Polar desert environments are limiting in plant available nutrients, mainly nitrogen (N) and phosphorus (P) that severely limit plant growth and establishment. Cryogenic activity regularly patterns the ground into a patchwork of frost boils – sorted circles that are associated with an increase in moisture, fertility and plant cover. Within some frost boils, the accumulation of ice-rich soil at the permafrost table can cause an upward flow of soil organic carbon (SOC) enriched permafrost material into the active layer. These diapiric intrusions are predicted to fuel microbial activity and enrich the horizon in N and P; however, the enrichment of the diapir horizon and accessibility by plants has yet to be studied. The aim of this research was to characterize the N distribution within diapir horizons located in frost boils and the effect of these intrusions on vascular plant N uptake in a polar desert ecosystem of the Canadian High Arctic. Natural abundance and enriched isotope 15N techniques were used to trace the flow of N through the soil-plant system. Surface and diapir horizons contained the highest total C and total N content within frost boils. Natural abundance δ15N analysis indicated that uptake by Salix arctica plants located on frost boils in the absence of a diapir horizon were sourcing N from the surface. However, when diapir nutrients became available, S. arctica plants began sourcing N from the diapir horizon and underlying low SOC sources in the soil, while reducing uptake from the surface. The altered foraging strategy of S. arctica in response to diapir horizon formation was further indicated by significant uptake of atom%15N nutrients that were injected directly into diapir horizons. These findings suggest diapir horizons are enriched in N and accessible by plants roots as an important nutrient source that is instrumental in their survival within frost boils of a polar desert ecosystem in the high arctic.

Swedes are extremely common as a root vegetable in Europe, USA, and Canada but are affected by the occasional presence of Brown Heart (BH) disorder affecting the marketable swede root. The incidence of BH has been reported worldwide however it is very difficult to breed resistance due to its sporadic occurrence with no external symptoms to select for. BH has been attributed to boron availability but attempts to link BH appearance definitively with boron deficiency have been difficult. Anecdotal evidence from breeders and growers highlighted the recent co-appearance of BH and frost injury in the field and it was postulated that if an association (physiological or genetic) can be determined between BH appearance and another more easily assessed trait such as frost susceptibility, then a frost tolerance screen may be developed as a useful surrogate method to screen for BH resistance. Frost hardiness assessment of 12 swede genotypes including some F1 hybrids was carried out. Results showed that some genotypes (like Ag31, Me77c and Or13) were more susceptible to frost (EL50 circa -7 ˚C) whilst others (like Gr19 and Ly01) were classified as more tolerant. Breeder trials data from the UK and Germany over a 10 year period showed that 85% of the BH incidence was associated with genotypes that had the frost susceptible lines Ag31, Or13 or Me77c in their parentage. To investigate this association further, frost susceptible and tolerant genotypes, together with a number of their F1 hybrids, were evaluated in a field trial for their response to boron treatments (0.00, 1.35, 1.80 and 2.70 kg B ha-1). At maturity, BH incidence and its severity was predominantly affected by genotype but could be ameliorated by boron application. Ag31 was confirmed to be the most susceptible to BH, and Or13 and Me77c were intermediate in their susceptibility. F1 hybrids between any two susceptible parents were also susceptible to BH. In contrast, genotypes Gr19 and Ly01 were confirmed to be highly resistant to BH and did not show any BH symptoms even at zero boron applied. F1 hybrids between resistant and susceptible lines demonstrated the BH resistant phenotype. Resistance to BH was therefore confirmed as a dominant trait with either a BHBH or BHbh genotype, whilst susceptibility was recessive bhbh. A degree of quantitative variation existed in the severity of the BH suggesting that BH resistance was not a single gene effect. BH severity was significantly negatively correlated (r = - 0.632) with root boron content in susceptible genotypes. The genotypes which were BH resistant in this trial were also more tolerant to frost in screening tests and this association was investigated further at a molecular level. Cold acclimation (CA) for 14 days at 4 ˚C positively affected the response of swede to frost, lowering the EL50 by -1.5˚C, and boron reduced the EL50 by -2.2˚C under non-acclimating conditions and by -1.2˚C under CA. Both boron and CA increased the catalase (CAT) and super oxidase dismutase (SOD) concentrations in swede leaves. Molecular analysis clearly demonstrated the presence of the B.napus cold response gene in swede, BN115, and was shown to be up-regulated due to both CA and boron application but differed between the two genotypes tested. The more frost resistant Gr19 showed a better response than the susceptible Ag31. Boron application reduced EL50 by -2.3˚C for Ag31 and -3.1˚C for Gr19. Given the association between frost tolerance and BH resistance it is suggested that a frost test screen could be used as a useful surrogate method to screen for BH resistance in swede breeding programmes.

