Selfdual strings and loop space Nahm equations

We give two independent arguments why the classical membrane fields should be loops. The first argument comes from how we may construct selfdual strings in the M5 brane from a loop space version of the Nahm equations. The second argument is that there appears to be no infinite set of finite-dimensional Lie algebras (such as $su(N)$ for any $N$) that satisfies the algebraic structure of the membrane theory.Comment: 28 pages, various additional comment

Abelian M5-brane on S6S^6

We study the abelian M5 brane on $S^6$. From the spectrum we extract a series expansion for the heat kernel. In particular we determine the normalization for the coefficient $a$ in the M5 brane conformal anomaly. When we compare our result with what one gets by computing the Hadamard-Minakshisundaram-DeWitt-Seeley coefficients from local curvature invariants on $S^6$, we first find a mismatch of one unit. This mismatch is due to an overcounting of one zero mode. After subtracting this contribution, we finally find agreement. We perform dimensional reduction along a singular circle fiber to five dimensions where we find the conformal anomaly vanishes.Comment: 40 page

Grassland plant diversity in relation to historical and current land use

About 150 years ago agriculture was drastically reformed and around 90% of the formerly vastly distributed semi-natural grasslands, i.e. unfertilised and uncultivated grasslands, have since then disappeared. Accordingly, grassland plant diversity has declined due to abandonment, changed management methods and habitat loss. Grasslands are species rich as a result of a long management history; the management providing niches for a variety of organisms. Current diversity patterns are thus a result of historical and current land use in combination. This thesis explores some of the connections between historical land use and grassland vascular plants. Two studies concerns the habitat level, i.e. local conditions for grassland plants, two studies the landscape level, i.e. habitat patches in relation to neighbouring patches. In the first study, grassland plant diversity was found to be strongly correlated to 18th and 19th century land use, more so than to current land use. Furthermore, the particular sequence by which one land use changed into another from the 18th century until the mid 20th century was an important predictor of plant diversity. In the second study, detailed comparison of 18th century and current grassland management revealed that current grassland management lacks several ecological factors that the literature deems important for grassland plant reproduction. The third and the fourth study explore how plant species richness in specific grasslands is related to the surrounding landscape by studying how current, 19th and 20th century grassland connectivity and area are reflected in current species richness of grassland plants. They revealed that the response of grassland plant diversity to different fragmentation components can differ widely between two superficially similar landscapes, although historical components were important in both landscapes for explaining current diversity patterns. Moreover, the direction of livestock movement within the pre-industrial landscape appears to have been an important determinant regarding the functional connectivity between different grassland patches. Given the strong correlation between historical agricultural practices and current plant diversity patterns, this thesis discusses this diversity as a biocultural heritage. The historical aspects of grassland diversity ought to be taken into account in conservation and restoration measures

PhytoMilk

Potential improvement of the salutary effect of organic dairy milk by forage species and by supplementation

A short representation of the six-dimensional (2, 0) algebra

We construct a BPS-saturated representation of the six-dimensional (2, 0) algebra with a certain non-zero value of the `central' charge. This representation is naturally carried by strings with internal degrees of freedom rather than by point particles. Upon compactification on a circle, it reduces to a massive vector multiplet in five dimensions. We also construct quantum fields out of the creation and annihilation operators of the states of this representation, and show how they give rise to a conserved two-form current that can be coupled to a tensor multiplet. We hope that these results may be relevant for understanding the degrees of freedom associated with strings in interacting (2, 0) theories.Comment: 11 page

The Effect of Uncertainty in Regulatory Delay on the Rate of Innovation

Earlier studies examining house pricing have mainly focused on the secondary market and have often overlooked the primary market and newly produced housing units. This paper studies the pricing strategies in the primary housing market, as that segment differs from the secondary market. By using data from one newly produced housing project, we are able to exclude a number of project-specific factors, as they are nearly identical for all observations. This allows us to focus on factors that are directly observable and require very little assessment or evaluation in our estimations of list prices, selling prices and selling times. The empirical results exhibit a close relationship between list- and selling prices, but a few factors differ significantly between the two. Such differences could indicate a misinterpretation of the market by the seller. The time-on-market model shows that a number of factors affect selling times as well. The results indicate a relationship between "mispriced" factors and their impact on the selling times, where "over-priced" factors seem to prolong the time-on-market and "under-priced" factors seem to shorten the time-on-market. By dividing the units into different price ranges, it becomes clear that high-priced housing is more difficult to price and take longer to sell. This relationship is strengthened by a degree-of-overpricing variable, which exhibits a positive sign in the time-on-market model. The effect is the strongest in low-priced units and not significant for higher-priced units. Other factors that affect pricing strategies require a broader discussion. Analogies from similar consumer good markets indicate that pricing strategies are dependent on the types of customers in the target groups as well as the stage in the project life-cycle

Low energy dynamics of self-dual A_1 strings

We examine the interrelation between the (2,0) supersymmetric six dimensional effective action for the A_1 theory, and the corresponding low-energy theory for the collective coordinates associated to supersymmetric selfdual BPS strings. We argue that this low-energy theory is a two-dimensional N = 4 supersymmetric sigma model.Comment: 8 pages. The ansatz for the fermionic collective coordinates has been slightly modified, and a discussion of its validity has been included. The curvature term has been corrected. To be published in Nuclear Physics

Loop space, (2,0) theory, and solitonic strings

We present an interacting action that lives in loop space, and we argue that this is a generalization of the theory for a free tensor multiplet. From this action we derive the Bogomolnyi equation corresponding to solitonic strings. Using the Hopf map, we find a correspondence between BPS strings and BPS monopoles in four-dimensional super Yang-Mills theory. This enable us to find explicit BPS saturated solitonic string solutions.Comment: 29 pages, v3: section 5 is rewritten and string solutions are found, v4: a new section on general covariance in loop spac