bluuebunny/crossref_metadata_2025 huggingface dataset:
A Lyapunov treatment of swarm coordination under conflict
Authors: McCullough Paul , Bacon Mark , Olgac Nejat , Sierra Daniel A. , Cepeda-Gomez Rudy
Published: November 2010

We consider hostile conflicts between two multi-agent swarms, called pursuers and evaders. A Newtonian dynamics-based double integrator model is taken into account, as well as a control strategy using the relative positions and velocities of opposing swarm members. This control is introduced to achieve stability and the capture of the evaders by the pursuers. The present document considers only swarms with equal membership strengths and equal mass for simplicity. This effort begins with a set of suggested interaction force profiles, which are functions of local vectors. To formulate a robust control law, a Lyapunov-based stability analysis is used. The group pursuit is conceived in two phases: the approach phase, during which the two swarms act like two individual agents, and the assigned pursuit phase, where each pursuer has an assigned evader. We show that the uncontrolled dynamics, which are marginally stable, are stabilized by the new controller.
Modal reduction of geared rotor systems with general damping and gyroscopic effects
Authors: Stringer DB , Sheth PN , Allaire PE
Published: November 2010

The presence of damping, gyroscopic behavior, and gearing complicates traditional vibration analysis. This paper presents a methodology for conducting modal reduction on a geared rotor dynamic system under the influences of general damping and gyroscopic effects. Based on the first-order, state-space methodology, a coordinate transformation is presented for diagonalizing the state equations of motion for each substructure in the system. A modal synthesis procedure assembles the system equations from the individual substructures. The substructures are coupled via gear-mesh interactions. Using this technique, the size and complexity of a model can be reduced without incurring significant loss of accuracy. The reduced model allows for traditional methods of system analysis to include eigen-solution analysis, and frequency response. Validation occurs through application to a simple geared system widely discussed in the literature. The results of the modal reduction match closely with the full finite element model. A transmission system is also analyzed to illustrate the method’s usefulness to a complex system model of multiple shafts and gear interactions. Considerations arising from the analysis of geared systems are also discussed.
Lowpass filter-based continuous-time approximation of delayed dynamical systems
Authors: Bo Song  , Sun Jian-Qiao
Published: November 2010

This paper extends our earlier work on continuous-time approximation of time-delayed dynamical systems by introducing a lowpass filter-based approach. The proposed method substantially improves the accuracy of predictions in frequency as well as time domain. It is applicable to linear and nonlinear dynamical systems, and can be readily incorporated with real-time controls. In the paper, we first review the mathematics literature on numerical methods for delayed differential equations including the equivalent abstract Cauchy problem. We show that the mathematics work provides a solid foundation for several well-studied numerical methods for time-delayed dynamical systems in the engineering literature. Examples are presented to show the accuracy of the pole prediction for linear systems, and temporal responses for linear and nonlinear systems. Furthermore, we discuss the bandwidth issue of the method, and demonstrate that many extraneous poles introduced by the discrete approximation of the time-delayed system that do not match any exact poles of the system are still very important and contribute to the accuracy of temporal responses.
Guided wave propagation in an isotropic solid subject to a bias
Authors: Simionescu-Panait Olivian , Ana Iulian
Published: November 2010

In the present paper we study the coupling conditions for propagation of planar guided waves in an isotropic semi-infinite plane subject to initial electromechanical fields. We obtain four different waves, two polarized in the sagittal plane, and two polarized transverse-horizontal, generalizing the classical guided waves from the case without initial fields. The initial electric field induces the electrostrictive effect for two of the waves. Finally, we analyze the corresponding mechanical and electric boundary conditions. As an example, we define and study a generalized Rayleigh-type wave.
Methods of assessing body fatness among children: Implications for the National Child Measurement Programme
Authors: Wheeler Sharon , Twist Craig
Published: November 2010

Body mass index (BMI) is increasingly recognized as an inadequate measure for determining obesity in children. Therefore, the aim within this study was to investigate other indirect methods of body fat assessment that could potentially be used in place of BMI. Twenty-four children (boys: 13.8 ± 0.8 yr; girls: 13.3 ± 0.5 yr) participated in this study. Measurements of BMI and waist-to-hip ratio (WHR) were obtained, along with percentage body fat (%BF) from skinfolds (SKF), bioelectrical impedance analysis (BIA) (arm-to-arm, leg-to-leg, arm-to-leg) and air displacement plethysmography (ADP). BMI was correlated with %BF from ADP (r = 0.45, p < 0.05), while WHR was not (r = 0.21, p > 0.05). %BF from the SKF method and all BIA methods demonstrated a significant relationship with ADP %BF (p < 0.05). The 95% limits of agreement (LoA) indicated that individual prediction errors between all BIA methods and ADP were large, while the SKF method showed strong agreement with ADP. The results of this study provide further evidence that the predictive accuracy of indirect methods for determining body fatness varies considerably with children. The findings are discussed in relation to the National Child Measurement Programme (NCMP), which is currently operating in primary schools in England.
The potential of the commonplace: A sociological study of emotions, identity and therapeutic change
Authors: Skatvedt Astrid , Schou Kirsten Costain
Published: November 2010

