Wing Area Research Articles

Global stability analysis of elastic aircraft in edge-of-the-envelope flow

Shock buffet on wings is a phenomenon caused by strong shock-wave/boundary-layer interaction resulting first in self-sustained flow unsteadiness and eventually in a detrimental structural response called buffeting. While it is an important aspect of wing design and aircraft certification, particularly for modern transonic air transport, not all of the underlying multidisciplinary physics is thoroughly understood. Building upon a single-discipline shock-buffet stability study, this work now investigates the impact of an elastic structure in these extreme flow conditions. Specifically, a triglobal stability analysis of a fluid–structure coupled system is presented, utilising the implicitly restarted Arnoldi method with a sparse iterative Krylov solver and novel preconditioner. Asymmetry resulting from a static aeroelastic simulation based on a finite-element model of the underlying geometry in a wind tunnel modifies the global modes of the earlier fluid-only symmetric full-span analysis. A flutter stability analysis at wind-tunnel flow conditions below shock-buffet onset finds no instability in the structural degrees-of-freedom, whereas in shock-buffet flow with globally unstable fluid modes additional marginally unstable structural (and fluid) modes emerge. The developed stability tool for coupled analysis is instrumental in identifying those physically relevant and strongly coupled modes where a standard pk-type (p being eigenvalue and k reduced frequency) flutter analysis fails. With the complementary computation of adjoint eigenmodes, the core of the instability is pinpointed to a relatively small wing area which may help to effect the control and delay of this detrimental transonic unsteadiness. We contribute to the question on how the presence of the elastic wing structure impacts on the otherwise pure aerodynamic three-dimensional shock-buffet dynamics.

Simulation Study of Aircraft Active-Active Hydroelectric Hybrid Power Drive Unit

The Power Drive Unit (PDU) is the power source of the aircraft high-lift system (HLS), which converts hydraulic or electric energy into mechanical energy for output, and deflects the flap/slat through the transmission lines to increase the wing area to improve lift. Two sets of hydraulic motor subsystems working simultaneously are used in the Active-Active PDU of traditional aircraft to improve the reliability of the system. In this paper, an Active-Active Hydroelectric Hybrid Power Drive Unit (HPDU) is designed with a fixed-displacement hydraulic motor and a permanent magnet synchronous motor, the fundamental composition of the HPDU is introduced, the mathematical model of main components is analyzed, the HPDU is modeled based on AMESim, and the function and operation performance are investigated by simulation. The results show that the HPDU can realize the functional design requirements such as forward and reverse rotation and the performance design requirements such as withstanding sudden load within the rated load range during running.

How the monarch got its spots: Long-distance migration selects for larger white spots on monarch butterfly wings.

Elucidating the adaptations that promote flight in animals can aid the understanding of evolution and species divergence, and/or provide inspiration for aerospace engineering and the design of better aerial vehicles. The famed long-distance migration of monarch butterflies in North America still holds many questions and opportunities for inspiration. For example, there is little research on whether the monarch's primary wing colors themselves (black, orange, or white) have any aerodynamic or migration function. Dark colors on wings of other animals have recently been shown to aid flight by enhancing solar absorption, which reduces drag forces. However, too much black surface could be problematic for monarchs, which are exposed to increasing amounts of solar energy along their flightpath. This paper describes the results of two related investigations that attempt to elucidate the importance of wing color to the monarch migration. By measuring the color proportions of nearly 400 monarch wings collected at different stages of their journey, we found, surprisingly, that successful migrants tended to have less black on their wings (about 3% less), but also more white pigment (about 3% more); monarchs have a band of light-colored marginal wing spots. Second, image analysis of museum specimens revealed migratory monarchs had significantly larger white spots, proportional to the wing area, than most non-migratory, New World Danaid butterflies, which argues spot size has evolved along with migratory behavior. Combined, these findings strongly suggest that the long-distance migration itself selects for larger white spots every fall, so that only those individuals with large spots will survive to pass on their genes. Further experimental work is needed to elucidate how the spots aid the migration, but it is possible that they enhance aerodynamic efficiency; other work by the authors demonstrates how alternating white and black pigment on wings can reduce drag. These results will serve as a useful starting point for such endeavors, which should improve understanding of one of the world's most fascinating animal migrations, and also provide practical knowledge for the field of aerospace engineering.

