Body frontal area in passerine birds

Projected body frontal area is used when estimating the parasite drag of bird flight. We investigated the relationship between projected frontal area and body mass among passerine birds, and compared it with an equation based on waterfowl and raptors, which is used as default procedure in a widespread software package for flight performance calculations. The allometric equation based on waterfowl/raptors underestimates the frontal area compared to the passerine equation presented here. Consequently, revising the actual frontal areas of small birds will concomitantly change the values of the parasite drag coefficient. We suggest that the new equation S-b = 0.0129m(B)(0.61) (m(2)) where m(B) is body mass (kg) should be used when a value of frontal area is needed for passerines

Gliding flight in a jackdaw: a wind tunnel study

We examined the gliding flight performance of a jackdaw Corvus monedula in a wind tunnel. The jackdaw was able to glide steadily at speeds between 6 and 11 m s(-1). The bird changed its wingspan and wing area over this speed range, and we measured the so-called glide super-polar, which is the envelope of fixed-wing glide polars over a range of forward speeds and sinking speeds. The glide super-polar was an inverted U-shape with a minimum sinking speed (V(ms)) at 7.4 m s(-1) and a speed for best glide (V(bg)) at 8.3 m s(-)). At the minimum sinking speed, the associated vertical sinking speed was 0.62 m s(-1). The relationship between the ratio of lift to drag (L:D) and airspeed showed an inverted U-shape with a maximum of 12.6 at 8.5 m s(-1). Wingspan decreased linearly with speed over the whole speed range investigated. The tail was spread extensively at low and moderate speeds; at speeds between 6 and 9 m s(-1), the tail area decreased linearly with speed, and at speeds above 9 m s(-1) the tail was fully furled. Reynolds number calculated with the mean chord as the reference length ranged from 38 000 to 76 000 over the speed range 6-11 m s(-1). Comparisons of the jackdaw flight performance were made with existing theory of gliding flight. We also re-analysed data on span ratios with respect to speed in two other bird species previously studied in wind tunnels. These data indicate that an equation for calculating the span ratio, which minimises the sum of induced and profile drag, does not predict the actual span ratios observed in these birds. We derive an alternative equation on the basis of the observed span ratios for calculating wingspan and wing area with respect to forward speed in gliding birds from information about body mass, maximum wingspan, maximum wing area and maximum coefficient of lift. These alternative equations can be used in combination with any model of gliding flight where wing area and wingspan are considered to calculate sinking rate with respect to forward speed

Optimizing NUCA organizations and wiring alternatives for large caches with CACTI 6.0

Journal ArticleA significant part of future microprocessor real estate will be dedicated to L2 or L3 caches. These on-chip caches will heavily impact processor performance, power dissipation, and thermal management strategies. There are a number of interconnect design considerations that influence power/performance/area characteristics of large caches, such as wire models (width/spacing/repeaters), signaling strategy (RC/differential/transmission), router design, etc. Yet, to date, there exists no analytical tool that takes all of these parameters into account to carry out a design space exploration for large caches and estimate an optimal organization. In this work, we implement two major extensions to the CACTI cache modeling tool that focus on interconnect design for a large cache. First, we add the ability to model different types of wires, such as RC-based wires with different power/delay characteristics and differential low-swing buses. Second, we add the ability to model Non-uniform Cache Access (NUCA). We not only adopt state-of-the-art design space exploration strategies for NUCA, we also enhance this exploration by considering on-chip network contention and a wider spectrum of wiring and routing choices. We present a validation analysis of the new tool (to be released as CACTI 6.0) and present a case study to showcase how the tool can improve architecture research methodologies

Flight Speeds among Bird Species: Allometric and Phylogenetic Effects

Flight speed is expected to increase with mass and wing loading among flying animals and aircraft for fundamental aerodynamic reasons. Assuming geometrical and dynamical similarity, cruising flight speed is predicted to vary as (body mass)1/6 and (wing loading)1/2 among bird species. To test these scaling rules and the general importance of mass and wing loading for bird flight speeds, we used tracking radar to measure flapping flight speeds of individuals or flocks of migrating birds visually identified to species as well as their altitude and winds at the altitudes where the birds were flying. Equivalent airspeeds (airspeeds corrected to sea level air density, Ue) of 138 species, ranging 0.01–10 kg in mass, were analysed in relation to biometry and phylogeny. Scaling exponents in relation to mass and wing loading were significantly smaller than predicted (about 0.12 and 0.32, respectively, with similar results for analyses based on species and independent phylogenetic contrasts). These low scaling exponents may be the result of evolutionary restrictions on bird flight-speed range, counteracting too slow flight speeds among species with low wing loading and too fast speeds among species with high wing loading. This compression of speed range is partly attained through geometric differences, with aspect ratio showing a positive relationship with body mass and wing loading, but additional factors are required to fully explain the small scaling exponent of Ue in relation to wing loading. Furthermore, mass and wing loading accounted for only a limited proportion of the variation in Ue. Phylogeny was a powerful factor, in combination with wing loading, to account for the variation in Ue. These results demonstrate that functional flight adaptations and constraints associated with different evolutionary lineages have an important influence on cruising flapping flight speed that goes beyond the general aerodynamic scaling effects of mass and wing loading

Protein tau concentration in blood increases after SCUBA diving: an observational study

