Pepper (Capsicum annuum L.), which originates from tropical environments is particularly sensitive to low temperatures. The Canadian climate, with its risks of cool temperatures during spring time, greatly limits the production of this temperature-sensitive crop. This work dealt with pepper plant exposure to low temperatures (9 and 15$ sp circ$C), at two early growth stages. 'Lady Bell' pepper plants were grown from seed under controlled conditions of 21$ sp circ$C, 50 $ pm$ 10% R.H., 16/8 light/dark cycle and 300 $ mu$molm$ sp{-2} / rm s sp{-1}$ PAR at the canopy level. Once plants had reached either the cotyledonary or the three-true-leaf stage low temperatures were applied. Treatment conditions lasted until plants had produced three additional leaves after which they were returned to the pretreatment conditions. Evaluations were made at six recognized developmental stages and included destructive measurements for growth analysis, pigment content and leaf anatomical features as well as weekly non-destructive measurements. Results showed that plant responses to 9 and 15$ sp circ$C were not the same when applied at the cotyledonary or the three-true-leaf stage. Overall growth decreased with decreasing temperatures and plants exposed to 9$ sp circ$C at the cotyledonary stage died. Plants exposed to cold treatments underwent a whole complex of changes in morphology which included reduction in leaf size, stem diameter, internode length and on leaf, branch and developing fruit abnormalities. Dry matter accumulation and distribution, leaf area production and leaf pigment levels varied with treatments. The anatomical changes which included alterations in epidermal and mesophyll cell dimensions and arrangement were reminiscent of a general response to a wide range of stress conditions reported for several other plant species. Upon return to the control temperature recovery was clearly observed especially in those plants exposed to the 15$ sp circ$C treatments. Plants ex

No description available.

No description available.

A main concern in fisheries science has been to identify an accurate index of fish abundance. An underlying paradigm in the science has been that the amount of effort (calculated in hours and standardized for boat size) spent fishing was the best variable to be used to account for the variation in catches. The use of the ratio, catch per unit of effort (cpue), assumes that variations in fish abundance are due to human-controlled processes above the ocean's surface. It does not account for variation due to oceanographic processes that affect fish behaviour and movement patterns below the ocean's surface. This study investigated the possibility that oceanographic factors such as temperature, salinity and depth could have effects on the variations observed in the apparent abundance of a demersal rockfish, Pacific Ocean Perch (Sebastes alutus. Gilbert). Simultaneous monitoring of physical variables and fish abundance estimation was achieved by attaching oceanographic equipment to the fishing gear of commercial vessels, monitoring the acoustic equipment and sampling the fish catch. It was found that Perch prefer a temperature range from 6.7 °C, down to at least 4.8 °C and that their movement patterns are linked to the movement of these temperatures by coastal wind patterns. Perch prefer areas with steep bathymetry, characterized by frontal activity due to interactions between the local bathymetry and tidal currents. Concerns that sampling only from highly successful commercial vessels may have biased abundance estimates, prompted the analysis of historical records of fish catch and government research surveys. Analyses between different boat sizes, different areas and different seasons from the original historical data base and a corrected subset revealed that it was mainly differences between areas that was responsible for the biasing of estimates. Deeper areas predictably produced more fish for all sizes of boats, but were fished more often by the larger boats used in the study. Therefore the field abundance estimates are likely to be biased towards areas of larger perch concentrations. / Science, Faculty of / Zoology, Department of / Graduate

