1. |
- Beckwith, O., et al.
(författare)
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Nonholomorphic Ramanujan-type congruences for Hurwitz class numbers
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:36, s. 21953-21961
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Tidskriftsartikel (refereegranskat)abstract
- In contrast to all other known Ramanujan-type congruences, we discover that Ramanujan-type congruences for Hurwitz class numbers can be supported on nonholomorphic generating series. We establish a divisibility result for such nonholomorphic congruences of Hurwitz class numbers. The two key tools in our proof are the holomorphic projection of products of theta series with a Hurwitz class number generating series and a theorem by Serre, which allows us to rule out certain congruences.
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2. |
- Bouchouireb, Hamza, 1991-, et al.
(författare)
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The inclusion of End-Of-Life modelling in the Life Cycle Energy Optimisation methodology
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this work, an End-Of-Life (EOL) model is included in the Life Cycle Energy Optimisation (LCEO) methodology to account for the energy burdens and credits stemming from a vehicle’s EOL processing phase and balance them against the vehicle’s functional requirements and production and use phase energies. The substitution with a correction factor allocation method is used to model the contribution of recycling to the EOL phase’s energy. The methodology is illustrated through the optimisation of the design of a simplified vehicle sub-system. For the latter, multiple recycling scenarios with varying levels of assumed recycling induced material property degradation were built, and their impact on the vehicle sub-system’s optimal solutions was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can significantly alter material use patterns thereby effecting the life cycle energy of the optimal designs. Indeed, the vehicle sub-system’s optimal designs associated with the recycling scenarios are on average substantially heavier, and less life cycle energy demanding, than their landfilling or incineration with energy recovery-related counterparts.
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3. |
- Burström, Thommie, 1964-
(författare)
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Organizing boundaries in early phases of product development : The case of an interorganizational vehicle platform project setting
- 2011
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Ingår i: International Journal of Managing Projects in Business/Emerald. - London : Emerald Group Publishing Limited. - 1753-8378 .- 1753-8386. ; 4:4, s. 697-710
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The purpose of this paper is to describe and to summarize a PhD thesis that contributes to the understanding of how boundaries are organized in early phases of new product development. The thesis explores the reality of project member's attempts to create a shared vehicle platform. The author also reports his PhD “journey”. Design/methodology/approach – Research reported here is based on a qualitative study through combinations of interviews, observations, and document studies. Data were gathered during three months at two different sites in two different countries. A practice approach was implemented where the daily work activities of project members were studied. Findings – It was concluded that organizing of boundaries should be understood as being affected by tensions and characterized by iterations that cross all types of organizational boundaries. The theory of Concurrent Boundary Enactment is therefore proposed as an answer to how the organizing of boundaries should be understood. Research limitations/implications – The study shows how project members in parallel organize technologies, structural units, and work processes. Thus, the study focuses on the complexity of organizing boundaries. There is a need to perform more of this type of practice-based, high complexity studies so that more profound organizing patterns can be understood. Practical implications – Actors in projects are closely attached to brands' core values. This core value attachment should be seen as both at strength and a weakness. It is seen as strength because core value attachment calls for compassion and dedication. It is seen as weakness since this type of attachment also makes it difficult to create synergies between brands. Therefore, brand managers should try to find least common nominators that bring together dispersed brand value statements. Originality/value – By studying multiple boundaries between functions, projects, projects and the permanent organization, projects and steering committees, projects and external organizations, it has been possible to illustrate the everyday complexity which follows by creating a shared vehicle platform between two organizations that compete and collaborate at the same time. Earlier research studies usually only concern one of the boundaries.
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5. |
- Hugander, A., et al.
(författare)
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Total body hyperthermia induced by a computerized microwave technique : studies in normal rats and in rats with liver tumors.
- 1983
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Ingår i: Anticancer research. - 0250-7005. ; 3:3, s. 161-165
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Tidskriftsartikel (refereegranskat)abstract
- A computerized system for inducing total body hyperthermia by microwave irradiation was tested in rats. The tolerance to hyperthermia at different temperatures and fractions was studied as well as its effect on the growth of transplanted adenocarcinomas in the liver. Survival results indicated that 41.5 degrees C was maximum tolerated temperature both after single and repeated one hour exposures. Besides the high mortality with a greater temperature (42 degrees C) there was a significant rise in S-aspartate-amino-transferase (S-ASAT) and S-beta-hexosaminidase (beta-nagas) indicating damage of normal cells. No significant reduction of tumor volume could be registered after treatment with total body hyperthermia (41.5 degrees C) for one hour three times during a 24 hour period.
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6. |
- Lemessa, Debissa, et al.
