The Jacobian Conjecture is a long-standing open problem in algebraic geometry. Though the problem is inherently algebraic, it crops up in fields throughout mathematics including perturbation theory, quantum field theory and combinatorics. This thesis is a unified treatment of the combinatorial approaches toward resolving the conjecture, particularly investigating the work done by Wright and Singer. Along with surveying their contributions, we present new proofs of their theorems and motivate their constructions. We also resolve the Symmetric Cubic Linear case, and present new conjectures whose resolution would prove the Jacobian Conjecture to be true.

The Jacobian Conjecture is a long-standing open problem in algebraic geometry. Though the problem is inherently algebraic, it crops up in fields throughout mathematics including perturbation theory, quantum field theory and combinatorics. This thesis is a unified treatment of the combinatorial approaches toward resolving the conjecture, particularly investigating the work done by Wright and Singer. Along with surveying their contributions, we present new proofs of their theorems and motivate their constructions. We also resolve the Symmetric Cubic Linear case, and present new conjectures whose resolution would prove the Jacobian Conjecture to be true.

Uppsatsen syftar till att söka svaren på frågor om vilka maskuliniteter som uppstår i Jan Fridegårds ursprungliga trilogi om Lars Hård samt hur dessa maskuliniteter uppstår, varierar och upprätthålls. Undersökningen utgår från teorier formulerade av bland andra Judith Butler och Raewyn Connell; teorier som vill förklara både genus och kön som sociala konstruktioner. Arbetet bygger vidare på ett forskningsläge om manlighet i litteraturen som främst kan karaktäriseras som internationellt, eftersom den svenska litteraturvetenskapliga manlighetsforskningen ännu är förhållandevis blygsam. Undersökningen kan delas in i tre delar som i tur och ordning behandlar maskuliniteter som uppstår i Lars Hårds relationer till kvinnor, till andra män och till samhällets institutioner. I Lars Hårds relationer till kvinnor söker han främst konstruera sin maskulinitet genom att söka efter en stabil och naturlig femininitet att spegla denna maskulinitet mot; något som i allt väsentligt misslyckas. I hans interagerande med andra män visar sig en maskulinitet präglad av distansering från familjen och de plikter som därmed associeras. Denna maskulinitet uppstår främst i grupper av män; grupper som även präglas av hierarkier och dominans av andra män. Denna maskulinitet skiljer sig från den som uppstår i trilogins manliga vänskapspar, som snarare kännetecknas av omsorg och ömsesidig respekt. I det avsnitt som fokuserar Lars Hårds relationer med samhällets institutioner behandlas först familjen, inom vilken de traditionella könsrollerna tydligt framträder: Lars Hårds mor står för omsorgen och det verklighetsnära, medan fadern ägnar sig åt mer eller mindre verklighetsfrånvänd bildning under lediga stunder. När modern insjuknar tas hennes plikter över av Lars Hård, som i och med detta förefaller uppleva sig befriad från maskuliniteternas tvångsmässiga distansering från den reproduktiva sfären. Därefter fokuseras det främmandeskap Lars Hård känner inför sin kropp, hur han förefaller se på denna kropp i det moderna samhället samt straffsystemets reduktion av hans individ till just en kropp; något han själv gjort sig skyldig till i sin syn på kvinnan. Slutligen tas i undersökningen upp den urtidsman Lars Hård ibland identifierar sig med; hur denna maskulinitet yttrar sig samt hur den skulle kunna sättas i samband med det samhälle som under mellankrigstiden snabbt omvandlades.

