bluuebunny/crossref_metadata_2025 huggingface dataset:
Shortening the immunocastration-to-slaughter interval from 3 to 2 weeks reduced carcass backfat and weight, increased sexual behaviour and carcass skin blemishes in group-housed male pigs sold at fixed age
Authors: Liu Fan , Morrison Rebecca S. , Lealiifano Amy K. , Brewster Chris J. , Henman David J. , Smits Robert J.
Published: February 2021

Context Pig producers require strategies to temporarily slow growth rate, particularly when markets impose penalties on over-weight and fat carcasses. Immunocastrated pigs usually have higher feed intakes (e.g. during the 3–5-week immunocastration-to-slaughter interval, which is commonly used in Australian pig industry), resulting in higher carcass weight and backfat thickness. Shortening the immunocastration-to-slaughter interval by delaying the second vaccination by a week may be a fine-tuned strategy to reduce carcass backfat and weight of male pigs. However, postponing the age receiving immunocastration as a method to achieve a shorter immunocastration-to-slaughter interval may increase aggressive and sexual behaviours of pigs. Aims The experiment aimed to quantify the effects of shortening the interval between the second dose of immunocastration and slaughter from 3 weeks to 2 weeks on growth performance, carcass traits, aggressive and sexual behaviours, and carcass skin blemishes in group-housed male finisher pigs slaughtered at a fixed age. Methods Pigs (n = 58 pens; 45 pigs per pen) were selected into the experiment at 16 weeks of age. Half of the pens received the second anti-GnRH vaccine (V2) as a means of immunocastration at 19 weeks (a common immunocastration age used in Australian pig industry; control group), and the remaining half of the pens received V2 at 20 weeks of age. All the pigs were slaughtered at 22 weeks of age. Growth performance was recorded between 16 and 22 weeks of age. Behavioural observation was conducted at 20 and 21 weeks of age. Carcass weight, backfat thickness and severity of skin blemishes on carcasses were recorded in the abattoir. Key results Results showed that shortening the immunocastration-to-slaughter interval from 3 to 2 weeks reduced average daily feed intake by 9%, growth rate by 8%, carcass weight by 3%, and backfat thickness by 7% (all P < 0.05), but the percentage of pigs that displayed sexual behaviour and carcasses with >25 lesions both increased (both P < 0.05). Conclusions Shortening the immunocastration-to-slaughter interval from 3 to 2 weeks by delaying V2 is an effective strategy to reduce feed intake, growth rate, carcass weight and backfat in group-housed male pigs, but at a risk of increasing carcass skin blemishes. Implications The increased sexual behaviour and carcass skin blemishes will need to be managed when using a shortened immunocastration-to-slaughter interval to temporarily reduce carcass weight and backfat.
Beyond multimorbidity: primary care and the older person with complex needs
Authors: Mann Jennifer , Thompson Fintan , Quigley Rachel , McDermott Robyn , Devine Susan , Strivens Edward
Published: February 2021

The aim of this study was to present the health and social characteristics of community-dwelling older people within the Cairns region who were identified by their GP as having complex care needs. This paper reports the subanalysis of baseline data from the Older Persons Enablement and Rehabilitation (OPEN ARCH) stepped wedge randomised controlled trial of an integrated model of care for community-dwelling older people. Data were analysed at the level of the participant and the level of the participant cluster (group of participants from the one GP). Median quality of life, as assessed by the EQ-5D, was higher for females than males (80 vs 70 respectively; P = 0.05) and for people living alone than living with family (80 vs 60 respectively; P = 0.0940). There was greater functional independence among non-Indigenous than Indigenous participants (median Functional Independence Measure scores of 122 vs 115 respectively; P = 0.0937) and the incidence rate (95% confidence intervals) of presentation to the emergency department was sevenfold higher for Indigenous than non-Indigenous participants (11.47 (5.93–20.03) vs 1.65 (0.79–3.04) per 1000 person days respectively). Finally, 61.3% of participants required support to remain living in the community and 44% accessed allied health, with podiatry the most common intervention. The findings indicate that previous hospital utilisation is not a consistent indicator of complexity. Multimorbidity, cultural context and the living and caring situation are considered as matters of complexity, yet variation exists at the participant level.
Contrasting prescription burning and wildfires in California Sierra Nevada national parks and adjacent national forests
Authors: Keeley Jon E. , Pfaff Anne , Caprio Anthony C.
Published: February 2021

