Functional infrared thermal imaging (fITI) is considered a promising method to measure emotional autonomic responses through facial cutaneous thermal variations. However, the facial thermal response ...to emotions still needs to be investigated within the framework of the dimensional approach to emotions. The main aim of this study was to assess how the facial thermal variations index the emotional arousal and valence dimensions of visual stimuli. Twenty-four participants were presented with three groups of standardized emotional pictures (unpleasant, neutral and pleasant) from the International Affective Picture System. Facial temperature was recorded at the nose tip, an important region of interest for facial thermal variations, and compared to electrodermal responses, a robust index of emotional arousal. Both types of responses were also compared to subjective ratings of pictures. An emotional arousal effect was found on the amplitude and latency of thermal responses and on the amplitude and frequency of electrodermal responses. The participants showed greater thermal and dermal responses to emotional than to neutral pictures with no difference between pleasant and unpleasant ones. Thermal responses correlated and the dermal ones tended to correlate with subjective ratings. Finally, in the emotional conditions compared to the neutral one, the frequency of simultaneous thermal and dermal responses increased while both thermal or dermal isolated responses decreased. Overall, this study brings convergent arguments to consider fITI as a promising method reflecting the arousal dimension of emotional stimulation and, consequently, as a credible alternative to the classical recording of electrodermal activity. The present research provides an original way to unveil autonomic implication in emotional processes and opens new perspectives to measure them in touchless conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Current evidence suggests that tree-fall gaps can influence forest structure and dynamics by enabling certain species guilds to persist over the long term. Here we assessed the development of local ...size hierarchies and asymmetric competition for light in tree-fall gaps, and the role played by these two processes for the persistence of rare light-demanding species in the Barro Colorado Island Forest Dynamics Plot (Panama). We performed spatial point pattern analysis, considering both the spatial locations (x,y) and the diameter at breast height (DBH) of all the woody plant recruits from the 1985 and 2000 censuses located in tree-fall gaps, and followed their fate up to the 1990–2010 and 2005–2010 censuses, respectively. For these two recruit cohorts, we found that, from the initial census until 5–10 yr later, close neighbors presented a larger DBH than the mean DBH of all individuals within gaps, which points to a positive growth response of recruits to the increased light levels in the gap centers. However, close neighbors of the 1985 cohort also showed larger than expected DBH differences that disappeared in subsequent censuses, indicating an enhancement of size differences between neighbors and the mortality of the smaller individuals. Finally, for both recruit cohorts, we found that 10–15 yr after gap formation, surviving individuals of rare light-demanding species had a negative impact on survival of neighboring individuals of other species. Our results indicate that gaps favor the persistence of rare light-demanding species through the development of local size hierarchies and asymmetric competition for light. The strength of this process, however, apparently depends upon gap size and the role played by the woody plants already existing at the time of gap formation in early colonization. Moreover, our findings suggest that in this forest, gaps may enhance colonization of plant species typical of nearby dry tropical areas, and that, over the coming decades, similar processes could strongly modify the structure and dynamics of moist tropical forests in the region.
The effective use of functional traits to explain species coexistence has been hindered by the scarce use of demographic variables, such as growth, with the association between functional traits and ...growth often assumed rather than tested. In this study, using spatial point‐pattern analyses, we spatially related three functional traits linked to plant competitive ability (maximum tree height HMAX, leaf mass per area LMA and wood density WD) to tree growth rates (basal area increment BAI10 and growth efficiency GE) in a stem‐mapped plot of a temperate rainforest in southern Chile. With this, we tested the competition‐trait similarity and the competition‐trait hierarchy hypotheses, and further assessed the relationship between functional trait values' spatial distribution and growth rate. We used spatial point‐pattern analyses, in particular, pair‐wise spatial association patterns, the Schlather's I index and mark variograms associated to specific null models to infer spatial correlations among individuals of several species with different traits and growth values. First, we found spatial similarity in trees' functional traits on a fine‐scale, a result supporting the competition‐trait hierarchy hypothesis. Second, while the HMAX and LMA specific values of the focal tree were spatially positively correlated with their neighbours' growth rates, the WD of the focal tree had a negative spatial correlation with its neighbours' growth rates. We also found a positive spatial autocorrelation among HMAX, LMA and WD at a fine‐scale; neighbouring trees tended to have similar values. In agreement with our a priori statements, we infer that HMAX and LMA provide a competitive tolerance, while WD of the focal tree has a competitive effect on its immediate neighbours. As such, we have demonstrated that functional traits mediate species interactions, which is a step forward in predictive community ecology, thus we can further our understanding regarding how traits mediate community assembly and species coexistence.
