Cognitive Auditory Evoked Potentials in Investigation of Hearing Discrimination

Preattentive perception of occasional deviating stimuli in the stream of standard stimuli can be recorded with cognitive event-related potential (ERP) mismatch negativity (MMN). The earlier detection of stimuli at the auditory cortex can be examined with N1 and P2 ERPs. The MMN recording does not require co-operation, it correlates with perceptual threshold, and even complex sounds can be used as stimuli. The aim of this study was to examine different aspects that should be considered when measuring discrimination of hearing with ERPs. The MMN was found to be stimulusintensity- dependent. As the intensity of sine wave stimuli was increased from 40 to 80 dB HL, MMN mean amplitudes increased. The effect of stimulus frequency on the MMN was studied so that the pitch difference would be equal in each stimulus block according to the psychophysiological mel scale or the difference limen of frequency (DLF). However, the blocks differed from each other. The contralateral white noise masking (50 dB EML) was found to attenuate the MMN amplitude when the right ear was stimulated. The N1 amplitude was attenuated and, in contrast, P2 amplitude was not affected by contralateral white noise masking. The perception and production of vowels by four postlingually deafened patients with a cochlear implant were studied. The MMN response could be elicited in the patient with the best vowel perception abilities. The results of the studies show that concerning the MMN recordings, the stimulus parameters and recording procedure design have a great influence on the results.

Väriavaruuden rakenteen muokkaaminen yhtenäisyyden parantamiseksi

Pienien värierojen mittaamiseen käytetään CIE:n (The International Commission on Illumination) kehittämää ja standardoitua CIELAB – väriavaruutta ja sille suunniteltua CIEDE2000 – värieromittaria. CIELAB ei kuitenkaan ole täysin yhtenäinen ja siksi mittareita joudutaan virittämään sopivammiksi tähän väriavaruuteen. Työssä tutkitaan millä tavoin CIELAB - väriavaruutta voitaisiin korjata, jotta siitä saataisiin yhtenäisempi ja yksinkertainen ja virittämättömämpi värieromittari toimisi siinä paremmin. Työn tuloksena saatu muokattu väriavaruus paransi yhtenäisyyttä keskimäärin kymmenen prosenttia, mikä on liian vähän kun tavoitteena oli 30 - 50 prosenttia.

Holstein white coat color and performance: phenotypic, genetic and environmental correlations

Correlations of measures of percentages of white coat color, five measures of production and two measures of reproduction were obtained from 4293 first lactation Holsteins from eight Florida dairy farms. Percentages of white coat color were analyzed as recorded and transformed by an extension of Box-Cox procedures. Statistical analyses were by derivative-free restricted maximum likelihood (DFREML) with an animal model. Phenotypic and genetic correlations of white percentage (not transformed) were with milk yield, 0.047 and 0.097; fat yield, 0.002 and 0.004; fat percentage, -0.047 and -0.090; protein yield, 0.024 and 0.048; protein percentage, -0.070 and -0.116; days open, -0.012 and -0.065; and calving interval, -0.007 and -0.029. Changes in magnitude of correlations were very small for all variables except days open. Genetic and phenotypic correlations of transformed values with days open were -0.027 and -0.140. Modest positive correlated responses would be expected for white coat color percentage following direct selection for milk, fat, and protein yields, but selection for fat and protein percentages, days open, or calving interval would lead to small decreases.

Developmental norms for eight instruments used in the neuropsychological assessment of children: studies in Brazil

Norms for a battery of instruments, including Denckla's and Garfield's tests of Motor Persistence, Benton's Right-Left Discrimination, two recall modalities (Immediate and Delayed) of the Bender Test, Wechsler's Digit Span, the Color Span Test and the Human Figure Drawing Test, were developed for the neuropsychological assessment of children in the greater Rio de Janeiro area. Additionally, the behavior of each child was assessed with the Composite Teacher Rating Scale (Brito GNO and Pinto RCA (1991) Journal of Clinical and Experimental Neuropsychology, 13: 417-418). A total of 398 children (199 boys and 199 girls balanced for age) with a mean age of 9.3 years (SD = 2.8), who were attending a public school in Niterói, were the subjects of this study. Gender and age had significant effects on performance which depended on the instrument. Nonachievers performed worse than achievers in most neuropsychological tests. Comparison of our data to the available counterparts in the United States revealed that American children outperformed Brazilian children on the Right-Left Discrimination, Forward Digit Span, Color Span and Human Figure Drawing Tests. Further analysis showed that the neurobehavioral data consist of different factorial dimensions, including Human Body Representation, Motor Persistence of the Legs, Orbito-Orobuccal Motor Persistence, Attention-Memory, Visuospatial Memory, Neuropsychomotor Speed, Hyperactivity-Inattention, and Anxiety-Negative Socialization. We conclude that gender and age should be taken into account when using the normative data for most of the instruments studied in the present report. Furthermore, we stress the need for major changes in the Brazilian public school system in order to foster the development of secondary cognitive abilities in our children

