Central-West Region Of Brazil Research Articles

Clinical overview and prevalence of acute renal disorders: retrospective cohort

Objective: To evaluate the evolutionary panorama and prevalence of acute kidney disorders in the intensive care setting. Method: This is a retrospective cohort study conducted with 74 patients admitted to an intensive care unit (ICU) in the central-west region of Brazil. Results: Of the 74 patients, the majority (47.3%) had severe AKI (KDIGO 2 and 3), and 25.7% were classified as KDIGO 1 (less severe); 6 patients (8.1%) developed acute kidney disease (AKD). Factors such as age (p = 0.02); use of vasoactive drugs (VAD) (p = 0.001), specifically norepinephrine (p < 0.001), among others, were associated with the occurrence of more severe AKI. Conclusion: A high prevalence of acute kidney disorders was identified in the ICU, particularly AKI compared to AKD.

NO-cGMP-K+ Channels Pathways Participate in the Antihypertensive Effects of Attalea phalerata Martius ex Spreng Oil-Loaded Nanocapsules.

Attalea phalerata Martius ex Spreng is a palm tree that is widely distributed in the Central-West region of Brazil. In this study, we investigated whether the oil-loaded nanocapsules of A. phalerata (APON) have acute and long-lasting antihypertensive effects in male spontaneously hypertensive rats (SHR), as well as explored the underlying molecular mechanisms. APON was prepared using the interfacial polymer deposition method. The particle size, polydispersity index, and zeta potential were investigated using dynamic and electrophoretic light scattering. The antihypertensive effects of APON (administered at doses of 1, 3, and 10 mg/kg) were evaluated after acute intraduodenal administration and after 7 days of oral treatment. To investigate the molecular pathways involved, we used pharmacological antagonists and inhibitors that target prostaglandin/cyclic adenosine monophosphate, nitric oxide/cyclic guanosine monophosphate, and potassium channels. Both acute and prolonged administration of APON (at doses of 3 and 10 mg/kg) resulted in a significant reduction in systolic, diastolic, and mean arterial pressure. Prior treatment with a non-selective nitric oxide synthase inhibitor (Nω-nitro-L-arginine methyl ester), guanylyl cyclase inhibitor (methylene blue), or non-selective calcium-sensitive K+ channel blocker (tetraethylammonium) abolished the antihypertensive effects of APON. Our study showed that A. phalerata oil-loaded nanocapsules have a significant antihypertensive effect in SHR after both short-term and long-term (7-day) use. This effect seems to rely on the vascular endothelium function and involves the NO-cGMP-K+ channel pathway. This research suggests a new direction for future studies to definitively prove the therapeutic benefits of APON in treating cardiovascular disease.

Public environmental actions and urban land use planning in the Central-west Region of Brazil

The purpose of this study was to assess the dissemination of information on environmental actions carried out by public agents in municipalities in the Central-West region of Brazil. A Municipal Index of Public Environmental Actions (IMAPA) was created for this purpose, and the municipalities with the best results in terms of including ecosystem services in their planning were verified. Data from the 2017 Municipal Basic Information Survey provided by the Brazilian Institute of Geography and Statistics were also used. Statistical analyses were conducted using factorial and cluster analyses. The municipalities with the best results in terms of public environmental policies were identified, and their respective master plans were analyzed on their institutional websites (the master plan in Brazil is the instrument used to organize the development and urban expansion of municipalities). Furthermore, elements related to ecosystem services were identified using a script to collect information and analyze the content. According to the IMAPA findings, 20 municipalities in the Central-West region have the best indicators or information dissemination in the region for: 1) Environmental legislation on land use, 2) Local payment for environmental services, and 3) Specific environmental legislation to basic sanitation. Based on the script used, content analysis revealed that there are elements inserted in the master plans regarding ecosystem services, with the potential to expand this content in the documents.

