How Wigner Functions Transform Under Symplectic Maps

It is shown that, while Wigner and Liouville functions transform in an identical way under linear symplectic maps, in general they do not transform identically for nonlinear symplectic maps. Instead there are ``quantum corrections'' whose hbar tending to zero limit may be very complicated. Examples of the behavior of Wigner functions in this limit are given in order to examine to what extent the corresponding Liouville densities are recovered.Comment: 8 pages, 6 figures [RevTeX/epsfig, macro included]. To appear in Proceedings of the Advanced Beam Dynamics Workshop on Quantum Aspects of Beam Physics (Monterey, CA 1998

Using modular decomposition technique to solve the maximum clique problem

In this article we use the modular decomposition technique for exact solving the weighted maximum clique problem. Our algorithm takes the modular decomposition tree from the paper of Tedder et. al. and finds solution recursively. Also, we propose algorithms to construct graphs with modules. We show some interesting results, comparing our solution with Ostergard's algorithm on DIMACS benchmarks and on generated graph

The central elliptical galaxy in fossil groups and formation of BCGs

We study the dominant central giant elliptical galaxies in ``Fossil groups'' using deep optical (R-band) and near infrared (Ks-band) photometry. These galaxies are as luminous as the brightest cluster galaxies (BCGs), raising immediate interest in their link to the formation of BCGs and galaxy clusters. However, despite apparent similarities, the dominant fossil galaxies show non-boxy isophotes, in contrast to the most luminous BCGs. This study suggests that the structure of the brightest group galaxies produced in fossil groups are systematically different to the majority of BCGs. If the fossils do indeed form from the merger of major galaxies including late-types within a group, then their disky nature is consistent with the results of recent numerical simulations of semi-analytical models which suggest that gas rich mergers result in disky isophote ellipticals. We show that fossils form a homogeneous population in which the velocity dispersion of the fossil group is tightly correlated with the luminosity of the dominant elliptical galaxy. This supports the scenario in which the giant elliptical galaxies in fossils can grow to the size and luminosity of BCGs in a group environment. However, the boxy structure of luminous BCGs indicate that they are either not formed as fossils, or have undergone later gas-free mergers within the cluster environment.Comment: 5 pages, 4 figures, Accepted for publication in MNRAS letter

Gene Expression Profile Changes After Short-activating RNA-mediated Induction of Endogenous Pluripotency Factors in Human Mesenchymal Stem Cells

It is now recognized that small noncoding RNA sequences have the ability to mediate transcriptional activation of specific target genes in human cells. Using bioinformatics analysis and functional screening, we screened short-activating RNA (saRNA) oligonucleotides designed to target the promoter regions of the pluripotency reprogramming factors, Kruppel-like factor 4 (KLF4) and c-MYC. We identified KLF4 and c-MYC promoter-targeted saRNA sequences that consistently induced increases in their respective levels of nascent mRNA and protein expression in a time- and dose-dependent manner, as compared with scrambled sequence control oligonucleotides. The functional consequences of saRNA-induced activation of each targeted reprogramming factor were then characterized by comprehensively profiling changes in gene expression by microarray analysis, which revealed significant increases in mRNA levels of their respective downstream pathway genes. Notably, the microarray profile after saRNA-mediated induction of endogenous KLF4 and c-MYC showed similar gene expression patterns for stem cell- and cell cycle-related genes as compared with lentiviral vector-mediated overexpression of exogenous KLF4 and c-MYC transgenes, while divergent gene expression patterns common to viral vector-mediated transgene delivery were also noted. The use of promoter-targeted saRNAs for the activation of pluripotency reprogramming factors could have broad implications for stem cell research

Development And Commercialization of Advanced Wood-Based Composites In Maine

This award is to the University of Maine to support the activity described below for 36 months. The proposal was submitted in response to the Partnerships for Innovation Program Solicitation (NSF 0179).PartnersThe partners for the award include the University of Maine (Lead Institution), Maine Technology Institute, Eastern Maine Development Corporation, State Department of Economic and Community Development, The Manufacturing Extension Partnership, Maine Department of Transportation, Louisiana Pacific, Dow Chemical, State Farm Insurance, Henderson and Bodwell, The Kenway Corporation, Market Development Alliance of the FRP Composites Industry, APA the Engineered Wood Association, National Institutes of Standards and Technology, USDA Forest Products Laboratory.Proposed ActivitiesThe award will support the following activities: (1) strengthen partnerships among the University of Maine, private industry, state organizations, forest product industry organizations, and national laboratories to foster commercialization of composite reinforced wood, (2) develop innovative strategies for commercializing composite reinforced wood hybrids that can become models for other university research centers, establish commercialization projects (reinforced wood composite beams using low-grade hardwoods, disaster-resistant housing using reinforced sheathing panels, novel long-strand composite lumber beams and columns).Proposed InnovationHousing industry in the US accounts for 28% of the total construction industry, and most of the wood used is high-grade conventional wood lumber. The supply of high-grade lumber is declining in the US. Reinforced composite wood will allow the use of low-grade lumber from other species of trees in more abundant supply, and provide skilled jobs in Maine. These products will lower the cost of wood products for housing in the US. Increasing the resistance of housing to disasters such as hurricanes and earthquakes will make a major impact on the economy of the nation.Potential Economic ImpactNinety percent of Maine is forested, and 25% of the state\u27s economy is based on forest resources. The forest economy has traditionally been based on export of raw lumber with unskilled labor and few value added timber products. Other manufacturing jobs have moved from the state recently, leaving unskilled jobs and service industries (e.g., tourism) as the major source of income. Successful commercialization of composite reinforced wood will play a large role in developing a growing state economy. Lower costs for wood products for housing construction will have a major economic impact in the US. Increasing the resistance of housing to disasters will lower the cost of repair, maintenance, and insurance for disasters.Potential Societal ImpactMaine ranks 29th in the nation in terms of advanced degree scientists/engineers and 50th in science/engineering graduate students. The job market for young scientists and engineers is bleak in Maine. The educational program will include entrepreneurial education as well as science and engineering to provide a skilled workforce for the economy surrounding the new wood-based technology/economy. The housing industry amounts to $800 billion/year in the US alone

The Mass Assembly of Fossil Groups of Galaxies in the Millennium Simulation

The evolution of present-day fossil galaxy groups is studied in the Millennium Simulation. Using the corresponding Millennium gas simulation and semi-analytic galaxy catalogues, we select fossil groups at redshift zero according to the conventional observational criteria, and trace the haloes corresponding to these groups backwards in time, extracting the associated dark matter, gas and galaxy properties. The space density of the fossils from this study is remarkably close to the observed estimates and various possibilities for the remaining discrepancy are discussed. The fraction of X-ray bright systems which are fossils appears to be in reasonable agreement with observation, and the simulations predict that fossil systems will be found in significant numbers (3-4% of the population) even in quite rich clusters. We find that fossils assemble a higher fraction of their mass at high redshift, compared to non-fossil groups, with the ratio of the currently assembled halo mass to final mass, at any epoch, being about 10 to 20% higher for fossils. This supports the paradigm whereby fossils represent undisturbed, early-forming systems in which large galaxies have merged to form a single dominant elliptical.Comment: 11 pages, 8 figures, submitted to MNRA