Teleseismic studies of the Canadian landmass: Lithoprobe and its legacyThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent.ESS Contribution 20090305.

2010 ◽  
Vol 47 (4) ◽  
pp. 445-461 ◽  
Author(s):  
M.G. Bostock ◽  
D.W. Eaton ◽  
D.B. Snyder
Keyword(s):  
British Columbia ◽  
Subduction Zones ◽  
Canadian Shield ◽  
Plate Motion ◽  
Special Issue ◽  
The Past ◽  
Structure And Dynamics ◽  
Slave Province ◽  
Shallow Subduction

Although teleseismic research was only modestly represented within the Lithoprobe program, the analysis of deeper lithospheric structure beneath Canada using teleseismic methods has intensified in the past decade. This development is due in large part to a legacy of improved understanding of shallower lithospheric structures afforded by Lithoprobe. Most recent teleseismic experiments have been conducted in regions lying within Lithoprobe transects and coverage is particularly good in the Slave Province, southern and eastern Ontario, and southwestern British Columbia. A number of key results have arisen out of this collective body of work. Studies on the Slave Province and environs have placed strong constraints on the origin of the high-velocity continental root that underlies most of the Canadian Shield. Fine-scale, anisotropic stratigraphy in this region has been definitively tied to underplated lithosphere, indicating that shallow subduction has played a fundamental role in craton stabilization. Modification of continental lithosphere by the underlying convecting mantle has been extensively documented in the southeastern Canadian Shield and Slave Province, yielding insights into the forces driving plate motion and those that induce intraplate volcanism. Teleseismic investigations in British Columbia point to the importance of water in controlling the structure and dynamics of subduction zones, but have rekindled controversy concerning the location and characterization of the downgoing oceanic plate.

scholarly journals Characterization of Exopolysaccharides Produced by Rhizobia Species

2015 ◽  
Vol 39 (6) ◽  
pp. 1566-1575 ◽  
Author(s):  
Tereza Cristina Luque Castellane ◽  
Alda Maria Machado Bueno Otoboni ◽  
Eliana Gertrudes de Macedo Lemos
Keyword(s):  
High Performance ◽  
Biological Properties ◽  
Reversed Phase ◽  
The Past ◽  
Structure And Dynamics ◽  
Key Factor ◽  
Reactive Groups ◽  
Potential Applications ◽  
Species Specific

ABSTRACT Increasing attention has been given, over the past decades, to the production of exopolysaccharides (EPS) from rhizobia, due to their various biotechnological applications. Overall characterization of biopolymers involves evaluation of their chemical, physical, and biological properties; this evaluation is a key factor in understanding their behavior in different environments, which enables researchers to foresee their potential applications. Our focus was to study the EPS produced by Mesorhizobium huakuii LMG14107, M. loti LMG6125, M. plurifarium LMG11892,Rhizobium giardini bv. giardiniH152T, R. mongolense LMG19141, andSinorhizobium (= Ensifer)kostiense LMG19227 in a RDM medium with glycerol as a carbon source. These biopolymers were isolated and characterized by reversed-phase high-performance liquid chromatography (RP-HPLC), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopies. Maximum exopolysaccharide production was 3.10, 2.72, and 2.50 g L-1for the strains LMG6125, LMG19227, and LMG19141, respectively. The purified EPS revealed prominent functional reactive groups, such as hydroxyl and carboxylic, which correspond to a typical heteropolysaccharide. The EPS are composed primarily of galactose and glucose. Minor components found were rhamnose, glucuronic acid, and galacturonic acid. Indeed, from the results of techniques applied in this study, it can be noted that the EPS are species-specific heteropolysaccharide polymers composed of common sugars that are substituted by non-carbohydrate moieties. In addition, analysis of these results indicates that rhizobial EPS can be classified into five groups based on ester type, as determined from the 13C NMR spectra. Knowledge of the EPS composition now facilitates further investigations relating polysaccharide structure and dynamics to rheological properties.