Identificação de isolados de leveduras do gênero Trichosporon de infecções superficiais em pacientes do sexo masculino do Brasil Central: uma abordagem sobre a diversidade de infecções causadas por esse fungo basidiomiceto

Abstract The genus Trichosporon are currently recognized as opportunistic pathogens capable of causing superficial "white piedra" infections and potentially fatal invasive diseases (Trichosporonosis). In this work, determine the agent Trichosporon spp. isolated from the skin and appendages of a male population group in the Central-West region of Brazil. The isolates were analyzed by phenotypic, biochemical and molecular methods. Twenty-five strains of Trichosporon were isolated: T. asahii (18; 72%), followed by T. inkin (4; 16%) and T. faecale (3; 12%). Skin infections were the most affected (16; 64%) and the genitocrural region (13; 52%) was the most affected. The highest rate of isolation occurred between the ages of 21 and 30 years (9; 36%), with black men (African descent) (13; 52%) being the most affected by this type of superficial infection. After the advent of molecular techniques, more than 50 subspecies and about 16 different strains have been reported to cause human disease. In this series, three species of the genus Trichosporon of medical importance were highlighted, colonizing the genital and perigenital region of the studied population. For the identifications, classical phenotypic methods associated with genotypic identification were carried out, using molecular techniques based on the study of DNA; using sequence analysis of the DNA intergenic spacer region 1 (IGS1).

Evaluation of the relative efficiency of broiler housing facilities using Data Envelopment Analysis

This research aimed to observe the efficiency of productive units of broiler chickens using Data Envelopment Analysis (DEA) with the CCR model. This technique aims to define an efficiency frontier from the process’s inputs and outputs, which can be used to evaluate the relative efficiency of the studied units and to define consistent goals to the units bellow the expected performance, comparing units of the same technology profile and scale. The study identified benchmark units as performance reference in order the improve the organization’s results level, increasing productivity and reducing costs. Twenty-five production units were examined in aviaries with automated technology, located in the Center-West region of Brazil, of which 23 presented global inefficiency, with potential to increase the volume of meat produced with the same amount of inputs. The units that contained only male birds presented the highest global efficiencies, followed by the mixed units and, at last, the units that contained only female birds. The units with the lowest efficiency rates were the ones with the highest mortality rates (3.3 and 4.05%). Several other factors can contribute to these results, such as, possible human errors ant the equipment’s adjustments and the employment of correct husbandry techniques. Investigating the low performance causes is necessary for the company to design a strategy of performance improvement.

Climate zoning: identifying suitable regions for the occurrence of Alternaria Brown spot in tangerine trees in Brazil.

Brazilian citrus farming has been migrating to nontraditional citrus-growing regions, which can be considered a challenge for citrus growers, as not all these areas are suitable for tangerine cultivation. Thus, the mapping of regions exhibiting favorable climatic conditions for Alternaria brown spot has become crucial in the selection of appropriate locations for the establishment of new orchards. This mapping enables the implementation of an avoidance strategy, which entails steering clear of areas where the disease is prevalent, aligning with fundamental principles of disease control. Thus, this study seeks to zone areas with high and low climatic favorability for the occurrence of Alternaria brown spot in tangerine trees in Brazil. Historical climate data series from the NASA-POWER database were used for all municipalities in Brazil. Agrometeorological variables used to determine the development of Alternaria brown spot were average monthly air temperature (Tmean) and duration of leaf wetness period (LWD). Areas were considered unsuitable climatically when Tmean was <17 °C or >33 °C, relatively suitable when Tmean was between 13 °C and 33 °C and LWD <10%, and climatically suitable when Tmean was between 13 °C and 33 °C and LWD >10%. The states of Paraná, Santa Catarina and Rio Grande do Sul showed greater thermal amplitude within months and throughout the year. The southern region of the country has harsher winters, with minimum temperatures below 15 °C, which is unfavorable for the disease incidence. The states with the greatest favorability for Alternaria brown spot were Paraná, Santa Catarina, and Rio Grande do Sul, mainly from May to September. Rio Grande do Sul was the state in this region that showed the greatest favorability, as a consequence of leaf wetness exceeding 10 h. The main tangerine-producing regions in Brazil, including the southern part of Minas Gerais, the state of São Paulo and the metropolitan region of Porto Alegre, were mostly classified as relatively favorable areas for the occurrence of Alternaria brown spot. It is recommended that when establishing new tangerine orchards, regions with lower favorability for the occurrence of Alternaria brown spot, such as the North and Central-West regions of Brazil, particularly the states of Amazonas, Pará and Mato Grosso, should be selected. © 2023 Society of Chemical Industry.