<p>Fungal pathogens likely play an important role in regulating populations of tree seedlings and preserving forest diversity, due to their ubiquitous presence and differential effects on survival. Host-specific mortality from natural enemies is one of the most widely tested hypotheses in community ecology to explain the high biodiversity of forests. The effects of fungal pathogens on seedling survival are usually discussed under the framework of the Janzen-Connell (JC) hypothesis, which posits that seedlings are more likely to survive when dispersed far from the parent tree or at low densities due to pressure from host-specific pathogens (Janzen 1970, Connell 1971). One of the key challenges to assessing the importance of JC effects has been to identify and quantify the effects of the large numbers of potential pathogens required to maintain host diversity. The primary objectives of this research were to (1) characterize the fungi associated with seedling disease and mortality for a number of important southeastern US forest tree species; and (2) determine if these associations are consistent with the Janzen-Connell hypothesis in terms of differential effects on seedling survival.<br></p><p>Culture-based methods and ribosomal DNA (rDNA) sequencing were used to characterize the fungal community in recently dead and live seedlings of thirteen common tree species in a temperate mixed hardwood forest (North Carolina, USA), with the goal of identifying putative seedling pathogens. Cultures were initially classified and grouped into 130 operational taxonomic units (OTUs) using 96% internal transcribed spacer (ITS) sequence similarity; 46% of all OTUs were found only once. Using rarefaction, it was concluded that the richness of the system was not fully sampled and likely included over 200 taxa (based on non-parametric richness estimators). Species richness did not differ between sampling sites or among the five most common hosts sampled. The large ribosomal subunit (LSU) region of rDNA was then sequenced for representative samples of common OTUs and refined identifications using a constrained maximum likelihood phylogenetic analysis. Phylogenetic placement verified strong BLAST classifications, and allowed for placement of unknown taxa to the order level, with many of these unknowns placed in the Leotiomycetes and Xylariales (Sordariomycetes).<br> </p><p>Next, a hierarchical Bayesian model was developed to predict the effects of multiple putative fungal pathogens on individual seedling survival, without forcing the effects of multiple fungi to be additive. The process of disease was partitioned into a chain of events including incidence, infection, detection, and survival, and conditional probabilities were used to quantify each component individually, but in the context of one another. The use of this modeling approach was illustrated by examining the effects of two putative fungal pathogens, <italics>Colletotrichum acutatum</italics> and <italics>Cylindrocarpon</italics> sp. A, an undescribed species of <italics>Cylindrocarpon</italics>, on the survival of five seedling hosts in both a maximum likelihood and Bayesian framework.<br> </p><p>Finally, the model was used to assess the impacts of these fungi on seedling survival, alone and in combination, using data on five potential fungal pathogens and five hosts. Multi-host fungi had differential effects on seedling survival depending on host identity, and multiple infections may impact survival even when single infections do not. Evaluating these interactions among multiple plant and fungal species generates a set of targeted hypotheses of specific plant-fungal combinations that could help us better understand pathogen-driven diversity maintenance at larger scales than previously possible. Building on these results, some recommendations are provided as to how the Janzen-Connell hypothesis can be re-evaluated with respect to host specificity, pathogen distribution, and environmental context.</p> / Dissertation

Natural enemies are ubiquitous in nature. In many communities, natural enemies have a major effect on the diversity of their prey. Their effects are very diverse: they can promote or undermine the ability of their prey to coexist through a variety of mechanisms. As such, an important step in understanding how diversity is maintained will be to understand how different forms of predator behavior affect prey coexistence. In this dissertation, I study how two major types of predators affect plant coexistence in two different communities. First, I study natural enemies in tropical forests, using both theory and empirical work. In tropical forests, most natural enemies are thought have a narrow host range, and be distance-responsive (i.e., mainly harm seeds and seedlings that are near adults of their main host). Previous theoretical work has shown that specialized natural enemies can maintain diversity of their prey, whether or not they are distance-responsive. However, it is unknown whether specialist natural enemies are more or less able to promote prey coexistence if they are distance-responsive. Using theoretical models, I show that distance-responsive predators are less able to maintain diversity. Additionally, I show that habitat partitioning does not interfere with the ability of distance-responsive predators to maintain diversity, even if it causes seedling survival to be highest near conspecific adults. From an empirical aspect, I studied the host range of seed-associated fungi. Soilborne microbes, such as fungi, are thought to play an important role in maintaining diversity in tropical forests. However, the microbial community itself is often treated as a black box, and little is known about which microbes are causing major effects, or how 8 specialized seed-microbe associations are. Here I use experimental inoculations to examine the host range and effect of a guild of seed-associated fungi that are thought to be mainly pathogens. I show that fungal species are differentially able to colonize different seed species, and have species-specific effects on seed germination. I show that in many cases, plant phylogeny, and to a lesser extent fungus phylogeny, are good predictors of colonization. Finally, I study how an optimally foraging granivore can promote (or undermine) coexistence amongst annual plants, using theory. Optimal foraging theory is one of the major theories for how predators behave; despite this, little is known about whether an optimally foraging predator could promote coexistence amongst a diverse community of prey. Previous models have shown than two species can coexist due to optimal foraging, but did not test whether multiple prey can coexist, nor if the effect is altered by environmental variation. Here, I show that if the predators specialize on different prey at different times, the predators can allow multiple prey species to coexist. In this case, environmental variation has little effect on the ability of predators to maintain diversity. If the predators are generalists, they cannot maintain diversity. Additionally, I show that generalist predators will create a negative storage effect, undermining coexistence.

