• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • Tagged with
  • 10
  • 10
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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.
1

Nutrient alterations in Scots pines (<em>Pinus sylvestris</em> L.) under sulphur and heavy metal pollution

Rautio, P. (Pasi) 27 September 2000 (has links)
Abstract In this study, mineral nutrition and its relation to the vigour of Scots pines growing under the influence of sulphur, copper and nickel stress were investigated. This was done by analysing the nutrient status and needle damage of pines along a pollution transect extending from the proximity of a large S, Cu and Ni emitters on the Kola Peninsula to a background area in Finnish Lapland. Additionally, pine seedlings were exposed to Cu and Ni stress in order to gain more detailed information about the mechanisms behind metal stress. The total sulphur concentrations of the youngest needles in the vicinity of the largest point source were about double compared to those in the reference area (&lt; 800 mg in kg of dry needles vs. > 1900 mg kg-1). In the case of Cu and Ni, this difference was close to 100-fold (from 2-3 mg kg-1 to over 250 mg kg-1). While the elevated sulphur concentrations were not attributable to particle deposition, the particles on needle surfaces raised the total concentrations of Cu and Ni occasionally over 1.5-fold compared to the inside concentrations. The Mn and Zn concentrations showed a decreasing trend, whereas K and P slightly increased towards the Monchegorsk smelters. Enhanced needle senescence and tip necrosis were related to high total foliar levels of Cu, Ni and S and low levels of Zn and Mn. Stomatal chlorosis and other discolourations showed a distinct relation to high SO2 levels in the air and also to high foliar concentrations of Ca, Fe, Si and Cl. Particles deposited on needle surfaces did not cause directly visible injuries in pines. In seedlings, Cu and Ni were enriched in roots: the Ni concentration was up to 16-fold and the Cu concentration 6-fold compared to that added into the soil. While Cu was mostly retained in roots, Ni had much easier access to foliage. The effect of metal stress on other nutrients varied between nutrients, plant parts and metals added. Soil analyses from both the field study and the seedling experiment gave mostly a weak estimation about the plant availability of nutrients. Foliar nutrients remained above the deficiency limits in all studies and were hence not the primary cause for the decrease of pine vigour and the consequent growth retardation and forest decline.
2

