scholarly journals Longitudinal Study of Stable Isotope Compositions of Maternal Milk and Implications for the Palaeo-Diet of Infants

2017 ◽  
Vol 29 (3-4) ◽  
pp. 131-139 ◽  
Author(s):  
E. Herrscher ◽  
G. Goude ◽  
L. Metz
Keyword(s):  
Stable Isotope ◽  
Young Children ◽  
Exploratory Study ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Maternal Milk ◽  
Carbon Isotope Ratios ◽  
Mother And Child ◽  
The Difference ◽  
The Impact

The classic interpretation of stable isotope data from young children in an archaeological context is based on the hypothesis that the nitrogen isotope ratios present in breast milk remain identical throughout the breastfeeding period. This exploratory study assesses the changes in the nitrogen and carbon isotope ratios in maternal milk and in the nails of the mother and child, with the aim to evaluate the impact of variations in the stable isotope ratios in maternal milk on the tissues of children, and consequently on the reconstruction of the palaeo-diet of young children. The results show that the isotopic composition of maternal milk diminishes in relation to the mother's tissues like nails and, by extrapolation, bones. The δ15N values of the milk vary little during the weeks of breastfeeding, but this is not the case for carbon, which varies considerably during the course of breastfeeding and weaning and does not seem to be linked to the mother's diet and/or to the height and weight of the child. The difference between the δ15N values recorded for the mother's and child's nails is less than 2‰, which is lower than the values often cited in bioarchaeological literature. In addition, the data from this study does not confirm the hypothesis of a significant increase in heavy isotopes in the nails of newborn babies in relation to those of their mother at childbirth.

scholarly journals The Development and Use of Isoscapes to Determine the Geographical Origin of Quercus spp. in the United States

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 862 ◽  
Author(s):  
Charles J. Watkinson ◽  
Peter Gasson ◽  
Gareth O. Rees ◽  
Markus Boner
Keyword(s):  
United States ◽  
Stable Isotope ◽  
Oxygen Isotope ◽  
Hydrogen Isotope ◽  
Isotope Ratios ◽  
The United States ◽  
Stable Isotope Ratios ◽  
Carbon Isotope Ratios ◽  
Oxygen Isotope Ratios ◽  
Hydrogen Isotope Ratios

The stable isotope ratios of oxygen, hydrogen, carbon and sulfur from extracted wood of 87 samples of oaks from the United States were analysed. Relationships with climate variables and the stable isotope ratios of the 69 training dataset samples were investigated to a monthly resolution using long-term monthly mean climate data from NASA and the University of East Anglia’s Climate Research Unit, in conjunction with forecast data for hydrogen and oxygen isotope ratios in precipitation. These relationships were used to construct model isoscapes for oxygen, hydrogen, carbon and sulfur for US oak with the aim of using them to forecast isotopic patterns in areas that were not sampled and predict values in samples not used to construct the models. The leading predictors for isoscape generation were oxygen isotope ratios in January precipitation for oak oxygen isotope ratios, hydrogen isotope ratios in July precipitation for oak hydrogen isotope ratios, water vapour in April for carbon isotope ratios, and reflected shortwave radiation in March in combination with sulfate concentration in May for oak sulfur isotopes. The generated isoscapes can be used to show regions an unknown sample may have originated from with a resolution dependent on the rarity of the stable isotope signature within the United States. The models were assessed using the data of 18 samples of georeferenced oak. The assessment found that 100% of oxygen, 94% of hydrogen, 78% of carbon, and 94% of sulfur isotope ratios in the 18 test dataset samples fell within two standard deviations of the isoscape models. Using the results of the isoscapes in combination found that there were 4/18 test samples which did not fall within two standard deviations of the four models, this is largely attributed to the lower predictive power of the carbon isoscape model in conjunction with high local variability in carbon isotope ratios in both the test and training data. The method by which this geographic origin method has been developed will be useful to combat illegal logging and to validate legal supply chains for the purpose of good practice due diligence.

