scholarly journals Enhanced macroboring and depressed calcification drive net dissolution at high-CO 2 coral reefs

2016 ◽  
Vol 283 (1842) ◽  
pp. 20161742 ◽  
Author(s):  
Ian C. Enochs ◽  
Derek P. Manzello ◽  
Graham Kolodziej ◽  
Sam H. C. Noonan ◽  
Lauren Valentino ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Skeletal Structure ◽  
Global Ocean ◽  
Biological Processes ◽  
Micro Computed Tomography ◽  
Dead Coral ◽  
Intergovernmental Panel ◽  
Three Dimensional Models ◽  
First Time ◽  
High Carbon Dioxide

Ocean acidification (OA) impacts the physiology of diverse marine taxa; among them corals that create complex reef framework structures. Biological processes operating on coral reef frameworks remain largely unknown from naturally high-carbon-dioxide (CO 2 ) ecosystems. For the first time, we independently quantified the response of multiple functional groups instrumental in the construction and erosion of these frameworks (accretion, macroboring, microboring, and grazing) along natural OA gradients. We deployed blocks of dead coral skeleton for roughly 2 years at two reefs in Papua New Guinea, each experiencing volcanically enriched CO 2 , and employed high-resolution micro-computed tomography (micro-CT) to create three-dimensional models of changing skeletal structure. OA conditions were correlated with decreased calcification and increased macroboring, primarily by annelids, representing a group of bioeroders not previously known to respond to OA. Incubation of these blocks, using the alkalinity anomaly methodology, revealed a switch from net calcification to net dissolution at a pH of roughly 7.8, within Intergovernmental Panel on Climate Change's (IPCC) predictions for global ocean waters by the end of the century. Together these data represent the first comprehensive experimental study of bioerosion and calcification from a naturally high-CO 2 reef ecosystem, where the processes of accelerated erosion and depressed calcification have combined to alter the permanence of this essential framework habitat.

scholarly journals Active Cloaking and Illusion of Electric Potentials in Electrostatics

2021 ◽  
Author(s):  
Andreas Helfrich-Schkabarenko ◽  
Alik Ismail-Zadeh ◽  
Aron Sommer
Keyword(s):  
Electric Potential ◽  
Superposition Principle ◽  
Current Source ◽  
Three Dimensional ◽  
Numerical Results ◽  
Research Fields ◽  
Electric Potentials ◽  
Three Dimensional Models ◽  
First Time ◽  
A Current

Abstract Cloaking and illusion has been demonstrated theoretically and experimentally in several research fields. Here we present for the first time an active exterior cloaking device in electrostatics operating in a two-horizontally-layered electroconductive domain, and use the superposition principle to cloak electric potentials. The device uses an additional current source pattern introduced on the interface between two layers to cancel the total electric potential to be measured. Also, we present an active exterior illusion device allowing for detection of a signal pattern corresponding to any arbitrarily chosen current source instead of the existing current source. The performance of the cloaking/illusion devices is demonstrated by three-dimensional models and numerical experiments using synthetic measurements of the electric potential. Sensitivities of numerical results to a noise in measured data and to a size of cloaking devices are analysed. The numerical results show quite reasonable cloaking/illusion performance, which means that a current source can be hidden electrostatically. The developed active cloaking/illusion methodology can be used in subsurface geo-exploration studies, electrical engineering, live sciences, and elsewhere.

Morphology of the cephalothorax integument of Bryocamptus pygmaeus (Copepoda: Harpacticoida: Canthocamptidae), based on a new research method

2021 ◽  
Vol 30 (2) ◽  
pp. 320-330
Author(s):  
A.A. Novikov ◽  
E.B. Fefilova
Keyword(s):  
Three Dimensional ◽  
Komi Republic ◽  
Southeastern Part ◽  
The North ◽  
Udmurt Republic ◽  
The Republic ◽  
A New Technique ◽  
Three Dimensional Models ◽  
New Research ◽  
First Time

The number and location of sensilla and pores of the cephalothorax integument of the species Bryocamptus pygmaeus (G.O. Sars, 1863) (Copepoda, Canthocamptidae) were studied for the first time on the material from several European regions: the southeastern part of the Bolshezemelskaya tundra (Ne­nets Autonomous District), the north of the Komi Republic, the Republic of Karelia, and the central part of European Russia (Udmurt Republic). In the samples examined, two groups of populations differing in the characters of cephalothorax integument were recognised. These differences were found to correlate with the variability of the endopod of fourth pair of female legs, which bears four setae in specimens of the eastern form, while a specimen examined from Karelia has five setae. Pore maps are composed for both groups of morphotypes. A statistical analysis was carried out based on a new technique using three-dimensional models of the cephalothorax. As a result of this analysis, a high similarity between individuals of the eastern form and differences of the latter from the Karelian specimen were revealed.

