bluuebunny/crossref_metadata_2025 huggingface dataset:
Closing the Loop: Improving Transit through Crowdsourced Information
Authors: Barbeau Sean J.
Published: August 2018

Offering real-time arrival information to riders via mobile applications has been shown to improve the rider’s perception of transit, and even increase ridership. This direct connection to riders also offers the transit agency an opportunity to collect feedback on how transit service and infrastructure can be improved, including pedestrian and bike access to transit. These improvements will lead to an enhanced customer experience and can potentially help address Title VI access equity concerns. However, managing the sheer volume of this rider feedback can be very challenging, especially when various departments and agencies (e.g., city/county government) are involved (e.g., who owns the bench by the bus stop?). This paper discusses the design and deployment of a pilot project in Tampa, Florida, which focused on the improvement of the feedback loop from riders back to transit agencies, local government, and departments of transportation. This project made enhancements to the open-source OneBusAway mobile app, originally deployed in Tampa in 2013, to include support for the Open311 standard for issue reporting. Open311 support gives agencies the option of selecting a hosted issue management solution such as SeeClickFix.com and PublicStuff.com, or the option to utilize existing open-source Open311-compliant software. Lessons learned from regional collaboration surrounding issue reporting and infrastructure improvements are discussed, as are the technical design and challenges behind implementing such a system. The results of the first 6 months of system deployment covering 677 issue reports are presented, including specific examples of cross-jurisdictional and multimodal issues reported by the public.
Impact of Major Road Supply on Individual Travel Time Expenditure: An Exploration with a 30-Year Variation of Infrastructure and Travel
Authors: Abe Ryosuke , Axhausen Kay W.
Published: August 2018

This study estimates the impact of major road supply on individual travel time expenditures (TTEs) using data that cover 30-year variations in transportation infrastructure and travel behavior. The impacts of the supply of road and rail infrastructure are estimated with a data set that combines records of large-scale household travel surveys in the Tokyo metropolitan area conducted in 1978, 1988, 1998, and 2008. Linear and Tobit models of individual TTEs are estimated by following the behavior of birth cohorts over the 30-year period. The models incorporate the changes in transportation infrastructure, measured as lane kilometers of two levels of major road stock and vehicle kilometers of urban rail service. The results show significant negative effects of lane kilometers for higher-level and lower-level major roads on the TTEs for all travel purposes and for commuting, after controlling for socioeconomic backgrounds and generations of individuals. This study discusses that, in Tokyo, the estimated effect is more likely to reflect the effect of a major road network per se on individual TTEs than the (indirect) effect of major road supply on individual TTEs working through land development activities (i.e., induced car travel demand). For example, the caveat is that actual road investment decisions still need to consider the induced component of road traffic in addition to the (direct) effect that is estimated in this study.
Models of Human Decision-Making as Tools for Estimating and Optimizing Impacts of Vehicle Automation
Authors: Markkula Gustav , Romano Richard , Madigan Ruth , Fox Charles W. , Giles Oscar T. , Merat Natasha
Published: August 2018

With the development of increasingly automated vehicles (AVs) comes the increasingly difficult challenge of comprehensively validating these for acceptable, and ideally beneficial, impacts on the transport system. There is a growing consensus that virtual testing, where simulated AVs are deployed in simulated traffic, will be key for cost-effective testing and optimization. The least mature model components in such simulations are those generating the behavior of human agents in or around the AVs. In this paper, human models and virtual testing applications are presented for two example scenarios: (i) a human pedestrian deciding whether to cross a street in front of an approaching automated vehicle, with or without external human–machine interface elements, and (ii) an AV handing over control to a human driver in a critical rear-end situation. These scenarios have received much recent research attention, yet simulation-ready human behavior models are lacking. They are discussed here in the context of existing models of perceptual decision-making, situational awareness, and traffic interactions. It is argued that the human behavior in question might be usefully conceptualized as a number of interrelated decision processes, not all of which are necessarily directly associated with externally observable behavior. The results show that models based on this type of framework can reproduce qualitative patterns of behavior reported in the literature for the two addressed scenarios, and it is demonstrated how computer simulations based on the models, once these have been properly validated, could allow prediction and optimization of AV impacts on traffic flow and traffic safety.
Bicycle Lanes and Business Success: A San Francisco Examination
Authors: Poirier Joseph A.
Published: August 2018

This paper examines the impacts of bicycle infrastructure on business performance in San Francisco, CA. The purpose of the paper is to provide better information about the potential impacts of bicycle infrastructure on different types of business, thereby improving the planning process and providing more confidence in outcomes for stakeholders. The analysis uses secondary data on business employment and sales to measure the change over time in performance of businesses abutting a bicycle lane intervention, versus the performance of nearby but non-abutting businesses. The paper finds that bicycle lane interventions in San Francisco rarely produce profoundly negative outcomes, and that they are often associated with positive business performance outcomes. It also finds that different types of businesses experience bicycle lane interventions differently, with the implication being that transportation planners need to understand and carefully account for the mix of businesses in implementation sites.
Ex-Ante and Ex-Post Evaluation of a New Transit Information App: Modeling Use Intentions and Actual Use
Authors: Velazquez Guillermo , Kaplan Sigal , Monzon Andres
Published: August 2018

