bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrete-time random walks and Lévy flights on arbitrary networks: when resetting becomes advantageous?
Authors: Riascos Alejandro P , Boyer Denis , Mateos José L 
Published: May 2022

Abstract
The spectral theory of random walks on networks of arbitrary topology can be readily extended to study random walks and Lévy flights subject to resetting on these structures. When a discrete-time process is stochastically brought back from time to time to its starting node, the mean search time needed to reach another node of the network may be significantly decreased. In other cases, however, resetting is detrimental to search. Using the eigenvalues and eigenvectors of the transition matrix defining the process without resetting, we derive a general criterion for finite networks that establishes when there exists a non-zero resetting probability that minimizes the mean first passage time (MFPT) at a target node. Right at optimality, the coefficient of variation of the first passage time is not unity, unlike in continuous time processes with instantaneous resetting, but above 1 and depends on the minimal MFPT. The approach is general and applicable to the study of different discrete-time ergodic Markov processes such as Lévy flights, where the long-range dynamics is introduced in terms of the fractional Laplacian of the graph. We apply these results to the study of optimal transport on rings and Cayley trees.
Selecting an analytical model for describing the viscosity of an oil-water emulsion in the Aspen HYSYS program
Authors: Drozdov A S , Leontev S A 
Published: May 2022

Abstract
When designing technological installations for the preparation of downhole products, it is necessary to know the dynamic viscosity of the oil-water emulsion. It is not always possible to experimentally determine the viscosity and physico-chemical parameters of the oil-water emulsion. In this regard, the formulas used in the Aspen Hysys complex for determining the dynamic viscosity at different temperatures were analyzed. When analyzing the applicability of the analytical dependences, the calculated data were compared with the experimental data obtained by physical modeling of the viscosity of the water-oil emulsion of the Chayandinskoye field. The study was conducted in two stages. The first stage consisted of constructing models of the viscosity of the oil-water emulsion for all dependencies and comparing them with experimental data. This is done to test analytical assumptions and select the most reliable models. The models were constructed for a single temperature T=20 °C. The second stage consists of predicting the viscosity of the emulsion over the entire studied temperature range from -10 to 60 °C and water cut from 0.5 to 95% by weight, followed by verifying the reliability of the results of analytical calculations, as well as identifying existing shortcomings. An alternative formula is proposed, which does not contain empirical constants, describes the entire possible range of water cut, and has a relative forecast error of about 30%. In the future, it is planned to test the formula on water-oil emulsions with oils having similar properties (density, viscosity, amount of paraffins).
Reassessment of the potential of oil reserves in thin-layered “hazel grouse” type reservoirs
Authors: Agishev E R , Andreev V E , Kuleshova L S , Mukhametshin V V , Mingulov Sh G , Akhmetshina D I 
Published: May 2022

Abstract
The article describes an integrated approach to the development of solutions for the effective involvement of oil in the development of a thin-layered “hazel grouse” type reservoir. The principles of justification based on facies, geological-hydrodynamic and geomechanical modeling are analyzed. In the course of the work, new core data and a petrophysical model were obtained, which made it possible to substantiate the TRIZ status of the object. A conceptual geological model was built and an assessment of geological reserves was carried out to determine the priority zones for putting wells into operation.
Justification for proppant concentration choice during hydraulic fracturing
Authors: Kochetkov A V , Fattakhov I G , Kuleshova L S , Stepanova R R , Safiullina A R 
Published: May 2022

Abstract
The article presents a mathematical model of linear and nonlinear increase in proppant concentration during hydraulic fracturing. For the first time, an analytical solution using direct calculation for determining the parameters of the main hydraulic fracturing stages including the transition concentrations for given masses of proppant of various types is presented. It is shown that the use of a mathematical model in the development of a processing plan provides the correct distribution of the proppant mass by fractions, which facilitates the introduction of information and analytical systems and transferring data directly from the operating program to the database. The spreadsheet forms used in the production have been elaborated, which enables to apply the mathematical model of the operating program at each hydraulic fracturing without additional labor costs. The obtained mathematical model can be applied to improve the software used in the design, modeling and engineering support of hydraulic fracturing.
Development of a mathematical model for the formation of organic deposits based on research on their formation
Authors: Kozlov A V , Vyatkin K A , Ilushin P U 
Published: May 2022

