bluuebunny/crossref_metadata_2025 huggingface dataset:
Superimposing dynamic range
Authors: Bimber Oliver , Iwai Daisuke
Published: December 2008

We present a simple and cost-efficient way of extending contrast, perceived tonal resolution, and color space of reflective media, such as paper prints, hardcopy photographs, or electronic paper displays. A calibrated projector-camera system is applied for automatic registration, radiometric scanning and superimposition. A second modulation of the projected light on the surface of such media results in a high dynamic range visualization. This holds application potential for a variety of domains, such as radiology, astronomy, optical microscopy, conservation and restoration of historic art, modern art and entertainment installations.
Adaptive cutaways for comprehensible rendering of polygonal scenes
Authors: Burns Michael , Finkelstein Adam
Published: December 2008

In 3D renderings of complex scenes, objects of interest may be occluded by those of secondary importance. Cutaway renderings address this problem by omitting portions of secondary objects so as to expose the objects of interest. This paper introduces a method for generating cutaway renderings of polygonal scenes at interactive frame rates, using illustrative and non-photorealistic rendering cues to expose objects of interest in the context of surrounding objects. We describe a method for creating a view-dependent cutaway shape along with modifications to the polygonal rendering pipeline to create cutaway renderings. Applications for this technique include architectural modeling, path planning, and computer games.
Line-art illustration of dynamic and specular surfaces
Authors: Kim Yongjin , Yu Jingyi , Yu Xuan , Lee Seungyong
Published: December 2008

Line-art illustrations are effective tools for conveying shapes and shading of complex objects. We present a set of new algorithms to render line-art illustrations of dynamic and specular (reflective and refractive) surfaces. We first introduce a real-time principal direction estimation algorithm to determine the line stroke directions on dynamic opaque objects using neighboring normal ray triplets. To render reflections or refractions in a line-art style, we develop a stroke direction propagation algorithm by using multi-perspective projections to propagate the stroke directions from the nearby opaque objects onto specular surfaces. Finally, we present an image-space stroke mapping method to draw line strokes using the computed or propagated stroke directions. We implement these algorithms using a GPU and demonstrate real-time illustrations of scenes with dynamic and specular 3D models in line-art styles.
Interactive 3D architectural modeling from unordered photo collections
Authors: Sinha Sudipta N. , Steedly Drew , Szeliski Richard , Agrawala Maneesh , Pollefeys Marc
Published: December 2008

We present an interactive system for generating photorealistic, textured, piecewise-planar 3D models of architectural structures and urban scenes from unordered sets of photographs. To reconstruct 3D geometry in our system, the user draws outlines overlaid on 2D photographs. The 3D structure is then automatically computed by combining the 2D interaction with the multi-view geometric information recovered by performing structure from motion analysis on the input photographs. We utilize vanishing point constraints at multiple stages during the reconstruction, which is particularly useful for architectural scenes where parallel lines are abundant. Our approach enables us to accurately model polygonal faces from 2D interactions in a single image. Our system also supports useful operations such as edge snapping and extrusions.

Seamless texture maps are automatically generated by combining multiple input photographs using graph cut optimization and Poisson blending. The user can add brush strokes as hints during the texture generation stage to remove artifacts caused by unmodeled geometric structures. We build models for a variety of architectural scenes from collections of up to about a hundred photographs.
Fast animation of turbulence using energy transport and procedural synthesis
Authors: Narain Rahul , Sewall Jason , Carlson Mark , Lin Ming C.
Published: December 2008

We present a novel technique for the animation of turbulent fluids by coupling a procedural turbulence model with a numerical fluid solver to introduce subgrid-scale flow detail. From the large-scale flow simulated by the solver, we model the production and behavior of turbulent energy using a physically motivated energy model. This energy distribution is used to synthesize an incompressible turbulent velocity field, whose features show plausible temporal behavior through a novel Lagrangian approach for advected noise. The synthesized turbulent flow has a dynamical effect on the large-scale flow, and produces visually plausible detailed features on both gaseous and free-surface liquid flows. Our method is an order of magnitude faster than full numerical simulation of equivalent resolution, and requires no manual direction.
Emerging marketsLabor supply in the Indian IT industry
Authors: Aggarwal Alok
Published: December 2008

Exploring the evolving dynamics and interconnectedness of India's educational system and its IT work force
.
IT policyAdvising policymakers is more than just providing advice
Authors: Wilson Cameron , Harsha Peter
Published: December 2008

What are the factors that make certain advisory committee reports successful while others are not?
Kode viciousPermanence and change
Authors: Neville-Neil George V.
Published: December 2008

Highlighting the importance of doing one's best in view of code longevity and the impermanence of the changineer
.
CTO Roundtable: Virtualization Part II
Authors: Creeger Mache
Published: December 2008

When it comes to virtualization platforms, experts say focus first on the services to be delivered.
Ontologies and the semantic web
Authors: Horrocks Ian
Published: December 2008

How ontologies provide the semantics, as explained here with the help of Harry Potter and his owl Hedwig.
Open information extraction from the web
Authors: Etzioni Oren , Banko Michele , Soderland Stephen , Weld Daniel S.
Published: December 2008

Targeted IE methods are transforming into open-ended techniques.
Breaking the memory wall in MonetDB
Authors: Boncz Peter A. , Kersten Martin L. , Manegold Stefan
Published: December 2008

