Evidence of Explosive Evaporation in a Microflare Observed by Hinode/EIS

We present a detailed study of explosive chromospheric evaporation during a microflare which occurred on 2007 December 7 as observed with the EUV Imaging Spectrometer (EIS) onboard Hinode. We find temperature-dependent upflows for lines formed from 1.0 to 2.5 MK and downflows for lines formed from 0.05 to 0.63 MK in the impulsive phase of the flare. Both the line intensity and the nonthermal line width appear enhanced in most of the lines and are temporally correlated with the time when significant evaporation was observed. Our results are consistent with the numerical simulations of flare models, which take into account a strong nonthermal electron beam in producing the explosive chromospheric evaporation. The explosive evaporation observed in this microflare implies that the same dynamic processes may exist in events with very different magnitudes.Comment: 14 pages, 8 figures. Accepted for publication in the Astrophysical Journa

Pharmacokinetic Studies with Piroxicam

When one examines the scientific literature pertaining to the NANSAID, piroxicam, it is clear that controversy of one type or another has not been far away. Perhaps the most serious threat to the drugs existence concerned its reputed potential to induce a range of gastrointestinal toxicity, including perforation and haemorrhage. After intense investigation by the regulatory authorities, however, it was concluded that the data cited were flawed due to reliance on spontaneous Adverse Drug Reaction reports. This controversy, together with the withdrawals of Opren and Osmosin during the 1980's, focused attention on prophylactic remedies for the potentially serious gastrointestinal toxicity exhibited, not only with piroxicam, but with all the NANSAIDs. Initial therapy was confined to the coadministration of H2 receptor antagonists but now other treatments are available. Little interest, however, has been placed on the theoretical interaction between NANSAIDs and cimetidine, an H2 receptor antagonist known to reduce the clearance of drugs that are metabolised via cytochrome P450 hepatic enzymes. Of the two studies that have examined this phenomenon, both have been of such a poor design that definite conclusions have been impossible. Before addressing the question of an interaction, therefore, simulation work was performed to design a study which would ensure the right degree of statistical confidence. The technique known as the Jackknife was introduced, its theory explained and its application to study design optimisation described. A prospective power calculation was performed to determine the number of subjects required to detect a 20% difference in the steady state AUC of piroxicam. The 20% value was chosen because it was considered that any alteration in the AUC, as a result of H2 receptor antagonist coadministration, greater than this value would be clinically significant The interaction study was a randomised crossover design comparing the coadministration of cimetidine and nizatidine in patients receiving chronic piroxicam therapy. No clinically significant interaction was found. There was no statistically significant alteration in the plasma AUCs of piroxicam and its metabolite 5-hydroxypiroxicam. However, the ratio of the two (5-hydroxypiroxicam:piroxicam) showed a statistically significant decrease in combination with either cimetidine or nizatidine. This indicated that a mild inhibition of piroxicam metabolism occurred. It is known that cimetidine binds to all isoenzymes of cytochrome P450 with low affinity, but to only a few with high affinity, resulting in a significant clearance alteration. Nizatidine has been shown to cause mild in vitro inhibition of cytochrome P450. The conclusion must therefore be that the H2 receptor antagonists bind to the isoenzyme responsible for piroxicam metabolism with low affinity, and as a consequence no clinically significant interaction will occur as a result of this combination. Another controversy, but by no means as crucial to the drugs continued availability for prescribing, was the question of whether piroxicam entered the bile and underwent enterohepatic circulation. Only one previous study has attempted to examine this, but it was flawed in its design, which made investigation of this phenomenon compelling. Piroxicam's biliary excretion was examined in one patient with a naso-biliary drain which allowed complete collection of the biliary output. The patient received 80mg of piroxicam over 3 days and samples of bile, urine and plasma were collected over a 24 hour period and quantitated for piroxicam, 5-hydroxypiroxicam, and 5-hydroxypiroxicam glucuronide (after development of a suitable assay technique). Neither piroxicam nor 5-hydroxypiroxicam entered the bile in sufficient quantities to undergo significant enterohepatic circulation. However, 5-hydroxypiroxicam glucuronide was present in the bile in large amounts, but this is likely to become important only if reverse metabolism to reform parent drug takes place. It can be concluded that the "multiple peak" phenomenon in piroxicam plasma concentration/time curves was not a result of enterohepatic circulation. (Abstract shortened by ProQuest.)

Decay Phase Cooling and Inferred Heating of M- and X-class Solar Flares

In this paper, the cooling of 72 M- and X-class flares is examined using GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the observed total cooling times are compared to the predictions of an analytical 0-D hydrodynamic model. It is found that the model does not fit the observations well, but does provide a well defined lower limit on a flare's total cooling time. The discrepancy between observations and the model is then assumed to be primarily due to heating during the decay phase. The decay phase heating necessary to account for the discrepancy is quantified and found be ~50% of the total thermally radiated energy as calculated with GOES. This decay phase heating is found to scale with the observed peak thermal energy. It is predicted that approximating the total thermal energy from the peak is minimally affected by the decay phase heating in small flares. However, in the most energetic flares the decay phase heating inferred from the model can be several times greater than the peak thermal energy.Comment: Published in the Astrophysical Journal, 201

Performance of Major Flare Watches from the Max Millennium Program (2001-2010)

