832 resultados para operation system security mechanism


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The transmission of the transfusion-associated Chagas disease is an important mechanism of its dissemination in several Latin American countries. The transmission risk depends on five factors: prevalence of infection in blood donors, degree of serological coverage, sensibility of used tests, safety of obtained results and infection risk. The Southern Cone Iniciative set off by the Pan-American Health Organization, in 1991, is contributing to the implementation of blood law in each endemic country, and to reduce the risk of transfusional transmission of this horrible disease. Despite the clear improvement of Brasilian hemotherapy after 1980 (with the creation of the Blood National Program - Pró-Sangue) and the significant reduction of the chagasic infection among its blood donors; socio-economic, politic and cultural unlevels, prevent it from reaching the necessary universality and security. In order to assure both, the Brazilian Ministry of Health decided to restructure its blood system. In May, 1998, a great program was launched, to reach a specific goal: Blood - 100% with quality safety in all its process until 2003. It was divided in 12 projects, intends to guarantee the quality and self sufficiency in blood and hemoderivates.

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While mobile technologies can provide great personalized services for mobile users, they also threaten their privacy. Such personalization-privacy paradox are particularly salient for context aware technology based mobile applications where user's behaviors, movement and habits can be associated with a consumer's personal identity. In this thesis, I studied the privacy issues in the mobile context, particularly focus on an adaptive privacy management system design for context-aware mobile devices, and explore the role of personalization and control over user's personal data. This allowed me to make multiple contributions, both theoretical and practical. In the theoretical world, I propose and prototype an adaptive Single-Sign On solution that use user's context information to protect user's private information for smartphone. To validate this solution, I first proved that user's context is a unique user identifier and context awareness technology can increase user's perceived ease of use of the system and service provider's authentication security. I then followed a design science research paradigm and implemented this solution into a mobile application called "Privacy Manager". I evaluated the utility by several focus group interviews, and overall the proposed solution fulfilled the expected function and users expressed their intentions to use this application. To better understand the personalization-privacy paradox, I built on the theoretical foundations of privacy calculus and technology acceptance model to conceptualize the theory of users' mobile privacy management. I also examined the role of personalization and control ability on my model and how these two elements interact with privacy calculus and mobile technology model. In the practical realm, this thesis contributes to the understanding of the tradeoff between the benefit of personalized services and user's privacy concerns it may cause. By pointing out new opportunities to rethink how user's context information can protect private data, it also suggests new elements for privacy related business models.

