Evaluating Application-Layer Traffic Optimization Cost Metrics for P2P Multimedia Streaming

To help users of P2P communication systems perform better-than-random selection of communication peers, Internet Engineering Task Force standardized the"br/"Application Layer Traffic Optimization (ALTO) protocol. The ALTO provided data-routing cost metric, can be used to rank peers in P2P communication systems. However, the method to derive the data-routing cost metric is undefined by the standard. This paper proposes and evaluates three methods to derive the data-routing cost metric for use in ALTO servers

Optical detection of gadolinium(iii) ions quantum dot aggregation

A rapid, sensitive and selective optical readout of the presence of gadolinium(iii) ions would have a wide range of applications for clinical and environmental monitoring. We demonstrate that water-soluble CdTe quantum dots (QDs) are induced to aggregate by Gd3+ ions in aqueous solution. By using a combination of photoluminescence spectroscopy, dynamic light scattering and fluorescence correlation spectroscopy (FCS) to monitor quantum dot aggregation kinetics, we correlate the efficiency of the self-quenching process with the degree of aggregation across a broad range of conditions, including different sizes of QDs. We attribute the aggregation to metal binding to the QD's surface ligands and the quenching to intra-aggregate energy transfer between QDs. When the strategy was applied to additional trivalent ions, the aggregation rate varied according to the particular trivalent metal ion used, suggesting that the selectivity can be enhanced and controlled by appropriate design of the capping ligands and solution conditions

Utjecaj bavljenja sportskim igrama i cikličkim sportovima na mišićnu snagu i određene pokazatelje funkcije srčanožilnog sustava u dječaka dobi od 11 do 14 godina – longitudinalno istraživanje

The aim of the study was to determine the impact of sport games and cyclic sports on certain features of cardiovascular reactions to exercise and to muscular strength enhancement in a cohort of 105 boys at the age of 11–14 years. They were recruited at the age of eleven years: 35 non-athletes, 35 cyclic sports athletes and 35 sport games players. The measurements were performed for four consecutive years. The muscle strength and cardiovascular indices were registered and taken for analysis. The results indicate sport games training sessions are an important external factor affecting the functional parameters of accelerated changes in the cardiovascular system (CVS) of the 11–13-years-old age group. The influence of endogenous factors on a child’s growth and development particularly increases at the age of 13–14 years, resulting in significant changes in CVS indices improvement, and non-athletes almost equal peers engaged in sports for those characteristics. Improvement of the muscle capacity indices depends on the nature of the physical load: muscle strength indices increased more in the cyclic sports group.Cilj istraživanja bio je utvrditi utjecaj bavljenja sportskim igrama i cikličkim sportovima na određene karakteristike srčanožilne reakcije/adaptacije na tjelesno vježbanje i na povećanje mišićne snage na uzorku od 105 dječaka u dobi od 11 do 14 godina. Dječaci su bili uključeni u istraživanje u dobi od 11 godina: 35 ne-sportaša, 35 sportaša koji se bave cikličkim sportovima te 35 sportaša iz sportskih igara. Mjerenja su provedena tijekom četiri uzastopne godine. Zabilježeni su i analizirani pokazatelji mišićne snage i parametri funkcije srčanožilnog sustava. Rezultati pokazuju da su treninzi sportskih igara važan vanjski čimbenik koji utječe na funkcionalne parametre ubrzanih promjena srčanožilnog sustava u dječaka dobi 11–13 godina. Utjecaj endogenih faktora na rast i razvoj djeteta posebno se povećava u dobi 13–14 godina te rezultira značajnim promjenama u smjeru poboljšanja karakteristika funkcije srčanožilnog sustava, tolikima da su se ne-sportaši u tim karakteristikama gotovo izjednačili sa svojim vršnjacima uključenima u sportske aktivnosti. Poboljšanje pokazatelja mišićnih kapaciteta ovisi o karakteristikama fizičkog opterećenja: pokazatelji mišićne snage više su se povećali u sportaša koji su se bavili cikličkim sportovima

Mišicna izvedba, promjene središnjih i perifernih kardiovaskularnih parametara tijekom inkrementalne bicikl ergometrije

Mišicna aktivnost je cimbenik koji najbrže i u najvecoj mjeri može promijeniti aktivnost kardiovaskularnog sustava. Promjene kardiovaskularnih funkcija mijenjaju se u skladu s promjenom fizickog opterecenja do maksimuma. Cilj ovog istraživanja bio je utvrditi razlike u dinamici središnjih i perifernih kardiovaskularnih parametara ovisno o funkcionalnoj pripremljenosti tijekom inkrementalne bicikl ergometrije. Svi ispitanici podvrgnuti su racunalnom stres testu vježbe na biciklu. Sudionici su podijeljeni u dvije podskupine: više i niže tjelesne izvedbe: ispitanici u podskupini A, koji su u mogucnosti obavljati opterecenje od 250W i više (pod-skupina A visoke tjelesne izvedbe); i ispitanici podskupine B, koji su bili u mogucnosti izvršiti opterecenje manje od 250 W (podskupina B niže tjelesne izvedbe). Korištena je racunalna EKG analiza sustava "Kaunas opterecenja" za stalno 12 - kanalno EKG snimanje i analize. Analizirana je frekvencija srca (HR). Neizravna mjerenja arterijskog krvnog tlaka (ABP) napravljena su na ruci sa sfigmomanometarom i manžetom standardne velicine na ruci prije, na kraju svake minute tijekom opterecenja i tijekom oporavka. Zasicenja kisikom (StO2) i protok krvi u mišicima (m. vastus lateralis) zabilježeni su bliskom infracrvenom spektroskopijom (NIRS). Tijekom postupnog inkrementalnog opterecenja do otkaza, razlike u funkcionalnoj pripremljenosti mogu se vidjeti samo tijekom pocetne faze vježbanja (doziranog opterecenja), ali kada opterecenje postaje subjektivno teško, odnosno u posljednjoj fazi ispitivanja (maksimalno opterecenje), razlike izmedu središnjih kardiovaskularnih funkcionalnih parametara nisu pronadene, dok su razlike izmedu perifernih kardiovaskularnih funkcionalnih parametara bile vidljive blizu maksimalnog opterecenja: povecanje opterecenja smanjilo je zasicenost kisikom i protok krvi u aktivnim mišicima

Effect of Lower Body Compression Garments on Hemodynamics in Response to Running Session

Purpose. Compression garments are often worn during exercise and allegedly have ergogenic and/or physiological effects. In this study, we compared hemodynamics and running performance while wearing compression and loose-fit breeches. We hypothesized that in neutral-warm environment compression breeches impair performance by diminishing body cooling via evaporative sweat loss and redistributing blood from active musculature to skin leading to a larger rise in body temperature and prolonging recovery of hemodynamics after exercise. Methods. Changes in hemodynamics (leg blood flow, heart rate, and blood pressure during orthoclinostatic test), calf muscle tissue oxygenation, and skin and core temperatures were measured in response to 30 min running (simulation of aerobic training session) followed by maximal 400 m sprint (evaluation of running performance) in recreationally active females (25.1±4.2 yrs; 63.0±8.6 kg) wearing compression or loose-fit breeches in randomized fashion. Results. Wearing compression breeches resulted in larger skin temperature rise under the garment during exercise and recovery (by about 1°C, P<0.05; statistical power > 85%), while core temperature dynamics and other measured parameters including circulation, running performance, and sensations were similar compared to wearing loose-fit breeches (P>0.05). Conclusion. Compared with loose-fit breeches, compression breeches have neither positive nor negative physiological and performance effects for females running in thermoneutral environment