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Here we conducted wireless electrophysiological recording of hippocampal neurons from Egyptian fruit bats in the presence of human experimenters. In flying bats, many neurons modulated their activity depending on the identity of the human at the landing target. In stationary bats, many neurons carried significant spatial information about the position and identity of humans traversing the environment. Our results reveal that hippocampal activity is robustly modulated by the presence, movement and identity of human experimenters.

As natural predators, owls fly with astonishing stealth due to the serrated feather morphology that produces advantageous flow characteristics. Traditionally, these serrations are tailored for airfoil edges with simple two-dimensional patterns, limiting their effect on noise reduction while negotiating tradeoffs in aerodynamic performance. Conversely, the intricately structured wings of cicadas have evolved for effective flapping, presenting a potential blueprint for alleviating these aerodynamic limitations. In this study, we formulate a synergistic design strategy that harmonizes noise suppression with aerodynamic efficiency by integrating the geometrical attributes of owl feathers and cicada forewings, culminating in a three-dimensional sinusoidal serration propeller topology that facilitates both silent and efficient flight. Experimental results show that our design yields a reduction in overall sound pressure levels by up to 5.5 dB and an increase in propulsive efficiency by over 20% compared to the current industry benchmark. Computational fluid dynamics simulations validate the efficacy of the bioinspired design in augmenting surface vorticity and suppressing noise generation across various flow regimes. This topology can advance the multifunctionality of aerodynamic surfaces for the development of quieter and more energy-saving aerial vehicles.

Flight is a key feature of the reproduction and dispersal of emerging aquatic insects. However, morphological measurements of insect flight are mostly available for terrestrial taxa and dragonflies, while aquatic insects have been poorly investigated. We analyzed 7 flight-related morphological parameters of 32 taxa belonging to 5 orders of emerging aquatic insects (Ephemeroptera, Trichoptera, Plecoptera, Diptera, and Megaloptera) with different life history traits related to flight (dispersal strategy, voltinism, adult lifespan, and swarming behavior). After correcting for allometry, we used an a priori - free approach to cluster the individuals according to their flight-related morphology. Then, we explored the levels of agreement between these clusters, taxonomy, and several life history traits of the taxa. All orders were scattered among several clusters, suggesting a large range of flight capacities, particularly for Diptera. We found swarming taxa in each cluster, showing that morphological adaptations to swarming are not identical in all aquatic insects. The clusters did not match the expected dispersal capacity of the taxa as derived from the literature or databases. Heavy wide-winged insects notably gathered taxa traditionally described as good or weak dispersers. Flight capacities based on morphology partly matched with the taxonomy and life-history traits of aquatic insect imagoes. Other parameters such as flight propensity, energy stores, and wing kinematics should help refine their flying and dispersal capacity. [ABSTRACT FROM AUTHOR]

Copyright of Ibis is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article examines the flight dynamics and trajectory analysis of a parachute–payload system deployed from a C-17 aircraft. The aircraft is modeled with an open cargo door, extended flaps, and four turbo-fan engines operating at an altitude of 2000 feet Above Ground Level (AGL) and an airspeed of 150 knots. The payloads consist of simplified CONEX containers measuring either 192 inches or 240 inches in length, 9 feet in width, and 5.3 feet in height, with their mass and moments of inertia specified. At positive deck angles, gravitational forces cause these payloads to begin a gradual descent from the rear of the aircraft. For aircraft at zero deck angle, a ring-slot parachute with approximately 20% geometric porosity is utilized to extract the payload from the aircraft. This study specifically employs the CREATE-AV Kestrel simulation software to model the chute-payload system. The extraction and suspension lines are represented using Kestrel's Catenary capability, with the extraction line connected to the floating confluence points of the CONEX container and the chute. The chute and payload will experience coupled motion, allowing for an in-depth analysis of the flight dynamics and trajectory of both elements. The trajectory data obtained will be compared to that of a payload (without chute and cables) exiting the aircraft at positive deck angles. An adaptive mesh refinement technique is applied to accurately capture the engine exhaust flow and the wake generated by the C-17, chute, and payloads. Friction and ejector forces are estimated to align the exit velocity and timing with those recorded during flight testing. The results indicate that the simulation of extracted payloads aligns with expected trends observed in flight tests. Notably, higher deck angles result in longer distances from the ramp, leading to increased exit velocities and reduced payload rotation rates. All payloads exhibit clockwise rotation upon leaving the ramp. The parachute extraction method yields significantly higher exit velocities and shorter exit times, while the payload-chute acceleration correlates with the predicted drag of the chute as demonstrated in prior studies. [ABSTRACT FROM AUTHOR]

Bats are unique among mammals for evolving powered flight. However, very little data are available on the muscle properties and architecture of bat flight muscles. Diffusible iodine contrast‐enhanced computed tomography (diceCT) is an established tool for 3D visualisation of anatomy and is becoming a more readily accessible and widely used technique. Here, we combine this technique with gross dissection of the Egyptian fruit bat (Rousettus aegyptiacus) to compare muscle masses, fibre lengths and physiological cross‐sectional areas (PCSA) of muscles with published forelimb data from an array of non‐flying mammals and flying birds. The Egyptian fruit bat has a highly specialised pectoralis (pars posterior) architecturally optimised to generate power. The elbow flexion/extension muscles (biceps brachii and triceps brachii) have comparable PCSAs to the pectoralis, but shorter fibre lengths, which are optimised to generate large forces. Our data also show that the Egyptian fruit bat is more similar to flying birds than non‐flying mammals with its highly disparate muscle architecture. Specifically, the Egyptian fruit bat have uniquely enlarged pectoralis muscles and elbow flexion and extension muscles (bicep brachii and triceps brachii) to aid powered flight. Finally, while the Egyptian fruit bat has a comparable heterogeneity in pectoralis (pars posterior) fibre length across the cranial‐caudal axis to that seen in birds, the average normalised fibre length is larger than that seen in any of the surveyed birds. Our data here provide a greater understanding of the anatomy and functional specialisation of the forelimb musculature that powers flight. [ABSTRACT FROM AUTHOR]

