Shorter juvenile telomere length is associated with higher survival to spawning in migratory Atlantic salmon

The risk of mortality associated with a long-distance migration will depend on an animal's physiological state, as well as the prevailing ecological conditions. Here we assess whether juvenile telomere length, which in endotherms has been shown to be a biomarker of physiological state and expected lifespan, predicts whether wild Atlantic salmon Salmo salar successfully complete their marine migration. Over 1800 juvenile fish were trapped, measured, PIT-tagged and a tissue biopsy taken when migrating as juveniles down-river towards the sea. Survivors of the marine phase of the life cycle were then re-trapped and re-sampled when returning to the river to spawn as sexually mature adults, 1.5-2.5 years later. Most individuals experienced a reduction in telomere length during the marine migratory phase of their life cycle. While the relative rate of telomere loss was greater in males than females, telomere loss was unrelated to growth at sea. Contrary to expectations, salmon that had the shortest telomeres at the time of the outward migration had the greatest probability of surviving through to the return migration. This effect, independent of body size, may indicate a trade-off between investment in readiness for marine life (which favours high glucocorticoid levels, known to increase telomere attrition in other vertebrate species) and investment in telomere maintenance. Survival was also significantly influenced by the seasonal timing of outward migration, with the fish migrating downstream earliest in the spring having the highest probability of return. This study reveals that telomere length is associated with survival, although in ways that contrast with patterns seen in endotherms. This illustrates that while telomeres may be universally important for chromosome protection, the potential for telomere dynamics to predict performance may vary across taxa

Links between parental life histories of wild salmon and the telomere lengths of their offspring

The importance of parental contributions to offspring development and subsequent performance is self-evident at a genomic level; however, parents can also affect offspring fitness by indirect genetic and environmental routes. The life history strategy that an individual adopts will be influenced by both genes and environment; and this may have important consequences for offspring. Recent research has linked telomere dynamics (i.e. telomere length and loss) in early life to future viability and longevity. Moreover, a number of studies have reported a heritable component to telomere length across a range of vertebrates, though the effects of other parental contribution pathways have been far less studied. By using wild Atlantic salmon with different parental life histories in an experimental split-brood IVF mating design and rearing the resulting families under standardised conditions, we show that there can be significant links between parental life history and offspring telomere length (studied at the embryo and fry stage). Maternal life history traits, in particular egg size, were most strongly related to offspring telomere length at the embryonic stage, but then became weaker through development. In contrast, paternal life history traits, such as the father's growth rate in early life, had a greater association in the later stages of offspring development. However, offspring telomere length was not significantly related to either maternal or paternal age at reproduction, nor to paternal sperm telomere length. This study demonstrates both the complexity and the importance of parental factors that can influence telomere length in early life

Sustaining entrepreneurial business: a complexity perspective on processes that produce emergent practice

This article examines the management practices in an entrepreneurial small firm which sustain the business. Using a longitudinal qualitative case study, four general processes are identified (experimentation, reflexivity, organising and sensing), that together provide a mechanism to sustain the enterprise. The analysis draws on concepts from entrepreneurship and complexity science. We suggest that an entrepreneur’s awareness of the role of these parallel processes will facilitate their approaches to sustaining and developing enterprises. We also suggest that these processes operate in parallel at multiple levels, including the self, the business and inter-firm networks. This finding contributes to a general theory of entrepreneurship. A number of areas for further research are discussed arising from this result

The Permian Geology, Physiography and Landscape Evolution of Northeastern Victoria

Northeast Victorian diamictites (tillites) and interstratified traction deposits (fluvioglacials), now mapped in detail and interpreted as glacial, contain: uni- and multidirectionally striated clasts; striated clasts with environmentally diagnostic shapes (wedges and bullets); and occasionally striated fossiliferous (Siluro-Devonian faunal assemblages) and non-fossiliferous erratics. The sequences represent proximal sedimentation associated with a wasting ice-front, south of the Wangaratta area. Associated with these sediments are seven pavement surfaces, recognised as glacial (one - a miniature roche moutonnee) and indicating ice-movement from south to north. Petrographic data show derivation of non-fossiliferous erratics from local and distant source terrains south of the study area. Palaeontological data show derivation of the exotic fossiliferous erratics from beyond the present southern margin of the Australian craton. Local preservation and general distribution of glacial deposits reflects original Permian topography rather than subsequent graben tectonics. There is no geological evidence for an Ovens Graben. The present landscape reflects tilt-block tectonics similar in structural pattern to that developed across the north of the state, and is in part at least a preserved Permian feature. The radiometric age of basalt in Glenrowan Gap (on the western side of the Ovens tilt-block) demonstrates the Gap's existence before 36 Ma. Glacials suggest a relict Permian ice-spill path to the NW

