| 1. |
- Ambrosio, M, et al.
(author)
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Final results of magnetic monopole searches with the MACRO experiment
- 2002
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In: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 25:4, s. 511-522
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Journal article (peer-reviewed)abstract
- We present the final results obtained by the MACRO experiment in the search for GUT magnetic monopoles in the penetrating cosmic radiation, for the range 4 x 10(-5) < 3 < 1. Several searches with all the MACRO sub-detectors (i.e. scintillation counters, limited streamer tubes and nuclear track detectors) were performed, both in stand alone and combined ways. No candidates were detected and a 90% Confidence Level (C.L.) upper limit to the local magnetic monopole flux was set at the level of 1.4 x 10(-16) cm(-2) s(-1) sr(-1). This result is the first experimental limit obtained in direct searches which is well below the Parker bound in the whole 3 range in which GUT magnetic monopoles are,expected.
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| 2. |
- Togo, V, et al.
(author)
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Calibrations of CR39 and Makrofol nuclear track detectors and search for exotic particles
- 2003
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In: Nuclear physics B, Proceedings supplements. - : Elsevier. - 0920-5632 .- 1873-3832. ; 125, s. 217-221
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Journal article (peer-reviewed)abstract
- We present the final results of the search for exotic massive particles in the cosmic radiation performed with the MACRO underground experiment. Magnetic monopoles and nuclearites flux upper limits obtained with the CR39 nuclear track subdetector, the scintillation and streamer tube subdetectors are given. Searches at high altitude with the SLIM experiment are in progress.
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| 3. |
- Alcorn, J, et al.
(author)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Journal article (peer-reviewed)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 4. |
- Ambrosio, M, et al.
(author)
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Atmospheric neutrino oscillations from upward throughgoing muon multiple scattering in MACRO
- 2003
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In: Physics Letters B. - 0370-2693 .- 1873-2445. ; 566:1-2, s. 35-44
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Journal article (peer-reviewed)abstract
- The energy of atmospheric neutrinos detected by MACRO was estimated using multiple Coulomb scattering of upward throughgoing muons. This analysis allows a test of atmospheric neutrino oscillations, relying on the distortion of the muon energy distribution. These results have been combined with those coming from the upward throughgoing muon angular distribution only. Both analyses are independent of the neutrino flux normalization and provide strong evidence, above the for level, in favour of neutrino oscillations. (C) 2003 Published by Elsevier B.V.
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| 5. |
- Ambrosio, M, et al.
(author)
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Moon and Sun shadowing effect in the MACRO detector
- 2003
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In: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 20:2, s. 145-156
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Journal article (peer-reviewed)abstract
- Using data collected by the MACRO experiment from 1989 to the end of its operations in 2000, we have studied in the underground muon flux the shadowing. effects due to both the Moon and the Sun. We have observed the shadow cast by the Moon at its apparent position with a significance of 6.5sigma. The Moon shadowing effect has been used to verify the pointing capability of the detector and to determine the instrument resolution for the search of muon excesses from any direction of the celestial sphere. The dependence of the effect on the geomagnetic field is clearly shown by splitting the data sample in day and night observations. The Sun shadow, observed with a significance of 4.6sigma is displaced by about 0.6degrees from its apparent position. In this case however the explanation resides in the configuration of the Solar and Interplanetary Magnetic Fields, which affect the propagation of cosmic ray particles between the Sun, and the Earth. The displacement of the Sun shadow with respect to the real Sun position has been used to establish an upper limit on the antimatter flux in cosmic rays of about 48% at 68% c.l. and primary energies of about 20 TeV. (C) 2003 Elsevier B.V. All rights reserved.
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| 6. |
- Popat, S, et al.
(author)
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Variation in the CTLA4/CD28 gene region confers an increased risk of coeliac disease.
