Palaeobiology of the reclining rangeomorph Beothukis from the Ediacaran Mistaken Point Formation of southeastern Newfoundland

2020 ◽  
pp. 1-15
Author(s):  
Duncan McIlroy ◽  
Jessica Hawco ◽  
Christopher McKean ◽  
Robert Nicholls ◽  
Giovanni Pasinetti ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Surface Area ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Lower Surface ◽  
Basal Region ◽  
Mode Of Life ◽  
Primary Order ◽  
Increase Surface Area

Abstract Beothukis mistakensis from the Ediacaran System of Newfoundland, Canada demonstrates complex fractal-like morphology through the development of primary-, secondary- and tertiary-order Rangea-like units. The primary-order rangeomorph units observed in B. mistakensis are tightly juxtaposed, show no evidence of being independent of one another and are made up of chamber-like secondary-order – probably mesoglea-filled – units. The growth of these rangeomorph units demonstrates that the frond developed from the tip towards the basal region through ontogeny. The tertiary-order units of Beothukis are considered to represent surface morphology on the secondary-order units. This is in contrast to palaeobiological reconstructions of Beothukis that invoke three-dimensional fractal-like branches with independent units, which has been used to infer an osmotrophic mode of life. It is considered here that the fractal-like morphology of the lower surface of B. mistakensis was an adaptation to increase surface area to volume ratio. The quilted morphology of Beothukis proposed here is consistent with a sessile, reclining, phagocytotic and/or chemosymbiotic mode of life similar to that invoked for the reclining rangeomorph Fractofusus.

scholarly journals Road salt compromises functional morphology of larval gills in populations of an amphibian

2020 ◽  
Author(s):  
Richard V. Szeligowski ◽  
Jules A. Scanley ◽  
Christine C. Broadbridge ◽  
Steven P. Brady
Keyword(s):  
Gas Exchange ◽  
Ion Exchange ◽  
Surface Area ◽  
Volume Ratio ◽  
Rana Sylvatica ◽  
Early Life History ◽  
Lower Surface ◽  
Secondary Salinization ◽  
Elevated Salinity ◽  
Gill Morphology

AbstractThroughout much of the world, winter deicing practices have led to secondary salinization of freshwater habitats, where numerous taxa are vulnerable to elevated salinity. Many amphibians are of particular concern because of their permeable skin and reliance on small ponds and pools, where salinity levels can be high. The early life-history stages of amphibians that develop in these habitats are especially sensitive to salt exposure. Larvae developing in salt-polluted environments must osmoregulate through ion exchange in gills. While salt-induced changes to the physiology of ion exchange in amphibian gills is generally understood, functionally relevant changes in gill morphology remain poorly described. Yet the structure of gills should be an important component affecting their ionoregulatory capacity, for instance in terms available surface area. Larval amphibian gills also play critical roles in gas exchange and foraging. Thus, changes in gill morphology due to salt pollution potentially affect not only osmoregulation, but also respiration and feeding. Here, we used a chronic exposure experiment to quantify the effect of salinity on larval gill morphology in populations of the wood frog (Rana sylvatica). We measured a suite of morphological traits on gill tufts, where ionoregulation and gas exchange occur, and on gill filters, which are used in feeding. Larvae raised in high salinity conditions had gill tufts with lower surface area to volume ratio, while epithelial cells on these tufts were less circular but occurred at higher densities. Gill filters showed increased spacing, which can potentially reduce their efficiency in filtering food particles. Together, these changes seem likely to diminish the ionoregulatory and respiratory capacity of gill tufts, and compromise feeding functionality of gill filters. Thus, a singular change in the aquatic environment from a widespread pollutant has the potential to generate a suite of consequences via changes in gill morphology. Critically, this suite of negative effects is likely most detrimental in salinized environments, where ionoregulatory demands are higher, which in turn should increase respiratory demands along with energy acquisition demands through foraging.

