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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.
181

Photodegradation of grass litter in semi-arid grasslands : a global perspective

Köchy, Martin January 2006 (has links)
In a recent contribution in Nature (vol. 442, pp. 555-558) Austin & Vivanco showed that sunlight is the dominant factor for decomposition of grass litter in a semi-arid grassland in Argentine. The quantification of this effect was portrayed as a novel finding. I put this result in the context of three other publications from as early as 1980 that quantified photodegradation. My synopsis shows that photodegradation is an important process in semi-arid grasslands in South America, North America and eastern Europe.
182

Modelling Net Primary Productivity and Above-Ground Biomass for Mapping of Spatial Biomass Distribution in Kazakhstan

Eisfelder, Christina 21 August 2013 (has links) (PDF)
Biomass is an important ecological variable for understanding the responses of vegetation to the currently observed global change. The impact of changes in vegetation biomass on the global ecosystem is also of high relevance. The vegetation in the arid and semi-arid environments of Kazakhstan is expected to be affected particularly strongly by future climate change. Therefore, it is of great interest to observe large-scale vegetation dynamics and biomass distribution in Kazakhstan. At the beginning of this dissertation, previous research activities and remote-sensing-based methods for biomass estimation in semi-arid regions have been comprehensively reviewed for the first time. The review revealed that the biggest challenge is the transferability of methods in time and space. Empirical approaches, which are predominantly applied, proved to be hardly transferable. Remote-sensing-based Net Primary Productivity (NPP) models, on the other hand, allow for regional to continental modelling of NPP time-series and are potentially transferable to new regions. This thesis thus deals with modelling and analysis of NPP time-series for Kazakhstan and presents a methodological concept for derivation of above-ground biomass estimates based on NPP data. For validation of the results, biomass field data were collected in three study areas in Kazakhstan. For the selection of an appropriate model, two remote-sensing-based NPP models were applied to a study area in Central Kazakhstan. The first is the Regional Biomass Model (RBM). The second is the Biosphere Energy Transfer Hydrology Model (BETHY/DLR). Both models were applied to Kazakhstan for the first time in this dissertation. Differences in the modelling approaches, intermediate products, and calculated NPP, as well as their temporal characteristics were analysed and discussed. The model BETHY/DLR was then used to calculate NPP for Kazakhstan for 2003–2011. The results were analysed regarding spatial, intra-annual, and inter-annual variations. In addition, the correlation between NPP and meteorological parameters was analysed. In the last part of this dissertation, a methodological concept for derivation of above-ground biomass estimates of natural vegetation from NPP time-series has been developed. The concept is based on the NPP time-series, information about fractional cover of herbaceous and woody vegetation, and plants’ relative growth rates (RGRs). It has been the first time that these parameters are combined for biomass estimation in semi-arid regions. The developed approach was finally applied to estimate biomass for the three study areas in Kazakhstan and validated with field data. The results of this dissertation provide information about the vegetation dynamics in Kazakhstan for 2003–2011. This is valuable information for a sustainable land management and the identification of regions that are potentially affected by a changing climate. Furthermore, a methodological concept for the estimation of biomass based on NPP time-series is presented. The developed method is potentially transferable. Providing that the required information regarding vegetation distribution and fractional cover is available, the method will allow for repeated and large-area biomass estimation for natural vegetation in Kazakhstan and other semi-arid environments.
183

Spectral Mixture Analysis for Monitoring and Mapping Desertification Processes in Semi-arid Areas in North Kordofan State, Sudan

Khiry, Manal Awad 16 August 2007 (has links) (PDF)
Multi-temporal remotely sensed data (MSS, TM and ETM+)were used for monitoring and mapping the desertification processes in North Kordofan State, Sudan.A liear mixture model (LMM) was adopted to analyse and the desertification proccesses by using the image endmembers. interpretation of ancillary data and field observation was adopted to verfiy the role of human impacts in the temporal changes in the study area. The findings of the study proved the powerfull of remotely sensed data in monitoring and mapping the desertification processes and come out with valuable recommendations which could contribute positively in reducing desert encroachment in the area.
184

