Gravity currents in a valley of trapezoidal shape

River hydrodynamicsUnsteady open channel flow and dam brea

Gravity Currents in a Vegetated Valley of Trapezoidal Shape

In this study lock-exchange experiments are performed in a tank of rectangular upper cross section and a lower vegetated valley of trapezoidal shape to study the effect of drag resistance, due to vegetation, on gravity currents. Many natural and man-made channels are approximately trapezoidal. For the simulation of the vegetation the bed is covered by flexible grass vegetation (height of vegetation, hv=2.0cm) of different submergence ratio hν/H (hν=height of vegetation, H=water depth). The motion of the gravity current is monitored with a digital video of high definition, the front velocity is measured and the height of the front is captured. Twenty four experiments are performed, twelve inside the trapezoidal section (H/Htr=0.4, 0.6 or 0.8) and twelve over the trapezoidal section (H/Htr=1.2, 1.4 or 1.6). The initial Reynolds number, based on the height of the valley and the reduced gravity, is greater than 10000 for all cases indicating that the gravity currents are turbulent. Results are compared with those of similar experiments without vegetation (Keramaris and Prinos, 2010) and hence the effect of the vegetation drag resistance on the motion of the current is investigated. The main conclusion of this study is that the shape of the tank plays a significant role in the propagation of gravity currents. The presence of trapezoidal increases the velocity of gravity currents in comparison with triangular or orthogonal shape

Ενδυνάμωση πολιτειότητας μέσα από το μάθημα της Φυσικής Αγωγής: Η περίπτωση της διοργάνωσης Ligue Leonin

Η παρούσα ερευνητική έρευνα δράσης αφορά στη διερεύνηση της βελτίωσης των σχέσεων των μαθητών/τριών της πρωτοβάθμιας εκπαίδευσης, μέσα από δράσεις συμμετοχικής πολιτειότητας και του συμμετοχικού σχεδιασμού project εργασίας που άπτονται του αντικειμένου της Φυσικής Αγωγής. Συγκεκριμένα, πρόκειται για τον ανασχεδιασμό ενός υφιστάμενου πρωταθλήματος ποδοσφαίρου και πετοσφαίρισης, με συμμετοχικό τρόπο από τους μαθητές της Δ’ Δημοτικού της Λεοντείου Σχολής Αθηνών. Έχοντας ως δεδομένο, από προσωπική παρατήρηση αλλά και από επισημάνσεις του συνόλου των εκπαιδευτικών του συλλόγου διδασκόντων, το γεγονός της αυξανόμενης έντασης μεταξύ των μαθητών/τριών από τη συμμετοχή τους στο εσωτερικό πρωτάθλημα, προέκυψε το παρόν ερευνητικό ερώτημα που αφορά στη διερεύνηση για το αν ο ενεργός ρόλος των μαθητών/τριών στην επανασχεδίαση του συγκεκριμένου πρωταθλήματος, μπορεί να βελτιώσει τις σχέσεις των μαθητών/τριών στο σχολικό περιβάλλον. Σε δεύτερο επίπεδο διερευνάται αν ο συμμετοχικός τρόπος αναδιοργάνωσης του πρωταθλήματος αυτού και η δοκιμαστική εφαρμογή του μπορεί να ενισχύσει την καλλιέργεια της παιδείας για την πολιτειότητα αφού το συγκεκριμένο τμήμα της Δ’ Δημοτικού κλήθηκε να ενεργήσει ως μία ομάδα «πολιτών» εντός του σχολικού χώρου.This action research regards the investigation of the improvement of the relations of the students / three of the primary education, through participatory citizenship actions and the participatory planning of project work related to the object of Physical Education. Specifically, it is about the redesign of an existing football and volleyball championship, in a participatory way involving the students of the 4th Elementary School of the Leontios School of Athens. During this championship, the students after each game showed an ongoing tension. That fact inspired me to arose the main subject in my research as to whether the active role of students in the redesign of this championship, can improve the relations between them in the school environment. Furthermore, the participatory method used in the classroom can be a dynamic tool that will lead the students to the understanding of their role as a citizen within the school community

