scholarly journals Effects of wind clumping on colliding winds

1995 ◽  
Vol 163 ◽  
pp. 411-415
Author(s):  
Sébastien Lépine
Keyword(s):  
Filling Factor ◽  
Power Laws ◽  
Compressible Turbulence ◽  
Wind Component ◽  
Wind Model ◽  
Two Factors ◽  
The Difference ◽  
Colliding Winds ◽  
Hierarchy Of Structures ◽  
Emission Line Profile

Recent studies of variable Wolf-Rayet emission lines reveal a hierarchy of structures, characterized by power laws analogous to what is expected from supersonic compressible turbulence. The collision of inhomogeneous winds can be very different from the case of smooth winds. The difference will mainly depend on two factors: (i) the relative importance of the inhomogeneous compared to the homogeneous component; and (ii) the characteristic filling factor of the inhomogeneous component. Using relations derived from observations of variable line structures (“blobs”), it can be deduced that the flux emitted by the inhomogeneous part of the wind of a WR star is dominated by its smallest structures. This implies that a significant fraction of the underlying emission line profile could be produced by small, undetectable inhomogeneities. It can also be deduced that the volume spanned by the inhomogeneities is dominated by the largest structures. This in turn implies that the filling factor should be low, or that we are dealing with a fractal-like hierarchy. It is suggested that the wind is composed of dense structures separated by large “voids” which may actually be filled by a homogeneous wind component. The interacting zone of two inhomogeneous colliding winds should thus be much more extended in space than for a smooth-wind model, because the dense, inhomogeneous structures are able to penetrate through the large “voids”.

Structuring, Motions and Shapes of Corona Emission Line Profiles

1994 ◽  
Vol 144 ◽  
pp. 421-426
Author(s):  
N. F. Tyagun
Keyword(s):  
Emission Line ◽  
Filling Factor ◽  
Direct Relationship ◽  
Coronal Plasma ◽  
Line Of Sight ◽  
Line Profiles ◽  
The Difference ◽  
Yellow Line ◽  
Red Line

AbstractThe interrelationship of half-widths and intensities for the red, green and yellow lines is considered. This is a direct relationship for the green and yellow line and an inverse one for the red line. The difference in the relationships of half-widths and intensities for different lines appears to be due to substantially dissimilar structuring and to a set of line-of-sight motions in ”hot“ and ”cold“ corona regions.When diagnosing the coronal plasma, one cannot neglect the filling factor - each line has such a factor of its own.

Slow Down You’re Moving Too Fast

2015 ◽  
Vol 27 (2) ◽  
pp. 53-63 ◽  
Author(s):  
Annie Lang ◽  
Nancy Schwartz ◽  
Sharon Mayell
Keyword(s):  
Older Adults ◽  
Cognitive Aging ◽  
Attention And Memory ◽  
Younger Adults ◽  
Media Messages ◽  
Two Factors ◽  
The Difference

The study reported here compared how younger and older adults processed the same set of media messages which were selected to vary on two factors, arousing content and valence. Results showed that older and younger adults had similar arousal responses but different patterns of attention and memory. Older adults paid more attention to all messages than did younger adults. However, this attention did not translate into greater memory. Older and younger adults had similar levels of memory for slow-paced messages, but younger adults outperformed older adults significantly as pacing increased, and the difference was larger for arousing compared with calm messages. The differences found are in line with predictions made based on the cognitive-aging literature.

scholarly journals An experimental and theoretical investigation of diffusion in a two-phase alloy

1948 ◽  
Vol 192 (1031) ◽  
pp. 575-592 ◽  
Keyword(s):  
Free Energy ◽  
Single Phase ◽  
Phase State ◽  
Theoretical Treatment ◽  
Research Association ◽  
Essential Difference ◽  
Two Phase ◽  
Two Factors ◽  
Order Of Magnitude ◽  
The Difference

