1,076 research outputs found
High order difference schemes for the system of two space second order nonlinear hyperbolic equations with variable coefficients
AbstractIn this paper, we develop implicit difference schemes of O(k4 + k2h2 + h4), where k > 0, h > 0 are grid sizes in time and space coordinates, respectively, for solving the system of two space dimensional second order nonlinear hyperbolic partial differential equations with variable coefficients having mixed derivatives subject to appropriate initial and boundary conditions. The proposed difference method for the scalar equation is applied for the solution of wave equation in polar coordinates to obtain three level conditionally stable ADI method of O(k4 + k2h2 + h4). Some physical nonlinear problems are provided to demonstrate the accuracy of the implementation
R.K. Narayan: Straddling Metropole and Malgudi
âIn her essay âResistance through Sub/Mission in the Novels of R. K. Narayan,â Hyacinth Cynthia Wyatt argues that âamong Indian authors writing in English, R. K. Narayan was among the first to resist Western cultural dominanceââŠ
Delayed Blanch Phenomenon in Children: Reevaluation Of 5-Year-old Children Originally Tested as Newborns
A follow-up study involving 50 children (who were 5 years old) from an original group of 100 who had been tested as newborns was carried out using the delayed blanch phenomenon. The reaction persisted in 78%. No correlation could be found between personal and family history of allergy and the presence or absence of the delayed blanch phenomenon
A dynamic and multifunctional account of middleârange theories
This article develops a novel account of middleârange theories for combining theoretical and empirical analysis in explanatory sociology. I first revisit Robert K. Mertonâs original ideas on middleârange theories and identify a tension between his developmental approach to middleârange theorizing that recognizes multiple functions of theories in sociological research and his static definition of the concept of middleârange theory that focuses only on empirical testing of theories. Drawing on Merton's ideas on theorizing and recent discussions on mechanismâbased explanations, I argue that this tension can be resolved by decomposing a middleârange theory into three interrelated and evolving components that perform different functions in sociological research: (i) a conceptual framework about social phenomena that is a set of interrelated concepts that evolve in close connection with empirical analysis; (ii) a mechanism schema that is an abstract and incomplete description of a social mechanism; and (iii) a cluster of all mechanismâbased explanations of social phenomena that are based on the particular mechanism schema. I show how these components develop over time and how they serve different functions in sociological theorizing and research. Finally, I illustrate these ideas by discussing Mertonâs theory of the Matthew effect in science and its more recent applications in sociology.This article develops a novel account of middleârange theories for combining theoretical and empirical analysis in explanatory sociology. I first revisit Robert K. Mertonâs original ideas on middleârange theories and identify a tension between his developmental approach to middleârange theorizing that recognizes multiple functions of theories in sociological research and his static definition of the concept of middleârange theory that focuses only on empirical testing of theories. Drawing on Merton's ideas on theorizing and recent discussions on mechanismâbased explanations, I argue that this tension can be resolved by decomposing a middleârange theory into three interrelated and evolving components that perform different functions in sociological research: (i) a conceptual framework about social phenomena that is a set of interrelated concepts that evolve in close connection with empirical analysis; (ii) a mechanism schema that is an abstract and incomplete description of a social mechanism; and (iii) a cluster of all mechanismâbased explanations of social phenomena that are based on the particular mechanism schema. I show how these components develop over time and how they serve different functions in sociological theorizing and research. Finally, I illustrate these ideas by discussing Mertonâs theory of the Matthew effect in science and its more recent applications in sociology.Peer reviewe
Homogeneous nucleation of a non-critical phase near a continuous phase transition
Homogeneous nucleation of a new phase near a second, continuous, transition,
is considered. The continuous transition is in the metastable region associated
with the first-order phase transition, one of whose coexisting phases is
nucleating. Mean-field calculations show that as the continuous transition is
approached, the size of the nucleus varies as the response function of the
order parameter of the continuous transition. This response function diverges
at the continuous transition, as does the temperature derivative of the free
energy barrier to nucleation. This rapid drop of the barrier as the continuous
transition is approached means that the continuous transition acts to reduce
the barrier to nucleation at the first-order transition. This may be useful in
the crystallisation of globular proteins.Comment: 6 pages, 1 figur
Shear free solutions in General Relativity Theory
The Goldberg-Sachs theorem is an exact result on shear-free null geodesics in
a vacuum spacetime. It is compared and contrasted with an exact result for
pressure-free matter: shear-free flows cannot both expand and rotate. In both
cases, the shear-free condition restricts the way distant matter can influence
the local gravitational field. This leads to intriguing discontinuities in the
relation of the General Relativity solutions to Newtonian solutions in the
timelike case, and of the full theory to the linearised theory in the null
case.
It is a pleasure to dedicate this paper to Josh Goldberg.Comment: 17 pages, no figures. For GRG special issue in honor of Josh Goldber
Joint resummation in electroweak boson production
We present a phenomenological application of the joint resummation formalism
to electroweak annihilation processes at measured boson momentum Q_T. This
formalism simultaneously resums at next-to-leading logarithmic accuracy large
threshold and recoil corrections to partonic scattering. We invert the impact
parameter transform using a previously described analytic continuation
procedure. This leads to a well-defined, resummed perturbative cross section
for all nonzero Q_T, which can be compared to resummation carried out directly
in Q_T space. From the structure of the resummed expressions, we also determine
the form of nonperturbative corrections to the cross section and implement
these into our analysis. We obtain a good description of the transverse
momentum distribution of Z bosons produced at the Tevatron collider.Comment: 27 pages, LaTeX, 8 figures as eps files. Some additions to earlier
version, this version as published in Phys. Rev. D66 (2002) 01401
Event Shape/Energy Flow Correlations
We introduce a set of correlations between energy flow and event shapes that
are sensitive to the flow of color at short distances in jet events. These
correlations are formulated for a general set of event shapes, which includes
jet broadening and thrust as special cases. We illustrate the method for
electron-positron annihilation dijet events, and calculate the correlation at
leading logarithm in the energy flow and at next-to-leading-logarithm in the
event shape.Comment: 43 pages, eight eps figures; minor changes, references adde
Recoil and Threshold Corrections in Short-distance Cross Sections
We identify and resum corrections associated with the kinematic recoil of the
hard scattering against soft-gluon emission in single-particle inclusive cross
sections. The method avoids double counting and conserves the flow of partonic
energy. It reproduces threshold resummation for high-p_T single-particle cross
sections, when recoil is neglected, and Q_T-resummation at low Q_T, when
higher-order threshold logarithms are suppressed. We exhibit explicit resummed
cross sections, accurate to next-to-leading logarithm, for electroweak
annihilation and prompt photon inclusive cross sections.Comment: minor modifications of the text, some references added. 51 pages,
LaTeX, 6 figures as eps file
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