Nutrient and sensory quality of orange-fleshed sweet potato

Leighton, Christine S. (Christina Stephanie) 22 September 2008 (has links)
Vitamin A deficiency has been recognised as a widespread problem affecting about 750 million people, mostly in developing countries. Mortality due to vitamin A deficiency can be reduced by as much as 23% with improved vitamin A status. Vitamin A's immuneenhancing aspects strengthen the body's defence system against infectious diseases such as measles, malaria and diarrhoea, thus preventing death. Children beyond the weaning age (6 months to 6 years) are most at risk. In South Africa, one in three children has a low vitamin A status, with the rural areas being most affected. Orange-fleshed sweet potato (OFSP) has emerged as a promising plant source with a high beta-carotene content that can make a significant contribution to the vitamin A intake of individuals at risk of vitamin A deficiency. The purpose of this study was to determine the nutrient and sensory quality of OFSP. To this end, the nutrient content of different cultivars of OFSP was determined as well as the sensory characteristics and consumer acceptability was established. During the first phase, four different cultivars of OFSP i.e. Resisto, W119, Jewel and A 15, plus one composite sample, all cultivated by the Agricultural Research Council (ARC)-Roodeplaat, South Africa, were sampled for nutrient analysis. During the second phase (descriptive sensory analysis), four OFSP cultivars and one white-fleshed sweet potato (WFSP) cultivar i.e. Blesbok, were evaluated. A trained sensory panel was used to establish terminology for describing the sensory attributes of the different sweet potato cultivars in terms of its aroma, texture, flavour and aftertaste attributes. Consumer preference (n=180) for OFSP and WFSP was measured by means of a paired preference test. Focus group discussions were conducted to verify findings of the consumer preference test. The results obtained from the nutrient analysis confirmed that OFSP is an excellent source of beta-carotene. A 100 g portion of cooked OFSP can provide up to 6528 ~g beta-carotene, which is approximately 136% of the RDA for vitamin A for children four to eight years. High levels of other nutrients present in OFSP were identified namely vitamin C, calcium and zinc. OFSP further contributes 28% vitamin C, 13% calcium, 15% magnesium and 75.6% zinc of their daily requirements. This study confirms the valuable contribution that OFSP can make as a food-based approach to reduce vitamin A deficiency in individuals at risk. The sensory profiles indicated that OFSP differed from WFSP in colour, flavour and texture. OFSP is generally less moist and subsequently more dense and adhesive compared to WFSP. The latter being more fibrous and less firm than OFSP. Overall OFSP had and earthy aroma which was not typical of WFSP and had a sweeter flavour. The flavour of OFSP was described as similar to that of yellow vegetables such as butternut and pumpkin. Although the different OFSP cultivars had similar characteristics, differences were found in the moist, adhesive and grainy texture attributes as well as the vegetable sweet flavour. Resisto had the sweetest in flavour, with the most dense and pasty texture of the four OFSP cultivars. W119 had the grainiest texture. No significant differences were found in the earthy aroma, sweet potato and yellow vegetable flavour attributes. It can be concluded that in flavour, few differences were found among the OFSP, except in sweetness. OFSP differed primarily from each other in texture. The consumer preference test results showed that overall 85% of respondents preferred the taste of OFSP to that of WFSP, 53% liked the orange colour a lot while 24% liked the colour a little and the remaining 22 % disliked the colour (either a lot, a little, neither like nor dislike). The majority of the consumers (86%) indicated a willingness to buy OFSP. From these results it can be concluded that the taste and colour of OFSP are acceptable to consumers of sweet potato and that it has potential to be successful in the marketplace. Given the high level of consumer acceptability of OFSP, an opportunity exists to address vitamin A deficiency through commercially viable decentralised vine production centres. Such centres could be managed by commercial-, small-scale- and subsistence farmers in South Africa in key sweet potato production areas, with adequate water supply throughout the year. However, availability of commercially produced OFSP in retail sores in recent months, may change this prospect. / Dissertation (MConsSci)--University of Pretoria, 2008. / Consumer Science / unrestricted
3

Vineyard soil matters: exploring the influence of soil physical and chemical properties on Eastern U.S. grape production

Fiola, Jaclyn Caroline 11 January 2023 (has links)
The relationship between soil and wine quality has been recognized for generations but has had limited scientific validation. Vineyard soils in the eastern United States are largely unstudied although proper site selection and good soil management have the potential to improve fruit composition for high-quality wine production. Soils that provide excessive plant-available nutrients and water often produce vigorous vegetative growth and negatively influence fruit chemistry. We investigated three aspects of Eastern vineyard soils, including potassium availability, methods of reducing infiltration, and the influence of topsoil on fruit chemistry. Our first goal was to determine the best soil sampling, processing, and extraction methods for predicting potassium availability in Mid-Atlantic vineyard soils. Excessive potassium can result in high pH fruit, which negatively affects wine quality, but until now the best methods for predicting soil-available potassium had not been investigated. We found that moist-extracted soil sampled from 0-38 cm appear to best be suited predicting vine tissue potassium. Our second goal was to test methods of reducing rain infiltration at critical times during the growing season. One of the soil stabilizers we tested successfully reduced infiltration in field trials. Vineyard trials in 2021 were compromised by dry weather, but further research is ongoing. Our final project involved a three-year investigation where we attempted to isolate the influence of soil properties on grapevines and fruit composition by monitoring vines and fruit in single vineyard blocks. The most consistent result was positive relationships between topsoil and fruit titratable acidity, suggesting that the fruit was ripening earlier in vines growing in thinner topsoil. Topsoil depth better explained differences in fruit titratable acidity than other explanatory variables including crop load and sunlight exposure of fruit. Overall, this research increased our understanding of the soil properties that influence vine growth and fruit chemistry in the Eastern US. The results will help growers improve sampling methods, fruit chemistry, and increase resilience to soil and climate related challenges. / Doctor of Philosophy / The relationship between grapes, wine, and soil has been acknowledged since the Middle Ages when monks recognized that vineyards in different places produced different-tasting wine. However, it is difficult to determine exactly how soil affects grapes and wine. In the eastern United States, growers knew that some soils were not the best for growing high quality grapes for wine, such as those that provide excessive nutrients or water to the vines, but there was little information or scientific research about it. We wanted to help growers by investigating soil properties that affect fruit quality as well as potential soil management strategies that could improve fruit quality. We fine-tuned the process of collecting, processing, and analyzing vineyard samples that growers use to determine the potassium status of their vines. Potassium can affect fruit quality so testing for it before it can affect fruit quality is crucial. We found that sampling soil to a deeper depth than usual and keeping the sample moist instead of drying it were the best practices. We also determined the best way to complete the lab analysis to best predict how much potassium the soil can provide to the vines. For our second project, we found that commercial material intended for stabilizing dirt roads slowed the seeping of rain into soil. Future research will see if vineyards can use the soil stabilizer to reduce soil water during mid-summer rains to improve fruit quality. Our final project involved monitoring vineyards over three years to see how differences in soil properties affected vine growth and fruit chemistry. The main difference in soil was the thickness of topsoil throughout each vineyard. Where there was thin topsoil, the vines were smaller and produced fruit that was less acidic. These results are likely because those fruit were ripening earlier, but we were not able to identify a specific soil property that was affecting the fruit chemistry. Overall, our results will help vineyard growers better manage their soil to hopefully produce better-quality fruit and wine.
4

