3,568 research outputs found
Carbon Dynamics and Land-Use Choices: Building a Regional-Scale Multidisciplinary Model
Policy enabling tropical forests to approach their potential contribution to global-climate-change mitigation requires forecasts of land use and carbon storage on a large scale over long periods. In this paper, we present an integrated modeling methodology that addresses these needs. We model the dynamics of the human land-use system and of C pools contained in each ecosystem, as well as their interactions. The model is national scale, and is currently applied in a preliminary way to Costa Rica using data spanning a period of over fifty years. It combines an ecological process model, parameterized using field and other data, with an economic model, estimated using historical data to ensure a close link to actual behavior. These two models are linked so that ecological conditions affect land-use choices and vice versa. The integrated model predicts land use and its consequences for C storage for policy scenarios. These predictions can be used to create baselines, reward sequestration, and estimate the value in both environmental and economic terms of including C sequestration in tropical forests as part of the efforts to mitigate global climate change. The model can also be used to assess the benefits from costly activities to increase accuracy and thus reduce errors and their societal costs.carbon, sequestration, climate change, land use, modelling
Interaction of temperature and CO2 enrichment on soybean : Photosynthesis and seed yield
Seed yield and photosynthetic responses of soybean (Gtycine mnx L. Met. ,Ransom')
were studied in growth chambers at day/night temperatures of 18/12,22/16, and 26/20'C
and atmospheric CO, concentrations of 350, 6i5 and 1000 pL L-1. No seeds were produced at 18/12°C within any of the CO2 concentrations. Numbers of pods and seeds increased with increasing temperature and CO2 levels. Carbon dioxide enrichment increased seed yield of soybean grown at moderately cool temperatures. This increase was associated with an increase in net photosynthetic rate. Leaf photosynthesis
in response to CO2 enrichment increased more at 22/16°C than at 26/20°C. Increases in, temperature and CO2 levels enhanced total growth of plants but hastened senescence of leaves. The extended photosynthetic capacity at cool temperatures did not result in allocating more dry matter to developing pods. CO2 enrichment at 26/20°C resulted in greater seed yield increases than CO2 enrichment at lower temperatures
Remarkably robust and correlated coherence and antiferromagnetism in (CeLa)CuGe
We present magnetic susceptibility, resistivity, specific heat, and
thermoelectric power measurements on (CeLa)CuGe single
crystals (0 1). With La substitution, the antiferromagnetic
temperature is suppressed in an almost linear fashion and moves below
0.36 K, the base temperature of our measurements for 0.8. Surprisingly, in
addition to robust antiferromagnetism, the system also shows low temperature
coherent scattering below up to 0.9 of La, indicating a small
percolation limit 9 of Ce that separates a coherent regime from a
single-ion Kondo impurity regime. as a function of magnetic field was
found to have different behavior for 0.9. Remarkably,
at = 0 was found to be linearly proportional to . The
jump in the magnetic specific heat at as a function of
for (CeLa)CuGe follows the theoretical prediction
based on the molecular field calculation for the = 1/2 resonant level
model
Aseptic meningitis in a patient taking etanercept for rheumatoid arthritis: a case report
Background \ud
We report a case of a 53 year old lady recently commenced on etanercept, an anti-TNF (tumour necrosis factor) therapy for rheumatoid arthritis presenting with \ud
confusion, pyrexia and an erythematous rash. \ud
\ud
Case presentation \ud
A lumbar puncture was highly suggestive of bacterial meningitis, but CSF cultures produced no growth, and polymerase chain reactions (PCR) for all previously reported bacterial, fungal and viral causes of meningitis were negative. \ud
\ud
Conclusions \ud
