UV Spectroscopy of AB Doradus with the Hubble Space Telescope. Impulsive flares and bimodal profiles of the CIV 1549 line in a young star

We observed AB Doradus, a young and active late type star (K0 - K2 IV-V, P= 0.514 d) with the Goddard High Resolution Spectrograph of the post-COSTAR Hubble Space Telescope with the time and spectral resolutions of 27 s and 15 km, respectively. The wavelength band (1531 - 1565 A) included the strong CIV doublet (1548.202 and 1550.774, formed in the transition region at 100 000 K). The mean quiescent CIV flux state was close to the saturated value and 100 times the solar one. The line profile (after removing the rotational and instrumental profiles) is bimodal consisting of two Gaussians, narrow (FWHM = 70 km/s) and broad (FWHM =330km/s). This bimodality is probably due to two separate broadening mechanisms and velocity fields at the coronal base. It is possible that TR transient events (random multiple velocities), with a large surface coverage, give rise to the broadening of the narrow component,while true microflaring is responsible for the broad one. The transition region was observed to flare frequently on different time scales and magnitudes. The largest impulsive flare seen in the CIV 1549 emission reached in less than one minute the peak differential emission measure (10**51.2 cm-3) and returned exponentially in 5 minutes to the 7 times lower quiescent level.The 3 min average line profile of the flare was blue-shifted (-190 km/s) and broadened (FWHM = 800 km/s). This impulsive flare could have been due to a chromospheric heating and subsequent evaporation by an electron beam, accelerated (by reconnection) at the apex of a coronal loop.Comment: to be published in AJ (April 98), 3 tables and 7 figures as separate PS-files, print Table 2 as a landscap

Estimating the masses of extra-solar planets

All extra-solar planet masses that have been derived spectroscopically are lower limits since the inclination of the orbit to our line-of-sight is unknown except for transiting systems. It is, however, possible to determine the inclination angle, i, between the rotation axis of a star and an observer's line-of-sight from measurements of the projected equatorial velocity (v sin i), the stellar rotation period (P_rot) and the stellar radius (R_star). This allows the removal of the sin i dependency of spectroscopically derived extra-solar planet masses under the assumption that the planetary orbits lie perpendicular to the stellar rotation axis. We have carried out an extensive literature search and present a catalogue of v sin i, P_rot, and R_star estimates for exoplanet host stars. In addition, we have used Hipparcos parallaxes and the Barnes-Evans relationship to further supplement the R_star estimates obtained from the literature. Using this catalogue, we have obtained sin i estimates using a Markov-chain Monte Carlo analysis. This allows proper 1-sigma two-tailed confidence limits to be placed on the derived sin i's along with the transit probability for each planet to be determined. While a small proportion of systems yield sin i's significantly greater than 1, most likely due to poor P_rot estimations, the large majority are acceptable. We are further encouraged by the cases where we have data on transiting systems, as the technique indicates inclinations of ~90 degrees and high transit probabilities. In total, we estimate the true masses of 133 extra-solar planets. Of these, only 6 have revised masses that place them above the 13 Jupiter mass deuterium burning limit. Our work reveals a population of high-mass planets with low eccentricities and we speculate that these may represent the signature of different planetary formation mechanisms at work.Comment: 40 pages, 6 tables, 2 figures. Accepted for publication in the Monthly Notices of the Royal Astronomical Society after editing of Tables 1 & 6 for electronic publication. Html abstract shortened for astro-ph submissio

Bistable molecular conductors with a field-switchable dipole group

A class of bistable "stator-rotor" molecules is proposed, where a stationary bridge (stator) connects the two electrodes and facilitates electron transport between them. The rotor part, which has a large dipole moment, is attached to an atom of the stator via a single sigma bond. Hydrogen bonds formed between the rotor and stator make the symmetric orientation of the dipole unstable. The rotor has two potential minima with equal energy for rotation about the sigma bond. The dipole orientation, which determines the conduction state of the molecule, can be switched by an external electric field that changes the relative energy of the two potential minima. Both orientation of the rotor correspond to asymmetric current-voltage characteristics that are the reverse of each other, so they are distinguishable electrically. Such bistable stator-rotor molecules could potentially be used as parts of molecular electronic devices.Comment: 8 pages, 7 figure

