bluuebunny/crossref_metadata_2025 huggingface dataset:
A Pseudo-Rigid-Body Model of the Human Spine to Predict Implant-Induced Changes on Motion
Authors: Halverson Peter A. , Bowden Anton E. , Howell Larry L.
Published: October 2011

Injury, instrumentation, or surgery may change the functional biomechanics of the spine. Adverse changes at one level may affect the adjacent levels. Modeling these changes can increase the understanding of adjacent-level effects and may help in the creation of devices that minimize adverse outcomes. The current modeling techniques (e.g., animal models, in vitro testing, and finite element analysis) used to analyze these effects are costly and are not readily accessible to the clinician. It is proposed that the pseudo-rigid-body model(PRBM) may be used to accurately predict adjacent level effects in a quick and cost effective manner that may lend itself to a clinically relevant tool for identifying the adjacent-level effects of various treatment options for patients with complex surgical indications. A PRBM of the lumbar spine (lower back) was developed using a compliant mechanism analysis approach. The global moment-rotation response, relative motion, and local moment-rotation response of a cadaveric specimen were determined through experimental testing under three conditions: intact, fused, and implanted with a prototype total disc replacement. The spine was modeled using the PRBM and compared with the values obtained through in-vitro testing for the three cases. The PRBM accurately predicted the moment-rotation response of the entire specimen. Additionally, the PRBM predicted changes in relative motion patterns of the specimen. The resulting models show particular promise in evaluating various procedures and implants in a clinical setting and in the early stage design process.
Reduction in Fluoroquinolone Use following Introduction of Ertapenem into a Hospital Formulary Is Associated with Improvement in Susceptibility of Pseudomonas aeruginosa to Group 2 Carbapenems: a 10-Year Study
Authors: Cook Paul P. , Gooch Michael , Rizzo Shemra
Published: October 2011

We examined the effect of the addition of ertapenem to our hospital formulary on the resistance of nosocomial
Pseudomonas aeruginosa
to group 2 carbapenems (imipenem, meropenem, and doripenem). This was a retrospective, observational study conducted between 1 January 2000 and 31 January 2009 at a large, tertiary-care hospital. Autoregressive integrated moving average (ARIMA) regression models were used to evaluate the effect of ertapenem use on the susceptibility of
Pseudomonas aeruginosa
to group 2 carbapenems as well as on the use of the group 2 carbapenems, ciprofloxacin, and other antipseudomonal drugs (i.e., tobramycin, cefepime, and piperacillin-tazobactam). Resistance was expressed as a percentage of total isolates as well as the number of carbapenem-resistant bacterial isolates per 10,000 patient days. Pearson correlation was used to assess the relationship between antibiotic use and carbapenem resistance. Following the addition of ertapenem to the formulary, there was a statistically significant decrease in the percentage of
Pseudomonas aeruginosa
isolates resistant to the group 2 carbapenems (
P
= 0.003). Group 2 carbapenem use and the number of carbapenem-resistant
Pseudomonas aeruginosa
isolates per 10,000 patient days did not change significantly over the time period. There was a large decrease in the use of ciprofloxacin (
P
= 0.0033), and there was a correlation of ciprofloxacin use with the percentage of isolates resistant to the group 2 carbapenems (ρ = 0.47,
P
= 0.002). We suspect that the improvement in susceptibility of
Pseudomonas aeruginosa
to group 2 carbapenems was related to a decrease in ciprofloxacin use.
Pharmacokinetics of Isoniazid, Rifampin, and Pyrazinamide in Children Younger than Two Years of Age with Tuberculosis: Evidence for Implementation of Revised World Health Organization Recommendations
Authors: Thee S. , Seddon J. A. , Donald P. R. , Seifart H. I. , Werely C. J. , Hesseling A. C. , Rosenkranz B. , Roll S. , Magdorf K. , Schaaf H. S.
Published: October 2011

The World Health Organization (WHO) recently issued revised first-line antituberculosis (anti-TB) drug dosage recommendations for children. No pharmacokinetic studies for these revised dosages are available for children <2 years. The aim of the study was to document the pharmacokinetics of the first-line anti-TB agents in children <2 years of age comparing previous and revised WHO dosages of isoniazid (INH; 5 versus 10 mg/kg/day), rifampin (RMP; 10 versus 15 mg/kg/day), and pyrazinamide (PZA; 25 versus 35 mg/kg/day) and to investigate the effects of clinical covariates, including HIV coinfection, nutritional status, age, gender, and type of tuberculosis (TB), and the effect of NAT2 acetylator status. Serum INH, PZA, and RMP levels were prospectively assessed in 20 children <2 years of age treated for TB following the previous and the revised WHO dosage recommendations. Samples were taken prior to dosing and at 0.5, 1.5, 3, and 5 h following dosing. The maximum drug concentration in serum (
C
max
), the time to
C
max
(
t
max
), and the area under the concentration-time curve (AUC) were calculated. Eleven children had pulmonary and 9 had extrapulmonary TB. Five were HIV infected. The mean
C
max
(μg/ml) following the administration of previous/revised dosages were as follows: INH, 3.19/8.11; RMP, 6.36/11.69; PZA, 29.94/47.11. The mean AUC (μg·h/ml) were as follows: INH, 8.09/20.36; RMP, 17.78/36.95; PZA, 118.0/175.2. The mean
C
max
and AUC differed significantly between doses. There was no difference in the
t
max
values achieved. Children less than 2 years of age achieve target concentrations of first-line anti-TB agents using revised WHO dosage recommendations. Our data provided supportive evidence for the implementation of the revised WHO guidelines for first-line anti-TB therapy in young children.
Regional and temporal variations in organ donation across the UK (secondary analyses of databases)
Authors: McGlade Donal , Rae Gordon , McClenahan Carol , Pierscionek Barbara
Published: October 2011

