EFFECT OF DIFFERENT LIGHTING CONDITIONS ON FEEDING ACTIVITY AND EYE ADAPTATION OF POST LARVAE PENAEUS VANNAMEI

2015 ◽  
Vol 77 (33) ◽  
Author(s):  
Noorsyarinah Sanudin ◽  
Audrey Daning Tuzan ◽  
Gunzo Kawamura ◽  
Annita Seok Kian Yong
Keyword(s):  
Feeding Activity ◽  
Light Condition ◽  
Larval Feeding ◽  
Penaeus Vannamei ◽  
Dark Condition ◽  
Clear Zone ◽  
Lighting Conditions ◽  
Pigment Granules ◽  
Screening Pigment ◽  
Dark Conditions

This study was conducted to investigate the effect of light and dark conditions on feeding activity and eye adaptations of post larvae (PL5, PL10, PL20 and PL30) Penaeus vannamei fed with frozen Artemia. Shrimp PL were placed individually in beakers and after acclimatization under the light or dark condition, PL were left to ingest known number of Artemia for 30 minutes. Thereafter, each PL was subsequently anesthetized by putting an ice cube into the beakers followed by adding few drops of paraformaldehyde. The results showed that the PL5 ingested significantly more frozen Artemia under light condition compared to dark condition (P<0.05). The eye structures of PL5 comprises of crystalline cone, rhabdom and fasciculated zone. However, it was incomplete due to the lack of clear zone and no migration of the screening pigment granules was observed under light and dark conditions. On the contrary, the number of frozen Artemia ingested by the latter stages PL10, PL20 and PL30 showed no significant differences (P>0.05) under both light conditions and these PL have complete eye structures with define clear zone. The width of clear zone was found to increase proportionally with the growth of the PL. Besides that, the screening pigment granules were able to migrate under light and dark conditions. The ability of the PL10, PL20 and PL30 to ingest almost similar numbers of Artemia under light and dark conditions suggests that different lighting conditions did not affect the feeding activity of the PL and other sensory organs may play roles in detecting food, while PL5 need light to improve their feeding activity. Based on these results, we suggest that in aquaculture practice, during the rearing of early stage of PL (<PL5), a brighter environment or light should be provided to enhance larval feeding activities. Whereas, later stages of PL (>PL10) can be cultured under any light condition.

scholarly journals Effect of noisy galvanic vestibular stimulation on dynamic posture sway under visual deprivation in patients with bilateral vestibular hypofunction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Po-Yin Chen ◽  
Ying-Chun Jheng ◽  
Chien-Chih Wang ◽  
Shih-En Huang ◽  
Ting-Hua Yang ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Light Exposure ◽  
Light Condition ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Lateral Deviation ◽  
Clinical Trial Registration ◽  
Vestibular Hypofunction ◽  
Dark Conditions ◽  
Bilateral Vestibular Hypofunction

AbstractA single-blind study to investigate the effects of noisy galvanic vestibular stimulation (nGVS) in straight walking and 2 Hz head yaw walking for healthy and bilateral vestibular hypofunction (BVH) participants in light and dark conditions. The optimal stimulation intensity for each participant was determined by calculating standing stability on a force plate while randomly applying six graded nGVS intensities (0–1000 µA). The chest–pelvic (C/P) ratio and lateral deviation of the center of mass (COM) were measured by motion capture during straight and 2 Hz head yaw walking in light and dark conditions. Participants were blinded to nGVS served randomly and imperceivably. Ten BVH patients and 16 healthy participants completed all trials. In the light condition, the COM lateral deviation significantly decreased only in straight walking (p = 0.037) with nGVS for the BVH. In the dark condition, both healthy (p = 0.026) and BVH (p = 0.017) exhibited decreased lateral deviation during nGVS. The C/P ratio decreased significantly in BVH for 2 Hz head yaw walking with nGVS (p = 0.005) in light conditions. This study demonstrated that nGVS effectively reduced walking deviations, especially in visual deprived condition for the BVH. Applying nGVS with different head rotation frequencies and light exposure levels may accelerate the rehabilitation process for patients with BVH.Clinical Trial Registration This clinical trial was prospectively registered at www.clinicaltrials.gov with the Unique identifier: NCT03554941. Date of registration: (13/06/2018).

scholarly journals Are Microplastics Impairing Marine Fish Larviculture?—Preliminary Results with Argyrosomus regius

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 104
Author(s):  
Diana Campos ◽  
Andreia C. M. Rodrigues ◽  
Rui J. M. Rocha ◽  
Roberto Martins ◽  
Ana Candeias-Mendes ◽  
...  
Keyword(s):  
Oxidative Damage ◽  
Fish Larvae ◽  
Feeding Activity ◽  
Early Ontogeny ◽  
Antioxidant Defenses ◽  
Nutritional Requirements ◽  
Larval Feeding ◽  
Argyrosomus Regius ◽  
And Performance ◽  
Aquaculture Facilities

