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We present a study of photon statistics associated with high-order harmonic generation (HHG) involving one-mode and intermodal correlations of the high harmonic photons. The aim of the paper is to give insight into the nonclassical properties of high-order harmonic modes. To this end, we use a simplified model describing an elementary quantum emitter: the model of a two-level atom. While the material system is extremely simplified in this description, the conclusions and the methods may be generalized for more complex cases. Our primary interest is an effective model of HHG in which the exciting pulse is classical, and the harmonics are quantized, although we touch upon the more generalized, fully quantized model as well. Evolution of the Mandel-parameter, photon antibunching, squeezing and cross-correlations are calculated. Results imply that with respect to a single quantized emitter, nonclassicality of the harmonics is present: sub-Poissonian photon statistic and squeezing can characterize certain optical modes, while strong anticorrelation can also be present., 21 pages, 13 figures

The interaction of matter with a quantized electromagnetic mode is considered. Representing a strong exciting field, the mode is assumed to contain a large number of photons. As a result, the material response is highly nonlinear: the completely quantized description results in generation of high harmonics. In order to understand the essence of the physical processes that are involved, we consider a finite dimensional model for the material system. Using an appropriate description in phase space, this approach leads to a transparent picture showing that the interaction splits the initial, exciting coherent state into parts, and the rapid change of the populations of these parts (that are coherent states themselves) results in the generation of high-order harmonics as secondary radiation. The method we use is an application of the discrete lattice of coherent states that was introduced by J. von Neumann., 10 pages, 4 figures

Communication networks form the backbone of our society. Topology control algorithms optimize the topology of such communication networks. Due to the importance of communication networks, a topology control algorithm should guarantee certain required consistency properties (e.g., connectivity of the topology), while achieving desired optimization properties (e.g., a bounded number of neighbors). Real-world topologies are dynamic (e.g., because nodes join, leave, or move within the network), which requires topology control algorithms to operate in an incremental way, i.e., based on the recently introduced modifications of a topology. Visual programming and specification languages are a proven means for specifying the structure as well as consistency and optimization properties of topologies. In this paper, we present a novel methodology, based on a visual graph transformation and graph constraint language, for developing incremental topology control algorithms that are guaranteed to fulfill a set of specified consistency and optimization constraints. More specifically, we model the possible modifications of a topology control algorithm and the environment using graph transformation rules, and we describe consistency and optimization properties using graph constraints. On this basis, we apply and extend a well-known constructive approach to derive refined graph transformation rules that preserve these graph constraints. We apply our methodology to re-engineer an established topology control algorithm, kTC, and evaluate it in a network simulation study to show the practical applicability of our approach, This document corresponds to the accepted manuscript of the referenced journal article

The property graph data model of modern graph database systems is increasingly adapted for storing and processing heterogeneous datasets like networks. Many challenging applications with near real-time requirements -- e.g. financial fraud detection, recommendation systems, and on-the-fly validation -- can be captured with graph queries, which are evaluated repeatedly. To ensure quick response time for a changing data set, these applications would benefit from applying incremental view maintenance (IVM) techniques, which can perform continuous evaluation of queries and calculate the changes in the result set upon updates. However, currently, no graph databases provide support for incremental views. While IVM problems have been studied extensively over relational databases, views on property graph queries require operators outside the scope of standard relational algebra. Hence, tackling this problem requires the integration of numerous existing IVM techniques and possibly further extensions. In this paper, we present an approach to perform IVM on property graphs, using a nested relational algebraic representation for property graphs and graph operations. Then we define a chain of transformations to reduce most property graph queries to flat relational algebra and use techniques from discrimination networks (used in rule-based expert systems) to evaluate them. We demonstrate the approach using our prototype tool, ingraph, which uses openCypher, an open graph query language specified as part of an industry initiative. However, several aspects of our approach can be generalised to other graph query languages such as G-CORE and PGQL.

