Bony Patchwork: Mosaic Patterns of Evolution in the Skull of Electric Fishes (Apteronotidae: Gymnotiformes)

2019 ◽  
Vol 59 (2) ◽  
pp. 420-431 ◽  
Author(s):  
Kory M Evans ◽  
Marta Vidal-García ◽  
Victor A Tagliacollo ◽  
Samuel J Taylor ◽  
Dante B Fenolio
Keyword(s):  
Three Dimensional ◽  
Strong Support ◽  
Functional Specialization ◽  
Deep Time ◽  
Selective Pressures ◽  
Rates Of Evolution ◽  
Individual Traits ◽  
The Face ◽  
Electric Fishes ◽  
Mosaic Evolution

Abstract Mosaic evolution refers to the pattern whereby different organismal traits exhibit differential rates of evolution typically due to reduced levels of trait covariation through deep time (i.e., modularity). These differences in rates can be attributed to variation in responses to selective pressures between individual traits. Differential responses to selective pressures also have the potential to facilitate functional specialization, allowing certain traits to track environmental stimuli more closely than others. The teleost skull is a multifunctional structure comprising a complex network of bones and thus an excellent system for which to study mosaic evolution. Here we construct an ultrametric phylogeny for a clade of Neotropical electric fishes (Apteronotidae: Gymnotiformes) and use three-dimensional geometric morphometrics to investigate patterns of mosaic evolution in the skull and jaws. We find strong support for a developmental, three-module hypothesis that consists of the face, braincase, and mandible, and we find that the mandible has evolved four times faster than its neighboring modules. We hypothesize that the functional specialization of the mandible in this group of fishes has allowed it to outpace the face and braincase and evolve in a more decoupled manner. We also hypothesize that this pattern of mosaicism may be widespread across other clades of teleost fishes.

Molecular basis of adaptive evolution of sperm motility involved in in vivo fertilization of terrestrial animals

Impact ◽  
2020 ◽  
Vol 2020 (6) ◽  
pp. 73-75
Author(s):  
Akihiko Watanabe
Keyword(s):  
Sexual Reproduction ◽  
Sperm Motility ◽  
Asexual Reproduction ◽  
Acrosome Reaction ◽  
Sperm Morphology ◽  
Adaptive Potential ◽  
Selective Pressures ◽  
The Face ◽  
Genetic Profiles

One of the unifying traits of life on this planet is reproduction, or life's ability to make copies of itself. The mode of reproduction has evolved over time, having almost certainly begun with simple asexual reproduction when the ancestral single celled organism divided into two. Since these beginnings' life has tried out numerous strategies, and perhaps one of the most important and successful has been sexual reproduction. This form of reproduction relies on the union of gametes, otherwise known as sperm and egg. Evolutionarily, sexual reproduction allows for greater adaptive potential because the genes of two unique individuals have a chance to recombine and mix in order to produce a new individual. Unlike asexual reproduction which produces genetically-identical clones of the parent individual, sex produces offspring with novel genes and combinations of genes. Therefore, in the face of new selective pressures there is a higher chance that one of these novel genetic profiles will produce an adaptation that is advantageous in the new circumstances. Dr Akihiko Watanabe is a reproductive biologist based in the Department of Biology, Faculty of Science Yamagata University in Japan, he is currently working on three research projects; a comparative study on the signalling pathways for inducing sperm motility and acrosome reaction in amphibians, the mechanism behind the adaptive modification of sperm morphology and motility, and the origin of sperm motility initiating substance (SMIS).

Wake Flow of Single and Multiple Yawed Cylinders

2004 ◽  
Vol 126 (5) ◽  
pp. 861-870 ◽  
Author(s):  
A. Thakur ◽  
X. Liu ◽  
J. S. Marshall
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Side Wall ◽  
Wake Flow ◽  
Upstream Region ◽  
Two Dimensional ◽  
Cylinder Wake ◽  
Dimensional Approximation ◽  
The Face ◽  
Drag And Lift