Objectives

To explore regional variations in donation of cadaveric solid organs and tissues across the four devolved health administrations of the UK (England, Scotland, Wales and Northern Ireland).

Design

A secondary analysis of databases from NHS Blood & Transplant (1990–2009) and from the National Organ Procurement Service for the Republic of Ireland, Eurotransplant International Foundation and Scandiatransplant.

Results

After adjusting for time, statistically significant differences were found among the four regions (p<0.001) for liver donations. The only exceptions were between England and Scotland and between Wales and Northern Ireland where the differences were not significant following a Bonferroni correction (p>0.008). England had significantly fewer heart donations than both Wales (p<0.001) and Northern Ireland (p=0.005). There were no significant differences among the four regions for lung donations. Regional variations in kidney and corneal donations were moderated by time. Northern Ireland, however, has had consistently lower corneal donation rates than the other three regions.

Conclusion

Organ donation rates over the last two decades vary in the four UK regions, and this variation depends on the type of organ donated. Further exploration of underlying factors, organisational issues, practices and attitudes to organ donation in the four regions of the UK, taking into account findings from EU countries with varying approaches to presumed consent, needs to be undertaken before such legislation is introduced across the UK.
Penile amputation and scrotal urethrostomy in 18 dogs
Authors: Burrow R. D. , Gregory S. P. , Giejda A. A. , White R. N.
Published: October 2011

The objective of this study was to report the signalment, indications for surgery, postoperative complications and outcome in dogs undergoing penile amputation and scrotal urethrostomy. Medical records of three surgical referral facilities were reviewed for dogs undergoing penile amputation and scrotal urethrostomy between January 2003 and July 2010. Data collected included signalment, presenting signs, indication for penile amputation, surgical technique, postoperative complications and long‐term outcome. Eighteen dogs were included in the study. Indications for surgery were treatment of neoplasia (n=6), external or unknown penile trauma (n=4), penile trauma or necrosis associated with urethral obstruction with calculi (n=3), priapism (n=4) and balanoposthitis (n=1). All dogs suffered mild postoperative haemorrhage (posturination and/or spontaneous) from the urethrostomy stoma for up to 21 days (mean 5.5 days). Four dogs had minor complications recorded at suture removal (minor dehiscence (n=1), mild bruising and swelling around the urethrostomy site and mild haemorrhage at suture removal (n=2), and granulation at the edge of stoma (n=1)). One dog had a major complication (wound dehiscence and subsequent stricture of the stoma). Long‐term outcome was excellent in all dogs with non‐neoplastic disease. Local tumour recurrence and/or metastatic disease occurred within five to 12 months of surgery in two dogs undergoing penile amputation for the treatment of neoplasia. Both dogs were euthanased.
CTCF function is modulated by neighboring DNA binding factors
Authors: Weth Oliver , Renkawitz Rainer
Published: October 2011

The zinc-finger protein CTCF was originally identified in the context of gene silencing and gene repression (Baniahmad et al. 1990; Lobanenkov et al. 1990). CTCF was later shown to be involved in several transcriptional mechanisms such as gene activation (Vostrov et al. 2002) and enhancer blocking (Filippova et al. 2001; Hark et al. 2000; Kanduri et al. 2000; Lutz et al. 2003; Szabó et al. 2000; Tanimoto et al. 2003; Phillips and Corces 2009; Bell et al. 1999; Zlatanova and Caiafa 2009a, 2009b). Insulators block the action of enhancers when positioned between enhancer and promoter. CTCF was found to be required in almost all cases of enhancer blocking tested in vertebrates. This CTCF-mediated enhancer blocking is in many instances conferred by constitutive CTCF action. For some examples however, a modulation of the enhancer blocking activity was documented (Lutz et al. 2003; Weth et al. 2010). One mechanism is achieved by regulation of binding to DNA. It was shown that CTCF is not able to bind to those binding-sites containing methylated CpG sequences. At the imprinting control region (ICR) of the Igf2/H19 locus the binding-site for CTCF on the paternal allele is methylated. This prevents DNA-binding of CTCF, resulting in the loss of enhancer blocking (Bell and Felsenfeld 2000; Chao et al. 2002; Filippova et al. 2001; Hark et al. 2000; Kanduri et al. 2000, 2002; Szabó et al. 2000; Takai et al. 2001). Not only can DNA methylation interfere with CTCF binding to DNA, it was also shown in one report that RNA transcription through the CTCF binding site results in CTCF eviction (Lefevre et al. 2008).