scholarly journals An advanced shape-fitting algorithm applied to quadrupedal mammals: improving volumetric mass estimates

2015 ◽  
Vol 2 (8) ◽  
pp. 150302 ◽  
Author(s):  
Charlotte A. Brassey ◽  
James D. Gardiner
Keyword(s):  
Body Mass ◽  
Three Dimensional ◽  
Physical Property ◽  
Skeletal Structure ◽  
Shape Fitting ◽  
Alpha Shapes ◽  
Fundamental Physical Property ◽  
Three Dimensional Models ◽  
The Individual ◽  
Ground Sloth

Body mass is a fundamental physical property of an individual and has enormous bearing upon ecology and physiology. Generating reliable estimates for body mass is therefore a necessary step in many palaeontological studies. Whilst early reconstructions of mass in extinct species relied upon isolated skeletal elements, volumetric techniques are increasingly applied to fossils when skeletal completeness allows. We apply a new ‘alpha shapes’ ( α -shapes) algorithm to volumetric mass estimation in quadrupedal mammals. α -shapes are defined by: (i) the underlying skeletal structure to which they are fitted; and (ii) the value α , determining the refinement of fit. For a given skeleton, a range of α -shapes may be fitted around the individual, spanning from very coarse to very fine. We fit α -shapes to three-dimensional models of extant mammals and calculate volumes, which are regressed against mass to generate predictive equations. Our optimal model is characterized by a high correlation coefficient and mean square error ( r 2 =0.975, m.s.e.=0.025). When applied to the woolly mammoth ( Mammuthus primigenius ) and giant ground sloth ( Megatherium americanum ), we reconstruct masses of 3635 and 3706 kg, respectively. We consider α -shapes an improvement upon previous techniques as resulting volumes are less sensitive to uncertainties in skeletal reconstructions, and do not require manual separation of body segments from skeletons.

scholarly journals Accuracy and Reliability of Measurements Obtained from 3-Dimensional Rabbit Mandible Model: A Micro-Computed Tomography Study

2019 ◽  
Vol 69 (2) ◽  
pp. 192-200
Author(s):  
Orkun Akgün Remzi ◽  
Bakıcı Caner ◽  
Ekim Okan ◽  
Kaya Ufuk ◽  
Özlem Küçük Nuriye
Keyword(s):  
Three Dimensional ◽  
Third Molar ◽  
Calculated Data ◽  
Mental Foramen ◽  
Micro Computed Tomography ◽  
Morphometric Measurements ◽  
Biometric Data ◽  
3 Dimensional ◽  
Dimensional Models ◽  
Three Dimensional Models

Abstract The aim of this study was to evaluate the mandibular morphometric measurements of male and female rabbits using three-dimensional digital model and real bone measurements. Ten (5 female, 5 male) rabbits with no bone deformities were used in the study. Three-dimensional models were produced from two-dimensional microcomputed tomography images of the rabbit’s mandible. Biometric data were obtained by using the same measuring points over both three-dimensional models and real bone samples. There was only a significant main effect of gender for the greatest length of the mandible, length from aboral border of the alveolus of third molar teeth to infradentale, length of the diastema, height of the vertical ramus (measured in projection), distance from the incisor to the oral border of mental foramen, distance from aboral border of mental foramen to caudal border of mandible, distance between retroalveolar foramen and caudal border of mandible. For these measurements, calculated data for females are significantly higher than the males (p<0.05). It was found to be statistically significant between methods only for the length of the cheek tooth row and height of the vertical ramus values (p<0.05). In this study, it was understood that 3D morphometric measurements for bone tissue could be used with accuracy and reliability especially in anatomy and orthodontics areas as an alternative to traditional measurements made with a digital caliper.

scholarly journals A bird-like skull in a Triassic diapsid reptile increases heterogeneity of the morphological and phylogenetic radiation of Diapsida

2017 ◽  
Vol 4 (10) ◽  
pp. 170499 ◽  
Author(s):  
Adam C. Pritchard ◽  
Sterling J. Nesbitt
Keyword(s):  
Three Dimensional ◽  
Total Body Length ◽  
Phylogenetic Position ◽  
Micro Computed Tomography ◽  
Crown Group ◽  
Chinle Formation ◽  
Total Body ◽  
Permian Mass Extinction ◽  
First Time ◽  
A New Species

