3,690 research outputs found

    Chitin degradation by Synechococcus WH7803

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    Chitin is an abundant, carbon-rich polymer in the marine environment. Chitinase activity has been detected in spent media of Synechococcus WH7803 cultures—yet it was unclear which specific enzymes were involved. Here we delivered a CRISPR tool into the cells via electroporation to generate loss-of-function mutants of putative candidates and identified ChiA as the enzyme required for the activity detected in the wild type

    The action for higher spin black holes in three dimensions

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    In the context of (2+1)--dimensional Chern-Simons SL(N,R)\times SL(N,R) gauge fields and spin N black holes we compute the on-shell action and show that it generates sensible and consistent thermodynamics. In particular, the Chern-Simons action solves the integrability conditions recently considered in the literature.Comment: Paper shortened and generalized. Main results unchanged. 25 pages, Latex, no figure

    Stringy effects in black hole decay

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    We compute the low energy decay rates of near-extremal three(four) charge black holes in five(four) dimensional N=4 string theory to sub-leading order in the large charge approximation. This involves studying stringy corrections to scattering amplitudes of a scalar field off a black hole. We adapt and use recently developed techniques to compute such amplitudes as near-horizon quantities. We then compare this with the corresponding calculation in the microscopic configuration carrying the same charges as the black hole. We find perfect agreement between the microscopic and macroscopic calculations; in the cases we study, the zero energy limit of the scattering cross section is equal to four times the Wald entropy of the black hole.Comment: 32 page

    Cardy and Kerr

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    The Kerr/CFT correspondence employs the Cardy formula to compute the entropy of the left moving CFT states. This computation, which correctly reproduces the Bekenstein--Hawking entropy of the four-dimensional extremal Kerr black hole, is performed in a regime where the temperature is of order unity rather than in a high-temperature regime. We show that the comparison of the entropy of the extreme Kerr black hole and the entropy in the CFT can be understood within the Cardy regime by considering a D0-D6 system with the same entropic properties.Comment: 20 pages; LaTeX; JHEP format; v.2 references added, v.3 Section 4 adde

    A critical analysis of building sustainability assessment methods for healthcare buildings

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    The healthcare building project contains different aspects from the most common projects. Designing a healthcare environment is based on a number of criteria related to the satisfaction and well-being of the professional working teams, patients and administrators. Mostly due to various design requirements, these buildings are rarely designed and operated in a sustainable way. Therefore, the sustainable development is a concept whose importance has grown significantly in the last decade in this sector. The worldwide economic crisis reinforces the growing environmental concerns as well as raising awareness among people to a necessary and inevitable shift in the values of their society. To support sustainable building design, several building sustainability assessment (BSA) methods are being developed worldwide. Since healthcare buildings are rather complex systems than other buildings, so specific methods were developed for them. These methods are aimed to support decision-making towards the introduction of the best sustainability practices during the design and operation phases of a healthcare environment. However, the comparison between the results of different methods is difficult, if not impossible, since they address different environmental, societal and economic criteria, and they emphasize different phases of the life cycle. Therefore, the aim of this study was to clarify the differences between the main BSA methods for healthcare buildings by analysing and categorizing them. Furthermore, the benefits of these methods in promoting a more sustainable environment will be analysed, and the current situation of them within the context of standardization of the concept sustainable construction will be discussed.The authors acknowledge the Portuguese Foundation for Science and Technology and POPH/FSE for the financial support for this study under the Reference SFRH/BD/77959/2011

    Seedling emergence and establishment of Pinus sylvestris in the Mongolian forest-steppe ecotone

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    Syftet med studien Ă€r att undersöka och beskriva pedagogers uppfattningar av hur de skapar delaktighet och inflytande, i en kommuns förskoleverksamhet och organisation.Mina frĂ„gestĂ€llningar Ă€r hur pedagogerna beskriver sina möjligheter och hinder för att fĂ„ och skapa delaktighet och inflytande, samt vilka inre och yttre faktorer som finns som pĂ„verkar möjligheten för delaktighet och inflytande.För att undersöka detta har jag valt en kvalitativ forskningsansats. Jag har genomfört semistrukturerade intervjuer med sju pedagoger. Det empiriska materialet har bearbetats kvalitativt i en empirinĂ€ra ansats.I resultatet sĂ„g jag att ett större fokus pĂ„ processkvaliteten behöver lĂ€ggas och medvetenheten behöver ökas, kring den pedagogiska dokumentationens betydelse.Sammanfattningsvis behöver den undersökta kommunens förskolor en gemensam samsyn i hela systemet i ett förstĂ„elsebaserat och tolkande perspektiv som gynnar en lĂ„ngsiktig och hĂ„llbar utveckling.Participation and influence in the preschool, a study with teachers in one municipality.The purpose of this study is to explore and describe teacher’s perceptions of how they create participation and influence, in a municipalityÂŽs preschool and organization.My questions are how teachers describe their opportunities and barriers to get and create participation and influence, and what internal and external factors that affecting the ability of participation and influence.To examine this, I have chosen a qualitative research approach. I have conducted semi structured interviews, with seven teachers. The empirical data have been processed in a qualitative empirical closely approach.In the result, I found that a greater focus on process quality needs to be added and awareness needs to be increased, on the pedagogic documentations significances.In conclusion, needs the municipal preschools, which have been examined, get a common consensus of the entire system in a understanding based and interpretive perspective, that support a long term and sustainable development

    The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis

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    Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P = 1.34×10<sup>−8</sup>, OR = 1.22, CI 95% = 1.14–1.30; rs2004640: P = 4.60×10<sup>−7</sup>, OR = 0.84, CI 95% = 0.78–0.90; rs10488631: P = 7.53×10<sup>−20</sup>, OR = 1.63, CI 95% = 1.47–1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P = 9.04×10<sup>−22</sup>, OR = 1.75, CI 95% = 1.56–1.97) better explained the observed association (likelihood P-value = 1.48×10<sup>−4</sup>), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific

    Matrix Norms, BPS Bounds and Marginal Stability in N=8 Supergravity

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    We study the conditions of marginal stability for two-center extremal black holes in N-extended supergravity in four dimensions, with particular emphasis on the N=8 case. This is achieved by exploiting triangle inequalities satisfied by matrix norms. Using different norms and relative bounds among them, we establish the existence of marginal stability and split attractor flows both for BPS and some non-BPS solutions. Our results are in agreement with previous analysis based on explicit construction of multi-center solutions.Comment: 1+15 pages; v2: some new formulas added and misprints corrected; v3: typos fixed, various refinements, Sec. 2.4 rewritten; to appear on JHE

    The Escherichia coli transcriptome mostly consists of independently regulated modules

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    Underlying cellular responses is a transcriptional regulatory network (TRN) that modulates gene expression. A useful description of the TRN would decompose the transcriptome into targeted effects of individual transcriptional regulators. Here, we apply unsupervised machine learning to a diverse compendium of over 250 high-quality Escherichia coli RNA-seq datasets to identify 92 statistically independent signals that modulate the expression of specific gene sets. We show that 61 of these transcriptomic signals represent the effects of currently characterized transcriptional regulators. Condition-specific activation of signals is validated by exposure of E. coli to new environmental conditions. The resulting decomposition of the transcriptome provides: a mechanistic, systems-level, network-based explanation of responses to environmental and genetic perturbations; a guide to gene and regulator function discovery; and a basis for characterizing transcriptomic differences in multiple strains. Taken together, our results show that signal summation describes the composition of a model prokaryotic transcriptome
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