bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technical Note: Measuring contrast‐ and noise‐dependent spatial resolution of an iterative reconstruction method in CT using ensemble averaging
Authors: Yu Lifeng , Vrieze Thomas J. , Leng Shuai , Fletcher Joel G. , McCollough Cynthia H. 
Published: April 2015

Purpose:The spatial resolution of iterative reconstruction (IR) in computed tomography (CT) is contrast‐ and noise‐dependent because of the nonlinear regularization. Due to the severe noise contamination, it is challenging to perform precise spatial‐resolution measurements at very low‐contrast levels. The purpose of this study was to measure the spatial resolution of a commercially available IR method using ensemble‐averaged images acquired from repeated scans.Methods:A low‐contrast phantom containing three rods (7, 14, and 21 HU below background) was scanned on a 128‐slice CT scanner at three dose levels (CTDIvol = 16, 8, and 4 mGy). Images were reconstructed using two filtered‐backprojection (FBP) kernels (B40 and B20) and a commercial IR method (sinogram affirmed iterative reconstruction, SAFIRE, Siemens Healthcare) with two strength settings (I40‐3 and I40‐5). The same scan was repeated 100 times at each dose level. The modulation transfer function (MTF) was calculated based on the edge profile measured on the ensemble‐averaged images.Results:The spatial resolution of the two FBP kernels, B40 and B20, remained relatively constant across contrast and dose levels. However, the spatial resolution of the two IR kernels degraded relative to FBP as contrast or dose level decreased. For a given dose level at 16 mGy, the MTF50% value normalized to the B40 kernel decreased from 98.4% at 21 HU to 88.5% at 7 HU for I40‐3 and from 97.6% to 82.1% for I40‐5. At 21 HU, the relative MTF50% value decreased from 98.4% at 16 mGy to 90.7% at 4 mGy for I40‐3 and from 97.6% to 85.6% for I40‐5.Conclusions:A simple technique using ensemble averaging from repeated CT scans can be used to measure the spatial resolution of IR techniques in CT at very low contrast levels. The evaluated IR method degraded the spatial resolution at low contrast and high noise levels.
Impact of positional difference on the measurement of breast density using MRI
Authors: Chen Jeon‐Hor , Chan Siwa , Tang Yi‐Ting , Hon Jia Shen , Tseng Po‐Chuan , Cheriyan Angela T. , Shah Nikita Rakesh , Yeh Dah‐Cherng , Lee San‐Kan , Chen Wen‐Pin , McLaren Christine E. , Su Min‐Ying 
Published: April 2015

Purpose:This study investigated the impact of arms/hands and body position on the measurement of breast density using MRI.Methods:Noncontrast‐enhanced T1‐weighted images were acquired from 32 healthy women. Each subject received four MR scans using different experimental settings, including a high resolution hands‐up, a low resolution hands‐up, a high resolution hands‐down, and finally, another high resolution hands‐up after repositioning. The breast segmentation was performed using a fully automatic chest template‐based method. The breast volume (BV), fibroglandular tissue volume (FV), and percent density (PD) measured from the four MR scan settings were analyzed.Results:A high correlation of BV, FV, and PD between any pair of the four MR scans was noted (r > 0.98 for all). Using the generalized estimating equation method, a statistically significant difference in mean BV among four settings was noted (left breast, score test p = 0.0056; right breast, score test p = 0.0016), adjusted for age and body mass index. Despite differences in BV, there were no statistically significant differences in the mean PDs among the four settings (p > 0.10 for left and right breasts). Using Bland–Altman plots, the smallest mean difference/bias and standard deviations for BV, FV, and PD were noted when comparing hands‐up high vs low resolution when the breast positions were exactly the same.Conclusions:The authors’ study showed that BV, FV, and PD measurements from MRI of different positions were highly correlated. BV may vary with positions but the measured PD did not differ significantly between positions. The study suggested that the percent density analyzed from MRI studies acquired using different arms/hands and body positions from multiple centers can be combined for analysis.
A dual‐Kinect approach to determine torso surface motion for respiratory motion correction in PET
Authors: Heß Mirco , Büther Florian , Gigengack Fabian , Dawood Mohammad , Schäfers Klaus P. 
Published: April 2015

