scholarly journals Affordable and effective optokinetic response methods to assess visual acuity and contrast sensitivity in larval to juvenile zebrafish

2021 ◽  
Vol 1 ◽  
pp. 92
Author(s):  
Alicia Gómez Sánchez ◽  
Yolanda Álvarez ◽  
Basilio Colligris ◽  
Breandán N. Kennedy
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Early Morning ◽  
Time Of Day ◽  
Data Consistency ◽  
Optokinetic Response ◽  
Early Afternoon ◽  
3D Printed ◽  
Functional Vision ◽  
2D And 3D

The optokinetic response (OKR) is an effective behavioural assay to investigate functional vision in zebrafish. The rapid and widespread use of gene editing, drug screening and environmental modulation technologies has resulted in a broader need for visual neuroscience researchers to access affordable and more sensitive OKR, contrast sensitivity (CS) and visual acuity (VA) assays. Here, we demonstrate how 2D- and 3D-printed, striped patterns or drums coupled with a motorised base and microscope provide a simple, cost-effective but efficient means to assay OKR, CS and VA in larval-juvenile zebrafish. In wild-type, five days post-fertilisation (dpf) zebrafish, the 2D or 3D drums printed with the standard OKR stimulus of 0.02 cycles per degree (cpd), 100% black-white contrast evoked equivalent responses of 24.2 or 21.8 saccades per minute, respectively. Furthermore, although the OKR number was significantly reduced compared to the 0.02 cpd drum (p<0.0001), the 2D and 3D drums evoked equivalent responses with the 0.06 and 0.2 cpd drums. Notably, standard OKRs varied with time of day; peak responses of 29.8 saccades per minute occurred in the early afternoon with significantly reduced responses occurring in the early morning or late afternoon (18.5 and 18.4 saccades per minute, respectively). A customised series of 2D printed drums enabled analysis of VA and CS in 5-21 dpf zebrafish. The saccadic frequency in VA and CS assays was inversely proportional to age, spatial frequency and contrast of the stimulus. OKR, VA and CS of zebrafish larvae can be efficiently measured using 2D- or 3D-printed striped drums. For data consistency the luminance of the OKR light source, the time of day when the analysis is performed, and the order of presentation of VA and CS drums must be considered. These simple methods allow effective and more sensitive analysis of functional vision in zebrafish.

scholarly journals Affordable and Effective Optokinetic Response Methods to Assess Visual Acuity and Contrast Sensitivity in Larval to Juvenile Zebrafish

2021 ◽  
Author(s):  
Alicia Gómez Sánchez ◽  
Yolanda Álvarez ◽  
Basilio Colligris ◽  
Breandán N. Kennedy
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Early Morning ◽  
Time Of Day ◽  
Data Consistency ◽  
Optokinetic Response ◽  
Early Afternoon ◽  
3D Printed ◽  
Functional Vision ◽  
2D And 3D

AbstractBackgroundThe optokinetic response (OKR) is an effective behavioural assay to investigate functional vision in zebrafish. The rapid and widespread use of gene editing, drug screening and environmental modulation technologies have resulted in a broader need for visual neuroscience researchers to access affordable and more sensitive OKR, contrast sensitivity (CS) and visual acuity (VA) assays. Here, we demonstrate how 2D- and 3D-printed, striped patterns or drums coupled with a motorised base and microscope provide a simple, cost-effective but efficient means to assay OKR, CS and VA in larval-juvenile zebrafish.ResultsIn wild-type, 5 days post-fertilisation (dpf) zebrafish, the 2D or 3D drums printed with the standard OKR stimulus of 0.02 cycles per degree (cpd), 100% black-white contrast evoked equivalent responses of 24.2 or 21.8 saccades per minute, respectively. Furthermore, although the OKR number was significantly reduced compared to the 0.02 cpd drum (p<0.0001), the 2D and 3D drums evoked respectively equivalent responses with the 0.06 and 0.2 cpd drums. Notably, standard OKR responses varied with time of day; peak responses of 29.8 saccades per minute occurred in the early afternoon with significantly reduced responses occurring in the early morning or late afternoon, (18.5 and 18.4 saccades per minute, respectively). A customised series of 2D printed drums enabled analysis of visual acuity and contrast sensitivity in 5-21 dpf zebrafish. The saccadic frequency in visual acuity and contrast sensitivity assays, was inversely proportional to age, spatial frequency and contrast of the stimulus.ConclusionsOKR, VA and CS of zebrafish larvae can be efficiently measured using 2D- or 3D-printed striped drums. For data consistency the luminance of the OKR light source, the time of day when the analysis performed, and the order of presentation of VA and CS drums must be considered. These simple methods allow effective and more sensitive analysis of functional vision in zebrafish.

