bluuebunny/crossref_metadata_2025 huggingface dataset:
Balance in Relation to Walking Deterioration in Adults With Spastic Bilateral Cerebral Palsy
Authors: Opheim Arve , Jahnsen Reidun , Olsson Elisabeth , Stanghelle Johan Kvalvik
Published: October 2011

Background

Balance function is central in walking, and impaired balance function may be related to walking deterioration in adults with spastic bilateral cerebral palsy (CP).

Objectives

The purposes of this study were: (1) to compare balance confidence, fear of falling, and balance ability in adults with spastic bilateral CP, with and without self-reported walking deterioration; (2) to characterize balance confidence, fear of falling, and balance ability across all participants; and (3) to examine the relationship between balance confidence and balance ability across all participants.

Design

A case-control design was used.

Methods

Sixteen adults from a 7-year follow-up study who had spastic bilateral CP and were under 40 years of age in the 2006 survey participated. Eight participants reported walking deterioration (cases), and 8 participants did not report walking deterioration (controls). Outcome variables were: the Activities-specific Balance Confidence (ABC) Scale, the Falls Efficacy Scale–International (FES-I), and the Balance Evaluation Systems Test (BESTest).

Results

No differences in any of the outcome variables were found between the cases and the controls. Across all participants, the ABC Scale and FES-I scores were 62% and 24 points, respectively. Reduced ABC Scale scores and increased FES-I scores were found when using escalators, walking in crowds, and walking on slippery surfaces. The BESTest subscale scores were 60% to 79% of the maximum score, but only 31% and 42% of the maximum score in postural responses and anticipatory adjustments, respectively. Balance confidence correlated positively with postural responses, sensory orientation, stability in gait, and BESTest total score.

Limitations

The lack of reliability and validity tests for the outcome variables in this study population and the small number of participants were limitations of the study.

Conclusions

Self-reported walking deterioration in this group could not be explained by differences in balance confidence, fear of falling, or balance ability. Across all participants, most balance problems seemed related to reduced postural responses and anticipatory adjustments.
Kenneth Grant Jamieson (1925–1976): his life and contributions to neurosurgery
Authors: Mortazavi Martin , Deep Aman , Tubbs R. Shane , Fisher Wink S.
Published: October 2011

Manuscript submitted May 23, 2011. Accepted September 25, 2011. Kenneth Grant Jamieson is celebrated as one of Australia's top neurosurgeons. His most notable contributions to neurosurgery included novel treatments of aneurysms and pineal tumors and studies of head injury. Jamieson was also an innovator for the development of new neurosurgical instruments and renowned for his teaching abilities, prolificacy, and mentorship. This preeminent neurosurgeon's life was cut short at the age of 51. Our current understanding and knowledge of treatments of various neurosurgical diseases is based on pioneers such as Kenneth Grant Jamieson.
Mapping the Moment: a spatio-temporal interface for studying performance culture, Nottingham, 1857–1867
Authors: Robinson Jo , Priestnall Gary , Tyler-Jones Richard , Burgess Robin
Published: October 2011

The Mapping the Moment: Performance Culture in Nottingham, 1857–67 project ( http://www.nottingham.ac.uk/mapmoment ) is an interdisciplinary collaboration between performance history and geography, which has as its aim the investigation of the complex connections between the different kinds and sites of entertainment, and between the people and communities involved in making and watching performance, in what was then the rapidly developing East Midlands town of mid-Victorian Nottingham. As questions of space, proximity and temporal relationships are central to the choice-making processes of both venue managers and potential spectators, so we sought to create a resource, based on a map of nineteenth-century Nottingham, that organised information about the town and its performance culture in ways that highlighted such connections and allowed us to explore the relationships between place, performance and audience within the town. Here we describe the creation of the resource and reflect on the development of our spatio-temporal mapping approach, arguing that this offers the potential to address patterns of connectivity and change across both time and space, not as a series of disconnected cross sections but rather as representative of the ‘world of process’ in which the events we study actually take place.
Old habits, new dynamics: a case study of Web 2.0 in collaborative humanities and arts research
Authors: Goren Dan
Published: October 2011

Whilst the application of online multimedia digital technology within arts and humanities research has burgeoned over the last decade, the practice of openly conducting collaborative and in particular discursive research publicly online remains one of the most unfamiliar and conceptually problematic areas for many academics in the field. Based on user surveys, blog posts, and forum discussions, this article provides both an account and assessment of Web 2.0 technologies in use on a large-scale arts and humanities research project. Examining usage by and impressions of both the project team and the wider community of users, it investigates both the advantages gained and problems faced through the use of a virtual research environment (VRE). It also pays special attention to the use of video and its implications for research practices.
The assimilation and use of GIS by historians: a sociotechnical interaction networks (STIN) analysis
Authors: Suri Venkata Ratnadeep
Published: October 2011

