Combining astrometric and radial velocity data for exoplanet detection

Context: The Gaia satellite will be provide astrometry with micro-arcsecond accuracy. This will allow for the determination of the orbital elements of exoplanets with measurable astrometric signature. Astrometry alone is not be able to disentangle an ambiguity in the orientation of planetary orbits, just as radial velocity is only able to give the mass of orbiting planets combined with multiplicative factor. Combining astrometry and radial velocity this can be resolved. Many different approaches exist of how to parameterize and solve the problem of finding the orbital parameters. This text takes a look at one parametrization and one method for solving the problem. Aim: Define a model for the parametrization of the problem of finding the orbital elements for an exoplanet. This model should both describe the astrometric and radial velocity. Implement the model in AGISLab and determine how well it is able to retrieve the orbital elements. Method: The problem was parameterized using Thiele-Innes parameters for describing the orientation and semi-major axis of the system. Further parameters were; mass ratio of the planet to the star, time of periapsis passage, eccentricity of the orbit and period. In addition, the astrometric parameters were also included; position, parallax and proper motion. Radial motion was not included. The Levenberg-Marquardt algorithm was used for the optimization. Boundaries on the planetary parameters were introduced, in order to prevent unrealistic solutions, through transformations. The transformation of the parameters was a standard trigonometric function. To estimate the formal errors on the optimized parameters, parametric bootstrapping was performed. Result: The optimization works and provides sensible parameters, though the solution is very sensitive to the initial selection of parameters. Singular value decomposition of the matrix J|WJ, the Hessian of the merit function, indicates that the problem is ill-conditioned so bootstrapping may be a better solution for computing formal errors on the parameters than calculating them from the square root of the diagonal elements of its inverse. Bootstrapping also indicates that the formal errors of the parameters are not normally distributed. Conclusion: The method does work and allows for very easy combination of radial velocity and astrometric data. Due to the choice of parametrization and/or optimization procedure the method is unstable.I höst kommer rymdobservatoriet Gaia att sändas upp. Ett av dess mål är att mätapositionen av stjärnor med väldigt hög noggrannhet, denna positionsbestämning kallas astrometri. Gaias noggrannhet är såpass bra att det kommer bli möjligt att även mäta hur planeter när de färdas i sina banor runt stjärnor påverkar positionen av stjärnan. Astrometri kan inte ge en fullständig bild av hur planeten rör sig runt stjärnan utan kan endast se en projektion, En annan metod för planetdetektion är radiell hastighet. Detta går ut på att man mäter hur snabbt en stjärna rör sig bort eller emot oss på grund av en planet i om- loppsbana. Denna metod kan inte heller ge en fullständig bild av hur planeten rör sig. Genom att kombinera astrometri och radiell hastighet är det möjligt att ge en fullständig beskrivning av deras bana. Här presenteras en metod att kombinera radiell hastighet och astrometri genom att utnyttja att några av parametrarna är desamma för de två tillvägagångssätten. Dessvärre visar det sig att denna metod lider av några brister vilket gör att även om en beskrivning av planetbanan hittas är den väldigt osäker

Europeisk arrestordre - et nytt system for utlevering av lovbrytere?

Tema for avhandlingen er utlevering av lovbrytere, med særlig fokus på rammebeslutningen om europeisk arrestordre og Norges tilslutning til ordningen som etableres der

Can planetary instability explain the Kepler dichotomy?

