5,176 research outputs found
THE ECONOMIC IMPACT OF GENETICALLY MODIFIED ORGANISMS IN SMALL DEVELOPING COUNTRIES
The expected benefits from herbicide resistant transgenic rice in Uruguay are estimated with stochastic simulation techniques. Economic surplus methods that account for private profits are used to measure the magnitude and distribution of the benefits between producers and a multinational firm. Further, the adoption rate of transgenic rice is endogenous in the model and depends on the expected profitability of the technology. The results show that the potential benefits from the technology are relatively small because of the small production base. Multinational firms are, therefore, unlikely to develop locally adapted transgenic rice varieties without strategic partnerships with local institutions.Research and Development/Tech Change/Emerging Technologies,
Proposal for a Precision Measurement of |Vub|
A new method for a precision measurement of the CKM matrix element |Vub| is
discussed, which combines good theoretical control with high efficiency and a
powerful discrimination against charm background. The resulting combined
theoretical uncertainty on |Vub| is estimated to be 10%.Comment: 4 pages, 2 figures, RevTe
A TE11 Dual-Mode Monoblock Dielectric Resonator Filter
A novel TE11 monoblock dual-mode dielectric resonator filter is presented in this paper. The proposed filter is made of a single piece of ceramic with silver plated external surfaces and metallic lids for hosting tuning elements. The dominant TE11 dual-mode is supported by H-shape dielectric resonator having r =45. The resonator is ultra-compact in size and offers a maximized space utilization since no metallic housing is required. In addition, the proposed resonator offers a high unloaded quality factor, reasonably wide spurious window and lend itself to implement tunability. One prototype filter operating at 1.96 GHz with 50-MHz bandwidth is designed
Scaling Laws for Advection Dominated Flows: Applications to Low Luminosity Galactic Nuclei
We present analytical scaling laws for self-similar advection dominated
flows. The spectra from these systems range from 10 - 10 Hz, and
are determined by considering cooling of electrons through synchrotron,
bremsstrahlung, and Compton processes. We show that the spectra can be quite
accurately reproduced without detailed numerical calculations, and that there
is a strong testable correlation between the radio and X-ray fluxes from these
systems. We describe how different regions of the spectrum scale with the mass
of the accreting black hole, , the accretion rate of the gas, , and
the equilibrium temperature of the electrons, . We show that the universal
radio spectral index of 1/3 observed in most elliptical galaxies (Slee et al.
1994) is a natural consequence of self-absorbed synchrotron radiation from
these flows. We also give expressions for the total luminosity of these flows,
and the critical accretion rate, , above which the advection
solutions cease to exist. We find that for most cases of interest the
equilibrium electron temperature is fairly insensitive to , , and
parameters in the model. We apply these results to low luminosity black holes
in galactic nuclei. We show that the problem posed by Fabian & Canizares (1988)
of whether bright elliptical galaxies host dead quasars is resolved, as pointed
out recently by Fabian & Rees (1995), by considering advection-dominated flows.Comment: 30 pages, 5 postscript files. Accepted to ApJ. Also available
http://cfa-www.harvard.edu/~rohan/publications.htm
Changes in Penile Hemodynamics after Intracavernous Injection of Prostaglandin E1 and Prostaglandin I2 in Pigtailed Monkeys
Local and Systemic Effects of Chronic Intracavernous Injection of Papaverine, Prostaglandine E1 and Saline in Primates
Cannibalism as a life boat mechanism
Under certain conditions a cannibalistic population can survive when food for the adults is too scarce to support a non-cannibalistic population. Cannibalism can have this lifeboat effect if (i) the juveniles feed on a resource inaccessible to the adults; and (ii) the adults are cannibalistic and thus incorporate indirectly the inaccessible resource. Using a simple model we conclude that the mechanism works when, at low population densities, the average yield, in terms of new offspring, due to the energy provided by one cannibalized juvenile is larger than one
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