Adaptation of the AcubeSAT nanosatellite project into remote working during the COVID-19 era

The global COVID-19 pandemic has undoubtedly forced the global community to embrace the transition to a world where remote and hybrid work models are becoming the new standard. But for the space engineering community, this change is more impactful than other engineering fields. Switching the entire workload from in-person concurrent design and verification activities to a hybrid or an online model has dominated the discussions in relevant symposia since the start of the pandemic. This switch is also more challenging when you must accommodate more than 50 developers who are volunteer students. The AcubeSAT team underwent this transition during 2020-2021, where all design and pro- totyping activities for the team’s nanosatellite were moved to a remote work scheme. After several adaptations, this scheme has been fine-tuned and experimented upon to ensure that development activities could continue at a normal pace, and that the physical and mental health of the entire team was guaranteed. These adaptations include changes in infrastructure, team structure and meetings, but most notably they attempt to answer the question of how the concurrent design technique and the review processes can be implemented in an online world. More specifically, a number of ready-made and in-house platforms and utilities, mostly based on the open-source philosophy, were used to bridge the gap between in-person and on-line workloads. In an attempt to combine the advantages of online conferencing with the casualness, directness and availability of in-person meetings, we analysed and experimented with various online platforms and project management tools to foster organic collaboration. Furthermore, the use of version control systems as a main tool for internal and external reviews and the documentation produced by the team allowed for a more transparent, reliable and streamlined review process. All of these changes enabled the conclusion of AcubeSAT’s Critical Design Review remotely in summer 2021. The project is now in the manufacturing and verification phase, with the hybrid work model still in place. With this contribution, lessons learned from the project’s transition to an online and subsequently to a hybrid work scheme will be shared, showing how a large-scale educational project can be implemented under these conditions. The changes performed to accommodate this scheme, along with the rationale behind them and the subsequent challenges posed by them, will also be discussed. Finally, the benefits of such a transition will also be presented, which include more efficient use of time, superior project documentation and the enlargement of the project to students from international universities

Agile Systems Engineering for sub-CubeSat scale spacecraft

Space systems miniaturization has been increasingly popular for the past decades, with over 1600 CubeSats and 300 sub-CubeSat sized spacecraft estimated to have been launched since 1998. This trend towards decreasing size enables the execution of unprecedented missions in terms of quantity, cost and development time, allowing for massively distributed satellite networks, and rapid prototyping of space equipment. Pocket-sized spacecraft can be designed in-house in less than a year and can reach weights of less than 10g, reducing the considerable effort typically associated with orbital flight. However, while Systems Engineering methodologies have been proposed for missions down to CubeSat size, there is still a gap regarding design approaches for picosatellites and smaller spacecraft, which can exploit their potential for iterative and accelerated development. In this paper, we propose a Systems Engineering methodology that abstains from the classic waterfall-like approach in favor of agile practices, focusing on available capabilities, delivery of features and design "sprints". Our method, originating from the software engineering disciplines, allows quick adaptation to imposed constraints, changes to requirements and unexpected events (e.g. chip shortages or delays), by making the design flexible to well-defined modifications. Two femtosatellite missions, currently under development and due to be launched in 2023, are used as case studies for our approach, showing how miniature spacecraft can be designed, developed and qualified from scratch in 6 months or less. We claim that the proposed method can simultaneously increase confidence in the design and decrease turnaround time for extremely small satellites, allowing unprecedented missions to take shape without the overhead traditionally associated with sending cutting-edge hardware to space

Evaluación de aceitunas negras estilo griego utilizando salmueras de diferentes concentraciones

hree fermentation processes with black table-olives were tested. Olives were placed in: a) 16 %(w/v) concentration of NaCl, (traditional treatment), b) a buffer of CH3COOH (0.05M) and Ca(OH)2, (0.025M) without any NaCl and initial pH 4.7, and c) a buffer of CH3COOH (0.05M) and Ca(OH)2 (0.025M) containing 12.8 % (w/v) NaCl, and pH 4.3. Isolation, identification and enumeration of predominant microorganisms from fruits and brines sampled during the fermentation periods as well as color, intensity, texture and sensory evaluation tests of the final products were conducted. The third fermentation process, (c), yielded a product with low salt content no presence of spoilage microflora or other alterations during the fermentation period, with significantly better final texture and color, and higher acceptability among the consumers (PSe han ensayado tres procesos para la elaboración de aceitunas negras de mesa. Los frutos se colocaron en: a) una salmuera con una concentración de sal del 16 % (w/w), proceso tradicional; b) en una solución tampón compuesta de CH3COOH (0.05M) y Ca(OH)2 (0.025M) , sin NaCl y con un pH inicial de 4.3; c) una solución tampón compuesta de CH3COOH (0.05M) y Ca(OH)2 (0.025M),conteniendo 12.8 % (w/w) NaCl y un pH de 4.3. Se realizó el aislamiento, identificación y el recuento de los micoorganismos predominantes, tanto del fruto como de las salmueras, durante la fermentación. Asimismo, se estudió el color, textura y las características organolépticas de los productos finales. El tercer tipo de proceso fermentativo, tipo c, dio lugar a un producto con baja sal, ausencia de microorganismos alterantes o de cualquier otra alteración, dando una textura y un color significativamente mejor y resultando con una mayor aceptación entre los consumidores (