This study investigates the behavioral drivers underlying the adoption of a multimodal travel information mobile app. The hypothesized framework is validated empirically through the case-study of Madrid. Madrid’s Public Transport real-time information app (“Mi Transporte”) allows users to obtain customized and automated information. A three-wave survey containing questions aligned with the Theory of Planned Behavior was conducted in 2015 and 2016 with a representative sample of transit users. Data analysis includes a factor analysis and a structural equation model to validate the hypotheses. The model assumes that the intention to use the app can be explained as a function of attitudinal factors and respondent characteristics. Results show that the app adoption is correlated with the intention of the users to adopt it and with their willingness-to-pay; the users’ intentions can be explained by various factors like user’s expectations on the app, affinity for technology (technophilia) and the previous use of other transport apps. The roles of search functionalities, side-mode information, time saving skills and the importance of the Level of Service (LOS) are also analyzed in the model. Relations between user characteristics and latent variables are subsequently explained as well as the ex-post satisfaction and change in travel patterns to measure the impact on the transport behavior of the app users. The study provides a better understanding of app adoption based on traveler characteristics, the attributes of the app and the perception of its capabilities.
A Framework for Identifying Recurring Bottlenecks in the State Planning Process in Colorado
Authors: Deselnicu Oana , Wallis Jason
Published: August 2018

Traditional methods used in transportation planning to identify bottlenecks and mobility issues, such as the Volume-to-Capacity Ratio and the Planning Time Index, have limited usefulness in identifying the exact location and extent of bottlenecks. Moreover, existing bottleneck identification tools flag all bottleneck types without distinction, despite the fact that strategies and resources used to address each type are different. This research first proposes a taxonomy of congestion to distinguish between different types of bottlenecks. It then describes a new methodology for identifying the location of recurring bottlenecks. Recurring bottleneck locations must experience a reduction in speed, an upstream accumulation of vehicles, and recurrence at the same location over three consecutive months. The methodology is currently used in long-term transportation planning and project selection in Colorado to identify and address the most severe bottleneck locations in the state.
Quantification of Loading Environment and Flexural Demand of Prestressed Concrete Crossties under Shared Corridor Operating Conditions
Authors: Quirós-Orozco Ricardo J. , Edwards J. Riley , Qian Yu , Dersch Marcus S.
Published: August 2018

Optimization of the design of railway infrastructure and its components requires a comprehensive understanding of the loading demands that are expected. Currently, many design guidelines for track components use historical wheel loads and calculate bending moments based on broad assumptions. However, tools are available to accurately quantify and characterize the variability each load has on a particular component. This is particularly important in shared use rail corridors where higher speed passenger services operate on the same infrastructure as heavy axle load (HAL) freight trains. Each traffic type generates unique demand variabilities, and these should be incorporated into a holistic approach to optimized track design. Therefore, researchers at the University of Illinois at Urbana-Champaign (UIUC) are conducting field research aimed at the characterization of field conditions on Amtrak’s Northeast Corridor through the use of wheel impact load detector (WILD) data and concrete crosstie surface strain gauges. Results from this experimentation show high variability of loads resulting from varied types of train operations and significant differences in impact load ratios. Finally, laboratory measured flexural capacity for the concrete crossties showed a conservative design with a potential margin of improvement in reduction of residual capacity (i.e., factor of safety).
Examining the Link Between Childhood Physical Abuse and Risk for Violent Victimization in Youth and Young Adulthood in China
Authors: Khade Natasha B. , Wang Xia , Decker Scott H.
Published: August 2018

This study examines the association between childhood physical abuse and an increased risk for violent victimization in youth and young adulthood in China. It further assesses if this relationship is mediated by an individual’s routine activities. Data used in this study were collected from more than 2,000 individuals of school-based samples in Changzhi, a city of over 3 million people in Northern China. Drawing from a survey that captures childhood physical abuse, violent victimization, and routine activities, this study uses negative binominal regression to examine the relationships between childhood physical abuse, routine activities, and violent victimization among Chinese youth and young adults. We find that individuals who were physically abused in childhood were at a greater risk for violent victimization in youth and young adulthood, and that an individual’s routine activities (e.g., drinking) partially mediated this relationship. The findings from this study suggest that routine activity theory provides a useful framework for explaining the link between childhood physical abuse and risk for violent victimization in the Chinese context. Furthermore, our findings stress the importance of future research to look more closely at childhood experiences when studying future behaviors. In addition, our findings challenge beliefs held among Chinese parents about the acceptability of physical punishment to discipline children. These findings can be used to shape programs that create awareness of acceptable parenting practices in China.
A Nation-Wide Assessment of Empowerment Among States’ Personal Protective Order Statutes
Authors: Richards Tara N. , Gover Angela R. , Tudor Alison
Published: August 2018

