24 research outputs found
A program for performing exact quantum dynamics calculations using cylindrical polar coordinates : a nanotube application
No full textA program that uses the time-dependent wavepacket method to study the motion of structureless particles in a force field of quasi-cylindrical symmetry is presented here. The program utilises cylindrical polar coordinates to express the wavepacket, which is subsequently propagated using a Chebyshev expansion of the Schrödinger propagator. Time-dependent exit flux as well as energy-dependent S matrix elements can be obtained for all states of the particle (describing its angular momentum component along the nanotube axis and the excitation of the radial degree of freedom in the cylinder). The program has been used to study the motion of an H atom across a carbon nanotube
Η Επίδραση της Εκπαιδευτικής Ρομποτικής στην Ανάπτυξη Γλωσσικών Δεξιοτήτων: Διδακτική προσέγγιση με τη χρήση του LEGO Education SPIKE Essential Set
No full textΣτη σύγχρονη εποχή, η παραδοσιακή μέθοδος διδασκαλίας δέχεται κριτική και χαρακτηρίζεται ως παρωχημένη, με την επιστημονική και εκπαιδευτική κοινότητα να αμφισβητεί την αποτελεσματικότητά της. Ταυτόχρονα, τα Νέα Προγράμματα Σπουδών (ΠΣ-21) της Νεοελληνικής Γλώσσας και των Τεχνολογιών της Πληροφορίας και των Επικοινωνιών (ΤΠΕ) στη Δημοτική Εκπαίδευση προωθούν μια καινοτόμα προσέγγιση, καθώς εισάγουν τη μαθητοκεντρική θεώρηση του περιεχομένου, ενθαρρύνοντας την ομαδοσυνεργατική μάθηση, τη μάθηση μέσω εξερεύνησης, τη μάθηση μέσω εργασιών, την ανάπτυξη της υπολογιστικής σκέψης παράλληλα με τη σχεδιαστική, τον πειραματισμό και την επίλυση πραγματικών προβλημάτων. Αυτοί οι στόχοι υπερβαίνουν το πλαίσιο της παραδοσιακής διδασκαλίας, και γι’ αυτό η προσέγγιση ST(R)E(A)M αναδεικνύεται ως απάντηση, ειδικά λόγω της διαθεματικότητας και της ολιστικότητας που τη διέπουν. Η παρούσα εργασία εξετάζει τον τρόπο αναπαράστασης ενός παραμυθιού από το Ανθολόγιο Λογοτεχνικών Κειμένων Α΄ και Βˊ Δημοτικού, χρησιμοποιώντας το LEGO® Education SPIKE™ Essential Set. Σκοπός της έρευνας, που διενεργήθηκε με είκοσι τέσσερις (24) μαθητές/-τριες της Βˊ Δημοτικού, είναι να διερευνήσει πώς αυτή η διαδικασία μπορεί να βελτιώσει τις κοινωνικές τους δεξιότητες και να τους/τις ενεργοποιήσει να αναπτύξουν σε δομημένο γραπτό λόγο την ιστορία που ακροάστηκαν. Οι συμμετέχοντες/-ουσες στην έρευνα κλήθηκαν να απαντήσουν σε δύο ερωτηματολόγια, τα οποία συλλέχθηκαν με τη μορφή pre-test και post-test. Προτιμήθηκαν ερωτήσεις κλειστού τύπου, που εστίαζαν στο ενδιαφέρον των μαθητών/-τριών για το γλωσσικό μάθημα, τη σύνταξη κειμένων με δομή και τη δημιουργία ιστοριών, τη συνεργασία σε ομάδες, την αποκομιδή γνώσεων από τη δραστηριότητα με τα δομικά υλικά LEGO, καθώς και την κατανόηση του οπτικού προγραμματισμού. Η δομή της εργασίας περιλαμβάνει πέντε κεφάλαια. Στο πρώτο κεφάλαιο γίνεται εισαγωγή στο θεωρητικό υπόβαθρο του θέματος. Στο δεύτερο κεφάλαιο περιγράφεται λεπτομερώς η διαδικασία εφαρμογής της διδακτικής παρέμβασης. Στο τρίτο κεφάλαιο αναλύεται η μεθοδολογία που χρησιμοποιήθηκε στην έρευνα και στο τέταρτο κεφάλαιο παρουσιάζονται με γραφήματα τα αποτελέσματα αυτής. Το πέμπτο και τελευταίο κεφάλαιο συνοψίζει την έρευνα και παρουσιάζει τα συμπεράσματα που προκύπτουν.In the contemporary era, traditional teaching methods are criticized and considered outdated, with the scientific and educational community questioning their effectiveness. Concurrently, the New Curriculum for the Greek Language and Information and Communication Technologies (ICT) in Primary Education promotes an innovative approach by introducing student-centered content, encouraging collaborative learning, exploration-based learning, task-based learning, the development of computational thinking alongside design, experimentation, and the resolution of real-world problems. These goals surpass the boundaries of traditional teaching methods, making the ST(R)E(A)M approach, especially due to its interdisciplinary and holistic nature, a suitable response. This research focuses on representing a fairytale from the «Anthology of Literary Texts A' and B' grades of Primary Education» using the LEGO® Education SPIKE™ Essential Set. The aim of the study, conducted with twenty-four (24) students from the B' grade of Primary