786 research outputs found
Exploiting Amorphous Data Parallelism to Speed-Up Massive Time-Dependent Shortest-Path Computations
Get PDFWe aim at exploiting parallelism in shared-memory multiprocessing systems, in order to speed up the execution time with as small redundancy in work as possible, for an elementary task that comes up frequently as a subroutine in the daily maintenance of large-scale time-dependent graphs representing real-world relationships or technological networks: the many-to-all time-dependent shortest paths (MATDSP) problem. MATDSP requires the computation of one time-dependent shortest-path tree (TDSPT) per origin-vertex and departure-time, from an arbitrary collection of pairs of origins and departure-times, towards all reachable destinations in the graph.
Our goal is to explore the potential and highlight the limitations of amorphous data parallelism, when dealing with MATDSP in multicore computing environments with a given amount of processing elements and a shared memory to exploit. Apart from speeding-up execution time, consumption of resources (and energy) is also critical. Therefore, we aim at limiting the work overhead for solving a MATDSP instance, as measured by the overall number of arc relaxations in shortest-path computations, while trying to minimize the overall execution time. Towards this direction, we provide several algorithmic engineering interventions for solving MATDSP concerning: (i) the compact representation of the instance; (ii) the choice and the improvement of the time-dependent single-source shortest path algorithm that is used as a subroutine; (iii) the way according to which the overall work is allocated to the processing elements; (iv) the adoption of the amorphous data parallelism rationale, in order to avoid costly synchronization among the processing elements while doing their own part of the work.
Our experimental evaluations, both on real-world and on synthetic benchmark instances of time-dependent road networks, provide insight how one should organize heavy MATDSP computations, depending on the application scenario. This insight is in some cases rather unexpected. For instance, it is not always the case that pure data parallelism (among otherwise totally independent processors) is the best choice for minimizing execution times. In certain cases it may be worthwhile to limit the level of data parallelism in favor of algorithmic parallelism, in order to achieve more efficient MATDSP computations
La fouille du terrain Yannopoulos et les établissements de bains à Thasos (IIIe-VIe s.)
No full textΗ ανασκαφή του οικόπεδου Γιαννόπουλου και τα λουτρικά συγκροτήματα στη Θάσο (3ος-6ος αι. μ. Χ.)
Το άρθρο πραγματεύεται το λουτρικό συγκρότημα που ερευνήθηκε στο οικόπεδο Γιαννόπουλου στη Θάσο, τα κατασκευαστικά χαρακτηριστικά, τα ευρήματα και την ένταξή του στο αστικό περιβάλλον. Πρόκειται για ένα κτήριο ορθογώνιας κάτοψης, με 12 χώρους και τρεις οικοδομικές φάσεις. Αναγνωρί-στηκαν δύο praefurnia, δύο υπόκαυστοι και οκτώ μη-θερμαινόμενοι χώροι. Με αφορμή το λουτρό στο οικόπεδο Γιαννόπουλου, επιχειρείται μια παρουσίαση όλων των λουτρικών εγκαταστάσεων, δημόσιας και ιδιωτικής χρήσης, που έχουν εντοπιστεί στη Θάσο, εντός και εκτός του άστεως. Με βάση την έρευνά μας, διαπιστώθηκε ότι τα κτήρια στα γειτνιάζοντα οικόπεδα Γιαννόπουλου και Βέλλιου ανήκουν σε ένα ενιαίο λουτρικό οικοδόμημα. Η χρονολόγηση των εγκαταστάσεων επιβεβαιώνει τη χρήση λουτρών στη Θάσο καθ’ όλη τη διάρκεια της ρωμαϊκής και της πρωτοβυζαντινής εποχής.The excavation of the Yannopoulos plot and the bathing establishments at Thasos (3rd-6th c.)
