Role of inflexible minorities in the evolution of alcohol consumption

In this work we study a simple mathematical model for drinking behavior evolution. For this purpose, we considered three compartments, namely Susceptible individuals $S$ (nonconsumers), Moderated drinkers $M$ and Risk drinkers $R$. Inside the $S$ and $R$ compartments, we considered the presence of inflexible or zealot agents, i.e., individuals that never change their behavior (never drink or always drink a lot). These inflexible agents are described by fixed densities $s_I$ and $r_I$, for nonconsumer inflexible and risk drinking inflexible individuals, respectively. We analyze the impact of the presence of such special agents in the evolution of drinking behavior in the population. Specifically, since the presence of inflexible agents are similar to the introduction of quenched disorder in the model, we are interested in the impact of such disorder in the critical behavior of the system. Our analytical and numerical results indicate that the presence of only one class of inflexible agents, $s_I$ or $r_I$, destroys one of the two possible absorbing phases that are observed in the model without such inflexibles, i.e., for $s_i=r_I=0$. In the presence of the both kinds of inflexible agents simultaneously, there are no absorbing states anymore. Since absorbing states are collective macroscopic states with the presence of only one kind of individuals in the population, nonconsumers or risk drinkers, we argue that the inclusion of inflexible agents in the population makes the model more realistic. In addition, the work makes a contribution to studies on the impact of quenched disorder in nonequilibrium phase transitions, that are a subject of interest for Nonequilibrium Statistical Physics.Comment: 19 pages, 7 figures, submitted for publicatio

Learning practices through recursive questionnaires

Distance education or distance learning (DL) in undergraduate courses is growing considerably in the last decades (Holmes & Reid, 2017) and got even more attention due to the COVID pandemic (Crawford et al., 2020; Baggaley, 2020). Students pursuing distance learning have often suffered from isolation and lack of a learning community, resulting in high dropout rates. In general, students’ engagement depends strongly on the evaluation methods (Holmes, 2018), and they define how students manage their time in study. Introduction to Physical Sciences 1 (ICF1) is the subject in which this work was developed in a DL course with over 1500 students per semester at CEDERJ (Distance Education Center of the State of Rio de Janeiro). In this work, we modified the method of evaluation of two optional assessments (OA) that was given to the students, whose main goal is to promote the practice, through exercises, of two fundamental contents in physics which students often have doubts and misconceptions from high school: vectors (OA1) and Newton's laws (OA2). This modification was carried out by implementing a recursive formative online assessment that students can answer as many times as they want until a specified due date. The assessment avoids memorizing the answers to the questions by generating new numerical values for each question and randomly mixing their order in every new attempt. After finishing the questionnaire, students receive immediate feedback to correct their mistakes and try to achieve a better score, in such a way that mistakes can be beneficially used as part of their learning process. Each attempt is recorded and all students’ progress is analyzed using a computational Python code. With this approach, the professor can identify and eventually interact with students who need a higher level of attention before the final exams. The former OAs were not clearly evaluating the students and helping them to better understand the required subjects. In the old format, comparisons and copying of questions could be used by the students in such a way that created an illusory impression on them that they were understanding the underlying concepts. Thus, there was a lack of correlation between the scores in the OAs and the final scores of the students. Our analysis after the implementation of the recursive questionnaires, shows that students with high scores in the OA have more chances to pass the course, as expected from an exam that correctly evaluates the students’ performance. This methodology is a valuable asset for the students’ learning process, regardless of whether they are in a DL course or a regular face-to-face course, and for the professors to identify patterns that can foresee students’ difficulties with their learning progress, allowing to address specific students in need even in classes with a large number of students. REFERENCES Baggaley, J. (2020). Educational distancing. Distance Education, 41(4), 582-588. https://doi.org/10.1080/01587919.2020.1821609 Crawford, J., Butler-Henderson, K., Rudolph, J., Malkawi, B., Glowatz, M., Burton, R., Magni, P., & Lam, S. (2020). COVID-19: 20 countries' higher education intra-period digital pedagogy responses. Journal of Applied Learning & Teaching, 3(1), 1-20. http://dx.doi.org/10.37074/jalt.2020.3.1.7 Holmes, C. M. & Reid, C. (2017). A comparison study of on-campus and online learning outcomes for a research methods course. The Journal of Counselor Preparation and Supervision, 9(2), 15. http://dx.doi.org/ 10.7729/92.1182 Holmes, N. (2018). Engaging with assessment: Increasing student engagement through continuous assessment. Active Learning in Higher Education, 19(1), 23-34. https://doi.org/10.1177/146978741772323

Recent insights into antioxidant defenses of legume root nodules

43 Pag., 2 Tabl., 2 Fig. The definitive version is available at: www3.interscience.wiley.comLegume root nodules are sites of intense biochemical activity and consequently are at high risk of damage as a result of the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These molecules can potentially give rise to oxidative and nitrosative damage but, when their concentrations are tightly controlled by antioxidant enzymes and metabolites, they also play positive roles as critical components of signal transduction cascades during nodule development and stress. Thus, recent advances in our understanding of ascorbate and (homo)glutathione biosynthesis in plants have opened up the possibility of enhancing N2 fixation through an increase of their concentrations in nodules. It is now evident that antioxidant proteins other than the ascorbate-glutathione enzymes, such as some isoforms of glutathione peroxidases, thioredoxins, peroxiredoxins, and glutathione S-transferases, are also critical for nodule activity. To avoid cellular damage, nodules are endowed with several mechanisms for sequestration of Fenton-active metals (nicotianamine, phytochelatins, and metallothioneins) and for controlling ROS/RNS bioactivity (hemoglobins). The use of ‘omic’ technologies has expanded the list of known antioxidants in plants and nodules that participate in ROS/RNS/antioxidant signaling networks, although aspects of developmental variation and subcellular localization of these networks remain to be elucidated. To this end, a critical point will be to define the transcriptional and post-transcriptional regulation of antioxidant proteins.The research described here was supported by a grant from the National Science Foundation (IOS-0517688) to D.A.D., and a grant from the Spanish Ministry of Science and Innovation-FEDER (AGL2008-01298) and Government of Aragón (group A53) to M.B.Peer reviewe