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Byline: Jones, J. C. With these accidents, has refining internationally fallen sub-standard in terms of safety? Such a question is likely best addressed by examining the existing HPI standard. Three [...]

Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1–6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7–9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10−6to 1012electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.

This paper examines the impact of the 1987 changes in the Canadian Patent Act on the pricing of ethical drugs. From 1969 to 1987 Canada opted to control pharmaceutical prices [...]

Focuses on the sexual life of a yellow-fever mosquito. Fertilization of the egg; Process of copulation with a female mosquito; Behavior of the sperm in the female's reproductive tract.

This paper reports the results of estimating a single equation model of an attendance function for British Rugby League over the seasons 1982/83 to 1990/91. The data are panel data [...]

Context. Reports on a transient source about 1.25° south of the Galactic Centre motivated these follow-up observations with the WSRT and the reinvestigation of archival VLA data. The source GCRT J1745-3009 was detected during a 2002 Galactic Centre monitoring programme with the VLA at 92 cm by five powerful 10-min bursts with a 77-min recurrence while apparently lacking any interburst emission.

Context.Some O stars are suspected to have to have (weak) magnetic fields because of the observed cyclical variability in their UV wind-lines. However, direct detections of these magnetic fields using optical spectropolarimetry have proven to be very difficult.

We present the first results of our X-ray monitoring campaign on a 1.7 square degree region centered on Sgr A* using the satellites XMM-Newtonand Chandra. The purpose of this campaign is to monitor the behavior (below 10 keV) of X-ray sources (both persistent and transient) which are too faint to be detected by monitoring instruments aboard other satellites currently in orbit (e.g., Rossi X-ray Timing Explorer; INTEGRAL). Our first monitoring observations (using the HRC-I aboard Chandra) were obtained on June 5, 2005. Most of the sources detected could be identified with foreground sources, such as X-ray active stars. In addition we detected two persistent X-ray binaries (1E 1743.1–2843; 1A 1742–294), two faint X-ray transients (GRS 1741.9–2853; XMM J174457–2850.3), as well as a possible new transient source at a luminosity of a few times 1034erg s-1. We report on the X-ray results on these systems and on the non-detection of the transients in follow-up radio data using the Very Large Array. We discuss how our monitoring campaign can help to improve our understanding of the different types of X-ray transients (i.e., the very faint ones).

Relativistic jets are observed throughout the Universe and strongly affect their surrounding environments on a range of physical scales, from Galactic binary systems1to galaxies and clusters of galaxies2. All types of accreting black hole and neutron star have been observed to launch jets3, with the exception of neutron stars with strong magnetic fields4,5(higher than 1012gauss), leading to the conclusion that their magnetic field strength inhibits jet formation6. However, radio emission recently detected from two such objects could have a jet origin, among other possible explanations7,8, indicating that this long-standing idea might need to be reconsidered. But definitive observational evidence of such jets is still lacking. Here we report observations of an evolving jet launched by a strongly magnetized neutron star accreting above the theoretical maximum rate given by the Eddington limit. The radio luminosity of the jet is two orders of magnitude fainter than those seen in other neutron stars with similar X-ray luminosities9, implying an important role for the properties of the neutron star in regulating jet power. Our result also shows that the strong magnetic fields of ultra-luminous X-ray pulsars do not prevent such sources from launching jets.

Liquid crystal lenses are an emerging technology that can provide variable focal power in response to applied voltage. Many designs for liquid-crystal-based lenses are polarization dependent, so that 50% of light is not focused as required, making polarization-independent technologies very attractive. Recently, the dark conglomerate (DC) phase, which is an optically isotropic liquid crystalline state, has been shown to exhibit a large change in refractive index in response to an applied electric field (Δn=0.04). This paper describes computational modeling of the electrostatic solutions for two different types of 100 μm diameter liquid crystal lenses, which include the DC phase, demonstrating that it shows great potential for efficient isotropic optical switching in lenses. A feature of the field dependence of the refractive index change in the DC phase is that it is approximately linear in a certain range, leading to the prediction of excellent optical quality for driving fields in this regime. Interestingly, a simulated microlens is shown to exhibit two modes of operation: a positive lens based upon a uniform bulk change in refractive index at high voltages, and a negative lens resulting from the induction of a gradient index effect at intermediate voltages.

