#42 - Deterrence of Ants by Chemical Compounds from Six Southeastern Plants

Ant interactions with plants are diverse; therefore, one of the most important aspects of ant-plant interactions is the exposure of ants to plant compounds. These compounds can serve as cues to either enhance or deter recruitment of ants to food. The purpose of this experiment is to measure the recruitment of ants to extracts that were made from six different southeastern native plants, all of which display a wide range of chemical diversity. Seven different extracts were mixed using a sugar solution. Six of the extracts had the dried leaf material of the plants Solidago altissimus, Verbesina virginica, Callicarpa americana, Pycnanthemum muticum, Catalpa speciosa, and Cercis canadensis dissolved in the solution while the seventh was a control. The experiment was conducted for 15 minutes per solution and the number of ants was counted at each one-minute interval. Overall, the ants were attracted more towards the control extract. During the first four minutes, the mean number of ants attracted to the extracts containing Verbesina virginica and Catalpa speciosa were high, however, this number declined over time. No significant signs of recruitment were shown by the other four extracts. Collectively, the data suggests that ants were more attracted to the sugar control. This conclusion presents an application that the chemistry of plant compounds may have a strong significance to ant deterrence

Nociceptin Signals Through Calcium in \u3ci\u3eTetrahymena thermophila\u3c/i\u3e

Tetrahymena thermophila are free-living, ciliated, eukaryotic organisms that respond to stimuli by moving toward chemoattractants and avoiding chemorepellents. Chemoattractant responses involve faster ciliary beating, which propels the organisms forward more rapidly. Chemorepellents signaling involves ciliary reversal, which disrupts forward swimming, and causes the organisms to jerk back and forth, swim in small circles, or spin in an attempt to get away from the repellent. Many food sources, such as proteins, are chemoattractants for these organisms, while a variety of compounds are repellents. Repellents in nature are thought to come from the secretions of predators, or from ruptured organisms, which may serve as danger signals. Interestingly, several hormones involved in human pain signaling have been shown to be chemorepellents in Tetrahymena, including substance P, ACTH, PACAP, VIP, and nociceptin. Recently, we have been studying Tetrahymena response to nociceptin, using pharmacological inhibitors in order to elucidate components of the nociceptin signaling pathway. We have found that G-protein inhibitors and a number of mammalian tyrosine kinase inhibitors have no effect on nociceptin avoidance. However, the tyrosine kinase inhibitor, genistein, inhibits avoidance to nociceptin. Nociceptin avoidance is also inhibited by the calcium chelator, EGTA, which implicates calcium in the avoidance response. Electrophysiology studies done in a calcium-containing buffer show that 50 μM nociceptin causes a sustained depolarization of approximately 30 mV, further supporting the hypothesis that calcium is involved in nociceptin signaling. J-113397, an inhibitor of the human nociceptin receptor, also inhibits nociceptin avoidance in Tetrahymena. We are currently working to determine whether other inhibitors of the human nociceptin receptor have any effect on Tetrahymena, in order to get a more complete picture of the signaling pathway

Turbulent kinetic energy over large offshore wind farms observed and simulated by the mesoscale model WRF (3.8.1)

Wind farms affect local weather and microclimates; hence, parameterizations of their effects have been developed for numerical weather prediction models. While most wind farm parameterizations (WFPs) include drag effects of wind farms, models differ on whether or not an additional turbulent kinetic energy (TKE) source should be included in these parameterizations to simulate the impact of wind farms on the boundary layer. Therefore, we use aircraft measurements above large offshore wind farms in stable conditions to evaluate WFP choices. Of the three case studies we examine, we find the simulated ambient background flow to agree with observations of temperature stratification and winds. This agreement allows us to explore the sensitivity of simulated wind farm effects with respect to modeling choices such as whether or not to include a TKE source, horizontal resolution, vertical resolution and advection of TKE. For a stably stratified marine atmospheric boundary layer (MABL), a TKE source and a horizontal resolution on the order of 5 km or finer are necessary to represent the impact of offshore wind farms on the MABL. Additionally, TKE advection results in excessively reduced TKE over the wind farms, which in turn causes an underestimation of the wind speed deficit above the wind farm. Furthermore, using fine vertical resolution increases the agreement of the simulated wind speed with satellite observations of surface wind speed

Micrometeorological impacts of offshore wind farms as seen in observations and simulations

In Europe, offshore wind farms have a capacity of 16 GW, with 71% installed at the North Sea. These wind farms represent an additional source of turbulence and may influence the stratification of the marine boundary layer. We present aircraft measurements and simulations showing an impact on temperature and humidity at hub height in the order of 0.5 K 0.5 g kg$^{-1}$ even 60 km downwind of a wind farm cluster.We extend these simulations to explore a realistic future scenario, suggesting wakes in potential temperature and water vapor propagating more than 100 km downwind. Such impacts of wind farms are only observed in case of a strong stable stratification at rotor height, allowing wind farms to mix warmer air downward

