Correlation between menstrual cycle and cognitive performance in a chimpanzee (Pan troglodytes)

Extensive research on human subjects has tried to investigate whether there is a correlation between cognitive performance and the menstrual cycle. Less is known about the relationship between the menstrual cycle and task performance in other cognitive animals. We test whether the secretion of a sex hormone [luteinizing hormone(LH)] influences the performance of cognitive tasks by a female chimpanzee (Pan troglodytes) who is part of a long-term cognition research program. We focus on two cognitive tasks: an "easy task," which consists of simple numerical ordering, and a "difficult task," which combines numerical ordering with memorizing the numerals' spatial location. Data on the performance of these cognitive tasks, urine samples, and sexual swelling over six menstrual cycles showed that the chimpanzee's performance accuracy decreased and that the intertrial interval was longer during the LH-surge of the menstrual cycle, but only for the performance of the difficult task. These performance attributes seem to reflect a decrease in attention or motivation during ovulation. In summary, the cognitive performance of a chimpanzee was disturbed by hormonal changes despite her long-term experience in the tasks.     

Dialectical Contradictions and Classical Formal Logic

A dialectical contradiction can be appropriately described within the framework of classical formal logic. It is in harmony with the law of noncontradiction. According to our definition, two theories make up a dialectical contradiction if each of them is consistent and their union is inconsistent. It can happen that each of these two theories has an intended model. A number of examples of this are to be found in the history of science.     

Relationships Between Self-Determined Motivation and Developmental Outcomes in Sport-Based Positive Youth Development

Building on self-determination theory, this study examined the relationships between self-determined motivation toward sport participation and developmental outcomes in sport-based positive youth development. One hundred twenty participants in a sport-based positive youth development program designed to engage youth through running completed a postprogram survey measuring their self-determined motivation toward running and achievement of developmental outcomes. The results of regression analyses indicated that participants with higher self-determined motivation toward running reported higher general self-efficacy, more positive attitudes toward a healthy lifestyle, and lower engagement in threatening behavior. On the other hand, self-determined motivation was unrelated to self-reported academic performance.     

Malleable hypoeutectic Zr–Ni–Cu–Al bulk glassy alloys with tensile plastic elongation at room temperature

A new bulk glassy alloy (BGA) showing macroscopic tensile plastic elongation at room temperature has been developed in the hypoeutectic Zr–Ni–Cu–Al alloy system. The hypoeutectic Zr–Ni–Cu–Al BGA shows a high Poisson's ratio, a low Young's modulus, and is highly malleable in compression. It exhibits a Poisson's ratio of 0.39, a Young's modulus of 73 GPa, and a distinct tensile plastic elongation of about 1.7% at room temperature with necking due to the operation of many shear bands. The tensile plastic deformability seems to originate from modifications of the glass structure with increasing the number of Zr–Zr atomic pairs in the hypoeutectic composition.     

Formation of the icosahedral quasicrystalline phase in Zr70Pd30 binary glassy alloy

It is found that a single icosahedral quasicrystalline phase is formed as a primary precipitation phase in the melt-spun Zr₇₀Pd₃₀ binary glassy alloy with a two-stage crystallization process. The onset temperature of the transformation from the amorphous to the icosahedral phase is 701 K at the heating rate of 0.67 K s-1. The size of the icosahedral particles lies in the diameter range below 10 nm and the particles are distributed homogeneously. The second-stage crystallization reaction results in the formation of a Zr₂Pd phase through a single exothermic reaction. The formation of the nanoscale icosahedral phase indicates the possibility that icosahedral short-range order exists in the Zr-Pd binary glassy state. Comparison with the thermal stability of an icosahedral phase in the Zr-Ni-Pd system shows that the icosahedral phase is stabilized by the addition of Ni. The stabilization is due to the restraint of the long-range rearrangement of the constitutional elements resulting from the strong chemical affinity between Zr and Ni.     

Nanocrystallization induced by quasi-static fracture of metallic glasses at room temperature

Nanoparticles on the fracture surfaces of Co- and Fe-based metallic glasses during quasi-static compression at room temperature have been observed using a high-resolution scanning electron microscope. In terms of the differential scanning calorimeter, those nanoparticles were identified to be a result of nanocrystallization induced by the rapid fracture. Finally, the nanocrystallization behavior was evaluated by taking into account the super-high crack propagation rate and high elastic energy, which contributed to the local temperature rise up to the onset of crystallization, T _x.     

Piagetian liquid conservation in the great apes (Pan paniscus, Pan troglodytes, and Pongo pygmaeus)

An understanding of Piagetian liquid conservation was investigated in 4 bonobos (Pan paniscus), 5 chimpanzees (Pan troglodytes), and 5 orangutans (Pongo pygmaeus). The apes were tested in the ability to track the larger of 2 quantities of juice that had undergone various kinds of transformations. The accuracy of the apes' judgment depended on the shape or number of containers into which the larger quantity was transferred. The apes made their choice mainly on the basis of visual estimation but showed modest success when the quantities were occluded. The results suggest that the apes rely to a greater extent on visual information, although they might have some appreciation of the constancy of liquid quantities.     

What does an intermediate success rate mean? An analysis of a Piagetian liquid conservation task in the great apes

The study investigates what an intermediate success rate means in bonobos, chimpanzees, and orangutans. Apes participated in liquid conservation experiments where they had to track the larger of two different quantities of juice after various kinds of transformations [Suda, C., & Call, J. (2004). Piagetian liquid conservation in the great apes (Pan paniscus, Pan troglodytes, and Pongo pygmaeus). Journal of Comparative Psychology, 118, 265-279). When making a decision, apes sometimes demonstrated hesitant behavior, concurrently pointing to both alternatives or successively changing their choice. Moderately successful apes showed more hesitation than highly successful or unsuccessful apes. The results are consistent with the cognitive conflict model: The experiments created a higher degree of cognitive conflict on moderately successful apes than on very successful or unsuccessful apes. This indicates that an intermediate performance reflects the joint operation and potential conflict between two different cognitive strategies (identity and appearance) inherent to the Piagetian conservation task.