4,451 research outputs found
A note on the moving hyperplane method
We give more precision on the regularity of the domain that is needed to have
the monotonicity and symmetry results recently proved by Damascelli and
Pacella, result concerning p-Laplace equations. For this purpose, we study the
continuity and semicontinuity of some parameters linked with the moving
hyperplane method.Comment: 4 pages, 2 figure
Structure and magnetic properties of nanocrystalline PrCo3
The structure and magnetic properties of nanocrystalline PrCo prepared by
high-energy milling technique have been investigated by means of X-ray
diffraction using the Rietveld method coupled to Curie temperature and magnetic
measurements. The as-milled samples were subsequently annealed in temperature
range from 750 to 1050 {\deg}C for 30 min to optimize the extrinsic properties.
From x-ray studies of magnetic aligned samples, the magnetic anisotropy of this
compounds is found uniaxial. The Curie temperature is 349 {\deg}K and no
saturation reached at room temperature for applied field of 90 kOe. The
coercive field of 55 kOe and 12 kOe measured at 10 and 293 K respectively is
obtained after annealing at 750 {\deg}C for 30 min suggests that
nanocrystalline PrCo are interesting candidates in the field of permanent
magnets. We have completed this experimental study by simulations in the
micromagnetic framework in order to get a qualitative picture of the
microstructure effect on the macroscopic magnetization curve. From this simple
model calculation, we can suggest that the after annealing the system behaves
as magnetically hard crystallites embedded in a weakly magnetized amorphous
matrix. PACS : 75.50.Bb, 75.50.Tt, 76.80.+yComment: Published in Journal of Applied Physics, 107, 083916 (2010). To be
found at: http://jap.aip.or
The nature of turbulence in OMC1 at the star forming scale: observations and simulations
Aim: To study turbulence in the Orion Molecular Cloud (OMC1) by comparing
observed and simulated characteristics of the gas motions.
Method: Using a dataset of vibrationally excited H2 emission in OMC1
containing radial velocity and brightness which covers scales from 70AU to
30000AU, we present the transversal structure functions and the scaling of the
structure functions with their order. These are compared with the predictions
of two-dimensional projections of simulations of supersonic hydrodynamic
turbulence.
Results: The structure functions of OMC1 are not well represented by power
laws, but show clear deviations below 2000AU. However, using the technique of
extended self-similarity, power laws are recovered at scales down to 160AU. The
scaling of the higher order structure functions with order deviates from the
standard scaling for supersonic turbulence. This is explained as a selection
effect of preferentially observing the shocked part of the gas and the scaling
can be reproduced using line-of-sight integrated velocity data from subsets of
supersonic turbulence simulations. These subsets select regions of strong flow
convergence and high density associated with shock structure. Deviations of the
structure functions in OMC1 from power laws cannot however be reproduced in
simulations and remains an outstanding issue.Comment: 12 pages, 8 figures, accepted A&A. Revised in response to referee.
For higher resolution, see http://www.astro.phys.au.dk/~maikeng/sim_paper
White Privilege and its Influence on the College Campus
The article explores the topic of White privilege from the author’s perspective as a White, Catholic, middle-class, rural Southern Vermont woman. White privilege affects every aspect of the college campus, from academics to residence life. Within the context of this understanding, White student affairs professionals can better understand the reality of White privilege, including the loss to Whites that results from its prevalence in society and on our campuses, and work to combat racism more successfully
Who Confronts Sexual Prejudice? How Gender and Ideologies are Related to Heterosexual Allies Challenging Hate Speech
Sexual prejudice and discrimination are extremely prevalent throughout society and previous research suggests that there are a multitude of negative consequences associated with being the target of this prejudice. One way of reducing prejudice is by confronting the perpetrator; however the majority of previous research examining confrontation has focused on the target\u27s response to racism or sexism. The current study utilized a 10-condition experimental design in order to examine how the gender of the perpetrator, target, and non-target witness of heterosexist prejudice affected the witness\u27 responses. Attitudinal variables and past allied behaviors were also examined in order to determine if they predicted confrontation behavior. A sample of 298 (134 men, and 164 women) undergraduate college students participated in the current study by watching one of 4 videos in which a male or female perpetrator approaches them and makes a heterosexist comment about a lesbian woman or gay man and then answering questions about how they would respond if they were in that situation. They also completed a number of surveys about their attitudes and past behavior. Results suggest that gender of the participant, perpetrator, and target all play a significant role in responses to heterosexist hate speech. Furthermore, attitudes toward gay men, allophilia, and number of friends who identify as gay or lesbian were all significant unique predictors of confrontation responses. Implications for reduction of prejudice and future research are discussed
Heterosexual Allies\u27 Confrontation of Sexual Prejudice: the Effect of Gender, Attitudes, and Past Allied Behavior
Confrontation of prejudice is one method that has been demonstrated to reduce future discrimination on behalf of perpetrators and non-target witnesses in the future. The current study sought to 1) determine whether the gender of the perpetrator, target, or witness of heterosexist prejudice affects witness’s reactions to prejudice, including confrontation, 2) understand if other factors including participants’ attitudes about society, gender roles, and gay men and lesbian women, as well as their general level of assertiveness and previous allied behaviors were predictive of confrontation behavior and 3) examine participant’s satisfaction with their responses and anticipated future responses in relation to their behavioral responses and attitudes. A 10-condition (2x2x2, 2 controls) live experimental design was utilized to examine the participants’ responses to an overtly heterosexist comment. Specifically, participants were exposed to a person (man or woman) making heterosexist comments about either a gay man or lesbian woman and their verbal and nonverbal behavioral responses were recorded and coded. Participants also completed measures about their attitudes, personality, and previous allied behaviors. Results suggest about 25% of the sample verbally confronted the perpetrator and 25% verbally agreed. The gender of the target, non-target witness (participant), and especially the gender of the perpetrator appear to affect witnesses’ responses to prejudice, including confrontation. Additionally, both attitudinal variables, including attitudes toward gay men and personal support, and previous allied behaviors, including the LGASJC action subscale and personal relationships with gay and lesbian individuals, predicted confrontation; however, gender of the perpetrator still significantly and uniquely predicted confrontation even when accounting for these variables. Overall, individuals who confronted reported being more satisfied with their responses than those who did not and anticipated engaging in confrontation again in the future
Magnetic and structural properties of nanocrystalline PrCo
The structure and magnetic properties of nanocrystalline PrCo obtained
from high energy milling technique are investigated by X-ray diffraction, Curie
temperature determination and magnetic properties measurements are reported.
