Predator gaze captures both human and chimpanzee attention.

Primates can rapidly detect potential predators and modify their behavior based on the level of risk. The gaze direction of predators is one feature that primates can use to assess risk levels: recognition of a predator's direct stare indicates to prey that it has been detected and the level of risk is relatively high. Predation has likely shaped visual attention in primates to quickly assess the level of risk but we know little about the constellation of low-level (e.

African jewel fish (Hemichromis bimaculatus) distinguish individual faces based on their unique iridophore patterns.

Previous research has shown that African jewel fish (Hemichromis bimaculatus) recognize pair-bonded mates during their exchanges of egg-guarding duties. The current research examined the perceptual cues for face recognition by comparing two face models displaying anatomically realistic arrangements of blue iridophores derived from discriminant function analysis of distinct sibling groups. Four groups each consisting of 9 subadults were examined using a narrow compartment restraining lateral movement where face models were presented at eye level for eight trials.

The Saliency of Snake Scales and Leopard Rosettes to Infants: Its Relevance to Graphical Patterns Portrayed in Prehistoric Art.

Geometrically arranged spots and crosshatched incised lines are frequently portrayed in prehistoric cave and mobiliary art. Two experiments examined the saliency of snake scales and leopard rosettes to infants that are perceptually analogous to these patterns. Experiment 1 examined the investigative behavior of 23 infants at three daycare facilities.

Effects of biaxial strain on the impurity-induced magnetism in P-doped graphene and N-doped silicene: a first principles study.

The effects of biaxial strain on the impurity-induced magnetism in P-doped graphene (P-graphene) and N-doped silicene (N-silicene) are studied by means of spin-polarized density functional calculations, using the supercell approach. The calculations were performed for three different supercell sizes 4 × 4, 5 × 5, and 6 × 6, in order to simulate three different dopant concentrations 3.1, 2.

Development of snake-directed antipredator behavior by wild white-faced capuchin monkeys: III. the signaling properties of alarm-call tonality.

In many primates, the acoustic properties of alarm calls can provide information on the level of perceived predatory threat as well as influence the antipredator behavior of nearby conspecifics. The present study examined the harmonics-to-noise ratio (tonality of spectral structure) of alarm calls emitted by white-faced capuchin monkeys (Cebus capucinus) in trees directed at photographic models of a boa constrictor, neotropical rattlesnake, scorpion eater snake, and white snake-shaped control presented on the ground. The average and peak harmonics-to-noise ratios of initial alarm calls by infants, juveniles, and adults and those of nearby second callers were analyzed using PRAAT software.

Forward-facing predators attract attention in humans (Homo sapiens).

Even prey that successfully evade attack incur costs when responding to predators. These nonlethal costs can impact their reproductive success and survival. One strategy that prey can use to minimize these costs is to adjust their antipredator behavior based on the perceived level of risk.

Hydrogen storage in bimetallic Ti-Al sub-nanoclusters supported on graphene.

Recent studies suggest that graphene decorated with light metal atoms is a feasible alternative for the design of the next generation of hydrogen storage systems, that is, materials which require a gravimetric content of at least 7.5 wt%, and an adsorption energy of 0.2-0.

Evolutionary constraints on equid domestication: Comparison of flight initiation distances of wild horses (Equus caballus ferus) and plains zebras (Equus quagga).

Habituation to humans was an essential component of horse (Equus caballus ferus) domestication, with the nondomestication of zebras (Equus quagga) possibly reflecting an adaptive constraint on habituation. We present the human hunting hypothesis, arguing that ancestral humans hunted African animals, including zebras, long enough to promote a persistent wariness of humans, whereas a briefer period of hunting horses in Central Asia influenced by glacial cycles was unlikely to produce an equally persistent wariness. An alternative habituation to humans hypothesis, prompted by field observations, posits that zebras can habituate well to nonthreatening humans given sufficient exposure.

Isolation rearing reveals latent antisnake behavior in California ground squirrels (Otospermophilus becheeyi) searching for predatory threats.

