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Mathematical models of long-term peatland development have been produced to analyse peatland behaviour. However, existing models ignore the mechanical processes that have the potential to provide important feedback. Here, we propose a one-dimensional model, MPeat, that couples mechanical, ecological and hydrological processes via poroelasticity theory, which couples fluid flow and solid deformation. Poroelasticity formulation in the MPeat is divided into two categories, fully saturated and unsaturated. To validate this formulation, we compare numerical solutions of the fully saturated case with analytical solutions of Terzaghi's problem. Two groups of MPeat simulations are run over 6,000 years using constant and variable climate, and the results are compared to those of two other peat growth models, DigiBog and the Holocene Peat Model. Under both climatic conditions, MPeat generates the expected changes in bulk density, active porosity and hydraulic conductivity at the transition from the unsaturated to the saturated zone. The range of values of peat physical properties simulated by MPeat shows good agreement with field measurement, indicating plausible outputs of the proposed model. Compared to the other peat growth models, the results generated by MPeat illustrate the importance of poroelasticity to the behaviour of peatland. In particular, the inclusion of poroelasticity produces shallower water table depth, accumulates greater quantities of carbon and buffers the effect of climate changes on water table depth and carbon accumulation rates. These results illustrate the importance of mechanical feedbacks on peatland ecohydrology and carbon stock resilience.

Gaseous impurities, such as O2, are expected to be present within CO2 captured for storage. This could stimulate microbial activity in a geological CO2 storage site which has the potential to lead to operational issues such as injection well blockages, corrosion and oil souring. A series of experiments were carried out to examine the effect of 10 ppm and 100 ppm O2 in an anoxic (CO2 or N2) atmosphere on microbial communities and microbial gas production in laboratory scale experiments. Experiments inoculated with sulphate reducing bacteria enrichments were compared to uninoculated controls. The results show that H2S production is delayed in a CO2 atmosphere compared to the N2 atmosphere. 100 ppm O2 in CO2 resulted in a spike of H2S production as well as greater bacterial biomass when compared to the 10 ppm O2 in CO2 atmosphere. The inoculated N2 experiments showed similar patterns in H2S production and biomass regardless of O2 concentration. These results suggest that a concentration of O2 lower than 100 ppm in CO2 could reduce the potential for microbial growth and H2S production in CO2 storage sites. CH4 production was observed in some microcosms subsequent to H2S production, highlighting the potential for microbial methanogenesis in the in CCS reservoirs.

Peatland carbon may enter long-term storage in sedimentary basins preserved as either coal or lignite. To understand the process by which this happens requires extrapolation of our understanding of...

The carbon sink potential of peatlands depends on the balance of carbon uptake by plants and microbial decomposition. The rates of both these processes will increase with warming but it remains unclear which will dominate the global peatland response. Here we examine the global relationship between peatland carbon accumulation rates during the last millennium and planetary-scale climate space. A positive relationship is found between carbon accumulation and cumulative photosynthetically active radiation during the growing season for mid- to high-latitude peatlands in both hemispheres. However, this relationship reverses at lower latitudes, suggesting that carbon accumulation is lower under the warmest climate regimes. Projections under Representative Concentration Pathway (RCP)2.6 and RCP8.5 scenarios indicate that the present-day global sink will increase slightly until around AD 2100 but decline thereafter. Peatlands will remain a carbon sink in the future, but their response to warming switches from a negative to a positive climate feedback (decreased carbon sink with warming) at the end of the twenty-first century.

Rapid population growth in South-East Asia has placed immense pressure upon lowland regions both to supply food and employment and space for residential, commercial and infrastructure development. This pressure has led to sites on tropical peatland previously considered unsuitable for development to be revisited. One such site, the KLIA2 terminal and runway, Kuala Lumpur International Airport which opened in May 2014 at a cost of 3.6 billion MYR has been beset by well documented subsidence problems. Coverage of the tropics by the Sentinel-1 satellite constellation presents an opportunity to monitor the ongoing subsidence at KLIA 2, identify potential knowledge gaps and help inform more sustainable infrastructure development in tropical peatland regions. Our results show that the ISBAS InSAR method produces reproducible ground deformation maps which can clearly identify the patterns of deformation across both urban infrastructure and adjacent rural plantations and tropical peat swamp. This is particularly well defined around the terminal building at KLIA-2 where different ground preparation and foundation design have resulted in stable terminal buildings and subsidence of surrounding pavement. Deformation is greatest in the runway area where alternate bands of uplift and subsidence presumably accompany the greatest loads associated with landing aircraft. In contrast, areas where peat replacement was the primary form of ground preparation, ground motion is stable, however this comes at high economic and environmental cost.

