bluuebunny/crossref_metadata_2025 huggingface dataset:
Behaviour of steel single angles subjected to eccentric axial loads
Authors: Liu Yi , Hui Linbo
Published: June 2010

The response of steel single angles subjected to axial eccentric loading is investigated by means of numerical modeling based on finite element techniques. Results show that in the case of eccentric compression causing major axis bending, a critical eccentricity for each slenderness ratio investigated exists and below this eccentricity, any reduction in the ultimate capacity due to eccentricity is marginal. The critical eccentricity increases with the slenderness ratio of the angle. In contrast, for the case of eccentric compression causing minor axis bending, the reduction in ultimate capacity, as affected by increasing eccentricity, is more pronounced and no similar critical eccentricity is identified. When compared with values determined from the design equations suggested in the AISC specification 2005, results indicate that the AISC equations, in general, give a satisfactory estimate of the ultimate capacity for angles subjected to axial compression and minor axis bending. For the case of eccentric compression causing major axis bending, AISC equations are conservative over a large range of parameters while they overestimate capacities in some other angles.
Physical and computational modelling of residence and flow development time in a large municipal disinfection clearwell
Authors: Yu Xiaoli , Mazurek Kerry Anne , Putz Gordon , Albers Cory
Published: June 2010

In this study, a two-dimensional, depth-averaged computational model (River2DMix) was used to predict the flow pattern and residence time distribution for flow through the Calgary Glenmore Water Treatment Plant northeast clearwell. Results are compared to those from flow visualization and tracer studies in a 1 : 19 scale model of the clearwell, as well as tracer studies conducted at the plant. Tests were carried out for three flow rates that ranged from minimum to maximum operating conditions. A key observation in the physical model was that it was necessary to let the flow fully develop before starting a tracer test to determine the residence time distribution. This flow development time to achieve steady-state results was approximately 10.5 h at the minimum flow rate tested. Results also show that it was unnecessary to model the structural columns either in the simulation or the scale model for developed flow in this clearwell, although for undeveloped or transient flow conditions the columns were important to consider.
Structural determination of the O-antigenic polysaccharide of enteropathogenicEscherichia coliO103:H2
Authors: Vinogradov Evgeny , MacLean Leann L. , Perry Malcolm B.
Published: June 2010

The structure of the antigenic O-polysaccharide isolated from the lipopolysaccharide produced by enterohemorrhagic Escherichia coli O103:H2 was determined and shown to be composed of d-glucose (1 part), 2-acetamido-2-deoxy-d-glucose (2 parts), 2-acetamido-2-deoxy-d-galactose (1 part), and 3-deoxy-3-(R)-3-hydroxybutyramido-d-fucose (1 part). From the results of methylation analysis, Smith-type periodate oxidation degradation studies, and the use of one- and two-dimensional1H and13C NMR spectroscopy, the O-polysaccharide antigen was found to be an unbranched polymer of a repeating pentasaccharide unit having the following structure: →2)-β-d-Glcp-(1→2)-β-d-Fucp3NBu-(1→6)-α-d-GlcpNAc-(1→4)-α-d-GalpNAc-(1→3)-β-d-GlcpNAc-(1→, where Bu is (R)-3-hydroxybutyramido.
Mycovirus inPseudocercospora griseola, the causal agent of angular leaf spot in common bean
Authors: Lima Swiany Silveira , Abadio Ana Karina Rodrigues , Araújo Elza Fernandes , Kitajima Elliot Watanabe , Sartorato Aloísio , Vieira de Queiroz Marisa
Published: June 2010

Pseudocercospora griseola (Sacc.) Crous & Braun is a widespread fungal phytopathogen that is responsible for angular leaf spot in the common bean ( Phaseolus vulgaris L.). A number of fungal phytopathogens have been shown to harbour mycoviruses, and this possibility was investigated in populations of Pseudocercospora griseola. The total nucleic acid extracts of 61 fungal isolates were subjected to agarose gel electrophoresis. Small fragments (800–4800 bp) could be identified in 42 of the samples. The presence of dsRNA in isolate Ig838 was confirmed by treatment of total nucleic acid with DNase, RNase A, and nuclease S1. Transmission electron microscopy revealed the presence of viral-like particles 40 nm in diameter in the mycelia of 2 fungal isolates, namely 29-3 and Ig838. The transmission of dsRNA by means of conidia was 100% for isolate 29-3, but there was loss of 1–6 fragments of dsRNA in monosporic colonies of isolate Ig848. Cycloheximide treatment failed to inhibit the mycovirus in isolate 29-3, but proved efficient in the elimination of the 2.2, 2.0, 1.8, 1.2 and 1.0 kb fragments in 2 colonies of isolate Ig848. The occurrence of a mycovirus in Pseudocercospora griseola was demonstrated for the first time in the present study.
Oral administration of Lactobacillus salivarius inhibits the allergic airway response in mice
Authors: Li Chia-Yang , Lin Hung-Chih , Hsueh Kai-Chung , Wu Shu-Fen , Fang Shih-Hua
Published: June 2010

