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1.
Food Chem ; 338: 127924, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32932079

RESUMO

An exploratory study for verifying regional geographical origin of carrots from specific production regions in Austria ("Genussregionen") was performed by combining chemical fingerprinting methods, namely n(86Sr)/n(87Sr) isotope amount ratios, multi-elemental and metabolomic pattern. Chemometric classification models were built on individual and combined datasets using (data-driven) soft independent modelling of class analogies and (orthogonal) projections to latent structures-discriminant analysis to characterise and differentiate carrots grown in five regions in Austria. A predictive ability of 97% or better (depending on the classification technique) was obtained using combined Sr isotope amount ratios and multi-elemental data. The use of data fusion strategies, in particular the mid-level option (fusion of selected variables from the different analytical platforms), allowed highly efficient (99-100%, except soft independent modelling of class analogy with 97%) and correct classification of carrot samples.


Assuntos
Daucus carota/metabolismo , Metaboloma , Metabolômica/métodos , Isótopos de Estrôncio/análise , Áustria , Boro/análise , Daucus carota/química , Análise Discriminante , Geografia , Análise dos Mínimos Quadrados , Magnésio/análise , Análise de Componente Principal , Isótopos de Estrôncio/metabolismo
2.
Rapid Commun Mass Spectrom ; 35(6): e9031, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33336436

RESUMO

RATIONALE: Identifying migratory corridors of animals is essential for their effective protection, yet the exact location of such corridors is often unknown, particularly for elusive animals such as bats. While migrating along the German coastline, Nathusius' pipistrelles (Pipistrellus nathusii) are regularly killed at wind turbines. Therefore, we explored the paths taken on their annual journey. METHODS: We used isotope ratio mass spectrometry to measure stable hydrogen and strontium isotope ratios in fur keratin of 59 Nathusius' pipistrelles captured on three offshore islands. Samples were pre-treated before analysis to report exclusively stable isotope ratios of non-exchangeable hydrogen. We generated maps to predict summer origins of bats using isoscape models. RESULTS: Bats were classified as long-distance migrants, mostly originating from Eastern Europe. Hydrogen analysis suggested for some bats a possible Fennoscandian origin, yet additional information from strontium analysis excluded this possibility. Instead, our data suggest that most Nathusius' pipistrelles migrating along the German coastline were of continental European summer origin, but also highlight the possibility that Nathusius' pipistrelles of Baltorussian origin may travel offshore from Fennoscandia to Germany. CONCLUSIONS: Our findings demonstrate the benefit of using complementary isotopic tracers for analysing the migratory pathways of bats and also potentially other terrestrial vertebrate species. Furthermore, data from our study suggest an offset of fur strontium isotope ratios in relation to local bedrock.


Assuntos
Pelo Animal/química , Quirópteros/classificação , Deutério/análise , Isótopos de Estrôncio/análise , Pelo Animal/metabolismo , Migração Animal , Animais , Quirópteros/fisiologia , Deutério/metabolismo , Europa (Continente) , Estações do Ano , Isótopos de Estrôncio/metabolismo
3.
Chemosphere ; 260: 127559, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673872

RESUMO

Bacillus pumilus SWU7-1 was isolated from strontium ion (Sr(II))-uncontaminated soil, its biosorption potential was evaluated, and the effect of γ-ray radiation treatment on its biosorption was discussed. Domesticated under Sr(II) stress promoted the biosorption ability of B. pumilus to Sr(II), and the biosorption efficiency increased from 46.09% to 94.69%. At a lower initial concentration, the living bacteria had the ability to resist the biosorption of Sr(II). The optimal initial concentration range was 54-130 mg/L. The biosorption profile was better matched by Langmuir than Freundlich model, showing that the biosorption process of Sr(II) by the experimental strain was closer to the surface adsorption. According to Langmuir model, the maximum biosorption capacity of B. pumilus on Sr (II) was 299.4 mg/g. During the bacterial growth in the biosorption process, the changes in biosorption capacity and efficiency can be divided into two phases, and a pseudo-second-order model is followed in each phase. There was no significant difference in the biosorption efficiency of bacteria with different culture time after γ-ray radiation, and all of them were above 90%, which showed that B. pumilus had significant radiation resistance under experimental conditions. This study emphasized the potential application of B. pumilus in the treatment of radioactive Sr(II) pollution by biosorption.


