This thesis presents theoretical work on armed group activity and empirical work on post-conflict recovery. In chapter two, I develop a general equilibrium model of violence to explain observed variation in coercive practices in conflict zones. Armed groups own land in the resource sector and allocate military resources between conflict and coercion, which assign de facto ownership over land and labour respectively. I find that coercion is higher if labour is scare relative to land, production is labour-intensive, or if one group is dominant relative to others. Furthermore, contrary to other studies, I find that coercion could decreases with price if military power is sufficiently decentralised, since conflict draws resources away from coercion. In chapter three, I evaluate a reconciliation program in post-conflict Sierra Leone. The program provides a forum for villagers to air war-time grievances, and also forges institutions designed to improve conflict resolution and build social capital. I find that respondents who received the intervention are more forgiving and are more charitable in their views of ex-combatants. Furthermore, conflict resolution improved and involvement in village groups and activities increased. However, psychological health---depression, post-traumatic stress disorder and anxiety---deteriorated. This study has direct implications for the design of transitional justice programs, as well as programs that aim to promote institutional change. In chapter four, I experimentally vary foreigner presence across behavioural games conducted in 60 communities in Sierra Leone, and assess its effect on standard measures of generosity. I find that foreigner presence substantially increases player contributions in dictator games, by an average of 19 per cent. Furthermore, the treatment effect is smaller for players who hold positions of authority; and subjects from villages with greater exposure to development aid give substantially less and are more inclined to believe that the behavioural games were conducted to test them for future aid. In chapter five, I use a model of repeated bargaining with one-sided asymmetric information to investigate the difficulties of reaching and sustaining power sharing agreements. I show that asymmetric information can explain the persistence of conflict, since learning slows down when there are future opportunities for bargaining.

My dissertation focuses on changes in health-related behavior in react to information-based intervention. The first chapter analyzes the results of a field experiment to investigate the effects of comparative information on the daily number of steps taken of adults. The second chapter further explores the effects using qualitative analysis. The third chapter intends to offer explanations in the mechanisms of the results from the first chapter. My first chapter uncovers how patterns in the daily number of steps of adults are affected by information that compares one with unknown peers. I conducted a field experiment that used fitness trackers to collect daily and minute-by-minute data on the total number of steps an individual takes in a day. Participants were randomized into a group that was provided with comparison information and a group that did not receive such information. I examined whether individuals in the two groups behaved differently during and after the intervention period. I find no clear evidence of an aggregate impact of social norms on the daily number of steps taken. However, I find individuals who are not overweight or nor married or cohabiting are more likely to be influenced by social norms. Greater treatment effects are found among individuals whose number of steps that are at the tails of the distribution curve. My second chapter reports the results of the textual data from the survey in the field experiment. I present dominant themes that emerged from answers to the open-ended essay questions in the survey. The results support that health concern, body image, appearance, psychological factors, peers and friends are major motives for being physically active. For participation in the study specifically, text messages that contain comparative information produced some improvement of the exercise level. However, participants also requested more interactions with peers, additional information provision, rewards for reaching goals. The results imply external incentives play a smaller role in promoting daily number of steps. In the third chapter, I conduct a survey experimentation to test the effectiveness of informing descriptive social norms and types of text messages in predictions about health-related behaviors. First, I investigate if errors in beliefs about activity levels exist and I find no evidence of over- or under-confidence in one’s own activity levels. Further analysis provide preliminary evidence of negative effects of informedness in predictions about one’s own behavior. However, the intention-to-treat effects of comparative information are unclear. The data provide evidence in favor of the correlation between first-order personal beliefs, not higher-order normative beliefs, in predicting an increase number of steps taken in response to intervention with text messages.

The UNderstanding Severe Thunderstorms and Alberta Boundary Layer Experiment (UNSTABLE) in July 2008 was a field project to investigate the initiation of thunderstorms in southern Alberta. Special field observations included an enhanced surface network augmented with instrumented vehicles. Upper air observations were taken from four sites every two hours. This thesis focuses on the case study day of 17 July 2008 when a dryline formed parallel to the Rocky Mountains at 1030 MDT and persisted for up to nine hours. The vapour mixing ratio changed from 4.5 to 8.5 g/kg over 5 km. We documented the spatial and temporal distribution of cloud and precipitation relative to the dryline. Initially, extensive cloud formed over the dry air to the west of the dryline, while the capping inversion at 800 mb inhibited cloud formation in the moist air. In the afternoon, convection was triggered along the dryline and severe thunderstorms were observed.

