Substantial heterogeneity of carbon and oxygen stable-isotope compositions of single layers or specimens of natural carbonate materials: New evidence from replicate sampling of continental carbonates affirms previous evidence from marine limestones

2021 ◽  
Vol 91 (5) ◽  
pp. 464-478
Author(s):  
Laura A. Dupont ◽  
L. Bruce Railsback ◽  
Julia E. Cox
Keyword(s):  
Stable Isotope ◽  
Single Sample ◽  
Published Data ◽  
Analytical Uncertainty ◽  
Uncertainty Of Measurements ◽  
Significant Difference ◽  
Oxygen Stable Isotope ◽  
Continental Carbonates ◽  
Carbonate Materials ◽  
Replicate Sampling

ABSTRACT The uncertainty of measurements of carbon and oxygen stable-isotope ratios of carbonate materials is commonly assumed to be the analytical uncertainty determined from replicate analyses of single samples, but this ignores the possibility that heterogeneity of the material studied is greater than the analytical uncertainty. To test this question, we took eight samples from each of 13 layers or specimens of various non-marine (“continental”) carbonates and found ranges of δ13C and δ18O of 0.3 to 5.1‰, all exceeding the range of the typical lab-reported analytical uncertainty, ± 0.1‰, placed around single samples. These results are similar to previous replicate sampling of marine limestone layers, which revealed ranges of 0.2 to 2.8‰. Both sets of results, and other published data, demonstrate that analytical uncertainty derived from replicate analysis of a single sample is not a valid estimate of the uncertainty of δ13C or δ18O values characterizing a layer or specimen, and they remind us that we should not place great credence in anomalies or events defined by single samples of layers or specimens, regardless of the replication of analysis of that single sample. Our results indicate that the required layer-level or specimen-level uncertainty can be derived only from replicate sampling at different locations in layers or specimens, and that the layer-level or specimen-level uncertainty is inevitably greater than typical lab-reported analytical uncertainty. Credibility of anomalies or events in time series would be increased by replicate sampling of a random or dispersed subset of layers to estimate the variability of all layers and/or by replicate sampling of layers at and around a potential but unconfirmed event. The significance of the variability discussed above is evident in use of δ18O data to estimate paleotemperatures, where a difference of 1‰ in δ18O implies a difference of 4°C in temperature. Use of a single sample resulting in mischaracterization of the δ18O of an ancient material by 1.5‰ relative to the true mean for that material (which our results suggest is quite possible) would lead to a corresponding misestimation of temperature of 6°C, a significant difference in paleoenvironmental studies.

scholarly journals Lutetian conid snails from the Paris and Hampshire Basins as seasonality archives of the middle Eocene

2020 ◽  
Author(s):  
Alexander Clark ◽  
Johan Vellekoop ◽  
Zita Keleman ◽  
Robert Speijer
Keyword(s):  
Stable Isotope ◽  
Sea Water ◽  
Middle Eocene ◽  
Internal Variability ◽  
Marine Biodiversity ◽  
Published Data ◽  
Paris Basin ◽  
Isotope Data ◽  
Carbon And Oxygen Isotope ◽  
Oxygen Stable Isotope

<p>During the Lutetian (middle Eocene, 48-41 Ma), Earth’s climate was in transition from greenhouse to icehouse conditions, sometimes referred to as a “doubthouse climate”. These circumstances allowed the Paris Basin (France) and Hampshire Basin (UK) to be hotspots for marine biodiversity, hosting a diverse assemblage of molluscs, including members of the Conidae family. Most species within the family are known to live for multiple years, possibly up to a decade, in fully marine conditions and mostly in shallow waters. Under these fully marine conditions, Conidae shells would be excellent recorders of sea water temperatures, allowing paleotemperature reconstruction for the two basins. However, climatic parameters such as temperature extremes or seasonality have not been well documented in the two basins during the Lutetian, with only a handful of studies available [Andreasson & Schmitz 2000, Huyghe et al. 2015]. Here, we made longitudinal and latitudinal comparisons between the two basins, using carbon and oxygen stable isotope data measured on different Conidae species, in order to provide seasonality reconstructions in north-western Europe. The focus of this research is mainly on assessing isotopic variation of seasonality within a basin and comparison between basins, including previously published data. SEM and cold cathodoluminescence shows that for both basins the preservation of the mollusc carbonate is sufficient to allow for approximations of the original environmental conditions. Three specimens from each basin were sampled by means of manual drilling along the growth axis of the shells. Obtained stable carbon and oxygen isotope data were used to reconstruct variation in paleotemperature and productivity. Following the methodology of Kobashi & Grossman 2003, patterns in the isotopic signature throughout the life of each specimen give an indication of the environmental reconstruction and any internal variability. By comparing existing and newly collected data from the same localities and family, we examine whether differences in seasonality are species-specific, due to climatic variation, or reflect environmental differences. <br>Andreasson, F.P., Schmitz, B. (2000) Temperature seasonality in the early middle Eocene North Atlantic region: Evidence from stable isotope profiles of marine gastropod shells, GSA Bulletin, 112, 628-640. <br>Huyghe, D., Lartaud., F., Emmanuel, L., Merle, D., Renard, M. (2015) Palaeogene climate evolution in the Paris Basin from oxygen stable isotope (δ18O) compositions of marine molluscs. Journal of the Geological Society, 172, 576-587. <br>Kobashi, T., Grossman, E.L. (2003) The oxygen isotopic record of seasonality in Conus shells and its application to understanding late middle Eocene (38 Ma) climate, Paleontological Research, 7, 343-355. </p>

