scholarly journals The tooth, the whole tooth and nothing but the tooth: tooth shape and ontogenetic shift dynamics in the white sharkCarcharodon carcharias

2017 ◽  
Vol 91 (4) ◽  
pp. 1032-1047 ◽  
Author(s):  
G. C. A. French ◽  
M. Stürup ◽  
S. Rizzuto ◽  
J. H. van Wyk ◽  
D. Edwards ◽  
...  
Keyword(s):  
Ontogenetic Shift ◽  
Tooth Shape ◽  
Shift Dynamics

scholarly journals Influence of Various Tooth Shape Topology for Single-Phase Permanent Magnet Flux Switching Machine

2021 ◽  
Vol 1127 (1) ◽  
pp. 012027
Author(s):  
Laili Iwani Jusoh ◽  
Erwan Sulaiman ◽  
Md Zarafi Ahmad ◽  
Irfan Ali Soomro ◽  
Hassan Ali Soomro
Keyword(s):  
Permanent Magnet ◽  
Single Phase ◽  
Tooth Shape

scholarly journals Quantifying Southern Pacific Rattlesnake (Crotalus oreganus helleri) Hunting Behavior through Community Science

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 349
Author(s):  
Emily R. Urquidi ◽  
Breanna J. Putman
Keyword(s):  
Habitat Loss ◽  
Human Activity ◽  
Age Differences ◽  
Environmental Changes ◽  
Microhabitat Use ◽  
Ontogenetic Shift ◽  
Community Members ◽  
Hunting Behavior ◽  
Crotalus Oreganus ◽  
Community Science

It is increasingly important to study animal behaviors as these are the first responses organisms mount against environmental changes. Rattlesnakes, in particular, are threatened by habitat loss and human activity, and require costly tracking by researchers to quantify the behaviors of wild individuals. Here, we show how photo-vouchered observations submitted by community members can be used to study cryptic predators like rattlesnakes. We utilized two platforms, iNaturalist and HerpMapper, to study the hunting behaviors of wild Southern Pacific Rattlesnakes. From 220 observation photos, we quantified the direction of the hunting coil (i.e., “handedness”), microhabitat use, timing of observations, and age of the snake. With these data, we looked at whether snakes exhibited an ontogenetic shift in behaviors. We found no age differences in coil direction. However, there was a difference in the microhabitats used by juveniles and adults while hunting. We also found that juveniles were most commonly observed during the spring, while adults were more consistently observed throughout the year. Overall, our study shows the potential of using community science to study the behaviors of cryptic predators.

scholarly journals Ontogenetic shift in the scaling of dark respiration with whole-plant mass in seven shrub species

2009 ◽  
Vol 24 (3) ◽  
pp. 502-512 ◽  
Author(s):  
Youhong Peng ◽  
Karl J. Niklas ◽  
Peter B. Reich ◽  
Shucun Sun
Keyword(s):  
Dark Respiration ◽  
Ontogenetic Shift ◽  
Shrub Species ◽  
Whole Plant

Planar Procrustes analysis of tooth shape

2001 ◽  
Vol 46 (3) ◽  
pp. 191-199 ◽  
Author(s):  
D.L Robinson ◽  
P.G Blackwell ◽  
E.C Stillman ◽  
A.H Brook
Keyword(s):  
Procrustes Analysis ◽  
Tooth Shape

scholarly journals Language shift, bilingualism and the future of Britain's Celtic languages

2010 ◽  
Vol 365 (1559) ◽  
pp. 3855-3864 ◽  
Author(s):  
Anne Kandler ◽  
Roman Unger ◽  
James Steele
Keyword(s):  
Census Data ◽  
Language Shift ◽  
Past Century ◽  
Transitional State ◽  
Endangered Language ◽  
Basic Model ◽  
Vernacular Language ◽  
Celtic Languages ◽  
Shift Dynamics ◽  
Demographic Trajectories

