bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tight carbonate gas well deliverability evaluation and reasonable production proration analysis
Authors: Li Jiang , Chen Xianchao , Gao Ping , Zhou Jingchao 
Published: July 2021

AbstractIt is very important to accurately predict the gas well productivity and reasonably allocate the gas production at the early development stage of gas reservoirs. However, both the non-Darcy and stress sensitivity effects have not been investigated in dual-porosity model of tight carbonate gas reservoirs. This paper proposed a new dual-porosity binomial deliverability model and single-well production proration numerical model, which consider the effects of non-Darcy and stress sensitivity. The field gas well deliverability tests data validated the accuracy of the new analytical model, which is a very helpful deliverability method when lacking deliverability test. A geological model was built on the results of the well log, well testing, and well production analysis. Then, a reasonable production proration analysis was conducted based on history matched single-well numerical model. The gas productivity index curve and production–prediction of MX22 several simulation cases were adopted to analyze the reasonable production proration. The results indicate that 1/6 may be suitable for high productivity gas well proration. In addition, the absolute open flow rate from the numerical simulation is higher than that from the new deliverability equation, which also shows that the pressure transient analysis sometimes has some deviation in formation property prediction. It is suggested comprehensively utilizing the analytical binomial model and the single-well numerical model in tight carbonate gas well deliverability evaluation.
Trends in human activity recognition using smartphones
Authors: Ferrari Anna , Micucci Daniela , Mobilio Marco , Napoletano Paolo 
Published: July 2021

AbstractRecognizing human activities and monitoring population behavior are fundamental needs of our society. Population security, crowd surveillance, healthcare support and living assistance, and lifestyle and behavior tracking are some of the main applications that require the recognition of human activities. Over the past few decades, researchers have investigated techniques that can automatically recognize human activities. This line of research is commonly known as Human Activity Recognition (HAR). HAR involves many tasks: from signals acquisition to activity classification. The tasks involved are not simple and often require dedicated hardware, sophisticated engineering, and computational and statistical techniques for data preprocessing and analysis. Over the years, different techniques have been tested and different solutions have been proposed to achieve a classification process that provides reliable results. This survey presents the most recent solutions proposed for each task in the human activity classification process, that is, acquisition, preprocessing, data segmentation, feature extraction, and classification. Solutions are analyzed by emphasizing their strengths and weaknesses. For completeness, the survey also presents the metrics commonly used to evaluate the goodness of a classifier and the datasets of inertial signals from smartphones that are mostly used in the evaluation phase.
Continuous positive airway pressure treatment in sleep apnea: patient compliance and impact on the right heart
Authors: Harańczyk Michał , Konieczyńska Małgorzata , Płazak Wojciech 
Published: July 2021

AbstractObstructive sleep apnea syndrome (OSAS) is considered to be an important predisposing factor for cardiovascular diseases. The main objective of this study was to investigate the impact of CPAP treatment on cardiac structure and function and to assess patient compliance over a long-term course of CPAP treatment. A total of 50 patients diagnosed with moderate-to-severe OSAS based on overnight study, without relevant concomitant diseases were enrolled. Patient compliance, along with echocardiographic and CPAP parameters, was assessed. The average time to follow-up was 38 ± 4.2 months. An increase in tricuspid annular plane systolic excursion (TAPSE) (22.1 ± 4.3–25.5 ± 4.6 mm,p = 0.005) and peak early systolic tricuspid annular velocity (S’) (14 ± 3.2–17.2 ± 5.2 cm/s,p = 0.005) after CPAP treatment was noted. In patients without CPAP, no significant change in right ventricular (RV) contractility was found. There were no significant differences regarding right atrial (RA) and RV diameters, as well as tricuspid regurgitant peak gradient (TRPG) in both groups; however, a predisposition to increased RA size along with RV and tricuspid annulus diameters was revealed. The mean duration of nightly CPAP use was 3 ± 2.3 h/night in all-day analysis and 4.7 ± 2.1 h/night on days with device usage. The non-adherence rate was 57%. The use of effective CPAP therapy may lead to increased RV systolic function in patients with OSAS in long-term observation. However, long-term patient compliance is generally poor. Regardless of CPAP therapy, a gradual increase in heart size is observed.
Optimal design of high efficiency double helical gear based on dynamics model
Authors: Lu Fengxia , Cao Xuechen , Liu Weiping 
Published: July 2021

