bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micro‐zircon: origin and evolution during metamorphism
Authors: DEMPSTER T. J. , HAY D. C. , GORDON S. H. , KELLY N. M. 
Published: April 2008

AbstractThe size and distribution of zircon within a garnet‐mica‐schist from the Scottish Highlands were assessed using scanning electron microscopy. The study reveals that abundant 0.2–3.0 μm sized zircon is preferentially concentrated within garnet and biotite porphyroblasts. The micro‐zircon has grown during regional metamorphism and represents >90% of the total number of zircon in the schist. It is texturally distinct from a few larger detrital zircon grains in the schist that commonly preserve evidence of dissolution, and more rarely, small metamorphic outgrowths. The sequential incorporation of zircon in porphyroblasts allows prograde changes in the morphology of the zircon population to be identified. Zircon is reactive and soluble, and responds to medium‐grade metamorphism in a series of dissolution and crystallization events, linked to possible changes in fluid composition. Deformation also has a significant influence on the distribution of zircon, allowing inclusions previously trapped within biotite to react. About 8 × 106 micro‐zircon occur as inclusions within a typical individual 5‐mm garnet porphyroblast and their presence must be considered prior to trace‐element or isotopic analysis of such metamorphic phases.
Telomere length and obesity
Authors: Zannolli Raffaella , Mohn Angelika , Buoni Sabrina , Pietrobelli Angelo , Messina Mario , Chiarelli Francesco , Miracco Clelia 
Published: April 2008

AbstractAim: To assess the telomere length in apparently healthy obese and normal‐weight subjects.Methods: Seventy‐six Caucasian subjects were chosen including 53 children (age 8.2 ± 3.5 years) and 23 adults (age 40.5 ± 8.4 years). Among these, 22 (12 children and 10 adults) were obese with a body mass index (BMI, kg/m2) > 2 SD above the norm. Bioelectrical impedance analysis (BIA), measured with a multiple frequency analyzer, was used to estimate body composition. DNA extraction from white blood cells was used to estimate the telomere length by detection of terminal restriction fragments (TRF).Results: No difference was found between the TRF lengths of obese and normal children. Obese adults had shorter TRF lengths than adults who were not obese (mean TRF length difference, −884.5; 95% confidence intervals −1727 to −41.8; t= 2.183; df = 17; p < 0.041).Conclusions: Obese adults have shorter telomeres than their normal‐weight counterparts, while this phenomenon is not present in childhood.
Blocking of Bacterial Biofilm Formation by a Fish Protein Coating
Authors: Vejborg Rebecca Munk , Klemm Per 
Published: April 2008

ABSTRACT
Bacterial biofilm formation on inert surfaces is a significant health and economic problem in a wide range of environmental, industrial, and medical areas. Bacterial adhesion is generally a prerequisite for this colonization process and, thus, represents an attractive target for the development of biofilm-preventive measures. We have previously found that the preconditioning of several different inert materials with an aqueous fish muscle extract, composed primarily of fish muscle α-tropomyosin, significantly discourages bacterial attachment and adhesion to these surfaces. Here, this proteinaceous coating is characterized with regards to its biofilm-reducing properties by using a range of urinary tract infectious isolates with various pathogenic and adhesive properties. The antiadhesive coating significantly reduced or delayed biofilm formation by all these isolates under every condition examined. The biofilm-reducing activity did, however, vary depending on the substratum physicochemical characteristics and the environmental conditions studied. These data illustrate the importance of protein conditioning layers with respect to bacterial biofilm formation and suggest that antiadhesive proteins may offer an attractive measure for reducing or delaying biofilm-associated infections.
Longitudinal Study of Antimicrobial Resistance among
Escherichia coli
Isolates from Integrated Multisite Cohorts of Humans and Swine
Authors: Alali W. Q. , Scott H. M. , Harvey R. B. , Norby B. , Lawhorn D. B. , Pillai S. D. 
Published: April 2008

