An experimental investigation of the interior noise control effects of propeller synchrophasing

A simplified cylindrical model of an aircraft fuselage is used to investigate the mechanisms of interior noise suppression using synchrophasing techniques. This investigation allows isolation of important parameters to define the characteristics of synchrophasing. The optimum synchrophase angle for maximum noise reduction is found for several interior microphone positions with pure tone source excitation. Noise reductions of up to 30 dB are shown for some microphone positions, however, overall reductions are less. A computer algorithm is developed to decompose the cylinder vibration into modal components over a wide range of synchrophase angles. The circumferential modal response of the shell vibration is shown to govern the transmission of sound into the cylinder rather than localized transmission. As well as investigating synchrophasing, the interior sound field due to sources typical of propellers has been measured and discussed

The Making of the Botanical Battle Ground: Domestication and the Origins of the Worlds’ Weed Floras

The essays in this volume honour a man whose research over the last four decades has exemplified the potential of archaeology, archaeological science and their cognate disciplines to address central questions about food and human nature. The volume comprises 17 thematic papers, all focused on the archaeology of food and arranged into three sections reflecting Martin Jones’ wide-ranging career. The first section, A Botanical Battleground, honours his central role in the development of archaeobotany and biomolecular archaeology. The second, The Stomach and the Soul, discusses the archaeology of food from evolutionary perspectives; while the final section, Between Fertile Crescents, connects to his recent research on food globalization in prehistory. The assembled chapters emphasize not only the food itself, but also the communities who produced and consumed it, as Martin Jones has repeatedly demonstrated that it is the interconnection between social and biological discourses that sheds most light on the human past. Far from the time when the first hearth was ever built, the research of archaeologists connects the meals of the present to past communities and their interconnections to each other and to plants

Sparrow therapeutics exit strategy

The case focuses on Ken Powers, cofounder and chief executive officer of Sparrow Therapeutics, whose young biotechnology company has reached a critical stage where he has to decide whether or not to sell. The company's three main sets of investors have different priorities: (1) a quick cash sale now, (2) delay sale for about a year if returns are greater, and (3) delay sale for 2 years, build company value, and retain autonomy. What choice would be best for the company, for its investors-and for Ken himself? And when would be the best time to implement the exit strategy

Domestication as innovation : the entanglement of techniques, technology and chance in the domestication of cereal crops

The origins of agriculture involved pathways of domestication in which human behaviours and plant genetic adaptations were entangled. These changes resulted in consequences that were unintended at the start of the process. This paper highlights some of the key innovations in human behaviours, such as soil preparation, harvesting and threshing, and how these were coupled with genetic ‘innovations’ within plant populations. We identify a number of ‘traps’ for early cultivators, including the needs for extra labour expenditure on crop-processing and soil fertility maintenance, but also linked gains in terms of potential crop yields. Compilations of quantitative data across a few different crops for the traits of nonshattering and seed size are discussed in terms of the apparently slow process of domestication, and parallels and differences between different regional pathways are identified. We highlight the need to bridge the gap between a Neolithic archaeobotanical focus on domestication and a focus of later periods on crop-processing activities and labour organization. In addition, archaeobotanical data provide a basis for rethinking previous assumptions about how plant genetic data should be related to the origins of agriculture and we contrast two alternative hypotheses: gradual evolution with low selection pressure versus metastable equilibrium that prolonged the persistence of ‘semi-domesticated’ populations. Our revised understanding of the innovations involved in plant domestication highlight the need for new approaches to collecting, modelling and integrating genetic data and archaeobotanical evidence