Nano-Sim: A Step Wise Equivalent Conductance based Statistical Simulator for Nanotechnology Circuit Design

New nanotechnology based devices are replacing CMOS devices to overcome CMOS technology's scaling limitations. However, many such devices exhibit non-monotonic I-V characteristics and uncertain properties which lead to the negative differential resistance (NDR) problem and the chaotic performance. This paper proposes a new circuit simulation approach that can effectively simulate nanotechnology devices with uncertain input sources and negative differential resistance (NDR) problem. The experimental results show a 20-30 times speedup comparing with existing simulators.Comment: Submitted on behalf of EDAA (http://www.edaa.com/

Propagation of the 2012 March Coronal Mass Ejections from the Sun to Heliopause

In 2012 March the Sun exhibited extraordinary activities. In particular, the active region NOAA AR 11429 emitted a series of large coronal mass ejections (CMEs) which were imaged by STEREO as it rotated with the Sun from the east to west. These sustained eruptions are expected to generate a global shell of disturbed material sweeping through the heliosphere. A cluster of shocks and interplanetary CMEs (ICMEs) were observed near the Earth, and are propagated outward from 1 AU using an MHD model. The transient streams interact with each other, which erases memory of the source and results in a large merged interaction region (MIR) with a preceding shock. The MHD model predicts that the shock and MIR would reach 120 AU around 2013 April 22, which agrees well with the period of radio emissions and the time of a transient disturbance in galactic cosmic rays detected by Voyager 1. These results are important for understanding the "fate" of CMEs in the outer heliosphere and provide confidence that the heliopause is located around 120 AU from the Sun.Comment: 13 pages, 5 figures, accepted for publication in ApJ Letter

On Sun-to-Earth Propagation of Coronal Mass Ejections: 2. Slow Events and Comparison with Others

As a follow-up study on Sun-to-Earth propagation of fast coronal mass ejections (CMEs), we examine the Sun-to-Earth characteristics of slow CMEs combining heliospheric imaging and in situ observations. Three events of particular interest, the 2010 June 16, 2011 March 25 and 2012 September 25 CMEs, are selected for this study. We compare slow CMEs with fast and intermediate-speed events, and obtain key results complementing the attempt of \citet{liu13} to create a general picture of CME Sun-to-Earth propagation: (1) the Sun-to-Earth propagation of a typical slow CME can be approximately described by two phases, a gradual acceleration out to about 20-30 solar radii, followed by a nearly invariant speed around the average solar wind level, (2) comparison between different types of CMEs indicates that faster CMEs tend to accelerate and decelerate more rapidly and have shorter cessation distances for the acceleration and deceleration, (3) both intermediate-speed and slow CMEs would have a speed comparable to the average solar wind level before reaching 1 AU, (4) slow CMEs have a high potential to interact with other solar wind structures in the Sun-Earth space due to their slow motion, providing critical ingredients to enhance space weather, and (5) the slow CMEs studied here lack strong magnetic fields at the Earth but tend to preserve a flux-rope structure with axis generally perpendicular to the radial direction from the Sun. We also suggest a "best" strategy for the application of a triangulation concept in determining CME Sun-to-Earth kinematics, which helps to clarify confusions about CME geometry assumptions in the triangulation and to improve CME analysis and observations.Comment: 37 pages, 13 figures, accepted for publication in ApJ Supplemen

Sun-to-Earth Characteristics of Two Coronal Mass Ejections Interacting near 1 AU: Formation of a Complex Ejecta and Generation of a Two-Step Geomagnetic Storm

On 2012 September 30 - October 1 the Earth underwent a two-step geomagnetic storm. We examine the Sun-to-Earth characteristics of the coronal mass ejections (CMEs) responsible for the geomagnetic storm with combined heliospheric imaging and in situ observations. The first CME, which occurred on 2012 September 25, is a slow event and shows an acceleration followed by a nearly invariant speed in the whole Sun-Earth space. The second event, launched from the Sun on 2012 September 27, exhibits a quick acceleration, then a rapid deceleration and finally a nearly constant speed, a typical Sun-to-Earth propagation profile for fast CMEs \citep{liu13}. These two CMEs interacted near 1 AU as predicted by the heliospheric imaging observations and formed a complex ejecta observed at Wind, with a shock inside that enhanced the pre-existing southward magnetic field. Reconstruction of the complex ejecta with the in situ data indicates an overall left-handed flux rope-like configuration, with an embedded concave-outward shock front, a maximum magnetic field strength deviating from the flux rope axis and convex-outward field lines ahead of the shock. While the reconstruction results are consistent with the picture of CME-CME interactions, a magnetic cloud-like structure without clear signs of CME interactions \citep{lugaz14} is anticipated when the merging process is finished.Comment: 15 pages, 5 figures. Accepted for publication in ApJ Letter

