3,667 research outputs found
Designing a Market for Tradable Emissions Permits
The economics literature shows that tradable emissions permits have important theoretical advantages over source-specific technical standards as a means for controlling pollution. But efficient, competitive markets in emissions may also be difficult to implement: transactions may be few with high negotiation costs; the market may be highly concentrated. Simple workable versions of the market concept may fail to take account of important complexities in the relationship between the pattern of emissions and the geographical distribution of pollution. This paper examines the feasibility of tradable permits, given these potential problems. Although the empirical part of the paper deals with a specific case—particulate sulfates in the Los Angeles airshed—the methods developed for investigating these issues have general applicability. Moreover, the particular market design that is proposed—an auction process that involves no net revenue collection by the state—has attractive features as a general model
Tradable Air Pollution Permits in the Overall Regulatory System: Problems of Regulatory Interactions
Because many environmental problems are associated with the production and use of energy, it is not surprising that the effects of policies in the two areas are often interdependent. This paper explores the interactions between the feasibility of an efficient market for emissions permits for sulfur oxides and the current state of air pollution, public utility and natural gas regulation. It shows how some of the opposition to tradable emissions permits can be traced to proposals to implement the reforms that redistribute wealth and the burden of regulatory uncertainty in ways that have greater economic impact than the potential efficiency gains of a market approach. It also examines how a tradable permits market and other regulatory reforms can be designed so as to avoid most of these problems
Barriers to Implementing Tradable Air Pollution Permits: Problems of Regulatory Interactions
Since 1977, the Environmental Protection Agency (EPA) has been developing and implementing an increasingly comprehensive system of controlled trading options for air pollution control. These programs introduce a limited market for the allocation of emissions among sources of air pollution. Starting with existing source-specific standards as a baseline, policies such as bubbles, emissions banks, netting and offsets allow firms to negotiate - within limits - trades of emissions permits in a manner that satisfies air quality standards at lower total costs. These trades, once agreed upon by the parties, in most cases must then be proposed to regulators as amendments to the existing set of source-specific standards
Fluid distribution kinetics during cardiopulmonary bypass
OBJECTIVE: The purpose of this study was to examine the isovolumetric distribution kinetics of crystalloid fluid during cardiopulmonary bypass. METHODS: Ten patients undergoing coronary artery bypass grafting participated in this prospective observational study. The blood hemoglobin and the serum albumin and sodium concentrations were measured repeatedly during the distribution of priming solution (Ringer's acetate 1470 ml and mannitol 15% 200 ml) and initial cardioplegia. The rate of crystalloid fluid distribution was calculated based on 3-min Hb changes. The preoperative blood volume was extrapolated from the marked hemodilution occurring during the onset of cardiopulmonary bypass. Clinicaltrials.gov: NCT01115166. RESULTS: The distribution half-time of Ringer's acetate averaged 8 minutes, corresponding to a transcapillary escape rate of 0.38 ml/kg/min. The intravascular albumin mass increased by 5.4% according to mass balance calculations. The preoperative blood volume, as extrapolated from the drop in hemoglobin concentration by 32% (mean) at the beginning of cardiopulmonary bypass, was 0.6-1.2 L less than that estimated by anthropometric methods (
Can perioperative hemodilution be monitored with non-invasive measurement of blood hemoglobin?
BACKGROUND
Trends in non-invasive measurements of blood hemoglobin (Hb) may be useful for identifying the need for transfusion in the perioperative period.
METHODS
Crystalloid fluid (5-20 mL/kg) was administered intravenously or by mouth to 30 volunteers and 33 surgical patients in five non-randomized clinical studies where Hb was measured on 915 occasions by non-invasive (Radical-7™) and invasive methodology. The hemodilution curves were compared by volume kinetic analysis and linear regression, with the slope and scattering of the data as key outcome measures.
RESULTS
The slope was 1.0, indicating unity between the two modes of measuring Hb when crystalloid fluid was infused in volunteers; however, only 40-45% of the variability in the non-invasive Hb could be explained by the invasive Hb. Patients undergoing major surgery, who showed the most pronounced hemodilution (median 24 g/L); non-invasive Hb explained 72% of the variability but indicated only half the magnitude of the invasive Hb changes (slope 0.48, P < 0.001 versus the volunteers). Simulations based on volume kinetic parameters from the volunteers showed 25% less plasma volume expansion after infusion when based on non-invasive as compared to invasive Hb, while no difference was found during infusion.
CONCLUSIONS
In volunteers the non-invasive Hb had good accuracy (low bias) but poor precision. In surgical patients the non-invasive Hb had good precision but systematically underestimated the hemodilution. Despite severe limitations, the non-invasive technology can be used to follow Hb trends during surgery if supported by occasional invasive measurements to assure acceptable quality of the hemodilution curve.