Relationship between flight muscle dimorphism and wing morphometry in Triatoma infestans (Klug, 1834) (Hemiptera, Reduviidae, Triatominae)

Triatoma infestans, the primary vector of Chagas disease in southern South America, is reported as a dimorphic species for flight muscle development and presents a marked phenotypic plasticity in traits related to flight. In triatomines, studying the relationship between flight muscle development and wing variation is important, since it involves flight capacity and dispersion. Therefore, we examined the association between flight muscle dimorphism and morphological wing variation in T. infestans individuals. We hypothesized that if the underdeveloped flight muscle were associated with a decrease in wing developmental stability, canalization and morphological aspect of wings, and with a loss of wing modularity, then wing variation would be associated with flight muscle dimorphism. Wing size and shape were characterized using geometric morphometrics. Patterns of canalization, developmental instability, and modularity were inferred from fluctuating asymmetry analysis of wing shape. Morphological aspects of wings were estimated using maximum wing length and wing area. The results showed that there are differences in wing shape but not in wing size among groups. Canalization and developmental stability were positively associated in individuals with muscle development and negatively associated in individuals with underdeveloped flight muscles. The covariance structure of variation among individuals was different between groups but not for fluctuating asymmetry, both for females and males. Modularity hypothesis related to the wing subdivision into two parts, a stiff part and a membranous one, showed significant association for the variation among individuals and fluctuating asymmetry variation in females with flight muscles. Wing aspect showed that females with flight muscles exhibited more elongated and thinner wings than those without flight muscles. The results obtained in this study reveal an association between flight muscle development and forewing variation in T. infestans. Females with flight muscles have certain differential characteristics in their wings that would be related to an enhanced flight performance.

Structural Design and Analysis of Small Flapping Wing Aircraft Based on the Crank Slider Mechanism

In this project, the miniaturization of the aircraft was realized under the premise of strong maneuverability, high concealability, and driving a certain load, and the flight mode and structural characteristics of birds were imitated. A small bionic flapping wing aircraft was built. The flapping of the wing was realized by the crank slider mechanism, and the sizes of each part were calculated according to the bionics formula. The wingspan was 360.37 mm, the body width was 22 mm, the body length was 300 mm, the wing area was 0.05 m2, the flapping amplitude was 71°. ADAMS software was used to simulate the dynamics of the designed aircraft, and the variation of flapping amplitude and angular velocity during the movement of the aircraft was obtained, which verified the feasibility of the mechanism. The prototype aircraft was made for flight test, and the designed bionic flapping wing aircraft achieved the expected effect. It provides a theoretical basis and data support for the design and manufacture of small flapping wing aircraft.

Subtractive colour mixing with bile pigments creates the rich wing palette of Graphium weiskei butterflies.

The wings of the purple spotted swallowtail Graphium weiskei are marked by an unusual bright colour pattern. Spectrophotometry on G. weiskei wings demonstrated the presence of a pigment with an absorption spectrum (peak wavelength λmax=676 nm) similar to that of the bile pigment sarpedobilin in the wings of the congeneric Graphium sarpedon (λmax=672 nm). Sarpedobilin alone causes cyan-blue wing areas, but the green-coloured areas of G. sarpedon wings result from subtractive colour mixing with the carotenoid lutein. Reflectance spectra of the blue-coloured areas of G. weiskei wings indicate that sarpedobilin is mixed with the short-wavelength-absorbing papiliochrome II. An enigmatic pigment, tentatively called weiskeipigment (λmax=580 nm), enhances the saturation of the blue colour. Weiskeipigment causes a purple colour in areas where the sarpedobilin concentration is low. The wings of the related papilionid Papilio phorcas contain the bile pigment pharcobilin (λmax=604 nm), as well as another sarpedobilin (λmax=663 nm). The cyan to greenish wings of P. phorcas are due to phorcabilin and sarpedobilin mixed with papiliochrome II. A survey of known subspecies of G. weiskei as well as of congeneric Graphium species of the 'weiskei' group shows various degrees of subtractive colour mixing of bilins and short-wavelength absorbers (carotenoids and/or papiliochromes) in their wings. This study illuminates the underestimated role of bile pigments in butterfly wing colouration.

