bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectral asymptotics of the Laplacian on Platonic solids graphs
Authors: Exner Pavel , Lipovský Jiří
Published: December 2019

We investigate the high-energy eigenvalue asymptotics of quantum graphs consisting of the vertices and edges of the five Platonic solids considering two different types of the vertex coupling. One is the standard δ-condition and the other is the preferred-orientation one introduced in the work by Exner and Tater [Phys. Lett. A 382, 283–287 (2018)]. The aim is to provide another illustration of the fact that the asymptotic properties of the latter coupling are determined by the vertex parity by showing that the octahedron graph differs in this respect from the other four for which the edges at high energies effectively disconnect and the spectrum approaches the one of the Dirichlet Laplacian on an interval.
Atomically-resolved interface imaging and terahertz emission measurements of gallium arsenide epilayers
Authors: Balgos M. H. , Jaculbia R. , Prieto E. A. , Tani M. , Estacio E. , Salvador A. , Somintac A. , Hayazawa N. , Kim Y.
Published: December 2019

Semiconductor interfaces are the backbone of modern optoelectronic devices. In terahertz (THz) science, the narrow region of an interface is crucial in the emission process. However, reports on the direct correlation of THz emission with local interface properties remain scarce owing to the inherent difficulty of using the same sample for nanoscale and macroscale studies. In this study, we combined scanning tunneling microscopy/spectroscopy (STM/STS) and THz emission spectroscopy to study the interface between a highly n+-doped and undoped gallium arsenide (GaAs). Using STS, we identify a carrier density of 1×1015 cm−3 in the low-temperature-grown GaAs (LT-GaAs) layer, which we used to visualize the energy band diagram at the interface and the surface of LT-GaAs. THz emission intensity is higher in the LT-GaAs/n+-GaAs structures relative to semi-insulating GaAs owing to the high electric field at the interface regardless of the LT-GaAs layer thickness. Pump fluence dependence of THz showed that the thinner LT-GaAs layers saturate at lower pump fluence compared to thicker LT-GaAs and SI-GaAs. This behavior is explained by the built-in field screening by the photogenerated carriers and the free carriers from the n+-GaAs to the LT-GaAs. Our results demonstrate the utility of STM/STS to the design of semiconductor-based THz emitters.
Structural, electronic, transport and magnetic studies of LaCo1 − xNixO3 (x = 0, 0.3) thin films
Authors: Kumar Ashok , Kumar Vinod , Shukla Dinesh , Kumar Rajesh , Choudhary Ram Janay , Kumar Ravi
Published: December 2019

We present here a study on structural, electronic, transport, and magnetic properties of single-phase (001) oriented compressively strained thin films of LaCoO3 (LCO) and LaCo0.7Ni0.3O3 (LCNO). The films were deposited on the LaAlO3 (001) single crystal substrate using pulsed laser deposition. Electronic structure investigations by x-ray absorption spectroscopy (XAS) measurements at various edges (Co-L3,2, Ni-L3,2, and La-M5,4) confirm +3 charge states for Co, Ni, and La ions in all samples. The XAS study also reveals a transition in the spin state of Co+3 (low spin to intermediate/high spin), which is attributed to induced strain and Ni substitution. Electrical transport measurements suggest the semiconducting behavior for LCO and LCNO thin films in the measured temperature range. We found a drastic change in resistivity (ρ) and magnitude with Ni substitution. An in-depth analysis of the conduction mechanism governing the transport behavior in thin films has been done using various theoretical models. Different conduction mechanisms (Arrhenius law and Effros-Shklovski-type variable range hopping) have been observed to govern conduction in different temperature ranges, suggesting disorder controlled transport in these films. The magnetization measurements show a magnificent increase in saturation magnetization for LCNO and ferromagnetic ordered states, which persists even up to room temperature.
Triple points and sign of circulation
Authors: Elling Volker
Published: December 2019

Interaction of multiple shock waves generally produces a contact discontinuity whose circulation has previously been analyzed using “thermodynamic” arguments based on the Hugoniot relations across the shocks. We focus on “kinematic” techniques that avoid assumptions about the equation of state, using only jump relations for the conservation of mass and momentum but not energy. We give a new short proof for the nonexistence of pure (no contact) triple shocks, recovering a result of Serre. For Mach reflection with a zero-circulation but nonzero-density-jump contact, we show that the incident shock must be normal. Nonexistence without contacts generalizes to two or more incident shocks if we assume that all shocks are compressive. The sign of circulation across the contact has previously been controlled with entropy arguments, showing that the post-Mach-stem velocity is generally smaller. We give a kinematic proof assuming compressive shocks and another condition, such as backward incident shocks, or a weak form of the Lax condition. We also show that for 2 + 2 and higher interactions (multiple “upper” shocks with clockwise flow meeting multiple “lower” shocks with counterclockwise flow in a single point), the circulation sign can generally not be controlled. For γ-law pressure, we show that 2 + 2 interactions without contacts must be either symmetric or antisymmetric, with symmetry favored at low Mach numbers and low shock strengths. For full potential flow instead of the Euler equations, we surprisingly find, contrary to folklore and prior results for other models, that pure triple shocks without contacts are possible, even for γ-law pressure with 1 < γ < 3.
A combination of plasma diagnostics and Raman spectroscopy to examine plasma-graphene interactions in low-pressure argon radiofrequency plasmas
Authors: Vinchon P. , Glad X. , Robert-Bigras G. , Martel R. , Sarkissian A. , Stafford L.
Published: December 2019

