Establishing confidence in CCV/ACT technology

Despite significant advancements in controls configured vehicles/active controls technology (CCV/ACT) in the past decade, few applications of this promising technology have appeared in recent aircraft designs. The status of CCV/ACT is summarized, and some of the constraints which are retarding its wider application are described. Suggestions toward establishing an increased level of confidence in the technology are given

Comparative analyses of space-to-space central power stations

The technological and economical impact of a large central power station in Earth orbit on the performance and cost of future spacecraft and their orbital transfer systems are examined. It is shown that beaming power to remote users cannot be cost effective if the central power station uses the same power generation system that is readily available for provision of onboard power and microwave transmission and reception of power through space for use in space is not cost competitive with onboard power or propulsion systems. Laser and receivers are required to make central power stations feasible. Remote power transmission for propulsion of orbital transfer vehicles promises major cost benefits. Direct nuclear pumped or solar pumped laser power station concepts are attractive with laser thermal and laser electric propulsion systems. These power stations are also competitive, on a mass and cost basis, with a photovoltaic power station

The orbital recovery problem. Part II - Application of analysis technique to selection of recovery sites for return from low circular orbits

Lateral range requirements used in selecting spacecraft landing recovery sites for return from low circular orbit

Review: Management of midshaft clavicle fractures in adolescents

Clavicle fractures are common injuries that occur across all age ranges, but are largely seen in young, active males. The majority of these fractures (70-80%) occur in the midshaft of the clavicle. The purpose of this review was to compare non-operative treatment to operative treatment of midclavicular fractures and determine whether treatment for adolescent clavicle fractures more closely aligns with pediatric or adult management. Adolescent clavicle fractures are increasingly treated with open reduction and internal fixation, especially in the 15 to 19 age group. Nevertheless, there remains a lack of high-level studies comparing outcomes of operative and conservative treatment specifically for the adolescent population to justify this recent trend. These findings expose the need for a prospective study to provide a framework for treatment, and they suggest that physicians have become overaggressive in their management of mid-shaft clavicle fractures in adolescents

Organic Farming Policies and the Growth of the Organic Sector in Denmark and the UK: A Comparative Analysis

There has been little systematic analysis of the extent to which organic farming policies have influenced growth in the organic sector. Analyses of organic farming policy instruments, for the most part, provide extensive and detailed reviews of instruments applied either in a single country or across countries. Hence, there is a great need to examine systematically whether there is a relationship between the introduction of organic farming policies and the growth of the organic food sector, and whether particular designs of organic farming policies are more effective than others. In this paper, we take the first step in the endeavour of analysing the effects of organic farming by undertaking an econometric analysis of the relationship between organic farming policies in Denmark and the UK and their effects on the number of farmers and growers converting to organic production.organic farming, policy, Agricultural and Food Policy, Farm Management,

BAYES' ESTIMATES OF THE DOUBLE HURDLE MODEL IN THE PRESENCE OF FIXED COSTS

We present a model of market adoption (participation) where the presence of non-negligible fixed costs leads to non-zero censoring of the traditional double-hurdle regression. Fixed costs arise due to household resources that must be devoted a priori to the decision to participate in the market. These costs-usually a cost of time-motivate two-step decision-making and focus attentions on the minimum-efficient scale of operations (the minimum amount of milk sales) at which market entry becomes viable. This focus, in turn, motivates a non-zero-censored Tobit regression estimated through routine application of Markov chain Monte Carlo Methods.market participation, fixed costs, double-hurdle model, censored regression., Financial Economics, O1, O11, C34, O13, Q16, D1,