bluuebunny/crossref_metadata_2025 huggingface dataset:
Fetal microchimerism and maternal health during and after pregnancy
Authors: O'Donoghue Keelin
Published: January 2009

Trafficking of fetal cells into the maternal circulation begins very early in pregnancy and the effects of this cell traffic are longlasting. All types of fetal cells, including stem cells, cross the placenta during normal pregnancy to enter maternal blood, from where they may be recovered in pregnancy for the purpose of genetic prenatal diagnosis. Fetal cells can also be located in maternal tissues during and after pregnancy, and persist as microchimeric cells for decades in marrow and other organs. Although persistent fetal cells were first implicated in autoimmune disease, subsequent reports routinely found microchimeric cells in healthy tissues and in non-autoimmune disease. Parallel studies in animal and human pregnancy now suggest instead that microchimeric fetal cells play a role in the response to tissue injury. However, it is still not clear whether microchimeric fetal cells persisting in the mother are an incidental finding, are naturally pathogenic or act as reparative stem cells, and the environmental or biological stimuli that determine microchimeric cell fate are as yet undetermined. Future studies must also focus on investigating whether fetal cells create functional improvement in response to maternal injury and whether this response can be manipulated.

The pregnancy-acquired low-grade chimeric state of women could have far-reaching implications, influencing recovery after injury or surgery, ageing, graft survival after transplantation, survival after cancer as well as deciding the protective effect of pregnancy against diseases later in life. Lifelong persistence of fetal cells in maternal tissues may even explain why women live longer than men.
Anorexia nervosa in pregnancy: a case report and review of the literature
Authors: Dinas K , Daniilidis A , Sikou K , Tantanasis T , Kasmas S , Tzafettas J
Published: January 2009

Anorexia nervosa is a complex illness rarely encountered in pregnant women. It is a disorder characterized by markedly decreased food intake accompanied by a distorted body image, resulting in an inability to maintain the body weight within 85% of ideal body weight. We describe a case of a pregnant woman diagnosed with anorexia nervosa at 28 weeks of gestation. Her body mass index was 17 kg/m2. A live male infant weighing 2,08 kg was delivered prematurely via vaginal delivery at 35 weeks of gestation. Pregnant women with anorexia nervosa may have a higher risk of hypertension, miscarriage, difficult labour, premature delivery and intrauterine growth restriction. Management of pregnancy complicated with anorexia nervosa requires involvement of a multidisciplinary team and hospitalization in severe cases.
Investigating the specificity and stoichiometry of RNA binding by the nucleocapsid protein of Bunyamwera virus
Authors: Mohl Bjorn-Patrick , Barr John N.
Published: January 2009

Bunyamwera virus (BUNV) is the prototypic member of both the Orthobunyavirus genus and the Bunyaviridae family of negative stranded RNA viruses. In common with all negative stranded RNA viruses, the BUNV genomic and anti-genomic strands are not naked RNAs, but instead are encapsidated along their entire lengths with the virus-encoded nucleocapsid (N) protein to form a ribonucleoprotein (RNP) complex. This association is critical for the negative strand RNA virus life cycle because only RNPs are active for productive RNA synthesis and RNA packaging. We are interested in understanding the molecular details of how N and RNA components associate within the bunyavirus RNP, and what governs the apparently selective encapsidation of viral replication products. Toward this goal, we recently devised a protocol that allowed generation of native BUNV N protein that maintained solubility under physiological conditions and allowed formation of crystals that yielded high-resolution x-ray diffraction data. Here we extend this work to show that this soluble N protein is able to oligomerize and bind RNA to form a highly uniform RNP complex, which exhibits characteristics in common with the viral RNP. By extracting and sequencing RNAs bound to these model RNPs, we determined the stoichiometry of N-RNA association to be ∼12 nucleotides per N monomer. In addition, we defined the minimal sequence requirement for BUNV RNA replication. By comparing this minimal sequence to those bound to our model RNP, we conclude that N protein does not obligatorily require a sequence or structure for RNA encapsidation.
Perspective—Tacit Knowledge and Knowledge Conversion: Controversy and Advancement in Organizational Knowledge Creation Theory
Authors: Nonaka Ikujiro , von Krogh Georg
Published: January 2009

Nonaka's paper [1994. A dynamic theory of organizational knowledge creation. Organ. Sci. 5(1) 14–37] contributed to the concepts of “tacit knowledge” and “knowledge conversion” in organization science. We present work that shaped the development of organizational knowledge creation theory and identify two premises upon which more than 15 years of extensive academic work has been conducted: (1) tacit and explicit knowledge can be conceptually distinguished along a continuum; (2) knowledge conversion explains, theoretically and empirically, the interaction between tacit and explicit knowledge. Recently, scholars have raised several issues regarding the understanding of tacit knowledge as well as the interaction between tacit and explicit knowledge in the theory. The purpose of this article is to introduce and comment on the debate about organizational knowledge creation theory. We aim to help scholars make sense of this debate by synthesizing six fundamental questions on organizational knowledge creation theory. Next, we seek to elaborate and advance the theory by responding to questions and incorporating new research. Finally, we discuss implications of our endeavor for organization science.
Intraorganizational Networks, Interorganizational Networks, and the Impact of Central Inventors: A Longitudinal Study of Pharmaceutical Firms
Authors: Paruchuri Srikanth
Published: January 2009

