bluuebunny/crossref_metadata_2025 huggingface dataset:
SOME CONSTRUCTIONS OF ALMOST PARA-HYPERHERMITIAN STRUCTURES ON MANIFOLDS AND TANGENT BUNDLES
Authors: IANUŞ STERE , VÎLCU GABRIEL EDUARD
Published: September 2008

In this paper we give some examples of almost para-hyperhermitian structures on the tangent bundle of an almost product manifold, on the product manifold M × ℝ, where M is a manifold endowed with a mixed 3-structure and on the circle bundle over a manifold with a mixed 3-structure.
FRACTIONAL FIELD THEORIES FROM MULTI-DIMENSIONAL FRACTIONAL VARIATIONAL PROBLEMS
Authors: EL-NABULSI RAMI AHMAD
Published: September 2008

Fractional calculus has recently attracted considerable attention. In particular, various fractional differential equations are used to model nonlinear wave theory that arises in many different areas of physics such as Josephson junction theory, field theory, theory of lattices, etc. Thus one may expect fractional calculus, in particular fractional differential equations, plays an important role in quantum field theories which are expected to satisfy fractional generalization of Klein–Gordon and Dirac equations. Until now, in high-energy physics and quantum field theories the derivative operator has only been used in integer steps. In this paper, we want to extend the idea of differentiation to arbitrary non-integers steps. We will address multi-dimensional fractional action-like problems of the calculus of variations where fractional field theories and fractional differential Dirac operators are constructed.
BASICS OF QUANTUM MECHANICS, GEOMETRIZATION AND SOME APPLICATIONS TO QUANTUM INFORMATION
Authors: CLEMENTE-GALLARDO JESÚS , MARMO GIUSEPPE
Published: September 2008

In this paper we present a survey of the use of differential geometric formalisms to describe Quantum Mechanics. We analyze Schrödinger framework from this perspective and provide a description of the Weyl–Wigner construction. Finally, after reviewing the basics of the geometric formulation of quantum mechanics, we apply the methods presented to the most interesting cases of finite dimensional Hilbert spaces: those of two, three and four level systems (one qubit, one qutrit and two qubit systems). As a more practical application, we discuss the advantages that the geometric formulation of quantum mechanics can provide us with in the study of situations as the functional independence of entanglement witnesses.
A framework for the simulation of structural software evolution
Authors: Stopford Benjamin , Counsell Steve
Published: September 2008

As functionality is added to an aging piece of software, its original design and structure will tend to erode. This can lead to high coupling, low cohesion and other undesirable effects associated with spaghetti architectures. The underlying forces that cause such degradation have been the subject of much research. However, progress in this field is slow, as its complexity makes it difficult to isolate the causal flows leading to these effects. This is further complicated by the difficulty of generating enough empirical data, in sufficient quantity, and attributing such data to specific points in the causal chain. This article describes a framework for simulating the structural evolution of software. A complete simulation model is built by incrementally adding modules to the framework, each of which contributes an individual evolutionary effect. These effects are then combined to form a multifaceted simulation that evolves a fictitious code base in a manner approximating real-world behavior. We describe the underlying principles and structures of our framework from a theoretical and user perspective; a validation of a simple set of evolutionary parameters is then provided and three empirical software studies generated from open-source software (OSS) are used to support claims and generated results. The research illustrates how simulation can be used to investigate a complex and under-researched area of the development cycle. It also shows the value of incorporating certain human traits into a simulation—factors that, in real-world system development, can significantly influence evolutionary structures.
A Conversation with Steve Bourne, Eric Allman, and Bryan Cantrill
Authors: Stanik John
Published: September 2008

In part one of a two-part series, three Queue editorial board members discuss the practice of software engineering. In their quest to solve the next big computing problem or develop the next disruptive technology, software engineers rarely take the time to look back at the history of their profession. What’s changed? What hasn’t changed? In an effort to shed light on these questions, we invited three members of ACM Queue’s editorial advisory board to sit down and offer their perspectives on the continuously evolving practice of software engineering.
Flash Disk Opportunity for Server Applications
Authors: Gray Jim , Fitzgerald Bob
Published: September 2008

NAND flash densities have been doubling each year since 1996. Samsung announced that its 32-gigabit NAND flash chips would be available in 2007. This is consistent with Chang-gyu Hwang’s flash memory growth model1 that NAND flash densities will double each year until 2010. Hwang recently extended that 2003 prediction to 2012, suggesting 64 times the current density250 GB per chip. This is hard to credit, but Hwang and Samsung have delivered 16 times since his 2003 article when 2-GB chips were just emerging. So, we should be prepared for the day when a flash drive is a terabyte(!). As Hwang points out in his article, mobile and consumer applications, rather than the PC ecosystem, are pushing this technology.
Alterations in Transmural Myocardial Strain
Authors: Carlhäll Carl J. , Nguyen Tom C. , Itoh Akinobu , Ennis Daniel B. , Bothe Wolfgang , Liang David , Ingels Neil B. , Miller D. Craig
Published: September 2008

Background—

In asymptomatic patients with severe isolated mitral regurgitation (MR), identifying the onset of early left ventricular (LV) dysfunction can guide the timing of surgical intervention. We hypothesized that changes in LV transmural myocardial strain represent an early marker of LV dysfunction in an ovine chronic MR model.

