bluuebunny/crossref_metadata_2025 huggingface dataset:
The relationship between naturalized alien and native plant species: insights from oceanic islands of the south-east Pacific over the last 200 years
Authors: Cáceres-Polgrossi Luis , Di Rico Maura , Parra Diego , Seebens Hanno , Galvin Stephen D. , Boehmer H. Juergen
Published: July 2023

Aim: The relationship between native and naturalized alien species has been widely studied, particularly across large geographic scales. However, our knowledge of the spatial and temporal variations of their relationships is still limited, particularly for remote oceanic islands such as those of the south-east Pacific and across islands and archipelagos. In this study, we aim to assess the relationships between native and naturalized alien species by analyzing their current patterns of species-area relationships at different spatial scales, in addition to temporal variations in species richness, over the last 200 years.

Area: One island (Rapa Nui) and two archipelagos (Juan Fernandez and Desventuradas Islands) comprising a total of 11 oceanic islands of the south-east Pacific (OISEP).

Methods: We assembled the most comprehensive dataset of the vascular flora of the OISEP from currently available island flora checklists and updated with recent publications. Each plant species was classified as being native or naturalized alien. We examined temporal changes by estimating species richness, naturalization rates and naturalized-to-native ratios over time based on the first collection year of each naturalized alien species. Then, we determined the best shape of naturalized alien species richness accumulation over time by contrasting the fit of lineal, exponential, sigmoidal and Weibull regressions. Finally, we analyzed the relationships between native and naturalized species firstly at the inter-archipelagic scale by fitting island species-area relationship models and secondly at the island scale by performing ranged major axis regression analysis on residual values.

Results: The OISEP flora dataset contained 674 species of which 282 were native and 392 were naturalized alien. Native island species-area relationships were similar to those of the naturalized alien species. Naturalized alien species richness increased notably through time with two clear peaks in 1950 and 2000. A Weibull regression and an exponential shape over time were the most appropriate fits for naturalized alien species richness accumulations at the inter-archipelagic scale, which further emphasizes the notable increase in naturalized alien species richness experienced in the timeframe examined here.

Main conclusions: The relationship between naturalized alien species richness and native species richness was found to be independent of the geographic scale. The number of naturalized alien species clearly exceeded the number of native species on most islands but also for the whole OISEP. The accumulation of newly detected naturalized alien species does not show any sign of saturation and it is likely that new species will arrive in the future. Increased efforts on monitoring, prevention and biosecurity are needed to halt biological invasions on these unique island ecosystems.
Advances in the Evaluation of Peripheral Enthesitis by Magnetic Resonance Imaging in Patients With Psoriatic Arthritis
Authors: Østergaard Mikkel , Maksymowych Walter P.
Published: July 2023

Enthesitis is a key disease manifestation in patients with psoriatic arthritis (PsA) that considerably contributes to pain, lower physical function, and reduced quality of life. Clinical assessment of enthesitis lacks sensitivity and specificity, and therefore better methods are urgently needed. Magnetic resonance imaging (MRI) allows detailed assessment of the components of enthesitis, and consensus-based validated MRI scoring systems exist. These include the Outcome Measures in Rheumatology (OMERACT) Heel Enthesitis MRI Scoring System (HEMRIS) method, which assesses the entheses of the heel region in a detailed manner, and the OMERACT MRI Whole-Body Score for Inflammation in Peripheral Joints and Entheses (MRI-WIPE) method, which provides an overall assessment of the inflammatory burden in the peripheral entheses and joints in the entire body using whole-body MRI. At an MRI workshop at the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2022 meeting in Brooklyn, the MRI appearances of peripheral enthesitis were described, as were the scoring methods. The utility of MRI for improved assessment of enthesitis was demonstrated with examples of patient cases. Clinical trials in PsA that evaluate enthesitis by MRI as a key endpoint should include the presence of MRI enthesitis as an inclusion criterion, and apply validated MRI outcomes to assess the effect of therapeutics on enthesitis are recommended.
Rapid Improvement in Lipid Maculopathy Following Faricimab Therapy in Recalcitrant Familial Exudative Vitreoretinopathy
Authors: Ghoraba Hashem H. , DeBoer Charles , Moshfeghi Darius M.
Published: July 2023

A monocular 22-year-old man with recalcitrant familial exudative vitreoretinopathy presented with progressive subretinal lipid exudation and lipid maculopathy that responded poorly to repeated aflibercept injections. The subretinal exudation started temporally and gradually progressed, involving the macula and the retinal periphery in all 4 quadrants. At the 22-month follow-up visit, macular and peripheral subretinal exudation persisted despite a total of 29 injections. Faricimab was then injected once every 2 weeks for a total of 3 injections, which resulted in rapid dramatic resolution of the macular and most of the peripheral subretinal exudation. No ocular or systemic adverse events were noted.

[
Ophthalmic Surg Lasers Imaging Retina
2023;54:426–428.]
Clinical Factors and Outcomes of Acute-Onset Endophthalmitis Following Small-Gauge Pars Plana Vitrectomy Surgery
Authors: Vagaggini Tommaso , Adams Olufemi E. , Curran Christian D. , Prairie Michael L. , Baker Mikayla J. , Sastry Ananth , Ryan Edwin H. , Parke D. Wilkin , Mittra Robert A. , Tang Peter H.
Published: July 2023

Background and Objectives:

Describe risk factors, findings, and outcomes of acute endophthalmitis (AE) following small-gauge pars plana vitrectomy (PPV).

