bluuebunny/crossref_metadata_2025 huggingface dataset:
AVALIAÇÃO DO RISCO DE MORTALIDADE NEONATAL NA APLICAÇÃO DO ESCORE CRIB
Authors: VIEIRA CARLA AMARAL , AFIUNE SANDRA MARCIA RAMOS PIMENTEL , PORTAL DANIELA CARVALHO , MIGUEL PATRÍCIA DE PAULA , SAIDAH TÁRIK KASSEM
Published: March 2021

INTRODUÇÃO: Em neonatologia, vários escores de gravidade da doença foram desenvolvidos para prever o risco de mortalidade e morbidade em neonatos. Dentre os escores baseados em alterações fisiológicas, alguns são mais simples, com poucas variáveis e de aplicação rápida; outros são mais completos, pois contemplam mais variáveis, mas demoram mais para serem aplicados. Os sistemas de pontuação mais estudados e mais utilizados em recém-nascidos são o Índice de Risco Clínico para Bebês (CRIB) e o Escore de Fisiologia Aguda Neonatal (SNAP). Essas pontuações foram validadas e reaplicadas em estudos distintos em diferentes. O sistema de pontuação neonatal CRIB (índice de risco clínico para bebês) utiliza peso ao nascer, idade gestacional, fração máxima e mínima de oxigênio inspirado e excesso máximo de base nas primeiras 12 horas e presença de malformações congênitasOBJETIVO: Determinar a taxa de mortalidade dos recém-nascidos com as variações do CRIB. RESULTADOS: Dos 283 recém-nascidos internados, 62 preencheram os critérios de inclusão. A coorte analisada apresentou peso médio de nascimento de 834,84g e variação de 500 a 1415 g. A idade gestacional média foi de 27 semanas variando de 23,3 a 31 semanas. O escore médio do CRIB foi de 6,8 e variação de 1 a 14. Foram a óbito 29 recém-nascidos (46,7%). A coorte analisada apresentou peso médio de nascimento de 834,84g e variação de 500 a 1415 g. A idade gestacional média foi de 27 semanas variando de 23,3 a 31 semanas. O escore médio do CRIB foi de 6,8 e variação de 1 a 14. A taxa de mortalidade foi observada com maior frequência em recém-nascidos com peso entre 751g a 999 gramas, idade gestacional entre 22 a 28 semanas e escore CRIB acima de 6 a 10. A taxa de sobrevida foi observada com maior frequência em recém-nascidos com peso entre 751g a 999 gramas, idade gestacional entre 22 a 28 semanas e escore CRIB acima de 0 a 5. CONCLUSÕES: O escore médio do CRIB foi de 6,8 e variação de 1 a 14. Foram a óbito 29 recém-nascidos (46,7%). A taxa de mortalidade foi observada com maior frequência em recém-nascidos com peso entre a 751g a 999 gramas, idade gestacional entre 22 a 28 semanas e escore CRIB acima de 6 a 10. A taxa de sobrevida foi observada com maior frequência em recém-nascidos com peso entre 751g a 999 gramas, idade gestacional entre 22 a 28 semanas e escore CRIB acima de 0 a 5.
SÍNDROME DA ARTÉRIA MESENTÉRICA SUPERIOR – SÍNDROME DE WILKIE: RELATO DE DOIS CASOS
Authors: SILVA RÔMULO MENDES , LINHARES LOHANA MENDONÇA , EDUARDO NATÁLLIA ROSA , MENDONÇA ISABELA COUTO , CANEDO RAPHAEL SALES NOGUEIRA AMORIM
Published: March 2021

Introdução: Síndrome da Artéria Mesentérica Superior/Síndrome de Wilkie Caracteriza-se pela compressão da terceira porção do duodeno, devido a redução da angulação da aorta com a artéria mesentérica superior. Enfermidade rara, com poucos casos descritos na literatura médica. Caso 01: Paciente 13 anos, sexo masculino, com diagnóstico de Anemia de Blackfan-Diamond e quadro de oclusão intestinal aguda há 2 dias com episódios prévios recorrentes de oclusão intestinal. TC evidenciando gastrectasia e dilatação de alças de delgado até a terceira porção de duodeno. Caso 02: Paciente de 18 anos, sexo feminino, sem comorbidades prévias, com quadro de obstrução intestinal alta há 7 dias, com TC evidenciando obstrução duodenal e redução da angulação aorto-mesentérica. Discussão: A faixa etária de maior prevalência ocorre entre 18 e 35 anos. Associada principalmente à perda ponderal e Síndrome Cast. O diagnóstico por suspeição clínica confirmado com REED ou TC contrastada de abdome. O tratamento pode ser conservador com medidas de ganho ponderal ou cirúrgico, sendo a duodenojejunoanastomose a técnica de escolha. Anemia de Blackfan-Diamond apesar de estar relacionada com alterações estaturo-ponderais não foi identificada associação na literatura médica com a Síndrome de Wilkie. Conclusão: O diagnóstico diferencial deve ser aventado em pacientes jovens com vômitos de repetição. A EDA pode atrasar o diagnóstico.
Test means for separate and total determination of heavy metals in aqueous media
Authors:   Saratov State University, Gabidulina Marina K. , Doronin Sergey Yu. ,   Saratov State University, Kosyreva Irina V. ,   Saratov State University
Published: March 2021