The Jurassic is an important period of global coal formation, including the development of several large coalfields in central Asia and northern China. Individual seams within these peatlands represent sustained periods of terrestrial carbon accumulation and a key environmental indicator attributed to this record is the rate of carbon accumulation. Determining the rate of carbon accumulation requires a measure of time contained within the coal and this study aimed at determining the rate via the identification of Milankovitch orbital cycles using spectral analysis. Spectral analyses of geophysical data from two thick coal seams, No. 43 (35.9 m) and No. 3 (13.2 m), of the Middle Jurassic of the southern Junggar coalfield were conducted to identify significant signals of variations in ash content. The results showed that the variations in ash content of the coal showed spatial cycles at 0.2, 0.7 and 1.1 m−1, which were interpreted to represent 123 ka (eccentricity), 37.1 ka (obliquity), and 21.2 ka (precession) orbital periodicities, respectively. Using this timeframe, the depositional time of the No. 43 and No. 3 coal seams were calculated to be 876–970 and 322–357 ka, respectively. In combination with an understanding of carbon loss during coalification, the carbon accumulation rates of these Middle Jurassic peatlands were calculated to be 58.6–64.9 and 60.3–66.8 g C m−2 a−1 for the No. 43 and No. 3 coal seams, respectively. Given that the net primary productivity ( NPP ) was 4.3 times the value of the carbon accumulation in a mid-latitude region of 40°–45°N, an NPP of 251.8–279.1 and 259.1–287.1 g C m−2 a−1 was calculated for the No. 43 and No. 3 coal seams, respectively. In the context of the same paleolatitude (40°–45°N) and peat type, the NPP values of the Middle Jurassic strata in the study area were higher than those of the peatlands of the Holocene and Permian, and were similar to the NPP values of Early Cretaceous peatlands. Considering the NPP of a peatland is predominantly controlled by atmospheric CO2 and O2 levels and temperature, the lower content of CO2 and an excessive O2 level in the temporal atmosphere would lead to a decrease in peatland NPP . Therefore, it is inferred that the CO2 level during the Middle Jurassic was higher than that of the icehouse Permian and Holocene periods, and it was similar to the CO2 level of the greenhouse Cretaceous period. The results are consistent with the global CO2 variation curve of Berner. In conclusion, Milankovitch orbital cycles calculated from geophysical logs can be used to infer the NPP of temporal peatlands during different geological periods, based on which the deep-time paleoclimates can be analyzed.

Tropical peatlands represent an important source of carbon dioxide (CO 2 ) and methane (CH 4 ) to the atmosphere. However, we do not know where in the peat profile these gases are produced and how controlling factors, such as substrate quality, which can vary substantially with peat age, and anoxic-oxic conditions, interact to determine production rates. To address this knowledge gap, this study investigated if substrate limitation of CO 2 and CH 4 production differs under anoxic-oxic peat conditions using entire peat profiles, from tropical peatlands in Panama. We determined the variation in peat organic chemistry through stratigraphic profiles using tetramethylammonium-pyrolysis-gas chromatography-mass spectrometry (TMAH-Py-GC/MS). To explore how variation in peat organic chemistry through the depth profile impacted on CO 2 and CH 4 production rates under anoxic-oxic conditions we carried out a series of incubation experiments. The TMAH-Py-GC/MS analysis showed high concentrations of long chain fatty acids (>C 20 ) in surface peat, and variation in the distribution of the lignin monomers through the peat profile. Both anoxic CH 4 and CO 2 production was greatest from the surface of the peat profile with surface peat accounting for 92 ± 1.7 and 54 ± 2.9% of the cumulative CH 4 and CO 2 production, respectively. The high CO 2 and CH 4 production rate under anoxic conditions, in surface peat, was strongly related to greater concentrations of lignin, but also long chain fatty acids and polysaccharides, in this section of the peat profile. As expected, CH 4 production decreased, and became decoupled from peat organic chemistry, following peat aeration. In contrast, aeration dramatically increased CO 2 emissions throughout the entire peat profile. This demonstrates that the recalcitrance of buried peat does not protect C stocks in tropical peatlands, if their water tables are lowered in response to drainage or prolonged drought. In conclusion, our work highlight that information on both labile substrate availability and water table fluctuation are needed to predict CO 2 and CH 4 fluxes from tropical peatlands.

