Visualising muscle anatomy using three-dimensional computer models - an example using the head and neck muscles of Sphenodon

We demonstrate how the computer-based technique of multi-body dynamics analysis (MDA) can be used to create schematic, but informative three-dimensional (3D) representations of complex muscle anatomy. As an example we provide an overview of the head and neck muscles present in Sphenodon (Diapsida: Lepidosauria: Rhynchocephalia). First a computer model based on micro-computed tomography datasets provides a detailed and anatomically correct three-dimensional (3D) framework to work from. Secondly, muscles are represented by groups of cylinders that can be colour coded as desired. This allows muscle positions, attachment areas, and 3D orientation to be visualised clearly. This method has advantages over imaging techniques such as two-dimensional drawings and permits the form and function of the muscles to be understood in a way that is not always possible with more classical visualisation techniques. Copyright: Palaeontological Association December 2009

The head and neck muscles associated with feeding in sphenodon (Reptilia: Lepidosauria: Rhynchocephalia)

Feeding in Sphenodon, the tuatara of New Zealand, is of interest for several rea-sons. First, the modern animal is threatened by extinction, and some populations are in competition for food with Pacific rats. Second, Sphenodon demonstrates a feeding apparatus that is unique to living amniotes: an enlarged palatine tooth row, acrodont dentition, enlarged incisor-like teeth on the premaxilla, a posterior extension of the dentary and an elongate articular surtace that permits prooral shearing. Third, Spheno-don has a skull with two complete lateral temporal bars and is therefore structurally analogous to the configuration hypothesised for the ancestral diapsid reptile. Further-more, the fossil relatives of Sphenodon demonstrate considerable variation in terms of feeding apparatus and skull shape. Lastly, as Sphenodon is the only extant rhyn-chocephalian it represents a potentially useful reference taxon for both muscle recon-struction in extinct reptile taxa and determination of muscle homology in extant taxa. Here we provide an up-to-date consensus view of osteology and musculature in Sphenodon that is relevant to feeding. Discrepancies within previous descriptions are evaluated and synthesised with new observations. This paper displays the complex muscle arrangement using a range of different imaging techniques and a variety of different angles. This includes photographs, illustrations, schematic diagrams, and microcomputed tomography (micro-CT) slice images. © Palaeontological Association August 2009

Laws relating runs, long runs, and steps in gambler's ruin, with persistence in two strata

Define a certain gambler's ruin process \mathbf{X}_{j}, \mbox{ \ }j\ge 0, such that the increments $\varepsilon_{j}:=\mathbf{X}_{j}-\mathbf{X}_{j-1}$ take values $\pm1$ and satisfy $P(\varepsilon_{j+1}=1|\varepsilon_{j}=1, |\mathbf{X}_{j}|=k)=P(\varepsilon_{j+1}=-1|\varepsilon_{j}=-1,|\mathbf{X}_{j}|=k)=a_k$, all $j\ge 1$, where $a_k=a$ if $0\le k\le f-1$, and $a_k=b$ if $f\le k<N$. Here $0<a, b <1$ denote persistence parameters and $f ,N\in \mathbb{N}$ with $f<N$. The process starts at $\mathbf{X}_0=m\in (-N,N)$ and terminates when $|\mathbf{X}_j|=N$. Denote by ${\cal R}'_N$, ${\cal U}'_N$, and ${\cal L}'_N$, respectively, the numbers of runs, long runs, and steps in the meander portion of the gambler's ruin process. Define $X_N:=\left ({\cal L}'_N-\frac{1-a-b}{(1-a)(1-b)}{\cal R}'_N-\frac{1}{(1-a)(1-b)}{\cal U}'_N\right )/N$ and let $f\sim\eta N$ for some $0<\eta <1$. We show $\lim_{N\to\infty} E\{e^{itX_N}\}=\hat{\varphi}(t)$ exists in an explicit form. We obtain a companion theorem for the last visit portion of the gambler's ruin.Comment: Presented at 8th International Conference on Lattice Path Combinatorics, Cal Poly Pomona, Aug., 2015. The 2nd version has been streamlined, with references added, including reference to a companion document with details of calculations via Mathematica. The 3rd version has 2 new figures and improved presentatio

Entomological surveillance following a long-lasting insecticidal net universal coverage campaign in Midwestern Uganda.