The Personal Protective Order (PPO) and the PPO process may provide an opportunity to shift power dynamics from the state/abuser to the victim—a process otherwise known as “victim empowerment.” Using a previously established empowerment framework, the Empowerment Process Model, 2017 PPO statutes for all U.S. states and the District of Columbia ( n = 51) were examined in regard to 23 statutory elements conceptualized to facilitate the process of victim empowerment for initmate partner violence (IPV) victims. Findings demonstrated that there is little consistency across PPO statutes in regard to empowerment facilitators (8.0-18.5, M = 13.5, SD = 2.3). Three elements were found to be consistently empowering by most states: the use of gender-neutral language, inclusion of same-sex couple violence, and adherence to full faith and credit provision of Violence Against Women Act (VAWA). Future research should examine which statutory elements are associated with the greatest increases in victim empowerment, and model PPO language should be developed. Furthermore, in general, PPO research findings must be discussed within the confines of state statutes and limited generalizability across states.
Successful desensitization of a patient with cetuximab hypersensitivity: A case report
Authors: Solduzian Mohammad , Anvari Saeed , Taghvaye Masoumi Hamidreza , Shahi Farhad , Jahangard-Rafsanjani Zahra
Published: August 2018

Background

Severe hypersensitivity reaction is a dangerous adverse drug reaction in patients receiving cetuximab. It requires drug discontinuation and medical management.

Case description

A 48-year-old man, previously diagnosed with metastatic colorectal cancer, was admitted for therapy continuation. During the first infusion of cetuximab, the patient experienced acute signs of hypersensitivity reactions. The treatment team decided to administer cetuximab employing the desensitization protocol.

Conclusions

This study reports a severe hypersensitivity reaction to cetuximab in an adult patient with colorectal cancer. This patient was successfully managed with a new safe and rapid desensitization protocol.
Axisymmetric Boussinesq problem of a transversely isotropic half space with surface effects
Authors: Shen Jing Jin
Published: August 2018

A transversely isotropic half space with surface effects subjected to axisymmetric loadings is investigated in terms of the Lekhnitskii formulism. Surface effects including residual surface stress and surface elasticity are introduced by using the Gurtin–Murdoch continuum model. With the aid of the Hankel transforms, solutions corresponding to several different axisymmetic loadings are derived and used to determine the influence of surface effects on contact stiffness in nanoindentations. Numerical results are provided to show the influence of surface effects and material anisotropy on the material behaviours. Meanwhile, the obtained analytical Green’s functions for two special cases can be used as building blocks for further mixed boundary value problems.
Recurrent destabilising paediatric pelvic arterial haemorrhage: Choosing the embolisation technique that works – A case report
Authors: Ng Bobby KW , Kumar A , Wong Jeffrey KT
Published: August 2018

A 12-year-old male child presented with a history of fall from three floors height with a stable pelvic fracture but destabilised haemodynamically soon after from pelvic arterial haemorrhage. Two attempts of selective embolisation controlled the haemorrhage transiently but recurrent pelvic arterial haemorrhage ensued jeopardising patient’s haemodynamic status. Pelvic arterial haemorrhage was ultimately controlled by a unilateral non-selective embolisation of anterior and posterior divisions of internal iliac artery without any immediate or long-term ischaemic complications. Unilateral non-selective transcatheter arterial embolisation in paediatric pelvic arterial haemorrhage may be used as a viable management option with the potential of evading ischaemic complications and effective in selective embolisation failures.
Real-time implementation of nonlinear optimal-based vibration control for a wind turbine model
Authors: Martynowicz Paweł
Published: August 2018

In the present paper, a real-time implementation of a previously introduced nonlinear optimal-based vibration control method is presented. A vibrating structure, namely a wind turbine tower-nacelle laboratory model equipped with a tuned vibration absorber, is analysed. For control purposes, a magnetorheological damper is used in a tuned vibration absorber system. Force constraints of a magnetorheological damper are an intrinsic part of the implemented nonlinear technique. The aim of the current research is to experimentally investigate the influence of nonlinear optimal-based vibration control law quality index elements’ weights on the vibration attenuation effectiveness along with the magnetorheological damper stroke amplitude, maximum control current or force. As a reference, simple, optimal-based, modified ground-hook law with the sole control objective of primary structure deflection minimisation is used in addition to the passive systems with constant magnetorheological damper current values, proving the benefits of the proposed solution.
Bioinspired control design using cerebellar model articulation controller network for omnidirectional mobile robots
Authors: Jiang Yiming , Yang Chenguang , Wang Min , Wang Ning , Liu Xiaofeng
Published: August 2018

