"Honestly, they are just like us": U.S. parents choose middle-class gender and racial ingroup peers for their children.

Children and adolescents benefit from positive intergroup peer interactions, but they are unlikely to have many opportunities for these interactions if their parents are uncomfortable with them. Drawing primarily on social identity theory (SIT), this study investigated how U.S. parents' (N = 569) comfort with their children's potential intergroup peer interactions (a) differed by child and peer group gender (boy, girl), race (Black, White), and social class (higher-, middle-, or lower-subjective social status), (b) changed over the transition from childhood to adolescence (8-10, 11-13, and 14-16 years), and (c) varied by context intimacy (hanging out vs. sleeping over). The sample was equally balanced between parents of children reflecting those same group memberships. Consistent with SIT, when asked to choose, parents were typically most comfortable with their child spending time with middle-class peers who shared their child's gender and racial ingroup membership. Moreover, parents often explained their decisions with reference to similarities between these peers and their own child or family. Parents' comfort did not differ systematically by child age, but many parents were less comfortable with cross-gender peer interactions in the more intimate sleepover context than the less intimate hangout context. All groups of parents also exhibited at least some openness to cross-group interactions. These findings advance developmental scientists' understanding of parents' roles as potential facilitators or gatekeepers of their children's intergroup peer interactions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

"This kid looks like he has everything": 3- to 11-year-old children's concerns for fairness and social preferences when peers differ in social class and race.

This study investigated 3- to 11-year-old US children's (N = 348) perceptions of access to resources, social group preferences, and resource distribution decisions and reasoning when hypothetical peers differed in social class (poor or rich) and race (Black or White). Data were collected in 2019. The sample reflected the region where data were collected in terms of gender (44% girls, 30% boys, 1% another identity) and race and ethnicity (46% White, 10% multiracial or multiethnic, 9% Black, 5% Latinx, 2% Asian, 3% another identity), and parents reported a higher average level of education than the regional average. Results revealed both marked age differences in children's perceptions, preferences, decisions, and reasoning and specific combinations of peer group memberships that were especially likely to receive preferential treatment. With age, children perceived that rich peers had greater access to resources than poor peers, but when both peers were poor, White peers were perceived to have more resources than Black peers. Social group preferences changed with age, from mixed social class and racial group preferences, to preferences for rich peers, to dislike for rich peers. Resource allocation decisions and reasoning reflected both social group and fairness concerns: young children distributed more to White peers especially if they were also rich, participants in middle childhood explicitly favored rich peers regardless of their race, and older children distributed more to poor peers and reasoned about either moral concerns for equity or social class stereotypes. Thus, overall, younger children's responses often reflected broader economic and racial inequalities while older children often sought to create more equity, though not always for moral reasons.

Copper activity in soil solutions of calcareous soils.

Copper partitioning was studied in seven calcareous soils at moisture content corresponding to 1.2 times the field moisture content (soil water potential 7.84 J kg(-1)). Copper retention was accompanied by the release in soil solution of Ca(2+), Mg(2+), Na(+), and H(+), and the total amount of these cations released was 0.8 to 1.09 times the amount of Cu sorbed (mol(c):mol(c)). The relationships between Cu activity and pH, and the balance of cations in soils correspond with the surface precipitation of CuCO(3) as the main mechanism of Cu retention. The values of ion activity product of surface precipitate were close for all studied soils with the average log(IAP(CuCO(3)))=-15.51. The relationship between copper activity in soil solutions and soil properties is well fit by a regression relating pCu (-log copper ion activity) with soil pH, total Cu, and carbonate content.

In vitro biotransformation of an arsenosugar by mouse anaerobic cecal microflora and cecal tissue as examined using IC-ICP-MS and LC-ESI-MS/MS.

This investigation examined chemical and microbiological transformations of an arsenosugar by mouse cecum. To mimic the low oxygen environment in the mammalian gastrointestinal tract, reaction mixtures were incubated under anaerobic conditions. An arsenosugar extracted from ribbon kelp, 3-[5'-deoxy-5-(dimethylarsinoyl)-beta-ribofuranosyloxy]-2-hydroxypropanesulfonic acid, As392, was added to reaction mixtures that contained either cecal microflora or cecal tissue homogenate. These reaction mixtures were incubated at 0 or 37 degrees C for up to 48 hours to monitor biotransformation of the arsenosugar. Analysis of the reaction mixtures by IC-ICP-MS and LC-ESI-MS/MS indicated that the arsenosugar was converted primarily (95%) to its sulfur analog in less than 1 h at 37 degrees C. Conversion of As392 to its sulfur analog was much slower at 0 degrees C (21% conversion after 48 h). In reaction mixtures with cecal tissue homogenate, conversion of As392 to its sulfur analog was slower (77% conversion after 48 h at 37 degrees C). A good mass balance was found in all reaction mixtures between the amount of arsenosugar added and the sum of all detected arsenic-containing products. LC-ESI-MS/MS spectra of the sulfur-containing arsenosugar formed in all reaction mixtures containing cecal microflora compared well with those of a synthetic standard. These results suggest that the anaerobic microflora of the gastrointestinal tract can rapidly convert ingested arsenosugars to sulfur analogs. This biotransformation may affect the subsequent absorption, metabolism, and disposition of arsenic present in arsenosugars.