AbstractA 16-degree-of-freedom dynamic model for the load contact analysis of a double helical gear considering sliding friction is established. The dynamic equation is solved by the Runge–Kutta method to obtain the vibration displacement. The method combines the friction coefficient model based on the elastohydrodynamic lubrication theory with the dynamic model, which provides a theoretical basis for the calculation of the power loss of the transmission system. Moreover, the sensitivity analysis of the parameters that affect the transmission efficiency is carried out, and an optimization method of meshing efficiency is proposed without reducing the bending strength of the gears. This method can directly guide the design of the double helical gear transmission system.
Comment on “Pressure‐to‐Depth Conversion Models for Metamorphic Rocks: Derivation and Applications” by Bauville and Yamato
Authors: Jiang Dazhi 
Published: July 2021

AbstractBauville and Yamato (2021, https://doi.org/10.1029/2020gc009280) (G‐cubed) propose model‐based methods to convert metamorphic pressures to depths based on the claim that pressure data from global (ultra)high‐pressure([U]HP) rocks challenge the lithostatic assumption and support their model which invokes excessive overpressures. It is argued here that the opposite is true: Natural pressure data are fully consistent with the lithostatic assumption. They reflect selection of (U)HP rocks by accessibility and preservation. The data are however inconsistent with the model predictions of Yamato and Brun (2017, https://doi.org/10.1038/ngeo2852) and Bauville and Yamato (2021, https://doi.org/10.1029/2020gc009280). Furthermore, their model requires critical assumptions that are not justified by the principles of rock mechanics and unsupported by microstructures from (U)HP rocks.
Has the Gulf Stream Slowed or Shifted in the Altimetry Era?
Authors: Chi Lequan , Wolfe Christopher L. P. , Hameed Sultan 
Published: July 2021

AbstractThe Gulf Stream (GS) is expected to slow and shift poleward over the next century due to climate change. We investigate whether such changes are already observable in the altimetric record (1993–2018) using along‐track altimetry. Decadal trends in latitude, speed, transport, and width are calculated in stream‐following coordinates to avoid spurious signals due to changes in higher‐frequency GS variability. Statistically significant trends are few and apparently randomly distributed. Further, small changes to the length of the record lead to large changes in the trends and their significance. These results suggest that the current observations are insufficient to detect significant trends in these metrics. If the trends continue at the current rate, detection of trends at more than half of the altimetry tracks would require 22–23 additional years of observations for latitude and transport and 44 additional years for speed.
Representation of Dropsonde‐Observed Atmospheric River Conditions in Reanalyses
Authors: Cobb A. , Delle Monache L. , Cannon F. , Ralph F. M. 
Published: July 2021

AbstractAtmospheric rivers (ARs) are the primary mechanism for mid‐latitude water vapor transport, and are identified by a key variable, integrated water vapor transport (IVT). The ability of atmospheric reanalyses in providing a ground‐truth dataset for the IVT field is assessed by comparing ERA5, MERRA‐2, and JRA‐55 data against a large sample (>1,700) of dropsonde profiles deployed in and around ARs. Bias and error increase with IVT magnitude, although asymmetrically around the AR core. A partitioning of the source of error reveals that humidity contributes more to the difference in IVT above 800 hPa, while wind is the dominant source in the lowest levels (to 950 hPa). This quantification of reanalysis error and bias identifies ERA5 as the dataset with the lowest IVT errors and demonstrates remaining challenges in representing the observed state in ARs.
Enhanced Intraseasonal Variability of the Upper Layers in the Southern Bay of Bengal During the Summer 2016
Authors: Huang Huaming , Wang Dongxiao , Yang Lei , Huang Ke 
Published: July 2021

