Controlling quantum systems by embedded dynamical decoupling schemes

A dynamical decoupling method is presented which is based on embedding a deterministic decoupling scheme into a stochastic one. This way it is possible to combine the advantages of both methods and to increase the suppression of undesired perturbations of quantum systems significantly even for long interaction times. As a first application the stabilization of a quantum memory is discussed which is perturbed by one-and two-qubit interactions

Network Synthesis

Contains research objectives and reports on three research objectives

Single-experiment-detectable multipartite entanglement witness for ensemble quantum computing

In this paper we provide an operational method to detect multipartite entanglement in ensemble-based quantum computing. This method is based on the concept of entanglement witness. We decompose the entanglement witness for each class of multipartite entanglement into nonlocal operations in addition to local measurements. Individual single qubit measurements are performed simultaneously, hence complete detection of entanglement is performed in a single run experiment. This approach is particularly important for experiments where it is operationally difficult to prepare several copies of an unknown quantum state and in this sense the introduced scheme in this work is superior to the generally used entanglement witnesses that require a number of experiments and preparation of copies of quantum state.Comment: 9 pages, 5 figures, minor changes have been mad

A review of the Energy Productivity Center's Least-Cost Energy Strategy study

The Mellon Institute's Energy Productivity Center (EPC) has recently completed a study asking the question, "How would the nation have provided energy services in 1978 if its capital stock had een reconfigured to be optimal for actual 1978 energy prices?" Interest in this question is motivated by the unanticipated increases in oil prices since 1973. If policy makers are to learn from history it is important to know what would have happened if the increases in energy prices had been foreseen and if the nation had taken full advantage of that knowledge to minimize costs.EPC concludes that if the 1978 capital stock had been transformed in conformance with a least-cost principal for providing energy services, then, given actual 1978 energy prices and energy service demands, per capita energy service costs would have been reduced by 17%. Market shares of the various energy types would also have been affected substantially. For example, while the gas share of total energy service demand would have increased slightly from actual 1978 levels, the share of purchased electricity would have fallen from 30% to 17% of total energy service demand, and improvements in energy efficiency would have increased from 10% to 32%.EPC's findings have received considerable attention, both from the press and from policy makers. EPC interprets its results as indicating "... the direction in which we coul move to begin realizing some of the benefits of a least-cost strategy." The purpose of this report is to assess and evaluate the EPC methodology, data base, and results. Here we briefly summarize our principal findings

Developments In Stem Educators’ Preparedness For English Language Learners In The United States

In the United States, the population of students classified as English Language Learners (ELLs) in K-12 education has increased in recent decades. As a result, teachers outside of specialized linguistic courses have needed to adapt their instruction to better meet the needs of these students. This exploratory study investigates potential indicators of Science, Technology, Engineering, and Mathematics (STEM) teachers’ preparedness to work with ELLs, in comparison with the rates of ELLs in STEM courses.   Data for this study were obtained from the national restricted-access datasets of the 2007-2008 and 2011-2012 School and Staffing Survey (SASS) Teacher Questionnaire (TQ). STEM teachers’ participation in ELL-focused professional development activities, credentialing related to ELLs, and ELL populations in STEM teachers’ courses were analyzed to quantify changes in these measures over time and among the STEM disciplines. Regional analysis of STEM teacher populations and ELL populations in STEM classes was also conducted to examine how these factors differed across the United States.   Analyses of these data indicated increases in the percentage of STEM teachers who have ELLs in their service loads and in the average number of ELLs in teacher service loads; these trends were present in all U.S. regions and in all STEM disciplines. However, the total number of STEM teachers who participated in ELL-focused professional development activities increased only slightly over the four-year span. To effectively teach the growing ELL student population, STEM teachers must develop the skills and approaches necessary to educate and engage these students

Intracellular localization of the proteasome in response to stress conditions

The ubiquitin-proteasome-system (UPS) fulfills an essential role in regulating protein homeostasis by spatially and temporally controlling proteolysis in an ATP- and ubiquitin-dependent manner. However, the localization of proteasomes is highly variable under diverse cellular conditions. In yeast, newly synthesized proteasomes are primarily localized to the nucleus during cell proliferation. Yeast proteasomes are transported into the nucleus through the nuclear pore either as immature subcomplexes or as mature enzymes via adaptor proteins Sts1 and Blm10, while in mammalian cells, post-mitotic uptake of proteasomes into the nucleus is mediated by AKIRIN2, an adaptor protein essentially required for nuclear protein degradation. Stressful growth conditions and the reversible halt of proliferation, i.e. quiescence, are associated with a decline in ATP and the re-organization of proteasome localization. Cellular stress leads to proteasome accumulation in membraneless granules either in the nucleus or in the cytoplasm. In quiescence, yeast proteasomes are sequestered in a ubiquitin-dependent manner into motile and reversible proteasome storage granules (PSGs) in the cytoplasm. In cancer cells upon amino acid deprivation, heat shock, osmotic stress, oxidative stress, or the inhibition of either proteasome activity or nuclear export, reversible proteasome foci containing poly-ubiquitinated substrates are formed by liquid-liquid phase separation in the nucleus. In this review, we summarize recent literature revealing new links between nuclear transport, ubiquitin signaling and the intracellular organization of proteasomes during cellular stress conditions

Progressive retinal degeneration and glial activation in the Cln6nclf mouse model of neuronal ceroid lipofuscinosis : a beneficial effect of DHA and Curcumin supplementation

Neuronal ceroid lipofuscinosis (NCL) is a group of neurodegenerative lysosomal storage disorders characterized by vision loss, mental and motor deficits, and spontaneous seizures. Neuropathological analyses of autopsy material from NCL patients and animal models revealed brain atrophy closely associated with glial activity. Earlier reports also noticed loss of retinal cells and reactive gliosis in some forms of NCL. To study this phenomenon in detail, we analyzed the ocular phenotype of CLN6nclf mice, an established mouse model for variant-late infantile NCL. Retinal morphometry, immunohistochemistry, optokinetic tracking, electroretinography, and mRNA expression were used to characterize retinal morphology and function as well as the responses of Müller cells and microglia. Our histological data showed a severe and progressive degeneration in the CLN6nclf retina co-inciding with reactive Müller glia. Furthermore, a prominent phenotypic transformation of ramified microglia to phagocytic, bloated, and mislocalized microglial cells was identified in CLN6nclf retinas. These events overlapped with a rapid loss of visual perception and retinal function. Based on the strong microglia reactivity we hypothesized that dietary supplementation with immuno-regulatory compounds, curcumin and docosahexaenoic acid (DHA), could ameliorate microgliosis and reduce retinal degeneration. Our analyses showed that treatment of three-week-old CLN6nclf mice with either 5% DHA or 0.6% curcumin for 30 weeks resulted in a reduced number of amoeboid reactive microglia and partially improved retinal function. DHA-treatment also improved the morphology of CLN6nclf retinas with a preserved thickness of the photoreceptor layer in most regions of the retina. Our results suggest that microglial reactivity closely accompanies disease progression in the CLN6nclf retina and both processes can be attenuated with dietary supplemented immuno-modulating compounds