381 research outputs found

    Improving Mobile Video Streaming with Mobility Prediction and Prefetching in Integrated Cellular-WiFi Networks

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    We present and evaluate a procedure that utilizes mobility and throughput prediction to prefetch video streaming data in integrated cellular and WiFi networks. The effective integration of such heterogeneous wireless technologies will be significant for supporting high performance and energy efficient video streaming in ubiquitous networking environments. Our evaluation is based on trace-driven simulation considering empirical measurements and shows how various system parameters influence the performance, in terms of the number of paused video frames and the energy consumption; these parameters include the number of video streams, the mobile, WiFi, and ADSL backhaul throughput, and the number of WiFi hotspots. Also, we assess the procedure's robustness to time and throughput variability. Finally, we present our initial prototype that implements the proposed approach.Comment: 7 pages, 15 figure

    Development and Remodeling of the Vertebrate Blood-Gas Barrier

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    During vertebrate development, the lung inaugurates as an endodermal bud from the primitive foregut. Dichotomous subdivision of the bud results in arborizing airways that form the prospective gas exchanging chambers, where a thin blood-gas barrier (BGB) is established. In the mammalian lung, this proceeds through conversion of type II cells to type I cells, thinning, and elongation of the cells as well as extrusion of the lamellar bodies. Subsequent diminution of interstitial tissue and apposition of capillaries to the alveolar epithelium establish a thin BGB. In the noncompliant avian lung, attenuation proceeds through cell-cutting processes that result in remarkable thinning of the epithelial layer. A host of morphoregulatory molecules, including transcription factors such as Nkx2.1, GATA, HNF-3, and WNT5a; signaling molecules including FGF, BMP-4, Shh, and TFG-βand extracellular proteins and their receptors have been implicated. During normal physiological function, the BGB may be remodeled in response to alterations in transmural pressures in both blood capillaries and airspaces. Such changes are mitigated through rapid expression of the relevant genes for extracellular matrix proteins and growth factors. While an appreciable amount of information regarding molecular control has been documented in the mammalian lung, very little is available on the avian lung

    A new morphometric method for the sella turcica and the hypophyseal fossa and its clinical relevance

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    The sella turcica and the hypophyseal fossa should be considered different entities, the latter being part of the former. Their morphology and dimensions correlate to some extent with those of the contained pituitary gland and have, for this reason, attracted the interest of anatomists and radiologists. With the application of MRI, however, these data are of limited use in the diagnosis of pituitary disorders, although they remain valuable with regard to a microsurgical approach to the hypophysis. The proposed morphometric method was applied to 20 dry skulls. We first made casts of the corresponding sellae. Their volumes were then measured by immersion. The frontal section of each hypophyseal fossa was obtained through its deepest point and magnified. The Cartesian co-ordinates of the contour of the section were used to evaluate the corresponding area and centroid. The volume of each fossa was finally obtained by the use of Pappus’ theorem applied to solids of rotation. The volumes of the sellae obtained as above ranged from 460 mm3 to 1570 mm3 with a mean value of 835 mm3. These figures are comparable to those reported from previous authors. To our knowledge the method described has enabled a close approximation of the volumes of the hypophyseal fossae to be made for the first time. These volumes ranged from 24 mm3 to 300 mm3, with a mean value of 157 mm3. Similar numerical methods might be applicable in vivo by the use of MR imaging

    MINERALOGICAL AND SPECTROSCOPIC STUDY OF NESQUEHONITE SYNTHESIZED BY REACTION OF GASEOUS CO2 WITH MG CHLORIDE SOLUTION

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    Στην παρούσα εργασία πραγματοποιήθηκε η σύνθεση νεσκεχονίτη, ενός ένυδρου ανθρακικού ορυκτού, υπό χαμηλές συνθήκες πίεσης με αντίδραση CO2 σε διάλυμα χλωριούχου μαγνησίου. Ο νεσκεχονίτης μπορεί να αξιοποιηθεί ως πρώτη ύλη σε δομικά υλικά και επιπλέον στην διαχείριση υγρών αποβλήτων. Ο νεσκεχονίτης μελετήθηκε με περιθλασιομετρία ακτίνων-Χ, υπέρυθρη φασματοσκοπία (FT-IR) και φασματοσκοπία Raman, διοφθάλμιο στερεοσκόπιο, Ηλεκτρονικό Μικροσκόπιο Σάρωσης και Ηλεκτρονικό Μικροσκόπιο Διερχόμενης Δέσμης Ηλεκτρονίων. Ο παραγόμενος νεσκεχονίτης αναπτύσσει επιμήκεις διαφανείς έως ημιδιαφανείς βελονοειδείς κρυστάλλους με υαλώδη λάμψη. Η υπέρυθρη φασματοσκοπία (FT-ΙR) και η φασματοσκοπία Raman υπέδειξαν την παρουσία ΟΗ- και HCO3 - στην κρυσταλλική δομή του νεσκεχονίτη. Η διαδικασία σύνθεσης που περιγράφεται στην παρούσα εργασία μπορεί να χρησιμοποιηθεί στην διαδικασία της ορυκτοποίησης για μόνιμη αποθήκευση των εκπομπών CO2Nesquehonite, a hydrous carbonate with promising uses such as building raw material and treatment of wastewaters, was synthesized under low pressure conditions by reaction of gaseous CO2 with Mg chloride solution and it was studied by means of X-Ray Diffraction, optical and scanning/transmission electron microscopy, and FTIR and Raman spectroscopic methods. Synthesized nesquehonite forms elongated fibers, exhibiting transparent to translucent diaphaneity and vitreous luster. It is characterized by high crystallinity. IR and Raman spectroscopy indicated the presence of OHand HCO3 - in the crystal structure of nesquehonite. The nesquehonite synthesis described herein constitutes a potential permanent storage of CO2 emissions