Dual-stage actuators, which combine two actuators with different characteristics, have gained interest due to their large-range, high-resolution positioning capabilities. Control of such systems is challenging because it requires balancing the relative contributions of the individual actuators in terms of speed, range, and precision. The most common approach is to allocate effort to the actuators based on frequency but this can lead to misallocation in the case of low-frequency short-range trajectories. In this paper, the problem of trajectory allocation in dual-stage actuator systems is addressed using a recently developed range-based filter. The theoretical basis of the range-based filter is rigorously derived for the first time and insights regarding its use, specifically its reinterpretation as a speed-based filter, and its range-frequency response characteristics are presented. The new analysis not only explains the behavior of the filter clearly, but it provides a more robust strategy for incorporating range constraints in filter design for different desired trajectories.

Conduction laser welding involves initiating a melt pool by exposure to high power laser induced light and controlled thermal conduction. Existing welding techniques generally provide enough energy to join the component but have no real control over the melt pool. This process can invariably lead to overheating in adjacent areas or even the melt pool itself, often causing unavoidable effects, such as ‘burn through’. The present work presents a procedure in which a desired melt pool shape is conceived, and a bespoke beam irradiance distribution is designed to match. The beam is shaped not by conventional lenses but by a diffractive holographic optical element (DHOE). The DHOE utilises holography to wholly create highly complex three-dimensional energy distributions through constructive and destructive interference. This technique allows novel beam irradiance distributions to be applied to conduction mode laser welding, with the melt pool transverse profile being shaped to a specific design. Holographic conduction laser welding has been shown to be successful and represents a significant step forward in the industry, as demonstrated in this case in both mild and stainless steels. The fusion zone is shown to be particularly influenced by the shape of the illuminating laser beam profile, and many of the welds demonstrate a highly novel weld profile because of this. The use of a bespoke beam irradiance distribution allows control of the heat flow to the workpiece, and this allows greater control over material migration due to surface tension effects. Many of the welds demonstrate unique surface solidification patterns directly linked to the beam profile used. The DHOE also presents a number of additional advantages, such as an increased usable depth of field, allowing for less stringent set-up tolerances. Comprehensive metallography has been performed on samples of these welds through the use of optical microscopy, electron microscopy, electron backscatter diffraction and energy dispersive (X-ray) spectroscopy. These techniques offer in depth analysis of crystal size, shape, orientation and phase. By incorporating DHOEs into a laser welding process, not only does the melt pool shape become controllable, but also the crystal growth is highly influenced. Many of the undesirable attributes of a conventional laser weld are reduced by using a beam distribution created by a DHOE, bringing the microstructure of the weld pool closer to that of the parent material.

In this paper, an analysis of knock signals suggests that the knock intensity is a cyclically uncorrelated random process, and that it is therefore not possible to control individual cycles to a specified knock intensity in a deterministic manner. A new knock control algorithm is therefore developed on the basis of a stochastic interpretation of the knock signal, and on the basis of a control objective specified as a certain percentage of knocking cycles. Unlike traditional controllers, the new algorithm does not respond to knock events provided that these are occurring within a specified tolerance of the target knock rate. The new controller uses the cumulative summation of knock events to make this determination, thereby avoiding the slow transient response times sometimes associated with ‘stochastic’ knock controllers. When a spark adjustment is deemed necessary, the magnitude of the control action is scaled according to the likelihood ratio of the observed events since the last spark adjustment was made. A theoretical analysis of the new controller is presented and a simulation tool which is closely based on experimental data is used to assess its performance. The results show that the new controller is able to achieve the same target knock rate as a traditional controller while operating at a more advanced mean spark angle. There is also less cyclic variance about this mean and the regulatory response is significantly improved. The transient response to overly advanced or retarded conditions is similar to the traditional controller. These results suggest that the new controller will deliver increased torque and engine efficiency under knock-limited conditions without increasing the risk of engine damage.

