bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Virtual Reality Simulation Through Product Lifecycle
Authors: Ikonomov Pavel G. , Milkova Emiliya D.
Published: May 2008

This papers present using Virtual reality (VR) simulation trough product lifecycle for product testing that would lead to better new products without faults. Using complete VR product simulation for new products, from design, manufacturing, and maintenance to the end-user and recycle state allows the end-user to test the virtual products, and by providing feedback to reduces design errors and contribute for better design. After production the same VR product simulation can be used for training, virtual user manual virtual user manual, virtual repair maintenance, and for disassembly before recycle. A framework for building VR simulation for designed products is described and working application examples are provided. An expanding of the VR simulation applications for using with extensive range of computation platforms and devices is proposed.
Design Logic of a Cannabinoid Receptor Signaling Network That Triggers Neurite Outgrowth
Authors: Bromberg Kenneth D. , Ma'ayan Avi , Neves Susana R. , Iyengar Ravi
Published: May 2008

Cannabinoid receptor 1 (CB1R) regulates neuronal differentiation. To understand the logic underlying decision-making in the signaling network controlling CB1R-induced neurite outgrowth, we profiled the activation of several hundred transcription factors after cell stimulation. We assembled an in silico signaling network by connecting CB1R to 23 activated transcription factors. Statistical analyses of this network predicted a role for the breast cancer 1 protein BRCA1 in neuronal differentiation and a new pathway from CB1R through phosphoinositol 3-kinase to the transcription factor paired box 6 (PAX6). Both predictions were experimentally confirmed. Results of transcription factor activation experiments that used pharmacological inhibitors of kinases revealed a network organization of partial OR gates regulating kinases stacked above AND gates that control transcription factors, which together allow for distributed decision-making in CB1R-induced neurite outgrowth.
Comment on "Habitat Split and the Global Decline of Amphibians"
Authors: Cannatella David C.
Published: May 2008

Becker
et al
. (Reports, 14 December 2007, p. 1775) reported that forest amphibians with terrestrial development are less susceptible to the effects of habitat degradation than those with aquatic larvae. However, analysis with more appropriate statistical methods suggests there is no evidence for a difference between aquatic-reproducing and terrestrial-reproducing species.
Response to Comment on "Habitat Split and the Global Decline of Amphibians"
Authors: Fonseca Carlos Roberto , Becker Carlos Guilherme , Haddad Célio Fernando Baptista , Prado Paulo Inácio
Published: May 2008

Habitat split, defined as human-induced disconnection between habitats used by different life history stages of a species, is a strong factor negatively affecting the richness of Brazilian Atlantic Forest amphibians. Here, the disconnection between streams and forest fragments is shown to reduce the proportion of species with aquatic larvae in local communities.
Metasomatized Lithosphere and the Origin of Alkaline Lavas
Authors: Pilet Sébastien , Baker Michael B. , Stolper Edward M.
Published: May 2008

Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that partial melts of metasomatic veins can reproduce key major- and trace-element features of oceanic and continental alkaline magmas. Moreover, experiments with hornblendite plus lherzolite showed that reaction of melts of amphibole-rich veins with surrounding lherzolite can explain observed compositional trends from nephelinites to alkali olivine basalts. We conclude that melting of metasomatized lithosphere is a viable alternative to models of alkaline basalt formation by melting of recycled oceanic crust with or without sediment.
Rethinking History for a New Islamic Science
Authors: Murphy Jane H.
Published: May 2008

Science and Islam
.
By Muzaffar Iqbal
. Greenwood, Westport, CT, 2007. 269 pp. $65, £37.95. ISBN 9780313335761. Greenwood Guides to Science and Religion.

The author combines a historical survey of scientific achievements in the Islamic tradition with a call for a new science.
Widespread Translational Inhibition by Plant miRNAs and siRNAs
Authors: Brodersen Peter , Sakvarelidze-Achard Lali , Bruun-Rasmussen Marianne , Dunoyer Patrice , Yamamoto Yoshiharu Y. , Sieburth Leslie , Voinnet Olivier
Published: May 2008

High complementarity between plant microRNAs (miRNAs) and their messenger RNA targets is thought to cause silencing, prevalently by endonucleolytic cleavage. We have isolated
Arabidopsis
mutants defective in miRNA action. Their analysis provides evidence that plant miRNA–guided silencing has a widespread translational inhibitory component that is genetically separable from endonucleolytic cleavage. We further show that the same is true of silencing mediated by small interfering RNA (siRNA) populations. Translational repression is effected in part by the ARGONAUTE proteins AGO1 and AGO10. It also requires the activity of the microtubule-severing enzyme katanin, implicating cytoskeleton dynamics in miRNA action, as recently suggested from animal studies. Also as in animals, the decapping component VARICOSE (VCS)/Ge-1 is required for translational repression by miRNAs, which suggests that the underlying mechanisms in the two kingdoms are related.
Bridging the Cultural Divide
Authors: Gowers W. Timothy
Published: May 2008

Beyond Measure
. Conversations Across Art and Science.
Barry Phipps, Curator
. Kettle's Yard, Cambridge. Through 1 June 2008.
www.kettlesyard.co.uk/exhibitions/beyond.html

Beyond Measure
. Conversations Across Art and Science.
By Barry Phipps
. Kettle's Yard, Cambridge, 2008. Paper, 48 pp. £6.95. ISBN 9781904561262.

