Detecting (non)parallel evolution in multidimensional spaces: angles, correlations, and eigenanalysis

Parallelism between evolutionary trajectories in a trait space is often seen as evidence for repeatability of phenotypic evolution, and angles between trajectories play a pivotal role in the analysis of parallelism. However, many biologists have been ignorant on properties of angles in multidimensional spaces, and unsound uses of angles are common in the biological literature. To remedy this situation, this study provides a brief overview on geometric and statistical aspects of angles in multidimensional spaces. Under the null hypothesis that trajectory vectors have no preferred directions, the angle between two independent vectors is concentrated around the right angle, with a more pronounced peak in a higher-dimensional space. This probability distribution is closely related to t- and beta distributions, which can be used for testing the null hypothesis concerning a pair of trajectories. A recently proposed method with eigenanalysis of a vector correlation matrix essentially boils down to the test of no correlation or concentration of multiple vectors, for which a simple test procedure is available in the statistical literature. Concentration of vectors can also be examined by tools of directional statistics such as the Rayleigh test. These frameworks provide biologists with baselines to make statistically justified inferences for (non)parallel evolution.

Application of Blue Filters Increases the Usefulness of Moreland Test in Anomaloscopic Color Vision Assessment for Blue–Green Color Range

The effect of blue light filters on the anomaloscopic examination was analyzed. Thirty subjects (18–43 y, 20 female, 10 male) without color vision disorders were examined in 4 filter conditions: no filter (F-0), Blue Control Hoya (F-BC), Med-1 JZO (F-Med1) and 450 Eschenbach (F-450). Both Rayleigh test (red–green axis) and Moreland test (blue–green axis) were performed. Application of F-BC filter shows negligible effect on color vision perception in both tests. Contrary to this, the application of strong F-450 filter causes significant shift in Moreland test towards tritanopy and the decrease in correlations of Moreland parameters with Rayleigh test parameters. The application of medium strong F-Med1 filter causes the slight shift in Moreland test towards the center of the Moreland scale and increases the Spearman correlations between Moreland and Rayleigh test parameters. This observation suggests that the about 15–40% reduction of blue diode intensity in the Moreland test may be beneficial in detecting mild changes in color vision perception in the blue-green axis and may improve its usefulness in evaluating the color vision perception disorders accompanying different illnesses, such as diabetes, glaucoma, neuritis optica, or cataract. The discussion concerning the modifications of Moreland test construction is also presented.

Seasonal Variation in Acute Dacriocystitis

Objectives: Seasonal variation is possible in some medical conditions.Acute dacryocystitis is very disturbing clinical picture and can develop in any time of the year in patients with lacrimal duct obstruction. We aimed to investigate whether there is a seasonal relationship with the emergence of acute dacryocystitis.Material and Methods:The files of the patients who applied to the ophthalmology outpatient clinic with the complaints of tearing and discharge for five years and diagnosed with acute dacryocystitis were analyzed retrospectively. Age, gender, date of occurrence of the complaints and the date of diagnosis of acute dacryocystitis were recorded. In order to determine the seasonal relationship, the data regarding the number of cases who applied every month of the year were analyzed statistically by Rayleigh test.Results: The mean age of 60 patients (45 females, 15 males) included in the study was 54.70 ± 16.80 years. It was found that all patients were not equally likely to arrive at the hospital and the onset of their complaints throughout the months of the year (p <0.05). The frequency of applications was higher between May and August.Conclusion: There seems to be a seasonal relationship with the timing of the acute dacryocystitis. In our series, more acute dacryocystitis cases were encountered in the first spring-summer months. The reason for the increase of acute dacryocystitis cases in hot seasons of the year may be due to the increase in infectious agents in these seasons.

Model selection versus traditional hypothesis testing in circular statistics: a simulation study

ABSTRACTMany studies in biology involve data measured on a circular scale. Such data require different statistical treatment from those measured on linear scales. The most common statistical exploration of circular data involves testing the null hypothesis that the data show no aggregation and are instead uniformly distributed over the whole circle. The most common means of performing this type of investigation is with a Rayleigh test. An alternative might be to compare the fit of the uniform distribution model to alternative models. Such model-fitting approaches have become a standard technique with linear data, and their greater application to circular data has been recently advocated. Here we present simulation data that demonstrate that such model-based inference can offer very similar performance to the best traditional tests, but only if adjustment is made in order to control type I error rate.