This paper proposes that a mechanism through which a firm's location in the interorganizational network influences the firm's internal innovation activities is modifying the amount of information flowing within the firm. Exploring a firm's internal innovation activities, I hypothesized that structural centrality of an inventor in the intrafirm coinventing network is associated with her impact on her firm's innovation activities in an inverted-U-shape relation. I further hypothesized that this relationship is moderated by the firm's centrality and span of structural holes in the interfirm network. I found strong support for these hypotheses in a longitudinal study of eight large pharmaceutical firms. The findings in this paper, apart from having managerial implications, have implications for research on alliances, network studies, and innovation processes.
Structural Differentiation and Ambidexterity: The Mediating Role of Integration Mechanisms
Authors: Jansen Justin J. P. , Tempelaar Michiel P. , van den Bosch Frans A. J. , Volberda Henk W.
Published: January 2009

Prior studies have emphasized that structural attributes are crucial to simultaneously pursuing exploration and exploitation, yet our understanding of antecedents of ambidexterity is still limited. Structural differentiation can help ambidextrous organizations to maintain multiple inconsistent and conflicting demands; however, differentiated exploratory and exploitative activities need to be mobilized, coordinated, integrated, and applied. Based on this idea, we delineate formal and informal senior team integration mechanisms (e.g., contingency rewards and social integration) and formal and informal organizational integration mechanisms (e.g., cross-functional interfaces and connectedness) and examine how they mediate the relationship between structural differentiation and ambidexterity. Overall, our findings suggest that the previously asserted direct effect of structural differentiation on ambidexterity operates through informal senior team (i.e., senior team social integration) and formal organizational (i.e., cross-functional interfaces) integration mechanisms. Through this richer explanation and empirical assessment, we contribute to a greater clarity and better understanding of how organizations may effectively pursue exploration and exploitation simultaneously to achieve ambidexterity.
Processing of Pro–Brain Natriuretic Peptide Is Suppressed by O-Glycosylation in the Region Close to the Cleavage Site
Authors: Semenov Alexander G , Postnikov Alexander B , Tamm Natalia N , Seferian Karina R , Karpova Natalia S , Bloshchitsyna Marina N , Koshkina Ekaterina V , Krasnoselsky Mihail I , Serebryanaya Daria V , Katrukha Alexey G
Published: January 2009

Background: Processing of the brain natriuretic peptide (BNP) precursor, proBNP, is a convertase-dependent reaction that produces 2 molecules—the active BNP hormone and the N-terminal part of proBNP (NT-proBNP). Although proBNP was first described more than 15 years ago, very little is known about the cellular mechanism of its processing. The study of proBNP processing mechanisms is important, because processing impairments could be associated with the development of heart failure (HF).

Methods: The biochemical properties of recombinant proBNP and NT-proBNP and the same molecules derived from the blood of HF patients were analyzed by gel-filtration chromatography, site-directed mutagenesis, and different immunochemical methods with a panel of monoclonal antibodies (MAbs).

Results: Part of the proBNP molecule (amino acid residues 61–76) located near the cleavage site was inaccessible to specific MAbs because of the presence of O-glycans, whereas the same region in NT-proBNP was completely accessible. We demonstrated that a convertase (furin) could effectively cleave deglycosylated (but not intact) proBNP. Of several mutant proBNP forms produced in a HEK 293 cell line, only the T71A variant was effectively processed in the cell.

Conclusions: Only proBNP that was not glycosylated in the region of the cleavage site could effectively be processed into BNP and NT-proBNP. Site-directed mutagenesis enabled us to ascertain the unique suppressing role of T71-bound O-glycan in proBNP processing.
Analytic and Clinical Utility of a Next-Generation, Highly Sensitive Cardiac Troponin I Assay for Early Detection of Myocardial Injury
Authors: Kavsak Peter A , MacRae Andrew R , Yerna Marie-Jeanne , Jaffe Allan S
Published: January 2009

Background: Improvements in cardiac troponin (cTn) assays have increased the rapidity with which clinicians can identify patients with changing cTn concentrations (rise or fall) indicative of acute myocardial injury. The aim of the present study was to characterize a new, high-sensitivity cTnI (hs-cTnI) assay and examine whether increased sensitivity can result in still earlier detection of evolving injury.

