Uncertainties of predictions of future atmospheric CO2 concentrations

Linear carbon cycle models, tuned to reproduce the CO2 increase observed at Mauna Loa, independently of their individual assumptions, predict almost identical CO2 concentration trends for fossil energy scenarios assuming a slightly increasing production in the next few decades. The basic information for such prognoses therefore is the airborne fraction observed over the last 20 years. Uncertainties in this quantity are due to possible errors in the estimate of fossil fuel consumption and the corresponding CO2 emission, possible natural fluctuations in the baseline CO2 level, and uncertainties regarding the biospheric CO2 input and uptake as a result of deforestation and reforestation and land management. Depending on different assumptions the effective airborne fraction, defined as the ratio of CO2 increase due to fossil fuel CO2 alone to the integrated CO2 production, might be as low as 0.38 or as high as 0.72, compared to the apparent airborne fraction of 0.55. The effective airborne fraction derived from carbon cycle models, considering only the CO2 uptake by the ocean, lies in the range 0.60–0.70. A value as low as 0.40 seems therefore highly improbable. A high biospheric anthropogenic CO2 input therefore must have been accompanied by a high CO2 fertilization effect. Model considerations, however, are not in contradiction with a high biospheric input with the maximum production before 1958, which also would imply low preindustrial CO2 concentrations in the range 270–280 ppm as reported recently

High quality RNA from multiple brain regions simultaneously acquired by laser capture microdissection

<p>Abstract</p> <p>Background</p> <p>Laser capture microdissection enables the isolation of single cells or small cell groups from histological sections under direct microscopic observation. Combined with quantitative PCR or microarray, it is a very powerful approach for studying gene expression profiles in discrete cell populations. The major challenge for such studies is to obtain good quality RNA from small amounts of starting material.</p> <p>Results</p> <p>We have developed a simple, flexible, and low-cost method for simultaneously producing RNA from discrete cell groups in embryonic day 15 mouse brain. In particular, we have optimized the following key steps in the procedure: staining, cryosectioning, storage of sections and harvesting of microdissected cells. We obtained the best results when staining 20 μm-thick sections with 1% cresyl violet in 70% ethanol and harvesting the microdissected tissue in RNA stabilization solution. In addition, we introduced three stop-points in the protocol which makes the tedious process of laser capture microdissection more flexible, without compromising RNA quality.</p> <p>Conclusion</p> <p>Using this optimized method, we have consistently obtained RNA of high quality from all four simultaneously microdissected cell groups. RNA integrity numbers were all above 8, and long cDNA fragments (> 1.2 kb) were successfully amplified by reverse transcription PCR from all four samples. We conclude that RNAs isolated by this method are well suited for downstream quantitative PCR or microarray studies.</p

Nuclear recoil measurements in Superheated Superconducting Granule detectors

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70Me$\!$V neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few ke$\!$V. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15-20$\mu$m in diameter will be discussed. For the first time, recoil energy thresholds of $\sim$1ke$\!$V have been measured.Comment: 7pages in Latex format, Preprint Bu-He 93/6 (University of Berne, Switzerland), four figures available upon request via [email protected] or [email protected]

Towards a representative reference for MRI-based human axon radius assessment using light microscopy

Non-invasive assessment of axon radii via MRI bears great potential for clinical and neuroscience research as it is a main determinant of the neuronal conduction velocity. However, there is a lack of representative histological reference data at the scale of the cross-section of MRI voxels for validating the MRI-visible, effective radius (reff). Because the current gold standard stems from neuroanatomical studies designed to estimate the bulk-determined arithmetic mean radius (rarith) on small ensembles of axons, it is unsuited to estimate the tail-weighted reff. We propose CNN-based segmentation on high-resolution, large-scale light microscopy (lsLM) data to generate a representative reference for reff. In a human corpus callosum, we assessed estimation accuracy and bias of rarith and reff. Furthermore, we investigated whether mapping anatomy-related variation of rarith and reff is confounded by low-frequency variation of the image intensity, e.g., due to staining heterogeneity. Finally, we analyzed the error due to outstandingly large axons in reff. Compared to rarith, reff was estimated with higher accuracy (maximum normalized-root-mean-square-error of reff: 8.5 %; rarith: 19.5 %) and lower bias (maximum absolute normalized-mean-bias-error of reff: 4.8 %; rarith: 13.4 %). While rarith was confounded by variation of the image intensity, variation of reff seemed anatomy-related. The largest axons contributed between 0.8 % and 2.9 % to reff. In conclusion, the proposed method is a step towards representatively estimating reff at MRI voxel resolution. Further investigations are required to assess generalization to other brains and brain areas with different axon radii distributions

Hypothesis on the Dual Origin of the Mammalian Subplate

The development of the mammalian neocortex relies heavily on subplate. The proportion of this cell population varies considerably in different mammalian species. Subplate is almost undetectable in marsupials, forms a thin, but distinct layer in mouse and rat, a larger layer in carnivores and big-brained mammals as pig, and a highly developed embryonic structure in human and non-human primates. The evolutionary origin of subplate neurons is the subject of current debate. Some hypothesize that subplate represents the ancestral cortex of sauropsids, while others consider it to be an increasingly complex phylogenetic novelty of the mammalian neocortex. Here we review recent work on expression of several genes that were originally identified in rodent as highly and differentially expressed in subplate. We relate these observations to cellular morphology, birthdating, and hodology in the dorsal cortex/dorsal pallium of several amniote species. Based on this reviewed evidence we argue for a third hypothesis according to which subplate contains both ancestral and newly derived cell populations. We propose that the mammalian subplate originally derived from a phylogenetically ancient structure in the dorsal pallium of stem amniotes, but subsequently expanded with additional cell populations in the synapsid lineage to support an increasingly complex cortical plate development. Further understanding of the detailed molecular taxonomy, somatodendritic morphology, and connectivity of subplate in a comparative context should contribute to the identification of the ancestral and newly evolved populations of subplate neurons