Graphene films were exposed to low-pressure capacitively coupled (E-mode) and inductively coupled (H-mode) argon radio frequency plasmas to investigate damage formation by very-low-energy ion irradiation. In the H-mode, plasma parameters were assessed by a Langmuir probe and plasma sampling mass spectrometry to determine the conditions of fixed ion fluence but with different average ion energies. The populations of argon metastable and resonant argon atoms were also measured by optical absorption spectroscopy to determine their contribution to the total energy flux during plasma treatment. In the H-mode, in which plasma-graphene interactions are dominated by ion irradiation effects, Raman spectroscopy reveals a significant rise in the D/G ratio and full width at half maximum of the G peak as well as the onset of graphene amorphization, even at very low ion energies (between 7 and 13 eV). In the E-mode characterized by comparable ion energy but much lower ion density, significant damage is also observed, a feature ascribed to the additional energy flux linked to the de-excitation of metastable argon species on the graphene surface.
Advanced material system for the design of an intermediate band solar cell: Type-II CdTe quantum dots in a ZnCdSe matrix
Authors: Deligiannakis V. , Ranepura G. , Kuskovsky I. L. , Tamargo M. C.
Published: December 2019

We explore CdTe fractional monolayer quantum dots (QDs) in a ZnCdSe host matrix for potential application in an intermediate band solar cell device. Careful consideration has been taken during the initiation of the growth process of QDs by migration enhanced epitaxy, in order to avoid the formation of undesirable interfacial layers that can form due to the lack of common anion between the two materials. A superlattice structure of 100 periods of alternating QD and spacer layers is analyzed by high-resolution X-ray diffraction (XRD) and photoluminescent (PL) spectroscopy. Simple arguments are used following continuum elastic theory to deduce the size of the dots and the strain within the superlattice from XRD data. This is further verified using PL and used in the energy calculations that yield the values of the intermediate band energy. The results suggest that the optimized materials are highly suitable for these high efficiency solar cells.
A quick algorithm for evaluation of minimum zone circles from polar coordinate data
Authors: Li Xiuming , Liu Yuwei
Published: December 2019

It is very important to select the initial four candidate points of the minimum zone circles to improve the computational efficiency. According to the radius of the measured points, three models of error evaluation are proposed and corresponding algorithms are given for evaluating the minimum zone circles based on the lower envelope lines, four-point intersection principle, and bisection method. The points constructing the lower envelope lines can be used for the evaluation of the maximum inscribed circle. Several examples have been carried out to validate the validity of the proposed algorithm.
Charge transport mechanism in SiNx-based memristor
Authors: Gismatulin A. A. , Gritsenko V. A. , Yen T.-J. , Chin A.
Published: December 2019

Amorphous silicon nitride is a key dielectric in silicon devices. The advantage of SiNx and Si3N4 over other dielectrics is that silicon nitride is compatible with silicon technology and is widely used in it. It is necessary to understand, experimentally and theoretically, the mechanism of charge transport in a memristor based on silicon nitride in the initial, high-resistance, and low-resistance states to develop a resistive memory element. At present, there is currently no single universal model of charge transport in a memristor based on silicon nitride. In our work, the charge transport of the initial, high, and low resistive states in an SiNx-based memristor is analyzed with four bulk-limited charge transport models. It is established that the Frenkel model of Coulomb traps ionization, Hill-Adachi model of overlapping Coulomb traps, and Makram-Ebeid and Lannoo model of multiphonon isolated traps ionization, quantitatively, do not describe the charge transport of the SiNx-based memristor in any state. The Nasyrov-Gritsenko model of phonon-assisted tunneling between traps gives a consistent explanation of the charge transport of the SiNx-based memristor in all states at temperatures above room temperature.
Perpendicular orbital and quadrupole anisotropies at Fe/MgO interfaces detected by x-ray magnetic circular and linear dichroisms
Authors: Okabayashi Jun , Iida Yuki , Xiang Qingyi , Sukegawa Hiroaki , Mitani Seiji
Published: December 2019

We investigated interfacial perpendicular magnetic anisotropy (PMA) in ultrathin Fe/MgO(001) using both x-ray magnetic circular dichroism and magnetic linear dichroism (XMLD). We developed the XMLD technique for detecting the signals from the PMA samples. The PMA energy and quadrupole moments at an Fe/MgO interface were deduced from the XMLD sum rules, whose values explain the microscopic origin of PMA. We found that orbital moment anisotropy is dominant at the Fe/MgO interfacial PMA and the contribution of quadrupole moments is small but finite at the lattice distorted interfaces.
Delay differential equation-based models of cardiac tissue: Efficient implementation and effects on spiral-wave dynamics
Authors: Moreira Gomes Johnny , Lobosco Marcelo , Weber dos Santos Rodrigo , Cherry Elizabeth M.
Published: December 2019