This exhibition at Kettle's Yard, Cambridge, explores geometry in science, current art, and the links between them.
Comparison between Pernasal Flocked Swabs and Nasopharyngeal Aspirates for Detection of Common Respiratory Viruses in Samples from Children
Authors: Abu-Diab Afaf , Azzeh Maysa , Ghneim Raed , Ghneim Riyad , Zoughbi Madeleine , Turkuman Sultan , Rishmawi Nabeel , Issa Abed-El-Razeq , Siriani Issa , Dauodi Rula , Kattan Randa , Hindiyeh Musa Y.
Published: May 2008

In this prospective study we compared the use of pernasal flocked swab samples with the use of nasopharyngeal aspirate (NPA) samples for the detection of respiratory viruses from 455 children less than 5 years of age. Overall, the sensitivity and the specificity of the pernasal flocked swab samples were 98.5% and 100%, respectively. The excellent sensitivity of the flocked swab samples in combination with the rapid means by which they may be collected makes them an alternative to NPA samples, whose collection is more invasive.
In Vitro-Generated Antigen-Specific CD4+CD25+Foxp3+Regulatory T Cells Control the Severity of Herpes Simplex Virus-Induced Ocular Immunoinflammatory Lesions
Authors: Sehrawat Sharvan , Suvas Susmit , Sarangi Pranita P. , Suryawanshi Amol , Rouse Barry T.
Published: May 2008

Generating and using regulatory T cells (Tregs) to modulate inflammatory disease represents a valuable approach to therapy but has not yet been applied as a means to control virus-induced immunopathological reactions. In this report, we developed a simplified technique that used unfractionated splenocytes as a precursor population and showed that stimulation under optimized conditions for 5 days with solid-phase anti-CD3 monoclonal antibody in the presence of transforming growth factor β (TGF-β) and interleukin-2 could induce up to 90% of CD4+T cells to become Foxp3+and able to mediate suppression in vitro. CD11c+dendritic cells were intricately involved in the conversion process and, once modified in the presence of TGF-β, could convert Foxp3−CD4+cells into Foxp3+CD4+cells by producing TGF-β. The converted cells had undergone cell division, and the majority of them expressed activation markers along with surface molecules that would facilitate their migration into tissue sites. The primary reason for our study was to determine if such in vitro-converted Tregs could be used in vivo to influence the outcome of a virus-induced immunoinflammatory lesion in the eye caused by herpes simplex virus infection. We could show in three separate models of herpetic stromal keratitis that adoptive transfers of in vitro-converted Tregs effectively diminished lesion severity, especially when given in the initial phases of infection. The suppression effect in vivo appeared to be polyspecific. The protocol we have developed could provide a useful additional approach to control virus-induced inflammatory disease.
CDK13, a New Potential Human Immunodeficiency Virus Type 1 Inhibitory Factor Regulating Viral mRNA Splicing
Authors: Berro Reem , Pedati Caitlin , Kehn-Hall Kylene , Wu Weilin , Klase Zachary , Even Yasmine , Genevière Anne-Marie , Ammosova Tatiana , Nekhai Sergei , Kashanchi Fatah
Published: May 2008

The human immunodeficiency virus type 1 (HIV-1) Tat is a 14-kDa viral protein that acts as a potent transactivator by binding to the transactivation-responsive region, a structured RNA element located at the 5′ end of all HIV-1 transcripts. Tat transactivates viral gene expression by inducing the phosphorylation of the C-terminal domain of RNA polymerase II through several Tat-activated kinases and by recruiting chromatin-remodeling complexes and histone-modifying enzymes to the HIV-1 long terminal repeat. Histone acetyltransferases, including p300 and hGCN5, not only acetylate histones but also acetylate Tat at lysine positions 50 and 51 in the arginine-rich motif. Acetylated Tat at positions 50 and 51 interacts with a specialized protein module, the bromodomain, and recruits novel factors having this particular domain, such as P/CAF and SWI/SNF. In addition to having its effect on transcription, Tat has been shown to be involved in splicing. In this study, we demonstrate that Tat interacts with cyclin-dependent kinase 13 (CDK13) both in vivo and in vitro. We also found that CDK13 increases HIV-1 mRNA splicing and favors the production of the doubly spliced protein Nef. In addition, we demonstrate that CDK13 acts as a possible restriction factor, in that its overexpression decreases the production of the viral proteins Gag and Env and subsequently suppresses virus production. Using small interfering RNA against CDK13, we show that silencing of CDK13 leads to a significant increase in virus production. Finally, we demonstrate that CDK13 mediates its effect on splicing through the phosphorylation of ASF/SF2.
TOBACCO ETCH IN PEPPERS IN SOUTHERN ONTARIO
Authors: McKeen C. D.
Published: May 2008

