Nitrogen (N) deposition has increased globally over the last 150 years and further increase is predicted for the future. Nitrogen is an important nutrient for lichens, involved in many processes in both photobiont and mycobiont.  However, N can be a stressor, causing many lichens and lichen communities to disappear with increased deposition. The objective of this thesis was to investigate the response of epiphytic lichens to increased N load. This was done by simulating an increased N deposition to lichens in a boreal forest with low background N, including both short term studies with transplanted lichens and long term studies of naturally established lichens. Alectoria sarmentosa was used as a model species for a N-sensitive lichens and Platismatia glauca as a relatively more N-tolerant lichen. Nitrogen deposition was simulated by daily spraying during the growing season with water and isotopically labeled ammonium nitrate (NH4NO3). In Paper I, I found that when N is supplied in realistic doses (equivalent to deposition of 0.6, 6, 12.5, 25 and 50 kg N ha-1), there were no significant differences in uptake of NO3- or NH4+ in either of the lichen species. The results in Paper II indicate that A. samentosa may be limited by phosphorous (P) and not N limited as expected. That study highlights the importance of P, when studying the effects of N deposition, since P can both mitigate and intensify the negative effects of N on epiphytic lichens. Paper III shows that four years of simulated N deposition caused an alteration of the epiphytic lichen community, since A. sarmentosa decreased in the highest N loads (25 and 50 kg ha-1 year-1), Bryoria spp. decreased to 12.5 kg N and higher loads and Hypogymnia physodes decreased over time for all treatments except in 12.5 kg ha-1, where it only decreased during the first treatment year and then increased after 2007.  The abundance of Platismatia glauca increased over time, independent of treatment. As hypothesized, responses to the treatments differed among species, reflecting their different N optima. In paper IV, the effects of N on carbon-based secondary compounds were studied. None of the studied species (P. glauca, A. sarmentosa, Lobaria scrobiculata and Xanthoria aureola) reduced their concentration of secondary compounds during the experimental period, but in P. glauca the concentration of all compounds were significantly lower in N treated thalli compared with control thalli. The results are consistent with a high degree of constitutive defence in three of the four studied lichens, and we conclude that all four studied lichens seem to have a robust chemical defence system despite considerable manipulation of the environmental conditions. However, we don't know if these lichens are able to keep up the high protection level over longer periods comprising a number of years when more new tissue is formed. In conclusion, long term experiments are necessary to understand lichen response to environmental changes.

Paper 1: Give More Tomorrow Many charities ask donors to commit to monthly contribution schemes. Monthly contributors give a fixed sum every month, which is automatically deducted from their bank account. These donors are the most profitable ones for a charity. On average, they give more than donors who contribute sporadically. They also facilitate the long-run financial planning of the charity, and they reduce the administrative and fundraising costs. What will influence a donor's decision to commit to a monthly contribution scheme? If the costs and benefits associated with contributing to a charity occur at different points in time, the answer will depend on the donor's inter-temporal preferences. More specifically, it will be of importance whether donors are time consistent or whether they exhibit present-biased preferences.  This paper designs and tests a fundraising strategy that allows for present-biased preferences among donors. The strategy, Give More Tomorrow, was implemented as a randomized field experiment in collaboration with a large charity. 