6,207 research outputs found
Early b physics at CMS
The CMS experiment at the Large Hadron Collider collected in the first months
of operation a luminosity of about 300/nb. The first results in the context of
the B physics obtained with these data are presented. The di-muon resonances
from J/psi and Y decays are presented and their total and differential
cross-sections measured. The inclusive B production have also being
investigated and two independent measurements are reported. Muons in jets are
used as a way to identify events with B content, the kinematic properties
(ptRel) of the muons are used to separate the B production from other processes
producing muons in jets. The second measurement of inclusive B production is
done using b-tagging techniques and higher energy jets. The two measurements
cover different phase spaces, comparison with LO and NLO prediction are also
presented.Comment: HCP2010 proceedings. CMS CR-2010/19
Interactions of Coloured Heavy Stable Particles in Matter
In this paper we present a physics model for the interactions of stable heavy
hadrons containing a heavy parton with matter. The model presented is a natural
continuation of the work started in hep-ex/0404001. However, changes and
generalisations have been made allowing for the description of a broader scope
of physics scenarios. As a special case the model is tested on the cases of
stable gluino and stop hadrons, thus covering both stable colour triplet and
octet states. Conclusions are drawn regarding the phenomenology of these cases
including how to distinguish between them
Periodic solutions to the Cahn-Hilliard equation in the plane
In this paper we construct entire solutions to the Cahn-Hilliard equation
in the Euclidean
plane, where is the standard double-well potential . Such solutions have a non-trivial profile that shadows a Willmore
planar curve, and converge uniformly to as . These
solutions give a counterexample to the counterpart of Gibbons' conjecture for
the fourth-order counterpart of the Allen-Cahn equation. We also study the
-derivative of these solutions using the special structure of Willmore's
equation
Observability of R-Hadrons at the LHC
Heavy long lived charged particles are predicted in several theories extending the Standard Model. If such particles are coloured they show up as hadrons. These hadrons can be detected in LHC experiments with the very first data exploiting their unique signatures of slow, high momentum particles
Synergies of planning for forests and planning for Natura 2000: Evidences and prospects from northern Italy
Improvements in the management of Natura 2000 sites are essential to achieve the targets set out by the Habitats and Birds Directives of the European Union. A current focus is on the development of management plans, which are fundamental instruments in the implementation of conservation measures. This study explores the viability of using existing forest plans to assist in this purpose. As case study, we consider the regulatory framework of the Veneto Region, northern Italy. We collected quantitative and qualitative data on forest plans at the regional and at three sub-regional spatial scales: local, district, and biogeographical. Forest plans cover about 54% of the terrestrial area of Natura 2000 sites in Veneto, and 75% of Sites of Community Importance in the Alpine biogeographical region. At the local scale of analysis, metrics from forest plans represent a valuable historical record which can be used to interpret the current state and future trends, especially for forests with long management records. These data can be used to assess biodiversity indicators for the monitoring of Natura 2000 forest and non-forest habitats, in compliance with Article 17 of the Habitats Directive. Moreover, the heterogeneous stand conditions which are promoted by some forest management approaches can improve the conservation efforts for some habitats and species. The scale of local forest plans are typically the most appropriate for implementing habitat management strategies. From this study, we conclude that management authorities should take advantage of the wide spatial coverage and distribution of existing forest plans, especially in mountain areas inside and outside the Natura 2000 network, for the successful conservation of European Union habitats and species
Visible light driven photoanodes for water oxidation based on novel r-GO/\u3b2-Cu2V2O7/TiO2 nanorods composites
This paper describes the preparation and the photoelectrochemical performances of
visible light driven photoanodes based on novel r-GO/-Cu2V2O7/TiO2 nanorods/composites.
-Cu2V2O7 was deposited on both fluorine doped tin oxide (FTO) and TiO2 nanorods (NRs)/FTO by
a fast and convenient Aerosol Assisted Spray Pyrolysis (AASP) procedure. Ethylenediamine (EN),
ammonia and citric acid (CA) were tested as ligands for Cu2+ ions in the aerosol precursors solution.
The best-performing deposits, in terms of photocurrent density, were obtained when NH3 was used
as ligand. When -Cu2V2O7 was deposited on the TiO2 NRs a good improvement in the durability
of the photoanode was obtained, compared with pure -Cu2V2O7 on FTO. A further remarkable
improvement in durability and photocurrent density was obtained upon addition, by electrophoretic
deposition, of reduced graphene oxide (r-GO) flakes on the -Cu2V2O7/TiO2 composite material.
The samples were characterized by X-ray Photoelectron Spectroscopy (XPS), Raman, High Resolution
Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM), Wide Angle
X-ray Diffraction (WAXD) and UV\u2013Vis spectroscopies. The photoelectrochemical (PEC) performances
of -Cu2V2O7 on FTO, -Cu2V2O7/TiO2 and r-GO/-Cu2V2O7/TiO2 were tested in visible light by
linear voltammetry and Electrochemical Impedance Spectroscopy (EIS) measurements
Analysis of heat kernel highlights the strongly modular and heat-preserving structure of proteins
In this paper, we study the structure and dynamical properties of protein
contact networks with respect to other biological networks, together with
simulated archetypal models acting as probes. We consider both classical
topological descriptors, such as the modularity and statistics of the shortest
paths, and different interpretations in terms of diffusion provided by the
discrete heat kernel, which is elaborated from the normalized graph Laplacians.
A principal component analysis shows high discrimination among the network
types, either by considering the topological and heat kernel based vector
characterizations. Furthermore, a canonical correlation analysis demonstrates
the strong agreement among those two characterizations, providing thus an
important justification in terms of interpretability for the heat kernel.
Finally, and most importantly, the focused analysis of the heat kernel provides
a way to yield insights on the fact that proteins have to satisfy specific
structural design constraints that the other considered networks do not need to
obey. Notably, the heat trace decay of an ensemble of varying-size proteins
denotes subdiffusion, a peculiar property of proteins
Multimap targeted free energy estimation
We present a new method to compute free energies at a quantum mechanical (QM)
level of theory from molecular simulations using cheap reference potential
energy functions, such as force fields. To overcome the poor overlap between
the reference and target distributions, we generalize targeted free energy
perturbation (TFEP) to employ multiple configuration maps. While TFEP maps have
been obtained before from an expensive training of a normalizing flow neural
network (NN), our multimap estimator allows us to use the same set of QM
calculations to both optimize the maps and estimate the free energy, thus
removing almost completely the overhead due to training. A multimap extension
of the multistate Bennett acceptance ratio estimator is also derived for cases
where samples from two or more states are available. Furthermore, we propose a
one-epoch learning policy that can be used to efficiently avoid overfitting
when computing the loss function is expensive compared to generating data.
Finally, we show how our multimap approach can be combined with enhanced
sampling strategies to overcome the pervasive problem of poor convergence due
to slow degrees of freedom. We test our method on the HiPen dataset of
drug-like molecules and fragments, and we show that it can accelerate the
calculation of the free energy difference of switching from a force field to a
DFTB3 potential by about 3 orders of magnitude compared to standard FEP and by
a factor of about 8 compared to previously published nonequilibrium
calculations.Comment: Added Algorithm 1, wall-clock timings, additional uncertainty
estimates, and other minor edits. Main Text: 12 pages, 5 figures, 7
equations. Supplemental Material: 17 pages, 5 figures, 22 equation
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