Оазис для ума и сердца

.

Biochemical markers of vital biodestruction in common oak (Quercus robur)

The wood of the common oak (Quercus robur L.) has high mechanical strength, elasticity and resistance to fracture. However, constitutional stability is not always able to provide the plants with reliable protection from wood-decay fungi, and the initial stages of biodegradation are difficult to determine. Therefore, this study concerns research on appropriate biochemical markers for early diagnostics of wood defects. The total content of phenolic compounds in leaves and wood was determined by a spectrophotometer Optizen Pop using Folin & Ciocalteu’s phenol reagent; the flavonoid content in leaves – by adding solutions of aluminum chloride and sodium acetate to methanolic extracts; catechins content – by the reaction with vanillin reagent; the concentration of phenolic antioxidants – by Brand Williams; chlorophyll and carotenoids’ contents in leaves – by the formula for methanol extracts; the qualitative composition of phenolic compounds – by high performance liquid chromatography and highly effective thin-layer chromatography. During the planned felling of oak trees on the territory of the Boyar Forest Research Station, trees were found with signs of brown streak and biodestruction of wood. Brown streak in wood is caused by a polycondensation of phenolic compounds, which are deposited on the internal surfaces of tracheal elements. In cases of an increase in the total amount of oxidized polyphenols, the cell walls are also stained. Active oxidation processes in wood have a systemic nature for the plants and affect the physiological state of the assimilation apparatus. We determined that in leaves of the trees with signs of brown streak the total phenol content increases in comparison with the control by 1.6 times, as well as flavonoid and catechin content. Our research has shown that the complex of plastid pigments in common oak leaves does not significantly change in the early stages of destructive processes. Increase of brown streak and appearance of rot in wood are associated with slight increase in chlorophyll a to b ratio in leaves. Chromatographic profiling of the leaves showed that the presence of brown streak changes the content of individual phenolic compounds. The trees with brown rot have more substances with UV spectrum characteristic for kaempferol glycosides compared to the control. The results have shown that the biochemical profiles of the trees with signs of brown streak and brown rot differ from the control by the composition of low and medium polar compounds. The absence or presence of some individual phenolic components and their ratio in the leaves are considered as biochemical markers of hidden wood defects

Applicability of the Online Short Spatial Ability Battery to university students testing

Introduction. Multiple studies advocate an importance of spatial abilities (SA) for educational and occupational success, especially in STEM. Recently an Online Short Spatial Ability Battery (OSSAB) was developed and normed for SA testing in adolescents. The battery includes mechanical reasoning, paper folding, pattern assembly, and shape rotation tests. The battery has shown good psychometric characteristics (high reliability and validity, low redundancy, discriminative power), and is available in open access and free to use. Aim. The present research aims: 1) to examine the applicability of the OSSAB for university student testing; 2) to describe its psychometric properties and structure; and 3) to investigate links between SA and educational performance. Methods. A total of 772 university students (aged from 18 to 26, mean age (SD) = 19.55 (1.51), 63.1% females) participated in the study. Participants provided information about their age, gender, university major, and academic achievement, and completed a battery of tests that included the OSSAB tests. Results. The study reports psychometric norms for using the OSSAB in university students. Students’ performance in the OSSAB was similar to that shown in previous research in adolescents in terms of means and variance. The OSSAB showed adequate psychometric properties in this sample: no floor or ceiling effects; low redundancy; moderate to high internal consistency; high discriminative power across university majors; and high external validity. The results indicated that around 6% of the students showed very high levels of SA (higher than 1.5 SD above the mean), and around 8% of students showed very low levels of SA (lower than 1.5 SD below mean). In addition, the OSSAB scores were linked to educational profile choice and exam scores, with small-to-medium effect sizes. Scientific novelty. The study provides psychometric norms for a short online open measure of spatial ability in university students. Practical significance. The OSSAB can be used to provide individual recommendations to students (e.g. SA training), to identify spatially gifted students, and for research purposes in university contexts

Maths Anxiety Does Not Moderate the Link Between Spatial and Maths Ability

Spatial ability (SA) is known to be closely related to mathematical ability (Tosto et al., 2014). Maths anxiety (MA) has been shown to affect both mathematical and spatial ability (Maloney, 2011). The present study investigated the relationship between maths performance and spatial ability, as well as the effects of MA and gender on the association between them. General cognitive ability and trait anxiety were added as control variables. Data were collected from 146 twins (32% males) aged 17-33. Maths performance was measured with Problem Verification Task (PVT). SA was measured with Mental rotation task. MA was measured with sMARS questionnaire. General cognitive ability was measured with Raven’s matrices. Trait anxiety was measured with Spielberger anxiety rating scale. There were no correlations between SA and maths performance, except a negative correlation between SA and PVT reaction time variance. MA did not moderate the association between SA and maths performance. Interestingly, the interaction term between trait anxiety and SA was significant as a predictor for PVT reaction time. Posthoc analysis showed that higher spatial ability was associated with lower reaction time in PVT for high trait anxiety individuals only. Neither main effects of gender and maths anxiety, nor the interaction term between them were significant while predicting spatial ability. Altogether, our results indicate that the interplay between anxiety and mathematical cognition is complex and requires further research

