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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Aspect induced differences in vegetation and soil on north- and south-facing slopes in western Massachusetts /

Enters, Dirk 01 January 1999 (has links) (PDF)
No description available.
102

The Energy Benefits of Trees: Investigating Shading, Microclimate and Wind Shielding Effects in Worcester and Springfield, Massachusetts

Morzuch, Emma L. 01 January 2013 (has links) (PDF)
Most scientific studies concerning energy conservation benefits of trees have been completed in cooling dominated climates or have involved model-based engineering studies. An infestation of the Asian Longhorned Beetle (ALB) (anoplophora glabripennis) has initiated an extensive tree removal program in Worcester, Massachusetts. A June 1, 2011 tornado in Springfield, Massachusetts has damaged a randomized sample of the urban canopy cover in Springfield. These events provide natural, controlled experiments to quantify the energy use impact of trees in real-world settings. Large-scale tree removal and natural disasters completely transform the landscape. Due to the reduction in shade, near-ground temperature increase is substantial. With the trees gone, the increased velocity of cold winter winds is noticeable for neighborhood residents. Tree removal due to ALB infestation in two residential neighborhoods in Worcester, Massachusetts in the winter of 2008-2009 resulted in a 37% increase (t = -9.09, p<0.001) in baseline-corrected, weather-normalized electrical consumption from the 2008 to 2009 cooling seasons. In Springfield, Massachusetts we find no difference in baseline-corrected, weather-normalized natural gas consumption for the heating season for individual homes after the June 1, 2011 tornado. The results of this research will aid in the development and implementation of energy conserving treeplanting and retention programs and policies pursuant to the Clean Energy and Climate Change Plan of 2010 in Massachusetts.
103

Evaluation of heat abatement use, vaginal temperature, and activity of pregnant, lactating Holstein cows housed on pasture with or without the choice between shade and sprinklers for heat abatement.

Braman, Kevin M. 08 August 2023 (has links) (PDF)
The objective of this thesis was to determine how pregnant, lactating Holstein cows on pasture interact with shade and sprinklers when offered a choice or no-choice between methods. Authors hypothesized that cows would use shade more then sprinklers, but sprinklers would be more effective at cooling cows. Additionally, authors predicted cows using shade more would have decreased lying bouts and steps and an increase in time lying, compared to cows choosing sprinkler. Results indicate cows will use both methods when offered alone or together. However, cows will choose to be exposed or in shade at lower temperature humidity index values, but as the heat load increases, cows will shift to using sprinkler just as much as shade, and decrease overall time exposed. Overall, sprinklers were more effective at reducing vaginal temperature in heat stressed cows on pasture. Cows in shade had decreased lying bouts and steps, and increased time lying.
104

SHADING ANALYSIS OF AGRIVOLTAIC SYSTEMS : The shading’s effect on lettuce and potato from elevated agrivoltaic system in Sweden

Farid, Komail, Guleed, Ahmad January 2023 (has links)
The world is progressing towards a more sustainable society, where renewable energy sources, including solar energy, play a crucial role. This study aims to address the conflict between agriculture and energy production by exploring the installation of solar panels on farmland. Four scenarios are considered, with varying parameters such as latitude, azimuth, slope, and row distance between photovoltaic (PV) modules. The study focuses on two different crops, lettuce and potato, which have varying tolerances to shading. The objective is to understand how the shadows cast by solar panels affect the growth of these crops. To analyze the impact of shading, the PVsyst software program is utilized to obtain PAR values for each scenario. The calculations are performed using Excel equations. The literature review encompasses scientific sources that provide insights into both PV technology and agriculture, bolstering the research findings. To ensure realism and manage simulation time, certain delimitations were made. These include limiting the study to two cities in Sweden, comparing only two crops, and conducting simulations during the summer period. The results reveal a significant potential for growing potatoes under PV modules. However, lettuce faces difficulties due to its high requirement for solar intensity (PAR), making it less adaptable to shade. The findings of this study indicate that crops like potatoes, which have a lower requirement for PAR, can be successfully cultivated in conjunction with photovoltaic (PV) systems. However, it is not advisable to implement AV systems in areas where sensitive crops like lettuce, which necessitate a significant number of sun hours with high solar intensity.
105

Future climate suitability of shade trees in cocoa agroforestry systems in West Africa and shade tree diversity’s impact on farm microclimate : A Minor Field Study / Framtida klimatlämplighet för skuggträd i kakaoskogslantbruk i Västafrika och påverkan på gårdars mikroklimat av skuggträdens diversitet : En Minor Field Study