The presence of small-sized (<300 µm) microplastics (MPs) in aquaculture facilities may threaten finfish hatchery, as their (in)voluntary ingestion by fish larvae may compromise nutritional requirements during early ontogeny, and consequently larval health and performance. Thus, we addressed the short-term effects (7 h) of polyethylene microplastics (0.1, 1.0, 10 mg/L, PE-MPs) in meagre larvae Argyrosomus regius (15 dph) in the presence/absence of food. Larval feeding behavior, oxidative stress status, neurotoxicity, and metabolic requirements were evaluated. Results showed that meagre larvae ingested PE-MPs regardless of their concentration, decreasing in the presence of food (Artemia metanauplii). The presence of PE-MPs compromised larval feeding activity at the highest concentration. Under starvation, exposed larvae activated the antioxidant defenses by increasing the total glutathione levels and inhibiting catalase activity, which seemed efficient to prevent oxidative damage. Such larvae also presented increased energy consumption potentially related to oxidative damage prevention and decreased neurotransmission. Biochemical responses of fed larvae showed a similar trend, except for LPO, which remained unaffected, except at 0.1 mg/PE-MPs/L. Our results suggest that small-sized MPs in finfish hatcheries may compromise larvae nutritional requirements, but at considerably higher levels than those reported in marine environments. Nevertheless, cumulative adverse effects due to lower MPs concentrations may occur.

Diurnal changes in retinula cell sensitivities and receptive fields (two-dimensional angular sensitivity functions) in the apposition eyes of Ligia exotica (Crustacea, Isopoda)

2001 ◽  
Vol 204 (2) ◽  
pp. 239-248 ◽  
Author(s):  
T. Hariyama ◽  
V.B. Meyer-Rochow ◽  
T. Kawauchi ◽  
Y. Takaku ◽  
Y. Tsukahara
Keyword(s):  
Receptive Fields ◽  
Resolving Power ◽  
Pigment Cells ◽  
Diurnal Changes ◽  
Two Dimensional ◽  
Angular Sensitivity ◽  
Pigment Granules ◽  
Screening Pigment ◽  
The Difference ◽  
Night And Day

The structural organization of the retinula cells in the eye of Ligia exotica changes diurnally. At night, the microvilli elongate, losing the regular and parallel alignment characteristic of the day condition. Crystalline cones and distal rhabdom tips are not pushed into each other during the day, but at night the rhabdoms protrude into the crystalline cones by up to 5 microm. Screening pigment granules in the retinula cells disperse during the night, but migrate radially towards the vicinity of the rhabdom during the day. No such displacements of the pigment granules of either distal or proximal screening pigment cells were observed. The sensitivity of the eye, monitored by electroretinogram (ERG) recordings, changes diurnally: values at midnight are, on average, 10 times those occurring during the day. However, intracellular recordings from single retinula cells (50 during the day and 50 at night) indicate that the difference between night and day sensitivities is only 2.5-fold. Two-dimensional angular sensitivity curves, indicative of a single unit's spatial sensitivity, had considerably less regular outlines at night than during the day. If based on the 50 % sensitivity level, day and night eyes possessed receptive fields of almost identical width (approximately 2 degrees), but if sensitivities below the 50 % limit were included, then receptive fields at night were significantly more extensive. We suggest that the morphological adaptations and diurnal changes in chromophore content seen in the apposition eye of L. exotica allow this animal to improve its photon capture at night while preserving at least some of the spatial resolving power characteristic of the light-adapted state. This would explain why this animal is capable of performing complex escape behaviours in the presence of predators both in bright and in very dim light.

scholarly journals Effect of LED Lighting Illuminance and Correlated Color Temperature on Working Memory

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Chung Won Lee ◽  
Jin Ho Kim
Keyword(s):  
Working Memory ◽  
Standard Deviation ◽  
Repeated Measures ◽  
Memory Performance ◽  
Light Condition ◽  
Bright Light ◽  
Color Temperature ◽  
Led Lighting ◽  
Temperature Conditions ◽  
Lighting Conditions

