Cultivo de larvas de Ucides cordatus (LINNAEU, 1763) sob diferentes intensidades luminosas / Rearing of Ucides cordatus (LINNAEU, 1763) larvae under different light intensities

O caranguejo-uçá, Ucides cordatus, é uma espécie típica dos manguezais brasileiros e tem grande importância econômica para as populações litorâneas tradicionais. O presente trabalho investigou a influência da intensidade luminosa sobre a sobrevivência e a taxa de desenvolvimento larval de U. cordatus. Três intensidades luminosas foram avaliadas: claro - 710 lux, penumbra - 210 lux e escuro - 1 lux, em duas condições de cultivo, individual e coletivo. Houve diferenças significativas entre as taxas de sobrevivência das larvas zoea e as três intensidades luminosas avaliadas (p<0,05). As maiores taxas de ecdise para o estágio de megalopa foram obtidas no tratamento claro (42% nos cultivos coletivos e 30% nos cultivos individuais). No tratamento escuro, a metamorfose para megalopa foi de apenas 16% nos cultivos coletivos e de 7% nos cultivos individuais. Estes resultados indicam que a manutenção das larvas em baixas intensidades luminosas afeta negativamente a sobrevivência larval de U. cordatus...

Ucides cordatus is an edible crab species typical of Brazilian mangroves, and traditionally represents an important economic resource for many coastal populations. The present study investigated the influence of light intensity on the survival and rate of larval development of U. cordatus. Three different levels of luminosity were evaluated: 710 (Light), 210 Lux (Shaded) and 1 Lux (Dark), both in individual and collective cultivation conditions. Significant differences were found for survival of zoea larvae under the different light intensities (P<0.05). The greatest survival rates as well as rates of ecdysis to the megalopa stage were obtained under Light conditions (42% in collective cultures and 30% in individual cultures). In Dark conditions events of metamorphosis to megalopa stage was observed only in 16% of collective cultures and 7% of individual cultures. The result indicates that low light intensities may negatively affect larval survivorship during U. cordatus larval cultivations...

Effects of pleasant visual stimulation on attention, working memory, and anxiety in college students

Different emotional reactions can be induced by the presentation of visual stimuli with affective content. Emotional stimuli are processed and linked with cognitive functions, such as attention, memory, and anxiety, and have implications in the mental health field. Previous studies have reported that positive and negative emotions tend to change cognitive processes in individuals, ultimately resulting in better and worse performance, respectively. Many studies have emphasized the crucial role of affect in directing attention to relevant stimuli, enhancing learning and memory, facilitating decision making, selecting goals, and conflict resolution. The aim of the present study was to investigate the influence of pleasant visual stimuli on memory, focused attention, and anxiety and further understand the effects of emotional induction. The study investigated the effects of presenting a pleasant visual stimulus in a 1.5 min video to a sample of 145 college students on focused attention, working memory (Personnel Selection Testing, memory subtest), and anxiety (State-Trait Anxiety Inventory). Nonsignificant differences were observed in focused attention, working memory, and anxiety state. Statistically significant differences were found in trait anxiety and the comparison between men and women with regard to memory and anxiety. The positive stimulus was not sufficient to alter cognition or emotion in our research participants. Emotion was found to not be the only factor that influences memory, and other factors appear to be important, such as prior knowledge and cognitive, social, and physiological factors, including personal history, the environment, and culture...

Larviculture of two neotropical species with different distributions in the water column in light- and dark-colored tanks

The influence of tank color on the visual perception of fish larvae and the success of their cultivation depends on the characteristics of each species combined with environmental factors. In this study, we determined the effect of light and dark tank colors on the larviculture of pacamã (Lophiosilurusalexandri), a species with a benthonic habit, and curimatá-pioa (Prochilodus costatus), which swims actively in the water column. Larvae of pacamã and curimatá-pioa were cultivated for 10 days in 5-L tanks, at a density of 15 larvae L-1 and luminosity of 141.7 ± 8.95 lux, and fed Artemia nauplii. Four tank colors were used: green, light blue, brown, and black (with four replications). Survival, biomass and Fulton's condition factor for pacamã larvae were similar in the different colored tanks. However, the larvae in the green tanks showed lower weight than those cultivated in black and brown tanks, as well as shorter total length than that of larvae in the brown-colored tanks. These results are probably due to the association between tank color and benthonic habitat of the pacamã. For the curimatá-pioa, survival and biomass were similar for the different colors. The weight and Fulton's condition factor were higher for the larvae cultivated in green and blue tanks. This result could be associated with the adaptation of curimatá-pioa larvae to active swimming in the water column, searching for prey.

