Entire US Research Articles

Carbapenem-resistant Enterobacteriaceae and the correlation between carbapenem and fluoroquinolone usage and resistance in the US military health system

Whether carbapenem or fluoroquinolone usage is correlated with carbapenem-resistant Enterobacteriaceae (CRE) has not been investigated at the level of an entire US nationwide managed health care system. We analyzed 75 million person-years of surveillance and 1,969,315 cultures from all 266 hospitals in the geographically dispersed US military health system. Incidences of CRE remained under 1 case per 100,000 person-years. Incidences of CRE increased relative to 2005 baseline levels in 3 of 7 subsequent years, then decreased in 2012 (P<0.05). Incident proportions of carbapenem resistance (CR) differed significantly among years, geographical regions, and bacterial species. Although use and resistance strongly correlated (R>0.80) for several “drug-bug” combinations, none were significant at the national or facility level. One exception was that inpatient consumption of fluoroquinolones was significantly correlated (P=0.0007) with CR in Escherichia coli when data from the major referral centers of the Southern and Northern regions were combined.

Hospitalization Cost per Case of Neonatal Herpes Simplex Virus Infection From Claims Data

The purpose of this study was to estimate the average excess inpatient cost of neonatal herpes simplex virus (NHSV) infection from 2005 to 2009 insurance claims data. The estimated adjusted average excess inpatient cost for neonate admissions with HSV diagnosis and >7 days of hospitalization was $40,044 [95% confidence interval (CI), $33,529-$47,775]. When disaggregated by the days of admission, cost estimates were: 8-13 days, $23,918 [CI, $19,490-$29,282]; 14-21 days, $44,358 [CI, $34,654-$56,673]; >21 days, $68,916 [CI, $49,905-$94,967]). Although these estimates are not representative of the entire US, they can inform future economic evaluation studies on NHSV interventions.

Minimal benefit of earlier-than-recommended repeat colonoscopy among US Medicare enrollees following a negative colonoscopy.

A large proportion of US Medicare beneficiaries undergo earlier-than-recommended follow-up colonoscopies after negative screening colonoscopy. Such practice entails substantial cost and added risk. To compare the risk of colorectal cancer (CRC) associated with varying follow-up colonoscopy intervals following a negative colonoscopy, and to determine whether the potential benefit of a shorter colonoscopy follow-up interval would differ by gender. We conducted a weighted cohort study using the Surveillance, Epidemiology and End Results-Medicare linked database (1991-2006) among 932,370 Medicare enrollees who are representative of the entire US elderly population. We compared the cumulative incidence of CRC among patients who underwent follow-up colonoscopies at different intervals following a negative colonoscopy. The primary outcome was incident CRC. The eligible study cohort (n = 480,864) included 106,924 patients who underwent ≥1 colonoscopy. Men were more likely to require polypectomy during their initial colonoscopy than women. Compared to the recommended 9-10 year follow-up colonoscopy interval, an interval of 5-6 years was associated with the largest CRC cumulative risk reduction [i.e. 0.17% (95% CI: 0.009-0.32%)]. The magnitude of risk reduction associated with shorter colonoscopy follow-up intervals was not significantly different between men and women. Among elderly individuals who undergo a negative colonoscopy, the magnitude of reduction in the cumulative CRC risk afforded by earlier-than-recommended follow-up colonoscopy is quite small, and probably cannot justify the risk and cost of increased colonoscopy frequency. In addition, there are insufficient differences between men and women to warrant gender-specific recommendations.

Effect of insurance expansion on utilization of inpatient surgery.