Purpose:Respiratory gating is commonly used to reduce blurring effects and attenuation correction artifacts in positron emission tomography (PET). Established clinically available methods that employ body‐attached hardware for acquiring respiration signals rely on the assumption that external surface motion and internal organ motion are well correlated. In this paper, the authors present a markerless method comprising two Microsoft Kinects for determining the motion on the whole torso surface and aim to demonstrate its validity and usefulness—including the potential to study the external/internal correlation and to provide useful information for more advanced correction approaches.Methods:The data of two Kinects are used to calculate 3D representations of a patient's torso surface with high spatial coverage. Motion signals can be obtained for any position by tracking the mean distance to a virtual camera with a view perpendicular to the surrounding surface. The authors have conducted validation experiments including volunteers and a moving high‐precision platform to verify the method's suitability for providing meaningful data. In addition, the authors employed it during clinical 18F‐FDG‐PET scans and exemplarily analyzed the acquired data of ten cancer patients. External signals of abdominal and thoracic regions as well as data‐driven signals were used for gating and compared with respect to detected displacement of present lesions. Additionally, the authors quantified signal similarities and time shifts by analyzing cross‐correlation sequences.Results:The authors’ results suggest a Kinect depth resolution of approximately 1 mm at 75 cm distance. Accordingly, valid signals could be obtained for surface movements with small amplitudes in the range of only few millimeters. In this small sample of ten patients, the abdominal signals were better suited for gating the PET data than the thoracic signals and the correlation of data‐driven signals was found to be stronger with abdominal signals than with thoracic signals (average Pearson correlation coefficients of 0.74 ± 0.17 and 0.45 ± 0.23, respectively). In all cases, except one, the abdominal respiratory motion preceded the thoracic motion—a maximum delay of approximately 600 ms was detected.Conclusions:The method provides motion information with sufficiently high spatial and temporal resolution. Thus, it enables meaningful analysis in the form of comparisons between amplitudes and phase shifts of signals from different regions. In combination with a large field‐of‐view, as given by combining the data of two Kinect cameras, it yields surface representations that might be useful in the context of motion correction and motion modeling.
New and old about renormalons: In memoriam Kolya Uraltsev
Authors: Shifman M. 
Published: April 2015

I summarize what we know of renormalons from the 1970s and 80s: their uses and theoretical status. It is emphasized that renormalons in QCD are closely related to the Wilsonean operator product expansion (OPE) — a setup ideally suited for dealing with the factorially divergent series reflecting infrared dynamics. I discuss a breakthrough proposal due to Uraltsev et al. to use renormalons to evaluate nonperturbative (power) corrections in the processes without OPE. Some fresh ideas which were put forward recently are briefly discussed too, with emphasis on a possible relationship between resurgence via trans-series and OPE.This article is devoted to the memory of my friend Kolya Uraltsev. I should emphasize that these are my personal recollections. Other people who closely knew Kolya may or may not agree with my opinions.
Measuring the Strength of the Semantic Relationship Between Words
Authors: Stanchev Lubomir 
Published: April 2015

We propose a novel way for extracting the strength of the semantic relationship between words from semi-structured sources, such as WordNet. Unlike existing approaches that only explore the structured information (e.g., the hypernym relationship in WordNet), we present a framework that allows us to utilize all available information, including natural text descriptions. Our approach constructs a similarity graph that stores the strength of the semantic relationship between words. Specifically, an edge between two words describes the probability that someone who is interested in resources about the first word will be also interested in resources about the second word. Note that the graph is asymmetric because the probability that someone is interested in the second word given that they are interested in the first word is not the same as the probability that they are interested in the first word given that they are interested in the second word. The similarity between any two words in the graph can be computed as a function of the directed paths between the two nodes in the graph that represent the words. We evaluate the quality of the data in the similarity graph by comparing the similarity of pairs of words using our software that uses the graph with results of studies that are performed with human subjects. To the best of our knowledge, our software produces better correlation with the results of both the Miller and Charles study and the WordSimilarity-353 study than any other published research. We also present an extended evaluation section that describes how the different heuristics that we use affect the correlation score.
The Sensitivity of Hurricane Irene to Aerosols and Ocean Coupling: Simulations with WRF Spectral Bin Microphysics
Authors: Lynn Barry H. , Khain Alexander P. , Bao Jian Wen , Michelson Sara A. , Yuan Tianle , Kelman Guy , Rosenfeld Daniel , Shpund Jacob , Benmoshe Nir 
Published: April 2015