In contrast to these cases most of the DNA sites are not differentially bound by CTCF. Even CTCF interaction with its cofactor cohesin does not seem to differ in different cell types (Schmidt et al. 2010). These results indicate that regulation of CTCF activity might be achieved by neighboring factors bound to DNA. In fact, whole genome analyses of CTCF binding sites identified several classes of neighboring sequences (Dickson et al. 2010; Boyle et al. 2010; Essien et al. 2009). Therefore, in this review we will summarize those results for which a combined action of CTCF with factors bound adjacently was found. These neighboring factors include the RNA polymerases I, II and III, another zinc finger factor VEZF1 and the factors YY1, SMAD, TR and Oct4. Each of these seems to influence, modulate or determine the function of CTCF. Thereby, at least some of the pleiotropic effects of CTCF can be explained.
The role of CTCF in coordinating the expression of single gene loci
Authors: Gillen Austin E , Harris Ann
Published: October 2011

The CCCTC-binding factor (CTCF), which binds insulator elements in vertebrates, also facilitates coordinated gene expression at several gene clusters, including the β-globin, Igf2/H19 (insulin like growth factor 2/H19 noncoding RNA), and major histocompatibility complex (MHC) class II loci. CTCF controls expression of these genes both by enabling insulator function and facilitating higher order chromatin interactions. While the role of CTCF in gene regulation is best studied at these multi-gene loci, there is also evidence that CTCF contributes to the regulated expression of single genes. Here, we discuss how CTCF participates in coordinating gene expression at the CFTR (cystic fibrosis transmembrane conductance regulator) and IFNG (interferon-gamma) loci. We consider the structural similarities between the loci with regard to CTCF-binding elements, the possible interaction between nuclear receptors and CTCF, and the role of CTCF in chromatin looping at these genes. These comparisons reveal a functional model that may be applicable to other single-gene loci that require CTCF for coordinated gene expression.
Genomic relationship between SINE retrotransposons, Pol III–Pol II transcription, and chromatin organization: the journey from junk to jewel
Authors: Lunyak Victoria V. , Atallah Michelle
Published: October 2011

A typical eukaryotic genome harbors a rich variety of repetitive elements. The most abundant are retrotransposons, mobile retroelements that utilize reverse transcriptase and an RNA intermediate to relocate to a new location within the cellular genomes. A vast majority of the repetitive mammalian genome content has originated from the retrotransposition of SINE (100–300 bp short interspersed nuclear elements that are derived from the structural 7SL RNA or tRNA), LINE (7kb long interspersed nuclear element), and LTR (2–3 kb long terminal repeats) transposable element superfamilies. Broadly labeled as “evolutionary junkyard” or “fossils”, this enigmatic “dark matter” of the genome possesses many yet to be discovered properties.
Causes of bimodal stable isotope signatures in the feathers of a molt-migrant songbird
Authors: Bridge Eli S. , Fudickar Adam M. , Kelly Jeffrey F. , Contina Andrea , Rohwer Sievert
Published: October 2011

Stable isotope ratios of hydrogen (δD) and carbon (δ13C) in feathers collected from Painted Buntings ( Passerina ciris (L., 1758)) breeding in the midwestern United States revealed a surprising degree of variation in δD, as well as a clear bimodal signal in δ13C in the innermost primary feather. Because this population does not molt on the breeding grounds, we reasoned that these observations could be due (i) to birds migrating to two (or possibly more) distinct molting areas or (ii) to differences in the timing of molt (as opposed to molt location) relative to arrival at the stopover site. To evaluate these hypotheses, we collected feathers at a molting location in northwestern Mexico, which revealed patterns similar to those from the birds in the US (favoring the second hypothesis above). We suspect that some birds arrive at stopover sites and begin molting before their body tissues equilibrate to the new isoscape so that the first feathers grown represent a blend of materials from the breeding and stopover locations. Other birds may delay molt after arriving at the molting site, allowing them to equilibrate with the local isoscape and produce feathers with isotope signatures of the molting location.
How small is too small? Incubation of large eggs by a small host
Authors: Stewart Rebecca L.M. , Guigueno Mélanie F. , Sealy Spencer G.
Published: October 2011

The Yellow Warbler ( Setophaga petechia (L., 1766)) is among the putative hosts of the Black-billed Cuckoo ( Coccyzus erythropthalmus (Wilson, 1811)), which is hypothesized to have once been an obligate brood parasite. Most parasites lay a small egg relative to their body size, possibly to prevent hosts from discriminating against the larger egg and to facilitate incubation. We tested whether warblers, which lay eggs ~17% of the volume of cuckoo eggs, could have potentially been suitable hosts of Coccyzus cuckoos by determining whether they accept and successfully incubate cuckoo-sized eggs. Warblers accepted 63% (n = 54) of cuckoo-sized eggs added into their nests and successfully incubated eggs as large as cuckoo eggs (surrogate American Robin ( Turdus migratorius L., 1766) eggs). This suggests that the lower limit to host size is not just related to egg size. Warblers are not ideal hosts because they rejected a high frequency of experimental eggs (37%). Nests from which eggs were rejected tended to have smaller volumes than nests at which eggs were accepted. The nest cups of warblers are oval, which may promote egg crowding more than round cups. Factors such as nest size, not host size, influence acceptance or rejection of large eggs by Yellow Warblers.
Changes in relative abundance of snowshoe hares (Lepus americanus) across a 265-year gradient of boreal forest succession
Authors: Hodson James , Fortin Daniel , Bélanger Louis
Published: October 2011