Динамика распространенности бронхиальной астмы у детей в Новосибирске

Six-year dynamics of epidemiology of bronchial asthma was analyzed in Novosibirsk according to a common standardized protocol of the "International Study of Asthma and Allergic Diseases in Children" (ISAAC) programme. The pathology spread was studied using a total surveying among first-form and eight-form pupils (the survey involved 7291 pupils 1996, 6631 ones in 1999 and 6943 children in 2002). The results showed stable spread of bronchial asthma symptoms among the senior and junior pupils and prevalence of mild asthma with rare exacerbations in both the groups. A progredient growth of severe asthma attack rate was noted in eight-form pupils. An increase in frequency of combined upper and lower airway pathologies was registered with reduction in skin atopy rate. A problem of underestimating of the pathology was discussed.Исследована 6-летняя динамика эпидемиологии бронхиальной астмы по единым стандартизованным протоколам программы "Международное исследование астмы и аллергических заболеваний у детей" (ISAAC) в Новосибирске. Изучение распространенности патологии проводилось при сплошном анкетировании учеников 1-х и 8-х классов (7291 школьник в 1996 г., 6631 — в 1999 г. и 6943 — в 2002 г.). В динамике выявлены стабильная распространенность симптомов бронхиальной астмы у старших и младших школьников, сохранение преобладания легких редко рецидивировавших форм патологии в обеих возрастных группах. Отмечен прогредиентный рост тяжелых приступов удушья у восьмиклассников. В популяции школьников зарегистрировано увеличение сочетанного поражения верхних и нижних отделов респираторного тракта с сокращением частоты кожных форм атопии. Отражена проблема гиподиагностики патологии

Linking collisional and accretionary orogens during Rodinia assembly and breakup: Implications for models of supercontinent cycles

Periodic assembly and dispersal of continental fragments has been a characteristic of the solid Earth for much of its history. Geodynamic drivers of this cyclic activity are inferred to be either top-down processes related to near surface lithospheric stresses at plate boundaries or bottom-up processes related to mantle convection and, in particular, mantle plumes, or some combination of the two. Analysis of the geological history of Rodinian crustal blocks suggests that internal rifting and breakup of the supercontinent were linked to the initiation of subduction and development of accretionary orogens around its periphery. Thus, breakup was a top-down instigated process. The locus of convergence was initially around north-eastern and northern Laurentia in the early Neoproterozoic before extending to outboard of Amazonia and Africa, including Avalonia–Cadomia, and arcs outboard of Siberia and eastern to northern Baltica in the mid-Neoproterozoic (~760 Ma). The duration of subduction around the periphery of Rodinia coincides with the interval of lithospheric extension within the supercontinent, including the opening of the proto-Pacific at ca. 760 Ma and the commencement of rifting in east Laurentia. Final development of passive margin successions around Laurentia, Baltica and Siberia was not completed until the late Neoproterozoic to early Paleozoic (ca. 570–530 Ma), which corresponds with the termination of convergent plate interactions that gave rise to Gondwana and the consequent relocation of subduction zones to the periphery of this supercontinent. The temporal link between external subduction and internal extension suggests that breakup was initiated by a top-down process driven by accretionary tectonics along the periphery of the supercontinent. Plume-related magmatism may be present at specific times and in specific places during breakup but is not the prime driving force. Comparison of the Rodinia record of continental assembly and dispersal with that for Nuna, Gondwana and Pangea suggests grouping into two supercycles in which Nuna and Gondwana underwent only partial or no break-up phase prior to their incorporation into Rodinia and Pangea respectively. It was only after this final phase of assembly that the supercontinents then underwent full dispersal

The Factorial Structure of Spatial Abilities in Russian and Chinese Students

Background: Recent research suggested a unifactorial structure of spatial ability (SA). Research is needed to replicate this finding in different populations. Objective: This study aims to explore the factorial structure of SA in samples of 921 Russian and 229 Chinese university students. Design: A gamified spatial abilities battery was administered to all participants. The battery consists of 10 different domains of SA, including 2D and 3D visualization, mental rotation, spatial pattern assembly, spatial relations, spatial planning, mechanical reasoning, spatial orientation and spatial decision making speed and flexibility. Results: The results of the factor analysis showed a somewhat different pattern for different samples. In the Russian sample, the unifactorial structure, shown previously in a large UK sample (Rimfeld et al., 2017), was replicated. A single factor explained 40% of the variance. In the Chinese sample two factors emerged: first factor explained 26% of the variance and the second factor, including only Mechanical reasoning and Cross-Sections tests, explained 14%. The results also showed that the Chinese sample significantly outperformed the Russian sample in 5 out of the 10 tests. Russian students showed better performance only in two of the tests. The effects of all group comparisons were small. Conclusion: Overall, a similar amount of variance in the 10 tests was explained in the two samples, replicating results from the UK sample. Future research is needed to explain the observed differences in the structure of SA