A multivariate approach to infer locomotor modes in Mesozoic mammals

Paleobiology ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 280-312 ◽  
Author(s):  
Meng Chen ◽  
Gregory P. Wilson
Keyword(s):  
Multivariate Analyses ◽  
Canonical Variate ◽  
Postcranial Skeleton ◽  
Morphometric Data ◽  
Linear Measurements ◽  
Data Set ◽  
Limited Region ◽  
Selective Pressures ◽  
Mesozoic Mammals ◽  
Long Time

AbstractEcomorphological diversity of Mesozoic mammals was presumably constrained by selective pressures imposed by contemporary vertebrates. In accordance, Mesozoic mammals for a long time had been viewed as generalized, terrestrial, small-bodied forms with limited locomotor specializations. Recent discoveries of Mesozoic mammal skeletons with distinctive postcranial morphologies have challenged this hypothesis. However, ecomorphological analyses of these new postcrania have focused on a single taxon, a limited region of the skeleton, or have been largely qualitative.For more comprehensive locomotor inference in Mesozoic mammals, we applied multivariate analyses to a morphometric data set of extant small-bodied mammals. We used 30 osteological indices derived from linear measurements of appendicular skeletons of 107 extant taxa that sample 15 orders and eight locomotor modes. Canonical variate analyses show that extant small-bodied mammals of different locomotor modes have detectable and predictable morphologies. The resulting morphospace occupation reveals a morphofunctional continuum that extends from terrestrial to scansorial, arboreal, and gliding modes, reflecting an increasingly slender postcranial skeleton with longer limb output levers adapted for speed and agility, and extends from terrestrial to semiaquatic/semifossorial and fossorial modes, reflecting an increasingly robust postcranial skeleton with shorter limb output levers adapted for powerful, propulsive strokes. We used this morphometric data set to predict locomotor mode in ten Mesozoic mammals within the Docodonta, Multituberculata, Eutriconodonta, “Symmetrodonta,” and Eutheria. Our results indicate that these fossil taxa represent five of eight locomotor modes used to classify extant taxa in this study, in some cases confirming and in other cases differing from prior ecomorphological assessments. Together with previous locomotor inferences of 19 additional taxa, these results show that by the Late Jurassic mammals had diversified into all but the saltatorial and active flight locomotor modes, and that this diversification was greatest in the Eutriconodonta and Multituberculata, although sampling of postcranial skeletons remains uneven across taxa and through time.

Quantifying tooth variation within a single population of Albertosaurus sarcophagus (Theropoda: Tyrannosauridae) and implications for identifying isolated teeth of tyrannosauridsThis article is one of a series of papers published in this Special Issue on the theme Albertosaurus.

2010 ◽  
Vol 47 (9) ◽  
pp. 1227-1251 ◽  
Author(s):  
Lisa G. Buckley ◽  
Derek W. Larson ◽  
Miriam Reichel ◽  
Tanya Samman
Keyword(s):  
Multivariate Analyses ◽  
Phylogenetic Signal ◽  
A Priori ◽  
Principal Component ◽  
Canonical Variate ◽  
Large Sample Size ◽  
Data Set ◽  
Theropod Dinosaurs ◽  
Degree Of Separation ◽  
Lower Maastrichtian

Documenting variation in theropod dinosaurs is usually hindered by the lack of a large sample size and specimens representing several ontogenetic stages. Here, variation within 140 disassociated and seven in situ tyrannosaur teeth from the Upper Cretaceous (lower Maastrichtian) monodominant Albertosaurus sarcophagus (Theropoda: Tyrannosauridae) bonebed is documented. This sample represents the largest data set of teeth from one population of A. sarcophagus containing both adult and juvenile specimens. Tooth variation was assessed using multivariate analyses (principal component, discriminant, and canonical variate analyses). Heterodonty in the teeth of A. sarcophagus contributes to the large amount of variation in the data set. Premaxillary teeth are significantly different from maxillary and dentary teeth, but there is no quantifiable difference between a priori identified maxillary and dentary teeth. Juvenile and adult teeth of A. sarcophagus show apparent quantitative differences that are size dependent on closer investigation, suggesting a cautious approach when interpreting multivariate analyses to identify novel tooth morphologies. Multivariate analyses on teeth of A. sarcophagus and published tooth data from other North American tyrannosaurid species reveals species-level clusters with little separation. The degree of separation among tooth clusters may reveal a phylogenetic signal in tyrannosaurid teeth.

