1,927 research outputs found
MHD Wave Propagation in the Neighbourhood of Two Null Points
The nature of fast magnetoacoustic and Alfv\'en waves is investigated in a
zero plasma in the neighbourhood of a pair of two-dimensional null
points. This gives an indication of wave propagation in the low solar
corona, for a more complicated magnetic configuration than that looked at by
McLaughlin & Hood (2004). It is found that the fast wave is attracted to the
null points and that the front of the wave slows down as it approaches the null
point pair, with the wave splitting and part of the wave accumulating at one
null and the rest at the other. Current density will then accumulate at these
points and ohmic dissipation will then extract the energy in the wave at these
points. This suggests locations where wave heating will occur in the corona.
The Alfv\'en wave behaves in a different manner in that the wave accumulates
along the separatrices. Hence, the current density will accumulate at this part
of the topology and this is where wave heating will occur. However, the
phenomenon of wave accumulation at a specific place is a feature of both wave
types, and illustrates the importance of studying the topology of the corona
when considering MHD wave propagation.Comment: 11 pages, 14 figure
Space Climate Manifestation in Earth Prices - from Medieval England Up to Modern Usa
In this study we continue to search for possible manifestations of space
weather influence on prices of agricultural products and consumables. We note
that the connection between solar activity and prices is based on the causal
chain that includes several nonlinear transition elements. These non-linear
elements are characterized by threshold sensitivity to external parameters and
lead to very inhomogeneous local sensitivity of the price to space weather
conditions. It is noted that "soft type" models are the most adequate for
description of this class of connections. Two main observational effects
suitable for testing causal connections of this type of sensitivity are
considered: burst-like price reactions on changes in solar activity and price
asymmetry for selected phases of the sunspot cycle. The connection, discovered
earlier for wheat prices of Medieval England, is examined in this work on the
basis of another 700-year data set of consumable prices in England. Using the
same technique as in the previous part of our work (Pistilnik and Yom Din 2004)
we show that statistical parameters of the interval distributions for price
bursts of consumables basket and for sunspot minimum states are similar one to
another, like it was reported earlier for wheat price bursts. Possible sources
of these consistencies between three different multiyear samples are discussed.
For search of possible manifestations of the "space weather - wheat market"
connection in modern time, we analyze dynamics of wheat prices in the USA in
the twentieth century. We show that the wheat prices revealed a maximum/minimum
price asymmetry consistent with the phases of the sunspot cycle. We discuss
possible explanations of this observed asymmetry, unexpected under conditions
of globalization of the modern wheat market.Comment: First International Symposium on Space Climate: Direct and Indirect
Observations of Long-Term Solar Activity, 20-23 June 2004, Oulu, Finlan
Characterization of Automotive Paint Clear Coats by Ultraviolet Absorption Microspectrophotometry with Subsequent Chemometric Analysis
Clear coats have been a staple in automobile paints for almost thirty years and are of forensic interest when comparing transferred and native paints. However, the ultraviolet (UV) absorbers in these paint layers are not typically characterized using UV microspectrophotometry, nor are the results studied using multivariate statistical methods. In this study, measurements were carried out by UV microspectrophotometry on 71 samples from American and Australian automobiles, with subsequent chemometric analysis of the absorbance spectra. Sample preparation proved to be vital in obtaining accurate absorbance spectra and a method involving peeling the clear coat layer and not using a mounting medium was preferred. Agglomerative hierarchical clustering indicated three main groups of spectra, corresponding to spectra with one, two, and three maxima. Principal components analysis confirmed this clustering and the factor loadings indicated that a substantial proportion of the variance in the data set originated from specific spectral regions (230-265 nm, 275-285 nm, and 300-370 nm). The three classes were well differentiated using discriminant analysis, where the cross-validation accuracy was 91.6% and the external validation accuracy was 81.1%. However, results showed no correlation between the make, model, and year of the automobiles
Biodistribution of 64 Cu in Inflamed Rats Following Administration of Two Anti-Inflammatory Copper Complexes