ΜΕΤΡΗΣΕΙΣ ΤΥΡΒΩΔΟΥΣ ΡΟΗΣ ΣΕ ΑΝΟΙΚΤΟ ΑΓΩΓΟ ΔΙΑΠΕΡΑΤΟΥ ΠΥΘΜΕΝΑ ΜΕ ΑΝΕΜΟΜΕΤΡΙΑ ΘΕΡΜΟΥ ΦΙΛΜ

Στην  εργασία  αυτή  διερευνάται  εργαστηριακά  η  τυρβώδης  ροή  σε ανοικτό  αγωγό  με  διαπερατό  πυθμένα  με  τη  χρήση  ανεμομετρίας  θερμού  φιλμ (hot-film). Ο διαπερατός πυθμένας  προσομοιώνεται με πορώδη φίλτρα πορώδους ε  ίσου με 0.70  και 0.91.  Το  σχετικό  πάχος  πορώδους s΄/h (s΄=πάχος  πορώδους, h=συνολικό βάθος ροής πάνω και μέσα από το πορώδες στρώμα) μεταβάλλεται από 0.375 έως 0.5. Μετρήσεις  της  παροχής,  μέσης  ταχύτητας  και  τυρβωδών  μεγεθών (ένταση  τύρβης, τάσεις Reynolds) φανερώνουν την επίδραση των παραπάνω μεγεθών (ε και s΄/h)  στα χαρακτηριστικά της ροής και στην παροχετευτική ικανότητα του αγωγού.Turbulent flow in an open channel with a permeable bed is investigated experimentally with the use of hot-film anemometry. The permeable bed is simulated with porous filters of porosity  ε equal to 0.70 and 0.91. The relative thickness of the porous layer s΄/h (s΄=porous thickness, h=total flow depth over and through porous layer) varies between 0.375 and 0.5. Measurements of discharge, mean velocity and turbulence characteristics (turbulence intensity, Reynolds stresses) indicate the effect of ε and s΄/h on the flow characteristics and the discharge capacity of the channel.

COMPUTATION OF OPTIMUM WATER COURSE FLOW VELOCITY FOR THE SUSTAINABLE OPERATION OF A FISH REFUGE LATERALLY TO THE FLOW

Στην εργασία πραγματοποιήθηκαν εργαστηριακές μετρήσεις και ανάπτυξη μαθηματικών μοντέλων κυκλοφορίας και μεταφοράς συντηρητικού αιωρήματος για τον υπολογισμό της βέλτιστης ταχύτητας ροής υδατορεύματος για τη βιώσιμη λειτουργία ιχθυοδεξαμενής παράπλευρα της ροής, όπως εμφανίζεται στο ποτάμιο περιβάλλον με τις φυσικές ή τεχνητές δεξαμενές ιχθυοπληθυσμών παράπλευρα στην ροή του κύριου ρεύματος. Τα αποτελέσματα δείχνουν ότι όσον αφορά την παγίδευση αιωρουμένων στην ιχθυοδεξαμενή η καλύτερη περίπτωση (μικρότερη παγίδευση) είναι αυτή στην οποία η ταχύτητα του κυρίου ρεύματος είναι περίπου 0.30 m/s, η οποία βρίσκεται σε συμφωνία με την βέλτιστη ταχύτητα συνθηκών διαβίωσης των ψαριών.In this study the development of mathematical models of hydrodynamic circulation and matter transport and laboratory measurements for the computation of optimum watercourse flow velocity for the sustainable operation of a natural or artificial fish refuge laterally to the main riverine low were held. Concerning the trapping of the suspended particles in the fish reservoir, the results show, that the best case (with the minor trapping) corresponds to flow velocity of the main stream approximately 0.30 m/s, which is in very good agreement with the optimal living conditions of the fishes

Burnout and training satisfaction of medical residents in Greece: will the European Work Time Directive make a difference?

<p>Abstract</p> <p>Background</p> <p>The aim of this study is to determine the prevalence of burnout in Greek medical residents, investigate its relationship with training satisfaction during residency and survey Greek medical residents' opinion towards the European Work Time Directive (EWTD).</p> <p>Methods</p> <p>A Multi-centre, cross-sectional survey of Greek residents was performed. The Maslach Burnout Inventory (MBI) was used to measure burnout, which was defined as high emotional exhaustion, combined with high depersonalization or low personal accomplishment. In addition, seven questions were designed for this study to evaluate self-reported resident training satisfaction and three questions queried residents' opinion on the EWTD and its effects on their personal and social life as well as their medical training. Univariate, bivariate and multivariate statistical models were used for the evaluation of data.</p> <p>Results</p> <p>Out of 311 respondents (77.8% response rate), 154 (49.5%) met burnout criteria and 99 (31.8%) indicated burnout on all three subscale scores. The number of residents that were dissatisfied with the overall quality of their residency training were 113 individuals (36.3%). Only 32 residents (10.3%) believed that the EWTD implementation will not have any beneficial effects for them.</p> <p>Conclusions</p> <p>Both burnout and training dissatisfaction were common among Greek residents. Systemic interventions are thus required within the Greek health system, aimed at reducing resident impairment due to burnout and at improving their educational and professional perspectives. Although residents' opinion on the EWTD was not associated with burnout levels, the EWTD was found to be predominantly supported and anticipated by Greek residents and should be implemented to alleviate their workload and stress.</p

Calpains mediate p53 activation and neuronal death evoked by DNA damage.