Methods and Results—

Sheep were randomized to control (CTRL, n=8) or experimental (EXP, n=12) groups. In EXP, a 3.5- or 4.8-mm hole was created in the posterior mitral leaflet to generate “pure” MR. Transmural beadsets were inserted into the lateral and anterior LV wall to radiographically measure 3-dimensional transmural strains during systole and diastolic filling, at 1 and 12 weeks postoperatively. MR grade was higher in EXP than CTRL at 1 and 12 weeks (3.0 [2–4] versus 0.5 [0–2]; 3.0 [1–4] versus 0.5 [0-1], respectively, both
P
<0.001). At 12 weeks, LV mass index was greater in EXP than CTRL (201±18 versus 173±17 g/m
2
;
P
<0.01). LVEDVI increased in EXP from 1 to 12 weeks (
P
=0.015). Between the 1 and 12 week values, the change in BNP (−4.5±4.4 versus −3.0±3.6 pmol/L), PRSW (9±13 versus 23±18 mm Hg), tau (−3±11 versus −4±7 ms), and systolic strains was similar between EXP and CTRL. The changes in longitudinal diastolic filling strains between 1 and 12 weeks, however, were greater in EXP versus CTRL in the subendocardium (lateral: −0.08±0.05 versus 0.02±0.14; anterior: −0.10±0.05 versus −0.02±0.07, both
P
<0.01).

Conclusions—

Twelve weeks of ovine “pure” MR caused LV remodeling with early changes in LV function detected by alterations in transmural myocardial strain, but not by changes in BNP, PRSW, or tau.
CCR2-Mediated Antiinflammatory Effects of Endothelial Tetrahydrobiopterin Inhibit Vascular Injury-Induced Accelerated Atherosclerosis
Authors: Ali Ziad A. , Bursill Christina A. , Douglas Gillian , McNeill Eileen , Papaspyridonos Marianna , Tatham Amy L. , Bendall Jennifer K. , Akhtar Asim M. , Alp Nicholas J. , Greaves David R. , Channon Keith M.
Published: September 2008

Background—

Vascular injury results in loss of endothelial nitric oxide (NO), production of reactive oxygen species (ROS), and the initiation of an inflammatory response. Both NO and ROS modulate inflammation through redox-sensitive pathways. Tetrahydrobiopterin (BH4) is an essential cofactor for endothelial nitric oxide synthase (eNOS) that regulates enzymatic synthesis of either nitric oxide or ROS. We hypothesized that endothelial BH4 is an important regulator of inflammation and vascular remodeling.

Methods and Results—

Endothelium-targeted overexpression of GTP cyclohydrolase 1 (GCH), the rate limiting enzyme in BH4 synthesis, increased levels of tetrahydrobiopterin (BH4), reduced endothelial superoxide, improved eNOS coupling, and reduced vein graft atherosclerosis in transgenic GCH/ApoE-KO mice compared to ApoE-KO controls. Immunohistochemistry using anti-MAC-3 and MAC-1 antibody staining revealed a marked reduction in vein graft macrophage content, as did RT-PCR expression of macrophage marker CD68 mRNA levels in GCH/ApoE-KO mice. When we investigated the potential mediators of this reduction, we discovered that mRNA and protein levels of MCP-1 (CCL2) but not RANTES (CCL5) were significantly reduced in GCH/ApoE-KO aortic tissue. Consistent with this finding we found a decrease in CCR2-mediated, but not CCR5-mediated, chemotaxis in vascular tissue and plasma samples from GCH/ApoE-KO animals.

Conclusion—

Increased endothelial BH4 reduces vein graft neointimal hyperplasia and atherosclerosis through a reduction in vascular inflammation. These findings highlight the importance of MCP-1/CCR2 signaling in the response to vascular injury and identify novel pathways linking endothelial BH4 to inflammation and vascular remodeling.
Prediction of Cardiac Stability After Weaning From Left Ventricular Assist Devices in Patients With Idiopathic Dilated Cardiomyopathy
Authors: Dandel Michael , Weng Yuguo , Siniawski Henryk , Potapov Evgenij , Drews Thorsten , Lehmkuhl Hans B. , Knosalla Christoph , Hetzer Roland
Published: September 2008

Background—

During ventricular assist device (VAD) unloading, cardiac recovery is possible even in patients with chronic heart failure (HF). We sought parameters predictive of cardiac stability after VAD removal.

Methods and Results—

Among 81 patients weaned since March 1995, a homogenous group of 35 with idiopathic dilated cardiomyopathy weaned from left VADs was selected. We evaluated echo data obtained before left VAD implantation and during “off-pump” trials before explantation, histological changes, and serum anti-β1-adrenoceptor-autoantibody disappearance during unloading, duration of unloading, and HF duration. Postweaning 10-year survival with native hearts reached 70.7±9.2%. During the first 5 years, HF recurred in 13 patients (37.1%). Only 6 (17.1%) died after HF recurrence or noncardiac complications related to left VAD explantation. Comparison of patients with and without long-term cardiac stability showed that stable patients were younger, HF history and recovery time during unloading shorter, and preweaning left ventricular assessment revealed higher left ventricular ejection fraction, lower short/long axis ratios, and higher end diastolic relative wall thicknesses. For left ventricular ejection fraction ≥45% at end diastolic diameter of ≤55 mm, predictive value for ≥5-year cardiac stability was 87.5%. Left ventricular ejection fraction time course during the first 6 postweaning months appeared predictive for long-term stability. HF history >5 years and preweaning instability of cardiac improvement appeared predictive for HF recurrence.

