Energetic Particle Precipitation in the Atmosphere: Northern Hemisphere Variability and Transport

It is well understood that chemical processes in the stratosphere lead to the destruction of ozone (O3). Our interest in these processes is twofold: (1) stratospheric O3 shields the Earth from biologically harmful radiation, and (2) O3 is a radiatively active gas largely responsible for the temperature structure of the middle atmosphere. A subset of chemical processes that is particularly relevant to O3 consists of catalytic cycles. Catalysts destroy O3 without being depleted. The NOx (NO + NO2) catalytic cycle dominates in the middle stratosphere. One source of stratospheric NOx is energetic particle precipitation (EPP), which contributes to the stratospheric odd nitrogen (NOy) budget in the polar winter. Through interaction with O3, NOx created by EPP (EPP-NOx) has the potential to affect not only the composition of the middle atmosphere but, since O3 is a radiatively active gas, temperature and dynamics as well. This leads to the following science questions, which are the questions that motivated my dissertation: (1) How much EPP-NOx is transported to the stratosphere from year to year? (2) What are the important transport processes involved? The research described here focuses on answering the first question through quantification of the amount of EPP-NOx reaching the northern hemisphere stratosphere using satellite data and the second question through state-of-the-art climate simulations designed to elucidate the important transport mechanisms.</p

A decadal satellite record of gravity wave activity in the lower stratosphere to study polar stratospheric cloud formation

Atmospheric gravity waves yield substantial small-scale temperature fluctuations that can trigger the formation of polar stratospheric clouds (PSCs). This paper introduces a new satellite record of gravity wave activity in the polar lower stratosphere to investigate this process. The record is comprised of observations of the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite from January 2003 to December 2012. Gravity wave activity is measured in terms of detrended and noise-corrected 15 µm brightness temperature variances, which are calculated from AIRS channels that are the most sensitive to temperature fluctuations at about 17–32 km of altitude. The analysis of temporal patterns in the data set revealed a strong seasonal cycle in wave activity with wintertime maxima at mid- and high latitudes. The analysis of spatial patterns indicated that orography as well as jet and storm sources are the main causes of the observed waves. Wave activity is closely correlated with 30 hPa zonal winds, which is attributed to the AIRS observational filter. We used the new data set to evaluate explicitly resolved temperature fluctuations due to gravity waves in the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis. It was found that the analysis reproduces orographic and non-orographic wave patterns in the right places, but that wave amplitudes are typically underestimated by a factor of 2–3. Furthermore, in a first survey of joint AIRS and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) satellite observations, nearly 50 gravity-wave-induced PSC formation events were identified. The survey shows that the new AIRS data set can help to better identify such events and more generally highlights the importance of the process for polar ozone chemistry

The Paradox of Misaligned Profiling: Theory and Experimental Evidence

This paper implements an experimental test of a game-theoretic model of equilibrium profiling. Attackers choose a demographic “type” from which to recruit, and defenders choose which demographic types to search. Some types are more reliable than others in the sense of having a higher probability of carrying out a successful attack if they get past the security checkpoint. In a Nash equilibrium, defenders tend to profile by searching the more reliable attacker types more frequently, whereas the attackers tend to send less reliable types. Data from laboratory experiments with financially motivated human subjects are consistent with the qualitative patterns predicted by theory. However, we also find several interesting behavioral deviations from the theory

DeWitt Wallace Library Annual Report 2014-2015

Summary of library and media services activities for 2014-201

DeWitt Wallace Library Annual Report 2015-2016

Summary of library and media services activities for 2015-201

Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis.

Atmospheric gravity waves play a key role in the transfer of energy and momentum between layers of the Earth's atmosphere. However, nearly all Global Circulation Models (GCMs) seriously under-represent the momentum fluxes of gravity waves at latitudes near 60° S. This can result in modelled winter stratospheres that are unrealistically cold – a significant bias known as the "cold-pole problem". There is thus a need for measurements of gravity-wave fluxes near 60S to test and constrain GCMs. Such measurements are notoriously difficult, because they require 3-D observations of wave properties if the fluxes are to be estimated without using significant limiting assumptions. Here we use 3-D satellite measurements of stratospheric gravity waves from NASA's AIRS/Aqua instrument. We present the first extended application of a 3-D Stockwell transform (3DST) method to determine localised gravity-wave amplitudes, wavelengths and directions of propagation around the entire region of the Southern Ocean near 60° S during austral winter 2010. We first validate our method using a synthetic wave field and two case studies of real gravity waves over the Southern Andes and the island of South Georgia. A new technique to overcome wave amplitude attenuation problems in previous methods is also presented. We then characterise large-scale gravity-wave occurrence frequencies, directional momentum fluxes and short-timescale intermittency over the entire Southern Ocean. Our results show that highest wave-occurrence frequencies, amplitudes and momentum fluxes are observed in the stratosphere over the mountains of the Southern Andes and Antarctic Peninsula. However, we find that around 60–80 % of total zonal-mean momentum flux is located over the open Southern Ocean during June–August, where a large "belt" of increased wave-occurrence frequencies, amplitudes and fluxes is observed. Our results also suggest significant short-timescale variability of fluxes from both orographic and non-orographic sources in the region. A particularly striking result is a widespread convergence of gravity-wave momentum fluxes towards latitudes around 60° S from the north and south. We propose that this convergence, which is observed at nearly all longitudes during winter, accounts for a significant part of the under-represented flux in GCMs at these latitudes

