bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparaison de méthodes sur un modèle de prédiction de la réussite universitaire
Authors: Vandamme Jean-Philippe , Meskens Nadine , Artiba Abdelhakim 
Published: June 2020

Depuis longtemps, l'échec scolaire en premiêre année universitaire alimente bon nombre de débats. De nombreux psychopédagogues ont tenté de le comprendre puis de l'expliquer. De nombreux statisticiens ont quant à eux essayé de le prévoir. Nos recherches visent à établir un modêle permettant de déterminer le plus tôt possible dans l'année le groupe des étudiants de premiêre année sur qui il faut cibler en priorité les ressources pédagogiques dont on dispose afin d'améliorer le taux de réussite. Pour cela, nous avons transposé sous forme de questionnaire les hypothêses posées dans de nombreux modêles théoriques. Ensuite, aprês avoir récolté via ce questionnaire des données suffisamment nombreuses et diverses, l'objectif a été d'extraire de l'information via des méthodes statistiques ou de fouille de données (data mining) et ainsi permettre la classification des étudiants en trois classes les plus homogênes possibles. Cet article décrit la méthodologie adoptée, les variables qui ont été analysées et les méthodes qui ont été utilisées et comparées. Avec la mise en parallêle des résultats fournis par les diverses méthodes (analyses discriminantes, régressions, ensembles approximatifs, arbres de décision, etc.), il est possible de mettre en lumiêre leurs différences de performance. En effet, certaines méthodes se sont montrées plus efficaces en terme de taux de prédictions correctes réalisées, là oà¹ d'autres ont surtout été intéressantes pour leur capacité à mettre en évidence les facteurs prédictifs de la réussite universitaire.
Smart Universities Walk the Talk of Commitment
Authors: VAN KEMENADE EVERARD 
Published: June 2020

Twenty first century cities encounter many problems regarding transportation, governance, information technology, environment, resources. Smart cities are needed and already booming all over the world. The concept of Smart Cities needs to be defined. The Smart City model by Giffinger et al (2007) is useful in this respect. It discerns six topics: smart living, smart governance, smart economy, smart mobility, smart environment and smart people.
This article focuses on the consequences of smart cities for universities. They can teach their students specific competences in e.g. Information Technology, Urbanisation, Smart Cities and Sustainability. They can do research in such areas. But: "The centrality of "žsmart citizens"Ÿ, rather than "žsmart cities"Ÿ, can be easily overlooked." (Slovava and Okwechime, 2016). Smart Cities can only function, if their citizen become smart. For universities that means teaching general competences to all students like problem solving, creativity, flexibility and critical thinking. Crucial is knowledge and skills regarding sustainability. For that matter, the university will need to be an example to be credible.
Actually, universities need a paradigm shift: from control and continuous improvement to commitment, a preliminary stage to real breakthrough. The stage the university is in can be measured with the Emergency Model (c) (Van Kemenade, 2017). The instrument can also point out what still needs to be done to achieve the breakthrough that is needed for universities in times of Smart Cities.
Simulation of forced oscillations of an open shell with a small attached mass, with a hinge support, by the method of Pade approximation
Authors: Добрышкин Артем Юрьевич , Сысоев Олег Евгеньевич , Сысоев Евгений Олегович , Лин Тхет 
Published: June 2020

В работе приводится уточненная математическая модель вынужденных колебаний разомкнутой оболочки с малой присоединенной массой при шарнирном опирании. Шарнирное опирание рассмотрено как наиболее часто используемое. Уравнения составлены в линейной постановке, решались асимптотическими методами, с помощью аппроксимации Паде. Проведены экспериментальные исследования, для этого изготовлены испытательный стенд, образцы, разработана программа экспериментов. Выполненное сравнение теоретических и экспериментальных данных составляет менее 5%, что говорит о высокой надежности уточненной математической модели. Полученные зависимости частоты колебаний оболочки и параметра волнообразования позволяют производить расчеты разомкнутый тонкостенных цилиндрических оболочек при параметре волнообразования больше 0,3, при проектировании таких конструкций.
The paper presents a refined mathematical model of forced oscillations of an open shell with a small attached mass at a hinge support. Hinge support is considered as the most frequently used. The equations are composed in a linear formulation, solved by asymptotic methods, using Pade approximations. Experimental studies were carried out, a test stand and samples were made for this purpose, and a program of experiments was developed. Comparison of theoretical and experimental data it is less than 5%, which indicates a high reliability of the refined mathematical model. The obtained dependences of the shell oscillation frequency and the wave formation parameter make it possible to calculate the open-ended thin-walled cylindrical shells with a wave formation parameter greater than 0.3, when designing such structures.
Elastic-plastic problem under complex shear conditions
Authors: Сенашов Сергей Иванович , Савостьянова Ирина Леонидовна 
Published: June 2020