Assuntos
Adsorção , Bacillus pumilus/metabolismo , Biodegradação Ambiental , Isótopos de Estrôncio/metabolismo , Cinética , Microbiologia do Solo , Poluentes Radioativos do Solo , Poluentes Químicos da Água/metabolismo
4.
J Sci Food Agric ; 100(9): 3666-3674, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32246459

RESUMO

BACKGROUND: Apples have a leading role in the Italian fruit sector, and high-quality apples, including the Golden Delicious variety, are cultivated mainly in the Northern mountain districts. In the present study, Golden Delicious apples from PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) cultivation districts were characterized according to their Sr isotope composition and compared with apples from other Northern Italian districts. RESULTS: Apples collected in two consecutive years (2017 and 2018) confirmed the low annual variability of the 87 Sr/86 Sr ratio. The isotope ratio of apples was highly correlated with that of the soil extracts of the respective orchards. Statistical differences were highlighted between cultivation districts. However, because similar geological features characterized some areas, their ratios overlapped and a complete separation of the districts was not possible. CONCLUSION: The 87 Sr/86 Sr ratio is an excellent marker for studies of food traceability because it retains the information about the place of origin. However, its strength is limited when comparing products from cultivation areas sharing similar geological features. In the perspective of geographical traceability, a multichemical characterization can overcome the limits of single-parameter approach. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Malus/química , Solo/química , Isótopos de Estrôncio/análise , Agricultura , Frutas/química , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Itália , Malus/crescimento & desenvolvimento , Malus/metabolismo , Isótopos de Estrôncio/metabolismo
5.
Am J Phys Anthropol ; 170(4): 551-564, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31633810

RESUMO

OBJECTIVES: Riparian or gallery forests are critical habitats for numerous plants and animals today. Paleoanthropologically, reliance on such habitats informs behavioral and ecological reconstructions; for example, gallery forest habitats likely played a critical role in the transition from ape to hominin in the early Pliocene and may represent a preferred habitat for the last common ancestor of chimpanzees and humans. Direct indicators for gallery forest habitats preference are lacking. The objective of this article is to assess whether strontium isotope ratios are a reliable indicator of habitat preference for fauna living in and around gallery forests. MATERIALS AND METHODS: We report bioavailable strontium isotope ratios from the Mugiri River, its tributaries, and its gallery forest (Toro-Semliki Wildlife Reserve, southwestern Uganda), and compare them to surrounding savanna-grassland values. We compare these environmental values to strontium isotopes ratios in faunal tooth enamel to determine if habitat preferences are accurately reflected. RESULTS: Gallery forest and savanna-grassland vegetations have significantly different strontium isotope ratio profiles. We trace these isotopic differences to the influence of the Mugiri tributaries, which originate on Paleoproterozoic gneiss deposits on top of the surrounding escarpments. These isotopic differences in vegetation are mirrored in the tissues of fauna with habitat preferences for either the gallery forest or the surrounding grasslands. DISCUSSION: This research demonstrates the potential of strontium isotope ratios to identify habitat preferences in modern or fossil fauna under proper geologic variability. It provides a methodological model for future studies seeking to reconstruct habitat preferences in early hominins.


Assuntos
Distribuição Animal , Antropologia/métodos , Evolução Biológica , Florestas , Pradaria , Pan troglodytes , Isótopos de Estrôncio/análise , Animais , Disponibilidade Biológica , Osso e Ossos/química , Humanos , Mamíferos , Plantas/química , Rios/química , Isótopos de Estrôncio/metabolismo , Uganda
6.
Sci Total Environ ; 653: 1458-1512, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30759584