Soft matter research in India

2021 ◽  
Vol 34 (9) ◽  
pp. 090402
Author(s):  
Ranjini Bandyopadhyay ◽  
Jürgen Horbach
Keyword(s):  
Soft Matter ◽  
Soft Materials ◽  
Research Area ◽  
Experimental Investigations ◽  
Special Issue ◽  
Complex Flow ◽  
Research Papers ◽  
The Past ◽  
Biological Physics

Abstract Research on soft matter and biological physics has grown tremendously in India over the past decades. In this editorial, we summarize the twenty-three research papers that were contributed to the special issue on Soft matter research in India. The papers in this issue highlight recent exciting advances in this rapidly expanding research area and include theoretical studies and numerical simulations of soft and biological systems, the synthesis and characterization of novel, functional soft materials and experimental investigations of their complex flow behaviours.

scholarly journals An overview of meso-scale aerosol processes, comparison and validation studies from DRAGON networks

2017 ◽  
Author(s):  
Brent N. Holben ◽  
Jhoon Kim ◽  
Itaru Sano ◽  
Sony Mukai ◽  
Thomas F. Eck ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Satellite Remote Sensing ◽  
Global Network ◽  
Special Issue ◽  
Airborne Measurements ◽  
The Past ◽  
Meso Scale ◽  
Aerosol Properties

Abstract. The AErosol RObotic NETwork (AERONET) program over the past 24 years has provided highly accurate remote sensing characterization of aerosol optical and physical properties for an increasingly extensive geographic distribution that includes all continents and many island sites. The measurements and retrievals from the AERONET global network have addressed satellite and model validation needs very well, but there have been challenges in making comparisons to similar parameters from in situ surface and airborne measurements. Additionally, with improved spatial and temporal satellite remote sensing of aerosols, there is a need for higher spatial resolution ground-based remote sensing networks. An effort to address this need resulted in a number of field campaign networks called Distributed Regional Aerosol Gridded Observation Networks (DRAGONs) that were designed to provide a database for in situ and remote sensing comparison and analysis of local to meso-scale variability of aerosol properties. This paper describes the networks that that have contributed and will continue to contribute to that body of research. The research presented in this special issue illustrates the diversity of topics that has resulted from the application of data from these networks.

scholarly journals An overview of mesoscale aerosol processes, comparisons, and validation studies from DRAGON networks

2018 ◽  
Vol 18 (2) ◽  
pp. 655-671 ◽  
Author(s):  
Brent N. Holben ◽  
Jhoon Kim ◽  
Itaru Sano ◽  
Sonoyo Mukai ◽  
Thomas F. Eck ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Satellite Remote Sensing ◽  
Oceanic Island ◽  
Global Network ◽  
Mesoscale Variability ◽  
Special Issue ◽  
Airborne Measurements ◽  
The Past

Abstract. Over the past 24 years, the AErosol RObotic NETwork (AERONET) program has provided highly accurate remote-sensing characterization of aerosol optical and physical properties for an increasingly extensive geographic distribution including all continents and many oceanic island and coastal sites. The measurements and retrievals from the AERONET global network have addressed satellite and model validation needs very well, but there have been challenges in making comparisons to similar parameters from in situ surface and airborne measurements. Additionally, with improved spatial and temporal satellite remote sensing of aerosols, there is a need for higher spatial-resolution ground-based remote-sensing networks. An effort to address these needs resulted in a number of field campaign networks called Distributed Regional Aerosol Gridded Observation Networks (DRAGONs) that were designed to provide a database for in situ and remote-sensing comparison and analysis of local to mesoscale variability in aerosol properties. This paper describes the DRAGON deployments that will continue to contribute to the growing body of research related to meso- and microscale aerosol features and processes. The research presented in this special issue illustrates the diversity of topics that has resulted from the application of data from these networks.

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.

EDITORIAL: Migration and competitiveness: Japan and the United States

2013 ◽  
Vol 10 (2) ◽  
pp. 115-124
Author(s):  
Philip L. Martin
Keyword(s):  
United States ◽  
The United States ◽  
Variable Cost ◽  
Fixed Cost ◽  
Special Issue ◽  
Science And Engineering ◽  
The Past ◽  
Past Half Century ◽  
Key Sectors ◽  
Past Half

Japan and the United States, the world’s largest economies for most of the past half century, have very different immigration policies. Japan is the G7 economy most closed to immigrants, while the United States is the large economy most open to immigrants. Both Japan and the United States are debating how immigrants are and can con-tribute to the competitiveness of their economies in the 21st centuries. The papers in this special issue review the employment of and impacts of immigrants in some of the key sectors of the Japanese and US economies, including agriculture, health care, science and engineering, and construction and manufacturing. For example, in Japanese agriculture migrant trainees are a fixed cost to farmers during the three years they are in Japan, while US farmers who hire mostly unauthorized migrants hire and lay off workers as needed, making labour a variable cost.