BACKGROUND: A universal coverage campaign (UCC) with long-lasting insecticidal nets (LLINs) was implemented in four districts in Midwestern Uganda in 2009-2010. Entomological surveys were carried out to monitor changes in vector density, behaviour and malaria transmission following this intervention. METHODS: Anopheles mosquitoes were collected using CDC light traps quarterly and human landing catch twice a year in four sites. Collections were done at baseline before the campaign and over a three-year period following the campaign. Plasmodium falciparum circumsporozoite enzyme-linked immunosorbent assays were performed. A subset of anophelines were molecularly identified to species, and kdr L1014S frequencies were determined. RESULTS: The prevailing malaria vector in three sites was Anopheles gambiae s.l. (>97 %), with An. funestus s.l. being present in low numbers only. An. gambiae s.s. dominated (> 95 %) over An. arabiensis within A. gambiae s.l. In the remaining site, all three vector species were observed, although their relative densities varied among seasons and years. Vector densities were low in the year following the UCC but increased over time. Vector infectivity was 3.2 % at baseline and 1.8 % three years post-distribution (p = 0.001). The daily entomological inoculation rate (EIR) in 2012 varied between 0.0-0.98 for the different sites compared to a baseline EIR that was between 0.0-5.8 in 2009. There was no indication of a change in indoor feeding times, and both An. gambiae s.l. and An. funestus s.l. continued to feed primarily after midnight with vectors being active until the early morning. Kdr L1014S frequencies were already high at baseline (53-85 %) but increased significantly in all sites over time. CONCLUSIONS: The entomological surveys indicate that there was a reduction in transmission intensity coinciding with an increase in use of LLINs and other antimalarial interventions in areas of high malaria transmission. There was no change in feeding behaviour, and human-vector contact occurred indoors and primarily after midnight constantly throughout the study. Although the study was not designed to evaluate the effectiveness of the intervention compared to areas with no such intervention, the reduction in transmission occurred in an area with previously stable malaria, which seems to indicate a substantial contribution of the increased LLIN coverage

Redistributed Manufacturing and the Impact of Big Data: A Consumer Goods Perspective

Digitalisation and the growth of big data promise greater customisation as well as change in how manufacturing is distributed. Yet, challenges arise in applying these new approaches in consumer goods industries that often emphasise mass production and extended supply chains. We build a conceptual framework to explore whether big data combined with new manufacturing technologies can facilitate redistributed manufacturing. Through analysis of 24 consumer goods industry cases using primary and secondary data, we investigate evolving manufacturing configurations, their underlying drivers, the role of big data applications, and their impact on the redistribution of manufacturing. We find some applications of redistributed manufacturing concepts, although in other cases existing manufacturing configurations are leveraged for high volume consumer goods products through big data analytics and market segmentation. The analysis indicates that the framework put forward in the paper has broader value in organising thinking about emerging interrelationships between big data and manufacturing.The work was supported by the Engineering and Physical Sciences Research Council (EPSRC) and the Economic and Social Research Council (ESRC) through The Network in Consumer Goods, Big Data and Re-Distributed Manufacturing (RECODE) hosted at Cranfield University under grant number EP/M017567/1

Matrix interpretation of multiple orthogonality

In this work we give an interpretation of a (s(d + 1) + 1)-term recurrence relation in terms of type II multiple orthogonal polynomials.We rewrite this recurrence relation in matrix form and we obtain a three-term recurrence relation for vector polynomials with matrix coefficients. We present a matrix interpretation of the type II multi-orthogonality conditions.We state a Favard type theorem and the expression for the resolvent function associated to the vector of linear functionals. Finally a reinterpretation of the type II Hermite- Padé approximation in matrix form is given

Transition probabilities for general birth-death processes with applications in ecology, genetics, and evolution

A birth-death process is a continuous-time Markov chain that counts the number of particles in a system over time. In the general process with $n$ current particles, a new particle is born with instantaneous rate $\lambda_n$ and a particle dies with instantaneous rate $\mu_n$. Currently no robust and efficient method exists to evaluate the finite-time transition probabilities in a general birth-death process with arbitrary birth and death rates. In this paper, we first revisit the theory of continued fractions to obtain expressions for the Laplace transforms of these transition probabilities and make explicit an important derivation connecting transition probabilities and continued fractions. We then develop an efficient algorithm for computing these probabilities that analyzes the error associated with approximations in the method. We demonstrate that this error-controlled method agrees with known solutions and outperforms previous approaches to computing these probabilities. Finally, we apply our novel method to several important problems in ecology, evolution, and genetics

The impact of Stieltjes' work on continued fractions and orthogonal polynomials

Stieltjes' work on continued fractions and the orthogonal polynomials related to continued fraction expansions is summarized and an attempt is made to describe the influence of Stieltjes' ideas and work in research done after his death, with an emphasis on the theory of orthogonal polynomials