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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

Use of a Slow Release Triazone-Based Nitrogen Fertilizer on Lemon Trees

Wright, Glenn C., Peña, Marco A. 10 1900 (has links)
Trisert CB replaced conventional foliar applied low-biuret urea and liquid urea ammonium nitrate in a typical N fertilization regime, a urea triazone based N source. There was no yield decrease, change in fruit size or grade with the use of the Trisert CB. There were no differences in leaf P, K, Ca, Mg, Cu, Fe, Mn or Zn concentration. Occasionally, leaf N concentration of trees supplied with foliar applied Trisert CB was higher than that of the control treatment.
32

Organic Lemon Production

Zerkoune, Mohammed, Wright, Glenn, Kernz, David, McCloskey, William 02 1900 (has links)
This experiment was initiated in March 2000 to study the feasibility of growing organic lemon in the desert southwest of Arizona. A ten-acre field planted to lemons in 1998 was selected on Superstition sand at the Yuma Mesa Agricultural Research Center. The initial soil test in top 6 inches was 5 parts per million (ppm) NO₃⁻ and 4.9-PPM NaHCO₃⁻-extractable P. Soil pH was 8.7 in the top 6 inches. Seven treatments were applied in randomized complete block design repeated three times. The treatments were control, compost and clover, compost and perfecta, compost and steam, manure and clover, manure and perfecta and manure and steam Leaf tissue analysis indicated that nitrate level was significantly influenced by treatment. Organic insect control treatments for citrus thrips were as equally effective as the non-organic commercial standards.
33

Fresh produce retail – analysis of vertical coordination and procurement models in the central California lemon supply chain

Avedian, Nathan January 1900 (has links)
Master of Agribusiness / Department of Agricultural Economics / Aleksan Shanoyan / The fresh produce retail market is becoming increasingly competitive and the need to cut costs in order to invest in retail prices and innovations is critical. Seasonality of commodities cause market shoulders where retailers face increased prices and an insecure supply base with risk of being out of product. The implications of paying more than competitors or not having a product on the shelf can risk losing a customer’s business to a competitor. This thesis is an analysis of procurement strategies by retailers in the fresh produce industry, in order to maximize efficiency by reducing cost of goods and securing supply. Specifically, this thesis will analyze different procurement strategies for procuring lemons out of the California San Joaquin Valley. The analysis will compare traditional market buys vs a vertically integrated procurement model in which the retailer procures farm land and controls the commodity from farm to store shelf. While the fresh produce industry has had an evolution over the past century, models of procurement are not following other industries in advancements such as innovations from technology, genetics and sustainability. By advancing procurement models the industry has the potential to not only benefit farmers and retailers but also deliver the customer a fresher product at a reduced price. The objective of this project is to investigate the ways to minimize commodity costs for the retailer and gain security of supply by analyzing procurement strategies for procuring lemons from California. This project is intended to support the fresh produce supply chain and specifically the retailer to optimize their procurement model. To determine an optimal strategy this project will compare and contrast traditional market buys vs a vertically integrated strategy. This is to determine if vertically integrating this commodity in a retailer supply chain would result in a net reduction of cost. Also, this project will determine if security of supply is gained through vertical integration vs traditional market buys. This project will consider variables such as market prices, supply/demand, sustainability and other industry implications. The data examined includes retail pricing and costs, farm production and cost, property market values, and other variables and inputs. The methods of analyzing the data include profitability scenarios throughout multiple procurement models for retailers to determine an optimal procurment model. As a result of the data and methods it is determined that there is an opportunity throughout the produce supply chain for retailers to shift away from traditional procurement models. This project’s proposed land acquisition procurement model is an alternative strategy that can supplement traditional procurement model and would potentially reduce cost of goods and improve supply reliability. This vertically integrated procurement model creates supply chain efficiencies and reduces cost for the retailer along with increasing the retailer's security of supply in the fresh produce commodity market. This analysis should serve as a basis and guide for retailers to determine their company’s optimal procurement model.
34

The Use of an Automatic Spot-Sprayer in Western Tree Crops and Weed Control in a Pecan Orchard Using Preemergence and Postemergence Herbicides