Methods: We determined the limit of detection, precision profiles, and preliminary estimates of the 99th percentile for the Beckman Coulter hs-cTnI assay in 125 healthy individuals (age <55 years, 54% male). We compared AccuTnI® and hs-cTnI to assess whether change criteria for early concentration changes (i.e., ≥3SD for low concentrations and 20% difference for concentrations >0.10 μg/L) were exceeded in the first 2 specimens (median time between specimens, 1 h; 25th–75th percentile, 1–3 h) from subjects with symptoms suggestive of cardiac ischemia (n = 290).

Results: The limit of detection for the hs-cTnI assay was 2.06 ng/L, and the 20% CV and 10% CV concentrations were 2.95 and 8.66 ng/L, respectively. The preliminary 99th percentile estimates in lithium heparin, serum, and EDTA plasma were 9.20, 8.00, and 8.60 ng/L, respectively. In 108 patients with myocardial injury based on the peak AccuTnI concentration, applying the change criteria on the 2 earliest specimens identified 81% (95% CI 73%–88%) of patients using the hs-cTnI assay compared to 62% (53%–71%) using the AccuTnI assay (P < 0.001).

Conclusions: Although more extensive validation studies are required, this Beckman Coulter hs-cTnI assay appears to detect patients with evolving myocardial injury earlier.
Co-expression of 9-O-acetylated sialoglycoproteins and their binding proteins on lymphoblasts of childhood acute lymphoblastic leukemia: an anti-apoptotic role
Authors: Mukherjee Kankana , Chava Anil K. , Bandyopadhyay Suman , Mallick Asish , Chandra Sarmila , Mandal Chitra
Published: January 2009

Enhanced levels of 9-O-acetylated sialoglycoproteins (Neu5,9Ac2GPs) as disease-associated molecules was reported to act as signaling molecules for promoting survival of lymphoblasts in childhood acute lymphoblastic leukemia (ALL). Here, we searched for potential physiological ligands for Neu5,9Ac2GPs that could be involved in modulating the survival of lymphoblasts. Accordingly, we examined the presence of binding proteins for Neu5,9Ac2GPs on cell lines and primary cells of patients with B- and T-ALL, at presentation of the disease. Peripheral blood mononuclear cells from normal healthy donors and cells from myeloid leukemia patients were used for comparison. Neu5,9Ac2GPs-binding proteins (BPs) were specifically detected on the surface of both T- and B-ALL-lymphoblasts and ALL-cell lines along with the consistent presence of Neu5,9Ac2GPs. The Neu5,9Ac2GPs and BPs also co-localized on the cell surface and interacted specifically in vitro. Apoptosis of lymphoblasts, induced by serum starvation, was reversed in the presence of purified Neu5,9Ac2GPs due to possible engagement of BPs, and the anti-apoptotic role of this interaction was established. This is the first report of the presence of potential physiological ligands for disease-associated molecules like Neu5,9Ac2GPs, the interaction of which is able to trigger an anti-apoptotic signal conferring a survival advantage to leukemic cells in childhood ALL.
Providing Battlespace Information to Reduce Uncertainty: Will More Information Lead to Better Plans?
Authors: Thunholm Peter
Published: January 2009

One basic assumption behind network-centric warfare (NCW) is that increased supply of information will reduce battlespace uncertainty and increase decision quality. The purpose of this study was to test this assumption. Swedish army captains formed 16 brigade-level planning teams and performed in a realistic planning task. Eight teams planned with access to NCW-similar (abundant) information on the enemy situation, and 8 teams planned using the information supply of today. Results showed a significant reduction in perceived uncertainty for the NCW-condition teams but no substantial differences in plan quality, plan confidence, plan variability, or planning time between the two conditions. These results indicate that even though more information may result in less perceived uncertainty among future military decision makers, an increased information supply needs to be coupled with changes in doctrine and training to provide a maximum benefit to the military planner.
Effects of Automatic Detection on Dynamic Decision Making
Authors: Gonzalez Cleotilde , Thomas Rickey P.
Published: January 2009

The usefulness of the dual-process theory of automaticity to dynamic decision-making tasks is unclear. Dynamic decision making is characterized by multiple, diverse, and interrelated decisions that are often constrained by time limitations and workload. We investigated the relevance of this theory in a compound task consisting of multiple, dynamic components. In the first experiment, we reproduced the original findings that shaped the theory in a dynamic visual search task. In the second experiment, we added a decision-making component. The results replicated the original findings and extended them to decision-making components. Working under consistent-mapping conditions in the visual search component led to more accurate decision making despite variability in the decision-making conditions. Likewise, working under varied-mapping conditions in the visual search component led to poorer decision making, particularly under high workload. The implications of these results to real-world dynamic tasks are discussed.
"Beating Plowshares into Swords": The Colorado River Delta, the Yellow Peril, and the Movement for Federal Reclamation, 1901–1928
Authors: Boime Eric
Published: January 2009