Juvenile Justice Reform and the Difference it Makes: An Exploratory Study of the Impact of Policy Change on Detention Worker Attitudes

1994 ◽  
Vol 40 (1) ◽  
pp. 37-53 ◽  
Author(s):  
Gordon Bazemore ◽  
Todd J. Dicker ◽  
Ron Nyhan
Keyword(s):  
Policy Implementation ◽  
Exploratory Study ◽  
Juvenile Detention ◽  
Staff Attitudes ◽  
Policy And Practice ◽  
Punitive Attitudes ◽  
Worker Attitudes ◽  
The Difference ◽  
The Impact ◽  
Detention Facilities

Despite increasing interest in policy implementation and reform, few studies have examined the impact of criminal justice reforms on staff attitudes. This article compares several dimensions of staff attitudes in two similar juvenile detention facilities: one that has undergone significant reform in policy and practice governing staff/detainee interaction and one that has not. Based on survey data gathered from workers in both facilities in the fall of 1991 (N = 109), exploratory findings reveal significant differences between workers in the two facilities in punitive attitudes, but few differences in other attitudes. Implications for understanding both behavioral and cognitive impacts of reforms are discussed.

How ‘Best’ to Determine Trophic Levels in Archaeological Agricultural Communities

2017 ◽  
Author(s):  
Linda Reynard
Keyword(s):  
Stable Isotope ◽  
Trophic Level ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Trophic Levels ◽  
Bone Collagen ◽  
Carbon And Nitrogen ◽  
Agricultural Communities ◽  
Plant Remains ◽  
Isotope System

Stable isotope ratios of bone collagen have been used to determine trophic levels in diverse archaeological populations. The longest established and arguably most successful isotope system has been nitrogen, followed by carbon, and more recently hydrogen. These trophic level proxies rely on a predictable change in isotope ratio with each trophic level step; however, this requirement may not always be met, which can lead to difficulties in interpreting archaeological evidence. In agricultural communities, in particular, there are several possible complications to the interpretation of nitrogen and carbon isotopes. Recent approaches to overcome these limitations include better quantification and understanding of the influences on consumer isotope ratios; inclusion of evidence from plant remains; further investigation of apatite δ13C—collagen δ13C spacing in bones; measurement of carbon and nitrogen isotope ratios in individual amino acids, rather than collagen; and development of other stable isotope proxies for trophic level, such as hydrogen isotopes.

Stable isotopes of carbon and nitrogen in the study of avian and mammalian trophic ecology

2000 ◽  
Vol 78 (1) ◽  
pp. 1-27 ◽  
Author(s):  
Jeffrey F Kelly
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Trophic Ecology ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Food Chains ◽  
Stable Isotope Ratios ◽  
Carbon And Nitrogen

Differential fractionation of stable isotopes of carbon during photosynthesis causes C4 plants and C3 plants to have distinct carbon-isotope signatures. In addition, marine C3 plants have stable-isotope ratios of carbon that are intermediate between C4 and terrestrial C3 plants. The direct incorporation of the carbon-isotope ratio (13C/12C) of plants into consumers' tissues makes this ratio useful in studies of animal ecology. The heavy isotope of nitrogen (15N) is preferentially incorporated into the tissues of the consumer from the diet, which results in a systematic enrichment in nitrogen-isotope ratio (15N/14N) with each trophic level. Consequently, stable isotopes of nitrogen have been used primarily to assess position in food chains. The literature pertaining to the use of stable isotopes of carbon and nitrogen in animal trophic ecology was reviewed. Data from 102 studies that reported stable-isotope ratios of carbon and (or) nitrogen of wild birds and (or) mammals were compiled and analyzed relative to diet, latitude, body size, and habitat moisture. These analyses supported the predicted relationships among trophic groups. Carbon-isotope ratios differed among species that relied on C3, C4, and marine food chains. Likewise, nitrogen-isotope ratios were enriched in terrestrial carnivorous mammals relative to terrestrial herbivorous mammals. Also, marine carnivores that ate vertebrates had nitrogen-isotope ratios that were enriched over the ratios of those that ate invertebrates. Data from the literature also indicated that (i) the carbon-isotope ratio of carnivore bone collagen was inversely related to latitude, which was likely the result of an inverse relationship between the proportion of carbon in the food chain that was fixed by C4 plants and latitude; (ii) seabirds and marine mammals from northern oceans had higher nitrogen-isotope ratios than those from southern oceans; (iii) the nitrogen-isotope ratios of terrestrial mammals that used xeric habitats were higher than the ratios of those that used mesic habitats, indicating that water stress can have important effects on the nitrogen-isotope ratio; (iv) there was no relationship between body mass and nitrogen-isotope ratio for either bone collagen or muscle of carnivores; and (v) there was linear covariation between stable-isotope ratios of carbon and nitrogen in marine food chains (but not in terrestrial C3 or C4 food chains), which is likely a product of increases in carbon-isotope ratio with trophic level in marine food chains. Differences in stable-isotope composition among trophic groups were detected despite variation attributable to geographic location, climate, and analytical techniques, indicating that these effects are large and pervasive. Consequently, as knowledge of the distribution of stable isotopes of carbon and nitrogen increases, they will probably become an increasingly important tool in the study of avian and mammalian trophic ecology.

