bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethylene synthesis inhibition effects on oxidative stress and in vitro conservation of Lippia filifolia (Verbenaceae)
Authors: Pimenta MR. , Ribeiro C. , Soares CQG. , Mendes GC. , Braga VF. , Reis LB. , Otoni WC. , Resende CF. , Viccini LF. , Peixoto PHP.
Published: November 2013

This study aimed to investigate the effects of ethylene biosynthesis inhibitors on oxidative metabolisms and the in vitro conservation of Lippia filifolia, using the lipid peroxidation index (TBARS), antioxidative enzymes and pigments as biomarkers. We found that EDTA, sodium thiosulfate (STS) and especially Co had protective effects on oxidative stress in tissues cultured in vitro, resulting in a delay of the senescence and the reduction of subcultures frequency, con-tributing to the germplasm conservation of this species.
Influence of loading rate on failure mode of reinforced concrete members
Authors: Isaac Philip , Darby Antony , Ibell Tim , Evernden Mark
Published: November 2013

The lack of simplified methods for accurately predicting the response mode of reinforced concrete structural members (predominantly beams and columns) to impulsive loads indicates a lack of fundamental understanding of the complicated response of members in this situation. This often leads to engineers using over-simplified analytical methods or developing complex finite-element models, the reliability of which has been questioned. This paper presents the development of a theoretical model for predicting the initial demand on a reinforced concrete member subjected to impulsive loads, which can be used to show whether a brittle shear failure results. The model treats the response as being dominated by a wave phenomenon and employing a time increment approach to solve the equation of motion. Under impact loading, the model is able to demonstrate why higher velocity impacts are more likely to cause brittle shear failures in reinforced concrete beams than slower ones for the same impact energy. The paper concludes by extending the proposed method to predict the shear and bending demands on a blast-loaded member. It is hoped that through this new analytical model, design guidelines for new structures can be improved and better assessments of the vulnerability of existing structures can be carried out.
Passive accuracy adjustment of membrane reflectors
Authors: Jiang Jie , Li Tuan-Jie
Published: November 2013

Based on the temperature changes in space, this paper presents an innovative method of passive accuracy adjustment for large membrane reflectors. Flexible patches with different coefficients of thermal expansion (CTEs) from that of the reflector material are pasted on to the reverse side of the membrane reflector. The patches and membrane reflector will experience different thermal deformation when the temperature changes in space, which allows surface accuracy adjustment. A finite-element analysis model of membrane reflector and patches is established and a static equilibrium equation of the membrane reflector system is derived. The paper also puts forward a thermal deformation influence coefficient matrix and proposes an optimisation model for surface accuracy adjustment. The coefficient of thermal expansion of each flexible patch is derived using a least-squares approach to optimise the objective function. The analysis of patch arrangement is discussed according to the surface accuracy influence coefficient matrix. The results of numerical examples under uniform temperature and a gradient temperature distribution show that passive adjustment of the surface accuracy of membrane reflectors is effective and the arrangement method of the flexible patches is feasible.
Multi‐trophic resilience of boreal lake ecosystems to forest fires
Authors: Lewis Tyler L. , Lindberg Mark S. , Schmutz Joel A. , Bertram Mark R.
Published: November 2013

Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before‐after‐control‐impact (BACI) design, with pre‐ and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll a levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire‐mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.
Landscape genetic connectivity in a riparian foundation tree is jointly driven by climatic gradients and river networks
Authors: Cushman Samuel A. , Max Tamara , Meneses Nashelly , Evans Luke M. , Ferrier Sharon , Honchak Barbara , Whitham Thomas G. , Allan Gerard J.
Published: November 2013

Fremont cottonwood (Populus fremonti) is a foundation riparian tree species that drives community structure and ecosystem processes in southwestern U.S. ecosystems. Despite its ecological importance, little is known about the ecological and environmental processes that shape its genetic diversity, structure, and landscape connectivity. Here, we combined molecular analyses of 82 populations including 1312 individual trees dispersed over the species' geographical distribution. We reduced the data set to 40 populations and 743 individuals to eliminate admixture with a sibling species, and used multivariate restricted optimization and reciprocal causal modeling to evaluate the effects of river network connectivity and climatic gradients on gene flow. Our results confirmed the following: First, gene flow of Fremont cottonwood is jointly controlled by the connectivity of the river network and gradients of seasonal precipitation. Second, gene flow is facilitated by mid‐sized to large rivers, and is resisted by small streams and terrestrial uplands, with resistance to gene flow decreasing with river size. Third, genetic differentiation increases with cumulative differences in winter and spring precipitation. Our results suggest that ongoing fragmentation of riparian habitats will lead to a loss of landscape‐level genetic connectivity, leading to increased inbreeding and the concomitant loss of genetic diversity in a foundation species. These genetic effects will cascade to a much larger community of organisms, some of which are threatened and endangered.
Implementation of CFD modeling in the performance assessment and optimization of secondary clarifiers: the PVSC case study
Authors: Xanthos S. , Ramalingam K. , Lipke S. , McKenna B. , Fillos J.
Published: November 2013

