Wing Extensions Research Articles

3D reconstruction of bird flight trajectories using a single video camera.

Video cameras are finding increasing use in the study and analysis of bird flight over short ranges. However, reconstruction of flight trajectories in three dimensions typically requires the use of multiple cameras and elaborate calibration procedures. We present an alternative approach that uses a single video camera and a simple calibration procedure for the reconstruction of such trajectories. The technique combines prior knowledge of the wingspan of the bird with a camera calibration procedure that needs to be used only once in the lifetime of the system. The system delivers the exact 3D coordinates of the position of the bird at the time of every full wing extension and uses interpolated height estimates to compute the 3D positions of the bird in the video frames between successive wing extensions. The system is inexpensive, compact and portable, and can be easily deployed in the laboratory as well as the field.

Drosophila functional screening of de novo variants in autism uncovers damaging variants and facilitates discovery of rare neurodevelopmental diseases.

SUMMARYIndividuals with autism spectrum disorder (ASD) exhibit an increased burden of de novo mutations (DNMs) in a broadening range of genes. While these studies have implicated hundreds of genes in ASD pathogenesis, which DNMs cause functional consequences in vivo remains unclear. We functionally test the effects of ASD missense DNMs using Drosophila through “humanization” rescue and overexpression-based strategies. We examine 79 ASD variants in 74 genes identified in the Simons Simplex Collection and find 38% of them to cause functional alterations. Moreover, we identify GLRA2 as the cause of a spectrum of neurodevelopmental phenotypes beyond ASD in 13 previously undiagnosed subjects. Functional characterization of variants in ASD candidate genes points to conserved neurobiological mechanisms and facilitates gene discovery for rare neurodevelopmental diseases.

Sphenoid sinus pneumatization in a sample of Nepalese population: A multidetector computed tomography study.


 Introduction: The purpose of study was to assess the prevalence of different types of pneumatization of sphenoid sinus in the Nepalese population as detected in CT scan of paranasal sinus. Materials and Methods: This study included patients attending radiology department for CT scan of paranasal sinus. The CT images of paranasal sinus were assessed for the type of pneumatization of the sphenoid sinus and type of clival, lateral recess and lesser wing extensions. Results: Most common type of pneumatization found in our study was complete sellar type (61.7%) and partial sellar type was second common type (27.4%). Pre-sellar type of pneumatization was seen in 10.9%. There were no patients with conchal type of pneumatization in our study. The clival extension of pneumatization was seen in 64%, lateral extension was found in 35.4%. and lesser wing type of pneumatization was found in 9.7%. Conclusion: Pre-surgical assessment of types and extension of sphenoid sinus pneumatization helps surgeons in surgical planning and to reduce complications during surgery. The variation in prevalence of sphenoid sinus pneumatization was found between our study population and other different population. This confirms that ethnicity influences types and extension of sphenoid sinus pneumatization.

Assessment of variations in sphenoid sinus pneumatization in Indian population: A multidetector computed tomography study.

Background and Purpose:The purpose of our study was to assess the prevalence of variations in the extent of sphenoid pneumatization in the Indian population and compare with existing literature.Materials and Methods:This retrospective study included 500 patients who underwent CT of the paranasal sinuses. The multiplanar reformations of paranasal sinus were assessed for the type of pneumatization of the sphenoid sinus and type of clival, lateral recess, lesser wing, and anterior recess extensions.Results:The conchal, presellar, incomplete sellar, and complete sellar types comprised 0%, 1.2%, 22.2%, and 76.6% of patients. The extensions of pneumatization subtypes in the study population were clival in 76.6% subjects; lateral recess, lesser wing, and anterior recess in 59.7%, 20.4%, and 20.4% of sinuses, respectively. The pure forms were seen in 25.4% and combined forms in 61% of sinuses. The presellar type (1.2%) was less common and sellar type (98.8%) being common in our population compared to the Caucasian and East Asian population. The sphenoid sinuses were extensively pneumatized in our population compared to the Chinese and Caucasian population, the prevalence being 76.6%, 68%, and 44.5% for clival; 59.7%, 46%, and 28.3% for lateral recess; 20.4%, 32%, and 12% for lesser wing extension, respectively. The pure forms were relatively less common and combined forms being more common compared to the Chinese and Caucasian population in our study.Conclusion:The extent of pneumatization of the sphenoid sinus has clinical and surgical implications in sellar and central skull base lesions, and variability in different populations confirms that ethnicity influences the differences in prevalence.