scholarly journals Affordable and effective optokinetic response methods to assess visual acuity and contrast sensitivity in larval to juvenile zebrafish

2022 ◽  
Vol 1 ◽  
pp. 92
Author(s):  
Alicia Gómez Sánchez ◽  
Yolanda Álvarez ◽  
Basilio Colligris ◽  
Breandán N. Kennedy
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Cost Effective ◽  
Early Morning ◽  
Time Of Day ◽  
Data Consistency ◽  
Optokinetic Response ◽  
Early Afternoon ◽  
3D Printed ◽  
Functional Vision

The optokinetic response (OKR) is an effective behavioural assay to investigate functional vision in zebrafish. The rapid and widespread use of gene editing, drug screening and environmental modulation technologies has resulted in a broader need for visual neuroscience researchers to access affordable and more sensitive OKR, contrast sensitivity (CS) and visual acuity (VA) assays. Here, we demonstrate how 2D- and 3D-printed, striped patterns or drums coupled with a motorised base and microscope provide a simple, cost-effective but efficient means to assay OKR, CS and VA in larval-juvenile zebrafish. In wild-type, five days post-fertilisation (dpf) zebrafish, the 2D or 3D set-ups of 0.02 cycles per degree (cpd) (standard OKR stimulus) and 100% black-white contrast evoked equivalent responses of 24.2±3.9 or 21.8±3.9 saccades per minute, respectively. Furthermore, although the OKR number was significantly reduced compared to the 0.02 cpd drum (p<0.0001), 0.06 and 0.2 cpd drums elicited equivalent responses with both set-ups. Notably, standard OKRs varied with time of day; peak responses of 29.8±7 saccades per minute occurred in the early afternoon with significantly reduced responses occurring in the early morning or late afternoon (18.5±3 and 18.4±4.5 saccades per minute, respectively). A customised series of 2D printed drums enabled analysis of VA and CS in 5-21 dpf zebrafish. The saccadic frequency in VA assays was inversely proportional to age and spatial frequency and in CS assays was inversely proportional to age and directly proportional to contrast of the stimulus. OKR, VA and CS of zebrafish larvae can be efficiently measured using 2D- or 3D-printed striped drums. For data consistency the luminance of the OKR light source, the time of day when the analysis is performed, and the order of presentation of VA and CS drums must be considered. These simple methods allow effective and more sensitive analysis of functional vision in zebrafish.

Intra- and inter-day variability in plasma tCO2 concentration in sedentary horses

2014 ◽  
Vol 10 (1) ◽  
pp. 39-47
Author(s):  
B.E. Bergstrom ◽  
J.H. Foreman ◽  
C.R. Foreman ◽  
A.M. Barger
Keyword(s):  
Blood Test ◽  
Indoor Environment ◽  
Early Morning ◽  
Time Of Day ◽  
Individual Variability ◽  
Strong Ion Difference ◽  
Serum Chemistry ◽  
Blood Samples ◽  
Early Afternoon ◽  
Glass Tubes

Sodium bicarbonate and other alkalinising solutions (‘milkshakes’) have been given to horses surreptitiously before exercise to provide exogenous buffering effects. After an initial positive blood test, some accused horse trainers claim that their horses ‘naturally test high’, so some jurisdictions allow a secured quarantine in which the horse is tested multiple times. The objective of this experiment was to determine the intra- and inter-day variability of plasma total CO2 (tCO2) and other plasma strong ions in a group of sedentary horses housed similarly to a quarantine period. The hypothesis was that plasma tCO2 would not remain constant over a multi-day monitoring interval, but would vary measurably during that interval. Eight sedentary (unconditioned) horses were studied for 2 weeks. Horses were acclimated to a climate-controlled indoor environment and an alfalfa-only diet for a minimum of 10 days prior to sampling. Horses were sampled 3 times daily for 5 consecutive days at 7:00, 11:00 and 15:00 h. Blood samples were collected directly into 10 ml heparinised evacuated glass tubes by jugular venipuncture using a double-ended 0.91 mm needle. Samples were chilled until concentrations of plasma tCO2, Na+, K+, and Cl-, were determined within 1-3 h of sampling using an automated serum chemistry analyzer which was calibrated daily using commercial reagents obtained from the manufacturer as well as externally-obtained NIST-traceable calibrating solutions. Mean results documented mild variations in mean plasma tCO2 (range 28.9-31.6 mmol/l), but individual horses’ plasma tCO2 ranged over 4-7 units. Results showed that there was considerable intra- and inter-individual variability in plasma tCO2. Mean pooled tCO2 and measured strong ion difference (SIDm) differed by time-of-day, with both late morning and early afternoon values lower than early morning values (P<0.001). There was a strong positive linear relationship between plasma SIDm and tCO2 (r=0.75, P<0.001).