From conduits to communities : plant water use strategies and evapotranspiration in a semi-arid ecosystem in south-western Australia

Mitchell, Patrick John January 2009 (has links)
[Truncated abstract] Understanding the ecohydrological dynamics of native vegetation can provide a benchmark for future efforts to restore landscape hydrology and allow predictions of potential landscape responses to climate uncertainty and associated changes in vegetation cover. The key drivers of evapotranspiration (Et) involved in maintaining a hydrological balance that minimises deep drainage in semi-arid ecosystems operate at a range of scales, and in this thesis I assessed the water relations of functionally and taxonomically diverse plant communities in south-western Australia from the leaf-level to ecosystem scale. For three key communities; heath shrubland, mallee (small multistemmed eucalypt) -heath, and open eucalypt woodland, populating a typical catenary sequence of soil types along a slope, I addressed the following questions: 1) What are the predominant water use strategies of wheatbelt native plant communities and what underlying trade-offs determine the distribution of plant water use strategies along the topographical gradient? 2) What are the roles of soil water and hydraulic limitation in controlling the spatial and temporal dynamics of transpiration in different functional types? 3) What is the magnitude and partitioning of total Et in the woodland community and what processes determine Et fluxes on a seasonal and annual basis? 4) What are the seasonal differences in Et among contrasting community-types and how do these patterns relate to canopy attributes and transpiration capacity along the topographical gradient? A key philosophical step in working with species-rich communities was to develop the concept of 'hydraulic functional types' (HFTs) to identify groupings of species using associations of physiological and morphological traits that define their hydrological functioning. .... However, as shallow soils dried during spring and summer, Et fluxes were significantly lower at the heath site (0.35 versus 0.66 mm day-1 for the woodland in February), demonstrating that the seasonality of Et fluxes differentiates communityscale contributions to regional water balance. Land-surface exchange of water over native vegetation is by no means uniform, but varies according to the spatial and temporal availability of water along topographical gradients. In general, shallow soils present fewer opportunities for water use partitioning and favour drought hardiness and a transpiration response that tracks recent rainfall patterns, whereas deeper soils promote greater differentiation in water use strategy and support canopies responsive to atmospheric demand. This thesis provides a unique description of ecosystem water balance in a global biodiversity hotspot by viewing complex vegetation mosaics in terms of their relevant hydrological units. This information is fundamental to sustainable agroforestry and revegetation efforts and our ability to gauge possible changes in vegetation structure and function under a changing climate.
185

Qualidade de ?gua como tema para a socializa??o do conhecimento cient?fico em regi?o semi-?rida brasileira