64Cu was administered in two anti-inflammatory formulations to normal rats and to rats with 2 forms of local inflammation, namely (a) an acute paw oedema (elicited with carrageenan) or (b) a chronic granulomatous response to an implanted irritant (Mycobacterium tuberculosis in a polyurethane sponge). The copper formulations used were (i) a slow release one consisting of Cu(II) salicylate applied dermally with ethanol/DMSO and (ii) short acting hydrophilic complex (Cu(I)Cu(II)-penicillamine)5- given subcutaneously. Three types of changes in copper biodistribution with these forms of inflammation were discerned based on determination of 64Cu and copper content in the following organs: inflammatory locus (foot or sponge implant), kidney, liver, spleen, adrenals, brain, blood, thymus, heart, and skin (site of application). The most evident changes were in the kidneys, liver, spleen, adrenals, thymus and serum from animals with chronic granulomatous inflammation. In contrast, a short term acute inflammatory stress (carrageenan paw oedema) had little effect. While copper D-penicillamine (applied subcutaneously) appeared to move as a bolus through the animals, the results with the percutaneous copper salicylate formulation are consistent with it providing a slow release source of copper(II). Exogenous 64Cu from both formulations was sequestered at inflammatory sites (relative to serum). This may partly explain how applied copper complexes can be anti-inflammatory
Resonant Formation of Molecules in Deuterium: An Atomic Beam Measurement of Muon Catalyzed dt Fusion
Resonant formation of molecules in collisions of muonic tritium
() on D was investigated using a beam of atoms,
demonstrating a new direct approach in muon catalyzed fusion studies. Strong
epithermal resonances in formation were directly revealed for the
first time. From the time-of-flight analysis of fusion
events, a formation rate consistent with times the theoretical prediction was obtained. For the largest
peak at a resonance energy of eV, this corresponds to a rate
of s, more than an order of magnitude larger
than those at low energies.Comment: To appear in Phys. Rev. Let
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Wivesâ part-time employment and marital stability in Great Britain, West Germany and the United States
Many hail wivesâ part-time employment as a workâfamily balance strategy, but theories offer competing predictions as to the effects of wivesâ employment on relationship stability. We use panel data to test these competing hypotheses among recent cohorts of first-married couples in Great Britain, West Germany 1 and the United States. We find effects of wivesâ employment on marital stability var y across the countries. In West Germany with its high-quality part-time employment, couples where the wife works part time are significantly more stable. In the more liberal British and US labour markets, neither wivesâ part- nor full-time employment significantly alters divorce risk. In the United States, however, mothers working part time have significantly lower divorce risk. West German and British husbandsâ unemployment proves more detrimental to marital stability than wivesâ employment. These results highlight the importance of the socioeconomic context in structuring the optimal employment participation of both partners
Strigolactones positively regulate chilling tolerance in pea and in Arabidopsis
Strigolactones (SL) fulfil important roles in plant development and stress tolerance. Here, we characterized the role of SL in the dark chilling tolerance of pea and Arabidopsis by analysis of mutants that are defective in either SL synthesis or signalling. Pea mutants (rms3, rms4, and rms5) had significantly greater shoot branching with higher leaf chlorophyll a/b ratios and carotenoid contents than the wild type. Exposure to dark chilling significantly decreased shoot fresh weights but increased leaf numbers in all lines. Moreover, dark chilling treatments decreased biomass (dry weight) accumulation only in rms3 and rms5 shoots. Unlike the wild type plants, chillingâinduced inhibition of photosynthetic carbon assimilation was observed in the rms lines and also in the Arabidopsis max3â9, max4â1, and max2â1 mutants that are defective in SL synthesis or signalling. When grown on agar plates, the max mutant rosettes accumulated less biomass than the wild type. The synthetic SL, GR24, decreased leaf area in the wild type, max3â9, and max4â1 mutants but not in max2â1 in the absence of stress. In addition, a chillingâinduced decrease in leaf area was observed in all the lines in the presence of GR24. We conclude that SL plays an important role in the control of dark chilling tolerance.BBSRC, Grant/Award Number: BB/K501839/1https://wileyonlinelibrary.com/journal/pce2019-06-01hj2018Forestry and Agricultural Biotechnology Institute (FABI)Plant Production and Soil Scienc
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Actinide biocolloid formation in brine by halophilic bacteria
The authors examined the ability of a halophilic bacterium (WIPP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited solubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellularly as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide
Spiral valve parasites of blue and common thresher sharks as indicators of shark feeding behaviour and ecology
Open Access via the Jisc Wiley agreement Acknowledgements This work would not have been possible without the assistance and samples provided by the National Marine Fisheries Service (NMFS) Southwest Region Fishery Observer Program and the participating drift gillnet fishermen. A. Arevalo, E. Reed, H. Colley, J. Williams, J. Tamez and K. Tran assisted with spiral valve dissections and parasite sorting in the lab. D. Losey helped with library research. D. Sweetnam, A. Yau, A. Thompson, M. Craig, S. Stohs, G. DiNardo provided constructive critiques that helped improve the manuscript. This research was supported by the National Oceanographic Atmospheric Administration (NOAA).Peer reviewedPublisher PD
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