bluuebunny/crossref_metadata_2025 huggingface dataset:
Design trade-offs for search engine caching
Authors: Baeza-Yates Ricardo , Gionis Aristides , Junqueira Flavio P. , Murdock Vanessa , Plachouras Vassilis , Silvestri Fabrizio
Published: October 2008

In this article we study the trade-offs in designing efficient caching systems for Web search engines. We explore the impact of different approaches, such as static vs. dynamic caching, and caching query results vs. caching posting lists. Using a query log spanning a whole year, we explore the limitations of caching and we demonstrate that caching posting lists can achieve higher hit rates than caching query answers. We propose a new algorithm for static caching of posting lists, which outperforms previous methods. We also study the problem of finding the optimal way to split the static cache between answers and posting lists. Finally, we measure how the changes in the query log influence the effectiveness of static caching, given our observation that the distribution of the queries changes slowly over time. Our results and observations are applicable to different levels of the data-access hierarchy, for instance, for a memory/disk layer or a broker/remote server layer.
A Conversation with Steve Bourne, Eric Allman, and Bryan Cantrill
Authors: Stanik John
Published: October 2008

In the July/August 2008 issue of ACM Queue we published part one of a two-part discussion about the practice of software engineering. The goal was to gain some perspective on the tools, techniques, and methodologies that software engineers use in their daily lives. Three members of Queue’s editorial advisory board participated: Steve Bourne, Eric Allman, and Bryan Cantrill, each of whom has made significant and lasting real-world contributions to the field (for more information on each of the participants, see part one). In part two we rejoin their conversation as they discuss XP (Extreme Programming) and Agile.
Erlang for Concurrent Programming
Authors: Larson Jim
Published: October 2008

Erlang is a language developed to let mere mortals write, test, deploy, and debug fault-tolerant concurrent software. Developed at the Swedish telecom company Ericsson in the late 1980s, it started as a platform for developing soft realtime software for managing phone switches. It has since been open-sourced and ported to several common platforms, finding a natural fit not only in distributed Internet server applications, but also in graphical user interfaces and ordinary batch applications.
Parallel Programming with Transactional Memory
Authors: Drepper Ulrich
Published: October 2008

With the speed of individual cores no longer increasing at the rate we came to love over the past decades, programmers have to look for other ways to increase the speed of our ever-more-complicated applications. The functionality provided by the CPU manufacturers is an increased number of execution units, or CPU cores.
Review of "Eating the IT Elephant: Moving from Greenfield Development to Brownfield (1st ed.)," IBM Press, 2008, $29.99, ISBN: 0137130120.
Authors: Hill David G.
Published: October 2008

Review of "Eating the IT Elephant: Moving from Greenfield Development to Brownfield (1st ed.)," IBM Press, 2008, $29.99, ISBN: 0137130120.
Affine Romance
Authors: Kelly-Bootle Stan
Published: October 2008

There’s a British idiom, “Suck it and see,” the epitome of skepticism, which despite its coarse brevity could well replace whole libraries of posh philosophic bigtalk about the fabric of reality. A less aggressive version is “Show me, I’m from Missouri,” which requires the proper Southern Mizoorah drawl for maximum impact. Wherever you’re from, the message is one of eternal vigilance in the face of fancy claims. Advertising, the creation and pushing forth of fancy claims, predates human literacy, and its success is evident in many rampant domains ranging from religion and astrology to sugared water, pet rocks, and Java (only joking there, James).
MP1
Authors: Brosgol Ben
Published: October 2008

Level - Intermediate.

This intermediate-level tutorial is aimed at people with a technical background in software development. No previous experience with safety-critical standards is required. Some familiarity with one or more of C, C++, Ada, or Java would be useful.

Safety-critical systems (whose anomalous behavior could cause catastrophic or major failure involving loss of life) are becoming increasingly prevalent. Standards such as
DO-178B
, originally developed for commercial avionics, are attracting attention in other segments. The requirement to comply with such standards imposes constraints (on quality assurance, traceability, etc.) much beyond what is typical for Commercial-Off-The-Shelf Software. One of the major decisions that affects safety certification is the choice of programming language(s). Specific language features, either by their presence of absence, may make certification easier or harder. (Practicalities such as tool support and programmer experience are of course also important but are outside the scope of the tutorial).

This tutorial first summarizes existing safety standards, with a focus on DO-178B, and explains how they affect the requirements on a programming language. It specifically addresses the challenges imposed by Object-Oriented Technology and summarizes the work currently underway on DO-178C. The tutorial then assesses three language technologies - C (including C++), Ada, and Java - with respect to suitability for meeting these requirements through appropriate subsetting. MISRA C, SPARK, and the in-progress Safety-Critical Java Technology are specifically identified and reviewed.
Re-ADA
Authors: Liang Sheldon X. , Reibling Lyle A. , Betts John
Published: October 2008

Military commands must respond to a variety of situations by quickly assembling and organizing coalition forces consisting of different components from several countries. Dependable interoperability of their C4ISR systems is vital to the success of many military applications where pressing new requirements quickly emerge and undergo rapid change.

