Nitrogen as a threat to the European greenhouse balance

Reactive nitrogen (N_r) is of fundamental importance in biological and chemical processes in the atmosphere-biosphere system, altering the Earth's climate balance in many ways. These include the direct and indirect emissions of nitrous oxide (N2O), atmospheric N_r deposition and tropospheric ozone formation (O3), both of which alter the biospheric CO2 sink, N_r supply effects on CH4 emissions, and the formation of secondary atmospheric aerosols resulting from the emissions of nitrogen oxides (NOx) and ammonia (NH3). Human production and release of N_r into the environment is thus expected to have been an important driver of European greenhouse balance. Until now, no assessment has been made of how much of an effect European N_r emissions are having on net warming or cooling

Modelling and mapping UK emissions of ammonia, methane and nitrous oxide from agriculture, nature, waste disposal and other miscellaneous sources for 2013

A contribution to the UK National Atmospheric Emission Inventory and Greenhouse Gas Inventory

Stem Cell Organoids in Primary Cultures of Human Non-Malignant and Malignant Colon

YesA sub-population of cells named cancer stem cells (CSCs) that initiate and promote tumour growth have been demonstrated to exist in several malignancies including colon carcinoma. The objective of our pilot study was to isolate CD133+CD26+CD44+ CSCs from patient colon tumours, culture spheres or organoids and observe their proliferation in primary cultures. Parallel cultures of non-cancer controls from colon normal lining and nonadenomatous polyps were set up. Magnetic activated cell sorting was used to isolate CD133+CD26+CD44+ cell populations followed by primary cell culturing under stem cell culture conditions. Number, cells/organoid and daughter generations of organoids were calculated using phase contrast microscope. Trypan blue exclusion method was used to test the viability of the cells. Both colon tumour and colon non-adenomatous polyp formed floating organoids in suspension; however non-adenomatous polyp cultures did not show self-renewal properties for more than 1 passage. Normal colon singlecell suspension did not create organoids. Metastatic colon tumours rapidly produce cancer cell organoids in less than 24 hours in larger numbers compared to non-metastatic colon tumours (1-3 weeks). Metastatic colon tumour organoids have the ability for proliferation for upto five daughter generations in primary culture compared to three generations for those grown from non-metastatic tumours. This in vitro CSC organoid model will help study colon cancer biology, in particular providing a valuable source of primary cell-derived tissue for studying personalized molecular profiling using ‘omics strategies to direct therapeutic intervention

Membrane Spin Up in a Normal Gravity Field: Experiments and Simulations

Finite element simulations and experimental observations of the spin up in vacuum of a thin membrane loaded by gravity are presented. The numerical techniques take into account the run time of each simulation and energy convergence; it is shown that accurate results can be obtained quite quickly in a rotating reference frame, and that including stiffness-proportional material damping helps convergence of the integration. It is also found that a very fine finite element mesh around the hub of the membrane is required to obtain consistent results. The experimental setup allows spinning of the membrane in a vacuum box; a measurement technique that uses stereo Digital Image Correlation is presented. A comparison between experiments and simulations using characteristic parameters of the shape of a membrane, i.e. the number of rotational symmetric waves, the average deflection, and the elastic bending strain energy of the membrane, shows good agreement between experiments and simulations

Dynamic assembly of Hda and the sliding clamp in the regulation of replication licensing

Regulatory inactivation of DnaA (RIDA) is one of the major regulatory mechanisms of prokaryotic replication licensing. In RIDA, the Hda-sliding clamp complex loaded onto DNA directly interacts with adenosine triphosphate (ATP)-bound DnaA and stimulates the hydrolysis of ATP to inactivate DnaA. A prediction is that the activity of Hda is tightly controlled to ensure that replication initiation occurs only once per cell cycle. Here, we determined the crystal structure of the Hda-�� clamp complex. This complex contains two pairs of Hda dimers sandwiched between two �� clamp rings to form an octamer that is stabilized by three discrete interfaces. Two separate surfaces of Hda make contact with the �� clamp, which is essential for Hda function in RIDA. The third interface between Hda monomers occludes the active site arginine finger, blocking its access to DnaA. Taken together, our structural and mutational analyses of the Hda-�� clamp complex indicate that the interaction of the �� clamp with Hda controls the ability of Hda to interact with DnaA. In the octameric Hda-�� clamp complex, the inability of Hda to interact with DnaA is a novel mechanism that may regulate Hda function. ? The Author(s) 2017.113Ysciescopu