A interferência da cor do tanque na percepção visual da larva de peixe e no sucesso do seu cultivo depende da caraterística de cada espécie combinada com fatores ambientais. Neste estudo foi investigado o efeito de tanques de cores claras e escuras na larvicultura do pacamã Lophiosilurusalexandri, espécie de hábito bentônico, e, curimatá-pioa Prochilodus costatus, que nada ativamente na coluna da água. Larvas de pacamã e de curimatá-pioa foram cultivadas por 10 dias, em tanques contendo 5 L de água, a uma densidade de 15 larvas L-1, luminosidade de 141.7 ± 8.95 lux, alimentados com náuplios de Artemia. Quatro cores de tanques foram usadas: verde e azul claras, marrom e preta (com quatro repetições). Para as larvas de pacamã, a sobrevivência, biomassa e o fator de condição de Fulton foram similares entre os tanques de diferentes cores. Entretanto, as larvas nos tanques verdes apresentara um peso menor do que as cultivadas nos tanques de cor preta e marrom, assim como um menor comprimento total, que as larvas cultivadas em tanque marrom. Estes resultados provavelmente têm origem da associação da cor do tanque com o hábito bentônico do pacamã. Para o curimatá-pioa, a sobrevivência e a biomassa foram similares entre as cores. O peso e o fator de condição de Fulton foram maiores para as larvas cultivadas nos tanques de cor verde e azul, seguidas pelo marrom e preto. Este resultado pode estar associado a adaptação das larvas de curimatá-pioa a natação ativa na coluna da água à procura de presa.

Influence of aversive visual stimulation on attention, working memory, and anxiety in university students

The present study investigated the influence of aversive visual stimulation on anxiety, working memory, and selective attention. The study was conducted with 366 participants of both sexes, divided into three groups: (i) no visual stimuli (n = 128), (ii) neutral visual stimuli (n = 114), and (iii) aversive visual stimuli (n = 124). Two DVD films, one containing aversive stimuli and one containing neutral stimuli, were used for the respective groups. Each visual stimulation had a duration of 1 minute and 22 seconds. After viewing the DVD, anxiety, working memory, and attention were assessed. Concomitant with the increase in anxiety were deficits in working memory and deficits in selective attention in the group that was exposed to the aversive scenes. No gender differences were observed. These results suggest that aversive visual stimuli increase anxiety and decrease attention and working memory performance in university students.

Effect of visual attention on distortion product otoacoustic emissions

Effects of attention on afferent auditory information were studied by many researchers. Although researchers had used different auditory tests, yet OAEs are considered the most sensitive measurements for cochlear functions. Aim of this work was to study the effect of visual attention task on cochlear function by using DPOAEs. Eighteen normal hearing young adults were included. DPOAEs amplitude was measured in three conditions: before the visual attention task [VAT], during and after the end of the visual attention task. Statistically significant decrease in the DPOAEs amplitude during the VAT. While, there was no significant difference in DPOAEs amplitude before and after the VAT. Results of this work will help clinically in the accuracy of DPOAEs recording especially in young subjects. Moreover, this result may be also helpful in subjects with hearing loss of mild to moderate degree as their hearing level is critically detected by DPOAEs

Self induced photosensitive epilepsy.

The authors report a case of a 12-year-old girl who had rare self induced photosensitive epilepsy. She used to move her right hand over the right eye while simultaneously rubbing the forehead since the age of 8. During these episodes she was lost in herself. Lately these episodes were followed by brief spell of unconsciousness. The EEG examination, in its third attempt, revealed bilateral multiple symmetric spikes on photic stimulation. She admitted that she often induced the episode herself and derived pleasure out of it. She responded well to Sodium valproate.