This article examines the intersections of race, nationalism, and water conservation policy. Such relationships, it argues, are particularly pronounced in the history of the Colorado River Delta, a border region and an arid region, especially in the discourse surrounding the international allocation of the river. It focuses on the intellectual underpinnings of federal reclamation leaders and their subscription to the tenets of the idea of "yellow peril," with special reference to Chinese and Japanese immigrant farmers along the U.S.-Mexican border. While the reclamation movement has received considerable scrutiny, the geopolitical views informing it have been largely overlooked. The unexamined writings of George Maxwell, in particular, present a new perspective on the major architect of the National Reclamation Act, one of the region's most far-reaching and consequential pieces of legislation.
A Bolt from the Blue? New Evidence on the Japanese Navy and the Draft Understanding Between Japan and the United States, April 1941
Authors: Mauch Peter
Published: January 2009

This article reproduces in its entirety a recently discovered document pertaining to the Draft Understanding between Japan and the United States that establishes the existence of hitherto unknown communication between the Imperial Japanese Navy and Ambassador Nomura Kichisaburō. It challenges the long-standing historical consensus that Nomura worked independently of Tokyo in preparing the Draft Understanding. It reassesses Nomura's role in the confused process that led the Japanese government to conceive of the Draft Understanding as an American proposal and stresses the extent to which Navy Minister Oikawa Koshirō was responsible for bringing the Draft Understanding to the point that it actually offered a chance at rapprochement. Finally, it investigates Oikawa's supine failure to act on his true responsibilities. In short, this article revises our understanding of a fateful step on the Japanese navy's path to Pearl Harbor.
Development and application of a rapid amphipod reproduction test for sediment-quality assessment
Authors: Mann Reinier M. , Hyne Ross V. , Spadaro David A. , Simpson Stuart L.
Published: January 2009

Melita plumulosa is an epibenthic, detritivorous amphipod native to eastern Australia that has been adopted as a test organism for toxicity evaluations of contaminated estuarine sediments. In the present study, a 13-d amphipod reproduction test was developed that encompasses gametogenesis, fertilization, and embryo development before hatching. The primary endpoints for the test are fecundity (measured as the number of embryos per individual surviving female) and a fecundity index (fecundity multiplied by the stage of embryo development). This new test has been employed to scrutinize the sediments from a metal-contaminated coastal lagoon. Lake Macquarie (NSW, Australia) is a large, saltwater lagoon that has received metal pollution over many decades, leading to a concentration gradient of trace metals, including Pb, Zn, Cd, and Cu, in the sediments. Within one of the northern bays (Warners Bay), the concentrations of these metals either border on or exceed sediment quality guideline values prescribed by Australian and New Zealand Guidelines for Fresh and Marine Water Quality. In trials with the 13-d amphipod reproduction test, Warners Bay sediments significantly reduced fecundity in the test species. Subsequent tests with clean sediments spiked singly with Pb, Zn, or Cu indicated that no single metal was responsible for the observed toxicity in the field sediments. However, sediments spiked with various combinations of Pb, Zn, Cd, and Cu indicated that Zn in combination with one or more of the other metals was responsible for the reproductive toxicity observed in Warners Bay sediments. In all these tests, measured metal concentrations in overlying water and pore water were low, thus confirming that the observed effects on reproduction could be attributed to dietary exposure to metals.
Triggers, Flashbacks, and Fantasia: Intrusive Death Imagery following Homicide Loss
Authors: Blakley Theresa L.
Published: January 2009

Psychological trauma following the murder of a loved one can be tormenting for survivors who involuntarily re-experience their loss in gruesome, sensory-laden images from both witnessed and imagined scenes of the violent death. Intrusive images and cognitions of the event, often experienced in the acute aftermath of homicide, can also be triggered throughout the lifetime of persons suffering traumatic loss. This article differentiates and explores traumagenic re-experiencing phenomena by two types: flashback imagery of the literal event as witnessed by the survivor and non-witnessed imagery that can be abstract, fantastical representations of the violent death scene. Both types are described, compared, and contrasted against the backdrop of the author's own experience of traumata following the murder of her husband. Re-experiencing imagery is discussed as a primary distressor for homicide-loss survivors. Implications for practice point to aiding survivors in developing safety, insight and mastery over disquieting, intrusive imagery of violent loss.
Facial attractiveness: Variation, adaptiveness and consequences of facial preferences
Authors: Kościński Krzysztof
Published: January 2009

This review embraces the following topics: intra- and inter-populational variation of facial preferences, relationship between facial attractiveness and mate value, biological and social effects of the perception of facial attractiveness, credibility of the adaptive perspective on facial preferences, and the phylogeny of facial attractiveness. Its main conclusions are as follows: (1) Many sources of inter-individual variation in assessments of facial attractiveness have been identified, e.g., the age, sex, biological quality, physiological state, personality, and living situation of the judge, as well as previously observed faces, physical similarity of the focal face to the judge's face, and acquaintance with and knowledge of the face owner. (2) Inter-populational consistency in perception of facial attractiveness is substantial and possesses both a biological and a cultural basis. (3) Facial attractiveness is a reliable cue to biological quality of the face owner, e.g., better parasite resistance, physical fitness, reproductive fitness, longevity, less mutational load, higher intelligence and better mental health. (4) Facially attractive people have more sexual partners, marry at a younger age, and remain single less frequently. Thereby, they have higher reproductive success than unattractive individuals. (5) As a whole, research supports the thesis that facial preferences are adaptive, that is, they evolved during the course of biological evolution because they assisted an individual in choosing a mate with good genes or a good personality.
Non-Chemical Control of Some Important Pests of Sweet Cherry
Authors: Andreev Radoslav , Kutinkova Hristina , Baltas Konstantinos
Published: January 2009