This study examines the effects of a low oxygen environment, in concert with fluctuating temperature and salinity conditions, on the nearshore depth distributions (0-1 m) and flood tide movements of juvenile chinook (Oncorhynchus tshawytscha) and chum (O. keta) salmon. Comparisons are made between an unpolluted and a sewage polluted estuarine intertidal flat in the Fraser River estuary, British Columbia, the polluted area being characterized by the regular occurrence of low dissolved oxygen levels. Results are based on 380 beach seine samples taken between April and June of 1984. In general, chum and chinook salmon of increasing length were captured in increasing depths, though this pattern was modified by seasonal changes in water temperature. Low dissolved oxygen conditions in deeper waters may have been responsible for the presence of larger, and often sluggishly swimming fish in higher oxygenated surface water layers or in shallow waters near the shore. In both areas, the risk of aerial predation was high. On a flood tide, the likelihood of capturing a chinook salmon was reduced as temperatures increased and oxygen levels decreased. A combination of avoidance behaviour and a regularity in the movement patterns of chinook onto the study area in the later stages of the flood tide may account for their rare occurrence in low oxygen concentrations (<6 mg/1) and high temperatures (>20 °C). Fish mortalities were most likely to occur on the ebb tide when fish were forced into waters of low oxygen content by the drainage patterns characteristic of the polluted study area. Though wide ranges in salinity were recorded on both tidal flats, this factor was not strongly correlated to Chinook distributions. However, significantly higher salinity levels in the unpolluted area may account for the greater numbers of chum salmon captured there. An understanding of the influence of estuarine water quality conditions on the distribution of juvenile salmonids may assist in the identification of significant sources of mortality in their early marine life. This knowledge is particularly important in the evaluation of water quality changes as caused by human activity. / Science, Faculty of / Zoology, Department of / Graduate

Bibliography : leaves 102-106

Made available in DSpace on 2015-03-26T13:40:04Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2089547 bytes, checksum: 78256e3ce0b69f3185fa68080853f287 (MD5) Previous issue date: 2014-07-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate the tolerance of fruits of different banana cultivars to low temperature storage. Fruits of the cultivars Nanicão (AAA), Prata (AAB), Vitória (AAAB), Maçã (AAB) and Caipira (AAA) were used. Hands were subdivided into clusters of three fruits, which were kept in cold storage for 7, 14 and 21 days, with an average temperature of 10.53 &#61617; 0.37 °C and relative humidity of 85%. Subsequently, the clusters were transferred to the temperature of 22 &#61617; 0.39 °C, to complete the ripening. The experiment was in a split plot design, having five cultivars in the plots and evaluation days in the subplots, in a completely randomized design with four replications and one cluster per experimental unit. Data were analyzed by variance analyses and regression. The Dunnett test at 5% probability was used to compare data from control (start of storage) with those of the end of storage. Each storage period was analyzed separately. The fruits of all cultivars remained green after 21 days of storage at 10.53 C &#61617; 0.37 °C. Fruits of the cultivar Nanicão did not complete the ripening after they were transferred to 22 °C, when stored for 7 days at low temperature. These fruits were firmer, with green skin, low soluble solids and low titratable acidity. After 21 days of cold storage, the fruits of all cultivars completed ripening, when transferred to room temperature. The chilling injury increased with the advance of the cold storage for all cultivars. Fruits of Nanicão , Caipira and Maçã had more obvious symptoms of chilling injury. Fruits of Prata and Vitória were more tolerant to cold storage at a temperature of 10.53 °C for up to 21 days, showing normal ripening after transfer to 22 °C. / O objetivo deste trabalho foi avaliar a tolerância dos frutos de diferentes cultivares de bananeira a baixa temperatura de armazenamento. Foram utilizados frutos dos cultivares Nanicão (AAA), Prata (AAB), Vitória (AAAB), Maçã (AAB) e Caipira (AAA). Utilizaram-se buquês com três frutos, mantidos em câmara fria por 7, 14 e 21 dias, com temperatura média de 10,53 &#61617; 0,37 °C e umidade relativa do ar de 85%. Posteriormente, os buquês foram transferidos para a temperatura de 22 &#61617; 0,39 °C, para completar o amadurecimento. O experimento foi em esquema de parcelas subdivididas, tendo-se nas parcelas cinco cultivares e nas subparcelas os dias de avaliação, no delineamento inteiramente casualizado, com quatro repetições e um buquê de três frutos por unidade amostral. Os dados foram analisados por meio de análises de variância e regressão. O teste de Dunnett foi utilizado para comparar os dados da testemunha (início do armazenamento) com os dos dias do fim do armazenamento, a 5% de probabilidade. Cada período de armazenamento foi analisado separadamente. Os frutos dos cultivares estudados permaneceram verdes após 21 dias de armazenamento à 10,53 &#61617; 0,37 °C. Frutos do cultivar Nanicão não completaram o amadurecimento após serem transferidos para a temperatura de 22 °C, quando armazenados por 7 dias à baixa temperatura, apresentando frutos mais firmes, com casca verde, baixos teores de sólidos solúveis e acidez titulável. Após 21 dias de armazenamento refrigerado, os frutos de todos os cultivares completaram o amadurecimento, depois de transferidos para temperatura ambiente. Os danos por frio aumentaram com o avanço do tempo de armazenamento refrigerado, para todos os cultivares. Nanicão , Caipira e Maçã apresentaram sintomas mais evidentes de dano por frio. As bananas Prata e Vitória mostraram-se mais tolerantes ao armazenamento refrigerado na temperatura de 10,53 °C por até 21 dias, exibindo amadurecimento normal após a transferência para a temperatura de 22 °C.

