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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.
31

Competitividade de produtos "in natura" e processados do Brasil no comércio exterior / Competitivity of Brazilian “in natura” and processed export products

Rosário, José Baptista Fernando do 28 March 2001 (has links)
Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-07-07T19:01:57Z No. of bitstreams: 1 texto completo.pdf: 483921 bytes, checksum: 73e3f4f7aa631d16974032664dd39e85 (MD5) / Made available in DSpace on 2017-07-07T19:01:57Z (GMT). No. of bitstreams: 1 texto completo.pdf: 483921 bytes, checksum: 73e3f4f7aa631d16974032664dd39e85 (MD5) Previous issue date: 2001-03-28 / O comércio substancialmente, exterior de produtos “in natura” sempre contribuiu, na geração de divisas para o país. Entretanto, o excesso de oferta desses produtos no mercado internacional, na década de 80, estimulado, principalmente, pela súbita alta de preços internacionais durante a década anterior e pelo aprofundamento do protecionismo à agricultura dos países desenvolvidos, acabou acarretando uma queda de preços, que, para alguns produtos, ainda persiste. Os preços baixos estimularam o processamento desses produtos, ou seja, a agregação de valor foi a saída estratégica encontrada por parte de muitos países para continuar participando de uma economia globalizada onde impera a competitividade. Dada esta tendência, este estudo procurou analisar a competitividade de alguns dos principais produtos agrícolas de exportação do Brasil , “in natura” e processados, nos complexos soja e laranja, e determinar os principais fatores que levaram à alteração na participação dos referidos produtos na pauta de exportações brasileiras. Os procedimentos analíticos deste trabalho basearam-se em indicadores de vantagem comparativa revelada e da taxa de câmbio real, sintetizando, respectivamente, a abordagem ex-post e um conceito macro. Além desses indicadores, fez-se uma análise comparativa da evolução dos preços de exportação entre o Brasil e o resto do mundo, representando o grau de capacitação detida pelas firmas (eficiência). Os resultados mostraram que o Brasil vem perdendo competitividade no mercado internacional de derivados de soja (farelo e óleo) e aumentando a vantagem relativa na exportação do produto “in natura” (soja em grão). Isso se deve, principalmente, ao desempenho exportador da Argentina, principal competidor do Brasil e atual líder no ranking das exportações mundiais de produtos processados do complexo. A perda de competitividade está associada, também, à desoneração do ICMS na exportação dos produtos do complexo, principalmente o produto “in natura”, devido a um diferencial tributário que retinha a soja em grão no país e estimulava o processamento desta. No que se refere ao complexo laranja, o Brasil apresentou vantagem comparativa na exportação do suco de laranja concentrado e desvantagem nos demais produtos, laranja “fruta” e suco de laranja não-concentrado. Em ambos os complexos, a taxa de câmbio influenciou, negativamente, o desempenho do Brasil no mercado internacional e os preços permaneceram favoráveis em quase todo o período analisado. Os desafios competitivos do Brasil são externos às empresas, razão por que algumas deficiências precisam ser dirimidas para consolidação da tendência das exportações brasileiras em favor dos produtos processados, dentre as quais a infra-estrutura de transportes, portuária e de armazenagem, que deve ser melhorada, e a política tributária, que deve ser revista. / Committee Members: Antônio Carvalho Campos and Fátima Marília Andrade de Carvalho. Export of “in natura” products has substantially contributed to generate exchange values in Brazil. However, a surplus of these products in the international market during the 1980s - encouraged mainly by the sudden international price increase registered during the previous decade and by a growing agricultural protectionism by the developed countries, caused a price fall which still persists for some products. The low prices have encouraged the processing of these products, i.e., value aggregation was the strategic solution found by many countries in order to continue participating in a globalized economy ruled by competitivity. Based on this trend, this work aimed to analyze competitivity of some of the main Brazilian agricultural export products, both “in natura” and processed (soybean and orange), to determine the main factors leading to changes in their exportation. The analytical procedures used in this work were based on indicators of revealed comparative advantage and real exchange rate, synthesizing, respectively, the ex-post approach and a macro concept. A comparative analysis of export price evolution was also conducted, including Brazil and the rest of the world, representing the degree of capacity of the companies involved, i.e., their efficiency. The results showed that Brazil has been losing competitivity ground in the international market of soybean by- products (soybean meal and oil) but increasing its relative advantage in the export of “in natura” (soybean grain) products. This is mainly due to Argentina’s export performance, Brazil’s main competitor and current world export leader of these processed products. Competitivity loss is also associated to ICMS dispensation in the export of these products, especially those “in natura”, due to a tax differential that prevented soybean grain from being exported, encouraging its processing. As for orange, Brazil presented a comparative advantage in concentrated orange juice export and a disadvantage for orange “fruit” and non- concentrated orange juice. For both products, the exchange rate has negatively influenced Brazil’s performance in the international market, with the prices remaining favorable during almost all the analyzed period. Brazil’s competitive challenges are alien to the companies and that is why some deficiencies - such as transport, port and storage infrastructures (which needs improvement) and tax policy (which must be reviewed), - must be eliminated, so that consolidation of Brazilian export trend towards processed products takes place.
32

