Fluid Intelligence Test Scores Across the Schooling: Evidence of Nonlinear Changes in Girls and Boys

We are incredibly grateful for all participants for their contribution to the study. We thank Tatiana Bykovskaya and Olga Kashubina for their technical support.Received 26 April 2022. Accepted 17 August 2022. Published online 10 October 2022.The results of the analyses of the changes of fluid intelligence scores measured by the Standard Progressive Matrices test across all school years were presented. Sex differences in fluid intelligence scores for each year of schooling as well as in fluid intelligence changes across schooling were analyzed. A total of 1581 participants (51.1% boys) aged 6.8 to 19.1 years from one public school were involved in this cross-sectional study, of whom 871 were primary schoolchildren (mean age = 9.23; range 6.8–11.6), 507 were secondary schoolchildren (mean age = 14.06; range 10.8–18.0), and 203 were high schoolchildren (mean age = 17.25; range 15.3–19.1). To examine the changes in fluid intelligence both correlation analysis and polynomial regression of the total, boys’ and girls’ samples were performed. Linear, quadratic, and cubic regression models were fitted to the data. To explore sex differences in fluid intelligence in each year of schooling, the series of ANOVA were carried out. The results revealed that the school-age change in fluid intelligence is nonlinear for both girls and boys. The changes for girls during the schooling are best described by a quadratic relationship while those for boys are best reflected by a cubic relationship.This work was supported by the Russian Science Foundation under Grant number 17-78-30028

Partner symmetries of the complex Monge-Ampere equation yield hyper-Kahler metrics without continuous symmetries

We extend the Mason-Newman Lax pair for the elliptic complex Monge-Amp\`ere equation so that this equation itself emerges as an algebraic consequence. We regard the function in the extended Lax equations as a complex potential. We identify the real and imaginary parts of the potential, which we call partner symmetries, with the translational and dilatational symmetry characteristics respectively. Then we choose the dilatational symmetry characteristic as the new unknown replacing the K\"ahler potential which directly leads to a Legendre transformation and to a set of linear equations satisfied by a single real potential. This enables us to construct non-invariant solutions of the Legendre transform of the complex Monge-Amp\`ere equation and obtain hyper-K\"ahler metrics with anti-self-dual Riemann curvature 2-form that admit no Killing vectors.Comment: submitted to J. Phys.

Effective three-body interactions in the alpha-cluster model for the ^{12}C nucleus

Properties of the lowest $0^{+}$ states of $^{12}\mathrm{C}$ are calculated to study the role of three-body interactions in the $\alpha$-cluster model. An additional short-range part of the local three-body potential is introduced to incorporate the effects beyond the $\alpha$-cluster model. There is enough freedom in this potential to reproduce the experimental values of the ground-state and excited-state energies and the ground-state root-mean-square radius. The calculations reveal two principal choices of the two-body and three-body potentials. Firstly, one can adjust the potentials to obtain the width of the excited $0_2^+$ state and the monopole $0_2^+ \to 0_1^+$ transition matrix element in good agreement with the experimental data. In this case, the three-body potential has strong short-range attraction supporting a narrow resonance above the $0_2^+$ state, the excited-state wave function contains a significant short-range component, and the excited-state root-mean-square radius is comparable to that of the ground state. Next, rejecting the solutions with an additional narrow resonance, one finds that the excited-state width and the monopole transition matrix element are insensitive to the choice of the potentials and both values exceed the experimental ones

New Agrotechnical Methods Development for Planting Material Production and Transplanting Young Grape Plants

The studies aim to evaluate the effect from agrotechnical methods on yield and quality of vegetative young plants that are used with new experimental facility. It provides for different modes in tops and roots zones of the same grafts, which dramatically increases the yield of circular-callus grafts. When using our facility at the end of stratification, when eyes of graft begin to sprout on shoots, they do not stretch out that provides nutrients preservation inside a plant, and grafts are not dried up. The experimental facility is used to grow young plants with a pre-vine trunk in a stratification chamber. A special polymeric-materials support was developed that allows to grow plants in its lower part, to plant them out in a permanent place, to place and hold the sleeves providing by it the yield increase trellis zone. The new method combines previously separated elements of vine-growing technology, starting from growing planting material to using fruit-bearing plantations into a single technological cycle in order to exclude a number of plant care activities, inter alia, protection plants from adverse weather factors, pests and diseases, and mechanical damage [20]

Why do spatial abilities predict mathematical performance?