Aims: To explore aspects of treatment clients identify as having had a positive effect on their process of change. Method: The first author conducted data collection for one year through both participant observation and interviews. Results: Certain, apparently commonplace, informal interaction situations appear to constitute emotionally moving and identity-constructing contexts that have a significant impact on clients. These are situations in which new, ‘‘straight’’ identities can be proffered, tried out and explored. The situations in question seem to move clients, emotionally, mentally and biographically in a positive direction. Conclusions: The process of change is presented as an upside-down version of the traditional labelling theory: if normal people can be labeled as deviants, deviants can be re-labeled as normal. This study concludes that commonplace interactions are powerful labeling situations. These situations seem at first glance to be trivial, superficial and very common. Still, and perhaps because of their ‘‘smallness’’, they are identified as authentic and thereby trustworthy contributors to new narratives of worthy selves.
Overweight and waist circumference among Norwegian 11-year-olds and associations with reported parental overweight and waist circumference: The HEIA study
Authors: Bjelland M. , Lien N. , Bergh I.H. , Grydeland M. , Anderssen S.A. , Klepp K.-I. , Ommundsen Y. , Andersen L.F.
Published: November 2010

Aims: The aim of this paper is to investigate anthropometric characteristics in 11-year-old Norwegian by gender and parental education, and to study associations between adolescents’ overweight and waist circumference (WC) and maternal and paternal overweight and WC. Methods: A total of 1483 adolescents, 1156 mothers, and 1016 fathers participated in the baseline survey of the HEalth In Adolescents (HEIA) study (September 2007). Anthropometric measures of the adolescents were assessed by project staff according to standard procedures. Self-reported data about pubertal status were collected through questionnaires. Parental education and anthropometric measures of parents were collected by self-report. Results: The prevalence of overweight (including obesity) determined by the cut-offs for body mass index (BMI) suggested by the International Obesity Task Force was 14.6% among girls and 13.6% among boys. The highest prevalence of overweight was observed among adolescents with parents who had less than 12 years of education (18.8%). Overweight and WC in girls was strongly associated with maternal overweight and WC. For boys, overweight and WC was strongly associated with both maternal and paternal overweight and WC. Conclusions: There was a social gradient in anthropometric characteristics and overweight rates among Norwegian 11-year-old adolescents. Maternal overweight and WC was associated with overweight and WC in girls and boys, while paternal overweight and WC were associated with overweight and WC in boys. The results indicate that mothers are key persons in prevention of overweight among adolescents, despite gender. Fathers are important as role models for their sons. Targeting parental overweight/ obesity could be a strategy in future interventions.
Assessment of Pollutant Dispersion in the Re-entrance Space of a High-rise Residential Building, Using Wind Tunnel Simulations
Authors: Wang J.H. , Niu J.L. , Liu X.P. , Yu C.W.F.
Published: November 2010

This paper investigates the likely route of dispersion of airborne pollutants and pathogenic agents in the re-entrance space of a high-rise residential (HRR) building in Hong Kong. A 1 : 150 scaled HRR building, a 30 storeys tall model was tested in a wind tunnel with simulated atmospheric boundary layer flow. Tracer gas, propane released from the lower, middle and upper parts of the building, was measured by flame ionisation detection and this was used to simulate the air pollutant dispersion within the re-entrance space. There were a total of 495 measurements, tested under five different wind directions at 99 measurement points on windows locations of every floor of the modelled building. The tracer gas concentration profiles obtained would illustrate the pollutant dispersion and transmission routes under the different wind effect. The results showed that the airborne pollutants or pathogenic agents could be dispersed mainly along the vertical routes, posing a potential risk to the adjacent neighbours immediately above the source location. Wind direction could also affect the dispersion. The findings of this study should inform the development of ventilation strategies for HRR buildings and would guide building design to minimise transmission of airborne diseases or harmful pollutants within buildings.
A systematic review and meta-analysis of aliskiren and angiotension receptor blockers in the management of essential hypertension
Authors: Zhenfeng Zheng  , Huilan Shi  , Junya Jia  , Dong Li  , Shan Lin
Published: November 2010

Aliskiren is a novel antihypertensive agent and the first direct renin inhibitor (DRI) in clinical use. Several clinical trials have compared DRI with angiotensin receptor blockers (ARBs) in the management of essential hypertension. However, systematic comparison of efficacy and safety between DRIs and ARBs is still lacking. We reviewed randomized controlled trials (RCTs) comparing aliskiren with ARBs for net reduction of blood pressure from baseline, achieved rate of control, and incidences of common and serious adverse events. Weighted mean differences (WMD) and relative risk (RR) with 95% confidence intervals (CI) were calculated for continuous and dichotomous data, respectively. Seven RCTs with 5488 patients were included in this meta-analysis. We compared the efficacy of aliskiren and ARBs in reducing systolic blood pressure (SBP) and diastolic blood pressure (DBP). No differences were found between the two groups. Aliskiren combined with ARBs was superior to aliskiren monotherapy at the maximum recommended dose on SBP and DBP reduction. (WMD -4.80, 95% CI -6.22— -3.39, p < 0.0001; WMD -2.96, 95% CI -4.63—-1.28, p = 0.0001; respectively). Similar results were found with aliskiren combined with ARBs versus ARB monotherapy (WMD -4.43, 95% CI -5.91—-2.96, p < 0.0001; WMD -2.40; 95% CI -3.41—-1.39, p < 0.0001; respectively). No differences were found in adverse events between the aliskiren and ARB groups. Similar results were found with aliskiren and ARB combination therapy and its respective monotherapy. We conclude that aliskiren’s BP-lowering capabilities were comparable to those of ARBs. Aliskiren and ARB combination therapy provided more effective BP reduction than each respective monotherapy without increasing adverse events.
Phonological Processes in the Speech of Jordanian Arabic Children With Cleft Lip and/or Palate
Authors: Al-Tamimi Feda Y. , Owais Arwa I. , Khabour Omar F. , Khamaiseh Zaidan A.
Published: November 2010