The classification of the main indicators of the quality of water bodies is considered. The data on controlled chemical indicators are given (content of dissolved oxygen, suspended solids, phenols, petroleum products, etc.) A list of priority hydrochemical water pollutants and the sources of their pollution are presented. The expediency of determining both individual ions of heavy metals (HM) and their complex (integral) indicators is shown by the example of the sum of HMs. The authors summarized existing data on contemporary test methods used for detection and quantitative measurement of the most prominent HM pollutants of aqueous media, namely – Fe(II), Fe(III), Co(II), Ni(II), Cu(II), Mn(II) and Al(III) ions. Concentration of such HM ions can be evaluated by various test means such as indicator papers, detector tubes and polymer plates etc. The main matrices of the test means are considered: cellulose papers, fabrics from artificial and natural fibers, silica gels, xerogels, polymeric materials, etc. The conditions for immobilization and modification of test means (carrying agent, reagent, surfactant, etc.) and principles of analyte determination using the developed test tools (visual and instrumental assessment of the intensity of staining of test forms, determination of the length of staining or bleaching of test tube zones, etc.), as well as some metrological characteristics (detection limit, range of determined contents, relative errors of definitions, etc.) are shown in this article. Detection limits of studied heavy metal ions in aqueous media that can be achieved with proposed test means are as follows: Fe(II) – (0.005-0.01) mg/l; Fe(III) – 0.1 mg/l; Co(II) – (0.02-0.4) mg/l; Ni(II) – (0.1-10) mg/l; Cu(II) – 0.05 mg/l; Mn(II) – 0.03 mg/l; Al(III) – 0.02 mg/l; total concentration of several HM ions – (0.0005-0.001) mg/l.
Phase composition and microstructure of Mo-Si-V hypoeutectic alloys obtained under non-equilibrium crystallization conditions
Authors:   Institute of Metallurgy of Ural Branch of Russian Academy of Sciences, Larionov Alexey V. , Pikulin Kirill V. ,   Institute of Metallurgy of Ural Branch of Russian Academy of Sciences, Chumarev Vladimir M. ,   Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences, Udoeva Lyudmila Y. ,   Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences, Smirnov Leonid A. ,   Institute of Metallurgy of Ural Branch of Russian Academy of Sciences
Published: March 2021

The phase composition, microstructure are investigated and the densities of Mo-15.3Si (at. %) hypoeutectic alloys alloyed with vanadium are determined. The main phase components of the alloys and their volumetric contents were determined by X-ray phase analysis (XRD) and X-ray microanalysis (RSMA) methods. The unit cell parameters of the main phases of Mo-Si-V alloys are calculated. It is shown that with the introduction of up to 20.0 at. % of vanadium into the hypoeutectic alloy Mo-15.3Si, a structure is formed consisting of two solid solutions: (Mo,V)ss with silicon dissolved in it (up to 5.0 at. %) and (Mo,V)3Si with a silicon deficiency of about 4.0 at. % trelative to the stoichiometric composition. With an increase in the content of vanadium in alloys, the volume ratio of the metal component to the silicide ratio almost doubles. At the same time, the microhardness of the metal phase increases 1.5 times and reaches 887 HV, and the microhardness of silicide, on the contrary, decreases by 1.2 times and is 1057 HV. The dependences of the microhardness of the structural components of the alloys, as well as the parameters of their crystal lattices on the concentration of the alloying element in them, are consistent with the concepts of the formation of substitution solid solutions, both in the metal and in the silicide phases. The introduction of 20.0 at. % of vanadium into the Mo-15.3Si hypoeutectic alloy reduces its density, and, therefore, the mass of the alloy by 10.5% from 9.49 to 8.49 g/cm3.
The study of the microstructure and mechanical properties of low carbon steel, microalloying by boron
Authors:   Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences, Babenko Anatoly A. , Selmensky Natalia I. ,   Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences, Upolovnikova Alena G. ,   Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences
Published: March 2021

The paper presents the results of the study of non-metallic inclusions, the structure and mechanical properties of low carbon steel, microalloying by boron. The study of the amount and composition of nonmetallic inclusions showed that with the introduction of boron the volume fraction of oxide and oxysulfide inclusions increases and the volume fraction of sulfide inclusions significantly decreases. At the same time, the alloying of steel with boron increases to 99.7% the proportion of inclusions with a size of no more than 5 microns against 80.6% in the metal without boron. In the metal with boron, nonmetallic inclusions larger than 10 μm are absent, while in the metal without boron their share is 13.6%. Studies have shown that in a metal containing 0.011% boron, independent boron-containing inclusions were not detected. Boron was not detected in the composition of the studied nonmetallic inclusions. In all samples, steel nonmetallic inclusions are represented mainly by oxide, oxysulfide and sulfide inclusions. In the boron-free steel, a small amount of perlite is present along with the ferritic phase. Steel microalloying by boron is accompanied by the formation of a dispersed ferrite-bainite structure, which consists of fine-grained ferrite with bainite sites with a tendency to form bainite strips along the rolling direction. The microhardness of ferrite and perlite in steel without boron does not exceed an average of 180 and 214 HV10, respectively. It is noted that the presence of boron in steel in an amount of 0.011% increases the microhardness of ferrite to 260 HV10 and bainite to 335 HV10. The mechanical properties of hot-rolled steel with a thickness of 10 mm from boron-containing low-alloyed steel, due to the predominant formation of small rounded inclusions with a size of no more than 5 microns and the formation of a fine ferrite-bainite structure, are characterized by enhanced strength properties with preservation of plastic characteristics. The absolute values of the yield strength and temporary resistance of steel with boron reach 575 and 650 MPa, respectively. With such strength properties of metal, high plastic characteristics are preserved. Rolled steel without boron is characterized by reduced to 540 and 610 MPa tensile strength and temporary resistance, respectively.
Properties of filamentary nanocrystals of cadmium sulfide synthesized by vacuum evaporation and condensation
Authors:   St. Petersburg State Chemical-Pharmaceutical  University, Belyaev Alexey P. , Rubetz Vladimir P. ,   St Petersburg State Institute of Technology (Technical University), Antipov Vladimir V. ,   St Petersburg State Institute of Technology (Technical University)
Published: March 2021

