2 results
Search Results
Now showing 1 - 2 of 2
- ItemChallenges in network science: Applications to infrastructures, climate, social systems and economics(Heidelberg : Springer, 2012) Havlin, S.; Kenett, D.Y.; Ben-Jacob, E.; Bunde, A.; Cohen, R.; Hermann, H.; Kantelhardt, J.W.; Kertész, J.; Kirkpatrick, S.; Kurths, J.; Portugali, J.; Solomon, S.Network theory has become one of the most visible theoretical frameworks that can be applied to the description, analysis, understanding, design and repair of multi-level complex systems. Complex networks occur everywhere, in man-made and human social systems, in organic and inorganic matter, from nano to macro scales, and in natural and anthropogenic structures. New applications are developed at an ever-increasing rate and the promise for future growth is high, since increasingly we interact with one another within these vital and complex environments. Despite all the great successes of this field, crucial aspects of multi-level complex systems have been largely ignored. Important challenges of network science are to take into account many of these missing realistic features such as strong coupling between networks (networks are not isolated), the dynamics of networks (networks are not static), interrelationships between structure, dynamics and function of networks, interdependencies in given networks (and other classes of links, including different signs of interactions), and spatial properties (including geographical aspects) of networks. This aim of this paper is to introduce and discuss the challenges that future network science needs to address, and how different disciplines will be accordingly affected.
- ItemA European aerosol phenomenology - 7: High-time resolution chemical characteristics of submicron particulate matter across Europe(Amsterdam : Elsevier, 2021) Bressi, M.; Cavalli, F.; Putaud, J.P.; Fröhlich, R.; Petit, J.-E.; Aas, W.; Äijälä, M.; Alastuey, A.; Allan, J.D.; Aurela, M.; Berico, M.; Bougiatioti, A.; Bukowiecki, N.; Canonaco, F.; Crenn, V.; Dusanter, S.; Ehn, M.; Elsasser, M.; Flentje, H.; Graf, P.; Green, D.C.; Heikkinen, L.; Hermann, H.; Holzinger, R.; Hueglin, C.; Keernik, H.; Kiendler-Scharr, A.; Kubelová, L.; Lunder, C.; Maasikmets, M.; Makeš, O.; Malaguti, A.; Mihalopoulos, N.; Nicolas, J.B.; O'Dowd, C.; Ovadnevaite, J.; Petralia, E.; Poulain, L.; Priestman, M.; Riffault, V.; Ripoll, A.; Schlag, P.; Schwarz, J.; Sciare, J.; Slowik, J.; Sosedova, Y.; Stavroulas, I.; Teinemaa, E.; Via, M.; Vodička, P.; Williams, P.I.; Wiedensohler, A.; Young, D.E.; Zhang, S.; Favez, O.; Minguillón, M.C.; Prevot, A.S.H.Similarities and differences in the submicron atmospheric aerosol chemical composition are analyzed from a unique set of measurements performed at 21 sites across Europe for at least one year. These sites are located between 35 and 62°N and 10° W – 26°E, and represent various types of settings (remote, coastal, rural, industrial, urban). Measurements were all carried out on-line with a 30-min time resolution using mass spectroscopy based instruments known as Aerosol Chemical Speciation Monitors (ACSM) and Aerosol Mass Spectrometers (AMS) and following common measurement guidelines. Data regarding organics, sulfate, nitrate and ammonium concentrations, as well as the sum of them called non-refractory submicron aerosol mass concentration ([NR-PM1]) are discussed. NR-PM1 concentrations generally increase from remote to urban sites. They are mostly larger in the mid-latitude band than in southern and northern Europe. On average, organics account for the major part (36–64%) of NR-PM1 followed by sulfate (12–44%) and nitrate (6–35%). The annual mean chemical composition of NR-PM1 at rural (or regional background) sites and urban background sites are very similar. Considering rural and regional background sites only, nitrate contribution is higher and sulfate contribution is lower in mid-latitude Europe compared to northern and southern Europe. Large seasonal variations in concentrations (μg/m³) of one or more components of NR-PM1 can be observed at all sites, as well as in the chemical composition of NR-PM1 (%) at most sites. Significant diel cycles in the contribution to [NR-PM1] of organics, sulfate, and nitrate can be observed at a majority of sites both in winter and summer. Early morning minima in organics in concomitance with maxima in nitrate are common features at regional and urban background sites. Daily variations are much smaller at a number of coastal and rural sites. Looking at NR-PM1 chemical composition as a function of NR-PM1 mass concentration reveals that although organics account for the major fraction of NR-PM1 at all concentration levels at most sites, nitrate contribution generally increases with NR-PM1 mass concentration and predominates when NR-PM1 mass concentrations exceed 40 μg/m³ at half of the sites. © 2021 The Authors