Duck fleas as evidence for eiderdown production on archaeological sites

Acknowledgements This project was undertaken as part of my doctoral studies funded by the Commonwealth Scholarship Commission (CACR-2009-39) in the United Kingdom. I would like to thank my supervisors Karen Milek and Andrew Dugmore for their help and support. I also wish to thank Jónas Helgason, his son Alexius Jónasson and Baldur Vilhelmsson for kindly having allowed access to the eiderdown stores and workshops at Æðey and Vatnsfjörður and for having provided assistance when needed. I would like to thank Fornleifastofnun Íslands for supporting my fieldwork at Vatnsfjörður, as well as Paul Ledger and Garðar Guðmundsson for their help during fieldwork. I am especially grateful to Richard Marriott for his invaluable help with flea identifications and for lending me reference material. Erling Ólafsson and Jan Klimaszewski also helped with the beetle identifications. Consultation of the BugsCEP database (Buckland and Buckland, 2006) aided the redaction of this paper.

Resilience of small-scale societies’ livelihoods: a framework for studying the transition from food gathering to food production

The origins of agriculture and the shift from hunting and gathering to committed agriculture is regarded as one of the major transitions in human history. Archeologists and anthropologists have invested significant efforts in explaining the origins of agriculture. A period of gathering intensification and experimentation and pursuing a mixed economic strategy seems the most plausible explanation for the transition to agriculture and provides an approach to study a process in which several nonlinear processes may have played a role. However, the mechanisms underlying the transition to full agriculture are not completely clear. This is partly due to the nature of the archeological record, which registers a practice only once it has become clearly established. Thus, points of transitions have limited visibility and the mechanisms involved in the process are difficult to untangle. The complexity of such transitions also implies that shifts can be distinctively different in particular environments and under varying historical and social conditions. In this paper we discuss some of the elements involved in the transition to food production within the framework of resilience theory. We propose a theoretical conceptual model in which the resilience of livelihood strategies lies at the intersection of three spheres: the environmental, economical, and social domains. Transitions occur when the rate of change, in one or more of these domains, is so elevated or its magnitude so large that the livelihood system is unable to bounce back to its original state. In this situation, the system moves to an alternative stable state, from one livelihood strategy to another.

Ethanol production from brown seaweed using non-conventional yeasts

The use of macroalgae (seaweed) as a potential source of biofuels has attracted considerable worldwide interest. Since brown algae, especially the giant kelp, grow very rapidly and contain considerable amounts of polysaccharides, coupled with low lignin content, they represent attractive candidates for bioconversion to ethanol through yeast fermentation processes. In the current study, powdered dried seaweeds (Ascophylum nodosum and Laminaria digitata) were pre-treated with dilute sulphuric acid and hydrolysed with commercially available enzymes to liberate fermentable sugars. Higher sugar concentrations were obtained from L. digitata compared with A. nodosum with glucose and rhamnose being the predominant sugars, respectively, liberated from these seaweeds. Fermentation of the resultant seaweed sugars was performed using two non-conventional yeast strains: Scheffersomyces (Pichia) stipitis and Kluyveromyces marxianus based on their abilities to utilise a wide range of sugars. Although the yields of ethanol were quite low (at around 6 g/L), macroalgal ethanol production was slightly higher using K. marxianus compared with S. stipitis. The results obtained demonstrate the feasibility of obtaining ethanol from brown algae using relatively straightforward bioprocess technology, together with non-conventional yeasts. Conversion efficiency of these non-conventional yeasts could be maximised by operating the fermentation process based on the physiological requirements of the yeasts.

Co-digestion of terrestrial plant biomass with marine macro-algae for biogas production

This paper investigates factors affecting anaerobic degradation of marine macro-algae (or seaweed), when used as a co-substrate with terrestrial plant biomass for the production of biogas. Using Laminaria digitata, a brown marine seaweed species and green peas, results showed that when only 2% of feedstock of a reactor treating the green peas at an organic loading rate (OLR) of 2.67 kg VS.m3.day-1 was replaced with the seaweed, methane production was disrupted, whilst acidogenesis, seemed to be less adversely affected, resulting in excessive volatile acids accumulation. Reactor stability was difficult to achieve thereafter. The experiment was repeated with a lower initial OLR of green peas of 0.70 kg VS.m3.day-1 before the addition of the seaweed. Although similar symptoms as in first trial were observed, process stability was restored through the control of OLR and alkalinity. These measures led to an increase in overall OLR of 1.25 kg VS.m3.day-1 comprising of 35% seaweed. This study has shown that certain seaweed constituents are more inhibitory to the methanogens even at trace concentrations than to the other anaerobic digestion microbial groups. Appropriate adaptation strategy, involving initial low proportion of the seaweed relative to the total OLR, and overall low OLR, is necessary to ensure effective adaptation of the microorganisms to the inhibitory constituents of seaweed. Where there is seasonal availability of seaweed, the results of this study suggest that a fresh adaptation or start-up strategy must be implemented during each cycle of seaweed availability in order to ensure sustainable process stability.

Infants, interfaces, and intermediation: digital parenting and the production of 'iPad baby' videos on YouTube

We investigate the ways young children’s use of mobile touchscreen interfaces is both understood and shaped by parents through the production of YouTube videos and discussions in associated comment threads. This analysis expands on, and departs from, theories of parental mediation, which have traditionally been framed through a media effects approach in analyzing how parents regulate their children’s use of broadcast media, such as television, within family life. We move beyond the limitations of an effects framing through more culturally and materially oriented theoretical lenses of mediation, considering the role mobile interfaces now play in the lives of infants through analysis of the ways parents intermediate between domestic spaces and networked publics. We propose the concept of intermediation, which builds on insights from critical interface studies as well as cultural industries literature to help account for these expanded aspects of digital parenting. Here, parents are not simply moderating children’s media use within the home, but instead operating as an intermediary in contributing to online representations and discourses of children’s digital culture. This intermediary role of parents engages with ideological tensions in locating notions of “naturalness:” the iPad’s gestural interface or the child’s digital dexterity.

Saccharomyces cerevisiae in the production of fermented beverages

Abstract: Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively) strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre‐hydrolysis) in the case of beers and whiskies, sucrose‐rich plants (molasses or sugar juice from sugarcane) in the case of rums, or from fruits (which do not require pre‐hydrolysis) in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites) as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations.

Saccharomyces cerevisiae in the production of whisk(e)y

Whisky is a major global distilled spirit beverage. Whiskies are produced from cereal starches that are saccharified, fermented and distilled prior to spirit maturation. The strain of Saccharomyces cerevisiae employed in whisky fermentations is crucially important not only in terms of ethanol yields, but also for production of minor yeast metabolites which collectively contribute to development of spirit flavour and aroma characteristics. Distillers must therefore pay very careful attention to the strain of yeast exploited to ensure consistency of fermentation performance and spirit congener profiles. In the Scotch whisky industry, initiatives to address sustainability issues facing the industry (for example, reduced energy and water usage) have resulted in a growing awareness regarding criteria for selecting new distilling yeasts with improved efficiency. For example, there is now a desire for Scotch whisky distilling yeasts to perform under more challenging conditions such as high gravity wort fermentations. This article highlights the important roles of S. cerevisiae strains in whisky production and describes key fermentation performance attributes sought in distiller's yeast, such as high alcohol yields, stress tolerance and desirable congener profiles. We hope that the information herein will be useful for whisky producers and yeast suppliers in selecting new distilling strains of S. cerevisiae, and for the scientific community to stimulate further research in this area.