Dynamical photo-induced electronic properties of molecular junctions

Nanoscale molecular-electronic devices and machines are emerging as promising functional elements, naturally flexible and efficient, for next generation technologies. A deeper understanding of carrier dynamics in molecular junctions is expected to benefit many fields of nanoelectronics and power-devices. We determine time-resolved charge current flowing at donor- acceptor interface in molecular junctions connected to metallic electrodes by means of quantum transport simulations. The current is induced by the interaction of the donor with a Gaussian-shape femtosecond laser pulse. Effects of the molecular internal coupling, metal- molecule tunneling and light-donor coupling on photocurrent are discussed. We then examine the junction working through the time-resolved donor density of states. Non-equilibrium reorganization of hybridized molecular orbitals through the light-donor interaction gives rise to two phenomena: the dynamical Rabi shift and the appearance of Floquet-like states. Such insights into the dynamical photoelectronic structure of molecules are of strong interest for ultrafast spectroscopy, and open avenues toward the possibility of analyzing and controlling the internal properties of quantum nanodevices with pump-push photocurrent spectroscopy

Regression analysis of MCS Intensity and ground motion parameters in Italy and its application in ShakeMap

In Italy, the Mercalli-Cancani-Sieberg, MCS, is the intensity scale in use to describe the level of earthquake ground shaking, and its subsequent effects on communities and on the built environment. This scale differs to some extent from the Mercalli Modified scale in use in other countries and adopted as standard within the USGS-ShakeMap procedure to predict intensities from observed instrumental data. We have assembled a new PGM/MCS-intensity data set from the Italian database of macroseismic information, DBMI04, and the Italian accelerometric database, ITACA. We have determined new regression relations between intensities and PGM parameters (acceleration and velocity). Since both PGM parameters and intensities suffer of consistent uncertainties we have used the orthogonal distance regression technique. The new relations are IMCS = 1.68 ± 0.22 + 2.58 ± 0.14 log P GA, σ = 0.35 and IMCS = 5.11 ± 0.07 + 2.35 ± 0.09 log P GV , σ = 0.26. Tests designed to assess the robustness of the estimated coefficients have shown that single-line parameterizations for the regression are sufficient to model the data within the model uncertainties. The relations have been inserted in the Italian implementation of the USGS-ShakeMap to determine intensity maps from instrumental data and to determine PGM maps from the sole intensity values. Comparisons carried out for earthquakes where both kinds of data are available have shown the general effectiveness of the relations

Regression analysis of MCS Intensity and ground motion parameters in Italy and its application in ShakeMap

In Italy, the Mercalli-Cancani-Sieberg, MCS, is the intensity scale in use to describe the level of earthquake ground shaking, and its subsequent effects on communities and on the built environment. This scale differs to some extent from the Mercalli Modified scale in use in other countries and adopted as standard within the USGS-ShakeMap procedure to predict intensities from observed instrumental data. We have assembled a new PGM/MCS-intensity data set from the Italian database of macroseismic information, DBMI04, and the Italian accelerometric database, ITACA. We have determined new regression relations between intensities and PGM parameters (acceleration and velocity). Since both PGM parameters and intensities suffer of consistent uncertainties we have used the orthogonal distance regression technique. The new relations are IMCS = 1.68 ± 0.22 + 2.58 ± 0.14 log P GA, σ = 0.35 and IMCS = 5.11 ± 0.07 + 2.35 ± 0.09 log P GV , σ = 0.26. Tests designed to assess the robustness of the estimated coefficients have shown that single-line parameterizations for the regression are sufficient to model the data within the model uncertainties. The relations have been inserted in the Italian implementation of the USGS-ShakeMap to determine intensity maps from instrumental data and to determine PGM maps from the sole intensity values. Comparisons carried out for earthquakes where both kinds of data are available have shown the general effectiveness of the relations