Tobacco etch is one of the most prevalent and injurious viruses on sweet peppers in southern Ontario. The virus occurs in several strains. Detailed descriptions of symptoms produced by etch on sweet, hot, and semihot varieties of peppers are described. Symptoms on the pepper fruits have been observed chiefly on the sweet types. The widespread occurrence of etch in peppers is attributed to the prevalence of the vector Myzus persicae Sulz. Possible sources of etch that may give rise to epidemics on pepper and tobacco crops in southern Ontario are discussed.
THE CLASSIFICATION OF RECENTLY DISCOVERED CRETACEOUS PLANT MICROFOSSILS OF POTENTIAL IMPORTANCE TO THE STRATIGRAPHY OF WESTERN CANADIAN COALS
Authors: Radforth Norman W. , Rouse Glenn E.
Published: May 2008

Seven thin coal seams from the uppermost Cretaceous strata (Brazeau) of Western Alberta are investigated with the purpose of revealing the existence of classifiable fossil spores and pollens which may be significant as index units in stratigraphic differentiation. Thirty-four microfossils are classified, described, and illustrated. Relationships to previously known macrofossils or modern plants are suggested. One spore is bryophytic, nine are pteridophytic in affiliation, and one microfossil type possibly represents a fungal spore. Twelve pollens show gymnosperm relationship, and 11 fall within the Angiospermae. A distributional pattern indicates occurrences and associations of 14 microfossils occurring in frequencies of 5% or greater within the coals. Differences between the Brazeau macro- and microflora are evalutated in terms of applicability to stratigraphic definition.
CYTOLOGICAL STUDIES OF CHROMOSOMES OF RUST FUNGI: II. THE MITOTIC CHROMOSOMES OF PUCCINIA CORONATA
Authors: McGinnis R. C.
Published: May 2008

Germinating sporidia of Puccinia coronata Corda f. sp. secalis Peturs. were examined cytologically during mitotic nuclear division to determine the chromosome number. Studies at metaphase and anaphase revealed a haploid number of three chromosomes in this rust. The possibility of a polyploid series in the genus Puccinia is discussed.
STUNT OF CLOVERS, CAUSED BY RHIZOCTONIA SOLANI
Authors: Benedict W. G.
Published: May 2008

Evidence is presented to prove that stunting of clovers in Essex County, Ontario, in 1952 was caused by root parasitizing strains of Rhizoctonia solani Kühn (Corticium solani (Prill. & Del.) Bourd. & Galz.). Typical symptoms of stunt were reproduced in greenhouse tests with isolates of this fungus but the isolates varied in their pathogenicity to red clover, alfalfa, sweet clover, and alsike clover.
LIFE HISTORY STUDIES OF THE PACIFIC COAST MARINE ALGA, COLLINSIELLA TUBERCULATA SETCHELL AND GARDNER
Authors: Scagel Robert F.
Published: May 2008

Culture studies of a marine green alga, described from the Pacific Coast of North America as Collinsiella tuberculata Setchell and Gardner, have shown it to be a stage in the life history of a form of Enteromorpha intestinalis (L.) Link. The Collinsiella-stage is thought to be the sexual phase, or a basal remnant of the Enteromorpha-stage, and produces biflagellate gametes. The typical tubular thallus of Enteromorpha has been grown in culture from zygotes of the Collinsiella-stage and zoospores of the Enteromorpha-stage. Parthenogenetic development of gametes is also indicated. Some of the tubular plants produce biflagellate gametes which cannot be distinguished from those of the Collinsiella-stage. Others produce quadriflagellate zoospores, which may be meiospores or mitospores. An accessory method of reproduction by quadriflagellate mitospores (neutral spores) occurs and this asexual cycle has been carried through three successive generations in culture without an intervening sexual phase. Tubular thalli of Enteromorpha inteslinalis (L.) Link producing biflagellate gametes during the spring and early summer and quadriflagellate zoospores during the late summer are found in nature in the same area from which the Collinsiella-stage was obtained. These are believed to represent in nature the normal sexual life cycle of this plant, which has been reported to have an alternation of isomorphic generations. The possible relationships between the stages obtained in culture and those observed in nature are discussed. A number of hypothetical conclusions have been drawn with respect to the systematic position of the genus Enteromorpha and related genera. These studies are being continued to clarify several unknown aspects brought out by this preliminary study. A cytological study is being undertaken to substantiate the conclusions drawn from the morphological data.
THE EFFECT OF NODE TEMPERATURE ON ASSIMILATION AND TRANSLOCATION OF C14 IN THE SQUASH
Authors: Webb J. A. , Gorham P. R.
Published: May 2008

Varying the primary leaf node temperature from 0 to 45 °C did not alter the rate of either C14O2 assimilation or transpiration of the leaf blade. In contrast, the rate of C14-sugar export from the blade was markedly influenced by the node temperature. At 0 °C there was no significant movement of C14 through the node, but a slow export of C14-stachyose and C14-sucrose did continue from the blade into the petiole above the chilled node. This was associated with an abnormal accumulation of C14-sugars in the blade, where the accumulated C14-stachyose showed little metabolic turnover. Above 0 °C and typical of the response of many physiological mechanisms to temperature, the rate of C14 movement through the node increased to a maximum at 25 °C and fell again to zero at 55 °C. The exports from the blade of C14-stachyose and C14-sucrose were equally affected by the different temperature treatments at the node. The inhibitory effect of chilling on translocation was reversible, whereas the effect of heating to 55 °C was irreversible. When the node was rapidly returned from 0 to 25 °C a slow export from the blade began immediately but the normal rate was not restored until approximately 60 minutes later. It is concluded that translocation of sugar through the node and basal region of the squash petiole is under direct physiological control. The process does not appear to be closely correlated with protoplasmic streaming.
AN ANALYSIS AND CLASSIFICATION OF WHITE SPRUCE COMMUNITIES IN RELATION TO CERTAIN HABITAT FEATURES
Authors: Groenewoud H. Van
Published: May 2008

