bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Welfare and Maternal Work on Recommended Preventive Care Utilization Among Low-Income Children
Authors: Holl Jane L. , Oh Elissa H. , Yoo Joan , Amsden Laura B. , Sohn Min-Woong
Published: October 2012

Objectives. We examined how maternal work and welfare receipt are associated with children receiving recommended pediatric preventive care services.

Methods. We identified American Academy of Pediatrics–recommended preventive care visits from medical records of children in the 1999–2004 Illinois Families Study: Child Well-Being. We used Illinois administrative data to identify whether mothers received welfare or worked during the period the visit was recommended, and we analyzed the child visit data using random-intercept logistic regressions that adjusted for child, maternal, and visit-specific characteristics.

Results. The 485 children (95%) meeting inclusion criteria made 41% of their recommended visits. Children were 60% more likely (adjusted odds ratios [AOR` = 1.60; 95% confidence interval [CI] = 1.27, 2.01) to make recommended visits when mothers received welfare but did not work compared with when mothers did not receive welfare and did not work. Children were 25% less likely (AOR = 0.75; 95% CI = 0.60, 0.94) to make preventive care visits during periods when mothers received welfare and worked compared with welfare only periods.

Conclusion. The Temporary Assistance for Needy Families maternal work requirement may be a barrier to receiving recommended preventive pediatric health care.
The Prompted Optional Randomization Trial: A New Design for Comparative Effectiveness Research
Authors: Flory James , Karlawish Jason
Published: October 2012

Randomized controlled trials are the gold standard for medical evidence because randomization provides the best-known protection against confounding of results.

Randomization has practical and ethical problems that limit the number of trials that can be conducted, however. A different method for collecting clinical data retains the statistically useful properties of randomization without incurring its practical and ethical challenges.

A computerized prompt introduces a random element into clinical decision-making that can be instantly overridden if it conflicts with optimal patient care. This creates a weak form of randomization that still eliminates the effect of all confounders, can be carried out without disturbing routine clinical care, and arguably will not require research-grade informed consent.
Changes in Soil Structure and Hydraulic Properties in a Wooded‐Shrubland Ecosystem following a Prescribed Fire
Authors: Chief Karletta , Young Michael H. , Shafer David S.
Published: October 2012

Pre‐ and post‐fire measurements were made for a low‐intensity prescribed fire in a semiarid, shrub‐woodland transition zone, and objectives were to: (i) determine changes in near‐saturated hydraulic conductivity (Kf measured with a tension infiltrometer), air permeability (ka measured with an air permeameter), and soil physical properties at shrub undercanopy and interspace microsites immediately before and after a fall burn and for a 13‐mo period; and (ii) quantify the importance and effect of post‐fire soil structure on hydraulic properties using pre‐ and post‐fire measurements. At undercanopy microsites, structure deteriorated from a moderate to a weak subangular blocky structure after the fire that broke down to a structureless soil 10 mo later. At interspace microsites, post‐fire soil structure deteriorated from a moderate‐strong subangular blocky structure with hard dry consistency to a weak subangular blocky structure with soft dry consistency. After 10 mo, the intercanopy maintained a weak‐moderate soil structure that became structureless‐weak after 13 mo. Immediately after the fire, at both microsites, there was incomplete organic combustion, a decrease in bulk density, and an increase in ka; however, at undercanopy microsites, there was no significant change in Kf even though there was a slight to moderate hydrophobicity, whereas at interspace microsites where no water repellency existed, Kf increased. These changes may be a result of expansion of vaporized water through soil pores that broke up aggregates, deteriorating soil structure. Thus, mechanisms that contributed to changes immediately and after the first year post‐fire were different for low‐intensity burns than for higher intensity burns.
The Impact of Different Root Exudate Components on Phenanthrene Availability in Soil
Authors: Sun Bingqing , Gao Yanzheng , Liu Juan , Sun Yandi
Published: October 2012

This study investigated the impact of different root exudate components (RECs) on the availability of phenanthrene as a representative of polycyclic aromatic hydrocarbons (PAHs) in soil (TypicPaleudalfs) using laboratory batch assays. Four typical RECs were compared including malic acid, alanine, serine, and fructose. An n‐butanol extraction procedure and a sorption–desorption experiment were used to predict the availability of phenanthrene in soil. We found that the n‐butanol extractable amounts of phenanthrene in soil increased with increasing REC concentrations. The extractability of phenanthrene in soil with various treatments decreased in the following order: malic acid > alanine > serine > fructose treatments. Organic acid (malic acid) resulted in the most significant increase in PAH extractability by soil. Phenanthrene sorption by soil could be described using a linear model regardless of the presence of RECs. The simulated distribution constants (Kd) and carbon‐normalized distribution constants (Koc) for phenanthrene sorption decreased significantly with the addition of all test RECs. Malic acid enhanced desorption of phenanthrene from soils. In contrast, lower concentrations of test amino acids promoted phenanthrene desorption, while higher concentrations inhibited desorption. Fructose had a minimal effect on PAH desorption. The mechanism of REC‐influenced availability of PAH in soil is discussed based on the observed metal dissolution, soil organic matter reduction, and dissolved organic matter release from soil solids.
Increase of Soil pH in a Solar Greenhouse Vegetable Production System
Authors: Song He , Guo Jingheng , Ren Tao , Chen Qing , Li Baoguo , Wang Jingguo
Published: October 2012

