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Light-Emitting Diodes (LEDs) have been effective light sources in attracting Anopheles mosquitoes, but the broad-spectrum white light, even with a wide-ranging application in lighting, have not been evaluated yet. In this study, the white light was field evaluated against the green one in the light trapping of anopheline mosquitoes by using two non-suction Silva traps and two CDC-type suction light traps. Anopheline mosquitoes were captured for two 21-night periods of collecting (2022 and 2023). In the first period, two LEDs were used per Silva trap, but three were used in the second one to increase the luminance/illuminance at traps. A CDC-type suction light trap equipped with an incandescent lamp was used in 2022 and a CDC-type suction light trap equipped with a 6 V-white light (higher luminance/illuminance) in 2023. A total of eight species and 3,289 specimens were captured in both periods. The most frequent species were Anopheles triannulatus s.l., An. goeldii, An. evansae and An. argyritarsis. In 2022, white LEDs were less attractive to anopheline mosquitoes than the other light sources, but without statistical difference among treatments (F = 2.703; P = 0.0752; df = 2). In 2023, even with an increased luminance/illuminance at traps, no statistical difference was found between the two LED-baited Silva traps (F = 6.690; P = 0.0024; df = 2), but rather between the 6 V-white-baited CDC-type suction light trap and green-baited Silva traps. Due to some drawbacks and the lower abundance of individuals caught by using white LEDs, the narrow-banded green LEDs is preferable to white ones for attracting anophelines.

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Aging causes impairment of contrast sensitivity and chromatic discrimination, leading to changes in the perceptual interactions between color and luminance information. We aimed to investigate the influence of chromatic noise on luminance contrast thresholds in young and older adults. Forty participants were divided equally into Young (29.6 ± 6.3-year-old) and Elderly Groups (57.8 ± 6.6-year-old). They performed a luminance contrast discrimination task in the presence of chromatic noise maskers using a mosaic stimulus in a mosaic background. Four chromatic noise masking protocols were applied (protan, deutan, tritan, and no-noise protocols). We found that luminance contrast thresholds were significantly elevated by the addition of chromatic noise in both age groups (P < 0.05). In the Elderly group, but not the younger group, thresholds obtained in the tritan protocol were lower than those obtained from protan and deutan protocols (P < 0.05). For all protocols, the luminance contrast thresholds of elderly participants were higher than in young people (P < 0.01). Tritan chromatic noise was less effective in inhibiting luminance discrimination in elderly participants.

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PURPOSE: Visual evoked cortical potentials (VECPs) are useful for investigating the mechanisms and dysfunctions of color vision. Chromatic sinusoidal gratings are generally used to elicit VECPs, but they require long psychophysical measurements to match the perceptual luminance between their stripes. An alternative method is to use pseudoisochromatic stimuli, which makes use of luminance noise to mask luminance clues and force the target perception to be dependent on chromatic contrast. In this study, we compared VECPs generated by sinusoidal gratings and pseudoisochromatic gratings. Contrary to chromatic sinusoidal gratings, pseudoisochromatic stimuli do not require the use of previous methods to find the equiluminance of the stimulus. METHODS: Normal trichromats were recruited to be tested with red-green chromatic sinusoidal gratings and pseudoisochromatic gratings presented by pattern onset-offset and pattern reversal modes in five spatial frequencies. In addition, we also tested four different chromatic contrast pairs in pattern onset-offset mode presentation in five trichromats and one colorblind subject (deuteranope). RESULTS: Pattern onset-offset VECPs elicited by sinusoidal gratings had a larger amplitude than those obtained with pseudoisochromatic stimuli, whereas pattern reversal VECPs elicited by pseudoisochromatic gratings had similar amplitudes compared to those elicited by sinusoidal gratings. We found no difference between the VECP amplitudes elicited by sinusoidal and pseudoisochromatic gratings containing different chromatic contrast. Color-blind subjects displayed absent or small responses to the stimuli. CONCLUSION: Pseudoisochromatic stimulus can be an alternative stimulus to generate VECPs dominated by the chromatic mechanism.