The present paper describes an investigation of diffusion in the solid state. Previous experimental work has been confined to the case in which the free energy of a mixture is a minimum for the single-phase state, and diffusion decreases local differences of concentration. This may be called ‘diffusion downhill’. However, it is possible for the free energy to be a minimum for the two-phase state; diffusion may then increase differences of concentration; and so may be called ‘diffusion uphill’. Becker (1937) has proposed a simple theoretical treatment of these two types of diffusion in a binary alloy. The present paper describes an experimental test of this theory, using the unusual properties of the alloy Cu 4 FeNi 3 . This alloy is single phase above 800° C and two-phase at lower temperatures, both the phases being face-centred cubic; the essential difference between the two phases is their content of copper. On dissociating from one phase into two the alloy develops a series of intermediate structures showing striking X-ray patterns which are very sensitive to changes of structure. It was found possible to utilize these results for a quantitative study of diffusion ‘uphill’ and ‘downhill’ in the alloy. The experimental results, which can be expressed very simply, are in fair agreement with conclusions drawn from Becker’s theory. It was found that Fick’s equation, dc / dt = D d2c / dx2 , can, within the limits of error, be applied in all cases, with the modification that c denotes the difference of the measured copper concentration from its equilibrium value. The theory postulates that D is the product of two factors, of which one is D 0f the coefficient of diffusion that would be measured if the alloy were an ideal solid solution. The theory is able to calculate D/D 0 , if only in first approximation, and the experiments confirm this calculation. It was found that in most cases the speed of diffusion—‘uphill’ or ‘downhill’—has the order of magnitude of D 0 . * Now with British Electrical Research Association.

The opposite and antagonistic effects of the closely related POU family transcription factors Brn-3a and Brn-3b on the activity of a target promoter are dependent on differences in the POU domain

1994 ◽  
Vol 14 (10) ◽  
pp. 6907-6914
Author(s):  
P J Morris ◽  
T Theil ◽  
C J Ring ◽  
K A Lillycrop ◽  
T Moroy ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Promoter Activity ◽  
Group Iv ◽  
Promoter Activation ◽  
Antagonistic Effects ◽  
Pou Domain ◽  
Close Relationship ◽  
Two Factors ◽  
The Difference ◽  
Target Promoter

The Brn-3a, Brn-3b, and Brn-3c POU family transcription factors are closely related to one another and are members of the group IV subfamily of POU factors. Here we show that despite this close relationship, the factors have different effects on the activity of a target promoter: Brn-3a and Brn-3c stimulate the promoter whereas Brn-3b represses it. Moreover, Brn-3b can antagonize the stimulatory effect of Brn-3a on promoter activity and can also inhibit promoter activation by the Oct-2.1 POU factor. The difference in the transactivation activities of Brn-3a and Brn-3b is dependent upon the C-terminal region containing the POU domain of the two proteins, since exchange of this domain between the two factors converts Brn-3a into a repressor and Brn-3b into an activator.

scholarly journals Using Generalized Procrustes Analysis for Evaluation of Sensory Characteristic Data of Lamb Meat

2019 ◽  
Vol 7 (6) ◽  
pp. 840
Author(s):  
Gazel Ser
Keyword(s):  
Procrustes Analysis ◽  
Fasting Period ◽  
Multivariate Statistic ◽  
Generalized Procrustes Analysis ◽  
Alfalfa Hay ◽  
Two Factors ◽  
Total Variability ◽  
Sensory Analyses ◽  
The Difference ◽  
Meat Samples

Generalized Procrustes Analysis (GPA) is a multivariate statistic method that is used at the evaluation of sensory analyses in the food industry. GPA provides benefit in terms of decreasing the difference between the panellists and bringing the data obtained from different panellists together. In this study, the aim was to determine the effect of a pre-slaughter fasting period on sensory characteristics of lambs fed with different rations using GPA. Semi-trained panellists formed from twenty-six persons were requested for evaluation of the meat samples such as tenderness, juiciness, flavour and overall liking rated on a scale of 1(extremely dislike) to 9 (extremely good). The first two factors obtained by GPA explained 66.74% of total variability. As a result of the analysis, it was determined that 12 h and 24 h fasting of lambs fed barley supplemented with alfalfa hay were less preferable when compared to lambs fed alfalfa hay only. In addition, lambs in both groups with 48 h fasting were preferred less by the panellists. In conclusion, GPA analysis provides useful data concerning the sensitivity of each panellist in a sensory panel test.