In the past decades, advances in speed of commodity CPUs have far outpaced advances in RAM latency. Main-memory access has therefore become a performance bottleneck for many computer applications; a phenomenon that is widely known as the "memory wall." In this paper, we report how research around the MonetDB database system has led to a redesign of database architecture in order to take advantage of modern hardware, and in particular to avoid hitting the memory wall. This encompasses (i) a redesign of the query execution model to better exploit pipelined CPU architectures and CPU instruction caches; (ii) the use of columnar rather than row-wise data storage to better exploit CPU data caches; (iii) the design of new
cache-conscious
query processing algorithms; and (iv) the design and automatic calibration of memory cost models to choose and tune these cache-conscious algorithms in the query optimizer.
Exterminator
Authors: Novark Gene , Berger Emery D. , Zorn Benjamin G.
Published: December 2008

Programs written in C and C++ are susceptible to memory errors, including buffer overflows and dangling pointers. These errors, which can lead to crashes, erroneous execution, and security vulnerabilities, are notoriously costly to repair. Tracking down their location in the source code is difficult, even when the full memory state of the program is available. Once the errors are finally found, fixing them remains challenging: even for critical security-sensitive bugs, the average time between initial reports and the issuance of a patch is nearly 1 month.

We present Exterminator, a system that automatically corrects heap-based memory errors without programmer intervention. Exterminator exploits randomization to pinpoint errors with high precision. From this information, Exterminator derives
runtime patches
that fix these errors both in current and subsequent executions. In addition, Exterminator enables collaborative bug correction by merging patches generated by multiple users. We present analytical and empirical results that demonstrate Exterminator's effectiveness at detecting and correcting both injected and real faults.
Variant Chinese Domain Name Resolution
Authors: Lin Jeng-Wei , Ho Jan-Ming , Tseng Li-Ming , Lai Feipei
Published: December 2008

Many efforts in past years have been made to lower the linguistic barriers for non-native English speakers to access the Internet. Internet standard RFC 3490, referred to as IDNA (Internationalizing Domain Names in Applications), focuses on access to IDNs (Internationalized Domain Names) in a range of scripts that is broader in scope than the original ASCII. However, the use of character variants that have similar appearances and/or interpretations could create confusion. A variant IDL (Internationalized Domain Label), derived from an IDL by replacing some characters with their variants, should match the original IDL; and thus a variant IDN does. In RFC 3743, referred to as JET (Joint Engineering Team) Guidelines, it is suggested that zone administrators model this concept of equivalence as an atomic IDL package. When an IDL is registered, an IDL package is created that contains its variant IDLs generated according to the zone-specific Language Variant Tables (LVTs). In addition to the registered IDL, the name holder can request the domain registry to activate some of the variant IDLs, free or by an extra fee. The activated variant IDLs are stored in the zone files, and thus become resolvable. However, an issue of scalability arises when there is a large number of variant IDLs to be activated.

In this article, the authors present a resolution protocol that resolves the variant IDLs into the registered IDL, specifically for Han character variants. Two Han characters are said to be variants of each other if they have the same meaning and are pronounced the same. Furthermore, Han character variants usually have similar appearances. It is not uncommon that a Chinese IDL has a large number of variant IDLs. The proposed protocol introduces a new RR (resource record) type, denoted as VarIdx RR, to associate a variant expression of the variant IDLs with the registered IDL. The label of the VarIdx RR, denoted as the variant index, is assigned by an indexing function that is designed to give the same value to all of the variant IDLs enumerated by the variant expression. When one of the variant IDLs is accessed, Internet applications can compute the variant index, look up the VarIdx RRs, and resolve the variant IDL into the registered IDL.

The authors examine two sets of Chinese IDLs registered in TWNIC and CNNIC, respectively. The results show that for a registered Chinese IDL, a very small number of VarIdx RRs, usually one or two, are sufficient to activate all of its variant IDLs. The authors also represent a Web redirection service that employs the proposed resolution protocol to redirect a URL addressed by a variant IDN to the URL addressed by the registered IDN. The experiment results show that the proposed protocol successfully resolves the variant IDNs into the registered IDNs.
Boosting Chinese Question Answering with Two Lightweight Methods
Authors: Lee Cheng-Wei , Day Min-Yuh , Sung Cheng-Lung , Lee Yi-Hsun , Jiang Tian-Jian , Wu Chia-Wei , Shih Cheng-Wei , Chen Yu-Ren , Hsu Wen-Lian
Published: December 2008

Question Answering (QA) research has been conducted in many languages. Nearly all the top performing systems use heavy methods that require sophisticated techniques, such as parsers or logic provers. However, such techniques are usually unavailable or unaffordable for under-resourced languages or in resource-limited situations. In this article, we describe how a top-performing Chinese QA system can be designed by using lightweight methods effectively. We propose two lightweight methods, namely the Sum of Co-occurrences of Question and Answer Terms (SCO-QAT) and Alignment-based Surface Patterns (ABSPs). SCO-QAT is a co-occurrence-based answer-ranking method that does not need extra knowledge, word-ignoring heuristic rules, or tools. It calculates co-occurrence scores based on the passage retrieval results. ABSPs are syntactic patterns trained from question-answer pairs with a multiple alignment algorithm. They are used to capture the relations between terms and then use the relations to filter answers. We attribute the success of the ABSPs and SCO-QAT methods to the effective use of local syntactic information and global co-occurrence information.

