Enhancing the heavy Higgs signal with jet-jet profile cuts

The jet-jet profile, or detailed manner, in which transverse energy and mass are distributed around the jet-jet system resulting from the hadronic decay of a $Z$ boson in the process Higgs$\to ZZ$ at a proton-proton collider energy of 40\tev is carefully examined. Two observables are defined that can be used to help distinguish the $\ell^+\ell^-$-jet-jet signal from Higgs decay from the ``ordinary'' QCD background arising from the large transverse momentum production of single $Z$ bosons plus the associated jets. By making cuts on these observables, signal to background enhancement factors greater than $100$ can be obtained.Comment: 16 pages, Univ. Florida IFT-93-

Biosystematics of parsley-ferns, Cryptogramma R. Br., in western North America

A biosystematic investigation of Cryptogramma section Cryptogramma in western North America has been directed towards resolution of two separate taxonomic questions. Results of this research support the hypothesis that a previously undescribed diploid (2n = 30 II) taxon, C. cascadensis, is present along with the common and widespread C. acrostichoides. The new species is distinguished by a number of subtle but constant morphological features, including sterile fronds that are soft and deciduous (compared to the coriaceous, evergreen sterile leaves of C. acrostichoides); surficial rather than sunken hydathodes; absence of laminar trichomes, and significantly smaller spores. Data from enzyme electrophoresis confirm the separation of C cascadensis as a distinct species, as 6 of 13 loci scored were "marker loci", with no alleles held in common between the two species. While different populations of the same species were genetically similar, with genetic identities > 0.85, the mean genetic identity for interspecific population comparisons was 0.36, demonstrating a substantial amount of genetic divergence between the two species. Both species were found to be primarily outcrossing, and the existence of marker loci and a high degree of allozymic differentiation, even in mixed populations, suggests that the two species are reproductively isolated. Also investigated was the taxonomy and evolutionary origin of Cryptogamma sitchensis, a taxon previously treated as a variety of C. acrostichoides. Cryptogamma sitchensis was found to be a tetraploid species, with 2n = 60 II, the first report of polyploidy in the genus from North America. Data from enzyme electrophoresis showed fixed heterozygosity, a characteristic of allopolyploid species. Allozyme banding patterns showed that C. sitchensis combines genomes of C. acrostichoides and another distinct species not present in North America. Morphological characters, particularly the dissection of sterile leaves, suggested that this second parent is the eastern Asian C. raddeana. Frequent triploid hybrids, which can be identified by their abortive spores, occur where the ranges of C. sitchensis and C acrostichoides overlap. Hybrids blur the morphological distinctions between the two species, and are probably responsible for leading earlier workers to conclude that the taxa are only varietally distinct. These results have implications for systematic treatment of other taxa in section Cryptogramma, suggesting that the best taxonomic approach may be to treat geographic segregates as distinct species, rather than as varieties or subspecies of a single circumboreal species, C. crispa, as has been proposed by some workers

Extensive loss of translational genes in the structurally dynamic mitochondrial genome of the angiosperm Silene latifolia

<p>Abstract</p> <p>Background</p> <p>Mitochondrial gene loss and functional transfer to the nucleus is an ongoing process in many lineages of plants, resulting in substantial variation across species in mitochondrial gene content. The Caryophyllaceae represents one lineage that has experienced a particularly high rate of mitochondrial gene loss relative to other angiosperms.</p> <p>Results</p> <p>In this study, we report the first complete mitochondrial genome sequence from a member of this family, <it>Silene latifolia</it>. The genome can be mapped as a 253,413 bp circle, but its structure is complicated by a large repeated region that is present in 6 copies. Active recombination among these copies produces a suite of alternative genome configurations that appear to be at or near "recombinational equilibrium". The genome contains the fewest genes of any angiosperm mitochondrial genome sequenced to date, with intact copies of only 25 of the 41 protein genes inferred to be present in the common ancestor of angiosperms. As observed more broadly in angiosperms, ribosomal proteins have been especially prone to gene loss in the <it>S. latifolia </it>lineage. The genome has also experienced a major reduction in tRNA gene content, including loss of functional tRNAs of both native and chloroplast origin. Even assuming expanded wobble-pairing rules, the mitochondrial genome can support translation of only 17 of the 61 sense codons, which code for only 9 of the 20 amino acids. In addition, genes encoding 18S and, especially, 5S rRNA exhibit exceptional sequence divergence relative to other plants. Divergence in one region of 18S rRNA appears to be the result of a gene conversion event, in which recombination with a homologous gene of chloroplast origin led to the complete replacement of a helix in this ribosomal RNA.</p> <p>Conclusions</p> <p>These findings suggest a markedly expanded role for nuclear gene products in the translation of mitochondrial genes in <it>S. latifolia </it>and raise the possibility of altered selective constraints operating on the mitochondrial translational apparatus in this lineage.</p

