bluuebunny/crossref_metadata_2025 huggingface dataset:
Input effects on the acquisition of variation
Authors: Liégeois Loïc
Published: February 2021

This chapter addresses the acquisition of a
French phonological variable: the schwa ([ə]) in clitics. Our
research is based on data extracted from three longitudinal dense
corpora. The aim is to analyse children’s productions and two types
of adult data: Child and Adult Directed Speech (CDS and ADS,
respectively). The analyses show that schwa alternation is modulated
in CDS, in the sense that parents produce the schwa variant of
clitics significantly more often in CDS. However, differences
between CDS and ADS tend to disappear during the course of language
development. Our results also indicate that the acquisition of schwa
alternation is not homogenous and depends on the clitic used and on
factors linked to characteristics of CDS. These results support
Usage-Based Theories and Construction Grammars frameworks which
assume that CDS properties frame the course of acquisition.
The alternation between standard and vernacular pronouns by
Belgian Dutch parents in child-oriented control acts
Authors: Zenner Eline , Van De Mieroop Dorien
Published: February 2021

This paper studies the social meaning of standard
and vernacular pronouns of address in Dutch by zooming in on the
position they hold in parents’ control acts to their children.
Linking the hyperstandardized linguistic situation in Flanders with
the Western-European ideal of democratic parenting, we expect to
find that the standard forms are more typically connected to more
indirect, softer control acts. This hypothesis is tested through a
mixed method approach, where quantitative and qualitative analyses
are used to chart the choices of ten Belgian Dutch parents when
issuing directives to their children. Studying 452 pronouns we
identify a clear link between the choice of variety and parameters
such as type of control act, repetition, mitigation and boosting and
type of pronoun, with ‘irritation’ as mediating factor.
Testing interface and frequency hypotheses
Authors: Shin Naomi L.
Published: February 2021

The Interface Hypothesis predicts that
syntax-discourse interface features are acquired later than features
involving the interface between syntax and other components of
grammar. The Frequency Hypothesis predicts that frequent grammatical
patterns are acquired earlier than infrequent ones. This study tests
these hypotheses by examining Spanish subject pronoun expression in
interviews with 28 U.S. bilingual children of Mexican-descent.
Binary logistic regression analyses demonstrate that the children’s
pronoun expression is significantly constrained by switch-reference,
a discourse-pragmatic factor, but not tense/mood/aspect, a
morphological factor. These results do not support the Interface
Hypothesis since the children acquire a discourse-pragmatic
constraint before a morphological one. Instead, frequency effects
can explain the findings: the more frequent the constraint, the
earlier it is acquired.
Variation in stress in the Jamaican classroom
Authors: Lacoste Véronique
Published: February 2021

This article investigates how Jamaican
schoolchildren aged 7 respond to their teachers’ production of
stress. Based on a larger sociolinguistic study (Lacoste 2012), the data
concerns particularly the production of a Standard Jamaican English
(SJE) speech pattern that was observed in the classroom setting,
i.e. phonetic exaggeration of the three stress correlates: duration,
pitch and loudness in word-final syllables. Statistical results show
a recurrent use of high levels of the stress correlates including
lengthening of vowels in word-final syllables in the children’s
speech. The lengthening of vowels in word-final position may be
aimed at facilitating the children’s learning of the standard
English variety.
Second language acquisition and dialectal variation in
adults
Authors: Regan Vera
Published: February 2021

This chapter addresses the issue of how the L2 speaker acquires the probabilistic grammar of another language. This implies the related, wider question of whether, as humans, we have some innate knowledge of probabilities and what form such knowledge takes for L2 speakers. The issue is addressed by the description of two studies which provide cross linguistic evidence in relation to one first language group (Polish speakers) and two second languages, (French and Irish English), and which also involve two types of variables, one stable (ne deletion in French) and one in-coming (discourse like in Irish English). Variationist data from these studies suggest that L2 speakers acquire both universal influenced language elements as well as socially conditioned ones and that they approximate both L1 rates and constraint ordering. The chapter links this account of one approach to research on SLA and sociolinguistics with others represented by the contributions which follow in the second section of the volume. These cover a range of areas in variation and L2 acquisition in adults: the acquisition of the categorical vs the probabilistic, the relationship of language change and L2 acquisition, adult dialect acquisition, sociolinguistic competence and Study Abroad,and L2 acquisition and code switching.
Navigating variation amid contested norms and societal
shifts
Authors: Starr Rebecca Lurie , Wang Tianxiao
Published: February 2021

