| 1. |
- Barshep, Yahkat, et al.
(författare)
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Non-breeding ecology of the Whinchat Saxicola rubetra in Nigeria
- 2012
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Ingår i: Ornis Svecica. - 1102-6812 .- 2003-2633. ; 22, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- This study on the non-breeding ecology of the Whinchat Saxicola rubetra was conducted in central Nigeria from February through April. The core site was at Gwafan (N09°53', E08°57'), an open scrubland located 10 km east of the city of Jos. The density of Whinchats at Gwafan was 0.58 individuals/ha, almost three times the overall density around Jos. Time budget observations of colour banded Whinchats, including six birds fitted with radio-transmitters, showed that they spent 80% of their time perching, 11% foraging, 7% preening, and 2% flying. The main method of catching insects was a swoop to the ground. There was no change in perching, preening or flying time but the time some Whinchats spent foraging increased towards the end of the study period. GPS positions of individuals showed that all birds held clearly demarcated territories and defended them against neighbours. Aggressive interactions were also recorded between Whinchats and other bird species. Three birds colour-ringed in 2006 returned to the study site in 2007 and one occupied almost the same territory, indicating site fidelity.
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| 2. |
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| 3. |
- Hellgren, Olof, et al.
(författare)
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Circannual variation in blood parasitism in a sub-Saharan migrant passerine bird, the garden warbler
- 2013
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 26:5, s. 1047-1059
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Tidskriftsartikel (refereegranskat)abstract
- Knowing the natural dynamics of pathogens in migratory birds is important, for example, to understand the factors that influence the transport of pathogens to and their transmission in new geographical areas, whereas the transmission of other pathogens might be restricted to a specific area. We studied haemosporidian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon in a migratory bird, the garden warbler Sylvia borin. Birds were sampled in spring, summer and early autumn at breeding grounds in Sweden, on migration at Capri, Italy and on arrival and departure from wintering staging areas in West Africa: mapping recoveries of garden warblers ringed in Fennoscandia and Capri showed that these sites are most probably on the migratory flyway of garden warblers breeding at Kvismaren. Overall, haemosporidian prevalence was 39%, involving 24 different parasite lineages. Prevalence varied significantly over the migratory cycle, with relatively high prevalence of blood parasites in the population on breeding grounds and at the onset of autumn migration, followed by marked declines in prevalence during migration both on spring and autumn passage. Importantly, we found that when examining circannual variation in the different lineages, significantly different prevalence profiles emerged both between and within genera. Our results suggest that differences in prevalence profiles are the result of either different parasite transmission strategies or coevolution between the host and the various parasite lineages. When separating parasites into common vs. rare lineages, we found that two peaks in the prevalence of rare parasites occur; on arrival at Swedish breeding grounds, and after the wintering period in Africa. Our results stress the importance of appropriate taxonomic resolution when examining host-parasite interactions, as variation in prevalence both between and within parasite genera can show markedly different patterns.
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| 4. |
- Jafri, Hassan M., et al.
(författare)
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Identification of vibrational signatures from short chains of interlinked molecule-nanoparticle junctions obtained by inelastic electron tunnelling spectroscopy
- 2013
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Ingår i: Nanoscale. - 2040-3364 .- 2040-3372. ; 5:11, s. 4673-4677
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Tidskriftsartikel (refereegranskat)abstract
- Short chains containing a series of metal- molecule-nanoparticle nanojunctions are a nano-materials system with the potential to give electrical signatures close to those from single molecule experiments while enabling to build portable devices on a chip. Inelastic electron tunnelling spectroscopy (IETS) measurements provide one of the most characteristic electrical signals of single and few molecules. In interlinked molecule-nanoparticle (NP) chains containing of typically 5-7 molecules in a chain, the spectrum is expected to be a superposition of the vibrational signature of individual molecules. We have established a stable and reproducible molecule-AuNP multi-junction by placing few 1,8-octanedithiol (ODT) molecules into a versatile and portable nanoparticle-nanoelectrode platform and measured for the first time vibrational molecular signatures complex and coupled few-molecule-NP junctions. From quantum transport calculations, we model the IETS spectra and identify vibrational modes as well as the number of molecules contributing to the electron transport in the measured spectra.
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| 5. |
- Jahn, Burkhard O., et al.
(författare)
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Organic Single Molecular Structures for Light Induced Spin-Pump Devices
- 2013
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 7:2, s. 1064-1071
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Tidskriftsartikel (refereegranskat)abstract
- We present theoretical results on molecular structures for realistic spin-pump applications. Taking advantage of the electron spin resonance concept, we find that interesting candidates constitute triplet biradicals with two strongly spatially and energetically separated singly occupied molecular orbitals (SOMOs). Building on earlier reported stable biradicals, particularly bis(nitronyl nitroxide) based biradicals, we employ density functional theory to design a selection of potential molecular spin-pumps which should be persistent at ambient conditions. We estimate that our proposed molecular structures will operate as spin-pumps using harmonic magnetic fields in the MHz regime and optical fields in the infrared to visible light regime.