By using SCO-QAT and ABSPs, we improved the RU-Accuracy of our testbed QA system, ASQA, from 0.445 to 0.535 on the NTCIR-5 dataset. It also achieved the top 0.5 RU-Accuracy on the NTCIR-6 dataset. The result shows that lightweight methods are not only cheaper to implement, but also have the potential to achieve state-of-the-art performances.
Reducing register pressure in SMT processors through L2-miss-driven early register release
Authors: Sharkey Joseph J. , Loew Jason , Ponomarev Dmitry V.
Published: December 2008

The register file is one of the most critical datapath components limiting the number of threads that can be supported on a simultaneous multithreading (SMT) processor. To allow the use of smaller register files without degrading performance, techniques that maximize the efficiency of using registers through aggressive register allocation/deallocation can be considered. In this article, we propose a novel technique to early deallocate physical registers allocated to threads which experience L2 cache misses. This is accomplished by speculatively committing the load-independent instructions and deallocating the registers corresponding to the previous mappings of their destinations, without waiting for the cache miss request to be serviced. The early deallocated registers are then made immediately available for allocation to instructions within the same thread as well as within other threads, thus improving the overall processor throughput. On the average across the simulated mixes of multiprogrammed SPEC 2000 workloads, our technique results in 33% improvement in throughput and 25% improvement in terms of harmonic mean of weighted IPCs over the baseline SMT with the state-of-the-art DCRA policy. This is achieved without creating checkpoints, maintaining per-register counters of pending consumers, performing tag rebroadcasts, register remappings, and/or additional associative searches.
Exploiting selective placement for low-cost memory protection
Authors: Mehrara Mojtaba , Austin Todd
Published: December 2008

Many embedded processing applications, such as those found in the automotive or medical field, require hardware designs that are at the same time low cost and reliable. Traditionally, reliable memory systems have been implemented using coded storage techniques, such as ECC. While these designs can effectively detect and correct memory faults such as transient errors and single-bit defects, their use bears a significant cost overhead. In this article, we propose a novel partial memory protection scheme that provides high-coverage fault protection for program code and data, but with much lower cost than traditional approaches. Our approach profiles program code and data usage to assess which program elements are most critical to maintaining program correctness. Critical code and variables are then placed into a limited protected storage resources. To ensure high coverage of program elements, our placement technique considers all program components simultaneously, including code, global variables, stack frames, and heap variables. The fault coverage of our approach is gauged using Monte Carlo fault-injection experiments, which confirm that our technique provides high levels of fault protection (99% coverage) with limited memory protection resources (36% protected area).
Speculative return address stack management revisited
Authors: Vandierendonck Hans , Seznec André
Published: December 2008

Branch prediction feeds a speculative execution processor core with instructions. Branch mispredictions are inevitable and have negative effects on performance and energy consumption. With the advent of highly accurate conditional branch predictors, nonconditional branch instructions are gaining importance.

In this article, we address the prediction of procedure returns. On modern processors, procedure returns are predicted through a return address stack (RAS). The overwhelming majority of the return mispredictions are due to RAS overflows and/or overwriting the top entries of the RAS on a mispredicted path. These sources of misprediction were addressed by previously proposed speculative return address stacks [Jourdan et al. 1996; Skadron et al. 1998]. However, the remaining misprediction rate of these RAS designs is still significant when compared to state-of-the-art conditional predictors.

We present two low-cost corruption detectors for RAS predictors. They detect RAS overflows and wrong path corruption with 100% coverage. As a consequence, when such a corruption is detected, another source can be used for predicting the return. On processors featuring a branch target buffer (BTB), this BTB can be used as a free backup predictor for predicting returns when corruption is detected.

Our experiments show that our proposal can be used to improve the behavior of all previously proposed speculative RASs. For instance, without any specific management of the speculative states on the RAS, an 8-entry BTB-backed up RAS achieves the same performance level as a state-of-the-art, but complex, 64-entry self-checkpointing RAS [Jourdan et al. 1996]. Therefore, our proposal can be used either to improve the performance of the processor or to reduce its hardware complexity.
Hierarchical routing in ad hoc networks using k-dominating sets
Authors: Rieck Michael Q. , Dhar Subhankar
Published: December 2008

In this article, the notion of a k-SPR set from previous work is extended to the context of an edge-weighted graph. Under a reasonable assumption, such a set is still k-dominating, and k-hop connected. When a decreasing sequence of such sets is used, together with a hybrid route discovery strategy (partly proactive, partly reactive), the result is a highly scalable and efficient, minimal path routing protocol.
Biophysical Support for Functionally Distinct Cell Types in the Frontal Eye Field
Authors: Cohen Jeremiah Y. , Pouget Pierre , Heitz Richard P. , Woodman Geoffrey F. , Schall Jeffrey D.
Published: December 2008

