12,642 research outputs found
Toward a More realistic Evaluation of the United Nations
ITALIACopia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201
Causes and biophysical consequences of cellulose production by Pseudomonas fluorescens SBW25 at the air-liquid interface
Cellulose over-producing wrinkly spreader mutants of Pseudomonas fluorescens SBW25 have been the focus of much investigation, but conditions promoting the production of cellulose in ancestral SBW25, its effects and consequences have escaped in-depth investigation through lack of in vitro phenotype. Here, using a custom built device, we reveal that in static broth microcosms ancestral SBW25 encounters environmental signals at the air-liquid interface that activate, via three diguanylate cyclase-encoding pathways (Wsp, Aws and Mws), production of cellulose. Secretion of the polymer at the meniscus leads to modification of the environment and growth of numerous micro-colonies that extend from the surface. Accumulation of cellulose and associated microbial growth leads to Rayleigh-Taylor instability resulting in bioconvection and rapid transport of water-soluble products over tens of millimetres. Drawing upon data we build a mathematical model that recapitulates experimental results and captures the interactions between biological, chemical and physical processes.IMPORTANCE This work reveals a hitherto unrecognized behaviour that manifests at the air-liquid interface, which depends on production of cellulose, and hints to undiscovered dimensions to bacterial life at surfaces. Additionally, the study links activation of known diguanylate cyclase-encoding pathways to cellulose expression and to signals encountered at the meniscus. Further significance stems from recognition of the consequences of fluid instabilities arising from surface production of cellulose for transport of water-soluble products over large distances
High speed flight vehicle control Patent
Supersonic or hypersonic vehicle control system comprising elevons with hinge line sweep and free of adverse aerodynamic cross couplin
Reconciling WTP to actual adoption of green energy tariffs: A diffusion model of an induced environmental marke
This paper develops a formal model that links the willingness to pay (WTP) literature with the established innovation diffusion literature. This concern arises from an attempt to reconcile the large disparities that have been observed between actual adoption of green energy tariffs and WTP for such tariffs. These disparities have often been attributed to upward response bias and the free rider problem. However, empirical research indicates that other factors have hindered the development of green energy markets, including supply side problems and poor regulation. Using an epidemic diffusion framework our model shows how increasing consumer environmental concern driven by word of mouth and mass media communication channels results in a growing number of people who state they are WTP for green energy. The presence of upward response bias and the free rider problem result in 'feasible adoption' being below stated WTP. Feasible adoption is, in turn, differentiated from actual adoption by the extent of market imperfections. It is concluded that; (1) the potential of such markets may take time to reap and that the low penetration rates of today may reflect a conventional diffusion trajectory and (2); low and stable energy prices appear to be a precondition if consumers are to contribute substantively to the funding of renewables investments through green tariffs.Willingness-to-pay, innovation diffusion, green energy, environmental valuation
On the prediction of critical flutter conditions from subcritical response data and some related wind-tunnel experience
Methods of interpreting response measurements which could be amenable to flight flutter testing procedures were studied analytically and in the wind tunnel. One suggested scheme, which requires evaluation, is an iterative technique in which derivatives obtained from subcritical response data are used to indicate the approach to flutter. A simplification of this procedure was considered by examining the manner in which a single characteristic of the subcritical response behaves in relation to variations of the density or dynamic pressure in the approach to flutter. The use of this single parameter scheme was examined for random excitation as well as for sinusoidal forcing. The feasibility of the method is illustrated by several examples and the relative merits of random and sinusoidal excitation are discussed
Financial Risk, Innovation and Alternative Pathways to Decarbonising the Energy System in 2050
There is a lot of forward looking work attempting to envisage the decarbonised energy system of the future as reflected with current interest in 'smart grids'. A central tenet behind most visions of the 'smart grids' of the future are the price signals that financial and commodity markets will deliver to facilitate effective and efficient resource allocation. Most of these visions take stylised and static views of financial and commodity markets despite the fact that these markets are experiencing dramatic change due to innovation and regulation. Accordingly, the paper maps the risks associated in the fusion of financial innovation with innovation in the energy system through a theoretical framework that draws on evolutionary models of paradigm shift. Risks to both the financial and energy systems are characterised as either emanating from primary or secondary markets and these are explored in terms of alternative visions of the energy system in the long run
TAX INCENTIVES: AN EFFECTIVE DEVELOPMENT STRATEGY FOR RURAL COMMUNITIES?
As national and local economies become more globalized, many rural areas are going to find it more difficult to compete for private capital investments. A traditional tool, modifications to tax policy, of state and local governments will not be as effective (for many communities it has never been effective) in the future. These communities will need to seek other avenues of growth. However, for many rural communities even alternative avenues will not lead to enhanced economic opportunity.agglomeration, rural development, tax policy, Community/Rural/Urban Development, R51, R58, O21, O23, R11, R38,
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