A Mission-Oriented Flight Path and Charging Mechanism for Internet of Drones.

In addition to traditional battery exchange services and stationary charging stations, researchers have proposed wireless charging technology, such as decentralized laser charging or drone-to-drone charging in flight, to provide power to drones with insufficient battery electricity. However, the charging methods presented in the literature will inevitably cause drones to wait in line for charging during peak hours and disrupt their scheduled trips when the number of drones grows rapidly in the future. To the best of our knowledge, there have been no integrated solutions for drone flight path and charging planning to alleviate charging congestion, taking into account the different mission characteristics of drones and the charging cost considerations of drone operators. Accordingly, this paper provides adaptive charging options to help drone operators to solve the above-mentioned problems. Drones on ordinary missions can use conventional battery swap services, wired charging stations, or electromagnetic wireless charging stations to recharge their batteries as usual, whereas drones on time-critical missions can choose drone-to-drone wireless charging or decentralized laser charging deployed along the fight paths to charge the batteries of drones in flight. Notably, since fixed-wing drones have larger wing areas to install solar panels, they can also use solar energy to charge during flight if the weather is clear. The simulation results exhibited that the proposed work reduced the power load of the power grid during peak hours, met the charging needs of each individual drone during flight, and cut down the charging costs of drone operators. As a result, an all-win situation for drone operators, drone customers, and power grid operators was achieved.

Ecomorphological variation of the penguin wing.

Penguins (Aves, Sphenisciformes) are pursuit divers that feed mainly on krill, fish, and squid. Although they are opportunistic feeders, some species are more generalists than others and many show dietary preferences towardkrill and other crustaceans or fish and squid. Their diving depth seems to follow a body size pattern and relates to the type of item that they prey on. Penguins dive with their wing; hence their wing musculature is responsible for the animal maneuverability and strength while diving. In the present study, ecological traits such as diving depths and prey composition are used to explore if morphology relates to foraging habits. A geometric morphometric approach is used to quantitatively address these morphological differences in the wing apparatus of all extant penguins and a fossil species taking into consideration allometric and phylogenetic factors. Results show that morphological differences among penguins with different diets are significant and strong; groups are well separated with the greatest differences found between piscivorous and crustacivorous penguins. Dive depth has a moderate covariation with morphology and a strong correspondence with wing area. Last, Madrynornis mirandus, an exceptionally well-preserved fossil from the Miocene of Patagonia, is found to be close to the piscivorous and generalist piscivorous species. It is proposed that swimming styles correlate with specific traits of the anatomy of wing and pectoral girdle skeleton and muscles.

Improving the Size of the Propellers of the Parrot Mini-Drone and an Impact Study on its Flight Controller System