Asthma is recognized throughout the world as a chronic airway inflammatory disease. In this study, we investigated the effect of probiotics in response to antigen challenge in an ovalbumin (OVA)-sensitized asthma model in BALB/c mice. Lactobacillus salivarius PM-A0006 was orally administered to mice before antigen challenge. After antigen challenge, serum OVA-specific antibody levels, airway responsiveness to methacholine, influx of inflammatory cells to the lung, and cytokine levels in bronchoalveolar lavage (BAL) fluid and splenocytes were assessed. Oral treatment with live L. salivarius PM-A0006 significantly attenuated the influx of eosinophils to the airway lumen and reduced the levels of serum OVA-specific IgE and eotaxin in BAL fluid of antigen-challenged animals. Furthermore, L. salivarius PM-A0006 also decreased allergen-induced airway hyperresponsiveness and elevated the levels of IFN-γ. These results showed that oral treatment with L. salivarius PM-A0006 could have therapeutic potential in the treatment of allergic airway disease.
Intragastric immunization of mice with enterohemorrhagicEscherichia coliO157:H7 bacterial ghosts reduces mortality and shedding and induces a Th2-type dominated mixed immune response
Authors: Cai Kun , Gao Xiang , Li Tao , Hou Xiaojun , Wang Qin , Liu Hao , Xiao Le , Tu Wei , Liu Yuenan , Shi Jing , Wang Hui
Published: June 2010

A bacterial ghost (BG)-based vaccine was developed against enterohemorrhagic Escherichia coli O157:H7 infection. The aim of this study was to evaluate the protective effect of E. coli O157:H7 BGs in a mouse model and to reveal the mechanism of the immune response. Booster immunization provided a higher protection rate (84%) than single-dose immunization (56%). Intragastric immunization of E. coli O157:H7 BGs induced both humoral and cellular immune responses. The proliferative response of CD4+T cells was mediated by the antigen-presenting cells. The humoral immune response dominated the immune response, while the cellular immune response developed later. Inflammatory reaction was balanced by the mixed Th1/Th2 immune response. The immune sera anti-adhesion effect was confirmed by the inhibition effect, which could inhibit >90% of the adhesion of E. coli O157:H7 to Hep-2 target cells in vitro. Antibody titer specific for intimin, a molecule important for adhesion of E. coli O157:H7 to target cells, correlated with specific immunoglobulin A or G antibody titer. Therefore, it might be feasible to clinically test BG vaccines in the future.
Microbial community characterization of the Gully: a marine protected area
Authors: Yeung C. William , Lee Kenneth , Whyte Lyle G. , Greer Charles W.
Published: June 2010

The Gully is the first Fisheries and Oceans Canada marine protected area off the eastern coast of Canada. To ensure success of conservation efforts in this area, it is essential to develop a better understanding of microbial community composition from the euphotic zone to the deep sea in this previously unsurveyed environment. Denaturing gradient gel electrophoresis (DGGE) and nucleotide sequencing were used to characterize microbial community structure. DGGE results showed a clear difference in the microbial community structure between the euphotic zone and the deep sea water. Cluster analysis showed high similarity (>85%) for all the samples taken from below 500 m, but lower similarity (49%–72%) when comparing samples from above and below 500 m. Changes in microbial community structure with depth corresponded well with changes in oceanographic physical parameters. Furthermore, 16S rRNA gene analysis showed that the bacterioplankton sequences generally clustered into 1 of 9 major lineages commonly found in marine systems. However, not all the major lineages were detected at all the different depths. The SAR11 and SAR116 sequences were only present in the surface water, and the SAR324 and Actinobacteria sequences were only present in deep sea water. These findings provide a preliminary characterization of the microbial communities of this unique ecosystem.
Exacerbation of acute viral myocarditis by tobacco smoke is associated with increased viral load and cardiac apoptosis
Authors: Bae Soochan , Ke Qingen , Koh Young Youp , Lee Wooseung , Choi Jun H. , Kang Peter M. , Morgan James P.
Published: June 2010

Exposure to tobacco smoke is known to have deleterious cardiovascular effects. In this study, we tested whether exposure to tobacco smoke exacerbates the severity of viral myocarditis in mice. Viral myocarditis was generated in 4-week-old male BALB/c mice by injection of Encephalomyocarditis virus (EMCV). Four groups were studied: (1) control (C, no smoke and no virus); (2) smoke only (S, exposure to cigarette smoke for 90 min/day for 15 days); (3) virus only (V); and (4) exposure to smoke for 5 days before plus 10 days following virus injection (S+V). We found that viral inoculation preceded by smoke exposure increased mortality more than twofold compared with virus inoculation alone. In addition, the mRNA level of atrial natriuretic factor was significantly higher in S+V than among any of the other 3 groups. Virus injection significantly decreased cardiac function compared with controls, with further deterioration observed in the S+V group. We also observed a significantly increased rate of apoptosis, with an increased activation of apoptosis-inducing factor in hearts exposed to S+V compared with those exposed to V alone. Our results suggest that preexposure to smoke significantly exacerbates the severity of viral myocarditis, likely through increased viral load and increased cardiomyocyte cell death.
Elevated dietary sugar and the heart: experimental models and myocardial remodeling
Authors: Mellor Kimberley M. , Ritchie Rebecca H. , Davidoff Amy J. , Delbridge Lea M.D.
Published: June 2010

A dramatic rise in the prevalence of insulin resistance has been paralleled by increasing dietary consumption of sugar. The use of added sweeteners containing fructose (sucrose and high-fructose corn syrup) has increased by 25% over the past 3 decades. High fructose intake has the potential to adversely influence systemic and cellular metabolism via insulin resistance and glycolytic dysregulation. As a tissue that is both insulin sensitive and glycolysis dependent, the heart may be especially vulnerable to fructose over-consumption. In this review, experimental studies of elevated dietary sugar intake are evaluated, including sucrose and fructose dietary manipulation models. The possible role of the GLUT5 transporter as a mediator of cardiomyocyte fructose uptake is considered. The impact of dietary sucrose and fructose on cardiac insulin-dependent signaling in the context of perturbed systemic metabolic response is detailed. Myocardial dysfunction, modified growth, and oxidative stress responses associated with high dietary sugar intake are discussed. Finally, the involvement of the renin–angiotensin system in mediating fructose cardiopathology is considered. This review highlights the importance of obtaining new mechanistic data that can contribute to a more developed understanding of how high sugar intake directly contributes to structural and functional cardiomyopathy.
Involvement of imidazoline and opioid receptors in the enhancement of clonidine-induced analgesia by sulfisoxazole
Authors: Boxwalla Mustufa , Matwyshyn George , Puppala Bhagya L. , Andurkar Shridhar V. , Gulati Anil
Published: June 2010

