Astronomical Theory of Climatic Change: Status and Problem

1973 ◽  
Vol 3 (2) ◽  
pp. 221-236 ◽  
Author(s):  
J. Chappell
Keyword(s):  
Climatic Change ◽  
Deep Sea ◽  
Frequency Domain Analysis ◽  
Sea Levels ◽  
Orbital Perturbations ◽  
Climatic Control ◽  
Degree Of Certainty ◽  
Astronomical Theory ◽  
High Degree ◽  
Isotope Analyses

AbstractQuaternary paleotemperatures and sea level records, from both deep sea cores and dated shorelines, provide the basis for testing the Milankovitch hypothesis of climatic change. The longest and most detailed records include (1) oxygen isotope analyses of Caribbean and Atlantic deep sea cores, (2) paleoecological analyses of the same cores, and (3) radiometrically dated raised coral reefs from New Guinea and elsewhere, representing times of relatively high Quaternary sea levels. Time-domain and frequency-domain analysis of these records, shows with a high degree of certainty that Quaternary climatic changes are strongly influenced by the obliquity perturbations and precession of the Earth's orbit. The same analyses also suggest that the time scale adopted by Emiliani for deep sea cores may be more nearly correct than alternative time scales of other workers.The question of whether insolation changes arising from orbital perturbations can generate ice ages, has been disputed by climatologists. It is shown here that orbital perturbations cannot affect climate indirectly through agencies originating within the Earth, such as vulcanism, and that the primary climatic control is therefore through variation of insolation distribution, as Milankovitch suggested. The conclusion is that climatologic theory must accommodate these facts.

scholarly journals An approach using ddRADseq and machine learning for understanding speciation in Antarctic Antarctophilinidae gastropods

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juan Moles ◽  
Shahan Derkarabetian ◽  
Stefano Schiaparelli ◽  
Michael Schrödl ◽  
Jesús S. Troncoso ◽  
...  
Keyword(s):  
Machine Learning ◽  
Deep Sea ◽  
Weddell Sea ◽  
Nucleotide Polymorphisms ◽  
Sea Levels ◽  
Suitable Material ◽  
Genetic Lineages ◽  
Genome Wide ◽  
Gastropod Mollusks ◽  
Double Digestion

AbstractSampling impediments and paucity of suitable material for molecular analyses have precluded the study of speciation and radiation of deep-sea species in Antarctica. We analyzed barcodes together with genome-wide single nucleotide polymorphisms obtained from double digestion restriction site-associated DNA sequencing (ddRADseq) for species in the family Antarctophilinidae. We also reevaluated the fossil record associated with this taxon to provide further insights into the origin of the group. Novel approaches to identify distinctive genetic lineages, including unsupervised machine learning variational autoencoder plots, were used to establish species hypothesis frameworks. In this sense, three undescribed species and a complex of cryptic species were identified, suggesting allopatric speciation connected to geographic or bathymetric isolation. We further observed that the shallow waters around the Scotia Arc and on the continental shelf in the Weddell Sea present high endemism and diversity. In contrast, likely due to the glacial pressure during the Cenozoic, a deep-sea group with fewer species emerged expanding over great areas in the South-Atlantic Antarctic Ridge. Our study agrees on how diachronic paleoclimatic and current environmental factors shaped Antarctic communities both at the shallow and deep-sea levels, promoting Antarctica as the center of origin for numerous taxa such as gastropod mollusks.

A Statistical Predictive Model to Prioritize Site Selection for Stress Corrosion Cracking Direct Assessment

2006 ◽  
Author(s):  
Anthony Merle ◽  
P. F. Ehlers
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Environmental Parameters ◽  
Predictive Modelling ◽  
Corrosion Cracking ◽  
Direct Assessment ◽  
Degree Of Certainty ◽  
Regression Techniques ◽  
Selection For ◽  
High Degree

Pipeline stress-corrosion cracking (SCC) is an ongoing integrity concern for pipeline operators. A number of different strategies are currently employed to locate and mitigate SCC. Ultrasonic in-line inspection tools have proven capable of locating SCC, but reliability of these tools in gas pipelines remains in question. Rotating hydrotest programs are effectively employed by some companies but may not provide useful information as to the location of SCC along the pipeline. NACE Standard RP0204-2004 (SCC Direct Assessment Methodology) outlines factors to consider and methodologies to employ to predict where SCC is likely to occur, but even this document acknowledges that there are no well-established methods for predicting the presence of SCC with a high degree of certainty. Predictive modelling attempts to date have focused on establishing quantitative relationships between environmental factors and SCC formation and growth; these models have achieved varying degrees of success. A statistical approach to SCC predictive modelling has been developed. In contrast to previous models that attempted to determine direct correlations between environmental parameters and SCC, the new model statistically analyzed data from dig sites where SCC was and was not found. Regression techniques were used to create a multi-variable logistic regression model. The model was applied to the entire pipeline and verification digs were performed. The dig results indicated that the model was able to predict locations of SCC along the pipeline.

scholarly journals Quantum-Like Interdependence Theory Advances Autonomous Human–Machine Teams (A-HMTs)

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1227
Author(s):  
William F. Lawless
Keyword(s):  
Autonomous Systems ◽  
Quantum Decoherence ◽  
Multi Agent Systems ◽  
Scale Free ◽  
Weapon Systems ◽  
Interdependence Theory ◽  
Human Autonomy ◽  
Degree Of Certainty ◽  
Human Operators ◽  
High Degree