The controlled and free speech of 15 Jordanian male and female children with cleft lip and/or palate was analyzed to account for the different phonological processes exhibited. Study participants were divided into three main age groups, 4 years 2 months to 4 years 7 months, 5 years 3 months to 5 years 6 months, and 6 years 4 months to 6 years 6 months, with bilateral or unilateral cleft lip and/or palate. Based on a productivity scale of a 20% or higher occurrence, results indicated the use of five productive processes: consonants backing, lateralization, depharyngealization, stopping, and final consonant deletion. Other phonological processes—for example, strident deletion, consonant harmony, fronting, syllable reduction, devoicing, liquid gliding, and deaffrication—did not reach the 20% or higher productivity scale. Age correlated significantly with the phonological processes, with the youngest group exhibiting these processes more than the other two groups did. There was no significant correlation between gender and phonological processes usage.
The Color of the Ethno/Graphic
Authors: Stich Amy E.
Published: November 2010

Anthropologist Michael Taussig calls it a “polymorphous magical substance.” This is how he “prefers to think of color, something more than a spot of red or blue on a page. It affects all the senses, not just sight. It moves. It has depth and motion, and it connects such that it changes whatever it comes into contact with.” Color is elusive. The ethno/graphic then must reflect the elusive as it falls into the unavoidable trappings of social research. Color may not be route out of a long series of inescapable research traps, but this ‘polymorphous magical substance’ brings us into the montage of the everyday to reveal meanings otherwise left concealed. The purpose of this reflective essay is to demonstrate color’s necessity within the trappings of social research that often remove color, and, as a result remove the soul, substance, and meaning, from the ethnographic.
Fathers Faring Poorly
Authors: Durette Rob , Marrs Chandler , Gray Peter B.
Published: November 2010

Fathers of young children may face health challenges. In this article, the authors sought to characterize health-related challenges among fathers of young children (aged 4 years or younger) through the use of an Internet survey. Questions covered an unusually large battery of outcomes related to men’s health, including general health, affect, and sexual function. A total of 126 adult fathers provided usable data. The most notable findings were that scores on the General Health Questionnaire, Kessler Psychological Distress Scale, and negative affect indicated poor general health and high levels of distress and negative affect compared with normative data. Relationship satisfaction, sexual desire, and sexual activity were similar to normative data, although sexual enjoyment with and without a partner were lower among fathers participating in this study. Some variables were associated with each other (e.g., relationship satisfaction and affect) but most were not. This study also indicates that fathers can be successfully recruited through Internet-based survey research.
Workforce development and challenging behaviour: training staff to treat, to manage or to cope?
Authors: Campbell Martin
Published: November 2010

Staff working directly with adults’ challenging behaviours in learning disability services need to be very good at what they do. They also need to want to do the job. A theory—practice gap exists, however, between what is known about effective, evidence-based approaches and whether and how these are used in person-centred community services. Many frontline staff working with people with the most serious challenging behaviours do not have the skills to implement programmes to change behaviour. This discussion article reviews workforce development in the context of clinical and service guidelines and asks whether the legitimate purview of frontline staff is treating challenging behaviour, managing it or simply coping with it on a daily basis, whilst maintaining the best quality of life possible for service users.
The impact of psychological distress on exacerbation rates in COPD
Authors: Laurin Catherine , Moullec Grégory , Bacon Simon L. , Lavoie Kim L.
Published: November 2010

Background: Exacerbations are common in chronic obstructive pulmonary disease (COPD) and contribute significantly to COPD morbidity and mortality. COPD is also associated with high levels of psychological distress, which has been shown to be associated with higher exacerbation rates. However, the existing literature on the association between psychological distress and exacerbation risk remains largely misunderstood.

Objectives: To critically review the current literature on the association between psychological distress (defined as anxiety and depressive symptoms or anxiety and depressive disorders) and COPD exacerbations in COPD patients, to highlight the limitations of the existing literature, and to provide recommendations for future research.

Methods: A critical review of English-language peer-reviewed longitudinal and retrospective studies was conducted. The Ovid portal to Medline, EMBASE, and PsycINFO databases were accessed.

