284 research outputs found
Very Cold Gas and Dark Matter
We have recently proposed a new candidate for baryonic dark matter: very cold
molecular gas, in near-isothermal equilibrium with the cosmic background
radiation at 2.73 K. The cold gas, of quasi-primordial abundances, is condensed
in a fractal structure, resembling the hierarchical structure of the detected
interstellar medium.
We present some perspectives of detecting this very cold gas, either directly
or indirectly. The H molecule has an "ultrafine" structure, due to the
interaction between the rotation-induced magnetic moment and the nuclear spins.
But the lines fall in the km domain, and are very weak. The best opportunity
might be the UV absorption of H in front of quasars. The unexpected cold
dust component, revealed by the COBE/FIRAS submillimetric results, could also
be due to this very cold H gas, through collision-induced radiation, or
solid H grains or snowflakes. The -ray distribution, much more
radially extended than the supernovae at the origin of cosmic rays
acceleration, also points towards and extended gas distribution.Comment: 16 pages, Latex pages, crckapb macro, 3 postscript figures, uuencoded
compressed tar file. To be published in the proceeedings of the
"Dust-Morphology" conference, Johannesburg, 22-26 January, 1996, D. Block
(ed.), (Kluwer Dordrecht
Non-tariff and overall protection: evidence across countries and over time
This paper analyzes the evolution of the incidence and intensity of non-tariff measures (NTMs). It extends earlier work by measuring protection from NTMs over time from a newly available database and provides evidence on the evolution of NTMs. In particular, building on Kee, Nicita and Olarreaga (2009), this paper estimates the ad valorem equivalents (AVEs) of NTMs for 97 countries at the product level over the period 1997 to 2015. We show that the incidence and the intensity of NTMs were both increasing over this period, with NTMs becoming an even more dominant source of trade protection. We are also able to investigate the evolution of overall protection derived jointly fromtariffs and NTMs. The results show that the overall protection level, for most countries and products, has not decreased despite the fall in tariffs associated with multilateral, regional and bilateral trade agreements in recent decades. We also document an increase in overall trade protection during the recent 2008 financial crisis. Overall, this study sheds light on an under-researched aspect of trade liberalization: the proliferation and increase of NTMs
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Sizing Up the Impact of Embassies on Exports
The purpose of this study is to test for the effects of trade promotion via the foreign service. We develop a Melitz-based model where firms are heterogeneous with respect to productivity and must pay a beachhead cost to enter a foreign market, which can be reduced by government spending on trade promotion. The model predicts that unilateral trade promotion allows medium-sized firms to export. We test this prediction using Swedish firm-level data and information on the opening and closing of Swedish embassies abroad using Norwegian firms as control group. Our results lend support to the predictions of the model, with large and medium-sized firms responding most strongly to the opening of embassies
Infrastructure and Trade
This paper explores the role that quality of infrastructure has on a country's trade performance, estimating a gravity model that incorporates bilateral tariffs and a number of indicators for the quality of infrastructure. The paper looks at the impact of the quality of infrastructure (road, airport, port and telecommunication, and the time required for customs clearance) on total bilateral trade and on trade in the automotive, clothing and textile sectors. In order to obtain unbiased estimators, multilateral resistances for tariffs and remoteness are introduced in the gravity equation. Moreover, the robustness of the results is tested by estimating a fixed-effect model, where bilateral indexes of the quality of infrastructure are included. The results can be summarised in four main findings: (i) bilateral tariffs, generally neglected in gravity regression of bilateral flows, have a significant negative impact on trade; (ii) quality of infrastructure is an important determinant of trade performance; (iii) port efficiency appears to have the largest impact on trade among all indicators of infrastructure; (iv) timeliness and access to telecommunication are relatively more important for export competitiveness in the clothing and automotive sector respectively
Factor Supplies and Specialization in the World Economy