Halonen, Jonna January 2023 (has links)
Shade trees’ implementation into cocoa agroforestry systems in tropical West Africa has proven to have a high potential in increasing farm resilience and mitigating climate change. However, no studies have yet examined the potential future climate suitability for shade trees in the region, which is important when deciding which shade trees to implement. The aim of this study was to predict the current and future climate suitability of shade trees currently used in cocoa agroforestry systems and give recommendations based on the results. It also aimed to examine how different levels of shadetree diversity can impact a farm’s microclimate and how this can be linked to climate suitability for cocoa. To assess climate suitability, a species distribution model was performed for a baseline scenario with the current climate defined as 1970-2000 and for two future scenarios, SSP126 and SSP585, for the time period 2041-2060. To measure microclimate, a microclimatic study was performed in the Ashanti region of Ghana on 16 farms during mid March to mid May 2023 measuring the maximum temperature above cocoa canopy and 15 cm above the ground for three different treatments. The results showed that three species, Khaya senegalensis, Ceiba pentandra and Albiziazygia, were predicted to have the largest habitat areas of climate suitability in West Africa for several of the scenarios. However, it was also identified that the model could be improved when it comes tothe inclusion of more bioclimatic variables, global circulation models (GCMs) and for which futures cenarios to model for. The microclimatic study showed that both farms with a low and high level of shade tree diversity have a significant possibility to buffer the maximum temperature above cocoa canopy, with low diversity farms having a larger buffering capacity. The study also showed that areaswhere several shade tree species are predicted to have a climatically suitable habitat decreased for future scenarios, which could be a risk for the possibility to mitigate climate change for cocoa with shade tree implementation in the future. / Att implementera skuggträd i kakaoskogslantbruk i tropiska Västafrika har visat sig ha en högpotential att öka resiliens på gårdar såväl som att motverka effekterna av klimatförändringar iregionen. Däremot har inga tidigare studier hittills undersökt vilka skuggträdsarter som väntas varalämpliga i framtida klimat. Syftet med den här studien var att uppskatta nutida och framtidalämplighet för skuggträd som nu används i kakaoskogslantbruk och ge rekommendationer utifrånresultaten. Studien hade också som syfte att undersöka hur olika nivåer av diversitet av skuggträd på gårdarna påverkade deras mikroklimat samt hur detta kan kopplas till klimatlämplighet för kakao. Klimatlämplighet uppskattades med en distributionsmodell (eng: “species distribution model”), med ett basscenario för nutida klimat satt som 1970-2000 samt med två framtida klimatscenarier, SSP126 och SSP585, för tidsperioden 2041-2060. Mikroklimat mättes genom en fältstudie som genomfördes på 16 gårdar i Ashantiregionen i Ghana under perioden mitten av mars till mitten av maj. Mikroklimatet mättes för den maximalt uppnådda temperaturen ovanför kakaoträdens lövverk och 15 cm ovanför marken. Resultaten visade att tre arter, Khaya senegalensis, Ceiba pentandra och Albiziazygia, hade störst område där de var lämpliga för flest klimatscenarier i Västafrika. Dessutom identifierades flera sätt att förbättra modellen, bland annat genom att inkludera fler bioklimatiska variabler, fler globala cirkulationsmodeller (GCMs) och genom att förutspå utvecklingen för fler framtida klimatscenarier. För mikroklimat visade resultaten att både en hög och låg diversitet av skuggträd resulterade i att den maximala temperaturen minskade ovanför skuggträdens lövverk, och den minskade mer där diversiteten var låg. Resultaten visade även att för framtida klimatscenarier minskar områdena där flera skuggträd är lämpliga, vilket kan vara problematiskt för möjligheten att bemöta klimatförändringar i framtiden genom skuggträdsimplementering.
106

Chemical and Geological Controls on the Composition of Waters and Sediments in Streams Located within the Western Allegheny Plateau: The Shade River Watershed