L2 learners acquiring patterns of variation in a
community that uses stigmatized linguistic features face particular
challenges in reconciling prescriptive and local variants. The
present study examines the case of Mandarin in Singapore, in which
transfer from southern Chinese varieties has created a local norm
that differs from the exonormative standard. Speeches from two L2
Mandarin-speaking political figures over a time period from 1966 to
1992 are analyzed, revealing significant roles of L1 background,
education, and stance towards standard language. The language use of
both speakers is found to temporarily increase in standardness in
the years immediately following the launch of the Speak Mandarin
Campaign, a government effort to promote Mandarin as the primary
language of the Chinese Singaporean community.
Usage, evaluation and awareness of French sociolinguistic
variables by second-language learners during a stay abroad
Authors: Gautier Rozenn , Chevrot Jean-Pierre
Published: February 2021

This chapter deals with the acquisition of two
sociolinguistic variables of twenty-nine American and Chinese
learners of French. The purpose is to track the production and
evaluation of the optional liaison and the variable deletion of
negative ne during a 9-month stay abroad (SA) and
to take a close look at the differences between the two
sociolinguistic variables during the course of acquisition. We also
aim to understand whether evaluation and awareness of the usage of
these variables could influence the learners’ production.
Statistical analyses show that the use of formal variants by the
learners declined significantly during their SA. Moreover,
acquisition of the ne variable seems guided by
awareness of its sociolinguistic value, whereas acquisition of
optional liaison appears to be driven by exposure to input and
item-based learning.
The standard-dialect repertoire of second language users in
German-speaking Switzerland
Authors: Ender Andrea
Published: February 2021

The coexistence of dialect and standard language
is a pronounced characteristic of everyday life in the Swiss German
context. This paper examines the linguistic repertoire of second
language users in the Swiss context and how they deal with
dialect-standard variation in a structured interview situation with
a dialect speaker and a standard language speaker. The data from
eight second language users, with English or Turkish as their first
language, illustrate different patterns in the use of dialect,
standard, and a mixture of both codes. Among the eight selected
speakers, high ability to discriminate dialect from standard
language can be observed, and only some L2 users show frequent
mixing of dialect and standard, which violates the strict separation
of the two codes according to L1 speaker norms. Furthermore, the L2
speakers only rarely change their usage of the codes according to
their interlocutor. The results reveal that integrating dialect and
standard language in the L2 repertoire is challenging. L2 users –
depending on their constructed identity within the Swiss German
community and influenced by their L1 social categorization of
codes – compose their linguistic repertoire with more or less
openness to dialect, standard, or integrated use of both codes.
Identity, authenticity and dialect acquisition
Authors: Siegel Jeff
Published: February 2021

The importance of dialect in indexing identity
has been well described for ethnic and regional dialects, such as
African American English (e.g. Rickford & Rickford 2000) and Pittsburghese (e.g.
Johnstone & Kiesling
2008), but not so much for national dialect (although
Portnoy 2011 on
Austrian German is one example). This chapter examines dialect and
national identity, focussing on Australian English, and especially
on accent. It also explores the issues of authenticity, ownership
and legitimacy and their effect on the acquisition of Australian
English by speakers of other dialects, and on second dialect
acquisition in general.
Observing Iran from Baku: Iranian Studies in Soviet and Post-Soviet Azerbaijan
Authors: Gasimov Zaur
Published: February 2021

Azerbaijani national identity emerged in post-Persian Russian-ruled East Caucasia at the end of the nineteenth century, and was finally forged during the early Soviet period. After the fiasco of the short-lived independence period of 1918–20, Azerbaijan became Soviet. Soviet power then instrumentalized Azerbaijan for political and ideological penetration into Iran by galvanizing local separatist movements. Azerbaijani Iranology was shaped within Soviet oriental studies and put into service of Azerbaijani nation-building. Exiled Iranian communists found asylum in Baku, joined local research institutions, wrote the first Persian academic and school textbooks, and contributed to the translation of classic Persian poetry into Azerbaijani. Soviet Azerbaijani Iranologists were sent as translators to the Soviet missions to Iran and Afghanistan. After Azerbaijan regained independence in 1991, its Iranological infrastructure was represented by several departments at the National Academy of Sciences and the Iranian Studies Program at Baku State University. While the number of Persian classes at schools during the last three decades diminished, a new generation of post-Soviet Iranologists—those who studied in Iran—emerged. While Soviet Azerbaijani Iranologists never created a solid bilingual dictionary of Persian, several Persian–Azerbaijani and Azerbaijani–Persian dictionaries were published in the 2010s. Post-Soviet Azerbaijani Iranology is still trying to find its place within humanities in the transitional nation.
Effect of Si and Al on microstructure-property-relationship of Q&P-steels during galvannealing
Authors: Wallner M. , Schneider R. , Steineder K. , Sommitsch C.
Published: February 2021

