Cyclic quantum evolution and Aharonov-Anandan geometric phases in SU(2) spin-coherent states

This is the published version, also available here: http://dx.doi.org/10.1103/PhysRevA.41.42.We show that cyclic quantum evolution can be realized and the Aharonov-Anandan (AA) geometric phase can be determined for any spin-j system driven by periodic fields. Two methods are extended for the study of this problem: the generalized spin-coherent-state technique and the Floquet quasienergy approach. Using the former approach, we have developed a generalized Bloch-sphere model and presented a SU(2) Lie-group formulation of the AA geometric phase in the spin-coherent state. We show that the AA phase is equal to j times the solid angle enclosed by the trajectory traced out by the tip of a generalized Bloch vector. General analytic formulas are obtained for the Bloch vector trajectory and the AA geometric phase in terms of external physical parameters. In addition to these findings, we have also approached the same problem from an alternative but complementary point of view without recourse to the concept of coherent-state terminology. Here we first determine the Floquet quasienergy eigenvalues and eigenvectors for the spin-j system driven by periodic fields. This in turn allows the construction of the time-evolution propagator, the total wave function, and the AA geometric phase in a more general fashion

Nonperturbative treatments of level shifts of excited states and high-order harmonic generation in strong fields

This is the published version, also available here: http://dx.doi.org/10.1364/JOSAB.7.000425.In this paper we accomplish three goals. First, we present new nonperturbative results of complex quasi-energies (shifts and widths) for several low-lying excited states of atomic H in strong fields, using the L2 non-Hermitian Floquet matrix technique. Second, we present a new nonperturbative L2 technique for the treatment of ac Stark shifts of arbitrary excited states. We found that all the Rydberg states in weak fields are upshifted and closely follow the quadratic field dependence described by the ponderomotive potential e2F2/4mω2. Large deviation from the ponderomotive shift and intricate level-shift behaviors, however, occur in strong fields. Finally, we present a classical nonperturbative treatment of the electronic motion in intense laser fields. We show that the spectral analysis of classical trajectories can provide detailed insights regarding the mechanisms responsible for the multiple-harmonic generation recently observed in high-intensity experiments

Depot Park: An Ecological Showcase

Depot Park is the central gathering space for the City of the Village of Clarkston. Clarkston is a small village located 45 minutes north of Detroit in Southeastern Michigan. The village is approximately one-half mile square, and its small size reflects the community’s desire to uphold the historic village boundaries. Clarkston has a popular influence on surrounding communities, and many neighboring citizens in Independence Township consider themselves from the village, though they live beyond Clarkston’s official boundaries. Depot Park is located in the heart of Clarkston’s historic downtown. The park serves many civic functions throughout the year, including Art in the Park, farmers markets, summer concerts, and car club events. The park has a prime location to educate and inspire the public, and its current popularity engages visitors from Clarkston and surrounding communities. The Clarkston Watershed Group (CWG) is a group of committed citizens that are focused on improving Depot Park and protecting the natural resources of the greater Clarkston area. With its central location and frequent use, Depot Park can become a living tool to illustrate principles of ecological and sustainable design. The park is currently operating without a master plan, which complicates routine decisions such as placement of memorials. The University of Michigan team is providing the Clarkston Watershed Group with a cohesive master plan that will ensure the future success of Depot Park as an inspiring and effective civic space. This University of Michigan Masters Practicum Team specializes in providing designs that are both ecologically sensitive and aesthetically engaging. Our educational background in ecological design complements the environmental enthusiasm of the Clarkston Watershed Group. With the implementation of our master plan and supporting documents, the CWG can continue to foster education and environmental change in and around Depot Park.Master of Landscape ArchitectureNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/58215/4/Watershed Handbook.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/58215/3/Final Species List Depot Park.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/58215/2/Final Display Boards Depot Park.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/58215/1/Executive Summary_Depot Park_4-14-2008.pd

Focal Plane Metrology for the LSST Camera

Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane

Telomerecat: A ploidy-agnostic method for estimating telomere length from whole genome sequencing data.

