71 |
Les capacités d'adaptations des oiseaux marins face aux changements environnementaux : le rôle de l'hétérogénéité au sein des populations / The adaptive capacities of seabirds to face environmental variability : the role of heterogeneity within populationsCornet, Cindy 02 October 2014 (has links)
La dynamique d’une population résulte de la combinaison de plusieurs traits d’histoire de vie qui sont façonnés par l’histoire évolutive de cette population. L’altération d’un de ces traits par des contraintes environnementales peut donc avoir des effets sur la persistance de la population. Les ajustements individuels de certains traits phénotypiques pourraient permettre à cette population de répondre rapidement à ces contraintes sans la nécessité immédiate d’adaptations génétiques. Durant cette thèse, la variabilité de certains traits a été identifiée chez 3 espèces sentinelles des écosystèmes polaires. Ces résultats permettent de mieux comprendre les associations entre ces traits et les pressions évolutives qui en sont à l’origine, ainsi que l’importance de traits tels que la personnalité dans la part inexpliquée de la variabilité de la valeur sélective des individus. A terme, nous pourrions ainsi mieux évaluer la capacité d’adaptation des populations face aux changements globaux. / Population dynamics is driven by several life history traits shaped by the evolutionary history of the population. The alteration of one of these traits by environmental constraints may thus have effects on the population persistence. Individual adjustments of some phenotypic traits could then enable this population to rapidly respond to these constraints without the immediate necessity of genetic adaptations. During this PhD project, we identified variability in some of these traits in 3 sentinel species of polar ecosystems. These results allowed us to better understand the associations between these traits and the evolutionary pressures underlying these associations, as well as the importance of traits such as personality in the amount of variability in individuals’ fitness that remains unexplained. In the long term, we should then be able to better gauge the adaptive capacity of populations to face global changes.
|
72 |
From NAFTA to USMCA: A Comprehensive Analysis of the Forces Producing North America's Regional Trade AgreementsWarnholtz Perez, Edgar G 01 January 2019 (has links)
On October 1, 2018, Mexican President Enrique Peña Nieto, U.S. President Donald Trump, and Canadian Prime Minister Justin Trudeau signed the United States-Mexico-Canada Agreement (USMCA), concluding 13 months of negotiations that concerned economies totaling 27.88% of world GDP. The recentness, magnitude, and relevance of the USMCA invokes a comprehensive analysis of the multidimensional factors that led to this agreement. Explaining the USMCA of 2018 requires insight of the continent’s political and economic forces that bound Canada, the United States, and Mexico with the North American Free Trade Agreement (NAFTA) of 1994. After doing so, this study then compiles a variety of works in a meta-analysis on NAFTA’s effects during the past 25 years. This paper finds that NAFTA achieved its intended goals, but failed to anticipate many negative repercussions for which it is criticized today. Then, this study investigates the demand for renegotiation of NAFTA which was triggered by Donald Trump calling it “the worst trade deal in history maybe ever” during his presidential campaign. However, when presenting the new USMCA to the press, he described it as a “wonderful new trade deal.” Therefore, study analyzes how different the USMCA is from NAFTA, and finds that the few changes are explained by a modernization of certain chapters to adapt the treaty to the digital era. These modifications heavily resonate the Trans-Pacific Partnership, a regional free trade agreement that included the U.S. until President Trump withdrew from it. What then results to be a rebranding of other agreements is predicted here to bring more political repercussions than economic change, as elections in Canada dawn later this year and in the U.S. in 2020. Ultimately, each party succeeded per its own renegotiation objectives; Mexico and Canada sought market penetration in the U.S., whereas the U.S. sought concessions and an end to NAFTA. Ratification of the USMCA is pending at the domestic level of each country, which this paper predicts will occur successfully, perhaps even before the end of 2019. Nonetheless, despite the modernization efforts involved in producing the USMCA, this paper questions whether the agreement equips these three member states to face the challenges of tomorrow.
