Fertility and the Development of Agriculture in the Prehistoric Midwest

1986 ◽  
Vol 51 (3) ◽  
pp. 528-546 ◽  
Author(s):  
Jane E. Buikstra ◽  
Lyle W. Konigsberg ◽  
Jill Bullington
Keyword(s):  
Population Increase ◽  
Fertility Rates ◽  
Juvenile Mortality ◽  
Regional Population ◽  
Key Variables ◽  
Standard Life ◽  
Central Illinois ◽  
Preparation Techniques ◽  
Relative Fertility ◽  
Significant Increment

In this article we develop and apply a method for estimating fertility in paleodemographic study. The proportion D30+/D5+, generated from standard life table calculations, is used to estimate relative fertility rates for eight Woodland and Mississippian populations represented by skeletal series from west-central Illinois. The inferred pattern of fertility increase through time is then considered in the context of key variables that define diet, technology, and sedentism. We conclude that changes in diet or food preparation techniques are implicated in this demographic change. The absence of a significant increment in juvenile mortality in association with the elevated fertility rates suggests that these changes in fertility explain the regional population increase previously inferred from mortuary and habitation site densities.

El Indígeno and High-Altitude Human Occupation in the Southern Andes, Mendoza (Argentina)

2016 ◽  
Vol 27 (1) ◽  
pp. 96-114 ◽  
Author(s):  
Gustavo Neme
Keyword(s):  
High Altitude ◽  
Radiocarbon Dating ◽  
The Other ◽  
Population Increase ◽  
Human Occupation ◽  
Southern Andes ◽  
Central Argentina ◽  
Intensive Use ◽  
Regional Population ◽  
Marginal Environment

The site El Indígeno contains the greatest known concentration of hunter-gatherer residential features in the southern Andes. Located at 3,300 m asl in a meadow in the Cordillera of west-central Argentina, the site is notable for its 133 habitation structures, that—when considered along with the other characteristics of the site—represent an anomalous but perhaps not entirely unexpected adaptation to the highest altitude environment in the region. Based on radiocarbon dating and artifact typologies, the site was occupied between ca. 800 and 1500 B.P. It consequently represents the latest step in the indigenous colonization of what is arguably the most marginal environment in the region. This chronology suggests that the site was occupied when nearby lowland regions were under their most intensive use and during a time when new resources were incorporated into the high-altitude hunter-gatherer diet. In this article I report on research conducted at El Indigeno and compare the results of these studies to the regional record, ultimately concluding that regional population increase affiliated with the spread of increasingly complex socioeconomic systems most parsimoniously explains the intensive occupation of this large, high-altitude hunter-gatherer site.

Growth and Aggregation at Canyon Creek Ruin: Implications for Evolutionary Change in East-Central Arizona

1983 ◽  
Vol 48 (2) ◽  
pp. 290-315 ◽  
Author(s):  
Michael W. Graves
Keyword(s):  
Resource Constraints ◽  
Natural Increase ◽  
Population Increase ◽  
Logistic Growth ◽  
East Central ◽  
Tree Ring Data ◽  
Region I ◽  
Construction Activity ◽  
Regional Population ◽  
Central Arizona

Tree-ring data from the Canyon Creek Ruin, east-central Arizona, are analyzed to evaluate two competing interpretations of pueblo growth at this well-preserved cliff dwelling. Despite an anomalous dating pattern, a logistic model best describes pueblo growth. Room construction activity is linked to population increase, which, in turn, may be divided into two varieties: natural increase, and immigration of households into the settlement. Logistic growth also accounts for population increase within the larger area of the Grasshopper region. I review the processes promoting both local and regional population increase, as well as subsequent abandonment of the mountains of Arizona. I suggest that rapid depopulation may have occurred after A.D. 1375 because late prehistoric communities lost access to nonlocal goods that had previously allowed populations to increase beyond local resource constraints.

