87,512 research outputs found
Will the Kyoto Protocol Be Good for the Environment? Implications for Agriculture
Global warming or, more accurately, climate change remains a hotly debated issue in scientific, government and public circles. While the extent of the human contribution to climate change through greenhouse gas (GHG) emissions remains highly controversial, the scientific evidence of significant changes in climate per se appears to be mounting (Intergovernmental Panel on Climate Change, 2001). Since changes in climate typically will include greater variability in temperatures, more extreme weather events and changes in precipitation patterns as well as a general warming trend, there are significant risks for agriculture.(2) If human activity does turn out to have a significant causal effect on climate change, the Kyoto Protocol and other related multilateral environmental agreements appear to have the potential to reduce these risks. The Kyoto Protocol, however, leaves possible channels for increases in emissions or so-called carbon leakage.Environmental Economics and Policy,
Spectral signatures of photosynthesis II: coevolution with other stars and the atmosphere on extrasolar worlds
As photosynthesis on Earth produces the primary signatures of life that can
be detected astronomically at the global scale, a strong focus of the search
for extrasolar life will be photosynthesis, particularly photosynthesis that
has evolved with a different parent star. We take planetary atmospheric
compositions simulated by Segura, et al. (2003, 2005) for Earth-like planets
around observed F2V and K2V stars, modeled M1V and M5V stars, and around the
active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as
well as very low O2 content in case anoxygenic photosynthesis dominates. We
calculate the incident spectral photon flux densities at the surface of the
planet and under water. We identify bands of available photosynthetically
relevant radiation and find that photosynthetic pigments on planets around F2V
stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in
the NIR, in bands at 0.93-1.1 microns, 1.1-1.4 microns, 1.5-1.8 microns, and
1.8-2.5 microns. In addition, we calculate wavelength restrictions for
underwater organisms and depths of water at which they would be protected from
UV flares in the early life of M stars. We estimate the potential productivity
for both surface and underwater photosynthesis, for both oxygenic and
anoxygenic photosynthesis, and for hypothetical photosynthesis in which longer
wavelength, multi-photosystem series are used.Comment: 59 pages, 4 figures, 4 tables, forthcoming in Astrobiology ~March
200
Piezoelectric resonance in Rochelle salt: the contribution of diagonal strains
Within the framework of two-sublattice Mitsui model with taking into account
the shear strain and the diagonal strains and
, a dynamic dielectric response of Rochelle salt X-cuts is
considered. Experimentally observed phenomena of crystal clamping by high
frequency electric field, piezoelectric resonance and microwave dispersion are
described. It is shown that the lowest resonant frequency is always associated
with the shear modeComment: 17 pages, 6 figure
Gas-liquid mass transfer with parallel reversible reactions—III. Absorption of CO2 into solutions of blends of amines
A numerical method developed by Versteeg (1989, Chem. Engng Sci.44, 2295–2310; 1990, Chem. Engng Sci.45, in press) is applied to the absorption of Co2 into solutions of blends amines. The experimental results of Critchfield and Rochelle (1987) are evaluated with the numerical model. It is shown that a rigorous numerical solution of the differential equations describing the mass transfer gives more insight into the actual process than analytical approximations based on a reduction of the number of reactions by neglecting or lumping reactions
Influence of external factors on dielectric permittivity of Rochelle salt: humidity, annealing, stresses, electric field
The present work contains results of experimental investigation of external
factors, such as dessicating/wetting, thermal annealing, uniaxial and
hydrostatic pressures on dielectric permittivity of Rochelle salt crystals. The
obtained results are compared with available literature data. A conslusion is
made that the dispersion of experimental data can be attributed to internal
polar point defects in crystals and to influence of storage conditions. The
obtained results are analyzed within the phenomenological Landau approach
Major physical characteristics of Rochelle salt: the role of thermal strains
We compare the results for the related to the shear strain \epsilon_4
physical characteristics of Rochelle salt obtained within the recently
developed modified two-sublattice Mitsui model that takes into account the
strain \epsilon_4 and the diagonal components of the strain tensor \epsilon_1,
\epsilon_2, \epsilon_3 with the results of the previous modification of the
Mitsui model with the strain \epsilon_4 only. Within the framework of the model
with the diagonal (thermal expansion) strains, we also reexamine the effects of
the longitudinal electric field E_1 on the dielectric properties of Rochelle
salt.Comment: 10 pages, 11 figure
Open secrets
The law of trade secrets is often conceptualized in bilateral terms, as creating and enforcing rights between trade secret owners, on the one hand, and misappropriators on the other hand. This paper, a chapter in a forthcoming collection on the law of trade secrets, argues that trade secrets and the law that guards them can serve structural and institutional roles as well. Somewhat surprisingly, given the law’s focus on secrecy, among the institutional products of trade secrets law are commons, or managed openness: environments designed to facilitate the structured sharing of information. The paper illustrates with examples drawn from existing literature on cuisine, magic, and Internet search.
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