Reticulate evolutionary history and extensive introgression in mosquito species revealed by phylogenetic network analysis

The role of hybridization and subsequent introgression has been demonstrated in an increasing number of species. Recently, Fontaine et al. (Science, 347, 2015, 1258524) conducted a phylogenomic analysis of six members of the Anopheles gambiae species complex. Their analysis revealed a reticulate evolutionary history and pointed to extensive introgression on all four autosomal arms. The study further highlighted the complex evolutionary signals that the co-occurrence of incomplete lineage sorting (ILS) and introgression can give rise to in phylogenomic analyses. While tree-based methodologies were used in the study, phylogenetic networks provide a more natural model to capture reticulate evolutionary histories. In this work, we reanalyse the Anopheles data using a recently devised framework that combines the multispecies coalescent with phylogenetic networks. This framework allows us to capture ILS and introgression simultaneously, and forms the basis for statistical methods for inferring reticulate evolutionary histories. The new analysis reveals a phylogenetic network with multiple hybridization events, some of which differ from those reported in the original study. To elucidate the extent and patterns of introgression across the genome, we devise a new method that quantifies the use of reticulation branches in the phylogenetic network by each genomic region. Applying the method to the mosquito data set reveals the evolutionary history of all the chromosomes. This study highlights the utility of ‘network thinking’ and the new insights it can uncover, in particular in phylogenomic analyses of large data sets with extensive gene tree incongruence

A Fair and Secure Cluster Formation Process for Ad Hoc Networks

An efficient approach for organizing large ad hoc networks is to divide the nodes into multiple clusters and designate, for each cluster, a clusterhead which is responsible for holding intercluster control information. The role of a clusterhead entails rights and duties. On the one hand, it has a dominant position in front of the others because it manages the connectivity and has access to other node¿s sensitive information. But on the other hand, the clusterhead role also has some associated costs. Hence, in order to prevent malicious nodes from taking control of the group in a fraudulent way and avoid selfish attacks from suitable nodes, the clusterhead needs to be elected in a secure way. In this paper we present a novel solution that guarantees the clusterhead is elected in a cheat-proof manner

Dependence of the decoherence of polarization states in phase-damping channels on the frequency spectrum envelope of photons

We consider the decoherence of photons suffering in phase-damping channels. By exploring the evolutions of single-photon polarization states and two-photon polarization-entangled states, we find that different frequency spectrum envelopes of photons induce different decoherence processes. A white frequency spectrum can lead the decoherence to an ideal Markovian process. Some color frequency spectrums can induce asymptotical decoherence, while, some other color frequency spectrums can make coherence vanish periodically with variable revival amplitudes. These behaviors result from the non-Markovian effects on the decoherence process, which may give rise to a revival of coherence after complete decoherence.Comment: 7 pages, 4 figures, new results added, replaced by accepted versio

Effects of space flight factors on genetic diversity of Buchloe dactyloides seeds

The objective of this research was to investigate the effects of space flight factors on Buchloe dactyloides “Jingyin No.3” seeds. After the retrieval, basic turf characters of plants were tested. Among the 100 plants tested, 21 showed great change on phenotype characters, including leaf blade length and width, height, stem diameter, number of tillers, number and length of stolon, length of stolon inter node, leaf color and extent of leaf turning yellow. 33 primers were screened in inter-simple sequence repeats (ISSR) analysis to evaluate DNA variation between mutations and their ground controls. Results show that 15.6 reliable bands were generated by 7 primers, of which 12.9 (80.9%) were polymorphic. Based on the study, we can conclude that the space flight factors could induce inheritable mutagenic changes on B. dactyloides seeds, and do further research to demonstrate these changes in genetic material of the mutants.Key words: Genetic diversity, Buchloe dactyloides, spaceflight, inter-simple sequence repeats

Submm/mm Galaxy Counterpart Identification Using a Characteristic Density Distribution

