770 research outputs found

    Edwards-Wilkinson surface over a spherical substrate: 1/f1/f noise in the height fluctuations

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    We study the steady state fluctuations of an Edwards-Wilkinson type surface with the substrate taken to be a sphere. We show that the height fluctuations on circles at a given latitude has the effective action of a perfect Gaussian 1/f1/f noise, just as in the case of fixed radius circles on an infinite planar substrate. The effective surface tension, which is the overall coefficient of the action, does not depend on the latitude angle of the circles.Comment: 6 page

    Redox-switchable siderophore anchor enables reversible artificial metalloenzyme assembly

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    Artificial metalloenzymes that contain protein-anchored synthetic catalysts are attracting increasing interest. An exciting, but still unrealized advantage of non-covalent anchoring is its potential for reversibility and thus component recycling. Here we present a siderophore–protein combination that enables strong but redox-reversible catalyst anchoring, as exemplified by an artificial transfer hydrogenase (ATHase). By linking the iron(iii)-binding siderophore azotochelin to an iridium-containing imine-reduction catalyst that produces racemic product in the absence of the protein CeuE, but a reproducible enantiomeric excess if protein bound, the assembly and reductively triggered disassembly of the ATHase was achieved. The crystal structure of the ATHase identified the residues involved in high-affinity binding and enantioselectivity. While in the presence of iron(iii), the azotochelin-based anchor binds CeuE with high affinity, and the reduction of the coordinated iron(iii) to iron(ii) triggers its dissociation from the protein. Thus, the assembly of the artificial enzyme can be controlled via the iron oxidation state

    C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.

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    STUDY DESIGN: A multicenter, retrospective review of C5 palsy after cervical spine surgery. OBJECTIVE: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery. METHODS: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ(2) tests or Fisher exact tests for categorical variables. RESULTS: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%). CONCLUSION: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date

    Data sharing and ontology use among agricultural genetics, genomics, and breeding databases and resources of the AgBioData Consortium

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    Over the last several decades, there has been rapid growth in the number and scope of agricultural genetics, genomics and breeding (GGB) databases and resources. The AgBioData Consortium (https://www.agbiodata.org/) currently represents 44 databases and resources covering model or crop plant and animal GGB data, ontologies, pathways, genetic variation and breeding platforms (referred to as 'databases' throughout). One of the goals of the Consortium is to facilitate FAIR (Findable, Accessible, Interoperable, and Reusable) data management and the integration of datasets which requires data sharing, along with structured vocabularies and/or ontologies. Two AgBioData working groups, focused on Data Sharing and Ontologies, conducted a survey to assess the status and future needs of the members in those areas. A total of 33 researchers responded to the survey, representing 37 databases. Results suggest that data sharing practices by AgBioData databases are in a healthy state, but it is not clear whether this is true for all metadata and data types across all databases; and that ontology use has not substantially changed since a similar survey was conducted in 2017. We recommend 1) providing training for database personnel in specific data sharing techniques, as well as in ontology use; 2) further study on what metadata is shared, and how well it is shared among databases; 3) promoting an understanding of data sharing and ontologies in the stakeholder community; 4) improving data sharing and ontologies for specific phenotypic data types and formats; and 5) lowering specific barriers to data sharing and ontology use, by identifying sustainability solutions, and the identification, promotion, or development of data standards. Combined, these improvements are likely to help AgBioData databases increase development efforts towards improved ontology use, and data sharing via programmatic means.Comment: 17 pages, 8 figure

    Know Thyself: Behavioral Evidence for a Structural Representation of the Human Body

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    Background: Representing one's own body is often viewed as a basic form of self-awareness. However, little is known about structural representations of the body in the brain.Methods and Findings: We developed an inter-manual version of the classical "in-between'' finger gnosis task: participants judged whether the number of untouched fingers between two touched fingers was the same on both hands, or different. We thereby dissociated structural knowledge about fingers, specifying their order and relative position within a hand, from tactile sensory codes. Judgments following stimulation on homologous fingers were consistently more accurate than trials with no or partial homology. Further experiments showed that structural representations are more enduring than purely sensory codes, are used even when number of fingers is irrelevant to the task, and moreover involve an allocentric representation of finger order, independent of hand posture.Conclusions: Our results suggest the existence of an allocentric representation of body structure at higher stages of the somatosensory processing pathway, in addition to primary sensory representation

