A two-species continuum model for aeolian sand ripples

We formulate a continuum model for aeolian sand ripples consisting of two species of grains: a lower layer of relatively immobile clusters, with an upper layer of highly mobile grains moving on top. We predict analytically the ripple wavelength, initial ripple growth rate and threshold saltation flux for ripple formation. Numerical simulations show the evolution of realistic ripple profiles from initial surface roughness via ripple growth and merger.Comment: 9 pages, 3 figure

Does increasing packing density using larger caliber coils improve angiographic results of embolization of intracranial aneurysms at 1 year: A randomized trial

© 2020 American Society of Neuroradiology. All rights reserved. BACKGROUND AND PURPOSE: The impact of increased aneurysm packing density on angiographic outcomes has not been studied in a randomized trial. We sought to determine the potential for larger caliber coils to achieve higher packing densities and to improve the angiographic results of embolization of intracranial aneurysms at 1 year. MATERIALS AND METHODS: Does Embolization with Larger Coils Lead to Better Treatment of Aneurysms (DELTA) was an investigator-initiated multicenter prospective, parallel, randomized, controlled clinical trial. Patients had 4- to 12-mm unruptured aneurysms. Treatment allocation to either 15- (experimental) or 10-caliber coils (control group) was randomized 1:1 using a Web-based platform. The primary efficacy outcome was a major recurrence or a residual aneurysm at follow-up angiography at 12 6 2 months adjudicated by an independent core lab blinded to the treatment allocation. Secondary outcomes included indices of treatment success and standard safety outcomes. Recruitment of 564 patients was judged necessary to show a decrease in poor outcomes from 33% to 20% with 15-caliber coils. RESULTS: Funding was interrupted and the trial was stopped after 210 patients were recruited between November 2013 and June 2017. On an intent-to-treat analysis, the primary outcome was reached in 37 patients allocated to 15-caliber coils and 36 patients allocated to 10-caliber coils (OR = 0.931; 95% CI, 0.528–1.644; P = .885). Safety and other clinical outcomes were similar. The 15-caliber coil group had a higher mean packing density (37.0% versus 26.9%, P = .0001). Packing density had no effect on the primary outcome when adjusted for initial angiographic results (OR = 1.001; 95% CI, 0.981–1.022; P = .879). CONCLUSIONS: Coiling of aneurysms randomized to 15-caliber coils achieved higher packing densities compared with 10-caliber coils, but this had no impact on the angiographic outcomes at 1 year, which were primarily driven by aneurysm size and initial angiographic results

Efficacy and Safety Comparison of Liraglutide, Glimepiride, and Placebo, All in Combination With Metformin, in Type 2 Diabetes: The LEAD (Liraglutide Effect and Action in Diabetes)-2 study

OBJECTIVE—The efficacy and safety of adding liraglutide (a glucagon-like peptide-1 receptor agonist) to metformin were compared with addition of placebo or glimepiride to metformin in subjects previously treated with oral antidiabetes (OAD) therapy

British citizenship, gender and migration: the containment of cultural differences and the stratification of belonging

Debates about integration, British values and identity, who can belong and who can become a citizen, have been fuelled by concerns about growing cultural diversity in the United Kingdom. To promote a shared sense of national identity and claim a universal and normative citizen subject, the UK government, along with many other western nations, has introduced compulsory citizenship and language testing. This article traces and critiques the evolution of the British citizenship test since its introduction in 2005 and argues that the regime fails to recognise the gendered and segmented nature of migration, and functions as a silent and largely invisible mechanism of civic stratification and control. Drawing on Home Office data, it is argued that citizenship testing enables the government to cherry pick migrants who conform to an idealised citizen subject, while containing cultural difference by excluding others, particularly women, who are tolerated but remain symbolic non-citizens

Over-prescription of short-acting β2-agonists for asthma in South Africa: Results from the SABINA III study