TRIAL REGISTRATIONS
ControlledTrials.gov NCT01195025, NCT01062776, NCT01458678, NCT03848507, and NCT01360333 on September 3, 2010, February 4, 2010, October 25, 2011, February 20, 2019, and May 25, 2011, respectively
Implementing tradable permits for sulfur oxides emissions : a case study in the South Coast Air Basin
Tradable emissions permits have important theoretical advantages over source-specific technical standards as a means for controlling pollution. Nonetheless, difficulties can arise in trying to implement an efficient, competitive market in emissions permits. Simple workable versions of the market concept may fail to achieve the competitive equilibrium, or to take account of important complexities in the relationship between the pattern of emissions and the geographical distribution of pollution. Existing regulatory law may severely limit the range of market opportunities that states can adopt.
This report examines the feasibility of tradable permits for controlling particulate sulfates in the Los Angeles airshed. Although the empirical part of the paper deals with a specific case, the methods developed have general applicability. Moreover, the particular market design that is proposed -- an auction process that involves no net revenue collection by the state -- has attractive features as a general model
Tradable Air Pollution Permits in the Overall Regulatory System: Problems of Regulatory Interactions
Because many environmental problems are associated with the production and use of energy, it is not surprising that the effects of policies in the two areas are often interdependent. This paper explores the interactions between the feasibility of an efficient market for emissions permits for sulfur oxides and the current state of air pollution, public utility and natural gas regulation. It shows how some of the opposition to tradable emissions permits can be traced to proposals to implement the reforms that redistribute wealth and the burden of regulatory uncertainty in ways that have greater economic impact than the potential efficiency gains of a market approach. It also examines how a tradable permits market and other regulatory reforms can be designed so as to avoid most of these problems
Minimal shedding of the glycocalyx layer during abdominal hysterectomy
Funding Information: This project was funded by the Stockholm City Council, the Kleberg Foundation and Riga Stradins University. Publisher Copyright: © 2017 The Author(s).Background: Surgery with and without hypervolaemia may cause shedding (breakdown) of the endothelial glycocalyx layer, but the severity of this problem is unclear. Methods: In this preliminary report of a larger clinical trial, the plasma and urine concentrations of three biomarkers of glycocalyx shedding (syndecan-1, hyaluronic acid and heparan sulfate) were measured in seven patients before, during, and after open hysterectomy. The fluid therapy consisted of 25ml/kg (approximately 2l) of Ringer's lactate, which was infused over 30min when the surgery started. The resulting plasma volume expansion at the end of the infusion was estimated from the haemodilution. Results: The mean plasma concentration of syndecan-1 was 21.7ng/ml before surgery and averaged 19.7ng/ml during and after the surgery. The plasma concentration of hyaluronic acid decreased from 38.0 to 27.7ng/ml (P<0.05), while heparan sulfate increased from 3.4 to 5.5μg/ml (P<0.05). The urine concentrations of syndecan-1 decreased significantly, while they increased for hyaluronic acid and heparan sulfate. Despite the vigorous fluid load, the urine flow did not exceed 1ml/min. Conclusions: No clear evidence was found for shedding of the endothelial glycocalyx layer when 2l of Ringer's lactate was infused over 30min during abdominal hysterectomy. Urine analyses yielded patterns of changes that differed from those in plasma. Trial registration:ISRCTN81005631. Registered May 17, 2016.publishersversionPeer reviewe
Concentrated urine, low urine flow, and postoperative elevation of plasma creatinine: A retrospective analysis of pooled data.
Elevations of plasma creatinine are common after major surgery, but their pathophysiology is poorly understood. To identify possible contributing mechanisms, we pooled data from eight prospective studies performed in four different countries to study circumstances during which elevation of plasma creatinine occurs. We included 642 patients undergoing mixed major surgeries, mostly open gastrointestinal. Plasma and urinary creatinine and a composite index for renal fluid conservation (Fluid Retention Index, FRI) were measured just before surgery and on the first postoperative morning. Urine flow was measured during the surgery. The results show that patients with a postoperative increase in plasma creatinine by >25% had a high urinary creatinine concentration (11.0±5.9 vs. 8.3±5.6 mmol/L; P 25% also showed higher creatinine and a higher FRI value on the first postoperative morning (P 50% of baseline were associated with slightly lower mean arterial pressure (73 ± 10 vs. 80 ± 12 mmHg; P< 0.005). We conclude that elevation of plasma creatinine in the perioperative period was associated with low urine flow and greater blood loss during surgery and with concentrated urine both before and after the surgery. Renal water conservation-related mechanisms seem to contribute to the development of increased plasma creatinine after surgery
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