Διερεύνηση δυνατότητας προσδιορισμού της υγείας εμβρύων μέσω μετρήσεων σε υπερηχογραφήματα

113 σ.Στην παρούσα εργασία παρουσιάζονται, κατ αρχήν, οι παράμετροι που επηρεάζουν την παρατήρηση της κίνησης του εμβρύου, ύστερα από την επιβαλλόμενη εξωτερική διέγερση. Προτείνονται δύο προσεγγίσεις προσδιορισμού της μεταφορικής κίνησης: των μεμονωμένων σημείων και του κέντρου βάρους σε συνδυασμό με την παρακολούθηση του κύριου κεντρικού άξονα αδράνειας για τον προσδιορισμό της περιστροφικής κίνησης. Αναπτύχθηκε αλγοριθμικά ένα εργαλείο που υπολογίζει αφενός το κέντρο βάρους του εμβρύου και της μήτρας, οπότε και προσδιορίζει τη σχετική μετατόπιση, και αφετέρου τη στροφή του κεντρικού άξονα αδράνειας του εμβρύου. Η στατιστική ανάλυση επί των μετρήσεων του εργαλείου αποδεικνύει ότι εάν τα περιγράμματα εμβρύου και μήτρας είναι σαφή και η σημείωση του περιγράμματος ακριβής, το κέντρο βάρους μπορεί να προσδιοριστεί με αρκετά μεγάλη ακρίβεια. Παρουσιάζονται μετρήσεις οι οποίες ελήφθησαν επί τριών περιστατικών, χρησιμοποιώντας μεμονωμένα σημεία και τα κέντρα βάρους (εμβρύου, μήτρας). Αξιολογώντας συγκριτικά τα αποτελέσματα, παρατηρείται σαφής διαφοροποίηση των ταχυτήτων του υγιούς εμβρύου σε σχέση με τις άλλες δύο περιπτώσεις. Το γεγονός αυτό είναι μια σαφής ένδειξη της συσχέτισης της υγείας του εμβρύου και της ταχύτητας κίνησης του εντός του αμνιακού υγρού, όταν αυτό διεγείρεται. Εντούτοις, επειδή ο προσδιορισμός της ταχύτητας της κίνησης αυτής είναι μια πολυπαραμετρική διαδικασία, τα δεδομένα που αξιοποιήθηκαν για τη διεκπεραίωση της παρούσας εργασίας δεν είναι αρκετά ώστε να εξαχθούν ασφαλή πορίσματα. Τέλος, γίνεται παρουσίαση κάποιων δυνατοτήτων για αυτοματοποίηση των διαδικασιών μέτρησης. Είναι σαφές ότι η απαιτούμενη ακρίβεια, λόγω της φύσης του προβλήματος είναι αρκετά μεγάλη, γεγονός που καθιστά τις αυτόματες διαδικασίες αρκετά επισφαλείς. Παρά το γεγονός αυτό, περαιτέρω έρευνα επί του αντικειμένου δύναται να οδηγήσει σε αξιοποιήσιμα αποτελέσματα.Μιχάλης Ν. Μήτρο

Ethnic differences in the quality of the interview process and implications for survey analysis: The case of Indigenous Australians

Comparable survey data on Indigenous and non-Indigenous Australians are highly sought after by policymakers to inform policies aimed at closing ethnic socio-economic gaps. However, collection of such data is compromised by group differences in socio-economic status and cultural norms. We use data from the Household, Income and Labour Dynamics in Australia Survey and multiple-membership multilevel regression models that allow for individual and interviewer effects to examine differences between Indigenous and non-Indigenous Australians in approximate measures of the quality of the interview process. We find that there are both direct and indirect ethnic effects on different dimensions of interview process quality, with Indigenous Australians faring worse than non-Indigenous Australians in all outcomes ceteris paribus . This indicates that nationwide surveys must feature interview protocols that are sensitive to the needs and culture of Indigenous respondents to improve the quality of the survey information gathered from this subpopulation

Parents’ interest in their child’s education and children’s educational outcomes across the life course: does gender matter?

