CU Virginis - The First Stellar Pulsar

CU Virginis is one of the brightest radio emitting members of the magnetic chemically peculiar (MCP) stars and also one of the fastest rotating. We have now discovered that CU Vir is unique among stellar radio sources in generating a persistent, highly collimated, beam of coherent, 100% polarised, radiation from one of its magnetic poles that sweeps across the Earth every time the star rotates. This makes the star strikingly similar to a pulsar. This similarity is further strengthened by the observation that the rotating period of the star is lengthening at a phenomenal rate (significantly faster than any other astrophysical source - including pulsars) due to a braking mechanism related to its very strong magnetic field.Comment: 10 pages including 2 figure

The Chandrayaan-1 X-ray spectrometer

The Chandrayaan-1 X-ray Spectrometer (C1XS) is a compact X-ray spectrometer for the Chandrayaan-1 lunar mission. It exploits heritage from the D-C1XS instrument on ESA’s SMART-1 mission. C1XS is designed to measure absolute and relative abundances of major rock-forming elements (principally Mg, Al, Si, Ti, Ca and Fe) over the lunar surface. The baseline design consists of 24 nadir pointing Swept Charge Device detectors, which provide high detection efficiency in the 1–7 keV range, which contains the X-ray fluorescence lines of the above elements of interest. Micromachined collimators provide a 14 degree FWHM FOV, equivalent to 25 km from 100 km altitude. A deployable door protects the instrument during launch and cruise, and also provides a 55Fe calibration X-ray source for detector calibration. Additional refinements compared to D-C1XS will result in a significantly improved energy resolution. To record the incident solar X-ray flux at the Moon, C1XS carries an X-ray Solar Monitor (XSM). C1XS will arrive at the Moon in the run up to the maximum of the solar cycle 24, and the expected high incident X-ray flux coupled to a 100 km circular polar orbit, will provide composition data accurate to better than 10% of major elemental abundances over the lunar surface

Results from the CERN pilot CLOUD experiment

During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm -3 s -1, and growth rates between 2 and 37 nm h -1. The corresponding H2O concentrations were typically around 106 cm -3 or less. The experimentally-measured formation rates and htwosofour concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C

Is there still a place for Achilles tendon lengthening?

Patients with diabetes and ankle equinus are at particularly high risk for forefoot ulceration because of the development of high forefoot pressures. Stiffness in the triceps surae muscles and tendons are thought to be largely responsible for equinus in patients with diabetes and underpins the surgical rationale for Achilles tendon lengthening (ATL) procedures to alleviate this deformity and reduce ulcer risk. The established/traditional surgical approach is the triple hemisection along the length of the Achilles tendon. Although the percutaneous approach has been successful in achieving increases in ankle dorsiflexion >30°, the tendon rupture risk has led to some surgeons looking at alternative approaches. The gastrocnemius aponeurosis may be considered as an alternative because of the Achilles tendon’s poor blood supply. ATL procedures are a balance between achieving adequate tendon lengthening and minimizing tendon rupture risk during or after surgery. After ATL surgery, the first 7 days should involve reduced loading and protected range of motion to avoid rupture, after which gradual reintroduction to loading should be encouraged to increase tendon strength. In summary, there is a moderate level of evidence to support surgical intervention for ankle joint equinus in patients with diabetes and forefoot ulceration that is non-responsive to other conservative treatments. Areas of caution for ATL procedures include the risk for overcorrection, tendon rupture and the tendon’s poor blood supply. Further prospective randomized control trials are required to confirm the benefits of ATL procedures over conservative care and the most optimal anatomical sites for surgical intervention.

