bluuebunny/crossref_metadata_2025 huggingface dataset:
Peto's paradox and human cancers
Authors: Noble Robert , Kaltz Oliver , Hochberg Michael E.
Published: June 2015

Peto's paradox is the lack of the expected trend in cancer incidence as a function of body size and lifespan across species. The leading hypothesis to explain this pattern is natural selection for differential cancer prevention in larger, longer lived species. We evaluate whether a similar effect exists within species, specifically humans. We begin by reanalysing a recently published dataset to separate the effects of stem cell number and replication rate, and show that each has an independent effect on cancer risk. When considering the lifetime number of stem cell divisions in an extended dataset, and removing cases associated with other diseases or carcinogens, we find that lifetime cancer risk per tissue saturates at approximately 0.3–1.3% for the types considered. We further demonstrate that grouping by anatomical site explains most of the remaining variation. Our results indicate that cancer risk depends not only on the number of stem cell divisions but varies enormously (approx. 10 000 times) depending on anatomical site. We conclude that variation in risk of human cancer types is analogous to the paradoxical lack of variation in cancer incidence among animal species and may likewise be understood as a result of evolution by natural selection.
Phylogenomic analysis of natural products biosynthetic gene clusters allows discovery of arseno-organic metabolites in model streptomycetes
Authors: Cruz-Morales Pablo , Kopp Johannes Florian , Martinez-Guerrero Christian , Yáñez-Guerra Luis Alfonso , Selem Mojica Nelly , Ramos-Aboites Hilda , Feldmann Jörg , Barona-Gómez Francisco
Published: June 2015

Natural products from microbes have provided humans with beneficial antibiotics for millennia. However, a decline in the pace of antibiotic discovery exerts pressure on human health as antibiotic resistance spreads, a challenge that may better faced by unveiling chemical diversity produced by microbes. Current microbial genome mining approaches have revitalized research into antibiotics, but the empirical nature of these methods limits the chemical space that is explored.

Here, we address the problem of finding novel pathways by incorporating evolutionary principles into genome mining. We recapitulated the evolutionary history of twenty-three enzyme families previously uninvestigated in the context of natural product biosynthesis inActinobacteria,the most proficient producers of natural products. Our genome evolutionary analyses where based on the assumption that expanded-repurposed enzyme families-from central metabolism, occur frequently and thus have the potential to catalyze new conversions in the context of natural products biosynthesis. Our analyses led to the discovery of biosynthetic gene clusters coding for hidden chemical diversity, as validated by comparing our predictions with those from state-of-the-art genome mining tools; as well as experimentally demonstrating the existence of a biosynthetic pathway for arseno-organic metabolites inStreptomyces coelicolorandStreptomyces lividans, using gene knockout and metabolite profile combined strategy. As our approach does not rely solely on sequence similarity searches of previously identified biosynthetic enzymes, these results establish the basis for the development of an evolutionary-driven genome mining tool that complements current platforms. We anticipate that by doing so real ‘chemical dark matter’ will be unveiled.
Estimating information flow through a memory system: the utility of meta-analytic methods for genetics
Authors: Yildizoglu Tugce , Weislogel Jan-Marek , Mohammad Farhan , Chan Edwin S.-Y. , Assam Pryseley N. , Claridge-Chang Adam
Published: June 2015

Critics of significance testing claim that this statistical framework promotes discrepancies by using arbitrary thresholds (α) to impose reject/accept dichotomies on continuous data, which is not reflective of the biological reality of quantitative phenotypes. Here we explore this idea and evaluate an alternative approach, demonstrating the potential for meta-analysis and related estimation methods to resolve discordance generated by the use of traditional significance tests. We selected a set of behavioral studies proposing differing models of the physiological basis ofDrosophilaolfactory memory and used systematic review and meta-analysis approaches to define the true role of lobular specialization within the brain. The mainstream view is that each of the three lobes of theDrosophilamushroom body play specialized roles in short-term aversive olfactory memory [1-5], but a number of studies have made divergent conclusions based on their discordant experimental findings [6-8]. Multivariate meta-regression models revealed that short-term memory lobular specialization is not in fact supported by the data, and identified the cellular extent of a transgenic driver as the major predictor of its effect on short-term memory. Our findings demonstrate that meta-analysis, meta-regression, hierarchical models and estimation methods in general can be successfully harnessed to identify knowledge gaps, synthesize divergent results, accommodate heterogeneous experimental design and quantify genetic mechanisms.
Resolving microsatellite genotype ambiguity in populations of allopolyploid and diploidized autopolyploid organisms using negative correlations between allelic variables
Authors: Clark Lindsay V. , Drauch Schreier Andrea
Published: June 2015