Enhanced access to preventive and primary care services is a primary focus of the Affordable Care Act, but the potential effect of this law on surgical care is not well defined. To estimate the differential effect of insurance expansion on utilization of discretionary vs nondiscretionary inpatient surgery with Massachusetts health care reform as a natural experimental condition. We used the state inpatient databases from Massachusetts and 2 control states (New Jersey and New York) to identify nonelderly adult patients (aged 19-64 years) who underwent discretionary vs nondiscretionary surgical procedures from January 1, 2003, through December 31, 2010. We defined discretionary surgery as elective, preference-sensitive procedures (eg, joint replacement and back surgery) and nondiscretionary surgery as imperative and potentially life-saving procedures (eg, cancer surgery and hip fracture repair). All surgical procedures in the study and control populations. Using July 1, 2007, as the transition point between the prereform and postreform periods, we performed a difference-in-differences analysis to estimate the effect of insurance expansion on rates of discretionary and nondiscretionary surgical procedures in the entire study population and for subgroups defined by race, income, and insurance status. We then extrapolated our results from Massachusetts to the entire US population. We identified a total of 836 311 surgical procedures during the study period. Insurance expansion was associated with a 9.3% increase in the use of discretionary surgery in Massachusetts (P = .02). Conversely, the rate of nondiscretionary surgery decreased by 4.5% (P = .009). We found similar effects for discretionary surgery in all subgroups, with the greatest increase observed for nonwhite participants (19.9% [P < .001]). Based on the findings in Massachusetts, we estimated that full implementation of national insurance expansion would yield an additional 465 934 discretionary surgical procedures by 2017. Insurance expansion in Massachusetts was associated with increased rates of discretionary surgery and a concurrent decrease in rates of nondiscretionary surgery. If similar changes are seen nationally under the Affordable Care Act, the value of insurance expansion for surgical care may depend on the relative balance between increased expenditures and potential health benefits of greater access to elective inpatient procedures.

The potential for double-loop learning to enable landscape conservation efforts.

As conservation increases its emphasis on implementing change at landscape-level scales, multi-agency, cross-boundary, and multi-stakeholder networks become more important. These elements complicate traditional notions of learning. To investigate this further, we examined structures of learning in the Landscape Conservation Cooperatives (LCCs), which include the entire US and its territories, as well as parts of Canada, Mexico, and Caribbean and Pacific island states. We used semi-structured interviews, transcribed and analyzed using NVivo, as well as a charrette-style workshop to understand the difference between the original stated goals of individual LCCs and the values and purposes expressed as the collaboration matured. We suggest double-loop learning as a theoretical framework appropriate to landscape-scale conservation, recognizing that concerns about accountability are among the valid points of view that must be considered in multi-stakeholder collaborations. Methods from the social sciences and public health sectors provide insights on how such learning might be actualized.

A regression approach for estimation of anthropogenic heat flux based on a bottom-up air pollutant emission database

A statistical regression method is presented for estimating hourly anthropogenic heat flux (AHF) using an anthropogenic pollutant emission inventory for use in mesoscale meteorological and air-quality modeling. Based on bottom-up AHF estimated from detailed energy consumption data and anthropogenic pollutant emissions of carbon monoxide (CO) and nitrogen oxides (NOx) in the US National Emission Inventory year 2005 (NEI-2005), a robust regression relation between the AHF and the pollutant emissions is obtained for Houston. This relation is a combination of two power functions (Y = aXb) relating CO and NOx emissions to AHF, giving a determinant coefficient (R2) of 0.72. The AHF for Houston derived from the regression relation has high temporal (R = 0.91) and spatial (R = 0.83) correlations with the bottom-up AHF. Hourly AHF for the whole US in summer is estimated by applying the regression relation to the NEI-2005 summer pollutant emissions with a high spatial resolution of 4-km. The summer daily mean AHF range 10–40 W m−2 on a 4 × 4 km2 grid scale with maximum heat fluxes of 50–140 W m−2 for major US cities. The AHFs derived from the regression relations between the bottom-up AHF and either CO or NOx emissions show a small difference of less than 5% (4.7 W m−2) in city-scale daily mean AHF, and similar R2 statistics, compared to results from their combination. Thus, emissions of either species can be used to estimate AHF in the US cities. An hourly AHF inventory at 4 × 4 km2 resolution over the entire US based on the combined regression is derived and made publicly available for use in mesoscale numerical modeling.

Identifying dominant controls on hydrologic parameter transfer from gauged to ungauged catchments – A comparative hydrology approach

Summary Daily streamflow information is critical for solving various hydrologic problems, though observations of continuous streamflow for model calibration are available at only a small fraction of the world’s rivers. One approach to estimate daily streamflow at an ungauged location is to transfer rainfall–runoff model parameters calibrated at a gauged (donor) catchment to an ungauged (receiver) catchment of interest. Central to this approach is the selection of a hydrologically similar donor. No single metric or set of metrics of hydrologic similarity have been demonstrated to consistently select a suitable donor catchment. We design an experiment to diagnose the dominant controls on successful hydrologic model parameter transfer. We calibrate a lumped rainfall–runoff model to 83 stream gauges across the United States. All locations are USGS reference gauges with minimal human influence. Parameter sets from the calibrated models are then transferred to each of the other catchments and the performance of the transferred parameters is assessed. This transfer experiment is carried out both at the scale of the entire US and then for six geographic regions. We use classification and regression tree (CART) analysis to determine the relationship between catchment similarity and performance of transferred parameters. Similarity is defined using physical/climatic catchment characteristics, as well as streamflow response characteristics (signatures such as baseflow index and runoff ratio). Across the entire US, successful parameter transfer is governed by similarity in elevation and climate, and high similarity in streamflow signatures. Controls vary for different geographic regions though. Geology followed by drainage, topography and climate constitute the dominant similarity metrics in forested eastern mountains and plateaus, whereas agricultural land use relates most strongly with successful parameter transfer in the humid plains.

