Uncertainties regarding dengue modeling in Rio de Janeiro, Brazil

Dengue fever is currently the most important arthropod-borne viral disease in Brazil. Mathematical modeling of disease dynamics is a very useful tool for the evaluation of control measures. To be used in decision-making, however, a mathematical model must be carefully parameterized and validated with epidemiological and entomological data. In this work, we developed a simple dengue model to answer three questions: (i) which parameters are worth pursuing in the field in order to develop a dengue transmission model for Brazilian cities; (ii) how vector density spatial heterogeneity influences control efforts; (iii) with a degree of uncertainty, what is the invasion potential of dengue virus type 4 (DEN-4) in Rio de Janeiro city. Our model consists of an expression for the basic reproductive number (R0) that incorporates vector density spatial heterogeneity. To deal with the uncertainty regarding parameter values, we parameterized the model using a priori probability density functions covering a range of plausible values for each parameter. Using the Latin Hypercube Sampling procedure, values for the parameters were generated. We conclude that, even in the presence of vector spatial heterogeneity, the two most important entomological parameters to be estimated in the field are the mortality rate and the extrinsic incubation period. The spatial heterogeneity of the vector population increases the risk of epidemics and makes the control strategies more complex. At last, we conclude that Rio de Janeiro is at risk of a DEN-4 invasion. Finally, we stress the point that epidemiologists, mathematicians, and entomologists need to interact more to find better approaches to the measuring and interpretation of the transmission dynamics of arthropod-borne diseases.

Aumento da eficiência dos métodos següenciais de simulação condicional

O algoritmo de simulação seqüencial estocástica mais amplamente utilizado é o de simulação seqüencial Gaussiana (ssG). Teoricamente, os métodos estocásticos reproduzem tão bem o espaço de incerteza da VA Z(u) quanto maior for o número L de realizações executadas. Entretanto, às vezes, L precisa ser tão alto que o uso dessa técnica pode se tornar proibitivo. Essa Tese apresenta uma estratégia mais eficiente a ser adotada. O algoritmo de simulação seqüencial Gaussiana foi alterado para se obter um aumento em sua eficiência. A substituição do método de Monte Carlo pela técnica de Latin Hypercube Sampling (LHS), fez com que a caracterização do espaço de incerteza da VA Z(u), para uma dada precisão, fosse alcançado mais rapidamente. A técnica proposta também garante que todo o modelo de incerteza teórico seja amostrado, sobretudo em seus trechos extremos.

Digital soil mapping: evaluation of sampling systems for soil surveys and refinement of soil maps at lower cost using legacy data

In soil surveys, several sampling systems can be used to define the most representative sites for sample collection and description of soil profiles. In recent years, the conditioned Latin hypercube sampling system has gained prominence for soil surveys. In Brazil, most of the soil maps are at small scales and in paper format, which hinders their refinement. The objectives of this work include: (i) to compare two sampling systems by conditioned Latin hypercube to map soil classes and soil properties; (II) to retrieve information from a detailed scale soil map of a pilot watershed for its refinement, comparing two data mining tools, and validation of the new soil map; and (III) to create and validate a soil map of a much larger and similar area from the extrapolation of information extracted from the existing soil map. Two sampling systems were created by conditioned Latin hypercube and by the cost-constrained conditioned Latin hypercube. At each prospection place, soil classification and measurement of the A horizon thickness were performed. Maps were generated and validated for each sampling system, comparing the efficiency of these methods. The conditioned Latin hypercube captured greater variability of soils and properties than the cost-constrained conditioned Latin hypercube, despite the former provided greater difficulty in field work. The conditioned Latin hypercube can capture greater soil variability and the cost-constrained conditioned Latin hypercube presents great potential for use in soil surveys, especially in areas of difficult access. From an existing detailed scale soil map of a pilot watershed, topographical information for each soil class was extracted from a Digital Elevation Model and its derivatives, by two data mining tools. Maps were generated using each tool. The more accurate of these tools was used for extrapolation of soil information for a much larger and similar area and the generated map was validated. It was possible to retrieve the existing soil map information and apply it on a larger area containing similar soil forming factors, at much low financial cost. The KnowledgeMiner tool for data mining, and ArcSIE, used to create the soil map, presented better results and enabled the use of existing soil map to extract soil information and its application in similar larger areas at reduced costs, which is especially important in development countries with limited financial resources for such activities, such as Brazil.

