New Single-Year Radiocarbon Measurements Based on Danish oak Covering the Periods AD 692–790 and 966–1057

Radiocarbon ◽  
2019 ◽  
Vol 62 (4) ◽  
pp. 969-987 ◽  
Author(s):  
Sabrina G K Kudsk ◽  
Bente Philippsen ◽  
Claudia Baittinger ◽  
Alexandra Fogtmann-Schulz ◽  
Mads F Knudsen ◽  
...  
Keyword(s):  
Tree Rings ◽  
Calibration Curve ◽  
Cosmic Ray ◽  
Relevant Information ◽  
The Past ◽  
One Year

ABSTRACTSingle-year measurements of radiocarbon (14C) in tree rings have led to the discovery of rapid cosmic-ray events as well as longer lasting anomalies, which have given new insights into the Sun’s behavior in the past. Here, we present two new single-year 14C records based on Danish oak that span the periods AD 692–790 and 966–1057, respectively, and consequently include the two rapid cosmic-ray events in AD 775 and 994. The new data are presented along with relevant information on the dendrochronological dating of the wood pieces, implying that these new measurements may contribute towards generating the next international calibration curve. The new data covering the AD 966–1057 period suggest that the increase in atmospheric 14C associated with the cosmic-ray event in AD 994 actually occurred in AD 993, i.e. one year earlier than the year reported in Fogtmann-Schulz et al. (2017) based on oak from southern Denmark. Careful reanalysis of the dendrochronology that underpins the new 14C records based on oak material from southern Denmark reveals that the cosmic-ray event reported in Fogtmann-Schulz et al. (2017) actually took place in AD 993.

scholarly journals Theoretical and Experimental Aspects of Solar Flares Manifestation in Radiocarbon Abundance in Tree Rings

Radiocarbon ◽  
1992 ◽  
Vol 34 (2) ◽  
pp. 247-253 ◽  
Author(s):  
A. N. Kostantinov ◽  
V. A. Levchenko ◽  
G. E. Kocharov ◽  
I. B. Mikheeva ◽  
Stefano Cecchini ◽  
...  
Keyword(s):  
Tree Rings ◽  
Solar Flares ◽  
High Probability ◽  
Cosmic Ray ◽  
Cosmogenic Isotopes ◽  
The Past ◽  
Cosmic Ray Flux ◽  
Several Intervals

We describe our method of determining solar cosmic-ray flux and spectrum in the past, based on the comparison of different cosmogenic isotopes. For the period, AD 1781–1950, we have detected several intervals with a high probability of powerful solar flares.

What Is the Carbon Origin of Early-Wood?

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1457-1464 ◽  
Author(s):  
Sabrina G K Kudsk ◽  
Jesper Olsen ◽  
Lasse N Nielsen ◽  
Alexandra Fogtmann-Schulz ◽  
Mads F Knudsen ◽  
...  
Keyword(s):  
Least Squares ◽  
Tree Ring ◽  
Tree Rings ◽  
Time Resolution ◽  
Calibration Curve ◽  
Cosmic Ray ◽  
Annual Variations ◽  
Late Wood ◽  
Annual Scale

ABSTRACTSubstantial amounts of annual radiocarbon (14C) data have recently been produced with the purpose of increasing the time resolution of 14C records used for constructing the calibration curve and for studying the occurrence of abrupt cosmic-ray events. In this study, we investigate if it is possible to resolve sub-annual scale changes in the atmospheric 14C content by measuring radiocarbon in early-wood and late-wood fractions from Danish oak. The tree-ring samples span the period 1954–1970 CE, hereby covering the peak of the bomb pulse. A least squares test comparing the atmospheric 14C content and the new sub-annual 14C record from Danish tree rings reveals that by measuring early-wood and late-wood fractions, it may be possible to resolve sub-annual variations in past atmospheric 14C levels.

scholarly journals Large14C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene

2017 ◽  
Vol 114 (5) ◽  
pp. 881-884 ◽  
Author(s):  
Fusa Miyake ◽  
A. J. Timothy Jull ◽  
Irina P. Panyushkina ◽  
Lukas Wacker ◽  
Matthew Salzer ◽  
...  
Keyword(s):  
Tree Rings ◽  
Time Resolution ◽  
Solar Minimum ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Pine Tree ◽  
Unknown Phase ◽  
Increase Rate ◽  
Bristlecone Pine

Radiocarbon content in tree rings can be an excellent proxy of the past incoming cosmic ray intensities to Earth. Although such past cosmic ray variations have been studied by measurements of14C contents in tree rings with ≥10-y time resolution for the Holocene, there are few annual14C data. There is a little understanding about annual14C variations in the past, with the exception of a few periods including the AD 774−77514C excursion where annual measurements have been performed. Here, we report the result of14C measurements using the bristlecone pine tree rings for the period from 5490 BC to 5411 BC with 1- to 2-y resolution, and a finding of an extraordinarily large14C increase (20‰) from 5481 BC to 5471 BC (the 5480 BC event). The14C increase rate of this event is much larger than that of the normal grand solar minima. We propose the possible causes of this event are an unknown phase of grand solar minimum, or a combination of successive solar proton events and a normal grand solar minimum.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

