Race, Income, and College in 25 Years: The Continuing Legacy of Segregation and Discrimination

The rate at which racial gaps in pre-collegiate academic achievement can plausibly be expected to erode is a matter of great interest and much uncertainty. In her opinion in Grutter v. Bollinger, Supreme Court Justice O'Connor took a firm stand: "We expect that 25 years from now, the use of racial preferences will no longer be necessary . . ." We evaluate the plausibility of Justice O'Connor's forecast, by projecting the racial composition and SAT distribution of the elite college applicant pool 25 years from now. We focus on two important margins: First, changes in the black-white relative distribution of income, and second, narrowing of the test score gap between black and white students within family income groups. Other things equal, progress on each margin can be expected to reduce the racial gap in qualifications among students pursuing admission to the most selective colleges. Under plausible assumptions, however, projected economic progress will not yield nearly as much racial diversity as is currently obtained with race-sensitive admissions. Simulations that assume additional increases in black students' test scores, beyond those deriving from changes in family income, yield more optimistic estimates. In this scenario, race-blind rules approach the black representation among admitted students seen today at moderately selective institutions, but continue to fall short at the most selective schools. Maintaining a critical mass of African American students at the most selective institutions would require policies at the elementary and secondary levels or changes in parenting practices that deliver unprecedented success in narrowing the test score gap in the next quarter century.

Race, Income and College in 25 Years: The Continuing Legacy of Segregation and Discrimination

The rate at which racial gaps in pre-collegiate academic achievement can plausibly be expected to erode is a matter of great interest and much uncertainty. In her opinion in Grutter v. Bollinger, Supreme Court Justice O’Connor took a firm stand: “We expect that 25 years from now, the use of racial preferences will no longer be necessary . . .” We evaluate the plausibility of Justice O’Connor’s forecast, by projecting the racial composition and SAT distribution of the elite college applicant pool 25 years from now. We focus on two important margins: First, changes in the black-white relative distribution of income, and second, narrowing of the test score gap between black and white students within family income groups. Other things equal, progress on each margin can be expected to reduce the racial gap in qualifications among students pursuing admission to the most selective colleges. Under plausible assumptions, however, projected economic progress will not yield nearly as much racial diversity as is currently obtained with race-sensitive admissions. Simulations that assume additional increases in black students’ test scores, beyond those deriving from changes in family income, yield more optimistic estimates. In this scenario, race-blind rules approach the black representation among admitted students seen today at moderately selective institutions, but continue to fall short at the most selective schools. Maintaining a critical mass of African American students at the most selective institutions would require policies at the elementary and secondary levels or changes in parenting practices that deliver unprecedented success in narrowing the test score gap in the next quarter century.

Photovoltaic Performance of Ultrasmall PbSe Quantum Dots

We investigated the effect of PbSe quantum dot size on the performance of Schottky solar cells made in an ITO/PEDOT/PbSe/aluminum structure, varying the PbSe nanoparticle diameter from 1 to 3 nm. In this highly confined regime, we find that the larger particle bandgap can lead to higher open-circuit voltages (~0.6 V), and thus an increase in overall efficiency compared to previously reported devices of this structure. To carry out this study, we modified existing synthesis methods to obtain ultrasmall PbSe nanocrystals with diameters as small as 1 nm, where the nanocrystal size is controlled by adjusting the growth temperature. As expected, we find that photocurrent decreases with size due to reduced absorption and increased recombination, but we also find that the open-circuit voltage begins to decrease for particles with diameters smaller than 2 nm, most likely due to reduced collection efficiency. Owing to this effect, we find peak performance for devices made with PbSe dots with a first exciton energy of ~1.6 eV (2.3 nm diameter), with a typical efficiency of 3.5%, and a champion device efficiency of 4.57%. Comparing the external quantum efficiency of our devices to an optical model reveals that the photocurrent is also strongly affected by the coherent interference in the thin film due to Fabry-Pérot cavity modes within the PbSe layer. Our results demonstrate that even in this simple device architecture, fine-tuning of the nanoparticle size can lead to substantial improvements in efficiency

