Testing the current paradigm for space weather prediction with heliospheric imagers

Predictions of the arrival of four coronal mass ejections (CMEs) in geospace are produced through use of three CME geometric models combined with CME drag modeling, constraining these models with the available Coronagraph and Heliospheric Imager data. The efficacy of these predications is assessed by comparison with the Space Weather Prediction Center (SWPC) numerical MHD forecasts of these same events. It is found that such a prediction technique cannot outperform the standard SWPC forecast at a statistically meaningful level. We test the Harmonic Mean, Self-Similar Expansion, and Ellipse Evolution geometric models, and find that, for these events at least, the differences between the models are smaller than the observational errors. We present a new method of characterizing CME fronts in the Heliospheric Imager field of view, utilizing the analysis of citizen scientists working with the Solar Stormwatch project, and we demonstrate that this provides a more accurate representation of the CME front than is obtained by experts analyzing elongation time maps for the studied events. Comparison of the CME kinematics estimated independently from the STEREO-A and STEREO-B Heliospheric Imager data reveals inconsistencies that cannot be explained within the observational errors and model assumptions. We argue that these observations imply that the assumptions of the CME geometric models are routinely invalidated and question their utility in a space weather forecasting context. These results argue for the continuing development of more advanced techniques to better exploit the Heliospheric Imager observations for space weather forecasting

Using the ionospheric response to the solar eclipse on 20th March 2015 to detect spatial structure in the solar corona

Long-term variability has previously been observed in the relative magnitude of annual and semi-annual variations in the critical frequency (related to the peak electron concentration) of the ionospheric F2 layer (foF2). In this paper we investigate the global patterns in such variability by calculating the time varying power ratio of semi-annual to annual components seen in ionospheric foF2 data sequences from 77 ionospheric monitoring stations around the world. The temporal variation in power ratios observed at each station was then correlated with the same parameter calculated from similar epochs for the Slough/Chilton data set (for which there exists the longest continuous sequence of ionospheric data). This technique reveals strong regional variation in the data, which bears a striking similarity to the regional variation observed in long-term changes to the height of the ionospheric F2 layer. We argue that since both the height and peak density of the ionospheric F2 region are influenced by changes to thermospheric circulation and composition, the observed long-term and regional variability can be explained by such changes. In the absence of long-term measurements of thermospheric composition, detailed modelling work is required to investigate these processes

Open urethroplasty versus endoscopic urethrotomy - clarifying the management of men with recurrent urethral stricture (the OPEN trial) : study protocol for a randomised controlled trial

Peer reviewedPublisher PD

Mechanistic insight into proton-coupled mixed valency

Stabilisation of the mixed-valence state in [Mo2(TiPB)3(HDOP)]2+ (HTiPB = 2,4,6-triisopropylbenzoic acid, H2DOP = 3,6-dihydroxypyridazine) by electron transfer (ET) is related to the proton coordinate of the bridging ligands. Spectroelectrochemical studies suggest that ET is slower than 109 s−1. The mechanism has been probed using DFT calculations, which show that proton transfer induces a larger dipole in the molecule resulting in ET

Enhancing the Air Stability of Dimolybdenum Paddlewheel Complexes : Redox Tuning through Fluorine Substituents

The optical and electrochemical properties of quadruply bonded dimolybdenum paddlewheel complexes (Mo2PWCs) make them ideal candidates for incorporation into functional materials or devices, but one of the greatest bottlenecks for this is their poor stability toward atmospheric oxygen. By tuning the potential at which the Mo2 core is oxidized, it was possible to increase the tolerance of Mo2PWCs to air. A series of homoleptic Mo2PWCs bearing fluorinated formamidinate ligands have been synthesized and their electrochemical properties studied. The oxidation potential of the complexes was tuned in a predictable fashion by controlling the positions of the fluorine substituents on the ligands, as guided by a Hammett relationship. Studies into the air stability of the resulting complexes by multinuclear NMR spectroscopy show an increased tolerance to atmospheric oxygen with increasingly electron-withdrawing ligands. The heteroleptic complex Mo2(DFArF)3(OAc) [where DFArF = 3,5-(difluorophenyl)formamidinate] shows remarkable tolerance to oxygen in the solid state and in chloroform solutions. Through the employment of easily accessible ligands, the stability of the Mo2 core toward oxygen has been enhanced, thereby making Mo2PWCs with electron-withdrawing ligands more attractive candidates for the development of functional materials

The effectiveness of the Inspiring Futures parenting programme in improving behavioural and emotional outcomes in primary school children with behavioural or emotional difficulties: study protocol for a randomised controlled trial.

textabstractBackground: There is a need to build the evidence base of early interventions promoting children's health and development in the UK. Malachi Specialist Family Support Services ('Malachi') is a voluntary sector organisation based in the UK that delivers a therapeutic parenting group programme called Inspiring Futures to parents of children identified as having behavioural and emotional difficulties. The programme comprises two parts, delivered sequentially: (1) a group-based programme for all parents for 10-12 weeks, and (2) one-to-one sessions with selected parents from the group-based element for up to 12 weeks. Methods/design: A randomised controlled trial will be conducted to evaluate Malachi's Inspiring Futures parenting programme. Participants will be allocated to one of two possible arms, with follow-up measures at 16 weeks (post-parent group programme) and at 32 weeks (post-one-to-one sessions with selected parents). The sample size is 248 participants with a randomisation allocation ratio of 1:1. The intervention arm will be offered the Inspiring Futures programme. The control group will receive services as usual. The aim is to determine the effectiveness of the Inspiring Futures programme on the primary outcome of behavioural and emotional difficulties of primary school children identified as having behavioural or emotional difficulties. Discussion: This study will further enhance the evidence for early intervention parenting programmes for child behavioural and emotional problems in the UK

The Discovery Potential of a Super B Factory

The Proceedings of the 2003 SLAC Workshops on flavor physics with a high luminosity asymmetric e+e- collider. The sensitivity of flavor physics to physics beyond the Standard Model is addressed in detail, in the context of the improvement of experimental measurements and theoretical calculations.Comment: 476 pages. Printed copies may be obtained by request to [email protected] . arXiv admin note: v2 appears to be identical to v

Tracking CMEs using data from the Solar Stormwatch project; observing deflections and other properties

With increasing technological dependence, society is becoming ever more affected by changes in the near-Earth space environment caused by space weather. The primary driver of these hazards are coronal mass ejections (CMEs). Solar Stormwatch is a citizen science project in which volunteers participated in several activities which characterised CMEs in the remote sensing images from the SECCHI instrument package on the twin STEREO spacecraft. Here, we analyse the results of the 'Track-it-back' activity, in which CMEs were tracked back through the COR2, COR1 and EUVI images. Analysis of the COR1, COR2 and EUVI data together allows CMEs to be studied consistently throughout the whole field-of-view spanned by these instruments (out to 15 solar radii). 4783 volunteers took part in this activity, creating a dataset containing 23,801 estimates of CME timing, location and size. We used this data to produce a catalogue of 41 CMEs, which is the first to consistently track CMEs through each of these instruments. We assess how the CME speeds, propagation directions and widths vary as the CMEs propagate through the fields of view of the different imagers. In particular, we compare the observed CME deflections between the COR1 and COR2 fields of view to the separation between the CME source region and the heliospheric current sheet (HCS), demonstrating that, in general, these CMEs appear to deflect towards the HCS, consistent with other modelling studies of CME propagation