Examining Digital Inequities in Ohio’s K-12 Virtual Schools: Implications for Educational Leaders and Policymakers

One touted purpose of virtual schools is to expand learning opportunities for students, but in reality, virtual schooling may not be readily available to all students. This study analyzes inequitable access to Ohio’s virtual schooling by examining disaggregated student enrollment data. Similar to past research, we found racial minorities and students with limited English proficiency were under-represented in Ohio’s virtual schools in comparison to traditional schools. However, unlike past studies, we found economically-disadvantaged students and students with disabilities were over-represented in Ohio’s virtual schools. The findings are explained through policy and legal lenses, and potential legal issues are discussed

Can Virtual Schools Thrive in the Real World?

Despite the relatively large number of students enrolled in Ohio’s virtual schools, it is unclear how virtual schools compare to their traditional school counterparts on measures of student achievement. To provide some insight, we compared the school performance from 2007-2011 at Ohio’s virtual and traditional schools. The results suggest that Ohio’s virtual schools have grown rapidly, but have also experienced much lower levels of school performance than traditional schools. In light of these findings, we discuss factors that may be contributing to the large number of low-performing virtual schools in Ohio. Considering the lack of sufficient evidence that Ohio’s virtual schools are effective, we conclude that the relentless pursuit to expand virtual schools is problematic

Structural basis of mitochondrial receptor binding and constriction by DRP1.

Mitochondrial inheritance, genome maintenance and metabolic adaptation depend on organelle fission by dynamin-related protein 1 (DRP1) and its mitochondrial receptors. DRP1 receptors include the paralogues mitochondrial dynamics proteins of 49 and 51 kDa (MID49 and MID51) and mitochondrial fission factor (MFF); however, the mechanisms by which these proteins recruit and regulate DRP1 are unknown. Here we present a cryo-electron microscopy structure of full-length human DRP1 co-assembled with MID49 and an analysis of structure- and disease-based mutations. We report that GTP induces a marked elongation and rotation of the GTPase domain, bundle-signalling element and connecting hinge loops of DRP1. In this conformation, a network of multivalent interactions promotes the polymerization of a linear DRP1 filament with MID49 or MID51. After co-assembly, GTP hydrolysis and exchange lead to MID receptor dissociation, filament shortening and curling of DRP1 oligomers into constricted and closed rings. Together, these views of full-length, receptor- and nucleotide-bound conformations reveal how DRP1 performs mechanical work through nucleotide-driven allostery

Pairing craft-making with Mandarin eBooks: An investigation into the use of craft for language learning by pre-schoolers

Bilingual ethnic Chinese parents are concerned about their preschoolers’ learning of their mother tongue. Many allow their children to learn Mandarin by accessing language applications on mobile devices. However the effectiveness of solely using mobile devices as a learning tool for preschoolers is debatable. This paper presents a field investigation on how adult-facilitated craft-making, generates greater interest the reading of Mandarin eBooks and retention of the stories. The data suggests pairing of activities may be useful to children from across language abilities. This also highlights a need for designers and educators to formulate a holistic design approach in the development of preschool mobile learning content

Volumetric facial contour changes of immediately placed implants with and without immediate provisionalization

BackgroundWhether immediate provisionalization can preserve facial tissue contour remains undetermined. The goal of this 12- month randomized controlled clinical trial was to compare three- dimensional (3D) ridge changes after immediate implant placement with and without immediate provisionalization.MethodsForty participants with an unrestorable maxillary anterior or premolar tooth were randomized to receive either a provisional crown (test) or standard healing abutment (control) after immediate implant placement. In each participant, three digital models taken before implant surgery, final crown delivery (4 months), and final follow- up (12 months) were registered to analyze linear deviation in 3D and volume changes of ridge contour at the implant site.ResultsThe mean value of mid- facial linear 3D spatial resorption ranged from 0.1 to 0.7 mm. Significant difference of linear changes of facial contour was noted over time and not between the groups. Facial volume changes at 12 months remained significantly higher in the control group than in the test group (17.4% versus 11.9%, P = 0.04).ConclusionsLinear changes of facial soft- tissue resorption at immediately placed implants were independent of immediate provisionalization. However, immediate provisionalization showed better volume preservation at the esthetic concern area (mid- facial margin and 2 to 6 mm above) at the final 12- month follow- up.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156220/2/jper10486_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156220/1/jper10486.pd