Modelagem matemática aplicada a precificação de opções

The mathematical models are critical to determine theoretical prices of options and analyze whether they are overrated or underrated. This information strongly influence in operations carried out by the investor. Therefore, it is necessary that the employee model present high degree of reliability and be consistent with the reality of investment to which it is intended. In this sense, this dissertation aims to apply the steps of mathematical modeling in the Pricing of options for decision making in the investment of a hydroelectric power plant. Was used a Monte Carlo simulation, with the Latin Hypercube Method, to determine the volatility of returns of the project. In order to validate the proposed model, compared to the results found by the Binomial Model, which is one of the models most used in this type of investment. The results reinforce the hypothesis that the mathematical modeling with the Binomial Model is critical to investment decision-making in hydroelectric power

Planejamento de reativos em sistemas elétricos de potência multi-área através de modelos estocásticos

Pós-graduação em Engenharia Elétrica - FEIS

Fossil vs. non-fossil sources of fine carbonaceous aerosols in four Chinese cities during the extreme winter haze episode of 2013

During winter 2013, extremely high concentrations (i.e., 4–20 times higher than the World Health Organization guideline) of PM2.5 (particulate matter with an aerodynamic diameter < 2.5 μm) mass concentrations (24 h samples) were found in four major cities in China including Xi'an, Beijing, Shanghai and Guangzhou. Statistical analysis of a combined data set from elemental carbon (EC), organic carbon (OC), 14C and biomass-burning marker measurements using Latin hypercube sampling allowed a quantitative source apportionment of carbonaceous aerosols. Based on 14C measurements of EC fractions (six samples each city), we found that fossil emissions from coal combustion and vehicle exhaust dominated EC with a mean contribution of 75 ± 8% across all sites. The remaining 25 ± 8% was exclusively attributed to biomass combustion, consistent with the measurements of biomass-burning markers such as anhydrosugars (levoglucosan and mannosan) and water-soluble potassium (K+). With a combination of the levoglucosan-to-mannosan and levoglucosan-to-K+ ratios, the major source of biomass burning in winter in China is suggested to be combustion of crop residues. The contribution of fossil sources to OC was highest in Beijing (58 ± 5%) and decreased from Shanghai (49 ± 2%) to Xi'an (38 ± 3%) and Guangzhou (35 ± 7%). Generally, a larger fraction of fossil OC was from secondary origins than primary sources for all sites. Non-fossil sources accounted on average for 55 ± 10 and 48 ± 9% of OC and total carbon (TC), respectively, which suggests that non-fossil emissions were very important contributors of urban carbonaceous aerosols in China. The primary biomass-burning emissions accounted for 40 ± 8, 48 ± 18, 53 ± 4 and 65 ± 26% of non-fossil OC for Xi'an, Beijing, Shanghai and Guangzhou, respectively. Other non-fossil sources excluding primary biomass burning were mainly attributed to formation of secondary organic carbon (SOC) from non-fossil precursors such as biomass-burning emissions. For each site, we also compared samples from moderately to heavily polluted days according to particulate matter mass. Despite a significant increase of the absolute mass concentrations of primary emissions from both fossil and non-fossil sources during the heavily polluted events, their relative contribution to TC was even decreased, whereas the portion of SOC was consistently increased at all sites. This observation indicates that SOC was an important fraction in the increment of carbonaceous aerosols during the haze episode in China.

Economic analysis of drought risks: an application to irrigated agriculture in Spain

Abstract This paper describes a two-part methodology for managing the risk posed by water supply variability to irrigated agriculture. First, an econometric model is used to explain the variation in the production value of irrigated agriculture. The explanatory variables include an index of irrigation water availability (surface storage levels), a price index representative of the crops grown in each geographical unit, and a time variable. The model corrects for autocorrelation and it is applied to 16 representative Spanish provinces in terms of irrigated agriculture. In the second part, the fitted models are used for the economic evaluation of drought risk. In flow variability in the hydrological system servicing each province is used to perform ex-ante evaluations of economic output for the upcoming irrigation season. The model?s error and the probability distribution functions (PDFs) of the reservoirs? storage variations are used to generate Monte Carlo (Latin Hypercube) simulations of agricultural output 7 and 3 months prior to the irrigation season. The results of these simulations illustrate the different risk profiles of each management unit, which depend on farm productivity and on the probability distribution function of water in flow to reservoirs. The potential for ex-ante drought impact assessments is demonstrated. By complementing hydrological models, this method can assist water managers and decisionmakers in managing reservoirs.

