130,741 research outputs found
Formação do espaço agroindustrial em Santa Catarina: o processo de produção de carnes do Oeste Catarinense
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-graduação em GeografiaNeste estudo, discute-se o processo de formação e representação do atual espaço agroindustrial de carnes de aves e suínos em SC, bem como suas principais características socioespaciais, tendo em vista o processo de ormação histórica, econômica, social e tecnológica. Nesse processo, as relações sociais estiveram permeadas pela presença de agentes hegemônicos que se beneficiaram com as condições gerais de produção implantadas em grande medida pelo Estado. Na divisão espacial da produção econômica brasileira, a Mesorregião Oeste de Santa Catarina constitui-se importante produtora de carnes de suínos e aves tendo por base a agricultura familiar e a produção integrada às grandes empresas agroindustriais. Essa produção teve origem já no início processo de colonização, entre as décadas de 1920 e 1940, quando os colonos criavam suínos para produzir banha. A criação desses animais era realizada à medida que a família também produzia produtos de origem vegetal, permitindo assim a diversificação na propriedade de forma autônoma. Com a integração, especialmente após a década de 1960, a relação dos produtores com as agroindústrias passou a ser marcada pela subordinação dos primeiros em relação a essas empresas. Os empresários agroindustriais tornam-se parte dos principais agentes hegemônicos regionais, inclusive na atualidade. No entanto, ao longo de todo o processo de formação da região agroindustrial, diferentes agentes contribuem para tornar desigual o espaço em questão, sendo os ervateiros, os madeireiros, os colonizadores, comerciantes e o Estado os principais agentes hegemônicos a conduzir essa formação. O Estado, por sua vez, teve participação efetivada pela viabilização de parte das condições gerais de produção # de uso coletivo # necessárias para que o capital se reproduzisse na região e fizesse desta a estrutura básica e também sua alavanca para, junto com os avanços tecnológicos do setor produtivo, conquistar o mercado nacional e externo com produtos a partir da suinocultura e da avicultura. Dans cette étude, il se discute le processus de formation et la représentation de l'actuel espace agro-industriel de viandes de volailles et de porcs dans Santa Catarina, ainsi que leurs principales caractéristiques socioespaciais, en vue du processus de formation historique, économique, sociale et technologique. Dans ce processus, les relations sociales ont été des permeadas par la présence d'agents hégémoniques qui se sont bénéficiés avec les conditions générales de production implantées dan économique brésilienne, à Mesorregião Ouest de Santa Catarina se constitue important producteur de viandes de porcs et de volailles en ayant par base l'agriculture familière et la production intégrée aux grandes sociétés agro-industrielles. Cette production a eu origine déjà dans le début processus de colonisation, entre les décennies de 1920 et 1940, quand les colons créaient des porcs pour produire baignent. La création de ces animaux était réalisée au fur et à mesure que la famille aussi produisait des produits d'origine végétale, en permettant ainsi la diversification dans la propriété de forme indépendante. Avec l'intégration, spécialement après la décennie de 1960, la relation des producteurs avec les agro-industries a passé à être marqué par la subordination de premiers concernant ces sociétés. Les entrepreneurs agro-industriels se rendent partie des principaux agents hégémoniques régionaux, de même dans l'actualité. Néanmoins, au long de tout le processus de formation de la région agro-industrielle, de différents agents contribuent pour rendre différent l'espace concerné, en étant les herbièrs, les marchands de bois, les colonisateurs, opérateurs et l'État les principaux agents hégémoniques à conduire cette formation. L'État, à son tour, a eu participation accomplie par la viabilisation de partie des conditions générales de production - d'utilisation collective - nécessaires pour que le capital se reproduise dans la région et faisait de la cette la structure basique et aussi son levier pour, conjointement les avances technologiques du secteur productif, conquérir le marché national et externe avec des produits à partir de la élevage de porcs et de l'aviculture
Optimal Bayesian sequential sampling rules for the economic evaluation of health technologies
No full textWe present a Bayes sequential economic evaluation model for health technologies in which an investigator has flexibility over the timing of a decision to stop carrying out research and to conclude that one technology is preferred to another on cost-effectiveness grounds. We implement the model by using an evaluation of the treatment of bacterial sinusitis and derive approximations of the optimal stopping rule as a function of accumulated sample size. We compare the performance of the model with existing frequentist and Bayes sequential designs and investigate the sensitivity of the stopping rule to changes in the parameters of the model. Our results suggest that accounting for the dynamic nature of experimentation, together with its economic parameters, should lead to greater efficiency in resource allocation within healthcare systems
R&D and market size: who benefits from orphan drug regulation?