Brandon C. Varr, MD, Shirin Zarafshar, MD, Terra Coakley, MAT, Michaela Liedtke, MD, Richard A. Lafayette, MD, Sally Arai, MD, Stanley L. Schrier, MD, Ronald M. Witteles, MD From the Division of Cardiology, Columbia University Medical Center, New York, New York, Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford University School of Medicine, Stanford, California, Division of Hematology, Division of Nephrology; and Division of Blood and Marrow Transplantation, Stanford University School of Medicine, Stanford, California.

The CHADS 2 scoring system was found to be a good predictor for risk stratification of stroke in patients with atrial fibrillation. The effectiveness of this scoring system in assessing thrombogenic milieu before direct-current cardioversion has not yet fully been established on a large scale. In this study, data from 2,369 consecutive patients in whom transesophageal echocardiography was performed for screening before direct-current cardioversion from 1999 to 2008 were analyzed. Left atrial (LA) or LA appendage (LAA) thrombogenic milieu (spontaneous echo contrast, sludge, and thrombus) was investigated. The results were correlated with CHADS 2 score findings. The mean age was 66 ± 13 years, and the ratio of men to women was 2.2:1. CHADS 2 scores of 0, 1, 2, 3, 4, 5 and 6 were present in 11%, 25%, 30%, 22%, 8%, 3%, and 1% of the studies, respectively. The prevalence of LA or LAA sludge or thrombus increased with increasing CHADS 2 scores (2.3%, 7%, 8.5%, 9.9%, 12.3%, and 14.1% for scores of 0, 1, 2, 3, 4, and 5 or 6, respectively, p = 0.01). In a multivariate model, an ejection fraction ≤20% was the best predictor of LA or LAA sludge or thrombus (odds ratio 2.99, p 2 scores in patients who underwent transesophageal echocardiography–guided cardioversion. Giving more value to echocardiographic findings, such as the left ventricular ejection fraction, and its different levels (especially an ejection fraction ≤20%) might improve the precision of the CHADS 2 scoring scheme to predict thrombogenic milieu in the left atrium or LAA as a surrogate to cardioembolic risk in patients with atrial fibrillation.

Background Mechanical circulatory support (MCS) is increasingly used as a bridge to heart transplantation. It is not known whether patients who receive MCS as bridge to transplantation (BTT) have more frequent and severe infectious complications in the first transplant year. Methods Using a retrospective cohort in a single large transplant center from 2009 to 2014, we compared rates of post-transplant infections among patients bridged to transplantation with medical therapy ( n = 134) or MCS ( n = 178) over the first post-transplant year. Serious infections necessitated >14 days of continuous intravenous antibiotic therapy. Results Pre-transplant device infections were common in the MCS group (32.6%). The proportion of patients with any infection (74.2% vs 60.5%; p = 0.01, relative risk 1.23 [1.04 to 1.44]) or serious infections (45.5% vs 31.3%; p = 0.01, relative risk 1.45 [1.08 to 1.96]) in the first post-transplant year was significantly higher in the MCS group than in the medical therapy group, respectively. MCS patients but not medical therapy patients had significantly higher 1-year all-cause mortality in the presence of post-operative infections (16.7% vs 4.3%, p = 0.04). Device-related infections occurred in 67 (37.6%) MCS patients up to 337 days post-transplant, including 26 (14.6%) patients without a known or active pre-operative device infection. In multivariable analyses, age, intensive care unit length of stay, presence of pre-transplant device infection and use of an anti-thymocyte agent were associated with increased rates of infection. Conclusion More infectious complications are experienced by patients who receive MCS as BTT, with a significant occurrence of device-related infections. MCS patients with post-transplant infections have higher mortality at 1 year compared with uninfected MCS patients.

