scholarly journals Pharyngeal Jaws Converge by Similar Means, Not to Similar Ends, When Minnows (Cypriniformes: Leuciscidae) Adapt to New Dietary Niches

2019 ◽  
Vol 59 (2) ◽  
pp. 432-442 ◽  
Author(s):  
Kelsie M Pos ◽  
Stacy C Farina ◽  
Matthew A Kolmann ◽  
Nicholas J Gidmark
Keyword(s):  
North American ◽  
Structural Changes ◽  
Phylogenetic Signal ◽  
Morphological Integration ◽  
Micro Computed Tomography ◽  
Muscle Attachment ◽  
Opposite Pattern ◽  
Trade Off ◽  
Form Function ◽  
Pharyngeal Jaws

Abstract Convergent evolution is at the forefront of many form-function studies. There are many examples of multiple independent lineages evolving a similar morphology in response to similar functional demands, providing a framework for testing hypotheses of form-function evolution. However, there are numerous clades with underappreciated convergence, in which there is a perceived homogeneity in morphology. In these groups, it can be difficult to investigate causal relationships of form and function (e.g., diet influencing the evolution of jaw morphology) without the ability to disentangle phylogenetic signal from convergence. Leuciscids (Cypriniformes: Leuciscidae; formerly nested within Cyprinidae) are a species-rich clade of fishes that have diversified to occupy nearly every freshwater trophic niche, yet are considered to have relatively low morphological diversity relative to other large freshwater clades. Within the North American leuciscids, many genera contain at least one herbivore, insectivore, and larvaphage. We created 3D models from micro-computed tomography scans of 165 leuciscid species to measure functionally relevant traits within the pharyngeal jaws of these fishes. Using a published phylogeny, we tested these metrics for evolutionary integration, phylogenetic signal, and correlation with diet. Measurements of the pharyngeal jaws, muscle attachment areas, and teeth showed strong positive evolutionary correlation with each other and negative evolutionary correlation with measurements of the inter-ceratobranchial ligament (ICB ligament). Using diet data from published literature, we found extensive dietary convergence within Leuciscidae. The most common transitions we found were between herbivorous and invertivorous taxa and between insectivore types (aquatic vs. terrestrial). We document a trade-off in which herbivorous leuciscids have large teeth, short ICB ligaments, and large muscle attachment areas, whereas insectivorous leuciscids showed the opposite pattern. Inverse patterns of morphological integration between the ICB ligament the rest of the pharyngeal jaw correspond this dietary trade-off, which indicates that coordinated evolution of morphological traits contributes to functional diversity in this clade. However, these patterns only emerge in the context of phylogeny, meaning that the pharyngeal jaws of North American leuciscids converge by similar means (structural changes in response to dietary demands), but not necessarily to similar ends (absolute phenotype).

Characterization of Human Cortical and Trabecular Bone Structural Change by NMR and Micro-CT

2012 ◽  
Author(s):  
Qingwen Ni ◽  
Todd Bredbenner
Keyword(s):  
Trabecular Bone ◽  
Spin Relaxation ◽  
Structural Changes ◽  
Relaxation Times ◽  
Proton Nuclear Magnetic Resonance ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
T2 Relaxation ◽  
Ct Measurement

The techniques of low-field pulsed proton nuclear magnetic resonance (NMR) spin relaxation and Micro-CT are described for assessment of structural changes of human cortical and trabecular bone in vitro. The technique involves spin-spin relaxation measurement and inversion spin-spin spectral analysis methods for NMR. From NMR measurement, the CPMG T2 relaxation data can be inverted to T2 relaxation distribution and this distribution then can be transformed to a pore size distribution with the longer relaxation times corresponding to larger pores. In Micro-CT measurement, each trabecular bone specimen was individually scanned using a micro-computed tomography (micro-CT) system and 12 micron dimensionally-isotropic voxels were reconstructed. Due to the resolution limitation, Micro-CT measurement on cortical bone was not success, however, NMR measurement was success for both cortical and trabecular bones.

scholarly journals The Labour Relations Act and changes to the structure of bargaining

1970 ◽  
Vol 13 (2) ◽  
Author(s):  
Greg Wood
Keyword(s):  
Structural Changes ◽  
Real Wages ◽  
Trade Off ◽  
Labour Relations ◽  
Sharp Fall ◽  
The Impact

This article discusses the impact of inflationary expectations and outcomes on the 1987-88 wage round, the first under the Labour Relations Act 1987. It argues that any trade-off between moderate wage settlements and the retention of the Mtional award system for at least another year has worked to the advantage of unions because of the sharp fall in inflation since September 1987. Since real wages have in general at least been mainlained under negotiations which basically took place within the national award system, the pressures for major structural changes to the bargaining system are correspondingly less than if real wages had, as expected, declined.