A major limitation in the analysis of genetic marker data from polyploid organisms is non-Mendelian segregation, particularly when a single marker yields allelic signals from multiple, independently segregating loci (isoloci). However, with markers such as microsatellites that detect more than two alleles, it is sometimes possible to deduce which alleles belong to which isoloci. Here we describe a novel mathematical property of codominant marker data when it is recoded as binary (presence/absence) allelic variables: under random mating in an infinite population, two allelic variables will be negatively correlated if they belong to the same locus, but uncorrelated if they belong to different loci. We present an algorithm to take advantage of this mathematical property, sorting alleles into isoloci based on correlations, then refining the allele assignments after checking for consistency with individual genotypes. We demonstrate the utility of our method on simulated data, as well as a real microsatellite dataset from a natural population of octoploid white sturgeon (Acipenser transmontanus). Our methodology is implemented in the R packagepolysatversion 1.5.
Dynamic changes in replication timing and gene expression during lineage specification of human pluripotent stem cells
Authors: Rivera-Mulia Juan Carlos , Buckley Quinton , Sasaki Takayo , Zimmerman Jared , Didier Ruth A. , Nazor Kristopher , Loring Jeanne F. , Lian Zheng , Weissman Sherman , Robins Allan J. , Schulz Thomas C. , Menendez Laura , Kulik Michael J. , Dalton Stephen , Gabr Haitham , Kahveci Tamer , Gilbert David M.
Published: June 2015

Duplication of the genome in mammalian cells occurs in a defined temporal order referred to as its replication-timing (RT) program. RT changes dynamically during development, regulated in units of 400–800 kb referred to as replication domains (RDs). Changes in RT are generally coordinated with transcriptional competence and changes in subnuclear position. We generated genome-wide RT profiles for 26 distinct human cell types, including embryonic stem cell (hESC)-derived, primary cells and established cell lines representing intermediate stages of endoderm, mesoderm, ectoderm, and neural crest (NC) development. We identified clusters of RDs that replicate at unique times in each stage (RT signatures) and confirmed global consolidation of the genome into larger synchronously replicating segments during differentiation. Surprisingly, transcriptome data revealed that the well-accepted correlation between early replication and transcriptional activity was restricted to RT-constitutive genes, whereas two-thirds of the genes that switched RT during differentiation were strongly expressed when late replicating in one or more cell types. Closer inspection revealed that transcription of this class of genes was frequently restricted to the lineage in which the RT switch occurred, but was induced prior to a late-to-early RT switch and/or down-regulated after an early-to-late RT switch. Analysis of transcriptional regulatory networks showed that this class of genes contains strong regulators of genes that were only expressed when early replicating. These results provide intriguing new insight into the complex relationship between transcription and RT regulation during human development.
Board independence and the quality of board monitoring: evidence from China
Authors: Wu Xiaohui , Li Hui
Published: June 2015

Purpose

– In 2001, the China Securities Regulatory Commission required that at least one-third of the members of corporate boards of directors come from outside the organization. The purpose of this paper is to investigate the impact of this change of regulation on corporate governance in China. In particular, the authors examine whether the increase in the proportion of outsider directors can increase the monitoring quality of the board.

Design/methodology/approach

– The basic empirical methodology is a logit regression in which the dependent variable is a binary variable that represents one of the three “negative events” identified as the indicators of poor monitoring quality. The independent variables are firm-level control variables.

Findings

– Using Chinese stock data from 1999 to 2005, the authors find that the resulting increase in board independence has reduced the occurrence of connected transactions and violations such as financial statement fraud, illegal insider trading, and asset misappropriation. However, this positive effect of board independence is not uniform across firms. The authors show that a higher degree of fundamental uncertainty in a firm impedes the effectiveness of board independence. The authors also document that the level of board independence is positively associated with firm performance, as measured either in stock market return or accounting return.

Originality/value

– In this paper, the authors aim to investigate the effectiveness of outsider directors in a more direct way than has previous research. The authors measure the improvement in the quality of board monitoring by the reduction of the likelihood of those corporate events that could reduce firms’ value. In particular, the authors examine the relationship between the board independence and the occurrence of “negative” corporate events in China. To the best of the knowledge, this is the first study that explores the link between board independence and the probabilities of these events.
Social CRM, RMO and business strategies affecting banking performance effectiveness in B2B context
Authors: Wongsansukcharoen Jedsada , Trimetsoontorn Jirasek , Fongsuwan Wanno
Published: June 2015

Purpose

– This paper aims to develop structural equation modelling of variables that affect the banking performance effectiveness of Thai Commercial Bank branches in the financial service sector by gathering quantitative data.

Design/methodology/approach

– The population of the study covers all 2,068 Thai Commercial Bank branches in Bangkok, Thailand. This research defined the Thai banks for data collection using stratified sampling (first step) and simple sampling (second step). Primary data were collected using a self-administered survey of 65 managers and 185 marketing officers. In the total sample, 69 (27.6 per cent) of the respondents were male and 181 (72.4 per cent) were female in the Thai Commercial Bank branches. The responses to the questions capturing focal constructs used a seven-point Likert scale. Data were analysed using confirmatory factor analysis and structural equation modelling.