- 2002
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In: Annals of human genetics. - 0003-4800 .- 1469-1809. ; 66:Pt 2, s. 125-37
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Journal article (peer-reviewed)abstract
- Susceptibility to coeliac disease involves HLA and non-HLA-linked genes. The CTLA4/CD28 gene region encodes immune regulatory T-cell surface molecules and is a strong candidate as a susceptibility locus. We evaluated CTLA4/CD28 in coeliac disease by genetic linkage and association and combined our findings with published studies through a meta-analysis. 116 multiplex families were genotyped across CTLA4/CD28 using eight markers. The contribution of CTLA4/CD28 to coeliac disease was assessed by non-parametric linkage and association analyses. Seven studies were identified that had evaluated the relationship between CTLA4/CD28 and coeliac disease and a pooled analysis of data undertaken. In our study there was evidence for a relationship between variation in the CTLA4/CD28 region and coeliac disease by linkage and association analyses. However, the findings did not attain formal statistical significance (p = 0.004 and 0.039, respectively). Pooling findings with published results showed significant evidence for linkage (504 families) and association (940 families): p values, 0.0001 and 0.0014 at D2S2214, respectively, and 0.0008 and 0.0006 at D2S116, respectively. These findings suggest that variation in the CD28/CTLA4 gene region is a determinant of coeliac disease susceptibility. Dissecting the sequence variation underlying this relationship will depend on further analyses utilising denser sets of markers.
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| 7. |
- Popat, S, et al.
(author)
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Genome screening of coeliac disease
- 2002
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In: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 39:5, s. 328-331
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Journal article (peer-reviewed)
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Simpson, P. J., et al.
(author)
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Observation of fluorine-vacancy complexes in silicon
- 2004
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85:9, s. 1538-
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Journal article (peer-reviewed)abstract
- We show direct evidence, obtained by positron annihilation spectroscopy, for the complexing of fluorine with vacancies in silicon. Both float zone and Czochralski silicon wafers were implanted with 30 keV fluorine ions to a fluence of 2×1014 ions/cm2, and studied in the as-implanted condition, and after annealing to 650 °C for 10 and for 30 min. The "2-detector" background reduction technique for positron annihilation was applied. The spectra reveal a significant concentration of fluorine-vacancy complexes after annealing, for both Czochralski and float zone material, supporting the results of computer simulations of the implantation and annealing process.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Arul, A.J., et al.
(author)
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The power law character of off-site power failures
- 2003
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In: Annals of Nuclear Energy. - 0306-4549. ; 30:14, s. 1401-1408
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Journal article (peer-reviewed)abstract
- A study on the behavior of off-site AC power failure recovery times at three nuclear plant sites is presented. It is shown, that power law is appropriate for the representation of failure frequency–duration correlation function of off-site power failure events, based on simple assumptions about component failure and repair rates. It is also found that the annual maxima of power failure duration follow Frechet distribution, which is a type II asymptotic distribution, strengthening our assumption of power law for the parent distribution. The extreme value distributions obtained are used for extrapolation beyond the region of observation.
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| 17. |
- Badel, Xavier, et al.
(author)
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Formation of ordered pore arrays at the nanoscale by electrochemical etching of n-type silicon
- 2004
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In: Superlattices and Microstructures. - : Elsevier BV. - 0749-6036 .- 1096-3677. ; 36:1/3, s. 245-254
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Journal article (peer-reviewed)abstract
- Electrochemical etching has been studied to structure n-type silicon substrates at the nanoscale. In this work, well-ordered pore arrays with diameters in the range of 150-500 nm and depths up to 50 mum have been fabricated. The pores were successfully formed by anodic etching in (100)oriented n-type silicon wafers of low-resistivity, typically 1 Omegacm, using aqueous hydrofluoric acid solutions. The lithographic step was performed in a thermally grown oxide using a stepper and dry oxide etching technique. Two types of oxide openings and pitch sizes were tested. The smallest oxide opening realised at this stage was 0.5 mum for a pitch of 1 mum. Stable pore formation was obtained and the smallest pore size obtained was about 200 nm with an aspect ratio close to 100.
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| 18. |
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| 19. |
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| 20. |
- Jacobsohn, L. G, et al.