In recent decades, 1D structures, such as Nano whiskers, nanowires, Nano rods, etc., have attracted considerable interest of researcher due to their highly promising application in electronics, photonics, energy conversion and storage systems, medicine and pharmacology, and in modeling interaction with biomolecules and living calls. A prominent place among nanostructures is occupied by 1D nanostructures grown perpendicular to the substrate surface. These nanostructures are called Nano whiskers. Below reported about physicochemical studies of the ensemble of filamentary nanocrystals of cadmium sulfide synthesized by vacuum evaporation and condensation. It is presented the results of technological experiments, the results of electronic microscopy and the results of electron diffraction studies. It is shown that by means of vacuum evaporation and condensation it is possible to synthesize filamentary nanocrystals of diameter from 10 nm to few µm and of the length of few mm. It is revealed technological conditions necessary for the synthesis of filamentary nanocrystals. It is determined relation between growth rate of filamentary nanocrystals and their linear characteristics. It is shown that mechanism of growth of nanocrystals synthesized by used method is in full accordance with model views of classical mechanism vapor-liquid-crystal of Givargizov-Chernov. For revealing of crystalline perfection of filamentary nanocrystals it is used electron diffraction method, at so doing for increasing of the level of analytical signal it is used superposition of diffraction patterns from ensemble of filamentary nanocrystals. The method proposed permitted establish high degree of perfection of filamentary nanocrystals synthesized by vacuum evaporation and condensation.
Conversion of pentane-hexane fraction on the Zr-containing catalyst systems
Authors:   N.G. Chernyshevsky Saratov National Research State University, Gritsienko Alexey A. , Annenkov Ilya Sergeevich ,   N.G. Chernyshevsky Saratov National Research State University, Aniskova Tatiana V. ,   N.G. Chernyshevsky Saratov National Research State University
Published: March 2021

The tightening environmental standards for motor fuels on the one hand and the rapid growth of high quality motor fuel consumption on the other hand poses the problem of refining to reduce the amount of aromatics and in particular benzene in commercial products. Currently recycling oil is essential to the overall petroleum refining complex. To increase the depth of processing, and most important for the production of high octane components of motor fuels meeting the Euro-5 requirements, different processing variants hydrotreated fractions, among which the most modern process is isomerization. And because of this isomerization – as a process of producing components of gasoline with a high octane number and a low aromatic content became widespread. This work is devoted to the research activity of the two catalyst systems containing zirconium in its composition, in the conversion of pentane-hexane fraction, which is the raw material of isomerization process in refineries. The study was conducted in a laboratory flow-type reactor with a fixed catalyst bed. Analysis of the gaseous and liquid products of transformation was performed by gas-liquid chromatography. On the basis of analysis of experimental data, we can conclude that the two systems studied most active catalyst in the isomerization of pentane-hexane fraction is a system based on zeolite. When used which is possible to obtain liquid products with a low content of unbranched alkanes and high in isoparaffins that have high octane numbers and are safe components of motor fuels from an environmental point of view.
The Differential Geometry of the Orbit Space of Extended Affine Jacobi Group A1
Authors:   SISSA, Italy, Almeida Guilherme F.
Published: March 2021

We define certain extensions of Jacobi groups of A1, prove an analogue of Chevalley theorem for their invariants, and construct a Dubrovin-Frobenius structure on its orbit space.
TESS Hunt for Young and Maturing Exoplanets (THYME). V. A Sub-Neptune Transiting a Young Star in a Newly Discovered 250 Myr Association
Authors: Tofflemire Benjamin M. , Rizzuto Aaron C. , Newton Elisabeth R. , Kraus Adam L. , Mann Andrew W. , Vanderburg Andrew , Nelson Tyler , Hawkins Keith , Wood Mackenna L. , Zhou George , Quinn Samuel N. , Howell Steve B. , Collins Karen A. , Schwarz Richard P. , Stassun Keivan G. , Bouma Luke G. , Essack Zahra , Osborn Hugh , Boyd Patricia T. , Fűrész Gábor , Glidden Ana , Twicken Joseph D. , Wohler Bill , McLean Brian , Ricker George R. , Vanderspek Roland , Latham David W. , Seager S. , Winn Joshua N. , Jenkins Jon M.
Published: March 2021