The planet candidates discovered by the Kepler mission provide a rich sample to constrain the architectures and relative inclinations of planetary systems within approximately 0.5 AU of their host stars. We use the triple-transit systems from the Kepler 16-months data as templates for physical triple-planet systems and perform synthetic transit observations. We find that all the Kepler triple-transit and double-transit systems can be produced from the triple-planet templates, given a low mutual inclination of around five degrees. Our analysis shows that the Kepler data contains a population of planets larger than four Earth radii in single-transit systems that can not arise from the triple-planet templates. We explore the hypothesis that high-mass counterparts of the triple-transit systems underwent dynamical instability to produce a population of massive double-planet systems of moderately high mutual inclination. We perform N-body simulations of mass-boosted triple-planet systems and observe how the systems heat up and lose planets, most frequently by planet-planet collisions, yielding transits in agreement with the large planets in the Kepler single-transit systems. The resulting population of massive double-planet systems can nevertheless not explain the additional excess of low-mass planets among the observed single-transit systems and the lack of gas-giant planets in double-transit and triple-transit systems. Planetary instability of systems of triple gas-giant planets can be behind part of the dichotomy between systems hosting one or more small planets and those hosting a single giant planet. The main part of the dichotomy, however, is more likely to have arisen already during planet formation when the formation, migration or scattering of a massive planet, triggered above a threshold metallicity, suppressed the formation of other planets in sub-AU orbits.Comment: Accepted for publication in Ap

Bruk av individuell plan i habilitering av barn med cochleaimplantat : en kartlegging av foreldres erfaringer

Bakgrunn for egen undersøkelse og formålet med oppgaven: Forskning viser at barn som får cochleaimplantat har behov for langvarig og tverrfaglig habilitering for å få maksimalt utbytte av sine implantater. Samtidig blir behovet for en helhetlig og koordinert tankegang innen (re)habilitering fremhevet i flere offentlige dokumenter. Som et ledd i å møte dette behovet har man forsøkt å innføre individuell plan for personer med behov for langvarige og koordinerte tjenester. Barn med cochleaimplantat faller inn under denne målgruppen på grunn av deres omfattende habiliteringsbehov. Den empiriske delen av denne oppgaven er knyttet til prosjektet ”Talespråklig habilitering av døve og sterkt tunghørte barn fra 0-6 år som anvender cochleaimplantat”. Som følge av en henstilling fra Helsedirektoratet har samtlige av foreldrene til barna i dette prosjektet blitt introdusert for muligheten til å få opprettet en individuell plan. Selv om foreldrene synes å være positive til ordningen ved informasjonstidspunktet, ser det imidlertid ut til at det er få som har fått utarbeidet en slik plan. Min undersøkelse er organisert som en delundersøkelse til dette prosjektet, og jeg har i den forbindelse fått mulighet til å kontakte foreldrene til barna som deltar i prosjektet. Formålet med undersøkelsen er primært å kartlegge hvilke erfaringer foreldre til barn med cochleaimplantat har med individuell plan. Jeg vil imidlertid også søke å finne ut om man ut i fra foreldrenes svar kan antyde noen årsaker til at individuell plan ser ut til å være lite utbredt blant barn med cochleaimplantat. Problemstilling Hovedproblemstilling: ”Hvilke erfaringer har foreldre til barn med cochleaimplantat med ordningen med individuell plan?” Underproblemstillinger: •Har foreldrene hørt om ordningen med individuell plan? •Hvor mange av barna har en individuell plan? •Hva kan det skyldes at så få har en individuell plan? •Hvordan fungerer den individuelle planen hos de barna som har en slik? Metode og materiale: Undersøkelsen har en hovedsakelig kvantitativ tilnærming. Det er benyttet et surveydesign med strukturerte telefonintervjuer som instrument. I tilegg til de kvantitative dataene fra undersøkelsen, inneholder også datamaterialet noe kvalitative data. Disse dataene er benyttet for å supplere det kvantitative datamaterialet. Det totale datamaterialet fra undersøkelsen er sammenlignet med teori og tidligere forskning på området. Undersøkelsen omfatter intervjuer med 21 foreldre som har barn med cochleaimplantat. Resultater: Undersøkelsen viste at foreldrenes erfaringer med individuell plan var nokså varierende. De aller fleste foreldrene (18 av 21) hadde hørt om ordningen med individuell plan. Det varierte imidlertid hvem som hadde informert foreldrene og hva de hadde fått av informasjon. Til tross for at de aller fleste foreldrene kjente til ordningen, var det likevel relativt få barn som hadde en individuell plan. Kun 5 av de 21 foreldrene oppga at deres barn hadde en individuell plan. I tillegg til disse fem var det ytterligere to barn som hadde en individuell plan under utarbeidelse. Hva denne lave forekomsten skyldes, er det vanskelig å gi noe klart svar på. Foreldrenes svar antyder imidlertid manglende kjennskap til og ønske om individuell plan hos foreldrene, i tillegg til usikkerhet om ordningen og manglende initiativ blant tjenesteytere som mulige forklaringer. Ut i fra resultatene fra min undersøkelse er det vanskelig å påvise noen entydige tendenser til hvordan planen fungerer hos de barna som har en slik. Foreldrene gir ulike svar, og svarene deres kan tenkes å ha mange ulike forklaringer. Totalt sett ser det likevel ikke ut til at planen har ført til store endringer for de fleste av familiene i utvalget, verken når det gjelder samarbeid, koordinering, tjenestetilbud eller brukermedvirkning. Det ser imidlertid ut til at de som har en individuell plan i utvalget også var fornøyde med habiliteringstilbudet før de fikk en individuell plan. Dette kan være en medvirkende årsak til at jeg ikke har kunnet påvise store endringer som følge av innføringen av individuell plan. Resultatene fra denne undersøkelsen samsvarer i relativt stor grad med tidligere utført forskning om individuell plan

