Mercury toxicity in the Amazon: contrast sensitivity and color discrimination of subjects exposed to mercury

We measured visual performance in achromatic and chromatic spatial tasks of mercury-exposed subjects and compared the results with norms obtained from healthy individuals of similar age. Data were obtained for a group of 28 mercury-exposed subjects, comprising 20 Amazonian gold miners, 2 inhabitants of Amazonian riverside communities, and 6 laboratory technicians, who asked for medical care. Statistical norms were generated by testing healthy control subjects divided into three age groups. The performance of a substantial proportion of the mercury-exposed subjects was below the norms in all of these tasks. Eleven of 20 subjects (55%) performed below the norms in the achromatic contrast sensitivity task. The mercury-exposed subjects also had lower red-green contrast sensitivity deficits at all tested spatial frequencies (9/11 subjects; 81%). Three gold miners and 1 riverine (4/19 subjects, 21%) performed worse than normal subjects making more mistakes in the color arrangement test. Five of 10 subjects tested (50%), comprising 2 gold miners, 2 technicians, and 1 riverine, performed worse than normal in the color discrimination test, having areas of one or more MacAdam ellipse larger than normal subjects and high color discrimination thresholds at least in one color locus. These data indicate that psychophysical assessment can be used to quantify the degree of visual impairment of mercury-exposed subjects. They also suggest that some spatial tests such as the measurement of red-green chromatic contrast are sufficiently sensitive to detect visual dysfunction caused by mercury toxicity.

Detecção laboratorial de Chlamydia trachomatis em escolares da rede pública do estado do Pará com diagnóstico clínico de tracoma

O tracoma como principal causa de cegueira prevenível no mundo, é uma doença negligenciada relacionada a baixas condições socioeconômicas e locais sem saneamento básico. Presente principalmente nos países subdesenvolvidos traz grandes prejuízos aos cofres públicos com a perda de produtividade e a deficiência visual. Com a criação da Aliança para Eliminação Global de Tracoma em 1997 (GET2020), o Estado do Pará, com apoio do Ministério da Saúde do Brasil, realizaram em 2006 o inquérito epidemiológico do tracoma em escolares de 1ª a 4ª série da rede oficial de ensino, nos municípios com índice de desenvolvimento humano inferior a média nacional, para conhecer a prevalência da doença. Os dados obtidos no inquérito comprovaram que a doença não foi erradicada, revelando 35 municípios paraenses prioritários e prevalências acima de 5%. Uma sub-amostra da conjuntiva de escolares clinicamente positivos foi coletada para a confirmação diagnóstica por Imunofluorescência direta (IFD). O presente estudo utilizou 52 amostras crio conservadas obtidas durante o inquérito, para serem analisadas pelos métodos de IFD e de biologia molecular, na identificação laboratorial da Chlamydia trachomatis. Foram encontradas as frequências de 26,92% (14/52) e 49% (24/49) de resultados positivos pelas técnicas de IFD e reação em cadeia da polimerase (nested-PCR), respectivamente. Considerando as 49 amostras analisadas pelas duas metodologias, as sensibilidades para a detecção do agente etiológico, por IFD e PCR foram de 28,57% (14/49) e 48,98% (24/49), respectivamente (p = 0,0127). As duas técnicas juntas confirmaram a infecção em 57,14% (n=28) das amostras, onde 50% (n=14) foram positivas apenas pela PCR, 35,72% (n=10) para ambas as técnicas e 14,28% (n=4) somente pela IFD. A análise de sete sequências nucleotídicas demonstrou homologia para isolados de C. trachomatis genótipo L1. Este estudo é pioneiro no Brasil, pois além de confirmar a presença de C. trachomatis em amostras oculares de escolares clínicamente positivos para tracoma, validou protocolo de obtenção de DNA a partir de lâminas de IFD crioconservadas, demonstrou a maior sensibilidade do método molecular frente à IFD e identificou o genótipo L1 presente nas amostras.

Division of labor between M and P visual pathways: different visual pathways minimize joint entropy differently

Visual perception and action are strongly linked with parallel processing channels connecting the retina, the lateral geniculate nucleus, and the input layers of the primary visual cortex. Achromatic vision is provided by at least two of such channels formed by the M and P neurons. These cell pathways are similarly organized in primates having different lifestyles, including species that are diurnal, nocturnal, and which exhibit a variety of color vision phenotypes. We describe the M and P cell properties by 3D Gábor functions and their 3D Fourier transform. The M and P cells occupy different loci in the Gábor information diagram or Fourier Space. This separation allows the M and P pathways to transmit visual signals with distinct 6D joint entropy for space, spatial frequency, time, and temporal frequency. By combining the M and P impacts on the cortical neurons beyond V1 input layers, the cortical pathways are able to process aspects of visual stimuli with a better precision than it would be possible using the M or P pathway alone. This performance fulfils the requirements of different behavioral tasks.