scholarly journals OXYGEN STABLE ISOTOPE VARIATION IN LATE HOLOCENE ICE WEDGES IN YAMAL PENINSULA AND SVALBARD

2015 ◽  
Vol 8 (3) ◽  
pp. 36-54 ◽  
Author(s):  
Yurij K. Vasil'chuk ◽  
Nadine A. Budantseva ◽  
Hanne H. Christiansen ◽  
Julia N. Chizhova ◽  
Alla C. Vasil'chuk ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Late Holocene ◽  
Yamal Peninsula ◽  
Oxygen Stable Isotope ◽  
Isotope Variation

scholarly journals Nutritional and micronutrient status of adolescent schoolgirls in eastern Sudan: A cross-sectional study

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1831
Author(s):  
Hyder M. Mahgoub ◽  
Omar E. Fadlelseed ◽  
Ammar H. Khamis ◽  
Jalal A. Bilal ◽  
Ishag Adam
Keyword(s):  
Cross Sectional Study ◽  
High Rate ◽  
Nutrition Status ◽  
Published Data ◽  
Sectional Study ◽  
Cross Sectional ◽  
Micronutrient Status ◽  
Significant Difference ◽  
More Care ◽  
Eastern Sudan

Background: Adolescents, especially girls, are susceptible to malnutrition and their diet must be adequate to support their very rapid growth and development. Currently, there is little published data on the nutritional state amongst adolescent girls in Sudan. Methods: A cross sectional study was conducted to assess the nutritional and micronutrient status of adolescent schoolgirls in eastern Sudan during the period of January-February 2015. Weight and height were measured using standard methods. Haemoglobin and ferritin levels were measured using blood samples, and blood films for malaria and stool samples for Schistosoma mansoni were investigated. Nutritional status was assessed according to the WHO 2006 reference values. Copper and zinc concentrations were measured by atomic absorption. Results: Twenty-five (13.7%) out of 183 girls were stunted. Seventy (38.3%) were thin; 17.5, 9.3 and 11.5% had mild, moderate and severe thinness, respectively. Only 10 (5.5%) and six (3.3%) girls were overweight and obese, respectively. The prevalence of anaemia was 77.0%. While there was no significant difference in the haemoglobin, ferritin, copper levels and thinness; thin children had significantly lower zinc (P=0.007). Conclusions: There is a high rate of stunting, thinness and anaemia among adolescent schoolgirls in eastern Sudan. More care has to be taken in order to provide a better nutrition status in the area.

Lack of Oncological Benefit from Bursectomy in Radical Gastrectomy: A Systematic Review

2021 ◽  
pp. 1-10
Author(s):  
Pankaj Kumar Garg ◽  
Ashish Jakhetiya ◽  
Kiran Kalyan Turaga ◽  
Rahul Kumar ◽  
Andreas Brandl ◽  
...  
Keyword(s):  
Overall Survival ◽  
Gastric Adenocarcinoma ◽  
Systematic Reviews ◽  
Disease Recurrence ◽  
Assessment Tools ◽  
Published Data ◽  
Radical Gastrectomy ◽  
Significant Difference ◽  
Omental Bursa ◽  
Meta Analyses

<b><i>Background:</i></b> Resection of the omental bursa has been suggested to reduce peritoneal recurrence and facilitate a complete oncological resection during a gastrectomy. The addition of this procedure increases technical complexity and prolongs the procedure. Published data regarding the oncological benefit of this procedure are conflicting. We hypothesized that a bursectomy during a radical gastrectomy does not improve overall survival. <b><i>Methods:</i></b> In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline, a comprehensive literature search of 3 electronic databases (PubMed, Scopus, and Embase) was conducted to identify the clinical studies that compared bursectomy with no-bursectomy in radical gastrectomy for gastric adenocarcinoma. Qualitative and quantitative data synthesis was performed using RevMan software. A random-/fixed-effect modeling was used depending upon the heterogeneity. Bias and quality assessment tools were applied. The study was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42019116556). <b><i>Results:</i></b> Of 8 studies assessing the role of bursectomy in gastric adenocarcinoma, 6 (75%) were included – of which 2 (33%) are randomized controlled trials. Of 2,904 patients, 1,273 (%) underwent a bursectomy. There was no statistically significant difference in either overall survival (hazard ratio [HR] = 0.89, 95% CI 0.75–1.06, <i>I</i><sup>2</sup> = 14%) or disease recurrence (HR = 1.01, 95% CI 0.84–1.20, <i>I</i><sup>2</sup> = 22%) in the bursectomy group compared to the no-bursectomy group. <b><i>Conclusion:</i></b> There is no additional oncological benefit of adding bursectomy to radical gastrectomy in all patients with gastric adenocarcinoma.

