Private education and inequality in the knowledge economy

This article explores the consequences of public and private spending on education at all levels, looking at skills and income inequality. We use data for 22 affluent democracies from 1960 or 1995 (depending on data availability) to 2017. High levels of public education spending consistently lower income inequality, both measured as wage dispersion and as the education premium. In contrast, higher levels of private education spending are associated with both higher wage dispersion and a higher education premium. We show that this effect works in part through differential skills acquisition. Public education spending raises the math scores of 15-years old students at the mean and at the 25th percentile, but private education spending has no effect on skills at these levels. We find the same pattern among skills of adults; public education spending raises skills at the 25th percentile and the mean; private spending has no effect. Finally, we also show that higher levels of adult skills indeed depress the education premium

Análise do trabalho cognitivo dos pilotos de helicóptero da aviação offshore na Bacia de Campos

Este trabalho tem como objetivo identificar os fatores contribuintes e os constrangimentos que interferem na atividade dos pilotos que voam na Bacia de Campos a serviço da Petrobras, e cujas consequências afetam o desempenho operacional do sistema de transporte como um todo, bem como a segurança de voo por um lado, e as condições de trabalho dos pilotos, por outro. A pesquisa utiliza a metodologia da análise cognitiva do trabalho, de tradição europeia (Guérin, et al) articulada às recentes abordagens de engenharia cognitiva de sistemas cognitivos desenvolvidas pelos professores David Woods e Erik Hollnagel (Hollnagel & Woods, 2005)

Entrainment and dynamics of ocean-derived impurities within Europa's ice shell

Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Planets 125(10),(2020): e2020JE006394, doi:10.1029/2020JE006394.Compositional heterogeneities within Europa's ice shell likely impact the dynamics and habitability of the ice and subsurface ocean, but the total inventory and distribution of impurities within the shell are unknown. In sea ice on Earth, the thermochemical environment at the ice‐ocean interface governs impurity entrainment into the ice. Here, we simulate Europa's ice‐ocean interface and bound the impurity load (1.053–14.72 g/kg [parts per thousand weight percent, or ppt] bulk ice shell salinity) and bulk salinity profile of the ice shell. We derive constitutive equations that predict ice composition as a function of the ice shell thermal gradient and ocean composition. We show that evolving solidification rates of the ocean and hydrologic features within the shell produce compositional variations (ice bulk salinities of 5–50% of the ocean salinity) that can affect the material properties of the ice. As the shell thickens, less salt is entrained at the ice‐ocean interface, which implies Europa's ice shell is compositionally homogeneous below ~1 km. Conversely, the solidification of water filled fractures or lenses introduces substantial compositional variations within the ice shell, creating gradients in mechanical and thermal properties within the ice shell that could help initiate and sustain geological activity. Our results suggest that ocean materials entrained within Europa's ice shell affect the formation of geologic terrain and that these structures could be confirmed by planned spacecraft observations.This study was supported by the NASA Earth and Space Science Fellowship, grants NNX16AP43H S01 and NNX16AP43H S002. Britney Schmidt was additionally supported by the Europa Clipper Mission. Resources supporting this work were provided by the NASA High‐End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center.2021-03-2

Glutaconate CoA-transferase from Acidaminococcus fermentans: the crystal structure reveals homology with other CoA-transferases