Numerous studies have described different functional cell types in the frontal eye field (FEF), but the reliability of the distinction between these types has been uncertain. Studies in other brain areas have described specific differences in the width of action potentials recorded from different cell types. To substantiate the functionally defined cell types encountered in FEF, we measured the width of spikes of visual, movement, and visuomovement types of FEF neurons in macaque monkeys. We show that visuomovement neurons had the thinnest spikes, consistent with a role in local processing. Movement neurons had the widest spikes, consistent with their role in sending eye movement commands to subcortical structures such as the superior colliculus. Visual neurons had wider spikes than visuomovement neurons, consistent with their role in receiving projections from occipital and parietal cortex. These results show how structure and function of FEF can be linked to guide inferences about neuronal architecture.
Peyronie's Reconstruction for Maximum Length and Girth Gain: Geometrical Principles
Authors: Egydio Paulo H. , Sansalone Salvatore
Published: December 2008

Peyronie's disease has been associated with penile shortening and some degree of erectile dysfunction. Surgical reconstruction should be based on giving a functional penis, that is, rectifying the penis with rigidity enough to make the sexual intercourse. The procedure should be discussed preoperatively in terms of length and girth reconstruction in order to improve patient satisfaction. The tunical reconstruction for maximum penile length and girth restoration should be based on the maximum length of the dissected neurovascular bundle possible and the application of geometrical principles to define the precise site and size of tunical incision and grafting procedure. As penile rectification and rigidity are required to achieve complete functional restoration of the penis and 20 to 54% of patients experience associated erectile dysfunction, penile straightening alone may not be enough to provide complete functional restoration. Therefore, phosphodiesterase inhibitors, self-injection, or penile prosthesis may need to be added in some cases.
Small Bowel Tumors: Clinical Presentation, Prognosis, and Outcome in 33 Patients in a Tertiary Care Center
Authors: Farhat Mirna H. , Shamseddine Ali I. , Barada Kassem A.
Published: December 2008

Introduction. Small bowel cancers are rare. Accumulation of data regarding their clinical presentation, pathologic features, prognostic factors, treatment modalities, and outcome is difficult.Methods. This is a retrospective study of the medical records of 33 patients with small bowel cancers treated at the American University of Beirut-Medical Center over a 20-year period.Results. The study included 25 males (76%) and 8 females (24%). Median age at presentation was 56 years. Most common symptoms were abdominal pain (66.7%) and weight loss (57.6%). Thirteen patients presented with abdominal emergencies (39.3%). Lymphoma was the most common malignant tumor (36.4%), followed by adenocarcinoma (33.3%), leiomyosarcoma (15.2%), gastrointestinal stromal tumors (12.1%), and neuroendocrine tumors (3.0%). Tumors were located in the duodenum in 30% of patients, jejunum in 33%, and ileum in 36%. Resectability rate was 72.7% and curative R0 resection was achieved in 54.1% (13/24) of patients. 5-year survival of the 33 patients was 24.2%.Conclusion. Small bowel cancers are difficult to diagnose because of the nonspecific symptoms. Most patients present with advanced disease and have poor prognosis. Adenocarcinoma and duodenal location have the worst 5-year survival in contrast to stromal tumors and those with ileal location which have the best survival.
Quasi‐Steady Analytical Model Benchmark of an Impulse Turbine for Wave Energy Extraction
Authors: Thakker A. , Jarvis J. , Sahed A.
Published: December 2008

This work presents a mean line analysis for the prediction of the performance and aerodynamic loss of axial flow impulse turbine
wave energy extraction, which can be easily incorporated into the turbine design program. The model is based on the momentum
principle and the well‐known Euler turbine equation. Predictions of torque, pressure drop, and turbine efficiency showed favorable
agreement with experimental results. The variation of the flow incidence and exit angles with the flow coefficient has been reported
for the first time in the field of wave energy extraction. Furthermore, an optimum range of upstream guide vanes setting up angle
was determined, which optimized the impulse turbine performance prediction under movable guide vanes working condition.
Preservation of Cavernosal Erectile Function after Soft Penile Prosthesis Implant in Peyronie's Disease: Long-Term Followup
Authors: Grasso Marco , Lania Caterina , Fortuna Flavio , Blanco Salvatore , Piacentini Igor
Published: December 2008

The aim of this retrospective study is to evaluate the long-term followup of soft penile SSDA prosthesis, without plaque surgery in the treatment of Peyronie's disease. This study included 12 men with Peyronie's disease who underwent placement of a penile prosthesis. All patients were followed for at least 6 years. Prosthesis straightened the penile shaft in all cases, restoring patient sexual satisfaction. No operative or postoperative complications occurred, and no reoperations were needed. All patients have undergone further examination with basal and dynamic eco color Doppler. The findings are encouraging as the penis preserves the ability to enhance the tumescence and penile girth. We can conclude that SSDA penile prosthesis is safe and effective in Peyronie's disease.
Serum Amyloid P Component as a Biomarker in Mild Cognitive Impairment and Alzheimer’s Disease
Authors: Verwey Nicolaas A. , Schuitemaker Alie , van der Flier Wiesje M. , Mulder Sandra D. , Mulder Cees , Hack C. Erik , Scheltens Philip , Blankenstein Marinus A. , Veerhuis Robert
Published: December 2008