Results: Some acceptable evidence suggested that psychological distress confers greater risk for exacerbations, more specifically symptom-based exacerbations or those treated in the patient’s own environment. However, most studies showed an absence of a positive association, especially with exacerbations leading to hospitalization.

Conclusions: Methodological weaknesses and the use of a wide range of psychological tools mean that there is an inconsistent association between psychological distress and exacerbations in the current literature. However, psychological distress may confer greater risk for symptom-based rather than event-based defined exacerbations. Further studies are needed to more comprehensively assess the question, particularly in light of the high levels of both anxiety and depression in COPD patients.
A role of ygfZ in the Escherichia coli response to plumbagin challenge
Authors: Lin Ching-Nan , Syu Wan-Jr , Sun Wei-Sheng W , Chen Jenn-Wei , Chen Tai-Hung , Don Ming-Jaw , Wang Shao-Hung
Published: November 2010

Plumbagin is found in many herbal plants and inhibits the growth of various bacteria. Escherichia coli strains are relatively resistant to this drug. The mechanism of resistance is not clear. Previous findings showed that plumbagin treatment triggered up-regulation of many genes in E. coli including ahpC, mdaB, nfnB, nfo, sodA, yggX and ygfZ. By analyzing minimal inhibition concentration and inhibition zones of plumbagin in various gene-disruption mutants, ygfZ and sodA were found critical for the bacteria to resist plumbagin toxicity. We also found that the roles of YgfZ and SodA in detoxifying plumbagin are independent of each other. This is because of the fact that ectopically expressed SodA reduced the superoxide stress but not restore the resistance of bacteria when encountering plumbagin at the absence of ygfZ. On the other hand, an ectopically expressed YgfZ was unable to complement and failed to rescue the plumbagin resistance when sodA was perturbed. Furthermore, mutagenesis analysis showed that residue Cys228 within YgfZ fingerprint region was critical for the resistance of E. coli to plumbagin. By solvent extraction and HPLC analysis to follow the fate of the chemical, it was found that plumbagin vanished apparently from the culture of YgfZ-expressing E. coli. A less toxic form, methylated plumbagin, which may represent one of the YgfZ-dependent metabolites, was found in the culture supernatant of the wild type E. coli but not in the ΔygfZ mutant. Our results showed that the presence of ygfZ is not only critical for the E coli resistance to plumbagin but also facilitates the plumbagin degradation.
A rapid and simple method for constructing stable mutants of Acinetobacter baumannii
Authors: Aranda Jesús , Poza Margarita , Pardo Belén G , Rumbo Soraya , Rumbo Carlos , Parreira José R , Rodríguez-Velo Patricia , Bou Germán
Published: November 2010

Background

Acinetobacter baumannii is a multidrug-resistant bacterium responsible for nosocomial infections in hospitals worldwide. Study of mutant phenotypes is fundamental for understanding gene function. The methodologies developed to inactivate A. baumannii genes are complicated and time-consuming; sometimes result in unstable mutants, and do not enable construction of double (or more) gene knockout mutant strains of A. baumannii.

Results

We describe here a rapid and simple method of obtaining A. baumannii mutants by gene replacement via double crossover recombination, by use of a PCR product that carries an antibiotic resistance cassette flanked by regions homologous to the target locus. To demonstrate the reproducibility of the approach, we produced mutants of three different chromosomal genes (omp33, oxyR, and soxR) by this method. In addition, we disrupted one of these genes (omp33) by integration of a plasmid into the chromosome by single crossover recombination, the most widely used method of obtaining A. baumannii mutants. Comparison of the different techniques revealed absolute stability when the gene was replaced by a double recombination event, whereas up to 40% of the population reverted to wild-type when the plasmid was disrupting the target gene after 10 passages in broth without selective pressure. Moreover, we demonstrate that the combination of both gene disruption and gene replacement techniques is an easy and useful procedure for obtaining double gene knockout mutants in A. baumannii.

Conclusions

This study provides a rapid and simple method of obtaining stable mutants of A. baumannii free of foreign plasmidic DNA, which does not require cloning steps, and enables construction of multiple gene knockout mutants.
Polymorphisms in regulatory regions of Cyclooxygenase-2 gene and breast cancer risk in Brazilians: a case-control study
Authors: Piranda Diogo N , Festa-Vasconcellos Juliana S , Amaral Laura M , Bergmann Anke , Vianna-Jorge Rosane
Published: November 2010

Background

Cyclooxygenase-2 (COX-2) is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Here, we evaluate the association between single-nucleotide polymorphisms (SNPs) in the COX-2 gene (PTGS2) and the occurrence of breast cancer among Brazilian women.

Methods

The study was conducted prospectively in two steps: First, we screened the promoter region and three fragments of the 3'-untranslated region ofPTGS2from 67 healthy Brazilians to identify SNPs and to select those with a minor allele frequency (MAF) of at least 0.10. The MAF of these selected SNPs was further characterized in 402 healthy volunteers to evaluate potential differences related to heterogeneous racial admixture and to estimate the existence of linkage disequilibrium among the SNPs. The second step was a case-control study with 318 patients and 273 controls designed to evaluatePTGS2genotype- or haplotype-associated risk of breast cancer.