An integrated model-based methodology for three-way automotive catalyst control and diagnostic monitoring is presented in this work. The catalyst controller and monitor both utilize a limited integrator catalyst oxygen storage model with an adaptive integral gain. This adaptive catalyst gain, which is a measure of the catalyst oxygen storage capacity, is used by the controller to provide information on the dynamic catalyst behaviour and by the diagnostic monitor to provide information on long-term catalyst deactivation and short-term emission control device failure. A statistical classification technique based on the fraction of time that the catalyst gain values in a moving window are within a threshold of zero is employed as the test metric for on-board diagnostic monitoring. The performance of the catalyst monitor is demonstrated with experimental vehicle test data from a 4.6 l ULEV II gasoline engine operated over a series of Environmental Protection Agency Federal Test Procedure drive cycles with differently aged catalysts. Preliminary results indicate that it is possible to perform very accurate discrimination between catalyst operation, even near the on-board diagnostic detection threshold, using this technique.

AbstractOur recent discovery of hazardous concentrations of arsenic in shallow sedimentary aquifers in Cambodia raises the spectre of future deleterious health impacts on a population that, particularly in non-urban areas, extensively use untreated groundwater as a source of drinking water and, in some instances, as irrigation water. We present here small-scale hazard maps for arsenic in shallow Cambodian groundwaters based on >1000 groundwater samples analysed in the Manchester Analytical Geochemistry Unit and elsewhere. Key indicators for hazardous concentrations of arsenic in Cambodian groundwaters include: (1) well depths greater than 16 m; (2) Holocene host sediments; and (3) proximity to major modern channels of the Mekong (and its distributary the Bassac). However, high-arsenic well waters are also commonly found in wells not exhibiting these key characteristics, notably in some shallower Holocene wells, and in wells drilled into older Quaternary and Neogene sediments.It is emphasized that the maps and tables presented are most useful for identifying current regional trends in groundwater arsenic hazard and that their use for predicting arsenic concentrations in individual wells, for example for the purposes of well switching, is not recommended, particularly because of the lack of sufficient data (especially at depths >80 m) and because, as in Bangladesh and West Bengal, there is considerable heterogeneity of groundwater arsenic concentrations on a scale of metres to hundreds of metres. We have insufficient data at this time to determine unequivocally whether or not arsenic concentrations are increasing in shallow Cambodian groundwaters as a result of groundwater-abstraction activities.

Using semi-quantitative arguments based on the principles of stoichiometry and ignition limits the behaviour of a flammable vapour in a microcalorimeter is analysed. As acknowledged at the end of the paper, the author has also used input by an investigator other than himself in preparing a synthesis suitable for publication.

A natural gas device for the preparation of fresh water from salt water is known to have been in successful use in China 2500 years ago. Here the facts, as far as they are known, are interpreted according to modern principles. The conclusion is that the developers were remarkably fortunate in that three relevant quantities fixed by nature were such that their design worked. This is demonstrated in semiquantitative terms in what follows.

Viton is examined in a microcalorimeter and found to display a nil signal, indicating no heat release. Viton having imbibed an organic solvent mixture releases heat quite powerfully. The results are interpreted along the lines of mutual sensitisation to oxidation of the viton and the solvent.

Previously reported results for the Biot number in an oven heating test have been utilised in the calculation of convection coefficients, both to the sample itself and to a thermocouple measuring the oven temperature. A full heat balance on the thermocouple tip is performed in order to predict the accuracy with which the oven temperature - utilised in calculations following from oven heating experiments - can be measured.