Findings

– It was found that significant relationships existed between social customer relationship management (CRM), relationship marketing orientation (RMO) and business strategies and banking performance effectiveness. The key success factors of social CRM and relationship marketing orientation were found to have indirect influences on banking performance effectiveness through mediation of business strategies. Additionally, the results of this research show that social CRM and RMO have direct and indirect influences on banking performance effectiveness through the mediation of focus strategy or differentiation strategy (p< 0.001).

Practical implications

– Recent development of the digital communications in industrial marketing to achieve firm performance, chief executive officer, management officers and managers could consider setting managing and marketing plans for excellent performance, and long-term relationship by five steps.

Originality/value

– These results add performance effectiveness and long-term relationships with business-to-business (B2B) service industry and bank customers (both retail and public enterprises) to the factors needed to respond to the highly competitive situation at present, which will be even more important with the ASEAN Economic Community in 2015.
The education and professional practice of valuers in South Africa: a critical review
Authors: Mooya Manya Mainza
Published: June 2015

Purpose

– Uniquely among the built-environment professions in the country, professional valuers in South Africa until recently did not require to have a university degree. The vast majority of professional valuers therefore, especially at senior levels, hold the national diploma as the highest academic qualification. There is evidence to suggest that many regard this state of affairs as unsatisfactory. Given the foregoing, the purpose of this paper is to answer two interrelated questions, first, whether South African trained and educated valuers were “competent” and met industry standards, and, second, whether the South African valuation curriculum met international norms.

Design/methodology/approach

– Empirical data for the study were obtained by way of a survey of valuers registered on the South African Council of the Property Valuers Profession (SACPVP) database and a case study of the University of Cape Town’s valuation curriculum. The survey involved the mailing of an online questionnaire, using the “Survey Monkey platform”, to 2,062 individuals, representing the total population of valuers registered with the SACPVP, across all registration categories. A total of 324 individuals, or 15.7 per cent of the target population, responded to the survey.

Findings

– Results from the study on the first question showed that it was professional status and length of experience, rather than academic qualifications, which correlated with competence. In addition, the results suggest that there are grounds for concern regarding proficiency in at least some of the valuation methods across the board. Further, the study revealed significant levels of dissatisfaction amongst employers with the general competence of valuers under their supervision. On the second question, the study concludes that the South African valuation curriculum did not meet international norms in terms of certain criteria.

Practical implications

– The paper recommends a review of the South African valuation curriculum; to allow for a differentiation between the different academic levels, to facilitate a more conceptual approach at the higher levels, and to close the identified gaps in knowledge and skill-sets arising from both a deficient curriculum and a changing industry landscape.

Originality/value

– At a time when attempts are being made to improve standards in the South African valuation profession, the study makes a critical contribution, by identifying areas where the national curriculum is deficient, both in terms of industry requirements and relative to international norms.
Do equity mispricing and management compensation incentives drive bank mergers?
Authors: Doukas John A. , Zhang Wenjia
Published: June 2015

Purpose

– The purpose of this paper is to test whether bank mergers are driven by equity overvaluation and management compensation incentives.

Design/methodology/approach

– To test whether equity mispricing drive bank mergers, the authors employ two alternative price-to-residual income valuation (P/V) measures for bidders and targets while the authors control for their growth prospects with the price-to-book (P/B) (two years before) ratio. The intrinsic value (V) is estimated using the three-period forecast horizon residual income model of Ohlson (1995) and perpetual residual income model that does not rely on analysts’ forecasts of future earnings prospects. The latter measure allows the authors to estimate V for a much larger sample of banks. The empirical analysis is supplemented with a standard event analysis and assessment of the long-term performance of bank mergers subsequent to the announcement date.

Findings

– The evidence shows that bidders are overvalued relative to their targets, especially in equity offer deals. The authors also find that highly valued bidders: are more likely to use stock than cash; are willing to pay more relative to the target market price; are more likely to acquire private than public targets; earn lower announcement-period returns; fail to create synergy gains; experience long-term underperformance; and reward their top managers of with large compensation increases subsequent to mergers.

Originality/value

– This study provides results consistent with the view that behavioral and managerial incentives play an important role in motivating bank mergers.
Corporate Political Connections and Tax Aggressiveness
Authors: Kim Chansog (Francis) , Zhang Liandong
Published: June 2015

This study investigates the relation between corporate political connections and tax aggressiveness. We study a broad array of corporate political activities, including the employment of connected directors, campaign contributions, and lobbying. Using a large hand‐collected data set of U.S. firms' political connections, we find that politically connected firms are more tax aggressive than nonconnected firms, after controlling for other determinants of tax aggressiveness, industry and year fixed effects, and the endogenous choice of being politically connected. Our findings are robust to various measures of political connections and tax aggressiveness. These results are consistent with the conjecture that politically connected firms are more tax aggressive because of their lower expected cost of tax enforcement, better information regarding tax law and enforcement changes, lower capital market pressure for transparency, and greater risk‐taking tendencies induced by political connections.
Parental Separation and Offspring Alcohol Involvement: Findings from Offspring of Alcoholic and Drug Dependent Twin Fathers
Authors: Grant Julia D. , Waldron Mary , Sartor Carolyn E. , Scherrer Jeffrey F. , Duncan Alexis E. , McCutcheon Vivia V. , Haber Jon Randolph , Jacob Theodore , Heath Andrew C. , Bucholz Kathleen K.
Published: June 2015

Background

We examined associations between parental separation during childhood and offspring alcohol involvement, adjusting for genetic and environmental risks specific to parental alcohol (AD) and cannabis/other illicit drug dependence (DD).

