Effects of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance: comparison of horizontal and 6 degrees head-down bed rest

This study examined the effect of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance. Each of 7 volunteers were maintained for 3 days of head-down and horizontal bed rest in a counter-balanced design. Assessment measures were polysomnographic recordings on the first night and performance on psychophysiological tasks on the second day involving subjective and objective vigilance, P300, simple reaction time tasks, and dual performance tasks. No clear difference in sleep structure was observed between the head-down and horizontal conditions, except for a slight decrease in Stage 4 for head-down. Both subjective and objective daytime vigilance, P300, and the simple RT task showed no statistical difference, although tracking performance on the dual task showed deterioration at 10:00 for the head-down condition. These results suggest that nocturnal sleep, daytime vigilance, and psychophysiological functions were not disturbed in head-down sleep conditions, although there was a mild deterioration of higher attentional function in the morning.     

Limbic networks and associative learning: II. Entorhinal contributions to spontaneous alternation, passive avoidance, and taste aversion learning

The hippocampus plays an important role in learning and memory, but the precise nature of that involvement remains uncertain. Transection of the perforant path, a primary input pathway to the hippocampus, has been shown to produce changes in reaction to novelty and acquisition of active avoidance; the nature and magnitude of these changes vary with lateral or medial perforant path damage. In a series of experiments on adult rats, the role of these pathways in spontaneous alternation, exploration, acquisition and extinction of conditioned responses, passive avoidance, and conditioned taste aversion was investigated. Lateral transection reduced exploration while medial transection facilitated acquisition of an active avoidance response; no effects were observed on any other measure. Results are discussed in terms of what perforant path damage might reveal regarding the interactions of the hippocampus with other brain regions.     

Local chemistry of a nanocrystalline high-strength Mg 97 Y 2 Zn 1 alloy

The local chemistry of a high-strength nanocrystalline Mg 97 Y 2 Zn 1 alloy produced by a rapidly solidified powder metallurgy process has been characterized by a three-dimensional atom probe (3DAP). The consolidated and extruded rod consists of hcp Mg grains of approximately 150nm size with their basal planes normal to the radial direction of the rod. 3DAP results revealed that the Y and Zn contents vary depending on the grains. Y- and Zn-depleted grains have a hcp structure, while Y- and Zn-enriched grains have a unique long-period stacking of the basal plane designated as 6H-Mg. In the 6H-Mg phase, the enrichment of Y and Zn occurs in one or two atomic layers in the unit cell. The chemical composition of the solute-enriched layer was estimated to be approximately 10 at.% Y and 3 at.% Zn using the 3DAP.     

Highly inhomogeneous compressive plasticity in nanocrystal-toughened Zr–Cu–Ni–Al bulk metallic glass

A Zr₆₂Cu_15.5Al₁₀Ni_12.5 bulk metallic glass with a large supercooled liquid region of 90 K, produced by copper-mould casting, exhibits a high strength of 1730 MPa and superior but highly inhomogeneous plasticity under uniaxial compression at ambient temperature. Micro-X-ray diffraction shows that compressive loading facilitates crystallization in the monolithic glassy alloy, resulting in room-temperature plasticity. The plastic deformation of the Zr₆₂Cu_15.5Al₁₀Ni_12.5 BMG may be attributed to in situ precipitation of nanocrystals during compression in heavily deformed areas.     

Formation of icosahedral quasicrystals in an annealed Zr65Al7.5Ni10Cu12.5Ag5 metallic glass

The formation and thermal stability of an icosahedral quasicrystalline phase in an annealed Zr₆₅Al_7.5Ni₁₀Cu_12.5Ag₅ metallic glass have been investigated by X-ray diffraction and transmission electron microscopy analyses. It was found that the quasicrystalline phase can precipitate from the glassy state and the supercooled liquid of the alloy over a wide range of annealing temperatures. After optimizing the heat-treatment conditions, the volume fraction of the quasicrystalline phase in the alloy can reach as high as about 80%. Investigation of the thermal stability of the quasicrystalline phase demonstrates that it is very stable when the annealing temperature is below the glass transformation temperature T _g of the alloy.     