Results in a microcalorimeter for a UK anthracite coal at temperatures of 60 and 70°C are found to display a considerable spread which is tentatively attributed to petrographic variations between the samples. Results are compared with previously reported ones for a low-rank coal in the same instrument at lower temperatures.

Following recent related work on anthracite, the authors have examined, with a microcalorimeter, the behaviour of activated carbons in air at 70 C. It appears that small samples (<150 mg) exhibit an overall endotherm, most probably attributable to dehydrogenation.

Mathematical modeling of three-way catalytic converter (3WCC) operation is increasingly employed in automotive catalyst and converter systems optimization. Oxygen storage is known to strongly affect catalytic converter operation under real world transient operating conditions. This paper presents a modeling approach embodying a comprehensive oxygen storage and release submodel into an existing 3WCC quasi-steady model. The dynamic model developed according to this approach is validated against previously published experimental data. The model sensitivity to each of the oxygen storage parameters is examined. The results of this investigation encourage further application of mathematical modeling in areas such as air-to-fuel (A/F) ratio control strategy optimization, which lie beyond the scope of traditional kinetic 3WCC models.

Lead scandium titanate (PST) thin films were deposited by RF dual magnetron sputtering and then annealed either by vacuum furnace or combined rapid thermal annealing (RTA) and furnace anneal. The film structure was investigated by x-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy techniques. Lead loss was more severe using furnace annealing than the combined RTA and furnace anneal. The annealed films were characterized by the presence of voids and exhibited relaxor ferroelectric characteristics. PST perovskite crystal grains were found to co-exist with pyrochlore matrix in the furnace-only annealed films, whilst in RTA annealed films no apparent pyrochlore morphology was observed in the TEM image. Lead was found to diffuse through the bottom electrode Pt layer during the annealing. Films treated by combining RTA and furnace annealing have shown pyroelectric coefficients under field of up to 500 µC m^-2 K^-1, a dielectric loss of below 0.007 and a merit figure for thermal detection of 2.5×10^-5 Pa^-1/2.

Hot spot theory is applied to the contents of a laundry tumble dryer in order to predict how far above the dryer temperature an item previously rendered “hot” by reason of oil or solvent contamination would need to be in order to cause ignition of the dryer contents.

The reported flash point of benzoic acid is examined in terms of vapour pressures and stoichiometric proportions and found to be significantly aberrant. A possible explanation is that during heating in the flash point apparatus there is decarboxylation catalysed by the metal surface.

A simple means of estimating fireball temperatures, for particular sizes of leakage, is developed on the basis of the use of a previously existing plot of radiation heat transfer against time as a “template.” Such calculations are performed for large and small propane fireballs.

Flash points for four liquid organic compounds—m-Xylene, n-butanol, n-decane and n-dodecane—are calculated on the principle that the fire point occurs when the pressure of the vapour is 1.5 times the stoichiometric value. Fire points so calculated are compared with experimental values from the literature, and agreement is very good.

Using blends of an organic polymeric material and sand and gravel, solid fuels of widely varying ash content are simulated and their thermal diffusivities are determined experimentally. The results are processed in terms of the product (thermal diffusivity × bulk density), as a function of the organic fraction, and tested against previously reported experimental results for high-ash low-rank coals, with very gratifying agreement.