The influence of a thermal-treatment simulating a galvannealing-process (GA) on the microstructure of a 0.2C–4Mn–1.5Si and 0.2C–4Mn–1.5Al (in wt-%) medium-Mn-Q&P-steel was investigated in detail using dilatometry. After Q&P-process, the retained austenite (RA) fraction is higher and mechanical properties are superior for the Si-concept. Owing to galvannealing, strength decreases substantial for both concepts. For the Si-concept however, RA starts to decompose into pearlite upon galvannealing temperatures of 520°C, leading to a significant decrease in elongation. For the Al-concept, the RA-fraction remains constant up to 560°C, which even results in increased elongations values compared to the galvannealed Si concept. This contribution shows that Al as an alloy-element in Q&P-steel is more suitable for RA stabilisation at higher temperature than Si.
Connectedness in Recovery Narratives of Persons Labeled Not Criminally Responsible: A Qualitative Study
Authors: Aga Natalie , Rowaert Sara , Vander Laenen Freya , Vandevelde Stijn , Vander Beken Tom , Audenaert Kurt , Vanderplasschen Wouter
Published: February 2021

Objective

Connectedness is placed at the heart of the recovery process in mental health care. However, in regard to persons labeled not criminally responsible (NCR), considerations of recovery and connectedness remain in the background. The aim of this study is to understand and explore how individuals labeled not criminally responsible experience connectedness.

Research method

Sixty-seven in-depth interviews were examined and thematically analyzed.

Results

Interviews revealed emotional, functional and personal connectedness as categories of connectedness, each with different qualitative determinants.

Conclusion

This study shows that connectedness should be considered as an essential ingredient of the recovery process by practitioners as well as policy makers. We recommend a shift from an individualistic, punitive approach toward a recovery-supportive rhetoric and more ‘shared decision making’ between service users and providers at all levels.
Final report of the new BIPM comparison BIPM.RI(II)-K1.Ra-223 of activity measurements of the radionuclide 223Ra including the 2014 result of the NPL (United Kingdom), the 2014 result of the PTB (Germany) and the 2018 result of the LNE-LNHB (France)
Authors: Michotte C , Courte S , Nonis M , Coulon R , Judge S , Ratel G , Fréchou C , Cassette P , Keightley J , Kossert K , Nähle O
Published: February 2021

Main text

Since 2014, 3 laboratories have submitted 3 samples of 223Ra to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ra-223. The NPL (United Kingdom), the PTB (Germany) and the LNE-LNHB (France) participated in the comparison and the key comparison reference value (KCRV) has been calculated for the first time. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Breaking the warp barrier: hyper-fast solitons in Einstein–Maxwell-plasma theory
Authors: Lentz Erik W
Published: February 2021

Solitons in space-time capable of transporting time-like observers at superluminal speeds have long been tied to violations of the weak, strong, and dominant energy conditions of general relativity. The negative-energy sources required for these solitons must be created through energy-intensive uncertainty principle processes as no such classical source is known in particle physics. This paper overcomes this barrier by constructing a class of soliton solutions that are capable of superluminal motion and sourced by purely positive energy densities. The solitons are also shown to be capable of being sourced from the stress–energy of a conducting plasma and classical electromagnetic fields. This is the first example of hyper-fast solitons resulting from known and familiar sources, reopening the discussion of superluminal mechanisms rooted in conventional physics.
Interferometric extraction of photoionization-path amplitudes and phases from time-dependent multiconfiguration self-consistent-field simulations
Authors: Orimo Yuki , Tugs Oyunbileg , Sato Takeshi , You Daehyun , Ueda Kiyoshi , Ishikawa Kenichi L
Published: February 2021