As a learning mechanism that emulates the structure of the cerebellum, cerebellar model articulation controllers have been widely adopted in the control of robotic systems because of the fast learning ability and simple computational structure. In this article, a cerebellar model articulation controller–based neural network controller is developed for an omnidirectional mobile robot. With the powerful learning ability of cerebellar model articulation controller, a cerebellar model articulation controller neural network is constructed to learn the complex dynamics of the omnidirectional mobile robot such that the robot is controlled without a priori knowledge of the robot dynamics. In addition, to overcome the limitation of the neural network controller, a global control technique with a group of smooth switching functions is designed such that the global ultimately uniformly boundedness of cerebellar model articulation controller is achieved instead of conventional semi-global ultimately uniformly boundedness. Moreover, smooth decreasing boundary functions are synthesized into the controller to guarantee the transient control performance. Based on an omnidirectional mobile robot, numerical experiments have been conducted to demonstrate the effectiveness of the proposed cerebellar model articulation controller controller.
Wavelet multi-resolution approximation of time-varying frame structure
Authors: Xiang Min , Xiong Feng , Shi Yuanfeng , Dai Kaoshan , Ding Zhibin
Published: August 2018

Engineering structures usually exhibit time-varying behavior when subjected to strong excitation or due to material deterioration. This behavior is one of the key properties affecting the structural performance. Hence, reasonable description and timely tracking of time-varying characteristics of engineering structures are necessary for their safety assessment and life-cycle management. Due to its powerful ability of approximating functions in the time–frequency domain, wavelet multi-resolution approximation has been widely applied in the field of parameter estimation. Considering that the damage levels of beams and columns are usually different, identification of time-varying structural parameters of frame structure under seismic excitation using wavelet multi-resolution approximation is studied in this article. A time-varying dynamical model including both the translational and rotational degrees of freedom is established so as to estimate the stiffness coefficients of beams and columns separately. By decomposing each time-varying structural parameter using one wavelet multi-resolution approximation, the time-varying parametric identification problem is transformed into a time-invariant non-parametric one. In solving the high number of regressors in the non-parametric regression program, the modified orthogonal forward regression algorithm is proposed for significant term selection and parameter estimation. This work is demonstrated through numerical examples which consider both gradual variation and abrupt changes in the structural parameters.
A time-dependent uncertainty design and optimization strategy using an enhanced Kriging surrogate model
Authors: Jin Xiaojian , Yang Shunqi , Chen Hai , Luo Song
Published: August 2018

Uncertainties exist widely in the time-dependent performance degeneration processes of engineering systems in practice. Generally, in order to simplify the calculation, the random processes of uncertainty information are usually treated as time-independent or monotonic processes. The corresponding uncertainty analysis approaches are time independent. However, in this situation, the failure probabilities of performance can only be considered at the end of structure lifetime. To deal with the above challenge, an enhanced outcrossing rate method using the Kriging interpolation method is proposed in this study. The proposed method can utilize the correlation information between two design variables to predict the stress level and describe the time-dependent degeneration process. An uncertainty-based design and optimization problem of machine tool spindle is utilized to illustrate the effectiveness of the proposed strategy.
Feature extraction for fault diagnosis based on wavelet packet decomposition: An application on linear rolling guide
Authors: Feng Hutian , Chen Rong , Wang Yiwei
Published: August 2018

Linear rolling guide is increasingly being used as the transmission system in computer numerical control machine tools due to its high stiffness, low friction, good ability of precision retaining, and so on. The lubrication of rolling linear guide affects significantly its performance and hence monitoring the lubrication condition during its operation is of great importance. In this article, the relation between different lubrication conditions of linear rolling guide and their corresponding vibration signals is studied. Three lubrication conditions labeled as “Poor,”“Medium,” and “Good” are simulated to represent the actual working conditions. A data acquisition system is set up to acquire the vibration signals corresponding to different conditions. The wavelet packet decomposition is employed to perform time–frequency analysis of the raw signal, after which the energy distribution of the decomposed signals is extracted as the feature. Two linear rolling guides manufactured by different companies are used in the experiments. The results demonstrate that the relation between the energy distribution extracted from vibration signals and lubrication conditions follows a certain rule. A typical feedforward backpropagation neural network is used as the classifier to verify the effectiveness of energy distribution. The average classification accuracy of the network with energy distribution as input is more than 95%. The results show that the lubrication conditions can be characterized by “energy” hidden in the vibration signals and the energy distribution is an appropriate feature that can be used for fault diagnosis of linear rolling guide.
An experimental study on the relationship between torque and preload of threaded connections
Authors: Yu QM , Yang XJ , Zhou HL
Published: August 2018