History of prescription burning and wildfires in the three Sierra Nevada National Park Service (NPS) parks and adjacent US Forest Service (USFS) forests is presented. Annual prescription (Rx) burns began in 1968 in Sequoia and Kings Canyon National Parks, followed by Yosemite National Park and Lassen Volcanic National Park. During the last third of the 20th century, USFS national forests adjacent to these parks did limited Rx burns, accounting for very little area burned. However, in 2004, an aggressive annual burn program was initiated in these national forests and in the last decade, area burned by planned prescription burns, relative to area protected, was approximately comparable between these NPS and USFS lands. In 1968, the NPS prescription burning program was unique because it coupled planned Rx burns with managing many lightning-ignited fires for resource benefit. From 1968 to 2017, these natural fires managed for resource benefit averaged the same total area burned as planned Rx burns in the three national parks; thus, they have had a substantial impact on total area burned by prescription. In contrast, on USFS lands, most lightning-ignited fires have been managed for suppression, but increasing attention is being paid to managing wildfires for resource benefit.
Mechanistic transmission modeling of COVID-19 on the
Diamond Princess
cruise ship demonstrates the importance of aerosol transmission
Authors: Azimi Parham , Keshavarz Zahra , Cedeno Laurent Jose Guillermo , Stephens Brent , Allen Joseph G.
Published: February 2021

Significance

We find that airborne transmission likely accounted for >50% of disease transmission on the
Diamond Princess
cruise ship, which includes inhalation of aerosols during close contact as well as longer range. These findings underscore the importance of implementing public health measures that target the control of inhalation of aerosols in addition to ongoing measures targeting control of large-droplet and fomite transmission, not only aboard cruise ships but in other indoor environments as well. Guidance from health organizations should include a greater emphasis on controls for reducing spread by airborne transmission. Last, although our work is based on a cruise ship outbreak of COVID-19, the model approach can be applied to other indoor environments and other infectious diseases.
A unified theory for organic matter accumulation
Authors: Zakem Emily J. , Cael B. B. , Levine Naomi M.
Published: February 2021

Significance

Organic matter in the global ocean, soils, and sediments stores about five times more carbon than the atmosphere. Thus, the controls on the accumulation of organic matter are critical to global carbon cycling. However, we lack a quantitative understanding of these controls. This prevents meaningful descriptions of organic matter cycling in global climate models, which are required for understanding how changes in organic matter reservoirs provide feedbacks to past and present changes in climate. Currently, explanations for organic matter accumulation remain under debate, characterized by seemingly competing hypotheses. Here, we develop a quantitative framework for organic matter accumulation that unifies these hypotheses. The framework derives from the ecological dynamics of microorganisms, the dominant consumers of organic matter.
Cooperativity between the orthosteric and allosteric ligand binding sites of RORγt
Authors: de Vries Rens M. J. M. , Meijer Femke A. , Doveston Richard G. , Leijten-van de Gevel Iris A. , Brunsveld Luc
Published: February 2021

Significance

RORγt is a nuclear receptor associated with several diseases. Various synthetic ligands have been developed that target the canonical orthosteric or a second, allosteric pocket of RORγt. We show that orthosteric and allosteric ligands can simultaneously bind to RORγt and that their potency is positively influenced by the other ligand, a phenomenon called cooperative dual ligand binding. The mechanism behind cooperative binding in proteins is poorly understood, primarily due to the lack of structural data. We solved 12 crystal structures of RORγt, simultaneously bound to various orthosteric and allosteric ligands. In combination with molecular dynamics, we reveal a mechanism responsible for the cooperative binding behavior. Our comprehensive structural studies provide unique insights into how cooperative binding occurs in proteins.
Why it might be bad for brain cells to eat malaria parasites
Authors: Higgins Matthew K.
Published: February 2021

In this issue, Adams et al. (2021. J. Exp. Med. https://doi.org/10.1084/jem.20201266) show that red blood cells infected with strains of Plasmodium falciparum, which are commonly found in cerebral malaria patients, are specifically internalized by brain endothelial cells, perhaps contributing to the symptoms of the disease.
Interaction of Gardner solitons in plasmas: applications in the Saturn’s magnetosphere
Authors: Nawaz H , Masood W , Jahangir R , Siddiq M
Published: February 2021

Multi-soliton solutions of the Gardner equation (GE) have been obtained using the Hirota’s bilinear formalism and, to the best of our knowledge, have been studied in the context of plasmas for the first time. The results have been used to study the electrostatic waves on the ion time scale in a two-electron temperature (TET) kappa distributed plasma in the light of the data obtained from Saturn’s Magnetosphere. The most important result that has come out of the investigation of multi-soliton solution of GE is that both overtaking and head on interactions may occur owing to the simultaneous presence of quadratic and cubic nonlinearities in the GE. The plasma parameters of the system have been found to influence the spatial scale of interaction. The results of kappa distributed plasma have been compared with the Maxwellian case and the key differences with regard to the parametric regimes for the existence of ion acoustic Gardner solitons and the soliton interaction for the two cases have also been explored in detail.
Determination of 238U(n, γ) and 238U(n, f) reactions cross-section in the neutron emission spectrum of 241Am-Be source
Authors: Tohamy M , Elmaghraby Elsayed K , Comsan M N H
Published: February 2021