Microtearding mode study in NSTX using machine learning enhanced reduced model

This article presents a survey of NSTX cases to study the microtearing mode (MTM) stabilities using the newly developed global reduced model for Slab-Like Microtearing modes (SLiM). A trained neutral network version of SLiM enables rapid assessment (0.05s/mode) of MTM with $98\%$ accuracy providing an opportunity for systemic equilibrium reconstructions based on the matching of experimentally observed frequency bands and SLiM prediction across a wide range of parameters. Such a method finds some success in the NSTX discharges, the frequency observed in the experiment matches with what SLiM predicted. Based on the experience with SLiM analysis, a workflow to estimate the potential MTM frequency for a quick assessment based on experimental observation has been established

Turbulent kinetic energy over large offshore wind farms observed and simulated by the mesoscale model WRF (3.8.1)

Wind farms affect local weather and microclimates; hence, parameterizations of their effects have been developed for numerical weather prediction models. While most wind farm parameterizations (WFPs) include drag effects of wind farms, models differ on whether or not an additional turbulent kinetic energy (TKE) source should be included in these parameterizations to simulate the impact of wind farms on the boundary layer. Therefore, we use aircraft measurements above large offshore wind farms in stable conditions to evaluate WFP choices. Of the three case studies we examine, we find the simulated ambient background flow to agree with observations of temperature stratification and winds. This agreement allows us to explore the sensitivity of simulated wind farm effects with respect to modeling choices such as whether or not to include a TKE source, horizontal resolution, vertical resolution and advection of TKE. For a stably stratified marine atmospheric boundary layer (MABL), a TKE source and a horizontal resolution on the order of 5&thinsp;km or finer are necessary to represent the impact of offshore wind farms on the MABL. Additionally, TKE advection results in excessively reduced TKE over the wind farms, which in turn causes an underestimation of the wind speed deficit above the wind farm. Furthermore, using fine vertical resolution increases the agreement of the simulated wind speed with satellite observations of surface wind speed. </div

Joint effect of phosphorus limitation and temperature on alkaline phosphatase activity and somatic growth in Daphnia magna

Alkaline phosphatase (AP) is a potential biomarker for phosphorus (P) limitation in zooplankton. However, knowledge about regulation of AP in this group is limited. In a laboratory acclimation experiment, we investigated changes in body AP concentration for Daphnia magna kept for 6 days at 10, 15, 20 and 25°C and fed algae with 10 different molar C:P ratios (95–660). In the same experiment, we also assessed somatic growth of the animals since phosphorus acquisition is linked to growth processes. Overall, non-linear but significant relationships of AP activity with C:P ratio were observed, but there was a stronger impact of temperature on AP activity than of P limitation. Animals from the lowest temperature treatment had higher normalized AP activity, which suggests the operation of biochemical temperature compensation mechanisms. Body AP activity increased by a factor of 1.67 for every 10°C decrease in temperature. These results demonstrate that temperature strongly influences AP expression. Therefore, using AP as a P limitation marker in zooplankton needs to consider possible confounding effects of temperature. Both temperature and diet affected somatic growth. The temperature effect on somatic growth, expressed as the Q10 value, responded non-linearly with C:P, with Q10 ranging between 1.9 for lowest food C:P ratio and 1.4 for the most P-deficient food. The significant interaction between those two variables highlights the importance of studying temperature-dependent changes of growth responses to food quality

Patterns and universals of mate poaching across 53 nations : the effects of sex, culture, and personality on romantically attracting another person’s partner

As part of the International Sexuality Description Project, 16,954 participants from 53 nations were administered an anonymous survey about experiences with romantic attraction. Mate poaching--romantically attracting someone who is already in a relationship--was most common in Southern Europe, South America, Western Europe, and Eastern Europe and was relatively infrequent in Africa, South/Southeast Asia, and East Asia. Evolutionary and social-role hypotheses received empirical support. Men were more likely than women to report having made and succumbed to short-term poaching across all regions, but differences between men and women were often smaller in more gender-egalitarian regions. People who try to steal another's mate possess similar personality traits across all regions, as do those who frequently receive and succumb to the poaching attempts by others. The authors conclude that human mate-poaching experiences are universally linked to sex, culture, and the robust influence of personal dispositions.peer-reviewe

Are men universally more dismissing than women? Gender differences in romantic attachment across 62 cultural regions

The authors thank Susan Sprecher (USA), Del Paulhus (Canada), Glenn D. Wilson (England), Qazi Rahman (England), Alois Angleitner (Germany), Angelika Hofhansl (Austria), Tamio Imagawa (Japan), Minoru Wada (Japan), Junichi Taniguchi (Japan), and Yuji Kanemasa (Japan) for helping with data collection and contributing significantly to the samples used in this study.Gender differences in the dismissing form of adult romantic attachment were investigated as part of the International Sexuality Description Project—a survey study of 17,804 people from 62 cultural regions. Contrary to research findings previously reported in Western cultures, we found that men were not significantly more dismissing than women across all cultural regions. Gender differences in dismissing romantic attachment were evident in most cultures, but were typically only small to moderate in magnitude. Looking across cultures, the degree of gender differentiation in dismissing romantic attachment was predictably associated with sociocultural indicators. Generally, these associations supported evolutionary theories of romantic attachment, with smaller gender differences evident in cultures with high–stress and high–fertility reproductive environments. Social role theories of human sexuality received less support in that more progressive sex–role ideologies and national gender equity indexes were not cross–culturally linked as expected to smaller gender differences in dismissing romantic attachment.peer-reviewe