The as-milled samples have been annealed in a temperature range of 1023 K to
1273 K for 30 mn to optimize the extrinsic properties. The Curie temperature is
349\,K and coercive fields of 55\,kOe at 10\,K and 12\,kOe at 293\,K are
obtained on the samples annealed at 1023\,K. A simulation of the magnetic
properties in the framework of micromagnetism has been performed in order to
investigate the influence of the nanoscale structure. A composite model with
hard crystallites embedded in an amorphous matrix, corresponding to the
as-milled material, leads to satisfying agreement with the experimental
magnetization curve. [ K. Younsi, V. Russier and L. Bessais, J. Appl. Phys.
{\bf 107}, 083916 (2010)]. The microscopic scale will also be considered from
DFT based calculations of the electronic structure of Co compounds,
where = (Y, Pr) and = 2,3 and 5.Comment: To be published in J. Phys.: Conference Series in the JEMS 2010
special issue. To be found once published at
http://iopscience.iop.org/1742-659
Interplanetary boundary layers at 1 AU
The structure and nature of discontinuities in the interplanetary magnetic field at 1 AU in the period March 18, 1971 to April 9, 1971, is determined by using high-resolution magnetic field measurements from Explorer 34. The discontinuities that were selected for this analysis occurred under a variety of interplanetary conditions at an average rate of 0.5/hr. This set does not include all discontinuities that were present, but the sample is large and it is probably representative. Both tangential and rotational discontinuities were identified, the ratio of TD's to RD's being approximately 3 to 1. Tangential discontinuities were observed every day, even among Alfvenic fluctuations. The structure of most of the boundary layers was simple and ordered, i.e., the magnetic field usually changed smoothly and monotonically from one side of the boundary layer to the other
DC-conductivity of a suspension of insulating particles with internal rotation
We analyse the consequences of Quincke rotation on the conductivity of a
suspension. Quincke rotation refers to the spontaneous rotation of insulating
particles dispersed in a slightly conducting liquid and subject to a high DC
electric field: above a critical field, each particle rotates continuously
around itself with an axis pointing in any direction perpendicular to the DC
field. When the suspension is subject to an electric field lower than the
threshold one, the presence of insulating particles in the host liquid
decreases the bulk conductivity since the particles form obstacles to ion
migration. But for electric fields higher than the critical one, the particles
rotate and facilitate ion migration: the effective conductivity of the
suspension is increased. We provide a theoretical analysis of the impact of
Quincke rotation on the apparent conductivity of a suspension and we present
experimental results obtained with a suspension of PMMA particles dispersed in
weakly conducting liquids
Observations of spatial and velocity structure in the Orion Molecular Cloud
Observations are reported of H2 IR emission in the S(1) v=1-0 line at 2.121
microns in the Orion Molecular Cloud, OMC1, using the GriF instrument on the
Canada-France-Hawaii Telescope. GriF is a combination of adaptive optics and
Fabry-Perot interferometry, yielding a spatial resolution of 0.15" to 0.18" and
a velocity discrimination as high as 1 km/s. Thanks to the high spatial and
velocity resolution of the GriF data, 193 bright H2 emission regions can be
identified in OMC1. The general characteristics of these features are described
in terms of radial velocities, brightness and spatial displacement of maxima of
velocity and brightness, the latter to yield the orientation of flows in the
plane of the sky. Strong spatial correlation between velocity and bright H2
emission is found and serves to identify many features as shocks. Important
results are: (i) velocities of the excited gas illustrate the presence of a
zone to the south of BN-IRc2 and Peak 1, and the west of Peak 2, where there is
a powerful blue-shifted outflow with an average velocity of -18 km/s. This is
shown to be the NIR counterpart of an outflow identified in the radio from
source I, a very young O-star. (ii) There is a band of weak velocity features
(<5 km/s) in Peak 1 which may share a common origin through an explosive event,
in the BN-IRc2 region, with the fast-moving fingers (or bullets) to the NW of
OMC1. (iii) A proportion of the flows are likely to represent sites of low mass
star formation and several regions show multiple outflows, probably indicative
of multiple star formation within OMC1. The high spatial and velocity
resolution of the GriF data show these and other features in more detail than
has previously been possible.Comment: 27 pages, 19 figures, submitted to A&A Version 2: Several additions,
including a section on protostellar candidates in OMC1, have been made based
on the referee's suggestions v3: corrected typograph
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