Orbits of quantum states and geometry of Bloch vectors for NN-level systems

Physical constraints such as positivity endow the set of quantum states with a rich geometry if the system dimension is greater than two. To shed some light on the complicated structure of the set of quantum states, we consider a stratification with strata given by unitary orbit manifolds, which can be identified with flag manifolds. The results are applied to study the geometry of the coherence vector for n-level quantum systems. It is shown that the unitary orbits can be naturally identified with spheres in R^{n^2-1} only for n=2. In higher dimensions the coherence vector only defines a non-surjective embedding into a closed ball. A detailed analysis of the three-level case is presented. Finally, a refined stratification in terms of symplectic orbits is considered.Comment: 15 pages LaTeX, 3 figures, reformatted, slightly modified version, corrected eq.(3), to appear in J. Physics

Improving Depression Care for Older Home Health Patients

Rates of depression in older home healthcare (HH) patients are highly prevalent. Although depression in this population is associated with increased rates of re-hospitalization, falls, and suicides, it is frequently under diagnosed and under treated. This Capstone Report examined this problem through three interrelated manuscripts. The first manuscript explored the problem through a review of the literature. This review determined that while there are many barriers to adequate depression care, programs that train clinicians to screen for depression and connect patients to depression care encourage adequate evaluation and treatment and can result in clinically significant changes in depression scores. This review prompted the development and implementation of a depressive disorder protocol implemented in a HH agency. The second manuscript describes the results of a process evaluation, which examined HH clinician fidelity of the protocol. Trained HH clinicians did administer the PHQ-9 according to protocol and seemed more comfortable recording higher depression scores. However, trained clinicians did not refer to a mental health nurse more frequently. Important ways in which the Doctor of Nursing Practice (DNP) prepared clinician can improve care in this area are identified. The report concludes with a policy position statement and recommendations for policy change to improve depression care for older HH patients at various stakeholder levels. Programs that integrate depression care with chronic illness management make good use of HH agency resources and can be operationally and financially feasible

Implementation of Fault-tolerant Quantum Logic Gates via Optimal Control

The implementation of fault-tolerant quantum gates on encoded logic qubits is considered. It is shown that transversal implementation of logic gates based on simple geometric control ideas is problematic for realistic physical systems suffering from imperfections such as qubit inhomogeneity or uncontrollable interactions between qubits. However, this problem can be overcome by formulating the task as an optimal control problem and designing efficient algorithms to solve it. In particular, we can find solutions that implement all of the elementary logic gates in a fixed amount of time with limited control resources for the five-qubit stabilizer code. Most importantly, logic gates that are extremely difficult to implement using conventional techniques even for ideal systems, such as the T-gate for the five-qubit stabilizer code, do not appear to pose a problem for optimal control.Comment: 18 pages, ioptex, many figure

Multi-conjugated adaptive optics imaging of distant galaxies -- A comparison of Gemini/GSAOI and VLT/HAWK-I data

Multi-conjugated adaptive optics (MCAO) yield nearly diffraction-limited images at 2$\mu$m wavelengths. Currently, GeMS/GSAOI at Gemini South is the only MCAO facility instrument at an 8m telescope. Using real data and for the first time, we investigate the gain in depth and S/N when MCAO is employed for $K_{\rm s}$-band observations of distant galaxies. Our analysis is based on the Frontier Fields cluster MACS J0416.1-2403, observed with GeMS/GSAOI (near diffraction-limited) and compared against VLT/HAWK-I (natural seeing) data. Using galaxy number counts, we show that the substantially increased thermal background and lower optical throughput of the MCAO unit are fully compensated for by the wavefront correction, because the galaxy images can be measured in smaller apertures with less sky noise. We also performed a direct comparison of the signal-to-noise ratios (S/N) of sources detected in both data sets. For objects with intrinsic angular sizes corresponding to half the HAWK-I image seeing, the gain in S/N is 40 per cent. Even smaller objects experience a boost in S/N by a up to a factor of 2.5 despite our suboptimal natural guide star configuration. The depth of the near diffraction limited images is more difficult to quantify than that of seeing limited images, due to a strong dependence on the intrinsic source profiles. Our results emphasize the importance of cooled MCAO systems for $K_{\rm s}$-band observations with future, extremely large telescopes.Comment: 7 pages, 7 figures. Accepted for publication in MNRA

Dominant gain-of-function mutations in Hsp104p reveal crucial roles for the middle region