Dexamethasone administration has marked effects on the growth hormone-insulin-like growth factor axis (GH-IGF) in animal and human studies. During pregnancy in the rat, it is associated with fetal growth restriction due to inhibition of IGF bioactivity. In the human only repeated dosages have been associated with fetal growth restriction. The aim of this study is to test the hypothesis that antenatal dexamethasone administration to pregnant women is associated with reduced activity of the GH-IGF axis. To achieve this blood samples were taken from 12 pregnant women pre- and at 24 h and 48 h after dexamethasone administration. In these samples GH, IGF-I, IGF bioactivity and IGF binding protein (IGFBP)-3 protease activity were measured. In view of the interaction between insulin and the GH-IGF axis, glucose and insulin concentrations were also measured. There were no significant differences between the concentrations of GH, IGF-I, IGF bioactivity and IGFBP-3 protease activity before and after dexamethasone. The concentrations of glucose and insulin were significantly higher at 24 h, but not 48 h post-dexamethasone. It is concluded that a single antenatal course of dexamethasone does not alter the GH-IGF-I axis in pregnant women at the time points studied.

Zenithal Bistable display devices have been made which are compatible in size and functionality with current mobile phone or pager displays. Radical improvements in the viewing characteristics particularly in reflective mode are shown. Furthermore this paper describes: low voltage operation; fast latching times; and broad‐margin matrix addressing.

A defect structure has been observed for certain ferroelectric liquid crystal mixtures in the surface stabilised device geometry when cooled towards ambient temperature. X-ray and electro-optic studies suggest that the sample, initially in the chevron layer structure, forms a uniformly tilted layer structure spontaneously. This seriously degrades device contrast and switching properties. The effect of both liquid crystal composition and alignment layer pretilt are reported and recommendations made to ensure that the defect does not occur, thereby allowing good device performance to be maintained.

The transcriptional coactivator p300 is essential for normal embryonic development and cellular differentiation. We have been studying the role of p300 in the transcription of a variety of genes, and we became interested in the role of this coactivator in the transcription of genes important in breast epithelial cell biology. From MCF-10A cells (spontaneously immortalized, nontransformed human breast epithelial cells), we developed cell lines that stably overexpress p300. These p300-overexpressing cells displayed reduced adhesion to culture dishes and were found to secrete an extracellular matrix deficient in laminin-5. Laminin-5 is the major extracellular matrix component produced by breast epithelium. Immunofluorescence studies, as well as experiments using normal matrix, confirmed that the decreased adhesion of p300-overexpressing cells is due to laminin-5-deficient extracellular matrix and not due to loss of laminin-5 receptors. Northern blots revealed markedly decreased levels of expression of two of the genes (designated LAMA3 and LAMC2) encoding the alpha3 and gamma2 chains of the laminin-5 heterotrimer in the cells that overexpress p300, whereas LAMB3 mRNA, encoding the third or beta3 chain of laminin-5, was not markedly reduced. Transient transfection experiments with a vector containing a murine LAMA3 promoter demonstrate that overexpressing p300 down-regulates the LAMA3 promoter. In summary, overexpression of p300 leads to down-regulation of laminin-5 production in breast epithelial cells, resulting in decreased adhesion.

To examine the relationship of preoperative fluorodeoxyglucose (FDG)-PET asymmetry in temporal lobe metabolism and memory outcome after anterior temporal lobectomy (ATL).

The current test procedure for propensity to spontaneous heating, results from which might sometimes be expected to stand up in law, have in recent years been shown to be flawed. In the last two years significant progress has been made both towards correcting the basis of the current test method and developing an entirely new one. These are described herein against a background of a review of other advances in the approach since the 1970s. Copyright © 1999 John Wiley & Sons, Ltd.