Gbolo, Prosper 29 July 2008 (has links)
No description available.
107

INVESTIGATING THE FUNCTIONAL ROLE OF MED5 AND CDK8 IN ARABIDOPSIS MEDIATOR COMPLEX

Xiangying Mao (6714896) 02 August 2019 (has links)
<p>The Mediator (Med) complex comprises about 30 subunits and is a transcriptional co-regulator in eukaryotic systems. The core Mediator complex, consisting of the head, middle and tail modules, functions as a bridge between transcription factors and basal transcription machinery, whereas the CDK8 kinase module can attenuate Mediator’s ability to function as either a co-activator or co-repressor. Many Arabidopsis Mediator subunit has been functionally characterized, which reveals critical roles of Mediator in many aspects of plant growth and development, responses to biotic and abiotic stimuli, and metabolic homeostasis. Traditional genetic and biochemical approaches laid the foundation for our understanding of Mediator function, but recent transcriptomic and metabolomic studies have provided deeper insights into how specific subunits cooperate in the regulation of plant metabolism. In Chapter 1, we highlight recent developments in the investigation of Mediator and plant metabolism, with emphasis on the large-scale biology studies of <i>med</i> mutants.</p> <p>We previously found that MED5, an Arabidopsis Mediator tail subunit, is required for maintaining phenylpropanoid homeostasis. A semi-dominant mutation (<i>reduced epidermal fluorescence 4-3</i>, <i>ref4-3</i>) that causes a single amino acid substitution in MED5b functions as a strong suppressor of the pathway, leading to <a>decreased soluble phenylpropanoid accumulation, reduced lignin content and dwarfism</a>. In contrast, loss of MED5a and MED5b (<i>med5</i>) results in increased levels of phenylpropanoids. In Chapter 2, we present our finding that <i>ref4-3</i> requires CDK8, a Mediator kinase module subunit, to repress plant growth even though the repression of phenylpropanoid metabolism in <i>ref4-3 </i>is CDK8-independent. Transcriptome profiling revealed that salicylic acid (SA) biosynthesis genes are up-regulated in a CDK8-dependent manner in <i>ref4-3,</i> resulting in hyper-accumulation of SA and up-regulation of SA response genes. Both growth repression and hyper-accumulation of SA in <i>ref4-3</i> require CDK8 with intact kinase activity, but these SA phenotypes are not connected with dwarfing. In contrast, mRNA-sequencing (RNA-seq) analysis revealed the up-regulation of a DNA J protein-encoding gene in <i>ref4-3</i>, the elimination of which partially suppresses dwarfing. Together, our study reveals genetic interactions between Mediator tail and kinase module subunits and enhances our understanding of dwarfing in phenylpropanoid pathway mutants.</p> <p>In Chapter 3, we characterize other phenotypes of <i>med5</i> and <i>ref4-3</i>, and find that in addition to the up-regulated phenylpropanoid metabolism, <i>med5</i> show other interesting phenotypes including hypocotyl and petiole elongation as well as accelerated flowering, all of which are known collectively as the shade avoidance syndrome (SAS), suggesting that MED5 antagonize shade avoidance in wild-type plants. In contrast, the constitutive <i>ref4-3 </i>mutant protein inhibits the process, and the stunted growth of <i>ref4-3 </i>mutants is substantially alleviated by the light treatment that triggers SAS. Moreover, <i>ref4-3</i> mimics the loss-of-function <i>med5</i> mutants in maintaining abscisic acid (ABA) levels under both normal and drought growth conditions. The phenotypic characterization of <i>med5</i> mutants extend our understanding of the role of Mediator in SAS and ABA signaling, providing further insight into the physiological and metabolic responses that require MED5.</p> <p>In Chapter 4, we explore the function of MED5 and CDK8 in gene expression regulation by investigating the effect of mutations in Mediator including <i>med5</i>, <i>ref4-3</i>, <i>cdk8-1</i> and <i>ref4-3 cdk8-1</i> on genome-wide Pol II distribution. We find that loss of MED5 results in loss of Pol II occupancy at many target genes. In contrast, many genes show enriched Pol II levels in <i>ref4-3</i>, some of which overlap with those showing reduced Pol II occupancy in <i>med5</i>. In addition, Pol II occupancy is significantly reduced when CDK8 is disrupted in <i>ref4-3</i>. Our results help to narrow down the direct gene targets of MED5 and identify genes that may be closely related to the growth deficiency observed in <i>ref4-3</i> plants, providing a critical foundation to elucidate the molecular function of Mediator in transcription regulation.</p>
108

Forest and landscape restoration at Pontal do Paranapanema: ecological attributes of forest restoration in a coffee agroforestry system / Restauração da paisagem florestal no Pontal do Paranapanema: indicadores ecológicos em sistemas agroflorestais com café sombreado

