bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-exercise Heart Rate Variability: Whole-body
Cryotherapy vs. Contrast Water Therapy
Authors: Sautillet Benoît , Leprêtre Pierre Marie , Schmitt Laurent , Ahmaidi Said , Costalat Guillaume
Published: March 2021

High-intensity training sessions are known to alter cardiac
autonomic modulation. The purpose of this study was to
compare the effects of whole-body cryotherapy, contrast
water therapy and passive recovery on the time course of
cardiac autonomic markers following a standardized HIT
session. Eleven runners completed a high intensity session
followed by one of the following recovery interventions:
whole-body cryotherapy, contrast water therapy or passive
recovery. Changes in cardiac autonomic modulation were
assessed in supine and standing positions during an active
tilt test at pre-, post-14 h and post-38 h. In supine,
high-frequency power increased from pre- to post-14 h
following whole-body cryotherapy (1661.1±914.5 vs.
2799.0±948.4 ms2, respectively; p=0.023) and
contrast water therapy (1906.1±1327.9 vs. 4174.3±2762.9
ms2, respectively; p=0.004) whereas high
frequency power decreased in response to passive recovery
(p=0.009). In standing, low-frequency power increased from
pre-to post-38 h (1784.3 ± 953.7 vs.
3339.8±1862.7 ms2, respectively; p=0.017)
leading to an increase in total power from pre- to post-38 h
(1990.8 ± 1089.4 vs. 3606.1±1992.0 ms2,
respectively; p=0.017). Spectral analysis revealed that
contrast water therapy appears to be a more efficient
recovery strategy than whole-body cryotherapy in restoring
cardiac autonomic homeostasis.
Deutschsprachige Terminologie der revidierten Atlanta-Klassifikation bei akuter Pankreatitis: Glossar basierend auf der aktuellen S3-Leitlinie zur akuten, chronischen und Autoimmunpankreatitis
Authors: Schreyer Andreas G. , Seidensticker Max , Mayerle Julia , Lerch Markus M. , Juchems Markus S. , Wessling Johannes , Ringe Kristina Imeen , Grenacher Lars
Published: March 2021

Die im Jahr 1992 veröffentlichte Atlanta-Klassifikation zur Beurteilung von Schweregraden und Komplikationen der akuten Pankreatitis sollte ursprünglich eine einheitliche Terminologie für Kliniker und Forscher etablieren. Nach einer kontinuierlichen Weiterentwicklung wurde dann 2012 die revidierte Atlanta-Klassifikation publiziert, um die Aspekte der Bildgebung besser zu integrieren sowie Unschärfen in der Terminologie zu optimieren. Diese Begrifflichkeiten bezüglich der Krankheitseinteilung, -phasen, Schweregradbeurteilung und lokaler Komplikationen lagen bisher lediglich als englische Ausdrücke vor. Dies verhinderte eine weitere Verbreitung und Anwendung im klinischen Alltag im deutschsprachigen Raum. Um eine Anpassung in der deutschsprachigen Medizin zu erreichen, wurden die Termini der revidierten Atlanta-Klassifikation durch ein Expertenteam der Deutschen Röntgengesellschaft basierend auf aktueller Literatur übersetzt und im Rahmen der Konsensuskonferenz der neu erstellten S3-Leitlinie Pankreatitis im Februar 2020 mit einer Zustimmung von 97,3 % als Teil der Leitlinienempfehlung angenommen. Im folgenden Text mit Glossar werden die übersetzten und konsentierten Begrifflichkeiten anhand von Bildbeispielen erläutert.

Kernaussagen:
Disinfectants Used in Stomatology and SARS-CoV-2 Infection
Authors: Stawarz-Janeczek Magdalena , Kryczyk-Poprawa Agata , Muszyńska Bożena , Opoka Włodzimierz , Pytko-Polończyk Jolanta
Published: March 2021

Effective disinfection is a basic procedure in medical facilities, including those conducting dental surgeries, where treatments for tissue discontinuity are also performed, as it is an important element of infection prevention. Disinfectants used in dentistry and dental and maxillofacial surgery include both inorganic (hydrogen peroxide, sodium chlorite-hypochlorite) and organic compounds (ethanol, isopropanol, peracetic acid, chlorhexidine, eugenol). Various mechanisms of action of disinfectants have been reported, which include destruction of the structure of bacterial and fungal cell membranes; damage of nucleic acids; denaturation of proteins, which in turn causes inhibition of enzyme activity; loss of cell membrane integrity; and decomposition of cell components. This article discusses the most important examples of substances used as disinfectants in dentistry and presents the mechanisms of their action with particular focus on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The search was conducted in ScienceDirect, PubMed, and Scopus databases. The interest of scientists in the use of disinfectants in dental practice is constantly growing, which results in the increasing number of publications on disinfection, sterilization, and asepsis. Many disinfectants often possess several of the abovementioned mechanisms of action. In addition, disinfectant preparations used in dental practice either contain one compound or are frequently a mixture of active compounds, which increases their range and effectiveness of antimicrobial action. Currently available information on disinfectants that can be used to prevent SARS-CoV-2 infection in dental practices was summarized.
Electron-optical system for dual radial sheet beams for Ka-band cascaded angular log-periodic strip-line traveling wave tube
Authors: He Tenglong , Wang Shaomeng , Wang Zhanliang , Shao Wei , Xu Duo , Li Xinyi , Wang Hexin , Gong Huarong , Lu Zhigang , Duan Zhaoyun , Aditya Sheel , Gong Yubin
Published: March 2021

