Content and Distribution of Organic And Inorganic Carbon in the Urban Soils of Rostov Agglomeration

The content and distribution of organic and inorganic carbon along the profile in the soils of the Rostov agglomeration are considered. The results obtained on a TOC-L CPN Shimadzu carbon analyzer are evaluated using Student's t-test. The groups of some horizons of native soils AU rz, AU, BCA, C, as well as their buried analogues [AU], [BCA], [C] were compared. The analysis of the urbic horizons was carried out taking into account their particle size distribution, previously dividing into horizons clusters - heavy URh and light URl. In the [AU] horizon of soils buried under the anthropogenic stratum, a statistically significant decrease in the organic carbon content is observed, compared to the AU horizon of natural analogues. The middle part of the profile - the BCA and [BCA] horizons - is characterized by the greatest similarity in carbon content, both organic and inorganic, which suggests the lowest anthropogenic impact on these horizons. Significant differences in the inorganic carbon content in the comparison pair - horizons C and [C] are shown, and its content is higher in natural analogues (horizons C). The data analysis of the urbic diagnostic horizons did not reveal any significant regularities because of the high degree of variation of this indicator due to the genesis peculiarities of the anthropogenically transformed stratum.

Cracking the code of place value: The relationship between place and value takes years to master

Place value, which underlies the meanings of multi-digits, encompasses the principle of position and base-10 rules. To understand “65,” one needs to know that the digits “6” and “5” occupy different positions and thus represent ordered values of different magnitudes (the principle of position), and that the value of each position is determined by base-10 rules (e.g., the rightmost position is 10^0, followed by 10^1, 10^2, etc.). Without the principle of position, children cannot construct meanings for multi-digits. Previous studies show that children do not know the exact value of digit positions until early elementary school years, but less is known about the acquisition of positional knowledge for multi-digits. To study when and how children construct a relationship between position and value, this study explored when children begin to know that the leftmost digit represents the largest value, and whether such knowledge relates to learning number names. Four to 7-year-olds from primarily Caucasian, middle-class families were asked to compare different pairs of multi-digits. Some comparisons (e.g., 12 vs. 21) required knowledge of positional property, and some did not (e.g., 35 vs. 36). We found that as a group, 6-year-olds could recruit positional knowledge to compare multi-digits. We also found that children who knew the number names of both of the multi-digits in a comparison pair were above chance on multi-digit comparison. Our results shed light on the developmental steps towards acquiring place-value notation, and highlight a role of learning number names for learning positional property of the place-value notation.

Discovery of a new species of Dryocosmus Giraud, 1859 (Hymenoptera: Cynipidae: Cynipini) on Castanopsis tibetana from China

A new gall wasp species, Dryocosmus liui Pang, Su et Zhu n. sp., is described from Hunan Province, China. The new species forms integral galls on branches of Castanopsis tibetana Hance. The results of morphological comparison, pair-wise genetic distance of mtDNA COI, and phylogenetic analysis based on COI gene sequences did not support treating Chilaspis and Dryocosmus as separate genera. Our results also provided new evidence supporting the notion that the Nearctic Dryocosmus species may represent a lineage distinct from the Old World species of the genus.