Miracle-dz/UniFAR-FTUs huggingface dataset:
Transition from ventricular fibrillation to ventricular tachycardia: a simulation study on the role of Ca2+-channel blockers in human ventricular tissue

We study the effect of blocking the L-type Ca2+-channel on fibrillation in simulations in two-dimensional (2D) isotropic sheets of ventricular tissue and in a three-dimensional anisotropic anatomical model of human ventricles, using a previously developed model of human ventricular cells. Ventricular fibrillation (VF) was obtained as a result of spiral wave breakup and consisted of a varying number of chaotically wandering wavelets activating tissue at a frequency of about 6.0 Hz. We show that blocking the Ca2+-current by 75% can convert ventricular fibrillation into a periodic regime with a small number of stable spiral waves, ranging from six in 2D sheets of 25 × 25 cm to a single spiral in the anatomical model of human ventricles. The dominant frequency during this process changed to about 10.0 Hz in the 2D simulations, but to only 5.0 Hz in the whole heart simulations where a single spiral wave anchored around an anatomical obstacle. We show that the observed effects were due to a flattening of the electrical restitution curve, which prevented the generation of wave breaks and stabilized the activation patterns.
Reply to comment on `The stepped nature of lightning and the upward connecting streamer'

A response to the comments on `The stepped nature of lightning and the upward connecting stream' J. Phys. D: Appl. Phys. 35 L69–73. We thank Professor Sigmond for his stimulating comments [1]. However, we disagree with the statement that the results are seriously in error; rather, we consider that the results are the solution obtained using a simple model showing the general nature of streamer propagation over large distances. More complex models can be envisaged, but cannot be solved at this time.
Ultrasonics

An account at an elementary level is given of the physical aspects of ultrasonics. The more common types of generators and receivers are described, with special emphasis on those utilizing the piezoelectric and magnetorestrictive effects. Measurements and applications at low intensities (i.e. within elastic limits) are outlined and suggestions for some experiments suitable for school and undergraduate laboratories are made. The account concludes with a short section on the use of high-intensity ultrasonics.
Impacts of intellectual capital on process innovation and mass customisation capability: direct and mediating effects

This paper presents an empirical survey study. We propose a model to examine the individual and joint effects of the three components of intellectual capital (i.e. human, social and structural capital) on process innovation and mass customisation (MC) capability. The hypotheses are empirically tested using structural equation modelling and data collected from 645 manufacturing plants in 10 countries/regions. The results show that human and social capital are positively associated with structural capital. Human capital directly improves both process innovation and MC capability. The direct effect of social capital on MC capability and that of structural capital on process innovation is positive and significant. Moreover, process innovation is positively associated with MC capability. In addition, we find that structural capital mediates human and social capital’s effects on process innovation, and process innovation mediates human and structural capital’s effects on MC capability. This study contributes to the literature by providing insights into how human, social and structural capital jointly improve process innovation and MC capability, as well as how the different types of knowledge residing in a manufacturer affect MC capability development.
PENGARUH MEDIA WEB PADA PEMBELAJARAN INKUIRI TERBIMBING DIKOMBINASIKAN DENGAN LESSON STUDY TERHADAP BERPIKIR KREATIF DAN HASIL BELAJAR SISWA PADA MATERI LAJU REAKSI

