| 1. |
- Högfeldt, Anna-Karin, et al.
(författare)
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Program Leadership from a Nordic Perspective
- 2012
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Ingår i: Proceedings of the 8th International CDIO Conference, Queensland University of Technology, Brisbane..
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Konferensbidrag (refereegranskat)
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| 2. |
- Mace, Georgina M., et al.
(författare)
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Approaches to defining a planetary boundary for biodiversity
- 2014
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Ingår i: Global Environmental Change. - : Elsevier BV. - 0959-3780 .- 1872-9495. ; 28, s. 289-297
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Tidskriftsartikel (refereegranskat)abstract
- The idea that there is an identifiable set of boundaries, beyond which anthropogenic change will put the Earth system outside a safe operating space for humanity, is attracting interest in the scientific community and gaining support in the environmental policy world. Rockstrom et al. (2009) identify nine such boundaries and highlight biodiversity loss as being the single boundary where current rates of extinction put the Earth system furthest outside the safe operating space. Here we review the evidence to support a boundary based on extinction rates and identify weaknesses with this metric and its bearing on humanity's needs. While changes to biodiversity are of undisputed importance, we show that both extinction rate and species richness are weak metrics for this purpose, and they do not scale well from local to regional or global levels. We develop alternative approaches to determine biodiversity loss boundaries and extend our analysis to consider large-scale responses in the Earth system that could affect its suitability for complex human societies which in turn are mediated by the biosphere. We suggest three facets of biodiversity on which a boundary could be based: the genetic library of life; functional type diversity; and biome condition and extent. For each of these we explore the science needed to indicate how it might be measured and how changes would affect human societies. In addition to these three facets, we show how biodiversity's role in supporting a safe operating space for humanity may lie primarily in its interactions with other boundaries, suggesting an immediate area of focus for scientists and policymakers.
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| 3. |
- Alexiadis, Alessio, et al.
(författare)
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Liquid-gas flow patterns in a narrow electrochemical channel
- 2011
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509 .- 1873-4405. ; 66:10, s. 2252-2260
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Tidskriftsartikel (refereegranskat)abstract
- The flow in a narrow (3 mm wide) vertical gap of an electrochemical cell with gas evolution at one electrode is modeled by means of the two-phase Euler-Euler model. The results indicate that at certain conditions an unsteady type of flow with vortices and recirculation regions can occur. Such flow pattern has been observed experimentally, but not reported in previous modeling studies. Further analysis establishes that the presence of a sufficient amount of small (similar to 10 mu m) bubbles is the main factor causing this type of flow at high current densities.
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| 4. |
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| 5. |
- Alexiadis, Alessio, et al.
(författare)
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The flow pattern in single and multiple submerged channels with gas evolution at the electrodes
- 2012
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Ingår i: International Journal of Chemical Engineering. - : Hindawi Limited. - 1687-806X .- 1687-8078. ; 2012, s. 392613-
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Tidskriftsartikel (refereegranskat)abstract
- We show that the gas-liquid flow pattern in a single gas-evolving electrochemical channel can be remarkably different from the flow pattern in multiple submerged gas-evolving electrochemical channels. This is due to the fact that in a single channel there is a higher accumulation of small bubbles and these can considerably affect the liquid velocity pattern which in turn may affect the performance of a cell. Since experimental work is often carried out in single channels, while industrial applications almost always involve multiple channels, this study provides insight into the factors that affect the flow pattern in each situation and establishes the basis for relating the behavior of single-and multiple-channel devices.
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| 6. |
- Alexiadis, Alessio, et al.
(författare)
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Transition to pseudo-turbulence in a narrow gas-evolving channel
- 2012
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Ingår i: Theoretical and Computational Fluid Dynamics. - : Springer Science and Business Media LLC. - 0935-4964 .- 1432-2250. ; 26:6, s. 551-564
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Tidskriftsartikel (refereegranskat)abstract
- Different flow regimes have been observed, both experimentally and in CFD simulations, in narrow channels with gas evolution. In this manuscript, we examine, using the Euler-Euler model, the flow in a narrow channel, where gas is evolved from a vertical wall. We find some pseudo-turbulent features at conditions described in this manuscript. The transition to this pseudo-turbulent regime is associated with the value of a specific dimensionless group.