Calcareous nannoplankton ecology and community change across the Paleocene-Eocene Thermal Maximum

Paleobiology ◽  
10.1666/12050 ◽  
2013 ◽  
Vol 39 (4) ◽  
pp. 628-647 ◽  
Author(s):  
Leah J. Schneider ◽  
Timothy J. Bralower ◽  
Lee R. Kump ◽  
Mark E. Patzkowsky
Keyword(s):  
Nutrient Availability ◽  
Multivariate Analyses ◽  
Geochemical Modeling ◽  
Community Change ◽  
Open Ocean ◽  
Data Set ◽  
Long Term Effect ◽  
Term Change ◽  
Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM; ca. 55.8 Ma) is thought to coincide with a profound but entirely transient change among nannoplankton communities throughout the ocean. Here we explore the ecology of nannoplankton during the PETM by using multivariate analyses of a global data set that is based upon the distribution of taxa in time and space. We use these results, coupled with stable isotope data and geochemical modeling, to reinterpret the ecology of key genera. The results of the multivariate analyses suggest that the community was perturbed significantly in coastal and high-latitudes sites compared to the open ocean, and the relative influence of temperature and nutrient availability on the assemblage varies regionally. The open ocean became more stratified and less productive during the PETM and the oligotrophic assemblage responded primarily to changes in nutrient availability. Alternatively, assemblages at the equator and in the Southern Ocean responded to temperature more than to nutrient reduction. In addition, the assemblage change at the PETM was not merely transient—there is evidence of adaptation and a long-term change in the nannoplankton community that persists after the PETM and results in the disappearance of a high-latitude assemblage. The long-term effect on communities caused by transient warming during the PETM has implications for modern-day climate change, suggesting similar permanent changes to nannoplankton community structure as the oceans warm.

scholarly journals Virologic Response to Lopinavir-Ritonavir-Based Antiretroviral Regimens in a Multicenter International Clinical Cohort: Comparison of Genotypic Interpretation Scores

2008 ◽  
Vol 52 (11) ◽  
pp. 4050-4056 ◽  
Author(s):  
Philip Grant ◽  
Eric C. Wong ◽  
Richard Rode ◽  
Robert Shafer ◽  
Andrea De Luca ◽  
...  
Keyword(s):  
Viral Load ◽  
Multivariate Analyses ◽  
Virologic Response ◽  
Receiver Operator Characteristic ◽  
Independent Data ◽  
Data Set ◽  
Clinical Cohort ◽  
Multicenter Cohort ◽  
Mutation Score ◽  
Clinical Breakpoints

ABSTRACT Several genotypic interpretation scores have been proposed for the evaluation of susceptibility to lopinavir/ritonavir (LPV/r) but have not been compared using an independent data set. This study was a retrospective multicenter cohort of patients initiating LPV/r-based therapy. The virologic response (VR) was defined as a viral load of <500 copies/ml at week 24. The genotypic interpretation scores surveyed were the LPV mutation score, the ViroLogic score, the ATU score, the Stanford database score, and the International AIDS Society-USA mutation list. Of the 103 patients included in the analysis, 76% achieved VR at 24 weeks. For scores with clinical breakpoints defined (LPV mutation, ATU, ViroLogic, and Stanford), over 80% of the patients below the breakpoints achieved VR, while 50% or less above the breakpoints responded. Protease mutations at positions 10, 54, and 82 and at positions 54, 84, and 90 were associated with a lack of VR in the univariate and multivariate analyses, respectively. The area under the receiver-operator characteristic curves for the five genotypic interpretation scores studied ranged from 0.73 to 0.76. The study confirms that the currently available genotypic interpretation scores which are widely used by clinicians performed similarly well and can be effectively used to predict the virologic activity of LPV/r in treatment-experienced patients.