In order to achieve dependable interoperability, a reliable infrastructure is critical to incorporating operational components into C4ISR systems. Software architectures and related techniques hold the answer to interoperable, reliable and evolvable C4ISR systems. This paper analyzes the major aspects of dependable interoperability for C4ISR, and presents a Quantitative Interoperating Model (QIM) for enabling seamless interconnection, effective intercommunication and dependable interoperation between heterogeneous components over the network. Based on the QIM, an approach is synthesized toward Reliable Ada-based Descriptive Architecture (re-ADA) for C4ISR. As an executable architectural framework, re-ADA can directly be mapped into Ada95 code and constructed on the basis of CORBA to support distributed computing over-the-network. In particular, the well-formalized QIM - through mapping dependability into quantitative attributes that are attached to architectural artifacts - makes it possible to statically verify quantitative attributes during architectural design, and dynamically monitor them at runtime.
Ada and software engineering education
Authors: McCormick John W.
Published: October 2008

How do you select a programming language for your project? Few developers have the luxury of coding the same design in multiple languages to compare language merits. For over twenty years my undergraduate students have implemented the same large (10-15K lines), multi-tasking, real-time embedded system. In one 15 week semester, student teams specify, design, and implement software to control a substantial model railroad layout.

Students implement everything from device drivers for custom I/O hardware to high-level decision making algorithms. Student teams have implemented the project in both Ada and C. This paper describes the course, the laboratory, the project, and an analysis of the results achieved with each of the implementation languages.
Implementing the extended return statement for Ada 2005
Authors: Taft S. Tucker
Published: October 2008

Ada 2005 adds an important capability to the language by allowing the construction and return of an object of a limited type by a function. New syntax for an extended return statement was added to enhance this capability further. This capability to return newly constructed objects of a limited type from a function, when combined with the additional capability to use aggregates to construct objects of a limited type, goes a long way to making use of limited types far more friendly and effective.

Although the extended return statement and the associated ability to construct and return objects of a limited type brings new power to Ada, it also brings new choices and challenges to the Ada compiler implementor, when trying to decide how best to implement this feature. This presentation will review some of these alternatives, and present a high-level description of one particular approach based on the notion of an object creation context (OCC) which is designed to minimize the complexity of the generated code while providing an efficient and flexible implementation.
Removing backward go-to statements from Ada programs
Authors: Maurer Ward D.
Published: October 2008

We here apply a recent mathematical result to the design of a process for removing backward go-to statements from Ada programs. Such statements are often used by programmers whose only reasons to use Ada are contractual. The mathematical result involves directed graphs, such as the flow graphs of programs, and the first step in our algorithm involves constructing the flow graph of an Ada program. In the second step, this flow graph is rearranged according to our mathematical result, which specifies a linear order for every flow graph, together with a structure for it, of loops within loops, in which no loops overlap. In the third step, a new Ada program is produced from the rearranged flow graph. A problem arises here, within the syntax of Ada, which does not allow branching into a sequence of statements. We show how this problem must be addressed, even though addressing it can involve removing existing structure from the Ada program which we are processing.
Distributed status monitoring and controlusing remote buffers and Ada 2005
Authors: Moore Brad J.
Published: October 2008

The ability to monitor status and control equipment distributed over a network is a common network management need. This paper describes a relatively simple approach to designing a prototype dynamic network where the assets of all vehicles on the network can be monitored and controlled at multiple remote stations. In particular, Ada 2005 features are explored in conjunction with Ada's Distributed Systems Annex (DSA) features to utilize a suite of remote buffer classes that implement an interface providing a mechanism for sharing a distributed dataset. In addition, the paper demonstrates an approach for distributed interoperability between Ada and C++ by using the DSA to distribute a C++ class hierarchy of objects that can be accessed by application code written in both languages. Finally, the paper exposes a need and describes a possible solution for enhancing existing DSA implementations in order to provide better support for multicast networking solutions.
Anima
Authors: Doran Steven
Published: October 2008

Currently, embedded programs are written in a variety of programming languages. None were specifically designed for the real-time environment. The use of a general purpose language for embedded systems can lead to inefficient applications which are more likely to fail to meet timing and execution requirements, or experience run-time errors that prove catastrophic for safety-critical systems. A domain specific language, in which real-time constructs are part of the language proper rather than hosted in a library, is likely to lessen the risks of implementation of tasks with strict real-time requirements. This paper outlines a Ada derived programming language called Anima that directly addresses many of the challenging issues of real-time embedded software development.
A distributed, multi-language architecture for large unmanned ground vehicles
Authors: Cicalese Cynthia , Weatherly Richard , Sherrill Joel , Bolling Robert , Forbes Kevin , Grabowski Robert , Ring Keven , Seidel David
Published: October 2008