Non-Chemical Control of Some Important Pests of Sweet Cherry

Some non-chemical insecticides were tested for efficacy of control of fall webworm,Hyphantria cunea(Drury), and of cherry weevil,Rhynchites auratus(Scop.) in the laboratory and black cherry aphid,Myzus cerasi(Fabr.) under field conditions. Hendreson & Tilton formula was applied for evaluation of efficacy. NeemAzal T/S (azadirahtin) at the concentration 0.5% and Naturalis (Beauveria bassiana) used at 0.2% or 0.3% have shown the best results against black cherry aphid. Good results were also obtained with Pyrethrum FS (pyrethrin + sesame oil + soft potassium soap) used at 0.05% or 0.1%, with NeemAzal T/S at 0.3%, PreFeRal WG (Paecilomyces fumosoroseus) at 0.2% and with Naturalis at 0.1%. The effect of PreFeRal WG, applied at 0.1% was unsatisfactory. Against the fourth instar larvae of fall webworm, excellent results were noted for Pyrethrum (0.05% and 0.1%) and Naturalis (0.1% and 0.2%). Very good effects were also obtained with the BMP 123WP (Bacillus thuringiensis), used in concentration of 0.1%. NeemAzal T/S - 0.5% had still good, albeit lower, efficacy. Against the cherry weevil only Pyrethrum FS was tested. This insecticide resulted in a very good efficacy, when used at the concentration 0.1% and still satisfactory - at 0.05%.
Combination of Mating Disruption and Granulosis Virus for Control of Codling Moth in Bulgaria
Authors: Kutinkova Hristina , Samietz Jörg , Dzhuvinov Vasiliy
Published: January 2009

Combination of Mating Disruption and Granulosis Virus for Control of Codling Moth in Bulgaria

An application of mating disruption by use of Ecodian CP dispensers (ISAGRO, Italy) in combination with the granulosis virus product Carpovirusine 2000 (Arysta LifeScience, France) against Codling moth (CM), Cydia pomonella, was tested near Plovdiv, Central South Bulgaria. In 2007, the method was applied in an orchard where in the previous year fruit damage reached 18.7% and the CM population was high, as indicated by 3.83 diapausing larvae per tree. Carpovirusine was applied 11 times in the trial plot in combination with Ecodian CP dispensers installed twice during the season. Before harvest, fruit damage in the trial plot amounted to 0.9% and the overwintering population in autumn 2007 was only 0.46 larvae per tree. At the same time in the reference orchard, where 15 insecticide treatments were applied during the season, fruit damage before harvest reached 12.3% and the hibernating population was 7.97 larvae per tree. So, it has been confirmed that combination of both methods might be an effective tool for control of codling moth in the orchards with high population density and resistance to conventional insecticides. This study is being continued.
Patient Screening by a Physical Therapist for Nonmusculoskeletal Hip Pain
Authors: VanWye William R
Published: January 2009

Background and Purpose

Mechanical hip pain and disease-based hip pain can have similar signs and symptoms, thereby presenting a differential diagnostic challenge for clinicians. Hip pain is a common complaint addressed by physical therapists; therefore, it would be advantageous for them to be knowledgeable about differential diagnosis for hip pain, so that they can screen for possible serious conditions outside the realm of physical therapist practice and make the appropriate referral.

Case Description

A 77-year-old man was referred for physical therapy by his primary care physician (PCP) with diagnoses of lumbar spine and left hip osteoarthritis and possible trochanteric bursitis. After the examination, the physical therapist determined that the patient should return to his PCP for further testing. Findings leading to this conclusion were pain severity out of proportion to the reported injury, the presence of night pain, a positive “sign of the buttock,” and empty end feels of all hip joint motions, which represented a noncapsular pattern of joint restriction.

Outcomes

The patient was diagnosed later with primary lung adenocarcinoma with widespread metastases. A computerized tomography scan of the left hip revealed a metastatic lesion at the left proximal femur.

