scholarly journals A Method for Palaeoclimatic Reconstruction in Palynology Based on Multivariate Time-Series Analysis

2007 ◽  
Vol 39 (2) ◽  
pp. 115-125 ◽  
Author(s):  
Joël Guiot
Keyword(s):  
Human Activity ◽  
Multivariate Time Series ◽  
Analytical Techniques ◽  
Climate Data ◽  
Climatic Forcing ◽  
Study Region ◽  
Third Stage ◽  
Regression Techniques ◽  
Two Stages ◽  
Standard Techniques

ABSTRACT A method based on multiple regression, canonical correlation analysis and the Kalman filter is developed with a view to producing a reliable reconstruction of climate from pollen spectra. The study region is the southern France, where traditional analytical techniques are unsatisfactory due to the heavy influence of human activity and the existence of a complex climate. The first stage of the proposed method is the same as the standard techniques in which a spatial network of 36 sites with recent pollen and climate data were analyzed by regression techniques. But since the recent data are frequently subjected to disturbance by such factors as human activity or the particularities of the local vegetations, a second, independent analytical stage was added, in which pairs of fossil sites were compared using ancient data exclusively. In this way a model of the climatic forcing can be obtained, with the above-mentioned factors left out of account. The reconstructions obtained from the first two stages were then compared in the third stage of the method, and the result is a corrected reconstruction, from which it appears that at 14 000 BP annual temperature was 9oC cooler than present, with a 4°C increase between 13 500 and 11 500 BP followed by a 2oC cooling at 10 500 BP. The Holocene temperature maximum occurred between 8000 and 6000 BP. when the temperature was 1°C warmer than present.

The Origins of the Village Revisited: From Nuclear to Extended Households

2002 ◽  
Vol 67 (3) ◽  
pp. 417-433 ◽  
Author(s):  
Kent V. Flannery
Keyword(s):  
Nuclear Family ◽  
Extended Family ◽  
Near East ◽  
Shared Storage ◽  
Nuclear Families ◽  
Second Stage ◽  
Third Stage ◽  
Two Stages ◽  
Extended Households ◽  
The Village

In Mesoamerica and the Near East, the emergence of the village seems to have involved two stages. In the first stage, individuals were distributed through a series of small circular-to-oval structures, accompanied by communal or “shared” storage features. In the second stage, nuclear families occupied substantial rectangular houses with private storage rooms. Over the last 30 years a wealth of data from the Near East, Egypt, the Trans-Caucasus, India, Africa, and the Southwest U.S. have enriched our understanding of this phenomenon. And in Mesoamerica and the Near East, evidence suggests that nuclear family households eventually gave way to a third stage, one featuring extended family households whose greater labor force made possible extensive multifaceted economies.

Order-disorder phenomena in α -brass - III. Influence of plastic deformation

1960 ◽  
Vol 257 (1290) ◽  
pp. 363-385 ◽  
Keyword(s):  
Plastic Deformation ◽  
Cold Work ◽  
Stored Energy ◽  
High Concentration ◽  
Complex Behaviour ◽  
Second Stage ◽  
Third Stage ◽  
Anneal Hardening ◽  
Two Stages ◽  
Degree Of Order

The evolution of stored energy during heating for specimens of deformed α-brass is quite different from that previously observed for pure metals; the stored energy is much larger and at least three stages of evolution exist. These have been studied for deformation in torsion and tension and the results correlated with measurements of electrical resistivity, density and hardness. The large release of energy in the first two stages is attributed mainly to the return of order destroyed by plastic deformation; the degree of disorder after heavy cold work is much greater than after quenching (part II). However, slight deformation (10% tension) increases the degree of order slightly. The first stage of energy release, below 120 °C, is probably due to rapid reordering assisted by vacancies created during deformation. The second stage represents the bulk of the reordering and some recovery involving rearrangement and annihilation of dislocations. The deformed specimens are probably strain-aged and thus recovery is accompanied by the dispersal of atmospheres of zinc which increases resistivity and decreases density, to some extent counteracting the effects of recovery. The balance of these three processes in stage 2 causes complex behaviour, the magnitude and even the sign of some changes in properties varies with the deformation. Reordering is complete before the beginning of the third stage of further recovery and recrystallization, in which dispersal of atmospheres is again important. Comparison of measurements of energy, resistivity and density suggests that the high concentration of stacking faults contributes to the resistivity. Anneal hardening is observed for the higher deformations and the maximum hardness coincides with the maximum degree of order.

scholarly journals Estimating time delays for constructing dynamical networks

2014 ◽  
Vol 21 (5) ◽  
pp. 929-937 ◽  
Author(s):  
E. A. Martin ◽  
J. Davidsen
Keyword(s):  
Random Walk ◽  
Time Delays ◽  
Large Time ◽  
Multivariate Time Series ◽  
Time Lag ◽  
Time Lags ◽  
Climate Data ◽  
Dynamical Networks ◽  
Frequency Space ◽  
Cross Correlations

