Cost-effective analysis of different algorithms for the diagnosis of hepatitis C virus infection

We compared the cost-benefit of two algorithms, recently proposed by the Centers for Disease Control and Prevention, USA, with the conventional one, the most appropriate for the diagnosis of hepatitis C virus (HCV) infection in the Brazilian population. Serum samples were obtained from 517 ELISA-positive or -inconclusive blood donors who had returned to Fundação Pró-Sangue/Hemocentro de São Paulo to confirm previous results. Algorithm A was based on signal-to-cut-off (s/co) ratio of ELISA anti-HCV samples that show s/co ratio ³95% concordance with immunoblot (IB) positivity. For algorithm B, reflex nucleic acid amplification testing by PCR was required for ELISA-positive or -inconclusive samples and IB for PCR-negative samples. For algorithm C, all positive or inconclusive ELISA samples were submitted to IB. We observed a similar rate of positive results with the three algorithms: 287, 287, and 285 for A, B, and C, respectively, and 283 were concordant with one another. Indeterminate results from algorithms A and C were elucidated by PCR (expanded algorithm) which detected two more positive samples. The estimated cost of algorithms A and B was US$21,299.39 and US$32,397.40, respectively, which were 43.5 and 14.0% more economic than C (US$37,673.79). The cost can vary according to the technique used. We conclude that both algorithms A and B are suitable for diagnosing HCV infection in the Brazilian population. Furthermore, algorithm A is the more practical and economical one since it requires supplemental tests for only 54% of the samples. Algorithm B provides early information about the presence of viremia.

Optimal Recycling Combination of Ash in South-East Finland

The present world energy production is heavily relying on the combustion of solid fuels like coals, peat, biomass, municipal solid waste, whereas the share of renewable fuels is anticipated to increase in the future to mitigate climate change. In Finland, peat and wood are widely used for energy production. In any case, the combustion of solid fuels results in generation of several types of thermal conversion residues, such as bottom ash, fly ash, and boiler slag. The predominant residue type is determined by the incineration technology applied, while its composition is primarily relevant to the composition of fuels combusted. An extensive research has been conducted on technical suitability of ash for multiple recycling methods. Most of attention was drawn to the recycling of the coal combustion residues, as coal is the primary solid fuel consumed globally. The recycling methods of coal residues include utilization in a cement industry, in concrete manufacturing, and mine backfilling, to name few. Biomass combustion residues were also studied to some extent with forest fertilization, road construction, and road stabilization being the predominant utilization options. Lastly, residues form municipal solid waste incineration attracted more attention recently following the growing number of waste incineration plants globally. The recycling methods of waste incineration residues are the most limited due to its hazardous nature and varying composition, and include, among others, landfill construction, road construction, mine backfilling. In the study, environmental and economic aspects of multiple recycling options of thermal conversion residues generated within a case-study area were studied. The case-study area was South-East Finland. The environmental analysis was performed using an internationally recognized methodology — life cycle assessment. Economic assessment was conducted applying a widely used methodology — cost-benefit analysis. Finally, the results of the analyses were combined to enable easier comparison of the recycling methods. The recycling methods included the use of ash in forest fertilization, road construction, road stabilization, and landfill construction. Ash landfilling was set as a baseline scenario. Quantitative data about the amounts of ash generated and its composition was obtained from companies, their environmental reports, technical reports and other previously published literature. Overall, the amount of ash in the case-study area was 101 700 t. However, the data about 58 400 t of fly ash and 35 100 t of bottom ash and boiler slag were included in the study due to lack of data about leaching of heavy metals in some cases. The recycling methods were modelled according to the scientific studies published previously. Overall, the results of the study indicated that ash utilization for fertilization and neutralization of 17 600 ha of forest was the most economically beneficial method, which resulted in the net present value increase by 58% compared to ash landfilling. Regarding the environmental impact, the use of ash in the construction of 11 km of roads was the most attractive method with decreased environmental impact of 13% compared to ash landfilling. The least preferred method was the use of ash for landfill construction since it only enabled 11% increase of net present value, while inducing additional 1% of negative impact on the environment. Therefore, a following recycling route was proposed in the study. Where possible and legally acceptable, recycle fly and bottom ash for forest fertilization, which has strictest requirements out of all studied methods. If the quality of fly ash is not suitable for forest fertilization, then it should be utilized, first, in paved road construction, second, in road stabilization. Bottom ash not suitable for forest fertilization, as well as boiler slag, should be used in landfill construction. Landfilling should only be practiced when recycling by either of the methods is not possible due to legal requirements or there is not enough demand on the market. Current demand on ash and possible changes in the future were assessed in the study. Currently, the area of forest fertilized in the case-study are is only 451 ha, whereas about 17 600 ha of forest could be fertilized with ash generated in the region. Provided that the average forest fertilizing values in Finland are higher and the area treated with fellings is about 40 000 ha, the amount of ash utilized in forest fertilization could be increased. Regarding road construction, no new projects launched by the Center of Economic Development, Transport and the Environment in the case-study area were identified. A potential application can be found in the construction of private roads. However, no centralized data about such projects is available. The use of ash in stabilization of forest roads is not expected to increased in the future with a current downwards trend in the length of forest roads built. Finally, the use of ash in landfill construction is not a promising option due to the reducing number of landfills in operation in Finland.

