scholarly journals The magnetic susceptibility of single crystals of zinc and cadmium

1928 ◽  
Vol 121 (787) ◽  
pp. 9-21 ◽  
Keyword(s):  
Energy Distribution ◽  
Small Mass ◽  
Metallic Ions ◽  
Free Electrons ◽  
Gaseous State ◽  
The Past ◽  
Electronic Spin ◽  
Great Progress ◽  
Made In ◽  
Paramagnetic Properties

During the past five years great progress has been made in the theory of the diamagnetic and paramagnetic properties of matter. Langevin’s theory of paramagnetism, long recognised as insufficient, has been replaced by a more general treatment due to B. Cabrera. The magnetism of metals for which no theory existed at all has been explained by W. Pauli as due to the spin of the free electrons contained in the volume V occupied by the metal. Owing to their enormous concentration in addition to their small mass, the electrons within the metal do not follow the ordinary laws for the gaseous state; in particular, the energy distribution is not Maxwellian. For a Maxwellian distribution, that is, for strongly decreasing energy with decreasing temperature, the electrons could not remain in the free state at low temperature, but would combine with the metallic ions between which they move. The electrons are instead subject to quantisation and the energy is distributed according to the principle of Pauli-Fermi. If ε k be the energy in the quantum state k , of one of the electrons contained in the volume V, ε m its spin, then there can be at the most up to G = 2 electrons representing this state, and then they must spin in opposite directions. Moreover, if mξ, mη, mζ are the components of the angular momentum of the electron along the three axes of the system of co-ordinates so that E = 1/2 mv 2 = 1/2 m (ξ 2 + η 2 + ζ 2 ), then there exist, in the interval between ε and ε + dε, 4πGV ( m/h ) 3 v 2 dv = 2πVG h -3 (2 m ) 3/2 ε1/2 dε possible states. Evidently the total energy will be E = Σ n k (ε k + ε m ), the only values for n , being either 0 or 1, with the condition that the total number N of electrons is N = Σ k n k . Now ε m , the energy due to the electron spin, is small compared with ε k and can be neglected in most problems. We may say that the state of the gas is defined if we know the most probable values of n k for the ε k , that is, whether n k is equal to 0 or 1 for a certain ε k . Owing to the presence of the electronic spin ε s = ± eh /4π mc (Bohr magneton) the energy distribution will be slightly changed when an external field H is applied. We have for the number of atoms with an orientation parallel to the field

An Integrative Approach to the Assessment and Treatment of Inflammatory Conditions

2017 ◽  
Author(s):  
Mark Liponis ◽  
Bettina Martin
Keyword(s):  
Integrative Approach ◽  
The Past ◽  
Inflammatory Conditions ◽  
Improved Outcomes ◽  
Targeted Treatments ◽  
Great Progress ◽  
Assessment And Treatment ◽  
The Many ◽  
Made In

The past two decades have seen great progress in recognizing the importance of inflammation in medicine. Increased focus on inflammation in both prevention and treatment has improved outcomes and quality of life in chronic diseases. Science has improved our understanding of inflammation’s many causes and effects on health, and many advances have been made in the availability of targeted therapeutic options for treating inflammation. This chapter gives an overview of recognizing the many causes of inflammation, its many targeted treatments strategies, and the questions that still surround it. It discusses several integrative approaches to reducing inflammation, including exercise, diet, and different strategies for managing sleep, mood, and stress, such as meditation and massage.

scholarly journals A Morphological and Histological Investigation of Imperfect Lungfish Fin Regeneration

2021 ◽  
Vol 9 ◽  
Author(s):  
Vivien Bothe ◽  
Igor Schneider ◽  
Nadia B. Fröbisch
Keyword(s):  
Tissue Regeneration ◽  
Molecular Mechanisms ◽  
Limb Regeneration ◽  
Body Parts ◽  
Serial Sections ◽  
Fin Regeneration ◽  
X Ray ◽  
The Past ◽  
Great Progress ◽  
Made In

Regeneration, the replacement of body parts in a living animal, has excited scientists for centuries and our knowledge of vertebrate appendage regeneration has increased significantly over the past decades. While the ability of amniotes to regenerate body parts is very limited, members of other vertebrate clades have been shown to have rather high regenerative capacities. Among tetrapods (four-limbed vertebrates), only salamanders show unparalleled capacities of epimorphic tissue regeneration including replacement of organ and body parts in an apparently perfect fashion. The closest living relatives of Tetrapoda, the lungfish, show regenerative abilities that are comparable to those of salamanders and recent studies suggest that these high regenerative capacities may indeed be ancestral for bony fish (osteichthyans) including tetrapods. While great progress has been made in recent years in understanding the cellular and molecular mechanisms deployed during appendage regeneration, comparatively few studies have investigated gross morphological and histological features of regenerated fins and limbs. Likewise, rather little is known about how fin regeneration compares morphologically to salamander limb regeneration. In this study, we investigated the morphology and histology of regenerated fins in all three modern lungfish families. Data from histological serial sections, 3D reconstructions, and x-ray microtomography scans were analyzed to assess morphological features, quality and pathologies in lungfish fin regenerates. We found several anomalies resulting from imperfect regeneration in regenerated fins in all investigated lungfish species, including fusion of skeletal elements, additional or fewer elements, and distal branching. The similarity of patterns in regeneration abnormalities compared to salamander limb regeneration lends further support to the hypothesis that high regenerative capacities are plesiomorphic for sarcopterygians.