Delay differential equations (DDEs) recently have been used in models of cardiac electrophysiology, particularly in studies focusing on electrical alternans, instabilities, and chaos. A number of processes within cardiac cells involve delays, and DDEs can potentially represent mechanisms that result in complex dynamics both at the cellular level and at the tissue level, including cardiac arrhythmias. However, DDE-based formulations introduce new computational challenges due to the need for storing and retrieving past values of variables at each spatial location. Cardiac tissue simulations that use DDEs may require over 28 GB of memory if the history of variables is not managed carefully. This paper addresses both computational and dynamical issues. First, we present new methods for the numerical solution of DDEs in tissue to mitigate the memory requirements associated with the history of variables. The new methods exploit the different time scales of an action potential to dynamically optimize history size. We find that the proposed methods decrease memory usage by up to 95% in cardiac tissue simulations compared to straightforward history-management algorithms. Second, we use the optimized methods to analyze for the first time the dynamics of wave propagation in two-dimensional cardiac tissue for models that include DDEs. In particular, we study the effects of DDEs on spiral-wave dynamics, including wave breakup and chaos, using a canine myocyte model. We find that by introducing delays to the gating variables governing the calcium current, DDEs can induce spiral-wave breakup in 2D cardiac tissue domains.
Numerical investigation on evolutionary characteristics of the leading-edge vortex induced by flapping caudal fin
Authors: Xiong Zhongying , Liu Xiaomin
Published: December 2019

The caudal fin of a fish is one of the main determinants of various maneuvering motions. In this paper, the evolutionary characteristics of the leading-edge vortex (LEV) induced by three kinds of forked caudal fins with different chord lengths are studied. Numerical results show that the emergence and development of the LEV are directly related to the distribution law of the angle of attack (AoA) caused by the leading-edge configuration. However, when adopting a fixed motion mode, any temporal evolution in the AoA of the leading-edge location is determined by the distance between the leading-edge location and the pitching axis, the combined effects of heaving and pitching motions, and the Strouhal number. An increase in the chord length enhances the strength of the LEV, leading to more vortex-augmented thrust. Nonetheless, the chord length of a forked caudal fin cannot be extended indefinitely as this will alter the temporal evolution of the AoA and seriously delay the generation of the LEV. Our research is helpful in understanding how the locomotor force is derived from the motion of the caudal fin and provides a reference for biomimetic roboticists to choose appropriate propellers for underwater vehicles.
Aspect ratio studies on insect wings
Authors: Bhat S. S. , Zhao J. , Sheridan J. , Hourigan K. , Thompson M. C.
Published: December 2019

The wing aspect ratio (AR), that is, the ratio of the wingspan to the mean wing chord, is the most important geometrical parameter describing an insect wing. While studies have shown that a change in AR affects the flow structure as well as the aerodynamic force components on wings, the reasons behind the wide variety of aspect ratios observed in nature remain underexplored. Further to this, motivated by the developments in micro-air vehicles (MAVs), determining an optimum AR is important for their efficient operation. While the effects on flow structure appear to be, at least superficially, broadly consistent across different studies, the effects on aerodynamic forces have been more strongly debated. Indeed, the considerable variation of force coefficients with AR in different studies suggests different optimal ARs. To help explain this, recent studies have pointed out the coupled effects of AR with other parameters. Specifically, the use of Reynolds and Rossby numbers based on alternative scalings helps to at least partially decouple the effects of AR and also to reconcile previous conflicting trends. This brief review presents an overview of previous studies on aspect-ratio effects of insectlike wings summarizing the main findings. The suggested alternative scalings of Reynolds and Rossby numbers, using the wingspan as the characteristic length, may be useful in aiding the selection of the optimal aspect ratios for MAVs in the future.
Electronic and vibrational structure in the S and S1 states of corannulene
Authors: Kanaoka Ayumi , Tohyama Hiromi , Kunishige Sachi , Katori Toshiharu , Nishiyama Akiko , Misono Masatoshi , Nakayama Naofumi , Sakurai Hidehiro , Tsuge Masashi , Baba Masaaki
Published: December 2019

Corannulene is a nonplanar aromatic hydrocarbon also known as a buckybowl. Its electronic and vibrational structure has been investigated by analyzing its fluorescence excitation spectrum and dispersed fluorescence spectrum in a supersonic jet. Its spectral features are in keeping with the expectation, confirmed by some previous results, that it has fivefold or C5v symmetry. The observed prominent vibronic bands in the S1 ← S0 transition have been assigned to e1 and e2 bands on the basis of theoretical calculations so that the S1 state was assigned to 1E2. The symmetry adapted cluster configuration interaction calculation supports this assignment of the S1 electronic state, although the time-dependent density functional theory calculation suggests that the S1 state is 1A2. It has also been shown that the normal coordinates for strong vibronic bands mainly include out-of-plane vibrational motion. The rotational envelopes are well explained by taking account of the Coriolis interaction between the degenerate vibrational and rotational levels. The mechanism of bowl-to-bowl inversion is also discussed with the results of theoretical calculations regarding the barrier to inversion and metastable conformation.
Studying wave propagation to predict tsunamis
Authors: Mandel Savannah
Published: December 2019

A mathematical study analyzes the effects of walls on the stability of a fluid interface in shallow water flow.
Functions of perturbed pairs of noncommuting contractions
Authors: Aleksandrov A. B. , Peller V. V.
Published: December 2019