ABSTRACT

In a 3-year longitudinal study, we examined the relationship between the seasonal prevalence of antimicrobial-resistant (AR)
Escherichia coli
isolates from human wastewater and swine fecal samples and the following risk factors: the host species, the production type (swine), the vocation (human swine workers, non-swine workers, and slaughter plant workers), and the season, in a multisite, vertically integrated swine and human population representative of a closed agri-food system. Human and swine
E. coli
(
n
= 4,048 and 3,429, respectively) isolates from wastewater and fecal samples were tested for antimicrobial susceptibility, using the Sensititre broth microdilution system. There were significant (
P
< 0.05) differences among AR
E. coli
prevalence levels of (i) the host species, in which swine isolates were at higher risk for resistance to tetracycline, kanamycin, ceftiofur, gentamicin, streptomycin, chloramphenicol, sulfisoxazole, and ampicillin; (ii) the swine production group, in which purchased boars, nursery piglets, and breeding boars isolates had a higher risk of resistance to streptomycin and tetracycline; and iii) the vocation cohorts, in which swine worker cohort isolates exhibited lower sulfisoxazole and cefoxitin prevalence than the non-swine worker cohorts, while the slaughter plant worker cohort isolates exhibited elevated cefoxitin prevalence compared to that of non-swine workers. While a high variability was observed among seasonal samples over the 3-year period, no significant temporal trends were apparent. There were significant differences in the prevalence levels of multidrug-resistant isolates between host species, with swine at a higher risk of carrying multidrug-resistant strains than humans. Considering vocation, slaughter plant workers were at higher risk of exhibiting multidrug-resistant
E. coli
than non-swine workers.
Glucosamine Found as a Substituent of Both Phosphate Groups inBordetellaLipid A Backbones: Role of a BvgAS-Activated ArnT Ortholog
Authors: Marr Nico , Tirsoaga Alina , Blanot Didier , Fernandez Rachel , Caroff Martine 
Published: April 2008

ABSTRACTEndotoxins are amphipathic lipopolysaccharides (LPSs), major constituents of the outer membrane of gram-negative bacteria. They consist of a lipid region, covalently linked to a core oligosaccharide, to which may be linked a repetitive glycosidic chain carrying antigenic determinants. Most of the biological activities of endotoxins have been associated with the lipid moiety of the molecule: unique to gram-negative bacteria, LPS is a ligand of the mammalian TLR4-MD2-CD14 pathogen recognition receptor complex. Lipid A preparations are often heterogeneous with respect to both the numbers and the lengths of fatty acids and the natures of substituents on the phosphate groups when present. The variants can significantly affect host immune responses. Nine species in theBordetellagenus have been described, and the fine LPS structures of seven of them have been published. In this report, lipids A fromBordetella pertussisTohama I andB. bronchisepticastrain 4650 were further characterized and revealed to have a glucosamine substituting both lipid A phosphate groups of the diglucosamine backbone. These substitutions have not been previously described for bordetellae. Moreover, aB. pertussistransposon mutation that maps within a gene encoding aBordetellaArnT (formerly PmrK) glycosyl transferase ortholog does not carry this substitution, thus providing a genetic basis for the modification. Reverse transcriptase PCR of this locus showed that it is Bvg regulated, suggesting that the ability ofBordetellato modify lipid A via this glucosamine modification is a potential virulence trait.
Model for the prediction of shear strength with respect to soil suction
Authors: Vanapalli S K , Fredlund D G , Pufahl D E , Clifton A W 
Published: April 2008

