381 research outputs found
Improving Mobile Video Streaming with Mobility Prediction and Prefetching in Integrated Cellular-WiFi Networks
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
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
Recommended from our members
The effect of financial leverage on real and accrual-based earnings management
Past research has documented a substitution effect between real earnings management (RM) and accrual-based earnings management (AM), depending on relative costs. This study contributes to this research by examining whether levels of (and changes in) financial leverage have an impact on this empirically documented trade-off. We hypothesise that in the presence of high leverage, firms that engage in earnings manipulation tactics will exhibit a preference for RM due to a lower possibility—and subsequent costs—of getting caught. We show that leverage levels and increases positively and significantly affect upward RM, with no significant effect on income-increasing AM, while our findings point towards a complementarity effect between unexpected levels of RM and AM for firms with very high leverage levels and changes. This is interpreted as an indication that high leverage could attract heavy outsider scrutiny, making it necessary for firms to use both forms of earnings management in order to achieve earnings targets. Furthermore, we document that equity investors exhibit a significantly stronger penalising reaction to AM vs. RM, indicating that leverage-induced RM is not as easily detectable by market participants as debt-induced AM, despite the fact that the former could imply deviation from optimal business practices
A new morphometric method for the sella turcica and the hypophyseal fossa and its clinical relevance
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
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
Recommended from our members
The option market reaction to bank loan announcements
In this study, we examine the options market reaction to bank loan announcements for the population of US firms with traded options and loan announcements during 1996-2010. We get evidence on a significant options market reaction to bank loan announcements in terms of levels and changes in short-term implied volatility and its term structure, and observe significant decreases in short-term implied volatility, and significant increases in the slope of its term structure as a result of loan announcements. Our findings appear to be more pronounced for firms with more information asymmetry, lower credit ratings and loans with longer maturities and higher spreads. Evidence is consistent with loan announcements providing reassurance for investors in the short-term, however, over longer time horizons, the increase in the TSIV slope indicates that investors become increasingly unsure over the potential risks of loan repayment or uses of the proceeds
The Examination of Injuries in Dancers
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
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
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
- …