In order to investigate the relationship between torque and preload during the tightening process by using torque-only control method, a new measuring device was designed in this study. Nickel-based superalloy bolts and nuts of three specifications M8 × 1, M10 × 1.25, and M10 × 1.5 were used in threaded connections to implement the pre-tightening test at room temperature. Pre-tightening tests under four working conditions for every bolt were conducted. Torque-preload curves were drawn according to the test results, and nut factors were obtained by curve fitting method. The effect of surface lubrication and surface roughness on nut factor was analyzed. The results show that the nut factor under lubrication condition is smaller than that without lubrication when the surface roughness remains the same and that under the same lubrication condition, the larger the surface roughness, the greater the nut factor. The results show that the device proposed can be used to measure the preload accurately during the pre-tightening process of threaded connections. Finally, the influence of the screwing times on the nut self-locking torque was studied.
Them and us: Did Democrat inclusiveness and Republican solidarity lead to the 2016 US presidential election outcome?
Authors: Christian Julie , Nayyar Daniella , Riggio Ronald , Abrams Dominic
Published: August 2018

This research examined the role that group dynamics played in the 2016 US presidential election. Just prior to the election, participants were assessed on perceived self-similarity to group members’ views, perception of own leader’s prototypicality, perceptions of social values, and strength of support (attitudes). Results indicated that Democrats were more inclusive, seeing more similarity between themselves and members from the outgroup political party, while Republicans displayed more ingroup solidarity and negative attitudes toward outgroup members. Trump was viewed as a more prototypical leader by Republicans than Clinton was by Democrats. These results may help to explain the perhaps surprising fragility of Democrat voters’ support for Clinton.
Time-dependent forgetting and retrieval practice effects in detailed visual long-term memory
Authors: Mercer Tom , Jones Gemma A
Published: August 2018

Memories—especially those containing fine details—are usually lost over time, but this study assessed whether detailed visual memories can survive a 1-week delay if retrieval practice is provided. In three experiments, participants viewed 300 objects and then completed recognition tests assessing memory for precise object exemplars and their state. The recognition tests occurred immediately after encoding and 1 week later, and required participants to distinguish between a previously seen target object and an incorrect foil. While there was forgetting when participants were tested on different sets of stimuli across the delay, retrieval practice led to an advantage in recognition performance. This effect was not simply due to mere exposure, as retrieval practice boosted recognition beyond a restudy condition, which had a second encoding opportunity but no retrieval practice. Yet more detailed analyses revealed that the effect of retrieval practice was highly dependent upon the type of information being tested (exemplar or state) and the specific foil that was presented. In addition, state information was harder to retain over the delay than exemplar information, suggesting that memory for different properties is forgotten at different rates.
The copula-based method for statistical analysis of step-stress accelerated life test with dependent competing failure modes
Authors: Zhou Yicheng , Lu Zhenzhou , Shi Yan , Cheng Kai
Published: August 2018

Competing risk usually exists in engineering applications; thus, the study of the statistical inference of accelerated life testing with competing failure modes is of great significance. In this article, we address the statistical analysis of a step-stress accelerated life test in the presence of dependent competing failure modes. The dependence structure among distributions of lifetimes is constructed by copula function with unknown copula parameter. The parametric maximum likelihood estimation is developed to obtain the estimates of underlying parameters. The asymptotic standard errors and asymptotic confidence interval of estimates are also obtained by missing information principle. An extensive simulation study and a real data analysis are carried out to observe the performance of the proposed method. The results of the case studies show that our proposed method is valid and effective for the statistical analysis of step-stress accelerated life test with dependent competing failure modes.
Peptide Hp(2–20) accelerates healing of TNBS‐induced colitis in the rat
Authors: Gravina AG , Prevete N , Tuccillo C , De Musis C , Romano L , Federico A , de Paulis A , D’Argenio G , Romano M
Published: August 2018

Background and aims

Hp(2–20), a Helicobacter pylori‐derived peptide interacting with N‐formyl peptide receptors (FPRs), accelerates the healing of gastric injury in rats. Whether Hp(2–20) affects the recovery of inflamed colonic mucosa is unknown. We evaluated whether Hp(2–20) accelerated the healing of 2,4,6‐trinitrobenzenesulfonic acid (TNBS)‐induced colitis and explored the mechanism(s) underlying any such effect.

Methods

Fifteen rats underwent rectal administration of Hp(2–20) 250–500 µg/kg/day, or of its control peptide Hp1 for 10 days, following induction of colitis with TNBS. Macroscopic and histological damage was quantified using predetermined injury scores. FPR1, COX‐2, TNF‐α, TGF‐β, HB‐EGF and tissue transglutaminase (t‐TG) messenger RNA (mRNA) expression in colonic tissue was determined by quantitative polymerase chain reaction; FPR1, TNF‐α and COX‐2 protein levels by Western blotting.

Results

(1) Hp(2–20) accelerated healing of TNBS‐induced colitis compared to controls consistently with the expression of FPRs in colonic mucosa; (2) TNBS upregulated mRNA mucosal expression of COX‐2, TNF‐α, TGF‐β, HB‐EGF and t‐TG and (3) this, with the exception of HB‐EGF, was significantly counteracted by Hp(2–20).

