Cromakalim (BRL 34915) restores in vitro the membrane potential of depolarized human skeletal muscle fibres

The purpose of the present study was to analyze the effects of cromakalim (BRL 34915), a potent drug from a new class of drugs characterized as K+ channel openers, on the electrical activity of human skeletal muscle. Therefore, intracellular recordings were used to measure the effects of cromakalim on the membrane potential and input conductance of fibres from human skeletal muscle biopsies. Cromakalim in a concentration above 1 mol/l induced an increase in membrane K+ conductance. This effect resulted in a membrane hyperpolarization. The magnitude of this polarization depended on the difference between resting and K+ equilibrium potential. The effect had a rapid onset and was quickly reversible after washing. Fibres from two patients with hyperkalaemic periodic paralysis showed an excessive membrane depolarization during and also after exposure to an slightly elevated extracellular K+ concentration. In the latter situation, cromakalim repolarized the fibres to the normal resting potential. Tolbutamide (1 mmol/l) and Ba2+ (3 mmol/l) strongly antagonized the effect of cromakalim. The data show that cromakalim hyperpolarizes depolarized human skeletal muscle fibres maintained in vitro. The underlying mechanism is probably an activation of otherwise silent, ATP-regulated K+ channels. Such an effect may be of therapeutic benefit in a situation in which a membrane depolarization causes muscle paralysis

Single-qubit optical quantum fingerprinting

We analyze and demonstrate the feasibility and superiority of linear optical single-qubit fingerprinting over its classical counterpart. For one-qubit fingerprinting of two-bit messages, we prepare `tetrahedral' qubit states experimentally and show that they meet the requirements for quantum fingerprinting to exceed the classical capability. We prove that shared entanglement permits 100% reliable quantum fingerprinting, which will outperform classical fingerprinting even with arbitrary amounts of shared randomness.Comment: 4 pages, one figur

Quantum Nonlocal Boxes Exhibit Stronger Distillability

The hypothetical nonlocal box (\textsf{NLB}) proposed by Popescu and Rohrlich allows two spatially separated parties, Alice and Bob, to exhibit stronger than quantum correlations. If the generated correlations are weak, they can sometimes be distilled into a stronger correlation by repeated applications of the \textsf{NLB}. Motivated by the limited distillability of \textsf{NLB}s, we initiate here a study of the distillation of correlations for nonlocal boxes that output quantum states rather than classical bits (\textsf{qNLB}s). We propose a new protocol for distillation and show that it asymptotically distills a class of correlated quantum nonlocal boxes to the value $1/2 (3\sqrt{3}+1) \approx 3.098076$, whereas in contrast, the optimal non-adaptive parity protocol for classical nonlocal boxes asymptotically distills only to the value 3.0. We show that our protocol is an optimal non-adaptive protocol for 1, 2 and 3 \textsf{qNLB} copies by constructing a matching dual solution for the associated primal semidefinite program (SDP). We conclude that \textsf{qNLB}s are a stronger resource for nonlocality than \textsf{NLB}s. The main premise that develops from this conclusion is that the \textsf{NLB} model is not the strongest resource to investigate the fundamental principles that limit quantum nonlocality. As such, our work provides strong motivation to reconsider the status quo of the principles that are known to limit nonlocal correlations under the framework of \textsf{qNLB}s rather than \textsf{NLB}s.Comment: 25 pages, 7 figure

Student Recital: Peter A. Johnson, Horn; Kent Wehman, Piano; May 7, 1974

Centennial East Recital HallTuesday EveningMay, 7, 19748:15 p.m

Structured Near-Optimal Channel-Adapted Quantum Error Correction

We present a class of numerical algorithms which adapt a quantum error correction scheme to a channel model. Given an encoding and a channel model, it was previously shown that the quantum operation that maximizes the average entanglement fidelity may be calculated by a semidefinite program (SDP), which is a convex optimization. While optimal, this recovery operation is computationally difficult for long codes. Furthermore, the optimal recovery operation has no structure beyond the completely positive trace preserving (CPTP) constraint. We derive methods to generate structured channel-adapted error recovery operations. Specifically, each recovery operation begins with a projective error syndrome measurement. The algorithms to compute the structured recovery operations are more scalable than the SDP and yield recovery operations with an intuitive physical form. Using Lagrange duality, we derive performance bounds to certify near-optimality.Comment: 18 pages, 13 figures Update: typos corrected in Appendi

Mechanisierte Hormon-Analytik mittels simultaner Säulenchromatographie

Peer Reviewe

Typology of Teacher Leadership Programs

Education leaders are perennially seeking new ways to build the capacity of teachers to enhance learning experiences for all students. Teacher leadership, which we define as teachers’ support of the improvement of teaching and learning beyond their own classroom, has long been a source of interest and experimentation (Wenner & Campbell, 2017; York-Barr & Duke, 2004). Teacher leadership recognizes teachers’ instructional expertise as an asset for educational improvement, capitalizes upon teachers’ relationships with their colleagues to support change, and may provide career advancement opportunities to improve job satisfaction and the professionalization of teaching. For these and other reasons, states, districts, funders and teachers themselves have become increasingly interested in the promise of teacher leadership. In this study, we map the landscape of teacher leadership programs across the U.S. and identify commonalities and distinctions amongst the range of programs. Using a variety of search approaches to capture publicly-available information, we document 285 state, local, university, and foundation-sponsored programs that use a variety of techniques to support teachers as leaders. We then categorize the forms of support, attending to program models, objectives, sponsorship, and audience. We identify three major forms of support provided by teacher leadership programs: (1) preparation of teachers with knowledge and skills that can help them to lead; (2) positioning of teachers in leadership roles to capitalize upon their expertise; and (3) recognition of teachers as leaders through awards and other forms of appreciation or acknowledgement. While some programs focus only on one of these approaches, most employed a combination of these forms of support. Based on this, we define seven types of teacher leadership programs and provide an interactive depiction of this typology, with examples, to illustrate the variation within each of the seven types. While there are undoubtedly programs that escaped our view, as well as homegrown and informal initiatives that we could not document, this systematic search is the broadest scan of the teacher leadership program landscape conducted in the Unites States to date

Quantum Computing with Continuous-Variable Clusters

Continuous-variable cluster states offer a potentially promising method of implementing a quantum computer. This paper extends and further refines theoretical foundations and protocols for experimental implementation. We give a cluster-state implementation of the cubic phase gate through photon detection, which, together with homodyne detection, facilitates universal quantum computation. In addition, we characterize the offline squeezed resources required to generate an arbitrary graph state through passive linear optics. Most significantly, we prove that there are universal states for which the offline squeezing per mode does not increase with the size of the cluster. Simple representations of continuous-variable graph states are introduced to analyze graph state transformations under measurement and the existence of universal continuous-variable resource states.Comment: 17 pages, 5 figure