A novel electron-optical system is proposed for dual azimuthally stacked radial sheet electron beams (ARSEBs). The two sheet beams are emitted from curved surfaces of two cathodes and are focused by a focusing electrode, which is carefully designed to produce a symmetric field distribution for the two beams and to avoid interference between the beams. A common tunable periodic cusped magnetic focusing system is also designed to focus the two ARSEBs. The dual sheet beams are used in a traveling wave tube (TWT) consisting of a cascade of two azimuthally supported angular log-periodic strip-line (ASALS) slow-wave structures (SWSs). The transmission efficiency in the presence of beam–wave interaction is 93%. The particle-in-cell simulation results show that for a beam voltage of 4400 V and a current of 0.39 A, the proposed cascaded TWT has a maximum gain of 32.5 dB at 35 GHz and a maximum output power of 180 W; this is a significant gain improvement over a TWT using a single ASALS SWS.
Two-dimensional spectroscopy beyond the perturbative limit: The influence of finite pulses and detection modes
Authors: Anda André , Cole Jared H.
Published: March 2021

Ultra-fast and multi-dimensional spectroscopy gives a powerful looking glass into the dynamics of molecular systems. In particular, two-dimensional electronic spectroscopy (2DES) provides a probe of coherence and the flow of energy within quantum systems, which is not possible with more conventional techniques. While heterodyne-detected (HD) 2DES is increasingly common, more recently fluorescence-detected (FD) 2DES offers new opportunities, including single-molecule experiments. However, in both techniques, it can be difficult to unambiguously identify the pathways that dominate the signal. Therefore, the use of numerically modeling of 2DES is vitally important, which, in turn, requires approximating the pulsing scheme to some degree. Here, we employ non-perturbative time evolution to investigate the effects of finite pulse width and amplitude on 2DES signals. In doing so, we identify key differences in the response of HD and FD detection schemes, as well as the regions of parameter space where the signal is obscured by unwanted artifacts in either technique. Mapping out parameter space in this way provides a guide to choosing experimental conditions and also shows in which limits the usual theoretical approximations work well and in which limits more sophisticated approaches are required.
Enhancing magneto-optic effects in two-dimensional magnets by thin-film interference
Authors: Hendriks F. , Guimarães M. H. D.
Published: March 2021

The magneto-optic Kerr effect is a powerful tool for measuring magnetism in thin films at microscopic scales, as was recently demonstrated by the major role it played in the discovery of two-dimensional (2D) ferromagnetism in monolayer CrI3 and Cr2Ge2Te6. These 2D magnets are often stacked with other 2D materials in van der Waals heterostructures on a SiO2/Si substrate, giving rise to thin-film interference. This can strongly affect magneto-optical measurements but is often not taken into account in experiments. Here, we show that thin-film interference can be used to engineer the magneto-optical signals of 2D magnetic materials and optimize them for a given experiment or setup. Using the transfer matrix method, we analyze the magneto-optical signals from realistic systems composed of van der Waals heterostructures on SiO2/Si substrates, using CrI3 as a prototypical 2D magnet, and hexagonal boron nitride to encapsulate this air-sensitive layer. We observe a strong modulation of the Kerr rotation and ellipticity, reaching several tens to hundreds of milliradians, as a function of the illumination wavelength, and the thickness of SiO2 and layers composing the van der Waals heterostructure. Similar results are obtained in heterostructures composed by other 2D magnets, such as CrCl3, CrBr3, and Cr2Ge2Te6. Designing samples for the optimal trade-off between magnitude of the magneto-optical signals and intensity of the reflected light should result in a higher sensitivity and shorter measurement times. Therefore, we expect that careful sample engineering, taking into account thin-film interference effects, will further the knowledge of magnetization in low-dimensional structures.
Modeling of electron transfer phenomenon in the dinuclear {Fe(μ − CN)Co} complexes
Authors: Klokishner Sophia , Ostrovsky Serghei
Published: March 2021

A model is developed to describe the charge transfer-induced spin transition in a crystal containing cyanide-bridged binuclear Co–Fe clusters as a structural element. The model accounts for the electronic states arising from two cluster configurations active in the transition and, namely, from the ground ls-CoIII−ls-FeII and the excited hs-CoII−ls-FeIII ones. The cooperative interaction that originates from the coupling of the acoustic crystalline modes with the molecular vibrations describing the displacements of the nearest ligand surroundings of the metal ions is assumed to be responsible for spin transformation. The problem of interacting clusters is solved within mean field approximation. The role of the order parameters is played by the mean values of the products of the electronic matrices and coordinates of the molecular vibrations in the ground and excited cluster configurations. The developed model provides quite a reasonable description of the observed temperature dependence of the magnetic characteristics of the [{(Tp)Fe(CN)3}{Co-(PY5Me2)}](CF3SO3)⋅2DMF complex. The factors controlling the electron transfer in this complex are elucidated.
School-based integrated healthcare model: how Our Mia Mia is improving health and education outcomes for children and young people
Authors: Mendoza Diaz Antonio , Leslie Andrew , Burman Charlotte , Best James , Goldthorp Kristie , Eapen Valsamma
Published: March 2021