Conclusions

Hp(2–20), an FPR agonist, accelerates the healing of TNBS‐induced colitis in the rat. This effect is associated with a significant reduction in colonic tissue levels of COX‐2, TGF‐β, TNF‐α and t‐TG. We postulate that FPR‐dependent pathways may be involved in the repair of inflamed colonic mucosa.
Meperidine for patients expected to have poor tolerance to esophagogastroduodenoscopy: A double‐blind, randomized, controlled study
Authors: Tseng Chih-Wei , Koo Malcolm , Tseng Kuo-Chih , Hsieh Yu-Hsi
Published: August 2018

Background

Anxious patients and those with poor tolerance to previous esophagogastroduodenoscopy (EGD) usually have poor tolerance for EGD.

Aims

To investigate the effect of meperidine on these patients during EGD.

Methods

A total of 110 patients undergoing diagnostic EGD were randomized to receive either meperidine (n = 55) or placebo (n = 55) before EGD. The primary outcome was patient discomfort scores during esophageal intubation.

Results

Patients in the meperidine group reported less discomfort during esophageal intubation (median score of 5.0 and interquartile range (IQR) 1.5–7.0) compared with the control (median score of 6.0, IQR 5.0–8.5, P = .003). Patients in the meperidine group had better tolerance during the procedure (median score of 2 (IQR 1.0–3.0) versus 3 (IQR 1.0–4.0), P = .048), and the endoscopists reported higher overall satisfaction scores (median score of 9 (IQR 7.0–9.0) versus 8 (IQR 7.0–9.0), P = .043). There was significantly less increase in heart rate and blood pressure during the procedure in the meperidine group than in the placebo group (23 bpm (IQR 9–32) versus 30 bpm (IQR 18–52); P = .006); (7 mmHg (IQR 1–14) versus 18 mmHg (IQR 2–30); P = .008). Connect‐the‐numbers test showed comparable results before and after EGD between the two groups.

Conclusion

For patients expected to have poor tolerance during EGD, meperidine reduced discomfort, decreased cardiovascular distress, and improved endoscopist satisfaction, without adverse effects on their psychomotor function after the procedure.
Bilateral Renal Hypoperfusion Following Motor Vehicle Accident
Authors: Joshi Medha , Aldergash Salah , Hussain Ali , Gulati Rakesh , Malhotra Varun
Published: August 2018

Renal hypoperfusion noted on abdominal computed tomography (CT) scan without any underlying comorbid condition is a rare finding. Most reported cases of renal hypoperfusion have an association with an underlying cardioembolic problem, such as atrial fibrillation, endocarditis, cardiomyopathies, or artificial valve thrombi. We present a case of transient renal hypoperfusion evident on abdominal CT scan following blunt trauma. An 18-year-old male without any significant past medical history presented to the emergency department with the complaint of abdominal pain. The patient reported history of motor vehicle accident 1 week prior to his presentation. He was a front seat passenger wearing a seatbelt when the car went into a ditch. Airbags were deployed and the patient briefly lost consciousness. He presented 1 week later with complaints of generalized abdominal pain, more on the left side that started a few days after his accident, nonradiating, constant, 4/10 intensity. He denied dysuria, hematuria, groin pain, fever, chills, nausea, vomiting, abdominal pain, diarrhea, constipation, decreased oral intake, joint pain, leg swelling, or redness. He denied any medication use or any history of intravenous drug abuse. There was no reported family history of kidney disease or blood clots. Initial laboratory tests, including complete blood count, basic metabolic panel, erythrocyte sedimentation rate, and urinalysis were unremarkable except trace protein on the urinalysis. Contrast-enhanced CT of the abdomen showed multiple, confluent, focal areas of hypoperfusion of the renal parenchyma bilaterally. Given the CT findings of bilateral renal hypoperfusion, the patient was admitted to the hospital and an extensive workup was performed to rule out cardioembolic etiology. Echocardiogram, renal ultrasound, magnetic resonance angiogram of the abdomen, vasculitis panel, and hypercoagulable workup was unremarkable. The CT findings of renal hypoperfusion were considered secondary to transient hypoperfusion from blunt trauma. Abdominal pain resolved with nonsteroidal anti-inflammatory drugs and he was discharged to home. Follow-up abdominal CT scan with contrast obtained a few months later showed normal kidneys with resolution of previously noted renal hypoperfusion. Our case highlights a benign incidental finding of bilateral renal hypoperfusion following motor vehicle accident (with airbag injury), which resolved on follow-up imaging. On literature search, such CT scan findings of transient renal hypoperfusion of unclear significance have not been previously reported. Even though our patient underwent extensive workup to rule out cardioembolic etiology, it may be reasonable to forego such workup following blunt abdominal trauma.
Elastic least-squares reverse time migration with density variations
Authors: Sun Minao , Dong Liangguo , Yang Jizhong , Huang Chao , Liu Yuzhu
Published: August 2018