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| 7. |
- Byrne, Myles, et al.
(författare)
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VarioML framework for comprehensive variation data representation and exchange
- 2012
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Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 13:254
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sharing of data about variation and the associated phenotypes is a critical need, yet variant information can be arbitrarily complex, making a single standard vocabulary elusive and re-formatting difficult. Complex standards have proven too time-consuming to implement. Results: The GEN2PHEN project addressed these difficulties by developing a comprehensive data model for capturing biomedical observations, Observ-OM, and building the VarioML format around it. VarioML pairs a simplified open specification for describing variants, with a toolkit for adapting the specification into one's own research workflow. Straightforward variant data can be captured, federated, and exchanged with no overhead; more complex data can be described, without loss of compatibility. The open specification enables push-button submission to gene variant databases (LSDBs) e. g., the Leiden Open Variation Database, using the Cafe Variome data publishing service, while VarioML bidirectionally transforms data between XML and web-application code formats, opening up new possibilities for open source web applications building on shared data. A Java implementation toolkit makes VarioML easily integrated into biomedical applications. VarioML is designed primarily for LSDB data submission and transfer scenarios, but can also be used as a standard variation data format for JSON and XML document databases and user interface components. Conclusions: VarioML is a set of tools and practices improving the availability, quality, and comprehensibility of human variation information. It enables researchers, diagnostic laboratories, and clinics to share that information with ease, clarity, and without ambiguity.
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| 8. |
- Cornell, David H., 1948, et al.
(författare)
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Dwyka cobbles reveal Archean basement beneath the Kalahari sands.
- 2011
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Ingår i: 23rd Colloquium African Geology, University of Johannesburg, January 2011, Abstracts.
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Konferensbidrag (refereegranskat)abstract
- We have found a new source of information about what lies beneath the Kalahari sands. The regions known as the Kheis and Rehoboth Provinces were thought to be underlain by either an ~1800 Ma orogenic belt, or a northern branch of the ~1200 Ma Namaqua-Natal Province, now largely covered by Cretaceous to Recent sand. Glacial diamictites of the Permian Dwyka Group exposed at Rietfontein west of the Kalahari carry cobbles plucked from the bedrock by the ice sheet which covered the Gondwana supercontinent about 300 Ma ago. Microbeam U-Pb zircon dating of the granitic cobbles shows that they contain no evidence of crustal growth or orogeny at either 1800 or 1200 Ma. Rather they testify to the presence of 2500 to 2900 Ma Archean crust beneath the Kalahari, with a lesser ~2050 Ma component, coeval with the Bushveld complex of the Kaapvaal Craton to the east. The mafic cobbles are much younger and are related to intrusions of the 1.1 Ga Umkondo Large Igneous Province along the Kalahari Line. Oxygen isotope analyses of zircon from the cobbles and western Kaapvaal Craton granites show a surprising difference, supporting the lithostratigraphic evidence that the granite cobbles do not originate from as far east as the Kaapvaal Craton. All the cobbles are most likely derived from either the Kalahari Line or the Rehoboth Province, whereas origins in the Kheis Province and Kaapvaal Craton are considered unlikely. The possible existence of Archean crust in the Rehoboth Province has important implications not only for the tectonic framework and assembly of Southern Africa, but also for exploration for diamonds and other ore deposits.
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| 9. |
- Cornell, David H., 1948, et al.