(author)
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Role of intericosahedral chains on hardness of sputtered boron carbide films
- 2004
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 84:21, s. 4173-
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Journal article (peer-reviewed)abstract
- The relationship between the structure and mechanical properties of sputter-deposited boron carbide films was investigated. Changes in the structure induced by annealing were characterized in terms of chemical composition, chemical bonding, and concentrations of defects and trapped impurities. The creation of intericosahedral chains for higher annealing temperatures was revealed by infrared and Raman measurements, and the intensity of the infrared band at 1500 cm–1 was found to be related to the hardness. The presence of residual trapped Ar atoms and of open-volume defects is insensitive to relatively high annealing temperatures and does not influence the recovery of the hardness. Our results suggest postdeposition annealing as a pathway to enhance the mechanical properties of boron carbide films.
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| 21. |
- Jantsch, A, et al.
(author)
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Comparison of Six Languages for System Level Descriptions of Telecom Systems
- 2001
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In: Electronic Chips & Systems Design Languages. - Boston, Mass. : Kluwer Academic Publishers. - 0792373111 ; , s. 320-
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Book chapter (other academic/artistic)abstract
- Language evaluation for various purposes is an often repeated exercise in industry and academia. Due to the large number of influencing factors the dependence of the result on implicit or explicit assumptions is not always apparent and clear. Based on a systematic evaluation method with a large number of criteria we compare six languages with respect to the suitability as a system specification and description language for telecom applications. The languages under evaluation are VHDL, C++, SDL, Haskell, Erlang, and ProGram, which represent different paradigms. The evaluation method allows to give specific emphasis on particular aspects in a controlled way, which we use to make separate comparisons for pure software systems, pure hardware systems and mixed HW/SW systems.
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| 22. |
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| 23. |
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| 24. |
- Kumar, Sunil J., et al.
(author)
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A simple method for synthesis of organotin species to investigate extraction procedures in sediments by isotope dilution-gas chromatography-inductively coupled plasma mass spectrometry : Part 2. Phenyltin species
- 2004
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In: Journal of Analytical Atomic Spectrometry. - London : Royal Society of Chemistry. - 0267-9477 .- 1364-5544. ; 19:3, s. 368-372
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Journal article (peer-reviewed)abstract
- A rapid method for the synthesis of phenyltin species based on the phenylation of tin iodide was developed and a standard of 124Sn, enriched monophenyltin (MPhT), diphenyltin (DPhT) and triphenyltin (TPhT) was produced. Isotope enriched species were added to and equilibrated with the certified reference material BCR 646 to evaluate different extraction procedures currently in use for the determination of organic tin species in sediments. Samples were measured by gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS) with species specific isotope dilution (SSID) calibration. For TPhT measurement results agreed with the certified values for extraction methods using tropolone in diethyl ether alone or in the presence of NaCl and HCl as well as with 50% HBr. However, with 50% HBr, concentrations obtained for DPhT and MPhT were above the upper limit (2) of the certification. The stability of phenyltin species was studied by comparing their signal magnitudes in spike solutions generated directly after derivatisation with those obtained after applying the extraction–derivatisation procedures. Degradation of phenyltin species was matrix dependent and appeared for most of the extraction methods investigated. For water standards and BCR 646, extraction with methanol combined with dichloromethane or methanol combined with acetic acid gave no degradation when applied with less than 20 min ultrasonication. Extraction efficiencies for these two methods were however low for the BCR 646 matrix, in particular for DPhT and MPhT.
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| 25. |
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| 26. |
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| 27. |
- Liyanage, Jayantha P., et al.