Conclusions—

In idiopathic dilated cardiomyopathy, left VAD removal can be successful for >12 years even with incomplete cardiac recovery. Pre-explantation left ventricular ejection fraction, left ventricular end diastolic diameter and relative wall thicknesses, stability of unloading-induced cardiac recovery, duration of left VAD support, and HF duration before left VAD insertion allow identification of patients able to remain stable for >5 years. Time course of left ventricular ejection fraction during the first 6 postweaning months allows prognostic assessment.
Minimally Invasive Epicardial Injections Using a Novel Semiautonomous Robotic Device
Authors: Ota Takeyoshi , Patronik Nicholas A. , Schwartzman David , Riviere Cameron N. , Zenati Marco A.
Published: September 2008

Background—

We have developed a novel miniature robotic device (HeartLander) that can navigate on the surface of the beating heart through a subxiphoid approach. This study investigates the ability of HeartLander to perform in vivo semiautonomous epicardial injections on the beating heart.

Methods and Results—

The inchworm-like locomotion of HeartLander is generated using vacuum pressure for prehension of the epicardium and drive wires for actuation. The control system enables semiautonomous target acquisition by combining the joystick input with real-time 3-dimensional localization of the robot provided by an electromagnetic tracking system. In 12 porcine preparations, the device was inserted into the intrapericardial space through a subxiphoid approach. Ventricular epicardial injections of dye were performed with a custom injection system through HeartLander’s working channel. HeartLander successfully navigated to designated targets located around the circumference of the ventricles (mean path length=51±25 mm; mean speed=38±26 mm/min). Injections were successfully accomplished following the precise acquisition of target patterns on the left ventricle (mean injection depth=3.0±0.5 mm). Semiautonomous target acquisition was achieved within 1.0±0.9 mm relative to the reference frame of the tracking system. No fatal arrhythmia or bleeding was noted. There were no histological injuries to the heart due to the robot prehension, locomotion, or injection.

Conclusions–

In this proof-of-concept study, HeartLander demonstrated semiautonomous, precise, and safe target acquisition and epicardial injection on a beating porcine heart through a subxiphoid approach. This technique may facilitate minimally invasive cardiac cell transplantation or polymer therapy in patients with heart failure.
Long-Term Results of Heart Operations Performed by Surgeons-in-Training
Authors: Stoica Serban C. , Kalavrouziotis Dimitri , Martin Billie-Jean , Buth Karen J. , Hirsch Gregory M. , Sullivan John A. , Baskett Roger J.F.
Published: September 2008

Background—

We investigated the association between trainees performing supervised operations and late outcomes of patients undergoing cardiac surgery.

Methods and Results—

Data were prospectively collected on patients who underwent coronary artery bypass graft surgery, aortic valve replacement, or a combination of these between 1998 and 2005 at the Maritime Heart Center, Halifax, Canada. In-hospital mortality and a composite outcome of in-hospital mortality, stroke, bleeding, intra-aortic balloon pump insertion, renal failure, and sternal infection was compared between teaching (n=1054) and nonteaching cases (n=5877). Late survival and cardiovascular hospital readmissions were also examined. To adjust for baseline risk disparities, we used logistic regression for dichotomous in-hospital outcomes and Cox proportional hazards regression for survival data. Resident cases were significantly more likely to have high-risk features such as depressed ventricular function, redo operation, and urgent or emergent procedure. Resident as primary operator was not independently associated with in-hospital mortality (OR, 1.09; 95% CI, 0.75 to 1.58;
P
=0.66) or with the composite outcome (OR, 1.01; 95%, CI 0.82 to 1.26;
P
=0.90). The Kaplan-Meier event-free survival of the 2 groups was equivalent at 1, 3, and 5 years (log-rank
P
=0.06). By Cox regression, resident cases were not associated with late death or cardiovascular rehospitalization (hazard ratio, 1.05; 95% CI, 0.94 to 1.17;
P
=0.42).

Conclusions—

Cases performed by senior-level cardiac surgery residents were more likely to have greater acuity and complexity than staff surgeon-performed cases. However, clinical outcomes were similar in the short- and long-term. Allowing residents to perform cardiac surgery is not associated with adverse patient outcomes.
Endothelial Cell Coculture Within Tissue-Engineered Cardiomyocyte Sheets Enhances Neovascularization and Improves Cardiac Function of Ischemic Hearts
Authors: Sekine Hidekazu , Shimizu Tatsuya , Hobo Kyoko , Sekiya Sachiko , Yang Joseph , Yamato Masayuki , Kurosawa Hiromi , Kobayashi Eiji , Okano Teruo
Published: September 2008

Background—

Regenerative therapies, including myocardial tissue engineering, have been pursued as a new possibility to repair the damaged myocardium, and previously the transplantation of layered cardiomyocyte sheets has been shown to be able to improve cardiac function after myocardial infarction. We examined the effects of promoting neovascularization by controlling the densities of cocultured endothelial cells (ECs) within engineered myocardial tissues created using our cell sheet-based tissue engineering approach.