Abstract
The processes of production and transportation of reservoir fluids are often complicated by various phenomena, among which one can distinguish the formation of organic deposits on the walls of the production tubing or linear oil pipeline. The fundamental problem in the field of oil production is the modeling of the processes of formation of these deposits, for which many models and equations have been developed. Their common disadvantage is high complexity and the need to use a complex mathematical apparatus. This work presents an equation based on laboratory studies and allowing one to model the processes of paraffin formation depending on the temperature gradient and water cut. This model shows high reliability in comparison with the classical Matzein model.
Search of chalcopyrite materials based on hybrid density functional theory calculation
Authors: Park Kanghyeon , Jeong Byeong-Hyeon , Park Ji-Sang 
Published: May 2022

Abstract
We computationally screened materials for photovoltaic applications based on hybrid density functional theory by assuming the chalcopyrite structure. Out of 96 materials, 14 materials were calculated to have a direct band gap between 0.6 eV and 2.0 eV, potentially applicable for photovoltaic applications. Materials with transition metals like Cr and Co were metallic, and those with Fe, Sc, and Y had indirect band gaps. Synthesis of 13 materials in experiments was reported, and the remaining one was thermodynamically unstable. Ag-containing compounds have lower stacking fault energy than Cu-containing compounds.
Instabilities in magnetized inhomogeneous dusty plasmas with the effect of recombination
Authors: Pachauri Shachi , Jyoti  , Misra Kamakhya Prakash 
Published: May 2022

Abstract
An analytical formalism to understand the impact of various parameters on evolving instabilities in inhomogeneous collisional dusty plasmas is presented here under the effect of recombination. The basic fluid dynamics for electrons and singly charged cold ions is carried out including recombination and collision at constant rate at the surface of dust particles. Dust particles are considered to be static with unperturbed density. Normal mode analysis method has been used along with linear approximation to get perturbed densities (n

i1, n

e1) which are used along with quasi-neutrality condition to get perturbed potential

(

φ

1

)
,

using Poisson’s equation to obtain dispersion relation. While other authors have detected instabilities in unmagnetized plasmas, here this method has been successfully realized in presence of static magnetic field at various propagation angle and allowed the straightforward calculation of growth rates of observed instability. An extensive study of the unstable modes has been done which are well discriminated and plotted with respect to different plasma parameters like dust charge, dust density, propagation angle, magnetic field, electrostatic potential along with plasma oscillation wavelength to Debye wavelength ratio. We have observed in the said model that the presence of dust particles and propagation angle of applied magnetic field are affecting significantly the growth rate of instability as compared to magnetic field and recombination.
A random matrix theory approach to damping in deep learning
Authors: Granziol Diego , Baskerville Nicholas 
Published: May 2022

Abstract
We conjecture that the inherent difference in generalisation between adaptive and non-adaptive gradient methods in deep learning stems from the increased estimation noise in the flattest directions of the true loss surface. We demonstrate that typical schedules used for adaptive methods (with low numerical stability or damping constants) serve to bias relative movement towards flat directions relative to sharp directions, effectively amplifying the noise-to-signal ratio and harming generalisation. We further demonstrate that the numerical damping constant used in these methods can be decomposed into a learning rate reduction and linear shrinkage of the estimated curvature matrix. We then demonstrate significant generalisation improvements by increasing the shrinkage coefficient, closing the generalisation gap entirely in both logistic regression and several deep neural network experiments. Extending this line further, we develop a novel random matrix theory based damping learner for second order optimisers inspired by linear shrinkage estimation. We experimentally demonstrate our learner to be very insensitive to the initialised value and to allow for extremely fast convergence in conjunction with continued stable training and competitive generalisation. We also find that our derived method works well with adaptive gradient methods such as Adam.
Non-linear modelling reveals a predominant moisture limit on juniper growth across the southern Tibetan Plateau
Authors: Jia Hengfeng , Fang Ouya , Lyu Lixin 
Published: May 2022

