Orientador: Ivany Ferraz Marques Valio / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T03:19:02Z (GMT). No. of bitstreams: 1 Abrao_MarluciMundin_D.pdf: 2033158 bytes, checksum: 02bd87759812f0f20bce7ff1ed06a9d8 (MD5) Previous issue date: 2007 / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Orientador: Flavio Antonio Maes dos Santos / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T20:45:37Z (GMT). No. of bitstreams: 1 Virillo_CarolinaBernucci_D.pdf: 2082404 bytes, checksum: 73a7c246ad5ac8eccbc8fcf39ee5364b (MD5) Previous issue date: 2010 / Resumo: Os mecanismos responsáveis pela alta diversidade de espécies arbóreas em florestas tropicais têm sido alvo de intenso debate na literatura, e dentre os inúmeros mecanismos propostos, dois deles têm encontrado relativo suporte empírico: a dependência de densidade e a diferenciação de nichos. O objetivo deste trabalho foi investigar a ocorrência destes mecanismos na Floresta Ombrófila Densa Atlântica, que apresenta uma enorme diversidade de espécies vegetais, que variam em abundância, e uma grande diversidade de habitats, o que faz deste bioma um local apropriado para buscar evidências da ocorrência desses mecanismos. Foi investigada a influência da densidade de coespecíficos, da vizinhança e do microhábitat na demografia de quatro espécies arbóreas, e esperava-se que estes fatores atuassem de maneira conjunta na determinação da demografia das espécies estudadas. Em cinco áreas de 0,25 ha, duas na Floresta Ombrófila Densa de Terras Baixas (TB) e três na Floresta Ombrófila Densa Submontana (SM), foram marcados e medidos os indivíduos destas espécies, e um recenso foi realizado após dois anos para obtenção de taxas de mortalidade e recrutamento. Indivíduos com PAP (perímetro a altura do peito) > 15 cm foram acompanhados mensalmente para a avaliação da fenologia reprodutiva e do incremento diamétrico. Foi avaliada a influência da densidade de indivíduos e da distância e número de vizinhos coespecíficos na demografia das espécies. Também foi avaliada a relação da demografia com habitats específicos, dados pela declividade e pela porcentagem de abertura de dossel, assim como da fenologia reprodutiva e do incremento diamétrico com a cota de altitude e com o índice de iluminação da copa (IC). Para nenhuma das espécies estudadas foi encontrada relação entre a densidade total de indivíduos e as taxas de mortalidade e de recrutamento. Entretanto, nas áreas de maior abundância, foram encontradas associações entre os indivíduos mortos e os demais indivíduos da população, assim como diminuição da agregação conforme se considera classes de tamanho maiores, que podem ser interpretadas como evidências dos processos dependentes de densidade, indicando que os processos dependentes de distância ou densidade só se mostram importantes em situações de densidade elevada. Houve relação do número de indivíduos com a declividade para a maioria das espécies, mas foram poucas as relações significativas com a abertura de dossel. A mortalidade, o recrutamento e o crescimento dos indivíduos com PAP < 15 cm apresentaram poucas relações significativas com as variáveis ambientais (IDP e abertura do dossel), provavelmente devido ao baixo número de eventos registrados. Para duas das espécies, a fenologia reprodutiva se relacionou com a cota de altitude, mas não com o IC, indicando um aspecto da preferência de hábitat. Já o incremento diamétrico variou muito dentro de uma mesma cota altitudinal, se relacionando, para duas das espécies, com o IC, mas para as outras duas espécies nem a altitude e nem a iluminação das suas copas explicou a variação observada no crescimento. Recomenda-se que um maior número de variáveis ambientais sejam utilizadas para caracterizar os microambientes quando se busca evidências de preferências de hábitat. É provável que os mecanismos estudados não sejam mutuamente exclusivos e que eles atuem em conjunto na determinação dos processos demográficos populacionais, e assim influenciando conjuntamente na manutenção da grande diversidade de espécies arbóreas em florestas tropicais. / Abstract: The mechanisms that are responsible for the high tree species diversity in tropical forests have been intensively debated on literature, and among the several proposed mechanisms, two of them have been relatively empirically supported: the density-dependence and the niche differentiation. The aim of this work was to investigate the occurrence of these mechanisms on the Atlantic Ombrophilous Dense Forest, that has a huge plant species diversity, that vary on their abundance, and a high diversity of habitats, what makes this biome an appropriate place to seek for the existence of these mechanisms. We investigated the influence of conspecific density, neighborhood and microhabitat on the demography of four tree species, and we expected these factors to act together on determining the demography of the studied species. On five 0.25 ha area, two on the Lowland Ombrophilous Dense Forest and three on the Lower-montane Ombrophilous Dense Forest, we tagged and measured all the plants of the studied species; the plants were re-censused after two years so we obtained the mortality and recruitment rates. Plants with perimeter at breast height (PBH) > 15 cm were monthly observed to evaluate their reproductive phenology and diameter increment. We evaluated the influence of the density of plants and the number and distance of conspecific neighbors on the demography of the studied species. We also evaluated the relationship of the demographic rates with specific habitats, given by canopy openness and declivity, and of the reproductive phenology and diameter increment with the altitude and the crown illumination index (IC). We found no relationship between the total density of individuals and the mortality or recruitment rates, but on the areas of high abundance we found associations between the dead plants and the other plants of the populations, as well as lower aggregation as we considered bigger size classes, which could be interpreted as evidences of the density dependent processes, indicating that the density or distance-dependent processes are important only on high density situations. We found significant relationships between the number of individuals and declivity for the majority of species, but there were few significant associations with the canopy openness. Mortality, growth and recruitment of plants PBH < 15 cm have few significant correlations with environmental variables (declivity and canopy openness), probably because of the low number of events registered. For two of the studied species, the reproductive phenology was related to the altitude but not with IC, indicating one aspect of the habitat preference. The diameter increment showed great variation on the same altitude, and for two species it was related with IC, but for the other two neither the altitude nor the IC explained the observed variation on growth. We recommend the use of more environmental variables to characterize the microenvironments when seeking for evidence of habitat preference. It's possible that the studied mechanisms are not mutually exclusive and that they act together on determining the demographic processes, and so, influencing together the maintenance of the high tree species diversity on tropical forests. / Doutorado / Mestre em Biologia Vegetal