Methods and Results—

Neonatal rat cardiomyocytes were cocultured with GFP-positive rat-derived ECs on temperature-responsive culture dishes. Cocultured ECs formed cell networks within the cardiomyocyte sheets, which were preserved during cell harvest from the dishes using simple temperature reduction. We also observed significantly increased in vitro production of vessel-forming cytokines by the EC-positive cardiac cell sheets. After layering of 3 cardiac cell sheets to create 3-dimensional myocardial tissues, these patch-like tissue grafts were transplanted onto infarcted rat hearts. Four weeks after transplantation, recovery of cardiac function could be significantly improved by increasing the EC densities within the engineered myocardial tissues. Additionally, when the EC-positive cardiac tissues were transplanted to myocardial infarction models, we observed significantly greater numbers of capillaries in the grafts as compared with the EC-negative cell sheets. Finally, blood vessels originating from the engineered EC-positive cardiac tissues bridged into the infarcted myocardium to connect with capillaries of the host heart.

Conclusions—

In vitro engineering of 3-dimensional cardiac tissues with preformed EC networks that can be easily connected to host vessels can contribute to the reconstruction of myocardial tissue grafts with a high potential for cardiac function repair. These results indicate that neovascularization can contribute to improved cardiac function after the transplantation of engineered cardiac tissues.
Progesterone Induces Human Leukocyte Antigen-G Expression in Vascular Endothelial and Smooth Muscle Cells
Authors: Sheshgiri Rohit , Rao Vivek , Tumiati Laura C. , Xiao Rong , Prodger Jessica L. , Badiwala Mitesh , Librach Clifford , Delgado Diego H.
Published: September 2008

Background—

Human leukocyte antigen-G (HLA-G) expression in heart transplant patients has been negatively associated with acute cellular rejection and cardiac allograft vasculopathy. We assessed HLA-G expression in vascular human endothelial and smooth muscle cell cultures to determine if future therapeutic agents can be targeted toward inducing HLA-G expression to protect against allograft rejection and vasculopathy.

Methods and Results—

Human coronary artery endothelial, aortic endothelial, and coronary artery smooth muscle cell cultures were exposed to cytokines (interferon-γ or interleukin-10), hypoxia/reoxygenation stress, immunosuppressive agents (cyclosporine, sirolimus, or tacrolimus), or progesterone. HLA-G was not expressed by untreated, normoxic cells. Furthermore, maximal doses of interferon-γ, interleukin-10, cyclosporine, sirolimus, or tacrolimus, as well as exposure to hypoxia/reoxygenation, failed to induce HLA-G expression. HLA-G, which has previously not been detected in adult vascular endothelial and smooth muscle cells, was detected by enzyme-linked immunosorbent assay and flow cytometry in human coronary artery endothelial, human coronary aortic endothelial, and human coronary artery smooth muscle cultures after incubation with progesterone in a dose-dependent manner (
P
<0.001) with no change in cellular proliferation ability or viability. This effect was partially blocked in the presence of mifepristone, a progesterone receptor antagonist (human coronary artery endothelial: 48.8±15.6%; human coronary aortic endothelial: 59.5±9.5%; human coronary artery smooth muscle: 59.8±9.8% of control;
P
<0.05). Progesterone-induced HLA-G expression was not protective against hypoxia/reoxygenation injury.

Conclusions—

HLA-G is not expressed at baseline in vascular endothelial and smooth muscle cells but can be induced by exposure to progesterone. Although tightly regulated, induction of HLA-G expression in these cells may represent a promising and novel therapeutic strategy to protect against rejection and cardiac allograft vasculopathy after heart transplantation.
Comparison of Different Adult Stem Cell Types for Treatment of Myocardial Ischemia
Authors: van der Bogt Koen E.A. , Sheikh Ahmad Y. , Schrepfer Sonja , Hoyt Grant , Cao Feng , Ransohoff Katherine J. , Swijnenburg Rutger-Jan , Pearl Jeremy , Lee Andrew , Fischbein Michael , Contag Christopher H. , Robbins Robert C. , Wu Joseph C.
Published: September 2008

Background—

A comparative analysis of the efficacy of different cell candidates for the treatment of heart disease remains to be described. This study is designed to evaluate the therapeutic efficacy of 4 cell types in a murine model of myocardial infarction.

Methods and Results—

Bone marrow mononuclear cells (MN), mesenchymal stem cells (MSC), skeletal myoblasts (SkMb), and fibroblasts (Fibro) expressing firefly luciferase (Fluc) and green fluorescence protein (GFP) were characterized by flow cytometry, bioluminescence imaging (BLI), and luminometry. Female FVB mice (n=70) underwent LAD ligation and intramyocardially received one cell type (5×10
5
) or PBS. Cell survival was measured by BLI and by TaqMan PCR. Cardiac function was assessed by echocardiography and invasive hemodynamic measurements. Fluc expression correlated with cell number in all groups (r
2
>0.93). In vivo BLI revealed acute donor cell death of MSC, SkMb, and Fibro within 3 weeks after transplantation. By contrast, cardiac signals were still present after 6 weeks in the MN group, as confirmed by TaqMan PCR (
P
<0.01). Echocardiography showed significant preservation of fractional shortening in the MN group compared to controls (
P
<0.05). Measurements of left ventricular end-systolic/diastolic volumes revealed that the least amount of ventricular dilatation occurred in the MN group (
P
<0.05). Histology confirmed the presence of MN, although there was no evidence of transdifferentiation by donor MN into cardiomyocytes.