Clinical-epidemiological aspects and prognostic factors associated with death from visceral leishmaniasis between the years 2010 to 2019 in the Central-West region of Brazil

In Brazil, the fatality rate for visceral leishmaniasis is high, and it is important to investigate its associated factors. The aim of this study was to analyze the clinical-epidemiological profile and prognostic factors associated with death from visceral leishmaniasis (VL) in the Central-West region of Brazil, between 2010 and 2019. A study of series of VL cases was carried out using data obtained from the Sistema Nacional de Agravos de Notificação (SINAN). Multivariate logistic regression was performed to identify variables associated with deaths. Male (64.96%); age group ≤5 years (28.51%); mixed race/color (59.20%); and level of education incomplete primary education (45.16%) were the most affected. The most frequent symptoms were fever (87.65%), weakness (77.56%), enlarged spleen (70.22%) and liver (67.33%), weight loss (67.22%) and pallor (63.41%). Co-infection with HIV was observed in 15.84% of patients. The parasitological diagnosis was positive in 74.17% and the Indirect Immunofluorescence (IIF) in 82.80%. The drug most used for treatment was pentavalent antimony (41.96%). Regarding the evolution of VL, cure was recorded for 82.90% of patients and death from VL in 8.30%. Factors associated with death from VL were: age group ≥20 and < 60 (OR 2.95; 95% CI 1.98–4.38) and ≥ 60 (OR 5.84; 95% CI 3.63–9.38), edema (OR 2.27; 95% CI 1.64–3.13), pallor (OR 1.53; 95% CI 1.06–2.20), infectious condition (OR 1.56; 95% CI 1.12–2.15) and hemorrhagic phenomena (OR 2.87; 95% CI 2.02–4.08). New studies are needed in order to better manage VL control, monitoring, prevention and primary care strategies.

First record of Siluriformes from the northernmost portion of the Bauru Group (Upper Cretaceous) in the Center-West region of Brazil

This work presents the first record of bony fish from the Maastrichtian of the Marília Formation (Bauru Group) in Goiás State, Brazil. A fragment of a pectoral spine, recovered by screen-washing, clearly represents an important catfish (Siluriformes) record from the Late Cretaceous of South America. The material possesses similarities with forms from the Campanian - early-Maastrichtian of the Adamantina Formation and the Maastrichtian of the Marília (São Paulo State) and El Molino (Bolivia) formations. Inclusion of the new material from Goiás in the dataset for the aforementioned areas within a paleoenvironmental setting provides evidence that Late Cretaceous catfish had a wider distribution than previously known.

Behavioral and Morphological Traits of Nellore Cattle That Can Influence Calf Survival and Performance from Birth to Weaning

This study aimed to identify behavioral and morphological traits of Nellore cattle that can influence calves’ survival and pre-weaning performance. It was performed in two units of a large-scale cow–calf operation farm located in the Central-West region of Brazil, with 975 cow–calf dyads, by scoring cows’ maternal protective behavior, body condition, horns, udder suspension (US), teat size (TS) and calves’ vigor. TS was used to determine teat symmetry (TSm). The production unit where calves were born, their birth date, sex, and birth (BW) and weaning weights were also recorded. Cow ages at calving and production units were used to categorize the cows into twelve classes (Cage). The Shapiro–Wilk test alongside tables of frequencies were used to determine if continuous and categorical variables followed a normal distribution, respectively. Two datasets were considered in statistical analyses: (i) 975 dyad records were used to identify potential factors influencing calf survivability and (ii) 936 records of weaned calves were used to assess pre-weaning performance. Generalized linear models were used to assess the effect of target traits on the calves’ weight adjusted for 210 days of age (W210, kg) and pre-weaning average daily gain (preADG, kg/day). Tukey’s test was used to compare W210 and preADG means. Pearson’s correlation coefficients were estimated between BW, W210 and preADG. Cage, US and the TSm significantly affected pre-weaning calf performance (p &lt; 0.01). Older cows (independently of the production unit) and those with intermediate US and symmetrical teats weaned heavier calves. As expected, positive and significant correlation was observed between BW and preADG (r = 0.35), which, in turn, was highly correlated with W210 (r = 0.99). We concluded that none of the behavioral and morphological traits influenced calf survivability, but cow age, US and TSm impacted pre-weaning performance, with 8- to 11-year-old cows and those with intermediate US and symmetric teats leading to better calf performance at weaning.