We investigate a two-level atom in the field of a strong laser pulse. The resulting time-dependent polarization is the source of a radiation the frequency components of which are essentially harmonics of the driving field's carrier frequency. The time evolution of this secondary radiation is analyzed in terms of the expectation values of the photon number operators for a large number of electromagnetic modes that are initially in the vacuum state. Our method is based on a multimode version of the Jaynes-Cummings-Paul model and can be generalized to different radiating systems as well. We show, that after the exciting pulse, the final distribution of the photon numbers is close to the conventional (Fourier transform-based) power spectrum of the secondary radiation. The details of the high harmonic spectra are also analyzed, for many-cycle excitations a clear physical interpretation can be given in terms of the Floquet quasi-energies. A first step towards the determination of the photon statistics of the HHG modes reveals states with slightly super-Poissonian distribution., 9 pages, 6 figures, v2: minor changes according to the suggestions of the PRA referee

The CHADS(2) (congestive heart failure, hypertension, age75 years, diabetes mellitus, stroke or transient ischemic attack [2 points]) scoring scheme has been found to be a good predictor of stroke risk in patients with nonvalvular atrial fibrillation (AF). However, the value of the CHADS(2) scoring system in the risk stratification of patients with AF who undergo direct-current cardioversion has not yet been specifically investigated. In this study, a subgroup of 541 patients from the Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) study who had AF for48 hours and planned to undergo transesophageal echocardiography before direct-current cardioversion were enrolled. Each patient had a CHADS(2) score calculated. Of the patients with CHADS(2) scores of 0, 14 (10%) were found to have left atrial appendage thrombi on transesophageal echocardiography. After 6 months of follow up, patients with CHADS(2) scores of 3 to 6 showed a significantly higher mortality rate in comparison with patients with lower CHADS(2) scores (4.3% vs 0.5%, p = 0.004), despite their similar prevalence of left atrial appendage thrombus and stroke (thrombus: 13.4% vs 11.6%, p = 0.60; stroke: 0% vs 0.3%, p = 0.70). In conclusion, the CHADS(2) scoring system may be useful for predicting short-term mortality risk in patients with AF receiving elective direct-current cardioversion. However, in the preprocedural risk assessment of these patients, the CHADS(2) scoring system is not reliable in predicting risk for left atrial appendage thrombus formation, especially in patients with low CHADS(2) scores.

The purpose of this study was to evaluate appropriateness of transesophageal echocardiography (TEE) before direct current cardioversion (DCC), investigate indications for TEE, and analyze if indications are predictive of outcome. According to American College of Cardiology Foundation/American Society of Echocardiography 2011 Appropriateness Criteria, TEE is appropriate in the evaluation of patients with atrial fibrillation (AF) to facilitate clinical decision making with regards to anticoagulation and/or DCC. However, it is unclear in which instances physicians utilize TEE. We reviewed 671 TEE studies in 604 AF patients (age 66 ± 13 years, 67% male) in which TEE was performed before DCC for left atrial thrombus (LAT)/sludge. Studies were divided by the main indication for TEE into the following 8 categories: 1) congestive heart failure (CHF)/hemodynamic compromise; 2) symptomatic; 3) new onset AF; 4) hospitalized and symptomatic; 5) high stroke risk; 6) subtherapeutic anticoagulation; 7) miscellaneous; and 8) inappropriate for TEE. The main indications for TEE before DCC were symptomatic (26.4%) and CHF/hemodynamic compromise (26.1%). We deemed 2.7% of the studies as inappropriate. LAT/sludge was found in 8.2% of studies. Incidence of LAT/sludge differed significantly between indications (p = 0.0021) and the highest incidences occurred in the high stroke risk (17.6%) and hospitalized and symptomatic (14.1%) categories. No LAT/sludge was found in the miscellaneous or inappropriate groups. Stroke occurred in 2.5% (n = 15) of all patients and in all groups except for miscellaneous and inappropriate (p = 0.3). TEE is appropriately used prior to DCC for patients with the main indications of symptomatic and CHF/hemodynamic compromise. In a minority of studies, TEE utilization was inappropriate. Incidence of LAT/sludge differed between indications.

