Driving Cessation in Patients Attending a Young-Onset Dementia Clinic: A Retrospective Cohort Study.

Background: Although driving by persons with dementia is an important public health concern, little is known about driving cessation in younger people with dementia. We aimed to determine the prevalence and factors affecting driving cessation in individuals with and without dementia aged under 65 years attending a memory clinic in a European setting. Methods: Subjects were consecutive patients assessed at a specialist memory service at a university teaching hospital between 2000 and 2010. The data collected included demographic, clinical, standardized cognitive assessments as well as information on driving. Dementia diagnosis was made using ICD-10 criteria. Results: Of the 225 people who were or had been drivers, 32/79 (41%) with young-onset dementia (YOD) stopped driving compared to 25/146 (17%) patients who had cognitive impairment due to other causes. Women were more likely to cease driving and voluntarily than men (p < 0.001). Diagnosis of YOD was associated with driving cessation (1.193, 95% CI 0.570-1.815, p ≤ 0.001), and was mediated by impairment in praxis with the highest indirect mediation effect (0.754, 95% CI 0.183-1.401, p = 0.009). Conclusions: YOD diagnosis, female gender, and impairment in praxis have a higher probability for driving cessation in those under 65 years of age with cognitive impairment

Long-term X-ray variability characteristics of the narrow-line Seyfert 1 galaxy RE J1034+396

We present the results of our study of the long-term X-ray variability characteristics of the narrow-line Seyfert 1 galaxy RE J1034+396. We use data obtained from the AstroSat satellite along with light curves obtained from XMM–Newton and Swift–XRT. We use the 0.3–7.0 keV and 3–20 keV data, respectively, from the SXT and the LAXPC of AstroSat. The X-ray spectra in the 0.3–20 keV region are well fitted with a model consisting of a power law and a soft excess described by a thermal Compton emission with a large optical depth, consistent with the earlier reported results. We have examined the X-ray light curves in the soft and hard X-ray bands of the SXT and LAXPC, respectively, and find that the variability is slightly larger in the hard band. To investigate the variability characteristics of this source at different time-scales, we have used X-ray light curves obtained from XMM–Newton data (200 s to 100 ks range) and Swift–XRT data (1 to 100 d range) and find that there is evidence to suggest that the variability increases sharply at longer time-scales. We argue that the mass of the black hole in RE J1034+396 is likely to be ∼3 × 10^6 M⊙, based on the similarity of the observed quasi-periodic oscillation (QPO) to the high-frequency QPO seen in the galactic black hole binary GRS 1915+105

Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants

The local Cosmic Ray (CR) energy spectrum exhibits a spectral softening at energies around 3 PeV. Sources which are capable of accelerating hadrons to such energies are called hadronic PeVatrons. However, hadronic PeVatrons have not yet been firmly identified within the Galaxy. Several source classes, including Galactic Supernova Remnants (SNRs), have been proposed as PeVatron candidates. The potential to search for hadronic PeVatrons with the Cherenkov Telescope Array (CTA) is assessed. The focus is on the usage of very high energy γ-ray spectral signatures for the identification of PeVatrons. Assuming that SNRs can accelerate CRs up to knee energies, the number of Galactic SNRs which can be identified as PeVatrons with CTA is estimated within a model for the evolution of SNRs. Additionally, the potential of a follow-up observation strategy under moonlight conditions for PeVatron searches is investigated. Statistical methods for the identification of PeVatrons are introduced, and realistic Monte-Carlo simulations of the response of the CTA observatory to the emission spectra from hadronic PeVatrons are performed. Based on simulations of a simplified model for the evolution for SNRs, the detection of a γ-ray signal from in average 9 Galactic PeVatron SNRs is expected to result from the scan of the Galactic plane with CTA after 10 h of exposure. CTA is also shown to have excellent potential to confirm these sources as PeVatrons in deep observations with O(100) hours of exposure per source.</p