Determination of oxygen-18 in water contained in biological samples by charged particle activation

Wood, Richard; Nagy, Kenneth A.; MacDonald, Norman S.; Wakakuwa, S.T.; Beckman, Richard J.; Kaaz, H.

doi:10.1021/ac60354a038

Cited by 193 publications

(59 citation statements)

References 19 publications

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“…Specific activity of tritium in the water was measured by liquid scintillation spectrometry (Nagy 1983). Level of 18 O specific activity was measured by an autogamma counting system (Packard) after converting 18 O to gamma-emitting 18 F by cyclotron-generated proton activation (Wood et al 1975). Blood samples from three noninjected nestlings from different nests were treated similarly to measure background levels of 18 O and tritium.…”

Section: Short Communicationsmentioning

confidence: 99%

Effect of Investigator Disturbance on Nest Attendance and Egg Predation in Eurasian Oystercatchers

Verboven¹,

Ens²,

Dechesne³

2001

Auk

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ABSTRACT.-Measures of repeatability have long been used to assess patterns of variation in egg size within and among females. We compared different analytical approaches for estimating repeatability of egg size of Black Brant. Separate estimates of repeatability for eggs of each clutch size and laying sequence number varied from 0.49 to 0.64. We suggest that using the averaging egg size within clutches results in underestimation of variation within females and thereby overestimates repeatability. We recommend a nested design that partitions egg-size variation within clutches, among clutches within females, and among females. We demonstrate little variation in estimates of repeatability resulting from a nested model controlling for egg laying sequence and a nested model in which we assumed laying sequence was unknown.Egg size represents the unit of investment in a reproductive attempt for birds. Accordingly, researchers have long been interested in variation in egg size and its adaptive significance. Repeatability is a measure of the proportion of variation in a trait that is due to differences among individuals. Therefore, estimates of repeatability of egg size split the total phenotypic variation in egg size into within-individual and among-individual components. Falconer (1989) describes that partitioning of the phenotypic variance in terms of the origin of the different variance components. Variation in egg size among individuals is caused by a combination of genetic and environmental differences. Variation in egg size within an individual among years is caused by temporary environmental differences between reproductive attempts. Falconer (1989) goes on to demonstrate that estimates of repeatability are useful in the context of quantitative genetics because they set upper limits to levels of heritable variation.Falconer (1989) states that estimates of repeatability can be based on measures of a characteristic that are 4 E-mail: paulflint@usgs.gov repeated in either time or space. Following Falconer's (1989) descriptions, egg size is repeated in both time and space-where time refers to different nesting attempts and space refers to eggs within a specific nesting attempt (i.e. clutch). In many cases researchers estimating repeatability of egg size use the average egg size within clutches (e.g. Lessells et al. 1989, Flint and Sedinger 1992, Flint and Grand 1996. However, that approach ignores some of the phenotypic variation in egg size within individuals (e.g. within clutches) and may have been used because researchers were uncertain how to deal with multiple measurements within clutches statistically. Other researchers have used a nested design to partition variance among females, within females among years, and within females within years (i.e. clutches) (LeBlanc 1987, Erikstad et al. 1998, Flint and Grand 1999.In this paper, we compare those two approaches in terms of estimates of repeatability. We decompose each estimate into its variance components and discuss each estimate in the context of quanti...

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Section: Short Communicationsmentioning

confidence: 99%

Effect of Investigator Disturbance on Nest Attendance and Egg Predation in Eurasian Oystercatchers

Verboven¹,

Ens²,

Dechesne³

2001

Auk

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“…Blood samples were refrigerated and later microdistilled to obtain pure water (Wood et al 1975). The specific activity of tritium was determined in duplicate samples by liquid scintillation spectrometry (Kontron scintillation counter, Basel, Switzerland).…”

Section: Measurementsmentioning

confidence: 99%

“…Samples were counted for 10 min and counts were corrected for quenching using a series of quenched standards. Levels of l8 O specific activity were measured in triplicate by an autogamma counting system (Packard, Downers Grove, IL) after converting 18 0 to gamma-emitting 18 F by cyclotrongenerated proton activation (Wood et al 1975). Blood samples from three non-injected rodents of each species were treated similarly to measure background levels of 18 0 and tritium.…”

