“Undemocracy”: inequalities in science Xie, Yu
Science (American Association for the Advancement of Science),
05/2014, Letnik:
344, Številka:
6186
Journal Article
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Inequality, an intrinsic feature of science, has trended upward in recent years
In recent years, academic scholarship and public discourse have become increasingly preoccupied with social and ...economic inequality, which has risen in many countries. It is surprising that more attention has not been paid to the large, changing inequalities in the world of scientific research. I suggest that although the basic structure of inequalities in science has remained unchanged, their intensities and mechanisms may have been altered by recent forces of globalization and internet technology.
Population heterogeneity is ubiquitous in social science. The very objective of social science research is not to discover abstract and universal laws but to understand population heterogeneity. Due ...to population heterogeneity, causal inference with observational data in social science is impossible without strong assumptions. Researchers have long been concerned with two potential sources of bias. The first is bias in unobserved pretreatment factors affecting the outcome even in the absence of treatment. The second is bias due to heterogeneity in treatment effects. In this article, I show how “composition bias” due to population heterogeneity evolves over time when treatment propensity is systematically associated with heterogeneous treatment effects. A form of selection bias, composition bias, arises dynamically at the aggregate level even when the classic assumption of ignorability holds true at the microlevel.
Income inequality in today’s China Xie, Yu; Zhou, Xiang
Proceedings of the National Academy of Sciences - PNAS,
05/2014, Letnik:
111, Številka:
19
Journal Article
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Using multiple data sources, we establish that China's income inequality since 2005 has reached very high levels, with the Gini coefficient in the range of 0.53–0.55. Analyzing comparable survey data ...collected in 2010 in China and the United States, we examine social determinants that help explain China’s high income inequality. Our results indicate that a substantial part of China’s high income inequality is due to regional disparities and the rural-urban gap. The contributions of these two structural forces are particularly strong in China, but they play a negligible role in generating the overall income inequality in the United States, where individual-level and family-level income determinants, such as family structure and race/ethnicity, play a much larger role.
The superior academic achievement of Asian Americans is a well-documented phenomenon that lacks a widely accepted explanation. Asian Americans’ advantage in this respect has been attributed to three ...groups of factors: (i) socio-demographic characteristics, (ii) cognitive ability, and (iii) academic effort as measured by characteristics such as attentiveness and work ethic. We combine data from two nationally representative cohort longitudinal surveys to compare Asian-American and white students in their educational trajectories from kindergarten through high school. We find that the Asian-American educational advantage is attributable mainly to Asian students exerting greater academic effort and not to advantages in tested cognitive abilities or socio-demographics. We test explanations for the Asian–white gap in academic effort and find that the gap can be further attributed to (i) cultural differences in beliefs regarding the connection between effort and achievement and (ii) immigration status. Finally, we highlight the potential psychological and social costs associated with Asian-American achievement success.
Despite widespread distribution of LAMP1 and the heterogeneous nature of LAMP1-labeled compartments, LAMP1 is routinely used as a lysosomal marker, and LAMP1-positive organelles are often referred to ...as lysosomes. In this study, we use immunoelectron microscopy and confocal imaging to provide quantitative analysis of LAMP1 distribution in various autophagic and endolysosomal organelles in neurons. Our study demonstrates that a significant portion of LAMP1-labeled organelles do not contain detectable lysosomal hydrolases including cathepsins D and B and glucocerebrosidase. A bovine serum albumin-gold pulse-chase assay followed by ultrastructural analysis suggests a heterogeneity of degradative capacity in LAMP1-labeled endolysosomal organelles. Gradient fractionation displays differential distribution patterns of LAMP1/2 and cathepsins D/B in neurons. We further reveal that LAMP1 intensity in familial amyotrophic lateral sclerosis-linked motor neurons does not necessarily reflect lysosomal deficits in vivo. Our study suggests that labeling a set of lysosomal hydrolases combined with various endolysosomal markers would be more accurate than simply relying on LAMP1/2 staining to assess neuronal lysosome distribution, trafficking, and functionality under physiological and pathological conditions.