Clonidine, an α2-adrenergic agonist, has been demonstrated to produce significant analgesia and potentiate morphine analgesia. Endothelin (ETA) receptor antagonists have also been found to potentiate the antinociceptive response to morphine. Clonidine and ET have been reported to have cardiovascular interactions involving the sympathetic nervous system, but it is not known whether ETAreceptor antagonist affects clonidine analgesia. This study examined the influence of sulfisoxazole (ETAreceptor antagonist) on clonidine analgesia. Male Swiss Webster mice were used to determine antinociceptive response of drugs by measuring tail-flick latency. The effect of clonidine (0.3, 1.0, and 3.0 mg/kg, i.p.) alone or in combination with sulfisoxazole (25, 75, and 225 mg/kg, p.o.) on analgesia and body temperature was determined. Clonidine produced a dose-dependent analgesia and hypothermia. Sulfisoxazole (25, 75, and 225 mg/kg), when administered with clonidine (0.3 mg/kg), significantly potentiated (31% increase in area under the curve (AUC)) the analgesic effect of clonidine. Yohimbine (α2-adrenergic receptor antagonist) did not affect analgesic effect of clonidine plus sulfisoxazole. Idazoxan (I1-imidazoline and α2-adrenergic receptor antagonist) reduced (47% decrease in AUC) the analgesic effect of clonidine plus sulfisoxazole. Treatment with naloxone reduced (46% decrease in AUC) the analgesic effect of clonidine plus sulfisoxazole. The effect of another ETAreceptor antagonist, BMS-182874 (2, 10, and 50 µg, i.c.v.) was studied, and it was found that the dose of 10 µg significantly potentiated (26% increase in AUC) the analgesic effect of clonidine. These results indicate that sulfisoxazole, an ETAreceptor antagonist, potentiates the analgesic effect of clonidine, which could be mediated through I1-imidazoline receptors and opioid receptors.
The role of the DDAH–ADMA pathway in the protective effect of resveratrol analog BTM-0512 on gastric mucosal injury
Authors: Li Li , Luo Xiu-Ju , Liu Ying-Zi , Zhang Yi-Shuai , Yuan Qiong , Tan Na , Xiang Da-Xiong , Peng Jun
Published: June 2010

A recent study showed that resveratrol, a polyphenol found in many plant species, exerts dual effects on gastric mucosal injury. By using the model of ethanol-induced gastric mucosal injury in the present study, we explored the effect of trans-3,5,4′-trimethoxystilbene (BTM-0512), a novel analog of resveratrol, on gastric mucosal injury and the possible underlying mechanisms. Gastric mucosal injury in the rat was induced by oral administration of acidified ethanol. The gastric tissues were collected for determination of the gastric ulcer index, asymmetric dimethylarginine (ADMA) and nitric oxide (NO) contents, the activity of dimethylarginine dimethylaminohydrolase (DDAH) and superoxide anion (O2–) or hydroxyl radical (OH·) formation. The results showed that acute administration of ethanol significantly increased the gastric ulcer index concomitantly with the decrease in DDAH activity and NO content as well as the increase in ADMA content, effects that were reversed by pretreatment with BTM-0512 (100 mg/kg) or l-arginine (300 mg/kg). Administration of BTM-0512 did not show a significant effect on O2–or OH· formation. The results suggest that BTM-0512 could protect the gastric mucosa against ethanol-induced injury, which is mainly related to an increase in DDAH activity and subsequent decrease in ADMA content.
Mechanisms of oral bacteria-induced platelet activation
Authors: McNicol Archibald , Israels Sara J.
Published: June 2010

The oral cavity is inhabited by over 500 different bacterial species that normally exist in ecological balance both with each other and with the host. When this equilibrium is disturbed, an overgrowth of individual organisms can occur, which, in turn, can lead to the onset of pathological processes, notably dental caries and periodontitis. Generally, bacteraemias occur more frequently in individuals with periodontal disease, and these bacteraemias have been implicated in the development of a range of systemic diseases, including atherothrombotic disorders. The mechanism underlying this relationship remains to be precisely defined, although studies have shown a link between bacteria of oral origin and platelet activation. Several orally derived species of bacteria interact with platelets, including those of the Streptococcus ( Streptococcus sanguinis , Streptococcus mutans , Streptococcus agalactiae , Streptococcus pyogenes , Streptococcus gordonii , Streptococcus pneumoniae , Streptococcus mitis ) and Staphylococcus ( Staphylococcus epidermidis , Staphylococcus capitis ) genera, as well as Pseudomonas aeruginosa and Porphyromonas gingivalis . In addition, some members of both the Streptococcus and the Staphylococcus genera, as well as Porphyromonas gingivalis , can activate platelets in vitro. The current review describes the heterogeneous mechanisms of platelet activation employed by individual bacterial species. The pathological and clinical implications of platelet activation by orally derived bacteria are discussed.
Survival and nesting success of the Pacific Eider (Somateria mollissima v-nigrum) near Bathurst Inlet, Nunavut
Authors: Hoover A. K. , Dickson D. L. , Dufour K. W.
Published: June 2010