Uncertain natural frequency analysis of composite plates including effect of noise – A polynomial neural network approach

Acknowledgement SN and SS gratefully acknowledge the financial support from Lloyd’s Register Foundation Centre during this work.

Effect of Geometric Uncertainties on the Aerodynamic Characteristic of Offshore Wind Turbine Blades

Offshore wind turbines operate in a complex unsteady flow environment which causes unsteady aerodynamic loads. The unsteady flow environment is characterized by a high degree of uncertainty. In addition, geometry variations and material imperfections also cause uncertainties in the design process. Probabilistic design methods consider these uncertainties in order to reach acceptable reliability and safety levels for offshore wind turbines. Variations of the rotor blade geometry influence the aerodynamic loads which also affect the reliability of other wind turbine components. Therefore, the present paper is dealing with geometric uncertainties of the rotor blades. These can arise from manufacturing tolerances and operational wear of the blades. First, the effect of geometry variations of wind turbine airfoils on the lift and drag coefficients are investigated using a Latin hypercube sampling. Then, the resulting effects on the performance and the blade loads of an offshore wind turbine are analyzed. The variations of the airfoil geometry lead to a significant scatter of the lift and drag coefficients which also affects the damage-equivalent flapwise bending moments. In contrast to that, the effects on the power and the annual energy production are almost negligible with regard to the assumptions made.

Mucopolysaccharidosis Type Ii: Identification Of 30 Novel Mutations Among Latin American Patients.

In this study, 103 unrelated South-American patients with mucopolysaccharidosis type II (MPS II) were investigated aiming at the identification of iduronate-2-sulfatase (IDS) disease causing mutations and the possibility of some insights on the genotype-phenotype correlation The strategy used for genotyping involved the identification of the previously reported inversion/disruption of the IDS gene by PCR and screening for other mutations by PCR/SSCP. The exons with altered mobility on SSCP were sequenced, as well as all the exons of patients with no SSCP alteration. By using this strategy, we were able to find the pathogenic mutation in all patients. Alterations such as inversion/disruption and partial/total deletions of the IDS gene were found in 20/103 (19%) patients. Small insertions/deletions/indels (<22 bp) and point mutations were identified in 83/103 (88%) patients, including 30 novel mutations; except for a higher frequency of small duplications in relation to small deletions, the frequencies of major and minor alterations found in our sample are in accordance with those described in the literature.

Musculoskeletal Evaluation In Severe Haemophilia A Patients From Latin America.

There is a paucity of literature on haemophilia treatment in Latin American countries, a region characterized by rapidly improving systems of care, but with substantial disparities in treatment between countries. The aim of this study was to evaluate the musculoskeletal status of haemophilia patients from Latin America and to examine the relationship between musculoskeletal status and treatment practices across countries. The Committee of Latin America on the Therapeutics of Inhibitor Groups conducted a survey of its member country representatives on key aspects of haemophilia treatment in 10 countries. Musculoskeletal status of patients was obtained during routine comprehensive evaluations between March 2009 and March 2011. Eligible patients had severe haemophilia A (factor VIII <1%) without inhibitors (<0.6 BU mL(-1) ) and were ≥5 years of age. Musculoskeletal status was compared between three groups of countries, based primarily on differences in the availability of long-term prophylaxis. Overall, 143 patients (5-66 years of age) were enrolled from nine countries. In countries where long-term prophylaxis had been available for at least 10 years (Group A), patients aged 5-10 years had significantly better mean World Federation of Hemophilia clinical scores, fewer target joints and fewer affected joints than patients from countries where long-term prophylaxis has been available for about 5 years (Group B) or was not available (Group C). In Latin America, the musculoskeletal status of patients with severe haemophilia without inhibitors has improved significantly in association with the provision of long-term prophylaxis. As more countries in Latin America institute this practice, further improvements are anticipated.

Is Misión Milagro an effective program to prevent blindness in Latin America?