Experimental studies on unsaturated soils are generally costly, time-consuming, and difficult to conduct. Shear strength data from the research literature suggests that there is a nonlinear increase in strength as the soil desaturates as a result of an increase in matric suction. Since the shear strength of an unsaturated soil is strongly related to the amount of water in the voids of the soil, and therefore to matric suction, it is postulated that the shear strength of an unsaturated soil should also bear a relationship to the soil-water characteristic curve. This paper describes the relationship between the soil-water characteristic curve and the shear strength of an unsaturated soil with respect to matric suction. Am empirical, analytical model is developed to predict the shear strength in terms of soil suction. The formulation makes use of the soil-water characteristic curve and the saturated shear strength parameters. The results of the model developed for predicting the shear strength are compared with experimental results for a glacial till. The shear strength of statically compacted glacial till specimens was measured using a modified direct shear apparatus. Specimens were prepared at three different water contents and densities (i.e., corresponding to dry of optimum, and wet of optimum conditions). Various net normal stresses and matric suctions were applied to the specimens. There is a good correlation between the predicted and measured values of shear strength for the unsaturated soil. Key words: soil-water characteristic curve, shear strength, unsaturated soil, soil suction, matric suction.
Pipesoil interaction analysis of jointed water mains
Authors: Rajani B , Zhan C , Kuraoka S 
Published: April 2008

Water mains are important lifelines of modern urban infrastructure. However, in most developed countries, the average life of these cast or ductile iron pipes approaches 5075 years. In recent years, the disruption of water sevices as a consequence of water main breaks is on the rise in most Cadadian cities. This paper describes the developement of a simplified Winkler model to stimulate the responses of a jointed water main subjected to differential temperature change and water pressure. The simplified Winkler model accounts for axial and radial restraints offered by the surronding soil. In spite of its simplicity, the Winkler model is able to predict the overall response of strains and stresses, which confirms satisfactorily some of heuristic and documented observations on water main breaks. Key words: water main breaks, pipesoil interaction, temperature influence, Winkler model.
Effects of stress and temperature on secondary compression of peat
Authors: Fox Patrick J , Edil Tuncer B 
Published: April 2008

Results from field and laboratory tests illustrate the influence of vertical effective stress and temperature on the secondary compression of peat from Middleton, Wisconsin, U.S.A. A large fraction of the total settlement of the peat is due to secondary compression. The coefficient of secondary compression, Calpha, generally increases with time, and settlement predictions using a constant Calpha may underestimate field settlement. Laboratory step-stress and step-temperature tests indicate that the rate of void ratio change during secondary compression varies exponentially with both temperature and vertical effective stress. A stress coefficient of creep, Ctheta, and a temperature coefficient of creep, CT, are defined to characterize these relationships. For Middleton peat, the logarithm of Ctheta decreases linearly with void ratio and CT is constant. The results suggest that laboratory stress and temperature conditions should match those in situ for accurate determination of secondary compression parameters. Cooling also has an important effect on the secondary compression of peat. For large decreases in temperature, an overconsolidated condition is created for which additional secondary compression is greatly reduced. Settlement data from two test embankments on peat illustrate the effect of staged construction and subsurface heating on secondary compression in the field. The temperature changes achieved in situ were not large enough to cause a strong thermal precompression effect. Key words: peat, organic soil, secondary compression, consolidation, settlement.
Contaminant transport through a soil liner underlain by an unsaturated stone collection layer
Authors: Badv K , Rowe R Kerry 
Published: April 2008

Chloride and sodium migration in an unsaturated stone collection system underlying a compacted soil liner was examined for three different flow rates ranging between 2.5 and 0.017 m/a. Relatively high and uniform concentrations were observed in the unsaturated stone layer. The groundwater velocity played a significant role in contaminant transport through unsaturated stone even at a flow of 0.017 m/a. Experimental observations were accurately predicted using one-dimensional advectivediffusivedispersive theory. Transport parameters were reduced by modelling the test data. Key words: soil liner, unsaturated flow, diffusion, landfill, collection system.
Rock instability and risk analyses in open stope mine design
Authors: Diederichs Mark S , Kaiser Peter K 
Published: April 2008

