104 research outputs found
Simulation of an Industrial Magnetron Using Cathode Modulation
Magnetrons can be phase-locked using external systems. An experimental setup using Gated Field Emission Arrays for the modulated electron injection offers a potential solution to this problem by permitting the injection of electrons into the interaction space. Current work focusses on extending previous simulation results into 3-D. A commercially available industrial cooker magnetron (the L3 CWM-75kW) has been successfully simulated by using the 3-D PIC code VSim under the magnetron’s typical operating conditions (18kV, 5A, 1900G, 896-929GHz). The simulation generated results that are consistent with known experimental results in terms of power and frequency
Ariel - Volume 5 Number 3
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Quantifying Effusion Rates at Active Volcanoes through Integrated Time-Lapse Laser Scanning and Photography
During volcanic eruptions, measurements of the rate at which magma is erupted underpin hazard assessments. For eruptions dominated by the effusion of lava, estimates are often made using satellite data; here, in a case study at Mount Etna (Sicily), we make the first measurements based on terrestrial laser scanning (TLS), and we also include explosive products. During the study period (17–21 July, 2012), regular strombolian explosions were occurring within the Bocca Nuova crater, producing a ~50 m high scoria cone and a small lava flow field. TLS surveys over multi-day intervals determined a mean cone growth rate (effusive and explosive products) of ~0.24 m3s-1. Differences between 0.3-m-resolution DEMs acquired at 10-minute intervals captured the evolution of a breakout lava flow lobe advancing at 0.01–0.03 m3s-1. Partial occlusion within the crater prevented similar measurement of the main flow, but integrating TLS data with time-lapse imagery enabled lava viscosity (7.4 × 105 Pa s) to be derived from surface velocities and, hence, a flux of 0.11 m3s-1 to be calculated. The total dense-rock equivalent magma discharge estimates range from ~0.1 to ~0.2 m3s-1 over the measurement period, and suggest that simultaneous estimates from satellite data are somewhat overestimated. Our results support the use of integrated TLS and time-lapse photography for ground-truthing space-based measurements and highlight the value of interactive image analysis when automated approaches such as particle image velocimetry (PIV) fail
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Nilvadipine suppresses inflammation via inhibition of P-SYK and restores spatial memory deficits in a mouse model of repetitive mild TBI
Abstract: Repeated exposure to mild TBI (mTBI) has been linked to an increased risk of Alzheimer’s disease (AD), chronic traumatic encephalopathy (CTE) and other neurodegenerative diseases. Some pathological features typically observed in AD have been found in postmortem brains of TBI and CTE, hence treatments tested for AD have a potential to be effective against r-mTBI outcomes. Neuroinflammation may present a possible answer due to its central role both in acute brain injury and in chronic degenerative-like disorders. Our previous studies have shown that drug nilvadipine, acting as an inhibitor of spleen tyrosine kinase (SYK), is effective at reducing inflammation, tau hyperphosphorylation and amyloid production in AD mouse models. To demonstrate the effect of nilvadipine in the absence of age-related variables, we introduced the same treatment to young r-mTBI mice. We further investigate therapeutic mechanisms of nilvadipine using its racemic properties. Both enantiomers, (+)-nilvadipine and (−)-nilvadipine, can lower SYK activity, whereas (+)-nilvadipine is also a potent L-type calcium channel blocker (CCB) and shown to be anti-hypertensive. All r-mTBI mice exhibited increased neuroinflammation and impaired cognitive performance and motor functions. Treatment with racemic nilvadipine mitigated the TBI-induced inflammatory response and significantly improved spatial memory, whereas (−)-enantiomer decreased microgliosis and improved spatial memory but failed to reduce the astroglial response to as much as the racemate. These results suggest the therapeutic potential of SYK inhibition that is enhanced when combined with the CCB effect, which indicate a therapeutic advantage of multi-action drugs for r-mTBI
The landscape ecological impact of afforestation on the British uplands and some initiatives to restore native woodland cover
The majority of forest cover in the British Uplands had been lost by the beginning of the
Nineteenth Century, because of felling followed by overgrazing by sheep and deer. The
situation remained unchanged until a government policy of afforestation, mainly by exotic
conifers, after the First World War up to the present day. This paper analyses the distribution
of these predominantly coniferous plantations, and shows how they occupy specific parts of
upland landscapes in different zones throughout Britain. Whilst some landscapes are
dominated by these new forests, elsewhere the blocks of trees are more localised. Although
these forests virtually eliminate native ground vegetation, except in rides and unplanted land,
