bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anisotropic deformations in a class of projectively-invariant metric-affine theories of gravity
Authors: Jiménez Jose Beltrán , de Andrés Daniel , Delhom Adrià 
Published: September 2020

Abstract
Among the general class of metric-affine theories of gravity, there is a special class conformed by those endowed with a projective symmetry. Perhaps the simplest manner to realise this symmetry is by constructing the action in terms of the symmetric part of the Ricci tensor. In these theories, the connection can be solved algebraically in terms of a metric that relates to the spacetime metric by means of the so-called deformation matrix that is given in terms of the matter fields. In most phenomenological applications, this deformation matrix is assumed to inherit the symmetries of the matter sector so that in the presence of an isotropic energy–momentum tensor, it respects isotropy. In this work we discuss this condition and, in particular, we show how the deformation matrix can be anisotropic even in the presence of isotropic sources due to the non-linear nature of the equations. Remarkably, we find that Eddington-inspired-Born–Infeld (EiBI) theories do not admit anisotropic deformations, but more general theories do. However, we find that the anisotropic branches of solutions are generally prone to a pathological physical behaviour.
Junction conditions in Palatini f(R) gravity
Authors: Olmo Gonzalo J , Rubiera-Garcia Diego 
Published: September 2020

Abstract
We work out the junction conditions for f(R) gravity formulated in metric-affine (Palatini) spaces using a tensor distributional approach. These conditions are needed for building consistent models of gravitating bodies with an interior and exterior regions matched at some hypersurface. Some of these conditions depart from the standard Darmois-Israel ones of general relativity and from their metric f(R) counterparts. In particular, we find that the trace of the stress–energy momentum tensor in the bulk must be continuous across the matching hypersurface, though its normal derivative need not to. We illustrate the relevance of these conditions by considering the properties of stellar surfaces in polytropic models, showing that the range of equations of state with potentially pathological effects is shifted beyond the domain of physical interest. This confirms, in particular, that neutron stars and white dwarfs can be safely modelled within the Palatini f(R) framework.
Gauge, canonical and Galilean transformations and the non-uniqueness of Lagrange functions
Authors: Wei L F 
Published: September 2020

Abstract
The non-uniqueness of Lagrange functions is a standard topic in classical mechanics. However, it is still troublesome in undergraduate and graduate teaching. In this paper, we show that this non-uniqueness is equivalent to gauge freedom, and thus the gauge, canonical, and Galilean transformations are equivalent. In this sense, we also discuss how to solve the problem of selecting one out of many gauge-equivalent Hamiltonians to represent energy.
Inexact Newton-type methods based on Lanczos orthonormal method and application for full waveform inversion
Authors: He Qinglong , Wang Yanfei 
Published: September 2020

Abstract
The second-order derivative information plays an important role for large-scale full waveform inversion problems. However, exploiting this information requires massive computations and memory requirements. In this study, we develop two inexact Newton methods based on the Lanczos tridiagonalization process to consider the second-order derivative information. Several techniques are developed to improve the computational performance for our proposed methods. We present an effective stopping condition and implement a nonmonotone line search method. A method based on the adjoint-state method is used to efficiently compute Hessian-vector products. In addition, a diagonal preconditioner using the pseudo-Hessian matrix is employed to accelerate solving the Newton equation. Furthermore, we combine these two inexact Newton methods to improve the computational efficiency and the resolution. 2D and 3D experiments are given to demonstrate the convergence and effectiveness of our proposed methods. Numerical results indicate that, compared with the inversion methods based on the first-order derivative, both methods have good computational efficiency. Meanwhile, the method based on MINRES solver performs better than the method with Lanczos_CG due to its ability of utilizing the negative eigenvalue information when solving strongly nonlinear and ill-posed problems.
Shock wave propagation in long laboratory sparks under negative switching impulses
Authors: Liao Yuqin , Mahardika Nanang , Zhao Xiangen , Lee Juhyeong , He Junjia 
Published: September 2020

Abstract
A series of 1.27 m air gap discharge tests under negative switching impulses were carried out to characterize shock wave expansion behavior along leader channels. A high-speed Schlieren system was used to identify shock wave propagation characteristics near the high-voltage electrode. According to the Schlieren images, three distinct types of shock waves were recognized during the leader propagation and after the air gap breakdown: (1) spherical shock wave (SSW), (2) cylindrical shock wave (CSW), and (3) bow shock wave (BSW). To the best of our knowledge, it is the first time to recognize SSWs at the point where the space leader meets the main channel and BSWs along the leader branch after the main leader bridges the air gap. According to the proposed velocity calculation method, the propagation velocity of SSW and CSW was calculated as a function of the shock radius, as well as the shock wave head of BSW. Moreover, a transient magnetohydrodynamics model was developed to predict shock wave front propagation characteristics of both straight and bending channels after breakdown. The predicted shock wave propagation velocity and shock radius showed good agreement with Schlieren images.
Two-loop cutoff renormalization of 4-D Yang–Mills effective action
Authors: Ivanov A V , Kharuk N V 
Published: September 2020