To examine if a rhythm can be entrained in either heart rate or oxygen consumption in late stage embryos (days 17-19.5) with light as a zeitgeber, chicken embryos were incubated in complete darkness (D:D) and 12:12 light:dark cycle (L:D). Light had no impact on oxygen consumption (390 µL O2∙min-1∙egg-1) but increased heart rate for non-internally pipped embryos (260 to 270 beats∙min-1 during light cycle). Oxygen consumption increased independent of pipping while heart rate increased (255 to 265 beats∙min-1) in D:D embryos due to pipping. A light-induced rhythm or effect occurred in heart rate but not oxygen consumption, suggesting heart rate and oxygen consumption may be uncoupled.

While ocean acidification (OA) is predicted to inhibit calcification in marine macroalgae, species whose photosynthesis is limited by current dissolved inorganic carbon (DIC) levels may benefit. Furthermore, variations in macroalgal morphology will likely give rise to a range of OA tolerance in calcifying macroalgae. One genus of calcifying macroalgae that has shown varying species’ tolerance to OA is Halimeda, a major carbonate sediment producer on tropical reefs. Species within this genus occupy a range of habitats within tropical environments (reefs and lagoons), illustrating their ability to adapt to diverse environmental conditions (e.g. carbonate chemistry, irradiance). To date it is not clear if morphological and photophysiological diversity in Halimeda will translate to different tolerances to OA conditions (elevated pCO2 and lower pH). / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

No description available.

