From the double-stranded helix to the chiral nematic phase of B-DNA: a molecular model

B-DNA solutions of suitable concentration form left-handed chiral nematic phases (cholesterics). Such phases have also been observed in solutions of other stiff or semiflexible chiral polymers; magnitude and handedness of the cholesteric pitch are uniquely related to the molecular features. In this work we present a theoretical method and a numerical procedure which, starting from the structure of polyelectrolytes, lead to the prediction of the cholesteric pitch. Molecular expressions for the free energy of the system are obtained on the basis of steric and electrostatic interactions between polymers; the former are described in terms of excluded volume, while a mean field approximation is used for the latter. Calculations have been performed for 130 bp fragments of B-DNA. The theoretical predictions provide an explanation for the experimental behavior, by showing the counteracting role played by shape and charge chirality of the molecule.Comment: 42 pages, 6 figure

Teaching and learning color. An insight into STEM/STEAM approach

The paper aims to help define the STEM/STEAM approach to Color Education. Nowadays more and more schools embrace this approach as it seems to respond to a need for renewal of teaching while adapting it to the present time. However, this approach is not univocally defined, so that under this label fall experiences of color education of various kinds and different educational effectiveness. Therefore, this work intends to clarify the meaning of this approach. The article is divided into three parts that show the methodological path undertaken. In the first part, some invariant properties of situations classified as STEM/STEAM were identified; in the second part, the invariants were described in terms of didactic variables inferred from the literature and some STEM/STEAM teaching activities; in the third part, some procedural principles to guide teachers' work were formulated and discussed in the context of teaching and learning about color

Torsion pendulum facility for direct force measurements of LISA GRS related disturbances

A four mass torsion pendulum facility for testing of the LISA GRS is under development in Trento. With a LISA-like test mass suspended off-axis with respect to the pendulum fiber, the facility allows for a direct measurement of surface force disturbances arising in the GRS. We present here results with a prototype pendulum integrated with very large-gap sensors, which allows an estimate of the intrinsic pendulum noise floor in the absence of sensor related force noise. The apparatus has shown a torque noise near to its mechanical thermal noise limit, and would allow to place upper limits on GRS related disturbances with a best sensitivity of 300 fN/Hz^(1/2) at 1mHz, a factor 50 from the LISA goal. Also, we discuss the characterization of the gravity gradient noise, one environmental noise source that could limit the apparatus performances, and report on the status of development of the facility.Comment: Submitted to Proceedings of the 6th International LISA Symposium, AIP Conference Proceedings 200

Promuovere la competenza epistemica attraverso l’educazione scientifica. Il ruolo della storia della scienza e dell’epistemologia nella formazione degli insegnanti

In a knowledge-intensive society where science and technology play a significant role, easy access to information due to user-friendly devices increases the risk of forming erroneous beliefs that encourage potentially dangerous behavior. Thus, the task of school is to educate epistemically competent citizens who know how to act responsibly within the information ecosystems in which we live. In this paper, we intend to show how a didactic transposition of the scientific disciplines, aimed at also bringing out their 'syntax', helps to achieve this educational objective. To this end, we propose two didactic tools for teacher training, conceived in such a way as to structurally integrate the contributions that epistemology and the history of science can provide to the clarification and solution of didactic problems related to its syntactic structure

COOPERATION AND INTERNATIONALIZATION EXPERIENCE WITHIN HIGHER EDUCATION

Education has historically developed parallel to socio-technological changes; at present the innovations in information and communication technologies promote a new educational paradigm, where the search for higher education quality, pertinence and internationalization is remarkable On these lines, the creation of university networks of postgraduate studies, students and researchers mobility and the cooperation of Spanish American researchers who work outside the region constitute one of the goals which Ibero American countries aim at achieving during the next decade (OEI, 2010). Within this context, the aim of this paper is to describe an experience of cooperation and internationalization with teachers and postgraduate students mobility which took place in the Departamento de Economía de la Universidad Nacional del Sur (Department of Economics of National University of the South). This experience took place from 2008 to 2011 in the context of the Programa de Centros Asociados para el Fortaleciomiento de Posgrados, Proyecto CAFP (Program of Associate Centers for the Strengthening of Postgraduate Studies, CAFP Project) and the promoting institution was the Departamento de Desemvolvimento, Agricultura e Sociedade and Instituto de Ciencias Humanas e Sociais (CPDA) of the Universidades Federal Rural do Rio de Janeiro and the receiving institution, the Departamento de Economía of UNS (Department of Economics of the National University of the South). Thus, two postgraduate programs were linked: The Program of Pós Graduacáo de Ciencias Sociais em Desemvolvimento, Agricultura e Sociedades del CPDA and the Magister in Agrarian and Rural Management of UNS. Based on the weaknesses of the latter, the proposed objectives were, among others, improving the graduation rate, revising and updating the Course of Studies, widening the research lines and incorporating interdisciplinary approaches