The role of attention in the contextual enhancement of visual memory for natural scenes

The role of attention in memory for objects in natural scenes was investigated using a visual memory. In Experiment 1, participants were asked to memorize six cued (to be attended) objects in a natural scene, and were subsequently tested on one of the cued objects. Four types of test scene images were created by jumbling different sections in scene's background: Attended sections changed, unattended sections changed, both sections changed, and both unchanged. In Experiment 2, the procedure was the same as that of the jumble condition except that scenes to be memorized were also jumbled. Results showed that jumbling of attended sections reduced memory performance, whereas jumbling unattended sections did not, irrespective of the regularity of scene to be memorized. This finding suggests that attention plays an important role in mental construction of a natural scene representation, and leads to enhanced visual memory.     

Effectiveness of Group Positive Parenting Program (Triple P) in Changing Child Behavior,Parenting Style,and Parental Adjustment: An Intervention Study in Japan

The purpose of this study is to investigate the effectiveness of a group-based family intervention program known as the Group Positive Parenting Program (Triple P), with families in Japan. Reductions in children’s behavioral problems, changes in dysfunctional parenting practices, and affects on parenting adjustment were examined. Participants of both the intervention and control groups (N = 91 and N = 24, respectively) were recruited from mothers visiting health clinics in Kawasaki City, Kanagawa. Intervention and control groups were assessed in terms of child behavior (Strength and Difficulty Questionnaire, SDQ), parenting style (Parenting Scale, PS), and parenting adjustment (Depression-Anxiety-Stress Scale, DASS; and Parenting Experience Survey, PES), both pre- and postintervention. A repeated measures multivariate analysis of variance was used to determine the intervention’s effects. The SDQ score for the conduct problems subscale indicated a significant intervention effect. In addition, the postintervention scores for all subscales of the PS, the DASS depression subscale and total scores, as well as ratings for perceived difficulty of parenting in the PES, were significantly reduced in the intervention group alone. The PES also revealed that confidence in parenting significantly increased only in the intervention group. Group Triple P is effective in decreasing child conduct problems, dysfunctional parenting practices, depression, anxiety, stress, and the perceived level of parenting difficulty, as well as in improving parenting confidence, among Japanese families.     

Cultural innovation and transmission of tool use in wild chimpanzees: evidence from field experiments

Chimpanzees (Pan troglodytes) are the most proficient and versatile users of tools in the wild. How such skills become integrated into the behavioural repertoire of wild chimpanzee communities is investigated here by drawing together evidence from three complementary approaches in a group of oil-palm nut- (Elaeis guineensis) cracking chimpanzees at Bossou, Guinea. First, extensive surveys of communities adjacent to Bossou have shown that population-specific details of tool use, such as the selection of species of nuts as targets for cracking, cannot be explained purely on the basis of ecological differences. Second, a 16-year longitudinal record tracing the development of nut-cracking in individual chimpanzees has highlighted the importance of a critical period for learning (3–5 years of age), while the similar learning contexts experienced by siblings have been found to result in near-perfect (13 out of 14 dyads) inter-sibling correspondence in laterality. Third, novel data from field experiments involving the introduction of unfamiliar species of nuts to the Bossou group illuminates key aspects of both cultural innovation and transmission. We show that responses of individuals toward the novel items differ markedly with age, with juveniles being the most likely to explore. Furthermore, subjects are highly specific in their selection of conspecifics as models for observation, attending to the nut-cracking activities of individuals in the same age group or older, but not younger than themselves. Together with the phenomenon of inter-community migration, these results demonstrate a mechanism for the emergence of culture in wild chimpanzees.     

The Role of Coping Styles and Self-efficacy in the Development of Dysphoric Mood Among Nursing Students

Coping styles and self-efficacy have been recognized as important determinants of dysphoric mood. The objectives of this study were to determine the influence of these two factors on depression and anxiety in Japanese students. A set of questionnaires, including the Hospital Anxiety and Depression (HAD) Scale, the Coping Inventory for Stressful Situations (CISS), and the Self-efficacy Scale (SES) was distributed to 146 nursing students. Structural equation modelling was conducted to specify the relationships between measured variables. The HAD depression and anxiety scores were predicted by emotion-oriented coping. The HAD depression alone was predicted by avoidance-oriented coping. Self-efficacy scores predicted the emotion-oriented coping and HAD depression scores. Students’ dysphoric moods were influenced by emotional-oriented coping that mediated the effects of low self-efficacy, and self-efficacy also had a direct effect on depression.