One strategic way to understand the impact of digital technologies on a domain of research is to identify how these technologies factor into scholars’ realm of everyday academic practice. I present an evaluative strategy grounded in the field of social informatics referred to as socio-technical interaction networks (STIN) approach. The central tenet of this analytical approach is that it models the context of humanities scholars’ routine engagement with digital technologies as a sociotechnical network-a web of relationships of technological and social elements. Using qualitative data collected from multiple sources I demonstrate the value of STIN as an analytical approach by analysing the assimilation and use of Geographical Information systems (GIS) by researchers studying historical topics. I conclude by identifying some of the core issues emerging from this study and how these issues can be useful to think about policy and strategy aspects related to digital humanities.
Dysfunctional Incidental Olfaction in Mild Cognitive Impairment (MCI): An Electroencephalography (EEG) Study
Authors: Walla Peter , Duregger Cornelia , Deecke Lüder , Dal-Bianco Peter
Published: October 2011

Our study provides evidence that Mild Cognitive Impairment (MCI) is associated with olfactory dysfunction on both conscious and non-conscious levels. MCI patients and age-matched controls underwent a face processing task during which sympathy decisions had to be made via button presses. Incidentally, some of the faces were associated with a simultaneously presented odour. Although attention was paid to faces, brain activities were analysed with respect to odour versus no-odour conditions. Behavioural differences were found related to overall face recognition performance, but these were not statistically significant. However, odour-related neurophysiology differed between both groups. Normal controls demonstrated brain activity differences between odour and no-odour conditions that resemble difference activity patterns in healthy young participants as described in a previous magnetoencephalography (MEG) study [1]. They showed odour-related activity patterns between about 160 ms and 320 ms after stimulus onset and between about 640 ms and 720 ms. On the other hand, the patient group did not show any such difference activities. Based on previous research we interpret the early odour-related brain activity pattern in controls as being associated with subliminal olfaction and the later activity pattern with conscious olfaction. None of these were found in MCI patients, although it has to be emphasised that our sample size was rather small. We confirm previous findings about olfactory related dysfunction in patients with MCI and conclude from our findings that even subliminal odour-related information processing is impaired.
A Review of the Role of Re-Irradiation in Recurrent High-Grade Glioma (HGG)
Authors: Amichetti Maurizio , Amelio Dante
Published: October 2011

Despite the use of more effective multimodal treatments in high-grade glioma (HGG), the outcome of patients affected by this disease is still dismal and recurrence is a very common event. Many therapeutic approaches, alone or combined (surgery, drugs, targeted agents, immunotherapy, radiotherapy, supportive therapy), are available in the clinical armamentarium so far. The attitude of physicians is increasingly interventionist, but recurrent HGG still remains a very difficult scenario to be treated. Radiotherapy with different re-irradiation techniques is increasingly proposed as a therapeutic option with interesting results, even though the resulting duration of response is usually quite short. Most lesions re-recur locally, with inadequate identification and targeting of viable tumor being the most important cause of failure. Prognosis is affected by many patient-, tumor-, and treatment-associated prognostic factors. Radiotherapy is delivered with many advanced modalities: 3D-CRT, intensity-modulated radiation therapy, stereotactic fractionated radiotherapy, radiosurgery, and brachitherapy with or without chemotherapy administration. In order to evaluate the feasibility and efficacy of re-irradiation in this setting, we reviewed the PubMed and MEDLINE databases restricting the search to original reports published from January 1990 to June 2011. The search resulted in a total of 155 reports: 78 of them covering 2,688 patients treated with different irradiation modalities overall fulfilled the entry criteria. Radiation therapy demonstrated to be an acceptable option in recurrent HGG with good response rates and acceptable toxicity.
Genetic Diversity in Jatropha curcas Populations in the State of Chiapas, Mexico
Authors: Ovando-Medina Isidro , Sánchez-Gutiérrez Adriana , Adriano-Anaya Lourdes , Espinosa-García Francisco , Núñez-Farfán Juan , Salvador-Figueroa Miguel
Published: October 2011

Jatropha curcas L. has become an important source of oil production for biodiesel fuel. Most genetic studies of this plant have been conducted with Asian and African accessions, where low diversity was encountered. There are no studies of this kind focusing in the postulated region of origin. Therefore, five populations of J. curcas were studied in the state of Chiapas, Mexico, using amplified fragment length polymorphism (AFLP) markers. One hundred and fifty-two useful markers were obtained: overall polymorphism = 81.18% and overall Nei’s genetic diversity (He) = 0.192. The most diverse population was the Border population [He: 0.245, Shanon’s information index (I): 0.378]. A cluster analysis revealed the highest dissimilarity coefficient (0.893) yet to be reported among accessions. An analysis of molecular variance (AMOVA) revealed that the greatest variation is within populations (87.8%), followed by the variation among populations (7.88%). The PhiST value (0.121) indicated moderate differentiation between populations. However, a spatial AMOVA (SAMOVA) detected a stronger genetic structure of populations, with a PhiST value of 0.176. To understand the fine structure of populations, an analysis of data with Bayesian statistics was conducted with software Structure©. The number of genetic populations (K) was five, with mixed ancestry in most individuals (genetic migrants), except in the Soconusco, where there was a tiny fraction of fragments from other populations. In contrast, SAMOVA grouped populations in four units. To corroborate the above findings, we searched for possible genetic barriers, determining as the main barrier that separating the Border from the rest of the populations. The results are discussed based on the possible ancestry of populations.
The Evolution of Protein Structures and Structural Ensembles Under Functional Constraint
Authors: Siltberg-Liberles Jessica , Grahnen Johan A. , Liberles David A.
Published: October 2011