This case report describes aseptic meningitis as a previously unreported complication of etanercept therapy, and serves as a reminder of the rare but potentially lifethreatening risk of serious infections in patients taking anti-TNF therapy for a variety of conditions
Analysis of magnetization and a spin state crossover in the multiferroic CaCoMnO
Ca_3Co_{2-x}Mn_xO_6 (x ~ 0.96) is a multiferroic with spin-chains of
alternating Co(2+) and Mn(4+) ions. The spin state of Co(2+) remains
unresolved, due to a discrepancy between high temperature X-ray absorption
(S=3/2) and low temperature neutron (S=1/2) measurements. Using a combination
of magnetic modeling and crystal-field analysis, we show that the existing low
temperature data cannot be reconciled within a high spin scenario by invoking
spin-orbit or Jahn-Teller distortions. To unify the experimental results, we
propose a spin-state crossover with specific experimental predictions.Comment: 4 pages, 3 figure
A Study of Lyman-Alpha Quasar Absorbers in the Nearby Universe
Spectroscopy of ten quasars obtained with the Goddard High Resolution
Spectrograph (GHRS) of the Hubble Space Telescope (HST) is presented. A
clustering analysis reveals an excess of nearest neighbor line pairs on
velocity scales of 250-750 km/s at a 95-98% confidence level. The hypothesis
that the absorbers are randomly distributed in velocity space can be ruled out
at the 99.8% confidence level. No two-point correlation power is detected (xi <
1 with 95% confidence). Lyman-alpha absorbers have correlation amplitudes on
scales of 250-500 km/s at least 4-5 times smaller than the correlation
amplitude of bright galaxies. A detailed comparison between absorbers in nearby
galaxies is carried out on a limited subset of 11 Lyman- alpha absorbers where
the galaxy sample in a large contiguous volume is complete to M_B = -16.
Absorbers lie preferentially in regions of intermediate galaxy density but it
is often not possible to uniquely assign a galaxy counterpart to an absorber.
This sample provides no explicit support for the hypothesis that absorbers are
preferentially associated with the halos of luminous galaxies. We have made a
preliminary comparison of the absorption line properties and environments with
the results of hydrodynamic simulations. The results suggest that the
Lyman-alpha absorbers represent diffuse or shocked gas in the IGM that traces
the cosmic web of large scale structure. (abridged)Comment: 36 pages of text, 15 figures, 4 tables, 36 file
Gauge Theories with Cayley-Klein and Gauge Groups
Gauge theories with the orthogonal Cayley-Klein gauge groups and
are regarded. For nilpotent values of the contraction
parameters these groups are isomorphic to the non-semisimple Euclid,
Newton, Galilei groups and corresponding matter spaces are fiber spaces with
degenerate metrics. It is shown that the contracted gauge field theories
describe the same set of fields and particle mass as gauge
theories, if Lagrangians in the base and in the fibers all are taken into
account. Such theories based on non-semisimple contracted group provide more
simple field interactions as compared with the initial ones.Comment: 14 pages, 5 figure
Pro-inflammatory flagellin proteins of prevalent motile commensal bacteria are variably abundant in the intestinal microbiome of elderly humans
Peer reviewedPublisher PD
Inhibition of Tendon Cell Proliferation and Matrix Glycosaminoglycan Synthesis by Non-Steroidal Anti-Inflammatory Drugs in vitro
The purpose of this study was to investigate the effects of some commonly used non-steroidal anti-inflammatory drugs (NSAIDs) on human tendon. Explants of human digital flexor and patella tendons were cultured in medium containing pharmacological concentrations of NSAIDs. Cell proliferation was measured by incorporation of 3H-thymidine and glycosaminoglycan synthesis was measured by incorporation of 35S-Sulphate. Diclofenac and aceclofenac had no significant effect either on tendon cell proliferation or glycosaminoglycan synthesis. Indomethacin and naproxen inhibited cell proliferation in patella tendons and inhibited glycosaminoglycan synthesis in both digital flexor and patella tendons. If applicable to the in vivo situation, these NSAIDs should be used with caution in the treatment of pain after tendon injury and surgery
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