3,106 research outputs found

    Evaluation of Recurrence Risks for Left-Sided Cardiac Lesions

    Get PDF
    It is widely accepted that hypoplastic left heart syndrome (HLHS), aortic valve stenosis with or without bicuspid aortic valve (AS/BAV) and coarctation of the aorta (CoA) occur in families more commonly with each other than with any other congenital heart defect (CHD). Genetic counseling for CHDs is currently based on empiric risk estimates derived from data collected on all types of CHDs between 1968 and 1990. Additionally, for the specific group of defects described above, termed left-sided lesions, estimates are available for sibling recurrence. Utilizing family history data from 757 probands recruited between 1997 and 2007 from The Children’s Hospital of Philadelphia, this study reassessed the pre/recurrence risks for LSLs specifically. Sibling pre/recurrence risks for HLHS (5.5%, 95% CI: 3.1%-8.9%), CoA (4.0%, 95% CI: 2.1%-6.7%), and AS/BAV (6.0%, 95% CI: 3.3%-9.8%) were higher than currently quoted risks based on sibling data for individual LSLs. Additionally, the prevalence of BAV in 202, apparently unaffected, parents of 134 probands was assessed by echocardiography. BAV, which occurs at a frequency of 1% in the general population, was found to occur in approximately 10% of parents of LSL probands. Lastly, among affected first-degree relative pairs (i.e. siblings, parent-offspring), the majority (65%-70%) were both affected with a LSL. Defect specific concordance rates were highest for AS/BAV. Together, these findings suggest that over the past 20 years with changing diagnostic capabilities and environmental/maternal conditions (e.g. folic acid fortification, increased maternal diabetes and obesity) recurrence risks may have increased, as compared to current LSL specific risk estimates. Based on these risk estimate increases and prior studies, a protocol for screening first-degree relatives of LSL probands should be devised

    Global strategic partnerships to share international and local expertise between private sector and NGOs

    Get PDF
    The term ‘partnership’ can cover a wide range of relationships between different types of organisations. However, genuine partnerships between the private and NGO sectors are still relatively uncommon. The global consultancy firm Arup has developed a number of partnerships with NGOs in the water sector to bring international expertise to help solve local problems. This paper briefly reviews the partnership context and describes two water projects – one in Bangladesh and one in Ghana - where Arup staff have worked with local NGOs to develop locally appropriate solutions to technical problems. The paper explores the mutual benefits that both organisations can enjoy from this type of partnership

    The Implications of M Dwarf Flares on the Detection and Characterization of Exoplanets at Infrared Wavelengths

    Full text link
    We present the results of an observational campaign which obtained high time cadence, high precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hours. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to milli-magnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of ~7.8x10^30 to ~1.3x10^32 ergs, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a ~1.3x10^32 erg U-band flare (delta Umax ~1.5 mag) will induce <8.3 (J), <8.5 (H), and <11.7 (Ks) milli-mags of a response. A flare of this energy or greater should occur less than once per 18 hours. For active dM4.5e stars, we find that a ~5.1x10^31 erg U-band flare (delta Umax ~1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) milli-mags of a response. A flare of this energy or greater should occur less than once per 10 hours. No evidence of stellar variability not associated with discrete flare events was observed at the level of ~3.9 milli-mags over 1 hour time-scales and at the level of ~5.6 milli-mags over 7.5 hour time-scales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of ~5-11 milli-mags, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of milli-mags.Comment: Accepted in Astronomical Journal, 17 pages, 6 figure

    Huntington's disease patients display progressive deficits in hippocampal-dependent cognition during a task of spatial memory.

