bluuebunny/crossref_metadata_2025_split huggingface dataset:
Historical biome distribution and recent human disturbance shape the diversity of arbuscular mycorrhizal fungi
Authors: Pärtel Meelis , Öpik Maarja , Moora Mari , Tedersoo Leho , Szava‐Kovats Robert , Rosendahl Søren , Rillig Matthias C. , Lekberg Ylva , Kreft Holger , Helgason Thorunn , Eriksson Ove , Davison John , de Bello Francesco , Caruso Tancredi , Zobel Martin 
Published: July 2017

Summary

The availability of global microbial diversity data, collected using standardized metabarcoding techniques, makes microorganisms promising models for investigating the role of regional and local factors in driving biodiversity.

Here we modelled the global diversity of symbiotic arbuscular mycorrhizal (AM) fungi using currently available data on AM fungal molecular diversity (small subunit (SSU) ribosomal RNA (rRNA) gene sequences) in field samples. To differentiate between regional and local effects, we estimated species pools (sets of potentially suitable taxa) for each site, which are expected to reflect regional processes. We then calculated community completeness, an index showing the fraction of the species pool present, which is expected to reflect local processes.

We found significant spatial variation, globally in species pool size, as well as in local and dark diversity (absent members of the species pool). Species pool size was larger close to areas containing tropical grasslands during the last glacial maximum, which are possible centres of diversification. Community completeness was greater in regions of high wilderness (remoteness from human disturbance). Local diversity was correlated with wilderness and current connectivity to mountain grasslands.

Applying the species pool concept to symbiotic fungi facilitated a better understanding of how biodiversity can be jointly shaped by large‐scale historical processes and recent human disturbance.
Location, variations, and predictors of epicardial fat mapping using multidetector computed tomography to assist epicardial ventricular tachycardia ablation
Authors: Sourwine Mariaileen , Jeudy Jean , Miller Brian , Vunnam Rama , Imanli Hasan , Mesubi Olurotimi , Etienne‐Mesubi Martine , See Vincent , Shorofsky Stephen , Dickfeld Timm 
Published: July 2017

AbstractBackgroundA significant number of ventricular tachycardia circuits are located close to the epicardial surface and are amendable to epicardial ablation. Epicardial fat often interferes with substrate mapping and ablation, though little is known regarding the distribution of fat and its fluctuation with the cardiac cycle.MethodsWe studied 40 patients who underwent a 64‐slice multidetector computed tomography in order to describe patterns of epicardial fat distribution, variation during cardiac cycle, and clinical predictors of epicardial fat. Multiplanar reconstructions were analyzed during systole and diastole in six cross‐sections. Epicardial fat thickness was measured across multiple wall segments in each view.ResultsEpicardial fat was found to be thicker in areas overlying coronary vasculature (7.8 ± 2.6 mm vs 3.5 ± 0.9 mm, P = 0.001), along with the right ventricular wall (3.9 ± 0.8 mm vs 2.6 ± 0.6 mm, P = 0.001) and the ventricular base (6.1 ± 1.7 mm vs 4.6 ± 1.6 mm, P < 0.01). Epicardial fat thickness increased 27% during systole as compared to diastole (4.9 ± 2.7 mm vs 6.2 ± 3.0 mm, P = 0.04). Variation with cardiac cycle was most evident along the right ventricular wall (3.9 ± 0.8 mm vs 5.0 ± 1.3 mm, P = 0.001) and nonvascular areas (P = 0.001), especially at the ventricular base (3.7 ± 1.1 mm vs 5.3 ± 1.5 mm, P = 0.001). In multivariate logistic regression, we found that age >50 years (P = 0.031) and coronary artery disease (P = 0.023) were statistically correlated with epicardial fat >5‐mm thickness and body mass index > 33 (P = 0.052) nearly so.ConclusionsBaseline epicardial fat thickness >5 mm is common in areas typically targeted during epicardial ablation and further increases during the cardiac cycle. Simple clinical characteristics can identify patients with >5 mm epicardial fat in which preprocedural computed tomography imaging and three‐dimensional fat map reconstruction may facilitate epicardial ablation.
31P NMR Evidence for Peroxide Intermediates in Lipid Emulsion Photooxidations: Phosphine Substituent Effects in Trapping
Authors: Mohapatra Prabhu P. , Chiemezie Callistus O. , Kligman Arina , Kim Michele M. , Busch Theresa M. , Zhu Timothy C. , Greer Alexander 
Published: July 2017

