Individual and Collective Aspects of the Microfield Distribution

1971 ◽  
Vol 26 (8) ◽  
pp. 1360-1365
Author(s):  
Günter H. ◽  
Klaus G. Fischer
Keyword(s):  
High Frequency ◽  
Individual Component ◽  
Plasma Parameter ◽  
Electron Gas ◽  
Critical Density ◽  
Collective Modes ◽  
Exact Formulation ◽  
Collective Phenomena ◽  
Frequency Profile ◽  
The Individual

Starting from the exact formulation of the electric microfield distribution in an electron gas the question is investigated of whether collective phenomena are correctly included in previous calculations. Application of Böhm and Pines' procedure yields a separable expression for the total microfield distribution: the collective component is represented by a Gaussian distribution, the individual component is similar to the high-frequency profile of Baranger and Mozer. Both components vary with the cut-off parameter of the spectrum of the collective modes. For realistic values of this cut-off parameter the total distribution may differ from the high-frequency profile as much as ten per cent for systems close to the critical density. With increasing plasma parameter Λ the distribution approaches that of Holtsmark

scholarly journals Interplay between collective modes in hybrid electron-gas–superconductor structures

2020 ◽  
Vol 101 (16) ◽  
Author(s):  
M. V. Boev ◽  
I. G. Savenko ◽  
V. M. Kovalev
Keyword(s):  
Electron Gas ◽  
Collective Modes

scholarly journals From an ethnography of the everyday to writing echoes of suffering

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Richard Rechtman
Keyword(s):  
Everyday Life ◽  
Racial Group ◽  
Collective Modes ◽  
The Third ◽  
The Everyday ◽  
Major Shift ◽  
The Individual

Veena Das has introduced a major shift in our contemporary conception of ethnography. While she brings forward a new way of looking at everyday life, which is already a major achievement, she also offers a conceptual resolution to a classical unresolved opposition between the individual and the collective, and between idiosyncratic psychology (subjectivity) and collective modes of thinking, through a challenging debate on what makes one a member of a group and yet radically distinct from all others. The ethnography in her book Affliction stands on three major pillars: The first is the ethnographer’s subjective position in the field regarding the issues of lives, testimony, and research. The second is the neighborhood as the site of fieldwork, with all of its heterogeneity, rather than the group, such as an ethnic or racial group or one cohering around another criterion of belonging. The third and final pillar is the focus on the ordinary through ethnography of the everyday. I then illustrate Veena Das’s perspective on subjectivity with my own fieldwork with survivors of the Cambodian genocide.

scholarly journals The Composition of Cigarette Smoke. An Historical Perspective of Several Polycyclic Aromatic Hydrocarbons

2009 ◽  
Vol 23 (6) ◽  
pp. 384-410 ◽  
Author(s):  
A Rodgman ◽  
LC Cook
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Melting Point ◽  
Cigarette Smoke ◽  
Aromatic Hydrocarbons ◽  
Tobacco Smoke ◽  
Individual Component ◽  
Complex Mixtures ◽  
Polycyclic Aromatic ◽  
The Individual ◽  
Cigarette Mainstream Smoke

AbstractBecause of the significant advancements in fractionation, analytical, and characterization technologies since the early 1960s, hundreds of components of complex mixtures have been accurately characterized without the necessity of actually isolating the individual component. This has been particularly true in the case of the complex mixtures tobacco and tobacco smoke. Herein, an historical account of a mid-1950 situation concerning polycyclic aromatic hydrocarbons (PAHs) in cigarette smoke is presented. While the number of PAHs identified in tobacco smoke has escalated from the initial PAH, azulene, identified in 1947 to almost 100 PAHs identified by late 1963 to more than 500 PAHs identified by the late 1970s, the number of PAHs isolated individually and characterized by several of the so-called classical chemical means (melting point, mixture melting point, derivative preparation and properties) in the mid-1950s and since is relatively few, 14 in all. They were among 44 PAHs identified in cigarette mainstream smoke and included the following PAHs ranging from bicyclic to pentacyclic: Acenaphthylene, 1,2-dihydroacenaphthylene, anthracene, benz[a]anthracene, benzo[a]pyrene, chrysene, dibenz[a, h]anthracene, fluoranthene, 9H-fluorene, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, phenanthrene, and pyrene. One of them, benzo[a]pyrene, was similarly characterized in another study in 1959 by Hoffmann.