Formalized epidemiological field investigations were conducted to compare and contrast the transmission dynamics of EHV-1 neurological disease among horses stabled at Churchill Downs Racetrack, Louisville, Kentucky and of EHV-1 respiratory illness among horses stabled in the student barn at Murray State University. Differences were assessed by means of statistical and mathematical modeling techniques applied to survey and biological data collected over the course of the respective disease events. Regression methods applied to survey data enabled the construction of a statistical model to predict a date of onset of illness for horses within each equine cohort. Comparisons of the epidemic curves revealed that the Murray State University outbreak was 4.5 times longer (9 weeks versus 14 days) than the Churchill Downs Racetrack event. Survival analysis was used to explore the relationship between time to infection for each equine cohort. Horses stabled in the affected barn at Churchill Downs racetrack had a 3.02 times greater daily risk (p < 0.001) for contracting EHV-1 infection relative to horses stabled in the student barn at Murray State University. Estimates of the basic R0 number, calculated using mathematical formulae that incorporated the duration of the infectious period for neuropathogenic and nonneuropathogenic strains of EHV-1, were 10.25 and 2.94 for the Churchill Downs racetrack and Murray State University outbreaks, respectively. The generation time for the Churchill Downs outbreak was 6.1 times shorter (0.39 days versus 2.38 days) than for the Murray State University event. An assessment of the temporal occurrence of symptomatic infection is similar for each event and suggests that the appearance of clinical illness is constant over the course of an outbreak. A Reed-Frost model was constructed for each EHV-1 event where values of the transmission parameters (q, p and k) were estimated by fitting a model that most closely matched the observed profile of EHV-1 cases. The value of prophylactic vaccination on the spread of EHV-1 was assessed by making adjustments to these fitted models for varying levels of herd immunity. The results indicate that the prevention of EHV-1 neurological illness requires a higher level of herd immunity than EHV-1 respiratory illness.

The sensitivity of Arizona-grown grapefruit to chilling temperatures varied throughout the harvest period studied. This sensitivity was high in October, decreased in November and December, then increased in February. In April and May there was another decrease in sensitivity to chilling temperatures. Coating fruit with vegetable oils or fats successfully delayed the development of chilling injury and reduced the degree of injury, however, vegetable oils applied as water emulsions were even more effective in preventing chilling injury to 'Redblush' grapefruit extending the period of marketability more than 100 days. Postharvest application of CaCl₂ and certain plant growth regulators significantly increased the resistance of 'Marsh' grapefruit to chilling injury, but less so than oil emulsions. Scanning electron microscope photomicrographs of 'Marsh' grapefruit peels showed that severe chilling injury was a depressed area of collapsed cell, just beneath the epidermis layer. As the severity of chilling injury increased, non-collapsed cells gradually increased in size. Cell walls were irregularly shaped; thin in some areas and thick in others. Oil glands in depressed areas were not ruptured during cold storage. Hence release of toxic materials through rupturing of oil glands is not a factor in chilling injury. Compared to non-injured tissue, injured tissue from the same fruits had significantly lower water and osmotic potentials, and low, near zero, turgor pressures. There was a significant negative correlation (r = -0.5; p < 0.05) between the water potentials of the peels and the percentage of 'Marsh' grapefruit with severe chilling injury during storage at 2.8C. Ion leakage tended to increase during cold storage, and when the fruit were transferred to room temperature. Internal conductivities declined sharply during cold storage and then increased very strongly during periods at room temperature.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Orientador: Davi Rodrigo Rossatto / Resumo: O Cerrado pode estar exposto a diversos distúrbios naturais moduladores, entre eles a geada. Este é um fenômeno capaz de afetar a distribuição e seleção de características de tolerância e sobrevivência das espécies nestas vegetações. Deste modo, o presente estudo pretendeu compreender os efeitos causados pela geada em espécies afetadas e não afetadas por este fenômeno, assim como quantificar características morfo-fisiológicas que possam explicar as respostas de rebrota a baixas temperaturas. As pesquisas foram realizadas em três locais distintos: em Águas de Santa Bárbara - SP na Estação Ecológica de Águas de Santa Bárbara – EecSB (acometida em 2016 por seis episódios de geada entre os meses de junho e agosto) (Capítulo I); Assis - SP na Estação Ecológica de Assis –EEA que foi acometida por eventos de geada no mesmo ano (Capítulo I e II) e na Reserva Ecológica do IBGE em Brasília – DF (Capítulo III). No segundo capítulo as coletas e experimentos foram realizados na EEA e no câmpus da Unesp. No capítulo I e II foram avaliados indivíduos de espécies previamente selecionadas após a ocorrência da geada, com o intuito de analisar os efeitos da mesma na mortalidade de indivíduos e ramos de espécies arbóreas consideradas como afetadas pelo fenômeno; também foi verificado se o espécime teve rebrote a partir do solo ou do caule/ramos e o grau de proteção das gemas, além disso, realizamos análises de respostas morfo-fisiológicas por meio da avaliação de atributos foliares, como, espess... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Cerrado can be exposed to several natural disturbances, being frost one of them. Frost is a phenomenon that can affect the distribution and selects tolerance and survival characteristics of species occurring in these vegetations. This study aimed to understand the effects caused by frost on the biomass of frost affected and non-affected tree species, and to quantify morpho-physiological characteristics that may explain the regrowth responses after the exposition to low temperatures. Data collection was carried out in three different locations: the first chapter was developed in Águas de Santa Bárbara- SP at the Ecological Station of Águas de Santa Bárbara – EecSB, which was affected in 2016 by six episodes of frost between the months of June and August; data for first and second chapter were collected in Assis – SP at the Ecological Station of Assis –EEA, which was also affected by frost events in the same year. The chapter III was conducted at the IBGE Ecological Reserve in Brasília – DF. In the chapter II the collections and experiments were carried out in Assis in the EEA and in Unesp campus. In chapter I and II, individuals from preselected species were evaluated to analyze the effects of frost on the branch mortality of tree species considered to be affected by the phenomenon; additionally it was verified whether the specimen had regrowth from the soil or the stem / branches and the degree of protection of the buds. We performed analyzes of morpho-physiological respo... (Complete abstract click electronic access below) / Mestre

