Electron-acoustic-phonon scattering and electron relaxation in two-coupled quantum rings

Electron relaxation, induced by acoustic phonons, is studied for coupled quantum rings in the presence of external fields, both electric and magnetic. We address the problem of a single electron in vertically coupled GaAs quantum rings. Electron-phonon interaction is accounted for both deformation potential and piezoelectric field coupling mechanisms. Depending on the external fields, the ring radii and the separation between the rings, we show that the two different couplings have different weights and importance. Significant oscillations are found in the scattering rates from electron excited states to the ground state, as a function of either the geometry of the system or the external fields.Comment: 17 pages, 8 figures, to appear in Journal of Applied Physic

Sublimation of the Endohedral Fullerene Er3N@C80

The heat of sublimation of the endohedral metallofullerene Er3N@C80 was measured via Knudsen effusion mass spectrometry. The large molecule consists of a C80 fullerene cage which is stabilized by comprising a complex of three erbium atoms bounded to a nitrogen atom and has a mass of 1475 amu. The mass spectrum at a temperature of 1045 K and the relative intensities of the thermal fractions of Er3N@C80 are provided. We also discuss possible thermal decomposition processes for these particles. By measuring the quantity of evaporated molecules in thermal equilibrium through a quadrupole mass spectrometer in a temperature range between 782 K and 1128 K, a value for the sublimation enthalpy of Hsub = 237 +-7 kJ/mol is obtained from the second law method.Comment: Phys. Chem. Chem. Phys., 2010, Advance Articl

Verbal comprehension of university students

This paper presents the preliminary results of a broader research on performance and selfperception in reading and writing of university students. In particular, it focuses on verbal comprehension given its connection with reading comprehension. Reading comprehension is crucial, especially while constructing a situational model—achieved by integrating the information provided in the text with relevant prior knowledge. A random pilot sample of 60 students from third year, male and female, of an average age of 23 was selected. The Vocabulary, Information and Analogies tests from WAIS III were administered. The Verbal Comprehension findings show central tendency scores similar to those of the standardization sample with minor dispersion, with specific cases of scores in the lower average limit. Several comments are given on the performance of university students and other observations regarding the type of mistakes made in the answers provided which deserve further considerations. Preliminary conclusions point to a lack of and/or insufficient information, conceptual confusion with some terms of relatively high frequency and difficulties in the conceptualization process. These preliminary findings deserve further attention due to their impact in successful learning from texts.Facultad de Psicologí

THE TOPOGRAPHIC SIGN - FROM MODERN TO HISTORIC CARTOGRAPHY - AS A METHOD AND AN ISTRUMENT OF KNOWLEDGE IN ARCHAEOLOGICAL AND LANDSCAPE FIELDS

Viene presentato uno stralcio, da un più ampio studio relativo all’area collinare tra Modena e Bologna, volto alla ricostruzione del paesaggio antico, con particolare riguardo alla trasformazione dei toponimi, della rete idrografica, dell’uso del suolo e del reticolo insediativo. La ricerca si è avvalsa di numerosi documenti cartografici moderni e storici, anche inediti. I primi risultati hanno messo in evidenza la validità del metodo seguito, grazie alle tante informazioni che gli strumenti utilizzati hanno offerto per ricostruire i complessi rapporti territoriali uomo-ambiente. Un primo concreto risultato è stato la realizzazione della cartoguida e dell’audioguida dell’Ecomuseo della Collina e del Vino di Castello di Serravalle (Bologna), strumenti didattico-educativi che permettono al visitatore di costruire il proprio itinerario di visita, in base a esigenze ed interessi personali.It is presented an extract of a larger study about the hill area between Modena and Bologna. The aim of this research is the reconstruction of the ancient landscape, whit particular attention to the transformation of toponyms, rivers courses, soil use and human settlement network. The research is based on a large number of cartographic documents, modern and historic, unpublished too. The first outcomes have drawn attention to the validity of the applied method, and to the several information this way obtained, which reconstruct the complex territorial relationships between man and environment. A first outcome was the map-guide and the audio-guide of the Ecomuseum of Hill and Wine of Castello di Serravalle (Bologna): two didactical and educational tools that allow to the visitors the creation of their own itinerary, based on personal needs and interests

The Dissocationi Energy and Heat of Formation of the Molecule NaCu

The reaction NaCu(g) = Na(g) + Cu(g) has been investigated by means of high-temperature mass-spectrometry, using a double oven technique. From the measured reaction enthalpy the dissociation energy D0 0(NaCu) = 41.2 ± 4.0 kcal mol-1 or 172.4 ± 16.7 kJ mol-1 and the standard heat of formation, ΔH0 f, 298 [NaCu(g)] = 64.3 ± 4.4 kcal mol-1 or 269.0 ± 18.4 kJ mol-1 have been obtained. The experimental dissociation energy of NaCu(g) is markedly lower than the value of 54 kcal mol-1 calculated after the Pauling model of a polar single bond

Philosophical and epistemological debate in Italy within an ethical perspective of Earth sciences

During the recent "Geoitalia" national congress, the Italian scientific community tackled questions concerning the philosophy and sociology of Earth Sciences. The topics discussed and reported in this article were: the overall identity of E.S.; the validation procedures of data, theories and models; the power of attraction exerted by the philosophy of physics - exact science par excellence - with respect to E.S

De la dislexia a la comprensión lectora : Estrategias de intervención

En este simposio se hará referencia a las perspectivas actuales sobre los problemas que aparecen en el tratamiento del lenguaje escrito más allá de las dificultades inherentes a su adquisición. En especial se considerarán las cuestiones involucradas en la comprensión de textos, tema que en los últimos años ha ganado un lugar de privilegio en los estudios psicolingüísticos y educacionales, ya que constituye una de las competencias fundamentales. Sin embargo, son muchos los estudiantes que no logran alcanzar estándares mínimos, con la consecuencia de tropezar con dificultades para procesar distintas formas de texto escrito. Esto genera una preocupación creciente y continua que surge de la percepción de los docentes y de los padres, motivando el interés en todos los países del mundo, que se expresa en muchos casos en campañas a distintos niveles gubernamentales.Eje: Psicología y Educación Publicado en: Memorias del IV Congreso Internacional de Investigación de la Facultad de Psicología: conocimiento y práctica profesional: perspectivas y problemáticas actuales - Tomo IIFacultad de Psicologí

Desarrollo y evaluación de proyectos de investigación : Impacto en la formación de grado y posgrado

La investigación en psicología es una cuestión de permanente interés, que no sólo trae a colación aspectos epistemológicos y metodológicos, sino también institucionales y de práctica concreta.Simposio: La formación en investigaciónFacultad de Psicologí

ESI-MS, ESI-MS/MS fingerprint and LC-ESI-MS analysis of proathocyanidins from Bursera simaruba sarg bark.

Direct flow injection/electrospray ionization/ion trap tandem mass spectrometry was used to investigate the presence of proanthocyanidins (PAs) in the methanolic extract of B. simaruba bark. Additionally, an LC-ESI-MS qualitative study was performed by using a monolithic stationary phase. The fragmentation pattern obtained evidenced the presence in B. simaruba bark of PAs belonging to the series of polymers of epicatechin, along with their glycosilated derivatives