Vitamin A deficiency and training to farmers: Evidence from a field experiment in Mozambique

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Assessment of hydrogen sulfide removal from biogas using a field scale anoxic biotrickling filter.

Hydrogen sulphide is one of the most toxic and corrosive compound present in swine-derived biogas streams.In this study, afield scale biotrickling filter for the removal of hydrogen sulfide was investigated.A Biofilter packed with supporting biofilm materials was fed continuously with a proprietary nutrient solution and operatedfor over 73days. The system has been operating with a H2S inlet concentrations ranging from 1,000to 3,000 ppm.Significant removal efficiencies >95% was demonstrated. pH of the stock feeding solution decreased from 6.2 to as low as 3.5within couple days.The resulting drop in pH provided circumstantial evidence to support biological H2 Soxidation to sulphuric acid by sulfide-oxidizers. Sulfur precipitation was also observed to occur. The results suggested that H2S removal from biogas stream can be efficiently achieved using portable, low cost and maintenance free biotrickling filters.

Forecasts of relative performance in tournaments: Evidence from the field

This paper uses a field experiment to investigate the quality of individuals’ forecasts of relative performance in tournaments. We ask players in luck-based (poker) and skill-based (chess) tournaments to make point forecasts of rank. The main finding of the paper is that players’ forecasts in both types of tournaments are biased towards overestimation of relative performance. However, the size of the biases found is not as large as the ones often reported in the psychology literature. We also find support for the “unskilled and unaware hypothesis” in chess: high skilled chess players make better forecasts than low skilled chess players. Finally, we find that chess players’ forecasts of relative performance are not efficient.

Trypanocide treatment among adults with chronic Chagas disease living in Santa Fe city (Argentina), over a mean follow-up of 21 years: parasitological, serological and clinical evolution

The efficacy of treatment with nifurtimox and/or benznidazole among adults with chronic Chagas disease with no previous electrocardiographic disturbances was evaluated over a mean follow-up of 21 years, by means of conventional serology, xenodiagnosis, clinical examination, electrocardiograms and chest X-ray. One hundred and eleven patients, between 17 and 46 years old, were studied: 54 underwent treatment (nifurtimox 27, benznidazole 27) and 57 remained untreated (control group). Xenodiagnosis was performed on 65% of them: 36/38 of the treated and 9/34 of the untreated patients had previous positive xenodiagnosis. Post-treatment, 133 xenodiagnoses were performed on 41 patients, all resulting negative. In the control group, 29 xenodiagnoses were performed on 14 patients; 2 resulted positive. Sera stored during the follow-up were simultaneously analyzed through conventional serology tests (IHA; DA-2ME; IIF). The serological evolution in the treated group was: a) 37% underwent negative seroconversion (nifurtimox 11, benznidazole 9); b) 27.8% decreased titers (nifurtimox 9, benznidazole 6), 9 showed inconclusive final serology (nifurtimox 7, benznidazole 2); c) 35.2% remained positive with constant titers (nifurtimox 7; benznidazole 12). The control group conserved the initial antibody levels during the follow-up. In the clinical evolution, 2/54 (3.7%) of the treated and 9/57 (15.8%) of the untreated patients showed electrocardiographic disturbances attributable to Chagas myocardiopathy, with a statistically relevant difference (p<0.05). Treatment caused deparasitation in at least 37% of the chronically infected adults and a protective effect on their clinical evolution.

Automatic delimitation of the clinical region of interest in ultra-wide field of view images of the retina

Retinal ultra-wide field of view images (fundus images) provides the visu-alization of a large part of the retina though, artifacts may appear in those images. Eyelashes and eyelids often cover the clinical region of interest and worse, eye-lashes can be mistaken with arteries and/or veins when those images are put through automatic diagnosis or segmentation software creating, in those cases, the appearance of false positives results. Correcting this problem, the first step in the development of qualified auto-matic diseases diagnosis programs can be done and in that way the development of an objective tool to assess diseases eradicating the human error from those processes can also be achieved. In this work the development of a tool that automatically delimitates the clinical region of interest is proposed by retrieving features from the images that will be analyzed by an automatic classifier. This automatic classifier will evaluate the information and will decide which part of the image is of interest and which part contains artifacts. The results were validated by implementing a software in C# language and validated through a statistical analysis. From those results it was confirmed that the methodology presented is capable of detecting artifacts and selecting the clin-ical region of interest in fundus images of the retina.

