Investigating the Efficiency of Senior Secondary Schools: Evidence from Schools in the Greek region of Central Macedonia

Purpose: This study examines the efficiency of Senior Secondary Schools, in the Region of Central Macedonia in Greece, using input-oriented Data Envelopment Analysis, with three inputs and two outputs variables. Data concern schools in urban, semi-urban/rural, for the school years 2007-08 (before the economic crisis) and 2010-11 (during the economic crisis). Design/methodology/approach: In this study, Data Envelopment Analysis is applied under the Constant Returns to Scale (CRS) or Variable Returns to Scale (VRS) hypotheses. The study used a Senior Secondary Schools sample with stratified proportional sampling. This study’s data collection has been accomplished with the help of the information systems and the databases maintained in every school. Findings: The empirical analysis revealed that the majority of schools were inefficient. The technical efficiency under constant returns to scale varies in interval [0.510-1] and [0.511-1], with average score being 0.729 and 0.827, for the school years 2007-08 and 2010-11, respectively. Under variable returns to scale varies in interval [0.521-1] and [0.516-1], with average efficiency score being 0.815 and 0.834, for the school years 2007-08 and 2010-11, respectively. The scale efficiency for 2007-08 varies in interval [0.673-1], for 2010-11 varies in interval [0.939-1], with average efficiency score being 0.897 and 0.991, respectively. During the economic crisis the performance of schools improved. Additionally, the schools in semi-urban/rural areas had on average higher efficiency than those in urban areas. Research limitations/implications: Further research can extend this study. For instance, future studies could introduce additional input and output variables. Moreover, researchers might use a combination of available techniques such as bootstrapping to estimate the efficiency of schools over a longer period of time and after the economic crisis. Originality/value: To the best of our knowledge, this is the first study of the aforementioned issue for a region on the European Union’s periphery one year before and one year during the economic crisis. The results are expected to provide insightful information for policymakers in order to better understand the performance of the schools and seek more appropriate solutions aiming at moving the sector forward. The proposal of this study is the establishment of an Observatory, authored by the Greek Ministry of Education, monitoring the diachronic data and measurements of the schools’ efficiency

Surfactant proteins SP-A and SP-D modulate uterine contractile events in ULTR myometrial cell line

Pulmonary surfactant proteins SP-A and SP-D are pattern recognition innate immune molecules. However, there is extrapulmonary existence, especially in the amniotic fluid and at the feto-maternal interface. There is sufficient evidence to suggest that SP-A and SP-D are involved in the initiation of labour. This is of great importance given that preterm birth is associated with increased mortality and morbidity. In this study, we investigated the effects of recombinant forms of SP-A and SP-D (rhSP-A and rhSP-D, the comprising of trimeric lectin domain) on contractile events in vitro, using a human myometrial cell line (ULTR) as an experimental model. Treatment with rhSP-A or rhSP-D increased the cell velocity, distance travelled and displacement by ULTR cells. rhSP-A and rhSP-D also affected the contractile response of ULTRs when grown on collagen matrices showing reduced surface area. We investigated this effect further by measuring contractility-associated protein (CAP) genes. Treatment with rhSP-A and rhSP-D induced expression of oxytocin receptor (OXTR) and connexin 43 (CX43). In addition, rhSP-A and rhSP-D were able to induce secretion of GROα and IL-8. rhSP-D also induced the expression of IL-6 and IL-6 Ra. We provide evidence that SP-A and SP-D play a key role in modulating events prior to labour by reconditioning the human myometrium and in inducing CAP genes and pro-inflammatory cytokines thus shifting the uterus from a quiescent state to a contractile one