Comparison of Pavlovian serial conditional discrimination in rats and hamsters in the same experimental situation

The present study compares behavioral changes between two distinct rodent groups, hamsters (Mesocricetus auratus) and Wistar rats, when submitted in the same homogeneous experimental situations to a serial conditional discrimination procedure which involves water deprivation and the processing of temporal variables. Both hamsters and rats acquired serial positive conditional discrimination as indicated by higher frequencies of magazine-oriented behavior during the tone followed by reinforcement (T+) and preceded by the feature stimulus light (L) and during the empty interval, than during the tone alone not followed by reinforcement (T-). Rats' frequencies of magazine-oriented behavior were high during T+ and T-, initially during training, and decreased during T- as the training progressed. However, the hamsters' frequencies of magazine-oriented behavior started very low and increased only during T+ as the training progressed. Comparison of the frequencies of magazine-oriented behavior during the empty interval in relation to the frequencies during the preceding L period showed that rats' frequencies remained very high and hamsters' frequencies increased during training. These results suggest that rats and hamsters have different behavioral strategies for the acquisition of a conditional discrimination. The results of the comparisons made in these experiments support the view of the importance of an ecological psychology approach to the understanding of complex learning in animals.

Eye color as an indicator of social rank in the fish Nile tilapia

We investigated the association of eye color with the dominant-subordinate relationship in the fish Nile tilapia, Oreochromis niloticus. Eye color pattern was also examined in relation to the intensity of attacks. We paired 20 size-matched fish (intruder: 73.69 ± 11.49 g; resident: 75.42 ± 8.83 g) and evaluated eye color and fights. These fish were isolated in individual aquaria for 10 days and then their eye color was measured 5 min before pairing (basal values). Twenty minutes after pairing, eye color and fights were quantified for 10 min. Clear establishment of social hierarchy was observed in 7 of 10 pairs of fish. Number of attacks ranged from 1 to 168 among pairs. The quartile was calculated for these data and the pairs were then divided into two classes: low-attack (1 to 111 attacks - 2 lower quartiles) or high-attack (112 to 168 attacks - 2 higher quartiles). Dominance decreased the eye-darkening patterns of the fish after pairing, while subordinance increased darkening compared to dominance. Subordinate fish in low-attack confrontations presented a darker eye compared to dominant fish and to the basal condition. We also observed a paler eye pattern in dominants that shared low-attack interactions after pairing compared to the subordinates and within the group. However, we found no differences in the darkening pattern between dominants and subordinates from the high-attack groups. We conclude that eye color is associated with social rank in this species. Moreover, the association between eye color and social rank in the low-attack pairs may function to reduce aggression.

Statistical segmentation methods and color variance analysis of retinal images

In this research, the effectiveness of Naive Bayes and Gaussian Mixture Models classifiers on segmenting exudates in retinal images is studied and the results are evaluated with metrics commonly used in medical imaging. Also, a color variation analysis of retinal images is carried out to find how effectively can retinal images be segmented using only the color information of the pixels.

Environmental color affects Nile tilapia reproduction

We investigated the effects of environmental color on the reproductive behavior of Nile tilapia, Oreochromis niloticus. Two environmental colors were tested by covering the aquarium (60 x 60 x 40 cm) with white (12 groups) or blue (13 groups) cellophane and observing reproductive behavior in groups of 2 males (10.27 ± 0.45 cm) and 3 females (10.78 ± 0.45 cm) each. After assignment to the respective environmental color (similar luminosity = 100 to 120 Lux), the animals were observed until reproduction (identified by eggs in the female's mouth) or up to 10 days after the first nest building. Photoperiod was from 6:00 h to 18:00 h every day. Food was offered in excess once a day and water quality was similar among aquaria. Daily observations were made at 8:00, 11:00, 14:00 and 17:00 h regarding: a) latency to the first nest, b) number of nests, c) gravel weight removed (the male excavates the nest in the bottom of the aquarium), d) nest area, and e) mouthbrooding incubation (indication of reproduction). The proportion of reproducing fish was significantly higher (6 of 13) in the group exposed to the blue color compared the group exposed to the white color (1 of 12; Goodman's test of proportions). Moreover, males under blue light removed significantly larger masses of gravel (blue = 310.70 ± 343.50 g > white = 130.38 ± 102.70 g; P = 0.01) and constructed wider nests (blue = 207.93 ± 207.80 cm² > white = 97.68 ± 70.64 cm²; P = 0.03) than the control (white). The other parameters did not differ significantly between light conditions. We concluded that reproduction in the presence of blue light was more frequent and intense than in the presence of white light.