В статье рассмотрены уравнения анизотропной теории пластического течения в пространственном случае. На основе группы непрерывных преобразований, допускаемой системой, построено инвариантное решение. В случае однородного напряженного состояния найдено новое поле скоростей. Это поле имеет функциональный произвол.
We considered the equations of the anisotropic theory of plastic flow in the spatial case in this study. We have constructed an invariant solution based on the group of continuous transformations allowed by the system. In the case of a homogeneous stress state, a new velocity field is found. This field has a functional arbitrary value.
On the question of cylindrical waves in elastic media
Authors: Алексеев Владимир Николаевич 
Published: June 2020

Рассматривается задача о распространении цилиндрической волны сжатия в упругой среде. Получены значения радиальных смещений точек среды и радиальных напряжений. Указаны асимптотические оценки полученных решений для поля смещений в среде на больших расстояниях от источников волны, а также статистическое распределение смещений среды.
The problem of propagation of a cylindrical compression wave in an elastic medium is considered. The values of radial displacements of medium points and radial stresses are obtained. Asymptotic estimates of the obtained solutions for the displacement field in the medium at large distances from the wave sources are given, as well as the statistical distribution of the displacement of the medium.
Stretching of a cylindrical rod of variable cross-section in the theory of small elastic-plastic
Authors: Петров Николай Ильич 
Published: June 2020

В работе рассматривается растяжение бесконечно длинного цилиндрического стержня переменного сечения. Используются результаты решения линеаризированных уравнений теории малых упругопластических деформаций [1-7] в случае осесимметричной задачи. Предполагается, что в начальном состоянии имеет место простое растяжение.
We considers the stretching of an infinitely long cylindrical rod of variable cross-section. The results of solving the linearized equations of the theory of small elastic-plastic deformations [1-7] in the case of an axisymmetric problem are used. It is assumed that a simple stretch occurs in the initial state.
Existence theorem for a solution of a class of third order nonlinear differential equations with polynomial right hand side of the seventh degree in a vicinity of a movable singular point
Authors: Орлов Виктор Николаевич , Гасанов Магомедюсуф Владимирович 
Published: June 2020

В настоящей статье дано развитие варианта доказательства теоремы существования и единственности решения рассматриваемого класса нелинейных дифференциальных уравнений, характерной особенностью которых является наличие подвижных особых точек. Представленное доказательство позволяет построить аналитическое приближенное решение, получить его априорные оценки. Апостериорная оценка позволяет оптимизировать априорную оценку. Теоретический материал протестирован с помощью численного эксперимента.
This article gives the development of a version of the proof of the existence and uniqueness theorem for the solution of the class of nonlinear differential equations under consideration whose characteristic feature is the presence of movable singular points. The presented proof allows us to construct an analytical approximate solution and obtain its a priori estimates. A posteriori estimation allows to optimize a priori estimation. The theoretical material is tested using a numerical experiment.
An approach of simulation of the processes of temperature stresses formation by OpenFOAM
Authors: Горшков Сергей Александрович , Дац Евгений Павлович , Мурашкин Евгений Валерьевич 
Published: June 2020

В работе предлагается реализация алгоритма расчета процесса необратимого деформирования материала в рамках теории температурных напряжений с учетом зависимости предела текучести от температуры в среде численного моделирования OpenFOAM. Рассмотрен пример решения трехмерной задачи о необратимом деформировании полого упругопластического цилиндра, подверженного нестационарному тепловому воздействию. Исследовано влияние скорости изменения теплового поля на формирование напряженнодеформированного состояния материала.
Using the OpenFOAM numerical simulation environment, an algorithm for calculating the process of irreversible material deformation is implemented within the framework of the theory of temperature stresses, taking into account the connectedness of the temperature fields and plastic deformations. The three-dimensional problem of the irreversible deformation of an elastoplastic cylinder subjected to an unsteady thermal gradient is solved. The influence of the rate of change of the thermal field on the formation of the stress-strain state of the material is investigated.
Libro de Resumenes del XXV Congreso Latinoamericano de Parasitología
Authors: Asociación Panameña de Microbiología y Parasitología * , Saldaña Azael , Álvarez Dayra 
Published: June 2020

