scholarly journals Precision Calendar-Year Dating of the Elm Decline in a Sphagnum-Peat Bog in Southern Sweden

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 197-202 ◽  
Author(s):  
Göran Skog ◽  
Joachim Regnéll
Keyword(s):  
High Resolution ◽  
High Precision ◽  
Pollen Analysis ◽  
Calibration Curve ◽  
Peat Bog ◽  
Southern Sweden ◽  
Sphagnum Peat

The cause of the mid-Holocene elm decline in northwestern Europe and its relation to the contemporaneous transition from Mesolithic to Neolithic economy are still unclear, partly owing to the lack of a precise, calibrated chronology. Matching of a sequence of 14C dates to the calibration curve in combination with accurate 14C dating allows high-precision dating of paleoecological events. We have completed high-resolution dating of a Sphagnum-peat sequence from Ageröds Mosse in southernmost Sweden. The basis for selecting 14C samples was pollen analysis at 1 cm intervals. Nine 14C dates, covering an interval of ca. 500 calendar years around the elm decline, showed that this event occurred in Ageröds Mosse within a few decades ca. 3770 bc.

scholarly journals Fluctuating radiocarbon offsets observed in the southern Levant and implications for archaeological chronology debates

2018 ◽  
Vol 115 (24) ◽  
pp. 6141-6146 ◽  
Author(s):  
Sturt W. Manning ◽  
Carol Griggs ◽  
Brita Lorentzen ◽  
Christopher Bronk Ramsey ◽  
David Chivall ◽  
...  
Keyword(s):  
High Resolution ◽  
Northern Hemisphere ◽  
High Precision ◽  
Tree Rings ◽  
Iron Age ◽  
Calibration Curve ◽  
Southern Levant ◽  
Current Standard ◽  
Considerable Work

Considerable work has gone into developing high-precision radiocarbon (14C) chronologies for the southern Levant region during the Late Bronze to Iron Age/early Biblical periods (∼1200–600 BC), but there has been little consideration whether the current standard Northern Hemisphere14C calibration curve (IntCal13) is appropriate for this region. We measured14C ages of calendar-dated tree rings from AD 1610 to 1940 from southern Jordan to investigate contemporary14C levels and to compare these with IntCal13. Our data reveal an average offset of ∼1914C years, but, more interestingly, this offset seems to vary in importance through time. While relatively small, such an offset has substantial relevance to high-resolution14C chronologies for the southern Levant, both archaeological and paleoenvironmental. For example, reconsidering two published studies, we find differences, on average, of 60% between the 95.4% probability ranges determined from IntCal13 versus those approximately allowing for the observed offset pattern. Such differences affect, and even potentially undermine, several current archaeological and historical positions and controversies.

A new method for TIMS high precision analysis of Ba and Sr isotopes for cosmochemical studies

2017 ◽  
Vol 32 (7) ◽  
pp. 1388-1399 ◽  
Author(s):  
Elsa Yobregat ◽  
Caroline Fitoussi ◽  
Bernard Bourdon
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Precision ◽  
Thermal Ionization Mass Spectrometry ◽  
New Method ◽  
Ionization Mass ◽  
Sr Isotopes ◽  
Sr Resin ◽  
Thermal Ionization Mass ◽  
Isotope Measurements

A new protocol using Eichron™ Sr-resin for high-resolution Sr and Ba isotope measurements using thermal ionization mass spectrometry for cosmochemical samples.

High-Resolution Age-Depth Model of a Peat Bog in Poland as an Important Basis for Paleoenvironmental Studies

Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 109-125 ◽  
Author(s):  
B Fiałkiewicz-Kozieł ◽  
P Kołaczek ◽  
N Piotrowska ◽  
A Michczyński ◽  
E Łokas ◽  
...  
Keyword(s):  
High Resolution ◽  
Industrial Revolution ◽  
Climatic Factors ◽  
Accumulation Rate ◽  
Bulk Composition ◽  
Water Level Fluctuations ◽  
Peat Bog ◽  
Agricultural Activity ◽  
Peat Accumulation ◽  
Peat Formation