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Color vision assessment can be done using pseudoisochromatic stimuli, which has a luminance noise to eliminate brightness differences between the target and background of the stimulus. It is not clear the influence of the luminance noise on color discrimination. We investigated the effect of change in the luminance noise limits on color discrimination. Eighteen trichromats and ten congenital dichromats (eight protans, two deutans) had their color vision evaluated by the Cambridge Colour Test, and were genetically tested for diagnostic confirmation. The stimuli were composed of a mosaic of circles in a 5° circular field. A subset of the circles differed in chromaticity from the remaining field, forming a letter C. Color discrimination was estimated in stimulus conditions differing in luminance noise range: (i) 6-20 cd/m2; (ii) 8-18 cd/m2; (iii) 10-16 cd/m2; and (iv) 12-14 cd/m2. Six equidistant luminance values were used within the luminance noise limits with the mean stimulus luminance maintained constant under all conditions. A four-alternative, forced-choice method was applied to feed a staircase procedure to estimate color discrimination thresholds along eight chromatic axes. An ellipse model was adjusted to the eight color discrimination thresholds. The parameters of performance were threshold vector lengths and the ellipse area. Results were compared using the Kruskal-Wallis test with a significance level of 5%. The linear function model was applied to analyze the dependence of the discrimination parameters on the noise luminance limits. The first derivative of linear function was used as an indicator of the rate of change in color discrimination as a function of luminance noise changes. The rate of change of the ellipse area as a function of the luminance range in dichromats was higher than in trichromats (p < 0.05). Significant difference was also found for individual thresholds in half of the axes we tested. Luminance noise had a greater effect on color discrimination ability of dichromats than the trichromats, especially when the chromaticities were close to their protan and deutan color confusion lines.

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INTRODUCTION: The purpose of this study was to measure luminance contrast sensitivity and color vision thresholdfs in normal subjects using a blue light filter lens and transparent intraocular lens material. METHODS: Monocular luminance grating contrast sensitivity was measured with Psycho for Windows (version 2.36; Cambridge Research Systems) at 3.0, 6.0, 12.0, 20.0, and 30.0 cycles per degree of visual angle (cpd) in 15 normal subjects (eight female), with a mean age of 21.6 years (SD = 3.8 years). Chromatic discrimination was assessed with the Cambridge colour test (CCT) along the protan, deutan, and tritan color confusion axes. Both tests were performed in a darkened room under two situations: with a transparent lens and with blue light filter lens. Subjective impressions were taken by subjects regarding their visual experience under both conditions. RESULTS: No difference was found between the luminance contrast sensitivity measured with transparent and blue light filter. However, 13/15 (87%) of the subjects reported more comfortable vision with the blue filter. In the color vision test, tritan thresholds were significantly higher for the blue filter compared with the transparent filter (p = 0.003). For protan and deutan thresholds no differences were found. CONCLUSION: Blue-yellow color vision is impaired with the blue light filter, and no impairment occurs with the transparent filter. No significant differences in thresholds were found in the luminance contrast sensitivity comparing the blue light and transparent filters. The impact of short wavelength light filtering on intrinsically photosensitive retinal ganglion cells is also discussed.

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Pseudoisochromatic stimuli have been widely used to evaluate color discrimination and to identify color vision deficits. Luminance noise is one of the stimulus parameters used to ensure that subject's response is due to their ability to discriminate target stimulus from the background based solely on the hue between the colors that compose such stimuli. We studied the influence of contrast modulation of the stimulus luminance noise on threshold and reaction time color discrimination. We evaluated color discrimination thresholds using the Cambridge Color Test (CCT) at six different stimulus mean luminances. Each mean luminance condition was tested using two protocols: constant absolute difference between maximum and minimum luminance of the luminance noise (constant delta protocol, CDP), and constant contrast modulation of the luminance noise (constant contrast protocol, CCP). MacAdam ellipses were fitted to the color discrimination thresholds in the CIE 1976 color space to quantify the color discrimination ellipses at threshold level. The same CDP and CCP protocols were applied in the experiment measuring RTs at three levels of stimulus mean luminance. The color threshold measurements show that for the CDP, ellipse areas decreased as a function of the mean luminance and they were significantly larger at the two lowest mean luminances, 10 cd/m(2) and 13 cd/m(2), compared to the highest one, 25 cd/m(2). For the CCP, the ellipses areas also decreased as a function of the mean luminance, but there was no significant difference between ellipses areas estimated at six stimulus mean luminances. The exponent of the decrease of ellipse areas as a function of stimulus mean luminance was steeper in the CDP than CCP. Further, reaction time increased linearly with the reciprocal of the length of the chromatic vectors varying along the four chromatic half-axes. It decreased as a function of stimulus mean luminance in the CDP but not in the CCP. The findings indicated that visual performance using pseudoisochromatic stimuli was dependent on the Weber's contrast of the luminance noise. Low Weber's contrast in the luminance noise is suggested to have a reduced effect on chromatic information and, hence, facilitate desegregation of the hue-defined target from the background.