Sodr? Neto, Luiz 19 February 2008 (has links)
Made available in DSpace on 2014-12-17T15:54:48Z (GMT). No. of bitstreams: 1 LuizSodreN.pdf: 706113 bytes, checksum: 88c078a470be695106dfecd70878c72e (MD5) Previous issue date: 2008-02-19 / During the dry and rainy periods, in the Piranhas-Assu river hydrographic basin, variations in bacterioplankton and trophic state indexes were studied in the lotic and lentic environments. The means of total bacterial density wavered in the order of 107 organisms. mL-1 and they were higher in the rainy period. Cocci bacteria were numerically predominant in all sampling points, influencing the total abundance of bacterioplankton. Total bacterial biomass varied from 659 to 1997,3 ?gC.L-1 due to the high values of filaments cellular volume. Total phosphorus amounted 108 ?g.L-1 and it had a positive correlation with chlorophyll a (r = 0,94; p < 0,05) during dry period, when these variables presented higher concentrations. There wasn t a high spatial variation. The low transparency of water and the phosphorus and chlorophyll concentrations indicated eutrophic or hipereutrophic levels in studied points of reservoir. These variables, associated with high density and biomass values found, alert to the necessity of a constant monitoring of the semi-arid aquatic ecosystems, where the quality of water is affected by dry occurrence / Varia??es no bacteriopl?ncton e nos ?ndices de estado tr?fico em ambientes l?tico e l?ntico de trechos da bacia hidrogr?fica do rio Piranhas-Assu foram estudadas nos per?odos seco e chuvoso. As m?dias das densidades bacterianas totais oscilaram na ordem de 107 organismos por mL de amostra, sendo mais elevadas no per?odo de chuva. As c?lulas em forma de cocos foram numericamente predominantes em todos os locais, influenciando consideravelmente a abund?ncia total do bacteriopl?ncton. A biomassa bacteriana total variou de 659 a 1997,3 ?gC.L-1 em fun??o dos altos valores de biovolume dos filamentos. O f?sforo total atingiu 108 ?g.L-1 e teve uma correla??o positiva com a clorofila a (r = 0,94; p < 0,05) no per?odo de estiagem, quando estas duas vari?veis apresentaram concentra??es mais elevadas. N?o houve varia??o espacial marcante. A baixa transpar?ncia da ?gua e as concentra??es de f?sforo e clorofila indicaram n?veis eutr?fico ou hipereutr?fico nos pontos estudados no reservat?rio. Estes fatores, associados aos altos valores de densidade e biomassa encontrados, alertam para a necessidade de um freq?ente monitoramento dos ecossistemas aqu?ticos de regi?o semi-?rida onde a qualidade da ?gua ? afetada pela ocorr?ncia de seca
186

Efeito do teor de gordura na elaboração de mortadela utilizando carne de caprinos e de ovinos de descarte / Effect of fat in the preparation of mortadella using meat goats or sheep for disposal

Guerra, Ingrid Conceição Dantas 16 June 2010 (has links)
Made available in DSpace on 2015-04-17T14:49:42Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1512695 bytes, checksum: 66fceb13a8ad18e1d88c0891d2ea7e36 (MD5) Previous issue date: 2010-06-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The use of meat from animals of disposal, in the preparation of processed adds them to the sale value, create jobs, and provides diversification of products offered to consumers. However, the sausage typically have large amounts of lipids in their composition to achieve the desirable sensory qualities to this type of product, generating negative attitude to them as part of a consumer market hungry for healthier products. A possible solution to this impasse is to use lowfat meats such as beef and goats and sheep. This study aimed to present new options for the use of goat meat and sheep culling through studies of the effect of fat in the preparation of mortadella goats and sheep with details of the microbiological quality, chemical, physical and sensorial this product and to determine its shelf-life in cold storage. For each type of meat were prepared mortadella added 10, 20 and 30% fat pigs. The meat used as raw material for the preparation of sausages as well as products made with different percentages of lipids showed microbiological and physical chemistry in accordance with existing legislation. In evaluating the sensory quality of products, except for the texture attribute of formulations added 10% lipids, all other parameters were obtained acceptance rate exceeding 70%, therefore, all formulations sensory acceptability. In the evaluation of shelf-life in four storage times (1, 10, 20 and 30 days), all formulations were within the recommended by law as to the physico-chemical and microbiological being thus able to human consumption. It follows therefore that the use of cuts of meat from animals of disposal is a viable alternative for the formulation of sausage, because it generates high-quality products microbiological, physical and chemical in accordance with the law and good sensory acceptance. / A utilização de carnes de animais de descarte na elaboração de produtos processados agrega-lhes valor de venda, gera empregos e proporciona diversificação dos produtos oferecidos ao mercado consumidor. No entanto, os embutidos cárneos em geral apresentam grandes quantidades de lipídeos em sua composição para que atinjam as qualidades sensoriais desejáveis a este tipo de produto, gerando atitude negativa quanto aos mesmos por parte de um mercado consumidor ávido por produtos mais saudáveis. Uma possível solução para este impasse é a utilização de carnes com reduzido teor lipídico, como a carne de caprinos e ovinos. O presente trabalho teve como objetivo apresentar novas opções de utilização da carne de caprinos e de ovinos de descarte, através de estudos do efeito da gordura na elaboração de mortadela caprina e ovina, apresentando dados da qualidade microbiológica, química, física e sensorial deste produto, além de determinar sua vida-de-prateleira em armazenamento refrigerado. Para cada tipo de carne foram elaboradas mortadelas adicionadas de 10, 20 e 30% de lipídeos suínos. As carnes utilizadas como matéria-prima para a elaboração dos embutidos, bem como os produtos elaborados com os diferentes percentuais de lipídeos apresentaram qualidade microbiológica e físico-química em conformidade com a legislação em vigor. Na avaliação da qualidade sensorial dos produtos, exceto para o atributo textura das formulações adicionadas de 10% de lipídeos, todos os demais parâmetros avaliados obtiveram índice de aceitação superior a 70%, sendo portanto, todas as formulações aceitas sensorialmente. Na avaliação da vida-de-prateleira, em quatro tempos de armazenamento (1, 10, 20 e 30 dias), todas as formulações apresentaram-se dentro do recomendado pela legislação quanto aos parâmetros físico-químicos e microbiológicos estando portanto, aptas para o consumo humano. Conclui-se portanto, que a utilização de cortes de carne de animais de descarte é uma alternativa viável para a formulação de embutidos cárneos, pois gera produtos de qualidade microbiológica, física e química de acordo com a legislação e bem aceitos sensorialmente.
187