<div id="articleFullText"><h4><span style="font-size: 1em;">Libro de resúmenes:</span></h4><a href="https://www.infomedicintl.com/resumen_flap2019/" target="_new">[Libro Digital en Línea]</a> - <a href="/index.php/rmdp/editor/downloadFile/798/1934">[Descargar el libro]</a> </div><p><span> </span></p><p>Palabras de Bienvenida</p><p>Estimados miembros y delegados de la Federación Latinoamericana de<br />Parasitología (FLAP) y amantes del fascinante mundo de la Parasitología<br />y la Microbiología:</p><p><br />Dentro del marco de celebración de nuestras fiestas patrias, Panamá se<br />vestirá de gala del 24 al 27 de noviembre del 2019 con la presencia de<br />expertos internacionales y nacionales en el campo de las ciencias<br />Microbiológicas, especialmente la Parasitología, ya que estaremos<br />celebrando el XXV Congreso FLAP, 'V Congreso de la Asociación<br />Panameña de Microbiología y Parasitología (APMyP), el XVII Congreso<br />de Estudiantes de Medicina de Panamá y XXII Jornada Cien􀀧fica.<br />Los invitamos a compartir experiencias y vivencias científicas que se<br />presentarán en charlas magistrales, simposios, talleres y carteles en<br />temas de actualidad e impacto regional que por condiciones<br />geográficas y climáticas se presentan en nuestros países.<br />Además de disfrutar de todos los atractivos que brinda nuestro querido<br />Panamá, esperamos que sea gratificante y enriquecedora su estadía.<br />Bendiciones y Bienvenidos</p><p><br />María Mireya Muñoz Arza<br />Presidenta de la FLAP y la Asociación Panameña<br />de Microbiología y Parasitología</p>
Demonstrating High-precision Photometry with a CubeSat: ASTERIA Observations of 55 Cancri e
Authors: Knapp Mary , Seager Sara , Demory Brice-Olivier , Krishnamurthy Akshata , Smith Matthew W. , Pong Christopher M. , Bailey Vanessa P. , Donner Amanda , Pasquale Peter Di , Campuzano Brian , Smith Colin , Luu Jason , Babuscia Alessandra , Bocchino, Jr. Robert L. , Loveland Jessica , Colley Cody , Gedenk Tobias , Kulkarni Tejas , Hughes Kyle , White Mary , Krajewski Joel , Fesq Lorraine 
Published: June 2020

Abstract
Arcsecond Space Telescope Enabling Research In Astrophysics (ASTERIA) is a 6U CubeSat space telescope (10 cm × 20 cm × 30 cm, 10 kg). ASTERIA’s primary mission objective was demonstrating two key technologies for reducing systematic noise in photometric observations: high-precision pointing control and high-stability thermal control. ASTERIA demonstrated 0.″5 rms pointing stability and ±10 mK thermal control of its camera payload during its primary mission, a significant improvement in pointing and thermal performance compared to other spacecraft in ASTERIA’s size and mass class. ASTERIA launched in 2017 August and deployed from the International Space Station in 2017 November. During the prime mission (2017 November–2018 February) and the first extended mission that followed (2018 March–2018 May), ASTERIA conducted opportunistic science observations, which included the collection of photometric data on 55 Cancri, a nearby exoplanetary system with a super-Earth transiting planet. The 55 Cancri data were reduced using a custom pipeline to correct complementary metal-oxide semiconductor (CMOS) detector column-dependent gain variations. A Markov Chain Monte Carlo approach was used to simultaneously detrend the photometry using a simple baseline model and fit a transit model. ASTERIA made a marginal detection of the known transiting exoplanet 55 Cancri e (∼2