Biology and Management of Dogfish Sharks

2009 ◽  
Keyword(s):  
Stable Isotope ◽  
Pacific Ocean ◽  
Food Webs ◽  
Trophic Position ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Gulf Of Alaska ◽  
The North ◽  
Northeastern Pacific ◽  
The Mean

Abstract.—Spiny dogfish <em>Squalus acanthias </em>biomass has increased in the Gulf of Alaska, yet little is known about the ecological niche that dogfish fill in this ecosystem. Trophic position is an important indicator of the ecological role of an organism. To explore the trophic position of dogfish we analyzed the nitrogen and carbon stable isotope ratios of 60 dogfish from five locations between Washington and the Gulf of Alaska. The mean δ<sup>15</sup>N values for dogfish ranged from 12.0‰ (central Gulf of Alaska) to 13.4‰ (Howe Sound, British Columbia) and the mean δ<sup>13</sup>C values ranged from –21.3‰ (Yakutat Bay, Alaska) to –17.9‰ (Puget Sound, Washington). Sites to the north tended to be significantly depleted in the heavy isotopes of both nitrogen and carbon. The differences in nitrogen isotope ratios among sites were attributed to potential changes in dogfish feeding behavior and trophic position. Differences in carbon isotope ratios suggested that dogfish utilize different food webs along the northeastern Pacific Ocean shelf. Additionally it was hypothesized that feeding differentially in offshore versus inshore food webs or targeting pelagic versus benthic prey species may explain the isotopic variability. These results are preliminary and require additional tests before conclusions can be made about the trophic position of dogfish in this region. Future work will explore stable isotope variability at lower trophic levels to test the hypothesis that entire food webs are isotopically shifted owing to differences in isotopic fractionation at the base of the food web. Also, trophic level differences among dogfish size classes and between sexes will be explored among a greater diversity of locations to better describe the ecological consequences of increased biomass of dogfish in the northeastern Pacific Ocean.

Stable-isotope and electron-microscopic evidence that cyamids (Crustacea: Amphipoda) feed on whale skin

2000 ◽  
Vol 78 (5) ◽  
pp. 721-727 ◽  
Author(s):  
Donald M Schell ◽  
Victoria J Rowntree ◽  
Carl J Pfeiffer
Keyword(s):  
Stable Isotope ◽  
Food Source ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Observational Evidence ◽  
Food Sources ◽  
Stable Carbon ◽  
Electron Microscopic ◽  
Carbon And Nitrogen ◽  
Trophic Enrichment

Cyamids (Crustacea: Amphipoda) are found only on whales. Observational evidence and the morphology of the mouthparts have indicated that whale skin is the primary food for these organisms. It has also been suggested, however, that the cyamids may be feeding on epidermal diatoms and meiofauna associated with the skin or using the whales as transport to regions of high zooplankton densities, where small pelagic organisms are captured while the whales feed. Here we report electron-microscopic and isotopic evidence that whale skin was ingested and assimilated by cyamids. Stable carbon and nitrogen isotope ratios of cyamids and whale skin from six species of whales were compared with those of zooplankton from the regions through which the whales migrate, to infer the most likely food sources. In all cases, cyamid isotope ratios closely matched those of the whale skin and not those of the zooplankton, again indicating that whale skin was the predominant food source. Unlike most other carnivorous organisms, cyamids do not show a trophic enrichment of δ15N, a trait also found in other species of Amphipoda.