RESUMO

Radiostrontium is released to the environment from routine and accidental discharge and acts on living organisms either from external sources or after absorption. When incorporated by plants, it enters the food chain and causes primary threat to human health and the environment. Understanding the mechanisms of plants for strontium uptake and retention is therefore essential for decision making concerning agriculture: are uptake rates low enough so that plants can serve as food? Or is radiostrontium accumulated so that plants should not be eaten but could be probably used for extracting strontium from water and soil in hot spots of pollution? The review presents a summary of studies about the origin of stable and radioactive strontium in the environment and effects coming from both internal and external exposure of plants. Mobility and availability of strontium to plant roots in soil are controlled by external factors such as chemical composition of the soil and pH, temperature and agricultural soil cultivation as well as soil biological networks built by microbial communities. Plant surfaces may receive input of strontium from deposition induced by atmospheric pollution or by acquisition from water through the whole immersed surface. Cells have entry mechanisms for strontium such as plasma membrane transporters for calcium and potassium. Part of absorbed strontium can be lost via processes discussed in this review. We give examples on strontium transfer factors for 149 plants to estimate plant absorption capacity for strontium from soil, water and air. Uptake efficiency of terrestrial and aquatic plants is deciding about their remediation potential to either remove radiostrontium by accumulation and rhizofiltration or to retain it in roots or aerial parts. Data of strontium content in soils after fallout and edible plants from long-term monitoring support the evaluation of the potential hazards posed by strontium input to the food chain.


Assuntos
Monitoramento Ambiental , Plantas/metabolismo , Isótopos de Estrôncio/análise , Estrôncio/análise , Biodegradação Ambiental , Cadeia Alimentar , Plantas/efeitos dos fármacos , Estrôncio/metabolismo , Isótopos de Estrôncio/metabolismo
7.
Sci Rep ; 7(1): 8615, 2017 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-28819227

RESUMO

We present the Sr isotopic composition of enamel of the most ancient deciduous tooth ever discovered in Italy to assess human mobility in Middle Pleistocene. Reconstructing ancient mobility is crucial for understanding human strategy at exploiting temporally and spatially patchy resources, with most studies focusing on indirect evidences, ultimately affecting our interpretation on hominin territoriality and energetic costs invested by hominin groups. Here, we use the high spatial resolution and micro-destructivity options offered by the Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry technique, to determine the 87Sr/ 86Sr intra-tooth variability of a human deciduous incisor from the Middle Pleistocene layers of the Isernia La Pineta site (Italy). We compared these data with the Sr isotopic signature of local micro-mammals, the broadest home-range of the macro-mammals and with modern plant samples. Our study reveals that while macro-mammals have possibly migrated through the landscape for up to 50 km, the pregnant woman from Isernia was probably local, given that the isotopic ratio of the enamel falls within the local range and is comparable with the signature of the local plants in a radius of 10 km. This is the first case study of Sr isotopic composition determination in such ancient deciduous tooth.


Assuntos
Esmalte Dentário/metabolismo , Migração Humana , Isótopos de Estrôncio/metabolismo , Dente Decíduo/metabolismo , Animais , Arqueologia/métodos , Feminino , Geografia , Hominidae , Humanos , Itália , Espectrometria de Massas/métodos
8.
Biol Rev Camb Philos Soc ; 92(1): 43-59, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26392144

RESUMO

Strontium (Sr) isotope analysis can provide detailed biogeographical and ecological information about modern and ancient organisms. Because Sr isotope ratios (87 Sr/86 Sr) in biologically relevant materials such as water, soil, vegetation, and animal tissues predominantly reflect local geology, they can be used to distinguish geologically distinct regions as well as identify highly mobile individuals or populations. While the application of Sr isotope analysis to biological research has been steadily increasing, high analytical costs have prohibited more widespread use. Additionally, accessibility of this geochemical tool has been hampered due to limited understanding of (i) the degree to which biologically relevant materials differ in their spatial averaging of 87 Sr/86 Sr ratios, and (ii) how these differences may be affected by lithologic complexity. A recently developed continental-scale model that accounts for variability in bedrock weathering rates and predicts Sr isotope ratios of surface water could help resolve these questions. In addition, if this 'local water' model can accurately predict 87 Sr/86 Sr ratios for other biologically relevant materials, there would be reduced need for researchers to assess regional Sr isotope patterns empirically. Here, we compile 87 Sr/86 Sr data for surface water, soil, vegetation, and mammalian and fish skeletal tissues from the literature and compare the accuracy with which the local water model predicts Sr isotope data among these five materials across the contiguous USA. We find that measured Sr isotope ratios for all five materials are generally close to those predicted by the local water model, although not with uniform accuracy. Mammal skeletal tissues are most accurately predicted, particularly in regions with low variability in 87 Sr/86 Sr predicted by the local water model. Increasing regional geologic heterogeneity increases both the offset and variance between modelled and empirical Sr isotope ratios, but its effects are broadly similar across materials. The local water model thus provides a readily available source of background data for predicting 87 Sr/86 Sr for biologically relevant materials in places where empirical data are lacking. The availability of increasingly high-quality modelled Sr data will dramatically expand the accessibility of this geochemical tool to ecological applications.


