1,157 research outputs found
ECONOMIC AND SOCIAL CONSEQUENCES OF BIOTECHNOLOGY: A SCENARIO ANALYSIS
Over the years agricultural technology has created remarkable commodity production growth rates and enhanced general economic growth through food production, manufactured goods and trade for most nations. Biotechnology holds the promise of continuing this remarkable record. There is a long list of potential benefits of biotechnology but unfortunately the perceived costs/risks are also many. These concerns have lead to significant consumer reluctance to accept the technology and, in some cases, outright consumer rejection of the technology. To discuss the future of biotechnology, scenario analysis is used to examine the social and economic impact of biotechnology on industrialized and emerging nations. Four scenarios are discussed in detail: biotechnology may be formally or informally banned (Scenario 1), fully accepted (Scenario 2), marketed through strict labeling (Scenario 3), or limited to non-food applications (Scenario 4). Consumer acceptance of this technology will be key to determining which scenario becomes the future for each nation. The likelihood of each scenario is different for each nation, the U.S. will most likely evolve into scenario 2 or 3, while in the EU scenarios 1 or 4 are more likely. Determining the future for emerging nations is extremely complex and dependent on several factors like malnutrition rates, environmental safety and historical trading routes. Each scenario has a major impact on small producers worldwide which ultimately influences the health of rural communities. The analysis indicates that emerging nations are the most sensitive to the timing of decisions being made about the future of biotechnology. If biotechnology becomes a reality, new data will be required to assess the social and economic impact of this technology.Research and Development/Tech Change/Emerging Technologies,
On Pebble Automata for Data Languages with Decidable Emptiness Problem
In this paper we study a subclass of pebble automata (PA) for data languages
for which the emptiness problem is decidable. Namely, we introduce the
so-called top view weak PA. Roughly speaking, top view weak PA are weak PA
where the equality test is performed only between the data values seen by the
two most recently placed pebbles. The emptiness problem for this model is
decidable. We also show that it is robust: alternating, nondeterministic and
deterministic top view weak PA have the same recognition power. Moreover, this
model is strong enough to accept all data languages expressible in Linear
Temporal Logic with the future-time operators, augmented with one register
freeze quantifier.Comment: An extended abstract of this work has been published in the
proceedings of the 34th International Symposium on Mathematical Foundations
of Computer Science (MFCS) 2009}, Springer, Lecture Notes in Computer Science
5734, pages 712-72
Streaming Tree Transducers
Theory of tree transducers provides a foundation for understanding
expressiveness and complexity of analysis problems for specification languages
for transforming hierarchically structured data such as XML documents. We
introduce streaming tree transducers as an analyzable, executable, and
expressive model for transforming unranked ordered trees in a single pass.
Given a linear encoding of the input tree, the transducer makes a single
left-to-right pass through the input, and computes the output in linear time
using a finite-state control, a visibly pushdown stack, and a finite number of
variables that store output chunks that can be combined using the operations of
string-concatenation and tree-insertion. We prove that the expressiveness of
the model coincides with transductions definable using monadic second-order
logic (MSO). Existing models of tree transducers either cannot implement all
MSO-definable transformations, or require regular look ahead that prohibits
single-pass implementation. We show a variety of analysis problems such as
type-checking and checking functional equivalence are solvable for our model.Comment: 40 page
Scale-Up and On-Line Monitoring of Gas-Solid Systems using Advanced and Non-Invasive Measurement Techniques
Industry relies on gas-solid systems for numerous processes. Flow dynamics play an important role in achieving the desired results. The present study proposes, validates and demonstrates a novel mechanistic scale-up approach based on maintaining similar radial profile or cross sectional distribution of gas holdup in two different gas-solid systems in order to achieve hydrodynamics similarity using advanced measurement techniques. This new methodology for scale-up and design has been implemented on gas-solid spouted bed which has been used for drying, granulation and coating. The development can be extrapolated to other gas-solid systems encountered in phosphate processes
Ghost Condensate Busting
Applying the Thomas-Fermi approximation to renormalizable field theories, we
construct ghost condensation models that are free of the instabilities
associated with violations of the null-energy condition.Comment: 9 pages, minor corrections, a reference added, the discussion on
consistency of the Thomas-Fermi approximation expanded, to appear in JCA
Relativistic Acoustic Geometry
Sound wave propagation in a relativistic perfect fluid with a non-homogeneous
isentropic flow is studied in terms of acoustic geometry. The sound wave
equation turns out to be equivalent to the equation of motion for a massless
scalar field propagating in a curved space-time geometry. The geometry is
described by the acoustic metric tensor that depends locally on the equation of
state and the four-velocity of the fluid. For a relativistic supersonic flow in
curved space-time the ergosphere and acoustic horizon may be defined in a way
analogous the non-relativistic case. A general-relativistic expression for the
acoustic analog of surface gravity has been found.Comment: 14 pages, LaTe
An automaton over data words that captures EMSO logic
We develop a general framework for the specification and implementation of
systems whose executions are words, or partial orders, over an infinite
alphabet. As a model of an implementation, we introduce class register
automata, a one-way automata model over words with multiple data values. Our
model combines register automata and class memory automata. It has natural
interpretations. In particular, it captures communicating automata with an
unbounded number of processes, whose semantics can be described as a set of
(dynamic) message sequence charts. On the specification side, we provide a
local existential monadic second-order logic that does not impose any
restriction on the number of variables. We study the realizability problem and
show that every formula from that logic can be effectively, and in elementary
time, translated into an equivalent class register automaton
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