My intention with this essay has been to examine how men’s tears are portrayed in three chosen films and what their crying does to their masculinity. In my analysis I have used the concept of hegemonic masculinity. I have worked from the assumption that in our culture men’s crying is problematic in some sense. By using both a semiotic and a discursive method of analysis I have investigated why and how these men are crying, and I have mapped out the similarities and differences between the three films. My conclusion is that the effect on the crying man’s masculinity is largely dependant on the degree of his previous fulfillment of hegemonic masculinity.

I föreliggande studie avhandlas fenomenet afterwork. Afterwork utgör en kontext som präglas av en integrering mellan arbetslivet och privatlivet, i den meningen att arbetskollegor umgås efter arbetsdagens slut under privata former. Studiens syfte är att beskriva upplevelsen av afterwork hos informanterna som samtliga är män, fyra kockar samt fem byggnadsarbetare. Krogen har historiskt utgjort en arena för män och denna studie använder ett genusperspektiv för att undersöka hur maskulinitet reproduceras inom fenomenet afterwork. För att besvara studiens frågeställningar används en fenomenologisk ansats och empirin har insamlats med intervjuer, samt en deltagande observation under en afterwork. Empirin analyseras med hjälp av Goffmans begrepp främre och bakre region, Gusfields begrepp ”work” och ”leisure”, samt Connells och Messerschmidts begrepp hegemonisk maskulinitet för att belysa reproducerandet av maskulinitet under afterwork.   Resultaten visar att kontexten afterwork utgör en integrerad arena mellan arbetet och privatlivet där inget av det ena någonsin frångår det andra; afterwork utgör därav en förlängning av arbetsdagen då samtal om arbetet ofta förekommer. Vidare visar resultaten att studiens informanter hanterar arbetslivets krav med hjälp av alkohol och dess avslappnande effekter.   Den del av studien som behandlar maskulinitet visar att kontexten afterwork utgör en arena där olika former av maskulinitet kan påvisas. Den hegemoniska maskuliniteten reproduceras främst via arbetsrollen, där den fysiska prestationen anses högt värderad. De individer som inte upplevs uppnå den kontextuella hegemonins krav på fysisk prestation underordnas diskursivt.

Abstract I denna studie undersöks interaktion mellan karaktärer i syfte att utforska hur medierad maskulinitet och temat seriemördare uttrycks i den amerikanska tv-serien Dexter (Showtime 2006-2013). I serien får vi följa seriemördaren Dexter Morgan som drivs av ett begär att döda. Parallellt med denna centrala del av handlingen söker Dexter Morgan också sin identitet som man utanför rollen som seriemördare med avsikt att smälta in i samhällsnormen. Syftet med min studie är att belysa medierad maskulinitet i tv-serien, med huvudfokus på huvudrollskaraktären Dexter Morgan. Vidare diskuteras representation av medierad maskulinitet i relation till karaktärsdrag kopplade till kategorin seriemördare. Studiens frågeställningar lyder således: Vad är relationen mellan seriemördartemat och Dexter Morgan som medierad maskulinitet? Hur ser Dexter Morgans interaktion med tre centrala karaktärer (hans far, syster och läkare) i serien ut? Vilka egenskaper kopplat till maskulinitet respektive femininitet kan urskiljas? Förändras Dexter Morgans karaktär under seriens gång, och i så fall hur? Den teoretiska ramen domineras av R.W Connells maskulinitetsteori avseende hegemonisk, underordnad och delaktig maskulinitet. Kategorin seriemördare diskuteras utifrån tidigare forskning av Louise Nilsson och Richard Dyer. Materialet utgörs av representativa scener ur seriens handling, insamlade från olika säsonger. Det metodologiska tillvägagångssättet är baserat på narratologi i avsikt att identifiera vilka delar en berättelse vilar på. Scenanalysen utgår från Keith Selbys och Ron Cowderys narrativa analysmodell som i min studie delas upp i två steg. Steg ett innebär en deskriptiv genomgång av selekterad scen. Därefter följer analysen av scenen i ett separat stycke. Analysen påvisar att om endast två karaktärer förekommer i samma scen kan de aldrig inta samma genuskonstruktion då maktpositionering dem emellan är ständigt närvarande, beroende av de maskulina respektive feminina egenskaperna karaktärerna tillskrivs. Slutsatsen är att Dexter Morgans medierade maskulinitetsroll faller inom ramen för en traditionell maskulinitet, som verkar för att vidmakthålla ett patriarkalt samhälle, där denna hegemoniska maskulinitet förblir den genusroll som alla andra ska mätas mot. Analysen visar också på att egenskaper tillskrivna hegemonisk maskulinitet tenderar att sammanfalla med de karaktäristiska egenskaper förenat med temat seriemördare.

