scholarly journals Magnesium stable isotope ecology using mammal tooth enamel

2014 ◽  
Vol 112 (2) ◽  
pp. 430-435 ◽  
Author(s):  
Jeremy E. Martin ◽  
Derek Vance ◽  
Vincent Balter
Keyword(s):  
Tooth Enamel ◽  
Isotope Ratios ◽  
Trophic Chain ◽  
Mammal Species ◽  
Elemental Ratios ◽  
Limited Sampling ◽  
Equatorial Africa ◽  
Recent Developments ◽  
Using Data ◽  
Paleodietary Reconstruction

Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this26Mg enrichment up the trophic chain is due to a26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

scholarly journals Emerging issues in genomic selection

2021 ◽  
Author(s):  
I Misztal ◽  
I Aguilar ◽  
D Lourenco ◽  
L Ma ◽  
J Steibel ◽  
...  
Keyword(s):  
Genomic Selection ◽  
Sparse Matrices ◽  
Large Datasets ◽  
Single Step ◽  
Genomic Information ◽  
Long Term Effects ◽  
Additive Variance ◽  
Recent Developments ◽  
Emerging Issues ◽  
Using Data

Abstract Genomic selection is now practiced successfully across many species. However, many questions remain such as long-term effects, estimations of genomic parameters, robustness of GWAS with small and large datasets, and stability of genomic predictions. This study summarizes presentations from at the 2020 ASAS symposium. The focus of many studies until now is on linkage disequilibrium (LD) between two loci. Ignoring higher level equilibrium may lead to phantom dominance and epistasis. The Bulmer effect leads to a reduction of the additive variance; however, selection for increased recombination rate can release anew genetic variance. With genomic information, estimates of genetic parameters may be biased by genomic preselection, but costs of estimation can increase drastically due to the dense form of the genomic information. To make computation of estimates feasible, genotypes could be retained only for the most important animals, and methods of estimation should use algorithms that can recognize dense blocks in sparse matrices. GWAS studies using small genomic datasets frequently find many marker-trait associations whereas studies using much bigger datasets find only a few. Most current tools use very simple models for GWAS, possibly causing artifacts. These models are adequate for large datasets where pseudo-phenotypes such as deregressed proofs indirectly account for important effects for traits of interest. Artifacts arising in GWAS with small datasets can be minimized by using data from all animals (whether genotyped or not), realistic models, and methods that account for population structure. Recent developments permit computation of p-values from GBLUP, where models can be arbitrarily complex but restricted to genotyped animals only, and to single-step GBLUP that also uses phenotypes from ungenotyped animals. Stability was an important part of nongenomic evaluations, where genetic predictions were stable in the absence of new data even with low prediction accuracies. Unfortunately, genomic evaluations for such animals change because all animals with genotypes are connected. A top ranked animal can easily drop in the next evaluation, causing a crisis of confidence in genomic evaluations. While correlations between consecutive genomic evaluations are high, outliers can have differences as high as one SD. A solution to fluctuating genomic evaluations is to base selection decisions on groups of animals. While many issues in genomic selection have been solved, many new issues that require additional research continue to surface.

Maximization of the Signal Impulsiveness Combining Envelope Technique with Minimum Entropy Deconvolution

2013 ◽  
Vol 392 ◽  
pp. 725-729 ◽  
Author(s):  
Rafael José Gomes de Oliveira ◽  
Mauro Hugo Mathias
Keyword(s):  
Test Bench ◽  
Minimum Entropy ◽  
Combined Application ◽  
Recent Developments ◽  
Gear Trains ◽  
The Subject ◽  
Using Data ◽  
High Frequency Resonance ◽  
Combined Technique ◽  
Experimental Test Bench

The application of the HFRT (High-Frequency Resonance Technique), a demodulation based technique, is a technique for evaluation the condition of bearings and other components in rotating machinery. Another technique MED (Minimum Entropy Deconvolution) has been the subject of recent developments for application in condition monitoring of gear trains and roller bearings. This article demonstrates the effectiveness of the combined application of the MED technique with HFRT in order to enhance the capacity of HFRT to identify the characteristic fault frequencies of damaged bearings by increasing the signal impulsivity. All tests were done using data collected from an experimental test bench in laboratory. The Kurtosis value is used as an indicator of effectiveness of the combined technique and the results shown an increase of five times the original kurtosis value with the application of MED filter together with the HFRT.

scholarly journals Radiocarbon Dating of Calcined Bones: Where Does the Carbon Come from?

Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 601-611 ◽  
Author(s):  
A Zazzo ◽  
J-F Saliège ◽  
A Person ◽  
H Boucher
Keyword(s):  
Radiocarbon Dating ◽  
Tooth Enamel ◽  
Skeletal Remains ◽  
Archaeological Sites ◽  
Carbonate Content ◽  
The Past ◽  
Mineral Fraction ◽  
Different Temperatures ◽  
C Value ◽  
Paleodietary Reconstruction

Over the past decade, radiocarbon dating of the carbonate contained in the mineral fraction of calcined bones has emerged as a viable alternative to dating skeletal remains in situations where collagen is no longer present. However, anomalously low δ13C values have been reported for calcined bones, suggesting that the mineral fraction of bone is altered. Therefore, exchange with other sources of carbon during heating cannot be excluded. Here, we report new results from analyses on cremated bones found in archaeological sites in Africa and the Near East, as well as the results of several experiments aiming at improving our understanding of the fate of mineral and organic carbon of bone during heating. Heating of modern bone was carried out at different temperatures, for different durations, and under natural and controlled conditions, and the evolution of several parameters (weight, color, %C, %N, δ13C value, carbonate content, crystallinity indexes measured by XRD and FTIR) was monitored. Results from archaeological sites confirm that calcined bones are unreliable for paleoenvironmental and paleodietary reconstruction using stable isotopes. Experimental results suggest that the carbon remaining in bone after cremation likely comes from the original inorganic pool, highly fractionated due to rapid recrystallization. Therefore, its reliability for 14C dating should be seen as close to that of tooth enamel, due to crystallographic properties of calcined bones.

scholarly journals Magnetism Science with the Square Kilometre Array

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 53
Author(s):  
George Heald ◽  
Sui Mao ◽  
Valentina Vacca ◽  
Takuya Akahori ◽  
Ancor Damas-Segovia ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Dark Matter Annihilation ◽  
New Techniques ◽  
Square Kilometre Array ◽  
New Radio ◽  
Recent Developments ◽  
Using Data ◽  
The Impact

The Square Kilometre Array (SKA) will answer fundamental questions about the origin, evolution, properties, and influence of magnetic fields throughout the Universe. Magnetic fields can illuminate and influence phenomena as diverse as star formation, galactic dynamics, fast radio bursts, active galactic nuclei, large-scale structure, and dark matter annihilation. Preparations for the SKA are swiftly continuing worldwide, and the community is making tremendous observational progress in the field of cosmic magnetism using data from a powerful international suite of SKA pathfinder and precursor telescopes. In this contribution, we revisit community plans for magnetism research using the SKA, in light of these recent rapid developments. We focus in particular on the impact that new radio telescope instrumentation is generating, thus advancing our understanding of key SKA magnetism science areas, as well as the new techniques that are required for processing and interpreting the data. We discuss these recent developments in the context of the ultimate scientific goals for the SKA era.

Hadrosaurid migration: inferences based on stable isotope comparisons among Late Cretaceous dinosaur localities

Paleobiology ◽  
2009 ◽  
Vol 35 (2) ◽  
pp. 270-288 ◽  
Author(s):  
Henry C. Fricke ◽  
Raymond R. Rogers ◽  
Terry A. Gates
Keyword(s):  
Oxygen Isotope ◽  
Late Cretaceous ◽  
Tooth Enamel ◽  
Isotope Ratios ◽  
Isotopic Signatures ◽  
Oxygen Isotope Ratios ◽  
Drinking Waters ◽  
Carbon And Oxygen Isotope ◽  
Western Interior Basin ◽  
Major Alteration