The water industry and especially the wastewater treatment sector has come under steadily increasing pressure to optimize their existing and new facilities to meet their discharge limits and reduce overall cost. Gravity separation of solids, producing clarified overflow and thickened solids underflow has long been one of the principal separation processes used in treating secondary effluent. Final settling tanks (FSTs) are a central link in the treatment process and often times act as the limiting step to the maximum solids handling capacity when high throughput requirements need to be met. The Passaic Valley Sewerage Commission (PVSC) is interested in using a computational fluid dynamics (CFD) modeling approach to explore any further FST retrofit alternatives to sustain significantly higher plant influent flows, especially under wet weather conditions. In detail there is an interest in modifying and/or upgrading/optimizing the existing FSTs to handle flows in the range of 280–720 million gallons per day (MGD) (12.25–31.55 m3/s) in compliance with the plant's effluent discharge limits for total suspended solids (TSS). The CFD model development for this specific plant will be discussed, 2D and 3D simulation results will be presented and initial results of a sensitivity study between two FST effluent weir structure designs will be reviewed at a flow of 550 MGD (∼24 m3/s) and 1,800 mg/L MLSS (mixed liquor suspended solids). The latter will provide useful information in determining whether the existing retrofit of one of the FSTs would enable compliance under wet weather conditions and warrants further consideration for implementing it in the remaining FSTs.
Influence of air flow rate and backwashing on the hydraulic behaviour of a submerged filter
Authors: Cobos-Becerra Yazmin Lucero , González-Martínez Simón
Published: November 2013

The aim of this study was to evaluate backwashing effects on the apparent porosity of the filter media and on the hydraulic behaviour of a pilot scale submerged filter, prior to biofilm colonization, under different hydraulic retention times, and different air flow rates. Tracer curves were analysed with two mathematical models for ideal and non-ideal flow (axial dispersion and Wolf and Resnick models). The filter media was lava stones sieved to 4.5 mm. Backwashing causes attrition of media particles, decreasing the void volume of the filter media and, consequently, the tracer flow is more uniform. The eroded media presented lower dead volumes (79% for the filter with aeration and 8% for the filter without aeration) compared with the new media (83% for the filter with aeration and 22% for the filter without aeration). The flow patterns of eroded and new media were different because the more regular shape of the particles decreases the void volume of the filter media. The dead volume is attributed, in the case of the filter with aeration, to the turbulence caused by the air bubbles that generate preferential channelling of the bulk liquid along the filter media, creating large zones of stagnant liquid and, for the filter without aeration, to the channels formed due to the irregular shaped media.
Performance of activated sludge diffusion for biological treatment of hydrogen sulphide gas emissions
Authors: Barbosa Vera L. , Stuetz Richard M.
Published: November 2013

Odours from wastewater treatment plants are comprised of a mixture of various gases with hydrogen sulphide (H2S) often being the dominant constituent. Activated sludge diffusion (ASD) as a biotreatment system for odour abatement has been conducted for over 30 years but has limited broad application due to disagreement in the literature regarding the effect that ASD may have on wastewater treatment performance. The effects of continuous H2S diffusion at 25 ppmv, with weekly peaks of approximately 100 ppmv, on H2S removal efficiency and wastewater treatment performance was evaluated over a 2-month period using an activated sludge pilot plant. H2S removal averaged 100% during diffusion at 25 ppmv, and 98.9% during the 100 ppmv peak periods. A significant increase in mixed liquor volatile suspended solids concentration (P < 0.01) was observed during H2S diffusion, which may be due to an increase in H2S-degrading microorganisms. There was no adverse effect of H2S on nitrification throughout the ASD trials. Ammonia (NH3) removal was slightly better in the test receiving H2S diffusion (87.6%) than in the control (85.4%). H2S diffusion appeared to improve robustness of the AS biomass to operational upsets.
The effects of electrode spacing on the performance of microbial fuel cells under different substrate concentrations
Authors: Lee Chi-Yuan , Huang Ya-Ni
Published: November 2013

