988 research outputs found
Divergent gold-catalysed reactions of cyclopropenylmethyl sulfonamides with tethered heteroaromatics
Cyclopropenylmethyl sulfonamides with tethered heteroaromatics have been demonstrated to undergo divergent gold-catalysed cyclisation reactions. A formal dearomative (4+3) cycloaddition takes place with furan-tethered substrates, yielding densely functionalised 5,7-fused heterocycles related to the bioactive curcusone natural products. Indole-tethered substrates display divergent reactivity giving biologically important tetrahydro-β-carbolines via a Friedel-Crafts mechanism
Black hole scaling relations of active and quiescent galaxies: Addressing selection effects and constraining virial factors
Local samples of quiescent galaxies with dynamically measured black hole
masses (Mbh) may suffer from an angular resolution-related selection effect,
which could bias the observed scaling relations between Mbh and host galaxy
properties away from the intrinsic relations. In particular, previous work has
shown that the observed Mbh-Mstar (stellar mass) relation is more strongly
biased than the Mbh-sigma (velocity dispersion) relation. Local samples of
active galactic nuclei (AGN) do not suffer from this selection effect, as in
these samples Mbh is estimated from megamasers and/or reverberation
mapping-based techniques. With the exception of megamasers, Mbh-estimates in
these AGN samples are proportional to a virial coefficient fvir. Direct
modelling of the broad line region suggests that fvir~3.5. However, this
results in a Mbh-Mstar relation for AGN which lies below and is steeper than
the one observed for quiescent black hole samples. A similar though milder
trend is seen for the Mbh-sigma relation. Matching the high-mass end of the
Mbh-Mstar and Mbh-sigma relations observed in quiescent samples requires
fvir~15 and fvir~7, respectively. On the other hand, fvir~3.5 yields Mbh-sigma
and Mbh-Mstar relations for AGN which are remarkably consistent with the
expected `intrinsic' correlations for quiescent samples (i.e., once account has
been made of the angular resolution-related selection effect), providing
additional evidence that the sample of local quiescent black holes is biased.
We also show that, as is the case for quiescent black holes, the Mbh-Mstar
scaling relation of AGN is driven by velocity dispersion, thus providing
additional key constraints to black hole-galaxy co-evolution models.Comment: 15 pages, 5 Figures. MNRAS, accepte
Temporal shaping of single photons by engineering exciton dynamics in a single quantum dot
The majority of photonic quantum information technologies rely on single photons that have high purity and indistinguishability. Although solid-state quantum emitters can serve such single photons on demand, their asymmetric temporal and spatial mode profiles limit the optimal efficiency and fidelity of quantum interaction. Here, we demonstrate single-photon pulses at a telecom wavelength with a Gaussian-like temporal mode profile from a cavity-coupled single quantum dot. Engineering the exciton dynamics via multi-exciton cascade recombination and cavity detuning enables us to modify the rise and decay dynamics of single excitons. Furthermore, the cascade recombination process temporally retards the single-exciton emission from the background emission, leading to possible purification of single photons at high excitation power. In addition, coupling quantum dots into a low Q cavity mode leads to a Gaussian-like spatial mode profile, which brings a high collection efficiency. This approach paves the way for producing single photons with an optimized temporal and spatial waveform
MOLLI T1 mapping versus T2 W-SPAIR at 3T : myocardial area at risk measurements and the influence of microvascular obstruction
Funding Information: This study was supported by a Medical Research Council (UK) grant, as a sub-study of Nitrites in Acute Myocardial Infarction, NCT01388504.Peer reviewe
30 days wild: development and evaluation of a large-scale nature engagement campaign to improve well-being
There is a need to increase people’s engagement with and connection to nature, both for human well-being and the conservation of nature itself. In order to suggest ways for people to engage with nature and create a wider social context to normalise nature engagement, The Wildlife Trusts developed a mass engagement campaign, 30 Days Wild. The campaign asked people to engage with nature every day for a month. 12,400 people signed up for 30 Days Wild via an online sign-up with an estimated 18,500 taking part overall, resulting in an estimated 300,000 engagements with nature by participants. Samples of those taking part were found to have sustained increases in happiness, health, connection to nature and pro-nature behaviours. With the improvement in health being predicted by the improvement in happiness, this relationship was mediated by the change in connection to nature
Educating novice practitioners to detect elder financial abuse: A randomised controlled trial
© 2014 Harries et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.This article has been made available through the Brunel Open Access Publishing Fund.Background - Health and social care professionals are well positioned to identify and intervene in cases of elder financial abuse. An evidence-based educational intervention was developed to advance practitioners’ decision-making in this domain. The objective was to test the effectiveness of a decision-training educational intervention on novices’ ability to detect elder financial abuse. The research was funded by an E.S.R.C. grant reference RES-189-25-0334.
