3,539 research outputs found

    Genomic and proteomic evidence supporting the division of the plant pathogen Ralstonia solanacearum into three species

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    Background The increased availability of genome sequences has advanced the development of genomic distance methods to describe bacterial diversity. Results of these fast-evolving methods are highly correlated with those of the historically standard DNA-DNA hybridization technique. However, these genomic-based methods can be done more rapidly and less expensively and are less prone to technical and human error. They are thus a technically accessible replacement for species delineation. Here, we use several genomic comparison methods, supported by our own proteomic analyses and metabolic characterization as well as previously published DNA-DNA hybridization analyses, to differentiate members of the Ralstonia solanacearum species complex into three species. This pathogen group consists of diverse and widespread strains that cause bacterial wilt disease on many different plants. Results We used three different methods to compare the complete genomes of 29 strains from the R. solanacearum species complex. In parallel we profiled the proteomes of 73 strains using Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS). Proteomic profiles together with genomic sequence comparisons consistently and comprehensively described the diversity of the R. solanacearum species complex. In addition, genome-driven functional phenotypic assays excitingly supported an old hypothesis (Hayward et al. (J Appl Bacteriol 69:269–80, 1990)), that closely related members of the R. solanacearum could be identified through a simple assay of anaerobic nitrate metabolism. This assay allowed us to clearly and easily differentiate phylotype II and IV strains from phylotype I and III strains. Further, genomic dissection of the pathway distinguished between proposed subspecies within the current phylotype IV. The assay revealed large scale differences in energy production within the R. solanacearum species complex, indicating coarse evolutionary distance and further supporting a repartitioning of this group into separate species. Conclusions Together, the results of these studies support the proposed division of the R. solanacearum species complex into three species, consistent with recent literature, and demonstrate the utility of proteomic and genomic approaches to delineate bacterial species. (Résumé d'auteur

    Linking Maternal Socialization of Emotion Regulation to Adolescents’ Co-rumination With Peers

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    Mounting research supports that co-rumination, the tendency to seek peer support by engaging in extensive negatively focused discussion, is a risk factor for adolescent psychopathology. It is unclear, though, how this interpersonal tendency develops. Parental responses to adolescents’ negative affect likely shape how youth utilize peer relationships to regulate distress, as they shift to reliance on peer support during this developmental stage. For example, nonsupportive parental responses may fail to instill healthy regulation strategies, resulting in ineffective forms of peer support, such as co-rumination. Conversely, high levels of supportive parental responses to adolescents’ negative affect may motivate youth to also express more negative affect with peers, leading to co-rumination. Eighty-nine healthy adolescents (9-17) and their mothers completed surveys and a support-seeking interaction. Only supportive maternal responses, including maternal affection, were associated with adolescents’ co-rumination. These analyses indicate that some forms of parental support are associated with adolescents’ tendency to co-ruminate

    Life Beneath Glacial Ice - Earth(!) Mars(?) Europa(?)

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    We are investigating a set of cold springs that deposit sulfur and carbonate minerals on the surface of a Canadian arctic glacier. The spring waters and mineral deposits contain microorganisms, as well as clear evidence that biological processes mediate subglacial chemistry, mineralogy, and isotope fractionation . The formation of native sulphur and associated deposits are related to bacterially mediated reduction and oxidation of sulphur below the glacier. A non-volcanic, topography driven geothermal system, harboring a microbiological community, operates in an extremely cold environment and discharges through solid ice. Microbial life can thus exist in isolated geothermal refuges despite long-term subfreezing surface conditions. Earth history includes several periods of essentially total glaciation. lee in the near subsurface of Mars may have discharged liquid water in the recent past Cracks in the ice crust of Europa have apparently allowed the release of water to the surface. Chemolithotrophic bacteria, such as those in the Canadian springs, could have survived beneath the ice of "Snowball Earth", and life forms with similar characteristics might exist beneath the ice of Mars or Europa. Discharges of water from such refuges may have brought to the surface living microbes, as well as longlasting chemical, mineralogical, and isotopic indications of subsurface life

    Sustainability of the chemical manufacturing industry - Towards a new paradigm?

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    This paper describes the current situation of the chemicalmanufacturingindustry, with special reference to Europe and looks to the future sustainability demands on the sector, and the implications of these demands for chemical engineering education. These implications include definitions of sustainability criteria for the sector and the need for transparent reporting under the Triple Bottom Line approach. The response of the education system to the sustainability agenda over the years and a number of strategies to incorporate it into courses are described. The important role of chemical (or more generally, process) engineers in delivering sustainable solutions is emphasised but this also suggests that anew way of thinking about the discipline is required. Indeed, this paper argues that the demand for a sustainable chemicalmanufacturing sector could bring about the next paradigm shift in the discipline which has been predicted for some time

    Another step closer to measuring the ghosts in the nursery: preliminary validation of the Trauma Reflective Functioning Scale

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    The aim of this study was to examine preliminary evidence of the validity of the Trauma Reflective Functioning Scale and to investigate reflective functioning (RF) and attachment in pregnant women with histories of trauma, with a particular focus on the capacity to mentalize regarding trauma and its implications for adaptation to pregnancy and couple functioning. The Adult Attachment Interview was used to assess attachment, unresolved trauma and mentalization (measured as RF) regarding relationships with attachment figures (RF-G) and trauma (RF-T) in 100 pregnant women with histories of abuse and neglect. The majority (63%) of women had insecure attachment states of mind and approximately half were unresolved regarding trauma. Furthermore, the majority of women manifested deficits specific to RF-T. Their RF-T was significantly lower than their RF-G; the findings indicate that women with histories of childhood abuse and neglect do not manifest a generic inhibition of reflectiveness, but a collapse of mentalization specific to trauma. Low RF-T, indicative of difficulty in considering traumatic experiences in mental state terms, was associated with difficulty in investment in the pregnancy and lack of positive feelings about the baby and motherhood. In addition, low RF-T was also associated with difficulties in intimate relationships. Results of a regression analysis with RF indicated that RF-T was the best predictor of investment in pregnancy and couple functioning. In sum, the study provides preliminary evidence that RF-T can be reliably measured and is a valid construct that has potential usefulness for research and clinical practice. It highlights the importance of mentalization specifically about trauma and suggests that it is not the experience of trauma per se, but the absence of mentalization regarding trauma that is associated with difficulties in close relationships and in making the transition to parenthood