Conclusions—

This is the first study to show that compared to MSC, SkMB, and Fibro, MN exhibit a more favorable survival pattern, which translates into a more robust preservation of cardiac function.
Does Location of the Second Internal Thoracic Artery Graft Influence Outcome of Coronary Artery Bypass Grafting?
Authors: Sabik Joseph F. , Stockins Aleck , Nowicki Edward R. , Blackstone Eugene H. , Houghtaling Penny L. , Lytle Bruce W. , Loop Floyd D.
Published: September 2008

Background—

We sought to determine whether location of the second internal thoracic artery (ITA) graft used for bilateral ITA grafting affects mortality and morbidity of patients with 3-system coronary artery disease and to identify factors associated with second ITA location.

Methods and Results—

From January 1972 to June 2006, 3611 patients with 3-system coronary artery disease underwent bilateral ITA grafting with one graft anastomosed to the left anterior descending system and the second to either the circumflex (n=2926) or right coronary artery (n=685) system. Follow-up was 9.2±7.2 years. Propensity score methodology was used to obtain risk-adjusted outcome comparisons between patients with the second ITA to circumflex versus right coronary artery. Hospital mortality (0.34% versus 0.58%;
P
=0.4), stroke (0.96% versus 0.88%;
P
=0.8), myocardial infarction (1.3% versus 0.73%;
P
=0.2), renal failure (0.44% versus 0.29%;
P
=0.6), respiratory insufficiency (3.5% versus 3.8%;
P
=0.7), and reoperation for bleeding (3.4% versus 3.2%;
P
=0
.
8) were similar in patients who received the second ITA to circumflex or right coronary artery and remained similar after propensity score adjustment. Late survival (86% versus 87% at 10 years) was also similar. Despite this, there was a gradual decline in ITA to right coronary artery grafting.

Conclusions—

Contrary to prevailing wisdom that the second ITA graft should be anastomosed to the next most important left-sided coronary artery in 3-system coronary artery disease, it may be placed to either the circumflex or right coronary artery system with similar early and late outcomes.
A Factor Underlying Late-Phase Arrhythmogenicity After Cell Therapy to the Heart
Authors: Coppen Steven R. , Fukushima Satsuki , Shintani Yasunori , Takahashi Kunihiko , Varela-Carver Anabel , Salem Husein , Yashiro Kenta , Yacoub Magdi H. , Suzuki Ken
Published: September 2008

Background—

Arrhythmia occurrence is a variable but serious concern of cell therapy for treating heart failure. Using a rat postinfarction chronic heart failure model, we compared skeletal myoblast (SMB) with bone marrow cell (BMC) injection to highlight donor cell-specific, late-phase arrhythmogenesis and the underlying factors.

Methods and Results—

SMBs or BMCs derived from male GFP-transgenic rats, or PBS were injected intramyocardially into female rat hearts 3 weeks after coronary artery occlusion. At 28 days after injection, echocardiography showed that the left ventricular ejection fraction was significantly improved in both the SMB and BMC groups, compared to PBS control despite poor graft survival as assessed by PCR for the male-specific gene. Radio-telemetry analysis revealed that the SMB group displayed a higher occurrence of ventricular premature contractions with an elongation of the QRS complex and the hearts were more susceptible to isopreterenol-induced ventricular tachycardia compared to the BMC and PBS groups. Western blot and immunoconfocal analysis showed that the gap junction protein, connexin43, was widely and persistently decreased in the SMB group compared to the other groups. IL-1β was shown to be upregulated in hearts after SMB injection, and in vitro experiments demonstrated that exposure to IL-1β caused a decrease in connexin43 and intercellular communication in cultured cardiomyocytes.

Conclusions—

Although cell therapy was capable of improving function of the postinfarction chronically failing heart, there was late-phase arrhythmogenicity specific to donor cell type. Global downregulation of connexin43 in the host myocardium was indicated to be an important factor underlying late-phase arrhythmogenicity after SMB transplantation.
Survival After Resection of Primary Cardiac Tumors
Authors: ElBardissi Andrew W. , Dearani Joseph A. , Daly Richard C. , Mullany Charles J. , Orszulak Thomas A. , Puga Francisco J. , Schaff Hartzell V.
Published: September 2008

Background—

Primary cardiac tumors are rare but have the potential to cause significant morbidity if not treated in an appropriate and timely manner. To date, however, there have been no studies examining survival characteristics of patients who undergo surgical resection.

Methods and Results—

From 1957 to 2006, 323 consecutive patients underwent surgical resection of primary cardiac tumors; 163 (50%) with myxomas, 83 (26%) with papillary fibroelastomas, 18 (6%) with fibromas, 12 (4%) with lipomas, 28 (9%) with other benign primary cardiac tumors, and 19 (6%) with primary malignant tumors. Operative (30 day) mortality was 2% (n=6). Univariate analysis indicated that patients who underwent resection of fibromas and myxomas had superior survival characteristics in comparison to the remainder of tumor variants; these results were consistent after adjusting for age at surgery, year of surgery, and cardiovascular risk factors. Based on actuarial characteristics of the 2002 U.S. population, patients who underwent myxoma resection had survival characteristics that were not significantly different from that of an age and gender matched population (SMR 1.11,
P
=0.57) whereas those who underwent resection of fibromas (SMR 11.17,
P
=0.002), papillary fibroelastomas (SMR 3.17,
P
=0.0003), lipomas (SMR 5.0,
P
=0.0003), other benign tumors (SMR 4.63,
P
=0.003), and malignant tumors (SMR 101,
P
<0.0001) had significantly poorer survival characteristics. Furthermore, malignant tumors in younger patients were highly fatal (HR 0.899,
P
<0.0001). Although the most significant predictor of mortality was tumor histology, survival was also influenced the by the duration of CPB and NYHA III/IV; the impact of these risk factors varied with time. The cumulative incidence of myxoma recurrence was 13% and occurred in a younger population (42 versus 57 years,
P
=0.003) with the risk of recurrence decreased after 4 years.

