scholarly journals Shrub, Scrub, and Grass: The Importance of Shrubland and Grassland Plant Communities to the Diet of the Late Prehistoric (A.D. 900-1535) Hunter-Gatherers of the Eastern Trans-Pecos Region of Texas

2014 ◽  
Author(s):  
Casey Riggs
Keyword(s):  
Plant Communities ◽  
Analytical Techniques ◽  
Landscape Scale ◽  
Late Prehistoric ◽  
Hunter Gatherers ◽  
Ecological Sites ◽  
Ecological Site ◽  
The Past ◽  
Botanical Diversity ◽  
Degree Of Similarity

The Eastern Trans-Pecos archeological region of Texas is an area rich in botanical diversity, a resource heavily utilized by both prehistoric and historic hunter-gatherers. A comparison of four paleoethnobotanical investigations of archeological sites dating to the Late Prehistoric Era (A.D. 900-1535) with ethnobotanical information of the Mescalero Apache reveal that the botanical component of prehistoric and historic diets have been similar for the past 1,000 years. Differences in the degree of similarity can be contributed to differential preservation and analytical techniques. Further, ecological sites from the Ecological Site Information System are demonstrated as a novel and useful tool for landscape-scale archeological analysis.

Predicting fire-based perennial bunchgrass mortality in big sagebrush plant communities

2015 ◽  
Vol 24 (4) ◽  
pp. 527 ◽  
Author(s):  
Chad S. Boyd ◽  
Kirk W. Davies ◽  
April Hulet
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Perennial Grass ◽  
Basal Area ◽  
Grass Species ◽  
Individual Plant ◽  
Ecological Sites ◽  
Big Sagebrush ◽  
Ecological Site ◽  
Fire Characteristics

Maintenance and post-fire rehabilitation of perennial bunchgrasses is important for reducing the spread of exotic annual grass species in big sagebrush plant communities. Post-fire rehabilitation decisions are hampered by a lack of tools for determining extent of fire-induced perennial grass mortality. Our objective was to correlate post-fire characteristics with perennial bunchgrass mortality at the plant and plant community scales. We recorded basal area, percent char, depth of burn and soil colour for 174 bunchgrasses across four ecological sites after a 65 000 ha wildfire in south-east Oregon and assessed plant mortality. Mortality was correlated with post-fire soil colour and ecological site; soil colours (black and grey) associated with pre-fire shrub presence had up to five-fold higher mortality than brown soils typical of interspace locations. Models incorporating depth of burn and soil colour correctly predicted mortality for 90% of individual plants; cover of brown soil explained 88% of the variation in bunchgrass mortality at the plant community scale. Our results indicate that soil colour and depth of burn are accurate predictors of bunchgrass mortality at individual plant and plant community scales and could be used to spatially allocate post-fire bunchgrass rehabilitation resources.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Second international scientific conference «Present fundamental problems of vegetation classification» (Yalta, 15–20 September 2019)

2019 ◽  
pp. 135-142
Author(s):  
K. V. Ivanova ◽  
A. M. Lapina ◽  
V. V. Neshataev
Keyword(s):  
Plant Communities ◽  
National Archive ◽  
Botanical Garden ◽  
Vegetation Classification ◽  
Scientific Conference ◽  
Scientific Journals ◽  
Time Dynamics ◽  
The Past ◽  
Research Organizations

The 2nd international scientific conference «Fundamental problems of vegetation classification» took place at the Nikitskiy Botanical Garden (Yalta, Republic of Crimea, Russia) on 15–20 September 2019. There were 56 participants from 33 cities and 43 research organizations in Russia. The conference was mostly focused on reviewing the success in classification of the vegetation done by Russian scientists in the past three years. The reports covered various topics such as classification, description of new syntaxonomical units, geobotanical mapping for different territories and types of vegetation, studies of space-time dynamics of plant communities. The final discussion on the last day covered problems yet to be solved: establishment of the Russian Prodromus and the National archive of vegetation, complications of higher education in the profile of geobotany, and the issue of the data leakage to foreign scientific journals. In conclusion, it was announced that the 3rd conference in Nikitskiy Botanical Garden will be held in 2022.