AbstractIntralipid is a lipid emulsion used in photodynamic therapy (PDT) for its light scattering and tissue‐simulating properties. The purpose of this study is to determine whether or not Intralipid undergoes photooxidation, and we have carried out an Intralipid peroxide trapping study using a series of phosphines [2′‐dicyclohexylphosphino‐2,6‐dimethoxy‐1,1′‐biphenyl‐3‐sulfonate, 3‐(diphenylphosphino)benzenesulfonate, triphenylphosphine‐3,3′,3′′‐trisulfonate and triphenylphosphine]. Our new findings are as follows: (1) An oxygen atom is transferred from Intralipid peroxide to the phosphine traps in the dark, after the photooxidation of Intralipid. 3‐(Diphenylphosphino)benzenesulfonate is the most suitable trap in the series owing to a balance of nucleophilicity and water solubility. (2) Phosphine trapping and monitoring by 31P NMR are effective in quantifying the peroxides in H2O. An advantage of the technique is that peroxides are detected in H2O; deuterated NMR solvents are not required. (3) The percent yield of the peroxides increased linearly with the increase in fluence from 45 to 180 J cm−2 based on our trapping experiments. (4) The photooxidation yields quantitated by the phosphines and 31P NMR are supported by the direct 1H NMR detection using deuterated NMR solvents. These data provide the first steps in the development of Intralipid peroxide quantitation after PDT using phosphine trapping and 31P NMR spectroscopy.
Long‐Term Unemployment and the Great Recession: Evidence from UK Stocks and Flows
Authors: Singleton Carl 
Published: July 2017

AbstractLong‐term unemployment more than doubled during the United Kingdom's Great Recession. Only a small fraction of this persistent increase can be accounted for by the changing composition of unemployment across personal and work history characteristics. Through extending a well‐known stocks‐flows decomposition of labour market fluctuations, the cyclical behaviour of participation flows can account for over two‐thirds of the high level of long‐term unemployment following the financial crisis, especially the procyclical flow from unemployment to inactivity. The pattern of these flows and their changing composition suggest a general shift in the labour force attachment of the unemployed during the downturn.
Prevalence ofSalmonellaamong waterfowl along the Texas Gulf coast
Authors: Grigar M. K. , Cummings K. J. , Rankin S. C. 
Published: July 2017

SummaryMigratory waterfowl may play a role in the ecology and transmission of zoonotic pathogens, given their ability to travel long distances and their use of varied habitats. Our objectives were to estimate the prevalence ofSalmonellaamong waterfowl along the Texas Gulf coast and to characterize the isolates. Faecal samples were collected from hunter‐harvested waterfowl at four wildlife management areas from September through November, 2016. Standard bacteriologic culture methods were used to isolateSalmonellafrom samples, and isolates were characterized by serotyping and anti‐microbial susceptibility testing. The apparent prevalence of faecalSalmonellashedding was 0.5% (2/375). Serotypes identified were Thompson and Braenderup, and both isolates were susceptible to all anti‐microbial agents tested. Although faecal contamination of agricultural fields or surface waters could serve as a potential source of zoonoticSalmonellatransmission, waterfowl along the Gulf coast during the fall hunting season appear to pose minimal risk.
Secure Intelligent Radio for Trains (SIRT)
Authors: Bandara K. R. Damindra S. , Kolli Satish , Wijesekara Duminda 
Published: July 2017

American Railroads are planning to complete implementing their Positive Train Control (PTC) systems by 2020. Safety objectives of PTC are to avoid inter-train collisions, train derailments and ensuring railroad worker safety. Under published specifications of I-ETMS (the PTC system developed by Class I freight railroads), the on-board PTC controller communicates with two networks; namely, the Signaling network and the Wayside Interface Unit network to gather navigational information such as the positions of other trains, the status of critical infrastructure (such as switches) and any hazardous conditions that may affect the train path. By design, PTC systems are predicated on having a reliable radio network operating in reserved radio spectrum, although the PTC system itself is designed to be a real-time fail safe distributed control systems. Secure Intelligent Radio for Trains (SIRT) is an intelligent radio that is customized to train operations with the aim of improving the reliability and security of the radio communication network.
SIRT has two tiers. The upper tier has the Master Cognitive Engine (MCE) which communicates with other SIRT nodes to obtain signaling and wayside device information. To do so, the MCE communicates with cognitive engines at the lower tier of SIRT; namely the Cryptographic Cognitive Engine (CCE) (that provide cryptographic security and threat detection) and the Spectrum Management Cognitive Engine (SCE) (that uses spectrum monitoring, frequency hopping and adaptive modulation to ensure the reliability of the radio communication medium). We presented the architecture and the prototype development of the CCE in [1]. This paper presents the design of the MCE and the SCE.
We are currently developing a prototype of the SCE and the MCE and testing the performance of our cognitive radio system under varying radio noise conditions. Our experiments show that SIRT dynamically switches modulation schemes in response to radio noise and switches channels in response to channel jamming.
Locomotive Crash Energy Management Coupling Tests
Authors: Llana Patricia , Tyrell David 
Published: July 2017