Education, is to explore how this process can enhance their social skills and activate them to develop, in structured written form, the story they listened to. Participants in the research were required to respond to two questionnaires, collected in pre-test and post-test formats. Closed-ended questions were preferred, focusing on students' interest in the language lesson, text composition with structure, storytelling, collaboration in groups, knowledge acquisition from working with LEGO building materials, and understanding visual programming. The structure of the thesis comprises five chapters. The first chapter introduces the theoretical background of the topic. The second chapter provides a detailed description of the implementation process of the teaching intervention. The third chapter analyzes the methodology employed in the research, while the fourth chapter presents the research results through graphs. The fifth and final chapter summarizes the research and presents the conclusions drawn
Quantitative research of economic factors in relation with the temporal changes of the landscape of Crete
No full textIn the present study a methodology was used in order to be found the relationship between the socio-economic factors and the landscape change of Crete. At first, a landscape dynamic model was chosen, which consists of socio-economic factors, natural factors and the land use. Then, a variety of socio-economic, natural and land use data were gathered for each municipality. The most important sources of the above mentioned data gathering were “The National Statistic Service of Greece” and the database of CORINE program. The second step of this study was the indicators choice and their calculation. These indicators were estimated spatial-temporally, in order their variation tendency to be estimated. Landscape indicators were chosen in order to determine the landscape structure (land use, diversity indices, evenness indices, similarity indices). The choice of the socio-economic indicators refers to the population structure and the production sectors and it represents indicators that relate with the socio-economic structure of these municipalities. A landscape tendency, more homogeneous was found from the above mentioned indicators estimation. Also, there was an obvious opposite tendency - abandonment / intensification - in mountainous municipalities in relation with the semi-mountainous and the flat ones. This tendency increases as the time elapses. Then a research was carried out in order to be found a relationship between the landscape structure and the socio-economic indicators during 1961 and 1991. A methodology based on two different groups of indicators - landscape indicators and socio-economic / natural indicators - and their descriptive ability was also applied. A Principal Component Analysis carried out on the landscape indicators, enabled us to order the municipalities in a plane, the dimensions of which mainly depend on the most representative landscape indicators, those of greatest loading in the analysis. These dimensions represent the main variation tendencies of the landscape during 1961 and 1991 and were considered as variables dependent on regression models. The independent variables of those models are the socio-economic and natural indicators. The procedure enables us to obtain a dependence model with a limited number of socio-economic indicators. Finally, indicators identified as important to landscape change were examined by multiple regression techniques. The independent variables of the models were derived from the following four groups of indicators, the socio-economic indicators at the beginning of the period, their temporal changes during this period, the landscape indicators at the beginning of the period and the natural indicators. By using a principal component analysis, the more closely correlated indicators were not taken into account. Socio-economic indicators had the largest contribution. The results from the above mentioned methodology enable us to convey these relationships to simulated scenarios and evaluate the implications of certain socio-economic policies for landscape typology.