Effect of soil properties on copper release in soil solutions at low moisture content.

Copper partitioning at moisture content of 1.2-fold the field moisture capacity (corresponding to a soil water potential of 7.84 J/kg; pF = 1.9) was studied in 11 soils with pH 3.4 to 6.8 and an organic matter content of 4.1 to 233 g C/kg. Soil solutions were separated with the centrifuge method and analyzed to determine pH, Cu2+ activity, dissolved organic carbon, and Cu, Ca, Mg, and Na concentrations. Soil organic matter content, total Cu content, and soil pH were the main variables explaining variation in Cu activity in soil solutions. Based on total Cu, soil organic matter content, and soil solution pH, the Windermere Humic Aqueous Model (WHAM) VI assemblage model provided estimates of Cu2+ activity, {Cu2}, with a root mean square error of the predicted pCu (i.e., -log{Cu2+}) of 0.77.

Comparison of a chemical and enzymatic extraction of arsenic from rice and an assessment of the arsenic absorption from contaminated water by cooked rice.

Rice is a target food for arsenic speciation based analyses because of its relatively high arsenic concentration and per capita consumption rates. Improved speciation data for rice can be helpful in estimating inorganic arsenic exposures in the U.S. and in endemic populations. The inorganic arsenic exposure for cooked rice should include both the arsenic in raw rice plus the arsenic absorbed from the water used to prepare it. The amount of arsenic absorbed from water by rice during preparation was assessed using five different types of rice cooked in both contaminated drinking water and arsenic-free reagent water. The rice samples were extracted using trifluoroacetic acid (TFA) and speciated using IC-ICP-MS. The TFA procedure was able to extract 84-104% of the arsenic (As) from the five different cooked rice samples. Chromatographic recoveries ranged from 99% to 116%. The dimethylarsinic acid (DMA) and inorganic arsenic concentration ranged from 22 to 270 ng of As/g of rice and from 31 to 108 ng of As/g of rice, respectively, for samples cooked in reagent water. The overall recoveries, which relate the sum of the chromatographic species back to the total digested concentration, ranged from 89% to 117%. The absorption of arsenic by rice from the total volume of water [1:1 to 4:1 (water:rice)] used in cooking was between 89% and 105% for two different contaminated drinking water samples. A comparison of the TFA extraction to an enzymatic extraction was made using the five rice samples and NIST 1568a rice flour. The two extraction procedures produced good agreement for inorganic arsenic, DMA, and the overall recovery. Through the use of IC-ESI-MS/ MS with a parent ion of m/z 153 and fragment ions of m/z 138, 123, and 105, the structure dimethylthioarsinic acid was tentatively identified in two of the rice samples using the enzymatic extraction.

Intraspecific variation in fem-3 and tra-2, two rapidly coevolving nematode sex-determining genes.

The sex determination gene fem-3 encodes one of the most divergent proteins yet described in the terrestrial nematode Caenorhabditis. Despite this rapid sequence change, however, FEM-3 is essential for male development in the three species surveyed thus far. It also participates in conserved protein-protein complexes with the transmembrane receptor TRA-2 and the phosphatase FEM-2 in these species. These interactions show strong species specificity, indicating that conserved residues are not sufficient for function and that compensatory evolution between binding partners is important. To shed further light on the nature of this coevolution, and to discern the extent of amino acid polymorphism allowed in FEM-3 and the domain of TRA-2 that binds it, we have examined intraspecific variation in the gonochoristic species Caenorhabditis remanei. Ten new complete Cr-fem-3 alleles from three regions of the United States are described. We also obtained sequences for the FEM-3-binding domain of TRA-2 for 9 of the same strains. These alleles were compared with each other, with the European founder alleles, and with the orthologous sequences from the congeners Caenorhabditis elegans and C. briggsae. We find that FEM-3 harbors abundant amino acid polymorphisms along its entire length. The majority (but not all) of these occur in nonconserved residues, and in at least one domain there is evidence for diversifying selection. The FEM-3-binding domain of TRA-2 is less polymorphic than FEM-3. Amino acids neither polymorphic nor conserved between species are candidates for residues mediating species-specific interaction of FEM-3 with its binding partners.