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Public Policy and Ageing in Northern Ireland: Identifying Levers for Change Judith Cross, Policy Officer with the Centre for Ageing Research Development in Ireland (CARDI)��������Introduction Identifying a broad range of key public policy initiatives as they relate to age can facilitate discussion and create new knowledge within and across government to maximise the opportunities afforded by an ageing population. This article looks at how examining the current public policy frameworks in Northern Ireland can present opportunities for those working in this field for the benefit of older people. Good policy formulation needs to be evidence-based, flexible, innovative and look beyond institutional boundaries. Bringing together architects and occupational therapists, for example, has the potential to create better and more effective ways relevant to health, housing, social services and government departments. Traditional assumptions of social policy towards older people have tended to be medically focused with an emphasis on care and dependency. This in turn has consequences for the design and delivery of services for older people. It is important that these assumptions are challenged as changes in thinking and attitudes can lead to a redefinition of ageing, resulting in policies and practices that benefit older people now and in the future. Older people, their voices and experiences, need to be central to these developments. The Centre for Ageing Research and Development in Ireland The Centre for Ageing Research and Development in Ireland (CARDI) (1) is a not for profit organisation developed by leaders from the ageing field across Ireland (North and South) including age sector focused researchers and academics, statutory and voluntary, and is co-chaired by Professor Robert Stout and Professor Davis Coakley. CARDI has been established to provide a mechanism for greater collaboration among age researchers, for wider dissemination of ageing research information and to advance a research agenda relevant to the needs of older people in Ireland, North and South. Operating at a strategic level and in an advisory capacity, CARDI�۪s work focuses on promoting research co-operation across sectors and disciplines and concentrates on influencing the strategic direction of research into older people and ageing in Ireland. It has been strategically positioned around the following four areas: Identifying and establishing ageing research priorities relevant to policy and practice in Ireland, North and South;Promoting greater collaboration and co-operation on ageing research in order to build an ageing research community in Ireland, North and South;Stimulating research in priority areas that can inform policy and practice relating to ageing and older people in Ireland, North and South;Communicating strategic research issues on ageing to raise the profile of ageing research in Ireland, North and South, and its role in informing policy and practice. Context of Ageing in Ireland Ireland �۪s population is ageing. One million people aged 60 and over now live on the island of Ireland. By 2031, it is expected that Northern Ireland�۪s percentage of older people will increase to 28% and the Republic of Ireland�۪s to 23%. The largest increase will be in the older old; the number aged 80+ is expected to triple by the same date. However while life expectancy has increased, it is not clear that life without disability and ill health has increased to the same extent. A growing number of older people may face the combined effects of a decline in physical and mental function, isolation and poverty. Policymakers, service providers and older people alike recognise the need to create a high quality of life for our ageing population. This challenge can be meet by addressing the problems relating to healthy ageing, reducing inequalities in later life and creating services that are shaped by, and appropriate for, older people. Devolution and Structures of Government in Northern Ireland The Agreement (2) reached in the Multi-Party Negotiations in Belfast 1998 established the Northern Ireland Assembly which has full legislative authority for all transferred matters. The majority of social and economic public policy such as; agriculture, arts, education, health, environment and planning is determined by the Northern Ireland Assembly at Stormont. There are 11 Government Departments covering the main areas of responsibility with 108 elected Members of the Legislative Assembly (MLA�۪s). The powers of the Northern Ireland Assembly do not cover ��� reserved�۪ matters or ��� excepted�۪ matters . These are the responsibility of Westminster and include issues such as, tax, social security, policing, justice, defence, immigration and foreign affairs. Northern Ireland has 18 elected Members of Parliament (MP�۪s) to the House of Commons. Public Policy Context in Northern Ireland The economic, social and political consequence of an ageing population is a challenge for policy makers across government. Considering the complex and diverse causal factors that contribute to ageing in Northern Ireland, there are a number of areas of government policy at regional, national and international levels that are likely to impact in this area. International The Madrid International Plan of Action on Ageing (3) and the Research Agenda on Ageing for the 21st Century (4) provide important mechanisms for furthering research into ageing. The United Kingdom has signed up to these. The Madrid International Plan of Action on Ageing commits member states to a systematic review of the Plan of Action through Regional Implementation Strategies. The United Kingdom�۪s Regional Implementation Strategy covers Northern Ireland. National At National level, pension and social security are high on the agenda. The Pensions Act (5) became law in 2007 and links pensions increases with earnings as opposed to prices from 2012. Additional credits for people raising children and caring for older people to boost their pensions were introduced. Some protections are included for those who lost occupational pensions as a result of underfunded schemes being wound up before April 2005. In relation to State Pensions and benefits, this Act will bring changes to state pensions in future. The Act now places the Pension Credit element which is up-rated in line with or above earnings, on a permanent, statutory footing. Regional At regional level there are a number of age related public policy initiatives that have the potential to impact positively on the lives of older people in Northern Ireland. Some are specific to ageing such as the Ageing in an Inclusive Society (6) and others by their nature are cross-cutting such as Lifetime Opportunities: Governments Anti-Poverty Strategy for Northern Ireland (7). The main public policy framework in Northern Ireland is the Programme for Government: Building a Better Future, 2008-2011(PfG) (8) . The PfG, is the overarching high level policy framework for Northern Ireland and provides useful principles for ageing research and public policy in Northern Ireland. The PfG vision is to build a peaceful, fair and prosperous society in Northern Ireland, with