Abstract 327: Six months follow-up of “My Unlimited Potential”, A 12-week Worksite, Multi-Component, Lifestyle Intervention for Improving Cardiometabolic Health in High Risk Persons

Background: With about 59% of the entire US population currently in the work force, the American Heart Association has emphasized worksite-based interventions to improve cardiovascular health among the working population. The primary aim of this study was to assess effectiveness of an ongoing multi-component, lifestyle improvement program (My Unlimited Potential [MyUP]) extending into 6 months, among employees of Baptist Health South Florida (BHSF), a large not-for-profit health care system. Methods: BHSF employees with 2 or more Cardiometabolic risk factors, such as total cholesterol ≥ 200 mg/dl, systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, hemoglobin A1C ≥ 6.5%, and body mass index (BMI) ≥ 30 were considered for the study. Behavioral interventions were focused on dietary and physical activity modifications. Results: Overall 202 (48±10 years, 78% females) employees who enrolled in the MyUP wellness program. The retention of subjects was high with 89% (n=181) at 12 weeks and 80% (n=162) at 6 months. The table and figure below demonstrate the baseline, 12 week and 6 months averages in anthropometric and laboratory profile in participants. Comparing follow-up from 3 months to that at 6 months, clinically meaningful improvement in endpoints were especially noted for BMI, BP, HDL targets, and reducing burden of systemic inflammation (figure). Conclusion: These findings suggest that an intensive behavioral modification intervention program, delivered to employees in a health care setting, results in both significant short and intermediate term benefit in weight reduction, improved blood pressure control and hbA1c, and concomitantly improves cardio-metabolic risk profile. Further follow-up is in progress to ascertain whether these benefits are sustainable over longer periods.

Abstract 252: Champion Phoenix Study Economic Results: Direct Hospitalization Costs of Patients Receiving Clopidogrel or Cangrelor During Percutaneous Coronary Intervention

Background: Current guidelines recommend use of antiplatelet agents (oral P2Y12 inhibitors and/or GPIIb/IIIa inhibitors) in combination with antithrombin agents (bivalirudin or heparins) for PCI. Cangrelor, a new, intravenous, rapid on/off-set P2Y12 inhibitor reduced ischemic events vs. clopidogrel in the CHAMPION PHOENIX Trial. An economic substudy, from the perspective of the US healthcare system, was designed utilizing a sample of the US trial patients to identify the direct medical costs during index hospitalization among cangrelor vs. clopidogrel patients and the subgroup receiving bivalirudin as antithombin therapy during PCI. Methods and Results: Hospital bills were collected from a proportion of US patients in the CHAMPION PHOENIX trial. All US hospitals (n=53) were invited and 22 participated. Hospital bills were matched to clinical data from the CHAMPION PHOENIX trial endpoints including death, myocardial infarction (MI), unplanned revascularization, stent thrombosis, intraprocedural thrombotic complications, and major bleeding. Events were adjudicated by a blinded, independent committee using predefined criteria. A total of 1117 hospital bills (27.3% of US mITT population) were collected and analyzed. Patient demographics and comorbidities were similar to the overall CHAMPION PHOENIX US mITT population. Hospital costs were determined by multiplying itemized hospital charges and the cost-center specific cost-to-charge ratio obtained from hospital's Medicare cost report. Median index hospitalization costs for patients receiving cangrelor vs. clopidogrel were compared. Statistical significance was assessed using a Wilcoxon Sum-Rank test at a significance level of P&lt;0.05. The median index hospitalization cost of patients receiving cangrelor (N=560) was $10308 vs. $10738 with clopidogrel (N=557) (P = NS), a numerical savings of $430. The median index hospitalization cost of patients receiving both cangrelor/bivalirudin (N=383) was $11139 vs. $11661 with clopidogrel/bivalirudin (N=389) (P = NS), a numerical savings of $522. There was no difference in the mean length-of-stay. MI (Δ$4675), stent thrombosis (Δ$7881), intraprocedural stent thrombosis (Δ$9342), and ACUITY major bleeding (Δ$6181) were associated with increased cost of hospitalization regardless of treatment (all p&lt;0.05). Conclusions: This preliminary analysis of hospital bills from a subset of the CHAMPION PHOENIX US mITT population reveals a numerical reduction in direct medical costs for cangrelor patients (with or without bivalirudin). As these data represent a proportion of the population in a trial of very low event rates, further analysis is necessary utilizing multiple imputation methodology, and regression modeling to provide more robust data to identify factors associated with increased index hospitalization costs among the entire CHAMPION PHOENIX US mITT population.

