Aspects of SU(N_c) Gauge Theories in the Limit of Small Number of Colors

We investigate properties of the color space of $SU(N_c)$ gauge theories in the limit of small number of colors $(N_c \to 0)$ and large number of flavors. More generally, we introduce a rescaling of $\alpha_s$ and $n_f$ which assigns a finite limit to colored quantities as $N_c \to 0$, which reproduces their known large-$N_c$ limit, and which expresses them as an analytic function of $N_c^2$ for arbitrary value of $N_c$. The vanishing-$N_c$ limit has an Abelian character and is also the small-$N_c$ limit of $[U(1)]^{N_c-1}$. This limit does not have an obvious quantum field theory interpretation; however, it provides practical consistency checks on QCD perturbative quantities by comparing them to their QED counterparts. Our analysis also describes the two-dimensional topological structure involved in the interpretation of the small $N_c$-limit in color space.Comment: Contract number added, LaTex, 16 page

Turning engineers into reflective university teachers

Increasing attention to quality and innovation in Higher Education (HE) is enhancing the pedagogic knowledge of faculty members and thereby encouraging the academic success of their students. This aim requires, from the institution and teachers, a greater degree of involvement than was previously the case. This is certainly borne out by experience in Portuguese universities. The growing concern of engineers with issues of pedagogy and academic success marks a sea change in the traditional conceptions of teaching and learning in Higher Education. There are, of course, indications that many academics are resistant to change. Our research indicates a tradition among Portuguese and Scottish academics to incline their effort toward research with a resultant decline in interest and effort on teaching. The present paper presents a meta-analysis of research conducted at the University of Aveiro (Portugal) and the University of Strathclyde (United Kingdom) between 2000 and 2004 involving academics who taught first-year introductory Programming courses. The purpose of our study was to promote reflection and research on teaching based issues as a strategy toward improved student learning. The findings of the study raised a number of salient issues for discussion and consideration. In this paper, we present some of these issues, aiming to explore the impact that the findings may have on teachers' attitudes towards teaching and students' learning in introductory programming courses

Insights on best teaching practices for promoting students' learning

The Department of Educational Sciences and the Department of Electronic and Telecommunications at the University of Aveiro (Portugal) have been working together with the Department of Computer and Information Sciences at the University of Strathclyde (UK), with the aim of improving the teaching and learning of introductory programming courses. Both institutions belong to the European Consortium of Innovative Universities (ECIU), with a commitment to "developing and implementing new forms of teaching, training, and research; to assuring an innovative culture within their walls; to experimenting with new forms of management and administration; and to sustaining and nurturing internationally-minded staff" (ECIU). Over the past two years, data has been collected through interviews, questionnaires and class observation, to better understand the organization of the different courses and approaches to teaching and learning. Members of academic staff have been actively involved in trying to enhance the students' learning experience through reflection on teaching methods and trying new ideas to aid student success. During this process we have assimilated insights on teaching philosophies, methods and suggestions for course redesign. As an important piece of the "puzzle", students also provided useful feedback on differing aspects of teaching and course organization. The present paper presents a meta-analysis of our findings on the relevance of teaching practices for promoting students' learning. In addition, we discuss the impact that teaching philosophies and course organization may have on best teaching practices

Quality Assurance System to monitor the teaching and learning process at the University of Aveiro (Portugal)

At the University of Aveiro (UA), in Portugal, institutional initiatives are being undertaken so that high levels of quality teaching and learning are achieved. This paper presents (a) the design of an evaluation model for quality assurance of teaching and learning and (b) the results of its application in a pilot study that ran in 2008/09 at the Departments of Electronics and Telecommunications, and Physics, of the UA. The Quality Assurance System (QAS) to monitor the process of teaching and learning at the UA emerges as extremely important, not only to regulate the teaching and learning process, following the quality assurance orientations at a national and international level, but also to reflect and share teaching practices that enhance the whole academic experience, both from students, teachers, and researchers‟ perspectives. The authors explore the design of the model and some findings of the pilot study, more specifically the identification of problematic and good practice situations identified by the students‟ survey and reports

Isotope shifts and hyperfine structure of the Fe I 372 nm resonance line

We report measurements of the isotope shifts of the $3d^64s^2 a ^5D_4 - 3d^64s4p z ^5F_5^o$ Fe I resonance line at 372 nm between all four stable isotopes $^{54}$Fe, $^{56}$Fe, $^{57}$Fe, and $^{58}$Fe, as well as the complete hyperfine structure of that line for $^{57}$Fe, the only stable isotope having a non-zero nuclear spin. The field and specific mass shift coefficients of the transition have been derived from the data, as well as the experimental value for the hyperfine structure magnetic dipole coupling constant $A$ of the excited state of the transition in $^{57}$Fe: $A(3d^64s4p z ^5F_5^o) = 81.69(86)$ MHz. The measurements were done by means of Doppler-free laser saturated-absorption spectroscopy in a Fe-Ar hollow cathode using both natural and enriched iron samples. The measured isotope shifts and hyperfine constants are reported with uncertainties at the percent level.Comment: 5 pages, 5 figure

Symbolic Algorithms for Language Equivalence and Kleene Algebra with Tests

We first propose algorithms for checking language equivalence of finite automata over a large alphabet. We use symbolic automata, where the transition function is compactly represented using a (multi-terminal) binary decision diagrams (BDD). The key idea consists in computing a bisimulation by exploring reachable pairs symbolically, so as to avoid redundancies. This idea can be combined with already existing optimisations, and we show in particular a nice integration with the disjoint sets forest data-structure from Hopcroft and Karp's standard algorithm. Then we consider Kleene algebra with tests (KAT), an algebraic theory that can be used for verification in various domains ranging from compiler optimisation to network programming analysis. This theory is decidable by reduction to language equivalence of automata on guarded strings, a particular kind of automata that have exponentially large alphabets. We propose several methods allowing to construct symbolic automata out of KAT expressions, based either on Brzozowski's derivatives or standard automata constructions. All in all, this results in efficient algorithms for deciding equivalence of KAT expressions

Linking educational research to institutional measures of quality enhancement: a Portuguese project

At the University of Aveiro (UA), an institutional initiative is taking place for assessing and monitoring the quality of teaching and learning in Higher Education. The Quality Assurance System (QAS) of the teaching and learning process at the UA emerges as extremely important, not only to regulate the teaching and learning process, following the quality assurance orientations at a national and international level, but also to reflect and share teaching practices that enhance the whole academic experience, both from the students, the teachers, and researchers’ perspective. The authors explore the design of the model and a research study that aims to integrate the perspectives of students and teachers, through the analysis of quantitative and qualitative data - gathered in the evaluation model, so that: (i) intervention strategies/activities can be conceptualised for coping with the identified problems; (ii) a set of guidelines can be designed for the improvement of the evaluation model and associated instruments, and (iii) the QAS model and its results can be discussed with academia in terms of strengths and weaknesses aiming to engage them in the process of monitoring. This study is an effort to conciliate the educational research carried out by members of the Laboratory for the Evaluation of Educational Quality and the institutional framework for quality assurance