Craniometric Variation In The Northern And Central Plains

Abstract

Cranial measurements of 13 male and 12 female samples from the Central and Northern Plains region were subjected to canonical analysis. The samples include historic or protohistoric crania that can be ascribed to the Arikara, Mandan, Pawnee, Ponca and Omaha tribes. In addition, two samples belong to the archaeologically defined St. Helena Focus. Both sexes yielded five significant canonical variates, although only four were readily interpretable. The first canonical variate is clearly a Siouan-Caddoan discriminator and reflects variation in cranial vault height. St. Helena sites associate with the Arikara on this axis, supporting previous craniometric analyses which suggest a relationship between these two groups. Subsequent canonical variates deal with more particular aspects of craniometric variation among groups, but are still interpretable in historic or evolutionary terms. The classificatory analysis shows that the Arikara sites are closely related. A major exception to this is the Sully site, which frequently misclassifies with non-Arikara groups. This suggests that the Sully crania have little collective reality; and that there may be non-Arikara components represented at the Sully Site.     

Toggle Head Harpoons of the Central Plains

Abstract

An examination of ten single piece, toggle harpoon heads from Nebraska and Iowa reveals that this implement is a diagnostic trait of the Nebraska Phase and that its place of origin probably lies with the Woodland complexes to the east and around the Great Lakes region.     

Temporal and Spatial Order in the Central Plains

Abstract

The major archeological complexes of the Central Plains can be arranged according to the Willey and Phillips system, thus recognizing not only content but time and space diemnsions.     

Antler Tine Scraper Handles in the Central Plains

Abstract

In the perspectives of archaeology, it is evident that the widespread antler-handled fleshing adz used by most historic Plains Indian tribes was preceded in the region by other types of hafted skin-working tools. These, inferentially, varied in construction and materials from area to area, but were everywhere provided with planoconvex chipped stone blades - the familiar and omnipresent end scraper of the Plains. In early historic times in the Central Plains, curved antler handles with stone blades are thought from archaeological evidence to have been used not in adz fashion but with a pushing motion, away from the operator. The relative abundance, variety in size and form, and longevity as an artifact type of the plano-convex end scraper raises various questions that invite further inquiry.     

Cytokine-Induced Inflammation in the Central Nervous System Revisited

Cytokines play an essential role as mediators of the immune response. They usually function as part of a network of interactive signals that either activate, enhance, or inhibit the ensuing reaction. An important contribution of this cytokine cascade is the induction of an inflammatory response that recruits and activates subsets of leukocytes that function as effector cells in the response to the sensitizing antigen. Proinflammatory cytokines activate endothelial cells (EC) to express adhesion molecules and induce the release of members of the chemokine family, thus focusing and directing the inflammatory response to sites of antigen recognition. However, the vasculature of the central nervous system (CNS) is highly specialized and restricts the access of components of the immune system to the CNS compartment. In this review, we address the question as to whether endothelial cells in the CNS respond differently to specific cytokines known to induce either a proinflammatory effect or a regulatory effect in systemic vascular beds.     

House Floors and Native Settlement Populations in the Central Plains

Abstract

The quantitative relationships between aboriginal abuse floor and village areas and the associated native populations have long interested archeologists and lrehistorians. With varying success, formulae for lStimating these relationships have been proposed for some groups in certain regions and at different levels of cultural complexity. The present paper undertakes o correlate Central Plains historical, ethnographical, md archeological materials on the Pawnee and Nichita in search of clues to the estimation of prehistoric population patterns in the region. It is suggested that documentary evidence points toward a atio of approximately 5 square meters per person tmong the historic peoples, who inhabited circular one-room structures with lodge populations someimes reported to reach 50 people per house. rcheological evidence indicates that the subrecangular dwellings of the prehistoric Central Plains Tradition were generally smaller, with one-or two-family habitations perhaps more common than he larger multi-family households of the post-White contact period.     

