7,394 research outputs found
Leading for Learning: Reflective Tools for School and District Leaders
Provides reflective ideas and tools for educators to enhance leadership in learning. Includes key ideas, real examples, and reflective questions that leaders can use can use to assess their organizations, enact strategic plans, and teach colleagues
Lessons from LIMK1 enzymology and their impact on inhibitor design
LIM domain kinase 1 (LIMK1) is a key regulator of actin dynamics. It is thereby a potential therapeutic target for the prevention of fragile X syndrome and amyotrophic lateral sclerosis. Herein, we use X-ray crystallography and activity assays to describe how LIMK1 accomplishes substrate specificity, to suggest a unique ‘rock-and-poke’ mechanism of catalysis and to explore the regulation of the kinase by activation loop phosphorylation. Based on these findings, a differential scanning fluorimetry assay and a RapidFire mass spectrometry activity assay were established, leading to the discovery and confirmation of a set of small-molecule LIMK1 inhibitors. Interestingly, several of the inhibitors were inactive towards the closely related isoform LIMK2. Finally, crystal structures of the LIMK1 kinase domain in complex with inhibitors (PF-477736 and staurosporine, respectively) are presented, providing insights into LIMK1 plasticity upon inhibitor binding
Optimised patient information materials and recruitment to a study of behavioural activation in older adults : an embedded study within a trial [version 1; peer review: awaiting peer review]
YesPrinted participant information about randomised controlled trials is often long, technical and difficult to navigate. Improving information materials is possible through optimisation and user-testing, and may impact on participant understanding and rates of recruitment. Methods: A study within a trial (SWAT) was undertaken within the CASPER trial. Potential CASPER participants were randomised to receive either the standard trial information or revised information that had been optimised through information design and user testing. Results: A total of 11,531 patients were randomised in the SWAT. Rates of recruitment to the CASPER trial were 2.0% in the optimised information group and 1.9% in the standard information group (odds ratio 1.027; 95% CI 0.79 to 1.33; p=0.202). Conclusions: Participant information that had been optimised through information design and user testing did not result in any change to rate of recruitment to the host trial. Registration: ISRCTN ID ISRCTN02202951; registered on 3 June 2009.UK National Institute of Health Research Health Technology Assessment Programme (project number 08/19/04)This article is included in the Studies Within A Trial (SWAT) collection (https://f1000research.com/collections/swat
Influence of Complex Exciton-Phonon Coupling on Optical Absorption and Energy Transfer of Quantum Aggregates
We present a theory that efficiently describes the quantum dynamics of an
electronic excitation that is coupled to a continuous, highly structured phonon
environment. Based on a stochastic approach to non-Markovian open quantum
systems, we develop a dynamical framework that allows us to handle realistic
systems where a fully quantum treatment is desired yet the usual approximation
schemes fail. The capability of the method is demonstrated by calculating
spectra and energy transfer dynamics of mesoscopic molecular aggregates,
elucidating the transition from fully coherent to incoherent transfer
Ship incident risk in the areas of Tubbataha and Banc d’Arguin: A case for designation as Particular Sensitive Sea Area?
Since the early 1990's, the International Maritime Organization (IMO) has designated fourteen sea areas as Particular Sensitive Sea Areas (PSSA) that enjoy special protection because of their various important attributes and vulnerability to potential harm by increasing shipping activities. The United Nations Educational, Scientific and Cultural Organization (UNESCO) has identified two possible sites for possible designation as PSSA under IMO: the Banc d'Arguin National Park (Mauritania) and the Tubbataha Reef National Park (Philippines). This article presents an integrated framework for the estimation of total risk exposure due to shipping activities and various risk measures for ships trading in the areas of interest. Using a unique and comprehensive combination of data, we test whether ship specific risk increased over time. The results confirm an increase in the considered risk measures of ships trading through or nearby West Africa (Banc d’Arguin) and South-East Asia (Tubbataha) in general and also close to both regions and therefore support the recommendation for an increased level of protection
Testing Radiatively-Inefficient Accretion Flow Theory: an XMM-Newton Observation of NGC 3998
We present the results of a 10 ks XMM-Newton observation of NGC 3998, a
``type-I'' LINER galaxy. Our goal is to test the extent to which
radiatively-inefficient accretion flow (RIAF) models and/or scaled-down AGN
models are consistent with the observed properties of NGC 3998. The upper-limit
for narrow Fe-K emission derived from a combined fit of the XMM-Newton and
BeppoSAX spectra is 25 eV, which is one of the strictest limits to date for any
AGN. This significantly rules out Fe-K emission as is expected to be observed
in typical Seyfert 1 galaxies. The lack of any reflection features suggests
that any optically-thick, geometrically-thin accretion disk must be truncated,
probably at a radius of order 100-300 R_s. RIAF models fit the UV to X-ray
spectral energy distribution of NGC 3998 reasonably well. In these models the
mid-IR flux also constrains the emission from any outer thin disk component
that might be present. The UV to X-ray SED is also consistent with a
Comptonized thin disk with a very low accretion rate, in which case the lack of
Fe-K emission may be due to an ionized accretion disk. Accretion models in
general do not account for the observed radio flux of NGC 3998, and the radio
flux may be due to a jet. Recent jet models may also be consistent with the
nuclear fluxes of NGC 3998 in general, including the X-ray, optical/UV and
mid-IR bands. We also derive nuclear fluxes using archival HST WFPC2 data to
constrain the SED of NGC 3998. We discuss a possible OM U band and USNO-B
detection of the NGC 3998 ULX.Comment: Accepted for publication in ApJ. 13 pages and 5 figures formatted
with emulateapj. Version with black-and-white only plots available at
http://www.pha.jhu.edu/~ptak/paper
Cavitation inception of a van der Waals fluid at a sack-wall obstacle
Cavitation in a liquid moving past a constraint is numerically investigated
by means of a free-energy lattice Boltzmann simulation based on the van der
Waals equation of state. The fluid is streamed past an obstacle and, depending
on the pressure drop between inlet and outlet, vapor formation underneath the
corner of the sack-wall is observed. The circumstances of cavitation formation
are investigated and it is found that the local bulk pressure and mean stress
are insufficient to explain the phenomenon. Results obtained in this study
strongly suggest that the viscous stress, interfacial contributions to the
local pressure, and the Laplace pressure are relevant to the opening of a vapor
cavity. This can be described by a generalization of Joseph's criterion that
includes these contributions. A macroscopic investigation measuring mass flow
rate behavior and discharge coefficient was also performed. As theoretically
predicted, mass flow rate increases linearly with the square root of the
pressure drop. However, when cavitation occurs, the mass flow growth rate is
reduced and eventually it collapses into a choked flow state. In the cavitating
regime, as theoretically predicted and experimentally verified, the discharge
coefficient grows with the Nurick cavitation number
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