515 research outputs found
Benefit Transfer as Preference Calibration
This paper proposes and illustrates the use of a new approach to benefit transfer for the non-market valuation of environmental resources. It treats transfer as an identification problem that requires assessing whether available benefit estimates permit the parameters of a preference function to be identified. The transfer method proposed uses these identifying restrictions to calibrate preference parameters and bases the benefit estimates on that preference function. The approach is illustrated using travel cost, hedonic and contingent valuation estimates, as well as combinations of estimates. It has three potential advantages over conventional practice: (1) it allows multiple, potentially overlapping estimates of the benefits of an improvement in environmental quality to be combined consistently; (2) it assures the transferred estimates of the benefits attributed to a proposed change can never exceed income; and (3) it provides a set of additional "outputs" that offer plausibility checks of the benefit transfers.
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Experimental evidence on promotion of electric and improved biomass cookstoves.
Improved cookstoves (ICS) can deliver "triple wins" by improving household health, local environments, and global climate. Yet their potential is in doubt because of low and slow diffusion, likely because of constraints imposed by differences in culture, geography, institutions, and missing markets. We offer insights about this challenge based on a multiyear, multiphase study with nearly 1,000 households in the Indian Himalayas. In phase I, we combined desk reviews, simulations, and focus groups to diagnose barriers to ICS adoption. In phase II, we implemented a set of pilots to simulate a mature market and designed an intervention that upgraded the supply chain (combining marketing and home delivery), provided rebates and financing to lower income and liquidity constraints, and allowed households a choice among ICS. In phase III, we used findings from these pilots to implement a field experiment to rigorously test whether this combination of upgraded supply and demand promotion stimulates adoption. The experiment showed that, compared with zero purchase in control villages, over half of intervention households bought an ICS, although demand was highly price-sensitive. Demand was at least twice as high for electric stoves relative to biomass ICS. Even among households that received a negligible price discount, the upgraded supply chain alone induced a 28 percentage-point increase in ICS ownership. Although the bundled intervention is resource-intensive, the full costs are lower than the social benefits of ICS promotion. Our findings suggest that market analysis, robust supply chains, and price discounts are critical for ICS diffusion
Trajectory versus probability density entropy
We study the problem of entropy increase of the Bernoulli-shift map without
recourse to the concept of trajectory and we discuss whether, and under which
conditions if it does, the distribution density entropy coincides with the
Kolmogorov-Sinai entropy, namely, with the trajectory entropy.Comment: 24 page
Stabilizing an Attractive Bose-Einstein Condensate by Driving a Surface Collective Mode
Bose-Einstein condensates of Li have been limited in number due to
attractive interatomic interactions. Beyond this number, the condensate
undergoes collective collapse. We study theoretically the effect of driving
low-lying collective modes of the condensate by a weak asymmetric sinusoidally
time-dependent field. We find that driving the radial breathing mode further
destabilizes the condensate, while excitation of the quadrupolar surface mode
causes the condensate to become more stable by imparting quasi-angular momentum
to it. We show that a significantly larger number of atoms may occupy the
condensate, which can then be sustained almost indefinitely. All effects are
predicted to be clearly visible in experiments and efforts are under way for
their experimental realization.Comment: 4 ReVTeX pages + 2 postscript figure
Exponential Divergence and Long Time Relaxation in Chaotic Quantum Dynamics
Phase space representations of the dynamics of the quantal and classical cat
map are used to explore quantum--classical correspondence in a K-system: as
, the classical chaotic behavior is shown to emerge smoothly and
exactly. The quantum dynamics near the classical limit displays both
exponential separation of adjacent distributions and long time relaxation, two
characteristic features of classical chaotic motion.Comment: 10 pages, ReVTeX, to appear in Phys. Rev. Lett. 13 figures NOT
included. Available either as LARGE (uuencoded gzipped) postscript files or
hard-copies from [email protected]
Entropy production and wave packet dynamics in the Fock space of closed chaotic many-body systems
Highly excited many-particle states in quantum systems such as nuclei, atoms,
quantum dots, spin systems, quantum computers etc., can be considered as
``chaotic'' superpositions of mean-field basis states (Slater determinants,
products of spin or qubit states). This is due to a very high level density of
many-body states that are easily mixed by a residual interaction between
particles (quasi-particles). For such systems, we have derived simple
analytical expressions for the time dependence of energy width of wave packets,
as well as for the entropy, number of principal basis components and inverse
participation ratio, and tested them in numerical experiments. It is shown that
the energy width increases linearly and very quickly saturates.