This study investigates the potential of an optimized combination of active nose droop and active Gurney flap (CADAG) in a new flow control strategy to manage dynamic stall over a pitching blade section under variable Mach number flow. The optimization method employs the genetic algorithm coupled with a computational fluid dynamic (CFD) solver and artificial neural network. The base blade section belongs to a section positioned at r/R=0.865 of the rotor blade of the UH-60A helicopter in forward flight condition. A high relative angle of attack on the retreating side makes the flow susceptible to dynamic stall. A nose droop is employed to control the dynamic stall of the blade section, and a Gurney flap is used to maintain the balance of the generated lift of the blade during 360° of rotation. A comprehensive investigation is performed to determine the most significant parameters affecting the performance of the present combined active flow control. The ratio of the total generated lift to the drag is chosen as the objective function of the optimization. Results show that this ratio and the total generated lift in one rotation cycle increase by 193% and 13%, respectively, at the optimum condition of the present combined active flow control, while the ratio of the generated lift over the advancing side to the retreating side is equal to that of the base blade section. In addition, the dynamic stall hysteresis loop reduces significantly, and the maximum value of the drag coefficient and the negative aerodynamic damping decrease up to 87% and 83% compared to the base blade section, respectively. In general, the proposed innovative combined active flow control is an adjustable method to alleviate dynamic stall and improve the aerodynamic performance of rotary wings in different operation conditions. Practical Applications: The rotary blades are extensively used in rotorcraft, turbo engines, and wind turbines. Despite their massive use, they suffer from some essential issues, of which the most important one is the so-called dynamic stall. Dynamic stall is a complex phenomenon that limits the performance of the rotary blades. Due to the physics governing a rotary wing, such as a helicopter rotor blade, dynamic stall and flow separation are very common. Understanding dynamic stall physics and providing solutions to prevent it is still one of the main challenges of aerodynamic scientists. The present study introduces a novel adjustable method for practically alleviating the dynamic stall on helicopter blade section in forward flight conditions to improve its aerodynamic performance in different operational conditions. A comprehensive investigation is carried out to determine the key parameters affecting the proposed method. These findings can serve as a valuable tool for other researchers to develop various active flow control strategies. This article applies an optimization process using artificial neural networks, genetic algorithms, and CFD tools, which forms a comprehensive framework that can be easily extended to other applications. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicles (UAVs) play a very important role in military and civilian activities. In this paper, the aim is to cover the borders of Iran using UAVs. For this purpose, two zero-one programming models are presented. In the first model, our goal is to cover the borders of Iran at the minimum total time (the required time to prepare UAVs to start flying and the flight time of the UAVs). In this model, by minimizing the total time of UAVs for covering the borders, the costs appropriate to the flight of UAVs (such as the fuel costs of UAVs) are also reduced. In the second model, which is mostly used in emergencies and when a military attack occurs on the country’s borders, the aim is to minimize the maximum required time to counter attacks and cover the entire country’s borders. The efficiency of both models is shown by numerical examples. [ABSTRACT FROM AUTHOR]

Continued development of wind farms near populated areas has led to rising concerns about the potential risk posed to general aviation aircraft when flying through wind turbine wakes. There is an absence of experimental flight test data available with which to assess this potential risk. This paper presents the results of an instrumented flight experiment in which a general aviation aircraft was flown through the wake of a utilityscale wind turbine at an operating wind farm. Wake passes were flown at different downwind distances from the turbine, and data were collected on the orientation disturbances, altitude and speed deviations, and acceleration loads experienced by the aircraft. Videos and pilot statements were also collected, providing qualitative information about the disturbances encountered in the wake. Results show that flight disturbances were small in all cases, with no difference observed between flight data inside and outside the wake at distances greater than six rotor diameters from the turbine. At distances closer than six rotor diameters, small load factor and orientation disturbances were noted but were commensurate with those experienced in light or moderate atmospheric turbulence. Overall, the loads and disturbances experienced were far smaller than those that would risk causing loss of control or structural damage. [ABSTRACT FROM AUTHOR]

Background: Flying accuracy is influenced by pilots' affective reactions to task demands. A better understanding of task‐related emotions and flying performance is needed to enhance pilot training. Objective: Understand pilot trainees' performance and emotional dynamics (intensity, frequency and variability) based on training phase and difficulty level in a flight simulator. Methods: Twenty‐three volunteers performed basic flight manoeuvres. Trials were divided into three phases: Introduction (trials 1–7), session A (trials 8–15) and session B (trials 16–22). Three task difficulty levels were implemented (low, medium and high). Flying performance was evaluated using root mean square error (RMSE) and expert ratings. Emotional intensity was inferred from physiological (electrodermal activity) and behavioural (facial expressions) emotional responses. Emotional variability was calculated to understand fluctuations among multiple emotions. Emotional responses were mapped into task‐relevant emotions, like sadness with boredom, and fear with anxiety. Results and Conclusions: The most frequent facial expressions neutral, anger and surprise. Neutral and anger were interpreted as deep focus states. Surprise was likely a response to unexpected events. Flying performance and emotional dynamics varied across training phases and difficulty levels. During introduction, performance was less accurate, and emotions were less frequent. During session A, performance improved while participants experienced more physiological arousal and emotional variability. During session B, performance was the most accurate. In high‐difficulty tasks, performance was the least accurate, participants expressed emotions with more frequency, more variability and higher physiological arousal. Future studies can use simulated flying tasks for trainees to familiarize with their emotional reactions to task demands expecting to improve training outcomes. Lay Description: What is currently known about emotions in flight training?: Emotions influence pilots' decision‐making and flying accuracy.Flight simulations serve as a safe and authentic environment to develop flying skills.Emotions are dynamic processes that influence performance accuracy. What does this paper add to understanding emotions in flight training?: Flying performance improved with more practice, but it was less accurate during high difficulty manoeuvres.In simulated flight training, pilot trainees express more neutrality, anger, and surprise than happiness, fear and disgust.Pilot trainees experience more emotional fluctuations when there is no instructor feedback.Pilot trainees experience more emotional fluctuations during high difficulty flying manoeuvres. Implications for practice: Flight simulations help trainees familiarize themselves with the emotional reactions they have as training advances or encounter difficult tasks.Pilot trainees can learn emotion regulation techniques as part of their curriculum.Emotional awareness might help pilot trainees recognize key moments of disengagement or intense arousal and modify their behaviour. [ABSTRACT FROM AUTHOR]

BACKGROUND: Migration and immunity are behavioral and physiological traits that protect organisms from environmental stressors or pathogen infection. Shifting from migration to residency has become more common in some wildlife populations owing to environmental changes. However, other biological shifts, such as interactions between migration and immunity among populations within a species are largely unexplored for many agricultural migratory pests. In the field, entomopathogenic fungi infection and transmission, particularly Beauveria bassiana, can cause reduced fitness and population declines across a broad range of insect species. RESULTS: Here, we investigated migration–immunity interactions between migrant and resident populations of the oriental armyworm, Mythimna separata, infected with B. bassiana (the sole fungus used in this work). We found that migratory M. separata exerted stronger pathogen resistance, faster development and lower pupal weight than residents. High‐dose infections (5.0 × 105 and 5.0 × 106 conidia mL−1) led to seriously decreased reproductive capacity in migrants and residents. Low‐dose infections (1.0 × 104 and 5.0 × 104 conidia mL−1) led to significantly increased host flight capacities. Consecutive flight tests showed that five flight nights inhibited the reproduction of paternal infected M. separata populations. The flights also led to far‐reaching transgenerational impairment of larval development and immune defense among offspring populations. By contrast, two flight nights enhanced the reproductive capacities of both M. separata populations and did not exert negative transgenerational effects on offspring populations, which may facilitate migration. CONCLUSIONS: This study provides insights into interactions between migration and immunity among M. separata populations. These insights will guide development of future monitoring and management technologies of this pest. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In order to optimize the design of high-altitude sprinkling system of fire-fighting aircraft, it is necessary to establish a model reflecting the high-altitude spraying and distribution mechanism of mass fire extinguishing bags during the flight. Based on the discrete element method and the computational fluid dynamics method, a high-altitude spraying and distributing model of aircraft mass fire extinguishing bags is established, and the spraying characteristics and landing area distribution at different flight speeds and altitudes are obtained. The model is verified by experiments. The deviations between simulated landing distribution and experimental data are less than 20.0%. The research results provide a theoretical model for the development of aircraft high altitude fire extinguishing system, so as to significantly improve the fire extinguishing performance of aircraft spraying system.

