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The design of a 4× blind analogue-to-digital converter (ADC)-based receiver implemented in 65 nm CMOS technology is presented. The ADC, which has three levels with two adjustable thresholds, effectively implements a speculative decision-feedback equaliser. By reducing the ADC resolution and by simplifying the digital clock and data recovery design, the power consumption is reduced by a factor of 2 compared with previous works. Measurement results confirm a bit error rate of

An existing 15·5 m high main dam embankment at Abberton Reservoir in Essex was completed in August 1938, since when its performance has been satisfactory. However, the upstream embankment shoulder of the original dam suffered a deep-seated failure through its foundation towards the end of construction in July 1937, 9 days before a similar and well-known failure occurred at Chingford Reservoir in close proximity to Abberton. Whereas the failure at Chingford became an important case in the history of soil mechanics through the involvement of Karl Terzaghi and marked one of the first applications of modern soil mechanics principles, the failure at Abberton has remained largely unknown, until recently when raising of the existing dam started to be considered. This paper describes advanced finite-element analyses which were carried out to investigate the failure of the original dam at Abberton and the stability of the existing main dam. The parameters used in the constitutive models were derived on the basis of the available site investigations and laboratory testing and on experience in the back-analysis of other failures in London Clay. The analyses demonstrated that the upstream shoulder of the original embankment failed through the mechanism of progressive failure, which involved the top of the stiff plastic London Clay rather than the overlying alluvium in the foundation. The relatively rapid rate of embankment filling, achieved by using modern earth-moving equipment, contributed significantly to the original dam failure. The analyses also demonstrated satisfactory behaviour of the existing dam during reconstruction, the first impounding and in the long term, with its response being similar to that observed. Thus the constitutive models used and parameters derived were successfully calibrated against the observed behaviour of both the original and existing main dams at Abberton, and could be used in predicting the behaviour of the dam during and after its proposed raising.

Background Introducing patient safety and quality improvement science to medical students is integral to improving healthcare. However, developing and implementing a patient safety curriculum can be challenging in a medical school curriculum that is already densely packed. Our aim was to develop and evaluate the impact of a workshop introducing patient safety and quality improvement science to a large class of first-year medical students. Method As a part of an evolving longitudinal patient safety curriculum, an introductory workshop on patient safety was integrated into an anatomy course. A high impact event (a simulated “retained sponge” discovery during an anatomy dissection lab) was used to introduce medical error. The educational session which followed consisted of a presentation by an interprofessional team utilizing the retained sponge as example of an error. Use of safety tools was introduced and quality improvement science was discussed using the evolution of methods to decrease retained foreign objects during surgery. A patient’s story told by a close family member about the personal impact of medical errors was presented. Students then participated in an interactive breakout activity and completed a module on safety. The impact of the workshop was assessed through pre- and post- session tests. Results Quantitative and qualitative evaluation reflected a positive effect of the session in improving students’ safety knowledge and attitudes. Students’ mean total knowledge improved from 7.58 to 8.98 (p = 0.000). Mean total attitudes score improved from 47.73 to 50.56 (p = 0.000). Students’ comments after the workshop reflected increased awareness and appreciation of the importance of addressing medical errors. Conclusion A workshop introducing patient safety and quality improvement to first year medical students improved knowledge and attitudes regarding safety and increased awareness of the importance of addressing medical errors in their future careers. Integrating patient safety education into an existing foundational science course is a model for teaching patient safety at other medical schools.

Properties of two catalysts tailored in the laboratory conditions by sulfation of commercial Zr-hydroxide and Zr-hydroxide of nitrate origin were compared with those of commercial SO4-Zr-hydroxide. Equally thermally treated samples in the temperature interval 500–700°C, and having the same amount of sulfur, show different properties indicating memory effect of their solid parent materials. The catalyst obtained by sulfation of commercial Zr-hydroxide differs in amount of residual sulfates upon calcination from other two catalysts. The instability of sulfates in the previous case might be connected to the lowest surface area values of catalyst and the highest fraction of monoclinic phase observed at all applied calcination temperatures.

Empingham Dam was built in the early 1970s on a brecciated Upper Lias Clay foundation of fill derived from it. When the dam was designed, the undrained behaviour of intact stiff plastic clay in the field was poorly understood. Thus, a conservative bound to conventional strength tests was adopted to provide an undrained strength profile in the foundation. The shearing resistance of the foundation was also investigated by incorporating an instrumented 24 m high trial bank in the upstream berm of the main dam. As the trial bank was nearing completion, two slips occurred in temporary borrow pit slopes. It was considered that this field experience, together with undrained triaxial tests with pore pressure measurement on large diameter samples carried out in the laboratory, justified the original design assumptions. However, the end lengths of the main embankment on the undrained foundation started to spread laterally when the fill was some 2 m below the final level. This was in spite of the fact that the conventional factor of safety, calculated using the original design assumptions, was in excess of two. This paper describes the finite element (FE) back analysis of the observed behaviour. For this purpose two different constitutive models have been employed: a kinematically hardening ‘bubble’ model accounting for pre-peak plasticity, and a non-linear elastic Mohr-Coulomb plastic model accounting for strain-softening. It is demonstrated that the observed undrained behaviour of the Empingham foundation can be reproduced by FE analyses, but only if the undrained shearing resistance varies from section to section.