COOPERATION AND INTERNATIONALIZATION EXPERIENCE WITHIN HIGHER EDUCATION

Education has historically developed parallel to socio-technological changes; at present the innovations in information and communication technologies promote a new educational paradigm, where the search for higher education quality, pertinence and internationalization is remarkable On these lines, the creation of university networks of postgraduate studies, students and researchers mobility and the cooperation of Spanish American researchers who work outside the region constitute one of the goals which Ibero American countries aim at achieving during the next decade (OEI, 2010). Within this context, the aim of this paper is to describe an experience of cooperation and internationalization with teachers and postgraduate students mobility which took place in the Departamento de Economía de la Universidad Nacional del Sur (Department of Economics of National University of the South). This experience took place from 2008 to 2011 in the context of the Programa de Centros Asociados para el Fortaleciomiento de Posgrados, Proyecto CAFP (Program of Associate Centers for the Strengthening of Postgraduate Studies, CAFP Project) and the promoting institution was the Departamento de Desemvolvimento, Agricultura e Sociedade and Instituto de Ciencias Humanas e Sociais (CPDA) of the Universidades Federal Rural do Rio de Janeiro and the receiving institution, the Departamento de Economía of UNS (Department of Economics of the National University of the South). Thus, two postgraduate programs were linked: The Program of Pós Graduacáo de Ciencias Sociais em Desemvolvimento, Agricultura e Sociedades del CPDA and the Magister in Agrarian and Rural Management of UNS. Based on the weaknesses of the latter, the proposed objectives were, among others, improving the graduation rate, revising and updating the Course of Studies, widening the research lines and incorporating interdisciplinary approaches

una rilettura dell insegnamento della geometria in prospettiva husserliana

Il contributo si propone di discutere il rapporto tra saperi formali "a statuto forte" e saperi della pratica nelle sue implicazioni epistemologiche e didattiche, alla luce delle analisi husserliane sull'origine della geometria. A tale scopo, si e scelto come dispositivo metodologico la nozione husserliana di "analisi genetica", in quanto ci consente di problematizzare in senso dinamico la relazione teoria/prassi in ambito geometrico. In particolare, Tale dispositivo consente, infatti, di interpretare i concetti ideali della geometria come correlati di operazioni idealizzanti che, innestandosi su operazioni concretamente praticabili e descrivibili, forniscono un ancoraggio all'apprendimento in quanto consentono di saldare il pensiero all'esperienza. Piu in generale, tale costrutto, si rivela un valido dispositivo didattico, nell'ambito dell'educazione scientifica e non solo, per l'identificazione di processi significativi di "genesi artificiale" del sapere. Il contributo apre a nuove direzioni di ricerca teorica ed empirica sull'applicazione della nozione di "analisi genetica" alle differenti discipline d'insegnamento

La dialettica generale/specifico alla luce del costrutto didattico di ostacolo epistemologico

This work proposes the epistemological obstacle as a teaching device focusedon knowledge, whose aim is to link general and specific aspects ofthe cognitive process. In particular, the construct captures the intentionalcharacter of knowledge by problematizing the relationship between theepistemic practices of the subject and the object of knowledge that is constitutedthrough them. In the first part the problem is presented from anepistemological and a didactic standpoint. Then the theoretical work hypothesesare formulated. Finally we discuss about the didactic role assumedby the concept of epistemological obstacle in the relationship betweennaive and expert physics. This paper opens up new directions of empiricalresearch regarding the application of the concept of epistemological obstacleto the different teaching disciplines.Il contributo propone l’ostacolo epistemologico come dispositivo didatticofocalizzato sul sapere, finalizzato a coniugare aspetti generali e aspetti specificidel processo conoscitivo. In particolare, il costrutto coglie il carattere intenzionaledella conoscenza problematizzando il rapporto tra le prassi epistemichedel soggetto e l’oggetto di sapere che attraverso di esse si costituisce.Nella prima parte si presenta il problema da un punto di vista epistemologicoe didattico. Successivamente si formulano le ipotesi teoriche di lavoro.Infine si discute il ruolo didattico che il concetto di ostacolo epistemologicoassume nel rapporto tra fisica ingenua e fisica esperta. Il contributoapre a nuove direzioni di ricerca empirica sull’applicazione del concetto diostacolo epistemologico alle diverse discipline d’insegnamento

L’uso di modelli simulativi per la costruzione del pensiero controfattuale in contesti formativi

In this paper we discuss the potential effectiveness of the use of simulation models for the construction of counterfactual thought in training contexts. Counterfactual mental experiments represent an epistemic practice which belongs to the scientist’s habitus. Therefore, it is important for students to acquire it. In the first part the role of counterfactual mental experiments is presented from an epistemological standpoint. Then counterfactual reasoning is described as an epistemological obstacle. Finally, we explore the didactic potentialities of simulation models in fostering the development of counterfactual thought.Nel contributo si discute la potenziale efficacia dell’impiego di modelli simulativi per la costruzione del pensiero controfattuale in contesti formativi. Gli esperimenti mentali controfattuali rappresentano una pratica epistemica che appartiene all’habitus dello scienziato ed è quindi importante che gli studenti la acquisiscano. Nella prima parte si chiarisce il ruolo degli esperimentimentali controfattuali da un punto di vista epistemologico. Successivamente si attribuisce al ragionamento controfattuale lo status di ostacolo epistemologico. Infine, si esplorano le potenzialità didattiche dei modelli simulativi nel promuovere lo sviluppo del pensiero controfattuale