Patients and Methods:

This was a retrospective single-center, nonrandomized study of post-PPV AE patients from 2013 to 2021. All received vitreous biopsy before treatment. Patients were divided into cohorts: 1) PPV within 3 days of diagnosis (Urgent-PPV), and 2) no urgent PPV (Other-treatment [Tx]). Main outcome was best-corrected visual acuity (BCVA) at 6 months.

Results:

Twenty-one patients were analyzed. Epiretinal membrane was the most common indication for PPV (48%). Incidence was 0.074%. Culture-positive rate was 57%. For final BCVA, there was no significant (
P
= 0.85) difference between Urgent-PPV (median = 0.40 logMAR) and Other Tx cohorts (median = 0.35 logMAR). Sclerotomy wounds were not sutured in 71% of patients. Approximately 24% and 38% of patients analyzed had either no tamponade or partial tamponade, respectively.

Conclusion:

Tamponade agents and sclerotomy suturing may be important factors when evaluating post-small-gauge PPV-associated AE. Further studies are necessary for clarification.

[
Ophthalmic Surg Lasers Imaging Retina
2023;54:395–400.]
A Review of Novel Anesthetic Technique for Vitreoretinal Surgery
Authors: Dodson Steven , Wang Rui , Todorich Bozho
Published: July 2023

Background and Objective:

Currently, there is no standardized formulation of intravenous anesthetic that exists for vitreoretinal surgery. We describe a novel anesthetic protocol for vitreoretinal surgery that is safe and effective for patients and surgeons alike.

Study Design:

Review the current challenges to vitreoretinal anesthetic technique and descriptive overview outlining the proposed anesthetic protocol and associated experience with technique.

Results:

The proposed anesthetic technique utilizes a sub-tenon peribulbar block with a continuous propofol infusion. A low dosage continuous propofol infusion provides patients with profound anxiolysis and relaxation while maintaining wakefulness. Fentanyl can be additionally titrated for patients that report symptoms of pain or increased respiratory rate.

Conclusion:

A low dose propofol infusion in combination with sub-tenon peribulbar block and judicious use of fentanyl provide an ideal operative condition for ambulatory vitreoretinal surgery.

[
Ophthalmic Surg Lasers Imaging Retina
2023;54:429–431.]
Common fixed and coincidence point theorems for nonlinear self-mappings in cone $ b $-metric spaces using $ \varphi $-mapping
Authors: Song Mingliang , Liu Dan
Published: July 2023

In this paper, by means of a mapping $ \varphi\in\Phi(P, P_1) $, some new common fixed and coincidence point theorems for four and six nonlinear self-mappings in cone $ b $-metric spaces are established, respectively. Also, some examples are given to prove the effectiveness of our results. And with some remarks stating that our results complement and sharply improve some related results in the literature.
Design and assessment of a vision computing-based multimedia interaction system for hybrid teaching
Authors: Cui Zhan , Chu Jinjin
Published: July 2023

Hybrid teaching is a novel education mode that combines both online activities and offline activities. The main technical point is to facilitate the interaction between online and offline scenarios. The vision computing acts as the most intuitive way for this purpose. As a consequence, this paper designs a vision computing-based multimedia interaction system for hybrid teaching, and makes some empirical evaluation. It is composed of two parts: design and evaluation. For the former, macroscopic architecture of the interaction system is presented, and fundamental protocol for video transmission and analysis is defined. On this basis, an optimal scheduling algorithm that coordinates collaborative work of several modules is designed. For the latter, a prototype system is developed for experimental simulation to test abilities of both visual information processing and interactive scheduling. The results show that the designed multimedia interaction system can well implement hybrid teaching affairs under the guarantee of remote interaction performance.
Solving problems involving numerical integration (I): Incorporating different techniques
Authors: Guo William
Published: July 2023

Numerical integration plays an important role in solving various engineering and scientific problems and is often learnt in applied calculus commonly through the trapezium and Simpson's methods (or rules). A common misconception for some students is that Simpson's method is the default choice for numerical integration due to its higher accuracy in approximation over the trapezium method by overlooking the requirement for using Simpson's method. As learning progressed to other numerical methods scheduled later in advanced mathematics, such as interpolations and computational modelling using computing tools like MATLAB, there is a lack of articulation among these numerical methods for students to solve problems solvable only by combining two or more approaches. This classroom note shares a few teaching and learning practices the author experienced in lectures, tutorials, and formal assessments on comparing or combining different numerical methods for numerical integration for engineering students in applied calculus and advanced mathematics over the past decade at Central Queensland University (CQU), a regional university in Australia. Each case represents a common concern raised or a mistake made by some students in different times. These efforts helped not only correct the misconception on the use of Simpson's method by some students, but also develop students' strategic thinking in problem solving, particularly involving decision-making for choosing the best possible method to produce a more appropriate solution to a problem that does not have an analytical solution.
Augmented Reality Awareness and Latest Applications in Education: A Review
Authors: Oueida Soraia , Awad Pauly , Mattar Claudia
Published: July 2023