Abstract Birds maintain some of the highest body temperatures among endothermic animals. Often deemed a selective advantage for heat tolerance, high body temperatures also limits birds’ thermal safety margin before reaching lethal levels. Recent modelling suggests that sustained effort in Arctic birds might be restricted at mild air temperatures, which may require reductions in activity to avoid overheating, with expected negative impacts on reproductive performance. We measured within-individual changes in body temperature in calm birds and then in response to an experimental increase in activity in an outdoor captive population of Arctic, cold-specialised snow buntings (Plectrophenax nivalis), exposed to naturally varying air temperatures (− 15 to 36 °C). Calm buntings exhibited a modal body temperature range from 39.9 to 42.6 °C. However, we detected a significant increase in body temperature within minutes of shifting calm birds to active flight, with strong evidence for a positive effect of air temperature on body temperature (slope = 0.04 °C/ °C). Importantly, by an ambient temperature of 9 °C, flying buntings were already generating body temperatures ≥ 45 °C, approaching the upper thermal limits of organismal performance (45–47 °C). With known limited evaporative heat dissipation capacities in these birds, our results support the recent prediction that free-living buntings operating at maximal sustainable rates will increasingly need to rely on behavioural thermoregulatory strategies to regulate body temperature, to the detriment of nestling growth and survival.

The aim of this research is to enhance adaptive autopilots for the effective management of aircraft systems, control maintenance, and the rejection of external disturbances. To achieve this objective, we propose the design of an autopilot integrated with the extremum-seeking control (ESC) algorithm. Although autopilots proficiently manage the lateral and longitudinal modes of aircraft control, they lack filtering or adaptive capabilities, thereby exposing the system to significant external threats. To mitigate these risks, the ESC method is employed. This adaptive approach can operate in a disturbance rejection manner by adjusting parameters for unknown inputs and restoring the system to its original controlled response. ESC represents a versatile control method suitable for effective application in simulations or experimental models. Through the incorporation of this method, the pitch attitude hold autopilot, altitude hold autopilot, and yaw autopilot acquire advanced disturbance rejection capabilities with adaptive ESC features. The novelty of the proposed method lies in providing advanced disturbance rejection properties to conventional autopilots, thereby rendering them innovative and superior disturbance rejection controllers. The newly developed autopilots are capable of eliminating severe disturbances from the system response, including ramp, sinusoidal, and step disturbances. The integration of autopilots with ESC offers significant advantages, such as superior disturbance rejection properties for the aircraft unmanned aerial vehicle (UAV) system. The proposed method successfully eliminates severe disturbances, as demonstrated in simulation results, surpassing previous methods in effectiveness. Furthermore, the Autopilot-ESC method enhances aircraft operation even under disturbances, minimizing energy consumption and ensuring stability and control. This novel method reduces operator workload and ensures reliable and efficient autonomous flight capabilities. Additionally, the adaptability of the Autopilot-ESC to changing environmental conditions make it well-suited in aircraft UAVs. This upgraded version of autopilot surpasses other robust controllers, such as Linear Quadratic Gaussian (LQG) regulator and Model Predictive Control (MPC), as it can effectively address ramp, sinusoidal, and step disturbances, which LQG and MPC cannot handle.

The objective of this paper is to analyze the performance of two possible architectures of tethered satellite systems, used as a platform for a distributed radar sounder. The first architecture consists in a cross-track oriented tethered satellite system, controlled and stabilized by exploiting the aerodynamic forces generated by the interaction with the rarefied atmosphere in Low Earth Orbit. The second architecture involves a tethered satellite system controlled through gyroscopic stabilization, obtained by spinning the system about an axis contained in the orbital plane. After a brief survey of radar sounding techniques, the methodology is introduced for describing the geometry of the systems and their characteristics, the performance of the two architectures are then compared with each other and with the current state of the art. By analyzing the modeled nominal behavior, it is shown that the two proposed architectures can achieve continuous or multiple observations, respectively, at maximum cross-track resolution, during one orbit, minimizing clutter noise. This is a considerable improvement of performance versus a formation flight architecture which can typically achieve only up to four observations per orbit. Finally, the advantages and disadvantages of each architecture are studied, and their possible mission scenarios are discussed. • A Tethered Satellite System is proposed, flying with tether in cross-track direction. • The tether tension is generated by aerodynamic lift forces on plates at its extrema. • Antenna elements distributed along the tether enable radar sounding applications. • Top radar sounding performances are achieved everywhere along the orbit. • An alternative gyroscopic tether system is studied for planets with no atmosphere. [ABSTRACT FROM AUTHOR]

Fixed-wing aircraft with potential for long-duration flight and efficient manoeuvrability is expected to be the next frontier of Mars surface exploration. However, the feasibility of such an aircraft demands for wing airfoil suitable for low Reynolds flight conditions. In this framework, the paper deals with the computational study of two wing sections specifically designed for Mars exploration aircraft. Two-dimensional steady Reynolds-averaged Navier–Stokes simulations, using the computational fluid dynamics tool SU2 with the γ − R e θ transition model and the XFoil panel flow solver, are performed to address airfoils' aerodynamics. Computational tools are validated by simulating flow past the Eppler 387 airfoil at R e ∞ = 60 × 1 0 3 , and comparing the results with experimental data collected in wind tunnel experiments. Aerodynamic performances of optimal wing sections are investigated at R e ∞ = 3. 4 × 1 0 4 by considering pressure coefficients and skin friction coefficients. The application of a literature-based correlation, specifically tailored to identify transition and reattachment locations, is extended to separation point detection. Computational Fluid Dynamics analysis conducted on the studied airfoils revealed that separation occurs within the laminar regime. Additionally, examination of turbulent shear stresses highlighted the role of airfoil curvature in counterbalancing the suction defect produced by the laminar separation bubble. This curvature-induced effect was found to play a crucial role in optimizing airfoil efficiency. • Aerodynamics issues of flying in Martian atmosphere. • Computation of flows past airfoils for future Mars exploration aircraft. • Detection of transition and separation at low-Reynolds number. [ABSTRACT FROM AUTHOR]