Assuntos
Ecologia/métodos , Ecologia/tendências , Paleontologia/métodos , Paleontologia/tendências , Isótopos de Estrôncio/análise , Animais , Mamíferos , Pesquisa/tendências , Solo , Isótopos de Estrôncio/metabolismo
9.
Appl Biochem Biotechnol ; 174(7): 2482-91, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25190302

RESUMO

Contamination by radioactive strontium ((90)Sr) is a significant environmental problem. Ureolytically driven calcium carbonate precipitation has been proposed for use in geotechnical engineering for soil remediation applications. In this study, 68 ureolytic bacterial strains were newly isolated from various environments. Of these, 19 strains were selected based on ureolytic activity shown when cultured on urea agar plates and identified through 16S rRNA gene sequencing. From these selected strains, Sporosarcina pasteurii WJ-2 (WJ-2) was selected for subsequent study. A simple method was developed to determine the effectiveness of microbially induced calcite precipitation (MICP). Unlike any other methods, it does not require advanced skills and sophisticated tools. Using this method, we were able to determine the ability of the bioconsolidated sand to retard the flow of crystal violet through the 25-mL column. Also, MICP by WJ-2 was evaluated for its potential to counteract Sr contamination in column experiments using natural sand. WJ-2-induced precipitation led to successful sequestration of approximately 80 % of the Sr from the soluble fraction of the sand. The utility of MICP in bioremediation was further confirmed through X-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectrometry.


Assuntos
Carbonato de Cálcio/metabolismo , Poluentes Radioativos do Solo/metabolismo , Sporosarcina/crescimento & desenvolvimento , Estrôncio/metabolismo , Biodegradação Ambiental , Isótopos de Estrôncio/metabolismo
10.
J Struct Biol ; 185(1): 79-88, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24511631

RESUMO

Using in situ (12 h) pulse-labeling of scleractinian coral aragonitic skeleton with stable 86Sr isotope, the diel pattern of skeletal extension was investigated in the massive Porites lobata species, grown at 5 m depth in the Gulf of Eilat. Several microstructural aspects of coral biomineralization were elucidated, among which the most significant is simultaneous extension of the two basic microstructural components Rapid Accretion Deposits (RAD; also called Centers of Calcification) and Thickening Deposits (TD; also called fibers), both at night and during daytime. Increased thickness of the 86Sr-labeled growth-front in the RADs compared to the adjacent TDs revealed that in this species RADs extend on average twice as fast as TDs. At the level of the individual corallite, skeletal extension is spatially highly heterogeneous, with sporadic slowing or cessation depending on growth directions and skeletal structure morphology. Daytime photosynthesis by symbiotic dinoflagellates is widely acknowledged to substantially increase calcification rates at the colony and the corallite level in reef-building corals. However, in our study, the average night-time extension rate (visualized in three successive 12 h pulses) was similar to the average daytime extension (visualized in the initial 12 h pulse), in all growth directions and skeletal structures. This research provides a platform for further investigations into the temporal calibration of coral skeletal extension via cyclic growth increment deposition, which is a hallmark of coral biomineralization.


Assuntos
Antozoários/crescimento & desenvolvimento , Antozoários/fisiologia , Calcificação Fisiológica/fisiologia , Isótopos de Estrôncio/metabolismo , Animais , Antozoários/metabolismo , Fotossíntese/fisiologia , Esqueleto
11.
Am J Phys Anthropol ; 151(3): 462-76, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23737109