In this study, the electricity generation and organic removal in microbial fuel cells (MFCs) were examined for electrode spacing (ES) covering 5.8, 10.2, 15.1, and 19.5 cm, and for each ES the MFCs were discharged with a series of influent substrates (CODin). Results indicate that organic removal was related to CODin but not to ES. Best chemical oxygen demand (COD) removals of 64–71% could be achieved at CODin around 100 mg COD/L (0.11–0.14 kg COD/m3-day). Best power output 3.32 mW/m2 occurred at ES 5.8 cm and nominal CODin 300 mg COD/L. For every ES, the relationship of electricity generation to local substrate near anode (CODad) could be adequately modeled by Monod-type kinetics. The estimated kinetic constants involve maximum current production, Imax, 15.3–19.6 mA/m2; maximum attainable power output, Pp,max, 4.0–2.5 mW/m2; half-saturation constant of current, Ksi, 22–30 mg COD/L; and half-saturation constant of power, Ksp, 24–90 mg COD/L. This study reveals that the control over ES for improving electricity generation is dependent on the level of CODad, which profoundly affects the optimal design of electrode placement.
Chemical and toxicological evaluation of transformation products during advanced oxidation processes
Authors: vom Eyser C. , Börgers A. , Richard J. , Dopp E. , Janzen N. , Bester K. , Tuerk J.
Published: November 2013

The entry of pharmaceuticals into the water cycle from sewage treatment plants is of growing concern because environmental effects are evident at trace levels. Ozonation, UV- and UV/H2O2-treatment were tested as an additional step in waste water treatment because they have been proven to be effective in eliminating aqueous organic contaminants. The pharmaceuticals carbamazepine, ciprofloxacin, diclofenac, metoprolol and sulfamethoxazole as well as the personal care products galaxolide and tonalide were investigated in terms of degradation efficiency and by-product formation in consideration of toxic effects. The substances were largely removed from treatment plant effluent by ozonation, UV- and UV/H2O2-treatment. Transformation products were detected in all tested treatment processes. Accompanying analysis showed no genotoxic, cytotoxic or estrogenic potential for the investigated compounds after oxidative treatment of real waste waters. The results indicate that by-product formation from ozonation and advanced oxidation processes does not have any negative environmental impact.
Experimental evaluation of the nitrite sensitivity coefficient in granular anammox biomass
Authors: Rosenthal A. , Ramalingam K. , Beckmann K. , Deur A. , Fillos J.
Published: November 2013

Nitrite is widely reported to inhibit anammox activity and growth. One modeling approach for nitrite impairment of anammox growth is the use of a nitrite sensitivity coefficient which increases the endogenous decay coefficient of anammox bacteria proportionally to nitrite concentration. The objective of this study was to measure nitrite concentration profiles within active anammox granules incubated at fixed bulk nitrite concentrations and to compare these with nitrite concentration profiles predicted by a biofilm model that incorporates the nitrite sensitivity coefficient. We developed an apparatus for the repeated measurement of nitrite concentration profiles along the radius of granular anammox biomass over a period of 6 days at fixed bulk nitrite concentrations. Granular anammox biomass was obtained from a two-stage bench-scale partial nitritation/anammox reactor system. There was no apparent effect of nitrite concentration on nitrite utilization kinetics after 6 days at exposures up to 90 mg NO2−-N/L. These findings suggest that anammox bacteria tolerate extended exposures to elevated nitrite concentrations, and in its present form, the nitrite sensitivity coefficient is not applicable for anammox growth modeling.
Bejan’s Constructal theory and overall performance assessment: The global optimization for heat exchanging finned modules
Authors: Lorenzini Giulio , Moretti Simone
Published: November 2013

Bejan's Constructal theory has provided a dramatic contribution to the design
of natural and industrial systems, mainly because all sort of flows tend to
follow precise rules which Bejan was able to explain. Recently, for what
concern heat removal systems, the Authors have extended the classical
Constructal optimization to a broad range of 3-D geometries, also applying
such results to the optimal choice of the suitable thermal carrier fluid. The
definition of the Global Optimization was centred on the concepts of
Relevance and Overall Performance Coefficient, which are technical
parameters. This paper follows the principle of Constructal theory in the
assessment of the Global Optimization to highlight how the coupling of the
two may provide a tool becoming part of everyday decision making processes in
future design. The results show not only which is the best performing module
but also proves that, via the superimposition of a suitable Relevance value,
the Overall Performance Coefficient allows for the correct characterization
of the whole heat transfer process, so confirming the interesting perspective
of the novel approach proposed.
Resident Macrophages Mediate Islet Amyloid Polypeptide–Induced Islet IL-1β Production and β-Cell Dysfunction
Authors: Westwell-Roper Clara Y. , Ehses Jan A. , Verchere C. Bruce
Published: November 2013

