Modeling U.S. monetary policy during the global financial crisis and lessons for Covid-19.

The paper formulates the modeling of unconventional monetary policy and critically evaluates its effectiveness to address the Global Financial Crisis. We begin with certain principles guiding general scientific modeling and focus on Milton Friedman's 1968 Presidential Address that delineates the strengths and limitations of monetary policy to pursue certain goals. The modeling of monetary policy with its novelty of quantitative easing to target unusually high unemployment is evaluated by a Markov switching econometric model using monthly data for the period 2002-2015. We conclude by relating the lessons learned from unconventional monetary policy during the Global Financial Crisis to the recent bold initiatives of the Fed to mitigate the economic and financial impact of the Covid-19 pandemic on U.S. households and businesses.

Direct observation of odd-even effect in dilute polymeric solutions: A time-resolved fluorescence anisotropy study.

The odd-even effect is demonstrated, for the first time, in dilute polymeric solutions of polyethers, consisting of substituted luminescent quinquephenyl units which are connected by flexible aliphatic chains of 7-12 methylene groups. The effect, which is demonstrated by means of steady state and time resolved fluorescence anisotropy, has been attributed to the different mutual orientation of the luminescent dipoles, in the odd (7, 9, 11) and even (8, 10, 12) polymers. Namely, as the temperature of the solution is lowered the flexible aliphatic chains adopt the nearly all-staggered lowest energy conformation, which results in different mutual orientations of the fluorophores in the two types of polymers.

Dummy measurement of chest injuries induced by two-point shoulder belts.

The University of Miami's William Lehman Injury Research Center at the Jackson Memorial Medical Center conducts interdisciplinary investigations to study seriously injured restrained occupants in frontal automobile collisions. Engineering analysis of these crashes is conducted in conjunction with the National Crash Analysis Center at the George Washington University. The multidisciplinary research team includes expertise in crash investigation, crash reconstruction, computer graphics, biomechanics of injuries, crash data analysis, trauma care, and all of the medical specialties associated with the Ryder Trauma Center at Jackson Memorial Hospital. More than 350 injured occupants and their crashes have been studied in depth. The purpose of this paper is to report on an observed pattern of liver lacerations suffered by drivers wearing shoulder belts, without the lap belt fastened and to assess the ability of existing crash test dummies to measure the potential for these injuries. During the initial years of the study, 48 cases of drivers protected by shoulder belts but without the lap belt fastened met the criteria for the study. Fifty percent of these drivers suffered liver lacerations. Further study showed that 22 of the crashes involved damage to the right front of the vehicle. Among the drivers in vehicles with right front damage, 92% sustained injuries to the liver. This observation indicated that 2-point belts were most likely to produce liver injuries in low severity frontal collisions when the crash direction is 1 to 2 o'clock. An analysis of the National Accident Sampling System for the years 1988-95 indicated that liver injuries constitute about 0.5% of the injuries suffered by drivers who are in tow-away crashes. NASS data showed that the risk of chest injury is more likely among drivers with automatic shoulder belts than drivers with 3-point manual belts. The crash test dummies showed no difference in chest injury measures. Finite element computer modeling demonstrated that the high deflection of the right lower rib on the Hybrid III dummy predicts the liver injuries in the 1 o'clock crashes. These higher deflections were less apparent at the location of the center chest deflection measurement device on the Hybrid III.

Light vehicle occupant ejections--a comprehensive investigation.

Occupant ejections, about 1.5% of all crash-involved occupant events, are relatively infrequent but very harmful events in highway crashes of light vehicles, including cars, pickup trucks, vans, and multipurpose vehicles (utility vehicles, jeeps, etc.). The disparity between frequency of harm to ejectees and ejection frequency is at least one order of magnitude. Partial ejections, although less frequent, have an incidence that is comparable to that of complete ejections, except for restrained occupants, where complete ejections are very infrequent. Notwithstanding the high effectiveness of safety belts in preventing ejections, and the multifold growth of safety belt use in the last 10 years, there is no detectable reduction in the ejection rate in the same period. Ejections per se and not other pre-ejection occupant impacts are responsible for the bulk of the harm to ejectees. Furthermore, ejected occupants sustain harm much larger than that which would have occurred, had these occupants not been ejected. "Closed glazing" is the leading ejection path. "Doors" and "windshield" are distant seconds. All glazing except the windshield fail overwhelmingly by disintegration. Latch failure is the primary mode of failure in opening doors. Hinges and other modes of failure are relatively minor concerns. The sources of data in this investigation are: the National Accident Sampling System for the years 1988 to 1991, and the Fatal Accident Reporting System for 1982 to 1992.

Occult abdominal injuries to airbag-protected crash victims: a challenge to trauma systems.

A multidisciplinary, automobile crash investigation team at the University of Miami School of Medicine, William Lehman Injury Research Center of Jackson Memorial Hospital/Ryder Trauma Center in Miami, Florida, is conducting a detailed medical and engineering study. The focus is restrained (seatbelts, airbag, or both) occupants involved in frontal crashes who have been severely injured. More than 60 crashes have been included in the study to date. Analysis of the initial data supports the general conclusion that restraint systems are working to reduce many of the head and chest injuries suffered by unrestrained occupants. However, abdominal injuries among airbag-protected occupants still occur. Some are found among occupants who appeared uninjured at the scene. Case examples are provided to illustrate abdominal injuries associated with airbag-protected crashes. The challenges of recognizing injuries to airbag-protected occupants are discussed. To assist in recognizing the extent of injuries to occupants protected by airbags, it is suggested that evidence from the crash scene be used in the triage decision. For the abdominal injury cases observed in this study, deformation of the steering system was the vehicle characteristic most frequently observed. The presence of steering wheel deformation is an indicator of increased likelihood of internal injury. This may justify transporting the victim to a trauma center for a closer examination for abdominal injuries.

Impact-induced car fires--a comprehensive investigation.

Impact-induced car fires still attract much attention, in spite of a reduction in the rate of their occurrence in recent years. This investigation addresses several issues concerning car fire rates as a function of model year and calendar year, and the sensitivity of these rates to car impact type, impact severity, and car size. Car fuel leak occurrence rates are examined in parallel. The resolution of these issues is based on a comprehensive examination of the voluminous car accident records complied for research purposes by the National Highway Traffic Safety Administration in the past ten years. The findings show a fire rate reduction, as model years progress from the early 1970s to the mid-1980s. A significant part of this reduction takes place across model year 1976, consistent with expectations based on Federal Motor Vehicle Safety Standard No. 301 (FMVSS 301), concerning car fuel system integrity, that became essentially effective in model year 1976. However, substantial reductions of fire rates and fuel leak occurrence rates are evident as model years progress well beyond 1976. Fire and fuel-leak rates are very sensitive to impact type and impact severity; however, rate reductions are evident irrespective of impact type and impact severity. Contrary to a widely entertained notion, fire and fuel-leak rates are found to be rather insensitive to car size.

The formation of uniform beams from long and thin radiators.

The coupling of long and thin radiators with nonaxisymmetric reflectors is considered for the production of generally rectangular beams with very good uniformity and attractive collection efficiencies. Reflector profiles are derived analytically, and cases of practical interest are discussed. Numerical results show that medium size beams (0.2-1 sr) may be obtained with collection efficiencies of 40% to 70%. Such beams are perfectly uniform over one angle while over the other they have nonuniformities generally lower than +/-10%. Limitations of the reflector dimensions and the effects of the radiator thickness are evaluated both analytically and by experimental observation.