Bichromatic extreme-ultraviolet pulses from a seeded free-electron laser enable us to measure photoelectron angular distribution (PAD) as a function of the relative phase between the different wavelength components. The time-dependent multiconfiguration self-consistent-field (TD-MCSCF) methods are powerful multielectron computation methods to accurately simulate such photoionization dynamics from the first principles. Here, we propose a method to evaluate the amplitude and phase of each ionization path, which completely determines the photoionization processes, using TD-MCSCF simulation results. The idea is to exploit the capability of TD-MCSCF to calculate the partial wave amplitudes specified by the azimuthal and magnetic angular momenta (l, m) and the m-resolved PAD. The phases of the ionization paths as well as the amplitudes of the paths resulting in the same (l, m) are obtained through global fitting of the expression of the asymmetry parameters to the calculated m-resolved PAD, which depends on the relative phase of the bichromatic field. We apply the present method to ionization of Ne by combined fundamental and second-harmonic extreme ultraviolet pulses, demonstrating that the extracted amplitudes and phases excellently reproduce the asymmetry parameters.
Filamentary surface plasma discharge flow length and time scales
Authors: Rajendran Lalit K , Singh Bhavini , Vlachos Pavlos P , Bane Sally P M
Published: February 2021

Nanosecond surface dielectric barrier discharges (ns-SDBDs) are a class of plasma actuators that utilize a high-voltage pulse of nanosecond duration between two surface-mounted electrodes to create an electrical breakdown of air, along with rapid heating. These actuators usually produce multiple filaments when operated at high pulse frequencies, and the rapid heating leads to the formation of shock waves and complex flow fields. In this work we replicate a single filament of the ns-SDBDs and characterize the induced flow using velocity measurements from particle image velocimetry and density measurements from background-oriented schlieren. The discharge is produced by a high voltage electrical pulse between two copper electrodes on an acrylic base. A hot gas kernel characterizes the flow field formed close to the electrodes that expands and cools over time and a vortex ring that propagates away from the surface while entraining cold ambient fluid. The gas density deficit inside the kernel displays a power-law decay over time. Based on the observations, we develop a simplified theoretical model based on vortex-driven cooling and perform a scaling analysis to obtain the induced flow length and time scales. The results show that the cooling process’s time scales correspond to a circulation-based time scale of the vortex ring, and the length scale of the kernel corresponds to the vortex ring radius. These findings can guide the choice of optimal filament spacing and pulse frequencies in the design, deployment, and operation of ns-SDBDs for flow control.
Generalized perfect optical vortices along arbitrary trajectories
Authors: Chen Yue , Wang Tingchang , Ren Yuxuan , Fang Zhaoxiang , Ding Guangrui , He Liqun , Lu Rongde , Huang Kun
Published: February 2021

Perfect optical vortices (POVs) arevortex beams with infinitely narrow rings and fixed radii independent of their topological charges. Here we propose the concept of generalized POVs (GPOVs) along arbitrary curves beyond the regular shapes of circles and ellipses. GPOVs share similar properties to POVs, such as defined only along infinitely narrow curves and owning topological charges independent of scale. Using a rigorous mathematical derivation in a curvilinear coordinate, we reveal theoretically that the GPOVs have a topological charge proportional to the area of the swept sector in tracing the curve, suggesting a unique mode for optical vortex beams. Experimentally, the complex-amplitude masks to generate the GPOVs are realized by using a pure-amplitude digital micro-mirror device with the super-pixel encoding technique. The phase profiles of the generated GPOVs are retrieved experimentally through self-built interferometry and exhibit good agreement with the simulations. We also derive a properly modified formula to yield the intensity-uniform GPOVs along predesigned curves, which might find applications in optical tweezers and communications.
Oxidation-induced structural transition of two-dimensional iron oxide on Au(111)
Authors: Li Yangsheng , Zhao Xinfei , Cui Yi , Yang Fan , Bao Xinhe
Published: February 2021

Understanding the dynamic changes of catalytically active nanostructures (NSs) under reaction conditions is a pivotal challenge in catalysis research, which has been intensively studied on metal catalysts, but less on oxide NSs. Here, we synthesized two-dimensional (2D) FeO NSs and thin films on Au(111) and studied their oxidation process in O2 from ultrahigh vacuum to near-ambient-pressure (NAP) conditions, using the combination of in-situ NAP scanning tunneling microscopy and x-ray photoelectron spectroscopy. Our studies revealed atomic details on the transition process from the FeO bilayer to the FeO2 tri-layer on Au(111). Further, we found FeO2 NSs and thin layers are metastable on Au(111) and would undergo a three-dimensional phase change upon further thermal treatments. Our study has thus provided insight on the structural dynamics of 2D iron oxide under reaction conditions and enabled further understanding on the design of the oxide-metal interface.
Local insight to the structural phase transition sequence of Bi2Se3 under quasi-hydrostatic and nonhydrostatic pressure
Authors: Hao Xingyu , Zhu Hailiang , Guo Zhiying , Li Haijing , Gong Yu , Chen Dongliang
Published: February 2021