We used resighting data from 242 individually marked females to estimate apparent survival of Pacific Eiders ( Somateria mollissima v-nigrum Bonaparte, 1855) at a nesting colony in central arctic Canada from 2001 to 2007. In addition, we used data from nest searches conducted on islands at a freshwater lake and an adjacent marine environment to estimate annual breeding success. Annual survival rate estimates ranged from 0.84 ± 0.04 (mean ± SE) to 0.86 ± 0.05. Mayfield estimates of nest success ranged from 48.8% to 68.1% at the freshwater colony, and from 13.9% to 43.5% at the marine nesting colonies. The overwhelming cause of nest failure at both nesting areas was predation by grizzly bear ( Ursus arctos horribilis Ord, 1815), arctic fox ( Vulpes lagopus (L., 1758)), and wolverine ( Gulo gulo (L., 1758)). The majority of nests were initiated prior to ocean ice breakup in mid-July, thus mammalian predators had access to the islands well into incubation. Our results suggest that during the period from 2001 to 2007, the population of Pacific Eiders was likely not in decline. Therefore, the marked decline observed for eiders migrating past Point Barrow, Alaska, from 1976 to 1996 was more likely attributable to a stochastic event, such as unfavourable ice conditions, than to a chronic factor.
Fine-scale population structure and sex-biased dispersal in bobcats (Lynx rufus) from southern Illinois
Authors: Croteau Emily K. , Heist Edward J. , Nielsen Clayton K.
Published: June 2010

In mammal populations, the spatial and genetic structure can be affected by dispersal, philopatry, and relatedness. Bobcats ( Lynx rufus (Schreber, 1777)) are thought to exhibit typical mammalian dispersal behaviour where males disperse and females are philopatric, potentially leading to higher relatedness among females compared with males. We used 10 microsatellite loci to examine population structure and sex-biased dispersal in 146 bobcats sampled in southern Illinois during 1993–2001 using population genetic descriptive statistics, a Bayesian clustering algorithm, relatedness (rxy), and autocorrelation analyses. A randomization test demonstrated that female dyads had significantly higher rxy values with respect to randomly selected dyads (rxy = 0.093 ± 0.222, P = 0.012) and spatial autocorrelation analyses determined that females in close proximity (<5 km) had a high probability of being related (P = 0.001). Conversely, rxy values for males were not different from the null distribution (rxy = 0.019 ± 0.122, P = 0.3158) and no significant relationships were found with spatial autocorrelation analysis. Additionally, it was demonstrated that bobcats in southern Illinois approximated a panmictic population with no obvious barriers to gene flow. The pattern of relatedness observed in this study confirmed that females were philopatric and males dispersed, corroborating existing observational data for this species.
Nonideal habitat selection by a North American cavity excavator: pecking up the wrong tree?
Authors: Sadoti G. , Vierling K. T.
Published: June 2010

Nonideal habitat selection occurs when preferred habitat attributes differ from those associated with increased fitness. These mismatches have been widely studied in open cup-nesting birds, but the relationship between habitat-associated preferences and fitness in cavity-nesting birds has received relatively little attention. We studied patterns of preference and fitness during 2006–2007 in an Idaho, USA, population of Red-naped Sapsuckers ( Sphyrapicus nuchalis S.F. Baird, 1858). Using a suite of nonparametric tests, we examined the associations between habitat attributes and both nesting-area preferences and nest productivity (number of fledglings per pair) across four spatial scales. Nest productivity was associated with tree- and cavity-scale attributes, whereas preference was associated with attributes of home ranges. Live trees and southeasterly oriented cavities had higher nest productivity but were not preferred. Microclimates in nests with these attributes may enhance nestling survival, whereas nonpreference for these attributes may be due to energetic constraints in some individuals. Additional studies comparing patterns of nonideal habitat selection between open-cup nesters and cavity nesters should advance our understanding of how life-history characteristics influence selection patterns.
Marine nutrient transport: anadromous fish migration linked to the freshwater amphipod Gammarus fasciatus
Authors: Hanson Natalie , Fogel Marilyn , Fong Daniel W. , MacAvoy Stephen E.
Published: June 2010

Migrating anadromous fish may transfer marine-derived nutrients to oligotrophic tidal fresh water. River herrings (genus Alosa Linck, 1790) are the dominant anadromous genus in Virginia, USA. This study investigates whether marine nutrients derived from spawning Alosa spp. were incorporated into benthic invertebrates by using the stable isotopes of carbon and nitrogen. Spawning Alosa spp. had higher δ13C and δ15N values (–18.5‰ and 13.9‰, respectively) than resident freshwater omnivorous fishes (–25.7‰ and 11.8‰, respectively). In a tidal stream supporting abundant spawning Alosa spp., 13C and 15N enrichment was observed in stream amphipods (Gammarus fasciatus Say, 1818) coincident with the spawning migration of Alosa spp. The δ13C value for G. fasciatus increased from –28.5‰ to –26.0‰ from early to late April then fell to –28.1‰ in early June. A similar trend was observed in mayflies (Heptageniidae). Particulate organic matter and sediments from both streams remained depleted in 13C (between –29‰ and –28‰) and 15N (between 0.5‰ and 3.0‰) during the spawning run of Alosa spp. It is estimated that between 5% and 35% of amphipod biomass may be derived from marine carbon brought to tidal fresh water by spawning Alosa spp.
A cost of reproduction in male Atlantic cod (Gadus morhua)
Authors: Skjæraasen Jon E. , Meager Justin J. , Hutchings Jeffrey A.
Published: June 2010