Understory regeneration within canopy gaps in old-growth boreal forests may provide suitable habitat for wildlife typically associated with early-seral stages, leading to an increase in their abundance in late succession. We surveyed a chronosequence of postfire (17–265 years) and postharvest (3–63 years) stands in Canada’s eastern boreal forest to determine whether snowshoe hares ( Lepus americanus Erxleben, 1777) followed a bimodal abundance distribution with stand age that reflects changes in food and cover during postdisturbance succession. A strong peak in relative hare abundance occurred during the first 80 years of succession, with highest faecal pellet densities observed between 40 and 50 years after disturbance. Changes in hare abundance during this period were similar among fire- and clearcut-origin stands and closely tracked changes in lateral cover and vertical cover. Pellet density increased again in stands >180 years. Variation in hare abundance during late succession was partially mediated by gap dynamics, with highest pellet densities in stands occupied by an intermediate proportion of mortality-origin canopy gaps. Hares thus undergo rapid changes in abundance during early succession followed by a much longer period of subtle changes in density as stands develop old-growth structure. Shifting forest age-class distribution induced by forest management could therefore significantly alter regional spatiotemporal dynamics of snowshoe hares.
A domain-specific approach to heterogeneous parallelism
Authors: Chafi Hassan , Sujeeth Arvind K. , Brown Kevin J. , Lee HyoukJoong , Atreya Anand R. , Olukotun Kunle
Published: October 2011

Exploiting heterogeneous parallel hardware currently requires mapping application code to multiple disparate programming models. Unfortunately, general-purpose programming models available today can yield high performance but are too low-level to be accessible to the average programmer. We propose leveraging domain-specific languages (DSLs) to map high-level application code to heterogeneous devices. To demonstrate the potential of this approach we present OptiML, a DSL for machine learning. OptiML programs are implicitly parallel and can achieve high performance on heterogeneous hardware with no modification required to the source code. For such a DSL-based approach to be tractable at large scales, better tools are required for DSL authors to simplify language creation and parallelization. To address this concern, we introduce Delite, a system designed specifically for DSLs that is both a framework for creating an implicitly parallel DSL as well as a dynamic runtime providing automated targeting to heterogeneous parallel hardware. We show that OptiML running on Delite achieves single-threaded, parallel, and GPU performance superior to explicitly parallelized MATLAB code in nearly all cases.
Copperhead
Authors: Catanzaro Bryan , Garland Michael , Keutzer Kurt
Published: October 2011

Modern parallel microprocessors deliver high performance on applications that expose substantial fine-grained data parallelism. Although data parallelism is widely available in many computations, implementing data parallel algorithms in low-level languages is often an unnecessarily difficult task. The characteristics of parallel microprocessors and the limitations of current programming methodologies motivate our design of Copperhead, a high-level data parallel language embedded in Python. The Copperhead programmer describes parallel computations via composition of familiar data parallel primitives supporting both flat and nested data parallel computation on arrays of data. Copperhead programs are expressed in a subset of the widely used Python programming language and interoperate with standard Python modules, including libraries for numeric computation, data visualization, and analysis. In this paper, we discuss the language, compiler, and runtime features that enable Copperhead to efficiently execute data parallel code. We define the restricted subset of Python which Copperhead supports and introduce the program analysis techniques necessary for compiling Copperhead code into efficient low-level implementations. We also outline the runtime support by which Copperhead programs interoperate with standard Python modules. We demonstrate the effectiveness of our techniques with several examples targeting the CUDA platform for parallel programming on GPUs. Copperhead code is concise, on average requiring 3.6 times fewer lines of code than CUDA, and the compiler generates efficient code, yielding 45-100% of the performance of hand-crafted, well optimized CUDA code.
OoOJava
Authors: Jenista James Christopher , Eom Yong hun , Demsky Brian Charles
Published: October 2011

Developing parallel software using current tools can be challenging. Even experts find it difficult to reason about the use of locks and often accidentally introduce race conditions and deadlocks into parallel software. OoOJava is a compiler-assisted approach that leverages developer annotations along with static analysis to provide an easy-to-use deterministic parallel programming model. OoOJava extends Java with a task annotation that instructs the compiler to consider a code block for out-of-order execution. OoOJava executes tasks as soon as their data dependences are resolved and guarantees that the execution of an annotated program preserves the exact semantics of the original sequential program. We have implemented OoOJava and achieved an average speedup of 16.6x on our ten benchmarks.
Inferring ownership transfer for efficient message passing
Authors: Negara Stas , Karmani Rajesh K. , Agha Gul
Published: October 2011