Unmanned Aerial Vehicles (UAVs) are widely used in transportation, delivery, surveillance and surveillance applications. The development of stable, resilient, and accurate flight based on turbulence and turbulence will likely become a key feature in the development of unique flight control systems. In this research, we studied the control system of a small Parrot mini drone, the Mambo drone, which was designed using the MATLAB program, while we added turbulence to the drone by changing the weight of the original plane in the design, where we increased the weight and calculated the vertical projection area of the propellers of the plane several times until we got the best space for the propellers able to carry more extra weight. We imposed an increase in the drone's weight due to bad conditions that the plane experienced during its flight, such as snow or dust falling on it. In order to make the aircraft bear these weather conditions without falling and colliding, we calculated an appropriate increase in the area of the aircraft wing, and we actually applied it in the MATLAB-R2021a Simulink program, and we got good results using simulation as well as in real-time inside the laboratory, turbulence was added in the simulation program. The new design of the propellers demonstrated the aircraft's ability to carry an additional payload of approximately one-third of the aircraft's weight, as shown in the roads chapter. In future work, we propose to use this design on larger aircraft with fixed propellers and to study the effects of other weather conditions on UAVs, such as the effect of temperature, humidity, and others.

Research on Methods of Improving Fuel Efficiency

In recent years, the improvement of aircraft fuel efficiency has been one of the hot topics discussed by scientists. Especially in today's increasingly tense environment of fossil fuels, how to effectively improve the fuel efficiency of aircraft engines is an important scientific problem facing us. The improvement of aircraft fuel efficiency depends not only on high-performance engines, but also on the structural design of the aircraft itself. Therefore, if the aircraft structure can be optimized, it is bound to improve the fuel efficiency of the aircraft and make it have a better flight distance in actual flight. The purpose of this paper is to illustrate ways to reduce emissions while improving fuel efficiency. A small paper airplane experiment is introduced to study the influence of wing area on speed, time, lift, drag and lift drag ratio, so as to further explore the central theme of this paper, including the analysis of many physical models. It also includes many products and ideas that engineers are now designing.

Sexual size and shape dimorphism, and allometric scaling in the pupal and adult traits of Eristalis tenax.

The patterns and amount of variation in size, shape, and/or life history traits between females and males are fundamentally important to gain the comprehensive understanding of the evolution of phenotypic diversity. In addition, the covariation of phenotypic traits can significantly contribute to morphological diversification and sexual dimorphism (SD). Using linear and geometric morphometrics, 237 Eristalis tenax specimens sampled from five populations were, therefore, comparatively assessed for the variation in sexual size dimorphism (SSD), sexual shape dimorphism (SShD), and life history traits, as well as for trait covariation (ontogenetic and static allometry). Pupal body, adult wing, and body mass traits were analyzed. Female-biased SSD was observed for pupal length, width, and centroid size, adult wing centroid size, mass, wing loading, and wing area. Conversely, pupal length/width ratio, developmental time, and mass were not found to be sexually dimorphic. Next, wing SShD, but not pupal body SShD was revealed, while allometry was found to be an important "determinant of SD" at the adult stage, with only a minor impact at the pupal stage. By comparing the patterns of covariance (based on allometric slope and intercept) between respective body mass and morphometric traits of pupae and adults, greater variation in allometric slopes was found in adult traits, while static allometries of the two stages significantly differed, as well. Finally, the results indicate that changes in the allometric intercept could be an important source of intraspecific variation and SD in drone fly adults.

Numerical study of the aerodynamic characteristics of airfoil with high-lift devices

The subject matter of this article is the aerodynamic profile of the wing with high-lift devices in the aircraft transport category. When high-lift devices are released, the aerodynamic flow of the wing changes significantly, this changes the stress-strain state of the wing. This relates not only to an increase in lift force due to a change in the curvature of the wing and an increase of the wing area, but also due to a change of the position of the center of pressure relative to the chord of the wing. The goal is to study the influence of wing high-lift devices on the aerodynamic characteristics of the profile during take-off, cruise, and landing cases using numerical methods. The obtained data will be used to determine the loads on the wing in various flight cases. The task is to determine the aerodynamic coefficients of lift and drag forces, changing the position of the pressure center during flight cases: take-off, cruise, and landing. The aerodynamic profile b737c-il was used in the analysis. The single-slot slat and double-slots flap were used in the analysis model. The numerical methods with the CAE system ANSYS Fluent were used. The solver models k-epsilon and transition SST were used for comparison. The use of numerical methods in the process of designing aircraft structures is widely used to accurately determine the aerodynamic parameters of the wing in various flight cases. The following results were obtained: the dependence of the lift coefficient on the angle of attack, the lift coefficient on the drag coefficient, and the position of the center of pressure along the chord of the profile for cruise, take-off, and landing flight cases. Conclusion. The scientific novelty of the results obtained is as follows: the use of numerical methods for determining the aerodynamic characteristics of a wing with high-lift devices in particular, determining the dependence of the position of the center of pressure relative to the chord and at different angles of attack. The obtained results will be used to determine the load on the wing, in particular the distributed load on the slats and flaps, to clarify the torque moment in the wing section where high-lift devices are used.

