Faecal sludge simulants to aid the development of desludging technologies

This paper presents a review of currently available data from the literature on the undrained shear strength, bulk density, stickiness and debris content of faecal sludge. Those data have been used to develop two different simulants that replicate the full range of shear strengths and densities reported for faecal sludge. Comprehensive specifications are also presented for the debris or solid waste found in latrines to more closely replicate the challenge of pumping faecal sludge. Finally, a design guide has been produced to capture these results and support quantitative performance testing of desludging pumps. The simulants have already been used as part of the Bill &amp; Melinda Gates Foundation's Faecal Sludge Omni-Ingestor project and by Water for People's SaniHub in developing improved desludging pumps. The wider use of these simulants could accelerate the development of pit emptying technologies and help standardize the quantitative evaluation of their performance.</jats:p

A stochastic model for the evolution of the web allowing link deletion

Recently several authors have proposed stochastic evolutionary models for the growth of the web graph and other networks that give rise to power-law distributions. These models are based on the notion of preferential attachment leading to the ``rich get richer'' phenomenon. We present a generalisation of the basic model by allowing deletion of individual links and show that it also gives rise to a power-law distribution. We derive the mean-field equations for this stochastic model and show that by examining a snapshot of the distribution at the steady state of the model, we are able to tell whether any link deletion has taken place and estimate the link deletion probability. Our model enables us to gain some insight into the distribution of inlinks in the web graph, in particular it suggests a power-law exponent of approximately 2.15 rather than the widely published exponent of 2.1

Lebensqualität von Brustkrebspatientinnen bei offener und verschlossener Reaktion auf ein Gesprächs- und Informationsangebot

Da sich die Voraussetzungen in der Nachsorge von Patientinnen mit Brustkrebs im letzten Jahrzehnt verändert haben, wird im Theorieteil der Arbeit auf das Konzept Lebensqualität, die Krankheit Brustkrebs selbst, die aktuellen Nachsorgebedingungen und auf Coping eingegangen. Im Anschluß erfolgt die Darstellung der Ergebnisse von 204 Patientinnen, die zwischen 1996 und 1998 an einem neu diagnostizierten Mammakarzinom erkrankt und operiert worden sind. Die Daten wurden bezüglich der Lebensqualität in der Nachsorgeperiode von einem Jahr ausgewertet. Als Meßinstrument wurde der Quality of Life Questionnaire der EORTC benutzt. Es zeigt sich, daß sich für alle Patientinnen die Lebensqualität im Verlauf von einem Jahr signifikant erhöht. Die Patientinnen, die eine offene Haltung bezüglich eines Informations- und Gesprächsangebots zeigen (n=43), haben zum Zeitpunkt der Klinikentlassung und nach 12 Monaten eine signifikant schlechtere globale Lebensqualität als die verschlossenen Patientinnen (n=12). Die bezüglich des Gesprächs- und Informationsangebots indifferenten Patientinnen (n=149) nehmen einen Mittelplatz ein. Als weiteres Ergebnis zeigt sich ein signifikanter Unterschied zwischen der Selbsteinschätzung der Lebensqualität durch die Patientinnen und der Fremdeinschätzung der Lebensqualität durch die Interviewführenden. Die Patientinnen schätzen ihre globale Lebensqualität signifikant schlechter ein (Mittelwert: 58), als dies in der Fremdeinschätzung durch die Interviewführenden der Fall ist (Mittelwert: 63,2).Die Ergebnisse könnten darauf hindeuten, daß die Offenheit der Patientinnen aus einer inneren Not heraus besteht, während die verschlossenen Patientinnen durch die größere Distanz zum Thema Brustkrebs von einer höheren Lebensqualität profitieren. Die in der Literatur referierten Ergebnisse bezüglich der Selbst- und Fremdeinschätzung der Lebensqualität finden in dieser Studie keine Bestätigung. Es wird deutlich, daß es in der Nachsorge unterschiedliche Reaktionen mit Auswirkung auf die Lebensqualität der Patientinnen gibt; eine Forschungsvertiefung wäre für die bessere Kenntnis der psychosozialen Situation der Patientinnen und nachfolgend für eine Verbesserung der Nachsorge im Sinne der aktuellen Leitlinien wünschenswert