    Adjacent single-stranded regions mediate processing of tRNA precursors by RNase E direct entry

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    The RNase E family is renowned for being central to the processing and decay of all types of RNA in many species of bacteria, as well as providing the first examples of endonucleases that can recognize 50 -monophosphorylated ends thereby increasing the efficiency of cleavage. However, there is increasing evidence that some transcripts can be cleaved efficiently by Escherichia coli RNase E via direct entry, i.e. in the absence of the recognition of a 50 -monophosphorylated end. Here, we provide biochemical evidence that direct entry is central to the processing of transfer RNA (tRNA) in E. coli, one of the core functions of RNase E, and show that it is mediated by specific unpaired regions that are adjacent, but not contiguous to segments cleaved by RNase E. In addition, we find that direct entry at a site on the 50 side of a tRNA precursor triggers a series of 50 -monophosphate-dependent cleavages. Consistent with a major role for direct entry in tRNA processing, we provide additional evidence that a 50 -monophosphate is not required to activate the catalysis step in cleavage. Other examples of tRNA precursors processed via direct entry are also provided. Thus, it appears increasingly that direct entry by RNase E has a major role in bacterial RNA metabolism

    Topography-derived wetness indices are associated with household-level malaria risk in two communities in the western Kenyan highlands

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    <p>Abstract</p> <p>Background</p> <p>Transmission of <it>Plasmodium falciparum </it>generally decreases with increasing elevation, in part because lower temperature slows the development of both parasites and mosquitoes. However, other aspects of the terrain, such as the shape of the land, may affect habitat suitability for <it>Anopheles </it>breeding and thus risk of malaria transmission. Understanding these local topographic effects may permit prediction of regions at high risk of malaria within the highlands at small spatial scales.</p> <p>Methods</p> <p>Hydrologic modelling techniques were adapted to predict the flow of water across the landscape surrounding households in two communities in the western Kenyan highlands. These surface analyses were used to generate indices describing predicted water accumulation in regions surrounding the study area. Households with and without malaria were compared for their proximity to regions of high and low predicted wetness. Predicted wetness and elevation variables were entered into bivariate and multivariate regression models to examine whether significant associations with malaria were observable at small spatial scales.</p> <p>Results</p> <p>On average, malaria case households (n = 423) were located 280 m closer to regions with very high wetness indices than non-malaria "control" households (n = 895) (t = 10.35, p < 0.0001). Distance to high wetness indices remained an independent predictor of risk after controlling for household elevation in multivariate regression (OR = 0.93 [95% confidence interval = 0.89–0.96] for a 100 m increase in distance). For every 10 m increase in household elevation, there was a 12% decrease in the odds of the house having a malaria case (OR = 0.88 [0.85–0.90]). However, after controlling for distance to regions of high predicted wetness and the community in which the house was located, this reduction in malaria risk was not statistically significant (OR = 0.98 [0.94–1.03]).</p> <p>Conclusion</p> <p>Proximity to terrain with high predicted water accumulation was significantly and consistently associated with increased household-level malaria incidence, even at small spatial scales with little variation in elevation variables. These results suggest that high wetness indices are not merely proxies for valley bottoms, and hydrologic flow models may prove valuable for predicting areas of high malaria risk in highland regions. Application in areas where malaria surveillance is limited could identify households at higher risk and help focus interventions.</p

    KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System

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    We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of 1.586-0.040+0.039 RJ. We set an upper limit on the planetary mass of at confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin-orbit misalignment of λ = -5.6-1.91.7. The star has Teff = 7598-8481 K, Mz.ast; = 1.458-0.028+0.029 M⊙, Rz.ast; = 1.638 ± 0.034 R⊙ and v sin I∗ = 146 km s-1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal poor and α-enhanced, with [Fe/H] = -405-0.033+0.032 and [α/Fe] = 0.145 ± 0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.″2 and with a combined contrast of ΔKs = 6.39 ± 0.06 with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of ∼0.12 M⊙, a projected mutual separation of ∼20 au, and a projected separation of ∼500 au from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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