Herbicides for Establishing Switchgrass in the Central and Northern Great Plains

Weed interference limits switchgrass (Panicum virgatum L.) establishment from seed. Our objectives were to determine the effect of selected post-plant, preemergence herbicides on stand establishment and subsequent biomass yields of adapted upland switchgrass cultivars grown in three environments in the Central and Northern Great Plains. A separate experiment was conducted in eastern Nebraska to determine if there were any differences among switchgrass ecotypes for herbicide tolerance to the optimal herbicide combination. Herbicides applied immediately after planting were different concentrations of atrazine [Aatrex 4L®; 6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], quinclorac (Paramount®; 3,7-Dichloro-8-quinolinecarboxylic acid), atrazine+quinclorac, imazapic {Plateau®; 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid}, and quinclorac+imazapic. Herbicide efficacy was determined by measuring stand frequency of occurrence and biomass yield the year after establishment. The application of quinclorac plus atrazine resulted in acceptable stands and high biomass yields. Imazapic often reduced switchgrass stands in comparison to the nontreated control and is not recommended for switchgrass establishment. In the multi-state trials, the herbicide by cultivar interaction was not significant for stands or biomass yields, indicating that the effects of herbicides on switchgrass stands and biomass yields were consistent over the upland cultivars used in the trials. No differences were detected among switchgrass lowland and upland ecotypes for tolerance to atrazine and quinclorac. Quinclorac, which provides effective control of grassy weeds, and herbicides such as atrazine which provide good broadleaf weed control are an excellent herbicide combination for establishing switchgrass for biomass production in the Great Plains and the Midwest.     

Temporal And Geographic Patterning of Relative Head Height in The Central Plains And Middle Missouri Areas

Abstract

Temporal and geographic patterning of vault height evaluated as the Auricular Mean Height Index is examined in samples of crania from the Central and Northern Plains. Crania are placed into two large categories: one consisting of historic Caddoan speakers and their ancestors, the other of Mandan speakers and their ancestors. Woodland crania from the Central Plains and Middle Missouri areas are added to their respective groups for part of the analysis. Time consistently shows a strong relationship to Auricular Mean Height Index; geographical latitude is equivocal but does exhibit a relationship to the vault height index in Central Plains-Caddoan without Woodland. Auricular height decreases with the passage of time and increases as one proceeds northward. The analysis further shows that Central Plains Caddoan groups have higher vaults than Middle Missouri-Mandan crania at a given point in time and space. That cranial morphology is different in the groups supports the notion that gene pool differences are responsible. The causes of decreasing head height through time are unknown.     

中原城市群生态效率时空演变及影响因素

提高生态效率是推进生态文明建设和绿色发展的重要途径。基于2003—2016年中原城市群29个城市的面板数据,运用Super-SBM(超效率SBM模型, Super slacks-based model)模型对生态效率进行测算,并综合运用GIS技术与空间滞后模型,分析了生态效率的时空演变及空间关联特征,研究了生态效率变动的影响因素。结果表明:(1)2003—2016年,中原城市群生态效率总体上呈"阶梯状"的上升趋势,空间分布存在差异,形成了北部和南部高,中间低的空间格局。(2)中原城市群生态效率呈正向空间自相关,空间集聚趋势逐步增强,冷点区在西北部地区动态变化,东南部地区形成稳定的热点区。(3)中原城市群生态效率存在正向空间溢出效应,经济发展水平和对外开放水平产生显著正向效应,而科技水平产生显著负向效应。     