A core prediction of the Heckscher-Ohlin theory is that countries specialize in goods in which they have a comparative advantage, and that the source of comparative advantage is differences in relative factor supplies. To examine this theory, we use the most extensive data set available and document the pattern of industrial specialization and factor endowment differences in a broad sample of rich and developing countries over a lengthy period (1970-92). Next, we develop an empirical model of specialization based on factor endowments, allowing for unmeasurable technological differences, and estimate it using panel data techniques. In addition to estimating the effects of factor endowments, we consider the alternative hypothesis that the level of aggregate productivity by itself can explain specialization. Our results clearly show the importance of factor endowments on specialization: relative endowments do matter
Trade Policy, Income Risk, and Welfare
This paper studies empirically the relationship between trade policy and individual income risk faced by workers. The analysis proceeds in three steps. First, longitudinal data on workers are used to estimate time-varying individual income risk parameters in various manufacturing sectors. The estimated income risk parameters and data on trade barriers are then used to analyze the relationship between trade policy and income risk. Finally, a simple dynamic general equilibrium model with incomplete markets is used assess the corresponding welfare costs. In the implementation of this methodology using Mexican data, we find that trade policy changes have a significant short run effect on income risk. Further, while the tariff level has an insignificant mean effect, it nevertheless changes the degree to which macroeconomic shocks affect income risk
The Transaction Costs Perspective on Standards as a Source of Trade and Productivity Growth
This paper discusses the design, implementation and use of standards from the perspective of transaction costs economics. A proper design and implementation of standards may lead to a considerable reduction of transaction costs, which enhances trade and, consequently, economic welfare. A major example is the use of containers, which has drastically changed the worldwide transport infrastructure, and lowered the costs of transport of goods considerably. The example of containers also shows that network externalities play a major role in the use of standards, and that, on the other hand, worldwide standards with large sunk investment costs may lead to a lock-in. This may call for government intervention in the design and use of standards, and in the transition processes to new standards. The paper provides ample further examples of standards and on the role of the government, or clubs, with respect to these standards
Key Factors Associated With Pulmonary Sequelae in the Follow-Up of Critically Ill COVID-19 Patients
Introduction: Critical COVID-19 survivors have a high risk of respiratory sequelae. Therefore, we aimed to identify key factors associated with altered lung function and CT scan abnormalities at a follow-up visit in a cohort of critical COVID-19 survivors. Methods: Multicenter ambispective observational study in 52 Spanish intensive care units. Up to 1327 PCR-confirmed critical COVID-19 patients had sociodemographic, anthropometric, comorbidity and lifestyle characteristics collected at hospital admission; clinical and biological parameters throughout hospital stay; and, lung function and CT scan at a follow-up visit. Results: The median [p25–p75] time from discharge to follow-up was 3.57 [2.77–4.92] months. Median age was 60 [53–67] years, 27.8% women. The mean (SD) percentage of predicted diffusing lung capacity for carbon monoxide (DLCO) at follow-up was 72.02 (18.33)% predicted, with 66% of patients having DLCO < 80% and 24% having DLCO < 60%. CT scan showed persistent pulmonary infiltrates, fibrotic lesions, and emphysema in 33%, 25% and 6% of patients, respectively. Key variables associated with DLCO < 60% were chronic lung disease (CLD) (OR: 1.86 (1.18–2.92)), duration of invasive mechanical ventilation (IMV) (OR: 1.56 (1.37–1.77)), age (OR [per-1-SD] (95%CI): 1.39 (1.18–1.63)), urea (OR: 1.16 (0.97–1.39)) and estimated glomerular filtration rate at ICU admission (OR: 0.88 (0.73–1.06)). Bacterial pneumonia (1.62 (1.11–2.35)) and duration of ventilation (NIMV (1.23 (1.06–1.42), IMV (1.21 (1.01–1.45)) and prone positioning (1.17 (0.98–1.39)) were associated with fibrotic lesions. Conclusion: Age and CLD, reflecting patients’ baseline vulnerability, and markers of COVID-19 severity, such as duration of IMV and renal failure, were key factors associated with impaired DLCO and CT abnormalities
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