High-pressure behaviors of Bi2Se3, as one of layered 3D topological insulators, has attracted tremendous interest recent years. However, the phase transition sequence of Bi2Se3 remain controversial. In this work, we explore the structural phase sequence of topological insulator Bi2Se3 using high-pressure x-ray absorption fine structure (XAFS) spectroscopy under quasi-hydrostatic and nonhydrostatic pressure up to 42 GPa. By examining the XAFS features, we find that the appearance of C2/c phase of Bi2Se3 is strongly dependent on pressure condition, C2/c phase of Bi2Se3 only exists under quasi-hydrostatic pressure condition. The phonon dispersion calculations also show that C2/c phase is dynamic unstable. Furthermore, we confirm that Bi2Se3 possesses I4/mmm phase rather than Im-3m and 9/10-fold C2/m phase at high pressure. Combining the experimental and theoretical results, we determine the structural phase transition sequence for Bi2Se3 of R-3m → C2/m → C2/c → I4/mmm phase under quasi-hydrostatic pressure condition and R-3m → C2/m → I4/mmm phase under nonhydrostatic pressure condition. The dynamic unstability and pressure condition sensitivity of C2/c phase may be account for the absence of C2/c phase in the phase transition sequence under nonhydrostatic pressure condition. Our findings obtain the high-pressure phase transition sequences of Bi2Se3 under hydrostatic and nonhydrostatic pressure condition, which can facilitate researchers to explore the novel properties in layered 3D topological insulators.
Giant Goos–Hänchen-like shifts at the merging point in strained graphene double barriers
Authors: Setare M R , Ghasemian Kh , Jahani D
Published: February 2021

Tunneling and the Goos–Hänchen-like (GHL) shifts of quasiparticles through double rectangular potential barriers in mono-layer graphene under uniaxial strain were considered. Expressions for the transmission coefficient and the lateral shift of the transferred beam were obtained by considering the boundary conditions and the stationary phase method, respectively. Moreover, the numerical results of the transmission probability and the lateral shifts for three values of the merging parameter, δ were presented. It was observed, for two values of δ, very large shifts could be obtained and we found the demeanor of the GHL shift is adjustable by changing parameters and is influenced strongly by δ. Finally, our calculations were examined by the limit condition in accordance with the results obtained for a single barrier in presence of the strong uniaxial strain.
Theoretical study of tunable magnetism of two-dimensional MnSe2 through strain, charge, and defect
Authors: Xie Wen-Qiang , Lu Zhi-Wei , He Chang-Chun , Yang Xiao-Bao , Zhao Yu-Jun
Published: February 2021

Two-dimensional transition metal dichalcogenide MnSe2 (2D-MnSe2) with Curie temperature approximate to 300 K has a significant spintronic application on thin-film devices. We demonstrate theoretically a tunable magnetic transition of 2D-MnSe2 between anti-ferromagnetic (AFM) metal and ferromagnetic (FM) half metal as strain increasing. Mechanism of that transition involves a competition between d–p–d through-bond and d–d direct interaction in 2D-MnSe2. Hole doping is an alternative way to enhance the stability of FM coupling. Adsorption (including Li, Na, Cl and F) and vacancy (Mn and Se) studies confirm that the controllable magnetism of 2D-MnSe2 is related to both interaction competition and charge doping. Tensile strains can greatly amplify through-bond interaction and exchange parameters, resulting in a sharp increase of Curie temperature.
Microstructure of quasi-one-dimensional superconductor KCr3As3 prepared by K-ion deintercalation
Authors: Zhang Lu , Li Jun , Mu Qingge , Liu Tong , Yang Dong , Zhu Chunhui , Ren Zhi-an , Tian Huanfang , Li Zi-an , Li Jianqi , Yang Huaixin
Published: February 2021

The microstructure of quasi-one-dimensional KCr3As3 (133) superconductors, which were prepared by chemical cation deintercalation from their counterpart K2Cr3As3 (233) compounds, are investigated using scanning transmission electron microscopy. The nominal KCr3As3 crystals generally exhibit irregular nanoscale 133-phase domains accompanied by an amorphous As-deficient phase and cracks as a result of alkali cation deintercalation processes. Analysis of local defective structures reveals the existence of an intermediate state in the transformation from 233 to 133 phase and a possible K-deficient 233-type structure as a nanoscale cluster. Our microscopic investigations offer insight into the microstructure of KCr3As3 and the alkali metal cation deintercalation processes.
Characterization of mechanical deformation in aluminum by optical second harmonic generation
Authors: Rellaford Kaylee N , Averett Shawn C , Farnsworth Alexander J , Adams Derrik D , Smith Scott D , Fullwood David T , Patterson James E
Published: February 2021