Blood flow measurements in rats using four color microspheres during blockade of different vasopressor systems

The use of colored microspheres to adequately evaluate blood flow changes under different circumstances in the same rat has been validated with a maximum of three different colors due to methodological limitations. The aim of the present study was to validate the use of four different colors measuring four repeated blood flow changes in the same rat to assess the role of vasopressor systems in controlling arterial pressure (AP). Red (150,000), white (200,000), yellow (150,000), and blue (200,000) colored microspheres were infused into the left ventricle of 6 male Wistar rats 1) at rest and 2) after vasopressin (aAVP, 10 µg/kg, iv), 3) renin-angiotensin (losartan, 10 mg/kg, iv), and 4) sympathetic system blockade (hexamethonium, 20 mg/kg, iv) to determine blood flow changes. AP was recorded and processed with a data acquisition system (1-kHz sampling frequency). Blood flow changes were quantified by spectrophotometry absorption peaks for colored microsphere components in the tissues evaluated. Administration of aAVP and losartan slightly reduced the AP (-5.7 ± 0.5 and -7.8 ± 1.2 mmHg, respectively), while hexamethonium induced a 52 ± 3 mmHg fall in AP. The aAVP injection increased blood flow in lungs (78%), liver (117%) and skeletal muscle (>150%), while losartan administration enhanced blood flow in heart (126%), lungs (100%), kidneys (80%), and gastrocnemius (75%) and soleus (94%) muscles. Hexamethonium administration reduced only kidney blood flow (50%). In conclusion, four types of colored microspheres can be used to perform four repeated blood flow measurements in the same rat detecting small alterations such as changes in tissues with low blood flow.

Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images

The present study describes an auxiliary tool in the diagnosis of left ventricular (LV) segmental wall motion (WM) abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN) was developed and validated for grading LV segmental WM using data from color kinesis (CK) images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from two-dimensional images and scored them as: 1) normal, 2) mild hypokinesia, 3) moderate hypokinesia, 4) severe hypokinesia, 5) akinesia, and 6) dyskinesia. Based on expert analysis of 10 normal subjects and 10 patients, we trained a multilayer perceptron ANN using a back-propagation algorithm to provide automated grading of LVWM, and this ANN was then tested in the remaining subjects. Excellent concordance between expert and ANN analysis was shown by ROC curve analysis, with measured area under the curve of 0.975. An excellent correlation was also obtained for global LV segmental WM index by expert and ANN analysis (R² = 0.99). In conclusion, ANN showed high accuracy for automated semi-quantitative grading of WM based on CK images. This technique can be an important aid, improving diagnostic accuracy and reducing inter-observer variability in scoring segmental LVWM.

Racial inequalities and perinatal health in the southeast region of Brazil

Few studies are available about racial inequalities in perinatal health in Brazil and little is known about whether the existing inequality is due to socioeconomic factors or to racial discrimination per se. Data regarding the Ribeirão Preto birth cohort, Brazil, whose mothers were interviewed from June 1, 1978 to May 31, 1979 were used to answer these questions. The perinatal factors were obtained from the birth questionnaire and the ethnic data were obtained from 2063 participants asked about self-reported skin color at early adulthood (23-25 years of age) in 2002/2004. Mothers of mulatto and black children had higher rates of low schooling (£4 years, 27.2 and 38.0%) and lower family income (£1 minimum wage, 28.6 and 30.4%). Mothers aged less than 20 years old predominated among mulattos (17.0%) and blacks (14.0%). Higher rates of low birth weight and smoking during pregnancy were observed among mulatto individuals (9.6 and 28.8%). Preterm birth rate was higher among mulattos (9.5%) and blacks (9.7%) than whites (5.5%). White individuals had higher rates of cesarean delivery (34.9%). Skin color remained as an independent risk factor for low birth weight (P < 0.001), preterm birth (P = 0.01), small for gestational age (P = 0.01), and lack of prenatal care (P = 0.02) after adjustment for family income and maternal schooling, suggesting that the racial inequalities regarding these indicators are explained by the socioeconomic disadvantage experienced by mulattos and blacks but are also influenced by other factors, possibly by racial discrimination and/or genetics.