Péče o lesy v evropské soustavě chráněných území NATURA 2000 ve Francii

Daňková, Eva January 2009 (has links)
No description available.
33

Společenstva obojživelníků a jejich ochrana na lokalitě Vojenské cvičiště Rokycany

Kalousová, Štěpánka January 2006 (has links)
No description available.
34

Výnosové srovnání lesního hospodaření v podmínkách ŠLP ML Křtiny bez vlivu a s vlivem opatření NATURY 2000

Jurník, Martin January 2011 (has links)
No description available.
35

Aktuální problémy ochrany přírody a krajiny na Krnovsku

Vaňková, Lenka January 2007 (has links)
No description available.
36

Problematika újem způsobených vlastníkům lesa z důvodu ochrany přírody

Bartošek, Stanislav January 2008 (has links)
No description available.
37

Estudo químico de Pavonia multiflora A. St-Hil. (Malvaceae), planta endêmica do Espírito Santo.

LOPES, L. G. 27 March 2014 (has links)
Made available in DSpace on 2016-08-29T15:35:35Z (GMT). No. of bitstreams: 1 tese_7655_Leandra Gobira.pdf: 1528402 bytes, checksum: d570f2c6d1e6f3959ce5057ffbac18dd (MD5) Previous issue date: 2014-03-27 / Este trabalho descreve o estudo fitoquímico das folhas da espécie Pavonia multiflora visando o isolamento e a identificação de seus metabólitos secundários que possam ser direcionados à busca por atividade biológica. A espécie de estudo é endêmica do Estado do Espírito Santo, e é encontrada na região de Mata Atlântica. Essa espécie ainda não possui registros de estudos fitofarmacológicos na comunidade científica. Portanto, neste trabalho, as partições hexânica e acetato de etila, provenientes do extrato etanólico das folhas de Pavonia multiflora, foram submetidos a diversas metodologias cromatográficas visando o isolamento dos seus constituintes químicos. Tais métodos cromatográficos incluíram Cromatografia em Camada Delgada Comparativa, Cromatografia Líquida em Coluna, Cromatografia em Camada Delgada Preparativa, Cromatografia Líquida de Alta Eficiência e Cromatografia Líquida à Vácuo, as quais tiveram diversificadas fases estacionárias e eluentes. Através de técnicas espectroscópicas e espectrométricas, foram identificadas dez substâncias, sendo quatro compostos fenólicos: o ácido phidroxibenzóico, ácido p-cumárico, ácido vanílico e ácido ferúlico; cinco derivados terpênicos: loliolida, vomifoliol, 4,5 dihidroblumenol A, 3-oxo-α-ionol e o blumenol C; e um triterpeno esterificado derivado do taraxerol, o p-metoxibenzoato de taraxerol. O extrato total foi ensaiado em diferentes concentrações como inibidor das catepsinas K, L e V, o qual apresentou atividade inibitória da catepsina K e V com concentração de 500 μg/mL.
38