In this paper, we describe the design and development of a network of large unmanned ground vehicles (LUGVs) using low-cost, off-the-shelf technology and building upon experience gained at the 2005 Defense Advanced Research Projects Agency (DARPA) Grand Challenge. Our unique distributed architecture allows robots with different capabilities to interact, facilitates the use of multiple programming languages, and supports location and employment transparency of the interacting software agents. We wrote safety-critical and real-time software in Ada to benefit from the language's precise semantics and timing control, while writing navigation, maneuvering, user interaction, and visualization software in Java for rapid, flexible development.
Anti-Müllerian hormone levels reflect severity of PCOS but are negatively influenced by obesity: relationship with increased luteinizing hormone levels
Authors: Piouka Athanasia , Farmakiotis Dimitrios , Katsikis Ilias , Macut Djuro , Gerou Spiros , Panidis Dimitrios
Published: October 2008

The objective of the study was the comparison of anti-Müllerian hormone (AMH) levels among obese or overweight and normal-weight women with the four different polycystic ovary syndrome (PCOS) phenotypes and healthy control subjects. AMH levels were evaluated in four age- and body mass index (BMI)-matched groups of 25 normal-weight and 25 obese or overweight women each, belonging to the four main subsets of the syndrome resulting from combinations of the three diagnostic criteria [ group 1: oligo- and/or anovulation (ANOV), hyperandrogenemia (HA), and polycystic ovaries (PCO) on ultrasonographic evaluation; group 2: ANOV and HA; group 3: HA and PCO, group 4: ANOV and PCO], and in 50 (25 obese or overweight and 25 normal weight) age- and BMI-matched healthy control subjects. Age, BMI, waist circumference, FSH, LH, prolactin, testosterone, Δ4-androstenedione, dehydroepiandrosterone-sulfate, 17α-OH-progesterone, fasting insulin, glucose, AMH, free androgen index, and homeostasis model assessment for insulin resistance index were analyzed. AMH levels were significantly higher in PCOS groups 1 and 2 compared with groups 3 and 4 and the control group and higher in PCOS groups 3 and 4 compared with the control group. AMH levels were significantly increased in normal-weight compared with obese and overweight women. AMH concentrations were independently predicted, in order of significance, by LH and testosterone levels, BMI (negatively), and the total number of follicles 2–9 mm in diameter. The differences in circulating AMH levels between the main phenotypic groups of PCOS women appear to reflect the severity of the syndrome, but are negatively affected by obesity. Increased LH levels might be the most significant independent link between PCOS-associated disorders of ovulation and the observed increase in circulating AMH concentration.
System Level Evaluation of Innovative Coded MIMO-OFDM Systems for Broadcasting Digital TV
Authors: Nasser Y. , Hélard J.-F. , Crussière M.
Published: October 2008

Single-frequency networks (SFNs) for broadcasting digital TV is a topic of theoretical and practical interest for future broadcasting systems. Although progress has been made in the characterization of its description, there are still considerable gaps in its deployment with MIMO technique. The contribution of this paper is multifold. First, we investigate the possibility of applying a space-time (ST) encoder between the antennas of two sites in SFN. Then, we introduce a 3D space-time-space block code for future terrestrial digital TV in SFN architecture. The proposed 3D code is based on a double-layer structure designed for intercell and intracell space time-coded transmissions. Eventually, we propose to adapt a technique called effective exponential signal-to-noise ratio (SNR) mapping (EESM) to predict the bit error rate (BER) at the output of the channel decoder in the MIMO systems. The EESM technique as well as the simulations results will be used to doubly check the efficiency of our 3D code. This efficiency is obtained for equal and unequal received powers whatever is the location of the receiver by adequately combining ST codes. The 3D code is then a very promising candidate for SFN architecture with MIMO transmission.
Relations among Sums of Reciprocal Powers—Part II
Authors: Amigó José María
Published: October 2008

Some formulas relating the classical sums of reciprocal powers
are derived in a compact way by using generating functions. These relations
can be conveniently written by means of certain numbers which satisfy
simple summation formulas. The properties of the generating functions can
be further used to easily calculate several series involving the classical sums
of reciprocal powers.
Simulation of Boiling Flow Experiments Close to CHF with the Neptune_CFD Code
Authors: Končar Boštjan , Mavko Borut
Published: October 2008

A three-dimensional two-fluid code Neptune_CFD has been validated against the Arizona State University (ASU) and DEBORA boiling flow experiments. Two-phase flow processes in the subcooled flow boiling regime have been studied on ASU experiments. Within this scope a new wall function has been implemented in the Neptune_CFD code aiming to improve the prediction of flow parameters in the near-wall region. The capability of the code to predict the boiling flow regime close to critical heat flux (CHF) conditions has been verified on selected DEBORA experiments. To predict the onset of CHF regime, a simplified model based on the near-wall values of gas volume fraction was used. The results have shown that the code is able to predict the wall temperature increase and the sharp void fraction peak near the heated wall, which are characteristic phenomena for CHF conditions.
Semi‐automatic Integrated Segmentation Approaches and Contour Extraction Appliedto Computed Tomography Scan Images′
Authors: Khoodoruth B. Dhalila S. Y. , Rughooputh Harry C. S. , Lefer Wilfrid
Published: October 2008