Diversidade genética e fenotípica de uma população de plântulas de moringa a partir de descritores morfológicos

Moringa (Moringa oleifera Lam. - Moringaceae) is a plant originating in India, which has been widely cultivated in different regions of the world, especially due to the nutritional properties of its leaves, which are of high economic, medicinal and industrial interest. However, there are no reports on the genotypic and phenotypic diversity of moringa seedlings cultivated in the Central-West region of Brazil. This study aimed to characterize a population of moringa seedlings using different qualitative morphological descriptors. A population consisting of 1,263 28-day-old moringa plants was initially classified and separated into four distinct phenotypic groups based on hypocotyl color [seedlings with hypocotyls colored green (100% green), ¾ green (75% green and 25% purple ), ¾ purple (25% green and 75% purple), and purple hypocotyl (100% purple)]. Initially, the seedling emergence rate and the frequency of occurrence of the different hypocotyl color classes in the total population were evaluated. Subsequently, 10 morphological descriptors were evaluated in each group of plants with different hypocotyl color. The plant emergence rate was 74%, indicating the adequate physiological quality of the seeds. The separation of the population into four phenotypic groups based on the color of the hypocotyl allowed us to separate 432 plants (34.2%) with a green hypocotyl, 480 plants (38.0%) with a ¾ green color, 336 plants (26.6% ) ¾ purple in color and 15 plants (1.2%) with purple hypocotyls. The results reported that of the ten morphological descriptors evaluated, only the type of insertion of the first pair of leaves (TI_1F) and the height of insertion of the first leaf (AI_1F) have significant differences (P &lt; 0.05) between the different phenotypic groups of seedlings. moringa. Seedlings from the phenotypic group with purple or ¾ purple hypocotyls have the entire insertion of the first pair of daughters of the opposite type, while seedlings with green and ¾ green hypocotyls have, respectively, 25% and 42% of the plants with the insertion of the first pair of alternating leaves. Seedlings with purple hypocotyls have a higher insertion height of the first leaf (AI_1F) when compared to green and ¾ green seedlings. Highly significant and negative correlations were obtained between TI_1F and DC (–0.99, P &lt; 0.05) and VR (–0.96; P &lt; 0.05). Highly significant and positive correlations were obtained between AI_1F and DC (0.96; P &lt; 0.05). It can be stated that there is genetic and phenotypic variability within a population of moringa seedlings, and the distinct phenotypic groups separated based on hypocotyl color have some characteristics or morphological descriptors typical of their group.

Seroprevalence of Equine Leptospirosis in the State of Goiás, Brazil.

Leptospirosis, caused by Leptospira, is a zoonotic disease that, in horses, is linked to abortions, uveitis, and sporadic occurrences of liver and kidney disease, often resulting in significant economic losses for farmers. Research on the prevalence of leptospirosis in horses in the central-west region of Brazil has been relatively scarce. Thus, the present study aimed to determine the prevalence of leptospirosis in equine herds in the state of Goiás (Central Brazil). Blood samples were collected from 894 equids at 294 randomly selected farms divided into three different strata according to their herd characteristics. The microscopic agglutination test for the detection of anti-Leptospira agglutinins was carried out and the results showed that among the 294 sampled farms, 213 (72.9%; CI 95% 71.7-78.9) had one or more animals positive for leptospirosis, and of the 894 horses sampled, 513 (61.6%; CI 95% 54.3-69.0) were seropositive for leptospirosis. Djasiman, Icterohaemorrhagiae, and Australis were the most prevalent serogroups. The results showed a high prevalence of seropositive animals and a widespread distribution of positive farms in the state of Goiás. Thus, environmental sanitation measures and health education to prevent and control equine leptospirosis in the state are required.