Telomere length is a risk factor in disease and the dynamics of telomere length are crucial to our understanding of cell replication and vitality. The proliferation of whole genome sequencing represents an unprecedented opportunity to glean new insights into telomere biology on a previously unimaginable scale. To this end, a number of approaches for estimating telomere length from whole-genome sequencing data have been proposed. Here we present Telomerecat, a novel approach to the estimation of telomere length. Previous methods have been dependent on the number of telomeres present in a cell being known, which may be problematic when analysing aneuploid cancer data and non-human samples. Telomerecat is designed to be agnostic to the number of telomeres present, making it suited for the purpose of estimating telomere length in cancer studies. Telomerecat also accounts for interstitial telomeric reads and presents a novel approach to dealing with sequencing errors. We show that Telomerecat performs well at telomere length estimation when compared to leading experimental and computational methods. Furthermore, we show that it detects expected patterns in longitudinal data, repeated measurements, and cross-species comparisons. We also apply the method to a cancer cell data, uncovering an interesting relationship with the underlying telomerase genotype

Publisher Correction: Telomerecat: A ploidy-agnostic method for estimating telomere length from whole genome sequencing data.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper

Fabrication and characterization of porous NiTi Shape Memory Alloy by elevated pressure sintering

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 95-105).Issued also on microfiche from Lange Micrographics.Shape Memory Alloys (SMAs) have emerged as a class of materials with unique thermal and mechanical properties that have found numerous applications in various engineering fields. Even beyond the shape memory characteristics inherent in dense SMAs, porous SMAs with a relatively low density would expand the applicability of SMAs. In addition to the large recoverable strains observed by SMAs, porous SMAs offer the possibility of undergoing greater overall strains as well as much higher specific energy absorption under dynamic loading conditions due to the possibility of wave scattering. Porous SMAs also offer the possibility of impedance matching by grading the porosity at connecting joints with other structural materials. In biomedicine, porous SMAs have been successfully used in such applications as bone implants and dental repairs. Despite their high potential for practical use, porous SMAs have not been sufficiently studied in the U.S., and techniques for their commercial production have not been adequately developed. Currently, three methods are commonly used for producing porous NiTi SMAs from elemental powders. These methods include conventional sintering, Self-propagating High-temperature Synthesis (SHS), and sintering at elevated pressure via a Hot Isostatic Press (HIP). Conventional sintering requires long heating times and samples are limited in shape and pore size. SHS, which is initiated by a thermal explosion ignited at one end of the specimen and propagates in a self-sustaining manner, usually results in an uncontrolled porous microstructure and impurities. Sintering at elevated pressures, however, results in a decrease in the necessary sintering time as compared to conventional sintering due to consolidation of the medium and offers more control over the fabrication process and phase composition than SHS. In this work, dense and porous NiTi specimens with approximate porosity levels of 0%, 42%, and 50%, respectively, are fabricated via HIPping and characterized in terms of composition and phase transformation characteristics. Mechanical behavior of the HIPped specimens is studied through quasi-static testing in both shape memory and pseudoelastic effect. Results for the porous NiTi in dynamic testing under compressive loading are also presented to illustrate the large energy absorption and strain recovery capabilities associated with porous NiTi SMA

The C-Terminal RGG Domain of Human Lsm4 Promotes Processing Body Formation Stimulated by Arginine Dimethylation

Processing bodies (PBs) are conserved cytoplasmic aggregations of translationally repressed mRNAs assembled with mRNA decay factors. The aggregation of mRNA-protein (mRNP) complexes into PBs involves interactions between low-complexity regions of protein components of the mRNPs. In Saccharomyces cerevisiae, the carboxy (C)-terminal Q/N-rich domain of the Lsm4 subunit of the Lsm1-7 complex plays an important role in PB formation, but the C-terminal domain of Lsm4 in most eukaryotes is an RGG domain rather than Q/N rich. Here we show that the Lsm4 RGG domain promotes PB accumulation in human cells and that symmetric dimethylation of arginines within the RGG domain stimulates this process. A mutant Lsm4 protein lacking the RGG domain failed to rescue PB formation in cells depleted of endogenous Lsm4, although this mutant protein retained the ability to assemble with Lsm1-7, associate with decapping factors, and promote mRNA decay and translational repression. Mutation of the symmetrically dimethylated arginines within the RGG domain impaired the ability of Lsm4 to promote PB accumulation. Depletion of PRMT5, the primary protein arginine methyltransferase responsible for symmetric arginine dimethylation, including Lsm4, resulted in loss of PBs. We also uncovered the histone acetyltransferase 1 (HAT1)-RBBP7 lysine acetylase complex as an interaction partner of the Lsm4 RGG domain but found no evidence of a role for this complex in PB metabolism. Together, our findings suggest a stimulatory role for posttranslational modifications in PB accumulation and raise the possibility that mRNP dynamics are posttranslationally regulated