Characterization of a sample population of dental hygiene patients with and without periodontal disease as determined through fatty acid and fruit and vegetable intake

Jackson, Caitlin R 01 May 2015 (has links)
This study was designed to compare the fatty acid and fruit and vegetable intake of people with and without periodontal disease. Periodontal disease affects approximately 15 percent of the developed world population. Participants filled out a food frequency questionnaire (FFQ) for both fruit and vegetable and fat intake. A sample of whole blood (EDTA) was collected to determine the fatty acid profile of participants’ red blood cell (RBC) membrane. This analytical procedure determines the average fatty acid intake of the participant over the previous 90 to 120 days. Participants were classified as case (n=10, patients diagnosed with periodontal disease) or control group (n=10, patients without periodontal disease). Our hypothesis was that the case group would have higher fat intake and lower fruit and vegetable intake, with lower levels of omega-3 fatty acids and higher levels of omega-6 fatty acids in the RBC membrane. FFQ results indicated that case participants consumed significantly higher amounts of total fat (109.02 vs. 94.46g/d; p= .05), saturated fat (35.102 vs. 28.242g/d; p= .033) and their diets had a higher percentage of total dietary fat (38.73% vs. 34.99%; p=.044). FFQ for fruit and vegetable intake showed no significance between the case and control groups (4.41 vs. 4.56 servings/d; p=.871). For the most part, there were no significant differences between the percent composition of the individual fatty acids isolated from the RBC membrane or in ratios of omega-3 to omega-6 fatty acid groups as determined by RBC fatty acid analysis. Results indicated a numerically lower intake of omega-3 fatty acids in the case than in the control group. Likewise, there was a numerically higher intake of omega-6 fatty acids in the case group. These numbers demonstrate a trend towards the hypothesis being correct and patients with periodontal disease consuming more omega-6 fatty acids and less omega-3 fatty acids.
5

A Longitudinal Analysis of Energy and Nutrient Intake of Breastfeeding and Formula Feeding Postpartum Women

Lorenz, Melissa 10 October 2013 (has links)
No description available.
6

Juvenile Green Turtle (chelonia Mydas) Foraging Ecology:feeding Selectivity And Forage Nutrient Analysis