Aeroelastic Optimization of High-Speed Tiltrotor Wings with Wing Extensions and Winglets

Tiltrotors can experience an aeroelastic instability called whirl flutter, which is characterized by highly coupled wing–rotor vibrations, which are catastrophic in nature and limit the maximum speed of the aircraft. In this paper, an optimization study aimed at improving the whirl flutter speed of a tiltrotor equipped with a wing extension and a winglet is presented. Parametric studies are conducted on an aeroelastic model of a rotor mounted on a cantilevered wing with an extension and a winglet. The parameters that are investigated are stiffness, structural taper, composite couplings, extension sweep, and winglet cant angle. It is found that, when the wing has a structural taper and is equipped with a wing extension and a winglet, the whirl flutter speed can be increased by 15%. The parametric study is followed by an optimization study to determine the optimal combinations of these parameters that maximize whirl flutter speed. Genetic algorithms are used for the optimization process. Upper and lower bounds are placed as constraints on the design variables. It is shown that the optimized design has a flutter speed of 22% (65 kt) more than the baseline.

채널 내를 비행하는 가변스팬 날개 공력특성 II (비대칭 날개 펼침)

채널 내를 비행하는 가변스팬 날개 공력특성 II (비대칭 날개 펼침)

Experimental Study on the Effects of Winglets on the Performance of Two Interacting Horizontal Axis Model Wind Turbines

The focus of this experimental study is to investigate the effects of winglets on the performance of two interacting similar horizontal axis model wind turbines. For this purpose, a downwind winglet is designed and manufactured to be attached to the blade tips of the upstream turbine. A set of wing extensions with the same length as the winglets is also produced to be compared to the winglets. Power and thrust coefficients of both turbines are measured with winglets as well as with wing extensions attached to the blade tips of the upstream turbine and are compared to the baseline case (rectangular tip without any tip devices). The model turbines are three bladed and have a rotor diameter of 0.94 m. The measurements are performed in two different wind tunnels (closed test section and open jet). For both sets of measurements, winglets have a noticeable increasing effect on the power coefficient of the individual turbine. There is an increase in the thrust coefficient as well. Measurements on the second turbine are done while it is positioned at downstream locations in line with the upstream turbine. Results show that it produces less power while operating in the wake of the upstream turbine with winglets. However, the overall power efficiency of two turbines can increase for the wingletted case. Moreover, results with wing extensions show that although upstream turbine produces more power with wing extensions attached, the power coefficient remains the same as the baseline case due to growth in rotor swept area and hence, it is less than the power coefficient of wingletted turbine.

Neuronal Control of Drosophila Courtship Song

The courtship song of the Drosophila male serves as a genetically tractable model for the investigation of the neural mechanisms of decision-making, action selection, and motor pattern generation. Singing has been causally linked to the activity of the set of neurons that express the sex-specific fru transcripts, but the specific neurons involved have not been identified. Here we identify five distinct classes of fru neuron that trigger or compose the song. Our data suggest that P1 and pIP10 neurons in the brain mediate the decision to sing, and to act upon this decision, while the thoracic neurons dPR1, vPR6, and vMS11 are components of a central pattern generator that times and shapes the song's pulses. These neurons are potentially connected in a functional circuit, with the descending pIP10 neuron linking the brain and thoracic song centers. Sexual dimorphisms in each of these neurons may explain why only males sing.