(författare)
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Tree cover mediates the effect on rapeseed leaf damage of excluding predatory arthropods, but in an unexpected way
- 2015
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Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 211, s. 57-64
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Tidskriftsartikel (refereegranskat)abstract
- Birds and predatory arthropods are often implicated in pest control, but their relative impact and how this is mediated by variation in tree cover requires elucidation. We excluded birds and ground predatory arthropods from rapeseed plants in 2.5 x 1 m plots in 26 homegardens in Ethiopia, leaving the same sized control plots. From six groups of plants in bird exclosure and control plots, respectively, three groups were excluded from ground predatory arthropods. Data on leaf damage were surveyed four times at weekly intervals. The tree cover and land-use composition within 100 x 100 m surrounding each plots were recorded in the field and from a satellite image within 200 and 500 m buffer zones. The results show that the mean leaf damage was higher on rapeseed plants from which predatory arthropods were excluded than on control plants. However, excluding birds had no or only a weak impact on leaf damage. The mean leaf damage within predatory arthropod exclosures decreased with increasing tree, forest and perennial cover but increased with increasing grazing land cover and annual crop cover, while on control plants it was low across the tree cover variation. This pattern may indicate the presence of a higher density of herbivores on rapeseed plants and also more predatory arthropods (i.e., to control them) in tree-poor homegardens compared to tree-rich homegardens. Hence, tree-poor homegardens in this landscape have sufficient habitat heterogeneity to support natural enemies to deliver significant pest control on rapeseed. Our results show that there was variation in the dynamics of pests and predatory arthropods across the tree cover variation, suggesting changes in landscape composition could affect the pest control services and the outcomes for local farmers.
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8. |
- Melber, Henning, 1950-
(författare)
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The Struggle Continues : Namibia's Enduring Land Question
- 2022
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Ingår i: Capital Penetration and the Peasantry in Southern and Eastern Africa. - Cham : Springer. - 9783030898236 - 9783030898267 - 9783030898243 ; , s. 79-99
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Bokkapitel (refereegranskat)
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9. |
- Merced Montero-Campillo, M., et al.
(författare)
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Gas-phase reactivity tuned through the interaction with alkaline-earth derivatives
- 2019
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Ingår i: Theoretical Chemistry accounts. - : Springer Science and Business Media LLC. - 1432-881X .- 1432-2234. ; 138:5
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Tidskriftsartikel (refereegranskat)abstract
- The cooperativity between MX2:XH alkaline-earth bonds and XH:NH3 hydrogen bonds (M=Mg, Ca; X=F, Cl) was investigated at the G4 level of theory. The cooperativity between these two non-covalent linkages is extremely large, to the point that the increase in their bond dissociation enthalpies may be as large as 240%. More importantly, the weaker the interaction, the larger the increase, so in some cases the linkage that stabilizes the most is the alkaline-earth bond, whereas in others is the hydrogen bond. In all cases, the formation of the MX2:XH:NH3 ternary complex is followed by a spontaneous proton transfer, very much as previously found for the Be-containing analogues. Similarly, MX2:FCl:NH3 complexes evolve from a chlorine-shared ternary complex (MX2FClNH3) or from an ion pair (MX2F-NH3Cl+) if M=Ca. Although F is the only halogen without sigma-hole, MgCl2 derivatives induce the appearance of a sigma-hole on it, though less deep than those induced by BeCl2. We have also studied whether Mg and Ca bond-containing complexes MR2:FY (R=H, F, Cl; Y=NH2, OH, F, Cl) may react to form radicals, as it has been found for the Be-containing analogues. These interactions provoke a drastic decrease in the F-Y bond dissociation enthalpy, very much as the one reported for the corresponding Be-analogues, to the point that in some cases the formation of the corresponding MR2F center dot+Y radicals becomes exothermic. Hence, the general conclusion of this study is that Mg or Ca derivatives give place to similar or even larger perturbations on the electron density than those induced by Be, a result not easily predictable.
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10. |
- Nerhagen, Lena, et al.
(författare)
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Cost-effective analysis of local policy measure to improve air quality in Stockholm : an exploratory study
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is a result of the research undertaken in the project TESS - Traffic Emissions, Socioeconomic valuation and Socioeconomic measures. In this report, we have studied the cost-effectiveness of particulate matter (PM) reductions from local emission sources in the Stockholm area. The input in the analysis is cost and effectiveness data collected from other studies and reports on reductions in emissions from traffic and residential heating. Contrary to other cost-effectiveness studies we have also included abatement measures where the effect is mainly due to adaptations in behavior. One example is congestion charging that we have assumed have a zero cost. We have also investigated the effect of different targeting strategies. Either the focus is on achieving air quality limit values for PM10 or the focus is on improvement in human health. In the first case we have assumed that the aim is to reduce emissions of PM10. In the second case the aim has been formulated as a reduction of the number of years of life lost (YOLL) in the population that would result if we reduce the concentrations of particulate matter in the city. The cost-effective analysis is done with a simple linear programming model. According to our results, congestion charging, a change to low-emission vehicles and installation of accumulator tanks are the least cost abatement measures irrespective of the target used in the analysis. For congestion charging and low-emission vehicles this is due to the assumption made that the abatement cost is zero. Thereafter however, the choice of measures depends on the choice of target. While less use of studded tires is efficient in order to reduce PM10 emissions, this is not a measure that has a large impact on the reduction of YOLL. This result relies on the assumptions made regarding the mortality impact of non-exhaust PM versus combustion PM.
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