(författare)
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Evidence from Dwyka tillite cobbles of Archean basement beneath the Kalahari sands of southern Africa
- 2011
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Ingår i: Lithos. - 0024-4937. ; 125, s. 482-502
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Tidskriftsartikel (refereegranskat)abstract
- We have found a new source of information about what lies beneath the Kalahari sands. The Kheis and Rehoboth Provinces of southern Africa were thought to be underlain by either an ~1800 Ma orogenic belt, or a northern branch of the ~1200 Ma Namaqua–Natal Province. Glacial diamictites of the Permocarboniferous Dwyka Group exposed at Rietfontein west of the Kalahari sands carry cobbles plucked from the bedrock by the ice sheet which covered the Gondwana supercontinent about 300 Ma ago. Despite altered mineralogy, the cobbles are not severely altered geochemically. Their normative mineral compositions give classifications as trondhjemites and granites, supported by rare earth element diagrams. Microbeam U–Pb zircon dating of the granitic cobbles shows that they contain no evidence of crustal growth or orogeny at either 1800 or 1200 Ma. Rather they testify to the presence of 2500 to 2900 Ma Archaean trondhjemitic and granitic crust beneath the Kalahari, with a lesser ~2050 Ma granite component. The pebble assemblages from the diamictites we sampled lack the diagnostic banded iron formation (BIF), stromatolitic limestone and other supracrustal pebbles which characterise diamictites derived from the Kaapvaal Craton, thus we envisage shorter transport distances and derivation from the region now beneath the Kalahari sands. Three of the Archaean granite cobbles have unusual less-than-mantle zircon oxygen isotope values around +3 (δ18O VSMOW), which may reflect interaction of their source with high-temperature, originally meteoric water before melting to produce the granites. The mafic cobbles described in a companion paper are much younger and are related to intrusions of the 1.1 Ga Umkondo Large Igneous Province, probably located on the Kalahari Line or Rehoboth Province. Five trondhjemitic granites from the westernmost outcrops of the Kaapvaal Craton were dated, the oldest being 3061±9 Ma and four others between 2882±7 Ma and 2854±7 Ma, reflecting the cratonisation of the Kimberley Terrane. Four of the Archaean Dwyka cobbles we dated are younger than the 2.7 Ga Kaapvaal cover sequence and are thus too young to be derived from the craton. All the Dwyka cobbles described here are most likely derived from either the Rehoboth Province or the Kalahari Line with origins from the Kheis Province, Kaapvaal Craton, or further afield considered unlikely. We envisage the Rehoboth Province to consist of an Archaean core supplemented by Palaeoproterozoic granitoids, which was joined to the Kaapvaal Craton at an early stage of crustal development and played an important role during later tectonic events. This has important implications not only for the tectonic framework and assembly of Southern Africa, but also for exploration for diamonds and other ore deposits.
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| 10. |
- Dearing, John A., et al.
(författare)
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Safe and just operating spaces for regional social-ecological systems
- 2014
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Ingår i: Global Environmental Change. - : Elsevier BV. - 0959-3780 .- 1872-9495. ; 28, s. 227-238
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Tidskriftsartikel (refereegranskat)abstract
- Humanity faces a major global challenge in achieving wellbeing for all, while simultaneously ensuring that the biophysical processes and ecosystem services that underpin wellbeing are exploited within scientifically informed boundaries of sustainability. We propose a framework for defining the safe and just operating space for humanity that integrates social wellbeing into the original planetary boundaries concept (Rockstrom et al., 2009a,b) for application at regional scales. We argue that such a framework can: (1) increase the policy impact of the boundaries concept as most governance takes place at the regional rather than planetary scale; (2) contribute to the understanding and dissemination of complexity thinking throughout governance and policy-making; (3) act as a powerful metaphor and communication tool for regional equity and sustainability. We demonstrate the approach in two rural Chinese localities where we define the safe and just operating space that lies between an environmental ceiling and a social foundation from analysis of time series drawn from monitored and palaeoecological data, and from social survey statistics respectively. Agricultural intensification has led to poverty reduction, though not eradicated it, but at the expense of environmental degradation. Currently, the environmental ceiling is exceeded for degraded water quality at both localities even though the least well-met social standards are for available piped water and sanitation. The conjunction of these social needs and environmental constraints around the issue of water access and quality illustrates the broader value of the safe and just operating space approach for sustainable development.
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| 11. |
- Jickells, T., et al.