No description available.

When light energy input exceeds the capacity for photosynthesis the plant need to dissipate the excess energy and this is done through non-photo-chemical quenching (NPQ). Photochemical quenching (photosynthesis), NPQ and fluorescence are three alternative faiths of excited chlorophylls. PsbS associates to photosystem II and is involved in NPQ. The results presented in this thesis were generated on Arabidopsis plants and mainly based on wildtype Col-0 together with a mutant deficient in PsbS (npq4) and a transgene overexpressing PsbS (oePsbS). We connect light and herbivore stress and show that the level of PsbS influences the food preference of both a specialist (Plutella) and a generalist (Spodoptera) herbivore as well as oviposition of Plutella. Level of PsbS also affects both metabolomics and transcriptomics of the plant; up-regulation of genes in the jasmonic acid (JA) -pathway and amount of JA has been found in the npq4 plants after herbivory. Since many experiments were performed in field we have also characterized the field plant and how it differs from the commonly used lab plant. We have also studied the natural variation of NPQ in Arabidopsis plants both in the field and the lab. The results show surprisingly no correlation. / Överskottsenergi kan vara skadligt för en växts membran och fotosynteskomplex. Vid överskott av solenergi blir fotosystemen mättade och växten behöver därför ett sätt för att göra sig av med all överskottsenergi, detta kallas för ”icke-fotokemisk quenching” (NPQ). Fotokemisk quenching (fotosyntes), NPQ och fluoresens är tre alternativa vägar för exalterade klorofyller. PsbS är involverad i NPQ och associerar med fotosystem II. De resultat som presenteras i denna avhandling kommer från studier av modellväxten Arabidopsis thaliana (Backtrav), i huvudsak gjorda på vildtypen i jämförelse med en mutant som saknar PsbS (npq4) och en transgen som överuttrycker PsbS (oePsbS). Vi har försökt att undersöka kopplingen mellan ljus- och herbivoristress och visar här att mängden PsbS påverkar både en specialist (Plutella) och en generalist (Spodoptera) insekt vid val av föda, samt Plutella även vid äggläggning. Växternas nivå av PsbS visade sig även påverka metabolomet och transkriptomet, och vi fann en uppreglering av gener i biosyntesen för jasmonat samt mer av själva hormonet jasmonat i npq4 växter efter herbivori. Eftersom vi har gjort många av experimenten ute i fält har vi även karakteriserat en typisk Arabidopsis växt i fält samt hur denna skiljer sig från den vanligt använda lab-växten. Dessutom har vi även undersökt naturlig variation av NPQ av Arabidopsis både i fält och på lab och resultaten visar, till vår förvåning, att det inte går att finna någon korrelation mellan dessa.

This study focuses on ways that the size distribution of individuals influences the types and intensities of competitive interactions within a population of aquatic arthropod predators. Three field experiments and one laboratory experiment were designed to test for feeding interference, interference mortality, and dispersal effects within and between larval size classes of the primarily semivoltine dragonfly Tetragoneuria cynosura in Bays Mountain Lake. One field experiment documented the temporal pattern of colonization of large-mesh cylinders by the small, first-year-class larvae during a 30-day period; the results are consistent with passive (density-independent) colonization. A second field experiment examined the effect of large, second-year-class larvae at densities of 1 or 3 per cylinder (14 or 42 m-2) on colonization by small larvae; this colonization was inhibited at the high density of large larvae. In the laboratory experiment, when larvae of the two size-classes were together in the same aquarium, small larvae moved around less than when by themselves (dispersal inhibition). Thus the inhibition of colonization observed in the field may result from interference mortality, rather than from a flight response to the presence of larger conspecifics. To evaluate this interpretation, the third field experiment measured the in-situ functional response of large larvae to each other and to their small conspecific prey. Results suggest a type 1 (linear) functional response, with feeding inteference among large larvae. Moreover, the interference mortality inflicted by larger larvae on smaller conspecifics was apparently more intense on larger individuals within the small size-class. Taken together, the three field experiments and a statistical power analysis show how colonization and interference interact to determine the local density of small larvae, and why such interference effects are difficult to detect experimentally in the field.

