445 research outputs found
Intertwining Laplace Transformations of Linear Partial Differential Equations
We propose a generalization of Laplace transformations to the case of linear
partial differential operators (LPDOs) of arbitrary order in R^n. Practically
all previously proposed differential transformations of LPDOs are particular
cases of this transformation (intertwining Laplace transformation, ILT). We
give a complete algorithm of construction of ILT and describe the classes of
operators in R^n suitable for this transformation.
Keywords: Integration of linear partial differential equations, Laplace
transformation, differential transformationComment: LaTeX, 25 pages v2: minor misprints correcte
東北福祉大学研究紀要[奥付]:第36巻
xvi, 619 p. : il.; 24 c
Sums of products of Ramanujan sums
The Ramanujan sum is defined as the sum of -th powers of the
primitive -th roots of unity. We investigate arithmetic functions of
variables defined as certain sums of the products
, where are polynomials with
integer coefficients. A modified orthogonality relation of the Ramanujan sums
is also derived.Comment: 13 pages, revise
Composition of KBO (50000) Quaoar
Aims. The objective of this work is to investigate the physical properties of objects beyond Neptune-the new frontiers of the Solar System-and in particular to study the surface composition of (50 000) Quaoar, a classical Transneptunian (or Kuiper Belt) object. Because of its distance from the Sun, Quaoar is expected to have preserved, to a degree, its original composition. Our goals are to determine to what degree this is true and to shed light on the chemical evolution of this icy body. Methods. We present new near-infrared (3.6 and 4.5 mu m) photometric data obtained with the Spitzer Space Telescope. These data complement high resolution, low signal-to-noise spectroscopic and photometric data obtained in the visible and near-infrared (0.4-2.3 mu m) at VLT-ESO and provide an excellent set of constraints in the model calculation process. We perform spectral modeling of the entire wavelength range-from 0.3 to 4.5 mu m by means of a code based on the Shkuratov radiative transfer formulation of the slab model. We also attempt to determine the temperature of H(2)O ice making use of the crystalline feature at 1.65 mu m. Results. We present a model confirming previous results regarding the presence of crystalline H(2)O and CH(4) ice, as well as C(2)H(6) and organic materials, on the surface of this distant icy body. We attempt a measurement of the temperature and find that stronger constraints on the composition are needed to obtain a precise determination. Conclusions. Model fits indicate that N(2) may be a significant component, along with a component that is bright at lambda > 3.3 mu m, which we suggest at this time could be amorphous H(2)O ice in tiny grains or thin grain coatings. Irradiated crystalline H(2)O could be the source of small-grained amorphous H(2)O ice. The albedo and composition of Quaoar, in particular the presence of N(2), if confirmed, make this TNO quite similar to Triton and Pluto
Bicrossed products for finite groups
We investigate one question regarding bicrossed products of finite groups
which we believe has the potential of being approachable for other classes of
algebraic objects (algebras, Hopf algebras). The problem is to classify the
groups that can be written as bicrossed products between groups of fixed
isomorphism types. The groups obtained as bicrossed products of two finite
cyclic groups, one being of prime order, are described.Comment: Final version: to appear in Algebras and Representation Theor
Extended BRST invariance in topological Yang Mills theory revisited
Extended BRST invariance (BRST plus anti-BRST invariances) provides in
principle a natural way of introducing the complete gauge fixing structure
associated to a gauge field theory in the minimum representation of the
algebra. However, as it happens in topological Yang Mills theory, not all gauge
fixings can be obtained from a symmetrical extended BRST algebra, where
antighosts belong to the same representation of the Lorentz group of the
corresponding ghosts. We show here that, at non interacting level, a simple
field redefinition makes it possible to start with an extended BRST algebra
with symmetric ghost antighost spectrum and arrive at the gauge fixing action
of topological Yang Mills theory.Comment: Interaction terms heve been included in all the calculations. Two
references added. Version to be published in Phys. Rev. D. 7 pages, Latex, no
figure
The time resolution of the St. Petersburg paradox
A resolution of the St. Petersburg paradox is presented. In contrast to the
standard resolution, utility is not required. Instead, the time-average
performance of the lottery is computed. The final result can be phrased
mathematically identically to Daniel Bernoulli's resolution, which uses
logarithmic utility, but is derived using a conceptually different argument.
The advantage of the time resolution is the elimination of arbitrary utility
functions.Comment: 20 pages, 1 figur
Power, Proximity, and Physiology: Does Income Inequality and Racial Composition Amplify the Impacts of Air Pollution on Life Expectancy in the United States?
This study advances research at the intersection of environmental degradation, social stratification, and population health in the United States. Expanding the theoretical principles of power, proximity, and physiology, we hypothesize that the harmful effect of fine particulate matter on life expectancy is greater in states with higher levels of income inequality and larger black populations. To test our hypothesis, we use two-way fixed effects regression analysis to estimate the effect of a three-way interaction between fine particulate matter, income share of the top ten percent, and the percent of the population that is black on state-level average life expectancy for all US states and the District of Columbia (2000–2014). The findings support our hypothesis: the estimated effect of the three-way interaction on average life expectancy is negative and statistically significant, net of various socioeconomic and demographic controls. Using post-estimation techniques, we visually illustrate that the harmful effect of fine particulate matter on life expectancy is especially pronounced in states with both very high levels of income inequality and very large black populations. We conclude by summarizing the theoretical and substantive implications of our findings, the limitations of the study, and potential next steps in this evolving area of interdisciplinary research
Potential use of pyriproxyfen for control of Aedes aegypti (Diptera: Culicidae) in Iquitos, Peru
Los efectos del pyriproxyfen fueron evaluados contra una población local de Aedes aegypti (L.) en Iquitos, Perú. Los bioensayos mostraron que el pyriproxyfen previene la emergencia de adultos con concentraciones extremadamente bajas (LC50 = 0,012 ppb). No hubo emergencia de adultos de las muestras de agua obtenidas de los tanques de almacenamiento que habían sido tratados con el equivalente de 50-83 ppb (AI) de pyriproxyfen. Cinco meses después del tratamiento, a pesar de las constantes diluciones de estos tanques, las muestras de agua de estas fuentes continuaron siendo letales para las larvas y pupa
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