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The constrained relay node placement problem in a wireless sensor network seeks the deployment of a minimum number of relay nodes (RNs) in a set of candidate locations in the network to satisfy specific requirements, such as connectivity or survivability. In this paper, we study the constrained relay node placement problem in an energy-harvesting network in which the energy harvesting potential of the candidate locations are known a priori. Our aim is to place a minimum number of relay nodes, to achieve connectivity or survivability, while ensuring that the relay nodes harvest large amounts of ambient energy. We present the connectivity and survivability problems, discuss their NP-hardness, and propose polynomial time O(1)-approximation algorithms with low approximation ratios to solve them. We validate the effectiveness of our algorithms through numerical results to show that the RNs placed by our algorithms harvest 50% more energy on average than those placed by the algorithms unaware of energy harvesting. We also develop a unified-mixed integer linear program (MILP)-based formulation to compute a lower bound of the optimal solution for minimum relay node placement and demonstrate that the results of our proposed algorithms were on average within 1.5 times of the optimal.

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Nasopharyngeal carcinoma (NPC) is a squamous-cell carcinoma that arises in the epithelial lining of the nasopharynx [1]. This neoplasm has a notable ethnic and geographic distribution, being of high prevalence in southern China but rare in other parts of the world [2]. Familial clustering of NPC has been observed in diverse populations [3]. Elevated levels of circulating free Epstein-Barr virus (EBV) DNA and EBV-related antibodies in sera, as well as EBV DNA in tumor cells, have been consistently detected in individuals with NPC [4,5]. These studies have revealed that the risk factors of NPC are both environmental and genetic. How the risk factors interact, and the genes that are involved in the development of NPC, are not well understood [6].

The development and partial characterization of turkey genomic libraries enriched for TG, GAT, and CCT simple sequence repeats (SSR) are described. The primary library, established using conventional methods, was enriched for each of the three SSR by single-primer polymerase chain reaction (PCR). The three enriched libraries were screened by standard hybridization and washing protocols under moderate to high stringency conditions. The utility of a fraction of the markers was evaluated based on the polymorphism of PCR-amplified products in a backcross reference DNA panel. The panel consisted of genomic DNA samples from three backcrossed families developed from a cross of a wild male turkey to three inbred Orlopp line C females. A total of 181 sequences from positive clones have been characterized and deposited in GenBank. About 60% of the 60 primer pairs designed from SSR-containing sequences detected polymorphism in the reference DNA panel. The turkey genomic DNA reference panel, the enriched libraries, and the markers described here provide an opportunity to begin to characterize the turkey genome and to develop a useful public genetic map for this economically important species.

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Hexagonal single-crystal AlN nanowires with straight or zigzag morphologies were successfully synthesized by the reaction of aluminum alloy in an ammonia/nitrogen atmosphere at 1100 degrees C. It is found that the crystal tropism of the nanowires is along [0001], whereas the growth directions of the zigzag nanowires shift between [2111] and [2111].