Protein sequence, structure, and function are inherently linked through evolution and population genetics. Our knowledge of protein structure comes from solved structures in the Protein Data Bank (PDB), our knowledge of sequence through sequences found in the NCBI sequence databases (http://www.ncbi.nlm.nih.gov/), and our knowledge of function through a limited set of in-vitro biochemical studies. How these intersect through evolution is described in the first part of the review. In the second part, our understanding of a series of questions is addressed. This includes how sequences evolve within structures, how evolutionary processes enable structural transitions, how the folding process can change through evolution and what the fitness impacts of this might be. Moving beyond static structures, the evolution of protein kinetics (including normal modes) is discussed, as is the evolution of conformational ensembles and structurally disordered proteins. This ties back to a question of the role of neostructuralization and how it relates to selection on sequences for functions. The relationship between metastability, the fitness landscape, sequence divergence, and organismal effective population size is explored. Lastly, a brief discussion of modeling the evolution of sequences of ordered and disordered proteins is entertained.
Identification of Genes Involved in the Glycosylation of Modified Viosamine of Flagellins in Pseudomonas syringae by Mass Spectrometry
Authors: Yamamoto Masanobu , Ohnishi-Kameyama Mayumi , Nguyen Chi L. , Taguchi Fumiko , Chiku Kazuhiro , Ishii Tadashi , Ono Hiroshi , Yoshida Mitsuru , Ichinose Yuki
Published: October 2011

Previously we revealed that flagellin proteins in Pseudomonas syringae pv. tabaci 6605 (Pta 6605) were glycosylated with a trisaccharide, modified viosamine (mVio)-rhamnose-rhamnose and that glycosylation was required for virulence. We further identified some glycosylation-related genes, including vioA, vioB, vioT, fgt1, and fgt2. In this study, we newly identified vioR and vioM in a so-called viosamine island as biosynthetic genes for glycosylation of mVio in Pta 6605 by the mass spectrometry (MS) of flagellin glycan in the respective mutants. Furthermore, characterization of the mVio-related genes and MS analyses of flagellin glycans in other pathovars of P. syringae revealed that mVio-related genes were essential for mVio biosynthesis in flagellin glycans, and that P. syringae pv. syringae B728a, which does not possess a viosamine island, has a different structure of glycan in its flagellin protein.
Microsatellite Analysis in Multistage Carcinogenesis of Esophageal Squamous Cell Carcinoma from Chongqing in Southern China
Authors: Liu Ming , Zhang Feng , Liu Shen , Zhao Wen , Zhu Jing , Zhang Xiaoli
Published: October 2011

In order to characterize the molecular events in the carcinogenesis of esophageal cancer and to identify biomarkers for the early detection of the disease, matched precancerous and cancerous tissues resected from 34 esophageal cancer patients in Chongqing of southern China were compared for the extent of loss of heterozygosity (LOH). Sixteen microsatellite markers on nine chromosome regions were used for the PCR-based LOH analysis. The overall frequency of LOH at the 16 microsatellite loci was significantly increased as the pathological status of the resection specimens changed from low-grade dysplasia (LGD) to high-grade dysplasia (HGD) and squamous cell carcinoma (SCC) (P < 0.001), indicating that tumorigenesis of the esophageal squamous epithelia is a progressive process involving accumulative changes of LOH. A total of eight markers showed LOH in the LGD samples, suggesting that these loci may be involved in the early-stage tumorigenesis of esophageal squamous cell carcinoma (ESCC) and that LOH analysis at these loci may help improve the early detection of this disease. In addition, heterozygosity was regained at four loci in the SCC samples of four patients compared with the HGD samples, suggesting the possibility of genetic heterogeneity in the tumorigenesis of esophageal cancer.
A Sandwich Electrochemical Immunosensor Using Magnetic DNA Nanoprobes for Carcinoembryonic Antigen
Authors: Gan Ning , Jia Liyong , Zheng Lei
Published: October 2011

A novel magnetic nanoparticle-based electrochemical immunoassay of carcinoembryonic antigen (CEA) was designed as a model using CEA antibody-functionalized magnetic beads [DNA/Fe3O4/ZrO2; Fe3O4 (core)/ZrO2 (shell) nano particles (ZMPs)] as immunosensing probes. To design the immunoassay, the CEA antibody and O-phenylenediamine (OPD) were initially immobilized on a chitosan/nano gold composite membrane on a glassy carbon electrode (GCE/CS-nano Au), which was used for CEA recognition. Then, horseradish peroxidase (HRP)-labeled anti-CEA antibodies (HRP-CEA Ab2) were bound to the surface of the synthesized magnetic ZMP nanoparticles as signal tag. Thus, the sandwich-type immune complex could be formed between secondary antibody (Ab2) modified DNA/ZMPs nanochains tagged by HRP and GCE/CS-nano Au. Unlike conventional nanoparticle-based electrochemical immunoassays, the recognition elements of this immunoassay included both electron mediators and enzyme labels, which obviously simplifies the electrochemical measurement process. The sandwich-type immunoassay format was used for online formation of the immunocomplex of CEA captured in the detection cell with an external magnet. The electrochemical signals derived from HRP during the reduction of H2O2 with OPD as electron mediator were measured. The method displayed a high sensitivity for CEA detection in the range of 0.008–200 ng/mL, with a detection limit of 5 pg/mL (estimated at a signal-to-noise ratio of 3). The precision, reproducibility, and stability of the immunoassay were good. The use of the assay was evaluated with clinical serum samples, and the results were in excellent accordance with those obtained using the standard enzyme-linked immunosorbent assay (ELISA) method. Thus, the magnetic nanoparticle-based assay format is a promising approach for clinical applications, and it could be further developed for the detection of other biomarkers in cancer diagnosis.
Distribution and Clinical Significance of Th17 Cells in the Tumor Microenvironment and Peripheral Blood of Pancreatic Cancer Patients
Authors: He Songbing , Fei Min , Wu Yugang , Zheng Dingcheng , Wan Daiwei , Wang Liang , Li Dechun
Published: October 2011