Gilbert, Eliza 01 January 2005 (has links)
For the endangered green turtle, Chelonia mydas, a fundamental component of recovery and conservation is an understanding of its foraging ecology. Foraging optimality models suggest animals will select resources of high quality over those of low quality. For green turtles, this behavior is important, as sufficient quantities of nutritionally adequate forage items are necessary for growth and reproduction. One intrinsic element in the understanding of green turtle foraging ecology is to identify and document the availability and quality of forage resources preferred by green turtles. The objectives of this study were: 1) determine whether juvenile green turtles showed a feeding preference by comparing prey items in the diet to the availability of those items in the habitat, 2) identify species for which there was selection or avoidance, 3) identify nutritional factors determining selection or avoidance of prey items, and 4) evaluate the nutritional content of the diet. This research was conducted by comparing lavage samples from juvenile green turtles to samples from benthic surveys within the habitat. To determine feeding preference, Ivlev's Electivity Index was used to compare ingested species of algae with those available in the habitat. Nutritional analysis of forage was conducted to identify possible nutrients relating to feeding preference. Juvenile green turtles selectively foraged on Chlorophyta and Rhodophyta. Results indicate that diet selection was based on nutritional content. Both the composite diet and the main diet item, Hypnea spp, had a higher gross energy value, were higher in protein, and lower in fiber than prey items that were avoided. Conservation of green turtles requires effective habitat management, which must be informed by an understanding and evaluation of the habitat. For juvenile green turtles, this study indicates that habitats dominated by Chlorophyta and Rhodophyta may be more important for the health of green turtle populations than habitats dominated by Phaeophyta.
7

Beach-cast fertilizers for cultivation of carrots and radishes on Swedish Gotland : The effect on crop size and nutrient composition

Ögren, Sofie January 2020 (has links)
In the eutrophicated Baltic, algal blooms with toxin-producing algae and plant overgrowth is a large threat to the marine environment, humans and animals. The use of external nutrient inputs into agriculture, such as mineral fertilizers (NPK), is reaching the Baltic through runoff which causes a constant, linear nutrient flow from land to the sea, which is one of the main contributors to accelerated eutrophication. Beach-cast is rich in nutrients and plant promoting substances and was widely used as fertilizer on Gotland before the introduction of NPK. Nowadays large amounts of beach-cast are washed up on the shores of Gotland and most of it is not used. Using beach-cast as fertilizer could contribute to a decrease in external nutrient input into the Baltic and increase a circular flow of nutrients. This study was a part of a broader project operated by KTH with the purpose of evaluating beach-cast as a potential bioresource. The aim of this study was to examine the effects on nutritional content and crop size from the usage of composted beach-cast as fertilizer in comparison with the NPK fertilizer in outdoor cultivation of radish and carrots on Gotland. After the crops were cultivated and harvested, the mass of the root and haulm of the carrot and radishes was determined along with quantification of the content of carbohydrates, pigments, main vitamins and fatty acids. The result revealed a significant increase in 1) mass for three out of four (for all but the carrot root which borderlines the limit of 95% significance), 2) mass ratio between root/blast for the radish, 3) concentration of beta-carotene, vitamin A and fatty acids for the carrot root and 4) concentration of chlorophyll for both haulm. Other observed differences, although not statistically significant, was an increased carrot root mass, increased in concentration of anthocyanin for radish, unchanged mass ratio between carrot root/blast, increase B3 vitamin concentration for all crops, increased concentration of carbohydrates for carrots and decreased concentration for radish, decrease in fatty acids for carrot haulm and radish root and haulm and finally a decrease in vitamin C for all crops. The use of beach-cast as fertilizer has shown to induce growth of the crops, and the majority of the quality parameters were in the same range or exceeded in comparison with the crops cultivated with NPK. A complementary use of beach-cast fertilizer could thus prove beneficial for farmers and at the same time decrease the external nutrient input to the Baltic. / Algblomning och giftalger i övergödda Östersjön är ett stort hot för den marina miljön, människor och djur. Extern input av näringsämnen till lantbruket, i form av exempelvis mineralgödsel (NPK), når Östersjön via avrinning och orsakar en konstant, linjär näringstillförsel från land till hav, vilket är en av de huvudsakliga orsakerna till ökad övergödning. Det näringsrika släket innehåller växtbefrämjande ämnen och spelade en viktig roll i jordbruket på Gotland innan mineralgödsel introducerades. Idag spolas stora mängder släke upp på stränderna och det mesta läggs på hög utan att användas. Användning av släke som gödsel kan bidra till en minskning i extern input av näringsämnen till Östersjön och istället öka det cirkulära näringsflödet. Denna studie var en del av ett större projekt, drivet av KTH, vars syfte var att utvärdera släke som en potentiell bioresurs. Syftet med denna studie var att undersöka den effekt släkegödsling hade på rädisor och morötter för dess storlek och näringshalt, i jämförelse med NPK, i frilandsodling på Gotland. Efter att grödorna odlats och skördats bestämdes massan och mängden kolhydrater, pigment, huvudsakliga vitaminer och fettsyror för rot och blast för båda grödor. Resultatet visade en signifikant ökning i 1) massa i tre av fyra fall (alla utom för morötterna som låg precis under gränsen för 95% statistisk signifikans), 2) förhållandet i massa mellan rot/blast för rädisorna, 3) betakarotenkoncentration vitamin A och fettsyror för morötterna och 4) klorofyllkoncentration i blasterna för båda grödorna. Övriga observerade skillnader, utan statistiskt signifikans, var en ökning i massa för morötterna, ökad koncentration av anthocyanin i rädisorna, ökad koncentration av kolhydrater för morötter inklusive blast, minskad koncentration av kolhydrater för rädisor inklusive blast och slutligen en minskning i vitamin C koncentration för samtliga fyra fall. Användning av släke i form av gödsel gav grödorna en ökad massa och majoriteten av kvalitetsparametrarna överskreds eller var inom samma spann i jämförelse med grödor odlade med NPK. Användning av släke som komplement till mineralgödsel kan därför vara förmånligt för odlare, och bidrar samtidigt till en minskad extern input av näringsämnen till Östersjön.
8

