scholarly journals Multiple Functional Solutions During Flightless to Flight-Capable Transitions

2021 ◽  
Vol 8 ◽  
Author(s):  
Ashley M. Heers ◽  
Stephanie L. Varghese ◽  
Leila K. Hatier ◽  
Jeremiah J. Cabrera

The evolution of avian flight is one of the great transformations in vertebrate history, marked by striking anatomical changes that presumably help meet the demands of aerial locomotion. These changes did not occur simultaneously, and are challenging to decipher. Although extinct theropods are most often compared to adult birds, studies show that developing birds can uniquely address certain challenges and provide powerful insights into the evolution of avian flight: unlike adults, immature birds have rudimentary, somewhat “dinosaur-like” flight apparatuses and can reveal relationships between form, function, performance, and behavior during flightless to flight-capable transitions. Here, we focus on the musculoskeletal apparatus and use CT scans coupled with a three-dimensional musculoskeletal modeling approach to analyze how ontogenetic changes in skeletal anatomy influence muscle size, leverage, orientation, and corresponding function during the development of flight in a precocial ground bird (Alectoris chukar). Our results demonstrate that immature and adult birds use different functional solutions to execute similar locomotor behaviors: in spite of dramatic changes in skeletal morphology, muscle paths and subsequent functions are largely maintained through ontogeny, because shifts in one bone are offset by changes in others. These findings help provide a viable mechanism for how extinct winged theropods with rudimentary pectoral skeletons might have achieved bird-like behaviors before acquiring fully bird-like anatomies. These findings also emphasize the importance of a holistic, whole-body perspective, and the need for extant validation of extinct behaviors and performance. As empirical studies on locomotor ontogeny accumulate, it is becoming apparent that traditional, isolated interpretations of skeletal anatomy mask the reality that integrated whole systems function in frequently unexpected yet effective ways. Collaborative and integrative efforts that address this challenge will surely strengthen our exploration of life and its evolutionary history.

1998 ◽  
Vol 14 (2) ◽  
pp. 223-237 ◽  
Author(s):  
Bing Yu ◽  
James G. Andrews

The purpose of this study was to investigate relationships between free limb motions and triple jump performance. The subjects were 13 elite male triple jumpers. Three-dimensional videographic data were collected using a direct linear transformation technique with panning cameras. Changes in the velocity of the whole body center of gravity (G), changes in the whole body angular momentum about G, changes in the velocity of G due to free limb motions, and changes in the whole body angular momentum about G due to free limb motions were determined for each of the three support phases. Free limb motions were associated with decreases in the forward horizontal velocity of G and increases in the vertical velocity of G and significantly influenced changes of the corresponding velocity components of G when the changes were large. The free limb motions also created some angular momentum components about G during each support phase but did not significantly influence the changes of the corresponding angular momentum components of the whole body. Neither the changes in the three velocity components of G nor the changes in the three angular momentum components of the whole body about G due to free limb motions were significantly related to the actual distance of the triple jump.


2020 ◽  
pp. 1-12
Author(s):  
Wu Xin ◽  
Qiu Daping

The inheritance and innovation of ancient architecture decoration art is an important way for the development of the construction industry. The data process of traditional ancient architecture decoration art is relatively backward, which leads to the obvious distortion of the digitalization of ancient architecture decoration art. In order to improve the digital effect of ancient architecture decoration art, based on neural network, this paper combines the image features to construct a neural network-based ancient architecture decoration art data system model, and graphically expresses the static construction mode and dynamic construction process of the architecture group. Based on this, three-dimensional model reconstruction and scene simulation experiments of architecture groups are realized. In order to verify the performance effect of the system proposed in this paper, it is verified through simulation and performance testing, and data visualization is performed through statistical methods. The result of the study shows that the digitalization effect of the ancient architecture decoration art proposed in this paper is good.


2016 ◽  
pp. 81-106
Author(s):  
E. Borisova ◽  
A. Kulkova

Various components of culture have long been in the focus of economic research. Numerous empirical studies show that cultural norms, as well as religion and language, matter for economic development and have not only statistical but also economic significance. This paper considers various examples of how culture can affect individual values and behavior. It also deals with personal names as a key marker of one’s cultural identity. Overall, the paper contributes to the more profound understanding of a famous notion that "culture matters", and helps clarify the mechanisms through which culture exerts its influence.


2018 ◽  
Vol 13 (2) ◽  
pp. 187-211
Author(s):  
Patricia E. Chu

The Paris avant-garde milieu from which both Cirque Calder/Calder's Circus and Painlevé’s early films emerged was a cultural intersection of art and the twentieth-century life sciences. In turning to the style of current scientific journals, the Paris surrealists can be understood as engaging the (life) sciences not simply as a provider of normative categories of materiality to be dismissed, but as a companion in apprehending the “reality” of a world beneath the surface just as real as the one visible to the naked eye. I will focus in this essay on two modernist practices in new media in the context of the history of the life sciences: Jean Painlevé’s (1902–1989) science films and Alexander Calder's (1898–1976) work in three-dimensional moving art and performance—the Circus. In analyzing Painlevé’s work, I discuss it as exemplary of a moment when life sciences and avant-garde technical methods and philosophies created each other rather than being classified as separate categories of epistemological work. In moving from Painlevé’s films to Alexander Calder's Circus, Painlevé’s cinematography remains at the forefront; I use his film of one of Calder's performances of the Circus, a collaboration the men had taken two decades to complete. Painlevé’s depiction allows us to see the elements of Calder's work that mark it as akin to Painlevé’s own interest in a modern experimental organicism as central to the so-called machine-age. Calder's work can be understood as similarly developing an avant-garde practice along the line between the bestiary of the natural historian and the bestiary of the modern life scientist.