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Rates of antimicrobial resistance in latin america (2004-2007) and in vitro activity of the glycylcycline tigecycline and of other antibiotics

As a part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.), Gram-positive and Gram-negative bacterial isolates were collected from 33 centers in Latin America (centers in Argentina, Brazil, Chile, Colombia, Guatemala, Honduras, Jamaica, Mexico, Panama, Puerto Rico, and Venezuela) from January 2004 to September 2007. Argentina and Mexico were the greatest contributors of isolates to this study. Susceptibilities were determined according to Clinical Laboratory Standards Institute guidelines. Resistance levels were high for most key organisms across Latin America: 48.3% of Staphylococcus aureus isolates were methicillin-resistant while 21.4% of Acinetobacter spp. isolates were imipenem-resistant. Extended-spectrum β-lactamase were reported in 36.7% of Klebsiella pneumoniae and 20.8% of E. coli isolates. Tigecycline was the most active agent against Gram-positive isolates. Tigecycline was also highly active against all Gram-negative organisms, with the exception of Pseuodomonas aeruginosa, against which piperacillin-tazobactam was the most active agent tested (79.3% of isolates susceptible). The in vitro activity of tigecycline against both Gram-positive and Gram-negative isolates indicates that it may be an useful tool for the treatment of nosocomial infections, even those caused by organisms that are resistant to other antibacterial agents.

Clinical outcomes of long-acting injectable risperidone in patients with schizophrenia: six-month follow-up from the Electronic Schizophrenia Treatment Adherence Registry in Latin America

Background: Risperidone long-acting injection (RLAI) has been shown to be efficacious, improve compliance, and increase long-term retention rate on therapy. The aim of this work was to determine the effect of RLAI on clinical outcome and hospitalization rate in patients with schizophrenia or schizoaffective disorder enrolled in the electronic Schizophrenia Treatment Adherence Registry in Latin America. Methods: Data were collected at baseline, retrospectively for the 12 months prior to baseline, and prospectively every three months for 24 months. Hospitalization prior to therapy was assessed by a retrospective chart review. Efficacy and functioning were evaluated using Clinical Global Impression of Illness Severity (CGI-S), Personal and Social Performance (PSP), and Global Assessment of Functioning (GAF) scores. Relapse and treatment were also registered. Results: Patients were recruited in Mexico (n = 53), Brazil (n = 11), and Colombia (n = 15). Sixty-five percent (n = 52) were male, and mean age was 32.9 years. Patients were classified as having schizophrenia (n = 73) or schizoaffective disorder (n = 6). The mean dose of RLAI at six months was 34.1 mg (standard deviation = 10.2 mg). The percentage of hospitalized patients before treatment was 28.2% and 5.1% at six months after initiating RLAI (P < 0.001). Significant changes were registered on CGI-S, GAF, and PSP scores. Conclusions: RLAI was associated with an improvement in clinical symptoms and functioning, and a greater reduction in hospitalization.

Incidence and risk factors of aplastic anemia in Latin American countries: the LATIN case-control study

Background Associations between aplastic anemia and numerous drugs, pesticides and chemicals have been reported. However, at least 50% of the etiology of aplastic anemia remains unexplained. Design and Methods This was a case-control, multicenter, multinational study, designed to identify risk factors for agranulocytosis and aplastic anemia. The cases were patients with diagnosis of aplastic anemia confirmed through biopsy or bone marrow aspiration, selected through an active search of clinical laboratories, hematology clinics and medical records. The controls did not have either aplastic anemia or chronic diseases. A total of 224 patients with aplastic anemia were included in the study, each case was paired with four controls, according to sex, age group, and hospital where the case was first seen. Information was collected on demographic data, medical history, laboratory tests, medications, and other potential risk factors prior to diagnosis. Results The incidence of aplastic anemia was 1.6 cases per million per year. Higher rates of benzene exposure (>= 30 exposures per year) were associated with a greater risk of aplastic anemia (odds ratio, OR: 4.2; 95% confidence interval, CI: 1.82-9.82). Individuals exposed to chloramphenicol in the previous year had an adjusted OR for aplastic anemia of 8.7 (CI: 0.87-87.93) and those exposed to azithromycin had an adjusted OR of 11.02 (CI 1.14-108.02). Conclusions The incidence of aplastic anemia in Latin America countries is low. Although the research study centers had a high coverage of health services, the underreporting of cases of aplastic anemia in selected regions can be discussed. Frequent exposure to benzene-based products increases the risk for aplastic anemia. Few associations with specific drugs were found, and it is likely that some of these were due to chance alone.