Badari, Carolina Giudice 12 February 2019 (has links)
A direct consequence of disorganized human population growth and the indiscriminate use of natural resources are the reduction of area and the fragmentation of native ecosystems, as they transform into agricultural areas. In this scenario, agroforestry systems (AFS) may be an alternative to reconcile restoration, conservation and local agricultural production. However, there is a diversity of AFS, and its use as a forest restoration strategy is still uncertain, mainly because we lack evaluations based on ecological indicators from those systems. Thus, we compared ecological indicators measured in a coffee agroforestry system in the Pontal do Paranapanema with those inform conventional restoration plantings of the same age and with regional reference ecosystems. We measured natural regeneration density and richness; canopy cover by native species and aboveground biomass and compared among sites using an ANOVA, followed by Tukey\'s test for mean comparison. Aiming to understand the factors influencing the ecological indicators of forest restoration in coffee AFS, we performed generalized linear models (GLM) using density of coffee and native trees, biomass, percentage of animal-dispersed trees, distance to the nearest forest remnant and richness of tree species as predictor variables and percentage of canopy cover and density and richness of natural regeneration as response variables. The reference forests had the highest values for forest structure indicators, followed by AFS and finally by the conventional restoration plantings. However, we found a greater diversity of tree species planted in the AFS and a natural regeneration similar to that found in the reference ecosystems. Despite coffee density in the AFS negatively influencing natural regeneration, the coffee AFS had greater ecological performance than the conventional restoration, being a viable alternative for forest restoration. We conclude that AFS with coffee and native tree species play an important ecological role in the FLR in Pontal do Paranapanema, reconciling productivity with forest restoration. / Um reflexo direto do crescimento desordenado da população humana e das atividades antrópicas é a diminuição e a fragmentação da área ocupada por ecossistemas nativos e sua substituição por áreas agrícolas. Neste cenário, os sistemas agroflorestais (SAF) podem ser uma alternativa para conciliar restauração, conservação e produção agrícola local. No entanto, tendo em vista a diversidade de SAFs, sua adoção como estratégia de restauração florestal ainda carece de estudos que avaliem os níveis de indicadores ecológicos de cada sistema. Neste sentido, comparamos os indicadores ecológicos de sistemas agroflorestais com café e espécies arbóreas nativas no Pontal do Paranapanema, com os de plantios convencionais de restauração florestal de mesma idade (12-15 anos) e ecossistemas de referência regionais. Medimos a densidade e a riqueza da regeneração natural, a cobertura do solo por espécies nativas e a biomassa acima do solo e as comparamos entre as áreas pela análise de variância ANOVA seguida da comparação de médias pelo teste de Tukey. Buscando compreender os fatores que influenciam os indicadores ecológicos da restauração florestal no SAF, analisamos modelos lineares generalizados, tendo biomassa, porcentagem de árvores zoocóricas, distância do remanescente florestal mais próximo, densidades de café, riqueza e densidade de árvores nativas como variáveis preditoras, e porcentagem de cobertura do dossel, densidade e riqueza da regeneração natural como variáveis respostas. As florestas de referência tiveram os maiores valores para indicadores de estrutura florestal, seguidas pelos SAFs e pelos plantios convencionais de restauração florestal. Entretanto, encontramos elevada diversidade de espécies arbóreas nos SAFs e valores próximos aos das florestas de referência para a diversidade da regeneração natural. Embora a densidade de plantas de café influencie negativamente a regeneração natural, os SAFs apresentaram um melhor desempenho ecológico que as áreas de restauração convencional, correspondendo à uma alternativa viável para restauração florestal. Desta forma, concluímos que os sistemas agroflorestais estudados desempenham um papel ecológico importante na restauração da paisagem florestal no Pontal do Paranapanema, conciliando produção com restauração florestal.
109

"Estudo colorimétrico da translucidez de materiais restauradores odontológicos" / Colorimetric Study of the translucency of restorative odontologic materials.

Goveia, Jane Cleide 07 April 2005 (has links)
Quando um dente anterior é restaurado toda uma técnica de proteção ao tecido remanescente e a recuperação funcional do elemento dental podem ser comprometidas se a escolha da cor do material restaurador empregado não for adequada. A familiaridade com as teorias da cor e da interação da luz com a matéria pode ajudar na tarefa de escolha da tonalidade do material restaurador. O desafio na busca de um material restaurador ideal na sua função estética sempre foi obter a translucidez própria do esmalte dental. Contudo, essa translucidez faz com que o material restaurador sofra influência da cor de fundo, que pode ser da cor do material de proteção, ou mais normalmente da cor da dentina. No que tange as atividades de restauração estética odontológico, através deste trabalho foi possível concluir que: 1) A colorimetria pode ser um importante meio na seleção e na comunicação de tonalidades de materiais restauradores; 2) Os resultados obtidos confirmam que a cor de fundo exerce grande influência sobre a cor do resultado final da restauração; e 3) Os guias de tonalidade devem ser reformulados de tal forma que levem em consideração a espessura do material restaurador e a cor de fundo. / When an anterior tooth is restorated, the whole remaining tissue protection technique and functional recuperation of the dental element can be compromised if the choice of the color of the restorative material is not adequate. The familiarity with the color and light interaction with matter theories may help with the task of choosing the restorative material shade. The challenge in searching for an ideal restorative material in its esthetic function was always obtaining the proper translucency of dental enamel. However, this translucency makes the restorative material suffer an influence of the background color, which can be the protection material color or, more commonly, the dentine color. Concerning the odontologic esthetic restorative activities, it was possible to conclude from this work that: 1) Colorimetry can be an important way for the selection and communication of the restorative material shades; 2) The results show that the background color has a large influence on the final color of the restoration; and 3) The shade guides must be reformulated so that it take into consideration the thickness of the restorative material and background color.
110