The widespread expansion of online markets in the past decade poses several questions for platforms, firms and customers alike. An important dimension to be explored in this domain is the provision of information on e-commerce platforms - given the increasing ease with which product pages can be customized to include a vast variety of content, how do these pieces of information interact? Further, what are the specific channels through which this information eventually influences consumer decision-making? My dissertation is situated in this space, and aims to look at how consumers respond to various “cues” that are being introduced by e-commerce platforms which offer products or services that can be purchased online, and how these cues might eventually influence decision-making. In my first dissertation project, the cue I focus on is user generated content. More specifically, I study how the introduction of the Q&A technology (which enables customers to ask product-specific questions before purchase, and receive answers either from other customers or the platform itself) affects the more widely established reviews and ratings feature on e-commerce platforms. I find that the addition of Q&As leads to better matches between customers and products, higher customer satisfaction, and resultantly higher ratings. My second project examines another cue that is common in online markets, which is the advertised reference price. My goal in this project is to examine how users react to a specific variant of such prices, namely the “Starting from...” price, using data from a large scale field experiment conducted on Holidu.com. My results indicate that raising “From” prices gives users a more accurate price estimate, but it negatively impacts outbound clicks and other engagement metrics. Taken together, the two projects aim to shed light on factors that influence consumer decision-making in an e-commerce setting, and the possible mechanisms underlying this influence.

To improve meat quality and consistency, cattle feeders have moved towards implementing end-point marketing strategies (EPM) based on visual estimates of physiological characteristics. A commonly used 0.5 inch backfat target was used in this analysis. Recognizing that physiological targets will not necessarily result in profit maximization; this research developed a profit maximization rule (PMR) that accounts for the dynamics of animal growth, output prices and costs. A natural field experiment was conducted in Iowa to evaluate the potential for the PMR. One hundred twenty three fed cattle were randomly assigned into two treatments (PMR and EPM). Realized profit results indicate that EPM outperformed the PMR methodology by $24.35 per head. However, simulations that relax some experimental constraints resulted in the PMR outperforming EPM by $102.06 per head. Interestingly, the PMR did not negatively affect carcass quality. Therefore, relaxing PMR constraints in future experimental studies is expected to improve realized profitability.

Experimental willingness to pay (WTP) studies can be classified as hypothetical or non-hypothetical. In a hypothetical study, such as conjoint analysis, a subject does not need to make a real economic commitment. In contrast, in a non-hypothetical task such as in experimental auctions, a subject may need to actually buy the product. Subjects in hypothetical studies tend to overstate their true WTP. Consequently, researchers need to correct hypothetical values to obtain reliable WTP estimates. Recently, incentive-aligned and cheap talk approaches have been proposed as ways to correct for hypothetical bias. In a hypothetical task, a cheap talk script explicitly reminds the subject about the hypothetical nature of the task and its expected consequences. In an incentive-aligned task (non-hypothetical), subjects are randomly selected to physically buy the product. The objective of our study is to assess and compare the reduction of hypothetical bias in consumers’ willingness to pay for novel products by applying a generic, short, and neutral cheap talk script in a retail setting. To accomplish this objective, we employ non-hypothetical, hypothetical, and hypothetical with cheap talk treatments in our experimental design. We conducted our experimental retail study using conjoint analysis and open-ended elicitation mechanisms, utilizing Becker DeGroot Marshak (BDM) mechanism for the incentive-aligned treatments. Consistently in both elicitation mechanisms, using seemingly unrelated and random-effect Tobit techniques, we find that our cheap talk script is effective in eliminating the hypothetical bias. As expected, the hypothetical WTP values are significantly higher than the non-hypothetical values but the hypothetical values with cheap talk are not significantly different from incentive-aligned or non-hypothetical estimates. In addition, we find that open-ended estimates are significantly higher than conjoint analysis estimates and that emotions and familiarity can have significant impacts on WTP estimates.

Strip-tillage implements remove the residue from previous crops and form a seedbed ready for planting. An experiment was conducted to evaluate 5 row-cleaning devices. The proportion of residue removed by the implement was used as the performance indicator. Each of the 5 devices was evaluated at 2 speeds and orientations on the implement. The devices were tested in two blocks (fields) of corn residue (one high residue and one medium residue), and one field of wheat residue. An analysis was conducted, using a mixed-effects model, to compare the performance of the cleaners operating in the different conditions. All cleaners performed well, with no statistical difference in mean performance. All row cleaners performed more consistently in wheat residue, compared with performance in corn residue. Numerically, the consistency of the different cleaners was different, with one configuration performing less consistently than the other four. Edge-effects of the outside row unit of the implement had, in most cases, an insignificant effect on the row unit's cleaning performance.