Diagnosis of Loblolly Pine (Pinus taeda L.) Nutrient Deficiencies by Foliar Methods

Sypert, Robert Hall 02 November 2006 (has links)
Quick identification of loblolly pine nutrient deficiencies has troubled foresters who wish to increase productivity through fertilization. In the past, extensive field trials were established that did not allow for quick identification of a large number of possibly limiting nutrients in individual stands. This study used single-tree fertilization with macro-nutrients (N, P, K, Ca, Mg, S) and micro-nutrients (Mn, Zn, B, Cu, Fe, Mo) to identify deficiencies using foliar techniques in one growing season. Four study sites in TX, AL, GA, and SC were established in loblolly pine plantations at or near canopy closure. Nutrient concentrations relative to the critical level, optimal nutrient ratios, DRIS methodology, vector analysis, and changes in individual fascicle and total current year foliage weight/area were used to identify deficiencies. Phosphorus was repeatedly indicated as most limiting growth at TX while K was implicated at SC. The GA site revealed multiple deficiencies including N, K, and S. The AL site revealed only a very suspect B deficiency. Critical level methodology was effective in identifying deficiencies of N, P, and K, while B, S, and Cu appeared to be available at sufficient quantities when concentrations were below the published critical levels. Concentrations of S were especially below the critical levels and not increased by fertilization indicating that the critical levels were too high. Nutrient ratio interpretability was reduced by luxury uptake of N in comparison to other deficient nutrients. DRIS methodology was hampered by the inability to create effective comparative norms. Deficiency detection with vector analysis created problems when B and Mn displayed greater uptake relative to controls than the macro-nutrients that provided relative foliage mass increases. Resulting diagnosis indicated deficiencies when B and Mn were really taken up as luxury consumption. Vector analysis may not be as effective as its individual parts. Foliage weight/area responses detected fewer deficiencies than the other techniques. No significant foliar responses were seen at the TX or AL sites. However, K at the SC site was identified as deficient by all foliage mass variables, and multiple deficiencies were detectable at the GA site. / Master of Science
9

Implantação da piscicultura familiar com pescadores e agricultores assentados no Município de Lucena-PB

