Stolen Future, Broken Present

This book argues that climate change has a devastating effect on how we think about the future. Once several positive feedback loops in Earth’s dynamic systems, such as the melting of the Arctic icecap or the drying of the Amazon, cross the point of no return, the biosphere is likely to undergo severe and irreversible warming. Nearly everything we do is premised on the assumption that the world we know will endure into the future and provide a sustaining context for our activities. But today the future of a viable biosphere, and thus the purpose of our present activities, is put into question. A disappearing future leads to a broken present, a strange incoherence in the feel of everyday life. We thus face the unprecedented challenge of salvaging a basis for our lives today. That basis, this book argues, may be found in our capacity to assume an infinite responsibility for ecological disaster and, like the biblical Job, to respond with awe to the alien voice that speaks from the whirlwind. By owning disaster and accepting our small place within the inhuman forces of the biosphere, we may discover how to live with responsibility and serenity whatever may come

Stolen future, broken present: The human significance of climate change

This book argues that climate change has a devastating effect on how we think about the future. Once several positive feedback loops in Earth’s dynamic systems, such as the melting of the Arctic icecap or the drying of the Amazon, cross the point of no return, the biosphere is likely to undergo severe and irreversible warming.Nearly everything we do is premised on the assumption that the world we know will endure into the future and provide a sustaining context for our activities. But today the future of a viable biosphere, and thus the purpose of our present activities, is put into question. A disappearing future leads to a broken present, a strange incoherence in the feel of everyday life.We thus face the unprecedented challenge of salvaging a basis for our lives today. That basis, this book argues, may be found in our capacity to assume an infinite responsibility for ecological disaster and, like the biblical Job, to respond with awe to the alien voice that speaks from the whirlwind. By owning disaster and accepting our small place within the inhuman forces of the biosphere, we may discover how to live with responsibility and serenity whatever may come

Warm Cores around Regions of Low-Mass Star Formation

Warm cores (or hot corinos) around low-mass protostellar objects show a rich chemistry with strong spatial variations. This chemistry is generally attributed to the sublimation of icy mantles on dust grains initiated by the warming effect of the stellar radiation. We have used a model of the chemistry in warm cores in which the sublimation process is based on extensive laboratory data; these data indicate that sublimation from mixed ices occurs in several well-defined temperature bands. We have determined the position of these bands for the slow warming by a solar-mass star. The resulting chemistry is dominated by the sublimation process and by subsequent gas-phase reactions; strong spatial and temporal variations in certain molecular species are found to occur, and our results are, in general, consistent with observational results for the well-studied source IRAS 16293-2422. The model used is similar to one that describes the chemistry of hot cores. We infer that the chemistry of both hot cores and warm cores may be described by the same model (suitably adjusted for different physical parameters).Comment: 11 pages, 5 figures, 2 tables. Accepted by MNRA

The tectono-metamorphic evolution of the Rhodope Massif, Bulgaria

In recent years the Rhodope Massif has risen in prominence due to the discovery of microdiamond in garnet from metapelites in the Greek Rhodope Mts., establishing the region as a rare UHP province. This study is the first to establish that the UHP conditions continue through to Bulgaria, owing to the discovery of a microdiamond inclusion in garnet from metapelite in the vicinity of the town of Chepelare in the Bulgarian Central Rhodope Mts. This UHP metapelite outcrops within the Chepelare Shear zone (CSZ), a ‘melange’ of meta-igneous and meta-sedimentary rocks located on the edge of the Variscan Arda dome, one of three metamorphic core complexes that dominate the regional geology. Through a combination of petrographical and geochemical analysis, the metamorphic conditions experienced by these UHP samples have been reconstructed. Two populations of metabasic units in the Central Rhodope Mts. were identified in this study; one within the melange units of the CSZ, and one as boudins in orthogneiss overlying the CSZ. The boudins are shown to be retrogressed eclogites with a suprasubduction zone origin unrelated to the metabasic units within the CSZ. Correlations are observed with Neoproterozoic/Ordovician metabasic samples previously reported from the Eastern Rhodope Mts., which represent remnants of the Variscan Orogeny in this region. Metabasic melange samples within the CSZ instead have an N-MORB affinity, and display no evidence of a shared P-T history with the UHP metapelites. Sm-Nd garnet dating of the metapelites from the CSZ performed in this study indicates a Late Cretaceous age for the UHP metamorphic event. This is significantly younger than previously reported ages, and suggests a formation history associated with the northwards subduction of the Vardar Ocean beneath the Moesian Platform during the Late Mesozoic. The present day structure of the massif is the result of complex Cenozoic tectonics following post orogenic extension and formation of the metamorphic core complexes that are observed across the Rhodope Massif

