scholarly journals Novel method for determining <sup>234</sup>U–<sup>238</sup>U ages of Devils Hole 2 cave calcite (Nevada)

Geochronology ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 49-58
Author(s):  
Xianglei Li ◽  
Kathleen A. Wendt ◽  
Yuri Dublyansky ◽  
Gina E. Moseley ◽  
Christoph Spötl ◽  
...  
Keyword(s):  
The Novel ◽  
Time Intervals ◽  
Δ13c Values ◽  
Devils Hole ◽  
Calcite Deposition ◽  
Dating Method ◽  
Novel Method ◽  
Multi Linear Regression ◽  
Δ18o And Δ13c

Abstract. Uranium–uranium (234U–238U) disequilibrium dating can determine the age of secondary carbonates over greater time intervals than the well-established 230Th–234U dating method. Yet it is rarely applied due to unknowns in the initial δ234U (δ234Ui) value, which result in significant age uncertainties. In order to understand the δ234Ui in Devils Hole 2 cave, Nevada, we have determined 110 δ234Ui values from phreatic calcite using 230Th–234U disequilibrium dating. The sampled calcite was deposited in Devils Hole 2 between 4 and 590 ka, providing a long-term look at δ234Ui variability over time. We then performed multi-linear regression among the δ234Ui values and correlative δ18O and δ13C values. The regression can be used to estimate the δ234Ui value of Devils Hole calcite based upon its measured δ18O and δ13C values. Using this approach and the measured present-day δ234U values of Devils Hole 2 calcite, we calculated 110 independent 234U–238U ages. In addition, we used newly measured δ18O, δ13C, and present-day δ234U values to calculate 10 234U–238U ages that range between 676 and 731 ka, thus allowing us to extend the Devils Hole chronology beyond the 230Th–234U-dated chronology while maintaining an age precision of ∼ 2 %. Our results indicate that calcite deposition at Devils Hole 2 cave began no later than 736 ± 11 kyr ago. The novel method presented here may be applied to future speleothem studies in similar hydrogeological settings, given appropriate calibration studies.

Novel method for determining 234U-238U ages of Devils Hole 2 cave calcite (Nevada)

2021 ◽  
Author(s):  
Xianglei Li ◽  
Kathleen A. Wendt ◽  
Yuri Dublyansky ◽  
Gina E. Moseley ◽  
Christoph Spötl ◽  
...  
Keyword(s):  
Linear Regression ◽  
The Novel ◽  
Time Intervals ◽  
Devils Hole ◽  
Calcite Deposition ◽  
Dating Method ◽  
Novel Method ◽  
Multi Linear Regression ◽  
Over Time

&lt;p&gt;Uranium-uranium (&lt;sup&gt;234&lt;/sup&gt;U-&lt;sup&gt;238&lt;/sup&gt;U) disequilibrium dating can determine the age of secondary carbonates over greater time intervals than the well-established &lt;sup&gt;230&lt;/sup&gt;Th-&lt;sup&gt;234&lt;/sup&gt;U dating method. Yet it is rarely applied due to unknowns in the initial d&lt;sup&gt;234&lt;/sup&gt;U (d&lt;sup&gt;234&lt;/sup&gt;U&lt;sub&gt;i&lt;/sub&gt;) value, which result in significant age uncertainties. In order to understand the d&lt;sup&gt;234&lt;/sup&gt;U&lt;sub&gt;i&lt;/sub&gt; in Devils Hole 2 cave, Nevada, we have determined 110 d&lt;sup&gt;234&lt;/sup&gt;U&lt;sub&gt;i&lt;/sub&gt; values from phreatic calcite using &lt;sup&gt;230&lt;/sup&gt;Th-&lt;sup&gt;234&lt;/sup&gt;U disequilibrium dating. The sampled calcite was deposited in Devils Hole 2 between 4 and 590 ka, providing a long-term look at d&lt;sup&gt;234&lt;/sup&gt;U&lt;sub&gt;i&lt;/sub&gt; variability over time. We then performed multi-linear regression among the d&lt;sup&gt;234&lt;/sup&gt;U&lt;sub&gt;i&lt;/sub&gt; values and correlative d&lt;sup&gt;18&lt;/sup&gt;O and d&lt;sup&gt;13&lt;/sup&gt;C values. The regression can be used to estimate the d&lt;sup&gt;234&lt;/sup&gt;U&lt;sub&gt;i&lt;/sub&gt; value of Devils Hole calcite based upon its measured d&lt;sup&gt;18&lt;/sup&gt;O and d&lt;sup&gt;13&lt;/sup&gt;C values. Using this approach and the measured present-day d&lt;sup&gt;234&lt;/sup&gt;U values of Devils Hole 2 calcite, we calculated 110 independent &lt;sup&gt;234&lt;/sup&gt;U-&lt;sup&gt;238&lt;/sup&gt;U ages. In addition, we used newly measured d&lt;sup&gt;18&lt;/sup&gt;O, d&lt;sup&gt;13&lt;/sup&gt;C, and present-day d&lt;sup&gt;234&lt;/sup&gt;U values to calculate 10 &lt;sup&gt;234&lt;/sup&gt;U-&lt;sup&gt;238&lt;/sup&gt;U ages that range between 676 and 731 ka, thus allowing us to extend the Devils Hole chronology beyond the &lt;sup&gt;230&lt;/sup&gt;Th-&lt;sup&gt;234&lt;/sup&gt;U-dated chronology while maintaining an age precision of ~2 %. Our results indicate that calcite deposition at Devils Hole 2 cave began no later than 736 &amp;#177; 11 kyr ago. The novel method presented here may be applied to future speleothem studies in similar hydrogeological settings, given appropriate calibration studies.&lt;/p&gt;

