Branching of the Falkner-Skan solutions for λ < 0

The Falkner-Skan equation f'" + ff" + λ(1 - f'^2) = 0, f(0) = f'(0) = 0, is discussed for λ < 0. Two types of problems, one with f'(∞) = 1 and another with f'(∞) = -1, are considered. For λ = 0- a close relation between these two types is found. For λ < -1 both types of problem allow multiple solutions which may be distinguished by an integer N denoting the number of zeros of f' - 1. The numerical results indicate that the solution branches with f'(∞) = 1 and those with f'(∞) = -1 tend towards a common limit curve as N increases indefinitely. Finally a periodic solution, existing for λ < -1, is presented.

Emerging Synergisms Between Drugs and Physiologically-Patterned Weak Magnetic Fields: Implications for Neuropharmacology and the Human Population in the Twenty-First Century

Synergisms between pharmacological agents and endogenous neurotransmitters are familiar and frequent. The present review describes the experimental evidence for interactions between neuropharmacological compounds and the classes of weak magnetic fields that might be encountered in our daily environments. Whereas drugs mediate their effects through specific spatial (molecular) structures, magnetic fields mediate their effects through specific temporal patterns. Very weak (microT range) physiologically-patterned magnetic fields synergistically interact with drugs to strongly potentiate effects that have classically involved opiate, cholinergic, dopaminergic, serotonergic, and nitric oxide pathways. The combinations of the appropriately patterned magnetic fields and specific drugs can evoke changes that are several times larger than those evoked by the drugs alone. These novel synergisms provide a challenge for a future within an electromagnetic, technological world. They may also reveal fundamental, common physical mechanisms by which magnetic fields and chemical reactions affect the organism from the level of fundamental particles to the entire living system

Triplet Exciton Generation in Bulk-Heterojunction Solar Cells based on Endohedral Fullerenes

Organic bulk-heterojunctions (BHJ) and solar cells containing the trimetallic nitride endohedral fullerene 1-[3-(2-ethyl)hexoxy carbonyl]propyl-1-phenyl-Lu3N@C80 (Lu3N@C80-PCBEH) show an open circuit voltage (VOC) 0.3 V higher than similar devices with [6,6]-phenyl-C[61]-butyric acid methyl ester (PC61BM). To fully exploit the potential of this acceptor molecule with respect to the power conversion efficiency (PCE) of solar cells, the short circuit current (JSC) should be improved to become competitive with the state of the art solar cells. Here, we address factors influencing the JSC in blends containing the high voltage absorber Lu3N@C80-PCBEH in view of both photogeneration but also transport and extraction of charge carriers. We apply optical, charge carrier extraction, morphology, and spin-sensitive techniques. In blends containing Lu3N@C80-PCBEH, we found 2 times weaker photoluminescence quenching, remainders of interchain excitons, and, most remarkably, triplet excitons formed on the polymer chain, which were absent in the reference P3HT:PC61BM blends. We show that electron back transfer to the triplet state along with the lower exciton dissociation yield due to intramolecular charge transfer in Lu3N@C80-PCBEH are responsible for the reduced photocurrent

Corrigendum: Editorial: Sex and gender effects on power, status, dominance, and leadership – an interdisciplinary look at human and other mammalian societies

In the published article, there was an error in Research investigating sex effects in non-human mammals, paragraph 5. We omitted a few words in two places of the same sentence. The sentence previously stated: “Several papers in this Research Topic investigated whether the degree of dominance of females over males depends on morphological, demographic or ecological factors such as relative body size, adult sex ratio, sexual maturity or mating season.” The corrected sentence appears below: “Several papers in this Research Topic investigated whether the degree of dominance of females over males depends on morphological, demographic, ecological or social factors such as relative body size, adult sex ratio, sexual maturity, mating season or social support.” In the published article, there was an error in Research investigating sex effects in non-human mammals, paragraph 7. We omitted a full sentence citing the results of one study of the Research Topic. This sentence previously stated: “Conversely, Koenig et al. show in wild gray langurs that male dominance appears inflexible across contexts, and that the rare events of female aggression toward males are aimed at infant protection, while most male aggression towards females occur in a feeding context. This work suggests that intersexual feeding competition may contribute to shaping male-female relationships.” The corrected sentence appears below: “Conversely, Koenig et al. show in wild gray langurs that male dominance appears inflexible across contexts, and that the rare events of female aggression toward males are aimed at infant protection, while most male aggression towards females occur in a feeding context. This work suggests that intersexual feeding competition may contribute to shaping male-female relationships. Moreover, McCormick et al. report support for the idea that sex differences in agonistic behavior as well as in social support both mediate female dominance over males in clans of spotted hyenas, even though adult females can often dominate immigrant males without any support.” In the published article, there was an error in Research investigating sex effects in non-human mammals, paragraph 8. A couple of words need to be changed to the following sentence to avoid repeats arising from the inserted sentence. This sentence previously stated: “Finally, in the female-dominated society of spotted hyenas, East et. al., show that male fitness is substantially affected by the loss of offspring due to infanticide by females.” The corrected sentence appears below: “Finally, also in spotted hyenas, East et al. show that male fitness is substantially affected by the loss of offspring due to infanticide by females.” The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.</p

Editorial: Sex and gender effects on power, status, dominance, and leadership – an interdisciplinary look at human and other mammalian societies

In human societies, men tend to have more power, status, dominance, and occupy leadership positions more often than women; similarly, in animal societies, power and dominance are often unequally distributed between males and females. Despite these similarities across societies of humans and animals, the scientific study of power, status, dominance, and leadership have (for the most part) progressed in isolation, with little cross-disciplinary exchange or fertilization between the natural and social sciences

Direct and crossed effects of somatosensory electrical stimulation on motor learning and neuronal plasticity in humans

Purpose Sensory input can modify voluntary motor function. We examined whether somatosensory electrical stimulation (SES) added to motor practice (MP) could augment motor learning, interlimb transfer, and whether physiological changes in neuronal excitability underlie these changes. Methods Participants (18-30 years, n = 31) received MP, SES, MP + SES, or a control intervention. Visuomotor practice included 300 trials for 25 min with the right-dominant wrist and SES consisted of weak electrical stimulation of the radial and median nerves above the elbow. Single-and double-pulse transcranial magnetic stimulation (TMS) metrics were measured in the intervention and nonintervention extensor carpi radialis. Results There was 27 % motor learning and 9 % (both p <0.001) interlimb transfer in all groups but SES added to MP did not augment learning and transfer. Corticospinal excitability increased after MP and SES when measured at rest but it increased after MP and decreased after SES when measured during contraction. No changes occurred in intra-cortical inhibition and facilitation. MP did not affect the TMS metrics in the transfer hand. In contrast, corticospinal excitability strongly increased after SES with MP + SES showing sharply opposite of these effects. Conclusion Motor practice and SES each can produce motor learning and interlimb transfer and are likely to be mediated by different mechanisms. The results provide insight into the physiological mechanisms underlying the effects of MP and SES on motor learning and cortical plasticity and show that these mechanisms are likely to be different for the trained and stimulated motor cortex and the non-trained and non-stimulated motor cortex