Genetic Feminization of the Thoracic Nervous System Disrupts Courtship Song in Male Drosophila melanogaster

: Despite the growing research investigating the sex-specific organization of courtship behavior in Drosophila melanogaster, much remains to be understood about the sex-specific organization of the motor circuit that drives this behavior. To investigate the sex-specification of a tightly patterned component of courtship behavior, courtship song, the authors used the GAL4/UAS targeted gene expression system to feminize the ventral ganglia in male Drosophila and analyzed the acoustic properties of courtship song. More specifically, the authors used the thoracic-specifying teashirt promoter (tshGAL4) to express feminizing transgenes specifically in the ventral ganglia. When tshGAL4 drove expression of transformer (tra), males were unable to produce prolonged wing extensions. Transgenic expression of an RNAi construct directed against male-specific fruitless (fruM) transcripts resulted in normal wing extension, but highly defective courtship song, with 58% of males failing to generate detectable courtship song. Of those that did sing, widths of individual pulses were significantly broader than controls, suggesting thoracic fruM function serves to mediate proprioceptive-dependent wing vibration damping during pulse song. However, the most critical signal in the song, the interpulse interval, remained intact. The inability to phenocopy this effect by reducing fruM expression in motor neurons and proprioceptive neurons suggests thoracic interneurons require fruM for proper pulse song execution and patterning of pulse structure, but not for pulse timing. This provides evidence that genes establishing sex-specific activation of complex behaviors may also be used in establishing pattern-generating motor networks underlying these sex-specific behaviors.

Calculation of the broadening of HeI 10830Å for a solar limb flare

In this paper the Doppler and Stark broadening mechanisms of HeI 10830Å are discussed and various broadening parameters calculated. The following conclusions are drawn: compared to the Doppler effect, the action of radiative damping on the broadening of HeI 10830Å can be neglected. For the generally acknowledged value of electron density of flares ( N e = 3.2 x 10 13cm −3), none of the damping terms can produce any discernible broadening. Up to N e = 10 15cm −3, none of the various types of damping can effect an increase in the half-width of the line center, and the maximum increase is of the order of 10 −3Å. Therefore, the broadening at the line center may always be thought to be Doppler broadening. When N e > 10 14 cm −3, Stark broadening, especially the Stark broadening of electrons, plays the chief role in the broadening of HeI 10830Å. If the wings of the Stark-broadened profile are to be 2–3 times larger than those of the purely Doppler-broadened profile, then the half-width of damping broadening should be comparable to Δλ D . If the observed profile of the limb flare of 1989 is interpreted as Stark broadening, then the electron density would be as high as 10 17 cm −3. The collisional damping (γ 3) with helium atoms causes clearly different amounts of broadening on the components I 12 and I 3: the effect is one order of magnitude higher on I 12 than on I 3. But our observation shows that the wing extensions of I 12 and I 3 are basically the same, so it is impossible that our observed profile is produced by γ 3.

Extended reproductive roles of the fruitless gene in Drosophila melanogaster revealed by behavioral analysis of new fru mutants.

The fruitless mutants fru3 and fru4 were assessed for sex-specific reproductive-behavioral phenotypes and compared to the previously reported fru mutants. Among the several behavioral anomalies exhibited by males expressing these relatively new mutations, some are unique. fru3 and fru4 males are less stimulated to court females than fru1 and fru2. No courtship pulse song is generated by either fru3 or fru4 males, even though they perform brief wing extensions. fru3 and fru4 males display significantly less chaining behavior than do fru1 males. The hierarchy of courtship responses by fru males directed toward females vs. males, when presented with both sexes simultaneously, is that fru1 males perform vigorous and indiscriminant courtship directed at either sex; fru4 males are similarly indiscriminant, but courtship levels were lower than fru1; fru2 males prefer females; fru3 males show a courtship bias toward males. fru3 and fru4 males essentially lack the Muscle of Lawrence (MOL). On several reproductive criteria, there was no difference between fru-variant females and fru+. The increases in phenotypic severity measured for the new mutants are discussed in the context of the emerging molecular genetics of fru and with regard to the gene's position within the sex-determination pathway.