Flexible adaptation in Himalayan small-scale farming : Subsistence production, gender relations, and adaptive capacity under climatic and market uncertainty in Nepal

Climate change imposes new challenges for small-scale farmers in Nepal by adding climatic uncertainty to the existing natural climate variability, and by disturbing food production systems and food markets. In conjunction with a fluctuating international labour market with low job security for unskilled migrant workers, it is likely that local, subsistence-based food production will continue to be important for household food security in rural Nepal. This dissertation studies the adaptive capacity of a small-scale farming community through the theoretical lens of flexibility. Building on Gregory Bateson’s notion of flexibility as uncommitted potentialities for change, I argue that buffers of unused capacity in factors of production, opportunities for change in crop composition, and the ability to rapidly adjust production give room to manoeuvre. Flexibility in farming gives capacity to adapt to increasingly unpredictable fluctuations in local climatic conditions and international markets for food and labour. By conducting ethnographic fieldwork and applying qualitative and quantitative fieldwork methods to a case study from the Nepali Middle Hills, I analyse flexibility at the scales of a community farming system and household farm systems. Here, as elsewhere in Nepal, foreign labour migration by young men is prevalent. However, migrants have also started to return and invest their labour in new cash crops, which add to the households’ cultivation of traditional staple crops for food. Since land holdings are small and few are fully self-sufficient from own production, additional food is bought by means of some income from cash cropping, remittances, and off-farm work. The expansion of the local range of available cultivars enables farmers to alternate between various food and cash crops, and ensures that if one crop fails, there are others to eat. Diversification, not specialization, preserves the flexibility to rapidly adjust resource utilization, crop compositions, and productive practices. A flexible combination of subsistence production and high-value crops makes an important contribution to adaptive capacity under uncertain and variable climatic and market conditions. Migration has contributed to raise household incomes through remittances but has also increased the agricultural work burden for women. Although women already take part in decision-making on the farm, their participation in public, financial and market spheres are more restricted. Local gender roles are currently changing as women have started to enter new social spheres. I find that there are two competing sets of cultural gender norms in Nepal: Modern development ideas of women’s empowerment and gender equality challenge traditional gender norms, which constrain women’s decision-making power to the household and the farm. In the local community, the ability to negotiate a new role space for women is socially differentiated. Individuals who stand strong in hierarchies of caste and ethnicity, wealth, age, and marital status are in a better position to change local gender roles than less fortunate individuals who rather feel caught in a cultural conflict of competing gender norms. In sum, cultural change in local gender roles opens for greater participation by women in public life, local markets, and microcredit cooperatives. Although income from cash cropping is an attractive option for returned migrants, the households’ production strategy is not primarily driven by a desire to maximise profit. Cash cropping is considered a high-risk option and an alternative to migration, but not an alternative to subsistence food production. I find that people combine two production logics: They apply the profit-motivated market logic on a small share of their land, while keeping most of their land for food production for own consumption. According to the subsistence logic, the main purpose of farming is to ensure a stable access to food for the household by means of own production, to contribute to and benefit from reciprocity-based systems for sharing food and labour in the community, and to maintain social ties and traditions. The current agricultural development strategy of the Nepali Government regards subsistence production as an impediment to economic growth, and advocates a transformation of Nepali agriculture into large-scale, mechanized, specialized, and commercial production units. Implementing this strategy may improve the agricultural sector’s economic performance and reduce Nepal’s dependency on food imports, but it would not ensure stable access to food for rural farming households. The farmers’ strategy to balance subsistence and market production, and maintain social security systems in the community, enhances their food security and adaptive capacity. Theoretically, I distinguish between two levels of abstraction and argue that in a dynamic and uncertain environment, flexible adaptation at one level of abstraction helps ensure the general sustainability of the system at a higher level. Ensuring the sustainability of small-scale farm systems means to maintain their ability to provide people with food and a livelihood, often in combination with off-farm activities. Unless national policies that severely restrict the farmers’ flexibility are implemented, or the impacts of climate change turn out to exceed the limits of adaptive capacity in this community, small-scale subsistence farming is likely to persist in Maina Pokhari