The paper describes the results of finite element analyses of the temporary slope geometries in London Clay at London Heathrow Airport's Terminal 5. The aims of the analyses were to examine the times before failures developed, and to identify the failure mechanisms involved. The brittle behaviour of the London Clay was modelled, and the effects of progressive failure were taken into account. The possible presence of tectonic shears with their strength close to residual was considered by comparing analyses with and without a tectonic shear zone. The predicted time to failure of the slopes and the form of the failure, whether shallow or deep-seated, were determined by a combination of the assumed permeability profile and whether or not allowances were made for increases in permeability as the clay swelled, the average surface suction, the in situ K0 profile, the depth of excavation, and whether or not a low-strength tectonic shear surface was present in the slope. The analyses fall into the category of Class A predictions, and were used in the assessment of how long temporary slopes to deep excavations could be left open before backfilling, and how the slopes should be monitored.

Compaction grouting involves the injection of stiff grout that does not penetrate the ground. Bulbs of grout are formed. It is applied to free-draining granular soils. The aim is to increase the density of the soil being treated by applying high local pressure. The design of compaction grouting is based largely on experience and empiricism. If the soil is not sufficiently permeable for consolidation to occur as it is treated, excess pore pressures may be generated, which will dissipate after treatment. The potential effect of such excess pore pressures on the compaction achieved is considered here. It is found that the efficiency of treatment may be reduced substantially.

Delayed failure of railway cutting slopes in stiff clays excavated in the nineteenth and early twentieth centuries has been studied for some forty years. Known failures have generally been deep-seated. More recently failures have been a problem in the slopes of motorway cuttings and embankments, although generally these have been shallow. The average operational strength at failure in these slides has been significantly less than the peak strength, and progressive failure has been postulated as the probable cause of this. Progressive failure can now be analysed using advanced numerical techniques. A series of coupled finite element analyses have been conducted assuming strain-softening soil with properties based on the Brown London Clay, and the results are reported. They show that progressive failure is considerable, and fully explain the observed field behaviour. The delays experienced in the field are also recovered by the analyses. Progressive failure is generated primarily by the high lateral stresses in the soil prior to excavation. The rupture surface generated spreads horizontally from the toe as the soil swells, and differs significantly from the critical surface predicted by limit equilibrium analysis. The average strength on it at collapse is significantly lower than that obtained by back analysis by limit equilibrium methods. It becomes lower as lateral stress increases, but the effect is compensated by the increasing depth of rupture. The roll of the hydraulic surface boundary condition, which is controlled by climate, is important in controlling collapse. The implications of the findings for monitoring and for remedial works in existing slopes is discussed.

This paper describes advanced finite-element simulations of a geologically active and periodically unstable 700 m high underwater escarpment located in the Gulf of Mexico that has been created by uplifting salt diapirs combined with sediment deposition. The site's geological history, soil permeability and clay shear strength characteristics govern current slope stability, and determine the timing of any future failure. The geological and geotechnical conditions are reported before presenting fully coupled, large-displacement numerical simulations employing critical state formulations of the slope's evolution over the last 600 000 years. The latter form the basis for strain-softening analyses of the pore pressure equalisation and progressive failure processes that control current slope stability. The analyses also address the ground movement patterns that precede instability, giving useful information for geohazard risk assessment and early warning monitoring system design.

Patients with mesial temporal lobe epilepsy (mTLE) show structural and functional abnormalities in hippocampus and surrounding mesial temporal structures. Brain signal complexity appears to be a marker of functional integrity or capacity. We examined complexity in 8 patients with intracranial hippocampal electrodes during performance of memory tasks (scene encoding and recognition) known to be sensitive to mesial temporal integrity. Our patients were shown to have right mesial temporal seizure onsets, permitting us to evaluate both epileptogenic (right) and healthy (left) hippocampi. Using multiscale entropy (MSE) as a measure of complexity, we found that iEEG from the epileptogenic hippocampus showed less complexity than iEEG from the healthy hippocampus. This difference was reliable for encoding but not for recognition. Our results indicate that both functional integrity and cognitive demands influence hippocampal signal complexity.

The composition of the essential oils of Achillea lingulata and A. umbellata were analysed by GC and GC-MS. Among the determined constituents, borneol, bornyl acetate, camphor, α- and β-thujone, and 1,8-cineol were found as the main components. Copyright © 2007 John Wiley & Sons, Ltd.

Introduction Studies of normal aging have shown age-related decreases in functional connectivity (FC) within the default mode network (DMN), particularly involving the posterior cingulate cortex (PCC). Although psychiatric conditions are common and underdiagnosed, none of these studies have combined psychiatric structured interview and neuropsychological evaluation to select the sample. Objectives to characterize age-related changes in PCC-FC connectivity in adults carefully screened to rule out neuropsychiatric disorders. Methods neuropsychiatric disorders were excluded by the Structured Clinical Interview for DSM-IV and neuropsychological evaluation. Restingstate functional MRI was acquired from 40, young, middle-age and elderly participants. After preprocessing, whole-brain, seed-based FC was estimated using a PCC seed. The relationship between age and PCC-FC was assessed using partial least squares. Results age was positively associated with PCC-FC in the left dorsolateral prefrontal cortex, bilateral supplementary motor area, right insula and left cerebellum; PCC-FC in these regions was negative or close to zero in young adults. PCC-FC of the medial part of the ventral prefrontal cortex was negatively associated with age; this region presented high positive PCC-FC in young adults (see figure). Conclusions age-related increases in PCC-FC were found in regions which are anti-correlated with the DMN, suggesting a decrease in the magnitude of anti-correlation. This may reflect a dedifferentiation process or weaker inter-network interactions. The careful sample selection prevents confounds related to neuropsychiatric disorders. Download : Download full-size image