Dynamics of externalities: a second-order perspective

First-order approximation methods are a standard technique for analyzing the local dynamics of dynamic stochastic general equilibrium (DSGE) models. Although linear methods yield quite accurate solutions for a broad class of DSGE models, some important economic issues (e.g., portfolio choice and welfare) cannot be adequately addressed by first-order methods. This paper provides yet another case when first-order methods may be inadequate for capturing the business cycle properties of a DSGE model. In particular, the authors show that increasing returns to scale (due to production externalities) may induce asymmetric business cycles and nonlinear income effects that are not fully captured by linear approximation methods. For example, hump-shaped output dynamics can emerge even when externalities are below the threshold level required for indeterminacy, and output expansion tends to be smoother and longer, whereas contraction tends to be deeper but shorter-lived, as observed in the U.S. economy.Econometric models ; Externalities (Economics)

Dynamics of externalities: a second-order perspective

We show that increasing returns to scale (due to production externalities) may induce a strong degree of asymmetric income effects and nonlinear dynamics that are not fully appreciated by linear approximation methods. For example, hump-shaped output dynamics can emerge even when externalities are significantly below the threshold level required for indeterminacy, and output expansion tends to be smoother and longer while contraction tends to be deeper but shorter-lived. Thus, mild degree of externalities without triggering indeterminacy can potentially explain the asymmetric property of the business cycle and the hump-shaped output dynamics found in the empirical literature. Our results also suggest exercising caution when using linear approximation methods to analyze the local dynamics of models with market frictions and non-convexities.Externalities (Economics)

EFFECTS OF BASE OF SUPPORT AND VISUAL FEEDBACK ON STANDING BALANCE IN SUBJECTS WITH ANKLE SPRAIN

INTRODUCTION: Ankle sprain is arguably one of the most common injures in sport and can lead to significant impairment characterized by functional instability of the ankle. Base of support and visual feedback are two of the most important factors influencing the standing balance. Therefore, the purpose of this study was to investigate the effects of base of support and visual feedback on standing balance in subjects with and without ankle sprain

Assessing County-Level Water Footprints of Different Cellulosic- Biofuel Feedstock Pathways

While agricultural residue is considered as a near-term feedstock option for cellulosic biofuels, its sustainability must be evaluated by taking water into account. This study aims to analyze the county-level water footprint for four biofuel pathways in the United States, including bioethanol generated from corn grain, stover, wheat straw, and biodiesel from soybean. The county-level blue water footprint of ethanol from corn grain, stover, and wheat straw shows extremely wide variances with a national average of 31, 132, and 139 L of water per liter biofuel (Lw/Lbf), and standard deviation of 133, 323, and 297 Lw/Lbf, respectively. Soybean biodiesel production results in a blue water footprint of 313 Lw/Lbf on the national average with standard deviation of 894 Lw/Lbf. All biofuels show a greater green water footprint than the blue one. This work elucidates how diverse spatial resolutions affect biofuel water footprints, which can provide detailed insights into biofuels’ implications on local water sustainability

The water footprint of biofuel produced from forest wood residue via a mixed alcohol gasification process

Forest residue has been proposed as a feasible candidate for cellulosic biofuels. However, the number of studies assessing its water use remains limited. This work aims to analyze the impacts of forest-based biofuel on water resources and quality by using a water footprint approach. A method established here is tailored to the production system, which includes softwood, hardwood, and short-rotation woody crops. The method is then applied to selected areas in the southeastern region of the United States to quantify the county-level water footprint of the biofuel produced via a mixed alcohol gasification process, under several logistic systems, and at various refinery scales. The results indicate that the blue water sourced from surface or groundwater is minimal, at 2.4 liters per liter of biofuel (l/l). The regional-average green water (rainfall) footprint falls between 400 and 443 l/l. The biofuel pathway appears to have a low nitrogen grey water footprint averaging 25 l/l at the regional level, indicating minimal impacts on water quality. Feedstock mix plays a key role in determining the magnitude and the spatial distribution of the water footprint in these regions. Compared with other potential feedstock, forest wood residue shows promise with its low blue and grey water footprint

BIOMECHANICAL EFFECT OF GROUP EXERCISE PROGRAM USING STABILITY BALL ON THE COUNTER MOVEMENT JUMP

The purpose of this study was to evaluate the training effect of three-month group exercise program using stability ball. Ten female subjects were recruited to join this group exercise class for three months. The biomechanical parameters of counter-movement jump were collected before and after class. The average of maximal jumping height and the take-off velocity have significantly increased after three months. The group exercise program accoring American College of Sport Medicine trainig guideline which was designed in this study was helpful to increase the jump height of counter movement jump and to improve the biomechanical parameters of the landing