Flexible adaptation in Himalayan small-scale farming : Subsistence production, gender relations, and adaptive capacity under climatic and market uncertainty in Nepal

Climate change imposes new challenges for small-scale farmers in Nepal by adding climatic uncertainty to the existing natural climate variability, and by disturbing food production systems and food markets. In conjunction with a fluctuating international labour market with low job security for unskilled migrant workers, it is likely that local, subsistence-based food production will continue to be important for household food security in rural Nepal. This dissertation studies the adaptive capacity of a small-scale farming community through the theoretical lens of flexibility. Building on Gregory Bateson’s notion of flexibility as uncommitted potentialities for change, I argue that buffers of unused capacity in factors of production, opportunities for change in crop composition, and the ability to rapidly adjust production give room to manoeuvre. Flexibility in farming gives capacity to adapt to increasingly unpredictable fluctuations in local climatic conditions and international markets for food and labour. By conducting ethnographic fieldwork and applying qualitative and quantitative fieldwork methods to a case study from the Nepali Middle Hills, I analyse flexibility at the scales of a community farming system and household farm systems. Here, as elsewhere in Nepal, foreign labour migration by young men is prevalent. However, migrants have also started to return and invest their labour in new cash crops, which add to the households’ cultivation of traditional staple crops for food. Since land holdings are small and few are fully self-sufficient from own production, additional food is bought by means of some income from cash cropping, remittances, and off-farm work. The expansion of the local range of available cultivars enables farmers to alternate between various food and cash crops, and ensures that if one crop fails, there are others to eat. Diversification, not specialization, preserves the flexibility to rapidly adjust resource utilization, crop compositions, and productive practices. A flexible combination of subsistence production and high-value crops makes an important contribution to adaptive capacity under uncertain and variable climatic and market conditions. Migration has contributed to raise household incomes through remittances but has also increased the agricultural work burden for women. Although women already take part in decision-making on the farm, their participation in public, financial and market spheres are more restricted. Local gender roles are currently changing as women have started to enter new social spheres. I find that there are two competing sets of cultural gender norms in Nepal: Modern development ideas of women’s empowerment and gender equality challenge traditional gender norms, which constrain women’s decision-making power to the household and the farm. In the local community, the ability to negotiate a new role space for women is socially differentiated. Individuals who stand strong in hierarchies of caste and ethnicity, wealth, age, and marital status are in a better position to change local gender roles than less fortunate individuals who rather feel caught in a cultural conflict of competing gender norms. In sum, cultural change in local gender roles opens for greater participation by women in public life, local markets, and microcredit cooperatives. Although income from cash cropping is an attractive option for returned migrants, the households’ production strategy is not primarily driven by a desire to maximise profit. Cash cropping is considered a high-risk option and an alternative to migration, but not an alternative to subsistence food production. I find that people combine two production logics: They apply the profit-motivated market logic on a small share of their land, while keeping most of their land for food production for own consumption. According to the subsistence logic, the main purpose of farming is to ensure a stable access to food for the household by means of own production, to contribute to and benefit from reciprocity-based systems for sharing food and labour in the community, and to maintain social ties and traditions. The current agricultural development strategy of the Nepali Government regards subsistence production as an impediment to economic growth, and advocates a transformation of Nepali agriculture into large-scale, mechanized, specialized, and commercial production units. Implementing this strategy may improve the agricultural sector’s economic performance and reduce Nepal’s dependency on food imports, but it would not ensure stable access to food for rural farming households. The farmers’ strategy to balance subsistence and market production, and maintain social security systems in the community, enhances their food security and adaptive capacity. Theoretically, I distinguish between two levels of abstraction and argue that in a dynamic and uncertain environment, flexible adaptation at one level of abstraction helps ensure the general sustainability of the system at a higher level. Ensuring the sustainability of small-scale farm systems means to maintain their ability to provide people with food and a livelihood, often in combination with off-farm activities. Unless national policies that severely restrict the farmers’ flexibility are implemented, or the impacts of climate change turn out to exceed the limits of adaptive capacity in this community, small-scale subsistence farming is likely to persist in Maina Pokhari