Rector, Ryan Jeffery January 2007 (has links)
Weed control is typically achieved by broadcast spraying postemergence herbicides on the entire orchard floor which wastes chemical by spraying bare ground. Growers can account for spatial variation in weed density and only spray weedy areas instead of applying herbicide to entire fields by using the automatic spot-sprayer, WeedSeeker sprayer. We conducted field experiments in flood- and microsprinikler-irrigated lemon orchards, and flood- and sprinkler-irrigated pecan orchards to measure the amount of herbicide applied, weed control, tree yield, and the economic value of adopting the WeedSeeker sprayer compared to conventional boom spray technology. The WeedSeeker sprayer reduced cumulative herbicide use by at least 36% compared to the conventional boom sprayer at all sites. Weed control obtained using the WeedSeeker sprayer was usually similar to the conventional boom sprayer. There were no effects of the treatments on yield at any location. The partial budget analysis, used to determine the economic value of adopting the technology, showed that as the area of the orchard and the cost of the herbicide increased, the time to recover the initial investment in the WeedSeeker sprayer decreased. The investment in the technology can typically be recovered in less than five years in Arizona lemon and pecan orchards.We also conducted greenhouse experiments to determine the effect of various sensitivity settings and leaf area on the operational efficiency of the WeedSeeker sprayer. The WeedSeeker sprayer did not detect and spray all broadleaf and monocot plants unless a sensitive setting was used. The WeedSeeker sprayer was more efficient when detecting broadleaf plants compared to monocot plants. Our results indicate that operating the WeedSeeker sprayer using a sensitive setting (sensitivity level 2) will result in the most efficient detection of weeds.Finally, field studies were conducted in a non-bearing pecan orchard to evaluate weed management systems using various postemergence and preemergence herbicides. Most postemergence herbicides controlled the weed species present in the orchard. Tank mixing the herbicides generally resulted in greater control compared to applying them alone. All preemergence herbicides reduced the weed emergence compared to not using a preemergence herbicide. No pecan tree damage was observed in any treatment.
35

Anti-inflammatory Properties of Citrus Limonoids and Their Isolation and Characterization

Kim, Jin Hee 2011 December 1900 (has links)
This dissertation investigates the role of limonoids in inflammation to reduce risk of breast cancer and cardiovascular disease. Radical scavenging activity and apoptotic effects of extracts from lemon seeds were investigated in human breast adenocarcinoma (MCF-7) cells and non-malignant breast (MCF-12F) cells. The MeOH:water (80:20) extract showed the highest (29.1%, P < 0.01) inhibition of MCF-7 cells without affecting the non-malignant breast cells. Further, the purified and modified limonoids were screened for their cytotoxicity on estrogen receptor (ER)-positive (MCF-7) or ER-negative (MDA-MB-231) human breast cancer cells. The MCF-7 cell was more susceptible to tested limonoids. Although most of limonoids induced anti-aromatase activity, the inhibition of proliferation was not related to the anti-aromatase activity. On the other hand, the anti-proliferative activity was significantly correlated with the level of caspase-7 activation by limonoids. The next study investigated the mechanism of anti-breast cancer and anti-aromatase activities of obacunone through inhibition of MCF-7 cell proliferation without affecting non-malignant breast cells. Treatment with obacunone resulted in an increased G1 cell cycle arrest and induction of apoptosis. Exposure of MCF-7 breast cancer cells to obacunone down-regulated expression of inflammatory molecules including nuclear factor-kappa B (NF--2 (COX-2). Furthermore, potential of obacunone on inhibition of COX-2 and NF-the p38 mitogen-activated protein (MAP) kinase was also investigated. In the final study, nomilin was the most potent natural inhibitor for p38 MAP kinase activity in human aortic smooth muscle cells indicating that a seven-membered A ring with acetoxy group, present in nomilin, seems to be essential for its inhibitory activity on p38 MAP kinase. The possible mechanism of nomilin for prevention of cardiovascular disease was determined. Pre-treatment with nomilin resulted in significant inhibition of TNF- induced HASMCs proliferation. The anti-proliferative activity of nomilin is due to apoptosis through mitochondrial dependent pathway.
36

The principal agent

Brusewitz Collin, Emanuel, Svensson, Andreas January 2014 (has links)
Problem: How can segments on Aktietorget explain how a lemon market can not only survive but grow? Purpose: The purpose is to try to explain how Aktietorget can grow under lemon market conditions by gauging investor groupings investment tendencies. Method: Quantitative archival study regarding returns and price per share depending on investor identity. Conclusion: Finance industry investor yields higher returns, which implicates the possibility of rational investing. This is attributed to either identity inherited capabilities or them being agents in the place of the principal. The private investor on the other hand is full principals and has a tendency towards low price per share. All other capital on Aktietorget conforms to the lottery characteristics of Aktietorget.
37