Suicide among Indigenous peoples in Brazil from 2000 to 2020: a descriptive study

Previous studies in Australia, Canada, and Brazil, found that suicide among ethnic minority groups is higher than in the general population. Indigenous peoples in Brazil have been reported to have a high suicide rate, with reports of suicide clusters occurring in several communities. The objective of this study was to report trends in countrywide suicide rates among Indigenous peoples in Brazil between 2000 and 2020, and to compare these with the non-Indigenous population. This ecological study used Indigenous suicide data collected from all regions of Brazil during a 21-year period, between 2000 and 2020. We used suicide estimates from the Mortality Information System (SIM), available at the Brazilian Health Ministry website (DATASUS). Suicide mortality rates by state and region were calculated using the estimated Indigenous population from the 2010 census, and estimated population proportions for the other years. We performed a trend analysis and compared trends in suicide between the Indigenous and non-Indigenous population during the period studied. Suicide rates among Indigenous Brazilians have reached more than two and a half times the levels for the overall Brazilian population in 2020 (17.57 suicide deaths versus 6.35 suicide deaths per 100,000 inhabitants, respectively). The Central-West region of Brazil had the highest suicide rates among Indigenous Brazilians over the study period, reaching 58.8 deaths/100,000 inhabitants in 2008. The younger age group (10-24 years old) had the highest suicide rates for all the years studied. Time-series analyses showed a trend of statistically significant increases in suicide rates in Brazil for both the Indigenous and non-Indigenous population during the study period. The North region, and specifically Amazonas state, has shown a decisive increase in suicide rates among the Indigenous populations. The suicide rate for Indigenous people in Brazil, excluding cases in Amazonas and Mato Grosso do Sul states, were similar to those for the entire Brazilian population, showing that the Indigenous peoples who are the most vulnerable to suicide reside in these locations. While there were statistically significant increases in suicide rates for all Brazilians over the study period, they remained alarmingly high among Indigenous people, compared to their non-Indigenous counterparts. The high suicide rates among Indigenous people, and younger individuals in particular (aged between 10 and 24), reinforces the need for specific prevention strategies for these populations. Further studies should be concentrated on determining risk factors in distinct ethnic groups, specifically within regions experiencing an elevated risk, such as the states of Amazonas and Mato Grosso do Sul. Research reported in this publication was supported by the National Institute of Mental Health of the National Institutes of Health under award number R01MH128911-01. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

THE NEST OF THE SCARLET-HEADED BLACKBIRD AMBLYRAMPHUS HOLOSERICEUS IN BRAZIL WITH NOTES ON ITS BREEDING BEHAVIOR

Although it is a common marsh bird of central Brazil, there is little information about the reproductive biology of the Scarlet-headed Blackbird Amblyramphus holosericeus. Here we present data from observations made of two nests —found in November 2005 and March 2008— amid the vegetation of a flooded area in the Pantanal of Mato Grosso, the central-west region of Brazil. The nests were built by the couple attached to marshy vegetation, at least 1 m above the surface of the water. The clutches consisted of two eggs with a greenish background color, spotted with fine brown striations and some small, spaced spots across the surface. In one of the nests the incubation period lasted 13 days. Both male and female cared for the chicks, who left the nest around 10 days after hatching. Despite its Least Concern global conservation status, the species could be experiencing a population decline, primarily due to the destruction of swamp areas and to frequent fires in much of the Pantanal region during drought periods.

