Genetic heterogeneity of residual variance in broiler chickens

Aims were to estimate the extent of genetic heterogeneity in environmental variance. Data comprised 99 535 records of 35-day body weights from broiler chickens reared in a controlled environment. Residual variance within dam families was estimated using ASREML, after fitting fixed effects such as genetic groups and hatches, for each of 377 genetically contemporary sires with a large number of progeny ($>$100 males or females each). Residual variance was computed separately for male and female offspring, and after correction for sampling, strong evidence for heterogeneity was found, the standard deviation between sires in within variance amounting to 15–18% of its mean. Reanalysis using log-transformed data gave similar results, and elimination of 2–3% of outlier data reduced the heterogeneity but it was still over 10%. The correlation between estimates for males and females was low, however. The correlation between sire effects on progeny mean and residual variance for body weight was small and negative (-0.1). Using a data set bigger than any yet presented and on a trait measurable in both sexes, this study has shown evidence for heterogeneity in the residual variance, which could not be explained by segregation of major genes unless very few determined the trait

Working the crowd : improvisational entrepreneurship and equity crowdfunding in nascent entrepreneurial ventures

Equity crowdfunding has rapidly established itself as an important part of the funding landscape for nascent entrepreneurial ventures. To date, however, little is known about the nature of the demand for equity crowdfunding or its impact on recipient firms. This paper draws on an interview-based study of entrepreneurs in 42 equity crowdfunded start-ups in the UK. The study found strong demand for this funding from these experimental and improvisational entrepreneurs within innovative, consumer-focused, early stage firms. Many entrepreneurs were classic “discouraged borrowers” attracted by the ability to obtain finance quickly with relatively little diminution of their equity or autonomy. In terms of impact, equity crowdfunding seems to confer important intangible benefits to investee companies which amount to more than money. Given their strongly improvisational nature, the concept of entrepreneurial bricolage seems a suitable theoretical lens explicating the behavioural aspects of the entrepreneurs examined.PostprintPeer reviewe

Start-ups, entrepreneurial networks and equity crowdfunding : a processual perspective

This paper outlines findings from a large-scale interview based study of start-ups who obtained equity crowdfunding in the UK. It takes a novel integrative approach towards the analysis of entrepreneurial networks by examining both personal and business networks involved in the equity crowdfunding process. Adopting a processual perspective, the empirical findings show that networks and social capital play a critical role in the crowdfunding process. Start-ups leverage, build and draw upon a complex array of network actors and 'ties' as they move through the different stages of their crowdfunding journey. The paper shows that this form of funding confers important relational benefits to recipients which amount to 'more than money'. It concludes that equity crowdfunding is a highly 'relational' form of entrepreneurial finance, requiring holistic forms of empirical investigation. Implications for theoretical development, managerial practice and further research are outlined.PostprintPeer reviewe

Collaborations for First-Year Student Engagement: From Ideas to Assessment

Extensive research has proven the value of programs and courses, such as those at our university, that assist first-year students in their transition to college. Recently our university has attempted to bring our initiatives to the next level, ensuring that they are customized for our students and that they achieve the institutional goals of retention, connection, persistence, and, most important, engagement. Presenters from student affairs and academic affairs will discuss these initiatives, the cross-divisional collaboration that has created and sustained them, and the steps, based on course-design principles, that we are taking to foster greater coordination and build in ongoing assessment. This session will be of interest to all who teach, advise, and otherwise support first-year students; participants will discuss and practice techniques to improve collaboration and to generate learning outcomes for first-year initiatives, whether inside or outside the classroom

QTL mapping technology using variance components in general pedigrees applied to the poultry industry

The subject area for this thesis is detection of chromosomal regions or QTL causing complex variation at the phenotypic level. In particular, the differentiation of sources of additive and non additive variation. Unlike QTL mapping using divergent or inbred lines, this study aims to explore methods within populations, facilitating direct application of techniques such as marker assisted selection. Specifically, objectives were to evaluate a linear model or variance components (VC) approach to explore the existence and magnitude of variation caused by additive, dominant and imprinted QTL segregating in general pedigrees. This has been achieved by combining extensive simulation and analysis of real commercial poultry data. Linear models were constructed to simultaneously estimate fixed, polygenic and QTL effects. Different genetic models were compared by hierarchical extension to incorporate more variance components, and likelihood ratio test statistics derived from the comparison of full with reduced or null models. A range of additive, dominant and imprinted QTL effects were simulated within two-generation poultry, pig and human type pedigrees. Effects of family size and structure on power, accuracy of variance component estimation, and distribution of the test statistic, were evaluated. Empirical thresholds were derived by simulating populations under the null hypotheses for each type of simulated pedigree and permutation analysis in real data. In the commercial poultry data, dominant and imprinted QTL effects were found for bodyweight and conformation score. Under simulation, although power to detect QTL effects was high in two-generation livestock pedigrees, considerable variation was found in power and behaviour of test statistics. Power to detect dominance was greater in pig and poultry than human type pedigrees with theoretical thresholds increasingly conservative as the number of dams per sire decreased, highlighting the need for empirical derivation of the critical test statistic. The detection of variance caused by imprinted genes and in particular estimates of variance components were also heavily dependent upon the number of sire and dam families used to estimate them. Results showed that VC analysis can be used to routinely detect genetic effects including imprinting and dominance in complex pedigrees. The work presented is the most extensive evaluation of the detection of non additive QTL using VC methods to date. Results challenge standard assumptions made about power and null distributions and show that optimal use of methodology is dependent on pedigree structure

Looking inside the ‘black box’ of digital firm scaling : an ethnographically informed conceptualisation

Funding: British Academy (grant number SRG/170550).In recent years there has been an upsurge of interest in firm scaling. Owing to the fact our conceptual and theoretical grasp of this phenomenon remains under-developed, this paper offers a novel conceptualisation of the scaling process based on an in-depth ethnographic study of a London-based digital Fintech. Scaling involves deliberately enacting and surmounting a series of managerial challenges such as human capital re-positioning, business model reconfiguration, customer acquisition and the acquisition of external growth capital. Our theoretical contribution views the micro-foundations of scaling as a distinctive relational process-based phenomenon. Under the conceptual framework posited, entrepreneurial human capital and successful scaling are inextricably interwoven. Entrepreneurial founders and managers are pivotal for orchestrating scaling and our conceptualisation builds upon the trigger point model of firm development, which reinforces the primacy of entrepreneurial agency for optimising growth triggers.Peer reviewe

Method for Quantitative Study of Airway Functional Microanatomy Using Micro-Optical Coherence Tomography

We demonstrate the use of a high resolution form of optical coherence tomography, termed micro-OCT (μOCT), for investigating the functional microanatomy of airway epithelia. μOCT captures several key parameters governing the function of the airway surface (airway surface liquid depth, periciliary liquid depth, ciliary function including beat frequency, and mucociliary transport rate) from the same series of images and without exogenous particles or labels, enabling non-invasive study of dynamic phenomena. Additionally, the high resolution of μOCT reveals distinguishable phases of the ciliary stroke pattern and glandular extrusion. Images and functional measurements from primary human bronchial epithelial cell cultures and excised tissue are presented and compared with measurements using existing gold standard methods. Active secretion from mucus glands in tissue, a key parameter of epithelial function, was also observed and quantified