Roofing slate has its own regulations and standards, as with other natural stones. The two main markets for roofing slate are USA/Canada and Europe. Given the very long tradition of slate mining in these two areas, it is no surprise that the first regulations for roofing slate were developed there. In the USA and Canada, the technical requirements are compiled in the standard ASTM C406 , while in Europe test methods and requirements are defined in EN 12326. There are also standards from China (GB/T 18600) and India (IS 6250), the emerging production countries in the slate market. This review article analyses and compares the current test methods for roofing slate. Also, new test methods are proposed in order to complement the information of the official standards.

Despite widespread evidence for atmospheric dust deposition prior to the Quaternary, quantitative rate data remains sparse. As dust influences both climate and biological productivity, the absence of quantitative dust data limits the comprehensiveness of models of pre-Quaternary climate and biogeochemical cycles. Here, we propose that inorganic matter contained in coal primarily records atmospheric dust deposition. To test this, we use the average concentration of inorganic matter in Permian coal to map global patterns and deposition rates of atmospheric dust over Pangea. The dust accumulation rate is calculated assuming Permian peat carbon accumulation rates in temperate climates were similar to Holocene rates and accounting for the loss of carbon during coalification. Coal-derived rates vary from 0.02 to 25 g m− 2 year− 1, values that fall within the present-day global range. A well-constrained East–West pattern of dust deposition corresponding to expected palaeoclimate gradients extends across Gondwana with maximum dust deposition rates occurring close to arid regions. A similar pattern is partially defined over the northern hemisphere. Patterns are consistent with the presence of two large global dust plumes centred on the tropics. The spatial patterns of dust deposition were also compared to dust cycle simulations for the Permian made with the Community Climate System Model version 3 (CCSM3). Key differences between the simulations and the coal data are the lack of evidence for an Antarctic dust source, higher than expected dust deposition over N and S China and greater dust deposition rates over Western Gondwana. This new coal-based dust accumulation rate data expands the pre-Neogene quantitative record of atmospheric dust and can help to inform and validate models of global circulation and biogeochemical cycles over the past 350 Myr.

Litter decomposition is an important control on carbon accumulation in tropical peatlands. We investigated the contribution of different litter tissues from two peatland tree species (Raphia taedigera and Campnosperma panamensis) to peat formation in four lowland tropical peatlands in the Republic of Panama. Leaves, stems, and roots decomposed at different rates; with roots being the slowest to decompose among tissues. The position of litter in the peat profile strongly influenced the decomposition rate of all tissue types. Roots decomposed up to five times faster at the surface than at 50 cm depth. Molecular characterization of litter and peat profiles by tetramethylammonium-pyrolysis–gas chromatography–mass spectrometry (TMAH-Py-GC/MS) revealed that the peat is formed predominantly of decomposed roots and stems, as indicated by the high lignin, low methylated fatty acids and carbohydrate concentrations in these litter types. Taken together, these data demonstrate that roots play a fundamental role in the formation of lowland Neotropical peatlands.

Abundant oil prone coal (Type III kerogen) deposits are preserved within the high latitude, middle Palaeocene, Todalen member of the Central Tertiary Basin, Spitsbergen Island, Norwegian Arctic. The coals (Svea, Longyear, Svarteper and Askeladden seams) have been subjected to only minor previous geochemical characterisation. Focussing upon the Longyear seam, this paper characterises the present, prospective and economic oil potential of the Svalbard coals. Organic biomarker parameters, Fe–S chemistry and coal maceral analysis are then applied to understand the provenance and environmental origins of this unusual source rock. The upper Todalen Mbr. coals (Longyear, Svarteper and Askeladden seams) have significantly more oil potential than the Lower Svea seams with estimated retortion yields of 170–190 kg/tonne vs. 24 kg/tonne respectively. The Longyear seam exhibits relatively high HI values (ca. 300–400 mg/g TOC) consistent with a hydrogen rich mixed Type II/III kerogen source. Greatest oil potential is shown to be favoured by formation within a fen environment, with high bacterial degradation (> 100 μg/g TOC hopanes), marine influence (> 0.5 wt.% sulfur, Fe/S < 0.9) and the unique temperate high latitude Palaeocene climate of Svalbard leading to preservation of hydrogen rich organic matter via organo-sulfur bond formation.