The Triassic Period saw the first appearance of numerous amniote lineages (e.g. Lepidosauria, Archosauria, Mammalia) that defined Mesozoic ecosystems following the end Permian Mass Extinction, as well as the first major morphological diversification of crown-group reptiles. Unfortunately, much of our understanding of this event comes from the record of large-bodied reptiles (total body length > 1 m). Here we present a new species of drepanosaurid (small-bodied, chameleon-like diapsids) from the Upper Triassic Chinle Formation of New Mexico. Using reconstructions of micro-computed tomography data, we reveal the three-dimensional skull osteology of this clade for the first time. The skull presents many archaic anatomical traits unknown in Triassic crown-group reptiles (e.g. absence of bony support for the external ear), whereas other traits (e.g. toothless rostrum, anteriorly directed orbits, inflated endocranium) resemble derived avian theropods. A phylogenetic analysis of Permo-Triassic diapsids supports the hypothesis that drepanosaurs are an archaic lineage that originated in the Permian, far removed from crown-group Reptilia. The phylogenetic position of drepanosaurids indicates the presence of archaic Permian clades among Triassic small reptile assemblages and that morphological convergence produced a remarkably bird-like skull nearly 100 Myr before one is known to have emerged in Theropoda.

scholarly journals Application of the method of observing the natural impulse electromagnetic field of the Earth to trace watered faults on the example of Yeristovo quarry

2019 ◽  
Vol 109 ◽  
pp. 00128
Author(s):  
Kristina Zmiievska ◽  
Oleksandr Tubaltsev ◽  
Artur Zmiievskyi
Keyword(s):  
Electromagnetic Field ◽  
Reliable Method ◽  
Three Dimensional ◽  
Field Studies ◽  
Express Method ◽  
Tectonic Structure ◽  
The Earth ◽  
Three Dimensional Models ◽  
First Time ◽  
Natural Impulse

The article presents the results of applying the express method of observing the natural impulse electromagnetic field of the Earth to isolate flooded faults in areas adjacent to the Yeristovo quarry. The features of the geological and tectonic structure of the territory of the Yeristovo field are considered. According to the results of the field studies, for the first time, maps of the density of the natural impulse electromagnetic field of the Earth flux were constructed for this area, which made it possible to isolate and trace the positions of watering faults. In addition, to visualize the most difficult fragments of the structure of the plots, three-dimensional models were built. On the basis of the conducted research, it is possible to recommend the use of water catching wells using a reasonably economical and reliable method of observing the natural impulse electromagnetic field of the Earth. It is advisable to lay them in the zones of minimum values of the natural impulse electromagnetic field of the Earth, within the southern parts of the research sites. The use of advanced observations will avoid unproductive costs when drilling water-reducing wells.

scholarly journals Cranial osteology of the Early Cretaceous turtle Pleurosternon bullockii (Paracryptodira: Pleurosternidae)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9454 ◽  
Author(s):  
Serjoscha W. Evers ◽  
Yann Rollot ◽  
Walter G. Joyce
Keyword(s):  
Early Cretaceous ◽  
Three Dimensional ◽  
Micro Computed Tomography ◽  
Phylogenetic Studies ◽  
External Process ◽  
Orbital Wall ◽  
Postcranial Remains ◽  
Three Dimensional Models ◽  
Cranial Osteology

Pleurosternon bullockii is a turtle from the Early Cretaceous of Europe known from numerous postcranial remains. Only one skull has so far been referred to the species. Pleurosternon bullockii belongs to a group of turtles called pleurosternids, which is thought to include several poorly known taxa from the Late Jurassic and Early Cretaceous of Europe and North America. Pleurosternids and baenids, a group of North American turtles that lived from the Late Cretaceous to the Eocene, define a clade called Paracryptodira. Additionally, Paracryptodira likely includes compsemydids, and, potentially, helochelydrids. Character support for Paracryptodira is relatively weak, and many global phylogenetic studies fail to support paracryptodiran monophyly altogether. Proposed paracryptodiran synapomorphies are largely cranial, despite the poor characterization of pleurosternid cranial material. In addition to their questionable monophyly, the global position of paracryptodires is debated. Early studies suggest crown-turtle affinities, but most phylogenies find them as stem-turtles, irrespective of their monophyly. Here, we document the cranial osteology of Pleurosternon bullockii with the use of three-dimensional models derived from segmenting high-resolution X-ray micro-computed tomography (CT) scans. Pleurosternon bullockii has a primitive basipterygoid region of the skull, but a cryptodire-like acustico-jugular region. A surprising number of similarities with pleurodires exist, particularly in the laterally expanded external process of the pterygoid and in the posterior orbital wall. Our observations constitute an important step toward a phylogenetic re-evaluation of Paracryptodira.

scholarly journals Hidden impacts of ocean acidification to live and dead coral framework

