scholarly journals Magnetic characteristics and palaeoenvironment reconstructions over the past 6200 years of Lake Tianchi of Liupan Mountain

2013 ◽  
Vol 25 (5) ◽  
pp. 756-764
Author(s):  
ZHANG Xinjia ◽  
◽  
SUN Huiling ◽  
WU Duo ◽  
ZHANG Xiaonan ◽  
...  
Keyword(s):  
Magnetic Characteristics ◽  
The Past ◽  
Liupan Mountain

scholarly journals Green Synthesis of Magnetic Iron Oxide Nanoparticle for Antibacterial Activity: A Review

2021 ◽  
Vol 64 (2) ◽  
pp. 202-210
Author(s):  
Muhammad Isa Khan ◽  
Aliza Zahoor ◽  
Tahir Iqbal ◽  
Abdul Majid ◽  
Mohsin Ijaz
Keyword(s):  
Iron Oxide ◽  
Green Synthesis ◽  
Biomedical Applications ◽  
Synthesis Method ◽  
Antibacterial Activities ◽  
Magnetic Characteristics ◽  
Iron Oxide Nanoparticle ◽  
The Past ◽  
Wide Range ◽  
Oxide Nanoparticle

  Recently, different researchers find nanoparticles as an auspicious alternative to antibacterial agents due to their antibacterial behaviour. This antibacterial behaviour contributes in many biomedical applications including; tissue engineering, drug and gene delivery and, imaging. Furthermore, iron oxide nanoparticle gains much importance due to their magnetic characteristics and wide range of application. Iron oxide nanoparticle (IONPs) have exhibits great potential against bacteria. During the past decade, various routes were developed to synthesize iron oxide nanoparticle with suitable size and composition. This article reviews the recent iron oxide nanoparticle obtained by green synthesis with a focus on their response to antibacterial activities. The iron nanoparticles synthesized by green synthesis method has accumulated a vital attention over the last couple of years due to their unique characteristic as it makes sure environmental friendly, nontoxic and safe reagents.

Deducing the role of eolian dust sedimentation during soil forming periods on mineral magnetic records and its implications for paleoclimate reconstructions

2020 ◽  
Author(s):  
Diana Jordanova ◽  
Neli Jordanova
Keyword(s):  
Grain Size ◽  
Conceptual Model ◽  
Climate Models ◽  
Soil Depth ◽  
Soil Formation ◽  
Magnetic Characteristics ◽  
Magnetic Fraction ◽  
Maximum Enhancement ◽  
The Past ◽  
Terrestrial Environments

<p>Obtaining reliable global and regional records of the past climatic changes during the glacial Pleistocene is of prime importance for building up consistent climate models of the near and far future. Magnetic signature along sequences of alternating loess and (paleo)soil units from the terrestrial environments is considered as semi-continuous record of climate change in the geological past. However, soil formation in aeolian landscapes may occur under different and changing conditions of dust sedimentation. Viewing from this standpoint the depth variations of several rock magnetic characteristics along profiles of Holocene soils from low Danube area allowed us to establish a set of criteria for identification of the past regimes of aeolian sedimentation persisted during the soil forming periods. A conceptual model for the time evolution of the grain size of the pedogenic magnetic fraction  with soil depth is proposed,  which is build upon  the mechanism of soil formation – accretional or  stable land surfaces,  or a combination of the two. According to the proposed conceptual model, discrimination between accretional soils and soils developed without dust additions during soil forming period can be done. Accretional soils are characterized by parallel changes in grain size sensitive magnetic proxies. Soils, developed at stable landscape conditions show gradation of the depths at which maximum enhancement of various proxies occurs with deepest occurrence of the maximum in frequency dependent magnetic susceptibility, followed by depth of maximum anhysteretic susceptibility and the normalized anhysteretic to isothermal remanence acquired at 100mT field. It is shown that the mean coercivity of the pedogenic component of accretional soils is higher than that of soils developed without eolian input at equal temperature conditions because of the soils’ thermal gradient and different depths, at which pedogenic minerals form in the two settings.</p>

scholarly journals Significance of the Ukrainian loess-palaeosol sequences for Pleistocene climate reconstructions: rock magnetic, palaeosol and pollen proxies

2021 ◽  
Vol 43 (3) ◽  
pp. 3-26
Author(s):  
D. V. Hlavatskyi ◽  
N.P. Gerasimenko ◽  
V.G. Bakhmutov ◽  
O.S. Bonchkovskyi ◽  
I.B. Poliachenko ◽  
...  
Keyword(s):  
Magnetic Characteristics ◽  
Magnetic Parameters ◽  
The Past ◽  
Climate Reconstructions ◽  
Pleistocene Climate ◽  
Wide Range ◽  
Normal Polarity ◽  
Loess Deposits ◽  
Magnetic Proxies ◽  
Soil Unit