A History of Establishment Clause Jurisprudence With Respect to Parochial School Funding

Noonan, Peter James 11 January 2011 (has links)
Since the drafting of the Establishment Clause, a pronouncement contained within the First Amendment of the United States Constitution. The United States Supreme Court has debated how to interpret the meaning of, "Congress shall make no law respecting an establishment of religion." In Everson v. Board of Education (1947), the Court took its first action in an Establishment Clause case concerning funding for parochial school students that set a course that has been marked by confusion in the Court, inconsistent decision-making, and ultimately the creation of a policy of accommodation that provides opportunities for parochial school students to receive public financial assistance, including tuition reimbursement for their attendance at parochial schools. This study tracks the history of Establishment Clause jurisprudence with a research emphasis from Everson v. Board of Education (1947) to Zelman v. Simmons-Harris (2002) and illustrates how the philosophy of the United States Supreme Court has changed over time. Further context of the shift is provided with a discussion of the Lemon v. Kurtzman (1971) decision that served as an effective court-interpreted barrier to the use of public resources and funds for parochial schools for several years. Subsequent U.S. Supreme Court decisions have eroded gradually the barrier, coined the Wall of Separation between Church and State by Thomas Jefferson, culminating currently with Zelman v. Simmons-Harris (2002). The purpose of the study is to analyze the aforementioned shift in the context of public funding flowing for private church schools. It became clear through this study that the decision in Everson v. Board of Education was the decision which led to a history of conflict and confusion in the Court which set off a chain of events that ultimately led to public funding for parochial schools where allowable by State Constitution. The U.S. Supreme Court has determined that public funding for a sectarian school is allowable so long as the funding is neutral and at the personal discretion of the parents receiving it as opposed to directly supporting a sectarian school. / Ed. D.
38

Uso de colírios à base de Citrus lemon no reparo de úlcera de córnea induzida em coelhos : avaliação clínica, histomorfométrica e imuno-histoquímca /

Perches, Cintia Sesso. January 2011 (has links)
Orientador: Cláudia Valéria Seullner Brandão / Banca: José Joaquim Titton Ranzani / Banca: Alexandre Lima de Andrade / Resumo: O objetivo do presente estudo foi avaliar e comparar por meio de exames oftalmológicos, histopatológicos e imuno-histoquímica para PCNA, o processo de reparação corneal de úlceras superficiais induzidas em coelhos, frente à utilização de colírios de óleo essencial de Citrus lemon, produto até então não utilizado em oftalmologia. Foram utilizadas 50 fêmeas da espécie leporina, todas submetidas à indução da úlcera superficial, constituindo-se 5 grupos experimentais de 10 animais cada. Em três grupos foram instilados colírios à base de óleo essencial de Citrus lemon, em diferentes concentrações, sendo 1,5% (GL1,5), 3% (GL3) e 5% (GL5). O grupo controle (GC) recebeu substituto da lágrima, e o grupo Tween 80 8% (GT) foi tratado com o diluente utilizado na produção dos colírios de citrus. Todos os protocolos foram realizados quatro vezes ao dia. Os grupos foram divididos, aleatoriamente, em dois subgrupos, de acordo com o período final de avaliação, sendo M1, coelhos avaliados após 24 horas, e M5, após 5 dias. Não houve diferença entre os tratamentos utilizados quanto aos sinais clínicos secreção ocular, hiperemia conjuntival, quemose e opacidade corneal. O grupo tratado com colírio de óleo essencial de Citrus lemon na concentração 1,5%, no período final de avaliação, apresentou maior sensibilidade ocular em relação ao GC, além de aumento da celularidade corneal, representada principalmente por células inflamatórias. Nas comparações entre os momentos iniciais e finais, os grupos tratados com substituto da lágrima, Tween 80 8% e colírio à base de óleo essencial de Citrus lemon 5% promoveram aumento na espessura epitelial na periferia da córnea e maior percentual de proliferação celular, na avaliação final. Quanto à úlcera de córnea, houve redução significativa da extensão total para leve... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to evaluate and compare through ophthalmic exams, histopathology and immunohistochemistry for PCNA, the repair process in superficial corneal ulcers induced in rabbits using eyedrops of Citrus lemon essential oil, a product not used in ophthalmology yet. Fifty female rabbits were submitted to induction of the corneal ulcer and then divided into 5 experimental groups of 10 animals each. Were instilled into three groups eyedrops of Citrus lemon essential oil, in different concentrations, being 1.5% (GL1, 5), 3% (GL3) and 5% (GL5). The control group (CG) received a tear substitute, and the Tween 80 8% group (GT) was treated with the diluent used in the production of eyedrops of citrus. All protocols were performed four times a day. The groups were divided randomly into two subgroups, according to the final period of evaluation, in the M1 rabbits were evaluated after 24 hours, and in the M5 after 5 days. There was no difference between treatments for clinical signs: ocular discharge, conjunctival hyperemia, chemosis and corneal opacity. In the final period of evaluation, the group treated with eyedrops of Citrus lemon essential oil in the concentration 1.5% showed a higher ocular sensitivity compared to the GC, and increased of corneal cellularity, represented mainly by inflammatory cells. In the comparison between the initial and final moments, the groups treated with tear substitute, Tween 80 8% and eyedrops of Citrus lemon essential oil 5% led to an increase in epithelial thickness at the periphery of the cornea and a higher percentage of cell proliferation, in the final evaluation. In the clinical evaluation of corneal ulcer, there was significant reduction in total length for mild or absent at the time of final evaluation in all groups; the exception was GL 3%, that showed a lower... (Complete abstract click electronic access below) / Mestre
39