Le soutien parental à l’autonomie et l’honnêteté : le rôle médiateur de l’intériorisation de la valeur de l’honnêteté et de l’analyse coûts/bénéfices

Une communication honnête entre l’adolescent(e) et son parent est associée à un développement plus sain chez l’adolescent(e) (Stattin & Kerr, 2000). La présente étude s’intéresse à la façon dont les parents peuvent favoriser l’honnêteté chez leurs adolescents. En nous basant sur la Théorie de l’Autodétermination (Deci & Ryan, 2000), nous postulons que plus les parents soutiennent l’autonomie de leurs adolescents, plus ceux-ci sont honnêtes avec leurs parents. Nous postulons également qu’il y aurait deux variables médiatrices de cette relation : l’intégration de la valeur de l’honnêteté chez les adolescents ainsi que leur perception des coûts et des bénéfices vis-à-vis du fait d’être honnête avec leurs parents. Des analyses de modélisation par équations structurales se basant sur 174 dyades parent-adolescent ont démontré que plus les parents soutiennent l’autonomie de leurs adolescents, plus les adolescents intègrent la valeur de l’honnêteté et plus ils perçoivent des bénéfices élevés, et de faibles coûts, à être honnêtes avec leurs parents. L’intégration de la valeur de l’honnêteté et le fait de percevoir davantage de bénéfices que de coûts à être honnête prédisaient par la suite une communication plus honnête entre l’adolescent(e) et son parent. Le fait que le parent valorise l’honnêteté contribuait aussi à l’intégration de la valeur de l’honnêteté chez l’adolescent(e).

Effet de la classe ou expériences scolaires? : étude sur l'élaboration et la variation des aspirations scolaires réalistes des étudiant(e)s canadien(ne)s au regard des études universitaires

Cette thèse a été réalisée, entre autres, grâce à une subvention reçue du Fonds de recherche du Québec – Société et culture et de son partenaire le ministère de l’Éducation, du Loisir et du Sport (MELS) Les analyses contenues dans cette thèse ont été réalisées au Centre interuniversitaire québécois de statistiques sociales (CIQSS), membre du Réseau canadien des centres de données de recherche (RCCDR). Les activités du CIQSS sont rendues possibles grâce à l’appui financier du CRSHC, des IRSC, de la FCI, de Statistique Canada, du FRQSC ainsi que de l’ensemble des universités québécoises qui participent à leur financement. Les idées exprimées dans ce texte sont celles des auteurs et non celles des partenaires financiers.