This article concerns the bathing establishment excavated on the Yannopoulos property in the city of Thasos, its architectural particularities, the finds recovered, and its insertion in the urban environment. The twelve-room building, of rectangular plan, has three architectural phases. Two praefurnia, two hypocausts, and eight non-heated rooms have been distinguished. The study of this baths offers an occasion to present the totality of bathing establishments, public and private, identified on the island, in the city as well as outside. During our research it has become clear that the buildings on the neighbouring Yannopoulos and Vellios plots belong to a single complex. The dating of the installations confirms the use of baths at Thasos throughout the roman and protobyzantine periods.Cet article traite de l’établissement de bains fouillé dans le terrain Yannopoulos à Thasos, de ses particularités architecturales, des trouvailles qui y ont été faites et de son insertion dans l’environnement urbain. Ce bâtiment de douze pièces, de plan rectangulaire, comporte trois phases architecturales. On y a reconnu deux praefurnia, deux hypocaustes et huit pièces non chauffées. L’étude de ce bain est l’occasion d’essayer de présenter l’ensemble des établissements balnéaires, publics et privés, qui ont été localisés à Thasos, aussi bien dans la ville qu’en dehors. Lors de notre recherche, il est apparu que les bâtiments des terrains Yannopoulos et Vellios, voisins, appartiennent à un seul et même complexe. La datation des installations confirme l’usage des bains à Thasos pendant toute la durée des époques romaine et protobyzantine.Oulkeroglou Anastasios, Papadopoulos Stratis. La fouille du terrain Yannopoulos et les établissements de bains à Thasos (IIIe-VIe s.). In: Bulletin de correspondance hellénique. Volume 138, livraison 2, 2014. pp. 467-507
The role of actor associations in understanding the implementation of lean thinking in healthcare
Get PDFPurpose: The importance of networks in effecting the outcomes of change processes is well-established in the literature. Whilst extant literature focuses predominantly on the structural properties of networks, our purpose is to explore the dynamics of network emergence that give rise to the outcomes of process interventions. We show how Actor Network Theory (ANT) may be used as a lens for interrogating the way in which management interventions play out in the complex organisational setting of a UK National Health Service Trust, providing insights for management of process change initiatives. Design/methodology/approach: This is a rich qualitative study in the Pathology Unit of a UK National Health Service Trust, using ANT as the theoretical lens for tracking the emergence and transformation of networks of individuals over the course of a management intervention to promote “lean thinking” for performance improvements.Findings: ANT is useful for explicitly tracking how organisational players shift their positions and network allegiances over time, and identifying objects and actions that are effective in engaging individuals in networks enabling transition to a lean process. It is important to attend to the dynamics of the process of change and devise appropriate timely interventions enabling actors to shift their own positions towards a desired outcome.Research limitations/implications: We make the case for using of theoretical frameworks developed outside the operations management to develop insights for designing process interventions.Originality/value: By understanding the role of shifting networks managers can use timely interventions during the process implementation to facilitate the transition to lean processes: e.g. using demonstrable senior leadership commitment and visual communication.<br/
Author Correction: A shared neural basis underlying psychiatric comorbidity
No full textCorrection to: Nature Medicine. Published online 24 April 2023. In the version of this article initially published, the STRATIFY data also included cohort data from the ESTRA consortium, though this was not acknowledged in the author list and the section in Methods on the Stratify dataset. The Methods are now updated, and the author list is amended to combine the STRATIFY and ESTRA consortium names and to include the following authors: Marina Bobou, M. John Broulidakis, Betteke Maria van Noort, Zuo Zhang, Lauren Robinson, Nilakshi Vaidya, Jeanne Winterer, Yuning Zhang, Sinead King, Hervé Lemaître, Ulrike Schmidt, Julia Sinclair, Argyris Stringaris and Sylvane Desrivières. The STRATIFY and ESTRA consortia are now combined to list Marina Bobou, M. John Broulidakis, Betteke Maria van Noort, Zuo Zhang, Lauren Robinson, Nilakshi Vaidya, Jeanne Winterer, Yuning Zhang, Sinead King, Gareth J. Barker, Arun L. W. Bokde, Hervé Lemaître, Frauke Nees, Dimitri Papadopoulos Orfanos, Ulrike Schmidt, Julia Sinclair, Argyris Stringaris, Henrik Walter, Robert Whelan, Sylvane Desrivières and Gunter Schumann as members, and the IMAGEN consortium is updated to also include Sylvane Desrivières. Affiliations, author contributions and acknowledgements have been updated to reflect the new authorship, and all changes have been made in the HTML and PDF versions of the article
Scour below the toe of breakwaters: Investigation of scour formation through a geometrically open filter configuration located at the toe of a rubble mound breakwater lying upon sand