In April 2012 the National Health Service in England introduced the Trauma Network system with the aim of improving the quality of trauma care. In this study we wished to determine how the introduction of the Trauma network has affected patient flow, hospital finances and orthopaedic trauma training across our region.The overall pattern of trauma distribution was not greatly affected, reflecting the relative rarity of major trauma in the UK.A small decrease in the total number of operations performed by trainees was noted in our region. Trainees at units designated as Major Trauma Centres gained slightly more operative experience in trauma procedures overall, and specifically in those associated with high energy, such as long bone nail insertion and external fixation procedures. However, there have been no significant changes in this pattern since the introduction of the Trauma Networks. Falling operative numbers presents a challenge for delivering high quality training within a surgical training programme, and each case should be seen as a vital educational opportunity.Best practice tariff targets for trauma were delivered for 99% of cases at our MTCs. Future audit and review to analyse the evolving role of the MTCs is desirable.

In this paper the authors consider two contrasting viewpoints; Complex responsive processes which deal with interactions in the present, and complex adaptive systems which focus on learning through the production of what are called mental models. The paper shows that rather than being contradictory, these viewpoints are – at least in some respects - complementary. From the resulting perspective we are able to identify qualitative synergies between the two approaches. Complex responsive processes involve reflections on interactions that take place in time. But you cannot stop time so these present reflections always refer back to a present now gone. Complex adaptive systems are analytic tools. They are not explicitly in the present or in time at all, but they shape our thoughts and actions which are in the present. They shape how people behave, respond and think in a context. In this way people can combine, or reorganise, the approach to complex responsive processes and complex adaptive systems to show how humans address the complex notions of our world.

Accelerated carbonation of alkaline wastes such as steelmaking slag offers the potential to combine waste valorisation with climate change mitigation by utilising carbon dioxide (CO 2 ). One method of achieving this is through an indirect carbonation process to produce a marketable precipitated calcium carbonate (PCC), using ammonium salts to selectively extract calcium from steelmaking slag. Two unaddressed design parameters for a slag based plant differing from that of a traditional PCC plant are the effect of mineralogy on extraction efficiency when using a multicomponent, heterogeneous feed such as slag and the challenges raised by the resulting leachate chemistry. This paper presents petrographic textural observations on the effect of calcium leaching via ammonium chloride on individual grains of dicalcium silicate in three different widely unutilised steelmaking slags. These observations are then interpreted in conjunction with measured changes in solution leachate chemistry. The results indicate that although silica enriched regions form at the reaction front, the reaction continues into the core of the particle due to fracture propagation caused by volume reduction as calcium is extracted. Co-leaching of sulfur alongside calcium and the formation of precipitate in the leachate highlights potential engineering challenges when the process is scaled up due to fouling of process equipment. The main mineral phases in all untreated slags were found to be calcium silicates, predominantly dicalcium silicate (Ca 2 SiO 4 ). This was followed by a complex mixture of calcium/magnesium-wustite (CaFeMnMg)O type phases and srebrodolskite (Ca 2 Fe 2 O 5 (Ti, V)). Results indicate that calcium silicate is the more reactive component of BOS slag, while lime bound as (CaFeMnMg)O is most reactive in HMD and SS slags. Selectivity of the ammonium chloride solvent was high at 95–97% and efficiency of calcium extraction ranged between 25% and 39%.

This paper presents a combination of surface free energy testing techniques for aggregates and bitumen, with mechanical moisture-sensitivity assessment techniques for identification of compatible bitumen–aggregate combinations. Results from the surface free energy measurements and calculations were compared with data from the rolling bottle test and the saturation ageing tensile stiffness test in order to establish relationships amongst the three techniques. The mineralogical composition and microstructure of the aggregates were characterised using a mineral liberation analyser. For the same bitumen type, moisture sensitivity of mixtures containing limestone aggregates were found to be lower than mixtures containing granite aggregates. The presence of high amounts of quartz and feldspar (up to 50%) in the granite compared with almost none in limestone, and the significant amount of calcite in limestone (96% or more) versus none in granite were cited as possible reasons for the differences in performance of the two aggregate types. The porosity of the worst performing aggregates was higher than the best performing aggregate. The study concludes that moisture damage in the bituminous mixture is a function of the physico-chemical surface free energy properties of bitumen and aggregates as well as the mineralogical composition of aggregates.

The publishing success of E.L. James' Fifty Shades of Grey, a series with origins as Twilight fan fiction, has energised popular interest in the practice of writing fan fiction (or ‘fanfics’). Equally, however, the series' popularity has fuelled debate on the ethics of its commercial publication. This article highlights the divisive and polarising phenomenon of ‘pulling to publish’ in the Twilight fandom. ‘Pulling to publish’ refers to the process of rewriting and republishing for profit a work that was inspired by another's intellectual property, and collaboratively edited by unpaid volunteers – the majority of whom would have expected the edited work to be freely available in perpetuity. Among other relevant case studies, this article examines a critical instance of pseudonymous online protest, challenge and defence between James and another well-known fanfic writer, coinciding with the March 2011 announcement that Fifty Shades would be commercially published. Several critiques of fanfic commercialisation are contextualised by a critical reading of the ‘official’ publication history of Fifty Shades, revealing the incompatibility of two self-constructed fan identities: the faithful and the opportunistic.

