384 research outputs found

    Comparisons of bacterial community within the abdomens of Formosan subterranean termites, fresh- and alcohol-stored, from their native (China) and introduced (U.S.) range

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    The Formosan subterranean termite (FST), a pest species native to China and introduced to the U.S., is obligatorily dependent on its gut microbiota. Using high-throughput 16S rRNA gene sequencing, the effects of long-term alcohol storage and geographic location on the bacteria composition of the FST colonies were investigated. Initial studies found the use of amplified ribosomal DNA restriction analysis (ARDRA) to be unpractical due to its higher costs compared to the direct sequencing of 16S rRNA gene sequences. Using nine FST colonies consisting of fresh and alcohol-stored Lousiana FST colonies and alcohol-stored China FST colonies, 237 bacteria ribotypes were identified from 1876 clones based on a \u3c97% sequence similarity criterion. Twenty-four of the ribotypes were artifact sequences and were excluded from subsequent analyses. Most of the remaining ribotypes were novel (70.89% of total ribotypes). Termite-specific bacteria dominated the bacteria composition in the FSTs (66.45% of total clones). Only 3.34% of the total clones were similar to environmental bacteria. Thirteen bacteria phyla were represented: Bacteroidetes (42.91% of total clones), Firmicutes (30.49%), Spirochaetes (11.30%), Actinobacteria (5.70%), Proteobacteria (2.24%), Tenericutes (1.55%), candidate division Termite Group 1 (1.01%), candidate division TM7 (0.64%), Verrucomicrobia (0.59%), Planctomycetes (0.48%), candidate division Synergistes (0.21%), candidate division ZB3 (0.05%) and Cyanobacteria (0.05%). The Bacteroidetes ribotype previously identified to be dominant in FST from Japan, was also among the dominant phyla in all the FST colonies of this study (38.71% of total clones). Differential DNA degradation occurred in the alcohol-stored FST samples, leading to higher proportions of the gram-positive bacteria such as Actinobacteria, Bacilli and Clostridia and lower proportions of the gram-negative bacteria such as Bacteroidetes and Spirochaetes compared to the fresh FST samples. Long-term alcohol storage of the FST led to the discovery of less abundant ribotypes when the predominant ribotype was reduced. Geographic region did not show detectable influence on the FST bacteria composition. This was likely due to the multiple introduction of FST from China into the U.S. Future studies using T-RFLP to sample the bacteria community from FST colonies randomized across each geographical region would be useful in confirming the observations from this study

    Comparison of the Bacterial Symbiont Composition of the Formosan Subterranean Termite from its Native and Introduced Range

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    We investigated the bacterial composition in the gut of Formosan subterranean termites (FST), Coptotermes formosanus Shiraki, collected from southern China (native range) vs. Louisiana, U. S. (introduced range) using 16S rRNA gene sequencing. Overall, we identified 213 bacteria ribotypes from thirteen phyla. The enemy release hypothesis could not be invoked to explain invasion success of FST since no pathogens were found among the bacterial gut community regardless of geographic origin. Invasion of new habitats did not significantly change the bacteria composition. Apparently, the tight co-evolutionary link between termites and their gut flora maintains a certain association of species and functional groups. Ribotype richness, bacteria diversity, and proportions of detected phyla were not influenced by geographic origin of FST samples; however, these parameters were affected by storage of the samples. Ethanol storage of termite samples (5 yrs) increased the relative proportions of gram-positive bacteria versus gram-negative bacteria

    Long-Term Prediction of Emergency Department Revenue and Visitor Volume Using Autoregressive Integrated Moving Average Model

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    This study analyzed meteorological, clinical and economic factors in terms of their effects on monthly ED revenue and visitor volume. Monthly data from January 1, 2005 to September 30, 2009 were analyzed. Spearman correlation and cross-correlation analyses were performed to identify the correlation between each independent variable, ED revenue, and visitor volume. Autoregressive integrated moving average (ARIMA) model was used to quantify the relationship between each independent variable, ED revenue, and visitor volume. The accuracies were evaluated by comparing model forecasts to actual values with mean absolute percentage of error. Sensitivity of prediction errors to model training time was also evaluated. The ARIMA models indicated that mean maximum temperature, relative humidity, rainfall, non-trauma, and trauma visits may correlate positively with ED revenue, but mean minimum temperature may correlate negatively with ED revenue. Moreover, mean minimum temperature and stock market index fluctuation may correlate positively with trauma visitor volume. Mean maximum temperature, relative humidity and stock market index fluctuation may correlate positively with non-trauma visitor volume. Mean maximum temperature and relative humidity may correlate positively with pediatric visitor volume, but mean minimum temperature may correlate negatively with pediatric visitor volume. The model also performed well in forecasting revenue and visitor volume