The use of public participation and economic appraisal for public involvement in large-scale hydropower projects: Case study of the Nam Theun 2 Hydropower Project

Gaining public acceptance is one of the main issues with large-scale low-carbon projects such as hydropower development. It has been recommended by the World Commission on Dams that to gain public acceptance, publicinvolvement is necessary in the decision-making process (WCD, 2000). As financially-significant actors in the planning and implementation of large-scale hydropowerprojects in developing country contexts, the paper examines the ways in which publicinvolvement may be influenced by international financial institutions. Using the casestudy of the NamTheun2HydropowerProject in Laos, the paper analyses how publicinvolvement facilitated by the Asian Development Bank had a bearing on procedural and distributional justice. The paper analyses the extent of publicparticipation and the assessment of full social and environmental costs of the project in the Cost-Benefit Analysis conducted during the projectappraisal stage. It is argued that while efforts were made to involve the public, there were several factors that influenced procedural and distributional justice: the late contribution of the Asian Development Bank in the projectappraisal stage; and the issue of non-market values and discount rate to calculate the full social and environmental costs.

The role of subsidy in ensuring the sustainability of small-scale anaerobic digesters in Odisha, India

Small-scale anaerobic digester installation has been a development objective of the Indian government to provide rural households clean fuel. Anaerobic digester installation is heavily subsidised. Depending on caste, the rate of subsidy offered for the smallest system available (1m3) varies between 32.35% and 41.18% of the total installation price. Yet, there are gaps in knowledge regarding the usefulness of such subsidies from a sustainability perspective. A cost-benefit analysis was conducted to evaluate the circumstances required for digester sustainability. The analysis used household data collected from 115 cattle owning households in Odisha, India to evaluate profitability at three levels of subsidy (none, General caste subsidy, and Schedule Caste/Schedule Tribe subsidy). Additional analyses considered the effect of; taking a loan, replacing electric lighting with biogas lighting, and the wealth level of the household. The results indicated that access to subsidy improved profitability. Yet, profitability could be achieved without the use of subsidy. The level of benefit accrued by households was similar independent of wealth. However, the provision of subsidy was essential for ensuring profitability for those households required to take a loan to meet the expense of installation. Such findings highlight the importance of subsidy as a means of including the poor.

A influência do Banco Interamericano de Desenvolvimento na formulação de políticas públicas: análise das condições de financiamento do programa de reabilitação da área central do município de São Paulo - Procentro

Este trabalho analisa a atuação do Banco Interamericano de Desenvolvimento (BID) quanto ao financiamento de políticas públicas, notadamente o Programa de Revitalização do Centro de São Paulo (Procentro). O período observado se estende da administração Marta Suplicy (2000 – 2004) – gestão em que ocorreu a assinatura do contrato – à administração José Serra/Gilberto Kassab (2004 – 2008). Objetiva-se avaliar a influência exercida pelo BID numa política pública específica, tendo como referência o estudo de caso do Procentro. Para tanto, optou-se por realizar entrevistas em profundidade com alguns técnicos responsáveis por diferentes áreas do Programa, por analisar fontes documentais (contratos, programas e relatórios) com vistas a identificar o tipo de linguagem utilizada pelo Banco, assim como a qualidade de suas demandas e contrapartidas para a realização da referida política publica. As observações centraram-se nas etapas de pré-aprovação e no período da assinatura do contrato; portanto, nas fases entendidas como precondições e condições respectivamente. Constatou-se que as condicionalidades são pressupostos que condicionam a assinatura do Contrato, sendo este circunscrito a um instrumento de garantia de pagamento do empréstimo, o que implica a lógica do “custo-benefício” (o Banco considera apenas, portanto, os aspectos mensuráveis). Para tanto, o Banco exige um conjunto de procedimentos gerenciais que definem o modus operandi dos financiamentos, assim como estipula como padrão formas gerenciais conhecidas como “melhores práticas”. Quanto à análise das diferentes gestões político/partidárias, foi possível observar a opção do BID por não valorizar a participação popular, bem como ignorar as demandas reivindicadas pelos movimentos sociais representantes da população pobre. Ao analisar os documentos, observou-se que o BID possui uma visão particular em relação às políticas públicas baseando-se em modelos internacionais de experiências consideradas bem-sucedidas por ele. Por fim, os documentos assinados com os governos são de difícil acesso, o que denota baixa transparência.