There has been a dearth of research exploring the potentially gendered nature of relationships between parent engagement and children’s educational outcomes across the life course. In order to address this gap, this study drew upon data from the Longitudinal Study of Australian Children and utilised adolescents’ reports of the interest shown by their parents in their learning and education as well as parents’ retrospective reports of the interest shown by their own parents growing up. The interest shown by both mothers and fathers in their child’s education during adolescence was found to be important for children’s self evaluations and, via these, their expectations for future educational attainment. Furthermore, when fathers were perceived as showing little to no interest in the education of their adolescent daughters, as opposed to lots, their daughters were significantly less likely to expect to attain a university qualification in the future. While further research is needed, these findings suggest that fathers’ engagement is important for fostering high educational expectations in adolescent girls

Wave transmission through two-dimensional structures by the hybrid FE/WFE approach

The knowledge of the wave transmission and reflection characteristics in connected two-dimensional structures provides the necessary background for many engineering prediction methodologies. Extensive efforts have previously been exerted to investigate the propagation of waves in two-dimensional periodic structures. This work focuses on the analysis of the wave propagation and the scattering properties of joined structures comprising of two or more plates. The joint is modelled using the finite element (FE) method whereas each (of the joined) plate(s) is modelled using the wave and finite element (WFE) method. This latter approach is based on post-processing a standard FE model of a small segment of the plate using periodic structure theory; the FE model of the segment can be obtained using any commercial/in-house FE package. Stating the equilibrium and continuity conditions at the interfaces and expressing the motion in the plates in terms of the waves in each plate yield the reflection and transmission matrices of the joint. These can then be used to obtain the response of the whole structure, as well as investigating the frequency andincidence dependence for the flow of power in the system

Monitoring exercise-induced muscle fatigue and adaptations: Making sense of popular or emerging indices and biomarkers

Regular exercise with the appropriate intensity and duration may improve an athlete’s physical capacities by targeting different performance determinants across the endurance–strength spectrum aiming to delay fatigue. The mechanisms of muscle fatigue depend on exercise intensity and duration and may range from substrate depletion to acidosis and product inhibition of adenosinetriphosphatase (ATPase) and glycolysis. Fatigue mechanisms have been studied in isolated muscles; single muscle fibers (intact or skinned) or at the level of filamentous or isolated motor proteins; with each approach contributing to our understanding of the fatigue phenomenon. In vivo methods for monitoring fatigue include the assessment of various functional indices supported by the use of biochemical markers including blood lactate levels and more recently redox markers. Blood lactate measurements; as an accompaniment of functional assessment; are extensively used for estimating the contribution of the anaerobic metabolism to energy expenditure and to help interpret an athlete’s resistance to fatigue during high intensity exercise. Monitoring of redox indices is gaining popularity in the applied sports performance setting; as oxidative stress is not only a fatigue agent which may play a role in the pathophysiology of overtraining syndrome; but also constitutes an important signaling pathway for training adaptations; thus reflecting training status. Careful planning of sampling and interpretation of blood biomarkers should be applied; especially given that their levels can fluctuate according to an athlete’s lifestyle and training histories

Reengineering the user: Privacy concerns about personal data on smartphones.

Purpose: This paper aims to discuss the privacy and security concerns that have risen from the permissions model in the Android operating system, along with two shortcomings that have not been adequately addressed. Design/methodology/approach: The impact of the applications’ evolutionary increment of permission requests from both the user’s and the developer’s point of view is studied, and finally, a series of remedies against the erosion of users’ privacy is proposed. Findings: The results of this work indicate that, even though providing access to personal data of smartphone users is by definition neither problematic nor unlawful, today’s smartphone operating systems do not provide an adequate level of protection for the user’s personal data. However, there are several ideas that can significantly improve the situation and mitigate privacy concerns of users of smart devices. Research limitations/implications: The proposed approach was evaluated through an examination of the Android’s permission model, although issues arise in other operating systems. The authors’ future intention is to conduct a user study to measure the user’s awareness and concepts surrounding privacy concerns to empirically investigate the above-mentioned suggestions. Practical implications: The proposed suggestions in this paper, if adopted in practice, could significantly improve the situation and mitigate privacy concerns of users of smart devices. Social implications: The recommendations proposed in this paper would strongly enhance the control of users over their personal data and improve their ability to distinguish legitimate apps from malware or grayware. Originality/value: This paper emphasises two shortcomings of the permissions models of mobile operating systems which, in authors’ view, have not been adequately addressed to date and propose an inherent way for apps and other entities of the mobile computing ecosystem to commit to responsible and transparent practices on mobile users’ privacy