Spatial ability predicts performance in mathematics and eventual expertise in science, technology and engineering. Spatial skills have also been shown to rely on neuronal networks partially shared with mathematics. Understanding the nature of this association can inform educational practices and intervention for mathematical underperformance. Using data on two aspects of spatial ability and three domains of mathematical ability from 4174 pairs of 12-year-old twins, we examined the relative genetic and environmental contributions to variation in spatial ability and to its relationship with different aspects of mathematics. Environmental effects explained most of the variation in spatial ability (~70%) and in mathematical ability (~60%) at this age, and the effects were the same for boys and girls. Genetic factors explained about 60% of the observed relationship between spatial ability and mathematics, with a substantial portion of the relationship explained by common environmental influences (26% and 14% by shared and non-shared environments respectively). These findings call for further research aimed at identifying specific environmental mediators of the spatial–mathematics relationship

Anti-self-dual Riemannian metrics without Killing vectors, can they be realized on K3?

Explicit Riemannian metrics with Euclidean signature and anti-self dual curvature that do not admit any Killing vectors are presented. The metric and the Riemann curvature scalars are homogenous functions of degree zero in a single real potential and its derivatives. The solution for the potential is a sum of exponential functions which suggests that for the choice of a suitable domain of coordinates and parameters it can be the metric on a compact manifold. Then, by the theorem of Hitchin, it could be a class of metrics on $K3$, or on surfaces whose universal covering is $K3$.Comment: Misprints in eqs.(9-11) corrected. Submitted to Classical and Quantum Gravit

The issue of stability and change of general cognitive abilities in behavioural genetics.

In Russian (References in English

Universal description of the rotational-vibrational spectrum of three particles with zero-range interactions

A comprehensive universal description of the rotational-vibrational spectrum for two identical particles of mass $m$ and the third particle of the mass $m_1$ in the zero-range limit of the interaction between different particles is given for arbitrary values of the mass ratio $m/m_1$ and the total angular momentum $L$. If the two-body scattering length is positive, a number of vibrational states is finite for $L_c(m/m_1) \le L \le L_b(m/m_1)$, zero for $L>L_b(m/m_1)$, and infinite for $L<L_c(m/m_1)$. If the two-body scattering length is negative, a number of states is either zero for $L \ge L_c(m/m_1)$ or infinite for $L<L_c(m/m_1)$. For a finite number of vibrational states, all the binding energies are described by the universal function $\epsilon_{LN}(m/m_1) = {\cal E}(\xi, \eta)$, where $\xi=\displaystyle\frac{N-1/2}{\sqrt{L(L + 1)}}$, $\eta=\displaystyle\sqrt{\frac{m}{m_1 L (L + 1)}}$,and $N$ is the vibrational quantum number. This scaling dependence is in agreement with the numerical calculations for $L > 2$ and only slightly deviates from those for $L = 1, 2$. The universal description implies that the critical values $L_c(m/m_1)$ and $L_b(m/m_1)$ increase as $0.401 \sqrt{m/m_1}$ and $0.563 \sqrt{m/m_1}$, respectively, while a number of vibrational states for $L \ge L_c(m/m_1)$ is within the range $N \le N_{max} \approx 1.1 \sqrt{L(L+1)}+1/2$

Mathematical anxiety: etiology, development, and links with mathematical achievement.

Published in Russian (Russian abstract follows): Математическая тревожность –один из видов эмоциональных реакций, связанных с обучением. Феномен негативно соотносится с математическими способностями и уровнемдостижений в математике. В последнее времяколичество исследований тревожности,связанной с математикой, значительновозросло, что требует обобщенного методологического анализа полученных результатов. В данном обзоре анализируются наиболеезначимые современные исследования математической тревожности и особенностипроявления ее симптоматики. Показана ключевая роль рабочей памяти вфункционировании тревожности и представлен ряд связанных с ней эффектов: «эффект тревожностисложности», «эффект избегания» и «эффект различия». Представлены результаты исследований мозговых механизмов взаимодействия математической тревожности с когнитивными способностями. Исследования показали, что математическая тревожностьсвязана с активностью в областях мозга, связанных с переживанием физической боли,и влияет на эффективность мозговой обработки числовой информации.Показана генетическая и средовая этиология феномена: до 70 %индивидуальных различий в математической тревожности объясняютсясредовыми факторами. Представлены описания семейных, школьных исоциальных факторов, способствующих развитию математическойтревожности. Описаны теоретические представления и результаты экспериментальныхисследований связей конструкта с другими психологическими процессами: мотивацией, самооценкой способностей и др. В работе обсуждаются в том числе положительныеэффекты тревожности: тревожность может вызвать физиологическое состояние «вызов» и темулучшить продуктивность человека. Анализируются методы, используемыедля снижения математической тревожности: экспрессивное письмо, медитация,сменаустановки в отношении математической тревожности. Анализ современных данных показал необходимость дальнейших исследованийматематической тревожности и ее механизмов для разработки болееэффективных методов регуляции негативных эмоцийпо отношению к математике