The difference model of disability: A change in direction for vocational rehabilitation practice

2020 ◽  
Vol 26 (1) ◽  
pp. 12-17
Author(s):  
Jonathon S. Breen ◽  
Susan Forwell
Keyword(s):  
Vocational Rehabilitation ◽  
Social Forces ◽  
Job Seekers ◽  
Difference Model ◽  
Models Of Disability ◽  
The Social ◽  
Two Factors ◽  
Employment Goals ◽  
The Difference ◽  
The Individual

AbstractVocational rehabilitation provides guidance and support to individuals with disabilities entering the workforce. Employment plans include considerations of goals, the job market, and pre-existing or trainable skills on the part of job seekers. This process also includes an understanding of the social forces that affect employment goals. Current models of disability include the medical, social, and embodiment models. Each is cognitively based and assumes an element of responsibility or blame, that is, respectively, focused on the individual with a disability, the community, or a combination of these two factors. The difference model of disability offers an alternative understanding of disability by providing an affect-based framework that eliminates the premise of blame. This conceptualization of disability provides a new approach to vocational rehabilitation.

COLLECTIVE EXCITATIONS IN SEMICONDUCTOR AND GRAPHENE BILAYERS IN HIGH MAGNETIC FIELD

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2851-2855
Author(s):  
VERONIKA BISTI
Keyword(s):  
Magnetic Field ◽  
Charge Density ◽  
Ground State ◽  
Asymmetry Parameter ◽  
Filling Factor ◽  
Electron System ◽  
Collective Excitations ◽  
Graphene Layers ◽  
Space Symmetry ◽  
The Difference

The effect of space symmetry on magnetoplasmon charge density and spin-density excitations in a weakly tunnel coupled bilayer electron system at the filling factor ν = 4 is considered. The optic magnetoplasmon energy as well as the energy of intralayer magnetoexciton is not affected by space symmetry. Three other collective magnetoplasmon modes as well as three magnetoexciton modes are determined by relations between the asymmetry parameter, tunnel parameter, and the difference in energies of intralayer and interlayer magnetoexcitons. The charge-density excitations in bilayer graphene at the filling-factor ν ≪ 1 are considered. The presence of small asymmetry of graphene layers is taken into account. It is demonstarted that the magnetoplasmon energy depends on the bilayer ground state.

scholarly journals The end of the re-ionization epoch probed by Lyα emitters at z = 6.5

2006 ◽  
Vol 2 (14) ◽  
pp. 256-256
Author(s):  
Nobunari Kashikawa
Keyword(s):  
Spatial Distribution ◽  
Luminosity Function ◽  
Narrow Band ◽  
Neutral Fraction ◽  
Wind Model ◽  
Composite Spectrum ◽  
Galactic Wind ◽  
Extensive Search ◽  
The Difference ◽  
The Universe

