ALBERT

Description: Nature Physics 11, 21 (2015). doi:10.1038/nphys3146 Authors: I. Lukyanchuk, V. M. Vinokur, A. Rydh, R. Xie, M. V. Milošević, U. Welp, M. Zach, Z. L. Xiao, G. W. Crabtree, S. J. Bending, F. M. Peeters & W. K. Kwok Depending on the Ginzburg–Landau parameter κ, superconductors can either be fully diamagnetic if nphys3146-m1gif2765816 (type I superconductors) or allow magnetic flux to penetrate through Abrikosov vortices if nphys3146-m2gif2695416 (type II superconductors; refs , ). At the Bogomolny critical point, nphys3146-m3gif3178916, a state that is infinitely degenerate with respect to vortex spatial configurations arises. Despite in-depth investigations of conventional type I and type II superconductors, a thorough understanding of the magnetic behaviour in the near-Bogomolny critical regime at κ  κc remains lacking. Here we report that in confined systems the critical regime expands over a finite interval of κ forming a critical superconducting state. We show that in this state, in a sample with dimensions comparable to the vortex core size, vortices merge into a multi-quanta droplet, which undergoes Rayleigh instability on increasing κ and decays by emitting single vortices. Superconducting vortices realize Nielsen–Olesen singular solutions of the Abelian Higgs model, which is pervasive in phenomena ranging from quantum electrodynamics to cosmology. Our study of the transient dynamics of Abrikosov–Nielsen–Olesen vortices in systems with boundaries promises access to non-trivial effects in quantum field theory by means of bench-top laboratory experiments.

Description: The city of Aksu, situated at the northern fringe of the Taklimakan Desert in northwest China, is exposed to severe periodic dust and sand storms. In 1986, local authorities decided to establish a peri-urban shelterbelt plantation, the so-called Kökyar Protection Forest, with the aim of reducing dust and sand storm impacts on Aksu City by the regulating ecosystem services provided by the plantation. It was realised as a patchwork of poplar shelterbelts and orchards. The total area of the plantation reached 3800 ha in 2005. The Kökyar Protection Forest is used as a case study to answer the following question: under which institutional frameworks and to which financial conditions can peri-urban shelterbelts be established and maintained? The endeavour of planting the shelterbelt was made possible by the annual mass mobilisation of Aksu citizens, based on the Chinese regulation of the "National Compulsory Afforestation Campaigns". Establishment costs amounted to ca. CNY 60 000 ha−1 (ca. USD 10 000 ha−1). Permanent maintenance of the plantation is facilitated by leasing orchard plots to private fruit farmers. From the perspective of the local economy, annual farming net benefits generated by Kökyar fruit farmers more than compensate for annual government grants for maintenance, resulting in an average overall monetary net benefit of at least CNY 10 500 ha−1 (ca. USD 1600 ha−1) in the long term. For a more complete understanding of Kökyar Protection Forest, future research should be directed towards quantifying the effect of its regulating ecosystem services and on investigating the negative downstream consequences of its water consumption.

Description: The city of Aksu, situated at the northern fringe of the Taklimakan Desert in the northwest of China, is exposed to periodic severe dust and sand storms. In 1986, local authorities decided to establish a peri-urban shelterbelt plantation, the so-called Kökyar Protection Forest. It was realised as a patchwork of poplar shelterbelts and orchards. The total area of the plantation reached 3800 ha in 2005. This endeavour was made possible by the annual mass mobilisation of Aksu citizens, based on the Chinese regulation of the "National Compulsory Afforestation Campaigns". Establishment costs amounted to ca. CNY 60 000 ha−1 (ca. USD 10 000 ha−1). The regulating ecosystem services provided by Kökyar Protection Forest clearly reduce dust and sand storm impacts on Aksu City. Permanent maintenance of the plantation is facilitated by leasing orchard plots to private fruit farmers. This system ensures forest tending, reduces government expenses, and provides incomes to farmers. From the perspective of the local economy, annual farming net benefits generated by Kökyar fruit farmers more than compensate annual government grants for maintenance, resulting in an overall monetary net benefit of at least CNY 10 500 ha−1 (ca. USD 1600 ha−1) on the long-term average. The intended regulating ecosystem services can thus be provided to the citizens of Aksu without payments for ecosystem services or other financial burdens. For a more complete understanding of Kökyar Protection Forest, future research should be directed towards quantifying the effect of its regulating ecosystem services, and on investigating the negative downstream consequences of its water consumption.

