Τα μαθηματικά στο χώρο εργασίας της ωρολογοποιίας

Η παρούσα εργασία αφορά τις μαθηματικές έννοιες και πρακτικές που εμφανίζονται σε χώρους εργασίας και αποτελεί μια διερεύνηση της μαθηματικής σκέψης που συγκροτείται στον επαγγελματικό χώρο της ωρολογοποιίας. Πρόκειται για μία μελέτη περίπτωσης, στο πλαίσιο της εθνογραφικής παρατήρησης, τεχνικών ωρολογοποιίας, είτε επισκευαστών είτε κατασκευαστών, με χρόνια εμπειρία στον εν λόγω χώρο. Εξετάζεται η φύση των μαθηματικών πρακτικών και εννοιών οι οποίες υπάρχουν στον χώρο, οι συνθήκες και οι τρόποι που εμφανίζονται, η εξάρτησή τους από το εργασιακό πλαίσιο καθώς και η διαφάνειά τους όσον αφορά στον ρόλο των χρησιμοποιούμενων εργαλείων. Ακόμα, μελετάται η αναγνώρισή τους από τους συμμετέχοντες, ο τρόπος που επικοινωνούν τις μαθηματικές έννοιες με τον ερευνητή και τις ερμηνεύουν σε αυτόν, καθώς και ο τρόπος που τις χρησιμοποιούν. Τα ερευνητικά δεδομένα, προκύπτουν από εθνογραφικής φύσης παρατηρήσεις, όπως η παρατήρηση της επαγγελματικής δραστηριότητας των τεχνιτών, η καταγραφή σημειώσεων πεδίου, η μελέτη των εγχειριδίων που χρησιμοποιούν αλλά και οι συνεντεύξεις και συζητήσεις με τους συμμετέχοντες. Η ανάλυση των δεδομένων, πραγματοποιείται με τη χρήση της Θεωρίας της Δραστηριότητας ως θεωρητικό εργαλείο. Στο συστημικό δίκτυο που αναδύεται, εμφανίζονται μαθηματικές έννοιες και διαδικασίες καθώς και η άμεση ή έμμεση χρήση αυτών λόγω της διαμεσολάβησης μαθηματικών και μη εργαλείων με διαφανή ή μη ρόλο. Παράλληλα, η αναγνώρισή της χρήσης αυτών εκ μέρους των συμμετεχόντων, παρουσιάζει ποικιλία. Σημαντικά στοιχεία στην ερμηνεία των αποτελεσμάτων θεωρούνται το γνωστικό υπόβαθρο αλλά και το πλαίσιο της εργασίας του καθενός από τους συμμετέχοντες, καθώς και οι συγκεκριμένοι εργασιακοί τους στόχοι. Η δημιουργία του συστημικού δικτύου προέρχεται από την ανάλυση τριών εργασιακών δράσεων των συμμετεχόντων. Η πρώτη δράση είναι ο έλεγχος και η ρύθμιση των παλμών ανά ώρα του ρολογιού και σχετίζεται με τη μαθηματική έννοια της περιοδικότητας. Η δεύτερη είναι η τοποθέτηση του εκκρεμούς στο χώρο λειτουργίας του, όπου χρησιμοποιείται η μαθηματική έννοια της συμμετρίας, ενώ η τρίτη είναι η εύρεση των δοντιών των γραναζιών σχετίζεται με τη μαθηματική έννοια της αναλογίας. Τέλος, παρουσιάζεται η σχέση των μαθηματικών αυτών πρακτικών με τα σχολικά μαθηματικά και οι τρόποι που τέτοιου είδους δραστηριότητες μπορούν να αποτελέσουν πηγή για το σχεδιασμό σχετικών μαθηματικών έργων σε επίπεδο γενικής ή επαγγελματικής εκπαίδευσης. Εν τέλει, συζητείται η εκπαιδευτική αξία της έρευνας και των αποτελεσμάτων της.This paper pertains to mathematical concepts and practices in workplaces and constitutes an investigation of the mathematical thinking that is formed in the professional field of watchmaking. This is a case study, in the context of ethnographic observation, of watchmaking technicians, repairers or manufacturers, with plenty of working experience. The nature of the mathematical practices and concepts that exist in the workplace, the situations and the ways under they are presented, their dependence on the work context as well as their transparency regarding the role of the tools used, are examined. However, the participants' recognition of the mathematical concepts, the way they communicate them with the researcher and interpret them, as well as the way they use them, are studied. Data were collected through ethnographic observations, such as the observation of the professional activity of the craftsmen, the recording of field notes, the study of the manuals they use but also the interviews and discussions with the participants. The data analysis is performed using the Activity Theory as a theoretical tool. In the emerging systemic network, mathematical concepts and procedures appear as well as their direct or indirect use due to the mediation of mathematical and non-transparent tools with a transparent or non-transparent role. At the same time, the recognition of their use by the participants is varied. Important elements in the interpretation of the results are considered the cognitive background but also the context of the work of each of the participants, as well as their specific work goals. The formation of the systemic network arises from the analysis of three work actions of the participants. The first action is to control and regulate the beats per hour of the clock and is related to the mathematical concept of periodicity. The second is the placement of the pendulum in its place of operation, where the mathematical concept of symmetry is used, while the third is the finding of the teeth of the gears, which is related to the mathematical concept of proportion. Finally, the relationship of these mathematical practices with school mathematics is presented and the ways in which such activities can be a source for the design of relevant mathematical projects at the level of general or vocational education. Finally, the educational value of the research and its results is discussed