Acidification of agricultural soil is attributed to excessive reduced nitrogen (N) fertilizer application and enhanced nitrate leaching. However, after an initial pH decrease, an increase in soil pH was observed in a solar greenhouse study. Within the vegetable planting areas in China, 3.3 million hectares of vegetables are planted in similar solar greenhouses. The objectives were to clarify the origin of this alkalinity. The results showed that, from February 2009 to January 2010, the total H+ production rate by base cation (BC) uptake of tomato plants and applied N fertilizer was 50.4 kmol ha−1 yr−1 for the control (CK), 68.3 kmol ha−1 yr−1 for recommended N treatment (RN), and 68.9 kmol ha−1 yr−1 for conventional N treatment (CN). However, the alkalinity inputs by irrigation were 96.1, 76.0, and 71.3 kmol ha−1 yr−1 for treatment CK, RN, and CN, respectively. Considering the alkalinity inputs generated by lime‐containing chicken manure (CM) and plant removal of phosphorus (P), the net residual alkalinity was 47.6 kmol ha−1 yr−1 for CK, 25.5 kmol ha−1 yr−1 for RN, and 20.4 kmol ha−1 yr−1 for CN and resulted in a rise in soil pH of 0.6, 0.5, and 0.2 units, respectively. In addition, net BC accumulation caused by irrigation, P and potassium (K) fertilizers, and chicken manure was 68.5 kmol ha−1 yr−1 for CK, 104.3 kmol ha−1 yr−1 for RN, and 103.5 kmol ha−1 yr−1 for CN. Results indicated alkaline factors from irrigation water (IW) alleviated the acidification of greenhouse soil but may eventually accelerate soil salinization. Groundwater table declines because of overwithdrawal in the region may be responsible for the increases in base cations brought to the greenhouse soil by irrigation. Therefore, a better water management has to be considered in the region.
Soils Associated with Biotic Activity on Frost Boils in Arctic Alaska
Authors: Michaelson G. J. , Ping C. L. , Walker D. A.
Published: October 2012

Frost boils occur extensively across arctic tundra ecosystems, and biotic crusts form on the mineral soils exposed in centers of boils. These center areas of the frost boils eventually become completely covered by tundra vegetation. We studied the biogeochemistry of the surface soils (0‐ to 10‐cm depth) on frost boils at nine sites across a soil pH gradient in arctic Alaska. Soils under biotic crusts were compared with adjacent bare and fully vegetated areas within the centers of the same boil. Near the sea coast we found segregation of Na salts to the bare surface areas of boils and concentration of Ca under adjacent crusted areas within the boils. In contrast, inland coastal plain soils with nonacidic tundra showed Ca accumulation under both crusted and vegetated areas within the boils. Nonacidic soils rich in inorganic C were effective at buffering pH changes with organic carbon (OC) accumulations of up to 200 g kg−1. Soil water‐soluble OC (OCws) stocks of nonacidic boil sites correlated well with soil total OC (R2= 0.62,p< 0.01), while OCws for boils formed in acidic soils was correlated to total soil N stocks (R2= 0.69,p< 0.01), consistent with there being different limitations to soil biological activity for soils across the soil pH gradient. Although there were differences in quantity of accumulated organic matter across the soil pH gradient, soil nutrient pools increased as OC accumulated under crusted and then vegetated soils across all sites.
Soil‐Quality Effects of Grassland Degradation and Restoration on the Qinghai‐Tibetan Plateau
Authors: Dong S. K. , Wen L. , Li Y. Y. , Wang X. X. , Zhu L. , Li X. Y.
Published: October 2012

