The genetics of symbiotic nitrogen fixation: comparative genomics of 14 Rhizobia Strains by resolution of protein clusters.

The symbiotic relationship between legumes and nitrogen fixing bacteria is critical for agriculture, as it may have profound impacts on lowering costs for farmers, on land sustainability, on soil quality, and on mitigation of greenhouse gas emissions. However, despite the importance of the symbioses to the global nitrogen cycling balance, very few rhizobial genomes have been sequenced so far, although there are some ongoing efforts in sequencing elite strains. In this study, the genomes of fourteen selected strains of the order Rhizobiales, all previously fully sequenced and annotated, were compared to assess differences between the strains and to investigate the feasibility of defining a core ?symbiome??the essential genes required by all rhizobia for nodulation and nitrogen fixation. Comparison of these whole genomes has revealed valuable information, such as several events of lateral gene transfer, particularly in the symbiotic plasmids and genomic islands that have contributed to a better understanding of the evolution of contrasting symbioses. Unique genes were also identified, as well as omissions of symbiotic genes that were expected to be found. Protein comparisons have also allowed the identification of a variety of similarities and differences in several groups of genes, including those involved in nodulation, nitrogen fixation, production of exopolysaccharides, Type I to Type VI secretion systems, among others, and identifying some key genes that could be related to host specificity and/or a better saprophytic ability. However, while several significant differences in the type and number of proteins were observed, the evidence presented suggests no simple core symbiome exists. A more abstract systems biology concept of nitrogen fixing symbiosis may be required. The results have also highlighted that comparative genomics represents a valuable tool for capturing specificities and generalities of each genome.bitstream/item/74069/1/ID-34062.pd

Structure, bonding and morphology of hydrothermally synthesised xonotlite

The authors have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically prepared, semicrystalline phase with Ca/Si=1, the authors have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250 degrees C. Analysis in each case was by X-ray photoelectron spectroscopy, environmental scanning electron microscopy and X-ray diffraction. The authors’ use of a much lower water/solid ratio has indirectly confirmed the ‘through solution’ mechanism of xonotlite formation, where silicate dissolution is a key precursor of xonotlite formation. Concerning the role of temperature, too low a temperature (~200 degrees C) fails to yield xonotlite or leads to increased number of structural defects in the silicate chains of xonotlite and too high a temperature (>250 degrees C) leads to degradation of the xonotlite structure, through leaching of interchain calcium. Synthesis duration meanwhile leads to increased silicate polymerisation due to diminishing of the defects in the silicate chains and more perfect crystal morphologies

Patterns of Northern Ireland trade by destination, product and business characteristics: 2012 to 2016

New figures show that Northern Irish businesses conducted most international trade with the Republic of Ireland, accounting for around 27% of exports and 23% of imports; however, a separate data source, which includes intra-country trade, highlights that the rest of the UK remains Northern Ireland’s biggest market. More than 50% of Northern Ireland’s goods exports went to just two countries, the Republic of Ireland and the USA; the Republic of Ireland was the most important destination for food and live animals, while the USA was the most important destination for machinery and transport. Food and live animals represented around 33% of the total Northern Irish exports going to the Republic of Ireland, of which the top sub-category was milk and cream products. Almost 70% of exporting businesses in Northern Ireland were small (employing 0 to 49 workers), selling a small number of products to a few markets. Domestic businesses in Northern Ireland were less diversified in terms of products and markets compared with foreign-owned businesses. The biggest proportion of two-way trade in similar products was in food and live animals, suggesting integration of supply-chains in this category

Standalone engine simulator (SAES), Engine Dynamics simulator (EDS) Xerox Sigma 5 interface hardware manual

The ESS-EDS and EDS-Sigma interfaces within the standalone engine simulator are described. The operation of these interfaces, including the definition and use of special function signals and data flow paths within them during data transfers, is presented along with detailed schematics and circuit layouts of the described equipment

The origins of X-ray emission from the hotspots of FRII radio sources

We use new and archival Chandra data to investigate the X-ray emission from a large sample of compact hotspots of FRII radio galaxies and quasars from the 3C catalogue. We find that only the most luminous hotspots tend to be in good agreement with the predictions of a synchrotron self-Compton model with equipartition magnetic fields. At low hotspot luminosities inverse-Compton predictions are routinely exceeded by several orders of magnitude, but this is never seen in more luminous hotspots. We argue that an additional synchrotron component of the X-ray emission is present in low-luminosity hotspots, and that the hotspot luminosity controls the ability of a given hotspot to produce synchrotron X-rays, probably by determining the high-energy cutoff of the electron energy spectrum. It remains plausible that all hotspots are close to the equipartition condition.Comment: 49 pages, 16 figures. ApJ accepted. Revised version fixes a typo in one of the Tables and corrects a statement about 3C27

The nature of a broad line radio galaxy: Simultaneous RXTE and Chandra HETG observations of 3C 382