Drivers of long-term variability in CO2 net ecosystem exchange in a temperate peatland

Land–atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits marked seasonal and inter-annual variability, which subsequently affects the carbon (C) sink strength of catchments across multiple temporal scales. Long-term studies are needed to fully capture the natural variability and therefore identify the key hydrometeorological drivers in the net ecosystem exchange (NEE) of CO2. Since 2002, NEE has been measured continuously by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in central Scotland. Hence this is one of the longest peatland NEE studies to date. For 11 years, the site was a consistent, yet variable, atmospheric CO2 sink ranging from −5.2 to −135.9 g CO2-C m−2 yr−1 (mean of −64.1 ± 33.6 g CO2-C m−2 yr−1). Inter-annual variability in NEE was positively correlated to the length of the growing season. Mean winter air temperature explained 87% of the inter-annual variability in the sink strength of the following summer, indicating an effect of winter climate on local phenology. Ecosystem respiration (Reco) was enhanced by drought, which also depressed gross primary productivity (GPP). The CO2 uptake rate during the growing season was comparable to three other sites with long-term NEE records; however, the emission rate during the dormant season was significantly higher. To summarise, the NEE of the peatland studied is modulated by two dominant factors: - phenology of the plant community, which is driven by winter air temperature and impacts photosynthetic potential and net CO2 uptake during the growing season (colder winters are linked to lower summer NEE), - water table level, which enhanced soil respiration and decreased GPP during dry spells. Although summer dry spells were sporadic during the study period, the positive effects of the current climatic trend towards milder winters on the site's CO2 sink strength could be offset by changes in precipitation patterns especially during the growing season

Valence-quark distributions in the pion

We calculate the pion's valence-quark momentum-fraction probability distribution using a Dyson-Schwinger equation model. Valence-quarks with an active mass of 0.30 GeV carry 71% of the pion's momentum at a resolving scale q_0=0.54 GeV = 1/(0.37 fm). The shape of the calculated distribution is characteristic of a strongly bound system and, evolved from q_0 to q=2 GeV, it yields first, second and third moments in agreement with lattice and phenomenological estimates, and valence-quarks carrying 49% of the pion's momentum. However, pointwise there is a discrepancy between our calculated distribution and that hitherto inferred from parametrisations of extant pion-nucleon Drell-Yan data.Comment: 8 pages, 3 figures, REVTEX, aps.sty, epsfig.sty, minor corrections, version to appear in PR

Ammonia Reductions and Costs Implied By the Three Ambition Levels Proposed in the Draft Annex IX to the Gothenburg Protocol

The Convention on Long-range Transboundary Air Pollution has started negotiations on the revision of its Gothenburg multi-pollutant/multi-effect protocol. Among other topics, emissions of ammonia have been subject of specific scrutiny. To inform negotiations, the Task Force on Reactive Nitrogen (TFRN) has compiled a list of potential ammonia emission control measures that could form an annex to the protocol. This "Draft Annex IX" defines three ambition levels, ranging from the most stringent level "A" to the least ambitious level "C". This report presents estimates of the ammonia emission reductions and costs of the measures that are included in the Draft Annex IX prepared for the revision of the Gothenburg Protocol. The estimates for the three different ambition levels have been derived with the GAINS model, and it is assumed that these measures are equally implemented for all countries, even if they are not cost-effective. The specific assumptions in translating the specifications provided in the Draft Annex IX into GAINS input data are described in this paper. Costs for implementing the ambition levels vary across countries. Taking into account recent information on ammonia emission control costs that has been compiled by the Task Force on Reactive Nitrogen it is found that overall costs of the proposed measures are generally low. Per unit of emissions abated, costs are typically only up to 1 Euro per kg NH3-N abated with a few outliers which, however, stay below 5 Euro per kg NH3-N abated. Total abatement costs are modest, for the most ambitious scenario A they amount to 8/1000 of 1% of the GDP in 2020. In relative terms (e.g., expressed as percentage of GDP) costs are higher in the non-EU countries than in the EU-27. It is found that the specific measures, if uniformly implemented in all countries, would be less cost-effective than the (country-specific) least-cost set of measures that are derived from the GAINS optimization, e.g., for the MID and LOW cases in CIAM 4/2011 report, where the model can choose from a wider set of options