), measuring a transit depth of 374 ± 170 ppm. This is the first detection of an exoplanet transit by a CubeSat. The successful detection of super-Earth 55 Cancri e demonstrates that small, inexpensive spacecraft can deliver high-precision photometric measurements.
One Planet or Two Planets? The Ultra-sensitive Extreme-magnification Microlensing Event KMT-2019-BLG-1953
Authors: Han Cheongho , Kim Doeon , Jung Youn Kil , Gould Andrew , Bond Ian A. ,   (Leading authors), Albrow Michael D. , Chung Sun-Ju , Hwang Kyu-Ha , Lee Chung-Uk , Ryu Yoon-Hyun , Shin In-Gu , Shvartzvald Yossi , Yee Jennifer C. , Zang Weicheng , Cha Sang-Mok , Kim Dong-Jin , Kim Hyoun-Woo , Kim Seung-Lee , Lee Dong-Joo , Lee Yongseok , Park Byeong-Gon , Pogge Richard W. , Kim Woong-Tae ,   (The KMTNet Collaboration), Abe Fumio , Barry Richard , Bennett David P. , Bhattacharya Aparna , Donachie Martin , Fujii Hirosane , Fukui Akihiko , Itow Yoshitaka , Hirao Yuki , Kirikawa Rintaro , Kondo Iona , Koshimoto Naoki , Li Man Cheung Alex , Matsubara Yutaka , Muraki Yasushi , Miyazaki Shota , Nagakane Masayuki , Ranc Clément , Rattenbury Nicholas J. , Satoh Yuki , Shoji Hikaru , Suematsu Haruno , Sumi Takahiro , Suzuki Daisuke , Tanaka Yuzuru , Tristram Paul J. , Yamawaki Tsubasa , Yonehara Atsunori ,   (The MOA Collaboration)
Published: June 2020

Abstract
We present the analysis of a very high-magnification (A ∼ 900) microlensing event KMT-2019-BLG-1953. A single-lens single-source (1L1S) model appears to approximately delineate the observed light curve, but the residuals from the model exhibit small but obvious deviations in the peak region. A binary-lens (2L1S) model with a mass ratio of q ∼ 2 × 10−3 improves the fits by Δχ
2 = 181.8, indicating that the lens possesses a planetary companion. From additional modeling by introducing an extra planetary lens component (3L1S model) and an extra source companion (2L2S model), it is found that the residuals from the 2L1S model further diminish, but claiming these interpretations is difficult due to the weak signals with Δχ
2 = 16.0 and 13.5 for the 3L1S and 2L2L models, respectively. From a Bayesian analysis, we estimate that the host of the planets has a mass of

and that the planetary system is located at a distance of

toward the Galactic center. The mass of the securely detected planet is

. The signal of the potential second planet could have been confirmed if the peak of the light curve had been more densely observed by follow-up observations, and thus the event illustrates the need for intensive follow-up observations for very high-magnification events even in the current generation of high-cadence surveys.
Upper Limits on Planet Occurrence around Ultracool Dwarfs with K2
Authors: Sagear Sheila A. , Skinner Julie N. , Muirhead Philip S. 
Published: June 2020

Abstract
The occurrence of planets orbiting ultracool dwarfs is poorly constrained. We present results from a guest observer program on NASA’s K2 spacecraft to search for transiting planets orbiting a sample of 827 ultracool dwarfs. Having found no transiting planets in our sample, we determined an upper limit on the occurrence of planets. We simulated planets orbiting our sample for a range of orbital periods and sizes. For the simulated planets that transit their host, we injected the transit light curve into the real K2 light curves, then attempted to recover the injected planets. For a given occurrence rate, we calculated the probability of seeing no planets, and use the results to place an upper limit on planet occurrence as a function of planet radius and orbital period. We find that short-period, mini-Neptune- and Jupiter-sized planets are rare around ultracool dwarfs, consistent with results for early- and mid-type M dwarf stars. We constrain the occurrence rate η for planets between 0.5 and 10 R
⊕ with orbital periods between 1 and 26.3 days.
Magnetic Energy Transfer and Distribution between Protons and Electrons for Alfvénic Waves at Kinetic Scales in Wavenumber Space
Authors: Duan Die , He Jiansen , Wu Honghong , Verscharen Daniel 
Published: June 2020