Incidental uptake of 18F-fluorodeoxyglucose in the prostate gland

2014 ◽  
Vol 53 (06) ◽  
pp. 249-258 ◽  
Author(s):  
R. Sadeghi ◽  
L. Giovanella ◽  
G. Treglia ◽  
F. Bertagna
Keyword(s):  
Fdg Pet ◽  
Prostate Gland ◽  
Significant Risk ◽  
Published Data ◽  
Pooled Prevalence ◽  
Pet Ct ◽  
Significant Difference ◽  
Risk Of Malignancy ◽  
18F Fdg ◽  
Fdg Pet Ct

SummaryAim: To perform a systematic review and meta-analysis of published data on the prevalence and risk of malignancy of pros- tatic incidental uptake (PIU) detected by flu- orine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) or PET/computed tomography (PET/CT). Patients, material, methods: A comprehensive literature search of studies published up to February 2014 was performed. Pooled prevalence and malignancy risk of PIU were calculated on a per patient-based analysis including 95% confidence interval (95%CI). Furthermore, we assessed some parameters as potential predictors of malignant PIU. Results: Six studies including 47925 patients who underwent 18F-FDG PET/CT were selected. Pooled prevalence of PIU was 1.8% (95%CI: 1.3–2.3%). Overall, 444 patients with PIU were further evaluated and 121 underwent biopsy. The pooled risk of malignancy in patients with PIU further evaluated or verified by biopsy were 17% (95%CI: 12–23%) and 62% (95%CI: 54–71%), respectively. A higher mean age was observed in the group of malignant PIUs compared to benign PIUs. There was a trend towards a higher mean SUVmax in the group of malignant PIUs but without a statistically significant difference compared to benign PIUs. Peripheric site of PIU but not presence or absence of calcification was a predictor of malignancy. Conclusions: PIU is observed in about 1.8% of 18F-FDG PET/CT scans performed in male patients carrying a significant risk of malignancy. Therefore, whenever a PIU is detected further investigation is warranted to exclude malignancy, in particular when PIU is located in the peripheric site of prostate gland.

Effect of Muscle Activation on the Gravity Stress View in Unstable Weber B Ankle Fractures

2020 ◽  
Vol 41 (11) ◽  
pp. 1342-1346
Author(s):  
Kimberly K. Broughton ◽  
Caroline Williams ◽  
Christopher P. Miller ◽  
Kristen Stupay ◽  
John Y. Kwon
Keyword(s):  
Muscle Activation ◽  
False Negative ◽  
Ankle Fractures ◽  
Published Data ◽  
Neutral Position ◽  
Distal Fibula ◽  
Level Of Evidence ◽  
Negative Results ◽  
False Negative Results ◽  
Significant Difference

Background: In the setting of apparently isolated distal fibula fractures, the gravity stress view (GSV) is a validated method to determine mortise stability. There is currently no published data evaluating whether dynamic muscle activation can reduce an unstable mortise. If patients with instability can overcome gravity, resultant images could yield false-negative results. The goal of this investigation was to determine if patient effort can influence medial clear space (MCS) measurements in proven unstable bimalleolar-equivalent ankle fractures. Methods: Patients presenting with Weber B fibula fractures were assessed for mortise stability using the GSV. If the GSV demonstrated instability based on MCS widening >4 mm, 3 additional views were performed: GSV with an assistant maintaining the ankle in a neutral position; GSV with the patient actively dorsiflexing to neutral; and GSV with the patient actively dorsiflexing and supinating the foot. Twenty-four consecutive patients met inclusion criteria, with a mean age of 48.7 (range, 22-85) years. Fifteen patients (62.5%) were female and 9 (37.5%) were male. The laterality was evenly divided. Results: The mean MCS was 5.8 ± 2.0 6.0 ± 2.6, and 6.2 ± 2.7 mm for the manual assist, active dorsiflexion, and active supination radiograph measurement groups, respectively ( P = .434). Only 5 of 24 subjects had any measurable decrease in their MCS with active supination, with a maximum change of 1.2 mm. The remainder of the patients had an increase in MCS ranging from 0.1 to 4.0 mm. Conclusion: There was no significant difference between measurement states indicating that muscle activation is unlikely to yield a false-negative result on GSV. Mortise instability, secondary to deep deltoid injury in the presence of gravity stress, is unlikely to be actively overcome by dynamic stabilizers, supporting the validity and specificity of the GSV. Level of Evidence: Level III, prospective study.

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