respect for the rule of law. A number of Public Service Agreements (PSA) aligned to the PfG confirm key actions that will be taken to support the priorities that the Government aim to achieve over the next three years. For example objective 2 of PSA 7: Making Peoples�۪ Lives Better: Drive a programme across Government to reduce poverty and address inequality and disadvantage, refers to taking forward strategic action to promote social inclusion for older people; and to deliver a strong independent voice for older people. The Office of the First Minister and deputy First Minister (OFMDFM) have recently appointed an Interim Older People�۪s Advocate, Dame Joan Harbison to provide a focus for older peoples issues across Government. Ageing in an Inclusive Society is the cross-departmental strategy for older people in Northern Ireland and was launched in March 2005. It sets out the approach to be taken across Government to promote and support the inclusion of older people. The vision coupled with six strategic objectives form the basis of the action plans accompanying the strategy. The vision is: ���To ensure that age related policies and practices create an enabling environment, which offers everyone the opportunity to make informed choices so that they may pursue healthy, active and positive ageing.�۝ (Ageing in an Inclusive Society, Office of the First Minister and Deputy First Minister, 2005) Action planning and maintaining momentum across government in relation to this strategy has proved to be slower than anticipated. It is proposed to refresh this Strategy in line with Opportunity Age ��� meeting the challenges of ageing in the 21st Century (9). There are a number of policy levers elsewhere which can also be used to promote the positive aspects of an ageing society. The Investing for Health (10) and A Healthier Future:A 20 Year Vision for Health and Well-being in Northern Ireland (11), seek to ensure that the overall vision for health and wellbeing is achievable and provides a useful framework for ageing policy and research in the health area. These health initiatives have the potential to positively impact on the quality of life of older people and provide a useful framework for improving current policy and practice. In addition to public policy initiatives, the anti-discrimination frameworks in terms of employment in Northern Ireland cover age as well as a range of other grounds. Goods facilitates and services are currently excluded from the Employment Equality (age) Regulations (NI) 2006 (12). Supplementing the anti-discrimination measures, Section 75 of the Northern Ireland Act 1998 (13), unique to Northern Ireland, places a statutory obligation on public authorities in fulfilling their functions to promote equality of opportunity across nine grounds, one of which is age(14). This positive duty has the potential to make a real difference to the lives of older people in Northern Ireland. Those affected by policy decisions must be consulted and their interests taken into account. This provides an opportunity for older people and their representatives to participate in public policy-making, right from the start of the process. Policy and Research Interface ���Ageing research is vital as decisions in relation to policy and practice and resource allocation will be made on the best available information�۝. (CARDI�۪s Strategic Plan 2008-2011) As outlined earlier, CARDI has been established to bridge the gap to ensure that research reaches those involved in making policy decisions. CARDI is stimulating the ageing research agenda in Ireland through a specific research fund that has a policy and practice focus. My work is presently focusing on helping to build a greater awareness of the key policy levers and providing opportunities for those within research and policy to develop closer links. The development of this shared understanding by establishing these links between researchers and policy makers is seen as the best predictor for research utilization. It is important to acknowledge and recognise that researchers and policy makers operate in different institutional, political and cultural contexts. Research however needs to ���resonate�۪ with the contextual factors in which policy makers operate. Conclusions Those working within the public policy field recognise all too often that the development of government policies and initiatives in respect of age does not guarantee that they will result in changes in actual provision of services, despite Government recommendations and commitments. The identification of public policy initiatives as they relate to age has the potential to highlight persistent and entrenched difficulties that social policy has previously failed to address. Furthermore, the identification of these difficulties can maximise the opportunities for progressing these across government. A focus on developing effective and meaningful targets to ensure measurable outcomes in public policy for older people can assist in this. Access to sound, credible and up-to-date evidence will be vital in this respect. As well as a commitment to working across departmental boundaries to effect change. Further details: If you would like to discuss this paper or for further information about CARDI please contact: Judith Cross, Policy Officer, Centre for Ageing Research and Development in Ireland CARDI). t: +44 (0) 28 9069 0066; m: +353 (0) 867 904 171; e: judith@cardi.ie ; or visit our website at: www.cardi.ie References 1) Centre for Ageing Research and Development in Ireland (2008) Strategic Plan 2008-2011. Belfast. CARDI 2) The Agreement: Agreement Reached in the Multi-Party Negotiations. Belfast 1998 3) Madrid International Plan of Action on Ageing. http://www.un.org/ageing/ 4) UN Programme on Ageing (2007) Research Agenda on Ageing for the 21st Century: 2007 Update. New York. New York. UN Programme on Ageing and the International Association of Gerontology and Geriatrics. 5) The Pensions Act 2007 Chapter 22 6) Office of the First Minister and deputy First Minister (2005). Ageing in an Inclusive Society. Belfast. OFMDFM Central Anti-Poverty Unit. 7) Office of the First Minister and deputy First Minister (2005). Lifetime Opportunities: Government�۪s Anti-Poverty and Social Inclusion Strategy for Northern Ireland. Belfast. OFMDFM Central Anti-Poverty Unit. 8) Northern Ireland Executive (2008) Building a Better Future: Programme for Government 2008-2011. Belfast. OFMDFM Economic Policy Unit. 9) Department for Work and Pensions, (2005) Opportunity Age: Meeting the Challenges of Ageing in the 21 st Century. London. DWP. 10) Department of Health, Social Services and Public Safety (DHSS&PS) (2002) Investing for Health. Belfast. DHSS&PS. 11) Department of Health, Social Services and Public Safety (DHSS&PS) (2005) A Healthier Future:A 20 Year Vision for Health and Well-being in Northern Ireland Belfast. DHSS&PS. �� 12) The Employment Equality (Age) Regulations (Northern Ireland) 2006 SR2006 No.261 13) The Northern Ireland Act 1998, Part VII, S75 14) The nine grounds covered under S75 of the Northern Ireland Act are: gender, religion, race, sexual orientation, those with dependents, disability, political opinion, marital status and age.