EFFECT OF TIME OF DAY, A PARASITIC FUNGUS, AND A GENETIC MUTATION ON RATE OF PHOTOSYNTHESIS IN THE LOWBUSH BLUEBERRY

1966 ◽  
Vol 44 (5) ◽  
pp. 529-533 ◽  
Author(s):  
I. V. Hall ◽  
F. R. Forsyth ◽  
C. L. Lockhart ◽  
L. E. Aalders
Keyword(s):  
Early Morning ◽  
Genetic Mutation ◽  
Time Of Day ◽  
Parasitic Fungus ◽  
Mutant Type ◽  
Lowbush Blueberry ◽  
Early Afternoon ◽  
Rate Of Photosynthesis ◽  
Sugar Levels ◽  
Leaf Disks

The apparent rate of photosynthesis in the lowbush blueberry was measured, at four periods of the day, on leaf disks in Warburg flasks and with the use of Pardee's CO2 buffers. Significant differences were found in rates of O2 evolution at the four different periods. Oxygen evolution was greatest in the early morning when reducing sugars and starch levels were lowest. By early afternoon when starch and reducing sugar levels were much greater in the leaf disks the rate was the lowest.Leaf disks infected with Exobasidium vaccinii had a lower rate of apparent photosynthesis than normal leaves of the same clone. Disks cut from normal leaves of Vaccinium angustifolium had a higher rate of apparent photosynthesis than those of a variegated mutant. The leaves of the mutant were significantly smaller and seedlings of the mutant type grew more slowly than normal ones of the same cross. For these reasons lowbush blueberry plants of the mutant type or having the red-leaf disease are at a distinct disadvantage in nature.

scholarly journals Temporal and diurnal variation in social media posts to a suicide support forum

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rina Dutta ◽  
George Gkotsis ◽  
Sumithra Velupillai ◽  
Ioannis Bakolis ◽  
Robert Stewart
Keyword(s):  
At Risk ◽  
Social Media ◽  
Diurnal Variation ◽  
Suicide Attempts ◽  
Early Morning ◽  
Time Of Day ◽  
Diurnal Rhythms ◽  
Similar Time ◽  
Subsequent Decrease ◽  
Early Afternoon

Abstract Background Rates of suicide attempts and deaths are highest on Mondays and these occur more frequently in the morning or early afternoon, suggesting weekly temporal and diurnal variation in suicidal behaviour. It is unknown whether there are similar time trends on social media, of posts relevant to suicide. We aimed to determine temporal and diurnal variation in posting patterns on the Reddit forum SuicideWatch, an online community for individuals who might be at risk of, or who know someone at risk of suicide. Methods We used time series analysis to compare date and time stamps of 90,518 SuicideWatch posts from 1st December 2008 to 31st August 2015 to (i) 6,616,431 posts on the most commonly subscribed general subreddit, AskReddit and (ii) 66,934 of these AskReddit posts, which were posted by the SuicideWatch authors. Results Mondays showed the highest proportion of posts on SuicideWatch. Clear diurnal variation was observed, with a peak in the early morning (2:00–5:00 h), and a subsequent decrease to a trough in late morning/early afternoon (11:00–14:00 h). Conversely, the highest volume of posts in the control data was between 20:00–23:00 h. Conclusions Posts on SuicideWatch occurred most frequently on Mondays: the day most associated with suicide risk. The early morning peak in SuicideWatch posts precedes the time of day during which suicide attempts and deaths most commonly occur. Further research of these weekly and diurnal rhythms should help target populations with support and suicide prevention interventions when needed most.

scholarly journals Long-term Surveillance of Physical Activity Habits of Latinas Enrolled in a 12-Month Physical Activity Intervention

2016 ◽  
Vol 13 (7) ◽  
pp. 740-746 ◽  
Author(s):  
Lucas J. Carr ◽  
Shira Dunsinger ◽  
Bess H. Marcus
Keyword(s):  
Physical Activity ◽  
Physical Activity Intervention ◽  
Early Morning ◽  
Time Of Day ◽  
Daily Physical Activity ◽  
Activity Data ◽  
Late Afternoon ◽  
Long Term Study ◽  
Early Afternoon

