scholarly journals Modeling Spatial Innovation Diffusion from Radiocarbon Dates and Regression Residuals: The Case of Early Old World Pottery

Radiocarbon ◽  
2014 ◽  
Vol 56 (2) ◽  
pp. 723-732 ◽  
Author(s):  
Fabio Silva ◽  
James Steele ◽  
Kevin Gibbs ◽  
Peter Jordan
Keyword(s):  
Innovation Diffusion ◽  
Large Scale ◽  
Explanatory Power ◽  
Lower Latitude ◽  
Mean Annual Temperature ◽  
Radiocarbon Dates ◽  
Old World ◽  
Spatiotemporal Trends ◽  
Regression Residuals ◽  
Early Pottery

This article introduces a method of exploratory analysis of the geographical factors influencing large-scale innovation diffusion, and illustrates its application to the case of early pottery dispersal in the Old World. Regression techniques are used to identify broad-scale spatiotemporal trends in the innovation's first occurrence, and regression residuals are then analyzed to identify geographical variation (climate, biomes) that may have influenced local rates of diffusion. The boundaries between the modeled diffusion zones segregate the western half of the map into a Eurasian hunter-gatherer pottery-using zone affiliated by cultural descent to the Siberian center of innovation, and a lower-latitude farming and pastoralist zone affiliated by cultural descent to the north African center of innovation. However, the correlation coefficients suggest that this baseline model has limited explanatory power, with geographical patterning in the residuals indicating that habitat also greatly affected rates of spread of the new technology. Earlier-than-predicted ages for early pottery tend to occur in locations with mean annual temperature in the range approximately 0–15°. This favorable temperature range typically includes Mediterranean, grassland, and temperate forest biome types, but of these, the Mediterranean and the temperate deciduous forest biomes are the only ones on which regression residuals indicate earlier-than-predicted first observed pottery dates.

scholarly journals Modeling Spatial Innovation Diffusion from Radiocarbon Dates and Regression Residuals: The Case of Early Old World Pottery

Radiocarbon ◽  
2014 ◽  
Vol 56 (02) ◽  
pp. 723-732 ◽  
Author(s):  
Fabio Silva ◽  
James Steele ◽  
Kevin Gibbs ◽  
Peter Jordan
Keyword(s):  
Innovation Diffusion ◽  
Large Scale ◽  
Explanatory Power ◽  
Lower Latitude ◽  
Mean Annual Temperature ◽  
Radiocarbon Dates ◽  
Old World ◽  
Spatiotemporal Trends ◽  
Regression Residuals ◽  
Early Pottery

This article introduces a method of exploratory analysis of the geographical factors influencing large-scale innovation diffusion, and illustrates its application to the case of early pottery dispersal in the Old World. Regression techniques are used to identify broad-scale spatiotemporal trends in the innovation's first occurrence, and regression residuals are then analyzed to identify geographical variation (climate, biomes) that may have influenced local rates of diffusion. The boundaries between the modeled diffusion zones segregate the western half of the map into a Eurasian hunter-gatherer pottery-using zone affiliated by cultural descent to the Siberian center of innovation, and a lower-latitude farming and pastoralist zone affiliated by cultural descent to the north African center of innovation. However, the correlation coefficients suggest that this baseline model has limited explanatory power, with geographical patterning in the residuals indicating that habitat also greatly affected rates of spread of the new technology. Earlier-than-predicted ages for early pottery tend to occur in locations with mean annual temperature in the range approximately 0–15°. This favorable temperature range typically includes Mediterranean, grassland, and temperate forest biome types, but of these, the Mediterranean and the temperate deciduous forest biomes are the only ones on which regression residuals indicate earlier-than-predicted first observed pottery dates.

scholarly journals MAT drives the variation in maximum potential species richness and frost organizes the residual variation

2019 ◽  
Author(s):  
Ricardo A. Segovia
Keyword(s):  
Species Richness ◽  
Upper Bound ◽  
Large Scale ◽  
Explanatory Power ◽  
Mean Annual Temperature ◽  
Natural Logarithm ◽  
Residual Variation ◽  
Limited Support ◽  
Main Driver ◽  
The Relationship