Physiognomy, ratio between percentage moss and herb cover, significant associations between species, and soil texture were used to group vegetation samples containing white spruce into community types.The averages of the "measured mean" pH, the minimum pH, and the maximum pH of three soil layers, the height growth of the white spruce trees, and the nitrogen content of the white spruce foliage of the community types were compared by t test. When a significant difference showed that the samples were drawn from different populations, this was taken to justify the acceptance of the community types as distinct entities with regard to the features investigated.Of the five community types originally recognized, only three were retained. They were respectively the Equisetum pratense type, the Equisetum arvense type, and a very variable community type typified by a more or less developed moss–herb–shrub vegetation.
Fasciation d'extrémités caulinaires du Celosia cristata (Amarantacées) cultivées in vitro
Authors: Driss-Ecole D.
Published: May 2008

In vitro development of fasciation was achieved from the excised shoot apices of Celosia cristata in a 16-h photoperiod. An 8-h photoperiod produced no development. The explants consisted of the meristematic dome with two leaf primordia. The best results were obtained with a nutrient medium composed of Murashige and Skoog salt mixture, 30 g/L sucrose, 5 g/L agar, and 1 mg/L indoleacetic acid (IAA). Isolated shoot apices developed callus at the bases of the explants and numerous leaves on one, two, or three flattened and fasciated meristems. Root initiation occurred sometimes but only after a long period of culture.
A preliminary checklist of the mosses and lichens in the Fort McMurray area, Alberta, Canada
Authors: Douglas George W. , Peterson Wilbur L. , Skorepa Allen C.
Published: May 2008

One hundred and sixteen species of lichens and 138 species of mosses are reported from the little collected Fort McMurray region of northeastern Alberta. Several significant range extensions are noted. Six lichen species (Chaenotheca chrysocephala, Dermatocarpon moulinsii, Lecanora polytropa, Physcia millegrana, Physconia grisea, and Ramalina pollinaria) and two moss species (Calliergidium pseudostramineum and Hygroamblystegium noterophilum) are new to the flora of Alberta.
Biomass and mineral capital of epiphytes in an Acer macrophyllum community of a temperate moist coniferous forest, Olympic Peninsula, Washington State
Authors: Nadkarni Nalini M.
Published: May 2008

The epiphyte community of a Pacific northwest temperate rain forest makes up a conspicuous portion of the canopy, especially on the Acer macrophyllum trees that grow along river terraces of wet western slopes of the Olympic Mountains. Destructive sampling methods were used to assess the composition, biomass, and nutrient concentrations of live and dead epiphytes on representative host trees to determine the mineral capital contained in the epiphytic components of the standing vegetation. Average epiphyte standing crop on mature Acer macrophyllum trees is 35.5 kg. The nutrient capital (grams) is N, 370; P, 44; K, 145; Ca, 270; Mg, 50; and Na, 9. Although epiphyte biomass constitutes less than 2% of total aboveground ecosystem dry weight, it is equivalent to nearly four times the foliar biomass of host trees on a single-tree basis. Epiphytes are efficient at garnering nutrients from atmospheric sources and retaining them within the biotic portion of the ecosystem. They supplement the nutrient-gathering apparatus of host trees and buffer nutrient pulses on a short-term and on a seasonal basis.
The distribution and status of Acorus (Araceae) in Canada
Authors: Packer John G. , Ringius Gordon S.
Published: May 2008

Evidence is presented documenting the occurrence in Canada of two Acorus species. One is a widespread fertile diploid with which the name A. americanus has been associated. The other is a sterile taxon of more limited distribution, no doubt representing the well-known sterile triploid A. calamus of Europe, which has been widely introduced into North America.
Studies in Crataegus. XI. Further cytological evidence for the occurrence of apomixes in North American hawthorns
Authors: Muniyamma M. , Phipps J. B.
Published: May 2008

This paper extends to seven species in four series the number of North American Crataegus for which agamospermy is reported. All the taxa investigated are from Ontario and apospory, often facultative, is found in all the cases reported here. The significance of these findings to North American Crataegus taxonomy and evolution is discussed.
Effect of fracture deformation on fluid pressure distribution—an indicator of slope instability
Authors: Gale John E. , Witherspoon Paul A.
Published: May 2008

