5,090 research outputs found
Measurement of the Base Noise of Hermetic Compressor and Its Application to the Design of Muffler System and Compressor Shell
Complements of hypersurfaces, variation maps and minimal models of arrangements
We prove the minimality of the CW-complex structure for complements of
hyperplane arrangements in by using the theory of Lefschetz
pencils and results on the variation maps within a pencil of hyperplanes. This
also provides a method to compute the Betti numbers of complements of
arrangements via global polar invariants
Electronic density of states derived from thermodynamic critical field curves for underdoped La-Sr-Cu-O
Thermodynamic critical field curves have been measured for
over the full range of carrier concentrations
where superconductivity occurs in order to determine changes in the normal
state density of states with carrier concentration. There is a substantial
window in the plane where the measurements are possible because the
samples are both thermodynamically reversible and the temperature is low enough
that vortex fluctuations are not important. In this window, the data fit
Hao-Clem rather well, so this model is used to determine and
for each temperature and carrier concentration. Using N(0) and the ratio of the
energy gap to transition temperature, , as fitting
parameters, the curves give over the
whole range of . Values of N(0) remain rather constant in the optimum-doped
and overdoped regime, but drops quickly toward zero in the underdoped regime.
Anisotropic photo-induced magnetism of a thin film
A magneto-optically active thin film of RbCo[Fe(CN)]
HO has been prepared using a sequential assembly method. Upon
irradiation with light and at 5 K, the net magnetization of the film increased
when the surface of the film was oriented parallel to the external magnetic
field of 0.1 T. However, when the surface of the film was perpendicular to the
field, the net magnetization \emph{decreased} upon irradiation. The presence of
dipolar fields and the low-dimensional nature of the system are used to
describe the orientation dependence of the photo-induced magnetization. The
ability to increase or decrease the photo-induced magnetization by changing the
orientation of the system with respect to the field is a new phenomenon that
may be useful in future device applications.Comment: 10 pages, 2 figures, 1 tabl
Arabidopsis ABCG34 contributes to defense against necrotrophic pathogens by mediating the secretion of camalexin
Plant pathogens cause huge yield losses. Plant defense often depends on toxic secondary metabolites that inhibit pathogen growth. Because most secondary metabolites are also toxic to the plant, specific transporters are needed to deliver them to the pathogens. To identify the transporters that function in plant defense, we screened Arabidopsis thaliana mutants of full-size ABCG transporters for hypersensitivity to sclareol, an antifungal compound. We found that atabcg34 mutants were hypersensitive to sclareol and to the necrotrophic fungi Alternaria brassicicola and Botrytis cinerea. AtABCG34 expression was induced by A. brassicicola inoculation as well as by methyl-jasmonate, a defense-related phytohormone, and AtABCG34 was polarly localized at the external face of the plasma membrane of epidermal cells of leaves and roots. atabcg34 mutants secreted less camalexin, a major phytoalexin in A. thaliana, whereas plants overexpressing AtABCG34 secreted more camalexin to the leaf surface and were more resistant to the pathogen. When treated with exogenous camalexin, atabcg34 mutants exhibited hypersensitivity, whereas BY2 cells expressing AtABCG34 exhibited improved resistance. Analyses of natural Arabidopsis accessions revealed that AtABCG34 contributes to the disease resistance in naturally occurring genetic variants, albeit to a small extent. Together, our data suggest that AtABCG34 mediates camalexin secretion to the leaf surface and thereby prevents A. brassicicola infection.117Ysciescopu
Classical generalized constant coupling model for geometrically frustrated antiferromagnets
A generalized constant coupling approximation for classical geometrically
frustrated antiferromagnets is presented. Starting from a frustrated unit we
introduce the interactions with the surrounding units in terms of an internal
effective field which is fixed by a self consistency condition. Results for the
magnetic susceptibility and specific heat are compared with Monte Carlo data
for the classical Heisenberg model for the pyrochlore and kagome lattices. The
predictions for the susceptibility are found to be essentially exact, and the
corresponding predictions for the specific heat are found to be in very good
agreement with the Monte Carlo results.Comment: 4 pages, 3 figures, 2 columns. Discussion about the zero T value of
the pyrochlore specific heat correcte
Effects of 3D-printed polycaprolactone/��-tricalcium phosphate membranes on guided bone regeneration
This study was conducted to compare 3D-printed polycaprolactone (PCL) and polycaprolactone/��-tricalcium phosphate (PCL/��-TCP) membranes with a conventional commercial collagen membrane in terms of their abilities to facilitate guided bone regeneration (GBR). Fabricated membranes were tested for dry and wet mechanical properties. Fibroblasts and preosteoblasts were seeded into the membranes and rates and patterns of proliferation were analyzed using a kit-8 assay and by scanning electron microscopy. Osteogenic differentiation was verified by alizarin red S and alkaline phosphatase (ALP) staining. An in vivo experiment was performed using an alveolar bone defect beagle model, in which defects in three dogs were covered with different membranes. CT and histological analyses at eight weeks after surgery revealed that 3D-printed PCL/��-TCP membranes were more effective than 3D-printed PCL, and substantially better than conventional collagen membranes in terms of biocompatibility and bone regeneration and, thus, at facilitating GBR. ? 2017 by the authors. Licensee MDPI, Basel, Switzerland.118Ysciescopu
Slightly Non-Minimal Dark Matter in PAMELA and ATIC
We present a simple model in which dark matter couples to the standard model
through a light scalar intermediary that is itself unstable. We find this model
has several notable features, and allows a natural explanation for a surplus of
positrons, but no surplus of anti-protons, as has been suggested by early data
from PAMELA and ATIC. Moreover, this model yields a very small nucleon
coupling, well below the direct detection limits. In this paper we explore the
effect of this model in both the early universe and in the galaxy.Comment: 7 pages, 6 figures, v3: updated for new data, added discussion of
Ferm
Electrical and thermal conductivities of reduced graphene oxide/polystyrene composites
The author reports an experimental study of electrical and thermal transport in reduced graphene oxide (RGO)/polystyrene (PS) composites. The electrical conductivity (sigma) of RGO/PS composites with different RGO concentrations at room temperature shows a percolation behavior with the percolation threshold of similar to 0.25 vol. %. Their temperature-dependent electrical conductivity follows Efros-Shklovskii variable range hopping conduction in the temperature range of 30-300K. The thermal conductivity (kappa) of composites is enhanced by similar to 90% as the concentration is increased from 0 to 10 vol. %. The thermal conductivity of composites approximately linearly increases with increasing temperature from 150 to 300 K. Composites with a higher concentration show a stronger temperature dependence in the thermal conductivity. (C) 2014 AIP Publishing LLC
Likelihood Geometry
We study the critical points of monomial functions over an algebraic subset
of the probability simplex. The number of critical points on the Zariski
closure is a topological invariant of that embedded projective variety, known
as its maximum likelihood degree. We present an introduction to this theory and
its statistical motivations. Many favorite objects from combinatorial algebraic
geometry are featured: toric varieties, A-discriminants, hyperplane
arrangements, Grassmannians, and determinantal varieties. Several new results
are included, especially on the likelihood correspondence and its bidegree.
These notes were written for the second author's lectures at the CIME-CIRM
summer course on Combinatorial Algebraic Geometry at Levico Terme in June 2013.Comment: 45 pages; minor changes and addition
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