2015 ◽  
Vol 282 (1813) ◽  
pp. 20150990 ◽  
Author(s):  
S. J. Hennige ◽  
L. C. Wicks ◽  
N. A. Kamenos ◽  
G. Perna ◽  
H. S. Findlay ◽  
...  
Keyword(s):  
Cold Water ◽  
Breaking Strength ◽  
Three Dimensional ◽  
Mechanical Damage ◽  
Skeletal Structure ◽  
Lophelia Pertusa ◽  
Dead Coral ◽  
Important Species ◽  
Structure Changes ◽  
Commercially Important

Cold-water corals, such as Lophelia pertusa , are key habitat-forming organisms found throughout the world's oceans to 3000 m deep. The complex three-dimensional framework made by these vulnerable marine ecosystems support high biodiversity and commercially important species. Given their importance, a key question is how both the living and the dead framework will fare under projected climate change. Here, we demonstrate that over 12 months L. pertusa can physiologically acclimate to increased CO 2 , showing sustained net calcification. However, their new skeletal structure changes and exhibits decreased crystallographic and molecular-scale bonding organization. Although physiological acclimatization was evident, we also demonstrate that there is a negative correlation between increasing CO 2 levels and breaking strength of exposed framework (approx. 20–30% weaker after 12 months), meaning the exposed bases of reefs will be less effective ‘load-bearers’, and will become more susceptible to bioerosion and mechanical damage by 2100.

Broad application of non-invasive imaging techniques to echinoids and other echinoderm taxa*

Zoosymposia ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. 53-70 ◽  
Author(s):  
ALEXANDER ZIEGLER
Keyword(s):  
Sea Urchin ◽  
Large Scale ◽  
Sea Urchins ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Image Data ◽  
Micro Computed Tomography ◽  
Non Invasive ◽  
Mri Scans ◽  
Three Dimensional Models

Tomographic imaging techniques such as micro-computed tomography (μCT) and magnetic resonance imaging (MRI) permit the gathering of digital anatomical data from whole animal specimens non-invasively. The resulting datasets can be used for direct observation of the two-dimensional tomographic image data as well as for manual and semi-automated three-dimensional modelling. Freshly fixed specimens as well as preserved museum material can be successfully ana­lyzed using this approach, giving the zoomorphologist a powerful tool for large-scale comparative studies. In order to demonstrate the principle suitability of non-invasive imaging in echinoderm research, μCT scans of 199 and MRI scans of 92 sea urchin (Echinodermata: Echinoidea) species were acquired, resulting in a total of 203 analyzed echinoid species. The taxa selected represent 50 of the currently recognized 60 extant sea urchin families. The present article lists all spe­cies that have been analyzed so far and provides information about the scanning parameters employed for each dataset. Furthermore, the workflow established to generate three-dimensional models of sea urchins is outlined. Using a number of examples from μCT as well as MRI scans performed on echinoids, the potential of the systematic approach described here is highlighted. Finally, the suitability of non-invasive imaging techniques for the study of other echinoderm taxa is assessed based on multimodal datasets of representative species.

scholarly journals Historic photographs of glaciers and glacial landforms from the R. S. Tarr collection at Cornell University

2019 ◽  
Author(s):  
Julie Elliott ◽  
Matthew E. Pritchard
Keyword(s):  
New York ◽  
Landscape Change ◽  
Three Dimensional ◽  
Gold Rush ◽  
Ecological Change ◽  
Cornell University ◽  
The Public ◽  
Three Dimensional Models ◽  
Glacial Landforms ◽  
First Time

Abstract. Historic photographs are useful for documenting glacier, environmental, and landscape change and we have digitized a collection of about 1949 images collected during an 1896 expedition to Greenland and trips to Alaska in 1905, 1906, 1909, and 1911, led by Ralph Stockman Tarr and his students at Cornell University. These images are openly available in the public domain through Cornell University Library (http://digital.library.cornell.edu/collections/tarr). The primary research targets of these expeditions were glaciers (there are about 990 photographs of at least 58 named glaciers) but there are also photographs of people, villages, geologic features, and formerly glaciated regions, including glacial features near Cornell University in Ithaca, New York. Some of the glaciers featured in the photographs have retreated significantly in the last century or even completely vanished. For many glaciers, multiple views are available, potentially allowing the use of photogrammetric techniques to generate three-dimensional models of the ice extent. While some of these photographs have been used in publications in the early 20th century, most of the images are only now widely available for the first time. The digitized collection also includes about 300 lantern slides made from the expedition photographs and other related images and used in classes and public presentations about glaciers and glaciations by several Cornell faculty over the decades. The images are of scientific interest for understanding glacier and ecological change, of public policy interest for documenting climate change, of historic and anthropological interest as local people, settlements, and gold-rush era paraphernalia are featured in the images, and of artistic and technological interest as the photographic techniques used were cutting-edge for their time.

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