Tangent Portfolio Weights without Explicitly Specified Expected Returns

In this article, I propose an extension of the Treynor-Black model to a case where the investor is not fully invested in the stock market at the outset and there is no need to explicitly specify securities' expected returns. I derive explicit tangent portfolio weights based on a factor model of securities' expected returns. The computational burden of the model is linear in the number of securities in the portfolio and does not involve any matrix inversion. I present an empirical application using the market model of Sharpe, the three-factor model of Fama and French and the four-factor model of Carhart with up to 30 industry portfolios between 1963 and 2012 and up to 1000 US stocks starting in 1992 until 2012. The portfolios perform well out-of-sample relative to the entire US value-weighted stock market portfolio with dividends reinvested from the Center for Research in Security Prices. The proposed framework can be extended in a straightforward way to time-varying models with multiple state variables affecting securities' expected returns and factor loadings.

Rural-Urban Differences in Access to Specialist Providers of Colorectal Cancer Care in the United States: A Physician Workforce Issue.

Although early detection and treatment of colorectal cancer has been shown to improve outcomes, geographic proximity may influence access to these services. To examine the disparities that may exist in colorectal cancer screening and treatment by comparing the distribution of providers of these services in rural and urban counties in the United States. A retrospective population-based study using data obtained from the 2009 Area Resource File for the entire US population within each county. Counties in the United States were categorized as rural or urban using rural-urban continuum codes as our primary exposure. The proportion of gastroenterologists, general surgeons, and radiation oncologists per 100,000 people in each county was estimated as primary outcomes. Multivariate linear regression analysis adjusted for county-level socioeconomic variables, such as percentages of females, blacks, population without insurance, those with a high school diploma, and median household income, to estimate the relative density of each category of these providers between urban and rural counties. In total, 3220 counties were identified, comprising 1807 rural and 1413 urban counties. An unadjusted analysis showed an increased density of gastroenterologists, general surgeons, and radiation oncologists per 100,000 people in urban vs rural counties. A multivariable analysis revealed a significantly higher density of gastroenterologists (1.63; 95% CI, 1.40-1.85; P < .001), general surgeons (2.01; 95% CI, 1.28-2.73; P < .001), and radiation oncologists (0.68; 95% CI, 0.59-0.77; P < .001) per 100,000 people living in urban vs rural counties. A rural-urban disparity exists in the density of gastroenterologists, general surgeons, and radiation oncologists who traditionally provide colorectal cancer screening services and treatment. This might affect access to these services and may negatively influence outcomes for colorectal cancer in rural areas.

Tangent portfolio weights without explicitly specified expected returns

In this article, I propose an extension of the Treynor–Black model to a case where the investor is not fully invested in the stock market at the outset and there is no need to explicitly specify securities’ expected returns. I derive explicit tangent portfolio weights based on a factor model of securities’ expected returns. The computational burden of the model is linear in the number of securities in the portfolio and does not involve any matrix inversion. I present an empirical application using the market model of Sharpe, the three-factor model of Fama and French and the four-factor model of Carhart with up to 30 industry portfolios between 1963 and 2012 and up to 1000 US stocks starting in 1992 until 2012. The portfolios perform well out-of-sample relative to the entire US value-weighted stock market portfolio with dividends reinvested from the Center for Research in Security Prices. The proposed framework can be extended in a straightforward way to time-varying factor models with multiple state variables affecting securities’ expected returns and factor loadings.

An activity-based freight mode choice microsimulation model

This study embarked upon the development of a nationwide freight activity microsimulation as an acceptable analysis tool for policy assessments. Mode choice component of a large-scale behavioral microsimulation framework, named Freight Activity Microsimulation Estimator (FAME) was developed and validated in this study. The results of a nationwide establishment survey, discussed in earlier studies, are used to develop the mode choice model for the entire US. Despite many previous freight mode choice models, the proposed model works at the disaggregate level of firm-to-firm. A new concept for firm-types is implemented in FAME to keep the computational burden at a reasonable level and to diminish the need for highly disaggregated data. A total of 45 206 firm-types were synthesized in the US, among which more than 14·8 billion tonnes of domestic shipments were simulated. Total tonnage, value, and tonne-mile of commodities for each mode were obtained as the final output, which showed a satisfactory match with public freight data in the US.