The SAMI Galaxy Survey: mass-kinematics scaling relations

We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass $M_*$ and the general kinematic parameter $S_K = \sqrt{K V_{rot}^2 + \sigma^2}$ that combines rotation velocity $V_{rot}$ and velocity dispersion $\sigma$. We show that the $\log M_* - \log S_K$ relation: (1)~is linear above limits set by properties of the samples and observations; (2)~has slightly different slope when derived from stellar or gas kinematic measurements; (3)~applies to both early-type and late-type galaxies and has smaller scatter than either the Tully-Fisher relation ($\log M_* - \log V_{rot}$) for late types or the Faber-Jackson relation ($\log M_* - \log\sigma$) for early types; and (4)~has scatter that is only weakly sensitive to the value of $K$, with minimum scatter for $K$ in the range 0.4 and 0.7. We compare $S_K$ to the aperture second moment (the `aperture velocity dispersion') measured from the integrated spectrum within a 3-arcsecond radius aperture ($\sigma_{3^{\prime\prime}}$). We find that while $S_{K}$ and $\sigma_{3^{\prime\prime}}$ are in general tightly correlated, the $\log M_* - \log S_K$ relation has less scatter than the $\log M_* - \log \sigma_{3^{\prime\prime}}$ relation.Comment: 14 pages, 8 figures, Accepted 2019 May 22. Received 2019 May 18; in original form 2019 January

Network analysis of differential Ras isoform mutation effects on intestinal epithelial responses to TNF-α

Tumor necrosis factor alpha (TNF-α) is an inflammatory cytokine that can elicit distinct cellular behaviors under different molecular contexts. Mitogen activated protein kinase (MAPK) pathways, especially the extracellular signal-regulated kinase (Erk) pathway, help to integrate influences from the environmental context, and therefore modulate the phenotypic effect of TNF-α exposure. To test how variations in flux through the Erk pathway modulate TNF-α-elicited phenotypes in a complex physiological environment, we exposed mice with different Ras mutations (K-Ras activation, N-Ras activation, and N-Ras ablation) to TNF-α and observed phenotypic and signaling changes in the intestinal epithelium. Hyperactivation of Mek1, an Erk kinase, was observed in the intestine of mice with K-Ras activation and, surprisingly, in N-Ras null mice. Nevertheless, these similar Mek1 outputs did not give rise to the same phenotype, as N-Ras null intestine was hypersensitive to TNF-α-induced intestinal cell death while K-Ras mutant intestine was not. A systems biology approach applied to sample the network state revealed that the signaling contexts presented by these two Ras isoform mutations were different. Consistent with our experimental data, N-Ras ablation induced a signaling network state that was mathematically predicted to be pro-death, while K-Ras activation did not. Further modeling by constrained Fuzzy Logic (cFL) revealed that N-Ras and K-Ras activate the signaling network with different downstream distributions and dynamics, with N-Ras effects being more transient and diverted more towards PI3K-Akt signaling and K-Ras effects being more sustained and broadly activating many pathways. Our study highlights the necessity to consider both environmental and genomic contexts of signaling pathway activation in dictating phenotypic responses, and demonstrates how modeling can provide insight into complex in vivo biological mechanisms, such as the complex interplay between K-Ras and N-Ras in their downstream effects.National Institute of General Medical Sciences (U.S.) (Grant R01-GM088827)National Cancer Institute (U.S.) (U54-CA112967)United States. Army Research Office (Institute for Collaborative Biotechnologies Grant W911NF-09-D-000

Helping to Support CPC+ Initiative to Integrate Behavioral Health Within Primary Care: A Team-Based Approach to Improving Depression Management

AIM: The objective of this project is to increase the rate of documented successful treatment of depression for both new and established diagnoses of depression at Jefferson Internal Medicine Associates (JIMA) from 29% to 50% over 12 months.https://jdc.jefferson.edu/patientsafetyposters/1027/thumbnail.jp

RNA interference of gonadotropin-inhibitory hormone gene induces arousal in songbirds.

Gonadotropin-inhibitory hormone (GnIH) was originally identified in quail as a hypothalamic neuropeptide inhibitor of pituitary gonadotropin synthesis and release. However, GnIH neuronal fibers do not only terminate in the median eminence to control anterior pituitary function but also extend widely in the brain, suggesting it has multiple roles in the regulation of behavior. To identify the role of GnIH neurons in the regulation of behavior, we investigated the effect of RNA interference (RNAi) of the GnIH gene on the behavior of white-crowned sparrows, a highly social songbird species. Administration of small interfering RNA against GnIH precursor mRNA into the third ventricle of male and female birds reduced resting time, spontaneous production of complex vocalizations, and stimulated brief agonistic vocalizations. GnIH RNAi further enhanced song production of short duration in male birds when they were challenged by playbacks of novel male songs. These behaviors resembled those of breeding birds during territorial defense. The overall results suggest that GnIH gene silencing induces arousal. In addition, the activities of male and female birds were negatively correlated with GnIH mRNA expression in the paraventricular nucleus. Density of GnIH neuronal fibers in the ventral tegmental area was decreased by GnIH RNAi treatment in female birds, and the number of gonadotropin-releasing hormone neurons that received close appositions of GnIH neuronal fiber terminals was negatively correlated with the activity of male birds. In summary, GnIH may decrease arousal level resulting in the inhibition of specific motivated behavior such as in reproductive contexts