The N-terminal TOG domain of Arabidopsis MOR1 modulates affinity for microtubule polymers

Microtubule-associated proteins of the highly conserved XMAP215/Dis1 family promote both microtubule growth and shrinkage, and move with the dynamic microtubule ends. The plant homologue, MOR1, is predicted to form a long linear molecule with five N-terminal TOG domains. Within the first (TOG1) domain, the mor1-1 leucine to phenylalanine (L174F) substitution causes temperature-dependent disorganization of microtubule arrays and reduces microtubule growth and shrinkage rates. By expressing the two N-terminal TOG domains (TOG12) of MOR1, both in planta for analysis in living cells and in bacteria for in vitro microtubule-binding and polymerization assays, we determined that the N-terminal domain of MOR1 is crucial for microtubule polymer binding. Tagging TOG12 at the N-terminus interfered with its ability to bind microtubules when stably expressed in Arabidopsis or when transiently overexpressed in leek epidermal cells, and impeded polymerase activity in vitro. In contrast, TOG12 tagged at the C-terminus interacted with microtubules in vivo, rescued the temperature-sensitive mor1-1 phenotype, and promoted microtubule polymerization in vitro. TOG12 constructs containing the L174F mor1-1 point mutation caused microtubule disruption when transiently overexpressed in leek epidermis and increased the affinity of TOG12 for microtubules in vitro. This suggests that the mor1-1 mutant protein makes microtubules less dynamic by binding the microtubule lattice too strongly to support rapid plus-end tracking. We conclude from our results that a balanced microtubule affinity in the N-terminal TOG domain is crucial for the polymerase activity of MOR1

The cometary composition of a protoplanetary disk as revealed by complex cyanides

Observations of comets and asteroids show that the Solar Nebula that spawned our planetary system was rich in water and organic molecules. Bombardment brought these organics to the young Earth's surface, seeding its early chemistry. Unlike asteroids, comets preserve a nearly pristine record of the Solar Nebula composition. The presence of cyanides in comets, including 0.01% of methyl cyanide (CH3CN) with respect to water, is of special interest because of the importance of C-N bonds for abiotic amino acid synthesis. Comet-like compositions of simple and complex volatiles are found in protostars, and can be readily explained by a combination of gas-phase chemistry to form e.g. HCN and an active ice-phase chemistry on grain surfaces that advances complexity[3]. Simple volatiles, including water and HCN, have been detected previously in Solar Nebula analogues - protoplanetary disks around young stars - indicating that they survive disk formation or are reformed in situ. It has been hitherto unclear whether the same holds for more complex organic molecules outside of the Solar Nebula, since recent observations show a dramatic change in the chemistry at the boundary between nascent envelopes and young disks due to accretion shocks[8]. Here we report the detection of CH3CN (and HCN and HC3N) in the protoplanetary disk around the young star MWC 480. We find abundance ratios of these N-bearing organics in the gas-phase similar to comets, which suggests an even higher relative abundance of complex cyanides in the disk ice. This implies that complex organics accompany simpler volatiles in protoplanetary disks, and that the rich organic chemistry of the Solar Nebula was not unique.Comment: Definitive version of the manuscript is published in Nature, 520, 7546, 198, 2015. This is the author's versio