Methods

The sample consisted of 1,828 offspring of male twins from the Vietnam Era Twin (VET) Registry, who completed a telephone diagnostic interview. Cox proportional hazards regression analyses were conducted predicting onset of first use, transition from first use to first AD symptom, and transition from first use to AD diagnosis from paternal and avuncular AD and DD history, parental separation, and offspring and family background characteristics. Paternal/avuncular DD/AD was based on the DSM‐III‐R; offspring and maternal AD were based on DSM‐IV criteria.

Results

Paternal DD/AD predicted increased offspring risk for all transitions, with genetic effects suggested on rate of transitioning to AD diagnosis. Parental separation was predictive of increased risk for early alcohol use, but a reduced rate of transition to both AD symptom onset and onset of AD. No interactions between separation and familial risk (indexed by paternal or avuncular DD/AD) were found.

Conclusions

Findings highlight the contribution of both parental separation and paternal substance dependence in predicting timing of offspring alcohol initiation and problems across adolescence into early adulthood.
Classical and Atypical Fibrodysplasia Ossificans Progressiva in India
Authors: Madhuri Vrisha , Santhanam Mona , Sugumar Legasri K , Rajagopal Karthikeyan , Chilbule Sanjay K
Published: June 2015

Fibrodysplasia Ossificans Progressiva (FOP) is a rare debilitating disorder characterized by congenital deformity of the great toes from infancy and postnatal heterotopic ossification. Activating mutations in the activin A receptor type 1 (ACVR1) gene are responsible for the disease. The most common allelic variant leading to FOP is c.617 G>A; p.R206H, however, other alleles have been reported with atypical phenotypes. We report 14 cases presenting to a referral institution in South India over a 3‐year period. The patients were clinically diagnosed based on foot abnormality or abnormal ectopic ossification and were screened for ACVR1. The genetic analysis of ACVR1 identified the recurrent allelic variant in 12 of 14 patients. One of the remaining patients had a previously reported allele c.1067G>A; p.G356D in the 9th exon and the second allele c.983G>A; p.G328E in the 8th exon of ACVR1. The most common recurrent allele c.617 G>A; p.R206H is also the most common in Indian patients with FOP.
Interaction of synchronized dynamics in cortex and basal ganglia in Parkinson's disease
Authors: Ahn Sungwoo , Zauber S. Elizabeth , Worth Robert M. , Witt Thomas , Rubchinsky Leonid L.
Published: June 2015

Parkinson's disease pathophysiology is marked by increased oscillatory and synchronous activity in the beta frequency band in cortical and basal ganglia circuits. This study explores the functional connections between synchronized dynamics of cortical areas and synchronized dynamics of subcortical areas in Parkinson's disease. We simultaneously recorded neuronal units (spikes) and local field potentials (LFP) from subthalamic nucleus (STN) and electroencephalograms (EEGs) from the scalp in parkinsonian patients, and analysed the correlation between the time courses of the spike–LFP synchronization and inter‐electrode EEG synchronization. We found the (non‐invasively obtained) time course of the synchrony strength between EEG electrodes and the (invasively obtained) time course of the synchrony between spiking units and LFP in STN to be weakly, but significantly, correlated with each other. This correlation is largest for the bilateral motor EEG synchronization, followed by bilateral frontal EEG synchronization. Our observations suggest that there may be multiple functional modes by which the cortical and basal ganglia circuits interact with each other in Parkinson's disease: not only may synchronization be observed between some areas in cortex and the basal ganglia, but also synchronization within cortex and within basal ganglia may be related, suggesting potentially a more global functional interaction. More coherent dynamics in one brain region may modulate or activate the dynamics of another brain region in a more powerful way, causing correlations between changes in synchrony strength in the two regions.
Efficacy and safety of pharmacological treatments for acute Lyme neuroborreliosis – a systematic review
Authors: Dersch R. , Freitag M. H. , Schmidt S. , Sommer H. , Rauer S. , Meerpohl J. J.
Published: June 2015

Background and purpose

Our aim was to evaluate the available evidence for pharmacological treatment of acute Lyme neuroborreliosis as a basis for evidence‐based clinical recommendations in a systematic review.

