The Dependence of the Field Decay on the Powering History of the LHC Superconducting Dipole Magnets

The decay of the allowed multipoles in the Large Hadron Collider (LHC) dipoles is expected to perturb the beam stability during the particle injection. The decay amplitude is largely affected by the powering history of the magnet and is particularly dependent on the pre-cycle flat-top current and duration as well as the pre-injection preparation duration. With possible prospects of having different genres of cycles during the LHC operation, the powering history effect must be taken into account in the Field Description Model for the LHC and must hence be corrected during machine operation. This paper presents the results of the modelling of this phenomenon

The Field Description Model for the LHC Quadrupole Superconducting Magnets

The LHC control system requires an accurate forecast of the magnetic field and the multipole field errors to reduce the burden on the beam-based feed-back. The Field Description for the LHC (FIDEL) is the core of this forecast system and is based on the identification and physical decomposition of the effects that contribute to the total field in the magnet apertures. The effects are quantified using the data obtained from series magnetic measurements at CERN and they are consequently modelled empirically or theoretically depending on the complexity of the physical phenomena. This paper presents a description of the methodology used to model the field of the LHC magnets particularly focusing on the results obtained for the LHC main quadrupoles (MQ) and insertion region wide aperture quadrupoles (MQY)

Political risk in light rail transit PPP projects

Since 2003 public-private partnerships (PPPs) have represented between 10 and 13.5% of the total investment in public services in the UK. The macro-economic and political benefits of PPPs were among the key drivers for central government's decision to promote this form of procurement to improve UK public services. Political support for a PPP project is critical and is frequently cited as the most important critical success factor. This paper investigates the significance of political support and reviews the treatment of political risk in a business case by the public sector project sponsor for major UK-based light rail transit PPP projects during their development stage. The investigation demonstrates that in the early project stages it is not traditional quantitative Monte Carlo risk analysis that is important; rather it is the identification and representation of political support within a business case together with an understanding of how this information is then used to inform critical project decisions

PIONIER: a visitor instrument for the VLTI

PIONIER is a 4-telescope visitor instrument for the VLTI, planned to see its first fringes in 2010. It combines four ATs or four UTs using a pairwise ABCD integrated optics combiner that can also be used in scanning mode. It provides low spectral resolution in H and K band. PIONIER is designed for imaging with a specific emphasis on fast fringe recording to allow closure-phases and visibilities to be precisely measured. In this work we provide the detailed description of the instrument and present its updated status.Comment: Proceedings of SPIE conference Optical and Infrared Interferometry II (Conference 7734) San Diego 201

Nonlinearity and disorder: Classification and stability of nonlinear impurity modes

We study the effects produced by competition of two physical mechanisms of energy localization in inhomogeneous nonlinear systems. As an example, we analyze spatially localized modes supported by a nonlinear impurity in the generalized nonlinear Schr\"odinger equation and describe three types of nonlinear impurity modes --- one- and two-hump symmetric localized modes and asymmetric localized modes --- for both focusing and defocusing nonlinearity and two different (attractive or repulsive) types of impurity. We obtain an analytical stability criterion for the nonlinear localized modes and consider the case of a power-law nonlinearity in detail. We discuss several scenarios of the instability-induced dynamics of the nonlinear impurity modes, including the mode decay or switching to a new stable state, and collapse at the impurity site.Comment: 18 pages, 22 figure

Mapping preictal and ictal haemodynamic networks using video-electroencephalography and functional imaging

