487 research outputs found
Dynamics of the Quiet Solar Chromosphere
The solar chromosphere has never been static although it
was often modeled so.Even the quiet-sun internetwork chromosphere
has become thoroughly dynamic with the acoustic shock interpretation
of the Ca II K 2V grains. We concentrate on the latter in this brief review.
Recent analysis of ASP data confirms that their excitation is more likely
set acoustically than magnetically.TRACE imagery permits seeing-free
studies of their occurrence patterns
Cosmic distance-duality as probe of exotic physics and acceleration
In cosmology, distances based on standard candles (e.g. supernovae) and
standard rulers (e.g. baryon oscillations) agree as long as three conditions
are met: (1) photon number is conserved, (2) gravity is described by a metric
theory with (3) photons travelling on unique null geodesics. This is the
content of distance-duality (the reciprocity relation) which can be violated by
exotic physics. Here we analyse the implications of the latest cosmological
data sets for distance-duality. While broadly in agreement and confirming
acceleration we find a 2-sigma violation caused by excess brightening of SN-Ia
at z > 0.5, perhaps due to lensing magnification bias. This brightening has
been interpreted as evidence for a late-time transition in the dark energy but
because it is not seen in the d_A data we argue against such an interpretation.
Our results do, however, rule out significant SN-Ia evolution and extinction:
the "replenishing" grey-dust model with no cosmic acceleration is excluded at
more than 4-sigma despite this being the best-fit to SN-Ia data alone, thereby
illustrating the power of distance-duality even with current data sets.Comment: 6 pages, 4 colour figures. Version accepted as a Rapid Communication
in PR
Distribution of reflection eigenvalues in many-channel chaotic cavities with absorption
The reflection matrix R=S^{\dagger}S, with S being the scattering matrix,
differs from the unit one, when absorption is finite. Using the random matrix
approach, we calculate analytically the distribution function of its
eigenvalues in the limit of a large number of propagating modes in the leads
attached to a chaotic cavity. The obtained result is independent on the
presence of time-reversal symmetry in the system, being valid at finite
absorption and arbitrary openness of the system. The particular cases of
perfectly and weakly open cavities are considered in detail. An application of
our results to the problem of thermal emission from random media is briefly
discussed.Comment: 4 pages, 2 figures; (Ref.[5b] added, appropriate modification in
text
Disorder and relaxation mode in the lattice dynamics of PbMgNbO relaxor ferroelectric
The low-energy part of vibration spectrum in PbMgNbO
relaxor ferroelectric was studied by inelastic neutron scattering. We observed
the coexistence of a resolution-limited central peak with strong quasielastic
scattering. The line-width of the quasielastic component follows a
dependence. We find that is temperature-dependent.
The relaxation time follows the Arrhenius law well. The presence of a
relaxation mode associated with quasi-elastic scattering in PMN indicates that
order-disorder behaviour plays an important r\^ole in the dynamics of diffuse
phase transitions
Histochemical Investigation of the Modal Specificity of Taste
The taste mechanism was investigated in a primate (Macaca mulatta). Based on the hypothesis that intracellular enzymes contribute to the transduction of tastes to electric impulses by taste cells, a histochemical survey of the activity of several enzymes was made on taste buds from regions of the mouth associated with sweet, salt, sour, and bitter tastes. Considerable differences were noted among the modalities, which confirmed the hypothesis. An exclusively bitter enzyme was identified.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66599/2/10.1177_00220345720510050601.pd
Synchronization of perturbed non-linear Hamiltonians
We propose a new method based on Lie transformations for simplifying perturbed Hamiltonians in one degree of freedom. The method is most useful when the unperturbed part has solutions in non-elementary functions. A non-canonical Lie transformation is used to eliminate terms from the perturbation that are not of the same form as those in the main part. The system is thus transformed into a modified version of the principal part. In conjunction with a time transformation, the procedure synchronizes the motions of the perturbed system onto those of the unperturbed part.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42559/1/10569_2004_Article_BF00692993.pd
Defect-induced condensation and central peak at elastic phase transitions
Static and dynamical properties of elastic phase transitions under the
influence of short--range defects, which locally increase the transition
temperature, are investigated. Our approach is based on a Ginzburg--Landau
theory for three--dimensional crystals with one--, two-- or three--dimensional
soft sectors, respectively. Systems with a finite concentration of
quenched, randomly placed defects display a phase transition at a temperature
, which can be considerably above the transition temperature
of the pure system. The phonon correlation function is calculated in
single--site approximation. For a dynamical central peak
appears; upon approaching , its height diverges and its width
vanishes. Using an appropriate self--consistent method, we calculate the
spatially inhomogeneous order parameter, the free energy and the specific heat,
as well as the dynamical correlation function in the ordered phase. The
dynamical central peak disappears again as the temperatur is lowered below
. The inhomogeneous order parameter causes a static central
peak in the scattering cross section, with a finite width depending on the
orientation of the external wave vector relative to the soft sector.