Integrating healthcare into education settings represents a promising model to address complex health problems in disadvantaged communities through improving access to health and social services. One such example of an effective school-based health hub is the Our Mia Mia (OMM) Wellbeing Hub, located in a primary school in Nowra and servicing a community experiencing significant socioeconomic disadvantage. The efficacy of OMM rests on its success in facilitating access to services by removing the barriers of cost and transport and establishing connection to community. The OMM fosters collaborations between health professionals and educators to coordinate holistic treatment and implement appropriate student supports in a timely manner. The support of key individuals and groups, in addition to the flexibility of the model, has allowed the hub to pivot and adapt to meet the changing needs of its community, particularly as challenges pertaining to bureaucracy, financial sustainability and community mistrust have presented themselves. Future directions for the OMM hub, and the possibility of adapting and translating school-based healthcare delivery models in other disadvantaged communities, is discussed.
Patterns of conflict speech and young adult feminist identity construction on Tumblr
Authors: Cosper Caitlin
Published: March 2021

Interactions on social media platforms are becoming increasingly relevant from an identity construction
perspective. Conflict speech, in particular, is a form of interaction that is especially common in online spaces and constructs
identity through polarization, strengthening the in-group while excluding the out-group. The young adult feminist identity has
established a strong presence in online spaces, specifically the microblogging platform Tumblr. This study seeks to analyze the
role of conflict speech in young adult feminist identity construction through focusing on recontextualization of comments and
name-calling strategies. Within this analysis, it is possible to determine the importance of conflict speech as it strengthens the
collective feminist identity while allowing those in the in-group to exclude and dismiss conflictual comments stemming from those
in the out-group.
‘Slut I hate you’
Authors: Sagredos Christos , Nikolova Evelin
Published: March 2021

Adopting a Critical Discourse Analysis perspective, this paper seeks to explore the conflict emerging from the
ways YouTube users index, reaffirm or challenge gender ideologies by examining 2,304 YouTube comments posted in response to the
misogynistic Greek pop song Καριόλα σε μισώ ‘Slut I hate you’. Our textual analysis draws on the Discourse-Historical Approach, focusing on the lexicogrammatical choices and discursive strategies employed for the positive presentation of
the self and the negative presentation of the other. Our findings suggest that: (a) there is a dialectic relationship between the
gendered representations of the videoclip and the gender ideologies indexed by individual YouTube users; (b) the discursive negotiation
of gender ideologies in anonymous, asynchronous and polylogal discussions is a highly polarised and antagonistic discourse
activity, with most comments under the videoclip of the song falling under two broad categories, i.e. those sustaining and those
challenging gendered aggression and patriarchal discourses; (c) although both groups resort to common discursive strategies (e.g.
nomination and predication strategies that legitimise the authority of the in-group and delegitimise the out-group), they differ
significantly in their argumentation and intensification/mitigation strategies, which allows commenters to take sides in a polarised
debate and index their gender ideologies; (d) due to the pervasive power of dominant ideologies across all levels of context, the
democratic and subversive potential of conflict on YouTube is limited but not pointless as counter-discourses may still gain
visibility.
Autophagy facilitates mitochondrial rebuilding after acute heat stress via a DRP-1–dependent process
Authors: Chen Yanfang , Leboutet Romane , Largeau Céline , Zentout Siham , Lefebvre Christophe , Delahodde Agnès , Culetto Emmanuel , Legouis Renaud
Published: March 2021

Acute heat stress (aHS) can induce strong developmental defects in Caenorhabditis elegans larva but not lethality or sterility. This stress results in transitory fragmentation of mitochondria, formation of aggregates in the matrix, and decrease of mitochondrial respiration. Moreover, active autophagic flux associated with mitophagy events enables the rebuilding of the mitochondrial network and developmental recovery, showing that the autophagic response is protective. This adaptation to aHS does not require Pink1/Parkin or the mitophagy receptors DCT-1/NIX and FUNDC1. We also find that mitochondria are a major site for autophagosome biogenesis in the epidermis in both standard and heat stress conditions. In addition, we report that the depletion of the dynamin-related protein 1 (DRP-1) affects autophagic processes and the adaptation to aHS. In drp-1 animals, the abnormal mitochondria tend to modify their shape upon aHS but are unable to achieve fragmentation. Autophagy is induced, but autophagosomes are abnormally elongated and clustered on mitochondria. Our data support a role for DRP-1 in coordinating mitochondrial fission and autophagosome biogenesis in stress conditions.
Microtubules form by progressively faster tubulin accretion, not by nucleation–elongation
Authors: Rice Luke M. , Moritz Michelle , Agard David A.
Published: March 2021