Effect of Pt nanoparticle decoration on the H2 storage performance of plasma-derived nanoporous graphene

A nanoporous and large surface area (∼800 m2/g) graphene-based material was produced by plasma treatment of natural flake graphite and was subsequently surface decorated with platinum (Pt) nano-sized particles via thermal reduction of a Pt precursor (chloroplatinic acid). The carbon-metal nanocomposite showed a ∼2 wt% loading of well-dispersed Pt nanoparticles (<2 nm) across its porous graphene surface, while neither a significant surface chemistry alteration nor a pore structure degradation was observed due to the Pt decoration procedure. The presence of Pt seems to slightly promote the hydrogen sorption behavior at room temperature with respect to the pure graphene, thus implying the rise of “weak” chemisorption phenomena, including a potential hydrogen “spillover” effect. The findings of this experimental study provide insights for the development of novel graphene-based nanocomposites for hydrogen storage applications at ambient conditions

How breast cancer treatments affect the quality of life of women with non-metastatic breast cancer one year after surgical treatment: a cross-sectional study in Greece

Background: The continuously increasing survivorship of female breast cancer makes the monitoring and improvement of patients' quality of life ever so important. While globally there is a growing body of research on health-related quality of life 1 year after surgical treatment for non-metastatic breast cancer, up-to-date information regarding Greek patients is scarce. Objective: To measure the level of QoL of non-metastatic BC survivors in Greece 1 year after surgery. Methods: A sample of 200 female breast cancer survivors aged 18 to 75, who followed up as outpatients in five public hospitals were included in this cross-sectional study. All recruited patients agreed to participate in the study (100% response rate). Quality of life data were collected through the EORTC QLQ-C30 as well as BR23 questionnaires. Results: Cronbach's alpha for all scales of the two questionnaires was from 0.551 to 0.936 indicating very good reliability. According to the Multiple Linear Regression, older patients showed a lower future perspective (p =.031), with those living in rural areas, which was associated with more financial difficulties (p =.001). Women with tertiary education and those who had been hospitalized in a university hospital recorded better on global health status (p =.003 and.000 respectively). Patients who underwent chemotherapy reported better scores in the emotional function sub-scale (p =.025). Women with reconstruction and at least one complication appeared to have significantly better scores in future perspective and social function (p =.005,.002 respectively). Conclusions: Breast cancer survivors were found to have an overall good quality of life, functioning/symptoms scores and were satisfied with the provided care

Predictions for the future of kallikrein-related peptidases in molecular diagnostics

Kallikrein-related peptidases (KLKs) form a cancer-related ensemble of serine proteases. This multigene family hosts the most widely used cancer biomarker that is PSA-KLK3, with millions of tests performed annually worldwide. The present report provides an overview of the biomarker potential of the extended KLK family (KLK1-KLK15) in various disease settings and envisages approaches that could lead to additional KLK-driven applications in future molecular diagnostics. Particular focus is given on the inclusion of KLKs into multifaceted cancer biomarker panels that provide enhanced diagnostic, prognostic and/or predictive accuracy in several human malignancies. Such panels have been described so far for prostate, ovarian, lung and colorectal cancers. The role of KLKs as biomarkers in non-malignant disease settings, such as Alzheimer’s disease and multiple sclerosis, is also commented upon. Predictions are given on the challenges and future directions regarding clinically oriented KLK research

Breast Cancer Detection in Mammogram Medical Images with Data Mining Techniques

Part 8: Third Workshop on Artificial Intelligence Applications in Biomedicine (AIAB 2013)International audienceA domain of interest for data mining applications is the study of biomedical data which, in combination with the field of image processing, provide thorough analysis in order to discover hidden patterns or behavior. Towards this direction, the present paper deals with the detection of breast cancer within digital mammography images. Identification of breast cancer poses several challenges to traditional data mining applications, particularly due to the high dimensionality and class imbalance of training data. In the current approach, genetic algorithms are utilized in an attempt to reduce the feature set to the informative ones and class imbalance issues were also dealt by incorporating a hybrid boosting and genetic sub-sampling approach. As regards to the feature extraction approach, the idea of trainable segmentation is borrowed, using Decision Trees as the base learner. Results show that the best precision and recall rates are achieved by using a combination of Adaboost and k-Nearest Neighbor

Evaluation of the dynamic elastic constants of fibrous composites considering the 3-Phases model with mesophase layer

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Εφαρμοσμένη Μηχανική