Pollination biology in a palm swamp community in the Venezuelan Central Plains

RAMIREZ, N. & BRITO, Y., 1992. Pollination biology in a palm swamp community in the Venezuelan central plains. In a palm swamp community that differs strongly from the surrounding savanna in the Venezuelan central plains, the pollination and floral biology of 33 plant species were studied during three years: 1983, 1984 and 1989. The most frequent flower colours were white, pink, yellow, and in a lesser proportion green, brown, purple and red. Floral symmetry was found in roughly equal proportion for actinomorphic and zygomorphic flowers. Most flowers were short-lived (6–12 hours); in monoecious species the female flowers were longer-lived than the male flowers. The most frequent rewards were pollen and nectar (36.4%) and pollen (30.3%). At the community level, bee- and wasp-pollination prevailed in 57.1% of plant species studies, followed by wind- (14.3%), fly- (11.4%), butterfly- (8.6%), bird- (5.7%) and beetle-pollination (2.9%). Between one and five plant species were simultaneously visited by the visitor species. The vast majority of the pollinating species displayed a high degree of load specificity: 26 pollinator species (65.0%) carried pollen from only one plant species, eight (20.0%,) carried pollen from two plant species, three (7.5%) carried pollen from three plant species and one (2.5%) carried pollen from five plant species. Visitor specificity and pollen transportation were similar amongst the visiting agents. Plant pollination-system specificity and pollen transportation were statistically significant among plant species with different pollinator types, but plant pollination system and pollen transportation were not different among floral symmetry, floral longevity, reward type, plant sexuality, breeding system and plant life form. The visitor species/plant species ratio was 1.6, and the pollinator species/ plant species ratio was 1.3. Among different guilds, birds, Coleoptera and Lepidoptera showed the highest pollinator species/plant species ratio, and wind pollination exhibited the lowest.     

Archaic Skeletal Remains from the Central Plains: Demography and Burial Practices

Abstract

Recently a number of reports on Plains Archaic skeletal material have been published which quadruple the number of burials described and analyzed in the literature. Although the total number of burials is still relatively small, it is large enough to allow research to begin in paieodemographic aspects of the central part of thePlains and the suggestion of burial patterns for these materials. By combining all Archaic burials from the Plains a demographic profile has been developed. It is compared with other Archaic populations from the eastern United States, and with a Plains population dating after A.O. 1000. The results of the analysis show that with few exceptions burial patterns and the demographic picture of the Plains are quite stable over time, although differences are found in metric and non-metric variations in both the time and space continua. The analysis further shows that certain anomalous conditions in the skeleton appear to be much more prevalent inArchaic material than in recent material from the same area. The results finally suggest that Archaic people in the demographic and burial practice continua are quite similar to later populations, at least through Middle Mississippian populationsin the Plains.     

The Berg-Purcell Limit Revisited

Biological systems often have to measure extremely low concentrations of chemicals with high precision. When dealing with such small numbers of molecules, the inevitable randomness of physical transport processes and binding reactions will limit the precision with which measurements can be made. An important question is what the lower bound on the noise would be in such measurements. Using the theory of diffusion-influenced reactions, we derive an analytical expression for the precision of concentration estimates that are obtained by monitoring the state of a receptor to which a diffusing ligand can bind. The variance in the estimate consists of two terms, one resulting from the intrinsic binding kinetics and the other from the diffusive arrival of ligand at the receptor. The latter term is identical to the fundamental limit derived by Berg and Purcell (Biophys. J., 1977), but disagrees with a more recent expression by Bialek and Setayeshgar. Comparing the theoretical predictions against results from particle-based simulations confirms the accuracy of the resulting expression and reaffirms the fundamental limit established by Berg and Purcell.     

The ``hitchhiking Effect'''' Revisited

The number of selectively neutral polymorphic sites in a random sample of genes can be affected by ancestral selectively favored substitutions at linked loci. The degree to which this happens depends on when in the history of the sample the selected substitutions happen, the strength of selection and the amount of crossing over between the sampled locus and the loci at which the selected substitutions occur. This phenomenon is commonly called hitchhiking. Using the coalescent process for a random sample of genes from a selectively neutral locus that is linked to a locus at which selection is taking place, a stochastic, finite population model is developed that describes the steady state effect of hitchhiking on the distribution of the number of selectively neutral polymorphic sites in a random sample. A prediction of the model is that, in regions of low crossing over, strongly selected substitutions in the history of the sample can substantially reduce the number of polymorphic sites in a random sample of genes from that expected under a neutral model.     

The Northwest Passage Revisited

The Chinese annual fishing ban in the northwestern area of the South China Sea has been a cause for tension between Vietnam and China in recent years. This article advocates for the replacement of this unilateral fishing ban with a bilateral network of marine protected areas between China and Vietnam. Such a network, if properly implemented, could not only help to preserve the living resources of the South China Sea, but also contribute toward decreasing the tension between the two countries.