Modern underground mining methods often call for the excavation of large, often unsupported voids called stopes. In many cases, these are nonentry stopes, with the removal of broken rock (mucking) performed by remote control. With the risk to human safety thus reduced, stability concerns within the stopes are primarily driven by the economics of unplanned overbreak and waste rock dilution of the mined ore. In this context, it is appropriate to speak of acceptable risks of instability and to optimize design by balancing risk costes with productivity potential. Larger individual stopes generally increase productivity while reducing stability. The modified stability graph is a popular empirical mine design tool that has been calibrated to provide discrete recommendations for maximum stope dimensions based on a rock quality index. It seems appropriate to extend the method to account for variability in the calibration data and also for variability in each new set of input parameters. A risk template and associated probabilistic techniques are proposed to supplement the discrete design limits currently established. Key words: risk, mining, stability, design, emperical.
The relationship of the unsaturated soil shear strength to the soil-water characteristic curve
Authors: Fredlund D G , Xing Anqing , Fredlund M D , Barbour S L 
Published: April 2008

The measurement of soil parameters, such as the permeability and shear strength functions, used to describe unsaturate soil behaviour can be expensive, difficult, and often impractical to obtain. This paper proposes a model for predicting the shear strength (versus matric suction) function of unsaturated soils. The prediction model uses the soil-water characteristic curve and the shear strength parameters of the saturated soil (i.e., effective cohesion and effective angle of internal friction). Once a reasonable estimate of the soil-water characteristic curve is obtained, satisfactory predictions of the shear strength function can be made for the unsaturated soil. Closed-form solutions for the shear strength function of unsaturated soils are obtained for cases where a simple soil-water characteristic equation is used in the prediction model. Key words: soil suction, soil-water characteristic curve, shear strength function, unsaturated soil.
Stress-dependent flow through fractured clay till: a laboratory study
Authors: Sims John E , Elsworth Derek , Cherry John A 
Published: April 2008

Stress-dependent hydraulic conductivities of weathered fractured clay till were measured in a flexible-wall permeameter. Measured conductivities were in the range 107 to 108 cm/s, of the same order as the clay matrix (108 cm/s), and representing equivalent hydraulic apertures in the range 05 μm. In general, the isolated fractures exhibited strongly nonlinear closure characteristics and hysteric behaviour under stress reversal. Some fracture samples exhibited only weak stress dependency, representing observable features of only nominal conductivity. Results of the investigations suggest fractures are closed to residuel aperture for an overburden load of the order of 12 m, this defining an effective closure depth and the degree of maximum useful compactive effort that might be applied to "seal" fractures and reduce fluid migration. Key words: fracture permeability, till, stress permeability, landfills.
Hydraulic conductivity of homogenized tailings from hard rock mines
Authors: Aubertin Michel , Bussiere Bruno , Chapuis Robert P 
Published: April 2008

Tailings produced by milling for one extraction from hard rock mines, which range in size from clay to fine sand, have relatively low hydraulic conductivity, k. The value of k must be known with a certain degree of certainty to analyze consolidation and seepage conditions in and around tailings ponds. In this paper, the authors present the results of a laboratory investigation on hydraulic conductivity of homogenized tailings from hard rock mines. After describing some of the basic properties of four different materials, including mineralogy, grain size, Atterberg limits, compaction characteristics, and consolidation curves, permeability test results are given. The hydraulic conductivity value usually varies between 104 and 105 cm/s. The effect of various factors on this value, including void ratio and grain size, is then discussed in relation to predictive models. It is shown that a modified version of the Kozeny-Carman equation, in which a tortuosity factor and a grain-size distribution function are included explicitly, can represent the data very well. The equation is also checked against results taken from the literature on similar types of materials. Key words: tailings, hydraulic conductivity, laboratory tests, void ratio, grain size, tortuosity.
Statistical relationships between piezocone measurements and stress history of clays
Authors: Chen B SY , Mayne P W 
Published: April 2008