scholarly journals Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1668 ◽  
Author(s):  
Tsung Fei Khang ◽  
Oi Yoon Michelle Soo ◽  
Wooi Boon Tan ◽  
Lee Hong Susan Lim
Keyword(s):  
Body Size ◽  
Phylogenetic Signal ◽  
R Package ◽  
Copulatory Organ ◽  
Morphological Integration ◽  
28S Rrna ◽  
Morphometric Data ◽  
Geometric Morphometric ◽  
Shape Data ◽  
Shape And Size

Background.Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions.Materials and Methods.We used data from anchor morphometry, body size and morphology of 13Ligophorus(Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts:Moolgarda buchanani(Bleeker) andLiza subviridis(Valenciennes) from Malaysia. Anchor shape and size data (n= 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams’sKmultwas used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data.Results.We discriminated 12 of the 13Ligophorusspecies using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root point, and the length between the inner root point and the dent point. The species onM. buchananievolved larger, more robust anchors; those onL. subviridisevolved smaller, more delicate anchors. Anchor shape and size were significantly correlated, suggesting constraints in anchor evolution. Tight integration between the root and the point compartments within anchors confirms the anchor as a single, fully integrated module. The correlation between male copulatory organ morphology and size with anchor shape was consistent with predictions from the Rohde-Hobbs hypothesis.Conclusions.Monogenean anchors are tightly integrated structures, and their shape variation correlates strongly with phylogeny, thus underscoring their value for systematic and evolutionary biology studies. Our MonogeneaGM R package provides tools for researchers to mine biological insights from geometric morphometric data of speciose monogenean genera.

Evaluation of cigarette smoke-induced emphysema in mice using quantitative micro-computed tomography

2015 ◽  
Vol 308 (10) ◽  
pp. L1039-L1045 ◽  
Author(s):  
Mamoru Sasaki ◽  
Shotaro Chubachi ◽  
Naofumi Kameyama ◽  
Minako Sato ◽  
Mizuha Haraguchi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cigarette Smoke ◽  
Structural Changes ◽  
Chronic Obstructive ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Obstructive Pulmonary Disease ◽  
Calculated Volume ◽  
Lung Ct ◽  
Time Point

Chronic cigarette smoke (CS) exposure provokes variable changes in the lungs, and emphysema is an important feature of chronic obstructive pulmonary disease. The usefulness of micro-computed tomography (CT) to assess emphysema in different mouse models has been investigated, but few studies evaluated the dynamic structural changes in a CS-induced emphysema mouse model. A novel micro-CT technique with respiratory and cardiac gating has resulted in high-quality images that enable processing for further quantitative and qualitative analyses. Adult female C57BL/6J mice were repeatedly exposed to mainstream CS, and micro-CT scans were performed at 0, 4, 12, and 20 wk. Emphysema was also histologically quantified at each time point. Air-exposed mice and mice treated with intratracheal elastase served as controls and comparisons, respectively. End-expiratory lung volume, corresponding to functional residual volume, was defined as the calculated volume at the phase of end-expiration, and it evaluated air trapping. The end-expiratory lung volumes of CS-exposed mice were significantly larger than those of air controls at 12 and 20 wk, which was in line with alveolar enlargement and destruction by histological quantification. However, CS exposure neither increased low attenuation volume nor decreased the average lung CT value at any time point, unlike the elastase-instilled emphysema model. CS-exposed mice had rather higher average lung CT values at 4 and 12 wk. This is the first study characterizing a CS-induced emphysema model on micro-CT over time in mice. Moreover, these findings extend our understanding of the distinct pathophysiology of CS-induced emphysema in mice.

scholarly journals Quantitative models of the rat pulmonary arterial tree morphometry applied to hypoxia-induced arterial remodeling

2004 ◽  
Vol 97 (6) ◽  
pp. 2372-2384 ◽  
Author(s):  
Robert C. Molthen ◽  
Kelly L. Karau ◽  
Christopher A. Dawson
Keyword(s):  
Structural Changes ◽  
Pulmonary Arteries ◽  
Cor Pulmonale ◽  
Arterial Remodeling ◽  
Sprague Dawley ◽  
Micro Computed Tomography ◽  
Arterial Tree ◽  
Arterial Structure ◽  
Pulmonary Arterial ◽  
Isolated Lungs

