bluuebunny/crossref_metadata_2025 huggingface dataset:
Intra-disk Parallelism
Authors: Sankar Sriram , Gurumurthi Sudhanva , Stan Mircea R.
Published: August 2008

Server storage systems use a large number of disks to achieve high performance, thereby consuming a significant amount of power. In this paper, we propose to significantly reduce the power consumed by such storage systems via intra-disk parallelism, wherein disk drives can exploit parallelism in the I/O request stream. Intra-disk parallelism can facilitate replacing a large disk array with a smaller one, using the minimum number of disk drives needed to satisfy the capacity requirements. We show that the design space of intra-disk parallelism is large and present a taxonomy to formulate specific implementations within this space. Using a set of commercial workloads, we perform a limit study to identify the key performance bottlenecks that arise when we replace a storage array that is tuned to provide high performance with a single high-capacity disk drive. We show that it is possible to match, and even surpass, the performance of a storage array for these workloads by using a single disk drive of sufficient capacity that exploits intra-disk parallelism, while significantly reducing the power consumed by the storage system. We evaluate the performance and power consumption of disk arrays composed of intra-disk parallel drives, and discuss engineering and cost issues related to the implementation and deployment of such disk drives.
Improving NAND Flash Based Disk Caches
Authors: Kgil Taeho , Roberts David , Mudge Trevor
Published: August 2008

Flash is a widely used storage device that provides high density and low power, appealing properties for general purpose computing. Today, its usual application is in portable special purpose devices such as MP3 players. In this paper we examine its use in the server domain—a more general purpose environment. Aggressive process scaling and the use of multi-level cells continues to improve density ahead of Moore’s Law predictions, making Flash even more attractive as a general purpose memory solution. Unfortunately, reliability limits the use of Flash. To seriously consider Flash in the server domain, architectural support must exist to address this concern. This paper first shows how Flash can be used in today’s server platforms as a disk cache. It then proposes two improvements. The first improves performance and reliability by splitting Flash based disk caches into separate read and write regions. The second improves reliability by employing a programmable Flash memory controller. It can change the error code strength (number of correctable bits) and the number of bits that a memory cell can store (cell density) according to the demands of the application. Our studies show that Flash reduces overall power consumed by the system memory and hard disk drive up to 3 times while maintaining performance. We also show that Flash lifetime can be improved by a factor of 20 when using a programmable Flash memory controller, if some performance degradation (below 5%) is acceptable.
VEAL
Authors: Clark Nathan , Hormati Amir , Mahlke Scott
Published: August 2008

Performance improvement solely through transistor scaling is becoming more and more difficult, thus it is increasingly common to see domain specific accelerators used in conjunction with general purpose processors to achieve future performance goals. There is a serious drawback to accelerators, though: binary compatibility. An application compiled to utilize an accelerator cannot run on a processor without that accelerator, and applications that do not utilize an accelerator will never use it. To overcome this problem, we propose decoupling the instruction set architecture from the underlying accelerators. Computation to be accelerated is expressed using a processor’s baseline instruction set, and light-weight dynamic translation maps the representation to whatever accelerators are available in the system. In this paper, we describe the changes to a compilation framework and processor system needed to support this abstraction for an important set of accelerator designs that support innermost loops. In this analysis, we investigate the dynamic overheads associated with abstraction as well as the static/dynamic tradeoffs to improve the dynamic mapping of loop-nests. As part of the exploration, we also provide a quantitative analysis of the hardware characteristics of effective loop accelerators. We conclude that using a hybrid static-dynamic compilation approach to map computation on to loop-level accelerators is an practical way to increase computation efficiency, without the overheads associated with instruction set modification.
From Speculation to Security
Authors: Chen Haibo , Wu Xi , Yuan Liwei , Zang Binyu , Yew Pen-chung , Chong Frederic T.
Published: August 2008

Dynamic information flow tracking (also known as taint tracking) is an appealing approach to combat various security attacks. However, the performance of applications can severely degrade without hardware support for tracking taints. This paper observes that information flow tracking can be efficiently emulated using deferred exception tracking in microprocessors supporting speculative execution. Based on this observation, we propose SHIFT, a low-overhead, software-based dynamic information flow tracking system to detect a wide range of attacks. The key idea is to treat tainted state (describing untrusted data) as speculative state (describing deferred exceptions). SHIFT leverages existing architectural support for speculative execution to track tainted state in registers and needs to instrument only load and store instructions to track tainted state in memory using a bitmap, which results in significant performance advantages. Moreover, by decoupling mechanisms for taint tracking from security policies, SHIFT can detect a wide range of exploits, including high-level semantic attacks. We have implemented SHIFT using the Itanium processor, which has support for deferred exceptions, and by modifying GCC to instrument loads and stores. A security assessment shows that SHIFT can detect both low-level memory corruption exploits as well as high-level semantic attacks with no false positives. Performance measurements show that SHIFT incurs about 1% overhead for server applications. The performance slowdown for SPEC-INT2000 is 2.81X and 2.27X for tracking at byte-level and wordlevel respectively. Minor architectural improvements to the Itanium processor (adding three simple instructions) can reduce the performance slowdown down to 2.32X and 1.8X for byte-level and word-level tracking, respectively.
Software-Controlled Priority Characterization of POWER5 Processor
Authors: Boneti Carlos , Cazorla Francisco J. , Gioiosa Roberto , Buyuktosunoglu Alper , Cher Chen-Yong , Valero Mateo
Published: August 2008

