78,663 research outputs found
A psychoanalytic concept illustrated: Will, must, may, can â revisiting the survival function of primitive omnipotence
The author explores the linear thread connecting the theory of Freud and Klein, in terms of the central significance of the duality of the life and death instinct and the capacity of the ego to tolerate contact with internal and external reality. Theoretical questions raised by later authors, informed by clinical work with children who have suffered deprivation and trauma in infancy, are then considered. Theoretical ideas are illustrated with reference to observational material of a little boy who suffered deprivation and trauma in infancy. He was first observed in the middle of his first year of life while he was living in foster care, and then later at the age of two years and three months, when he had been living with his adoptive parents for more than a year
Quantum theory of large amplitude collective motion and the Born-Oppenheimer method
We study the quantum foundations of a theory of large amplitude collective
motion for a Hamiltonian expressed in terms of canonical variables. In previous
work the separation into slow and fast (collective and non-collective)
variables was carried out without the explicit intervention of the Born
Oppenheimer approach. The addition of the Born Oppenheimer assumption not only
provides support for the results found previously in leading approximation, but
also facilitates an extension of the theory to include an approximate
description of the fast variables and their interaction with the slow ones.
Among other corrections, one encounters the Berry vector and scalar potential.
The formalism is illustrated with the aid of some simple examples, where the
potentials in question are actually evaluated and where the accuracy of the
Born Oppenheimer approximation is tested. Variational formulations of both
Hamiltonian and Lagrangian type are described for the equations of motion for
the slow variables.Comment: 29 pages, 1 postscript figure, preprint no UPR-0085NT. Latex + epsf
styl
Study of a multiple reserve electrochemical power source
Feasibility of metal oxygen primary batteries for multiple reserve us
Metastability in stochastic dynamics of disordered mean-field models
We study a class of Markov chains that describe reversible stochastic
dynamics of a large class of disordered mean field models at low temperatures.
Our main purpose is to give a precise relation between the metastable time
scales in the problem to the properties of the rate functions of the
corresponding Gibbs measures. We derive the analog of the Wentzell-Freidlin
theory in this case, showing that any transition can be decomposed, with
probability exponentially close to one, into a deterministic sequence of
``admissible transitions''. For these admissible transitions we give upper and
lower bounds on the expected transition times that differ only by a constant.
The distribution rescaled transition times are shown to converge to the
exponential distribution. We exemplify our results in the context of the random
field Curie-Weiss model.Comment: 73pp, AMSTE
Metastability and low lying spectra in reversible Markov chains
We study a large class of reversible Markov chains with discrete state space
and transition matrix . We define the notion of a set of {\it metastable
points} as a subset of the state space \G_N such that (i) this set is reached
from any point x\in \G_N without return to x with probability at least ,
while (ii) for any two point x,y in the metastable set, the probability
to reach y from x without return to x is smaller than
. Under some additional non-degeneracy assumption, we show
that in such a situation: \item{(i)} To each metastable point corresponds a
metastable state, whose mean exit time can be computed precisely. \item{(ii)}
To each metastable point corresponds one simple eigenvalue of which is
essentially equal to the inverse mean exit time from this state. The
corresponding eigenfunctions are close to the indicator function of the support
of the metastable state. Moreover, these results imply very sharp uniform
control of the deviation of the probability distribution of metastable exit
times from the exponential distribution.Comment: 44pp, AMSTe
The Effect of Cooling Rate on the Ductile- Brittle Bend-transition Temperature of Chromium Wire
Effect of cooling rate on ductile-brittle bend-transition temperature of chromium wir
Investigation of mechanical properties of chromium, chromium-rhenium, and derived alloys Twenty-third quarterly progress report, Oct. 1, 1965 - Mar. 31, 1966
Mechanical properties of chromium-rhenium alloy wire
Possible solution of the Coriolis attenuation problem
The most consistently useful simple model for the study of odd deformed
nuclei, the particle-rotor model (strong coupling limit of the core-particle
coupling model) has nevertheless been beset by a long-standing problem: It is
necessary in many cases to introduce an ad hoc parameter that reduces the size
of the Coriolis interaction coupling the collective and single-particle
motions. Of the numerous suggestions put forward for the origin of this
supplementary interaction, none of those actually tested by calculations has
been accepted as the solution of the problem. In this paper we seek a solution
of the difficulty within the framework of a general formalism that starts from
the spherical shell model and is capable of treating an arbitrary linear
combination of multipole and pairing forces. With the restriction of the
interaction to the familiar sum of a quadrupole multipole force and a monopole
pairing force, we have previously studied a semi-microscopic version of the
formalism whose framework is nevertheless more comprehensive than any
previously applied to the problem. We obtained solutions for low-lying bands of
several strongly deformed odd rare earth nuclei and found good agreement with
experiment, except for an exaggerated staggering of levels for K=1/2 bands,
which can be understood as a manifestation of the Coriolis attenuation problem.
We argue that within the formalism utilized, the only way to improve the
physics is to add interactions to the model Hamiltonian. We verify that by
adding a magnetic dipole interaction of essentially fixed strength, we can fit
the K=1/2 bands without destroying the agreement with other bands. In addition
we show that our solution also fits 163Er, a classic test case of Coriolis
attenuation that we had not previously studied.Comment: revtex, including 7 figures(postscript), submitted to Phys.Rev.
Structural and mechanical effects of interstitial sinks Interim technical report, 8 Mar. 1968 - 8 Mar. 1969
Structural and mechanical effects of interstitial sinks in niobium and alloys of niobium and tantalu
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