3,304 research outputs found
Near room-temperature colossal magnetodielectricity and multiglass properties in partially-disordered La2NiMnO6
We report magnetic, dielectric and magnetodielectric responses of pure
monoclinic bulk phase of partially-disordered La2NiMnO6, exhibiting a spectrum
of unusual properties and establish that this system intrinsically is a true
multiglass with a large magnetodielectric coupling (8-20%) over a wide range of
temperatures (150 - 300 K). Specifically, our results establish a unique way to
obtain colossal magnetodielectricity, independent of any striction effects, by
engineering the asymmetric hopping contribution to the dielectric constant via
the tuning of the relative spin orientations between neighboring magnetic ions
in a transition metal oxide system. We discuss the role of anti-site (Ni-Mn)
disorder in emergence of these unusual properties.Comment: 5 pages, 4 figures, Slightly revised version of previous article in
condmat: arXiv:1202.4319v
Defining the Observables for Quarks and Gluons Orbital Angular Momentum Distributions
We present a critical discussion of the observables that have been recently put forth to describe quarks and gluons orbital angular momentum distributions. Starting from a standard parameterization of the energy momentum tensor in QCD one can single out two forms of angular momentum, a so-called kinetic term, generally associated with the Ji decomposition, and a canonical term from the Jaffe Manohar decomposition. Orbital angular momentum has been connected to a Generalized Transverse Momentum Distribution (GTMD), for the canonical term, and to a twist three Generalized Parton Distribution for the kinetic term. We argue that while the latter appears as an azymuthal angular modulation in the longitudinal target spin asymmetry in deeply virtual Compton scattering, due to parity constraints, the GTMD associated with canonical angular momentum cannot be measured in a similar set of experiments
Corporate Hierarchies and the Size of Nations: Theory and Evidence
Corporate organization varies within a country and across countries with country size. The paper starts by establishing some facts about corporate organization based on unique data of 660 Austrian and German corporations. The larger country (Germany) has larger firms with flatter more decentral corporate hierarchies compared to the smaller country (Austria). Firms in the larger country change their organization less fast than firms in the smaller country. Over time firms have been introducing less hierarchical organizations by delegating power to lower levels of the corporation. We develop a theory which explains these facts and which links these features to the trade environment that countries and firms face. We introduce firms with internal hierarchies in a Krugman (1980) model of trade. We show that international trade and the toughness of competition in international markets induce a power struggle in firms which eventually leads to decentralized corporate hierarchies. We offer econometric evidence which is consistent with the models predictions
Seedbank and Seedling Emergence Characteristics of Weeds in Ricefield Soils of the Muda Granary Area in North-west Peninsular Malaysia
Tlie experiment was conducted in the glasshouse of UPM from March 2003 to June 2004 to determine the soil seedbank in the ricefields ot\u27Muda rice granary area in Peninsular Malaysia. Six soil cores of 5 cm in diameter and 10 cm depth were sampled from each of 24 fields. All samples from each individual field were bulked and placed in plastic trays of 38 x 25 x 10 cm. Soil was moistened as required and emergence of weed seedlings were recorded over period of one year. After one year, remaining seeds were separated, removed and identified. The total seed bank was estimated at 1136.48 million/ha of which 62.35% (708.60 million seedlings ha"1) germinated within 12 months and 37.65% (427.88 million seeds ha"1) remained ungerminated. Total of 20 taxa were recognized. Based on importance value (I.V.) the five most dominant species in terms of emerged seedling were Fimbristylis miliacea, Leplochloa chinensis, LitJwigia hyssopifolia, Cyperus difformii and C. iria. Of the remaining seeds the five dominant species with decreasing trend in ranking were F. miliacea, Scirpus lateriflonis, Monochoria vagina/is, L. hyssopifolia and L. chinensis. Ranking of total seed reserves (seedlings+ remaining seeds) were similar to emerged seedling indicating that emerged seedlings reflect the actual weed flora in the Muda area. Among the dominant species F. miliacea accounted for 58.07% of emerged seedlings, 79.31% of remaining seeds and 66.07% of total seed bank. Total seedling emergence of all species was higher in the first observation in April 2003 and cumulative seedling emergence showed no clear peaks
Inhibition of LPS-Induced Inflammatory Response of Oral Mesenchymal Stem Cells in the Presence of Galectin-3
Galectin-3 (GAL-3) is a beta-galactoside binding lectin produced by mesenchymal stem cells (MSCs) and other cell sources under inflammatory conditions. Several studies have reported that GAL-3 exerts an anti-inflammatory action, regulated by its natural ligand GAL-3 BP. In the present study, we aimed to assess the GAL-3 mediated regulation of the MSC function in an LPS-induced inflammation setting. Human gingival mesenchymal stem cells (hGMSCs) were stimulated in vitro with LPSs; the expression of TLR4, NFκB p65, MyD88 and NALP3 were assessed in the hGMSCs via immunofluorescence imaging using confocal microscopy, Western blot assay, and RT-PCR before and after the addition of GAL-3, both alone and with the addition of its inhibitors. LPSs stimulated the expression of TLR4, NFκB p65, MyD88 and NALP3 in hGMSCs, which was inhibited by GAL-3. The addition of either GAL3-BP or the antibody to GAL-3 were able to revert the GAL-3-mediated effects, restoring the expression of TLR4, NFκB p65, MyD88 and NALP3. GAL-3 induces the downregulation of the LPS-induced inflammatory program in MSCs
Pd/Cu Site Interchange and Non-Fermi-Liquid Behavior in UCu_4Pd
X-ray-absorption fine-structure measurements of the local structure in
UCu_4Pd are described which indicate a probable lattice-disorder origin for
non-Fermi-liquid behavior in this material. Short Pd-Cu distances are observed,
consistent with 24 +/- 3% of the Pd atoms occupying nominally Cu sites. A
"Kondo disorder" model, based on the effect on the local Kondo temperature T_K
of this interchange and some additional bond-length disorder, agrees
quantitatively with previous experimental susceptibility data, and therefore
also with specific heat and magnetic resonance experiments.Comment: 4 pages, 3 PostScript figures, to be published in PR
New rotation periods in the Pleiades: Interpreting activity indicators
We present results of photometric monitoring campaigns of G, K and M dwarfs
in the Pleiades carried out in 1994, 1995 and 1996. We have determined rotation
periods for 18 stars in this cluster. In this paper, we examine the validity of
using observables such as X-ray activity and amplitude of photometric
variations as indicators of angular momentum loss. We report the discovery of
cool, slow rotators with high amplitudes of variation. This contradicts
previous conclusions about the use of amplitudes as an alternate diagnostic of
the saturation of angular momentum loss. We show that the X-ray data can be
used as observational indicators of mass-dependent saturation in the angular
momentum loss proposed on theoretical grounds.Comment: 24 pages, LaTex (AASTeX); includes 8 postscript figures and 4 Latex
tables. To appear in ApJ, Feb. 1, 1998. Postscript version of preprint can be
obtained from http://casa.colorado.edu/~anitak/pubs.htm
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