Courtship Display and Mating of Victoria's Riflebird Ptiloris victoriae with Notes on the Courtship Displays of Congeneric Species

The courtship display and mating of Victoria's Riflebird Ptiloris victoriae are described from numerous hours of direct observations and 117 minutes of videotape. Courtship display is typically performed on the apex of a vertical dead tree trunk stump and consists of three discrete components: Calling with the associated exposure of a bright mouth, a Circular wings and gape display and a vigorous Alternate wing clap display that all but embraces the female with rapidly alternating wing extensions and synchronous jerking of the stiffly rigid head and neck between them at a progressively rapid tempo until copulation. Subjective observations indicate that in immature, female- and sub-adult male-plumaged males the advertisement call is inferior in power and the courtship displays lacking in synchronisation and coordination of postures and movements. Victoria's Riflebird courtship is compared with that of congeneric riflebirds and with other sexually dimorphic polygynous birds of paradise and similarities discussed. Contrary to previous views, the courtship display of Victoria's Riflebird involves a progressive series of specific postures and movements increasing in tempo and leading to copulation. Some of its courtship behaviour is similar to that of other genera in the Paradisaeinae.

Mechanics of the avian propatagium: Flexion-extension mechanism of the avian wing.

The supporting elements of the avian propatagium were examined in intact birds and as isolated components, using static force-length measurements, calculated models, and airflow observations. The propatagial surface supported between Lig. propatagiale (LP) and brachium-antebrachium is equally resistant to distortion over the range of wing extension used in flight. The lengths LP assumes in flight occur across a nearly linear, low-stiffness portion of the force-length curve of its extensible pars elastica. In an artificial airflow, intact wings automatically extend; their degree of extension is roughly correlated with the airflow velocity. Comparisons between geometric models of the wing and the passive force-length properties of LPs suggest that the stress along LP blances the drag forces acting to extend the elbow. The mechanical properties (stiffness) of the LP vary and appear to be tuned for flight-type characteristics, e.g., changes in wing extension during flight and drag. Lig. limitants cubiti and LP combine to limit elbow extension at its maximum, a safety device in flight preventing hyperextension of the elbow and reduction of the propatagium's cambered flight surface. Calculations using muscle and ligament lengths suggest that M. deltoideus, pars propatagialis, via its insertions onto both the propatagial ligaments, controls and coordinates propatagial deployment, leading edge tenseness, and elbow/wing extension across the range of wing extensions used in flight. The propatagial ligaments and M. deltoideus, pars propatagialis, along with skeleto-ligamentous elbow/carpus apparatus, are integral components of the wing's extension control mechanism. © 1995 Wiley-Liss, Inc.

Anatomy of the propatagium: The great horned owl (Bubo virginianus).

Skinfolds and feathers form the profile of the avian airfoil. The wing of birds has a nearly flat profile from shoulder to carpus, without the presence of the propatagium. The propatagium is the largest skinfold of the wing; it fills the angle formed by the partially flexed elbow, and with its feathers forms a rounded leading edge and dorsally cambered profile added to the cranial aspect of the wing. The propatagium is variably deployed, relative to elbow extension, in flight; support for its cambered shape is maintained by multilayered collagenous and elastic tissue networks suspended between leading edge and dorsal antebrachium. The leading edge ligament (Lig. propatagiale) courses from deltopectoral crest to carpus and, with its highly distensible center section, supports the leading edge of the propatagium across a range of wing extensions. The elbow extension limiting ligament (Lig. limitans cubiti) courses from deltopectoral crest to proximal antebrachium and limits maximum elbow extension. M. deltoideus, pars propatagialis inserts on the proximal end of the common origin of the propatagial ligaments and, by way of the insertions of the two ligaments, coordinates (1) automatic flexion / extension actions of the elbow and wrist, (2) propatagial deployment, and (3) tension along the length of Lig. propatagiale supporting the leading edge. © 1994 Wiley-Liss, Inc.