scholarly journals Vocabulary size and use: Lexical richness in L2 written production

2020 ◽  
Author(s):  
B Laufer ◽  
Paul Nation
Keyword(s):  
High Frequency ◽  
Close Correspondence ◽  
Vocabulary Size ◽  
Reliable Measure ◽  
Lexical Frequency ◽  
Frequency Profile ◽  
Oxford University ◽  
Lexical Richness ◽  
Vocabulary Growth ◽  
General Service

This article shows that if there is some control over genre then there will be a close correspondence between the vocabulary size of intermediate learners as reflected in their writing and a more direct measure of vocabulary size The study proposes a new measure of lexical richness, the Lexical Frequency Profile, which looks at the proportion of high frequency general service and academic words in learners' writing The study shows that it is possible to obtain a reliable measure of lexical richness which is stable across two pieces of writing by the same learners It also discriminates between learners of different proficiency levels For learners of English as a second language, the Lexical Frequency Profile is seen as being a measure of how vocabulary size is reflected in use In this study, it was found that the Lexical Frequency Profile correlates well with an independent measure of vocabulary size This reliable and valid measure of lexical richness in writing will be useful for determining the factors that affect judgements of quality in writing and will be useful for examining how vocabulary growth is related to vocabulary use. © 1995 Oxford University Press.

scholarly journals Vocabulary size and use: Lexical richness in L2 written production

2020 ◽  
Author(s):  
B Laufer ◽  
Paul Nation
Keyword(s):  
High Frequency ◽  
Close Correspondence ◽  
Vocabulary Size ◽  
Reliable Measure ◽  
Lexical Frequency ◽  
Frequency Profile ◽  
Oxford University ◽  
Lexical Richness ◽  
Vocabulary Growth ◽  
General Service

This article shows that if there is some control over genre then there will be a close correspondence between the vocabulary size of intermediate learners as reflected in their writing and a more direct measure of vocabulary size The study proposes a new measure of lexical richness, the Lexical Frequency Profile, which looks at the proportion of high frequency general service and academic words in learners' writing The study shows that it is possible to obtain a reliable measure of lexical richness which is stable across two pieces of writing by the same learners It also discriminates between learners of different proficiency levels For learners of English as a second language, the Lexical Frequency Profile is seen as being a measure of how vocabulary size is reflected in use In this study, it was found that the Lexical Frequency Profile correlates well with an independent measure of vocabulary size This reliable and valid measure of lexical richness in writing will be useful for determining the factors that affect judgements of quality in writing and will be useful for examining how vocabulary growth is related to vocabulary use. © 1995 Oxford University Press.

scholarly journals High-frequency profile in adolescents and its relationship with the use of personal stereo devices

2016 ◽  
Vol 92 (2) ◽  
pp. 206-211 ◽  
Author(s):  
Renata Almeida Araújo Silvestre ◽  
Ângela Ribas ◽  
Rogério Hammerschmidt ◽  
Adriana Bender Moreira de Lacerda
Keyword(s):  
High Frequency ◽  
Frequency Profile

Abstract P502: Abnormal Myocyte Calcium Dynamics And The Resultant Contraction Band Formation Of The Rat Heart Under Irreversible Injury By Membrane Permeabilization

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Yuma Morishita ◽  
Shoko Tamura ◽  
Kentaro Mochizuki ◽  
Yoshinori Harada ◽  
Hideo Tanaka
Keyword(s):  
Fluorescence Intensity ◽  
High Frequency ◽  
Time Course ◽  
Morphological Changes ◽  
Confocal Imaging ◽  
Band Formation ◽  
Contraction Band Necrosis ◽  
Scanning Confocal Microscopy ◽  
The Individual ◽  
Contraction Band