|
73 |
Deinstitutionalization and Its Discontents: American Mental Health Policy ReformKofman, Olga Loraine 01 January 2012 (has links)
In 1963, President John F. Kennedy signed the Mental Retardation and Community Mental Health Centers Construction Act, establishing the beginnings of deinstitutionalization in the United States. By some counts, this Act was a stupendous policy success—by others, a dismal failure. 50 years later, no cohesive national mental health care policy has emerged to deal with increased rates of mental illness among the homeless and the incarcerated. However, California has made enormous strides to create a state policy which provides adequate services to the mildly, moderately, and severely mentally ill as well as adequate funding for those services through Proposition 63, the Mental Health Services Act, passed in 2004. This paper reviews mental health policy history from Colonial America to the present, paying special attention to JFK's deinstitutionalization in 1963 and the discontents that followed. It takes a special look at California's mental health care policy history and the strides the state has made to better serve the mentally ill.
|
74 |
Demographic and life-history variability across the range of a widespread herb: the role of environmental, geographical and genetic factors / Variabilidad demográfica y de historia vital en una planta de amplia distribución: el papel de los factores medioambientales, geográficos y genéticosVillellas Ariño, Jesús 21 March 2013 (has links)
Tesi realitzada al Instituto Pirenaico de Ecología (CSIC) / Widespread species have traditionally received much less attention than rare and endemic ones. However, they are crucial in macroecological patterns and in ecosystem structure and functioning. Thus, understanding the characteristics that allow widespread organisms to extend over large areas has a high interest from both theoretical and applied perspectives. One of the most frequent hypotheses to explain the success of widespread plants is that they show much wider ecological niches, and thus a high life-history and demographic variability. However, studies are often very specific and carried out over small spatio-temporal scales, which hinders a general understanding of intraspecific variation in widespread taxa. In this thesis, we span a large spatio-temporal scale and a large environmental gradient to analyze the magnitude and the possible causes of natural variation in the in the range centre and the northern periphery of the widespread herb Plantago coronopus. More precisely, we analyze variability in population dynamics, life-history traits, and genetic diversity in up to 22 populations in Europe and North Africa. We aim to explore the relation of such variability with the position of populations within the species’ range, since peripheral populations are traditionally expected to show a lower and more variable performance with respect to central populations. Additionally, we aim to analyze the effects of the most relevant environmental factors in population and individual performance at different spatial scales.
In the first chapter, we found higher values in central populations in some vital rates, such as fecundity and growth, but recruitment and density were higher in northern peripheral populations, and there were no clear differences between regions in temporal variability of vital rates. Differences in population performance across the species’ range seemed to be correlated with local precipitation and intraspecific competition. In the second chapter, differences in mean values and variability of vital rates between central and peripheral areas led to no differences in stochastic population growth rates. In addition, recruitment was the most influential vital rate for population growth rates at different spatial scales, and we found the same pattern of differentiation in population dynamics in response to environmental conditions within central and peripheral regions. In the third chapter, we reported high variation among populations in seed traits along a steep environmental stress gradient. Moreover, patterns in seed production were opposite at the fruit and the individual scale, as a strategy of populations to maximize fitness in each set of local conditions. Finally, in the fourth chapter, we found no relationship within populations between phenotypic variability and genetic diversity. Phenotypic variation was mainly shaped by precipitation variability, suggesting adaptive variation, whereas genetic diversity was correlated with the central vs. peripheral position, probably in close relation with some random demographic processes experienced by populations in the past.