Penelitian ini bertujuan untuk mengetahui : (1) Apakah hasil belajar siswa yang diajarkan pada pembelajaran inkuiri terbimbing dikombinasikan dengan lesson study menggunakan media web lebih tinggi daripada tanpa menggunakan media web ; (2) Apakah berpikir kreatif siswa yang diajarkan pada pembelajaran inkuiri terbimbing dikombinasikan dengan lesson study menggunakan media web lebih tinggi daripada tanpa menggunakan media web ; (3) Apakah ada hubungan kemampuan berpikir kreatif terhadap hasil belajar siswa. Penelitian ini bersifat eksperimen semu (quase experiment). Populasi penelitian adalah siswa kelas XI IPA SMA. Teknik pengambilan sampel adalah Simple random sampling yang terdiri dari dua kelas yaitu kelas eksperimen yang diajarkan pada pembelajaran inkuiri terbimbing dikombinasikan dengan lesson study menggunakan media web dan kelas kontrol yang diajarkan tanpa menggunakan media web dengan jumlah sampel seluruhnya 76 siswa. Instrument penelitian ini berupa tes berpikir kreatif dan hasil belajar siswa. Telah dilakakukan uji persyaratan berupa uji normalitas, homogenitas, yang diperoleh hasil bahwa data normal dan homogen. Teknik analisa data dilakukan dengan Independen Samples Tes (T-tes). Hasil penelitian menunjukkan bahwa: (1) Hasil belajar siswa yang diajarkan pada pembelajaran inkuiri terbimbing dikombinasikan dengan lesson study menggunakan media web dengan rata-rata gain sebesar 0,71 lebih tinggi daripada tanpa menggunakan media web dengan rata-rata gan sebesar 0,60 dengan signifikansi (0,00 < 0,05); (2) Berpikir kreatif siswa yang diajarkan pada pembelajaran inkuiri terbimbing dikombinasikan dengan lesson study menggunakan media web dengan rata-rata sebesar 75,46 lebih tinggi daripada tanpa menggunakan media web dengan rata-rata sebesar 55,20 dengan signifikansi (0,00 < 0,05); (3) Terdapat hubungan kemampuan berpikir kreatif terhadap hasil belajar siswa pada kelas eksperimen.
Quantum hadrodynamics

In future experiments, nuclear systems will be examined under extreme conditions of density and temperature, and their response will be probed at momentum and energy transfers larger than the nucleon mass. It is therefore essential to develop reliable nuclear models that go beyond the traditional nonrelativistic many-body framework, which is based on the Schrodinger equation. General properties of physics, such as quantum mechanics, Lorentz covariance and microscopic causality, motivate the use of quantum field theories to describe the interacting, relativistic, nuclear many-body system. The arguments for renormalizable models based on hadronic degrees of freedom (quantum hadrodynamics) are presented, and the assumptions underlying this framework are discussed. The Walecka model, which contains neutrons, protons, and neutral scalar and vector mesons, is considered first as a simple example. The development is based on the relativistic mean-field and Hartree approximations, and their application to infinite matter and atomic nuclei. Some successes of this model are discussed, such as the nuclear equation of state, the derivation of the shell model, the prediction of nuclear properties throughout the periodic table, and the inclusion of zero-point vacuum corrections. The important concepts of Lorentz covariance and self-consistency are emphasized, and the new dynamical features that arise in a relativistic many-body framework are highlighted. The computation of isoscalar magnetic moments is presented as an illustrative example. Calculations beyond the relativistic mean-field and Hartree approximations (for example, Dirac-Hartree-Fock and Dirac-Brueckner) are considered next, as well as recent efforts to incorporate the full role of the quantum vacuum in a consistent fashion. An extended model containing isovector pi and rho mesons is then developed; the dynamics is based on the chirally invariant linear sigma model. The difficulties in constructing realistic chiral descriptions of nuclear matter and nuclei are analysed, and the connection between the sigma model and the Walecka model is established. Finally, the relationship between quantum hadrodynamics and quantum chromodynamics is briefly addressed.
Black-brane instability in an arbitrary dimension

The black-hole–black-string system is known to exhibit critical dimensions and therefore it is interesting to vary the spacetime dimension D, treating it as a parameter of the system. We derive the large D asymptotics of the critical, i.e. marginally stable, string following an earlier numerical analysis. For a background with an arbitrary compactification manifold we give an expression for the critical mass of a corresponding black brane. This expression is completely explicit for Tn, the n-dimensional torus of an arbitrary shape. An indication is given that by employing a higher dimensional torus, rather than a single compact dimension, the total critical dimension above which the nature of the black-brane–black-hole phase transition changes from sudden to smooth could be as low as D ⩽ 11.
Adaptive surrogate models for reliability analysis and reliability-based design optimization