This study was designed to investigate the distribution of Th17 cells in the tumor microenvironment and peripheral blood of pancreatic cancer patients, its clinical significance, and the expression profile of Th17 cell-associated cytokines. The percentage of Th17 cells detected by flow cytometry analysis (FACS) was significantly higher in 46 pancreatic tumor tissues (5.28 ± 1.65%) compared with corresponding adjacent normal tissues (2.57 ± 0.83%) (P = 0.031). In addition, the percentage of Th17 cells was significantly higher in stage III-IV tumors than stage I-II tumors (P = 0.039). The percentage of Th17 cells in peripheral blood of 20 pancreatic cancer patients (3.99 ± 1.15%) was significantly higher than 15 healthy volunteers (1.98 ± 0.57%) (P = 0.027). Immunohistochemistry (IHC) was performed to detect IL-17+ cells in 46 pancreatic tumor tissues, as well as expression of CD34 in 24 tumor tissues. IL-17 was shown to mainly locate in cytoplasm, and the frequency of IL-17+ cells in tumor tissues (39/46) was higher than control (29/46). The presence of IL-17+ cells in tumor tissues was associated with tumor, node, and metastasis (TNM) stage, and lymph node metastasis (P = 0.012 and P = 0.009) but not with patient sex, age, tumor size, and histological grade (P > 0.05). Interestingly, distribution of Th17 cells in tumor tissues was positively correlated with microvessel density (MVD) (r = 0.86, P = 0.018). Furthermore, the median survival time of patients with high and low level of IL-17+ cells frequency was 14.5 and 18.5 months respectively (P = 0.023). The serum levels of Th17 cell-associated cytokines, IL-17 and IL-23 in 20 pancreatic patients detected by enzyme-linked immunosorbent assay (ELISA) were 69.2 ± 28.5 pg/mL and 266.5 ± 98.1 pg/mL, respectively, which were significantly higher than 15 healthy volunteers (P = 0.015 and P = 0.02). Moreover, levels of IL-17 and IL-23 were significantly higher in stage III-IV tumors than stage I-II tumors (P = 0.04 and P = 0.036). This study suggests that increase in Th17 cells frequency and its related cytokines levels in pancreatic tumor tissues may indicate involvement in the invasion and metastasis of pancreatic cancer, which may thereby affect patient prognosis. Therefore, Th17 cells and related cytokines may be served as important immune indicators for predicting the prognosis of pancreatic cancer patients.
Novel Ionic Liquid with Both Lewis and Brønsted Acid Sites for Michael Addition
Authors: Jiang Xiaoyue , Ye Weidong , Song Xiaohua , Ma Wenxin , Lao Xuejun , Shen Runpu
Published: October 2011

Ionic liquid with both Lewis and Brønsted acid sites has been synthesized and its catalytic activities for Michael addition were carefully studied. The novel ionic liquid was stable to water and could be used in aqueous solution. The molar ratio of the Lewis and Brønsted acid sites could be adjusted to match different reactions. The results showed that the novel ionic liquid was very efficient for Michael addition with good to excellent yields within several min. Operational simplicity, high stability to water and air, small amount used, low cost of the catalyst used, high yields, chemoselectivity, applicability to large-scale reactions and reusability are the key features of this methodology, which indicated that this novel ionic liquid also holds great potential for environmentally friendly processes.
Approaches to Modeling of Recrystallization
Authors: Hallberg Håkan
Published: October 2011

Control of the material microstructure in terms of the grain size is a key component in tailoring material properties of metals and alloys and in creating functionally graded materials. To exert this control, reliable and efficient modeling and simulation of the recrystallization process whereby the grain size evolves is vital. The present contribution is a review paper, summarizing the current status of various approaches to modeling grain refinement due to recrystallization. The underlying mechanisms of recrystallization are briefly recollected and different simulation methods are discussed. Analytical and empirical models, continuum mechanical models and discrete methods as well as phase field, vertex and level set models of recrystallization will be considered. Such numerical methods have been reviewed previously, but with the present focus on recrystallization modeling and with a rapidly increasing amount of related publications, an updated review is called for. Advantages and disadvantages of the different methods are discussed in terms of applicability, underlying assumptions, physical relevance, implementation issues and computational efficiency.
Phytoceramide Shows Neuroprotection and Ameliorates Scopolamine-Induced Memory Impairment
Authors: Jung Jae-Chul , Lee Yeonju , Moon Sohyeon , Ryu Jong Hoon , Oh Seikwan
Published: October 2011