The detection and characterization of young planetary systems offer a direct path to study the processes that shape planet evolution. We report on the discovery of a sub-Neptune-sized planet orbiting the young star HD 110082 (TOI-1098). Transit events we initially detected during TESS Cycle 1 are validated with time-series photometry from Spitzer. High-contrast imaging and high-resolution, optical spectra are also obtained to characterize the stellar host and confirm the planetary nature of the transits. The host star is a late-F dwarf (M
⋆ = 1.2M
⊙) with a low-mass, M dwarf binary companion (M
⋆ = 0.26M
⊙) separated by nearly one arcminute (∼6200 au). Based on its rapid rotation and Lithium absorption, HD 110082 is young, but is not a member of any known group of young stars (despite proximity to the Octans association). To measure the age of the system, we search for coeval, phase-space neighbors and compile a sample of candidate siblings to compare with the empirical sequences of young clusters and to apply quantitative age-dating techniques. In doing so, we find that HD 110082 resides in a new young stellar association we designate MELANGE-1, with an age of

Myr. Jointly modeling the TESS and Spitzer light curves, we measure a planetary orbital period of 10.1827 days and radius of R

p
= 3.2 ± 0.1R
⊕. HD 110082 b’s radius falls in the largest 12% of field-age systems with similar host-star mass and orbital period. This finding supports previous studies indicating that young planets have larger radii than their field-age counterparts.
Formation of “Blanets” from Dust Grains around the Supermassive Black Holes in Galaxies
Authors: Wada Keiichi , Tsukamoto Yusuke , Kokubo Eiichiro
Published: March 2021

In Wada et al. (2019), we proposed for the first time that a new class of planets, blanets, can be formed around supermassive black holes in the galactic center. Here, we investigate the dust coagulation processes and physical conditions of the blanet formation outside the snowline (r
snow ∼ several parsecs) in more detail, especially considering the effect of the radial drift of the dust aggregates. We found that a dimensionless parameter

, where v

t
is the turbulent velocity and c

s
is the sound velocity, describing the turbulent viscosity should be smaller than 0.04 in the circumnuclear disk to prevent the destruction of the aggregates due to collision. The formation timescale of blanets τ
GI at r
snow is, τ
GI ≃ 70–80 Myr for α = 0.01 − 0.04 and M
BH = 106
M
⊙. The mass of the blanets ranges from ∼20M

E
to 3000M

E
in r < 4 pc for α = 0.02 (M

E
is the Earth mass), which is in contrast with 4M
E–6M
E for the case without the radial drift. Our results suggest that blanets could be formed around relatively low-luminosity active galactic nuclei (L
bol ∼ 1042 erg s−1) during their lifetime (≲108 yr).
Switchbacks Explained: Super-Parker Fields—The Other Side of the Sub-Parker Spiral
Authors: Schwadron N. A. , McComas D. J.
Published: March 2021

We provide a simple geometric explanation for the source of switchbacks and associated large and one-sided transverse flows in the solar wind observed by the Parker Solar Probe (PSP). The more radial, sub-Parker spiral structure of the heliospheric magnetic field observed previously by Ulysses, ACE, and STEREO is created within rarefaction regions where footpoint motion from the source of fast into slow wind at the Sun creates a magnetic fieldline connection across solar wind speed shear. Conversely, when footpoints move from the source of slow wind into faster wind, a super-Parker spiral field structure is formed: below the Alfvén critical point, one-sided transverse field-aligned flows develop; above the Alfvén critical point, the field structure contracts between adjacent solar wind flows, and the radial field component decreases in magnitude with distance from the Sun, eventually reversing into a switchback. The sub-Parker and super-Parker spirals behave functionally as opposites. Observations from PSP confirm the paucity of switchbacks within rarefaction regions and immediately outside these rarefaction regions, we observe numerous switchbacks in the magnetic field that are directly associated with abrupt transients in solar wind speed. The magnetic field strength, the radial component of the magnetic field, the speed gradients, radial Alfvén speed, and the ratio of the sound speed to the radial Alfvén speed all conform to predictions based on the sub-Parker and super-Parker spirals within rarefaction regions and solar wind speed enhancements (spikes or jets), respectively. Critically, the predictions associated with the super-Parker spiral naturally explain the observations of switchbacks being associated with unexpectedly large and one-sided tangential flows.
Lyman Continuum Emission Escaping from Luminous Green Pea Galaxies at z = 0.5
Authors: Malkan Matthew A. , Malkan Brian K.
Published: March 2021

Compact starburst galaxies are thought to include many or most of the galaxies from which substantial Lyman continuum emission can escape into the intergalactic medium. Li & Malkan used Sloan Digital Sky Survey photometry to find a population of such starburst galaxies at z ∼ 0.5. They were discovered by their extremely strong [O iii] λλ4959+5007 emission lines, which produce a clearly detectable excess brightness in the i bandpass, compared with surrounding filters. We therefore used the Hubble Space Telescope (HST)/COS spectrograph to observe two of the newly discovered i-band excess galaxies around their Lyman limits. One has strongly detected continuum below its Lyman limit, corresponding to a relative escape fraction of ionizing photons of 20% ± 2%. The other, which is less compact in UV imaging, has a 2σ upper limit to its Lyman escape fraction of <5%. Before the UV spectroscopy, the existing data could not distinguish these two galaxies. Although a sample of two is hardly sufficient for statistical analysis, it shows the possibility that some fraction of these strong [O iii] emitters as a class have ionizing photons escaping. The differences might be determined by the luck of our particular viewing geometry. Obtaining the HST spectroscopy revealed that the Lyman-continuum-emitting galaxy differs in having no central absorption in its prominent Lyα emission-line profile. The other target, with no escaping Lyman continuum, shows the more common double-peaked Lyα emission.
First Phase Space Portrait of a Hierarchical Stellar Structure in the Milky Way
Authors: Dalessandro Emanuele , Varri A. L. , Tiongco M. , Vesperini E. , Fanelli C. , Mucciarelli A. , Origlia L. , Bellazzini M. , Saracino S. , Oliva E. , Sanna N. , Fabrizio M. , Livernois A.
Published: March 2021

