bluuebunny/crossref_metadata_2025 huggingface dataset:
Senescence and apoptosis: dueling or complementary cell fates?
Authors: Childs Bennett G , Baker Darren J , Kirkland James L , Campisi Judith , van Deursen Jan M
Published: October 2014

In response to a variety of stresses, mammalian cells undergo a persistent proliferative arrest known as cellular senescence. Many senescence‐inducing stressors are potentially oncogenic, strengthening the notion that senescence evolved alongside apoptosis to suppress tumorigenesis. In contrast to apoptosis, senescent cells are stably viable and have the potential to influence neighboring cells through secreted soluble factors, which are collectively known as the senescence‐associated secretory phenotype (SASP). However, theSASPhas been associated with structural and functional tissue and organ deterioration and may even have tumor‐promoting effects, raising the interesting evolutionary question of why apoptosis failed to outcompete senescence as a superior cell fate option. Here, we discuss the advantages that the senescence program may have over apoptosis as a tumor protective mechanism, as well as non‐neoplastic functions that may have contributed to its evolution. We also review emerging evidence for the idea that senescent cells are present transiently early in life and are largely beneficial for development, regeneration and homeostasis, and only in advanced age do senescent cells accumulate to an organism's detriment.
An unusual myocardial infarction
Authors: Di Michele Sara , Mirabelli Francesca , Galzerano Domenico , Mankad Sunil
Published: October 2014

We present a 74-year-old male with a chondrosarcoma, who presented with chest pain. The history, electrocardiogram (ECG), and biomarkers established the diagnosis of myocardial infarction (MI); angiography did not show coronary atherosclerosis and, both initial transthoracic echocardiogram and chest computed tomography (CT), did not demonstrate any cardiac abnormalities. A second echocardiogram following a routine ECG showed presence of a mass involving the right ventricle and the cardiac apex that was confirmed by chest CT scan. We underline the importance of considering cardiac tumors in the clinical arena of MI management.

Learning points

Cardiac tumors cause ECG changes similar to ischemic heart diseases.

Keep in mind cardiac tumors when performing transthoracic echocardiogram (TTE) in the setting of suspected MI.

TTE is the technique of choice in detecting cardiac tumors.
Aberrant miR199a-5p/caveolin1/PPARα axis in hepatic steatosis
Authors: Li Bo , Zhang Zhiguo , Zhang Huizhi , Quan Kai , Lu Yan , Cai Dongsheng , Ning Guang
Published: October 2014

The prevalence of non-alcoholic fatty liver disease (NAFLD), a condition characterized by an excessive accumulation of triglycerides (TGs) in hepatocytes, has dramatically increased globally during recent decades. MicroRNAs (miRs) have been suggested to play crucial roles in many complex diseases and lipid metabolism. Our results indicated that miR199a-5p was remarkably upregulated in free fatty acid (FA)-treated hepatocytes. To investigate the role of miR199a-5p in the pathogenesis of fatty liver and the potential mechanism by which miR199a-5p regulates NAFLD, we first transfected two hepatocyte cell lines, HepG2 and AML12 cells, with agomiR199a-5p or antagomiR199a-5p. Our results indicated that miR199a-5p overexpression exacerbated deposition of FA and inhibited ATP levels and mitochondrial DNA (mtDNA) contents. Consistently, suppression of miR199a-5p partially alleviated deposition of FA and increased ATP levels and mtDNA contents. Moreover, miR199a-5p suppressed the expression of mitochondrial FA β-oxidation-related genes through inhibition of caveolin1 (CAV1) and the related peroxisome proliferator-activated receptor alpha (PPARα) pathway. Furthermore, suppression ofCAV1gene expression byCAV1siRNA inhibited the PPARα signalling pathway. Finally, we examined the expression of miR199a-5p in liver samples derived from mice fed a high-fat diet,db/dbmice,ob/obmice and NAFLD patients, and found that miR199a-5p was upregulated whileCAV1andPPARAwere downregulated in these systems, which was strongly indicative of the essential role of miR199a-5p in NAFLD. In summary, miR199a-5p plays a vital role in lipid metabolism, mitochondrial activity and mitochondrial β-oxidation in liver. Upregulated miR199a-5p in hepatocytes may contribute to impaired FA β-oxidation in mitochondria and aberrant lipid deposits, probably via CAV1 and the PPARα pathway.
Too Much Success for Recent Groundbreaking Epigenetic Experiments
Authors: Francis Gregory
Published: October 2014

An article reporting statistical evidence for epigenetic transfer of learned behavior has important implications, if true. With random sampling, real effects do not always result in rejection of the null hypothesis, but the reported experiments were uniformly successful. Such an outcome is expected to occur with a probability of 0.004.
Yeast Systems Biology: Our Best Shot at Modeling a Cell
Authors: Boone Charles
Published: October 2014