Mitochondrial targeting adaptation of the hominoid-specific glutamate dehydrogenase driven by positive Darwinian selection

Many new gene copies emerged by gene duplication in hominoids, but little is known with respect to their functional evolution. Glutamate dehydrogenase (GLUD) is an enzyme central to the glutamate and energy metabolism of the cell. In addition to the single, GLUD-encoding gene present in all mammals (GLUD1), humans and apes acquired a second GLUD gene (GLUD2) through retroduplication of GLUD1, which codes for an enzyme with unique, potentially brain-adapted properties. Here we show that whereas the GLUD1 parental protein localizes to mitochondria and the cytoplasm, GLUD2 is specifically targeted to mitochondria. Using evolutionary analysis and resurrected ancestral protein variants, we demonstrate that the enhanced mitochondrial targeting specificity of GLUD2 is due to a single positively selected glutamic acid-to-lysine substitution, which was fixed in the N-terminal mitochondrial targeting sequence (MTS) of GLUD2 soon after the duplication event in the hominoid ancestor ~18–25 million years ago. This MTS substitution arose in parallel with two crucial adaptive amino acid changes in the enzyme and likely contributed to the functional adaptation of GLUD2 to the glutamate metabolism of the hominoid brain and other tissues. We suggest that rapid, selectively driven subcellular adaptation, as exemplified by GLUD2, represents a common route underlying the emergence of new gene functions

Nervous - system specific glutamate dehydrogenase: effect of regulatory mutations on basal activity and structure of the enzyme