A robustifying methodology for switched systems with matched and unmatched uncertainties/perturbations and autonomous location transitions is presented. We avail of such methodology to design a ...control strategy based on integral sliding modes, thereby ensuring theoretically exact compensation of the matched uncertainties/perturbations and the minimization of the effects of the unmatched ones. An output integral sliding‐mode control technique, based on a switched algebraic hierarchical observer is also proposed. This approach allows the theoretically exact compensation of the matched uncertainties/perturbations right after the first moment. The proposed approach is illustrated via numerical simulations.
Robust generation of self-oscillation for mechanical systems in the presence of matched uncertainties/perturbations based on a two-relay controller, which naturally has a switched structure, is ...presented. Two scenarios are considered: the case when all the system states are available and the case when only output information is measured. In both scenarios, a continuous switched integral sliding modes controller is implemented to guarantee theoretically exact compensation of matched uncertainties/perturbations before the first switching. The chattering attenuation in the presence of fast parasitic dynamics can be realised by a switched gain strategy of the super-twisting algorithm. In the output-based scenario, the observer and the controller are initiated sequentially. A super twisting-based observer is used, guaranteeing theoretically exact reconstruction of the states before the controller is activated. The observer gains are also switched to diminish the chattering. Once the observer has converged, the reconstructed state is used in the controller to achieve the control objective. The observer and controller are designed to attain convergence before the first switching.
Ammonia (NH3) volatilization is the major source of nitrogen (N) loss resulting from the application of synthetic and organic N fertilizers to croplands. It is well known that in Mediterranean ...cropping systems, there is a relationship between the intrinsic characteristics of the climate and nitrous oxide (N2O) emissions, but whether the same relation exists for NH3 emissions remains uncertain. Here, we estimated the impact of edaphoclimatic conditions (including meteorological conditions after N fertilization), crop management factors, and the measurement technique on both the cumulative emissions and the NH3 emission factor (EF) in Mediterranean climate zones, drawing on a database of 234 field treatments. We used a machine learning method, random forest (RF), to predict volatilization and ranked variables based on their importance in the prediction. Random forest had a good predictive power for the NH3 EF and cumulative emissions, with an R2 of 0.69 and 0.76, respectively. Nitrogen fertilization rate (N rate) was the top-ranked predictor variable, increasing NH3 emissions substantially when N rate was higher than 170 kg N ha−1. Soil pH was the most important edaphoclimatic variable, showing greater emissions (36.7 kg NH3 ha−1, EF = 19.3%) when pH was above 8.2. Crop type, fertilizer type, and N application method also affected NH3 emission patterns, while water management, mean precipitation, and soil texture were ranked low by the model. Our results show that intrinsic Mediterranean characteristics had only an indirect effect on NH3 emissions. For instance, relatively low N fertilization rates result in small NH3 emissions in rainfed areas, which occupy a very significant surface of Mediterranean agricultural land. Overall, N fertilization management is a key driver in reducing NH3 emissions, but additional field factors should be studied in future research to establish more robust abatement strategies.
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•NH3 emissions and EF are assessed in Mediterranean climate zones after N fertilization.•Random Forest predict accurately NH3 volatilization and EF.•Nitrogen rate and soil pH are the main factors that influence NH3 emissions and EF.•N fertilization management is a key driver in reducing NH3 emissions.•Mediterranean conditions as indirect NH3 emissions drivers through the lower N rates.
Polymeric microparticles of polyethyleneglycol-polylactic acid-co-glycolic acid (PEG-PLGA) are widely used as drug carriers for a variety of applications due to their unique characteristics. Although ...existing techniques for producing polymeric drug carriers offer the possibility of achieving greater production yield across a wide range of sizes, these methods are improbable to precisely tune particle size while upholding uniformity of particle size and morphology, ensuring consistent production yield, maintaining batch-to-batch reproducibility, and improving drug loading capacity. Herein, we developed a novel scalable method for the synthesis of tunable-sized microparticles with improved monodispersity and batch-to-batch reproducibility via the coaxial flow-phase separation technique. The study evaluated the effect of various process parameters on microparticle size and polydispersity, including polymer concentration, stirring rate, surfactant concentration, and the organic/aqueous phase flow rate and volume ratio. The results demonstrated that stirring rate and polymer concentration had the most significant impact on the mean particle size and distribution, whereas surfactant concentration had the most substantial impact on the morphology of particles. In addition to synthesizing microparticles of spherical morphology yielding particle sizes in the range of 5–50 µm across different formulations, we were able to also synthesize several microparticles exhibiting different morphologies and particle concentrations as a demonstration of the tunability and scalability of this method. Notably, by adjusting key determining process parameters, it was possible to achieve microparticle sizes in a comparable range (5–7 µm) for different formulations despite varying the concentration of polymer and volume of polymer solution in the organic phase by an order of magnitude. Finally, by the incorporation of fluorescent dyes as model hydrophilic and hydrophobic drugs, we further demonstrated how polymer amount influences drug loading capacity, encapsulation efficiency, and release kinetics of these microparticles of comparable sizes. Our study provides a framework for fabricating both hydrophobic and hydrophilic drug-loaded microparticles and elucidates the interplay between fabrication parameters and the physicochemical properties of microparticles, thereby offering an itinerary for expanding the applicability of this method for producing polymeric microparticles with desirable characteristics for specific drug delivery applications.
