Quantification of slope displacement rates using acoustic emission monitoring

In soil slopes, developing shear surfaces generate acoustic emission (AE). The Authors have previously proposed the use of active waveguides for monitoring the stability of such slopes. Active waveguides comprise of a steel tube installed in a preformed borehole through a slope with coarse grained soil backfill placed in the annulus around the tube. Deformation of the host soil generates AE in the active waveguide. Field trials of this system reported previously have shown that AE rates are linked to slope deformation rates. This paper extends the study by detailing a method for quantifying slope movement rates using an active waveguide. A series of laboratory experiments are presented and used to define the relationship between AE event count rate and displacement rate. The method was shown to differentiate rates within an order of magnitude, which is consistent with standard landslide movement classification (i.e. 1 to 0.001 mm per minute), using a relationship derived between the gradient of the event count rate with time and deformation rate. In addition, it was possible to detect a change in displacement rate within two minutes of it occurring even at very slow rates (i.e. 0.0018mm/min). Knowledge of changes in displacement rate is important in situations where slope movements are suddenly triggered or displacements accelerate in response to a destabilising event. Field trials of a realtime AE monitoring system are currently in progress to compare performance against traditional instrumentation

Landslide hazard evaluation by means of several monitoring techniques, including an acoustic emission sensor

At Passo della Morte in the Italian Eastern Alps a geomorphological survey has identified potential instability of the valley side slope that could result in a debris/rock avalanche, which would threaten the Tagliamento River. A nationally important road passes through a tunnel 130 m long behind the potentially unstable slope. The stratum comprises a sequence of Limestone layers, dipping in the slope direction towards the river. Although currently there is no clear evidence of movement, the geological setting indicates a predisposition to instability that could involve a large landslide and extremely fast deformations can be foreseen. To appraise the physical characteristics of the rock mass and to provide an early warning of instability, monitoring instrumentation has been installed and monitored since late 2010. Extensometers, MEMS, TDR cables, a ver-tical inclinometer, a seismic station to monitor Limestone rock mass deformation generated micro-tremors and an acoustic emission (AE) monitoring system have been installed. The instruments are connected to real-time recording and transmitting units. The paper describes the geological setting and associated potential modes of instability. It details the design of the instrument installations and presents results obtained to date. In particular, the novel acoustic emission monitoring approach is described including sensor design, method of operation and comparison of the measured AE response with the deformation measurements and detected micro-tremor trends. Initial results indicate a strong response of the acoustic sensors to rainfall events. No sig-nificant rock mass deformations have been detected at depth within the slope to date, although a surface ex-tensometer has shown widening of a bedding tension crack. Upgrading of the instrumentation system is ongo-ing and it is planned to continue monitoring for the foreseeable future

Field trial of an acoustic emission early warning system for slope instability

Slope failures world-wide cause many thousands of deaths each year and damage built environment infrastructure costing billions of pounds to repair, resulting in thousands of people being made homeless and the breakdown of basic services such as water supply and transport. There is a clear need for low cost instrumentation that can provide an early warning of slope instability to enable evacuation of vulnerable people and timely repair and maintenance of critical infrastructure. Current instrumentation systems are either too expensive for wide scale use or have technical limitations. An approach, Assessment of Landslides using Acoustic Real-time Monitoring Systems (ALARMS), has been developed and demonstrated through research. An approach developed using measurement of acoustic emission generated during the onset of slope failure to provide quantitative information on slope displacement is described. Sensor operation, deployment strategy, laboratory validation and field performance is considered. The paper presents the results of a field trial of acoustic sensors on an active landslide at Hollin Hill, North Yorkshire, and introduces additional ongoing tri-als in the UK and Italy. Real-time monitoring of acoustic emission generated by the deforming slope has been compared to traditional inclinometer slope displacement measurements. Analysis of the results of the field trial has established that there is a direct relationship between AE and displacement rate trends triggered by rainfall events. Slope deformation events have a characteristic ‘S’ shaped cumulative AE vs. time relationship indicating initial acceleration followed by deceleration of the slide body

Synthesizing diverse evidence: the use of primary qualitative data analysis methods and logic models in public health reviews

Objectives: The nature of public health evidence presents challenges for conventional systematic review processes, with increasing recognition of the need to include a broader range of work including observational studies and qualitative research, yet with methods to combine diverse sources remaining underdeveloped. The objective of this paper is to report the application of a new approach for review of evidence in the public health sphere. The method enables a diverse range of evidence types to be synthesized in order to examine potential relationships between a public health environment and outcomes. Study design: The study drew on previous work by the National Institute for Health and Clinical Excellence on conceptual frameworks. It applied and further extended this work to the synthesis of evidence relating to one particular public health area: the enhancement of employee mental well-being in the workplace. Methods: The approach utilized thematic analysis techniques from primary research, together with conceptual modelling, to explore potential relationships between factors and outcomes. Results: The method enabled a logic framework to be built from a diverse document set that illustrates how elements and associations between elements may impact on the well-being of employees. Conclusions: Whilst recognizing potential criticisms of the approach, it is suggested that logic models can be a useful way of examining the complexity of relationships between factors and outcomes in public health, and of highlighting potential areas for interventions and further research. The use of techniques from primary qualitative research may also be helpful in synthesizing diverse document types. (C) 2010 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved

Development of a low cost acoustic emission early warning system for slope instability

