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41.
We consider the different characterizations of harmonic and subharmonic functions in terms of their mean values in balls and
on spheres. In particular, we prove a converse of an inequality of Beardon’s for subharmonic functions, and extend Rao’s integral
inequalities of Harnack type between these two means in general domains. 相似文献
42.
This paper proposes a novel ant colony optimisation (ACO) algorithm tailored for the hierarchical multi-label classification problem of protein function prediction. This problem is a very active research field, given the large increase in the number of uncharacterised proteins available for analysis and the importance of determining their functions in order to improve the current biological knowledge. Since it is known that a protein can perform more than one function and many protein functional-definition schemes are organised in a hierarchical structure, the classification problem in this case is an instance of a hierarchical multi-label problem. In this type of problem, each example may belong to multiple class labels and class labels are organised in a hierarchical structure—either a tree or a directed acyclic graph structure. It presents a more complex problem than conventional flat classification, given that the classification algorithm has to take into account hierarchical relationships between class labels and be able to predict multiple class labels for the same example. The proposed ACO algorithm discovers an ordered list of hierarchical multi-label classification rules. It is evaluated on sixteen challenging bioinformatics data sets involving hundreds or thousands of class labels to be predicted and compared against state-of-the-art decision tree induction algorithms for hierarchical multi-label classification. 相似文献
43.
44.
We study the spectrum of the Laplace operator of a complete minimal properly immersed hypersurface M in \({\mathbb{R}^{n+1}}\). (1) Under a volume growth condition on extrinsic balls and a condition on the unit normal at infinity, we prove that M has only essential spectrum consisting of the half line [0, +∞). This is the case when \({{\rm lim}_{\tilde{r}\to +\infty}\,\tilde{r}\kappa_i=0}\), where \({\tilde{r}}\) is the extrinsic distance to a point of M and κ i are the principal curvatures. (2) If the κ i satisfy the decay conditions \({|\kappa_i|\leq 1/\tilde{r}}\) and strict inequality is achieved at some point \({y\in M}\), then there are no eigenvalues. We apply these results to minimal graphic and multigraphic hypersurfaces. 相似文献
45.
Fused pyrazolopyrimidines. I. Pyrazolo[4,3-e]-v-triazolo[1,5-a]pyrimidine. A new heterocyclic system
Misbahul Ain Khan Antonio Carlos Carreira Freitas 《Journal of heterocyclic chemistry》1980,17(7):1603-1604
5-Azido-4-cyano-1-phenylpyrazole reacts with benzylcyanide in the presence of sodium methoxide to give the title ring system. 相似文献
46.
Elon Santos Correa Maria Teresinha A. Steiner Alex A. Freitas Celso Carnieri 《Numerical Algorithms》2004,35(2-4):373-388
Facility-location problems have several applications, such as telecommunications, industrial transportation and distribution. One of the most well-known facility-location problems is the p-median problem. This work addresses an application of the capacitated p-median problem to a real-world problem. We propose a genetic algorithm (GA) to solve the capacitated p-median problem. The proposed GA uses not only conventional genetic operators, but also a new heuristic “hypermutation” operator suggested in this work. The proposed GA is compared with a tabu search algorithm. 相似文献
47.
Pedro Freitas 《Journal of Functional Analysis》2007,251(1):376-398
We study the asymptotic expansion of the first Dirichlet eigenvalue of certain families of triangles and of rhombi as a singular limit is approached. In certain cases, which include isosceles and right triangles, we obtain the exact value of all the coefficients of the unbounded terms in the asymptotic expansion as the angle opening approaches zero, plus the constant term and estimates on the remainder. For rhombi and other triangle families such as isosceles triangles where now the angle opening approaches π, we have the first two terms plus bounds on the remainder. These results are based on new upper and lower bounds for these domains whose asymptotic expansions coincide up to the orders mentioned. Apart from being accurate near the singular limits considered, our lower bounds for the rhombus improve upon the bound by Hooker and Protter for angles up to approximately 22° and in the range (31°,54°). These results also show that the asymptotic expansion around the degenerate case of the isosceles triangle with vanishing angle opening depends on the path used to approach it. 相似文献
48.
AbstractThis article presents an overview of optical methodologies to aid the diagnosis and differentiation of thyroid and parathyroid tissues. In particular, we review the several techniques and associated methodologies that allow in vivo and ex vivo optical characterization of thyroid and parathyroid tissues. Emphasis is placed on the research potential of these techniques and whether intrinsic characteristics can provide useful contrast for the diagnosis of human thyroid and parathyroid malignant lesions. 相似文献
49.
50.
Taking into account effects of late energy injection, we examine big bang nucleosynthesis (BBN) constraints on axino dark matter scenarios with long-lived charged sleptons. We calculate 4-body slepton decays into the axino, a lepton, and a quark–antiquark pair since they govern late hadronic energy injection and associated BBN constraints. For supersymmetric hadronic axion models, we present the obtained hadronic BBN constraints and show that they can be more restrictive than the ones associated with catalyzed BBN via slepton-bound-state formation. From the BBN constraints on hadronic and electromagnetic energy release, we find new upper limits on the Peccei–Quinn scale. 相似文献