Due to the limitations of instruction-level parallelism, thread-level parallelism has become a popular way to improve processor performance. One example is the IBM POWER5TM processor, a two-context simultaneous-multithreaded dual-core chip. In each SMT core, the IBM POWER5 features two levels of thread resource balancing and prioritization. The first level provides automatic in-hardware resource balancing, while the second level is a software-controlled priority mechanism that presents eight levels of thread priorities. Currently, software-controlled prioritization is only used in limited number of cases in the software platforms due to lack of performance characterization of the effects of this mechanism. In this work, we characterize the effects of the software-based prioritization on several different workloads. We show that the impact of the prioritization significantly depends on the workloads coscheduled on a core. By prioritizing the right task, it is possible to obtain more than two times of throughput improvement for synthetic workloads compared to the baseline. We also present two application case studies targeting two different performance metrics: the first case study improves overall throughput by 23.7% and the second case study reduces the total execution time by 9.3%. In addition, we show the circumstances when a background thread can be run transparently without affecting the performance of the foreground thread.
Learning and Leveraging the Relationship between Architecture-Level Measurements and Individual User Satisfaction
Authors: Shye Alex , Ozisikyilmaz Berkin , Mallik Arindam , Memik Gokhan , Dinda Peter A. , Dick Robert P. , Choudhary Alok N.
Published: August 2008

The ultimate goal of computer design is to satisfy the end-user. In particular computing domains, such as interactive applications, there exists a variation in user expectations and user satisfaction relative to the performance of existing computer systems. In this work, we leverage this variation to develop more efficient architectures that are customized to end-users. We first investigate the relationship between microarchitectural parameters and user satisfaction. Specifically, we analyze the relationship between hardware performance counter (HPC) readings and individual satisfaction levels reported by users for representative applications. Our results show that the satisfaction of the user is strongly correlated to the performance of the underlying hardware. More importantly, the results show that user satisfaction is highly user-dependent. To take advantage of these observations, we develop a framework called Individualized Dynamic Voltage and Frequency Scaling (iDVFS). We study a group of users to characterize the relationship between the HPCs and individual user satisfaction levels. Based on this analysis, we use artificial neural networks to model the function from HPCs to user satisfaction for individual users. This model is then used online to predict user satisfaction and set the frequency level accordingly. A second set of user studies demonstrates that iDVFS reduces the CPU power consumption by over 25% in representative applications as compared to the Windows XP DVFS algorithm.
Achieving Out-of-Order Performance with Almost In-Order Complexity
Authors: Tseng Francis , Patt Yale N.
Published: August 2008

There is still much performance to be gained by out-of-order processors with wider issue widths. However, traditional methods of increasing issue width do not scale; that is, they drastically increase design complexity and power requirements. This paper introduces the braid, a compile-time identified entity that enables the execution core to scale to wider widths by exploiting the small fanout and short lifetime of values produced by the program. Braid processing requires identification by the compiler, minor extensions to the ISA, and support by the microarchitecture. The result from processing braids is performance within 9% of a very aggressive conventional out-of-order microarchitecture with almost the complexity of an in-order implementation.
A Two-Level Load/Store Queue Based on Execution Locality
Authors: Pericàs Miquel , Cristal Adrian , Cazorla Francisco J. , González Ruben , Veidenbaum Alex , Jiménez Daniel A. , Valero Mateo
Published: August 2008

Multicore processors have emerged as a powerful platform on which to efficiently exploit thread-level parallelism (TLP). However, due to Amdahl’s Law, such designs will be increasingly limited by the remaining sequential components of applications. To overcome this limitation it is necessary to design processors with many lower–performance cores for TLP and some high-performance cores designed to execute sequential algorithms. Such cores will need to address the memory-wall by implementing kilo-instruction windows. Large window processors require large Load/Store Queues that would be too slow if implemented using current CAMbased designs. This paper proposes an Epoch-based Load Store Queue (ELSQ), a new design based on Execution Locality. It is integrated into a large-window processor that has a fast, out-of-order core operating only on L1/L2 cache hits and N slower cores that process L2 misses and their dependent instructions. The large LSQ is coupled with the slow cores and is partitioned into N small and local LSQs, one per core. We evaluate ELSQ in a large-window environment, finding that it enables high performance at low power. By exploiting locality among loads and stores, ELSQ outperforms even an idealized central LSQ when implemented on top of a decoupled processor design.
Self-Optimizing Memory Controllers
Authors: Ipek Engin , Mutlu Onur , Martínez José F. , Caruana Rich
Published: August 2008