The cascade of physiological events leading to chilling injury : the effect of post-harvest hot water and molybdenum applications to lemon (citrus limon) fruit.

Mathaba, Nhlanhla. 01 November 2013 (has links)
New emerging markets such as Japan and the United States require cold sterilisation of South African citrus fruit as a phytosanitary standard against fruit fly. However, citrus fruit are chilling susceptible, with lemons being the second-most chilling susceptible after grapefruit. Chilling injury is a physiological rind disorder; the occurrence of which is despite its prevalence in horticultural commodities, not well understood. Therefore, the aim of this study was to investigate physiological compounds regulating chilling susceptibility or resistance in citrus fruit, with special emphasis on lemons. Furthermore, the potential of hot water dips or “molybdenum soaks” to maintain a certain level of physiological compounds which determine manifestation of chilling injury symptoms in citrus fruit was investigated. Moreover, it was attempted to create an understanding of the order in which physiological compounds mitigate chilling injury. Lemon fruit from different farms known to be chilling susceptible or resistant were obtained during the 2007 and 2008 harvest season. Thereafter, fruit were treated by soaking for 30 min in 1μM NaMo04.2H20 solution followed by a 2 min HWD 47 or 53°C. Treated fruit were waxed, weighed and stored at -0.5°C for up to 28 days and sampled for chilling injury evaluation 7, 14, 21, or 28 days into cold storage. A second evaluation was carried out five days after withdrawal from cold storage to allow development of chilling injury symptoms as a shelf-life simulation. After the second evaluation fruit were peeled, peel freeze-dried, milled using mortar and pestle and stored at -21°C for further physiological analysis. Freeze-dried peel was analysed for soluble sugars (glucose, fructose, sucrose), vitamin C (ascorbic acid), vitamin E (α-tocopherol), β-carotene, polyamines (putrescine, spermine, spermidine), specific flavanones (naringin and hesperidin) using HPLC-UV-Vis detector and proline, total antioxidant assays (FRAP, ABTS, DPPH), total phenolics, total flavonoids, lipid peroxidation using spectrophotometry, as well as for the heat shock protein (HSP70) using electrophoresis and silver-staining. Chilling susceptibility of lemon fruit varied with fruit source; those sourced from Ukulinga and Eston Estates were chilling resistant, while fruit from Sun Valley Estates showed chilling injury symptoms after 28 days of cold storage plus five days shelf-life. Furthermore, hot water dips (HW) 53°C, 1 μM Molybdenum (Mo) and 10 μM Mo plus HW 53°C significantly reduced chilling injury symptoms compared with the control and HW 47°C. In addition, Sun Valley Estates fruit also showed higher fruit weight loss compared with non-chilling resistant lemons. The alignment of higher fruit weight loss during storage with chilling susceptibility ascertains the use of weight loss as a non-destructive parameter for chilling susceptibility. With respect to flavedo sugars, glucose was found to be the dominant soluble sugar with multi-functional roles during cold storage. This plays a significant role in mitigating cellular stress. Chilling susceptible lemons from Sun Valley Estates had low flavedo glucose concentrations and, therefore, little conversion of glucose to ascorbic acid was possible resulting in a low antioxidant capacity. However, treatments with HW 53°C and Mo soaks seemed to enhance the enzymatic conversion of glucose to ascorbic acid leading to a higher antioxidant capacity in the flavedo of such treated fruit. Furthermore, glucose also feeds into the pentose phosphate pathway which is coupled with the shikimate pathway synthesizing secondary metabolites, especially of the phenolics group. The decrease in glucose was aligned to the levels of