    The Examination of Injuries in Dancers

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    The purpose of the present study was to examine the incidence of the injuries in dancers. A hundred and sixty eight dancers (135 women and 33 men) 23.17+6.43 years old, members of different dancing clubs, participated in the research. All the subjects participated only in dancing programs for learning, performing and practicing in any kind of dance and no other form of physical activity, and filled the instrument of measurements concerning general questions as well as questions about injury incidence. For data analysis, descriptive analysis and Pearson chi-square test of the SPSS version 17 for windows, were used. From the results it was shown that the biggest percentage of dancers take hip-hop (25.1%) and Latin American lessons (18.6%). Moreover, the dancers are involved in European dances, classic ballet, modern dance, oriental dances and Greek dances. The subjects participated in dance programs for 4.44 + 4.45 years, 3.16+1.63 days a week, for 2.29+1.30 hours a day. According to the dancersrsquo statements, 44.62% of them have suffered an injury. The most usual kinds of injuries are muscle strains (22.9%), muscular spasms-cramps (20.15%), callus (13.18%), sprains (12.53%), blisters (11.80%) and abrasions (11.10%). Also, in smaller percentages follow the fractures (3.48%), hematomas (3.48%) and dislocations (1.38%). The most significant causes of the injuries are poor warming-up (21.92%), fatigue (16.64%), clumsiness (15.68%), bad technique (10.48%), and concentration (10%), and nbspin smaller percentages performance pressure (7.12%), shoes (5.2%), partner and floor (4.8% both), hour of the day (1.44%), as well as competition and space tightness (7.96% both). Most of the dancers of the present sample (34%), who had an injury, overcame it with medication, 25% needed further medical examinations and 20% overcame the injury with rehabilitation. 16% of the dancers needed rest, while fortunately, only 5% overcame the injury with a surgery. Finally, most of the dancers of the present sample (63.76%) consider that dance teachers, as well as dancing clubs, are concerned very much with injuries prevention (63.76%). Consequently, recognizing, resolving, but above all, preventing the causes of injuries is very important concerning injuriesrsquo avoidance, good physical condition of dancers, reduction of training time loss, continuation of professional career, and continuation of dancing activity of those who have finished their career or are not professionally engaged in dancing

    NOX5: molecular biology and pathophysiology

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    Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Nox), comprise seven family members (Nox1–Nox5 and dual oxidase 1 and 2) and are major producers of reactive oxygen species in mammalian cells. Reactive oxygen species are crucially involved in cell signalling and function. All Noxs share structural homology comprising six transmembrane domains with two haem‐binding regions and an NADPH‐binding region on the intracellular C‐terminus, whereas their regulatory systems, mechanisms of activation and tissue distribution differ. This explains the diverse function of Noxs. Of the Noxs, NOX5 is unique in that rodents lack the gene, it is regulated by Ca2+, it does not require NADPH oxidase subunits for its activation, and it is not glycosylated. NOX5 localizes in the perinuclear and endoplasmic reticulum regions of cells and traffics to the cell membrane upon activation. It is tightly regulated through numerous post‐translational modifications and is activated by vasoactive agents, growth factors and pro‐inflammatory cytokines. The exact pathophysiological significance of NOX5 remains unclear, but it seems to be important in the physiological regulation of sperm motility, vascular contraction and lymphocyte differentiation, and NOX5 hyperactivation has been implicated in cardiovascular disease, kidney injury and cancer. The field of NOX5 biology is still in its infancy, but with new insights into its biochemistry and cellular regulation, discovery of the NOX5 crystal structure and genome‐wide association studies implicating NOX5 in disease, the time is now ripe to advance NOX5 research. This review provides a comprehensive overview of our current understanding of NOX5, from basic biology to human disease, and highlights the unique characteristics of this enigmatic Nox isoform

    The development of the spiral ganglion in the human foetus

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    The development of the spiral ganglion was studied in steps sections of 81 human temporal bones. By the 8th week, the spiral ganglion has already separated from the vestibular ganglion. At 13 weeks two distinct populations are observed that correspond to neuron and Schwann cells. At 15 weeks the spiral ganglion has increased its distance from the cochlear duct and is surrounded by mesenchyme near the scala tympani. At 14 weeks a gradual decrease in the nucleus-to-cell area ratio was observed in spiral ganglion neurons that may reflect a morphological adaptation to function. By the 23rd week the modiolus begins to ossify and the spiral ganglion is surrounded by bony trabeculae. The time course of spiral ganglion development follows that of the stria vascularis and organ of Corti, although maturation changes are still observed in the neuronal population even beyond 20 weeks
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