AbstractBackground: Coenzyme A-transferases are a family of enzymes with a diverse substrate specificity and subunit composition. Members of this group of enzymes are found in anaerobic fermenting bacteria, aerobic bacteria and in the mitochondria of humans and other mammals, but so far none have been crystallized. A defect in the human gene encoding succinyl-CoA: 3-oxoacid CoA-transferase causes a metabolic disease which leads to severe ketoacidosis, thus reflecting the importance of this family of enzymes. All CoA-transferases share a common mechanism in which the CoA moiety is transferred from a donor (e.g. acetyl CoA) to an acceptor, (R)-2-hydroxyglutarate, whereby acetate is formed. The transfer has been described by a ping-pong mechanism in which CoA is bound to the active-site residue of the enzyme as a covalent thiol ester intermediate. We describe here the crystal structure of glutaconate CoA-transferase (GCT) from the strictly anaerobic bacterium Acidaminococcus fermentans. This enzyme activates (R)-2-hydroxyglutarate to (R)-2-hydroxyglutaryl-CoA in the pathway of glutamate fermentation. We initiated this project to gain further insight into the function of this enzyme and the structural basis for the characteristics of CoA-transferases.Results: The crystal structure of GCT was solved by multiple isomorphous replacement to 2.55 Å resolution. The enzyme is a heterooctamer and its overall arrangement of subunits can be regarded as an (AB)4tetramer obeying 222 symmetry. Both subunits A and B belong to the open α/β-protein class and can be described as a four-layered α/α/β/α type with a novel composition and connectivity of the secondary structure elements. The core of subunit A consists of seven α/β repeats resulting in an all parallel central β sheet, against which helices pack from both sides. In contrast, the centre of subunit B is formed by a ninefold mixed β sheet. Inboth subunits the helical C terminus is folded back onto the N-terminal domain to form the third layer of helices.Conclusions: The active site of GCT is located at the interface of subunits A and B and is formed by loops of both subunits. The funnel-shaped opening to the active site has a depth and diameter of about 20 Å with the catalytic residue, Glu54 of subunit B, at the bottom. The active-site glutamate residue is stabilized by hydrogen bonds. Despite very low amino acid sequence similarity, subunits A and B reveal a similar overall fold. Large parts of their structures can be spatially superimposed, suggesting that both subunits have evolved from a common ancestor

Focusing a deterministic single-ion beam

We focus down an ion beam consisting of single 40Ca+ ions to a spot size of a few mum using an einzel-lens. Starting from a segmented linear Paul trap, we have implemented a procedure which allows us to deterministically load a predetermined number of ions by using the potential shaping capabilities of our segmented ion trap. For single-ion loading, an efficiency of 96.7(7)% has been achieved. These ions are then deterministically extracted out of the trap and focused down to a 1sigma-spot radius of (4.6 \pm 1.3)mum at a distance of 257mm from the trap center. Compared to former measurements without ion optics, the einzel-lens is focusing down the single-ion beam by a factor of 12. Due to the small beam divergence and narrow velocity distribution of our ion source, chromatic and spherical aberration at the einzel-lens is vastly reduced, presenting a promising starting point for focusing single ions on their way to a substrate.Comment: 16 pages, 7 figure

A question by Chihara about shell polynomials and indeterminate moment problems

The generalized Stieltjes--Wigert polynomials depending on parameters 0\le p<1 and 0<q<1 are discussed. By removing the mass at zero of the N-extremal solution concentrated in the zeros of the D-function from the Nevanlinna parametrization, we obtain a discrete measure \mu^M which is uniquely determined by its moments. We calculate the coefficients of the corresponding orthonormal polynomials (P^M_n). As noticed by Chihara, these polynomials are the shell polynomials corresponding to the maximal parameter sequence for a certain chain sequence. We also find the minimal parameter sequence, as well as the parameter sequence corresponding to the generalized Stieltjes--Wigert polynomials, and compute the value of related continued fractions. The mass points of \mu^M have been studied in recent papers of Hayman, Ismail--Zhang and Huber. In the special case of p=q, the maximal parameter sequence is constant and the determination of \mu^M and (P^M_n) gives an answer to a question posed by Chihara in 200

Assessment Team Decision-Making: One Way to Assess the Multi-Criteria Decision-Making Based on Observation.

Decision-making has been a subject actively investigated in several areas of knowledge such as Philosophy, Economics, Psychology, Computer Science, among others. This paper explores the potential opportunities offered by two methodologies to assess the team decision-making at the end of a simulated exercise (training). We present a case study showing how to measure the team decision-making combining both methodologies to assess a team of three experienced Officers from the Military Fire Brigade of the State of Rio de Janeiro. The simulated exercise was carried out within the Integrated Center of Command and Control of Rio de Janeiro. We intend this study provide a pathway that can be helpful in reducing the subjectivity generated during the observation of the team decision-making in Emergency Management environments