The neutron radiative capture and neutron fission cross-sections were measured over the neutron emission spectrum of an 241Am-Be source with an effective energy range between 1 MeV and 11 MeV using the activation method. In foils were used as a neutron flux monitor based on 115In(n, n′)115mIn reaction. The sample was a Cd-covered natural UO2 pellet. Evaluations of the yield and reaction data in the energy range from 0.1 MeV to 11 MeV had been done to validate the integral experimental results. The neutron capture cross-section, using 239Np decay, was 32.9 ± 0.9stat. mb. The fission cross-section was probed using gamma lines from 143Ce, 133I, 105Ru, 134I, 91Sr, 135I, and 92Sr. The weighted average value of the fission cross-section was 570 ± 24 mb. 143Ce, 133I, 135I, and 92Sr had the highest merit among fission products for the validation, use upon application of long-lived Am-Be neutrons in quantification for nuclear safeguard and security applications.
Perturbative approach for strong and weakly coupled time-dependent for non-Hermitian quantum systems
Authors: Fring Andreas , Tenney Rebecca
Published: February 2021

We propose a perturbative approach to determine the time-dependent Dyson map and the metric operator associated with time-dependent non-Hermitian Hamiltonians. We apply the method to a pair of explicitly time-dependent two dimensional harmonic oscillators that are weakly coupled to each other in a PT-symmetric fashion and to the strongly coupled explicitly time-dependent negative quartic anharmonic oscillator potential. We demonstrate that once the perturbative Ansatz is set up the coupled differential equations resulting order by order may be solved recursively in a constructive manner, thus bypassing the need for making any guess for the Dyson map or the metric operator. Exploring the ambiguities in the solutions of the order by order differential equations naturally leads to a whole set of inequivalent solutions for the Dyson maps and metric operators implying different physical behaviour as demonstrated for the expectation values of the time-dependent energy operator.
Quantum simulations with nuclear magnetic resonance system*
Authors: Qiu Chudan , Nie Xinfang , Lu Dawei
Published: February 2021

Thanks to the quantum simulation, more and more problems in quantum mechanics which were previously inaccessible are now open to us. Capitalizing on the state-of-the-art techniques on quantum coherent control developed in past few decades, e.g., the high-precision quantum gate manipulating, the time-reversal harnessing, the high-fidelity state preparation and tomography, the nuclear magnetic resonance (NMR) system offers a unique platform for quantum simulation of many-body physics and high-energy physics. Here, we review the recent experimental progress and discuss the prospects for quantum simulation realized on NMR systems.
Efficient self-testing system for quantum computations based on permutations*
Authors: Ma Shuquan , Zhu Changhua , Nie Min , Quan Dongxiao
Published: February 2021

Verification in quantum computations is crucial since quantum systems are extremely vulnerable to the environment. However, verifying directly the output of a quantum computation is difficult since we know that efficiently simulating a large-scale quantum computation on a classical computer is usually thought to be impossible. To overcome this difficulty, we propose a self-testing system for quantum computations, which can be used to verify if a quantum computation is performed correctly by itself. Our basic idea is using some extra ancilla qubits to test the output of the computation. We design two kinds of permutation circuits into the original quantum circuit: one is applied on the ancilla qubits whose output indicates the testing information, the other is applied on all qubits (including ancilla qubits) which is aiming to uniformly permute the positions of all qubits. We show that both permutation circuits are easy to achieve. By this way, we prove that any quantum computation has an efficient self-testing system. In the end, we also discuss the relation between our self-testing system and interactive proof systems, and show that the two systems are equivalent if the verifier is allowed to have some quantum capacity.
Taking tomographic measurements for photonic qubits 88 ns before they are created*
Authors: Hou Zhibo , Yin Qi , Zhang Chao , Zhong Han-Sen , Xiang Guo-Yong , Li Chuan-Feng , Guo Guang-Can , Pryde Geoff J. , Laing Anthony
Published: February 2021

We experimentally demonstrate that tomographic measurements can be performed for states of qubits before they are prepared. A variant of the quantum teleportation protocol is used as a channel between two instants in time, allowing measurements for polarization states of photons to be implemented 88 ns before they are created. Measurement data taken at the early time and later unscrambled according to the results of the protocol’s Bell measurements, produces density matrices with an average fidelity of 0.90±0.01 against the ideal states of photons created at the later time. Process tomography of the time reverse quantum channel finds an average process fidelity of 0.84±0.02. While our proof-of-principle implementation necessitates some post-selection, the general protocol is deterministic and requires no post-selection to sift desired states and reject a larger ensemble.
Bayesian approach to parameter estimation and model validation for nuclear fusion reactor mean-field edge turbulence modelling
Authors: De Wolf R. , Coosemans R. , Dekeyser W. , Baelmans M.
Published: February 2021