Efficiently utilizing off-chip DRAM bandwidth is a critical issuein designing cost-effective, high-performance chip multiprocessors(CMPs). Conventional memory controllers deliver relativelylow performance in part because they often employ fixed,rigid access scheduling policies designed for average-case applicationbehavior. As a result, they cannot learn and optimizethe long-term performance impact of their scheduling decisions,and cannot adapt their scheduling policies to dynamic workloadbehavior.We propose a new, self-optimizing memory controller designthat operates using the principles of reinforcement learning (RL)to overcome these limitations. Our RL-based memory controllerobserves the system state and estimates the long-term performanceimpact of each action it can take. In this way, the controllerlearns to optimize its scheduling policy on the fly to maximizelong-term performance. Our results show that an RL-basedmemory controller improves the performance of a set of parallelapplications run on a 4-core CMP by 19% on average (upto 33%), and it improves DRAM bandwidth utilization by 22%compared to a state-of-the-art controller.
Adaptive path scheduling for mobile element to prolong the lifetime of wireless sensor networks
Authors: Zhu Dakai , Tosun Ali Saman
Published: August 2008

Mobile elements, which can traverse the deployment area and convey the observed data from static sensor nodes to a base station, has been introduced for energy efficient data collection in wireless sensor networks (WSNs). However, most existing solutions only calculate a single path for the mobile element, which may lead to quick energy depletion for sensor nodes that are far away from the path. In this paper, for real-time data collection in a WSN with one mobile element, we study the adaptive path scheduling problem for prolonging the lifetime of the WSN. Here, multiple paths are planned and the mobile element follows the paths in turn to balance the energy consumption on individual sensor nodes, thus to extend the WSN's lifetime. We first illustrate the problem with one motivational example. Then, for cases where the movement of the mobile element is restricted (e.g., straight lines), we propose and analyze the optimal solutions. For the general cases, we discuss the issues involved and speculate our future research directions.
Maximizing job benefits on multiprocessor systems using a greedy algorithm
Authors: Sanati Behnaz , Cheng Albert Mo Kim
Published: August 2008

This project considers a benefit model for on-line preemptive multiprocessor scheduling. In this model, each job arrives with its own benefit function and execution time. The flow time of a job is the time between its arrival and its completion. The benefit function determines the benefit gained for any given flow time. The goal is to maximize the total benefit gained only by the jobs that meet their deadlines. In order to achieve this goal, a variety of approximation algorithms and their applications in multiprocessor scheduling were studied. A greedy algorithm with 2- approximation ratio is proposed to be added to an existing benefit based scheduling algorithm, in order to reduce the delay of each job, by assigning it to the processor with least utilization so far. This method will decrease the flow time of the jobs, resulting in higher benefits gained by each job. Also, evaluation of this approach shows that it uses the CPU cycles more efficiently by providing more balanced distribution of the jobs between the processors. Therefore, more jobs can meet their deadlines and add their gained benefits to the total benefit. In addition, the proposed method is computationally less expensive than the existing benefit based method.
A testbed for secure and robust SCADA systems
Authors: Giani Annarita , Karsai Gabor , Roosta Tanya , Shah Aakash , Sinopoli Bruno , Wiley Jon
Published: August 2008

The Supervisory Control and Data Acquisition System (SCADA) monitor and control real-time systems. SCADA systems are the backbone of the critical infrastructure, and any compromise in their security can have grave consequences. Therefore, there is a need to have a SCADA testbed for checking vulnerabilities and validating security solutions. In this paper we develop such a SCADA testbed.
Online auctions and generalized secretary problems
Authors: Babaioff Moshe , Immorlica Nicole , Kempe David , Kleinberg Robert
Published: August 2008

We present generalized secretary problems as a framework for online auctions. Elements, such as potential employees or customers, arrive one by one online. After observing the value derived from an element, but without knowing the values of future elements, the algorithm has to make an irrevocable decision whether to retain the element as part of a solution, or reject it. The way in which the secretary framework differs from traditional online algorithms is that the elements arrive in uniformly random order.

Many natural online auction scenarios can be cast as generalized secretary problems, by imposing natural restrictions on the feasible sets. For many such settings, we present surprisingly strong constant factor guarantees on the expected value of solutions obtained by online algorithms. The framework is also easily augmented to take into account time-discounted revenue and incentive compatibility. We give an overview of recent results and future research directions.
Ms Pac-Man competition
Authors: Lucas Simon M.
Published: August 2008

IEEE WCCI 2008 in Hong Kong played host to the latest Ms Pac-Man competition, organised by Simon Lucas as an activity of the IEEE CIS Games Technical Committee. The competition attracted 11 entries from teams all around the world, with the winning entry by Alan Fitzgerald, Peter Kemeraitis, and Clare Bates Congdon from the University of Southern Maine (USM) achieving a high-score of 15,970.
A lightweight streaming layer for multicore execution
Authors: Zhang David , Li Qiuyuan J. , Rabbah Rodric , Amarasinghe Saman
Published: August 2008

As multicore architectures gain widespread use, it becomes increasingly important to be able to harness their additional processing power to achieve higher performance. However, exploiting parallel cores to improve single-program performance is difficult from a programmer's perspective because most existing programming languages dictate a sequential method of execution.

