Informal Mentors and Education: Complementary or Compensatory Resources?

Few studies have examined the impact that mentoring (i.e., developing a special relationship with a non-parental adult) has on educational achievement and attainment in the general population. In addition, prior research has yet to clarify the extent to which mentoring relationships reduce inequality by enabling disadvantaged youth to compensate for a lack of social resources or promote inequality by serving as a complementary resource for advantaged youth. Results from a nationally representative sample of youth show (1) a powerful net influence of mentors on the educational success of youth and (2) how social background, parental, peer, and personal resources condition the formation and effectiveness of mentoring relationships. The findings uncover an interesting paradox—that informal mentors may simultaneously represent compensatory and complementary resources. Youth with many resources are more likely than other young people to have mentors, but those with few resources are likely to benefit more from having a mentor—particularly teacher mentors—in their lives

Helping Relationships and Genetic Propensities: A Combinatoric Study of DRD2, Mentoring, and Educational Continuation

Abstract From conception to death, helping relationships promote positive development and enable people to surmount challenges in their lives. Is it the case that the negative consequences of a genetic propensity for risky behaviors can be attenuated by helping relationships (a G × E)? But is it also the case that people with such a genetic propensity are less likely to have helping relationships compared to people without such a propensity (a rGE)? We illustrate this complex pattern of gene–environment interplay by drawing on the National Longitudinal Study of Adolescent Health and a combinatoric analytic strategy. We focus on a gene associated with dopamine receptor type 2 (DRD2 TaqIA), student–mentor relationships, and educational continuation beyond secondary school. Results reveal that, for both white and black males, DRD2 A1+ (A1A1 and A1A2 genotypes) is associated with a decreased likelihood of school continuation compared to their counterparts with DRD2 A1–; mentors who are teachers compensate for this negative association (a G × E); and youth with DRD2 A1+ are less likely to have a mentor who is a teacher than their counterparts with DRD2 A1– (a rGE)

Short-Term Memory Trace in Rapidly Adapting Synapses of Inferior Temporal Cortex

Visual short-term memory tasks depend upon both the inferior temporal cortex (ITC) and the prefrontal cortex (PFC). Activity in some neurons persists after the first (sample) stimulus is shown. This delay-period activity has been proposed as an important mechanism for working memory. In ITC neurons, intervening (nonmatching) stimuli wipe out the delay-period activity; hence, the role of ITC in memory must depend upon a different mechanism. Here, we look for a possible mechanism by contrasting memory effects in two architectonically different parts of ITC: area TE and the perirhinal cortex. We found that a large proportion (80%) of stimulus-selective neurons in area TE of macaque ITCs exhibit a memory effect during the stimulus interval. During a sequential delayed matching-to-sample task (DMS), the noise in the neuronal response to the test image was correlated with the noise in the neuronal response to the sample image. Neurons in perirhinal cortex did not show this correlation. These results led us to hypothesize that area TE contributes to short-term memory by acting as a matched filter. When the sample image appears, each TE neuron captures a static copy of its inputs by rapidly adjusting its synaptic weights to match the strength of their individual inputs. Input signals from subsequent images are multiplied by those synaptic weights, thereby computing a measure of the correlation between the past and present inputs. The total activity in area TE is sufficient to quantify the similarity between the two images. This matched filter theory provides an explanation of what is remembered, where the trace is stored, and how comparison is done across time, all without requiring delay period activity. Simulations of a matched filter model match the experimental results, suggesting that area TE neurons store a synaptic memory trace during short-term visual memory