Cellular Prion Protein Expression Is Not Regulated by the Alzheimer's Amyloid Precursor Protein Intracellular Domain

There is increasing evidence of molecular and cellular links between Alzheimer's disease (AD) and prion diseases. The cellular prion protein, PrPC, modulates the post-translational processing of the AD amyloid precursor protein (APP), through its inhibition of the β-secretase BACE1, and oligomers of amyloid-β bind to PrPC which may mediate amyloid-β neurotoxicity. In addition, the APP intracellular domain (AICD), which acts as a transcriptional regulator, has been reported to control the expression of PrPC. Through the use of transgenic mice, cell culture models and manipulation of APP expression and processing, this study aimed to clarify the role of AICD in regulating PrPC. Over-expression of the three major isoforms of human APP (APP695, APP751 and APP770) in cultured neuronal and non-neuronal cells had no effect on the level of endogenous PrPC. Furthermore, analysis of brain tissue from transgenic mice over-expressing either wild type or familial AD associated mutant human APP revealed unaltered PrPC levels. Knockdown of endogenous APP expression in cells by siRNA or inhibition of γ-secretase activity also had no effect on PrPC levels. Overall, we did not detect any significant difference in the expression of PrPC in any of the cell or animal-based paradigms considered, indicating that the control of cellular PrPC levels by AICD is not as straightforward as previously suggested

Improving mental health and reducing antipsychotic use in people with dementia in care homes: the WHELD research programme including two RCTs

BackgroundThe effective management of agitation and other neuropsychiatric and behavioural symptoms in people with dementia is a major challenge, particularly in care home settings, where dementia severity is higher and there is limited training and support for care staff. There is evidence for the value of staff training and the use of psychosocial approaches; however, no intervention currently exists that combines these elements into an intervention that is fit for purpose and effective in these settings based on evidence from a randomised controlled trial.ObjectiveThe objective was to develop and evaluate a complex intervention to improve well-being, reduce antipsychotic use and improve quality of life in people with dementia in care homes through person-centred care, management of agitation and non-drug approaches.DesignThis was a 5-year programme that consisted of six work packages. Work package 1 consisted of two systematic reviews of personalised psychosocial interventions for behavioural and psychological symptoms for people with dementia in care homes. Work package 2 consisted of a metasynthesis of studies examining implementation of psychosocial interventions, in addition to developing a draft Well-being and Health for people with Dementia (WHELD) programme. Work package 3 consisted of a factorial study of elements of the draft WHELD programme in 16 care homes. Work package 4 involved optimisation of the WHELD programme based on work package 3 data. Work package 5 involved a multicentre randomised controlled trial in 69 care homes, which evaluated the impact of the optimised WHELD programme on quality of life, agitation and overall neuropsychiatric symptoms in people with dementia. Work package 6 focused on dissemination of the programme.SettingThis programme was carried out in care homes in the UK.ParticipantsParticipants of this programme were people with dementia living in care homes, and the health and care professionals providing treatment and care in these settings.ResultsWork package 1: reviews identified randomised controlled trials and qualitative evidence supporting the use of psychosocial approaches to manage behavioural symptoms, but highlighted a concerning lack of evidence-based training manuals in current use. Work package 2: the meta-analysis identified key issues in promoting the use of interventions in care homes. The WHELD programme was developed through adaptation of published approaches. Work package 3: the factorial trial showed that antipsychotic review alone significantly reduced antipsychotic use by 50% (odds ratio 0.17, 95% confidence interval 0.05 to 0.60). Antipsychotic review plus social interaction significantly reduced mortality (odds ratio 0.36, 95% confidence interval 0.23 to 0.57), but this group showed significantly worse outcomes in behavioural and psychological symptoms of dementia than the group receiving neither antipsychotic review nor social interaction (mean difference 7.37 symptoms, 95% confidence interval 1.53 to 13.22 symptoms). This detrimental impact was reduced when combined with social interaction (mean difference –0.44 points, 95% confidence interval –4.39 to 3.52 points), but with no significant benefits for agitation. The exercise intervention significantly improved neuropsychiatric symptoms (mean difference –3.58 symptoms, 95% confidence interval –7.08 to –0.09 symptoms) but not depression (mean difference –1.21 points, 95% confidence interval –4.35 to 1.93 points). Qualitative work with care staff provided additional insights into the acceptability and feasibility of the intervention. Work package 4: optimisation of the WHELD programme led to a final version that combined person-centred care training with social interaction and pleasant activities. The intervention was adapted for delivery through a ‘champion’ model. Work package 5: a large-scale, multicentre randomised controlled trial in 69 care homes showed significant benefit to quality of life, agitation and overall neuropsychiatric symptoms, at reduced overall cost compared with treatment as usual. The intervention conferred a statistically significant improvement in quality of life (Dementia Quality of Life Scale – Proxy z-score of 2.82, mean difference 2.54, standard error of measurement 0.88, 95% confidence interval 0.81 to 4.28, Cohen’s d effect size of 0.24; p = 0.0042). There were also statistically significant benefits in agitation (Cohen-Mansfield Agitation Inventory z-score of 2.68, mean difference –4.27, standard error of measurement 1.59, 95% confidence interval –7.39 to –1.15, Cohen’s d effect size of 0.23; p = 0.0076) and overall neuropsychiatric symptoms (Neuropsychiatric Inventory – Nursing Home version z-score of 3.52, mean difference –4.55, standard error of measurement 1.28, 95% confidence interval –7.07 to –2.02, Cohen’s d of 0.30; p