Alpine grassland and the soil on which it is growing in the Qinghai‐Tibetan Plateau (QTP) of China is being degraded in an attempt to increase food and feed production for an increasing global population. Our objective was to use soil quality assessment to quantify changes in soil chemical and physical properties at three depth increments (0 to 4, 4 to 10, and 10 to 20 cm) and thus determine the linkages between soil and vegetation changes, the soil element(s) limiting grassland restoration in alpine region, and the ability to restore soil fertility by reestablishing grasslands. The soil and vegetation were sampled in the different types of degraded grasslands, that is, moderately degraded grassland (MDG), heavily degraded grassland (HDG) and severely degraded grassland (SDG) as well as in the reestablished grasslands at different ages, that is, 5‐yr restored grassland (5yRG), 7‐yr restored grassland (7yRG), and 9‐yr restored grassland (9yRG) for comparative study. The results show: (i) decreased water holding capacity and increased soil hardness as vegetative cover declined, (ii) decreased soil organic carbon (OC) and total nitrogen (TN) and increased total soil potassium, (TK) (iii) the establishment of artificial grassland did not restore soil quality or nutrient stocks within degraded grassland soils, and (iv) yearly variations in soil properties at different depths were significant along the degree of grassland degradation. Significant variations of soil physical and chemical parameters might be attributed to loss of the top soil and changes of vegetation composition and soil and textures. Soil quality can be used to assess grassland degradation and restoration in the alpine region. In conclusion, better soil management is needed for restoring the degraded alpine grasslands on the QTP.
Fall Conservation Deep Tillage Stabilizes Maize Residues into Soil Organic Matter
Authors: Wingeyer Ana B. , Walters Daniel T. , Drijber Rhae A. , Olk Daniel C. , Arkebauer Timothy J. , Verma Shashi B. , Wedin David A. , Francis Charles A.
Published: October 2012

Efforts for increasing soil organic matter (SOM) content under agricultural systems have primarily focused on management practices that reduce exposure of SOM to decomposition via minimum tillage. We assess an alternative approach, termed “fall conservation deep tillage” (FCDT), to SOM stabilization through fall incorporation of crop residues into the soil profile together with N fertilizer. In an eastern Nebraska field under irrigated maize (Zea mays L.), we measured total soil C and N stocks on an equal soil mass basis (0‐ to 30‐cm depth) and the composition of four SOM fractions after 14 yr of previous no‐till management and 1, 2, and 3 yr after conversion to FCDT. After 3 yr of FCDT, redistribution of soil C, N, and soil organic matter fractions occurred within the soil profile; however, total soil C and N stocks remained unchanged. An increase in the soil—crop residue contact surface through FCDT increased free light fraction by 170% in deeper strata in the soil profile. Change from no‐till to FCDT led to initial reduction of C and N stocks as mobile and calcium bound humic acid fractions after 1 yr of tillage, suggesting enhanced decomposition and/or condensation. By the second and third years of FCDT, stabilization of crop residues into these humified fractions was significant. The trends observed after 3 yr of FCDT at field‐scale match prior plot‐scale experiments from the same region and suggest that a positive balance of soil C and N accrual and loss may be achieved by enhancing the soil‐residue contact surface in these soils.
Models Performance and Robustness for Simulating Drainage and Nitrate‐Nitrogen Fluxes without Recalibration
Authors: Jabro Jay D. , Jabro Ann D. , Fales Steven L.
Published: October 2012

Intensively grazed pastures generate nitrate‐nitrogen (NO3–N) contaminated groundwater creating grave environmental concern. Computer models simulate and forecast appropriate agricultural practices to reduce environmental impact. Model validation is an essential process in evaluation and field application of computer simulation models. The objectives of this study were to assess and compare robustness and performance of three models—LEACHM (Leaching Estimation and Chemistry Model), NCSWAP (Nitrogen and Carbon Cycling in Soil, Water, And Plant), and SOIL‐SOILN—for simulating drainage flux and NO3–N leaching in an intense pasture system without recalibration. A 3‐yr study was conducted on a Hagerstown silt loam to measure drainage and NO3–N fluxes below 1 m depth from N‐fertilized orchardgrass (Dactylis glomerata L.) using intact core lysimeters. Five N‐fertilizer treatments were replicated five times in a randomized complete block experimental design. The models were validated under orchardgrass using soil, water, and N transformation rate parameters and C pools fractionation derived from a previous study conducted on similar soils under corn (Zea mays L.). The model efficiency (MEF) of drainage and NO3–N fluxes were 0.53, 0.69 for LEACHM; 0.75, 0.39 for NCSWAP; and 0.94, 0.91 for SOIL‐SOILN. The models failed to produce reasonable simulations of drainage and NO3–N fluxes in January, February, and March due to limited water movement associated with frozen soil and snow accumulation and melt. The differences between simulated and measured NO3–N leaching and among models' performances may also be related to soil N and C transformation processes embedded in the models. Generally, the results demonstrate the potential of these three models to reasonably simulate annual and monthly drainage and NO3–N fluxes under the pasture system without recalibration.
Controlled Release Urea Improved Nitrogen Use Efficiency, Activities of Leaf Enzymes, and Rice Yield
Authors: Yang Yuechao , Zhang Min , Li Y.C , Fan Xiaohui , Geng Yuqing
Published: October 2012

