The Renormalization-Group Method Applied to Asymptotic Analysis of Vector Fields

The renormalization group method of Goldenfeld, Oono and their collaborators is applied to asymptotic analysis of vector fields. The method is formulated on the basis of the theory of envelopes, as was done for scalar fields. This formulation actually completes the discussion of the previous work for scalar equations. It is shown in a generic way that the method applied to equations with a bifurcation leads to the Landau-Stuart and the (time-dependent) Ginzburg-Landau equations. It is confirmed that this method is actually a powerful theory for the reduction of the dynamics as the reductive perturbation method is. Some examples for ordinary diferential equations, such as the forced Duffing, the Lotka-Volterra and the Lorenz equations, are worked out in this method: The time evolution of the solution of the Lotka-Volterra equation is explicitly given, while the center manifolds of the Lorenz equation are constructed in a simple way in the RG method.Comment: The revised version of RYUTHP 96/1. Submitted to Prog. Theor. Phys. (Kyoto) in Feb., 1996. 28 pages. LATEX. No figure

Paid Sick Leave: Should Investing in the Workforce be Mandatory?

Paid sick leave is a benefit supplied to employees: it means that they are allotted a certain amount of days every year when they can call in sick and the employer still pays them for a full day of work. Roughly 86% of U.S. workers currently receive at least some paid sick leave as a benefit from their employers. While workers at larger businesses have more paid leave than workers at smaller firms, in every sector of the economy the vast majority of workers get paid sick leave. Most policies only cover illnesses of the employee herself. Employees who have families who are sick cannot use their paid time off. Many people are forced to choose between their family’s health and a paycheck. While the federal Family and Medical Leave Act (FMLA) requires employers with more than fifty employees to provide up to twelve weeks of time off when a worker, or an immediate family member, has a serious illness or recently gave birth to a child, this time is unpaid. Most employees cannot afford to forgo their paychecks for this length of time

The 2008 federal intervention to stabilize Fannie Mae and Freddie Mac

Fannie Mae and Freddie Mac are government-sponsored enterprises that play a central role in U.S. residential mortgage markets. In recent years, policymakers became increasingly concerned about the size and risk-taking incentives of these two institutions. In September 2008, the federal government intervened to stabilize Fannie Mae and Freddie Mac in an effort to ensure the reliability of residential mortgage finance in the wake of the subprime mortgage crisis. This paper describes the sources of financial distress at Fannie Mae and Freddie Mac, outlines the measures taken by the federal government, and presents some evidence about the effectiveness of these actions. Looking ahead, policymakers will need to consider the future of Fannie Mae and Freddie Mac as well as the appropriate scope of public sector activities in primary and secondary mortgage markets.Government-sponsored enterprises ; Mortgage loans

Federal Home Loan Bank mortgage purchases: Implications for mortgage markets

The Federal Home Loan Bank (FHLB) System is a government-sponsored enterprise created by Congress to support residential housing finance. Historically, the twelve regional wholesale banks that constitute the FHLB System have pursued this goal by making loans to their depository institution members secured by residential mortgage loans. In 1997, however, the Federal Home Loan Bank of Chicago began purchasing pools of conforming mortgages under its Mortgage Partnership Finance Program. Today, nine FHLBs offer this program, and the remaining three offer their own Mortgage Purchase Programs. ; The FHLB mortgage programs represent a small but growing part of the secondary conforming mortgage market, which has traditionally been dominated by the Federal National Mortgage Association (Fannie Mae) and the Federal Home Loan Mortgage Corporation (Freddie Mac). This article examines the various FHLB mortgage programs offered, analyzes the evolving competitive environment in the secondary conforming mortgage market, and identifies implications for this market. ; Consumers could ultimately benefit from lower mortgage costs because of a lower cost of guaranteeing mortgage credit, the author contends, but the savings per borrower would likely be small. He also notes that increased competition may reduce the franchise value of Fannie Mae and Freddie Mac, in turn possibly increasing risk-taking incentives for these firms. The author concludes that the evolution of this competitive landscape bears close attention as it could have important implications for mortgage markets.Federal home loan banks ; Mortgage loans

Fannie Mae's and Freddie Mac's voluntary initiatives: Lessons from banking

The federal government has an interest in the financial stability of Fannie Mae and Freddie Mac because of their importance to financial markets and the government's implicit guarantee of their liabilities. ; In October 2000 these two housing government-sponsored enterprises (GSEs) announced six voluntary initiatives. One initiative would enhance market discipline by having the GSEs issue subordinated debt. A second would boost liquidity by having the GSEs maintain a liquid securities portfolio. The other four initiatives would increase transparency by having the GSEs disclose their credit and interest rate losses under certain scenarios, obtain a credit rating for the government's exposure to loss, and disclose whether the GSEs comply with certain capital adequacy standards. ; This article evaluates the initiatives from the perspective of current banking standards. The analysis suggests that the initiatives are beneficial but could be made more effective. The authors point out that the contribution of the subordinated debt initiative depends largely on whether investors believe the implicit guarantee extends to subordinated debtholders. The need for the liquidity initiative has not been established, the authors conclude, and can be criticized as allowing the GSEs to earn a credit spread. The most important of the disclosure initiatives, the one for interest rate risk, will provide some new information but could be more informative if it summarized a wider set of interest rate scenarios.Government-sponsored enterprises ; Federal Home Loan Mortgage Corporation ; Federal National Mortgage Association ; Federal home loan banks

Modelling micropolar behaviour in cortical bone

This presentation looks at modelling micropolar behaviour in cortical bon

Haversian canal structures can be associated with size effects in cortical bone

Prediction of periprosthetic failure may be improved by an improved model of bone elasticity which includes microstructural information. Micropolar theory facilitates such information to be included in a continuum model. We assessed the extent of bone’s micropolar behaviour in bending both numerically and experimentally. The numerical model was consistent with micropolar behaviour, and experimental results exhibited size effects that may have been confounded by surface roughness effects, as predicted numerically

Empirical studies of financial innovation: lots of talk, little action?

This paper reviews the extant empirical studies of financial innovation. Adopting broad criteria, the authors found just two dozen studies, over half of which (fourteen) had been conducted since 2000. Since some financial innovations are examined by more than one study, only fourteen distinct phenomena have been covered. Especially striking is the fact that only two studies are directed at the hypotheses advanced in many broad descriptive articles concerning the environmental conditions (e.g., regulation, taxes, unstable macroeconomic conditions, and ripe technologies) spurring financial innovation. The authors offer some tentative conjectures as to why empirical studies of financial innovation are comparatively rare. Among their suggested culprits is an absence of accessible data. The authors urge financial regulators to undertake more surveys of financial innovation and to make the survey data more available to researchers.Financial modernization ; Banks and banking ; Patents ; Securities