total phenolics, but not to that of β-carotene, naringin and hesperidin through 28 days into cold storage period. Moreover, as glucose also feeds into shikimate pathway, simultaneously an increase in proline flavedo concentration was observed. Proline is an antioxidant synthesized from glutamate; as cellular glucose decreases so does the total antioxidant capacity during cold storage. Ascorbic acid is a dominant and potent antioxidant in lemon flavedo as proven with the FRAP, ABTS and DPPH assays. Chilling resistant fruit have significantly higher ascorbic acid conversion. Furthermore, ascorbic acid also acts to generate the α-tocopheroxy radical to further important membrane-bound antioxidant, vitamin E (α-tocopherol equivalent). Furthermore, the DPPH assay was found to be effective in quantifying total antioxidants in lemon flavedo since it detects both lipophilic and hydrophilic antioxidants compared with the ABTS and FRAP assays which are bias to the estimation of liphophilic or hydrophilic antioxidants, respectively. The hot water and molybdenum treatments increased total antioxidants (DPPH assay) with reduced lipid peroxidation 7 days into cold storage and therefore, reduced chilling symptoms in fruit from Sun Valley Estates. The capacity of antioxidant to scavenge reactive oxygen species (ROS) was increased during cold storage and membrane stability significantly improved. Furthermore, putrescine as low valency polyamine was reduced as such compound acted as precursor to the synthesis of the high valency polyamines, spermine and spermidine. Chilling susceptible lemons from Sun Valley Estates showed increased soluble-conjugated polyamines as a response to stress. Furthermore, HW 53°C, 1 μM Mo and 10 μM Mo plus HW 53°C significantly increased the protein concentration and, therefore, likely also the occurrence of proteins with 70kDa (as estimator of HSP70). Additionally, the concentration of conjugated high valency polyamines was also increased, resulting in reduced chilling injury symptoms. The effect of ROS has only been viewed as damaging, while recently their role has also been viewed as stress acclamatory signalling compounds when produced concentrations below critical damaging threshold. Therefore, hot water dips seems to signals synthesis of total protein which include HSPs which then act throughout cold stress to protect other protein and channel other damaged proteins towards proteolysis. While molybdenum increased ROS production below damaging critical threshold, with ROS signalling stress acclimation by further signalling production of bioactive compound with antioxidant properties. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
40

Prey Selection by Young Lemon Sharks (Negaprion brevirostris) at Chandeleur Island Nursery Habitats with a Comparison to Three Other Co-Occurring Shark Species

Davis, Christopher 17 December 2010 (has links)
The Chandeleur Islands (Louisiana) contain nursery habitats for lemon sharks that provide abundant prey and protection from predation. Other local shark species (Atlantic sharpnose, bull, and blacktip sharks) co-occur with lemon sharks in the same region, including the nearby Biloxi Marshes. To better assess how lemon sharks use these nursery habitats, I measured diet and prey availability of young of the year and juvenile lemon sharks from 2009 to 2010. Young lemon sharks at the Chandeleur Islands have a relatively reduced diet breadth in comparison to those from nurseries in Bimini (Bahamas) and the Florida Keys. At the Chandeleur Islands, young lemon sharks appear to be opportunistically feeding on the most abundant prey items, resulting in high prey abundance and low diversity in their diet. Opportunistic feeding by young lemon sharks suggests minimal dietary overlap with other local shark species, resulting in minimal competition for resources.

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