THE Genetics Society of America’s Edward Novitski Prize recognizes an extraordinary level of creativity and intellectual ingenuity in the solution of significant problems in genetics research. The 2014 recipient, Charles Boone, has risen to the top of the emergent discipline of postgenome systems biology by focusing on the global mapping of genetic interaction networks. Boone invented the synthetic genetic array (SGA) technology, which provides an automated method to cross thousands of strains carrying precise mutations and map large-scale yeast genetic interactions. These network maps offer researchers a functional wiring diagram of the cell, which clusters genes into specific pathways and reveals functional connections.
It’s Not About You: A Simple Proposition for Improving Biology Education
Authors: Wright Robin
Published: October 2014

THE Genetics Society of America’s Elizabeth W. Jones Award for Excellence in Education recognizes significant and sustained impact on genetics education. Consistent with her philosophy of linking research and education, the 2014 Awardee Robin Wright includes undergraduate students in all of her research. She seeks to teach how to think like and to actually be a biologist, working in teams and looking at real-world problems. She emphasizes a learner-centered model of classroom work that promotes and enhances lifelong skills, and has transformed biology education at the University of Minnesota through several efforts including developing the interactive, stimulating Foundations of Biology course sequence, encouraging active learning and open-ended research; supporting the construction of Active Learning Classrooms; and establishing Student Learning Outcomes, standards that measure biology education. She serves as founding editor-in-chief of CourseSource, focusing national effort to collect learner-centered, outcomes-based teaching resources in undergraduate biology.
Biased Estimates of Diminishing-Returns Epistasis? Empirical Evidence Revisited
Authors: Berger David , Postma Erik
Published: October 2014

Empirical evidence for diminishing fitness returns of beneficial mutations supports Fisher’s geometric model. We show that a similar pattern emerges through the phenomenon of regression to the mean and that few studies correct for it. Although biases are often small, regression to the mean has overemphasized diminishing returns and will hamper cross-study comparisons unless corrected for.
Cavitation erosion resistance of sewer pipe materials
Authors: Fairfield Charles A.
Published: October 2014

A cavitating high-pressure water-jet provided the means by which a range of materials (plastics, clay and concrete) were eroded. The measured erosion resistance was a proxy for an initially unknown combination of other properties: strength, fracture toughness, impact resistance, hardness, surface roughness, and limiting service temperature. To ascertain the cause of damage to sewers during high-pressure water-jetting, information about which material properties contributed to the measured erosion resistance under a standard high-pressure water-jetting test were found. The experimental work, and published literature, provided a database of physico-mechanical, physico-chemical, thermal and tribological material properties each of which in turn were correlated with the measured jetting resistance. The properties best correlated with the jetting resistance were: maximum service temperature (R2  =  0ṡ93), elastic modulus (R2  =  0ṡ90), surface roughness (R2  =  0ṡ89), density (R2  =  0ṡ87), and thermal conductivity (R2  =  0ṡ87). The correlation coefficient between jetting resistance and impact resistance (R2  =  0ṡ56) lay just outside the top 10, suggesting that this was not an impact problem but a more complex combination of strength, roughness, and heat dissipation despite actual failures ultimately resulting from fracture (for which toughness was nevertheless also poorly correlated (R2  =  −0ṡ38)). Traditional mechanical wear, abrasion, and erosion resistance parameters (Taber abrasion (R2  =  −0ṡ24), limiting pressure-velocity (R2  =  −0ṡ57), and wear index (R2  =  −0ṡ23)) failed to correlate with the jetting resistance.
Landscape‐scale pest suppression is mediated by timing of predator arrival
Authors: Costamagna Alejandro C. , Venables William N. , Schellhorn Nancy A.
Published: October 2014

There is increasing evidence that biological control of agricultural pests is affected by the landscape context, although the mechanisms behind this pattern have received little attention. Ecological theory predicts that one key mechanism mediating successful pest suppression is early predator immigration to agricultural fields. However, the importance of this population process under different landscape contexts remains unknown. Here, we elucidate the relative importance of landscape context and timing of predator immigration on aphid suppression by manipulating exposure to predation in agroecosystems located across a gradient of landscape complexity in a subtropical horticultural region in Australia. Aphid suppression varied with landscape context, from populations escaping control to almost complete pest suppression. In general, we found higher aphid suppression when predators were allowed immediate and continuous access to aphids than when predators were delayed or excluded for a week, but responses varied in each landscape. Contrary to previous reports from temperate agricultural landscapes, aphid suppression was neutral or negatively associated with natural and seminatural vegetation, whereas aphid suppression was positively associated with landscapes with a higher proportion of alfalfa. When landscapes were classified according to their levels of complexity, we showed that early predation resulted in similar levels of pest suppression in simplified landscapes (i.e., with low proportions of alfalfa and habitat diversity) as late predation in complex landscapes (i.e., with high proportions of alfalfa and habitat diversity). Our data show that timing of predator arrival to agricultural fields is as important as landscape complexity for mediating pest control in agroecosystems. Furthermore, our results suggest that key distributions of suitable habitats that facilitate natural enemy movement can enhance biological control in simplified landscapes.
Healthy Birth Practice #5: Avoid Giving Birth on Your Back and Follow Your Body’s Urge to Push
Authors: DiFranco Joyce T. , Curl Marilyn
Published: October 2014