No full textSince the early 80s, orphan drug regulations have been introduced to stimulate R&D for rare diseases. We develop a theoretical model to study the heterogeneous impact on optimal R&D decisions of the incentives for diseases with different levels of prevalence. We show the mechanisms through which the type of incentives deployed by orphan drug regulations may stimulate R&D more for orphan diseases with comparatively high prevalence, thus increasing inequality within the class of orphan diseases. Using data from the Food and Drug Administration on the number of orphan designations, our empirical analysis shows that, while R&D has increased over time for all orphan diseases, the increase has been much greater for the less rare. According to our baseline specification, the difference between the predicted number of orphan designations for a disease belonging to the highest and the lowest class of prevalence is 5.6 times larger after 2008 than it was in 1983. Our findings support the idea that the type of incentives in place may be responsible for this increase in inequality within orphan diseases
Aspetti critici negli studi clinici: problemi di metodo e applicazione
No full textA clinical study is useful to clarify some planned questions and it follows a well defined scheme (the study design). This PhD thesis has been divided in five main sections following a scheme guiding the reader in the analysis of critical aspects it's possible to find, first in data management, then in the study design and during the development and the final phases of a clinical study. Section A, Problems in database management, proposes a chapter about Record Linkage and a second chapter about Missing Values. Record Linkage consists in a series of statistical and data processing techniques for data integration and for the union of more datasets on the basis of patients' identifying variables. The problem of missing values is frequently present in a study: when a database contains missing values it's possible to turn to specific systems useful to calculate a suitable value for the unit without information, through statistical programs.
In section B, Study design, first clinical trials are analysed, then surveys are described and divided in cohort studies and case-control studies. In a cohort study (also called follow-up or prospective study) one or more groups of subjects are defined in accordance with the exposure to risk factors for one or more diseases, or not. Subjects are prospectively followed to study the disease(s) incidence and to observe if the disease(s) is(are) correlated with the etiological factors. A case-control study (or retrospective study) provides a research strategy to investigate possible factors preventing or causing a particular disease. The method implies a comparison between patients with the disease (cases) and a control group (healthy subjects). The comparison ends to find out factors which can be different in the two groups, explaining the presence of the disease in patients.
Section C concerns Variables treatment and Outcome variable classifications. In the first part, types of variables, their measurement scales, their reduction in indicators and their transformations are analysed. In the second part the classifications of the outcome variable is described. These classifications may regard a specific disease (ICD IX and X), the patient's symptoms (ICD) or a disease effect, i.e. an impairment, a disability or a handicap (ICIDH and ICF).
Sections D and E deal with choice of the multivariate analysis method. Section D aims to give a synthesis of the main analysis methods, dividing them in accordance with the variables symmetry. If there is a distinction between outcome variable and covariates, a multiple regression (stepwise or logistic) analysis method is suggested; discriminant analysis is useful if there are more outcome variables. If variables are all on the same level, factors analysis, principal components analysis, correspondences analysis and cluster analysis are proposed in conformity with the specific analysis aims. In section E logistic regression analysis is developed, pointing out the main aspects and considering the conditional logistic regression analysis for a Matched Case-Control Study design.
Every chapter is organized in two parts: in the first one a synthesis of theory and practical methods are given to explain how literature deals with the specific problem in a clinical study; in the second one a specific application is presented to show how the author solved the methodology problems in a particular clinical-genetic study carried out at the Children's Hospital of Oulu University - Finland. In this Institute a substantial work on a preterm infants database creation has been performed. The database collected all the clinical and genetic information about preterm infants born in one of the three main hospitals in Northern-central Finland, Oulu, Tampere and Seinäjoki. Through this final database containing all patients from the three hospitals, a clinical-genetic case-control study (match 1-1) on the association between Respiratory Distress Syndrome (RDS) and single nucleotide polymorphisms (SNPs) has been carried out using a conditional logistic regression analysis. The project was directed by Prof. M. Hallman
R&D and market size : Who benefits from orphan drug legislation?