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment.
Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. Push-back couplers are designed with trigger loads meant to exceed the expected maximum service loads experienced by conventional couplers. Analytical models are typically used to determine these required trigger loads. Two sets of coupling tests are planned to demonstrate this, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive retrofit with a push-back coupler. These tests will allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests.
The coupling tests of a conventional locomotive have been conducted, the results of which compared favorably with pre-test predictions. In the coupling tests of a CEM-equipped locomotive, the coupling speed for which the push-back coupler (PBC) triggers will be measured. A moving, CEM-equipped locomotive will be coupled to a standing cab car. The coupling speed for the first test will be low, approximately 2 mph. The test will then be repeated with the speed increasing incrementally until the PBC triggers.
This paper describes the fabrication, retrofit, test requirements, and analysis predictions for the CEM coupling tests. The equipment to be tested, track conditions, test procedures, and measurements to be made are described. A model for predicting the longitudinal forces acting on the equipment and couplers has been developed, along with preliminary predictions for the CEM coupling tests.
A Study on Subgrade Pressure Differential Over Regions of Known Substructure Transition as it Relates to Track Geometry
Authors: Palese Joseph W. , Zarembski Allan M. , Hartsough Christopher M. , Thompson Hugh , Palese Michael E. 
Published: July 2017

The support structure beneath railroad tracks may appear to be a simple layering of various materials, but rather, it is a complex system working together to distribute the load of passing trains. It is paramount that this structure maintain its designed support properties not only to preserve component life expectancy but to maintain the safety of the trains traveling over the rails.
During normal operations, track geometry, as evaluated through the standard deviation of various track geometry channels, tends to degrade over time. This is a byproduct of the cyclical loading applied to the track structure by passing trains causing the slow compacting and settling of the ballast and sub-structure. Assuming all variables are held constant, a regular maintenance schedule should bring track geometry back into acceptable limits, but this is generally not the case in real life. In the event that the subgrade cannot support and distribute the pressure caused from the passing train successfully, accelerated track geometry degradation can take place. This accelerated degradation can be further increased when there exists a transition between support strengths which can lead to increased dynamic loading.
A case study in sub-structure pressure management has been devised and applied to a high speed rail line. During a recent track renewal operation where track was maintained down to the subgrade, pressure transducers were placed within the sub-grade layer under both the left and right rails, inside and outside of track regions where sub-structure management has been applied. This test segment was monitored over a period of one year with both pressure and track geometry data being recorded at regular intervals.
This paper will explore the relationship between sub-structure pressure and local track geometry measurements as it relates to the monitored test segment with a region of known subgrade management transition. Numerous numerical techniques will be applied to understand the change over time of the subgrade pressure distribution capability (measured as pressure beneath the rail) and the degradation of various track geometry channels individually over time. Correlation of the pressure data to track geometry data will also be done using both raw data and data processed using numerical techniques. This will lead to an understanding of how the quality of the track support structure, specifically the track support structure’s ability to distribute pressure, can affect the magnitude and degradation rates of various track geometry channels.
Determining the Remaining Prestress Force in a Prestressed Concrete Crosstie
Authors: Scott James D. , Robertson Aaron A. , Peterman Robert J. , Beck B. Terry , Riding Kyle A. , Wu John 
Published: July 2017

The research presented herein focuses on determining the amount of internal prestressing force and bending resistance that is necessary to provide a durable long-term concrete railroad tie. In order to accomplish this, the researchers conducted a systematic evaluation of existing concrete ties that successfully withstood over 25 years of service in track. An experimental method for determining the remaining prestress force in these existing prestressed concrete railroad ties is currently under development.
The ties are first loaded in the upside-down orientation, with supports located at the rail seats, and two point loads applied at the center of the tie. A loading rate of 1,000 lb/min was used to initiate flexural cracking in the center of the tie. Once cracking was observed, the ties underwent 200 cycles of loading to reduce the friction between the prestressing tendons and the concrete. When the cycling was completed, the existing crack was instrumented with an extensometer to measure the Crack Opening Displacement (COD). The ties were loaded once more at 1,000 lb/min to develop a Load vs. COD relation.
A systematic method of determining the load required to reopen the crack from the Load vs. COD relation is being developed using ties cast at a manufacturing plant that were instrumented with internal vibrating-wire strain gages. Using the load required to reopen the crack, along with the known cross-sectional properties at the center of the tie, the remaining prestress force is calculated through equilibrium of forces. This method allows for the determination of the remaining prestress force in a member with known section properties to be obtained through load testing.
Onboard Energy Storage System: Ground Fault Detection and Protection
Authors: Krause Jason , McPhee John 
Published: July 2017