Abstract
Hurricane Irene (2011) moved northward along the eastern coast of the United States and was expected to cause severe wind and flood damage. However, the hurricane weakened much faster than was predicted. Moreover, the minimum pressure in Irene occurred, atypically, about 40 h later than the time of maximum wind speed. Possible reasons for Irene’s weakening and the time shift between maximum wind and minimum central pressure were studied in simulations using WRF with spectral bin microphysics (WRF-SBM) with 1-km grid spacing and ocean coupling. Both ocean coupling and aerosol distribution/concentration were found to influence Irene’s development. Without ocean coupling or with ocean coupling and uniform aerosol distribution, the simulated maximum wind occurred at about the same time as the minimum pressure. With ocean coupling and nonuniform spatial aerosol distributions caused by aerosols from the Saharan air layer (band) and the continental United States, the maximum wind occurred about 40 h before the simulated minimum pressure, in agreement with observations. Concentrations of aerosols of several hundred per cubic centimeter in the inner core were found to initially cause convection invigoration in the simulated eyewall. In contrast, a weakening effect dominated at the mature and the decaying stages, when aerosols from the band and land intensified convection at the simulated storm’s periphery. Simulations made with 3-km instead of 1-km grid spacing suggest that cloud-scale processes interactions are required to correctly simulate the timing differences between maximum wind and minimum pressure.
Stationary Eddies and the Zonal Asymmetry of Net Precipitation and Ocean Freshwater Forcing
Authors: Wills Robert C. , Schneider Tapio 
Published: April 2015

Abstract
Transport of water vapor in the atmosphere generates substantial spatial variability of net precipitation (precipitation minus evaporation). Over half of the total spatial variability in annual-mean net precipitation is accounted for by deviations from the zonal mean. Over land, these regional differences determine differences in surface water availability. Over oceans, they account, for example, for the Pacific–Atlantic difference in sea surface salinity, with implications for the deep overturning circulation. This study analyzes the atmospheric water budget in reanalyses from ERA-Interim and MERRA, to investigate which physical balances lead to zonal variation in net precipitation. It is found that the leading-order contribution is zonal variation in stationary-eddy vertical motion. Transient eddies modify the pattern of zonally anomalous net precipitation by moving moisture from the subtropical and tropical oceans onto land and poleward across the Northern Hemisphere storm tracks. Zonal variation in specific humidity and stationary-eddy horizontal advection play a secondary role. The dynamics leading to net precipitation via vertical motion in stationary eddies can be understood from a lower-tropospheric vorticity budget. The large-scale variations of vertical motion are primarily described by Sverdrup balance and Ekman pumping, with some modification by transient eddies. These results suggest that it is important to understand changes in stationary eddies and their influence on the zonal variation of transient eddy fluxes, in order to understand regional changes in net precipitation. They highlight the relative importance of different atmospheric mechanisms for the freshwater forcing of the North Pacific and North Atlantic.
Service Research Priorities in a Rapidly Changing Context
Authors: Ostrom Amy L. , Parasuraman A. , Bowen David E. , Patrício Lia , Voss Christopher A. 
Published: April 2015

