U-series isochron dating: A generalized method employing total-sample dissolution

1991 ◽  
Vol 55 (2) ◽  
pp. 555-564 ◽  
Author(s):  
Shangde Luo ◽  
Teh-Lung Ku
Keyword(s):  
Total Sample ◽  
Sample Dissolution

Sequential analyses of actinides in large-size soil and sediment samples with total sample dissolution

2018 ◽  
Vol 187 ◽  
pp. 73-80 ◽  
Author(s):  
Maoyi Luo ◽  
Shan Xing ◽  
Yonggang Yang ◽  
Lijuan Song ◽  
Yan Ma ◽  
...  
Keyword(s):  
Total Sample ◽  
Sediment Samples ◽  
Large Size ◽  
Sample Dissolution ◽  
Sequential Analyses ◽  
Soil And Sediment

Geochronology and Palaeomagnetic Records of the Snaigupėlė Section in South Lithuania

2015 ◽  
Vol 42 (1) ◽  
Author(s):  
Valentinas Baltrūnas ◽  
Fedor E. Maksimov ◽  
Vladislav Yu. Kuznetsov ◽  
Bronislavas Karmaza ◽  
Valentas Katinas
Keyword(s):  
Analytical Data ◽  
Lacustrine Sediments ◽  
Total Sample ◽  
Magnetic Polarity ◽  
The South ◽  
Three Samples ◽  
Sample Dissolution ◽  
Eemian Interglacial

AbstractThe interglacial deposits in the South Lithuanian Snaigupėlė outcrop and borehole Snaigupėlė-705 are marked for different bedding conditions though the sections are in proximity of each other. In the borehole section, the interglacial deposits are thicker and bedding at a greater depth than the analogous deposits of the outcrop. In the Snaigupėlė outcrop, the highest compatibility of isochronic-correction dates, calculated using L/L (method of leaching) and TSD (method of total sample dissolution) models, was determined for combination of three samples. With the help of the f value (section of isochrones in the axis of ordinates), the contribution of the primary pollution with thorium was determined where, as based on corrected analytical data, isochronic-correction dating was performed: 127+18-14ka years for the L/L model and 132+22-16ka for the TSD model. Palaeomagnetic investigations showed that the section of lacustrine sediments in the lower part of Snaigupėlė outcrop were orientated by reversed magnetic excursion and in the upper part by normal magnetic polarity. Collation of the obtained data with the global geomagnetic scale showed that the palaeomagnetic in-version observed in the Snaigupėlė section was related with the Blake Event in the Eemian Interglacial.

First 230Th/U date of Middle Pleistocene peat bog in Siberia (key section Krivosheino, Western Siberia)

2012 ◽  
Vol 39 (4) ◽  
pp. 241-251 ◽  
Author(s):  
Fedor Maksimov ◽  
Stanislav Laukhin ◽  
Khikmatulla Arslanov ◽  
Vladislav Kuznetsov ◽  
Galina Shilova
Keyword(s):  
Western Siberia ◽  
Total Sample ◽  
Middle Pleistocene ◽  
Peat Bog ◽  
Peat Layer ◽  
Climate Conditions ◽  
Palynological Data ◽  
Sample Dissolution

Abstract A 14C date older than 53900 yrs BP was obtained for the uppermost part of the buried peat bog in Krivosheino section (Middle Pleistocene of Western Siberia). These sediments also yielded 230Th/U dates of 195−9.1+10.8 ka using the leachate alone (L/L) and 204−13+17 ka using total sample dissolution (TSD) models. Peculiarities of 230Th/U dating are discussed. Palynological investigation of the buried peat bog together with underlying and overlaying sediments, and comparison with palynological data from Baikal and Elgygytgyn lakes revealed that the peat layer in Krivosheino section was formed at the end of Shirta Interglacial (Marine Isotopic-Oxygenous stages MIS-7), when climate conditions at all studied sites were more severe compared to the modern ones.

scholarly journals Rapid Extraction Chemistry Using a Single Column for 230Th/U Dating of Quaternary Hydrothermal Sulfides