Seasonal and residential clustering at disease onset of anti-MDA5-associated interstitial lung disease

ObjectivesTo investigate whether the onset of polymyositis (PM)/dermatomyositis (DM)-associated interstitial lung disease (ILD) is influenced by season and residence in the context of myositis-specific autoantibodies.MethodsFor patients with PM/DM-associated ILD enrolled in a multicentre cohort, 365 and 481 patients were eligible for seasonal and geographical analysis, respectively, based on the availability of reliable clinical information. The patients were divided into three groups: (1) anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive patients, (2) anti-aminoacyl tRNA synthetase (anti-ARS) antibody-positive patients and (3) patients negative for those antibodies. Seasonality was assessed by the Rayleigh test. Distance from residence to the nearest waterfront was measured on Google Map and was compared between groups by the exact Wilcoxon rank-sum test.ResultsIn anti-MDA5-positive patients, the disease developed more frequently in October–March (p=0.03), whereas a seasonal relationship was not found in the remaining two patient groups. Residence at disease onset in anti-MDA5-positive patients was significantly closer to the waterfront, especially to freshwater, compared with that in anti-ARS-positive or anti-MDA5-/ARS-negative patients (p=0.003 and 0.006, respectively).ConclusionsAnti-MDA5-associated ILD occurred predominantly from October to March in individuals residing near freshwater, suggesting an environmental influence on the onset of this disease subset.

Circadian and multiday seizure periodicities, and seizure clusters in canine epilepsy

Advances in ambulatory intracranial EEG devices have enabled objective analyses of circadian and multiday seizure periodicities, and seizure clusters in humans. This study characterizes circadian and multiday seizure periodicities, and seizure clusters in dogs with naturally occurring focal epilepsy, and considers the implications of an animal model for the study of seizure risk patterns, seizure forecasting and personalized treatment protocols. In this retrospective cohort study, 16 dogs were continuously monitored with ambulatory intracranial EEG devices designed for humans. Detailed medication records were kept for all dogs. Seizure periodicity was evaluated with circular statistics methods. Circular non-uniformity was assessed for circadian, 7-day and approximately monthly periods. The Rayleigh test was used to assess statistical significance, with correction for multiple comparisons. Seizure clusters were evaluated with Fano factor (index of dispersion) measurements, and compared to a Poisson distribution. Relationships between interseizure interval (ISI) and seizure duration were evaluated. Six dogs met the inclusion criteria of having at least 30 seizures and were monitored for an average of 65 weeks. Three dogs had seizures with circadian seizure periodicity, one dog had a 7-day periodicity, and two dogs had approximately monthly periodicity. Four dogs had seizure clusters and significantly elevated Fano factor values. There were subject-specific differences in the dynamics of ISI and seizure durations, both within and between lead and clustered seizure categories. Our findings show that seizure timing in dogs with naturally occurring epilepsy is not random, and that circadian and multiday seizure periodicities, and seizure clusters are common. Circadian, 7-day, and monthly seizure periodicities occur independent of antiseizure medication dosing, and these patterns likely reflect endogenous rhythms of seizure risk.

P5474STEMI time presentation, are circadian patterns and week hours related to the outcome?