Caracterização de cepas de referência de Leptospira sp utilizando a técnica de pulsed field gel electrophoresis

INTRODUÇÃO: A leptospirose é uma zoonose endêmica, mundialmente distribuída, causada por bactérias do gênero Leptospira. Este gênero compreende espécies patogênicas e saprofíticas, com mais de 200 sorovares distintos, dificultando sua caracterização. A técnica de pulsed field gel electrophoresis tem sido empregada como uma ferramenta para auxiliar nesta caracterização. Os objetivos deste trabalho foram padronizar a técnica de PFGE, determinar os perfis moleculares das cepas de referência utilizadas pelo Laboratório de Referência Nacional para Leptospirose/Centro Colaborador da Organização Mundial de Saúde para Leptospirose e criar um banco de dados com estes perfis. MÉTODOS: Foram analisadas, por PFGE, dezenove cepas utilizando a enzima de restrição NotI. RESULTADOS: Cada cepa apresentou um perfil único que pode ser considerado como uma identidade genômica específica, com exceção dos sorovares Icterohaemorrhagiae e Copenhageni, cujos perfis foram indistinguíveis. CONCLUSÕES: Dessa forma, foi possível a criação de um banco de perfis moleculares que está sendo utilizado no Laboratório para a comparação e identificação de cepas isoladas de quadros clínicos.

Numerical prediction of diffusion and electric field-induced iron nanoparticle transport

Zero valent iron nanoparticles (nZVI) are considered very promising for the remediation of contaminated soils and groundwaters. However, an important issue related to their limited mobility remains unsolved. Direct current can be used to enhance the nanoparticles transport, based on the same principles of electrokinetic remediation. In this work, a generalized physicochemical model was developed and solved numerically to describe the nZVI transport through porous media under electric field, and with different electrolytes (with different ionic strengths). The model consists of the Nernst–Planck coupled system of equations, which accounts for the mass balance of ionic species in a fluid medium, when both the diffusion and electromigration of the ions are considered. The diffusion and electrophoretic transport of the negatively charged nZVI particles were also considered in the system. The contribution of electroosmotic flow to the overall mass transport was included in the model for all cases. The nZVI effective mobility values in the porous medium are very low (10−7–10−4 cm2 V−1 s−1), due to the counterbalance between the positive electroosmotic flow and the electrophoretic transport of the negatively charged nanoparticles. The higher the nZVI concentration is in the matrix, the higher the aggregation; therefore, low concentration of nZVI suspensions must be used for successful field application.

Insurance segmentation as unfair discrimination: what to expect next in the wake of Test-Achats

Proceedings of the 16th Annual Conference organized by the Insurance Law Association of Serbia and German Foundation for International Legal Co-Operation (IRZ), entitled "Insurance law, governance and transparency: basics of the legal certainty" Palic Serbia, 17-19 April 2015.

Occurrence of Triatoma costalimai (Hemiptera: Reduviidae) in different environments and climatic seasons: a field study in the Brazilian savanna

INTRODUCTION: Trypanosoma cruzi-infected specimens of Triatoma costalimai have been detected in domiciliary units of Central Brazil, thereby maintaining the potential risk of vectorial transmission of Chagas disease. The aim of this study was to determine the occurrence and natural infection of T. costalimai in different environments (gallery forest, dry forest and peridomicile) and climatic seasons (wet and dry), in the municipality of Mambaí, State of Goiás, Brazil. METHODS: Triatomines were captured in October 2010 and in June 2011, employing two different methods (manual capture and mouse-baited adhesive traps). The insects were later separated by sex and nymphal stage, counted and examined parasitologically by abdominal compression and microscopic analysis of feces. RESULTS: Triatoma costalimai was found in three environments and in the two seasons studied. Overall, capture success of 900 traps and 60 blocks of rocks inspected was 5.8% and 11.7%, respectively. The occurrence of T. costalimai was higher among rocks in the peridomicile, where 97% of the 131 specimens were captured. The proportion of nymphs (98%) was much higher than that of adults, which were only detected in peridomicile. Most (95%) insects were captured during the wet season, with predominance of early-stage nymphs. None of the 43 specimens examined were infected by trypanosomatids. CONCLUSIONS: The results indicate a greater occurrence of T. costalimai in peridomiciliary environments and during the wet season in Mambaí, Goiás, highlighting the synanthropic behavior of this triatomine species in one area of the Brazilian savanna and the importance of entomological surveillance.

Impact of insecticide resistance on the field control of Aedes aegypti in the State of São Paulo

IntroductionThe need to control dengue transmission by means of insecticides has led to the development of resistance to most of the products used worldwide against mosquitoes. In the State of São Paulo, the Superintendência de Controle de Endemias(SUCEN) has annually monitored the susceptibility of Aedes aegypti to insecticides since 1996; since 1999, surveys were conducted in collaboration with the National Network of Laboratories (MoReNAa Network) and were coordinated by the Ministry of Health. In this study, in addition to the biological characterization of insecticide resistance in the laboratory, the impact of resistance on field control was evaluated for vector populations that showed resistance in laboratory assays.MethodsField efficacy tests with larvicides and adulticides were performed over a 13-year period, using World Health Organization protocols.ResultsData from the field tests showed a reduction in the residual effect of temephos on populations with a resistance ratio of 3. For adults, field control was less effective in populations characterized as resistant in laboratory qualitative assays, and this was confirmed using qualitative assays and field evaluation.ConclusionsOur results indicated that management of resistance development needs to be adopted when insect populations show reduced susceptibility. The use of insecticides is a self-limiting tool that needs to be applied cautiously, and dengue control requires more sustainable strategies.

