scholarly journals REASSESSMENT OF UNCERTAINTY EXPANSION BY LINEAR ADDITION OF LONG-TERM COMPONENTS FROM TOP-DOWN INFORMATION

Radiocarbon ◽  
2021 ◽  
pp. 1-15
Author(s):  
G Salazar ◽  
S Szidat
Keyword(s):  
Mass Spectrometry ◽  
Measurement Uncertainty ◽  
High Precision ◽  
Accelerator Mass Spectrometry ◽  
Expanded Uncertainty ◽  
Top Down ◽  
Bottom Up ◽  
Linear Addition

ABSTRACT Since radiocarbon accelerator mass spectrometry (14C AMS) is considered a high-precision technique, reassessment of the measurement uncertainty has been a topic of interest. Scientists from analytical and metrological fields have developed the top-down and bottom-up measurement of uncertainty approaches. The 14C quoted error should approximate the uncertainty of long-term repetitions of the top-down approach in order to be realistic. The novelty of this paper is that the uncertainty of both approaches were approximated to each other. Furthermore, we apportioned the graphitization, instrumentation, and bias components in order to additively expand the quoted error. Our results are comparable to error multipliers and to long-term repeatability studies reported by other laboratories. Our laboratory was established in late 2012 with N2 as stripper gas and 7 years later, we changed to helium stripper. Thus, we were able to compare both gases, and demonstrate that helium is a better stripper gas. In absolute F14C units, the ranges of graphitization+bias combined uncertainties were (0.7 to 4.1) × 10–3 for N2 and (0.7–3.0) × 10–3 for He depending on the standard 14C content. The error multiplier for He defined as the expanded uncertainty over quoted error, in average, was 1.7; while without the bias, the multiplier was 1.3.

scholarly journals Findings from an in-Depth Annual Tree-Ring Radiocarbon Intercomparison

Radiocarbon ◽  
2020 ◽  
Vol 62 (4) ◽  
pp. 873-882 ◽  
Author(s):  
L Wacker ◽  
E M Scott ◽  
A Bayliss ◽  
D Brown ◽  
E Bard ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tree Ring ◽  
High Precision ◽  
Calibration Curve ◽  
Accelerator Mass Spectrometry ◽  
Large Datasets ◽  
Accuracy And Precision ◽  
Short Period ◽  
Annual Resolution

ABSTRACTThe radiocarbon (14C) calibration curve so far contains annually resolved data only for a short period of time. With accelerator mass spectrometry (AMS) matching the precision of decay counting, it is now possible to efficiently produce large datasets of annual resolution for calibration purposes using small amounts of wood. The radiocarbon intercomparison on single-year tree-ring samples presented here is the first to investigate specifically possible offsets between AMS laboratories at high precision. The results show that AMS laboratories are capable of measuring samples of Holocene age with an accuracy and precision that is comparable or even goes beyond what is possible with decay counting, even though they require a thousand times less wood. It also shows that not all AMS laboratories always produce results that are consistent with their stated uncertainties. The long-term benefits of studies of this kind are more accurate radiocarbon measurements with, in the future, better quantified uncertainties.

scholarly journals Mass spectrometry‐based top‐down and bottom‐up approaches for proteomic analysis of the Moroccan Buthus occitanus scorpion venom

FEBS Open Bio ◽  
2021 ◽  
Author(s):  
Khadija Daoudi ◽  
Christian Malosse ◽  
Ayoub Lafnoune ◽  
Bouchra Darkaoui ◽  
Salma Chakir ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Proteomic Analysis ◽  
Scorpion Venom ◽  
Top Down ◽  
Bottom Up

scholarly journals THE BEGINNING OF THE IRON AGE AT ARSLANTEPE: A 14C PERSPECTIVE