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In pseudoisochromatic stimuli the presence of spatial and luminance noise forces the subject to discriminate the target from the background solely on the basis of chromaticity difference. Color-blind subjects may show difficulty to identify the target due to the elimination of borders and brightness clues caused by the luminance and spatial noise. Few studies have fully described the features of pseudoisochromatic stimuli. Fewer investigators have focused their studies in the effects of specific pseudoisochromatic parameters on color discrimination. We used the Cambridge Color Test (CCT) to investigate the influence on color discrimination thresholds due to the number of luminance levels present in the luminance noise. The CCT default has six luminance steps; however, in our investigation a total of eight different conditions were tested from 2 to 16 luminance steps. It was found that the CCT provided very robust values for color discrimination thresholds, which were degraded only for very small number of luminance steps. When the number of steps was increased, the color discrimination thresholds improved from 2 to 6 luminance steps and gradually reached a plateau for 10 or more luminance steps. The area of color discrimination ellipses as a function of luminance steps matches the relative proportion of ineffective contrasts between mosaic patches as a function of luminance steps, assuming that contrast becomes ineffective for values 18.6% or less. The lower number of color and luminance interactions in these conditions could explain the measured increase of color discrimination thresholds. The primary conclusion from this investigation was that results from pseudoisochromatic tests should have their parameters described in more detail. This type of description would allow a better understanding of the results provided, interpretations, and therefore cross study comparison of results obtained from different laboratories.

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In this study, we examined whether luminance processing in the human visual system would exhibit any history effect (i.e., inter-trial modulation) in psychophysical and magnetoencephalographic experiments. A disk was presented against a black background at various luminance levels in a randomized order. During the MEG recording, participants were instructed to rate the brightness of the disk (magnitude estimation) and to report it aloud during inter-stimulus interval. The MEG results showed that the neuromagnetic activation around 200-220 ms after the stimulus onset in the left occipito-temporal regions at a given trial was weaker when the disk luminance in the immediately prior trial was higher. An inverse inter-trial effect was also observed in the psychophysical experiment. These findings suggest that the neuromagnetic activity reflects the inter-trial modulation of luminance processing that correlates with the subjective perception of brightness.

En este estudio, se examinó si el procesamiento de iluminación en el sistema visual humano exhibie algún efecto de historia (es decir, modulación inter-ensayo) en experimentos psicofísicos y de magnetoencefalografía (MEG). Un disco se presentó contra un fondo negro en varios niveles de iluminación en un orden aleatorio. Durante el registro de MEG, los participantes fueron instruidos para clasificar el brillo del disco (estimación de magnitud) y reportarlo durante el intervalo inter-ensayo. Los resultados de MEG mostraron que la activación neuromagnetica alrededor 200-220 ms después de la aparición de estímulo en las regiones occipito-temporal izquierda en un ensayo dade fue más débil cuando la iluminación de disco en el ensayo inmediatamente antes fue mayor. También se observó un efecto inverso inter-ensayo en el experimento psicofísico. Estos hallazgos sugieren que la actividad neuromagnética refleja la modulación inter-ensayo de procesamiento de iluminación que se correlaciona con la percepción subjetiva de brillo.