(author)
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A global framework to manage operations & maintenance(O&M) performance to condition plant health: Reflections from the norwegian oil & gas industry
- 2004
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In: International Journal of COMADEM. - 1363-7681. ; 7:1, s. 39-44
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Journal article (peer-reviewed)abstract
- Effective management of operations and maintenance performance has a significant impact on the management of oil and gas production assets. Apparently, its organization wide implications are much wider in reality than in classical cost centered views in the current oil and gas business environment. Oil and gas producers today are much keen on understanding the business impact of operations and maintenance process, but seemingly the underlying subject matter has not been fully explored and understood yet. In this paper we attempt to shed some light in this endeavor by exploring the significance of operations and maintenance performance in the current oil and gas business environment from a different viewpoint. Here we advocate that to meaningfully illustrate how operations and maintenance performance makes good business sense, the ideal point of departure is the overall value proposition of the business. Accordingly, we, elaborate how this value proposition should be brought into perspectives within production asset and operations and maintenance performance. The underlying aim is to develop a priori performance model that in turn lead to development of performance assessment systems. Elaborations in this paper are based on our observations, learning and experience within the Norwegian petroleum industry.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
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| 33. |
- Liyanage, Jayantha P., et al.
(author)
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Process of maintenance performance management and its imperatives within the offshore petroleum industry : Part II: The principles of value based maintenance performance management
- 2002
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In: SMRP Solutions. - 1552-5082. ; :2
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Journal article (other academic/artistic)abstract
- In Part I we addressed the emerging environment for asset maintenance in terms of business prosperity and plant economics. In this series of articles we advocate that the starting point for any measurement system,in the current business environment, is the need to move away from the classical cost and profit perspective to a more value-based perspective. Accordingly, in this paper, we discuss the principles of our new concept termed "value based maintenance performance management." This intends to be a thought-provoking new concept to substantiate development of operations and maintenance performance indicators for industrial asset maintenance. This is in line with an on-going joint industry project on development and implementation of maintenance performance indicators for the petroleum industry in Norway.
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| 34. |
- Liyanage, Jayantha P., et al.
(author)
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Process of maintenance performance management and its imperatives within the offshore petroleum industry : Part III: Integration of maintenance performance to corporate value process
- 2002
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In: SMRP Solutions. - 1552-5082. ; :3
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Journal article (other academic/artistic)abstract
- The following is a continuation of our series addressing the principles of a new concept termed Value-based maintenance performance management.We advocate that the starting point for any measurement system,in the current business environment, is the need to move away from a classical cost and profit perspective to a more value-based perspective. In this paper, we discuss the integration of maintenance as a value delivery process rather than a cost center.This intends to be a thought-provoking new concept to substantiate development of operations and maintenance performance indicators for industrial asset maintenance.This is in line with an on going joint industry project on development and implementation of maintenance performance indicators for the petroleum industry in Norway.
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| 35. |
- Liyanage, Jayantha P., et al.
(author)
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Process of maintenance performance management and its imperatives within the offshore petroleum industry : Part-I: The emerging environment for asset maintenance in the new business economy
- 2001
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In: SMRP Solutions. - 1552-5082. ; :4
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Journal article (other academic/artistic)abstract
- In this series, we advocate that the starting point for any measurement system in the current business environment is the need to move away from classical cost and profit perspectives to more valuebased perspectives. Accordingly, we discuss the emerging environment for asset maintenance that is foundational for new frameworks to develop operations and maintenance performance indicators for industrial asset maintenance. The issues discussed in this series substantiate our new concept termed 'value-based maintenance performance management'. This is in line with an ongoing joint industry project on development and implementation of maintenance performance indicators for the petroleum industry in Norway.
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| 36. |
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| 37. |
- Liyanage, Jayantha P., et al.
(author)
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Towards a value-based view on operations and maintenance performance management
- 2003
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In: Journal of Quality in Maintenance Engineering. - : Emerald. - 1355-2511 .- 1758-7832. ; 9:4, s. 333-350
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Journal article (peer-reviewed)abstract
- Most of the North Sea oil companies have recognized the need to adjust their management processes, including those concerned with operations and maintenance, to the changed and changing business conditions in industry at large, particularly due to the volatile oil price. This has been a rationale to review organizational operations and maintenance policies by many. This paper describes findings from a research study on operations and maintenance performance conducted in the emerging operating environment with close cooperation of leading oil and gas organizations in the Norwegian continental shelf. An attempt has been made to develop an architecture for effective management of operations and maintenance performance linking results to performance drivers. This has further been extended to apply the balanced scorecard concept. The papers emphasize on the value rather than the cost of operations and maintenance in the emerging business environment, and stresses that there is a need to move from a plant-based policy to a more or less long-term business-oriented approach.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
- Migdalas, Athanasios, et al.