Background: Serum amyloid P component (SAP), present in amyloid-β (Aβ) plaques in Alzheimer’s disease (AD), may protect Aβ deposits against proteolysis, thereby promoting plaque formation. The aim was to investigate if SAP levels in cerebrospinal fluid (CSF) and serum can be used to discriminate controls, AD and mild cognitive impairment (MCI) patients, and to identify incipient AD among MCI patients. Methods: SAP levels in CSF and serum were determined in 30 controls, 67 MCI and 144 AD patients. At follow-up, 39 MCI patients had progressed to dementia, while 25 had remained stable (mean follow-up time: 2.6 ± 1.0 and 2.1 ± 0.8 years). Results: Cross-sectionally no differences were found in SAP levels in CSF and serum between the groups. MCI patients that had progressed to dementia at follow-up had lower CSF SAP levels (13 mg/l, range 3.3–199.3 mg/l) than MCI nonprogressors (20.2 mg/l, range 7.0–127.7 mg/l; p < 0.05). A low CSF SAP level was associated with a 2-fold increased risk of progression to AD (hazard ratio = 2.2; 95% confidence interval = 0.9–5.4). Conclusion: Our data suggest that measurement of CSF SAP levels can aid in the identification of incipient AD among MCI patients.
Foot Disorders and Falls in Older Persons
Authors: Chaiwanichsiri Dootchai , Janchai Siriporn , Tantisiriwat Natthiya
Published: December 2008

Background: Fall rates are high among older people even in the healthy population. An aging foot may affect ambulatory function and increase the risk of fall(s). Objective: To study foot musculoskeletal disorders, falls and associated factors in healthy elderly subjects. Methods: Healthy volunteers aged 60–80 years who were independent in self-care and walking were recruited from urban Bangkok. Trained physicians evaluated health status, foot problems, and fall(s) history of all subjects. Walking performance was assessed using the ‘Timed Get Up & Go’ test and 6-m walking speed. Footprints were taken from the standing position. Foot dimensions and footwear were also measured by certified orthotists. Associated factors of foot disorders and falls were analyzed. Results: There were 213 subjects: 108 men, 105 women with a mean age of 68.6 ± 5.4 years. Foot deformities presented in 87% and were not significantly associated with walking performance or falls. Foot pain was found in 14% with a male:female sex ratio of 1:4. The causes of pain were plantar fasciitis, hallux valgus, callus, metatarsalgia, and inappropriate footwear. Subjects with foot pain had slower walking speed (1.14 ± 0.12 vs. 1.19 ± 0.12 m/s, p = 0.056). Falls were reported in 29.5% of women and 12.9% of men (p = 0.004). Multivariate analyses demonstrated that fall risk factors were female gender (OR = 2.4, 95% CI = 1.13–5.12), plantar fasciitis (OR = 6.8, 95% CI = 1.52–31.02), and knee osteoarthritis (OR = 3.6, 95% CI = 1.71–7.59). Subgroup analyses revealed that visual deficit was associated with falls in women (OR = 4.7, 95% CI = 1.75–12.73), and impaired foot protective sensation was associated with falls in men (OR = 5.1, 95% CI = 1.46–18.38). Conclusions: Aging foot deformities presented different characteristics among genders and were mostly asymptomatic. Foot pain, especially from plantar fasciitis, increased risk of falls in healthy older persons. Foot assessment, foot pain management, and proper footwear play important roles in fall prevention.
Distribution of Breath Sound Images in Patients with Pneumothoraces Compared to Healthy Subjects
Authors: Blanco Montserrat , Mor Ram , Fraticelli Anne , Breen David P. , Dutau Hervé
Published: December 2008

Background: Vibration response imaging (VRI) is a new technology that provides a radiation-free dynamic lung image from the vibrations produced by airflow. The vibration energy from the respiratory cycle can be quantified for any lung region. This is obtained by integrating the energy profiles from 42 acoustic sensors placed on the patient’s back. Objective: The aim of this study was to evaluate whether a physician trained in interpreting acoustic images can accurately distinguish between normal and abnormal breath sound distribution in patients with pneumothoraces compared to healthy controls. Methods: In total, 14 patients with spontaneous or iatrogenic pneumothoraces and 15 healthy volunteers were enrolled in the study. VRI recordings and physical examination were obtained in all cases. Chest radiographs (CXRs) were reviewed in patients with pneumothoraces. Dynamic images recorded during one complete respiratory cycle were analyzed for each subject. Results: The VRI images of patients with pneumothoraces demonstrated a reduction in the vibration response on the affected side which correlated with the CXR. Sensitivity was 100%, specificity was 87% and positive predictive value and negative predictive value were 86 and 100%, respectively. Conclusions: This study demonstrates that VRI can be safely used to assess patients with pneumothoraces. Moreover, the analysis of breath sound distribution images obtained noninvasively can distinguish between patients with a normal chest examination from those with pneumothoraces.
Coping Strategies and Social Participation in Older Adults
Authors: Demers Louise , Robichaud Line , Gélinas Isabelle , Noreau Luc , Desrosiers Johanne
Published: December 2008