This thesis is a contribution to the resolution of the reliability-based design optimization problem. This probabilistic design approach is aimed at considering the uncertainty attached to the system of interest in order to provide optimal and safe solutions. The safety level is quantified in the form of a probability of failure. Then, the optimization problem consists in ensuring that this failure probability remains less than a threshold specified by the stakeholders. The resolution of this problem requires a high number of calls to the limit-state design function underlying the reliability analysis. Hence it becomes cumbersome when the limit-state function involves an expensive-to-evaluate numerical model (e.g. a finite element model). In this context, this manuscript proposes a surrogate-based strategy where the limit-state function is progressively replaced by a Kriging meta-model. A special interest has been given to quantifying, reducing and eventually eliminating the error introduced by the use of this meta-model instead of the original model. The proposed methodology is applied to the design of geometrically imperfect shells prone to buckling.
Parallel Adaptive High-Order CFD Simulations Characterizing Cavity Acoustics for the Complete SOFIA Aircraft

This paper presents one-of-a-kind MPI-parallel computational fluid dynamics simulations for the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is an airborne, 2.5-meter infrared telescope mounted in an open cavity in the aft of a Boeing 747SP. These simulations focus on how the unsteady flow field inside and over the cavity interferes with the optical path and mounting of the telescope. A temporally fourth-order Runge-Kutta, and spatially fifth-order WENO-5Z scheme was used to perform implicit large eddy simulations. An immersed boundary method provides automated gridding for complex geometries and natural coupling to a block-structured Cartesian adaptive mesh refinement framework. Strong scaling studies using NASA’s Pleiades supercomputer with up to 32,000 cores and 4 billion cells shows excellent scaling. Dynamic load balancing based on execution time on individual AMR blocks addresses irregularities caused by the highly complex geometry. Limits to scaling beyond 32K cores are identified, and targeted code optimizations are discussed.
THREE-DIMENSIONAL MAPS OF THE MAGELLANIC CLOUDS USING RR LYRAE STARS AND CEPHEIDS. I. THE LARGE MAGELLANIC CLOUD

The new data for Cepheids and RR Lyrae stars of the Optical Gravitational Lensing Experiment (OGLE III) survey allow us to study the three-dimensional distribution of stars corresponding to young (a few tens to a few hundreds of millions of years) and old (typically older than ∼9 Gyr) populations of the Large Magellanic Cloud (LMC) traced by these variable stars. We estimate the distance to 16,949 RR Lyrae stars by using their photometrically estimated metallicities. Furthermore, the periods of 1849 Cepheids are used to determine their distances. Three-dimensional maps are obtained by using individual reddening estimates derived from the intrinsic color of these stars. The resulting median distances of the RR Lyrae stars and Cepheids appear to resolve the long and short distance scale problem for our sample. With median distances of 53.1 ± 3.2 kpc for the RR Lyrae stars and 53.9 ± 1.8 kpc for the Cepheids, these two distance indicators are in very good agreement with each other in contrast to a number of earlier studies. Individual reddening estimates allow us to resolve the distance discrepancies often observed while comparing Cepheids and RR Lyrae stars. For both stellar populations we find the inclination angle of the LMC to be 32° ± 4° and the mean position angle to be 115° ± 15°. The position angle increases with galactocentric radius, indicative of mild twisting. Within the innermost 7° of the LMC covered by OGLE III, the change in position angle amounts to more than 10°. The depth of the Cepheids is found to be 1.7 ± 0.2 kpc. The bar stands out as an overdensity both in RR Lyrae stars and in Cepheids. In RR Lyrae stars the bar can be traced as a protruding overdensity with a line-of-sight depth of almost 5 kpc in front of the main body of the disk.
Teaching lean manufacturing at a postgraduate level

Purpose This study aims at integrating two teaching approaches to enhance Lean manufacturing (LM) learning at a graduate course level and verify its effectiveness through comparing students’ performance and learning preferences. Design/methodology/approach The proposed methodology incorporates problem-based learning (PBL) approach based on real problems of companies undergoing a lean implementation into traditional teaching methods. The methodology was applied with graduate students from a Brazilian public university, whose learning preferences were subsequently identified. The verification of effectiveness is undertaken through a comparative analysis of students’ performance after each course. Findings The findings indicate that PBL may be an effective complementary method for LM learning, especially because it exposes students to actual problems when implementing LM. The proposal may improve problem-solving ability and provide a more fertile environment to promote better learning experience. The results are also positively related to the current body of the literature. Finally, because of different students’ learning preferences, PBL alone may not fulfill all students’ cognitive requirements, and hence, traditional teaching methods should not be eradicated from the LM learning process. Originality/value Because of an increasingly worldwide competition regarding business performance, LM has been an emerging and relevant subject among engineering and management postgraduate courses. Nevertheless, the practical character inherent to the understanding of LM may undermine learning and development of students. Therefore, studies that verify the effectiveness of the teaching approach may contribute to better prepare students for such demanding context.
Topological Singularities in Wave Fields