This study was conducted to verify how the illuminance and correlated color temperature of LED lighting affect working memory. For this study, an automatic LED lighting device based on a light sensor was developed and used, and the lighting conditions were treated with a total of six conditions (2 × 3): two illuminance conditions (dim: 400 lx, bright: 1,000 lx) and three correlated color temperature conditions (3,000 K, 5,000 K, and 7,000 K). There were 30 participants in the study, and the average age was 21.6 years (Standard deviation = 1.92). Participants were assigned to all six lighting conditions, and the placement order was randomized. For the measurement of working memory, 3-back task was used and the correct responses for 5 minutes were used as a dependent variable. As a result of repeated measures analysis of variance (ANOVA), both illuminance and correlated color temperature were found to be significant variables affecting working memory, and no interaction effect between illuminance and correlated color temperature was found. As a result of the post hoc verification conducted thereafter, the working memory performance in the bright light condition (1,000 lx) was 48.32 (Standard deviation = 15.63) on average, compared to 44.80 (Standard deviation = 15.29) in the relatively dim condition (400 lx). It was found that the condition of bright light was superior in performing working memory compared to relatively dim condition. The working memory performance in the correlated color temperature condition (5,000 K) was 48.32 (Standard deviation = 16.41) on average and higher than that of other color temperature conditions. As a result, working memory performance was the best in 1,000 lx, 5,000 K condition Mean = 53.43 (Standard deviation = 18.38), and 400 lx, 7,000 K condition Mean = 42.73 (Standard deviation = 17.68) showed the worst performance of working memory.

scholarly journals Locomotor and feeding activity rhythms in a light-entrained diurnal rodent, Octodon degus

1999 ◽  
Vol 277 (2) ◽  
pp. R523-R531 ◽  
Author(s):  
R. García-Allegue ◽  
P. Lax ◽  
A. M. Madariaga ◽  
J. A. Madrid
Keyword(s):  
Wheel Running ◽  
Feeding Strategy ◽  
Feeding Activity ◽  
Masking Effect ◽  
Constant Darkness ◽  
Octodon Degus ◽  
Lighting Conditions ◽  
Anticipatory Activity ◽  
Skeleton Photoperiod ◽  
Two Peaks

The wheel running (WR) and feeding activity (FA) of Octodon degus, a new laboratory rodent characterized by its diurnal habits, were recorded under different lighting conditions. Under 12:12-h light-dark (LD 12:12) cycles, WR activity exhibited a crepuscular pattern with two peaks, M and E, associated with “dawn” and “dusk,” respectively. In both cases, an anticipatory activity was patent, suggesting that, beside the masking effect of LD transitions, both peaks have an endogenous origin. This pattern, which was also observed under a skeleton photoperiod (LD 0.5:11.5), became unimodal after LD 0.5:23.5 and constant darkness (DD) exposure. Simultaneously, FA showed an arrhythmic pattern in most animals, especially under DD, when none of the animals exhibited a significant circadian rhythm. The existence of two groups of oscillators, or two oscillators, would explain most properties of the WR rhythms noted in this species. Our results show that the degu’s temporal feeding strategy seems mainly arrhythmic, whereas its WR pattern is driven by a strongly circadian bimodal rhythm.

scholarly journals Spatial resolution of unmanned aerial vehicles acquired imagery as a result of different processing conditions

2021 ◽  
Vol 67 (3) ◽  
pp. 148-154
Author(s):  
Jaroslav Kubišta ◽  
Peter Surový
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Spatial Resolution ◽  
Light Condition ◽  
Weather Conditions ◽  
Flight Speed ◽  
Lighting Conditions ◽  
Aerial Vehicles ◽  
Flight Height ◽  
The Impact ◽  
Imagery Data

Abstract Increasing availability of Unmanned aerial vehicles (UAV) and different software for processing of UAV imagery data brings new possibilities for on-demand monitoring of environment, making it accessible to broader spectra of professionals with variable expertise in image processing and analysis. This brings also new questions related to imagery quality standards. One of important characteristics of imagery is its spatial resolution as it directly impacts the results of object recognition and further imagery processing. This study aims at identifying relationship between spatial resolution of UAV acquired imagery and variables of imagery acquiring conditions, especially UAV flight height, flight speed and lighting conditions. All of these characteristics has been proved as significantly influencing spatial resolution quality and all subsequent data based on this imagery. Higher flight height as well as flight speed brings lower spatial resolution, whereas better lighting conditions lead to better spatial resolution of imagery. In this article we conducted a study testing various heights, flight speeds and light conditions and tested the impact of these parameters on Ground Resolved Distance (GRD). We proved that from among the variables, height is the most significant factor, second position is speed and finally the light condition. All of these factors could be relevant for instance in implementation of UAV in forestry sector, where imagery data must be often collected in diverse terrain conditions and/or complex stand (especially vertical) structure, as well as different weather conditions.

scholarly journals Germination responses of seeds of Desmodium triflorum

2018 ◽  
Vol 4 (2) ◽  
pp. 19 ◽  
Author(s):  
Niroj Paudel ◽  
Prakash Deep Rai
Keyword(s):  
Seed Germination ◽  
Blue Light ◽  
White Light ◽  
Red Light ◽  
Light Condition ◽  
Dark Condition ◽  
Percentage Germination ◽  
Negative Effect