Σε αυτή την εργασία διερευνάται η σχέση μεταξύ των κοινωνικο-οικονομικών παραγόντων και της μεταβολής του τοπίου στην Κρήτη με την ανάπτυξη διαφόρων μεθοδολογιών. Αρχικά, επιλέχθηκε ένα λειτουργικό πρότυπο δυναμικής του τοπίου, το οποίο αποτελείται από τους κοινωνικο-οικονομικούς παράγοντες, τους φυσικούς παράγοντες και τις χρήσεις γης. Στην συνέχεια δεδομένα σχετικά με τους παραπάνω παράγοντες αναζητήθηκαν και συλλέχθηκαν σε επίπεδο Δημοτικού Διαμερίσματος. Κυριότερες πηγές των παραπάνων δεδομένων ήταν η ΕΣΥΕ και η βάση δεδομένων του προγράμματος CORINE. Το δεύτερο βήμα, ήταν η επιλογή και υπολογισμός δεικτών, οι οποίοι εκτιμώμενοι χωροχρονικά, δείχνουν την τάση μεταβολής του τοπίου και την τάση μεταβολής των κοινωνικο-οικονομικών παραγόντων. Οι δείκτες του τοπίου που επιλέχθηκαν προσδιορίζουν τη μορφή του τοπίου (χρήσεις γης, δείκτης του Shannon, δείκτης ομοιογένειας, δείκτης ομοιότητας, κ.τ.λ.). Οι κοινωνικο-οικονομικοί δείκτες, που επιλέχθηκαν αναφέρονται στην δομή του πληθυσμού, στους παραγωγικούς τομείς και γενικότερα αντιπροσωπεύουν δείκτες που σχετίζονται με την κοινωνικο-οικονομική δομή. Από τον υπολογισμό των παραπάνω δεικτών προέκυψε μία τάση ομοιογενοποίησης του τοπίου διαχρονικά. Επίσης επιβεβαιώθηκε η αντίθετη τάση - εγκατάλειψη / εντατικοποίηση - που παρουσιάζεται στα ορεινά Δημοτικά Διαμερίσματα σε σχέση με τα ημιορεινά και πεδινά. Στην συνέχεια διερευνήθηκε η σχέση μεταξύ της δομής του τοπίου και των κοινωνικο-οικονομικών δεικτών για το 1961 και το 1991 με την ανάπτυξη μιας μεθοδολογίας στηριζόμενης σε στατιστικές μεθόδους. Χρησιμοποιήθηκαν δύο ομάδες δεικτών, η ομάδα των κοινωνικο-οικονομικών και φυσικών δεικτών και η ομάδα των δεικτών τοπίου. Η εφαρμογή της ανάλυσης των κυρίων συνιστωσών για τους δείκτες τοπίου των 38 Δημοτικών Διαμερισμάτων, τοποθέτησε θεωρητικά αυτά στον χώρο, οι διαστάσεις του οποίου εξαρτώνται κυρίως από τους πιο αντι-προσωπευτικούς δείκτες τοπίου με τις υψηλότερες φορτίσεις. Αυτές οι διαστάσεις αντιπροσωπεύουν τις κυριότερες τάσεις μεταβολής για το 1961 και το 1991 και θεωρήθηκαν ως εξαρτημένες μεταβλητές στα μοντέλα παλινδρόμησης, όπου οι ανεξάρτητες μεταβλητές ήταν οι κοινωνικο-οικονομικοί δείκτες. Καθένα από τα μοντέλα πολλαπλής παλινδρόμησης που προέκυψε επέτρεψε τον προσδιορισμό ενός αριθμού κοινωνικο-οικονομικών δεικτών, που να χαρακτηρίζουν την μεταβολή του τοπίου. Τελικά, δείκτες, που αναγνωρίστηκαν ως σημαντικοί για την μεταβολή του τοπίου (19961-1991), εξετάστηκαν με μοντέλα πολλαπλής παλινδρόμησης. Οι ανεξάρτητες μεταβλητές προήρθαν από τις εξής τέσσερις ομάδες δεικτών: Αρχικοί κοινωνικο-οικονομικοί δείκτες (1961), μεταβολή κοινωνικο-οικονομικών δεικτών (1961-1991), αρχικοί δείκτες τοπίου (1961) και φυσικοί δείκτες. Η επιλογή τους έγινε με τη βοήθεια της ανάλυσης των κυρίων συνιστωσών. Δείκτες από όλες τις ομάδες δεικτών είχαν την συνεισφορά τους, στην μεταβολή του τοπίου, με σημαντικότερους τους κοινωνικο-οικονομικούς. Τα αποτελέσματα από την ανάπτυξη των παραπάνω μεθοδολογιών μπορούν να χρησιμοποιηθούν στην εφαρμογή προσομοιωμένων σεναρίων και να εκτιμηθούν οι επιπτώσεις κοινωνικο-οικονομικών πολιτικών στην τυπολογία του τοπίου
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Characterisation of the avian TopBP1 protein and its functions
No full textOne of the proteins that lie at the heart of the DNA Damage Response (DDR) is Topoisomerase II-binding protein I (TopBP1). TopBP1 was initially identified and has been extensively studied in the yeast model organisms. However, the lack of readily available tools, including genetically defined mutant cell lines, has rendered the characterisation of TopBP1 in higher eukaryotes more challenging. Sequence information obtained from the characterisation of the gallus gallus TopBP1 mRNA revealed a different splicing pattern at the 5’end to the one reported in the Genome Browser. Our assembled TopBP1 mRNA sequence containing a novel open reading frame (ORF) enabled the creation of a conditional knockout cell line of TopBP1 in DT40, which has been impossible with the use of the annotated cDNA sequence. Thus the avian TopBP1 ORF identified herein contained the necessary function(s) to sustain viability of DT40 cells in the absence of the endogenous protein. Additionally, the establishment of an isogenic set of stable cell lines from the chicken B cell line DT40 by targeted deletion of the TopBP1 alleles revealed