2,957 research outputs found
Mach's Principle and Model for a Broken Symmetric Theory of Gravity
We investigate spontaneous symmetry breaking in a conformally invariant
gravitational model. In particular, we use a conformally invariant scalar
tensor theory as the vacuum sector of a gravitational model to examine the idea
that gravitational coupling may be the result of a spontaneous symmetry
breaking. In this model matter is taken to be coupled with a metric which is
different but conformally related to the metric appearing explicitly in the
vacuum sector. We show that after the spontaneous symmetry breaking the
resulting theory is consistent with Mach's principle in the sense that inertial
masses of particles have variable configurations in a cosmological context.
Moreover, our analysis allows to construct a mechanism in which the resulting
large vacuum energy density relaxes during evolution of the universe.Comment: 9 pages, no figure
Label-free detection of anticancer drug paclitaxel in living cells by confocal Raman microscopy
Confocal Raman microscopy, a non-invasive, label-free, and high spatial resolution imaging technique is employed to trace the anticancer drug paclitaxel in living Michigan Cancer Foundation-7 (MCF-7) cells. The Raman images were treated by K-mean cluster analysis to detect the drug in cells. Distribution of paclitaxel in cells is verified by calculating the correlation coefficient between the reference spectrum of the drug and the whole Raman image spectra. A time dependent gradual diffusion of paclitaxel all over the cell is observed suggesting a complementary picture of the pharmaceutical action of this drug based on rapid binding of free tubulin to crystallized paclitaxel. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794871
Evaluation of urban infrastructure on the basis of architectural design and landscape ecology
Ideology for landscape Ecology design must be maintained during the design of urban infrastructure and landscape ecology infrastructure can improve the quality of urban environment. Cities and biological complexes are the outcome of human interaction process in various aspects of social, economic, technological, etc., today, with the increasing development of knowledge; the human manipulation in the environment is increasing. And so humans by destroying the natural resources should face several problems, and that’s why different specialties are arise in order to solve the problems. Landscape architecture, including expertise that despite the long history of its use in human life has not much experience in academia environments as an independent field of study. Achievements of this specialty Activities, since it is rooted in nature by enjoying its talent in various aspects such as social issues, ecological and environmental role and could have a strong position for the city dwellers. This article due to needs of ecology design is focused on the effects of infrastructure production in terms of performance, the structure and materials, etc. And creating reasonable rules for ecological planning and landscape architecture in order to establish the foundations for the future development of ecology design methods for infrastructure.Keywords: landscape architecture; ecology; urban infrastructure
CPOE in Iran-A viable prospect?. Physicians' opinions on using CPOE in an Iranian teaching hospital
Background: In recent years, the theory that on-line clinical decision support systems can improve patients' safety among hospitalised individuals has gained greater acceptance. However, the feasibility of implementing such a system in a middle or low-income country has rarely been studied. Understanding the current prescription process and a proper needs assessment of prescribers can act as the key to successful implementation. Objectives: The aim of this study was to explore physicians' opinions on the current prescription process, and the expected benefits and perceived obstacles to employ Computerised Physician Order Entry in an Iranian teaching hospital. Methods: Initially, the interview guideline was developed through focus group discussions with eight experts. Then semi-structured interviews were held with 19 prescribers. After verbatim transcription, inductive thematic analysis was performed on empirical data. Forty hours of on-looker observations were performed in different wards to explore the current prescription process. Results: The current prescription process was identified as a physician-centred, top-down, model, where prescribers were found to mostly rely on their memories as well as being overconfident. Some errors may occur during different paper-based registrations, transcriptions and transfers. Physician opinions on Computerised Physician Order Entry were categorised into expected benefits and perceived obstacles. Confidentiality issues, reduction of medication errors and educational benefits were identified as three themes in the expected benefits category. High cost, social and cultural barriers, data entry time and problems with technical support emerged as four themes in the perceived obstacles category. Conclusions: The current prescription process has a high possibility of medication errors. Although there are different barriers confronting the implementation and continuation of Computerised Physician Order Entry in Iranian hospitals, physicians have a willingness to use them if these systems provide significant benefits. A pilot study in a limited setting and a comprehensive analysis of health outcomes and economic indicators should be performed, to assess the merits of introducing Computerised Physician Order Entry with decision support capabilities in Iran. © 2008 Elsevier Ireland Ltd. All rights reserved
Clearing algorithms and network centrality
I show that the solution of a standard clearing model commonly used in
contagion analyses for financial systems can be expressed as a specific form of
a generalized Katz centrality measure under conditions that correspond to a
system-wide shock. This result provides a formal explanation for earlier
empirical results which showed that Katz-type centrality measures are closely
related to contagiousness. It also allows assessing the assumptions that one is
making when using such centrality measures as systemic risk indicators. I
conclude that these assumptions should be considered too strong and that, from
a theoretical perspective, clearing models should be given preference over
centrality measures in systemic risk analyses
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