scholarly journals Novel method for determining <sup>234</sup>U-<sup>238</sup>U ages of Devils Hole 2 cave calcite

2020 ◽  
Author(s):  
Xianglei Li ◽  
Kathleen A. Wendt ◽  
Yuri Dublyansky ◽  
Gina E. Moseley ◽  
Christoph Spötl ◽  
...  
Keyword(s):  
The Novel ◽  
Time Intervals ◽  
Devils Hole ◽  
Calcite Deposition ◽  
Dating Method ◽  
Novel Method ◽  
Linear Regressions ◽  
Over Time ◽  
Δ18o And Δ13c

Abstract. Uranium-uranium (234U-238U) dating can determine the age of secondary carbonates over greater time intervals than the well-established 230Th-234U dating method. Yet it is rarely applied due to unknowns surrounding the initial δ234U (δ234Ui) value, which result in significant age uncertainties. In order to understand the δ234Ui in Devils Hole 2 cave, we have precisely determined 110 δ234Ui values from phreatic calcite crusts using a 230Th-234U chronology. The sampled calcite crusts were deposited in Devils Hole 2 between 4 and 590 thousand years, providing a long-term look at δ234Ui variability over time. We then performed multi-linear regressions among the δ234Ui values and correlative δ18O and δ13C values. These regressions allow us to predict the δ234Ui value of Devils Hole calcite based upon its δ18O and δ13C. Using this approach and measured present-day &amp;felta;234U values, we calculate 110 independent 234U-238U ages of Devils Hole 2 cave deposits. In addition, we used newly measured δ18O, δ13C, and present-day δ234U values to calculate 10 234U-238U ages that range between 676 and 731 thousand years, thus allowing us to extend the Devils Hole chronology beyond the 230Th-234U-dated chronology while maintaining an age precision of ~2 %. Our results indicate that calcite deposition at Devils Hole 2 cave began no later than 736 &amp;pm; 11 thousand years ago. The novel method presented here may be used in future speleothem studies in similar hydrogeological settings, given appropriate calibration studies.

scholarly journals Victims of War: Dehydroepiandrosterone Concentrations in Hair and Their Associations with Trauma Sequelae in Palestinian Adolescents Living in the West Bank

2019 ◽  
Vol 9 (2) ◽  
pp. 20 ◽  
Author(s):  
Lena Schindler ◽  
Mohammed Shaheen ◽  
Rotem Saar-Ashkenazy ◽  
Kifah Bani Odeh ◽  
Sophia-Helen Sass ◽  
...  
Keyword(s):  
Traumatic Stress ◽  
West Bank ◽  
The Novel ◽  
The West ◽  
Hair Samples ◽  
Novel Method ◽  
Reported Data ◽  
And Coping ◽  
Trauma Sequelae