Thesis (M. Tech.) - Central University of Technology, Free State, 2010 / The objective of this research study was to quantify the differences in average daily gain (ADG), back fat thickness (BFT), eye muscle area (EMA), fat thickness (FT) on different body parts, the feed conversion ratio (FCR) and body dimensions (by means of body measurements) of Dorper lambs exposed to supplemented light. For this study 120 Dorper lambs (115 ± 10 days old) weighing (29.76 ± 5.01kg) were used. The lambs were randomly divided into three homogeneous groups (20 castrated and 20 intact males). The three groups were then exposed to different levels of supplemented light at 145 lux (16h, 24h and normal photoperiod). The animals were fed ad libitum with pellets containing 9.5 MJ ME/kg DM and 12% CP in open pens. The animals were weighed every 7 days while ultrasound scanning of the EMA and the BFT was done at the beginning and the end of the 35 day trial. The ADG, FCR and feed intake (FI) were calculated at the end of the trial. Linear body measurements including shoulder height, body length and heart girth were taken at day 1 and day 35 respectively. All the animals were slaughtered at the end of the trail. The carcasses were then weighed, graded and the FT was measured with a caliper. The final results of the study showed that no significant differences between the three treatment groups (consisting of wethers and rams) in terms of body measurements, ultrasound scanning ADG and FCR could be detected. However, a significant difference was found between the wethers and the rams in the whole trial for ADG. The ADG of the rams exposed to 16 hours of supplemented light was significantly better than the normal photoperiod and the 24 hour light supplementation group.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The Southern Ocean (SO) is of significant interest in the understanding of the global carbon cycle and therefore many studies have been conducted to determine the limiting factors controlling the biological pump within the region. During photosynthesis phytoplankton require various nutrients such as NO3, PO4, inorganic carbon and the micronutrient Fe. The SO is a High-Nutrient Low-Chlorophyll region, therefore no macronutrient limitation is experienced by resident phytoplankton but instead the micronutrient Fe is a significant limiting factor within these waters due to limited inputs. Due to deep mixed layer depths, ice cover, low sun angles and cloud cover throughout parts of the year, light is also considered a limiting factor in the SO. Fe and light limitation cause a decrease in photosynthetic efficiency and therefore a decrease in carbon fixation capabilities. During this study we conducted five bioassay shipboard incubation experiments during two cruises along the Greenwich meridian between South Africa and the ice edge, SOSCEx during March and SAFePool during January to February, in which we varied Fe concentrations and light levels to determine the effects of Fe and light limitation or co-limitation within resident phytoplankton. Spatial and temporal variations in phytoplankton response were studied to determine varying effects of limitation across water masses and different stages of bloom decline within the study area. The combined addition of Fe and light gave the largest increase in biomass, photosynthetic capacity and nutrient uptake. In support of the hypotheses tested changes in the photosynthetic apparatus led to changes in the photosynthetic efficiency and growth of the SO phytoplankton, as a result of variations in Fe and light availability. Variability was also observed in the response of phytoplankton to Fe and light amendments due to spatial and temporal variation in resident phytoplankton communities. It was therefore concluded that both Fe and light are significant controls in the resident phytoplankton photosynthetic apparatus, photosynthetic capabilities, organic carbon fixation and therefore the biogeochemical cycles within the Atlantic sector of the SO. / AFRIKAANSE OPSOMMING: Die Suidelike Oseaan (SO) is van beduidende belang in die begrip van die globale koolstofsiklus en dus is baie studies gedoen om die beperkende faktore te bepaal wat die biologiese pomp in die streek beheer. Tydens fotosintese benodig fitoplankton verskillende voedingstowwe soos NO3, PO4, anorganiese koolstof en die mikrovoedingstof Fe. Die SO is 'n High-Nutrient Lae-Chlorofil streek, dus word geen makrovoedingstof beperking ervaar deur inwoner fitoplankton maar in plaas daarvan is die mikrovoedingstof Fe 'n beduidende beperkende faktor binne hierdie waters weens beperkte insette. As gevolg van diep gemengde laag dieptes, ysbedekking, lae son hoeke en wolkbedekking deur dele van die jaar, word lig ook beskou as 'n beperkende faktor in die SO. Fe en lig beperking veroorsaak 'n afname in die fotosintetiese doeltreffendheid en dus 'n afname in koolstof binding vermoëns. Tydens hierdie studie het ons vyf biotoets inkubasie eksperimente aan boord die skeep gedoen tydens twee vaarte langs die Greenwich meridiaan tussen Suid-Afrika en die ys rand, SOSCEx gedurende Maart en SAFePool gedurende Januarie tot Februarie, waarin ons Fe konsentrasies en lig vlakke gewissel het om die gevolge van Fe en lig beperking, of medebeperking, binne inwoner fitoplankton te bepaal. Ruimtelike en temporale variasies in fitoplankton reaksie was bestudeer om wisselende gevolge van die beperking oor watermassas en verskillende stadiums van bloei afname in die studie area te bepaal. Die gekombineerde byvoeging van Fe en lig het die grootste toename in biomassa, fotosintetiese kapasiteit en voedingsopname gegee. Ter ondersteuning van die getoetste hipoteses, veranderinge in die fotosintetiese apparaat het gelei tot veranderinge in die fotosintetiese doeltreffendheid en groei van die SO fitoplankton, as 'n gevolg van variasies in Fe en lig beskikbaarheid. Veranderlikheid is ook waargeneem in die reaksie van fitoplankton om Fe en lig wysigings weens die ruimtelike en tydelike variasie in inwoner fitoplankton gemeenskappe. Dus was dit by die gevolgtrekking gekom dat beide Fe en lig beduidende kontrole in die inwoner fitoplankton fotosintetiese apparaat, fotosintetiese vermoëns, organiese koolstof binding en daarom die biogeochemiese siklusse binne die Atlantiese sektor van die SO.