A large body of international research has been done investigating best practice selection across many occupational groups, but there is relatively little research on developing selection methodology for entry to postgraduate training. Hitherto, various selection processes have been used, some of which relied heavily on patronage. Developments in Medical Education, including curriculum design, formal work-based place assessment, alongside the introduction of MMC (Modernizing Medical Careers) paved the way for significant change. Trauma and orthopedics in England is the last surgical specialty to adopt National Selection and did so first in 2013. This paper sets out that journey, the implementation of National selection in 2013, what has been learned, and our goals for the future.

This special issue comprising 14 articles emerged from the PAGES supported meeting: Holocene Circum Arctic Peatland Carbon Dynamics Community Wide Data Synthesis and Modeling Initiatives which took place from the 12 16 October 2013 in Bethlehem Pennsylvania. It is a precursor product of PAGES' C PEAT Working Group. ABSTRACT: Here we present results from the most comprehensive compilation of Holocene peat soil properties with associated carbon and nitrogen accumulation rates for northern peatlands. Our database consists of 268 peat cores from 215 sites located north of 45°N. It encompasses regions within which peat carbon data have only recently become available such as the West Siberia Lowlands the Hudson Bay Lowlands Kamchatka in Far East Russia and the Tibetan Plateau. For all northern peatlands carbon content in organic matter was estimated at 42 ± 3 (standard deviation) for Sphagnum peat 51 ± 2 for non Sphagnum peat and at 49 ± 2 overall. Dry bulk density averaged 0.12 ± 0.07 g/cm3 organic matter bulk density averaged 0.11 ± 0.05 g/cm3 and total carbon content in peat averaged 47 ± 6. In general large differences were found between Sphagnum and non Sphagnum peat types in terms of peat properties. Time weighted peat carbon accumulation rates averaged 23 ± 2 (standard error of mean) g C/m2/yr during the Holocene on the basis of 151 peat cores from 127 sites with the highest rates of carbon accumulation (25–28 g C/m2/yr) recorded during the early Holocene when the climate was warmer than the present. Furthermore we estimate the northern peatland carbon and nitrogen pools at 436 and 10 gigatons respectively. The database is publicly available at https://peatlands.lehigh.edu.

Chemical oxidation with acidified potassium dichromate is one of the more commonly used of a range of available methods for the quantification of black carbon (BC) in soils and sediments. There are potential uncertainties with this method however, with indications that not all non-BC material is susceptible to oxidation. An emerging approach to BC quantification is hydropyrolysis (hypy), in which pyrolysis assisted by high hydrogen pressure facilitates the reductive removal of labile organic matter, so isolating a highly stable portion of the BC continuum that is predominantly composed of >7 ring aromatic domains. Here, results from the hypy of the BC fraction isolated by dichromate oxidation (BC dox ) from a BC-rich soil are presented, which demonstrated that 88% of the total carbon initially defined as BC was stable under hypy conditions (defined as BC hypy ). More notably, hypy allowed the non-BC hypy fraction to be characterised. In addition to a number of PAHs, the non-BC hypy fraction was also found to contain a significant abundance of n -alkanes, with a marked predominance of even-numbered homologues. These compounds are probably derived from lipids, hydrogenated during hypy, which survived dichromate oxidation due to their hydrophobic nature. Hypy of the dichromate oxidation residue from a sample of Green River shale, known to contain no BC of pyrogenic origin revealed that the significant apparent BC dox content (BC/OC = 5.7%) was also largely due to the presence of n -alkanes within the oxidation residues. The distribution of these compounds, biased towards longer chain homologues with no significant even/odd preference, indicated that they were largely derived from long n -alkyl chains within this highly aliphatic matrix. Hypy therefore provides compelling direct evidence for the incomplete removal of non-BC material by dichromate oxidation from both a BC-rich soil and a BC-free oil shale, with the molecular characterisation of the non-BC hypy fraction allowing the potential sources of this material to be deduced.