Women in the United States are still giving birth in the supine position and are restricted in how long they can push and encouraged to push forcefully by their caregivers. Research does not support these activities. There is discussion about current research and suggestions on how to improve the quality of the birth experience. This article is an updated evidence-based review of the “Lamaze International Care Practices That Promote Normal Birth, Care Practice #5: Spontaneous Pushing in Upright or Gravity-Neutral Positions,” published in The Journal of Perinatal Education, 16(3), 2007.
ICT Use and Achievement in Three European Countries: What Does PISA Tell Us?
Authors: Steffens Karl
Published: October 2014

During the last decade, in many European countries large investments were made to foster the use of information and communication technology (ICT) in education with the expectation that ICT would make teaching and learning more effective. This would, for example, become evident in scores obtained by students in the Programme for International Student Assessment (PISA). PISA studies show, however, that PISA achievements do not increase with ICT use. The question for research is why high-frequency ICT use tends to be related to lower PISA achievements. To answer this question, the author has looked at PISA results published by the Organisation for Economic Cooperation and Development (OECD) as well as at the results of his own analyses of PISA data. While it seems that ICT use as well as PISA achievements are related to cultural capital, the findings are not clear-cut and vary among the three European countries chosen for investigation.
Cross-Cultural Approaches to Biographical Interviews: Looking at Career Transitions and Lifelong Learning
Authors: Barabasch Antje , Merrill Barbara
Published: October 2014

This article focuses on the methodological approaches used in the European Centre for the Development of Vocational Training (Cedefop) research project ‘Learning for Career and Labour Market Transitions – individual biographies’. In particular, it illuminates how biographical approaches were employed to help the in-depth understanding of career transitions and work identities as biographical narratives highlight the complex processes of learning, labour market experiences and working-life transitions. Within Europe, biographical approaches in terms of interviewing and analysis are used differently as a result of historical, intellectual and cultural traditions, and this was the case in this study. However, although different approaches were utilised, the stories generated rich data which enabled comparisons to take place across the five countries.
Narratives about Labour Market Transitions
Authors: Cort Pia , Thomsen Rie
Published: October 2014

In European Union policy, Denmark is often referred to as a model country in terms of its flexicurity model and provision of financial support and access to education and training during periods of unemployment, i.e. during transitional phases in a working life. However, in the research on flexicurity and its implications for labour market transitions, little attention has been paid to the views and experiences of the individuals concerned. The aim of this article is to connect the grand narrative with individual narratives about labour market transitions in the Danish flexicurity system. On the basis of narrative interviews with skilled workers, this article explores how labour market transitions are experienced by the individual and the role played by national support structures in the individual narratives. The article shows how, for the individual, a transition may prove to be a valuable learning experience during which radical career decisions are taken, and how support structures may work to the detriment of such learning and of the principles behind flexicurity. The article points to a reconceptualisation of transitions as important learning opportunities during which (more) adequate support structures could be provided.
Learning about the Importance of Education for Labour Market Transitions
Authors: Oliver Esther , Tellado Itxaso , De Botton Lena
Published: October 2014

This article centres on the importance given by individuals to the process of education in labour market transitions and how they manage to overcome obstacles to achieve their goals. Many of the stories in the Spanish research were transformative and innovative despite the context of high levels of unemployment in Spain due to the global economic crisis. In this article the educational context is explained together with the educational paths available to go to university, to vocational education and training, or towards abandonment. Qualitative data analysis has been conducted to analyse the narrative interviews. The stories highlight the transformative results of those who participate in formal education, and that learning from experience and cultural intelligence are used as strategies to follow for overcoming the challenges of labour market transitions.
The Impact of Learning on Women's Labour Market Transitions
Authors: Haasler Simone R.
Published: October 2014

Women play an increasingly important role in the labour market and as wage earners. Moreover, in many countries, young women have outperformed men in terms of educational attainment and qualification. Still, women's human capital investment does not pay off as it does for men as they are still significantly disadvantaged on the labour market. Based on a qualitative empirical investigation with women in their mid-career, this article investigates the role of learning for women's labour market participation and career paths. Women's careers complexly intersect with role expectations, family needs, the career of the partner and anticipation of low returns of educational investment. This is typically reflected in discontinuous employment, part-time work and women's secondary wage earner position in the family. Furthermore, women qualified at the intermediate skills level are more likely to move horizontally in their career than vertically. Horizontal mobility thereby requires significant engagement with learning as the German labour market usually requires a formal qualification to realise a career change. Learning and further training thus become instrumental to facilitate and support women's career transitions, which are often aimed at re-entering regular employment after longer periods of family-related interruptions and/or to remain qualified in jobs in the social, health and educational fields, all of which are female dominated. Ultimately, women's significant engagement with continuing learning is not primarily expected to support career advancement and vertical mobility, particularly as it can neither alter discontinuities of employment nor the German-specific nexus between welfare, family and education policies and the labour market. This challenges the lifelong learning rhetoric insofar as one key aim of lifelong learning policies is to support labour market inclusion and the mobility of disadvantaged groups.
Ligand-Activated PPARα-Dependent DNA Demethylation Regulates the Fatty Acid β-Oxidation Genes in the Postnatal Liver
Authors: Ehara Tatsuya , Kamei Yasutomi , Yuan Xunmei , Takahashi Mayumi , Kanai Sayaka , Tamura Erina , Tsujimoto Kazutaka , Tamiya Takashi , Nakagawa Yoshimi , Shimano Hitoshi , Takai-Igarashi Takako , Hatada Izuho , Suganami Takayoshi , Hashimoto Koshi , Ogawa Yoshihiro
Published: October 2014