Background Previous studies have suggested that patients treated during night hours had significantly longer delay times than those treated during day hours without difference in terms of in-hospital mortality. A circadian pattern can also be seen in STEMI presentation but data analyzing a relationship between this circadian pattern and prognosis are missing. Objective We aimed to evaluate clinical outcomes of STEMI patients according to the time of medical attention (on-hour vs off-hour) and to the circadian pattern. Methods Observational, multicenter study, based on prospectively collected data from consecutive patients treated within the STEMI Network during the period between January 2010 and December 2015. On-hour presentation included patients treated between 8:00h and 19:59h on weekdays, the rest were catalogued as off-hour presentation. In the circadian pattern analysis, event frequencies were analyzed by time of onset in keeping with a circular distribution over the 24-hour clock. The Rayleigh test was used to evaluate the hypothesis of a uniform distribution of times. The primary endpoint was 1-year all-cause mortality. Secondary endpoints were 30-day all-cause mortality and in-hospital complications. Results A total of 8608 patients were included, 3795 (44.1%) in on-hour group and 4813 (55.9%) in off-hour group. There were significant differences with a shorter patient delay (157±227min vs. 141±193min; p<0.01) and longer system delay (132±86 min vs. 152±111min; p<0.01) in the on-hour vs. off-hour group. However, there was no difference in total ischemic time (287±256 min vs. 293±242 min; p=0.265). At 30-day and 1-year follow-up there were no differences in adjusted all-cause mortality between groups [OR 0.91 (CI95%: 0.73–1.12; p=0.35) and OR 0.99 (CI95%: 0.83–1.17; p=0.87), respectively]. In-hospital atrioventricular block was more frequent in on-hour group as compared to off-hour (4.2% vs 3.3%; p=0.02). A circadian pattern was observed between 9:00 am and 12:30 pm, patients presenting a circadian pattern showed a shorter patient delay (135.29±186.83min vs. 152.44±215.11min; p<0.01), system delay (134.93±89.36min vs. 145.63±104.93min; p<0.01) and total ischemic time (270.78±255.55min vs. 270.34±227.34min; p<0.01) with no differences in 30-day and 1-year mortality between patients with or without the pattern [OR 1.02 (IC95%: 0.81–1.30; p=0.85) and OR 1.12 (IC95%: 0.92 - 1.36; p=0.25) respectively]. This circadian pattern was repeated each day weekly during the period of the study. Conclusions Off-hour STEMI presentation was associated with a shorter patient delay and longer system delay without an increase in total ischemic time. The off-hour presentation was not related to an increase in 1-year all-cause mortality when compared to on-hour. A circadian pattern was found, patients included in this group presented a shorter total ischemic time without differences in 30-day and 1-year mortality.

Reproductive phenology of Ditassa burchellii (Apocynaceae, Asclepiadoideae), a herbaceous vine, in a semi-deciduous forest from Brazil

We analyzed the reproductive phenology of Ditassa burchellii and the influence of abiotic factors on the species phenophases. The study was conducted on individuals of a natural population from a semi-deciduous forest (Viçosa municipality, Minas Gerais state, southeastern Brazil). We quantified the activity and intensity indices of the following phenophases: flower bud, flower, immature fruit, and dehiscent fruit. To test for seasonality of phenophases, we analyzed each of them using Rayleigh test. We evaluated whether there was any association between abiotic variables (mean temperature, rainfall, and day length) and phenophases, in the month of occurrence and in the three months prior to the occurrence of each phenophase. The analyzed phenophases occurred mainly at the end of the rainy season and during the dry season, with overlapping periods, but with sequential peaks. The periods of occurrence of reproductive phenophases were similar to the ones in other climbing species and were mainly related to the dispersal mode. All phenophases were seasonal and were associated with at least one abiotic variable, either in the month of their occurrence or in the previous months.

Daily activity rhythm and habitat use of the semi-free European bison herd during the growing season / Denní aktivita a využití prostředí zubrem evropským (Bison bonasus) během vegetační sezóny

The European bison (Bison bonasus) became extinct in the wild in the 20th century. Due to successful reintroductions of captive individuals, the free-ranging bison population has been steadily increasing. However, the population consists of small and isolated herds whose survival depends on creating larger and connected populations. Detailed knowledge of movement and habitat use in human-dominated landscape is essential for further successful reintroductions of the European bison. Therefore, we studied daily activity and habitat use of the semi-free European bison herd in the hunting enclosure of Židlov from April to September 2014. The lead cow of the herd was fitted with a GPS collar equipped with GSM module. The average home range size of the herd was 29.5 km2 and the average daily utilisation area was 0.5 km2. Forested habitats were preferred during the day (Rayleigh test: Z = 107.31; p < 0. 0001) whereas idle lands (i.e. former shooting ranges now dominated by a mixture of pioneer tree species, hawthorn and grasslands) during the night (Rayleigh test: Z = 214.451; p < 0. 0001). The bison herd did not show any clear preference for a particular forest type (i.e. coniferous, deciduous, different age classes). Additional knowledge on year-long patterns of movement and habitat use is needed to ensure the success of reintroduction programmes