Marinho, Fabiana Bezerra 24 February 2011 (has links)
Made available in DSpace on 2015-05-07T14:49:14Z (GMT). No. of bitstreams: 1 parte1.pdf: 2218447 bytes, checksum: 089f22b3a430d6cd78b952e8351c0b9f (MD5) Previous issue date: 2011-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Fishing is a very important activity for the provision of protein, but as a result of the heavy pressure from extractive fishing and above the limits of carrying capacity of populations of commercial species, many stocks are at or above the limit of exploration, which has resulted in decreased populations of many animals, including driving some to extinction. As a result, aquaculture has increased worldwide, complementing the fisheries to obtain quality protein. By the increasing investment in this activity, it became one of the fastest growing economic activities worldwide, nowadays. Brazil is no different, and aquaculture has been growing over the years, and most fish cultures are being developed in freshwater ecosystems, and the crustacean culture in estuarine ecosystems. However, if this activity is not performed properly, can be quite impactant to natural ecosystems, as a result of the addition of nutrients, leading to eutrophication. In addition, breeding has been mostly with exotic species, which when they arrive in the natural habitat suppress native species, leading to the decreasing in local biodiversity. Antibiotics and other crops and products placed in the diets also end up interfering with the water quality of natural systems. Therefore, it is important that aquaculture should be promoted, as a promising economic activity, with capacity for growth in Brazil, and if it is practiced at the household level could contribute to the economic growth of traditional communities or poor ones, thus contributing to the local sustainable development. Thus, the aim of this thesis was to implement a training course for fishermen of Lucena and Fagundes beaches and farmers living in three settlements in Lucena municipality, so that they could further develop this activity in a sustainable manner. For that, ecological methods, such as horticultural waste recovery and preparation of alternative feeds for the reduction of production costs, were applied. The whole process was conducted in the form of action research among researchers and participants in the extension project PROEXT 2008, funded by the MEC / SESU. The course showed how to cultivate two fish species, carp and Nile tilapia, in a polyculture system. The results of this activity were very promising, the participants enjoyed the experience and showed interest in continuing by their own later. All the course members made all the activities, from the excavation of ponds until removal of the fishes. This study had shown that they can work successfully in teams, which they did not believe at first. The performance of the fish along the cultivation revealed that the alternative diet promoted a better growth performance of carp development, but a lower growth in tilapia. The nutrient analysis of the two diets, commercial and alternative, showed that the protein content was higher in commercial feed, which may have caused the difference in tilapia growth. Moreover, the economic analysis of cultivation with the two diets showed that the profit was very similar in the two analyzed ponds, due the lower feed cost of the alternative ration. The course has proved a success, and the participants learned to practice the procedures for aquaculture, being able to play all the activities learned and can thus diversify production on the properties and the fishermen, if they get a local for cultivation, depend less on fish stocks, thus ensuring greater security for their maintenance and cause a less pressure over species in the environment, allowing them to recover. / A pesca é uma atividade muito importante para a obtenção de alimentos protéicos, mas em conseqüência da grande pressão do extrativismo e da captura acima dos limites da capacidade de suporte das populações de espécies comerciais, muitos estoques estão no limite de exploração ou acima deste, o que tem resultado na diminuição de muitas populações de animais, inclusive levando algumas ao risco de extinção. Em virtude disso, a aqüicultura tem aumentado em todo o mundo, complementando a pesca para a obtenção de proteína de qualidade. Pelo maior investimento nesta atividade, esta tornou-se uma das atividades econômicas que mais cresce no mundo atualmente. No Brasil não é diferente, e a aqüicultura vem crescendo ao longo dos anos, sendo a piscicultura mais praticada em ecossistemas fluviais, e a carcinocultura em ecossistemas estuarinos. No entanto, se esta atividade não for realizada de forma adequada, poderá ser bastante impactante aos ecossistemas naturais, em conseqüência da adição de nutrientes, levando-os à eutrofização. Assim sendo, é importante que a aqüicultura seja incentivada, por ser uma atividade econômica promissora, com capacidade de crescimento no Brasil, e que se praticada a nível familiar poderá contribuir com o crescimento econômico de comunidades tradicionais ou carentes, contribuindo assim, com o desenvolvimento sustentável local. Desta forma, o objetivo desta dissertação foi o de participar de um curso de capacitação para pescadores das praias de Lucena e Fagundes e agricultores residentes em 2 assentamentos no município de Lucena, de forma a que eles pudessem futuramente desenvolver esta atividade de forma sustentável. Para isso, metodologias ecológicas, como o aproveitamento de resíduos hortifrutigranjeiros e a preparação de rações alternativas, para o barateamento da produção, foram aplicadas. Todo o processo foi realizado na forma de pesquisa-ação entre os pesquisadores e os participantes do projeto de extensão PROEXT 2008, financiado pelo MEC/SESU. O curso mostrou como cultivar duas espécies de peixe em policultivo, a carpa e a tilápia nilótica. Os resultados da atividade foram bastante promissores, os participantes gostaram da experiência e mostraram interesse em continuar. Todos os integrantes do curso realizaram todas as atividades, desde a escavação dos viveiros até a despesca. Ao mesmo tempo, com este trabalho foi possível verificar que eles podem trabalhar em equipe com sucesso, o que eles não acreditaram muito no início. O desempenho dos peixes ao longo do cultivo revelou que a ração alternativa promoveu um melhor desempenho no crescimento da carpa, mas um crescimento menor na tilápia. A análise bromatológica das duas rações, a comercial e a alternativa, revelou que o teor de proteínas foi mais elevado na ração comercial, o que pode ter causado essa diferença no crescimento das tilápias. Por outro lado, a análise econômica do cultivo com as duas rações mostrou que o lucro foi muito semelhante nos dois viveiros analisados, em virtude do menor custo da ração alternativa. A capacitação dos atores sociais revelou-se um sucesso, os participantes assimilaram a técnica da piscicultura, sendo capazes de reproduzir todas as atividades, podendo desta forma diversificar a produção nas suas propriedades, assim como, os pescadores, que se conseguirem local para o cultivo, dependerão menos dos estoques pesqueiros, podendo garantir com mais segurança o seu sustento e diminuindo ao mesmo tempo a superexploração das espécies de peixes no ambiente, permitindo a sua recuperação.
10