Abstract

Background and Aims
Tree growth in plateau forests is critically limited by harsh climatic conditions. Many mathematical statistical methods have been used to identify the relationships between tree growth and climatic factors, but there is still uncertainty regarding the relative importance of these factors across different regions. We tested major climatic limits at 30 sites to provide insights into the main climatic limits for juniper trees (Juniperus tibetica Kom.) across the southern Tibetan Plateau.

Methods
We analysed the linear and non-linear relationships between tree growth and climatic factors using Pearson correlation statistics and a process-based forward Vaganov–Shashkin-Lite (VS-Lite) model, respectively. These relationships were used to identify the strength of the influence of different climatic factors throughout the species’ growing season and to identify the main climatic factors limiting tree growth.

Key Results
Growth of juniper trees began in April and ended in October in the study area. The radial growth of juniper trees was limited by soil moisture throughout the summer (June–August) of the current year at 24 sampling sites and was limited by temperature at the other six sites on the southern Tibetan Plateau.

Conclusions
Soil moisture limited juniper growth at the majority of sites. Temperature in the current summer limited the growth of juniper trees at a few sampling sites in the western part of the study area. Local climate conditions may contribute to different limiting factors in the growth response of trees on the southern Tibetan Plateau. These findings may contribute to our understanding of divergent forest dynamics and to sustainable forest management under future climate scenarios.
Photizo: an open-source library for cross-sample analysis of FTIR spectroscopy data
Authors: Grant-Peters Melissa , Rich-Griffin Charlotte , Grant-Peters Jonathan E , Cinque Gianfelice , Dendrou Calliope A 
Published: May 2022

AbstractMotivationWith continually improved instrumentation, Fourier transform infrared (FTIR) microspectroscopy can now be used to capture thousands of high-resolution spectra for chemical characterization of a sample. The spatially resolved nature of this method lends itself well to histological profiling of complex biological specimens. However, current software can make joint analysis of multiple samples challenging and, for large datasets, computationally infeasible.ResultsTo overcome these limitations, we have developed Photizo—an open-source Python library enabling high-throughput spectral data pre-processing, visualization and downstream analysis, including principal component analysis, clustering, macromolecular quantification and mapping. Photizo can be used for analysis of data without a spatial component, as well as spatially resolved data, obtained e.g. by scanning mode IR microspectroscopy and IR imaging by focal plane array detector.Availability and implementationThe code underlying this article is available at https://github.com/DendrouLab/Photizo with access to example data available at https://zenodo.org/record/6417982#.Yk2O9TfMI6A.
Regression of exchangeable relational arrays
Authors: Marrs F W , Fosdick B K , Mccormick T H 
Published: May 2022

Summary
Relational arrays represent measures of association between pairs of actors, often in varied contexts or over time. Trade flows between countries, financial transactions between individuals, contact frequencies between school children in classrooms and dynamic protein-protein interactions are all examples of relational arrays. Elements of a relational array are often modelled as a linear function of observable covariates. Uncertainty estimates for regression coefficient estimators, and ideally the coefficient estimators themselves, must account for dependence between elements of the array, e.g., relations involving the same actor. Existing estimators of standard errors that recognize such relational dependence rely on estimating extremely complex, heterogeneous structure across actors. This paper develops a new class of parsimonious coefficient and standard error estimators for regressions of relational arrays. We leverage an exchangeability assumption to derive standard error estimators that pool information across actors, and are substantially more accurate than existing estimators in a variety of settings. This exchangeability assumption is pervasive in network and array models in the statistics literature, but not previously considered when adjusting for dependence in a regression setting with relational data. We demonstrate improvements in inference theoretically, via a simulation study, and by analysis of a dataset involving international trade.
Thromboprophylaxis Use in Paediatric Inflammatory Bowel Disease: An International RAND Appropriateness Panel
Authors: Torrente Franco , Meade Susanna , Benchimol Eric I , de Ridder Lissy , Croft Nicholas M , Kammermeier Jochen , Mack David R , Klomberg Renz C W , Turner Dan , Wilson David C , Martín-de-Carpi Javier , Bronsky Jiri , Amil Dias Jorge , Walker Gregor , van Ommen C Heleen , Powar Michael P , Burgess Natasha , Irving Peter M , Samaan Mark A , Hansen Richard 
Published: May 2022