scholarly journals Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

2021 ◽  
Vol 17 ◽  
pp. 2462-2476
Author(s):  
Yi Liu ◽  
Puying Luo ◽  
Yang Fu ◽  
Tianxin Hao ◽  
Xuan Liu ◽  
...  
Keyword(s):  
Reaction Mechanisms ◽  
Structural Motifs ◽  
Pyrrole Derivatives ◽  
The Past ◽  
Recent Advances ◽  
Functionalized Pyridine ◽  
Great Progress ◽  
Made In

Great progress has been made in the tandem annulation of enynes in the past few years. This review only presents the corresponding reactions of 1,3-enyne structural motifs to provide the functionalized pyridine and pyrrole derivatives. The functionalization reactions cover iodination, bromination, trifluoromethylation, azidation, carbonylation, arylation, alkylation, selenylation, sulfenylation, amidation, esterification, and hydroxylation. We also briefly introduce the applications of the products and the reaction mechanisms for the synthesis of corresponding N-heterocycles.

scholarly journals Khan Academy Videos in Chinese: A Case Study in OER Revision

2017 ◽  
Vol 18 (5) ◽  
Author(s):  
Allen Rao ◽  
John Hilton III ◽  
Sarah Harper
Keyword(s):  
Open Educational Resources ◽  
Educational Resources ◽  
The Past ◽  
Local Contexts ◽  
Great Progress ◽  
Open Courses ◽  
Khan Academy ◽  
Made In

<p class="3">Over the past decade, great progress has been made in improving the quality and availability of Open Educational Resources (OER). OER proponents often discuss the ability for users to revise and remix OER to make them more suitable for local contexts; however, much OER goes unmodified. This note from the field examines the efforts of NetEase Online Open Courses, a Chinese organization, to take more than two thousand Khan Academy videos and translate them into Chinese. We provide background on this initiative and also analyze site metrics to determine what type of use these derivative OER have received.</p>

Presidential Address

1913 ◽  
Vol 7 ◽  
pp. 1-24
Author(s):  
Archdeacon W. Cunningham
Keyword(s):  
Presidential Address ◽  
Young Men ◽  
British History ◽  
English History ◽  
Richard Iii ◽  
The Past ◽  
Great Progress ◽  
Made In

During the past year the Society has sustained one loss that overshadows all others. It is not for me to attempt to appreciate the value of the substantial contributions to the published sources of English history to which Mr. James Gairdner devoted himself so assiduously; I can only attempt to express the feeling which many of us here must share on the loss of our friend. I well remember the intense interest with which I read his ‘Life of Richard III.’ when it was first published in 1878, and the pleasure which I felt many years after in coming into contact with a man whom I admired so much. His constant kindliness and readiness to interest himself in and encourage the work of young men are not things to be readily forgotten. The chronicling of the blanks left in the roll of our officials and members is the saddest part of a President's duty. In my first address I expressed our sense of loss sustained through the death of Dr. Charles Gross; at this distance of time we can see more clearly than was possible four years ago how fruitful his work was. This year great progress has been made in the attempt to carry on the Bibliography of British History which he began, and during the last few weeks I have been impressed anew with the freshness and thoroughness of his studies, as I have been trying to look into and amplify the argument of his essay on Scottish Municipal History.

scholarly journals Elevating crop disease resistance with cloned genes

2014 ◽  
Vol 369 (1639) ◽  
pp. 20130087 ◽  
Author(s):  
Jonathan D. G. Jones ◽  
Kamil Witek ◽  
Walter Verweij ◽  
Florian Jupe ◽  
David Cooke ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Plant Disease Resistance ◽  
Soil Compaction ◽  
Crop Production ◽  
Resistance Mechanisms ◽  
Plant Diseases ◽  
The Past ◽  
Great Progress ◽  
Crop Disease ◽  
Made In

Essentially all plant species exhibit heritable genetic variation for resistance to a variety of plant diseases caused by fungi, bacteria, oomycetes or viruses. Disease losses in crop monocultures are already significant, and would be greater but for applications of disease-controlling agrichemicals. For sustainable intensification of crop production, we argue that disease control should as far as possible be achieved using genetics rather than using costly recurrent chemical sprays. The latter imply CO 2 emissions from diesel fuel and potential soil compaction from tractor journeys. Great progress has been made in the past 25 years in our understanding of the molecular basis of plant disease resistance mechanisms, and of how pathogens circumvent them. These insights can inform more sophisticated approaches to elevating disease resistance in crops that help us tip the evolutionary balance in favour of the crop and away from the pathogen. We illustrate this theme with an account of a genetically modified (GM) blight-resistant potato trial in Norwich, using the Rpi-vnt1.1 gene isolated from a wild relative of potato, Solanum venturii , and introduced by GM methods into the potato variety Desiree.