Results from laboratory and field tests on fractured rock systems have shown that changes in fluid pressure within a fracture can cause changes in the effective normal stress that result in significant normal displacements. These normal displacements change the fluid pressure distributions and hence the shear strength of the fracture system. The nature of the normal displacement (opening or closing of the fracture) can be detected by comparing the ratios of pressures measured at two points within the fracture plane. Other workers have shown in laboratory shear tests on rough fractures that movement along discontinuities, prior to failure, has both a normal and tangential component. Careful measurement of changes in fluid pressures in fractured rock slopes should be able to detect the effects of such normal displacements and thus give an indication of an approaching instability.
A comparison of joints in bedrock and fractures in overlying Pleistocene lacustrine deposits, central Alberta
Authors: Babcock E. A.
Published: May 2008

A comparison of bedrock joints with fractures in outcrops of fine-grained Quaternary glaciolacustrine deposits indicates that fractures in the lacustrine sediments are not related to underlying bedrock joints. Fractures in the silts are caused by an exfoliation type of weathering occurring at the outcrop face. They are not reliable indicators of a possible fracture fabric pervading the deposit away from the outcrop scarps.
Exact determination of gravity stresses in finite elastic slopes: Part I. Theoretical considerations
Authors: Silvestri V. , Tabib C.
Published: May 2008

The exact distributions of gravity stresses are obtained within slopes of finite height inclined at various angles, −β (β = π/2, π/3, π/4, π/6, and π/8), to the horizontal. The solutions are obtained by application of the theory of a complex variable. In homogeneous, isotropic, and linearly elastic slopes under plane strain conditions, the gravity stresses are independent of Young's modulus and are a function of (a) the coordinates, (b) the height, (c) the inclination angle, (d) Poisson's ratio or the coefficient of earth pressure at rest, and (e) the volumetric weight. Conformal applications that transform the planes of the various slopes studied onto the upper half-plane are analytically obtained. These solutions are also represented graphically.
Exact determination of gravity stresses in finite elastic slopes: Part II. Applications
Authors: Silvestri V. , Tabib C.
Published: May 2008

Influence diagrams are presented for the gravity stresses arising in excavated finite elastic slopes inclined at various angles, −β (β = π/2, π/3, π/4, π/6, and π/8), with respect to the horizontal. These influence diagrams are calculated for a value of the earth pressure coefficient at rest, K0, equal to 0.50. Several examples are worked out and adequately illustrate the application of the influence charts and of the general solution. Finally, the results obtained from the exact solution are compared with those published in the literature, which were obtained by means of numerical (finite element) and experimental (photoelasticity) methods.
A deep retaining structure in till and sand. Part I: Stress path effects
Authors: Medeiros L. V. , Eisenstein Z.
Published: May 2008

Laboratory investigation of the stress–strain behaviour of glacial till (stiff silty clay) and dense preglacial sand have been carried out. Special attention has been devoted to investigation of the influence of different stress paths on the stress–strain response of these materials. Since these tests were performed primarily for an analytical study of the behaviour of a deep retaining structure, the stress paths chosen for testing were typical of stress conditions for this field situation. Triaxial and plane strain drained tests on till were run in passive compression (with increasing major principal stress and constant minor principal stress) and in active compression (with constant major principal stress and decreasing minor principal stress). On the sand, only triaxial tests were carried out. These experiments were in passive compression and in active extension (with decreasing major principal stress and constant minor principal stress).The results of different tests were compared at corresponding stress and strain levels. They indicated an appreciably decreased stiffness along the passive compression stress path compared with that in the active compression and active extension tests. Also, a comparison between the triaxial and plane strain tests for the till showed a marked influence of the intermediate principal stress. Although the results were intended for use in a stress path dependent, nonlinear elastic analysis they are discussed and explained in terms of a more general elastoplastic model of soil behaviour. Keywords: stress–strain relationship, stress path, laboratory testing, stiff clay, dense sand.
A deep retaining structure in till and sand. Part II: Performance and analysis
Authors: Eisenstein Z. , Medeiros L. V.
Published: May 2008

The problem of magnitude and distribution of lateral pressure acting on a deep retaining structure supporting an excavation in till and sand is studied by an approach integrating field measurements from a case history with a finite element analysis. Also studied are ground movements associated with the excavation. The finite element analysis is based on stress path dependent testing of the soils involved.The case history is the behaviour of a deep supported wall of the underground Churchill Square Station of the recently built line of the Light Rail Transit System in Edmonton. A tangent pile wall, 17 m deep, has been placed through glacial till to underlying sands. The site has been instrumented to record displacements of the wall and of the surrounding ground as well as the loads carried by the lateral supports.A finite element analysis employing several stress–strain models was used to simulate the excavation and its sequence, the placement of lateral support, and the differential stiffness of the structural components and of the surrounding soil. Special attention has been given to the effect of different stress–strain models of soils, with a particular focus on the influence of stress paths typical for the studied structure.Agreement between the field and analytical results for displacements is accepted as a criterion of validity of the analytical results of stresses, where direct in situ stress measurements are difficult to obtain and interpret. Of special importance is the calculated lateral pressure against the wall and its relation to the stiffness of the wall and to the magnitude of associated ground movements. The calculated lateral pressure has been found to differ significantly from the semiempirical design pressure diagrams used in practice.The soil stress–strain model found to describe the field behaviour most closely has been derived from test results obtained using a plane strain apparatus. Keywords: deep supported excavation, displacement, lateral pressure, field measurement, finite element analysis.
Bearing capacity of shallow footing, sand over clay
Authors: Kraft Jr. Leland M. , Helfrich Steven C.
Published: May 2008