Introduction

2018 ◽  
Author(s):  
Gianfranco Pacchioni
Keyword(s):  
Industrial Revolution ◽  
Homo Sapiens ◽  
Modern Society ◽  
Full Time ◽  
Human Race ◽  
Hunter Gatherers ◽  
The Past ◽  
The World ◽  
The Universe ◽  
Radical Transformation

About 10,000 years ago, at the beginning of the agriculturalrevolution, on the whole earth lived between 5 and 8 million hunter-gatherers, all belonging to the Homo sapiens species. Five thousand years later, freed from the primary needs for survival, some belonging to that species enjoyed the privilege of devoting themselves to philosophical speculation and the search for transcendental truths. It was only in the past two hundred years, however, with the advent of the Industrial Revolution, that reaping nature’s secrets and answering fundamental questions posed by the Universe have become for many full-time activities, on the way to becoming a real profession. Today the number of scientists across the globe has reached and exceeded 10 million, that is, more than the whole human race 10,000 years ago. If growth continues at the current rate, in 2050 we will have 35 million people committed full-time to scientific research. With what consequences, it remains to be understood. For almost forty years I myself have been concerned with science in a continuing, direct, and passionate way. Today I perceive, along with many colleagues, especially of my generation, that things are evolving and have changed deeply, in ways unimaginable until a few years ago and, in some respects, not without danger. What has happened in the world of science in recent decades is more than likely a mirror of a similar and equally radical transformation taking place in modern society, particularly with the advent ...

Landscape-scale disturbances and regeneration in semi-arid woodlands of southwestern Australia

1994 ◽  
Vol 1 (3) ◽  
pp. 214 ◽  
Author(s):  
Colin J. Yates ◽  
Richard J. Hobbs ◽  
Richard W. Bell
Keyword(s):  
Tree Mortality ◽  
Landscape Scale ◽  
Eucalyptus Species ◽  
Natural Ecosystems ◽  
Fragmented Landscapes ◽  
The Past ◽  
Adult Tree ◽  
Western Australian ◽  
Semi Arid

Woodlands dominated by Eucalyptus salmonophloia occur both in the fragmented landscapes of the Western Australian wheatbelt and in the adjacent unfragmented goldfields area. We examined the responses of the unfragmented woodlands to landscape-scale disturbances caused by fire, floods, windstorms and drought. Sites known to have experienced disturbances of these types over the past 50 years all had cohorts of sapling-stage E. salmonophloia and other dominant Eucalyptus species. Sites disturbed either by fire, flood or storm during 1991-92 displayed adult tree mortality and extensive seedling establishment, although rates of establishment and survival varied between sites. No regeneration was observed at equivalent undisturbed sites. These results indicate that landscape-scale disturbances of several types are important drivers of the dynamics of these semi-arid woodlands. Lack of regeneration of fragmented woodlands in the wheatbelt is likely to be due to changed disturbance regimes coupled with altered physical and biotic conditions within remnants. We argue that it may be difficult to identify processes which are important for the long-term persistence of natural ecosystems in fragmented landscapes without reference to equivalent unfragmented areas.

scholarly journals Conservation of the group Piperia (Orchidaceae) and associated plant communities

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Robert Lauri
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Human Activity ◽  
Mediterranean Climate ◽  
The Past ◽  
The Mediterranean

The conservation and protection of California native orchids has not been a large focus recently. All California native orchids are terrestrial and many are associated with forest and woodland plant com- munities. However, a number are associated with the Mediterranean Climate plant community known as Chaparral; this includes at least three Piperia Rydb. species. Many Piperia populations and associated Chaparral plant communities have been impacted by human activity over the past several decades, howev- er, there is very little documentation regarding the size, and overall impact to the populations. 