RESUMO

Early Medieval England is described historically as a time when people migrated from the Continent to English shores. This study tests the hypothesis that those buried in the Bowl Hole cemetery, Bamburgh, Northumberland were nonlocally born, because of its royal status. Ninety-one male and female adult, and nonadult, skeletons were studied. Isotope ratios of strontium ((87) Sr/(86) Sr) and oxygen (δ(18) O) were generated for 78 individuals (28 females, 27 males, five "adults," 18 nonadults). The mean Sr value for human enamel was 0.71044, standard deviation (sd) 0.001, and the mean O (δw) value is -5.9‰, sd 1.6‰. Additionally, animal tooth enamel (mean Sr value 0.710587, sd 0.001; mean O value -6.5‰, sd 1.5‰), local soil (mean Sr value 0.709184, sd 0.0006), snail shells (mean Sr value 0.708888, sd 0.0001), and soil samples from a 5 km transect heading inland (mean Sr value 0.709121, sd 0.0003), were analyzed for an indication of the isotopic composition of bioavailable Sr in the modern environment and to assess the impact of sea-spray; water samples from a well, local rivers, and standing water were analyzed for local δ(18) O values (mean O value -6.4‰, relative to VSMOW, sd 2.8‰). Over 50% of those buried at Bamburgh were nonlocal. All ages and both sexes produced "nonlocal" signatures; some suggested childhood origins in Scandinavia, the southern Mediterranean or North Africa. Stature and other indicators of health status indicated differences in quality of life between local and migrant groups. These differences did not extend to burial practices.


Assuntos
Exoesqueleto/química , Osso e Ossos/química , Esmalte Dentário/química , Caramujos/química , Solo/química , Migrantes , Adolescente , Adulto , Animais , Cemitérios , Criança , Pré-Escolar , Inglaterra , Feminino , Nível de Saúde , História Medieval , Humanos , Lactente , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Isótopos de Oxigênio/metabolismo , Isótopos de Estrôncio/metabolismo
12.
J Agric Food Chem ; 61(28): 6822-31, 2013 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-23796314

RESUMO

The radiogenic isotopic compositions of inorganic heavy elements such as Sr, Nd, and Pb of the food chain may constitute a reliable geographic fingerprint, their isotopic ratios being inherited by the geological substratum of the territory of production. The Sr isotope composition of geomaterials (i.e., rocks and soils) is largely variable, and it depends upon the age of the rocks and their nature (e.g., genesis, composition). In this study we developed a high-precision analytical procedure for determining Sr isotopes in wines at comparable uncertainty levels of geological data. With the aim of verifying the possibility of using Sr isotope in wine as a reliable tracer for geographic provenance, we performed Sr isotope analyses of 45 bottled wines from four different geographical localities of the Italian peninsula. Their Sr isotope composition has been compared with that of rocks from the substrata (i.e., rocks) of their vineyards. In addition wines from the same winemaker but different vintage years have been analyzed to verify the constancy with time of the (87)Sr/(86)Sr. Sr isotope compositions have been determined by solid source thermal ionization mass spectrometry following purification of Sr in a clean laboratory. (87)Sr/(86)Sr of the analyzed wines is correlated with the isotopic values of the geological substratum of the vineyards, showing little or no variation within the same vineyard and among different vintages. Large (87)Sr/(86)Sr variation is observed among wines from the different geographical areas, reinforcing the link with the geological substratum of the production territory. This makes Sr isotopes a robust geochemical tool for tracing the geographic authenticity and provenance of wine.


Assuntos
Solo/química , Isótopos de Estrôncio/análise , Vinho/análise , Vinho/classificação , Temperatura Alta , Itália , Espectrometria de Massas/métodos , Isótopos de Estrôncio/metabolismo , Vitis/crescimento & desenvolvimento , Vitis/metabolismo
13.
Health Phys ; 101(2): 128-35, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21709498

RESUMO

A molecularly imprinted polymer (MIP) comprising dicyclohexano-18-crown-6 (DCH18C6) was synthesized as a Sr-selective sorbent for urine bioassay purposes. MIP particles (326 ± 2 nm diameter) were formed using acetone and acetonitrile (1:3 v/v) as the porogen, methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The DCH18C6-MIP particles were impregnated with additional DCH18C6 and treated further with NaOH to attain better binding affinity for Sr(2+). The effects of pH, ionic strength and amount of particles were evaluated for optimal extraction of (90)Sr(2+) from urine samples, as measured by liquid scintillation analysis (LSA). After up to 94% of (90)Y was removed by precipitation with TiO(2), DCH18C6-MIP particles were applied for selective SPE of (90)Sr remaining in the urine matrix for final LSA.