The function and the role phytoceramide (PCER) and phytosphingosine (PSO) in the central nervous system has not been well studied. This study was aimed at investigating the possible roles of PCER and PSO in glutamate-induced neurotoxicity in cultured neuronal cells and memory function in mice. Phytoceramide showed neuro-protective activity in the glutamate-induced toxicity in cultured cortical neuronal cells. Neither phytosphingosine nor tetraacetylphytosphingosine (TAPS) showed neuroproective effects in neuronal cells. PCER (50 mg/kg, p.o.) recovered the scopolamine-induced reduction in step-through latency in the passive avoidance test; however, PSO did not modulate memory function on this task. The ameliorating effects of PCER on spatial memory were confirmed by the Morris water maze test. In conclusion, through behavioral and neurochemical experimental results, it was demonstrated that central administration of PCER produces amelioration of memory impairment. These results suggest that PCER plays an important role in neuroprotection and memory enhancement and PCER could be a potential new therapeutic agent for the treatment of neurodegenerative diseases such as Alzheimer’s disease.
Estimating Crown Variables of Individual Trees Using Airborne and Terrestrial Laser Scanners
Authors: Jung Sung-Eun , Kwak Doo-Ahn , Park Taejin , Lee Woo-Kyun , Yoo Seongjin
Published: October 2011

In this study, individual tree height (TH), crown base height (CBH), crown area (CA) and crown volume (CV), which were considered as essential parameters for individual stem volume and biomass estimation, were estimated by both an airborne laser scanner (ALS) and a terrestrial laser scanner (TLS). These ALS- and TLS-derived tree parameters were compared because TLS has been introduced as an instrument to measure objects more precisely. ALS-estimated TH was extracted from the highest value within a crown boundary delineated with the crown height model (CHM). The ALS-derived CBH of individual trees was estimated by k-means clustering method using the ALS data within the boundary. The ALS-derived CA was calculated simply with the crown boundary, after which CV was computed automatically using the crown geometric volume (CGV). On the other hand, all TLS-derived parameters were detected manually and precisely except the TLS-derived CGV. As a result, the ALS-extracted TH, CA, and CGV values were underestimated whereas CBH was overestimated when compared with the TLS-derived parameters. The coefficients of determination (R2) from the regression analysis between the ALS and TLS estimations were approximately 0.94, 0.75, 0.69 and 0.58, and root mean square errors (RMSEs) were approximately 0.0184 m, 0.4929 m, 2.3216 m2 and 13.2087 m3 for TH, CBH, CA and CGV, respectively. Thereby, the error rate decreased to 0.0089, 0.0727 and 0.0875 for TH, CA and CGV via the combination of ALS and TLS data.
A Novel Combined SLAM Based on RBPF-SLAM and EIF-SLAM for Mobile System Sensing in a Large Scale Environment
Authors: He Bo , Zhang Shujing , Yan Tianhong , Zhang Tao , Liang Yan , Zhang Hongjin
Published: October 2011

Mobile autonomous systems are very important for marine scientific investigation and military applications. Many algorithms have been studied to deal with the computational efficiency problem required for large scale Simultaneous Localization and Mapping (SLAM) and its related accuracy and consistency. Among these methods, submap-based SLAM is a more effective one. By combining the strength of two popular mapping algorithms, the Rao-Blackwellised particle filter (RBPF) and extended information filter (EIF), this paper presents a Combined SLAM—an efficient submap-based solution to the SLAM problem in a large scale environment. RBPF-SLAM is used to produce local maps, which are periodically fused into an EIF-SLAM algorithm. RBPF-SLAM can avoid linearization of the robot model during operating and provide a robust data association, while EIF-SLAM can improve the whole computational speed, and avoid the tendency of RBPF-SLAM to be over-confident. In order to further improve the computational speed in a real time environment, a binary-tree-based decision-making strategy is introduced. Simulation experiments show that the proposed Combined SLAM algorithm significantly outperforms currently existing algorithms in terms of accuracy and consistency, as well as the computing efficiency. Finally, the Combined SLAM algorithm is experimentally validated in a real environment by using the Victoria Park dataset.
A Comprehensive Approach to WSN-Based ITS Applications: A Survey
Authors: Losilla Fernando , Garcia-Sanchez Antonio-Javier , Garcia-Sanchez Felipe , Garcia-Haro Joan , Haas Zygmunt J.
Published: October 2011

In order to perform sensing tasks, most current Intelligent Transportation Systems (ITS) rely on expensive sensors, which offer only limited functionality. A more recent trend consists of using Wireless Sensor Networks (WSN) for such purpose, which reduces the required investment and enables the development of new collaborative and intelligent applications that further contribute to improve both driving safety and traffic efficiency. This paper surveys the application of WSNs to such ITS scenarios, tackling the main issues that may arise when developing these systems. The paper is divided into sections which address different matters including vehicle detection and classification as well as the selection of appropriate communication protocols, network architecture, topology and some important design parameters. In addition, in line with the multiplicity of different technologies that take part in ITS, it does not consider WSNs just as stand-alone systems, but also as key components of heterogeneous systems cooperating along with other technologies employed in vehicular scenarios.
Improved Kalman Filter Method for Measurement Noise Reduction in Multi Sensor RFID Systems
Authors: Eom Ki Hwan , Lee Seung Joon , Kyung Yeo Sun , Lee Chang Won , Kim Min Chul , Jung Kyung Kwon
Published: October 2011

