scholarly journals Ground-Based Hyperspectral Characterization of Alaska Tundra Vegetation along Environmental Gradients

2013 ◽  
Vol 5 (8) ◽  
pp. 3971-4005 ◽  
Author(s):  
Marcel Buchhorn ◽  
Donald Walker ◽  
Birgit Heim ◽  
Martha Raynolds ◽  
Howard Epstein ◽  
...  
Keyword(s):  
Environmental Gradients ◽  
Tundra Vegetation

scholarly journals A remote sensing-based dataset to characterize the ecosystem functioning and functional diversity of a Biosphere Reserve: Sierra Nevada (SE Spain)

2020 ◽  
Author(s):  
Beatriz P. Cazorla ◽  
Javier Cabello ◽  
Andrés Reyes ◽  
Emilio Guirado ◽  
Julio Peñas ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Sierra Nevada ◽  
Ecosystem Functioning ◽  
Vegetation Index ◽  
Management Practices ◽  
Environmental Gradients ◽  
Environmental Data ◽  
Data Availability ◽  
Ecological Processes

Abstract. Conservation Biology faces the challenge of safeguarding the ecological processes that sustain biodiversity. Characterization and evaluation of these processes can be carried out through attributes or functional traits related to the exchanges of matter and energy between vegetation and the atmosphere. Nowadays, the use of satellite imagery provides useful methods to produce a spatially continuous characterization of ecosystem functioning and processes at regional scales. Our dataset characterizes the patterns of ecosystem functioning in Sierra Nevada (Spain) from the vegetation greenness dynamics captured through the spectral vegetation index EVI (Enhanced Vegetation Index) since 2001 to 2018 (product MOD13Q1.006 from MODIS sensor). First, we provided three Ecosystem Functional Attributes (EFAs) (i.e., descriptors of annual primary production, seasonality, and phenology of carbon gains), as well as their integration into a synthetic mapping of Ecosystem Functional Types (EFTs). Second, we provided two measures of functional diversity: EFT richness and EFT rarity. Finally, in addition to the yearly maps, we calculated interannual summaries, i.e., means and inter-annual variabilities. Examples of research and management applications of these data sets are also included to highlight the value of EFAs and EFTs to improve the understanding and monitoring ecosystem processes across environmental gradients. The datasets are available in two open-source sites (PANGAEA: https://doi.pangaea.de/10.1594/PANGAEA.904575 (Cazorla et al. 2019) and http://obsnev.es/apps/efts_SN.html), and bring to scientists, managers and the general public valuable information on the first characterization of the functional diversity at ecosystem level developed in a Mediterranean hotspot. Sierra Nevada represents an exceptional ecology laboratory of field conditions, where a long-term monitoring (LTER) program was established 10 years ago. The data availability on biodiversity, climate, ecosystem services, hydrology, land-use changes and management practices from Sierra Nevada, will allow to explore the relationships between these other environmental data and ecosystem functional data that we provide in this work.

scholarly journals Assessing the predation function via quantitative and qualitative interaction components

2020 ◽  
Author(s):  
Carlos Martínez-Núñez ◽  
Pedro J. Rey
Keyword(s):  
Pest Control ◽  
Environmental Gradients ◽  
Biotic Interactions ◽  
Community Level ◽  
Ecosystem Functions ◽  
Frequency Of Occurrence ◽  
Qualitative Interaction ◽  
Qualitative Component ◽  
Evolutionary Consequences

AbstractInteractions among organisms can be defined by two main features: a quantitative component (i.e. frequency of occurrence) and a qualitative component (i.e. success of the interaction).Measuring properly these two components at the community level, can provide a good estimate of the ecosystem functions mediated by biotic interactions. Although this approach has been frequently applied to evaluate the eco-evolutionary consequences of mutualistic relationships, it has never been extended to the predation function and the associated pest control ecosystem service.Here, we introduce a simple measure that accounts for the quantitative and the qualitative components of predation interactions, and facilitates a precise characterization of this ecosystem function at the community level, while accounting for variations at species and individual levels.This measure arises as a fine indicator of predation pressure, and provides great opportunities to better understand how different components of predation and pest control potential vary across environmental gradients.

Spatial characterization of environmental gradients in a coastal lagoon, Chincoteague Bay

2007 ◽  
Vol 30 (6) ◽  
pp. 959-977 ◽  
Author(s):  
Thomas R. Allen ◽  
Harri T. Tolvanen ◽  
George F. Oertel ◽  
George M. McLeod
Keyword(s):  
Coastal Lagoon ◽  
Environmental Gradients ◽  
Spatial Characterization ◽  
Chincoteague Bay

Vegetation patterns and environmental gradients in coastal meadows on the Yukon–Kuskokwim delta, Alaska

1991 ◽  
Vol 69 (7) ◽  
pp. 1616-1627 ◽  
Author(s):  
Karen L. Kincheloe ◽  
Robert A. Stehn
Keyword(s):  
Plant Communities ◽  
Environmental Variables ◽  
Environmental Gradients ◽  
Vascular Plant ◽  
Detrended Correspondence Analysis ◽  
Vegetation Patterns ◽  
Intertidal Mudflat ◽  
Tundra Vegetation ◽  
Species Analysis ◽  
Coastal Meadows

Tundra vegetation and environmental variables were sampled on the Yukon–Kuskokwim delta in western Alaska. On transects extending from intertidal mudflat to upland tundra, we estimated cover by vascular plant species, soil moisture, salinity, relative elevation, depth to permafrost, and distance upriver from the coast. Two-way indicator species analysis (TWINSPAN) classified 21 communities. Ordination by detrended correspondence analysis (DECORANA) revealed a gradient correlated with the combination of elevation, permafrost depth, and salinity along the first axis for both upriver and downriver transects. Key words: Alaska, ordination, plant communities, salt marsh, tundra, Yukon–Kuskokwim delta.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

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.

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