An experimental and computational study is performed of the wake flow behind a single yawed cylinder and a pair of parallel yawed cylinders placed in tandem. The experiments are performed for a yawed cylinder and a pair of yawed cylinders towed in a tank. Laser-induced fluorescence is used for flow visualization and particle-image velocimetry is used for quantitative velocity and vorticity measurement. Computations are performed using a second-order accurate block-structured finite-volume method with periodic boundary conditions along the cylinder axis. Results are applied to assess the applicability of a quasi-two-dimensional approximation, which assumes that the flow field is the same for any slice of the flow over the cylinder cross section. For a single cylinder, it is found that the cylinder wake vortices approach a quasi-two-dimensional state away from the cylinder upstream end for all cases examined (in which the cylinder yaw angle covers the range 0⩽ϕ⩽60°). Within the upstream region, the vortex orientation is found to be influenced by the tank side-wall boundary condition relative to the cylinder. For the case of two parallel yawed cylinders, vortices shed from the upstream cylinder are found to remain nearly quasi-two-dimensional as they are advected back and reach within about a cylinder diameter from the face of the downstream cylinder. As the vortices advect closer to the cylinder, the vortex cores become highly deformed and wrap around the downstream cylinder face. Three-dimensional perturbations of the upstream vortices are amplified as the vortices impact upon the downstream cylinder, such that during the final stages of vortex impact the quasi-two-dimensional nature of the flow breaks down and the vorticity field for the impacting vortices acquire significant three-dimensional perturbations. Quasi-two-dimensional and fully three-dimensional computational results are compared to assess the accuracy of the quasi-two-dimensional approximation in prediction of drag and lift coefficients of the cylinders.

scholarly journals Shifts in morphology, gene expression, and selection underlie web loss in Hawaiian Tetragnatha spiders

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cory A. Berger ◽  
Michael S. Brewer ◽  
Nobuaki Kono ◽  
Hiroyuki Nakamura ◽  
Kazuharu Arakawa ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Adaptive Traits ◽  
Deep Time ◽  
Selective Pressures ◽  
Silk Production ◽  
Silk Glands ◽  
Genetic Mechanisms ◽  
Orb Web ◽  
Short Time ◽  
Web Building

Abstract Background A striking aspect of evolution is that it often converges on similar trajectories. Evolutionary convergence can occur in deep time or over short time scales, and is associated with the imposition of similar selective pressures. Repeated convergent events provide a framework to infer the genetic basis of adaptive traits. The current study examines the genetic basis of secondary web loss within web-building spiders (Araneoidea). Specifically, we use a lineage of spiders in the genus Tetragnatha (Tetragnathidae) that has diverged into two clades associated with the relatively recent (5 mya) colonization of, and subsequent adaptive radiation within, the Hawaiian Islands. One clade has adopted a cursorial lifestyle, and the other has retained the ancestral behavior of capturing prey with sticky orb webs. We explore how these behavioral phenotypes are reflected in the morphology of the spinning apparatus and internal silk glands, and the expression of silk genes. Several sister families to the Tetragnathidae have undergone similar web loss, so we also ask whether convergent patterns of selection can be detected in these lineages. Results The cursorial clade has lost spigots associated with the sticky spiral of the orb web. This appears to have been accompanied by loss of silk glands themselves. We generated phylogenies of silk proteins (spidroins), which showed that the transcriptomes of cursorial Tetragnatha contain all major spidroins except for flagelliform. We also found an uncharacterized spidroin that has higher expression in cursorial species. We found evidence for convergent selection acting on this spidroin, as well as genes involved in protein metabolism, in the cursorial Tetragnatha and divergent cursorial lineages in the families Malkaridae and Mimetidae. Conclusions Our results provide strong evidence that independent web loss events and the associated adoption of a cursorial lifestyle are based on similar genetic mechanisms. Many genes we identified as having evolved convergently are associated with protein synthesis, degradation, and processing, which are processes that play important roles in silk production. This study demonstrates, in the case of independent evolution of web loss, that similar selective pressures act on many of the same genes to produce the same phenotypes and behaviors.

scholarly journals 3D FEM Model on the Parameters’ Influence of EPB-TBM on Settlements of Single and Twin Metro Tunnels During Construction

2021 ◽  
Author(s):  
Masoud Forsat ◽  
Mohammad Taghipoor ◽  
Masoud Palassi
Keyword(s):  
Three Dimensional ◽  
Injection Pressure ◽  
Effective Parameters ◽  
Grout Injection ◽  
3D Fem ◽  
Supporting Pressure ◽  
Epb Tbm ◽  
The Face ◽  
Clear Distance ◽  
Twin Tunnels

AbstractThe present research exposes the investigation on three-dimensional modeling of the single and twin metro tunnels for the case of the Tehran metro line. At first, simulation implemented on the comparison of the ground movements in the single and twin tunnels. Then the simulation has been performed on the influence of effective parameters of EPB-TBM on the surface settlements throughout excavation. The overcutting, shield conicity, grouting, and the final lining system modeled and the influence of face supporting pressure, grout injection pressure, as well as the clear distance of the tunnels, has been analyzed. The initial results showed a valid ground settlement behavior. The maximum settlements occurred at the end of the shield tail and it was higher in the single tunnel. The face supporting pressure had more effect on the surface settlement in comparison to the grout injection pressure. By increasing the face pressure in the single tunnel, the place of maximum settlement moved back while the grout pressure is insignificant for decreasing the settlements. Furthermore, the influence of the clear distance in the twin tunnels led to zero after the length of 30 m. Accordingly, for more distances, the tunnels must be examined independently and as two different single tunnels.