The aim of this study has been to examine six books about Oscar Wilde’s homosexuality during the years 1906 – 2003. I have been analyzing their descriptions about his sexual orientation and compared them to each other to see the changes through time. In order to see some clear changes the main focus was to choose time differences between the books. It was clear that the earlier writers had negative opinions and thoughts about his sexual deviation the way they described it. The writers from the older books focus on Oscar Wilde’s achievements more than his sexual orientation. The analysis was made through two theories, Michel Foucault’s theories about sexuality, power and knowledge, and the second Raewyn Connell’s theory about hegemonic masculinity. The theories have been fundamental for this study on the basis of the changes through time and how societies viewed masculinity and sexual orientations. They have also been important for the descriptions of Oscar Wilde’s feminine attitude and his addiction to his looks. My method for the essay has been a conceptual analysis. The choice of this method was not hard because it has been important to the comparison and the analysis for the writers’ usage of word descriptions of Oscar Wilde’s homosexuality. The results showed a large amount of resemblances and differences between the books, which can be seen against the background of the society and its view on homosexuality.

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-11T15:00:49Z No. of bitstreams: 2 Tese Edgar A E S Silva .pdf: 1480606 bytes, checksum: 5f83b405866d21135bd0eb3bac6eae6e (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T15:00:49Z (GMT). No. of bitstreams: 2 Tese Edgar A E S Silva .pdf: 1480606 bytes, checksum: 5f83b405866d21135bd0eb3bac6eae6e (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-02-26 / FACEPE; CNPq; CAPES / Dentre as hipóteses criadas para explicar a manutenção da diversidade de árvores em florestas tropicais, uma das mais aceitas é a hipótese de Janzen-Connell. Essa hipótese propõe que inimigos naturais diminuem a probabilidade de sobrevivência de sementes e plântulas quando estas estão adensadas ou próximas ao adulto parental. Entretanto, é provável que esse mecanismo proposto por Janzen-Connell seja menos intenso em florestas fragmentadas. Esta tese teve como objetivo avaliar se a alta densidade de determinadas espécies arbóreas em paisagens fragmentadas é resultado de um relaxamento na mortalidade dependente da densidade e distância. Foram realizados três estudos em uma paisagem fragmentada de Floresta Atlântica, comparando pequenos fragmentos florestais com áreas de floresta madura no interior de um grande remanescente. No primeiro, foram analisados os padrões de mudança nas densidades de populações arbóreas no estágio de plântula e adulto para investigar quais espécies tendem a predominar em pequenos fragmentos florestais. No segundo, foi analisada a distribuição espacial de árvores adultas e jovens para inferir se a distância entre indivíduos coespecíficos é menor nos pequenos fragmentos. No terceiro, foi realizado um experimento de predação de sementes com a espécie Tapirira guianensis para avaliar se existe uma redução na predação de sementes em pequenos fragmentos florestais. Em síntese, os resultados demonstram que: (1) apenas um pequeno grupo de espécies pioneiras apresenta um aumento na densidade populacional em pequenos fragmentos florestais, enquanto muitas espécies tendem a se extinguir localmente ou apresentar abundâncias extremamente baixas nesses fragmentos; (2) não existe uma redução na distância entre jovens e adultos coespecíficos nos pequenos fragmentos ao analisar todas as espécies, apenas quando analisadas somente as espécies pioneiras; (3) exceto pela pequena redução na distância média (2 m) entre adultos coespecíficos, não foi observada uma agregação nas populações nos pequenos fragmentos florestais; (4) não existe um relaxamento na predação de sementes dependente da distância em Tapirira guianensis. Os resultados obtidos não indicam que as mudanças observadas na estrutura das assembleias arbóreas nos pequenos fragmentos resultam de relaxamentos na mortalidade dependente da densidade e distância. Entretanto, mesmo após 200 anos, esses fragmentos ainda apresentam uma redução na diversidade de árvores.