Agroforestry systems for ammonia air quality management

Bealey, William James January 2016 (has links)
Air pollution can lead to environmental impacts. Over the past decades there have been some success stories reducing pollutant emission, namely sulphur dioxide (SO2). However, impacts on ecosystems from atmospheric nitrogen (N) pollution are still seen as a major threat for European biodiversity. Across Europe over 70% of Natura 2000 sites are at risk for eutrophication with over 70% of the Natura 2000 area in Europe (EU28( exceeding critical loads for nutrient nitrogen deposition. Agricultural ammonia is a key contributor to the threat to these sites due to the close proximity of agricultural activities and protected sites. Source attribution modelling using an atmospheric transport model showed that agricultural livestock production in the UK is the dominant nitrogen source for N disposition across the UK Natura 2000 network. Nearly 90% of all sites had livestock as their dominant source, contributing 32% of the total nitrogen deposition across the whole network. 76% of all Special Areas of Conservation (SAC) sites exceeded their critical load for nutrient nitrogen, representing 74% of the entire SAC area. The extent of exceedance is also notable with many sites experiencing depositions of >50 kg N/ha/yr over the critical load. the situation for acidity critical load exceedance is less sever, by 51% of sites are still exeeded. Legislation to regulate pollutant emissions to air and protect biodiversity are often not integrated, and there has been no common European approach for determining the impacts of nitrogen deposition on individual Natura sites, or on conservation status. Off-site sources of air pollution present difficulties in assessing and attributing impacts, because deposition can result from local sources (1-2 km), or very far away sources (>1000 kms). Managing nitrogen losses on the farm and improving the efficient use of nitrogen are key components for overall reduction in NH3 emissions. Many nitrogen management options are available to abate ammonia from agricultural activities. On the one hand, technical and management measures include controlling emissions from manure storage and spreading, livestock feeding strategies, and improving housing systems. Trees, on the other hand, are effective scavengers of both gaseous and particulate pollutants from the atmosphere, making tree belts potentially effective landscape features to support ammonia abatement strategies. Using a coupled deposition and turbulence model the recapture efficiency of tree planting around ammonia sources was estimated. Using different canopy structure scenarios, tree depths and differing leaf area density (LAD) and leaf are index (LAI) were adjusted for a main canopy and a backstop canopy. Recapture efficiency for ammonia ranged from 27% (trees planted around housing systems), up to 60% (under-story livestock silvopastoral systems). Practical recapture potential was set at 20% and 40% for housing and silvopastoral systems respectively. Model results from scaling up to national level suggest that tree planting in hot spot areas of ammonia emissions would lead to reduced N deposition on nearby sensitive habitats. Scenarios for on-farm emission control through tree planting showed national reductions in nitrogen deposition to semi-natural areas of 0.14% (0.2 kt N-NHx) to 2.2% (3.15 kt N-NHx). Scenarios mitigating emissions from cattle and pig housing yielded the highest reductions. The afforestation strategy showed national-scale emission reductions of 6% (8.4 kt N-NHx) to 11% (15.7 kt N-NHx) for 25% and 50% afforestation scenarios respectively. Increased capture by the planted trees also generated an added benefit of reducing long-range transport effects, including a decrease in wet deposition of up to 3.7 kt N-NHx (4.6%) and a decrease in export from the UK of up to 8.3 kt N-NHx (6.8%). Agroforestry measures for ammonia abatement were shown to be cost-effective for both planting downwind of housing and in silvopastoral systems, when costs to society were taken into account. Planting trees was also cost-effective from a climate change perspective. Comparing the cost per kg of NH3 abated showed that planting trees is a method of ammonia emission mitigation comparable with other (technical) measures. The costs for planting trees downwind of housing were calculated at €2.6-7.3/kg NH3. Agroforestry for ammonia abatement offers multiple benefits for the farmer and synergistic effects for society as a whole including i) carbon sequestration. ii) visibility screening around housing units, iii) imporved animal welfare for silvopastoral systems, iv) reducing critical load exceedance on protected sites, v) price advantage of 'woodland chick' productions, vi) supporting the Industrial Emission Directive (IED) requirements for emission reduction, vii) supporting national afforestation policies. The results of this work support the notion that in the emerging discussion about the values of ecosystem services and the role of nature-based solution to tackle persistent environmental challenges, tree planting has a large potential in rural and urban environments.
39