We propose to segment two‐dimensional CT scans traumatic
brain injuries with various methods. These methods are
hybrid, feature extraction, level sets, region growing, and
watershed which are analysed based upon their parametric
and nonparametric arguments. The pixel intensities, gradient
magnitude, affinity map, and catchment basins of these
methods are validated based upon various constraints evaluations.
In this article, we also develop a new methodology for
a computational pipeline that uses bilateral filtering, diffusion
properties, watershed, and filtering with mathematical
morphology operators for the contour extraction of the lesion
in the feature available based mainly on the gradient
function. The evaluations of the classification of these lesions
are very briefly outlined in this context and are being
undertaken by pattern recognition in another paper work.
Robust Reservoir Generation by Correlation‐Based Learning
Authors: Yamazaki Tadashi , Tanaka Shigeru
Published: October 2008

Reservoir computing (RC) is a new framework for neural computation. A reservoir is usually a recurrent neural network with fixed random connections. In this article, we propose an RC model in which the connections in the reservoir are modifiable. Specifically, we consider correlation‐based learning (CBL), which modifies the connection weight between a given pair of neurons according to the correlation in their activities. We demonstrate that CBL enables the reservoir to reproduce almost the same spatiotemporal activity patterns in response to an identical input stimulus in the presence of noise. This result suggests that CBL enhances the robustness in the generation of the spatiotemporal activity pattern against noise in input signals. We apply our RC model to trace eyeblink conditioning. The reservoir bridged the gap of an interstimulus interval between the conditioned and unconditioned stimuli, and a readout neuron was able to learn and express the timed conditioned response.
Building Recurrent Neural Networks to Implement Multiple Attractor Dynamics Using the Gradient Descent Method
Authors: Namikawa Jun , Tani Jun
Published: October 2008

The present paper proposes a recurrent neural network model and learning algorithm that can acquire the ability to generate desired multiple sequences. The network model is a dynamical system in which the transition function is a contraction mapping, and the learning algorithm is based on the gradient descent method. We show a numerical simulation in which a recurrent neural network obtains a multiple periodic attractor consisting of five Lissajous curves, or a Van der Pol oscillator with twelve different parameters. The present analysis clarifies that the model contains many stable regions as attractors, and multiple time series can be embedded into these regions by using the present learning method.
Role of Microvolt T-Wave Alternans in Assessment of Arrhythmia Vulnerability Among Patients With Heart Failure and Systolic Dysfunction
Authors: Gold Michael R. , Ip John H. , Costantini Otto , Poole Jeanne E. , McNulty Steven , Mark Daniel B. , Lee Kerry L. , Bardy Gust H.
Published: October 2008

Background—

Sudden cardiac death remains a leading cause of mortality despite advances in medical treatment for the prevention of ischemic heart disease and heart failure. Recent studies showed a benefit of implantable cardioverter defibrillator implantation, but appropriate shocks for ventricular tachyarrhythmias were noted only in a minority of patients during 4 to 5 years of follow-up. Accordingly, better risk stratification is needed to optimize patient selection. In this regard, microvolt T-wave alternans (TWA) has emerged as a potentially useful measure of arrhythmia vulnerability, but it has not been evaluated previously in a prospective, randomized trial of implantable cardioverter defibrillator therapy.

Methods and Results—

This investigation was a prospective substudy of the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) that included 490 patients at 37 clinical sites. TWA tests were classified by blinded readers as positive (37%), negative (22%), or indeterminate (41%) by standard criteria. The composite primary end point was the first occurrence of any of the following events: sudden cardiac death, sustained ventricular tachycardia/fibrillation, or appropriate implantable cardioverter defibrillator discharge. During a median follow-up of 30 months, no significant differences in event rates were found between TWA-positive or -negative patients (hazard ratio 1.24, 95% confidence interval 0.60 to 2.59,
P
=0.56) or TWA-negative and nonnegative (positive and indeterminate) subjects (hazard ratio 1.28, 95% confidence interval 0.65 to 2.53,
P
=0.46). Similar results were obtained with the inclusion or exclusion of patients randomized to amiodarone in the analyses.

Conclusions—

TWA testing did not predict arrhythmic events or mortality in SCD-HeFT, although a small reduction in events (20% to 25%) among TWA-negative patients cannot be excluded given the sample size of this study. Accordingly, these results suggest that TWA is not useful as an aid in clinical decision making on implantable cardioverter defibrillator therapy among patients with heart failure and left ventricular systolic dysfunction.
Benefit of Oral Anticoagulant Over Antiplatelet Therapy in Atrial Fibrillation Depends on the Quality of International Normalized Ratio Control Achieved by Centers and Countries as Measured by Time in Therapeutic Range
Authors: Connolly Stuart J. , Pogue Janice , Eikelboom John , Flaker Gregory , Commerford Patrick , Franzosi Maria Grazia , Healey Jeffrey S. , Yusuf Salim
Published: October 2008

Background—

Oral anticoagulation (OAC) therapy is effective in atrial fibrillation but requires vigilance to maintain the international normalized ratio in the therapeutic range. This report examines how differences in time in therapeutic range (TTR) between centers and between countries affect the outcomes of OAC therapy.