Several advances in technology have touched the educational sector, where improvements and enhancements are always a surge for innovative learning. Augmented Reality (AR) is considered an efficient and promising technology capable of enhancing the educational sector. AR is a visualization technology that allows human interaction by providing users with a perception of reality using virtual information. In other words, AR adds to the existing real-world environment some extra virtual information generated by computer techniques that can enhance the overall experience. This promising technology can be applied in different sectors such as education, healthcare, banks, tourism, etc. Despite the great work available in the literature about this topic, deep insights and extensive research are still needed before the actual implementation in the real world. The aim of this work is to highlight the importance of AR in improving the educational sector and increase awareness of using such an approach. A review is conducted to prove the validity of AR in increasing learning outcomes, students’ motivation, and engagement in classrooms, as well as improving the understanding level. Several papers were analyzed based on different application areas under various interdisciplinary databases. As a result, the papers were collected in a table-based format to provide researchers with better and easier insights on how to improve the use of AR in education before real implementation. This study helped in highlighting potential future work, discussing limitations, advantages, disadvantages, and the latest advances in this technology.
Mettre l’intime en bande dessinée. Un dialogue avec Léna Merhej et Noémie Honein
Authors: De Giacometti Michela , Odasso Laura
Published: July 2023

Cet entretien rend compte de l’échange que nous avons eu avec Noémie Honein et Léna Merhej – deux artistes libanaises particulièrement connues pour leurs travaux en bande dessinée – au sujet de leurs trajectoires, ainsi que de leurs quêtes, interrogations et pratique artistiques. Leurs parcours, singuliers et témoignant de générations différentes, convergent dans leur volonté de mettre en récit et en dessin l’intimité. Dans De l’importance du poil de nez, Noémie Honein explore son expérience de la maladie, alors qu’à l’âge de vingt ans elle apprend être atteinte d’un cancer. La mise en récit de cette période de sa vie, sous forme de bande dessinée, s’apparente à un voyage à la découverte de ses relations intimes : celles qu’elle entretient avec sa famille et celles qu’elle développe avec son corps qui se métamorphose au fur et à mesure des thérapies. Elle interroge ainsi son rapport à la sexualité, également affectée par la maladie. Née d’une mère allemande et d’un père libanais, Léna Merhej consacre l’un de ses premiers travaux Laban et confiture, ou comment ma mère est devenue Libanaise à narrer une intimité familiale traversée par la guerre du Liban (1975-1990), la reconstruction du pays, et encore la guerre de l’été 2006. Elle y explore la question des identités plurielles dans la pratique du quotidien et joue habilement avec les stéréotypes d’une prétendue identité libanaise. En 2007, Léna Merhej fonde au Liban, avec trois autres artistes et dessinateurs, la revue Samandal (« salamandre » en arabe), dont la vocation est d’être, à l’image de cet amphibien, une entité hybride. Il s’agit, à l’origine, d’un projet expérimental destiné à soutenir la publication d’œuvres de ce premier groupe d’artistes. La revue se transforme rapidement en un collectif et élargit ses horizons pour inclure les bandes dessinées d’autres artistes du monde arabe et d’ailleurs. En 2016, Samandal publie en France, pour des raisons de censure, aux éditions Alifbata, le numéro intitulé Ça restera entre nous : un ouvrage sans fard sur le thème de la sexualité qui offre des planches illustrées, dans quatre langues (arabe, français, anglais et italien), de 27 artistes internationaux. Lever le voile sur les expériences singulières des corps – celles de la sexualité et celles de la maladie – invite à explorer les contextes dans lesquels celles-ci prennent forme : les vécus personnels de ces femmes sont en effet intimement mêlés à des conjonctures politiques et à l’expérience collective. Ces deux artistes – qui vivent désormais entre la France et le Liban – se racontent, parlent de leur famille et dressent aussi le portrait de leur pays d’origine, le Liban.
Dichten in zwei Sprachen: Rilkes literarische Zweisprachigkeit aus textgenetischer Sicht
Authors: Hartmann Esa Christine
Published: July 2023

Rainer Maria Rilke est l’un des rares écrivains de renommée internationale du début du xxe siècle qui a grandi dans un environnement multilingue et multiculturel, appris plusieurs langues au cours de sa vie, en les transformant, à travers ses créations littéraires, en un idiome poétique. Dans le contexte de cette identité multilingue et multiculturelle de Rilke, cet article se consacre au processus de création franco-allemand du poète, en examinant les différentes manifestations créatrices de son bilinguisme poétique. Explorant le processus d’écriture bilingue, voire translingue, de Rilke à travers la genèse des Cahiers de Malte Laurids Brigge, cette analyse à la fois génétique et poétologique s’appuie sur un corpus avant-textuel, réunissant le brouillon (« Arbeitsliste ») précédant le manuscrit des Cahiers (« Berner Taschenbuch »), la version finale de l’œuvre, ainsi que les annotations que Rilke consacre à la traduction française des Cahiers par Maurice Betz.
Raoul Hausmann ou la subversion des identités nationales
Authors: Thiérard Hélène
Published: July 2023

Cet article analyse la production littéraire franco-allemande de Raoul Hausmann, notamment après l’exil de 1933. Ayant fui l’Allemagne nazie, l’ancien dadaïste berlinois trouve refuge en France où il restera jusqu’à sa mort en 1971. Faisant, à partir de 1945, du français sa seconde langue d’écriture, il adopte une stratégie de bilinguisme alterné qui vise à le faire reconnaître parallèlement comme écrivain allemand et comme écrivain français. Il s’agit ici d’une posture auctoriale scindée, conforme à la logique des littératures nationales, alors qu’à la même époque Hausmann élabore dans des livres majeurs comme Hyle II ou PIN une poétique plurilingue farouchement opposée à l’idéologie des identités nationales et à leur supposée homogénéité culturelle. À travers l’analyse de Hyle, Ein Traumsein in Spanien, auquel Hausmann travaille de 1933 à 1958, on éclairera la tension qui existe entre ces deux pratiques du plurilinguisme après 1945.
Annette, ein Heldinnenepos d’Anne Weber
Authors: Aurenche-Beau Emmanuelle
Published: July 2023