Microtubules are dynamic polymers that play fundamental roles in all eukaryotes. Despite their importance, how new microtubules form is poorly understood. Textbooks have focused on variations of a nucleation–elongation mechanism in which monomers rapidly equilibrate with an unstable oligomer (nucleus) that limits the rate of polymer formation; once formed, the polymer then elongates efficiently from this nucleus by monomer addition. Such models faithfully describe actin assembly, but they fail to account for how more complex polymers like hollow microtubules assemble. Here, we articulate a new model for microtubule formation that has three key features: (1) microtubules initiate via rectangular, sheet-like structures that grow faster the larger they become; (2) the dominant pathway proceeds via accretion, the stepwise addition of longitudinal or lateral layers; and (3) a “straightening penalty” to account for the energetic cost of tubulin’s curved-to-straight conformational transition. This model can quantitatively fit experimental assembly data, providing new insights into biochemical determinants and assembly pathways for microtubule nucleation.
Shape reconstruction in linear elasticity: standard and linearized monotonicity method
Authors: Eberle Sarah , Harrach Bastian
Published: March 2021

In this paper, we deal with the inverse problem of the shape reconstruction of inclusions in elastic bodies. The main idea of this reconstruction is based on the monotonicity property of the Neumann-to-Dirichlet operator presented in a former article of the authors. Thus, we introduce the so-called standard as well as linearized monotonicity tests in order to detect and reconstruct inclusions. In addition, we compare these methods with each other and present several numerical test examples.
Reflection and refraction of an electron spin at the junction between two quasi-two-dimensional regions with and without spin-orbit interaction
Authors: Bandyopadhyay Supriyo , Cahay Marc , Ludwick Jonathan
Published: March 2021

We derive the reflection and refraction laws for an electron spin incident from a quasi-two-dimensional medium with no spin–orbit interaction on another with both Rashba and Dresselhaus spin–orbit interaction using only energy conservation. We obtain the well-known result that for an incident angle, there can be generally two different refraction angles for refraction into the two spin eigenstates in the refraction medium, resulting in two different ‘spin refractive indices’ and two critical angles for total internal reflection. We derive expressions for the spin refractive indices, which are not constant for a given medium but depend on the incident electron’s energy. If the effective mass of an electron in the refraction medium is larger than that in the incidence medium, then we show that for some incident electron energies and potential barrier at the interface, the spin refractive index of the incidence medium can lie between the two spin refractive indices of the refraction medium, resulting in only one critical angle. In that case, if the incident angle exceeds that critical angle, then refraction can occur into only one spin eigenstate in the refraction medium. If the system is engineered to make this happen, then it will be possible to obtain a very high degree of spin-polarized injection into the refraction medium. The amplitudes of reflection of the incident spin into its own spin eigenstate and the orthogonal spin eigenstate (due to spin flip at the interface), as well as the refraction amplitudes into the two spin eigenstates in the refraction medium are derived for an incident electron (with arbitrary spin polarization and incident energy) as a function of the angle of incidence.
Features of 3D magneto-convective nonlinear radiative Williamson nanofluid flow with activation energy, multiple slips and Hall effect
Authors: Nandi Susmay , Kumbhakar Bidyasagar , Shanker Seth Gauri , J Chamkha Ali
Published: March 2021

In this article, the impacts of Hall current and Arrhenius activation energy on three-dimensional hydromagnetic Williamson nanofluid flow past a slendering stretching sheet in the presence of multiple slips, viscous dissipation, Joule heating and binary chemical reaction is analyzed. The presence of nonlinear thermal radiation and nonlinear mixed convection is also taken into consideration. The dimensional governing equations are transformed into non-dimensional ordinary differential equations by using some suitable similarity transformation. The resulting coupled and highly nonlinear boundary value problem is then solved numerically by shooting technique based on Runge-Kutta-Fehlberg method. The behaviors of concentration, temperature and velocity distributions w.r.t. the various controlling parameters are illustrated graphically. However, the numerical values of local skin-friction coefficients, local heat and mass transfer rates are explained and presented in tabular form. Furthermore, a result validation is performed to check the accuracy and correctness of the obtained results by comparing the results with previously published results for some limited case of the present problem and an excellent agreement is found between the results.
Natural inflation with a nonminimal coupling to gravity
Authors: Reyimuaji Yakefu , Zhang Xinyi
Published: March 2021

Although natural inflation is a theoretically well-motivated model for cosmic inflation, it is in tension with recent Planck cosmic microwave background anisotropy measurements. We present a way to alleviate this tension by considering a very weak nonminimal coupling of the inflaton field to gravity in both contexts of metric and Palatini formulations of general relativity. We start our discussions with a generic form of the inflaton coupling to the Ricci scalar, then focus on a simple form to do phenomenological study. Our results show that such an extension can bring natural inflation's predictions to a good agreement with the Planck data. Depending on values of the coupling constant ξ and the symmetry breaking scale f, we find that with |ξ|∼ 10-3 and f≳ 2.0 Mpl predictions of the model stay inside 68% CL allowed region until f increases up to 7.7 Mpl, then only inside 95% CL region after f exceeds the latter value. The predictions from the metric and the Palatini theories are very similar due to the simple form of the coupling function we use and the small magnitude of the coupling ξ. Successful reheating can also be realized in this model.
Self-assembly 2D plasmonic nanorice film for surface-enhanced Raman spectroscopy*
Authors: Liu Tingting , Liu Chuanyu , Shi Jialing , Zhang Lingjun , Sun Xiaonan , Huang Yingzhou
Published: March 2021