Právní úprava soustavy NATURA 2000 / Legal regulation of the Natura 2000 system

Chudíková, Jana January 2011 (has links)
114 Resumé The topic of my diploma thesis is "Legal regulation of Natura 2000 Network". Natura 2000 is a a network that seeks to preserve biodiversity within the territory of the EU. Natura 2000 was imposed by the article 3 of the Habitats Directive, which along with the Bird Directive are the most important legal acts aiming at biodiversity conservation in the European Union. The main purpose of this work is the legal analysis of the legal arangement of the Natura 2000 Network by taking the european context under consideration. First three chapters describes the concept of Natura 2000 Network and its history, including a short description of biodiversity protection within the internatinal law (relevant international agreements). The next chapter is focused on the European Union Law. Firstly, it describes the history of environmental policy within the european law and the institutions and funds connected to Natura 2000 Network. The law base of Nature 2000 network is formed by the European Directive 2009/147/EEC on the conservation of the wild birds (so called "Birds Directive") and the European Directive 92/43/EEC on the conservation of the natural habitats and of wild fauna and flora (so called "Habitats Directive"). These directives enable designation of two types of protected areas - Special Protected...
40

Daphnia magna bioassays to detect novel eco-toxicological effects of prioritary and emergent contaminants

Campos, Bruno 10 January 2014 (has links)
There is increasing evidence that the presence of many emerging pollutants in aquatic ecosystems may have detrimental effects on aquatic biota. Of special concern are those emerging pollutants that may act as putative endocrine disrupters in non-vertebrate species, causing unexpected effects. In chapters 2, 3 and 4, I assessed the effects of two pharmaceuticals belonging to the group of "SSRIs": fluoxetine and fluvoxamine, used to treat depression; and the detergent 4-nonylphenol. SSRIs and 4-nonylphenol, increased offspring production and SSRIs also increased the juvenile developmental rates at limiting but not at high food ration levels. SSRIs increased juvenile development rate, clutch size, and decrease offspring size at low and intermediate levels of food rations, changing the perception of food levels making them to behave like they grew at higher food levels. Enhanced reproductive effects of SSRIs were reversed by the presence of the 5-HT antagonist cyproheptadine, indicating that in D. magna SSRIs targeted serotonin metabolic paths like in humans. Physiological assays showed that adult females exposure to SSRIs increased oxygen consumption rates and decreased carbohydrate levels. These changes did not affect survival under starving conditions, but they significantly affected the capacity of the exposed animals to survive under anoxic conditions. 4-nonylphenol increased offspring number but decreased offspring size. These responses have detrimental fitness effects since smaller offspring takes longer to mature and reproduce and having less offspring directly affects population growth rates. The analysis of the D. magna transcriptome showed that serotonin metabolism, neuronal developmental processes, carbohydrates and lipid metabolism pathways appeared as selectively affected by SSRIs treatment, whereas 4-nonylphenol deregulated genes from the carbohydrate metabolism and the ecdysone regulatory pathway. SSRIs show a MoA consistent with its pharmacological effect in humans while 4-nonylphenol effect seems to be performed through changes in the ecdysone regulatory pathways. In chapter 5 I evaluated the extent to which different forms of nano-TiO2 aggregate with microalgae, edible particle concentration. Effects were assessed using different assays. Assays included standard chronic reproduction 21-day tests, but also custom designed tests. The latter included two exposure scenarios: semi-static and re-suspension of algae. Results indicated the aggregation of nanoparticles. Nanoparticle aggregates interacted with the algae cells, forming clusters. Large TiO2-algae agglomerates settled readily, dramatically depleting the concentration of available food for Daphnia with dramatic effects on reproduction and fitness. These results indicate that nano-TiO2 may affect the transfer of energy throughout the planktonic aquatic food webs increasing the settlement of edible particles from the water column. In chapter 6 I tried to characterize the presence and activity of the multixenobiotic resistance proteins (MXR) in D. magna. I sequenced new partial DNA sequences, coding for full transporters and studied their transcriptional pattern