Single pixel imaging at megahertz switching rates via cyclic Hadamard masks

Optical imaging is commonly performed with either a camera and wide-field illumination or with a single detector and a scanning collimated beam; unfortunately, these options do not exist at all wavelengths. Single-pixel imaging offers an alternative that can be performed with a single detector and wide-field illumination, potentially enabling imaging applications in which the detection and illumination technologies are immature. However, single-pixel imaging currently suffers from low imaging rates owing to its reliance on configurable spatial light modulators, generally limited to 22 kHz rates. We develop an approach for rapid single-pixel imaging which relies on cyclic patterns coded onto a spinning mask and demonstrate it for in vivo imaging of C. elegans worms. Spatial modulation rates of up to 2.4 MHz, imaging rates of up to 72 fps, and image-reconstruction times of down to 1.5 ms are reported, enabling real-time visualization of dynamic objects.

The Mansurov Effect: Real or a statistical artefact?

<p>The Mansurov Effect is related to the interplanetary magnetic field (IMF) and its ability to modulate the global electric circuit, which is further hypothesized to impact the polar troposphere through cloud generation processes. In this paper we investigate the connection between IMF By-component and polar surface pressure by using daily ERA5 reanalysis for geopotential height since 1980. Previous studies have shown to produce a significant 27-day cyclic response during solar cycle 23. However, when appropriate statistical tests are applied, the correlation is not significant at the 95% level. Our results also show that data from three other solar cycles, which have not been investigated before, produce similar cyclic responses as during solar cycle 23, but with seemingly random offset in the timing of the signal. We examine the origin of the cyclic pattern occurring in the super epoch/lead lag regression methods commonly used to support the Mansurov hypothesis in all recent papers, as well as other phenomena in this community. By generating random normally distributed noise with different levels of temporal autocorrelation, and using the real IMF By-index as forcing, we show that the methods applied to support the Mansurov hypothesis up to now, are highly susceptible, as cyclic patterns always occurs as artefacts of the methods. This, in addition to the lack of significance, suggests that there is no adequate evidence in support of the Mansurov Effect.</p>

Abstract P689: Do Cyclic Patterns of Stroke Code Activation Occur in a Comprehensive Stroke Center?

Background: The effects of circadian rhythm on stroke can include increases in morning heart rate, blood pressure, catecholamines, platelet aggregation, and hypercoagulability and might correlate with higher numbers of morning strokes. We assessed time of day and frequency of stroke code activation for a potential role of circadian rhythm in stroke risk. Methods: A retrospective analysis of prospectively collected data from an IRB approved stroke registry, from July 2004 to July 2020, was performed. Codes were included where stroke codes were activated with last known well (LKW) <6 hours to limit the effect of wake-up strokes and equalize changing practice patterns over time. Subjects were divided into four epochs based on code activation: Night (00:00-05:59), Morning (06:00-11:59), Afternoon (12:00-17:59), and Evening (18:00-23:59). Confirmed diagnosis of stroke, baseline blood pressure (SBP & DBP), heart rate (HR), and PTT were compared. Chi squared was used to compare categorical data and t test for continuous. Results: A total of 5,366 subjects were identified. Stroke code activations differed across epochs (Night n=312, 5.81%; Morning n=1439, 26.82%; Afternoon n=2207, 41.13%; Evening n=1408, 26.24%: p<0.0001). In the subset analysis of true strokes, activations also differed across epochs (Night n=125, 5.26%; Morning n= 831, 34.95%; Afternoon n=934, 39.28%; Evening n=488, 20.52%: p<0.0001). Overall, SBP was different with Evening highest and Morning lowest (x 151.6, x 148.2;p=0.01). Overall DBP showed Night highest and Afternoon lowest (x 83.9, x 81;p=0.002). Heart rate showed Night highest and Morning lowest (x 84.9, x 81.6;p=0.002). Conclusions: This study found that most stroke code activations occur in Afternoons at this CSC. This may be due to patient level characteristics, bystander availability, or other factors. Future studies should assess multi-center data and include other circadian rhythm biomarkers.

ROS and hypoxia signaling regulate periodic metabolic arousal during insect dormancy to coordinate glucose, amino acid, and lipid metabolism

Metabolic suppression is a hallmark of animal dormancy that promotes overall energy savings. Some diapausing insects and some mammalian hibernators have regular cyclic patterns of substantial metabolic depression alternating with periodic arousal where metabolic rates increase dramatically. Previous studies, largely in mammalian hibernators, have shown that periodic arousal is driven by an increase in aerobic mitochondrial metabolism and that many molecules related to energy metabolism fluctuate predictably across periodic arousal cycles. However, it is still not clear how these rapid metabolic shifts are regulated. We first found that diapausing flesh fly pupae primarily use anaerobic glycolysis during metabolic depression but engage in aerobic respiration through the tricarboxylic acid cycle during periodic arousal. Diapausing pupae also clear anaerobic by-products and regenerate many metabolic intermediates depleted in metabolic depression during arousal, consistent with patterns in mammalian hibernators. We found that decreased levels of reactive oxygen species (ROS) induced metabolic arousal and elevated ROS extended the duration of metabolic depression. Our data suggest ROS regulates the timing of metabolic arousal by changing the activity of two critical metabolic enzymes, pyruvate dehydrogenase and carnitine palmitoyltransferase I by modulating the levels of hypoxia inducible transcription factor (HIF) and phosphorylation of adenosine 5′-monophosphate-activated protein kinase (AMPK). Our study shows that ROS signaling regulates periodic arousal in our insect diapasue system, suggesting the possible importance ROS for regulating other types of of metabolic cycles in dormancy as well.