Heat-shock protein 104 (Hsp104p) is a protein-remodeling factor that promotes survival after extreme stress by disassembling aggregated proteins and can either promote or prevent the propagation of prions (protein-based genetic elements). Hsp104p can be greatly overexpressed without slowing growth, suggesting tight control of its powerful protein-remodeling activities. We isolated point mutations in Hsp104p that interfere with this control and block cell growth. Each mutant contained alterations in the middle region (MR). Each of the three MR point mutations analyzed in detail had distinct phenotypes. In combination with nucleotide binding site mutations, Hsp104p(T499I) altered bud morphology and caused septin mislocalization, colocalizing with the misplaced septins. Point mutations in the septin Cdc12p suppressed this phenotype, suggesting that it is due to direct Hsp104p–septin interactions. Hsp104p(A503V) did not perturb morphology but stopped cell growth. Remarkably, when expressed transiently, the mutant protein promoted survival after extreme stress as effectively as did wild-type Hsp104p. Hsp104p(A509D) had no deleterious effects on growth or morphology but had a greatly reduced ability to promote thermotolerance. That mutations in an 11-amino acid stretch of the MR have such profound and diverse effects suggests the MR plays a central role in regulating Hsp104p function

Identifying Evidence-Based Educational Practices: Which Research Designs Provide Findings that Can Influence Social Change?

We conducted this conceptual study to determine if the Institute of Education Sciences/National Science Foundation pipeline of evidence guidelines could be applied as a protocol that researchers could follow in establishing evidence of effective instructional practices. To do this, we compared these guidelines, new drug development process, and our own research on major methodological designs and found that they show remarkable consistency in the process by which types of studies intended to answer different research questions build a body of evidence for practice, whether that practice is in the instructional environment or health care environment. However, none of the protocols offers a constellation of studies at each stage that would be essential for movement to the next stage or the indicators of quality for each type of study. The goal of this effort is to develop consensus in the educational research community about a pipeline of evidence protocol that provides educators with confidence that the instructional practices they employ have a high likelihood of success and will enable a positive impact on the student’s learning and, in the broader context, the student’s ability to contribute to society

Relevance of the IES/NSF Protocol to Identification of Evidence-Based Practices

The Institute of Education Sciences (IES) and the National Science Foundation (NSF) issued common guidelines that provide a protocol by which the use of particular methodological designs in a line of research inquiry provides evidence for each successive step in the process of bringing any given instructional intervention into practice. Our purpose was to determine if research on two widely used literacy instruction approaches has been conducted at each methodological stage in the IES/NSF protocol and is relevant to identifying the approach as an evidence-based practice. We applied the IES/NSF pipeline-of-evidence guidelines to assess whether practices touted as having a research base for effectiveness have emerged from an accumulation of empirical evidence and identification of conceptual or theoretical frameworks. In mapping the six steps of the IES/NSF protocol onto the shared book reading and reciprocal teaching studies that had met What Works Clearinghouse evidence standards, we found that only reciprocal teaching involved research at each stage in the protocol and only reciprocal teaching was identified as an evidence-based instructional approach by the What Works Clearinghouse. Our results indicate that the IES/NSF pipeline-of-evidence protocol offers a productive approach to identifying evidence-based practices. The different trajectories of research on reciprocal teaching and shared book reading indicates that research at each stage in the protocol is important to the development of an instructional approach that ultimately demonstrates effectiveness in improving student learning outcomes

IES/NSF Pipeline-of-Evidence Protocol as Explanation for Successes and Failures of Gates Foundation Funded Initiatives

This study was designed to investigate the applicability of the IES/NSF pipeline-of-evidence protocol in ascertaining why two notable educational initiatives spearheaded and financially supported by the Bill and Melinda Gates Foundation achieved or not the goal of improved academic outcomes for K-12 public school students. Our interest was not whether there is a sufficient body of high quality research evidence to support the two initiatives but whether the research considered by the Gates Foundation established the likelihood that the initiatives would be successful and worth the decision to dedicate substantial funding, time, and effort required for each versus the many competing programs seeking sponsorship. We found that in the case of Intensive Partnerships for Effective Teaching, foundational, efficacy, and effectiveness research were absent and the Gates foundation discontinued grant support because the initiative had not achieved the goal of improved high school graduation and college attendance among low-income minority students. In the case of Early College High School, we found empirical evidence was manifest at all but the effectiveness stage of the pipeline and the initiative continued to receive funding. Our findings support the importance of widening the net of methodologies that constitute a framework for elements needed to make predictions of effectiveness for any given intervention before investing in scale-up initiatives and the need for private foundations to be transparent in their decision-making process to enable others to scrutinize the research that informs the design of initiatives

ZZE-Configuration of chromophore ß-153 in C-phycocyanin from Mastigocladus laminosus

The photochemistry of C-phycocyanin has been studied after denaturation in the dark. It shows an irreversible reaction which has characteristics of a Ζ,Ζ,Ε- to Z,Z,Z-isomerization of dihydrobilins. Its amplitude depends on the reaction conditions, with a maximum corresponding to 15% conversion of one of the three PC chromophores. This chromophore is suggested to be ß-153, for which recent X-ray data T. Schirmer, W. Bode, and R. Huber, J. Mol. Biol., submitted, show ring D being highly twisted out of the plane of the other rings. During unfolding, there is thus a probability of falling into the photochemically labile Z,Z,^-configuration