506 research outputs found
The fundamental gap of a kind of two dimensional sub-elliptic operator
This paper is concerned at the minimization fundamental gap problem for a
class of two-dimensional degenerate sub-elliptic operators. We establish
existence results for weak solutions, Sobolev embedding theorem and spectral
theory of sub-elliptic operators. We provide the existence and characterization
theorems for extremizing potentials when is subject to
norm constraint
A fleet arithmetic on overlay capacity of multi-aircraft cooperative detect base on transformed chameleon
In allusion to the particularity of Multi-Fighter Cooperative Detection, this paper analyzes the influence of different formation modes of the aircraft.. The framework of basic formation modes is established, moreover, the solutions of these models are also introduced. There is some disadvantage of gridding-method on real-time performance. A transformed chameleon method is used to divide up the big formation and cluster it into the basic ones. The rules-less formationsâ detect an overlay area and divided into basic ones, can be figured out on the ground of dividing results. In this way, we can reduce the fighter formations to calculate the overlay capacity fleetly. The simulation results indicate that the method meet the real-time needs with error permissibility
Empirical likelihood-based portmanteau tests for autoregressive moving average models with possible infinite variance innovation
It is an important task in the literature to check whether a fitted
autoregressive moving average (ARMA) model is adequate, while the currently
used tests may suffer from the size distortion problem when the underlying
autoregressive models have low persistence. To fill this gap, this paper
proposes two empirical likelihood-based portmanteau tests. The first one is
naive but can serve as a benchmark, and the second is for the case with
infinite variance innovations. The asymptotic distributions under the null
hypothesis are derived under mild moment conditions, and their usefulness is
demonstrated by simulation experiments and two real data examples.Comment: 23 pages, 2 figure
Evolution of magnetic component in Yang-Mills condensate dark energy models
The evolution of the electric and magnetic components in an effective
Yang-Mills condensate dark energy model is investigated. If the electric field
is dominant, the magnetic component disappears with the expansion of the
Universe. The total YM condensate tracks the radiation in the earlier Universe,
and later it becomes thus is similar to the cosmological constant.
So the cosmic coincidence problem can be avoided in this model. However, if the
magnetic field is dominant, holds for all time, suggesting that it
cannot be a candidate for the dark energy in this case.Comment: 12 pages, 4 figures, minor typos correcte
Mimicking Intermolecular Interactions of Tight ProteinâProtein Complexes for Small-Molecule Antagonists
Tight proteinâprotein interactions (Kd1000â
Ă
2) are highly challenging to disrupt with small molecules. Historically, the design of small molecules to inhibit proteinâprotein interactions has focused on mimicking the position of interface protein ligand side chains. Here, we explore mimicry of the pairwise intermolecular interactions of the native protein ligand with residues of the protein receptor to enrich commercial libraries for small-molecule inhibitors of tight proteinâprotein interactions. We use the high-affinity interaction (Kd=1â
nm) between the urokinase receptor (uPAR) and its ligand urokinase (uPA) to test our methods. We introduce three methods for rank-ordering small molecules docked to uPAR: 1)â
a new fingerprint approach that represents uPAâ˛s pairwise interaction energies with uPAR residues; 2)â
a pharmacophore approach to identify small molecules that mimic the position of uPA interface residues; and 3)â
a combined fingerprint and pharmacophore approach. Our work led to small molecules with novel chemotypes that inhibited a tight uPARâ
uPA proteinâprotein interaction with single-digit micromolar IC50 values. We also report the extensive work that identified several of the hits as either lacking stability, thiol reactive, or redox active. This work suggests that mimicking the binding profile of the native ligand and the position of interface residues can be an effective strategy to enrich commercial libraries for small-molecule inhibitors of tight proteinâprotein interactions
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