The context in which service is delivered and experienced has, in many respects, fundamentally changed. For instance, advances in technology, especially information technology, are leading to a proliferation of revolutionary services and changing how customers serve themselves before, during, and after purchase. To understand this changing landscape, the authors engaged in an international and interdisciplinary research effort to identify research priorities that have the potential to advance the service field and benefit customers, organizations, and society. The priority-setting process was informed by roundtable discussions with researchers affiliated with service research centers and networks located around the world and resulted in the following 12 service research priorities: stimulating service innovation, facilitating servitization, service infusion, and solutions, understanding organization and employee issues relevant to successful service, developing service networks and systems, leveraging service design, using big data to advance service, understanding value creation, enhancing the service experience, improving well-being through transformative service, measuring and optimizing service performance and impact, understanding service in a global context, and leveraging technology to advance service. For each priority, the authors identified important specific service topics and related research questions. Then, through an online survey, service researchers assessed the subtopics’ perceived importance and the service field’s extant knowledge about them. Although all the priorities and related topics were deemed important, the results show that topics related to transformative service and measuring and optimizing service performance are particularly important for advancing the service field along with big data, which had the largest gap between importance and current knowledge of the field. The authors present key challenges that should be addressed to move the field forward and conclude with a discussion of the need for additional interdisciplinary research.
Pediatric Cardiac Tumors
Authors: Linnemeier Laura , Benneyworth Brian D. , Turrentine Mark , Rodefeld Mark , Brown John 
Published: April 2015

Background: Cardiac tumors in children are rare. Of the cases reported in the literature, nearly all are benign and managed conservatively. Methods: This is a retrospective, observational study of pediatric patients <18 years who presented for surgical evaluation of a cardiac tumor, between 1969 and 2014 at a tertiary care children’s hospital. Presentation, pathology, management, and outcomes were evaluated. Results: Over the last 45 years, 64 patients were evaluated for surgical resection of a cardiac tumor. Rhabdomyoma was the most common neoplasm (58%), and 17% of the tumors had malignant pathologies. While 42% of benign cardiac neoplasms required surgical intervention for significant hemodynamic concerns, 73% of malignant neoplasms underwent radical excision, if possible, followed by adjuvant chemotherapy. Despite a 37% mortality in patients with malignant pathology, an aggressive surgical approach can yield long-term survival in some patients. There were no deaths among patients with benign tumors and 17% had postoperative complications mostly related to mitral regurgitation. Conclusion: Cardiac tumors in children are rare but can be managed aggressively with good outcomes. Benign tumors have an excellent survival with most complications related to tumor location. Malignant tumors have a high mortality rate, but surgery and adjuvant chemotherapy allow for prolonged survival in selected patients.
Outcome Following Augmentation of Superior Cavopulmonary Blood Flow With an Arteriovenous Fistula
Authors: Chanana Nitin , Day Ronald W. , McGough Edwin C. , Burch Phillip T. 
Published: April 2015

Background: Axillary or brachial arteriovenous fistulae are occasionally created to improve systemic oxygen saturation in patients with functionally univentricular circulation after superior cavopulmonary anastomosis. Different techniques of fistula construction may account for the conflicting results. We sought to determine the impact of axillary arteriovenous fistula on systemic oxygen saturation and survival before subsequent palliation or heart transplantation. Methods: Medical records of patients who underwent a side-to-side anastomosis between an adjacent axillary artery and vein for cyanosis after superior cavopulmonary anastomosis between 1991 and 2010 were reviewed. Results: The median age (n = 23) at the time of fistula creation was 54 months (4-278 months). There was no operative mortality. The median duration of fistula patency was 48 months (1-174 months). Oxygen saturation improved from 71% ± 10% preoperatively to 84% ± 4% early ( P < .05) and 81% ± 4% long term after the arteriovenous fistula ( P < .05). Twelve patients underwent additional surgery (total cavopulmonary anastomosis 6, partial biventricular repair 2, and heart transplantation 4) after an interval of 10 to 141 months. Six patients are alive with a patent fistula without subsequent interventions after an interval of 48 to 174 months. Two patients with spontaneous closure or device closure of the fistula are alive after an interval of 76 to 80 months without subsequent interventions. Three deaths occurred with a patent fistula without subsequent interventions after an interval of 1 to 84 months. Conclusions: Systemic oxygen saturation improved with creation of an axillary arteriovenous fistula after superior cavopulmonary anastomosis. The fistula extended the duration of this stage of palliation without precluding the option for additional palliation or heart transplantation.
Driving Forces behind Transformaion of Land Use in Southwest Birbhum District, West Bengal, India
Authors: Ghosh Tanusree 
Published: April 2015