Variations of rock magnetic parameters in loess-palaeosol sequences, related to climatic and environmental conditions during their formation, are a powerful tool for palaeoclimate reconstruction. Combined enviromagnetic study of loess deposits in Ukraine and its assessment for the palaeoreconstruction purposes are carried out in the framework of the National Research Foundation of Ukraine project 2020.02/0406 ‘Magnetic proxies of palaeoclimatic changes in the loess-palaeosol sequences of Ukraine’. Environmental/climatic reconstructions of the past are fulfilled using a significant number of palaeoindicators: morphology and lithological properties of palaeosols and loesses, their pollen assemblages and a wide range of magnetic characteristics. In this paper, we present a multi-proxy approach to palaeoenvironmental reconstructions, and introduce preliminary results obtained from magnetic susceptibility of loess-palaeosol sequences in the northern (at Vyazivok), central (Stari Kaydaky) and southern (Roksolany) parts of the Ukrainian loess belt. The amplitudes of palaeoclimate change established using magnetic proxies are well correlated with the lithological, palaeopedological and palynological patterns of the sites, and with the global oxygen-isotope scale (MIS). Ongoing studies of the Stari Kaydaky section confirm the correlation of the Upper Zavadivka (S3) soil unit and Lower Zavadivka (S4) soil unit with MIS 9 and MIS 11, respectively (this was proved earlier at the Vyazivok and Roksolany sites). The underlying Lubny (S5) pedocomplex likely corresponds to MIS 13, and the Martonosha (S6) pedocomplex to MIS 15. Palaeomagnetic investigations at Stari Kaydaky have not so far reached the Lower Shyrokyne unit, in which the Matuyama—Brunhes boundary has been detected at Roksolany and Vyazivok. The Upper Shyrokyne (S7S1) palaeosol unit has normal polarity and is preliminarily correlated with MIS 17.

scholarly journals Magnetic higher-mass stars in the early stages of their evolution

2013 ◽  
Vol 9 (S302) ◽  
pp. 70-79
Author(s):  
Jason H. Grunhut ◽  
E. Alecian
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Main Sequence ◽  
Magnetic Characteristics ◽  
Lower Mass ◽  
Surface Magnetic Field ◽  
The Past ◽  
Ordered Fields ◽  
Stellar Formation ◽  
Weak Fields

AbstractOver the past decade, significant investigations have been made through the use of high-resolution spectropolarimetry to probe the surface magnetic field characteristics of young higher-mass (M ≳ 1.5 M⊙) stars from pre-main sequence to zero-age main sequence evolutionary phases. The results of these observational campaigns suggest that these young higher-mass stars host similar magnetic properties to their main sequence descendants - strong, stable, globally-ordered fields that are detected in approximately 10 percent of all stars. This strongly contrasts with lower-mass stars, where it is generally accepted that a solar-like dynamo is in operation that generates more complex, globally-weak fields that are ubiquitous. The consensus is magnetic fields in higher-mass stars are fossil remnants of a magnetic field present in the molecular cloud, or generated very early during stellar formation. This review discusses the spectropolarimetric observations of higher-mass stars and how these observations have guided our current understanding of the magnetic characteristics of young higher-mass stars.

Observations of the continuum near the galactic centre

1967 ◽  
Vol 31 ◽  
pp. 405
Author(s):  
F. J. Kerr
Keyword(s):  
Galactic Centre ◽  
The Past ◽  
Centre Region ◽  
The Continuum

A continuum survey of the galactic-centre region has been carried out at Parkes at 20 cm wavelength over the areal11= 355° to 5°,b11= -3° to +3° (Kerr and Sinclair 1966, 1967). This is a larger region than has been covered in such surveys in the past. The observations were done as declination scans.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

On The Possibility of an Autonomous History of Modern Southeast Asia

1961 ◽  
Vol 2 (2) ◽  
pp. 73-105 ◽  
Author(s):  
John R. W. Small
Keyword(s):  
Southeast Asia ◽  
Contemporary History ◽  
The Past ◽  
History Of

It is generally accepted that history is an element of culture and the historian a member of society, thus, in Croce's aphorism, that the only true history is contemporary history. It follows from this that when there occur great changes in the contemporary scene, there must also be great changes in historiography, that the vision not merely of the present but also of the past must change.

Stellar Evolution

1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild
Keyword(s):  
Solar System ◽  
Stellar Evolution ◽  
Space Craft ◽  
New Techniques ◽  
Substantial Body ◽  
Individual Stars ◽  
The Past ◽  
Evolution Of Galaxies ◽  
History Of ◽  
Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

Novae in the Magellanic Clouds

1979 ◽  
Vol 46 ◽  
pp. 96-101
Author(s):  
J.A. Graham
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
University Of Michigan ◽  
The Past ◽  
Spectroscopic Information ◽  
Objective Prism ◽  
The University ◽  
Small Cloud ◽  
Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

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