Assuntos
Éteres de Coroa/química , Impressão Molecular/métodos , Monitoramento de Radiação/métodos , Isótopos de Estrôncio/urina , Reagentes de Ligações Cruzadas/química , Éteres de Coroa/síntese química , Humanos , Concentração de Íons de Hidrogênio , Metacrilatos/química , Concentração Osmolar , Contagem de Cintilação/métodos , Sensibilidade e Especificidade , Isótopos de Estrôncio/metabolismo
14.
Ann Hum Biol ; 37(3): 325-46, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20367186

RESUMO

Strontium isotopes are a powerful tool which provide information about provenance directly from the tissues of humans rather than the grave context and burial goods. Geographical variation in strontium isotopes is primarily controlled by the underlying geology but there are many other factors that need to be considered before migratory individuals can be identified. Consequently, despite many studies which have shown that the method works well, it is clear that much remains to be clarified and it will not work for every question or in every place. It rests on the assumption that people were sourcing their food locally and that there is a measurable strontium isotope difference between the place the person migrated from and the place they migrated to. As migrants may deliberately seek out familiar soil types and terrains in their new homeland, some questions surrounding major migration events may prove intractable for this technique. Other factors that can create heterogeneity or homogeneity leading to false positives or false negatives, such as human choices or coastal subsistence, are explored and the metabolism of strontium into human tooth enamel is discussed. Several models of land-use choices by humans are presented to highlight the subtleties inherent in the isotope data and these are used to interpret archaeological human isotope ratios from three studies.


Assuntos
Evolução Biológica , Esmalte Dentário/metabolismo , Emigração e Imigração , Datação Radiométrica/métodos , Isótopos de Estrôncio/metabolismo , África , Densidade Óssea , Osso e Ossos/metabolismo , Esmalte Dentário/química , Ecossistema , Humanos , Índia , Isótopos de Estrôncio/análise
15.
Oecologia ; 153(4): 943-50, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17593400

RESUMO

The use of the landscape by animals is predicted to be a function of their body size. However, empirical data relating these two variables from an array of body sizes within a single mammalian community are scarce. We tested this prediction by assessing landscape use of mammals by analyzing strontium (Sr) isotope signatures found in mammalian hard tissues representing a 3,000-year record. We examined: (1) the Sr-determined landscape area of small (approximately 100 g), medium (approximately 1,500 g) and large (approximately 100,000 g) mammals, and; (2) whether the area used by these mammals varied during periods of environmental change. Strontium isotope values were obtained from 46 specimens from the Holocene paleontological deposits of Lamar Cave and Waterfall Locality in Wyoming, USA, as well as from 13 modern ungulate specimens from the same area. Our data indicate that medium- and large-sized species use larger percentages of the landscape than do species of small body size. The isotope values for specimens from each of the paleontological sites are similar across all stratigraphic levels, suggesting no change in home range over the last 3,000 years, even though climate is known to have fluctuated at these sites over this time period. Further, our study verifies that the fossil localities represent the local community. Where bedrock geology is appropriate, the use of strontium isotope analyses provides a valuable tool for discerning landscape use by vertebrate communities, an important though generally difficult aspect of an ancient species niche to identify.


Assuntos
Ecossistema , Mamíferos/fisiologia , Isótopos de Estrôncio/análise , Animais , Tamanho Corporal , Osso e Ossos/metabolismo , Esmalte Dentário/metabolismo , Dentina/metabolismo , Comportamento Alimentar , Fósseis , Mamíferos/anatomia & histologia , Isótopos de Estrôncio/metabolismo , Wyoming
16.
Int Surg ; 60(4): 206-8, 1975 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1123271

RESUMO

Microspheres 25 plus or minus 5 microns in diameter labeled with Ce141 and Sr85 were used to study the influence of oligemic shock on any arteriovenous anastomoses of the small intestine mucosa of dogs and rabbits. We found no open AVA's larger than 20 microns in diameter either before or during oligemic shock.


Assuntos
Anastomose Arteriovenosa/fisiopatologia , Choque/fisiopatologia , Animais , Determinação da Pressão Arterial , Isótopos de Cério/metabolismo , Cães , Intestino Delgado/irrigação sanguínea , Fígado/metabolismo , Circulação Hepática , Microcirculação , Microesferas , Coelhos , Choque Hemorrágico/fisiopatologia , Isótopos de Estrôncio/metabolismo
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