Methods and Results—

In a posthoc analysis, the TTRs of patients on OAC in a randomized trial of OAC versus clopidogrel plus aspirin (Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events [ACTIVE W]) were used to calculate the mean TTR for each of 526 centers and 15 countries. Proportional-hazards analysis, with and without adjustment for baseline variables, was performed, with patients stratified by TTR quartile and country. A wide variation in TTRs was found between centers, with mean TTRs for centers in the 4 quartiles of 44%, 60%, 69%, and 78%. For patients at centers below the median TTR (65%), no treatment benefit was demonstrated as measured by relative risk for vascular events of clopidogrel plus aspirin versus OAC (relative risk, 0.93; 95% confidence interval, 0.70 to 1.24;
P
=0.61). However, for patients at centers with a TTR above the study median, OAC had a marked benefit, reducing vascular events by >2-fold (relative risk, 2.14; 95% confidence interval, 1.61 to 2.85;
P
<0.0001). Mean TTR also varied between countries from 46% to 78%; relative risk (clopidogrel plus aspirin versus OAC) varied from 0.6 to 3.6 (a 5-fold difference). A population-average model predicted that a TTR of 58% would be needed to be confident that patients would benefit from being on OAC.

Conclusions—

A wide variation exists in international normalized ratio control, as measured by TTR, between clinical centers and between countries, which has a major impact on the treatment benefit of OAC therapy. For centers and countries, a target threshold TTR exists (estimated between 58% and 65%) below which there appears to be little benefit of OAC over antiplatelet therapy.
Long-Term Trends in the Incidence of Heart Failure After Myocardial Infarction
Authors: Velagaleti Raghava S. , Pencina Michael J. , Murabito Joanne M. , Wang Thomas J. , Parikh Nisha I. , D'Agostino Ralph B. , Levy Daniel , Kannel William B. , Vasan Ramachandran S.
Published: October 2008

Background—

Although mortality after myocardial infarction (MI) has declined in the United States in recent decades, there have been few community-based investigations of the long-term trends in the incidence of heart failure after MI, and their results appear to be conflicting.

Methods and Results—

We evaluated 676 Framingham Heart Study participants between 45 and 85 years of age (mean age 67 years, 34% women) who developed a first MI between 1970 and 1999. We assessed the incidence rates of heart failure and of death without heart failure in each of 3 decades (1970 to 1979, 1980 to 1989, and 1990 to 1999). We estimated the multivariable-adjusted risk of events in the latter 2 decades, with the period 1970 to 1979 serving as the referent. The 30-day incidence of heart failure after MI rose from 10% in 1970 to 1979 to 23.1% in 1990 to 1999 (
P
for trend 0.003), whereas 30-day mortality after MI declined from 12.2% (1970 to 1979) to 4.1% (1990 to 1999). The 5-year incidence of heart failure after MI rose from 27.6% in 1970 to 1979 to 31.9% in 1990 to 1999 (
P
for trend 0.02), whereas 5-year mortality after MI declined from 41.1% (1970 to 1979) to 17.3% (1990 to 1999). In multivariable analyses, compared with the period 1970 to 1979, we observed higher 30-day (risk ratio 2.05, 95% confidence interval 1.25 to 3.36) and 5-year (risk ratio 1.74, 95% confidence interval 1.07 to 2.84) risks of heart failure in the decade 1990 to 1999. These trends were accompanied by lower 30-day (risk ratio 0.21, 95% confidence interval 0.09 to 0.47) and 5-year (risk ratio 0.31, 95% confidence interval 0.18 to 0.54) mortality rates in 1990 to 1999.

Conclusions—

In the present community-based sample, we observed an increase in the incidence of heart failure in recent decades that paralleled the decrease in mortality after MI.
Identification of Cardiac Troponin I Sequence Motifs Leading to Heart Failure by Induction of Myocardial Inflammation and Fibrosis
Authors: Kaya Ziya , Göser Stefan , Buss Sebastian J. , Leuschner Florian , Öttl Renate , Li Jin , Völkers Mirko , Zittrich Stefan , Pfitzer Gabriele , Rose Noel R. , Katus Hugo A.
Published: October 2008

Background—

Despite the widespread use of cardiac troponins for diagnosis of myocyte injury and risk stratification in acute cardiac disorders, little is known about the long-term effects of the released troponins on cardiac function. Recently, we showed that an autoimmune response to cardiac troponin I (cTnI) induces severe inflammation and subsequent fibrosis in the myocardium. This autoimmune disorder predisposes to heart failure and cardiac death in mice.

Methods and Results—

To investigate the role of cTnI-specific T cells, T cells were isolated from splenocytes of mice immunized with murine cTnI (mcTnI). Wild-type mice that received mcTnI-specific T cells showed high mcTnI-specific antibody titers, increased production of the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α, severe inflammation and fibrosis in the myocardium, and reduced fractional shortening. To identify the antigenic determinants of troponin I responsible for the observed inflammation, fibrosis, and heart failure, 16 overlapping 16mer to 18mer peptides covering the entire amino acid sequence of mcTnI (211 residues) were synthesized. Only mice immunized with residues 105 to 122 of mcTnI developed significant inflammation and fibrosis in the myocardium, with increased expression of the inflammatory chemokines RANTES, monocyte chemotactic protein-1, macrophage inflammatory protein-1α, macrophage inflammatory protein-1β, macrophage inflammatory protein-2, T-cell activation-3, and eotaxin and the chemokine receptors CCR1, CCR2, and CCR5. Mice immunized with the corresponding human cTnI residues 104 to 121 and the mcTnI residues 131 to 148 developed milder disease.