This study of California ground squirrels (Otospermophilus beecheyi) investigated the long-term effects of isolation rearing on alarm-call recognition. Six wild-caught squirrels, trapped as yearlings, and six laboratory-reared squirrels were maintained in solitary cages for approximately 3 years prior to the study. Visual searching and olfactory searching were measured as squirrels emerged from their burrow-like nest box into a laboratory room after hearing repetitive playbacks of alarm calls or control sounds consisting of pulses of white-noise or ambient laboratory sounds.

Dangerous animals capture and maintain attention in humans.

Predation is a major source of natural selection on primates and may have shaped attentional processes that allow primates to rapidly detect dangerous animals. Because ancestral humans were subjected to predation, a process that continues at very low frequencies, we examined the visual processes by which men and women detect dangerous animals (snakes and lions). We recorded the eye movements of participants as they detected images of a dangerous animal (target) among arrays of nondangerous animals (distractors) as well as detected images of a nondangerous animal (target) among arrays of dangerous animals (distractors).

Pressure effects on the electronic structure and superconducting critical temperature of Li2B2.

We present the structural, electronic and superconducting properties of Li2B2 under pressure within the framework of the density functional theory. The structural parameters, electronic band structure, phonon frequency of the E2g phonon mode and superconducting critical temperature Tc were calculated for pressures up to 20 GPa. We predicted that the superconducting critical temperature of Li2B2 is about 11 K and this decreases as pressure increases.

Thermal sensitisation by lonidamine of human melanoma cells grown at low extracellular pH.

Purpose: This study tested the ability of lonidamine (LND), a clinically applicable inhibitor of monocarboxylate transporters (MCT), to thermally sensitise human melanoma cells cultured at a tumour-like extracellular pH (pHe) 6.7.

Materials And Methods: Human melanoma DB-1 cells cultured at pHe 6.

Wild Asian elephants distinguish aggressive tiger and leopard growls according to perceived danger.

Prey species exhibit antipredator behaviours such as alertness, aggression and flight, among others, in response to predators. The nature of this response is variable, with animals reacting more strongly in situations of increased vulnerability. Our research described here is the first formal study to investigate night-time antipredator behaviour in any species of elephants, Asian or African.

Re-examination of the C(6)Li(6) structure: to be, or not to be symmetric.

The potential energy surface of C6 Li6 was re-examined and a new non-symmetric global minimum was found. The new structure can be described as three C2 (2-) fragments strongly aggregated through lithium bridges. At high temperatures, fluxionality is perceived instead of dissociation.

A comparison of rural and urban Indian children's visual detection of threatening and nonthreatening animals.

Recent studies indicate that young children preferentially attend to snakes, spiders, and lions compared with nondangerous species, but these results have yet to be replicated in populations that actually experience dangerous animals in nature. This multi-site study investigated the visual-detection biases of southern Indian children towards two potentially dangerous taxa, snakes and lions, that constituted major threats during human evolution. Three- to 8-year-old children from two distinct populations were presented with visual-search tasks containing one target image embedded in matrices of eight distractor images.

Development of snake-directed antipredator behavior by wild white-faced capuchin monkeys: II. Influence of the social environment.

Young animals are known to direct alarm calls at a wider range of animals than adults. If social cues are safer and/or more reliable to use than asocial cues for learning about predators, then it is expected that the development of this behavior will be affected by the social environment. Our study examined the influence of the social environment on antipredator behavior in infant, juvenile, and adult wild white-faced capuchin monkeys (Cebus capucinus) at Lomas Barbudal Biological Reserve in Costa Rica during presentations of different species of model snakes and novel models.

Development of snake-directed antipredator behavior by wild white-faced capuchin monkeys: I. Snake-species discrimination.

Young animals are known to direct alarm calls at a wider range of species than adults. Our field study examined age-related differences in the snake-directed antipredator behavior of infant, juvenile, and adult white-faced capuchin monkeys (Cebus capucinus) in terms of alarm calling, looking behavior, and aggressive behavior. In the first experiment, we exposed infant and juvenile white-faced capuchins to realistic-looking inflatable models of their two snake predators, the boa constrictior (Boa constrictor) and neotropical rattlesnake (Crotalus durissus) and a white airplane as a novel control.

Rapid detection of visually provocative animals by preschool children and adults.