Taphonomic field experiment in a freshwater shallow lake: alteration of gastropod shells below the sediment–water interface

2019 ◽  
Vol 85 (4) ◽  
pp. 404-413 ◽  
Author(s):  
Paula Andrea Cristini ◽  
Claudio Germán De Francesco
Keyword(s):  
Field Experiment ◽  
Surface Area ◽  
Volume Ratio ◽  
Lower Surface ◽  
Pomacea Canaliculata ◽  
Water Interface ◽  
Shell Surface ◽  
Shell Size ◽  
Surface Alteration ◽  
Pampa Plain

Abstract We conducted a taphonomic field experiment to evaluate the effects of (1) depth below the sediment–water interface (SWI) and (2) time of exposure on the accrual of damage (particularly through dissolution) to empty mollusc shells in freshwater environments. The experiment, which lasted 30 months, was carried out in the littoral area of Lake Nahuel Rucá, a shallow freshwater lake in the Pampa plain of Argentina. Bags (0.5-cm mesh) containing empty, cleaned shells of the freshwater gastropods Heleobia parchappii, Biomphalaria peregrina and Pomacea canaliculata were buried at three different depths (5, 20 and 35 cm) below the SWI. Damage was assessed every 3 months. All experimental shells exhibited fine-scale surface alteration, but the extent of this damage was relatively low, even in shells recovered after 30 months of exposure. Most of the damage consisted of minor pitting. For H. parchappii and B. peregrina, shell surface alteration varied significantly with depth, but not with time; in both species, alteration occurred mainly at the beginning of the experiment. For P. canaliculata, shell surface alteration varied significantly only with respect to time and this was the case for all three burial depths. All shells of this species exhibited a lower level of damage than what was observed for H. parchappii and B. peregrina. These differences may be related to the fact that P. canaliculata is characterized by a larger and thicker shell than the other two species. The shell attributes of larger size and greater thickness are known to confer a greater resistance to shell dissolution. In addition, the reactive surface area available for dissolution varies with shell size. Larger-sized shells have a lower potential for dissolution than smaller shells due to their lower surface-area-to-volume ratio. In contrast, species such as H. parchappii and B. peregrina, which have smaller and thinner shells, are likely to be more rapidly destroyed because they are more vulnerable to dissolution and have less preservation potential. Our results demonstrate that dissolution is a significant taphonomic process affecting shells even during burial and that the influence of dissolution on shell alteration might be significant in cases of long persistence within the taphonomically active zone. Consequently, we suggest that when working on taphofacies in the context of aquatic environments, assessments of taphonomic alteration should include changes at and below the SWI.

scholarly journals Study of Sexual Dimorphism in Metatarsal Bones: Geometric and Inertial Analysis of the Three-Dimensional Reconstructed Models

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaming Liu ◽  
Djorde Antonijević ◽  
Ruining Li ◽  
Yuxuan Fan ◽  
Ksenija Dukić ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Surface Area ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Discriminant Functions ◽  
Moments Of Inertia ◽  
Principal Moments Of Inertia ◽  
Metatarsal Bones ◽  
The Individual ◽  
Bone Height

The aim of the present paper is to determine the sex of the individual using three-dimensional geometric and inertial analyses of metatarsal bones. Metatarsals of 60 adult Chinese subjects of both sexes were scanned using Aquilion One 320 Slice CT Scanner. The three-dimensional models of the metatarsals were reconstructed, and thereafter, a novel software using the center of mass set as the origin and the three principal axes of inertia was employed for model alignment. Eight geometric and inertial variables were assessed: the bone length, bone width, bone height, surface-area-to-volume ratio, bone density, and principal moments of inertia around the x, y, and z axes. Furthermore, the discriminant functions were established using stepwise discriminant function analysis. A cross-validation procedure was performed to evaluate the discriminant accuracy of functions. The results indicated that inertial variables exhibit significant sexual dimorphism, especially principal moments of inertia around the z axis. The highest dimorphic values were found in the surface-area-to-volume ratio, principal moments of inertia around the z axis, and bone height. The accuracy rate of the discriminant functions for sex determination ranged from 88.3% to 98.3% (88.3%–98.3% cross-validated). The highest accuracy of function was established based on the third metatarsal bone. This study showed for the first time that the principal moment of inertia of the human bone may be successfully implemented for sex estimation. In conclusion, the sex of the individual can be accurately estimated using a combination of geometric and inertial variables of the metatarsal bones. The accuracy should be further confirmed in a larger sample size and be tested or independently developed for distinct population/age groups before the functions are widely applied in unidentified skeletons in forensic and bioarcheological contexts.