Abstract
In the paper we study the Yang–Mills effective action in the four-dimensional spacetime by using background field formalism. We give an explicit way of cutoff regularization procedure, then do a two-loop renormalization and calculate a second β-function coefficient. We also show that the two-loop singularity contains only logarithmic part in the first degree. At the same time additional properties of a Green function regular part are obtained.
Ultrafast optical spectroscopy of semiconducting and plasmonic nanostructures and their hybrids
Authors: Catone Daniele , Di Mario Lorenzo , Martelli Faustino , O’Keeffe Patrick , Paladini Alessandra , Stefano Pelli Cresi Jacopo , Sivan Aswathi K , Tian Lin , Toschi Francesco , Turchini Stefano 
Published: September 2020

Abstract
The knowledge of the carrier dynamics in nanostructures is of fundamental importance for the development of (opto)electronic devices. This is true for semiconducting nanostructures as well as for plasmonic nanoparticles (NPs). Indeed, improvement of photocatalytic efficiencies by combining semiconductor and plasmonic nanostructures is one of the reasons why their ultrafast dynamics are intensively studied. In this work, we will review our activity on ultrafast spectroscopy in nanostructures carried out in the recently established EuroFEL Support Laboratory. We have investigated the dynamical plasmonic responses of metal NPs both in solution and in 2D and 3D arrays on surfaces, with particular attention being paid to the effects of the NP shape and to the conversion of absorbed light into heat on a nano-localized scale. We will summarize the results obtained on the carrier dynamics in nanostructured perovskites with emphasis on the hot-carrier dynamics and in semiconductor nanosystems such as ZnSe and Si nanowires, with particular attention to the band-gap bleaching dynamics. Subsequently, the study of semiconductor-metal NP hybrids, such as CeO2-Ag NPs, ZnSe-Ag NPs and ZnSe-Au NPs, allows the discussion of interaction mechanisms such as charge carrier transfer and Förster interaction. Finally, we assess an alternative method for the sensitization of wide band gap semiconductors to visible light by discussing the relationship between the carrier dynamics of TiO2 NPs and V-doped TiO2 NPs and their catalytic properties.
Validation of a pseudo-3D phantom for radiobiological treatment plan verifications
Authors: Kartini D A , Sokol O , Wiedemann J , Tinganelli W , Witt M , Camazzola G , Krämer M , Talabnin C , Kobdaj C , Fuss M C 
Published: September 2020

Abstract
Performing realistic and reliable in vitro biological dose verification with good resolution for a complex treatment plan remains a challenge in particle beam therapy. Here, a new 3D bio-phantom consisting of 96-well plates containing cells embedded into Matrigel matrix was investigated as an alternative tool for biological dose verification. Feasibility tests include cell growth in the Matrigel as well as film dosimetric experiments that rule out the appearance of field inhomogeneities due to the presence of the well plate irregular structure. The response of CHO-K1 cells in Matrigel to radiation was studied by obtaining survival curves following x-ray and monoenergetic 12C ion irradiation, which showed increased radioresistance of 3D cell cultures in Matrigel as compared to a monolayer. Finally, as a proof of concept, a 12C treatment plan was optimized using in-house treatment planning system TRiP98 for uniform cell survival in a rectangular volume and employed to irradiate the 3D phantom. Cell survival distribution in the Matrigel-based phantom was analyzed and compared to cell survival in a reference setup using cell monolayers. Results of both methods were in good agreement and followed the TRiP98 calculation. Therefore, we conclude that this 3D bio-phantom can be a suitable, accurate alternative tool for verifying the biological effect calculated by treatment planning systems, which could be applied to test novel treatment planning approaches involving multiple fields, multiple ion modalities, complex geometries, or unconventional optimization strategies.
IPEM Topical Report: An evidence and risk assessment based analysis of the efficacy of quality assurance tests on fluoroscopy units—part II; image quality
Authors: Shaw Dan , Worrall Mark , Baker Chris , Charnock Paul , Fazakerley Jason , Honey Ian , Iball Gareth , Koutalonis Manthos , Price Mandy , Renaud Caroline , Rose Amy , Wood Tim 
Published: September 2020