Methods

A systematic literature search of Medline, EMBASE, the Cochrane Library and three trial registries was performed. Randomized controlled trials (RCTs) and non‐randomized studies (NRS) were evaluated. Risk of bias was assessed using the Cochrane risk of bias tools. The primary outcome was ‘residual neurological symptoms’ whilst the secondary outcomes were disability, quality of life, pain, fatigue, depression, cognition, sleep, adverse events and cerebrospinal fluid pleocytosis. The quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Results

After screening 5779 records, eight RCTs and eight NRS were included. Risk of bias was generally high. No statistically significant difference was found between doxycycline and beta‐lactam antibiotics in a meta‐analysis regarding residual neurological symptoms at 4–12 months [risk ratio (RR) 1.27, 95% confidence interval (CI) 0.98–1.63, P = 0.07] or adverse events (RR 0.82, 95% CI 0.54–1.25, P = 0.35). Significantly fewer neurological symptoms for cefotaxime compared with penicillin were found (RR 1.81, 95% CI 1.10–2.97, P = 0.02). Adverse events were significantly fewer for penicillin (RR 0.56, 95% CI 0.38–0.84, P = 0.005).

Conclusions

Evidence regarding pharmacological treatment of acute Lyme neuroborreliosis is scarce and therefore insufficient to recommend preference of beta‐lactam antibiotics over doxycycline or vice versa. However, due to considerable imprecision, relevant differences between treatments cannot be excluded. No evidence suggesting benefits of extended antibiotic treatments could be identified. Further well‐designed trials are needed. Individual treatment decisions should address patients' preferences and individual conditions like prior allergic reactions.
Use of Hydrofluoric Acid Desilicification in the Determination of Highly Siderophile Element Abundances and Re‐Pt‐Os Isotope Systematics in Mafic‐Ultramafic Rocks
Authors: Day James M.D. , Waters Christopher L. , Schaefer Bruce F. , Walker Richard J. , Turner Simon
Published: June 2015

Properly combining highly siderophile element (HSE: Re, Pd, Pt, Ru, Ir, Os) abundance data, obtained by isotope dilution, with corresponding 187Os/188Os and 186Os/188Os measurements of rocks requires efficient digestion of finely‐ground powders and complete spike‐sample equilibration. Yet, because of the nature of commonly used methods for separating Os from a rock matrix, hydrofluoric acid (HF) is typically not used in such digestions. Consequently, some silicates are not completely dissolved, and HSE residing within these silicates may not be fully accessed. Consistent with this, some recent studies of basaltic reference materials (RMs) have concluded that an HF‐desilicification procedure is required to fully access the HSE (Ishikawa et al. (2014) Chemical Geology, 384, 27–46; Li et al. (2015) Geostandards and Geoanalytical Research, 39, 17–30). Highly siderophile element abundance and Os isotope studies of intraplate basalts typically target samples with a range of MgO contents (< 8 to > 18% m/m, or as mass fractions, < 8 to > 18 g per 100 g), in contrast to the lower MgO mass fractions (< 10 g per 100 g) of basalt and diabase RMs (i.e., BIR‐1, BHVO‐2, TDB‐1). To investigate the effect of HF‐desilicification on intraplate basalts, experiments were performed on finely ground Azores basalts (8.1–17 g per 100 g MgO) using a ‘standard acid digestion’ (2:1 mixture of concentrated HNO3 and HCl), and a standard acid digestion, followed by HF‐desilicification. No systematic trends in HSE abundances were observed between data obtained by standard acid digestion and HF‐desilicification. Desilicification procedures using HF do not improve liberation of the HSE from Azores basalts, or some RMs (e.g., WPR‐1). We conclude that HF‐desilicification procedures are useful for obtaining total HSE contents of some young lavas, but this type of procedure is not recommended for studies where Re‐Pt‐Os chronological information is desired. The collateral effect of a standard acid digestion to liberate Os, followed by HF‐desilicification to obtain Re and Pt abundances in samples, is that the measured Re/Os and Pt/Os may not correspond with measured 187Os/188Os or 186Os/188Os.
Histone deacetylase 5 regulates the inflammatory response of macrophages
Authors: Poralla Lukas , Stroh Thorsten , Erben Ulrike , Sittig Marie , Liebig Sven , Siegmund Britta , Glauben Rainer
Published: June 2015

Modifying the chromatin structure and interacting with non‐histone proteins, histone deacetylases (HDAC) are involved in vital cellular processes at different levels. We here specifically investigated the direct effects of HDAC5 in macrophage activation in response to bacterial or cytokine stimuli. Using murine and human macrophage cell lines, we studied the expression profile and the immunological function of HDAC5 at transcription and protein level in over‐expression as well as RNA interference experiments. Toll‐like receptor‐mediated stimulation of murine RAW264.7 cells significantly reduced HDAC5 mRNA within 7 hrs but presented baseline levels after 24 hrs, a mechanism that was also found for Interferon‐γ treatment. If treated with lipopolysaccharide, RAW264.7 cells transfected for over‐expression only of full‐length but not of mutant HDAC5, significantly elevated secretion of tumour necrosis factor α and of the monocyte chemotactic protein‐1. These effects were accompanied by increased nuclear factor‐κB activity. Accordingly, knock down of HDAC5‐mRNA expression using specific siRNA significantly reduced the production of these cytokines in RAW264.7 or human U937 cells. Taken together, our results suggest a strong regulatory function of HDAC5 in the pro‐inflammatory response of macrophages.
A Goodness‐of‐Fit Test for Integer‐Valued Autoregressive Processes
Authors: Schweer Sebastian
Published: June 2015