Background: Social participation refers to daily activities, such as personal care and mobility, and social roles, such as interpersonal relationships and leisure. Although restrictions in participation in normal aging have been recognized, little research has been done to study the coping strategies used to alleviate those restrictions. Objective: The objective of the present study was to explore the relationships between cognitive and behavioural coping strategies and the social participation of community-dwelling older adults. Methods: The Assessment of Life Habits (LIFE-H) and the Inventory of Coping Strategies Used by the Elderly (ICSUE) were used to document social participation and coping strategies of 350 randomly recruited older adults living at home independently. Sociodemographic and health-related characteristics were also assessed. Regression analyses were performed to evaluate the relationship between social participation, coping strategies and the other variables. Results: Behavioural coping strategies were the most important factor associated with daily activities, social roles and total participation, followed by the type of living environment and age. These variables explained 33% (p = 0.04), 13% (p = 0.02), and 28% (p = 0.00) of the variance of the models, respectively. The absence of any relationship between the cognitive coping strategies and social participation was a striking result. Conclusion: Our study suggests expanding current geriatric approaches to integrate knowledge on useful, safe and appropriate behavioural changes and to help older people acquire such strategies when they are lacking.
Malignant Perinatal Variant of Long-QT Syndrome Caused by a Profoundly Dysfunctional Cardiac Sodium Channel
Authors: Wang Dao W. , Crotti Lia , Shimizu Wataru , Pedrazzini Matteo , Cantu Francesco , De Filippo Paolo , Kishiki Kanako , Miyazaki Aya , Ikeda Tomoaki , Schwartz Peter J. , George Alfred L.
Published: December 2008

Background—Inherited cardiac arrhythmia susceptibility contributes to sudden death during infancy and may contribute to perinatal and neonatal mortality, but the molecular basis of this risk and the relationship to genetic disorders presenting later in life is unclear. We studied the functional and pharmacological properties of a novel de novo cardiac sodium channel gene (SCN5A) mutation associated with an extremely severe perinatal presentation of long-QT syndrome in unrelated probands of different ethnicity.

Methods and Results—Two subjects exhibiting severe fetal and perinatal ventricular arrhythmias were screened forSCN5Amutations, and the functional properties of a novel missense mutation (G1631D) were determined by whole-cell patch clamp recording. In vitro electrophysiological studies revealed a profound defect in sodium channel function characterized by ≈10-fold slowing of inactivation, increased persistent current, slowing of recovery from inactivation, and depolarized voltage dependence of activation and inactivation. Single-channel recordings demonstrated increased frequency of late openings, prolonged mean open time, and increased latency to first opening for the mutant. Subjects carrying this mutation responded clinically to the combination of mexiletine with propranolol and survived. Pharmacologically, the mutant exhibited 2-fold greater tonic and use-dependent mexiletine block than wild-type channels. The mutant also exhibited enhanced tonic (2.4-fold) and use-dependent block (≈5-fold) by propranolol, and we observed additive effects of the 2 drugs on the mutant.

Conclusions—Our study demonstrates the molecular basis for a malignant perinatal presentation of long-QT syndrome, illustrates novel functional and pharmacological properties ofSCN5A-G1631D, which caused the disorder, and reveals therapeutic benefits of propranolol block of mutant sodium channels in this setting.
Incidence of Atrial Fibrillation in Relation to Changing Heart Rate Over Time in Hypertensive Patients
Authors: Okin Peter M. , Wachtell Kristian , Kjeldsen Sverre E. , Julius Stevo , Lindholm Lars H. , Dahlöf Björn , Hille Darcy A. , Nieminen Markku S. , Edelman Jonathan M. , Devereux Richard B.
Published: December 2008

Background—

Onset of atrial fibrillation (AF) has been linked to changes in autonomic tone, with increasing heart rate (HR) immediately before AF onset in some patients suggesting a possible role of acute increases in sympathetic activity in AF onset. Although losartan therapy and decreasing ECG left ventricular hypertrophy are associated with decreased AF incidence, the relationship of HR changes over time to development of AF has not been examined.

Methods and Results—

HR was evaluated in 8828 hypertensive patients without AF by history or on baseline ECG in the Losartan Intervention for End Point Reduction in Hypertension (LIFE) study. Patients were treated with losartan- or atenolol-based regimens and followed with serial ECGs annually which were used to determine HR and ECG left ventricular hypertrophy by Cornell product and Sokolow-Lyon voltage criteria. During mean follow-up of 4.7�1.1 years, new-onset AF occurred in 701 patients (7.9%). Patients with new AF had smaller decreases in HR to last in-treatment ECG or last ECG before AF (−2.7�13.5 versus −5.2�12.5 bpm), whether on losartan- (−0.4�13.5 versus −2.2�11.7 bpm) or atenolol-based treatment (−5.3�12.8 versus −8.3�12.6 bpm, all
P
<0.001). In univariate Cox analyses, higher HR on in-treatment ECGs was associated with an increased risk of new-onset AF, with a 15% greater risk of AF for every 10 bpm higher HR (95% CI 8% to 22%). In alternative analyses, persistence or development of a HR≥84 (upper quintile of baseline HR) was associated with a 46% greater risk of developing AF (95% CI 19% to 80%). After adjusting for treatment with losartan versus atenolol, baseline risk factors for AF, baseline and in-treatment systolic and diastolic pressure and the known predictive value of baseline and in-treatment ECG left ventricular hypertrophy for new AF, higher in-treatment HR remained strongly associated with new AF with a 19% higher risk for every 10 bpm higher HR (95% CI 10% to 28%) or a 61% increased rate of AF in patients with persistence or development of a HR≥84 (95% CI 27% to 104%, all
P
<0.001).