Glutamate dehydrogenase (GDH), an enzyme central to glutamate metabolism and subject to complex allosteric regulation, exists in humans in two isoforms: the housekeeping hGDH1, encoded by the GLUD1 gene, and hGDH2, which is expressed mainly in brain and testis and encoded by GLUD2, a gene that emerged through retroposition ~20 million years ago. Despite 97% sequence homology, with only 15 aminoacid differences between hGDH1 and hGDH2, the two isoenzymes differ markedly in their properties: hGDH2 displays a substantially lower basal activity in absence of activators, increased resistance to GTP inhibition, and decreased thermostability. In this work we explore structure-function relationships of the two isoenzymes through mutagenesis and functional studies on wild-type and mutant hGDHs. We show that basal activity of hGDH2 in vitro is dependent on enzyme concentration, temperature and buffer composition. Furthermore, we show that the aminoacid differences R443S and G456A in the allosteric region of the enzyme, shown previously to diminish basal activity and to increase GTP-resistance, respectively, cannot reproduce the unique properties of hGDH2: the hGDH1- R443S/G456A double mutant has much lower basal activity and heat resistance than hGDH2, and is not activated by leucine. A chimeric enzyme, featuring all 4 aminoacid differences in the allosteric region (hGDH1-M415L/R443S/G456A/R470H), can also not reproduce the properties of hGDH2. The S174N aminoacid change, however, introduced into the R443S/G456A double mutant, makes the resulting enzyme sensitive to leucine activation and increases its basal activity and heat stability. Thus, aminoacid changes outside the allosteric region are crucial for the unique properties of hGDH2. In addition, we show that basal activity, heat stability and resistance to inhibition by estrogens are directly related, interlinked to each other properties of hGDHs. Finally, we show that a polymorphism in hGDH2 (S445A), that has been associated to accelerated onset of Parkinson’s disease, probably exerts its effect by increasing hGDH2’s basal activity and does not affect GTP inhibition. Mutations in the same region of hGDH1 (Q441R, S445L, S448P, K450E, H454Y), which cause the hyperinsulinism-hyperammonemia syndrome through increasing hGDH1’s resistance to GTP, do not have a similar effect in GTP-regulation when introduced to hGDH2, but can instead cause alterations in basal activity, depending on their exact location.Η γλουταμική αφυδρογονάση (GDH), ένζυμο σημαντικό για το μεταβολισμό του γλουταμικού και με σύνθετη αλλοστερική ρύθμιση, υπάρχει στον άνθρωπο σε δύο ισομορφές: την πανταχού εκφραζόμενη hGDH1 εκ του γονιδίου GLUD1 και την hGDH2, εκφραζόμενη κυρίως στον εγκέφαλο και τους όρχεις, κωδικοποιούμενη από το γονίδιο GLUD2, που προέκυψε από ρετρομετάθεση πριν ~20 εκ. έτη. Παρά την κατά 97% ομολογία και τις μόλις 15 αμινοξικές διαφορές, τα δύο ισοένζυμα διαφέρουν στις ιδιότητές τους: η hGDH2 έχει αρκετά χαμηλότερη βασική δραστηριότητα απουσία ενεργοποιητών, μεγαλύτερη αντοχή στην αναστολή από GTP και μειωμένη θερμοαντοχή. Στην παρούσα μελέτη διερευνούμε σχέσεις δομής-λειτουργίας των δύο ισοενζύμων μέσω μεταλλαξιογένεσης και λειτουργικής μελέτης μεταλλαγμένων και μη hGDHs. Δείχνουμε ότι η βασική δραστηριότητα της hGDH2 in vitro εξαρτάται από τη συγκέντρωση του ενζύμου, τη θερμοκρασία και τη σύσταση του διαλύματος. Επίσης, αποδεικνύουμε ότι οι αμινοξικές αλλαγές R443S και G456A στην αλλοστερική περιοχή του ενζύμου, που έχουν συσχετισθεί σε προηγούμενη μελέτη με μηδενισμό της βασική δραστηριότητας και αυξημένη αντοχή στην αναστολή από GTP αντίστοιχα, δεν αρκούν για να εξηγήσουν τις ιδιότητες της hGDH2: Το διπλό μετάλλαγμα hGDH1-R443S/G456A έχει βασική δραστηριότητα και θερμοαντοχή πολύ χαμηλότερες της hGDH2, ενώ δεν ενεργοποιείται από λευκίνη. Ένα χιμαιρικό ένζυμο που φέρει και τις 4 αλλαγές στην αλλοστερική περιοχή (hGDH1-M415L/R443S/G456A/R470H), επίσης δεν αναπαράγει τις ιδιότητες της hGDH2. H αμινοξική αλλαγή S174N, όμως, προστιθέμενη στο διπλό μετάλλαγμα R443S/G456A, κάνει το ένζυμο δεκτικό στην ενεργοποίηση από λευκίνη, ενώ αυξάνει τη βασική δραστηριότητα και τη θερμοαντοχή του. Άρα, αμινοξικές διαφορές εκτός της αλλοστερικής περιοχής είναι κομβικές για τις ιδιότητες της hGDH2. Επίσης, δείχνουμε ότι η βασική δραστηριότης, η θερμοαντοχή και η αντίσταση στην αναστολή από οιστρογόνα συνδέονται με αναλογική σχέση μεταξύ τους. Τέλος, ο πολυμορφισμός S445A της hGDH2, που συνδέεται με ταχύτερη έναρξη Νόσου του Πάρκινσον, πιθανότατα δρά μέσω αύξησης της βασικής δραστηριότητας του ενζύμου, ενώ η αναστολή από GTP δεν επηρεάζεται. Μεταλλάξεις στην περιοχή αυτή (Q441R, S445L, S448P, K450E, H454Y) που προκαλούν σύνδρομο υπερινσουλινισμού-υπεραμμωνιαιμίας όταν επισυμβούν στη hGDH1, αυξάνοντας την αντοχή της στο GTP, δεν έχουν παρόμοιο αποτέλεσμα στη ρύθμιση της hGDH2. Μπορούν, όμως, να μεταβάλλουν τη βασική της δραστηριότητα, ανάλογα με την ακριβή τους εντόπιση

