4,235 research outputs found
The CDF MiniPlug Calorimeters at the Tevatron
Two MiniPlug calorimeters, designed to measure the energy and lateral
position of particles in the pseudorapidity region of 3.6<|eta|<5.1 of the CDF
detector, have been installed as part of the Run II CDF upgrade at the Tevatron
collider. Detector performance and first results from collision data
are presented.Comment: Presented at `Frontier Detectors for Frontier Physics; 9th Pisa
Meeting on Advanced Detectors', Biodola, Italy, 25-31 May 2003. 2 page
Factors Responsible for the Stability and the Existence of a Clean Energy Gap of a Silicon Nanocluster
We present a critical theoretical study of electronic properties of silicon
nanoclusters, in particular the roles played by symmetry, relaxation, and
hydrogen passivation on the the stability, the gap states and the energy gap of
the system using the order-N [O(N)] non-orthogonal tight-binding molecular
dynamics and the local analysis of electronic structure.Comment: 26 pages including figure
Bearing capacity charts of soft soil reinforced by deep mixing
A series of preliminary design charts were developed to predict the bearing capacity of fully and partially penetrated deep mixing (DM) of soft soil. The charts were produced by a new numerical analysis tool based on discontinuity layout optimisation (DLO) in which a previously proposed homogenisation method was used to define the improvement area. To measure the applicability of implementation of the homogenisation method in the DLO, a series of validation processes was performed against several previous studies under uniform soil strength. A new empirical solution was developed from the DLO method using the homogenisation method for the bearing capacity of soft ground under uniform soil strength, improved by the fully penetrated DM method. Results produced by the DLO approach were compared with existing analytical solutions and better agreement was found from the present model. The charts consider variation in improvement area ratio, column length and strength, and foundation width for the fully and partially penetrated DM cases. The simulations were related to real field cases in which the strength characteristics of soft soil increase with depth. An example is given to demonstrate use of the charts
High glucose inhibits human epidermal keratinocyte proliferation for cellular studies on diabetes mellitus
In order to more clarify the delayed wound healing in diabetes mellitus, we cultured the human epidermal keratinocytes in both 6 mM (control group) and 12 mM glucose (high-glucose group) of ‘complete’ MCDB 153 medium. Hyperglycaemia slowed the rate of their proliferation and inhibited their DNA synthesis and the production of total proteins. By 1 month after primary seeding in high-glucose group, the cells ceased their proliferation, whereas the cells in control group grew for more than 40 days. Mean population doublings in high-glucose group was 5·27 (vs. 7·25 in control, P = 0·001), and mean population doubling time during 1 month in high glucose group was 5·43 days (vs. 3·65 days in control, P = 0·02). They indicate that prolonged exposure to high glucose decreases the replicative life span of human epidermal keratinocytes in vitro. Furthermore, analysis of fatty acid contents in membrane phospholipids with thin-layer and gas chromatography showed no difference between the cultured keratinocytes in both conditions. Immunocytochemical staining of glucose transporter 1 shows that 28·1% of cells in high-glucose group were almost twice positive of those in control group (13·2%, P = 0·008). The mechanism of the ill effects of high glucose on epidermal keratinocytes is not so far clear, but it indicates the possibility of any direct effect of hyperglycaemia on glucose metabolism without changing lipid metabolism on cell membrane. The high-glucose group presented in this report can be available as an in vitro valuable study model of skin epidermal condition on diabetes mellitus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72307/1/j.1742-4801.2005.00148.x.pd
Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV
We report on a search for anomalous production of events with at least two
charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1
sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a
signal region containing low background from Standard Model processes. To avoid
bias, we fix the final cuts before examining the event yield in the signal
region using control regions to test the Monte Carlo predictions. We observe no
events in the signal region, consistent with an expectation of
0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new
physics processes in both a signature-based context as well as within a
representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to
figures and updated and expanded reference
Strong interface-induced spin-orbit coupling in graphene on WS2
Interfacial interactions allow the electronic properties of graphene to be
modified, as recently demonstrated by the appearance of satellite Dirac cones
in the band structure of graphene on hexagonal boron nitride (hBN) substrates.
Ongoing research strives to explore interfacial interactions in a broader class
of materials in order to engineer targeted electronic properties. Here we show
that at an interface with a tungsten disulfide (WS2) substrate, the strength of
the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The
induced SOI leads to a pronounced low-temperature weak anti-localization (WAL)
effect, from which we determine the spin-relaxation time. We find that
spin-relaxation time in graphene is two-to-three orders of magnitude smaller on
WS2 than on SiO2 or hBN, and that it is comparable to the intervalley
scattering time. To interpret our findings we have performed first-principle
electronic structure calculations, which both confirm that carriers in
graphene-on-WS2 experience a strong SOI and allow us to extract a
spin-dependent low-energy effective Hamiltonian. Our analysis further shows
that the use of WS2 substrates opens a possible new route to access topological
states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines.
Final version with expanded discussion of the relation between theory and
experiments to be published in Nature Communication
Measurement of the lepton charge asymmetry in W-boson decays produced in p-pbar collisions
We describe a measurement of the charge asymmetry of leptons from W boson
decays in the rapidity range 0 enu, munu events from
110+/-7 pb^{-1}of data collected by the CDF detector during 1992-95. The
asymmetry data constrain the ratio of d and u quark momentum distributions in
the proton over the x range of 0.006 to 0.34 at Q2 \approx M_W^2. The asymmetry
predictions that use parton distribution functions obtained from previously
published CDF data in the central rapidity region (0.0<|y_l|<1.1) do not agree
with the new data in the large rapidity region (|y_l|>1.1).Comment: 13 pages, 3 tables, 1 figur
Measurement of the Decay Amplitudes of B0 --> J/psi K* and B0s --> J/psi phi Decays
A full angular analysis has been performed for the pseudo-scalar to
vector-vector decays, B0 --> J/psi K* and B_s --> J/psi phi, to determine the
amplitudes for decays with parity-even longitudinal and transverse polarization
and parity-odd transverse polarization. The measurements are based on 190 B0
candidates and 40 B_s candidates collected from a data set corresponding to 89
inverse pb of pbarp collisions at root(s) = 1.8 TeV at the Fermilab Tevatron.
In both decays the decay amplitude for longitudinal polarization dominates and
the parity-odd amplitude is found to be small.Comment: 7 pages, 3 figures, 1 tabl
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