Second harmonic generation (SHG), a laser-based surface technique, was used to characterize near-surface defect evolution associated with mechanical deformation in 2024-T3 aluminum due to tensile loads. Electron backscatter diffraction (EBSD) measurements were also performed to determine the geometrically necessary dislocation density before and after tensile deformation. Comparison of the EBSD and SHG results found that dislocation density and SHG signal are inversely proportional; tensile deformation in the plastic regime led to an increase in dislocation density and a decrease in SHG response. A similar trend was seen in the SHG results on as-received (unpolished) Al samples; SHG response decreases with extent of plastic deformation. This study suggests that SHG has potential as a nondestructive evaluation technique.
Verification of KURBUC-based ion track structure mode for proton and carbon ions in the PHITS code
Authors: Matsuya Yusuke , Kai Takeshi , Sato Tatsuhiko , Liamsuwan Thiansin , Sasaki Kohei , Nikjoo Hooshang
Published: February 2021

The particle and heavy ion transport code system (PHITS) is a general-purpose Monte Carlo radiation transport simulation code. It has the ability to handle diverse particle types over a wide range of energy. The latest PHITS development enables the generation of track structure for proton and carbon ions (1H+, 12C6+) based on the algorithms in the KURBUC code, which is considered as one of the most verified track-structure codes worldwide. This ion track-structure mode is referred to as the PHITS-KURBUC mode. In this study, the range, radial dose distributions, and microdosimetric distributions were calculated using the PHITS-KURBUC mode. Subsequently, they were compared with the corresponding data obtained from the original KURBUC and from other studies. These comparative studies confirm the successful inclusion of the KURBUC code in the PHITS code. As results of the synergistic effect between the macroscopic and microscopic radiation transport codes, this implementation enabled the detailed calculation of the microdosimetric and nanodosimetric quantities under complex radiation fields, such as proton beam therapy with the spread-out Bragg peak.
Background impurities in a delta-doped QW. Part II: Edge doping
Authors: Akimov V , Tulupenko V , Duque C A , Morales A L , Demediuk R , Tiutiunnyk A , Laroze D , Kovalov V , Sushchenko D
Published: February 2021

This is the second part of our study of the background impurity influence on the intersubband energy structure of a single SiGe/Si/SiGe quantum well with the impurity delta layer within the well. By the background impurity we mean sparse shallow donor doping throughout the infinitely wide barriers. In this part we consider a situation where the delta layer is positioned near the edge of the well and the structure symmetry is broken. We explain in detail the necessary modifications of our self-consistent method that includes calculation of impurity binding energy. The results particularly show that the mentioned asymmetry combined with the background impurity in the barriers provides new features to the effect of tuning the intersubband optical transitions by the ionization grade of the impurity in delta-layer that provides new technological possibilities.
Experimental investigation on the performance degradations of the GaN class-F power amplifier under humidity conditions
Authors: Zhou Shaohua
Published: February 2021

To investigate the humidity dependency of the specifications for a GaN class-F power amplifier (PA), humidity experiments are conducted in the Vötsch Industrietechnik SC3 1000 MHG environmental test chamber. The experimental results show that the key specifications of the PA, such as the output power and power-added efficiency, the large-signal gain, and the drain current show degradation as humidity increases. The reason for this degradation may be the reduction of the 2DEG mobility density due to surface degradation at AlGaN recess regions caused by diffusion phenomena of Ga, and Al. The results concluded here would be helpful for the PA designers to understand the humidity effects on the key specifications for the GaN class-F PA comprehensively, so that the designers could consider the effects on the design cycle of the compensation circuits in advance.
A cubic B-spline collocation method with new approximation for the numerical treatment of the heat equation with classical and non-classical boundary conditions
Authors: Tassaddiq Asifa , Yaseen Muhammad , Yousaf Aatika , Srivastava Rekha
Published: February 2021

