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<p> Natural peatlands are an important component of the global carbon cycle representing a net long-term sink of atmospheric carbon dioxide (CO2). The natural carbon storage function of these ecosystems can be severely impacted due to peatland drainage and peat extraction leading to large and persistent sources of atmospheric CO2 following peat extraction abandonment. Moreover, the cutover peatland has a low and variable water table position and high soil-water tension at the surface which creates harsh ecological and microclimatic conditions for vegetation reestablishment, particularly peat-forming Sphagnum moss. Standard restoration techniques aim to restore the peatland to a carbon accumulating system through various water management techniques to improve hydrological conditions and by reintroducing Sphagnum at the surface. However, restoring the hydrology of peatlands can be expensive due to the cost of implementing the various restoration techniques. The goal of this study is to examine a new extraction-restoration technique where the acrotelm is preserved and replaced on the cutover surface. More specifically, this thesis examines the effects of an acrotelm transplant experiment on the hydrology (i.e. water table, soil moisture and soil-water tension) and peatland-atmosphere CO2 exchange at a cutover peatland.</p> <p> The experimental acrotelm restoration technique maintained both high water table and moisture conditions providing sufficient water at the surface for Sphagnum moss. Furthermore, the high moisture conditions and low soil-water tensions compared to an adjacent natural site were maintained well above the measured critical Sphagnum threshold of 33% (-100 mb) VMC further providing favourable conditions for Sphagnum moss survival and growth.</p> <p> Peat respiration at the experimental restored acrotelm (110.5 g C m-2) was considerably lower than the natural peatland (144.8 and 203.7 g C m-2). However, gross ecosystem production (GEP) at the experimental site (-54.0 and -34.4 g C m-2) was significantly reduced compared to the natural site (-179.2 and -162.0 g C m-2). Consequently this resulted in a shift towards a net source of CO2 to the atmosphere over the season at the experimental site (78.5 and 56.5 g C m-2) and a sink of CO2 at the natural site (-17.6 and -22.8 g C m-2).</p> <p> Light response curves indicated that maximum GEP was considerably lower at the experimental site; however it is likely that the percentage of living and dead vegetation at the plots post restoration had a large control on this lower productivity as plots with more living vegetation had higher overall productivity (GEP). Despite wetter conditions at the experimental site, large diurnal variations in moisture (~30%) were observed suggesting disturbance to the peat structure. Although soil-water retention analysis and physical peat properties indicated that no apparent structural change in peat structure occurred, it is theorized that a change in volume in the capitula may enhance the wetting and drying cycles in moisture. Lateral expansion/contraction within the peat matrix may occur due to spaces (gaps/fissures) left between the replaced acrotelm blocks from the extraction-restoration process promoting large changes in moisture which consequently can affect the gas exchange process at the surface. Large changes in peat and capitual moisture have been shown to affect productivity leading to variable GEP and enhanced respiration, making it important to limit the moisture variability at the surface from a carbon cycling perspective. Therefore it is likely that a combination of both physiological health of the vegetation and wetting/drying cycles contributed to lower GEP, suggesting the importance of limiting disturbance at the surface during the extraction and restoration process.</p> <p> The new extraction-restoration technique has potential to return a peatland to both near-natural hydrological conditions and towards a net sink of atmospheric CO2. The replaced acrotelm on the cutover surface aided in maintaining adequate moisture conditions thereby provided adequate conditions for Sphagnum survival and reestablishment. However, the ability of the system to remain a net sink of CO2 as like the natural site was not observed post-disturbance due to differences in productivity. Nevertheless, the experimental site did maintain limited productivity post-extraction indicating that the carbon dynamics of the system was maintained due to this acrotelm restoration process potentially returning the ecosystem towards a natural sink of atmospheric CO2 over a longer period time.</p> / Thesis / Master of Science (MSc)

Water conservation and pollution concerns from nutrient runoff will very likely dictate precise irrigation regimes for nursery managers in Virginia. Maximum plant growth with minimum input of water and fertilizer is becoming increasingly important. Therefore, water use and growth of red and sugar maple (Acer rubrum L. 