The metabolic function of the liver changes sequentially during early life in mammals to adapt to the marked changes in nutritional environment. Accordingly, hepatic fatty acid β-oxidation is activated after birth to produce energy from breast milk lipids. However, how it is induced during the neonatal period is poorly understood. Here we show DNA demethylation and increased mRNA expression of the fatty acid β-oxidation genes in the postnatal mouse liver. The DNA demethylation does not occur in the fetal mouse liver under the physiologic condition, suggesting that it is specific to the neonatal period. Analysis of mice deficient in the nuclear receptor peroxisome proliferator–activated receptor α (PPARα) and maternal administration of a PPARα ligand during the gestation and lactation periods reveal that the DNA demethylation is PPARα dependent. We also find that DNA methylation of the fatty acid β-oxidation genes are reduced in the adult human liver relative to the fetal liver. This study represents the first demonstration that the ligand-activated PPARα-dependent DNA demethylation regulates the hepatic fatty acid β-oxidation genes during the neonatal period, thereby highlighting the role of a lipid-sensing nuclear receptor in the gene- and life-stage–specific DNA demethylation of a particular metabolic pathway.
Arterial blood pressure as a predictor of the response to fluid administration in euvolemic nonhypotensive or hypotensive isoflurane-anesthetized dogs
Authors: Muir William W. , Ueyama Yukie , Pedraza-Toscano Adriana , Vargas-Pinto Pedro , Delrio Carlos L. , George Robert S. , Youngblood Bradley L. , Hamlin Robert L.
Published: October 2014

Objective—To determine the effects of rapid small-volume fluid administration on arterial blood pressure measurements and associated hemodynamic variables in isoflurane-anesthetized euvolemic dogs with or without experimentally induced hypotension.

Design—Prospective, randomized, controlled study.

Animals—13 healthy dogs.

Procedures—Isoflurane-anesthetized dogs were randomly assigned to conditions of nonhypotension or hypotension (mean arterial blood pressure, 45 to 50 mm Hg) and treatment with lactated Ringer's solution (LRS) or hetastarch (3 or 10 mL/kg [1.4 or 4.5 mL/lb] dose in a 5-minute period or 3 mL/kg dose in a 1-minute period [4 or 5 dogs/treatment; ≥ 10-day interval between treatments]). Hemodynamic variables were recorded before and for up to 45 minutes after fluid administration.

Results—IV administration of 10 mL/kg doses of LRS or hetastarch in a 5-minute period increased right atrial and pulmonary arterial pressures and cardiac output (CO) when dogs were nonhypotensive or hypotensive, compared with findings before fluid administration; durations of these effects were greater after hetastarch administration. Intravenous administration of 3 mL of hetastarch/kg in a 5-minute period resulted in an increase in CO when dogs were nonhypotensive. Intravenous administration of 3 mL/kg doses of LRS or hetastarch in a 1-minute period increased right atrial pressure and CO when dogs were nonhypotensive or hypotensive.

Conclusions and Clinical Relevance—Administration of LRS or hetastarch (3 or 10 mL/kg dose in a 5-minute period or 3 mL/kg dose in a 1-minute period) improved CO in isoflurane-anesthetized euvolemic dogs with or without hypotension. Overall, arterial blood pressure measurements were a poor predictor of the hemodynamic response to fluid administration.
Empirical Observations of Congestion Propagation and Dynamic Partitioning with Probe Data for Large-Scale Systems
Authors: Ji Yuxuan , Luo Jun , Geroliminis Nikolas
Published: October 2014

Research on congestion propagation in large urban networks has been based mainly on microsimulations of link-level traffic dynamics. However, both the unpredictability of travel behavior and the complexity of accurate physical modeling present challenges, and simulation results may be time-consuming and unrealistic. This paper explores empirical data from large-scale urban networks to identify hidden information in the process of congestion formation. Specifically, the spatiotemporal relation of congested links is studied, congestion propagation is observed from a macroscopic perspective, and critical congestion regimes are identified to aid in the design of peripheral control strategies. To achieve these goals, the maximum connected component of congested links is used to capture congestion propagation in the city. A data set of 20,000 taxis with global positioning system (GPS) data from Shenzhen, China, is used. Empirical macroscopic fundamental diagrams of congested regions observed during propagation are presented, and the critical congestion regimes are quantified. The findings show that the proposed methodology can effectively distinguish congestion pockets from the rest of the network and efficiently track congestion evolution in linear time 0(n).
Dynamics of Urban Network Traffic flow during a Large-Scale Evacuation
Authors: Zockaie Ali , Mahmassani Hani S. , Saberi Meead , Verbas Ömer
Published: October 2014

