Vlahakis C.,European Southern Observatory |
Vlahakis C.,University of Chile |
Vlahakis C.,Leiden University |
Van Der Werf P.,Leiden University |
And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2013
We present the first complete CO J = 3-2 map of the nearby grand-design spiral galaxy M51 (NGC 5194), at a spatial resolution of ∼600 pc, obtained with the HARP-B instrument on the James Clerk Maxwell Telescope. The map covers the entire optical galaxy disc and out to the companion NGC 5195, with CO J = 3-2 emission detected over an area of ∼9 arcmin × 6 arcmin (∼21 × 14kpc). We describe the CO J = 3-2 integrated intensity map and combine our results with maps of CO J = 2-1, CO J = 1-0 and other data from the literature to investigate the variation of the molecular gas, atomic gas and polycyclic aromatic hydrocarbon (PAH) properties of M51 as a function of distance along the spiral structure on sub-kiloparsec scales. We find that for the CO J = 3-2 and CO J = 2-1 transitions, there is a clear difference between the variation of arm and interarm emission with galactocentric radius, with the interarm emission relatively constant with radius and the contrast between arm and interarm emission decreasing with radius. For the CO J=1-0 line and Hi emission, the variation with radius shows a similar trend for the arm and interarm regions, and the arm-interarm contrast appears relatively constant with radius. We investigate the variation of CO line ratios (J = 3-2/2-1, J = 2-1/1-0 and J = 3-2/1-0) as a function of distance along the spiral structure. Line ratios are consistent with the range of typical values for other nearby galaxies in the literature. The highest CO J = 3-2/J = 2-1 line ratios are found in the central ∼1 kiloparsec and in the spiral arms and the lowest line ratios in the interarm regions. We find no clear evidence of a trend with radius for the spiral arms, but for the interarm regions there appears to be a trend for all CO line ratios to increase with radius. We find a strong relationship between the ratio of CO J = 3-2 intensity to stellar-continuum-subtracted 8 μm PAH surface brightness and the CO J = 3-2 intensity that appears to vary with radius. © 2013 The Authors. Source
Bendo G.J.,Imperial College London |
Wilson C.D.,McMaster University |
Warren B.E.,McMaster University |
Warren B.E.,University of Western Australia |
And 25 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2010
We used Spitzer Space Telescope 3.6, 8.0, 70 and 160 μm data, James Clerk Maxwell Telescope HARP-B CO J = (3-2) data, National Radio Astronomy Observatory 12 m telescope CO J= (1-0) data and Very Large Array H i data to investigate the relations among polycyclic aromatic hydrocarbons (PAHs), cold (∼20 K) dust, molecular gas and atomic gas within NGC 2403, an SABcd galaxy at a distance of 3.13 Mpc. The dust surface density is mainly a function of the total (atomic and molecular) gas surface density and galactocentric radius. The gas-to-dust ratio monotonically increases with radius, arying from ∼100 in the nucleus to ∼400 at 5.5 kpc. The slope of the gas-to-dust ratio is close to that of the oxygen abundance, suggesting that metallicity strongly affects the gas-to-dust ratio within this galaxy. The exponential scale length of the radial profile for the CO J = (3-2) emission is statistically identical to the scale length for the stellar continuum-subtracted 8 μm (PAH 8 μm) emission. However, CO J equals; (3-2) and PAH 8 μm surface brightnesses appear uncorrelated when examining sub-kpc-sized regions. © 2010 The Authors. Journal compilation © 2010 RAS. Source
Over fifty per cent of our biomass use for energy still comes from traditional biomass, such as firewood, charcoal, animal manure and agricultural residues. On the other hand poses the use of biomass a threat to food security. Increasing food production and shifting towards more and better use of biofuels are challenges that can and should be handled simultaneously. One of the approaches could be increasing land use efficiency by a more effective biomass use. Increasing biomass use can be done by allocating biomass fractions to optimise their values. For instance, allocating more harvest to food, optimising nutrient recycling or reducing losses. In Indonesia, the oil production from the rubber tree, oil palm or Jatropha seeds results in solid waste streams that contain protein. These protein fractions can be utilised for applications to feed stock. Rubber seed was selected by the researchers for its protein and oil contents, as well as its availability in the study area. Rubber seed kernel contains 17 per cent protein. After oil pressing, alkaline extraction and isoelectric precipitation, the