The relationship between pain induced autonomic arousal and perceived duration

Emotional distortions of the perceived duration of events are often explained in terms of increases and decreases in arousal. Whilst this explanation is theoretically plausible, there is a lack of evidence for a direct relationship between physiological arousal and perceived duration. The aim of the current study was to investigate whether physiological arousal, defined by autonomic nervous system (ANS) activity is directly related to perceived duration. In two experiments we measured skin conductance level (SCL) and high frequency heart rate variability (HF HRV) during verbal estimation tasks. In Experiment 1, participants estimated the duration of electro-cutaneous stimuli previously rated as inducing no pain, low pain and high pain. High intensity stimuli were perceived as lasting for longer than low intensity stimuli, and these changes in duration estimation were associated with changes in ANS activity. In Experiment 2, participants estimated the duration of a neutral visual stimulus whilst experiencing different intensities of background thermal pain (no pain, low pain, and high pain), to determine whether task-irrelevant arousal also affects time perception. Duration estimations for the neutral stimulus did not increase with pain intensity despite significant increases in SCL. Furthermore, there was no association between ANS activity and time estimation in Experiment 2. These findings suggest that the relationship between physiological arousal and time perception is more complex than previously described. Whilst physiological arousal can influence the perceived duration of events, it appears to have a greater capacity to do so when the to-be-timed stimulus is itself the source of arousal. ©American Psychological Association, 201

The southernmost beech (Fagus sylvatica) forests of Europe (Mount Etna, Italy): ecology, structural stand-type diversity and management implications

The southernmost European beech forests are located in the upper forest vegetation belt on Mount Etna volcano. Their standstructural patterns were analysed to assess the effects of the site-ecological factors and previous management practices on the forest structure. Five main structural-silvicultural types were identified among the main beech forest types: coppice, highmountain coppice (HMCo), high forest, coppice in conversion to high-forest and non-formal stand. A detailed standstructural analysis was carried out through measured dendrometric parameters and derived structural characters linked to both the horizontal and the vertical profiles. Plant regeneration processes were also assessed, and several biodiversity indicators were calculated. The collected data indicate a high variability of beech stand structures in relation to the heterogeneity of the site-ecological characteristics as well as to the effects of both natural and anthropic disturbance factors. The occurrence of particular stand structures along the altitude gradient on Mount Etna is evident. It is especially visible in the multi-stemmed HMCos in relation to the changing, and increasingly limiting, ecological factors, although at higher altitudes historical anthropic actions (felling) also have had an influence. Inside the Mediterranean area, these stands highlight their ecological marginality, in terms of both latitude and altitude, especially regarding current climate change processes

Transient stabbing headache from an acute thalamic hemorrhage

Stabbing headache can be encountered in both primary and secondary forms, but has been infrequently reported among patients with stroke, and is not known to be associated with a small well-circumscribed brain lesion. A 95-year-old woman taking warfarin presented with the sudden onset of stabbing headache strictly in the right frontal and supraorbital regions, along with gait imbalance and dysarthria. Neuroimaging revealed a small left thalamic hematoma. This association of an acute thalamic lesion with stabbing headache in the contralateral trigeminal distribution is discussed, along with a brief review of stabbing headache occurring in cerebrovascular disease

Modelo para Mensuração de Projetos de Circuitos Lógicos em Atividades Acadêmicas

Avaliando o tempo e a complexidade de circuitos, o artigo propõe uma métrica para análise de desempenho dos mesmos. O foco dessa pesquisa consiste em propor um modelo que sirva de auxílio ao aluno para concepção de um novo circuito e disponibilização de um feedback sobre a solução proposta

Measuring Multi-Joint Stiffness during Single Movements: Numerical Validation of a Novel Time-Frequency Approach

This study presents and validates a Time-Frequency technique for measuring 2-dimensional multijoint arm stiffness throughout a single planar movement as well as during static posture. It is proposed as an alternative to current regressive methods which require numerous repetitions to obtain average stiffness on a small segment of the hand trajectory. The method is based on the analysis of the reassigned spectrogram of the arm's response to impulsive perturbations and can estimate arm stiffness on a trial-by-trial basis. Analytic and empirical methods are first derived and tested through modal analysis on synthetic data. The technique's accuracy and robustness are assessed by modeling the estimation of stiffness time profiles changing at different rates and affected by different noise levels. Our method obtains results comparable with two well-known regressive techniques. We also test how the technique can identify the viscoelastic component of non-linear and higher than second order systems with a non-parametrical approach. The technique proposed here is very impervious to noise and can be used easily for both postural and movement tasks. Estimations of stiffness profiles are possible with only one perturbation, making our method a useful tool for estimating limb stiffness during motor learning and adaptation tasks, and for understanding the modulation of stiffness in individuals with neurodegenerative diseases

Spatial and temporal dispersion of Doryctobracon areolatus (Szépligeti) (Hymenoptera: Braconidae) in orchards infested with Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae).

Doryctobracon areolatus (Szépligeti) is an endoparasitoid and promising fruit fly control agent. The objective of the study was to determine the spatial (horizontal and vertical) and temporal dispersion of D. areolatus in the field. To evaluate the horizontal and temporal dispersion, two peach orchards were selected. In each orchard, 50 points were marked at different distances from the central point, from where 4,100 couples of D. areolatus were released. Four hours after release, parasitism units (PU) (3 per point) were fixed to the trees at a height of 1.5 m from the ground. The PUs were composed of ripe apples artificially infested with second instar larvae of Anastrepha fraterculus (30 larvae/fruit). For the evaluation of vertical dispersion, in an olive orchard six points were selected (trees of ≈4 m in height). Each tree was divided into three heights in relation to the ground (1.17, 2.34, and 3.51 m). Doryctobracon areolatus was able to disperse horizontally at a distance >60 m from the release point. However, the highest parasitism rates [15–45% (area 1); 15–27% (area 2)] were observed up to 25 m. Higher percentages of parasitism and of recovered offspring occur in the first days after the release of the parasitoid (2 DAR). As for vertical dispersion, D. areolatus parasitized A. fraterculus larvae up to the highest attachment height of the evaluated PUs (3.51). The results showed the potential use of D. areolatus in the management of fruit flies in the field.Online first. Accepted on 1 June 2023