AbstractThe kinetic hypothesis of biodiversity proposes that Mean Annual Temperature (MAT) is the main driver of variation in species richness, given its exponential effect on rates of energy flux and thus, potentially, on rates of biological interaction and diversification. However, limited support for this hypothesis has been found to date. We tested the fit of this model on the variation of tree species richness across the Americas. We found that the kinetic hypothesis accurately predicts the upper bound of the relationship between the inverse of temperature (1,000/kK) and the natural logarithm of species richness. In addition, we found that the number of frost days organizes a substantial portion of the residual variation. Historically, attempts to explain large-scale variation of species richness has focused on gradients of independent variables, but explanatory power has been limited. More than a gradient, the fit of the upper bound of the exponential Boltzmann temperature model of variation of observed species richness can be seen as an upper limit on the species richness per unit of MAT. Likewise, the distribution of the residuals of the upper bound model in function of the number of days with freezing temperatures, shows the importance of environmental thresholds, rather than gradients driving species richness variation.

scholarly journals Relationship between large-scale ionospheric field-aligned currents and electron/ion precipitations: DMSP observations

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Chao Xiong ◽  
Claudia Stolle ◽  
Patrick Alken ◽  
Jan Rauberg
Keyword(s):  
Time Distribution ◽  
Large Scale ◽  
Particle Flux ◽  
Particle Energy ◽  
Lower Latitude ◽  
Particle Precipitation ◽  
Data Set ◽  
The Mean ◽  
Two Parameters ◽  
Meteorological Satellite

Abstract In this study, we have derived field-aligned currents (FACs) from magnetometers onboard the Defense Meteorological Satellite Project (DMSP) satellites. The magnetic latitude versus local time distribution of FACs from DMSP shows comparable dependences with previous findings on the intensity and orientation of interplanetary magnetic field (IMF) By and Bz components, which confirms the reliability of DMSP FAC data set. With simultaneous measurements of precipitating particles from DMSP, we further investigate the relation between large-scale FACs and precipitating particles. Our result shows that precipitation electron and ion fluxes both increase in magnitude and extend to lower latitude for enhanced southward IMF Bz, which is similar to the behavior of FACs. Under weak northward and southward Bz conditions, the locations of the R2 current maxima, at both dusk and dawn sides and in both hemispheres, are found to be close to the maxima of the particle energy fluxes; while for the same IMF conditions, R1 currents are displaced further to the respective particle flux peaks. Largest displacement (about 3.5°) is found between the downward R1 current and ion flux peak at the dawn side. Our results suggest that there exists systematic differences in locations of electron/ion precipitation and large-scale upward/downward FACs. As outlined by the statistical mean of these two parameters, the FAC peaks enclose the particle energy flux peaks in an auroral band at both dusk and dawn sides. Our comparisons also found that particle precipitation at dawn and dusk and in both hemispheres maximizes near the mean R2 current peaks. The particle precipitation flux maxima closer to the R1 current peaks are lower in magnitude. This is opposite to the known feature that R1 currents are on average stronger than R2 currents.

Tracking innovation diffusion: AI analysis of large-scale patent data towards an agenda for further research

2021 ◽  
Vol 165 ◽  
pp. 120524
Author(s):  
Ashkan Fredström ◽  
Joakim Wincent ◽  
David Sjödin ◽  
Pejvak Oghazi ◽  
Vinit Parida
Keyword(s):  
Innovation Diffusion ◽  
Large Scale ◽  
Patent Data

scholarly journals Environmental and taxonomic controls of carbon and oxygen stable isotope composition in <i>Sphagnum</i> across broad climatic and geographic ranges

2018 ◽  
Vol 15 (16) ◽  
pp. 5189-5202 ◽  
Author(s):  
Gustaf Granath ◽  
Håkan Rydin ◽  
Jennifer L. Baltzer ◽  
Fia Bengtsson ◽  
Nicholas Boncek ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Isotope Composition ◽  
Explanatory Power ◽  
Isotopic Signature ◽  
Co2 Uptake ◽  
Δ13c Values ◽  
Site Variation ◽  
Species Specific