The introduction of this paper describes three thermoeletrical effects and their properties. It also deals with thermoelectrical cells, which are using Seebeck´s and Peltrier´s effects. The paper decribes principles how the Peltier´s cells work, their mathematical model, construction and practical use. The paper shows what kinds, shapes and output we can meet at the market and which kinds of parameters regulate their selection. The paper suggests the possibility to measure characteristic behaviour and quantity during laboratories tasks and their evaluations. At the conclusion is adduced the suggestion of laboratory task together with theoretically made pilot protocol.

No description available.

Este trabalho investigou o efeito da temperatura nos sistemas aneróbios com células imobilizadas tendo como estudo de caso um sistema anaeróbio em duas fases. Inicialmente, foram realizados experimentos preliminares com um sistema em duas fases composto por Reator Acidogênico Horizontal Tubular (RAHT) seguido de Reator Anaeróbio Horizontal de Leito Fixo (RAHLF), nas temperaturas de 15ºC, 20ºC e 25ºC. Os resultados mostraram que o RAHT alcançou 48% de remoção de DQO e que a desvantagem da ausência de microrganismos consumidores de H2 no sistema praticamente não afetou a produção de ácido acético. Pôde-se observar que na faixa de temperatura estudada o RAHT não apresentou mudanças significativas em seu desempenho. Posteriormente foram realizados experimentos com cinco reatores metanogênicos do tipo RAHLF, alimentados com esgoto sintético simulando o efluente do RAHT, com velocidades de 10,4 cm/h, a 52,0 cm/h e temperatura de 15ºC a 35ºC. Os resultados permitiriam o desenvolvimento de um modelo empírico-estatístico para simulação do desempenho dos reatores, tendo como variáveis a velocidade superficial do líquido sobre as biopartículas e a temperatura de operação. Os resultados preditos pelo modelo demonstraram boa representatividade dos valores experimentais. Com isso, foi possível observar as influências da velocidade superficial (vs) e da temperatura, nas concentrações residuais de substrato (Sr) e nas constantes cinéticas aparentes de primeira ordem (K1app). Conclui-se então, que apesar do aumento de vs resultar em maiores valores de K1app, também foi observado aumento no valor de Sr indicando que existe um tempo de contato mínimo entre os microrganismos e o substrato. / The effects of temperature and superficial velocity in an anaerobic methanogenic immobilized cell rector of a two phase-system were investigated. Preliminarily, a Tubular Horizontal Acidogenic Reactor (THAR) followed by Horizontal-flow Anaerobic Immobilized Biomass (HAIB) composed the experimental system, operated at the temperatures of 15°C, 20°C and 25°C. COD removal efficiency of 48% was observed in the THAR. Likewise, the disadvantage of the absence of H2-consumer methanogenics microorganisms in the system almost did not affect the production of acetic acid. The temperature variation has not caused significant changes in the THAR performance. The next step was the development of experiments using five methanogenics HAIB reactors fed on synthetic wastewater simulating THAR effluent having superficial velocities from 10,4 cm/h to 52,0 cm/h and temperature from 15°C to 35°C. The results enabled the development of a statistical-empiric modeling to simulate the reactors performance using the liquid superficial velocities and the temperature operation as model variables. The model demonstrated a good agreement with the experimental values. The influence of the superficial velocities (vs) and temperature, in the substrate residual concentration (Sr) and in the first order (K1app) apparent kinetic constant was observed. Despite the K1app values have increased largely with vs, the Sr concentration also increased. These results permit to conclude that a minimum contact time between the microorganisms and the substrate may be necessary in such processes.