Innate immune molecules in preterm birth and disease

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonPreterm labour is one of the leading causes of perinatal mortality and morbidity. Most premature babies die before the age of five, and if they survive they face a high risk of disabilities and impairments. SP-A and SP-D are pattern recognition, innate immune molecules that are responsible for the maintenance of pulmonary immunity and surfactant homeostasis. They have been localised in the human reproductive tract and implicated in pregnancy and the initiation of labour. We hypothesised that SP-A and SP-D could play an active role in the activation of the myometrium and the timing of parturition. In this study we investigated the effects of the recombinant forms of SP-A and SP-D (rhSP-A and rhSP-D) on contractile events in the myometrium. We validated the expression of surfactant proteins A and D in the in vitro model of myometrium cell line, ULTR, using qPCR, immunofluorescence and ImageStream technology. We demonstrate that rhSP-A and rhSP-D treatments led to an increase in cell motility and had an effect on the contractile response of ULTR cells when grown on collagen matrices showing reduced surface area. We studied this effect further by measuring the expression of contraction-associated protein genes. rhSP-A and rhSP-D led to an increase in the expression of oxytocin receptor and connexin 43. We reported that both rhSP-A and rhSP-D induce the secretion of pro-inflammatory cytokines, such as IL-6 and IL-8. We also propose a new model for functional progesterone withdrawal showing a cross-talk between progesterone (including non-genomic effects) and SP-A. Emerging evidence has linked shredding of the uterine wall with ovarian cancer cases, suggestive of an interaction between myometrium and ovaries. We investigated the effects of rhSP-D in ovarian cancer in vitro using SKOV3 cells as a model. Conditioned media from ULTRs treated with rhSP-D resulted in growth arrest of SKOV3. We also demonstrated that rhSP-D led to a decrease in cell motility and cell proliferation in these cells. This was followed by an inhibition of the mTOR pathway activity. We expanded on our observations by measuring expression of SP-A and SP-D in human myometrial samples as well as the expression of SP-D in human ovaries. Collectively, this study presents novel interactions of SP-A and SP-D at both myometrial and ovarian level, rendering them key molecules for conditions such as preterm labour as well as implicating them as therapeutic targets for ovarian cancer

Asphalt transport pavements : causes of deterioration, methods of maintenance and suggestions/guidelines for new smart methods

The pavements have developed in recent decades, as studies have introduced new materials in their construction, such as types of asphalt, new standard sizing and new requirements for the surface characteristics. The surface characteristics, namely the critical contact surface with vehicle tires, is able to deliver higher quality, speed and travel comfort without compromising the integrity of mobile vehicles and their passengers. The pavement, as a construction element, is inextricably linked with the road transport systems, since essentially the supporting structure, which is responsible for the movement of vehicles. Modern technology has brought great improvement to the durability, quality and safety of road surfaces with the use of new materials and construction techniques The provision of permanent deformation is necessary both during the design phase and construction and during the operation phase of a pavement. It explores the impact of factors affecting development and can provide valuable information on the behavior of road against traffic loads. This allows the better management of the road network. The study presents the types of deformation found in asphalt pavements, as well as a number of types of maintenance, along with new ideas and suggested solutions from abroad.Complete

Non - destructive testing for the study of damage accumulation of glass - fiber reinforced polymers (GFRP's), with and without the addition of carbon nanotubes