<p>The dissertation takes as its starting-point the dichotomies between origin and modernity, periphery and centre. This is particularly the case in Astrid Väring’s novels Frosten (1926) and Vintermyren (1927), in which the author pays tribute to the homestead and the rural community in contrast to the industrial community, whilst her novels also express an ambivalent attitude towards modernity. Astrid Väring bases her works on a Norrland literary tradition, which often stood in opposition to the central power despite being dependent on it. In this respect, a similarity with postcolonialism is evident.</p><p>Access to a wealth of archive material, which has not previously been used in literary scholastic research, has resulted in a natural combination of a biographical method and socio-literary reading. When analysing the novels, the same external circumstances that had signifi cance for the author when the work was drafted, for example economic, social and political conditions, have therefore been taken into account.</p><p>With reference to the novel Katinka (1942), the view of popular literature during the 1940s is dealt with. The pejorative view, prevalent in those days, is compared with a contemporary understanding of it. Today, neither the canon nor popular literature stand out as particularly homogeneous categories. Katinka was written at the start of the Second World War. A comparison is made in the dissertation between Vilhelm Moberg’s Rid i natt! (Ride this Night) (1941) and Katinka in order to ascertain the novels’ attitude towards the offi cial Swedish position of neutrality. In Ride this Night rebellion against the enemy is encouraged, in Katinka a cautious, wait and see attitude is urged.</p><p>I som här inträden… (1944) is a novel with a purpose. In this novel Astrid Väring directs a harsh attack against the mental health care at Swedish mental hospitals. The dissertation contains a genre discussion concerning the various genres related to the novel with a purpose, for example roman à thèse. It can be concluded that theoretical work concerning the novel with a purpose is rare. But, when the issue pursued in the novel is no longer relevant, the novel with a purpose is often destined to be forgotten. Furthermore, Astrid Väring had the bad luck of falling in the shadow of Sara Lidman’s modernistic West-Bothnian accounts of the 1950s, which contributed to the fact that her entire works quickly fell into oblivion. This dissertation is the fi rst scholastic work on Astrid Väring’s works.</p>

The dissertation takes as its starting-point the dichotomies between origin and modernity, periphery and centre. This is particularly the case in Astrid Väring’s novels Frosten (1926) and Vintermyren (1927), in which the author pays tribute to the homestead and the rural community in contrast to the industrial community, whilst her novels also express an ambivalent attitude towards modernity. Astrid Väring bases her works on a Norrland literary tradition, which often stood in opposition to the central power despite being dependent on it. In this respect, a similarity with postcolonialism is evident. Access to a wealth of archive material, which has not previously been used in literary scholastic research, has resulted in a natural combination of a biographical method and socio-literary reading. When analysing the novels, the same external circumstances that had signifi cance for the author when the work was drafted, for example economic, social and political conditions, have therefore been taken into account. With reference to the novel Katinka (1942), the view of popular literature during the 1940s is dealt with. The pejorative view, prevalent in those days, is compared with a contemporary understanding of it. Today, neither the canon nor popular literature stand out as particularly homogeneous categories. Katinka was written at the start of the Second World War. A comparison is made in the dissertation between Vilhelm Moberg’s Rid i natt! (Ride this Night) (1941) and Katinka in order to ascertain the novels’ attitude towards the offi cial Swedish position of neutrality. In Ride this Night rebellion against the enemy is encouraged, in Katinka a cautious, wait and see attitude is urged. I som här inträden… (1944) is a novel with a purpose. In this novel Astrid Väring directs a harsh attack against the mental health care at Swedish mental hospitals. The dissertation contains a genre discussion concerning the various genres related to the novel with a purpose, for example roman à thèse. It can be concluded that theoretical work concerning the novel with a purpose is rare. But, when the issue pursued in the novel is no longer relevant, the novel with a purpose is often destined to be forgotten. Furthermore, Astrid Väring had the bad luck of falling in the shadow of Sara Lidman’s modernistic West-Bothnian accounts of the 1950s, which contributed to the fact that her entire works quickly fell into oblivion. This dissertation is the fi rst scholastic work on Astrid Väring’s works.