Measured results of full-scale and model bearing capacity tests are compared with predictions from projected area methods and with a more rigorous method developed by Hanna. The results of the comparisons for these 27 cases support the procedure developed by Hanna. The ratio of predicted to observed bearing capacity was 0.99, and the standard deviation was 0.23.
Analysis of foundation settlements at Ridgway Dam
Authors: Chugh Ashok K. , Davidson Luther W.
Published: May 2008

The foundation material at the Ridgway Dam site is broadly classified as mudstone. The observed foundation settlements along the invert of the river outlet-works conduit at Ridgway Dam are on the order of 0.3 m. Numerical analyses were performed to estimate the deformation properties for a foundation material that under the existing embankment loads would deflect in a manner similar to the settlements surveyed along the invert of the outlet-works conduit. The foundation deformation properties determined from these analyses are compared with those obtained through the laboratory testing of the site-specific foundation materials and the published data. The results of the analyses, the field instrumentation data, the site geology, and the laboratory data provided an input to the decision-making process for the rehabilitation of the river outlet- works conduit. Key words: foundations, settlements, embankment dams, mudstones, analysis.
Evaluation of minimum factor of safety in slope stability analysis
Authors: Chen Zu-Yu , Shao Chang-Ming
Published: May 2008

This paper explores the feasibility of using optimization methods to search for the minimum factor of safety in slope stability analysis. The routine procedure includes comparing a number of admissible surfaces that are basically selected by random searches. Low efficiency and unreliability are the problems commonly encountered.Optimization methods allow a mathematically rigorous and reliable search for the minimum factor of safety and its associated "critical slip surfaces." This paper employs simplex, steepest descent, and Davidon – Fletcher – Powell (DFP) methods. The results of a number of test problems, in conjunction with closed-form and grid search solutions, showed that all the above-mentioned methods can provide reasonable results. Case history analyses supported the feasibility of the methods. Modifications to the DFP method were found to be essential for successful implementation of the minimization procedure. Key words: slope stability, landslide, analysis, limit equilibrium, interslice forces, factor of safety, spline function, optimization methods, case history.
Thermal volume changes of the mineral–water system in low-porosity clay soils
Authors: Baldi G. , Hueckel T. , Pellegrini R.
Published: May 2008

The effect of temperature on the volumetric strains of the clay skeleton and clay – water system has been examined experimentally. Heating tests at (various) constant effective stress and isotropic loading tests at (various) constant temperatures were performed on low-porosity clays under drained conditions. The results indicate that the thermal expansion of adsorbed water in these clays is significantly lower than that of free water. Depending on the effective pressure, the clay skeleton may undergo either compression or expansion. Key words: nuclear waste isolation, clay, low porosity, thermal strain, adsorbed water.
Efficient bioconversion of palm acid oil and palm kernel acid oil to poly(3-hydroxybutyrate) by Cupriavidus necator
Authors: Kek Yik-Kang , Lee Wing-Hin , Sudesh Kumar
Published: May 2008

Efficient bioconversion of palm oil by-products to green materials serves as a prominent way to overcome wastage. Generally, major palm oil by-products such as palm acid oil (PAO) and palm kernel acid oil (PKAO) are used for animal feed. This pioneer study investigated the ability of Cupriavidus necator H16 (ATCC 17699) (formerly Ralstonia eutropha) to biologically convert these by-products to poly(3-hydroxybutyrate) [P(3HB)]. P(3HB) was synthesized when PAO or PKAO was fed as the sole carbon source. However, it was found that PKAO is superior with respect to higher amount of P(3HB) accumulation in 48 h (85 wt% of the dry cell mass). In addition, important culture parameters were identified, such as nitrogen sources and ratio of culture volume to flask volume, which significantly affected the P(3HB) content. The nitrogen concentration in the culture medium is very crucial in promoting the biosynthesis of P(3HB). The highest P(3HB) yield (3.1 g/L) was initiated at 4 mmol/L of urea. Less than 0.4 g/L of P(3HB) was obtained when 30.0 mmol/L or higher urea concentrations were used. This study has identified a suitable process to produce high P(3HB) yield from major palm oil by-products. It is also demonstrated that C. necator H16 has suitable metabolic pathways that allow the conversion of palm oil by-products to P(3HB) effectively. Hereby, surplus palm oil by-products can be converted to a relatively high-value and sustainable product.Key words: poly(3-hydroxybutyrate), palm oil, palm acid oil, palm kernel acid oil, Cupriavidus necator.
Effect of relative humidity on the morphology of electrospun polymer fibers
Authors: Medeiros Eliton S , Mattoso Luiz H.C. , Offeman Richard D , Wood Delilah F , Orts William J
Published: May 2008