Evaluation of AMB Turbomachinery Auxiliary Bearings

1999 ◽  
Vol 121 (2) ◽  
pp. 156-161 ◽  
Author(s):  
R. G. Kirk
Keyword(s):  
Transient Response ◽  
Analytical Techniques ◽  
Contact Forces ◽  
Active Magnetic Bearings ◽  
Low Loss ◽  
The Past ◽  
Compressor Rotor ◽  
Auxiliary Bearing ◽  
On Line ◽  
Proper Design

The use of active magnetic bearings (AMB) for turbomachinery has experienced substantial growth during the past two decades. The advantages for many applications make AMB’s a very attractive solution for potentially low loss and efficient support for both radial and thrust loads. New machinery must be shop tested prior to shipment to the field for installation on-line. For AMB turbomachinery, one additional test is the operation of the auxiliary drop or overload bearings. A major concern is ability of the selected auxiliary bearing to withstand the contact forces following an at speed rotor drop. The proper design of AMB machinery requires the calculation of the anticipated loading for the auxiliary bearings. Analytical techniques to predict the rotor transient response are reviewed. Results of transient response evaluation of a full-size compressor rotor are presented to illustrate some of the important parameters in the design for rotor drop.

scholarly journals A Review of In Situ Isotopic Studies of the Oklo and Bangombé Natural Fission Reactors Using Microbeam Analytical Techniques

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1060
Author(s):  
Hiroshi Hidaka
Keyword(s):  
Nuclear Reactions ◽  
Fission Products ◽  
Analytical Techniques ◽  
Laser Probe ◽  
The Past ◽  
Isotopic Analyses ◽  
Isotopic Studies ◽  
Reactor Materials ◽  
Fission Reactors

Isotopic analyses of elements in the natural reactor materials have often been performed to understand the distribution behaviors of the fission products and to evaluate the function of nuclear reactions since the first discovery of a natural reactor in 1972. Several types of unique microminerals, including significant amounts of fission products, have been found in and around the Oklo and the Bangombé natural reactors. In the past two decades, microbeam techniques using ion and laser probe facilities have been effectively applied for the in situ isotopic analyses of individual microminerals to investigate the migration behaviors of fissiogenic radioisotopes produced in the reactors. This paper presents a review of interpretations of the isotopic results of microminerals found in and around the natural reactors.

A site-based approach to delivering rangeland ecosystem services

2011 ◽  
Vol 33 (2) ◽  
pp. 99 ◽  
Author(s):  
Joel Brown ◽  
Neil MacLeod
Keyword(s):  
Ecosystem Services ◽  
Multiple Scales ◽  
Soil Surface ◽  
Wildlife Habitat ◽  
Climate Mitigation ◽  
Ecological Sites ◽  
Ecological Site ◽  
State And Transition Model ◽  
A Site

Rangeland ecosystems are capable of providing an array of ecosystem services important to the wellbeing of society. Some of these services (e.g. meat, fibre) are transported to markets and their quantity, quality and value are established via a set of widely accepted standards. Other services (e.g. climate mitigation, water quality, wildlife habitat) do not leave the land, but are, in fact, most valuable when they remain in situ. Determining their quantity, quality and value presents a challenge that must be met if there is to be a credible, accessible ecosystem services market for rangelands. In this paper we describe some of the ecosystem services that may be extracted from rangelands, discuss their unique ecological nature and relate those unique ecological properties to soil and vegetation attributes that can serve as a basis for measurement, both quality and quantity. We suggest the use of a soil/vegetation-based system in which similar climate, geomorphology and edaphic properties are grouped into ecological sites based on their response to disturbance. Within each ecological site, a unique state and transition model describes the dynamics of vegetation and soil surface properties, provides state indicators (vegetation structure, soil properties), predicts ecosystem services that may be derived at multiple scales, and organises information related to management to achieve ecosystem service objectives, including sustainability.

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