Covariant Irreducible Parametrization of Electromagnetic Fields in Arbitrary Spacetime

We present a new unified covariant description of electromagnetic field properties for an arbitrary space-time. We derive a complete set of irreducible components describing a six-dimensional electromagnetic field from the Maxwell and metric tensors using the symmetry group SL(2,C). For the special case of a flat space-time metric the components are shown to correspond to the scalar invariants of the electromagnetic field, the energy-momentum-stress tensor and in addition, three new tensors expressing physical observables of rank two and four, respectively. We make a physical interpretation of one of the new rank two tensors as describing a classical intrinsic spin of the electromagnetic field.Comment: 11 pages, no figures, Will appear in J. Math. Phys., January (2006

Navigating multiple sites: religion and women\u27s NGO activism in Cairo

In this project, I explore and problematize the demarcation of religious versus secular based women\u27s activism in Egypt. In doing so, this thesis accompanies the body of literature that contests liberal feminists\u27 assumptions that Islam and gender justice are incompatible and that Muslim women\u27s lives are linked to religious and cultural factors only. Through fieldwork at the Cariene women\u27s NGO, Center for Egyptian Women\u27s Legal Assistance (CEWLA), this thesis reveals that women\u27s rights work can operate within frameworks, which are rooted simultaneously in liberal secular ideas, and Islamic discourses of gender justice. CEWLA is an organization that aims to establish equity among citizens and runs myriads of right based- and development driven projects. The center bases its mission and objectives on the international human rights conventions of which CEDAW is a significant reference. However, the organization systematically engages Islamic discourse throughout their work. The deployment of religion encourages dialogue and provides a space where discourses of women\u27s rights work, gender justice, and Islam can convene and be debated. This thesis argues that the members of CEWLA navigate among the multiple discourses at play in women\u27s right work and the Egyptian society. Since religion is a vital discourse on which people\u27s social imagination is structured, it becomes axiomatic for CEWLA members to deploy religious knowledge. Through analyzing how CEWLA recognizes the complex and non-clear cut religious and secular dimensions in Egypt, I locate the deployment of religious discourse within the wider debate on women\u27s right work and gender justice in an era of transnational feminism

Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind

The proton temperature anisotropy in the solar wind is known to be constrained by the theoretical thresholds for pressure anisotropy-driven instabilities. Here we use approximately 1 million independent measurements of gyroscale magnetic fluctuations in the solar wind to show for the first time that these fluctuations are enhanced along the temperature anisotropy thresholds of the mirror, proton oblique firehose, and ion cyclotron instabilities. In addition, the measured magnetic compressibility is enhanced at high plasma beta ($\beta_\parallel \gtrsim 1$) along the mirror instability threshold but small elsewhere, consistent with expectations of the mirror mode. The power in this frequency (the 'dissipation') range is often considered to be driven by the solar wind turbulent cascade, an interpretation which should be qualified in light of the present results. In particular, we show that the short wavelength magnetic fluctuation power is a strong function of collisionality, which relaxes the temperature anisotropy away from the instability conditions and reduces correspondingly the fluctuation power.Comment: 4 pages, 4 figure

A model for linking shop floor improvements to manufacturing cost and profitability

Manufacturing units in the so called high-cost countries are struggling under fierce competition on the global market. In order to survive, the factory needs to generate profit to its owners. Profitability can be reached in many different ways apart from only lowering the employees' salaries. It can be improved through increased profit margins (sales in relation to costs) or with an increased capital turnover rate. Finding ways to free capacity and to improve flexibility in order to increase sales is often more interesting to the manufacturing companies than cutting the direct salary costs. A model for analysing profitability of a manufacturing unit is proposed. It is found on a production system analysis and combines in-depth production engineering analysis with economical accounting analysis of the factory. The manual work tasks are of special interest and the productivity of selected bottleneck work areas are analysed thoroughly. The model is intended for use by two industrial analysts during a one-week study. Simulation of different improvement scenarios is carried out and presented to the factory management at the end of the profitability study. A software implementation is required in order to generate the model, collect data and make simulation within the intended time. The implementation is made in spread sheet software using Visual Basic to program interfaces and automatic functions. The primary area of application is the electronics industry in Sweden where the model is used in a research project to strengthen the competitiveness of that industry

Subclinical sympathetic neuropathy appears early in the course of Crohn's disease

<p>Abstract</p> <p>Background</p> <p>We have previously demonstrated that patients with Crohn's disease (CD) of long duration have signs of autonomic neuropathy. The aim of this study was to examine whether autonomic neuropathy is an early manifestation of CD, or a sign appearing late in the course.</p> <p>Methods</p> <p>Twenty patients, median age 40 years, with a short duration of CD were included. Examination of autonomic reflexes included heart rate reaction to tilt (acceleration index – AI, brake index – BI) and heart rate variation to deep-breathing (expiration/inspiration index-E/I). Seven years later the same examinations were repeated, and in addition we examined the vasoconstriction response to indirect cooling by laser Doppler (vasoconstriction-index – VAC-index). The results were compared with healthy individuals.</p> <p>Results</p> <p>There was no difference in the blood pressure between controls and the patients with CD at rest, but eight minutes after tilt, the systolic blood pressure was lowered in patients compared to controls, both at the first assessment (p = 0.016) and after seven years (p = 0.042). The change in systolic blood pressure between rest and eight minutes after tilt was not significant at the first assessment, while a significant change compared to controls was observed seven years later (p = 0.028). This indicates a progressive dysfunction. There were no differences in E/I, AI, BI or VAC indexes between patients and controls.</p> <p>Conclusion</p> <p>Patients with CD suffer from autonomic neuropathy early in their disease, suggesting involvement of many different organ systems in this entity.</p

Object-oriented Modeling of Manufacturing Resources Using Work Study Inputs

Resources are the core of manufacturing models. They provide information about the people and equipment that perform activities on the shop floor. Comprehensive representations of equipment are common but human resources are often defined to a very limited extent. This paper presents how work study data can be applied as input to detailed modeling of human manufacturing resources. The purpose is to provide a valid representation of manual work tasks on a shop floor level. If implemented in manufacturing models the valid representation will contribute to improve planning, control and execution of production. It also facilitates and encourages production improvement initiatives