    AMiBA Wideband Analog Correlator

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    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband IF distribution, backend signal processing and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.Comment: 28 pages, 23 figures, ApJ in press

    AMiBA: Broadband Heterodyne CMB Interferometry

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    The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first science results on the detection of galaxy clusters via the Sunyaev Zel'dovich effect. The science objectives required small reflectors in order to sample large scale structures (20') while interferometry provided modest resolutions (2'). With these constraints, we designed for the best sensitivity by utilizing the maximum possible continuum bandwidth matched to the atmospheric window at 86-102GHz, with dual polarizations. A novel wide-band analog correlator was designed that is easily expandable for more interferometer elements. MMIC technology was used throughout as much as possible in order to miniaturize the components and to enhance mass production. These designs will find application in other upcoming astronomy projects. AMiBA is now in operations since 2006, and we are in the process to expand the array from 7 to 13 elements.Comment: 10 pages, 6 figures, ApJ in press; a version with high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/mtc_highreso.pd

    Constraining Intra-cluster Gas Models with AMiBA13

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    Clusters of galaxies have been used extensively to determine cosmological parameters. A major difficulty in making best use of Sunyaev-Zel'dovich (SZ) and X-ray observations of clusters for cosmology is that using X-ray observations it is difficult to measure the temperature distribution and therefore determine the density distribution in individual clusters of galaxies out to the virial radius. Observations with the new generation of SZ instruments are a promising alternative approach. We use clusters of galaxies drawn from high-resolution adaptive mesh refinement (AMR) cosmological simulations to study how well we should be able to constrain the large-scale distribution of the intra-cluster gas (ICG) in individual massive relaxed clusters using AMiBA in its configuration with 13 1.2-m diameter dishes (AMiBA13) along with X-ray observations. We show that non-isothermal beta models provide a good description of the ICG in our simulated relaxed clusters. We use simulated X-ray observations to estimate the quality of constraints on the distribution of gas density, and simulated SZ visibilities (AMiBA13 observations) for constraints on the large-scale temperature distribution of the ICG. We find that AMiBA13 visibilities should constrain the scale radius of the temperature distribution to about 50% accuracy. We conclude that the upgraded AMiBA, AMiBA13, should be a powerful instrument to constrain the large-scale distribution of the ICG.Comment: Accepted for publication in The Astrophysical Journal, 12 pages, 9 figure

    AMiBA: scaling relations between the integrated Compton-y and X-ray derived temperature, mass, and luminosity

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    We investigate the scaling relations between the X-ray and the thermal Sunyaev-Zel'dovich Effect (SZE) properties of clusters of galaxies, using data taken during 2007 by the Y.T. Lee Array for Microwave Background Anisotropy (AMiBA) at 94 GHz for the six clusters A1689, A1995, A2142, A2163, A2261, and A2390. The scaling relations relate the integrated Compton-y parameter Y_{2500} to the X-ray derived gas temperature T_{e}, total mass M_{2500}, and bolometric luminosity L_X within r_{2500}. Our results for the power-law index and normalization are both consistent with the self-similar model and other studies in the literature except for the Y_{2500}-L_X relation, for which a physical explanation is given though further investigation may be still needed. Our results not only provide confidence for the AMiBA project but also support our understanding of galaxy clusters.Comment: Accepted by ApJ; 8 pages, 3 figures, 5 table

    The Yuan-Tseh Lee Array for Microwave Background Anisotropy

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    The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the first interferometer dedicated to studying the cosmic microwave background (CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the contributions from foreground synchrotron radiation and Galactic dust emission. The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific operations began with the detection of a number of clusters of galaxies via the thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing data in order to study the structure of dark matter. We also compare our data with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd
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