1134 donors that make monthly contributions were randomly assigned to one of two treatment groups. In the first group, monthly donors were asked to increase their donation starting immediately. In the second group, monthly donors were asked to increase their donations starting two months later. Mean donations were 32 percent higher in the latter group, a highly significant difference. Donations conditional on giving were also significantly higher in the latter group. The effect of the GMT strategy is economically large and highly profitable to the charity. Paper 2: Crowding Out or Crowding In? The crowding-out hypothesis says that private givers, who are also taxpayers, will use their tax-financed donations as a substitute for their voluntary donations, thus reducing the net effectiveness of grants (Warr, 1982, 1983; Roberts, 1984; Bernheim, 1986; and Andreoni, 1988). While theory predicts a one-to-one relationship between government grants and private donations, econometric and experimental studies have found evidence of partial or no crowding out (see, e.g., Khanna et al., 1995; Payne, 1998; Khanna and Sandler, 2000; and Okten and Weisbrod, 2000). A recent contribution to this literature argues that government grants reduce the organizations' fundraising efforts, which may indirectly cause a decrease in private contributions (Andreoni and Payne, 2003). This paper employs a previously unexplored panel dataset to test whether government grants crowd out private donations to charitable organizations, controlling for changes in the organizations' fundraising behavior. The data covers all registered charitable organizations in Sweden between 1989 and 2003. We have a total of 361 organizations where the largest group is health related. The panel data allows us to control for unobserved organizational heterogeneity and time fixed effects. Furthermore, we use a 2SLS specification to control for possible endogeneity in government grants and fundraising expenditures. Complete crowding out can be strongly rejected. In the 2SLS regression, the estimated crowd-out is small and highly significant in the full sample, on average 5.0%. In the disaggregated sample, we cannot reject zero crowding out for any type of organization in the 2SLS regressions. Furthermore, we find strong evidence that organizations are net revenue maximizing, indicating that fundraising activities are efficient. Paper 3: Is Foreign Aid Paternalistic? (with Ola Granstrom and Felix Masiye) In this paper, we experimentally investigate whether donors are paternalistically altruistic when contributing to foreign aid. A paternalist may be defined as someone who advances other people's interests, such as life, health, or safety, at the expense of their liberty or autonomy. In economic theory, a donor is said to be paternalistically altruistic if he cares about a recipient's wellbeing, but does not fully respect the recipient's preferences (Pollak, 1988; Jones-Lee, 1991, 1992; Jacobsson et al., 2005). In a double-blind experiment, a subject chooses whether to make a monetary or a tied transfer (mosquito nets) to an anonymous household in Zambia. Recipients have revealed preferences for money, as their willingness to pay for mosquito nets is positive but below the market price. A monetary transfer will therefore preserve the household's preferences while a tied transfer is paternalistic. The mean donation of mosquito nets differs significantly from zero, thereby implying paternalistic preferences among donors. Paternalistic donors constitute 65 percent of the total sample, whereas purely altruistic donors constitute 15 percent. We conclude that health-focused paternalistic rather than purely altruistic preferences dominate the foreign-aid giving of individuals. Paper 4: Altruism without Borders? (with Ola Granstrom) Why do individuals contribute to foreign aid? Does the willingness to give increase the more we know about the recipients? Although there is some literature on the strategic interests of countries in providing foreign aid, (see, e.g., Alesina and Dollar, 2000) very little is yet known about which preferences guide the foreign-aid giving of individual donors. This paper experimentally tests altruism over borders. We design a cross-country dictator game where the degree of identification of the recipient is varied in four treatments: (1) anonymity, (2) photo, (3) information and (4) photo and information. In addition, questionnaire data on donor characteristics is gathered. The mean donation is 55%, which is considerably higher than in standard dictator games. In contrast to previous within-country experiments, we find no significant effect of identification on donations. Furthermore, we find that women donate significantly more than men (64 compared to 50 percent) and that those who state that aid is too large donate significantly less than those who state that aid is too small (24 compared to 67 percent). / Diss. Stockholm : Handelshögskolan, 2006 S. 5-7: Summary of Papers, S. 13-125: 4 papers

No description available.