DNA damage is an initiator of neuronal death implicated in neuropathological conditions such as stroke. Previous evidence has shown that apoptotic death of embryonic cortical neurons treated with the DNA damaging agent camptothecin is dependent upon the tumor suppressor p53, an upstream death mediator, and more distal death effectors such as caspases. We show here that the calcium-regulated cysteine proteases, calpains, are activated during DNA damage induced by camptothecin treatment. Moreover, calpain deficiency, calpastatin expression, or pharmacological calpain inhibitors prevent the death of embryonic cortical neurons, indicating the important role of calpain in DNA damage-induced death. Calpain inhibition also significantly reduced and delayed the induction of p53. Consistent with the actions of calpains upstream of p53 and the proximal nature of p53 death signaling, calpain inhibition inhibited cytochrome c release and DEVD-AFC cleavage activity. Taken together, our results indicate that calpains are a key mediator of p53 induction and consequent caspase-dependent neuronal death due to DNA damage

Adeno-Associated Virus-Mediated Overexpression of LARGE Rescues α-Dystroglycan Function in Dystrophic Mice with Mutations in the Fukutin-Related Protein

Multiple genes (e.g., POMT1, POMT2, POMGnT1, ISPD, GTDC2, B3GALNT2, FKTN, FKRP, and LARGE) are known to be involved in the glycosylation pathway of α-dystroglycan (α-DG). Mutations of these genes result in muscular dystrophies with wide phenotypic variability. Abnormal glycosylation of α-DG with decreased extracellular ligand binding activity is a common biochemical feature of these genetic diseases. While it is known that LARGE overexpression can compensate for defects in a few aforementioned genes, it is unclear whether it can also rescue defects in FKRP function. We examined adeno-associated virus (AAV)-mediated LARGE or FKRP overexpression in two dystrophic mouse models with loss-of-function mutations: (1) Largemyd (LARGE gene) and (2) FKRPP448L (FKRP gene). The results agree with previous findings that overexpression of LARGE can ameliorate the dystrophic phenotypes of Largemyd mice. In addition, LARGE overexpression in the FKRPP448L mice effectively generated functional glycosylation (hyperglycosylation) of α-DG and improved dystrophic pathologies in treated muscles. Conversely, FKRP transgene overexpression failed to rescue the defect in glycosylation and improve the phenotypes of the Largemyd mice. Our findings suggest that AAV-mediated LARGE gene therapy may still be a viable therapeutic strategy for dystroglycanopathies with FKRP deficiency

Adeno-associated Virus 9 Mediated FKRP Gene Therapy Restores Functional Glycosylation of α-dystroglycan and Improves Muscle Functions

Mutations in the FKRP gene are associated with a wide range of muscular dystrophies from mild limb-girdle muscular dystrophy (LGMD) 2I to severe Walker–Warburg syndrome and muscle-eye-brain disease. The characteristic biochemical feature of these diseases is the hypoglycosylation of α-dystroglycan (α-DG). Currently there is no effective treatment available. In this study, we examined the adeno-associated virus serotype 9 vector (AAV9)-mediated gene therapy in the FKRP mutant mouse model with a proline to leucine missense mutation (P448L). Our results showed that intraperitoneal administration of AAV9-FKRP resulted in systemic FKRP expression in all striated muscles examined with the highest levels in cardiac muscle. Consistent with our previous observations, FKRP protein is localized in the Golgi apparatus in myofibers. Expression of FKRP consequently restored functional glycosylation of α-DG in the skeletal and cardiac muscles. Significant improvement in dystrophic pathology, serum creatine kinase levels and muscle function was observed. Only limited FKRP transgene expression was detected in kidney and liver with no detectable toxicity. Our results provided evidence for the utility of AAV-mediated gene replacement therapy for FKRP-related muscular dystrophies

Cataloging and organizing p73 interactions in cell cycle arrest and apoptosis

We have compiled the p73-mediated cell cycle arrest and apoptosis pathways. p73 is a member of the p53 family, consisting of p53, p63 and p73. p73 exists in several isoforms, presenting different domain structures. p73 functions not only as a tumor suppressor in apoptosis but also as differentiator in embryo development. p53 mutations are responsible for half of the human cancers; p73 can partially substitute mutant p53 as tumor suppressor. The pathways we assembled create a p73-centered network consisting of 53 proteins and 176 interactions. We clustered our network into five functional categories: Upregulation, Activation, Suppression, Transcriptional Activity and Degradation. Our literature searches led to discovering proteins (c-Jun and pRb) with apparent opposing functional effects; these indicate either currently missing proteins and interactions or experimental misidentification or functional annotation. For convenience, here we present the p73 network using the molecular interaction map (MIM) notation. The p73 MIM is unique amongst MIMs, since it further implements detailed domain features. We highlight shared pathways between p53 and p73. We expect that the compiled and organized network would be useful to p53 family-based studies