Three Dimensional Numerical Analyses of Bridge Piled-Raft Foundation under Riverbed Erosion

2012 ◽  
Vol 178-181 ◽  
pp. 2373-2377 ◽  
Author(s):  
Wen Tsung Liu ◽  
Yi Yi Li
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Bridge Piers ◽  
Piled Raft Foundation ◽  
River Erosion ◽  
Dimensional Finite Element ◽  
The Face ◽  
Three Dimensional Finite Element

From the 921 earthquake to the major typhoons, including the Morakot typhoon, they damaged original landscape of rivers in Taiwan. In recent years, it alleged that abutment bridge exposed to the most serious security problems. Because of bridge piers in addition to the face of long-term river erosion, the flood on the pier will produce localized erosion near the bridge. The pier will be due to inadequate bearing capacity, resulting in subsidence, displacement, bridge version accompanied by tilting and even caving. The river erosion of soil around the piers deposits and production of contraction will often reduce the bearing capacity. Therefore, how to accurately estimate the scour depth, calculate piers to withstand water impact and analyses its stability for preventing injuries in the first place is the current pressing issues. In this study, three-dimensional finite element method (FEM) analysis program Plaxis 3D foundation is used. Polaris second bridge is selected for analysis. Based on local scouring of the model and various numerical variable conditions, the parameter of bridge pier is studied.

Did They Mind the Gap? Voter/Party Ideological Proximity between the BQ, the NDP and Quebec Voters, 2006–2011

2016 ◽  
Vol 49 (2) ◽  
pp. 289-310 ◽  
Author(s):  
Jean-Philippe Gauvin ◽  
Chris Chhim ◽  
Mike Medeiros
Keyword(s):  
Political Party ◽  
Three Dimensional ◽  
Election Study ◽  
Federal Election ◽  
Party Manifestos ◽  
Longitudinal Approach ◽  
The Face ◽  
Election Results ◽  
Using Data ◽  
Over Time

AbstractThe 2011 Canadian federal election results changed the face of federal politics in Quebec. In a sudden and spectacular reversal of electoral fortunes, BQ support crumbled while that of the NDP surged. While most commentators focused exclusively on the 2011 election itself to explain what had happened, we offer an interpretation that takes a longitudinal approach. Using data from the Canadian Election Study and political party manifestos from 2006 to 2011, we propose a three-dimensional proximity model of voter/party congruence to explore the evolution of the ideological stances of Quebec voters and parties. Empirical results suggest these ideological distances between the NDP and Quebec voters decreased over time, whereas the BQ has distanced itself from voters. Furthermore, ideological distances between party and voters are a significant predictor of vote.

Preliminary Evaluation of an Electromagnetic Three-Dimensional Digitizer in Facial Anthropometry

1998 ◽  
Vol 35 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Virgilio F. Ferrario ◽  
Chiarella Sforza ◽  
Carlo E. Poggio ◽  
Massimiliano Cova ◽  
Gianluca Tartaglia
Keyword(s):  
Three Dimensional ◽  
Preliminary Evaluation ◽  
Men And Women ◽  
Facial Landmarks ◽  
Coefficients Of Variation ◽  
The Face ◽  
Human Adults ◽  
Facial Anthropometry ◽  
Sufficient Precision

Objective In this investigation, the precision of a commercial three-dimensional digitizer in the detection of facial landmarks in human adults was assessed. Methods Fifty landmarks were identified and marked on the faces of five men, on five women, and on a stone cast of the face of one man. For each subject, the three-dimensional coordinates of the landmarks were obtained twice using an electromagnetic three-dimensional digitizer, and the duplicate digitizations were superimposed using common orientations and centers of gravity. Metric differences between homologous landmarks were assessed, and Dahlberg's error was computed. Results For both men and women, the error was 1.05% of the nasion-mid-tragion distance, while for the cast, it was 0.9%. When the duplicate digitizations were used to mathematically reconstruct the faces, and several distances, angles, volumes, and surfaces were computed, more than 80% of the measurements had coefficients of variation lower than 1%. Conclusions The digitizer can assess the coordinates of facial landmarks with sufficient precision, and reliable measurements can be obtained.