We present the first detailed observational picture of a possible ongoing massive cluster hierarchical assembly in the Galactic disk as revealed by the analysis of the stellar full phase space (3D positions and kinematics and spectro-photometric properties) of an extended area (6° diameter) surrounding the well-known h and χ Persei double stellar cluster in the Perseus Arm. Gaia-EDR3 shows that the area is populated by seven comoving clusters, three of which were previously unknown, and by an extended and quite massive (M ∼ 105
M
⊙) halo. All stars and clusters define a complex structure with evidence of possible mutual interactions in the form of intra-cluster overdensities and/or bridges. They share the same chemical abundances (half-solar metallicity) and age (t ∼ 20 Myr) within a small confidence interval and the stellar density distribution of the surrounding diffuse stellar halo resembles that of a cluster-like stellar system. The combination of these pieces of evidence suggests that stars distributed within a few degrees from h and χ Persei are part of a common, substructured stellar complex that we named LISCA I. Comparison with results obtained through direct N-body simulations suggest that LISCA I may be at an intermediate stage of an ongoing cluster assembly that can eventually evolve in a relatively massive (a few times 105
M
⊙) stellar system. We argue that such a cluster formation mechanism may be quite efficient in the Milky Way and disk-like galaxies and, as a consequence, it has a relevant impact on our understanding of cluster formation efficiency as a function of the environment and redshift.
Coronal Heating Law Constrained by Microwave Gyroresonant Emission
Authors: Fleishman Gregory D. , Anfinogentov Sergey A. , Stupishin Alexey G. , Kuznetsov Alexey A. , Nita Gelu M.
Published: March 2021

The question why the solar corona is much hotter than the visible solar surface still puzzles solar researchers. Most theories of the coronal heating involve a tight coupling between the coronal magnetic field and the associated thermal structure. This coupling is based on two facts: (i) the magnetic field is the main source of the energy in the corona and (ii) the heat transfer preferentially happens along the magnetic field, while is suppressed across it. However, most of the information about the coronal heating is derived from the analysis of extreme ultraviolet or soft X-ray emissions, which are not explicitly sensitive to the magnetic field. This paper employs another electromagnetic channel—the sunspot-associated microwave gyroresonant emission, which is explicitly sensitive to both the magnetic field and thermal plasma. We use nonlinear force-free field reconstructions of the magnetic skeleton dressed with a thermal structure as prescribed by a field-aligned hydrodynamics to constrain the coronal heating model. We demonstrate that the microwave gyroresonant emission is extraordinarily sensitive to details of the coronal heating. We infer heating model parameters consistent with observations.
Migration of Solar Polar Crown Filaments in the Past 100 Years
Authors: Xu Yan , Banerjee Dipankar , Chatterjee Subhamoy , Pötzi Werner , Wang Ziran , Ruan Xindi , Jing Ju , Wang Haimin
Published: March 2021

Polar crown filaments (PCFs) are formed above the polarity inversion line, which separates unipolar polar fields and the nearest dispersed fields. They are important features in studying solar polar fields and their cyclical variations. Due to the relatively weak field strength and projection effects, measuring polar magnetic fields is more difficult than obtaining the field strengths concentrated in active regions at lower latitudes. “Rush-to-the-pole” of PCFs represent the progress of unipolar polar fields from the previous solar cycle being canceled by the dispersed fields generated in the current cycle. Such progress is a good indicator of the polarity reversal in the polar areas and a precursor for the solar maximum. In this study, PCFs are identified from a 100 yr archive, covering cycles 16–24. This archive consists of full-disk Hα images obtained from the Kodaikanal Solar Observatory of the Indian Institute of Astrophysics, Kanzelhöhe Solar Observatory, and Big Bear Solar Observatory. The poleward migration speeds are measured and show an obvious asymmetry in the northern and southern hemispheres. In addition, our results show that the PCFs usually reach their highest latitudes first in the northern hemisphere, except cycle 17. Similarly, previous studies show that the magnetic field reversed first at the north pole in six out of nine cycles. We also compare the temporal variations of PCF migration and the latitude gradient factor of the differential rotation, which shows a trend in the southern hemisphere. Moreover, the migration speed of PCFs does not seem to be well correlated with the maximum sunspot numbers.
Possible Periodic Activity in the Short Bursts of SGR 1806-20: Connection to Fast Radio Bursts
Authors: Zhang G. Q. , Tu Zuo-Lin , Wang F. Y.
Published: March 2021