AbstractIntraseasonal variability (ISV) of the upper 500 m circulation in the southern Bay of Bengal (SBOB) is investigated by using mooring observations and analyzing model outputs. An enhanced ISV is found in the upper 500 m currents during summer 2016. In summer 2016, a boreal summer intraseasonal oscillation (BSISO) propagated northward in tropical Indian Ocean. The intraseasonal easterly anomaly associated with the BSISO forces the equatorial wave to propagate into SBOB, driving the ISV of the upper currents. However, the analysis shows that the enhancement of ISV may be more related to the oceanic instability. During summer 2016, the intensity of the southwest monsoon current (SMC) significantly increased with the position of the flow axis closer to the SBOB's eastern boundary. Energy analysis reveals that the SMC could strengthen the westward propagating Rossby wave through baroclinic and barotropic instability, which can lead to the enhanced ISV of the upper currents in SBOB.
LMMSE channel estimation for OFDM systems with channel correlation function selection
Authors: Mei Kai , Liu Jun , Liu Xiaoran , Xiong Jun , Zhang Xiaoying , Wei Jibo 
Published: July 2021

AbstractIn the linear minimum mean square error (LMMSE) estimation for orthogonal frequency division multiplexing (OFDM) systems, the channel correlation function (CCF) is required. Some methods have been proposed to calculate the CCF. Instead of providing a novel method to obtain the CCF, a scheme is developed for the estimator to select among different CCFs. In this paper, an enhanced LMMSE estimation is proposed that is able to select the best‐matched CCF within a candidate set. To this end, a parameter comparison scheme is proposed, in which the possible channel statistics for the LMMSE estimation can be evaluated using the sampled noise MSE. Analytical expressions are thus derived to indicate the accuracy of the proposed scheme. Furthermore, fuzzy bound is provided as the performance metric, which reflects the resolution of the parameter comparison scheme. As an example of application, the enhanced LMMSE method is used with the block pilot pattern in the OFDM systems, and the possible CCF candidates for typical scenarios are presented. The complexity of the estimator is also analyzed and a simplified parameter comparison algorithm is proposed to reduce the complexity. Finally, the theoretical analysis and performance comparison are demonstrated by simulation experiments.
Fourcade-Figueroa galaxy: A clearly disrupted superthin edge-on galaxy
Authors: Saponara J. , Kamphuis P. , Koribalski B. S. , Benaglia P. 
Published: July 2021

Context. Studies of the stellar and the H I gas kinematics in dwarf and low surface brightness (LSB) galaxies are essential for deriving constraints on their dark matter distribution. Moreover, a key component to unveil in the evolution of LSBs is to determine why some of them can be classified as superthin.
Aims. We aim to investigate the nature of the proto-typical superthin galaxy Fourcade-Figueroa (FF) to understand the role played by the dark matter halo in forming its superthin shape and to investigate the mechanism that explains the observed disruption in the approaching side of the galaxy.
Methods. Combining new H I 21 cm observations obtained with the Giant Metrewave Radio Telescope with archival data from the Australia Telescope Compact Array we were able to obtain sensitive H I observations of the FF galaxy. These data were modelled with a 3D tilted ring model in order to derive the rotation curve and surface brightness density of the neutral hydrogen. We subsequently used this model, combined with a stellar profile from the literature, to derive the radial distribution of the dark matter in the FF galaxy. Additionally, we used a more direct measurement of the vertical H I gas distribution as a function of the galactocentric radius to determine the flaring of the gas disk.
Results. For the FF galaxy, the Navarro-Frenk-White dark matter distribution provides the best fit to the observed rotation curve. However, the differences with a pseudo-isothermal halo are small. Both models indicate that the core of the dark matter halo is compact. Even though the FF galaxy classifies as superthin, the gas thickness about the galactic centre exhibits a steep flaring of the gas that agrees with the edge of the stellar disk. In addition, FF is clearly disrupted towards its north-west side, clearly observed at optical and H I wavelengths. As suggested previously in the literature, the compact dark matter halo might be the main cause for the superthin structure of the stellar disk in FF. This idea is strengthened through the detection of the disruption; the fact that the galaxy is disturbed also appears to support the idea that it is not isolation that causes its superthin structure.
Cu-Catalyzed C–H Activation Reaction: One-Pot Direct Synthesis of Xanthine and Uric Acid Derivatives from 5-Bromouracil
Authors: Roy Brindaban , Rahaman Habibur , Hazra Somjit , Mondal Biplab 
Published: July 2021