Late Cretaceous–earliest Paleogene deformation in the Longmen Shan fold-and-thrust belt, eastern Tibetan Plateau margin: pre-Cenozoic thickened crust?

This study presents structural and 40Ar/39Ar geochronological data from the southern part of the Longmen Shan fold-and-thrust belt that forms the eastern margin of the Tibetan Plateau. Investigations focused on hinterland ductile top-to-the-WNW shear deformation, which has been linked previously to late Cenozoic lower crustal flow. Consistent with previous studies, the sense of deformation is mapped as top-to-the-WNW in the Longmen Shan hinterland. The timing of the deformation is constrained by 40Ar/39Ar geochronological data of recrystallized minerals aligned along the shear foliation as Late Cretaceous–earliest Paleogene, thus predating the inferred late Cenozoic crustal flow. This deformation is contemporaneous with SE verging thrusting and loading along the Longmen Shan front, which formed a coeval ~2–3 km thick foredeep sequence along the southwestern margin of the Sichuan Basin. In the context of the regional geology, this tectonic configuration could result from either extrusion of a crustal wedge or back thrust in a duplex. Compared to other orogens, where similar crustal configurations have been reported, it is speculated that the eastern Tibetan Plateau margin acquired thickened crust and highly elevated topography in Late Cretaceous–earliest Paleogene time

RE 0044+09: A new K dwarf rapid rotator with a white dwarf companion?

We report the discovery of a new K dwarf rapid rotator with a potential white dwarf companion. The white dwarf accounts for over 90% of the observed extreme ultraviolet flux detected from this system. Analysis of ROSAT Wide Field Camera (WFC) and IUE data both suggest a white dwarf temperature of approximately 28,700 K. Optical photometry and the IUE long wavelength prime (LWP) spectrum (with the white dwarf contribution removed) imply that the late-type star has a spectral type of K1-3 V, and a distance of 55 +/- 5 pc. Using this distance, the observed IUE SWP flux, and the best-fit temperature results in a white dwarf radius of 0.0088 solar radius. The estimated white dwarf mass is then approximately 0.91 solar mass; somewhat over-massive compared to field white dwarfs. Optical photometry of the K star reveals a 'spot' modulation period of approximately 10 hr (now observed over 3 yr). However, radial velocity observations have revealed no significant variations. Spectroscopic observations place a low limit on the lithium abundance, but do show rapid rotation with a v sin i of 90 +/- 10 km/s. The K star was detected as a radio source at 3.6 cm (on two occasions) and 6 cm by the Very Large Array (VLA). The most likely evolutionary scenario is that the K star and hot white dwarf from either a wide binary or common proper motion pair with an age of 0.1-0.1 Gyr-consistent with the evolutionary timescale of the white dwarf and the rapid rotation of the K star. However, from the proper motion of the K star, this system does not seem to be associated with any of the known young stellar groups