Ecofisiologia de Clausena excavata Burm. F. (Rutaceae), uma espécie exótica invasora /

Vieira, Daniela Cristine Mascia. January 2009 (has links)
Orientador: Massanori Takaki / Banca: Victor José Mendes Cardoso / Banca: Sergius Gandolfi / Banca: Débora Leonardo dos Santos / Banca: Dalva Maria Silva Matos / Resumo: As espécies invasoras são reconhecidas como um dos mais importantes e difíceis fatores que influenciam a conservação dos ecossistemas nativos. Na restauração de ambientes degradados, estas espécies podem afetar profundamente a trajetória do recobrimento vegetal pelas espécies nativas e, conseqüentemente, a composição do ecossistema. Um fator importante para o sucesso de algumas espécies vegetais invasoras é a plasticidade fenotípica, dandolhes grande capacidade de aclimatação em diversas condições ambientais. O conhecimento dos fatores ambientais e das características da planta que contribuem para o sucesso das espécies invasoras é de grande importância para predizer a habilidade de invasão e para esforços de manejo. Neste contexto, o objetivo principal deste estudo foi conhecer algumas características fisiológicas e ecológicas de Clausena excavata Burm. f., uma espécie de árvore exótica reconhecida como invasora em algumas regiões no mundo, no intuito de compreender o sucesso da espécie como invasora e contribuir com informações relevantes para possíveis tentativas de controle. Primeiramente, foram avaliados os efeitos da luz e da temperatura em sua germinação (condição controlada) e o efeito da luz na emergência de suas plântulas (condição natural, a pleno sol e sob a copa das árvores). As sementes germinaram tanto na presença como na ausência de luz, nas temperaturas de 20 a 35°C, sem diferença entre a porcentagem de sementes germinadas nas diferentes temperaturas. Sementes mantidas a 20°C, em ambas as condições de luz, germinaram mais lentamente em relação às demais temperaturas. Independente da temperatura, na presença de luz as sementes apresentaram uma germinação muito mais sincronizada do que aquelas mantidas no escuro. Tais resultados mostraram que as sementes de C. excavata são fotoblásticas neutra. Em campo, a emergência... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The invasive species are recognized one of more important and difficult factors that prejudice the conservation of native ecosystems. In the restoration of degraded environment, these species can to affect profoundly the trajectory of recovery by native species and, therefore, the ecosystems composition. An important factor to the success of invasive species is their phenotypic plasticity, which gives them a great ability to adjust in several environmental conditions. The knowledge of environmental factors and plant characteristics that contribute to the success of invasive species is very important to predict the invasion capacity and to manage efforts. In this context, the main objective of this study was to know some physiological and ecological characteristics of Clausena excavata Burm. f., a nonnative tree species recognized as invasive somewhere of the world, with intention to understand the success of this species as invasive and to contribute with relevant informations for a possible management. At first, were evaluated the effects of light and temperature on their seeds germination (controlled condition) and the effect of light on seedling emergence (natural condition, at full sun and shade). The seeds germinated in presence and absence of light, from 20 to 35°C, without difference among the germination percentage at different temperatures. Seeds maintained in 20°C, at both light conditions, germinated slowly than others temperatures. Independent of temperature, in light the seeds showed a germination more synchronized than the seeds kept in darkness. Those results showed that C. excavata have neuter photoblasics seeds. On the field, the emergence occurred at both environments, but at full sun all seeds produced a seedling. The seedling emergence occurred with same rate and synchronization index on two tested conditions. Thereafter, the seedlings were observed with purpose... (Complete abstract click electronic access below) / Doutor

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