This paper presents a Bayesian approach to infer about two mean-field plasma turbulence models, a first based on the turbulent kinetic energyk⊥, and a second based onk⊥and the turbulent enstrophyζ⊥. These models contain several closure terms with unknown constants that have to be determined through fitting to reference data from turbulence simulations or experiments. In this paper, we compare two techniques to solve the Bayesian inference problem: the Laplace approximation and the adaptive Metropolis–Hastings (AMH) algorithm. Our Bayesian inference allows for parameter uncertainty quantification, identification of parameter cross-correlations and model comparison through the Bayesian evidence. Our results indicate that while a diffusivek⊥–ζ⊥scaling for the anomalous diffusion coefficient provides a better approximation to the turbulent particle flux when based on exact turbulence simulation data, at present large modelling uncertainties and parameter cross-correlations in the fullk⊥–ζ⊥model make it less performant than the more simplek⊥model. For the cases studied here, the cross-correlations can be removed by a reparameterization of thek⊥–ζ⊥model with fewer parameters. The results can form the basis for further development of the turbulence models.
Intelligent distributed module for local control of lighting and electrical outlets in a home
Authors: Andramuño J. , Mendoza E. , Núñez J. , Liger E.
Published: February 2021

This article proposes a control of lighting and electrical loads, suitable for smart homes, using embedded systems with low-cost wireless communication modules. The system is based on a distributed intelligent home automation architecture, to work autonomously or interconnect wirelessly to a larger system. It has a set of sensors that allow you to ration the use of electricity through automatic switching off the lights or electrical devices, allowing the lighting to be regulated. It has several modules that communicate to a central node wirelessly, and an interface based on a mobile application. UML and Petri Nets were used for the projection, modelling and validation of the system, its implementation was developed in C/C ++ language for 32-bit microcontrollers. Tests of the prototype showed stable behavior, fast communications and sufficient coverage for a single-family house, whose performance is higher to other similar works found in the scientific community.
Modelling preferential flow through unsaturated porous media with the Preisach model and an extended Richards Equation to capture hysteresis and relaxation behaviour
Authors: Roche W.J. , Murphy K. , Flynn D.P.
Published: February 2021

The unsaturated flow of water in soil through unstable wetting fronts has been documented in literature. These instabilities can lead to the development of finger-flow profiles, whose paths can be “remembered” by a solid matrix of soil during future infiltration even after periods of desaturation. This process has been modelled for a 1D column of soil by the Richards equation, a non-equilibrium relaxation ODE, and Preisach hysteresis, all of which are required for finger flow. In this paper a comparison is made to similar work that use Parlange’s model of hysteresis and show that similar results are achieved by instead including the Preisach model. In addition, the model allows for the strength of hysteresis to be changed by a single parameter thus allowing the potential of parameter fitting of data in the future.
Mathematical modeling the process of wire surfacing by the smoothed particle hydrodynamics method
Authors: Davlyatshin R P , Gerasimov R M , Bayandin Y V , Permyakov G L , Trushnikov D N
Published: February 2021

We discuss issues the process of layer-by-layer synthesis of metal products by wire surfacing. A mathematical model of the process has been developed and implemented. The model allows one to calculate the volumetric distributions of temperatures, melt flow rates, pressures, components of heat fluxes density, the shape and dimensions of the molten bath, the shape of the free surface of the molten metal, the shape and dimensions of the weld bead. For this purpose, the main physical processes that affect the formation of the metal product were considered, namely: melting and crystallization of the metal, surface tension, the Marangoni effect and the heat source features. The smoothed particle method was used to implement this model. A number of numerical experiments were carried out using the developed model. Firstly, the model parameters for steel and titanium were identified and verified. After that, calculations were carried out to verify the model itself using the obtained roller geometry. The numerical solution for the deposition of one layer was compared with the full-scale experiment. The error was no more than 5% in any direction. Thus, the efficiency and correctness of the constructed model is shown.
Simulation of magnetic particle capture in the breast
Authors: Camargo Luz Helena , Pacheco Jennifer , Rodriguez Diego Julián
Published: February 2021

New strategies, such as magnetic guidance of medicines, are used in cancer treatment. This work determined the topological characteristics of blood vessels in the breast with cancer. To remove the topology of the blood vessels mammogram imaging of cancer patients, image preprocessing was performed using conventional methods (Canny, Prewitt, and Sobel), with neural networks, and with light correction techniques, a 3D model was generated with finite element software to simulate velocity and blood flow, 700 nanoparticles of Magnetite were included, with a magnet of Neodymiun and the number of nanoparticles reaching the tumor was evaluated. The best results were obtained with the light correction method that improved the definition of blood vessels with the topology obtained and more particles were found to reach the magnetic field tumor compared when it is absent.
Application of induction heating in the FDM/FFF 3D manufacturing
Authors: Oskolkov A A , Trushnikov D N , Bezukladnikov I I
Published: February 2021

This article addresses the problem of induction heating in its application to the FDM/FFF 3D manufacturing. One of the major problems of the FDM/FFF is the instability of layer-to-layer adhesion quality, and on the larger scale - maintaining the homogeneity of material inside the whole printed object. Approach for mitigating and/or resolving of those problems, based on the fast and reliable control of the extruded material temperature during the printing process was proposed. Such approach uses specially created testbed system, consists of the ultra-low weight induction heated nozzle and fast temperature controller. This equipment enables rapid heating and cooling of the nozzle at low input power. On the contrary, using of the nozzle with the minimal thermal mass poses the problems of maintaining even heat distribution on the nozzle surface, and therefore inside the heated material. Multiphysics FEM model for the electromagnetic and thermal problem for the proposed nozzle and inductor configuration was formulated, and numerically solved using COMSOL 5.2a. Parametric optimization of the inductor form and heating signal frequency was conducted. Series of the experiments with the optimized inductor construction were made using the proposed testbed, showing significant increase of the heating speed and uniform heat distribution on the nozzle surface, and therefore in the final printed object quality. Experimental data for the all stages of conducted research is provided.
Reliability-centered maintenance and cost optimization for offshore oil and gas components
Authors: Nithin A H , Sriramula S , Ebinum T
Published: February 2021

