1,312 research outputs found
Endocrinological Psychiatry and Psychology
This is the text of a lecture given before the Henry Ford Hospital medical staff by Dr. Bleuer, who is the son of Eugen Bleuler, his predecessor as chairman of psychiatry at the University of Zurich and the man who first named schizophrenia . It is printed here with Dr. Bleuler\u27s permission
Schizophrenia in older adults
Although the number of persons over the age of 55 with schizophrenia is expected to double over the next 20 years, the research data on older people with schizophrenia is limited. This appears to be because until the middle of the 20th century, it was assumed that mental illness in older people was a part of the aging process and older people are often excluded from research investigations. There is a need for nursing research to explore how people with schizophrenia, as they age, learn to manage their problems, as well as how those who are first diagnosed with schizophrenia in later life adapt to their illness. Mental health nurses need to be cautious in assigning premature labels to older adults with mental illness that may lead to unsubstantiated assumptions about levels of disability. Instead, they should realize individual potential regarding undiscovered strengths and should attempt to create interventions that recognize and foster personal development for older adults with schizophrenia
Control of a supernumerary robotic hand by foot: an experimental study in virtual reality.
In the operational theater, the surgical team could highly benefit from a robotic supplementary hand under the surgeon's full control. The surgeon may so become more autonomous; this may reduce communication errors with the assistants and take over difficult tasks such as holding tools without tremor. In this paper, we therefore examine the possibility to control a third robotic hand with one foot's movements. Three experiments in virtual reality were designed to assess the feasibility of this control strategy, the learning curve of the subjects in different tasks and the coordination of foot movements with the two natural hands. Results show that the limbs are moved simultaneously, in parallel rather than serially. Participants' performance improved within a few minutes of practice without any specific difficulty to complete the tasks. Subjective assessment by the subjects indicated that controlling a third hand by foot has been easy and required only negligible physical and mental efforts. The sense of ownership was reported to improve through the experiments. The mental burden was not directly related to the level of motion required by a task, but depended on the type of activity and practice. The most difficult task was moving two hands and foot in opposite directions. These results suggest that a combination of practice and appropriate tasks can enhance the learning process for controlling a robotic hand by foot
In a demanding task, three-handed manipulation is preferred to two-handed manipulation.
Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm
Entanglement from longitudinal and scalar photons
The covariant quantization of the electromagnetic field in the Lorentz gauge
gives rise to longitudinal and scalar photons in addition to the usual
transverse photons. It is shown here that the exchange of longitudinal and
scalar photons can produce entanglement between two distant atoms or harmonic
oscillators. The form of the entangled states produced in this way is very
different from that obtained in the Coulomb gauge, where the longitudinal and
scalar photons do not exist. A generalized gauge transformation is used to show
that all physically observable effects are the same in the two gauges, despite
the differences in the form of the entangled states. An approach of this kind
may be useful for a covariant description of the dynamics of quantum
information processing.Comment: 12 pages, 1 figur
Piecewise Linear Representation Segmentation as a Multiobjective Optimization Problem
Proceedings of: Forth International Workshop on User-Centric Technologies and applications (CONTEXTS 2010). Valencia, September 7-10, 2010Actual time series exhibit huge amounts of data which require an unaffordable computational load to be processed, leading to approximate representations to aid these processes. Segmentation processes deal with this issue dividing time series into a certain number of segments and approximating those segments with a basic function. Among the most extended segmentation approaches, piecewise linear representation is highlighted due to its simplicity. This work presents an approach based on the formalization of the segmentation process as a multiobjetive optimization problem and the resolution of that problem with an evolutionary algorithm.This work was supported in part by Projects CICYT TIN2008-06742-C02-02/TSI, CICYT TEC2008-06732-C02-02/TEC, CAM CONTEXTS (S2009/TIC-1485) and DPS2008-07029-C02-02.Publicad
Pseudo-unitary symmetry and the Gaussian pseudo-unitary ensemble of random matrices
Employing the currently discussed notion of pseudo-Hermiticity, we define a
pseudo-unitary group. Further, we develop a random matrix theory which is
invariant under such a group and call this ensemble of pseudo-Hermitian random
matrices as the pseudo-unitary ensemble. We obtain exact results for the
nearest-neighbour level spacing distribution for (2 X 2) PT-symmetric
Hamiltonian matrices which has a novel form, s log (1/s) near zero spacing.
This shows a level repulsion in marked distinction with an algebraic form in
the Wigner surmise. We believe that this paves way for a description of varied
phenomena in two-dimensional statistical mechanics, quantum chromodynamics, and
so on.Comment: 9 pages, 2 figures, LaTeX, submitted to the Physical Review Letters
on August 20, 200
Solvability and PT-symmetry in a double-well model with point interactions
We show that and how point interactions offer one of the most suitable guides
towards a quantitative analysis of properties of certain specific non-Hermitian
(usually called PT-symmetric) quantum-mechanical systems. A double-well model
is chosen, an easy solvability of which clarifies the mechanisms of the
unavoided level crossing and of the spontaneous PT-symmetry breaking. The
latter phenomenon takes place at a certain natural boundary of the domain of
the "acceptable" parameters of the model. Within this domain the model mediates
a nice and compact explicit illustration of the not entirely standard
probabilistic interpretation of the physical bound states in the very recently
developed (so called PT symmetric or, in an alternative terminology,
pseudo-Hermitian) new, fairly exciting and very quickly developing branch of
Quantum Mechanics.Comment: 24 p., written for the special journal issue "Singular Interactions
in Quantum Mechanics: Solvable Models". Will be also presented to the int.
conference "Pseudo-Hermitian Hamiltonians in Quantum Physics III" (Instanbul,
Koc University, June 20 - 22, 2005)
http://home.ku.edu.tr/~amostafazadeh/workshop/workshop.ht
Gauge equivalence in QCD: the Weyl and Coulomb gauges
The Weyl-gauge ( QCD Hamiltonian is unitarily transformed to a
representation in which it is expressed entirely in terms of gauge-invariant
quark and gluon fields. In a subspace of gauge-invariant states we have
constructed that implement the non-Abelian Gauss's law, this unitarily
transformed Weyl-gauge Hamiltonian can be further transformed and, under
appropriate circumstances, can be identified with the QCD Hamiltonian in the
Coulomb gauge. We demonstrate an isomorphism that materially facilitates the
application of this Hamiltonian to a variety of physical processes, including
the evaluation of -matrix elements. This isomorphism relates the
gauge-invariant representation of the Hamiltonian and the required set of
gauge-invariant states to a Hamiltonian of the same functional form but
dependent on ordinary unconstrained Weyl-gauge fields operating within a space
of ``standard'' perturbative states. The fact that the gauge-invariant
chromoelectric field is not hermitian has important implications for the
functional form of the Hamiltonian finally obtained. When this nonhermiticity
is taken into account, the ``extra'' vertices in Christ and Lee's Coulomb-gauge
Hamiltonian are natural outgrowths of the formalism. When this nonhermiticity
is neglected, the Hamiltonian used in the earlier work of Gribov and others
results.Comment: 25 page
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