The effect of relative humidity on the morphology of electrospun fibers of poly(vinyl alcohol), poly(methyl methacrylate), poly(vinyl chloride), polystyrene, and poly(lactic acid) dissolved in solvents such as toluene, N,N-dimethylformamide, 2,2,2-trifluoroethanol, and deionized water was studied by scanning electron microscopy to investigate the factors that may contribute to pore formation. Results showed that the presence of pores depends on factors such as the type of polymers used, the polymer–solvent combination, molecular weight, and the size of the electrospun structure. The final morphology developed implies a competition between the dynamics of phase separation and the rate of solvent evaporation. In addition, continuous solvent evaporation and constant stretching owing to the electric potential difference give rise to the final shape of porous electrospun fibers.Key words: electrospinning, relative humidity, porous fibers, polymers.
Swelling of Valonia cellulose microfibrils in amine oxide systems
Authors: Noé Pierre , Chanzy Henri
Published: May 2008

Cellulose microfibrils from Valonia ventricosa cell-wall fragments were immersed into molten N-methylmorpholine-N-oxide monohydrate (NMMO·H2O), stabilized with n-propyl gallate and kept at 80 °C. The resulting ultrastructural modifications, which were followed by transmission electron microscopy and electron diffraction analysis, showed that within minutes the solvent slowly penetrated inside the crystalline microfibrils and progressed as a wedge in between the cellulose chains without cutting them. Prior to dissolution, a longitudinal subfibrillation of the initial microfibrils occurred, leading to the observation of highly swollen microfibrils, which could reach diameters up to three times larger than those of the initial samples. This mode of swelling is compared with those occurring in other systems, where the intracrystalline swelling of cellulose has been described at the ultrastructural level.Key words: cellulose swelling, Valonia cellulose, N-methylmorpholine-N-oxide.
REDOR recoupling in polymer-stabilized liquid crystals undergoing MAS — Two-dimensional NMR applications with strongly aligned proteins
Authors: Trempe Jean-François , Pomerantseva Ekaterina , Gehring Kalle
Published: May 2008

We recently introduced a technique, termed SAD-REDOR, for recoupling residual dipolar couplings in a single-domain polymer-stabilized liquid crystal (PSLC) undergoing magic-angle spinning (MAS). The experiment was demonstrated with 1H–15N dipolar couplings in a small molecule. Here, we show the applicability of the technique to a strongly aligned protein and we describe a novel two-dimensional experiment to generate in-phase and anti-phase (IPAP) doublets in the 1H dimension of an HSQC NMR spectrum. This pulse sequence, SAD-IPAP, was tested on a sample of 15N-labeled ubiquitin (5 mmol/L) in a polyacrylamide-stabilized Pf1 phage liquid crystal (20 mg/mL). 15N–1H residual dipolar couplings (RDCs) were measured with the SAD-IPAP pulse sequence at spinning speeds of 1000 and 1250 Hz. RDSs were also measured using the conventional HSQC-IPAP method in a sample of 15N-ubiquitin dissolved in a solution of Pf1 phage (1 mg/mL). The resulting RDCs were fitted to the solution structure of ubiquitin to estimate the alignment tensor and to determine the accuracy of the measured couplings. The results highlight the benefits of SAD-REDOR for the measurement of RDCs in strongly aligned macromolecules.Key words: residual dipolar couplings (RDCs), polymer-stabilized liquid crystals (PSLCs), rotational echo double resonance (REDOR) recoupling, magic-angle spinning (MAS), ubiquitin, biomolecular nuclear magnetic resonance (NMR), proteins.
Morphology of a hydrogen-bond mediated self-assembling small molecule in a polycarbonate matrix
Authors: Islam Molla Rafiquel , Sundararajan P R
Published: May 2008

Dispersing functional small molecules in a polymer matrix is a well-known method of device fabrication for optoelectronic applications. Normally, no specific interactions such as hydrogen bonding occur between the polymer and the small molecule. The latter does not belong to the category of “self-assembling” molecules. When phase separation occurs, the small molecule would diffuse to the surface and crystallize. In this paper, we describe a very different morphological behaviour of hydrogen-bond mediated self-assembling molecules in a polycarbonate matrix. We used a series of biscarbamates with two hydrogen-bonding motifs and alkyl side chain lengths symmetrically varying from C4 to C18. We infer that the rate of self-assembly is faster than the diffusion of the small molecule to the surface. As a result, crystallization of the small molecule occurs predominantly in the bulk, i.e., sub surface, and not on the surface of the polymer film.Key words: self-assembly, crystallization, diffusion, phase separation.
Distinctiveness of faces
Authors: Bicego Manuele , Grosso Enrico , Lagorio Andrea , Brelstaff Gavin , Brodo Linda , Tistarelli Massimo
Published: May 2008

This paper develops and demonstrates an original approach to face-image analysis based on identifying distinctive areas of each individual's face by its comparison to others in the population. The method differs from most others—that we refer as
unary
—where salient regions are defined by analyzing only images of the same individual. We extract a set of multiscale patches from each face image before projecting them into a common feature space. The degree of “distinctiveness” of any patch depends on its distance in feature space from patches mapped from other individuals. First a pairwise analysis is developed and then a simple generalization to the multiple-face case is proposed. A perceptual experiment, involving 45 observers, indicates the method to be fairly compatible with how humans mark faces as distinct. A quantitative example of face authentication is also performed in order to show the essential role played by the distinctive information. A comparative analysis shows that performance of our n-ary approach is as good as several contemporary unary, or binary, methods, while tapping a complementary source of information. Furthermore, we show it can also provide a useful degree of illumination invariance.
A tone-mapping operator for road visibility experiments
Authors: Grave Justine , Bremond Roland
Published: May 2008