AbstractWe report an extensive search for Lyα emitters (LAEs) at z = 6.5 in the Subaru Deep Field (SDF). We carried out spectroscopic observations with Subaru/Keck to identify LAEs at z = 6.5 that were selected by narrow-band excess at 920nm. We have identified eight new LAEs based on their significantly asymmetric Lyα emission profiles. This increases the sample of spectroscopically confirmed z = 6.5 LAEs in the SDF to 17. Based on this spectroscopic sample of 17, complemented by a photometric sample of 58 LAEs, we have derived a more accurate Lyα luminosity function (LF) of LAEs at z = 6.5, which reveals an apparent deficit at the bright end, of ∼0.75 mag fainter L*, compared with that observed at z = 5.7. The difference has 3σ significance, which is reduced to 2σ when cosmic variance is taken into account. Several LAEs with high Lyα luminosity have been actually identified by spectroscopy at z<5.7, while our LAE sample at z = 6.5 has no confirmed object having such a high Lyα luminosity. The LF of the rest UV continuum, which is not sensitive to neutral IGM, of our LAE sample has almost the same as those of LAEs at z = 5.7 and i-dropouts at z≃6, even at their bright ends. This result may imply that the reionization of the universe has not been completed at z = 6.5. The decline of the Lyα LF implies the cosmic neutral fraction xHI=0.45 based on a theoretical IGM model, although this predicted value is strongly model dependent. The spatial distribution of our LAE sample was found to be homogeneous over the field, based on three independent methods to quantify the clustering strength. The composite spectrum of our LAE sample clearly reveals an asymmetric Lyα profile with an extended red wing, which can be explained by either a galactic wind model composed of double Gaussian profiles, or by a reionization model expected from the damping wing profile. Although our result has uncertainties in LAE evolution and large cosmic variance, it can be interpreted that LAEs at z = 6.5 are at the end of the reionization epoch.

Literary vs. Technical Writing: Substitutes vs. Standards for Reality

1988 ◽  
Vol 18 (3) ◽  
pp. 241-262 ◽  
Author(s):  
Alan D. Manning
Keyword(s):  
Technical Writing ◽  
Visual Representation ◽  
Visual Medium ◽  
Line Drawings ◽  
Predominant Type ◽  
Two Factors ◽  
Literary Writing ◽  
The Difference ◽  
The Way

This article proposes a means of characterizing the difference between technical and literary writing, involving a theory of representation in which these distinct writing types are comparable to distinct types of visual representation. Any difference is only intelligible relative to a background of similarlity, but recent discussions of technical writing emphasize its similarity to literature and ignore significant differences. Distinct types of line drawings replicate the literary/technical contrast in a visual medium. This arises from two factors: 1) the way in which the drawing/text is perceived by the viewer/reader, as a substitute or as a standard; and 2) the predominant type of detail in the drawing/text, iterative or contrastive. Literature is most effective if perceived as a substitute for reality, predominated by iterative detail. Technical writing is most effective if perceived as a standard for evaluating reality, predominated by contrastive detail.

scholarly journals Learning Processes in Hierarchical Pairs Regulate Entire Gene Expression in Cells

2021 ◽  
Author(s):  
Tomoyuki Yamaguchi
Keyword(s):  
Gene Expression ◽  
Learning Process ◽  
Expression Patterns ◽  
Two Factors ◽  
Regulatory Cascades ◽  
Target Ratio ◽  
A Cell ◽  
The Difference ◽  
Genetically Determined ◽  
Entire Gene

Abstract Expression of numerous genes is precisely controlled in a cell in various contexts. While genetic and epigenetic mechanisms contribute to this regulation, how each mechanism cooperates to ensure the proper expression patterns of whole gene remains unclear. Here, I theoretically show that the repetition of simple biological processes makes appropriate whole-gene expression only if the appropriateness of current pattern is roughly detectable. A learning pair model is developed, in which two factors autonomously approach the target ratio by repeating two stochastic processes; competitive amplification with a small addition term and decay depending on the difference between the current and target ratios. Furthermore, thousands of factors are self-regulated in a hierarchical-pair architecture, in which the activation degrees competitively amplify, while transducing the activation signal, and decay at four different probabilities. Changes in whole-gene expression during human early embryogenesis and hematopoiesis are reproduced in simulation using this epigenetic learning process in a single genetically-determined hierarchical-pair architecture of gene regulatory cascades. On the background of this learning process, I propose the law of biological inertia which means that a living cell basically maintains the expression pattern while renewing the contents.

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