Comparativa de modelos multivariados basados en aprendizaje automático para la predicción del riesgo de diabetes en etapas tempranas

2021 ◽  
Author(s):  
◽  
Zayra Ramírez Gaytán
Keyword(s):  
World Health ◽  
Degenerative Diseases ◽  
Decision Tree Algorithm ◽  
Data Set ◽  
The World ◽  
Long Time ◽  
Life Threatening ◽  
Health Organization ◽  
Logistic Regression Algorithm ◽  
Asymptomatic Phase

Diabetes is one of the fastest-growing, life-threatening, chronic degenerative diseases. According to the World Health Organization (WHO), it has affected 422 million people worldwide in 2018. Approximately 50% of all people who suffer diabetes are not diagnosed due to the asymptomatic phase which usually lasts a long time. In this work, a data set of 520 instances has been used. The data set has been analyzed with the next three algorithms: logistic regression algorithm, decision trees and random forest. The results show that the decision tree algorithm had better performance with an AUC of 98%. Also, it was found the most common symptoms that a person with a risk of diabetes presents are polyuria, polydipsia and sudden weight loss.

scholarly journals Estimation of the parameters of fish stock dynamics from catch-at-age data and indices of abundance: can natural and fishing mortality be separated?

2007 ◽  
Vol 64 (8) ◽  
pp. 1130-1142 ◽  
Author(s):  
Sondre Aanes ◽  
Steinar Engen ◽  
Bernt-Erik Sæther ◽  
Ronny Aanes
Keyword(s):  
Gadus Morhua ◽  
State Space Model ◽  
Population Projections ◽  
Quality Data ◽  
Fish Stock ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Absolute Size ◽  
Data Set ◽  
Long Time

Models for fluctuations in size of fish stocks must include parameters that describe expected dynamics, as well as stochastic influences. In addition, reliable population projections also require assessments about the uncertainties in estimates of vital parameters. Here we develop an age-structured model of population dynamics based on catch-at-age data and indices of abundance in which the natural and fishing mortality are separated in a Bayesian state–space model. Markov chain Monte Carlo methods are used to fit the model to the data. The model is fitted to a data set of 19 years for Northeast Arctic cod (Gadus morhua). By simulations of the fitted model we show that the model captures the dynamical pattern of natural mortality adequately, whereas the absolute size of natural mortality is difficult to estimate. Access to long time series of high-quality data are necessary for obtaining precise estimates of all the parameters in the model, but some parameters cannot be estimated without including some prior information. Nevertheless, our model demonstrates that temporal variability in natural mortality strongly affects perceived variability in stock sizes. Thus, using estimation procedures that neglect temporal fluctuations in natural mortality may therefore give biased estimates of fluctuations in fish stock sizes.

scholarly journals New genus of extinct Holocene gibbon associated with humans in Imperial China

Science ◽  
2018 ◽  
Vol 360 (6395) ◽  
pp. 1346-1349 ◽  
Author(s):  
Samuel T. Turvey ◽  
Kristoffer Bruun ◽  
Alejandra Ortiz ◽  
James Hansford ◽  
Songmei Hu ◽  
...  
Keyword(s):  
Fossil Record ◽  
New Genus ◽  
Multivariate Analyses ◽  
Biodiversity Loss ◽  
Morphometric Data ◽  
Anthropogenic Pressures ◽  
Imperial China ◽  
Historical Accounts ◽  
Extinct Genus

Although all extant apes are threatened with extinction, there is no evidence for human-caused extinctions of apes or other primates in postglacial continental ecosystems, despite intensive anthropogenic pressures associated with biodiversity loss for millennia in many regions. Here, we report a new, globally extinct genus and species of gibbon, Junzi imperialis, described from a partial cranium and mandible from a ~2200- to 2300-year-old tomb from Shaanxi, China. Junzi can be differentiated from extant hylobatid genera and the extinct Quaternary gibbon Bunopithecus by using univariate and multivariate analyses of craniodental morphometric data. Primates are poorly represented in the Chinese Quaternary fossil record, but historical accounts suggest that China may have contained an endemic ape radiation that has only recently disappeared.