Description: The Tarim River basin, located in Xinjiang, NW China, is the largest endorheic river basin in China and one of the largest in all of Central Asia. Due to the extremely arid climate, with an annual precipitation of less than 100 mm, the water supply along the Aksu and Tarim rivers solely depends on river water. This is linked to anthropogenic activities (e.g., agriculture) and natural and semi-natural ecosystems as both compete for water. The ongoing increase in water consumption by agriculture and other human activities in this region has been enhancing the competition for water between human needs and nature. Against this background, 11 German and 6 Chinese universities and research institutes have formed the consortium SuMaRiO (Sustainable Management of River Oases along the Tarim River; http://www.sumario.de), which aims to create a holistic picture of the availability of water resources in the Tarim River basin and the impacts on anthropogenic activities and natural ecosystems caused by the water distribution within the Tarim River basin. On the basis of the results from field studies and modeling approaches as well as from suggestions by the relevant regional stakeholders, a decision support tool (DST) will be implemented that will then assist stakeholders in balancing the competition for water, acknowledging the major external effects of water allocation to agriculture and to natural ecosystems. This consortium was formed in 2011 and is funded by the German Federal Ministry of Education and Research. As the data collection phase was finished this year, the paper presented here brings together the results from the fields from the disciplines of climate modeling, cryology, hydrology, agricultural sciences, ecology, geoinformatics, and social sciences in order to present a comprehensive picture of the effects of different water availability schemes on anthropogenic activities and natural ecosystems along the Tarim River. The second objective is to present the project structure of the whole consortium, the current status of work (i.e., major new results and findings), explain the foundation of the decision support tool as a key product of this project, and conclude with application recommendations for the region. The discharge of the Aksu River, which is the major tributary of the Tarim, has been increasing over the past 6 decades. From 1989 to 2011, agricultural area more than doubled: cotton became the major crop and there was a shift from small-scale to large-scale intensive farming. The ongoing increase in irrigated agricultural land leads to the increased threat of salinization and soil degradation caused by increased evapotranspiration. Aside from agricultural land, the major natural and semi-natural ecosystems are riparian (Tugai) forests, shrub vegetation, reed beds, and other grassland, as well as urban and peri-urban vegetation. Within the SuMaRiO cluster, focus has been set on the Tugai forests, with Populus euphratica as the dominant tree species, because these forests belong to the most productive and species-rich natural ecosystems of the Tarim River basin. At sites close to the groundwater, the annual stem diameter increments of Populus euphratica correlated with the river runoffs of the previous year. However, the natural river dynamics cease along the downstream course and thus hamper the recruitment of Populus euphratica. A study on the willingness to pay for the conservation of the natural ecosystems was conducted to estimate the concern of the people in the region and in China's capital. These household surveys revealed that there is a considerable willingness to pay for conservation of the natural ecosystems, with mitigation of dust and sandstorms considered the most important ecosystem service. Stakeholder dialogues contributed to creating a scientific basis for a sustainable management in the future.

Description: The Tarim River Basin, located in Xinjiang, NW China, is the largest endorheic river basin of China and one of the largest in whole Central Asia. Due to the extremely arid climate with an annual precipitation of less than 100 mm, the water supply along the Aksu and Tarim River solely depends on river water. This applies for anthropogenic activities (e.g. agriculture) as well as for the natural ecosystems so that both compete for water. The on-going increase of water consumption by agriculture and other human activities in this region has been enhancing the competition for water between human needs and nature. Against this background, 11 German and 6 Chinese universities and research institutes formed the consortium SuMaRiO (www.sumario.de), which aims at gaining a holistic picture of the availability of water resources in the Tarim River Basin and the impacts on anthropogenic activities and natural ecosystems caused by the water distribution within the Tarim River Basin. The discharge of the Aksu River, which is the major tributary to the Tarim, has been increasing over the past 6 decades due to enhanced glacier melt. Alone from 1989 to 2011, the area under agriculture more than doubled. Thereby, cotton became the major crop and there was a shift from small-scale farming to large-scale intensive farming. The major natural ecosystems along the Aksu and Tarim River are riparian ecosystems: Riparian (Tugai) forests, shrub vegetation, reed beds, and other grassland. Within the SuMaRiO Cluster the focus was laid on the Tugai forests, with Populus euphratica as dominant tree, because the most productive and species-rich natural ecosystems can be found among those forests. On sites with groundwater distance of less than 7.5 m the annual increments correlated with river runoffs of the previous year. But, the further downstream along the Tarim River, the more the natural river dynamics ceased, which impacts on the recruitment of Populus euphratica. Household surveys revealed that there is a considerable willingness to pay for conservation of those riparian forests with the mitigation of dust and sandstorms considered as the most important ecosystem service. This interdisciplinary project will result in a decision support tool (DST), build on the participation of regional stakeholders and models based on results and field experiments. This DST finally shall assist stakeholders in balancing the water competition acknowledging the major external effects of any water allocation.

Description: Climate policy needs to address the multidecadal to centennial time scale of climate change. Although the realization of short-term targets is an important first step, to be effective climate policies need to be conceived as long-term programs that will achieve a gradual transition to an essentially emission-free economy on the time scale of a century. This requires a considerably broader spectrum of policy measures than the primarily market-based instruments invoked for shorter term mitigation policies. A successful climate policy must consist of a dual approach focusing on both short-term targets and long-term goals