Ictal patterns on scalp-electroencephalography are often visible only after propagation, therefore rendering localization of the seizure onset zone challenging. We hypothesized that mapping haemodynamic changes before and during seizures using simultaneous video-electroencephalography and functional imaging will improve the localization of the seizure onset zone. Fifty-five patients with ≥2 refractory focal seizures/day, and who had undergone long-term video-electroencephalography monitoring were included in the study. ‘Preictal' (30 s immediately preceding the electrographic seizure onset) and ictal phases, ‘ictal-onset'; ‘ictalestablished' and ‘late ictal', were defined based on the evolution of the electrographic pattern and clinical semiology. The functional imaging data were analysed using statistical parametric mapping to map ictal phase-related haemodynamic changes consistent across seizures. The resulting haemodynamic maps were overlaid on co-registered anatomical scans, and the spatial concordance with the presumed and invasively defined seizure onset zone was determined. Twenty patients had typical seizures during functional imaging. Seizures were identified on video-electroencephalography in 15 of 20, on electroencephalography alone in two and on video alone in three patients. All patients showed significant ictal-related haemodynamic changes. In the six cases that underwent invasive evaluation, the ictal-onset phase-related maps had a degree of concordance with the presumed seizure onset zone for all patients. The most statistically significant haemodynamic cluster within the presumed seizure onset zone was between 1.1 and 3.5 cm from the invasively defined seizure onset zone, which was resected in two of three patients undergoing surgery (Class I post-surgical outcome) and was not resected in one patient (Class III post-surgical outcome). In the remaining 14 cases, the ictal-onset phase-related maps had a degree of concordance with the presumed seizure onset zone in six of eight patients with structural-lesions and five of six non-lesional patients. The most statistically significant haemodynamic cluster was localizable at sub-lobar level within the presumed seizure onset zone in six patients. The degree of concordance of haemodynamic maps was significantly better (P < 0.05) for the ictal-onset phase [entirely concordant/concordant plus (13/20; 65%) + some concordance (4/20; 20%) = 17/20; 85%] than ictal-established [entirely concordant/concordant plus (5/13; 38%) + some concordance (4/13; 31%) = 9/13; 69%] and late ictal [concordant plus (1/9; 11%) + some concordance (4/9; 44%) = 5/9; 55%] phases. Ictal propagation-related haemodynamic changes were also seen in symptomatogenic areas (9/20; 45%) and the default mode network (13/20; 65%). A common pattern of preictal changes was seen in 15 patients, starting between 98 and 14 s before electrographic seizure onset, and the maps had a degree of concordance with the presumed seizure onset zone in 10 patients. In conclusion, preictal and ictal haemodynamic changes in refractory focal seizures can non-invasively localize seizure onset at sub-lobar/gyral level when ictal scalp-electroencephalography is not helpfu