L’article traite du livre d’Anne Weber Annette, ein Heldinnenepos (2020). Il étudie la manière dont il présente à un public allemand une « héroïne » très française, en l’inscrivant non seulement dans son contexte géographique, social et historique, mais aussi dans son contexte linguistique, par l’insertion dans le texte allemand de termes français particulièrement représentatifs et expressifs. Il montre également comment, en recourant à une forme comme l’épopée qui suppose une forme de communication particulière entre l’auteur et son public, Anne Weber crée une situation qui lui permet de jouer avec les deux versions du texte, la version allemande et la version française qui en est davantage une réécriture qu’une traduction au sens strict. La réflexion sur l’héroïsme et l’engagement qui parcourt le livre, quant à elle, confère au livre une dimension universelle.
Quality Tools and Their Applications in Industry
Authors: Ifrim Ana Maria , Silvestru Cătălin Ionuț , Stoica Mihai-Alexandru , Icociu Cristina Vasilica , Oncioiu Ionica , Lupescu Marian Ernuț
Published: July 2023

Almost all quality improvement methods require data collection and analysis to solve quality problems. The combination of six sigma and agile creates a six sigma agile methodology that aims to reach quality levels according to the Six Sigma requirements of 3.4 defects per million measurements. In order to achieve these objectives, it is necessary to know the industry well and implicitly the product or the analysed process. Thus, the correctness of these analyses depends on the collection of the data that will be analysed. The use of data analysis methods at each stage, especially in the measurement and analysis stages, is critically important for making strong decisions. The purpose of this article is to present the added value of the integration of six sigma and agile methodologies for IT projects. Thus, the integration of the two methodologies will lead to faster decision-making without the risk of an increase in the number of failures.
The Mechanism of Flipped Classroom Based on Cognitive Schemas
Authors: Zhu Wangyihan
Published: July 2023

The flipped classroom has achieved great success in Europe and America. This study aims to provide theoretical basis for the flipped classroom in the perspective of cognia theoretical. It reviewed a large amount of literature, induced, and analyzed the developmental mechanism of flipped classroom, providing theoretical and practical references for teaching renovation in China. It was concluded that through brief teaching videos, courseware, and online communicative platform, the flipped classroom facilitates self-directed learning, and constructs cognitive schemas to pave solid foundation for connection between updated and outdated information, and assimilation and adaptation of cognitive schemas, leading to success in learning and teaching. The flipped pedagogical model also facilitates the construction of individualized cognitive schemas by highlighting discussion rather than written assignment after class. Nevertheless, the preview prior to class and in-class lecturing in the traditional classroom fails to function in this way.
Activation Mechanism of CcGSDMEb-1/2 and Regulation for Bacterial Clearance in Common Carp (Cyprinus carpio)
Authors: Zhao Yanjing , Qiao Dan , Zhang Jie , Gao Feng , Pei Chao , Li Chen , Kong Xianghui
Published: July 2023

Gasdermin E (GSDME), to date, is considered the only direct executor of the pyroptosis process in teleost and plays an important role in innate immunity. In common carp (Cyprinus carpio), there contains two pairs of GSDME (GSDMEa/a-like and GSDMEb-1/2), and the pyroptotic function and regulation mechanism of GSDME still remain unclear. In this study, we identified two GSDMEb genes of common carp (CcGSDMEb-1/2), which contain a conserved N-terminal pore-forming domain, C-terminal autoinhibitory domain, and a flexible and pliable hinge region. We investigated the function and mechanism of CcGSDMEb-1/2 in association with inflammatory and apoptotic caspases in Epithelioma papulosum cyprinid cells and discovered that only CcCaspase-1b could cleave CcGSDMEb-1/2 through recognizing the sites 244FEVD247 and 244FEAD247 in the linker region, respectively. CcGSDMEb-1/2 exerted toxicity to human embryonic kidney 293T cells and bactericidal activity through its N-terminal domain. Interestingly, after i.p. infection by Aeromonas hydrophila, we found that CcGSDMEb-1/2 were upregulated in immune organs (head kidney and spleen) at the early stage of infection, but downregulated in mucosal immune tissues (gill and skin). After CcGSDMEb-1/2 were knocked down and overexpressed in vivo and in vitro, respectively, we found that CcGSDMEb-1/2 could govern the secretion of CcIL-1β and regulate the bacterial clearance after A. hydrophila challenge. Taken together, in this study, it was demonstrated that the cleavage mode of CcGSDMEb-1/2 in common carp was obviously different from that in other species and played an important role in CcIL-1β secretion and bacterial clearance.
Handling Qualities Assessment of Large Variable-RPM Multi-Rotor Aircraft for Urban Air Mobility
Authors:   Rensselaer Polytechnic Institute, Bahr Matthew , Gandhi Farhan , McKay Michael , Niemiec Robert
Published: July 2023

