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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.
11

Vectors’ infecting ability modulation for Xylella fastidiosa invasions management in Italian olive orchards

Piccotti, Ugo 12 November 2023 (has links)
Recent estimates have revealed that more than 6.5 million olive trees in southern Italy have subdued to the Xylella fastidiosa infection, leading to the devasting Olive Quick Decline Syndrome (OQDS). This epidemic continues to expand, posing a significant threat to global olive oil production. OQDS has already resulted 30-34% reduction in ecosystem services provided by olive orchards and a 28% decline in associated biodiversity. Additionally, OQDS has annihilated productivity and the entire olive oil supply chain, causing considerable economic losses. To counteract the relentless spread of Xylella, Integrated Transmission Management (ITM) strategies are crucial. Reducing one vector per olive tree present in an olive orchard can confine X. fastidiosa within acceptable economic and environmental limits. Thus, monitoring and managing vector populations are crucial to curbing disease transmission. The complex interactions between insects and microorganisms are pivotal in the OQDS scenario. Understanding these interactions can provide insights into novel control strategies, such as disrupting bacterial symbiosis with Aphrophoridae foams, affecting the fitness of vector insects, and potentially reducing X. fastidiosa transmission. To counteract Xylella transmission effectively, biocontrol measures must be incorporated into IPM strategies for olive orchards. However, more than the current arsenal of vector antagonists is required. The entrance into the Europe of Zelus renardii shows promise in biocontrolling Xylella vectors. Furthermore, Z. renardii's ability to manage other olive pests adds to its utility. Zelus renardii's bionomics and its ability to regulate alarm pheromones via Brindley glands is crucial for its effective use in IPM strategies. The formulation of artificial diets for mass-rearing Z. renardii under controlled conditions can pave the way for its inundative release to enhance ITM. These biological and biotechnological control measures have the potential to significantly reduce Philaenus spumarius populations and the infective capacity of Xylella vectors within IPM strategies. This approach can also act preventively and protectively, reducing the risk of future infections and limiting repeated transmissions. Progress has been made in modulating the transmission abilities of Xylella vectors, while the challenge of OQDS and X. fastidiosa remains tricky. The availability of Z. renardii and exploring its capabilities offer a more sustainable and effective approach to managing this disease in olive production.
12

Pest risk analysis on hand luggage at OR Tambo International Airport : a case study of flights from Cameroon, India and Kenya

Ramasodi, Robert Mooketsa 11 February 2009 (has links)
A Pest Risk Analysis was conducted on commodities imported as hand luggage from Cameroon, India and Kenya at O.R. Tambo International Airport. The initiation phase indicated that fruit, and to a lesser extent vegetables, are often imported concealed in hand luggage and not declared for inspection. Such undeclared commodities pose a risk to the South African agricultural industry and environment as it may serve as a pathway for quarantine pests. The qualitative pest risk assessment conducted on the commodities intercepted indicated that the risk is high, with the commodities serving as pathways for quarantine pests including insects, bacteria, mites, fungi, viruses and weeds. Bactrocera fruit flies were identified as a specific high risk and were further subjected to a quantitative pest risk assessment. Mitigation treatments for fruit flies were evaluated for efficacy and effect on the quality of the fruit. Hot water immersion treatment was deemed to be an effective mitigation treatment for fruit flies. This treatment on fruit flies was found effective at pulp temp of 46°C and 47°C where the pulp temp is held for 10 and 12 minutes respectively. / Dissertation (MInstAgrar)--University of Pretoria, 2009. / Plant Production and Soil Science / unrestricted
13

The development and use of environmental health indicators for epidemiology and policy applications : a geographical analysis

