The Macroeconomic Effects of Government Asset Purchases: Evidence from Postwar U.S. Housing Credit Policy

We document the portfolio activity of federal housing agencies and provide evidence on its impact on mortgage markets and the economy. Through a narrative analysis, we identify historical policy changes leading to expansions or contractions in agency mortgage holdings. Based on those regulatory events that we classify as unrelated to short-run cyclical or credit market shocks, we find that an increase in mortgage purchases by the agencies boosts mortgage lending, in particular refinancing, and lowers mortgage rates. Agency purchases also influence prices in other asset markets, stimulate residential investment, and expand homeownership. We compare these effects to those of conventional monetary policy shocks, and we provide evidence on the interactions between housing credit and monetary policies

The Dynamic Effects of Personal and Corporate Income Tax Changes in the United States: Reply

In this reply to a comment by Jentsch and Lunsford, we show that the evidence for economic and statistically significant macroeconomic effects of tax changes in Mertens and Ravn (2013) remains present for a range of asymptotically valid inference methods

The Dynamic Effects of Personal and Corporate Income Tax Changes in the United States

This paper estimates the dynamic effects of changes in taxes in the United States. We distinguish between changes in personal and corporate income taxes and develop a new narrative account of federal tax liability changes in these two tax components. We develop an estimator which uses narratively identified tax changes as proxies for structural tax shocks and apply it to quarterly post-WWII data. We find that short run output effects of tax shocks are large and that it is important to distinguish between different types of taxes when considering their impact on the labor market and on expenditure components

Plant Biomarker Pattern, Apples grown with various availability of organic nitrogen and with or witout the use of pesticides

In the recent years there has been an increasing focus on the quality and health value of organic plant products compared with conventional products. The use of pesticides and concentrated fertilisers in conventional agriculture implies a risk of effects on plant composition, which may affect health of the consumer (Brandt & Mølgaard, 2001). To determine if organically grown plant food could provide more or less benefits to health than conventional food, a first step is to investigate the differences in the composition and relative concentration of natural compounds in the plant products. In this project apples were grown with two levels of nitrogen availability and with or without the use of pesticides. The apples were screened for changes in the phytochemical composition and concentration. The work is affiliated to the project "Organic food and health" supported by the Danish Research Centre for Organic Farming (DARCOF). Biomarkers and biomarker patterns were presented in plants cultivated with low and high N and with pesticides. One biomarker was related to: • the type of N with and without pesticides • pesticides at high N and type of N without pesticides • pesticides at low and high N One biomarker pattern was related to: • the type of N • the type of N without pesticides • pesticides at low N and type of N without pesticides • pesticides at high N and type of N with pesticide

JUMPING STRATEGIES IN A VOLLEYBALL AND A BALLET SPECIFIC JUMP

INTRODUCTION The performance of a maximal vertical jump fram a static preparatory position (SQJ) or starting with a counter movement (CMJ) implies transformation of rotation about the hip, knee and ankle joints to a maximal translatory movement. Different strategies have been proposed for this transformation. Previously both sequential and simullaneous strategies have been proposed as optimal for maximal vertical jumping (1 & 2). The purpose of this study was to analyze ]umping strategies in a sport and dance specific maximal vertical jump. The hypothesis was that the technical demands of the Jumps would preset the strategy. Six male subjects participated in the study three professional ballet dancers and three elite volleyball players. In the ballet specific jump (BSJ) the legs were outward rotated, one foot was placed in front of and close to the other foot and the upper body kept upright. Three elite volleyball players performed the jump used for the smash (VSJ) including a three step preliminary run up and a farcefull arm swing. Afterwards all six subjects performed SQJ and CMJ. The ]umps were recorded on high speed film (500Hz) combined with registrations trom an AMTI force platform and EMG recordings from the major lower extremity muscles Net joint moments and joint work ware calculated by inverse dynamics. The strategy of the jumps was determined on the basis of angular kinematics and the pattern of nel joint moments of the two dominant joints RESULTS For BSJ the jumping height (h) was 0.22O.28m.The war!< contribution from the knee and ankle joint were 50-70% and 47-63% of the total work respectively while the work at the hip joint showed a negative contribution of 13-17% caused by a net hip flexor moment. Because of the specific ballet position the hip extension took place in the frontal plane and mgluteus maximus could not contribute to the extension. The concentric activity in mrectus femoris could partly explain the hip flexor moment. The knee and ankle joint initiated the extension phase simultaneously and the net joint moments peaked also simultaneously Therefore, the strategy could be defined as simultaneous. For VSJ h was 0.310.45m. The work contribution fram the knee and hip joints were 22-60% and 35-62% of the total work respectively. The hip joint began the extension phase before the body center of mass had reached its lowest position (sn The knee extension began 40-100ms after s.j. The peaks of the net joint moments of the hip and knee showed a similar pattern. Accordingly, the strategy could be defined as sequentiaL The sequential joint extension could partly be explained by the forcefull armswing pressing down and giving negative momentum in the downward phase and by this delaying the knee extension. In SQJ and CMJ h was 0.22-0.36m and 0.33-0AOm. The work contribution from the knee was 64.5%(SE 5.9) and 76.0% (SE 9.2) and from the hip 18.8% (SE 5.8) and 133% (SE 8.7). One ballet dancer and one volleyball player performed SQJ and CMJ with a simultaneous strategy while the otller four subjects used a sequential strategy. CONCLUSION In a maximal vertical jump fram ballet and from volleyball the technical demands preset the jumping strategy. When the subjects were asked to perform SQJ and CMJ the choice of strategy seemed individual and not connected to the training background. REFERENCES (1) Hudson, J.L. (1986). Med Sci. Sports Exerc, 18,242-251 (2) Babbert, M.F. & van lngen Schenau, G.J. (1986). J Biomechanics, 21, 249•26

Reduction of myocardial infarction by postischemic administration of the calpain inhibitor A-705253 in comparison to the Na(+)/H(+) exchange inhibitor Cariporide (R) in isolated perfused rabbit hearts

The calpain inhibitor A-705253 and the Na(+)/H(+) exchange inhibitor Cariporide (R) were studied in isolated perfused rabbit hearts subjected to 60 min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid solely or in combination at the beginning of reperfusion. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were performed. Myocardial infarct size and area at risk (transiently not perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 72.7 +/- 4.0% of the area at risk in untreated controls, but was significantly smaller in the presence of the inhibitors. The largest effect was observed with 10(-6) M A-705253, which reduced the infarcted area to 49.2 +/- 4.1% of the area at risk, corresponding to a reduction of 33.6%. Cariporide (R) at 10(-6) M reduced the infarct size to the same extent. The combination of both inhibitors, however, did not further improve cardioprotection. No significant difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, heart rate, or in the release of lactate dehydrogenase and creatine kinase from heart muscle