Optimization-based control design techniques are applied to multicopters with variable-RPM rotors. The handling qualities and motor current requirements of a quadcopter, hexacopter, and octocopter with equal gross weights (1200 lb) and total disk areas (producing a 6 lb/ft2 disk loading) are compared to one another in hover. For axes that rely on the rotor thrust (all except yaw), the increased inertia of the larger rotors on the quadcopter increase the current requirement, relative to vehicles with fewer, smaller rotors. Both the quadcopter and hexacopter have maximum current margin requirements (relative to hover) during a step command in longitudinal velocity. In yaw, rotor inertia is irrelevant, as the reaction torque of the motor is the same whether the rotor is accelerating or overcoming drag. This, combined with the octocopter’s greater inertia as well as the fact that it requires 30% less current to drive its motors in hover, results in the octocopter requiring the greatest current margin, relative to hover conditions. To meet handling qualities requirements, the total weight of the motors of the octocopter and hexacopter is comparable at 15% weight fraction, but the quadcopter’s motors are heavier, requiring 17% weight fraction. If the longitudinal and lateral axes were flown in ACAH mode, rather than TRC mode, the total motor weight of all configurations would be nearly identical, requiring about 14.6% weight fraction for motors (compared to 8-9% weight fraction from hover torque requirements).
Aerodynamic Investigation of Non-Planar Wing Configurations for Quadrotor Based Tail-Sitters
Authors:   University of Maryland, Safieh Derek , Chopra Inderjit , Hrishikeshavan Vikram
Published: July 2023

Optimization-based control design techniques are applied to multicopters with variable-RPM rotors. The handling qualities and motor current requirements of a quadcopter, hexacopter, and octocopter with equal gross weights (1200 lb) and total disk areas (producing a 6 lb/ft2 disk loading) are compared to one another in hover. For axes that rely on the rotor thrust (all except yaw), the increased inertia of the larger rotors on the quadcopter increase the current requirement, relative to vehicles with fewer, smaller rotors. Both the quadcopter and hexacopter have maximum current margin requirements (relative to hover) during a step command in longitudinal velocity. In yaw, rotor inertia is irrelevant, as the reaction torque of the motor is the same whether the rotor is accelerating or overcoming drag. This, combined with the octocopter's greater inertia as well as the fact that it requires 30% less current to drive its motors in hover, results in the octocopter requiring the greatest current margin, relative to hover conditions. To meet handling qualities requirements, the total weight of the motors of the octocopter and hexacopter is comparable at 15% weight fraction, but the quadcopter’s motors are heavier, requiring 17% weight fraction. If the longitudinal and lateral axes were flown in ACAH mode, rather than TRC mode, the total motor weight of all configurations would be nearly identical, requiring about 14.6% weight fraction for motors (compared to 8-9% weight fraction from hover torque requirements).
Comparing RotCFD Predictions of the Multirotor Test Bed with Experimental Results
Authors:   NASA Ames Research Center, Conley Sarah , Kallstrom Kristen , Koning Witold , Romander Ethan , Russell Carl
Published: July 2023

The Multirotor Test Bed (MTB) is a new capability for testing a wide array of advanced vertical take-off and landing (VTOL) rotor configurations, with a primary focus on testing in the U.S. Army 7- by 10-Foot Wind Tunnel at NASA Ames Research Center. The MTB was designed to allow adjustment of the vertical, lateral, and longitudinal placement of each rotor, as well as allow tilt adjustment of each rotor and pitch adjustment of the whole assembly. Each rotor can tilt forward 90 deg and backwards 5 deg. In addition, the entire MTB can tilt forward 20 deg and backwards 10 deg. This flexibility allows the system to be tested in many different configurations. There is a six-axis load cell under each rotor assembly, to measure both the steady and dynamic loads produced by each rotor. The wind tunnel scales can measure loads on the full assembly. The overall goal of the MTB project is to help gain a better understanding of the performance, control, interactional aerodynamics, and acoustics of multirotor systems. A hybrid CFD tool called RotCFD (Rotorcraft Computational Fluid Dynamics) was used to simulate the MTB in several testing configurations. This paper explains the method of running the RotCFD simulations and explores the results from the simulations. The objective of this paper is to compare the RotCFD simulation results with the MTB wind tunnel test data, seeking to further validate RotCFD for multirotor systems and assess the influence of aerodynamic interactions on individual rotor performance.
Development of an Air-launched Tail-Sitter Unmanned Aerial Vehicle
Authors:   Texas A&M University, Cai Jiaze , Denton Hunter , Benedict Moble
Published: July 2023

This paper describes the development and flight testing of the first-ever air-launched tail-sitter UAV platform. Integrated with VTOL capability, the platform can be launched from various platforms, perform long-endurance loiter tasks and low-speed or hover flight, and land vertically in limited spaces. This work covers the experimental exploration of possible rotatable-fin designs, which then converge to a coaxial thrust vectoring design. A platform featuring a coaxial propeller and a thrust-vectoring mechanism is combined with a conventional fixed-wing design to accomplish both vertical and horizontal flights. An innovative bird-wing-inspired wing folding mechanism is also proposed in this work. A control strategy capable of handling both vertical and horizontal flight has been proposed. A cascaded feedback control strategy was implemented on a 1.7-gram custom-designed autopilot to stabilize the vehicle attitude. The proposed platform uses the coaxial rotors and the thrust-vectoring mechanism to accomplish the control in pitch, roll, and yaw for both vertical and horizontal flight. An indoor flight test with aggressive pilot inputs was successfully performed to demonstrate the controllability of the aircraft. Additionally, transition flight testing has successfully demonstrated the vehicle's capability of transition flight using the proposed thrust-vectoring mechanism.
Effects of Light Rain on Coaxial and Tandem Rotor Performance in Hover
Authors:   Georgia Institute of Technology, Gahlot Aishwerya ,   ANSYS Inc., Chen Po-Wei , Sankar Lakshmi
Published: July 2023