Artificial Polyploidy Improves Bacterial Single Cell Genome Recovery

BACKGROUND: Single cell genomics (SCG) is a combination of methods whose goal is to decipher the complete genomic sequence from a single cell and has been applied mostly to organisms with smaller genomes, such as bacteria and archaea. Prior single cell studies showed that a significant portion of a genome could be obtained. However, breakages of genomic DNA and amplification bias have made it very challenging to acquire a complete genome with single cells. We investigated an artificial method to induce polyploidy in Bacillus subtilis ATCC 6633 by blocking cell division and have shown that we can significantly improve the performance of genomic sequencing from a single cell. METHODOLOGY/PRINCIPAL FINDINGS: We inhibited the bacterial cytoskeleton protein FtsZ in B.subtilis with an FtsZ-inhibiting compound, PC190723, resulting in larger undivided single cells with multiple copies of its genome. qPCR assays of these larger, sorted cells showed higher DNA content, have less amplification bias, and greater genomic recovery than untreated cells. SIGNIFICANCE: The method presented here shows the potential to obtain a nearly complete genome sequence from a single bacterial cell. With millions of uncultured bacterial species in nature, this method holds tremendous promise to provide insight into the genomic novelty of yet-to-be discovered species, and given the temporary effects of artificial polyploidy coupled with the ability to sort and distinguish differences in cell size and genomic DNA content, may allow recovery of specific organisms in addition to their genomes

The association between air pollutants and hippocampal volume from magnetic resonance imaging: A systematic review and meta-analysis

Growing epidemiological evidence suggests that air pollution may increase the risk of cognitive decline and neurodegenerative disease. A hallmark of neurodegeneration and an important diagnostic biomarker is volume reduction of a key brain structure, the hippocampus. We aimed to investigate the possibility that outdoor air nitrogen dioxide (NO2) and particulate matter with diameter ≤2.5 μm (PM2.5) and ≤10 μm (PM10) adversely affect hippocampal volume, through a meta-analysis. We considered studies that assessed the relation between outdoor air pollution and hippocampal volume by structural magnetic resonance imaging in adults and children, searching in Pubmed and Scopus databases from inception through July 13, 2021. For inclusion, studies had to report the correlation coefficient along with its standard error or 95% confidence interval (CI) between air pollutant exposure and hippocampal volume, to use standard space for neuroimages, and to consider at least age, sex and intracranial volume as covariates or effect modifiers. We meta-analyzed the data with a random-effects model, considering separately adult and child populations. We retrieved four eligible studies in adults and two in children. In adults, the pooled summary β regression coefficients of the association of PM2.5, PM10 and NO2 with hippocampal volume showed respectively a stronger association (summary β -7.59, 95% CI -14.08 to -1.11), a weaker association (summary β -2.02, 95% CI -4.50 to 0.47), and no association (summary β -0.44, 95% CI -1.27 to 0.40). The two studies available for children, both carried out in preadolescents, did not show an association between PM2.5 and hippocampal volume. The inverse association between PM2.5 and hippocampal volume in adults appeared to be stronger at higher mean PM2.5 levels. Our results suggest that outdoor PM2.5 and less strongly PM10 could adversely affect hippocampal volume in adults, a phenomenon that may explain why air pollution has been related to memory loss, cognitive decline, and dementia

Family predictors of adolescent substance use: the case of high school students in the Cape Metropolitan Area, Cape Town, South Africa

Family predictors of tobacco and alcohol use were studied in random samples of school-going Black, Coloured, and White adolescents (total N=1,800) in the Cape Town Metropolitan Area. The subjects ranged in age from 14 to 17 years, with a mean age of 15.95 years. Logistic regression analysis of the data showed invariance across the three racial groups in terms of the specific family variables that were predictive, as well as their direction and magnitude of association with substance use. Essentially, higher rates of substance use for all three groups were predicted by parental behavioural control, parental monitoring/knowledge and limit setting, marital relations and family stress. The findings extend the work on South African adolescent substance use by providing a view into the proximal (family) socialising forces that are related to substance use. The findings also extend the broader work on identifying specialised effects of dimensions of socialization on adolescent functioning. The discussion section includes commentary on the cultural invariance found when measuring socialising forces at this level of generality.Journal of Child and Adolescent Mental Health 2006, 18(1): 7–1

Interaction between Helicobacter pylori and latent toxoplasmosis and demographic variables on cognitive function in young to middle-aged adults.