Conclusions—

Surgical resection of primary cardiac tumors is associated with excellent long-term survival; patients with cardiac myxomas have survival characteristics that are not significantly different from that of a general population. Predictors of mortality are primarily related to tumor histology but also include clinical characteristics such as symptomatology and duration of CPB.
Serum Potassium and Clinical Outcomes in the Eplerenone Post–Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS)
Authors: Pitt Bertram , Bakris George , Ruilope Luis M. , DiCarlo Lorenzo , Mukherjee Robin
Published: September 2008

Background—

Aldosterone blockade is recommended for patients with congestive heart failure after acute myocardial infarction complicated by left ventricular systolic dysfunction; however, the perceived risk of hyperkalemia may limit implementation of this therapeutic approach. This subanalysis examined the relationship between eplerenone, serum potassium (K
+
), and clinical outcomes in the Eplerenone Post–Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS).

Methods and Results—

Hospitalized patients with congestive heart failure after acute myocardial infarction complicated by left ventricular systolic dysfunction (left ventricular ejection fraction ≤40%) treated with standard therapy were randomized 3 to 14 days after the acute myocardial infarction to additional treatment with eplerenone (25 to 50 mg/d; n=3319) or placebo (n=3313). Patients were excluded if baseline K
+
was >5.0 mEq/L or serum creatinine was >2.5 mg/dL. In patients receiving standard therapy, the addition of eplerenone resulted in a 4.4% absolute increase in the incidence of K
+
>5.5 mEq/L, a 1.6% increase of K
+
≥6.0 mEq/L, and a 4.7% absolute decrease in hypokalemia (K
+
<3.5 mEq/L). Four independent baseline predictors of hyperkalemia (defined as ≥6.0 mEq/L) were identified: potassium (K
+
greater than the median; 4.3 mEq/L), estimated glomerular filtration rate (≤60 mL · min
−1
· 1.73 m
−2
), history of diabetes mellitus, and prior use of antiarrhythmic agents. None of these independent baseline risk factors significantly impacted the cardiovascular benefit of eplerenone for reducing all-cause mortality.

Conclusions—

Use of selective aldosterone blockade with eplerenone within the dose range of 25 to 50 mg/d in post–acute myocardial infarction patients with heart failure and left ventricular systolic dysfunction who are treated with standard therapy improves outcomes without an excess of risk of hyperkalemia (≥6.0 mEq/L) when periodic monitoring of serum K
+
is instituted.
Dynamic Changes in Matrix Metalloprotienase Activity Within the Human Myocardial Interstitium During Myocardial Arrest and Reperfusion
Authors: Spinale Francis G. , Koval Christine N. , Deschamps Anne M. , Stroud Robert E. , Ikonomidis John S.
Published: September 2008

Background—

Past studies have clearly established that matrix metalloproteinases (MMPs) contribute to adverse myocardial remodeling with ischemia and reperfusion. However, these studies measured MMP levels in extracted samples, and therefore whether and to what degree actual changes in interstitial MMP activity occur within the human myocardium in the context of ischemia/reperfusion remained unknown.

Methods and Results—

The present study directly quantified MMP interstitial activity within the myocardium of patients (n=14) undergoing elective cardiac surgery during steady-state conditions, as well as during and following an obligatory period of myocardial arrest and reperfusion achieved by cardiopulmonary bypass. Interstitial MMP activity was continuously monitored using a validated MMP fluorogenic substrate, a microdialysis system placed within the myocardium, and in-line fluorescent detection system. MMP activity, as measured by fluorescent emission, reached a stable steady state level by 10 minutes after deployment of the microdialysis system. During initiation of cardiopulmonary bypass, MMP activity increased by 20% from baseline values (
P
<0.05), and then rapidly fell with cardiac arrest and longer periods of cardiopulmonary bypass. However, with restoration of myocardial blood flow and separation from cardiopulmonary bypass, MMP interstitial activity increased by over 30% from baseline (
P
<0.05).

Conclusions—

The present study directly demonstrated that MMP proteolytic activity exists within the human myocardial interstitium and is a dynamic process under conditions such as myocardial arrest and reperfusion.
Algorithms for Deterministic Incremental Dependency Parsing
Authors: Nivre Joakim
Published: September 2008