‘Language shift’ is the process whereby members of a community in which more than one language is spoken abandon their original vernacular language in favour of another. The historical shifts to English by Celtic language speakers of Britain and Ireland are particularly well-studied examples for which good census data exist for the most recent 100–120 years in many areas where Celtic languages were once the prevailing vernaculars. We model the dynamics of language shift as a competition process in which the numbers of speakers of each language (both monolingual and bilingual) vary as a function both of internal recruitment (as the net outcome of birth, death, immigration and emigration rates of native speakers), and of gains and losses owing to language shift. We examine two models: a basic model in which bilingualism is simply the transitional state for households moving between alternative monolingual states, and a diglossia model in which there is an additional demand for the endangered language as the preferred medium of communication in some restricted sociolinguistic domain, superimposed on the basic shift dynamics. Fitting our models to census data, we successfully reproduce the demographic trajectories of both languages over the past century. We estimate the rates of recruitment of new Scottish Gaelic speakers that would be required each year (for instance, through school education) to counteract the ‘natural wastage’ as households with one or more Gaelic speakers fail to transmit the language to the next generation informally, for different rates of loss during informal intergenerational transmission.

Influence of phylogeny on the estimation of diet from dental morphology in the Carnivora

Paleobiology ◽  
2021 ◽  
pp. 1-16
Author(s):  
Samantha S. B. Hopkins ◽  
Samantha A. Price ◽  
Alec J. Chiono
Keyword(s):  
Evolutionary History ◽  
Morphological Data ◽  
Evolutionary Constraints ◽  
Dental Morphology ◽  
Tooth Shape ◽  
Fossil Mammals ◽  
Phylogenetic Constraints ◽  
Substantial Error ◽  
Evolutionary Tempo And Mode ◽  
Vertebrate Skeleton

Abstract Because teeth are the most easily preserved part of the vertebrate skeleton and are particularly morphologically variable in mammals, studies of fossil mammals rely heavily on dental morphology. Dental morphology is used both for systematics and phylogeny as well as for inferences about paleoecology, diet in particular. We analyze the influence of evolutionary history on our ability to reconstruct diet from dental morphology in the mammalian order Carnivora, and we find that much of our understanding of diet in carnivorans is dependent on the phylogenetic constraints on diet in this clade. Substantial error in estimating diet from dental morphology is present regardless of the morphological data used to make the inference, although more extensive morphological datasets are more accurate in predicting diet than more limited character sets. Unfortunately, including phylogeny in making dietary inferences actually decreases the accuracy of these predictions, showing that dietary predictions from morphology are substantially dependent on the evolutionary constraints on carnivore diet and tooth shape. The “evolutionary ratchet” that drives lineages of carnivorans to evolve greater degrees of hypercarnivory through time actually plays a role in allowing dietary inference from tooth shape, but consequently requires caution in interpreting dietary inference from the teeth fossil carnivores. These difficulties are another reminder of the differences in evolutionary tempo and mode between morphology and ecology.

An Improved Fuse Escapement for the Mark 18 and Other U. S. Navy Mechanical Time Fuses

1946 ◽  
Vol 13 (4) ◽  
pp. A285-A290
Author(s):  
F. G. Kelly ◽  
J. L. Zar
Keyword(s):  
Test Performance ◽  
Neutral Position ◽  
Matching Function ◽  
Tooth Shape ◽  
Firing Test ◽  
Driving Torque

Abstract Theoretical shortcomings of previous Army and Navy fuse escapements are pointed out. The development of a new escape wheel and lever is described, in which spurious torques due to the fall of escape-wheel teeth against the pallets are eliminated; and a tooth shape is derived which delivers accelerating impulses symmetrically about the neutral position of the lever. Fuses with the new escapement have a timing rate which is independent of driving torque over the range of torques encountered; they can be assembled with one size of wheel and lever and with no hand-matching, function at low driving torques, and have given improved firing-test performance.

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