ShakeMap implementation in Italy

Since 2005, the Italian Civil Protection (Dipartimento della Protezione Cilvile, DPC) has funded several projects driven toward fast assessment of ground motion shaking in Italy - the final goal being that of organizing the emergency and direct the search and rescue (SAR) teams. To this end, the Istituto Nazionale di Geofisica e Vulcanologia (INGV) has started to determine shakemaps using the USGS-ShakeMap package within 30 minutes from event occurrence and adopting a manually revised location. In this paper we present the INGV implementation of USGS-ShakeMap for earthquakes occurring in Italy and immediately neighboring areas. Emphasis is put on data acquisition, the adopted ground motion predictive relations and the site corrections for the local amplifications of the ground motion. Finally, two examples of shakemaps are shown - the first determined for a recent medium size earthquake, the other for the large Irpinia, 1980, M6.9 event. For both events, the maps are compared to the available macroseismic data

Training Prospective Primary and Kindergarten Teachers on Electric Circuits Using Conceptual Metaphors

The awareness and use of conceptual metaphors available in ordinary language should be a relevant part of teaching strategies, yet it is still rather neglected in teacher education. With a specific activity, we integrated a class of prospective kindergarten and primary school teachers on electric circuits with a reflection on the cognitive and linguistic aspects of metaphor. To understand how effective this integration proved to be, both in terms of learning and in terms of developing teaching skills, we conducted a single case study with a mixed qualitative–quantitative methodol-ogy. Student teachers were invited to analyze and discuss expressions on electric circuits selected from those they themselves had formulated at an earlier time. Here, we present some relevant results from the analysis of the students’ elaborations, highlighting how they worked with metaphors. They demonstrated a better understanding of the subject matter and greater awareness of teaching as well, in particular for what concerns the use of language and identifying and overcoming implicit ideas

Thermal sensors interfaced with computer as extension of senses in Kindergarten and Primary School

New technologies offer new learning opportunities for teaching science also in primary. Simple experimental situations based on on-line sensors are proposed for interactive activities as a powerful extension of senses. In particular they can allow a phenomenological exploration of thermal processes based on a thermodynamic approach. The exploration of thermal properties by tactile sensation is widened by the use of on-line sensors. In the proposed didactical approach, pupils correlate the processes they realize with the real time graphs they observe, activating imaginative reduction of the concepts under study

An interview with Marisa Michelini: IUPAP-ICPE medal, professor of physicseducation research at Udine University, GIREP President

The present interview was conceived and realized for the occasion of the first 45 years of endless Physics Education Research activity of Professor Marisa Michelini, a lifetime dedicated to innovate teaching and learning environments to all degrees of instruction, and to design institutional architectures, where rooting these innovations. The interview structure is inspired to the nature of scientific thinking, i.e. inducing more general understanding from concrete observations, in two manners. First, the interview focuses on (ten) topics drawing from three box-cases about physics education research and teachers education in scientific areas: innovations in teaching/learning environments; theoretical and methodological frameworks; and strategies and tools for institutional cooperation between schools and governing bodies to urge policy making. Each topic is introduced by observations, from which the interview questions are induced. Second, each question draws from Marisa Michelini’s contributions, to touch core topics at the heart of science education, science and society

Gamma ray detection: building a didactic proposal

A simple and economic scintillator kit in combination with a computer-based oscilloscope was used to develop a learning experience, comprised of a set of activities to introduce students in an interactive way to the physics of gamma-ray detection. The proposal for secondary school and university students is built by means of frequent on-the-fly formative assessment to collect difficulties of students and ways to overcome them. Internal decays of Lutetium-yttrium oxyorthosilicate (LYSO) crystals already present in the scintillator kit are used as sources of gamma rays, so no external sources were needed. In addition, the use of LYSO crystals offers a reason to discuss coincidence measurements, because of the inherent beta background present in the internal decay, which can be at least partially removed with coincidence measurements. The goal of the learning experience is to experience how gamma-ray detection is actually done, discussing the physics involved, motivated by the current frontline research on the detection of gamma-ray bursts