We consider functionsof pairs of noncommuting contractions on Hilbert space and study the problem as to which functionswe have Lipschitz type estimates in Schatten–von Neumann norms. We prove that ifbelongs to the Besov classof analytic functions in the bidisc, then we have a Lipschitz type estimate for functionsof pairs of not necessarily commuting contractionsin the Schatten–von Neumann normsfor. On the other hand, we show that for functions in, there are no such Lipschitz type estimates for, nor in the operator norm.
Uniqueness theorems for one-dimensional and double Franklin series
Authors: Gevorkyan G. G.
Published: December 2019

The paper contains two main results. First we describe one-dimensional Franklin series converging everywhere except possibly on a finite set to an everywhere-finite integrable function. Second we establish a class of subsets of

with the following property. If a double Franklin series converges everywhere except on this set to an everywhere-finite integrable function, then it is the Fourier–Franklin series of this function. In particular, all countable sets are in this class.
Existence and uniqueness of solution of a certain boundary-value problem for a convolution integral equation with monotone non-linearity
Authors: Khachatryan Kh. A.
Published: December 2019

We study the existence and uniqueness as well as the asymptotic behaviour of solutions of a certain boundary-value problem for a convolution integral equation on the whole line with monotone non-linearity. In some special cases, there are concrete applications to

-adic string theory, the mathematical theory of the geographical spread of an epidemic, the kinetic theory of gases and the theory of radiation transfer. We prove the existence and uniqueness of an odd bounded continuous solution. The monotonicity and the integral asymptotics of this solution is also discussed. We finally give particular application-oriented examples of the equations considered, which illustrate the special nature of our results.
Integer expansion in systems of translates and dilates of a single function
Authors: Filippov V. I.
Published: December 2019

We study expansions with integer coefficients of elements in the multidimensional spaces

,

, in systems of translates and dilates of a single function. We describe models useful in applications, including those in multimodular spaces. The proposed approximation of elements in

,

, has the property of image compression, that is, there are many zero coefficients in this expansion. The study may also be of interest to specialists in the transmission and processing of digital information since we find a simple algorithm for approximating in

,

, having this property.
Diffeomorphisms of 2-manifolds with one-dimensional spaciously situated basic sets
Authors: Grines V. Z. , Kurenkov E. D.
Published: December 2019

We consider orientation-preserving

-diffeomorphisms of orientable surfaces of genus greater than one with a one-dimensional spaciously situated perfect attractor. We show that the topological classification of restrictions of diffeomorphisms to such basic sets can be reduced to that of pseudo-Anosov homeomorphisms with a distinguished set of saddles. In particular, we prove a result announced by Zhirov and Plykin, which gives a topological classification of the

-diffeomorphisms of the surfaces under discussion under the additional assumption that the non-wandering set consists of a one-dimensional spaciously situated attractor and zero-dimensional sources.
Subdivision schemes on the dyadic half-line
Authors: Karapetyants M. A.
Published: December 2019

We consider subdivision schemes, which are used for the approximation of functions and generation of curves on the dyadic half-line. In the classical case of functions on the real line, the theory of subdivision schemes is widely known because of its applications in constructive approximation theory and signal processing as well as for generating fractal curves and surfaces. We define and study subdivision schemes on the dyadic half-line (the positive half-line endowed with the standard Lebesgue measure and the digit-wise binary addition operation), where the role of exponentials is played by Walsh functions.

We obtain necessary and sufficient conditions for the convergence of subdivision schemes in terms of the spectral properties of matrices and in terms of the smoothness of solutions of the corresponding refinement equation. We also investigate the problem of convergence of subdivision schemes with non-negative coefficients. We obtain an explicit criterion for the convergence of algorithms with four coefficients. As an auxiliary result, we define fractal curves on the dyadic half-line and prove a formula for their smoothness. The paper contains various illustrative examples and numerical results.
An in vivo RNAi screen uncovers the role of AdoR signaling and adenosine deaminase in controlling intestinal stem cell activity
Authors: Xu Chiwei , Franklin Brian , Tang Hong-Wen , Regimbald-Dumas Yannik , Hu Yanhui , Ramos Justine , Bosch Justin A. , Villalta Christians , He Xi , Perrimon Norbert
Published: December 2019

Significance

Regulation of stem cells by microenvironment signals is important to maintain epithelial homeostasis. Using a quantitative readout, we screened for receptor genes that affect the intestinal stem cell pool size in the adult
Drosophila
midgut. The top candidate of our screen,
AdoR
, underscores the importance of purinergic signaling in controlling ISC activity. Furthermore, we identified a pivotal role of an enterocyte-derived metabolic enzyme, Adgf-A, in limiting the activity of extracellular adenosine and shaping the ISC microenvironment.
Light-driven carbon−carbon bond formation via CO2reduction catalyzed by complexes of CdS nanorods and a 2-oxoacid oxidoreductase
Authors: Hamby Hayden , Li Bin , Shinopoulos Katherine E. , Keller Helena R. , Elliott Sean J. , Dukovic Gordana
Published: December 2019

