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1.
A major theme of current archaeological research in the Middle Atlantic region of Eastern North America is the recognition of cultural variability across space and through time. The most significant culture change experienced during the entire time frame of regional prehistory occurred ca. 5000 B.P., when there were major changes in regional environments. Before 5000 B.P., adaptations were characterized by small groups of mobile hunters and gatherers. After 5000 B.P., there were continued growth in regional populations and increases in sedentism, intensive use of a limited range of food resources, social group size, and social complexity.  相似文献   
2.
Great Basin archaeologists spent the 1970s and most of the 1980s tearing down the Desert Culture hypothesis without presenting compelling means for dealing with the empirical variability that made it untenable. Recent research seeks to understand this variability by examining the effect of key variables in extreme environmental contexts, especially in wetlands and at high altitudes, and by developing and refining models of optimality that anticipate variability as the local expression of general evolutionary ecological principles. Research on intraregional and ethnic variability has lagged behind—the former because it is said to be costly, the latter because it is problematical in theory.  相似文献   
3.
Climate-driven water variability is a natural phenomenon that is observed across river basins, but one that is predicted to increase due to climate change. Environmental change of this kind may aggravate political tensions, especially in regions which are not equipped with an appropriate institutional apparatus. Increased variability is also likely to challenge regions with existing institutional capacity. We argue that our best attempts to assess the ability of states to deal with variability in the future rest with considering how agreements have fared in the past. In this paper, we explore treaty effectiveness, or treaty resilience, by investigating whether particular water allocation and institutional mechanisms help mitigate inter-country tensions over shared water. We use water-related events from the Basins at Risk events database as a dependent variable to test particular hypotheses regarding the impact of treaty design on conflict and cooperation over time. A broad set of climatic, geographic, political, and economic variables are used as controls. The analysis is conducted for the years 1948–2001 using the country dyad as the level of observation. Findings pertaining to our primary explanatory variables suggest that country dyads governed by treaties with water allocation mechanisms exhibiting both flexibility and specificity evince more cooperative behavior. Country dyads governed by treaties with a larger sum of institutional mechanisms likewise evince a higher level of cooperation, although certain institutional mechanisms appear to be more important than others.  相似文献   
4.
The size, body conformation and skull shape of Roman dogs from the ‘Vila de Madrid necropolis’ site, where 1480 dog remains were recovered, are described in this paper to provide evidence of the morphometric variability of Roman dogs in Hispania Tarraconensis. The individualized and detailed morphometric analysis of 10 individuals shows that the proliferation and explosion of the morphological variability already documented in different regions of the Roman Empire (Italia, Gallia, Britannia, Pannonia) are also noted here. The presence of very different individuals in terms of their shape and size, similar to the differences that can at present be noted between Pekingese and Doberman dogs, has been documented at the site. The reasons for the appearance of this morphological variability within those territories that were part of the Roman Empire are also discussed. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
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6.
In this paper I evaluate the effects of wave and tidal erosion on element‐specific measures of phenotypic variability. Previous research has found a high correlation between skeletal weight, shape, and density and the transport potential of an element exposed to hydrodynamic forces. However, no previous studies have attempted to address the issue of within‐element sorting based on selective removal of only the smallest members of a given element class. I evaluate this hypothesis using a human skeletal sample from Bird Island (8DI52) located in Dixie County, Florida. This sample comprises two components, an eroded sample that was exposed during severe storm and tidal activity, and an uneroded sample excavated from primary context. The measurement‐specific means for the subcomponents were compared using Student's t and Wilcoxon tests and variability differences were evaluated based on standard deviations, coefficients of variation, and maximum/minimum indices. The data included maxillary and mandibular tooth dimensions and postcranial metrics. No evidence for selective winnowing based on within‐element size was found in this data set. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
7.
Journal of World Prehistory - This paper presents a short review of the data and new approaches to Middle Paleolithic chronology and variability in the Caucasus. A climatostratigraphic scheme of...  相似文献   
8.
Freeze‐thaw cycles are most common at the beginning or near the end of the winter season. These cycles have various effects on the ecosystems of Eastern Canada, affecting both biotic and abiotic components of temperate cold environments. Using air temperature minima and maxima from four meteorological stations close to Québec City, we determined the frequency of daily freeze‐thaw cycles for the last 30 years. The results show no significant increase in the number of freeze‐thaw cycles despite a small increase in air temperature. Polynomial curves describing the relationship between mean air temperatures and the number of freeze‐thaw cycles were calculated. Based on these equations and anticipating a climate change scenario, we projected future freeze‐thaw cycles. Assuming a 5 °C increase in mean air temperatures by 2100, we estimated that the number of days with a freeze‐thaw cycle could increase by approximately 20 days per winter. The increase in the number of such cycles will be concentrated during the coldest months of the winter (January and February).  相似文献   
9.
This study assessed the influence of the Inter-Tropical Discontinuity (ITD) on inter-annual rainfall characteristics in Nigeria between 1970 and 2000. This involved determining the strength and direction of the relationships between the total annual rainfalls in the extreme southern and northern parts of the country and the total annual rainfalls during the period of the Little Dry Season in southwestern Nigeria, and the surface locations of the ITD over Nigeria and some other factors that may impact ITD characteristics (such as the pressure differences between Azores, Libyan and St. Helena anticyclones and the sea surface temperature of the Gulf of Guinea). Results indicate that although the surface location of the ITD significantly accounts for rainfall inter-annual variability in Nigeria, it does so in the northern part of the country only. Pressure differences between the various anticyclones were observed to be another significant factor influencing inter-annual rainfall variability in the north. However, the influence of the sea surface temperature of the Gulf of Guinea on the rainfall characteristics in the northern region is ill-defined. It was also noted that the only factor influencing inter-annual variability in the Little Dry Season rainfall in the southwest and the total annual rainfalls in the south is the sea surface temperature of the Gulf of Guinea. The results obtained indicate that the total annual rainfalls in the north have significant positive relationships with the surface location of the ITD but significant negative relationships with the pressure differences between the Azores, Libyan and St. Helena anticyclones. The Little Dry Season rainfalls and total annual rainfalls in the south have significant positive relationships with the sea surface temperature of the Gulf of Guinea.  相似文献   
10.
The stable carbon and nitrogen isotope ratios of collagen of seven bones from each of three rabbits raised on a monotonous diet, and of two bones from each of eight female and seven male mink raised on another monotonous diet, were determined. The ranges of δ13C values and δ15N values were 0·5‰ and 0·6‰ for the rabbit bones and 1·0‰ and 1·4‰ for the mink bones. Uncertainties in the δ13C and δ15N values for prehistoric human diets estimated from the isotopic composition of collagen from the small numbers of bones which are typically available for analysis, and thus likely to be of the order of ±1‰.  相似文献   
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