With the advent of the new generation of eVTOL helicopters and UAS systems, there has been an increased interest in designing and modeling compact multi-rotor systems that provide the required lift and thrust forces, and control moments. These systems would be expected to be available and operate in adverse weather that includes light rain in warm and cold weather. Towards this need, an existing hybrid Navier-Stokes/free wake model has been enhanced to tightly couple the transport of water droplets with the aerodynamic flow, taking into consideration the drag force exerted by the airstream on the water droplets, and the reaction forces exerted by the droplets on the air flow. In this study, this coupled solver is used to model the effects of rain on coaxial and tandem rotors operating in hover. A coaxial rotor tested by Harrington and a tandem rotor tested by Sweet are considered. The aerodynamic performance (thrust and power coefficients, and the figure of merit) are presented as a function of the rotor collective pitch and compared with computational and experimental data in the absence of rain. The incremental effects of rain on the rotor thrust and power are quantified.
Towards CFD Simulations of Transient Tiltrotor Conversion Maneuvers
Authors:   Ames Research Center, Tran Steven , Yeo Hyeonsoo , Lim Joon , Wissink Andrew
Published: July 2023

This paper details the progress made towards using Computational Fluid Dynamics/Comprehensive Analysis (CFD/CA) coupled simulations to model transient tiltrotor conversion maneuvers from hover to cruise. Recently the availability of Helios' mid-fidelity tool ROAM has enabled Cartesian-based CFD simulations of full aircraft in reasonable compute times. In this work, ROAM is tightly coupled to RCAS which allows for transient conversion maneuvers to be dynamically computed based on realistic aerodynamic loads. Both a 30 second and 45 second conversion maneuver are analyzed using this method. Quasi-steady comparisons between ROAM and traditional high-fidelity CFD tools Overflow and Fun3D demonstrate that though ROAM underestimates rotor power, it predicts more realistic loads than an RCAS standalone model using dynamic inflow. This is due to ROAM's ability to capture blade/vortex interactions and rotor/wing interactional aerodynamics, which in turn led to more realistic structural load predictions during both the quasi-steady and transient conversion maneuver simulations. Furthermore, ROAM is up to 52x faster than traditional high-fidelity methods.
Numerical and Experimental Assessment of Parameters Influencing the Development of Secondary Vortex Structures in Rotor Wakes
Authors:   Science and Technology Corporation, Bodling Andrew ,   German Aerospace Center - DLR, Schwarz Clemens , Wolf C. , Gardner Anthony
Published: July 2023

A common phenomenon in modern high-fidelity CFD simulations is the breakdown of the primary vortex system in hover due to secondary vortex braids. In the current work, the development of secondary vortex structures in the wake of a two-bladed rotor was investigated by combining stereoscopic particle image velocimetry measurements in different measurement planes and high-fidelity simulations. An analysis was performed to investigate how various numerical inputs including sub-iteration convergence, numerical dissipation, blade pitch offset, grid-resolution, and rotor thrust affect the primary and secondary vortex characteristics. A parametric study on near- and off-body solver sub-iteration convergence demonstrated that the primary and secondary vortex characteristics converge as the sub-iteration convergence of both solvers increase. The breakdown of the primary vortex was shown to be directly linked to the number of secondary vortices. Dissimilarities in the blade pitch angle, which could not be avoided in the experiment, were modeled by intentionally using an offset in the blade pitch angle of the two blades. It was shown that as blade pitch angle offset increases, vortex pairing becomes more distinct. When vortex pairing occurred in both the experiment and simulation, the decay of secondary vortices in the experiment and simulation agreed best. Grid resolution was decreased from 5% chord to 3% chord, and the finer mesh simulation with higher sub-iteration convergence agreed best with the measured primary and secondary vortex characteristics. Differences in the measured and predicted number of secondary vortices for the lower thrust case was attributed to differences in tip vortex breakdown in the experiment and simulation.
Prediction of the Laminar-to-turbulent Transition Position on a Helicopter Rotor Blade with Cyclic Pitch Variation
Authors:   ONERA - The French Aerospace Lab, Richez Francois ,   US Army CCDC AvMC, Jain Rohit
Published: July 2023

This work aims at assessing different laminar-to-turbulent transition models with different CFD codes for unsteady cases of a helicopter rotor with cyclic pitch variation. ONERA evaluates with elsA code the semi-empirical transition criteria-based approach and the Langtry-Menter model, while US Army investigates two versions of the Langtry-Menter model available in the Helios/Overflow code. The experimental transition position measurements provided by DLR show a complex hysteretic behavior of the transition front motion. The simulations show that Langtry-Menter model can reproduce this hysteresis with a satisfactory agreement, if spatial accuracy is maximized using refined meshes and minimized numerical dissipation. The numerical results are then used to identify the transition mechanisms involved and the unsteady effects at the origin of hysteresis.
Flight Testing of Optimal Blade for a High-Speed Helicopter
Authors:   JAXA, Kimura Keita , Sugiura Masahiko , Sugawara Hideaki , Tanabe Yasutada
Published: July 2023