AbstractA one-pot direct synthesis of xanthine and uric acid derivates is reported. This simple yet efficient methodology illustrates concurrent formation of two C–N bonds using CuBr2 as catalyst and one of those C–N bonds is formed by uracil C6–H bond activation.
Evaluation and Management of Early Onset Genetic Obesity in Childhood
Authors: Malhotra Sonali , Sivasubramanian Ramya , Srivastava Gitanjali 
Published: July 2021

AbstractOne in five children and adolescents in the United States are diagnosed with obesity and nearly 6% of them are being classified under the severe obesity category. With over 7% of severe obesity being attributed to genetic disorders, in this review we aim to focus on monogenic and syndromic obesity: its etiology, wide spectrum of clinical presentation, criticalness of early identification, and limited management options. Advanced genetic testing methods including microarray and whole genome sequencing are imperative to identify the spectrum of mutations and develop targeted treatment strategies including personalized multidisciplinary care, use of investigational drugs, and explore surgical options in this unique subset of severe pediatric obesity.
Total Synthesis of Macaranin B
Authors: Matsumoto Shintaro , Aoyama Akio , Wakamori Shinnosuke , Yamada Hidetoshi 
Published: July 2021

ABSTRACT
This study describes the total synthesis of macaranin B, a naturally occurring ellagitannin containing 1-O-galloyl and 3,6-O-macaranoyl groups in an axial-rich d-glucose. The key steps of the synthesis include an oxidative coupling reaction of galloyl groups with 1,2,4-orthoacetylglucose moiety and oxa-Michael addition/elimination using an orthoquinone monoketal. This facilitates the construction of the macaranoyl group and the first total synthesis of macaranin B.
Characterization of 3-isopropylmalate dehydrogenase from extremely halophilic archaeon Haloarcula japonica
Authors: Nagaoka Shintaro , Sugiyama Noriko , Yatsunami Rie , Nakamura Satoshi 
Published: July 2021

ABSTRACT
3-Isopropylmalate dehydrogenase (IPMDH) catalyzes oxidative decarboxylation of (2R, 3S)-3-isopropylmalate to 2-oxoisocaproate in leucine biosynthesis. In this study, recombinant IPMDH (HjIPMDH) from an extremely halophilic archaeon, Haloarcula japonica TR-1, was characterized. Activity of HjIPMDH increased as KCl concentration increased, and the maximum activity was observed at 3.0 m KCl. Analytical ultracentrifugation revealed that HjIPMDH formed a homotetramer at high KCl concentrations, and it dissociated to a monomer at low KCl concentrations. Additionally, HjIPMDH was thermally stabilized by higher KCl concentrations. This is the first report on haloarchaeal IPMDH.
Metabolic Syndrome Trajectories and Objective Physical Performance in Mid-to-Early Late Life: The Study of Women’s Health Across the Nation (SWAN)
Authors: Napoleone Jenna M , Boudreau Robert M , Lange-Maia Brittney S , El Khoudary Samar R , Ylitalo Kelly R , Kriska Andrea M , Karvonen-Gutierrez Carrie A , Strotmeyer Elsa S 
Published: July 2021

AbstractBackgroundLittle is known about how adverse, midlife metabolic profiles affect future physical functioning. We hypothesized that a higher number of midlife metabolic syndrome (MetS) components are associated with poorer physical performance in early old age for multiethnic women.MethodsMetS status from 1996 to 2011 (8 visits) and objective physical performance in 2015/2016 (Short Physical Performance Battery [SPPB; 0–12], 40-foot walk [meter/second], 4-meter gait speed [meter/second], chair stands [seconds], stair climb [seconds]) were assessed in the Study of Women’s Health Across the Nation (SWAN; n = 1722; age 65.4 ± 2.7 years; 26.9% African American, 10.1% Chinese, 9.8% Japanese, 5.5% Hispanic). Poisson latent class growth modeling identified MetS component trajectory groups: none (23.9%), 1 = low-MetS (28.7%), 2 = mid-MetS (30.9%), and ≥3 = high-MetS (16.5%). Adjusted linear regression related MetS groups to physical performance outcomes.ResultsHigh-MetS versus none had higher body mass index, pain, financial strain, and lower physical activity and self-reported health (p &lt; .0001). Compared with White, African American and Hispanic women were more likely to be in the high-MetS groups and had worse physical functioning along with Chinese women (SPPB, chair stand, stair climb, and gait speed—not Hispanic). After adjustments, high-MetS versus none demonstrated significantly worse 40-ft walk (β: −0.08; 95% CI: −0.13, −0.03), gait speed (β: −0.09; 95% CI: −0.15, −0.02), SPPB (β: −0.79; 95% CI: −1.15, −0.44), and chair stands (β: 0.69; 95% CI: 0.09, 1.28), but no difference in stair climb.ConclusionsMidlife MetS groups were related to poor physical performance in early old age multiethnic women. Midlife management of metabolic function may improve physical performance later in life.
Automatic first-arrival picking method via intelligent Markov optimal decision processes
Authors: Luo Fei , Feng Bo , Wang Huazhong 
Published: July 2021