In many species, females are thought to base their choice of mate on quality, which males signal through displays and body ornamentation. One important question is whether these signals represent an honest reflection of quality so that they carry an intrinsic cost to the male. A considerable body of evidence has revealed complex mating behaviours in gadoid fish, such as Atlantic cod ( Gadus morhua L., 1758), for which male reproductive success may be related to some form of female choice. However, if present, the cost of male signalling is not clear. To test the hypothesis that male behavioural displays are energetically costly, we quantified the number of displays initiated by males during spawning, and their corresponding mass loss, in two separate experiments. The number of displays was positively associated with mass loss in both experiments, suggesting that reproductive displays are costly to males; they also may be regarded as an honest signal of quality upon which females could base their choice of mate. To our knowledge, this is the first study to demonstrate a cost of male reproductive behaviour in a broadcast-spawning fish.
Distinctiveness of declining northern populations of Blanchard’s Cricket Frog (Acris blanchardi) justifies recovery efforts
Authors: Beauclerc Kaela B. , Johnson Bob , White Bradley N.
Published: June 2010

Peripheral populations of widespread species are often considered unworthy of conservation efforts; however, they may be adapted to the conditions found at the range edge and are therefore important to the future evolutionary potential of the species. Blanchard’s Cricket Frog (Acris blanchardi Harper, 1947) is widespread and abundant throughout the central United States, but is declining at the northern edge of its range. To assess the distinctiveness and conservation value of the northern populations, we investigated the spatial genetic structure and phylogeography of this anuran using mitochondrial control region sequences. Analysis of 479 individuals identified 101 haplotypes, with relatively low nucleotide diversity. Two moderately divergent clades were found. One was restricted to the southwest, which was probably a refugium during the Pleistocene, whereas the other occurred primarily across the north and is likely the result of postglacial colonization. The genetic distinctiveness of northern populations indicates the potential for adaptive differences of individuals in this region relative to those in the south. We therefore conclude that conservation efforts are justified for the declining northern populations of Blanchard’s Cricket Frog, and we use the spatial genetic structure described here to develop specific recommendations for this anuran.
Variability of hair cells in the coronal organ of ascidians (Chordata, Tunicata)
Authors: Caicci Federico , Degasperi Valentina , Gasparini Fabio , Zaniolo Giovanna , Del Favero Marcello , Burighel Paolo , Manni Lucia
Published: June 2010

The tunicate ascidians are nonvertebrate chordates that possess mechanoreceptor cells in the coronal organ in the oral siphon, which monitor the incoming water flow. Like vertebrate hair cells, the mechanoreceptor–coronal cells are secondary sensory (axonless) cells accompanied by supporting cells and they exhibit morphological diversities of apical specialisations: they are multiciliate in ascidians of the order Enterogona, whereas they are more complex and possess one or two cilia accompanied by stereovilli, also graded in length, in ascidians of the order Pleurogona. In morphology, embryonic origin, and arrangement, coronal sensory cells closely resemble vertebrate hair cells. We describe here the coronal organs of five ascidians ( Pyura haustor (Stimpson, 1864), Pyura stolonifera (Heller, 1878), Styela gibbsii (Stimpson, 1864), Styela montereyensis (Dall, 1872), and Polyandrocarpa zorritensis (Van Name, 1931)), belonging to Pleurogona, also comprising species of one family (Pyuridae), not yet considered, and thus completing our overview of the order. Each species possesses at least two kinds of secondary sensory cells, some of them characterized by stereovilli graded in length. In some species, the coronal sensory cells exhibit secretory activity; in P. haustor, a mitotic sensory cell has also been found. We compare the coronal organ in both ascidians and with other chordate sensory organs formed of secondary sensory cells, and discuss their possible homologies.
DATA COMPRESSION AND REGRESSION THROUGH LOCAL PRINCIPAL CURVES AND SURFACES
Authors: EINBECK JOCHEN , EVERS LUDGER , POWELL BENEDICT
Published: June 2010

We consider principal curves and surfaces in the context of multivariate regression modelling. For predictor spaces featuring complex dependency patterns between the involved variables, the intrinsic dimensionality of the data tends to be very small due to the high redundancy induced by the dependencies. In situations of this type, it is useful to approximate the high-dimensional predictor space through a low-dimensional manifold (i.e., a curve or a surface), and use the projections onto the manifold as compressed predictors in the regression problem. In the case that the intrinsic dimensionality of the predictor space equals one, we use the local principal curve algorithm for the the compression step. We provide a novel algorithm which extends this idea to local principal surfaces, thus covering cases of an intrinsic dimensionality equal to two, which is in principle extendible to manifolds of arbitrary dimension. We motivate and apply the novel techniques using astrophysical and oceanographic data examples.
A RIEMANNIAN DISTANCE APPROACH FOR CONSTRUCTING PRINCIPAL CURVES
Authors: ZHANG JUNPING , KRUGER UWE , WANG XIAODAN , CHEN DEWANG
Published: June 2010

The determination of principal curves relies on the arc-length as a global index to describe the middle of the data distribution. With a non-constant data distribution, however, curves that are constructed by the approach introduced in reference13may not reflect the middle of data distribution, as demonstrated in this article. This is particularly so for curve segments that have a large curvature and a high data density. To overcome this problem, the paper revisits the projection of the samples onto the curve by incorporating Riemannian distances. This analysis suggests estimating the density value of each sample relative to its neighbors and utilize this value to compute the projection index for the curve. The use of density values, in turn, allows penalizing distances between samples along with the arc-length. In a similar fashion to conventional principal curves algorithms, for example proposed by Hastie and Stuetzle14and Tibshirani,29the incorporation of Riemannian distances gives rise to an iterative algorithm that includes a projection and a self-consistent step. Application studies to simulated and experimental data sets shows that the proposed modification has the potential to outperform existing algorithms in areas of high curvature under an non-constant data distribution.
NETWORK COMPLEXITY AND SYNCHRONOUS BEHAVIOR — AN EXPERIMENTAL APPROACH
Authors: NEEFS P. J. , STEUR E. , NIJMEIJER H.
Published: June 2010