Reliability-Centered Maintenance (RCM) is widely used for enterprise asset management in the Oil and Gas sector. The traditional RCM process encompasses the development of equipment hierarchy, the determination of the functional failure of assets, identification of the critical failure modes and the development of suitable maintenance strategies for these failure modes through RCM logic tree analysis. However, the current industry standards and conditions call for greater strides of production availability and reliability of the assets. The aim of the paper is to deliver RCM oriented cost optimization framework for the assets through the implementation of probabilistic and statistical analysis. Probabilistic analysis of the most critical components predicts the failure over time. The mean time to failure, mean time between failure and mean time to repair parameters are determined from the failure history. The parameters of the probability distribution, for instance, the shape and scale parameters of Weibull distribution determine the failure pattern of the failure mode over time. The cost optimization modules allow the analyst to determine the optimum intervals for maintenance or replacement of the maintainable items. The integrated RCM methodology, therefore, provides quantitative and cost-effective solutions for asset maintenance and management. A case study of an equipment in the Oil and Gas sector will be presented to illustrate the optimization framework.
Elasticity index evaluation based on Le Cam divergence and kernel density estimator in PM space
Authors: Kus Vaclav , Dolejs Erik
Published: February 2021

This work focuses on the application of Preisach-Mayergoyz (PM) model applied to the evaluation of elastic properties of hysteretic material. In the first part, essential concepts are explained such as material hysteresis, probability density functions of PM space, optimization algorithm used, and phi-divergence measures applied in the PM identification process. Next, two different characterizations of PM space of hysterons based on kernel density estimators are proposed, either for one-dimensional PM space projection or for fully two-dimensional pyramid kernel. Finally, new index of elasticity is built up by means of the squared Le Cam divergence between probability density corresponding to the super-elastic distribution and the probability density found by our optimized PM identification process, respectively. This elasticity index describes ability of the material to absorb mechanical deformation, or alternatively, it gives an evidence about the certain degree of damage of the material. This proposed index of elasticity (IE) is evaluated for the case of experimental data measured on the steel dampers used for the protection against earthquakes.
Quantum Implementation for Comparing Sets of Data
Authors: Roth Yehuda
Published: February 2021

By simultaneously analyzing sets of data, we propose a quantum implementation for handling a large amount of data. Our research may be useful in big data analysis.
Gravitation in the theory of compressible oscillating ether
Authors: Magnitskii Nikolai
Published: February 2021

Previously, the basic laws and equations of electrodynamics, atomic physics, and elementary particles theory were derived from the theory and equations of compressible oscillating ether. In this work, the ethereal theory of gravitation is constructed, the similarities and differences between gravitational and electrostatic fields are explained. It is shown that in gravitation there are no attractive forces, but there are pressing forces, and that the gravitational constant is not really constant, but weakly depends on the chemical composition of interacting bodies. Gravitational interactions between bodies do not propagate from one body to another at a certain speed, and at any moment, the stationary gravitational fields exist with and around the bodies, and therefore neither gravitational waves nor gravitons exist in nature. The values of all parameters of the ether, including the density of its unperturbed state, are found
Numerical analysis of a vibro-impact system with ideal and non-ideal excitation
Authors: Hajradinovic Dzanko , Zukovic Miodrag , Kovacic Ivana
Published: February 2021

This study is concerned with modelling and analyses of a vibro-impact system consisting of a crank-slider mechanism and one oscillator attached to it, where the system can be exposed to ideal or non-ideal excitation. The impact occurs during the motion of the oscillator when it hits a base, and the excitation of the driving source is affected by this behaviour. The aim is to determine the interaction between a driving torque and the motion of the oscillator. To achieve this aim in a methodologically sound manner, both vibro-impact systems with ideal and non-ideal excitation are analysed. For these system differential equations are formed and the impact model is provided in the paper. The impact causes a strong nonlinearity in the system. The mathematical model of the vibro-impact system with ideal excitation is presented as a second order differential equation where the vibro-impact system with non-ideal excitation is given as a coupled system of nonlinear second order differential equations. Numerical simulations are carried out for the two systems and the results obtained are shown in terms of frequency response diagrams as well as in terms of time-displacement diagrams. The results found for different systems are compared mutually, and the differences between them are pointed out. Impact solutions for different regions of the excitation frequency are shown. For a specific value of the excitation frequency in the frequency response diagram where multiple solutions are found, basin of attractor diagrams are formed. Average value of the excitation frequency is used for the vibro-impact system with non-ideal excitation.
Solving an optimal control problem of the robot using the Picard’s method.
Authors: Lounis Abbes , Louadj Kahina , Aidene Mohamed
Published: February 2021

