BPS surface observables in six-dimensional (2,0) theory

The supergroup OSp(8*|4), which is the superconformal group of (2,0) theory in six dimensions, is broken to the subgroup OSp(4|2)xOSp(4|2) by demanding the invariance of a certain product in a superspace with eight bosonic and four fermionic dimensions. We show that this is consistent with the symmetry breaking induced by the presence of a flat two-dimensional BPS surface in the usual (2,0) superspace, which has six bosonic and sixteen fermionic dimensions.Comment: 9 pages, LaTeX. v2: reference adde

Superconformal symmetry in the interacting theory of (2,0) tensor multiplets and self-dual strings

We investigate the concept of superconformal symmetry in six dimensions, applied to the interacting theory of (2,0) tensor multiplets and self-dual strings. The action of a superconformal transformation on the superspace coordinates is found, both from a six-dimensional perspective and by using a superspace with eight bosonic and four fermionic dimensions. The transformation laws for all fields in the theory are derived, as well as general expressions for the transformation of on-shell superfields. Superconformal invariance is shown for the interaction of a self-dual string with a background consisting of on-shell tensor multiplet fields, and we also find an interesting relationship between the requirements of superconformal invariance and those of a local fermionic kappa-symmetry. Finally, we try to construct a superspace analogue of the Poincare dual to the string world-sheet and consider its properties under superconformal transformations.Comment: 31 pages, LaTeX. v2: clarifications and minor correction

Manifest superconformal covariance in six-dimensional (2,0) theory

A superconformal generalization of Dirac's formalism for manifest conformal covariance is presented and applied to the free (2,0) tensor multiplet field theory in six dimensions. A graded symmetric superfield, defined on a supercone in a higher-dimensional superspace is introduced. This superfield transforms linearly under the transformations of the supergroup OSp(8*|4), which is the superconformal group of the six-dimensional (2,0) theory. We find the relationship between the new superfield and the conventional (2,0) superfields in six dimensions and show that the implied superconformal transformation laws are correct. Finally, we present a manifestly conformally covariant constraint on the supercone, which reduces to the ordinary differential constraint for the superfields in the six-dimensional space-time.Comment: 12 pages, LaTeX. v2: minor clarification adde

Supersymmetric coupling of a self-dual string to a (2,0) tensor multiplet background

We construct an interaction between a (2,0) tensor multiplet in six dimensions and a self-dual string. The interaction is a sum of a Nambu-Goto term, with the tension of the string given by the modulus of the scalar fields of the tensor multiplet, and a non-local Wess-Zumino term, that encodes the electromagnetic coupling of the string to the two-form gauge field of the tensor multiplet. The interaction is invariant under global (2,0) supersymmetry, modulo the equations of motion of a free tensor multiplet. It is also invariant under a local fermionic kappa-symmetry, as required by the BPS-property of the string.Comment: 12 pages, LaTe

Effects of Forest Ditch Cleaning on Surface Water Quality

Ditch cleaning (DC) is recommended by authorities to Swedish landowners to maintain forest productivity after forest harvest by lowering groundwater tables of catchment soils. Knowledge regarding the impact of this practice on surface water quality is limited, and results from previous research vary. Therefore, this master thesis aims to contribute to the knowledge gap by evaluating the impact of DC in relation to the impact of clear-cutting (CC) on ditch water quality. Additionally, I attempt to investigate whether impacts of DC on water quality can be predicted from catchment characteristics. The study was based on synoptic sampling of water chemistry conducted according to a paired design with 25 cleaned and 25 uncleaned reference ditches located along the east coast of mid-Sweden. The sites were further selected to investigate effects of CC forest harvest, with 25 sites located in direct connection to CC areas and 25 sites located in forested areas (unpaired). Sampling was conducted at three different occasions for 25 chemical variables including standard water chemistry, mercury and dissolved greenhouse gases. The results showed that six out of the 25 chemical variables analysed were significantly different between DC and reference (R) sites, namely pH, sulphate (SO4), SUVA254, carbon dioxide (CO2-C), methane (CH4-C), and nitrous dioxide (N2O-N). A lowered groundwater table and more deeper flow paths following DC is suggested as the main cause for the obsereved differences in chemical composition. In contrast, following CC higher concentrations of many chemical variables could be linked to more superficial groundwater flow with many of the variables typically linked to organic matter and nutrients. No interaction effect was observed between treatments, meaning that DC does not enhance the impact of CC. However, CO2-C was significantly lower in DC compared to R, but significantly higher in CC compared to F, indicating that DC counteracts CC in some respects. Finally, the predictability of water quality following DC based on catchment characteristics proved weak. Only ΔSO4 and ΔCO2-C models showed predictive relevance, but the low explanatory power of the models suggest that these models should be used with caution and seen as indications rather than used for predictions. The results of this thesis provide important information on how water quality could be affected by DC. The multi-variable inclusion of the current study is an important knowledge basis that can be used as a starting point for more in-depth evaluations of the effects of DC on different water quality aspects

Health predicting factors in a general population over an eight-year period in subjects with and without chronic musculoskeletal pain

<p>Abstract</p> <p>Background</p> <p>Many factors are proposed to be associated with health-related quality of life. Knowledge of health factors associated to development of a good health-related quality of life could be of use in clinical practice and public health work. The aim of this study was to investigate the associations between suggested health factors and health-related quality of life at baseline and in an eight-year follow up in subjects with and without chronic musculoskeletal pain in a cohort from a general population.</p> <p>Methods</p> <p>The study was designed as a longitudinal study in a Swedish general population (N = 1 849) with a postal questionnaire at baseline 1995 and at follow up 2003. Subjects were divided into two groups, according to their response about chronic musculoskeletal pain at baseline. Health-related quality of life was assessed by the SF-36 together with suggested health factors. The associations between SF-36 subscales and suggested health factors were estimated by OR and 95% CI calculated by multivariable logistic regressions, with adjustment for all health factors, age, sex and baseline SF-36 values.</p> <p>Results</p> <p>Although subjects without chronic musculoskeletal pain reported better health-related quality of life than subjects with chronic pain, similar health factors were found to be associated to higher scores in SF-36 at baseline and predicted a better outcome in the eight-year follow up. The most consistent finding was a better health outcome in the eight-year follow up for subjects that were feeling rested after sleep. Other factors that in some aspects predicted a better outcome were belonging to higher socioeconomic group, being a native Swede, having emotional support, having good sleep structure, never being or being a former smoker, and regularly drinking alcohol.</p> <p>Conclusion</p> <p>The most important health factor in subjects with and without chronic musculoskeletal pain was feeling rested after sleep, but also emotional support, sleep structure, smoking and alcoholic habits appears to be important components. These health factors could be important to address in clinical work with painful musculoskeletal disorders. Since several health factors are common in both subjects with and without pain there could be a common strategy to be formed in public health programmes.</p