One may wish to use computer graphic images to carry out road visibility studies. Unfortunately, most display devices still have a limited luminance dynamic range, especially in driving simulators. In this paper, we propose a tone-mapping operator (TMO) to compress the luminance dynamic range while preserving the driver's performance for a visual task relevant for a driving situation. We address three display issues of some consequences for road image display: luminance dynamics, image quantization, and high minimum displayable luminance. Our TMO characterizes the effects of local adaptation with a bandpass decomposition of the image using a Laplacian pyramid, and processes the levels separately in order to mimic the human visual system. The contrast perception model uses the visibility level, a usual index in road visibility engineering applications. To assess our algorithm, a psychophysical experiment devoted to a target detection task was designed. Using a Landolt ring, the visual performances of 30 observers were measured: they stared first at a high-dynamic range image and then at the same image processed by a TMO and displayed on a low-dynamic range monitor, for comparison. The evaluation was completed with a visual appearance evaluation. Our operator gives good performances for three typical road situations (one in daylight and two at night), after comparison with four standard TMOs from the literature. The psychovisual assessment of our TMO is limited to these driving situations.
Optimal probabilistic fingerprint codes
Authors: Tardos Gábor
Published: May 2008

We construct binary codes for fingerprinting digital documents. Our codes for
n
users that are ϵ-secure against
c
pirates have length
O
(
c
2
log(
n
/ϵ)). This improves the codes proposed by Boneh and Shaw [1998] whose length is approximately the square of this length. The improvement carries over to works using the Boneh--Shaw code as a primitive, for example, to the dynamic traitor tracing scheme of Tassa [2005].

By proving matching lower bounds we establish that the length of our codes is best within a constant factor for reasonable error probabilities. This lower bound generalizes the bound found independently by Peikert et al. [2003] that applies to a limited class of codes. Our results also imply that randomized fingerprint codes over a binary alphabet are as powerful as over an arbitrary alphabet and the equal strength of two distinct models for fingerprinting.
Buffer optimization in multitask implementations of Simulink models
Authors: Natale Marco Di , Pappalardo Valerio
Published: May 2008

Automatic generation of a controller implementation from a synchronous reactive model is among the best practices for software development in the automotive and aeronautics industry, because of the possibility of simulation, model checking, and error-free implementation. This paper discusses an algorithm for optimizing the single-processor multitask implementation of Simulink models with real-time execution constraints, derived from the sampling rates of the functional blocks. Existing code generation tools enforce the addition of extra buffering and latencies whenever there is a rate transition among functional blocks. This work shows how timing analysis can be used to find the cases in which additional buffering and latency can be avoided, improving the space and time performance of the application. The proposed search algorithm allows finding a solution with reduced and possibly minimal use of buffering even for very high values of processor utilization.
An energy-aware framework for dynamic software management in mobile computing systems
Authors: Fei Yunsi , Zhong Lin , Jha Niraj K.
Published: May 2008

Energy efficiency has become a very important and challenging issue for resource-constrained mobile computers. In this article, we propose a novel dynamic software management (DSOM) framework to improve battery utilization. We have designed and implemented a DSOM module in user space, independent of the operating system (OS), which explores quality-of-service (QoS) adaptation to reduce system energy and employs a priority-based preemption policy for multiple applications to avoid competition for limited energy resources. Software energy macromodels for mobile applications are employed to predict energy demand at each QoS level, so that the DSOM module is able to select the best possible trade-off between energy conservation and application QoS; it also honors the priority desired by the user. Our experimental results for some mobile applications (video player, speech recognizer, voice-over-IP) show that this approach can meet user-specified task-oriented goals and significantly improve battery utilization.
Design and optimization of distributed sensing coverage in wireless sensor networks
Authors: Yan Ting , Gu Yu , He Tian , Stankovic John A.
Published: May 2008

For many sensor network applications, such as military surveillance, it is necessary to provide full sensing coverage to a security-sensitive area while, at the same time, minimizing energy consumption and extending system lifetime by leveraging the redundant deployment of sensor nodes. In this paper, we propose a surveillance service for sensor networks based on a distributed energy-efficient sensing coverage protocol. In the protocol, each node is able to dynamically decide a schedule for itself to guarantee a certain degree-of-coverage (DOC) with average energy consumption inversely proportional to the node density. Several optimizations and extensions are proposed to enhance the basic design with a better load-balance feature and a longer network lifetime. We consider and address the impact of the target size and the unbalanced initial energy capacity of individual nodes to the network lifetime. Several practical issues such as the localization error, irregular sensing range, and unreliable communication links are addressed as well. Simulation shows that our protocol extends system lift-time significantly with low energy consumption. It outperforms other state-of-the-art schemes by as much as 50% reduction in energy consumption and as much as 130% increase in the half-life of the network.