Who benefits most from college? Brand, Jennie E; Xie, Yu
American sociological review,
04/2010, Letnik:
75, Številka:
2
Journal Article
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In this article, we consider how the economic return to a college education varies across members of the U.S. population. Based on principles of comparative advantage, scholars commonly presume that ...positive selection is at work, that is, individuals who are most likely to select into college also benefit most from college. Net of observed economic and noneconomic factors influencing college attendance, we conjecture that individuals who are least likely to obtain a college education benefit the most from college. We call this theory the negative selection hypothesis. To adjudicate between the two hypotheses, we study the effects of completing college on earnings by propensity score strata using an innovative hierarchical linear model with data from the National Longitudinal Survey of Youth 1979 and the Wisconsin Longitudinal Study. For both cohorts, for both men and women, and for every observed stage of the life course, we find evidence suggesting negative selection. Results from auxiliary analyses lend further support to the negative selection hypothesis.
The recent theory-orientated discovery of record high-temperature superconductivity (Tc∼250 K) in sodalitelike clathrate LaH10 is an important advance toward room-temperature superconductors. Here, ...we identify an alternative clathrate structure in ternary Li2MgH16 with a remarkably high estimated Tc of ∼473 K at 250 GPa, which may allow us to obtain room-temperature or even higher-temperature superconductivity. The ternary compound mimics a Li- or electron-doped binary hydride of MgH16. The parent hydride contains H2 molecules and is not a good superconductor. The extra electrons introduced break up the H2 molecules, increasing the amount of atomic hydrogen compared with the parent hydride, which is necessary for stabilizing the clathrate structure or other high-Tc structures. Our results provide a viable strategy for tuning the superconductivity of hydrogen-rich hydrides by donating electrons to hydrides via metal doping. Our approach may pave the way for finding high-Tc superconductors in a variety of ternary or quaternary hydrides.
Using population intercensus and national survey data, we examine marriage timing in urban China spanning the past six decades. Descriptive analysis from the intercensus shows that marriage patterns ...have changed in China. Marriage age is delayed for both men and women, and prevalence of nonmarriage became as high as one-quarter for men in recent birth cohorts with very low levels of education. Capitalizing on individual-level survey data, we further explore the effects of demographic and socioeconomic determinants of entry into marriage in urban China over time. Our study yields three significant findings. First, the influence of economic prospects on marriage entry has significantly increased during the economic reform era for men. Second, the positive effect of working in the state-owned sector has substantially weakened. Third, educational attainment now has a negative effect on marriage timing for women. Taken together, these results suggest that the traditional hypergamy norm has persisted in China as an additional factor in the influences of economic resources on marriage formation.
We report to use the main protease (M
) of SARS-Cov-2 to screen plant flavan-3-ols and proanthocyanidins. Twelve compounds, (-)-afzelechin (AF), (-)-epiafzelechin (EAF), (+)-catechin (CA), ...(-)-epicatechin (EC), (+)-gallocatechin (GC), (-)-epigallocatechin (EGC), (+)-catechin-3-O-gallate (CAG), (-)-epicatechin-3-O-gallate (ECG), (-)-gallocatechin-3-O-gallate (GCG), (-)-epigallocatechin-3-O-gallate (EGCG), procyanidin A2 (PA2), and procyanidin B2 (PB2), were selected for docking simulation. The resulting data predicted that all 12 metabolites could bind to M
. The affinity scores of PA2 and PB2 were predicted to be -9.2, followed by ECG, GCG, EGCG, and CAG, -8.3 to -8.7, and then six flavan-3-ol aglycones, -7.0 to -7.7. Docking characterization predicted that these compounds bound to three or four subsites (S1, S1', S2, and S4) in the binding pocket of M
via different spatial ways and various formation of one to four hydrogen bonds.
analysis with 10 available compounds showed that CAG, ECG, GCG, EGCG, and PB2 inhibited the M
activity with an IC
value, 2.98 ± 0.21, 5.21 ± 0.5, 6.38 ± 0.5, 7.51 ± 0.21, and 75.3 ± 1.29 μM, respectively, while CA, EC, EGC, GC, and PA2 did not have inhibitory activities. To further substantiate the inhibitory activities, extracts prepared from green tea (GT), two muscadine grapes (MG), cacao, and dark chocolate (DC), which are rich in CAG, ECG, GAG, EGCG, or/and PB2, were used for inhibitory assay. The resulting data showed that GT, two MG, cacao, and DC extracts inhibited the M
activity with an IC
value, 2.84 ± 0.25, 29.54 ± 0.41, 29.93 ± 0.83, 153.3 ± 47.3, and 256.39 ± 66.3 μg/ml, respectively. These findings indicate that on the one hand, the structural features of flavan-3-ols are closely associated with the affinity scores; on the other hand, the galloylation and oligomeric types of flavan-3-ols are critical in creating the inhibitory activity against the M
activity.
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