scholarly journals Plasticity in Three-Dimensional Geometry of Branching Corals Along a Cross-Shelf Gradient

Diversity ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 44 ◽  
Author(s):  
Neil Doszpot ◽  
Michael McWilliam ◽  
Morgan Pratchett ◽  
Andrew Hoey ◽  
Will Figueira
Keyword(s):  
Surface Area ◽  
Environmental Gradients ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Morphological Plasticity ◽  
Outer Shelf ◽  
Individual Species ◽  
Inner Shelf ◽  
Stylophora Pistillata ◽  
Wide Range

Scleractinian corals often exhibit high levels of morphological plasticity, which is potentially important in enabling individual species to occupy benthic spaces across a wide range of environmental gradients. This study tested for differences in the three-dimensional (3D) geometry of three branching corals, Acropora nasuta, Pocillopora spp. and Stylophora pistillata among inner-, mid- and outer-shelf reefs in the central Great Barrier Reef, Australia. Important attributes of coral morphology (e.g., surface area to volume ratio) were expected to vary linearly across the shelf in accordance with marked gradients in environmental conditions, but instead, we detected non-linear trends in the colony structure of A. nasuta and Pocillopora spp. The surface area to volume ratio of both A. nasuta and Pocillopora spp. was highest at mid-shelf locations, (reflecting higher colony complexity) and was significantly lower at both inner-shelf and outer-shelf reefs. The branching structure of these corals was also far more tightly packed at inner-shelf and outer-shelf reefs, compared to mid-shelf reefs. Apparent declines in complexity and inter-branch spacing at inner and outer-shelf reefs (compared to conspecifics from mid-shelf reefs) may reflect changes driven by gradients of sedimentation and hydrodynamics. The generality and explanations of observed patterns warrant further investigation, which is very feasible using the 3D-photogrammetry techniques used in this study.

scholarly journals Quantum transport in three-dimensional metalattices of platinum featuring an unprecedentedly large surface area to volume ratio

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Yixuan Chen ◽  
Yunzhi Liu ◽  
Parivash Moradifar ◽  
Andrew J. Glaid ◽  
Jennifer L. Russell ◽  
...  
Keyword(s):  
Surface Area ◽  
Quantum Transport ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Large Surface Area

Low-Degree Tibial Slope Angle Prevents Component Overhang by Enlarging the Lateral Plateau Surface Area in Total Knee Arthroplasty

2020 ◽  
Author(s):  
Mehmet Emin Simsek ◽  
Mustafa Akkaya ◽  
Safa Gursoy ◽  
Özgür Kaya ◽  
Murat Bozkurt
Keyword(s):  
Total Knee Arthroplasty ◽  
Surface Area ◽  
Knee Arthroplasty ◽  
Tibial Plateau ◽  
Slope Angle ◽  
Three Dimensional ◽  
Tibial Slope ◽  
Total Knee ◽  
Lateral Plateau ◽  
Gender Groups