Take-off is a vital part of powered flight which likely constrains the size of birds, yet extinct pterosaurs are known to have reached far larger sizes. Three different hypothesised take-off motions (bipedal burst launching, bipedal countermotion launching, and quadrupedal launching) have been proposed as explanations for how pterosaurs became airborne and circumvented this proposed morphological limit. We have constructed a computational musculoskeletal model of a 5 m wingspan ornithocheiraean pterosaur, reconstructing thirty-four key muscles to estimate the muscle moment arms throughout the three hypothesised take-off motions. Range of motion constrained hypothetical kinematic sequences for bipedal and quadrupedal take-off motions were modelled after extant flying vertebrates. Across our simulations we did not find higher hindlimb moment arms for bipedal take-off motions or noticeably higher forelimb moment arms in the forelimb for quadrupedal take-off motions. Despite this, in all our models we found the muscles utilised in the quadrupedal take-off have the largest total launch applicable moment arms throughout the entire take-off sequences and for the take-off pose. This indicates the potential availability of higher leverage for a quadrupedal take-off than hypothesised bipedal motions in pterosaurs pending further examination of muscle forces. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, we explored the feasibility of using a transformer-based time-series forecasting architecture, known as the Temporal Fusion Transformer (TFT), for anomaly detection using threaded track data from the MITRE Corporation's Transportation Data Platform (TDP) and digital flight data. The TFT architecture has the flexibility to include both time-varying multivariate data and categorical data from multimodal data sources and conduct single-output or multi-output predictions. For anomaly detection, rather than training a TFT model to predict the outcomes of specific aviation safety events, we train a TFT model to learn nominal behavior. Any significant deviation of the TFT model's future horizon forecast for the output flight parameters of interest from the observed time-series data is considered an anomaly when conducting evaluations. For proof-of-concept demonstrations, we used an unstable approach (UA) as the anomaly event. This type of anomaly detection approach with nominal behavior learning can be used to develop flight analytics to identify emerging safety hazards in historical flight data and has the potential to be used as an on-board early warning system to assist pilots during flight. [ABSTRACT FROM AUTHOR]

Myoglobin (Mb) mediates oxygen diffusion and storage in muscle tissue and thus is important for the energy utilization and activity of animals. Birds generally have a high body temperature, and most species also possess the capability of powered flight. Both of these require high levels of aerobic metabolism. Within endothermic mammals, bats also independently evolved flight. Although the functional evolution of myoglobins in deep‐diving amniote vertebrates has been well‐studied, the functional evolution of myoglobin since the origins of both birds and bats is unclear. Here, with Mb‐coding sequences from >200 extant amniote species, we reconstructed ancestral sequences to estimate the functional properties of myoglobin through amniote evolution. A dramatic change in net surface charge on myoglobin occurred during the origin of Aves, which might have been driven by positively selected amino acid substitutions that occurred on the lineage leading to all birds. However, in bats, no change in net surface charge occurred and instead, the Mb genes show evidence of strong purifying selection. The increased net surface charge on bird myoglobins implies an adaptation to flight‐related endothermic and higher body temperatures, possibly by reducing harmful protein aggregations. Different from the findings of net surface charge, myoglobins of extant birds show lower stability compared with other amniotes, which probably accelerates the rate of oxygen utilization in muscles. In bats and other mammals, higher stability of Mb may be an alternative pathway for adaptation to endothermy, indicating divergent evolution of myoglobin in birds and bats. [ABSTRACT FROM AUTHOR]

In the United States, the Federal Aviation Administration has officially classified flight crews (FC) consisting of commercial pilots, cabin crew, or flight attendants as "radiation workers" since 1994 due to the potential for cosmic ionizing radiation (CIR) exposure at cruising altitudes originating from solar activity and galactic sources. Several epidemiological studies have documented elevated incidence and mortality for several cancers in FC, but it has not yet been possible to establish whether this is attributable to CIR. CIR and its constituents are known to cause a myriad of DNA lesions, which can lead to carcinogenesis unless DNA repair mechanisms remove them. But critical knowledge gaps exist with regard to the dosimetry of CIR, the role of other genotoxic exposures among FC, and whether possible biological mechanisms underlying higher cancer rates observed in FC exist. This review summarizes our understanding of the role of DNA damage and repair responses relevant to exposure to CIR in FC. We aimed to stimulate new research directions and provide information that will be useful for guiding regulatory, public health, and medical decision-making to protect and mitigate the risks for those who travel by air. [ABSTRACT FROM AUTHOR]

In this work, typical design, production, and testing procedures for a small unmanned helicopter are explained and performed. In doing so, preliminary sizing of the helicopter and three main disciplines are conducted: aerodynamic analytical and numerical simulations, power calculations, and structure analysis assessment. First, a thorough survey is implemented to obtain the trends for the maximum take-off weight versus some design constraints such as rotor diameter, motor power, payload, and empty weight. Performance calculation results are obtained to figure out all aspects that correspond to the specified mission. The designed rotor geometry along with the aerodynamic characteristics and flight performance variables is then validated using the blade element theory and numerical simulations. Second, based on the power curves obtained for different flight regimes, an electric brushless motor is selected. The numerical simulations (Computational Fluid Dynamics) analysis is used to enhance the selection which implies that the motor power should be greater than 5.4 kW to overcome the drag forces. The motor power selection corresponds to a maximum rotor pitch angle of 15∘ and a maximum rotor speed of 1450 RPM. Then, the aerodynamic loads are used as an input for the structural analysis using one-way coupling of fluid–structure interaction (FSI) and consequently designing the internal structure of the blade. Eventually, the internal structure manufactured using carbon fiber-reinforced polymer (CFRP) by applying a combined technique between wet layup and compression molding. The blade is statically tested compared with numerical finite element model results. The fuselage structure along with hub and tail units is manufactured and assembled with the existing on-shelf components to examine the helicopter lift capability with different payloads up to 9 kg. The results show that the detailed design process is significant for manufacturing such blades and the helicopter is capable of lifting off the ground with various payloads depending on the rotor pitch angles (8∘, 12∘, and 15∘) at a constant rotor speed of 1450 RPM. [ABSTRACT FROM AUTHOR]

Birds maintain some of the highest body temperatures among endothermic animals. Often deemed a selective advantage for heat tolerance, high body temperatures also limits birds' thermal safety margin before reaching lethal levels. Recent modelling suggests that sustained effort in Arctic birds might be restricted at mild air temperatures, which may require reductions in activity to avoid overheating, with expected negative impacts on reproductive performance. We measured within-individual changes in body temperature in calm birds and then in response to an experimental increase in activity in an outdoor captive population of Arctic, cold-specialised snow buntings (Plectrophenax nivalis), exposed to naturally varying air temperatures (− 15 to 36 °C). Calm buntings exhibited a modal body temperature range from 39.9 to 42.6 °C. However, we detected a significant increase in body temperature within minutes of shifting calm birds to active flight, with strong evidence for a positive effect of air temperature on body temperature (slope = 0.04 °C/ °C). Importantly, by an ambient temperature of 9 °C, flying buntings were already generating body temperatures ≥ 45 °C, approaching the upper thermal limits of organismal performance (45–47 °C). With known limited evaporative heat dissipation capacities in these birds, our results support the recent prediction that free-living buntings operating at maximal sustainable rates will increasingly need to rely on behavioural thermoregulatory strategies to regulate body temperature, to the detriment of nestling growth and survival. [ABSTRACT FROM AUTHOR]

The purpose of this article is to analyse Elena Garro's poetry compiled in Cristales de tiempo (2008) from a hermeneutical point of view. For biographical reasons, the Mexican author's lyrical production has been relegated to a second line within the 20th century Latin American poetics. For this reason, in this paper we examine some of her most significant poems, highlighting her adherence to a surrealist aesthetic in which the lyrical voice finds no possible refuge other than escape to other realities. [ABSTRACT FROM AUTHOR]