Detection of intestinal parasites on field-grown strawberries in the Federal District of Brazil

Introduction This study evaluated the presence of pathogenic human parasites on field-grown strawberries in the Federal District of Brazil. Methods A total of 48 samples of strawberries and 48 soil samples from 16 properties were analyzed. Results Contaminated strawberries were detected in 56% of the properties. Schistosoma mansoni, Ascaris lumbricoides or Ascaris suum, Balantidium coli, Endolimax nana, and Entamoeba spp. were detected. Soil was contaminated with Entamoeba spp., Entamoeba coli, Strongyloides spp., Ancylostomatidae, and Hymenolepis nana. Conclusions Producers should be instructed on the safe handling of strawberries in order to reduce the incidence of strawberries that are contaminated with enteroparasites.

Susceptibility of Triatoma sordida Stal, 1859 (Hemiptera: Reduviidae) to alpha-cypermethrin under natural climatic conditions

Abstract:INTRODUCTION:Despite the recommendations by interpretation of resistance ratios obtained in laboratory bioassays, little is known about the actual impact of these results in the effectiveness of vector control activities in the field. In this context, our objective was to determine the mean value of different resistance ratios obtained by laboratory bioassays performed as part of the chemical control strategies of Triatoma sordida in the field.METHODS:Field bioassays were developed in Monte Azul and Coração de Jesus (Southeast, Brazil). In each location, samples were formed with three domestic units treated with alpha-cypermethrin 20.0% (Alfatek (r) 200 SC). One day after spraying, 10 fifth-instar nymphs remained in contact with the surfaces treated (adobe with plaster, adobe without plaster, or wood) with insecticide in plastic cones for 72h. Three cones were exposed inside the intradomicile and the peridomicile. The insects in the control group were exposed to an insecticide-free piece of cardboard. Mortality was measured 72h after removal of the insects from the treated surfaces. The tests were realized in triplicate.RESULTS:Mortality was 100.0% in all locations, except for Monte Azul; Landinho (96.6%) and Coração de Jesus; Barriguda (96.6%).CONCLUSIONS:Although the resistant populations in laboratory tests proved to be susceptible in the field, this observation is not sufficient to suggest that the cut-off points used to justify the resistance ratio should be changed. In this sense, we recommend that laboratory and field bioassays are carried out with a greater number of Triatominae populations to allow more in-depth consideration of the subject.

Aedes aegypti eggs oviposited on water surface collected from field ovitraps in Nova Iguaçu City, Brazil

ABSTRACT INTRODUCTION: Aedes aegypti eggs can be collected from the water surface. METHODS: Aedes aegypti oviposition from 97 field ovitraps was studied. RESULTS: Of the 16,016 eggs collected, 11,439 were obtained from paddles in ovitraps and 4,577 from water. Further, 89 (91.8%) traps contained eggs on water and 22 (22.7%) traps contained eggs only on water. CONCLUSIONS: In field traps, Aedes aegypti females usually oviposit some eggs on water surface suggesting that they might also oviposit on water of some natural breeding, and this possibility needs to be investigated. Eggs oviposited on water need to be considered for collecting trap data.

Field-effect transistors based on Zinc oxide nanoparticles

This work reports the development of field-effect transistors (FETs), whose channel is based on zinc oxide (ZnO) nanoparticles (NPs). Using screen-printing as the primary deposition technique, different inks were developed, where the semiconducting ink is based on a ZnO NPs dispersion in ethyl cellulose (EC). These inks were used to print electrolyte-gated transistors (EGTs) in a staggered-top gate structure on glass substrates, using a lithium-based polymeric electrolyte. In another approach, FETs with a staggered-bottom gate structure on paper were developed using a sol-gel method to functionalize the paper’s surface with ZnO NPs, using zinc acetate dihydrate (ZnC4H6O4·2H2O) and sodium hydroxide (NaOH) as precursors. In this case, the paper itself was used as dielectric. The various layers of the two devices were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric and differential scanning calorimetric analyses (TG-DSC). Electrochemical impedance spectroscopy (EIS) was used in order to evaluate the electric double-layer (EDL) formation, in the case of the EGTs. The ZnO NPs EGTs present electrical modulation for annealing temperatures equal or superior to 300 ºC and in terms of electrical properties they showed On/Off ratios in the order of 103, saturation mobilities (μSat) of 1.49x10-1 cm2(Vs)-1 and transconductance (gm) of 10-5 S. On the other hand, the ZnO NPs FETs on paper exhibited On/Off ratios in the order of 102, μSat of 4.83x10- 3 cm2(Vs)-1and gm around 10-8 S.