Benefits of slush hydrogen for space missions

A study was performed to quantify the benefits of using slush hydrogen instead of normal boiling point liquid hydrogen as a fuel for several space missions. Vehicles considered in the study included the Space Shuttle/Shuttle-C, LEO to GEO transfer vehicles, Lunar and Mars transfer vehicles, and cryogenic depots in low Earth orbit. The advantages of using slush hydrogen were expressed in terms of initial mass differences at a constant payload, payload differences at a constant tank volume, and increases in fuel storage time for cryogenic depots. Both chemical oxygen/hydrogen and hydrogen nuclear thermal rocket propulsion were considered in the study. The results indicated that slush hydrogen offers the potential for significant decreases in initial mass and increases in payload for most missions studied. These advantages increase as the mission difficulty, or energy, increases

Restructuring the Swazi sugar industry: The changing role and political significance of smallholders

© 2016 The Author(s). Since Independence, the contribution of Swazi smallholder farmers to sugar production has grown greatly. This is in part due to a change in the political support that the farmers have received from the Swazi state. Initially viewed with suspicion and as a challenge to royal hegemony, smallholder sugar cane production is now seen as a crucial means of overcoming rural poverty in Swaziland’s poorest region, the semi-arid lowveld. Provision of irrigation water is vital for successful sugar cane production on the co-operatively managed farms that are necessary to achieve the economies of scale in irrigated sugar production. Threats to their profitability arising from increasingly volatile markets facing Swaziland’s sugar industry since changes to the EU Sugar Protocol in 2005 undermine their capacity for co-operative governance and challenge their long-term viability. EU support to facilitate adjustment to the new sugar market has led to increased sugar cane production by smallholders. The paper argues that the two big dam projects that are at the heart of the new irrigation regions are politically ‘too big to fail’, which has committed the Swazi state to the long-term support of smallholders to ensure repayment of loans to build the dams. At the same time, the success of commercial small-scale sugar cane production poses challenges to the Swazi model of customary land tenure. Although emblematic of autocratic royal power, it also - in the processes of land and water development for commercial smallholder sugar cane production - suggests limits to how that power may be deployed in the changing relationships between Swazi elites and their corporate partners and the diverse classes of rural stakeholders

Analytic lymph node number establishes staging accuracy by occult tumor burden in colorectal cancer.

BACKGROUND AND OBJECTIVES: Recurrence in lymph node-negative (pN0) colorectal cancer suggests the presence of undetected occult metastases. Occult tumor burden in nodes estimated by GUCY2C RT-qPCR predicts risk of disease recurrence. This study explored the impact of the number of nodes analyzed by RT-qPCR (analytic) on the prognostic utility of occult tumor burden. METHODS: Lymph nodes (range: 2-159) from 282 prospectively enrolled pN0 colorectal cancer patients, followed for a median of 24 months (range: 2-63), were analyzed by GUCY2C RT-qPCR. Prognostic risk categorization defined using occult tumor burden was the primary outcome measure. Association of prognostic variables and risk category were defined by multivariable polytomous and semi-parametric polytomous logistic regression. RESULTS: Occult tumor burden stratified this pN0 cohort into categories of low (60%; recurrence rate (RR) = 2.3% [95% CI 0.1-4.5%]), intermediate (31%; RR = 33.3% [23.7-44.1%]), and high (9%; RR = 68.0% [46.5-85.1%], P \u3c 0.001) risk of recurrence. Beyond race and T stage, the number of analytic nodes was an independent marker of risk category (P \u3c 0.001). When \u3e12 nodes were analyzed, occult tumor burden almost completely resolved prognostic risk classification of pN0 patients. CONCLUSIONS: The prognostic utility of occult tumor burden assessed by GUCY2C RT-qPCR is dependent on the number of analytic lymph nodes

Headroom approach to device development: Current and future directions

OBJECTIVES: The headroom approach to medical device development relies on the estimation of a value-based price ceiling at different stages of the development cycle. Such price-ceilings delineate the commercial opportunities for new products in many healthcare systems. We apply a simple model to obtain critical business information as the product proceeds along a development pathway, and indicate some future directions for the development of the approach. METHODS: Health economic modelling in the supply-side development cycle for new products. RESULTS: The headroom can be used: initially as a 'reality check' on the viability of the device in the healthcare market; to support product development decisions using a real options approach; and to contribute to a pricing policy which respects uncertainties in the reimbursement outlook. CONCLUSIONS: The headroom provides a unifying thread for business decisions along the development cycle for a new product. Over the course of the cycle attitudes to uncertainty will evolve, based on the timing and manner in which new information accrues. Within this framework the developmental value of new information can justify the costs of clinical trials and other evidence-gathering activities. Headroom can function as a simple shared tool to parties in commercial negotiations around individual products or groups of products. The development of similar approaches in other contexts holds promise for more rational planning of service provision

Organic-Conventional Dairy Systems Trial in New Zealand: Four Years’ Results

The Organic-Conventional Comparative Dairy Systems trial at Massey University began in August 2001, and the organic farmlet achieved certification in August 2003. The trial is unique because it is the only comparative grassland-based open grazing dairy study in the world. The organic and conventional systems are managed individually according to best practice, and both are intensively monitored for production, animal health, and environmental impacts. The systems remained similar for the first two years, but began to diverge in the third and fourth years. Production has been 10-20% lower on the organic farm, but environmental impacts appear to be less than on the conventional unit, and net incomes would be similar given a 20% price premium for the organic product. Animal health issues have been manageable on the organic farmlet, and not too dissimilar from the conventional farmlet. Full results after four years of the trial will be available and presented at the conference