Le potassium est un nutriment essentiel à la croissance et au développement des plantes. Les minéraux argileux dans les sols représentent un important réservoir de K disponible pour les plantes. L'extraction de K fixé à partir de l'espace interfoliaire des minéraux micacés 2:1 peut entraîner une augmentation de la distance feuillet à feuillet qui peut être mesurée par diffraction des rayons X . Des échantillons de l'expérience Morrow Plots continue avec du maïs (C) ou du maïs-avoine-foin (R), provenant de sous-parcelles fertilisées (F) et non fertilisées (U) pour les années 1904, 1957, 1980, 1997 et 2013-2014, ont été soumis au fractionnement granulométrique séquentiel pour obtenir la fraction limoneuse (50-2 um) et les sous-fractions argileuses (2-0,2, 0,2-0,05 et <0,05 um). Les résultats granulométriques montrent une hétérogénéité significative malgré la petite taille de la MP, et un gain de sous-fraction < 0,05 um avec le temps. La modélisation des diagrammes de diffraction des rayons X a été effectuée pour obtenir une identification concluante de l'assemblage de minéraux argileux et évaluer l'impact de 110 ans d'agriculture continue et de différentes pratiques agronomiques. Un assemblage complexe de minéraux argileux a été identifié avec jusqu'à onze contributions différentes nécessaires pour reproduire les données expérimentales de sous-fractions de moins de 2 um, y compris jusqu'à six couches mixtes d'illite-smectite-chlorite. L'analyse de phase quantitative pour toutes les sous-parcelles et toutes les années, a montré que l'assemblage minéral du MP est similaire entre les différentes sous-parcelles, quel que soit le traitement agronomique. Aucune preuve significative d'altération ou de transformation des phases minérales argileuses n'a été observée au fil du temps. La nature dioctaédrique des minéraux argileux de la MP désavantage l'extraction du K et donc la dissolution est le mécanisme privilégié pour l'absorption du K et la perte de sous-fractions 2-0,2 et 0,2-0,05 um est attribuée à ce processus. / Potassium is an essential nutrient for plant growth and development. Clay minerals in soils represent an important reservoir of plant-available K. Extraction of fixed K from the interlayer space of micaceous 2:1 minerals can lead to an increase in the layer-to-layer distance which can be measured by X-ray diffraction. Samples from the Morrow Plots continuous corn (C) and corn-oats-hay (R) experiment, from fertilised (F) and non-fertilised (U) subplots for the years 1904, 1957, 1980, 1997 and 2013-2014 were subjected to sequential size-fractionation to obtain the silt fraction (50-2 um) and clay-sized subfractions (2-0.2, 0.2-0,05 and <0.05 um). Granulometric results show siginificant heterogeneity despite the small size of the MP, and a gain in <0.05 um subfraction with time. Full-profile fitting of X-ray diffraction patterns was performed to obtain conclusive identification of the clay mineral assemblage and assess the impact of 110-years of continuous agriculture and different agronomic practices. A complex clay mineral assemblage was identified with up to eleven different contributions necessary to reproduce the experimental data of <2 um subfractions, including up to six illite-smectite-chlorite mixed-layers. Quantitative phase analysis for all subplots and years showed that the mineral assemblage of the MP is similar between different subplots, regardless of agronomic treatment. No significant evidence of alteration or transformation of clay mineral phases was observed over time. The dioctahedral nature of the clay minerals of the MP disfavours K-extraction and thus dissolution is the favoured mechanism for K-uptake and the loss of 2-0.2 and 0.2-0.05 um subfractions is attributed to this process.