One of the more popular paradigms for concurrent programming is the Actor model of message passing; it has been adopted in one form or another by a number of languages and frameworks. By avoiding a shared local state and instead relying on message passing, the Actor model facilitates modular programming. An important challenge for message passing languages is to transmit messages efficiently. This requires retaining the pass-by-value semantics of messages while avoiding making a deep copy on sequential or shared memory multicore processors. A key observation is that many messages have an ownership transfer semantics; such messages can be sent efficiently using pointers without introducing shared state between concurrent objects. We propose a conservative static analysis algorithm which infers if the content of a message is compatible with an ownership transfer semantics. Our tool, called SOTER (for Safe Ownership Transfer enablER) transforms the program to avoid the cost of copying the contents of a message whenever it can infer the content obeys the ownership transfer semantics. Experiments using a range of programs suggest that our conservative static analysis method is usually able to infer ownership transfer. Performance results demonstrate that the transformed programs execute up to an order of magnitude faster than the original programs.
GRace
Authors: Zheng Mai , Ravi Vignesh T. , Qin Feng , Agrawal Gagan
Published: October 2011

In recent years, GPUs have emerged as an extremely cost-effective means for achieving high performance. Many application developers, including those with no prior parallel programming experience, are now trying to scale their applications using GPUs. While languages like CUDA and OpenCL have eased GPU programming for non-graphical applications, they are still explicitly parallel languages. All parallel programmers, particularly the novices, need tools that can help ensuring the correctness of their programs. Like any multithreaded environment, data races on GPUs can severely affect the program reliability. Thus, tool support for detecting race conditions can significantly benefit GPU application developers. Existing approaches for detecting data races on CPUs or GPUs have one or more of the following limitations: 1) being illsuited for handling non-lock synchronization primitives on GPUs; 2) lacking of scalability due to the state explosion problem; 3) reporting many false positives because of simplified modeling; and/or 4) incurring prohibitive runtime and space overhead. In this paper, we propose GRace, a new mechanism for detecting races in GPU programs that combines static analysis with a carefully designed dynamic checker for logging and analyzing information at runtime. Our design utilizes GPUs memory hierarchy to log runtime data accesses efficiently. To improve the performance, GRace leverages static analysis to reduce the number of statements that need to be instrumented. Additionally, by exploiting the knowledge of thread scheduling and the execution model in the underlying GPUs, GRace can accurately detect data races with no false positives reported. Based on the above idea, we have built a prototype of GRace with two schemes, i.e., GRace-stmt and GRace-addr, for NVIDIA GPUs. Both schemes are integrated with the same static analysis. We have evaluated GRace-stmt and GRace-addr with three data race bugs in three GPU kernel functions and also have compared them with the existing approach, referred to as B-tool. Our experimental results show that both schemes of GRace are effective in detecting all evaluated cases with no false positives, whereas Btool reports many false positives for one evaluated case. On the one hand, GRace-addr incurs low runtime overhead, i.e., 22-116%, and low space overhead, i.e., 9-18MB, for the evaluated kernels. On the other hand, GRace-stmt offers more help in diagnosing data races with larger overhead.
CSX
Authors: Kourtis Kornilios , Karakasis Vasileios , Goumas Georgios , Koziris Nectarios
Published: October 2011

The Sparse Matrix-Vector multiplication (SpMV) kernel scales poorly on shared memory systems with multiple processing units due to the streaming nature of its data access pattern. Previous research has demonstrated that an effective strategy to improve the kernel's performance is to drastically reduce the data volume involved in the computations. Since the storage formats for sparse matrices include metadata describing the structure of non-zero elements within the matrix, we propose a generalized approach to compress metadata by exploiting substructures within the matrix. We call the proposed storage format Compressed Sparse eXtended (CSX). In our implementation we employ runtime code generation to construct specialized SpMV routines for each matrix. Experimental evaluation on two shared memory systems for 15 sparse matrices demonstrates significant performance gains as the number of participating cores increases. Regarding the cost of CSX construction, we propose several strategies which trade performance for preprocessing cost making CSX applicable both to online and offline preprocessing.
Achieving a single compute device image in OpenCL for multiple GPUs
Authors: Kim Jungwon , Kim Honggyu , Lee Joo Hwan , Lee Jaejin
Published: October 2011

In this paper, we propose an OpenCL framework that combines multiple GPUs and treats them as a single compute device. Providing a single virtual compute device image to the user makes an OpenCL application written for a single GPU portable to the platform that has multiple GPU devices. It also makes the application exploit full computing power of the multiple GPU devices and the total amount of GPU memories available in the platform. Our OpenCL framework automatically distributes at run-time the OpenCL kernel written for a single GPU into multiple CUDA kernels that execute on the multiple GPU devices. It applies a run-time memory access range analysis to the kernel by performing a sampling run and identifies an optimal workload distribution for the kernel. To achieve a single compute device image, the runtime maintains virtual device memory that is allocated in the main memory. The OpenCL runtime treats the memory as if it were the memory of a single GPU device and keeps it consistent to the memories of the multiple GPU devices. Our OpenCL-C-to-C translator generates the sampling code from the OpenCL kernel code and OpenCL-C-to-CUDA-C translator generates the CUDA kernel code for the distributed OpenCL kernel. We show the effectiveness of our OpenCL framework by implementing the OpenCL runtime and two source-to-source translators. We evaluate its performance with a system that contains 8 GPUs using 11 OpenCL benchmark applications.
A wait-free NCAS library for parallel applications with timing constraints
Authors: Stellwag Philippe , Scheler Fabian , Krainz Jakob , Schröder-Preikschat Wolfgang
Published: October 2011