Magnetars are highly magnetized neutron stars that are characterized by recurrent emission of short-duration bursts in soft gamma-rays/hard X-rays. Recently, FRB 200428 was found to be associated with an X-ray burst from a Galactic magnetar. Two fast radio bursts show mysterious periodic activity. However, it is unclear whether magnetar X-ray bursts are periodic phenomena. In this paper, we investigate the activity period of SGR 1806-20. More than 3000 short bursts observed by different telescopes are collected, including the observations of RXTE, HETE-2, ICE, and Konus. We consider the observation windows and divide the data into two subsamples to alleviate the effect of uneven sampling. The epoch-folding and Lomb–Scargle methods are used to derive the period of the short bursts. We find a possible period of about 398.20 ± 25.45 days, but other peaks exist in the periodograms. If the period is real, the connection between short bursts of magnetars and fast radio bursts should be investigated extensively.
Slow Cooling and Fast Reinflation for Hot Jupiters
Authors: Thorngren Daniel P. , Fortney Jonathan J. , Lopez Eric D. , Berger Travis A. , Huber Daniel
Published: March 2021

The unexpectedly large radii of hot Jupiters are a longstanding mystery whose solution will provide important insights into their interior physics. Many potential solutions have been suggested, which make diverse predictions about the details of inflation. In particular, although any valid model must allow for maintaining large planetary radii, only some allow for radii to increase with time. This reinflation process would potentially occur when the incident flux on the planet is increased. In this work, we examine the observed population of hot Jupiters to see if they grow as their parent stars brighten along the main sequence. We consider the relation between radius and other observables, including mass, incident flux, age, and fractional age (age over main-sequence lifetime), and show that main-sequence brightening is often sufficient to produce detectable reinflation. We further argue that these provide strong evidence for the relatively rapid reinflation of giant planets, and discuss the implications for proposed heating mechanisms. In our population analysis we also find evidence for a “delayed cooling effect,” wherein planets cool and contract far more slowly than expected. While not capable of explaining the observed radii alone, it may represent an important component of the effect. Finally, we identify a weak negative relationship between stellar metallicity and planet radius that is presumably the result of enhanced planetary bulk metallicity around metal-rich stars and has important implications for planet formation theory.
La transparence des politiques de renseignement : une tentative d’évaluation à l’échelle européenne
Authors: Sciences Po/PSIA
Published: March 2021

Les politiques de renseignement sont très variables d’un pays à l’autre, en particulier leur transparence et leur système de contrôle par les citoyens. D’où ce projet d’évaluation à l’échelle européenne avec des critères d’analyse permettant de saisir les bonnes pratiques dans des États revendiquant leur caractère démocratique.
Le Golfe : le mirage des possibles
Authors: Tribot La Spière Loic , Benabderrahmane Tayeb
Published: March 2021

Le Golfe, région en crise quasi permanente, pourrait entrevoir de nouvelles perspectives plus positives, à l’aune des mutations imposées par les évolutions géopolitiques dont la pandémie de la Covid-19. Certes, les tensions subsistent mais des changements pourraient être possibles.
Histoire militaire
Authors: Franc Claude
Published: March 2021

La IV e  République hérite d’une marine en piteux état après une guerre dévastatrice. La reconstruction de l’outil naval a été complexe et a bénéficié, à partir de 1962, de l’aide américaine. L’amiral Nomy, chef d’état-major de la Marine de 1951 à 1960, y a joué un rôle essentiel, préparant la Marine de la V e  République.
A Comparison of Surgical and Conservative Treatment in Ankle Ligament Tears
Authors: Specchiulli Franco , Cofano R E
Published: March 2021

Good results have been reported after both primary repair and conservative management of grade III ankle sprains. This prospective study found no advantage of operative treatment compared to taping; no significant differences were found between the groups with regard to objective or subjective stability, functional scores, or the overall result.
Electrostatic features for nucleocapsid proteins of SARS-CoV and SARS-CoV-2
Authors: Guo Wenhan , Xie Yixin , Lopez-Hernandez Alan E , Sun Shengjie , Li Lin
Published: March 2021

COVID-19 is increasingly affecting human health and global economy. Understanding the fundamental mechanisms of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) is highly demanded to develop treatments for COVID-19. SARS-CoV and SARS-CoV-2 share 92.06% identity in their N protein RBDs' sequences, which results in very similar structures. However, the SARS-CoV-2 is more easily to spread. Utilizing multi-scale computational approaches, this work studied the fundamental mechanisms of the nucleocapsid (N) proteins of SARS-CoV and SARS-CoV-2, including their stabilities and binding strengths with RNAs at different pH values. Electrostatic potential on the surfaces of N proteins show that both the N proteins of SARS-CoV and SARS-CoV-2 have dominantly positive potential to attract RNAs. The binding forces between SARS-CoV N protein and RNAs at different distances are similar to that of SARS-CoV-2, both in directions and magnitudes. The electric filed lines between N proteins and RNAs are also similar for both SARS-CoV and SARS-CoV-2. The folding energy and binding energy dependence on pH revealed that the best environment for N proteins to perform their functions with RNAs is the weak acidic environment.
Optimal control of the transmission rate in compartmental epidemics
Authors: Freddi Lorenzo
Published: March 2021