The first WASP public data release

The WASP (wide angle search for planets) project is an exoplanet transit survey that has been automatically taking wide field images since 2004. Two instruments, one in La Palma and the other in South Africa, continually monitor the night sky, building up light curves of millions of unique objects. These light curves are used to search for the characteristics of exoplanetary transits. This first public data release (DR1) of the WASP archive makes available all the light curve data and images from 2004 up to 2008 in both the Northern and Southern hemispheres. A web interface () to the data allows easy access over the Internet. The data set contains 3 631 972 raw images and 17 970 937 light curves. In total the light curves have 119 930 299 362 data points available between them

Understanding and informing decisions on Sustainable Agricultural Intensification in Sub-Saharan Africa

Sustainable Agricultural Intensification (SAI) was initially defined as increasing agricultural production without adverse environmental impacts and without increasing the area under agriculture. Overtime the concept has been broadened to integrate social, economic, and environmental components of sustainability, each of which covers multiple facets or indicators of performance. It is recognized however that it may not be possible to optimise all these aspects of sustainability simultaneously and that trade-offs between them are likely to occur, although synergies are also possible. There has been disagreement over how to achieve SAI, with some proposing that only an “agroecological” intensification pathway delivers sustainability. Others take a broader perspective arguing that all aspects of ecological, genetic, and socio-economic intensification need to be considered, but then assessed in terms of the sustainability of the outcomes. A major concern is that intensification that focuses on agricultural technology can lead to inequitable outcomes for women and poorer households, while agroecological intensification building upon local capitals is generally considered more equitable. Understanding the potential outcomes and inherent trade-offs of different approaches requires interdisciplinary research, evidence and decision-making tools, some examples of which are presented in this Special Issue

WASP-26b : a 1-Jupiter-mass planet around an early-G-type star

We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-mag early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A simultaneous fit to transit photometry and radial-velocity measurements yields a planetary mass of 1.02 ± 0.03 MJup and radius of 1.32 ± 0.08 RJup. The host star, WASP-26, has a mass of 1.12 ± 0.03 M and a radius of 1.34 ± 0.06 R and is in a visual double with a fainter K-type star. The two stars are at least a common-proper motion pair with a common distance of around 250 ± 15 pc and an age of 6 ± 2 Gy

The Effect of Co-feeding Methyl Acetate on the H-ZSM5 Catalysed Methanol-to-Hydrocarbons Reaction

Funding Information: Johnson Matthey plc and the EPSRC are thanked for postgraduate student support (A.P.H., A.Z.) via the Industrial CASE scheme (EP/P510506/1). Johnson Matthey plc is additionally thanked for provision of the ZSM-5 catalyst. The Science and Technology Facilities Council is thanked for the provision of neutron beam time (RB1820116, https://doi.org/10.5286/isis.e.97999822 ). The resources and support provided by the UK Catalysis Hub via Membership of the UK Catalysis Hub Consortium and funded by EPSRC (Grants EP/K014706/1, EP/K014668/1, EP/ K014854/1, EP/K014714/1, and EP/M013219/1) are gratefully acknowledged.Peer reviewedPublisher PD

SuperWASP: Wide Angle Search for Planets

SuperWASP is a fully robotic, ultra-wide angle survey for planetary transits. Currently under construction, it will consist of 5 cameras, each monitoring a 9.5 x 9.5 deg field of view. The Torus mount and enclosure will be fully automated and linked to a built-in weather station. We aim to begin observations at the beginning of 2003.Comment: 4 pages, 1 figure, to be published in proceedings of "Scientific Frontiers in Research on Extrasolar Planets

Evaluation of the Good Life Festival : a model for co-produced dementia events

The article presents an evaluation of The Good Life Festival, a co-produced event between people living with dementia, Salford University Dementia Institute, Alzheimer’s Society, Salford and Salford Adventures. This was a new way of working but important because people living with dementia said they thought there should be an event organised ‘for people with dementia by people with dementia’. A dementia friendly evaluation form was circulated asking: did you enjoy the event, did you learn something new, and do you feel more positive about living with dementia following the event. Thirty five of the eighty people who attended completed the evaluation form all of whom said they enjoyed it. 32 (91%) learned something new, and 27 (77%) left feeling more positive about living with dementia. Qualitative feedback is also included in this article including planning group reflections. Recommendations based on what we learned from planning and running the event are provided which includes having a media strategy in place and to send a follow up letter to remind people of information about resources/services advertised on the da