Previous studies have suggested that empathic process involve several components such as cognitive empathy, affective empathy, and prosocial concern. It has also been reported that gender and empathy ...trait can influence empathic responses such as emotional recognition, which requires an appropriate scanning of faces. However, the degree to which these factors influence the empathic responses, which include emotion recognition, affective empathy, and cognitive empathy, has not yet been specified.
The aim of the present study was to identify the differences between individuals with high and low level of empathy trait, as well as differences between men and women, in an explicit task in order to evaluate the empathic responses.
With this goal in mind, we recorded eye movements during the presentation of dynamic emotional stimuli (joy, anger, fear, and neutral videos). After watching each video, participants had to rate the valence and arousal dimensions of emotional content and explicit empathy responses were assessed. Thirty participants (15 women) were included in a High Empathy group (HE; mean age = 21.0) and 30 participants (16 women) in the Low Empathy group (LE; mean age = 21.2), according to their scores in the Interpersonal Reactivity Index (IRI) scale.
As expected, the HE group showed higher scores than the LE group in the explicit empathy responses. These differences, based on global scores, were mainly explained by affective empathy and cognitive empathy responses but not by emotional recognition one. No differences were observed by gender in these measures. Regarding eye movements in the dynamic emotional stimuli, HE group had longer fixation duration on the eyes area than LE group. In addition, women spent more time on the eyes area in comparison to men.
Our findings suggest that both men and women with high empathy trait are more accurate to empathizing but not on the basis of the emotional recognition response. The fact that women spent more time on the eyes area did not seem to affect the empathic responses to the dynamic emotional stimulus. Overall, empathic responses of both men and women are modulated by their empathic trait. In addition, empathic trait and gender seem to impact strategies to deal with emotional facial information.
We assessed the relative importance of dispersal limitation, environmental heterogeneity and their joint effects as determinants of the spatial patterns of 229 species in the moist tropical forest of ...Barro Colorado Island (Panama). We differentiated five types of species according to their dispersal syndrome; autochorous, anemochorous, and zoochorous species with small, medium-size and large fruits. We characterized the spatial patterns of each species and we checked whether they were best fitted by Inhomogeneous Poisson (IPP), Homogeneous Poisson cluster (HPCP) and Inhomogeneous Poisson cluster processes (IPCP) by means of the Akaike Information Criterion. We also assessed the influence of species' dispersal mode in the average cluster size. We found that 63% of the species were best fitted by IPCP regardless of their dispersal syndrome, although anemochorous species were best described by HPCP. Our results indicate that spatial patterns of tree species in this forest cannot be explained only by dispersal limitation, but by the joint effects of dispersal limitation and environmental heterogeneity. The absence of relationships between dispersal mode and degree of clustering suggests that several processes modify the original spatial pattern generated by seed dispersal. These findings emphasize the importance of fitting point process models with a different biological meaning when studying the main determinants of spatial structure in plant communities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Density‐dependent mortality (DDM) is major driver of species coexistence in tropical forests. We assessed the occurrence and strength of this mechanism among saplings (i.e. trees with a diameter of ...1–4 cm) in the moist tropical forest of Barro Colorado Island (BCI), Panama, over six inter‐census periods (26 years), by using spatial point pattern analysis. We considered conspecific density‐dependent mortality, but also total DDM (i.e. the effects of conspecific and heterospecific neighbours all together) upon saplings of all species (i.e. at the community level), and on saplings of light‐demanding and shade‐tolerant ones, separately (i.e. at the light‐guild level). We also analysed the effects of conspecific DDM at the community and light‐guild levels. Conspecific density‐dependent mortality affected a lower proportion of species than was to be expected. Its strength was not significantly related with species abundance, and it had relatively weak effects at the community and light guild levels. Conversely, we detected a significant spatial signature of total DDM among all saplings, and among saplings of the light‐demanding and shade‐tolerant species, but its strength showed pronounced temporal variation. Total DDM among light‐demanding saplings was stronger than among shade‐tolerant ones and its effects were particularly marked 10–15 years after the occurrence of unusually severe droughts associated with El Niño events. Our study indicates that conspecific DDM is relatively unimportant among saplings in comparison with total DDM at community and light‐guild levels. This finding contrasts strongly with the results for seedlings, where conspecific DDM was constituted the dominant process. The pronounced temporal variations observed in the occurrence and strength of total DDM among saplings indicate that time‐varying events associated with climatic disturbances such as canopy openings or episodes of high recruit emergence might be important drivers of this process. They also emphasize the importance of considering time frames longer than one decade to study density‐dependent effects among saplings in tropical forests.
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