We present the results from simultaneous chandra and rxte observations of the X-ray bright Broad-Line Radio Galaxy (BLRG) 3C 382. The long (120 ks) exposure with chandra HETG allows a detailed study of the soft X-ray continuum and of the narrow component of the Fe Kalpha line. The rxte PCA data are used to put an upper limit on the broad line component and constrain the hard X-ray continuum. A strong soft excess below 1 keV is observed in the time-averaged HETG spectrum, which can be parameterized with a steep power law or a thermal model. The flux variability at low energies indicates that the origin of the soft excess cannot be entirely ascribed to the circumnuclear diffuse emission, detected by chandra on scales of 20-30 arcsec (22-33 kpc). A narrow (sigma<90 eV) Fe Kalpha line (with EW< 100 eV) is observed by the chandra HEG. Similar values for the line parameters are measured by the rxte PCA, suggesting that the contribution from a broad line component is negligible. The fact that the exposure is split into two observations taken three days apart allows us to investigate the spectral and temporal evolution of the source on different timescales. Significant flux variability associated with spectral changes is observed on timescales of hours and days. The spectral variability is similar to that observed in radio-quiet AGN ruling out a jet-dominated origin of the X-rays.Comment: 19 pages, 10 figures, 3 tables, accepted for publication in Ap

The interaction of class and gender in illness narratives

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2008 BSA Publications Ltd.Perspectives on gender and identity that emphasize variability of performance, local context and individual agency have displaced earlier paradigms.These are now perceived to have supported gender stereotypes and language ideologies by emphasizing gender difference and homogeneity within genders. In a secondary analysis of health and illness narratives we explore the interaction of class and gender in individuals' constructions of gendered identity. High social class men perform gender in particularly varied ways and we speculate that this variable repertoire, including the use of what was once termed `women's language', is linked to a capacity to maintain social distinction and authority. Men's performance of conventional masculinity is often threatened by both the experience of illness and being interviewed about personal experience. Lower social class women in particular demonstrate an intensification of a pre-existing informal family and support group culture, marking successful members by awarding them the accolade of being `lovely'.ESR

870 micron observations of nearby 3CRR radio galaxies

We present submillimeter continuum observations at 870 microns of the cores of low redshift 3CRR radio galaxies, observed at the Heinrich Hertz Submillimeter Telescope. The cores are nearly flat spectrum between the radio and submillimeter which implies that the submillimeter continuum is likely to be synchrotron emission and not thermal emission from dust. The emitted power from nuclei detected at optical wavelengths and in the X-rays is similar in the submillimeter, optical and X-rays. The submillimeter to optical and X-ray power ratios suggest that most of these sources resemble misdirected BL Lac type objects with synchrotron emission peaking at low energies. However we find three exceptions, the FR I galaxy 3C264 and the FR II galaxies 3C390.3 and 3C338 with high X-ray to submillimeter luminosity ratios. These three objects are candidate high or intermediate energy peaked BL Lac type objects. With additional infrared observations and from archival data, we compile spectral energy distributions (SEDs) for a subset of these objects. The steep dips observed near the optical wavelengths in many of these objects suggest that extinction inhibits the detection and reduces the flux of optical continuum core counterparts. High resolution near or mid-infrared imaging may provide better measurements of the underlying synchrotron emission peak.Comment: accepted for publication in A

Adiabatic-antiadiabatic crossover in a spin-Peierls chain

We consider an XXZ spin-1/2 chain coupled to optical phonons with non-zero frequency $\omega_0$. In the adiabatic limit (small $\omega_0$), the chain is expected to spontaneously dimerize and open a spin gap, while the phonons become static. In the antiadiabatic limit (large $\omega_0$), phonons are expected to give rise to frustration, so that dimerization and formation of spin-gap are obtained only when the spin-phonon interaction is large enough. We study this crossover using bosonization technique. The effective action is solved both by the Self Consistent Harmonic Approximation (SCHA)and by Renormalization Group (RG) approach starting from a bosonized description. The SCHA allows to analyze the lowfrequency regime and determine the coupling constant associated with the spin-Peierls transition. However, it fails to describe the SU(2) invariant limit. This limit is tackled by the RG. Three regimes are found. For $\omega_0\ll\Delta_s$, where $\Delta_s$ is the gap in the static limit $\omega_0\to 0$, the system is in the adiabatic regime, and the gap remains of order $\Delta_s$. For $\omega_0>\Delta_s$, the system enters the antiadiabatic regime, and the gap decreases rapidly as $\omega_0$ increases. Finally, for $\omega_0>\omega_{BKT}$, where $\omega_{BKT}$ is an increasing function of the spin phonon coupling, the spin gap vanishes via a Berezinskii-Kosterlitz-Thouless transition. Our results are discussed in relation with numerical and experimental studies of spin-Peierls systems.Comment: Revtex, 21 pages, 5 EPS figures (v1); 23 pages, 6 EPS figures, more detailed comparison with ED results, referenes added (v2