Multi wall carbon nanotubes were used as an additive in the matrix of glass / vinylester composites, in order to improve their damage tolerance and provide a means for their damage assessment at any stage of their loading history. The improvement of the damage tolerance is expected to stem from the incorporation of an additional interfacial area that activates energy dissipation mechanisms such as interfacial sliding, fibre pull out and bridging as well as crack bifurcation and arrest; all these mechanisms are active at the nanoscale. The life monitoring is performed via the electrical resistance changes in the conductive carbon nanotube network within the composite matrix; this network follows any deformation of the composite providing real time strain monitoring and, at the same time, pinpoints all loci of failure through the local breach of the conductive path that lead to a monotonic increase in the overall resistance. The experimental findings verify both the increased damage tolerance of the doped composites and the reliable damage assessment of the composite at all stages of its loading history. Other Non - Destructive Techniques were utilized in order to detect and quantify the accumulating damage. Inverse scattering theory and phase velocity data were used in order to determine the elastic constants of the stifness matrix of the anisotropic material. Fracture toughness and fatigue life behaviour were investigated for both the material systems.Τα σύνθετα υλικά οργανικής μήτρας ενισχυμένα με ίνες γυαλιού είναι μια κατηγορία υλικών που έχει υψηλό τεχνολογικό ενδιαφέρον τις τελευταίες δεκαετίες με πληθώρα εφαρμογών στην αεροπορική και διαστημική βιομηχανία, στην αυτοκινητοβιομηχανία, στη formula 1, στα σπορ και γενικότερα όπου οι απαιτήσεις για υψηλή επίδοση των υλικών συνδυάζονται με την απαίτηση για χαμηλό βάρος. Στην κατεύθυνση αυτή έχει συντελέσει και το διαρκώς μειούμενο κόστος παραγωγής των υλικών αυτών μέσω της χρήσης καινοτόμων τεχνικών. Η συνεχής εξέλιξη των υλικών αυτών οδηγεί σε βελτιωμένα υλικά ενισχυτικής και μητρικής φάσης αλλά και εντελώς καινούρια υλικά και προσεγγίσεις όπως είναι ενισχυτικές φάσεις στη νανοκλίμακα (nanofibers, nanotubes). Η εισαγωγή τέτοιων υλικών στη μήτρα συνθέτων υλικών αλλάζει τις μηχανικές και φυσικές τους ιδιότητες με τρόπο πολλές φορές ολοκληρωτικό. Είναι προφανές ότι η τεκμηριωμένη γνώση και ανάπτυξη μεθόδων μη καταστροφικού ελέγχου της δομικής ακεραιότητας αλλά και η γνώση της μηχανικής συμπεριφοράς μέσω της διαδικασίας εξέλιξης της βλάβης σε μια κατηγορία υλικών με τόσο σημαντικές εφαρμογές είναι ζητούμενο από την ερευνητική κοινότητα παγκοσμίως. Προς αυτήν την κατεύθυνση είναι και η συμβολή της παρούσας διατριβής. Μη καταστροφικές μέθοδοι και δοκιμές εφαρμόζονται εδώ και πολλά χρόνια σε σύνθετα υλικά οργανικής μήτρας με επιτυχία παρά την εγγενή ανομοιογένεια και ανισοτροπία που παρουσιάζουν. Ωστόσο πάντα παραμένει ισχυρή η ζήτηση για μεθόδους που θα βοηθήσουν προς την κατεύθυνση της αύξησης της αξιόπιστης χρήσης των υλικών αυτών μέσω της διαρκούς αποτίμησης και γνώσης της φέρουσας ικανότητάς τους. Η συσσώρευση της βλάβης σε σύνθετα υλικά οργανικής μήτρας που υπόκεινται σε μηχανική φόρτιση είναι ένα ζήτημα που έχει διερευνηθεί εκτενώς μέχρι σήμερα. Ωστόσο, η εισαγωγή ενίσχυσης (carbon nanotubes, CNT) στη μήτρα αλλάζει τους μηχανισμούς δημιουργίας και εξέλιξής της. Επίσης προστίθεται η δυνατότητα της μέτρησης μιας ιδιότητας που εμφανίζεται ως αποτέλεσμα της εισαγωγής αυτής και η οποία είναι η ηλεκτρική αγωγιμότητα. Ο βασικός λοιπόν σκοπός της εργασίας αυτής είναι η μελέτη της χρήσης μη καταστροφικών ελέγχων κατά τη διάρκεια μηχανικών δοκιμών συσσώρευσης βλάβης στα υλικά αυτά, καθώς επίσης και η εισαγωγή της μέτρησης της ηλεκτρικής αντίστασης τους ως ικανής μεθόδου παρακολούθησης και ποσοτικοποίησης της βλάβης αυτής. Η διερεύνηση της επιβελτίωσης των μηχανικών ιδιοτήτων λόγω της εισαγωγής των CNT στα υλικά αυτά μέσω της σύγκρισης με τις ιδιότητες που έχουν χωρίς την προσθήκη αυτή. Αναλυτικότερα οι στόχοι που επιδιώξαμε να πετύχουμε στα πλαίσια της διατριβής είναι οι ακόλουθοι: • Μελέτη της διεθνούς βιβλιογραφίας στα συγκεκριμένα θέματα. • Εκτέλεση ειδικά επιλεγμένων μηχανικών δοκιμών σε σύνθετα υλικά Glass/vinylester και Glass/vinylester με CNT (κυκλικά πειράματα φόρτισης – αποφόρτισης – επαναφόρτισης). • Χρήση εξελιγμένων μη καταστροφικών μεθόδων όπως η χρήση δεδομένων ταχύτητας διάδοσης υπερηχητικών ελαστικών κυμάτων (UT) και η ακουστική εκπομπή (AE) για την παρακολούθηση της βλάβης κατά τη διάρκεια των μηχανικών δοκιμών. • Διερεύνηση καταγραφών ηλεκτρικής αντίστασης ως δείκτη βλάβης του υλικού. • Δοκιμές θραυστομηχανικής συμπεριφοράς για την εκτίμηση της βελτίωσης των επιδόσεων του υλικού παρουσία των CNT