PURPOSE: It is speculated that diving might be harmful to the nervous system. The aim of this study was to determine if established markers of neuronal injury were increased in the blood after diving. METHODS: Thirty-two divers performed two identical dives, 48 h apart, in a water-filled hyperbaric chamber pressurized to an equivalent of 42 m of sea water for 10 min. After one of the two dives, normobaric oxygen was breathed for 30 min, with air breathed after the other. Blood samples were obtained before and at 30-45 and 120 min after diving. Concentrations of glial fibrillary acidic, neurofilament light, and tau proteins were measured using single molecule array technology. Doppler ultrasound was used to detect venous gas emboli. RESULTS: Tau was significantly increased at 30-45 min after the second dive (p < 0.0098) and at 120 min after both dives (p < 0.0008/p < 0.0041). Comparison of matching samples showed that oxygen breathing after diving did not influence tau results. There was no correlation between tau concentrations and the presence of venous gas emboli. Glial fibrillary acidic protein was decreased 30-45 min after the first dive but at no other point. Neurofilament light concentrations did not change. CONCLUSIONS: Tau seems to be a promising marker of dive-related neuronal stress, which is independent of the presence of venous gas emboli. Future studies could validate these results and determine if there is a quantitative relationship between dive exposure and change in tau blood concentration

Радиолокационное сечение рассеяния летательных аппаратов

Тез. докл. Междунар. науч.-техн. конф. (науч. чтения, посвящ. П. О. Сухому), Гомель, 4-6 июля. 2002 г

Birds in the Flow: Flight Mechanics, Wake Dynamics and Flight Performance

I share my fascination of bird flight with many others, and here I summarise my thesis on the subject. This thesis emphasises the mechanics of bird flight by focusing on flight mechanics, wake dynamics and flight performance. Gliding flight performance of a jackdaw was measured in a wind tunnel and I conclude that the current model for predicting optimum wingspan as a function of forward gliding speed is inadequate. As an alternative model I present a new set of equations. Two papers on the barn swallow concern changes in wingbeat kinematics and tail posture with flight speed. The tail is used extensively at low flight speeds, but the current approach to consider the tail a delta wing does not match the observed changes in tail posture and orientation. An analysis of head-on photographs of songbirds revealed that passerines have a larger projected body frontal area in relation to body mass than waterfowl and raptors, a result affecting the associated body drag coefficient. We have developed a novel method for making quantitative and qualitative measurements of the wake behind a bird flying in the wind tunnel. For the first time we can visualise the wake behind a bird, a thrush nightingale, over it's entire natural range of flight speeds. As part of the same series of measurements we studied the wingbeat kinematics under similar conditions. The main conclusions are: (i) The wake is complex and cannot be categorized as either of the two previously described types (closed vortex loops and undulating wingtip vortices of constant circulation). The wake is mostly of an intermediate type but at the extreme low speed and high speed, respectively, approximations to the closed loop and constant circulation models can be made. (ii) Enough vorticity to support the bird's weight was found, hence resolving the long-standing wake momentum paradox. (iii) The concept of discrete ‘gaits’ must be refuted for bird flight because the measured wake properties change continuously. (iv) A simple model to predict the wake topology for the entire range of flight speeds is suggested. (v) Wingbeat kinematics and wake topology have common denominators. To describe the hunting behaviour and flight performance of an aerial predator we tracked Eleonora’s falcons in free flight off the coast at a breeding colony on a small island in Italy. The Eleonora's falcon shows impressive flight performance and proves to be well adapted for hunting birds on the wing. On the basis of aerodynamic theory and the morphological adaptations of the prey and predator, we analysed theoretically the outcome of three different attack-escape situations

Soaring flight in the Eleonora's Falcon (Falco eleonorae)

Eleonora's Falcon (Falco eleonorae) breeds in the Mediterranean region and is highly adapted for catching small birds on passage migration between Eurasia and their African winter quarters, which they feed their young. We studied gliding flight behavior of Eleonora's Falcon at a breeding colony located on a small island southwest of Sardinia, Italy. Gliding and soaring flight performance was measured using an optical range finder and evaluated against flight mechanical theory. The male falcon does the majority of hunting and usually sets off from the colony to hunting areas located at high altitude over the open sea to catch prey. To lower the cost of transport and maximize the energy gain from hunting, we show that the birds use vertical winds for soaring when available. The occurrence of rising air changes with wind direction. At north-northwesterly winds (on-shore), slope lift is available outside the nesting cliffs, and at south-southeasterly winds thermals that form over the island drift out over the sea. Our observations demonstrated the flexibility of flight behavior in relation to the wind situation, and birds thereby make full use of available soaring conditions

Hur arbetar idrottslärare med elever i behov av särskilt stöd?

Syftet med studien är att genom en systematisk litteraturstudie studera varierande tillvägagångssätt för att inkludera elever med en funktionsnedsättning i undervisningen i idrott och hälsa. Studien kommer även belysa hur läraren kan anpassa lektionerna för alla elever med eller utan funktionsnedsättning. Slutsatsen är att det är viktigt att lärare lär känna sina elever för att kunna ha en bättre förståelse för elevens behov. Att bemästra en bra kontakt med elever, föräldrar och kuratorer är en bra utgångspunkt för att skapa givande lektioner för dessa elever. På så vis kan läraren planera undervisningen på bästa möjliga sätt. I resultatet framkommer även att elever med en funktionsnedsättning uppskattar idrotten och att idrottslektionerna bidrar till elevernas fysiska och mentala utveckling. Studien kommer även specifikt belysa funktionsnedsättningen autism HOH (hörselskadade) och elever med koncentrationssvårigheter. Studien belyser hur lärare ska inkludera eleverna med hjälp av olika strategier och metoder. Vad som är viktigt för läraren när det berör gester, ansiktsuttryck och tonläge framkommer således i resultatet. Slutligen visar resultatet att även om lärare är medvetna vad de kan göra för att främja dessa elever, finns det fortfarande hinder. Det finns inte alltid tillräckligt med anpassat material till elever med funktionsnedsättning som exempelvis sitter i rullstol. Det kan vara svårt att tillfredsställa alla elever i en klass med varierande aspekter att ta hänsynt till.