I Belong, Therefore, I Give? The Impact of Sense of Belonging on Graduate Student Alumni Engagement

2020 ◽  
pp. 089976402097768
Author(s):  
Noah D. Drezner ◽  
Oren Pizmony-Levy
Keyword(s):  
Social Interactions ◽  
Sense Of Belonging ◽  
Multivariate Analyses ◽  
Original Data ◽  
Alumni Giving ◽  
Data Set ◽  
Administrative Records ◽  
Success In Higher Education ◽  
Alumni Engagement ◽  
The Impact

Although Sense of Belonging has long been an important construct in understanding student success in higher education, it has not been examined in the alumni context. In this article, we explore the association between graduate students’ Sense of Belonging and alumni engagement. We draw on an original data set ( n = 1,601) that combines administrative records on alumni giving and data from a 2017 survey. Using multivariate analyses, we show that alumni with a stronger Sense of Belonging are more likely to give to their alma mater and to hold pro-philanthropic attitudes. Furthermore, Sense of Belonging is positively associated with other forms of alumni engagement and participation, including volunteering. Our findings highlight the need to examine the link between unintentional social interactions and alumni engagement and giving.

scholarly journals Linear and geometric morphometrics as tools to resolve species circumscription in the Pseudolaelia vellozicola complex (Orchidaceae, Laeliinae)

2019 ◽  
Vol 152 (1) ◽  
pp. 53-67 ◽  
Author(s):  
Luiz Menini Neto ◽  
Cássio Van den Berg ◽  
Rafaela Campostrini Forzza
Keyword(s):  
Natural Populations ◽  
Distinct Species ◽  
Multivariate Methods ◽  
Brazilian Atlantic Forest ◽  
Morphometric Data ◽  
Elliptic Fourier Analysis ◽  
Linear Measurements ◽  
Species Circumscription ◽  
Eastern Brazil ◽  
Sufficient Magnitude

Background and aims – Pseudolaelia is a genus endemic to eastern Brazil, with 12 accepted species predominantly distributed across granitic inselbergs of the Brazilian Atlantic Forest. The aim of the present study was to distinguish between the very similar taxa P. aguadocensis, P. oliveirana, P. regentii and P. vellozicola, using morphometric data acquired as linear measurements and outlines capture with Elliptic Fourier Analysis (EFA) of the floral parts. Material and methods – We sampled 208 specimens from 11 natural populations of the above taxa. We measured 20 floral variables and for the EFA, and we extracted 24 shape variables from the Fourier coefficient matrices, which describe the outlines of the floral parts. In both cases the data were analyzed with multivariate methods (both ordination and clustering). Key results – We could not find morphological discontinuities with sufficient magnitude to consider P. aguadocensis, P. oliveirana and P. regentii as distinct species from P. vellozicola. Conclusions – We propose that P. vellozicola should be considered a polymorphic and widely distributed species, generally supported by both methods.

scholarly journals 3D Airway Reconstruction Using Visible Human Data Set and Human Casts with Comparison to Morphometric Data

2009 ◽  
Vol 292 (7) ◽  
pp. 1028-1044 ◽  
Author(s):  
Risa J. Robinson ◽  
Jackie Russo ◽  
Richard L. Doolittle
Keyword(s):  
Morphometric Data ◽  
Data Set ◽  
Human Data ◽  
Airway Reconstruction ◽  
Visible Human

scholarly journals ExaViz: a flexible framework to analyse, steer and interact with molecular dynamics simulations

2014 ◽  
Vol 169 ◽  
pp. 119-142 ◽  
Author(s):  
Matthieu Dreher ◽  
Jessica Prevoteau-Jonquet ◽  
Mikael Trellet ◽  
Marc Piuzzi ◽  
Marc Baaden ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular System ◽  
Data Set ◽  
System P ◽  
Alternative Approach ◽  
Long Time ◽  
Flexible Framework ◽  
Sheer Size ◽  
Dynamics Simulations

The amount of data generated by molecular dynamics simulations of large molecular assemblies and the sheer size and complexity of the systems studied call for new ways to analyse, steer and interact with such calculations. Traditionally, the analysis is performed off-line once the huge amount of simulation results have been saved to disks, thereby stressing the supercomputer I/O systems, and making it increasingly difficult to handle post-processing and analysis from the scientist's office. The ExaViz framework is an alternative approach developed to couple the simulation with analysis tools to process the data as close as possible to their source of creation, saving a reduced, more manageable and pre-processed data set to disk. ExaViz supports a large variety of analysis and steering scenarios. Our framework can be used for live sessions (simulations short enough to be fully followed by the user) as well as batch sessions (long-time batch executions). During interactive sessions, at runtime, the user can display plots from analysis, visualise the molecular system and steer the simulation with a haptic device. We also emphasise how a CAVE-like immersive environment could be used to leverage such simulations, offering a large display surface to view and intuitively navigate the molecular system.

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