Children's Earliest Memories: A Narrative Study

2002 ◽  
Vol 27 (4) ◽  
pp. 1-5
Author(s):  
Anne E. Grey
Keyword(s):  
Young Children ◽  
Autobiographical Memory ◽  
Exploratory Study ◽  
Learning And Teaching ◽  
Narrative Study ◽  
Narrative Ability ◽  
The Impact

This article explores the concept of children's autobiographical memory that is evident from the age of four onwards. Recent findings on the construction of memories, the development of narrative ability and the impact of culture on memory are discussed in relation to an exploratory study of children's earliest memories. Although no conclusion could be made as to whether children's memories are co-constructed or spontaneous, findings show that earliest memories were of atypical events that had occurred in the child's life. Implications for learning and teaching of young children are included.

scholarly journals Spatial and Temporal Variability of Ice Algal Trophic Markers—With Recommendations about Their Application

2020 ◽  
Vol 8 (9) ◽  
pp. 676
Author(s):  
Eva Leu ◽  
Thomas A. Brown ◽  
Martin Graeve ◽  
Jozef Wiktor ◽  
Clara J. M. Hoppe ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Sea Ice ◽  
Temporal Variability ◽  
Climate Change Impacts ◽  
Isotope Ratios ◽  
Arctic Sea Ice ◽  
Stable Isotope Ratios ◽  
Spatial And Temporal Variability ◽  
Web Studies ◽  
The Impact

Assessing the relative importance of sea ice algal-based production is often vital for studies about climate change impacts on Arctic marine ecosystems. Several types of lipid biomarkers and stable isotope ratios are widely used for tracing sea ic-associated (sympagic) vs. pelagic particulate organic matter (POM) in marine food webs. However, there has been limited understanding about the plasticity of these compounds in space and time, which constrains the robustness of some of those approaches. Furthermore, some of the markers are compromised by not being unambiguously specific for sea ice algae, whereas others might only be produced by a small sub-group of species. We analyzed fatty acids, highly branched isoprenoids (HBIs), stable isotope ratios of particulate organic carbon (POC) (δ13C), as well as δ13C of selected fatty acid markers during an Arctic sea ice algal bloom, focusing on spatial and temporal variability. We found remarkable differences between these approaches and show that inferences about bloom characteristics might even be contradictory between markers. The impact of environmental factors as causes of this considerable variability is highlighted and explained. We emphasize that awareness and, in some cases, caution is required when using lipid and stable isotope markers as tracers in food web studies and offer recommendations for the proper application of these valuable approaches.

Climate and Habitat Reconstruction Using Stable Carbon and Nitrogen Isotope Ratios of Collagen in Prehistoric Herbivore Teeth from Kenya

1989 ◽  
Vol 31 (3) ◽  
pp. 407-422 ◽  
Author(s):  
Stanley H. Ambrose ◽  
Michael J. DeNiro
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Analytical Methods ◽  
Rift Valley ◽  
Isotope Analysis ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Habitat Conditions ◽  
Stable Carbon ◽  
Carbon And Nitrogen

AbstractStable carbon and nitrogen isotope ratios have been determined for tooth collagen of 27 prehistoric herbivores from a rock shelter in the central Rift Valley of Kenya. Collagen samples whose isotope ratios were not altered by diagenesis were identified using several analytical methods. During the later Holocene, when the climate was as dry or drier than at present, the isotopic compositions of individual animals are similar to those of modern individuals of the same species. During the earlier Holocene, when the climate was wetter than at present, the δ15N and δ13C values are lower than those for their modern counterparts. When diagenetic factors can be discounted and adequate modern comparative data are available, stable isotope analysis of herbivore teeth and bones can be used to evaluate prehistoric climate and habitat conditions.

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