Despite genetic diversity was higher in central populations, our results contradicted classical hypotheses predicting a lower demographic performance towards species’ range edges. In fact, environmental conditions seemed to have a higher influence on plant performance than the position of populations within the species’ range, which calls for the necessity of distinguishing between geographical periphery and ecological marginality in demographic studies. Overall, our study highlights the versatility of P. coronopus at different spatial scales in response to varying environmental conditions, complementing similar findings of previous research on the same taxon at smaller spatial scales. Such life-history variability seems to be a key factor for widespread plants to extend over large and heterogeneous ranges. / Las especies de amplia distribución han recibido tradicionalmente poca atención, a pesar de su importancia para la estructura y el funcionamiento de los ecosistemas. En esta tesis, se analiza la variabilidad demográfica, de historia vital y genética en una planta de amplia distribución en Europa y el norte de África (Plantago coronopus), en un total de 22 poblaciones a lo largo de gran parte del rango latitudinal de la especie (centro y periferia norte). Se pretende analizar la magnitud y las causas de esta variabilidad intraespecífica en relación con la posición de las poblaciones dentro del rango y con los principales factores medioambientales. Las poblaciones periféricas mostraron una menor diversidad genética, pero no mostraron en general un peor o más variable comportamiento demográfico en cuanto a densidad o tasa de crecimiento poblacional, contradiciendo así las hipótesis clásicas centro-periferia. Se encontró un mismo patrón de diferenciación demográfica dentro de las regiones tanto central como periférica, en relación con la variación en el régimen de precipitaciones. La tasa de reclutamiento de nuevos individuos fue el proceso del ciclo vital con mayor importancia para el funcionamiento de las poblaciones. Se encontró también una gran variación entre poblaciones en las características de las semillas (número, tamaño, mucílago y proporción de dos tipos de semilla dimórficos) en relación con el gradiente de estrés ambiental. Finalmente, la variación fenotípica dentro de las poblaciones se relacionó con la variabilidad ambiental, mientras que la diversidad genética se correlacionó con la posición central vs. periférica de las poblaciones y posiblemente con la historia demográfica de la especie. Globalmente, este estudio muestra la importancia de distinguir entre periferia geográfica y marginalidad ecológica, y sugiere que el éxito de las plantas de amplia distribución reside en una gran variabilidad demográfica y de historia vital a diferentes escalas espaciales.
|
75 |
Seasonal Variation in Quality and Survival of Nestling Tree Swallows (Tachycineta bicolor): Tests of Alternate Hypotheses2014 September 1900 (has links)
Understanding the patterns and processes that create differences among individuals in components of fitness, like the probability of survival or reproductive rates, is essential to our knowledge of population dynamics and for informing conservation efforts. For organisms in seasonal environments, early-breeding individuals regularly attain higher fitness than their late-breeding counterparts. Two primary hypotheses, related to quality and date, have been proposed to explain lower reproductive success of late breeders, but the veracity of these ideas has not been fully resolved. I tested predictions associated with these hypotheses to assess the effects of indices of parental and environmental quality on nestling quality and survival in an insectivorous passerine, the tree swallow (Tachycineta bicolor), at two widely separated breeding locations in western Canada.
I combined experiments and statistical modelling of observational data to evaluate two mechanisms proposed to contribute to seasonal decline in environmental quality: an increase in nest parasite abundance and a decrease in food abundance with later breeding dates. A parasite reduction experiment revealed a disproportionate benefit of parasite removal on length of primary feather for early-hatched nestlings, suggesting greater energetic constraints early in the breeding season. Furthermore, late-hatched nestlings from parasite-reduced nests had longer head-bill lengths than their control counterparts, and developed head-bills of similar length to those of early-hatched nestlings. Other than these findings, there were few detectable effects of parasites on nestling size, growth and immunity, as has been reported from several previous studies. Indeed, negative effects of parasites were only apparent when food (i.e., insect) biomass was considered. In a second series of experiments in which parental quality was controlled, I also tested whether food abundance declined during the breeding season, as predicted if environmental conditions deteriorate seasonally (i.e., date). Reduced reproductive success of late-breeding individuals was causally related to a seasonal decline in environmental quality. Declining insect biomass and enlarged brood sizes resulted in nestlings that were lighter, in poorer body condition, had shorter head-bills, shorter and slower growing ninth primary feathers and that were less likely to survive to fledge. Next, I asked whether results obtained from long-term mark-recapture data corroborated findings of short-term manipulations.
I examined seasonal variation in first-year apparent survival to investigate the relative influence of large-, small- and individual-scale factors associated with the quality and date hypotheses. Although parental quality was an important predictor of first-year apparent survival of tree swallows, my results further suggested that quality of parents was not the primary factor influencing seasonal variation in first-year apparent survival. Rather, findings were most consistent with the date hypothesis. The relationship between apparent survival and a direct measurement of environmental quality indicated that annual variation in moisture had important consequences for first-year apparent survival of tree swallows in Saskatchewan. First-year apparent survival probabilities were higher during wet years and wetter conditions are generally linked to greater insect abundance. In British Columbia, nestlings from larger broods were less likely to survive, possibly as a result of receiving less food. Apparent survival probabilities were also higher when food was more abundant.
