274 research outputs found
Equatorial ozone characteristics as measured at Natal (5.9 deg S, 35.2 deg W)
Ozone density profiles obtained through electrochemical concentration cell (ECC) sonde measurements at Natal were analyzed. Time variations, as expected, are small. Outstanding features of the data are tropospheric densities substantially higher than those measured at other stations, and also a total ozone content that is higher than the averages given by satellite measurements
Air/Sea Transfer of Highly Soluble Gases Over Coastal Waters
The deposition of soluble trace gases to the sea surface is not well studied due to a lack of flux measurements over the ocean. Here we report simultaneous air/sea eddy covariance flux measurements of water vapor, sulfur dioxide (SO2), and momentum from a coastal North Atlantic pier. Gas transfer velocities were on average about 20% lower for SO2 than for H2O. This difference is attributed to the difference in molecular diffusivity between the two molecules (DSO2/DH2O = 0.5), in reasonable agreement with bulk parameterizations in air/sea gas models. This study demonstrates that it is possible to observe the effect of molecular diffusivity on air-side resistance to gas transfer. The slope of observed relationship between gas transfer velocity and friction velocity is slightly smaller than predicted by gas transfer models, possibly due to wind/wave interactions that are unaccounted for in current models
The Chilean Pension System at 25 Years: The Evolution of a Revolution
The 1981 reform of the Chilean pension system was revolutionary at its time. It was the first instance of a mature public Pay-As-You-Go social security system being converted into a mandatory defined contribution system managed by the private sector. This paper contends that a unique confluence of events were responsible for this change. The rise of a dictatorship in Chile, a struggling public retirement system, and a cadre of Chicago oriented economists determined to make Chile a model free market neoliberal economy. This was later followed by the Washington Consensus and the promotion of Chilean reform by the World Bank. This paper analyzes the Chilean reform and its subsequent development; evaluating it on both efficiency and equity grounds. While the evidence for efficiency gains is mixed there is little doubt that equity has suffered under the new system. Nevertheless, it continues to evolve and equity concerns are increasingly being addressed
The Chilean Pension System at 25 Years: The Evolution of a Revolution
The 1981 reform of the Chilean pension system was revolutionary at its time. It was the first instance of a mature public Pay-As-You-Go social security system being converted into a mandatory defined contribution system managed by the private sector. This paper contends that a unique confluence of events were responsible for this change. The rise of a dictatorship in Chile, a struggling public retirement system, and a cadre of Chicago oriented economists determined to make Chile a model free market neoliberal economy. This was later followed by the Washington Consensus and the promotion of Chilean reform by the World Bank. This paper analyzes the Chilean reform and its subsequent development; evaluating it on both efficiency and equity grounds. While the evidence for efficiency gains is mixed there is little doubt that equity has suffered under the new system. Nevertheless, it continues to evolve and equity concerns are increasingly being addressed
Personal and Societal Health Quality Lost to Tuberculosis
Background: In developed countries, tuberculosis is considered a disease with little loss of Quality-Adjusted Life Years (QALYs). Tuberculosis treatment is predominantly ambulatory and death from tuberculosis is rare. Research has shown that there are chronic pulmonary sequelae in a majority of patients who have completed treatment for pulmonary tuberculosis (PTB). This and other health effects of tuberculosis have not been considered in QALY calculations. Consequently both the burden of tuberculosis on the individual and the value of tuberculosis prevention to society are underestimated. We estimated QALYs lost to pulmonary TB patients from all known sources, and estimated health loss to prevalent TB disease.
Methodology/Principal Findings: We calculated values for health during illness and treatment, pulmonary impairment after tuberculosis (PIAT), death rates, years-of-life-lost to death, and normal population health. We then compared the lifetime expected QALYs for a cohort of tuberculosis patients with that expected for comparison populations with latent tuberculosis infection and without tuberculosis infection. Persons with culture-confirmed tuberculosis accrued fewer lifetime QALYs than those without tuberculosis. Acute tuberculosis morbidity cost 0.046 QALYs (4% of total) per individual. Chronic morbidity accounted for an average of 0.96 QALYs (78% of total). Mortality accounted for 0.22 QALYs lost (18% of total). The net benefit to society of averting one case of PTB was about 1.4 QALYs.
Conclusions/Significance: Tuberculosis, a preventable disease, results in QALYs lost owing to illness, impairment, and death. The majority of QALYs lost from tuberculosis resulted from impairment after microbiologic cure. Successful TB prevention efforts yield more health quality than previously thought and should be given high priority by health policy makers. (Refer to Abstracto S1 for Spanish language abstract
Coil optimization for electromagnetic levitation using a genetic like algorithm
he technique of electromagnetic levitation (EML) provides a means for thermally processing an electrically conductive specimen in a containerless manner. For the investigation of metallicliquids and related melting or freezing transformations, the elimination of substrate-induced nucleation affords access to much higher undercooling than otherwise attainable. With heating and levitation both arising from the currents induced by the coil, the performance of any EML system depends on controlling the balance between lifting forces and heating effects, as influenced by the levitation coil geometry. In this work, a genetic algorithm is developed and utilized to optimize the design of electromagnetic levitation coils. The optimization is targeted specifically to reduce the steady-state temperature of the stably levitated metallic specimen. Reductions in temperature of nominally 70 K relative to that obtained with the initial design are achieved through coil optimization, and the results are compared with experiments foraluminum. Additionally, the optimization method is shown to be robust, generating a small range of converged results from a variety of initial starting conditions. While our optimizationcriterion was set to achieve the lowest possible sample temperature, the method is general and can be used to optimize for other criteria as well
Will the Recovery Continue? Four Fragile Markets, Four Years Later
In this brief, Research Scholar Greg Hannsgen and President Dimitri B. Papadimitriou focus on the risks and possibilities ahead for the US economy. Using a Keynesian approach and drawing from the commentary of other observers, they analyze publicly available data in order to assess the strength and durability of the expansion that probably began in 2009. They focus on four broad groups of markets that have shown signs of stress for the last several years: financial markets, markets for household goods and services, commodity markets, and labor markets. This kind of analysis does not yield numerical forecasts but it can provide important clues about the short-term outlook for the country's economic well-being, and cast light on some longer-run threats. In particular, dangers and stresses in the financial and banking systems are presently very serious, and labor market data show every sign of a widespread and severe weakness in aggregate demand. Unless there is new resolve for effective government action on the jobs front, drastic cuts in much-needed federal, state, and local programs will become the order of the day in the United States, as in much of Europe
Does Excessive Sovereign Debt Really Hurt Growth? A Critique of 'This Time is Different', by Reinhart and Rogoff
The worst global downturn since the Great Depression has caused ballooning budget deficits in most nations, as tax revenues collapse and governments bail out financial institutions and attempt countercyclical fiscal policy. With notable exceptions, most economists accept the desirability of expansion of deficits over the short term but fear possible long-term effects. There are a number of theoretical arguments that lead to the conclusion that higher government debt ratios might depress growth. There are other arguments related to more immediate effects of debt on inflation and national solvency. Research conducted by Carmen Reinhart and Kenneth Rogoff is frequently cited to demonstrate the negative impacts of public debt on economic growth and financial stability. In this paper we critically examine their work. We distinguish between a nation that operates with its own floating exchange rate and nonconvertible (sovereign) currency, and a nation that does not. We argue that Reinhart and Rogoff's results are not relevant to the case of the United States
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