Interstellar medium oxygen abundances of dwarf irregular galaxies in Centaurus A and nearby groups

We present results of optical spectroscopy of 35 H ii regions from eight dwarf galaxies in the Centaurus A (Cen A) group. [O iii]λ4363 is detected in ESO272−G025 and ESO324−G024, and direct oxygen abundances of 12 + log (O/H) = 7.76 ± 0.09 and 7.94 ± 0.11 are derived, respectively. For the remaining galaxies, abundances are derived using common bright-line methods. To compare the influence of group environments on dwarf galaxies, we have also gathered data for additional dwarf irregular galaxies from the Cen A and the Sculptor groups from the literature. We have examined possible relationships between oxygen abundance, gas fraction, effective chemical yield and tidal indices. Despite large positive tidal indices for a number of Cen A dwarfs in the present sample, there is no clear separation between galaxies with positive tidal indices and galaxies with negative tidal indices in the luminosity-metallicity, metallicity-gas fraction and metallicity-tidal index diagrams. The H i surface mass density decreases with increasing positive tidal index, which is expected in strong tidal encounters. There are no strong trends between oxygen abundances or yields and projected distances of galaxies within their respective groups. We also present spectra for 13 H ii regions in three nearby dwarf irregular galaxies: DDO 47, NGC 3109 and Sextans B. For DDO 47, the [O iii]λ4363 oxygen abundance (7.92 ± 0.06) for the H ii region SHK91 No. 18 agrees with recently published values. For Sextans B, the [O iii]λ4363 oxygen abundance (7.80 ± 0.13) for H ii region SHK91 No. 5 agrees with published work in which O+ abundances were determined entirely from [O ii]λλ7320, 7330 fluxe

A Renormalization Group Analysis of Coupled Superconducting and Stripe Order in 1+1 Dimensions

In this paper we perform a renormalization group analysis on the 1+1 dimensional version of an effective field theory (previously proposed by Dung-Hai Lee, cond-mat/011393) describing (quantum) fluctuating stripe and superconductor orders. We find four possible phases corresponding to stripe order/disorder combined with superconducting order/disorder.Comment: 8 pages, 3 figures, revte

Complete Plastid Genome Sequence of the Chickpea (Cicer Arietinum) and the Phylogenetic Distribution of rps12 and clpP Intron Losses Among Legumes (Leguminosae)

Chickpea (Cicer arietinum, Leguminosae), an important grain legume, is widely used for food and fodder throughout the world. We sequenced the complete plastid genome of chickpea, which is 125,319 bp in size, and contains only one copy of the inverted repeat (IR). The genome encodes 108 genes, including 4 rRNAs, 29 tRNAs, and 75 proteins. The genes rps16, infA, and ycf4 are absent in the chickpea plastid genome, and ndhB has an internal stop codon in the 5′exon, similar to other legumes. Two genes have lost their introns, one in the 3′exon of the transpliced gene rps12, and the one between exons 1 and 2 of clpP; this represents the first documented case of the loss of introns from both of these genes in the same plastid genome. An extensive phylogenetic survey of these intron losses was performed on 302 taxa across legumes and the related family Polygalaceae. The clpP intron has been lost exclusively in taxa from the temperate “IR-lacking clade” (IRLC), whereas the rps12 intron has been lost in most members of the IRLC (with the exception of Wisteria, Callerya, Afgekia, and certain species of Millettia, which represent the earliest diverging lineages of this clade), and in the tribe Desmodieae, which is closely related to the tribes Phaseoleae and Psoraleeae. Data provided here suggest that the loss of the rps12 intron occurred after the loss of the IR. The two new genomic changes identified in the present study provide additional support of the monophyly of the IR-loss clade, and resolution of the pattern of the earliest-branching lineages in this clade. The availability of the complete chickpea plastid genome sequence also provides valuable information on intergenic spacer regions among legumes and endogenous regulatory sequences for plastid genetic engineering

The complete chloroplast genome sequence of Citrus sinensis (L.) Osbeck var 'Ridge Pineapple': organization and phylogenetic relationships to other angiosperms