Helicobacter pylori and latent toxoplasmosis are widespread diseases that have been associated with cognitive deficits and Alzheimer's disease. We sought to determine whether interactions between Helicobacter pylori and latent toxoplasmosis, age, race-ethnicity, educational attainment, economic status, and general health predict cognitive function in young and middle-aged adults. To do so, we used multivariable regression and multivariate models to analyze data obtained from the United States' National Health and Nutrition Examination Survey from the Centers for Disease Control and Prevention, which can be weighted to represent the US population. In this sample, we found that 31.6 percent of women and 36.2 percent of men of the overall sample had IgG Antibodies against Helicobacter pylori, although the seroprevalence of Helicobacter pylori varied with sociodemographic variables. There were no main effects for Helicobacter pylori or latent toxoplasmosis for any of the cognitive measures in models adjusting for age, sex, race-ethnicity, educational attainment, economic standing, and self-rated health predicting cognitive function. However, interactions between Helicobacter pylori and race-ethnicity, educational attainment, latent toxoplasmosis in the fully adjusted models predicted cognitive function. People seropositive for both Helicobacter pylori and latent toxoplasmosis - both of which appear to be common in the general population - appear to be more susceptible to cognitive deficits than are people seropositive for either Helicobacter pylori and or latent toxoplasmosis alone, suggesting a synergistic effect between these two infectious diseases on cognition in young to middle-aged adults

Association between Toxoplasma gondii seropositivity and serointensity and brain volume in adults: A cross-sectional study.

The intracellular protozoal parasite Toxoplasma gondii has been associated with worsened cognitive function in animal models and in humans. Despite these associations, the mechanisms by which Toxoplasma gondii might affect cognitive function remain unknown, although Toxoplasma gondii does produce physiologically active intraneuronal cysts and appears to affect dopamine synthesis. Using data from the UK Biobank, we sought to determine whether Toxoplasma gondii is associated with decreased prefrontal, hippocampal, and thalamic gray-matter volumes and with decreased total gray-matter and total white-matter volumes in an adult community-based sample. The results from adjusted multivariable regression modelling showed no associations between Toxoplasma gondii and prefrontal, hippocampal, and thalamic brain gray-matter volumes. In contrast, natural-log transformed antibody levels against the Toxoplasma gondii p22 (b = -3960, 95-percent confidence interval, -6536 to -1383, p < .01) and sag1 (b = -4863, 95-percent confidence interval, -8301 to -1425, p < .01) antigens were associated with smaller total gray-matter volume, as was the mean of natural-log transformed p22 and sag1 titers (b = -6141, 95-percent confidence interval, -9886 to -2397, p < .01). There were no associations between any of the measures of Toxoplasma gondii and total white-matter volume. These findings suggest that Toxoplasma gondii might be associated with decreased total gray-matter in middle-aged and older middle-aged adults in a community-based sample from the United Kingdom

Informal mentoring and young adult employment

This study explores the role of informal mentoring (i.e., developing an important relationship with a non-parental adult) in the transition to full time employment among young adults (age 23–28). Multivariate analysis of the Add Health data reveals that mentoring is positively related to the likelihood of full time employment, and the relationship involves both selection and causation processes. Entrance into the world of work facilitates the development of mentoring relationships, especially among youth who identify work-related mentors after adolescence. These relationships have the potential for promoting attachment to the labor force. Mentoring relationships that develop outside of work settings and during adolescence have a positive impact on the odds of full time employment. The receipt of guidance and advice from mentors, as well as access to weak-tied mentoring relationships, teacher mentors, and friend mentors all contribute to the increased odds of employment in young adulthood. However, adolescent mentoring may be less effective among young women than it is among young men