We introduce our major ideas of a wait-free, linearizable, and disjoint access parallel NCAS library, called rtNCAS. It focuses the construction of wait-free data structure operations (DSO) in real-time circumstances. rtNCAS is able to conditionally swap multiple independent words (NCAS) in an atomic manner. It allows us, furthermore, to implement arbitrary DSO by means of their sequential specification.
An assessment of information systems service quality using SERVQUAL+
Authors: Gorla Narasimhaiah
Published: October 2011

Service quality of Information Systems (IS) is an important component of IS performance. While previous IS service quality research was based primarily on the version of SERVQUAL that uses a single expectation measure, there have been very few studies on IS service quality based on the enhanced SERVQUAL+ that uses dual expectation measures. The present research evaluates SERVQUAL+ and IS-adapted SERVQUAL+ for their psychometric properties on four scales, namely perceived service (PS), service adequacy (SA), service superiority (SS) and zone of tolerance (ZT), in order to assess their suitability for IS service quality evaluation. Based on nationwide survey data of 337 respondents, the two instruments were analyzed for construct reliability, convergent and divergent criteria, LISREL-based CFA analyses of goodness-of-fit, indicator loadings, construct composite reliability, average variance extracted, and unidimensionality. Our results show that SA and ZT have better psychometric properties compared to SS, the traditional gap measure of service quality. The tangibles dimension contributes adequately towards IS service quality measurement and may not be discarded. While both the instruments demonstrate good psychometric properties on most criteria, IS-adapted SERVQUAL+ is marginally superior to SERVQUAL+. However, neither instrument satisfies the discrimination criteria and unidimensionality property in any of the four scales.
Heterogeneity of IT employees
Authors: Lo Janice , Riemenschneider Cindy
Published: October 2011

The retention of existing IT employees is crucial due to the expected shortage of the IT labor force in the U.S., Canada, and European countries. While much of the extant IT turnover literature implicitly assumes that IT employees are homogeneous, we contend that they are a diverse group and that exploring the group in depth would reveal further insights into why employees turnover. We examined a sample of employees by IT job type in a turnover model of the antecedents and impacts of perceived organizational support (POS), which is another infrequently studied concept in the literature but is a potentially important predictor of turnover. A survey of 302 IT employees at a large U.S.-based company showed that these employees are in fact diverse. The relationships between role ambiguity and POS and work schedule flexibility and POS were found to be significant for managerial employees, but not for technically-oriented employees. The relationship between career accommodations and POS, however, was found to be significant for technically-oriented employees, but not managerial employees. As a whole, this study suggests that by combining all IT employees together in our analyses, we may forego some of the unique insights about these employees that we can otherwise cultivate to strengthen the bond between the organization and its employees and to enhance our existing IT turnover literature. The results of this study provide implications for organizations on how they can better balance the tactics they use to retain their valued IT employees. IT managers can be in a better position to focus on building relationships with their employees based on what is generally important to those employees.
Encouraging participation in virtual communities through usability and sociability development
Authors: Lu Xianghua , Phang Chee Wei , Yu Jie
Published: October 2011

Usability and sociability are two characteristics of a virtual community that are critical to its success. This study aims to explore how usability and sociability of virtual communities can be developed in order to encourage members' continuous participation in these communities. A theoretical model is proposed to explain the effects of factors related to usability and sociability on members' continuous participation through the motivational beliefs of perceived usefulness, perceived enjoyment and sense of belonging. Data was collected from members of five popular leisure-oriented virtual communities in China. The results show that both perceived enjoyment and sense of belonging impact members' continuous participation intention.

Among the usability-and sociability-related factors, we find that information service quality is the most critical factor that encourages members to continuously participate in virtual communities, while interaction support quality, incentive policy, and event organization also have positive effects on members' continuous participation intention via perceived enjoyment and sense of belonging. Surprisingly, leaders' involvement has no impact on members' continuous participation. Implications of the study's findings for both research and practice are discussed.
Cache analysis in presence of pointer-based data structures
Authors: Dudziak Tomasz , Herter Jörg
Published: October 2011

Cache analysis plays a crucial part when analyzing the WCET of an application. This paper presents ongoing work aiming at a precise cache analysis in the presence of pointer-based, heap-allocated data structures. The proposed analysis achieves precision by augmenting its abstract cache states with information about the structure of the program's allocated objects as well as a short term access history of these objects. This additional information is derived from an adapted shape analysis that serves as an pre-analysis phase to our actual cache analysis.
Swapping to reduce preemptions and migrations in EKG
Authors: Nelissen Geoffrey , Funk Shelby , Goossens Joël , Milojevic Dragomir
Published: October 2011