The PEGASUS study is the first multicentric and prospective assessment of the safety of air travel flying in pulmonary hypertension (PH) (NCT03051763). Data of air travel from 60 patients with PH was available. No severe adverse events occurred. Nine patients self‐reported mild adverse events during flight (13%), while after landing, 12 patients reported events (20%). Solely one patient (2%) had an adverse event leading to medical consultation. In patients with PH and World Health Organization functional classes II and III, air travel was safe. [ABSTRACT FROM AUTHOR]

Movement is a key behaviour to better understand how individuals respond to their environment. Movement behaviours are affected by both extrinsic factors that individuals face, such as weather conditions, and intrinsic factors, such as sex and experience. Because of the energy costs it entails, movement behaviours can have direct consequences on an individual's demographic parameters—and ultimately on population dynamics. However, the relationship between extrinsic factors, intrinsic factors, daily movement behaviour and demographic parameters such as breeding performance is poorly known, in particular for central place forager territorial species. We investigated here the link between movement behaviours and breeding performance of the French population of Bonelli's eagle (Aquila fasciata), a territorial and sedentary long‐lived raptor, and how this link may depend on extrinsic and intrinsic factors. By using data from annual monitoring of breeding performance for the population and GPS tracking of 48 individuals (26 males and 22 females), we found that the breeding performance of this population was mainly driven by whether a new individual was recruited into the territory, and only slightly by weather conditions. Movement behaviours (proportion of time in flight, range of movement and straightness of trajectories) showed large between‐individual variation. Those behaviours were related with weather conditions (wind and rainfall) at a daily scale, as well as with individual's experience. We found only one significant correlation between movements and breeding performance: male Bonelli's eagles spending more time flying during chick‐rearing phase had lower productivity. Movement behaviours and breeding performance were also indirectly linked through individual's experience, with more experienced birds having better breeding success and a shorter range of movement and spent less time in flight. This suggests that experienced individuals progressively acquire knowledge of their breeding territory, are more efficient in finding prey, and adapt their foraging strategies to weather conditions to minimise energy costs, allowing them higher breeding performance. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of nonviolent action in situations of armed conflict has been labelled as the 'new frontier' in resistance studies. This paper assesses the growing body of literature on civilian resistance against rebel groups. Drawn from a systematic review of academic articles, book chapters, and policy documents, examples of civilian resistance are ordered in three distinct categories of unarmed action: deception; dissent; and defiance. This classification provides the conceptual framework to tackle the main research question: does civilian resistance against rebels work to protect unarmed populations from violence and harm? By scrutinising the effectiveness of civilian resistance, the paper seeks to provide a necessary corrective to the dominant view expressed in the literature, which, as argued, is overly optimistic regarding the prospects of wringing substantial concessions from armed groups via nonviolent action. The paper concludes with a discussion of policy implications, focusing on normative challenges facing external actors eager to support civilian resisters. [ABSTRACT FROM AUTHOR]

In order tomake detailed and accurate predictions of aircraft noise around airports, we have developed "J-FRAIN", a new aircraft noise simulation framework that can precisely predict the time histories of noises emitted from each major aircraft noise source during the landing approach phase at ground observation points. This article describes the elements of the developed framework--data acquisition, sound source modeling, propagation modeling, and ground noise prediction--and present some application examples. To develop the framework, we first deployed a 30m-diameter microphone array under the final approach path to an international airport to measure acoustic maps of several civil aircraft types in flight. The sound powers of major aircraft noise-emitting componentswere then estimated quantitatively by domain integration of the deconvolved acoustic maps at five emission angles in the plane of the glideslope, and the directivities of each noise sourcewere determined. Next, componentwise sound source regression models for engines and airframe noise sourceswere created based on the physical relationships between engine rotation speed, airspeed, and the deployment angle of high-lift devices, and the coefficients in each modelwere determined to minimize the root-mean-square error between themeasured and predicted sound power levels. The phenomena of atmospheric absorption and ground effect during the propagation of radiated sounds were also incorporated into the framework. Actual flight parameter values were used as inputs to the completed framework, and it was confirmed that the predicted time histories of sound pressure levels on the ground agreed with measured data towithin 2 dB if ground effect was properly considered. Finally, as sample applications that use the unique features of the proposed J-FRAIN framework, the article discusses the evaluation of the contributions of each aircraft noise source at noise observation points under the final approach path to the airport and the impact assessment of flight operations on noise. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Modular organization in brain regions often performs specific biological functions and is largely based on anatomically and/or functionally related brain areas. The current study aimed to explore changes in whole-brain modular organization affected by flight training. METHODS: The study included 25 male flight cadets and 24 male controls. The first assessment was performed in 2019, when the subjects were university freshmen. The second assessment was completed in 2022. High spatial resolution structural imaging (T1) and resting-state functional MRI data were collected. Then, 90 cerebral regions were organized into 6 brain modules. The intensity of intra- and intermodular communication was calculated. RESULTS: Mixed-effect regression model analysis identified significantly increased interconnections between the parietal and occipital modules in the cadet group, but significantly decreased interconnections in the control group. This change was largely attributed to flight training. DISCUSSION: Pilots need to control the aircraft (e.g., attitude, heading, etc.) using the stick and pedal in response to the current state of the aircraft displayed by the instrument panel; as such, flying requires a large amount of hand-eye coordination. Day-to-day flight training appeared to intensify the connection between the parietal and occipital modules among cadets. [ABSTRACT FROM AUTHOR]

An insect's wingbeat frequency is a critical determinant of its flight performance and varies by multiple orders of magnitude across Insecta. Despite potential energetic benefits for an insect that matches its wingbeat frequency to its resonant frequency, recent work has shown that moths may operate off their resonant peak. We hypothesized that across species, wingbeat frequency scales with resonance frequency to maintain favourable energetics, but with an offset in species that use frequency modulation as a means of flight control. The moth superfamily Bombycoidea is ideal for testing this hypothesis because their wingbeat frequencies vary across species by an order of magnitude, despite similar morphology and actuation. We used materials testing, high-speed videography and a model of resonant aerodynamics to determine how components of an insect's flight apparatus (stiffness, wing inertia, muscle strain and aerodynamics) vary with wingbeat frequency. We find that the resonant frequency of a moth correlates with wingbeat frequency, but resonance curve shape (described by the Weis-Fogh number) and peak location vary within the clade in a way that corresponds to frequency-dependent biomechanical demands. Our results demonstrate that a suite of adaptations in muscle, exoskeleton and wing drive variation in resonant mechanics, reflecting potential constraints on matching wingbeat and resonant frequencies. [ABSTRACT FROM AUTHOR]