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| 6. |
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| 7. |
- Månsson, Jonas, 1964-, et al.
(författare)
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Transitions from part-time unemployment: Is part-time job a dead end or a stepping stone?
- 2011
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Ingår i: Economic and Industrial Democracy. - 0143-831X .- 1461-7099. ; 32:4, s. 569-589
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Tidskriftsartikel (refereegranskat)abstract
- This article analyses the effects of individual characteristics on the probability of leaving part-time unemployment. The results show that it cannot be unreservedly asserted that part-time work offers access to the core labour market. Among the part-time unemployed, there are great variations in the degree to which they are likely to leave part-time unemployment. A concentration of labour market policy activities on the part-time unemployed who are least likely to succeed in finding full-time employment can, therefore, be expected to have positive consequences from both equity and efficiency points of view. In this respect, part-time unemployed women, persons with work-related disabilities and persons with temporary employment come to the forefront. The article shows that the likelihood of finding a full-time job is certainly not great for persons belonging to these groups. For many of them, part-time job is not a stepping stone but rather a dead end on the labour market.
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| 8. |
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| 10. |
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| 11. |
- Ottosson, Jonas
(författare)
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Thermal Modelling of Power Modules in a Hybrid Vehicle Application
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hybrid electric and full electric vehicles have attracted growing attention during the last decade. This is a consequence of several factors, such as growing environmental concerns, increasing oil prices and a strive for oil independency. Hybrid vehicles have proven to have significant potential to improve fuel economy and at the same time enhance the performance of the vehicle. For the hybrid cars to really penetrate the passenger car market, it is of vital importance that the cost of hybridization can be kept as low as possible and that the increased cost will be paid back within a reasonable time horizon. In addition to this, high reliability of the additional electrical drive system (EDS) needs to be ensured. The power electronics (PE) of the EDS is often packaged into some kind of standalone housing. An alternative solution is to integrate the power electronic inverter and the electric machine into one unit, sharing the same cooling system. This will reduce the packaging volume and at the same time omit the need for the expensive connectors and cables. The integration has other benefits such as, modularity and no separate housing for the inverter is required. All of the above mentioned benefits of the system integration lead to reduced costs of the system and in the long run a reduced price of the vehicle. However, integrating the PE and ETM into one unit makes the thermal design more difficult. This thesis focuses on determining the required cooling capacity of the cooling system, which is an important task, both from a reliability and cost perspective. Long lifetime or high reliability is important for customer acceptance. Performing simulations of power inverter systems, where both the electrical and thermal response is incorporated, often referred to as electro-thermal simulations, is a difficult task due to the different time scales of the two disciplines. If every switching instant is to be simulated, simulation times in the range of microseconds have to be used. Simulating inverter systems in a hybrid vehicle application, where driving cycles lasting for thousands of seconds normally is used, requires unreasonable simulation times. The thesis presents a method for solving this problem. Several electro-thermal simulations are carried out in order to determine the cooling requirements and its effect on module reliability of the inverter. The foundation for these simulations is a simulation model of the electrical drive system, where the main focus is on the thermal model of the inverter itself. The thesis presents a thermal model development procedure to derive simplified thermal models based on thermal impedances. Thermal models for a range of power modules, including both Si and SiC based modules, are presented. Different types of assemblies with single-sided cooling are thoroughly examined in the thesis. In addition to the different single-sided cooled module assemblies, one assembly with double-sided cooling is studied. The thesis shows that the type of layout and assembly greatly affects the thermal behaviour, and as a consequence the lifetime, of the power module. In addition to different module assemblies and cooling options, the system is evaluated for different driving cycles and cooling medium temperatures, together with a comparison of using a fixed and variable switching frequency. The thesis shows that using a variable switching frequency has a significant impact on the cooling requirements.
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| 12. |
- Ottosson, Lars-Göran, et al.
(författare)
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Sulfate assimilation mediates tellurite reduction and toxicity in Saccharomyces cerevisiae
- 2010
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Ingår i: Eukaryotic Cell. - 1535-9778 .- 1535-9786. ; 9:10, s. 1635-1647
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Tidskriftsartikel (refereegranskat)abstract
- Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism.
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| 13. |
- Ottosson, Mikael, 1980-, et al.
(författare)
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Configuring the 'industrial collective': : A controversy on the use of Swedish forests, 1989–2009
- 2011
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Ingår i: Paper presented at the 27th EGOS Colloquium Gothenburg 2011. ; , s. 1-31
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Konferensbidrag (refereegranskat)abstract
- We introduce a theoretical vocabulary highlighting a neglected area in industrial change theory, the outsider role. Industries cannot be fully examined without considering the influence of concerned groups, i.e. actors concerned with the industrial activity. Our empirical focus is a mature, stable, and highly homogeneous industrial sector, namely, the Swedish forest industry. We identify, analyse, and discuss the development and configuration of various truth claims and standpoints regarding the characteristics and potential uses of Sweden’s forest resources, 1989–2009. We follow the translation of the forest industry from producing solely pulp and paper products to producing electricity, heat, and bio-fuels. We argue that, without the pressure of concerned groups and ‘industrialists in the wild’ on the industry, forest industrial activity would never have been reconfigured.