Climate impact on combined cycle thermoelectric power plant in hot and humid regions

Thermoelectric power plants have been designed to operate in ISO conditions, similar to the temperate climatic conditions of the northern hemisphere. Thus, some equipment used in tropical regions operated outside the ideal conditions, with high relative humidity and ambient temperature. This ends up impairing its efficiency and maximum generation. This paper presents the analysis of 2020 and 2021 hourly electric generation and climatic conditions data for 2020 from the gas based combined cycle Cuiabá Thermoelectric Power Plant, located in the state of Mato Grosso do Sul, center-west region of Brazil. The main objective is to present and discuss the correlations between meteorological conditions and power generation in the plant. Results show a strong correlation between generation and the wet bulb temperature. They also show that high wind speeds, increase thermal losses and the efficiency of the steam cycle. This paper shows that thermal electric power plants are particularly sensitive to climate conditions in hot and humid regions.

PEDAGOGIC STRATEGIES USED FOR REMOTE PHYSICAL EDUCATION CLASSES DURING THE COVID-19 PANDEMIC IN BRAZIL

The pandemic period of the new coronavirus, the COVID 19, paralyzed the whole world, just as Brazil, due to the virus proliferation and its several consequences, such as the death of those infected by the virus, there were several governmental actions to tackle the epidemic, affecting the economy with the closing of commerce and also affecting the educational sector. In this respect, it is important to remember that during this period there were adaptations in the teaching-learning process, changing the pedagogical practices. While in some Brazilian cities the classes started to be executed through digital platforms, in other places, due to the lack of access to the internet, an apostille system was used, thus causing access and permanence problems for both students and teachers in the education system. The difficulties faced by education professionals, evidenced by teachers, principals and students, and it must be said in passing that the latter were the most affected and forced to adapt to the new measures and adapt to technologies that in turn at that time was a totally unknown environment for everyone. All things considered, although all teachers have faced different difficulties, it is of utmost importance to highlight the teachers of physical education who were undoubtedly also affected and had to reinvent themselves to continue their classes and activities during the pandemic period, since this subject has a theoretical and practical organization. Given this reality, this paper aims to highlight the pedagogical practices and tools used by physical education teachers in the north, northeast, south, southeast and central-west regions of Brazil during the remote classes due to the pandemic of covid-19, for both used the qualitative approach of the bibliographic type having as methodological tool the analysis of articles as a source of research to be able to acquire the results to demonstrate during the development of the bibliographic research. Thus, it was concluded that The teachers used the media and technological tools in their favor to carry out their classes, making the effective participation as much as possible and then being able to notice the progression of their students in relation to the classes even when they were distant from the face-to-face reality that was the classroom.

Neurosyphilis in patients at a university hospital in the central west region of Brazil

Neurosyphilis in patients at a university hospital in the central west region of Brazil

Effect of Insect Growth Regulator Insecticides Novaluron, Teflubenzuron and Lufenuron on the Morphology and Physiology of Euschistus heros

The Neotropical brown stink bug, Euschistus heros (F.) (Heteroptera: Pentatomidae), is an important pest that damages soybean, especially in the central-west region of Brazil. The effect of insect growth regulator insecticides on fourth-instar nymphs and adults of the neotropical brown stink bug was evaluated under laboratory and greenhouse conditions, respectively. In the laboratory, the insecticides (doses in g a.i. ha-1) novaluron (20.0 and 40.0), teflubenzuron (26.2 and 52.5), and lufenuron (20.0 and 40.0), in addition to the control (water), were tested on fourth-instar nymphs of E. heros and their development were followed to adulthood. Mortality, number of adults with and without deformities, and fecundity were determined. In a greenhouse, the effects of the same insecticides on the adult of the stink bug were evaluated by determining the fecundity and viability of the eggs laid. The fourth-instar nymphs of E. heros, when exposed to either dose of the tested insecticides presented mortality and insects with deformations, as well as reduced fecundity of females that reached adulthood. In the trial with adult E. heros, all tested insecticides reduced stink bug fecundity. In the same way, the viability of the produced eggs was reduced in all the chemical treatments, except for novaluron at the lowest dose tested, in which egg viability did not differ from the control treatment. Based on the obtained results, one can infer that the growth-regulator insecticides evaluated, although usually more suitable for the control of caterpillars, can interfere negatively in the development and reproduction of the neotropical brown stink bug, thus constituting a complementary alternative for the management of this pest.