This article focuses on constructing a high-resolution age-depth model for the Puścizna Mała peat bog located in Orawa-Nowy Targ Basin (S Poland). The chronology was established on the basis of both210Pb and14C measurements, and further confirmed by pollen diagrams and the peat bulk composition (density, ash content, and measurements of C, N, S). The137Cs profile revealed significant downward migration of this radionuclide and was not suitable for geochronological interpretation. The peat profile in southern Poland records almost 2000 yr of paleoecological and geochemical changes. Major historical events linked to anthropogenic and climatic changes are recorded in the investigated proxies, which confirm the reliability of the age-depth model. Specifically, the Roman period, Migration period, Medieval times, as well as the Industrial Revolution are reflected in the palynology and bulk composition of the peat. However, dating results obtained for the core segment between 22–45 cm are problematic when confronted with other analyses. The highest peat accumulation rate of 2 mm yr-1(AD 1300–1400 according to the age-depth model) is not compatible with the section of the highest peat decomposition revealed by lithological description. Moreover, the onset of a drastic decline of forests reflected in the palynological data and dated to AD 1280–1340 (40 cm) is difficult to explain in the light of historical data. Therefore, the lithology, bulk density, and pollen were used to validate the obtained age-depth model. External forcing factors on the peat formation process may be indicated, including agricultural activity, water-level fluctuations, and natural climatic factors, which paradoxically caused doubling of the obtained peat accumulation rate.

scholarly journals High-precision 41K/39K measurements by MC-ICP-MS indicate terrestrial variability of δ41K

2018 ◽  
Vol 33 (2) ◽  
pp. 175-186 ◽  
Author(s):  
Leah E. Morgan ◽  
Danielle P. Santiago Ramos ◽  
Brett Davidheiser-Kroll ◽  
John Faithfull ◽  
Nicholas S. Lloyd ◽  
...  
Keyword(s):  
High Resolution ◽  
High Precision ◽  
Cold Plasma ◽  
Isotopic Compositions ◽  
Icp Ms

Potassium isotopic compositions measured by MC-ICP-MS in cold-plasma, high-resolution mode indicate terrestrial variability in 41K/39K ratios.

The performance comparison of typical notched flexure hinges

2019 ◽  
Vol 234 (9) ◽  
pp. 1859-1867
Author(s):  
Wei Ma ◽  
Rongqi Wang ◽  
Xiaoqin Zhou ◽  
Guangwei Meng
Keyword(s):  
High Resolution ◽  
High Precision ◽  
Compliant Mechanisms ◽  
Performance Comparison ◽  
Modeling Method ◽  
Stress Concentrations ◽  
High Demand ◽  
Flexure Hinges ◽  
Matrix Modeling ◽  
Practical Guidelines

Flexure hinges, which serve as the crucial joints in a large number of compliant mechanisms, have been widely applied in a variety of significant fields where there is high demand for the micro/nano motions with high resolution and high precision. Currently, an increasing number of notched flexure hinges with different structures and performances have been rapidly developed, but the existing performance comparisons on different notched flexure hinges were only conducted on seldom typical structures and are far from the comprehensiveness and fairness due to the different comparative conditions and discrepant evaluating indexes. Therefore, the finite beam-based matrix modeling method and nondimension precision factors will be employed in comprehensive comparing and ranking of 13 types of frequently-used notched flexure hinges in terms of their main compliances, motion accuracies, and stress concentrations, further providing useful practical guidelines to develop the compliant mechanisms with excellent overall performances.

scholarly journals ACF Based Region Proposal Extraction for YOLOv3 Network Towards High-Performance Cyclist Detection in High Resolution Images

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2671 ◽  
Author(s):  
Chunsheng Liu ◽  
Yu Guo ◽  
Shuang Li ◽  
Faliang Chang
Keyword(s):  
High Resolution ◽  
High Precision ◽  
Extraction Method ◽  
High Performance ◽  
Detection Methods ◽  
Average Precision ◽  
Deep Network ◽  
High Resolution Images ◽  
Bounding Boxes ◽  
Detection And Localization

You Only Look Once (YOLO) deep network can detect objects quickly with high precision and has been successfully applied in many detection problems. The main shortcoming of YOLO network is that YOLO network usually cannot achieve high precision when dealing with small-size object detection in high resolution images. To overcome this problem, we propose an effective region proposal extraction method for YOLO network to constitute an entire detection structure named ACF-PR-YOLO, and take the cyclist detection problem to show our methods. Instead of directly using the generated region proposals for classification or regression like most region proposal methods do, we generate large-size potential regions containing objects for the following deep network. The proposed ACF-PR-YOLO structure includes three main parts. Firstly, a region proposal extraction method based on aggregated channel feature (ACF) is proposed, called ACF based region proposal (ACF-PR) method. In ACF-PR, ACF is firstly utilized to fast extract candidates and then a bounding boxes merging and extending method is designed to merge the bounding boxes into correct region proposals for the following YOLO net. Secondly, we design suitable YOLO net for fine detection in the region proposals generated by ACF-PR. Lastly, we design a post-processing step, in which the results of YOLO net are mapped into the original image outputting the detection and localization results. Experiments performed on the Tsinghua-Daimler Cyclist Benchmark with high resolution images and complex scenes show that the proposed method outperforms the other tested representative detection methods in average precision, and that it outperforms YOLOv3 by 13.69 % average precision and outperforms SSD by 25.27 % average precision.

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