Tax-Advantaged Trust Use Among IPO Executives: Determinants and Implications for Valuation and Future Performance

2019 ◽  
Vol 95 (3) ◽  
pp. 145-175 ◽  
Author(s):  
Michael J. Dambra ◽  
Matthew Gustafson ◽  
Phillip J. Quinn
Keyword(s):  
Stock Price ◽  
Relevant Information ◽  
Data Availability ◽  
Market Prices ◽  
The Public ◽  
Future Performance ◽  
Estate Taxes ◽  
Price Appreciation ◽  
One Year ◽  
Jel Classifications

ABSTRACT We examine the prevalence and determinants of CEOs' use of tax-advantaged trusts prior to their firm's IPO. Twenty-three percent of CEOs use tax-advantaged pre-IPO trusts, and share transfers into tax-advantaged trusts are positively associated with CEO equity wealth, estate taxes, and dynastic preferences. We project that pre-IPO trust use increases CEOs' dynastic wealth by approximately $830,000, on average. We next examine a simple model's prediction that trust use will be positively related to IPO-period stock price appreciation. We find that trust use is associated with 12 percent higher one-year post-IPO returns, but is not significantly related to the IPO's valuation, filing price revision, or underpricing. This evidence is consistent with CEOs' personal finance decisions prior to the IPO containing value-relevant information that is not immediately incorporated into market prices. JEL Classifications: D14; G12; G32; M21; M41. Data Availability: Data are available from the public sources cited in the text.

scholarly journals Calibration of Radiocarbon Dates for the Late Pleistocene Using U/Th Dates on Stalagmites

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-32 ◽  
Author(s):  
John C. Vogel ◽  
Joel Kronfeld
Keyword(s):  
South Africa ◽  
Magnetic Dipole ◽  
Satisfactory Agreement ◽  
Late Pleistocene ◽  
Calibration Curve ◽  
Dipole Field ◽  
Radiocarbon Dates ◽  
The Past ◽  
The Earth ◽  
Magnetic Dipole Field

Twenty paired 14C and U/Th dates covering most of the past 50,000 yr have been obtained on a stalagmite from the Cango Caves in South Africa as well as some additional age-pairs on two stalagmites from Tasmania that partially fill a gap between 7 ka and 17 ka ago. After allowance is made for the initial apparent 14C ages, the age-pairs between 7 ka and 20 ka show satisfactory agreement with the coral data of Bard et al. (1990, 1993). The results for the Cango stalagmite between 25 ka and 50 ka show the 14C dates to be substantially younger than the U/Th dates except at 49 ka and 29 ka, where near correspondence occurs. The discrepancies may be explained by variations in 14C production caused by changes in the magnetic dipole field of the Earth. A tentative calibration curve for this period is offered.

scholarly journals Hepatitis and tuberculosis testing are much less common than HIV testing among adults in Kisumu, Kenya: results from a cross-sectional assessment

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Joshua Tunnage ◽  
Adam Yates ◽  
Chiaka Nwoga ◽  
Valentine Sing’oei ◽  
John Owuoth ◽  
...  
Keyword(s):  
Secondary Education ◽  
Viral Hepatitis ◽  
Hiv Testing ◽  
Spatial Location ◽  
Tuberculosis Screening ◽  
Cross Sectional ◽  
The Past ◽  
Prior Testing ◽  
Testing Uptake ◽  
One Year

Abstract Background Kenya has a high burden of HIV, viral hepatitis, and tuberculosis. Screening is necessary for early diagnosis and treatment, which reduces morbidity and mortality across all three illnesses. We evaluated testing uptake for HIV, viral hepatitis, and tuberculosis in Kisumu, Kenya. Methods Cross-sectional data from adults aged 18–35 years who enrolled in a prospective HIV incidence cohort study from February 2017 to May 2018 were analyzed. A questionnaire was administered to each participant at screening for study eligibility to collect behavioral characteristics and to assess prior testing practices. Among participants without a history of previously-diagnosed HIV, multivariable robust Poisson regression was used to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for factors potentially associated with HIV testing in the 12 months prior to enrollment. A hierarchical model was used to test for differential access to testing due to spatial location. Results Of 671 participants, 52 (7.7%) were living with HIV, 308 (45.9%) were female, and the median age was 24 (interquartile range 21–28) years. Among 651 (97.0%) who had ever been tested for HIV, 400 (61.2%) reported HIV testing in the past 6 months, 129 (19.7%) in the past 6–12 months, and 125 (19.1%) more than one year prior to enrollment. Any prior testing for viral hepatitis was reported by 8 (1.2%) participants and for tuberculosis by 51 (7.6%). In unadjusted models, HIV testing in the past year was more common among females (PR 1.08 [95% CI 1.01, 1.17]) and participants with secondary education or higher (PR 1.10 [95% CI 1.02, 1.19]). In the multivariable model, only secondary education or higher was associated with recent HIV testing (adjusted PR 1.10 [95% CI 1.02, 1.20]). Hierarchical models showed no geographic differences in HIV testing across Kisumu subcounties. Conclusions Prior HIV testing was common among study participants and most had been tested within the past year but testing for tuberculosis and viral hepatitis was far less common. HIV testing gaps exist for males and those with lower levels of education. HIV testing infrastructure could be leveraged to increase access to testing for other endemic infectious diseases.