We discuss synchronization in networks of Hindmarsh-Rose neurons that are interconnected via gap junctions, also known as electrical synapses. We present theoretical results for interactions without time-delay. These results are supported by experiments with a setup consisting of sixteen electronic equivalents of the Hindmarsh-Rose neuron. We show experimental results of networks where time-delay on the interaction is taken into account. We discuss in particular the influence of the network topology on the synchronization.
DADE'S INVARIANT CONJECTURE FOR THE GENERAL UNITARY GROUP GU4(q2) IN DEFINING CHARACTERISTIC
Authors: AN JIANBEI , HUANG SHIH-CHANG
Published: June 2010

In this paper, we verify Dade's invariant conjecture for the general unitary group GU 4(q2), q a power of an odd prime p, in the defining characteristic p. Together with the results in [3], this completes the proof of Dade's invariant conjecture for the group GU 4(q2) in the defining characteristic.
OUTER AUTOMORPHISMS OF MAPPING CLASS GROUPS OF NONORIENTABLE SURFACES
Authors: ATALAN FERIHE
Published: June 2010

Let Ng be the connected closed nonorientable surface of genus g ≥ 5 and Mod (Ng) denote the mapping class group of Ng. We prove that the outer automorphism group of Mod (Ng) is cyclic.
A NOTE ON COMPLETELY PRIME IDEALS OF ORE EXTENSIONS
Authors: BHAT V. K.
Published: June 2010

The study of prime ideals has been an area of active research. In recent past a considerable work has been done in this direction. Associated prime ideals and minimal prime ideals of certain types of Ore extensions have been characterized.

In this paper a relation between completely prime ideals of a ring R and those of R[x; σ, δ] has been given; σ is an automorphisms of R and δ is a σ-derivation of R. It has been proved that if P is a completely prime ideal of R such that σ(P) = P and δ(P) ⊆ P, then P[x; σ, δ] is a completely prime ideal of R[x; σ, δ]. It has also been proved that this type of relation does not hold for strongly prime ideals.
BOREHOLE ACOUSTIC AND ELECTRIC STONELEY WAVES AND PERMEABILITY
Authors: PLYSHCHENKOV BORIS D. , NIKITIN ANATOLY A.
Published: June 2010

New way for quantitative evaluation of any value of formation permeability based on numerical experiments with Pride's model of electrokinetic phenomena is presented. This approach is based on simultaneous measurement of pressure field and axial component of electric field excited by an acoustic source in fluid-filled borehole with help a set of receivers in borehole. Frequency dependence of ratio of the complex-valued amplitudes of the electric Stoneley wave to the pressure Stoneley wave obtained as a result of plane-wave decomposition of pressure field and mentioned component of electric field carries important information about permeability. In case of open and sealed pores on borehole wall were obtained enough simple analytical expressions for this ratio.
3D ELASTODYNAMIC FINITE INTEGRATION TECHNIQUE SIMULATION OF GUIDED WAVES IN EXTENDED BUILT-UP STRUCTURES CONTAINING FLAWS
Authors: BINGHAM JILL , HINDERS MARK
Published: June 2010

In order to understand guided wave propagation through real structures containing flaws, a parallel processing, 3D elastic wave simulation using the elastodynamic finite integration technique (EFIT) has been developed. This full field, numeric simulation technique easily examines models too complex for analytical solutions, and is developed to handle built up 3D structures as well as layers with different material properties and complicated surface detail. The simulations produce informative visualizations of the guided wave modes in the structures as well as the output from sensors placed in the simulation space to mimic experiment.
COMPARISON OF TWO AND THREE SPATIAL DIMENSIONAL SOLUTIONS OF A PARABOLIC APPROXIMATION OF THE WAVE EQUATION AT OCEAN-BASIN SCALES IN THE PRESENCE OF INTERNAL WAVES: 100–150Hz
Authors: SPIESBERGER JOHN L.
Published: June 2010

Numerical solutions are given for a parabolic approximation to the acoustic wave equation at 100 and 150 Hz in two and three spatial dimensions to determine if azimuthal coupling in the horizontal coordinate significantly affects horizontal correlation in the presence of internal gravity waves in the sea. Coupling is a small effect at 4000 km. This implies that accurate solutions are possible using computations from uncoupled vertical slices. Shape of horizontal correlation is inconsistent with shapes given by two theories. Estimates of horizontal correlation at 4000 km and 100 and 150 Hz are about 1 km and 0.5 km respectively.
A MULTI-TIME-STEP STRATEGY BASED ON AN OPTIMIZED TIME INTERPOLATION SCHEME FOR OVERSET GRIDS
Authors: LIN DAKAI , JIANG MIN , LI XIAODONG
Published: June 2010

A multi-time-step strategy for overset grids is proposed based on an optimized time interpolation scheme. Time interpolation is adopted in the vicinity of the interface between adjacent blocks, which are marching in time with different time steps satisfying the local numerical stability. There is no strict constraint on the ratio of mesh sizes between neighboring blocks, and it can alleviate the burden of the grid generation for multi-time-step marching methods. The optimized time interpolation scheme can be simply combined with the existing typical time marching schemes to achieve multi-time-step marching for overset grids. Some numerical examples are presented to demonstrate the feasibility and efficiency of the proposed strategy.
FINDING THE BEST DESIGN WITHIN LIMITED TIME: A COMPARATIVE CASE STUDY ON METHODS FOR OPTIMIZATION IN STRUCTURAL ACOUSTICS
Authors: RANJBAR MOSTAFA , HARDTKE HANS-JÜRGEN , FRITZE DENNY , MARBURG STEFFEN
Published: June 2010