Due to its anti-glucocorticoid properties, the steroid hormone dehydroepiandrosterone (DHEA) might play a role for coping with traumatic stress and posttraumatic stress disorder (PTSD). The majority of studies report elevated DHEA secretion and decreased cortisol/DHEA ratio associated with traumatic stress, however, contrasting results have also been published. One reason for this heterogeneity might be that in past studies, DHEA has been measured in plasma or saliva samples reflecting acute hormone levels. In comparison, the current study assessed the hair levels of DHEA and cortisol as long-term markers along with self-reported data on psychopathology and coping in 92 female adolescents aged 11–16 from the West Bank affected by the Israeli–Palestinian conflict. Results showed that trauma-exposed individuals had significantly higher DHEA levels (p = 0.013) and lower cortisol/DHEA ratios (p = 0.036) than participants from the non-trauma group. Furthermore, DHEA and cortisol/DHEA ratio emerged as associated with trauma load and timing, but not with coping. By applying the novel method of DHEA analysis from hair samples, this study adds to the growing literature on the interplay of DHEA, cortisol, traumatic stress and coping, and provides valuable starting points for further research.

scholarly journals Novel Method to Remove Bilirubin from the Blood of Jaundiced Rats: A Preliminary Study

2021 ◽  
Author(s):  
Qiang Lu ◽  
Hong-Fan Ding ◽  
Yong Wan ◽  
Jia-Wei Yu ◽  
Lu Ren ◽  
...  
Keyword(s):  
Histological Examination ◽  
Serum Transaminase ◽  
The Novel ◽  
Novel Therapy ◽  
Term Survival ◽  
Long Term Survival ◽  
Model Animal ◽  
Novel Method

Abstract BACKGROUND The removal of bilirubin from serum is the primary method for treating hyperbilirubinemia. However, currently used treatment methods have several limitations.AIMTo introduce a novel method to remove bilirubin from the blood of jaundiced rats.METHODS This novel therapy involved cross-circulation of blood between a rat liver preserved in vitro and a rat with hyperbilirubinemia. The liver was perfused with blood from the model animal, resulting in the clearance of serum bilirubin. Twenty rats with jaundice caused by acute liver failure induced using D-galactosamine were treated. All model animals were randomly divided into two groups based on whether they received the novel therapy. Serum samples were collected before modelling, at the beginning of treatment, and 2 hours after treatment. The levels of serum transaminase and bilirubin were detected and compared between different time points. Histological examination of the liver in vitro was also performed after the treatment. Long-term survival was compared by Kaplan-Meier analysis between rats who did and did not receive the novel treatment.RESULTSIn vitro, the liver could be perfused with the blood from the model animal through the portal vein. The bile produced by the liver after 1 hour of therapy was darker than the bile produced while harvesting. Across different hyperbilirubinemia models, serum total bilirubin level was significantly improved (24.8 ± 1.2 vs. 17.4 ± 1.2 μmol/L, P<0.05), despite a rise serum transaminase levels after treatment (AST: 4612 ± 382 vs. 5144 ± 390 U/L, P＞0.05; ALT: 5051 ± 722 vs. 5488 ± 707 U/L, P＜0.05). No necrosis was found in the preserved liver tissue after treatment, and the hepatic lobule structure was normal. Hepatocyte necrosis was not found on histological examination. This novel treatment significantly raised the long-term survival rates of jaundiced rats (P <0.05).CONCLUSIONThis novel method could safely and effectively help eliminate bilirubin from the blood of jaundiced rats.

scholarly journals Seasonal variations recorded in cave monitoring results and a 10 year monthly resolved speleothem δ<sup>18</sup>O and δ<sup>13</sup>C record from the Han-sur-Lesse cave, Belgium

2014 ◽  
Vol 10 (2) ◽  
pp. 1821-1856 ◽  
Author(s):  
M. Van Rampelbergh ◽  
S. Verheyden ◽  
M Allan ◽  
Y. Quinif ◽  
E. Keppens ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Water Film ◽  
High Discharge ◽  
Δ13c Values ◽  
Discharge Rates ◽  
Opposite Behavior ◽  
Calcite Deposition ◽  
Cave Monitoring ◽  
Short Time ◽  
Δ18o And Δ13c