Avaliação do controle postural e do tipo do pé de pessoas com deficiência visual

The balance changing in the visually impaired is target of investigations, as balance and vision are interrelated. Also, another important factor in the maintenance of postural control is the biomechanical aspect of the feet. This study aimed to evaluate postural control and feet type of individuals with visual impairments. For then 17 adults with visual impairment participated in this study and have been evaluated by the baropodometry system. The oscillation of the center of pressure data were analyzed using the software Conformat Research 5.8, and subjected to Mann-Whitney’s statistical test. The results showed no statistically significant difference in postural control when comparing individuals with and without visual residue and which normal and foot with biomechanical alterations, which demonstrates that the visual impairment was the main factor of changes in postural control for the participants of this study.

Verbal and visual stimulation effects on rectus femoris and biceps femoris muscles during isometric and concentric

Background: Coactivation may be both desirable (injury prevention) or undesirable (strength measurement). In this context, different styles of muscle strength stimulus have being investigated. In this study we evaluated the effects of verbal and visual stimulation on rectus femoris and biceps femoris muscles contraction during isometric and concentric. Methods: We investigated 13 men (age =23.1 ± 3.8 years old; body mass =75.6 ± 9.1 kg; height =1.8 ± 0.07 m). We used the isokinetic dynamometer BIODEX device and an electromyographic (EMG) system. We evaluated the maximum isometric and isokinetic knee extension and flexion at 60°/s. The following conditions were evaluated: without visual nor verbal command (control); verbal command; visual command and; verbal and visual command. In relation to the concentric contraction, the volunteers performed five reciprocal and continuous contractions at 60°/s. With respect to isometric contractions it was made three contractions of five seconds for flexion and extension in a period of one minute. Results: We found that the peak torque during isometric flexion was higher in the subjects in the VVC condition (p > 0.05). In relation to muscle coactivation, the subjects presented higher values at the control condition (p > 0.05). Conclusion: We suggest that this type of stimulus is effective for the lower limbs.

Strategies used by the children's education teacher for orientation and mobility of the visually impaired student

This study aims to identify, describe, and analyse strategies used by a teacher to support the mobility of students with visual impairment in various school environments. A female student with visual impairment in Brazil, aged 5 years, and her classroom teacher participated in the study. Their interactions were videotaped, and later, their dialogue and actions were transcribed. Six themes of analysis were elaborated, one for each support strategy used by the teacher. The results revealed that the strategies employed by the teacher often hampered the child’s orientation and mobility. This was probably the result of a lack of assistance by professionals specialised in Orientation and Mobility, as stipulated in Brazilian legislation.

The phonological and visual basis of developmental dyslexia in Brazilian Portuguese reading children

Evidence from opaque languages suggests that visual attention processing abilities in addition to phonological skills may act as cognitive underpinnings of developmental dyslexia. We explored the role of these two cognitive abilities on reading fluency in Brazilian Portuguese, a more transparent orthography than French or English. Sixty-six children with developmental dyslexia and normal Brazilian Portuguese children participated. They were administered three tasks of phonological skills (phoneme identification, phoneme, and syllable blending) and three visual tasks (a letter global report task and two non-verbal tasks of visual closure and visual constancy). Results show that Brazilian Portuguese children with developmental dyslexia are impaired not only in phonological processing but further in visual processing. The phonological and visual processing abilities significantly and independently contribute to reading fluency in the whole population. Last, different cognitively homogeneous subtypes can be identified in the Brazilian Portuguese population of children with developmental dyslexia. Two subsets of children with developmental dyslexia were identified as having a single cognitive disorder, phonological or visual; another group exhibited a double deficit and a few children showed no visual or phonological disorder. Thus the current findings extend previous data from more opaque orthographies as French and English, in showing the importance of investigating visual processing skills in addition to phonological skills in children with developmental dyslexia whatever their language orthography transparency.

Orientação espacial em pessoas com deficiência visual: um estudo de triangulação por meio de monitoramento remoto

This study was conducted to investigate how visually impaired people perform distance estimation tasks by movement and navigation during deprivation of effective perceptual and proprioceptive information. For that they performed the task of walking three distances, being the first and second of 100 meters and the third of 140 meters (triangulation) from a point of origin in open field on a inverted L shaped trajectory and then returning to the origin. The first and second tasks were driven by means of a guide with GPS adapted to the study coordinates, and the third one was freeform with three sessions, the first without perceptual and proprioceptive restrictions, the second without auditory perception, and the third in a wheelchair, without proprioception. The objective of this study was to indicate the differences in distance reproduction in relation to accuracy and investigate the spatial representation of participants in a navigation task, in which there is active movement, but no effective perceptual and proprioceptive information. Results showed that the average participants underestimated distances producing average angles close to the value of 45°. And by means of the "t" students test no significant differences between subjects can be pointed out. To achieve these results we used remote monitoring by GPS and software TrackMaker.