Abstract. Dynamical networks – networks inferred from multivariate time series – have been widely applied to climate data and beyond, resulting in new insights into the underlying dynamics. However, these inferred networks can suffer from biases that need to be accounted for to properly interpret the results. Here, we report on a previously unrecognized bias in the estimate of time delays between nodes in dynamical networks inferred from cross-correlations, a method often used. This bias results in the maximum correlation occurring disproportionately often at large time lags. This is of particular concern in dynamical networks where the large number of possible links necessitates finding the correct time lag in an automated way. We show that this bias can arise due to the similarity of the estimator to a random walk, and are able to map them to each other explicitly for some cases. For the random walk there is an analytical solution for the bias that is closely related to the famous Lévy arcsine distribution, which provides an upper bound in many other cases. Finally, we show that estimating the cross-correlation in frequency space effectively eliminates this bias. Reanalysing large lag links (from a climate network) with this method results in a distribution peaked near zero instead, as well as additional peaks at the originally assigned lag. Links that are reassigned smaller time lags tend to have a smaller distance between them, which indicates that the new time delays are physically reasonable.

Signs of polichnous deformations in microstructures of carbonate rocks of the Katav-Yuryuzan zone of transpression (Southern Urals)

2020 ◽  
pp. 13-21
Author(s):  
A. V. Tevelev ◽  
A. A. Borisenko ◽  
M. I. Erokhina ◽  
S. S. Popov ◽  
I. A. Kosheleva ◽  
...  
Keyword(s):  
Simple Shear ◽  
Carbonate Rocks ◽  
Pure Shear ◽  
Southern Urals ◽  
Second Stage ◽  
The Third ◽  
The North ◽  
Third Stage ◽  
Three Stages ◽  
Two Stages

The Katav-Ivanovsk transpression zone experienced at least two stages of tectonic deformations, and the sequence of deformations was approximately the same throughout the entire zone — from the Bakal-Satka fault in the south to the Suleimsky fault in the north. Three stages of the formation of parageneses were identified. The parageneses of the first and the second stages were formed in a pure shear environment, and the paragenesis of the third stage — in a simple shear environment. There are stylolites (S1) parallel to bedding, and mineral veins (V1) in the paragenesis of the first stage. Paragenesis of the second stage combines stylolites (S2), mineral veins (V2) and intergranular cleavage (S2). In paragenesis of the third stage were distinguished schistosity (S3), milonites (S3), cataclasites, mica packets (SC-textures), and the rotation structures of porphyroblasts.

scholarly journals Bomb Radiocarbon in Tree Rings from Northern New South Wales, Australia: Implications for Dendrochronology, Atmospheric Transport, and Air-Sea Exchange of CO2

Radiocarbon ◽  
2003 ◽  
Vol 45 (3) ◽  
pp. 431-447 ◽  
Author(s):  
Quan Hua ◽  
Mike Barbetti ◽  
Ugo Zoppi ◽  
David M Chapman ◽  
Bruce Thomson
Keyword(s):  
Pinus Radiata ◽  
Atmospheric Transport ◽  
New South ◽  
New South Wales ◽  
Ring Width ◽  
Study Region ◽  
False Rings ◽  
South Wales ◽  
Bomb Radiocarbon ◽  
Standard Techniques

We have analyzed by radiocarbon 27 consecutive single rings, starting from AD 1952, of a preliminarily cross-dated section (DFR 021) of Pinus radiata, which grew in Armidale, northern New South Wales, Australia. The bomb 14C results suggested the possibility of 2 false rings, and, consequently, 2 misidentified rings in the preliminary count for this section. This possibility was supported by a better ring-width correlation between the revised DFR 021 count and other Pinus radiata chronologies in the study region. This indicated that bomb 14C is a useful tool to complement the standard techniques of dendrochronology in tree species where annual rings are not always clearly defined.

A THREE-STEP COMBINED GENETIC PROGRAMMING AND NEURAL NETWORKS METHOD OF FORECASTING THE S&P/CASE-SHILLER HOME PRICE INDEX

2013 ◽  
Vol 12 (01) ◽  
pp. 1350001 ◽  
Author(s):  
MAK KABOUDAN ◽  
MARK CONOVER
Keyword(s):  
Neural Networks ◽  
Genetic Programming ◽  
San Francisco ◽  
Price Index ◽  
Combined Method ◽  
Second Stage ◽  
Third Stage ◽  
Multi Agent ◽  
Stage Process ◽  
Two Stages

Forecasts of the San Diego and San Francisco S&P/Case-Shiller Home Price Indices through December 2012 are obtained using a multi-agent system that utilizes January, 2002–June, 2011 data. Agents employ genetic programming (GP) and neural networks (NN) in a three-stage process to produce fits and forecasts. First, GP and NN compete to provide independent predictions. In the second stage, they cooperate by fitting the first-stage competitor's residuals. Outputs from the first two stages then become inputs to produce two final GP and NN outputs. The NN output from the third stage using the combined method produces improved forecasts over the 3-stage GP method as well as those produced by either method alone. The proposed methodology serves as an example of how combining more than one estimation/forecasting technique may lead to more accurate forecasts.