Variabilidade genética entre populações de Pistia stratiotes

O manejo de plantas daninhas em ambientes aquáticos requer cuidado diferencial e específico, a fim de evitar a contaminação ou alteração nas funções dos corpos hídricos e otimização do custo-benefício das operações. O estudo das características genéticas de populações de plantas daninhas aquáticas fornece informações que podem auxiliar no seu controle e manejo. A alface-d'água é uma planta aquática flutuante livre amplamente distribuída em todo o Brasil, mas é em ambientes aquáticos eutrofizados que essa e outras espécies de rápido desenvolvimento causam problemas sociais e econômicos, devido à grande massa vegetal produzida. Este estudo caracterizou geneticamente populações de alface-d'água coletadas em 15 reservatórios de hidrelétricas (Barra Bonita-BAB, Bariri-BAR, Ibitinga-IBI, Chavantes-CHA, Salto Grande-SAG, Jurumirim-JUR, Promissão-PRO Jaguari-JAG, Nova Avanhandava-NAV, Mogi-Guaçu-MOG, Limoeiro-LIM, Três Irmãos-TRI, Ilha Solteira-ILS, Jupiá-JUP e Porto Primavera-PPR) do Estado de São Paulo. As análises foram realizadas no NUPAM (Núcleo de Pesquisas Avançadas em Matologia), ligado à FCA/UNESP, campus de Botucatu-SP. A técnica utilizada no estudo da diversidade genética foi o RAPD. Os materiais amostrados nos reservatórios do Estado foram muito similares em sua maioria. As populações de NAV, MOG, IBI, JUR, PRO e CHA foram idênticas geneticamente. BAB e SAG, LIM e TRI também foram muito parecidas, apresentando índice de distância genética de 0,0093 e 0,0178, respectivamente. A grande maioria dos reservatórios estudados (93%) apresentou distâncias inferiores a 0,30, formando um grupo definido. No entanto, a população de Jupiá, em média, foi a que apresentou maior diversidade genética (0,45).

Análise de processos alternativos na preparação de esqueletos para uso didático

Zoology laboratories at institutions of research and education have shown great demand for anatomical parts for practical lessons. However, although the bibliography is not necessarily scarce, analyses of the cost/benefit relations of such processes are rare, considering aspects such as preparation time, quality of the anatomical parts, and material and human resources. In addition to the common techniques already used, new low-cost products, not cited in literature and easily found in the market, were also tested. The main objective of this work was to elaborate and organize information on techniques of bone parts maceration for study collections, making comparative analyses on the cost/benefit relations of each technique. Twelve products were tested, evaluating experimental conditions such as: concentration and combination of reagents, temperature, pH and time of exposure of the parts to the reagents. The results indicated that the products recommended for the use in the maceration processes were: water, hydrogen peroxide and papaya juice (Carica papaya).

Low cost technology applied to thermometry of grains

Modern agriculture demands investments in technology that allows the farmers to improve productivity and quality of their products, aiming to establish themselves in a competitive market. However, the high costs of acquiring and maintaining such technology may be an inhibiting factor to its spread and acceptance, mainly to a large number of small grain Brazilian farmers, who need low cost innovative technological solutions, suitable for their financial reality. Starting from this premise, this paper presents the development of a low cost prototype for monitoring the temperature and humidity of grains stored in silos, and the economic implications of cost/benefit ratio of innovative applications of low cost technology in the process of thermometry of grains. The prototype was made of two electronic units, one for acquisition and another one for data reception, as well as software, which offered the farmers more precise information for the control of aeration. The data communication between the electronic units and the software was reliable and both were developed using low cost electronic components and free software tools. The developed system was considered as potentially viable to small grain Brazilian farmers; it can be used in any type of small silos. It provided reduction of costs of installation and maintenance and also offered an easy expansion system; besides the low cost of development when compared to similar products available in the Brazilian market.

