In forests, the residence time of air – the inverse of first-order exchange rates – influences in-canopy chemistry and the exchanges of momentum, energy, and mass with the surrounding atmosphere. ...Accurate estimates are needed for chemical investigations of reactive trace species, such as volatile organic compounds, some of whose chemical lifetimes are on the order of average residence times. However, very few observational residence-time estimates have been reported. Little is known about even the basic statistics of real-world residence times or how they are influenced by meteorological variables such as turbulence or atmospheric stability. Here, we report opportunistic investigations of residence time of air in a free-air carbon dioxide enrichment (FACE) facility in a mature, broadleaf deciduous forest with canopy height of hc≈25 m. Using nearly 50 million FACE observations, we find that median daytime residence times in the tree crowns range from around 70 s when the trees are in leaf to just over 34 s when they are not. Residence times increase with increasing atmospheric stability, as does the spread around their central value. Residence times scale approximately with the reciprocal of the friction velocity, u∗. During some calm evenings in the growing season, we observe distinctly different behaviour: pooled air being sporadically and unpredictably vented – evidenced by sustained increases in CO2 concentration – when intermittent turbulence penetrates the canopy. In these conditions, the concept of a residence time is less clearly defined. Parameterisations available in the literature underestimate turbulent exchange in the upper half of forest crowns and overestimate the frequency of long residence times. Robust parameterisations of residence times (or, equivalently, fractions of emissions escaping the canopy) may be generated from inverse-gamma distributions, with the parameters 1.4≤α≤1.8 and β=hc/u∗ estimated from widely measured flow variables. In this case, the mean value for τ becomes formally defined as τ‾=β/(α-1). For species released in the canopy during the daytime, chemical transformations are unlikely unless the reaction timescale is on the order of a few minutes or less.
•There are some clues that antioxidants reduce the process of hemolysis.•Omega-3 fatty acids seem to be able to reduce hemolysis in sickle cell disease.•Efficacy of antioxidants in reducing hemolysis ...should be more explored.
Hemolysis is one of the main pathophysiological characteristics of sickle cell disease (SCD) and might cause or could be the result of oxidative stress. Antioxidants are studied in SCD due to their potential to ensure redox balance and minimize deleterious effects on erythrocyte membranes. The objective of this systematic review was to evaluate the efficacy of antioxidant nutrient supplementation on reducing hemolysis in SCD patients through randomized clinical trials. We conducted our study according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses and the Cochrane Handbook for Systematic Reviews of Interventions investigating whether antioxidants could improve the hemolytic status of SCD patients. This study included 587 articles published until April 2020. We reduced this pool to 12 articles by excluding duplicates, reviews, comments, and studies with non-human subjects. Omega-3 fatty acids, vitamin A, and zinc were the antioxidants that reportedly improved the indirect hemolysis parameters such as hemoglobin, hematocrit, mean corpuscular volume, or red blood cells. High-dose vitamin C and E supplementation worsened hemolysis, causing increased reticulocytes, lactate dehydrogenase, indirect bilirubin, and haptoglobin. More intervention studies especially high-quality controlled randomized clinical trials are needed to investigate the effects of antioxidant nutrients in reducing hemolysis in SCD.
•New data for choked cavitation in micro-orifices.•Cavitation number independent of pressure and velocity effects.•Cavitation number increases with micro-orifice diameter and ...thickness.•Micro-orifices less susceptible to choked cavitation than macro-orifices.
Choked cavitation was experimentally investigated with three circular micro-orifices with diameters of 150μm and 300μm and thicknesses of 1.04mm, 1.06mm and 1.93mm. Water was used as the test fluid, and experiments were carried out with upstream pressures in the range of 5.1–13.5MPa. The cavitation number at the inception and cessation of choked cavitation was found to increase with increasing the micro-orifice diameter and thickness. This suggests that micro-orifices could be characterized by very small choked cavitation numbers and therefore might be less susceptible to choking than their macro-scale counterparts. The cavitation number at the inception and cessation of choked cavitation was independent of the upstream pressure, downstream pressure, average flow velocity and orifice Reynolds number. At choking, the ratio of the upstream pressure to the downstream pressure is constant for a given micro-orifice, while during choked flow the mass flow rate through the micro-orifice is proportional to the square root of the upstream pressure.