A combination of a commercially available finite element software package and additional user-written programs is used to modify the shape of a square plate made of steel. The structure's local geometry modification values at the selected surface key-points are considered as design variables. The objective of the optimization includes the minimization of the root mean square level of structure borne sound. The optimization process continues automatically until the predefined maximum number of function evaluations is reached. A statistical approach is followed for the comparison of seven different optimization methods. It will be shown that the method of moving asymptotes and the mid-range multi-point method produce the best results to find a substantial improvement of the objective function within a limited number of function evaluations.
STABILITY ANALYSIS OF PLATES WITH PARTIAL RESTRAINTS USING UNCONSTRAINED OPTIMIZATION TECHNIQUES
Authors: BEDAIR OSAMA
Published: June 2010

A procedure is presented for stability analysis of thin plates subject to any combination of in-plane shear, biaxial compression, and bending. Unlike finite element or finite strip methods, where the plate is discretized into a set of elements or strips, the plate here is treated as a single element. An energy-based formulation is used to express the buckling coefficient, K, in terms of general functions that describe the longitudinal and transverse displacement profiles. The longitudinal edges are treated as partially restrained against rotation (PRR) and in-plane translation. Unconstrained optimization technique is then used to determine the minimum combinations of pre-selected geometric plate parameters. Accuracy of the derived expressions is compared with the Galerkin method for the limiting simply supported and clamped boundary conditions. Results are then presented for plates PRR and in-plane translation.
DYNAMIC RESPONSES OF TRANSMISSION TOWER-LINE SYSTEM UNDER ICE SHEDDING
Authors: YANG FENGLI , YANG JINGBO , HAN JUNKE , FU DONGJIE
Published: June 2010

Ice shedding from conductors may easily induce electrical and mechanical accidents, which cause a serious threat to the safe operation of transmission lines. In this paper, a 3D finite element model of tower-conductor-ground wire-insulator system was established in ANSYS, and the dynamic responses of ice shedding under different cases were analyzed for a transmission tower-line system. The computed jumping heights are in excellent agreement with the experimental values of a two span conductors model. Many variables were considered in the ice-shedding simulations that include tower-line coupled effect, phase combination of the ice-shedding conductors, thickness of the accreted ice, length of the ice-shedding span as well as elevation difference. Influences of all the variables on the dynamic responses of jumping heights, loads at the end of insulators and the forces of transmission tower were studied. Ice-shedding simulations of an actual 500 kV transmission line section which experience failure under ice shedding in 2008 were performed. The results show that stress ratios of members at the tower head under design ice thickness exceed the limiting values when the amount of shedding ice is large. For ice shedding at the top phase conductors, the jumping height and unbalanced tension at the end of insulator can be reduced by applying interphase spacers in triangular arrangement. The tower is in a safe state under the load of the design ice thickness. In order to prevent ice-shedding accidents, interphase spacers should be used, and the weak members at the tower head should be strengthened according to the calculated load values at the end of insulators.
ACTIVE VIBRATION CONTROL OF SEISMICALLY EXCITED STRUCTURES BY ATMDS: STABILITY AND PERFORMANCE ROBUSTNESS PERSPECTIVE
Authors: MOHTAT ARASH , YOUSEFI-KOMA AGHIL , DEHGHAN-NIRI EHSAN
Published: June 2010

This paper demonstrates the trade-off between nominal performance and robustness in intelligent and conventional structural vibration control schemes; and, proposes a systematic treatment of stability robustness and performance robustness against uncertainty due to structural damage. The adopted control strategies include an intelligent genetic fuzzy logic controller (GFLC) and reduced-order observer-based (ROOB) controllers based on pole-placement and linear quadratic regulator (LQR) conventional schemes. These control strategies are applied to a seismically excited truss bridge structure through an active tuned mass damper (ATMD). Response of the bridge-ATMD control system to earthquake excitation records under nominal and uncertain conditions is analyzed via simulation tests. Based on these results, advantages of exploiting heuristic intelligence in seismic vibration control, as well as some complexities arising in realistic conventional control are highlighted. It has been shown that the coupled effect of spill-over (due to reduction and observation) and mismatch between the mathematical model and the actual plant (due to uncertainty and modeling errors) can destabilize the conventional closed-loop system even if each is alone tolerated. Accordingly, the GFLC proves itself to be the dominant design in terms of the compromise between performance and robustness.
BRIDGE VIBRATION UNDER VEHICULAR LOADS: TIRE PATCH CONTACT VERSUS POINT CONTACT
Authors: YIN XINFENG , CAI C. S. , FANG ZHI , DENG LU
Published: June 2010

When establishing the equations of motion of the bridge-vehicle coupling system, most researchers simplify the contact between the vehicle tire and road surface as a point contact. In reality, a vehicle tire deforms and makes contact with the road surface over a footprint area called patch contact. This paper presents a new method that allows for the effect of the patch contact on the dynamic response of the bridge-vehicle coupling system. In this method, the vehicle tire is modeled as a two-dimensional elementary spring model, and the patch contact is assumed to be a rectangle. The bridge-vehicle coupling equations are established by combining the equations of motion of both the bridge and vehicle using the displacement relationship and interaction force relationship at the patch contact. A series of simulation studies have been carried out in which the effects of various factors such as vehicle speed, tire stiffness and damping, size of the patch contact, number of vehicles, and faulting condition have been investigated. The numerical simulations and field test results show that the proposed method can more rationally simulate the interaction between the bridge and vehicles.
Preparation of N-bridged diiron phthalocyanines bearing bulky or small electron-withdrawing substituents
Authors: Işci Ümit , Dumoulin Fabienne , Ahsen Vefa , Sorokin Alexander B.
Published: June 2010