Background:Long-term physical activity surveillance has not been conducted among Latinas. This study explored the variability of daily physical activity habits of inactive adult Latinas participating in a 12-month physical activity intervention.Methods:We collected objective physical activity data (pedometer) from 139 Spanish speaking Latinas (age = 41.6 ± 10.1 years; BMI = 29.6 ± 4.3 kg/m2) enrolled in a 12-month physical activity intervention. Total and aerobic steps (>100 steps/minute) were computed by year, season, month, day of week, time of day, and hour.Results:Participants walked an average of 6509 steps/day of which 1303 (20%) were aerobic steps. Significant physical activity differences were observed for subgroups including generational status, education, employment, income, marital status and health literacy. Significant and similar differences were observed for both total steps and aerobic steps for day of the week (weekdays > weekends) and season (summer > spring > fall > winter). Opposing trends were observed over the course of the day for total steps (early afternoon > late morning > late afternoon > early morning > evening) and aerobic steps (early morning > evening > late morning > late afternoon > early afternoon).Conclusions:Both seasonality and week day predicted physical activity habits of Latinas. This is the first long-term study to track daily physical activity habits of Latinas. These data have potential to inform the design of future physical activity interventions targeting Latinas.

Pediatric Cataract Surgery: Comparison between Ages at Surgery and Contrast Sensitivity Outcomes

2019 ◽  
Vol 43 (1) ◽  
pp. 50
Author(s):  
Aquirina Caesari Putri ◽  
Rozalina Loebis
Keyword(s):  
Visual Acuity ◽  
Cataract Surgery ◽  
Contrast Sensitivity ◽  
Cataract Extraction ◽  
Significant Negative Correlation ◽  
Natural World ◽  
P Value ◽  
Pediatric Cataract ◽  
Low Contrast ◽  
Significant Difference

Background: Pediatric cataracts are major causes of children’s blindness. Surgery has proven to be beneficial in terms of visual function prognosis. Contrast sensitivity evaluation after surgery is as important as visual acuity considering that natural world consists of various objects in low-to-medium contrasts. The purpose of this study is to analyze the difference of contrast sensitivity outcomes based on ages at surgery. Method: Retrospective data of children with pediatric developmental cataract from July 2013 to November 2015 were collected. All children who underwent cataract surgery at 60-months-old or less were randomized into two groups, ≤24 months and >24-to-60 months. Contrast sensitivity was then examined with preferential-looking method using Hiding Heidi low-contrast test face chart. The main outcome measures were contrast sensitivity of both groups. Age-at-evaluation, cataract onset, duration of follow-up, duration of deprivation and visual acuity were also noted. Result: Of 14 children (23 eyes), 11 eyes (47,8%) were in ≤24 months group, 12eyes (52,2%) were in >24-to-60 months group. All eyes underwent cataract extraction and similar type of intraocular lens implantation. Mean age-at-surgery was 28,2 months±16,8 (SD). Mean contrast sensitivity for each group was 47,50 %±42,29 and 18,33%±27,38, respectively, with p-value 0,031. Further analysis of Spearman’s correlation test demonstrated significant negative correlation (rs = -0,559; p = 0,006) between the two groups. Conclusion: There was statistically significant difference in contrast sensitivity between those who underwent surgery at ≤24 months and >24-to-60 months. Children who underwent surgery at older ages tend to have better contrast sensitivity afterwards.

Thermoregulatory responses to cold water at different times of day

1999 ◽  
Vol 87 (1) ◽  
pp. 243-246 ◽  
Author(s):  
John W. Castellani ◽  
Andrew J. Young ◽  
James E. Kain ◽  
Michael N. Sawka
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Early Morning ◽  
Cold Water Immersion ◽  
Time Of Day ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Metabolic Heat ◽  
Body Temperature Change ◽  
The Mean

This study examined how time of day affects thermoregulation during cold-water immersion (CWI). It was hypothesized that the shivering and vasoconstrictor responses to CWI would differ at 0700 vs. 1500 because of lower initial core temperatures (Tcore) at 0700. Nine men were immersed (20°C, 2 h) at 0700 and 1500 on 2 days. No differences ( P > 0.05) between times were observed for metabolic heat production (M˙, 150 W ⋅ m−2), heat flow (250 W ⋅ m−2), mean skin temperature (T sk, 21°C), and the mean body temperature-change in M˙(ΔM˙) relationship. Rectal temperature (Tre) was higher ( P < 0.05) before (Δ = 0.4°C) and throughout CWI during 1500. The change in Tre was greater ( P < 0.05) at 1500 (−1.4°C) vs. 0700 (−1.2°C), likely because of the higher Tre-T skgradient (0.3°C) at 1500. These data indicate that shivering and vasoconstriction are not affected by time of day. These observations raise the possibility that CWI may increase the risk of hypothermia in the early morning because of a lower initial Tcore.

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