An unusually rapid Claisen rearrangement involving ring expansion

A Claisen rearrangement of a partially-fluorinated system involving ring expansion occurred at an unusually low temperature, 100 degreesC lower than a comparable system from the literature

The rise and fall of subprime mortgages

After booming the first half of this decade, U.S. housing activity has retrenched sharply. Single-family building permits have plunged 52 percent and existing-home sales have declined 30 percent since their September 2005 peaks. ; A rise in mortgage interest rates that began in the summer of 2005 contributed to the housing market's initial weakness. By late 2006, though, some signs pointed to renewed stability. They proved short-lived as loan-quality problems sparked a tightening of credit standards on mortgages, particularly for newer and riskier products. As lenders cut back, housing activity began to falter again in spring 2007, accompanied by additional rises in delinquencies and foreclosures. Late-summer financial-market turmoil prompted further toughening of mortgage credit standards. ; The recent boom-to-bust housing cycle raises important questions. Why did it occur, and what role did subprime lending play? How is the retrenchment in lending activity affecting housing markets, and will it end soon? Is the housing slowdown spilling over into the broader economy?Housing - Finance ; Mortgages ; Mortgage loans

Made in Texas: the natural selection of manufacturing

Manufactures - Texas

The fallacy of a pain-free path to a healthy housing market

In the mid-1990s, the public policy goal of increasing the U.S. homeownership rate collided with a huge leap in financial innovation. Lenders shifted from originating and holding mortgages to originating and packaging them for sale to investors. These new financial products enabled millions of Americans who hadn’t previously qualified to buy a home to become owners. Housing construction boomed, reaching a postwar high—9.1 million homes were built between 2002 and 2006, a period when 5.6 million U.S. households were formed. ; The resulting oversupply of homes presents policymakers with a formidable challenge as they struggle to craft a sustainable economic recovery. Usually a driver of economic recoveries, the housing market is foundering as an engine of growth. ; Generations of policymakers since the 1930s have sought to increase the homeownership rate. By the late 1960s, it had reached 64.3 percent of households, remaining there through the mid-1990s, in apparent equilibrium with household formation during a period of sustained U.S. economic growth. A fresh push to increase ownership drove the rate up 5 percentage points to its peak in the mid-2000s. Home price gains followed the rate upward.Mortgage loans ; Construction industry ; Housing - Prices

Assembly of objects with not fully predefined shapes

An assembly problem in a non-deterministic environment, i.e., where parts to be assembled have unknown shape, size and location, is described. The only knowledge used by the robot to perform the assembly operation is given by a connectivity rule and geometrical constraints concerning parts. Once a set of geometrical features of parts has been extracted by a vision system, applying such a rule allows the dtermination of the composition sequence. A suitable sensory apparatus allows the control the whole operation

Peer-based query rewriting in SPARQL for semantic integration of linked data

In this proposal we address the problem of ontology-based SPARQL query answering over distributed Linked Data sources, where the ontology is given by conjunctive mappings between the source schemas in a peer-to-peer fashion and by equality constraints between constants. In our setting, the data is not materialised in a single datastore: it is accessed in a distributed environment through SPARQL endpoints. We aim to achieve query answering by generating the perfect rewriting of the original query and then processing the rewritten query over distributed SPARQL endpoints. We identify a subset of ontology constraints that enjoy the first-order rewritability property and we perform preliminary empirical evaluation taking into account such restricted constraints only. For future work, we aim to tackle the query answering problem in the general case

Fed policy in the financial crisis: arresting the adverse feedback loop

An adverse feedback loop takes hold when a weakening financial system and a slowing economy feed off each other. A crisis or shock curtails lending, hobbling the real economy; the more production and employment falter, the more lending contracts. ; Arresting the adverse feedback loop could prove to be the seminal challenge of early 21st century monetary policymaking. Since sounding the alarm in January 2008, the Fed has taken a series of actions--many unprecedented--to prevent additional damage to financial markets and restore lending activity. These policies have had some success in loosening the grip of the adverse feedback loop and may have finally positioned the economy for growth. Still, doubts linger. The risk remains that the actions may prove insufficient to put the economy on a clear path to rising employment and stable prices.Financial markets ; Federal Reserve System ; Monetary policy ; Financial crises - United States