Composite reinforced propellant tanks

Design studies involving weight and cost were carried out for several structural concepts applicable to space shuttle disposable tankage. An effective design, a honeycomb stabilized pressure vessel, was chosen. A test model was designed and fabricated

NONLINEAR MODELS FOR MULTI-FACTOR PLANT NUTRITION EXPERIMENTS

Plant scientists are interested in measuring plant response to quantitative treatment factors, e.g. amount of nutrient applied. Response surface methods are often used for experiments with multiple quantitative factors. However, in many plant nutrition studies, second-order response surface models result in unacceptable lack of fit. This paper explores multi-factor nonlinear models as an alternative. We have developed multi-factor extensions of Mitscherlich and Gompertz models, and fit them to data from experiments conducted at the University of Nebraska-Lincoln Horticulture department. These data are typical of experiments for which conventional response surface models perform poorly. We propose design selection strategies to facilitate economical multi-factor experiments when second-order response surface models are unlikely to fit

Future economics of liver transplantation: A 20-year cost modeling forecast and the prospect of bioengineering autologous liver grafts

During the past 20 years liver transplantation has become the definitive treatment for most severe types of liver failure and hepatocellular carcinoma, in both children and adults. In the U.S., roughly 16,000 individuals are on the liver transplant waiting list. Only 38% of them will receive a transplant due to the organ shortage. This paper explores another option: bioengineering an autologous liver graft. We developed a 20-year model projecting future demand for liver transplants, along with costs based on current technology. We compared these cost projections against projected costs to bioengineer autologous liver grafts. The model was divided into: 1) the epidemiology model forecasting the number of wait-listed patients, operated patients and postoperative patients; and 2) the treatment model forecasting costs (pre-transplant-related costs; transplant (admission)-related costs; and 10-year post-transplant- related costs) during the simulation period. The patient population was categorized using the Model for End-Stage Liver Disease score. The number of patients on the waiting list was projected to increase 23% over 20 years while the weighted average treatment costs in the pre-liver transplantation phase were forecast to increase 83% in Year 20. Projected demand for livers will increase 10% in 10 years and 23% in 20 years. Total costs of liver transplantation are forecast to increase 33% in 10 years and 81% in 20 years. By comparison, the projected cost to bioengineer autologous liver grafts is $9.7M based on current catalog prices for iPS-derived liver cells. The model projects a persistent increase in need and cost of donor livers over the next 20 years that's constrained by a limited supply of donor livers. The number of patients who die while on the waiting list will reflect this evergrowing disparity. Currently, bioengineering autologous liver grafts is cost prohibitive. However, costs will decline rapidly with the introduction of new manufacturing strategies and economies of scale

Discounting of money and sex: Effects of commodity and temporal position in stimulant-dependent men and women

Research on delay discounting has contributed to the understanding of numerous addiction-related phenomena. For example, studies have shown that substance dependent individuals discount their addictive substances (e.g., cocaine) more rapidly than they do other commodities (e.g., money). Recent research has shown that substance dependent individuals discount delayed sex more rapidly than delayed money, and their discounting rates for delayed sex were higher than those of non-addicted individuals. The particular reason that delay discounting rates for sex are higher than those for money, however, are unclear. Do individuals discount delayed sex rapidly because immediate sex is particularly appealing or because delayed sex does not retain its value? Moreover, do the same factors influence men and women’s choices? The current study examined delay discounting in four conditions (money now versus money later; sex now versus sex later; money now, versus sex later; sex now versus money later) in cocaine dependent men and women. The procedures used isolated the role of the immediate versus delayed commodity. For men, the higher rates of delay discounting for sex were because delayed sex did not retain its value, whereas both the immediate and delayed commodity influenced the female participants’ decisions

Intentional research design in implementation science: implications for the use of nomothetic and idiographic assessment

The advancement of implementation science is dependent on identifying assessment strategies that can address implementation and clinical outcome variables in ways that are valid, relevant to stakeholders, and scalable. This paper presents a measurement agenda for implementation science that integrates the previously disparate assessment traditions of idiographic and nomothetic approaches. Although idiographic and nomothetic approaches are both used in implementation science, a review of the literature on this topic suggests that their selection can be indiscriminate, driven by convenience, and not explicitly tied to research study design. As a result, they are not typically combined deliberately or effectively. Thoughtful integration may simultaneously enhance both the rigor and relevance of assessments across multiple levels within health service systems. Background on nomothetic and idiographic assessment is provided as well as their potential to support research in implementation science. Drawing from an existing framework, seven structures (of various sequencing and weighting options) and five functions (Convergence, Complementarity, Expansion, Development, Sampling) for integrating conceptually distinct research methods are articulated as they apply to the deliberate, design-driven integration of nomothetic and idiographic assessment approaches. Specific examples and practical guidance are provided to inform research consistent with this framework. Selection and integration of idiographic and nomothetic assessments for implementation science research designs can be improved. The current paper argues for the deliberate application of a clear framework to improve the rigor and relevance of contemporary assessment strategies

"The trauma of competition": the entry of Air Products Inc. into the industrial gases business in Britain and continental Europe 1947-1970

The British Oxygen Company (BOC) had a virtual monopoly on the supply of industrial gases (e.g. oxygen and acetylene) on the British market through the 1950s, when it was finally challenged by an American-based company, Air Products. Air Products Limited (APL) was able to undercut BOCs position, overcoming high barriers to entry to gain significant market share in this sector, which shares some features of network industries. Factors in this success included conditions imposed by the Board of Trade, APL’s innovations, BOC’s slow response, and favourable market conditions. APL’s success had implications for the internationalisation of the industrial gases industry

Culture, entrepreneurship and uneven development: a spatial analysis

Interest in the proposed connection between culture and entrepreneurship has grown significantly in recent years. However, less attention has been given to the nature of the overall impact of this proposed association on development outcomes, particularly at a local level. In response, this paper analyses the relationship between the nature of the culture, entrepreneurship and development experienced across localities, proposing that the link between culture and development is mediated by entrepreneurship. It focuses upon the concept of community culture, as well as embracing a notion of development incorporating both economic and social well-being outcomes. Drawing upon a multivariate spatial analysis of data from localities in Great Britain, the findings indicate that differences in rates of entrepreneurship are strongly influenced by the community culture present in these localities. Furthermore, a bidirectional relationship is found to exist between entrepreneurship and economic and social development outcomes. It is concluded that the embeddedness of local community culture presents a significant challenge for those places seeking to promote entrepreneurially-driven development

Questioning cultural narratives of economic development—an investigation of Kitchener-Waterloo

The version of record [Spigel, B. & Bathelt, H. (2019). Questioning cultural narratives of economic development - An investigation of Kitchener-Waterloo. Canadian Geographer, 63(2), 267-283.] is available online at: https://onlinelibrary.wiley.com/doi/abs/10.1111/cag.12512This paper investigates the relationship between culture and economy and scrutinizes cultural narratives of economic development in Kitchener-Waterloo, southern Ontario. It argues for the need to carefully conceptualize the link between culture and economic development to avoid boosting deterministic stereotypes. In the case of Kitchener-Waterloo, a notable hub of high-technology firms and technology development, a link is frequently drawn between the German community and culture and the region’s technology economy and entrepreneurial culture. A social capital analysis, however, reveals that the German ethnic community neither has the strong professional internal ties nor the external social ties to other regional communities that could constitute a lead role in economic development. Rather, the legacy of Kitchener-Waterloo’s ethnic German population has been absorbed into the region’s self-image and creates a feeling of belonging and common reference points for joint social and economic initiatives in the region