The synthesis of novel μ-nitrido diiron phthalocyanine with electron-withdrawing substituents is reported: μ-nitrido tetra-methylsulfonylphthalocyanine (13), μ-nitrido tetra-ethylsulfonylphthalocyanine (14), μ-nitrido tetra-adamantylsulfonylphthalocyanine (15), μ-nitrido tetra-cyclohexylsulfonylphthalocyanine (16). These complexes were characterized by ESI-MS, UV-vis, FT-IR and EPR techniques. The state of these complexes depends on the size of the substituents. Complexes 13 and 14 bearing small methylsulfonyl and ethylsulfonyl substituents are cationic ( PcFe IV NFe IV Pc )+ N 3- complexes while complexes 15 and 16 with bulkier adamantylsulfonyl and cyclohexylsulfonyl substituents are formally neutral PcFe III NFe IV Pc complexes which can be represented as PcFe (+3.5) NFe (+3.5) Pc .
Tetrakis(thiadiazole)porphyrazines: 7. Synthesis and structure of μ-oxo-bis[tetrakis(thiadiazole)porphyrazinato-aluminum(III)]
Authors: Donzello Maria Pia , Fujimori Masato , Miyoshi Yasuhito , Yoshikawa Hirofumi , Viola Elisa , Awaga Kunio , Ercolani Claudio
Published: June 2010

The complex μ-oxo-bis[tetrakis(thiadiazole)porphyrazinato-aluminum(III)], [( TTDPzAl )2 O ], has been obtained from the corresponding mononuclear Al(III) hydroxo-complex, [ TTDPzAlOH ], by refluxing a solution of this latter in α-chloronaphthalene or by heating the solid hydroxo species (250–300 °C) under vacuum (10-2 mmHg). The complex, which appears as a stable species in air, shows a typical IR absorption at 983 cm-1, assigned as ν as (Al-O-Al) . Contact with water determines disappearance of this absorption consequent to the formation of the related hydroxide. [( TTDPzAl )2 O ], insoluble in most organic non-donor solvents, and very scarcely soluble in dimethylsulfoxide and dimethylformamide, shows some instability in pyridine, with probable breaking of the μ-oxo bridge and formation of the mononuclear hydroxide. Single crystals suitable for X-ray analysis were obtained by subliming [( TTDPzAl )2 O ] under vacuum at 500 °C under a continuous N 2 flow. Crystal data for [( TTDPzAl )2 O ], C 32 Al 2 N 32 OS 8: a = 7.613(2) Å, b = 11.280(2) Å, c = 23.363(5) Å, β = 96.869(3)°, space group P21/c ( n . 14), U = 1991.9(7) Å3, Z = 2, R(F)a = 0.0492, wR(F2) = 0.1024. The μ-oxo bridged complex has a central linear Al-O-Al bond system, with the Al(III) atoms displaced out of the respective N 4 square planar coordination sites by 0.441 Å and the two TTDPz planes lying in an eclipsed position, the overall structure of the complex approaching closely that of the related phthalocyaninato complex [( PcAl )2 O ]. Intermolecular contacts, instead, are definitely different for the two species, the type found present in [( TTDPzAl )2 O ] highly reminiscent of those of other previously reported "thiadiazoleporphyrazine" macrocycles, with the observed short inter-unit contacts between adjacent TTDPz macrocycles again determined by the presence in the TTDPz framework of the annulated peripheral (S, N) -containing heterocycles.
Transition from free rotation of C70 molecules to static disorder in the molecular C70 complex with covalently linked porphyrin dimers: {(FeIIITPP)2O}·C70
Authors: Konarev Dmitri V. , Khasanov Salavat S. , Lyubovskaya Rimma N.
Published: June 2010

Fullerene C 70 and covalently linked porphyrin ( Fe III TPP )2 O dimers (TPP: tetraphenylporphyrin) form molecular complex {( Fe III TPP )2 O }· C 70 (1). Each C 70 molecule is sandwiched between two ( Fe III TPP )2 O dimers and is surrounded by phenyl groups of four other porphyrin dimers. At 295 K, C 70 molecules freely rotate about the short axis of the molecule in the ab plane. As a result, the disordered C 70 molecules form spheroids flattened at the poles. The rotation of C 70 stops near 100 K, resulting in the transition from a tetragonal to a monoclinic unit cell with a four-fold increase in the unit cell volume. In monoclinic phase the C 70 molecules are located on the axis which coincides with the short axis of the molecule and passes through the midpoints of two oppositely located 6-6 bonds. Since this position has higher symmetry than the own symmetry of C 70, it results in statistic disorder of the C 70 molecules between two orientations. It was shown that multiple Van der Waals contacts with a concave Fe III TPP macrocycle which appear below 100 K, play an important role in the ordering of C 70.
ON DYNAMICS OF ℓ-VOLTERRA QUADRATIC STOCHASTIC OPERATORS
Authors: ROZIKOV U. A. , ZADA A.
Published: June 2010

We introduce a notion of ℓ-Volterra quadratic stochastic operator defined on (m - 1)-dimensional simplex, where ℓ ∈ {0,1,…, m}. The ℓ-Volterra operator is a Volterra operator if and only if ℓ = m. We study structure of the set of all ℓ-Volterra operators and describe their several fixed and periodic points. For m = 2 and 3, we describe behavior of trajectories of (m - 1)-Volterra operators. The paper also contains many remarks with comparisons of ℓ-Volterra operators and Volterra ones.