Conclusions—

Transfer of troponin I–specific T cells can induce inflammation and fibrosis in wild-type mice, which leads to deterioration of contractile function. Furthermore, 2 sequence motifs of cTnI that induce inflammation and fibrosis in the myocardium are characterized.
Renin Inhibition Improves Cardiac Function and Remodeling After Myocardial Infarction Independent of Blood Pressure
Authors: Westermann Dirk , Riad Alexander , Lettau Olga , Roks Anton , Savvatis Konstantinos , Becher Peter Moritz , Escher Felicitas , Jan Danser A.H. , Schultheiss Heinz-Peter , Tschöpe Carsten
Published: October 2008

Pharmacological renin inhibition with aliskiren is an effective antihypertensive drug treatment, but it is currently unknown whether aliskiren is able to attenuate cardiac failure independent of its blood pressure–lowering effects. We investigated the effect of aliskiren on cardiac remodeling, apoptosis, and left ventricular (LV) function after experimental myocardial infarction (MI). C57J/bl6 mice were subjected to coronary artery ligation and were treated for 10 days with vehicle or aliskiren (50 mg/kg per day via an SC osmopump), whereas sham-operated animals served as controls. This dose of aliskiren, which did not affect systemic blood pressure, improved systolic and diastolic LV function, as measured by the assessment of pressure-volume loops after MI. Furthermore, after MI LV dilatation, cardiac hypertrophy and lung weights were decreased in mice treated with aliskiren compared with placebo-treated mice after MI. This was associated with a normalization of the mitogen-activated protein kinase P38 and extracellular signal-regulated kinases 1/2, AKT, and the apoptotic markers bax and bcl-2 (all measured by Western blots), as well as the number of TUNEL-positive cells in histology. LV dilatation, as well as the associated upregulation of gene expression (mRNA abundance) and activity (by zymography) of the cardiac metalloproteinase 9 in the placebo group after MI, was also attenuated in the aliskiren-treated group. Aliskiren improved LV dysfunction after MI in a dose that did not affect blood pressure. This was associated with the amelioration of cardiac remodelling, hypertrophy, and apoptosis.
Evaluation of Turbulence Closure Models for Large-Eddy Simulation over Complex Terrain: Flow over Askervein Hill
Authors: Chow Fotini Katopodes , Street Robert L.
Published: October 2008

The evaluation of turbulence closure models for large-eddy simulation (LES) has primarily been performed over flat terrain, where comparisons with theory and observations are simplified. The authors have previously developed improved closure models using explicit filtering and reconstruction, together with a dynamic eddy-viscosity model and a near-wall stress term. This dynamic reconstruction model (DRM) is a mixed model, combining scale-similarity and eddy-viscosity components. The DRM gave improved results over standard eddy-viscosity models for neutral boundary layer flow over flat but rough terrain, yielding the expected logarithmic velocity profiles near the wall. The results from the studies over flat terrain are now extended to flow over full-scale topography. The test case is flow over Askervein Hill, an isolated hill in western Scotland, where a field campaign was conducted in 1983 with the purpose of capturing wind data representing atmospheric episodes under near-neutral stratification and steady wind conditions. This widely studied flow provides a more challenging test case for the new turbulence models because of the sloping terrain and separation in the lee of the hill. Since an LES formulation is used, a number of simulation features are different than those typically used in the Askervein literature. The simulations are inherently unsteady, the inflow conditions are provided by a separate turbulent flow database, and (uniquely herein) ensemble averages of the turbulent flow results are used in comparisons with field data. Results indicate that the DRM can improve the predictions of flow speedup and especially turbulent kinetic energy (TKE) over the hill when compared with the standard TKE-1.5 model. This is the first study, to the authors’ knowledge, in which explicit filtering and reconstruction (scale similarity) and dynamic turbulence models have been applied to full-scale simulations of the atmospheric boundary layer over terrain. Simulations with the lowest level of reconstruction are straightforward. Increased levels of reconstruction, however, present difficulties when used with a dynamic eddy-viscosity model. An alternative mixed model is proposed to avoid the complexities associated with the dynamic procedure and to allow higher levels of reconstruction; this mixed model combines a standard TKE-1.5 eddy-viscosity closure with velocity reconstruction to form a simple and efficient turbulence model that gives good results for both mean flow and turbulence over Askervein Hill. The results indicate that significant improvements in LES over complex terrain can be obtained by the use of mixed models that combine scale-similarity and eddy-viscosity components.
Zonal Flow Regime Changes in a GCM and in a Simple Quasigeostrophic Model: The Role of Stratospheric Dynamics
Authors: Bordi Isabella , Fraedrich Klaus , Ghil Michael , Sutera Alfonso
Published: October 2008

The atmospheric general circulation is characterized by both single- and double-jet patterns. The double-jet structure of the zonal mean zonal wind is analyzed in Southern Hemisphere observations for the two calendar months of November and April. The observed features are studied further in an idealized quasigeostrophic and a simplified general circulation model (GCM). Results suggest that capturing the bimodality of the zonal mean flow requires the parameterization of momentum and heat fluxes associated with baroclinic instability of the three-dimensional fields.