This article investigates the causes of occasional flight instability observed in Unmanned Aerial Vehicles (UAVs). The issue manifests as unexpected oscillations that can lead to emergency landings. The analysis focuses on delays in the Extended Kalman Filter (EKF) algorithm used to estimate the drone's attitude, position, and velocity. These delays disrupt the flight stabilization process. The research identifies two potential causes for the delays. First cause is magnetic field distrurbances created by UAV motors and external magnetic fields (e.g., power lines) that can interfere with magnetometer readings, leading to extended EKF calculations. Second cause is EKF fusion step implementation of the PX4-ECL library combining magnetometer data with other sensor measurements, which can become computionally expensive, especially when dealing with inconsistent magnetic field readings. This can significantly increase EKF processing time. The authors propose a solution of moving the magnetic field estimation calculations to a separate, lower-priority thread. This would prevent them from blocking the main EKF loop and causing delays. The implemented monitoring techniques allow for continuous observation of the real-time operating system's behavior. Since addressing the identified issues, no significant problems have been encountered during flights. However, ongoing monitoring is crucial due to the infrequent and unpredictable nature of the disturbances. [ABSTRACT FROM AUTHOR]

Exoplanet atmospheres are expected to vary significantly in thickness and chemical composition, leading to a continuum of differences in surface pressure and atmospheric density. This variability is exemplified within our Solar System, where the four rocky planets exhibit surface pressures ranging from 1 nPa on Mercury to 9.2 MPa on Venus. The direct effects and potential challenges of atmospheric pressure and density on life have rarely been discussed. For instance, atmospheric density directly affects the possibility of active flight in organisms, a critical factor since without it, dispersing across extensive and inhospitable terrains becomes a major limitation for the expansion of complex life. In this paper, we propose the existence of a critical atmospheric density threshold below which active flight is unfeasible, significantly impacting biosphere development. To qualitatively assess this threshold and differentiate it from energy availability constraints, we analyze the limits of active flight on Earth, using the common fruit fly, Drosophila melanogaster, as a model organism. We subjected Drosophila melanogaster to various atmospheric density scenarios and reviewed previous data on flight limitations. Our observations show that flies in an N2-enriched environment recover active flying abilities more efficiently than those in a helium-enriched environment, highlighting behavioral differences attributable to atmospheric density vs. oxygen deprivation. [ABSTRACT FROM AUTHOR]

Optimal migration theory prescribes adaptive strategies of energy, time or mortality minimization. To test alternative hypotheses of energy- and time-minimization migration we used multisensory data loggers that record time-resolved flight activity and light for positioning by geolocation in a long-distance migratory shorebird, the little ringed plover, Charadrius dubius. We could reject the hypothesis of energy minimization based on a relationship between stopover duration and subsequent flight time as predicted for a time minimizer. We found seasonally diverging slopes between stopover and flight durations in relation to the progress (time) of migration, which follows a time-minimizing policy if resource gradients along the migration route increase in autumn and decrease in spring. Total flight duration did not differ significantly between autumn and spring migration, although spring migration was 6% shorter. Overall duration of autumn migration was longer than that in spring, mainly owing to a mid-migration stop in most birds, when they likely initiated moult. Overall migration speed was significantly different between autumn and spring. Migratory flights often occurred as runs of two to seven nocturnal flights on adjacent days, which may be countering a time-minimization strategy. Other factors may influence a preference for nocturnal migration, such as avoiding flight in turbulent conditions, heat stress and diurnal predators. [ABSTRACT FROM AUTHOR]

In order to update the information on horseflies in the Balearic Islands, five sites in Mallorca were sampled in 2022 and 2023 with traps and sweep netting. A total of 479 specimens belonging to five species were identified: Hybomitra expollicata (Pandellé, 1883), Tabanus autumnalis Linnaeus, 1761, Tabanus bromius Linnaeus, 1758, Tabanus flavofemoratus Strobl 1908 and Tabanus miki Brauer, 1880. The former species represents the first record of this genus for the Balearic Islands. In addition, new Balearic records of T. flavofemoratus and T. miki are also provided. With these new contributions, the horsefly fauna in Mallorca comprises a total of nine species. [ABSTRACT FROM AUTHOR]

A numerical method for generating dynamic stall using ANSYS Fluent and a user-defined function (UDF), with the complete script shared for reference, is introduced and tested. The study draws inspiration from bird flight, exploring dynamic stall as a method for achieving enhanced aerodynamic performance. The numerical method was tested on NACA 0012 airfoils with corresponding chord lengths of c 1 = 40   m m , c 2 = 150   m m , and c 3 = 300   m m at Reynolds numbers ranging from R e 1 = 2.8 × 10 4 up to R e 5 = 1.04 × 10 6 . Airfoil oscillations were settled for all cases at ω = 0.55   H z . Detached eddy simulation (DES) is employed as the turbulence model for the simulations presented, ensuring the accurate representation of the flow characteristics and dynamic stall phenomena. The study provides a detailed methodology, encouraging further exploration by researchers, especially young academics and students. [ABSTRACT FROM AUTHOR]

Laser wake field acceleration (LWFA) is limited by some determinative aspects, such as wave breaking, dephasing, pulse divergence, etc. One of the proposed methods to overcome the acceleration limitations of the LWFA is spatio-temporal controlling of the laser focus, named flying focus. In this article, flying focus dynamics for two Bessel beam profiles is derived with complex source point method (CSPM). We investigate the two pulse with basic Gaussian and Donut-like profiles, those focal points move at a speed very close to the speed of light. Our selected flying focus parameters maintain laser intensity up to 16 times the Rayleigh length (− 8ZR, + 8ZR). We also examined the flying focus LWFA (FF-LWFA) energy gain and trapping rate for these two cases. Numerical results show that accelerated electron bunch is converged considerably for the Donut shape profile. This convergence is due to the inward radial ponderomotive force, and furthermore suitable phase difference between longitudinal and transverse wake field components. Since electrons are hold near the axis for a longer distance and keep more energy from the wake. In average 2.8% of the injected electrons are accelerated up to 255 MeV for the donut-like profiles, while only 1.4% of electrons are accelerated up to 155 MeV for Gaussian profile. [ABSTRACT FROM AUTHOR]

The history of slavery in the age of abolition is full of contradictions. The fate of enslaved persons depended on coincidences, on bad luck and good fortune. To understand what this meant in practice, this article focuses on questions of flight and longing. It zooms in on the colonial enclave Manado, North Sulawesi (Indonesia), where slavery was both an indigenous-regional and a local-colonial phenomenon, two worlds that were never fully separated. This exploration centers around two sets of archives: a slave register and a series of interviews with runaways. These fascinating documents were produced at the same time and in the same space, but provides us markedly different perspectives. What do they tell us about motives and experiences of people who escaped slavery? To what extend can we reconstruct life in and out of slavery when we combine these two sets of sources? The critical exploration that this article presents is meant as a step towards a fuller comprehension of the history of slavery in colonial Indonesia. [ABSTRACT FROM AUTHOR]