AbstractThis study aimed to investigate whether overhang or underhang around the tibial component that occurs during the placement of tibial baseplates was affected by different slope angles of the tibial plateau and determine the changes in the lateral and medial plateau diameters while changing the slope angle in total knee arthroplasty. Three-dimensional tibia models were reconstructed using the computed tomography scans of 120 tibial dry bones. Tibial plateau slope cuts were performed with 9, 7, 5, 3, and 0 degrees of slope angles 2-mm below the subchondral bone in the deepest point of the medial plateau. Total, lateral, and medial tibial plateau areas and overhang/underhang rates were measured at each cut level. Digital implantations of the asymmetric and symmetric tibial baseplates were made on the tibial plateau with each slope angles. Following the implantations, the slope angle that prevents overhang or underhang at the bone border and the slope angle that has more surface area was identified. A significant increase was noted in the total tibial surface area, lateral plateau surface area, and lateral anteroposterior distance, whereas the slope cut angles were changed from 9 to 0 degrees in both gender groups. It was found that the amount of posteromedial underhang and posterolateral overhang increased in both the asymmetric and symmetric tibial baseplates when the slope angle was changed from 0 to 9 degrees. Although the mediolateral diameter did not change after the proximal tibia cuts at different slope angles, the surface area and anteroposterior diameter of the lateral plateau could change, leading to increased lateral plateau area. Although prosthesis designs are highly compatible with the tibial surface area, it should be noted that the component overhangs, especially beyond the posterolateral edge, it can be prevented by changing the slope cut angle in males and females.

3D reconstruction and calculation of surface area and volume of bell pepper

2007 ◽  
Vol 3 (1) ◽  
pp. 89-113
Author(s):  
Zoltán Gillay ◽  
László Fenyvesi
Keyword(s):  
3D Reconstruction ◽  
Surface Area ◽  
Three Dimensional ◽  
Reference Method ◽  
Bell Pepper ◽  
Three Dimensional Model ◽  
Acceptable Error ◽  
Volume Calculation ◽  
Bell Peppers ◽  
Area And Volume

There was a method developed that generates the three-dimensional model of not axisymmetric produce, based on an arbitrary number of photos. The model can serve as a basis for calculating the surface area and the volume of produce. The efficiency of the reconstruction was tested on bell peppers and artificial shapes. In case of bell peppers 3-dimensional reconstruction was created from 4 images rotated in 45° angle intervals. The surface area and the volume were estimated on the basis of the reconstructed area. Furthermore, a new and simple reference method was devised to give precise results for the surface area of bell pepper. The results show that this 3D reconstruction-based surface area and volume calculation method is suitable to determine the surface area and volume of definite bell peppers with an acceptable error.

Evaluation of Nanotechniques and Conventional Techniques for the Removal of Dioxins

2018 ◽  
Vol 9 (1) ◽  
pp. 79-84
Author(s):  
Vaishali V. Shahare ◽  
Rajni Grover ◽  
Suman Meena
Keyword(s):  
Soil Sample ◽  
Human Health ◽  
Surface Area ◽  
Contaminated Soil ◽  
Conventional Treatment ◽  
Volume Ratio ◽  
Soil Samples ◽  
Dioxins And Furans ◽  
Palladized Iron ◽  
The Impact

Background: The persistent dioxins/furans has caused a worldwide concern as they influence the human health. Recent research indicates that nonmaterial may prove effective in the degradation of Dioxins/furans. The nanomaterials are very reactive owing to their large surface area to volume ratio and large number of reactive sites. However, nanotechnology applications face both the challenges and the opportunities to influence the area of environmental protection. Objective: i) To study the impact of oil mediated UV-irradiations on the removal of 2,3,7,8-TCDD, 2,3,7,8-TCDF, OCDD and OCDF in simulated soil samples. ii) To compare the conventional treatment methods with the modern available nanotechniques for the removal of selected Dioxins/furans from soil samples. Methods: The present work has investigated an opportunity of the degradation of tetra and octachlorinated dioxins and furans by using oil mediated UV radiations with subsequent extraction of respective dioxins/furans from soils. The results have been compared with the available nanotechniques. Results: The dioxin congeners in the simulated soil sample showed decrease in concentration with the increase in the exposure time and intensity of UV radiations. The dechlorination of PCDD/Fs using palladized iron has been found to be effective. Conclusion: Both the conventional methods and nanotechnology have a dramatic impact on the removal of Dioxins/furans in contaminated soil. However, the nanotechniques are comparatively costlier and despite the relatively high rates of PCDDs dechlorination by Pd/nFe, small fraction of the dioxins are recalcitrant to degradation over considerable exposure times.

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