    Get PDF
    BACKGROUND: Cognitive disturbances occur early in Huntington's disease (HD) and place a significant burden on the lives of patients and family members. Whilst these impairments are typically attributed to deterioration of the frontal-striatal pathways, accumulating evidence suggests that hippocampal dysfunction may also contribute to such impairments. Here, we employ a novel spatial memory task that has previously been shown to elicit impairments in individuals with focal hippocampal lesions, as a means to further investigate the role of hippocampal dysfunction in HD. METHOD: Sixty-four individuals participated in the study, including 32 healthy controls, 11 patients with diagnosed HD and 16 premanifest HD gene carriers. We also included an additional control group of 5 individuals with focal unilateral basal ganglia lesions. Participants undertook a task that measured perception and short-term spatial memory using computer-generated visual scenes. RESULTS: HD patients experienced significant impairments in spatial perception and memory, which strongly correlated with disease burden score (DBS). Premanifest gene carriers performed at a similar level to healthy controls throughout all aspects of the task indicating that the effects seen in the HD patients represent a deterioration in function. Interestingly, basal ganglia lesion patients were not impaired in any aspects of the task. CONCLUSION: There is evidence of significant deficits in hippocampal-dependent spatial cognition in HD that cannot be explained as a function of degeneration to the basal ganglia. The impairments were greatest in individuals with higher DBSs, suggesting that deficits relate to the disease process in HD

    Can a Purposeful Walk Intervention with a Distance Goal using a Commercially Available Activity Monitor Improve Individuals' daily activity and function Post Total Hip Replacement Surgery - A Randomised Pilot Trial

    Get PDF
    Individuals have increasingly high expectations of return to activity following Total Hip Replacement surgery. The current literature demonstrates marked improvements in pain following THR. However, there is limited evidence showing objective improvement in daily activity. This randomised pilot trial aimed to determine the effect of an intervention where outdoor walking distance is used as a goal to increase daily activity of older adults using a commercial activity monitor at 3 to 6 months post THR. Findings suggested that the participants in the intervention group had higher activity levels after THR, compared to those in the control group. The Cohen’s effect sizes were larger for the changes in the gait, Hip Disability and Osteoarthritis Outcome Score, and Psychosocial Impact of Assistive Devices Scale data in the intervention group in contrast to the control group. However, further research with a larger sample size is required to provide tangible evidence on the significance of the effect of the purposeful walk compared to step count

    A feasibility study to evaluate a purposeful walk intervention with a distance goal using a commercially available activity monitor in elderly people post total hip replacement surgery

    Get PDF
    Introduction Total hip replacement (THR) is performed in an increasing number of individuals around the world and while improvements in pain reduction and long-term enhancement of muscle strength are well documented, the improvement in daily activity does not follow the same trend. This study aimed to determine the feasibility of a 5-week intervention where a personalised outdoor walking distance is monitored using a commercial activity monitor (Fitbit Charge 4). Method Data was collected on gait and activities of daily living using patient reported outcome measures. Following the completion of the intervention period, participants took part in a semi-structured interview to voice their opinion on the use of the activity monitor, their experiences, and any challenges in order to assess the feasibility of the intervention. All quantitative data were presented descriptively, using appropriate summary statistics. Interviews were analysed using thematic analysis. Results Five participants who had undergone total hip replacement surgery within the postoperative period of 3 to 6 months were recruited from the local community. Conclusion The findings suggest that the intervention was feasible and that it encouraged all participants to increase their daily activity. Therefore, it can be concluded that a follow-up effectiveness trial is warranted

    Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b

    Get PDF
    The nearby extrasolar planet GJ 436b--which has been labelled as a 'hot Neptune'--reveals itself by the dimming of light as it crosses in front of and behind its parent star as seen from Earth. Respectively known as the primary transit and secondary eclipse, the former constrains the planet's radius and mass, and the latter constrains the planet's temperature and, with measurements at multiple wavelengths, its atmospheric composition. Previous work using transmission spectroscopy failed to detect the 1.4-\mu m water vapour band, leaving the planet's atmospheric composition poorly constrained. Here we report the detection of planetary thermal emission from the dayside of GJ 436b at multiple infrared wavelengths during the secondary eclipse. The best-fit compositional models contain a high CO abundance and a substantial methane (CH4) deficiency relative to thermochemical equilibrium models for the predicted hydrogen-dominated atmosphere. Moreover, we report the presence of some H2O and traces of CO2. Because CH4 is expected to be the dominant carbon-bearing species, disequilibrium processes such as vertical mixing and polymerization of methane into substances such as ethylene may be required to explain the hot Neptune's small CH4-to-CO ratio, which is at least 10^5 times smaller than predicted
    • …
    corecore