(författare)
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The cycling of organic nitrogen through the atmosphere
- 2013
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 368:1621
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Forskningsöversikt (refereegranskat)abstract
- Atmospheric organic nitrogen (ON) appears to be a ubiquitous but poorly understood component of the atmospheric nitrogen deposition flux. Here, we focus on the ON components that dominate deposition and do not consider reactive atmospheric gases containing ON such as peroxyacyl nitrates that are important in atmospheric nitrogen transport, but are probably not particularly important in deposition. We first review the approaches to the analysis and characterization of atmospheric ON. We then briefly summarize the available data on the concentrations of ON in both aerosols and rainwater from around the world, and the limited information available on its chemical characterization. This evidence clearly shows that atmospheric aerosol and rainwater ON is a complex mixture of material from multiple sources. This synthesis of available information is then used to try and identify some of the important sources of this material, in particular, if it is of predominantly natural or anthropogenic origin. Finally, we suggest that the flux of ON is about 25 per cent of the total nitrogen deposition flux.
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| 12. |
- Mohammad, Yousif, 1976, et al.
(författare)
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Geochemistry and Ar-Ar muscovite ages of the Daraban Leucogranite, Mawat ophiolite, northeastern Iraq: Implications for Arabia-Eurasia continental collision
- 2014
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Ingår i: Journal of Asian Earth Sciences. - : Elsevier BV. - 1367-9120. ; 86, s. 151-165
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Tidskriftsartikel (refereegranskat)abstract
- Daraban Leucogranite dykes intruded discordantly into the basal serpentinized harzburgite of the Mawat Ophiolite, Kurdistan region, NE Iraq. These coarse grained muscovite-tourmaline leucogranites are the first leucogranite dykes identified within the Mawat Ophiolite. They are mainly composed of quartz, K-feldspar, plagioclase, tourmaline, muscovite, and secondary phologopite, while zircon, xenotime, corundum, mangano-ilemnite and cassiterite occur as accessories. The A/CNK value of the granite dyke samples varies from 1.10 to 1.22 indicating a strongly peraluminous composition. CaO/Na2O ranges from 0.11 to 0.15 and Al2O3/TiO2 from 264 to 463, similar to the strongly peraluminous (SP) granites exposed in ‘high-pressure’ collision zones such as the Himalayas. Ar–Ar muscovite step-heating dating yields 37.57 ± 0.25 and 38.02 ± 0.53 Ma plateau ages for two samples which are thought to reflect either their magmatic emplacement or resetting during collision-related metamorphism. Mineral chemistry shows evidence of both primary and secondary types of muscovite, with cores favouring the magmatic interpretation and slight effects of a late syn-serpentinization fluid seen at the rims. Geochemical features of Daraban Leucogranite dykes favour a syn-collisional tectonic setting. They probably formed in response to the continental collision between Eurasia and Arabia during the initial stage of the opening of the Gulf of Aden at 37 Ma. The muscovite ages and geochemical features of Daraban Leucogranite are strong evidence for the timing of the continental collision between northeastern Arabia and Eurasia in Kurdistan region of Iraq.
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| 13. |
- Peyrard-Janvid, Myriam, et al.
(författare)
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Dominant Mutations in GRHL3 Cause Van der Woude Syndrome and Disrupt Oral Periderm Development
- 2014
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 94:1, s. 23-32
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in interferon regulatory factor 6 (IRF6) account for similar to 70% of cases of Van der Woude syndrome (VWS), the most common syndromic form of cleft lip and palate. In 8 of 45 VWS-affected families lacking a mutation in IRF6, we found coding mutations in grainyhead-like 3 (GRHL3). According to a zebrafish-based assay, the disease-associated GRHL3 mutations abrogated periderm development and were consistent with a dominant-negative effect, in contrast to haploinsufficiency seen in most VWS cases caused by IRF6 mutations. In mouse, all embryos lacking Grhl3 exhibited abnormal oral periderm and 17% developed a cleft palate. Analysis of the oral phenotype of double heterozygote (Irf6(+/-);Grhl3(+/-)) murine embryos failed to detect epistasis between the two genes, suggesting that they function in separate but convergent pathways during palatogenesis. Taken together, our data demonstrated that mutations in two genes, IRF6 and GRHL3, can lead to nearly identical phenotypes of orofacial cleft. They supported the hypotheses that both genes are essential for the presence of a functional oral periderm and that failure of this process contributes to VWS.