Results

The screening analysis indicated nine SNPs with the following MAFs: rs689465 (0.22), rs689466 (0.15), rs20415 (0.007), rs20417 (0.32), rs20419 (0.015), rs5270 (0.02), rs20424 (0.007), rs5275 (0.22) and rs4648298 (0.01). The SNPs rs689465, rs689466, rs20417 and rs5275 were further studied: Their genotypic distributions followed Hardy-Weinberg equilibrium and the MAFs were not affected by gender or skin color. Strong linkage disequilibrium was detected for rs689465, rs20417 and rs5275 in the three possible pairwise combinations. In the case-control study, there was a significant increase of rs5275TC heterozygotes in cases compared to controls (OR = 1.44, 95% CI = 1.01-2.06; P = 0.043), and the haplotype formed by rs689465G, rs689466A, rs20417G and rs5275C was only detected in cases. The apparent association with breast cancer was not confirmed for rs5275CC homozygotes or for the most frequent rs5275C-containing haplotypes.

Conclusions

Our results indicate no strong association between the four most frequentPTGS2SNPs and the risk of breast cancer.
Nitrogen Availability for Sugarbeet affected by Tillage System and Sprinkler Irrigation Method
Authors: Stevens W. Bart , Evans Robert G. , Jabro Jay D. , Iversen William M.
Published: November 2010

Many shank‐type strip tillage (ST) implements band fertilizer below the seed without incorporating crop residue into the soil, potentially affecting N availability. Sprinkler irrigation method may also affect N availability due to its influence on water and NO3–N movement in soil. A field study was conducted at Sidney, MT, to determine if sugarbeet (Beta vulgaris L.) petiole NO3–N concentration and soil available (i.e., mineral) N distribution differ under (i) conventional tillage (CT) and ST systems and (ii) mid‐elevation spray application (MESA) and low energy precision application (LEPA) irrigation methods. Mid‐season petiole NO3–N concentration was lower with ST than with CT in 1 of 3 yr. In‐season mineral N concentration in the top 45 cm of soil was lower with ST than with CT. Postharvest mineral N was 10% lower with ST than with CT. There were few measurable effects of irrigation method except that in‐season mineral N in the top 45 cm of soil was 10% greater with LEPA than with MESA. Root yield and sugar production were reported to be similar with the two tillage systems. It was concluded that differences in petiole NO3–N concentration and soil mineral N content were not sufficient to justify altering N application rate based on the tillage systems or irrigation methods evaluated. However, there were indications that NO3–N leaching may be reduced by combining LEPA, with which irrigation water is applied between alternating crop rows, with strip tillage, where N is banded beneath the crop row.
Projections of air pollutant emissions and its impacts on regional air quality in China in 2020
Authors: Xing J. , Wang S. X. , Chatani S. , Zhang C. Y. , Wei W. , Hao J. M. , Klimont Z. , Cofala J. , Amann M.
Published: November 2010

Abstract. Anthropogenic emissions of air pollutants in China influence not only local and regional environments but also the global atmospheric environment; therefore, it is important to understand how China's air pollutant emissions will change and how they will affect regional air quality in the future. Emission scenarios in 2020 were projected using forecasts of energy consumption and emission control strategies based on emissions in 2005, and on recent development plans for key industries in China. We developed four emission scenarios: REF[0] (current control legislations and implementation status), PC[0] (improvement of energy efficiencies and current environmental legislation), PC[1] (improvement of energy efficiencies and better implementation of environmental legislation), and PC[2] (improvement of energy efficiencies and strict environmental legislation). Under the REF[0] scenario, the emission of SO2, NOx, VOC and NH3 will increase by 17%, 50%, 49% and 18% in 2020, while PM will be reduced by 10% over East China, compared to that in 2005. In PC[2], sustainable energy polices will reduce SO2, NOx and PM10 emissions by 4.1 Tg, 2.6 Tg and 1.8 Tg, respectively; better implementation of current control policies will reduce SO2, NOx and PM10 emission by 2.9 Tg, 1.8 Tg, and 1.4 Tg, respectively; strict emission standards will reduce SO2, NOx and PM10 emissions by 3.2 Tg, 3.9 Tg, and 1.7 Tg, respectively. Under the PC[2] scenario, SO2 and PM10 emissions will decrease by 18% and 38%, while NOx and VOC emissions will increase by 3% and 8%, compared to that in 2005. Future air quality in China was simulated using the Community Multi-scale Air Quality Model (CMAQ) with 2005 emissions and 2020 emission scenarios. Under REF[0] emissions, the concentrations of SO2, NO2, hourly maximum ozone in summer, PM2.5, total sulfur and nitrogen depositions will increase by 5~47%, 45~53%, 8~12%, 4~15%, 4~37% and 7~14%, respectively, over East China. Under the PC[2] emission scenario, the concentrations of SO2, NO2, hourly maximal ozone in summer, PM2.5, total sulfur and nitrogen depositions will change by −28%~16%, −1%~11%, 1%~2%, −24%~−12%, −24%~13%, and 0~3%, respectively. The individual impacts of SO2, NOx, NH3, NMVOC and primary PM emission changes on ozone and PM2.5 concentrations have been analyzed using sensitivity analysis. The results suggest that NOx emission control need to be enhanced during the summertime to obtain both ozone and PM2.5 reduction benefits. NH3 emission controls should also be considered in order to reduce total nitrogen deposition in the future.
Aerosol nucleation spikes in the planetary boundary layer
Authors: Chen J.-P. , Tsai T.-S. , Liu S.-C.
Published: November 2010