I demonstrated that both parental and environmental quality influenced seasonal variation in fitness-related traits of tree swallows. However, the strongest evidence suggests that environmental quality, and in particular food abundance, had the greatest effect on seasonal variation in nestling quality, reproductive success and first-year apparent survival in tree swallows. My results highlight the importance of considering regional precipitation trends when projecting effects of climate change on demography of aerial insectivores.
|
76 |
Variation in age and size at maturation in two benthic crustaceans in the Gulf of BothniaLeonardsson, Kjell January 1990 (has links)
The thesis deals with variation in age and size at maturation in Saduria entomon and Pontoporeia affinis along a depth gradient in the Gulf of Bothnia, Sweden. I have analysed at what sizes and ages animals should mature in relation to growth and mortality conditions. The thesis also deals with predator-prey interactions within and between the two species. The isopod Saduria entomon matured during winter at an age of three years at 5 m depth in the Norrby archipelago (63° 30'N, 19° 50'E). Males matured eariier and at larger sizes (27-48 mm) than females (23-36 mm). The offspring were released in early summer. The adult size increased with increasing depth. Outside the archipelago, at 125 m depth, the sexes reached a size of 84 and 54 mm respectively. No evidence for temporal restriction in the release of the young was found at the deep area. The species was shown to have a high capacity for cannibalism on small conspecifics, although the small ones have the potential to avoid aggregations of large conspecifics. The number of small conspecifics eaten was related both to the absolute and relative densities of the alternative prey Pontoporeia affinis. The cannibalistic behaviour have the potential to act as a stabilizing mechanism in the Saduria-Pontoporeia system. Fourhom sculpin (Myoxocephalus quadricornis) was the fish species of utmost importance as a predator on S.entomon, and it mainly preferred large specimens. The amphipod Pontoporeia affinis matured at an age of two years in the littoral zone and at a very deep (210 m) locality. Between these depths it mainly reached maturation at an age of three years. In some years in densely populated areas, they delayed reproduction another year and reproduced as four year old. The variation in age at maturation in P.affinis in relation to depth could be quantitatively predicted by maximizing fitness in the Euler-Lotka equation. The size variation at maturation in S.entomon could be qualitatively predicted by maximizing fitness in the Euler-Lotka equation. The general condition for a smaller size at maturity to be adaptive at high temperatures (i.e. shallow areas) is that mortality rate should increase faster than growth rate with increasing temperature. When mortality is higher in young stages than in older and larger ones the pattern is also predicted when growth increases faster than mortality. Small animals may prefer warmer habitats than large ones, because of the presence of a size dependent trade-off between temperature induced growth and mortality. More exactly, the optimum solution of the trade-off between growth and mortality in hazardous environments was suggested to approach maximization of the expression s(W+g)/W, where s is survival rate, W is body weight, and g is growth rate. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1990, härtill 6 uppsatser</p> / digitalisering@umu
|
77 |
The effects of retrospectively examined early psychosocial stress on mate choice and sexual behaviour : a life history theory perspectiveKoehler, Nicole January 2007 (has links)
[Truncated abstract] Early psychosocial stress is conjectured to place individuals on a developmental trajectory leading to earlier pubertal maturation, earlier initiation of sexual activity and earlier reproduction than those with less early psychosocial stress. This may have an adaptive function to minimise the chances of lineage extinction, which is more likely in environments of high risk and uncertainty. Previous studies have examined the relationship between early psychosocial stress and life history stages (e.g., age at puberty, age at first sex and age at first birth). However, these studies are limited in that they either examined only a few early psychosocial stressors, examined psychosocial stress relatively late in individuals' lives and/or were restricted to women. Thus, the first aim of the present thesis was to examine these findings in both genders using a measure of early psychosocial stress comprised of 24 categories of retrospectively assessed stressors (e.g., sexual abuse, physical abuse, parental divorce, rated quality of family life) during the first 7 years of life. It was hypothesised that individuals with high, as opposed to low, levels of early