2,473 research outputs found
Observation of Interaction of Spin and Intrinsic Orbital Angular Momentum of Light
Interaction of spin and intrinsic orbital angular momentum of light is
observed, as evidenced by length-dependent rotations of both spatial patterns
and optical polarization in a cylindrically-symmetric isotropic optical fiber.
Such rotations occur in straight few-mode fiber when superpositions of two
modes with parallel and anti-parallel orientation of spin and intrinsic orbital
angular momentum (IOAM=) are excited, resulting from a degeneracy
splitting of the propagation constants of the modes.Comment: 6 pages, 5 figures, and a detailed supplement. Version 3 corrects a
typo and adds the journal referenc
Epidemiology of Lead Poisoning in Cattle
The case histories of lead poisoning diagnosed in 63 herds of cattle over the past five years were studied. The toxicosis was found to be most prominent during the spring months and resulted in a 61 percent fatality rate. The clinical signs observed involved mainly the central nervous and gastrointestinal systems, as did the post mortem findings. The mean tissue lead levels were determined and correlated with the source of the toxicant
Stable Mode Sorting by Two-Dimensional Parity of Photonic Transverse Spatial States
We describe a mode sorter for two-dimensional parity of transverse spatial
states of light based on an out-of-plane Sagnac interferometer. Both
Hermite-Gauss (HG) and Laguerre-Gauss (LG) modes can be guided into one of two
output ports according to the two-dimensional parity of the mode in question.
Our interferometer sorts HG_nm input modes depending upon whether they have
even or odd order n+m; it equivalently sorts LG modes depending upon whether
they have an even or odd value of their orbital angular momentum. It functions
efficiently at the single-photon level, and therefore can be used to sort
single-photon states. Due to the inherent phase stability of this type of
interferometer as compared to those of the Mach-Zehnder type, it provides a
promising tool for the manipulation and filtering of higher order transverse
spatial modes for the purposes of quantum information processing. For example,
several similar Sagnacs cascaded together may allow, for the first time, a
stable measurement of the orbital angular momentum of a true single-photon
state. Furthermore, as an alternative to well-known holographic techniques, one
can use the Sagnac in conjunction with a multi-mode fiber as a spatial mode
filter, which can be used to produce spatial-mode entangled Bell states and
heralded single photons in arbitrary first-order (n+m=1) spatial states,
covering the entire Poincare sphere of first-order transverse modes.Comment: 11 pages, 12 figures, 2 appendice
Unequal relationships in high and low power distance societies: a comparative study of tutor - student role relations in Britain and China
This study investigated people's conceptions of an unequal role relationship in two different types of society: a high power distance society and a low power distance society. The study focuses on the role relationship of tutor and student. British and Chinese tutors and postgraduate students completed a questionnaire that probed their conceptions of degrees of power differential and social distance/closeness in this role relationship. ANOVA results yielded a significant nationality effect for both aspects. Chinese respondents judged the relationship to be closer and to have a greater power differential than did British respondents. Written comments on the questionnaire and interviews with 9 Chinese academics who had experienced both British and Chinese academic environments supported the statistical findings and indicated that there are fundamental ideological differences associated with the differing conceptions. The results are discussed in relation to Western and Asian concepts of leadership and differing perspectives on the compatibility/incompatibility of power and distance/closeness
Unbiased Global Optimization of Lennard-Jones Clusters for N <= 201 by Conformational Space Annealing Method
We apply the conformational space annealing (CSA) method to the Lennard-Jones
clusters and find all known lowest energy configurations up to 201 atoms,
without using extra information of the problem such as the structures of the
known global energy minima. In addition, the robustness of the algorithm with
respect to the randomness of initial conditions of the problem is demonstrated
by ten successful independent runs up to 183 atoms. Our results indicate that
the CSA method is a general and yet efficient global optimization algorithm
applicable to many systems.Comment: revtex, 4 pages, 2 figures. Physical Review Letters, in pres
The Experiences of Specialist Nurses Working Within the Uro-oncology Multidisciplinary Team in the United Kingdom.