The role of eddy heat fluxes in generating the observed double-jet pattern is ascertained by using an analytical Eady model with stratospheric easterlies, in which a single wave disturbance interacts with the mean flow. In this model, the dual jets are generated by the zonal mean flow correction. Sensitivity of the results to the tropospheric vertical wind shear (or, equivalently, the meridional temperature gradient in the basic state’s troposphere) is also studied in the Eady model and compared to related experiments using the simplified GCM.
Predictability of Rotating Stratified Turbulence
Authors: Ngan K. , Bartello P. , Straub D. N.
Published: October 2008

Although predictability represents one of the fundamental problems in atmospheric science, gaps in our knowledge remain. Theoretical understanding of the inverse error cascade is limited mostly to homogeneous, isotropic turbulence, whereas numerical simulations have focused on highly complex numerical weather prediction models. These results cannot be easily reconciled.

This paper describes selected aspects of the predictability behavior of rotating stratified turbulence. The objective is to determine how the predictability varies with scale when the dynamics are more realistic than the idealized models that underlie the classical picture of predictability and yet are free of the parameterizations that complicate interpretation of NWP models. Using a numerical model of the nonhydrostatic Boussinesq equations, it is shown that the predictability decay, as diagnosed by the relative error, is slower for subsynoptic flow. The dependence on the deformation radius, differences between balanced and unbalanced modes, and implications for NWP models are discussed.
Evaluation of MJO Forecast Skill from Several Statistical and Dynamical Forecast Models
Authors: Seo Kyong-Hwan , Wang Wanqiu , Gottschalck Jon , Zhang Qin , Schemm Jae-Kyung E. , Higgins Wayne R. , Kumar Arun
Published: October 2008

This work examines the performance of Madden–Julian oscillation (MJO) forecasts from NCEP’s coupled and uncoupled general circulation models (GCMs) and statistical models. The forecast skill from these methods is evaluated in near–real time. Using a projection of El Niño–Southern Oscillation (ENSO)-removed variables onto the principal patterns of MJO convection and upper- and lower-level circulations, MJO-related signals in the dynamical model forecasts are extracted. The operational NCEP atmosphere–ocean fully coupled Climate Forecast System (CFS) model has useful skill (>0.5 correlation) out to ∼15 days when the initial MJO convection is located over the Indian Ocean. The skill of the CFS hindcast dataset for the period from 1995 to 2004 is nearly comparable to that from a lagged multiple linear regression model, which uses information from the previous five pentads of the leading two principal components (PCs). In contrast, the real-time analysis for the MJO forecast skill for the period from January 2005 to February 2006 using the lagged multiple linear regression model is reduced to ∼10–12 days. However, the operational CFS forecast for this period is skillful out to ∼17 days for the winter season, implying that the coupled dynamical forecast has some usefulness in predicting the MJO compared to the statistical model.

It is shown that the coupled CFS model consistently, but only slightly, outperforms the uncoupled atmospheric model (by one to two days), indicating that only limited improvement is gained from the inclusion of the coupled air–sea interaction in the MJO forecast in this model. This slight improvement may be the result of the existence of a propagation barrier around the Maritime Continent and the far western Pacific in the NCEP Global Forecast System (GFS) and CFS models, as shown in several previous studies. This work also suggests that the higher horizontal resolution and finer initial data might contribute to improving the forecast skill, presumably as a result of an enhanced representation of the Maritime Continent region.
An Analysis of ENSO Prediction Skill in the CFS Retrospective Forecasts
Authors: Wu Renguang , Kirtman Ben P. , van den Dool Huug
Published: October 2008

The present study documents the so-called spring prediction and persistence barriers in association with El Niño–Southern Oscillation (ENSO) in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFS) retrospective forecasts. It is found that the spring prediction and persistence barriers in the eastern equatorial Pacific sea surface temperature (SST) are preceded by a boreal winter barrier in the western equatorial Pacific zonal wind stress. The time of the persistence barrier is closely related to the time of the ENSO phase transition, but may differ from the time of the lowest variance. The seasonal change of the signal-to-noise ratio cannot explain the persistence barrier. While the noise may lead to a drop of skill around boreal spring in the western equatorial Pacific zonal wind stress, its impacts on the skill of eastern equatorial Pacific SST is small. The equatorial Pacific zonal winds display an excessive response to ENSO-related SST anomalies, which leads to a longer persistence in the equatorial Pacific thermocline depth anomalies and a delayed transition of the eastern equatorial Pacific SST anomalies. This provides an interpretation for the prediction skill drop in boreal spring in the eastern equatorial Pacific SST. The results suggest that improving the atmospheric model wind response to SST anomalies may reduce the spring prediction barrier.
A Finite-Volume Icosahedral Shallow-Water Model on a Local Coordinate
Authors: Lee Jin-Luen , MacDonald Alexander E.
Published: October 2008