Abstract P124: My Unlimited Potential: Achieving Weight, Fitness And Cardio-metabolic Health Objectives Using A 12-week, Multicomponent, Behavioral Intervention

Background: With about 59% of the entire US population currently in the work force, American Heart Association has emphasized worksite-based interventions to improve cardiovascular health among the working population. The primary aim of this study was to assess the short-term (12 weeks) efficacy of an ongoing multi-component, behavioral intervention improvement program (My Unlimited Potential (myUP), among employees of Baptist Health South Florida (BHSF), a large not-for-profit health care system. Methods: BHSF employees with two or more Cardio-metabolic risk factors, such as total cholesterol ≥ 200 mg/dl, systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, hemoglobin A1C ≥ 6.5%, and body mass index (BMI) ≥ 30 were considered for the study. Behavioral interventions were focused on diet and physical activity modifications. Results: Overall 202 (48±10 years, 78% females) employees enrolled in myUP wellness program. The retention of subjects was high with 89% (n=181) of subjects following up at 12 weeks. The figure below demonstrates the baseline, follow-up and estimated mean change in anthropometric, exercise capacity on treadmill test and CM participants. BMI reduction &gt;5% was noted in 38% of the participants. Significantly higher, clinically meaningful, endpoints, especially in attaining blood pressure goals and exercise capacity (&gt;10 METS), during the short-term follow-up in this behavioral intervention program (figure), were achieved. Conclusion: These findings suggest that an intensive behavioral modification intervention program, delivered to employees in a health care setting, results in significant short term benefit in weight reduction, increase fitness level and concomitantly improve cardio-metabolic risk profile. Further follow-up is in progress to ascertain whether these benefits are sustainable over a longer duration.

Computed Tomography of Adult Blunt Abdominal and Pelvic Trauma: Implications for Treatment and Interventions

Introduction Within the United States, trauma is the leading cause of death in children and adults between the ages of 1 and 44 years and the fourth largest cause of death across the entire US population. Blunt traumaticmechanisms account for 70% of all traumatic injury. Althoughmost blunt traumatic injury is related to motor vehicle collisions, blunt traumatic abdominal injury can also be seen in falls, assaults, and even medical techniques, such as the Heimlich maneuver or cardiopulmonary resuscitation. In blunt abdominal trauma, 3mechanisms are responsible for injury to abdominal organs and vasculature: deceleration, external compression, and crushing injuries. According to the American College of Radiology Appropriateness Criteria, patients who are hemodynamically unstable should not receive dedicated computed tomography (CT). In these patients, focused assessmentwith sonography for trauma (FAST) may be used in conjunction with chest and abdomen radiographs as part of a primary survey. FAST is useful in detecting abundant free intraperitoneal and pericardial fluid (blood) in hemodynamically unstable patients and can guide emergent surgery. Portable chest and abdomen radiographs typically complement FAST and serve to evaluate for abnormal gas or fluid collections, fractures, and position of lines and tubes in an unstable patient. Typically, unstable patients who do not respond to resuscitation undergo emergent surgical intervention without further imaging. However, in a hemodynamically stable patient (and increasingly, in a semistable patient), CT has become the standard for determining the extent of injury. Clinical examination and FAST notoriously underestimate intra-abdominal and pelvic injury, and missed injuries are a significant source of delayed morbidity and mortality. Nonsurgical management is the standard for all but

A large-scale, high-resolution hydrological model parameter data set for climate change impact assessment for the conterminous US

