Contribution of the North Atlantic subtropical high to regional climate model (RCM) skill in simulating southeastern United States summer precipitation

© 2014, Springer-Verlag Berlin Heidelberg.This study assesses the skill of advanced regional climate models (RCMs) in simulating southeastern United States (SE US) summer precipitation and explores the physical mechanisms responsible for the simulation skill at a process level. Analysis of the RCM output for the North American Regional Climate Change Assessment Program indicates that the RCM simulations of summer precipitation show the largest biases and a remarkable spread over the SE US compared to other regions in the contiguous US. The causes of such a spread are investigated by performing simulations using the Weather Research and Forecasting (WRF) model, a next-generation RCM developed by the US National Center for Atmospheric Research. The results show that the simulated biases in SE US summer precipitation are due mainly to the misrepresentation of the modeled North Atlantic subtropical high (NASH) western ridge. In the WRF simulations, the NASH western ridge shifts 7° northwestward when compared to that in the reanalysis ensemble, leading to a dry bias in the simulated summer precipitation according to the relationship between the NASH western ridge and summer precipitation over the southeast. Experiments utilizing the four dimensional data assimilation technique further suggest that the improved representation of the circulation patterns (i.e., wind fields) associated with the NASH western ridge substantially reduces the bias in the simulated SE US summer precipitation. Our analysis of circulation dynamics indicates that the NASH western ridge in the WRF simulations is significantly influenced by the simulated planetary boundary layer (PBL) processes over the Gulf of Mexico. Specifically, a decrease (increase) in the simulated PBL height tends to stabilize (destabilize) the lower troposphere over the Gulf of Mexico, and thus inhibits (favors) the onset and/or development of convection. Such changes in tropical convection induce a tropical–extratropical teleconnection pattern, which modulates the circulation along the NASH western ridge in the WRF simulations and contributes to the modeled precipitation biases over the SE US. In conclusion, our study demonstrates that the NASH western ridge is an important factor responsible for the RCM skill in simulating SE US summer precipitation. Furthermore, the improvements in the PBL parameterizations for the Gulf of Mexico might help advance RCM skill in representing the NASH western ridge circulation and summer precipitation over the SE US.

Variation in pediatric traumatic brain injury outcomes in the United States.

OBJECTIVE: To ascertain the degree of variation, by state of hospitalization, in outcomes associated with traumatic brain injury (TBI) in a pediatric population. DESIGN: A retrospective cohort study of pediatric patients admitted to a hospital with a TBI. SETTING: Hospitals from states in the United States that voluntarily participate in the Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project. PARTICIPANTS: Pediatric (age ≤ 19 y) patients hospitalized for TBI (N=71,476) in the United States during 2001, 2004, 2007, and 2010. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Primary outcome was proportion of patients discharged to rehabilitation after an acute care hospitalization among alive discharges. The secondary outcome was inpatient mortality. RESULTS: The relative risk of discharge to inpatient rehabilitation varied by as much as 3-fold among the states, and the relative risk of inpatient mortality varied by as much as nearly 2-fold. In the United States, approximately 1981 patients could be discharged to inpatient rehabilitation care if the observed variation in outcomes was eliminated. CONCLUSIONS: There was significant variation between states in both rehabilitation discharge and inpatient mortality after adjusting for variables known to affect each outcome. Future efforts should be focused on identifying the cause of this state-to-state variation, its relationship to patient outcome, and standardizing treatment across the United States.

VINTAGE MODERNISM: EARLY EXPERIMENTALIST MUSIC FOR VIOLIN IN THE UNITED STATES

The historical narrative of concert music in the early twentieth century has focused a great deal on the influence of European composers as well as the American composers who went to Europe to study. Often overlooked, however, is the influence of an entire generation of composers working in the United States during that time period. These artists experimented with polyrhythm, polytonality, dissonant counterpoint, and a whole host of other musical techniques in order to express their perceptions of a changing world. Over the years, the new techniques became associated with various movements including futurism, experimentalism and ultramodernism. Regardless of label, these composers were some of the first to introduce the new musical styles to the listening public.The recitals that make up this dissertation explore the sound world of experimentalist composers working in the United States during the early twentieth century. Serving as the foundation of these recitals are all four of the violin sonatas by Charles Ives, the “grandfather” of modernist music whose financial support helped to foster a whole generation of American composers. Also prominently featured is the music of Henry Cowell. His Suite for Violin and Piano, Mosaic Quartet (String Quartet No. 3), and Quartet Euphometric demonstrate the composer's use of cluster tones, dissonant counterpoint, polymeter, and indeterminate form. Additional works by George Antheil, Leo Ornstein, Wallingford Riegger, Dane Rudhyar, Carl Ruggles, and Ruth Crawford (Seeger) highlight other approaches taken by members of the ultra-modernist movement. Rounding out the repertoire for these recitals are works by Johanna Beyer and Conlon Nancarrow, both of whom either worked with or were influenced by Cowell in some way. All of the pieces selected date roughly from 1900 to the mid 1930's. Thus, the purpose of these recitals is not to provide a comprehensive overview of each composer's development, but rather to examine the influence and interconnections of a specific cross-section of the musical landscape.

