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Full-Text Articles in Physical Sciences and Mathematics

The Tev Spectrum Of H1426+428, P. T. Reynolds, Et. Al. Nov 2002

The Tev Spectrum Of H1426+428, P. T. Reynolds, Et. Al.

Physical Sciences Publications

The BL Lac object H1426+428 was recently detected as a high-energy γ-ray source by the VERITAS collaboration (Horan et al.). We have reanalyzed the 2001 portion of the data used in the detection in order to examine the spectrum of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with a power law of the shape






The statistical evidence from our data for emission above 2.5 TeV is 2.6 σ. At the 95% confidence level, the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the corresponding flux from the Crab Nebula. The spectrum is …


Discovery Of Spectral Variability Of Markarian 421 At Tev Energies, P. T. Reynolds, Et. Al. Aug 2002

Discovery Of Spectral Variability Of Markarian 421 At Tev Energies, P. T. Reynolds, Et. Al.

Physical Sciences Publications

The detection of spectral variability of the γ-ray blazar Mrk 421 at TeV energies is reported. Observations with the Whipple Observatory 10 m γ-ray telescope taken in 2000/2001 revealed exceptionally strong and long-lasting flaring activity. Flaring levels of 0.4-13 times that of the Crab Nebula flux provided sufficient statistics for a detailed study of the energy spectrum between 380 GeV and 8.2 TeV as a function of the flux level. These spectra are well described by a power law with an exponential cutoff: dN/dE ∝ E-αeimg1.gif m-2 s-1 TeV-1. There is no evidence for variation in the cutoff energy with …


The Evolution Of Cell Colonies In Volvocacean Algae : Investigation By Theoretical Analysis And Computer Simulation., Frank Noe Jan 2002

The Evolution Of Cell Colonies In Volvocacean Algae : Investigation By Theoretical Analysis And Computer Simulation., Frank Noe

Theses

This thesis presents a mathematical analysis and computational simulation which is used to investigate the evolution of cell colonies. The evolutionary transition from unicellular to cell colony form is a prerequesite for multicellular life as it exists abundantly on earth. This transition has occured numerous times independently so that we expect a high selective advantage to be associated with it. The photosynthetic green algae order Volvocaceae is an appropriate set of model organisms for the study of the evolution of cell colonies since it comprises living unicellular organisms, cell colonies, and multicellular organisms of different shapes, sizes and levels of …


The Local Moduli Of Sasakian 3-Manifolds, Brendan Guilfoyle Jan 2002

The Local Moduli Of Sasakian 3-Manifolds, Brendan Guilfoyle

Publications

The Newman-Penrose-Perjes formalism is applied to Sasakian 3-manifolds and the local form of the metric and contact structure is presented. The local moduli space can be parameterised by a single function of two variables and it is shown that, given any smooth function of two variables, there exists locally a Sasakian structure with scalar curvature equal to this function. The case where the scalar curvature is constant (η-Einstein Sasakian metrics) is completely solved locally. The resulting Sasakian manifolds include S 3, Nil, and SL˜ 2 (ℝ), as well as the Berger spheres. It is also shown that a conformally flat …


Closed Industrial Water Cycles, Celine Bellec Jan 2002

Closed Industrial Water Cycles, Celine Bellec

Theses

Due to this decade of rapid growth, Ireland has to face difficulties created by an increase use of water as well as a decreasing water quality due to sewage discharges, agriculture and industries.

The awareness of the danger to the environment, resulting from the over extraction and stricter discharge regulations, has caused the cost of freshwater and wastewater treatment to rise. Therefore there is a growing interest in the manufacturing industries to reduce both freshwater consumption and wastewater production by improving the efficiency of their processes.

Three industrial sectors were studied following the same methodology: the pharmaceutical sector, the textiles …


An Investigation Into The Concepts And Applicability Of Agent Technologies, Anne White Jan 2002

An Investigation Into The Concepts And Applicability Of Agent Technologies, Anne White

Theses

The software world is one of great richness and diversity

Even though the concept of software agents date back to the days of AI (Artificial Intelligence) work (1970’s) the word “Agent” is currently in vogue in the computing press and computer science communities.

This thesis presents a review of the ongoing evolution of software agents, places agents in context within today’s software domain, and takes a closer look at the ongoing debate of what really constitutes an '"Agenf\ The numerous dimensions of classification are studied and an opinion of the attributes that an agent should encompass is put forward. Leading …


Design And Analysis Of Radio Frequency Deployment Algorithms For Gsm, Mónica Pérez-Carbonell Jan 2002

Design And Analysis Of Radio Frequency Deployment Algorithms For Gsm, Mónica Pérez-Carbonell

Theses

Due to the growth of the subscriber base and the introduction of new services, mobile communications networks’ demand for wireless resources is increasing. This has resulted in an increasing need to change the frequency allocation of a network in order to adapt the cellular network to new frequency demands.

Currently, a planning tool generates a new frequency plan, which is. then deployed to cell sites. The deployment should ideally be carried out with minimum disruption to network operation, which makes this deployment process a critical undertaking as any errors during or after the deployment can leave the network with poor …