For autoregressive count data time series, a goodness‐of‐fit test based on the empirical joint probability generating function is considered. The underlying process is contained in a general class of Markovian models satisfying a drift condition. Asymptotic theory for the test statistic is provided, including a functional central limit theorem for the non‐parametric estimation of the stationary distribution and a parametric bootstrap method. Connections between the new approach and existing tests for count data time series based on moment estimators appear in limiting scenarios. Finally, the test is applied to a real data set.
Comparison between Urine Protein: Creatinine Ratios of Samples Obtained from Dogs in Home and Hospital Settings
Authors: Duffy M.E. , Specht A. , Hill R.C.
Published: June 2015

Background

The urine protein:creatinine ratio (UPC) is used to quantify urine protein excretion and guide recommendations for monitoring and treatment of proteinuria.

Hypothesis/Objectives

Home urine samples will have lower UPCs than hospital samples. The objectives were to compare UPCs of samples collected in each setting and to determine whether environment of sample collection might affect staging, monitoring or treatment recommendations.

Animals

Twenty‐four client‐owned dogs.

Methods

Prospective, nonmasked study. Clients collected a urine sample from their dog at home and a second sample was collected at the hospital. Dogs receiving corticosteroids or angiotensin‐converting enzyme inhibitors were excluded, as were those with urine samples of inadequate volume, no protein on dipstick analysis, or active urine sediment. Samples were refrigerated after collection, dipstick and sediment evaluations were completed and each sample was frozen at −80°C within 12 hours. UPCs were performed on frozen samples within 2 months.

Results

From 81 paired samples, 57 were excluded. Of the remaining 24, 12/24 (50%) had higher hospital sample UPCs, 9/24 (38%) had identical UPCs, and 3/24 (12%) had lower hospital UPCs. The UPCs of hospital samples were higher than home samples for the total population (P = .005) and the subset with UPC > 0.5 (P = .001).

Conclusions

Setting and related circumstances of urine collection in dogs is associated with UPC differences; results are usually higher in hospital than in home samples. This difference has the potential to affect clinical interpretation.
Isogeometric Fatigue Damage Prediction in Large-Scale Composite Structures Driven by Dynamic Sensor Data
Authors: Bazilevs Y. , Deng X. , Korobenko A. , Lanza di Scalea F. , Todd M. D. , Taylor S. G.
Published: June 2015

In this paper, we combine recent developments in modeling of fatigue-damage, isogeometric analysis (IGA) of thin-shell structures, and structural health monitoring (SHM) to develop a computational steering framework for fatigue-damage prediction in full-scale laminated composite structures. The main constituents of the proposed framework are described in detail, and the framework is deployed in the context of an actual fatigue test of a full-scale wind-turbine blade structure. The results indicate that using an advanced computational model informed by in situ SHM data leads to accurate prediction of the damage zone formation, damage progression, and eventual failure of the structure. Although the blade fatigue simulation was driven by test data obtained prior to the computation, the proposed computational steering framework may be deployed concurrently with structures undergoing fatigue loading.
Rail-Structure Interaction Analysis of Sliding Slab Track on Bridge
Authors: Lee Kyoung-Chan , Jang Seung Yup , Jung Dong-Ki , Byun Hyung-Kyoon , Park Hyo-Ki , Yang Tae-Sock
Published: June 2015

Continuous welded rail (CWR) on a bridge structure typically experiences a large amount of additional longitudinal axial forces due to longitudinal rail-structure (or track-bridge) interaction under temperature change and train vertical and traction/braking load effect. In order to reduce the additional axial forces, a special type of fastener, such as zero longitudinal restraint (ZLR) and reduced longitudinal restraint (RLR) or rail expansion joint (REJ) should be applied. Sliding slab track system is developed to reduce the effect of rail-structure interaction through the application of a low-frictional sliding layer between slab track and bridge structure. This study presents a track-bridge interaction analysis of the sliding slab track and compares them with conventional fixed slab track on bridges. Various types of span length and longitudinal profiles of bridges are considered in the analysis, which also include multiple continuous spans and extra-dosed bridges. The analysis found that the sliding slab track can reduce the additional axial forces of the continuous welded rail from 80% to 90%, and the difference is more significant for long and continuous span bridge. By the application of the sliding slab track, the use of any other special type of rail fasteners or REJ can be avoided. In addition, span length will not be restricted by the rail-structure interaction effect in planning the railway bridge layout. Continuous span bridge has been usually avoided for railway bridges, but it is preferred for the application of the sliding slab track because the interaction effect can mostly be removed. A continuous span bridge usually has an economical cross-section for the bridge girder, pier and foundation and better dynamic characteristics compared to simple span bridge, and its application eventually will reduce the construction cost of the railway infrastructure.
Using Data Visualization to Analyze Grade Crossing Accidents
Authors: Williams Trefor , Abello James , Betak John , Desimone David
Published: June 2015