Peat records enable the reconstruction of changes in the global biogeochemical mineral dust cycle and the detection of variations in atmospheric circulation patterns during the Holocene. They can therefore provide a key tool for understanding the relationship between the geochemical dust cycle and past climate change. Here, we present the first detailed study of the inorganic geochemistry of a peat core collected at an altitude of 3500 m from the Hongyuan peatland, on the eastern Qinghai-Tibetan Plateau, and test its potential as an archive of atmospheric dust deposition. We find that the low accumulation rates of the peat and the presence of the extensive dust sources of northern China in the vicinity of the study site lead to approximately five times higher concentrations of mineral matter compared to temperate ombrotrophic peats. A detailed geochemical assessment of the core and surface samples from local and non-local dust sources, as well as of the hydrology and hydrochemistry of the surrounding waters, suggests that external and internal post-depositional processes have not affected the record of lithogenic elements, including the rare earth elements (REE), Sc, Y and Th. Changes in Ti-normalized major element profiles, La/Yb, Y/Tb and the Eu anomaly identify seven major shifts among the dominant dust sources and therefore potential changes in atmospheric circulation patterns. Bivariate plots using the REE-based tracers La/Yb, Y/Tb, La/Th, Y/Er, Sc/La, Th/Sc and Th/ΣREE suggest that the Taklamakan desert and the Chinese loess plateau in northern China were the dominant non-local dust sources to the peat. Local dust input dominated throughout the early Holocene until 4.9 kyr BP. Increased dust input from the non-local sources thereafter suggests an enhanced influence of winds associated with the East Asian winter monsoon and the Westerly jet throughout most of the late Holocene. Sharp increases in non-local dust fluxes between 3.1–2.7 and between 1.3–0.9 kyr BP suggest a particular strengthening of these wind systems during these times, in agreement with the organic characteristics of the core. Our results show that the Hongyuan peat is a reliable archive to study dust deposition in central Asia and allows the identification of changes in atmospheric circulation patterns and in the larger climatic arrangements of the monsoon system in this region during the Holocene.

article i nfo During the Permian, peatland, as represented in extensive coal deposits, was a major component of the global carbon cycle. Carbon storage in peatland is a balance between decay and net primary production (NPP), which in turn are sensitive to variations in the concentration of atmospheric CO2 and O2. To evaluate peatland carbon storage and NPP during the Lopingian, a period thought to be characterised by higher atmospheric O2 and CO2 than modern levels, spectral analyses of geophysical data from a 15.1 m thick Lopingian (Upper Permian) coal in southwestern China were conducted to define the time frame of temporal carbon accumulation in tropical peatland. The result shows that the mineral matter content (ash yield) of the coal was possibly influenced by 123 ka (eccentricity), 35.6 ka (obliquity) and 21.2 ka (precession) Milankovitch periodicities. Using this timeframe and an understanding of carbon loss during coalification, the Lopingian tropical peatland carbon accumulation rate is calculated to be 61.1-73.0 g C/m 2 /yr which is expected to correspond to a NPP of 611- 1460 g C/m 2 /yr respectively. A comparison between the predicted Pennsylvanian (Late Carboniferous) NPP and modern values indicates that the Permian NPP calculated is consistent with geochemical and paleobotanical models, supporting a proposal that productivity was mainly controlled by temporal atmospheric O2 and CO2 levels.

Charcoal is the result of natural and anthropogenic burning events, when biomass is exposed to elevated temperatures under conditions of restricted oxygen. This process produces a range of materials, collectively known as pyrogenic carbon, the most inert fraction of which is known as black carbon (BC). BC degrades extremely slowly and is resistant to diagenetic alteration involving the addition of exogenous carbon, making it a useful target substance for radiocarbon dating particularly of more ancient samples, where contamination issues are critical. We present results of tests using a new method for the quantification and isolation of BC, known as hydropyrolysis (hypy). Results show controlled reductive removal of non-BC organic components in charcoal samples, including lignocellulosic and humic material. The process is reproducible and rapid, making hypy a promising new approach not only for isolation of purified BC for 14C measurement but also in quantification of different labile and resistant sample C fractions.