As an ultrasensitive sensing technology, the application of surface enhanced Raman spectroscopy (SERS) is one interesting topic of nano-optics, which has huge application prospectives in plenty of research fields. In recent years, the bottleneck in SERS application could be the fabrication of SERS substrate with excellent enhancement. In this work, a two-dimensional (2D) Ag nanorice film is fabricated by self-assembly method as a SERS substrate. The collected SERS spectra of various molecules on this 2D plasmonic film demonstrate quantitative detection could be performed on this SERS substrate. The experiment data also demonstrate this 2D plasmonic film consisted of anisotropic nanostructures has no obvious SERS polarization dependence. The simulated electric field distribution points out the SERS enhancement comes from the surface plasmon coupling between nanorices. And the SERS signals is dominated by molecules adsorbed at different regions of nanorice surface at various wavelengths, which could be a good near IR SERS substrate for bioanalysis. Our work not only enlarges the surface plasmon properties of metal nanostructure, but also exhibits the good application
prospect in SERS related fields.
Effects of short-range attraction on Jamming transition*
Authors: Xu Zhenhuan , Wang Rui , Cui Jiamei , Liu Yanjun , Zheng Wen
Published: March 2021

Enormous progresses to understand the jamming transition have been driven via simulating purely repulsive particles which were somehow idealized in the past two decades. While the attractive systems are both theoretical and practical compared with repulsive systems. By studying the statistics of rigid clusters, we find that the critical packing fraction ϕ
c varies linearly with attraction μ for different system sizes when the range of attraction is short. While for systems with long-range attractions, however, the slope of ϕ
c appears significantly different, which means that there are two distinct jamming scenarios. In this paper, we focus our main attention on short-range attractions scenario and define a new quantity named “short-range attraction susceptibility” χ
p, which describes the degree of response of the probability of finding jammed states p
j to short-range attraction strength μ. Our central results are that χ
p diverges in the thermodynamic limit as

χ
p

∝
|
ϕ
−

ϕ
c
∞

|

−

γ
p

, where

ϕ
c
∞

is the packing fraction at the jamming transition for the infinite system in the absence of attraction. χ
p obeys scaling collapse with a scaling function in both two and three dimensions, illuminating that the jamming transition can be considered as a phase transition as proposed in previous work.
ISSDE: A Monte Carlo implicit simulation code based on Stratonovich SDE approach of Coulomb collision*
Authors: Zheng Yifeng , Xiao Jianyuan , Wang Yanpeng , Zheng Jiangshan , Zhuang Ge
Published: March 2021

A Monte Carlo implicit simulation program, Implicit Stratonovich Stochastic Differential Equations (ISSDE), is developed for solving stochastic differential equations (SDEs) that describe plasmas with Coulomb collision. The basic idea of the program is the stochastic equivalence between the Fokker–Planck equation and the Stratonovich SDEs. The splitting method is used to increase the numerical stability of the algorithm for dynamics of charged particles with Coulomb collision. The cases of Lorentzian plasma, Maxwellian plasma and arbitrary distribution function of background plasma have been considered. The adoption of the implicit midpoint method guarantees exactly the energy conservation for the diffusion term and thus improves the numerical stability compared with conventional Runge–Kutta methods. ISSDE is built with C++ and has standard interfaces and extensible modules. The slowing down processes of electron beams in unmagnetized plasma and relaxation process in magnetized plasma are studied using the ISSDE, which shows its correctness and reliability.
Resistivity minimum emerges in Anderson impurity model modified with Sachdev–Ye–Kitaev interaction*
Authors: Zhang Lan , Zhong Yin , Luo Hong-Gang
Published: March 2021

We investigate a modified Anderson model at the large-N limit, where the Coulomb interaction is replaced by the Sachdev–Ye–Kitaev random interaction. The resistivity of conduction electron ρ
c has a minimum value around temperature T*, which is similar to the Kondo system, but the impurity electron’s density of state A
d(ω) demonstrates no sharp-peak like the Kondo resonance around the Fermi surface. This provides a counterintuitive example where resistivity minimum exists without Kondo resonance. The impurity electron’s entropy S
d and specific heat capacity C
v show a crossover from Fermi liquid to a non-Fermi liquid behavior dependent on temperature. The system is a Fermi liquid at T < T*, and becomes a non-Fermi liquid at T > T*, and then becomes a Fermi gas at sufficiently high temperatures T ≫ T*. The non-Fermi liquid at the intermediate-T regime does not occur in the standard Anderson model. We also make a renormalization group analysis, which confirms the crossover from Fermi liquid to the non-Fermi behavior. It is emphasized that the resistivity minimum emerges in our model when the system behaves as a non-Fermi liquid rather than Fermi liquid, which provides an alternative example showing resistivity minimum in condensed matter physics.
X International Congress of Physics Engineering
Authors: Granados Samaniego J , Tavera Romero F , López Gonsález G , Rios Maravilla A
Published: March 2021

1. Introduction

The First International Congress of Physics Engineering was held at the Universidad Autónoma Metropolitana in Azcapotzalco in November 1999, to commemorate the 25th anniversary of Physical Engineering in Mexico and the 25th Anniversary of the creation of the Universidad Autónoma Metropolitana.

