Canonical Field Anticommutators in the Extended Gauged Rarita-Schwinger Theory

We reexamine canonical quantization of the gauged Rarita-Schwinger theory using the extended theory, incorporating a dimension $\frac{1}{2}$ auxiliary spin-$\frac{1}{2}$ field $\Lambda$, in which there is an exact off-shell gauge invariance. In $\Lambda=0$ gauge, which reduces to the original unextended theory, our results agree with those found by Johnson and Sudarshan, and later verified by Velo and Zwanziger, which give a canonical Rarita-Schwinger field Dirac bracket that is singular for small gauge fields. In gauge covariant radiation gauge, the Dirac bracket of the Rarita-Schwinger fields is nonsingular, but does not correspond to a positive semi-definite anticommutator, and the Dirac bracket of the auxiliary fields has a singularity of the same form as found in the unextended theory. These results indicate that gauged Rarita-Schwinger theory is somewhat pathological, and cannot be canonically quantized within a conventional positive semi-definite metric Hilbert space. We leave open the questions of whether consistent quantizations can be achieved by using an indefinite metric Hilbert space, by path integral methods, or by appropriate couplings to conventional dimension $\frac{3}{2}$ spin-$\frac{1}{2}$ fields.Comment: Latex, 17 page

Effect of the Gribov horizon on the Polyakov loop and vice versa

We consider finite temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger (GZ) quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanziger quantization procedure in order to illustrate the approach and the potential direct link between the vacuum structure of the theory (dynamical mass scales) and (de)confinement. We also present a first look at the critical temperature obtained from the Refined Gribov-Zwanziger approach. Finally, a particular problem for the pressure at low temperatures is reported.Comment: 19 pages, 8 .pdf figures. v2: extended section 3 + extra references; version accepted for publication in EPJ

Correction of artificial jumps in the historical geomagnetic measurements of Coimbra Observatory, Portugal

The Coimbra Magnetic Observatory (International Association of Geomagnetism and Aeronomy code COI) in Portugal has a long history of observation of the geomagnetic field, spanning almost 150 yr since the first geomagnetic measurements in 1866. These long instrumental geomagnetic records provide very important information about variability of geomagnetic elements and indices, their trends and cycles, and can be used to improve our knowledge on the sources that drive variations of the geomagnetic field: liquid core dynamics (internal) and solar forcing (external). <br><br> However, during the long life of the Coimbra Observatory, some inevitable changes in station location, instrument's park and electromagnetic environment have taken place. These changes affected the quality of the data collected at COI causing breaks and jumps in the series of geomagnetic field components and local K index. Clearly, these inhomogeneities, typically shift-like (step-like) or trend-like, have to be corrected or, at least, minimized in order for the data to be used in scientific studies or to be submitted to international databases. <br><br> In this study, the series of local K index and declination of the geomagnetic field are analysed: the former because it allows direct application of standard homogenization methods and the latter because it is the longest continuous series produced at COI. For the homogenization, visual and statistical tests (e.g. standard normal homogeneity test) have been applied directly to the local geomagnetic K index series (from 1951 to 2012). The homogenization of the monthly averages of declination (from 1867 to 2012) has been done using visual analysis and statistical tests applied to the time series of the first differences of declination values, as an approximation to the first time derivative. This allowed not only estimating the level of inhomogeneity of the studied series but also detecting the highly probable homogeneity break points. These points have been cross-checked with the metadata, and the COI series have been compared with reference series from the nearest geomagnetic stations and, in the case of declination series, from the recent geomagnetic field model COV-OBS to set up the required correction factors. As a result, the homogenized series measured in COI are considered to be essentially free of artificial shifts starting from the second half of the 20th century, and ready to be used by the scientific community

Assessing students' engagement levels during lockdown: a survey in tourism degrees

