417 research outputs found
Standard Transistor Array (STAR). Volume 1: Placement technique
A large scale integration (LSI) technology, the standard transistor array uses a prefabricated understructure of transistors and a comprehensive library of digital logic cells to allow efficient fabrication of semicustom digital LSI circuits. The cell placement technique for this technology involves formation of a one dimensional cell layout and "folding" of the one dimensional placement onto the chip. It was found that, by use of various folding methods, high quality chip layouts can be achieved. Methods developed to measure of the "goodness" of the generated placements include efficient means for estimating channel usage requirements and for via counting. The placement and rating techniques were incorporated into a placement program (CAPSTAR). By means of repetitive use of the folding methods and simple placement improvement strategies, this program provides near optimum placements in a reasonable amount of time. The program was tested on several typical LSI circuits to provide performance comparisons both with respect to input parameters and with respect to the performance of other placement techniques. The results of this testing indicate that near optimum placements can be achieved by use of the procedures incurring severe time penalties
The Quantum Mechanics of Hyperion
This paper is motivated by the suggestion [W. Zurek, Physica Scripta, T76,
186 (1998)] that the chaotic tumbling of the satellite Hyperion would become
non-classical within 20 years, but for the effects of environmental
decoherence. The dynamics of quantum and classical probability distributions
are compared for a satellite rotating perpendicular to its orbital plane,
driven by the gravitational gradient. The model is studied with and without
environmental decoherence. Without decoherence, the maximum quantum-classical
(QC) differences in its average angular momentum scale as hbar^{2/3} for
chaotic states, and as hbar^2 for non-chaotic states, leading to negligible QC
differences for a macroscopic object like Hyperion. The quantum probability
distributions do not approach their classical limit smoothly, having an
extremely fine oscillatory structure superimposed on the smooth classical
background. For a macroscopic object, this oscillatory structure is too fine to
be resolved by any realistic measurement. Either a small amount of smoothing
(due to the finite resolution of the apparatus) or a very small amount of
environmental decoherence is sufficient ensure the classical limit. Under
decoherence, the QC differences in the probability distributions scale as
(hbar^2/D)^{1/6}, where D is the momentum diffusion parameter. We conclude that
decoherence is not essential to explain the classical behavior of macroscopic
bodies.Comment: 17 pages, 24 figure
On induced CPT-odd Chern-Simons terms in 3+1 effective action
This paper was originally designated as Comment to the paper by R. Jackiw and
V. Alan Kostelecky (hep-ph/9901358). We provide an example of the fermionic
system, the superfluid 3He-A, in which the CPT-odd Chern-Simons terms in the
effective action are unambiguously induced by chiral fermions. In this system
the Lorentz and gauge invariances both are violated at high energy, but the
behavior of the system beyond the cut-off is known. This allows us to construct
the CPT-odd action, which combines the conventional 3+1 Chern-Simons term and
the mixed axial-gravitational Chern-Simons term discussed in hep-ph/9905460.
The influence of Chern-Simons term on the dynamics of the effective gauge field
has been experimentally observed in rotating 3He-A.Comment: RevTex, 3 pages, no figures, extended version of Comment to the paper
by R. Jackiw and V. Alan Kostelecky (hep-ph/9901358), to appear in JETP Let
The Effect of Cosmological Background Dynamics on the Spherical Collapse in MOND
The effect of background dynamics of the universe on formation of large scale
structures in the framework of Modified Newtonian Dynamics (MOND) is
investigated. A spherical collapse model is used for modeling the formation of
the structures. This study is done in two extreme cases: ({\it i}) assuming a
universe with a low-density baryonic matter without any cold dark matter and
dark energy; ({\it ii}) a dark energy dominated universe with baryonic matter,
without cold dark matter. We show that for the case ({\it ii}) the structures
virialize at lower redshifts with larger radii compared to the low-density
background universe. The dark energy slow downs the collapse of the structures.
We show that our results are compatible with recent simulations of the
structure formation in MOND.Comment: 16 pages, 4 Figures, accepted by New Astronom
A review of research into business coaching supervision
A systematic search of the coaching literature for original peer-reviewed studies into business coaching supervision yielded seven research reports. Evaluation of these studies showed them to be low in the reporting of methodological rigour. However, as an emerging area of research with great importance for the development of the profession of business coaching these studies provide valuable insights into the functions of supervision and its benefits. Gaps in knowledge and directions for future research are identified. There is a need for future research to be more rigorous in its reporting of methods and analytic procedures, small scale qualitative research that can provide insight into the issues and challenges of coaching supervision in specific contexts, and large scale quantitative research which can provide broader and generalizable understandings into the uses and benefits of supervision
Coupled Maps on Trees
We study coupled maps on a Cayley tree, with local (nearest-neighbor)
interactions, and with a variety of boundary conditions. The homogeneous state
(where every lattice site has the same value) and the node-synchronized state
(where sites of a given generation have the same value) are both shown to occur
for particular values of the parameters and coupling constants. We study the
stability of these states and their domains of attraction. As the number of
sites that become synchronized is much higher compared to that on a regular
lattice, control is easier to effect. A general procedure is given to deduce
the eigenvalue spectrum for these states. Perturbations of the synchronized
state lead to different spatio-temporal structures. We find that a mean-field
like treatment is valid on this (effectively infinite dimensional) lattice.Comment: latex file (25 pages), 4 figures included. To be published in Phys.
Rev.