Get PDFScour formation at the toe of a rubble mound breakwater can lead to abrupt failure. Nowadays, counteraction of scour via geometrically closed filter rules, geotextiles or combinations is the common practice. Alternatively, in specific cases the use of geometrically open filters can save significant amount of time and decrease constructional costs. As a primary step towards this direction, the prediction of scour formation through a geometrically open filter can provide important information. Nevertheless, at this moment the knowledge upon this issue is insufficient and limited. A variety of recommendations occurs in literature, separately for toe design/scour protection and for the application of open filter criteria; however none of the studies treats these subjects combined. Therefore the objective of the present thesis is to get insight into scour formation and development through a breakwater toe lying upon sand and designed as a geometrically open filter. Thereby the research aims in drawing the link between scour characteristics with wave loading and filter configuration properties. In order to accomplish the research objective 2D physical model tests were conducted in the 25m long, 1m deep and 0.6m wide wave flume of DMC, installed in the company’s laboratory. In total, 23 tests were executed with irregular waves (Jonswap spectrum) and by varying wave loading and filter configuration properties. In particular, 5 different filter/base layer combinations were examined and 3 different wave conditions were used to investigate the effects of relative grain diameter, relative filter thickness, grading of filter layer, base layer stability Number and storm duration. Quantification of damage magnitude was accomplished via laser profile measurements of filter and base layer prior and after the execution of each test. Furthermore, wave particle velocity climate was determined via the use of an Electromagnetic Flow Meter (EMS) placed at the center of the toe. Finally, temporal evolution scour was captured through the side glass and was examined by digitizing and analyzing snap-shots from predefined time steps. Test results and observations have revealed the highly spatial character of scour formation. Nevertheless, tests with identical boundary conditions showed a surprising convergence in averaged maximum scour depth magnitude. In addition, in the majority of tests an S-curve erosion/deposition pattern was shaped while erosion started immediately at the downstream side of the box threatening breakwater stability. Equilibrium maximum scour depth was reached for less than half the data set; thus erosion process was still in progress. Based on this, two approaches were developed to investigate temporal evolution of scour. Furthermore, dimensional analysis and literature review have revealed the most important parameters that have significant effect in scour formation; their combination has led to the formation of a prediction tool. However, combination of the results from tests with different base materials would not be possible without the introduction of the base material stability Number (critical Shields’ Number). The derived tool is an empirical expression with limited physical background and range of validity. Additionally, it overestimates maximum scour depth due to a serious model effect; the different buoyancy between filter and base layer that was causing initial damage and damage exaggeration. Nevertheless, it is capable of delineating the relative contribution of each parameter in scour depth formation. For an overall view of scour formation, further research will be needed to provide a more accurate quantification of the interrelation between parameters that play a role in scour formation and development, and to implement the effect of missing parameters. Consequently the use of the derived expression as a scour prediction tool in real life is not yet recommended.Hydraulic EngineeringCivil Engineering and Geoscience
Medical prescriptions in Cyprus.
Get PDFMEDICAL PRESCRIPTIONS IN CYPRUS Author: Papadopoulos V. Philippos Tutor: RNDr. Jana Kotlářová, Ph.D. Department of Social and Clinical Pharmacy, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Czech Republic Aim of diploma thesis is to get: current knowledge about medical prescriptions (MP) in Cyprus and rules of their use their basic division according their kinds, formal look, practical handle, payment knowledge of the current Health system of Cyprus Results: The Health system of Cyprus is a unique arrangement in the EU since is a simultaneous participation of public and the private sector which has many phenomena of inequality and non- accessibility mainly from the economically weaker. In the future plans of Ministry of Health is the complete redesign of entire Health System in a direction of electronic services for all the parts of health system chain including doctors, pharmacists and insured patients. The basic and significant informations about medical prescriptions in Cyprus according aim of diploma thesis are demonstrated in the Summary Table at chapter 11. All prescriptions in Cyprus are in common form for all type of drugs and there is no rule for size and color of the paper. Pharmacist is checking the signature of the doctor as well as name of the patient and..