<p class="abstract"><strong>Background:</strong> Germination of <em>Desmodium triflorum</em> is used for the scarification using the acid is valuable for the different light condition.</p><p class="abstract"><strong>Methods:</strong> The sample was collected as four month of interval of time and the seed is treated with acids with different time.  </p><p class="abstract"><strong>Results:</strong> seeds scarified with sulfuric acids for 10 min before sowing had better germination than those scarified for 5 and 15 min. Among them light qualities, red and white light had slightly promoted effect whereas blue light and dark condition had slightly negative effect on seed germination.</p><p><strong>Conclusions:</strong> In comparison to blue light and dark condition, red light and white light were promoted to percentage germination indicating the role of phytochrome in seed germination of <em>Desmodium triflorum</em>. </p>

scholarly journals Optical Quality after Posterior Chamber Phakic Implantation of an Intraocular Lens with a Central Hole (V4c Implantable Collamer Lens) under Different Lighting Conditions

2019 ◽  
Author(s):  
Tianrui He ◽  
Yi Zhu ◽  
Jibo Zhou
Keyword(s):  
Intraocular Lens ◽  
High Myopia ◽  
Optical Quality ◽  
Central Hole ◽  
Posterior Chamber ◽  
Optical Parameters ◽  
Implantable Collamer Lens ◽  
Lighting Conditions ◽  
Significant Difference ◽  
Dark Conditions

Abstract Background The current study compared optical quality before and after implantation of a posterior chamber phakic intraocular lens with a central hole [V4c implantable collamer lens (ICL)] under bright and dark lighting conditions by means of the Optical Quality Analysis System™ (OQAS; Visiometrics, Terrassa, Spain). Methods This prospective study involved 91 eyes of 46 consecutive patients undergoing implantation of a V4c ICL (15 males and 31 females). The modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and predicted visual acuities (PVAs; 100%, 20%, and 9%), under different lighting conditions, were measured before and 1 week, 1 month, and 3 months after surgery. Results All optical parameters showed significant improvements, at all time points, under dark condition after surgery. We observed no significant changes in PVA 9% at 1 week (P=0.12) or 1 month after surgery (P=0.08) under light condition; but all other postoperative parameters improved significantly. Comparing the two lighting conditions, the OSI decreased more under dark conditions at 1 week (P=0.02), 1 month (P=0.004), and 3 months (P=0.002), but there was no significant difference in any other parameter. In addition, patients were divided into a high myopia group (group H) and a super-high myopia group (group S), the group S improved significantly more than group H in all parameters, under both bright and dark conditions. Conclusions V4c ICL implantation improved optical quality under both bright and dark lighting conditions, and had a better ability to reduce the extent of scattering in the dark. Furthermore, group S achieved greater improvement in visual quality, which should be considered by physicians before surgery.

scholarly journals Optical Quality after Posterior Chamber Phakic Implantation of an Intraocular Lens with a Central Hole (V4c Implantable Collamer Lens) under Different Lighting Conditions

2020 ◽  
Author(s):  
Tianrui He ◽  
Yi Zhu ◽  
Jibo Zhou
Keyword(s):  
Intraocular Lens ◽  
High Myopia ◽  
Mean Value ◽  
Optical Quality ◽  
Central Hole ◽  
Posterior Chamber ◽  
Spherical Equivalent ◽  
Implantable Collamer Lens ◽  
Lighting Conditions ◽  
Dark Conditions

Abstract Background: The current study compared optical quality before and after implantation of a posterior chamber phakic intraocular lens with a central hole [V4c implantable collamer lens (ICL)] under bright and dark lighting conditions by means of the Optical Quality Analysis System™ (OQAS; Visiometrics, Terrassa, Spain). Methods: This prospective study involved 91 eyes of 46 consecutive high myopia patients (15 males and 31 females, average spherical equivalent -10.50±0.33D) undergoing implantation of a V4c ICL. The modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and predicted visual acuities (PVAs; 100%, 20%, and 9%), under different lighting conditions, were measured before and 1 week, 1 month, and 3 months after surgery. Results: All optical parameters showed significant improvements, at all time points, under dark condition after surgery. We observed no significant changes in PVA 9% at 1 week (mean value 0.539, P=0.12) or 1 month after surgery (mean value 0.573, P=0.08) under bright condition; but all other postoperative parameters improved significantly. Comparing the two lighting conditions, the OSI decreased more under dark conditions at 1 week (P=0.02), 1 month (P=0.004), and 3 months (P=0.002), but there was no significant difference in any other parameter. In addition, patients were divided into super high myopia (group S, spherical equivalent greater than -10 D) and high myopia (group H, spherical equivalent from -6 D to -10 D), the group S improved significantly more than group H in all parameters, under both bright and dark conditions. Conclusions: V4c ICL implantation improved optical quality under both bright and dark lighting conditions, and had a better ability to reduce the extent of scattering in the dark. Furthermore, group S achieved greater improvement in visual quality, which should be considered by physicians before surgery.

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