Abstract. To extend geographical coverage, refine spatial resolution, and improve modeling efficiency, a computation- and data-intensive effort was conducted to organize a comprehensive hydrologic data set with post-calibrated model parameters for hydro-climate impact assessment. Several key inputs for hydrologic simulation – including meteorologic forcings, soil, land class, vegetation, and elevation – were collected from multiple best-available data sources and organized for 2107 hydrologic subbasins (8-digit hydrologic units, HUC8s) in the conterminous US at refined 1/24° (~4 km) spatial resolution. Using high-performance computing for intensive model calibration, a high-resolution parameter data set was prepared for the macro-scale variable infiltration capacity (VIC) hydrologic model. The VIC simulation was driven by Daymet daily meteorological forcing and was calibrated against US Geological Survey (USGS) WaterWatch monthly runoff observations for each HUC8. The results showed that this new parameter data set may help reasonably simulate runoff at most US HUC8 subbasins. Based on this exhaustive calibration effort, it is now possible to accurately estimate the resources required for further model improvement across the entire conterminous US. We anticipate that through this hydrologic parameter data set, the repeated effort of fundamental data processing can be lessened, so that research efforts can emphasize the more challenging task of assessing climate change impacts. The pre-organized model parameter data set will be provided to interested parties to support further hydro-climate impact assessment.

An Empirical Analysis of Trade-Related Redistribution and the Political Viability of Free Trade

Even if free trade creates net welfare gains for a country as a whole, the associated distributional implications can undermine the political viability of free trade. We show that trade-related redistribution increases the political viability of free trade in the US. We do so by assessing the causal effect of expected redistribution associated with the US Trade Adjustment Assistance program on US Congressional voting behavior on eleven Free Trade Agreements (FTAs) between 2003 and 2011. We find that a one standard deviation increase in redistribution leads to more than a 3% point increase in the probability of voting in favor of an FTA for the median representative. In addition, a one standard deviation decrease in redistribution across the entire US would have precluded passage of two of the eleven FTAs in our sample.

US TFP growth and the contribution of changes in export and import prices to real income growth

Using recent data from the Bureau of Economic Analysis, the Bureau of Labour Statistics (BLS), the Board of Governors of the Federal Reserve System and the US Department of Agriculture, the paper calculates the multifactor productivity (MFP) Growth for an Extended Business Sector of the US economy for the years 1987–2011. The Extended Business Sector (EBS) consists of the entire US economy less the inputs used and outputs produced by the Public Administration sector and less the US housing sector. The study found that MFP growth in the EBS averaged 1.157 % per year, somewhat higher than BLS MFP growth in the Private Sector which averaged 0.962 % per year. The study also produced estimates of MFP where a net output concept was used. Finally, the effects of changes in the prices of US exports and imports on real income growth was calculated using a translog model based on the work of Diewert and Morrison and Kohli.

The impact of emission and climate change on ozone in the United States under representative concentration pathways (RCPs).

Dynamical downscaling was applied in this study to link the global climate-chemistry model Community Atmosphere Model (CAM-Chem) with the regional models Weather Research and Forecasting (WRF) Model and Community Multi-scale Air Quality (CMAQ). Two representative concentration pathway (RCP) scenarios (RCP 4.5 and RCP 8.5) were used to evaluate the climate impact on ozone concentrations in the 2050s. From the CAM-Chem global simulation results, ozone concentrations in the lower to mid-troposphere (surface to ~300 hPa), from mid- to high latitudes in the Northern Hemisphere, decreases by the end of the 2050s (2057-2059) in RCP 4.5 compared to present (2001-2004), with the largest decrease of 4-10 ppbv occurring in the summer and the fall; and an increase as high as 10 ppbv in RCP 8.5 resulting from the increased methane emissions. From the regional model CMAQ simulation results, under the RCP 4.5 scenario (2057-2059), in the summer when photochemical reactions are the most active, the large ozone precursor emissions reduction leads to the greatest decrease of downscaled surface ozone concentrations compared to present (2001-2004), ranging from 6 to 10 ppbv. However, a few major cities show ozone increases of 3 to 7 ppbv due to weakened NO titration. Under the RCP 8.5 scenario, in winter, downscaled ozone concentrations increase across nearly the entire continental US in winter, ranging from 3 to 10 ppbv due to increased methane emissions. More intense heat waves are projected to occur by the end of the 2050s in RCP 8.5, leading to a 0.3 ppbv to 2.0 ppbv increase (statistically significant except in the Southeast) of the mean maximum daily 8 h daily average (MDA8) ozone in nine climate regions in the US. Moreover, the upper 95% limit of MDA8 increase reaches 0.4 ppbv to 1.5 ppbv in RCP 4.5 and 0.6 ppbv to 3.2 ppbv in RCP 8.5. The magnitude differences of increase between RCP 4.5 and 8.5 also reflect that the increase of methane emissions may favor or strengthen the effect of heat waves.

Improving Survival in Acute Myeloid Leukemia: Pick the Best Subjects?

Improving Survival in Acute Myeloid Leukemia: Pick the Best Subjects?