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Part One explores the background factors relating to new school establishment, outlines the views received as a result of consultation with the public and the New Schools Advisory Committee (NSAC) and reviews international practice in relation to establishment of new schools. The population of the country experienced an unprecedented increase in the past ten years. Despite the current economic downturn, the effect of this recent population increase is that growth in demand for school places is set to increase over the short to medium term. The overriding objective is to ensure that a school place is available to every child. Part Two explores issues around planning for new schools in the future. It discusses patron selection, the mechanism for identifying the need for a new school and proposals for cost effectiveness, including campus arrangements. A school is of central importance to a local community and therefore the establishment of a new school must be carried out with reference to the overall plan of the local authority for any given area. Guidelines published under Section 28 of the Planning Act entitled “The Provision of Schools and the Planning System” (July 2008) establish a 7 framework for co-operation between the Department and planning authorities to ensure the timely and cost-effective provision of school facilities.

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Autophagy is a cellular mechanism for degrading proteins and organelles. It was first described as a physiological process essential for maintaining homeostasis and cell survival, but understanding its role in conditions of stress has been complicated by the recognition of a new type of cell death ("type 2") characterized by deleterious autophagic activity. This paradox is important in the central nervous system where the activation of autophagy seems to be protective in certain neurodegenerative diseases but deleterious in cerebral ischemia. The development of new therapeutic strategies based on the manipulation of autophagy will need to take into account these opposing roles of autophagy.

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Consumer reviews, opinions and shared experiences in the use of a product is a powerful source of information about consumer preferences that can be used in recommender systems. Despite the importance and value of such information, there is no comprehensive mechanism that formalizes the opinions selection and retrieval process and the utilization of retrieved opinions due to the difficulty of extracting information from text data. In this paper, a new recommender system that is built on consumer product reviews is proposed. A prioritizing mechanism is developed for the system. The proposed approach is illustrated using the case study of a recommender system for digital cameras

