232 research outputs found
Better by design: Rethinking interventions for better environmental regulation
etter regulation seeks to extend existing policy and regulatory outcomes at less burden for the actors involved. No single intervention will deliver all environmental outcomes. There is a paucity of evidence on what works why, when and with whom. We examine how a sample (n=33) of policy makers select policy and regulatory instruments, through a case study of the Department for Environment, Food and Rural Affairs (Defra), UK. Policy makers have a wide range of instruments at their disposal and are seeking ways to harness the influence of non-governmental resources to encourage good environmental behaviour. The relevance of each influence varies as risk and industry characteristics vary between policy areas. A recent typology of policy and regulatory instruments has been refined. Direct regulation is considered necessary in many areas, to reduce environmental risks with confidence and to tackle poor environmental performance. Co-regulatory approaches may provide important advantages to help accommodate uncertainty for emerging policy problems, providing a mechanism to develop trusted evidence and to refine objectives as problems are better understood
Observed Limits on Charge Exchange Contributions to the Diffuse X-ray Background
We present a high resolution spectrum of the diffuse X-ray background from
0.1 to 1 keV for a ~1 region of the sky centered at l=90, b=+60 using a
36-pixel array of microcalorimeters flown on a sounding rocket. With an energy
resolution of 11 eV FWHM below 1 keV, the spectrum's observed line ratios help
separate charge exchange contributions originating within the heliosphere from
thermal emission of hot gas in the interstellar medium. The X-ray sensitivity
below 1 keV was reduced by about a factor of four from contamination that
occurred early in the flight, limiting the significance of the results. The
observed centroid of helium-like O VII is 568+2-3 eV at 90% confidence. Since
the centroid expected for thermal emission is 568.4 eV while for charge
exchange is 564.2 eV, thermal emission appears to dominate for this line
complex, consistent with much of the high-latitude O VII emission originating
in 2-3 x 10^6 K gas in the Galactic halo. On the other hand, the observed ratio
of C VI Ly gamma to Ly alpha is 0.3+-0.2. The expected ratios are 0.04 for
thermal emission and 0.24 for charge exchange, indicating that charge exchange
must contribute strongly to this line and therefore potentially to the rest of
the ROSAT R12 band usually associated with 10^6 K emission from the Local Hot
Bubble. The limited statistics of this experiment and systematic uncertainties
due to the contamination require only >32% thermal emission for O VII and >20%
from charge exchange for C VI at the 90% confidence level. An experimental gold
coating on the silicon substrate of the array greatly reduced extraneous
signals induced on nearby pixels from cosmic rays passing through the
substrate, reducing the triggered event rate by a factor of 15 from a previous
flight of the instrument.Comment: 14 pages, 7 figures, to be published in Ap
Better by design: Rethinking interventions for better environmental regulation
Better regulation seeks to extend existing policy and regulatory outcomes at less burden for the actors involved. No single intervention will deliver all environmental outcomes. There is a paucity of evidence on what works why, when and with whom. We examine how a sample (n=33) of policy makers select policy and regulatory instruments, through a case study of the Department for Environment, Food and Rural Affairs (Defra), UK. Policy makers have a wide range of instruments at their disposal and are seeking ways to harness the influence of non-governmental resources to encourage good environmental behaviour. The relevance of each influence varies as risk and industry characteristics vary between policy areas. A recent typology of policy and regulatory instruments has been refined. Direct regulation is considered necessary in many areas, to reduce environmental risks with confidence and to tackle poor environmental performance. Co-regulatory approaches may provide important advantages to help accommodate uncertainty for emerging policy problems, providing a mechanism to develop trusted evidence and to refine objectives as problems are better understood
Complex impedance measurements of calorimeters and bolometers: correction for stray impedances
Impedance measurements provide a useful probe of the physics of bolometers
and calorimeters. We describe a method for measuring the complex impedance of
these devices. In previous work, stray impedances and readout electronics of
the measurement apparatus have resulted in artifacts in the impedance data. The
new technique allows experimenters to find an independent Thevenin or Norton
equivalent circuit for each frequency. This method allows experimenters to
easily isolate the device impedance from the effects of parasitic impedances
and frequency dependent gains in amplifiers.Comment: 5 pages, 6 figure
The Milky Way's Kiloparsec Scale Wind: A Hybrid Cosmic-Ray and Thermally Driven Outflow
We apply a wind model, driven by combined cosmic-ray and thermal-gas
pressure, to the Milky Way, and show that the observed Galactic diffuse soft
X-ray emission can be better explained by a wind than by previous static gas
models. We find that cosmic-ray pressure is essential to driving the observed
wind. Having thus defined a "best-fit" model for a Galactic wind, we explore
variations in the base parameters and show how the wind's properties vary with
changes in gas pressure, cosmic-ray pressure and density. We demonstrate the
importance of cosmic rays in launching winds, and the effect cosmic rays have
on wind dynamics. In addition, this model adds support to the hypothesis of