A probabilistic approach towards an evaluation of existing code provisions for seismically isolated structures (Eccomas Congress 2016)
No full textFollowing modern design codes, seismically isolated superstructures are designed to respond in the elastic response range or to exhibit limited inelastic behavior. However, the behavior of seismically isolated structures when the superstructure enters the inelastic response range has not been extensively investigated in the past. This paper aims at answering the following questions: What is the probability that a (code-compliant) seismically isolated structure will yield? Will it develop a ductility demand μ larger than that implied by its design strength reduction factor? The probabilistic investigation of such a behavior is important for two reasons: First, to estimate the conservativism implied by the existing code provisions for seismically isolated structures. Second, to account for the case in which the seismic forces acting on an existing seismically isolated structure could exceed the design forces due to a ground motion stronger than the design ground motion level. The investigation is conducted using a two-degree-of-freedom model of a seismically isolated structure. The hysteretic behavior of the seismic isolation devices and the isolated superstructure is simulated in Matlab and OpenSees using a bilinear elastic-plastic model. The results are obtained by analyzing the responses of the isolated structure to a large number of recorded ground motions. Fragility curves to estimate the probability that the structure enters the inelastic range (μ>1), if it is designed according to the existing American and European code provisions for seismically isolated structures are determined through probabilistic seismic demand analysis (PSDA). The influence of the isolated structure overstrength and the isolation system hardening is discussed. Additional fragility curves are provided for other values of the engineering demand parameter (EDP) that are not allowed in the existing code provisions (e.g. superstructure displacement ductility μ>2). The effects of seismic isolation and superstructure design parameters on the fragility curves is quantified through parametric analysis.</p
Boronic Acid Group: A Cumbersome False Negative Case in the Process of Drug Design
No full textHerein we present, an exhaustive docking analysis considering the case of autotaxin (ATX). HA155, a small molecule inhibitor of ATX, is co-crystallized. In order to further extract conclusions on the nature of the bond formed between the ligands and the amino acid residues of the active site, density functional theory (DFT) calculations were undertaken. However, docking does not provide reproducible results when screening boronic acid derivatives and their binding orientations to protein drug targets. Based on natural bond orbital (NBO) calculations, the formed bond between Ser/Thr residues is characterized more accurately as a polar covalent bond instead of a simple nonpolar covalent one. The presented results are acceptable and could be used in screening as an active negative filter for boron compounds. The hydroxyl groups of amino acids are bonded with the inhibitor’s boron atom, converting its hybridization to sp3
Anti-symmetric mode excitation and seismic response of base-isolated bridges under asynchronous input motion
Get PDFThis paper investigates the effect of asynchronous earthquake ground motion on the transverse response of base-isolated bridges. In this context, the excitation of anti-symmetric modes of vibration under asynchronous input is examined and is statistically correlated with characteristic engineering demand parameters. Different ground motion scenarios are considered for various combinations of soil class, wave propagation velocity and loss of correlation patterns among different support motions, using a spectral representation method to generate m-variate, fully non-stationary, EC8 spectrum-compatible ground motion vector processes. It is shown that in the idealised case of the wave passage effect only, the detrimental effects of asynchronous excitation are concentrated on the very last piers along the direction of the seismic waves. However, when loss of coherency is also taken into account in a more realistic scenario, the impact of spatial variability is significantly more uniformly distributed. Most importantly, the conditional probability of a detrimental increase in an EDP of interest (i.e., pier base bending moments and deck drift) under multi-support excitation given that an anti-symmetric mode is excited is not only uniform but also considerably high. This is a clear evidence that the local increase of seismic demand in the bridge studied is associated with the excitation of the first anti-symmetric mode of vibration.</p