The physical processes that trigger solar flares are not well understood and significant debate remains around processes governing particle acceleration, energy partition, and particle and energy transport. Observations at high resolution in energy, time, and space are required in multiple energy ranges over the whole course of many flares in order to build an understanding of these processes. Obtaining high-quality, co-temporal data from ground- and space- based instruments is crucial to achieving this goal and was the primary motivation for starting the Max Millennium program and Major Flare Watch (MFW) alerts, aimed at coordinating observations of all flares >X1 GOES X-ray classification (including those partially occulted by the limb). We present a review of the performance of MFWs from 1 February 2001 to 31 May 2010, inclusive, that finds: (1) 220 MFWs were issued in 3,407 days considered (6.5% duty cycle), with these occurring in 32 uninterrupted periods that typically last 2-8 days; (2) 56% of flares >X1 were caught, occurring in 19% of MFW days; (3) MFW periods ended at suitable times, but substantial gain could have been achieved in percentage of flares caught if periods had started 24 h earlier; (4) MFWs successfully forecast X-class flares with a true skill statistic (TSS) verification metric score of 0.500, that is comparable to a categorical flare/no-flare interpretation of the NOAA Space Weather Prediction Centre probabilistic forecasts (TSS = 0.488).Comment: 19 pages, 2 figures, accepted for publication in Solar Physic

Next moves? Expanding affordable rental housing in Australia through institutional investment

Efforts to engage institutional investment in rental housing provision were badly damaged by the 2014 termination of the National Rental Affordability Scheme (NRAS); yet lessons can be learned from the NRAS initiative and these should inform a successor program.   Building on our major 2013 study, a newly-published City Futures report reviews the NRAS experience and other emerging developments around the institutional financing of rental housing.    With contributions from (CFRC Visiting Fellow) Judy Yates and Prof Peter Williams (Cambridge University), the report focuses mainly on the Australian context. However, it also references rapidly unfolding UK developments involving both government- and industry-led initiatives that have made major advances in this space over the past two years and which have possible implications for Australia.    Drawing on interviews with finance experts and senior policymakers, as well as a review of recent Australian and UK publications, the report details 10 recommendations to government for action to re-start progress towards this widely-shared policy objective

TaMSH7: A cereal mismatch repair gene that affects fertility in transgenic barley (Hordeum vulgare L.)

Background: Chromosome pairing, recombination and DNA repair are essential processes during meiosis in sexually reproducing organisms. Investigating the bread wheat (Triticum aestivum L.) Ph2 (Pairing homoeologous) locus has identified numerous candidate genes that may have a role in controlling such processes, including TaMSH7, a plant specific member of the DNA mismatch repair family. Results: Sequencing of the three MSH7 genes, located on the short arms of wheat chromosomes 3A, 3B and 3D, has revealed no significant sequence divergence at the amino acid level suggesting conservation of function across the homoeogroups. Functional analysis of MSH7 through the use of RNAi loss-of-function transgenics was undertaken in diploid barley (Hordeum vulgare L.). Quantitative real-time PCR revealed several T0 lines with reduced MSH7 expression. Positive segregants from two T1 lines studied in detail showed reduced MSH7 expression when compared to transformed controls and null segregants. Expression of MSH6, another member of the mismatch repair family which is most closely related to the MSH7 gene, was not significantly reduced in these lines. In both T1 lines, reduced seed set in positive segregants was observed. Conclusion: Results presented here indicate, for the first time, a distinct functional role for MSH7 in vivo and show that expression of this gene is necessary for wild-type levels of fertility. These observations suggest that MSH7 has an important function during meiosis and as such remains a candidate for Ph2.Andrew H Lloyd, Andrew S Milligan, Peter Langridge, and Jason A Abl

Observational Evidence for Gentle Chromospheric Evaporation During the Impulsive Phase of a Solar Flare

Observational evidence for gentle chromospheric evaporation during the impulsive phase of a C9.1 solar flare is presented using data from the Reuven Ramaty High-Energy Solar Spectroscopic Imager and the Coronal Diagnostic Spectrometer on board the Solar and Heliospheric Observatory. Until now, evidence for gentle evaporation has often been reported during the decay phase of solar flares, where thermal conduction is thought to be the driving mechanism. Here we show that the chromospheric response to a low flux of nonthermal electrons (>=5x10^9 ergs cm^-2 s^-1) results in plasma upflows of 13+/-16, 16+/-18, and 110+/-58 km s^-1 in the cool He I and O V emission lines and the 8 MK Fe XIX line. These findings, in conjunction with other recently reported work, now confirm that the dynamic response of the solar atmosphere is sensitively dependent on the flux of incident electrons.Comment: 5 page

A Si IV/O IV electron density diagnostic for the analysis of IRIS solar spectra

Solar spectra of ultraviolet bursts and flare ribbons from the Interface Region Imaging Spectrograph (IRIS) have suggested high electron densities of $>10^{12}$ cm$^{-3}$ at transition region temperatures of 0.1 MK, based on large intensity ratios of Si IV $\lambda$1402.77 to O IV $\lambda$1401.16. In this work a rare observation of the weak O IV $\lambda$1343.51 line is reported from an X-class flare that peaked at 21:41 UT on 2014 October 24. This line is used to develop a theoretical prediction of the Si IV $\lambda$1402.77 to O IV $\lambda$1401.16 ratio as a function of density that is recommended to be used in the high density regime. The method makes use of new pressure-dependent ionization fractions that take account of the suppression of dielectronic recombination at high densities. It is applied to two sequences of flare kernel observations from the October 24 flare. The first shows densities that vary between $3\times 10^{12}$ to $3 \times 10^{13}$ cm$^{-3}$ over a seven minute period, while the second location shows stable density values of around $2\times 10^{12}$ cm$^{-3}$ over a three minute period.Comment: 12 pages, 5 figures, submitted to Ap