Seasonal plasticity in morphology and metabolism differs between migratory North American and resident Costa Rican monarch butterflies.

Environmental heterogeneity in temperate latitudes is expected to maintain seasonally plastic life-history strategies that include the tuning of morphologies and metabolism that support overwintering. For species that have expanded their ranges into tropical latitudes, it is unclear the extent to which the capacity for plasticity will be maintained or will erode with disuse. The migratory generations of the North American (NA) monarch butterfly Danaus plexippus lead distinctly different lives from their summer generation NA parents and their tropical descendants living in Costa Rica (CR). NA migratory monarchs postpone reproduction, travel thousands of kilometers south to overwinter in Mexico, and subsist on little food for months. Whether recently dispersed populations of monarchs such as those in Costa Rica, which are no longer subject to selection imposed by migration, retain ancestral seasonal plasticity is unclear. To investigate the differences in seasonal plasticity, we reared the NA and CR monarchs in summer and autumn in Illinois, USA, and measured the seasonal reaction norms for aspects of morphology and metabolism related to flight. NA monarchs were seasonally plastic in forewing and thorax size, increasing wing area and thorax to body mass ratio in autumn. While CR monarchs increased thorax mass in autumn, they did not increase the area of the forewing. NA monarchs maintained similar resting and maximal flight metabolic rates across seasons. However, CR monarchs had elevated metabolic rates in autumn. Our findings suggest that the recent expansion of monarchs into habitats that support year-round breeding may be accompanied by (1) the loss of some aspects of morphological plasticity as well as (2) the underlying physiological mechanisms that maintain metabolic homeostasis in the face of temperature heterogeneity.

Wind variability limits the potential influence of propagule morphology and descent rate on dispersal in the winged fruits of Carpinus (Betulaceae)

The dispersal of propagules is an important aspect of land plant life history that has the potential to impact diverse evolutionary and ecological processes. Identifying the relationship between form and function of extant propagules provides the opportunity to infer past dispersal processes using morphological information from fossils, especially for abiotic dispersal of winged propagules. Many studies under laboratory conditions have identified wing loading (propagule mass divided by wing area) as the character most important for descent rates of winged propagules, but its influence on dispersal distances in natural environments over entire dispersal seasons remains unclear. To clarify this relationship, morphological measurements and experimental drops were performed on dispersed propagules from two species of Carpinus collected along highly resolved transects radiating from individual source trees. A significant relationship was found between wing loading and descent rate in still air, but the relationship between wing loading and actual dispersal distance in the field was random in all directions. Results indicate that variable wind conditions over a dispersal season can erase any signal of form and descent rate on dispersal patterns. Consequently, this randomization should impact evolutionary patterns by hampering selective potential for details of form that might further slow descent rates once enough of a wing evolves for propagules to exhibit a consistent specialized aerodynamic behavior.