'Franksred' and Acer saccharum Marsh.) were studied during two years of pot-in-pot (P+P) production and during three years after transplanting to field soil. Three major experiments were completed. The first experiment studied the effect of frequent irrigation (three-times-a-day) versus standard once-a-day irrigation and found that frequent irrigation increased trunk diameter growth of sugar maples in the second production cycle and for red maples in both production cycles. Height growth of neither species was affected by frequent irrigation. A study of sap flow pattern indicated that late day water stress of red maples was partially alleviated by frequent irrigation. In the second experiment, red and sugar maples were transplanted to field soil after one (1-yr) or two (2-yr) years of P+P production. Irrigation frequency requirement decreased as the trees grew and depended on environmental conditions, size at planting, source of water (rainfall versus irrigation) and species. Height and trunk diameter of 1-yr red maple was equal to that of 2-yr trees after only one year. Height and trunk diameter differences between 1-yr and 2-yr sugar maple trees persisted three years after transplanting. In the third experiment water use of 1-yr and 2-yr red and sugar maple while in P+P production was investigated. Four models of daily water-use were developed. A simple model that is suitable for growers includes species, trunk cross-sectional area (BA) and air temperature (TA) observations. An environmental model was developed using the Penman-van Bavel estimate of evapotranspiration (ET). ET required modifications based on tree characteristics, air temperature, windspeed and relative humidity to be an effective predictor of water-use. A complex model was based on a sine-cosine function of day-of-the-year. This model fits water-use data well for each species and production cycle and includes BA, ET and TA. An alternate simpler model requires only day-of-the-year, TA and BA, offering growers a relatively simple and accurate model of water use. / Ph. D.

All species on Earth occupy limited geographic space. More than a century of observational, experimental, and theoretical work investigating the factors that drive species distributions have demonstrated the importance of the interactions between abiotic, biotic, and demographic factors in determining why species are found where they are. However, it is still unclear when and where these factors interact to set species range limits. Filling the existing knowledge gaps is imperative for the accurate predictions of how species will respond to global change, and particularly for invasive species, many of which are expected to benefit from global change. Here, I sought to investigate the mechanisms that enable, as well as limit, the range expansion of the globally invasive plant Sorghum halepense (L.) Pers. (Johnsongrass). I performed a series of field and laboratory experiments to study population and range dynamics throughout Johnsongrass's North American distribution, and test for the effects of climate, local habitat, and competition on multiple functional traits. I found Johnsongrass consistently demonstrated impressive performance across varying environments, often growing more than 3 m tall, producing hundreds of flowering culms within a single growing season, and maintaining positive population growth rates, even under intense competition with resident weeds. I also found evidence that seed germination has adapted to varying climates encountered during Johnsongrass's range expansion resulting in a shift in the germination temperature niche from warmer to cooler as Johnsongrass spread from warmer climates in the south to more temperate climates in higher latitudes. This shift in the germination temperature niche may have been an important contributing factor in the range expansion of Johnsongrass by enabling the optimization of seed germination in varying climates. On the other hand, results from a field study suggested a possible trade-off between flowering time and growth in populations originating from the range periphery (i.e., range boundary) which may be limiting, or slowing, continued range expansion of Johnsongrass. Together, the outcomes of this work contribute to our understanding of the factors involved in the distribution of species, which is a fundamental goal of Ecology, and essential to accurately predict how invasive species will respond to global change. / Doctor of Philosophy / Invasive species threaten our natural ecosystems, our agricultural systems, and even our infrastructure, and we spend billions of dollars each year attempting to control them and reduce their negative impacts. Climate change, habitat destruction, and other forms of global change, will benefit many of these species, magnifying their impacts and promoting their invasion into new territories. Because of the damaging effects of invasive species, and the costs to control them, it is imperative that we are able to predict how they will respond to global change so that we can improve plans to reduce their impact and spread. First, we need to understand the processes that promote their invasion across large swaths of land. Just as importantly, we must study the processes that prevent their invasion of certain areas. Here, I investigated some of the processes that have facilitated, as well as hampered, the spread of the invasive plant Johnsongrass. For this work, I used Johnsongrass plants originating from different habitats, including regions where Johnsongrass is highly invasive and those where Johnsongrass is very rare. I found Johnsongrass originating from regions where it is highly invasive were able to grow very large and produce thousands of seeds that were able to germinate under a range of conditions. These traits may have contributed to the invasion success of this species. However, I found a different pattern for plants that originated from regions where Johnsongrass is rare. These plants reached reproductive age earlier and grew smaller across all environmental conditions, potentially due to the less hospitable climates of these range edges. These findings allow us to project into future climate change scenarios, because it is likely that, as temperatures warm, invasive species will be able to invade new regions, where they will impact the work of conservationists, natural resource professionals, agricultural produces, and other land managers.