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PURPOSE: The present study aimed to compare the postoperative contrast sensitivity functions between wavefront-guided LASIK eyes and their contralateral wavefront-guided PRK eyes. METHODS: The participants were 11 healthy subjects (mean age=32.4 ± 6.2 years) who had myopic astigmatism. The spatial contrast sensitivity functions were measured before and three times after the surgery. Psycho and a Cambridge graphic board (VSG 2/4) were used to measure luminance, red-green, and blue-yellow spatial contrast sensitivity functions (from 0.85 to 13.1 cycles/degree). Longitudinal analysis and comparison between surgeries were performed. RESULTS: There was no significant contrast sensitivity change during the one-year follow-up measurements neither for LASIK nor for PRK eyes. The comparison between procedures showed no differences at 12 months postoperative. CONCLUSIONS: The present data showed similar contrast sensitivities during one-year follow-up of wave-front guided refractive surgeries. Moreover, one year postoperative data showed no differences in the effects of either wavefront-guided LASIK or wavefront-guided PRK on the luminance and chromatic spatial contrast sensitivity functions.

OBJETIVO: A proposta do presente estudo é comparar funções de sensibilidade ao contraste obtidas após wavefront-LASIK e wavefront-PRK no olho contralateral. MÉTODOS: Os participantes foram 11 sujeitos saudáveis (idade média=32,4 ± 6,2 anos) com astigmatismo miópico. As funções de sensibilidade ao contraste espacial foram obtidas antes e três vezes após a cirurgia. O programa Psycho e uma placa gráfica da Cambridge Research Systems (VSG 2/4) permitiram gerar os estímulos com contraste espacial de luminância e cromático (verde-vermelho e azul-amarelo) de 0,85 até 13,1 ciclos/grau. Análises longitudinais e comparações entre as cirurgias foram realizadas. RESULTADOS: Não houve mudança significativa da sensibilidade ao contraste durante o primeiro ano após a cirurgia para o olho que recebeu o LASIK ou para o olho que recebeu o PRK. A comparação entre as cirurgias também foi semelhante no pós-operatório de um ano. CONCLUSÕES: Os resultados apresentados mostraram sensibilidade ao contraste semelhante durante o primeiro ano após a cirurgia refrativa com o wavefront. Além disso, no pós-operatório de um ano não houve diferença nas funções de sensibilidade ao contraste de luminância e cromático entre os olhos que receberam LASIK e os que receberam PRK.

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OBJETIVO: Avaliar a qualidade dos monitores de diagnóstico e tratamento de imagem digital em radiologia convencional (raios X) com base nos níveis de luminância. Fez-se a medição da iluminância dos postos de trabalho onde estavam os monitores. MATERIAIS E MÉTODOS: A medição da luminância foi realizada usando-se um detector Unfors Xi Light em cinco instituições, com 23 monitores primários e 22 secundários, sendo 6 usados em urgência, seguindo o método descrito no relatório TG18 da American Association of Physicists in Medicine (AAPM). O instrumento de medida utilizado foi o Delta Ohm HD 9221 luximeter. RESULTADOS: Para as recomendações da AAPM, tanto monitores primários como secundários cumpriram, no geral, os níveis de tolerância. No caso dos níveis de iluminância, nos locais de trabalho dos monitores primários encontravam-se ligeiramente acima do intervalo recomendado. Quanto às recomendações do The Royal College of Radiologists (RCR), os monitores que respeitaram os níveis recomendados estavam em minoria, embora as diferenças não fossem significativas. CONCLUSÃO: Em geral, os resultados foram satisfatórios, embora os monitores não fossem adequados para atingir as recomendações exigentes do RCR. Os níveis de referência entre os monitores primários e secundários deveriam aproximar-se, de modo a garantir a qualidade de imagem. Os monitores para visualização e diagnóstico de imagens médicas devem ser regularmente avaliados para manter um sistema com a qualidade exigida, dada a função que desempenham.

OBJECTIVE: To evaluate the quality of primary and secondary displays of conventional radiography systems based on luminance measurements. The level of ambient lighting within the rooms was also measured. MATERIALS AND METHODS: Luminance measurements were performed with an Unfors Xi Light Detector in 23 primary and 22 secondary displays (six of them utilized in emergency departments) at five different institutions, and according to the method described on the American Association of Physicists in Medicine (AAPM) TG18 report. The level of ambient lighting was measured with Delta Ohm HD 9221 lux meter. RESULTS: In general, both the primary and secondary the displays were compliant with the AAPM guidelines. As regards ambient lighting, the primary workstation rooms were slightly above the recommended levels. As far as The Royal College of Radiologists (RCR) recommendations are concerned, the number of compliant displays corresponded to a minority, with no significant difference, though. CONCLUSION: Although most of the displays could not meet the strict RCR guidelines, in general, the results were satisfactory. The level of agreement between primary and secondary displays should be as high as possible in order to guarantee the image quality. Considering the key role played by diagnostic imaging systems, medical imaging displays must be regularly evaluated to assure that the quality of the imaging system is maintained.