Opportunities & risks associated with global glacial meltwater changes and regional population growth from 1980 to 2100

2020 ◽  
Author(s):  
Bo Su ◽  
Cunde Xiao ◽  
Deliang Chen
Keyword(s):  
Population Growth ◽  
Large Scale ◽  
Environmental Changes ◽  
Population Increase ◽  
Mountain Glacier ◽  
Ecosystem Integrity ◽  
Glacial Meltwater ◽  
Mitigation And Adaptation ◽  
The World ◽  
Regional Population

<p>Mountain glacier is an indispensable supplier and modulator of freshwater to human’s sustenance in extensive cold and arid areas of the world. Melt waters from glaciers are widely used for ecosystem integrity, agricultural irrigation, hydropower operation, domestic and industrial activities. Under the background of global environmental changes such as global warming and regional population growth, linking climate-related glacio-hydrological changes to regional population growth is of the essence. However, a global assessment on opportunities/risks caused by glacial meltwater changes and population growth has not been presented until now. In this study, the population changes in glacier-fed area (GFA) for historical (1980-2015) and future (2010-2100) periods at the global, continental, national and basin scales were first mapped. Then, the opportunities/risks associated with population growth and glacier meltwater changes during 1980-2100 in 42 large-scale glacierized drainage basins with a minimum population of 10 thousand in 2015 were analyzed. Results reveal that the population living in the world’s GFA was 2030 million in 2015 and it was rapidly increased from 1278 million in 1980. The total population in GFA would continue to increase until a maximum is reached (e.g. peak population will appear around 2060 under the intermediate pathway for mitigation and adaptation, i.e. SSP<sub>2</sub>), beyond which the population would gradually decline. The opportunities/risks vary across basins and decades. Both of them are greatest in the Indus River basin, where the increase in glacial meltwater can seasonally satisfy the basic needs of additional 87 million people from the 2000s to 2040s, but about 200 million would be exposed to severe water scarcity due to the decrease in glacial meltwater and the population increase after the 2040s. </p>

A Freeze Shadow Technique for the Preparation of Soft Paint Latexes for Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 314-315
Author(s):  
Earl R. Walter ◽  
Glen H. Bryant
Keyword(s):  
Sample Preparation ◽  
High Vacuum ◽  
Vacuum System ◽  
Latex Particles ◽  
New Methods ◽  
Diffusion Pump ◽  
Film Forming ◽  
Routine Basis ◽  
Distribution Studies ◽  
Preparation Techniques

With the development of soft, film forming latexes for use in paints and other coatings applications, it became desirable to develop new methods of sample preparation for latex particle size distribution studies with the electron microscope. Conventional latex sample preparation techniques were inadequate due to the pronounced tendency of these new soft latex particles to distort, flatten and fuse on the substrate when they dried. In order to avoid these complications and obtain electron micrographs of undistorted latex particles of soft resins, a freeze-dry, cold shadowing technique was developed. The method has now been used in our laboratory on a routine basis for several years.The cold shadowing is done in a specially constructed vacuum system, having a conventional mechanical fore pump and oil diffusion pump supplying vacuum. The system incorporates bellows type high vacuum valves to permit a prepump cycle and opening of the shadowing chamber without shutting down the oil diffusion pump. A baffeled sorption trap isolates the shadowing chamber from the pumps.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

Electron Microscopic Observation of Biological Specimens in Their Native State by Employing Cryogenic Techniques

1972 ◽  
Vol 30 ◽  
pp. 410-411 ◽  
Author(s):  
Tokio Nei ◽  
Haruo Yotsumoto ◽  
Yoichi Hasegawa ◽  
Yuji Nagasawa
Keyword(s):  
Electron Microscopic Observation ◽  
Surface Structures ◽  
Specimen Preparation ◽  
Native State ◽  
Electron Microscopic ◽  
Biological Specimen ◽  
Specimen Holder ◽  
Cold Stage ◽  
Preparation Techniques ◽  
Scanning Electron

In order to observe biological specimens in their native state, that is, still containing their water content, various methods of specimen preparation have been used, the principal two of which are the chamber method and the freeze method.Using its recently developed cold stage for installation in the pre-evacuation chamber of a scanning electron microscope, we have succeeded in directly observing a biological specimen in its frozen state without the need for such conventional specimen preparation techniques as drying and metallic vacuum evaporation. (Echlin, too, has reported on the observation of surface structures using the same freeze method.)In the experiment referred to herein, a small sliced specimen was place in the specimen holder. After it was rapidly frozen by freon cooled with liquid nitrogen, it was inserted into the cold stage of the specimen chamber.