Cost-effectiveness comparison between pituitary down-regulation with a gonadotropin-releasing hormone agonist short regimen on alternate days and an antagonist protocol for assisted fertilization treatments

Objective: To compare cost-effectiveness between pituitary down-regulation with a GnRH agonist (GnRHa) short regimen on alternate days and GnRH antagonist (GnRHant) multidose protocol on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcome. Design: Prospective, randomized. Setting: A private center. Patient(s): Patients were randomized into GnRHa (n = 48) and GnRHant (n = 48) groups. Intervention(s): GnRHa stimulation protocol: administration of triptorelin on alternate days starting on the first day of the cycle, recombinant FSH (rFSH), and recombinant hCG (rhCG) microdose. GnRHant protocol: administration of a daily dose of rFSH, cetrorelix, and rhCG microdose. Main Outcome Measure(s): ICSI outcomes and treatment costs. Result(s): A significantly lower number of patients underwent embryo transfer in the GnRHa group. Clinical pregnancy rate was significantly lower and miscarriage rate was significantly higher in the GnRHa group. It was observed a significant lower cost per cycle in the GnRHa group compared with the GnRHant group ($5,327.80 ± 387.30 vs. $5,900.40 ± 472.50). However, mean cost per pregnancy in the GnRHa was higher than in the GnRHant group ($19,671.80 ± 1,430.00 vs. $11,328.70 ± 907.20). Conclusion(s): Although the short controlled ovarian stimulation protocol with GnRHa on alternate days, rFSH, and rhCG microdose may lower the cost of an individual IVF cycle, it requires more cycles to achieve pregnancy. Clinical Trial Registration Number: NCT01468441. © 2013 by American Society for Reproductive Medicine.

An assessment of the economic impact of climate change on the Agriculture, Energy and Health sectors in Trinidad and Tobago

This report analyses the agriculture, energy, and health sectors in Trinidad and Tobago to assess the potential economic impacts of climate change on the sectors. The fundamental aim of this report is to assist with the development of strategies to deal with the potential impact of climate change on Trinidad and Tobago. It also has the potential to provide essential input for identifying and preparing policies and strategies to help advance the Caribbean subregion closer to solving problems associated with climate change and attaining individual and regional sustainable development goals. Some of the key anticipated impacts of climate change for the Caribbean include elevated air and sea-surface temperatures, sea-level rise, possible changes in extreme events and a reduction in freshwater resources. The economic impact of climate change on the three sectors was estimated for the A2 and B2 IPCC scenarios until 2050. An exploration of various adaptation strategies was also undertaken for each sector using standard evaluation techniques. The study of the impact of climate change on the agriculture sector focused on root crops, green vegetables and fisheries. For these sectors combined, the cumulative loss under the A2 scenario is calculated as approximately B$2.24 and approximately B$1.72 under the B2 scenario by 2050. This is equivalent to 1.37% and 1.05% of the 2008 GDP under the A2 and B2 scenarios, respectively. Given the potential for significant damage to the agriculture sector a large number of potential adaptation measures were considered. Out of these a short-list of 10 potential options were selected by applying 10 evaluation criteria. All of the adaptation strategies showed positive benefits. The analysis indicate that the options with the highest net benefits are: (1) Building on-farm water storage, (2) Mainstreaming climate change issues into agricultural management and (3) Using drip irrigation. Other attractive options include water harvesting. The policy decisions by governments should include these assessments, the omitted intangible benefits, as well as the provision of other social goals such as employment. The analysis of the energy sector has shown that the economic impact of climate change during 2011-2050 is similar under the A2 (US$142.88 million) and B2 (US$134.83 million) scenarios with A2 scenario having a slightly higher cost (0.737% of 2009 GDP) than the B2 scenario (0.695% of 2009 GDP) for the period. On the supply side, analyses indicate that Trinidad and Tobago’s energy sector will be susceptible to the climate change policies of major energy-importing countries (the United States of America and China), and especially to their renewable energy strategies. Implementation of foreign oil substitution policy by the United States of America will result in a decline in Trinidad and Tobago’s Liquefied Natural Gas (LNG) export (equivalent to 2.2% reduction in 2009 GDP) unless an alternative market is secured for the lost United States of America market. China, with its rapid economic growth and the highest population in the world, offers a potential replacement market for Trinidad and Tobago’s LNG export. In this context the A2 scenario will offer the best option for Trinidad and Tobago’s energy sector. The cost-benefit analysis undertaken on selected adaptation strategies reveal that the benefit-cost ratio of replacing electric water heaters with solar water heaters is the most cost-effective. It was also found that the introduction of Compact Fluorescent Light (CFL) and Variable Refrigerant Volume (VRV) air conditioners surpasses the projected cost of increased electricity consumption due to climate change, and provides an economic rationale for the adoption of these adaptation options even in a situation of increased electricity consumption occasioned by climate change. Finally, the conversion of motor fleets to Compressed Natural Gas (CNG) is a cost-effective adaptation option for the transport sector, although it has a high initial cost of implementation and the highest per capita among the four adaptation options evaluated. To investigate the effect of climate change on the health sector dengue fever, leptospirosis, food borne illnesses, and gastroenteritis were examined. The total number of new dengue cases for the period 2008 to 2050 was 204,786 for BAU, 153,725 for A2 and 131,890 for the B2 scenario. With regard to the results for leptospirosis, A2 and B2 seem to be following a similar path with total number of new cases in the A2 scenario being 9,727 and 9,218 cases under the B2 scenario. Although incidence levels in the BAU scenario coincided with those of A2 and B2 prior to 2020, they are somewhat lower post 2020. A similar picture emerges for the scenarios as they relate to food-borne illnesses and to gastroenteritis. Specifically for food-borne illnesses, the BAU scenario recorded 27,537 cases, the A2 recorded 28,568 cases and the B2 recorded 28,679 cases. The focus on the selected sources of morbidity in the health sector has highlighted the fact that the vulnerability of the country’s health sector to climate change does not depend solely on exogenously derived impacts, but also on the behaviour and practices among the population. It is clear that the vulnerability which became evident in the analysis of the impacts on dengue fever, leptospirosis and food-borne illnesses is not restricted solely to climate or other external factors. The most important adaptation strategy being recommended targets lifestyle, behaviour and attitude changes. The population needs to be encouraged to alter their behaviours and practices so as to minimise their exposure to harmful outcomes as it relates to the incidence of these diseases.