Radiocarbon ◽  
2021 ◽  
pp. 1-19
Author(s):  
Federico Manuelli ◽  
Cristiano Vignola ◽  
Fabio Marzaioli ◽  
Isabella Passariello ◽  
Filippo Terrasi
Keyword(s):  
Mass Spectrometry ◽  
Bronze Age ◽  
High Precision ◽  
Iron Age ◽  
Accelerator Mass Spectrometry ◽  
Late Bronze Age ◽  
13Th Century ◽  
Historical Events ◽  
Preliminary Results ◽  
Archaeological Data

ABSTRACT The Iron Age chronology at Arslantepe is the result of the interpretation of Luwian hieroglyphic inscriptions and archaeological data coming from the site and its surrounding region. A new round of investigations of the Iron Age levels has been conducted at the site over the last 10 years. Preliminary results allowed the combination of the archaeological sequence with the historical events that extended from the collapse of the Late Bronze Age empires to the formation and development of the new Iron Age kingdoms. The integration into this picture of a new set of radiocarbon (14C) dates is aimed at establishing a more solid local chronology. High precision 14C dating by accelerator mass spectrometry (AMS) and its correlation with archaeobotanical analysis and stratigraphic data are presented here with the purpose of improving our knowledge of the site’s history and to build a reliable absolute chronology of the Iron Age. The results show that the earliest level of the sequence dates to ca. the mid-13th century BC, implying that the site started developing a new set of relationships with the Levant already before the breakdown of the Hittite empire, entailing important historical implications for the Syro-Anatolian region at the end of the 2nd millennium BC.

scholarly journals Quality Dating: A Well-Defined Protocol Implemented at ETH for High-Precision 14C-Dates Tested on Late Glacial Wood

Radiocarbon ◽  
2019 ◽  
Vol 62 (4) ◽  
pp. 891-899 ◽  
Author(s):  
Adam Sookdeo ◽  
Bernd Kromer ◽  
Ulf Büntgen ◽  
Michael Friedrich ◽  
Ronny Friedrich ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tree Ring ◽  
High Precision ◽  
Accelerator Mass Spectrometry ◽  
Late Glacial ◽  
Tree Ring Chronology ◽  
Continuous Measurements ◽  
Calibration Curves

ABSTRACTAdvances in accelerator mass spectrometry have resulted in an unprecedented amount of new high-precision radiocarbon (14C) -dates, some of which will redefine the international 14C calibration curves (IntCal and SHCal). Often these datasets are unaccompanied by detailed quality insurances in place at the laboratory, questioning whether the 14C structure is real, a result of a laboratory variation or measurement-scatter. A handful of intercomparison studies attempt to elucidate laboratory offsets but may fail to identify measurement-scatter and are often financially constrained. Here we introduce a protocol, called Quality Dating, implemented at ETH-Zürich to ensure reproducible and accurate high-precision 14C-dates. The protocol highlights the importance of the continuous measurements and evaluation of blanks, standards, references and replicates. This protocol is tested on an absolutely dated German Late Glacial tree-ring chronology, part of which is intercompared with the Curt Engelhorn-Center for Archaeometry, Mannheim, Germany (CEZA). The combined dataset contains 170 highly resolved, highly precise 14C-dates that supplement three decadal dates spanning 280 cal. years in IntCal, and provides detailed 14C structure for this interval.

Dealing with Multiple Models in System Dynamics

2014 ◽  
Vol 3 (4) ◽  
pp. 17-35 ◽  
Author(s):  
Willem L. Auping ◽  
Erik Pruyt ◽  
Jan H. Kwakkel
Keyword(s):  
System Dynamics ◽  
Simulation Models ◽  
Dynamics Simulation ◽  
Multiple Models ◽  
Top Down ◽  
Bottom Up ◽  
New Approach ◽  
Behavioural Patterns ◽  
Copper Availability

This paper introduces an approach to compare simulation runs from multiple System Dynamics simulation models. Three dynamic hypotheses regarding the uncertain evolutions of long-term copper availability are introduced and used to illustrate the new approach. They correspond to three different perspectives on the copper system (global top-down, global bottom-up, and regional top-down). Although each of these models allows to generate a wealth of behavioural patterns, the focus in this paper is on the differences in trajectories caused by different models for identical values of shared parameters and identical settings of other assumptions, not on differences in behavioural patterns caused by each of the models. Hence, differences in trajectories between the three models are identified, quantified, and classified based on a quantified measure of difference. For these models, small differences between the trajectories are only found in stable runs, while the alternative perspectives are largely responsible for medium to large differences. Hence, it is concluded that multiple dynamic hypotheses may have to be modelled when dealing with uncertain issues.