This paper presents an optimal control problem applied to the robot, the problem is to determine a command that allows to reach the final state from the initial state in record time. This problem will be solved by applying The Pontryagin’s Maximum Principle (PMP) combined with Picard’s successive approximation method and shooting method.
Mathematical model of electrical conductivity of biological tissues based on ion electrodiffusion equations
Authors: Kovalenko N V , Sovin K V , Shamankov N O , Ryabushkin O A
Published: February 2021

A method for modeling of the electrical properties of biological tissues is introduced. It is based on the division of tissue in accordance with the geometry of living cells and the solution of the Nernst-Planck electrodiffusion equation for the calculation of ion currents between individual cells.
Deformations of the Heisenberg Lie algebra
Authors: Alvarez María Alejandra
Published: February 2021

In this note we compute all deformations of the 3-dimensional Heisenberg Lie algebra ℌ3. This shows that ℌ3 deforms to almost all Lie algebras of dimension 3.
Modeling a broadband detector for an experiment that measures the speed of gravity over short distances
Authors: Frajuca C , Bortoli F S , Magalhaes N. S. , Da Silva W. C. , Souza R. C.
Published: February 2021

In order to investigate the behavior of gravitational signals while travelling through a medium an experiment was designed, aimed at measuring the speed of these signals over short distances. The experiment contains 2 sapphire devices that behave as a detector, which are suspended in vacuum and cooled down to 4.2 K. The amplitude of the detecting device is measured by an ultralow, phase-noise microwave signal that uses resonance in the whispering gallery modes. Since sapphire has a quite high mechanical Q, the detection band is expected to be small, thus reducing the detection sensitivity. A new shape for the detecting device is presented in this work, yielding a detection band of several hundred Hertz. With the aid of a Finite Element Program the normal mode frequencies of the detector are determined.
Obtaining the predicted number of cycles of femoral prosthesis manufactured with ASTM F138 and ASTM F75 aloys, applying the method of finite element.
Authors: Silva Junior Wilson Carlos Da , Pereira De Souza Caique Movio , Silva Bortoli Fabio Da , Frajuca Carlos , Souza Renato Chaves
Published: February 2021

This study aims to calculate the predictive number of cycles applied to femoral prostheses made with ASTM F138 and ASTM F75 alloys. A hip prosthesis is typically subjected to cyclic loads commensurate with the patient’s weight in response to each step and hence requires a cyclic compression stress approach. Austenitic stainless steels have been used in surgical applications over many years due to low cost, good mechanical properties and resistance to corrosion. The CrCoMo alloy features higher corrosion resistance compared to ASTM F138 stainless steel. In order to perform finite element analysis, two software were used: Autodesk® Inventor® 2013 and Autodesk® Simulation 2015. The formatting of the simulation followed the parameters established in the ISO 7206-4: 2016 ABNT NBR standard, the applied load was 2,3 kN with an angle of 10 degrees with respect to the frontal plane and 9 degrees with respect to the lateral plane. As for the static analysis, the prosthesis composed of ASTM F138 material presented satisfactory results, and the prosthesis made with the ASTM F75 alloy failed. Both prostheses did not exceed 5 million cycles in the dynamic load application.
Anisotropy of glancing angle deposited films: results of atomistic simulation
Authors: Grigoriev F V , Sulimov V B , Tikhonravov A V
Published: February 2021

Anisotropy of SiO2 films fabricated by glancing angle deposition is investigated using the classical atomistic simulation and anisotropic Bruggeman effective medium theory. The voids between the slanted columns, occurring as a result of glancing angle deposition, are considered as ellipsoids. Averaged shape parameters of these ellipsoids are defined using the density gradient tensor. Calculated values of difference of refractive index components of glancing angle deposited SiO2 films are in accordance with experiment.
Predicting entanglement and coherent times in FMO complex using the HEOM method
Authors: González-Soria Bruno , Delgado Francisco , Anaya-Morales Alan
Published: February 2021

Fenna-Matthews-Olson (FMO) bacteriochlorophylls (BChls) are molecules responsible of the high efficiency energy transfer in the photosynthetic process of green sulfur bacteria, controversially associated to quantum phenomena of long lived coherence. This phenomenon is modelled using Quantum Open Systems (QOS) without include memory effects of the surrounding approximated as a phonon bath on thermal equilibrium. This work applies the Hierarchical Equations of Motion method (HEOM), a non-Markovian approach, in the modelling of the system evolution of FMO complex to perform predictions about the coherence times scales together with global and semi-local entanglement during the quantum excitation.
Finsler geometry modeling for anisotropic diffusion in Turing patterns
Authors: Koibuchi Hiroshi , Okumura Masahiko , Noro Shuta
Published: February 2021