psychosocial stress would pass through life history stages earlier. The second aim was to examine how early psychosocial stress affects characteristics associated with life history traits, such as individuals? length, number and type of heterosexual relationships, number of sex partners, adult attachment styles, number of pregnancy terminations, and attitudes and behaviours towards contraceptive use. High levels of early psychosocial stress were predicted to be associated with characteristics reflecting a quantitative, as opposed to a qualitative, reproductive approach (e.g., more sex partners, more short-term relationships, insecure attachment styles). The third aim was to examine how early psychosocial stress is related to mate choice because numerous studies have identified what traits individuals' desire in a mate but not whether early psychosocial stress affects these choices. ... Early psychosocial stress generally had no effects on age at first sex, age at first birth, the number of pregnancy terminations, and mate choices. On the other hand, individuals with high, as opposed to low, levels of early psychosocial stress were more likely to be insecurely attached, had more short-term sexual relationships (men only), had more extra-pair copulations, were more likely to be divorced/separated, had a greater lifetime number of sex partners (men only), and had lower self-rated frequencies of contraception use. Overall, some of these findings are consistent with life history theory, which suggests that individuals with high levels of early psychosocial stress (i.e., those living in environments of high risk and uncertainty) should reach biological maturation earlier, engage in behaviours that facilitate earlier and more frequent reproduction to minimise the chances of lineage extinction. Implications for public health, limitations of the present study and future directions are also discussed.
|
78 |
Metapopulations dynamics and sex-specific resource allocation in Silene dioicaPeedu, Elisabet January 2018 (has links)
Rising archipelagos provide unique settings for the study of the temporal and spatial dynamics of their biota. This offers the possibility to study the ecology and genetics of early successional processes; both between islands that differ in age and within islands when already established organisms have to keep pace with the changing environment. I have worked in the Skeppsvik Archipelago housing about 100 islands that due to land uplift vary in age, thus representing various stages of primary succession. I have utilized a naturally created metapopulation of Silene dioica, which in this archipelago is a dominant plant of the deciduous border, offering the possibility to study subpopulations on islands of different ages and in different phases of primary succession. Many plant species exist as metapopulations, which consists of many local populations which may differ in size and degree of connectivity. Metapopulations are further characterized by recurrent colorizations and extinctions of local populations, meaning that a species continually must disperse and relocate to allow for persistence in this system. For a dioecious plant species, gene flow is in the shape of seeds and pollen and to allow for the persistence of populations, it is necessary that levels of seed dispersal and pollen gene flow are enough to ensure both colonisation, establishment and subsequent population growth. Levels of seed dispersal and pollen gene flow is in turn influenced by how the two sexes partition resources between reproduction, growth and survival. In paper I, I combined a field survey, a common garden experiment and a nine-year demographic study to assess the demographic consequences of sex-specific resource allocation and to investigate if differential costs of reproduction may be a driver in the evolution of sexual dimorphism in dioecious Silene dioica. Significant somatic intersexual dimorphism was found with females being the larger sex, both in terms of above – and belowground biomass. Furthermore, the reproductive effort of females exceeds that of males across a growing season which largely confirms what has been observed earlier in dioecious, herbaceous plant species. According to the cost of reproduction hypothesis, high reproductive investment should result in trade-offs with somatic and/or life-history traits. Somatic trade-offs were not observed, and instead I found strong, positive associations between reproductive investment and vegetative growth in both males and females. Compensation mechanisms were found in both sexes although females are generally more efficient at compensating their reproductive costs. At the end of a flowering season, after having paid the current costs of reproduction, females are better than males at provisioning perennial roots and rosettes potentially influencing the ability to set future flower buds and