Simulation of oscillopsia in virtual reality

Purpose: Nystagmus is characterised by involuntary eye movement. A proportion of those with nystagmus experience the world constantly in motion as their eyes move: a symptom known as oscillopsia. Individuals with oscillopsia can be incapacitated and often feel neglected due to limited treatment options. Effective communication of the condition is challenging and no tools to aid communication exist. This paper describes a virtual reality (VR) application that recreates the effects of oscillopsia, enabling others to appreciate the condition. Methods: Eye tracking data was incorporated into a VR oscillopsia simulator and released as a smartphone app – “Nystagmus Oscillopsia Sim VR”. When a smartphone is used in conjunction with a Google Cardboard headset, it presents an erratic image consistent with oscillopsia. The oscillopsia simulation was appraised by six participants for its representativeness. These individuals have nystagmus and had previously experienced oscillopsia but were not currently symptomatic; they were therefore uniquely placed to judge the app. The participants filled in a questionnaire to record impressions and the usefulness of the app. Results: The published app has been downloaded ~3700 times (28/02/2018) and received positive feedback from the nystagmus community. The validation study questionnaire scored the accuracy of the simulation an average of 7.8/10 while its ability to aid communication received 9.2/10. Conclusion: The evidence indicates that the simulation can effectively recreate the sensation of oscillopsia and facilitate effective communication of the symptoms associated with the condition. This has implications for communication of other visual conditions

Quantum Weakly Nondeterministic Communication Complexity

We study the weakest model of quantum nondeterminism in which a classical proof has to be checked with probability one by a quantum protocol. We show the first separation between classical nondeterministic communication complexity and this model of quantum nondeterministic communication complexity for a total function. This separation is quadratic.Comment: 12 pages. v3: minor correction

A stochastic evolutionary model for capturing human dynamics

The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in various contexts. Here we propose a generative model to capture the dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. We derive a general solution for the model in the form of a product, and then a continuous approximation to the solution via the renewal equation describing age-structured population dynamics. This enables us to model a wide range of survival distributions, according to the choice of the mortality distribution. We provide empirical evidence for the validity of the model from a longitudinal data set of popular search engine queries over 114 months, showing that the survival function of these queries is closely matched by the solution for our model with power-law mortality

A quantum search for zeros of polynomials

A quantum mechanical search procedure to determine the real zeros of a polynomial is introduced. It is based on the construction of a spin observable whose eigenvalues coincide with the zeros of the polynomial. Subsequent quantum mechanical measurements of the observable output directly the numerical values of the zeros. Performing the measurements is the only computational resource involved

A Novel Diagnostic Aid for Detection of Intra-Abdominal Adhesions to the Anterior Abdominal Wall Using Dynamic Magnetic Resonance Imaging

Introduction. Abdominal adhesions can cause serious morbidity and complicate subsequent operations. Their diagnosis is often one of exclusion due to a lack of a reliable, non-invasive diagnostic technique. Development and testing of a candidate technique are described below. Method. During respiration, smooth visceral sliding motion occurs between the abdominal contents and the walls of the abdominal cavity. We describe a technique involving image segmentation and registration to calculate shear as an analogue for visceral slide based on the tracking of structures throughout the respiratory cycle. The presence of an adhesion is attributed to a resistance to visceral slide resulting in a discernible reduction in shear. The abdominal movement due to respiration is captured in sagittal dynamic MR images. Results. Clinical images were selected for analysis, including a patient with a surgically confirmed adhesion. Discernible reduction in shear was observed at the location of the adhesion while a consistent, gradually changing shear was observed in the healthy volunteers. Conclusion. The technique and its validation show encouraging results for adhesion detection but a larger study is now required to confirm its potential