(author)
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Nonlinear optimization and parallel computing
- 2003
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In: Parallel Computing. - 0167-8191 .- 1872-7336. ; 29:4 Spec, s. 375-391
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Journal article (peer-reviewed)abstract
- The new computational technologies are having a very strong influence on numerical optimization, in several different ways. Many researchers have been stimulated by the need to either conform the existing numerical techniques to the new parallel architectures or to devise completely new parallel solution approaches. A mini-symposium on Parallel Computing in Nonlinear Optimization was held in Naples, Italy, September 2001, during the International Conference ParCo2001, in order to bring together researchers active in this field and to discuss and share their findings. Some of the papers presented during the mini-symposium, as well as additional contributions from other researchers are collected in this special issue. Clearly, two different trends, well representative for most of the current research activities, can be identified. Firstly, there is an attempt to encapsulate parallel linear algebra software and algorithms into optimization codes, particularly codes implementing interior point strategies for which the linear algebra issues are very critical, and secondly, there is an effort to devise new parallel solution strategies in global optimization, either for specific or general purpose problems, motivated by the large size and the combinatorial nature of them. In the present paper we review the literature on these trends and classify the contributed papers within this framework
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| 44. |
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| 45. |
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| 46. |
- Sanyal, S., et al.
(author)
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Polymorphisms in DNA repair and metabolic genes in bladder cancer
- 2004
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In: Carcinogenesis. - 0143-3334. ; 25:5, s. 729-34
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Journal article (peer-reviewed)abstract
- We investigated the association of urinary bladder cancer with genetic polymorphisms in the xeroderma pigmentosum complementation group C (XPC), group D (XPD) and group G (XPG), X-ray repair cross-complementing group 1 (XRCC1) and group 3 (XRCC3), Nijmegen breakage syndrome 1 (NBS1), cyclin D1, methylene-tetrahydrofolate reductase (MTHFR), NAD(P)H dehydrogenase quinone 1 (NQO1), H-ras and glutathione S-transferase theta 1 (GSTT1) genes. Bladder cancer patients from the different hospitals in Stockholm County Council area and matching controls were genotyped for different polymorphisms. The frequency of the variant allele for A/C polymorphism in exon 15 of the XPC gene was significantly higher in the bladder cancer cases than in the controls (OR 1.49, 95% CI 1.16-1.92, P = 0.001). The variant allele homozygote genotype for the T/C polymorphism in exon 1 of the H-ras gene was associated with a decreased risk for bladder cancer (OR 0.12, 95% CI 0.02-0.67, P = 0.006). The variant allele genotypes for the single nucleotide polymorphisms (SNPs) in DNA repair genes, XPG and NBS1, showed a marginal association with the occurrence of bladder cancer (OR 0.38, 95% CI 0.15-0.94, P = 0.03 and OR 1.64, 95% CI 0.92-2.90, P = 0.09, respectively). We also report a positive correlation between the null homozygote of GSTT1 with the risk of bladder cancer (OR 2.54, 95% CI 1.32-4.98, P = 0.003). For other polymorphisms included in this study, NBS1 Glu185Gln, XPD Lys751Gln, XPG Asp1104His, XRCC1 Arg399Gln, XRCC3 Thr241Met, cyclin D1 Pro242Pro, MTHFR Ala222Val and Glu429Ala, NQO1 Arg139Trp and Pro187Ser, no significant differences for genotype distributions and allele frequencies between the bladder cancer cases and the controls were observed in the present study.
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| 47. |
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| 48. |
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