Stable carbon and oxygen isotope ratios were measured for carbonate in samples of hadrosaurid tooth enamel and dentine, and gar scale ganoine and dentine from five geologically “contemporaneous“ (two-million-year resolution) and geographically distant late Campanian formations (Two Medicine, Dinosaur Park, Judith River, Kaiparowits, and Fruitland) in the Western Interior Basin. In all cases, isotopic offsets were observed between enamel and dentine from the same teeth, with dentine being characterized by higher and more variable carbon and oxygen isotope ratios. Isotopic offsets were also observed between gar ganoine and hadrosaur enamel in all sites analyzed. Both of these observations indicate that diagenetic overprinting of enamel isotope ratios did not entirely obfuscate primary signals. Decreases in carbon and oxygen isotope ratios were observed in hadrosaur enamel from east to west, and overlap in isotope ratios occurred only between two of the sampled sites (Dinosaur Park and Judith River Formations).The lack of isotopic overlap for enamel among localities could be due to diagenetic resetting of isotope ratios such that they reflect local groundwater effects rather than primary biogenic inputs. However, the large range in carbon isotope ratios, the consistent taxonomic offsets for enamel/ganoine data, and comparisons of enamel-dentine data from the same teeth all suggest that diagenesis is not the lone driver of the signal. In the absence of major alteration, the mostly likely explanation for the isotopic patterns observed is that hadrosaurids from the targeted formations were eating plants and drinking waters with distinct isotopic ratios. One implication of this reconstruction is that hadrosaurids in the Late Cretaceous of the Western Interior did not migrate to an extent that would obscure local isotopic signatures.

scholarly journals Party membership, pre-parliamentary socialization and party cohesion

2021 ◽  
pp. 135406882110390
Author(s):  
Jochen Rehmert
Keyword(s):  
Social Identity Theory ◽  
Voting Behavior ◽  
Party Membership ◽  
Political Careers ◽  
Recent Developments ◽  
Party Cohesion ◽  
Using Data ◽  
German Bundestag ◽  
Established Democracies

Party membership seems to lose relevance for political careers in many established democracies. Increasing numbers of parties are recruiting non-members as candidates. Yet, what are the implications of a lack of long-term party membership for party cohesion? In this paper, I argue that pre-parliamentary party membership is in fact crucial for cohesion. Using data from the Comparative Candidate Survey and voting behavior of ca. 2,000 MPs of the German Bundestag on free votes from 1953 to 2013, I examine the effect of length of previous party membership and the age of joining the party on indicators of party cohesion. Examining free votes allows for credibly controlling alternative explanations of unified voting behavior. Results are in line with expectations generated from social identity theory and underscore the importance of party membership for party cohesion. The paper concludes with a discussion on the findings’ implications in light of recent developments in parties’ candidate recruitment.

Stable isotope evidence for changes in dietary niche partitioning among hadrosaurian and ceratopsian dinosaurs of the Hell Creek Formation, North Dakota

Paleobiology ◽  
2008 ◽  
Vol 34 (4) ◽  
pp. 534-552 ◽  
Author(s):  
Henry C. Fricke ◽  
Dean A. Pearson
Keyword(s):  
Stable Isotope ◽  
Oxygen Isotope ◽  
Tooth Enamel ◽  
Habitat Preferences ◽  
Niche Partitioning ◽  
Isotope Ratios ◽  
Oxygen Isotope Ratios ◽  
Carbon And Oxygen Isotope ◽  
Dietary Niche ◽  
Ceratopsian Dinosaurs