Islet amyloid polypeptide (IAPP) aggregates to form amyloid fibrils in patients with type 2 diabetes and acts as a potent stimulus for interleukin (IL)-1β secretion by bone marrow–derived macrophages. We sought to determine the contribution of resident islet macrophages to IAPP-induced inflammation and β-cell dysfunction. In cultured islets, macrophages (F4/80+CD11b+CD11c+ cells) were required for IAPP-induced mRNA expression of the proinflammatory cytokines IL-1β, tumor necrosis factor-α, and IL-6 and the anti-inflammatory cytokines IL-10 and IL-1 receptor antagonist. Moreover, IAPP-induced IL-1β synthesis and caspase-1 activation were detected in macrophages but not other islet cell types. Transgenic mice with β-cell human IAPP (hIAPP) expression had impaired glucose tolerance, elevated islet Il1b mRNA, and decreased Il10 and Il1rn expression following high-fat feeding. Islet macrophages were the major source of these transcripts and expressed increased cell surface Ly6C and CD11c in hIAPP transgenic mice. Clodronate liposome–mediated depletion of islet macrophages improved glucose tolerance and blocked proinflammatory gene expression in hIAPP-expressing mice, despite increasing the amount of islet amyloid. These data provide the first evidence that IAPP aggregates skew resident islet macrophages toward a proinflammatory phenotype and suggest a mechanism by which anti-inflammatory therapies may protect β-cells from IAPP-induced islet dysfunction.
Elastic Tie-Pointing—Transferring Chronologies between Records via a Gaussian Process
Authors: Heaton Timothy J , Bard Edouard , Hughen Konrad A
Published: November 2013

We consider a general methodology for the transferral of chronologies from a master reference record containing direct dating information to an undated record of interest that does not. Transferral is achieved through the identification, by an expert, of a series of tie-points within both records that are believed to correspond to approximately contemporaneous events. Through tying of the 2 records together at these points, the reference chronology is elastically deformed onto the undated record. The method consists of 3 steps: creation of an age-depth model for the reference record using its direct dating information; selection of the tie-points and translation of their age estimates from the reference to the undated record; and finally, creation of an age-depth model for the undated record using these uncertain tie-point age estimates. Our method takes full account of the uncertainties involved in all stages of the process to create a final chronology within the undated record that allows joint age estimates to be found together with their credible intervals. To achieve computational practicality, we employ a Gaussian process to create our age-depth models. Calculations can then be performed exactly without resort to extremely slow Monte Carlo methods involving multiple independent model fits that would be required by other age-depth models.
CPT symmetry in honeycomb lattices and quantum brachistochrone problem
Authors: Yeşiltaş Özlem
Published: November 2013

In this paper, we have provided a matrix Hamiltonian model for honeycomb lattices and subsequently obtained the dispersion relation. Furthermore, we have constructed the C operator for the given non-Hermitian Hamiltonian model. The quadratic surfaces are sketched and the quantum Brachistochrone problem is discussed for the given honeycomb lattice model.
An Investigation of the Relations Between School Concentrations of Student Risk Factors and Student Educational Well-Being
Authors: Fantuzzo John W. , LeBoeuf Whitney A. , Rouse Heather L.
Published: November 2013

This study investigated the unique relations between school concentrations of student risk factors and measures of reading, mathematics, and attendance. It used an integrated administrative data system to create a combined data set of risks (i.e., birth risks, teen mother, low maternal education, homelessness, maltreatment, and lead exposure) for an entire cohort of third-grade students in a large urban school district. At the school level, high concentrations of children with low maternal education, inadequate prenatal care, homelessness, and maltreatment were most significantly detrimental for student educational well-being. When concentrations of risks at the school level were considered simultaneously with race and poverty, the concentration of poverty was no longer significantly related to targeted educational well-being indicators. For reading achievement and attendance, concentrations of both poverty and race were not significant. Implications for school accountability and community collaborations are discussed.
Learning to Think Critically
Authors: Bowen Daniel H. , Greene Jay P. , Kisida Brian
Published: November 2013

This article examines whether exposure to the arts has an effect on the ability of students to engage in critical thinking. We conduct a randomized controlled trial involving 3,811 students who were assigned by lottery to participate in a School Visit Program at the newly opened Crystal Bridges Museum of American Art. Students who participated in the School Visit Program demonstrated significantly stronger critical thinking skills when analyzing a new painting. These effects were larger for students from more disadvantaged backgrounds. In light of recent declines in the availability of the arts for disadvantaged populations, our results have important policy implications for efforts to restore and expand access to the arts.
Students as Teachers in an Anatomy Dissection Course
Authors: Salomäki Tiina , Laakkonen Juha , Ruohoniemi Mirja
Published: November 2013