Discussion

Physical therapists’ ability to adequately screen for conditions requiring examination by a physician can lead to a more timely diagnosis of serious medical conditions. Investigators have found published descriptions of end feels, capsular versus noncapsular patterns of restriction, and the sign of the buttock to be beneficial screening tools for use in people with hip, pelvis, or lumbar spine pain.
Suspected venous air embolism in three horses
Authors: Pellegrini‐Masini A. , Hurtado I. Rodriguez , Stewart A. J. , Divers T. J.
Published: January 2009

Venous air embolism was suspected in 3 hospitalised horses on the basis of an inadvertently open jugular venous line. Subsequently the 3 horses developed clinical signs including cardiovascular collapse, cardiac dysrhythmia, pulmonary oedema, behavioural abnormalities and neurological signs consistent with central nervous system injury. Treatment included intranasal oxygen therapy, i.v. fluid administration and anti‐inflammatory therapy. Specific therapy aimed at treating air embolism in man is reviewed, with pertinent therapy potentially applicable to horses emphasised.
Quantitative Evaluation of Fully Actuated versus Nonactuated Coordinated Phases
Authors: Day Christopher M. , Smaglik Edward J. , Bullock Darcy M. , Sturdevant James R.
Published: January 2009

Intersections on coordinated arterials typically run in a semiactuated mode, where the end of green for the coordinated phases is fixed in time. During cycles when demand for the coordinated phases is low, the intersection tends to become idle while vehicles wait on minor movements. Actuating a portion at the end of the coordinated phase enables the controller to allocate the green time in response to demand for the coordinated movement. Green time is reallocated to other phases when demand for the coordinated movement is low but is retained by the coordinated movement when demand is high. The operational impacts of actuating the last 9.6 to 11.6 s of the coordinated phases (10% of cycle) at an actuated intersection are investigated by using cycle-by-cycle calculations of measures of effectiveness. The use of fully actuated instead of nonactuated coordinated phases can better balance volume-to-capacity ratios and decrease split failures for minor street movements without major impacts on progression through the coordinated movements. It is recommended that agencies consider actuating coordinated phases to provide robust control that more effectively responds to changing traffic conditions.
Integration of Real-Time Pedestrian Performance Measures into Existing Infrastructure of Traffic Signal System
Authors: Hubbard Sarah M. L. , Bullock Darcy M. , Day Christopher M.
Published: January 2009

Transportation system management requires balancing the needs of many users and multiple transportation modes. Historically, traffic engineers have relied on short-term engineering studies and intuition to manage traffic signal systems. The broad consensus in the traffic engineering community is that real-time performance measures would enable better operations. Motivation and means are presented to provide real-time pedestrian performance measures using existing controller and vehicle detection technology. Applicable pedestrian service models are identified, and procedures for collecting data for pedestrian performance measures are recommended. The resulting pedestrian performance measures can be presented in an easy-to-interpret visual format that provides a valuable tool for assessing and comparing pedestrian service. Pedestrian service may be compared at different crosswalks in the jurisdiction for prioritization purposes, or at the same crosswalk under different conditions. The proposed pedestrian performance measures may be used in conjunction with existing vehicle performance measures, resulting in an integrated approach to assessing the level of service for vehicles and pedestrians under different conditions and for different signal timing plans.
Streamlined Strategies for Faster, Less Traffic-Disruptive Highway Rehabilitation in Urban Networks
Authors: Lee Eul-Bum , Choi Kunhee , Lim Seungwook
Published: January 2009

The need for faster, less traffic-disruptive rehabilitation for aging highway infrastructure is an emerging concern for many state highway agencies. In response to this concern, the California Department of Transportation (Caltrans) launched the Long-Life Pavement Rehabilitation Strategies (LLPRS) program in 1998 to rebuild 2,800 lane kilometers of high-volume urban freeway with premium pavements that will last 30+ years and require minimal maintenance over their service life. This paper presents innovative strategies and technologies for achieving faster project completion with less traffic disruption as applied on three experimental LLPRS projects. The research team and the Caltrans project team used Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software from the initial planning and design stages to implement the most economical rehabilitation strategies for the projects. The postconstruction analysis of all three LLPRS projects, made with data collected during construction, revealed a close match with the preconstruction schedule estimate generated by CA4PRS, validating the software's scheduling reliability. Incentive-disincentive contractual provisions proved effective for shortening project duration on all three LLPRS projects, which were time critical because of their heavy traffic volume. Resultant traffic data demonstrate the importance of a public outreach campaign that convinced motorists to use alternative routes or to adjust their commuting modes, resulting in significantly lower traffic demand in the construction work zone. The strategies and lessons addressed in this paper will help state highway agencies and contractors maximize construction productivity for early project completion and minimize inconvenience to the traveling public.
Evaluation of Dynamic Cone Penetration Quality for Cohesive Soil Embankment Construction
Authors: Larsen Brett W. , White David J. , Jahren Charles T.
Published: January 2009