The jump in the specific heat at the transition temperatur of the pure system
is smeared out by the influence of the defects, leading to a distinct maximum
instead. In addition, there emerges a tiny discontinuity of the specific heat
at . We also discuss the range of validity of the mean--field
approach, and provide a more realistic estimate for the transition temperature.Comment: 11 pages, 11 ps-figures, to appear in PR
Tributes to Family Law Scholars Who Helped Us Find Our Path
At some point after the virus struck, I had the idea that it would be appropriate and interesting to ask a number of experienced family law teachers to write a tribute about a more senior family law scholar whose work inspired them when they were beginning their careers. I mentioned this idea to some other long-term members of the professoriate, and they agreed that this could be a good project.
So I reached out to some colleagues and asked them to participate. Many agreed to join the team. Some suggested other potential contributors, and some of these suggested faculty members also agreed to submit a tribute.
The authors have written about a diverse group of distinguished scholars in the area of family law. We have included 12 scholars who have contributed substantially to the field, and they have also influenced those who have written about them here. The honored scholars and the tribute authors are as follows (organized alphabetically by the honoree): Homer H. Clark Jr. (1918-2015), by Ann Laquer Estin Cooper Davis, by Melissa MurrayPeggy Mary Ann Glendon, by June Carbone Herma Hill Kay (1934-2017), by Barbara A. Atwood Robert Levy, by Paul M. Kurtz Marygold (Margo) Shire Melli (1926-2018), by J. Thomas Oldham & Bruce M. Smyth Martha Minow, by Brian H. Bix Robert Mnookin, by Elizabeth S. Scott Twila Perry, by R.A. Lenhardt Dorothy E. Roberts, by Jessica Dixon Weaver Carol Sanger, by Solangel Maldonado Barbara Bennett Woodhouse, by Sacha M. Coupet
Each colleague who participated in this project chose the scholar whose work he or she would celebrate. So, the list of those honored here is subjective and, to a certain extent, serendipitous. This Article is part of a Family Law Quarterly issue that also honors other pioneering contributors to the family law field. We hope to make this a continuing project and to have future opportunities to recognize the many scholars who have had a profound impact on their students – and on all of us – in addition to having an important impact on the development of the law. I trust the reader will find these tributes of interest
Thermodynamic Description of the Relaxation of Two-Dimensional Euler Turbulence Using Tsallis Statistics
Euler turbulence has been experimentally observed to relax to a
metaequilibrium state that does not maximize the Boltzmann entropy, but rather
seems to minimize enstrophy. We show that a recent generalization of
thermodynamics and statistics due to Tsallis is capable of explaining this
phenomenon in a natural way. The maximization of the generalized entropy
for this system leads to precisely the same profiles predicted by the
Restricted Minimum Enstrophy theory of Huang and Driscoll. This makes possible
the construction of a comprehensive thermodynamic description of Euler
turbulence.Comment: 15 pages, RevTe
Primordialists and Constructionists: a typology of theories of religion
This article adopts categories from nationalism theory to classify theories of religion. Primordialist explanations are grounded in evolutionary psychology and emphasize the innate human demand for religion. Primordialists predict that religion does not decline in the modern era but will endure in perpetuity. Constructionist theories argue that religious demand is a human construct. Modernity initially energizes religion, but subsequently undermines it. Unpacking these ideal types is necessary in order to describe actual theorists of religion. Three distinctions within primordialism and constructionism are relevant. Namely those distinguishing: a) materialist from symbolist forms of constructionism; b) theories of origins from those pertaining to the reproduction of religion; and c) within reproduction, between theories of religious persistence and secularization. This typology helps to make sense of theories of religion by classifying them on the basis of their causal mechanisms, chronology and effects. In so doing, it opens up new sightlines for theory and research
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