| 1. |
- Gyllenberg, Mats, 1955-, et al.
(författare)
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Conditional reproductive strategies under variable environmental conditions
- 2017
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Ingår i: Annales Zoologici Fennici. - : Finnish Zoological and Botanical Publishing Board. - 0003-455X .- 1797-2450. ; 54:1-4, s. 193-204
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Tidskriftsartikel (refereegranskat)abstract
- Within the framework of adaptive dynamics we consider the evolution by natural selection of reproductive strategies in which individualsmay adjust their reproductive behaviour in response to changing environmental conditions. As a specific example we consider a discrete-time model in which possible fluctuations in the environmental conditions are caused by predator-prey interaction. Our main findings include: 1) Coexistence between two fixed strategies (i.e., strategies that do not adjust to changing environmental conditions) is impossible. There exists a best fixed strategy, which invades and ousts all other fixed strategies. 2) A necessary condition for conditional (adjustable) strategies to evolve is that there are fluctuations in the environmental conditions. Predator-prey interactions may cause such fluctuations and under natural assumptions there exists an optimal conditional strategy which is uninvadable and invades and ousts allother strategies.
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| 2. |
- Lindström, Torsten, 1965-
(författare)
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Investeringar blir till konsumption
- 2012
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Annan publikation (populärvet., debatt m.m.)abstract
- Att lära sig räkna övningsexempel i matematikmed digitala hjälpmedel saknar bildningsvärde och gör kunskapen teknikberoende. Kunskapen föråldras på det här viset fort.
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| 3. |
- Lindström, Torsten, 1965-
(författare)
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Monotone dynamics or not? : Dynamical consequences of various mechanisms for delayed logistic growth
- 2017
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Ingår i: Differential Equations & Applications. - : Element d.o.o.. - 1847-120X. ; 9:3, s. 379-382
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we interpret the global stability properties of the delayed single species chemostat in terms of monotone dynamics on an asymptotically invariant hyperplane in the state space. The consequence is a translation of advanced analysis and delay differential equations into sign checks and ordinary differential equations for an important single species model with explicit resource dynamics. Complete proofs are included, since the limiting behavior at asymptotically invariant sets may not agree with the limiting behavior of the original system even in the finite dimensional case (Thieme (1992)). A delayed logistic equation based on explicit resource dynamics falls out as a limiting case of the chemostat and we claim this to be a new mechanistic interpretation of delayed logistic models. We continue by comparing these results to several other delayed logistic models that has been mechanistically justified in the literature. We conclude that monotone dynamics apply in several cases. We improve one global stability result that cannot be obtained with by the use of monotone dynamics and end up by pointing out the dynamical differences between Hutchinson’s (1948) delayed logistic equation and those with mechanistic interpretations.
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| 4. |
- Lindström, Torsten, 1965-, et al.
(författare)
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On the stability-complexity relation for unsaturated semelpareous discrete food-chains
- 2011
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Ingår i: Studies in mathematical sciences. - 1923-8444 .- 1923-8452. ; 2:1, s. 157-182
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we formally prove that invading carnivores in thediscrete food-chain derived and preliminary analyzed inLindström (2002) always makes thesystem less stable and thus, limit the food-chain length in thecorresponding system. Hence, invading unsaturated carnivores arenot able to stabilize oscillatory dynamics.What we prove constitutes a significant difference betweendiscrete and continuous food-chains. Actually, Freedman andWaltman (1977) related the stabilizingproperties of an invading carnivore in continuous food-chains to absence of saturation: An unsaturated carnivore keeps at least oneinterior equilibrium - if one exists - locally stable.One consequence is that the dynamics of unsaturated discretefood-chains display similarities with saturated continuousfood-chains. Indeed, discrete dynamics seem to have a similardestabilizing impact on the dynamics as saturation has.
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| 5. |
- Lindström, Torsten, 1965-
(författare)
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Problems in relating various tasks and their samplesolutions to Bloom’s taxonomy
- 2017
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Ingår i: The Mathematics Enthusiast. - : University of Montana. - 1551-3440. ; 14:1-3, s. 15-28
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we analyze sample solutions of a number of problems and relate them to their level as prescribed by Bloom’s taxonomy. We relate these solutions to a number of other frameworks, too. Our key message is that it remains insufficient to analyze written forms of these tasks. We emphasize careful observations of how different students approach a solution before finally assessing the level of tasks used. We take the arithmetic series as our starting point and point out that the objective of the discussion of the examples here in no way is to indicate an optimal way towards a solution. Instead, our intent is to demonstrate the potential of well selected tasks and the variation that could be observed as students develop their solutions. A large part of this work is devoted to an analysis of the richness of the square triangular number problem.
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| 6. |
- Lindström, Torsten, 1965-
(författare)
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Skrivstilen som försvann
- 2013
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Annan publikation (populärvet., debatt m.m.)abstract
- Förmågan att ta anteckningar vid högre studier är något som måste tränas under skoltiden. Man måste lära sig skrivstil. Det ger ett aktivt förhållningssätt till studierna, till skillnad från att bara passivt lyssna på inspelade föreläsningar, skriver professor Torsten Lindström
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| 7. |
- Lindström, Torsten, 1965-
(författare)
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Torsås framtid en valfråga
- 2012
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Ingår i: Barometern OT. - Kalmar. - 1103-906X.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Få barnfamiljer väljer att flytta till orter där inte skola finns för mer än något år framåt. Om man stryper inflyttningen så finns snart inga skolor alls kvar där. Och vilken annan verksamhet kommer då att finns kvar?
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