scholarly journals Mid-infrared supercontinuum generation in chalcogenide glass fibers: a brief review

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yingying Wang ◽  
Shixun Dai
Keyword(s):  
Recent Progress ◽  
Glass Fibers ◽  
Optical Nonlinearity ◽  
Mid Infrared ◽  
Silica Glasses ◽  
The Past ◽  
Great Progress ◽  
Potential Applications ◽  
Soft Glasses ◽  
Made In

AbstractChalcogenide (ChG) glasses have the characteristics of a wide transparency window (over 20 μm) and high optical nonlinearity (up to 103 times greater than that of silica glasses), exhibiting great advantages over silica and other soft glasses in optical property at mid-infrared (MIR) wavelength range. These make them excellent candidates for MIR supercontinuum (SC) generation. Over the past decades, great progress has been made in MIR SC generation based on ChG fibers in terms of spectral extension and output power improvement. In this paper, we introduce briefly the properties of ChG glasses and fibers including transmission, nonlinearity, and dispersion, etc. Recent progress in MIR SC generation based on ChG fibers is reviewed from the perspective of pump schemes. We also present novel ChG fibers such as As-free, Te-based, and chalcohalide fibers, which have been explored and employed as nonlinear fibers to achieve broadband SC generation. Moreover, the potential applications of MIR SC sources based on ChG fibers are discussed.

scholarly journals Thermal Cloak: Theory, Experiment and Application

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7835
Author(s):  
Xiuli Yue ◽  
Junyi Nangong ◽  
Peiyan Chen ◽  
Tiancheng Han
Keyword(s):  
Heat Transfer ◽  
Thermal Conduction ◽  
Transformation Optics ◽  
Future Directions ◽  
The Past ◽  
Great Progress ◽  
Potential Applications ◽  
Invisibility Cloaks ◽  
Theory And Experiment ◽  
Made In

In the past two decades, owing to the development of metamaterials and the theoretical tools of transformation optics and the scattering cancellation method, a plethora of unprecedented functional devices, especially invisibility cloaks, have been experimentally demonstrated in various fields, e.g., electromagnetics, acoustics, and thermodynamics. Since the first thermal cloak was theoretically reported in 2008 and experimentally demonstrated in 2012, great progress has been made in both theory and experiment. In this review, we report the recent advances in thermal cloaks, including the theoretical designs, experimental realizations, and potential applications. The three areas are classified according to the different mechanisms of heat transfer, namely, thermal conduction, thermal convection, and thermal radiation. We also provide an outlook toward the challenges and future directions in this fascinating area.

scholarly journals THE COMPOSITION OF PLANETARY ATMOSPHERES

1981 ◽  
Vol 96 ◽  
pp. 1-33
Author(s):  
Th. Encrenaz ◽  
M. Combes
Keyword(s):  
Planetary Atmospheres ◽  
Space Astronomy ◽  
The Past ◽  
Great Progress ◽  
Infrared Techniques ◽  
Made In

During the past 10 years, great progress has been made in our knowledge of the planetary atmospheres, mainly due to the recent development of infrared techniques and space astronomy.

EXPERIMENTAL OVERVIEW AND CHALLENGE IN STRANGENESS NUCLEAR PHYSICS — STRANGENESS IN THE PAST AND COMING DECADES

2010 ◽  
Vol 19 (12) ◽  
pp. 2314-2325
Author(s):  
Ken'ichi Imai
Keyword(s):  
Binding Energy ◽  
Hyperfine Structure ◽  
Nuclear Physics ◽  
Weak Decay ◽  
Mesonic Decay ◽  
The Past ◽  
Great Progress ◽  
The Future ◽  
Made In

A great progress has been made in strangeness nuclear physics in the past decade. Examples are; 1) The "hyperfine" structure of hypernuclei were measured with the Hyperball, and ΛN spin dependent interactions in p -shell hypernuclei were determined. 2) The "complete measurements" of the weak decay of hypernuclei were made and the np ratio puzzle in the non-mesonic decay was solved. 3) The discovery of a clean event of "Lambpha" and determination of its binding energy concluded that the Λ-Λ interaction is weak attractive. However, we still have important questions to be answered in this field, especially in relation with QCD and nuclear physics. For the future strangeness nuclear physics, we have and will have facilities such as JLab, SPring-8, Daphne, J-PARC, FAIR. We discuss experimental challenges in the strangeness nuclear physics and related fields in the next decade.

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