2015 ◽  
Vol 11 (1) ◽  
pp. 2897-2908
Author(s):  
Mohammed S.Aljohani

Tomography is a non-invasive, non-intrusive imaging technique allowing the visualization of phase dynamics in industrial and biological processes. This article reviews progress in Electrical Capacitance Volume Tomography (ECVT). ECVT is a direct 3D visualizing technique, unlike three-dimensional imaging, which is based on stacking 2D images to obtain an interpolated 3D image. ECVT has recently matured for real time, non-invasive 3-D monitoring of processes involving materials with strong contrast in dielectric permittivity. In this article, ECVT sensor design, optimization and performance of various sensors seen in literature are summarized. Qualitative Analysis of ECVT image reconstruction techniques has also been presented.


Author(s):  
Jie Gao ◽  
Chunde Tao ◽  
Dongchen Huo ◽  
Guojie Wang

Marine, industrial, turboprop and turboshaft gas turbine engines use nonaxisymmetric exhaust volutes for flow diffusion and pressure recovery. These processes result in a three-dimensional complex turbulent flow in the exhaust volute. The flows in the axial turbine and nonaxisymmetric exhaust volute are closely coupled and inherently unsteady, and they have a great influence on the turbine and exhaust aerodynamic characteristics. Therefore, it is very necessary to carry out research on coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics, so as to provide reference for the high-efficiency turbine-volute designs. This paper summarizes and analyzes the recent advances in the field of coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics for turbomachinery. This review covers the following topics that are important for turbine and volute coupled designs: (1) flow and loss characteristics of nonaxisymmetric exhaust volutes, (2) flow interactions between axial turbine and nonaxisymmetric exhaust volute, (3) improvement of turbine and volute performance within spatial limitations and (4) research methods of coupled turbine and exhaust volute aerodynamics. The emphasis is placed on the turbine-volute interactions and performance improvement. We also present our own insights regarding the current research trends and the prospects for future developments.


2021 ◽  
Vol 23 (7) ◽  
Author(s):  
Susanne Hörz-Sagstetter ◽  
Ludwig Ohse ◽  
Leonie Kampe

Abstract Purpose of Review The concept of personality functioning (Alternative DSM-5 Model of Personality Disorders) has led to increased interest in dimensional personality disorder diagnosis. While differing markedly from the current categorical classification, it is closely related to the psychodynamic concepts of personality structure and personality organization. In this review, the three dimensional approaches, their underlying models, and common instruments are introduced, and empirical studies on similarities and differences between the concepts and the categorical classification are summarized. Additionally, a case example illustrates the clinical application. Recent Findings Numerous studies demonstrate the broad empirical basis, validated assessment instruments and clinical usefulness of the dimensional concepts. Their advantages compared to the categorical approach, but also the respective differences, have been demonstrated empirically, in line with clinical observations. Summary Evidence supports the three dimensional concepts, which share conceptual overlap, but also entail unique aspects of personality pathology, respectively.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Timothy M. Kistner ◽  
Katherine D. Zink ◽  
Steven Worthington ◽  
Daniel E. Lieberman

AbstractTo test the effects of domestication on craniofacial skeletal morphology, we used three-dimensional geometric morphometrics (GM) along with linear and endocranial measurements to compare selected (domesticated) and unselected foxes from the Russian Farm-Fox Experiment to wild foxes from the progenitor population from which the farmed foxes are derived. Contrary to previous findings, we find that domesticated and unselected foxes show minimal differences in craniofacial shape and size compared to the more substantial differences between the wild foxes and both populations of farmed foxes. GM analyses and linear measurements demonstrate that wild foxes differ from farmed foxes largely in terms of less cranial base flexion, relatively expanded cranial vaults, and increased endocranial volumes. These results challenge the assumption that the unselected population of foxes kept as part of the Russian Farm-Fox experiment are an appropriate proxy for ‘wild’ foxes in terms of craniofacial morphology and highlight the need to include wild populations in further studies of domestication syndrome to disentangle the phenotypic effects of multiple selection pressures. These findings also suggest that marked increases in docility cannot be reliably diagnosed from shape differences in craniofacial skeletal morphology.


2020 ◽  
Vol 17 (163) ◽  
pp. 20190721
Author(s):  
J. Larsson ◽  
A. M. Westram ◽  
S. Bengmark ◽  
T. Lundh ◽  
R. K. Butlin

The growth of snail shells can be described by simple mathematical rules. Variation in a few parameters can explain much of the diversity of shell shapes seen in nature. However, empirical studies of gastropod shell shape variation typically use geometric morphometric approaches, which do not capture this growth pattern. We have developed a way to infer a set of developmentally descriptive shape parameters based on three-dimensional logarithmic helicospiral growth and using landmarks from two-dimensional shell images as input. We demonstrate the utility of this approach, and compare it to the geometric morphometric approach, using a large set of Littorina saxatilis shells in which locally adapted populations differ in shape. Our method can be modified easily to make it applicable to a wide range of shell forms, which would allow for investigations of the similarities and differences between and within many different species of gastropods.


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