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O objetivo deste estudo foi medir a função de sensibilidade ao contraste (FSC) de adultos jovens para frequências espaciais de grades senoidais verticais em condições de luminância fotópica e escotópica. Utilizou-se o método psicofísico da escolha forçada para estimativa da sensibilidade ao contraste para as frequências de 0,6, 2,5 e 5,0 cpg. Todos os participantes apresentavam acuidade visual normal ou corrigida e estavam livres de doenças oculares identificáveis. As análises estatísticas mostraram que houve diferenças entre as condições de luminância e que os adultos foram mais sensíveis às frequências média e alta na condição de luminância fotópica. Esses resultados indicam que as características do sistema visual humano para detectar frequências espaciais em condições de luminância fotópica e escotópica passam por mecanismos distintos que tornam possível a diferenciação de contraste.

The aim of this study was to measure the contrast sensitivity function (CSF) of young adults for spatial frequencies of vertical sine-wave gratings in terms of photopic and scotopic luminance. We used the forced-choice psychophysical method to estimate contrast sensitivity for frequencies of 0.6, 2.5 and 5.0 cpd. All participants had normal or corrected acuity and they were free of ocular pathologies. Statistical analysis showed that there were differences between the conditions of luminance, where adults were more sensitive to middle and high frequencies in the photopic luminance condition. These results indicate that the characteristics of human visual system to detect spatial frequencies in photopic conditions of luminance and scotopic pass through distinct mechanisms that make possible the differentiation of contrast.

El objetivo de este estudio fue medir la función de sensibilidad al contraste (FSC) de los adultos jóvenes para frecuencias espaciales de las verticales redes sinusoidales en condiciones de luminosidad fotópica y escotópica. Se utilizó el método psicofísico de elección forzada para estimar la sensibilidad al contraste para las frecuencias de 0,6, 2,5 y 5,0 cpg. Todos los participantes presentaban acuidad visual normal o corigida y estaban libres de patología ocular. El análisis estadístico mostró que hay diferencias entre las condiciones de luminancia, y que los adultos son más sensibles a las frecuencias medias y altas en la condición de luminancia fotópica. Estos resultados indican que las características del sistema visual humano para la detección de frecuencias espaciales en condiciones de luminancia fotópica y escotópica pasan por diferentes mecanismos que hacen posible la diferenciación de contraste.

RESUMO

O objetivo deste estudo foi medir a função de sensibilidade ao contraste (FSC) de adultos jovens para frequências espaciais de grades senoidais verticais em condições de luminância fotópica e escotópica. Utilizou-se o método psicofísico da escolha forçada para estimativa da sensibilidade ao contraste para as frequências de 0,6, 2,5 e 5,0 cpg. Todos os participantes apresentavam acuidade visual normal ou corrigida e estavam livres de doenças oculares identificáveis. As análises estatísticas mostraram que houve diferenças entre as condições de luminância e que os adultos foram mais sensíveis às frequências média e alta na condição de luminância fotópica. Esses resultados indicam que as características do sistema visual humano para detectar frequências espaciais em condições de luminância fotópica e escotópica passam por mecanismos distintos que tornam possível a diferenciação de contraste.(AU)

The aim of this study was to measure the contrast sensitivity function (CSF) of young adults for spatial frequencies of vertical sine-wave gratings in terms of photopic and scotopic luminance. We used the forced-choice psychophysical method to estimate contrast sensitivity for frequencies of 0.6, 2.5 and 5.0 cpd. All participants had normal or corrected acuity and they were free of ocular pathologies. Statistical analysis showed that there were differences between the conditions of luminance, where adults were more sensitive to middle and high frequencies in the photopic luminance condition. These results indicate that the characteristics of human visual system to detect spatial frequencies in photopic conditions of luminance and scotopic pass through distinct mechanisms that make possible the differentiation of contrast.(AU)