In this paper, a cubic B-spline collocation method equipped with new approximations for second-order derivatives is used to approximate the solution of the heat equation. This technique depends on the typical finite difference scheme to discretize the time derivative while cubic B-splines are utilized as interpolation functions in the space dimension. The key advantage of using this approach is that the solution is obtained as a piecewise continuous function empowering one to find approximation at any desired location of the domain. The stability and convergence analysis of the presented method are studied rigorously. The capability of the scheme is checked by some test problems. The effectiveness and exactness of the proposed method are confirmed by computing the error norms. Numerical results are contrasted with some existing numerical schemes to exhibit the predominance of our scheme.
Modulation instability of ion-acoustic waves and exchange interaction in magnetized quantum plasma with relative density effects of spin-up and spin-down electrons
Authors: Gul Nabi , Ahmad Rashid
Published: February 2021

The separate-spin evolution quantum hydrodynamic (SSE-QHD) model is used to study Ion-Acoustic Waves (IAWs) in a magnetized quantum plasma having electrons with different spin populations in the presence of the spin particle exchange interactions (Coulomb type) in spin-down electrons only. The plasma consists of inertia-less separated spin-up and spin-down electrons states, while ions are inertial and classical. Besides, a uniform magnetic field is assumed to be directed in the Z-direction i.e.

B

⃗

=

B

0

z

ˆ

. An interesting interplay between exchange interaction and density polarization ratio κ has been observed on dispersive properties, effective Debye screening length and effective ion-acoustic speed. The non-linear Schrödinger equation is derived through a reductive perturbation approach. Moreover, the modulation instability condition and resulting envelope waves are analyzed. The parametric effects of density polarization ratio κ and Coulomb exchange interaction on dispersion, effective screening length, effective ion-acoustic speed, instability growth rate, and on the solitons profile have been discussed in detail. This model can be helpful to study properties of the dilute magnetic semiconductors and degenerate 2D & 3D Fermi electron gas, where exchange interactions are significant.
Neuroprotective effect of hypoxic preconditioning and neuronal activation in a in vitro human model of the ischemic penumbra
Authors: Pires Monteiro Sara , Voogd Eva , Muzzi Lorenzo , De Vecchis Gianmarco , Mossink Britt , Levers Marloes , Hassink Gerco , Van Putten Michel , Le Feber Joost , Hofmeijer Jeannette , Frega Monica
Published: February 2021

Objective. In ischemic stroke, treatments to protect neurons from irreversible damage are urgently needed. Studies in animal models have shown that neuroprotective treatments targeting neuronal silencing improve brain recovery, but in clinical trials none of these were effective in patients. This failure of translation poses doubts on the real efficacy of treatments tested and on the validity of animal models for human stroke. Here, we established a human neuronal model of the ischemic penumbra by using human induced pluripotent stem cells and we provided an in-depth characterization of neuronal responses to hypoxia and treatment strategies at the network level.
Approach. We generated neurons from induced pluripotent stem cells derived from healthy donor and we cultured them on micro-electrode arrays. We measured the electrophysiological activity of human neuronal networks under controlled hypoxic conditions. We tested the effect of different treatment strategies on neuronal network functionality.
Main results. Human neuronal networks are vulnerable to hypoxia reflected by a decrease in activity and synchronicity under low oxygen conditions. We observe that full, partial or absent recovery depend on the timing of re-oxygenation and we provide a critical time threshold that, if crossed, is associated with irreversible impairments. We found that hypoxic preconditioning improves resistance to a second hypoxic insult. Finally, in contrast to previously tested, ineffective treatments, we show that stimulatory treatments counteracting neuronal silencing during hypoxia, such as optogenetic stimulation, are neuroprotective.
Significance. We presented a human neuronal model of the ischemic penumbra and we provided insights that may offer the basis for novel therapeutic approaches for patients after stroke. The use of human neurons might improve drug discovery and translation of findings to patients and might open new perspectives for personalized investigations.
The impact of ELM mitigation on tungsten source in the EAST divertor
Authors: Chen X.H. , Ding F. , Wang L. , Sun Y.W. , Ding R. , Brezinsek S. , Zang Q. , Wang Y.M. , Duan Y.M. , Zhang L. , Hu Z.H. , Zhang Q. , Ye D.W. , Luo Y. , Meng L.Y. , Liu J.B. , Yang Z.S. , Xu G.S. , Liang Y.F. , Luo G.-N. , Ding H.B. , Hu J.S.
Published: February 2021