A pilot project at US-34 in Iowa recently required the use of a new quality control (QC) and quality assurance (QA) specification involving dynamic cone penetration (DCP) testing in concert with conventional moisture and density testing. The contractor's QC test results were verified with occasional QA testing by Iowa State University and the Iowa Department of Transportation. Cone penetration testing and laboratory unconfined compressive strength testing were conducted on samples obtained on natural fill material before excavation and afterwards on the compacted fill to evaluate the performance properties of the final product. The research findings documented in this paper focus on (a) statistical comparisons between contractor QC and independent QA test data, (b) statistical analysis of the contractor QC data, and (c) evaluation of the performance of a completed embankment. The study findings show that the DCP can be used for QC and QA testing for cohesive soils to evaluate stability and vertical uniformity.
Reconstruction of a Damaged Steel Beam Bridge Using an Overhead Support System
Authors: Hill James J.
Published: January 2009

Reconstruction of a bridge damaged by a backhoe on Interstate 494 and Xerxes Avenue in Minneapolis, Minnesota, in 2006 is discussed. The backhoe was extended above the clearance height of the bridge and, after extensively damaging the first five beams, became hung up under the bridge. The backhoe bucket had to be cut off before the truck and backhoe could be removed from under the bridge. The conventional method of supporting a bridge during reconstruction is reviewed and is then compared with the unique system that was used to support the remaining steel beams during reconstruction. The main design features and actual field methods are highlighted as well as a special lifting capability that was used to deal with a difficult field problem that arose.
Cold Curving Steel Bridge Girders
Authors: Gergess Antoine N. , Sen Rajan
Published: January 2009

Horizontally curved steel girders are extensively used in bridge construction. An overview on a new, innovative cold bending technique for curving steel girders, specifically developed to meet the tight construction tolerance requirements of the Miami, Florida, Metromover, is presented. The curving procedure used by the fabricator was retained and detailed analyses were developed to provide closed-form solutions relating loads to deformation for curving symmetrical, asymmetrical, stiffened, and unstiffened girders. This eliminates the trial-and-error nature of the operation in the steel shop. Limits are imposed on the maximum load and corresponding plastic strain to prevent damage. Numerical examples illustrate the application of the proposed method and suggestions for future work are made on how cold bending may be adapted for bridge use.
Reliability of Travel Time
Authors: Bogers Enide A. I. , Van Lint Hans W. C. , Van Zuylen Henk J.
Published: January 2009

The reliability of the travel time on a route is widely regarded as one of the dominant factors affecting the route and departure time choices of travelers. There is still a lack of consensus on the quantitative measures that best reflect travel time reliability. This paper addresses this question from a traveler's point of view. It was concluded from a large stated preference-revealed preference route choice experiment that a measure of the asymmetry of a travel time distribution (λskew) was an important reliability measure. Put simply, people prefer a route that is usually fast but sometimes quite costly over a route that can have any travel time over a long range. In terms of reliability there is a discrepancy between user-optimal choices and system-optimal choices, because the recent literature reveals that skewed travel time distributions may yield much higher (collective) costs than symmetric distributions. Although the results indicate that the degree of skew in the travel time distribution of a route largely affects travel choices, it is strongly argued that there is no one best measure, because what can be regarded as “best” is contingent on the goal that must be reached. In line with this view, it was found in more detailed analyses that travel information and travel purpose influenced travelers’ route choices. Further research should focus on elaborating the contingency view and on working with more individual-based reliability measures for route choice situations.
Hybrid Choice Modeling of New Technologies for Car Choice in Canada
Authors: Bolduc Denis , Boucher Nathalie , Alvarez-Daziano Ricardo
Published: January 2009

In the past decade, a new trend in discrete choice modeling has emerged: psychological factors are explicitly incorporated to enhance the behavioral representation of the choice process. In this context, hybrid models expand on standard choice models by including attitudes and perceptions as latent variables. The complete model is composed of a group of structural equations describing the latent variables in terms of observable exogenous variables and a group of measurement relationships linking latent variables to certain observable indicators. Although the estimation of hybrid models requires the evaluation of complex multidimensional integrals, simulated maximum likelihood is implemented to solve the integrated multiple-equation model. This study empirically evaluates the application of hybrid choice modeling to data from a survey conducted by the Energy and Materials Research Group (Simon Fraser University, 2002 and 2003) of the virtual personal vehicle choices made by Canadian consumers when they are faced with technological innovations. The survey also includes a complete list of indicators that allows the application of a hybrid choice model formulation. It is concluded that the hybrid choice model is genuinely capable of adapting to practical situations by including latent variables among the set of explanatory variables. The incorporation of perceptions and attitudes in this way leads to more realistic models and gives a better description of the profile of consumers and their adoption of new automobile technologies.
Accessibility, Travel Behavior, and New Urbanism
Authors: Joh Kenneth , Boarnet Marlon G. , Nguyen Mai Thi , Fulton William , Siembab Wally , Weaver Susan
Published: January 2009