Ca 2+ overload is a cardinal feature of cardiomyocyte injury, and its progression to irreversible state leads to cell death. However, unknowns are the precise spatiotemporal changes in the myocyte Ca 2+ dynamics and the relevant cell morphology of irreversibly injured hearts. On the hypothesis that myocytes exhibit high-frequency Ca 2+ waves and contraction band necrosis in saponin-permeabilized injured heart, we observed changes in the Ca 2+ dynamics and the relevant morphological changes in the subepicardial myocardium of the Fluo4-loaded rat hearts (n = 14) by rapid-scanning confocal microscopy (100 frames/s) under Langendorff perfusion with 0.3 mM Ca 2+ -Tyrode solution including 0.4 % saponin at 30°C. Also performed was confocal imaging of tetramethylrhodamine methyl ester (TMRM) fluorescence of the myocardium. Under quasi-quiescence of the heart after dissection of the SA node, individual myocytes barely exhibited spontaneous Ca 2+ waves, whereas after commencement of saponin perfusion high-frequency (118 ± 9.7 /min/cell, mean ± SEM) Ca 2+ waves (hereafter, “agonal waves”) emerged within 1 min, showing asynchronous, oscillatory contractions in the individual myocytes with a V prop of 124 ± 2.5 μm/s (n = 60). Subsequently, the waves gradually decreased in frequency with concomitant slowing of its decay time course, and eventually, disappeared in 6 min; myocytes exhibited high, static Fluo4-fluorescence intensity. Along with the progression of Ca 2+ overload by saponin, the TMRM fluorescence intensity was discretely lost in individual myocytes. The myocytes showing the agonal waves exhibited contraction bands, i.e., band-like aggregations of the actin fibers. Under mechanical arrest of the heart by 2,3-butanedione monoxime (20 mM), saponin still induced the agonal waves with a frequency of 253 ± 10.6 /cell/min and V prop of 118 ± 2.1 μm/s (n = 60); however, contraction bands were barely seen.In conclusion, irreversible myocyte injury by saponin provoked agonal Ca 2+ waves and oscillatory contractions indicating progressive Ca 2+ overload and the following mitochondrial damage, which may provide deeper insights into understanding the mechanism of contraction band necrosis.

Individual entrenchment vs. community-wide conventionalization of contact features in L2 Basque speakers’ individual styles

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Hanna Lantto
Keyword(s):  
Individual Variation ◽  
High Frequency ◽  
Personal Experience ◽  
Language Contact ◽  
Language Attitudes ◽  
Linguistic Variation ◽  
Speech Styles ◽  
Speech Patterns ◽  
Base Language ◽  
The Individual

AbstractThis article examines individual variation of contact features in the speech patterns of four L2 Basque speakers. The individual styles are examined through the concepts of individual entrenchment and community-wide conventionalization to bridge the gap between linguistic variation and change at the individual and social levels. All the informants speak Spanish as their L1. They have acquired Basque in classroom contexts, and they belong to the same macrosociolinguistic categories. Yet their patterns of using the language contact between standard Basque, vernacular Basque dialects and Spanish as a resource in creating individual speech styles differ considerably, reflecting their language attitudes and their personal experience. Nevertheless, there are conventionalized patterns that emerge out of this diversity: All speakers use the standard Basque as the base language, and none of them adopts of vernacular variety as a whole. The Spanish resources seem to be used mainly for pragmatic and stylistic functions, whereas the features of vernacular Basque that the speakers have adopted as part of their individual styles are high frequency elements of core grammar.

scholarly journals The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 469-474 ◽  
Author(s):  
S W Leavitt ◽  
Austin Long
Keyword(s):  
High Frequency ◽  
Ice Core ◽  
Ring Width ◽  
Ice Cores ◽  
The Other ◽  
Core Data ◽  
Single Tree ◽  
Pinyon Pine ◽  
The Individual ◽  
First Time

We have developed a master δ13C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt & Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt & Long, 1985). Regressions of first differences of ring-width indices and δ13C values from each site were used to “correct” individual δ13C chronologies for climate effects which appear primarily related to high-frequency δ13C fluctuations, many of which are common among sites. These climate-corrected chronologies were normalized as deviations from their respective 1800–1849 δ13C means, and these normalized chronologies were averaged into the master. The overall δ13C drop from 1600 to the present is ca 1.2–1.4, consistent with recent ice-core data showing a drop of 1.14 ± 0.15% from 1740 to present (Friedli et al, 1986). However, the δ13C decline in the late 19th and early 20th centuries is greater in the pinyon chronology than that of the ice cores, thus supporting a greater biospheric CO2 input to the atmosphere than that indicated in the ice-core data.

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