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 983
Author(s):  
Li-Sheng Wang ◽  
Ye-Jian Wang ◽  
Jun Ye ◽  
Xue-Feng Wang ◽  
Ju-Le Xiao ◽  
...  
Keyword(s):  
High Precision ◽  
Total Sample ◽  
Secular Equilibrium ◽  
Single Column ◽  
Sample Dissolution ◽  
The Matrix ◽  
Hydrothermal Sulfides ◽  
Simplified Procedure ◽  
Age Constraints ◽  
238U Activity

230Th/U dating can provide high-precision age constraints on Quaternary hydrothermal sulfides. However, low content of U and Th often involves extraction chemistry for the separation and enrichment of U and Th, but these chemical processes are very complex. We developed a simplified procedure consisting of total sample dissolution and single-column extraction chemistry, which can reduce the time and improve the accuracy of the dating. Concentrated HCl-HF followed by HNO3 was added to ensure complete dissolution. A single column filled with 0.4 mL of AG 1-X8 anion resin was used, then 8 M HNO3, 8 M HCl and 0.1 M HNO3 were used to elute most of the matrix metals, Th and U. This process provided more than 95% recoveries for U and Th, and negligible blanks. Meanwhile, Pb and Bi interferences were tested and showed no effect on the U and Th isotope ratio. The 230Th/238U activity of the Geological Survey of Japan geochemical reference material JZn-1 in secular equilibrium was determined and showed a radioactive equilibrium (1.00 ± 0.01, n = 5, all errors 2σ) and an in-house standard QS-1 was consistent to 0.0078 ± 0.0001 (n = 8, ±2σ) with an average age of 705 ± 10 yrs BP (n = 8, ±2σ). The technique greatly shortens the sample preparation time and allows more concise and effective analysis of U-Th isotopes. It is ideally suited for the high-precision 230Th/U dating of Quaternary submarine hydrothermal sulfides and sulfides from other settings.

Teacher Identification of Elementary School Children with Hearing Loss

1978 ◽  
Vol 9 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Richard H. Nodar
Keyword(s):  
Elementary School ◽  
Hearing Loss ◽  
School Children ◽  
Elementary School Children ◽  
Total Sample ◽  
Hearing Impaired ◽  
Teacher Interviews ◽  
Teacher Screening ◽  
Children With Hearing Loss ◽  
Hearing Problems

The teachers of 2231 elementary school children were asked to identify those with known or suspected hearing problems. Following screening, the data were compared. Teachers identified 5% of the children as hearing-impaired, while screening identified only 3%. There was agreement between the two procedures on 1%. Subsequent to the teacher interviews, rescreening and tympanometry were conducted. These procedures indicated that teacher screening and tympanometry were in agreement on 2% of the total sample or 50% of the hearing-loss group. It was concluded that teachers could supplement audiometry, particularly when otoscopy and typanometry are not available.

Cardiorespiratory fitness is positively associated with both healthy and western dietary pattern in Iranian middle-aged

2020 ◽  
pp. 1-10
Author(s):  
Hossein Shahinfar ◽  
Farhang Djafari ◽  
Nadia Babaei ◽  
Samira Davarzani ◽  
Mojdeh Ebaditabar ◽  
...  
Keyword(s):  
Cardiorespiratory Fitness ◽  
Dietary Patterns ◽  
Dietary Pattern ◽  
Principal Component ◽  
Total Sample ◽  
Linear Regression Models ◽  
Middle Aged ◽  
Anthropometric Measures ◽  
Western Dietary Pattern ◽  
Healthy Dietary Pattern