This paper explores some of the dynamics of urban network traffic flow during a large-scale evacuation in the context of the network fundamental diagram (NFD). The structure of the evacuation demand can significantly affect network performance. A radial-shaped structure results in a more stable network recovery compared with a directional evacuation structure. This study confirms the existence of unloading–reloading hysteresis when a network is subject to successive cycles of loading and unloading. If a network undergoes a complete or near-complete recovery, the reloading path in the NFD follows almost the same path as in the initial loading. Results suggest that the linear relationship between average network flow and trip completion rate does not always hold, as previously thought. The relationship becomes highly scattered and nonlinear when the network is highly congested and under disruption and the number of adaptive drivers is sufficiently large. Frequent route switching by adaptive drivers can artificially increase the average network flow but does not necessarily increase the network output (trip completion rate). Adaptive driving increases fluctuations in the NFD; however, it reduces hysteresis and gridlock while increasing network capacity.
On the Consistency of Freeway Macroscopic Merging Models
Authors: Tomé Josep M. , Soriguera Francesc , Geroliminis Nikolas
Published: October 2014

Many first-order macroscopic models for freeway traffic have been developed since the seminal work on the well-known Lighthill–Whitham–Richards, or LWR, continuous model. The asymmetric cell transmission model (ACTM) is a widely accepted macroscopic model integrated into a variety of freeway traffic control frameworks. The model is based on the original cell transmission model; modified merge equations make it computationally tractable for optimization of ramp metering. However, when the common simplistic calibration of the model is used, an infeasible merging behavior is observed at uncontrolled merges, and the resulting queue lengths are not accurately estimated. This paper proposes an elegant analytical relationship, based on traffic flow theory, for calibrating the two parameters involved in the ACTM merge model. The method ensures the physical consistency of the dynamics involved in queue processes in the proximity of a noncontrolled merge junction. This method should be an essential feature of any freeway traffic model.
Clustering Approach for Assessing the Travel Time Variability of Arterials
Authors: Hans Etienne , Chiabaut Nicolas , Leclercq Ludovic
Published: October 2014

Travel time variability may significantly influence a driver's route choice. Urban infrastructure managers are interested in reliable estimation of travel time, which could provide better information to drivers, encourage reassignment on the network, and optimize use of the network. This study addresses arterials in undersaturated conditions with known fixed-time traffic signals. The kinematic wave model was chosen to represent traffic dynamics simply. A semianalytical (grid-free) method is applied to determine the separation between vehicle groups at each signal of the arterial. The main contribution of this paper is an aggregated diagram that describes the functioning of this arterial. The aggregated diagram graphically provides a direct assessment of vehicle travel times with respect to their departure and traffic flow. This tool depends only on signal settings and is cyclic and invariant for fixed-time signals. The diagram can be used to generate probabilistic travel time distributions when some input parameters are uncertain. The diagram appears to offer insight when traffic flow is not accurately known.
Modeling Reliability in Freeway Networks
Authors: Wu Ning , Geistefeldt Justin
Published: October 2014

The stochastic nature of freeway capacity typically has been analyzed at specific points that are considered bottlenecks. The stochastic relationship between the adjacent bottlenecks has not been taken into account. This paper introduces a concept for the stochastic interpretation of capacity and breakdown probability within a larger freeway network consisting of several combined bottlenecks. The presented stochastic methodology delivers a theoretical average capacity and the probability of breakdown for freeway segments of different lengths. The methodology can also be used to identify the effects of consecutive freeway segments and bottlenecks such as on-ramps, off-ramps, and weaving areas having different characteristics. The proposed method makes it possible to determine the breakdown probability as a function of the average volume or density. Hence, the risk of traffic flow disturbance along a freeway segment or within a freeway network can be analyzed.
Shock Wave Approach for Estimating Queue Length at Signalized Intersections by Fusing Data from Point and Mobile Sensors
Authors: Cai Qing , Wang Zhongyu , Zheng Lingyu , Wu Bing , Wang Yinhai
Published: October 2014

With the growth in traffic sensing data, the measurement of levels of service such as queue length at intersections in real time has been receiving considerable attention. This paper examines how to estimate real-time cycle-by-cycle queue length at signalized intersections by using the data of an upstream point sensor and the traveling trajectory of a probe vehicle observed by a mobile sensor. Three cases are based on the space relationships between the rear of a queue, the point sensor location, and the vehicle stop or start-up point. When the data of point sensors and mobile sensors are fused, critical break points can be identified to indicate several key states of the queue formation and dissipation. Estimation models of the maximum queue length, based on the Lighthill–Whitham–Richards theory, are proposed for the three cases. The presented algorithm does not impose any restrictions on the traffic condition (i.e., oversaturated and undersaturated conditions). The methodology is applied to ground truth data observed from the field in Shanghai, China. The mean average percentage errors of the first two cases are 11.60% and 9.98%, which means the models for the cases have reasonable estimating accuracy. The mean average percentage error of the model for the third case is 26.40%, indicating that the performance degrades but still has acceptable accuracy. Limitations on application of the proposed models and directions for future research are discussed.
Comprehensive Approach for the Sensitivity Analysis of High-Dimensional and Computationally Expensive Traffic Simulation Models
Authors: Ge Qiao , Ciuffo Biagio , Menendez Monica
Published: October 2014