researchers managed to increase the percentage of protein to 48. Utilisation of protein fractions from rubber seeds presents opportunities to increase revenue from rubber plantation. The most potential application for the farmers is using the rubber seed protein concentrate for animal feed. The experimental work of Widyarani comprised optimising protein extraction, protein hydrolysis, and separation of free amino acids from hydrolysates. The whole rubber tree chain, including latex and wood production, was analysed for additional options for protein recovery. Next to rubber seeds, leaves from rubber trees appeared to be a promising protein source. Two restrictions to the use of rubber seed proteins for amino acid production apply though. The prize of enzymes and separate amino acid from the mixture. Hydrolysis using protease could achieve high degree of hydrolysis, resulted in hydrolysates that were rich in short peptides and free amino acids. A protease combination that has high selectivity towards hydrophobic amino acids was selected. Ethanol precipitation was used for separation of the hydrolysate, and separation between hydrophobic and hydrophilic amino acids was shown as an alternative tool in amino acids purification process. Widyarani's research took place within the project 'Breakthroughs in biofuels: Mobile technology for biodiesel production from Indonesian resources' of Hero Heeres (RUG). This project is part of the NWO-WOTRO Science for global development research programme 'Agriculture beyond food'. The promotor of Widyarani's PhD research – resulting in her thesis 'Biorefinery of Proteins from Rubber Plantation Residues' - was Johan Sanders (WUR). The Agriculture Beyond Food research programme stimulates long term cooperation between research groups from Indonesia and Netherlands on the potential benefits of biomass and the social, economic and policy impact. Agriculture Beyond Food is divided into three clusters: the introduction of Jatropha as an alternative biofuel, mobile technologies for biodiesel production, and the effects of an increasing production of palm oil. Agriculture Beyond Food started in 2008, and a total of 2.5 million euros is available for the research. The programme is financed by the Netherlands Organisation for Scientific Research (NWO-WOTRO), the Royal Netherlands Academy of Arts and Sciences (KNAW), and is carried out in collaboration with the Indonesian Ministry of Research, Technology and Higher Education (formerly RISTEK).
Emissions stall Humanity’s greenhouse-gas output increased by just 0.5% in 2014, despite significant global economic growth, according to figures released on 25 November. Carbon emissions rose by 3–4% per year in the first decade of the twenty-first century, but that growth has slowed dramatically over the past 3 years, report the Netherlands Environmental Assessment Agency and the European Commission’s Joint Research Centre. The biggest factor is China, where slower economic growth and a shift towards cleaner energy sources and less energy-intensive manufacturing have reduced the energy intensity of the economy. See go.nature.com/kphlae for more. Deforestation rises The rate of legal deforestation in the Amazon rainforest has risen over the past year, Brazilian environment minister Izabella Teixeira announced on 26 November. Satellite images show that 5,831 square kilometres of forest were lost to activities such as livestock farming and agriculture in the year up to July 2015, a 16% increase on the previous year. The increases were largest in the states of Rondônia, Mato Grosso and Amazonas. Of these, Mato Grosso had the biggest area of forest loss, at 1,508 square kilometres. Efforts by the Brazilian federal government have generally been bringing down rates of deforestation, and the current rate is around one-fifth of that in 2004. Blue Origin gets to space and back Commercial spaceflight company Blue Origin — the brainchild of Jeff Bezos, head of online retail giant Amazon — completed a test of its reusable rocket on 23 November. The autonomous vehicle was successfully landed after it propelled a capsule to a height of more than 100 kilometres, which is classed as being in space. The flight comes just seven months after one of the company’s rockets was destroyed during a similar test. Blue Origin has not yet completed a crewed flight; the capsule is designed to carry up to six passengers into space. Anthrax vaccine An anthrax vaccine has become the first to be approved by the US Food and Drug Administration (FDA) under the ‘Animal Rule’, which allows approval on the basis of animal tests when studies in humans are not ethical or possible. The FDA announced on 23 November