Methods - A parallel-group, randomised controlled trial was conducted using a judgement analysis approach. Each participant used the World Wide Web to judge case sets at pre-test and post-test. The intervention group was provided with training after pre-test testing, whereas the control group were purely given instructions to continue with the task. 154 pre-registration health and social care practitioners were randomly allocated to intervention (n78) or control (n76). The intervention comprised of written and graphical descriptions of an expert consensus standard explaining how case information should be used to identify elder financial abuse. Participants’ ratings of certainty of abuse occurring (detection) were correlated with the experts’ ratings of the same cases at both stages of testing.
Results - At pre-test, no differences were found between control and intervention on rating capacity. Comparison of mean scores for the control and intervention group at pre-test compared to immediate post-test, showed a statistically significant result. The intervention was shown to have had a positive moderate effect; at immediate post-test, the intervention group’s ratings had become more similar to those of the experts, whereas the control’s capacity did not improve. The results of this study indicate that the decision-training intervention had a positive effect on detection ability.
Conclusions - This freely available, web-based decision-training aid is an effective evidence-based educational resource. Health and social care professionals can use the resource to enhance their ability to detect elder financial abuse. It has been embedded in a web resource at http://www.elderfinancialabuse.co.uk.ESR
BioStar: An Online Question & Answer Resource for the Bioinformatics Community
Parnell, Laurence D. et al.Although the era of big data has produced many bioinformatics tools and databases, using them effectively often requires specialized knowledge. Many groups lack bioinformatics expertise, and frequently find that software documentation is inadequate while local colleagues may be overburdened or unfamiliar with specific applications. Too often, such problems create data analysis bottlenecks that hinder the progress of biological research. In order to help address this deficiency, we present BioStar, a forum based on the Stack Exchange platform where experts and those seeking solutions to problems of computational biology exchange ideas. The main strengths of BioStar are its large and active group of knowledgeable users, rapid response times, clear organization of questions and responses that limit discussion to the topic at hand, and ranking of questions and answers that help identify their usefulness. These rankings, based on community votes, also contribute to a reputation score for each user, which serves to keep expert contributors engaged. The BioStar community has helped to answer over 2,300 questions from over 1,400 users (as of June 10, 2011), and has played a critical role in enabling and expediting many research projects. BioStar can be accessed at http://www.biostars.org/.This work was partially supported by NSF grants MCB-0618402 and CCF-0643529 (CAREER), NIH grants 1R55AI065507 – 01A2 and 1 R01 GM083113-01, NIH/NCRR grant number UL1RR033184, and FPI fellowship SAF-2007-63171/BES-2009-017731 from the Ministerio de Educación y Ciencia, Spain. These funders had no role in the design of BioStar, decision to publish, or preparation of the manuscript.Peer reviewe
Plug???and???Play Single???Photon Devices with Efficient Fiber???Quantum Dot Interface
Incorporating solid-state quantum emitters into optical fiber networks enables the long-distance transmission of quantum information and the remote connection of distributed quantum nodes. However, interfacing quantum emitters with fiber optics encounters several challenges, including low coupling efficiency and delicate configuration. In this study, a highly efficient fiber-interfacing photonic device that directly launches single photons from quantum dots into a standard FC/PC-connectorized single-mode fiber is demonstrated. Optimally designed photonic structures based on hole gratings produce an ultra-narrow directional beam that matches the small numerical aperture of a single-mode fiber. A pick-and-place technique precisely integrates a single miniaturized device into the core of the fiber. This approach realizes a plug-and-play single-photon device that does not require optical alignment and thus guarantees long-term stability. The results represent a major step toward practical and reliable transmission of quantum light across a fiber network
- …