BACKGROUND: The production of Citrus, the largest fruit crop of international economic value, has recently been imperiled due to the introduction of the bacterial disease Citrus canker. No significant improvements have been made to combat this disease by plant breeding and nuclear transgenic approaches. Chloroplast genetic engineering has a number of advantages over nuclear transformation; it not only increases transgene expression but also facilitates transgene containment, which is one of the major impediments for development of transgenic trees. We have sequenced the Citrus chloroplast genome to facilitate genetic improvement of this crop and to assess phylogenetic relationships among major lineages of angiosperms. RESULTS: The complete chloroplast genome sequence of Citrus sinensis is 160,129 bp in length, and contains 133 genes (89 protein-coding, 4 rRNAs and 30 distinct tRNAs). Genome organization is very similar to the inferred ancestral angiosperm chloroplast genome. However, in Citrus the infA gene is absent. The inverted repeat region has expanded to duplicate rps19 and the first 84 amino acids of rpl22. The rpl22 gene in the IRb region has a nonsense mutation resulting in 9 stop codons. This was confirmed by PCR amplification and sequencing using primers that flank the IR/LSC boundaries. Repeat analysis identified 29 direct and inverted repeats 30 bp or longer with a sequence identity ≥ 90%. Comparison of protein-coding sequences with expressed sequence tags revealed six putative RNA edits, five of which resulted in non-synonymous modifications in petL, psbH, ycf2 and ndhA. Phylogenetic analyses using maximum parsimony (MP) and maximum likelihood (ML) methods of a dataset composed of 61 protein-coding genes for 30 taxa provide strong support for the monophyly of several major clades of angiosperms, including monocots, eudicots, rosids and asterids. The MP and ML trees are incongruent in three areas: the position of Amborella and Nymphaeales, relationship of the magnoliid genus Calycanthus, and the monophyly of the eurosid I clade. Both MP and ML trees provide strong support for the monophyly of eurosids II and for the placement of Citrus (Sapindales) sister to a clade including the Malvales/Brassicales. CONCLUSION: This is the first complete chloroplast genome sequence for a member of the Rutaceae and Sapindales. Expansion of the inverted repeat region to include rps19 and part of rpl22 and presence of two truncated copies of rpl22 is unusual among sequenced chloroplast genomes. Availability of a complete Citrus chloroplast genome sequence provides valuable information on intergenic spacer regions and endogenous regulatory sequences for chloroplast genetic engineering. Phylogenetic analyses resolve relationships among several major clades of angiosperms and provide strong support for the monophyly of the eurosid II clade and the position of the Sapindales sister to the Brassicales/Malvales

Optical to near-infrared transmission spectrum of the warm sub-Saturn HAT-P-12b

We present the transmission spectrum of HAT-P-12b through a joint analysis of data obtained from the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) and Wide Field Camera 3 (WFC3) and Spitzer, covering the wavelength range 0.3-5.0 $\mu$m. We detect a muted water vapor absorption feature at 1.4 $\mu$m attenuated by clouds, as well as a Rayleigh scattering slope in the optical indicative of small particles. We interpret the transmission spectrum using both the state-of-the-art atmospheric retrieval code SCARLET and the aerosol microphysics model CARMA. These models indicate that the atmosphere of HAT-P-12b is consistent with a broad range of metallicities between several tens to a few hundred times solar, a roughly solar C/O ratio, and moderately efficient vertical mixing. Cloud models that include condensate clouds do not readily generate the sub-micron particles necessary to reproduce the observed Rayleigh scattering slope, while models that incorporate photochemical hazes composed of soot or tholins are able to match the full transmission spectrum. From a complementary analysis of secondary eclipses by Spitzer, we obtain measured depths of $0.042\%\pm0.013\%$ and $0.045\%\pm0.018\%$ at 3.6 and 4.5 $\mu$m, respectively, which are consistent with a blackbody temperature of $890^{+60}_{-70}$ K and indicate efficient day-night heat recirculation. HAT-P-12b joins the growing number of well-characterized warm planets that underscore the importance of clouds and hazes in our understanding of exoplanet atmospheres.Comment: 25 pages, 19 figures, accepted for publication in AJ, updated with proof correction

Biometric Performance as a Function of Gallery Size

Many developers of biometric systems start with modest samples before general deployment. They are interested in how their systems will work with much larger samples. We evaluated the effect of gallery size on biometric performance. Identification rates describe the performance of biometric identification, whereas ROC-based measures describe the performance of biometric authentication (verification). Therefore, we examined how increases in gallery size affected identification rates (i.e., Rank-1 Identification Rate, or Rank-1 IR) and ROC-based measures such as equal error rate (EER). We studied these phenomena with synthetic data as well as real data from a face recognition study. It is well known that the Rank-1 IR declines with increasing gallery size. We have provided further insight into this decline. We have shown that this relationship is linear in log(Gallery Size). We have also shown that this decline can be counteracted with the inclusion of additional information (features) for larger gallery sizes. We have also described the curves which can be used to predict how much additional information is required to stabilize the Rank-1 IR as a function of gallery size. These equations are also linear in log(gallery size). We have also shown that the entire ROC curve is not systematically affected by gallery size, and so ROC-based scalar performance metrics such as EER are also stable across gallery size.Comment: 19 pages, 9 Figures, 0 Table

Sub-5 keV electron-beam lithography in hydrogen silsesquioxane resist

We fabricated 9–30 nm half-pitch nested Ls and 13–15 nm half-pitch dot arrays, using 2 keV electron-beam lithography with hydrogen silsesquioxane (HSQ) as the resist. All structures with 15 nm half-pitch and above were fully resolved. We observed that the 9 and 10-nm half-pitch nested Ls and the 13-nm-half-pitch dot array contained some resist residues. We obtained good agreement between experimental and Monte-Carlo-simulated point-spread functions at energies of 1.5, 2, and 3 keV. The long-range proximity effect was minimal, as indicated by simulated and patterned 30 nm holes in negative-tone resist.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088)National Science Foundation (U.S.) (Grant CMMI-0609241)China Scholarship CouncilNational Science Foundation (U.S.). Graduate Research Fellowshi