Study of the induced magnetic field and the electron conjugation of B- and N- heterocycle organic and organometallic compounds
No full textThe first part of this work consists of the theoretical study of the molecular orbitals contribution to the induced magnetic field, in order to investigate the π-aromaticity concept. The theoretical techniques for the calculation of the shielding tensor, , have been developed starting with the standard compounds of the aromatic benzene, antiaromatic cyclobutadiene and non aromatic borazine. The CMO-NICS analysis of the individual molecular orbitals, which has been done not only for the vertical NICS component (NICSzz), but for the isotropic NICS value (NICSiso) as well, showed that in all molecules the fully delocalized molecular orbital has negative NICS(0)zz values. The differentiation among the three molecules is depicted in the NICS(0)zz values of the HOMO molecular orbitals, as in the aromatic benzene the HOMO has a negative NICS(0)zz value, in the antiaromatic cyclobutadiene large positive values, while in the non aromatic borazine has very small positive value. The σ molecular orbitals have the same behavior in the three compounds. The NICS-SCAN analysis, where the NICS values have been calculated in a series of points extended up to 8 Ǻ above the center of the ring with an increment of 0.2 Ǻ, for each molecular orbital, for the total electronic system as well as for the π, σ and core subset of electrons, showed that the differentiation of the three systems is mainly due to the π system. From the values of the chemical shielding tensor calculated in a cube containing the molecule, three dimensional NICS isosurfaces have been cinstructed showing clearly the diatropic and paratropic regions around each molecule. Finally, using the CMO-IMF method a series of visualizations have been constructed, namely the vectors of the IMF, , contour maps of , Bzind, and NICSiso. It has been concluded that these visualizations provide valuable tools for the study of aromaticity. The above methodologies were implemented into the isolectronic to benzene monocyclic azaborines, C4NBH6 και C2N2B2H6, in order to investigate their aromaticity. The CMO-NICS analysis of the three isomers of azaborines of the type C4NBH6 shows that the π system of molecular orbitals, like in benzene, has negative NICS(0)zz values. The HOMO orbitals in these three isomers are diatropic. The σ molecular orbitals with large number of nodal planes are paratropic, whereas those with small number of nodal planes area are diatropic. The isocontour maps of the π molecular orbitals show diatropicity inside the ring plane and paratropicity around it. According to the CMO-NICS and CMO-IMF analyses the 1,3-azaborine isomer has the stronger diatropic character. This has been confirmed from the NBO analysis, as in 1,3-azaborine there is a benzene-like resonance structure, which have the six π electrons allocated in each p atomic orbital of the six atoms, whereas no such resonance structure exists in the other azaborine isomers. The CMO-NICS analysis of the eleven isomers of the azaborines with molecular type C2N2B2H6 showed that the π system has negative NICS(0)zz values. The fully delocalized π molecular orbital has also negative values, whereas the HOMO has positive NICS(0)zz values in 1,4-diaza-2,3-diborine and 1,2-diaza-3,4-diborine isomers. The dissection of chemical shielding tensor of every MO to the sum of four parts, according to GIAO method, revealed that the z component of NICS at the center of the ring, NICS(0)zz, is highly correlated (R2=0,91) with the electronic excitations of the two highest energy occupied π orbitals to unoccupied orbitals. The isocontour