Significance

Nature uses enzymes to catalyze a vast array of complex chemical reactions. Enzymes that catalyze reduction reactions require partners that provide the electrons ultimately used in catalysis. In nature, the associated electron transfer sequences can be complicated, energy-inefficient, and rate determining. Here, we employ artificial electron donors, photoexcited semiconductor nanocrystals, to provide the electrons for catalysis. We couple these nanocrystals with an enzyme that catalyzes the formation of carbon−carbon bonds via CO2reduction. With this architecture, we demonstrate light-driven formation of 2-oxoglutarate, storing some of the photon energy in the chemical product. We examine the role of electron transfer from the nanocrystal to the enzyme in the light-driven chemical conversion and learn that the enzyme modulates this process during catalysis.
Spectroscopic fingerprint of chiral Majorana modes at the edge of a quantum anomalous Hall insulator/superconductor heterostructure
Authors: Shen Junying , Lyu Jian , Gao Jason Z. , Xie Ying-Ming , Chen Chui-Zhen , Cho Chang-woo , Atanov Omargeldi , Chen Zhijie , Liu Kai , Hu Yajian J. , Yip King Yau , Goh Swee K. , He Qing Lin , Pan Lei , Wang Kang L. , Law Kam Tuen , Lortz Rolf
Published: December 2019

With the recent discovery of the quantum anomalous Hall insulator (QAHI), which exhibits the conductive quantum Hall edge states without external magnetic field, it becomes possible to create a topological superconductor (SC) by introducing superconductivity into these edge states. In this case, 2 distinct topological superconducting phases with 1 or 2 chiral Majorana edge modes were theoretically predicted, characterized by Chern numbers (

N

) of 1 and 2, respectively. We present spectroscopic evidence from Andreev reflection experiments for the presence of chiral Majorana modes in an Nb/(Cr
0.12
Bi
0.26
Sb
0.62
)
2
Te
3
heterostructure with distinct signatures attributed to 2 different topological superconducting phases. The results are in qualitatively good agreement with the theoretical predictions.
Universal relation with regime transition for sediment transport in fine-grained rivers
Authors: Ma Hongbo , Nittrouer Jeffrey A. , Wu Baosheng , Lamb Michael P. , Zhang Yuanfeng , Mohrig David , Fu Xudong , Naito Kensuke , Wang Yuanjian , Moodie Andrew J. , Wang Guangqian , Hu Chunhong , Parker Gary
Published: December 2019

Significance

Fine-grained sediment transport systems (grain size under 2,000 μm) are ubiquitous over time and space on Earth and extraplanetary surfaces, and include rivers, deltaic coastal settings, and submarine, lahar, and subglacial systems. Forecasting the evolution of Earth’s surface requires a predictive algorithm for sediment transport. Herein we provide a universal relation for sediment transport in fine-grained rivers. Surprisingly, it is shown that sediment flux differs by up to 2 orders of magnitude as grain size changes only slightly near the boundary between very fine sand and fine sand. The universal applicability of the sediment transport formulation enables quantitative understanding of the sedimentology and morphology of fine-grained rivers.
Molecular mechanism of leukocidin GH–integrin CD11b/CD18 recognition and species specificity
Authors: Trstenjak Nikolina , Milić Dalibor , Graewert Melissa A. , Rouha Harald , Svergun Dmitri , Djinović-Carugo Kristina , Nagy Eszter , Badarau Adriana
Published: December 2019

Host–pathogen interactions are central to understanding microbial pathogenesis. The staphylococcal pore-forming cytotoxins hijack important immune molecules but little is known about the underlying molecular mechanisms of cytotoxin–receptor interaction and host specificity. Here we report the structures of a staphylococcal pore-forming cytotoxin, leukocidin GH (LukGH), in complex with its receptor (the α-I domain of complement receptor 3, CD11b-I), both for the human and murine homologs. We observe 2 binding interfaces, on the LukG and the LukH protomers, and show that human CD11b-I induces LukGH oligomerization in solution. LukGH binds murine CD11b-I weakly and is inactive toward murine neutrophils. Using a LukGH variant engineered to bind mouse CD11b-I, we demonstrate that cytolytic activity does not only require binding but also receptor-dependent oligomerization. Our studies provide an unprecedented insight into bicomponent leukocidin–host receptor interaction, enabling the development of antitoxin approaches and improved animal models to explore these approaches.
Practices and attitudes toward replication in empirical translation and interpreting studies
Authors: Olalla-Soler Christian
Published: December 2019

This article presents the results of three studies on practices in and attitudes toward replication in empirical
translation and interpreting studies. The first study reports on a survey in which 52 researchers in translation and interpreting
with experience in empirical research answered questions about their practices in and attitudes toward replication. The survey
data were complemented by a bibliometric study of publications indexed in the Bibliography of Interpreting and Translation (BITRA)
(Franco Aixelá 2001–2019) that explicitly stated in the title or abstract that they
were derived from a replication. In a second bibliometric study, a conceptual replication of Yeung’s (2017) study on the acceptance of replications in neuroscience journals was conducted by analyzing 131
translation and interpreting journals. The article aims to provide evidence-based arguments for initiating a debate about the need
for replication in empirical translation and interpreting studies and its implications for the development of the discipline.
Membrane fusion and infection abilities of baculovirus virions are preserved during freezing and thawing in the presence of trehalose
Authors: Nakanishi Kohei , Tomita Masahiro , Tsumoto Kanta
Published: December 2019