Limited data exist regarding screening methods and outcomes for orthotopic heart transplantation (OHT) in cardiac amyloidosis. As a result, uncertainty exists over the best approach to OHT for cardiac amyloidosis and for the timing of critical post-transplant therapies. This article reviews 6 patients who underwent OHT for cardiac amyloidosis at the Stanford University Amyloid Center from 2008 to present. All patients with light-chain amyloidosis received chemotherapy in the interval between OHT and autologous hematopoietic stem cell transplant. Five patients remain alive up to 25 months after OHT, without evidence of recurrent cardiac amyloid deposition. A novel strategy of OHT, followed by light-chain suppressive chemotherapy before autologous hematopoietic stem cell transplant, is feasible for patients with light-chain amyloidosis.

This study evaluated the performance and feasibility of using open-path Fourier transform infrared (OP-FTIR) with a bi-beam strategy to assess personal exposures in workplaces. The bi-beam strategy combines a long beam and a short beam measurement to calculate the average concentration level of the segmented region. A series of experiments was conducted with six human subjects at two workstations inside a chamber. A bi-beam geometry was set up for each workstation. Each subject repeatedly performed two tasks (9 min/task), which were designed to simulate a painting and an assembly task. For each task a tracer gas (N(2)O) was released from a point source near the subject. During each task, while the OP-FTIR collected the N(2)O spectrum, bag samples were collected simultaneously at nose and lapel height. Statistical data analysis applied a general linear model with the bag samples as the dependent variable. Results show that the locations, tasks, and subjects are not significant factors when using OP-FTIR measurements with the bi-beam strategy to estimate personal exposure at the nose height. The model used in this study fits the data reasonably well (R(2)=0.87), and when it is compared with a second set of experimental data, the bias is 0.7 ppm (3%) and the precision is 5.5 ppm. This study demonstrates that the bi-beam sampling strategy may offer a new approach for applying OP-FTIR to industrial hygiene monitoring.

Acute heart failure (AHF) remains a major cause of morbidity and mortality, with an increasing prevalence anticipated over the next few decades as the population ages, heightening already significant health and economic burdens to society. New therapies for AHF have stalled over the past decade for a multitude of reasons, principal among them the heterogeneous population of patients affected with potentially multiple operative pathophysiologic mechanisms making a single targeted therapy a challenge. Serelaxin, a recombinant form of human relaxin-2, mediates adaptive cardiovascular effects during pregnancy that could be beneficial in the AHF population, primarily through nitric oxide-mediated vasodilation. Serelaxin is a novel therapeutic agent that has shown promise in the treatment of AHF in predefined subpopulations, though studies powered for "hard" outcomes are still pending. In this review, we examine the clinical investigations to date involving serelaxin in patients with heart failure and its possible emerging role in the future therapy of AHF.

The CHADS₂ scoring system was found to be a good predictor for risk stratification of stroke in patients with atrial fibrillation. The effectiveness of this scoring system in assessing thrombogenic milieu before direct-current cardioversion has not yet fully been established on a large scale. In this study, data from 2,369 consecutive patients in whom transesophageal echocardiography was performed for screening before direct-current cardioversion from 1999 to 2008 were analyzed. Left atrial (LA) or LA appendage (LAA) thrombogenic milieu (spontaneous echo contrast, sludge, and thrombus) was investigated. The results were correlated with CHADS₂ score findings. The mean age was 66 ± 13 years, and the ratio of men to women was 2.2:1. CHADS₂ scores of 0, 1, 2, 3, 4, 5 and 6 were present in 11%, 25%, 30%, 22%, 8%, 3%, and 1% of the studies, respectively. The prevalence of LA or LAA sludge or thrombus increased with increasing CHADS₂ scores (2.3%, 7%, 8.5%, 9.9%, 12.3%, and 14.1% for scores of 0, 1, 2, 3, 4, and 5 or 6, respectively, p = 0.01). In a multivariate model, an ejection fraction ≤20% was the best predictor of LA or LAA sludge or thrombus (odds ratio 2.99, p0.001). In conclusion, transesophageal echocardiographic markers of thrombogenic milieu were highly correlated with increasing CHADS₂ scores in patients who underwent transesophageal echocardiography-guided cardioversion. Giving more value to echocardiographic findings, such as the left ventricular ejection fraction, and its different levels (especially an ejection fraction ≤20%) might improve the precision of the CHADS₂ scoring scheme to predict thrombogenic milieu in the left atrium or LAA as a surrogate to cardioembolic risk in patients with atrial fibrillation.