El objetivo de este estudio fue medir la función de sensibilidad al contraste (FSC) de los adultos jóvenes para frecuencias espaciales de las verticales redes sinusoidales en condiciones de luminosidad fotópica y escotópica. Se utilizó el método psicofísico de elección forzada para estimar la sensibilidad al contraste para las frecuencias de 0,6, 2,5 y 5,0 cpg. Todos los participantes presentaban acuidad visual normal o corigida y estaban libres de patología ocular. El análisis estadístico mostró que hay diferencias entre las condiciones de luminancia, y que los adultos son más sensibles a las frecuencias medias y altas en la condición de luminancia fotópica. Estos resultados indican que las características del sistema visual humano para la detección de frecuencias espaciales en condiciones de luminancia fotópica y escotópica pasan por diferentes mecanismos que hacen posible la diferenciación de contraste.(AU)

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Avaliou-se o efeito do ambiente de produção sobre o desempenho produtivo e respostas fisiológicas de frangos de corte demarca comercial sexados, machos e fêmeas. Os frangos foram criados em duas alas separadas no interior de um galpão comercial com sistemas de ventilação convencional e nebulização. O ambiente produtivo foi avaliado por meio do índice de temperatura do globo negro e umidade, da intensidade de ruído e do nível de iluminância. A avaliação dos animais foi feita por meio das respostas fisiológicas - frequência respiratória, temperatura retal, temperatura da pele e temperatura da pena - e produtivas - ganho de peso semanal, massa corporal e mortalidade. Os machos apresentaram desempenho produtivo superior às fêmeas (P<0,05). A massa corporal média dos machos foi 214,6g maior que a das fêmeas aos 35 dias de vida, a qual se igualou à massa corporal dos machos somente aos 38,47 dias de vida. As respostas fisiológicas não se relacionaram com o ambiente.(AU)

The effect of the production environment on the productive performance and physiological responses of sexed broiler chickens, male and female, was evaluated. The birds were raised in two separate regions inside the broiler house. The productive environment was determined using the black-globe temperature humidity index, as well as noise and luminance levels. The physiological responses (breath rate, rectal temperature, skin temperature and feather temperature) and productive responses (weekly weight gain, body mass and mortality) were used to evaluate the effect of the production environment on the broilers raised in a house equipped with conventional and misting ventilation systems. The mean body mass of the males was 214.6 g greater than females at 35 days of life, which became equal to the male mean body mass only at 38.47 days of life. The physiological responses were not related to the environment.(AU)

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Avaliou-se o efeito do ambiente de produção sobre o desempenho produtivo e respostas fisiológicas de frangos de corte demarca comercial sexados, machos e fêmeas. Os frangos foram criados em duas alas separadas no interior de um galpão comercial com sistemas de ventilação convencional e nebulização. O ambiente produtivo foi avaliado por meio do índice de temperatura do globo negro e umidade, da intensidade de ruído e do nível de iluminância. A avaliação dos animais foi feita por meio das respostas fisiológicas - frequência respiratória, temperatura retal, temperatura da pele e temperatura da pena - e produtivas - ganho de peso semanal, massa corporal e mortalidade. Os machos apresentaram desempenho produtivo superior às fêmeas (P<0,05). A massa corporal média dos machos foi 214,6g maior que a das fêmeas aos 35 dias de vida, a qual se igualou à massa corporal dos machos somente aos 38,47 dias de vida. As respostas fisiológicas não se relacionaram com o ambiente.

The effect of the production environment on the productive performance and physiological responses of sexed broiler chickens, male and female, was evaluated. The birds were raised in two separate regions inside the broiler house. The productive environment was determined using the black-globe temperature humidity index, as well as noise and luminance levels. The physiological responses (breath rate, rectal temperature, skin temperature and feather temperature) and productive responses (weekly weight gain, body mass and mortality) were used to evaluate the effect of the production environment on the broilers raised in a house equipped with conventional and misting ventilation systems. The mean body mass of the males was 214.6 g greater than females at 35 days of life, which became equal to the male mean body mass only at 38.47 days of life. The physiological responses were not related to the environment.

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