Abstract. Speleothems provide paleoclimate information on multi-millennial to decadal scales in the Holocene. However seasonal or even monthly resolved records remain scarce. They require fast growing stalagmites and a good understanding of the proxy transfer function on very short time scales. The Proserpine stalagmite from the Han-sur-Less cave (Belgium) displays seasonal layers of 0.5 to 2 mm thickness that reconstruct paleoclimates at a monthly scale. Through a regular cave monitoring, we acquired a good understanding of how δ18O and δ13C signals in modern calcite reflect climate variations on sub-seasonal scale. Cave parameters vary seasonally in response to the activity of the vegetation cover and outside air temperature. From December to June, the cave remains in "winter-mode". Outside temperatures are cold inducing low cave air and water temperatures. Bio-productivity in the soil is limited leading to low pCO2, higher δ13C composition of the CO2 in the cave air and high discharge due to the inactivity of the plant coverage. From June to December, the cave switches to "summer-mode" and the measured factors display an opposite behavior. The δ18O and δ13C signals of fresh calcite precipitated on glass slabs vary seasonally. Lowest δ18O values occur during the summer-mode when the δ13C values are high. The δ18O composition of the calcite is in equilibrium with the drip water δ18O and display seasonal variations due to changes in the cave air and water temperature. In contrast to the δ18O signal, δ13C values of the calcite precipitated on the glass slabs do not reflect equilibrium conditions. Highest δ13C values occur during summer, when discharge rates are low increasing the evaporation effect on the thin water film covering the stalagmite. This same antithetical behavior of the δ18O vs. the δ13C signals is seen in the monthly resolved speleothem record that covers the period between 1976 and 1985 AD. Dark layers are formed during summer, while light layers are formed during winter when calcite deposition occurs fast. The darker the color of a layer, the more compact its calcite structure, the more negative its δ18O signal and the more positive its δ13C signal.

scholarly journals AUTOMATED LONG-TERM POLYSOMNOGRAPHY ANALYSIS WITH WAVELET PROCESSING AND ADAPTIVE FUZZY CLUSTERING

2006 ◽  
Vol 18 (03) ◽  
pp. 119-123
Author(s):  
CHIH-FENG CHAO ◽  
JOE-AIR JIANG ◽  
MING-JANG CHIU ◽  
REN-GUEY LEE
Keyword(s):  
Fuzzy Clustering ◽  
Adaptive Method ◽  
Optimal Number ◽  
The Novel ◽  
Individual Subject ◽  
Adaptive Fuzzy ◽  
Novel Method ◽  
Effective Visualization ◽  
Optimal Number Of Clusters

To assist in the inspection of sleep-related diagnosis and research, an adaptive method for processing long-term polysomnography (PSG) is proposed in this paper. The extracted features of segmented PSG based on wavelet analysis can be used for clustering the segments with similar pattern into a group. The adaptive fuzzy clustering was used to estimate the clusters within the PSG recordings, the optimal number of clusters and the optimal features of an individual subject. The novel method with the adaptive-to-subject concept exhibits four advantages in comparison with other approaches: (1) Full automated, (2) adaptive to the diversity of physiological signals among subjects, (3) less sensitive to noise and artifacts, (4) effective visualization of analysis results for clinicians. The simulation results show the superiority of the proposed method in long-term PSG analysis.

A novel method for the determination of linting propensity of paper

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 9-17
Author(s):  
ALESSANDRA GERLI ◽  
LEENDERT C. EIGENBROOD
Keyword(s):  
Ash Content ◽  
The Novel ◽  
Offset Printing ◽  
Excellent Correlation ◽  
End Conditions ◽  
Bottom Side ◽  
Novel Method ◽  
Total Fraction

A novel method was developed for the determination of linting propensity of paper based on printing with an IGT printability tester and image analysis of the printed strips. On average, the total fraction of the surface removed as lint during printing is 0.01%-0.1%. This value is lower than those reported in most laboratory printing tests, and more representative of commercial offset printing applications. Newsprint paper produced on a roll/blade former machine was evaluated for linting propensity using the novel method and also printed on a commercial coldset offset press. Laboratory and commercial printing results matched well, showing that linting was higher for the bottom side of paper than for the top side, and that linting could be reduced on both sides by application of a dry-strength additive. In a second case study, varying wet-end conditions were used on a hybrid former machine to produce four paper reels, with the goal of matching the low linting propensity of the paper produced on a machine with gap former configuration. We found that the retention program, by improving fiber fines retention, substantially reduced the linting propensity of the paper produced on the hybrid former machine. The papers were also printed on a commercial coldset offset press. An excellent correlation was found between the total lint area removed from the bottom side of the paper samples during laboratory printing and lint collected on halftone areas of the first upper printing unit after 45000 copies. Finally, the method was applied to determine the linting propensity of highly filled supercalendered paper produced on a hybrid former machine. In this case, the linting propensity of the bottom side of paper correlated with its ash content.

