Minding the gap: a sex difference in young infants' mental rotation through thirty degrees of arc.

Mental rotation (MR) is an important feature of spatial cognition invoking mental imagery of an object's appearance when viewed from a new orientation. Prior studies have revealed evidence of MR in infants, including a sex difference similar to that detected in older populations. Some of these studies used visual habituation methods whereby infants were familiarized with an object rotating through a 240° angle, followed by test trials showing either the habituation object or a mirror image object rotating through the previously unseen 120° angle.

The Structure of Cognitive Abilities and Associations with Problem Behaviors in Early Adolescence: An Analysis of Baseline Data from the Adolescent Brain Cognitive Development Study.

Using baseline data ( = 9875) from the Adolescent Brain Cognitive Development (ABCD) Study examining children aged 9 to 10 years, the current analyses included: (1) exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) of neurocognitive measures administered during baseline collection, and (2) linear regression analyses on the Child Behavior Checklist (CBCL), controlling for demographic and socioeconomic factors. The neurocognitive tasks measured episodic memory, executive function (EF; attention), language skills, processing speed, working memory, visuospatial ability, and reasoning. The CBCL included composite scores of parent-reported internalizing, externalizing, and stress-related behavior problems.

Seeing double: 5-month-olds' mental rotation of dynamic, 3D block stimuli presented on dual monitors.

Mental rotation (MR) involves the ability to predict how an object will look once it has been rotated into a new orientation in space. To date, studies of MR in infants have tested this ability using abstract stimuli presented using a single display. Evidence from existing studies suggests that using multiple displays may affect an infant's performance in some kinds of MR tasks.

A yeast recombination-based cloning system to produce chimeric HIV-1 viruses and express HIV-1 genes.

Differential phenotypes or properties of HIV-1 gene products in primary virus isolates are difficult to assess due to interference by the high degree of sequence variation across the entire genome. Thus, chimeric viruses provide a powerful tool to study the function of single gene products or genetic elements in the context of a neutral viral genomic backbone. In this chapter, we describe how to produce HIV-1 chimeric viruses utilizing a yeast-based homologous recombination cloning technique to insert env sequences first into a yeast cloning vector and then into the common pNL4-3 virus backbone.

Changes in human immunodeficiency virus type 1 fitness and genetic diversity during disease progression.

This study examined the relationship between ex vivo human immunodeficiency virus type 1 (HIV-1) fitness and viral genetic diversity during the course of HIV-1 disease. Primary HIV-1 isolates from 10 patients at different time points were competed against control HIV-1 strains in peripheral blood mononuclear cell (PBMC) cultures to determine relative fitness values. Patient HIV-1 isolates sequentially gained fitness during disease at a significant rate that directly correlated with viral load and HIV-1 env C2V3 diversity.

Differences in the fitness of two diverse wild-type human immunodeficiency virus type 1 isolates are related to the efficiency of cell binding and entry.

The ability of one primary human immunodeficiency virus type 1 (HIV-1) isolate to outcompete another in primary CD4+ human lymphoid cells appears to be mediated by the efficiency of host cell entry. This study was designed to test the role of entry on fitness of wild-type HIV-1 isolates (e.g.