Abstract
This work aims to assess the efficacy of x-ray quality assurance tests undertaken on fluoroscopy units in the UK. Information was gathered on the results of image quality tests recommended by the reports of the Institute of Physics and Engineering in Medicine, and those additionally undertaken by medical physics departments. The assessment of efficacy considers the frequency with which a test result breaches the remedial level or other relevant threshold where applicable. The third quartile of those results exceeding the remedial level or threshold is used to estimate the severity of such a breach in terms of potential impact on patient dose and image quality. A risk assessment approach is then used to recommend to what degree, if any, the test should be included in an on-going test regimen.
Data was analysed from 469 testing sessions to 337 unique fluoroscopy units throughout the UK. Across all tests, the rate with which the remedial level was exceeded varied from 0–10.6%, with severity ranging from little or none to major degradation to image quality or significant increase on population dose. Where possible, the data has also been used to produce representative ranges for the results of image quality tests. These could be useful as an up to date comparator for those sites considering the purchase of or commissioning new equipment.
Overall the results indicate a wide range for the efficacy of those tests undertaken at present; this can be used to review local test protocols and to inform future changes to national guidance in the UK. The results also highlight some tests where measurement technique varies significantly throughout the UK, making any valid comparison difficult. This may indicate a need for further guidance on how best to undertake these tests.
Dynamics of guided post-acceleration of protons in a laser-driven travelling-field accelerator
Authors: Hadjisolomou P , Ahmed H , Prasad R , Cerchez M , Brauckmann S , Aurand B , Schroer A M , Swantusch M , Willi O , Borghesi M , Kar S 
Published: September 2020

Abstract
By directing the laser-driven electromagnetic pulses along a helical path, one can achieve a travelling-field accelerator arrangement for simultaneous beam shaping and re-acceleration of laser-accelerated protons. The dynamics of guided acceleration of the transiting protons was studied by varying the length of the helical coil. Experimental data shows that the protons co-moving with the field region exhibit stronger focussing while increasing the coil length, with an increase of kinetic energy due to simultaneous post-acceleration. The net energy gain for a coil of constant pitch however saturates eventually when the post-accelerated protons overtakes the accelerating field region in due course. 3D particle tracing simulation underpins the dynamics of beam transport inside the coil, which highlights the requirement for a variable pitch coil geometry in order to sustain the post-acceleration over an extended coil.
Retraction: Efficiency of Mining Algorithms in Academic Indicators (Journal of Physics: Conference Series
1432 012030)
Authors: Viloria Amelec , Palma Hugo Hernández , Núñez William Niebles , Gaitán Mercedes , Lezama Bonerge Pineda 
Published: September 2020

Published 15 September 2020
This article, and others within this volume, has been retracted by IOP Publishing following clear evidence of plagiarism and citation manipulation.
This work was originally published in Spanish (1) and has been translated and published without permission or acknowledgement to the original authors. IOP Publishing Limited has discovered other papers within this volume that have been subjected to the same treatment. This is scientific misconduct.
Misconduct investigations are ongoing at the author’s institutions. IOP Publishing Limited will update this notice if required once those investigations have concluded. To date, there is no evidence to suggest anyone other than Amelec Viloria / Jesus Silva was directly culpable for the actions that led to retraction.
IOP Publishing Limited request any citations to this article be redirected to the original work (1).
Anyone with any information regarding these papers is requested to contact jpconf@ioppublishing.org
Retraction: Neural Networks for Tea Leaf Classification (Journal of Physics: Conference Series
1432 012075)
Authors: Silva Jesús , Palma Hugo Hernández , Núñez William Niebles , Ruiz-Lazaro Alex , Varela Noel 
Published: September 2020

Published 15 September 2020
This article, and others within this volume, has been retracted by IOP Publishing following clear evidence of plagiarism and citation manipulation.
This work was originally published in Spanish (1) and has been translated and published without permission or acknowledgement to the original authors. IOP Publishing Limited has discovered other papers within this volume that have been subjected to the same treatment. This is scientific misconduct.
Misconduct investigations are ongoing at the author’s institutions. IOP Publishing Limited will update this notice if required once those investigations have concluded. To date, there is no evidence to suggest anyone other than Amelec Viloria / Jesus Silva was directly culpable for the actions that led to retraction.
IOP Publishing Limited request any citations to this article be redirected to the original work (1).
Anyone with any information regarding these papers is requested to contact conferenceseries@ioppublishing.org.
Retraction: Data Mining Applied in School Dropout Prediction (Journal of Physics: Conference Series
1432 012092)
Authors: Viloria Amelec , Guliany Jesús García , Núñez William Niebles , Palma Hugo Hernández , Núñez Leonardo Niebles 
Published: September 2020