a gene dosage-dependent reduction of the TopBP1 protein levels and functions. This work establishes a novel gene-dosage system that can be used for the knock in of point mutations within the endogenous TopBP1 locus. Using this system, a novel characterisation of knock-in point mutants of the ATR Activation Domain (AAD) of TopBP1 was carried out, providing in vivo evidence of its DDR function(s). Finally, a stably integrated overexpression system (SIOS) capable of producing increased amounts of a protein of interest has been established in DT40 cells. SIOS represents an easy to use versatile system for various experimental purposes in the field of DT40. The work presented in this thesis represents a novel characterisation of the avian TopBP1 mRNA and the TopBP1 protein and its functions. This is crucial to gain insight into the mechanistics of the DDR network and the genetic instability characterising cancer development
Characterisation of the avian TopBP1 protein and its functions
No full textOne of the proteins that lie at the heart of the DNA Damage Response (DDR) is Topoisomerase II-binding protein I (TopBP1). TopBP1 was initially identified and has been extensively studied in the yeast model organisms. However, the lack of readily available tools, including genetically defined mutant cell lines, has rendered the characterisation of TopBP1 in higher eukaryotes more challenging. Sequence information obtained from the characterisation of the gallus gallus TopBP1 mRNA revealed a different splicing pattern at the 5’end to the one reported in the Genome Browser. Our assembled TopBP1 mRNA sequence containing a novel open reading frame (ORF) enabled the creation of a conditional knockout cell line of TopBP1 in DT40, which has been impossible with the use of the annotated cDNA sequence. Thus the avian TopBP1 ORF identified herein contained the necessary function(s) to sustain viability of DT40 cells in the absence of the endogenous protein. Additionally, the establishment of an isogenic set of stable cell lines from the chicken B cell line DT40 by targeted deletion of the TopBP1 alleles revealed a gene dosage-dependent reduction of the TopBP1 protein levels and functions. This work establishes a novel gene-dosage system that can be used for the knock in of point mutations within the endogenous TopBP1 locus. Using this system, a novel characterisation of knock-in point mutants of the ATR Activation Domain (AAD) of TopBP1 was carried out, providing in vivo evidence of its DDR function(s). Finally, a stably integrated overexpression system (SIOS) capable of producing increased amounts of a protein of interest has been established in DT40 cells. SIOS represents an easy to use versatile system for various experimental purposes in the field of DT40. The work presented in this thesis represents a novel characterisation of the avian TopBP1 mRNA and the TopBP1 protein and its functions. This is crucial to gain insight into the mechanistics of the DDR network and the genetic instability characterising cancer development
Characterisation of a stably integrated expression system for exogenous protein expression in DT40 [version 1; referees: 2 approved, 1 approved with reservations]
No full textThe use of constitutive promoters to drive exogenous protein expression is an important tool for the study of diverse biological processes. To create and characterise a stably integrated expression system for DT40 cells, we constructed integration cassettes for three commonly used promoter elements; CMV, CBA or CAG, and used these to stably integrate a TOPBP1 transgene at the OVA locus, a transcriptionally silent locus commonly used in DT40. We next performed a comparative analysis of protein expression levels and identified CAG as the most efficient of the promoter elements we have tested in DT40 cells. To assess whether the site of integration affected the levels of transgene expression, a second chromosomal locus, immediately adjacent to the endogenous TOPBP1 gene, was tested for CAG. No major differences in TopBP1 overexpression were observed. This confirms that use of the OVA locus for integrating transgenes is a rational choice for DT40. Finally, we demonstrate that our stably integrated overexpression system (SIOS) constructs can be efficiently excised by the induction of tamoxifen-regulated Cre expression. Taken together, SIOS is an easy-to-use and versatile system for constitutive, reversible exogenous protein production that provides a range of potential expression levels. This will be a useful experimental tool for future DT40 experiments
