scholarly journals The relationship between sternum variation and mode of locomotion in birds

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Talia M. Lowi-Merri ◽  
Roger B. J. Benson ◽  
Santiago Claramunt ◽  
David C. Evans
Keyword(s):  
Body Shape ◽  
Explanatory Power ◽  
Critical Element ◽  
Form And Function ◽  
Avian Flight ◽  
Flight Muscles ◽  
Ecological Importance ◽  
And Function ◽  
Future Work ◽  
The Relationship

Abstract Background The origin of powered avian flight was a locomotor innovation that expanded the ecological potential of maniraptoran dinosaurs, leading to remarkable variation in modern birds (Neornithes). The avian sternum is the anchor for the major flight muscles and, despite varying widely in morphology, has not been extensively studied from evolutionary or functional perspectives. We quantify sternal variation across a broad phylogenetic scope of birds using 3D geometric morphometrics methods. Using this comprehensive dataset, we apply phylogenetically informed regression approaches to test hypotheses of sternum size allometry and the correlation of sternal shape with both size and locomotory capabilities, including flightlessness and the highly varying flight and swimming styles of Neornithes. Results We find evidence for isometry of sternal size relative to body mass and document significant allometry of sternal shape alongside important correlations with locomotory capability, reflecting the effects of both body shape and musculoskeletal variation. Among these, we show that a large sternum with a deep or cranially projected sternal keel is necessary for powered flight in modern birds, that deeper sternal keels are correlated with slower but stronger flight, robust caudal sternal borders are associated with faster flapping styles, and that narrower sterna are associated with running abilities. Correlations between shape and locomotion are significant but show weak explanatory power, indicating that although sternal shape is broadly associated with locomotory ecology, other unexplored factors are also important. Conclusions These results display the ecological importance of the avian sternum for flight and locomotion by providing a novel understanding of sternum form and function in Neornithes. Our study lays the groundwork for estimating the locomotory abilities of paravian dinosaurs, the ancestors to Neornithes, by highlighting the importance of this critical element for avian flight, and will be useful for future work on the origin of flight along the dinosaur-bird lineage.

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

scholarly journals Form and function in hillslope hydrology: characterization of subsurface flow based on response observations

2017 ◽  
Vol 21 (7) ◽  
pp. 3727-3748 ◽  
Author(s):  
Lisa Angermann ◽  
Conrad Jackisch ◽  
Niklas Allroggen ◽  
Matthias Sprenger ◽  
Erwin Zehe ◽  
...  
Keyword(s):  
Preferential Flow ◽  
Explanatory Power ◽  
Subsurface Flow ◽  
Time Lapse ◽  
Storm Event ◽  
Monitoring Methods ◽  
Catchment Scale ◽  
Flow Paths ◽  
Form And Function ◽  
And Function

Abstract. The phrase form and function was established in architecture and biology and refers to the idea that form and functionality are closely correlated, influence each other, and co-evolve. We suggest transferring this idea to hydrological systems to separate and analyze their two main characteristics: their form, which is equivalent to the spatial structure and static properties, and their function, equivalent to internal responses and hydrological behavior. While this approach is not particularly new to hydrological field research, we want to employ this concept to explicitly pursue the question of what information is most advantageous to understand a hydrological system. We applied this concept to subsurface flow within a hillslope, with a methodological focus on function: we conducted observations during a natural storm event and followed this with a hillslope-scale irrigation experiment. The results are used to infer hydrological processes of the monitored system. Based on these findings, the explanatory power and conclusiveness of the data are discussed. The measurements included basic hydrological monitoring methods, like piezometers, soil moisture, and discharge measurements. These were accompanied by isotope sampling and a novel application of 2-D time-lapse GPR (ground-penetrating radar). The main finding regarding the processes in the hillslope was that preferential flow paths were established quickly, despite unsaturated conditions. These flow paths also caused a detectable signal in the catchment response following a natural rainfall event, showing that these processes are relevant also at the catchment scale. Thus, we conclude that response observations (dynamics and patterns, i.e., indicators of function) were well suited to describing processes at the observational scale. Especially the use of 2-D time-lapse GPR measurements, providing detailed subsurface response patterns, as well as the combination of stream-centered and hillslope-centered approaches, allowed us to link processes and put them in a larger context. Transfer to other scales beyond observational scale and generalizations, however, rely on the knowledge of structures (form) and remain speculative. The complementary approach with a methodological focus on form (i.e., structure exploration) is presented and discussed in the companion paper by Jackisch et al.(2017).