Several Authorities are procuring Hybrid Streetcars with OESS. The energy storage system needs to be protected from ground faults, external and internal to the vehicle. A Hybrid Streetcar has an OESS consisting of either Lithium Batteries or super capacitors, with an OESS converter connected to, or integrated with, the Traction Inverter. During a ground fault of the high voltage circuit, the freewheeling diode in an OESS charger creates a fault path between the energy storage elements and ground.
Typical vehicle designs use a fuse for catastrophic protection, depending on the vehicle ground fault scheme for detection and protection. The vehicle’s primary ground fault detection device is an HSCB, usually connected between the shop switch and traction inverter; the auxiliary inverter is typically protected using a fuse. An HSCB is able to protect typical fault currents seen within the traction chain, but is not designed for OESS fault currents. If a fault occurs the fuse for the catastrophic protection of the OESS will blow before the HSCB will trip, potentially damaging equipment, making the vehicle inoperable. This paper compares alternative methods which can be deployed to detect and protect the OESS from a ground fault.
Accuracy of High Resolution 3D Optical Scanning of Crosstie Geometry for Assessment of Cross-Sectional Parameters and Long-Term Abrasion and Wear
Authors: Beck B. Terry , Robertson Aaron A. , Peterman Robert J. , Riding Kyle A. , Wu John 
Published: July 2017

Current research is attempting to develop a comprehensive understanding of the material and manufacturing characteristics that have caused splitting failures in prestressed concrete railroad ties, in contrast with those characteristics that have resulted in ties that have performed well after many years in track. As part of this effort, a three-dimensional (3D) Optical Scanning System is being used to accurately scan and quantify the surface geometry and volume (abrasion and wear) of a large sample of previously manufactured ties. A commercially-available 3D Laser-Based Optical Scanning System, having a maximum spatial resolution of approximately 0.1mm, is being used to perform the surface scanning operation. The scanning procedure ideally produces an accurate 3D CAD model of the tie geometry, which can then be analyzed to determine the desired geometrical features at any given cross-section. It can likewise yield a measure of the tie volume, the variation of which gives some direct indication of the extent of abrasion and wear.
The feasibility of the scanning system has previously been demonstrated by extracting the detailed longitudinal variation of geometrical cross-section crosstie parameters of a typical CXT tie, including cross-sectional area, centroid, moment of inertia, and the eccentricity of the prestressing wires. These parameters are also known to be of importance to the accurate determination of transfer length from measured surface strain. The CXT tie geometry provides an excellent test case, and a challenge to the optical scanning system, since it has a complex scalloping along its length.
While the basic feasibility of the system operation has been demonstrated, the repeatability of the geometrical information obtained from the overall scanning and subsequent post-processing of surface geometrical data has yet to be assessed.
The main objective of this paper is to first demonstrate the volumetric measurement resolution experimentally by conducting repeated scans of the same tie by the same operator. The experimental scatter in scan results is presented for both cross-section parameter detail and tie volume assessment. The statistical variation in the measured tie volume ideally provides a reasonable measure of the expected volume resolution. In addition to assessing the statistics of these repeated scans, a CXT tie was subjected to induced abrasions of known (measurable) volume for direct comparison with the volume measurements obtained using the optical scanning procedure. This work represents an important next step toward identifying the accuracy of the assessment of abrasion and wear for the large number of ties currently being scanned after having been in long-term service.
Recent Experience on Guideway Intrusion Detection System Implementations
Authors: Schütte Jörg , Scholz Sven 
Published: July 2017

During the last decade, several Public Transportation Operators have started to test and implement technical equipment that shall detect passengers or objects intruding the clearance profile of trains in the station area. The deployed or tested systems typically supervise the track area of subways or light rails and shall stop incoming trains if an obstacle has been detected on the tracks (Guideway Intrusion Detection System, GIDS).
While some scientific and operational publications can be found in the literature for Onboard Obstacle Detection Systems and on different technical solutions for Guideway Intrusion in general, there are virtually none on planning and operations experience for Wayside GIDS in transit applications.
The paper therefore reports on the basic intention and operation of (wayside) GIDS in Unmanned and Driver Operations and findings about detection efficiency and feasibility. Some critical issues had been observed in most implementations and will be discussed in this overview paper.
TelSys GmbH has been working with researchers from TU Dresden on Video GIDS Technology in multiple installations, accumulated substantial statistics of GIDS behavior in diverse field demonstrators (Prague, Berlin, New York City, Munich) and assessed the operational results of GIDS technologies over the years. The Video GIDS is therefore introduced as an illustration example, while the considered aspects are applicable to all GIDS Technologies.