Parsing algorithms that process the input from left to right and construct a single derivation have often been considered inadequate for natural language parsing because of the massive ambiguity typically found in natural language grammars. Nevertheless, it has been shown that such algorithms, combined with treebank-induced classifiers, can be used to build highly accurate disambiguating parsers, in particular for dependency-based syntactic representations. In this article, we first present a general framework for describing and analyzing algorithms for deterministic incremental dependency parsing, formalized as transition systems. We then describe and analyze two families of such algorithms: stack-based and list-based algorithms. In the former family, which is restricted to projective dependency structures, we describe an arc-eager and an arc-standard variant; in the latter family, we present a projective and a non-projective variant. For each of the four algorithms, we give proofs of correctness and complexity. In addition, we perform an experimental evaluation of all algorithms in combination with SVM classifiers for predicting the next parsing action, using data from thirteen languages. We show that all four algorithms give competitive accuracy, although the non-projective list-based algorithm generally outperforms the projective algorithms for languages with a non-negligible proportion of non-projective constructions. However, the projective algorithms often produce comparable results when combined with the technique known as pseudo-projective parsing. The linear time complexity of the stack-based algorithms gives them an advantage with respect to efficiency both in learning and in parsing, but the projective list-based algorithm turns out to be equally efficient in practice. Moreover, when the projective algorithms are used to implement pseudo-projective parsing, they sometimes become less efficient in parsing (but not in learning) than the non-projective list-based algorithm. Although most of the algorithms have been partially described in the literature before, this is the first comprehensive analysis and evaluation of the algorithms within a unified framework.
Nuclear Stability in South Asia
Authors: Ganguly Sumit
Published: September 2008

An examination of the onset, evolution, and termination of the 1999 and 2001–02 crises between India and Pakistan suggests that nuclear deterrence is robust in South Asia. Even though the 1999 crisis erupted into a war, its scope and dimensions were carefully circumscribed. Despite its conventional capabilities, India chose not to cross the Line of Control (the de facto international border in the disputed state of Jammu and Kashmir), and it avoided horizontal escalation of the conflict. India's restraint cannot be attributed either to timely U.S. intervention or to a concern about avoiding a bellicose international image. Instead a highly jingoistic regime, which had defied international public opinion the previous year through a series of nuclear tests, chose to exercise restraint because of Pakistan's possession of nuclear weapons. In 2001, despite grave Pakistani provocation through a series of terrorist attacks, India could only respond with a strategy of coercive diplomacy.
The Temporal Response of the Length of a Partially Stratified Estuary to Changes in River Flow and Tidal Amplitude
Authors: Lerczak James A. , Geyer W. Rockwell , Ralston David K.
Published: September 2008

The temporal response of the length of a partially mixed estuary to changes in freshwater discharge Qf and tidal amplitude UT is studied using a 108-day time series collected along the length of the Hudson River estuary in the spring and summer of 2004 and a long-term (13.4 yr) record of Qf , UT, and near-surface salinity. When Qf was moderately high, the tidally averaged length of the estuary L5, here defined as the distance from the mouth to the up-estuary location where the vertically averaged salinity is 5 psu, fluctuated by more than 47 km over the spring–neap cycle, ranging from 28 to >75 km. During low flow periods, L5 varied very little over the spring–neap cycle and approached a steady length. The response is quantified and compared to predictions of a linearized model derived from the global estuarine salt balance. The model is forced by fluctuations in Qf and UT relative to average discharge Qo and tidal amplitude UTo and predicts the linear response time scale τ and the steady-state length Lo for average forcing. Two vertical mixing schemes are considered, in which 1) mixing is proportional to UT and 2) dependence of mixing on stratification is also parameterized. Based on least squares fits between L5 and estuary length predicted by the model, estimated τ varied by an order of magnitude from a period of high average discharge (Qo = 750 m3 s−1, τ = 4.2 days) to a period of low discharge (Qo = 170 m3 s−1, τ = 40.4 days). Over the range of observed discharge, Lo ∝ Qo−0.30±0.03, consistent with the theoretical scaling for an estuary whose landward salt flux is driven by vertical estuarine exchange circulation. Estimated τ was proportional to the discharge advection time scale (LoA/Qo, where A is the cross-sectional area of the estuary). However, τ was 3–4 times larger than the theoretical prediction. The model with stratification-dependent mixing predicted variations in L5 with higher skill than the model with mixing proportional to UT. This model provides insight into the time-dependent response of a partially stratified estuary to changes in forcing and explains the strong dependence of the amplitude of the spring–neap response on freshwater discharge. However, the utility of the linear model is limited because it assumes a uniform channel, and because the underlying dynamics are nonlinear, and the forcing Qf and UT can undergo large amplitude variations. River discharge, in particular, can vary by over an order of magnitude over time scales comparable to or shorter than the response time scale of the estuary.
The coproduction of organizational presence: A study of Médecins Sans Frontières in action
Authors: Cooren François , Brummans Boris H.J.M. , Charrieras Damien
Published: September 2008

In this article, we develop an analytical perspective to examine how an organization's mode of being is constituted and experienced through ongoing processes of communication. To show the use and implications of this perspective, we analyze how members and partners of Médecins Sans Frontières (MSF, a.k.a.`Doctors Without Borders'), a renowned humanitarian organization, coproduce and problematize the presence of their organization in the Democratic Republic of the Congo, Africa.
Indigestible Recipe: Rice, Chicken Wings, and International Financial Institutions
Authors: Gros Jean-Germain
Published: September 2008

Food riots in Haiti in early April 2008 brought to the attention of the international community the plight of the Haitians. These events are neither unique to Haiti nor the product of happenstance. Instead, policies imposed on Haiti by international financial institutions (i.e., the World Bank and International Monetary Fund) since the 1980s, such as currency devaluation and trade liberalization, had a “double whammy” negative impact: They negated Haitian agricultural performance and the capacity of the Haitian state to manage the economy, thus exacerbating the current food crisis.
In Other Sources
Authors: Konrad Moira , Trela Katherine , Fishley Kate , White James , Mazzotti Valerie , Itoi Madoka
Published: September 2008