Elastic least-squares reverse time migration (ELSRTM) is a powerful tool to retrieve high-resolution subsurface images of the earth’s interior. By minimizing the differences between synthetic and observed data, ELSRTM can improve spatial resolution and reduce migration artifacts. However, conventional ELSRTM methods usually assume constant density models, which cause inaccurate amplitude performance in resulting images. To partially remedy this problem, we have developed a new ELSRTM method that considers P- and S-wave velocity and density variations. Our method can simultaneously obtain P- and S-wave velocity and density images with enhanced amplitude fidelity and suppressed parameter crosstalk. In addition, it can provide subsurface elastic impedance images by summing the inverted velocity images with the density image. Compared with the conventional ELSRTM method, our method can improve the quality of final images and provide more accurate reflectivity estimates. Numerical experiments on a horizontal reflector model and a Marmousi-II model demonstrate the effectiveness of this method.
A data-driven amplitude variation with offset inversion method via learned dictionaries and sparse representation
Authors: She Bin , Wang Yaojun , Liang Jiandong , Liu Zhining , Song Chengyun , Hu Guangmin
Published: August 2018

Amplitude variation with offset (AVO) inversion is a typical ill-posed inverse problem. To obtain a stable and unique solution, regularization techniques relying on mathematical models from prior information are commonly used in conventional AVO inversion methods (hence the name model-driven methods). Due to the difference between prior information and the actual geology, these methods often have difficulty achieving satisfactory accuracy and resolution. We have developed a novel data-driven inversion method for the AVO inversion problem. This method can effectively extract useful knowledge from well-log data, including sparse dictionaries of elastic parameters and sparse representation of subsurface model parameters. Lateral continuity of subsurface geology allows for the approximation of model parameters for a work area using the learned dictionaries. Instead of particular mathematical models, a sparse representation is used to constrain the inverse problem. Because no assumption is made about the model parameters, we consider this a data-driven method. The general process of the algorithm is as follows: (1) using well-log data as the training samples to learn the sparse dictionary of each elastic parameter, (2) imposing a sparse representation constraint on the objective function, making the elastic parameters be sparsely represented over the learned dictionary, and (3) solving the objective function by applying a coordinate-descent algorithm. Tests on several synthetic examples and field data demonstrate that our algorithm is effective in improving the resolution and accuracy of solutions and is adaptable to various geologies.
Two-dimensional QT inversion of complex magnetic resonance tomography data
Authors: Jiang Chuandong , Müller-Petke Mike , Wang Qi , Igel Jan
Published: August 2018

Surface nuclear magnetic resonance is a valuable technique that provides insight into the distribution of water content and relaxation time, thus revealing hydraulic properties in the subsurface. Recent research has introduced a new measurement layout that allows for time-efficient imaging of the 2D parameter distribution. Furthermore, for 1D investigations, it has been verified that complex data can provide improved resolution and depth penetration. In our research, we have developed an inverse modeling algorithm based on the QT-inversion scheme that uses the 2D complex magnetic resonance tomography data. We evaluate the uses and limitations of complex data for 2D investigations. By comparing resolution measures, we test this algorithm against state-of-the-art amplitude-based inverse modeling using resolution measures, a rigorous synthetic test, and a field example. Finally, we assess the impact of unknown conductivity and off-resonance excitation on the subsurface image and examined their limitations in field applications. We find that complex inversion is feasible in practice and provides superior results but demands precise knowledge of the true excitation frequency.
Induced polarization response of porous media with metallic particles — Part 8: Influence of temperature and salinity
Authors: Revil André , Coperey Antoine , Mao Deqiang , Abdulsamad Feras , Ghorbani Ahmad , Rossi Magali , Gasquet Dominique
Published: August 2018

We have investigated the influence of temperature and salinity upon the spectral induced polarization of 10 samples including rocks with their mineralization (galena, chalcopyrite) plus sand mixed with semiconductors such as magnetite grains, graphite, and pyrite cubes of two different sizes. Measurements are made in a temperature-controlled bath with a high-precision impedance meter and using NaCl solutions. We cover the temperature range 5°C−50°C and the frequency range [Formula: see text] to 45 kHz. For one large pyrite cube, we also investigated six salinities from 0.1 to [Formula: see text] (at 25°C, NaCl) and three salinities for graphite. The spectra are fitted with a Cole-Cole complex parametric conductivity model for which we provide a physical meaning to the four Cole-Cole parameters. As expected, the Cole-Cole exponent and the chargeability are independent of the temperature and salinity. The instantaneous and steady state (direct current [DC]) conductivities depend on the salinity and temperature. This temperature dependence can be fitted with an Arrhenius law (combining the Stokes-Einstein and Vogel-Fulcher-Tammann equations) with an activation energy in the range of [Formula: see text]. This activation energy is the same as for the bulk pore-water conductivity demonstrating the control by the background electrolyte of these quantities, as expected. The instantaneous and DC conductivities depend on the salinity in a predictable way. The Cole-Cole relaxation time decreases with the temperature and decreases with the salinity. This behavior can be modeled with an Arrhenius law with an apparent activation energy of [Formula: see text]. A finite-element model is used further to analyze the mechanisms of polarization, and it can reproduce the temperature and salinity dependencies observed in the laboratory.
Hydrates on the subsea wellhead in deepwater wells: Study on the growth mechanisms, impacts on drilling safety, and possible solutions
Authors: Zhang Bailing , Yang Jin , Takbiri-Borujeni Ali , Sun Ting , Edrisi Ali Reza , Takbiriboroujeni Hojatollah , Wu Xudong , Liu Hexing , Bo Zhou
Published: August 2018