The Federal Railroad Administration grade crossing accident database contains numerous interrelated variables. Understanding of how the variables are interrelated can be enhanced using modern visualization techniques. These techniques can allow managers from railroads and government agencies to find complex variables relationships not usually provided by routine statistical analyses. For this research we have developed several dashboards of linked visualizations using the Weave data visualization software [5]. Our visualizations explore various accident types of concern to the railroad industry including trespassing and pedestrian accidents, passenger train accidents, actions of highway users involved in accidents, and the effect of different types of warning devices on grade crossing accidents. In addition, we are currently developing an advanced visualization system that views the accident data as time varying events occurring over a fixed grade crossings topology. This view allows the application of a recent network data abstraction termed “Graph Cards.” We present initial examples of the advanced system that provides a variety of filtering mechanisms to view statistical distributions and their time varying behavior over the grade crossings topology.
Automatic Detection of Corrugation: Preliminary Results in the Dutch Network Using Axle Box Acceleration Measurements
Authors: Li Shaoguang , Núñez Alfredo , Li Zili , Dollevoet Rolf
Published: June 2015

Short pitch corrugation is commonly seen in all kinds of tracks. There is not yet a conclusive explanation in the literature for its initiation and growth mechanisms. In this paper, we use an axle box acceleration (ABA) measurement system to detect corrugation. ABA can be easily implemented in operational trains, providing direct and reliable health monitoring of the track. We have extended a detection algorithm for rail surface local short wavelength defects to also detect short pitch corrugation, which is a continuous defect over the track. A 3D transient FE wheel-track model is employed to find theoretical signature tunes of the wheel-track system response when passing over a short pitch corrugation. Numerical simulations agree with ABA measurement obtained in the Dutch rail network. Based on the signature tune identified, an automatic detection algorithm is developed. Preliminary results with the algorithm are discussed. Field observations show a good potential of the detection algorithm to be used by inframanagers, to detect and monitor corrugation.
Analysis of the Dynamic Behaviour of a Railway Track in Transition Zones With Differential Settlement
Authors: Wang H. , Markine V. L. , Shevtsov I. Y. , Dollevoet R.
Published: June 2015

Transition zones in railway tracks are locations with considerable changes in the vertical stiffness of the rail support. Typically they are located near engineering structures, such as bridges, culverts and tunnels. In such locations, the vertical stiffness of the track support varies, resulting in amplification of the dynamic forces acting on the track, which ultimately leads to deterioration of the vertical track geometry. Also, differential settlement of the track sub-structure on both sides of the transition contributes to the deterioration of the vertical geometry. The deterioration process accelerates with increase of the operational velocities of the passing trains. Finally, all these result in increase of the maintenance efforts on correction of the track geometry in the transition zones.

To analyze the dynamic behavior of transition zones due to the differential settlement, a finite element dynamic model (using explicit integration) of a track transition zone is developed. The model is also accounting for the effect of hanging sleepers. The model is verified against the measurement results performed using the Video Gauge System (VGS). With the developed model, the differential settlement of ballast and soil has been introduced and the effects of this settlement on performance of the track are analyzed. The resulting wheel forces and the dynamic responses of the track components are obtained and analyzed. Special attention has been paid on the stresses of ballast, which is one of the most vulnerable track components in the transition zones. Finally, conclusions on the effect of the various internal and external factors on the degradation process of the track in transition zones are drawn. With the developed model, the differential settlement of ballast and soil is induced and hence, the effects of the differential settlements can be analysed. The contact forces of wheel-rail interaction and the dynamic response of track components are obtained and analysed. Special attention has been paid on the stresses of ballast which are one of the most vulnerable components in the track transition zones. Finally, conclusions on the effect of the various internal and external factors on the degradation process of the track in transition zones are drawn.
In-Plant Testing of a New Multi-Camera Transfer Length Measurement System for Monitoring Quality Control of Railroad Crosstie Production
Authors: Beck B. Terry , Peterman Robert J. , Wu Chih-Hang John , Bodapati Naga Narendra B.
Published: June 2015

Knowledge of transfer length is critical for maintaining continuous production quality in the modern manufacture of prestressed concrete railroad ties. Traditional manual laboratory methods for measuring transfer length are simply not suitable for production operation. They are much too time-consuming to implement, and typically require extensive surface preparation in order to obtain the required surface strain measurements needed for determining the transfer length. In addition, the traditional 95% Average Maximum Strain (95% AMS) method of assessing transfer length from the measured surface strain profile has been shown to possess bias. The accuracy of transfer length assessment using this method is generally influenced by individual operator judgment; therefore, making it unsuitable for use as a reliable production quality-control parameter.