Nordeste Semiárido, semidramático: uma análise do cotidiano do Semiárido na revista Nordeste

Lopes, Poliana Souza de Queiroz 10 June 2013 (has links)
Submitted by Leonardo Cavalcante (leo.ocavalcante@gmail.com) on 2018-04-05T15:05:21Z No. of bitstreams: 1 Arquivototal.pdf: 489608084 bytes, checksum: 4ae1f86093207d94cf7aaca58fee5ada (MD5) / Made available in DSpace on 2018-04-05T15:05:21Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 489608084 bytes, checksum: 4ae1f86093207d94cf7aaca58fee5ada (MD5) Previous issue date: 2013-06-10 / The present study aimed to understand how journalism shapes Brazilian semi-arid Region (Northeast Region), based on the review of reports published in Nordeste (Northeast) Magazine. The choice for the analysis of this magazine was to be able to identify how this press media, which is produced in the northeast regional limits, deals with the semiarid. For that, this research had a corpus made of 12 copies of the magazine, published during the period from January to December of the year 2012. The choice of empirical clipping allowed us to investigate how this magazine talks about the region throughout the year. The theoretical reflections followed a path of approach that included a bibliographical survey about the semiarid region in Northeast, considering both its historical and geographical configuration, as well as the discoursed weaved about this portion; of Everyday life as a style and of the journalist as a reality producer. The methodology used was the formist paradigm, from the social forms. Through this procedure, it was possible to surpass the ready and fixed models and to look to the deeper appearance of daily life. Forms of gender, language, sources and themes were used as categories of analysis. / O presente estudo buscou entender como o jornalismo constrói o Nordeste Semiárido, a partir do exame de reportagens publicadas na revista Nordeste. A opção pela análise da revista, se deu para se poder identificar como um veículo impresso, produzido nos limites regionais nordestinos, trata este Semiárido. Para isso, se teve como corpus 12 exemplares da revista, publicados durante o período de janeiro a dezembro de 2012. A escolha do recorte empírico permitiu analisar como este veículo impresso discorre sobre a região durante todo o ano. As reflexões teóricas seguiram um caminho de abordagem que compreendeu um apanhado bibliográfico a respeito do Nordeste Semiárido, considerando tanto a sua configuração histórica e geográfica, quanto os discursos tecidos sobre essa porção; do cotidiano enquanto estilo e do jornalismo construtor de realidades cotidianas. A metodologia utilizada foi o paradigma formista, a partir das formas sociais. Por meio deste procedimento foi possível ultrapassar os modelos prontos e fixos e buscar a profunda aparência da vida cotidiana. Formas de gênero, de linguagem, de fontes e de temáticas, foram utilizadas como categorias de análise.
188

Processamento do fruto do juazeiro para obtenção da farinha e do óleo.