Five Years and Count(er)ing: Memoir after Memoir

CounterText ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 26-32
Author(s):  
Norbert Bugeja
Keyword(s):  
Guest Editor ◽  
Arab Countries ◽  
National Museum ◽  
Terror Attack ◽  
Special Issue ◽  
The Past ◽  
Personal Perspectives ◽  
The Moment ◽  
Ongoing Project

In this retrospective piece, the Guest Editor of the first number of CounterText (a special issue titled Postcolonial Springs) looks back at the past five years from various scholarly and personal perspectives. He places particular focus on an event that took place mid-way between the 2011 uprisings across a number of Arab countries and the moment of writing: the March 2015 terror attack on the Bardo National Museum in Tunis, which killed twenty-two people and had a profound effect on Tunisian popular consciousness and that of the post-2011 Arab nations. In this context, the author argues for a renewed perspective on memoir as at once a memorial practice and a political gesture in writing, one that exceeds concerns of genre and form to encompass an ongoing project of political re-cognition following events that continue to remap the agenda for the region. The piece makes a brief final pitch for Europe's need to re-cognise, within those modes of ‘articulacy-in-difficulty’ active on its southern borders, specific answers to its own present quandaries.

Reframing the Sciences of the Long Eighteenth Century

2020 ◽  
Vol 50 (1-2) ◽  
pp. 58-66
Author(s):  
Giuliano Pancaldi
Keyword(s):  
Eighteenth Century ◽  
History Of Science ◽  
Science Policy ◽  
Special Issue ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
History Of ◽  
Long Eighteenth Century ◽  
Past Half

Here I survey a sample of the essays and reviews on the sciences of the long eighteenth century published in this journal since it was founded in 1969. The connecting thread is some historiographic reflections on the role that disciplines—in both the sciences we study and the fields we practice—have played in the development of the history of science over the past half century. I argue that, as far as disciplines are concerned, we now find ourselves a bit closer to a situation described in our studies of the long eighteenth century than we were fifty years ago. This should both favor our understanding of that period and, hopefully, make the historical studies that explore it more relevant to present-day developments and science policy. This essay is part of a special issue entitled “Looking Backward, Looking Forward: HSNS at 50,” edited by Erika Lorraine Milam.

Diatom- and Chironomid-Inferred Eutrophication of Bouchie Lake, British Columbia

2005 ◽  
Vol 40 (4) ◽  
pp. 418-430 ◽  
Author(s):  
Markus L. Heinrichs ◽  
Brian F. Cumming ◽  
Kathleen R. Laird ◽  
J. Sanford Hart
Keyword(s):  
British Columbia ◽  
Land Use Changes ◽  
Head Capsule ◽  
Relative Increase ◽  
Nutrient Concentrations ◽  
The Past ◽  
Nutrient Levels ◽  
Lower Head ◽  
Lower Oxygen ◽  
Historical Land Use

Abstract Diatom and chironomid analysis of sediments encompassing the past 400 years from Bouchie Lake, British Columbia, suggests two distinct periods of limnological conditions. Prior to 1950 AD, Fragilaria construens and F. pinnata are the most common diatom species, and Chironomus, Procladius and Tanytarsini dominate the chironomid record. Moderately low nutrient concentrations consistent with oligo-mesotrophic lakes are inferred. From 1950, the diatom assemblage is dominated by Stephanodiscus parvus, a eutrophic indicator, whereas the chironomid communities show a relative increase in littoral taxa coincident with lower head capsule abundance. Higher nutrient levels, specifically total phosphorus, which increased from 8 µg L-1 prior to 1950 to 20 µg L-1 currently, are coincident with midge communities indicative of lower oxygen concentrations. Observed biotic changes and nutrient levels inferred from the sediment core correspond to historical land-use changes.

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