Background. Asthma medication prescription trends, including those of short-acting β2-agonists (SABAs), are not well documented for South Africa (SA). Objectives. To describe demographics, disease characteristics and asthma prescription patterns in the SA cohort of the SABA use IN Asthma (SABINA) III study. Methods. An observational, cross-sectional study conducted at 12 sites across SA. Patients with asthma (aged ≥12 years) were classified by investigator-defined asthma severity, guided by the Global Initiative for Asthma (GINA) 2017 recommendations, and practice type (primary/ specialist care). Data were collected using electronic case report forms. Results. Overall, 501 patients were analysed − mean (standard deviation) age, 48.4 (16.6) years; 68.3% female − of whom 70.6% and 29.4% were enrolled by primary care physicians and specialists, respectively. Most patients were classified with moderate-to-severe asthma (55.7%; GINA treatment steps 3 - 5), were overweight or obese (70.7%) and reported full healthcare reimbursement (55.5%). Asthma was partly controlled/uncontrolled in 60.3% of patients, with 46.1% experiencing ≥1 severe exacerbations in the 12 months before the study visit. Overall, 74.9% of patients were prescribed ≥3 SABA canisters in the previous 12 months (over-prescription); 56.5% were prescribed ≥10 SABA canisters. Additionally, 27.1% of patients reported purchasing SABA over-the-counter (OTC); among patients with both SABA purchase and prescriptions, 75.4% and 51.5% already received prescriptions for ≥3 and ≥10 SABA canisters, respectively, in the preceding 12 months. Conclusion. SABA over-prescription and OTC purchase were common in SA, demonstrating an urgent need to align clinical practices with the latest evidence-based recommendations and regulate SABA OTC purchase to improve asthma outcomes

A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Epitaxy

ABSTRACT Step-doped structures of both magnesium and beryllium were grown in GaN and analyzed using secondary ion mass spectrometry. Dopant incorporation was studied as a function of substrate temperature and dopant flux for Ga-polarity and N-polarity GaN. Incorporation is different for each polarity, with Mg incorporating by up to a factor of 20 times more (30 times more with atomic hydrogen) on the Ga-face, while Be incorporates more readily on the N-face. The effect of atomic hydrogen on the incorporation kinetics of both Mg and Be is also discussed. Mg and Be both undergo surface segregation during growth. Photoluminescence measurements suggest that Be is a p-type dopant with an optical activation energy of approximately 100 meV

A modified footplate for the Kerrison rongeur

Use of the Kerrison rongeur for bone removal in spinal surgery is associated with dural tears and cerebrospinal fluid (CSF) leaks. We report a modification of the Kerrison rongeur footplate designed to reduce the risk of dural tears. A novel footplate was designed by incorporating the following parameters: (1) tapering the footplate to deflect soft tissue downward during positioning of the rongeur underneath the bone, and (2) making the footplate longer and wider than the cutting element to prevent soft tissue from entering into the cutting surface. Stereolithography models of the modified footplate were made and tested in a cadaver. A stainless steel modified footplate was then incorporated into an existing Kerrison rongeur as a working prototype, and tested in 20 laminectomy cases to clinically validate its design. The modified footplate prevented soft tissue from entering the cutting surface of the Kerrison rongeur in the manner intended by its design. No dural tears or CSF leaks were encountered in any instance. Potential soft tissue compression caused by an increase in footplate dimensions was not a significant issue in the rongeur size tested. This modification, however, might not be practical in rongeurs larger than 3 mm. The risk of dural tears and cerebrospinal fluid leaks in spinal surgery may be reduced by this footplate modification of the Kerrison rongeur. Soft tissue compression may limit the incorporation of this modification to rongeurs of 3 mm or smaller. The promising results warrant further tests with a wider range of sizes.Center for Integration of Medicine and Innovative Technology (U.S. Army Medical Research Acquisition Activity Cooperative Agreement No. DAMD17-02-2-0006