Fitting statistical probability distribution for evaporation in western Brazil

This study aims to find evaporation (ETo) probabilities for the central west region of Brazil, including Campo Grande, Cuiabá, Goiânia and Brasilia. In this case, a maximum likelihood estimation was used for the probability distributions adjusting to the monthly ETo from 1960 to 2020. The work estimates three probability distributions, including the Generalized Extreme Values (GEV), Gumbel (GUM) and Log-Normal (LN). The Kolmogorov-Smirnov test, the Akaike information criterion (AIC), the Bayesian information criterion (BIC), the root mean square error (RMSE) and the coefficient of determination (R2) were applied to measure the quality of the adjustment. The evapotranspiration forecasts were made for the return periods of 10, 30, 50, and 100 years. The GEV and GUM distributions are advised for use during the summer. Altering LN distribution to a sequence of ETo throughout the winter months is the best option. Moreover, deforestation, combustion, extensive fires, aerosol pollutants, and climate change are the primary causes of excessive ETo in the area under study.

Dynamic of Mayaro Virus Transmission in Aedes aegypti, Culex quinquefasciatus Mosquitoes, and a Mice Model.

Mayaro virus (MAYV) is transmitted by Haemagogus spp. mosquitoes and has been circulating in Amazon areas in the North and Central West regions of Brazil since the 1980s, with an increase in human case notifications in the last 10 years. MAYV introduction in urban areas is a public health concern as infections can cause severe symptoms similar to other alphaviruses. Studies with Aedes aegypti have demonstrated the potential vector competence of the species and the detection of MAYV in urban populations of mosquitoes. Considering the two most abundant urban mosquito species in Brazil, we investigated the dynamics of MAYV transmission by Ae. aegypti and Culex quinquefasciatus in a mice model. Mosquito colonies were artificially fed with blood containing MAYV and infection (IR) and dissemination rates (DR) were evaluated. On the 7th day post-infection (dpi), IFNAR BL/6 mice were made available as a blood source to both mosquito species. After the appearance of clinical signs of infection, a second blood feeding was performed with a new group of non-infected mosquitoes. RT-qPCR and plaque assays were carried out with animal and mosquito tissues to determine IR and DR. For Ae. aegypti, we found an IR of 97.5-100% and a DR reached 100% in both 7 and 14 dpi. While IR and DR for Cx. quinquefasciatus was 13.1-14.81% and 60% to 80%, respectively. A total of 18 mice were used (test = 12 and control = 6) for Ae. aegypti and 12 (test = 8 and control = 4) for Cx. quinquefasciatus to evaluate the mosquito-mice transmission rate. All mice that were bitten by infected Ae. aegypti showed clinical signs of infection while all mice exposed to infected Cx. quinquefasciatus mosquitoes remained healthy. Viremia in the mice from Ae. aegypti group ranged from 2.5 × 108 to 5 × 109 PFU/mL. Ae. aegypti from the second blood feeding showed a 50% IR. Our study showed the applicability of an efficient model to complete arbovirus transmission cycle studies and suggests that the Ae. aegypti population evaluated is a competent vector for MAYV, while highlighting the vectorial capacity of Ae. aegypti and the possible introduction into urban areas. The mice model employed here is an important tool for arthropod-vector transmission studies with laboratory and field mosquito populations, as well as with other arboviruses.

Life prediction of 6201-T81 aluminum alloy wires under fretting fatigue and variable amplitude loading

Fretting fatigue tests under variable amplitude loading were performed on 6201-T81 aluminum alloy wires of an AAAC 900 MCM conductor. The loading program consisted of a three-block loading history, defined using vibration data of a transmission line located in the center-west region of Brazil. Two previously developed methodologies for life prediction of wires under fretting fatigue, based on the Theory of Critical Distances and on a master fatigue curve, were extended to variable amplitude loading conditions. The good agreement between measured and predicted lives indicated that both methodologies can be useful for fatigue analysis of wires of overhead conductors.