Wills, John Trevelyan January 1998 (has links)
This thesis examines the development and use of environmental health indicators for epidemiology, risk assessment and policy applications from a geographical perspective. Although indicators have traditionally been used to examine temporal trends, the development of environmental health indicators (EHIs) may enable comparisons to be made between areas with contrasting environmental health conditions, support efforts to highlight ‘hot spots’ and facilitate the analysis of spatial patterns in environmental health conditions and health risk. The use of environmental health indicators is relatively new and little research has been conducted in this area. In the light of this, this thesis examines EHIs in the context of contemporary developments in environmental indicators, health-related and quality of life indicators, and indicators of sustainable development. Essential characteristics and requirements for EHIs are identified and the main areas of application are discussed. In the second part of the thesis, the development and use of Effis for evaluating exposure to traffic-related air pollution is examined, using GIS techniques. Potential indicators of exposure are identified and these are applied at a range of spatial scales, along with a number of additional measures. The results of this exercise show that although exposure to traffic-related air pollution is both difficult and costly to evaluate, proxy measures may be used. Pollutant concentrations, for example are frequently used to assess exposure, yet the lack of suitable data may also frequently preclude their use. Whilst other, cruder measures may be used, the relationship between these indicators, measured concentration and exposure is often uncertain. Consequently, EHIs for exposure to traffic-related air pollution may not provide a reliable indication of exposure and health risk. Their use in this area should therefore be undertaken with great caution and attempts made to validate specific measures prior to their use. At the same time, however, coarser ‘upstream’ indicators may provide relevant information in a policy context. For use in highlighting areas of concern, raising awareness about environmental health issues and encouraging policies which aim to improve environmental health conditions, ease of data collection and relation to policy may be more important than relation to specific health effects
14

An Agent-Based Model to Study the Spread and Control of Epidemics

Fuller, Ashley Dawn 01 January 2008 (has links)
The world continues to face outbreaks of disease due to natural causes as well as the threat of biological warfare. Mathematical modeling provides an avenue by which to predict and ultimately prevent widespread outbreaks. A wide variety of modeling tools have been used in the study of the spread of diseases, including Ordinary Differential Equations, Partial Differential Equations, and Difference Equations. In this study, an agent-based model is used to study the spread and control of epidemics and is based on Sirakoulis, et al. [1]. The computer program NetLogo [2] is used for simulation. The development and set-up procedures for this model are fully discussed. The model is used to study the effectiveness of vaccination and quarantine as methods of epidemic control. It is determined that the most effective means of controlling an epidemic is to quarantine individuals with symptoms. In addition, the effect of the adjacent contact coefficient in the model is examined and further development and uses of the model are discussed.
15

Estudo de tratamentos fitossanitários na manga (Mangífera indica L.) para exportação / Study of quarantine treatment in mango (Mangífera indica L.) for export