winter survival. Trade-offs were found between current and future reproduction and survival, but this is condition dependent and compensation through frequency of flowering plays an important role. The cost of reproduction hypothesis appears to play some role in driving the somatic and demographic sexual dimorphisms observed in this system but sexual selection acting on males will be a fruitful avenue for future research. In paper II, I investigated the population genetic consequences of metapopulation dynamics in Silene dioica. The occurrence of islands in different phases of primary succession together with successional gradients across islands, makes it possible to investigate the genetic dynamics occurring in an age-structured metapopulation across several hierarchical levels. Genetic diversity and differentiation were estimated in eight young, recently colonised populations and in ten populations of an intermediate successional stage. Young populations were less genetically diverse compared to older populations, indicating that bottlenecks, created by small founding groups derived from a limited number of source populations, reduce the genetic diversity within newly founded populations. The observation of strong genetic structure both between islands and between patches with islands, indicates that gene flow is restricted across several spatial levels in this system. However, the lack of statistically significant differences in genetic differentiation between young and intermediate populations, indicates that levels of gene flow may not be high enough to reduce the genetic differentiation that arise from the initial founder event. The patterns of sexual dimorphism and the roles of males and females in Silene dioica have evolved to allow persistence in an ecological and population context of this species. The nature of this habitat, where islands rise up from the sea creating new environments for colonisation while at the same time, autogenic primary succession processes eventually leads to extinction, means that S. dioica continuously must relocate within successional phases for its persistence. The obvious success of this dioecious plant is apparent as it is one of the few dominant species in the deciduous border. This suggests that levels of seed dispersal and gene flow are sufficient enough to allow for establishment and persistence of island populations and that the sexual dimorphisms that have evolved in this metapopulation system act to increase levels of gene flow. The "live hard – die young" strategy, with extensive flowering bouts, which we find in the males may have evolved as a way of maintaining sufficient levels of genetic diversity in the metapopulation but will only be a possible strategy if there are continuous opportunities for re-establishments. Thus, the continuous land uplift that is occurring in the northern part of the Gulf of Bothnia may very well be a prerequisite for the long-term persistence of this dioecious, perennial plant species. / Landhöjningsprocesser i skärgårdsmiljöer skapar nya habitat som gör det möjligt att studera naturliga populationer i ett rumsligt och tidsmässigt sammanhang. Detta möjliggör studier av ekologi och genetik i tidiga successionsprocesser, både mellan öar som skiljer sig åt åldersmässigt och inom öar, där redan etablerade organismer måste anpassa sig till en föränderlig miljö. Jag har utfört studier i Skeppsviks skärgård som rymmer cirka 100 öar. På grund av landhöjningen så varierar dessa öar i ålder och de representerar således olika stadier i primärsuccession. Jag har använt mig av en naturlig Silene dioica metapopulation lokaliserad i Skeppsviks skärgård. Många växtarter existerar i metapopulationer, vilket består av ett antal lokala populationer som kan skilja sig åt i storlek och grad av anknytning. Metapopulationer kännetecknas även av återkommande koloniseringar och utrotningar av lokala populationer, vilket innebär att en art kontinuerligt måste sprida sig för att garantera sin fortlevnad i detta system. Genflöde inom dioika växtarter är i form av pollen och frön, och för att populationer skall kunna överleva så är det nödvändigt att nivåerna av fröspridning och pollen-genflöde är tillräckliga för att säkerhetsställa både kolonisering, etablering och efterföljande populationstillväxt. Nivåer av fröspridning och pollen-genflöde påverkas i sin tur av hur de två könen partitionerar resurser mellan reproduktion, tillväxt och överlevnad. I den första studien har jag kombinerat en fältundersökning, ett frilandsexperiment och en nioårig demografisk studie för att undersöka de demografiska konsekvenserna av könsspecifik resursallokering och för att utreda om könsspecifika skillnader i reproduktiv kostnad kan vara en drivkraft för evolutionen av sexuell dimorfism hos den dioika växten Silene dioica. Jag upptäckte signifikant somatisk intersexuell dimorfism där honor hade betydligt mer