Budded viruses (BVs) of baculovirus such as Autographa californica nucleopolyhedrovirus (AcNPV) have recently been studied as biological nanomaterials, and methods for their longer-term storage without deterioration would be desirable. The cryopreservation of virions with a naturally occurring saccharide like trehalose as a cryoprotectant is known to be useful for maintaining the viral structure and function. In this study, we examined how useful trehalose is as protectant for BV cryopreservation during repeated freeze-thaw cycles: 1) membrane fusion between liposomes (multilamellar vesicles, MLVs) and BVs, 2) infection of insect culture cells (Sf9 cells) by RFP-expressing BVs, and 3) morphologies of these BVs were investigated by fluorescent dequenching assay, fluorescence microscopy, and transmission electron microscopy (TEM), respectively. The results suggest that the BVs deteriorate in quality with each freeze-thaw cycle, and this deterioration can be diminished with the use of trehalose to an extent similar to that seen with storage on ice.
Impact of the non-native locariid fish Pterygoplichthys pardalis in native fish community on a seasonal tropical floodplain in Mexico
Authors: Escalera-Vázquez Luis H. , García-López Jesús E. , Sosa-López Atahualpa , Calderón-Cortés Nancy , Hinojosa-Garro Demián
Published: December 2019

The present study reports the seasonal dynamics of the fish community structure in the presence of a non-native fish (Pterygoplichthys pardalis) in tropical waterbodies of southern Mexico. The studied floodplain existed in both connected pools and disconnected pools “to the Palizada river”. Local fish fauna showed consistent assemblages across seasons, but among the 17 local fish species recorded, the non-native species P. pardalis showed the highest percentage of contribution to the fish community (ca. 20%). Conversely, the frequency of occurrence and density of the non-native species showed variation in relation to the type of waterbody and seasonality; its density was approximately four times higher in disconnected pools than in connected pools in the rainy season and its predominant size class in both pool types was 21-30 cm in standard length. Interestingly, the diversity of the native species was negatively related to the density of the non-native species, indicating that the presence of P. pardalis can be a factor involved in the decline of native fish diversity in these local communities. Currently, the possible impacts of the presence of P. pardalis on local fish diversity at the regional scale are unknown, but our results suggest that hydrological dynamics regulate the establishment of the non-native species in this region. However, future studies are needed to provide insights into the actual scenario of P. pardalis distribution in Yucatan Peninsula and the possible impacts on the native fish fauna in southern Mexico.
The IYPT and the ‘Ring Oiler’ problem
Authors: Plesch Martin , Plesník Samuel , Ružičková Natália
Published: December 2019

The International Young Physicists’ Tournament (IYPT) continued in 2018 in Beijing, China and 2019 in Warsaw, Poland with its 31st and 32nd editions. The IYPT is a modern scientific competition for teams of high school students, also known as the Physics World Cup. It involves long-term theoretical and experimental work focused on solving 17 publicly announced open-ended problems in teams of five. On top of that, teams have to present their solutions in front of other teams and a scientific jury, and get opposed and reviewed by their peers. Here we present a brief information about the competition with a specific focus on one of the IYPT 2018 tasks, the ‘Ring Oiler’. This seemingly simple mechanical problem appeared to be of such a complexity that even the dozens of participating teams and jurying scientists were not able to solve all of its subtleties.
Identification of Subsurface Lithology in Sendang Mulyo, Purwoharjo Village, Samigaluh Subdistrict, Kulon Progo Regency
Authors: Katriani L. , Darmawan D. , Ruwanto B. , Lutfiana H. , Prameswari H H.
Published: December 2019

Research aimed to determining the lithological conditions subsurface of landslide areas in Sendang Mulyo, Purwoharjo Village, Samigaluh Subdistrict, Kulon Progo Regency by geoelectric and microseismic methods. The research had been conducted after knowing the subsurface lithology conditions, it could anticipate landslides as disaster mitigation. The location of research is on a hillside in Purwoharjo Village. The research located on that area because the history landslides. The area is the longest landslide and had a major impact on the villagers that located below the hill. The research used a set of resistivity geoelectric devices with Syscal brands and microseismic devices Digital Portable Seismograph brands TDL-3035 type Taide brands. In geoelectric method used 5 lines, 2 lines 150 m from north to south, 2 lines 120 m and 1 line 100 m from east to west, while the microseismic method used 30 points with spaces of 10-100 meters. The results of the geoelectric method are obtained lithology of clay material with resistivity of 0.16 - 160 Ω.m, sand material with resistivity 160 - 1093 Ω.m, sandstone material with resistivity 1093 - 8000 Ω.m, and a andesite material with resistivity of 8000 - 122165 Ω.m, while the results of the microseismic method obtained clay rock material having a value of Vs
between 406.33 m/s and 742.52 m/s represented by the dark blue spectrum. In the middle landslide has a depth of clay material up to 33 meters. The results showed that subsurface lithology in the area is prone to landslides, because it is suspected that there is a sliding field at a depth of 33 meters. This is supported by the presence of andesite rocks which spread at a depth of 20 meters and above the andesite material, there is clay material that quite thick.
Synthesis and characterization of thymol-loaded lauryl glycol chitosan for pesticide formulation
Authors: Yusoff S N M , Kamari A , Ishak S , Jumadi J , Abdulrasool M M , Kumaran S , Wong S T S
Published: December 2019

