“It’s a big deal, being given a person” – a study of the links between infertility and adoption

This study was commissioned and funded by Family Care and undertaken by Jo Ward and Joe Smeeton, both Principal Lecturers at Nottingham Trent University. It comprises a review of the literature relating to the links between adoption and infertility, a survey of the views of adoption from people who have experienced infertility, and 3 qualitative interviews with people who have experienced infertility but not adopted

Survival Probabilities at Spherical Frontiers

Motivated by tumor growth and spatial population genetics, we study the interplay between evolutionary and spatial dynamics at the surfaces of three-dimensional, spherical range expansions. We consider range expansion radii that grow with an arbitrary power-law in time: $R(t)=R_0(1+t/t^*)^{\Theta}$, where $\Theta$ is a growth exponent, $R_0$ is the initial radius, and $t^*$ is a characteristic time for the growth, to be affected by the inflating geometry. We vary the parameters $t^*$ and $\Theta$ to capture a variety of possible growth regimes. Guided by recent results for two-dimensional inflating range expansions, we identify key dimensionless parameters that describe the survival probability of a mutant cell with a small selective advantage arising at the population frontier. Using analytical techniques, we calculate this probability for arbitrary $\Theta$. We compare our results to simulations of linearly inflating expansions ($\Theta=1$ spherical Fisher-Kolmogorov-Petrovsky-Piscunov waves) and treadmilling populations ($\Theta=0$, with cells in the interior removed by apoptosis or a similar process). We find that mutations at linearly inflating fronts have survival probabilities enhanced by factors of 100 or more relative to mutations at treadmilling population frontiers. We also discuss the special properties of "marginally inflating" $(\Theta=1/2)$ expansions.Comment: 35 pages, 11 figures, revised versio

Using Surface-Motions for Locomotion of Microscopic Robots in Viscous Fluids

Microscopic robots could perform tasks with high spatial precision, such as acting in biological tissues on the scale of individual cells, provided they can reach precise locations. This paper evaluates the feasibility of in vivo locomotion for micron-size robots. Two appealing methods rely only on surface motions: steady tangential motion and small amplitude oscillations. These methods contrast with common microorganism propulsion based on flagella or cilia, which are more likely to damage nearby cells if used by robots made of stiff materials. The power potentially available to robots in tissue supports speeds ranging from one to hundreds of microns per second, over the range of viscosities found in biological tissue. We discuss design trade-offs among propulsion method, speed, power, shear forces and robot shape, and relate those choices to robot task requirements. This study shows that realizing such locomotion requires substantial improvements in fabrication capabilities and material properties over current technology.Comment: 14 figures and two Quicktime animations of the locomotion methods described in the paper, each showing one period of the motion over a time of 0.5 milliseconds; version 2 has minor clarifications and corrected typo

Spontaneous symmetry breaking in active droplets provides a generic route to motility

We explore a generic mechanism whereby a droplet of active matter acquires motility by the spontaneous breakdown of a discrete symmetry. The model we study offers a simple representation of a "cell extract" comprising, e.g., a droplet of actomyosin solution. (Such extracts are used experimentally to model the cytoskeleton.) Actomyosin is an active gel whose polarity describes the mean sense of alignment of actin fibres. In the absence of polymerization and depolymerization processes ('treadmilling'), the gel's dynamics arises solely from the contractile motion of myosin motors; this should be unchanged when polarity is inverted. Our results suggest that motility can arise in the absence of treadmilling, by spontaneous symmetry breaking (SSB) of polarity inversion symmetry. Adapting our model to wall-bound cells in two dimensions, we find that as wall friction is reduced, treadmilling-induced motility falls but SSB-mediated motility rises. The latter might therefore be crucial in three dimensions where frictional forces are likely to be modest. At a supra-cellular level, the same generic mechanism can impart motility to aggregates of non-motile but active bacteria; we show that SSB in this (extensile) case leads generically to rotational as well as translational motion.Comment: 13 pages, 8 figures, 1 tabl

Developments in information technology, networks and services

A review of policy issues facing Scotland as it faces changing from an industrial society to a knowledge led economy. Identifies the key developments, external trends and internal pressures which library policy makers face. Identifies content creation, metadata, preservation, user support as the four key areas

AN ECONOMIC EVALUATION OF COTTON AND PEANUT RESEARCH IN SOUTHEASTERN UNITED STATES

The purpose of this study was to utilize the economic surplus framework for evaluating the impact of investment in agricultural research. The economic impact measures used in this study were the total benefits and distribution of those benefits associated with investment in agricultural research. These results were used to calculate an internal rate of return on the investments. The focus of the research was on cotton and peanuts in the Southeast region of the United States. Two equations were estimated to determine the impacts of the money being spent on the research efforts of these two commodities. The results revealed positive benefits to consumers and producers exceeded the investment amount in each year for both commodities in the period. The total social benefits averaged about 201 million (1982) dollars annually for cotton research. Peanut research averaged about 191 million (1982) dollars resulting form research investment. The internal rates of return were 23.87 percent for cotton and 53.58 percent for peanuts, suggesting that past research investments produced a high return to society. This result does not conflict the results of other similar studies as those mentioned in the literature review.Research and Development/Tech Change/Emerging Technologies,

The cumulative effects of seven days of imposed exercise on energy balance and appetite regulation

A thesis submitted to the University of Bedfordshire, in fulfilment of the requirements for the degree of MSc by ResearchIncreasing energy expenditure (EE) through regular exercise is a promising strategy to prevent body fat gain. However, imposed exercise interventions often produce weight loss that is less than theoretically expected, possibility due to compensatory mechanisms in energy intake (EI) and EE. Study one was designed to determine whether a combined written and photographic food diary was a reliable measure of EI within a free-living environment across seven days. The results suggested this method was reliable at the group level. However, 95% limits of agreement (LoA) showed large variability (-1258 to 1545 kcal/day) at the individual level. Study two investigated acylated ghrelin, PYY and energy balance in response to 7-days of imposed exercise and a control condition. EI increased by 511 kcal/day in the exercise condition (P=0.005). Late-postprandial acylated ghrelin concentrations were higher in the exercise condition (P=0.072), but did not change from pre- to post intervention. There was a larger, but non-significant, increase in EI at the postprandial ad libitum pasta meal in the exercise condition (P=0.285). In conclusion, 7-days exercise resulted in increased EI under free-living conditions; similar results were found when assessed in a controlled laboratory environment. A larger sample size would allow confirmation of the findings