A Bibliography of Soviet Studies of the Ancient Cultures of Latin America

1990 ◽  
Vol 1 (1) ◽  
pp. 5-22
Author(s):  
V. A. Bashilov ◽  
V. I. Gulyaev
Keyword(s):  
Latin America ◽  
Latin American ◽  
Latin American Studies ◽  
Historical Processes ◽  
Third Stage ◽  
Archaeological Materials ◽  
Art And Culture ◽  
History Of ◽  
Two Stages ◽  
Second Period

The study in the Union of Soviet Socialist Republics of the earliest history of native Latin Americans falls into two distinct periods. The first, associated with an interest in the ancient Mexican and Peruvian civilizations, can be divided into two stages: the 1920s to the early 1940s, when Soviet scholars first acquainted themselves with antiquities from the region and used them for historical parallels; and the late 1940s and early 1950s, when Soviet historians turned to an analysis of Latin American materials. The second period went through three stages: the first, from the early 1950s to the early 1960s, mainly was dominated by Yury Knorozov, who was engaged in deciphering the language of the Maya, and Rostislav Kinzhalov, who studied their art and culture. During the second stage, the early 1960s to the mid-1970s, more scholars and research institutions undertook studies of the early cultures of Latin America. The thematic range became wider as well, covering—besides Mesoamerica and the central Andean region—the Intermediate region and the Caribbean. The third stage, which started in the late 1970s and continues to the present day, witnesses ethnographers and archaeologists pooling their efforts in studying the region. There were several conferences in which specialists engaged in various fields of Latin American studies participated. Their contacts with foreign colleagues became wider; Soviet archaeologists and ethnologists took part in fieldwork in Latin America. The primary aims today are to introduce Soviet readers to archaeological materials from a number of cultural-historical regions (such as the southern fringes of Mesoamerica, Amazonia, the southern Andes, etc.), to detail Soviet studies of cultural complexes and historical processes in ancient America, and to compare them to the processes that took place in the Old World, with the aim of establishing shared historical “laws” and patterns.

Cytochemical and ultrastructural differences between intraspecific compatible and incompatible pollinations in Raphanus

1973 ◽  
Vol 183 (1070) ◽  
pp. 21-38 ◽  
Keyword(s):  
Pollen Tube ◽  
The Self ◽  
Self Incompatibility ◽  
Second Stage ◽  
Incompatible Pollen ◽  
Large Numbers ◽  
Third Stage ◽  
Incompatibility System ◽  
Three Stages ◽  
Two Stages

Examination of the behaviour of pollen on the style of Raphanus , following compatible and incompatible intraspecific pollinations, has revealed the self-incompatibility system in this species to be composed of at least three stages. The first, on which no information has been obtained in this study, involves the germination of the grain. The second stage concerns the ability of the pollen tube to penetrate the cuticle of the stigmatic papilla. It is possible that cutinase is deficient in incompatible pollen tubes but, in most instances, the outer layers of the stigmatic wall are penetrated. The third stage involves the interaction of substances secreted by the pollen tube with products of the stigmatic cytoplasm. The interaction is swiftly followed by the deposition, in the stigma, of a layered callosic body. This is formed immediately under the point of penetration and takes about 6 h to develop fully. Development of the pollen tube ceases as the first layers of callose are laid down. It is possible that the substances in the pollen responsible for the initiation of the second two stages are held in the tapetally synthesized tryphine, thus accounting for the sporophytic control of pollen compatibility in this species. The mature stigma contains large numbers of crystalline protein bodies, but it is not known whether they play any role in the self-incompatibility system.

The “Sanctions” of the International Monetary Fund

1972 ◽  
Vol 66 (4) ◽  
pp. 737-762 ◽  
Author(s):  
Joseph Gold
Keyword(s):  
International Monetary Fund ◽  
International Monetary System ◽  
The United States ◽  
Legal Structure ◽  
Monetary System ◽  
Special Drawing ◽  
Third Stage ◽  
Special Drawing Rights ◽  
Two Stages ◽  
The International Monetary Fund

Recent events in the international monetary system culminating in the decision of the United States, announced on August 15, 1971, to suspend the convertibility of the dollar induce the international lawyer to ask once again what contribution sanctions can make to respect for international law and the effectiveness of multilateral treaties. This question has been a practical problem at two stages in the development of the International Monetary Fund. It arose first during the negotiation and drafting of the original Articles of Agreement which were adopted at the Bretton Woods Conference in July 1944. The second stage was the negotiation and drafting of the amendment of July 28, 1969, which dealt mainly with the legal structure of special drawing rights as a supplement to existing reserve assets. It is now apparent that there will be a third stage, in which a reform of the international monetary system, perhaps in some of its most fundamental aspects, will lead to a further amendment of the Fund's charter.

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