This column provides brief summaries of transition-related articles published in 2007 in 23 other professional journals. The 49 articles included descriptive, experimental, and qualitative research as well as program descriptions, conceptual papers, and practitioner pieces. All areas of Kohler's taxonomy for transition programming were addressed: family involvement, interagency collaboration, program structure, student development, and student-focused planning.
Autoimmune-mediated atherothrombosis
Authors: Matsuura E , Lopez LR
Published: September 2008

Autoimmune vascular inflammation and oxidative stress (lipid peroxidation) are common in systemic autoimmune diseases and contribute to the oxidative modification of low-density lipoprotein (oxLDL) and oxLDL/β2GPI complex formation. Circulating oxLDL/β2GPI complexes have been detected in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). The presence of antibodies to oxLDL/β2GPI complexes indicates that these complexes are immunogenic, and the coexistence of complexes and antibodies has pointed to an active proatherogenic role in the development of autoimmune vascular complications. Immunohistochemical staining of atherosclerotic lesions suggest that these complexes are formed in the arterial wall and released into circulation. The in vitro macrophage uptake of oxLDL/β2GPI complexes was significantly increased in the presence of antiphospholipid antibodies, either β2GPI-dependent anticardiolipin or anti-β2GPI antibodies, suggesting that macrophage Fcγ receptors are involved in lipid intracellular influx and foam cell formation. These findings provide an explanation for the accelerated development of atherosclerosis seen in SLE and APS. The presence of circulating oxLDL/β2GPI complexes and IgG antibodies to these complexes indicate significant vascular injury and oxidative stress as well as an active role in autoimmune-mediated atherothrombosis.
Federal Policy Activity and the Mobilization of State Lobbying Organizations
Authors: Baumgartner Frank R. , Gray Virginia , Lowery David
Published: September 2008

The mobilization of organized interests is affected not only by social and economic “supply” factors but also by government-related “demand” factors. The authors assess the impact of government activity on the mobilization of interests by examining how federal policy activity stimulates lobbying activity in the states. Empirically, they do this by introducing the federal hearings data used by Leech et al. into the model of state lobbying registrations used by Gray et al. The authors find that congressional hearings in a particular issue area have significant—albeit complex— effects on the mobilization of state interest organizations in that same area.
Strange Bedfellows? Polarized Politics? The Quest for Racial Equity in Contemporary America
Authors: King Desmond S. , Smith Rogers M.
Published: September 2008

Some scholars see contemporary American politics as characterized by “strange bedfellows” on racial issues and by polarization driven by economic, not racial, views. The authors argue instead that on most issues with racial dimensions, political actors and institutions are aligned into two racial orders, one favoring “color-blind” policies and the other “race-conscious” measures. Coalitions on two issues—affirmative action in employment and majority-minority districting—are explored to support this “racial orders” thesis.
Time-fractional Diffusion of Distributed Order
Authors: Mainardi Francesco , Mura Antonio , Pagnini Gianni , Gorenflo Rudolf
Published: September 2008

The partial differential equation of Gaussian diffusion is generalized by using the time-fractional derivative of distributed order between 0 and 1, in both the Riemann-Liouville and the Caputo sense. For a general distribution of time orders we provide the fundamental solution, which is a probability density, in terms of an integral of Laplace type. The kernel depends on the type of the assumed fractional derivative, except for the single order case where the two approaches turn out to be equivalent. We consider in some detail two cases of order distribution: Double-order, and uniformly distributed order. Plots of the corresponding fundamental solutions and their variance are provided for these cases, pointing out the remarkable difference between the two approaches for small and large times.
Study of the Indoor Air Quality in Hospitals in South Chennai, India — Microbial Profile
Authors: Sudharsanam Suchithra , Srikanth Padma , Sheela Merline , Steinberg Ralf
Published: September 2008

A 3-month pilot study (February—April 2006) was conducted to determine the quality of indoor air in hospitals in the Tamil Nadu region of India and to characterize the predominant aerobic bacteria and fungi present. The main objectives were (1) to sample the indoor air of three different hospitals in Chennai for bioaerosols to generate baseline data using the Petri plate gravitational settling (passive) method of sampling; and (2) to isolate and identify potentially pathogenic organisms prevalent in the hospital environment. Indoor air samples were collected from various wards at the different hospitals and processed for the identification of various predominant bacteria and fungi. The overall counts of Gram-positive organisms were found to be higher than Gram-negative organisms. Of these isolates, Staphylococci and Micrococci were the predominant Gram-positive bacteria, while Klebsiella sp. and Pseudomonas sp. were the predominant potentially pathogenic Gram-negative bacteria isolated. Among yeasts and molds, Aspergillus niger and A. flavus were commonly isolated.
Measurement of Radon Exhalation Rate from Building Materials used in the southwest coastal region of India
Authors: Pereira Christa E. , Vaidyan V.K. , Jojo P.J. , Ramachandran T.V.
Published: September 2008

This paper presents the results of a sample survey carried out to study the radon profile and radon exhalation rate in commonly used building materials used for construction of dwellings around high background areas of south India. Simultaneously, radon concentrations were also measured using passive detector techniques. Experimental procedure used for the measurement was the track etch technique. Radon emanation rates from the building materials studied varied from 17.7—308 mBq · m-3 · h-1. Estimated exhalation rates have been compared with others found in the literature.