Hydrate formation poses a risk to deepwater drilling operations. Most current studies on the hydrate formation and its impact on deepwater drilling operations have focused on the risk associated with hydrates inside the wellbore. Few researchers have studied the risk of hydrate formation outside the wellbore, and the risks to deepwater drilling are still unclear. In the South China Sea, there have been several events of hydrate growth on the outer surfaces of the subsea wellhead. The mechanisms of hydrate growth on the outer surface of the subsea wellhead are analyzed, and the gas source is predicted by analyzing the logging data of the adjacent wells. A model for the wellhead stability is developed, and the impacts of hydrate formation on the stability of the subsea wellhead are analyzed. The gas source, temperature, pressure, solid surface roughness, and relative static subsea environment are found to be the key factors in the formation of hydrate in the marine environment. The risk of hydrate formation to wellhead stability is subtle, but to blowout preventer (BOP) could be significant. Hydrates may cause BOP control failure in which the BOP could not be closed in the event of emergency; hydrate formation between the BOP and the wellhead may cause BOP not to be separated from the bottom of the wellhead. A tool was designed for controlling the formation of hydrates, with particular tilt angle and surface roughness. Because the appropriate tilt angle can divert the gas bubbles to avoid the hydrate formations at the wellhead. The designed hydrate control tool successfully mitigates the risks to drilling operations.
Into the Morass: Chesnutt, Antinormativity, and the Queer Politics of Early Jim Crow Literature
Authors: Griffiths Timothy Marshall
Published: August 2018

In this essay I discuss how Charles W. Chesnutt’s The House behind the Cedars—through the tropology of spatialization, illustrations of expansive human intimacy, and indictments of the triangulation of antinormatively gendered and sexed bodies as political capital—intervened in sexual respectability politics in the African American uplift culture of the post-Reconstruction era. In doing so I argue that Chesnutt consecrated the “noble strivings” of sexually antinormative African Americans while simultaneously illustrating the way overdetermined sexual identity politics, especially those in the naturalist literary tradition, diminished black life. With Chesnutt as my starting point, I recommend a return to early Jim Crow novels—particularly those written between the years 1900 and 1905—to suggest their progenitorial role regarding recent turns in queer theory and queer of color critique. In doing so I take steps toward a literary genealogy of queer US sex politics that runs from Plessy v. Ferguson and early Jim Crow, into modernism, and down through women of color feminism of the late 1980s before its formal or academic consecration in contemporary US queer theory. I do this to emphasize an important but still-developing ethic in contemporary queer literary studies: the need to center the study of queer representation and politics on more than homosexuality and especially on blackness.
The Race of Machines: Blackness and Prosthetics in Early American Science Fiction
Authors: Evans Taylor
Published: August 2018

The steam man is a trope of early US science fiction, one inaugurated by the first dime novel Edisonade, Edward Ellis’s 1868 story The Steam Man of the Prairies. Focusing on early steam man stories as well as the historical origin of the trope—Zadoc Dederick’s 1868 invention, dubbed the Newark Steam Man—this essay argues that the course of US science fiction and US technology more generally was shaped by the racial discourses of the Reconstruction. Coming on the heels of the Civil War, the steam man stories, like Dederick’s patent, drew on extant black caricatures to explicitly racialize their central invention, vividly illustrating the afterlife of slavery at the birth of America’s machine culture.
Langston Hughes’s Constructivist Poetics
Authors: Grogan Kristin
Published: August 2018

This essay explores the relationship between Langston Hughes’s 1930s poetry and the Soviet avant-garde theater. It argues that the constructivist theater provides an aesthetic framework through which to read Hughes’s radical poetry. Often read as an artistic failure, Hughes’s 1930s verse—especially his 1938 pamphlet A New Song—represents, I suggest, a formal response to shifting ideologies of poetic labor, namely, an effort to disentangle poetry from capitalist individualism and align it with proletarian collective labor. I argue that Hughes’s socialist poems represent an attempt to refigure poetic labor as a collective act, and I explore the implications that this has for the survival of the lyric poem and lyric modes of address. This article devotes sustained attention to a long-neglected period of Hughes’s career and provides a new reading of the Soviet avant-garde’s influence on US culture in the early twentieth century. Ultimately, it shows that these concerns and tensions are relevant to a broader arc of African American poetic history, from the twentieth century to the poetry of the present day.