maps of the eleven isomers of azaborines depict that the high energy σ molecular orbitals with large number of nodal planes are mainly paratropic. On the contrary, the low energy σ molecular orbitals, with small number of nodal planes, are mainly diatropic inside the ring, having paratropic regions around it. The isocontour maps of the total σ electronic system of these isomers show paratropicity into the center of the ring, diatropicity across the molecular framework and paratropic regions around the ring. The isocontour maps of the π molecular orbitals are mainly diatropic inside the ring and along the molecular framework and they have paratropic regions around the ring. Different response to the magnetic field is depicted in 1,4-diaza-2,3-diborine and in 1,2-diaza-3,4-diborine. In these isomers the HOMO molecular orbitals depict small paratropic regions inside the ring plane. The next study concerns the aromaticity of triphenylene. The CΜΟ-NICS analysis of the π molecular orbitals of triphenylene showed that the NICS(0)zz values of the HOMO molecular orbital are positive in the central ring and negative in the peripheral rings. This indicates that the peripheral rings in triphenylene are responsible for the aromaticity. This conclusion is enforced from the NICS-SCANout diagrams of the central and peripheral rings of triphenylene. The isosurfaces for the out of plane component of NICS, depict diatropic regions along the molecular framework and paratropic regions around it. The diatropic regions are more intense in peripheral rings than in central ring. An analogous study has been carried out for a series of isolectronic to triphenylene BN-hetero systems. The CMO-NICS analysis showed that only in 3,7,11-triboro-4,8,12-triazarotriphenylene the central ring has negative NICS(0)zz values. On the other side, the CMO-NICS analysis of peripheral rings of isomers showed that only the 3,7,11- triboro-4,8,12-triazarotriphenylene και 2,6,10-triboro-4,8,12-triazarotriphenylene show negative NICS(0)zz values. In all isomers, the fully delocalized π molecular orbital has negative NICS(0)zz values, not only for central rings but for peripheral rings as well. Generally the π molecular orbital delocalized in the central ring shows large negative NICS(0)zz values, when the calculation concerns in the central ring, whereas, when the calculation concerns the peripheral ring, these values become less negative and sometimes positive. The NICS-SCANout diagrams of the isomers having nitrogen and boron atoms in “ortho-” positions, appear similarities with borazine’s NICS-SCANout diagrams, not only for peripheral rings, but also for central rings. Thus, it is obvious that the isomers 3,7,11-triboro-4,8,12-triazarotriphenylene and 1,5,9-triboro-2,6,10-triazaro-triphenylene are non aromatic compounds. In 1,5,9- triboro-3,7,11-triazarotriphenylene και 2,6,10-triboro-4,8,12-triazarotriphenylene, having nitrogen and boron atoms in “meta-” positions, the NICS-SCANout diagrams of the peripheral rings, appear similarities with NICS-SCANout diagrams of the triphenylene’s peripheral rings. On the other, the NICS-SCANout diagrams of the central rings appear to be similar to borazine’s NICS-SCANout diagrams. The BN-triphenylene analogues, having nitrogen and boron atoms in “para-” positions, the NICS-SCANout diagrams, appear to be similar to borazine’s NICS-SCANout diagrams for central and peripheral rings too. The isosurfaces of the molecules, having nitrogen and boron atoms in “ortho-” and “para-” positions are more diatropic in the central ring than in peripheral rings. The isomers having nitrogen and boron atoms in “meta-” orientation are diatropic in peripheral rings, and they don’t show response to the external magnetic field in central ring. [...]