Two Alleles of NF-κB in the Sea Anemone Nematostella vectensis Are Widely Dispersed in Nature and Encode Proteins with Distinct Activities

BACKGROUND. NF-κB is an evolutionarily conserved transcription factor that controls the expression of genes involved in many key organismal processes, including innate immunity, development, and stress responses. NF-κB proteins contain a highly conserved DNA-binding/dimerization domain called the Rel homology domain. METHODS/PRINCIPAL FINDINGS. We characterized two NF-κB alleles in the sea anemone Nematostella vectensis that differ at nineteen single-nucleotide polymorphisms (SNPs). Ten of these SNPs result in amino acid substitutions, including six within the Rel homology domain. Both alleles are found in natural populations of Nematostella. The relative abundance of the two NF-κB alleles differs between populations, and departures from Hardy-Weinberg equilibrium within populations indicate that the locus may be under selection. The proteins encoded by the two Nv-NF-κB alleles have different molecular properties, in part due to a Cys/Ser polymorphism at residue 67, which resides within the DNA recognition loop. In nearly all previously characterized NF-κB proteins, the analogous residue is fixed for Cys, and conversion of human RHD proteins from Cys to Ser at this site has been shown to increase DNA-binding ability and increase resistance to inhibition by thiol-reactive compounds. However, the naturally-occurring Nematostella variant with Cys at position 67 binds DNA with a higher affinity than the Ser variant. On the other hand, the Ser variant activates transcription in reporter gene assays more effectively, and it is more resistant to inhibition by a thiol-reactive compound. Reciprocal Cys<->Ser mutations at residue 67 of the native Nv-NF-κB proteins affect DNA binding as in human NF-κB proteins, e.g., a Cys->Ser mutation increases DNA binding of the native Cys variant. CONCLUSIONS/SIGNIFICANCE. These results are the first demonstration of a naturally occurring and functionally significant polymorphism in NF-κB in any species. The functional differences between these alleles and their uneven distribution in the wild suggest that different genotypes could be favored in different environments, perhaps environments that vary in their levels of peroxides or thiol-reactive compounds.National Institutes of Health (CA047763); National Science Foundation (FP-91656101-0); Environmental Protection Agency (F5E11155); Conservation International Marine Management Area Science Program; Boston University (SPRInG grant); Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution; The Beacon Institute for Rivers and Estuaries; the J Seward Johnson Fund; Boston University (5 P42 ES07381

Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics

The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected

Distribution of Hydrogen Peroxide In the Northwest Pacific Ocean

[1] Hydrogen peroxide (H2O2) is a reactive oxygen intermediate involved in the cycling of metals and dissolved organic matter. Because little is known of its distribution in the North Pacific Ocean, we determined H2O2 in surface waters continuously and obtained vertical profiles at nine stations during a cruise from Japan to Hawaii. Surface water H2O2 varied from less than 10 to more than 250 nmol dm(-3). A diel cycle in surface water H2O2 (similar to 25 nmol dm(-3)) was observed only on one day during the monthlong cruise. This is contrary to expectations based on the usual assumption of photo-production as the dominant input of H2O2. Experiments were also conducted during the cruise to examine both photo-production and dark decay. The net rate of photo-production at a station near Hawaii was determined to be 8 nmol dm(-3) h(-1), similar to rates reported for the central Atlantic Ocean and Antarctic. However, this maximum estimate of photo-production is also similar to probable rates of H2O2 input by other mechanisms ( biological production and rain). The pseudo-first-order rate constant for dark decay varied from 0.1 to 0.2 d(-1), which is toward the low end of previous reports of H2O2 decay rates, and was observed to increase proportionately to the dissolved organic carbon concentration. Taken together, these results suggest that photo-production of H2O2 in open ocean waters may be less important than previously thought and therefore H2O2 is likely less of an indicator of the photo-chemical reactivity of surface waters than hoped for. Furthermore, we observed that the H2O2 inventory for the upper 200 m of the water column has a maximum at midlatitudes. We suggest that this results from diminished inputs at high latitude as well as increased decay rates at low latitudes

The three main monotheistic religions and gm food technology: an overview of perspectives

Abstract Background Public acceptance of genetically modified crops is partly rooted in religious views. However, the views of different religions and their potential influence on consumers' decisions have not been systematically examined and summarized in a brief overview. We review the positions of the Judaism, Islam and Christianity – the three major monotheistic religions to which more than 55% of humanity adheres to – on the controversies aroused by GM technology. Discussion The article establishes that there is no overarching consensus within the three religions. Overall, however, it appears that mainstream theology in all three religions increasingly tends towards acceptance of GM technology per se, on performing GM research, and on consumption of GM foods. These more liberal approaches, however, are predicated on there being rigorous scientific, ethical and regulatory scrutiny of research and development of such products, and that these products are properly labeled. Summary We conclude that there are several other interests competing with the influence exerted on consumers by religion. These include the media, environmental activists, scientists and the food industry, all of which function as sources of information and shapers of perception for consumers