Successful Implementation of a Perioperative Glycemic Control Protocol in Cardiac Surgery: Barrier Analysis and Intervention Using Lean Six Sigma

Although the evidence strongly supports perioperative glycemic control among cardiac surgical patients, there is scant literature to describe the practical application of such a protocol in the complex ICU environment. This paper describes the use of the Lean Six Sigma methodology to implement a perioperative insulin protocol in a cardiac surgical intensive care unit (CSICU) in a large academic hospital. A preintervention chart audit revealed that fewer than 10% of patients were admitted to the CSICU with glucose <200 mg/dL, prompting the initiation of the quality improvement project. Following protocol implementation, more than 90% of patients were admitted with a glucose <200 mg/dL. Key elements to success include barrier analysis and intervention, provider education, and broadening the project scope to address the intraoperative period

Liver-Targeting of Interferon-Alpha with Tissue-Specific Domain Antibodies

PMCID: PMC3581439This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

A decadal satellite record of gravity wave activity in the lower stratosphere to study polar stratospheric cloud formation

Atmospheric gravity waves yield substantial small-scale temperature fluctuations that can trigger the formation of polar stratospheric clouds (PSCs). This paper introduces a new satellite record of gravity wave activity in the polar lower stratosphere to investigate this process. The record comprises observations of the Atmospheric InfraRed Sounder (AIRS) aboard NASA's Aqua satellite during January 2003 to December 2012. Gravity wave activity is measured in terms of detrended and noise-corrected 15 μm brightness temperature variances, which are calculated from AIRS channels that are most sensitive to temperature fluctuations at about 17–32 km altitude. The analysis of temporal patterns in the data set revealed a strong seasonal cycle in wave activity with wintertime maxima at mid and high latitudes. The analysis of spatial patterns indicated that orography as well as jet and storm sources are the main cause of the observed waves. Wave activity is closely correlated with 30 hPa zonal winds, which is attributed to the AIRS observational filter. We used the new data set to evaluate explicitly resolved temperature fluctuations due to gravity waves in the European Centre for Medium-Range Weather Forecast (ECMWF) operational analysis. It was found that the analysis reproduces orographic and non-orographic wave patterns in the right places, but that wave amplitudes are typically underestimated by a factor of 2–3. Furthermore, in a first survey of joint AIRS and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) satellite observations nearly 50 gravity wave-induced PSC formation events were identified. The survey shows that the new AIRS data set can help to better identify such events and more generally highlights the importance of the process for polar ozone chemistry

Selective improvement of pulmonary arterial hypertension with a dual ETA/ETB receptors antagonist in the apolipoprotein E−/− model of PAH and atherosclerosis

Idiopathic pulmonary arterial hypertension (IPAH) is increasingly diagnosed in elderly patients who also have an increased risk of comorbid atherosclerosis. Apolipoprotein E deficient (ApoE-/-) mice develop atherosclerosis with severe PAH when fed a high-fat diet (HFD), and have increased levels of endothelin (ET)-1. ET-1 receptor antagonists (ERAs) are used for the treatment of PAH but less is known about whether ERAs are beneficial in atherosclerosis. We therefore examined whether treatment of HFD-ApoE-/- mice with macitentan, a dual ETA/ETB receptor antagonist, would have any effect on both atherosclerosis and PAH. ApoE-/- mice were fed chow or HFD for 8 weeks. After 4 weeks of HFD, mice were randomised to a 4-week treatment of macitentan by food (30mg/kg/day dual ETA/ETB antagonist), or placebo groups. Echocardiography and closed-chest right heart catheterisation were used to determine PAH phenotype and serum samples were collected for cytokine analysis. Thoracic aortas were harvested to assess vascular reactivity using wire myography, and histological analyses were performed on the brachiocephalic artery and aortic root to assess atherosclerotic burden. Macitentan treatment of HFD-fed ApoE-/- mice was associated with a beneficial effect on the PAH phenotype and led to an increase in endothelial-dependent relaxation in thoracic aortae. Macitentan treatment was also associated with a significant reduction in interleukin 6 (IL-6) concentration but there was no significant effect on atherosclerotic burden. Dual blockade of ETA/ETB receptors improves endothelial function and improves experimental PAH but had no significant effect on atherosclerosis