Thermodynamic and dynamic contributions to future changes in regional precipitation variance: focus on the Southeastern United States

© 2014, Springer-Verlag Berlin Heidelberg.The frequency and severity of extreme events are tightly associated with the variance of precipitation. As climate warms, the acceleration in hydrological cycle is likely to enhance the variance of precipitation across the globe. However, due to the lack of an effective analysis method, the mechanisms responsible for the changes of precipitation variance are poorly understood, especially on regional scales. Our study fills this gap by formulating a variance partition algorithm, which explicitly quantifies the contributions of atmospheric thermodynamics (specific humidity) and dynamics (wind) to the changes in regional-scale precipitation variance. Taking Southeastern (SE) United States (US) summer precipitation as an example, the algorithm is applied to the simulations of current and future climate by phase 5 of Coupled Model Intercomparison Project (CMIP5) models. The analysis suggests that compared to observations, most CMIP5 models (~60 %) tend to underestimate the summer precipitation variance over the SE US during the 1950–1999, primarily due to the errors in the modeled dynamic processes (i.e. large-scale circulation). Among the 18 CMIP5 models analyzed in this study, six of them reasonably simulate SE US summer precipitation variance in the twentieth century and the underlying physical processes; these models are thus applied for mechanistic study of future changes in SE US summer precipitation variance. In the future, the six models collectively project an intensification of SE US summer precipitation variance, resulting from the combined effects of atmospheric thermodynamics and dynamics. Between them, the latter plays a more important role. Specifically, thermodynamics results in more frequent and intensified wet summers, but does not contribute to the projected increase in the frequency and intensity of dry summers. In contrast, atmospheric dynamics explains the projected enhancement in both wet and dry summers, indicating its importance in understanding future climate change over the SE US. The results suggest that the intensified SE US summer precipitation variance is not a purely thermodynamic response to greenhouse gases forcing, and cannot be explained without the contribution of atmospheric dynamics. Our analysis provides important insights to understand the mechanisms of SE US summer precipitation variance change. The algorithm formulated in this study can be easily applied to other regions and seasons to systematically explore the mechanisms responsible for the changes in precipitation extremes in a warming climate.

The Impact of Worsening Heart Failure in the United States.

In-hospital worsening heart failure represents a clinical scenario wherein a patient hospitalized for acute heart failure experiences a worsening of their condition, requiring escalation of therapy. Worsening heart failure is associated with worse in-hospital and postdischarge outcomes. Worsening heart failure is increasingly being used as an endpoint or combined endpoint in clinical trials, as it is unique to episodes of acute heart failure and captures an important event during the inpatient course. While prediction models have been developed to identify worsening heart failure, there are no known FDA-approved medications associated with decreased worsening heart failure. Continued study is warranted.

The Irish hospitals sweepstake in the United States of America, 1930-1939

The Irish hospitals sweepstake was established by statute in the Irish Free State in 1930 to fund the state’s hospital service. The vast majority of tickets were sold outside Ireland, particularly in countries where such gambling was illegal at the time. Initially the largest market was in the United Kingdom, but following the introduction of restrictive legislation there in 1934, the promoters of the sweepstake turned their attentions to North America and after 1936 the United States became the largest source of contributions to the Irish sweep. This article examines a number of factors concerning the relationship of the Irish sweep with the USA, including: an effort to estimate the amount of money contributed to the sweep by Americans; the role of the Irish diaspora and of prominent republicans, including Joseph McGarrity and Connie Neenan, in the illegal ticket distribution network; the efforts of American Federal agencies and government departments to disrupt the sweepstake organisation in America; how the sweep was used by those who sought to legalise gambling in the USA; the attitudes of both the Irish and American governments to the sweep’s activities in America; and how the legalisation of gambling in America brought about the demise of the Irish sweep.