To evaluate whether a machine learning classifier can evaluate image quality of maximum intensity projection (MIP) images from F18-FDG-PET scans. A total of 400 MIP images from F18-FDG-PET with ...simulated decreasing acquisition time (120 s, 90 s, 60 s, 30 s and 15 s per bed-position) using block sequential regularized expectation maximization (BSREM) with a beta-value of 450 and 600 were created. A machine learning classifier was fed with 283 images rated "sufficient image quality" and 117 images rated "insufficient image quality". The classification performance of the machine learning classifier was assessed by calculating sensitivity, specificity, and area under the receiver operating characteristics curve (AUC) using reader-based classification as the target. Classification performance of the machine learning classifier was AUC 0.978 for BSREM beta 450 and 0.967 for BSREM beta 600. The algorithm showed a sensitivity of 89% and 94% and a specificity of 94% and 94% for the reconstruction BSREM 450 and 600, respectively. Automated assessment of image quality from F18-FDG-PET images using a machine learning classifier provides equivalent performance to manual assessment by experienced radiologists.
Despite the fact that deficits in social communication and interaction are at the core of Autism Spectrum Conditions (ASC), no study has yet tested individuals on a continuum from neurotypical ...development to autism in an on-line, cooperative, joint action task. In our study, we aimed to assess whether the degree of autistic traits affects participants' ability to modulate their motor behavior while interacting in a Joint Grasping task and according to their given role.
Sixteen pairs of adult participants played a cooperative social interactive game in which they had to synchronize their reach-to-grasp movements. Pairs were comprised of one ASC and one neurotypical with no cognitive disability. In alternate experimental blocks, one participant knew what action to perform (instructed role) while the other had to infer it from his/her partner's action (adaptive role). When in the adaptive condition, participants were told to respond with an action that was either opposite or similar to their partner. Participants also played a non-social control game in which they had to synchronize with a non-biological stimulus.
In the social interactive task, higher degree of autistic traits predicted less ability to modulate joint action according to one's interactive role. In the non-social task, autistic traits did not predict differences in movement preparation and planning, thus ruling out the possibility that social interactive task results were due to basic motor or executive function difficulties. Furthermore, when participants played the non-social game, the higher their autistic traits, the more they were interfered by the non-biological stimulus.
Our study shows for the first time that high autistic traits predict a stereotypical interaction style when individuals are required to modulate their movements in order to coordinate with their partner according to their role in a joint action task. Specifically, the infrequent emergence of role-based motor behavior modulation during on-line motor cooperation in participants with high autistic traits sheds light on the numerous difficulties ASC have in nonverbal social interactions.
Wine lees are an under-exploited sludge-like material mainly consisting of yeast cells that, upon fermentation, settle at the bottom of wine tanks. Lees from commercial red and white winemaking were ...processed to yield mannoprotein-rich extracts. An established autoclave-based extraction protocol, as well as a simplified version of it, were applied. The composition of the obtained wine lees extracts was determined. Extracts were tested as emulsifying and foaming agents in model food systems and benchmarked against analogues extracts derived from laboratory-grown yeast cultures of the same two strains used for red and white wines production. All extracts showed good functionalities as emulsifying and foaming agents. However, some differences were noted in both composition and functionality, and these were related to the purification process used, yeast strain, and to the extract's origin (red lees, white lees, lab-grown yeasts). Extracts from real wine lees, which contained also grape-derived polyphenols, performed equally or better than the corresponding extracts derived from laboratory-grown yeast cultures of the same strains. Both red and white wine lees can be a novel and effective source of emulsifiers and foaming agents representing a valid alternative to the yeast biomass produced in bioreactors to be potentially used in the food industry.
