High-pressure electrical resistivity behaviour of nanocrystalline perovskite (La,Sr)(Mn,Fe)O3

We report here the electrical resistivity of nanocrystalline perovskite-structured La–Sr manganites as a function of pressures up to 8?GPa, at room temperature. The nanocrystalline perovskite manganites were prepared by the sol–gel technique and found to have crystallite sizes of 12–18?nm. The pressure dependence of the electrical resistivity shows a first-order phase transition at 0.66(2)?GPa and a subtle phase transition between 3.5 and 3.8?GPa. The first-order transition at 0.66?GPa can be related to the transition from localized-electron to band magnetism.     

Individual‐Oriented Relationship Education: An Evaluation Study in Community‐Based Settings

The effects of relationship education aimed at individuals, rather than couples, have not yet been widely investigated. However, increasingly, relationship education is provided to large and diverse groups of individuals who may be in varying stages of relationships. Several programs have been developed to strengthen relationship competencies among single individuals as well as among partnered individuals who, for a variety of reasons, seek relationship education without their partners. The current study is an exploratory evaluation study that examined self‐reported outcomes for 706 single and partnered individuals who attended Within My Reach classes delivered in community‐based agencies. Participants were from diverse backgrounds and exhibited many of the risk factors for poor relationship outcomes including unemployment, low income, and childhood experience of abuse or neglect. Pre‐post analyses indicated that the program was beneficial for both singles and partnered individuals. Singles reported increased belief in ability to obtain healthy relationships. Partnered individuals reported increased relationship quality, relationship confidence, and reduced conflict. Regardless of relationship status, participants also reported improvement in general relationship and communication skill. Results support the utility of individual‐oriented relationship education for singles and partnered individuals with diverse background characteristics.     

Structural stability of W2B5 under high pressure

High-pressure structural stability studies have been carried out on tungsten boride W₂B₅ up to maximum pressure of 36 GPa using a Mao-Bell diamond-anvil cell at beamline BR-12 of the ELETTRA synchrotron facility (λ = 0.68881 Å). The hexagonal phase (S.G:P6₃/mmc) of W₂B₅ is stable up to the maximum pressure studied. The bulk modulus is estimated to be ~347 GPa using the Birch–Murnaghan equation of state. The variation of lattice parameters and bond lengths B–B and W–B have been studied and the c-axis is seen to be marginally more compressible than the a-axis.     

From the Desk of Editor-in-Chief

Journal of Indian Council of Philosophical Research -     

Words can slow down category learning

Words have been shown to influence many cognitive tasks, including category learning. Most demonstrations of these effects have focused on instances in which words facilitate performance. One possibility is that words augment representations, predicting an across the-board benefit of words during category learning. We propose that words shift attention to dimensions that have been historically predictive in similar contexts. Under this account, there should be cases in which words are detrimental to performance. The results from two experiments show that words impair learning of object categories under some conditions. Experiment 1 shows that words hurt performance when learning to categorize by texture. Experiment 2 shows that words also hurt when learning to categorize by brightness, leading to selectively attending to shape when both shape and hue could be used to correctly categorize stimuli. We suggest that both the positive and negative effects of words have developmental origins in the history of word usage while learning categories. [corrected]     

Total sleep deprivation impairs the encoding of trace-conditioned memory in the rat

Sleep may help consolidate the information of certain memories, though its benefits in the consolidation of trace-conditioned memory still remain elusive. We investigated the effect of sleep deprivation on trace learning in male wistar rats. Rats were trained for trace conditioning and the number of head entries into liquid dispenser was accounted as an outcome measure of trace-learning. For training and testing, 75 presentations of conditioned stimulus (CS) (light) and unconditioned stimulus (US) (juice) were offered in five sessions (15 presentations/session; with 5 min inter-session gap). The duration of CS and US stimuli were 15 and 20s respectively, with 5s trace delay between stimuli and 20s condition delay between each presentation. The animals were divided randomly into three groups soon after training, sleep deprived (SD) (n=8), non-SD (NSD) (n=8) and stress control (n=5) groups. The animals of NSD and control groups were left undisturbed, while SD animals were sleep deprived for 6h after training. The learning of trace-conditioned task was examined on following days. We observed that SD rats poked approximately 63% less than NSD and control groups (p<0.001) to obtain juice on testing day. Also, the NSD rats exhibited significant positive correlation in number of head entries during the training and testing days; while the SD rats showed no significant correlation. The results demonstrate that SD animals had difficulties to associate CS with US and suggest that sleep deprivation soon after training impairs the encoding of trace memory.     

The impact of environmental experiences on symptoms of anxiety and depression across the life span

Symptoms of anxiety and depression are relatively stable over time. Can this stability be explained by genetic influences, or is it caused by the long-lasting effects of accumulating environmental experiences? To address this question, we analyzed longitudinally assessed symptoms of anxiety and depression in eight samples of monozygotic twins of widely varying ages. These samples were drawn from American and European population-based registries. Using hierarchical linear modeling, we examined individual differences and individual changes in the level of symptoms over time. This method enabled us to decompose the variance into the predictable variance shared by both members of each pair of twins, the differences between individuals within pairs, and the residual variance. We then modeled how these components of individual variation changed over time. Within pairs, the twins' predicted levels of symptoms increasingly diverged from childhood until late adulthood, at which point the divergence ceased. By middle adulthood, environmental experiences contributed substantially to stable and predictable interindividual differences in levels of anxiety and depression.     

Gender Differences in the Effects of Acute Stress on Spatial Ability

Although reports that men and women differ in spatial ability are common, recent research examining stress effects on spatial navigation have not included analyses of gender differences. The current study investigated cue perception and mental rotation after an acute cold-water hand immersion stress in 156 undergraduates from the western United States. Gender differences were observed in spatial performance and spatial anxiety. Discriminant analysis revealed that distal gradient cue identification and mental rotation reaction times as well as spatial anxiety differed among men and women exposed to the acute stress and their warm-water hand immersion controls. These results indicate that stress differentially alters spatial performance in men and women, and underscores the importance of assessing gender differences when examining spatial ability.