Characterization of Human Sperm Protamine Proteoforms through a Combination of Top-Down and Bottom-Up Mass Spectrometry Approaches

2019 ◽  
Vol 19 (1) ◽  
pp. 221-237 ◽  
Author(s):  
Ada Soler-Ventura ◽  
Marina Gay ◽  
Meritxell Jodar ◽  
Mar Vilanova ◽  
Judit Castillo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Human Sperm ◽  
Top Down ◽  
Bottom Up

Key factors affecting long-term penetration of global onshore wind energy integrating top-down and bottom-up approaches

2016 ◽  
Vol 85 ◽  
pp. 19-30 ◽  
Author(s):  
Hancheng Dai ◽  
Diego Silva Herran ◽  
Shinichiro Fujimori ◽  
Toshihiko Masui
Keyword(s):  
Wind Energy ◽  
Key Factors ◽  
Top Down ◽  
Bottom Up ◽  
Onshore Wind ◽  
Factors Affecting

e-Den goes down under

2017 ◽  
Vol 8 (1) ◽  
pp. 34-35
Author(s):  
Paul Brunton
Keyword(s):  
Undergraduate Education ◽  
Dental Education ◽  
Daily Basis ◽  
Dental School ◽  
Top Down ◽  
Self Directed Learning ◽  
Bottom Up ◽  
Directed Learning ◽  
The Way

Change is a constant in our profession, and we are familiar with this on a daily basis, as we constantly change how we practise. But consider how the way we learn and the very structure of our profession has changed in recent years. If I think back, I attended a traditional dental school and had, in my view, an excellent undergraduate education. Compare that top-down approach to the approach today, with its self-directed learning and student-led clinics – to give a couple of examples of a bottom-up model of providing effective dental education. The net result of this, in my view, is that today’s graduates are a little different in many respects, both when they graduate and in their long-term career ambitions.

Style-Dependency of Melodic Expectation

2015 ◽  
Vol 33 (1) ◽  
pp. 110-128 ◽  
Author(s):  
Zuzana Cenkerová ◽  
Richard Parncutt
Keyword(s):  
Learning Process ◽  
Auditory Scene Analysis ◽  
Scene Analysis ◽  
Top Down ◽  
Bottom Up ◽  
Gestalt Principles ◽  
Auditory Scene ◽  
Similar Organization ◽  
Melodic Expectation

In theories of auditory scene analysis and melodic implication/realization, melodic expectation results from an interaction between top-down processes (assumed to be learned and schema-based) and bottom-up processes (assumed innate, based on Gestalt principles). If principles of melodic expectation are partly acquired, it should be possible to manipulate them – to condition listeners' expectations. In this study, the resistance of three bottom-up expectation principles to learning was tested experimentally. In Experiment 1, expectations for stepwise motion (pitch proximity) were manipulated by conditioning listeners to large melodic leaps; preference for small intervals was reduced after a brief exposure. In Experiment 2, expectations for leaps to rise and steps to fall (step declination) were manipulated by exposing listeners to melodies comprising rising steps and falling leaps; this reduced preferences for descending seconds and thirds. Experiment 3 did not find and hence failed to alter the expectation for small intervals to be followed by an interval in the same direction (step inertia). The results support the theory that bottom-up principles of melodic perception are partly learned from exposure to pitch patterns in music. The long-term learning process could be reinforced by exposure to speech based on similar organization principles.

Sign in / Sign up

Export Citation Format

Share Document