The proponents of new urbanism have claimed that neotraditional urban designs promote walking, reduce automobile dependence, and improve the quality of life for residents. However, the existing research on land use and travel behavior has not been able to support or invalidate these claims adequately because of data and methodological limitations. This research aims to probe further the complex relationship between the built environment and travel behavior and test the claims made by new urbanists by analyzing travel data obtained from travel surveys and diaries for 16 mixed-use centers (i.e., new urbanist and neotraditional) and auto-oriented corridors (i.e., postwar suburb) in the South Bay region of Los Angeles County, California. All individual trips, driving trips, and walking trips were regressed on selected sociodemographic and attitudinal variables to see if there were significant differences in walking and driving trips between mixed-use centers and auto-oriented corridors. The results both support and challenge the claims of new urbanists: although there are no discernible differences in individual driving trips between mixed-use centers and auto-oriented corridors, a higher number of individual walking trips are reported in mixed-use centers. The findings of the study suggest that aspects of the built environment, as well as attitudinal factors, influence travel behavior–in particular, walking behavior–although further research needs to be conducted in this area to make informed policy decisions pertaining to transportation and land use.
How Do Commuters Know When to Leave Home?
Authors: Senk Petr , Kitamura Ryuichi
Published: January 2009

A psychological research method, protocol analysis, was applied to gain insight into the decision-making process underlying repeated departure time choice for travel on a road network with stochastic travel times. The focus of the study is on the comprehension of information perception, processing, storage, and retrieval. The results showed that commuters do not think as depicted by rational choice theory. Preference ordering or comparison of outcomes is rarely performed, and travel time and its variation are, in principle, not considered. The analysis of verbalized decisions indicates that although the observed behavior differs greatly from subject to subject, the elements stored in and recalled from memory during decision making are nearly the same for all subjects. These elements are the departure and arrival times on the previous day and long-remembered good or bad experiences with a given departure time. These findings suggest that the general framework that can be used to describe departure time decision making is closer to models of adaptive behavior than to normative models of rational choice.
Urban Form, Individual Spatial Footprints, and Travel
Authors: Fan Yingling , Khattak Asad J.
Published: January 2009

Physical planning can benefit from deeper insight into the space-use options that individuals have. This paper examines how individuals’ uses of space are related to urban form factors at their residences, after controlling for traffic congestion, weather, and individual or household characteristics. The behavioral data analyzed came from the 2006 Greater Triangle Region Travel Study in North Carolina. Individuals’ uses of space were measured by daily activity space–the minimum convex polygon that contains all the daily activity locations–and daily travel distance, and were estimated by the use of spatial regression models. The results showed that the residents of densely developed neighborhoods with more retail stores and better-connected streets generally have a smaller area of daily activity space and a shorter daily travel distance. In addition, urban form factors were compared in terms of their importance in explaining individuals’ space-use behavior. It was found that retail mix and street connectivity are key factors relating to individuals’ uses of space, whereas building density was less important. The findings shed light on possible land use solutions toward the better coordination of services in space.
Nonnormality of Data in Structural Equation Models
Authors: Gao Shengyi , Mokhtarian Patricia L. , Johnston Robert A.
Published: January 2009

With the use of census block group data on sociodemographics, land use, and travel behavior, the cutoffs suggested in the literature for trustworthy estimates and hypothesis-testing statistics were tested, and the efficacy of deleting observations as an approach to improving multivariate normality in structural equation modeling was evaluated. It was found that the deletion of enough cases to achieve multivariate normality yielded results that were substantively different from those for the full sample and required that 17% of the sample be discarded. Alternatively, after only a few true outliers were deleted (0.8% of the sample), the measures of uni-variate and multivariate nonnormalities fell into the acceptable range for maximum likelihood estimation to be appropriate. The pursuit of a multivariate normal distribution by the deletion of observations should be consciously weighed against the loss of model power and generalizability in the interpretation of the results. That is, the analyst should proactively find the balance between the two extremes of (a) a model on the full sample that is unreliable because of extreme nonnormality and (b) a model on a sample that has discarded so many cases to achieve multivariate normality that it is no longer fully representative of the desired population. It is further argued that the process of finding that balance should be exposed to the audience rather than ignored or suppressed.
Social Activities and Travel Demand
Authors: Molin Eric , Arentze Theo , Timmermans Harry J. P.
Published: January 2009

Social activities are responsible for an important share of trips conducted by individuals. This paper contributes to a rapidly increasing stream of transportation research into individuals’ choice of social relations and trips made to maintain their social relations. A method that was used to collect data on ego-centered social networks in a large-scale survey conducted in the Netherlands in the late 1980s is described, and a model-based framework for analysis of these data is proposed. The framework consisted of a set of linked regression and choice models for analysis and prediction in a coherent fashion of the travel demands resulting from a chain of decisions, including the size and composition of the social network and the travel time and contact frequency related to each member of the network. The results indicate that the sociodemographic attributes of an individual have only a modest influence on network size and a stronger impact on the choice of relationship type, travel time, and contact frequency. Furthermore, significant relationships exist among these social network variables. It was concluded that the framework provides a straightforward and useful way to analyze social network data and identify fruitful directions for future research.