A database containing piezocone soundings from 205 clay sites around the world has been compiled for the calibration of an analytical cone penetration model and the development of statistical correlations. Yield stresses from laboratory oedometer tests were used as reference values for determining the stress history of natural clay deposits. Both simple and multiple regression analyses were performed on these data to evaluate correlative trends. Several simplified empirical relationships were identified for use in practice with the most reliable in relating preconsolidation stress to net cone tip resistance. Key words: cone tip resistance, overconsolidation ratio (OCR), preconsolidation pressure, piezocone, statistical relationships, stress history.
A capillary flow meter for measuring the hydraulic conductivity of clay under low gradients
Authors: Ranjan R Sri , Karthigesu T 
Published: April 2008

The measurement of water flow through clay at low hydraulic gradients (<1) is a very difficult task requiring several months to accomplish in a laboratory. A capillary flow meter, capable of measuring extremely low flow rates through clay samples under low imposed hydraulic gradients, has been designed and tested. Flux as low as 1012 m·s1 was successfully measured using this flow meter. To minimize the contaminatiion effects, perchloroethylene, which has self-cleaning ability, mixed with Sudan IV was used as the bubble liquid in the capillary flow meter. Glass and Teflon® valves were fused to the inflow and outflow capillary tubes to permit these components to be flushed with cleaning agents and distilled water. The movement of the menisci through the capillary tube was used as a measure of the volume flow rate through the sample. A sensitive differential pressure transducer was connected between the inflow and outflow end of the clay sample to measure the imposed hydraulic head difference. This flow meter has been independently calibrated against a conventional constant head permeameter. Once the clay samples have stabilized in a permeameter, oedometer, or a triaxial cell, multiple flow measurements under low hydraulic gradients can be done in less than an hour. Key words: nonlinear flow, saturated hydraulic conductivity, non-Darcy flow, ultra-low flow meter.
Shear moduli and damping in frozen and unfrozen clay by resonant column tests
Authors: Al-Hunaidi M O , Chen P A , Rainer J H , Tremblay M 
Published: April 2008

The resonant-column test method was used in this study to determine the dynamic shear moduli and damping ratios of frozen and unfrozen soil samples. Naturally frozen soil specimens were obtained in-situ during the winter. A series of tests were carried out on the frozen soil specimens in a cold room at 9°C. The same specimens, after allowing them to thaw, were then tested at room temperature. Test results show that at low-amplitude shear stains the damping ratio of frozen soil specimens is roughly twice that of unfrozen samples. In addition, the dynamic shear modulus for soil specimens while frozen is significantly greater (30 or 50 times) than that of unfrozen specimens. These results provide a basis for explaining an observation that bus-induced vibrations in buildings while the top soil is frozen in winter are about one-half those induced while the soil is not frozen. Key words: resonant-column test, shear modulus, damping ratio, frozen soil, ground vibration.
SOFTWARE EFFORT ESTIMATION BY ANALOGY USING ATTRIBUTE SELECTION BASED ON ROUGH SET ANALYSIS
Authors: LI JINGZHOU , RUHE GUENTHER 
Published: April 2008

Estimation by analogy (EBA) predicts effort for a new project by learning from the performance of former projects. This is done by aggregating effort information of similar projects from a given historical data set that contains projects, or objects in general, and attributes describing the objects. While this has been successful in general, existing research results have shown that a carefully selected subset, as well as weighting, of the attributes may improve the performance of the estimation methods.In order to improve the estimation accuracy of our former proposed EBA method AQUA, which supports data sets that have non-quantitative and missing values, an attribute weighting method using rough set analysis is proposed in this paper. AQUA is thus extended to AQUA+by incorporating the proposed attribute weighting and selection method. Better prediction accuracy was obtained by AQUA+compared to AQUA for five data sets. The proposed method for attribute weighting and selection is effective in that (1) it supports data sets that have non-quantitative and missing values; (2) it supports attribute selection as well as weighting, which are not supported simultaneously by other attribute selection methods; and (3) it helps AQUA+to produce better performance.