3,468 research outputs found
Persona in Poetry
Persona in poetry has for ages been used to convey character, as in the poetry of John Milton and T. S. Eliot. Personas may be used to construct a character, or deliver the voice of a cultural, historical, or literary figure. This key technique is important in the understanding of literature
Thyrotoxicosis-facilitated bridge to recovery with a continuous-flow left ventricular assist device
The HeartMate II is a continuous-flow left ventricular assist device that can be explanted from patients after cardiac recovery. We implanted a HeartMate II in a 21-year-old man who had idiopathic cardiomyopathy. A year later, he developed thyrotoxicosis, presumably secondary to amiodarone administered for ventricular fibrillation. Four months after the diagnosis of thyrotoxicosis, thyroid hormone levels had returned to normal, and native cardiac function had improved remarkably. After a support period of 24 months, the HeartMate II was explanted. Six years later, the patient continues to be in New York Heart Association functional Class I. Amiodarone-induced thyrotoxicosis may have contributed to myocardial recover
Concerns of Custom Harvesters
This study elicited the perceptions and concerns of custom harvesters regarding safety and health issues faced in their operations, self‐perceived knowledge of selected regulations, and self‐perceived ability to train employees on the safe operation of equipment. The average age of custom harvesters\u27 (CH) employees was 22 to 25 years (47.2%). The most common length of the harvest season was 5 to 6 months (70.9%). The most common responses to length of work day were 9 to 11 hours (34.5%) and 12 to 14 hours (54.5%). In general, CH ranked combine operation experience as most important when hiring employees. The CH felt inexperience was the leading contributor to lost‐time incidents. They were most concerned about DOT regulations and Worker\u27s Compensation rules, but also felt they had a good knowledge of those areas
Unconventional decay law for excited states in closed many-body systems
We study the time evolution of an initially excited many-body state in a
finite system of interacting Fermi-particles in the situation when the
interaction gives rise to the ``chaotic'' structure of compound states. This
situation is generic for highly excited many-particle states in quantum
systems, such as heavy nuclei, complex atoms, quantum dots, spin systems, and
quantum computers. For a strong interaction the leading term for the return
probability has the form with
as the variance of the strength function. The conventional
exponential linear dependence formally arises for a
very large time. However, the prefactor turns out to be exponentially
large, thus resulting in a strong difference from the conventional estimate for
.Comment: RevTex, 4 pages including 1 eps-figur
Chaotic wave functions and exponential convergence of low-lying energy eigenvalues
We suggest that low-lying eigenvalues of realistic quantum many-body
hamiltonians, given, as in the nuclear shell model, by large matrices, can be
calculated, instead of the full diagonalization, by the diagonalization of
small truncated matrices with the exponential extrapolation of the results. We
show numerical data confirming this conjecture. We argue that the exponential
convergence in an appropriate basis may be a generic feature of complicated
("chaotic") systems where the wave functions are localized in this basis.Comment: 4 figure
Entropy production and wave packet dynamics in the Fock space of closed chaotic many-body systems
Highly excited many-particle states in quantum systems such as nuclei, atoms,
quantum dots, spin systems, quantum computers etc., can be considered as
``chaotic'' superpositions of mean-field basis states (Slater determinants,
products of spin or qubit states). This is due to a very high level density of
many-body states that are easily mixed by a residual interaction between
particles (quasi-particles). For such systems, we have derived simple
analytical expressions for the time dependence of energy width of wave packets,
as well as for the entropy, number of principal basis components and inverse
participation ratio, and tested them in numerical experiments. It is shown that
the energy width increases linearly and very quickly saturates.
The entropy of a system increases quadratically, at small
times, and after, can grow linearly, , before the saturation.
Correspondingly, the number of principal components determined by the entropy,
, or by the inverse participation ratio, increases
exponentially fast before the saturation. These results are explained in terms
of a cascade model which describes the flow of excitation in the Fock space of
basis components. Finally, a striking phenomenon of damped oscillations in the
Fock space at the transition to an equilibrium is discussed.Comment: RevTex, 14 pages including 12 eps-figure
Multiscale fluctuations in nuclear response
The nuclear collective response is investigated in the framework of a doorway
picture in which the spreading width of the collective motion is described as a
coupling to more and more complex configurations. It is shown that this
coupling induces fluctuations of the observed strength. In the case of a
hierarchy of overlapping decay channels, we observe Ericson fluctuations at
different scales. Methods for extracting these scales and the related lifetimes
are discussed. Finally, we show that the coupling of different states at one
level of complexity to some common decay channels at the next level, may
produce interference-like patterns in the nuclear response. This quantum effect
leads to a new type of fluctuations with a typical width related to the level
spacing.Comment: 34 Latex pages including 6 figures (submitted to Phys. Rev. C
Reading sentences with a late closure ambiguity: does semantic information help?
Stowe (1989) reported that semantic information eliminates garden paths in sentences with the direct-object vs. subject ambiguity, such as Even before the police stopped the driver was very frightened. Three experiments are presented which addressed some methodological problems in Stowe's study. Experiment 1, using a word-by-word, self-paced reading task with grammaticality judgements, manipulated animacy of the first subject noun while controlling for the plausibility of the transitive action. The results suggest that initial sentence analysis is not guided by animacy. Experiment 2 and 3, using the self-paced task with grammaticality judgements and eye-tracking, varied the plausibility of the direct-object nouns to test revision effects. Plausibility was found to facilitate revision without fully eliminating garden paths, in line with various revision models. The findings support the view of a sentence processing system relying heavily on syntactic information, with semantic information playing a weaker role both in initial analysis and during revision, thus supporting serial, syntax-first models and ranked-parallel models relying on structural criteria
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