Stream programming, which organizes programs by independent filters communicating over explicit data channels, exposes useful types of parallelism that can be exploited. However, there is still the burden of mapping high-level stream programs to specific multicore architectures. The complexities of each architecture's underlying details makes it difficult to schedule the execution of a stream program with high performance.

In this paper, we present the specifications for an intermediate layer between the stream program and the target architecture. This multicore streaming layer (MSL) provides a common level of abstraction that facilitates efficient execution of stream programs by making it easier for compilers to manage computation, and by providing automatic orchestration and optimization of communication when appropriate. We implemented a framework for one such instance of the MSL targeted to the Cell processor and the StreamIt language and achieved greater than 88% utilization on all benchmarks with relatively small amounts of code. The framework can also be applied to other architectures and stream programming languages to enhance generality and portability.
Towards modeling & analysis of consolidated CMP servers
Authors: Apparao Padma , Iyer Ravi , Newell Don
Published: August 2008

As virtualization becomes ubiquitous in data centers, it becomes imperative that the definition of future multi-core platform architectures take into account the performance behavior and requirements of consolidated servers. However, performance analysis of commercial servers has traditionally been focused on individual parallel benchmarks running in dedicated mode. In this paper, we present an approach to developing a performance model for virtualized CMP servers potentially running heterogeneous workloads simultaneously. We show that a consolidation performance model can be developed by decomposing the problem into three constituent parts: (a) core interference due to consolidation, (b) cache interference due to consolidation and (c) virtualization overheads. Having laid out the consolidation framework, we then perform an initial case study with a new consolidation benchmark (vConsolidate). We present vConsolidate measurement characteristics on a Core 2 Duo-based server platform and then apply the performance model in order to predict the performance slowdown of each workload due to consolidation. We show that the model constructed is capable of achieving sufficient accuracy and discuss how to improve the accuracy in the future. Last but not least, we describe the extensions required to develop a complete generalized consolidation performance model.
Molecular genetic and biochemical analyses of FGF23 mutations in familial tumoral calcinosis
Authors: Garringer Holly J. , Malekpour Mahdi , Esteghamat Fatemehsadat , Mortazavi Seyed M. J. , Davis Siobhan I. , Farrow Emily G. , Yu Xijie , Arking Dan E. , Dietz Harry C. , White Kenneth E.
Published: August 2008

Fibroblast growth factor 23 (FGF23) is a hormone required for normal renal phosphate reabsorption. FGF23 gain-of-function mutations result in autosomal dominant hypophosphatemic rickets (ADHR), and FGF23 loss-of-function mutations cause familial hyperphosphatemic tumoral calcinosis (TC). In this study, we identified a novel recessive FGF23 TC mutation, a lysine (K) substitution for glutamine (Q) (160 C > A) at residue 54 (Q54K). To understand the molecular consequences of all known FGF23-TC mutants (H41Q, S71G, M96T, S129F, and Q54K), these proteins were stably expressed in vitro. Western analyses revealed minimal amounts of secreted intact protein for all mutants, and ELISA analyses demonstrated high levels of secreted COOH-terminal FGF23 fragments but low amounts of intact protein, consistent with TC patients' FGF23 serum profiles. Mutant protein function was tested and showed residual, yet decreased, bioactivity compared with wild-type protein. In examining the role of the FGF23 COOH-terminal tail (residues 180–251) in protein processing and activity, truncated mutants revealed that the majority of the residues downstream from the known FGF23 SPC protease site (176RXXR179/S180) were not required for protein secretion. However, residues adjacent to the RXXR site (between residues 188 and 202) were required for full bioactivity. In summary, we report a novel TC mutation and demonstrate a common defect of reduced FGF23 stability for all known FGF23-TC mutants. Finally, the majority of the COOH-terminal tail of FGF23 is not required for protein secretion but is required for full bioactivity.
Structural Condition Monitoring by Cumulative Harmonic Analysis of Random Vibration
Authors: Takahashi Yoshinori , Taniguchi Toru , Tohyama Mikio
Published: August 2008

Analysis of signals based on spectral accumulation has great potential for enabling the condition
of structures excited by natural forces to be monitored using random vibration records. This
article describes cumulative harmonic analysis (CHA) that was achieved by introducing a spectral
accumulation function into Berman and Fincham′s conventional cumulative analysis, thus enabling
potential new areas in cumulative analysis to be explored. CHA effectively enables system
damping and modal overlap conditions to be visualized without the need for transient‐vibration
records. The damping and modal overlap conditions lead to a spectral distribution around dominant
spectral peaks due to structural resonance. This distribution can be revealed and emphasized
by CHA records of magnitude observed even within short intervals in stationary random vibration
samples.
Wetting of Al2O3 by Molten Aluminum: The Influence of BaSO4 Additions
Authors: Aguilar-Santillan Joaquin
Published: August 2008