DINIZ, Valdefran Maia. 12 June 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-12T20:55:21Z No. of bitstreams: 1 VALDEFRAN MAIA DINIZ – TESE (PPGEP) 2016.pdf: 1513284 bytes, checksum: 65b7ff42de41578c05d4e5e300bb65c0 (MD5) / Made available in DSpace on 2018-06-12T20:55:21Z (GMT). No. of bitstreams: 1 VALDEFRAN MAIA DINIZ – TESE (PPGEP) 2016.pdf: 1513284 bytes, checksum: 65b7ff42de41578c05d4e5e300bb65c0 (MD5) Previous issue date: 2016-08 / No semiárido brasileiro as espécies vegetais da Caatinga são utilizadas para diversos fins. Dentre elas, o fruto do juazeiro (Zizyphus joazeiro Mart.), muito utilizado pelas populações locais, mas pouco conhecido cientificamente quanto ao seu potencial alimentício. Por ser um fruto sazonal e a sua produção ser quase totalmente desperdiçada, estudos de métodos tecnológicos de conservação e a caracterização nutricional poderiam contribuir para agregar valor e disponibilizar mais uma fonte alimentar regional. Assim, objetivou-se com esse trabalho o processamento e caracterização do fruto do juazeiro para a obtenção da farinha (casca e polpa) e do óleo (sementes). A caracterização dos frutos in natura consistiu na composição centesimal, valor energético e atividade de água. A farinha foi obtida através de secagem convectiva dos frutos, determinando-se as curvas de secagem nas temperaturas (50, 60 e 70 ºC) e velocidades de ar (1,0, 1,5 e 2,0 m/s). Nas farinhas resultantes da cinética foram determinadas as composições centesimais e naquela que apresentou teor de umidade dentro do determinado pela legislação para farinhas (15%) foram realizadas análises físico-químicas, composição de aminoácidos e minerais. Do óleo extraído das sementes foi determinado o perfil de ácidos graxos e, deste, calculados os índices de qualidade nutricional, (HH, IA e IT). De acordo com as análises dos dados da cinética de secagem, o modelo de Page ajustou satisfatoriamente os dados experimentais, a secagem ocorreu no período de taxa decrescente, verificando-se que a temperatura teve maior influência. A farinha que apresentou menor teor de umidade (12,40%) foi a seca, na temperatura de 70 ºC e velocidades de ar de 2,0 m/s. Os resultados da caracterização da farinha mostraram as potencialidades nutricionais do fruto. O teor de açúcares totais de 41,55% e valor energético de 340,13 Kcal/100 g. O perfil de aminoácidos apresentou todos os aminoácidos essenciais, com destaque para o triptofano acima do padrão de referência estabelecido pela FAO/adultos (18 mg/100 g proteína). Dos minerais destacaram-se o potássio (1118 mg/100 g), cálcio (356 mg/100 g), magnésio (114 mg/100 g) e ferro (3 mg/100 g). No perfil de ácidos graxos do óleo, observou-se maior quantidade de ácidos graxos insaturados (64,51%) em relação aos saturados (34,41%). Os ácidos graxos predominantes no perfil foram o ômega-9 (37,31%), o palmítico (16,80%), o ômega-3(15,63%), esteárico (11,80%) e ômega-6 (10,20%). / In the brazilian semi-arid climate the vegetal species from the Caatinga are diversely employed. Among them, the fruit of the juazeiro (Zizyphus joazeiro Mart.), wideley used by local population, but little known scientifically about their alimentary potential. Being a seasonal fruit and its production is almost entirely wasted, studies of technological methods of conservation and nutritional characterization could help to add value and deliver on a regional food supply. Thus, the aim of this work was the processing and characterization of juazeiro fruit to obtain flour (peel and pulp) and oil (seeds). The characterization of raw fruits is the chemical composition, energy and water activity. The flour was obtained by convective drying of fruits, stablishing the drying curves in the temperatures (50, 60 and 70 ºC) and the air speeds (1.0, 1.5 and 2.0 m/s). In the flours resulting from the kinetic it was determined the centesimal composition, and one that has moisture content within the specified by law for flour (15%), physicochemical analysis were performed, such as aminoacid and mineral composition ones. The oil extracted from the seeds, it was stablished the fatty acids profile and its calculated the indexes of nutritional quality, (HH, IA e IT). According to the kinetic drying data analysis, the Page model satisfactorily fitted the experimental data, the drying occurred in the falling rate period, finding that the temperature had the greatest influence. The flour that has a lower moisture content (12,40%) was dried at a temperature of 70 ºC and 2,0 m/s air speed. The results of the characterization of the flour showed the nutritional potential of the fruit. The total sugar content of 41.55% and energy value of 340.13 Kcal / 100 g. The amino acid profile presented all the essential amino acids, especially the tryptophan, above the reference standard stablished by FAO/adults (18 mg/100 g protein). The minerals potassium is highlighted (1118 mg / 100g), calcium (356 mg / 100 g), magnesium (114 mg / 100 g) and iron (3 mg / 100 g). In profile oil fatty acids, it was observed a bigger amount of unsaturated fatty acids (64,51%) compared to the saturated ones (34,41%). The prevailing fatty acid in the profile was the monounsaturated omega-9 (37,31%), the palmitic (16,80%), the omega-3 (15,63%), stearic (11,80%) and omega-6 (10,20%).
189