Adaptive maternal investment in the wild? Links between maternal growth trajectory and offspring size, growth, and survival in contrasting environments

Life history theory predicts that investment per offspring should correlate negatively with the quality of environment offspring are anticipated to encounter; parents may use their own experience as juveniles to predict this environment and may modulate offspring traits such as growth capacity as well as initial size. We manipulated nutrient levels in the juvenile habitat of wild Atlantic salmon Salmo salar to investigate the hypothesis that the egg size maximizing juvenile growth and survival depends on environmental quality. We also tested whether offspring traits were related to parental growth trajectory. Mothers that grew fast when young produced more, smaller offspring than mothers that had grown slowly to reach the same size. Despite their size disadvantage, offspring of faster-growing mothers grew faster than those of slow-growing mothers in all environments, counter to the expectation that they would be competitively disadvantaged. However, they had lower relative survival in environments where the density of older predatory/competitor fish was relatively high. These links between maternal (but not paternal) growth trajectory and offspring survival rate were independent of egg size, underscoring that mothers may be adjusting egg traits other than size to suit the anticipated environment faced by their offspring

Scaling-up beginning farmers for wholesale production

With nearly 15 million people that live within 250 miles of Kansas City, the demand for local food is increasing. Local beginning farmers in the region want to reach an emerging wholesale market. However, selling directly to consumers demands different skills than the wholesale market requires. There are many educational programs offered in the region that are focused on direct to consumer sales. Unfortunately, there is a gap in educational programs that are offered to support beginning farmers that wish to expand into wholesale markets. In 2018, the Beginning Farmer Wholesale Project was started within the Growing Growers Kansas City program in congruence with the overall mission to improve the skills and livelihoods of the region’s growers. The project offers support and training to beginning farmers as they begin to navigate new market opportunities. It provides on-farm technical assistance, mentorship, opportunities to connect to wholesale buyers, a workshop series, a manual and an extensive foodshed GIS map. The ongoing project has seen several contributions to improving farmer access to wholesale markets. As of 2020, six workshops have been conducted that have covered a variety of farm production and marketing skills. Six farmer mentees have enrolled in the mentor program which enlists nine farmer mentors from across the region. Over twenty farmers have utilized the technical assistance service on their Kansas and Missouri farm operations and the farmer buyer matching program has resulted in thirteen beginning farmers gaining access to new markets. The project highlights the value of collaboration among organizations and the importance of offering multiple farmer services in order to improve wholesale access

Telomere elongation during early development is independent of environmental temperatures in Atlantic salmon

There is increasing evidence from endothermic vertebrates that telomeres, which cap the ends of chromosomes and play an important role in chromosome protection, decline in length during postnatal life and are a useful indicator of physiological state and expected lifespan. However, much less is currently known about telomere dynamics in ectothermic vertebrates, which are likely to differ from that of endotherms, at least in part due to the sensitivity of ectotherm physiology to environmental temperature. We report here on an experiment in which Atlantic salmon were reared through the embryonic and larval stages of development, and under differing temperatures, in order to examine the effects of environmental temperature during early life on telomere dynamics, oxidative DNA damage and cellular proliferation. Telomere length significantly increased between the embryonic and larval stages of development. Contrary to our expectations, variation in telomere length at the end of the larval stage was unrelated to either cell proliferation rate or the relative level of oxidative DNA damage, and did not vary between the temperature treatments. This study suggests that salmon are able to restore the length of their telomeres during early development, which may possibly help to buffer potentially harmful environmental effects experienced in early life

Statistical mechanics of voting

Decision procedures aggregating the preferences of multiple agents can produce cycles and hence outcomes which have been described heuristically as `chaotic'. We make this description precise by constructing an explicit dynamical system from the agents' preferences and a voting rule. The dynamics form a one dimensional statistical mechanics model; this suggests the use of the topological entropy to quantify the complexity of the system. We formulate natural political/social questions about the expected complexity of a voting rule and degree of cohesion/diversity among agents in terms of random matrix models---ensembles of statistical mechanics models---and compute quantitative answers in some representative cases.Comment: 9 pages, plain TeX, 2 PostScript figures included with epsf.tex (ignore the under/overfull \vbox error messages