Immune responses to lipopolysaccharide challenge in a tropical rodent (Funambulus pennanti): photoperiod entrainment and sex differences

Annual variation in day length (photoperiod) triggers changes in the immune system of seasonal breeders. The rationale behind this study was to delineate any sex differences in immune responses of photoperiodically entrained animals challenged against lipopolysaccharide (LPS)-induced inflammatory stress. We observed that photoperiodically entrained [short day, SD, 10?h light (L):14?h dark (D); long day, LD, 16?h L:8?h D; and natural day length, NDL, 12?h L:12?h D] male and female Indian palm squirrels, Funambulus pennanti, presented sexual dimorphism in immune status after LPS-induced stress. Females presented high humoral (anti-keyhole limpet hemocyanin immunoglobulin) and cellular immunity (lymphocyte proliferation) compared with the males of all photoperiodic conditions. Female squirrels showed reduced pro-inflammatory cytokine levels (interleukin-1β, interleukin-6, and tumor necrosis factor-α) than the males suggesting their high efficiency to recover from LPS-induced inflammatory stress. Increased duration of melatonin secretion and corticosterone concentration in squirrels experiencing SD evidently supported survival of squirrels as compared with control (NDL) and LD squirrels of both sexes. Decreased immune status in both sexes under LD condition might be due to a short melatonin signal mimicking the LDs of summer. Thus, we infer that photoperiodic entrainment via the levels of melatonin and corticosterone synergistically supported more the survival of female squirrels under LPS-induced stress.     

Cross‐cultural comparison of seven morningness and sleep–wake measures from Germany,India and Slovakia

Morningness–eveningness or circadian typology can be viewed as an interesting aspect of individual differences. Morningness–eveningness is a preference for a given time of day for physical or mental performance, but also reflects aspects of affect. Here, we used seven different measures to assess differences in morningness–eveningness between Germany, Slovakia and India. The hypothesis was that Indians should be earliest chronotypes, followed by Slovakia and then Germany, because of higher temperatures in India, and the fact that Slovakia is located farther east compared to Germany. We applied the Composite Scale of Morningness (CSM), the Circadian Energy Scale (CIRENS), the CAEN Chronotype Questionnaire (CCQ), and habitual sleep–wake variables to calculate sleep duration, midpoint of sleep and social jetlag. Sample sizes were N = 300 (Germany), N = 482 (Slovakia) and N = 409 (India). Country had the strongest influence on morningness–eveningness. Germans were latest chronotypes and differed in all seven measures from Indians but differed from Slovakians only in the energy level at the evening and midpoint of sleep. Slovakians and Indians differed in all measures but the energy level (CIRENS). Women scored higher on the CSM, lower on CIRENS, lower on the morningness–eveningness (ME) scale, but higher on distinctness (DI) scale. Women slept longer and had an earlier midpoint of sleep.     

Supporting Generative Thinking About the Integer Number Line in Elementary Mathematics

This report provides evidence of the influence of a tutorial “communication game” on fifth graders’ generative understanding of the integer number line. Students matched for classroom and pretest score were randomly assigned to a tutorial (n = 19) and control group (n = 19). The tutorial group students played a 13-problem game in which student and tutor each were required to mark the same position on a number line but could not see one another's activities. To resolve discrepant solutions, tutor and student constructed agreements about number line principles and conventions to guide subsequent placements. Pre-/posttest contrasts showed that (a) tutorial students gained more than controls and (b) agreement use predicted gain. Analyses of micro-constructions during play revealed properties of student learning trajectories.