Thymol is a hydrophobic active ingredient and widely used as an alternative pesticide for pest control. However, due its low solubility in water, a water-soluble carrier is required in its formulation. Therefore in this study, the potential of an amphiphilic chitosan, namely lauryl glycol chitosan (LGC) as a carrier to encapsulate and release thymol was evaluated. The physical and chemical properties of LGC were characterized using Fourier Transform Infrared (FTIR) Spectrometer, Proton Nuclear Magnetic Resonance (1H NMR) Spectrometer, UV-Visible Spectrophotometer, Thermogravimetric Analyser (TGA) and Transmission Electron Microscope (TEM). A Fluorescence Spectrometer was used to determine the critical micelle concentration (CMC) value of LGC in aqueous solution. The encapsulation efficiency of LGC for thymol was determined by using a High Performance Liquid Chromatography (HPLC). The FTIR and 1H NMR analyses confirmed the structure of the synthesized LGC. It was noted that the addition of lauryl and glycol groups to the chitosan backbone has enhanced the solubility properties of chitosan in neutral and basic media. TEM observation confirmed that LGC could form self-aggregates in the solution with a spherical shape. The CMC value determined for LGC was 0.008 mg/mL. LGC exhibited good affinity towards thymol with an encapsulation efficiency of 58%. The findings from in vitro release study showed that the LGC could prolong the release of thymol from its micelles. Results from this study highlight that LGC possesses great characteristics to be further developed as a promising carrier in the pesticide formulation.
The Potential of Chitosan-TiO2 Nanocomposite for Methyl Orange and Rhodamine B Removal
Authors: Abdulrasool M M , Kamari A , Kumaran S , Ishak S , Yusoff S N M , Jumadi J , Wong S T S
Published: December 2019

The overall objective of present work was to prepare and use chitosan-titanium dioxide (CS-TiO2) nanocomposite as an adsorbent to remove two toxic dyes, namely Methyl Orange (MO) and Rhodamine B (RhB) from the aqueous solution. This work consists of two main parts, namely adsorption and characterization studies. For adsorption studies, several experimental parameters were studied such as the effect of initial concentration, solution pH and adsorbent dosage. Meanwile, Scanning Electron Microscope (SEM), Thermogravimetric Analyser (TGA), and X-ray Diffractometer (XRD) were used for characterization studies. The outcomes have shown that the equilibrium data correlated well to Freundlich isotherm model with adsorption capacity at equilibrium (K
F) was determined as 1.608 mg/g for MO and 7.646 mg/g for RhB, respectively. Based on SEM analysis, the rod- and needle-like deposits on the surface of CS-TiO2 nanocomposite were disappeared following interaction with MO and RhB. There were cube-like deposits observed on the surface of CS-TiO2 nanocomposite after adsorption of MO, while a dense and uneven surface texture were observed after adsorption of RhB. From TGA analysis, CS had two degradation stages, while CS-TiO2 nanocomposite had three steps of decomposition. Furthermore, XRD results observed diffraction peaks for CSTiO2 at 2θ = 34.075°, 29.235°, 25.47° and 20.26°.
Synthesis, Characterisation and Mechanism of Novel Ca-ZSM-5 Zeolite Nanocomposite from Eggshell using Simple Co-Precipitation Method
Authors: Kumaran S , Kamari A , Abdulrasool M M , Wong S T S , Jumadi J , Yusoff S N M , Ishak S
Published: December 2019

In this study, Ca-ZSM-5 zeolite nanocomposite was synthesised as controlled-released fertiliser due to the excess of nutrients leaching in the soil which has caused serious environmental problem such as eutrophication. The zeolite nanocomposite was first synthesised using a simple co-precipitation template method. The zeolite nanocomposite was then impregnated with calcium, originated from chicken eggshell powder, at a molar ratio of 1:1. The physical and chemical properties of Ca-ZSM-5 zeolite nanocomposite were characterised using several analytical instruments such as Fourier Transform Infrared (FTIR) Spectrometer, Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) Spectrometer and Transmission Electron Microscopy (TEM). Based on SEM analysis, the porosity of mesoporous H-ZSM-5 nanozeolite was in the range of 31.7 to 190 nm. Meanwhile, the porosity of macroporous eggshell was 71.4 to 230 nm and mesoporous H-ZSM-5 nanozeolite material was impregnated into the macroporous eggshell due to porosity of eggshell was larger than porosity of H-ZSM-5 nanozeolite. Ca-ZSM-5 zeolite nanocomposite with porosity of 71.4-198 nm was successfully synthesised by simple co-precipitation method. While the results obtained from FTIR analysis confirmed the presence of tetrahedral (TOx, x = Si or Al) stretching. Overall, the synthesised Ca-ZSM-5 zeolite nanocomposite possess key characteristic as a precursor for various applications.
Science generic skills of ‘chemistry’? prospective teachers: A study on collaborative learning using Exe-media
Authors: Harefa N , Suyanti R D
Published: December 2019