Display omitted
•Mannoproteins-rich extracts were obtained from commercial wine lees and lab-grown yeasts.•All extracts showed good emulsifying and foaming activities in model food systems.•In emulsions, red wine lees extracts performed better than lab-grown yeast extracts.•Red and white wine lees can be considered as a novel source of food additives.•Wine lees could be exploited to improve the sustainability of the wine industry.
Human adults prefer to cooperate even when it is costly Curioni, Arianna; Voinov, Pavel; Allritz, Mathias ...
Proceedings of the Royal Society. B, Biological sciences,
04/2022, Letnik:
289, Številka:
1973
Journal Article
Recenzirano
Odprti dostop
Joint actions are cooperative activities where humans coordinate their actions to achieve individual and shared goals. While the motivation to engage in joint action is clear when a goal cannot be ...achieved by individuals alone, we asked whether humans are motivated to act together even when acting together is not necessary and implies incurring additional costs compared to individual goal achievement. Using a utility-based empirical approach, we investigated the extent of humans' preference for joint action over individual action, when the instrumental costs of performing joint actions outweigh the benefits. The results of five experiments showed that human adults have a stable preference for joint action, even if individual action is more effective to achieve a certain goal. We propose that such preferences can be understood as ascribing additional reward value to performing actions together.
We used atomistic simulations to study the origin of the change of resistance over time in the amorphous phase of GeTe, a prototypical phase-change material (PCM). Understanding the cause of ...resistance drift is one of the biggest challenges to improve multilevel storage technology. For this purpose, we generated amorphous structures via classical molecular-dynamics simulations under conditions as close as possible to the experimental operating ones of such memory devices. Moreover, we used the replica-exchange technique to generate structures comparable with those obtained in the experiment after long annealing that show an increase of resistance. This framework allowed us to overcome the main limitation of previous simulations, based on density-functional theory, that suffered from being computationally too expensive therefore limited to the nanosecond time scale. We found that resistance drift is caused by consumption of Ge atom clusters in which the coordination of at least one Ge atom differs from that of the crystalline phase and by removal of stretched bonds in the amorphous network, leading to a shift of the Fermi level towards the middle of the band gap. These results show that one route to design better memory devices based on current chalcogenide alloys is to reduce the resistance drift by increasing the rigidity of the amorphous network.
Experiences of social exclusion, including ostracism and rejection, can last anywhere from a few seconds to many years. Most research focused on short-term social exclusion, whereas virtually no ...empirical work has investigated the experiences of long-term social exclusion. Williams theorized that prolonged experiences of social exclusion (i.e., ostracism) would cause individuals to pass from the reflexive and reflective stages to the resignation stage characterized by the inability to recover threatened psychological needs and feelings of alienation, unworthiness, helplessness, and depression. Across two studies, we explored this prediction—and, in light of pain overlap theories, considered the possibility that chronic exclusion and chronic pain induce common psychological responses. Study 1 consisted of a quasi-experimental study involving five groups of participants: (1) those with chronic experiences of social exclusion (n = 82), (2) those with chronic physical pain (n = 82), (3) those with chronic hypertension (n = 69), (4) those with chronic kidney disease (n = 60), and (5) a group of healthy people (n = 83). Participants filled out a questionnaire including measures of need threat, negative emotions, and the four key outcomes linked to the resignation stage (i.e., alienation, unworthiness, helplessness, and depression). Although our data showed little evidence to support the psychological overlap between chronic exclusion and chronic physical pain, the results suggested that chronic experiences of social exclusion were associated with higher levels of negative emotions and resignation stage outcomes compared to participants in all the other groups. Furthermore, we found that threatened psychological needs mediated the effect of social exclusion on the resignation stage outcomes. Study 2 tested, but found no support for, the possibility that acute experiences of social exclusion could increase the resignation stage outcomes. Overall, our research indicates that when people are exposed to short-term exclusion, they recover their threatened psychological needs. However, when enduring chronic social exclusion, they do not, and enter the resignation stage.
PDF