Concussion in sports in children and adolescents – to play or not to play?

2017 ◽  
Vol 65 (3) ◽  
Keyword(s):  
Gender Differences ◽  
Children And Adolescents ◽  
Return To Sport ◽  
Consensus Conference ◽  
Return To School ◽  
The Novel ◽  
International Consensus ◽  
Persistent Symptoms ◽  
New Findings

A lot has been published on the topic concussion in sports during the last years, conscience was sharpened, much was structured and defined more precisely, help tools were developed and rules changed. This article summarizes the fifth edition of the recently published guidelines of the “International Consensus Conference on Concussion in Sport”. In addition, new findings regarding gender differences and recovery will be presented, as well as the modified “return-to-sport” and the novel “return-to-school” protocols. Despite increased knowledge many questions remain such as the therapy of persistent symptoms or long-term sequelae of recurrent concussions.

scholarly journals Waning antibody responses in COVID-19: what can we learn from the analysis of other coronaviruses?

Infection ◽  
2021 ◽  
Author(s):  
Ali Hamady ◽  
JinJu Lee ◽  
Zuzanna A. Loboda
Keyword(s):  
Cross Reactivity ◽  
Antibody Responses ◽  
The Novel ◽  
Incidence And Mortality ◽  
Antibody Titres ◽  
Human Coronaviruses ◽  
Public Health Strategies ◽  
Antibody Dynamics

Abstract Objectives The coronavirus disease 2019 (COVID-19), caused by the novel betacoronavirus severe acute respiratory syndrome 2 (SARS-CoV-2), was declared a pandemic in March 2020. Due to the continuing surge in incidence and mortality globally, determining whether protective, long-term immunity develops after initial infection or vaccination has become critical. Methods/Results In this narrative review, we evaluate the latest understanding of antibody-mediated immunity to SARS-CoV-2 and to other coronaviruses (SARS-CoV, Middle East respiratory syndrome coronavirus and the four endemic human coronaviruses) in order to predict the consequences of antibody waning on long-term immunity against SARS-CoV-2. We summarise their antibody dynamics, including the potential effects of cross-reactivity and antibody waning on vaccination and other public health strategies. At present, based on our comparison with other coronaviruses we estimate that natural antibody-mediated protection for SARS-CoV-2 is likely to last for 1–2 years and therefore, if vaccine-induced antibodies follow a similar course, booster doses may be required. However, other factors such as memory B- and T-cells and new viral strains will also affect the duration of both natural and vaccine-mediated immunity. Conclusion Overall, antibody titres required for protection are yet to be established and inaccuracies of serological methods may be affecting this. We expect that with standardisation of serological testing and studies with longer follow-up, the implications of antibody waning will become clearer.

scholarly journals Long-Term Experimental Evolution in Escherichia coli. IV. Targets of Selection and the Specificity of Adaptation

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Michael Travisano ◽  
Richard E Lenski
Keyword(s):  
Escherichia Coli ◽  
Experimental Evolution ◽  
Common Ancestor ◽  
The Novel ◽  
Physiological Mechanisms ◽  
Outer Membranes ◽  
Limiting Nutrient ◽  
Novel Environments ◽  
Uptake Mechanisms

Abstract This study investigates the physiological manifestation of adaptive evolutionary change in 12 replicate populations of Escherichia coli that were propagated for 2000 generations in a glucose-limited environment. Representative genotypes from each population were assayed for fitness relative to their common ancestor in the experimental glucose environment and in 11 novel single-nutrient environments. After 2000 generations, the 12 derived genotypes had diverged into at least six distinct phenotypic classes. The nutrients were classified into four groups based upon their uptake physiology. All 12 derived genotypes improved in fitness by similar amounts in the glucose environment, and this pattern of parallel fitness gains was also seen in those novel environments where the limiting nutrient shared uptake mechanisms with glucose. Fitness showed little or no consistent improvement, but much greater genetic variation, in novel environments where the limiting nutrient differed from glucose in its uptake mechanisms. This pattern of fitness variation in the novel nutrient environments suggests that the independently derived genotypes adapted to the glucose environment by similar, but not identical, changes in the physiological mechanisms for moving glucose across both the inner and outer membranes.

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