Four lectures on secant varieties

This paper is based on the first author's lectures at the 2012 University of Regina Workshop "Connections Between Algebra and Geometry". Its aim is to provide an introduction to the theory of higher secant varieties and their applications. Several references and solved exercises are also included.Comment: Lectures notes to appear in PROMS (Springer Proceedings in Mathematics & Statistics), Springer/Birkhause

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Optical observations of comets

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN031249 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

CCD photometry of distant comets

While it is apparent that many comets are active beyond the canonical distance of 3 AU, few surveys of cometary activity have been performed in this region previously. Such a survey enables a more accurate determination of the proportion of comets that exhibit little or no outgassing at these distances. Results are presented of CCD observations of comets in the region of 3 AU < Rh < 6 AU obtained with the 1m JKT on La Palma. Photometric observations of 15 comets were obtained, 7 of which displayed coma activity and 8 of which appeared inactive. BVR photometry was performed on these comets to determine dimensions, colours and outgassing rates. Although 40P/VaisaIa 1 and 26P/Grigg-Skjellerup were not detected, upper limits to their nuclear radii are presented. The results obtained are compared with previous observations

Emission dynamics of red emitting InGaN/GaN single quantum wells

Emission dynamics of two InGaN/GaN single quantum well red emitters were investigated through time-resolved photoluminescence (PL) spectroscopy. A clear phase separation, where a higher energy (blue) emission and a lower energy (red) emission appear simultaneously, was observed. The maximum position of blue emission is consistent with the bandgap value of the InGaN quantum well. As the time after pulsed excitation increases, the higher energy emission decreased more rapidly than that of the lower energy emission. In addition, the temperature dependence of the peak position of lower energy emission showed an initial redshift followed by a blueshift, reflecting the thermal distribution and transfer of localized carriers within different potential minima