13,341 research outputs found
The United Kingdom Ministry of Defence – the Case for Followership as a key Element of Leadership Development
Published in Strategic Management Quarterly (2015) Vol 3 Issue 4Using the Kelley (1992) Followership Style instrument this study explores the role and perceptions of Followership within the UK Ministry of Defence. In particular, within the Armed Services and the Civil Service it was apparent from the literature that only the RAF formally recognised the role of Followership within their Leadership staff development programmes, hence the research aimed to see whether this was reflected in self-perceptions of Followership Style and the extent to which it is applied within the organisation. The analysis concluded that the analysed sample (298 responses) produced an atypical profile compared to other studies that have used the instrument. The RAF showed statistically significant higher scores than the other Armed Services or the Civil Servants and scores increased with Rank/Grade. The analysis also highlighted that the individuals seemed not to be recognised as good Followers by their leaders, they appeared not to recognise their reports as good Followers and in all cases the organisation seemed not to recognise their value. These aspects provide scope for further research to better understand the organisational culture, processes and practices that appear to act as a barrier to the extraction of the benefits of having good Followers even in an area where Star Followers dominate
Assembly, Structure, and Reactivity of Cu\u3csub\u3e4\u3c/sub\u3eS and Cu\u3csub\u3e3\u3c/sub\u3eS Models for the Nitrous Oxide Reductase Active Site, Cu\u3csub\u3eZ\u3c/sub\u3e*
Bridging diphosphine ligands were used to facilitate the assembly of copper clusters with single sulfur atom bridges that model the structure of the CuZ* active site of nitrous oxide reductase. Using bis(diphenylphosphino)amine (dppa), a [CuI4(μ4-S)] cluster with N–H hydrogen bond donors in the secondary coordination sphere was assembled. Solvent and anion guests were found docking to the N–H sites in the solid state and in the solution phase, highlighting a kinetically viable pathway for substrate introduction to the inorganic core. Using bis(dicyclohexylphosphino)methane (dcpm), a [CuI3(μ3-S)] cluster was assembled preferentially. Both complexes exhibited reversible oxidation events in their cyclic voltammograms, making them functionally relevant to the CuZ* active site that is capable of catalyzing a multielectron redox transformation, unlike the previously known [CuI4(μ4-S)] complex from Yam and co-workers supported by bis(diphenylphosphino)methane (dppm). The dppa-supported [CuI4(μ4-S)] cluster reacted with N3–, a linear triatomic substrate isoelectronic to N2O, in preference to NO2–, a bent triatomic. This [CuI4(μ4-S)] cluster also bound I–, a known inhibitor of CuZ*. Consistent with previous observations for nitrous oxide reductase, the tetracopper model complex bound the I– inhibitor much more strongly and rapidly than the substrate isoelectronic to N2O, producing unreactive μ3-iodide clusters including a [Cu3(μ3-S)(μ3-I)] complex related to the [Cu4(μ4-S)(μ2-I)] form of the inhibited enzyme
Enhancing Perceptual Attributes with Bayesian Style Generation
Deep learning has brought an unprecedented progress in computer vision and
significant advances have been made in predicting subjective properties
inherent to visual data (e.g., memorability, aesthetic quality, evoked
emotions, etc.). Recently, some research works have even proposed deep learning
approaches to modify images such as to appropriately alter these properties.
Following this research line, this paper introduces a novel deep learning
framework for synthesizing images in order to enhance a predefined perceptual
attribute. Our approach takes as input a natural image and exploits recent
models for deep style transfer and generative adversarial networks to change
its style in order to modify a specific high-level attribute. Differently from
previous works focusing on enhancing a specific property of a visual content,
we propose a general framework and demonstrate its effectiveness in two use
cases, i.e. increasing image memorability and generating scary pictures. We
evaluate the proposed approach on publicly available benchmarks, demonstrating
its advantages over state of the art methods.Comment: ACCV-201
Telluric correction in the near-infrared: Standard star or synthetic transmission?
Context. The atmospheric absorption of the Earth is an important limiting
factor for ground-based spectroscopic observations and the near-infrared and
infrared regions are the most affected. Several software packages that produce
a synthetic atmospheric transmission spectrum have been developed to correct
for the telluric absorption; these are Molecfit, TelFit, and TAPAS. Aims. Our
goal is to compare the correction achieved using these three telluric
correction packages and the division by a telluric standard star. We want to
evaluate the best method to correct near-infrared high-resolution spectra as
well as the limitations of each software package and methodology. Methods. We
applied the telluric correction methods to CRIRES archival data taken in the J
and K bands. We explored how the achieved correction level varies depending on
the atmospheric T-P profile used in the modelling, the depth of the atmospheric
lines, and the molecules creating the absorption. Results. We found that the
Molecfit and TelFit corrections lead to smaller residuals for the water lines.
