Pricing of American Options

This thesis investigates the free boundary value problem of pricing American put options written on one underlying asset. In particular, attention is given to nd an accurate approximation of the critical ex- ercise boundary. The problem is approached using radial basis func- tions in the shape of Gaussian densities, and basis functions in the form of European put options. Furthermore, the domain is extended into the strike direction. Prices are computed for a range of strikes and maturities, and the critical strike prices are retrieved. Finally, the Merton Jump Diusion model is considered generating a partial integro dierential equation. Using Gaussian densities, prices and boundaries are computed on the extended domain

Streptomyces alleviate abiotic stress in plant by producing pteridic acids

Soil microbiota can confer fitness advantages to plants and increase crop resilience to drought and other abiotic stressors. However, there is little evidence on the mechanisms correlating a microbial trait with plant abiotic stress tolerance. Here, we report that Streptomyces effectively alleviate drought and salinity stress by producing spiroketal polyketide pteridic acid H (1) and its isomer F (2), both of which promote root growth in Arabidopsis at a concentration of 1.3 nM under abiotic stress. Transcriptomics profiles show increased expression of multiple stress responsive genes in Arabidopsis seedlings after pteridic acids treatment. We confirm in vivo a bifunctional biosynthetic gene cluster for pteridic acids and antimicrobial elaiophylin production. We propose it is mainly disseminated by vertical transmission and is geographically distributed in various environments. This discovery reveals a perspective for understanding plant-Streptomyces interactions and provides a promising approach for utilising beneficial Streptomyces and their secondary metabolites in agriculture to mitigate the detrimental effects of climate change

Potato trait development going fast-forward with genome editing

Implementations and improvements of genome editing techniques used in plant science have increased exponentially. For some crops, such as potato, the use of transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR) has moved to the next step of trait development and field trials, and should soon be applied to commercial cultivation

Potato trait development going fast-forward with genome editing

Implementations and improvements of genome editing techniques used in plant science have increased exponentially. For some crops, such as potato, the use of transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR) has moved to the next step of trait development and field trials, and should soon be applied to commercial cultivation

Biological control of strawberry diseases by Aureobasidium pullulans and sugar beet extract under field conditions

Grey mould (caused by Botrytis cinerea) is the most important pathogen underlying high fungicide dependence in strawberry fields. Reliable biocontrol agents (BCAs) with improved efficiency are needed to replace fungicides. The yeast-like beneficial fungus Aureobasidium pullulans (AP-SLU6) has previously exhibited great potential to combat grey mould in greenhouse environments. Here we report results from a two-year full-factorial field trial in a conventional strawberry field, in which we tested two different concentrations of A. pullulans (10(7) CFU/ml and 10(6) CFU/ml) and sugar beet extract (SBE). The results showed that all the field treatments reduced grey mould severity postharvest and increased shelf life of the harvested fruit in both years. The best effect was achieved using the highest conidial concentration of A. pullulans, which also resulted in 53% higher fruit production compared to the control treatment at the end of the season, indicating a plant-growth promoting effect of the BCA. These results reveal that spray applications of these novel BCAs contribute to reliable biocontrol of grey mould, leading to improvement of the shelf life of strawberry sales boxes. These findings suggest that A. pullulans and SBE can contribute to a shift from chemical fungicides to sustainable methods without compromising cropping security

Professional Bureaucracy and Health Care Managers’ Planned Change Strategies: Governance in Swedish Health Care

To increase efficiency and quality, process development has been implemented in many Swedish hospitals. These hospitals are usually organized as professional bureaucracies in which health care managers have limited decision control. The new governance principles has been implemented without removing bureaucratic elements. This study analyzes how managers implement planned change in these professional bureaucracies, considering if managers coaching style, organizational preconditions, implementation strategy, appraisal of change and clinic autonomy, is associated with health care process quality (HPQ). The study is based on interviews with health care managers and longitudinal assessments of HPQ. The results revealed significant differences between coaching style, organizational preconditions, and HPQ over time. The conclusion is that leadership and preconditions is of importance for the health care manager’s ability to work with planned change, as that the health care managers understand how management methods, governance principles, and professional bureaucracies work in practice

Tissue Culture and Refreshment Techniques for Improvement of Transformation in Local Tetraploid and Diploid Potato with Late Blight Resistance as an Example