The effects of BaSO4 additions on the wetting of alumina by molten aluminum were studied by the sessile drop technique. To study the effect of BaSO4 decomposition (1100–1150∘C), the additions were treated at two temperatures 700∘C (973 K) and 1450∘C (1723 K), respectively. BaSO4 additions at low and high temperatures did not improve the nonwetting character of these compositions. However, at higher firing temperature, the formation of BA6 (BaO•6Al2O3) has a nonwetting trend with increasing its content. To address the BA6 specifically a pure BaO•6Al2O3 was produced and tested. It was more nonwetting than the pure alumina. After the analysis of the contact angles for the BaSO4 and the BA6 (BaO•6Al2O3), it was concluded that these additions to alumina do not inhibit wetting by molten aluminum. In fact, at the addition levels common for refractories, the wetting tendency of molten aluminum is enhanced. Alternative explanations for the effectiveness of BaSO4 additions to alumina refractories are discussed.
Efficient Execution of Service Composition for Content Adaptation in Pervasive Computing
Authors: Fawaz Yaser , Berhe Girma , Brunie Lionel , Scuturici Vasile-Marian , Coquil David
Published: August 2008

Multimedia content adaptation has been proved to be an effective mechanism to mitigate the problem of devices and networks heterogeneity and constraints in pervasive computing environments. Moreover, it enables to deliver data taking into consideration the user's preferences and the context of his/her environment. In this paper, we present an algorithm for service composition and protocols for executing service composition plan. Both the algorithm and the protocols are implemented in our distributed content adaptation framework (DCAF) which provides a service-based content adaptation architecture. Finally, a performance evaluation of the algorithm and the protocols is presented.
A Simple Nonlinear Dynamic Model for Unemployment: Explaining the Spanish Case
Authors: Faria João Ricardo , León-Ledesma Miguel A.
Published: August 2008

Spanish unemployment is characterized by three distinct regimes of low, medium, and high unemployment and by a fast transition between them. This paper presents a simple nonlinear dynamic model that is able to explain this behavior with multiple equilibria and jumps describing the transition between equilibria. The model has only a small number of parameters capturing the fundamentals of labor markets and macroeconomic and institutional factors. The model is capable of generating unemployment dynamics that encompass the “unique” natural rate hypothesis, the structuralist hypothesis, and the hysteresis hypothesis.
Electroanatomic Mapping of the Left Ventricle in a Porcine Model of Chronic Myocardial Infarction With Magnetic Resonance–Based Catheter Tracking
Authors: Dukkipati Srinivas R. , Mallozzi Richard , Schmidt Ehud J. , Holmvang Godtfred , d'Avila Andre , Guhde Renee , Darrow Robert D. , Slavin Glenn , Fung Maggie , Malchano Zachary , Kampa Greg , Dando Jeremy D. , McPherson Christina , Foo Thomas K. , Ruskin Jeremy N. , Dumoulin Charles L. , Reddy Vivek Y.
Published: August 2008

Background—

X-ray fluoroscopy constitutes the fundamental imaging modality for catheter visualization during interventional electrophysiology procedures. The minimal tissue discriminative capability of fluoroscopy is mitigated in part by the use of electroanatomic mapping systems and enhanced by the integration of preacquired 3-dimensional imaging of the heart with computed tomographic or magnetic resonance (MR) imaging. A more ideal paradigm might be to use intraprocedural MR imaging to directly image and guide catheter mapping procedures.

Methods and Results—

An MR imaging–based electroanatomic mapping system was designed to assess the feasibility of navigating catheters to the left ventricle in vivo using MR tracking of microcoils incorporated into the catheters, measuring intracardiac ventricular electrograms, and integrating this information with 3-dimensional MR angiography and myocardial delayed enhancement images to allow ventricular substrate mapping. In all animals (4 normal, and 10 chronically infarcted swine), after transseptal puncture under fluoroscopic guidance, catheters were successfully navigated to the left ventricle with MR tracking (13 to 15 frames per second) by both transseptal and retrograde aortic approaches. Electrogram artifacts related to the MR imaging gradient pulses were successfully removed with analog and digital signal processing. In all animals, it was possible to map the entire left ventricle and to project electrogram voltage amplitude maps to identify the scarred myocardium.

Conclusions—

It is possible to use MR tracking to navigate catheters to the left ventricle, to measure electrogram activity, and to render accurate 3-dimensional voltage maps in a porcine model of chronic myocardial infarction, completely in the MR imaging environment. Myocardial delayed enhancement guidance provided dense sampling of the proximity of the infarct and accurate localization of complex infarcts.
Cardiac Magnetic Resonance With T2-Weighted Imaging Improves Detection of Patients With Acute Coronary Syndrome in the Emergency Department
Authors: Cury Ricardo C. , Shash Khalid , Nagurney John T. , Rosito Guido , Shapiro Michael D. , Nomura Cesar H. , Abbara Suhny , Bamberg Fabian , Ferencik Maros , Schmidt Ehud J. , Brown David F. , Hoffmann Udo , Brady Thomas J.
Published: August 2008

Background—

Cardiac magnetic resonance (CMR) imaging permits early triage of patients presenting to the emergency department with acute chest pain but has been limited by the inability to differentiate new from old myocardial infarction. Our objective was to evaluate a CMR protocol that includes T2-weighted imaging and assessment of left ventricular wall thickness in detecting patients with acute coronary syndrome in the emergency department.