We introduce a general system of ordinary differential equations that includes some classical and recent models for the epidemic spread in a closed population without vital dynamic in a finite time horizon. The model is vectorial, in the sense that it accounts for a vector valued state function whose components represent various kinds of exposed/infected subpopulations, with a corresponding vector of control functions possibly different for any subpopulation. In the general setting, we prove well-posedness and positivity of the initial value problem for the system of state equations and the existence of solutions to the optimal control problem of the coefficients of the nonlinear part of the system, under a very general cost functional. We also prove the uniqueness of the optimal solution for a small time horizon when the cost is superlinear in all control variables with possibly different exponents in the interval \begin{document}$ (1,2] $\end{document}. We consider then a linear cost in the control variables and study the singular arcs. Full details are given in the case \begin{document}$ n = 1 $\end{document} and the results are illustrated by the aid of some numerical simulations.
Self-healing concrete-What Is it Good For?
Authors: Roig-Flores M. , Formagini S. , Serna P.
Published: March 2021

Self-healing of concrete is the process in which the material regenerates itself repairing inner cracks. This process can be produced by autogenous or autonomous healing. Autogenous healing is a natural process, produced by carbonation and/or continuing hydration. Autonomous healing is based on the use of specific agents to produce self-healing, which can be added directly to the concrete matrix, embedded in capsules or introduced through vascular networks. Some examples are superabsorbent polymers, crystalline admixtures, microencapsulated sodium silicate, and bacteria. This review is structured into two parts. The first part is an overview of self-healing concrete that summarises the basic concepts and the main advances produced in the last years. The second part is a critical discussion on the feasibility of self-healing concrete, its possibilities, current weaknesses, and challenges that need to be addressed in the coming years.
Modeling of the Function Principle of Semiconductor Gas Sensors for High School Students
Authors: Höfner Sebastian , Hirth Michael , Kuhn Jochen , Brück Benjamin , Schütze Andreas
Published: March 2021

A wide range of pollutants cannot be perceived with human senses, which is why theuse of gas sensors is indispensable for an objective assessment of air quality. Sincemany pollutants are both odorless and colorless, there is a lack of awareness, inparticular among high school students. The project SUSmobil (funded by DBU –Deutsche Bundesstiftung Umwelt) aims to change this. In three modules on the topic ofgas sensors and air quality, the students (1) are familiarized with the functionality of ametal oxide semiconductor (MOS) gas sensor, (2) perform a sensor calibration and (3)carry out environmental measurements with calibrated sensors. Based on theseintroductory experiments, the students are encouraged to develop their ownenvironmental questions. In this contribution, we focus on the experimental andmodeling approach which explains the function principle of a MOS gas sensor in a waysuitable for high school students. This includes a qualitative and quantitativedescription of a simplified sensor model explaining the main processes on the sensorsurface. In addition, an HTML-based self-learning course is presented in which thestudents investigate the sensor behavior in the presence of different substancesdepending on the sensor temperature.
Optimization Research and Exploration of New Rural Cooperative Medical Information System
Authors: Zhang Guohua
Published: March 2021

The New Rural Cooperative Medical Care Information System (NRCMS) used a single relational database to store most of the data in the early days. The scheme is difficult to expand and has little concurrent ability, so it is not suitable to deal with semi-structured, Unstructured data. Then along came distributed technologies such as Hadoop, which had the advantage of using inexpensive machines to store and process data. But HADOOP was designed to distribute data equally among the nodes in the cluster for storage and processing, ignoring the differences in the storage and computing capabilities of the cluster nodes themselves, and the performance of individual nodes even affects the performance of the collation system, and it is master-slave node processing data, there are data can tamper, system terminal is too single and so on. The contribution of this paper lies in the overall structure and technical route of the new rural cooperative medical system, and the optimization method of data flow of heterogeneous nodes, which can effectively save the scale and cost of the cluster, with the help of blockchain technology to ensure the security and credibility of data, optimize the front-end cluster service architecture, support multi-channel and high-concurrent key information push mode, has a very good promotion.
Innovation in the Learning Management System (LMS)
Authors: Brown Katie
Published: March 2021

This qualitative study identifies design principles and delivery methods best suited for the retail industry with a focus on training front-line workers. This research identifies key design elements to aid retail organizations in choosing an effective online learning solution for their workforce. To provide clear and relevant design recommendations specific to the retail workforce, the scope of the research focused on learner characteristics, e-learning in the workplace, adult learning theory, as well as current design and delivery features available on the market. Through a meta-synthesis of qualitative research, findings indicate a need for soft skill development related to customer interactions. A list of design principles targeting soft skill development of the front-line retail worker is recommended based on both industry and academic research.
Identifying Blind Spots in Leadership Development
Authors: Turner Timothy W. , Conroy Richard J.
Published: March 2021

A plethora of market available 360-degree assessment tools add value to the work of organizational leadership and management professionals. This chapter examines 360-degree assessments in terms of leadership development, training, and coaching. Multi-rater assessment use is reviewed in the context of emotional intelligence competencies. Leadership development is enhanced when benchmarks are established for leaders in the area of emotional intelligence. Organizations can identify keys to leader development by recognizing specific competencies in “star performers” (high performers). Self-report assessment instruments are generally useful in identifying key leadership competencies, but are limited by an individual's self-awareness. 360-degree multi-rater assessments enhance and support the recognition of these specific competencies but more so serve to identify blind spots or gaps in competency areas. Any divergence is often between a leader's self-reporting and observations gleaned from a 360-degree perspective by peers, subordinates, managers, family members, friends, and others.
Nature and Geography
Authors: Smith Brent
Published: March 2021