ovanjordisk och underjordisk biomassa jämfört med hanar. Över en växtsäsong så investerar honorna mer resurser i reproduktion, vilket i stor utsträckning bekräftar vad som tidigare har observerats i örtartade, dioika växter. Enligt hypotesen för reproduktiv kostnad så bör en hög investering i reproduktion leda till trade-offs med somatiska egenskaper, t.ex. tillväxt. Jag observerade inga somatiska trade-offs och istället fann jag positiva associationer mellan reproduktion och tillväxt hos både honor och hanar. Båda könen verkar ha utvecklat kompensationsmekanismer, även om honorna generellt är mer effektiva i hur de kompenserar för sina reproduktiva kostnader. Vid slutet av en växtsäsong, efter att ha betalat för de nuvarande reproduktiva investeringarna, så är honor bättre än hanar på att allokera resurser till fleråriga strukturer, såsom bladrosetter och rötter. Detta kan potentiellt påverka hur de anlägger sina knoppanlag för nästkommande år och hur väl de överlever vintern. Trade-offs hittades mellan nuvarande reproduktion och framtida reproduktionsmöjligheter och överlevnad men detta var habitat-specifikt och kompensation med hjälp av hur ofta en växt blommar under sin livstid spelar en viktig roll. Hypotesen för reproduktiv kostnad verkar vara en del av förklaringen till den somatiska och demografiska könsdimorfism som observerats i detta system men sexuell selektion, som verkar på hanar, kan vara ett möjligt område för framtida studier. I den andra studien undersökte jag populationsgenetiska konsekvenser av metapopulationsdynamik i Silene dioica. Förekomsten av öar i olika faser av primär succession tillsammans med olika grader av succession inom öar gör det möjligt att undersöka den genetiska dynamiken som uppträder i en åldersstrukturerad metapopulation över flera hierarkiska nivåer. Genetisk mångfald och differentiering uppskattades i åtta unga, nyligen koloniserade populationer och i tio populationer av ett intermediärt successionsstadium. Unga populationer hade lägre genetisk diversitet jämfört med äldre populationer, vilket indikerar att genetiska flaskhalsar, skapade av fåtal antal koloniserande individer, s.k. founders, som härrör från ett begränsat antal källpopulationer, minskar den genetiska diversiteten inom nybildade populationer. Observationen av stark genetisk strukturering, mellan och inom öar, indikerar att genflödet är begränsat över flera rumsliga nivåer i detta system. Bristen på statistiskt signifikanta skillnader i genetisk differentiering mellan unga och intermediära populationer indikerar emellertid att nivåer av genflöde kanske inte är tillräckligt höga för att minska den genetiska differentieringen som uppstår från den ursprungliga founder-händelsen. Mönstren av sexuell dimorfism och hanarnas och honornas roll har utvecklats för att möjliggöra fortlevnad i ett ekologisk och populationsmässigt sammanhang hos Silene dioica. I denna livsmiljö, där öar stiger upp ur havet och skapar nya miljöer för kolonisering samtidigt som autogena primära successionsprocesser leder till utrotning, måste S. dioica kontinuerligt sprida sig mellan olika successionsfaser för att överleva. Den uppenbara framgången för den här dioika växten är uppenbar eftersom den är en av de få dominerande arterna i lövkanten. Detta tyder på att nivåer av fröspridning och genflöde är tillräckliga för att möjliggöra etablering och beständighet av ö-populationer och att de sexuella dimorfismer som har utvecklats i detta metapopulationssystem verkar för att öka nivåerna av genflöde. "Lev hårt – dö ung" -strategin med omfattande blomningar som vi finner hos hanarna kan ha utvecklats som ett sätt att upprätthålla tillräckliga nivåer av genetisk diversitet i metapopulationen men den kommer endast att vara en möjlig strategi om det finns kontinuerliga möjligheter för re-etableringar. Således kan den kontinuerliga landupphöjningen som förekommer i norra delen av Bottniska viken mycket väl vara en förutsättning för den långsiktiga beständigheten av denna dioika, fleråriga växtart. / <p>Felaktigt angivet "Dissertation for PhD" i kolofon.</p>
|
79 |
A postcolonial critique of industrial design : a critical evaluation of the relationship of culture and hegemony to design practice and education since the late 20th centuryBegum, Taslima January 2015 (has links)
