Robust two-qubit gates for donors in silicon controlled by hyperfine interactions

We present two strategies for performing two-qubit operations on the electron spins of an exchange-coupled pair of phosphorus donors in silicon, using the ability to set the donor nuclear spins in arbitrary states. The effective magnetic detuning of the two electron qubits is provided by the hyperfine interaction when the $^{31}$P nuclei are prepared in opposite spin states. This can be exploited to switch on and off SWAP operations with modest tuning of the electron exchange interaction. Furthermore, the hyperfine detuning enables high-fidelity conditional rotation gates based on selective resonant excitation. The latter requires no dynamic tuning of the exchange interaction at all, and offers a very attractive scheme to implement two-qubit logic gates under realistic experimental conditions.Comment: 8 pages, 3 figure

Are SREB States Making Progress? Tapping, Preparing and Licensing School Leaders Who Can Influence Student Achievement

Looks at the progress SREB states are making in developing systems to identify, prepare, and assess future school leaders

Are anonymity-seekers just like everybody else? An analysis of contributions to Wikipedia from Tor

User-generated content sites routinely block contributions from users of privacy-enhancing proxies like Tor because of a perception that proxies are a source of vandalism, spam, and abuse. Although these blocks might be effective, collateral damage in the form of unrealized valuable contributions from anonymity seekers is invisible. One of the largest and most important user-generated content sites, Wikipedia, has attempted to block contributions from Tor users since as early as 2005. We demonstrate that these blocks have been imperfect and that thousands of attempts to edit on Wikipedia through Tor have been successful. We draw upon several data sources and analytical techniques to measure and describe the history of Tor editing on Wikipedia over time and to compare contributions from Tor users to those from other groups of Wikipedia users. Our analysis suggests that although Tor users who slip through Wikipedia's ban contribute content that is more likely to be reverted and to revert others, their contributions are otherwise similar in quality to those from other unregistered participants and to the initial contributions of registered users.Comment: To appear in the IEEE Symposium on Security & Privacy, May 202

Pax1 and Pax9 activate Bapx1 to induce chondrogenic differentiation in the sclerotome.

We have previously shown that the paired-box transcription factors Pax1 and Pax9 synergistically act in the proper formation of the vertebral column. Nevertheless, downstream events of the Pax1/Pax9 action and their target genes remain to be elucidated. We show, by analyzing Pax1;Pax9 double mutant mice, that expression of Bapx1 in the sclerotome requires the presence of Pax1 and Pax9, in a gene dose-dependent manner. By using a retroviral system to overexpress Pax1 in chick presomitic mesoderm explants, we show that Pax1 can substitute for Shh in inducing Bapx1 expression and in initiating chondrogenic differentiation. Furthermore, we demonstrate that Pax1 and Pax9 can transactivate regulatory sequences in the Bapx1 promoter and that they physically interact with the Bapx1 promoter region. These results strongly suggest that Bapx1 is a direct target of Pax1 and Pax9. Together, we conclude that Pax1 and Pax9 are required and sufficient for the chondrogenic differentiation of sclerotomal cells

An elastoplastic framework for granular materials becoming cohesive through mechanical densification. Part II - the formulation of elastoplastic coupling at large strain

The two key phenomena occurring in the process of ceramic powder compaction are the progressive gain in cohesion and the increase of elastic stiffness, both related to the development of plastic deformation. The latter effect is an example of `elastoplastic coupling', in which the plastic flow affects the elastic properties of the material, and has been so far considered only within the framework of small strain assumption (mainly to describe elastic degradation in rock-like materials), so that it remains completely unexplored for large strain. Therefore, a new finite strain generalization of elastoplastic coupling theory is given to describe the mechanical behaviour of materials evolving from a granular to a dense state. The correct account of elastoplastic coupling and of the specific characteristics of materials evolving from a loose to a dense state (for instance, nonlinear --or linear-- dependence of the elastic part of the deformation on the forming pressure in the granular --or dense-- state) makes the use of existing large strain formulations awkward, if even possible. Therfore, first, we have resorted to a very general setting allowing general transformations between work-conjugate stress and strain measures; second, we have introduced the multiplicative decomposition of the deformation gradient and, third, employing isotropy and hyperelasticity of elastic response, we have obtained a relation between the Biot stress and its `total' and `plastic' work-conjugate strain measure. This is a key result, since it allows an immediate achievement of the rate elastoplastic constitutive equations. Knowing the general form of these equations, all the specific laws governing the behaviour of ceramic powders are finally introduced as generalizations of the small strain counterparts given in Part I of this paper.Comment: 18 pages, 1 figur