Simple Summary: Pest control plays an important role in crop production. The cotton leafworm, Spodoptera litura, is well recognized as a pest that causes severe damage to a wide variety of crops. Because S. litura is nocturnal, it is challenging to control this species effectively. Recently, laser zapping has gained attention as a clean technology to control pest insects. It is important to precisely identify and predict the flight trajectories of free-flying moths under low-light conditions for better sighting during laser zapping. In this study, we developed an automatic detection pipeline based on point cloud time series data from stereoscopic images. Three-dimensional point cloud data were extracted from disparity images recorded under infrared and low-light conditions. We computed the size of the outline box and the directional angle of the 3D point cloud time series to remove noisy point clouds. We visually inspected the flight trajectories and found that the size and direction of the outline box were good indicators of the noisy data. Finally, we obtained 68 flight trajectories, and the average flight speed of free-flying S. litura was found to be 1.81 m/s. Pest control is crucial in crop production; however, the use of chemical pesticides, the primary method of pest control, poses environmental issues and leads to insecticide resistance in pests. To overcome these issues, laser zapping has been studied as a clean pest control technology against the nocturnal cotton leafworm, Spodoptera litura, which has high fecundity and causes severe damage to various crops. For better sighting during laser zapping, it is important to measure the coordinates and speed of moths under low-light conditions. To achieve this, we developed an automatic detection pipeline based on point cloud time series data from stereoscopic images. We obtained 3D point cloud data from disparity images recorded under infrared and low-light conditions. To identify S. litura, we removed noise from the data using multiple filters and a support vector machine. We then computed the size of the outline box and directional angle of the 3D point cloud time series to determine the noisy point clouds. We visually inspected the flight trajectories and found that the size of the outline box and the movement direction were good indicators of noisy data. After removing noisy data, we obtained 68 flight trajectories, and the average flight speed of free-flying S. litura was 1.81 m/s. [ABSTRACT FROM AUTHOR]

A sports dart pierces the dartboard because it possesses a remarkable aerodynamic property of 'self-correcting' its attitude in flight. This property arises from its aerodynamic design with a long heavy Barrel and large cruciform wings known as flights. We characterize the aerodynamics of dart-shaped projectiles at typical flight Reynolds numbers between 14500 and 20500 using wind tunnel experiments and numerical simulations. Force measurement tests from wind tunnel experiments yield the lift, drag, and pitching moment coefficients over a range of angles of attack; the experimental estimates are in quantitative agreement with those obtained from numerical simulations. Examining the surface pressure distribution, streamlines, and wall shear–stress distribution, along with the skin friction lines obtained from numerical simulations, reveals that the aerodynamics of the dart is governed by an interaction between the Barrel vortex (BV) shed by the cone–cylinder body and the wing leading edge vortex (WLV) over the horizontal flights influenced by solid impediment offered by the vertical flights. Smoke flow visualization images corroborate the vortex–vortex and vortex–wall interactions over the flights found in the numerical simulations. A complex interplay of vortex structures is observed, which depends on the angle of attack. The WLV develops an elliptic instability while exhibiting a partial merger with the Barrel vortex in the presence of secondary vorticity generated by the walls amidst the rapid weakening of the WLV. We conclude that the role of aerodynamics is largely pitch stabilization by means of aerodynamic moment and the normal force generation. [ABSTRACT FROM AUTHOR]

This paper takes a new look at how the aerodynamic interactions of multiple bodies in high-speed flow affect their motion behaviors. The influence of the body shape and orientation on aerodynamic and stability behavior in the case of shock–shock and wake–shock interactions is the focus of this publication. Experiments were performed in the hypersonic wind tunnel H2K at the German Aerospace Center (DLR) in Cologne. Free-flight tests with tandem arrangements of spheres and cubes were performed with a synchronized dropping of both objects at various initial conditions of relative streamwise and vertical distance as well as pitch angle. A high-speed stereo-tracking captured the model motions during free-flight, and high-speed schlieren videography provided documentation of the flow topology. Based on the measured 6-degrees-of-freedom (6DoF) motion data, aerodynamic coefficients were determined. As a result, the final lateral velocity of trailing cubes is found to be many times greater than that of spheres regarding shock-wave surfing. For rotating cubes, the results showed that stable shock-wave surfing can become possible over an increasingly wide range of initial positions. This study has identified that the trailing drag coefficient of two axially aligned objects varies strongly with their relative streamwise distance. Furthermore, it was shown that the wake is a region of stability for downstream objects. [ABSTRACT FROM AUTHOR]

Although diurnality is widespread across Lepidoptera and has evolved many times independently, its causes and ecological implications are yet poorly understood. The "Salient Aroma Hypothesis" (SAH) postulates that diurnal insect herbivores are overall more specialized in dietary breadth than species active at night. It is furthermore assumed that diurnality evolved more frequently in species that live in cooler environments. Using European geometrid moths as a model group, we tested whether diurnal activity in adults is associated with an increased larval dietary breadth as predicted by the SAH. We further investigated whether species that exclusively occur in colder regions or whose flight period is restricted to cool seasons are more likely to exhibit a diurnal flight activity. Contrary to expectation, we found no consistent differences in larval dietary breadth between diurnal and nocturnal species, and thus no support for the SAH. Diurnal activity occurred more frequently in species restricted to cold regions but not in species restricted to cool seasons. We conclude that diurnality could serve as an advantageous adaptation in cold environments, depending on further factors such as resource availability or predation pressure, but has no immediate consequences for larval dietary breadth. [ABSTRACT FROM AUTHOR]

The perceptual range of an organism is the distance at which landscape elements are recognised by it. Estimates of this sensory trait are relevant to understand how organisms recognise suitable habitat within fragmented landscapes.We investigated how the nature of inhospitable environments (matrix) neighbouring a forest patch and adult experience (lab‐raised naïve vs. free‐flying experienced adults) affect the perceptual range and flight speed of the forest butterfly species Heliconius erato and Heliconius melpomene.In field experiments, butterflies were released at various distances from the edge of the habitat patch. Flight orientation and speed were evaluated. In one experiment, wild‐caught individuals of H. erato and H. melpomene were released in two matrix types, a coconut plantation and an open field. In a subsequent experiment, lab‐raised naïve H. erato was released at the same site.Release distance was the best predictor of butterfly behaviour for the two species. Individuals released up to 60 m successfully oriented towards the habitat patch, indicating a perceptual range below 100 m. Flight speed was higher the closer a butterfly was released to the edge. Matrix type did not affect butterfly orientation within its perceptual range distance. We did not find a significant effect of experience on butterfly orientation.Our study shows that the perceptual distance of Heliconius is within the range of known estimates from other butterfly species. Within this range, and irrespective of matrix type and experience, individuals were capable of orienting towards their preferred habitat and at flight speeds that were related to the distance of release. [ABSTRACT FROM AUTHOR]

The skeletons and surrounded plumages aura fossil of Confuciusornis sanctus discovered in early Cretaceous lacustrine sedimentary stata in western Liaoning Province, China shed new light on the early evolution of their avian flight as follows: (1) Confuciusornis sanctus' sternums were weak and less keeled, a signal its poor flight aptitude, while a modern skillful flying bird's sternum is strong and carinate with bulky pectoral flight muscles accounting for more than 20 percent of the body weight. (2) Confuciusornis sanctus 7 forelimbs possess three flexible digits with large and sickle-like claws apt for tree climbing yet decreased flying function. In contrast to the corresponding positions of the modern sophisticated flying birds, it possessed an alula for regulating the flow of air passing the surfaces of the wings to ensure smoothly and avoid the stall at a large angle of incidence during taking off or landing. On the other hand, Confuciusornis sanctus exhibited some advanced features: CD Confuciusornis sanctus7 portable toothless horny beaks suited to pecking; a shorten tail of only 8 caudal vertebrae and a pygostyle for attachment of the fan-like tail feathers, providing critical surfaces, beneficial to controlling flight direction and speed instantly, especially during taking off and landing; an inflated evidently proximal part of the humerus which had an oval depression, perhaps showing an air sac system, lightened the structural weight of the skeleton. (2) Confuciusornis sanctus had developed feather system, almost same to the modern flying birds and beneficial to flight. The wing-shape of a Confuciusornis sanctus was short and broad as that in a chicken-like bird, indicating possible similar flight manner. [ABSTRACT FROM AUTHOR]