EKG is a multiprocessor scheduling algorithm which is optimal for the schedule of real-time periodic tasks with implicit deadlines. It adheres to the deadline partitioning fair (DP-Fair) approach. However, it was shown in recent studies that the systematic execution of some tasks inherent in such approaches, significantly reduce the usability of this algorithm. Hence, we propose a swapping algorithm with the aim of reducing the number of preemptions and migrations incurred by EKG. This algorithm should enhance the practicality of EKG while keeping its optimality.
ACM copyrights and plagiarism
Authors: Walker Henry M.
Published: October 2011

As authors consider forums for publication, some common questions involve copyright: Who owns the copyright? May I post a copy of my piece on the Web? Could I publish the material in another publication?
A unified user preference based framework for video content personalization
Authors: Liu Chunxi
Published: October 2011

ScientifiCareers (http://www.scientificareers.com/) is a project dedicated to job opportunities for young researchers in the field of Multimedia.
Montmorillonite Clay-Based Polyurethane Nanocomposite As Local Triamcinolone Acetonide Delivery System
Authors: Pinto Flávia Carmo Horta , Silva-Cunha Armando , Pianetti Gerson Antônio , Ayres Eliane , Oréfice Rodrigo Lambert , Da Silva Gisele Rodrigues
Published: October 2011

Biodegradable polyurethane was synthesized by preparing aqueous polyurethane dispersion having poly(caprolactone) and poly(ethylene glycol) as soft segments. Montmorillonite particles were delaminated within the waterborne polyurethane to produce a nanocomposite. The triamcinolone acetonide (TA), an important corticoid drug, was dispersed into the nanocomposite followed by a drying step to produce an implantable drug delivery system. Infrared (FTIR) results demonstrated that the original chemical structure of the TA was preserved after incorporation into the nanocomposite. Wide angle (WAXS) and small angle X-ray scattering (SAXS) results suggested that TA and clay do not dramatically change the morphology phase of the polymer although they can interact with each other. The presence of montmorillonite particles in the nanocomposite reduced the rate of TA release as compared to the pure polyurethane and enhanced the mechanical properties of the polymer. The overall results indicate that montmorillonite clay-based polyurethane nanocomposite could be potentially applied as local TA delivery system.
The LOBI Integral System Test Facility Experimental Programme
Authors: Addabbo Carmelo , Annunziato Alessandro
Published: October 2011

The LOBI project has been carried out in the framework of the European Commission Reactor Safety Research Programme in close collaboration with institutional and/or industrial research organizations of EC member countries. The primary objective of the research programme was the generation of an experimental data base for the assessment of the predictive capabilities of thermal-hydraulic system codes used in pressurised water reactor safety analysis. Within this context, experiments have been conducted in the LOBI integral system test facility designed, constructed, and operated (1979–1991) at the Ispra Site of the Joint Research Centre. This paper provides a historical perspective and summarizes major achievements of the research programme which has represented an effective approach to international collaboration in the field of reactor safety research and development. Emphasis is also placed on knowledge management aspects of the acquired experimental data base and on related online open access/retrieval user functionalities.
Examining Stools for Colon Cancer Prevention: What Are We Really Looking for?
Authors: Byers Tim
Published: October 2011

Fecal immunochemical testing (FIT) is superior to guiac-based testing if we are looking for blood in stools, as it has better one-time colorectal cancer sensitivity and specificity and better patient acceptance. In this issue of the journal, Cai and colleagues (beginning on page 1572) and Khalid-de Bakker and colleagues (beginning on page 1563) present new information about the one-time test performance of FIT. FIT will have a growing appeal to providers and health care systems as resources for clinical preventive services shrink and as incentives to expand colorectal screening rates increase, but there are good reasons to be cautious about the temptation to organize new FIT screening programs. Colorectal screening has two potential objectives: To find cancers in an earlier, more-treatable stage and to find and remove adenomas to prevent cancers from forming in the first place. Because most adenomas, even advanced adenomas, do not bleed, tests designed to identify occult blood in the stool are better for detecting colorectal cancer, whereas direct endoscopic visualization of the colorectum is better for prevention. Even if advanced adenomas did commonly bleed, low compliance with repeat annual testing will seriously erode the benefit of FIT. Cancer Prev Res; 4(10); 1531–3. ©2011 AACR.
Drosophila as a Developmental Paradigm of Regressive Brain Evolution: Proof of Principle in the Visual System
Authors: Friedrich Markus
Published: October 2011

Evolutionary developmental biology focuses heavily on the constructive evolution of body plan components, but there are many instances such as parasitism, cave adaptation, or postembryonic growth rate optimization where evolutionary regression is of adaptive value. This is particularly true in the nervous system because of its massive energy costs. However, comparatively little effort has thus far been made to understand the evolutionary developmental trajectories of adaptive nervous system reduction. This review focuses on the organization and evolution of the Drosophila larval brain, which represents an exceptional example of miniaturization, most dramatically in the visual system. It is specifically discussed how the dependency of outer optic lobe development on retinal innervation can be assumed to have facilitated a first evolutionary phase of larval visual system reduction. Afferent input-contingent development of neu- ral compartments very likely plays a widespread role in adaptive brain evolution. Understanding the complete deconstruction of the larval optic neuropiles in Drosophila awaits expanded comparative analysis but has the promise to inform about further developmental trajectories and mechanisms underlying regressive evolution of the brain.
Liver Transplantation for Hepatocellular Carcinoma – Is There a Risk of Recurrence Caused by Intraoperative Blood Salvage Autotransfusion?
Authors: Foltys D. , Zimmermann T. , Heise M. , Kaths M. , Lautem A. , Wisser G. , Weiler N. , Hoppe-Lotichius M. , Hansen T. , Otto G.
Published: October 2011

