24,206 research outputs found
Currents and Superpotentials in classical gauge theories: II. Global aspects and the example of Affine gravity
The conserved charges associated with gauge symmetries are defined at a boundary component of spacetime because the corresponding Noether current can be rewritten on-shell as the divergence of a superpotential. However, the latter is afflicted by ambiguities. Regge and Teitelboim found a procedure to lift the arbitrariness in the Hamiltonian framework. An alternative covariant formula was proposed by one of us for an arbitrary variation of the superpotential, it depends only on the equations of motion and on the gauge symmetry under consideration. Here we emphasize that in order to compute the charges, it is enough to stay at a boundary of spacetime, without requiring any hypothesis about the bulk or about other boundary components, so one may speak of holographic charges. It is well known that the asymptotic symmetries that lead to conserved charges are really defined at infinity, but the choice of boundary conditions and surface terms in the action and in the charges is usually determined through integration by parts, whereas each component of the boundary should be considered separately. We treat the example of gravity (for any spacetime dimension, with or without cosmological constant), formulated as an affine theory which is a natural generalization of the Palatini and Cartan-Weyl (vielbein) first-order formulations. We then show that the superpotential associated with a Dirichlet boundary condition on the metric (the one needed to treat asymptotically flat or AdS spacetimes) is the one proposed by Katz et al and not that of Komar. We finally discuss the KBL superpotential at null infinity
"Macroeconomic Imbalances in the United States and Their Impact on the International Financial System"
The argument put forward in this paper is twofold. First, the financial crisis of 2007-08 was made global by the current account deficit in the United States; and second, there is global dependence on the United States trade deficit as a means of maintaining liquidity in financial markets. The outflow of dollars from the United States was invested in U.S. capital markets, causing inflation in asset markets and leading to a bubble and bust in the subprime mortgage sector. Since the U.S. dollar is the international reserve currency, international debt is mostly denominated in dollars. Because there is a high degree of global financial integration, any reduction in the U.S. balance of trade will have negative effects on many countries throughout the world--for example, those countries dependent on exporting to the United States in order to finance their debt.
Identity theft: a pernicious and costly fraud
On October 3, 2003, the Payment Cards Center of the Federal Reserve Bank of Philadelphia sponsored a workshop on identity theft to examine its growing impact on participants in our payments system. Avivah Litan, vice president and research director of financial services for Gartner Inc., led the workshop. The discussion began and this paper follows with a broad study of identity theft, at times compared with traditional payment fraud, and continues with an evaluation of its overall risk to consumers, merchants, and credit providers. The paper compares the incentives each such party has to address identity theft in concert with current market response to the crime. Finally, the paper concludes by posing several questions for further study. This paper supplements material from Litanâs presentation with additional research on the crime of identity theft.Fraud ; Identity theft
Identity Salience and Involvement among Resident and Nonresident Fathers
The literature on father involvement suggests that the value men ascribe to the father role is important for understanding their involvement with their children, yet this theory has received only limited empirical attention. Using data from the Fragile Families and Child Wellbeing Study (N = 3,554), I examined the association between fathers? identity salience reported at their child?s birth and their involvement (accessibility, engagement, and responsibility) when their child was about 1, 3, and 5 years old, carefully considering the role played by fathers? residence status. I found that fathers? identity salience predicted future levels of engagement net of a large number of fathers? characteristics, and that fathers with high identity salience were more likely to reside with their child, which facilitated their involvement. These results suggest that programs designed to enhance the salience of the father role would be useful for teaching men to become more involved fathers.Fatherhood, Fragile Families and Child Wellbeing (FFCW), Longitudinal Data, Parental Involvement, Social Psychology (Family)
Supply- and demand-side developments influencing growth in the debit market
On August 3, 2006, the Payment Cards Center of the Federal Reserve Bank of Philadelphia hosted a workshop led by Ronald Congemi, senior vice president of strategic industry relations for First Data Corporation, to examine developments on both the supply side and demand side that are influencing growth in the debit card market. On the supply side, Congemi addressed banksâ increasing recognition of the importance of payments-related revenues in their institutional profit and loss statements, the effect of differences in interchange fees between PIN and signature debit, and the greater focus on cost structures for debit card issuers. On the demand side, he considered how changes in consumer payment preferences and innovations in the debit market were influencing consumer behavior and payment choice and, ultimately, competition among payment alternatives.Debit cards
The epidemiology of acute encephalitis.
Encephalitis means inflammation of the brain matter. Despite being a rare condition, encephalitis is of public health importance worldwide because it has high morbidity and mortality. Yet, many details about its epidemiology have yet to be elucidated. This review attempts to summarise what is known about the epidemiology of the infective causes of encephalitis and is based on a literature search of the Medline archives. Infection is the most common cause identified, with viruses being the most important known aetiological agents. Incidence varies between studies but is generally between 3.5 and 7.4 per 100,000 patient-years. Encephalitis affects peoples of all ages; however, incidence is higher in the paediatric population. Although both sexes are affected, most studies have shown a slight predominance in males. Encephalitis occurs worldwide; some aetiologies have a global distribution (herpesviruses) while others are geographically restricted (arboviruses). Although definite epidemiological trends are evident, it is difficult to make generalisations as few population-based studies exist, most cases are not reported to health authorities, and many possible pathogens are implicated but in most cases a cause is never found. A better understanding of the epidemiology of this devastating disease will pave the way for better prevention and control strategies
Heartland Payment Systems: lessons learned from a data breach
On August 13, 2009, the Payment Cards Center hosted a workshop examining the changing nature of data security in consumer electronic payments. The center invited the chairman and CEO of Heartland Payment Systems (HPS or Heartland), Robert (Bob) Carr, to lead this discussion and to share his experiences stemming from the data breach at his company in late 2008 and, as important, to discuss lessons learned as a result of this event. The former director of the Payment Cards Center, Peter Burns, who is acting as a senior payments advisor to HPS, also joined the discussion to outline Heartland's post-breach efforts aimed at improving information sharing and data security within the consumer payments industry. In conclusion, Carr introduced several technology solutions that are under discussion in payment security circles as ways to better secure payment card data as they move among the different parties in the card payment systems: end-to-end encryption, tokenization, and chip technology. While HPS has been very supportive of end-to-end encryption, each of these alternatives offers its own set of advantages and disadvantages.Payment systems ; Data protection ; Electronic commerce
Prepaid card models: a study in diversity
Summary: On January 13, 2005, the Payment Cards Center of the Federal Reserve Bank of Philadelphia sponsored a workshop led by Gary Palmer, chief operating officer and co-founder of WildCard Systems, to examine the developing market for prepaid card products. Palmer described several distinct types of prepaid card value propositions, each with its own set of operational needs and customer servicing requirements. In addition, Palmer described new roles that exist in prepaid card programs that are not present in traditional credit and debit card programs. He emphasized that the variety of these programsâ requirements and the breadth of third party participants create complexities not only in the servicing of these accounts but also in the economics of these programs and the regulation of this payments category.Stored-value cards
The role of electronic payments in disaster recovery: providing more than convenience
On May 3-4, 2006, the Payment Cards Center hosted a two-day conference titled âThe Role of Electronic Payments in Disaster Recovery: Providing More Than Convenience.â The event brought together participants from a range of groups, including financial institutions and other financial service providers; federal and state government and national relief agencies; and the bank regulatory community. Participants examined the lessons learned from Hurricane Katrina and considered how these experiences may be useful in identifying opportunities to further strengthen the financial systemâs response to future catastrophic events.Disaster relief
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