Recognising Facial Surfaces

Perception ◽  
1991 ◽  
Vol 20 (6) ◽  
pp. 755-769 ◽  
Author(s):  
Vicki Bruce ◽  
Patrick Healey ◽  
Mike Burton ◽  
Tony Doyle ◽  
Anne Coombes ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Head Model ◽  
Matching Accuracy ◽  
The People ◽  
Computer Aided ◽  
Closed Head ◽  
The Face ◽  
Aided Design ◽  
Dimensional Surface

The extent to which faces depicted as surfaces devoid of pigmentation and with minimal texture cues (‘head models’) could be matched with photographs (when unfamiliar) and identified (when familiar) was examined in three experiments. The head models were obtained by scanning the three-dimensional surface of the face with a laser, and by displaying the surface measured in this way by using standard computer-aided design techniques. Performance in all tasks was above chance but far from ceiling. Experiment 1 showed that matching of unfamiliar head models with photographs was affected by the resolution with which the surface was displayed, suggesting that subjects based their decisions, at least in part, on three-dimensional surface structure. Matching accuracy was also affected by other factors to do with the viewpoints shown in the head models and test photographs, and the type of lighting used to portray the head model. In experiment 2 further evidence for the importance of the nature of the illumination used was obtained, and it was found that the addition of a hairstyle (not that of the target face) did not facilitate matching. In experiment 3 identification of the head models by colleagues of the people shown was compared with identification of photographs where the hair was concealed and eyes were closed. Head models were identified less well than these photographs, suggesting that the difficulties in their recognition are not solely due to the lack of hair. Women's heads were disproportionately difficult to recognise from the head models. The results are discussed in terms of their implications for the use of such three-dimensional head models in forensic and surgical applications.

scholarly journals R.T. Erdogan as an Example of a Charismatic Politician

2018 ◽  
Vol 10 (6) ◽  
pp. 138-154 ◽  
Author(s):  
V. A. Nadein-Raevskiy
Keyword(s):  
Religious Education ◽  
Good Practice ◽  
Strong Support ◽  
Armed Forces ◽  
Political Support ◽  
The Political ◽  
Justice And Development Party ◽  
The Face ◽  
National Salvation ◽  
Hizmet Movement

The article examines the process of formation of identity of Turkish President Recep Tayyip Erdogan – a charismatic leader, an adept of “moderate Islamism” one of the founders of the Justice and Development Party. Historically strong centralized authority was always normal for Turkey and the need for Turks in the charismatic leaders is evident even at the present time. Erdogan is stubborn and consistent, thanking to religious education in his family and in religious Lyceum Imam Hatib. He was always religious and since his student years, joined Islamic politicians. In his student years he became the head of the Istanbul Youth organization of the Islamist National Salvation Party, in whose ranks and files he received good practice of a political organizer. The crisis in the ranks of the Islamists after repeated bans of the Islamist party led to a split in its ranks and Erdogan and his associates established the Justice and Development Party (AKP). Creating the AKP, Erdogan and his colleagues received a very important support from the well-known Muslim preacher, writer and philosopher Fethullah Gülen living in Pennsylvania (USA). The political support of Gülen who has millions of followers in Turkey and a well-organized educational system of the “Hizmet” Movement operating not only in Turkey but also in 140 countries helped the AKP to win the elections to the Turkish Parliament. Numerous graduates of private schools, colleges and universities of F. Gülen has occupied leading positions in business, police, juridical structures and the armed forces of Turkey and became supporters of Erdogan. Economic reforms of the AKP has substantially strengthened the Turkish economy, increased the income of the population and managed to cope successfully with inflation. On this ground Erdogan’s credibility consequently grew in the face of voters who saw him a successful leader and skilled politician. However, Erdogan gradually returned to the daily life of Turks the Islamic religion, which caused discontent among the supporters of secular development of the country. Repeated attempts to remove the AKP from power were not successful. Using strong support from F. Gülen’s structures in the judiciary, Erdogan managed to organize high-profile lawsuits against the army leadership, politicians, and journalists – supporters of secular development of the country. In a popular referendum, the army was excluded from influence on the political system of the country. However, constant criticism of the policies of Erdogan from the side of F. Gülen led to the crisis of union between the two leaders. Using the failed coup attempt Erdogan accused in its organization Fethullah Gülen and began a wide crackdown against his supporters. 

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