Coping with rural risk : assets, labour allocation, migration, and community networks

Malaeb, Bilal January 2016 (has links)
Given the importance of agricultural income for rural households, erratic weather conditions pose an austere threat to these households' livelihoods. This thesis explores ways through which households in agrarian economies smooth their consumption, engage in community networks, and readjust their labour allocation in response to shocks. In a setting of inherent risk, absence of institutional insurance, and labour market inefficiencies, poor households are often left to their own devices to cope with risk. The aim of this study is to examine the different risk-coping strategies adopted by households in rural India, assess their effectiveness, and derive implications for public policy. The results suggest that, in an environment characterised by agro-climatic risk, households are able to self-insure and smooth their consumption in the face of income shocks. Their coping mechanisms, however, may reduce their resilience to future shocks. In fact, small landholders tend to rely more heavily on their productive asset stock, while medium landholders find it optimal to preserve and accumulate their productive assets when exposed to exogenous income shocks. Households also change their labour allocation and reduce their self-employment in agriculture. Furthermore, households in rural areas can migrate to urban areas or engage in societal risk-sharing arrangements to mitigate the risk. The results of this thesis suggest that being part of a community network discourages individuals' migration and increases the likelihood of undertaking riskier activities. The findings also confirm the importance of portfolio adjustments and the diversification of household assets in buffering consumption. These conclusions form the basis of several policy implications, the most important of which is providing formal insurance schemes to encourage the accumulation of assets, technology, and skills.
190

Cinética das propriedades mecânicas durante a maturação dos frutos e avaliação da qualidade fisiológica das sementes de abóbora "Jacarezinho". / Kinetics of mechanical properties during fruit ripening and evaluation of the physiological quality of "Jacarezinho" pumpkin seeds.

