High-temperature capacitive strain measurement system

Capacitive strain gage and signal conditioning system measures stress-induced strain and cancels thermal expansion strain at temperatures to 1,500 F (815 C). Gage does not significantly restrain or reinforce specimen

Path-integral Monte Carlo simulations for interacting few-electron quantum dots with spin-orbit coupling

We develop path-integral Monte Carlo simulations for a parabolic two-dimensional (2D) quantum dot containing $N$ interacting electrons in the presence of Dresselhaus and/or Rashba spin-orbit couplings. Our method solves in a natural way the spin contamination problem and allows for numerically exact finite-temperature results at weak spin-orbit coupling. For $N<10$ electrons, we present data for the addition energy, the particle density, and the total spin $S$ in the Wigner molecule regime of strong Coulomb interactions. We identify magic numbers at N=3 and N=7 via a peak in the addition energy. These magic numbers differ both from weak-interaction and classical predictions, and are stable with respect to (weak) spin-orbit couplings.Comment: 9 pages, 6 figures, 1 table, few minor changes, published versio

The Role of Introductory Geoscience Courses in Preparing Teachers—And All Students—For the Future: Are We Making the Grade?

Introductory geoscience courses enroll hundreds of thousands of students a year, most of whom do not major in the geosciences. For many, including future K–12 teachers, an introductory course is the only place they will encounter Earth science at the college level. New standards for K–12 science education have profound implications for teacher preparation, particularly in Earth science. The new standards call for taking a systems approach, highlighting how humans interact with Earth, making use of science and engineering practices, and engaging students in discourse. Analysis of responses to the National Geoscience Faculty Survey (n = 813 in 2004; n = 994 in 2009; n = 972 in 2012; and n = 1074 in 2016) and data from 152 syllabi suggest that a systems approach is not widespread and human interactions with Earth are not emphasized, and that most instructors engage students in mostly low cognitive-level practices. While the use of discourse practices has increased over time, these and other active learning components are not yet widely included in students’ grades. These results suggest that courses are not currently well-aligned with teacher needs. However, instructors have access to many research-based instructional resources to support them in making changes that will help all students—including future teachers

The Trade Effects of Endogenous Preferential Trade Agreements

Recent work by Anderson and van Wincoop (2003) establishes an empirical modelling strategy which takes full account of the structural, non-(log-)linear impact of trade barriers on trade in new trade theory models. Structural new trade theory models have never been used to evaluate and quantify the role of endogenous preferential trade agreement (PTA) membership for trade in a way which is consistent with general equilibrium. Apart from this gap, the present paper aims at delivering an empirical model which takes into account both that preferential trade agreement membership is endogenous and that the world matrix of bilateral trade flows contains numerous zero entries. These features are treated in an encompassing way by means of (possibly two-part) Poisson pseudo-maximum likelihood estimation with endogenous binary indicator variables in the empirical model.gravity model, endogenous preferential trade agreement membership, Poisson pseudo-maximum likelihood estimation with endogenous binary indicator variables

The Trade Effects of Endogenous Preferential Trade Agreements

Recent work by Anderson and van Wincoop (2003) establishes an empirical modeling strategy which takes full account of the structural, non-(log-)linear impact of trade barriers on trade in new trade theory models. Structural new trade theory models have never been used to evaluate and quantify the role of endogenous preferential trade agreement (PTA) membership for trade in a way which is consistent with general equilibrium. Apart from this gap, the present paper aims at delivering an empirical model which takes into account both that preferential trade agreement membership is endogenous and that the world matrix of bilateral trade flows contains numerous zero entries. These features are treated in an encompassing way by means of (possibly two-part) Poisson pseudo-maximum likelihood estimation with endogenous binary indicator variables in the empirical model.Gravity model, Endogenous preferential trade agreement membership, Poisson pseudo-maximum likelihood estimation with endogenous binary indicator variables

Hearing voices, dissociation and the self: a functional-analytic perspective

Item does not contain fulltextIn the current paper, we review existing models of the aetiology of voice hearing. We summarise the argument and evidence that voice hearing is primarily a dissociative process, involving critical aspects of self. We propose a complementary perspective on these phenomena that is based on a modern behavioural account of complex behaviour, known as Relational Frame Theory (RFT). This type of approach to voice hearing concerns itself with: the functions served for the individual by this voice hearing; the necessary history, such as trauma, that establishes these functions; and the relevant dissociative processes involving self and others. In short, we propose a trauma-dissociation developmental trajectory in which trauma impacts negatively on the development of self, through the process of dissociation. Using the RFT concept of relations of perspective-taking, our dissociation model purports that trauma gives rise to more co-ordination than distinction relations between self and others, thus weaking an individual's sense of a distinct self. Voice hearing experiences, therefore, reflect an individual's perceptions of self and others, and may indicate impairments in the natural psychological boundaries between these critical related concepts. One clinical implication suggested by this model is that therapeutic 'intervention' should understand the behaviours associated with a sense of self that is fragile and threatened by others. Relations with self and others should be a key focus of therapy, as well as interventions designed to enhance a coherent distinct sense of self.20 p

Coulomb Charging at Large Conduction

We discuss the suppression of Coulomb charging effects on a small metallic island coupled to an electrode by a tunnel junction. At high temperatures the quantum corrections to the classical charging energy $E_c=e^2/2C$, where $C$ is the island capacitance, are evaluated. At low temperatures the large quantum fluctuations of the island charge cause a strong reduction of the effective $E_c$ which is determined explicitly in the limit of a large tunneling conductance.Comment: 4 page

Roadmap to Majorana surface codes

Surface codes offer a very promising avenue towards fault-tolerant quantum computation. We argue that two-dimensional interacting networks of Majorana bound states in topological superconductor/semiconductor heterostructures hold several distinct advantages in that direction, both concerning the hardware realization and the actual operation of the code. We here discuss how topologically protected logical qubits in this Majorana surface code architecture can be defined, initialized, manipulated, and read out. All physical ingredients needed to implement these operations are routinely used in topologically trivial quantum devices. In particular, we show that by means of quantum interference terms in linear conductance measurements, composite single-electron pumping protocols, and gate-tunable tunnel barriers, the full set of quantum gates required for universal quantum computation can be implemented.Comment: 23 pages, 8 figure