The Problem with Teaching Science, Technology, Engineering, and Math as Inquiry Versus by Inquiry

4-H professionals implementing problem-based learning and other minimally guided instruction techniques in science, technology, engineering, and math education often do so with learners working in small groups, a strategy that allows learners to construct knowledge through social interactions. However, educators who implement these techniques without an understanding of human cognitive architecture risk confusing the teaching of a discipline as inquiry with the teaching of the discipline by inquiry. The assumption that knowledge is learned best through experience does not account for the difference between experts who are practicing a profession and students who are learning to practice a profession

\u3ci\u3eRemote: Office Not Required\u3c/i\u3e—A Book Review

Remote: Office Not Required by Jason Fried and David Heinemeier Hansson offers a novel perspective into the modern workplace practice of remote work. This book provides an outline for becoming an expert in remote work, both as a leader and as a practitioner. Fried and Hansson describe tools and methods that help practitioners find success when implementing remote work and explain how to avoid common obstacles. Although drawbacks and challenges exist, the authors maintain that remote work is likely more compatible with organizations than leaders might think, maintaining that the advantages outweigh the disadvantages

Coming to grips with student mobility and policy implications: a case study from regional Queensland

In 2008, in what could be considered a significant shift in Australian education policy, Rudd and Gillard stated that,"'business as usual' in Australian schools will not, by itself, substantially lift educational outcomes, particularly in low SES communities" (2008, p.26). They highlighted the need for schools to not only "commit to excellence in teaching and learning within the classroom, but . . . be prepared to address the range of external factors that impact on students' ability to engage in learning"(ibid). This paper summarises some of the issues exposed through a collaborative research project with schools related to one set of external factors in lower socio-economic communities - student mobility or movement of students between schools. Taking a policy research perspective, informed by Dale(1989), Rist (2005) and Ball (1994), the paper examines the relationship between 'wider policies of the state' in particular marketisation and considers how mobility plays out in school sites, specifically school sites marked by poverty. The paper firstly presents an overview of the issues related to the measurement of mobility outlining the various ways stability within school populations has been measured. The paper argues for a measurement tool that reflects both the transactional pressure student mobility creates for schools and teachers but also the complexity conferred by poverty, suggesting that current metrics effectively mask issues of mobility within such communities. The paper then presents research findings on the work of schools and teachers in relation to mobile students. Through a detailed analysis of this work, actions are located as serving the interests of the state - technical transactions related to the Education (General Provisions) Act 2006, practical requirements related to inducting students to a new school and, most importantly, critical actions related to student learning and support needs. The use of this framework to examine the work of teachers exposes the 'complex interplay of interests' (Ball, 1997) that require visibility within any policy reform. Using Rist's (2005) notion of research as having an 'enlightenment function' the paper argues that sustained collaborative research with schools can expose the complexities of such phenomena as student mobility. In the context of renewed commitment to 'needs based funding', the paper concludes with suggested directions to support individual case management of mobile students within a social justice framework and a call for the reconsideration of the role of the state in order to reduce mobility in low SES communities

Keeping Social Studies Alive in the Elementary Classroom: Countering the Effects of NCLB in Southwestern Illinois Schools

This research project focuses on collaborative partnerships between university faculty, graduate students, and local cooperating teachers. Pre-service teachers surveyed cooperating teachers (N=30) regarding their opinions and practices in social studies education. The data led to positive changes in a university methods course and increased pedagogical skills for teacher candidates. This venture is a model of effective collaboration between university faculty, graduate students, pre-service teachers, and cooperating teachers who have worked together to gain a deeper understanding of the purpose and challenges faced by social studies educators. The overall goal of the project is to promote social studies education for all elementary students, particularly those in southwestern Illinois

Keeping Social Studies Alive in the Elementary Classroom: Countering the Effects of NCLB in Southwestern Illinois Schools

This research project focuses on collaborative partnerships between university faculty, graduate students, and local cooperating teachers. Pre-service teachers surveyed cooperating teachers (N=30) regarding their opinions and practices in social studies education. The data led to positive changes in a university methods course and increased pedagogical skills for teacher candidates. This venture is a model of effective collaboration between university faculty, graduate students, pre-service teachers, and cooperating teachers who have worked together to gain a deeper understanding of the purpose and challenges faced by social studies educators. The overall goal of the project is to promote social studies education for all elementary students, particularly those in southwestern Illinois