The reliability of traffic model results is strictly connected to the quality of its calibration. A challenge arising in this context concerns the selection of the most influential input parameters. A model sensitivity analysis should be used with this aim. However, because of the limitations of time and computational resources, a proper sensitivity analysis is rarely performed in common practice. A recent study introduced a methodology based on Gaussian process metamodels for the sensitivity analysis of computationally expensive traffic simulation models. The main limitation was a dependence on model dimensionality. When the model has more than about 15 to 20 parameters, estimation of a Gaussian process metamodel (also known as a Kriging metamodel) may become problematic. In this paper, the Kriging-based approach is coupled with a recently developed approach, quasi-optimized trajectory-based elementary effects (quasi-OTEE), for the sensitivity analysis of computationally expensive models. The quasi-OTEE sensitivity analysis can be used to identify the whole subset of sensitive parameters of a high-dimensional model, and the Kriging-based sensitivity analysis can then be used to refine the analysis and to rank the different parameters of the subset in a more reliable way. Application of this new sequential sensitivity analysis method is illustrated with the Wiedemann-74 car-following model. Results show that the new method requires 40 times fewer model evaluations than a standard variance-based sensitivity analysis to identify the influential parameters and their ranks.
Calibration, Estimation, and Sampling Issues of Car-Following Parameters
Authors: Monteil Julien , Billot Romain , Sau Jacques , Buisson Christine , Faouzi Nour-Eddin El
Published: October 2014

Drivers behave in different ways, and these different behaviors are a cause of traffic disturbances. A key objective for simulation tools is to correctly reproduce this variability, in particular for car-following models. From data collection to the sampling of realistic behaviors, a chain of key issues must be addressed. This paper discusses data filtering, robustness of calibration, correlation between parameters, and sampling techniques of acceleration-time continuous car-following models. The robustness of calibration is systematically investigated with an objective function that allows confidence regions around the minimum to be obtained. Then, the correlation between sets of calibrated parameters and the validity of the joint distributions sampling techniques are discussed. This paper confirms the need for adapted calibration and sampling techniques to obtain realistic sets of car-following parameters, which can be used later for simulation purposes.
Empirical Analysis of Vehicle Time Headways and Speeds on Rural Two-Lane, Two-Way Roads
Authors: Rossi Riccardo , Gastaldi Massimiliano , Pascucci Federico
Published: October 2014

Accurate knowledge of vehicle time headway (TH) and speed distributions is essential in many traffic engineering applications, such as capacity and level-of-service analysis, and in several contexts (operations at road segments, priority junctions, roundabouts, merging maneuvers). Other fields of interest are represented by vehicle generation in traffic microsimulation models and driving simulation applications. This paper presents results from an experimental analysis of vehicle TH and speed distributions on two-lane, two-way roads. The focus is on rural roads in Northern Italy, which are characterized by various levels of traffic and where data were collected by radar sensors. A trendless analysis of observed THs was carried out. Analysis then focused on estimating a well-known TH model, gamma-generalized queuing. Statistical analysis of the available data allowed testing of a set of speed distribution models, highlighting their goodness of fit with reference to empirical distributions. Completing the analysis, bivariate distributions were estimated to represent headway and speed distributions. The traffic parameters considered to affect TH distributions were flow rate and flow composition (percentage of heavy vehicles). Exogenous conditions, such as weather and road geometric futures, were common to all analyzed time periods and cross sections. The final goal of the analysis was to create a picture of the relationship between traffic conditions and speed and headway distributions for a typical road.
Improving Intersection Behavior through Delay-Based Left-Turn Phase Initiation
Authors: Lavrenz Steven M. , Hainen Alexander M. , Stevens Amanda L. , Day Christopher M. , Li Howell , Freije Richard S. , Smith W. Benjamin , Summers Hayley , Sturdevant James R. , Bullock Darcy M.
Published: October 2014

Serving protected left-turn phases for one or two vehicles can often be an inefficient use of cycle green time when the opposing through movements are over capacity. This paper assesses the performance of an intersection at which controller logic is applied to delay the call for a protected left-turn phase on the basis of vehicle wait times. During four weeks of evaluation, the delay on left-turn phase calls was varied in 25-s increments from 0 to 75 s. The results indicate that delaying left-turn phase initiation substantially increases the amount of green time for saturated through movements while minimally increasing the travel delay for left-turning drivers. The recommendation is made for agencies to consider using a delay in the range of 25 to 50 s for calling protected phases at intersections at which the opposing through movement is oversaturated and could benefit from additional green time. This paper presents one of the first quantitative studies evaluating potential intersection capacity and performance improvements with respect to left-turn detector delay.
Optimal Intersection Operation with Median U-Turn
Authors: Zhao Jing , Ma Wanjing , Head K. Larry , Yang Xiaoguang
Published: October 2014