A doença hepática terminal reduz de forma significativa a qualidade de vida de pacientes e com o transplante do órgão é possível melhorar as condições de saúde. A sexualidade é aspecto central do ser humano durante todo o ciclo vital. É área complexa do comportamento humano, assim a sexualidade de candidatos e receptores de transplante de fígado não deve ser menosprezada. O presente estudo teve como objetivo analisar as evidências disponíveis na literatura sobre as alterações na sexualidade de candidatos e receptores de transplante de fígado. Trata-se de revisão integrativa da literatura: as bases de dados selecionadas para a busca dos estudos primários foram PubMed, CINAHL e LILACS. Os 16 estudos primários incluídos na revisão foram agrupados em três categorias: (1) sexualidade feminina (n=5); (2) sexualidade masculina (n=5) e; (3) sexualidade masculina e feminina (n=6). Na categoria 1, os principais temas de investigação foram contracepção, gravidez, disfunção sexual, presença de sintomas ginecológicos e doença sexualmente transmissível. Na categoria 2, o foco principal dos estudos primários agrupados foi a disfunção erétil e investigou-se também desejo/satisfação sexual e as consequências de homens que tiveram filhos, em regime imunossupressor com ácido mycofenólico. Na categoria 3, a avaliação da função sexual foi o principal tema abordado nas pesquisas analisadas. A sexualidade é problemática desafiadora, revestida por tabus e preconceitos, vivenciada de forma diferente pelos indivíduos. Assim, os pacientes podem apresentar dificuldades em relatar para os profissionais da saúde seus problemas, acarretando atraso do diagnóstico e tratamento, prolongando a sensação de desconforto e sentimento de angústia. A dificuldade em abordar sobre sexualidade também ocorre por parte dos profissionais de saúde que não recebem capacitação adequada. O conhecimento sobre as dúvidas e problemas vivenciados pelos candidatos e receptores de transplante de fígado pode proporcionar a implementação de intervenções direcionadas para prevenção, redução ou controle das complicações no período pré e pós-transplante. O presente estudo forneceu subsídios para encorajar os profissionais de saúde a incorporar a sexualidade na rotina de atendimento destes pacientes, bem como indicou lacunas no conhecimento para a condução de novas pesquisas com o propósito de implementar intervenções na pratica clínica para prevenir, minimizar e/ou controlar as alterações relacionadas à sexualidade do paciente, contribuindo para a melhoria da assistência de enfermagem e, consequentemente, para o sucesso do tratamento / The end-stage liver disease significantly reduces the quality of life of patients. However, with organ transplantation it is possible to improve health conditions. Sexuality is a central aspect of the human being throughout the life cycle. It is a complex area of the human behavior and therefore the sexuality of liver transplant candidates and recipients should not be overlooked. The present study aimed to analyze the evidence available in the literature on the changes in the sexuality of candidates and recipients of liver transplant. This is an integrative literature review, and the databases selected for the search of the primary studies were PubMed, CINAHL and LILACS. The 16 primary studies included in the review were grouped into three categories: (1) female sexuality (n = 5), (2) male sexuality (n = 5) and (3) male and female sexuality (n = 6). In category 1, the main research topics were contraception, pregnancy, sexual dysfunction, presence of gynecological symptoms and