The entropy of a system increases quadratically, at small
times, and after, can grow linearly, , before the saturation.
Correspondingly, the number of principal components determined by the entropy,
, or by the inverse participation ratio, increases
exponentially fast before the saturation. These results are explained in terms
of a cascade model which describes the flow of excitation in the Fock space of
basis components. Finally, a striking phenomenon of damped oscillations in the
Fock space at the transition to an equilibrium is discussed.Comment: RevTex, 14 pages including 12 eps-figure
Soil Enzymes: Indicator for Soil Health under Fruit based Agri-Horti System
Agroforestry as a sustainable land management system, which increases the yield of the land, combines production of crops (including tree crops) and forest plants and/or animals simultaneously or sequentially. Among the different agroforestry system practices in hill area agri-horti system is one of the most important system because of its specific environmental conditions and natural availability of wide range of fruit trees (citrus, apple, walnut, plum, peach, pear, apricot etc.). In Northwestern hill region viz. Uttarakhand, Himachal Pradesh and Jammu and Kashmir horticulture is the backbone of these states economy which supports about 1.5-2.0 million families and, provides direct or indirect employment to 8-10 million peoples with revenue of more than 1 billion $ (USD) annually. In several studies it was reported that plant’s active root system releases about 17% of photosynthate detained in the form of organic compounds into the rhizosphere, most of which is available to the plant by the different soil microbial activities. The soil enzymatic activity play a significant role in efficient utilization of natural resources through agri-horti production system to enhance the soil sustainability and system productivity by the mechanisms of organic matter decomposition, soil stabilization, nutrient cycling, catalyzing several biochemical reactions in the soil system1,2. In recent years, studies soil enzymes activity have engaged the attention of many researchers. However, most of these studies are confined to agricultural cropping systems3 and forest ecosystems but, information regarding those under temperate fruit crops like peach, pear, apricot, lemon, plum etc., are very limited. The hypothesis of this experiment was that the different temperate fruit crops could have differential microbial activity in the rhizospheric soil (surface and sub-surface), influenced by management practice as well as quality of litter fall and root exudates. We assume that information produced from this study will help in understanding of microbial mediated nutrient dynamics and their management under temperate fruit crops in N-W hilly area
Semiquantal dynamics of fluctuations: Ostensible quantum chaos
The time-dependent variational principle using generalized Gaussian trial
functions yields a finite dimensional approximation to the full quantum
dynamics and is used in many disciplines. It is shown how these 'semi-quantum'
dynamics may be derived via the Ehrenfest theorem and recast as an extended
classical gradient system with the fluctuation variables coupled to the average
variables. An extended potential is constructed for a one-dimensional system.
The semiquantal behavior is shown to be chaotic even though the system has
regular classical behavior and the quantum behavior had been assumed regular.Comment: 9 pages, TeX, 2 figures (not attached; hard copies available
immediately on request). To appear in Physical Review Letter
Towards the Thermodynamics of Localization Processes
We study the entropy time evolution of a quantum mechanical model, which is
frequently used as a prototype for Anderson's localization. Recently Latora and
Baranger [V. Latora, M. Baranger, Phys. Rev.Lett. 82, 520(1999)] found that
there exist three entropy regimes, a transient regime of passage from dynamics
to thermodynamics, a linear in time regime of entropy increase, namely a
thermodynamic regime of Kolmogorov kind, and a saturation regime. We use the
non-extensive entropic indicator recently advocated by Tsallis [ C. Tsallis, J.
Stat. Phys. 52, 479 (1988)] with a mobile entropic index q, and we find that
with the adoption of the ``magic'' value q = Q = 1/2 the Kolmogorov regime
becomes more extended and more distinct than with the traditional entropic
index q = 1. We adopt a two-site model to explain these properties by means of
an analytical treatment and we argue that Q =1/2 might be a typical signature
of the occurrence of Anderson's localization.Comment: 13 pages, 8 figures submitted to Phys. Rev.
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