Sensitivity Analysis of Wing Geometric and Kinematic Parameters for the Aerodynamic Performance of Hovering Flapping Wing

The wing planform and flapping kinematics are critical for the hovering flight of flapping wing micro air vehicles (FWMAVs). The degree of influence of wing geometry and kinematic parameters on aerodynamic performance still lacks in-depth analysis. In this study, a sensitivity analysis was conducted based on the quasi-steady aerodynamic model. Each parameter was investigated independently by using the control variable method. The degree of each variable’s influence on lift, power, and power loading is evaluated and compared. Furthermore, detailed exponential relationships were established between the parameters and the corresponding aerodynamic properties. It is found that, for the geometric parameters, wing area has the greatest influence on lift, and the distribution of area has the most visible effect on aerodynamic power. All geometric parameters are negatively correlated with power loading. For the kinematic parameters, flapping frequency, compared with sweeping amplitude, results in faster lift growth and slower drop in power loading, while their influence on aerodynamic power is nearly comparable. A moderate pitching amplitude with advanced rotation will maximize the lift. For the flapping trajectory, lift and power loading are primarily affected by the shape of the pitching motion rather than the sweeping motion. But the sweeping motion seems to dominate the power consumption. The research in this paper is helpful to understand the effect of each parameter and provide theoretical guidance for the development of FWMAVs.

Application of electrolaminates for the development of biomimetic morphing unmanned aerial vehicles

Morphing aircraft offer the promise of performance that can be optimized for a range of flight profiles. But such capability places challenging demands on the morphing system that cannot easily be met with conventional actuators or smart materials. Electrolaminates use electrostatic forces controlled by the application of a voltage (typically high-voltage but extremely low-current) to controllably bond or unbond layers of a laminated composite structure together. Such on-demand bonding can be used to effectively change the stiffness of the structure or control elongation or twist of the structure. This technology has multiple benefits compared to other smart material or conventional actuator-driven approaches; it is thin and light, has very low energy requirements, and offers rapid response capabilities controlled by simple electronics. These capabilities can enable bio-inspired morphing with large numbers of degrees of freedom and high spatial resolution. We designed, fabricated, and tested a fully functional morphing-wing unmanned aerial vehicle (UAV) with telescoping wings and a splaying, bird-like tail enabled by electrolaminates. Key features of the current UAV configuration include: a variable wingspan of 1.2–2.4 m with a corresponding change in the wing area of nearly a factor of four; no vertical tail; and a horizontal tail area variable by a factor of three. The ability to asymmetrically control the tail area allows for independent pitch and body circulation control. The tail area is changed by a separate electrolaminate clamping mechanism. The variable-area tail uses ‘feathers’ that can be overlapped or splayed as needed. The practical shape-changing is enabled by electrolaminate materials that can rapidly lock the orientation of the feathers. The electrolaminate clutches support more than 5 nm of torque and are sufficient to resist expected flight loads. We also designed, fabricated, and tested other morphing-wing designs enabled by electrolaminate technology to create a wing with smoothly sliding skin that is capable of changing chord and camber with a single linear actuator. Our results suggest that electrolaminates can practically enable bio-inspired, small (Group 1 and 2) morphing UAVs.

Entomoneis grisslehamnensis, a New Diatom (Bacillariophyceae) from the Baltic Coast of Sweden with taxonomic and ecological notes on Entomoneis paludosa (W. Smith) Reimer

The diatom genus Entomoneis includes species with panduriform frustules characterized by a bilobate, elevated keel, sigmoid raphe canal and numerous open, porous girdle bands. During a phytoplankton survey along the Baltic coast of Sweden, we observed numerous Entomoneis cells, some belonging to the well-known Entomoneis paludosa, while others remained unknown. Morphological and ultrastructural studies of the unknown species were performed with light microscopy (LM), scanning (SEM) and transmission (TEM) electron microscopy, and revealed a unique set of morphological characters. Live cells of Entomoneis grisslehamnensis sp. nov. contain one plate-like plastid and show various degrees of torsion about the apical axis. Microscopic features of cleaned frustules are discussed in comparison with similar species. Most importantly, every 2nd to 5th virga is strongly elevated, uniseriate striae are composed of quadrangular areolae with finely perforated hymenes; the winged keel with a discernible raphe canal is structurally strengthened by raphe fibulae with a flattened wing area, and the main part of the valve bulges towards the margins; striation is decussate on the wings and there is one row of raphe canal areolae at the central area. In addition to describing this new species of an underappreciated, yet cosmopolitan diatom genus, we contribute to the taxonomy of E. paludosa with LM, SEM and TEM details, some of which were not sufficiently noted in original descriptions or re-examination of type material and other specimens made by Dalu et al. [2015. A re-examination of the type material of Entomoneis paludosa (W. Smith) Reimer and its morphology and distribution in African waters. Fottea 15: 11–25] and Long et al. [2022. Ultrastructure of three species of Entomoneis (Bacillariophyta) from Lake Qinghai of China, with reference to the external areola occlusions. PhytoKeys 189: 29–50. doi:10.3897/phytokeys.189.78149].