Dar nitidez aos sentimentos e razões que emergem das experiências dos vestibulandos de Vitória-ES, entre 2009-2010, e que os movem em direção a seus projetos profissionais é objetivo deste trabalho. A noção de projeto aqui utilizada (VELHO, 1999) afasta-se da clássica compreensão liberal do ser humano, autônomo, livre e único, responsável por seus sucessos e fracassos, subjacente a estudos sobre escolha profissional. A ideia proposta é que campo de experiências dos sujeitos marca seus projetos profissionais, mas que suas condutas deliberadas, não necessariamente racionais, expõem certas expectativas de vida, quaisquer que sejam as posições sociais desses sujeitos. Para o exame dessas expectativas, esses sujeitos foram vistos em suas relações sociais - nas interseções de classes, gênero, de cor da pele, de gerações, etc. Reconheceu-se, ainda, que razões e sentimentos (WILLIAMS, 1969), também forjam projetos profissionais de sujeitos sob diversas condições sociais e apesar delas. Por considerar que esses projetos portam manifestações humanas, nem sempre perceptíveis e tantas vezes encobertas, a metáfora do rizoma (DELEUZE; GUATTARI, 2004), foi de utilidade metodológica. Alguns indícios (GINZBURG, 2007), sugeriram caminhos de pesquisa e alguns dos significados aos sujeitos para que esses projetos pudessem ser detectados. A perspectiva da longa duração histórica e dos tempos múltiplos presidiu o exame de trajetórias selecionadas de um conjunto de sujeitos pesquisados entre os anos 2009-2010, o que favoreceu a percepção de continuidades históricas, mas também a ocorrência de mudanças de certas tendências sociais. Dois cursos de pré-vestibular, um público e um privado, em Vitória, ES, nessa conjuntura, mostraram um pouco da pluralidade de expectativas de diferentes jovens - pobres, de classes média e alta, homens e mulheres, brancos, negros e pardos, mais novos e mais velhos em relação ao ensino superior presente em seus projetos profissionais. Razões e sentimentos que os movem e que se movem, nem sempre examinados em estudos sobre a matéria, foram expostos. Contribuições de Elias (1990), de R. Williams (1969), de Bourdieu (2003, 2009), de E. P. Thompson (2002), de Löwy (1990), entre outros, apoiaram evidências de que as relações indivíduo e sociedade, sempre plurais e complexas, expressam apenas partes de seus sentidos civilizadores. Para reduzir incertezas, recorreu-se a dados macrossociais e microssociais (REVEL, 1998). Entrevistas com tais jovens e coordenadores de seus cursos, observações advindas de dinâmica de grupo e, também, exame de publicações oficiais, de periódicos de divulgação de matéria sobre vestibular, entre 2009-2010, situaram um trato de escalas analíticas de difícil exercício. Para além das relações de classes, gênero, cor da pele, geração etc., pode-se concluir que esses sujeitos, por razões e sentimentos variados, com seus projetos profissionais, tanto se deslocam de suas posições sociais de origem como as mantêm, mas todos, em suas novas experiências e de diferentes modos, também se preparam para atuar sobre os sentidos civilizadores de seu tempo. / Provide clarity to the feelings and reasons that emerge from the experiences of the students in Vitória-ES, between 2009-2010, and what move them toward their professional projects is the goal of this work. The notion of design used here (Velho, 1999) differs from the classical liberal understanding of human being, autonomous, free and unique, responsible for their successes and failures, underlie to studies on "career choice". The proposed idea is that the field experiences of the subjects mark their professional projects, but their deliberate conduct, not necessarily rational, expose certain life expectations, whatever is the social position of these individuals. To test these expectations, these subjects were seen in their social relations on the intersections of class, gender, ethnicity, generations, etc. It was recognized also that the reasons and feelings (WILLIAMS, 1969) also forge professional projects of subjects under different social conditions and in spite of them. Considering that these projects carry human manifestations not always visible, often covered, the metaphor of "rhizome" (DELEUZE; GUATTARI, 2004) was useful as methodology. Evidences (GINZBURG, 2007) suggested research paths and some of the meanings attributed by those subject to these projects could be detected. The prospect of long-term historical and multiple times chaired the examination of trajectories of a selected group of subjects studied between the years 2009-2010, which favored the perception of historical continuities, but also the occurrence of certain changes in social trends. Two pre-university courses, one public and one private, in Vitória, ES, at this juncture, showed a bit of a plurality of different expectations of young people - poor, middle and upper classes, men and women, whites, blacks and browns, younger and older in relation to high school - present in their professional projects. Reasons and feelings that move them and that move is not always considered in studies on the subject, were exposed. Contributions of Elias (1990), Williams (1969), Bourdieu (2003, 2009), E. P. Thompson (2002), Löwy (1990), among others, supported evidences that the relation between individual and society, always plural and complex, express only parts of their civilizing senses. To reduce uncertainties, it was used macro and micro data (Revel, 1998). Interviews with these teenagers and advisers, observations from group dynamics and also examination of official publications, periodicals to disseminate material on vestibular, between 2009-2010, were located a tract of analytical scales difficult to exercise. Apart from relations of class, gender, skin color, generation, etc., is possible to conclude that these subjects, for reasons and various feelings, with their professional projects, move are not from their social origin, but all of them, in their new experiences and different ways, also prepare themselves to act on the senses civilizing of his time.