One way to improve students' learning outcomes and well-being is to change teaching practices to allow students to become more active participants. We used an anatomy dissection course to test a cooperative group work method in which first-year veterinary students took turns leading their peer group and were each responsible for teaching the anatomy of a particular topographic region. The important blood vessels, lymphatic system, and nerves of each region of the body were covered. Students felt that exploration of the entire topographic region helped them to acquire a comprehensive understanding of the respiratory apparatus and the cardiovascular and nervous systems. Assigning individual tasks to each group member resulted in sharing the workload equally. Open-ended comments revealed that support from other group members was important for the students' learning experience, but the results also offered insight into a lack of constructive criticism. While teaching was considered challenging, and even a stress factor that hindered learning for some students, group work was generally held to be supportive of learning. The results suggest that more thorough instruction of students in their group work and in their individual tasks is required. Some students experienced difficulty in expressing their concerns openly and in seeking guidance from teachers, demonstrating the need for further investigation regarding students' self-regulation skills. Comments from the open-ended responses suggest that use of a cooperative learning method in anatomy dissection courses not only deepens student understanding of a subject but also offers first-year students an opportunity to practice the generic skills that will be needed in their future profession.
Holistic Approach to Maintenance and Preservation of Transportation Infrastructure
Authors: Broomfield John P.
Published: November 2013

The median age of bridges in the National Bridge Inventory is about 44 years. Many bridges built to design codes that are older and less demanding than current codes will be required to exceed their original design lives. Therefore, state highway agencies will need to expend more resources to prevent deterioration of their bridges, and the most efficient ways of assessing and maintaining the stock of bridges must be found. In addition, new bridges must be designed for durability, and key components must be accessible and capable of being maintained. This paper discusses various deterioration mechanisms, such as fatigue, impacts, scour, concrete deterioration, and corrosion, that can affect current highway bridges; issues concerning durability, maintainability, assessment, and monitoring of bridges; rehabilitation of bridges; and design of new bridges. The training of new engineers and the provision of expertise and allocation of resources by state highway agencies are also discussed. A holistic approach to transportation infrastructure maintenance is viewed as ensuring that all relevant expertise and experience are available to contribute to the design, construction, maintenance, and rehabilitation of new and existing bridges.
Defining Bridge Preservation by Action Type
Authors: Johnson Michael B. , Bektas Basak Aldemir
Published: November 2013

There has been progressive interest from FHWA and state departments of transportation (DOTs) in considering bridge preservation an essential part of a comprehensive bridge program. The available definitions of bridge preservation give a conceptual overview; they do not identify specific bridge preservation actions. The objective of this study was to come up with a comprehensive list of bridge actions, as identified by bridge experts, and to identify the specific actions that the experts defined as preservation. A comprehensive list of 94 bridge actions was developed with input from 12 DOTs. Through an online survey, bridge experts were asked to classify each bridge action as operations, maintenance, preservation, rehabilitation, improvement, or replacement. Although the level of consensus in the final classification of the bridge actions varied, 64 actions were assigned to the same category by more than 50% of the respondents. The authors used the simple majority to determine an action's classification but reported the percentages for all categories, with the intention of presenting alternative criteria and related levels of response to the readers. Fifty-two percent of the actions were classified as maintenance; 15% of the actions were classified as preservation. Examples of bridge preservation actions included the addition of wearing surfaces to protect decks, painting to protect steel, and the mitigation of scour to protect the bridge. From the results, it appeared that industry professionals used “maintenance” and “preservation” almost interchangeably. A comparison between the results of this research and published text definitions of preservation found that the text definitions were very broad and included actions considered by the participants in this research to be maintenance, preservation, or rehabilitation.
Modeling Hurricane Hazards and Damage on Florida Bridges
Authors: Sobanjo John O. , Thompson Paul D. , Kerr Richard
Published: November 2013

The state of Florida is developing a risk-based decision support model, specifically for its state-maintained bridges, to handle the occurrence of natural hazards, such as hurricanes, tornadoes, floods, landslides, and wildfires. Many bridges in Florida are vulnerable to damage caused by these hazards. With a focus on hurricanes, this paper develops prediction models (estimates of likelihoods) based on historical data of hazard events in Florida, as well as on existing national models. The Poisson process was assumed for the occurrence of natural events; predictions were estimated for the annual probability of occurrence. It was observed that, on average, the probability of hurricane occurrence at bridge locations decreased with the hurricane intensity (category number). In comparison, wildfires, another common hazard, had the highest likelihood estimates of the natural hazards. With a focus on physical damage to bridges, the consequences of hurricanes were also estimated on the basis of historical data within Florida. The damaged bridge components and elements were identified, and the levels of damage and the associated repair costs were assessed.
Current Performance-Based Maintenance Methods to Improve Virginia Highways
Authors: de la Garza Jesus M. , Arcella Joseph L.
Published: November 2013

