1,345 research outputs found
Influência de diferentes substratos na germinação de sementes de leiteira (Tabernamontana Laeta Mart.)
Differential operators on supercircle: conformally equivariant quantization and symbol calculus
We consider the supercircle  equipped with the standard contact
structure. The conformal Lie superalgebra K(1) acts on  as the Lie
superalgebra of contact vector fields; it contains the M\"obius superalgebra
. We study the space of linear differential operators on weighted
densities as a module over . We introduce the canonical isomorphism
between this space and the corresponding space of symbols and find interesting
resonant cases where such an isomorphism does not exist
Operation modes of a hydro-generator as a part of the inverter micro hydropower plant
The paper dwells on the selection problem of power equipment for a stand-alone inverter micro hydropower plant, in particular a hydro-generator, and evaluation of its operation modes. Numerical experiments included the modes calculation of hydroelectric units of the same type with various nominal power, supplied to the consumer according to the unchanged electric load curve. The studies developed requirements for a hydro-turbine and a synchronous generator in terms of a speed range and installed capacity, depending on the load curve. The possibility of using general industrial hydroelectric units with nominal power equal to half-maximum capacity of a typical daily load curve in rural areas was shown
Nonlinear optical materials formed by push-pull (bi)thiophene derivatives functionalized with di(tri)cyanovinyl acceptor groups
Studies of the second-order nonlinear optical susceptibilities of six NLOphores bearing di(tri)cyanovinyl acceptor groups linked to (bi)thiophene heterocyclic donor systems were performed for the first time in polymethyl methacrylate (PMMA) matrices with a 1064 nm laser working in the 20 ns time pulse regime. Absorption spectra and DFT calculations were also performed. This multidisciplinary study showed that modulation of the optical (linear and nonlinear) properties can be achieved by increasing the length of the -conjugated heterocyclic system (thiophene vs. bithiophene), the strength of the electron donor groups (HMeO/EtOEt2N) as well as the strength of the electron acceptor moieties (DCV vs. TCV, two vs. three electron withdrawing cyano groups). Due to the relatively high second-order susceptibilities (0.08 to 6.45 pm/V), the studied push-pull chromophores can be denote as very potent NLOphores.Fundação para a Ciência e a Tecnologia (FCT
Cross-over behaviour in a communication network
We address the problem of message transfer in a communication network. The
network consists of nodes and links, with the nodes lying on a two dimensional
lattice. Each node has connections with its nearest neighbours, whereas some
special nodes, which are designated as hubs, have connections to all the sites
within a certain area of influence. The degree distribution for this network is
bimodal in nature and has finite variance. The distribution of travel times
between two sites situated at a fixed distance on this lattice shows fat
fractal behaviour as a function of hub-density. If extra assortative
connections are now introduced between the hubs so that each hub is connected
to two or three other hubs, the distribution crosses over to power-law
behaviour. Cross-over behaviour is also seen if end-to-end short cuts are
introduced between hubs whose areas of influence overlap, but this is much
milder in nature. In yet another information transmission process, namely, the
spread of infection on the network with assortative connections, we again
observed cross-over behaviour of another type, viz. from one power-law to
another for the threshold values of disease transmission probability. Our
results are relevant for the understanding of the role of network topology in
information spread processes.Comment: 12 figure
Physics at a 100 TeV pp collider: Higgs and EW symmetry breaking studies
This report summarises the physics opportunities for the study of Higgs
bosons and the dynamics of electroweak symmetry breaking at the 100 TeV pp
collider.Comment: 187 pages, 94 figures. Chapter 2 of the "Physics at the FCC-hh"
  Repor
A new application of reduced Rayleigh equations to electromagnetic wave scattering by two-dimensional randomly rough surfaces
The small perturbations method has been extensively used for waves scattering
by rough surfaces. The standard method developped by Rice is difficult to apply
when we consider second and third order of scattered fields as a function of
the surface height. Calculations can be greatly simplified with the use of
reduced Rayleigh equations, because one of the unknown fields can be
eliminated. We derive a new set of four reduced equations for the scattering
amplitudes, which are applied to the cases of a rough conducting surface, and
to a slab where one of the boundary is a rough surface. As in the
one-dimensional case, numerical simulations show the appearance of enhanced
backscattering for these structures.Comment: RevTeX 4 style, 38 pages, 16 figures, added references and comments
  on the satellites peak
Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV
Motivated by hints for a light Standard Model-like Higgs boson and a shift in
experimental attention towards electroweak supersymmetry particle production at
the CERN LHC, we update in this paper our precision predictions at
next-to-leading order of perturbative QCD matched to resummation at the
next-to-leading logarithmic accuracy for direct gaugino pair production in
proton-proton collisions with a center-of-mass energy of 8 TeV. Tables of total
cross sections are presented together with the corresponding scale and parton
density uncertainties for benchmark points adopted recently by the experimental
collaborations, and figures are presented for up-to-date model lines attached
to them. Since the experimental analyses are currently obtained with parton
showers matched to multi-parton matrix elements, we also analyze the precision
of this procedure by comparing invariant-mass and transverse-momentum
distributions obtained in this way to those obtained with threshold and
transverse-momentum resummation.Comment: 28 pages, 7 figures, 9 tables; version to appear in JHE
Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report
This Report summarizes the proceedings of the 2013 Les Houches workshop on
Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for
calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections
and (2) the comparison of those cross sections with LHC data from Run 1, and
projections for future measurements in Run 2.Comment: Proceedings of the Standard Model Working Group of the 2013 Les
  Houches Workshop, Physics at TeV Colliders, Les houches 3-21 June 2013. 200
  page
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