Cruz, Juliana Nunes da 13 May 2010 (has links)
O presente trabalho teve como objetivo verificar e comparar o comportamento químico e físico-químico da manga cv. Tommy Atkins submetida aos tratamentos hidrotérmico e a irradiação nas doses 0,4 kGy e 1,0 kGy, a fim de complementar os estudos feitos por SABATO et al (2009) no teste de transporte real de mangas irradiadas do Brasil para o Canadá. Esses estudos permitiram comparar o desempenho da irradiação com o tratamento térmico quanto à preservação das características da manga destinada à exportação. Para tanto as mangas foram divididas em grupos: controle; banho térmico (46°C por 90 min); dose 0,4 kGy e dose 1,0 kGy. Os frutos foram mantidos em câmara fria (11°C ± 2) por 14 dias, e, posteriormente, a temperatura ambiente (23°C ±2) até o fim de sua vida útil. Durante o período de armazenamento a baixa temperatura, as análise foram realizadas em intervalos de 7 dias; e a cada 3 dias, quando mantidos a temperatura ambiente. Os resultados indicaram que a dose de 1,0 kGy foi o único grupo que manteve os frutos com a coloração da casca no estágio 3 durante todo período do experimento, porém promoveu uma maior perda de textura e degradação nos teores de acidez total titulável nos frutos ainda verdes. Notou-se que somente o grupo controle apresentou teores mais altos de ácido cítrico e succínico no último dia de experimento. Não houve diferenças significativas nos valores de sólidos solúveis totais, açúcares totais e avaliação de massa fresca em relação aos tratamentos avaliados. A análise de observação visual indicou que o grupo do banho térmico foi o que obteve o maior número de descarte dos frutos por decomposição com, aproximadamente, 55%. Concluiu-se que a irradiação é mais efetiva para a preservação da qualidade de mangas cv. Tommy Atkins, diminuindo o surgimento de podridões ou murchamento em relação ao tratamento térmico. Entretanto, a preservação da qualidade extrínseca do fruto não é concomitantemente influenciada pelas suas características intrínsecas, uma vez que, internamente, os frutos continuam seu amadurecimento normal, independente da dose aplicada. / The purpose of the present study was to verify and compare the chemical and physical-chemical behaviour of mango cv. Tommy Atkins subjected to hydrothermal treatment and irradiation at doses 0.4 and 1.0 kGy, to complement the studies by SABATO et al (2009) in the real transport of irradiated mangoes from Brazil to Canada. These studies allowed to compare the performance of irradiation with heat treatment on the preservation of the characteristics of mango for export. For these reason fruits were divided into groups: control, heat bath (46 ° C for 90 min), at dose 0.4 kGy and at dose 1.0 kGy. The fruits were stored at low temperature (11 ° C ± 2) for 14 days, and then at room temperature (23 ° C ± 2) until the end of its useful life. During the period of cold storage the analysis were performed at intervals of 7 days and every 3 days when kept at room temperature. The results indicated that the dose of 1.0 kGy was the only group that kept the fruit with the skin color on stage 3 throughout the experimental period, but provided a greater loss of texture degradation and the levels of total acidity in the fruits with green skin. It was noted that only the control group showed higher levels of citric acid and succinic acid in the last day of the experiment. There were no significant differences in soluble solids, total sugars and evaluation of weight in relation to treatments. The analysis of visual observation indicated that the heat bath group was the one with the highest number of fruit drop by decomposition with approximately 55%. It was concluded that irradiation is more effective in preserving the quality of mangoes cv. Tommy Atkins, reducing the appearance of rot or shriveling in relation to heat treatment. However, the preservation of the skin of fruit is not concurrently influenced by its intrinsic nature, since, internally, the fruits continue their normal maturation, independent of the applied dose.
16

Spatial Quarantine : The Swedish quarantine system 1850-1894 and a spatial theoretical framework

Kaloteka, Karolina January 2019 (has links)
No description available.
17

Catching the flu : syndromic surveillance, algorithmic governmentality and global health security

Roberts, Stephen L. January 2018 (has links)
This thesis offers a critical analysis of the rise of syndromic surveillance systems for the advanced detection of pandemic threats within contemporary global health security frameworks. The thesis traces the iterative evolution and ascendancy of three such novel syndromic surveillance systems for the strengthening of health security initiatives over the past two decades: 1) The Program for Monitoring Emerging Diseases (ProMED-mail); 2) The Global Public Health Intelligence Network (GPHIN); and 3) HealthMap. This thesis demonstrates how each newly introduced syndromic surveillance system has become increasingly oriented towards the integration of digital algorithms into core surveillance capacities to continually harness and forecast upon infinitely generating sets of digital, open-source data, potentially indicative of forthcoming pandemic threats. This thesis argues that the increased centrality of the algorithm within these next-generation syndromic surveillance systems produces a new and distinct form of infectious disease surveillance for the governing of emergent pathogenic contingencies. Conceptually, the thesis also shows how the rise of this algorithmic mode of infectious disease surveillance produces divergences in the governmental rationalities of global health security, leading to the rise of an algorithmic governmentality within contemporary contexts of Big Data and these surveillance systems. Empirically, this thesis demonstrates how this new form of algorithmic infectious disease surveillance has been rapidly integrated into diplomatic, legal, and political frameworks to strengthen the practice global health security – producing subtle, yet distinct shifts in the outbreak notification and reporting transparency of states, increasingly scrutinized by the algorithmic gaze of syndromic surveillance.
18

Estudo de tratamentos fitossanitários na manga (Mangífera indica L.) para exportação / Study of quarantine treatment in mango (Mangífera indica L.) for export