As humanity grapples with the concept of autonomy for human–machine teams (A-HMTs), unresolved is the necessity for the control of autonomy that instills trust. For non-autonomous systems in states with a high degree of certainty, rational approaches exist to solve, model or control stable interactions; e.g., game theory, scale-free network theory, multi-agent systems, drone swarms. As an example, guided by artificial intelligence (AI, including machine learning, ML) or by human operators, swarms of drones have made spectacular gains in applications too numerous to list (e.g., crop management; mapping, surveillance and fire-fighting systems; weapon systems). But under states of uncertainty or where conflict exists, rational models fail, exactly where interdependence theory thrives. Large, coupled physical or information systems can also experience synergism or dysergism from interdependence. Synergistically, the best human teams are not only highly interdependent, but they also exploit interdependence to reduce uncertainty, the focus of this work-in-progress and roadmap. We have long argued that interdependence is fundamental to human autonomy in teams. But for A-HMTs, no mathematics exists to build from rational theory or social science for their design nor safe or effective operation, a severe weakness. Compared to the rational and traditional social theory, we hope to advance interdependence theory first by mapping similarities between quantum theory and our prior findings; e.g., to maintain interdependence, we previously established that boundaries reduce dysergic effects to allow teams to function (akin to blocking interference to prevent quantum decoherence). Second, we extend our prior findings with case studies to predict with interdependence theory that as uncertainty increases in non-factorable situations for humans, the duality in two-sided beliefs serves debaters who explore alternatives with tradeoffs in the search for the best path going forward. Third, applied to autonomous teams, we conclude that a machine in an A-HMT must be able to express itself to its human teammates in causal language however imperfectly.

Reconciliaion of late Quaternary sea levels derived from coral terraces at Huon Peninsula with deep sea oxygen isotope records

1996 ◽  
Vol 141 (1-4) ◽  
pp. 227-236 ◽  
Author(s):  
John Chappell ◽  
Akio Omura ◽  
Tezer Esat ◽  
Malcolm McCulloch ◽  
John Pandolfi ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Deep Sea ◽  
Late Quaternary ◽  
Sea Levels

scholarly journals Agile methodology of well pad development

2020 ◽  
Vol 10 (8) ◽  
pp. 3483-3496
Author(s):  
Aleksandr Abramov
Keyword(s):  
Project Management ◽  
Net Present Value ◽  
Computational Study ◽  
Petroleum Industry ◽  
Development Projects ◽  
Agile Methodology ◽  
Modern Project ◽  
Degree Of Certainty ◽  
Unequal Number ◽  
High Degree

Abstract Placing of wells in clusters with unequal number of thereof is an emerging concept of well pad development which still requires scrutiny even from a theoretical standpoint. The concept has its potential in improving economic efficiency of one of the most capital intensive processes in upstream sector of petroleum industry—the well pad drilling. To advocate and strengthen this profitability enhancing potential, this work integrates clustering of unequal number of wells into modern project management methodologies (agile project management), which has not been done before. It is shown that such symbiosis, which is called here the adaptive well pad development (or agile methodology of well pad development), has twofold benefit consisting of (1) managing of and accounting for uncertainties of real projects and (2) further improving economic performance of development projects in comparison with standalone well pad configurations with unequal number of wells. To exemplify these advantages, detailed simulations of well pad drilling projects were performed with equal and unequal number of wells in clusters. The simulation model accounting for more than 40 parameters and individual features of wells shows that combination of unequal well clustering configurations with adaptation of well pad designs to updates in project parameters results in significant improvements to the net present value (NPV). For three drilling scenarios studied in this work, the NPV increments ranged from 8 to 36%. Additionally, it was found that groupings with unequal number of wells consistently outperform groupings with equal number of wells in uncertain conditions, and NPV improvements from 10 to 20% have been obtained. These findings enrich understanding of the vast space of clustering schemes with unequal number of wells and demonstrate how these well pad configurations can be applied to use ever-changing environment to one's advantage. On basis of this computational study, it is now valid to assert with high degree of certainty and confidence that industrial deployment of clustering with unequal number of wells in combination with proper organizational measures results in boost to the NPV of well pad development projects at the level of several to tens of percent.

scholarly journals Trace element and stable isotope analyses of deep sea fish from the Sulu sea, Philippines

2009 ◽  
Vol 14 (1) ◽  
Author(s):  
KA Asante ◽  
R Kubota ◽  
T Agusa ◽  
A Subramanian ◽  
S Tanabe ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Trace Element ◽  
Deep Sea ◽  
Stable Isotope Analyses ◽  
Sulu Sea ◽  
Sea Fish ◽  
Isotope Analyses

scholarly journals Special issue on cognitive approaches to the history of English: introduction

2017 ◽  
Vol 21 (2) ◽  
pp. 193-202 ◽  
Author(s):  
ALEXANDER BERGS ◽  
THOMAS HOFFMANN
Keyword(s):  
Early Modern ◽  
Historical Period ◽  
Historical Evidence ◽  
The Past ◽  
Linguistic Evidence ◽  
Degree Of Certainty ◽  
Third Person ◽  
History Of ◽  
State Of Affairs ◽  
High Degree

What do we know about the past? For at least some languages, we have textual (or archaeological) evidence from various periods – beyond that, there is only reconstruction. But even when we have some textual evidence, what does it tell us? The answer to this question crucially depends on the way we approach the question: we can treat texts as decontextualized, linguistic evidence, as Neogrammarian or Structuralist studies have done (see McMahon 1994: 17–32). Such an approach already allows us to discover important generalizations about the linguistic state of affairs of a particular language or historical period. Using decontextualized historical evidence, for example, we can already ascertain with a high degree of certainty that in Old English voiced and voiceless fricatives were allophones, rather than phonemes, that there was nodo-periphrasis in Middle English, and that in Early Modern English there was some variability between third-person singular present tense {-s} and {-th} – just as we know that present-day Japanese and Korean use postpositions, rather than prepositions.

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