The effects of a controlled release urea (CRU) on concentration of N in root zones, activities of N metabolism enzymes in leaves, and N use efficiency of rice (Oryza sativaL.) grown on a silt loam soil in lysimeters were investigated. The entire amount (100–300 kg N ha−1) of the CRU was incorporated into a plug for growing the rice seedlings while the regular urea was split into three applications (the standard practice). Results indicated that the N release of CRU closely matched the N requirements of the rice, and the commingling of the CRU with the rice seeds increased N concentration within the root zone and enhanced the activities of glutamine synthetase (GS), glutamine 2‐oxoglutarate amidotransferase (GOGAT) and nitrate reductase (NR) in leaves. At the same N rate, the apparent N use efficiency of the CRU applied at 300 kg N ha−1was 27.6 and 22.9% higher than that of conventional urea treatment in 2007 and 2008, respectively. Although the CRU at 200 kg N ha−1supplied one‐third less N than the urea at 300 kg N ha−1, the CRU produced 3 to 5.9% more grain than the urea. Placing the CRU with rice seeds without additional fertilizer application during the entire growing season significantly increased N availability in soils and improved rice growth and led to use of less N fertilizers for greater rice grain yield.
Biofilms and bacteriological water quality in a domestic installation model simulating daily drinking water consumption
Authors: Tsvetanova Z. G. , Dimitrov D. N.
Published: October 2012

The biofilm formation potential of a drinking water supply system is related to the chemical, microbiological and hydrodynamic characteristics of water, and to the pipe materials in contact with water flow. The goals of this study were: to determine the biofilm dynamics in a model of four drinking water installations, to simulate daily household water consumption; to compare the biofilms developed on different polymer pipe materials and their influence on bacteriological water quality. The results demonstrated that bacterial density of biofilms depended on pipe material type and was influenced by water temperature. The biofilms on polyvinylchloride chlorinated and polyethylene materials had higher bacterial density than biofilms on polypropylene (PP) brands. The effect of the materials, and respectively the biofilms, on drinking water quality was stronger in the overnight stagnation periods, especially during the initial weeks of model operation, than in periods of water consumption. Heterotrophic plate count (HPC) in stagnant or in flowing waters and water temperature followed a similar curve pattern, demonstrating significant seasonal variations. In summer, the HPC values of stagnant waters were raised up to seven times higher than in winter and those of the outlet waters (during the consumption periods) were raised up to four times.
Sustainable water resources management in the Long Bien district of Hanoi, Vietnam
Authors: Stefan C. , Fröhlich T. , Fuchs L. , Junghanns R. , Phan H. M. , Tran V. N. , Werner P.
Published: October 2012

The accelerated industrialization of Hanoi, Vietnam, coupled with a high population growth rate and changing climatic conditions create increasing pressure on the local water balance. Despite abundant precipitations, overexploitation endangers the groundwater resources, which are not able to sustain an adequate water supply. The present paper presents a sustainable approach for balancing the lowering of groundwater levels by increasing the rainwater percolation rates through enhanced infiltration. The efficiency of the method was assessed by a scenario analysis based on hydrological and hydrogeological models. Multi-criteria simulations revealed the optimum infiltration sites by considering technical and site-specific aspects and the positive impact of artificial recharge on seasonal groundwater budget.
Energy and environmental costs related to water supply in Mexico City
Authors: Salazar R. , Rojano A. , López I.
Published: October 2012

Water and energy are critical resources that are essential and interdependent. Satisfying consumers' water needs requires energy for supply, purification, distribution, and treatment of water and wastewater. This energy consumption to provide water is linked with negative environmental externalities. This paper provides an overview of the energy and environmental costs related to water supply services in Mexico City, one of the largest cities in the world; this city is heading towards a major water crisis, more than 30% of its water supply comes from external sources. The internal groundwater sources are overexploited between 9 and 12 m3/s generating 6–28 cm of sinking every year. The current water availability is 130 lt/person/day, which is below the minimum requirements. Also, half of Mexico City's water supply is lost through poor infrastructure alone and mismanagement of water resources. The external and internal sources of water supply are analyzed in terms of the energy consumption and costs as well as the generation of contaminants in the atmosphere such as CO2, SO2, N2O. Finally, some opportunity areas are provided to reduce energy use and contamination of the non-sustainable water consumption pattern of Mexico City.
The water governance challenge: the discrepancy between what is and what should be
Authors: Ravnborg H. M. , Jensen K. M.
Published: October 2012

In 2010, the UN General Assembly declared the right to safe and clean drinking water and sanitation as a human right that is essential for the full enjoyment of life and all human rights. Yet, findings from the Competing for Water research programme suggest that all too often, people in need of water for domestic purposes lose out to people and companies who claim access to water for productive purposes. Likewise, in many countries, specific water authorities at national as well as basin and watershed level have been formed and assigned the responsibility to allocate water according to the water policy and the associated legal framework. Yet, findings from the Competing for Water research programme show that real-world water allocation takes place through a wide array of institutions, ranging from the rural community, over agreements mediated by local lawyers, district officials and non-governmental organisations, to decisions made in the president's office. The Competing for Water programme entails empirical research conducted in Bolivia, Mali, Nicaragua, Vietnam and Zambia. Based on findings from this research, this paper identifies the discrepancies between statutory and actual water governance, analyses the underlying causes and explores the implications for ongoing water governance reform.
Degradation of surfactant SLS in water by singlet oxygen generated by the reaction between hydrogen peroxide and hypochlorite
Authors: Teixeira Luiz Alberto Cesar , de Faria Gardingo Mariana , Yokoyama Lidia , da Fonseca Araujo Fabiana Valeria
Published: October 2012