Relationship of Skeletal Muscle Atrophy to Functional Status: A Systematic Research Review

2000 ◽  
Vol 2 (2) ◽  
pp. 117-131 ◽  
Author(s):  
Kathleen Michael
Keyword(s):  
Muscle Atrophy ◽  
Elderly Women ◽  
Functional Limitation ◽  
Skeletal Muscle Atrophy ◽  
Research Review ◽  
Systematic Research ◽  
Form And Function ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

In the realm of muscle atrophy research, many studies address minute details of molecular function but few examine the effects of atrophy in terms of mobility, strength, endurance, and performance of activities of daily living. The relationship between impairment and functional limitation is the focus of this research review. A wide array of studies constitute this area of inquiry, including investigations as diverse and widely disparate as molecular chemistry and space travel and populations as different as rats, healthy young men, and elderly women. Thirty-four studies were selected based on their fit with the Enabling-Disabling Model. Three paradigms of atrophy and function emerged. Adaptation reflects the plastic nature of muscle when placed under certain conditions, ranging from disuse to high-resistance exercise. Injury/loss describes damage to muscle tissue from ischemia, medications, or reloading or reperfusion trauma. Also in this category is the loss of muscle that is seen with aging. Integrity relates to the muscle’s tendency to protect itself and maintain structural adjacencies and cellular proportions. Based on the 3 muscle research paradigms, the relationship of muscle atrophy to function is portrayed as a bidirectional interaction wherein form and function have an influence on each other by way of physical changes, including those of adaptation, injury/loss, or integrity. A conceptual model is constructed to reflect this relationship.

scholarly journals Identification and characterization of two types of amino acid-regulated acetyltransferases in actinobacteria

2017 ◽  
Vol 37 (4) ◽  
Author(s):  
Yu-Xing Lu ◽  
Xin-Xin Liu ◽  
Wei-Bing Liu ◽  
Bang-Ce Ye
Keyword(s):  
Amino Acid ◽  
Feedback Regulation ◽  
Protein Acetylation ◽  
Post Translational Modifications ◽  
Act Domain ◽  
Amino Acid Binding ◽  
Amino Acid Sensing ◽  
And Function ◽  
Future Work ◽  
The Relationship

Abstract One hundred and fifty GCN5-like acetyltransferases with amino acid-binding (ACT)-GCN5-related N-acetyltransferase (GNAT) domain organization have been identified in actinobacteria. The ACT domain is fused to the GNAT domain, conferring amino acid-induced allosteric regulation to these protein acetyltransferases (Pat) (amino acid sensing acetyltransferase, (AAPatA)). Members of the AAPatA family share similar secondary structure and are divided into two groups based on the allosteric ligands of the ACT domain: the asparagine (Asn)-activated PatA and the cysteine (Cys)-activated PatA. The former are mainly found in Streptomyces; the latter are distributed in other actinobacteria. We investigated the effect of Asn and Cys on the acetylation activity of Sven_0867 (SvePatA, from Streptomyces venezuelae DSM 40230) and Amir_5672 (AmiPatA, from Actinosynnema mirum strain DSM 43827), respectively, as well as the relationship between the structure and function of these enzymes. These findings indicate that the activity of PatA and acetylation level of proteins may be closely correlated with intracellular concentrations of Asn and Cys in actinobacteria. Amino acid-sensing signal transduction in acetyltransferases may be a mechanism that regulates protein acetylation in response to nutrient availability. Future work examining the relationship between protein acetylation and amino acid metabolism will broaden our understanding of post-translational modifications (PTMs) in feedback regulation.

Verb inflection in Ancient Greek and Sanskrit and auxiliation patterns in French and Italian

2009 ◽  
Vol 32 (1) ◽  
pp. 55-76 ◽  
Author(s):  
Nunzio La Fauci ◽  
Liana Tronci
Keyword(s):  
Complex Interaction ◽  
Ancient Greek ◽  
Form And Function ◽  
European Languages ◽  
Verb Inflection ◽  
The Subject ◽  
The Difference ◽  
Verb Inflections ◽  
And Function ◽  
The Relationship

This paper deals with the complex interaction between form and function in the verb morphosyntax of four Indo-European languages (French, Italian, Ancient Greek and Sanskrit). Beyond the difference in form, auxiliation patterns in French and Italian, and verb inflections in Ancient Greek and Sanskrit correlate, thanks to the agreement for number and person, to the expression of the relationship with the Subject. The different auxiliation patterns (sum and habeo) and the different inflections (middle and active) correlate to different properties of the Subject. In particular, these forms depend on the syntactic opposition between middle and non-middle. The ways of this dependency are regulated and systematic, although they appear fuzzy and chaotic, not only if the four languages are compared to each other, but also if different morphosyntactic combinations, inside the same language, are concerned.

