2,110 research outputs found
A Probabilistic Linear Genetic Programming with Stochastic Context-Free Grammar for solving Symbolic Regression problems
Traditional Linear Genetic Programming (LGP) algorithms are based only on the
selection mechanism to guide the search. Genetic operators combine or mutate
random portions of the individuals, without knowing if the result will lead to
a fitter individual. Probabilistic Model Building Genetic Programming (PMB-GP)
methods were proposed to overcome this issue through a probability model that
captures the structure of the fit individuals and use it to sample new
individuals. This work proposes the use of LGP with a Stochastic Context-Free
Grammar (SCFG), that has a probability distribution that is updated according
to selected individuals. We proposed a method for adapting the grammar into the
linear representation of LGP. Tests performed with the proposed probabilistic
method, and with two hybrid approaches, on several symbolic regression
benchmark problems show that the results are statistically better than the
obtained by the traditional LGP.Comment: Genetic and Evolutionary Computation Conference (GECCO) 2017, Berlin,
German
Absorption and eigenmode calculation for one-dimensional periodic metallic structures using the hydrodynamic approximation
We develop a modal method that solves Maxwell's equations in the presence of
the linearized hydrodynamic correction. Using this approach, it is now possible
to calculate the full diffraction for structures with period of the order of
the plasma wavelength, including not only the transverse but also the
longitudinal modes appearing above the plasma frequency. As an example for
using this method we solve the diffraction of a plane wave near the plasma
frequency from a bi-metallic layer, modeled as a continuous variation of the
plasma frequency. We observe absorption oscillations around the plasma
frequency. The lower frequency absorption peaks and dips correspond to lowest
longitudinal modes concentrated in the lower plasma frequency region. As the
frequency is increased, higher order longitudinal modes are excited and extent
to the region of higher plasma frequency. Moreover, examination of the
propagation constants of these modes reveals that the absorption peaks and dips
are directly related to the direction of phase propagation of the longitudinal
modes. Furthermore, we formulate a variant of the Plane Wave Expansion method,
and used it to calculate the dispersion diagram of such longitudinal modes in a
periodically modulated plasma frequency layer
Gauged compact Q-balls and Q-shells in a multi-component model
We study a multicomponent model's scalar electrodynamics. The model
contains Q-balls/shells, which are non-topological compact solitons with time
dependency . Two coupled models can decouple locally if
one of their fields takes the vacuum value. Because of the compacton
nature of solutions, Q-shells can shelter another compact Q-ball or Q-shell
within their hollow region. Even if compactons do not overlap, they can
interact through the electromagnetic field. We investigate how the size of
multi-compacton formations is affected by electric charge. We are interested in
structures with non-zero or zero total net charge.Comment: 23 pages, 8 figure
Taxonomy of <i>Baetis</i> Leach in Israel (Ephemeroptera, Baetidae).
The taxonomy and systematics of the genus <i>Baetis</i> Leach (Ephemeroptera: Baetidae) in Israel is clarified for the first time as part of an ongoing comprehensive survey of the Israeli mayfly fauna. Six clearly defined species are currently recognized in Israel, four of which are described here as new to science. The validity of all species is supported by a molecular analysis of the mitochondrial COI gene. A key for the identification of the Israeli species based on the nymphal stage is provided, as well as data on their distribution patterns and ecology. The local fauna represents four Palearctic species groups, three of which reach their limit of distribution range in Israel. <i>Baetis</i> species typically inhabit lotic, pristine habitats in northern Israel, with few exceptions for some species that can be found in the Dead Sea area or in ephemeral ponds
Preservation of Glucose Metabolism in Caudate Region at the Terminal Stage of Late-Infantile Neuronal Ceroid-Lipofuscinosis
開始ページ、終了ページ: 冊子体のページ付
A simple hepatic cyst with elevated serum and cyst fluid CA19-9 levels: a case report
<p>Abstract</p> <p>Introduction</p> <p>Simple hepatic cysts rarely cause symptoms, however, occasionally they become symptomatic due to mass effect, rupture, hemorrhage, and infection. We report a patient with a large hepatic cyst with elevated serum and cyst fluid CA19-9 levels. We studied serum and cyst fluid CA19-9 levels in this patient, before and after the intracystic instillation of minocycline hydrochloride.</p> <p>Case presentation</p> <p>A 76-year-old Japanese woman was diagnosed as having an infected hepatic cyst, by physical examination and enhanced abdominal computed tomography. Serum (170 U/ml; reference: < 37 U/ml) and hepatic cyst fluid (371 U/ml) CA19-9 levels were elevated. After the intracystic instillation of minocycline hydrochloride, necrotic cells in the cyst were drained, and it totally collapsed after 1 week. Cyst fluid CA19-9 levels increased remarkably after the intracystic instillation of minocycline hydrochloride, while serum CA19-9 levels decreased significantly.</p> <p>Conclusion</p> <p>Our study is the first report to reveal the influence of intracystic instillation of minocycline hydrochloride on serum and cyst fluid CA19-9 levels in a patient with a simple hepatic cyst.</p
Trace element and isotopic characteristics of inclusions in the Yamato ordinary chondrites Y-75097, Y-793241 and Y-794046
Igneous inclusions and hosts of the Yamato ordinary chondrites Y-75097 (L6), Y-793241 (L6) and Y-794046 (H5) were analyzed for lithophile trace elements, and Rb-Sr, rare gas and oxygen isotopes, together with preliminary petrographic examinations. On a three oxygen-isotope plot, all the inclusions lie near the H-chondrite field. The Y-75097 host and inclusion were severely shocked and the Rb-Sr systematics were disturbed by a 500Ma event which was defined by the K-Ar age. The Y-793241 host and inclusion are unshocked and have an old K-Ar age of 4270±170Ma and undisturbed Rb-Sr systematics for the bulk meteorite. Both Y-75097 and Y-793241 inclusions have similar chemical compositions and mineral assemblages consisting mainly of olivine (Fa_), and minor plagioclase (An_), chlor-apatite, merrillite and chromite. Olivines in both inclusions equilibrated with those of their L6 hosts. The two inclusion mantles consisting of mainly olivine and plagioclase show a highly fractionated REE pattern with middle REE depletion and a large positive Eu anomaly (50-100 times chondritic) (V-shaped). A model calculation suggests that this remarkable REE fractionation was produced by thermal equilibration with the phosphate-rich cores of inclusions during the igneous formation and the metamorphic event. The Y-794046 inclusion comprises abundant anhedral olivines (Fa_), fractured pyroxenes (Fs_) and microcrystalline plagioclase (An_Ab_Or_). The inclusion did not equilibrate with its host which has less Fe-rich olivines (Fa_) and more Fe in pyroxenes (Fs_). The inclusion shows an unfractionated REE pattern. We suggest that the three inclusions formed by melting of differentiated precursor materials carrying unfractionated REE. They were then incorporated into the L-or H-chondrite parent bodies and subjected to the early thermal metamorphism, which eventually overprinted the fractionated REE in the Y-75097 and Y-793241 inclusions by solid/solid equilibrium partitioning. The Y-794046 inclusion was subjected to less extensive equilibration, so that REE abundances remained unfractionated
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