Micromagnetic Domain Structures in Cylindrical Nickel Dots

The magnetic domain structures of cylindrical nickel dots (diameters from 40 nm to 1700 nm) with anisotropy parallel to the cylinder axis is predicted by the ratio of the dot diameter to the stripe period of unpatterned films with the same perpendicular anisotropy. The dominant domain structure for a given ratio increases in complexity as the ratio increases. We present evidence for the full micromagnetic domain structure for the simplest cases

Willamette Valley-PugetTrough-Georgia Basin ecoregional assessment

This assessment is intended to help conservation agencies, planners and organizations direct their resources to the most important places for supporting the ecoregion's biodiversity.Keywords: Puget Trough ecoregion, Georgia Basin ecoregion, Willamette Valley ecoregio

Populist Mobilization: A New Theoretical Approach to Populism*

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112280/1/j.1467-9558.2011.01388.x.pd

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Draft Evolution of the Complexity of Magnetic Domain Structure in Nano-Scale Nickel Particles

The micromagnetic structure of nanofabricated nickel particles has been determined as a function of particle diameter and thickness using a combination of high-resolution magnetic force microscopy and Landau-Lifshitz-Gilbert micromagnetic simulations. Cylindrical particles were lithographically prepared with diameters in the range 68- 900 nm, and thickness between 48 and 140 nm. Extensive measurements and simulations of the 100 nm thick cylinders are reported in this note. At this thickness, the complexity of observed magnetic states increases as the particle diameter increases. Single domain structures are found at the smallest diameters, with two- and three-domain structures appearing at larger diameters, characterized by in-plane vorticity and in the simplest case, a vortex ring. At diameters greater than at least 360 nm, the magnetic structure is composed of random stripe domains very similar to those found in nickel films of the same thickness

Surface Using Si/Ge/Sn-Based Dimer Placement Tools

This paper extends an ongoing computational and theoretical investigation of the vacuum mechanosynthesis of diamond on a clean C(110) diamond surface from carbon dimer (C2) precursors, using Si-, Ge-, and Sn-substituted triadamantane-based positionally-controlled DCB6 dimer placement tools. Interactions between the dimer placement tools and the C(110) surface are investigated by means of stepwise ab initio molecular dynamics (AIMD) simulations, using Density Functional Theory (DFT) with generalized gradient approximation (GGA), implemented in the VASP software package. The Ge-based tool tip provides better functionality over a wider range of temperatures and circumstances (as compared with the Si or Sn tool tips). The transfer of a single carbon dimer from the Si-based tool tip onto C(110) is not controllable at 300 K but is workable at 80 K; the Ge-based tool remains workable up to 300 K. Geometry optimization suggests the Sn-based tool deposits reliably but the discharged tool is distorted after use; stepwise AIMD retraction simulations (at 300 K for the Sn tip) showed tip distortion with terminating Sn atoms prone to being attracted towards the surface carbon atoms. Stepwise AIMD shows successful placement of a second dimer in a 1-dimer gapped position, and successful intercalation of a third dimer into the 1-dimer gap between two previously deposited dimers, on clean C(110) at 300 K using the G