Published 15 September 2020
This article, and others within this volume, has been retracted by IOP Publishing following clear evidence of plagiarism and citation manipulation.
This work was originally published in Spanish (1) and has been translated and published without permission or acknowledgement to the original authors. IOP Publishing Limited has discovered other papers within this volume that have been subjected to the same treatment. This is scientific misconduct.
Misconduct investigations are ongoing at the author’s institutions. IOP Publishing Limited will update this notice if required once those investigations have concluded. To date, there is no evidence to suggest anyone other than Amelec Viloria / Jesus Silva was directly culpable for the actions that led to retraction.
IOP Publishing Limited request any citations to this article be redirected to the original work (1).
Anyone with any information regarding these papers is requested to contact conferenceseries@ioppublishing.org.
Retraction: Parallel Algorithm for Reduction of Data Processing Time in Big Data (Journal of Physics: Conference Series
1432 012095)
Authors: Silva Jesús , Palma Hugo Hernández , Núñez William Niebles , Ovallos-Gazabon David , Varela Noel 
Published: September 2020

Published 15 September 2020
This article, and others within this volume, has been retracted by IOP Publishing following clear evidence of plagiarism and citation manipulation.
This work was originally published in Spanish (1) and has been translated and published without permission or acknowledgement to the original authors. IOP Publishing Limited has discovered other papers within this volume that have been subjected to the same treatment. This is scientific misconduct.
Misconduct investigations are ongoing at the author’s institutions. IOP Publishing Limited will update this notice if required once those investigations have concluded. To date, there is no evidence to suggest anyone other than Amelec Viloria / Jesus Silva was directly culpable for the actions that led to retraction.
IOP Publishing Limited request any citations to this article be redirected to the original work (1).
Anyone with any information regarding these papers is requested to contact conferenceseries@ioppublishing.org.
Retraction: Time Series Decomposition using Automatic Learning Techniques for Predictive Models (Journal of Physics: Conference Series
1432 012096)
Authors: Silva Jesús , Palma Hugo Hernández , Núñez William Niebles , Ovallos-Gazabon David , Varela Noel 
Published: September 2020

Published 15 September 2020
This article, and others within this volume, has been retracted by IOP Publishing following clear evidence of plagiarism and citation manipulation.
This work was originally published in Spanish (1) and has been translated and published without permission or acknowledgement to the original authors. IOP Publishing Limited has discovered other papers within this volume that have been subjected to the same treatment. This is scientific misconduct.
Misconduct investigations are ongoing at the author’s institutions. IOP Publishing Limited will update this notice if required once those investigations have concluded. To date, there is no evidence to suggest anyone other than Amelec Viloria / Jesus Silva was directly culpable for the actions that led to retraction.
IOP Publishing Limited request any citations to this article be redirected to the original work (1).
Anyone with any information regarding these papers is requested to contact conferenceseries@ioppublishing.org.
Double charge exchange reactions as a probe for neutrinoless double beta decay nuclear matrix elements
Authors: Santopinto E. , Ferretti J. , García-Tecocoatzi H. , Magana Vsevolodovna R. 
Published: September 2020

Abstract
The formalism to describe heavy-ion double charge exchange (DCE) processes in the eikonal and small-momentum transfer approximations introduced in Phys. Rev. C 98, 061601(R) (2018) is briefly discussed. It is also shown that, under the previous approximations, the heavy-ion DCE cross-section can be factorized in terms of a reaction and a nuclear part. A double charge exchange effective potential is explicitly derived in the closure approximation and also for the first time the explicit form of the DCE nuclear matrix elements, that are of the form of double Gamow-Teller and double Fermi. The recent hypothesis of a linear correlation between double Gamow-Teller neutrinoless double beta decay and DCE nuclear matrix elements is confirmed thanks to the first explicit derivation of DCE nuclear matrix elements, and by means of microscopic IBM2 calculations.
Utilization of liquid smoke nanoencapsulation in fresh fish fillets as a preservation material
Authors: Swastawati F , Romadhon  
Published: September 2020

Abstract
Liquid smoke of coconut shell was process to produce nanoencapsulation using 10% of arabic gum (A), 10% of maltoodextrin (M) and mixed of 5% arabic gum + 5% of maltodextrin (AM). The products of all microencapsulation (A, M, AM) were then been analyzed in terms of : fenol content, pH, particel size, solution test, acid content, carbonyl content, and also their colour characteristic. After all, the nanoencapsulation were apllied into white snapper for 2% w/w stand for. The fish sample then evaluated in terms of their color and TVBN values. The result of total phenolic compound of nanocapsule were found about :0.72% - 0.95%, carbonyl compound :1.812% - 2.380, acid value :11.04mg/g - 22.82mg/g and pH value of :4.1 – 4.6. The bacterial count on the snapper fillets between 5,04 Log CFU/g to 5,82 Log CFU/g. The result suggested that nancapsules had spherical and wrinkle shape with an average size of nanocapsules of 28.03 nm.