Abstract. Photochemically driven nucleation bursts, which typically occur in a few hours after sunrise, often produce strong aerosol number concentration (ANC) fluctuations. The causes of such ANC spikes were investigated using a detailed aerosol model running in the parcel mode. Two potential mechanisms for the ANC spikes are proposed and simulated. The blocking of actinic flux by scattered clouds can significantly influence new particle production, but this does not cause strong fluctuations in the number of aerosols within sizes greater than the detection limit of our measurements. A more plausible mechanism is the turbulence eddy effect. Strong aerosol nucleation may occur in both updrafts and downdrafts, while the cloud formation at the boundary layer top strongly reduces the number of aerosols. As the number of aerosols is sensitive to turbulence eddy and cloud formation properties, a changing turbulence condition would result in large fluctuations in the evolution of ANC similar to that observed at the surface.
McGill wetland model: evaluation of a peatland carbon simulator developed for global assessments
Authors: St-Hilaire F. , Wu J. , Roulet N. T. , Frolking S. , Lafleur P. M. , Humphreys E. R. , Arora V.
Published: November 2010

Abstract. We developed the McGill Wetland Model (MWM) based on the general structure of the Peatland Carbon Simulator (PCARS) and the Canadian Terrestrial Ecosystem Model. Three major changes were made to PCARS: (1) the light use efficiency model of photosynthesis was replaced with a biogeochemical description of photosynthesis; (2) the description of autotrophic respiration was changed to be consistent with the formulation of photosynthesis; and (3) the cohort, multilayer soil respiration model was changed to a simple one box peat decomposition model divided into an oxic and anoxic zones by an effective water table, and a one-year residence time litter pool. MWM was then evaluated by comparing its output to the estimates of net ecosystem production (NEP), gross primary production (GPP) and ecosystem respiration (ER) from 8 years of continuous measurements at the Mer Bleue peatland, a raised ombrotrophic bog located in southern Ontario, Canada (index of agreement [dimensionless]: NEP = 0.80, GPP = 0.97, ER = 0.97; systematic RMSE [g C m−2 d−1]: NEP = 0.12, GPP = 0.07, ER = 0.14; unsystematic RMSE: NEP = 0.15, GPP = 0.27, ER = 0.23). Simulated moss NPP approximates what would be expected for a bog peatland, but shrub NPP appears to be underestimated. Sensitivity analysis revealed that the model output did not change greatly due to variations in water table because of offsetting responses in production and respiration, but that even a modest temperature increase could lead to converting the bog from a sink to a source of CO2. General weaknesses and further developments of MWM are discussed.
A study on the compatibility and physical properties of chlorinated polyethylene rubber/nitrile rubber blends
Authors: Zhang Zhen Xiu , Chen Chun Hua , Gao Xin Wen , Kim Jin Kuk , Xin Zhen Xiang
Published: November 2010

The miscibility and some physicomechanical characteristics of chlorinated polyethylene rubber (CPE) and nitrile rubber (NBR) blends have been investigated. Calculation of the heat of mixing, differential scanning calorimetry, and scanning electron microscopy analysis showed that CPE was miscible with NBR in all proportions. The cure and scorch times decreased with the increase in NBR content, whereas the maximum torque increased. The tensile strength, 100% modulus, elongation at break, tear strength, and compression set decreased with increasing of NBR content. After aging, hardness and tensile strength increased, and there was no drastic change in elongation at break on aging. The thermal aging resistance and the abrasion resistance of NBR are improved after blending with CPE, but the oil resistance decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Ultra‐Slow Molecular Motion in Polymers: 1D and 2D NMR Spectroscopy
Authors: Blümich B. , Hagemeyer A. , Schmidt‐Rohr K. , Spiess H. W.
Published: November 2010

Different approaches of 1 D and 2 D solid state NMR spectroscopy for the detection of ultraslow molecular reorientation are reviewed with examples from 13C NMR: 2 D exchange spectroscopy of static powders is applicable generally for simple molecules only, because of spectral overlap. But the resulting spectra are readily interpreted in terms of jump and diffusive motion. More complex systems can be investigated with 1 D “inverse hole burning” spectroscopy or the 1 D magic angle spinning (MAS) method of exchange induced sidebands (EIS). 2 D MAS exchange spectra provide more specific information but are hard to interpret without computer simulations. The combination of 1 D EIS spectroscopy with rotor synchronization leads to 2 D spectra which correlate order and motion. The phase cycle for the TOSS (total suppression of sidebands) sequence needed in these experiments is given. The advantages of MAS and static exchange spectroscopy are combined in 2 D spectroscopy with sample spinning off the magic angle. 2 D exchange spectra similar to those of static samples are obtained for each chemical shift, however, the anisotropy is scaled down by the offset from the magic angle, resulting in increased spectral resolution.
Can Enantioselectivity be Computed in Enthalpic Barrierless Reactions? The Case of CuI‐Catalyzed Cyclopropanation of Alkenes
Authors: García José I. , Jiménez‐Osés Gonzalo , Mayoral José A.
Published: November 2010