International audience; Peatland of the eastern Qinghai­Tibetan Plateau lies at the convergence of the East Asian and Indian monsoon systems in eastern Asia. To understand the evolution of this peatland and its potential to provide new insights into the Holocene evolution of the East Asian monsoon a 6 m peat core was collected from the undisturbed central part of a peat deposit near Hongyuan. The age-depth profile was determined using 16 14C-AMS age dates, the peat analysed for a range of environmental variables including carbon, nitrogen and hydrogen concentration, bulk density, d13C and the associated spring water analysed for hydrogen and oxygen isotopes. The age-depth profile of the recovered peat sequence covers the period from 9.6 to 0.3 kyr BP and is linear indicating that the conditions governing productivity and decay varied little over the Holocene. Using changes in carbon density, organic carbon content and its d13C, cold dry periods of permafrost characterised by low density and impeded surface drainage were identified. The low d18O and dD values of the spring water emanating around the peat deposit, down to -13.8 and -102 (VSMOW), respectively, with an inverse relationship between electrical conductivity and isotopic composition indicate precipitation under colder and drier conditions relative to the present day. In view of the current annual mean air temperature of 1 °C this suggests conditions in the past have been conducive to permafrost. Inferred periods of permafrost correspond to independently recognised cold periods in other Holocene records from across China at 8.6, 8.2­7.8, 5.6­4.2, 3.1 and 1.8­1.5 kyr BP. The transition to a cold dry climate appears to be more rapid than the subsequent recovery and cold dry periods at Hongyuan are of longer duration than equivalent cold dry periods over central and eastern China. Light­dark banding peat on a scale of 15­30 years from 9.6 to 5.5 kyr BP may indicate a strong influence of decadal oscillations possibly the Pacific Decadal Oscillation and a potential link between near simultaneous climatic changes in the northwest Pacific, ENSO, movement of the Intertropical Convergence Zone and the East Asian Monsoon.

Much research has suggested that venture capital (VC) investors can contribute post-investment to the success of new ventures in ways other than financing, but the specifics of such post-investment non-financial value-added (NFVA) are still not well understood. We systematically review, organize and evaluate the empirical research on VC NFVA, and compile together results that were previously scattered across many papers. In the 20 salient studies of VC NFVA published between 1986 and 2005, we observe little consensus regarding the definition and measurement of value-adding inputs and value-added outcomes, and little consensus regarding which of the VCs' value-adding inputs are most important. We further observe that NFVA studies have employed either qualitative methods or quantitative measures of retrospective perceptions. To guide future research, we propose a provisional model of VC exit success and a provisional eight-category typology of value-adding inputs that accommodates the findings in the litera...

Our understanding of the hydrodynamic response of peatland to climate change is restricted to the Holocene, which confines our knowledge of the fundamental controls on this important carbon reservoir to recent sedimentary successions. To understand the interaction of peatland hydrodynamics, climate and the carbon cycle on longer time scales, a 95.4 m record from lower Miocene lignite from the Gippsland Basin, Australia is considered. δ 13 C and colour records for the lignite were created by analysing samples every 0.1 m. Solid-state 13 C NMR results indicate that lignite colour is related to the relative abundance of aliphatic carbon. The lack of a direct correlation between colour and δ 13 C demonstrates that the δ 13 C signal has not been significantly influenced by the diagenetic processes that produce the colour. An offset correlation occurs between δ 13 C and colour with the degree of offset decreasing from 4.5 m at the base to about 0 m at the top. This offset is considered to represent a zone of surface influence that extends up to 20 m below the peat surface. Using numerical modelling we demonstrate that this zone of surface influence and its gradual decline in thickness could arise as a consequence of enhanced fluid flow in regions of high tensile stress within the unconfined peat body. The removal of lignin and its derivatives from the zone of surface influence will be favoured by cooler drier periods, with lower sea level and high hydraulic gradients across the peatland. Therefore in the early Miocene this peatland acted as a carbon source during global cooling.

Hydropyrolysis (hypy) as a fast means for preparing lignin concentrates for stable carbon isotope analysis was evaluated by performing hypy at different temperatures (200–500 °C) on Klason lignin concentrates, cellulose, and wood samples followed by bulk stable carbon isotope analysis of the solid residues. The δ 13 C values of cellulose, Klason lignin and their hypy residues revealed that hypy does not produce isotopic fractionation throughout the temperature range explored. The δ 13 C of hypy residues from cellulose-Klason lignin physical mixtures obtained at 500 °C were in the value range of the corresponding Klason lignin indicating that cellulose decomposed completely and that no major structural rearrangements, which could lead to carbon cross-linking between these two moieties are produced by hypy. The hypy residues obtained from wood samples at 500 °C were consistently depleted in 13 C by 0.8‰ and enriched by 1.6‰ relative to the original wood and Klason lignin, respectively. This finding results from polysaccharide derivatives remaining in the wood residue, with a percentage of polysaccharide derived carbon 1.9 and 3.7 times higher than expected at 300 and 350 °C, respectively. It is concluded that the results presented here provide an indicator of the extent of cross-linking between lignin and polysaccharides (hemicellulose) in the native wood forming lignin–carbohydrate complexes.