scholarly journals Impact of Coronavirus Outbreaks on Science and Society: Insights from Temporal Bibliometry of SARS and COVID-19

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 626
Author(s):  
Ramya Gupta ◽  
Abhishek Prasad ◽  
Suresh Babu ◽  
Gitanjali Yadav
Keyword(s):  
Published Data ◽  
Science And Society ◽  
Time Dimension ◽  
Scientific Publications ◽  
The Past ◽  
Economic Trends ◽  
Global Events ◽  
One Year ◽  
Personal Devices ◽  
Share Information

A global event such as the COVID-19 crisis presents new, often unexpected responses that are fascinating to investigate from both scientific and social standpoints. Despite several documented similarities, the coronavirus pandemic is clearly distinct from the 1918 flu pandemic in terms of our exponentially increased, almost instantaneous ability to access/share information, offering an unprecedented opportunity to visualise rippling effects of global events across space and time. Personal devices provide “big data” on people’s movement, the environment and economic trends, while access to the unprecedented flurry in scientific publications and media posts provides a measure of the response of the educated world to the crisis. Most bibliometric (co-authorship, co-citation, or bibliographic coupling) analyses ignore the time dimension, but COVID-19 has made it possible to perform a detailed temporal investigation into the pandemic. Here, we report a comprehensive network analysis based on more than 20,000 published documents on viral epidemics, authored by over 75,000 individuals from 140 nations in the past one year of the crisis. Unlike the 1918 flu pandemic, access to published data over the past two decades enabled a comparison of publishing trends between the ongoing COVID-19 pandemic and those of the 2003 SARS epidemic to study changes in thematic foci and societal pressures dictating research over the course of a crisis.

scholarly journals One Year of the COVID-19 Pandemic in Galicia: A Global View of Age-Group Statistics during Three Waves

2021 ◽  
Vol 18 (10) ◽  
pp. 5104
Author(s):  
Iván Area ◽  
Henrique Lorenzo ◽  
Pedro J. Marcos ◽  
Juan J. Nieto
Keyword(s):  
Intensive Care Unit ◽  
Hospital Admissions ◽  
Age Groups ◽  
Age Group ◽  
Nw Spain ◽  
The Past ◽  
Global View ◽  
Time Period ◽  
Key Variables ◽  
One Year

In this work we look at the past in order to analyze four key variables after one year of the COVID-19 pandemic in Galicia (NW Spain): new infected, hospital admissions, intensive care unit admissions and deceased. The analysis is presented by age group, comparing at each stage the percentage of the corresponding group with its representation in the society. The time period analyzed covers 1 March 2020 to 1 April 2021, and includes the influence of the B.1.1.7 lineage of COVID-19 which in April 2021 was behind 90% of new cases in Galicia. It is numerically shown how the pandemic affects the age groups 80+, 70+ and 60+, and therefore we give information about how the vaccination process could be scheduled and hints at why the pandemic had different effects in different territories.

Public Policy Administration

1985 ◽  
Vol 47 ◽  
pp. 1-16
Author(s):  
Richard A. Brumback
Keyword(s):  
Rhode Island ◽  
General Level ◽  
American Government ◽  
Introductory Course ◽  
The Past ◽  
Business Colleges ◽  
Business College ◽  
Large Numbers ◽  
The Subject ◽  
One Year

The teaching of an introductory course in American Government can be a difficult and frustrating endeavor under even the best of circumstances. Given the general level of cynicism and/or lack of interest by large numbers of Americans regarding politics and politicians, the task of generating student enthusiasm, or even mild interest, toward the subject matter can indeed be an arduous one. When the teaching of such a course takes place in a business college, and when the student audience is “captive” to a college requirement that all students must take the course, the task can be rendered considerably more formidable.For the past six years I have been teaching such courses at business colleges — one year at Bryant College in Rhode Island, and the following five years at Bentley College in Massachusetts.

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