This research was completed in two phases. Phase 1 involved a miniscan study of the highway maintenance industry to identify current state-of-practice in performance-based maintenance contracting (PBMC). Information was gathered on domestic and foreign agencies currently using performance-based maintenance on highways. Phase 2 used the miniscan study information to build, compare, and analyze agency time lines, comparing the Virginia Department of Transportation (DOT) with others. Time lines included major milestones at each agency, that is, milestones that enabled innovation in the field of performance-based contracting. The purpose of comparing the Virginia DOT with other agencies was to provide the Virginia DOT with industry best practices as well as recommendations for future contract evolutions. Time lines were constructed for the Florida DOT, Main Roads of Western Australia, the Highways Agency of England, and the New Zealand Transport Agency. Connection links were made between the Virginia DOT and the other four agencies on the basis of similarities in procurement laws and maintenance milestones (i.e., first design–build project). Time line linkages and collection of information on benefits associated with PBMC (compared with traditional method-based maintenance) were used to make five recommendations for the Virginia DOT's future maintenance program. The Virginia DOT's recommendations were to use performance-based contracting on secondary roads, use areawide contracts to cover additional facilities, shift the Virginia DOT Turnkey Asset Maintenance Services’ focus from a lowest-cost to best-value approach similar to England's managing-agent contractor, devise a strategic network of highways to prioritize maintenance, and use key performance indicators to align maintenance division objectives with overall Virginia DOT organization. Recommendations also considered current restrictions imposed by Virginia procurement laws.
Asphalt Emulsion Sprayability and Drain-Out Characteristics in Chip Seals
Authors: Johannes Petrina T. , Bahia Hussain U.
Published: November 2013

Streaking and drain-out are two common early chip seal failures related to the viscosity of the asphalt emulsion used. An emulsion with a high viscosity at spraying could result in streaking, while another with a low viscosity after spraying could drain off the road surface under gravity. Some emulsions also tend to show reduction in viscosity during handling; this reduction aggravates the potential for drain-out. The Saybolt Furol viscometer [SFV (ASTM D7496-09)] is currently used to characterize the viscosity of asphalt emulsions. However, the SFV cannot be operated under varying shear rate conditions as experienced by emulsions at different stages. A new test procedure is presented for evaluating sprayability, drain-out, and recovery kinetics of emulsions with a rotational viscometer. The test procedure allows for emulsions to be tested at a higher shear rate to evaluate sprayability and at a low shear rate to evaluate drain-out. Twelve emulsions of different grades and chemistries were tested. Results showed that the proposed test procedure was sensitive to emulsion chemistry, grade, and testing temperature. Sprayability, drain-out, and recovery kinetics were found to be significantly affected by emulsion chemistry and testing temperature. This protocol with variable shear-rate viscosity is recommended for use as a basis for replacing the SFV test as a better performance-related test method. Specification criteria can be easily developed and implemented because rotational viscometers are widely available in the industry, and there is a wealth of experience with various emulsions in the field.
Beyond Landauer Erasure
Authors: Barnett Stephen , Vaccaro Joan
Published: November 2013

In thermodynamics, one considers thermal systems and the maximization of entropy subject to the conservation of energy. A consequence is Landauer’s erasure principle, which states that the erasure of one bit of information requires a minimum energy cost equal to kT ln(2), where T is the temperature of a thermal reservoir used in the process and k is Boltzmann’s constant. Jaynes, however, argued that the maximum entropy principle could be applied to any number of conserved quantities, which would suggest that information erasure may have alternative costs. Indeed, we showed recently that by using a reservoir comprising energy degenerate spins and subject to conservation of angular momentum, the cost of information erasure is in terms of angular momentum rather than energy. Here, we extend this analysis and derive the minimum cost of information erasure for systems where different conservation laws operate. We find that, for each conserved quantity, the minimum resource needed to erase one bit of memory is λ-1 ln(2), where λ is related to the average value of the conserved quantity. The costs of erasure depend, fundamentally, on both the nature of the physical memory element and the reservoir with which it is coupled.
Impact of Intragranular Substructure Parameters on the Forming Limit Diagrams of Single-Phase B.C.C. Steels
Authors: Franz Gérald , Abed-Meraim Farid , Berveiller Marcel
Published: November 2013