EVALUATION OF FEEDING INDICES TO ANALYSE THE FOOD PREFERENCE AND FEEDING RATE OF MACROBRACHIUM ASSAMENSE PENINSULARE (TIWARI, 1958) FROM RAWASAN STREAM OF GARHWAL, CENTRAL HIMALAYA, INDIA

In this paper the feeding index (FI), Gastro somatic index (GaSI) and Food Prevalence Index (FPI) of freshwater prawn Macrobrachium assamense peninsulare were evaluated to assess the quantity and quality of food preferred by it in the Rawasan stream. A total of 401 prawns were collected during a span of two years from five selected sites in the Rawasan stream of Garhwal in Central Himalaya, India from August 2013 to July 2015. Collected prawns were in the size range of 20-75 mm in males and 24-65 mm in females in total length. The stomach contents of 10 collected specimens were examined monthly and observed that 35% of the stomach was full or semifull and 15% stomach were empty. The highest Gastro somatic value was obtained 2.95±0.80 during June in the male and 3.25±0.44 during May in the female. After that, it gradually decreased in both the sexes and is repeated in cyclic patterns each year. More or less a similar trend was reported in the feeding index value during the study which indicates a significant relationship between feeding intensity and Gastro somatic index. The highest Food Prevalence Index (FPI) was seen as fragments of animal matter in both sexes, which was (88.48) in male and (58.26) in female prawns and the lowest FPI value was sand and debris (7.9 and 5.7) in male and female prawn respectively. The main food items were the fragment of plants as well as animals, diatoms, algae, and sand. Overall, the results show that this prawn is selectively abstemious.

Seasonal variations in pancreatic surgery outcome A retrospective time-trend analysis of 2748 Whipple procedures

Background Observing cyclic patterns in surgical outcome is a common experience. We aimed to measure this phenomenon and to hypothesize possible causes using the experience of a high-volume pancreatic surgery department. Methods Outcomes of 2748 patients who underwent a Whipple procedure at a single high-volume center from January 2000 to December 2018 were retrospectively analyzed. Three different hypotheses were tested: the effect of climate changes, the “July effect” and the effect of vacations. Results Clavien-Dindo ≥ 3 morbidity was similar during warm vs. cold months (22.5% vs. 19.8%, p = 0.104) and at the beginning of activity of new trainees vs. the rest of the year (23.5 vs. 22.5%, p = 0.757). Patients operated when a high percentage of staff is on vacation showed an increased Clavien-Dindo ≥ 3 morbidity (22.3 vs. 18.5%, p = 0.022), but similar mortality (2.3 vs. 1.8%, p = 0.553). The surgical waiting list was also significantly longer during these periods (37 vs. 27 days, p = 0.037). Being operated in such a period of the year was an independent predictor of severe morbidity (OR 1.271, CI 95% 1.086–1.638, p = 0.031). Conclusion Being operated when more staff is on vacation significantly affects severe morbidity rate. Future healthcare system policies should prevent the relative shortage of resources during these periods.

Distinct Diurnal and Day of Week Online Search Patterns Related to Common Eye Conditions

ImportanceStudies suggest diurnal patterns of some eye conditions. Leveraging new information sources such as online search data to learn more about such patterns could improve understanding of patient eye-related conditions and well-being and improve timing of clinical and remote eye care.ObjectiveTo investigate our hypothesis that the public is likely to consistently search about different eye conditions at different hours of the day or days of week, we conducted an observational study using search data for terms related to eye conditions such as conjunctivitis. We asked if search volumes reflected diurnal or day-of-week patterns and if those patterns were distinct from each other.DesignHourly search data for eye-related and control search terms for 2018 were analyzed and compared.SettingData from 10 USA states.ExposureInternet search.ParticipantsPopulations that searched Google’s search engine using our chosen study terms.Main Outcome MeasuresCyclical hourly and weekly online search patterns.ResultsDistinct diurnal (p<0.001 for all search terms) and day-of-week search patterns for eye-related terms were observed but with differing peak time periods and cyclic strengths. Some diurnal patterns represented reported clinical patterns. Of the eye related terms, “conjunctivitis” and “pink eye” had the strongest diurnal cyclic patterns based on peak-to-trough ratios. Stronger signal was restricted to and peaked in mornings, and amplitude was higher on weekdays. In contrast, “dry eyes” had a higher amplitude diurnal pattern on weekends, with stronger signal occurring over a broader evening to morning period and peaking in early morning.Conclusions and RelevanceThe frequency of online searches for various eye conditions can show cyclic patterns according to time of day or week. Further studies to understand the reasons for these variations may help supplement current clinical understanding of eye symptom presentation and improve the timeliness of patient messaging and care interventions.Key PointsQuestionDo online public search engine queries for different eye-health terms follow hourly or daily patterns and do the patterns differ from each other or reflect what is known clinically?FindingsUnique hourly and day of week eye health related search patterns appear diurnal and can reflect what has been observed clinically.MeaningOnline search data may reflect timing of eye conditions and could improve clinical understanding of eye-related symptom occurrence, including outside of clinics. Knowing precisely when patient’s eye condition interests increase holds promise -for example to optimize timing and availability of local or remote eye care resources.

Why and How to Deal With Diurnal Cyclic Patterns in Ambulatory Assessment of Emotions

The use of ambulatory assessment (AA) based methods in emotion research has steadily increased over the past decades. Although having a number of benefits over other methods, the use and analysis of AA data may pose specific challenges. Among these, the issue of dealing with diurnal cycles in emotion data has received relative scant attention. This article therefore discusses why cyclic models may be considered for analyzing AA data on emotions, and describes how this approach can be applied to an empirical AA dataset. Results suggest that cyclic modeling may be a useful method for describing and accounting for (diurnal) cyclic patterns in AA data, but should be used with a number of considerations in mind.