Juliana Nunes da Cruz 13 May 2010 (has links)
O presente trabalho teve como objetivo verificar e comparar o comportamento químico e físico-químico da manga cv. Tommy Atkins submetida aos tratamentos hidrotérmico e a irradiação nas doses 0,4 kGy e 1,0 kGy, a fim de complementar os estudos feitos por SABATO et al (2009) no teste de transporte real de mangas irradiadas do Brasil para o Canadá. Esses estudos permitiram comparar o desempenho da irradiação com o tratamento térmico quanto à preservação das características da manga destinada à exportação. Para tanto as mangas foram divididas em grupos: controle; banho térmico (46°C por 90 min); dose 0,4 kGy e dose 1,0 kGy. Os frutos foram mantidos em câmara fria (11°C ± 2) por 14 dias, e, posteriormente, a temperatura ambiente (23°C ±2) até o fim de sua vida útil. Durante o período de armazenamento a baixa temperatura, as análise foram realizadas em intervalos de 7 dias; e a cada 3 dias, quando mantidos a temperatura ambiente. Os resultados indicaram que a dose de 1,0 kGy foi o único grupo que manteve os frutos com a coloração da casca no estágio 3 durante todo período do experimento, porém promoveu uma maior perda de textura e degradação nos teores de acidez total titulável nos frutos ainda verdes. Notou-se que somente o grupo controle apresentou teores mais altos de ácido cítrico e succínico no último dia de experimento. Não houve diferenças significativas nos valores de sólidos solúveis totais, açúcares totais e avaliação de massa fresca em relação aos tratamentos avaliados. A análise de observação visual indicou que o grupo do banho térmico foi o que obteve o maior número de descarte dos frutos por decomposição com, aproximadamente, 55%. Concluiu-se que a irradiação é mais efetiva para a preservação da qualidade de mangas cv. Tommy Atkins, diminuindo o surgimento de podridões ou murchamento em relação ao tratamento térmico. Entretanto, a preservação da qualidade extrínseca do fruto não é concomitantemente influenciada pelas suas características intrínsecas, uma vez que, internamente, os frutos continuam seu amadurecimento normal, independente da dose aplicada. / The purpose of the present study was to verify and compare the chemical and physical-chemical behaviour of mango cv. Tommy Atkins subjected to hydrothermal treatment and irradiation at doses 0.4 and 1.0 kGy, to complement the studies by SABATO et al (2009) in the real transport of irradiated mangoes from Brazil to Canada. These studies allowed to compare the performance of irradiation with heat treatment on the preservation of the characteristics of mango for export. For these reason fruits were divided into groups: control, heat bath (46 ° C for 90 min), at dose 0.4 kGy and at dose 1.0 kGy. The fruits were stored at low temperature (11 ° C ± 2) for 14 days, and then at room temperature (23 ° C ± 2) until the end of its useful life. During the period of cold storage the analysis were performed at intervals of 7 days and every 3 days when kept at room temperature. The results indicated that the dose of 1.0 kGy was the only group that kept the fruit with the skin color on stage 3 throughout the experimental period, but provided a greater loss of texture degradation and the levels of total acidity in the fruits with green skin. It was noted that only the control group showed higher levels of citric acid and succinic acid in the last day of the experiment. There were no significant differences in soluble solids, total sugars and evaluation of weight in relation to treatments. The analysis of visual observation indicated that the heat bath group was the one with the highest number of fruit drop by decomposition with approximately 55%. It was concluded that irradiation is more effective in preserving the quality of mangoes cv. Tommy Atkins, reducing the appearance of rot or shriveling in relation to heat treatment. However, the preservation of the skin of fruit is not concurrently influenced by its intrinsic nature, since, internally, the fruits continue their normal maturation, independent of the applied dose.
19

Daniel Defoe and the Analysis of Panic and Fear in "A Journal of the Plague Year"