Comment résoudre les problèmes de congestion liés au développement urbain ? Les investissements massifs dans les infrastructures et le traitement monétaire et coercitif des comportements ayant montré leurs limites, nous proposons d'explorer la possibilité de favoriser les comportements positifs (covoiturage, vélo, télétravail). Nous commençons par élargir le modèle comportemental de l'individu en posant comme préalable à l'étude des motivations la prise en compte du cadre dans lequel il se situe. Nous justifions théoriquement cet apport principalement par les travaux du psychologue Daniel Kahneman et du sociologue Ervin Goffman. Nous précisions ensuite notre démarche méthodologique : en montrant combien la démarche des expérimentations de laboratoire est reliée à l'hypothèse comportementale de l'homo œconomicus, nous montrons la cohérence de notre hypothèse de cadre avec celle des expériences de terrain. Nous décrivons ensuite trois expériences visant à montrer (i) comment le cadre correspond à une représentation confortée par un discours dominant (ii) l’importance de la mesure rétroactive de cette représentation et (iii) comment les motivations agissent à l’intérieur de ce cadre. Nous en déduisons plusieurs principes susceptibles de favoriser un changement de comportements de mobilité à même de traiter le problème de congestion : (i) la place de l’individu dans les schémas de transports, (ii) le temps ou le bien être comme indicateur de mesure et (iii) les représentations collectives comme support de coordination. / How to solve congestion problems related to urban development? As the massive investment in infrastructure and the monetary and coercive treatment of behaviors have shown their limits, we propose instead to explore the promotion of positive behavior (carpooling, biking, telecommuting). We start by expanding the behavioral model of the individual, by taking into account the context (frame) in which it happens. We justify this contribution primarily through the work of the psychologist Daniel Kahneman and the sociologist Ervin Goffman . Then we clarify our methodological approach: by showing how the process of laboratory experiments is connected to the behavioral factors of the homo oeconomicus, we show the consistency of our frame hypothesis with field experiments. We then describe three experiments to show (i) how the frame is underpinned by a dominant discourse (ii) the importance of the retroactive measure of this representation and (iii) how motivations acts within that frame. We derive several principles to promote a change of mobility behavior able to treat congestion: (i) the place of the individual in transport schemes, (ii) using time or well-being as a measurement indicator and (iii)collective representations as coordination enablers.

As in any other sector, the Covid-19 outbreak has caused many changes in education, and there is a reasonable expectation for this intervention to have a significant impact on the students and their performance. The purpose of this study was to analyse the effects of the digital semester, imposed on students due to Covid-19 outbreak, on student academic success. Using a quasi-experimental methodological approach called dif-in-dif analysis, three empirical models were constructed to analyse if there is an overall effect when comparing our control and treatment groups, as well as if there were any group-specific differences when it comes to the performance across genders and educational levels. The study found a significant negative effect of the digital semester on student academic success, suggesting that students performed significantly worse after the Covid-19 outbreak caused the University to step away from face-to-face teaching and adapt to remote studies. Furthermore, it was found that gender-specific differences do not affect the academic performance of our treatment group; however, female students performed worse when the digital semester was implemented compared to the control group who had both the classes and exams face-to-face. Lastly, Master students were found to perform significantly worse compared to Bachelor students’ when the Covid-19 outbreak caused the education to transfer to the digital environment.