An advanced elastic-plastic self-consistent polycrystalline model, accounting for intragranular microstructure development and evolution, is coupled with a bifurcation-based localization criterion and applied to the numerical investigation of the impact of microstructural patterns on ductility of single-phase steels. The proposed multiscale model, taking into account essential microstructural aspects, such as initial and induced textures, dislocation densities, and softening mechanisms, allows us to emphasize the relationship between intragranular microstructure of B.C.C. steels and their ductility. A qualitative study in terms of forming limit diagrams for various dislocation networks, during monotonic loading tests, is conducted in order to analyze the impact of intragranular substructure parameters on the formability of single-phase B.C.C. steels.
Discrimination Method of the Volatiles from Fresh Mushrooms by an Electronic Nose Using a Trapping System and Statistical Standardization to Reduce Sensor Value Variation
Authors: Fujioka Kouki , Shimizu Nobuo , Manome Yoshinobu , Ikeda Keiichi , Yamamoto Kenji , Tomizawa Yasuko
Published: November 2013

Electronic noses have the benefit of obtaining smell information in a simple and objective manner, therefore, many applications have been developed for broad analysis areas such as food, drinks, cosmetics, medicine, and agriculture. However, measurement values from electronic noses have a tendency to vary under humidity or alcohol exposure conditions, since several types of sensors in the devices are affected by such variables. Consequently, we show three techniques for reducing the variation of sensor values: (1) using a trapping system to reduce the infering components; (2) performing statistical standardization (calculation of z-score); and (3) selecting suitable sensors. With these techniques, we discriminated the volatiles of four types of fresh mushrooms: golden needle (Flammulina velutipes), white mushroom (Agaricus bisporus), shiitake (Lentinus edodes), and eryngii (Pleurotus eryngii) among six fresh mushrooms (hen of the woods (Grifola frondosa), shimeji (Hypsizygus marmoreus) plus the above mushrooms). Additionally, we succeeded in discrimination of white mushroom, only comparing with artificial mushroom flavors, such as champignon flavor and truffle flavor. In conclusion, our techniques will expand the options to reduce variations in sensor values.
Induction of Apoptosis by 4-(3-(tert-butylamino)imidazo[1,2-α]pyridine-2-yl) Benzoic Acid in Breast Cancer Cells via Upregulation of PTEN
Authors: Siddharth Sumit , Mohapatra Purusottam , Preet Ranjan , Das Dipon , Satapathy Shakti Ranjan , Choudhuri Tathagata , Kundu Chanakya Nath
Published: November 2013

We have previously reported that 4-(3-(tert-butylamino)imidazo[1,2-α]pyridine-2-yl)benzoic acid, a bicyclic N-fused aminoimidazoles derivative (BNFA-D), possesses anticancer potentiality against breast and kidney cancer cells with minimal toxicities to corresponding
normal cells. Here, we explored the mechanism of action of BNFA-D in breast cancer cells using multiple cell-based assays such as MTT, DAPI, FACS, Western blot, and immunoprecipitation. BNFA-D caused apoptosis by upregulating PTEN leading to inhibition of Wnt/TCF signaling cascade and arresting
S phase in breast cancer cells. Expression levels of β-catenin, cyclin D1, C-MYC, and phospho-AKT (Ser473) decreased with simultaneous increase in the levels of GSK3β, CK1, and PTEN in BNFA-D-treated MCF-7 cells. Interestingly, silencing of PTEN in breast cancer cells
reversed the phenomenon of Wnt/TCF signaling cascade inhibition after BNFA-D treatment.
Inhibition of Cell Proliferation and Increase of Chemosensitivity by Simultaneous Knockdown of XIAP and Survivin in Pancreatic Carcinoma Cells
Authors: Yang Jianyi , Ouyang Jianhui , Ouyang Linqi , Ouyang Lu , Chen Yuxiang
Published: November 2013

At present, classic therapies provide limited benefits to the survival of patients with pancreatic cancer. However, clinically available gene therapy strategies have not been well established. This study investigates the effect of shRNA-mediated inhibition of XIAP and survivin expression
on the proliferation, apoptosis, and chemosensitivity of pancreatic cancer cells. Stable inhibition of XIAP and survivin expression in SW1990 and Panc-1 pancreatic cancer cells was established by lentivirus-carried shRNAs. The mRNA and protein expression of XIAP and survivin were detected
by real-time PCR and Western blot, respectively. Cell proliferation was measured by MTT assay, and apoptosis was detected by caspase-3/7 activity and Hoechst33342 staining. The lentivirus-carried shRNA significantly inhibited XIAP and survivin expression. Simultaneous inhibition of XIAP and
survivin expression in pancreatic cells significantly reduced cell proliferation, increased caspase-3/7 activity, and increased cell sensitization to 5-FU and gemcitabine treatments compared to inhibition of XIAP or survivin expression alone. However, simultaneous silencing of XIAP and survivin
showed no significant difference in inducing cell apoptosis compared to silencing of XIAP or survivin expression alone. Simultaneous inhibition of XIAP and survivin expression may be an effective strategy for gene therapy of pancreatic cancer.
Construction of the foundations of the PLE and PLN for collaborative learning
Authors: Marín-Juarros Victoria , Negre-Bennasar Francisca , Pérez-Garcias Adolfina
Published: November 2013