that the vaccine, called BioThrax, can be used after exposure to Bacillus anthracis, the bacterium that causes anthrax. BioThrax was initially approved in 1970 to prevent anthrax before exposure to the bacterium. The vaccine is made by Emergent BioDefense Operations Lansing in Michigan. Retraction data A searchable database should soon allow systematic identification of retracted publications. Posts and article identifiers from the blog Retraction Watch will be incorporated into a web application maintained by Center for Open Science in Charlottesville, Virginia, that already tracks research activities such as posting preprints or depositing data sets. The resource will initially have about 5,000 entries, and was announced by both organizations on 24 November. LHC heavy metal After spending five months colliding protons following a major upgrade this year, the Large Hadron Collider (LHC) near Geneva, Switzerland, began a one-month run of experiments with heavy ions on 25 November. All main detectors at the accelerator — including ALICE, which was designed for this purpose — are now studying the state of matter known as quark–gluon plasma, which can arise when two nuclei of lead-208 collide. In these collisions, the nuclei carry a record-breaking energy of more than 1 petaelectronvolt. Energy partnership A group of 28 investors from 10 countries has launched a multibillion-dollar clean-energy research partnership. The Breakthrough Energy Coalition, spearheaded by Microsoft founder Bill Gates, and including Virgin founder Richard Branson and Amazon boss Jeff Bezos, was announced on 30 November, on the opening day of the international climate-change negotiations in Paris. The private partnership aims to support early-stage research into low-carbon technologies for future energy supply. It will complement energy-research efforts announced by US President Barack Obama and French President François Hollande on the same day, dubbed ‘Mission Innovation’. See go.nature.com/wzigmx for more. Maurice Strong Maurice Strong, the founding head of the United Nations Environment Programme (UNEP) and a leading figure in climate-change politics, has died aged 86. He was a major figure in organizing the 1992 Rio Earth Summit and creating the UN Framework Convention on Climate Change. Strong is regarded as one of the most important people in the history of the environmental and sustainability movements. In a statement released by UNEP on 28 November, Achim Steiner, the current head of the agency, called him a visionary and a pioneer of global sustainable development. Rhino-horn ban A South African court has lifted a ban on the domestic trade in rhino horn (pictured) after two game farmers claimed that it infringed their right to trade in a renewable substance. On 26 November, the judge ruled that the ban, introduced in 2009, had not undergone proper public consultation. He added that since 2008 the number of South African rhinos poached for their horns has increased from less than 100 per year to around 1,200. Conservation group Save the Rhino asked how a national ban could fuel poaching, which mainly serves overseas markets, given that the international trade is illegal. The South African government is to appeal the ruling; the law will stay in place until the appeal has been heard. Carbon plan canned On 25 November, the UK government scrapped a £1-billion (US$1.5-billion) competition to build a demonstration carbon capture and storage plant. Funding for the project — intended to demonstrate that carbon dioxide can be filtered out of power-plant exhaust gases on a commercial scale — has been on the table since 2012, but was removed from government plans in the latest five-year spending review. Open-access policy The Netherlands Organisation for Scientific Research (NWO) is tightening its open-access policy to demand that research results become universally available as soon as authors publish them. NWO-funded researchers were previously obliged either to publish in an open-access journal or to submit a version of their work to a public database ‘as soon as possible’ after publishing in a pay-to-read journal. From 1 December, new grant conditions require Dutch researchers to make work immediately accessible. To avoid conflicting with journals that enforce embargo periods, such as Nature, researchers can submit pre-peer-review versions to a database. Animal clones A huge animal-cloning centre in Tianjin, China, will open early in 2016. Launched with 200 million yuan (US$31.3 million) from Sinica, a subsidiary of BoyaLife in Wuxi, the Tianjin International Joint Academy of Biomedicine, Peking University in Beijing and Sooam Biotech in Seoul, the centre will clone