Recently, the range of available Radio Frequency Identification (RFID) tags has been widened to include smart RFID tags which can monitor their varying surroundings. One of the most important factors for better performance of smart RFID system is accurate measurement from various sensors. In the multi-sensing environment, some noisy signals are obtained because of the changing surroundings. We propose in this paper an improved Kalman filter method to reduce noise and obtain correct data. Performance of Kalman filter is determined by a measurement and system noise covariance which are usually called the R and Q variables in the Kalman filter algorithm. Choosing a correct R and Q variable is one of the most important design factors for better performance of the Kalman filter. For this reason, we proposed an improved Kalman filter to advance an ability of noise reduction of the Kalman filter. The measurement noise covariance was only considered because the system architecture is simple and can be adjusted by the neural network. With this method, more accurate data can be obtained with smart RFID tags. In a simulation the proposed improved Kalman filter has 40.1%, 60.4% and 87.5% less Mean Squared Error (MSE) than the conventional Kalman filter method for a temperature sensor, humidity sensor and oxygen sensor, respectively. The performance of the proposed method was also verified with some experiments.
Directed aromatic functionalization in natural-product synthesis: Fredericamycin A, nothapodytine B, and topopyrones B and D
Authors: Turner Charles Dylan , Ciufolini Marco A
Published: October 2011

This is a review of our efforts toward the synthesis of a group of natural products that display noteworthy biological activity: Fredericamycin A, nothapodytine B, and topopyrones B and D. In each case, directed aromatic functionalization methodology greatly facilitated the assembly of the key molecular subunits.
Using a Curved Kirschner Wire for Fixation of Unstable Distal Radius Fractures in Children
Authors: Misra Anand , Alcelik Ilhan , Sukeik Mohamed
Published: October 2011

Displaced metaphyseal and diaphyseal fractures of the distal radius are common in children [...]
The iconic significance of the Psalms as a literary genre for speaking about God: A phenomenological perspective
Authors: Veldsman Daniël P.
Published: October 2011

To explore the impossible impossibility of speaking about God and to address, on the one hand, the unacceptable modernistic rational robe of totalisation and the return of the subject in postmodern contexts, on the other, this article pursued the phenomenological approach of Jean-Luc Marion’s hermeneutic of the icon. His approach is connected in a creative manner to the literary ‘eyes’ of the Psalter, focusing on the distinction of idol–icon by Marion in his understanding of the gaze of the worshipper and the subsequent conceptualisation of the infinite God in finite human terms. It was finally argued that the literary genre of the Psalter, viewed from a hermeneutic of the icon, presents not only an exciting perspective on the threshold of the ‘[im-]possible’ for speaking about God, but also on the return of the subject in the broadened horizon of the ‘unsayable’ and ‘unrepresentable’.
A Modified Discontinuous Galerkin Method for Solving Efficiently Helmholtz Problems
Authors: Grigoroscuta-Strugaru Magdalena , Amara Mohamed , Calandra Henri , Djellouli Rabia
Published: October 2011

A new solution methodology is proposed for solving efficiently Helmholtz problems. The proposed method falls in the category of the discontinuous Galerkin methods. However, unlike the existing solution methodologies, this method requires solving (a) well-posed local problems to determine the primal variable, and (b) a global positive semi-definite Hermitian system to evaluate the Lagrange multiplier needed to restore the continuity across the element edges. Illustrative numerical results obtained for two-dimensional interior Helmholtz problems are presented to assess the accuracy and the stability of the proposed solution methodology.
Analysis of Convolution Quadrature Applied to the Time-Domain Electric Field Integral Equation
Authors: Chen Q. , Monk P. , Wang X. , Weile D.
Published: October 2011

We show how to apply convolution quadrature (CQ) to approximate the time domain electric field integral equation (EFIE) for electromagnetic scattering. By a suitable choice of CQ, we prove that the method is unconditionally stable and has the optimal order of convergence. Surprisingly, the resulting semi discrete EFIE is dispersive and dissipative, and we analyze this phenomena. Finally, we present numerical results supporting and extending our convergence analysis.
A Preconditioned Iterative Solver for the Scattering Solutions of the Schrödinger Equation
Authors: Zubair Hisham bin , Reps Bram , Vanroose Wim
Published: October 2011

The Schrödinger equation defines the dynamics of quantum particles which has been an area of unabated interest in physics. We demonstrate how simple transformations of the Schrödinger equation leads to a coupled linear system, whereby each diagonal block is a high frequency Helmholtz problem. Based on this model, we derive indefinite Helmholtz model problems with strongly varying wavenumbers. We employ the iterative approach for their solution. In particular, we develop a preconditioner that has its spectrum restricted to a quadrant (of the complex plane) thereby making it easily invertible by multigrid methods with standard components. This multigrid preconditioner is used in conjunction with suitable Krylov-subspace methods for solving the indefinite Helmholtz model problems. The aim of this study is to report the feasibility of this preconditioner for the model problems. We compare this idea with the other prevalent preconditioning ideas, and discuss its merits. Results of numerical experiments are presented, which complement the proposed ideas, and show that this preconditioner may be used in an automatic setting.
Matched Asymptotic Expansions of the Eigenvalues of a 3-D Boundary-Value Problem Relative to Two Cavities Linked by a Hole of Small Size
Authors: Bendali Abderrahmane , Fares M’Barek , Tizaoui Abdelkader , Tordeux Sébastien
Published: October 2011