The standard star method corrects best the oxygen lines. The Molecfit package
and the standard star method corrections result in global offsets always below
0.5% for all lines; the offset is similar with TelFit and TAPAS for the H2O
lines and around 1% for the O2 lines. All methods and software packages result
in a scatter between 3% and 7% inside the telluric lines. The use of a tailored
atmospheric profile for the observatory leads to a scatter two times smaller,
and the correction level improves with lower values of precipitable water
vapour. Conclusions. The synthetic transmission methods lead to an improved
correction compared to the standard star method for the water lines in the J
band with no loss of telescope time, but the oxygen lines were better corrected
by the standard star method.Comment: 18 pages, 13 figures, Accepted to A&
Statistical properties of fractures in damaged materials
We introduce a model for the dynamics of mud cracking in the limit of of
extremely thin layers. In this model the growth of fracture proceeds by
selecting the part of the material with the smallest (quenched) breaking
threshold. In addition, weakening affects the area of the sample neighbour to
the crack. Due to the simplicity of the model, it is possible to derive some
analytical results. In particular, we find that the total time to break down
the sample grows with the dimension L of the lattice as L^2 even though the
percolating cluster has a non trivial fractal dimension. Furthermore, we obtain
a formula for the mean weakening with time of the whole sample.Comment: 5 pages, 4 figures, to be published in Europhysics Letter
Quantitative multielement analysis using high energy particle bombardment
Charged particles ranging in energy from 0.8 to 4.0 MeV are used to induce resonant nuclear reactions, Coulomb excitation (gamma X-rays), and X-ray emission in both thick and thin targets. Quantitative analysis is possible for elements from Li to Pb in complex environmental samples, although the matrix can severely reduce the sensitivity. It is necessary to use a comparator technique for the gamma-rays, while for X-rays an internal standard can be used. A USGS standard rock is analyzed for a total of 28 elements. Water samples can be analyzed either by nebulizing the sample doped with Cs or Y onto a thin formvar film or by extracting the sample (with or without an internal standard) onto ion exchange resin which is pressed into a pellet
A One-Hole Cu\u3csub\u3e4\u3c/sub\u3eS Cluster with N\u3csub\u3e2\u3c/sub\u3eO Reductase Activity: A Structural and Functional Model for Cu\u3csub\u3eZ\u3c/sub\u3e
During bacterial denitrification, two-electron reduction of N2O occurs at a [Cu4(μ4-S)] catalytic site (CuZ*) embedded within the nitrous oxide reductase (N2OR) enzyme. In this Communication, an amidinate-supported [Cu4(μ4-S)] model cluster in its one-hole (S = 1/2) redox state is thoroughly characterized. Along with its two-hole redox partner and fully reduced clusters reported previously, the new species completes the two-electron redox series of [Cu4(μ4-S)] model complexes with catalytically relevant oxidation states for the first time. More importantly, N2O is reduced by the one-hole cluster to produce N2 and the two-hole cluster, thereby completing a closed cycle for N2O reduction. Not only is the title complex thus the best structural model for CuZ* to date, but it also serves as a functional CuZ* mimic
A Cu\u3csub\u3e4\u3c/sub\u3eS Model for the Nitrous Oxide Reductase Active Sites Supported Only by Nitrogen Ligands
To model the (His)7Cu4Sn (n = 1 or 2) active sites of nitrous oxide reductase, the first Cu4(μ4-S) cluster supported only by nitrogen donors has been prepared using amidinate supporting ligands. Structural, magnetic, spectroscopic, and computational characterization is reported. Electrochemical data indicates that the 2-hole model complex can be reduced reversibly to the 1-hole state and irreversibly to the fully reduced state
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Evolutionary Signatures In The Formation Of Low-Mass Protostars. II. Toward Reconciling Models And Observations
A long-standing problem in low-mass star formation is the "luminosity problem," whereby protostars are underluminous compared to the accretion luminosity expected both from theoretical collapse calculations and arguments based on the minimum accretion rate necessary to form a star within the embedded phase duration. Motivated by this luminosity problem, we present a set of evolutionary models describing the collapse of low-mass, dense cores into protostars. We use as our starting point the evolutionary model following the inside-out collapse of a singular isothermal sphere as presented by Young & Evans. We calculate the radiative transfer of the collapsing core throughout the full duration of the collapse in two dimensions. From the resulting spectral energy distributions, we calculate standard observational signatures (L(bol), T(bol), L(bol)/L(smm)) to directly compare to observations. We incorporate several modifications and additions to the original Young & Evans model in an effort to better match observations with model predictions; we include (1) the opacity from scattering in the radiative transfer, (2) a circumstellar disk directly in the two-dimensional radiative transfer, (3) a two-dimensional envelope structure, taking into account the effects of rotation, (4) mass-loss and the opening of outflow cavities, and (5) a simple treatment of episodic mass accretion. We find that scattering, two-dimensional geometry, mass-loss, and outflow cavities all affect the model predictions, as expected, but none resolve the luminosity problem. On the other hand, we find that a cycle of episodic mass accretion similar to that predicted by recent theoretical work can resolve this problem and bring the model predictions into better agreement with observations. Standard assumptions about the interplay between mass accretion and mass loss in our model give star formation efficiencies consistent with recent observations that compare the core mass function and stellar initial mass function. Finally, the combination of outflow cavities and episodic mass accretion reduces the connection between observational class and physical stage to the point where neither of the two commonly used observational signatures (T(bol) and L(bol)/L(smm)) can be considered reliable indicators of physical stage.NASA 1224608, 1288664, 1288658, RSA 1377304, NNX 07-AJ72GNSF AST0607793UT Austin University Continuing FellowshipAstronom
Quasi-Periodic Oscillations from Magnetorotational Turbulence
Quasi-periodic oscillations (QPOs) in the X-ray lightcurves of accreting
neutron star and black hole binaries have been widely interpreted as being due
to standing wave modes in accretion disks. These disks are thought to be highly
turbulent due to the magnetorotational instability (MRI). We study wave
excitation by MRI turbulence in the shearing box geometry. We demonstrate that
axisymmetric sound waves and radial epicyclic motions driven by MRI turbulence
give rise to narrow, distinct peaks in the temporal power spectrum. Inertial
waves, on the other hand, do not give rise to distinct peaks which rise
significantly above the continuum noise spectrum set by MRI turbulence, even
when the fluid motions are projected onto the eigenfunctions of the modes. This
is a serious problem for QPO models based on inertial waves.Comment: 4 pages, 2 figures. submitted to ap
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