From bullets to ballots : a discussion on the transformation of the Aceh conflict

At 15 August 2005, the Government of Indonesia and the Free Aceh Movement (GAM) signed a Memorandum of Understanding (MoU) which aimed at ending the separatist conflict which during 29 years have seen more than 15 000 people in the province killed. The signing of a peace agreement is not unique in Aceh; the uniqueness lies in the fact that 20 months later, Aceh is still at peace. A former GAM leader is now democratically elected as governor in the province, embodying the enduring transformation of the conflict from bullets to ballots. This thesis asks how the MoU could be possible. The study of the Aceh conflict lies at the crossroad of theory and practice, and existing theory prove inadequate in capturing the particularities of the case. Conflict resolution theory is limited in its organic view of conflict and its narrow focus on stages of conflict or settlements, and missing out on the larger picture. Conversely, the circular view of conflict transformation is better suited for the study of Aceh. Visualizing conflict as a spiral opens for a contextual search for the conditions which may serve to turn a destructive conflict spiral. However, this approach disregards the influence which the very dynamics of the negotiation process may pose on protracted issues and positions. This thesis seeks to bridge these levels by merging relevant tools from the two approaches. It first seeks to find the internal, external and relational contextual changes which facilitated a ripe moment for returning to talks in late 2004. It then discusses how the 2005 Helsinki process served to loosen up protracted positions regarding the final political status of Aceh. In particular it is argued that both GoI and GAM were forced to adapt to the new democratic environment and values after the fall of authoritarian rule in 1998. At the GoI side, the 2004 election saw a presidential change elevating to power actors who benefited from peace rather than war. At the GAM side, the adoption of democratic and non-violent rhetoric saw GAM rise to a popular movement, only to be severely repressed as the Indonesian military introduced Martial Law in 2003. This thesis argues that by late 2004, GAM might be facing a hurting stalemate, but that there existed no visible Way Out to induce them to resume negotiations before the Indian Ocean Tsunami struck Aceh, killing an incomprehensible number of 160 000 people. The following negotiations in Helsinki followed a comprehensive formula in which the core contradictions of the conflict had to be agreed on before even small matters could be agreed on. This added pressure on the parties, but the situation drew towards a stalemate on the core issue of the political status of Aceh. The great turning point came as GAM put their independence claim aside and rather demanded a self-governing solution; ending the 29 years impasse by opening a bargaining space for details which not previously had existed. This remarkable change of goals is seen to reflect a gradual transformative process within GAM, though the final step must be ascribed to the dynamics of the negotiation process. Still, the situation drew towards a second stalemate on one final issue as GoI was reluctant to allow for local political parties in Aceh, and hence provide GAM with an opportunity to represent itself politically. In the final hour GoI gave way, allowing for the MoU to be signed