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During the last decade the interest on space-borne Synthetic Aperture Radars (SAR) for remote sensing applications has grown as testified by the number of recent and forthcoming missions as TerraSAR-X, RADARSAT-2, COSMO-kyMed, TanDEM-X and the Spanish SEOSAR/PAZ. In this sense, this thesis proposes to study and analyze the performance of the state-of-the-Art space-borne SAR systems, with modes able to provide Moving Target Indication capabilities (MTI), i.e. moving object detection and estimation. The research will focus on the MTI processing techniques as well as the architecture and/ or configuration of the SAR instrument, setting the limitations of the current systems with MTI capabilities, and proposing efficient solutions for the future missions. Two European projects, to which the Universitat Politècnica de Catalunya provides support, are an excellent framework for the research activities suggested in this thesis. NEWA project proposes a potential European space-borne radar system with MTI capabilities in order to fulfill the upcoming European security policies. This thesis will critically review the state-of-the-Art MTI processing techniques as well as the readiness and maturity level of the developed capabilities. For each one of the techniques a performance analysis will be carried out based on the available technologies, deriving a roadmap and identifying the different technological gaps. In line with this study a simulator tool will be developed in order to validate and evaluate different MTI techniques in the basis of a flexible space-borne radar configuration. The calibration of a SAR system is mandatory for the accurate formation of the SAR images and turns to be critical in the advanced operation modes as MTI. In this sense, the SEOSAR/PAZ project proposes the study and estimation of the radiometric budget. This thesis will also focus on an exhaustive analysis of the radiometric budget considering the current calibration concepts and their possible limitations. In the framework of this project a key point will be the study of the Dual Receive Antenna (DRA) mode, which provides MTI capabilities to the mission. An additional aspect under study is the applicability of the Digital Beamforming on multichannel and/or multistatic radar platforms, which conform potential solutions for the NEWA project with the aim to fully exploit its capability jointly with MTI techniques.

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How many times a given process p preempts, either voluntarily or involuntarily, is an important threat to computer's processes throughput. Whenever running cpu-bound processes on a multi-core system without an actual system grid engine as commonly found on Grid Clusters, their performance and stability are directly related to their accurate implementation and the system reliability which is, to an extend, an important caveat most of the times so difficult to detect. Context Switching is time-consuming. Thus, if we could develop a tool capable of detecting it and gather data from every single performed Context Switch, we would beable to study this data and present some results that should pin-point at whatever their main cause could be.

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BACKGROUND Advanced heart failure (HF) is associated with high morbidity and mortality; it represents a major burden for the health system. Episodes of acute decompensation requiring frequent and prolonged hospitalizations account for most HF-related expenditure. Inotropic drugs are frequently used during hospitalization, but rarely in out-patients. The LAICA clinical trial aims to evaluate the effectiveness and safety of monthly levosimendan infusion in patients with advanced HF to reduce the incidence of hospital admissions for acute HF decompensation. METHODS The LAICA study is a multicenter, prospective, randomized, double-blind, placebo-controlled, parallel group trial. It aims to recruit 213 out-patients, randomized to receive either a 24-h infusion of levosimendan at 0.1 μg/kg/min dose, without a loading dose, every 30 days, or placebo. RESULTS The main objective is to assess the incidence of admission for acute HF worsening during 12 months. Secondarily, the trial will assess the effect of intermittent levosimendan on other variables, including the time in days from randomization to first admission for acute HF worsening, mortality and serious adverse events. CONCLUSIONS The LAICA trial results could allow confirmation of the usefulness of intermittent levosimendan infusion in reducing the rate of hospitalization for HF worsening in advanced HF outpatients.

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Oleoylethanolamide (OEA) is an agonist of the peroxisome proliferator-activated receptor α (PPARα) and has been described to exhibit neuroprotective properties when administered locally in animal models of several neurological disorder models, including stroke and Parkinson's disease. However, there is little information regarding the effectiveness of systemic administration of OEA on Parkinson's disease. In the present study, OEA-mediated neuroprotection has been tested on in vivo and in vitro models of 6-hydroxydopamine (6-OH-DA)-induced degeneration. The in vivo model was based on the intrastriatal infusion of the neurotoxin 6-OH-DA, which generates Parkinsonian symptoms. Rats were treated 2 h before and after the 6-OH-DA treatment with systemic OEA (0.5, 1, and 5 mg/kg). The Parkinsonian symptoms were evaluated at 1 and 4 wk after the development of lesions. The functional status of the nigrostriatal system was studied through tyrosine-hydroxylase (TH) and hemeoxygenase-1 (HO-1, oxidation marker) immunostaining as well as by monitoring the synaptophysin content. In vitro cell cultures were also treated with OEA and 6-OH-DA. As expected, our results revealed 6-OH-DA induced neurotoxicity and behavioural deficits; however, these alterations were less severe in the animals treated with the highest dose of OEA (5 mg/kg). 6-OH-DA administration significantly reduced the striatal TH-immunoreactivity (ir) density, synaptophysin expression, and the number of nigral TH-ir neurons. Moreover, 6-OH-DA enhanced striatal HO-1 content, which was blocked by OEA (5 mg/kg). In vitro, 0.5 and 1 μM of OEA exerted significant neuroprotection on cultured nigral neurons. These effects were abolished after blocking PPARα with the selective antagonist GW6471. In conclusion, systemic OEA protects the nigrostriatal circuit from 6-OH-DA-induced neurotoxicity through a PPARα-dependent mechanism.