Breitschwerdt and collaborators that such a wind may help explain the
relatively small gradient observed in gamma-ray emission as a function of
galactocentric radius.Comment: 14 pages, 11 figures; Accepted to Ap
A characteristic lengthscale causes anomalous size effects and boundary programmability in mechanical metamaterials
The architecture of mechanical metamaterialsis designed to harness geometry,
non-linearity and topology to obtain advanced functionalities such as shape
morphing, programmability and one-way propagation. While a purely geometric
framework successfully captures the physics of small systems under idealized
conditions, large systems or heterogeneous driving conditions remain
essentially unexplored. Here we uncover strong anomalies in the mechanics of a
broad class of metamaterials, such as auxetics, shape-changers or topological
insulators: a non-monotonic variation of their stiffness with system size, and
the ability of textured boundaries to completely alter their properties. These
striking features stem from the competition between rotation-based
deformations---relevant for small systems---and ordinary elasticity, and are
controlled by a characteristic length scale which is entirely tunable by the
architectural details. Our study provides new vistas for designing, controlling
and programming the mechanics of metamaterials in the thermodynamic limit.Comment: Main text has 4 pages, 4 figures + Methods and Supplementary
Informatio
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future
ADAMTS1 alters blood vessel morphology and TSP1 levels in LNCaP and LNCaP-19 prostate tumors
<p>Abstract</p> <p>Background</p> <p>Decreased expression of the angiogenesis inhibitor ADAMTS1 (ADAM metallopeptidase with thrombospondin type 1 motif, 1) has previously been reported during prostate cancer progression. The aim of this study was to investigate the function of ADAMTS1 in prostate tumors.</p> <p>Methods</p> <p>ADAMTS1 was downregulated by shRNA technology in the human prostate cancer cell line LNCaP (androgen-dependent), originally expressing ADAMTS1, and was upregulated by transfection in its subline LNCaP-19 (androgen-independent), expressing low levels of ADAMTS1. Cells were implanted subcutaneously in nude mice and tumor growth, microvessel density (MVD), blood vessel morphology, pericyte coverage and thrombospondin 1 (TSP1) were studied in the tumor xenografts.</p> <p>Results</p> <p>Modified expression of ADAMTS1 resulted in altered blood vessel morphology in the tumors. Low expression levels of ADAMTS1 were associated with small diameter blood vessels both in LNCaP and LNCaP-19 tumors, while high levels of ADAMTS1 were associated with larger vessels. In addition, TSP1 levels in the tumor xenografts were inversely related to ADAMTS1 expression. MVD and pericyte coverage were not affected. Moreover, upregulation of ADAMTS1 inhibited tumor growth of LNCaP-19, as evidenced by delayed tumor establishment. In contrast, downregulation of ADAMTS1 in LNCaP resulted in reduced tumor growth rate.</p> <p>Conclusions</p> <p>The present study demonstrates that ADAMTS1 is an important regulatory factor of angiogenesis and tumor growth in prostate tumors, where modified ADAMTS1 expression resulted in markedly changed blood vessel morphology, possibly related to altered TSP1 levels.</p
An AKAP-Lbc-RhoA interaction inhibitor promotes the translocation of aquaporin-2 to the plasma membrane of renal collecting duct principal cells
Stimulation of renal collecting duct principal cells with antidiuretic hormone (arginine-vasopressin, AVP) results in inhibition of the small GTPase RhoA and the enrichment of the water channel aquaporin-2 (AQP2) in the plasma membrane. The membrane insertion facilitates water reabsorption from primary urine and fine-tuning of body water homeostasis. Rho guanine nucleotide exchange factors (GEFs) interact with RhoA, catalyze the exchange of GDP for GTP and thereby activate the GTPase. However, GEFs involved in the control of AQP2 in renal principal cells are unknown. The A-kinase anchoring protein, AKAP-Lbc, possesses GEF activity, specifically activates RhoA, and is expressed in primary renal inner medullary collecting duct principal (IMCD) cells. Through screening of 18,431 small molecules and synthesis of a focused library around one of the hits, we identified an inhibitor of the interaction of AKAP-Lbc and RhoA. This molecule, Scaff10-8, bound to RhoA, inhibited the AKAP-Lbc-mediated RhoA activation but did not interfere with RhoA activation through other GEFs or activities of other members of the Rho family of small GTPases, Rac1 and Cdc42. Scaff10-8 promoted the redistribution of AQP2 from intracellular vesicles to the periphery of IMCD cells. Thus, our data demonstrate an involvement of AKAP-Lbc-mediated RhoA activation in the control of AQP2 trafficking
Energy band diagram of device-grade silicon nanocrystals
This work was supported by the EPSRC (EP/K022237/1) and the Leverhulme International Network (IN-2012-136). SA would like to acknowledge the support of the Ulster University Vice-Chancellor's Research Studentship and CR that of the NI-DEL studentship.Device grade silicon nanocrystals (NCs) are synthesized using an atmospheric-pressure plasma technique. The Si NCs have a small and well defined size of about 2.3 nm. The synthesis system allows for the direct creation of thin films, enabling a range of measurements to be performed and easy implementation of this material in different devices. The chemical stability of the Si NCs is evaluated, showing relatively long-term durability thanks to hydrogen surface terminations. Optical and electrical characterization techniques, including Kelvin probe, ultraviolet photoemission spectroscopy and Mott-Schottky analysis, are employed to determine the energy band diagram of the Si NCs.Publisher PDFPeer reviewe
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