Transaction cost influence on price hedging strategies : a study of farms with large-scale grain production

Agricultural businesses are exposed to many risk factors. For grain producers there are substantial risks which may affect income and costs. One way for producers to protect themselves is by hedging, which will help to stabilize income earnings. Futures- and forward contracts is one way for producers to do that. When establishing contracts, a lot of resources are needed and may lead to extended costs. The decision making is affected by uncertainty, trust, and relationship-specific investments. Purpose of study is to create an understanding for how contract writing costs may influence the attitude to forward- or futures contracts and implementation. In order to support this aim; a multiple case study of eight farms with large-scale grain production was conducted. Information was gathered through qualitative interviews. The study has identified that transaction costs vary between futures- and forward contracts. Variation stems from two factors, uncertainty of grain prices and the ability to create a relationship with another actor. Substantial time and resources are needed for an understanding of grain markets, therefore very few farmers use future contracts. Forward contracts benefit from the ability to create long-standing relationships with another actor. These relationships are beneficial as they save time and resources, thereby reducing the perceived transaction cost compared to futures contracts. Therefore, it is perceived that transaction cost do have an impact when choosing between the two options, and why forward contracts is the most frequently used hedging strategy.Lantbruksverksamheter utsätts för många riskfaktorer, vilka måste hanteras. Inom spannmålsodling finns betydande risker som kan påverka eventuella intäkter och utgifter. För att skydda sig mot riskerna och jämna ut intäkterna är prissäkring vid försäljning en möjlig strategi. Framförallt sker prissäkring genom att ett futures- eller forwardkontrakt tecknas. Skrivande av kontrakt kan dock medföra att en betydande mängd resurser och kostnader behövs spenderas via kontraktets upprättande. På grund av osäkerhet, förtroende eller relationsspecifika tillgångar kan de kostnader som uppstår variera mellan olika former av kontrakt, och därigenom påverka beslutet rörande vilket kontrakt som ska tecknas. Syftet med denna studie är att skapa en förståelse för hur kostnaderna vid kontraktsskrivande påverkar inställningen till futures- och forwardkontrakt, samt hur detta i sin tur påverkar valet av att implementera futures- eller forwardkontrakt som prissäkringstrategi. Genom en kvalitativ forskningsstrategi har en multipel fallstudie på 8 gårdar med storskalig spannmålsproduktion genomförts. Empiri har samlats in genom intervjuer för att ge en djupare förståelse till studiens syfte. Studien visar att transaktionskostnadernas upplevda storlek vid kontraktsskrivande skiljer sig mellan futures- och forwardkontrakt. Framförallt påverkas de olika kontrakten olika av den osäkerhet som finns om marknaden, samt vilket förtroende som en relation med en aktör kan betyda för transaktionskostnadernas storlek. På grund av att betydande resurser behövs spenderas för att förstå marknaden på futureskontrakt jämfört med forwardkontrakt påverkas inställningen negativt. Vid tecknande av forwardkontrakt kan dock ett ömsesidigt förtroende mellan de två kontraktsparterna minska transaktionskostnaderna, och således påverka inställningen positivt. Transaktionskostnadernas påverkan på inställningen är därför en bidragande faktor till att forwardkontrakt tillämpas i större utsträckning som prissäkringstrategi jämfört med futureskontrakt

Efficient structural symmetry breaking for constraint satisfaction problems

Symmetry breaking for constraint satisfaction problems (CSPs) has attracted considerable attention in recent years. Various general schemes have been proposed to eliminate symmetries. In general, these schemes may take exponential space or time to eliminate all the symmetries. We identify several classes of CSPs that encompass many practical problems and for which symmetry breaking for various forms of value and variable interchangeability is tractable using dedicated search procedures or symmetry-breaking constraints that allow nogoods and their symmetrically equivalent solutions to be stored and checked efficiently

Amelogenin, an extracellular matrix protein, in the treatment of venous leg ulcers and other hard-to-heal wounds: Experimental and clinical evidence

Amelogenins are extracellular matrix proteins that, under physiological conditions, self-assemble into globular aggregates up to micron-sizes. Studies with periodontal fibroblasts indicate that attachment to these structures increases the endogenous secretion of multiple growth factors and cell proliferation. Pre-clinical and clinical studies indicate that cutaneous wounds benefit from treatment with amelogenins. A randomized controlled trial (RCT) involving patients with hard-to-heal venous leg ulcers (VLUs) (ie, ulcers with a surface area ≥10 cm2 and duration of ≥6 months) showed that the application of amelogenin (Xelma®, Molnlycke Health Care, Gothenburg, Sweden) as an adjunct treatment to compression results in significant reduction in ulcer size, improvement in the state of ulcers, reduced pain, and a larger proportion of ulcers with low levels of exudate, compared with treatment with compression alone. Amelogenin therapy was also shown to be safe to use in that there were no significant differences in adverse events noted between patients treated with amelogenin plus compression and those treated with compression alone. Case study evaluations indicate that the benefits of amelogenin therapy demonstrated in the RCT are being repeated in “real life” situations and that amelogenin therapy may also have a role to play in the treatment of other wound types such as diabetic foot ulcers