Operant serial feature-positive conditional discrimination with composite features and different topography responses

In a serial feature-positive conditional discrimination procedure the properties of a target stimulus A are defined by the presence or not of a feature stimulus X preceding it. In the present experiment, composite features preceded targets associated with two different topography operant responses (right and left bar pressing); matching and non-matching-to-sample arrangements were also used. Five water-deprived Wistar rats were trained in 6 different trials: X-R®Ar and X-L®Al, in which X and A were same modality visual stimuli and the reinforcement was contingent to pressing either the right (r) or left (l) bar that had the light on during the feature (matching-to-sample); Y-R®Bl and Y-L®Br, in which Y and B were same modality auditory stimuli and the reinforcement was contingent to pressing the bar that had the light off during the feature (non-matching-to-sample); A- and B- alone. After 100 training sessions, the animals were submitted to transfer tests with the targets used plus a new one (auditory click). Average percentages of stimuli with a response were measured. Acquisition occurred completely only for Y-L®Br+; however, complex associations were established along training. Transfer was not complete during the tests since concurrent effects of extinction and response generalization also occurred. Results suggest the use of both simple conditioning and configurational strategies, favoring the most recent theories of conditional discrimination learning. The implications of the use of complex arrangements for discussing these theories are considered.

Sustitución de lardo por grasa vegetal en salchichas: incorporación de pasta de aguacate. Efecto de la inhibición del oscurecimiento enzimático sobre el color

La sustitución de grasa animal es importante para mejorar la calidad nutricional de los alimentos de origen animal. Tradicionalmente, los embutidos contienen cantidades relativamente altas de grasas insaturadas, por lo que se ha buscado la sustitución parcial o total de estas con grasas o aceites de origen vegetal. El aprovechamiento del aguacate como fuente de grasa vegetal es una alternativa para este tipo de productos. La oxidación de este fruto es uno de los principales problemas durante la industrialización. En este trabajo se han añadido dos inhibidores del oscurecimiento enzimático, ácido ascórbico y eritorbato de sodio, para determinar el efecto de éstos sobre el color de salchichas de cerdo. Se han encontrado diferencias en la luminosidad de las muestras con respecto al tratamiento control, además de que este mismo parámetro se ha reducido con el tiempo de almacenamiento. No ha habido efecto significativo de los antioxidantes sobre las otras componentes del color. El uso de eritorbato de sodio en la elaboración de pasta de aguacate ha reducido el oscurecimiento de la pasta durante su congelación, sin afectar mayormente otros parámetros de color del producto terminado. La aceptación del producto por un grupo de consumidores ha sido aceptable.

The effect of irradiation and thermal process on beef heme iron concentration and color properties

The aim of this study was to evaluate the influence of irradiation and thermal process on the heme iron (heme-Fe) concentration and color properties of Brazilian cattle beef. Beef samples (patties and steaks) were irradiated at 0-10 kGy and cooked in a combination oven at 250 ºC for 9 minutes with 70% humidity. Total iron and heme iron (heme-Fe) concentrations were determined. The data were compared by multiple comparisons and fixed- effects ANOVA. Irradiation at doses higher than 5 kGy significantly altered the heme-Fe concentration. However, the sample preparation conditions interfered more in the heme-Fe content than did the irradiation. Depending on the animal species, meat heme iron levels between 35 and 52% of the total iron are used for dietetic calculations. In this study the percentage of heme-iron was, on average, 70% of the total iron showing that humidity is an important factor for its preservation. The samples were analyzed instrumentally for CIE L*, a*, and b* values.

Soy and Brazil nut beverage: processing, composition, sensory, and color evaluation

Despite its high nutritional value, soymilk consumption in Western countries is limited mainly due to undesirable flavors developed during the traditional elaboration process. Brazil nut (Bertholletia excelsa) has pleasant flavor and recognized nutritional value. Thus, the aim of this work was to elaborate a soy and Brazil nut beverage exploring the use of two national products of high nutritional quality. The process for manufacturing a soy and Brazil nut beverage consisted of elaboration, formulation, and homogenization of soymilk and Brazil nut milk. The addition of five levels (10, 20, 30, 40, and 50%) of Brazil nut milk to soy beverages was investigated. Although no significant differences in consumer average preference (p > 0.05) were observed among the beverages, analyzing both the consumer preference frequency distribution of the products and the Internal Preference Mapping (IPM), it was possible to conclude that the beverage with 30% of Brazil nut milk reached the most adequate performance demonstrating the sensory benefits Brazil nuts brought to the product. Regarding proximate composition, it did not present a better performance in terms of nutritional value, except for the oil content. The soy and Brazil nut beverage presented visual stability and no phase separation despite the non-stability shown by Brazil nut beverage itself. When Brazil nut milk was added to soy beverage, the final product became whiter than soy beverage, which is appealing to consumers who normally search for a clearer soymilk. The soy and Brazil nut beverage processing can be considered an alternative to increase the use of Brazil nuts in the Brazilian diet.