Abstract. Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO2 uptake from the atmosphere. As the isotopic composition of carbon (12,13C) and oxygen (16,18O) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is species-specific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue δ18O tracks the δ18O isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia using two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in δ13C values between species. For S. magellanicum δ13C decreased with increasing height above the water table (HWT, R2=17 %) and was positively correlated to productivity (R2=7 %). Together these two variables explained 46 % of the between-site variation in δ13C values. For S. fuscum, productivity was the only significant predictor of δ13C but had low explanatory power (total R2=6 %). For δ18O values, approximately 90 % of the variation was found between sites. Globally modelled annual δ18O values in precipitation explained 69 % of the between-site variation in tissue δ18O. S. magellanicum showed lower δ18O enrichment than S. fuscum (−0.83 ‰ lower). Elevation and climatic variables were weak predictors of tissue δ18O values after controlling for δ18O values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue δ18O values from modelled annual δ18O values in precipitation, and (b) the possibility of relating tissue δ13C values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.

scholarly journals Upside-down fluxes Down Under: CO<sub>2</sub> net sink in winter and net source in summer in a temperate evergreen broadleaf forest

2018 ◽  
Vol 15 (12) ◽  
pp. 3703-3716 ◽  
Author(s):  
Alexandre A. Renchon ◽  
Anne Griebel ◽  
Daniel Metzen ◽  
Christopher A. Williams ◽  
Belinda Medlyn ◽  
...  
Keyword(s):  
Large Scale ◽  
Vegetation Index ◽  
Ecosystem Respiration ◽  
Vapour Pressure Deficit ◽  
Summer Rainfall ◽  
Mean Annual Precipitation ◽  
Surface Conductance ◽  
Mean Annual Temperature ◽  
Eddy Covariance Method ◽  
Area Index

Abstract. Predicting the seasonal dynamics of ecosystem carbon fluxes is challenging in broadleaved evergreen forests because of their moderate climates and subtle changes in canopy phenology. We assessed the climatic and biotic drivers of the seasonality of net ecosystem–atmosphere CO2 exchange (NEE) of a eucalyptus-dominated forest near Sydney, Australia, using the eddy covariance method. The climate is characterised by a mean annual precipitation of 800 mm and a mean annual temperature of 18 ∘C, hot summers and mild winters, with highly variable precipitation. In the 4-year study, the ecosystem was a sink each year (−225 g C m−2 yr−1 on average, with a standard deviation of 108 g C m−2 yr−1); inter-annual variations were not related to meteorological conditions. Daily net C uptake was always detected during the cooler, drier winter months (June through August), while net C loss occurred during the warmer, wetter summer months (December through February). Gross primary productivity (GPP) seasonality was low, despite longer days with higher light intensity in summer, because vapour pressure deficit (D) and air temperature (Ta) restricted surface conductance during summer while winter temperatures were still high enough to support photosynthesis. Maximum GPP during ideal environmental conditions was significantly correlated with remotely sensed enhanced vegetation index (EVI; r2 = 0.46) and with canopy leaf area index (LAI; r2 = 0.29), which increased rapidly after mid-summer rainfall events. Ecosystem respiration (ER) was highest during summer in wet soils and lowest during winter months. ER had larger seasonal amplitude compared to GPP, and therefore drove the seasonal variation of NEE. Because summer carbon uptake may become increasingly limited by atmospheric demand and high temperature, and because ecosystem respiration could be enhanced by rising temperatures, our results suggest the potential for large-scale seasonal shifts in NEE in sclerophyll vegetation under climate change.

The Late Wisconsinan Savanna Terrace in Tributaries to the Upper Mississippi River

1983 ◽  
Vol 20 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Mark A. Flock
Keyword(s):  
Mississippi River ◽  
Large Scale ◽  
Lake Superior ◽  
Mississippi Valley ◽  
Red Clay ◽  
Radiocarbon Dates ◽  
Jackson County ◽  
Late Wisconsinan ◽  
Different Sources ◽  
Lacustrine Deposit

The Savanna Terrace, composed of alternating red and gray clayey sediments of late Wisconsinan age, can be found in five states along the upper Mississippi valley from Pepin County, Wisconsin, to Jackson County, Illinois. The terrace is the highest glaciofluvial-lacustrine deposit without a loess cover in the upper Mississippi valley. Chemical, physical, and mineralogical data show that two different sources provided sediment. The red clay is believed to have come from Lake Superior sources, while the gray clay is believed to have come from sources farther west. Large-scale flood events from glacial Lakes Agassiz, Grantsburg, and Superior were probably the main contributors of the sediments. The red clay in the terrace is similar in composition to red glaciolacustrine sediment found in eastern and northern Wisconsin. It also is mineralogically similar to the Hinckley Sandstone and the Fond du Lac Formation, which occur under and around Lake Superior. Radiocarbon dates obtained from the lower Illinois valley indicate that the terrace sediments were deposited sometime between about 13,100 and 9500 yr ago. Soils developed on the terrace are variable in their physical, chemical, and mineralogical properties, which reflect the composition of the clayey sediments.