This chapter considers the appropriateness and importance of including the natural environment (i.e., nature and geography) as part of the external business environment featured in marketing textbooks. Based on myriad examples from industry, the natural environment is regarded as an uncontrollable force that constantly affects decisions about markets and marketing activities. Thus, it deserves some (greater) mention next to economic, competitive, regulatory, and other variables typically featured in most marketing textbooks. Based on a review of business news, industry concerns, and marketing textbooks, this chapter considers the current listing of uncontrollable environment forces typically discussed within twenty-five popular marketing textbooks. It is observed that nature and geography, common priorities for business decision makers, are conspicuously absent from mention within most of these textbooks. This chapter shows that the natural environment is mentioned in only five of twenty-five marketing textbooks: two introductory marketing; one marketing management; and two international marketing. Based on scholarly definitions and industry examples, nature and geography are, in fact, uncontrollable influential forces that affect markets and marketing activities. Consequently, there is reasonable cause for including them in more marketing textbooks. Textbook authors and instructors can provide students a more complete picture of how domestic and international markets and marketing activities are affected by the natural environment. In practice, business people acknowledge that the natural environment affects and is affected by markets and marketing activities in virtually all industries. Alas, marketing textbooks seldom little, if ever, acknowledge that nature and geography (e.g., topography, climate, weather, solar flares, natural disasters) affect how companies think about their markets and marketing mix. This chapter offers simple, actionable steps for discussing the natural environment in marketing textbooks and courses.
The Use of Discrete-Event Simulation for Business Education
Authors: Zekić-Sušac Marijana , Has Adela , Knežević Marinela
Published: March 2021

A new teaching approach is presented which integrates observational learning through field teaching of business processes and simulation modeling in order to increase students' learning outcomes and acceptance of computer simulation technology. The teaching method, called LOSI (learning by observing, simulating, and improving), was conducted at a Croatian high education institution. The efficiency of the LOSI approach was investigated by conducting a survey based on the technology acceptance model (TAM). The indicators of ease of use, usefulness, and enjoyment in participating in LOSI were collected along with students' grades and their intention to use this technology in future work and education. The inter-relations among variables were analyzed by statistical tests. The results revealed that students find LOSI easy to use, useful in achieving learning outcomes, and highly enjoyable, while the ease of use and enjoyment is positively associated to usefulness (i.e., learning outcomes).
Kindling Research Interest in Undergraduate Business Students
Authors: Starr-Glass David
Published: March 2021

Undergraduate Research Experiences (UREs) provide a means of encouraging, engaging, and supporting students in the co-production of relevant and legitimate knowledge. Research-centered experiences can be designed as capstones at the conclusion of the undergraduate degree, integrated into single courses or sequence of interrelated courses, or form an element of internships, community-based projects, service-learning experiences, and practicums. UREs have a high impact on student engagement and learning, and can serve as vehicles for establishing the student's distinctive personal signature on his or her learning. However, despite their value, UREs are underutilized in business education. This chapter explores some of the reasons for this, suggests ways through which undergraduates might be introduced to research, and argues that an involvement in relevant scholarly endeavor plays a significant part in the future success of business graduates.
Simulations in Business Education
Authors: Aguilera-Castillo Andres , Guerrero-Cabarcas Mauricio , Fúquene Camila Andrea , Rios William Fernando
Published: March 2021

This chapter examines the experimental use of Cesim™ Global Challenge, a computer-based business simulation, in an undergraduate international business program in Bogota, Colombia. The authors analyzed the data from the simulation through the application of a nonparametric statistical analysis, in addition to the application of an ex-post survey instrument, in order to assess the relevance of using simulations in the acquisition of managerial skills among undergraduate students. Key findings include the observation of positive effects of computer simulations in learning environments, as they occur in the literature. The authors accepted the hypothesis that stated that more time spent in the simulation leads to better results in the default winning criteria. Finally, the survey instrument confirmed that the use of the simulation helped the students develop managerial soft skills.
Paradigm Shift in Management Education
Authors: Nayak Smitha , Prabhu Nandan
Published: March 2021

Scholars, in the field of management education, have questioned the efficacy of current focus of business education in creating effective managers. Gulf between theory and practice, undue emphasis on conceptual knowledge, and lamentable attention to knowledge assimilation are cited as the prominent reasons for significantly low level of managerial effectiveness. In this regard, this chapter analyses the current paradigms of management education in its attempt to make a case for the need for a paradigm shift in education. Review of prior research clearly articulates the need for a cross functional approach to management education to bridge the gap between theory and its application. Further, this chapter discusses the dimensions of the process-orientation paradigm that it articulates. Potential contributions of process orientation paradigm and challenges before the cross-functional perspective of management education are also presented.
Education and Business
Authors: Klimova Tatiana
Published: March 2021

The chapter is devoted to the research of interaction between business structures and educational institutions. The current state of the problem is described through the analysis of the sociocultural situation, features of communication, and behavioral stereotypes. The reasons for impeding and facilitating their successful interaction are considered. The work is based on a series of interviews with representatives of the business community, education, and university students. The results obtained suggest possible forms of effective cooperation and formulate a number of recommendations.