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This paper studies cooperation in a political system dominated by two opportunistic parties competing in a resource-based economy. Since a binding agreement as an external solution might be difficult to enforce due to the close association between the incumbent party and the government, the paper explores the extent to which co-operation between political parties that alternate in office can rely on self-enforcing strategies to provide an internal solution. We show that, for appropriate values of the probability of re-election and the discount factor cooperation in maintaining the value of a state variable is possible, but fragile. Another result is that, in such political framework, debt decisions contain an externality element linked to electoral incentives that creates a bias towards excessive borrowing.

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The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (AL:AR). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (AR) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (gs) and whole root system hydraulic conductance (kr) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψL) for Merlot grafted onto the 1103P root system (–0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (–1.06±0.03 MPa) during spring, but dropped by approximately –0.4 MPa from spring to autumn, and were significantly lower by –0.15 MPa (–1.43±0.02 MPa) than for Merlot on 101-14Mgt (at –1.28±0.02 MPa). Surprisingly, gs of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35–20 mmol vine−1 s−1 during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (kr) increased from 0.004 to 0.009 kg MPa−1 s−1 during that same time period. The changes in kr could not be explained by xylem anatomy or conductivity changes of individual root segments. Thus, the manner in which drought tolerance was conveyed to the drought-sensitive clone appeared to arise from deep root proliferation during the hottest and driest part of the season, rather than through changes in xylem structure, xylem density or stomatal regulation. This information can be useful to growers on a site-specific basis in selecting rootstocks for grape clonal material (scions) grafted to them.

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We study the social, demographic and economic origins of social security. The data for the U.S. and for a cross section of countries suggest that urbanization and industrialization are associated with the rise of social insurance. We describe an OLG model in which demographics, technology, and social security are linked together in a political economy equilibrium. In the model economy, there are two locations (sectors), the farm (agricultural) and the city (industrial) and the decision to migrate from rural to urban locations is endogenous and linked to productivity differences between the two locations and survival probabilities. Farmers rely on land inheritance for their old age and do not support a pay-as-you-go social security system. With structural change, people migrate to the city, the land loses its importance and support for social security arises. We show that a calibrated version of this economy, where social security taxes are determined by majority voting, is consistent with the historical transformation in the United States.