In early 2020, the crisis of a new virus and a pandemic context took the world by storm. All sectors of society were affected: health, economics,… and education was no exception, with all levels suspending face-to-face classes, which were replaced by online activities. In view of this situation, several doubts and uncertainties emerged among educators, but one question stood out: how to proceed with teaching activities in the online format without compromising the commitment and engagement of the students? Within this context, the teachers involved in this study sought to adapt the activities and teaching materials to the exclusive use of technology and promoted asynchronous tasks, which could be developed independently by the students. In order to understand how the profound changes in Higher Education were experienced by students, a quantitative survey was conducted. The participants in the study are undergraduate students from a Portuguese Higher Education institution attending the curricular units of Statistical Analysis and English.info:eu-repo/semantics/publishedVersio

Student receptiveness to Kahoot! in higher education

The use of technology in higher education has been increasing in the past few years and new online tools have emerged for very different purposes. Kahoot! is an example of a platform that can be used for reviewing content and motivating students for learning. Our research is based on data from a quantitative survey conducted in the previous school year and the participants were 86 undergraduate students from a Portuguese higher education institution. The preliminary results of the survey showed that students are very receptive to this tool and highly recommend it, as it promotes motivation. Other studies have shown that higher education students are usually receptive to web tools and consider technology can positively impact learning. To better understand students’ responses to the platform, in this study we aim at analysing the results according to area of study and investigating new correlations between variables, specifically (i) gender vs receptiveness to Kahoot!, (ii) gender vs recommendation of its use and (iii) technology readiness vs receptiveness to Kahoot!.info:eu-repo/semantics/publishedVersio

The importance of hope for quality of life in patients with multiple sclerosis

Aims: This study intends to describe the importance of hope for the quality of life in patients with multiple sclerosis. Evidence has indicated that Hope is important as a buffer between risk factors, physical and psychological health status, and quality of life for patients with multiple sclerosis. Methods: The study was exploratory and descriptive. Setting: A general Hospital in Lisbon, Portugal. Participants: 280 patients with Multiple Sclerosis. We explore the relationship between Hope and Quality of Life. The instruments used are the Multiple Sclerosis Quality of Life scale (MSQol-54) and the Hope Scale. Results: The correlation between the Hope Scale and the domains of MSQOL-54: Physical Health (r=0.24, p<0.05), Physical Role Limitations (r=0.25, p<0.05), Emotional Role Limitations (r=0.35, p<0.05), Pain (r=0.28, p<0.05),Well-being (r=0.48, p<0.01), Energy (r=0.42, p<0.01), Health in General (r=0.41, p<0.01), Social Function (r=0.45, p<0.01), Cognitive Function (r=0.28, p<0.05), Health Distress (r=0.52, p<0.01), Overal Qol (r=0.49, p<0.01), Sexual function (r=0.33, p<0.05), Change in Health (r=-0.17, p<0.05), and Satisfaction with sexual function (r=0.33, p<0.05). Conclusions: There is a statistically significant correlation between the variables, suggesting that hope can play an important role in the quality of life of patients with multiple sclerosis, especially in domains such as the perception of well-being, health in general, and social function, and distress.info:eu-repo/semantics/publishedVersio

Kahoot! and socrative in higher education: a comparative study

Technology brings new challenges and opportunities to higher education institutions, as it can promote learner-centered activities. Mobile devices such as smartphones are very popular among students and can easily engage them and promote motivation and active learning. In this study, we investigate Tourism undergraduate students’ perceptions on the use of mobile technology in the classroom, specifically two quiz makers in a comparative perspective: Kahoot! and Socrative. The purpose of this two-stage study is to identify and meet students’ preferences, so as to design activities that can truly promote learning. The participants are Mathematics and English students from a Portuguese higher education institution. At the first stage, in a preliminary survey, 33 students have identified their quiz preferences and most of them (87,88%) selected Socrative as their favourite quiz maker. At the second stage, students were also inquired about their general perceptions and preferred features, such as collaborative mode, competition mode, self-paced mode or immediate feedback. Similar studies have shown that these tools can promote engagement, motivation, concentration and learning. Therefore, we hope to contribute to a better understanding of how technology can improve the learning process.info:eu-repo/semantics/publishedVersio