1,236 research outputs found
A Subjective Equilibrium Approach to the Value of Children in the Agricultural Household
A Philippine sample of agricultural households is studied by I
subjective equilibrium model which also accounts for the household's
demographic structure. The model becomes a potent tool for integrating
the economic and demographic behaviour of the household, since issues
such as the value of children can be approached in a reality
maximization framework and furthermore, such values call be causally
rellted to the variance in measured fertility among different households
(or Socioeconomic groups). For example, the low marginal productivity
contribution of children in tenant (and small farm-size) households,
along with the low fertility control that prevails there, has been
combined In conforming the inverse fertility-endowments hypothesis,
which in this instance is based on labour market failure in periods of
peak agricultural labour demand. On the consumption side, on the other
hand, the demand for leisure and for other commodities is consistent
with the higher valuation of children, and thus higher fertility, in
tenant (and small farm-size) households, as compared to owner (and large
farm-size) households. The policy implications of such findings from a
household equilibrium model are rich
Quantum dots as a probe of fundamental physics: Deviation from exponential decay law
We explore a possibility of measuring deviation from the exponential decay
law in pure quantum systems. The power law behavior at late times of decay time
profile is predicted in quantum mechanics, and has been experimentally
attempted to detect, but with failures except a claim in an open system. It is
found that electron tunneling from resonance state confined in man-made atoms,
quantum dots, has a good chance of detecting the deviation and testing
theoretical predictions. How initial unstable state is prepared influences
greatly the time profile of decay law, and this can be used to set the onset
time of the power law at earlier times. Comparison with similar process of
nuclear alpha decay to discover the deviation is discussed, to explain why
there exists a difficulty in this case.Comment: 21 pages, 12 figure
Dinitrogen-Fixing Cyanobacteria in Microbial Mats of Two Shallow Coral Reef Ecosystems
Dinitrogen-fixing organisms in cyanobacterial mats were studied in two shallow coral reef ecosystems: La Reunion Island, southwestern Indian Ocean, Sesoko (Okinawa) Island, and northwestern Pacific Ocean. Rapidly expanding benthic miniblooms, frequently dominated by a single cyanobacterial taxon, were identified by microscopy and molecular tools. In addition, nitrogenase activity by these blooms was measured in situ. Dinitrogen fixation and its contribution to mat primary production were calculated using 15N2 and 13C methods. Dinitrogen-fixing cyanobacteria from mats in La Reunion and Sesoko showed few differences in taxonomic composition. Anabaena sp. among heterocystous and Hydrocoleum majus and Symploca hydnoides among nonheterocystous cyanobacteria occurred in microbial mats of both sites. Oscillatoria bonnemaisonii and Leptolyngbya spp. occurred only in La Reunion, whereas Hydrocoleum coccineum dominated in Sesoko. Other mats dominated by Hydrocoleum lyngbyaceum, Phormidium laysanense, and Trichocoleus tenerrimus occurred at lower frequencies. The 24-h nitrogenase activity, as measured by acetylene reduction, varied between 11 and 324 nmoles C2H2 reduced µg−1 Chl a. The highest values were achieved by heterocystous Anabaena sp. performed mostly during the day. Highest values for nonheterocystous cyanobacteria were achieved by H. coccineum mostly during the night. Daily nitrogen fixation varied from nine (Leptolyngbya) to 238 nmoles N2µg−1 Chl day−1 (H. coccineum). Primary production rates ranged from 1,321 (S. hydnoides) to 9,933 nmoles C µg−1 Chl day−1 (H. coccineum). Dinitrogen fixation satisfied between 5% and 21% of the nitrogen required for primary production.Ocean Development Sub-Committee of France–Japan S&T Cooperation; Mitsubishi cooperation; The Ministry of Education, Science, Sport, and Culture of Japan; Hanse Wissenschaftskolleg; Delmenhorst and Alexander-von-Humboldt Foundation; Bad Godesberg; Germany supported collaborative research on cyanobacterial diversit
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