In this paper, flight demonstration of the feasibility of an optimal rotor blade designed by JAXA for high-speed helicopters and the single-rotor lift-offset technology using flap differentials on the fixed-wing is reported, conducted using a 1/7 scale model helicopter named HARIOS. Flight speed of the model helicopter was measured by equipping a pitot tube and static pressure ports, and the power consumption during forward flight was obtained by summing the power consumption of various motors. These results were then compared. Although the flight demonstration was limited to an advance ratio of 0.4, it was observed that the acceleration of the aircraft increased when equipped with JAXA's optimal blade, and a significant reduction in power consumption occurred when applying the lift-offset technique. This marks a milestone in the test-flight verification for the two technologies, which had previously been investigated through wind tunnel tests and Computational Fluid Dynamics (CFD) simulations. With this flight demonstration, a significant step towards validating the effectiveness of the JAXA optimal rotor blade design and single-rotor lift-offset technology has been taken.
Chronic Exertional Compartment Syndrome Resolved With Running Gait Retraining: A Case Report
Authors: Allison Abigail K. , Ishikawa Kirsten L. , Gerber John Parry , Dewing Christopher
Published: July 2023

A 34-year-old female athlete experienced pain, tightness, and sensation changes in her lower legs and feet when reaching approximately 1 mile (1.6 km) of her run. After a wick catheter test, an orthopaedic surgeon diagnosed her with chronic exertional compartment syndrome (CECS) and declared her eligible to undergo fasciotomy surgery. A forefoot gait is theorized to delay the symptom onset of CECS and decrease the amount of discomfort the runner experiences. The patient opted for a 6-week gait retraining program to try to alleviate her symptoms nonsurgically. The purpose of our report is to provide information about the contributing factors of CECS and to determine if gait retraining is an effective alternative to invasive surgery. After 6 weeks of gait retraining, the patient was able to run without experiencing any CECS symptoms. Also, her compartment pressures were reduced, leading the surgeon to no longer recommend fasciotomy.
О некоторых свойствах решений систем дифференциальных уравнений с переключением
Authors: Ignatyev Alexander Olegovich
Published: July 2023

Рассмотрен важный класс гибридных систем, называемых системами с переключением, в которых непрерывный процесс регулируется дискретным управлением между различными подсистемами. В случае, когда система с переключением имеет периодическое решение, получена оценка снизу величины его периода. Для линейного дифференциального уравнения второго порядка с переключением доказано неравенство, позволяющее оценить расстояние между двумя последовательными нулями его решения.
Библиография: 33 названия.
Об ограниченности максимальных операторов, ассоциированных с сингулярными гиперповерхностями
Authors: Usmanov Salim Eshimovich
Published: July 2023

В статье рассматриваются максимальные операторы, связанные с семейством сингулярных гиперповерхностей в пространстве $\mathbb{R}^{n+1}$. Доказана ограниченность этих операторов в пространстве суммируемых функций в случае, когда гиперповерхности задаются параметрическими уравнениями. Найден показатель ограниченности максимальных операторов для пространств суммируемых функций.
Библиография: 20 названий.
MARKET TIMING E CRIAÇÃO DE VALOR PARA OS ACIONISTAS SOB A PERSPECTIVA DA RETENÇÃO DE CAIXA
Authors: Januário Alessandro Henrique De Araújo , Tavares Adilson De Lima
Published: July 2023

Esta pesquisa tem por objetivo investigar a relação entre a retenção de caixa e a criação de valor para os acionistas das empresas que utilizam o IPO como momento oportuno para o comportamento de market timing no mercado acionário brasileiro. A amostra do estudo consiste em 102 empresas não financeiras listadas na B3 que realizaram IPO entre 2004 e 2017, segregadas em dois grupos, timers e non-timers de mercado. No total, 202 IPOs ocorreram no decorrer do período delimitado, ademais, o comportamento do caixa foi analisado durante os oito trimestres subsequentes aos IPOs, resultando em 816 observações. Para atingir o objetivo, são propostos dois modelos econométricos, um para cada hipótese formulada, e o método de análise de dados utilizado é regressão em painel dinâmico com estimadores GMM-System de um estágio. Os dados financeiros, necessários para os cálculos das variáveis que compõem os modelos econométricos, foram coletados por meio da base Refinitiv Eikon®. As evidências da estimação do Modelo I confirmam a primeira hipótese, isto é, timers de mercado retêm mais caixa que non-timers. Por sua vez, os achados da estimação do Modelo II são inconclusivos, dado que a variável explanatória apresenta insignificância estatística, motivo pelo qual não é possível determinar a existência de uma relação entre retenção de caixa e criação de valor para os acionistas. Todavia, apesar de reter, em média, mais caixa que os non-timers, conforme evidenciado pelo Modelo I, as empresas que utilizam o IPO como momento oportuno para o comportamento de market timing no mercado acionário brasileiro apresentam menor valor criado para os acionistas, conforme demonstrado pelo Modelo II, haja vista que o MVA dos timers de mercado cresce 247 milhões (R$) de um período para o outro, enquanto que o crescimento médio das empresas non-timers é de 534 milhões (R$) de um período para o outro, uma diferença de 287 milhões (R$). É possível que tal resultado derive do alto custo de oportunidade do caixa ocioso, pois, como o market timing trata-se de uma prática oportunista, os gestores, em geral, não têm destinação imediata para o recurso constituído.
SOFT SKILLS NO ENSINO DE GRADUAÇÃO EM CIÊNCIAS CONTÁBEIS
Authors: Bassani Fernanda Michele , Martins Marco Antônio dos Santos , Farias, Msc. Everton Da Silveira
Published: July 2023