Conclusion—

Higher in-treatment HR on serial ECGs is associated with an increased likelihood of new-onset AF, independent of treatment modality, blood pressure lowering, and regression of ECG left ventricular hypertrophy in patients with essential hypertension.
ECG Quantification of Myocardial Scar in Cardiomyopathy Patients With or Without Conduction Defects
Authors: Strauss David G. , Selvester Ronald H. , Lima João A.C. , Arheden Håkan , Miller Julie M. , Gerstenblith Gary , Marbán Eduardo , Weiss Robert G. , Tomaselli Gordon F. , Wagner Galen S. , Wu Katherine C.
Published: December 2008

Background—

Myocardial scarring from infarction or nonischemic fibrosis forms an arrhythmogenic substrate. The Selvester QRS score has been extensively validated for estimating myocardial infarction scar size in the absence of ECG confounders, but has not been tested to quantify scar in patients with hypertrophy, bundle branch/fascicular blocks, or nonischemic cardiomyopathy. We assessed the hypotheses that (1) QRS scores (modified for each ECG confounder) correctly identify and quantify scar in ischemic and nonischemic patients when compared with the reference standard of cardiac magnetic resonance using late-gadolinium enhancement, and (2) QRS-estimated scar size predicts inducible sustained monomorphic ventricular tachycardia during electrophysiological testing.

Methods and Results—

One hundred sixty-two patients with left ventricular ejection fraction ≤35% (95 ischemic, 67 nonischemic) received 12-lead ECG and cardiac magnetic resonance using late-gadolinium enhancement before implantable cardioverter defibrillator placement for primary prevention of sudden cardiac death. QRS scores correctly diagnosed cardiovascular magnetic resonance scar presence with receiver operating characteristics area under the curve of 0.91 and correlation for scar quantification of
r
=0.74 (
P
<0.0001) for all patients. Performance within hypertrophy, conduction defect, and nonischemic subgroups ranged from area under the curve of 0.81 to 0.94 and
r
=0.60 to 0.80 (
P
<0.001 for all). Among the 137 patients undergoing electrophysiological or device testing, each 3-point QRS-score increase (9% left ventricular scarring) was associated with an odds ratio for inducing monomorphic ventricular tachycardia of 2.2 (95% CI, 1.5 to 3.2;
P
<0.001) for all patients, 1.7 (1.0 to 2.7,
P
=0.04) for ischemics, and 2.2 (1.0 to 5.0,
P
=0.05) for nonischemics.

Conclusions—

QRS scores identify and quantify scar in ischemic and nonischemic cardiomyopathy patients despite ECG confounders. Higher QRS-estimated scar size is associated with increased arrhythmogenesis and warrants further study as a risk-stratifying tool.
Multitask Visual Learning Using Genetic Programming
Authors: Jaśkowski Wojciech , Krawiec Krzysztof , Wieloch Bartosz
Published: December 2008

We propose a multitask learning method of visual concepts within the genetic programming (GP) framework. Each GP individual is composed of several trees that process visual primitives derived from input images. Two trees solve two different visual tasks and are allowed to share knowledge with each other by commonly calling the remaining GP trees (subfunctions) included in the same individual. The performance of a particular tree is measured by its ability to reproduce the shapes contained in the training images. We apply this method to visual learning tasks of recognizing simple shapes and compare it to a reference method. The experimental verification demonstrates that such multitask learning often leads to performance improvements in one or both solved tasks, without extra computational effort.
On the Choice of the Parent Population Size
Authors: Storch Tobias
Published: December 2008

Evolutionary algorithms (EAs) are population-based randomized search heuristics that often solve problems successfully. Here the focus is on the possible effects of changing the parent population size in a simple, but still realistic, mutation-based EA. It preserves diversity by avoiding duplicates in its population. On the one hand its behavior on well-known pseudo-Boolean example functions is investigated by means of a rigorous runtime analysis. A comparison with the expected runtime of the algorithm's variant that does not avoid duplicates demonstrates the strengths and weaknesses of maintaining diversity. On the other hand, newly developed functions are presented for which the optimizer considered that even a decrease of the population size by a single increment leads from efficient optimization to enormous runtime and overwhelming probability. This is proven for all feasible population sizes and thereby this result forms a hierarchy theorem. In order to obtain all these results new methods for the analysis of the EA are developed.
Seasonal Cycle–El Niño Relationship: Validation of Hypotheses
Authors: Xiao Heng , Mechoso Carlos R.
Published: December 2008

The present paper examines ways in which the seasonal cycle influences the evolution of El Niño in the tropical Pacific. The following hypotheses and associated physical mechanisms are investigated: (i) Hypothesis 1 (H1)—the seasonal warming of the cold tongue early in the calendar year (January–April) favors the initial growth of an event; (ii) hypothesis 2 (H2)—during an event, the warm surface waters migrating in the western basin from the Southern to the Northern Hemisphere during the northern spring (April–May) trigger enhanced convection along the equator, which contributes to reinforce the event; and (iii) hypothesis 3 (H3)—the warm surface waters returning in the western basin from the Northern to the Southern Hemisphere toward the end of the calendar year (November–January) favor the demise of ongoing events.