Slope failures world-wide cause many thousands of deaths each year and damage built environment infrastructure. There is a clear need for low cost instrumentation that can provide an early warning of slope instability to enable evacuation of vulnerable people and timely repair and maintenance of critical infrastructure. Current instrumentation systems are either too expensive for wide scale use or have technical limitations. An approach, Assessment of Landslides using Acoustic Real-time Monitoring Systems (ALARMS), has been developed and demonstrated through research. An approach has been developed using measurement of acoustic emission generated during the onset of slope failure to provide quantitative information on slope displacement rates. Research is in progress to develop low cost acoustic sensors. A unitary acoustic emission slope displacement rate sensor has been designed and is being trialled in an active landslide. Continuous monitored acoustic emission rates show comparable trends to displacement rates measured using an inclinometer. Acoustic emission increase after rainfall events and this is considered to indicate increased displacement rates

On the Relationship between the Uniqueness of the Moonshine Module and Monstrous Moonshine

We consider the relationship between the conjectured uniqueness of the Moonshine Module, ${\cal V}^\natural$, and Monstrous Moonshine, the genus zero property of the modular invariance group for each Monster group Thompson series. We first discuss a family of possible $Z_n$ meromorphic orbifold constructions of ${\cal V}^\natural$ based on automorphisms of the Leech lattice compactified bosonic string. We reproduce the Thompson series for all 51 non-Fricke classes of the Monster group $M$ together with a new relationship between the centralisers of these classes and 51 corresponding Conway group centralisers (generalising a well-known relationship for 5 such classes). Assuming that ${\cal V}^\natural$ is unique, we then consider meromorphic orbifoldings of ${\cal V}^\natural$ and show that Monstrous Moonshine holds if and only if the only meromorphic orbifoldings of ${\cal V}^\natural$ give ${\cal V}^\natural$ itself or the Leech theory. This constraint on the meromorphic orbifoldings of ${\cal V}^\natural$ therefore relates Monstrous Moonshine to the uniqueness of ${\cal V}^\natural$ in a new way.Comment: 53 pages, PlainTex, DIAS-STP-93-0

The splicing landscape is globally reprogrammed during male meiosis

Meiosis requires conserved transcriptional changes, but it is not known whether there is a corresponding set of RNA splicing switches. Here, we used RNAseq of mouse testis to identify changes associated with the progression from mitotic spermatogonia to meiotic spermatocytes. We identified ∼150 splicing switches, most of which affect conserved protein-coding exons. The expression of many key splicing regulators changed in the course of meiosis, including downregulation of polypyrimidine tract binding protein (PTBP1) and heterogeneous nuclear RNP A1, and upregulation of nPTB, Tra2β, muscleblind, CELF proteins, Sam68 and T-STAR. The sequences near the regulated exons were significantly enriched in target sites for PTB, Tra2β and STAR proteins. Reporter minigene experiments investigating representative exons in transfected cells showed that PTB binding sites were critical for splicing of a cassette exon in the Ralgps2 mRNA and a shift in alternative 5′ splice site usage in the Bptf mRNA. We speculate that nPTB might functionally replace PTBP1 during meiosis for some target exons, with changes in the expression of other splicing factors helping to establish meiotic splicing patterns. Our data suggest that there are substantial changes in the determinants and patterns of alternative splicing in the mitotic-to-meiotic transition of the germ cell cycle

Temperature-dependent development of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and its larval parasitoid, Habrobracon hebetor (Say) (Hymenoptera: Braconidae): implications for species interactions

Habrobracon hebetor (Say) is a parasitoid of various Lepidoptera including Helicoverpa armigera (Hübner), a key pest of different crops and vegetables. The development of both H. armigera and H. hebetor were simultaneously evaluated against a wide range of constant temperatures (10, 15, 17.5, 20, 25, 27.5, 30, 35, 37.5 and 40 °C). Helicoverpa armigera completed its development from egg to adult within a temperature range of 17.5–37.5 °C and H. hebetor completed its life cycle from egg to adult within a temperature range of 15–40 °C. Based on the Ikemoto and Takai model the developmental threshold (T o) and thermal constant (K) to complete the immature stages, of H. armigera were calculated as 11.6 °C and 513.6 DD, respectively, and 13 °C and 148 DD, respectively, for H. hebetor. Analytis/Briere-2 and Analytis/Briere-1 were adjudged the best non-linear models for prediction of phenology of H. armigera and H. hebetor, respectively and enabled estimation of the optimum (T opt) and maximum temperature (T max) for development with values of 34.8, 38.7, 36.3, and 43 °C for host and the parasitoid, respectively. Parasitisation by H. hebetor was maximal at 25 °C but occurred even at 40 °C. This study suggests although high temperature is limiting to insects, our estimates of the upper thermal limits for both species are higher than previously estimated. Some biological control of H. armigera by H. hebetor may persist in tropical areas, even with increasing temperatures due to climate change

Spin chains with dynamical lattice supersymmetry

Spin chains with exact supersymmetry on finite one-dimensional lattices are considered. The supercharges are nilpotent operators on the lattice of dynamical nature: they change the number of sites. A local criterion for the nilpotency on periodic lattices is formulated. Any of its solutions leads to a supersymmetric spin chain. It is shown that a class of special solutions at arbitrary spin gives the lattice equivalents of the N=(2,2) superconformal minimal models. The case of spin one is investigated in detail: in particular, it is shown that the Fateev-Zamolodchikov chain and its off-critical extension admits a lattice supersymmetry for all its coupling constants. Its supersymmetry singlets are thoroughly analysed, and a relation between their components and the weighted enumeration of alternating sign matrices is conjectured.Comment: Revised version, 52 pages, 2 figure