The fundamental purpose for which this congress was created was that on the Azcapotzalco campus an international scientific event were held in which the students and teachers of our institution could live with renowned foreign researchers and know the research work that is carried out in other countries and their results, as well as establish academic relationships and cooperation ties. This congress has been held every two years and in it have participated highly renowned scientifics as special guests, coming from various countries both in Europe and North America, South America and the Caribbean, as well as national institutions of the interior of the country and the Mexico City.

This congress has been strongly supported since its creation by prestigious academic institutions in Mexico, such as the National Polytechnic Institute, CINVESTAV, CICATA, the National Autonomous University of Mexico, the Research Center in Optics, the National Institute of Astrophysics Optics and Electronics.

Works submitted extensively to Congress undergoes a single blind peer arbitration process. Those who are accepted are presented orally and subsequently published in the Journal of Physics: Conference Series of the Institute of Physics of Great Britain, in Open Access for international dissemination.

List of Justification, Results, Remote communication, Organizing committee, Local Committee, International Scientific Committee, Editorial Committee, Aknowledgments and Sponsors are available in this pdf.
Thermomechanical and annealing processing effect on a rapid solidified Co – 20 wt. % Cr alloy
Authors: Luna-Manuel J C , Lagar-Quinto S , Ramirez-Ledesma A L , Juarez-Islas J A
Published: March 2021

The microstructure influence on the mechanical properties in a rapid solidified Co – 20 wt. % Cr alloy processed by hot – rolling (HR), and hot – rolling plus annealing (HR +A) is presented. The characterization consisted of a scanning electron microscopy inspection and its correlation with hardness, tensile test measurements and the corresponding fractography. The results showed that the as – cast (AC) condition is conformed by columnar dendrites aligned on a preferential direction. Additionally, numerous striations associated with the massive athermal transformation were observed. From the hot – rolled condition, athermal ε – martensite plates inside block austenitic grains were identified. On the other hand, the specimen subjected to hot – rolling plus annealing treatment showed an important internal stresses relief, reflected in the ductility improvement from 4.3 ± 2.18 % in the AC condition, and 13.73 ± 3.74 % in the HR condition to 27.8 ± 4.35 % for the HR + A condition.
On the strengthening mechanisms of a cross – rolled Zn – based bioabsorbable alloy
Authors: Domínguez-Contreras L A , Cruz-Herrera G A , Ramírez-Ledesma A L , Juárez-Islas J A
Published: March 2021

The Zn-Ag-Mg alloy system is a promising candidate material for a wide range of applications in the biomedical field. In this study, two rolling routes: unidirectional rolling (UR) and cross rolling (CR), were applied to induced different microstructural features on the presented Zn alloy. It was experimentally demonstrated that rolling in different ways, modifies the microstructural features from the as-cast condition and have a dramatic impact on the Zn-based alloy mechanical behavior. The better balance between yield strength (YS), ultimate strength (UTS) and elongation (%E) was obtained from the Zn-10.0Ag-1.0Mg alloy in CR with values ∼250MPa, ∼330MPa and ∼30, respectively.
Automatic bottling Machine
Authors: Aragón-Gonzáles G , Barragán-Santiago I , Huerta-Rizo E , León-Galicia A
Published: March 2021

A Mexican manufacturing plant, whose main product is bottled Pox (a traditional Mexican alcoholic beverage), requested the design and construction of an automatic bottling machine able to fill six bottles of 750 milliliters per minute and satisfy the exigencies of the Mexican regulation NOM-002-SCFI-2011. To develop this machine it was necessary, as a first step, to make an experimental study to determine the adequate dosage method to use, resulting in a dosage controlled with an electrical sensor that detects the free surface of the liquid inside the bottle. The automatic bottling machine is composed of four modules to fulfill the continuous supply of bottles and the liquid dosage. To command the complete control system and perform the automatic functions of the machine, an Arduino UNO board was adopted. The result of the work generated a versatile, efficient machine with a robust control system, able to dosage 250 to 4’000 ml volumes, not only for alcoholic beverages but for any liquid with viscosity and electrical conductivity similar to water, with an error not bigger than 15 ml.
Magnetoimpedance effect in amorphous Co-rich ferromagnetic microwires and its application as low-field sensor
Authors: López-Ortega C H , Montiel H
Published: March 2021

The magnetoimpedance in amorphous microwires with a nominal composition of Co67Fe4Si14B15 has been investigated. The measurements were carried out with an Agilent 4395A network analyzer in the frequency range from 100 kHz to 60 MHz. The experimental setup for magnetoimpedance measurements and the analysis of the results are presented. Our results show that an optimum frequency exists, where the magnetoimpedance ratio is maximum for all studied frequencies. In this frequency, the amorphous microwire is very sensitive to variations of the dc magnetic field. Therefore, we propose a possible application as a low dc field sensor.
Quantum classical correspondence for the statistical moments of eigenfunctions in closed systems with chaotic dynamics
Authors: Hernández-Saldaña H
Published: March 2021