Non-Born-Oppenheimer MCTDH calculations on the confined H2+ molecular ion
No full textA multiconfiguration time-dependent Hartree method based on non-orthogonal coordinates has been developed. The method has been applied to the calculations of the properties of atomic and molecular systems beyond the Born–Oppenheimer approximation, treating electrons and nuclei on a similar footing. Example calculations have been performed on the confined ion, treated as a genuine three-particle system. With only two orbitals per degree of freedom to begin with, the confinement energy levels as well as the origin of the genuinely bound energy levels have been generated. The initial time evolution of the time-dependent orbitals is also shown
Local application of volatile anesthetics attenuates the response to a mechanical stimulus in humans
No full textPurpose: Volatile anesthetics may cause local hyperalgesia and/or analgesia. This double-blind randomized study investigated the effect of these medications when applied locally on the response to a mechanical stimulus. Methods: In experiment I, standard commercial preparations of halothane ( mL, isoflurane 1.5 mL and sevoflurane 2.7 mL were randomly applied on the forearm of 30 volunteers for 30 min, after which the response to a mechanical stimulus was recorded. The other forearm received water as control. The next day, the experiment for each anesthetic was repeated in a reverse fashion. Thirty minutes after the application, the response to a standardized mechanical stimulus was recorded. In experiments 2 and 3, the response to the same mechanical stimulus was tested after local applications of 2, 4, and 6 mL of halothane or after a local application of 5 mL sevoflurane respectively. Results: Low doses of the three anesthetics did not alter the response to the mechanical stimulus (F = 3.055, df = 1,174, P = 0.082). Two, 4, and 6 mL of halothane attenuated the response to the mechanical stimulus by 36%, 27% and 29% respectively (F = 9.586, df = 1, 114, P = 0.002). Five millilitres of sevoflurane attenuated the response to the mechanical stimulus by 36% (F = 5.111, df = 19, P < 0.001). Conclusion: Low liquid volumes of volatile anesthetics, when applied locally to the skin, did not influence the response to a mechanical stimulus, but higher volumes attenuated this response
Predicting time-windows for full recovery of postfire regenerating Pinus halepensis Mill. forests after a future wildfire
No full textA regeneration predictor (RP) has been elaborated to forecast the minimal inter-fire period, required for full recovery (assumed at 1,000 mature stems ha-1, a typical value for a dense pine forest) of an even-aged, postfire regenerating Pinus halepensis population after a subsequent wildfire, in the future. The study has been conducted in three Aleppo pine forests of northern Euboea Island, Greece. Postfire field surveys of sapling growth, sapling density and reproductive dynamics (cone-bearing population fraction, annual cone and seed production per sapling, canopy seed bank build-up) were carried out for three, consecutive growing seasons (years). Additional postfire parameters, with values estimated from literature data, have been also included in order to devise the RP. In the cases of the three populations studied, the application of this RP provides time-windows for full recovery after a recurrent fire, as short as 10-15, 8-11 and 7-11 years, respectively (values corresponding to best and worst scenarios). It is suggested that in even-aged, postfire regenerating Aleppo pine populations, the minimal inter-fire period required for full recovery can be predicted by monitoring a few selected variables, namely (a) sapling density, (b) vegetative to reproductive shift dynamics, and (c) cones/sapling and germinable seeds/cone, for at least 2 years (either consecutive or 2-3 years apart) at a postfire age of 7-12 years. © 2013 Springer Science+Business Media Dordrecht