Abstract

Background and Aims
Thromboprophylaxis use in paediatric inflammatory bowel disease [IBD] is inconsistent. Current guidelines only support treating children with acute severe colitis with risk factors. We convened an international RAND panel to explore thromboprophylaxis in paediatric IBD inpatients in the context of new evidence.

Methods
We convened a geographically diverse 14-person panel of paediatric gastroenterologists alongside supporting experts. An online survey was sent before an online meeting. Panellists were asked to rate the appropriateness of thromboprophylaxis in hospitalised paediatric IBD patients via 27 scenarios of varying ages, gender, and phenotype, with and without thrombotic risk factors. Anonymised results were presented at the meeting. A second modified survey was distributed to all panellists present at the meeting. Results from the second survey constitute the RAND panel results. The validated RAND disagreement index defined disagreement when ≥ 1.

Results
The combined outcome of thromboprophylaxis being considered appropriate until discharge and inappropriate to withhold was seen in 20 of 27 scenarios, including: all patients with new-onset acute severe colitis; all flares of known ulcerative colitis, irrespective of risk factors except in pre-pubescent patients with limited disease and no risk factors; and all Crohn’s patients with risk factors. Disagreement was seen in five scenarios regarding Crohn’s without risk factors, where outcomes were already uncertain.

Conclusions
RAND panels are an established method to assess expert opinion in areas of limited evidence. This work therefore constitutes neither a guideline nor a consensus; however, the findings suggest a need to re-evaluate the role of thromboprophylaxis in future guidelines.
Validation of the Soleris®Enterobacteriaceae Method for Detection of Enterobacteriaceae in Dried Cannabis Flower: AOAC Performance Tested MethodSM 121901
Authors: Le Quynh-Nhi , Mozola Mark , Tudor Alexandra , Horine Leo , Roman Brooke , Montei Carolyn , Zhang Lei , Biswas Preetha , Donofrio Robert 
Published: May 2022

Abstract:

Background
The Soleris®Enterobacteriaceae vial is a growth-based, automated method for detection of bacteria of the family Enterobacteriaceae in foods and other sample types including nutraceuticals and cosmetics. The Soleris method is used in a “dilute-to-specification” or threshold manner, in which a result is scored as positive or negative around a predetermined cutoff (in CFU/g) established by the dilution and volume of sample homogenate tested. The Soleris method was granted AOAC Performance Tested MethodSM (PTM) status for select foods after successful completion of a validation study (PTM 121901).

Objective
The objective of this study was to validate the method for the detection of Enterobacteriaceae in dried cannabis flower [&gt;0.3% delta-9-tetrahydrocannabinol (THC)].

Methods
The matrix study included comparison of Soleris method presumptive results to confirmation from the Soleris vials, and comparison of the Soleris confirmed results to those of the ISO 21528-2:2017 colony count method. Test materials at four different levels of contamination ranging from 7.8 to 3500 CFU/g were tested at three dilutions, corresponding to test thresholds.

Results
Probability of detection analysis at P &lt; 0.05 showed there were no significant differences between Soleris presumptive and confirmed results, and no significant differences between Soleris confirmed and ISO 21528-2:2017 results.

Conclusion
The results provided evidence that the Soleris Enterobacteriaceae test is an accurate method for detection of Enterobacteriaceae in dried cannabis flower.