Reliability of marginal microleakage assessment by visual and digital methods

The aim of this study was to investigate the reliability of visual and digital methods to assess marginal microleakage in vitro. Materials and Methods: Typical Class V preparations were made in bovine teeth and filled with composite resin. After dye penetration (0.5% basic fuchsin), teeth were sectioned and the 53 obtained fragments were assessed according to visual (stereomicroscope) and digital methods (Image Tool Software ® -ITS) (University of Texas Health Science Center-San Antonio Dental School, USA). Two calibrated examiners (A and B) evaluated dye penetration, by means of a stereomicroscope with ×20 magnification (scores), and by the ITS (millimeters). The intra- and inter-examiner agreement was estimated according to Kappa statistics (κ), and intraclass correlation coefficient (ρ). Results: In relation to the visual method, the intra-examiner agreement was almost perfect (κA = 0.87) and substantial (κB = 0.76), respectively to the examiner A and B. The inter-examiner agreement showed an almost perfect reliability (κ = 0.84). For the digital method, the intra-examiner agreement was almost perfect for both examiners and equal to ρ = 0.99, and so was the inter-examiner agreement value. Conclusion: Visual (stereomicroscope) and digital methods (ITS) showed high levels of intra- and inter-examiner reproducibility when marginal microleakage was assessed.

Desenvolvimento e aplicação de uma maquete sobre as leis de Kepler para inclusão de alunos com deficiência visual no ensino de física

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contextos comunicacionais adequados e inadequados à inclusão de alunos com deficiência visual em aulas de mecânica

This article is inserted in a study aimed at the identification of the main barriers for the inclusion of visually-impaired students in Physics classes. It focuses on the understanding of the communication context which facilitates or hardens the effective participation of students with visual impairment in Mechanics activities. To do so, the research defines, from empirical - sensory and semantic structures, the language to be applied in the activities, as well as, the moment and the speech pattern in which the languages have been used. As a result, it identifies the rela tion between the uses of the interdependent audio-visual empirical lan guage structure in the non-interactive episodes of authority; the decrease in the use of this structure in interactive episodes; the creation of educa tional segregation environments within the classroom and the frequent use of the interdependent tactile-hearing empirical language structure in such environments.

Contextos comunicacionais adequados e inadequados à inclusão de alunos com deficiência visual em aulas de termologia

This article represents a continuation of the results of a research presented in Camargo and Nardi (2007). It is inserted in the study that seeks to understand the main student’s inclusion barriers with visual impairment in the Physics classes. It aims to understand which communication context shows kindness or unkindness to the impairment visual student’s real participation in thermology activities. For this, the research defines, from the empirical - sensory and semantics structures, the used languages in the activities, as well, the moment and the speech pattern in which the languages have been used. As result, identifies a strong relation between the uses of the interdependent empirical structure audio-visual language in the non-interactive episodes of authority; a decrease of this structure use in the interactive episodes and the creation of education segregation environments within the classroom.

Análise das dificuldades e viabilidades para a inclusão do aluno com deficiência visual em aulas de termologia

This article is part of a study that seeks to understand what are the main barriers and alternatives for inclusion of students with visual impairments in the context of physics education. Presents and discusses the difficulties and feasibility to include the blind for birth student in thermology’ classes. Through content analysis identifies four classes of functioning implies difficulties and feasibility. In conclusion, emphasizes the importance of creating appropriate communication environments, the inclusive function of element interactivity, as well as the need for dismissal of a segregated environment within the classroom.

Educação inclusiva: concepções de professores de ciências com relação à inclusão de alunos com deficiência visual em aulas de astronomia

Despite of intense discussion over recent decades about the inclusion of disabled people and the influence of conception of teachers about that inclusion for the effectuation of it, this work sought to identify conceptions of science teachers regarding the inclusion of students with visual impairment in the classes of astronomy providing basis for future studies.

Aplicação de texto paradidático no ensino de física como possível alternativa para a inclusão de aluno com deficiência visual

The work completed on the use of para-didactic texts do not address the issue of education in a state that considers the presence of students with visual impairments. Therefore, this article discusses an innovative situation, investigating if the use of para-didactic texts provide the necessary conditions for the inclusion of students with visual impairment in physics education classes. The response indicates a discreet participation of these students, however a significant one, in this application the students were motivated and interested in all of the topics discussed. This prudent participation may have occurred for reasons such as shyness and the behavior of teachers, as they tended to to be more talkative to these students.