Background/Aims: The use of intraoperative blood salvage autotransfusion (IBSA) during surgical approaches may contribute to tumour cell dissemination. Therefore, IBSA should be avoided in cases of malignancy. However, the risks of IBSA might be acceptable in liver transplantation (LT) for selected small hepatocellular carcinoma (HCC). Methods: In total, 136 recipients of LT with histologically proven HCC in the explanted liver were included in this analysis. With regard to tumour recurrence, 40 patients receiving IBSA despite HCC (IBSA group) were compared to 96 patients without IBSA (non-IBSA group). Results: Milan criteria as assessed in the explanted liver were fulfilled in 24 of 40 IBSA patients and 58 of 96 non-IBSA patients (p = 0.85). Five of 40 patients in the IBSA group and 18 of 96 patients in the non-IBSA group experienced tumour recurrence (p = 0.29). In spite the theoretical risk of tumour cell dissemination, the recurrence rate was not increased in the IBSA group. Conclusion: Our results indicate that IBSA does not modify the risk of HCC recurrence. Therefore, in highly selected HCC patients undergoing LT, the use of IBSA appears to be justified.
Water Extract of Gromwell (Lithospermum erythrorhizon) Enhances Migration of Human Keratinocytes and Dermal Fibroblasts with Increased Lipid Synthesis in an in vitro Wound Scratch Model
Authors: Kim H. , Kim J. , Park J. , Kim S.H. , Uchida Y. , Holleran W.M. , Cho Y.
Published: October 2011

Background: Although organic extracts of gromwell (Lithospermum erythrorhizon) have been shown to promote wound healing, the wound healing effects of water extracts of gromwell (WG) that are commonly used in traditional remedies have not been elucidated. Objective: We investigated whether WG promotes the migration and/or proliferation of cultured human keratinocytes (CHK) or dermal fibroblasts in parallel with increases in lipid synthesis during in vitro wound healing. Methods: CHK or fibroblasts were treated with 1–1,000 µg/ml WG for up to 48 h following scratch wound formation. Cell migration was assessed by measuring coverage (in percent) from the wound margin, while cell proliferation and lipid synthesis were determined by [3H]thymidine incorporation into DNA fractions, and [3H]palmitate or [3H]serine incorporation into lipid fractions, respectively. Results: Low-dose WG (1 µg/ml) enhanced the wound coverage for both CHK and fibroblasts at 24 h, while cell proliferation was not altered in either cell types. Synthesis of both total lipids and individual lipid classes, including phospholipids, sphingolipids and neutral lipids, were found to be increased at 24 h in CHK treated with 1 µg/ml WG; in similarly treated fibroblasts, only the syntheses of sphingolipids (such as ceramides and glucosylceramides), but not other lipid species, were significantly increased. In contrast, a higher dose of WG (10–1,000 µg/ml) did not enhance wound coverage, and 100 µg/ml WG neither altered cell proliferation nor lipid synthesis in both CHK and fibroblasts. Conclusion: Low-dose WG (1 µg/ml) enhances the migration of both CHK and fibroblasts with increased lipid synthesis in an in vitro wound scratch model.
Imatinib Mesylate Therapy Induces Reduction in Neutrophil Gelatinase-Associated Lipocalin Serum Levels and Increase in Leptin Concentrations in Chronic Myeloid Leukemia Patients in Molecular Remission
Authors: Alonci Andrea , Allegra Alessandro , Russo Sabina , Penna Giuseppa , Bellomo Giacomo , D’Angelo Arianna , Campo Salvatore , Cannavò Antonino , Centorrino Raffaella , Musolino Caterina
Published: October 2011

The aim of the present study was to determine serum levels of neutrophil gelatinase-associated lipocalin (NGAL) and leptin in patients with chronic myeloid leukemia (CML) at diagnosis and after imatinib therapy when patients achieved a complete molecular remission. The study was conducted on 22 patients with CML in the chronic phase and 10 healthy subjects. The median serum NGAL levels in CML patients at diagnosis were significantly higher compared to age-matched controls. After imatinib therapy, all patients achieved complete molecular remission and NGAL levels decreased and were found significantly lower with respect to the baseline. No significant correlations were found between NGAL levels and other disease parameters. Before imatinib therapy, the median blood leptin levels were not significantly different from those of controls. After therapy with imatinib, all patients in molecular remission presented an increase in leptin levels. Future research is eagerly awaited as it may demonstrate the real role of NGAL and leptin in the onset and progression of CML.