Hipoclorito de sódio: análise estatística de fontes promotoras de instabilidade química / Sodium hypoclorite: statistical analysis of chemical instability promoter agents

O uso hospitalar de soluções cloradas tem sido bastante intensificada por apresentarem eficácia sobre amplo aspecto de microorganismos e serem acessíveis sob o aspecto econômico. O hipoclorito de sódio apresenta grande importância pois a partir dele são facilmente elaboradas soluções em diversas concentrações de cloro residual livre, dependendo da finalidade a que se destinam. Apresenta o incoveniente de ser instável frente a fatores extrínsecos e íntrinsecos como luz/ temperatura elevada, presença de material orgânico e pH. Este trabalho analisa o comportamento do hipoclorito de sódio (através de medida de concentração de cloro residual livre) em diferentes materiais de acondicionamento, em presença e ausência de tampa, quando submetido a níveis variáveis de luminosidade, por estes fatores serem freqüentes na rotina do trabalho diário. Empregou-se o estudo estatístico ( Modelo Split-Plot de Análise de Variância) para avaliação da significância das fontes de variação propostas e suas interações. a luminosidade e o tempo foram significativos na promoção da instabilidade química do hipoclorito de sódio

Reflex epilepsies: experience in Sri Lanka.

Reflex epilepsy (RE) is characterised by seizures that are regularly elicited by some specific stimulus or event mediated by neural pathways. In a prospective study of 1287 epileptic patients seen at Peradeniya, 223 (17.3%) were found to have RE, eating being the commonest stimulus (191 patients, 85.7%). Photosensitive epilepsy (PSE) was relatively rare. Intermittent photic stimulation on 874 unselected epileptic patients produced a positive photoconvulsive response in 60 (6.9%). None had photosensitive seizures, but 3 had a higher frequency of seizures while watching television. Eating epilepsy (EE) had the highest prevalence at Peradeniya (148/1000 epileptic patients). This group was male predominant, and the onset of epilepsy in most cases was in the second decade. The majority experienced partial complex seizures. Repetitive and chronic stimulation of the amygdala during eating is suggested as the mechanism underlying EE. Twenty-one patients had seizures evoked by calculation, problem solving or spatial tasks. Juvenile myoclonic epilepsy was the commonest form of seizure disorder in them. Although PSE itself is rare, self-induced epilepsy (SIE) was common. There were 8 patients who self-induced seizures. The majority were photosensitive and they induced seizures by gazing at the sun and waving a hand in front of the eyes. In the management of REs, clobazam produced impressive results. As for possible seizure-inhibitory mechanisms, our studies on a "Sathi" mediator showed definite EEG changes during mediation. Can mediation increase the seizure-threshold and abort or prevent the propagation of the epileptic discharge? The answer, apart from its possible therapeutic applications, may provide insight into the mechanisms of seizure generation.

Colour and photosensitive epilepsy

In this study we relate our experience in 7 cases of photosensitive epilepsy and the effect of different types of filters upon the photoconvulsive response (PR). The study was performed with an 8 channels electroencephalograph and the patients were stimulated with a Joule lamp (1 c/sec-30 c/sec). Red, yellow, blue and green cellophane paper filters were used. The EEG response presented bilateral spikes or polyspiks and slow wave paroxystic discharges. In the presence of a blue filter, the PR appeared later: an average of 6 seconds of closing the eyes and the response had a lower amplitude. In addition the PR did not appear or it was blocked when we used a double blue filter. These results support the role of the retina in the genesis of the PR. We suggest that the blue filter allows a small percentage of light transmission and under these conditions the electrical events that follow light stimulation do not occur

Epilepsia fotossensível: relato de dois casos / Photosensitive epilepsy: report of 2 cases

Epilepsia fotossensível é tema ainda pouco descrito. Os autores revisam a literatura pertinente e descrevem dois casos de epilepsia fotossensível, dando ênfase à assim chamada epilepsia da televisäo