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| 14. |
- Sjöqvist, Axel S.L. 1990, et al.
(författare)
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Geochronology of the Norra Kärr alkaline complex, southern Sweden
- 2014
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Ingår i: 31st Nordic Geological Winter Meeting.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Norra Kärr alkaline complex is a small intrusion of agpaitic nepheline syenite, located approximately 10 km north of Grän- na, southern Sweden, that is being explored for REE and Zr. Agpaitic nepheline syenites per definition do not contain simple Zr minerals like zircon and baddeleyite, despite generally high Zr contents (up to 1–2 wt.% ZrO2). Instead, Zr is mainly hosted in rock-forming complex Na-Ca-Zr silicate minerals such as members of the catapleiite, eudialyte, rosenbuschite, and wöhlerite groups. U-Pb zircon geochronology is thus highly impeded by the agpaitic nature. We established a new, reliable igneous age for the Norra Kärr alkaline complex at 1489±8 Ma (MSWD = 0.95) by dating zircons (U-Pb) in the country rocks that were affected by the magmatism-related alkaline alteration (fenitisation) by LA-MC-ICP-MS. Zircons from a satellite body of non-agpaitic syenite gave intercept ages within error of the age of fenitisation. This is an improvement upon an imprecise whole-rock Rb-Sr age of 1545±61 Ma (Blaxland 1977; Welin 1980). The non-fenitised country granite itself is dated at 1781±8 Ma (MSWD = 0.59), and thus belongs to the TIB1 (1.81–1.76 Ga) episode of the Transscandinavian Igneous Belt (TIB). Rare zircon xenocrysts extracted from the nepheline syenite show ages corresponding to 1.5 Ga lower crustal intrusives (rapakivi?), TIB, Svecofennian, and one Archaean zircon, which suggests the possibility for a remnant of Archaean basement below the TIB. There has historically been a vivid discussion about wheth- er or not Norra Kärr has been deformed and metamorphosed. New Ar-Ar step heating ages on sodic amphibole from Norra Kärr and muscovite and biotite from the country rocks give plateau ages at 1.1 Ga and 0.94 Ga, which correspond to ages derived for Sveconorwegian shear zones in the area. Together with textural and crystal chemical evidence, these ages make a compelling argument for some form of Sveconorwegian overprint of the Norra Kärr alkaline complex.
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| 15. |
- Sörlin, Sverker, et al.
(författare)
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Toward an Integrated History to Guide the Future
- 2011
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Ingår i: Ecology and Society. - 1708-3087. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- Many contemporary societal challenges manifest themselves in the domain of human–environment interactions.There is a growing recognition that responses to these challenges formulated within current disciplinary boundaries, in isolationfrom their wider contexts, cannot adequately address them. Here, we outline the need for an integrated, transdisciplinary synthesisthat allows for a holistic approach, and, above all, a much longer time perspective. We outline both the need for and thefundamental characteristics of what we call “integrated history.” This approach promises to yield new understandings of therelationship between the past, present, and possible futures of our integrated human–environment system. We recommend aunique new focus of our historical efforts on the future, rather than the past, concentrated on learning about future possibilitiesfrom history. A growing worldwide community of transdisciplinary scholars is forming around building this Integrated Historyand future of People on Earth (IHOPE). Building integrated models of past human societies and their interactions with theirenvironments yields new insights into those interactions and can help to create a more sustainable and desirable future. Theactivity has become a major focus within the global change community.
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| 16. |
- van Schijndel, Valby, et al.