Climatic change and the Mediterranean

The temperature and precipitation scenarios for the Malta region developed by the Climate Research Unit of the University of East Anglia suggest that annual temperature will increase by 0.8 to 0.9°C per degree Celsius of global change and that there will be little if any change in the annual rainfall amounts around Malta. A statistical analysis of past meteorological data for Malta indicates an existing trend towards increasing extremes of temperature; namely an increase in the maximum and a decrease in the minimum temperatures. The mean annual temperature is also apparently increasing. These data also suggest a trend towards lower total annual rainfall; an increase in the atmospheric pressure; an increase in the number of days with thunderstorms; and decreases in cloud cover and the number of hours of bright sunshine. These trends suggest that a process of desertification is already occurring in Malta, and that there is an increase in the suspended particle concentration including pollutants, in the atmosphere over the island. The hydrological cycle will be significantly affected by global warming. In Malta, natural sources of freshwater account for about 37% of all potable water in the public supply and for 84% of all irrigation water. Global warming will affect the freshwater supply through changes to relative sea level, and through changes in rainfall and evapotranspiration. A eustatic rise in sea level of around 65 ± 35 cm by the year 2100 would adversely affect the existing extraction rates from Malta's principal aquifer and make it more vulnerable to sea water intrusion. In contrast, the direct climatic effect will be less pronounced, since only a small change in local precipitation is predicted to accompany global warming. Climate is a fundamental factor influencing the nature of the soils of Malta. Since an increase in temperature with little change in the total rainfall is anticipated, evapotranspiration will increase, leading to an increase in aridity, and to soil degradation mainly due to salinization and alkalinization. The anticipated increase in temperature; a shift in precipitation patterns; a decrease in soil water availability; and a rise in sea level, will have negative impacts on agriculture, natural vegetation and associated fauna, favouring an increase in xerophilic, thermophilic and halophilic species. Such species are likely to be introduced ones, thriving at the expense of native species. It is predicted that the character of the vegetation will change from that typical of Mediterranean coastal lowlands, to associations more typical of deserts. This shift in vegetation pattern would be enhanced by soil erosion and increased soil salinity. Remedial action at a local level could include measures to prevent soil erosion by gradually changing to crops and trees that stabilize soils and which tolerate the new climatic conditions. A change in temperature could possibly lead to an increase in agricultural pests, whilst sea level rise may cause inundation of low-lying agricultural land such as that at Pwales and of groves such as those at Salina Bay. The impacts on fisheries may be less dramatic but changes in migration patterns of important fish such as lampuki might happen; and the potentially adverse effects which competitive thermophilic seaweeds may have on the important Posidonia meadows may be of concern in the future. The effects on aquaculture are difficult to assess but may include an increase in pathogens. The control of pollutants and protection of the Posidonia meadows are recommended, together with development of more sustainable use of fisheries resources. The present coastal, near-shore and freshwater ecosystems are threatened by a number of anthropogenic, non-climatic changes. Any additional impacts on these ecosystems resulting from climatic changes will have to be assessed in the light of such nonclimatic effects, if the overall projections of future changes are to be accurate. Increased eutrophic conditions and increased water stratification are likely to occur under conditions of global change in certain localities already influenced by other non-climatic human activities. Non-linear biological responses to climatic changes are discussed and may prove to be quite significant but difficult to predict with the present state of knowledge. Coastal sandy beaches, sand dunes and saline marsh habitats are considered to be sensitive to predicted climate change impacts, through increased erosion, enhanced shoreline recession and increased environmental fluctuations. The extent of impacts on such habitats, under less severe climatic change scenarios, will depend largely on present and future land-use management practices. Given the coastal topography, present drainage patterns and negligible tectonic movements in Malta, the predicted rise in sea level will have coast and especially those in the main drainage basins will become more susceptible to periodic rainfall-induced flooding and anticipatory action will be needed to address the consequential economic and social disruption. Impacts on coastal settlements are expected as a result of tidal and storm surges rather than from permanent inundation. A rise in sea level may cause sewage systems to flood, and new systems may have to be developed to reduce public health risks from such a hazard, including the increased risk of epidemics of enteric disorders such as typhoid fever. Salt water intrusion into aquifers will reduce the quantity and quality of potable water resources. Temperature rise and an increased frequency of extreme high temperatures, especially when combined with high humidity, will put some population groups such as the elderly and infants at risk from heat stress. Diseases presently confined to the tropics may spread to higher latitudes, and tropical and sub-tropical vector borne diseases may become more widespread, partly because vector survival will increase and partly because the parasites may be able to complete their life cycle more easily. Malaria may reappear in Europe, whilst Leishmaniasis, which has been under control in the recent past, already seems to be on the increase, possibly as a result of recent increases in temperature and humidity. Increased exposure to the sun when combined with possible ozone layer depletion may result in a further rise in the incidence of both melanomas and non-melanotic skin cancers. Exposure to increased ultraviolet (UV) radiation is expected to cause damage to the cornea and lens and an increased incidence of cataracts. The effect of UVB radiation on the human immune system is far less well understood, but it is a well accepted fact however, that UV, possibly acting through DNA damage, is an important precipitating factor of the auto-immune condition, systemic lupus erythematosus. The tourist industry has, for many years, been one of the Islands' most important economic activities, employing 5.8% of the total working population. If the climate conditions of the Maltese Islands change, the tourist industry could suffer, causing disruption to the Maltese economy and hardship to the population. Sea level rise will certainly have an impact on this site-dependent and coastal industry, which would be adversely affected by the loss of sandy beaches and the reduction in potable water supply. The tourist industry, is by its very nature, fragile and susceptible to political, economic and social changes. Climate change will add another element of uncertainty to this sector. Transport in Malta depends entirely on roads, whilst a ferry service connects the islands of Malta, Gozo and Comino and is also used around the Grand Harbour area. Road traffic would suffer in the event of flooding of the main traffic arteries as a result of severe rain storms, which will probably increase along with the anticipated increase in autumn precipitation. Changes in climate are expected to have an effect on the patterns of energy demand to heat and cool buildings. Electricity generation, which accounts for almost two thirds of primary energy consumption, has grown on average by about 8.5% per year in recent years. The predicted average temperature increases would, theoretically, reduce the need to provide heating, thereby saving energy. Given the low thermal performance of Maltese buildings, an increase in ambient temperature may merely result in a more thermally comfortable interior, rather than a saving of energy. · In the commercial and industrial sectors, the interhal heat generated by the use of machinery is high and an increase in ambient temperature, may result in a need for cooling through increased ventilation and possibly an extension of the air conditioning season. The introduction of thermal insulation to the building envelope, would reduce both the heating demand in winter as well as the cooling demand in summer. The displacement of fossil fuels by renewable energy sources particularly biomass and hydro power would reduce carbon dioxide emissions. In Malta there is good potential for development of solar energy, although land availability is a major obstacle. There is less possibility of harnessing wind energy on a large scale although wind energy is already widely used for water pumping in agriculture.peer-reviewe