Turing patterns are known to be described by diffusion reaction (DR) equations, and the patterns become zebra-like anisotropic if the diffusion constant is directionally dependent. However, the origin of this dependence is unclear. In this study, we report that Turing patterns can be studied with the Finsler geometry (FG) modeling technique by applying a hybrid numerical technique, which combines DR equations and the Monte Carlo (MC) technique. In the DR equations and the Hamiltonian for MC, the Finsler metric is introduced using internal degrees of freedom. We numerically show that anisotropic patterns appear according to a constraint given by some external forces applied to the internal degrees of freedom. In this FG modeling technique, direction-dependent diffusion constants are unnecessary, and these constants automatically or effectively become anisotropic. We consider that the internal degrees of freedom introduced for the Finsler metric play an essential role in the anisotropic patterns.
Finsler geometry modeling of complex fluids: reduction in viscous resistance
Authors: Okumura Masahiko , Homma Ippei , Noro Shuta , Koibuchi Hiroshi
Published: February 2021

Complex fluids refer to a broad range of materials that contain two different phases, such as solid-liquid and fluid-gas mixtures. Generally, in fluids with dispersed matter, the viscous resistance is not always proportional to the velocity of the fluids, and a fluid exhibiting such behavior is called a non-Newtonian fluid. The viscous resistance is considerably decreased in a certain range of velocities compared to the case without macromolecules. This change in the macroscopic viscous resistance is expected to originate from the interactions between fluids and dispersed matter. In this study, we apply the Finsler geometry (FG) modelling technique to implement this complex interaction, and we numerically show a mechanism for the reduction in viscous resistance. In the FG modeling, a new dynamical variable corresponding to the directional degrees of freedom of dispersed matter is introduced and updated by the Monte Carlo simulation technique during iterations of the Navier-Stokes equation. The tentative results indicate that the distribution of the viscous force and its position dependence are considerably different from those in standard Newtonian fluids. This finding indicates the possibility that the FG modeling technique can properly describe the effects of dispersed matter on the flow behavior.
The influence of isoenergy surface anisotropy and surface scattering kinetics on the conductivity of a thin metal layer
Authors: Savenko O V , Romanov D N , Kuznetsova I A
Published: February 2021

A kinetic theory of the conductivity of a thin metal layer in a longitudinal alternative electric field is constructed. We assume the layer thickness is much greater than the electron de Broglie wavelength and less than the skin layer depth. Therefore, the skin effect is neglected and electron energy spectrum quantization is not considered. The Soffer model is used as the boundary conditions for the Boltzmann equation. We suppose the roughness parameters of the upper and lower layer surface have different values. The Fermi surface is an ellipsoid of revolution, the main axis of which lies in the layer plane. The dependences of conductivity tensor components on the layer thickness, electric field frequency, Fermi surface anisotropy parameter, and surface roughness parameters are analyzed. The results are compared with the ones performed within the framework of diffuse-mirror boundary conditions and with experimental data.
Local mean field approximation applied to a 3D spin crossover nanoparticles configuration: free energy analysis of the relative stability of the stationary states
Authors: Cazelles C. , Linares J. , Singh Y. , Dahoo P.-R. , Boukheddaden K.
Published: February 2021

The local mean field approximation is applied to an inhomogeneous 3D spin crossover (SCO) nanoparticle configuration with a special focus on its systemic effect on molecules in the bulk, at the corner, at the edge and at surface. The matrix effect at the surface is introduced through a specific interaction term, L. The partition function for each region allows the determination of the total free-energy F from which the stability of each configuration is analyzed through thermodynamic considerations.
Structural characteristics of gluconolactone/gluconic acid aqueous solution used for bio battery by molecular dynamics
Authors: Matsunaga Shigeki
Published: February 2021

The structural characteristics of gluconolactone/gluconic acid aqueous solution as a model for the anode of biofuel cells are investigated by molecular dynamics. The molecular structure of components of the solution and the atomic charges are optimized by the density functional theory (DFT) using Gaussian09. The distribution of constituent ions of the solution is investigated by a radial distribution function. The shape change of gluconic acid anions in the solution and the frequency distribution of each ion are also examined.
The optimized approach to get the fundamental property of the gravity assists maneuvers from the Jacobi integral
Authors: Grushevskii Alexey , Golubev Yury , Koryanov Victor , Tuchin Andrey , Tuchin Denis
Published: February 2021

The design of interplanetary trajectories using a series of gravity assists maneuvers begins with the ballistic mission design. It is reasonable to construct the corresponding initial approximation using the patched conics method within the model of the circular restricted three-body problem. Such a construction requires the calculation of the “transfer parameter” Vinf
- the dimensionless asymptotic velocity of the spacecraft relative the target planet, when switching from heliocentric arcs to planetocentric segments and vice versa. In the circular restricted three-body problem model, Vinf
can be calculated using the Jacobi integral J (or using it’s analogue - the Tisserand parameter TTiss
and the basic property of the Jacobi integral for the gravity assists maneuvers within the framework of the circular restricted three body problem:
const J ≈ TTISS ≈ 3 – Vinf Vinf
. According to this property, the J value does not change during the multiple gravity assists maneuvers that preserve the Jacobi integral constant are performed. This fact is known in astrodynamics but it is classically derived in a rather cumbersome method. In this study, a shorter method for its obtaining is proposed. The modifications of the representation of the Jacobi integral in the circular restricted three-body problem for the various configurations of three bodies are presented.
The reachable regions construction for the inelastic anisotropic billiards
Authors: Grushevskii Alexey
Published: February 2021

