash table is presented: collisions are resolved by a pseudorandom function depending on the key, in such a way that the search is free from clustering and at a comparable cost with respect to previous methods.     

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.     

Production of aggregate from non-metallic automotive shredder residues

In this paper, the results of an experimentation on the production of granules suitable to be used as aggregates in cementitious or asphalt mixes are presented and discussed. The granules were obtained by granulating the non-metallic fraction of automotive shredder residues. In a preliminary separation step the fluff fraction containing mainly inert and non-metallic materials was sieved and analyzed for the metal content. In the following granulation step, the sieved fraction was mixed with binding materials, fly ash and a densifier agent, to produce granules of 5-30 mm of diameter and up to 1400 kg/m3 of specific weight. The granulation was carried out at room temperature in a rotating tank. Concrete samples prepared using as aggregates the produced granules showed a specific weight up to 1800 kg/m3 and a compressive strength up to about 55% of reference samples prepared using a calcareous aggregate, depending on the fluff content of the mixes, and on the nature of the binder and of the other components used.