An assessment of the economic impact of climate change on the coastal and human settlements, tourism and transport sectors in Barbados

This report analyses the coastal and human settlements, tourism and transport sectors in Barbados to assess the potential economic impact of climate change on the sectors. The fundamental aim of this report is to assist with the development of strategies to deal with the potential impact of climate change on Barbados. Some of the key anticipated manifestations of climate change for the Caribbean include elevated air and sea-surface temperatures, sea-level rise, possible changes in extreme events and a reduction in freshwater resources. The economic impact of climate change on the three sectors was estimated for the A2 and B2 IPCC scenarios until 2050 (tourism and transport sectors) and 2100 (coastal and human settlements sector). An exploration of various adaptation strategies was also undertaken for each sector using standard evaluation techniques. The analysis has shown that based upon exposed assets and population, SLR can be classified as having the potential to create potential catastrophe in Barbados. The main contributing factor is the concentration of socioeconomic infrastructure along the coastline in vulnerable areas. The A2 and B2 projections have indicated that the number of catastrophes that can be classified as great is likely to be increased for the country. This is based upon the possible effects of the projected unscheduled impacts to the economy both in terms of loss of life and economic infrastructure. These results arise from the A2 and B2 projections, thereby indicating that growth in numbers and losses are largely due to socioeconomic changes over the projection period and hence the need for increased adaptation strategies. A key adaptation measure recommended is for the government of Barbados to begin reducing the infrastructure deficit by continuously investing in protective infrastructure to decrease the country’s vulnerability to changes in the climate. With regard to the tourism sector, it was found that by combining the impacts due to a reduction in tourist arrivals, coral reef loss and SLR, estimated total economic impact of climate change is US $7,648 million (A2 scenario) and US $5,127 million (B2 scenario). An economic analysis of the benefits and costs of several adaptation options was undertaken to determine the cost effectiveness of each one and it was found that four (4) out of nine (9) options had high cost-benefit ratios. It is therefore recommended that the strategies that were most attractive in terms of the cost-benefit ratios be pursued first and these were: (1) enhanced reef monitoring systems to provide early warning alerts of bleaching events; (2) artificial reefs or fish-aggregating devices; (3) development of national adaptation plans (levee, sea wall and boardwalk); (4) revision of policies related to financing carbon neutral tourism; and (5) increasing recommended design wind speeds for new tourism-related structures. The total cost of climate change on international transportation in Barbados aggregated the impacts of changes in temperature and precipitation, new climate policies and SLR. The impact for air transportation ranges from US$10,727 million (B2 scenario) to US$12,279 million (A2 scenario) and for maritime transportation impact estimates range from US$1,992 million (B2 scenario) to US$2,606 million (A2 scenario). For international transportation as a whole, the impact of climate change varies from US$12,719 million under the B2 scenario to US$14,885 million under the A2 scenario. Barbados has the institutions set up to implement adaptive strategies to strengthen the resilience of the existing international transportation system to climate change impacts. Air and sea terminals and facilities can be made more robust, raised, or even relocated as need be, and where critical to safety and mobility, expanded redundant systems may be considered.