Highlights
The Soleris Enterobacteriaceae method provides cannabis industry QC personnel with an effective method for analysis of dried cannabis flower and produces results in 20–24 h.
Uranotaenia (Pseudoficalbia) bhutanensis (Diptera: Culicidae), A New Species From Bhutan
Authors: Somboon Pradya , Namgay Rinzin , Harbach Ralph E 
Published: May 2022

Abstract
A new species of the subgenus Pseudoficalbia of the genus Uranotaenia is described from larvae found in a hole in a log at high altitude in montane forest in the Mongar District of Bhutan. Based on morphology, the larvae are sufficiently distinct from other species of the subgenus to be described and formally named here as Uranotaenia bhutanensis Somboon, Namgay & Harbach, n. sp. The species is a member of the Bimaculata Series. The chaetotaxy of the fourth-instar larva is provided.
Bone Marrow-Derived Mesenchymal Stem Cell-Derived Exosomes Containing Gli1 Alleviate Microglial Activation and Neuronal Apoptosis In Vitro and in a Mouse Parkinson Disease Model by Direct Inhibition of Sp1 Signaling
Authors: Cai Yang , Zhang Ming-Ming , Wang Ming , Jiang Zhuo-Hang , Tan Zhi-Gang 
Published: May 2022

Abstract
This study investigated possible therapeutic effect mechanisms of exosomes from bone marrow-derived mesenchymal stem cells (BMSC) in neuronal and microglial cells and in a Parkinson disease (PD) model. Neuronal SH-SY5Y cells and microglial HMC3 cells were subjected to 1-methyl-4-phenylpyridinium (MPP+) or LPS, respectively. The mRNA and protein expression was assessed using qRT-PCR, Western blotting, and enzyme-linked immunosorbent assay. Cell viability and apoptosis of SH-SY5Y cells were examined using the MTT assay and flow cytometry. Chromatin immunoprecipitation assays were performed to assess the binding relationship between glioma-associated oncogene homolog 1 (Gli1) and the Sp1 transcription factor promoter. BMSC-derived exosomes promoted cell proliferation and inhibited apoptosis in MPP+-treated SH-SY5Y cells and suppressed inflammatory markers in LPS-treated HMC3 cells. Sp1 knockdown decreased SH-SY5Y cell damage and HMC3 immune activation. Gli1 carried by BMSC exosomes directly bound with Sp1 to inhibit Sp1-mediated LRRK2 activation whereas exosomes secreted by Gli1-knockdown in BMSC did not. In a PD mouse model induced with MPTP, BMSC exosomes decreased neuron loss injury and the inflammatory response by inhibiting Sp1 signaling. Thus, BMSC-derived exosomal Gli1 alleviates inflammatory damage and neuronal apoptosis by inhibiting Sp1 in vitro and in vivo. These findings provide the basis for the potential clinical use of BMSC-derived exosomes in PD.
Visual Estimation Accuracy of Tree Part Diameter and Fall Distance
Authors: Klein Ryan W , McLean Drew C , Koeser Andrew K , Hauer Richard J , Miesbauer Jason W , Salisbury Allyson B 
Published: May 2022

Abstract
When professionals assess tree risk, they must consider the potential consequences associated with a branch or whole tree striking a person, vehicle, or structure. This process requires an assessor to determine the diameter and fall distance of a tree part and then gauge the likely damage to a target if failure occurred. The ability to accurately estimate diameter and fall distances is important, as direct measurements are not always possible. In this study, we examined whether differences exist between visual estimations and direction measurements of tree part diameters and fall distances among 106 arborists of differing experience levels. Our findings suggest arborists’ estimations were reasonably accurate in comparison to direct measurements. International Society of Arboriculture Certified Arborists and experienced arborists were more accurate in diameter estimations than arborists lacking assessment experience. In contrast, nonexperienced arborists were closer in their fall distance estimations than arborists with risk assessment experience.