105 research outputs found
Reversible Random Sequential Adsorption of Dimers on a Triangular Lattice
We report on simulations of reversible random sequential adsorption of dimers
on three different lattices: a one-dimensional lattice, a two-dimensional
triangular lattice, and a two-dimensional triangular lattice with the nearest
neighbors excluded. In addition to the adsorption of particles at a rate K+, we
allow particles to leave the surface at a rate K-. The results from the
one-dimensional lattice model agree with previous results for the continuous
parking lot model. In particular, the long-time behavior is dominated by
collective events involving two particles. We were able to directly confirm the
importance of two-particle events in the simple two-dimensional triangular
lattice. For the two-dimensional triangular lattice with the nearest neighbors
excluded, the observed dynamics are consistent with this picture. The
two-dimensional simulations were motivated by measurements of Ca++ binding to
Langmuir monolayers. The two cases were chosen to model the effects of changing
pH in the experimental system.Comment: 9 pages, 10 figure
Assembléias de peixes associados às macrófitas aquáticas em ambientes alagáveis do Pantanal de Poconé, MT, Brasil
Study of the lineshape of the chi(c1) (3872) state
A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations
Measurement of the CKM angle in and decays with
A measurement of -violating observables is performed using the decays
and , where the meson is
reconstructed in one of the self-conjugate three-body final states and (commonly denoted ). The decays are analysed in bins of the -decay phase space, leading
to a measurement that is independent of the modelling of the -decay
amplitude. The observables are interpreted in terms of the CKM angle .
Using a data sample corresponding to an integrated luminosity of
collected in proton-proton collisions at centre-of-mass
energies of , , and with the LHCb experiment,
is measured to be . The hadronic
parameters , , , and ,
which are the ratios and strong-phase differences of the suppressed and
favoured decays, are also reported
Study of the doubly charmed tetraquark T+cc
Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
In search of the epicondylar axis - interobserver variability in landmark identification during computer navigated total knee arthroplasty : a cadaveric study
The accuracy of measurement in computer-assisted total knee arthroplasty is dependent on the quality of data acquisition at the start of the procedure; errors in landmark identification could lead to misalignment and therefore poorer longterm outcomes.Some navigation systems require the surgeon to explicitly identify the femoral epicondyles in order to calculate the trans-epicondylar axis, whereas other systems are able to interpolate the epicondylar location based on a number of points acquired from the distal femoral surface. Significant inter-observer variability in landmark identification has been previously reported in dry bone studies. The purpose of this study was to test the accuracy of identification of the epicondyles during a simulated total knee replacement on a fresh cadaveric specimen.An unfixed fresh cadaveric left lower limb was used to perform a navigated total knee replacement using the Orthopilot® (B|Braun-Aesculap, Tuttlingen, Germany) image-free navigation system.Sixteen surgeons attending an advanced navigation training course were invited to take part. A single consultant surgeon performed initial dissection and pin placement, up to the point of landmark acquisition. Each subject was then asked to use a pointer tool to identify the medial and lateral epicondyles, as they would in an operative situation. Data were recorded by the Orthopilot® system, and exported as a 3D array for further analysis.Initial visualisation with a 3D scatter plot showed that points were evenly distributed within a circular pattern around each epicondyle. The length of a vector between each point on each epicondyle was calculated in turn. The maximum distances between points were 15.6mm for the medial epicondyle, and 19.9mm for the lateral epicondyle.We then calculated the length and angulation of the trans-epicondylar axis (TEA) for each observer, equivalent to the vector between each pair of points (medial and lateral epicondyle). An average TEA was calculated, and the range and standard deviation of angulation were determined. In the x axis the range was 16.3° (–8.3° to 7.9°, SD 5.1°), in the y axis the range was 18.7° (–8.7° to 10°, SD 5.2°) and in the z axis the range was 20.5° (–10.1° to 10.4°, SD 6.5°). Range of recorded TEA length was 64.5 to 74.9mm (mean 70.6mm, SD 3.3mm).We conclude that in this simulated operative scenario, surgeons exhibited considerable variability when locating the epicondyles. Range of angulation of the TEA exceeded 16° (SD >5.1°) in all 3 planes. We cannot recommend the use of a trans-epicondylar axis determined from 2 single points, as a reliable landmark in navigated total knee replacement
Multi-analyte study of circulating cytokines in smokers, with or without chronic obstructive pulmonary disease, and with or without lung cancer, using biochip array technology
Binding of CRP to DNA-dependent RNA polymerase from E. coli: Modulation by cAMP of the interactions with free and DNA-bound holo and core enzyme
The effects of air quality regulations on the location decisions of pollution-intensive manufacturing plants
Regulatory policies, Environmental regulations, Interjurisdictional competition, R38, Q28, H73,
The Most Frequently Cited Journal Articles and Authors in Introductory Psychology Textbooks
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