26,463 research outputs found
Bouncing Cosmologies: Progress and Problems
We review the status of bouncing cosmologies as alternatives to cosmological
inflation for providing a description of the very early universe, and a source
for the cosmological perturbations which are observed today. We focus on the
motivation for considering bouncing cosmologies, the origin of fluctuations in
these models, and the challenges which various implementations face.Comment: 30 pages, 6 figures; references adde
The Economic Benefits of Closing Educational Achievement Gaps: Promoting Growth and Strengthening the Nation by Improving the Educational Outcomes of Children of Color
This report quantifies the economic benefits of closing one of the most harmful racial and ethnic gaps: the educational achievement gap that exists between black and Hispanic children and native-born white children. Gaps in academic achievement are a function of a host of factors, such as income and wealth inequality, access to child care and preschool programs, nutrition, physical and emotional health, environmental factors, community and family structures,differences in the quality of instruction and school, and educational attainment. This suggests there are a wide range of public policies that could help narrow educational achievement gaps; this report demonstrates that there are enormous payoffs to closing the gaps through public policies. It also outlines effective public policy strategies to achieve this goal, though their details are left to future research. After briefly summarizing the analysis's findings, this report places the educational achievement gaps in context to help explain their significance and the reasons they exist. In particular, the report reviews data on growing inequality, demographic changes, and intensifying global economic competition. This clarifies the need to address educational achievement gaps and helps explain why the benefits of closing gaps are great. The report then describes factors that cause educational achievement gaps and offers public policies that could help close them. The subsequent sections of the report discuss the literature on the importance of academic achievement to economic growth, the methodology used in the analysis, and its detailed findings
‘A devotion to the experimental sciences and arts’: the subscription to the great battery at the Royal Institution 1808–9
A significant but neglected theme in the history of British science in the nineteenth century is the funding of institutional research. The subscription to the ‘great battery’ at the Royal Institution in 1808 and 1809 provides the first instance of named individuals prepared to commit themselves to the provision of apparatus to be used for research in the new field of electrochemistry. This paper analyses the subscribers who were deemed to be ‘enlightened’ and whom Humphry Davy subsequently described as ‘a few zealous cultivators and patrons of science’. Using information from the subscription list, a distinction is made between the individual subscriptions pledged and the sums actually paid. In contextualizing the subscription, insights are provided into the Royal Society, the contemporary scientific community and the politics of metropolitan science. The voltaic subscription represents an early example of the repercussions of the nature of research funding for institutional finances and governance
Will The Real Family-Friendly Employer Please Stand Up: Who Permits Parents To Reduce Working Hours For Purposes of Childcare?
Balancing work and family life can be a challenge, especially when a person needs to adjust her work schedule to deal with a family crisis. If the crisis involves a long term problem, such as caring for a sick or injured child that requires several months of care, the balancing act can require major shifts in the role an employee plays in a firm. This paper examines how an employer reacts to such a family-work issue: an employee who want to move from full-time to part-time in order to care for a young child. Most empirical work in this area deals with formal policies such as maternity leave, paternity leave, or leave beyond that required by the Family and Medical Leave Act and maps the type of formal policies a firm has into some "family-friendly" index. Switching from full-time to part-time is usually an informal process and it is not obvious how a firm ranking high on an index based of formal "family-friendly" policies would respond to such a request. Indeed, organizations with codified formal policies may be precisely the kinds of employers who do not permit such a shift from full-time to part-time. This is in fact what we find. Larger organizations are much more likely to provide formal policies such as paid maternity and paternity leave, while establishments that are not part of larger organizations are more likely to permit an employee to shift to part-time in order to care for a young child. These results suggests that family-friendly indexes that are based on formal policies may be unfairly labelling smaller firms "unfriendly" towards families simply because they use informal approaches to deal with family crises.
Racial Sorting and Neighborhood Quality
In cities throughout the United States, blacks tend to live in significantly poorer and lower-amenity neighborhoods than whites. An obvious first-order explanation for this is that an individual%u2019%u2019s race is strongly correlated with socioeconomic status (SES), and poorer households can only afford lower quality neighborhoods. This paper conjectures that another explanation may be as important. The limited supply of high-SES black neighborhoods in most U.S. metropolitan areas means that neighborhood race and neighborhood quality are explicitly bundled together. In the presence of any form of segregating preferences, this bundling raises the implicit price of neighborhood amenities for blacks relative to whites, prompting our conjecture -- that racial differences in the consumption of neighborhood amenities are significantly exacerbated by sorting on the basis of race, given the small numbers of blacks and especially high-SES blacks in many cities. To provide evidence on this conjecture, we estimate an equilibrium sorting model with detailed restricted Census microdata and use it to carry out informative counterfactual simulations. Results from these indicate that racial sorting explains a substantial portion of the gap between whites and blacks in the consumption of a wide range of neighborhood amenities -- in fact, as much as underlying socioeconomic differences across race. We also show that the adverse effects of racial sorting for blacks are fundamentally related to the small proportion of blacks in the U.S. metropolitan population. These results emphasize the significant role of racial sorting in the inter-generational persistence of racial differences in education, income, and wealth.
Credibility and Monetary Policy
A highly credible monetary policy helps to reduce the degree of uncertainty that can surround the objectives of such policy. When the monetary policy pursued by the central bank is credible, the expectations of the public are focused on a target. If the public believes that the Bank will act to bring inflation back to the target, then its expectations will not react so strongly to fluctuating price trends. In turn, fluctuations in inflation, interest rates, output, and employment should be less pronounced than in the absence of such credibility. The adoption of inflation control as a monetary policy objective by some countries has led central banks to take steps to enhance the credibility of monetary policy. For the Bank of Canada, these include the publication of our Monetary Policy Report each May and November, with formal updates each February and August the initiation of communications activities across the country the use of the overnight interest rate as a short-term operating target the issuing of a press release each time the Bank changes its key rates. To date, most of the studies on this topic have concluded that success in keeping inflation within a target range has helped to increase the credibility of Canadian monetary policy. These surveys suggest that expected inflation, which stood at about 5 per cent in 1990, declined to around 2 per cent by 1999 (Chart 1, page 15). Indeed, according to these surveys, for the entire period during which the Bank has had a target range for inflation, expected inflation rates have remained within that range. Inflation expectations have also reacted very little to changes in the total CPI, suggesting that the targets have helped to focus expectations on the target rate and have thus enhanced the credibility of monetary policy (Chart 2, page 16). One particular study shows that the life of collective wage agreements in Canada has been increasing and that the number of such agreements containing cost-of-living adjustment (COLA) clauses has steadily declined. The authors of this study suggest that this may reflect the greater credibility of Canadian monetary policy (Table 1, page 16). The proportion of mortgages with five-year terms is now higher than it was in the mid-1980s, and many financial institutions have been offering 7-to 10-year mortgages. This also suggests that inflation targets have gained credibility.
Quantitative Anderson localization of Schr\"odinger eigenstates under disorder potentials
This paper concerns spectral properties of linear Schr\"odinger operators
under oscillatory high-amplitude potentials on bounded domains. Depending on
the degree of disorder, we prove the existence of spectral gaps amongst the
lowermost eigenvalues and the emergence of exponentially localized states. We
quantify the rate of decay in terms of geometric parameters that characterize
the potential. The proofs are based on the convergence theory of iterative
solvers for eigenvalue problems and their optimal local preconditioning by
domain decomposition.Comment: accepted for publication in M3A
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