2,747 research outputs found
Discretion in Administrative Law
If administrative law is seen as the study of the use of power, one of its most important interests is discretion, since the limits on discretion are at the same time the limits on the power that anyone can have in our type of democracy. The massive expansion of the powers of the state, and the growth of immensely powerful committees, commissions and other bodies, against which may be juxtaposed a new and fervent interest in civil liberties and human rights, renders a re-examination of discretion and discretionary powers both essential and inevitable. It is the purpose of this essay to clarify the concept of discretion, to demonstrate how far the courts have been willing to tolerate it, and to chart some of the new paths that appear to be opening before those who advocate wide judicial review
Hydrodynamic induced deformation and orientation of a microscopic elastic filament
We describe simulations of a microscopic elastic filament immersed in a fluid
and subject to a uniform external force. Our method accounts for the
hydrodynamic coupling between the flow generated by the filament and the
friction force it experiences. While models that neglect this coupling predict
a drift in a straight configuration, our findings are very different. Notably,
a force with a component perpendicular to the filament axis induces bending and
perpendicular alignment. Moreover, with increasing force we observe four shape
regimes, ranging from slight distortion to a state of tumbling motion that
lacks a steady state. We also identify the appearance of marginally stable
structures. Both the instability of these shapes and the observed alignment can
be explained by the combined action of induced bending and non-local
hydrodynamic interactions. Most of these effects should be experimentally
relevant for stiff micro-filaments, such as microtubules.Comment: three figures. To appear in Phys Rev Let
Molecular Basis of Prostate Cancer Diagnostics and Therapeutics
Prostate Cancer is now the second biggest cause of cancer mortality in the UK. Media coverage has been rising, with some attributing to a rise in the cases diagnosed and treated in the NHS down to the “Fry and Turnbull effect”. Our understanding of prostate cancer has increased tremendously in the past decades, with advances in molecular biology and genomics driving the way to new treatments and diagnostics. This Special Edition of Translational Andrology and Urology 2019: Prostate Cancer Biology and Genomics aims to review the current state of prostate cancer genomics, proteomics, diagnostics and treatment
Survival of near-critical branching Brownian motion
Consider a system of particles performing branching Brownian motion with
negative drift and killed upon hitting zero.
Initially there is one particle at . Kesten showed that the process
survives with positive probability if and only if . Here we are
interested in the asymptotics as \eps\to 0 of the survival probability
. It is proved that if then for all , exists and is a
travelling wave solution of the Fisher-KPP equation. Furthermore, we obtain
sharp asymptotics of the survival probability when and .
The proofs rely on probabilistic methods developed by the authors in a previous
work. This completes earlier work by Harris, Harris and Kyprianou and confirms
predictions made by Derrida and Simon, which were obtained using nonrigorous
PDE methods
Observations of mesoscale and boundary-layer circulations affecting dust uplift and transport in the Saharan boundary layer
International audienceObservations of the Saharan boundary layer, made during the GERBILS field campaign, show that mesoscale land surface temperature variations (which were related to albedo variations) induced mesoscale circulations, and that mesoscale and boundary-layer circulations affected dust uplift and transport. These processes are unrepresented in many climate models, but may have significant impacts on the vertical transport and uplift of desert dust. Mesoscale effects in particular tend to be difficult to parameterise. With weak winds along the aircraft track, land surface temperature anomalies with scales of greater than 10 km are shown to significantly affect boundary-layer temperatures and winds. Such anomalies are expected to affect the vertical mixing of the dusty and weakly stratified Saharan Air Layer (SAL). Mesoscale variations in winds are also shown to affect dust loadings in the boundary-layer. In a region of local uplift, with strong along-track winds, boundary-layer rolls are shown to lead to warm moist dusty updraughts in the boundary layer. Large eddy model (LEM) simulations suggest that these rolls increased uplift by approximately 30%. The modelled effects of boundary-layer convection on uplift is shown to be larger when the boundary-layer wind is decreased, and most significant when the mean wind is below the threshold for dust uplift and the boundary-layer convection leads to uplift which would not otherwise occur
Observations of mesoscale and boundary-layer scale circulations affecting dust transport and uplift over the Sahara
Observations of the Saharan boundary layer, made during the GERBILS field campaign, show that mesoscale land surface temperature variations (which were related to albedo variations) induced mesoscale circulations. With weak winds along the aircraft track, land surface temperature anomalies with scales of greater than 10 km are shown to significantly affect boundary-layer temperatures and winds. Such anomalies are expected to affect the vertical mixing of the dusty and weakly stratified Saharan Residual Layer (SRL). Mesoscale variations in winds are also shown to affect dust loadings in the boundary layer. <br><br> Using the aircraft observations and data from the COSMO model, a region of local dust uplift, with strong along-track winds, was identified in one low-level flight. Large eddy model (LEM) simulations based on this location showed linearly organised boundary-layer convection. Calculating dust uplift rates from the LEM wind field showed that the boundary-layer convection increased uplift by approximately 30%, compared with the uplift rate calculated neglecting the convection. The modelled effects of boundary-layer convection on uplift are shown to be larger when the boundary-layer wind is decreased, and most significant when the mean wind is below the threshold for dust uplift and the boundary-layer convection leads to uplift which would not otherwise occur. <br><br> Both the coupling of albedo features to the atmosphere on the mesoscale, and the enhancement of dust uplift by boundary-layer convection are unrepresented in many climate models, but may have significant impacts on the vertical transport and uplift of desert dust. Mesoscale effects in particular tend to be difficult to parametrise
Proteasome-associated HECT-type ubiquitin ligase activity is required for plant immunity
<div><p>Regulated degradation of proteins by the 26S proteasome plays important roles in maintenance and signalling in eukaryotic cells. Proteins are marked for degradation by the action of E3 ligases that site-specifically modify their substrates by adding chains of ubiquitin. Innate immune signalling in plants is deeply reliant on the ubiquitin-26S proteasome system. While progress has been made in understanding substrate ubiquitination during plant immunity, how these substrates are processed upon arrival at the proteasome remains unclear. Here we show that specific members of the HECT domain-containing family of ubiquitin protein ligases (UPL) play important roles in proteasomal substrate processing during plant immunity. Mutations in <i>UPL1</i>, <i>UPL3</i> and <i>UPL5</i> significantly diminished immune responses activated by the immune hormone salicylic acid (SA). In depth analyses of <i>upl3</i> mutants indicated that these plants were impaired in reprogramming of nearly the entire SA-induced transcriptome and failed to establish immunity against a hemi-biotrophic pathogen. UPL3 was found to physically interact with the regulatory particle of the proteasome and with other ubiquitin-26S proteasome pathway components. In agreement, we demonstrate that UPL3 enabled proteasomes to form polyubiquitin chains, thereby regulating total cellular polyubiquitination levels. Taken together, our findings suggest that proteasome-associated ubiquitin ligase activity of UPL3 promotes proteasomal processivity and is indispensable for development of plant immunity.</p></div
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