Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

One undescribed indole alkaloid together with twenty-two known compounds have been isolated from aerial parts of Vinca minor L. (Apocynaceae). The chemical structures of the isolated alkaloids were determined by a combination of MS, HRMS, 1D, and 2D NMR techniques, and by comparison with literature data. The NMR data of several alkaloids have been revised, corrected, and missing data have been supplemented. Alkaloids isolated in sufficient quantity were screened for their in vitro acetylcholinesterase (AChE; E.C. 3.1.1.7) and butyrylcholinesterase (BuChE; E.C. 3.1.1.8) inhibitory activity. Selected compounds were also evaluated for prolyl oligopeptidase (POP; E.C. 3.4.21.26), and glycogen synthase 3β-kinase (GSK-3β; E.C. 2.7.11.26) inhibition potential. Significant hBuChE inhibition activity has been shown by (−)-2-ethyl-3[2-(3-ethylpiperidinyl)-ethyl]-1H-indole with an IC50 value of 0.65 ± 0.16 μM. This compound was further studied by enzyme kinetics, along with in silico techniques, to reveal the mode of inhibition. This compound is also predicted to cross the blood-brain barrier (BBB) through passive diffusion

Risk preferences under acute stress

Many important decisions are made under stress and they often involve risky alternatives. There has been ample evidence that stress influences decision making, but still very little is known about whether individual attitudes to risk change with exposure to acute stress. To directly evaluate the causal effect of psychosocial stress on risk attitudes, we adopt an experimental approach in which we randomly expose participants to a stressor in the form of a standard laboratory stress-induction procedure: the Trier Social Stress Test for Groups. Risk preferences are elicited using a multiple price list format that has been previously shown to predict risk-oriented behavior out of the laboratory. Using three different measures (salivary cortisol levels, heart rate and multidimensional mood questionnaire scores), we show that stress was successfully induced on the treatment group. Our main result is that for men, the exposure to a stressor (intention-to-treat effect, ITT) and the exogenously induced psychosocial stress (the average treatment effect on the treated, ATT) significantly increase risk aversion when controlling for their personal characteristics. The estimated treatment difference in certainty equivalents is equivalent to 69 % (ITT) and 89 % (ATT) of the gender-difference in the control group. The effect on women goes in the same direction, but is weaker and insignificant

Foretelling what makes people pay: predicting the results of field experiments on TV fee enforcement

One of the current challenges in field experimentation is creating an efficient design including individual treatments. Ideally, a pilot should be run in advance, but when a pilot is not feasible, any information about the effectiveness of potential treatments' to researchers is highly valuable. We run a laboratory experiment in which we forecast results of two large-scale field experiments focused on TV license fee collection to evaluate the extent to which it is possible to predict field experiment results using a non-expert subject pool. Our main result is that forecasters were relatively conservative regarding the absolute effectiveness of the treatments, but in most cases they correctly predicted the relative effectiveness. Our results suggest that, despite the artificiality of laboratory environments, forecasts generated there may provide valuable estimates of the effectiveness of treatments

Carrots, Sticks, or Simplicity? Field Evidence on What Makes People Pay TV Fees

We provide evidence on both innovative as well as known behavioral strategies aimed at improving tax compliance, using a unified environment of two large correspondence experiments (N=82,599 and N=51,142) with potential TV-fees evaders in the Czech Republic. We (i) simplify the original letter and add a QR code for easier registration; use two innovative text strategies aimed at (ii) the elicitation of preference for fee designation, and (iii) the explanation of fee purpose. We also employ strategies known in the literature but providing mixed results: highlighting (iv) legal consequences of non-compliance, (v) value of services for the fee, and (vi) social norms. Apart from the text treatments, we modify the envelopes by placing there (vii) a picture of a cartoon character (supported by a sticker inside), or (viii) a red inscription “Important”, with the aim to stimulate recipients' reciprocity and attention. Our results show that the text simplification and highlighting legal consequences substantially improve effectiveness of the letter, which we self-replicate on a new sample two years later, while the remaining treatments do not improve over the baseline. The QR code brings only a modest improvement

Anti-social behavior in groups

This paper provides strong evidence supporting the long-standing speculation that decision-making in groups has a dark side, by magnifying the prevalence of anti-social behavior towards outsiders. A large-scale experiment implemented in Slovakia and Uganda (N=2,309) reveals that deciding in a group with randomly assigned peers increases the prevalence of anti-social behavior that reduces everyone’s payoff but which improves the relative position of own group. The effects are driven by the influence of a group context on individual behavior, rather than by group deliberation. The observed patterns are strikingly similar on both continents

Cephalic Secretions Of The Bumblebee Subgenus Sibiricobombus Vogt Suggest Bombus Niveatus Kriechbaumer And Bombus Vorticosus Gerstaecker Are Conspecific (Hymenoptera, Apidae, Bombus)

Three taxa of the subgenus Sibiricobombus live in the Near-East mountain steppes: Bombus niveatus, B. sulfureus and B. vorticosus. The latter is also present in the Balkan. B. niveatus and B. vorticosus can only be distinguished based on color pattern. B. sulfureus differs in coat color and in genitalia. We identified 40 compounds in the secretions of the labial glands of these taxa, among which 7 were detected for the first time in labial cephalic gland secretions of bumblebee males. Whereas the secretions of the male cephalic labial glands of B. sulfureus are very different from those of B. niveatus and B. vorticosus, we found no significant difference between the latter. We conclude that B. sulfureus is a valid species, whereas B. vorticosus is a mere subspecies of B. niveatus: Bombus niveatus ssp. vorticosus Gerstaecker nov. status.WoSScopu

Group membership magnifies the dark side of human social behavior

Does decision-making in groups foster rationality and selfishness, or does it give rise to nasty behavior towards outsiders? In this paper, we implement a large-scale lab-in-field experiment in Slovakia and Uganda (N=2,309) and provide new evidence showing that the behavioral difference in inter-personal interactions between groups and individuals is primarily driven by a stronger preference to be nasty even at one’s own expense. Furthermore, the greater nastiness of groups arises almost exclusively due to the psychological effect of being a part of a group on individual preferences, rather than due to deliberation and joint decision-making among group members. We observe strikingly similar patterns on both continents, suggesting the elevation of the dark side of human social motivations is a deeply rooted behavioral response when individuals are banded in a group. The findings have implications for economic theory and can help to explain the prevalence of self-destructive group conflicts