Methods and Results—

In this prospective cohort observational study, we enrolled patients presenting to the emergency department with acute chest pain, negative cardiac biomarkers, and no ECG changes indicative of acute ischemia. The CMR protocol consisted of T2-weighted imaging, first-pass perfusion, cine function, delayed-enhancement magnetic resonance imaging, and assessment of left ventricular wall thickness. The clinical outcome (acute coronary syndrome) was defined by review of clinical charts by a consensus panel that used American Heart Association/American College of Cardiology guidelines. Among 62 patients, 13 developed acute coronary syndrome during the index hospitalization. The mean CMR time was 32±8 minutes. The new CMR protocol (with the addition of T2-weighted and left ventricular wall thickness) increased the specificity, positive predictive value, and overall accuracy from 84% to 96%, 55% to 85%, and 84% to 93%, respectively, compared with the conventional CMR protocol (cine, perfusion, and delayed-enhancement magnetic resonance imaging). Moreover, in a logistic regression analysis that contained information on clinical risk assessment (c-statistic=0.695) and traditional cardiac risk factors (c-statistic=0.771), the new CMR protocol significantly improved the c-statistic to 0.958 (
P
<0.0001).

Conclusions—

The present study indicates that a new CMR protocol improves the detection of patients with acute coronary syndrome in the emergency department and adds significant value over clinical assessment and traditional cardiac risk factors.
Contemporary Analysis of Descending Thoracic and Thoracoabdominal Aneurysm Repair
Authors: Greenberg Roy K. , Lu Qingsheng , Roselli Eric E. , Svensson Lars G. , Moon Michael C. , Hernandez Adrian V. , Dowdall Joseph , Cury Marcelo , Francis Catherine , Pfaff Kathryn , Clair Daniel G. , Ouriel Kenneth , Lytle Bruce W.
Published: August 2008

Background—

Endovascular repair of thoracic aneurysm has demonstrated low risks of mortality and spinal cord ischemia (SCI), but few large series have been published on endovascular thoracoabdominal aneurysm repair, and reports suffer from a lack of accurate comparison with similar open surgical procedures.

Methods and Results—

A consecutive cohort of patients with thoracic and thoracoabdominal aneurysms treated electively with endovascular repair (ER) or surgical repair (SR) techniques between 2001 and 2006 were analyzed. The association between repair technique and SCI was evaluated with univariable analysis. Adjustments for potential confounders and for the propensity to receive ER or SR were also performed in multivariable analysis. A total of 724 patients (352 ER, 372 SR) underwent repair. The mean age was 67 years, and 65% were male. ER patients were on average 9 years older (
P
<0.001), had more comorbid conditions, and more frequently had prior distal repair (
P
<0.001) or underwent a type I or IV repair. SR patients more commonly had chronic dissection or required type II or type III repairs (
P
<0.001). Mortality at 30 days (5.7% ER versus 8.3% SR,
P
=0.2) and 12 months (15.6% ER versus 15.9% SR,
P
=0.9) was similar. A borderline difference in SCI was found between repair techniques: 4.3% of ER and 7.5% of SR patients (
P
=0.08) had SCI. In patients with ER, prior distal aortic operation was associated with the development of SCI in univariable analysis (odds ratio 4.1, 95% confidence interval 1.4 to 11.7). Multivariable analysis showed that the type of required repair (type I, II, III, or IV) was the primary factor associated with the development of SCI in ER and SR patients.

Conclusion—

No significant difference in the incidence of mortality or SCI was found between ER and SR techniques. The strongest factor associated with SCI remains the extent of the disease. Further studies are indicated to compare ER with patients considered eligible for SR.
Southern Hemisphere Winter Extratropical Cyclone Characteristics and Vertical Organization Observed with the ERA-40 Data in 1979–2001
Authors: Lim Eun-Pa , Simmonds Ian
Published: August 2008

The mean characteristics and trends of Southern Hemisphere (SH) winter extratropical cyclones occurring at six levels of the troposphere over the period 1979–2001 have been investigated using the 40-yr ECMWF Re-Analysis (ERA-40) data. Cyclonic systems were identified with the Melbourne University cyclone finding and tracking scheme.