Questions related to dinosaur behavior can be difficult to answer conclusively by using morphological studies alone. As a complement to these approaches, carbon and oxygen isotope ratios of tooth enamel can provide insight into habitat and dietary preferences of herbivorous dinosaurs. This approach is based on the isotopic variability in plant material and in surface waters of the past, which is in turn reflected by carbon and oxygen isotope ratios of animals that ingested the organic matter or drank the water. Thus, it has the potential to identify and characterize dietary and habitat preferences for coexisting taxa.In this study, stable isotope ratios from coexisting hadrosaurian and ceratopsian dinosaurs of the Hell Creek Formation of North Dakota are compared for four different stratigraphic levels. Isotopic offsets between tooth enamel and tooth dentine, as well as taxonomic differences in means and in patterns of isotopic data among taxa, indicate that primary paleoecological information is preserved. The existence of taxonomic offsets also provides the first direct evidence for dietary niche partitioning among these herbivorous dinosaur taxa. Of particular interest is the observation that the nature of this partitioning changes over time: for some localities ceratopsian dinosaurs have higher carbon and oxygen isotope ratios than hadrosaurs, indicating a preference for plants living in open settings near the coast, whereas for other localities isotope ratios are lower, indicating a preference for plants in the understory of forests. In most cases the isotope ratios among hadrosaurs are similar and are interpreted to represent a dietary preference for plants of the forest canopy. The inferred differences in ceratopsian behavior are suggested to represent a change in vegetation cover and hence habitat availability in response to sea level change or to the position of river distributaries. Given our current lack of taxonomic resolution, it is not possible to determine if dietary and habitat preferences inferred from stable isotope data are associated with single, or multiple, species of hadrosaurian/ceratopsian dinosaurs.

Carbon isotope ratios of human tooth enamel record the evidence of terrestrial resource consumption during the Jomon period, Japan

2015 ◽  
Vol 158 (2) ◽  
pp. 300-311 ◽  
Author(s):  
Soichiro Kusaka ◽  
Kevin T. Uno ◽  
Takanori Nakano ◽  
Masato Nakatsukasa ◽  
Thure E. Cerling
Keyword(s):  
Carbon Isotope ◽  
Tooth Enamel ◽  
Isotope Ratios ◽  
Resource Consumption ◽  
Human Tooth ◽  
Carbon Isotope Ratios ◽  
Human Tooth Enamel

scholarly journals Estudio preliminar de la fauna en el morro de basuras de Moravia y presencia de metales pesados en artrópodos y roedores

2010 ◽  
Vol 15 (1) ◽  
pp. 49 ◽  
Author(s):  
María Solange Sánchez ◽  
Alejandra Bedoya ◽  
Rolando Barahona
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Mus Musculus ◽  
Atomic Spectroscopy ◽  
Trophic Chain ◽  
Metal Analysis ◽  
Mammal Species ◽  
Tissue Samples ◽  
Heavy Metal Analysis

<p><strong></strong>Characterization of the species present in a given locality by means of biological inventories provides information about diversity, even if it is done in disturbed environments such as open dumps, which are considered a threat for health due to the accumulation of heavy metals that are well known for their negative effects on human health and the environment. <strong>Objectives</strong>. To carry out a preliminary characterization of arthropods and non-flying small mammals in the <em>Morro de Moravia</em> open dump, and to determine the heavy metal contents in animal tissue samples. <strong>Materials and Methods. </strong>Arthropods were collected with pitfall traps and manually. Rodents were captured with Sherman traps. The heavy metal analysis was carried out with atomic spectroscopy. <strong>Results</strong>. A total of 9 orders, 51 families and 75 morphospecies of insects, 5 families of spiders, two syrphid and a millipede species were identified; <em>Mus musculus</em> was the only small mammal species identified. Heavy metal analysis showed various concentrations mainly of Pb and Cd. The highest content of Pb (45.05 mg/kg) was found in samples of <em>M. musculus</em> and the highest Cd content (10.31 mg/kg) was found in spiders of the family Gasteracantha. <strong>Conclusions</strong>. The <em>Morro de Moravia</em> open dump provides conditions that allow the establishment of an arthropod community with various diets and niches. The transference of heavy metals from the residue matrix towards higher levels of the trophic chain was corroborated.</p> <p><strong>Key words:</strong> arthropods, biological inventories, cadmium, <em>Mus musculus, </em>lead</p><br />

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