This paper presents recent in-plant testing of a newly developed prototype multi-camera non-contact transfer length measurement system, representing a major improvement over the traditional manual methods. The testing was conducted on concrete railroad ties at a manufacturing facility in North America. Concrete ties tested included those which were manufactured using indented prestressing wire as well as with 7-wire strand. The new device represents a next generation version of the previously successful Laser-Speckle Imaging (LSI) system developed by the authors. The multi-camera system is shown to provide nearly real-time surface strain profile measurements (subsequent to de-tensioning), with surface strain accuracy comparable to the mechanical Whittemore gage device, yet with little or no required surface preparation. Furthermore, with the previously demonstrated Zhao-Lee (ZL) transfer length processing algorithm built into a LabVIEW data acquisition and control interface, the multi-camera system is shown to provide assessments of transfer length within a nominal tolerance of +/− 1.5 inches using as few as six uniformly spaced surface strain measurements. This brings within reach the ultimate goal of providing the railroad tie manufacturer with the ability to measure the transfer length of every tie produced prior to leaving the plant, thereby ensuring that they are within an acceptable tolerance, and providing the means to quickly identify the need to modify production (e.g., concrete mix) if transfer length specifications fall out of desired range.
The Effect of HRWR and AEA on the Air System of Vibrated Concrete
Authors: Ghadban Ahmad , Albahttiti Mohammed , Riding Kyle , Lange David
Published: June 2015

Air entrainment in concrete railroad ties is typically included to prevent freeze-thaw damage. Uniformly-distributed microscopic air voids in concrete ties helps to resist against freeze-thaw. The air entrainment system stability with time after mixing is dependent on a number of factors which include chemical, environmental, and construction related parameters. These resulting differences in the air void system can in turn lead to different performances of concrete under freeze-thaw loading. Vibration is mainly used to consolidate concrete but can also alter the air structure of concrete. This study investigates the effect of different chemical admixtures and rheological properties on the stability of the air system inside vibrated concrete. Form vibration of 75 Hz frequency and 3 g or 10 g peak acceleration was applied to the tested concrete after the lapse of several time durations. This was done to investigate the stability of the air system of concrete as time passes on under different vibration conditions. The testing included slump, unit weight, temperature, rheology and fresh air content before vibration and after vibration for each elapsed time duration. Fresh air content tests showed that the air loss increases linearly with time for almost all mixtures. Concrete rheological properties immediately after mixing were not a good indicator of the concrete air system stability after delayed placement. Tall oil based air entraining agents (AEA) was found to produce slightly lower air instability; however, the differences between AEA were small. The results showed that for precast concrete railroad ties, any instability with time of entrained air should not be a significant problem for precast concrete railroad tie plants if the concrete is placed and consolidated within 30 minutes from mixing at room temperatures.
Investigation and Prediction of Stiffness Increase of Resilient Rail Pad due to Train and Environmental Load in High-Speed Railway
Authors: Kim Eun , Yang Sin Chu , Jang Seung Yup
Published: June 2015

The rail pad stiffness is one of key design parameters of the track structure, affecting the load distribution along the rail and the dynamic behavior of the track. The rail pad stiffness, however, can be increased under accumulated train load and environmental load, i.e., temperature change, due to the nature of resilient rubber. This study investigates the causes and prediction model of the stiffness increase of the resilient rail pads used in the ballasted and concrete slab track in high-speed railway. For this purpose, in-situ rail pads were taken from several sites, and the static and dynamic stiffness was measured. Also, the repeated load test and accelerated heat aging test on new rail pads in the laboratory have been performed. Based on the test data, proposed is a mathematical model for predicting the increase of the rail pad stiffness according to passing tonnage and elevated temperature.
Tracking of Spall Deterioration on Tapered Roller Bearings
Authors: Gonzalez Amy , Tarawneh Constantine , Hu Ping , Turner Joseph A. , Wilson Brent M.
Published: June 2015

Fatigue spall initiation is one of the major modes of premature bearing failure. The spall initiation is often exacerbated by the presence of impurities in the near-surface region (∼400 μm) of the bearing raceways. Once a spall initiates, it can propagate rapidly, leading to abnormal bearing operation and possible catastrophic failure if not detected early. Testing performed at the University of Texas-Pan American (UTPA) has focused on ultrasonically scanned tapered roller bearings found to have inclusion content within 400 μm of the surface of the raceways. These bearings undergo accelerated service life tests in which spall initiation is detected and tracked over time while documenting spall growth. The work presented here provides several study cases that document the spall initiation and propagation on ultrasonically scanned tapered roller bearing components. Results show that spalls generally initiate on locations corresponding to sites of subsurface inclusions, and they grow many times their original size within relatively short operating periods. The study also shows that spalls tend to initiate and propagate at a faster rate on bearing cups (outer rings) than on cones (inner rings).