In this study, two different field experiments were designed to assess the relative influence of urbanization on benthic communities. During spring and summer, four urban and one reference sites from Denton County, Texas were selected for benthic macroinvertebrate evaluation. Statistically significant differences in colonized benthic macroinvertebrate taxa on artificial substrates were observed among the four urban sites and the reference site. Oligochaetes and chironomids were the dominant taxa at all sites. Identification of chironomid larvae at the subfamily and genus level to detect differences between sites had higher statistical power than the evaluation based on total chironomids. At the reference site, Caenis, Cladotanytarsus, Orthocladius, and Ceratopogonidae were the dominant taxa, while the urban sites were dominated by Dero, Physella, Ancylidae, Chironomus, Dicrotendipes, Glyptotendipes, Polypedilum, Pseudochironomus, Stenochironomus, and Tanytarsus. These differences may have been dependent upon differences in hydrologic regime and water quality between sites. Significant differences (ANOVA, p < 0.01) in water quality parameters (alkalinity, hardness, nitrates, phosphates, chlorides, sulfates, calcium, magnesium, potassium, and triazine) were found among water samples collected from the reference and urban sites. During the transfer period, most of the Ephemeroptera and Trichoptera taxa and a few other taxa disappeared from artificial substrates that were colonized at the reference site and then moved to the urban sites. Also, local abundant taxa from the urban site significantly (t test, p < 0.05) increased in number on the transferred artificial substrates. Seasonal differences in colonization patterns were also observed between the spring and summer experimental periods, which indicate that temporal variation is equally important, as is the anthropogenic effect in benthic community evaluation. Field survival and growth experiments using Erpetogomphus designatus larvae were designed to detect differences between evaluated sites. Larvae were collected from the reference site, measured in the laboratory, and exposed at the urban sites for six weeks in using specially designed cages. The exposed larvae demonstrated a higher mortality rate at the urban sites compared to the reference site.

No description available.

This study aims to examine whether women are being discriminated against at the initial contact of a small business transfer. Existing research shows that men dominate in entrepreneurship and that entrepreneurship is generally associated with being a man. Based on social psychological theory on gender stereotypes and economic theory on statistic discrimination we assumed that female buyers are discriminated against at the market for small business transfers. To study this, a pre-registered randomized field experiment was conducted in which we expressed interest in buying a business from fictional potential buyers to 906 business owners that had announced their business for sale on the Swedish marketplace Blocket. The gender of the fictional potential buyers was signaled through randomly assigned first names that are associated with being a man or a woman. We studied the share of messages that led to Response or Positive response from the sellers. Our results revealed that people selling their businesses are not less likely to respond to potential female buyers, meaning that women are not discriminated against at the initial contact of a business transfer. However, we did find that female buyers have a higher probability than male buyers of receiving a Positive response from a seller with a business in a female dominated industry. Corresponding advantage for male buyers compared to female buyers among sellers with businesses in male dominated industries could not be found. The experiment is the first to examine gender discrimination in the market for small business transfers. / Denna uppsats dokumenterar en studie som undersökte huruvida kvinnor blir diskriminerade som potentiella köpare på marknaden för mindre företagsöverlåtelser vid den initiala kontakten med säljare. Tidigare forskning visar att entreprenörskap domineras av män och att företagande i allmänhet ofta förknippas med att vara en man. Med utgångspunkt i socialpsykologisk teori kring könsstereotyper och ekonomisk teori om statistisk diskriminering antog vi att kvinnliga köpare diskrimineras på marknaden för mindre företagsöverlåtelser. För att testa vår hypotes genomförde vi ett förregistrerat randomiserat fältexperiment där vi meddelade intresse från fiktiva köpare till 906 verkliga företagsägare som utannonserat sina företag för försäljning på Blocket. Köparnas kön signalerades genom att slumpmässigt ange förnamn som förknippas med kvinnor respektive män. Vi studerade andelen intressemeddelanden som ledde till en Respons och en Positiv respons från säljarna. Resultaten visade att kvinnliga köpare inte var mindre sannolika än manliga köpare att erhålla en Positiv respons från säljaren på deras intressemeddelanden. Däremot visade resultaten att kvinnliga köpare hade högre sannolikhet än manliga köpare att erhålla en Positiv respons från säljare med företag i typiskt kvinnodominerade branscher. Motsvarande fördel för manliga köpare jämfört med kvinnliga köpare bland säljare med företag i typiskt mansdominerade branscher kunde ej observeras. Experimentet är det första som undersöker könsdiskriminering vid marknaden för företagsöverlåtelser.