This study shows that mean sea level pressure (MSLP) cyclones are more numerous, more intense, smaller, deeper, and slower moving than higher-level cyclones. The novel vertical tracing scheme devised for this research revealed that about 52% of SH winter MSLP cyclones have a vertically well organized structure, extending through to the 500-hPa level. About 80% of these vertically coherent SH cyclones keep their westward tilt until the surface cyclones reach their maximum depths, and the mean distance is 300 km between the surface and the 500-hPa level cyclone centers when the surface cyclones obtain their maturity. According to the authors’ definition of vertical organization, explosively developing cyclones are vertically very well organized systems, whose surface development is antecedent to their 500-hPa level counterpart.

Over 1979–2001 cyclones have increased in their system density, intensity, and translational velocity but decreased in their scale at almost all levels. However, some of the trends are not statistically significant. The proportion of vertically well organized systems in the entire population of SH winter extratropical cyclones has considerably increased over the last 23 yr, and the mean distance between the surface and the 500-hPa- level cyclone centers has decreased. Such changes in vertical organization of extratropical cyclones are statistically significant at the 95% confidence level.
Social Support and Feelings of Hostility Among Released Inmates
Authors: Hochstetler Andy , DeLisi Matt , Pratt Travis C.
Published: August 2008

There is broad consensus that the strains of imprisonment and unsupported release affect offenders’ mental health and operate to the detriment of their chances of successful reintegration. Drawing on data from 208 male inmates, the authors examine the mediating and moderating influences of social support on the links between inmates’ perceptions of prison conditions and other background variables on parolees’ feelings of hostility—a factor theoretically linked to reoffending—upon release. The results demonstrate that social support partially or completely mediates background characteristics and conditions the influence of prison perceptions on released inmates’ levels of hostility.
Gender Differences in Factors Contributing to Institutional Misconduct
Authors: Gover Angela R. , Pérez Deanna M. , Jennings Wesley G.
Published: August 2008

Importation and deprivation theories are typically offered to explain the process by which inmates adjust to prison environments. Nearly all prior empirical tests of these theories have exclusively relied on samples of male inmates. Using self-report and official data from 247 male and female inmates confined to correctional institutions in a southeastern state, this study makes an important contribution to the correctional literature by examining whether theoretical predictors of infraction behavior are similar for males and females. Consistent with prior research, findings from zero-inflated Poisson regression models indicate that measures of both importation and deprivation theories significantly influence misconduct behavior. Findings, however, indicate that predictors of institutional misconduct are different for males and females. These findings support the development of gender-specific correctional programming that considers distinct needs of men versus women, with specific emphasis on programs that respond to the unique circumstances of female offenders.
The Effect of CCTV on Prisoner Misbehavior
Authors: Allard Troy J. , Wortley Richard K. , Stewart Anna L.
Published: August 2008

Despite the widespread use of closed-circuit television (CCTV) in prison, few studies have explored its effect on prisoner misbehavior. Research was conducted to explore two research questions: (a) Does CCTV have a greater preventative effect on nonviolent than on violent prisoner misbehavior? and (b) Does CCTV have a greater preventative effect on planned than on unplanned violent behavior? Data were obtained on the 1,116 incidents involving aberrant prisoner behavior that occurred at four prisons in Queensland, Australia, during a 6-year period. Findings indicate that violent and unplanned misbehavior was relatively more likely to occur in view of CCTV coverage than was nonviolent and planned misbehavior. The implications for the prevention of aberrant inmate behavior and for researchers' understanding of the impact of CCTV on violence are discussed.
Framing Policy Debates
Authors: Lee Nam-Jin , McLeod Douglas M. , Shah Dhavan V.
Published: August 2008

This study examines how the news frames that journalists use to present contentious policy debates shape reasoning processes and opinion outcomes. Drawing on the notion that framing is a cognitive process in which the message affects how individuals weigh existing considerations (i.e., political orientations and relevant attitudes/beliefs) to make a judgment, the authors conducted two experiments in which they presented participants with news stories in which policy conflicts were described as either a clash of underlying values and principles (i.e., a value frame) or as a clash of political interests and strategies (i.e., a strategy frame). The results suggest that the framed news stories failed to change issue opinions directly but did alter the importance of the considerations used to make judgments on relevant issues. Specifically, individuals tend to react to strategy frames by discounting partisan affiliation as a primary consideration, turning to other salient alternatives when making judgments.
The Geographies of Secondary City Growth in a Globalized China
Authors: Airriess Christopher
Published: August 2008

China's dramatic economic growth trajectory during the post-1978 reform era has been in part dependent on the important role of secondary cities as regional articulation points in the country's engagement with globalization. This article compares the urban—economic experiences of the two prefecture-level municipalities of Dongguan and Suzhou with respect to a number of overlapping vantage points, each possessing an inherent spatiality. These include a national administrative rescaling of urban places producing greater economic autonomy at local and regional scales, the differing temporal engagement of each region with the global economy, and the structure of regional production chains, particularly in relation to the global gateway cities of the larger urban regions in which each secondary city is locationally and functionally embedded.
Grandparents Caring for their Grandchildren
Authors: Hank Karsten , Buber Isabella
Published: August 2008