Inca Imperial Strategies and Installations in Central Bolivia

2018 ◽  
Author(s):  
János Gyarmati ◽  
Carola Condarco
Keyword(s):  
Fifteenth Century ◽  
Large Scale ◽  
Raw Material ◽  
Mountain Regions ◽  
Archaeological Evidence ◽  
Radiocarbon Dates ◽  
Inca Empire ◽  
Agricultural Potential ◽  
Scale Population ◽  
The Creation

The local ethnohistoric sources and the archaeological evidence, as well as the radiocarbon dates, indicate that the Inca Empire conquered the mighty polities of Central Bolivia around the mid-fifteenth century, and then created a well-structured imperial infrastructure. The rationale behind the creation of this infrastructure can be sought in the region’s agricultural potential and raw material deposits. In order to fully exploit these resources, the Inca performed a large-scale population resettlement, principally of groups from the altiplano and the mountain regions to the eastern valleys. The goods produced in these agricultural and craft centers ensured the defense of the empire’s eastern frontiers, and contributed to the provisioning of its heartland.

An Innovation Adoption Study of Online E-Payment in Chinese Companies

2008 ◽  
pp. 1236-1254
Author(s):  
Qile He ◽  
Yanqing Duan ◽  
Zetian Fu ◽  
Daoliang Li
Keyword(s):  
Innovation Diffusion ◽  
Diffusion Theory ◽  
Explanatory Power ◽  
Relational Model ◽  
It Adoption ◽  
Adoption Study ◽  
Innovation Diffusion Theory ◽  
Chinese Companies ◽  
Innovation Attributes ◽  
It Innovations

Adoption of IT innovations is attracting increasing attention. Researchers are particularly interested in factors that affect the adoption of IS and IT innovations. Innovation diffusion theory is used frequently to evaluate the effect of perceived innovation attributes and the adoption of innovations. Nevertheless, explanatory power of perceived innovation attributes varies across different innovations. Given the importance of online e-payment to the further development of e-commerce and its importance as a payment innovation, this research examines the adoption of online e-payment by business enterprises using Rogers’ relational model of perceived innovation attributes and rate of adoption. The findings indicate that only perceived compatibility has significant influence on online e-payment adoption of Chinese companies. It is hoped that this research can help other researchers with related statistical procedures and analytical steps in their study of IS/IT adoption using innovation diffusion theory.

scholarly journals Testing Seven Hypotheses to Determine What Explains the Current Planthopper (Fulgoridae) Geographical and Species Richness Patterns in China

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 892
Author(s):  
Zheng-Xue Zhao ◽  
Lin Yang ◽  
Jian-Kun Long ◽  
Zhi-Min Chang ◽  
Zheng-Xiang Zhou ◽  
...  
Keyword(s):  
Species Richness ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Model Averaging ◽  
Ordinary Least Squares ◽  
Environmental Variable ◽  
Vital Role ◽  
Mean Annual Temperature ◽  
Spatial Error ◽  
Richness Patterns

Although many hypotheses have been proposed to understand the mechanisms underlying large-scale richness patterns, the environmental determinants are still poorly understood, particularly in insects. Here, we tested the relative contributions of seven hypotheses previously proposed to explain planthopper richness patterns in China. The richness patterns were visualized at a 1° × 1° grid size, using 14,722 distribution records for 1335 planthoppers. We used ordinary least squares and spatial error simultaneous autoregressive models to examine the relationships between richness and single environmental variables and employed model averaging to assess the environmental variable relative roles. Species richness was unevenly distributed, with high species numbers occurring in the central and southern mountainous areas. The mean annual temperature change since the Last Glacial Maximum was the most important factor for richness patterns, followed by mean annual temperature and net primary productivity. Therefore, historical climate stability, ambient energy, and productivity hypotheses were supported strongly, but orogenic processes and geological isolation may also play a vital role.

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