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Résumé de la thèseBien que le mutualisme puisse être considéré comme une relation harmonieuse entre différentes espèces, son étude révèle plutôt une exploitation réciproque où chaque partenaire tente de maximiser ses bénéfices tout en réduisant ses coûts. Dans ce contexte, l'identification des facteurs qui favorisent ou contrarient, au cours de l'évolution, une issue mutualiste est une étape majeure pour pouvoir reconstruire les étapes clés menant à l'apparition et au maintien des interactions mutualistes. Le but de ce doctorat était l'identification des traits phénotypiques qui permettent à la plante Silene latofolia (Caryophyllacée)et à son pollinisateur - prédateur de graines, la phalène Hadena bicruris (Noctuidé), d'augmenter les bénéfices nets que chacun retire de l'interaction. Ce système d'étude est particulièrement bien approprié à l'étude de ces traits, car on peut assez facilement estimer la qualité et la quantité des descendants (fitness) des deux partenaires. En effet, la femelle papillon pond un oeuf dans la fleur qu'elle pollinise et sa larve se développe dans le fruit, consommant les graines de la plante. Ainsi, sur une même plante, il est possible d'estimer les succès respectifs de la plante et du papillon à obtenir une descendance. De plus, le conflit d'intérêt autour des graines qui sont indispensables, à la fois à la plante et au papillon, peut stimuler l'évolution de traits qui limitent la surexploitation réciproque des partenaires. Dans une première étude, j'ai montré que le papillon mâle était un pollinisateur efficace de S. latifolia et qu'ainsi, il permettait à la plante d'augmenter le nombre de graines produites (i.e.bénéfice) sans pour autant augmenter la quantité de larves sur la plante. Dans ce système, les papillons pondent un seul oeuf par fleur, déposé soit à l'intérieur de la fleur, dans le tube de corolle, soit sur le pétale. Ma seconde étude montre que les plantes répondent différemment à la présence des oeufs suivant leur position. Aussi, quand l'oeuf est placé dans la fleur, la plante a davantage tendance à ne pas développer le fruit de la fleur infesté ou bien à produire des fruits plus petits que lorsque l'oeuf est placé sur le pétale. Enfin, j'ai montré que la femelle du papillon pond plus souvent sur le pétale lorsque elle visite des fleurs dotées d'un long tube de corolle, et que les larves issues de ces oeufs ont moins de chances de réussir à pénétrer dans le fruit que les larves issues des oeufs placés à l'intérieur de la fleur. Aussi, la variation observée du site de ponte pourrait être causé par la morphologie de la fleur qui contraint le papillon à pondre sur le pétale. Vu dans leur ensemble, les résultats obtenus pendant ce doctorat suggèrent que la participation des mâles à la pollination, l'absence de développement des fruits et la profondeur du tube de corolle pourraient réduire les coûts que S. latifolia subit dans son interaction avec H. bicruris. Par ailleurs, je n'ai pas détecté de mécanismes qui permettraient au papillon de réduire les coûts que la plante pourrait lui imposer. La prochaine étape serait de déterminer l'effet des traits identifiés dans ce doctorat sur la fitness globale de la plante et du papillon pour estimer pleinement leur efficacité à réduire les coûts et à favoriser une issue mutualiste. De même, il faudrait évaluer l'effet de ces traits en populations naturelles pour identifier le rôle des facteurs environnementaux sur leur efficacité.AbstractAlthough mutualisms can be regarded as harmonious relationships between the interacting partners, they are best conceptualized as reciprocal exploitations in which each partner attempts to increase its own benefits and decrease its costs. To date, identifying the factors which promote or discourage mutualistic outcomes remains a major goal to reconstruct the ecological conditions leading to mutualisms. The aim of this PhD thesis was to identify phenotypic traits that may increase the net benefits of each partner in the interaction between the plant Silene latifolia (Caryophyllaceae) and its pollinator / seed predator, the moth Hadena bicruris (Noctuidae). This study system is particularly well suited because the fitness of both interacting species can be assessed. The female moth lays its egg in the flower it pollinated, and its offspring grows in the fruit, feeding on the seeds of the plant, which allows for the follow-up of both larva and fruit fates. Furthermore, the inherent conflict of interest over the seeds as plant progeny vs. larval resource may stimulate the evolution of traits that reduce overexploitation in both the moth and plant. In a first study, I show that male moths are efficient pollinators, hence increasing seed production without increasing oviposition. The contribution of male moths to pollination might thus improve the net benefits of the interaction for the host plant. Females of the H. bicruris moth lay a single egg per flower, and place it either inside the corolla tube or on the petal. My second study shows that plants are more likely to abort the infested flower or to produce a smaller fruit when the egg was experimentally placed inside the flower compared to plants that received an egg on the petal. Finally, female moths were found to lay their eggs more frequently on the petal when visiting a flower with a deep corolla tube, and larvae hatching from these eggs less likely to successfully attack the fruit. Variation in egg position on the flower may thus be the result of a constraint imposed by floral morphology. Overall, this PhD work suggests that the pollination by male moths, flower abortion, and deep corolla tube may efficiently reduce the costs experienced by S. latifolia in its interaction with H. bicruris. Interestingly, no apparent mechanism of costs reduction was detected for the moth. Further studies should focus on the effects of these traits (i) in the long term fitness of both the plant and the insect and (ii) their interactions with environmental factors (biotic and abiotic) that may affect their efficiency in natural populations.

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This report was prepared by a committee of city, county and state representatives. The committee met throughout 2002 with the purpose of reviewing and making recommendations to improve the efficiency and operation of Iowa's road and street system. This report is referenced in SF 451 and in Code Section 306.8A.