In this article we approach the topic of collaborative learning by means of the creation and maintenance of personal learning environments and networks (PLE and PLN) and their integration within institutional virtual learning environments (VLE) as strategies to enhance and foster collaborative learning. We take an educational point of view: the student learns independently and carries out activities in groups to achieve common goals. Our aim is to experiment with didactical methodologies of integration between the institutional VLE and PLE, and to analyze the university students’ construction of PLE. Due to its importance in facilitating and fostering collaborative learning, special emphasis is placed on the construction of the personal learning network. We performed a design-based research on an academic course for Primary teachers. The results show that the students construct their PLE and PLN using newly acquired knowledge and that an appropriate methodological integration takes place between these environments and the institutional VLE for integrated learning. As conclusion, we propose an integrative methodological model for collaborative learning as a good practice.

El aprendizaje colaborativo se puede afrontar desde diferentes estrategias. En este artículo contemplamos la creación y mantenimiento de entornos y redes personales de aprendizaje (PLEs y PLNs) y su integración en entornos virtuales institucionales de aprendizaje (EVEA) como estrategias que facilitan y promueven el aprendizaje colaborativo, siempre desde una visión educativa en la que el alumno es autónomo en su propio aprendizaje y trabaja para el logro de metas comunes mediante la realización de actividades de forma conjunta en grupos, existiendo interdependencias positivas. Los objetivos de este trabajo son experimentar con metodologías didácticas de integración del EVEA y los PLEs, y analizar la construcción del PLE por parte de los alumnos universitarios, haciendo especial énfasis en la construcción de la red personal de aprendizaje. Para ello se empleó una metodología de diseño y desarrollo, en una asignatura universitaria de los estudios de maestro de Primaria. Los resultados de la experiencia apuntan a que los alumnos construyen sus PLEs y PLNs en base a sus nuevos conocimientos adquiridos y se produce una adecuada integración metodológica entre esos entornos y el EVEA para el aprendizaje integrado. Como conclusión proponemos un modelo de organización metodológica de integración para el aprendizaje colaborativo a modo de buena práctica.
Collaboration and social networking in Higher education
Authors: Gewerc-Barujel Adriana , Montero-Mesa Lourdes , Lama-Penín Manuel
Published: November 2013

This paper presents an exploratory analysis of the experience of educational innovation in the configuration of a social learning network in a subject for the Education degree course at the University of Santiago de Compostela (Spain). This innovation is based on the premise of student-centered teaching (independent learning, self-regulated, authentic and breaking boundaries between formal and informal areas) enriched with collaborative activities. The study aims to analyze the intensity and relevance of the student´s contributions in this collaborative framework. We used learning analytics tools with two types of techniques: social network analysis (SNA) and information extraction, to measure the intensity, centrality and relevance of collaboration among students. The results obtained allow us to confirm: 1) The consistency and coherence between the pedagogical approach and the option of using a social network in university education; 2) A dense network with a high level of interaction, a moderate degree of centrality and a low centralization index (structure moves away from star), with a group with the capacity to influence the rest (degree of betweenness); 3) High level of relevance to the content analyzed; 4) The usefulness of learning analytics techniques to guide teacher decision-making.

El presente trabajo analiza, de forma exploratoria, la experiencia de innovación docente en la configuración de una red social de aprendizaje en una asignatura del Grado de Pedagogía de la Universidad de Santiago de Compostela. La innovación se justifica en las premisas de la enseñanza centrada en el alumno (aprendizaje autónomo, autorregulado y auténtico, ruptura de fronteras entre ámbitos formales e informales), enriquecida con actividades colaborativas. El estudio pretende analizar la intensidad y pertinencia de las aportaciones del alumnado en este marco colaborativo. Para ello se han utilizado herramientas informáticas de la analítica del aprendizaje (learning analytics) con dos tipos de técnicas: análisis de redes sociales y extracción de información, que dan cuenta de la intensidad, centralidad y relevancia de la colaboración entre los estudiantes. Los resultados obtenidos posibilitan concluir: 1) la consistencia y coherencia entre la propuesta pedagógica y la opción de utilizar una red social en la enseñanza universitaria; 2) la existencia de una red densa con alto nivel de interacción, grado de centralidad medio e índice de centralización bajo (estructura que se aleja de la forma estrella), con un grupo con capacidad de influencia en el resto (grado de intermediación); 3) alto nivel de pertinencia de los contenidos analizados; 4) la utilidad de las técnicas de analítica de aprendizaje para orientar la toma de decisiones del docente.