We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer IRAC colors as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and SMA-confirmed counterparts to AzTEC sources across three fields (GOODS-N, GOODS-S, and COSMOS), we develop a non-parametric IRAC color-color characteristic density distribution (CDD), which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around SMGs and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beamsize (~18"), this technique identifies ~85 per cent of SMG counterparts. For much larger beamsizes (>30"), we report identification rates of 33-49 per cent. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the LMT and SCUBA-2 on JCMT.Comment: 30 pages, 9 figures, 5 tables. Accepted for publication in MNRA

Hysteretic Magnetotransport in SmB6 at Low Magnetic Fields

Utilizing Corbino disc structures, we have examined the magnetic field response of resistivity for the surface states of SmB6 on different crystalline surfaces at low temperatures. Our results reveal a hysteretic behavior whose magnitude depends on the magnetic field sweep rate and temperature. Although this feature becomes smaller when the field sweep is slower, a complete elimination or saturation is not observed in our slowest sweep-rate measurements, which is much slower than a typical magnetotransport trace. These observations cannot be explained by quantum interference corrections such as weak anti-localization. Instead, they are consistent with behaviors of glassy surface magnetic ordering, whose magnetic origin is most likely from samarium oxide (Sm2O3) forming on the surface during exposure to ambient conditions

An annealing-free aqueous-processed anatase TiO2 compact layer for efficient planar heterojunction perovskite solar cells

A facile aqueous-based fabrication scheme is developed for producing annealing-free anatase TiO2 (AF-TiO2) films that exhibit efficient electron transport properties in planar heterojunction perovskite solar cells (PSCs). AF-TiO2 films are fabricated by spin coating on a substrate a colloidal solution of anatase TiO2 nanoparticles (NPs) prepared via a low temperature hydrolytic sol-gel method. The resultant AF-TiO2 films show low electrical resistance, high transmittance in the visible and near-infrared regions and facilitation of high-quality perovskite film formation, which can be attributed to their homogeneous surface morphology and nanocrystallinity. The AF-TiO2 based PSCs achieve a power conversion efficiency (PCE) of 18.29 ± 0.18%, showing significant improvement compared to the control PSCs (PCE = 11.33 ± 0.32%) based on TiO2 films made by high-temperature annealing of amorphous TiO2 (HTA-TiO2)

Thermal Effect on Structure of Silver in Ion-Exchanged Soda-Lime Glasses and Aluminum-Doped Zinc Oxide Films

Heat treatment is commonly used during device processing in order to achieve specific functionalities of the devices. How a series of heat treatment applies to accomplish this goal can be found in the literature. However, specific properties of the devices after the treatment are more emphasized than the details of the structural modifications in the industrial applications. In this paper, it is intended to illustrate the fundamental changes in the structure due to heat treatment which result in the desired physical properties of the devices. Two study cases, Ag ion-exchanged soda-lime glasses and aluminum doped ZnO (AZO) films, were illustrated. The changes in chemical states, the structural modification during and after heat treatment are explored. By understanding how the metallic Ag formed and accumulated during annealing, an optimum heat treatment to grow the proper size and density of silver quantum dots in the films are possible. Post annealing effect on the AZO films shows that the crystallinity, the peak positions shifts, and grain sizes were changed after annealing. Both illustrated cases indicate thermally induced changes in chemical state, the stress release, and rearrangement of atoms in materials during and after annealing

Electronic structures of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films

We investigated the electronic structure of multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films using both optical spectroscopy and first-principles calculations. Using artificially stabilized hexagonal RMnO3, we extended the optical spectroscopic studies on the hexagonal multiferroic manganite system. We observed two optical transitions located near 1.7 eV and 2.3 eV, in addition to the predominant absorption above 5 eV. With the help of first-principles calculations, we attribute the low-lying optical absorption peaks to inter-site transitions from the oxygen states hybridized strongly with different Mn orbital symmetries to the Mn 3d3z2-r2 state. As the ionic radius of the rare earth ion increased, the lowest peak showed a systematic increase in its peak position. We explained this systematic change in terms of a flattening of the MnO5 triangular bipyramid