Section: Measurementsmentioning

confidence: 99%

Body size, granivory and seasonal dietary shifts in desert gerbilline rodents

et al. 1997

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1. Desert gerbilline rodents consume mainly plant material, in particular seeds. However, seeds are less available following winter rains than in summer and many rodents shift their diets from predominantly seeds to ones containing more vegetation. This shift results in a proportionately greater preformed water intake and, as these rodents do not drink, an increase in the water influx to field metabolic rate ratio (WI : FMR; ml kJ–1). Thus, this ratio is indicative of the food consumed, being low when gerbils are consuming seeds and high when consuming green vegetation. 2. Smaller animals are more dependent on a highly digestible, high energy diet such as seeds and are more vulnerable to extreme air temperatures than are larger animals. It was predicted that: (1) gerbils consume less seeds in winter than in summer but the difference between seasons in seed intake is less pronounced in smaller than in larger rodents; and (2) smaller gerbils are more sensitive to extreme air temperatures than are larger gerbils. To examine these hypotheses, two coexisting desert gerbils, Gerbillus henleyi (8–12 g) and Meriones crassus (50–110 g), were studied. 3. It was predicted that: (1) the WI : FMR ratio would be greater in winter than in summer in both species, but the proportionate increase would be smaller in G. henleyi than in M. crassus; and (2) energy expenditure would be greater in winter than in summer in both species, but the proportionate increase would be greater in G. henleyi than in M. crassus. To test these predictions, winter and summer water influx and field metabolic rates in these species were measured under free‐living conditions using doubly labelled water. 4. The WI : FMR ratio in summer was 0·048 in G. henleyi and 0·069 in M. crassus, indicating that G. henleyi was consuming proportionately more seeds than M. crassus. In winter, the ratio was 0·052 in G. henleyi, indicating that there was little change in dietary composition and that this species was still consuming mainly seeds. In contrast, the ratio in M. crassus rose to 0·127, indicating a shift to a diet containing more green vegetation. The relatively higher seed intake by G. henleyi than M. crassus in both seasons and the small, if any, seasonal change in seed intake in G. henleyi agrees with the hypothesis of body size and seed intake in gerbils. Winter FMR increased over summer FMR in both species, as predicted; however, the expected greater increase in G. henleyi relative to M. crassus did not occur. The winter FMR was 1·52 times the summer FMR in G. henleyi and 1·53 times the summer FMR in M. crassuss.

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“…Tritium activity was measured in duplicate or triplicate on 10-AL samples of water in a Beckman LS7500 scintillation counter. 1'0 in the remaining water from each sample was analyzed in duplicate or triplicate at Nagy's (1983) laboratory at the University of California at Los Angeles by proton activation of 1O to '8F with subsequent counting of '8F in a gamma counter (Wood et al 1975, Nagy 1980). Standards were made by diluting 100-AL injection solution in 20.0 mL of distilled water and were analyzed in triplicate.…”

Section: Introductionmentioning

confidence: 99%

Reproductive Energetics and Prey Harvest of Leach's Storm‐Petrels in the Northwest Atlantic

Montevecchi¹,

Birt-Friesen²,

Cairns³

1992

Ecology

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Leach's Storm-Petrels (Oceanodroma leucorhoa), the smallest and most abundant seabirds that breed in the northwest Atlantic, are not usually included in avian energetics models. To round out an energy analysis of seabirds spanning the full range of body sizes in the northwest Atlantic, the field metabolic rates (FMRs) of breeding Leach's Storm-Petrels were measured using doubly labeled water techniques (DLW). Metabolic, dietary and, demographic data were used as inputs in a populations energetics model to estimate the energy requirements and prey harvests of the Leach's Storm-Petrel population of eastern North America. Ecological Society of AmericaFMRs An intra-specific, inter-colony difference in FMR is suggested: FMRs measured in a Newfoundland colony were significantly higher than those determined with the same DLW procedure in the Bay of Fundy near the southern limit of the species' breeding range in the northwest Atlantic. Differences in ambient temperatures and wind speed associated with different oceanographic regimes may generate energetic differences. Like inter-colony differences in feeding ecology, inter-colony differences in FMR need to be considered in population and community energetics models and in meso-and mega-scale extrapolations.

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Determination of oxygen-18 in water contained in biological samples by charged particle activation

Cited by 193 publications

References 19 publications

Effect of Investigator Disturbance on Nest Attendance and Egg Predation in Eurasian Oystercatchers

Effect of Investigator Disturbance on Nest Attendance and Egg Predation in Eurasian Oystercatchers

Body size, granivory and seasonal dietary shifts in desert gerbilline rodents

Reproductive Energetics and Prey Harvest of Leach's Storm‐Petrels in the Northwest Atlantic

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