Towards a pragmatic approach to the study of languages in contact

Pragmatics ◽  
1991 ◽  
Vol 1 (4) ◽  
pp. 465-480 ◽  
Author(s):  
Joan A. Argente ◽  
Lluís Payrató
Keyword(s):  
Language Contact ◽  
Communicative Competence ◽  
Form And Function ◽  
Languages In Contact ◽  
The Social ◽  
Interactive Strategies ◽  
And Function ◽  
Adaptation Processes ◽  
The Relationship ◽  
New Distribution

The study of language contact has been traditionally carried out from a structural perspective (synchronic or diachronic), from a sociolinguistic perspective and/or from a rather psychological perspective, centered on the linguistic and communicative competence of the multilingual individual. However, a great number of linguistic and sociolinguistic topics that appear in language contact situations may be productively tackled from a pragmatic viewpoint. This pragmatic perspective takes into account linguistic use in communication contexts and raises, at a different level, questions that deal with the structures and the evolution of the codes in contact. The main aim of this presentation is the analysis of some of the specific problems that arise in given language contact situations from a pragmatic perspective, considering the adaptation processes of the speakers, their particular interactive strategies and the social meaning generated. Understanding pragmatics in its original sense, i.e. as the study of the relationship between linguistic signs and speakers (users of certain resources), these phenomena should be understood as the result of speakers’ adaptation to changing sociocultural circumstances. This adaptation creates a new distribution of the verbal resources (or linguistic economy) of the community and, consequently, modifies its varieties as far as form and function are concerned.

English as a Lingua Franca: form follows function

English Today ◽  
2008 ◽  
Vol 24 (3) ◽  
pp. 58-61 ◽  
Author(s):  
Alessia Cogo
Keyword(s):  
Research Field ◽  
World Englishes ◽  
Lingua Franca ◽  
Form And Function ◽  
The World ◽  
And Function ◽  
The Relationship

ABSTRACTIn this paper I wish to respond to the article published in ET94 by Saraceni while at the same time providing some clarifications concerning the concept of English as a Lingua Franca (henceforth ELF). In his article Saraceni raises three main questions (and a number of related debatable comments which I will quickly deal with in my final remarks) regarding: 1) the nature of ELF and its speakers, 2) the relationship between ELF and the World Englishes (henceforth WE) paradigm, and 3) the distinction between form and function. I will address each of these questions, and in so doing consider a number of notions concerning the ELF research field.

scholarly journals Examining Form and Function of Dendritic Spines

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kevin F. H. Lee ◽  
Cary Soares ◽  
Jean-Claude Béïque
Keyword(s):  
Dendritic Spines ◽  
Laser Scanning ◽  
Molecular Mechanisms ◽  
Laser Scanning Microscopy ◽  
Spine Morphology ◽  
Functional Changes ◽  
Form And Function ◽  
Spine Structure ◽  
And Function ◽  
The Relationship

The majority of fast excitatory synaptic transmission in the central nervous system takes place at protrusions along dendrites called spines. Dendritic spines are highly heterogeneous, both morphologically and functionally. Not surprisingly, there has been much speculation and debate on the relationship between spine structure and function. The advent of multi-photon laser-scanning microscopy has greatly improved our ability to investigate the dynamic interplay between spine form and function. Regulated structural changes occur at spines undergoing plasticity, offering a mechanism to account for the well-described correlation between spine size and synapse strength. In turn, spine structure can influence the degree of biochemical and perhaps electrical compartmentalization at individual synapses. Here, we review the relationship between dendritic spine morphology, features of spine compartmentalization and synaptic plasticity. We highlight emerging molecular mechanisms that link structural and functional changes in spines during plasticity, and also consider circumstances that underscore some divergence from a tight structure-function coupling. Because of the intricate influence of spine structure on biochemical and electrical signalling, activity-dependent changes in spine morphology alone may thus contribute to the metaplastic potential of synapses. This possibility asserts a role for structural dynamics in neuronal information storage and aligns well with current computational models.

scholarly journals Material approaches to exploring the borders of paratext

2019 ◽  
Vol 11 (1-2) ◽  
pp. 106-129
Author(s):  
Sirkku Inkeri Ruokkeinen ◽  
Aino Liira
Keyword(s):  
Early Modern ◽  
Book History ◽  
Form And Function ◽  
Gray Area ◽  
Theoretical Approaches ◽  
Starting Point ◽  
Good Starting Point ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

This article examines the relationship of material text (text of the document) and paratext in light of fourteenth to sixteenth century evidence. Despite the wealth of interest generated by paratexts and paratextuality in recent years, especially in the fields of literary studies, book history, and translation studies, theoretical approaches to paratexts and paratextuality remain scarce. The paratextual status of an element is typically determined by its function, in combination with its distance from the material text: elements within the codex which do not share space with the text are part of the paratext. Less studied, however, is the gray area of elements which are located within the codex and share the space with the text. We examine this border between text and paratext through an analysis of late medieval and early modern initials, typeface, script and notes. While the form and function of the element are a good starting point, we propose that gauging the optionality of the element, in relation to the abstract text of the work and the material text of the document, is a better indicator of its paratextual status. Optionality should therefore be taken into consideration as evidence of a type of contemporary paratextual understanding.

Sign in / Sign up

Export Citation Format

Share Document