When stratifying thromboembolic risk to patients with atrial fibrillation (AF), left atrial appendage (LAA) thrombus is currently the only echocardiographic index that absolutely contraindicates cardioversion. The aim of this study was to identify the predictors of LAA "sludge" and its impact on subsequent thromboembolism and survival in patients with AF.A total of 340 patients (mean age, 66 ± 12 years; 75% men) who underwent transesophageal echocardiography to exclude LAA thrombus before electrical cardioversion or radiofrequency pulmonary vein isolation) for AF were retrospectively studied. LAA sludge was defined as a dynamic, viscid, layered echodensity without a discrete mass, visualized throughout the cardiac cycle. Follow-up was obtained after a mean of 6.7 ± 3.7 years, and patients were analyzed according to LAA thrombus (n = 62 [18%]), sludge (n = 47 [14%]), or spontaneous echocardiographic contrast (n = 84 [25%]). Patients without these transesophageal echocardiographic characteristics served as controls (n = 147 [43%]).LAA sludge was independently predicted by enlarged left atrial area (odds ratio, 4.54; 95% confidence interval [CI], 2.38-8.67; P .001), reduced LAA emptying velocity (odds ratio, 12.7; 95% CI, 6.11-26.44; P .001), and reduced left ventricular ejection fraction (odds ratio, 2.11; 95% CI, 1.03-4.32; P .001). Thromboembolic event and all-cause mortality rates in patients with sludge were 23% and 57%, respectively. Multiple logistic regression analyses identified the presence of LAA sludge to be independently associated with thromboembolic complications (adjusted hazard ratio, 3.43; 95% CI, 1.42-8.28; P = .006) and all-cause mortality (adjusted hazard ratio, 2.02; 95% CI, 1.22-3.36; P = .007).Sludge within the LAA is independently associated with subsequent thromboembolic events and all-cause mortality in patients with AF.

Background: Little is known about the efficacy of shotgun eye protection. Shotguns can easily propel pellets with enough energy to penetrate the human eye, and a large percentage of shotgun eye injuries occur during shotgun sports such as hunting, trap, skeet, and sporting clays. Many of these injuries are preventable with proper eye protection. Although it is known that polycarbonate is the best lens material for shotgun eye protection, there has been no research that addresses the vision protective system design and its influence on eye protection. Methods: A field study was performed during which shotshells were fired at 1:1 scale photographs of human faces to determine the risk of ocular trauma. The protective efficacy of three types of polycarbonate protective eye wear (standard industrial safety glasses with snap-on side shields, wrap-around racket sport glasses, and three-piece glasses with integral side shields) was tested by firing shotshells at them at various distances. Both frontal and side protection was evaluated. Results: Results showed that the eye is at a high risk (55% to 100%) of being hit with shot pellets at ranges of 15 to 40 yards. It also was determined that the protective eye wear will give good frontal eye protection from shotgun pellets but integral side shields and a headband are necessary to obtain adequate side, protection. Conclusion: These findings, coupled with the poor visual prognosis of ocular shotgun injuries, indicate that polycarbonate protective eye wear with integral side shields and headbands should be worn by all involved with shotgun sports.