304 research outputs found
Tverberg-type theorems for intersecting by rays
In this paper we consider some results on intersection between rays and a
given family of convex, compact sets. These results are similar to the center
point theorem, and Tverberg's theorem on partitions of a point set
Psychoanalysis as the Patient: High in Feeling, Low in Energy
This paper examines the increasingly important role that affect is assuming in psychoanalytic research and practice. This rise in the centrality of affect has been at the expense of an independent role for motivation and a dismissal of any energy concept. Difficulties with this affect-first approach are identified and an alternative offered that accords motivation an independent role and accommodates a useful energy concept. Research on esophageal atresia, addiction, and infant suckling are cited in support of this position.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66624/2/10.1177_00030651970450031101.pd
Many-body-QED perturbation theory: Connection to the Bethe-Salpeter equation
The connection between many-body theory (MBPT)--in perturbative and
non-perturbative form--and quantum-electrodynamics (QED) is reviewed for
systems of two fermions in an external field. The treatment is mainly based
upon the recently developed covariant-evolution-operator method for QED
calculations [Lindgren et al. Phys. Rep. 389, 161 (2004)], which has a
structure quite akin to that of many-body perturbation theory. At the same time
this procedure is closely connected to the S-matrix and the Green's-function
formalisms and can therefore serve as a bridge between various approaches. It
is demonstrated that the MBPT-QED scheme, when carried to all orders, leads to
a Schroedinger-like equation, equivalent to the Bethe-Salpeter (BS) equation. A
Bloch equation in commutator form that can be used for an "extended" or
quasi-degenerate model space is derived. It has the same relation to the BS
equation as has the standard Bloch equation to the ordinary Schroedinger
equation and can be used to generate a perturbation expansion compatible with
the BS equation also for a quasi-degenerate model space.Comment: Submitted to Canadian J of Physic
Weakly coupled one-dimensional Mott insulators
We consider a model of one-dimensional Mott insulators coupled by a weak
interchain tunnelling . We first determine the single-particle Green's
function of a single chain by exact field-theoretical methods and then take the
tunnelling into account by means of a Random Phase Approximation (RPA). In
order to embed this approximation into a well-defined expansion with a small
parameter, the Fourier transform of the interchain coupling is
assumed to have a small support in momentum space such that every integration
over transverse wave vector yields a small factor . When
\tp(0) exceeds a critical value, a small Fermi surface develops in the form of
electron and hole pockets. We demonstrate that Luttinger's theorem holds both
in the insulating and in the metallic phases. We find that the quasi-particle
residue increases very fast through the transition and quickly reaches a
value of about . The metallic state close to the transition retains
many features of the one-dimensional system in the form of strong incoherent
continua.Comment: 14 pages, 13 figure
The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour
Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect
The Similarity Hypothesis in General Relativity
Self-similar models are important in general relativity and other fundamental
theories. In this paper we shall discuss the ``similarity hypothesis'', which
asserts that under a variety of physical circumstances solutions of these
theories will naturally evolve to a self-similar form. We will find there is
good evidence for this in the context of both spatially homogenous and
inhomogeneous cosmological models, although in some cases the self-similar
model is only an intermediate attractor. There are also a wide variety of
situations, including critical pheneomena, in which spherically symmetric
models tend towards self-similarity. However, this does not happen in all cases
and it is it is important to understand the prerequisites for the conjecture.Comment: to be submitted to Gen. Rel. Gra
An Examination of Chimpanzee Use in Human Cancer Research
Advocates of chimpanzee research claim the genetic similarity of humans and chimpanzees make them an indispensable research tool to combat human diseases. Given that cancer is a leading cause of human death worldwide, one might expect that if chimpanzees were needed for, or were productive in, cancer research, then they would have been widely used. This comprehensive literature analysis reveals that chimpanzees have scarcely been used in any form of cancer research, and that chimpanzee tumours are extremely rare and biologically different from human cancers. Often, chimpanzee citations described peripheral use of chimpanzee cells and genetic material in predominantly human genomic studies. Papers describing potential new cancer therapies noted significant concerns regarding the chimpanzee model. Other studies described interventions that have not been pursued clinically. Finally, available evidence indicates that chimpanzees are not essential in the development of therapeutic monoclonal antibodies. It would therefore be unscientific to claim that chimpanzees are vital to cancer research. On the contrary, it is reasonable to conclude that cancer research would not suffer, if the use of chimpanzees for this purpose were prohibited in the US. Genetic differences between humans and chimpanzees, make them an unsuitable model for cancer, as well as other human diseases
Culture, Burnout, and Engagement: A Meta-Analysis on National Cultural Values as Moderators in JD-R Theory
Despite prominence and increasing application of the Job DemandsâResources (JDâR) theory across national contexts, the role of culture has not yet been systematically explored. We conducted a metaâanalysis of 132 independent samples from 120 studies across 5 global regions (total N = 101,073) to fill this void. Our paper responds to longâstanding concerns around neglecting differences in the relationships of workplace factors with burnout and engagement across national cultures by testing for a moderating role within JDâR theory. Results suggest strong support for the direct job demandsâburnout and job resourcesâengagement pathways. Regarding the role of culture, our study reveals moderating roles for five out of six cultural dimensions using Hofstedeâs framework. Interestingly, these cultural dimensions present a moderating impact towards relationships with either job demands or job resources, yet not both. Our findings offer a valuable starting point for further theoretical developments that can impact international business and global mobility. While these insights suggest a role of national cultural context in JDâR studies, sensitivity analyses showed that the findings were only partly stable
Brasagem dos aços inoxidåveis duplex 'baixa liga' UNS S32101, UNS S32304 e superduplex UNS S32750 com metal de adição AWS A5.3 tipo BNi-7 (Ni-Cr-P)
Customer emotions in service failure and recovery encounters
Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employeeâcustomer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences
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