Στο πρώτο μέρος της διατριβής μελετήθηκε θεωρητικά η συνεισφορά των μοριακών τροχιακών του μορίου στο επαγόμενο μαγνητικό πεδίο, ώστε να διερευνηθεί η έννοια της π-αρωματικότητας. Ξεκινώντας από τα πρότυπα συστήματα του αρωματικού βενζολίου, του αντιαρωματικού κυκλοβουταδιενίου και της μη αρωματικής βοραζίνης, αναπτύχθηκαν οι τεχνικές του θεωρητικού υπολογισμού του τανυστή χημικής προστασίας, , με τη μέθοδο NICS. Αρχικά πραγματοποιήθηκε η ανάλυση CMO-NICS κάθε μοριακού τροχιακού τόσο για την κάθετη στο επίπεδο του δακτυλίου συνιστώσα του NICS (NICSzz), όσο και για την ισοτροπική τιμή του (NICSiso). Προέκυψε ότι το πλήρως απεντοπισμένο μοριακό τροχιακό εμφανίζει αρνητικές τιμές NICS(0)zz και στις τρεις ενώσεις. Στο αρωματικό βενζόλιο το μετωπικό τροχιακό ΗΟΜΟ εμφανίζει μεγάλη αρνητική τιμή NICS(0)zz, στο αντιαρωματικό κυκλοβουταδιένιο εμφανίζει μεγάλες θετικές τιμές και στην μη αρωματική βοραζίνη οι τιμές NICS(0)zz είναι σχεδόν μηδενικές. Τα σ μοριακά τροχιακά και για τις τρεις ενώσεις παρουσιάζουν παρόμοια συμπεριφορά. Στη συνέχεια πραγματοποιηθήκαν θεωρητικοί υπολογισμοί NICS-SCAΝ, δηλαδή υπολογισμοί της τιμής NICS σε απόσταση μέχρι 8 Ǻ πάνω από το κέντρο των δακτυλίων για τα υποσύνολα των π, σ και εσωτερικών ηλεκτρονίων καθώς και για το σύνολο των ηλεκτρονίων τους. Προέκυψε ότι η διαφοροποίηση μεταξύ αρωματικών, αντιαρωματικών και μη αρωματικών ενώσεων οφείλεται στο π σύστημα. Η ίδια ανάλυση πραγματοποιήθηκε και για κάθε μοριακό τροχιακό (ΜΟ-NICS-SCAN). Στην συνέχεια από υπολογισμούς των τιμών του τανυστή χημικής προστασίας στο χώρο που περιβάλλει το μόριο, δημιουργήθηκαν τρισδιάστατες ισοεπιφάνειες των τιμών NICS (Isosurfaces) με στόχο την τρισδιάστατη οπτικοποίηση των περιοχών παρατροπικότητας και διατροπικότητας. Τέλος, χρησιμοποιώντας την τεχνική CMO-IMF οπτικοποιήθηκαν, με τη μορφή ισόπυκνων καμπύλων (Isocontour Maps), τα διανύσματα των μαγνητικών γραμμών, , το μέτρο της έντασης, , του επαγόμενου μαγνητικού πεδίου, η κάθετη στο επίπεδο συνιστώσα του μαγνητικού πεδίου, Bzind, (NICSzz), και η τιμή NICSiso, για καθένα μοριακό τροχιακό, για το υποσύνολο των π, σ και εσωτερικών ηλεκτρονίων, καθώς και για το σύνολο των ηλεκτρονίων των μορίων). Από την όλη μελέτη διαπιστώθηκε ότι οι χρησιμοποιούμενες οπτικοποιήσεις αποτελούν αξιόπιστα εργαλεία για τη μελέτη της αρωματικότητας αυτών των απλών συστημάτων. Επίσης διαπιστώθηκε ότι η σημαντική συμβολή των τροχιακών ΗΟΜΟ στο χαρακτηρισμό ενός μορίου ως αρωματικού, μη αρωματικού ή αντιαρωματικού. Οι παραπάνω τεχνικές εφαρμόστηκαν σε μονοκυκλικά συστήματα αζαβορίνων του τύπου C4NBH6 και C2N2B2H6, που είναι μόρια ισοηλεκτρονικά του βενζολίου, με σκοπό τη διερεύνηση της αρωματικής συμπεριφοράς τους. Η CMO-NICS ανάλυση των τριών αζαβορίνων της μορφής C4NBH6 δείχνει ότι τα π μοριακά τροχιακά έχουν αρνητικές τιμές NICS(0)zz, όπως συμβαίνει και στην περίπτωση του βενζολίου. Τα σ μοριακά τροχιακά μεγάλου αριθμού κομβικών σημείων εμφανίζουν ισχυρή παρατροπική συμπεριφορά, ενώ αυτά με μικρό αριθμό κομβικών σημείων διατροπική συμπεριφορά. Η ανάλυση των τιμών του τανυστή χημικής προστασίας του κάθε ΜΟ σε άθροισμα τεσσάρων όρων, σύμφωνα με τη μέθοδο GIAO, αποκάλυψε ότι, η z συνιστώσα του δείκτη NICS στο κέντρο του δακτυλίου για το σύνολο των ηλεκτρονίων, NICS(0)zz, συσχετίζεται σε μεγάλο βαθμό (R2=0,91) με τις ηλεκτρονιακές διεγέρσεις των δύο υψηλής ενέργειας κατελειμένων π τροχιακών σε μη κατελειμένα τροχιακά. Οι ισόπυκνες καμπύλες των π μοριακών τροχιακών των αζαβορίνων εμφανίζουν διατροπικότητα στο εσωτερικό του δακτυλίου και παρατροπικότητα γύρω από αυτόν. Από την ανάλυση CMO-NICS και CMO-IMF προέκυψε ότι η διατροπική συμπεριφορά της 1,3-αζαβορίνης είναι ισχυρότερη σε σχέση με τα υπόλοιπα δύο ισομερή Αυτό επιβεβαιώνεται και από τις δομές συντονισμού των τριών ισομερών, όπως υπολογίζονται από την ανάλυση NBO. Συγκεκριμένα, η 1,3-αζαβορίνη εμφανίζει μια δομή συντονισμού όπου τα έξι π ηλεκτρόνια του συστήματος κατανέμονται ομοιόμορφα στα 6p τροχιακά όλων των ατόμων, όπως ακριβώς συμβαίνει και στο βενζόλιο. Τέτοιες δομές συντονισμού δεν εμφανίζονται στις ενώσεις των 1,2- και 1,4-αζαβορίνων. Η CMO-NICS ανάλυση των έντεκα ισομερών των αζαβορίνων του τύπου C2N2B2H6 έδειξε ότι στο σύστημα των π μοριακών τροχιακών οι τιμές NICS(0)zz είναι αρνητικές. Ποιο συγκεκριμένα αρνητικές τιμές έχουν όλα τα πλήρως απεντοπισμένα π μοριακά τροχιακά των ισομερών. Τα μετωπικά τροχιακά ωστόσο των ισομερών 1,4-διαζα-2,3-διβορίνης και 1,2-διαζα-3,4-διβορίνης εμφανίζουν θετικές τιμές NICS(0)zz. Οι χάρτες ισόπυκνων καμπύλων των επιμέρους σ μοριακών τροχιακών των ισομερών, δείχνουν ότι τα υψηλότερης ενέργειας τροχιακά, που φέρουν μεγάλο αριθμό κομβικών σημείων, εμφανίζουν κυρίως παρατροπικό χαρακτήρα με ορισμένες διατροπικές περιοχές. [...
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