3,997 research outputs found

    Business Cycles in Emerging Economies: The Role of Interest Rates

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    We find that in a sample of emerging economies business cycles are more volatile than in developed ones, real interest rates are countercyclical and lead the cycle, consumption is more volatile than output and net exports are strongly countercyclical. We present a model of a small open economy, where the real interest rate is decomposed in an international rate and a country risk component. Country risk is affected by fundamental shocks but, through the presence of working capital, also amplifies the effects of those shocks. The model generates business cycles consistent with Argentine data. Eliminating country risk lowers Argentine output volatility by 27% while stabilizing international rates lowers it by less than 3%.

    The Dilemma of Choosing Talent: Michael Jordans are Hard to Find

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    This paper explores the dilemma of choosing talent using NBA data from 1987-2003. We find that there is much uncertainty in selecting talent. If superstars are found they are usually identified early, however, more false positive exist than correct decisions with high draft picks. Our results suggest that the dilemma of choosing talent is not so much a winner’s curse but more like a purchase of a lottery ticket. Most times you lose but if you are going to win you must buy one.

    Position and velocity space diffusion of test particles in stochastic electromagnetic fields

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    The two--dimensional diffusive dynamics of test particles in a random electromagnetic field is studied. The synthetic electromagnetic fluctuations are generated through randomly placed magnetised ``clouds'' oscillating with a frequency ω\omega. We investigate the mean square displacements of particles in both position and velocity spaces. As ω\omega increases the particles undergo standard (Brownian--like) motion, anomalous diffusion and ballistic motion in position space. Although in general the diffusion properties in velocity space are not trivially related to those in position space, we find that energization is present only when particles display anomalous diffusion in position space. The anomalous character of the diffusion is only in the non--standard values of the scaling exponents while the process is Gaussian.Comment: 10 pages, 4 figure

    Design and numerical evaluation of full-authority flight control systems for conventional and thruster-augmented helicopters employed in NOE operations

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    The development and methodology is presented for development of full-authority implicit model-following and explicit model-following optimal controllers for use on helicopters operating in the Nap-of-the Earth (NOE) environment. Pole placement, input-output frequency response, and step input response were used to evaluate handling qualities performance. The pilot was equipped with velocity-command inputs. A mathematical/computational trajectory optimization method was employed to evaluate the ability of each controller to fly NOE maneuvers. The method determines the optimal swashplate and thruster input histories from the helicopter's dynamics and the prescribed geometry and desired flying qualities of the maneuver. Three maneuvers were investigated for both the implicit and explicit controllers with and without auxiliary propulsion installed: pop-up/dash/descent, bob-up at 40 knots, and glideslope. The explicit controller proved to be superior to the implicit controller in performance and ease of design

    Business Cycles in Emerging Economies:The Role of Interest Rates

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    This paper documents the empirical relation between the interest rates that emerging economies face in international capital markets and their business cycles. The dataset used in the study includes quarterly data for Argentina during 1983-2000 and for Brazil, Mexico, Korea, and Philippines, during 1994-2000. In this sample, interest rates are very volatile, strongly countercyclical, and strongly positively correlated with net exports. Output is very volatile and consumption is more volatile than output. These regularities are common to all emerging economies in the sample, but are not observed in a developed economy such as Canada. The paper presents a dynamic general equilibrium model of a small open economy, in which (i) firms have to pay for a fraction of the input bill before production takes place, and in which (ii) the labor supply is independent of consumption. Using a version of the model calibrated to Argentina’s economy, we find that interest rate shocks alone can explain 50% of output fluctuations and can generate business cycle patterns consistent with the regularities described above and with the major booms and recessions in Argentina in the last two decades. We conclude that interest rates are an important factor for explaining business cycles in emerging economies and further research should be devoted to fully understand their determination

    Benefits and Risks of Weight-Loss Treatment for Older, Obese Women

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    Background: A key issue in the treatment of obesity in older adults is whether the health benefits of weight loss outweigh the potential risks with respect to musculoskeletal injury. Objective: To compare change in weight, improvements in metabolic risk factors, and reported musculoskeletal adverse events in middle-aged (50-59 years) and older (65-74 years), obese women. Materials and methods: Participants completed an initial 6-month lifestyle intervention for weight loss, comprised of weekly group sessions, followed by 12 months of extended care with biweekly contacts. Weight and fasting blood samples were assessed at baseline, month 6, and month 18; data regarding adverse events were collected throughout the duration of the study. Results: Both middle-aged (n = 162) and older (n = 56) women achieved significant weight reductions from baseline to month 6 (10.1 +/- 0.68 kg and 9.3 +/- 0.76 kg, respectively) and maintained a large proportion of their losses at month 18 (7.6 +/- 0.87 kg and 7.6 +/- 1.3 kg, respectively); there were no significant differences between the two groups with respect to weight change. Older women further experienced significant reductions in systolic blood pressure, HbA(1c), and C-reactive protein from baseline to month 6 and maintained these improvements at month 18. Despite potential safety concerns, we found that older women were no more likely to experience musculoskeletal adverse events during the intervention as compared with their middle-aged counterparts. Conclusion: These results suggest that older, obese women can experience significant health benefits from lifestyle treatment for obesity, including weight loss and improvements in disease risk factors. Further investigation of the impact of weight loss on additional health-related parameters and risks (eg, body composition, muscular strength, physical functioning, and injuries) in older adults is needed.National Heart, Lung and Blood Institute R18HL73326University of FloridaDivision of Statistics and Scientific Computatio
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