Introducing findings from the 2004 Survey of Health, Ageing, and Retirement in Europe (SHARE), this research complements the large number of recent U.S. studies on the role of grandparents in caring for their grandchildren. For 10 continental European countries, the authors investigate cross-national variations in grandparent-provided child care as well as differences in characteristics of the providers and recipients of care. Although they find strong involvement of grandparents in their grandchildren's care across all countries, they also identify significant variations in the prevalence and intensity of care along the geographic lines of different child care and (maternal or female) employment regimes in Europe. Rooted in long-standing family cultures, the observed patterns suggest a complex interaction between welfare state—provided services and intergenerational family support in shaping the work—family nexus for younger parents. The authors conclude with a brief discussion of possible consequences of grandmothers' increasing labor force participation for child care arrangements.
Nutrition Screening vs Nutrition Assessment: How Do They Differ?
Authors: Charney Pamela
Published: August 2008

Interest in nutrition screening has increased rapidly due to regulatory requirements as well as the known adverse impact of nutrition deficits on outcomes of hospitalization. Screening programs now in use in acute care are often complex and difficult to administer. Current interest in evaluation of all aspects of healthcare using evidence‐based methods requires that nutrition screening programs be thoroughly evaluated. Clinicians attempting to evaluate evidence in support of different methods to identify patients who might have nutrition problems are often confronted with research that blurs the distinction between screening and assessment. Therefore, before identifying methods to conduct nutrition screening, it is necessary to have a thorough understanding of the difference between screening and assessment. A review of terms, definitions, and programs for screening in other areas of healthcare will provide some guidance to the clinician faced with development, implementation, and monitoring of nutrition screening programs. This facilitates development of nutrition assessment programs so that patients who have a nutrition screen are assessed in a timely fashion and receive appropriate nutrition interventions.
Comment on:  Safety and Efficacy of a Fish‐Oil‐Based Fat Emulsion in the Treatment of Parenteral Nutrition‐Associated Liver Disease
Authors: Biank Vincent F.
Published: August 2008

Background: Parenteral nutrition‐associated liver disease can be a progressive and fatal entity in children with short‐bowel syndrome. Soybean‐fat emulsions provided as part of standard parenteral nutrition may contribute to its pathophysiology. Methods: The authors compared safety and efficacy outcomes of a fish‐oil‐based fat emulsion in 18 infants with short‐bowel syndrome who developed cholestasis (serum direct bilirubin level of >2 mg/dL) while receiving soybean emulsions with those from a historical cohort of 21 infants with short‐bowel syndrome who also developed cholestasis while receiving soybean emulsions. The primary end point was time to reversal of cholestasis (3 consecutive measurements of serum direct bilirubin level of >2 mg/dL). Results: Among survivors, the median time to reversal of cholestasis was 9.4 and 44.1 weeks in the fish‐oil and historical cohorts, respectively. Subjects who received fish‐oil‐based emulsion experienced reversal of cholestasis 4.8 times faster than those who received soybean emulsions and 6.8 times faster in analysis adjusted for baseline bilirubin concentration, gestational age, and the diagnosis of necrotizing enterocolitis. A total of 2 deaths and 0 liver transplantations were recorded in the fish‐oil cohort and 7 deaths and 2 transplantations in the historical cohort. The provision of fish‐oil‐based fat emulsion was not associated with essential fatty acid deficiency, hypertriglyceridemia, coagulopathy, infections, or growth delay. Conclusions: Parenteral fish‐oil‐based fat emulsions are safe and may be effective in the treatment of parenteral nutrition‐associated liver disease.
Waist Circumference Measurement in Clinical Practice
Authors: Ness‐Abramof Rosane , Apovian Caroline M.
Published: August 2008

The obesity epidemic is a major public health problem worldwide. Adult obesity is associated with increased morbidity and mortality. Measurement of abdominal obesity is strongly associated with increased cardiometabolic risk, cardiovascular events, and mortality. Although waist circumference is a crude measurement, it correlates with obesity and visceral fat amount, and is a surrogate marker for insulin resistance. A normal waist circumference differs for specific ethnic groups due to different cardiometabolic risk. For example, Asians have increased cardiometabolic risk at lower body mass indexes and with lower waist circumferences than other populations. One criterion for the diagnosis of the metabolic syndrome, according to different study groups, includes measurement of abdominal obesity (waist circumference or waist‐to‐hip ratio) because visceral adipose tissue is a key component of the syndrome. The waist circumference measurement is a simple tool that should be widely implemented in clinical practice to improve cardiometabolic risk stratification.
Social Support and Symptom Distress in Adolescents/Young Adults With Cancer
Authors: Corey Amy L. , Haase Joan E. , Azzouz Faouzi , Monahan Patrick O.
Published: August 2008

The purpose of this secondary analysis was to describe the relationships of friend, family, and health care provider social support to pain, fatigue, depressed mood, and insomnia in adolescents and young adults with cancer using the Adolescent Resilience Model. Specific aims of the study were to describe the relationships of 3 separate sources of perceived support—friends, family, and health care providers to the symptom-related distress of pain, fatigue, depressed mood, and insomnia.