457 research outputs found
Archimedes Force on Casimir Apparatus
We address a problem of Casimir apparatus in dense medium and weak
gravitational field. The falling of the apparatus has to be governed by the
equivalence principle, with proper account for contributions to the weight of
the apparatus from its material part and from distorted quantum fields. We
discuss general expression for the corresponding force in metric with
cylindrical symmetry. By way of example we compute explicit expression for
Archimedes force, acting on the Casimir apparatus of finite size, immersed into
thermal bath of free scalar field. It is shown that besides universal term,
proportional to the volume of the apparatus, there are non-universal quantum
corrections, depending on the boundary conditions.Comment: 13 pages, 1 figur
Lattice isomorphisms of bisimple monogenic orthodox semigroups
Using the classification and description of the structure of bisimple
monogenic orthodox semigroups obtained in \cite{key10}, we prove that every
bisimple orthodox semigroup generated by a pair of mutually inverse elements of
infinite order is strongly determined by the lattice of its subsemigroups in
the class of all semigroups. This theorem substantially extends an earlier
result of \cite{key25} stating that the bicyclic semigroup is strongly lattice
determined.Comment: Semigroup Forum (published online: 15 April 2011
Modular and lower-modular elements of lattices of semigroup varieties
The paper contains three main results. First, we show that if a commutative
semigroup variety is a modular element of the lattice Com of all commutative
semigroup varieties then it is either the variety COM of all commutative
semigroups or a nil-variety or the join of a nil-variety with the variety of
semilattices. Second, we prove that if a commutative nil-variety is a modular
element of Com then it may be given within COM by 0-reduced and substitutive
identities only. Third, we completely classify all lower-modular elements of
Com. As a corollary, we prove that an element of Com is modular whenever it is
lower-modular. All these results are precise analogues of results concerning
modular and lower-modular elements of the lattice of all semigroup varieties
obtained earlier by Jezek, McKenzie, Vernikov, and the author. As an
application of a technique developed in this paper, we provide new proofs of
the `prototypes' of the first and the third our results.Comment: 15 page
Howard Shevrin on Peter Wolff
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68168/2/10.1177_00030651990470011701.pd
Generalized Green'S Equivalences on the Subsemigroups of the Bicyclic Monoid
We study generalized Green's equivalences on all subsemigroups of the bicyclic monoid B and determine the abundant (and adequate) subsemigroups of B. © 2010 Copyright Taylor and Francis Group, LLC
Commentaries
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66660/2/10.1177_00030651970450031209.pd
Role-Clarity and Boundaries for Trauma-Informed Teachers
As they begin to implement trauma-informed practices in their classrooms, teachers should consider their role in the lives of students and how to maintain appropriate and safe boundaries with students. This essay explores the role of the teacher in supporting trauma-affected children and offers a frame of teacher as a facilitator of connection. It also offers ways to compassionately maintain boundaries with students while supporting their access to mental health care
Event-related potential indicators of the dynamic unconscious
The present study applies a new method for investigating dynamic unconscious processes. The method consists of (1) selection of words from patient interview and test protocols that in the clinicians' judgments capture the patients' conscious symptom experience (i.e. [phobia) and the hypothetical unconscious conflict related to the symptom, (2) subliminal and supraliminal presentation of these words, (3) signal analysis of event-related potentials (ERPs) obtained to the word presentations. Eight phobics and three patients suffering from pathological grief reactions served as subjects. A time-frequency (Williams & Joeng, 1989) ERP analysis revealed that subjects' ERPs classified the unconscious conflict words better subliminally than supraliminally, while the reverse was true for the conscious symptom words (t(20) = 2.82, P = .011). The relationship between frequency and latency revealed a similar mirror image pattern for the unconscious conflict and conscious symptom words (F(4/36) = 4.14, P = .007). This method demonstrated that objective, brain-based evidence for unconscious conflict can be obtained.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29875/1/0000225.pd
Semigroups with certain finiteness conditions and Chernikov groups
The main purpose of this short survey is to show how groups of special structure, which are accepted to be called Chernikov groups, appeared in the considerations of semigroups with certain finiteness conditions. A structure of groups with several such conditions has been described (they turned out to be special types of Chernikov groups). Lastly, a question concerning some special type of Chernikov groups is recalled; this question was raised by the author more than 35 years ago, and it is still open
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