Degradation and forgone removals increase the carbon impact of intact forest loss by 626%

Intact tropical forests, free from substantial anthropogenic influence, store and sequester large amounts of atmospheric carbon but are currently neglected in international climate policy. We show that between 2000 and 2013, direct clearance of intact tropical forest areas accounted for 3.2% of gross carbon emissions from all deforestation across the pantropics. However, full carbon accounting requires the consideration of forgone carbon sequestration, selective logging, edge effects, and defaunation. When these factors were considered, the net carbon impact resulting from intact tropical forest loss between 2000 and 2013 increased by a factor of 6 (626%), from 0.34 (0.37 to 0.21) to 2.12 (2.85 to 1.00) petagrams of carbon (equivalent to approximately 2 years of global land use change emissions). The climate mitigation value of conserving the 549 million ha of tropical forest that remains intact is therefore significant but will soon dwindle if their rate of loss continues to accelerate

Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms

While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO₂-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (Kcatᶜ), oxygenation (Kcatᵒ), Michaelis constants (K m) for CO₂ (K C) and O₂ (K O), and specificity for CO₂ over O₂ (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in KC (23-68 μM), SC/O (57-116mol mol⁻¹), and KO (413-2032 μM) relative to plant and algal Rubisco. The broad range of KC values mostly exceed those of C₄ plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat c for each diatom Rubisco showed less variation (2.1-3.7s⁻¹), thus averting the canonical trade-off typically observed between KC and kcatᶜ for plant Form I Rubisco. Uniquely, a negative relationship between KC and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily

Colorless States in Perturbative QCD: Charmonium and Rapidity Gaps

We point out that an unorthodox way to describe the production of rapidity gaps in deep inelastic scattering, recently proposed by Buchm\"uller and Hebecker, suggests a description of the production of heavy quark bound states which is in agreement with data. The approach questions the conventional treatment of the color quantum number in perturbative QCD.Comment: 14 pages, plain Latex, 9 postscript figures included. Uses epsf.sty. Postscript file of paper with figures also available at http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-919.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-919.ps.

Quantitative Tests of Color Evaporation: Charmonium Production

The color evaporation model simply states that charmonium production is described by the same dynamics as $D \bar D$ production, {\em i.e.}, by the formation of a colored $c \bar c$ pair. Its color happens to be bleached by soft final-state interactions. We show that the model gives a complete picture of charmonium production including low-energy production by proton, photon and antiproton beams, and high-energy production at the Tevatron and HERA. Our analysis includes the first next-to-leading-order calculation in the color evaporation model.Comment: 12 pages (with embedded figures), Latex2.09, uses epsf.sty and epsfig.sty. Z-compressed postscript version also available at http://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-942.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-942.ps.

Abundances of the elements in the solar system

A review of the abundances and condensation temperatures of the elements and their nuclides in the solar nebula and in chondritic meteorites. Abundances of the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New York: Springer-Verlag, p. 560-63

Relative Artin motives and the reductive Borel-Serre compactification of a locally symmetric variety

We introduce the notion of Artin motives and cohomological motives over a scheme X. Given a cohomological motive M over X, we consider the universal Artin motive mapping to M and denote it ω0X(M). We use this to define a motive

Optical studies on the red luminescence of InGaN epilayers

Photoluminescence, photoluminescence excitation and time-resolved photoluminescence studies were performed in a partially relaxed InGaN epilayer, and exhibiting a 3D growth mode at the surface. Two emission bands, a red (centred at ∼1.88 eV) and a blue (centred at ∼2.58 eV) were observed. In order to investigate their origin and their relation with the strain relaxation along the growth direction, the sample was etched. After etching, only an asymmetrical broad emission band centred at ∼2.15 eV was observed. The decrease of decay time and the increase of the band edge absorption energy with increasing monitored photon energy, along the red emission, are assigned to the effect of localization of excitons at potential minima, originated in compositional and strain inhomogeneities of the sample. Therefore, the blue shift observed on this band with an increase in temperature, is caused by the population of higher energy states. The large difference between the luminescence intensities, decay times and the thermal quenching of the red and blue (centred at ∼2.58 eV) band is also accounted for by the localization model. It is demonstrated that the luminescence observed after etching is a superposition of two bands, one originated from the InGaN film, and the other from the GaN underlayer. The large difference between absorption and emission energies, compared with those measured in the as-grown sample, within the same spectral region, indicates that this emission has a different origin. It is suggested that deep levels might be responsible for the luminescence observed after etching