(författare)
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Crustal evolution of the Rehoboth Province from Archaean to Mesoproterozoic times: Insights from the Rehoboth Basement Inlier
- 2014
-
Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 240, s. 22-36
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Tidskriftsartikel (refereegranskat)abstract
- The Rehoboth Province of southern Africa is defined by its smooth magnetic character by contrast to the adjoining mobile belts. It has been slow to yield information about its crustal evolution because most of it is covered by Kalahari sands. A combined microbeam study of U-Pb, Lu-Hf in zircon from metasedimentary and magmatic rocks of the well-exposed Rehoboth Basement Inlier (RBI) provides new constraints on the crustal evolution of the Rehoboth Province. The detrital zircons provide evidence for five U-Pb age groups corresponding to magmatic events within the crust, whereas Lu-Hf zircon data allows estimates of crustal residence age. Zircon oxygen isotope data for the magmatic rocks implies diversity in their genesis. The sparse 3.41-2.45 Ga U-Pb zircon age group I (6 zircons) strengthens the concept of an Archaean foundation to the Rehoboth Province, previously suggested from kimberlite xenoliths and granitic cobbles transported by the Dwyka icesheet from further south in the Rehoboth Province. Detrital age group II from 2.15 to 1.92 Ga has not been identified in outcropping magmatic rocks. However several Dwyka cobbles have 2.05 ages, similar to the Bushveld Complex and thermal event seen in the adjoining Kaapvaal Craton. This suggests that the Rehoboth Province may already have been attached to the Kaapvaal Craton at this time. Age group II has Lu-Hf isotope character requiring mixing between Archaean crustal source rocks and juvenile mantle material. Age group III (1.92-1.83 Ma) corresponds in age to the largely metabasaltic 1870 +/- 6 Ma Elim Formation, now the oldest dated unit in the RBI. The detrital Lu-Hf data again requires an Archaean crustal source mixing with mantle-derived material. However the magmatic Elim Formation zircons originated from a distinctly more juvenile source than the detrital zircons of the same age (group III), and they have a low mantle delta O-18(zrc) value of 4.83 (assuming mantle 5.3 +/- 0.6). This suggests a mantle or lower oceanic crustal affinity for the Elim Formation, whereas the detrital zircons may have come from a more evolved crustal source located in the continental hinterland. Detrital age group IV (1.83-1.61 Ga) corresponds to eight precisely dated volcanic and plutonic rocks which have similar Lu-Hf character and probably provided the detrital zircons. Zircon oxygen isotope values for the magmatic rocks show a considerable range. The sub-mantle values of the 1826 +/- 5 Ma Kalkbrak Gneiss and 1753 +/- 6 Ma Marienhof meta-rhyolites (delta O-18(zrc) 4.30 and 4.31 respectively) are thought to have originated from the same low-delta O-18 crustal source as the Elim Formation. Three other samples in this group show a trend to higher delta O-18 values, culminating in a high value of delta O-18(zrc) 9.35 +/- 0.53 for the 1769 +/- 6 Ma Gaub Valley andesitic, volcanoclastic sample. This trend is thought to reflect addition of low-T altered supracrustal material or high delta O-18 metasomatic fluids to the source rocks in a geochemically documented subduction setting. The broad detrital age group V (1.33-1.09 Ga), found in the one <= 1.1 Ga Langberg Formation metasediment investigated, reflects the entire Namaqua Wilson Cycle including rifting and drifting, arc processes, 1.2 Ga collision and the post-tectonic 1.1 Ga Umkondo plume event. This group shows a large spread of Lu-Hf crustal residence ages from 2.3 to 1.45 Ga, reflecting a mixture of sources from Archaean to juvenile Namaqua crust. A 1221 +/- 6 Ma Gamsberg Granite sample showed 2.2-2.0 Ga crustal residence ages and mantle-like delta O-18(zrc) of 4.99, suggesting that its source was melted Palaeoproterozoic lower crust. Part of the group V detrital zircon population is not known as magmatic rocks in the RBI and was probably derived from the collisional mountain belt in the Namaqua Province to the west of the Rehoboth Province. The Rehoboth Province is thus revealed as an ancient crustal block with possible Archaean foundations, major Palaeoproterozoic events involving mantle additions mixed with reworked Archaean crust, and involving a number of different tectonic settings, culminating with the entire Mesoproterozoic Namaqua Wilson Cycle. (C) 2013 Elsevier B.V. All rights reserved.
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