Quantum classical correspondence, QCC, is a wide subject of interest from the historical approaches to current studies in simple and complex systems, including time dependent Hamiltonians. Quantum eigenfunctions, or wave-functions, are part of the quantities analysed in recent years, including the implementation due to M V Berry and A Voros in 1977 of a suitable quantity to be considered as the classical eigenfunction counterpart. Here we present the calculation of the statistical moments of eigenfunctions in energy representation for anharmonic oscillators. The classical counter part of the system is fully chaotic. The comparison of the quantum version in order to test for quantum classical correspondence is analysed using a slightly modified formula of the proposed by Berry and Voros. The agreement is good with the corresponding classical counterpart being at the bottom of the quantum version for all the energy range considered.
Evolution of Morphology, Structure and Emission in Si-rich HfO2:Nd films with Annealing Times
Authors: Rivero A , Torchynska T , Vega L , Casas J , Khomenkova L , Gourbilleau F
Published: March 2021

The impact of the time at high temperature annealing on the morphology, crystal structure and emission in visible spectral range has been studied in Si rich HfO2:Nd films produced by radio-frequency magnetron sputtering in pure argon plasma. The annealing was carried out at 900 °C for 1, 5, 10, 30 and 60 min in the nitrogen atmosphere. A set of experimental methods have been used, such as: scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and photoluminescence (PL). In the present work the joint analysis of PL and XRD results permits us to estimate the optimal time parameters of annealing at 900 °C the Si-HfO2: Nd films for obtaining the bright emission via 4f electronic levels of the Nd ions embedded in the tetragonal HfO2 phase mainly after long annealing (30- 60 min). The film oxidation for annealing times (60 min) stimulated some crystal phase transformation with the start of formation of the tetragonal SiO2 phase, that is accompanied by the defect generation and decreasing the PL intensity. The discussion of PL and XRD results is presented in detail.
An equivalent electric circuit as a tool for monitoring micron sized-particles in suspension from electrical impedance measurements
Authors: de León-Hernández A , Sánchez-Pérez C , Ramírez-Chavarría R G
Published: March 2021

In this work, a microfluidic device with a three-electrode system is used to measure the electrical impedance spectrum of micron-sized particles suspended in Phosphate Buffered Saline (PBS). We use polymer particles of 15 μm and 48 μm of diameter, as they can mimic biological cells in suspension. The main purpose is to study the influence of the particle concentration on impedance parameters and to establish the basis for biological cell suspensions assays. An electric equivalent circuit model is used to describe the experimental impedance data. Results show a high dependence of electrical parameters with the mass fraction and particle size. The model considers the resistance of the bulk solution and the electrical double layer, as the two essential electrical elements. Results show a maximum error of 3% by fitting the measurements to the proposed model. This proposal could be of interest for cytotoxicity assays.
Polycrystal x-ray diffraction modelling: grazing incidence versus Bragg-Brentano
Authors: Narvaez-Monroy J , Villalobos-Portillo E , Fuentes-Cobas L , Fuentes-Montero L
Published: March 2021

Diffraction-based texture analysis plays a significant role in the investigation of the physical properties of materials. The development of computer-aided tools for this research area facilitates quantitative validation of proposed orientation distribution models. We analyze the differences between Bragg-Brentano and grazing-incidence diffraction experiments from the point of view of texture characterization. New software packages for modelling Bragg-Brentano and grazing-incidence (one- and two-dimensional) XRD patterns produced by axially-textured polycrystals are presented. A case study based on a virtual experiment with a BaTiO3 sample is presented. The effect of texture on the diffraction patterns obtained by application of the different techniques considered differs significantly.
Ab initio study of optical properties of the [0001] Ti-surface with a carbon layer coverage and of graphene with an extensive Ti coverage
Authors: Zárate A , Salas O , Canales M , Magana L F
Published: March 2021

We used first-principles molecular dynamics at atmospheric pressure and 300 K to simulate a graphene layer, a titanium slab, the high coverage of the graphene layer with titanium, and the masking of the titanium surface with a carbon layer. The calculations were performed using the Quantum Espresso code with the GGA approximation. We then calculated the energy band structure and the optical absorption and reflectivity of the decorated surfaces. We found significant changes in these properties.
Industrial revolution 4.0 on big data adoption factors on social media users and popularity brands
Authors: Sardjono W , Rama Putra G , Selviyanti E , Cholidin A , Salim G
Published: March 2021

The purpose of writing this paper is to look at how factors of big data adoption affect the users of social media and brand popularity. The method used in the writing of this paper is by using path analysis and also by doing literature study to find reference material. The results of the analysis indicate that there is influence of big data adoption factors that affect the popularity of the brand. With this research, we get big data model that influence the brand popularity.
The development of worksheet oriented by visual learning style to measure geometry problem-solving skills
Authors: Shofyan A , Sunardi  , Yuliati N , Nuryami  , Rizkika P
Published: March 2021