FIGUEIRÊDO NETO, Acácio. 11 June 2018 (has links)
Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-06-11T14:17:04Z No. of bitstreams: 1 ACÁCIO FIGUEIREDO NETO - TESE PPGEA 2012..pdf: 36488715 bytes, checksum: f4cbebe212c4e906fda1a7703532628e (MD5) / Made available in DSpace on 2018-06-11T14:17:04Z (GMT). No. of bitstreams: 1 ACÁCIO FIGUEIREDO NETO - TESE PPGEA 2012..pdf: 36488715 bytes, checksum: f4cbebe212c4e906fda1a7703532628e (MD5) Previous issue date: 2012 / A cultura da abóbora é de uma maneira geral um bom negócio para vários produtores que se situam no semiárido, principalmente na região do Vale do São Francisco. A abóbora 'Jacarezinho' é uma das hortaliças de grande importância no Nordeste do Brasil, destacando-se pelo seu valor comercial. A qualidade fisiológica das sementes é de vital importância para que se obtenha sucesso em uma lavoura e as sementes de abóbora não fogem dessa realidade. O conhecimento da maturidade dos frutos e sementes, durante o processo de maturação é de interesse dos produtores, uma vez que auxilia no controle de qualidade. Com isso, objetivou-se neste trabalho avaliar a cinética da maturação dos frutos e a qualidade das sementes da abóbora 'Jacarezinho' sob diferentes épocas de colheita, e relacioná-los com as transformações físicas e fisiológicas que ocorreram simultaneamente durante o amadurecimento e o armazenamento nas condições do semiárido nordestino. O trabalho foi conduzido em uma área experimental de horticultura irrigada pertencente ao Departamento de Agronomia da Universidade Estadual da Bahia, no Laboratório de Sementes da Embrapa Seimárido em Petrolina - PE e no Laboratório de Ensaios de Materiais da Engenharia Mecânica da Universidade Federal do Vale do São Francisco em Juazeiro - BA. Em uma determinada área foi cultivado sementes de abóbora da variedade 'Jacarezinho' para seus frutos serem colhidos em épocas determinadas no período de dezembro de 2010 a março de 2011. Após a colheita, os frutos passaram pelas análises com ensaios de compressão com posterior extração das sementes, para determinação do teor de água e a realização dos testes de germinação e vigor. As sementes atingiram a maturidade fisiológica no tempo de 50 a 60 dias após antese configurando o tempo da colheita dos frutos para produção de sementes. Para as análises da pesquisa sobre comportamento mecânico dos frutos o resultado mostra que com o aumento do tempo de maturação ocorre o aumento da rigidez dos frutos com consequente aumento da carga máxima para atingir maiores deformações. E o tempo mais aconselhável para colheita e transporte foi entre 30 a 40 dias após antese para comercialização dos frutos. E por fim, com o armazenamento das sementes foi verificado que os maiores valores de germinação foram obtidas acondicionadas em embalagem de plástico para os doze meses e papel para os três meses de armazenamento desta cucurbitácea. / The pumpkin crop is generally a good deal for many producers who are located in the semiarid, mainly in the region of the San Francisco. The pumpkin 'Jacarezinho' is one o f the vegetables of great importance in northeastem Brazil, especially for its commercial value. It is known that the physiological seed quality is of vital importance in order to obtain success in a farming and pumpkin seeds do not escape this reality. Knowledge o f the maturity o f fruits and seeds during the maturation process is of interest to producers because it helps in quality control. Thus the objectives of this study: to evaluate the kinetics of fruit maturation and quality of seeds Pumpkin 'Jacarezinho' under different harvest times, and relate them to physical and physiological changes that occur simultaneously during the ripening and storage conditions of the semiarid northeast. The study was conducted in an experimental area of irrigated horticultura from the Department of Agronomy, State University of Bahia, in the Seed Laboratory of "Embrapa" semiarid in Petrolina - PE and Materials Testing Laboratory of Mechanical Engineering, Federal University o f the San Francisco in Juazeiro - BA. In a given area was grown pumpkin seeds variety 'Jacarezinho' for its fruits being harvested at certain times during the period December 2010 to March 2011. After harvesting, the fruits passed through the analysis of compression tests with subsequent extraction of the seeds, to determine the moisture content and the tests of germination and vigor. Seeds reached physiological maturity at the time of 50 to 60 days after anthesis by setting the time of fruit harvest for seed production. For the analysis of research on mechanical behavior of the fruit the result shows that with increasing aging time is increased stiffness of the fruit with a consequent increase o f the maximum load to achieve greater deformation. And the longer advisable to harvest and transport was between 30 to 40 days after anthesis to fruit commercialization. And finally, with the seed storage was found that the highest germination values were obtained in plastic packaging for the twelve months and paper for the three months storage of cucurbit.

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