The synergistic aqueous combination of hydrogen peroxide and hypochlorite which results in the formation of the highly oxidizing intermediate species singlet oxygen (1O2) was effective in the degradation of the anionic surfactant sodium lauryl sulphate (SLS) in water. The process was effective in the near neutral pH range of 6–8, and up to initial SLS concentration values of 10 mg/L. For initial [SLS] = 5 or 10 mg/L, pH = 6–8, and excess molar ratio ([H2O2] + [NaClO])/[SLS] = 5:1 it was possible to achieve a final concentration of [SLS] < 0.5 mg/L (95% degradation) in t = 60 min at 25 °C in a batch reaction. By comparison, the same reaction with either of the separate oxidants (only H2O2 or only NaClO) at the same excess molar ratio oxidant/SLS of 5:1 gave a maximum of about 50% degradation of the SLS over the same 60 min reaction time. An empirical rate equation was derived: −d[SLS]/dt = k[SLS]0.8([H2O2] + [NaClO])0.3, with k = 4.8 (±1.0) × 10–1 L/mol s at 25 °C.
A construction of water quality index considering physicochemical properties for drinking purposes in a rural settlement: a case study of Gajraula region, Ganga River Basin (North India)
Authors: Singh Bineet , Chauhan Jaspal Singh , Mohan Anuraag
Published: October 2012

A simple methodology based on several key variables of groundwater chemistry is used to create a water quality index (WQI), with the aim of monitoring the influence of industrial and rapid urbanization on a typical rural settlement. The applicability of the constructed indices as an assessment and communication tool is evaluated in a case study of Gajraula and its suburb of JP Nagar district in northern India. The water quality data from 2007 to 2009 were analysed for 12 different locations surrounding Gajraula for two seasons, i.e. wet and dry. Five point rating scale was used to classify water quality for each of the study locations. Rating curves were drawn based on the tolerance limits of drinking waters. In the present study, the WQI demonstrated a modest increase in wet seasons (August to November) than dry seasons (February to June) for all locations with a few exceptions. Hardness, total dissolved solids, NO3−, biochemical oxygen demand, and Fe in most cases were found to be responsible for the decline in seasonal WQI for various locations. However, the WQI around Gajraula varied from 50.6 to 87.7 and was found to be satisfactory except for some locations.
Impacts of pH-dependent metal speciation on the decomposition of triclosan by sulfate radicals
Authors: Nfodzo Prince , Hu Qinhong , Choi Hyeok
Published: October 2012

The presence of triclosan (TCS) in water resources has drawn significant attention due to its endocrine disruption potential. Sulfate radicals (SRs), generated particularly by the metal-mediated activation of peroxymonosulfate (PMS), have been proposed to effectively decompose TCS and many other pharmaceuticals and personal care products. In spite of its significance for understanding the efficiency of SR generation and catalytic/non-catalytic nature of the oxidation reaction, metal speciation has not been adequately highlighted in previous studies. This study investigated the detailed changes in metal speciation in cobalt/PMS and iron/PMS systems and correlated it with TCS decomposition under different pH conditions. A rapid oxidation of Co2+ to Co3+ and Fe2+ to Fe3+ generally corresponded with pseudo-steady state decomposition kinetics of TCS after its initial fast decomposition. The presence of potential threshold concentrations of metals to effectively activate PMS was found. A strong catalytic activity was observed for Co/PMS system at pH 3, where most of Co was present in the form of dissolved Co2+. The pH impacts were different for Co/PMS and Fe/PMS. TCS oxidation was fast at pH 5 for Co and pH 3 for Fe. However, long-term mineralization of TCS seemed less dependent on pH.
The sustainability performance of the water and sanitation services in Santiago de Chile
Authors: Simon Laura Margarete , Lehn Helmut
Published: October 2012

The water and sanitation sector in the Metropolitan Region of Santiago de Chile (MRS) is mainly privately owned or operated. The sector prides itself on having a modern and effective regulatory framework. Nevertheless there are still sustainability deficits existing as far as governance structures and integrated water resource management are concerned. This paper analyzes the sustainability performance of the sector by using integrated sustainability indicators. The research focuses on institutional and governance aspects and the ecological, economic and social impacts of the newly privatized water and sanitation sector. Detected sustainability deficits, conclusions and possibilities for actions are presented.
Water reuse in the Kingdom of Saudi Arabia – status, prospects and research needs
Authors: Drewes Jörg E. , Patricio Roa Garduño C. , Amy Gary L.
Published: October 2012