Based on information from the math teacher at MTs. Nurul Islam Pasirian-Lumajang (East Java, Indonesia) which has 150 students of grade VII, there is a phenomenon was interesting. Many students like geometry lesson, this can be seen when the learning takes place with the media used interesting and many students like to draw flat shapes. However, when dealing with geometry problems, many students have difficulty determining the solution method. This study aims to develop teaching materials in the form of student worksheets on the circumference and area of a rectangle oriented towards students’ visual learning styles and visual perception skills. Next students will be given a test to analyze the ability to solve problems and in accordance with Polya’s problem solving steps that must be carried out sequentially, namely: understanding the problem, compiling a settlement plan, implementing the settlement plan, and checking the solutions that have been obtained. The development model used is the ADDIE model which includes: (1) Analysis, (2) Design, (3) Development or Production, (4) Implementation, and (5) Evaluation. Geometry material taken in this research is the perimeter and area of the rectangle. The results obtained from the analysis stage, that 50% of students have a visual learning style and for task analysis, the results obtained, of the 10 students who answered correctly there were only 2 students who answered correctly. After students read the material and worked on worksheets oriented to visual learning styles, there was a relatively significant change, out of 10 students there was only 1 student who did not understand in solving geometry problems.
Thinking process of 7th class students in understanding quadrilateral concepts based on Van Hiele theory
Authors: Kusuma M A , Susanto  , Yuliati N , Maharani P , Hasanah N
Published: March 2021

This study describes the thinking process of 7th class students in understanding quadrilateral concepts based on the van hiele theory. This research is a descriptive research with qualitative approach. The research instrument used was the researcher, the latest question sheets and interviews. Data collection methods used were tested and interviews. Data analysis techniques include data reduction, data presentation, and drawing conclusions. The results showed that S1 underwent an assimilation process when determining a rectangle is a parallelogram because S1 can correctly state the reason why a rectangle is a parallelogram. This shows that S1 has met level 2 (Informal Deduction) even though S1 has not been able to prove. S2 undergoes assimilation when answering questions. S2 begins to experience disequilibrium when S2 is asked about the number of vertices as evidenced by long silences. But after being given an understanding of the concept, S2 began to understand and there was an equilibrium. Then S2 experiences, accommodation when restating the nature of the rectangular shape. This shows that S2 has met level 2 (analysis). S3 undergoes an assimilation process because S3 chooses a shape which is a rectangular shape based on S3’s knowledge. This indicates that S3 meets level 0 (Visualization).
The effectiveness of research-based learning model of teaching integrated with computer simulation in astronomy course in improving student computational thinking skills
Authors: Ridlo Z R , Indrawati  , Afafa L , Bahri S , Kamila I S , Rusdianto
Published: March 2021

This research aims to explore students’ computational thinking skills within the implementation of the Research-Based Learning model of Teaching in Astronomy course in Kepler and Titius Bode Laws topics. The research design is comparing the modern class (experimental class) and traditional class with the traditional teaching type. RBL model of Teaching implemented in the experimental class, while direct Teaching implemented in the control class. Computer programming is also integrated into this research related to computational thinking skills. Matlab Software used in this research related to Astronomy course of Kepler’s and Titius Bode’s Laws topics. This research used triangulation methods. The quantitative methods were applied to analyze students’ achievement tests according to computational thinking skills. The Qualitative method was applied using the observation of students’ activity. Students’ achievement tests are represented by pretest and posttest scores. The posttest results for the experimental class were 80.4167 and the control class was 75.8108. The data analysis form pretest and posttest scores indicate a significant value of 0.012 (p ≤ 0.05) with the gain in mean that also emerged in both classes. The average value of student activity for the experimental class was 3.7444 and the control class was 2.4266 from a maximum value of 5. This research results that the RBL accompanied with computer simulations have a significant impact towards students’ computational thinking skills.
Development of science learning devices contexstual problem based learning (CPBL) based in improving problem solving skills for 4th grade elementary school
Authors: Agustoni A , Suratno  , Suparti
Published: March 2021

Problem solving skill are very much needed in the life of the 21st century. However, it is indicated that problem solving skills with the learning model so far have not significantly improved. This study aims to improve problem-solving skills for grade 4 elementary school by using natural science learning tools based on contextual problem based learning (CPBL) on theme 2 sub-theme 3 on alternative energy that is valid, practic and effectiv. Design research was quantitative descriptive and carried out by grade IV students of SD Muhammadiyah 6 Genteng, Banyuwangi Regency involving 70 students. Research of development using a 4-D development model research design consisting of 4 stages: define, design, develop and dissemination. Processing in this study used the SPSS 17 program. After conducting research on the experimental class and control class, the data obtained from student learning outcomes in the form of pre-test and post-test data. The data will be processed using SPSS 17 to determine whether there is an effect of developing CPBL-based science learning tools on problem solving skills in class IVSD. The influence test using the independent t-test first checked the assumptions of normality and homogeneity of the pre-test and post-test data. The normality test in this study used the Shapiro-Wilk test, while the homogeneity test used the Levene test, it was found that the Sig. in the Shapiro-Wilk column for the experimental class is 0.135, because 0.135> 0.05, the pre-test data for the experimental class is normally distributed. Furthermore, the Sig value is obtained. in the Shapiro-Wilk column for the control class is 0.214, which the pre-test for the control class is also normally distributed because 0.214> 0.05. The assumption for the normality of both data is fulfilled. The analysis was carried out using a mix method, namely combining statistical data with descriptive data in the form of lesson plans, worksheets, Learning Result Test, and problem solving abilities. The results showed that all indicators were categorized as good and very good. It can be concluded that the problem solving indicators of alternative energy source materials show significant results.