Cosmic Evolution with Early and Late Acceleration Inspired by Dual Nature of the Ricci Scalar Curvature
In the present paper, it is found that dark energy emerges spontaneously from
the modified gravity. According to cosmological scenario, obtained here, the
universe inflates for sec. in the beginning and late universe
accelerates after 8.58 Gyrs. During the long intermediate period, it
decelerates driven by radiation and subsequently by matter. Emerged
gravitational dark energy mimics quintessence and its density falls by 115
orders from its initial value to its current
value .Comment: 40 pages. To appearin Int. J. Mod. Phys.
The Abnormally Weighting Energy Hypothesis: the Missing Link between Dark Matter and Dark Energy
We generalize tensor-scalar theories of gravitation by the introduction of an
abnormally weighting type of energy. This theory of tensor-scalar anomalous
gravity is based on a relaxation of the weak equivalence principle that is now
restricted to ordinary visible matter only. As a consequence, the convergence
mechanism toward general relativity is modified and produces naturally cosmic
acceleration as an inescapable gravitational feedback induced by the
mass-variation of some invisible sector. The cosmological implications of this
new theoretical framework are studied. From the Hubble diagram cosmological
test \textit{alone}, this theory provides an estimation of the amount of
baryons and dark matter in the Universe that is consistent with the independent
cosmological tests of Cosmic Microwave Background (CMB) and Big Bang
Nucleosynthesis (BBN). Cosmic coincidence is naturally achieved from a equally
natural assumption on the amplitude of the scalar coupling strength. Finally,
from the adequacy to supernovae data, we derive a new intriguing relation
between the space-time dependences of the gravitational coupling and the dark
matter mass, providing an example of crucial constraint on microphysics from
cosmology. This glimpses at an enticing new symmetry between the visible and
invisible sectors, namely that the scalar charges of visible and invisible
matter are exactly opposite.Comment: 24 pages, 6 figures, new version with extended discussions and added
references. Accepted for publication in JCAP (sept. 2008
Phenomenological analysis of K+ meson production in proton-nucleus collisions
Total and differential cross sections from literature, on the production of
K+ mesons in pA interactions at projectile energies between T=0.8 and 2.9 GeV,
covering the transition across the free nucleon-nucleon threshold at 1.58 GeV,
have been investigated. From the target-mass dependence of the production cross
sections no evidence for the expected change of the dominant reaction mechanism
from two-step to direct kaon production was found. At T=1.0 GeV the A
dependences of the total cross sections and of the most recent data from
COSY-Juelich, differential cross sections measured under forward angles, are
strongly different. The invariant K+ production cross sections show an overall
exponential scaling behavior with the squared four-momentum transfer between
the beam proton and the produced K+ meson for t< -0.05 GeV^2 independent of the
beam energy and emission angle. The data from COSY-Juelich reveal a strongly
different t dependence in the region of t>0 GeV^2. Further data at forward
angles and different beam energies should be taken in order to explore this
region of kinematically extreme conditions.Comment: 9 Pages, 11 Figure
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Phenome-wide association study (PheWAS) in EMR-linked pediatric cohorts, genetically links PLCL1 to speech language development and IL5-IL13 to Eosinophilic Esophagitis
Objective: We report the first pediatric specific Phenome-Wide Association Study (PheWAS) using electronic medical records (EMRs). Given the early success of PheWAS in adult populations, we investigated the feasibility of this approach in pediatric cohorts in which associations between a previously known genetic variant and a wide range of clinical or physiological traits were evaluated. Although computationally intensive, this approach has potential to reveal disease mechanistic relationships between a variant and a network of phenotypes. Method: Data on 5049 samples of European ancestry were obtained from the EMRs of two large academic centers in five different genotyped cohorts. Recently, these samples have undergone whole genome imputation. After standard quality controls, removing missing data and outliers based on principal components analyses (PCA), 4268 samples were used for the PheWAS study. We scanned for associations between 2476 single-nucleotide polymorphisms (SNP) with available genotyping data from previously published GWAS studies and 539 EMR-derived phenotypes. The false discovery rate was calculated and, for any new PheWAS findings, a permutation approach (with up to 1,000,000 trials) was implemented. Results: This PheWAS found a variety of common variants (MAF > 10%) with prior GWAS associations in our pediatric cohorts including Juvenile Rheumatoid Arthritis (JRA), Asthma, Autism and Pervasive Developmental Disorder (PDD) and Type 1 Diabetes with a false discovery rate < 0.05 and power of study above 80%. In addition, several new PheWAS findings were identified including a cluster of association near the NDFIP1 gene for mental retardation (best SNP rs10057309, p = 4.33 × 10−7, OR = 1.70, 95%CI = 1.38 − 2.09); association near PLCL1 gene for developmental delays and speech disorder [best SNP rs1595825, p = 1.13 × 10−8, OR = 0.65(0.57 − 0.76)]; a cluster of associations in the IL5-IL13 region with Eosinophilic Esophagitis (EoE) [best at rs12653750, p = 3.03 × 10−9, OR = 1.73 95%CI = (1.44 − 2.07)], previously implicated in asthma, allergy, and eosinophilia; and association of variants in GCKR and JAZF1 with allergic rhinitis in our pediatric cohorts [best SNP rs780093, p = 2.18 × 10−5, OR = 1.39, 95%CI = (1.19 − 1.61)], previously demonstrated in metabolic disease and diabetes in adults. Conclusion: The PheWAS approach with re-mapping ICD-9 structured codes for our European-origin pediatric cohorts, as with the previous adult studies, finds many previously reported associations as well as presents the discovery of associations with potentially important clinical implications
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