cattle, dogs and racehorses. BoyaLife says that the aim is to produce one million cloned cow embryos annually to help Chinese farmers to meet demand for beef. Italian expo The Italian government enacted a decree on 25 November that allocates €80 million (US$85 million) to launch a major research centre to focus on big-data exploitation in health and nutrition, as well as nanotechnologies. Called Human Technopole, the centre will take over part of the site used for the 2015 international exhibition called Milan Expo. It will continue the theme of the exhibition — ‘feeding the planet, energy for life’. Human Technopole will be led by the Genoa-based Italian Institute of Technology and will eventually employ more than 1,000 researchers. European politicians often allow more fish to be taken from the seas than is recommended by scientists. Yet this excess varies by country, according to a study (G. Carpenter et al. Mar. Policy 64, 9–15; 2016). In 2001, the total catch permitted in the European Union averaged 33% more than that advised by the International Council for the Exploration of the Sea. In 2015, this fell to 7% above the advised level. EU politicians negotiate catch limits in secret, but more transparency is needed, say the authors. 3–4 December The first International Workshop on Metamaterials-by-design takes place in Paris. go.nature.com/hkzg9s 8–9 December The Royal Society of Medicine and the Nutrition Society in London jointly host a meeting that will look at the role of sleep in obesity and nutrition. go.nature.com/xigwne
Below the soil of a diverse grassland area you'll find a jungle of plant roots. It is also home to a wide variety of bacteria and fungi, of which some are pathogenic and looking for a host in the tangle of roots. It appears that this is much more difficult when there is a larger diversity of plants as the host plant is more able to hide among the varied crowd. Greater plant diversity therefore results in fewer diseased plants and more productivity. Personal professor in Plant Ecology Liesje Mommer will be using a VIDI subsidy to look into the mechanisms behind this phenomenon. "Quite a lot is known about the interaction between certain fungi and plant varieties – especially agricultural crops, and particularly within the molecular framework," says Mommer. "But this does not apply to the relations between multiple fungi and plant varieties, or in natural ecosystems. This is a very complex issue." It has been known for some time that a broader diversity of plants in natural grassland increases productivity; almost as if the plants are cheering each other on. The theory was that every variety occupies its own niche, with more varieties meaning enhanced productivity. In her VENI research, Mommer showed that it is much more complicated than that. She used molecular techniques to quantify the various types of roots (which visually all look alike). This showed that the varieties mainly occupy the top layer of the soil, which allowed her to conclude that niches were not applicable. Supported by the VIDI subsidy from the Netherlands Organisation for Scientific Research (NWO) she is now following up on the previous research with two research assistants. "We are examining plant-soil feedback: the plant influences its own micro-organisms on the root – albeit positively or negatively. In a monoculture the pathogens accumulate which affects the productivity. In a diverse mixture there are fewer pathogens and we will now be studying why that is." The daisy, for instance, is susceptible to the fungus Paraphoma chrysanthemicola. More daisies in the grassland therefore means more of that type of fungus. However, it appears that individual flowers are better at hiding between the roots of other varieties. "A new aspect is whether the daisy is better at hiding between grass varieties or between the roots of plants that are more closely related. From the perspective of the fungus we could ask ourselves: is it the density of the roots that makes it harder for the fungus to find the host plant? Or does the fungus lose its way because various plants secrete different sugars and aromatics?" Mommer and her team are using pot tests to learn the rules of the game; then she will study whether the same rules apply in the field. The research results may be useful for nature management as well as agriculture. "If you mix the cultivation of varieties, also known as intercropping, the average pathogen reduction is 40 per cent. Nobody knows exactly why. Maybe planting different plants strategically in between the crops could also have a fungus-reducing effect." Explore further: Knowledge of fungi helps to map risks of genetically modified crops