Nos estudos dos ritmos biológicos de roedores em laboratório, a roda de atividade é comumente utilizada assumindo-se que o horário da atividade em roda represente o horário de atividade do animal na natureza. Entretanto, a atividade de qualquer espécie pode ser diferente em campo e em laboratório, e tampouco se resume à atividade em roda. O tuco-tuco (Ctenomys aff. knighti) é um roedor subterrâneo diurno em campo e noturno em laboratório. Por isso, o nosso primeiro objetivo é verificar quais comportamentos são apresentados pelos tuco-tucos em laboratório, a distribuição desses comportamentos ao longo do dia e qual a contribuição da atividade em roda para o total de sua atividade e ritmicidade. O segundo objetivo é verificar quais os efeitos agudos (mascaramento) que a luz e a escuridão têm sobre a atividade dos tuco-tucos, dado que costumam ter efeitos opostos (exacerbação/inibição) em animais diurnos e noturnos. 18 machos e fêmeas adultos (150-250g) foram mantidos em gaiolas individuais e tiveram sua atividade em roda monitorada por registro automatizado, atividade geral monitorada por sensores de infravermelho e por acelerômetros, temperatura corpórea monitorada por transmissores telemétricos e comportamentos de laboratório registrados por câmeras filmadoras. Eles foram submetidos a um regime de CE 12:12 (C= 100 lux) por sete dias para que seus ritmos se sincronizassem com esse ciclo pelo mecanismo de arrastamento. Depois, receberam um pulso de luz durante a noite e, dois dias depois, um de escuridão durante o dia, para verificar se há efeito de mascaramento de seus comportamentos por luz e escuridão. Cada animal passou por esse mesmo protocolo em três condições: na primeira, sem roda de atividade; na segunda, com roda; na terceira, com roda travada. A maioria dos animais demonstrou pouca ou nenhuma ritmicidade em comportamentos específicos de laboratório que não a atividade em roda, a qual também é o principal componente da atividade geral a sofrer efeitos agudos de pulsos de luz. Um único indivíduo, quando mantido sem roda de atividade, mudou de noturno para diurno. Como a atividade em roda foi o principal comportamento inibido pela luz, cujo efeito foi quase nulo nos demais comportamentos, o mascaramento parece não ser um empecilho para a atividade diurna do tuco-tuco em campo, apesar do mascaramento ser considerado um desafio à inversão de noturnalidade para diurnalidade tanto na escala de vida individual quanto evolutiva / The running wheel is commonly used in rhythm studies assuming that the wheel-running time corresponds to the activity time in nature. The tuco-tuco (Ctenomys aff. knighti) is a subterranean rodent which is diurnal in the field and nocturnal in the lab. Because of that peculiarity, our first goal is to verify which are their behaviors in the lab, their distribution throughout the 24 hours, and how much the running wheel activity contributes to the total activity and its rhytmicity. The second goal is to verify the acute effects of light and darkness on their rhythms. 18 adult males and females (150-250g) had their behaviors recorded by cameras. Their running wheel activity, general activity and body temperature were also monitored. They were kept in a LD 12:12 (L = 100 lux) regimen and received light and darkness pulses to verify possible masking effects in their rhythms, going through the same protocol three times: 1) without wheel, 2) with wheel, and 3) with a blocked wheel. Most of animals demonstrated little to no rhythmicity in specific lab behaviors, except for running wheel activity. The wheel activity is also the main component of the general activity that is inhibited by the light pulse, but we found some masking on body temperature rhythm as well. Interestingly, there was a single individual that switched from nocturnal to diurnal when kept without a running wheel, and presented the masking patterns expected for diurnal animals. As wheel activity was the main component suffering inhibition by light, with little to no inhibition of other behaviors, it seems masking isn\'t an obstacle to the diurnal activity in the field and consequently to switches from nocturnal to diurnal activity within an individual lifetime or even in evolutionary scale for tuco-tucos

Includes bibliographical references (leaves 166-195) Addresses the nature of the central mechanisms involved in the regulation of the circadian pattern of secretion of the pineal hormone melatonin in the highly seasonal Suffolk breed of sheep. Provides new information on the behaviour of the onset and offset of melatonin secretion under different photoperiodic conditions.

A novel solid state illumination source has been developed. A two terminal dual LED has been created with the ability to control the relative intensities of the two emission peaks by varying drive current. Doping profiles have been used to extend the dynamic range of the dual LED over other reported devices. Operation of the dual LEDs is explained as a function of drive current. In addition, novel use of phosphor mixtures allows the creation of a broadband spectral power distribution that can be varied using a dual LED as an excitation source. Combinations of phosphors that have varied excitation spectra provide the ability to selectively excite different phosphors with the different LED emission peaks. First and second generations of the two terminal dual LED and the phosphor combination are discussed. The final source has the ability to mimic the light of a blackbody radiator over a range of 3200 K - 5300 K. The development of a three terminal dual LED as a pump source was prohibited by the need for a III-nitride tunnel junction, that proved unattainable in the scope of this work. However, several novel doping schemes were investigated toward this end. Finally, a circadian light source has also been developed that can affect physiological changes in humans, and a light box for entrainment of circadian rhythms in rats has been built.