An extensive computational study has been carried out on different catalytic systems for cyclopropanation reactions based on copper. Most DFT schemes used present drawbacks that preclude the calculation of accurate absolute kinetic properties (energy barriers) of such systems, excepting the M05 and M06 suites of density functionals. On the other hand, there is a wide range of DFT methods capable of reproducing relative energy values, which can be easily translated into selectivities. Most of the theoretical levels used tend to overestimate activation barriers, allowing the location of the transition state (TS) on the potential‐energy surface (PES) of the most reactive systems, which are probably artifacts of the method. However, after a thorough analysis of the calculated PES, and the origin of the energy differences obtained for the different alkene approaches in chiral systems, it is found that energy differences are almost constant over a wide range of geometries covering the reaction channel zone in which the true TS on the Gibbs free‐energy surface (GFES) lies. Therefore, many computational schemes can still be used confidently to explain and predict enantioselectivities in these systems.
Selection of simplified models: I. Analysis of model‐selection criteria using mean‐squared error
Authors: Wu Shaohua , McAuley K. B. , Harris T. J.
Published: November 2010

Mean‐squared error (MSE) is used to analyse nine commonly used model‐selection criteria (MSC) for their performance when selecting simplified models (SMs). Expressions are derived to enable exact calculations of the probability that a particular MSC will select a SM. For several common MSC, the relative propensities to select SMs are independent of model structure and data. It is shown that MSC that are effective in preventing overfitting are prone to underfitting when information content of the data is low. In a subsequent article, results are extended to develop a new MSE‐based MSC for selecting nonlinear multi‐response SMs.
Numerical simulation of the tissue ablation in high‐intensity focused ultrasound therapy with array transducer
Authors: Okita Kohei , Ono Kenji , Takagi Shu , Matsumoto Yoichiro
Published: November 2010

The development of high‐intensity focused ultrasound (HIFU) therapy for deeply situated cancer has been desired. One problem is focal point displacement due to the inhomogeneity of the human body. The objectives are the realization of appropriate phase control of an array transducer and support for preoperative planning of HIFU therapy by the computational prediction of ablation regions. To these ends, in this study we have developed an HIFU simulator that employs a voxel phantom constructed from CT/MRI data of a living human body. To reproduce the pressure propagation through an inhomogeneous medium, the mass and momentum equations for a mixture with the equation of state of the medium are solved. The ablation of tissue is modeled as a phase transition by using the phase field model. Then, the heat equation with viscous dissipation as a heat source and the Allen–Cahn equation with a free energy model are solved to predict the development of the ablation region. The basic equations are discretized by the finite difference method. HIFU therapy with an array transducer for liver cancer is reproduced numerically. Although the results without phase control show displacement and diffusion of the focal point due to the inhomogeneity of the human body, a clear focal point is obtained by using the array transducer with an appropriate phase delay obtained from pre‐computation. The HIFU simulator predicts that the ablation region will develop close to the target, owing to the phase control of the array transducer. Copyright © 2010 John Wiley & Sons, Ltd.
Proof interpretations with truth
Authors: Gaspar Jaime , Oliva Paulo
Published: November 2010

This article systematically investigates so‐called “truth variants” of several functional interpretations. We start by showing a close relation between two variants of modified realizability, namely modified realizability with truth and q‐modified realizability. Both variants are shown tobe derived from a single “functional interpretation with truth” of intuitionistic linear logic. This analysis suggests that several functional interpretations have truth and q‐variants. These variants, however, require a more involved modification than the ones previously considered. Following this lead we present truth and q‐variants of the Diller‐Nahm interpretation, the bounded modified realizability and the bounded functional interpretation (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibronic coupling in Frenkel and charge‐transfer states of oligothiophene crystals
Authors: Stradomska Anna , Kulig Waldemar , Petelenz Piotr
Published: November 2010

A novel approach, recently proposed to describe exciton–phonon coupling in Frenkel states of an infinite molecular crystal, is generalized to incorporate charge‐transfer (CT) excitons. Both types of electronic excitations are treated on the same footing. The corresponding Hamiltonian in the Lang–Firsov representation is subdivided into subspaces representing one‐particle, two‐particle, etc., excitations, and (after truncating the basis set to manageable size) numerically diagonalized to yield the absorption as well as the electroabsorption (EA) spectrum. The emphasis is on the latter, previously reproduced only in the limiting cases of weak or strong vibronic coupling. The calculations are presented for the sexithiophene crystal, with parameterization based on independent experimental and theoretical estimates.
Photoluminescence study of LaF3:Eu3+ nanoparticles capped with different ligands
Authors: Janssens Stefaan , Williams Grant , Clarke David , Sharp Matt
Published: November 2010

Temperature dependent photoluminescence (PL) measurements have been done on LaF3:Eu3+ nanoparticles capped with sensitizing or nonsensitizing ligands. The LaF3:Eu3+ nanoparticles containing a sensitizing ligand display a large enhancement of the PL intensity as well as an additional PL decay mechanism that is not seen in the LaF3:Eu3+ nanoparticles capped with nonsensitizing ligands. We also demonstrate that it is possible to obtain transparent discs, which is advantageous for device applications.