Modern methods of the ballistic design of space flights (entry of a spacecraft with non-zero aerodynamic quality into the planet’s atmosphere, carrying out gravity assist maneuvers around planets) are associated with the need to calculate a lot of trajectories (i.e. of the phase beams). For their effective use and determination of dynamically admissible reachability regions, it is necessary to identify and study the structure of accompanying singularities of the phase parameters and to construct the corresponding adequate and adaptive models. In this sense, the analogy of the motion of these systems with the singular motion of billiard systems turns out to be very fruitful. First of all, we are talking about anisotropic billiards with dissipation taken into account. In this work, we set and described the model problems about the flat stones skipping on the surface of the water (the ricochets) and an inelastic ball analogue which is bouncing or rolling on an imperfect surface in the presence of a side deviation effect. The main indicatrices types classification for the singular reflection from the plane surface is carried out. Model problems of the ricocheting pebble on the surface of the water surface and the inelastic ball bouncing or rolling on an imperfect surface in the presence of a side bouncing effect also the attainability region problem of the atmospheric entry are posed and described. The configurations of their maximum reachable regions are described
The open unsymmetrical stadium billiard
Authors: Espinoza Ortiz J. S. , Lagos-Monaco R. E.
Published: February 2021

In open billiards a particle can escape from the cavity through a leak. This type of systems have received special attention because of their applications to a wide variety of physical phenomena ranging from hydrodynamics to quantum chaos and astronomy. Chaotic leaked billiards are characterized by a so called transient behavior, i.e. by the presence of chaotic motion with a finite life time impossible to be studied just through the analysis of its asymptotic behavior. Under this scenario, we consider the quarter stadium billiard to study the influence of leaking marginal unstable periodic orbits. A rigorous statistical analysis of the survival probability is presented, setting up the classical trajectories’ solution in such a way that the system only depends on its partial separability and construct the Birkhoff map. The possibility of more than one leak into a billiard is also considered
General mathematical model for energetic and informatic evaluated over natively producing surrounded systems
Authors: Zakharov V K
Published: February 2021

Some joint (synthetic) closed in itself idea about the world and its being is expounded in the paper, which gives the opportunity to invent the parallel definitions of the energy and the information not exceeding the bounds of the united world. This allows us to introduce some sufficiently general notion of the evaluated (over natively) producing (transmission stream conservatively-dynamic) surrounded system, described by the proper system of evolutional equations. In the capacity of important partial cases of such systems the proper notions of the energetic evaluated producing surrounded system and the informatic* evaluated producing surrounded system are introduced. The explicitly analyzed earlier examples of the model of heating stove (as the energetic evaluated producing surrounded system) and the model of personal computer (as the informatic evaluated producing surrounded system) expose the applicability of proposed idea to a generalized and formalized description of some wide class of over native systems really existing.
Biophysical parameters affecting lung surfactant function, surface tension and the transition from aerosol to droplet exhalation (in relation to COVID-19 infection)
Authors: Allaerts W
Published: February 2021

A considerable number of biophysical and biochemical studies has increased our understanding of the surface activity of surfactant proteins B and C (SP-B, SP-C) in the (mammalian) lung and their importance for a healthy, proper breathing system. For instance, it is well-known that these surfactant proteins are released from the lamellar bodies of type II cells of the lung alveoli (type II pneumocytes), and that at compression, the lipid-protein monolayer of the surfactant is squeezed into three-dimensional (3D) stacks, acting as a surfactant reservoir. Moreover, studies have demonstrated the influence of hydrophobic nanoparticles on lung surfactant model systems, well before the outbreak of the COVID-19 pandemic. The potentially devastating effect of SARS-CoV-2 infection on vital lung function, including pneumonia and Acute respiratory distress syndrome (ARDS), meanwhile has been confirmed worldwide by thousands of fatal cases, although the mechanism of its onset is not completely understood. In theory, any virus carrying palmitoylated spike proteins (like beta-coronaviruses in general) might interfere with the alveolar surface activity, when infecting the deep respiratory system. However, it is clearly established that SARS-CoV-2 uses the Angiotensin converting enzyme 2 receptor (ACE2) for entry in the host, which receptor is expressed on the same type II pneumocytes, and, as a result, the virus may directly interfere with the secretion of surfactant proteins. This study aims at elucidating the main targets for containment of the spread of the SARS-CoV-2 virus via the respiratory system, a better understanding of the role of virus-surfactant interactions, the formation of aerosols and role of the inflammatory components of the immune system, as well as the role of positive pressure ventilation systems on particle exhalation, as being used at ICUs. Finally, suggestions are made for important goals for future biophysics research in infectious disease prevention and containment.