sexually transmitted disease. In category 2, the focus of the primary studies grouped was erectile dysfunction, it was also investigated the sexual desire/satisfaction, and the consequences of men who had children under immunosuppressive regimen with mycophenolic acid. In category 3, the evaluation of sexual function was the main topic addressed in the studies analyzed. Sexuality is a challenging problem, enrobed with taboos and prejudices, and experienced differently by individuals. Thus, patients may present difficulties in reporting their problems to health professionals, leading to delays in diagnosis and treatment, prolonging feelings of discomfort and distress. The difficulty in addressing sexuality also occurs on the part of health professionals who do not receive adequate training. Knowledge about the doubts and problems experienced by candidates and recipients of liver transplant can facilitate the implementation of interventions aimed at prevention, reduction or control of complications in the pre- and post-transplantation period. The present study provided subsidies to encourage health professionals to incorporate sexuality in the care routine of these patients, it also indicated gaps in knowledge for the conduct of new research with the purpose of implementing interventions in clinical practice to prevent, minimize and/or to control the changes related to the patient\'s sexuality, contributing to the improvement of nursing care and, consequently, to the success of the treatment

Além de modular o metabolismo energético, o tecido adiposo constitui um regulador endócrino, produzindo fatores como a adiponectina (APN), adipocina pouco expressa na obesidade, com propriedades imunoreguladoras. Neste trabalho investigamos o papel da obesidade e APN em modelos murinho de transplante de pele e doença do enxerto-versus-hospedeiro (GvHD), na obesidade induzida por dieta hiperlipídica (Ob) e animais knockout (KO) para APN. Em suma, receptores Ob e APN KO apresentaram rejeição acelerada de enxerto de pele, associado inflamação do tipo Th1 e Th17. A obesidade também levou a pior GvHD, associado a maior inflamação no fígado, pulmão, intestino junto a dano hepático e intestinal, enquanto a manutenção de dieta HF após o transplante preveniu parciamente este dano. Estudos in vitro corroboraram estes resultados, mostrando maior ativação dendrítica e linfocitária em meio mimetizando a obesidade. Desta forma, este estudo sugere que a obesidade e redução de APN levam a maior rejeição de transplantes sugerindo adiante um papel importante à dieta neste processo. / In addition to modulating energy metabolism, the adipose tissue is an endocrine regulator, producing factors such as adiponectin (APN), an adipokine little in obesity, with immunoregulatory properties. In this work we investigated the role of obesity and APN in skin transplant and graft-versus-host disease (GvHD) in high-fat diet induced obesity (Ob) and knockout (KO) mice for APN. In summary, Ob and APN KO receptors showed accelerated skin graft rejection, associated with Th1 and Th17 type inflammation. Obesity also led to worse GvHD, associated with increased inflammation in liver, lung, intestines along with liver and gut damage, while maintenance of the HF diet after transplantation partially prevented this damage. In vitro studies corroborated these results, showing greater dendritic and lymphocytic activation in conditions mimicking obesity. Thus, this study suggests that obesity and reduced APN lead to greater rejection of transplants further suggesting an important role of diet in this process.

