Efficient methods for acute stress detection using heart rate variability data from Ambient Assisted Living sensors

Background Using Ambient Assisted Living sensors to detect acute stress could help people mitigate the harmful effects of everyday stressful situations. This would help both the healthy and those affected more by sudden stressors, e.g., people with diabetes or heart conditions. The study aimed to develop a method for providing reliable stress detection based on heart rate variability features extracted from portable devices. Methods Features extracted from portable electrocardiogram sensor recordings were used for training various classification algorithms for stress detection purposes. Data were recorded in a clinical trial with 7 participants and two stressors, the Trier Social Stress Test and the Stroop colour word test, both validated by standardised questionnaires. Different heart rate variability feature sets (all, time-domain and non-linear only, frequency-domain only) were tested to investigate how classification performance is affected, in addition to various time window length setups and participant-wise training sessions. The accuracy and F1 score of the trained models were compared and analysed. Results The best results were achieved with models using time-domain and non-linear heart rate variability features with 5-min-long overlapping time windows, yielding 96.31% accuracy and 96.26% F1 score. Shorter overlapping windows had slightly lower performance, with 91.62–94.55% accuracy and 91.77–94.55% F1 score ranges. Non-overlapping window configurations were less effective, with both accuracy and F1 score below 88%. For participant-wise learning, average F1 scores of 99.47%, 98.93% and 96.1% were achieved for feature sets using all, time-domain and non-linear, and frequency-domain features, respectively. Conclusion The tested stress detector models based on heart rate variability data recorded by a single electrocardiogram sensor performed just as well as those published in the literature working with multiple sensors, or even better. This suggests that once portable devices such as smartwatches provide reliable hear rate variability recordings, efficient stress detection can be achieved without the need for additional physiological measurements.

L199, A NEW VARIABLE STAR IN M13

During a routine study of the variable stars of Messier 13 (NGC 6205 = Cl 1639+365) we have discovered the variability of L199 (TYC 2588-1386-2), a red giant star member of the cluster: using the photometric data –in V band– obtained in the 2019 and 2020 campaigns we have verified its variability. Data from the Zwicky Transient Facility (ZTF) and Deras et al. (2019) were utilized to determine its type of variability and period estimation: our data suggest that it is a semiregular red giant, similar to the other variables of this type of the cluster, whose cycles of photometric variation are not identical; we derived a period of ~27 days (although without a regular periodicity) and an amplitude smaller: 0.08 ± 0.03 magnitudes in V band although they may be somewhat larger or smaller. With this discovery the cluster now has 63 variable stars.

Generic Clopidogrel: Has Substitution for Brand Name Plavix® Been Effective?

Background: Following the expiration of brand name exclusivity of Plavix® in 2012, generic clopidogrel bisulfate was approved. As a widely prescribed medication with significant inter-patient pharmacokinetic and pharmacodynamic variability, data regarding the impact of switching to generic clopidogrel bisulfate on patients is needed. Objective: The objective of this study was to determine whether generic clopidogrel bisulfate is as efficacious as Plavix® for the inhibition of platelet aggregation. Methods: Patients treated with Plavix® monotherapy (n = 254) or generic clopidogrel bisulfate monotherapy (n = 185) were included in this retrospective review. Confounding factors previously found to affect clopidogrel responsiveness (diabetes, female sex, and smoking) were assessed, as well as medications classified as substrates, inducers, and inhibitors of enzymes involved in clopidogrel metabolism. Whole blood impedance aggregometry was used to measure platelet aggregation in response to adenosine diphosphate. Patients were tested after ≥2 weeks of treatment and designated as non-responders if aggregation response exceeded sensitivity thresholds of 6 ohms of impedance. Results: The introduction of generic clopidogrel bisulfate was associated with a decrease in antiplatelet resistance (44% to 31%, p < 0.01) and decreased mean ohms of resistance (5.06 ± 4.55 to 3.32 ± 4.03, p < 0.01). Prior to analysis of secondary outcomes, 217 patients were eliminated due to antiplatelet usage for longer than 3 years (n = 123 for Plavix® and n = 118 for clopidogrel). There was no statistically significant finding in prevalence of secondary events. Conclusion: Resistance rates to the antiplatelet, clopidogrel are significantly lower since the switch to generic formulations. Further investigation into the impact of variability between clopidogrel bisulfate formulations is needed.

Comparative models disentangle drivers of fruit production variability of an economically and ecologically important long-lived Amazonian tree

Trees in the upper canopy contribute disproportionately to forest ecosystem productivity. The large, canopy-emergent Bertholletia excelsa also supports a multimillion-dollar commodity crop (Brazil nut), harvested almost exclusively from Amazonian forests. B. excelsa fruit production, however is extremely variable within populations and years, destabilizing local harvester livelihoods and the extractive economy. To understand this variability, data were collected in Acre, Brazil over 10 years at two sites with similar climate and forest types, but different fruit production levels, despite their proximity (~ 30 km). One site consistently produced more fruit, showed less individual- and population-level variability, and had significantly higher soil P and K levels. The strongest predictor of fruit production was crown area. Elevation and sapwood area also significantly impacted fruit production, but effects differed by site. While number of wet days and dry season vapor pressure prior to flowering were significant production predictors, no climatic variables completely captured annual observed variation. Trees on the site with higher available P and K produced nearly three times more fruits, and appeared more resilient to prolonged drought and drier atmospheric conditions. Management activities, such as targeted fertilization, may shield income-dependent harvesters from expected climate changes and production swings, ultimately contributing to conservation of old growth forests where this species thrives.

Variability study of the FBS M giants

We study in this paper variability of the late-type M giants found in the First Byurakan Survey (FBS) spectroscopic data base. We used phase dependent light – curves from large sky area variability data bases such as Catalina Sky Survey (CSS) and All-Sky Automated Survey for Supernovae (ASAS-SN). We used also the distance information derived from Gaia EDR3 to construct the Galactic distribution of the M – type giants from the second edition of the FBS Late-Type Stars catalogue including various kinds of long period variables.

New results for FBS late-type stars using Gaia EDR3 data

We study in this paper bright late-type giants found in the First Byurakan Survey (FBS) data base. Phase dependent light-curves from large sky area variability data bases such as Catalina Sky Survey (CSS) and All-Sky Automated Survey for Supernovae (ASAS-SN), and the early installment of the third Gaia data release (Gaia EDR3) photometric and astrometric data have been used to characterize our sample of 1 100 M-type giants and 130 C-type stars found at high latitudes. Gaia radial velocities (RV) are available for 134 and luminosities for 158 stars out of 1 100. We show the behaviour of our sample stars in a Gaia color–absolute magnitude diagram (CaMD), the Gaia-2MASS-diagram from Lebzelter et al. with some alternative versions. In this way we explore the potential of these diagrams and their combination for the analysis and interpretation of datasets of LPVs. We show the possibility to classify stars into M- and C-types and to identify the mass of the bulk of the sample stars.