Potato (Solanum tuberosum) is among the best producers of edible biomass in terms of yield per hectare and a variety of different regional cultivars are used as a staple commodity inmany countries. However, this crop is attacked by several diseases, with the worst being the late blight disease caused by Phytophthora infestans. Stacking of resistance (R) genes from wild Solanum relatives are interesting prospects for the sustainable control of late blight. Therefore, we optimized methods for the efficient generation and screening of R-gene-containing transformants in tetraploidand diploid hybrid potato genotypes. Using these methods, a high transformation efficiency was achieved for the transformation of tetraploid and diploid potato lines with a triple resistance (3R)gene construct. Transformation efficiencies were improved by optimizing several factors affecting regeneration, including the quality of the starting plant material, and the composition of the plant growth regulators used during selective regeneration. A refreshment protocol was designed to alleviatein vitro related stress in stock plants, which significantly improved the growth vigor and resulted in a 4- to 10-fold increase in transformation efficiency. Furthermore, long-term exposure to exogenous Indole-3-butyric acid that is usually used for the initiation of rootsin vitro, was found to cause aberrant morphological phenotypes in potato

Linking crop traits to transcriptome differences in a progeny population of tetraploid potato

Background Potato is the third most consumed crop in the world. Breeding for traits such as yield, product quality and pathogen resistance are main priorities. Identifying molecular signatures of these and other important traits is important in future breeding efforts. In this study, a progeny population from a cross between a breeding line, SW93-1015, and a cultivar, Desiree, was studied by trait analysis and RNA-seq in order to develop understanding of segregating traits at the molecular level and identify transcripts with expressional correlation to these traits. Transcript markers with predictive value for field performance applicable under controlled environments would be of great value for plant breeding. Results A total of 34 progeny lines from SW93-1015 and Desiree were phenotyped for 17 different traits in a field in Nordic climate conditions and controlled climate settings. A master transcriptome was constructed with all 34 progeny lines and the parents through a de novo assembly of RNA-seq reads. Gene expression data obtained in a controlled environment from the 34 lines was correlated to traits by different similarity indices, including Pearson and Spearman, as well as DUO, which calculates the co-occurrence between high and low values for gene expression and trait. Our study linked transcripts to traits such as yield, growth rate, high laying tubers, late and tuber blight, tuber greening and early flowering. We found several transcripts associated to late blight resistance and transcripts encoding receptors were associated to Dickeya solani susceptibility. Transcript levels of a UBX-domain protein was negatively associated to yield and a GLABRA2 expression modulator was negatively associated to growth rate. Conclusion In our study, we identify 100's of transcripts, putatively linked based on expression with 17 traits of potato, representing both well-known and novel associations. This approach can be used to link the transcriptome to traits. We explore the possibility of associating the level of transcript expression from controlled, optimal environments to traits in a progeny population with different methods introducing the application of DUO for the first time on transcriptome data. We verify the expression pattern for five of the putative transcript markers in another progeny population

Overview and breeding strategies of table potato production in Sweden and the Fennoscandian region

Recent reductions in the public commitment to potato breeding in Sweden, Norway and Finland call for an evaluation of the current situation regarding the commercial basis for, and structure of, potato breeding in these countries. We here review the extent of cultivation, processing and consumption of table potato in Sweden, as well as provide an overview of the potato breeding tools and programmes in the three countries. We then discuss various strategies to provide long-term stability and increase the impact of public potato breeding, based on the similar overall conditions for potato cultivation across the Fennoscandian region. The conclusions are twofold; first, an increased long-term funding of the public potato breeding programmes is necessary to maintain a minimum level of material, and second, a coordination of the breeding activities in the Fennoscandian region would be of great benefit to all involved stakeholders and allow an enhancement of the current national breeding programmes. In addition, we propose a minimum first field year population size for potato breeding

A fast, nondestructive method for the detection of disease-related lesions and wounded leaves

Trypan blue staining is a classic way of visualizing leaf disease and wound responses in plants, but it involves working with toxic chemicals and is time-consuming (2-3 days). Here, the investigators established near-infrared scanning with standard lab equipment as a fast and nondestructive method for the analysis of leaf injuries compared with trypan blue staining. Pathogen-inoculated and wounded leaves from potato, tomato, spinach, strawberry, and arabidopsis plants were used for proof of concept. The results showed that this newly developed protocol with near-infrared scanning gave the same results as trypan blue staining. Furthermore, a macro in FIJI was made to quantify the leaf damage. The new protocol was time-efficient, nondestructive, chemical-free and may be used for high-throughput studies