The commercial and operations planning in airlines has traditionally been a hierarchical process starting with flight schedule design, followed by fleet assignment, aircraft rotation planning and finally the crew scheduling. The hierarchical planning approach has a drawback that the optimal solution for a planning phase higher in hierarchy may either be infeasible for the subsequent phase or may lead to a sub‐optimal overall solution. In this paper, we solve a profit‐maximizing integrated planning model for clean‐sheet "rotated" schedule design with flight re‐time option and crew scheduling for a low‐cost carrier (LCC) in an emerging market. While the aircraft rotation problem has been traditionally modeled in the literature as a daily routing of individual aircraft for maintenance requirement, in this work we address the requirement of planned aircraft rotations as part of schedule design for LCCs. The planned aircraft routing is important in our case to create as many via‐flights as possible due to the underserved nature of the emerging market. We solve this large‐scale integer‐programming problem using two approaches – Benders Decomposition and Lagrangian Relaxation. For Lagrangian Relaxation, we exploit the special structure of our problem and intuitive understanding behind the Lagrangian duals to develop a multiplier adjustment approach to find an improved lower bound of integrated model solution. The crew‐pairing sub‐problem is solved using column generation through multi‐label shortest path algorithm followed by branch‐and‐price for integer solution. We test our solution methodology on a flight universe of 378 unique flights for different problem sizes by varying the number of aircraft available for operations. Our computational results show that within a reasonable run time of few hours both the approaches, Benders Decomposition and Lagrangian Relaxation, are successful in finding lower bounds of the integrated model solution, which are higher than the solution of traditional hierarchical approach by 0.5%–2.5%. We find Lagrangian Relaxation methodology to usually attain an improved solution faster than the Benders Decomposition approach, particularly for large‐scale problems. [ABSTRACT FROM AUTHOR]

Models of aircraft trajectories become important components of systems supporting the trajectory based operations paradigm: trajectory predictability is considered to be the main driver to enhance operational key performance areas, such as capacity of the airspace, effectiveness regarding all stakeholders' objectives, and, of course, safety. This article formulates the trajectory modelling problem as a data-driven imitation learning problem addressing multi-modality. To solve this problem we study the use of state-of-the-art multi-modal imitation learning methods Info-GAIL and Triple-GAIL operating in a supervised way, with the aim of (a) disentangling modalities representing patterns of trajectory evolution, and (b) predicting trajectories. Experiments are performed using a real-world dataset of long flights with origin Paris and destination Istanbul. Results show the potential of imitation learning methods to disentangle multi-modal trajectories in real-world settings and predict trajectories with high accuracy. [ABSTRACT FROM AUTHOR]

Featured Application: The proposed method can be utilized to determine whether an aircraft encountered turbulence during or after flight, rather than relying on EDR estimation to ascertain turbulence encounters. By integrating swarm intelligence and machine learning and adopting a data-driven approach to turbulence identification, the method addresses previous challenges encountered in turbulence identification, thereby enhancing the efficacy of aviation safety. This approach demonstrates a certain degree of applicability in improving aviation safety. Turbulence is a significant operational aviation safety hazard during all phases of flight. There is an urgent need for a method of airline turbulence identification in aviation systems to avoid turbulence hazards to aircraft during flight. Integrating flight data and machine learning significantly enhances the efficacy of turbulence identification. Nevertheless, present studies encounter issues including unstable model performance, challenges in data feature extraction, and parameter optimization. Hence, it is imperative to propose a superior approach to enhance the accuracy of turbulence identification along airline. The paper presents a combined swarm intelligence and machine learning model based on data mining for identifying airline turbulence. Based on the theory of swarm-intelligence-based optimization algorithm, the optimal parameters of Categorical Boosting (CatBoost) are obtained by introducing the whale optimization algorithm (WOA), and the corresponding WOA-CatBoost fusion model is established. Then, the Recursive Feature Elimination algorithm (RFE) is used to eliminate the data with lower feature weights, extract the effective features of the data, and the combination with the WOA brings robust optimization effects, whereby the accuracy of CatBoost increased by 11%. The WOA-CatBoost model can perform accurate turbulence identification from QAR data, comparable to that with established EDR approaches and outperforms traditional machine learning models. This discovery highlights the effectiveness of combining swarm intelligence and machine learning algorithms in turbulence monitoring systems to improve aviation safety. [ABSTRACT FROM AUTHOR]

Reactions to the Wright brothers' achievement of the first sustained, controlled powered flight in December 1903 ranged from complete indifference to voluble celebration and evolved into convictions that ranged from a belief that war would be rendered impossible to confident predictions of invasion and widespread destruction. The policies and perceptions of institutions, governments and individuals were subject to constant revision and often abrupt reversal. When war came, the aeroplane, which began as an instrument of reconnaissance, rapidly became one more hazard among many for those at the front and a further point of division between combatants and civilians, for whom airships and air raids tended to loom larger. The first dynamic phase in the story of the aeroplane overlaps with the major early modernist period. This essay seeks to map, within that wider context, the experiences and responses of Ford Madox Ford. He began, like many others, with images of beauty and the natural world in that early stage when a functioning range of descriptive or comparative terms had yet to emerge. He encountered them next in the theatre of war during his service in France. His ambivalence towards aeroplanes was both similar to and different from his earlier responses to trains, cars and telephones. Their relative rarity, as well as their both physical and metaphorical distance, and Ford's own apparent immunity to the glamour and dynamism of aviation enabled him to view them retrospectively and employ them in anecdote, autobiography and fiction as both threat and saviour. [ABSTRACT FROM AUTHOR]

The vast majority of pterosaurs are characterized by relatively large, elongate heads that are often adorned with large, elaborate crests. Projecting out in front of the body, these large heads and any crests must have had an aerodynamic effect. The working hypothesis of the present study is that these oversized heads were used to control the left–right motions of the body during flight. Using digital models of eight non-pterodactyloids ("rhamphorhyncoids") and ten pterodactyloids, the turning moments associated with the head + neck show a close and consistent correspondence with the rotational inertia of the whole body about a vertical axis in both groups, supporting the idea of a functional relationship. Turning moments come from calculating the lateral area of the head (plus any crests) and determining the associated lift (aerodynamic force) as a function of flight speed, with flight speeds being based on body mass. Rotational inertias were calculated from the three-dimensional mass distribution of the axial body, the limbs, and the flight membranes. The close correlation between turning moment and rotational inertia was used to revise the life restorations of two pterosaurs and to infer relatively lower flight speeds in another two. [ABSTRACT FROM AUTHOR]