This thesis specifically focuses on the professional practices and training of Western industrial designers using postcolonial theory to inform working practices in a complex global ecology. It investigates the culturally hegemonic construction of design solutions in man-made products. By adopting key ideas from postcolonial and cultural studies as a lens to evaluate fields of industrial design discourse, practice and pedagogy, the work proceeds from the premise that design is not intrinsic to a product but the result of a myriad different forces and factors acting on it externally including hegemonic potencies. By reinterpreting technological formations in light of research emerging from post-colonial studies, it attempts to broaden our intellectual understanding of how product design in theory, practice and education can often rely upon western [hegemonic] aesthetic and deep cultural archetypes. The purpose of this enquiry is to highlight the potentials that exist to explore a synergy between east and west in industrial design with a prospective vision for global, trans-cultural design. The research claims that current design practice often leads to culturally determined - rather than universal - conceptions in design and it attempts to re-conceptualise design as practice within a necessarily hegemonic culture. This hegemony needs to be acknowledged and redressed via increased awareness and changes to the intellectual heritage and autonomy of West European and American industrial design, in its dialogue, practice and education. As an epistemological project to identify knowledge within this discourse, it suggests new methodological and strategic approaches to engage with the crisis the discipline faces in light of globalisation so as to open up future discussions in design discourse and give a voice to the many silences that make up the noise of the world. It attempts to: • Further understand the trajectory of hegemony and globalisation in relation to design, technology and culture. • Critically engage with cross- and trans-cultural, global and social design implications. • Address the discrepancies between designers’ culture and users’ culture, to expose the necessity for more culturally-cognizant design practice and pedagogic provision. The research was initiated by identifying a number of questions that designers and users may consciously or subconsciously confront when faced with products that problematise the imagined universal values of designed products in terms of gender and culture. It explores how certain design solutions produced and developed in the west and their diffusion into global, international markets and foreign cultures could affect those cultures by asking in what ways the usability, aesthetic and symbolic characteristics of these artefacts often unwittingly contribute to the privilege or marginalisation of people from particular socio-cultural backgrounds. The thesis intervention is that product designers are neither explicitly trained to comprehend nor surmount their respective cultural constraints and design education both nationally and internationally is not sufficiently equipped with the tools to acknowledge and confront this. The key arguments presented in this thesis are: 1. Products can often be deconstructed to identify cultural connotations or omissions in their design. 2. Global, a-cultural design and universal usability are fallacies that frequently deny the existence of an underlying cultural hegemony at play. 3. Mass-produced products can gradually homogenise and eradicate cultural diversity contributing to the negative effects of colonialist attitudes and/or globalisation. 4. Academia and educational institutions have the potential to extend awareness in this field to inform and train future designers and graduates to better advance design obligations in global, trans-cultural, cross-cultural and multicultural contexts.
|
80 |
Conflict between Saudi Arabia and Iran: An Examination of Critical Factors Inhibiting their Positive Roles in the Middle EastAlghunaim, Ghadah 01 January 2014 (has links)
Since 1979, Saudi-Iranian relations have been tense due to their position as superior powers in the Middle East. Both countries have different values and perspectives in regards to diplomatic relations with the West. As a consequence of the new developments in Iran's foreign policy and the newfound openness to the West adopted by President Rouhani, the topic has proven to be of research interest. The primary concern of this research was to explore the effect of the conflict between Saudi Arabia and Iran in the Middle East, and whether or not there is a possibility to overcome this conflict using the new political developments. For this purpose, a content analysis methodology was employed.
Through an analysis of data presented in the literature review, which consisted of scholarly articles, policy briefs, and books, this dissertation examines the complex political relations through which the pattern of the bilateral relations explain the conflicting narratives. This complexity is present in the political actions taken by Iran and Saudi Arabia, as well as the domestic and foreign policies they are embracing. The findings of this study demonstrate the effect of this conflict in the Middle East. The research also proposes a number of possible recommendations on how to resolve this conflict through political openness and reciprocal agreements that target the citizens of Iran and Saudi Arabia.
|
Page generated in 0.0749 seconds