The use of hydropyrolysis (hypy) is described as a potentially rapid procedure for obtaining lignin-enriched residues from wood for either simply estimating lignin content or for performing stable isotope ratio measurements. Hypy was carried out on samples of oak wood and, as reference materials, Klason lignin and pure cellulose over the temperature range of 200–500 °C. The composition of the residues were assessed by solid-state 13C NMR. At 300 and 350 °C, the extents of conversion achieved for cellulose was 88 and 95% respectively, indicating that highly lignin-enriched residues should be obtained for wood samples. This was confirmed by solid-state 13C NMR which also indicated that any remaining cellulose had aromatised to a significant extent. In addition, hypy caused quite extensive demethylation of methoxyl functionalities and cleavage of the characteristic β-O-4 ether lignin linkage. Finally, correcting the 300 and 350 °C hypy residues for residual cellulose gave estimates of the lignin content for oak wood in close agreement with those obtained by the Klason method and by solid-state 13C NMR. At 350 °C, the residual cellulose accounts for ca. 30% of the lignin concentrate obtained from hypy.

The application of sequential extraction procedures to determine metal speciation in sediments is fraught with uncertainty regarding what is actually dissolving or re-precipitating at each stage. In order to choose an appropriate scheme for the investigation of contaminated anaerobic mud two different sequential extraction procedures (Kersten and Forstner, 1986; Quevauviller, 1998) were investigated using a Cryogenic SEM (CryoSEM) technique coupled with energy dispersive X-ray analysis (EDXA). This enabled assessment of the degree of reagent selectivity and any re-precipitation associated with the respective methods. Analysis of the non-leached sediment revealed the most abundant authigenic minerals in order of decreasing abundance to be Fe2+-phosphate vivianite (Fe3(PO4)2·8H2O), mixed Fe, Zn, Cu sulphides, pyrite and calcite. After each stage of the sequential extraction the sediment residue was examined using CryoSEM. After extraction of the exchangeable fraction no obvious evidence of mineral dissolution was observed. Calcite was not completely dissolved during the carbonate extraction stage of either procedure. Vivianite began to dissolve in the carbonate extraction stage of both procedures and was completely dissolved by oxide extraction stage of both procedures. The sediment leached by acidified ammonium oxalate, contained abundant Fe oxalate crystals, suggesting that a large proportion of the Fe released from the vivianite has been re-precipitated. The Fe oxalate was then dissolved with the subsequent sulphide fraction. The technique used to extract the sulphide and organic fraction is the same in both schemes and no sulphide or metal rich organic matter was found in either residue.

Poorly crystalline carbonaceous matter was observed in chlorite to sillimanite grade metasediments from the Trois Seigneurs Massif, in contrast to other studies of carbon crystallinity which observed well crystallised graphite under upper greenschist facies conditions. Using transmission electron microscopy four types of carbon particle were identified; globular carbon, composite flakes, homogeneous flakes and crystalline graphite. Globular carbon and composite flakes are poorly crystalline microporous carbon. Homogeneous flakes decompose in the electron beam and are probably composed of heavy volatile hydrocarbons. Graphite is confined to samples from retrograde shear zones and often occurs with globular carbon. The lack of graphitisation in metasediments is probably a consequence of the microporous structure of the carbonaceous matter combined with low fO2. The preservation of carbonaceous matter in the Trois Seigneurs metasediments is not compatible with the metasediments having been externally buffered by a high XH2O fluid syn-metamorphism. An alternative hypothesis of internal buffering is preferred to explain the carbonaceous matter in the Trois Seigneurs metasediments.

An optical system architecture intended to provide subscriber access for future network sevices must also support existing services at a cost equivalent to copper. An integrated optical-fiber system which meets this criterion and provides both CATV and telephone service has been designed under contract to the Deutsche Bundespost and is planned for pilot installation early in 1990 in Koln, Federal Republic of Germany. A bus network was chosen for implementation of the trial system because of the advantages it provides over a point-to-point star network. Economies result from using much less fiber per subscriber, and from the sharing of optical transmitter and receiver costs among many subscribers. The telephony portion of the system initially provides existing telephone service based on digital transmission technology yet is configured to support the development of new services. The CATV portion of the network is designed to be functionally equivalent to the coaxial system now being deployed, but offers advantages in reliability and future expansion possibilities. The implementation of a system using a bus architecture to provide network access for telephone and broadband CATV services over optical fiber cables is described.