Finite element methods for the Stokes system based on a Zienkiewicz type N-simplex

Hermite interpolation is increasingly showing to be a powerful numerical solution tool, as applied to different kinds of second order boundary value problems. In this work we present two Hermite finite element methods to solve viscous incompressible flows problems, in both two- and three-dimension space. In the two-dimensional case we use the Zienkiewicz triangle to represent the velocity field, and in the three-dimensional case an extension of this element to tetrahedra, still called a Zienkiewicz element. Taking as a model the Stokes system, the pressure is approximated with continuous functions, either piecewise linear or piecewise quadratic, according to the version of the Zienkiewicz element in use, that is, with either incomplete or complete cubics. The methods employ both the standard Galerkin or the Petrov–Galerkin formulation first proposed in Hughes et al. (1986) [18], based on the addition of a balance of force term. A priori error analyses point to optimal convergence rates for the PG approach, and for the Galerkin formulation too, at least in some particular cases. From the point of view of both accuracy and the global number of degrees of freedom, the new methods are shown to have a favorable cost-benefit ratio, as compared to velocity Lagrange finite elements of the same order, especially if the Galerkin approach is employed.

Aspetti di sostenibilità in agricoltura a diverse scale spaziali e temporali. Valutazioni ambientali, economiche ed energetiche.

La Tesi analizza le relazioni tra i processi di sviluppo agricolo e l’uso delle risorse naturali, in particolare di quelle energetiche, a livello internazionale (paesi in via di sviluppo e sviluppati), nazionale (Italia), regionale (Emilia Romagna) e aziendale, con lo scopo di valutare l’eco-efficienza dei processi di sviluppo agricolo, la sua evoluzione nel tempo e le principali dinamiche in relazione anche ai problemi di dipendenza dalle risorse fossili, della sicurezza alimentare, della sostituzione tra superfici agricole dedicate all’alimentazione umana ed animale. Per i due casi studio a livello macroeconomico è stata adottata la metodologia denominata “SUMMA” SUstainability Multi-method, multi-scale Assessment (Ulgiati et al., 2006), che integra una serie di categorie d’impatto dell’analisi del ciclo di vita, LCA, valutazioni costi-benefici e la prospettiva di analisi globale della contabilità emergetica. L’analisi su larga scala è stata ulteriormente arricchita da un caso studio sulla scala locale, di una fattoria produttrice di latte e di energia elettrica rinnovabile (fotovoltaico e biogas). Lo studio condotto mediante LCA e valutazione contingente ha valutato gli effetti ambientali, economici e sociali di scenari di riduzione della dipendenza dalle fonti fossili. I casi studio a livello macroeconomico dimostrano che, nonostante le politiche di supporto all’aumento di efficienza e a forme di produzione “verdi”, l’agricoltura a livello globale continua ad evolvere con un aumento della sua dipendenza dalle fonti energetiche fossili. I primi effetti delle politiche agricole comunitarie verso una maggiore sostenibilità sembrano tuttavia intravedersi per i Paesi Europei. Nel complesso la energy footprint si mantiene alta poiché la meccanizzazione continua dei processi agricoli deve necessariamente attingere da fonti energetiche sostitutive al lavoro umano. Le terre agricole diminuiscono nei paesi europei analizzati e in Italia aumentando i rischi d’insicurezza alimentare giacché la popolazione nazionale sta invece aumentando.