The median U-turn intersection is a potential method for relieving traffic congestion at intersections. Median U-turn intersections can be classified into six types, according to the prohibited traffic movements. Although much is known about the technology of the median U-turn, efforts have focused on its geometric design, safety analysis, and evaluation. In this paper, a lane-based optimization model is proposed for the integrated design of median U-turn intersection types, lane markings, distances between the median crossovers and the main intersection, and signal timings. The capacity maximization problem is considered, and a set of constraints is determined that ensures the feasibility and safety of the optimization results. The optimization is formulated as a multi-objective mixed-integer nonlinear programming problem. It is solved by transformation to a series of mixed-integer linear programming models. The latter can be solved by the standard branch-and-bound technique. Extensive numerical analysis and a case study have shown the effectiveness of the proposed method. In addition, the method can assist transportation professionals in the proper selection of U-turn types and in the design of intersections with median U-turns.
MET and Small-Cell Lung Cancer
Authors: Gelsomino Francesco , Rossi Giulio , Tiseo Marcello
Published: October 2014

Small-cell lung cancer (SCLC) is one of the most aggressive lung tumors. The majority of patients with SCLC are diagnosed at an advanced stage. This tumor type is highly sensitive to chemo-radiation treatment, with very high response rates, but invariably relapses. At this time, treatment options are still limited and the prognosis of these patients is poor. A better knowledge of the molecular biology of SCLC allowed us to identify potential druggable targets. Among these, the MET/HGF axis seems to be one of the most aberrant signaling pathways involved in SCLC invasiveness and progression. In this review, we describe briefly all recent literature on the different molecular profiling in SCLC; in particular, we discuss the specific alterations involving c-MET gene and their implications as a potential target in SCLC.
MicroRNAs Regulate Vascular Medial Calcification
Authors: Leopold Jane
Published: October 2014

Vascular calcification is highly prevalent in patients with coronary artery disease and, when present, is associated with major adverse cardiovascular events, including an increased risk of cardiovascular mortality. The pathogenesis of vascular calcification is complex and is now recognized to recapitulate skeletal bone formation. Vascular smooth muscle cells (SMC) play an integral role in this process by undergoing transdifferentiation to osteoblast-like cells, elaborating calcifying matrix vesicles and secreting factors that diminish the activity of osteoclast-like cells with mineral resorbing capacity. Recent advances have identified microRNAs (miRs) as key regulators of this process by directing the complex genetic reprogramming of SMCs and the functional responses of other relevant cell types relevant for vascular calcification. This review will detail SMC and bone biology as it relates to vascular calcification and relate what is known to date regarding the regulatory role of miRs in SMC-mediated vascular calcification.
Redundancy of Exchangeable Estimators
Authors: Santhanam Narayana , Sarwate Anand , Woo Jae
Published: October 2014

Exchangeable random partition processes are the basis for Bayesian approaches to statistical inference in large alphabet settings. On the other hand, the notion of the pattern of a sequence provides an information-theoretic framework for data compression in large alphabet scenarios. Because data compression and parameter estimation are intimately related, we study the redundancy of Bayes estimators coming from Poisson–Dirichlet priors (or “Chinese restaurant processes”) and the Pitman–Yor prior. This provides an understanding of these estimators in the setting of unknown discrete alphabets from the perspective of universal compression. In particular, we identify relations between alphabet sizes and sample sizes where the redundancy is small, thereby characterizing useful regimes for these estimators.
Combining Satellite Data and Community-Based Observations for Forest Monitoring
Authors: Pratihast Arun , DeVries Ben , Avitabile Valerio , De Bruin Sytze , Kooistra Lammert , Tekle Mesfin , Herold Martin
Published: October 2014

Within the Reducing Emissions from Deforestation and Degradation (REDD+) framework, the involvement of local communities in national forest monitoring activities has the potential to enhance monitoring efficiency at lower costs while simultaneously promoting transparency and better forest management. We assessed the consistency of forest monitoring data (mostly activity data related to forest change) collected by local experts in the UNESCO Kafa Biosphere Reserve, Ethiopia. Professional ground measurements and high resolution satellite images were used as validation data to assess over 700 forest change observations collected by the local experts. Furthermore, we examined the complementary use of local datasets and remote sensing by assessing spatial, temporal and thematic data quality factors. Based on this complementarity, we propose a framework to integrate local expert monitoring data with satellite-based monitoring data into a National Forest Monitoring System (NFMS) in support of REDD+ Measuring, Reporting and Verifying (MRV) and near real-time forest change monitoring.
Creating an eLearning Resource to Improve Knowledge and Understanding of Pregnancy in the Context of HIV Infection
Authors: Kelly Carmel , Reid Esther , Lohan Maria , Alderdice Fiona , Spence Dale
Published: October 2014