In this article, we consider a domain consisting of two cavities linked by a hole of small size. We derive a numerical method to compute an approximation of the eigenvalues of an elliptic operator without refining in the neighborhood of the hole. Several convergence rates are obtained and illustrated by numerical simulations.
Multiscale Nanorod Metamaterials and Realizable Permittivity Tensors
Authors: Bouchitté G. , Bourel C.
Published: October 2011

Our aim is to evidence new 3D composite diffractive structures whose effective permittivity tensor can exhibit very large positive or negative real eigenvalues. We use a reiterated homogenization procedure in which the first step consists in considering a bounded obstacle made of periodically disposed parallel high conducting metallic fibers of finite length and very thin cross section. As shown in [2], the resulting constitutive law is non-local. Then by reproducing periodically the same kind of obstacle at small scale, we obtain a local effective law described by a permittivity tensor that we make explicit as a function of the frequency. Due to internal resonances, the eigenvalues of this tensor have real part that change of sign and are possibly very large within some range of frequencies. Numerical simulations are shown.
Simultaneous Scatterer Shape Estimation and Partial Aperture Far-Field Pattern Denoising
Authors: Olshansky Yaakov , Turkel Eli
Published: October 2011

We study the inverse problem of recovering the scatterer shape from the far-field pattern(FFP) in the presence of noise. Furthermore, only a discrete partial aperture is usually known. This problem is ill-posed and is frequently addressed using regularization. Instead, we propose to use a direct approach denoising the FFP using a filtering technique. The effectiveness of the technique is studied on a scatterer with the shape of the ellipse with a tower. The forward scattering problem is solved using the finite element method (FEM). The numerical FFP is additionally corrupted by Gaussian noise. The shape parameters are found based on a least-square error estimator. If ũ∞ is a perturbation of the FFP then we attempt to find Γ, the scatterer shape, which minimizes ∣∣ũ∞ − ũ∞∣∣ using the conjugate gradient method for the denoised FFP
Time-Harmonic Acoustic Scattering in a Complex Flow: A Full Coupling Between Acoustics and Hydrodynamics
Authors: Dhia A.S.Bonnet-Ben , Mercier J.F. , Millot F. , Pernet S. , Peynaud E.
Published: October 2011

For the numerical simulation of time harmonic acoustic scattering in a complex geometry, in presence of an arbitrary mean flow, the main difficulty is the coexistence and the coupling of two very different phenomena: acoustic propagation and convection of vortices. We consider a linearized formulation coupling an augmented Galbrun equation (for the perturbation of displacement) with a time harmonic convection equation (for the vortices). We first establish the well-posedness of this time harmonic convection equation in the appropriate mathematical framework. Then the complete problem, with Perfectly Matched Layers at the artificial boundaries, is proved to be coercive + compact, and a hybrid numerical method for the solution is proposed, coupling finite elements for the Galbrun equation and a Discontinuous Galerkin scheme for the convection equation. Finally a 2D numerical result shows the efficiency of the method.
Operator Factorization for Multiple-Scattering Problems and an Application to Periodic Media
Authors: Coatléven J. , Joly P.
Published: October 2011

This work concerns multiple-scattering problems for time-harmonic equations in a reference generic media. We consider scatterers that can be sources, obstacles or compact perturbations of the reference media. Our aim is to restrict the computational domain to small compact domains containing the scatterers. We use Robin-to-Robin (RtR) operators (in the most general case) to express boundary conditions for the interior problem. We show that one can always factorize the RtR map using only operators defined using single-scatterer problems. This factorization is based on a decomposition of the diffracted field, on the whole domain where it is defined. Assuming that there exists a good method for solving single-scatterer problems, it then gives a convenient way to compute RtR maps for a random number of scatterers.
A Preconditioned 3-D Multi-Region Fast Multipole Solver for Seismic Wave Propagation in Complex Geometries
Authors: Chaillat S. , Semblat J.F. , Bonnet M.
Published: October 2011

The analysis of seismic wave propagation and amplification in complex geological structures requires efficient numerical methods. In this article, following up on recent studies devoted to the formulation, implementation and evaluation of 3-D single- and multi-region elastodynamic fast multipole boundary element methods (FM-BEMs), a simple preconditioning strategy is proposed. Its efficiency is demonstrated on both the single- and multi-region versions using benchmark examples (scattering of plane waves by canyons and basins). Finally, the preconditioned FM-BEM is applied to the scattering of plane seismic waves in an actual configuration (alpine basin of Grenoble, France), for which the high velocity contrast is seen to significantly affect the overall efficiency of the multi-region FM-BEM.
A High Frequency Boundary Element Method for Scattering by Convex Polygons with Impedance Boundary Conditions
Authors: Chandler-Wilde S. N. , Langdon S. , Mokgolele M.
Published: October 2011