Saudi Arabia is one of the driest countries in the world. While desalination plants currently installed in the country represent 30% of the world's desalination capacity, seawater desalination alone will not be able to provide sufficient supplies to meet the increasing freshwater demand. However, with only 9% of the total municipal wastewater generated currently being reused, the kingdom is projected as the third largest reuse market after China and the USA, and reuse capacities are projected to increase by 800% by 2016. This projected growth and the change in water portfolios offer tremendous opportunities to integrate novel approaches of water reclamation and reuse. This paper highlights the current status of reuse in the kingdom, discusses prospects of using distributed infrastructure for reuse tailored to local needs as well as the use of artificial recharge and recovery systems for reclaimed water. It also suggests research needs to helping overcoming barriers for wastewater reuse.
Development of automatic coagulant dosage control technology for rapid change of raw water quality parameters
Authors: Sangu Y. , Yokoi H. , Tadokoro H. , Tachi T.
Published: October 2012

An automatic coagulant dosage control technology for water purification plants was developed to deal with rapid changes of raw water quality parameters. Control logic was developed to decide coagulant dosage based on aluminum concentration in rapid mixing tank water based on results of semi-pilot scale experiments. This logic enabled quick feedback on the excess or lack of coagulant. It was found that the aluminum residual rate, which was proposed as an indicator of coagulation reactions, could be given as a function of coagulant dosage and turbidity. The effectiveness of the control logic was verified in semi-pilot scale experiments. Settled water turbidity was within ±0.5 NTU of target value even when raw water turbidity increased rapidly up to 100 NTU.
Primary Sclerosing Cholangitis - Current Issues in Clinical Practice
Authors: Corless L. , Tsai H.
Published: October 2012

Aims:

To review current issues in the diagnosis and treatment of primary sclerosing cholangitis.

Methods:

search of PubMed using the terms “primary sclerosing cholangitis”, “PSC”, “cholangitis” and “cholestasis”, as well as by review of current guidelines from the major international liver societies.

Results:

Primary sclerosing cholangitis is still a challenging condition to diagnose and manage, but newer imaging
modalities like MRCP and timing of liver transplantation point the way forward.
Public space and free action: Foucault vs. Lefebvre
Authors: Prodanovic Srdjan , Krstic Predrag
Published: October 2012

In this paper we will try to offer a systematic insight into the relation of
everyday practices and public space. By examining the work of two of the most
influential authors in this field, Foucault and Lefebvre, we will try to
provide a theoretical explanation of intuition that (public) space represents
one of the key constitutive elements of free action. In the first part of the
paper, we will consider Foucault?s notion of heterotopia in the interest of
pointing towards a ?spatially intermediated? self-reflection which, to a
great degree, resembles the philosophical askesis form his so called letter
work. Afterwards, we will consider in which sense Lefebvre?s position that
public space represents a Hegelian concrete abstraction - which entails
dialectical analysis and tracking of complex historical contradictions -
complements and deepens perspective that Foucault puts before us in his
heterotopias. In that vein, it will be shown that both authors, despite the
difference in their theoretical starting points, defend the idea of such a
public space in which all signifiers are removed in the interest of ?opening
space? for the free agent.
Numerical Investigation of Knee–Thigh–Hip Injuries in Frontal Vehicle Collisions
Authors: Heath Douglas R. , Silvestri Chiara , Ray Malcolm H.
Published: October 2012

Recent improvements to occupant restraint systems, such as seat belts and airbags, have caused a shift in the injury profile that results from vehicle collisions from primarily upper body to primarily lower extremity injuries. Injuries of the knee–thigh–hip (KTH) region have been shown to be some of the most debilitating. This project used a finite element model of the KTH region to study injury. A parametric investigation was conducted; the finite element KTH was simulated as a vehicle occupant positioned to a range of precrash driving postures. Results indicated that timing between a significant rise in foot–floor and knee–bolster contact force affected knee kinematics and axial force absorbed by the KTH region. Findings also suggest that introducing a lag time between the respective contacts may decrease the likelihood of KTH bone injury.
Commercial Driver Factors in Run-off-Road Crashes
Authors: Peng Yiyun , Boyle Linda Ng
Published: October 2012

The number of commercial vehicles on U.S. roads has grown dramatically over the past few decades. Although the number of large trucks involved in fatal and injury crashes has decreased over the past 20 years, large trucks still have a higher fatal crash involvement rate than passenger cars do. This study sought to gain insights on the impact of commercial driver factors on crash severity with respect to single-vehicle, run-off-road (ROR) crashes. A logistic model was conducted with large truck crash data from the Washington State Department of Transportation (years 2006 to 2009). The model predicted the effects of truck driver distraction, inattention, speeding, seat belt usage, and drowsiness and fatigue on the likelihood of an ROR crash involving injury or fatality. Other factors, such as environmental conditions, roadway types, and truck-related factors, were controlled in the model. Results indicated that speeding, drowsiness and fatigue, and distraction and inattention strongly affected increasing crash severity. As expected, seat belt use significantly decreased the severity of an ROR crash. The study confirms that several driver factors observed in other studies on crash likelihood are also significant for ROR crashes involving large trucks.
Development and Testing of Heat- and Mass-Coupled Model of Snow Melting for Hydronically Heated Pavement
Authors: Xu Huining , Tan Yiqiu
Published: October 2012