No full textSince the early 80s, incentives have been introduced to stimulate R&D for rare diseases. We develop a theoretical model to study the impact of push and pull incentives on the intensive and extensive margin of optimal R&D investments. The model describes the mechanisms by which the type of incentives provided may favor R&D for orphan diseases with comparatively high prevalence. In our empirical analysis, we merge data on orphan drug designations by the Food and Drug Administration with Orphanet data on disease characteristics. In line with the theoretical results, we find evidence supporting the idea that the incentives adopted may have contributed substantially to widening the gap between more and less rare diseases classified as orphan. Our theoretical and empirical findings together suggest that, if providing some therapeutic option to patients with very rare diseases is a priority, a revision of the current system of incentives should be considered
The Dynamics of Pharmaceutical Regulation and R&D Investments
No full textThe paper uses a real option approach to investigate the properties of two widely used schemes of regulating the reimbursement of new pharmaceutical products: standard cost-effectiveness thresholds and performance-based risk-sharing agreements. The use of the latter has been quickly spreading and often criticized in recent times. The results show that the exact definition of the risk-sharing agreement is key in determining its economic effects. In particular, despite the concerns expressed by some authors, the incentive for a firm to invest in R&D may be the same or even greater than under cost-effectiveness thresholds. The greater flexibility on the timing of commercialization allowed by risk-sharing schemes plays a key role, by increasing the value of the option to invest in R&D under uncertainty. Under this scheme, a higher value for the firm is associated with earlier access to innovations for patients. The price for this is less value for money for the insurer at the time of adoption of the innovation
Optimal sequential sampling rules for the economic evaluation of health technologies
No full textReferring to the literature on optimal stopping under sequential sampling developed by Chernoff and collaborators, we present a dynamic model of the evaluation of a new health technology, deriving optimal rules for research abandonment and continuation and technology adoption as functions of sample size. We explore the model's applicability in a preliminary analysis of the economic evaluation of Drug Eluting Stents (DES). A key finding is that referring to a single cost-effectiveness threshold, irrespective of other economic dimensions to the decision, may be sub-optimal
3D Radiometric Mapping by Means of LiDAR SLAM and Thermal Camera Data Fusion
No full textThe ability to produce 3D maps with infrared radiometric information is of great interest for many applications, such as rover navigation, industrial plant monitoring, and rescue robotics. In this paper, we present a system for large-scale thermal mapping based on IR thermal images and 3D LiDAR point cloud data fusion. The alignment between the point clouds and the thermal images is carried out using the extrinsic camera-to-LiDAR parameters, obtained by means of a dedicated calibration process. Rover’s trajectory, which is necessary for point cloud registration, is obtained by means of a LiDAR Simultaneous Localization and Mapping (SLAM) algorithm. Finally, the registered and merged thermal point clouds are represented through an OcTree data structure, where each voxel is associated with the average temperature of the 3D points contained within. Furthermore, the paper presents in detail the method for determining extrinsic parameters, which is based on the identification of a hot cardboard box. Both methods were validated in a laboratory environment and outdoors. It is shown that the developed system is capable of locating a thermal object with an accuracy of up to 9 cm in a 45 m map size with a voxelization of 14 cm
Optimal Bayesian sequential sampling rules for the economic evaluation of health technologies
No full textWe present a Bayes sequential economic evaluation model for health technologies in which an investigator has flexibility over the timing of a decision to stop carrying out research and to conclude that one technology is preferred to another on cost-effectiveness grounds. We implement the model by using an evaluation of the treatment of bacterial sinusitis and derive approximations of the optimal stopping rule as a function of accumulated sample size. We compare the performance of the model with existing frequentist and Bayes sequential designs and investigate the sensitivity of the stopping rule to changes in the parameters of the model. Our results suggest that accounting for the dynamic nature of experimentation, together with its economic parameters, should lead to greater efficiency in resource allocation within healthcare systems
Optimal sequential sampling rules for the economic evaluation of health technologies
No full textReferring to the literature on optimal stopping under sequential sampling developed by Chernoff and collaborators, we solve a dynamic model of the economic evaluation of a new health technology, deriving optimal rules for technology adoption, research abandonment and continuation as functions of sample size. The model extends the existing literature to the case where an adoption decision can be deferred and involves a degree of irreversibility. We explore the model's applicability in a case study of the economic evaluation of Drug Eluting Stents (DES), deriving dynamic adoption and abandonment thresholds which are a function of the model's economic parameters. A key result is that referring to a single cost-effectiveness threshold may be sub-optima
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