The Effect of a Synthetic Heparan Sulfate on the Healing of Colonic Anastomoses

Background. The mimetic compound OTR4120 may replace endogenous-degraded heparan sulfates that normally maintain the bioactivity of growth factors that are important for tissue repair. Herein, we investigated the effect of OTR4120 on the healing of normal colonic anastomoses. Methods. We evaluated the following two treatment groups of male Sprague Dawley rats (220–256 g): control-treated colonic anastomoses (n=25) and OTR4120-treated colonic anastomoses (n=25). We resected 10 mm of the left colon and then applied either saline alone (control) or OTR4120 (100 μg/mL) in saline to the colonic ends before an end-to-end single-layer anastomosis was constructed and again on the anastomosis before the abdomen and skin were closed. Results. On postoperative day 3, the anastomotic breaking strengths were 1.47 ± 0.32 N (mean ± SD) in the control group and 1.52 ± 0.27 N in the OTR4120-treated animals (P=0.622). We also found that the hydroxyproline concentration (indicator of collagen) in the anastomotic wounds did not differ (P=0.571) between the two groups. Conclusions. Our data demonstrate that a single local application of OTR4120 intraoperatively did not increase the biomechanical strength of colonic anastomoses at the critical postoperative day 3 when the anastomoses are the weakest

The Effect of a Synthetic Heparan Sulfate on the Healing of Colonic Anastomoses

Background. The mimetic compound OTR4120 may replace endogenous-degraded heparan sulfates that normally maintain the bioactivity of growth factors that are important for tissue repair. Herein, we investigated the effect of OTR4120 on the healing of normal colonic anastomoses. Methods. We evaluated the following two treatment groups of male Sprague Dawley rats (220-256 g): control-treated colonic anastomoses (n = 25) and OTR4120-treated colonic anastomoses (n = 25). We resected 10 mm of the left colon and then applied either saline alone (control) or OTR4120 (100 μg/mL) in saline to the colonic ends before an end-to-end single-layer anastomosis was constructed and again on the anastomosis before the abdomen and skin were closed. Results. On postoperative day 3, the anastomotic breaking strengths were 1.47 ± 0.32 N (mean ± SD) in the control group and 1.52 ± 0.27 N in the OTR4120-treated animals (P = 0 622). We also found that the hydroxyproline concentration (indicator of collagen) in the anastomotic wounds did not differ (P = 0 571) between the two groups. Conclusions. Our data demonstrate that a single local application of OTR4120 intraoperatively did not increase the biomechanical strength of colonic anastomoses at the critical postoperative day 3 when the anastomoses are the weakest

Catchment characteristics control boreal mire nutrient regime and vegetation patterns over ~5000 years of landscape development

Vegetation holds the key to many properties that make natural mires unique, such as surface microtopography, high biodiversity values, effective carbon sequestration and regulation of water and nutrient fluxes across the landscape. Despite this, landscape controls behind mire vegetation patterns have previously been poorly described at large spatial scales, which limits the understanding of basic drivers underpinning mire ecosystem services. We studied catchment controls on mire nutrient regimes and vegetation patterns using a geographically constrained natural mire chronosequence along the isostatically rising coastline in Northern Sweden. By comparing mires of different ages, we can partition vegetation patterns caused by long-term mire succession

The scale of population structure in Arabidopsis thaliana

The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales

Tracing and Explaining the Execution of CLP(FD) Programs in SICStus Prolog

The increasing interest in Constraint Programming (CP) we now witness gives rise to a demand for new and improved debugging techniques. Graphical tools, such as constraint- and search-tree visualizers, seem to be appropriate to get a general understanding of the complex process of constraint solving. However, many such tools have been built in an ad hoc way, forcing the developer to, for each new tool, provide relevant information from the constraint solver. In this thesis, we present a solution to the problem, limiting ourselves to Constraint Logic Programming over Finite Domains (\clpfd). In order to do this, we come up with a trace structure for describing the execution of \clpfd\ programs in detail. The trace structure consists of various trace events, each trace event containing different information depending on when in the solving process it is created. Among other things, the trace structure contains information about constraint posting, constraint awakening and domain narrowing. We also incorporate explanations in the trace structure, i.e.\ reasons for why certain solver actions occur. Furthermore, we come up with a format for describing the execution of the filtering algorithms of global constraints. An implementation of the trace structure in \sicstus\ Prolog is also presented, as well as a tool using the trace; an extension to the ordinary Prolog debugger

Set Constraints for Local Search

Combinatorial problems are ubiquitous in our society and solving such problems efficiently is often crucial. One technique for solving combinatorial problems is constraint-based local search. Its compositional nature together with its efficiency on large problem instances have made this technique particularly attractive. In this thesis we contribute to simplifying the solving of combinatorial problems using constraint-based local search. To provide higher-level modelling options, we introduce set variables and set constraints in local search by extending relevant local search concepts. We also propose a general scheme to follow in order to define what we call natural and balanced constraint measures, and accordingly define such measures for over a dozen set constraints. However, defining such measures for a new constraint is time-consuming and error-prone. To relieve the user from this, we provide generic measures for any set constraint modelled in monadic existential second-order logic. We also theoretically relate these measures to our proposed general scheme, and discuss implementation issues such as incremental algorithms and their worst-case complexities. To enable higher-level search algorithms, we introduce constraint-directed neighbourhoods in local search by proposing new constraint primitives for representing such neighbourhoods. Based on a constraint, possibly modelled in monadic existential second-order logic, these primitives return neighbourhoods with moves that are known in advance to achieve a decrease (or preservation, or increase) of the constraint measures, without the need to iterate over any other moves. We also present a framework for constraint-based local search where one can model and solve combinatorial problems with set variables and set constraints, use any set constraint modelled in monadic existential second-order logic, as well as use constraint-directed neighbourhoods. Experimental results on three real-life problems show the usefulness in practice of our theoretical results: our running times are comparable to the current state-of-the-art approaches to solving the considered problems