Unification of Gauge Couplings in the E(6)SSM

We argue that in the two-loop approximation gauge coupling unification in the exceptional supersymmetric standard model can be achieved for any phenomenologically reasonable value of strong gauge coupling at the electroweak scale consistent with the experimentally measured central value.Comment: Parallel talk at SUSY09, Boston, USA, June 2009, 5 page

Development of an inexpensive tire softening agent from readily available materials to improve traction in race car tires

Developing inexpensive tire softeners can prolong the life of tires and save people money that would be spent on new replacement tires. We have conducted two tests on the treated and untreated tires: the hardness test and the grip test. First, tire hardness was measured with a durometer on a tire that was treated with hot lap and a tire that was not. The tire that was treated with hot lap was slightly softer than the untreated tire substantiating the tire softener\u27s claim. Next, we will be cutting pieces out of the tire (also called omegas) and running them through an instron machine. This machine stretches the omegas at a certain frequency and reports back the hysteresis. The higher the hysteresis, the better the grip. Testing is ongoing, but initial results show that the tire softners did make the tires softer

Development of X-TOOLSS: Preliminary Design of Space Systems Using Evolutionary Computation

Evolutionary computational (EC) techniques such as genetic algorithms (GA) have been identified as promising methods to explore the design space of mechanical and electrical systems at the earliest stages of design. In this paper the authors summarize their research in the use of evolutionary computation to develop preliminary designs for various space systems. An evolutionary computational solver developed over the course of the research, X-TOOLSS (Exploration Toolset for the Optimization of Launch and Space Systems) is discussed. With the success of early, low-fidelity example problems, an outline of work involving more computationally complex models is discussed

Status of the LUX Dark Matter Search

The Large Underground Xenon (LUX) dark matter search experiment is currently being deployed at the Homestake Laboratory in South Dakota. We will highlight the main elements of design which make the experiment a very strong competitor in the field of direct detection, as well as an easily scalable concept. We will also present its potential reach for supersymmetric dark matter detection, within various timeframes ranging from 1 year to 5 years or more.Comment: 4 pages, in proceedings of the SUSY09 conferenc

Static Partitioning vs Dynamic Sharing of Resources in Simultaneous MultiThreading Microarchitectures

Simultaneous MultiThreading (SMT) achieves better system resource utilization and higher performance because it exploits Thread-Level Parallelism (TLP) in addition to "conventional" Instruction-Level Parallelism (ILP). Theoretically, system resources in every pipeline stage of an SMT microarchitecture can be dynamically shared. However, in commercial applications, all the major queues are statically partitioned. From an implementation point of view, static partitioning of resources is easier to implement and has a lower hardware overhead and power consumption. In this paper, we strive to quantitatively determine the trade-off between static partitioning and dynamic sharing. We find that static partitioning of either the instruction fetch queue (IFQ) or the reorder buffer (ROB) is not sufficient if implemented alone (3% and 9% performance decrease respectively in the worst case comparing with dynamic sharing), while statically partitioning both the IFQ and the ROB could achieve an average performance gain of 9% at least, and even reach 148% when running with floating-point benchmarks, when compared with dynamic sharing. We varied the number of functional units in our efforts to isolate the reason for this performance improvement. We found that static partitioning both queues outperformed all the other partitioning mechanisms under the same system configuration. This demonstrates that the performance gain has been achieved by moving from dynamic sharing to static partitioning of the system resources

The Gamma Ray Detection Capabilities of the Alpha Magnetic Spectrometer

The modeled performance of the Alpha Magnetic Spectrometer (AMS) as a high energy (0.3 to 100 GeV) gamma-ray detector is described, and its gamma ray astrophysics objectives are discussed.Comment: Latex2e file; 33 pages of text, 20 EPS figures. Accepted for publication in Astroparticle Physics. Correction to affiliations; no modifications of tex