An icosahedral-hexagonal shallow-water model (SWM) on the sphere is formulated on a local Cartesian coordinate based on the general stereographic projection plane. It is discretized with the third-order Adam–Bashforth time-differencing scheme and the second-order finite-volume operators for spatial derivative terms. The finite-volume operators are applied to the model variables defined on the nonstaggered grid with the edge variables interpolated using polynomial interpolation. The projected local coordinate reduces the solution space from the three-dimensional, curved, spherical surface to the two-dimensional plane and thus reduces the number of complete sets of basis functions in the Vandermonde matrix, which is the essential component of the interpolation. The use of a local Cartesian coordinate also greatly simplifies the mathematic formulation of the finite-volume operators and leads to the finite-volume integration along straight lines on the plane, rather than along curved lines on the spherical surface. The SWM is evaluated with the standard test cases of Williamson et al. Numerical results show that the icosahedral SWM is free from Pole problems. The SWM is a second-order finite-volume model as shown by the truncation error convergence test. The lee-wave numerical solutions are compared and found to be very similar to the solutions shown in other SWMs. The SWM is stably integrated for several weeks without numerical dissipation using the wavenumber 4 Rossby–Haurwitz solution as an initial condition. It is also shown that the icosahedral SWM achieves mass conservation within round-off errors as one would expect from a finite-volume model.
How Do Ideas Matter?
Authors: Jacobs Alan M.
Published: October 2008

How do ideas affect political decision making? Despite much evidence that ideas matter, relatively little is known about the specific mechanisms through which they influence actors' beliefs, goals, and preferences. Drawing on psychological findings, the article elaborates a cognitive mechanism through which ideational frameworks shape political elites' preferences among options. It argues that actors' mental models of the domains in which they are operating systematically guide their attention within processes of decision making. By leading them to reason about certain causal possibilities and data and to ignore and discount others, politicians' and policy makers' mental models can powerfully shape their causal belief sets and, in turn, their policy preferences. Furthermore, these attentional effects help explain why ideas persist under some conditions but change under others. The argument is empirically probed through an examination of key episodes in German pension politics over seven decades, drawing on detailed records of high-level policy deliberations.
From Patronage to Program
Authors: Hagopian Frances , Gervasoni Carlos , Moraes Juan Andres
Published: October 2008

This article explains the unanticipated emergence of party-oriented legislators and rising party discipline in Brazil since the early 1990s. The authors contend that deputies in Brazil became increasingly party oriented because the utilities of party-programmatic and patronage-based electoral strategies shifted with market reforms that created a programmatic cleavage in Brazilian politics and diminished the resource base for state patronage. The study introduces new measures of partisan campaigns, party polarization, and values that legislators attached to party programs and voter loyalty based on an original survey of the Brazilian Congress. Regression analysis confirms that deputies who believe that voters value party programs have run partisan, programmatic campaigns, and those in polarized parties and those who believe voters are loyal to the party are willing to delegate authority to party leaders and do not switch parties. Party polarization and the proximity of deputies' policy preferences to their party's mean explain discipline on 236 roll-call votes in the 51st legislature (1999-2001).
On the Duration of Political Power in Africa
Authors: Omgba Luc Désiré
Published: October 2008

It is often underlined that African oil-producing countries are politically unstable as a result of the role that this resource can play in political incentives. Based on data documenting the duration in office of heads of state of 26 African countries (North Africa and sub-Saharan Africa), this study reveals a surprising twist on the conventional wisdom: The purported instability of African oil-producing countries does not appear to extend to the executive branch of the state. Conversely, using survival analysis, this research suggests a positive link between oil rents and the duration in office of African leaders. Findings also reveal that other mineral rents do not exhibit the same stabilizing effect. The author's interpretation of these results is grounded in an analysis of the practicalities of oil investment and the strategic aspect of oil.
Reducing Fiber Readout of Structural Composite Panels
Authors: Wang C.S. , Iobst Stanley A.
Published: October 2008

A new molding process concept aimed at producing fabric-based structural composites with minimized out-of-mold surface fiber readout was proposed and validated in this study. The process first incorporates and lightly cures resins in fiber reinforcements to form fabric preforms. The partially cured preforms are subsequently over-molded with fresh resins to produce the finished panels. The concept was demonstrated using a vinyl ester resin reinforced with a large roving, plain weave glass fabric. By controlling the volumetric shrinkage of resin matrices through adding low profile additives and fillers, the proposed molding process successfully produced composite panels with significantly reduced surface fiber readout as indicated by surface profiles and corresponding Ra values measured by optical profilometry. The results also indicated that the surface texture of the fabric-based structural composites can eventually be made comparable to that of an ELPO-coated steel sheet.