Abstract
Turbulent dissipation is considered a main source of heating and acceleration in cosmic plasmas. The alternating current Joule-like term,

, is used to measure the energy transfer between electromagnetic fields and particles. Because the electric field depends on the reference frame, in which frame to calculate

is an important issue. We compute the scale-dependent energy transfer rate spectrum in wavevector space, and investigate the electric-field fluctuations in two reference frames:

in the mean bulk flow frame and

in the local bulk flow frame (non-inertial reference frame). Considering Alfvénic waves, we find that

, which neglects the contribution of work done by the ion inertial force, is not consistent with the magnetic field energy damping rate (2γδB
2) according to linear Maxwell–Vlasov theory, while

is exactly the same as 2γδB
2 in wavenumber space (k
∥, k
⊥), where γ is the linear damping rate. Under typical conditions of solar wind at 1 au, we find in our theoretical calculation that the field energy is mainly converted into proton kinetic energy leaving the residual minor portion for electrons. Although the electrons gain energy in the direction perpendicular to the mean magnetic field, they return a significant fraction of their kinetic energy in the parallel direction. Magnetic-field fluctuations can transfer particle energy between the parallel and perpendicular degrees of freedom. Therefore,

and

do not solely describe the energy transfer in the parallel direction and perpendicular direction, respectively.
Physical Model of Dust Polarization by Radiative Torque Alignment and Disruption and Implications for Grain Internal Structures
Authors: Lee Hyeseung , Hoang Thiem , Le Ngan , Cho Jungyeon 
Published: June 2020

Abstract
Dust polarization depends on mechanical properties of dust as well as on local environments. To understand how dust polarization varies with different properties, we model the wavelength-dependence polarization of starlight and polarized dust emission of aligned grains by simultaneously taking into account grain alignment and rotational disruption by radiative torques (RATs). We explore a wide range of the local radiation field and grain mechanical properties characterized by tensile strength (S
max). We find that the peak wavelength shifts to shorter wavelengths as the radiation strength (U) increases due to the enhanced alignment of small grains. Grain rotational disruption by RATs tends to decrease the optical-NIR polarization but increase the UV polarization of starlight due to the conversion of large grains into smaller ones. In particular, we find that the polarization degree at 850 μm (P
850) does not increase monotonically with U or grain temperature (T

d
), but it depends on S
max of the grains. Our model can be tested with observations toward star-forming regions or molecular clouds irradiated by a nearby star, which have higher radiation intensities than the that of the average interstellar radiation field. Finally, we compare our predictions of the P
850–T

d
relationship with Planck data and find that the observed decrease of P
850 with T

d
can be explained when grain disruption by RATs is accounted for, suggesting that as interstellar grains are unlikely to have a compact structure, perhaps they have a composite one. The variation of the polarization degree with U (or T

d
) can provide a valuable constraint on the internal structure of cosmic dust.
The Second Plateau in X-Ray Afterglow Providing Additional Evidence for Rapidly Spinning Magnetars as the GRB Central Engine
Authors: Zhao Litao , Liu Liangduan , Gao He , Lan Lin , Lei WeiHua , Xie Wei 
Published: June 2020

Abstract
Evidence for the central engine of gamma-ray bursts (GRBs) has been collected in the Neil Gehrels Swift data. For instance, some GRBs show an internal X-ray plateau followed by very steep decay, which is difficult interpret within the framework of a black hole (BH) central engine, but is consistent within a rapidly spinning magnetar engine picture. The very steep decay at the end of the plateau suggests a sudden cessation of the central engine, which is explained as the collapse of a supramassive magnetar into a BH when it spins down. Here we propose that some additional evidence, such as a second X-ray plateau feature, would show up if the fallback accretion could activate the newborn BH and sufficient energy could be transferred from the newborn BH to the GRB blast wave. With a systematic data analysis for all long GRBs, we find three candidates in the Swift sample, i.e., GRBs 070802, 090111, and 120213A, whose X-ray afterglow lightcurves contain two plateaus, with the first one being an internal plateau. We find that in a fairly loose and reasonable parameter space, the second X-ray plateau data for all 3 GRBs could be interpreted with our proposed model. Future observations are likely to discover similar events, which could offer more information on the properties of the magnetar, as well as the newborn BH.