Esta pesquisa teve como objetivo conhecer a percepção de familiares de potenciais doadores sobre os motivos considerados para recusar a doação dos órgãos e tecidos para transplante. Para compreender a percepção dos familiares optou-se por realizar uma pesquisa qualitativa, segundo a modalidade \"estrutura do fenômeno situado\". Como forma de desvelar o fenômeno foram entrevistadas oito famílias, utilizando as seguintes questões norteadoras: \"Como foi a tomada de decisão para recusar a doação dos órgãos e tecidos para transplante do seu familiar falecido?\" e \"Quais os motivos considerados para recusar a doação?\". Após a obtenção das descrições, os discursos foram analisados individualmente, sendo feita a análise ideográfica, resgatando os seguintes temas e subtemas: \"Relatando a internação do familiar\", \"Vivenciando a perda do familiar\": \"Recebendo a informação da morte encefálica e a solicitação da doação\", \"Sofrendo com a perda do familiar\"; \"Decidindo pela recusa da doação dos órgãos\": \"Conversando sobre doação\", \"Respeitando a decisão tomada\"; \"Apresentando os motivos de recusa da doação dos órgãos\": \"A crença religiosa\", \"A espera de um milagre\", \"A não compreensão do diagnóstico de morte encefálica e a crença na reversão do quadro\", \"A não aceitação da manipulação do corpo\", \"O medo da reação da família\", \"A inadequação da informação e a ausência de confirmação da morte encefálica\", \"A desconfiança na assistência e o medo do comércio de órgãos\", \"A inadequação no processo de doação\", \"O desejo do paciente falecido, manifestado em vida, de não ser um doador de órgãos\" e \"O medo da perda do ente querido\". Buscou-se desvelar, pela análise nomotética, as convergências e divergências das unidades de significado interpretadas, em direção a estrutural geral do fenômeno. As proposições que emergiram revelaram que a essência do fenômeno \"A recusa familiar no processo de doação de órgãos e tecidos para transplante\" foi desvelada como vivenciar uma situação de choque e desespero com a internação do familiar, de desconfiança com a solicitação da doação dos órgãos, de negação da morte encefálica, de sofrimento e desgaste diante da perda do ente querido, de conflitos familiares para a tomada de decisão e de múltiplas causas para a recusa da doação / This research had as its target learn the perception of potential donator`s familiy on the considered reason for the organs and tissues donation refusal for transplant. In order to understand the family perception a qualitative research was chosen, according to the modality \"situated phenomena structure\". In way of unveil the phenomena eight families were interviewed, having these questions as a guide:\"How was the decision taken in order to refuse the organs and tissues donation for tranplant of your deceased next of kin?\" and \"Which are the reasons weight for the donation refuse?\". After getting the descriptions, the speech were individually analysed, where a ideographic analysis was taken, recovering the folowing themes and sub themes : \"Telling next of kin as in patient\", \"Witness the next of kin\'s loss\": \"Receiving the encephalic death information and the solicitation for donation\", \"Suffering the next of kin\'s loss\"; \"Taken the organs and tissues donation refuse\": \"Talking about donation\", \"Regarding the taken decision\"; \"Presenting the refusal organs and tissues donation reasons\": \"The religious belief \", \"A hope of miracle\" , \"The encephalic death diagnosis missuderstood and the believe of a reversion of the situation\", \"Disagreement on the body maneuver\", \"The worry of the family\'s reaction\", The information ineffectuality and the lack of the encephalic death confirmation\",. \"The assistance mistrust and the fear of organs market\", \"The deficiency of donation process\", \"The person\'s willing not to be an organ donator when alive\" and \"The fear of loosing the dearest next of kin\". Through out of the nomothetic analysis, the meaningfull units convergency and divergency been taken, directed to the general structure phenomena. The propositions which appeared shown that the phenomena essence \"The family refusal on the organs and tissues donation for transplant\" was unveiled as been trought a shock situation and disperation with the next of kin in patient situation, mistrust because of the organs and tissue donation requesting, the denying of encephalic death, suffering and exhausting before the loss of the beloved one, family conflicts in way of taken the decision and the multiple causes of organ and tissues donation refuse