High-Resolution Scanning Electron Microscopy of Biological Specimens

1988 ◽  
Vol 46 ◽  
pp. 186-187
Author(s):  
M. Müller ◽  
R. Hermann
Keyword(s):  
High Resolution ◽  
Freeze Drying ◽  
Room Temperature ◽  
Structural Information ◽  
Freeze Substitution ◽  
Critical Point Drying ◽  
Sem Study ◽  
Major Factors ◽  
Structural Preservation ◽  
Preparation Techniques

Three major factors must be concomitantly assessed in order to extract relevant structural information from the surface of biological material at high resolution (2-3nm).Procedures based on chemical fixation and dehydration in graded solvent series seem inappropriate when aiming for TEM-like resolution. Cells inevitably shrink up to 30-70% of their initial volume during gehydration; important surface components e.g. glycoproteins may be lost. These problems may be circumvented by preparation techniques based on cryofixation. Freezedrying and freeze-substitution followed by critical point drying yields improved structural preservation in TEM. An appropriate preservation of dimensional integrity may be achieved by freeze-drying at - 85° C. The sample shrinks and may partially collapse as it is warmed to room temperature for subsequent SEM study. Observations at low temperatures are therefore a necessary prerequisite for high fidelity SEM. Compromises however have been unavoidable up until now. Aldehyde prefixation is frequently needed prior to freeze drying, rendering the sample resistant to treatment with distilled water.

SEM Evaluation of Fluoride Pretreatment Effects on Acid-Etching of Caries-Like Enamel Lesions In Vitro

1981 ◽  
Vol 39 ◽  
pp. 474-475
Author(s):  
M. John Hicks
Keyword(s):  
Dental Enamel ◽  
Preventive Measure ◽  
Acid Etching ◽  
Distilled Water ◽  
Adhesive Resin ◽  
Fluoride Treatment ◽  
Treatment Groups ◽  
Pretreatment Effects ◽  
Preparation Techniques

Acid-etching of enamel surfaces has been performed routinely to bond adhesive resin materials to sound dental enamel as a caries-preventive measure. The effect of fluoride pretreatment on acid-etching of enamel has been reported to produce inconsistent and unsatisfactory etching patterns. The failure to obtain an adequate etch has been postulated to be due to fluoride precipitation products deposited on the enamel surface. The purpose of this study was to evaluate the effects of fluoride pretreatment on acid-etching of carieslike lesions of human dental enamel.Caries-like lesions of enamel were created in vitro on human molar and premolar teeth. The teeth were divided into two fluoride treatment groups. The specimens were exposed for 4 minutes to either a 2% Sodium Fluoride (NaF) solution or a 10% Stannous Fluoride (SnF2) solution. The specimens were then washed in deionized-distilled water. Each tooth was sectioned into four test regions. This was carried out to compare the effects of various time exposures (0 to 2 minutes) and differing concentrations (10 to 60% w/w) of phosphoric acid (H3PO4) on etching of caries-like lesions. Standard preparation techniques for SEM were performed on the specimens.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

Scanning tunneling microscopy of E. coli RNA polymerase deposited onto an Au substrate by an electrochemical process

1991 ◽  
Vol 49 ◽  
pp. 378-379
Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear
Keyword(s):  
Scanning Tunneling Microscope ◽  
Biological Sample ◽  
Substrate Surface ◽  
Electrochemical Process ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Tunneling Microscope ◽  
E Coli ◽  
Preparation Techniques

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.

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