Abstract
Picking the first arrival is an important step in seismic processing. The large volume of the seismic data calls for automatic and objective picking. In this paper, we formulate first-arrival picking as an intelligent Markov decision process in the multi-dimensional feature attribute space. By designing a reasonable model, the global optimization is carried out in the reward function space to obtain the path with the largest cumulative reward value, to achieve the purpose of automatically picking up the first arrival. The state-value function contains a distance-related discount factor γ, which enables the Markov decision process to pick up the first-arrival continuity to consider the lateral continuity of the seismic data and avoid the bad trace information in the seismic data. On this basis, the method of this paper further introduces the optimized model that is a fuzzy clustering-based multi-dimensional attribute reward function and structure-based Gaussian stochastic policy, thereby reducing the difficulty of model design, and making the seismic data pick up more accurately and automatically. Testing this approach in the field seismic data reveals its properties and shows it can automatically pick up more reasonable first arrivals and has a certain quality control ability, especially the first-arrival energy is weak (the signal-to-noise ratio is low) or there are adjacent complex waveforms in the shallow layer.
OpenFOAM solver of the methane behaviour near the coal mine tunnelling face and its application
Authors: Li Chengwu , Zhao Yuechao , He Yonghang 
Published: July 2021

Abstract
The methane near a tunnelling face seriously affects production safety in coal mines. A model considering methane seepage, adsorption, desorption and coal damage processes was established in this research. The open field operation and manipulation (OpenFOAM) solver was compiled to numerically solve the established model. The model is validated against data published in a previous theoretical study. The solver was used to investigate the effect of different parameters on methane emission regularity. This solver demonstrates that the effects of the original stress, coal cohesion and coal internal friction angle on the methane emission rate are limited, but their effects on the width of the fractured zone and effective stress are great. The effects of the initial methane pressure and coal adsorption parameters on the methane emission rate are also notable, but their effects on the width of the fractured zone and effective stress are limited.
Artificial cell factory design for shikimate production in Escherichia coli
Authors: Lee Han-Na , Seo Seung-Yeul , Kim Hey-Jin , Park Ji-Hoon , Park Eunhwi , Choi Si-Sun , Lee Sang Joung , Kim Eung-Soo 
Published: July 2021

Abstract
Shikimate is a key intermediate in high demand for synthesizing valuable antiviral drugs, such as the anti-influenza drug and oseltamivir (Tamiflu®). Microbial-based shikimate production strategies have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. Although shikimate biosynthesis has been reported in several engineered bacterial species, the shikimate production yield is still unsatisfactory. This study designed an Escherichia coli cell factory and optimized the fed-batch culture process to achieve a high titer of shikimate production. Using the previously constructed dehydroshikimate (DHS)-overproducing E. coli strain, two genes (aroK and aroL) responsible for converting shikimate to the next step were disrupted to facilitate shikimate accumulation. The genes with negative effects on shikimate biosynthesis, including tyrR, ptsG, and pykA, were disrupted. In contrast, several shikimate biosynthetic pathway genes, including aroB, aroD, aroF, aroG, and aroE, were overexpressed to maximize the glucose uptake and intermediate flux. The shiA involved in shikimate transport was disrupted, and the tktA involved in the accumulation of both PEP and E4P was overexpressed. The rationally designed shikimate-overproducing E. coli strain grown in an optimized medium produced approximately 101 g/l of shikimate in 7-l fed-batch fermentation, which is the highest level of shikimate production reported thus far. Overall, rational cell factory design and culture process optimization for microbial-based shikimate production will play a key role in complementing traditional plant-derived shikimate production processes.