PURPOSE: United Kingdom prostate cancer nursing care is provided by a variety of urology and uro-oncology nurses. The experience of working in multidisciplinary teams (MDT) was investigated in a national study. DESIGN: The study consisted of a national survey with descriptive statistics and thematic analysis. METHODS: A secondary analysis of a data subset from a UK whole population survey was undertaken (n = 285) of the specialist nursing workforce and the services they provide. Data were collected on the experience of working in the MDT. RESULTS: Forty-five percent of the respondents felt that they worked in a functional MDT, 12% felt that they worked in a dysfunctional MDT, and 3.5% found the MDT meeting intimidating. Furthermore, 34% of the nurses felt that they could constructively challenge all members of the MDT in meetings. Themes emerging from open-ended questions were lack of interest in nonmedical concerns by other team members, ability to constructively challenge decisions or views within the meeting, and little opportunity for patients' wishes to be expressed. CONCLUSIONS: Despite expertise and experience, nurses had a variable, often negative, experience of the MDT. It is necessary to ensure that all participants can contribute and are heard and valued. More emphasis should be given to patients' nonmedical needs
Follow-up imaging of benign pediatric liver tumors
Though surgery has been recommended in the past for the management of benign hepatic tumors, the current emphasis is on medical management. This report of 4 cases with long-term (8–28 months) follow-up emphasizes the natural history of these tumors which serves to indicate the advantages and disadvantages of CT and ultrasound. The lesions typically involute with some calcification. Calcification can technically be a problem in follow-up with sonography.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46688/1/247_2006_Article_BF02386841.pd
New Tetrahedral Global Minimum for the 98-atom Lennard-Jones Cluster
A new atomic cluster structure corresponding to the global minimum of the
98-atom Lennard-Jones cluster has been found using a variant of the
basin-hopping global optimization algorithm. The new structure has an unusual
tetrahedral symmetry with an energy of -543.665361, which is 0.022404 lower
than the previous putative global minimum. The new LJ_98 structure is of
particular interest because its tetrahedral symmetry establishes it as one of
only three types of exceptions to the general pattern of icosahedral structural
motifs for optimal LJ microclusters. Similar to the other exceptions the global
minimum is difficult to find because it is at the bottom of a narrow funnel
which only becomes thermodynamically most stable at low temperature.Comment: 3 pages, 2 figures, revte
Computational and Biological Analogies for Understanding Fine-Tuned Parameters in Physics
In this philosophical paper, we explore computational and biological
analogies to address the fine-tuning problem in cosmology. We first clarify
what it means for physical constants or initial conditions to be fine-tuned. We
review important distinctions such as the dimensionless and dimensional
physical constants, and the classification of constants proposed by
Levy-Leblond. Then we explore how two great analogies, computational and
biological, can give new insights into our problem. This paper includes a
preliminary study to examine the two analogies. Importantly, analogies are both
useful and fundamental cognitive tools, but can also be misused or
misinterpreted. The idea that our universe might be modelled as a computational
entity is analysed, and we discuss the distinction between physical laws and
initial conditions using algorithmic information theory. Smolin introduced the
theory of "Cosmological Natural Selection" with a biological analogy in mind.
We examine an extension of this analogy involving intelligent life. We discuss
if and how this extension could be legitimated.
Keywords: origin of the universe, fine-tuning, physical constants, initial
conditions, computational universe, biological universe, role of intelligent
life, cosmological natural selection, cosmological artificial selection,
artificial cosmogenesis.Comment: 25 pages, Foundations of Science, in pres
Parental bonding and identity style as correlates of self-esteem among adult adoptees and nonadoptees
Adult adoptees (n equals 100) and non-adoptees (n equals 100) were compared with regard to selfesteem, identity processing style, and parental bonding. While some differences were found with regard to self-esteem, maternal care, and maternal overprotection, these differences were
qualified by reunion status such that only reunited adoptees differed significantly from nonadoptees.
Moreover, hierarchical regression analyses indicated that parental bonding and identity processing style were more important than adoptive status per se in predicting self esteem. Implications for practitioners who work with adoptees are discussed
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