ABSTRACT Genial Thinking: Frost, Stevens, Ashbery by Andrew A. Klein This dissertation explores how Robert Frost, Wallace Stevens, and John Ashbery have responded to the problem of philosophical skepticism that they inherit from Emerson: that while things do in fact exist, direct knowledge of them is beyond our ken. Traditionally read within the framework of an evolving Romanticism that finds them attempting to resolve this problem through some form of synthesis or transcendence, I argue instead that these poets accept the intractability of the problem so as to develop forms of thinking from within its conditions. Chapter One explains why poetry is particularly suited to this sort of thinking and what it can achieve that philosophy (or at least a certain understanding of it) cannot. Chapter Two focuses on the act of listening in Stevens’s poetry as a way to show how Stevens is not, as is typically thought, interested in “the thing itself,” but in "the less legible meaning of sounds," the slight, keen indecision that resonates in between sense and understanding. Chapter Three focuses on those moments in Frost’s poetry when, instead of attempting to comprehend, seize, grasp, and represent reality through the use of metaphor, he chooses to regard its inappropriability or otherness. And Chapter Four focuses on how Ashbery’s constant shifts of focus are not just the wanderings of his mind, but a technique for disrupting our absorption in a single plane of attention so as to achieve new economies of engagement. Overall, though, the goal of this project is to move the discussion about this line of poets out of the epistemological register within which they are usually read and into an ethical one.

A major challenge to cold regions hydrology and northern water resources management lies in predicting runoff dynamically in the context of warming-induced changes to the rates and patterns of ground thaw and drainage. Meeting this challenge requires new knowledge of the mechanisms and rates of ground thaw and their implications to water drainage and storage patterns and processes. The study carries out to evaluate the concept of energy-based runoff in the perspective of ground heat flux, soil thaw and liquid moisture content, tortuosity of snow-free area, preferential flow and discharge of the hillslope. Based on field measurements, coupled energy and water flow is simulated in the Area of Interest (AOI) with a half-hour time interval by the distributed hydrological model, GEOtop. In the field, the saturated hydraulic conductivity varies exponentially between the superficial organic layer and the underlying mineral layer. In the simulation, the parameters of the soil physical properties are input by fourteen uneven layers below the ground surface. Starting from the initially frozen state, the process of soil thaw is simulated with dynamic variables such as soil liquid moisture and ice content, hydraulic conductivity, thermal conductivity and heat capacity. The simulated frost table depths are validated by 44-point measurements and the simulation of point soil temperature is also compared to data measured in an excavated soil pit. As a result, the frost table topography is dominated by both the snow-free pattern and the energy fluxes on the ground surface. The rate and magnitude of runoff derived from snow drift and the ice content of frozen soil is greatly influenced by the frost table topography. According to the simulation, the frost table depth is closely regressed with the ground surface temperature by a power function. As soil thawing progresses, ground heat flux reduces gradually and the rate of soil thaw becomes small when the frost table descends. Along with the snow-free area expanding, the average soil moisture of the AOI increases prior to that time when the average frost table is less than 25 cm deep. The snow-free patches expand heterogeneously in the AOI, which causes the spatial and temporal variation of hydraulic conductivity due to the non-uniform frost table depth. According to the simulation, the transit time of the flow through the AOI decreases to the shortest span on May 13 with the average frost table of 10 cm. Before this date, the time lag between snowmelt percolation and slope runoff is about 8-10 hours; while after this date, the time lag is no more than 5 hours. The pattern of the preferential flow in the AOI highly depends on the frost table topography. When the snow-free patches are widely scattered and the average frost table is between 0 and 10 cm, the preferential flow paths are inhibited. With soil thaw progresses, the preferential flow paths are prominent with the largest single contributing area occurring when the average frost table is between 10 cm to 15 cm. When the average frost table reaches 25 cm, the importance of preferential flow is not apparent, and matrix flow prevails.