Identidad y Pedagogía Intercultural

Las actividades humanas, de ayer y de hoy, han provocado y siguen demandando, más que nunca, importantes reestructuraciones sociales, económicas y políticas, cuyo resultado, a menudo, ha estado relacionado tímidamente con eso que hoy denominamos con tanto entusiasmo "multiculturalidad", en un intento de presentarlo, analizarlo e interpretarlo como si fuera la excepción y no la regla. Y si en nuestros días se habla más de la diversidad, la multiculturalidad y las posibles maneras de afrontar dichas situaciones, las razones han de buscarse más en los cambios que se han producido a nivel geopolítico y económico, que en dramáticos cambios demográficos dentro del mundo desarrollado. La cuestión de la diversidad cultural se ha convertido en un tema fundamental en multitud de Estados y sociedades del mundo. No obstante, el propio término de educación intercultural, aunque en los últimos años tiende a predominar en Europa, no es utilizado del mismo modo en el mundo anglosajón, donde se prefiere el término educación multicultural (multicultural education)

Identity and intercultural pedagogy

Las actividades humanas, de ayer y de hoy, han provocado y siguen demandando, más que nunca, importantes reestructuraciones sociales, económicas y políticas, cuyo resultado, a menudo, ha estado relacionado tímidamente con eso que hoy denominamos con tanto entusiasmo "multiculturalidad", en un intento de presentarlo, analizarlo e interpretarlo como si fuera la excepción y no la regla. Y si en nuestros días se habla más de la diversidad, la multiculturalidad y las posibles maneras de afrontar dichas situaciones, las razones han de buscarse más en los cambios que se han producido a nivel geopolítico y económico, que en dramáticos cambios demográficos dentro del mundo desarrollado. La cuestión de la diversidad cultural se ha convertido en un tema fundamental en multitud de Estados y sociedades del mundo. No obstante, el propio término de educación intercultural, aunque en los últimos años tiende a predominar en Europa, no es utilizado del mismo modo en el mundo anglosajón, donde se prefiere el término educación multicultural (multicultural education).Past and present human activities have caused and continue claiming for, more than ever, important social, economical and political reconstructions. The results of these reconstructions have often been slightly related with what we nowadays enthusiastically call "multiculturalism", in an attempt to display, analyze and interpret it as if it was the exception, not the rule. The reasons why nowadays more is said about multiculturalism and the possible ways to face these sitautions have to be sought in the dramatic geopolitical changes that have taken place in the developed world. The issue of cultural diversity has become fundamental in many states and societies all over the world. However, the term intercultural education, although it has tended to prevail in Europe for the last years, it is not used in the same way in the Anglo-Saxon world. Instead of this term, the Anglo - Saxons prefer the term multicultural education

Similarity Among Physical Phenomena Recognized on the Basis of the Classification of Existing Knowledge

This work presents the synthetical mathematical analysis of available knowledge regarding physical phenomena of research interest. The work is not focusing on providing the phenomena according to the physical laws but rather because of them, hence, it is grounded on the philosophically defined concept of "similarity", and progresses to the mathematical treatments of those factors and parameters that are involved into the similarity validation among physical phenomena.A critical validation regarding the effectiveness of such an approach was also performed, in order to conceptualize the relevance of the factors and parameters interactions as a potential control tool against engineering-based hypothesis. Such factors and parameters are generated through the description and delimitation of the system of interest. A "matrix" is used for the classification of the existing knowledge regarding this system. It is consisted of the categorical descriptors of the system in question and the levels of these descriptors.A mathematical analysis of this "matrix" supports that all the existent perceptions of a physical phenomenon constitute a four-dimensional vector space. Within this space, the concept of similarity allows for the definition on which of a specific non-linear mapping that might be applied to strictly classify the existing knowledge about the phenomenon in question.Similarity is used here to define the conditions and the constrains that this mapping must satisfy. In conclusion, the applicability of the suggested approach on an engineering approach regarding a physical problem, was also demonstrated in this study

Identidad y pedagogía intercultural

Las actividades humanas, de ayer y de hoy, han provocado y siguen demandando, más que nunca, importantes reestructuraciones sociales, económicas y políticas, cuyo resultado, a menudo, ha estado relacionado tímidamente con eso que hoy denominamos con tanto entusiasmo "multiculturalidad", en un intento de presentarlo, analizarlo e interpretarlo como si fuera la excepción y no la regla. Y si en nuestros días se habla más de la diversidad, la multiculturalidad y las posibles maneras de afrontar dichas situaciones, las razones han de buscarse más en los cambios que se han producido a nivel geopolítico y económico, que en dramáticos cambios demográficos dentro del mundo desarrollado. La cuestión de la diversidad cultural se ha convertido en un tema fundamental en multitud de Estados y sociedades del mundo. No obstante, el propio término de educación intercultural, aunque en los últimos años tiende a predominar en Europa, no es utilizado del mismo modo en el mundo anglosajón, donde se prefiere el término educación multicultural (multicultural education)