Hydronic heating has been used to prevent ice formation and snow accumulation on road surface pavements with the aim of improving driver safety. A two-dimensional heat- and mass-coupled model for melting snow on a hydronically heated pavement is described. The extended Darcy law and continuity equation were adopted to describe water flow caused by moisture and temperature gradients. To solve the complex nonlinear equation set, an explicit finite difference method is used. The snow-melting model was evaluated with data measured from snow-melting experiments performed at the Harbin Institute of Technology in Heilongjiang, China. Results show that the model is capable of providing good simulations of the evolution of temperature and surface conditions during snowmelt. Simulation comparisons indicate that including the effects of melted snow on thermal properties is important in the simulation of temperature and surface condition during snowmelt.
Project Emissions Estimator
Authors: Mukherjee Amlan , Cass Darrell
Published: October 2012

Because of the need to address challenges of global climate change, a project-based framework was developed and implemented for life-cycle assessment (LCA) that could be used to estimate the carbon footprint for typical construction work items in highway reconstruction and rehabilitation projects. The proposed framework considers the life-cycle emissions of products and processes involved in the raw material acquisition and manufacturing phase as well as the pavement construction phase. The framework also accounts for emissions from vehicular use and maintenance operations during the service life of the pavement. The framework introduces methods based on LCA to develop inventories of project emissions for highway construction, rehabilitation, and maintenance projects as well as to analyze inventories for the calculation of project-level construction metrics for estimating emissions. Fourteen highway construction and rehabilitation projects in Michigan were used to implement the method and validate the approach. In addition, the project emissions estimator (PE-2), a web-based tool that can be used to estimate and benchmark the carbon dioxide footprint of highway construction projects, is introduced. Results further the understanding of LCA methods for pavements while providing an emission estimation tool that can be used by decision makers to monitor and assess project emissions.
Model of Passenger Flow Assignment for Urban Rail Transit Based on Entry and Exit Time Constraints
Authors: Zhou Feng , Xu Rui-hua
Published: October 2012

The rail transit system in China has established network operations in many major cities, such as Shanghai and Beijing. With the automatic fare collection (AFC) system, a passenger can buy one ticket at the origin station and complete travel between two stations of different rail lines, an improvement in convenience for passengers. However, there may be many paths between the origin station and the destination station, and the path chosen by passengers cannot be determined simply. Thus, the problem of passenger flow assignment on the network arises. The AFC system can record the entry and exit times of passengers exactly, and the train operation plan can be obtained by train timetables. Because of the entry and exit times and the train operations, the range of feasible paths chosen by one passenger may be narrow. A passenger flow assignment model was devised, and an algorithm process was designed that calculates the chosen possibility of every feasible path and then matches the passengers to the most likely paths. Actual passenger data from the Beijing subway were used to verify the model and algorithm.
Evaluation of Link Criticality for Day-to-Day Degradable Transportation Networks
Authors: Li Jian , Ozbay Kaan
Published: October 2012

The evaluation of link criticality is an important step for public officials to apply when planning hazard mitigation. However, this type of analysis presents numerous challenges for capturing the impact of highly stochastic hazard events accurately. An analytical framework and an efficient solution procedure for the evaluation of link criticality are proposed: those tools consider the impact of day-to-day degradable conditions in transportation networks. Link capacity was examined as a multistatus variable, and a sampling technique was used to generate realizations of capacity value for transportation networks. With different capacity realizations, traffic demand was repeatedly assigned on the regional planning model network. The assignment results were measured with multiple criteria and analyzed with several statistical indices. A case study based on a section of the New Jersey roadway network verified the proposed approach.
Culvert Asset Management Practices and Deterioration Modeling
Authors: Salem Ossama , Salman Baris , Najafi Mohammad
Published: October 2012

Drainage infrastructure systems and culverts constitute an important portion of highway assets that require routine inspections, maintenance, and timely repair and renewal. Variations in structural characteristics (i.e., material type, shape, and dimension), environmental exposure, and wide geospatial distribution of these infrastructure assets accompanied with strict budget restrictions pose significant challenges for transportation agency officials. Deterioration models constitute one of the most essential components of any infrastructure asset management strategy; these models provide insight on the significant factors that affect infrastructure condition states and expected behavior of infrastructure assets under different conditions. The objectives of this study are to provide a review of previous studies on factors that affect culvert performance and durability and those on culvert asset management, to present current practices of transportation agencies with regard to management of culverts, and, last, to present development of a preliminary deterioration model that will allow decision makers to identify significant factors that affect deterioration of metal culverts and prioritize inspection procedures. The preliminary deterioration model presented in this study is developed by employing binary logistic regression with a forward stepwise variable selection method on data obtained from the Ohio Department of Transportation.
Probabilistic Models to Evaluate Effectiveness of Steel Bridge Weld Fatigue Retrofitting by Peening
Authors: Walbridge Scott , Fernando Dilum , Adey Bryan T.
Published: October 2012