Little is known about the constituent hemodynamic consequences of structural changes that occur in the pulmonary arteries during the onset and progression of pulmonary arterial remodeling. Many disease processes are known to be responsible for vascular remodeling that leads to pulmonary arterial hypertension, cor pulmonale, and death. Histology has been the primary tool for evaluating pulmonary remodeling, but it does not provide information on intact vascular structure or the vessel mechanical properties. This study is an extension of our previous work in which we developed an alternative imaging technique to evaluate pulmonary arterial structure. The lungs from Sprague-Dawley rats were removed, perfusion analysis was performed on the isolated lungs, and then an X-ray contrast agent was used to fill the arterial network for imaging. The lungs were scanned over a range of intravascular pressures by volumetric micro-computed tomography, and the arterial morphometry was mapped and measured in the reconstructed isotropic volumes. A quantitative assessment of hemodynamic, structural, and biomechanical differences between rats exposed for 21 days to hypoxia (10% O2) or normoxia (21.0% O2) was performed. One metric, the normalized distensibility of the arteries, is significantly ( P < 0.001) larger [0.025 ± 0.0011 (SE) mmHg−1] ( n = 9) in normoxic rats compared with hypoxic [0.015 ± 0.00077 (SE) mmHg−1] ( n = 9). The results of the study show that these models can be applied to the Sprague-Dawley rat data and, specifically, can be used to differentiate between the hypoxic and the control groups.

A review of structural changes in North American consumption of softwood lumber: Past, present and future

1996 ◽  
Vol 72 (6) ◽  
pp. 631-636
Author(s):  
David H. Cohen
Keyword(s):  
United States ◽  
Key Words ◽  
North American ◽  
Structural Changes ◽  
The United States ◽  
Residential Construction ◽  
Information Analysis ◽  
Softwood Lumber ◽  
End Use ◽  
Use Categories

A study of end use of softwood lumber consumption in Canada and the United States indicated that there was little difference among existing published information. Analysis of methodology by publication indicates that published information is most likely accurate. End use categories consisted of the following four sectors in descending order of quantity consumed: residential construction, repair and remodeling, non-residential construction and other. Each area is discussed in terms of past, current and future use trends. In addition major trends in both how lumber is consumed and distributed are discussed briefly. Key words: lumber, consumption, distribution, repair and remodeling

scholarly journals Anatomy of the Nasal and Auditory Regions of the Fossil Lagomorph Palaeolagus haydeni: Systematic and Evolutionary Implications

2021 ◽  
Vol 9 ◽  
Author(s):  
Irina Ruf ◽  
Jin Meng ◽  
Łucja Fostowicz-Frelik
Keyword(s):  
Computed Tomography ◽  
Middle Ear ◽  
North American ◽  
Late Eocene ◽  
Early Miocene ◽  
Thin Wall ◽  
Micro Computed Tomography ◽  
3D Reconstructions ◽  
Early Oligocene ◽  
Ontogenetic Stages

Palaeolagus, a late Eocene to early Miocene North American lagomorph genus, represented by numerous and well-preserved specimens, has been long considered a basal leporid, although it is currently understood as a stem lagomorph. Based on micro-computed tomography (μCT) data and 3D reconstructions, here we present the first description of intracranial structures of the nasal and auditory regions of a complete skull of Palaeolagus haydeni from the early Oligocene of Nebraska. Although Palaeolagus haydeni shows a puzzling mixture of extant leporid and ochotonid characters, it helps to polarize and re-evaluate already known lagomorph intracranial characters based on outgroup comparison with Rodentia and Scandentia. Common derived features of Palaeolagus haydeni and extant Lagomorpha are the dendritic maxilloturbinal and the excavated nasoturbinal that contacts the lamina semicircularis. Generally, Palaeolagus haydeni and Leporidae have several characters in common, some of which are certainly plesiomorphic (e.g., thin wall of bulla tympani and flat conic cochlea). Palaeolagus haydeni resembles Leporidae in having an interturbinal between the two frontoturbinals, and three ethmoturbinals plus one interturbinal between ethmoturbinal I and II. Now, this should also be regarded as a plesiomorphic grundplan pattern for Leporidae whereas ochotonids are derived from the lagomorph grundplan as concerns the number of frontoturbinals. Concerning the middle ear, Palaeolagus haydeni significantly contributes to the polarization of the anterior anchoring of the malleus in extant lagomorphs. Palaeolagus haydeni resembles the pattern observed in early ontogenetic stages of Ochotonidae, i.e., the attachment of the malleus to the ectotympanic via a short processus anterior. The patterns in adult ochotonids and leporids now can be regarded as two different and apomorphic character states. Autapomorphic characters of Palaeolagus haydeni are the reduced frontoturbinal 2 and the additional anterolaterally oriented process of the lamina semicircularis. Interestingly, among the investigated intracranial structures the loss of the secondary crus commune is the only apomorphic grundplan character of crown Lagomorpha.

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