Patient narratives have much to teach healthcare professionals about the experience of living with a chronic condition. While the biomedical narrative of HIV treatment is hugely encouraging, the narrative of living with HIV continues to be overshadowed by a persuasive perception of stigma. This paper presents how we sought to translate the evidence from a qualitative study of the perspectives of HIV affected pregnant women and expectant fathers on the care they received, from the pre conception to post natal period, into educational material for maternity care practice. Narrative scripts were written based on the original research interviews, with care taken to reflect the key themes from the research. We explore the way in which the qualitative findings bring to life patient and partner experiences and what it means for nurses, midwives and doctors to be prepared to care for couples affected by HIV. In so doing, we challenge the inequity between the dominance of biomedical knowledge over understanding the patient experience in the preparation of health professionals to care for HIV affected women and men who are having a baby or seeking to have a baby.
Characterization of Paraquat-Induced miRNA Profiling Response in hNPCs Undergoing Proliferation
Authors: Huang Min , Lou Dan , Cai Qian , Chang Xiuli , Wang Xinjin , Zhou Zhijun
Published: October 2014

Aberration during the development of the central nervous system (CNS) due to environmental factors underlies a variety of adverse developmental outcomes. Paraquat (PQ) is a widely studied neurotoxicant that perturbs the normal structure/function of adult CNS. Yet, the impacts of PQ exposure on the developing CNS remain unclear. miRNAs represent a class of small non-coding RNA molecules involved in the regulation of neural development. Thus in the present study, we analyzed the impacts of PQ on the miRNome of human neural progenitor cells (hNPCs) during proliferation by using the Exiqon miRCURY™ LNA Array. A total of 66 miRNAs were identified as differentially expressed in proliferating hNPCs upon PQ treatment. miRTarBase prediction identified 1465 mRNAs, including several genes (e.g., nestin, sox1, ngn1) previously proved to be associated with the neural proliferation and differentiation, as target genes of PQ-induced differentially expressed miRNAs. The database for annotation, visualization and integrated discovery (DAVID) bioinformatics analysis showed that target genes were enriched in regulation of cell proliferation and differentiation, cell cycle and apoptosis as well as tumor protein 53 (p53), Wnt, Notch and mitogen-activated protein kinases (MAPK) signaling pathways (p < 0.001). These findings were confirmed by real-time RT-PCR. Based on our results we conclude that PQ-induced impacts on the miRNA profiling of hNPCs undergoing proliferation may underlie the developmental neurotoxicity of PQ.
Transcriptional Regulation of Programmed Hypertension by Melatonin: An Epigenetic Perspective
Authors: Tain You-Lin , Huang Li-Tung , Chan Julie
Published: October 2014

Melatonin is an endogenously produced indoleamine and secreted by the pineal gland. Melatonin has pleiotropic bioactivities and is involved in epigenetic regulation. Suboptimal conditions during maternal and perinatal phases can elicit epigenetic regulation of genes for nephrogenesis and reset physiological responses to develop programmed hypertension. This review discusses the early utility of melatonin to prevent programmed hypertension in later life by epigenetic regulation in the kidney, with an emphasis on: (1) the role of melatonin in epigenetic regulation; (2) the beneficial effects of melatonin on programmed hypertension; (3) epigenetic regulation of maternal melatonin therapy in different developmental windows of offspring kidneys analyzed by whole-genome RNA next-generation sequencing; and (4) current blocks in the application of melatonin in preventing programmed hypertension.
Nanoparticle Encapsidation of Flock House Virus by Auto Assembly of Tobacco Mosaic Virus Coat Protein
Authors: Maharaj Payal , Mallajosyula Jyothi , Lee Gloria , Thi Phillip , Zhou Yiyang , Kearney Christopher , McCormick Alison
Published: October 2014

Tobacco Mosaic virus (TMV) coat protein is well known for its ability to self-assemble into supramolecular nanoparticles, either as protein discs or as rods originating from the ~300 bp genomic RNA origin-of-assembly (OA). We have utilized TMV self-assembly characteristics to create a novel Flock House virus (FHV) RNA nanoparticle. FHV encodes a viral polymerase supporting autonomous replication of the FHV genome, which makes it an attractive candidate for viral transgene expression studies and targeted RNA delivery into host cells. However, FHV viral genome size is strictly limited by native FHV capsid. To determine if this packaging restriction could be eliminated, FHV was adapted to express enhanced green fluorescent protein (GFP), to allow for monitoring of functional FHV RNA activity. Then TMV OA was introduced in six 3' insertion sites, with only site one supporting functional FHV GFP expression. To create nanoparticles, FHV GFP-OA modified genomic RNA was mixed in vitro with TMV coat protein and monitored for encapsidation by agarose electrophoresis and electron microscopy. The production of TMV-like rod shaped nanoparticles indicated that modified FHV RNA can be encapsidated by purified TMV coat protein by self-assembly. This is the first demonstration of replication-independent packaging of the FHV genome by protein self-assembly.