    High frequency sound waves in vitreous silica

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    We report a molecular dynamics simulation study of the sound waves in vitreous silica in the mesoscopic exchanged momentum range. The calculated dynamical structure factors are in quantitative agreement with recent experimental inelastic neutron and x-ray scattering data. The analysis of the longitudinal and transverse current spectra allows to discriminate between opposite interpretations of the existing experimental data in favour of the propagating nature of the high frequency sound waves.Comment: 4 pages, Revtex, 4 ps figures; to be published in Phys. Rev. Lett., February 198

    Probing Noncommutativity with Inflationary Gravitational Waves

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    In this paper we study the behaviour of gravitational wave background (GWB) generated during inflation in the environment of the noncommutative field approach. From this approach we derive out one additive term, and then we find that the dispersion relation of the gravitational wave would be modified and the primordial gravitational wave would obtain an effective mass. Therefore it breaks lorentz symmetry in local. Moreover, this additive term would a little raise up the energy spectrum of GWB in low frequency and then greatly suppress the spectrum at even lower energy scale of which the wave length may be near the current horizon. Therefore, a sharp peak is formed on the energy spectrum in the range of low frequencies. This peak should be a key criterion to detect the possible existence of noncommutativity of space-time in the background of our universe and a critical test for breaking lorentz symmetry in local field theory. Adding all possible effects on the evolution of GWB, we give some new information of the tensor power spectrum and its energy spectrum which may be probed in the future cosmological observations.Comment: 10 pages, 4 figures, improved versio

    From parliamentary pay to party funding: the acceptability of informal institutions in advanced democracies

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    While direct state funding of political parties has been a prominent theme in cross-national research over the last decade, we still know little about party strategies to access state resources that are not explicitly earmarked for partisan usage. This paper looks at one widespread but often overlooked informal party practice: the ‘taxing’ of MP salaries, i.e., the regular transfer of fixed salary shares to party coffers. Building on notions of informal institutions developed in work on new democracies, our theoretical approach specifies factors that shape the acceptability of this legally non-enforceable intra-organisational practice. It is tested through a selection model applied to a unique data set covering 124 parties across 19 advanced democracies. Controlling for a range of party- and institutional-level variables, we find that the presence of a taxing rule and the collection of demanding tax shares are more common in leftist parties (high internal acceptability) and in systems in which the penetration of state institutions by political parties is intense (high external acceptability)

    On the Importance of Atomic Fluctuations, Protein Flexibility, and Solvent in Ion Permeation

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    Proteins, including ion channels, often are described in terms of some average structure and pictured as rigid entities immersed in a featureless solvent continuum. This simplified view, which provides for a convenient representation of the protein's overall structure, incurs the risk of deemphasizing important features underlying protein function, such as thermal fluctuations in the atom positions and the discreteness of the solvent molecules. These factors become particularly important in the case of ion movement through narrow pores, where the magnitude of the thermal fluctuations may be comparable to the ion pore atom separations, such that the strength of the ion channel interactions may vary dramatically as a function of the instantaneous configuration of the ion and the surrounding protein and pore water. Descriptions of ion permeation through narrow pores, which employ static protein structures and a macroscopic continuum dielectric solvent, thus face fundamental difficulties. We illustrate this using simple model calculations based on the gramicidin A and KcsA potassium channels, which show that thermal atomic fluctuations lead to energy profiles that vary by tens of kcal/mol. Consequently, within the framework of a rigid pore model, ion-channel energetics is extremely sensitive to the choice of experimental structure and how the space-dependent dielectric constant is assigned. Given these observations, the significance of any description based on a rigid structure appears limited. Creating a conducting channel model from one single structure requires substantial and arbitrary engineering of the model parameters, making it difficult for such approaches to contribute to our understanding of ion permeation at a microscopic level

    Interacting entropy-corrected holographic dark energy with apparent horizon as an infrared cutoff

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    In this work we consider the entropy-corrected version of interacting holographic dark energy (HDE), in the non-flat universe enclosed by apparent horizon. Two corrections of entropy so-called logarithmic 'LEC' and power-law 'PLEC' in HDE model with apparent horizon as an IR-cutoff are studied. The ratio of dark matter to dark energy densities uu, equation of state parameter wDw_D and deceleration parameter qq are obtained. We show that the cosmic coincidence is satisfied for both interacting models. By studying the effect of interaction in EoS parameter, we see that the phantom divide may be crossed and also find that the interacting models can drive an acceleration expansion at the present and future, while in non-interacting case, this expansion can happen only at the early time. The graphs of deceleration parameter for interacting models, show that the present acceleration expansion is preceded by a sufficiently long period deceleration at past. Moreover, the thermodynamical interpretation of interaction between LECHDE and dark matter is described. We obtain a relation between the interaction term of dark components and thermal fluctuation in a non-flat universe, bounded by the apparent horizon. In limiting case, for ordinary HDE, the relation of interaction term versus thermal fluctuation is also calculated.Comment: 20 pages, 8 figures, figures changed, some Ref. is added, changed some sentences, accepted by General relativity and gravitation (GERG
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