Body composition and nutrition in skiing

Special requirements, such as super-maximally filled glycogen stores, short regeneration times, correct meal timing or appropriate weight specifications for ski jumping are particularly useful for endurance athletes such as cross-country skiers. A deficiency could have a fatal effect on performance and possibly a negative influence on health.
 While cross-country skiing is clearly one of endurance sports, ski jumping and alpine skiing are considered to be fast-strength sports or technical (acrobatic) sports.
 The proven advantages of carbohydrate loading (supercompensation), a nutritional technique for classic endurance loads, also apply to cross-country skiing.
 A drop in performance, concentration and coordination disorders as well as overheating threaten if fluid loss exceeds 2% of the total body water. Vitamin additives or sweeteners in sports drinks are inefficient. Since the higher need is actually compensated by the increased food intake with a balanced mixed diet, there is, in principle, no over-proportional need for individual vitamins in athletes.
 As the maximum oxygen uptake is already 15% lower from 3000 m altitude, a drop in performance is clearly noticeable there.
 When skiing (snowshoeing, ski touring, etc.), it should be noted that an ascent of 100 meters in altitude alone requires an additional 100–150 kcal. At moderate activity, the additional energy requirement at high altitudes compared to the sea level is estimated to be 250–290 kcal per day for men and 180–200 kcal per day for women.
 Top athletes in cross-country skiing can liberate 170–210 kJ/min (40– 50 kcal/min) in a dominant anaerobic manner within 2–3 minutes. The respective energy consumption is modified by numerous personal as well as external factors (for cross-country skiing, for example, the outside temperature, the friction resistance of the snow, the technique, the height profile of the route and the headwind).
 In cross-country skiers, the average values of body fat range between 4.8 and 12.7% in males and from 10.6 to 22.7% in females, while the average values of lean body mass (LBM) vary between 58.2 and 68.8 kg in males and from 45.6 to 48.6 kg in females. In alpine skiers, the mean values of body fat are between 9.7 and 15.8% in males and from 16.2 to 26.7% in females, and the LBM values in males range between 59.9 and 74.7 kg, in females from 42.1 to 52.8 kg. The span of body fat in male ski jumpers ranges from 8.6 to 16% with an LBM of 59.7 kg. Since 2012, a BMI of at least 21 kg/m² including suit and shoes has been a condition for ski jumpers to be able to use full-length skis (145% of body height). Otherwise, shorter skis have to be used, which reduces the wing area and is intended to reduce the jump distance as a penalty. The average values of body fat in male athletes of Nordic Combined range between 8.9 and 11.2%, and the corresponding LBM values are between 62.0 and 64.1 kg. When comparing these parameters of body composition, it must always be remembered that different methods of determining the body fat percentage have been used in corresponding studies and that possible differences do not represent a development of the skiing somatotypes over time but could also have methodological reasons.