across lifestages and with juveniles exposed to MXR inducers. All the genes were transcribed early in embryos and some of them were induced in juvenile stages by pentachlorophenol and mercury. Associated efflux activity was monitored using three fluorescent substrate dyes that are specific of different mammalian transporter types, combined with specific MXR transporter inhibitors (chemosensitizers). Dye accumulation assays indicated that MXR is functional in juveniles and induced by pentachlorophenol, mercury and dacthal. Toxicity bioassays performed with model substrates of ABCB1 (mitoxantrone) and ABCC (chlorambucil) transporters applied in combination chemosensitizers showed synergic toxic effects. This means that the MXR system is active and plays an important role detoxifying contaminants. / El efecto negativo que los contaminantes emergentes presentes en ecosistemas acuáticos tienen sobre la biota, es cada vez más evidente. En los capítulos 2, 3 y 4 se han evaluado los efectos sobre D. Magna del detergente 4-nonilfenol y de dos fármacos pertenecientes al grupo de los inhibidores selectivos de la recaptación de la serotonina (ISRS): fluoxetina y fluvoxamina, empleados en el tratamiento de la depresión. Cuando la disponibilidad de alimento es intermedia o se reduce al límite, la presencia de ISRS o de 4-nonilfenol produce un aumento en la descendencia. Además, los ISRS también aceleran el desarrollo de los juveniles. La presencia de ISRS modifica la percepción de los niveles de comida, provocando que D. magna se comporte como si dispusiera de abundante alimento. Este incremento en la tasa de reproducción se invirtió en presencia de Ciproheptadina, un antagonista de los receptores 5-HT, indicando que, al igual que en humanos, los ISRS afectaban a las rutas metabólicas de la serotonina. Ensayos fisiológicos mostraron que las hembras adultas expuestas a ISRS aumentaban su consumo de oxígeno y que los niveles de carbohidratos descendían. Estos cambios no afectaron la supervivencia, pero si la capacidad de los animales expuestos a sobrevivir en condiciones anóxicas. 4-nonilfenol produce un aumento en el número de descendientes, mas éstos tienen menor tamaño y por tanto tardan más en madurar y reproducirse. El análisis del transcriptoma de D. magna muestra que el metabolismo de la serotonina, los procesos de desarrollo neural y el metabolismo de lípidos y carbohidratos están afectados por el tratamiento con ISRS, mientras que 4- nonilfenol desregula genes del metabolismo de los carbohidratos y provoca cambios en la ruta que regula la edicsona. En el Capítulo 5, se evalúa hasta qué punto diferentes formas de nano-TiO2 se agregan con microalgas y deste modo afectar la concentration de partículas comestibles.Se usaron diferentes ensayos para valorar los efectos. Dichos ensayos incluyen el test estándar de exposición crónica durante 21 días, así como otros tests diseñados específicamente para este estudio. Éstos últimos contemplan dos escenarios: exposición a algas de um modo semiestático y exposición a algas con resuspensin continua. Los resultados indican que las nanoparticulas se agregan y sus agregados interaccionan con las algas formando clusters. Los aglomerados TiO2-Alga de mayor tamaño sedimentan rápidamente, reduciendo drásticamente la concentración de alimento disponible y, por tanto, afectando gravemente a estado general y reproductivo de la Daphnia. Estos resultados alertan del efecto que el nano-TiO2 puede tener en los procesos de transferencia de energía a lo largo de toda la cadena alimentaria planctónica. En el capítulo 6 se caracteriza la presencia y actividad MXR en D. Magna. Se secuenciaron RNA, que codifican para estos transportadores y se estudiaron los patrones transcripcionales a lo largo de diferentes estadios de D. magna y, también, con juveniles expuestos a inductores de MXR. Los resultados mostraron que ya en los embriones se observa transcripción de todos los genes, y algunos de éstos se inducían en juveniles expuestos a pentaclorofenol y mercurio. Mediante el uso de tres sustratos fluorescentes específicos a distintos tipos de transportadores, se monitorizó la actividad de expulsión del pigmento combinada con inhibidores específicos del transportador MXR. Los ensayos de acumulación de estos sustratos indican que MXR es funcional en juveniles y que es inducido por pentaclorofenol, mercurio y Dacthal. Los ensayos de toxicidad realizados con sustratos modelo de los transportadores ABCB1 (mitoxantrona) y ABCC (clorambucil) en combinación con chimiosensibilizadores, demostraron efectos tóxicos sinérgicos. Estos resultados indican que el sistema MXR está activo y juega un papel muy importante en los procesos de detoxificación

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