Hypothesis-validation experiments are performed with a coupled atmosphere–ocean general circulation model (CGCM)—the tropical Pacific version of the University of California, Los Angeles (UCLA) CGCM. The anomaly-coupling technique is applied, in which the simulated seasonal cycle and interannual variability can be separated and artificially modified to highlight the aspect targeted for examination, thus allowing for comparisons of simulations in which seasonal conditions in the CGCM’s atmospheric component are either fixed or time varying. The results obtained in the experiments are supportive of hypotheses H1 and H3. No supportive evidence is found for the validity of hypothesis H2.
Longitudinally Dependent Ozone Increase in the Antarctic Polar Vortex Revealed by Balloon and Satellite Observations
Authors: Sato K. , Tomikawa Y. , Hashida G. , Yamanouchi T. , Nakajima H. , Sugita T.
Published: December 2008

The horizontal structure of processes causing increases in ozone in the Antarctic polar vortex was examined using data measured in 2003 from an ozonesonde observation campaign at Syowa Station (39.6°E, 69.0°S) and from the Improved Limb Atmospheric Spectrometer II (ILAS-II) onboard the Advanced Earth Observing Satellite II. The ILAS-II data are daily and distributed uniformly at 14 points in the zonal direction, mostly at polar latitudes. The Antarctic ozone hole that developed in 2003 was one of the largest recorded. The period of focus in this study is 26 September through 24 October, when a strong polar vortex was situated in the stratosphere. An ozone mixing ratio contour (1.0 ppmv) moved downward near a height of 20 km during the period of focus. This increase in ozone is likely to result from downward transport of ozone-rich air originating from lower latitudes by Brewer–Dobson circulation. First, the descent rate of the mixing ratio contour was estimated by taking the geometric height as the vertical coordinate for the deep vortex interior around 20 km. A significant longitudinal dependence was observed. An analysis using ECMWF operational data shows that this dependence can be approximately explained by longitudinally dependent vertical movements of the isentropes caused by a zonal wavenumber-1 quasi-stationary planetary wave with amplitude and phases varying on a seasonal time scale. Next, the descent rate was calculated around 500 K (around 20 km) by taking the potential temperature (isentrope) as the vertical coordinate. The longitudinal dependence was still present using this coordinate, meaning that the ozone mixing ratio and its increase are not constant on the isentropic layer even in the interior of the polar vortex. A backward trajectory analysis showed that air parcels with large ozone mixing ratios were mostly transported from the polar vortex boundary region. This result suggests that lateral transport/mixing is important even before the breakup of the polar vortex. Results from a tracer–tracer correlation analysis of O3 and long-lived constituent N2O were also consistent with this inference. The contribution of lateral mixing to the increase in ozone was estimated at about 17% ± 4% that of the Brewer–Dobson circulation around 20 km, using the calculated descent rates. The results of this study also imply that Lagrangian downward motions in the vortex interior are not correctly estimated without accounting for lateral mixing, even if the polar vortex is dynamically stable.
Freshwater Discharge, Sediment Transport, and Modeled Climate Impacts of the Final Drainage of Glacial Lake Agassiz
Authors: Clarke Garry K. C. , Bush Andrew B. G. , Bush John W. M.
Published: December 2008

A cold event at around 8200 calendar years BP and the release, at around that time, of a huge freshwater outburst from ice-dammed glacial Lake Agassiz have lent support to the idea that the flood triggered the cold event. Some suggest that the freshwater addition caused a weakening of the North Atlantic meridional overturning circulation (MOC) thereby reducing the ocean transport of heat to high northern latitudes. Although several modeling efforts lend strength to this claim, the paleoceanographic record is equivocal. The authors’ aim is to use a coupled ocean–atmosphere model to examine the possibility that the two events are causally linked but that MOC reduction was not the main agent of change. It is found that the outburst flood and associated redirection of postflood meltwater drainage to the Labrador Sea, via Hudson Strait, can freshen the North Atlantic, leading to reduced salinity and sea surface temperature, and thus to increased sea ice production at high latitudes. The results point to the possibility that the preflood outflow to the St. Lawrence was extremely turbid and sufficiently dense to become hyperpycnal, whereas the postflood outflow through Hudson Strait had a lower load of suspended sediment and was buoyant.
Tropical and Extratropical Responses of the North Atlantic Atmospheric Circulation to a Sustained Weakening of the MOC
Authors: Brayshaw David J. , Woollings Tim , Vellinga Michael
Published: December 2008

The tropospheric response to a forced shutdown of the North Atlantic Ocean’s meridional overturning circulation (MOC) is investigated in a coupled ocean–atmosphere GCM [the third climate configuration of the Met Office Unified Model (HadCM3)]. The strength of the boreal winter North Atlantic storm track is significantly increased and penetrates much farther into western Europe. The changes in the storm track are shown to be consistent with the changes in near-surface baroclinicity, which can be linked to changes in surface temperature gradients near regions of sea ice formation and in the open ocean. Changes in the SST of the tropical Atlantic are linked to a strengthening of the subtropical jet to the north, which, combined with the enhanced storm track, leads to a pronounced split in the jet structure over Europe. EOF analysis and stationary box indices methods are used to analyze changes to the North Atlantic Oscillation (NAO). There is no consistent signal of a change in the variability of the NAO, and while the changes in the mean flow project onto the positive NAO phase, they are significantly different from it. However, there is a clear eastward shift of the NAO pattern in the shutdown run, and this potentially has implications for ocean circulation and for the interpretation of proxy paleoclimate records.