We consider scattering of a time harmonic incident plane wave by a convex polygon with piecewise constant impedance boundary conditions. Standard finite or boundary element methods require the number of degrees of freedom to grow at least linearly with respect to the frequency of the incident wave in order to maintain accuracy. Extending earlier work by Chandler-Wilde and Langdon for the sound soft problem, we propose a novel Galerkin boundary element method, with the approximation space consisting of the products of plane waves with piecewise polynomials supported on a graded mesh with smaller elements closer to the corners of the polygon. Theoretical analysis and numerical results suggest that the number of degrees of freedom required to achieve a prescribed level of accuracy grows only logarithmically with respect to the frequency of the incident wave.
Performance Analysis of a High-Order Discontinuous Galerkin Method Application to the Reverse Time Migration
Authors: Baldassari Caroline , Barucq Hélène , Calandra Henri , Denel Bertrand , Diaz Julien
Published: October 2011

This work pertains to numerical aspects of a finite element method based discontinuous functions. Our study focuses on the Interior Penalty Discontinuous Galerkin method (IPDGM) because of its high-level of flexibility for solving the full wave equation in heterogeneous media. We assess the performance of IPDGM through a comparison study with a spectral element method (SEM). We show that IPDGM is as accurate as SEM. In addition, we illustrate the efficiency of IPDGM when employed in a seismic imaging process by considering two-dimensional problems involving the Reverse Time Migration.
Relating sediment phosphorus mobility to seasonal and diel redox fluctuations at the sediment–water interface in a eutrophic freshwater lake
Authors: Smith Lydia , Watzin Mary C. , Druschel Gregory
Published: October 2011

Relationships between phosphorus cycling and redox conditions in the sediments of eutrophic Missisquoi Bay, Lake Champlain were investigated over diel and seasonal timescales in three consecutive summers (2007–2009), one of which (2007) did not experience a cyanobacteria bloom for the first time in a decade. Sediment extraction data showed that reactive phosphorus (RP) is strongly correlated to reactive iron (RFe), suggesting that the mobility of a large portion (30–40%) of the total sediment phosphorus pool is associated with nanocrystalline iron oxide minerals that may be influenced by redox conditions. RP concentrations in the top sediments increased throughout 2007 but decreased throughout 2008; calculations indicate that ~ 1 mm of sediment could account for the increased total dissolved phosphorus observed in overlying water. Redox conditions were measured over 24 h in situ within sediment cores and at the sediment–water interface (SWI) at different stages of each season using voltammetry. SWI redox conditions became progressively more reduced across the season and overnight and were significantly more reducing in the presence of a bloom. Soluble RP and cyanobacteria cell counts measured at five depths through the water column strongly correlated with the most reducing conditions at the SWI. Observations suggest that redox controlled nutrient flux between the sediments and the water column is variable over diel and seasonal cycles. Cyanobacteria blooms most significantly affect SWI redox conditions, suggesting that blooms may enhance RP flux from sediments, setting up a positive feedback loop that can propagate and sustain blooms in shallow freshwater systems.
Shutdown of turbulent convection as a new criterion for the onset of spring phytoplankton blooms
Authors: Taylor John R. , Ferrari Raffaele
Published: October 2011

The onset of phytoplankton blooms in late winter, early spring has been traditionally associated with the shoaling of the mixed layer above a critical depth. Here we show that the onset of a bloom can also be triggered by a reduction in air–sea fluxes at the end of winter. When net cooling subsides at the end of winter, turbulent mixing becomes weak, thereby increasing the residence time of phytoplankton cells in the euphotic layer and allowing a bloom to develop. The necessary change in the air–sea flux generally precedes mixed‐layer shoaling, and may provide a better indicator for the onset of the spring bloom than the mixed‐layer depth alone. Our hypothesis is supported by numerical simulations and remote sensing data.
Structure and seasonal dynamics of the eukaryotic picophytoplankton community in a wind‐driven coastal upwelling ecosystem
Authors: Collado-Fabbri Silvana , Vaulot Daniel , Ulloa Osvaldo
Published: October 2011

We studied the structure and seasonal dynamics of the photosynthetic picoeukaryote community at a coastal site off central Chile that is strongly affected by seasonal wind‐driven upwelling. We determined the picoeukaryote phylogenetic diversity by cloning and sequencing the 18S ribosomal ribonucleic acid (rRNA) gene amplified with Chloroplastida‐biased primers. Chloroplastida made up 100% (autumn), 61% (spring), and 20% (summer) of the clone libraries. Most sequences belonged to Mamiellophyceae and clustered with Micromonas (clades A.BC.1, B.E.3, C.D.5), Ostreococcus (clade A), and Crustomastix (clade A). Fluorescent in situ hybridization coupled with tyramide signal amplification (FISH–TSA) was used to determine the time variability in abundance of the total picoeukaryotic community, the Chloroplastida, and the genera Micromonas, Ostreococcus, and Bathycoccus over a period of 2 yr with nearly monthly sampling. The abundance of photosynthetic picoeukaryotes was low during the upwelling season (spring and summer) and high during the nonupwelling season (late fall and winter). Chloroplastida made up, on average, 74% of the total picoeukaryotic community, and the sum of the three genera probed accounted for 100% of the Chloroplastida abundances. Ostreococcus dominated the picophytoplanktonic community numerically throughout the year and, thus, appears to be a key component of the upwelling picoplanktonic community in the eastern South Pacific.