National specialization policy versus farmers’ priorities: Balancing subsistence farming and cash cropping in Nepal

The Nepali Government is currently implementing policies for a radical agricultural transformation into large-scale, mechanized, specialized and commercial farming. However, the peasants prioritize diversified subsistence production of resilient and versatile food crops and regard cash crops only as a supplement. Cash cropping represents a potentially profitable income source but involves risk. Complete agricultural commercialization would jeopardize household and community food security, weaken trust- and reciprocity-based social mechanisms for exchanging food and labour, and break with traditions. Peasants’ motivations for balancing subsistence and market production are multiple and interrelated because their economic pursuits are deeply embedded in social and cultural structures

Farming Flexibility in Mustang, Nepal. Potentialities and constraints under conditions of climate change

Climate change is projected to involve rising average temperatures and more rapid melting ofice and snow in the Himalaya. Increased seasonality in river discharge and substantialreductions in regional food production are probable consequences from these changes. Theneed is thus present to investigate the potentials for local agricultural production in the face ofclimate change. In the highly diverse Himalayan region, however, climate projections at thelocal scale are rather uncertain. Therefore, people’s ability to maintain local agriculturalproduction will probably depend on how flexible the local farming systems are to adjust tounpredictable changes, particularly in temperature and water availability.The objective of this thesis is to study the flexibility of one such farming system which islocated in Mustang, Nepal Himalaya. Defining flexibility as ‘uncommitted potentialities forchange’, the thesis identifies opportunities for change in the farming system, as well as factorsthat constrain this flexibility. Further developing the concept of flexibility, it is suggested thatflexibility may be analysed in terms of type, scope and temporal flexibility. Although thereare several underexploited resources in the studied farming system, the present situation is notregarded as one of irrational and suboptimal exploitation of resources. Instead, unexploitedresources imply opportunities for change, which provide the system with flexibility to rapidlyadjust agricultural production to varying weather conditions. However, there are limits toflexibility. In an interlinked farming system, lack of one resource, such as water for irrigation,may constrain the general performance of the system. Still, as long as the seasonal availabilityof irrigation water is not drastically altered or reduced, the farming system is probably flexibleenough to enable people to increase their reliance on local agricultural production also in theyears to come

Constraints on planetary orbital evolution theories from detection of multiple transits

As observations of planetary systems are published from the Kepler mission more constraints can be put on the theory of planetary formation and evolution. This in turn can be used to more accurately tell what really has been observed, such as the frequency and orbital parameters with which a six planet system like the one around Kepler-11 will occur. Even if a system has been observed to have four transiting planets it is not necessarily true that it only have four planets. Here a simple computer model is created for planetary systems consisting of a given number of planets with certain orbital parameters in order to calculate the frequency with which a certain number of transits will be seen. This is then tied to the data from the Kepler mission to make a rough prediction of the frequency for planetary systems with different number of planets. It is predicted that 3% of the observed systems have six planets, 13% have four planets and 14% have two planets. The other types of systems have very small and even negative prevalence. The conclusion of this is that this model is too simple or the assumptions are wrong