The purpose of this study was to evaluate, with two probabilistic analytical models, the effectiveness of several alternative fatigue management strategies for steel bridge welds. The investigated strategies employed, in various combinations, magnetic particle inspection, gouging and rewelding, and postweld treatment by peening. The analytical models included a probabilistic strain-based fracture mechanics model and a Markov chain model. For comparing the results obtained with the two models, the fatigue life was divided into a small, fixed number of condition states based on crack depth, similar to those often used by bridge management systems to model deterioration due to other processes, such as corrosion and road surface wear. The probabilistic strain-based fracture mechanics model was verified first by comparison with design S–N curves and test data for untreated welds. Next, the verified model was used to determine the probability that untreated and treated welds would be in each condition state in a given year; the probabilities were then used to calibrate transition probabilities for a much simpler Markov chain fatigue model. Then both models were used to simulate a number of fatigue management strategies. From the results of these simulations, the performance of the different strategies was compared, and the accuracy of the simpler Markov chain fatigue model was evaluated. In general, peening was more effective if preceded by inspection of the weld. The Markov chain fatigue model did a reasonable job of predicting the general trends and relative effectiveness of the different investigated strategies.
Are Cell Phone Samples Needed for Studies of Walking Activity?
Authors: Lachapelle Ugo , Weiner Marc D. , Noland Robert B.
Published: October 2012

The growth in cell phone–only households represents a challenge for the collection of survey data. Cell phone–only households have distinct sociodemographic characteristics, which may result in different travel behavior. To explore those differences, as well as to investigate the impact of including a cell phone component in active transportation research, a representative sample of New Jersey households was surveyed with a random digit dial survey that included 1,200 completed interviews (800 based on a statewide landline sample, 400 from a landline over sample of Jersey City) and 311 statewide cell phone interviews, of which 80 were cell phone–only respondents. The survey explored walking behavior and perceived characteristics of the pedestrian environment. Sociodemographic characteristics, the frequency of walking, and home location characteristics were compared with chisquare tests of significance between sample pairs as well as multivariate analysis (ordered probit). Cell phone–only respondents were typically younger and poorer, with a greater proportion of renters, carless households, and minorities. It was found that cell phone–only household members walked more frequently, but this finding was because of their distinct sociodemographic characteristics, not their cell phone use per se. The implication for any analysis of rates or trends in walking (and probably other travel behavior) is that cell phone–only households must be included through a cell phone sample supplementing a landline sample. However, in the absence of a cell phone supplement, multivariate analysis of the correlates of walking may not be overly biased if sociodemographics relevant to cell phone–only respondents are collected and included in the analysis.
Capturing and Representing Multimodal Trips in Travel Surveys
Authors: Clifton Kelly , Muhs Christopher D.
Published: October 2012

Multimodal trips, or trips that use more than one means of transportation, have historically been underrepresented in travel surveying efforts. This lack of consideration has implications for widely accepted statistics for nonmotorized travel behavior (walking, bicycling, etc.) and affects researchers and professionals in travel modeling, urban planning, public health, and urban design. However, interest in the “last mile” connections to transit, aggregate health impacts of short walking trips, and emphasis on local connectivity require more detailed information on these typically short but important stages of travel. This study reviews approaches to multimodal travel behavior in travel surveys, analyzes their implications, and makes recommendations to improve data collection for the purpose of improved representation of multimodal travel. Particular attention is given to transit access and egress trip segments, nonmotorized travel, use of technology in travel surveys, reporting data, and dissemination of the travel survey beyond the travel forecasting community.
Radio Frequency Identification System to Measure Crossing and Wait Times of Commercial Vehicles at U.S. Border Crossings
Authors: Rajbhandari Rajat , Villa Juan Carlos
Published: October 2012

The design and deployment processes described in this study were used for deployment of a system based on radio frequency identification technology at the Pharr–Reynosa International Bridge in Pharr, Texas. The overall goal of this deployment was to implement a system that would automatically and reliably collect, archive, and disseminate wait times and crossing times of U.S.-bound commercial vehicles at international land border crossings and thereby monitor the performance of these crossings. Such performance measures provide stakeholder agencies and users with information to assist in various travel-related decisions, establish a common denominator to estimate the effect of improvements and modifications in operation, and establish indices that can be easily communicated to a nontechnical audience and still remain relevant. Results are also described from the initial analysis of wait and crossing times of U.S.-bound commercial vehicles at the border crossing. Researchers believe that the study will greatly benefit stakeholder agencies at the border that want to implement similar systems to measure border crossing performance. At the same time, the research community can benefit from the real-time and archived data, and it is expected that new research opportunities focused on performance measurement and monitoring of international border crossings will be generated.