Collaborative learning is a learning model that guides students to gather ideas and data to solve common problems. In this study, collaborative learning was integrated with Exe-media on reaction rate and salt hydrolysis to improve prospective teacher generic science skills. Specifically, this study aims to investigate Exe-media effectiveness to improve prospective teacher generic science skill. This study employed methods of a quasi experiment with a nonequivalent control group design. The subject of this research are prospective teachers of class Kim’B as experiment class and Kim’C as control class of Department of Chemistry Education, Faculty of Mathematic and Natural Science, Universitas Negeri Medan. Experiment class received treatment in form of learning used collaborative learning using Exe-media. Control class received treatment in form of learning used conventional model using power point as media. Data was collected through pretest and posttest results from prospective teacher in both classes. A t-test was used and it is found that level of significance is 0.002 (sig. < 0.05) proving that collaborative learning using Exe-media is effective to improve prospective teachers’ generic science skill.
Detection Staphylococcus aureus Producing Enterotoxin A on the Skewers Meatballs Product in Yogyakarta City Indonesia
Authors: Budiarso T Y , Prihatmo G , Restiani R , Pakpahan S , Sari L
Published: December 2019

Meatballs are snacks that are sold by street vendors in the school area and some public places in Yogyakarta city. Based on the materials used and the traditional producing process, it is possible that the hearty snacks can be contaminated by enterotoxin-producing Staphylococcus bacteria. This study aims to detect the presence of enterotoxin-producing Staphylococcus on skewers meatballs. Skewed meatball samples were taken from ten different locations in Yogyakarta city. The samples were grown on the Staphylococcus sp test standard medium, Baird Parker Agar (BPA). The colony candidates were then selected into Mannitol Salt Agar (MSA), carbohydrate fermentation medium, gram staining and then confirmed using the API Staph. Molecular characterization by detecting nuc genes and sea genes as encode enterotoxin A producers. The result of this research showed that the total bacteria ranged from 1.7x104 - 2.0x109 CFU/g. Identification results using API Staph were found as S. aureus, S. cohni, S. xylosus, S. lentus, S. warneri, and S. sciuri while nuc and sea genes were only found in S. aureus.
The Effectiveness of Problem Based Learning in Biology with Fishbone Diagram on Critical Thinking Skill of Senior High School Students
Authors: A Priyadi A. , Suyanto S.
Published: December 2019

This research aims at investigating the effectiveness of Problem Based Learning with Fishbone Diagram on the students’ critical thinking skill in the Biology learning. This research adopted a quasi-experimental design notably pretest-posttest nonequivalent control group design. Population of this research included 73 students of grade X of the State Senior High School 1 of Pundong. The population was taken by using target population, and 49 students were determined as the sample by using random sampling technique. This research adopted critical thinking tests that were administered before and after the learning process took place. The instrument to measure critical thinking skill was a test consisting of 11 items. The instrument was initially validated the expert lecturer (expert judgment) to obtain its content validity and construct validity. Subsequently, empirical validity and instrument reliability were done by using Alpha Cronbach. The data of critical thinking skill were analyzed by using independent sample t-test at the significance level of (α) = 0.05. The result showed the significance value of 0.00<0.05. This study suggests that PBL with FD was effective in developing the students’ critical thinking skill.
The TPACK Analysis of High School Biology Teachers in Sragen Regency, Central Java Based on Teacher Certification Status
Authors: Pradana S. P. , Paidi  , Subali B. , Antony M. K. , Hapsari N. , Astuti F. E. C.
Published: December 2019

Technological Pedagogical and Content Knowledge (TPACK) is the combination of knowledge about PK, CK and TK. The purposes of this study were to find out how the TPACK of high school biology teachers in Sragen Regency and to find out whether there were differences in the TPACK between certified biology teachers and those who were not certified. The type of this research was descriptive research with survey methods. The population in this study was a hypothetical population (the forecast of the population, what the population is expected to be) and the sample representing the population was taken using convenience sampling techniques which included 17 biology teachers spread across 13 high schools in Sragen Regency. Based on the research that has been carried out, the results showed that the knowledge of PCK is very good (85.0%), TCK is poor (47.6%), TPK is fair (64.2%), and TPACK teachers were in a fairly poor category (51.3%). The results also showed that there was no significant difference between the TPACK of certified biology teachers and non-certified biology teachers with a significance value greater than 0.05.
Combination of CPS and SAVI on Biology Learning Media to Improve Student’s Understanding and Creativity on Environmental Change Topic
Authors: Sagita S. G. N. , Aminatun T.
Published: December 2019

The purpose of this research is to determine the feasibility and effectiveness of biology learning media with a combination of CPS and SAVI to improve students’ understanding and creativity. This research was conducted on students of grade X MIPA program in SMA Negeri 7 Purworejo, the subject was selected using Purposive Sampling method. The research method used is Research and Development (R & D) by Dick and Carey’s ADDIE (Analyze, Design, Development, Implementation, and Evaluation) model research. The instruments used were expert judgment feasibility questionnaires, multiple choice questions and student worksheets. Data of the feasibility was analyzed by using percentage. The results indicated that Biology Learning Media with a combination of CPS and SAVI is effective to use shown on (1) expert’s validity percentage which above 75 means that learning media is feasible to use, (2) user response on usability showed that the percentage is 89, 02 means that the learning media is feasible to use, (3) effectiveness of media showed that the N-Gain result is 0, 52 which included on middle category of improving students’ ability, and the results of the student worksheet assessment is 84, 16 which categorized high on students’.