Host plant effects on the biology, behavior and ecology of brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae)

Acebes-Doria, Angelita L. 09 March 2016 (has links)
Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a polyphagous, invasive, and highly significant pest of mid-Atlantic fruit orchards. Its capacity to invade orchards season-long is believed to be facilitated by the availability of wild host plants near orchards and the high dispersal capacity of adults and nymphs. Interactions between H. halys and its hosts were investigated via laboratory and field experiments. Rearing H. halys nymphs in the laboratory on several of its known wild and tree fruit hosts used alone and in combination showed that peach was much more suitable for nymphal development and survival than was apple, tree of heaven, or catalpa and that nymphal performance was enhanced on mixed host diets. Nymphs reared on different host plant diets yielded adults that differed in protein, sugar or lipid content, offering new insights into plant diet effects on H. halys nutrition. The majority of tree species identified from unmanaged woodlands next to apple orchards in Virginia and West Virginia were known hosts of H. halys. Passive trunk traps were developed to capture H. halys nymphs walking up and down tree trunks and used to measure their temporal patterns of movement onto and off of wild and tree fruit hosts at the orchard-woodland interface via weekly assessments during two consecutive seasons. More upward- than downward-walking nymphs were captured, which may be partially explained by the positively phototactic and negatively geotactic behavior of H. halys nymphs demonstrated in laboratory studies. Most nymphs captured while walking up and down trunks were second instars, although the data also reflected temporal changes in the distribution of instars and temporal variation in the numbers of nymphs captured. A field study to characterize injuries to apple and peach fruit at harvest from feeding by young or older nymphs early or late in the season revealed that feeding by young nymphs early in the season resulted in least injury to both crops. In combination, these studies greatly improve our understanding of the biology and ecology of H. halys in eastern fruit orchards and provide relevant data that will inform the development of ecologically-based management programs for it. / Ph. D.

Page generated in 0.0897 seconds