the major negative impacts are at the landscape level. For example, drainage systems are
altered and ancient cultural landscape patterns are destroyed. These impacts are summarised
and possible ways of amelioration are discussed. By contrast, in recent years, a series of
projects have been set up to restore native forest cover, as opposed to the extensive
plantations of exotic species. Accordingly, the paper then provides three examples of such
initiatives designed to restore native forests to otherwise bare landscapes, as well as setting
them into a policy context. Whilst such projects cover a limited proportion of the British
Uplands they nevertheless restore forest to landscapes at a local level
Prospectus, April 10, 1985
https://spark.parkland.edu/prospectus_1985/1009/thumbnail.jp
Why does bee health matter? The science surrounding honey bee health concerns and what we can do about it
CAST Commentary; QTA2017-1 June 201
Why are households that report the lowest incomes so well-off
Using data from the Living Costs and Food Survey in the UK over 1978-2009 we document that households with extremely low measured income (below 10% of median income) on average spend much more than those with merely moderately low income (those below 50% of median income): in short, the graph of median expenditure against income contains a sharp non-monotonicity (or `tick'). We show that this tick appears, to a greater or lesser extent, over the whole period and across different employment states, levels of education and marital statuses. Of the likely explanations, we provide several arguments that discount over-reporting of expenditure and argue that under-reporting of income plays the major role. In particular, by using a dynamic model of consumption and saving, and paying special attention to poverty dynamics, we show that consumption smoothing cannot explain all the apparent dissaving. Finally, and whatever the reason for the tick, we document that low consumption is better correlated with other measures of living standards than having low income
Meta-analysis of genome-wide association studies for cattle stature identifies common genes that regulate body size in mammals
peer-reviewedH.D.D., A.J.C., P.J.B. and B.J.H. would like to acknowledge the Dairy Futures
Cooperative Research Centre for funding. H.P. and R.F. acknowledge funding
from the German Federal Ministry of Education and Research (BMBF) within the
AgroClustEr ‘Synbreed—Synergistic Plant and Animal Breeding’ (grant 0315527B).
H.P., R.F., R.E. and K.-U.G. acknowledge the Arbeitsgemeinschaft Süddeutscher
Rinderzüchter, the Arbeitsgemeinschaft Österreichischer Fleckviehzüchter
and ZuchtData EDV Dienstleistungen for providing genotype data. A. Bagnato
acknowledges the European Union (EU) Collaborative Project LowInputBreeds
(grant agreement 222623) for providing Brown Swiss genotypes. Braunvieh Schweiz
is acknowledged for providing Brown Swiss phenotypes. H.P. and R.F. acknowledge
the German Holstein Association (DHV) and the Confederación de Asociaciones
de Frisona Española (CONCAFE) for sharing genotype data. H.P. was financially
supported by a postdoctoral fellowship from the Deutsche Forschungsgemeinschaft
(DFG) (grant PA 2789/1-1). D.B. and D.C.P. acknowledge funding from the
Research Stimulus Fund (11/S/112) and Science Foundation Ireland (14/IA/2576).
M.S. and F.S.S. acknowledge the Canadian Dairy Network (CDN) for providing the
Holstein genotypes. P.S. acknowledges funding from the Genome Canada project
entitled ‘Whole Genome Selection through Genome Wide Imputation in Beef Cattle’ and acknowledges WestGrid and Compute/Calcul Canada for providing
computing resources. J.F.T. was supported by the National Institute of Food and
Agriculture, US Department of Agriculture, under awards 2013-68004-20364 and
2015-67015-23183. A. Bagnato, F.P., M.D. and J.W. acknowledge EU Collaborative
Project Quantomics (grant 516 agreement 222664) for providing Brown Swiss
and Finnish Ayrshire sequences and genotypes. A.C.B. and R.F.V. acknowledge
funding from the public–private partnership ‘Breed4Food’ (code BO-22.04-011-
001-ASG-LR) and EU FP7 IRSES SEQSEL (grant 317697). A.C.B. and R.F.V.
acknowledge CRV (Arnhem, the Netherlands) for providing data on Dutch and
New Zealand Holstein and Jersey bulls.Stature is affected by many polymorphisms of small effect in humans1. In contrast, variation in dogs, even within breeds, has been suggested to be largely due to variants in a small number of genes2,3. Here we use data from cattle to compare the genetic architecture of stature to those in humans and dogs. We conducted a meta-analysis for stature using 58,265 cattle from 17 populations with 25.4 million imputed whole-genome sequence variants. Results showed that the genetic architecture of stature in cattle is similar to that in humans, as the lead variants in 163 significantly associated genomic regions (P < 5 × 10−8) explained at most 13.8% of the phenotypic variance. Most of these variants were noncoding, including variants that were also expression quantitative trait loci (eQTLs) and in ChIP–seq peaks. There was significant overlap in loci for stature with humans and dogs, suggesting that a set of common genes regulates body size in mammals
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