Analog Realization of Fractional-Order Skin-Electrode Model for Tetrapolar Bio-Impedance Measurements

This work compares two design methodologies, emulating both AgCl electrode and skin tissue Cole models for testing and verification of electrical bio-impedance circuits and systems. The models are based on fractional-order elements, are implemented with active components, and capture bio-impedance behaviors up to 10 kHz. Contrary to passive-elements realizations, both architectures using analog filters coupled with adjustable transconductors offer tunability of the fractional capacitors’ parameters. The main objective is to build a tunable active integrated circuitry block that is able to approximate the models’ behavior and can be utilized as a Subject Under Test (SUT) and electrode equivalent in bio-impedance measurement applications. A tetrapolar impedance setup, typical in bio-impedance measurements, is used to demonstrate the performance and accuracy of the presented architectures via Spectre Monte-Carlo simulation. Circuit and post-layout simulations are carried out in 90-nm CMOS process, using the Cadence IC suite

Analog Gaussian Function Circuit: Architectures, Operating Principles and Applications

This review paper explores existing architectures, operating principles, performance metrics and applications of analog Gaussian function circuits. Architectures based on the translinear principle, the bulk-controlled approach, the floating gate approach, the use of multiple differential pairs, compositions of different fundamental blocks and others are considered. Applications involving analog implementations of Machine Learning algorithms, neuromorphic circuits, smart sensor systems and fuzzy/neuro-fuzzy systems are discussed, focusing on the role of the Gaussian function circuit. Finally, a general discussion and concluding remarks are provided

A Low-Power Analog Integrated Implementation of the Support Vector Machine Algorithm with On-Chip Learning Tested on a Bearing Fault Application

A novel analog integrated implementation of a hardware-friendly support vector machine algorithm that can be a part of a classification system is presented in this work. The utilized architecture is capable of on-chip learning, making the overall circuit completely autonomous at the cost of power and area efficiency. Nonetheless, using subthreshold region techniques and a low power supply voltage (at only 0.6 V), the overall power consumption is 72 μW. The classifier consists of two main components, the learning and the classification blocks, both of which are based on the mathematical equations of the hardware-friendly algorithm. Based on a real-world dataset, the proposed classifier achieves only 1.4% less average accuracy than a software-based implementation of the same model. Both design procedure and all post-layout simulations are conducted in the Cadence IC Suite, in a TSMC 90 nm CMOS process

Nanopower Integrated Gaussian Mixture Model Classifier for Epileptic Seizure Prediction

This paper presents a new analog front-end classification system that serves as a wake-up engine for digital back-ends, targeting embedded devices for epileptic seizure prediction. Predicting epileptic seizures is of major importance for the patient’s quality of life as they can lead to paralyzation or even prove fatal. Existing solutions rely on power hungry embedded digital inference engines that typically consume several µW or even mW. To increase the embedded device’s autonomy, a new approach is presented combining an analog feature extractor with an analog Gaussian mixture model-based binary classifier. The proposed classification system provides an initial, power-efficient prediction with high sensitivity to switch on the digital engine for the accurate evaluation. The classifier’s circuit is chip-area efficient, operating with minimal power consumption (180 nW) at low supply voltage (0.6 V), allowing long-term continuous operation. Based on a real-world dataset, the proposed system achieves 100% sensitivity to guarantee that all seizures are predicted and good specificity (69%), resulting in significant power reduction of the digital engine and therefore the total system. The proposed classifier was designed and simulated in a TSMC 90 nm CMOS process, using the Cadence IC suite

A Hand Gesture Recognition Circuit Utilizing an Analog Voting Classifier

Electromyography is a diagnostic medical procedure used to assess the state of a muscle and its related nerves. Electromyography signals are monitored to detect neuromuscular abnormalities and diseases but can also prove useful in decoding movement-related signals. This information is vital to controlling prosthetics in a more natural way. To this end, a novel analog integrated voting classifier is proposed as a hand gesture recognition system. The voting classifiers utilize 3 separate centroid-based classifiers, each one attached to a different electromyographic electrode and a voting circuit. The main building blocks of the architecture are bump and winner-take-all circuits. To confirm the proper operation of the proposed classifier, its post-layout classification results (91.2% accuracy) are compared to a software-based implementation (93.8% accuracy) of the same voting classifier. A TSMC 90 nm CMOS process in the Cadence IC Suite was used to design and simulate the following circuits and architectures