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| 14. |
- Ottosson, Mikael
(författare)
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Opposition and adjustment to industrial ‘greening’ : the Swedish forest industry’s (re)actions regarding energy transition – 1989-2009
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis analyses how the Swedish forest industry has (re)acted regarding the energy transition and, in particular, regarding the reconstruction of the electricity and forest resources in Sweden during the 1989–2009 period. The thesis consists of four papers that analyse how the Swedish forest industry by means of energy management practices at individual pulp and/or paper mills, in corporate strategies performed by CEOs and boards of directors, and via its industry association, has dealt with mounting political and public demands for the industry to become ‘greener’. At the heart of the thesis are issues related to the industry’s substantial use and management of electricity and forest resources.This thesis focuses on the patterns of conflict and reconstruction that various forest industry representatives (e.g., CEOs) and entities (e.g., mills and resources) have experienced in relation to opposing and/or adjusting to the energy transition. The Swedish forest industry constitutes an illuminating case in a wider research context of how an industry (re)acts regarding increasing environmental and energy-related demands concerning its strategic resources. By using multidisciplinary theoretical concepts when analysing industrial change, this thesis demonstrates the industry’s wider embeddedness in science, policy, and material resources.
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| 15. |
- Samuelsson, Oscar, et al.
(författare)
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Pilotförsök med membranbioreaktor för avloppsvattenrening
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det finns ett växande intresse för kommunal avloppsvattenrening med membranteknik i Sverige. Fördelarna med membranteknik är att låga utsläpps- och partikelhalter kan uppnås på en liten anläggningsyta. Den största nackdelen är en ökad energi-förbrukning, på grund av den ökade luftning för rengöring av membranen och stora recirkulationsflöden som innebär ökad pumpenergi. Stockholm Vatten har beslutat att införa membranteknik i befintliga volymer på Henriksdal avloppsreningsverk. Detta för att klara både framtida skärpta utsläppskrav och en ökad belastning (fördubblad till år 2040, jämfört med dagens belastning). Ökningen orsakas av avvecklingen av Bromma reningsverk i kombination med en allmän befolkningstillväxt. Försök med en MembranBioReaktor (MBR) har under ett år genomförts på Hammarby Sjöstadsverk där en skalenlig pilotanläggning med membranteknik, Sjöstadsverkets Linje 1, har jämförts med en konventionell reningsanläggning, Henriksdal. Flödena under försöket motsvarade prognosticerade flöden för Henriksdal år 2040. Fyra olika driftsfall studerades i pilotförsöken där inflödet av avloppsvattnet varierade mellan: konstant medelflöde, dynamiskt medelflöde och maximalt flöde (förväntad maximal veckobelastning år 2040). Följande slutsatser kunde dras: Förväntade utsläppskrav, <0,2 mg/L Tot-P och <6 mg/L Tot-N, var möjliga att uppnå under minst en månad för samtliga driftsfall. Vid maximalt flöde tilläts en högre dos av både järnsulfat och kolkälla. Vid normal dosering av järnsulfat noterades ingen negativ effekt med fouling på membranen. Det fanns inte heller några indikationer på att förbrukningen av järnsulfat, vid normal dosering, skilde sig i MBR-systemet jämfört med Henriksdal. Vid maximala belastningsfallet doserades en högre halt järnsulfat vilket resulterade i låg utgående fosfathalt kring 0,1 mg/L. Det fanns dock en indikation på att förhållandet mellan avskild mängd fosfor per doserad mängd järn försämrades vid den högre dosen. Membranen hade en hög medelpermeabilitet och robust avskiljning av partikulärt material under hela försöksåret. Slammets filtrerbarhet analyserades med två mätmetoder inom ett examensarbete. Filtrerbarheten förbättrades under tiden som försöket pågick, och var god enligt mätmetodernas referensvärden. Membranen rengjordes med kemikalier, oxalsyra och natriumhypoklorit, vid fem tillfällen. Vid ett av dessa tillfällen analyserades halten klororganiska föreningar, AOX, i utgående vatten. AOX ökade under det dygn som rengöringen genomfördes från 0,03 till 0,6 mg/L i utgående vatten. Efterföljande dygn var halterna åter 0,03 mg/L. Det var möjligt att hålla en hög slamhalt i Sjöstadsverket Linje 1, 4000 -10 000 mg/L, genom hela försöket. Även den totala slamåldern var hög jämfört med traditionella system; 15-50 dygn. En jämförelse mellan slammets aktivitet; nitrifikations- och denitrifikationshastighet, visade dock att aktiviteten var lägre i MBR-systemet än i Henriksdal. Nitrifikation noterades i MBR-reaktoren vid belastningstoppar av ammonium. Detta gjorde att nitrifikationen, från systemet i sin helhet, var fullständig under hela försöksåret.
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| 16. |
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