Este artigo apresenta como as habilidades não técnicas, denominadas Soft Skills, estão sendo contempladas no ensino superior de Ciências Contábeis. Desenvolveu-se um conjunto de etapas para realizar a investigação deste tema, triangulando diferentes fontes de dados relativas à problemática de pesquisa traçada. Na Etapa 1, realizou-se uma Revisão Sistemática da Literatura (RSL), na qual foram identificadas 16 Soft Skills que embasam este estudo. Na Etapa 2, utilizou-se de pesquisa documental, a partir de 12 Projetos Pedagógicos de Cursos (PPCs) de graduação em Ciências Contábeis. Nas Etapas 3 e 4, foram aplicados questionários, utilizando a técnica de coleta Survey, com dez coordenadores de Curso e 142 estudantes de graduação em Ciências Contábeis de Instituições de Ensino Superior públicas e privadas. Foram realizadas análises estatísticas utilizando o software IBM SPSS Statistics©. Os resultados apresentam as principais Soft Skills abordadas nos cursos de graduação em Ciências Contábeis e a percepção de coordenadores de curso e de estudantes em relação ao grau de importância e ao nível de desenvolvimento das Soft Skills no período de formação. Os resultados contribuem no campo profissional, evidenciando potencializar determinadas Soft Skills na formação dos profissionais contábeis, tais como: “Inteligência emocional” e “Persuasão”. No campo acadêmico, a pesquisa amplia os estudos sobre Soft Skills no ensino contábil, trazendo quais competências não técnicas são percebidas como importantes para a atuação do profissional contábil: “Trabalho em Equipe”, “Comunicação Eficaz” e “Resolução de Problemas”. Por fim, no aspecto pedagógico, a pesquisa apresenta um panorama de como os projetos pedagógicos de Ciências Contábeis estão contemplando as Soft Skills em seus currículos, o que pode auxiliar os Núcleos Docentes Estruturantes (NDEs) na elaboração de projetos pedagógicos que potencializem o desenvolvimento das Soft Skills nos estudantes de contabilidade.
APLICAÇÃO DE MÉTODOS ÁGEIS NA ADOÇÃO DE NORMAS CONTÁBEIS: O CASO DA ADOÇÃO DA IFRS 16 NA PETROBRAS
Authors: Farias Juliana Aguiar , Santos Odilanei Morais
Published: July 2023

Com o processo de convergência às normas internacionais de contabilidade (IFRS), a partir de 2010, observou-se a publicação de diversas normas, exigindo das empresas grandes esforços de implementação. A literatura aponta para as consequências decorrentes da adoção das IFRS, mas é silente quanto ao processo prático de adoção, principalmente com a associação da utilização de métodos ágeis, que são um conjunto de práticas eficazes que se destinam a permitir entregas rápidas e com alta qualidade, tendo uma abordagem de negócios que alinha o desenvolvimento do projeto com as necessidades do cliente e os objetivos da empresa. A pesquisa contemplou a adoção da norma IFRS 16 pela Petrobras com a utilização do método Scrum, em que foram entrevistados os membros da equipe do projeto de adoção. O estudo demonstrou que os métodos ágeis podem ser aplicáveis ao processo de adoção de normas contábeis, havendo aceitação e entendimento dos pressupostos dos métodos ágeis por parte dos participantes do projeto. Assim, foi possível concluir que a utilização dos métodos ágeis pela Petrobras para a adoção da IFRS 16 foi adequada, abrindo caminhos para que esse tipo de metodologia venha a facilitar o processo de adoção de novas normas a serem emitidos pelos órgãos reguladores. As implicações consistem em consignar na literatura contábil a utilização dos métodos ágeis no processo de adoção de normas contábeis, não somente em grandes empresas, mas também nas médias e pequenas, nos escritórios de contabilidade, consultoria e na academia.
Involvement of PAR2 in inflammatory mediator release from human blood eosinophils
Authors: Hu Xinyu , Wang Haoyang
Published: July 2023

Proteinase Activated Receptors (PARs) are the members of G-protein-coupled receptor family and can be cleaved by certain serine proteases to expose a tethered ligand domain, which binds and activates the receptors to initiate multiple signaling cascades. There is some evidence that certain proteases may regulate target cells by activating PARs. There are many studies, in which PARs play important roles in inflammation. One study indicated that PAR2 inhibition and deletion significantly suppressed the degree of inflammation due to decreased IL-6 and IL-1 levels. Another study also showed that PARs activation could mediate reactive oxygen species production and MAPK signaling leading to alveolar inflammation. In addition, platelet-derived CAPN1 can trigger the vascular inflammation associated with diabetes via cleavage of PAR1 and the release of TNF from the endothelial cell surface, and sarsasapogenin may alleviate diabetic nephropathy by the downregulation of PAR1. Another Phellodendron amurense bark extract can suppress the particulate matter-induced Ca2+ influx caused by direct action upon PAR2, alleviating inflammation and maintaining homeostatic levels of cell adhesion components. There are also other two antagonists of I-287 and GB88, which can reduce the PAR2-mediated inflammatory reaction. In this study, we tested expression of PARs and IL-5, IL-6, RANTES and ECP release from human blood eosinophils using different enzymes and PAR agonists. The expression of PARs was assessed in human blood eosinophils by flow cytometry and RT-PCR, and the levels of cytokine and eosinophil cationic protein (ECP) in the cultured supernatants were determined with ELISA kits. Flow cytometry shows that human eosinophils express PAR2 protein and do not express PAR1, PAR3 and PAR4 proteins. RT-PCR analysis revealed expression of PAR2 and PAR3 genes in human eosinophils. Tryptase, trypsin and elastase can induce significant IL-5, IL-6 and ECP release. Trypsin and elastase may also stimulate RANTES secretion, but tryptase cannot induce the RANTES secretion. Tryptase, trypsin and elastase-induced cytokine and ECP release from human blood eosinophils most likely occurs via activation of PAR2.