This thesis is a study of the natural geometric structures, arising through interference, in fields of complex waves (scalars, vectors or tensors), where certain parameters describing the wave are singular. In scalar waves, these are phase singularities (also called wave dislocations), which are also nodes (zeros of amplitude): in two dimensional fields they are points, and in three dimensions, lines. The morphology of dislocation points and lines is studied in detail, and averages of their geometrical properties (such as density, speed, curvature and twistedness) are calculated analytically for isotropically random gaussian ensembles (superpositions of plane waves equidistributed in direction, but with random phases). It is also shown how dislocation lines may be knotted and linked, and a construction of torus knots in monochromatic waves is studied in detail, using experimentally realisable beams. In vector waves, the appropriate fields are described geometrically by an ellipse at each point (the polarization ellipse). Their singularities, occurring along lines in three dimensions, are where the ellipse is circular (C lines) and linear (L lines); in two dimensional fields, possibly representing the transverse plane of paraxial polarized light waves, there are C points, but still L lines. The geometry of these singularities is considered, and analytical calculations for their densities in isotropic gaussian random vector waves are performed. The C and L singularity structures are generalised to fields of spinors using the Majorana sphere (vector fields have spin 1), and singularities in rank two tensor waves (spin 2) are briefly discussed.
The effect of graphene on the yarn pull-out force and ballistic performance of Kevlar fabrics impregnated with shear thickening fluids

The ballistic performance of Kevlar fabric impregnated with different shear thickening fluids (STFs) were investigated at various impact velocities. The SiO2 nanoparticle based STFs were reinforced with graphene and showed a significant increase in viscosity and shear thickening efficiency compared to pure STF. Ballistic experiments were performed on fabric treated by different STFs, and different failure modes including yarn slipping, extraction, and breakage in shear failure were obtained. To better understand how different STFs affect ballistic performance, single yarn pull-out tests were also carried out to examine the shear strength and friction between the interlocking yarns of fabric treated with STF. The results showed that STF reinforced with graphene is better at preventing the yarns from slipping, and the single yarn pull-out force is almost 5 times more than pure STF. Moreover, reinforced STF also has a significant influence on the ballistic limit and energy absorption of Kevlar fabrics. And the increased amplitude of energy absorption is almost 20% more than the pure STF/Kevlar load case. Combining with the energy absorption and different failure modes, the effect of STF on the failure mechanism of neat/treated fabric was also discussed.
Objective Voice Parameters in Colombian School Workers with Healthy Voices

Objetivos: Caracterizar los parametros objetivos de la voz en trabajadores escolares e identificar los factores asociados de tres parametros objetivos de la voz (frecuencia fundamental, presion sonora y tiempo maximo de fonacion). Materiales y metodos: Estudio transversal en el que participaron 116 profesores y 20 no profesores colombianos. Despues de firmar el consentimiento informado, los participantes diligenciaron un cuestionario. Posteriormente, grabaron una muestra de voz, la cual fue analizada, perceptualmente, por una fonoaudiologa y, objetivamente, con el software praat. Se realizaron mediciones ambientales de niveles de ruido, temperatura, humedad y tiempos de reverberacion durante las visitas a los lugares de trabajo, tales como salones y oficinas. Analisis de los factores individuales y ocupacionales asociados con los parametros de la voz fueron reali­zados por medio de regresiones lineales. Resultados: Comparadas con sus pares masculinos, las trabajadoras escolares registraron frecuencia fundamental mas aguda (201 Hz para las profesoras y 209 para las no-profesoras frente a 120 Hz para los profesores y 127 para los no-profesores) e intensidad mas alta (82 dB frente 80 dB), y tiempo maximo de fonacion mas corto (14 segundos aproximadamente frente a 16 segundos aproximadamente). Las profesoras menores de 50 anos evidenciaron una tendencia significativa a producir una frecuencia fundamental mas baja y un tmf mas corto, comparadas con las profesoras mayores de 50 anos. Las profesoras registraron frecuencia fundamental significativamente mas alta (66 Hz), intensidad mas alta (2 dB) y tiem­po maximo de fonacion mas corto (2 segundos) comparadas con los profesores. Conclusion: Las profesoras menores de 50 anos registraron frecuencia fundamental mas baja y tmf mas corto compradas con las profesoras mayores de 50 anos. El analisis multivariado mostro que genero fue una variable mucho mas importante para determinar la variacion en F0, spl y tmf que edad u ocupacion. La temperatura dentro de los lugares de trabajo (medida objetivamente) tambien contribuye a los cambios en intensidad de la voz entre los trabajadores escolares.
On the topology of spaces of functions without complex singularities