The image in the abstract shows cuvettes containing solutions of LaF3:Eu3+ capped with OA (left) and LaF3:Eu3+ capped with TTA/OA (right) in CHCl3 and excited at 365 nm.

magnified image
Value of autofluorescence bronchoscopy in patients with laryngeal cancer
Authors: Çetınkaya E , Veyseller B , Yildirim Y S , Aksoy F , Özgül M A , Gençoğlu A , Altin S
Published: November 2010

Background:

Patients with squamous cell carcinoma of the head and neck constitute a high risk group for synchronous and metachronous tumours.

Objective:

This study aimed to investigate the usefulness of white light and autofluorescence bronchoscopy in the evaluation of pre-malignant and early neoplastic lesions in patients with laryngeal cancer, who are at high risk of concomitant lung cancer.

Methods:

This prospective, cross-sectional study included 30 patients who had undergone total laryngectomy for squamous cell carcinoma of the larynx. The tracheobronchial system was investigated for the presence of pre-malignant and malignant lesions, using a combination of white light and autofluorescence bronchoscopy. Biopsies were obtained from areas with a pathological appearance, and histopathological studies were performed.

Results:

All patients had a permanent tracheostomy. Light and autofluorescence bronchoscopy indicated that the tracheobronchial system was normal in 11 patients. A total of 27 biopsies was taken from the remaining 19 patients, and revealed invasive squamous cell carcinoma in one patient and pre-malignant changes in six.

Conclusion:

Bronchoscopy is a valuable and practical tool for screening patients at high risk of lung cancer, and requires minimal intervention especially in patients with a permanent tracheostomy. Of the various bronchoscopic techniques becoming available, autofluorescence bronchoscopy shows promise for the detection of pre-invasive malignant changes of the tracheobronchial system in patients previously operated upon for laryngeal cancer.
Study of the formation of the “black cloud” and its dynamics over Cairo, Egypt, using MODIS and MISR sensors
Authors: Marey Heba S. , Gille John C. , El‐Askary Hesham M. , Shalaby Elsayed A. , El‐Raey Mohamed E.
Published: November 2010

In the past decade, episodes of severe air pollution, known as the “black cloud,” have occurred in Cairo, Egypt, in the early autumn. In this study, data from the Moderate Resolution Imaging Spectrometer (MODIS) and the Multi‐angle Imaging Spectroradiometer (MISR) are used with meteorological data and trajectory analyses to determine the cause of these events. MODIS fire counts put the source as the burning of agricultural waste after harvest season in the Nile delta region. Synchronous MISR data show that these fires create low altitude (<500 m) plumes of smoke and aerosols which flow over Cairo in a few hours, as confirmed by Hybrid Single‐Particle Lagrangian Integrated Trajectory (HYSPLIT) forward trajectory analyses. Much of the burning occurs at night, when an inversion constrains the plumes to remain in the boundary layer (BL). Convection during the day raises the BL, dispersing these smoke particles until the next night.
A generic approach for representing complex structures in biological models
Authors: Muetzelfeldt Robert
Published: November 2010

Increasingly, the biological modelling community is looking for ways of handling complex and possibly dynamic structures in their models. On the one hand, the pathway-modelling groups (SBML and CellML) seek to move up levels of organisation, while on the other hand the "Virtual X" communities (where X is some organism or organ) need to represent the organisational structure within their object of study. To date, various approaches have been proposed, such as the SBML Level 3 'comp', 'spatial', 'array' and 'dyn' extension packages, and domain-specific elements in languages such as NeuroML, but there is no generic approach intended to be adopted by the various communities.We have designed and implemented such a generic approach in the Simile modelling environment ("http://www.simulistics.com":http://www.simulistics.com). Simile combines a diagrammatic notation for ODEs (in terms of stocks, flows and subsidiary equations), combined with a UML-like notation for representing classes of object and associations between them. No domain-specific concepts are built in, so the object classes can represent anything from molecules to planets, and the associations are specified by the modeller. For example, Simile has no spatial concepts built in, but the modeller can create a class called (perhaps) 'spatial unit', and specify a regular (2- or 4-neighbour) square grid, a 3D array, a hexagonal grid or arbitrary polygons, simply by changing the expression which defines when the association exists between any pair of spatial units. Containership is represented simply by drawing one class inside another (so you can easily show that molecules are inside cells, and cells are inside organs), and objects can be dynamically created and destroyed during the simulation. Because Simile generates compiled C++ code for simulating model behaviour, it is capable of handling very complex models (1 million+ objects).We thus consider that Simile demonstrates the feasibility of a generic approach for handling disaggregation in biological models. We suggest that the widespread adoption of such an approach across the various biological modelling communities would greatly improve the efficiency and effectiveness of future model development as the models become increasingly complex.