Divergent life histories between wild and commercially-sourced Cotesia flavipes (Hymenoptera: Braconidae) parasitizing four species of Diatraea (Lepidoptera: Crambidae)

Moths of the genus Diatraea Guilding (Lepidoptera: Crambidae) are stalk-boring pests of sugarcane throughout the neotropics. In Colombia, the economically important species are D. busckella, D. indigenella, D. saccharalis, and D. tabernella. Augmentative releases of the gregarious endoparasitoid Cotesia flavipes (Cameron) are one tactic used to manage this pest complex. We compared the laboratory performance of two C. flavipes populations, one field-collected, and one commercially-sourced, on all four host species, hypothesizing lower performance of the commercial population on host species other than D. saccharalis due to continuous rearing on this species. Parasitism success did not vary with parasitoid source, but varied among host species, being highest in D. indigenella and lowest in D. tabernella, with other species intermediate. Sex ratio was female-biased, averaging 0.635, and did not vary with parasitoid source or host species. Wild wasps developed more slowly than commercial wasps on all hosts, being slowest on D. tabernella, whereas commercial wasps were slowest on D. busckella. Both parasitoid populations produced their largest broods in D. indigenella, but commercial wasps produced smaller broods than wild wasps in D. busckella and D. tabernella, and substantially lower weight gain of host larvae post-parasitism, suggesting impaired host regulation ability. In all host species, wild wasps produced larger female progeny, based on wing area, than commercial wasps. When all metrics of parasitoid performance (fitness) were combined into a single index of host suitability, D. indigenella was the most suitable host for both parasitoid populations. Both parasitoid sources had similar performance on D. saccharalis, the host used to rear the commercial population, whereas wild wasps performed better on all other Diatraea species. The inadvertant consequences of artificial selection in mass-reared cultures of gregarious endoparasitoids are discussed, specifically the evolution of faster development and smaller body size.

Treatment of full-layer skin defects using decellularized pig skin dermal matrix

The choice of treatment methods for complex skin defects poses certain technical and medical difficulties related to the choice of material for filling the wound defect and its antigenic compatibility. A promising direction in the treatment of skin defects is the use of decellularized (celluless) pig skin, the composition and structure of which is as close as possible to the patient's dermis.
 The aim of the study was to analyze the clinical case of a patient with a basal cell carcinoma in the right wing of the nose, who was treated with full-layer skin defects using a decellularized dermal matrix from pig skin.
 Material and methods of investigation. Patient P., 94 years old, with a basal cell carcinoma in the area of the right wing of the nose, underwent treatment. As a material applied directly to the wound, a flap of acellular dermal matrix (ADM) of pig skin with preservation of the native structure was used.
 Results. 6 weeks before the visit to the dermatologist, the patient developed a pea-sized papule on the skin in the area of ​​the wing of the nose, which increased in size and became painful on palpation. When examining the skin in the area of ​​the right wing of the nose, a tumor-like formation was observed, 1x1 cm in size, flesh-colored, with peeling on the surface and vascularization, firm consistency, painful. Regional lymph nodes are not enlarged. The formation is clearly separated from healthy skin. The oncologist made a diagnosis: basal cell carcinoma. The tumor was removed, resulting in a full-layer skin defect measuring 1x1.5 cm with connection to the nasal cavity. Acellular dermal matrix was used to close the defect on the 3rd day after surgery. The flap was placed so that it did not cover the skin around the wound. With the help of "Levomykol" ointment, a moist chamber was created over the dermal flap. The dressing was changed every 2-3 days. On the 14th day, the flap peeled off, a granulating wound with signs of marked marginal epithelization formed in its place. The bottom of the wound was located almost at the same level as the intact skin. On the 21st and 26th day, active marginal epithelization of the wound and wound healing under the scab were noted. The bandage was not used during this period. On the 32nd day, the wound closed.
 Conclusions. Decellularized dermal matrix of pig skin when closing a full-layer postoperative skin defect creates optimal conditions for reparative wound regeneration. The effectiveness of its use is due to the presence of a collagen matrix in it, from which the nuclear elements of cells have been removed, which does not lead to immune aggression. The clinical case proves the expediency of using the decellularized dermal matrix of pig skin in the treatment of full-layer skin defects of various genesis.