Su, Jiunn-Yuh 09 July 2004 (has links)
Viruses are microscopic biological organisms offensive in nature. Human beings have been combating viruses since times remote. Some battles were won, but never the war. One of the most eminent and destructive epidemics throughout human history is the bubonic plague, better known as the Black Death. Since its first attack on human beings, the casualty count produced by the bubonic plague has been astronomical. The epidemics not only inflict damage physically, but also psychologically on human beings. It is remarkable how such nearly invisible agents can instill so much fear in humans. Daniel Defoe¡¦s A Journal of the Plague Year is a masterpiece in journalistic fiction which brings literature, microbiology, and human behavioral psychology together. The book simply describes scenes from the 1665 London bubonic plague attack through the eyes of a narrator amidst the turmoil. However, it also serves as a guide book to human behavior in desperate times. Defoe vividly describes the plague, the suffering, the horror, and most importantly, the society, the people, and their reactions. With the Journal, Defoe blurred the line between factual and fictitious writing. He wrote a fiction based on factual data which very probably served as a warning aimed at public awareness towards epidemics. Some suspect that the Journal was merely an instrument of government propaganda; whichever the case, this book still constitutes as a milestone in epidemic literature as well as journalistic fiction. This thesis aims mainly at analyzing the relationship between the plague and humans. It is interesting to observe how the plague changed human behavior and induced some of the most common flaws in human character out of deep fear: mutual distrust, paranoia, superstition, opportunism, madness, anger, and hostility. The fragility and vulnerability of the human psyche are exposed in epidemic times such as in the recent SARS outbreak. Unavoidably, the destructiveness of the plague makes it evil in human eyes. However, it is possible to discover the positive and constructive sides of the plague instead of just the negative attributes. People tend to rely on religion in seeking comfort, explanation, and spiritual support. There are people who devote themselves to religion as well as those who choose a different path. At the end of the discussion, we take a look at how religion plays an important role in counteracting the epidemics¡¦ delirious effect on human beings.
20

Movement Restriction Implications on Potential Welfare Slaughter for Texas High Plains Feedlots

Galli, Monica 2011 December 1900 (has links)
Foot and mouth disease (FMD) is regarded as one of the greatest biological threats to the U.S. livestock industry because of its potential to cause catastrophic economic damages and massive livestock depopulation. Current U.S. contingency plans call for "stamping out" of FMD. An integral component of a "stamping out" policy is movement restrictions. The main purpose for movement restrictions is to stop the spread of disease, but they also disrupt the agribusiness sector. Welfare slaughter, the depopulation of healthy quarantined animals, is a possibility if movement restrictions are kept in place for prolonged periods of time. Many studies have analyzed the economic consequences of alternative mitigation strategies, but generally these studies have ignored the costs that might arise because of movement restrictions affecting uninfected premises located within the quarantine zone. Ultimately this study seeks to improve preparedness in the event of a FMD outbreak. It does this by developing information for those formulating plans on the costs associated with movement restrictions regarding quarantined, uninfected large feedlots located in the Texas High Plains Region. To accomplish this objective two strategies were compared: an unrestricted feed strategy, where feed is allowed to be brought onto uninfected premises and finished cattle are sold; and a welfare slaughter strategy, where feed isn't allowed to be brought onto the uninfected premises so animals are depopulated. In addition, seasonal differences in total costs were examined. This study expanded on the High Plains Study conducted by M. Ward, L. Highfield, P. Vongseng, and M. Garner by using their epidemiological data combined with a cost accounting framework to estimate the total cost of each strategy. This study examined direct disease management costs (indemnity payments, feed costs, marketing costs, surveillance costs, cleaning and disinfecting costs, appraisal cost, euthanasia costs, and disposal costs). Overall, the unrestricted feed strategy was less expensive than the welfare slaughter strategy, costing on average $22.6 million compared to $48.5 million, respectively. Disease outbreak timing did impact the overall cost of both strategies. The results suggest the policy makers should strongly consider creating movement policies that address feed supply and finished cattle movement for uninfected large feedlots in prolonged quarantine zones; as such policies appear to reduce outbreak related costs for stakeholder and the U.S. government.

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