An important characteristic of a manifold is the topological structure of the space of maps from it to R" with no critical points of a certain type. For an investigation into such spaces see, for example, [1] -[4]; see [1], [2], [5] for applications. In this note we describe a method of calculating the cohomologies of such spaces. One of the corollaries of this method is a theorem of Hirsch-Smale type (Theorem 2) which reduces these spaces to spaces of admissible sections of jet bundles. I am grateful to V.I. Arnol'd for posing this problem.
Device Aging in Analog Circuits for Nanoelectronic CMOS Technologies

The trend in microelectronics to reduce device dimensions leads to increasing and new aging effects in the devices. This requires a continuous optimisation of the fabrication process as well as a degradation aware circuit design, to guarantee a high reliability of the functional elements and maintain the stable function of the system. This work focuses on the very sensitive analog circuits. Previous investigations had presented heterogeneous results. Therefore, a throughout and universal study, investigating the impact of several different aging effects on the analog circuitry, had to be performed. This work identifies highly aging sensitive circuit blocks and demonstrates the impact of device wear-out on their performance characteristics with particularly developed models and experiments. Furthermore, universal methodologies for accelerated stress measurements, aging suppression and design guidelines are proposed and evaluated.
PHYSICOCHEMICAL CHARACTERISTICS OF MALAYSIAN HONEYS INFLUENCED BY STORAGE TIME AND TEMPERATURE

Honey is a natural product that produced by honeybees or stingless bees. Consumers always found the best quality of honey by observing the physicochemical properties. However, storage time and temperature can affect the quality of honey. This study aimed to determine the physicochemical properties (moisture content, pH, water activity and turbidity) of Hutan, Kelulut, Gelam, Acacia honeys stored at different temperatures (-20, 4 and 25 o C) up to 300 days and to identify the storage conditions suitable to be applied for each type of honey. The results of this study showed that the quality of Malaysian honeys were affected by the storage times and temperatures. Hutan honey was found to be very sensitive to low temperature condition. Thus, it is recommended that Hutan honey should be stored at room temperature to retain its quality. Keywords: physicochemical characteristics; storage; Malaysian honeys
Recording of short-term finger blood pressure changes induced by an arterial occlusive thigh cuff: comparison between the modified oscillometric and Finapres techniques

Blood pressure recordings obtained by the volume clamp method (Finapres monitor, Ohmeda, USA) were compared with measurements by using a novel modification of the oscillometric method (UT9201 beat-to-beat monitor, University of Tartu, Estonia). Step changes in total peripheral resistance were introduced in 11 healthy volunteers by rapid inflation to the suprasystolic pressure of bilateral thigh cuffs during a rhythmical exercise with the quadriceps muscles and simultaneously performed handgrip compression. The provoked short-term changes in mean arterial pressure (MAP) were similarly tracked by both devices. The agreement between the methods was better for MAP rise than drop. The group-averaged difference UT9201 minus Finapres did not exceed 1.2 mmHg (NS, p = 0.46) after cuff successive inflation but yielded 3.8 mmHg (significant, p < 0.05) after cuff successive deflation.