The Southwest Birbhum District (SWBD) is socio-economically and culturally a rural, backward area. As a consequence of the combined effect of poor physical set-up and very slow rate of socio-economic, cultural and technological evolution, land use characteristics in the study area remain more or less stagnant with some areal interchange among broad land use categories. However, there have been occurring micro-level changes in land use techniques and practices. There has been occurring proliferation of some profit-oriented, illegal, unscientific and unsustainable land use practices at the cost of valuable natural resources which would otherwise be utilised in a scientific way and thus would be sustainable to the regional economy, society and environment. Some of these activities are illegal coal mining activity, illegal coke factory, brick kiln and poppy seed cultivation and so on.  In this context, the present study aims to find out the regional specificities of the study area, changing pattern of land use practices in the study area, the physical and anthropogenic driving forces behind land use changes and to suggest some remedial measures.
10-W pulsed operation of substrate emitting photonic-crystal quantum cascade laser with very small divergence
Authors: Yao Dan-Yang , Zhang Jin-Chuan , Cathabard Olivier , Zhai Shen-Qiang , Liu Ying-Hui , Jia Zhi-Wei , Liu Feng-Qi , Wang Zhan-Guo 
Published: April 2015

Abstract
High-power broad area substrate emitting photonic-crystal distributed feedback (DFB) quantum cascade lasers (QCLs) emitting around 4.73 μm is reported. Two-dimensional centered rectangular photonic-crystal (CRPC) grating is introduced to enhance optical coherence in large area device. Main lobe far-field radiation pattern with a very small divergence angle of about 0.65° × 0.31° is obtained. A record peak output power for vertical emitting QCLs exceeding 10 W is obtained with high reflectivity (HR) coating. Robust single longitudinal mode emission with a side mode suppression ratio (SMSR) of 30 dB is continuously tunable by the heat sink temperature up to 65°C.
Active site formation mechanism of carbon-based oxygen reduction catalysts derived from a hyperbranched iron phthalocyanine polymer
Authors: Hiraike Yusuke , Saito Makoto , Niwa Hideharu , Kobayashi Masaki , Harada Yoshihisa , Oshima Masaharu , Kim Jaehong , Nabae Yuta , Kakimoto Masa-aki 
Published: April 2015

Abstract
Carbon-based cathode catalysts derived from a hyperbranched iron phthalocyanine polymer (HB-FePc) were characterized, and their active-site formation mechanism was studied by synchrotron-based spectroscopy. The properties of the HB-FePc catalyst are compared with those of a catalyst with high oxygen reduction reaction (ORR) activity synthesized from a mixture of iron phthalocyanine and phenolic resin (FePc/PhRs). Electrochemical measurements demonstrate that the HB-FePc catalyst does not lose its ORR activity up to 900°C, whereas that of the FePc/PhRs catalyst decreases above 700°C. Hard X-ray photoemission spectra reveal that the HB-FePc catalysts retain more nitrogen components than the FePc/PhRs catalysts between pyrolysis temperatures of 600°C and 800°C. This is because the linked structure of the HB-FePc precursor has high thermostability against nitrogen desorption. Consequently, effective doping of active nitrogen species into the sp

2
carbon network of the HB-FePc catalysts may occur up to 900°C.
The effect of cyclic martensitic transformations on diffusion of cobalt atoms in Fe-18wt.%Mn-2wt.%Si alloy
Authors: Danilchenko Vitaliy E , Mazanko Vladimir F , Filatov Alexander V , Iakovlev Viktor E 
Published: April 2015

Abstract
Diffusion characteristics of cobalt atoms were investigated using radioactive isotope method in phase-hardened Fe-18wt.%Mn-2wt.%Si alloy. The observed significant increase of diffusion coefficient of cobalt atoms under the cyclic γ-ε-γ martensitic transformations was due to the action of two independent mechanisms - an athermal one and a thermally activated one. The first one arose from the direct γ-ε and the reverse ε-γ transformations with corresponding direct and reverse lattice shears during alternating stresses and simultaneous lattice restructuring. Another mechanism arose under the diffusion annealing of the phase-hardened alloy.