Previously, we demonstrated that proteolytic processing within the globular domain of the alpha3 subunit of laminin-5 (LN5) converts LN5 from a cell motility-inducing factor to a protein complex that can trigger the formation of hemidesmosomes, certain cell-matrix attachment sites found in epithelial cells. We have prepared a monoclonal antibody (12C4) whose epitope is located toward the carboxy terminus of the globular domain of the alpha3 laminin subunit. This epitope is lost from the alpha3 subunit as a consequence of proteolytic processing. Antibody 12C4 stains throughout the matrix of cells that fail to process the alpha3 laminin subunit, but does not recognize the matrix of confluent cultures of MCF-10A cells, which efficiently process their alpha3 laminin chain. In subconfluent populations of MCF-10A cells, 12C4 only stains matrix deposited at the outer edges of cell colonies. In these cells, integrin alpha3beta1 occasionally colocalizes with the staining generated by the 12C4 antibody but alpha6beta4 integrin does not. In wounded MCF-10A cell cultures, the 12C4 antibody stains the extracellular matrix beneath those cells at the very edge of the cellular sheet that moves to cover the wound site. A similar phenomenon is observed in human skin wounds, since we also detect expression of the unprocessed alpha3 laminin subunit at the leading tip of the sheet of epidermal cells that epithelializes skin wounds in vivo. In addition, using alpha3 laminin subunit and integrin function-inhibiting antibodies, we provide evidence that LN5 and its two integrin receptors (alpha6beta4 and alpha3beta1) appear necessary for wound healing to occur in MCF-10A cell culture wounds. We propose a model for healing of wounded epithelial tissues based on these results.

An algebraic relationship is derived which enables the generalized amplitude dependent describing function to be expressed in terms of the parameters of a general nonlinear integro-differential equation. The algorithm is not restricted to a specific input, but treats the whole class of harmonically related, phase independent, sinusoidal inputs, and is illustrated by a number of examples.

A relationship between the higher-order frequency response functions of the Volterra series model and the well-known describing function representation for non-linear systems is derived. It is shown that a large class of generalized describing functions can be derived from the Volterra model and that this approach removes the restriction to specific inputs. The concept of a worst case transfer function is introduced, and examples are included to illustrate the results.

Analytical and graphical methods of interpreting generalised frequency response functions for non-linear systems are derived. It is shown that non-linear phenomena can be classified into intra-kernel and inter-kernel interference and that worst-case responses can be computed. The results are illustrated using several discrete- and continuous-time non-linear systems.

The static electro-optic behaviour of achiral smectic C samples in the chevron geometry have been modelled using the continuum theory of Leslie et al. [1]. The model assumes that the layer tilt and smectic C director tilt angle are constant, and treats the layers at the chevron interface as an infinitely bound surface. Comparison of the predicted electro-optic behaviour with experimental results gives values for the bend (B1) and splay (B2) c-director elastic constants. However, more detailed optical studies show that surface and chevron interface terms become important at high values of applied electric field.

1. Captopril given for 5 days caused a fall in blood pressure in normotensive subjects. The percentage fall in mean supine pressure was greatest on a low sodium diet (10 mmol/day), 19.6%, least on a high sodium diet (350 mmol/day), 11%, and in between on a normal sodium diet (120 mmol/day), 16.5%. 2. Captopril caused a marked fall in plasma aldosterone in normal subjects on all three sodium intakes. 3. Captopril caused an increase in sodium excretion on the normal (120 mmol/day) and low (10 mmol/day) sodium diet but not the high sodium diet. 4. These results suggest that the renin-angiotensin-aldosterone system is a normal mechanism for maintaining blood pressure and aldosterone secretion in normotensive man. The system may also be involved in the maintenance of sodium balance. 5. These results may lead to a better understanding of the role of the renin-angiotensin-aldosterone system in the maintenance or causation of high blood pressure in essential hypertension.

Goldstone mode relaxations in surface stabilised thin film ferroelectric liquid crystal (SSFLC) cells have been studied using dielectric relaxation spectroscopy. The results are used to find an effective elastic restoring torque A and viscosity. The variation of the elastic term A with cell thickness has been studied, and an anomalous increase observed in thinner cells.

Surface stabilised ferroelectric liquid crystals (SSFLC) provide fast, bistable, optical modulators suitable for display and other applications. The effect of surface alignments and the resulting director profiles are not fully understood, but can be probed by studying the wavelength dependent optical transmission properties. 5° and 30° evaporated SiO alignments are investigated and it is shown that the surface pretilt affects markedly the director profile.