Abstract. Background: The association between dietary patterns and cardiorespiratory fitness (CRF) is not well established. Objective: We sought to investigate association between a posteriori dietary pattern and CRF in middle-aged adults. Design: Adults (n = 276), aged 20–74 years, who were residents of Tehran, Iran were recruited. Diet was assessed by using a validated 168-item semi-quantitative food frequency questionnaire. Principal component analysis was used to derive dietary patterns. Socio-economic status, anthropometric measures, body composition, and blood pressure were recorded. CRF was assessed by using a graded exercise treadmill test. Analysis of variance and linear regression models were used to discern the association between dietary patterns and CRF. Results: Higher scores of the healthy dietary pattern had no association with VO2max (p = 0.13 ). After controlling for potential confounders, VO2max was positively associated across tertiles of healthy dietary patterns (p < 0.001). Higher adherence to the “mixed” dietary pattern was inversely related to VO2max (p < 0.01). After adjusting for confounders, the significant association disappeared (p = 0.14). Higher scores of the “Western” dietary pattern was not associated with VO2max (p = 0.06). However, after controlling for potential confounders, VO2max was positively associated with the “Western” dietary pattern (p = 0.01). A positive linear association between the “healthy” dietary pattern and CRF for the total sample (R2 = 0.02; p < 0.01) were presented. Conclusions: Overall, our findings suggest that higher adherence to a “healthy” and “Western” dietary pattern was positively associated with CRF. However, further studies are required to examine and clarify the causal relationship between dietary patterns and CRF.

Seasonal Variation of Suicide in the City of São Paulo, Brazil, 1996–2010

Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Fernando Madalena Volpe
Keyword(s):  
Seasonal Pattern ◽  
Total Sample ◽  
Sao Paulo ◽  
Seasonal Patterns ◽  
São Paulo ◽  
Health Statistics ◽  
Males And Females ◽  
June July ◽  
The City ◽  
Over Time

Background: In light of the few reports from intertropical latitudes and their conflicting results, we aimed to replicate and update the investigation of seasonal patterns of suicide occurrences in the city of São Paulo, Brazil. Methods: Data relating to male and female suicides were extracted from the Mortality Information Enhancement Program (PRO-AIM), the official health statistics of the municipality of São Paulo. Seasonality was assessed by studying distribution of suicides over time using cosinor analyses. Results: There were 6,916 registered suicides (76.7% men), with an average of 39.0 ± 7.0 observed suicides per month. For the total sample and for both sexes, cosinor analysis estimated a significant seasonal pattern. For the total sample and for males suicide peaked in November (late spring) with a trough in May–June (late autumn). For females, the estimated peak occurred in January, and the trough in June–July. Conclusions: A seasonal pattern of suicides was found for both males and females, peaking in spring/summer and dipping in fall/winter. The scarcity of reports from intertropical latitudes warrants promoting more studies in this area.

Rorschach-CS Scores of Six Groups of Patients

2013 ◽  
Vol 34 (1) ◽  
pp. 24-55 ◽  
Author(s):  
Caspar C. Berghout ◽  
Jolien Zevalkink ◽  
Abraham N. J. Pieters ◽  
Gregory J. Meyer
Keyword(s):  
Mental Health ◽  
Health Care ◽  
Health Care Organizations ◽  
Total Sample ◽  
Psychoanalytic Psychotherapy ◽  
Cross Sectional ◽  
Treatment Groups ◽  
Treatment Type ◽  
Psychotherapy Groups ◽  
Cross Sectional Design

In this study we used a quasiexperimental, cross-sectional design with six cohorts differing in phase of treatment (pretreatment, posttreatment, 2-year posttreatment) and treatment type (psychoanalysis and psychoanalytic psychotherapy) and investigated scores on 39 Rorschach-CS variables. The total sample consisted of 176 participants from four mental health care organizations in The Netherlands. We first examined pretreatment differences between patients entering psychoanalysis and patients entering psychoanalytic psychotherapy. The two treatment groups did not seem to differ substantially before treatment, with the exception of the level of ideational problems. Next, we studied the outcome of psychoanalysis and psychoanalytic psychotherapy by comparing the Rorschach-CS scores of the six groups of patients. In general, we found significant differences between pretreatment and posttreatment on a relatively small number of Rorschach-CS variables. More pre/post differences were found between the psychoanalytic psychotherapy groups than between the psychoanalysis groups. More research is needed to examine whether analyzing clusters of variables might reveal other results.

Sign in / Sign up

Export Citation Format

Share Document