The ability to detect dangerous animals rapidly in complex landscapes has been historically important during human evolution. Previous research has shown that snake images are more readily detected than images of benign animals. To provide a stringent test of superior snake detection in preschool children and adults, Experiment 1 consisted of two parts using a touch-screen visual search task.

Effects of Co doping on the metamagnetic states of the ferromagnetic fcc Fe-Co alloy.

The evolution of the metamagnetic states in the ferromagnetic face centered cubic (fcc) Fe(1-x)Co(x) alloy as a function of Co concentration has been studied by means of first-principles calculations. The ground state properties were obtained using the full-potential linear augmented plane wave method and the generalized gradient approximation for the exchange-correlation functional. The alloying was modeled using the virtual crystal approximation and the magnetic states were obtained from the calculations of the total energy as a function of the spin moment, using the fixed spin moment method.

Rock squirrel (Spermophilus variegatus) blood sera affects proteolytic and hemolytic activities of rattlesnake venoms.

Rock squirrels (Spermophilus variegatus) from two sites in south central New Mexico, where prairie (Crotalus viridis viridis) and western diamondback (Crotalus atrox) rattlesnakes are common predators, were assayed for inhibition of rattlesnake venom digestive and hemostatic activities. At statistically significant levels rock squirrel blood sera reduced the metalloprotease and hemolytic activity of venoms from C. v.

Pseudoreplication conventions are testable hypotheses.

Hurlbert's conceptions of pseudoreplication, such as the loss of independent replicates with repeated sampling over time and the lack of appropriate spatial interspersion of experimental units to achieve statistical independence, are really theoretical hypotheses that warrant empirical confirmation or disconfirmation. Schank and Koehnle have provided a valuable service to researchers in ecology, conservation biology, and animal behavior using logical argument and repeated Monte Carlo simulations to challenge Hurlbert's theoretical assumptions about statistical independence. Their simulations showed that averaging samples to produce a single datum destroys the information within experimental units and is mathematically equivalent to the treatment level in a nested analysis of variance.

Relaxed selection in the wild.

Natural populations often experience the weakening or removal of a source of selection that had been important in the maintenance of one or more traits. Here we refer to these situations as 'relaxed selection,' and review recent studies that explore the effects of such changes on traits in their ecological contexts. In a few systems, such as the loss of armor in stickleback, the genetic, developmental and ecological bases of trait evolution are being discovered.

Phase-pure TiO(2) nanoparticles: anatase, brookite and rutile.

We report on the synthesis of phase-pure TiO(2) nanoparticles in anatase, rutile and brookite structures, using amorphous titania as a common starting material. Phase formation was achieved by hydrothermal treatment at elevated temperatures with the appropriate reactants. Anatase nanoparticles were obtained using acetic acid, while phase-pure rutile and brookite nanoparticles were obtained with hydrochloric acid at a different concentration.

Orbital frontal cortex ablations of rock squirrels (Spermophilus variegatus) disinhibit innate antisnake behavior.

The antisnake behavior of rock squirrels (Spermophilus variegatus) was examined to determine the role of the orbital frontal cortex in regulating physiological arousal and behavioral excitability during encounters with a rattlesnake predator. Rock squirrels with orbital frontal cortex ablations and sham-surgery control squirrels were presented with a caged rattlesnake pre- and postsurgery. Orbital frontal cortex ablations had no substantial effect on the expression of gross motor behavior in dealing with the rattlesnake, but they augmented the speed of snake recognition and clearly disinhibited sympathetic arousal as manifested by increased tail piloerection and tail-flagging activity, which is a specific antisnake behavior.

The re-emergence of felid camouflage with the decay of predator recognition in deer under relaxed selection.

When a previously common predator disappears owing to local extinction, the strong source of natural selection on prey to visually recognize that predator becomes relaxed. At present, we do not know the extent to which recognition of a specific predator is generalized to similar looking predators or how a specific predator-recognition cue, such as coat pattern, degrades under prolonged relaxed selection. Using predator models, we show that deer exhibit a more rapid and stronger antipredator response to their current predator, the puma, than to a leopard displaying primitive rosettes similar to a locally extinct predator, an early jaguar.