Divertor tungsten (W) erosion source during edge localized mode (ELM) bursts in EAST is investigated based on optical emission spectroscopy on atomic neutral tungsten line emission at 400.9 nm. Both temporal evolution and total source strength are analyzed and compared in three different ELM mitigation schemes including natural ELMs, resonant magnetic perturbations (RMP) and 2.45 GHz lower hybrid wave (LHW). The mitigation of W source caused by single ELM impact at the divertor target is mainly attributed to the reduction of the W source production in the ELM decay phase. However, with the increase of ELM frequency, the time-averaged intra-ELM W source during an ELM cycle rises and dominates the evolution of the total W source with increasing fraction, which exhibits strong correlation with the core W level in the RMP scheme. In the natural ELM scheme, the pedestal electron temperature is found not only to control the effective W sputtering yield at target during ELMs, thus influencing the intra-ELM W source, but also to be related to the delay time between the divertor ELM WI emission and the core extreme ultraviolet bolometer (XUV) signal which can scale with the parallel ion transit time. Furthermore, the delay time is found to have more consistent dependence on the pedestal plasma collisionality. The rise time of intra-ELM WI emission increases when RMP or LHW is applied, revealing a different ELM mitigation mechanism in comparison with the natural ELM scheme. The temporal profiles of the intra-ELM WI emission in different ELM mitigation schemes are compared and the potential mechanism is discussed. Besides, the ELM mitigation effects with RMP are found to be asymmetric at the outer and inner divertor targets, which is characterized by the different variations of the intra-ELM W source strength and the rise time of WI emission with the ramp-up of RMP coil current. Divertor partial detachment is achieved simultaneously with strong ELM mitigation under a suitable RMP phase difference without additional gas puff.
A mathematical modelling and numerical simulation of the SIRS political fanaticism figure voters model with presence of media in Indonesian presidential election
Authors: Yong B
Published: February 2021

In presidential election, the presidential candidates who will be standing in it should try to get as much support among the voters. Understanding the dynamics of voters spread help presidential candidates or parties which supporting the candidates in designing appropriate strategies to win presidential election. In this paper, the dynamics of voters is described by using a mathematical model of the SIRS deterministic model. The model is constructed as a three-dimensional form of the non-linear differential equation. The spread of voters can move from neutral voters to supportive voters, neutral voters to apathetic voters, supportive voters to apathetic voters, or apathetic voters to neutral voters. Since presidential candidates need media to get the exposure they need to win the elections, we also consider its dynamics with the presence of media to estimate the number of votes in Indonesian presidential election. From the mathematical analysis of the model, we find the political fanaticism figure voters free equilibrium state explicitly and the political fanaticism figure voters endemic equilibrium state implicitly. Sufficient conditions for their existence and local stability of both equilibrium states are derived. Numerical simulation using R based on data from The General Election Commission are carried out to verify the analytical results.
Cyber Insurance Rate Making Based on Markov Model for Regular Networks Topology
Authors: Antonio Y , Indratno S W
Published: February 2021

Computers and Internet play a key role in the processes of data transaction, data exchange and data storage in a business. Malicious software or computer viruses is one of the biggest threats that can attack computer networks and cause huge losses due to loss of data and information. As a way to transfer risk, cyber insurance requires precise and appropriate calculations even though many challenges are faced including the effects of differences in network structure. Standards of cyber insurance that have not been established as in the mortality table for life insurance open the possibility to set a standard calculation based on network structure by determining cyber insurance rates. This study uses a general susceptible-infectious-susceptible model with Markovian property to simulate the process of spreading computer virus and calculate the total loss for each computer. Rate making will consider the number of infected neighbours on a node as an exposure to set insurance rates on regular network topology. The simulation process shows that the rates at each node are affected by the probability of initial infection, the degree of each node on the network, and the parameters of infection or recovery.
SEIR Model and Simulation for Typus Disease
Authors: Side S , Badwi N , Abdy M , Sanusi W
Published: February 2021

The objectives of this research are to obtain a mathematical model for the spread of typhoid by including the factor of flies and food as variables in the model; analyze and simulation models that will provide predictions and status of typhoid. The data used are secondary data on the number of Typhus cases in Makassar City, analysis of the model is done using the lyapunov function method, while the simulation uses the MatLab model. The results of this study are the SEIR model for typhoid spread, then the simulation results of the model using secondary data on the number of typhoid cases in the city of Makassar provide the number of typhus sufferers and the status of typhoid in Makassar city that is disease free or endemic. Prediction of the number of typhoid cases which can be a reference in the early steps of typhoid cases in Makassar.
Mathematical Modelling for Event Occurrence Rainbow Secondary
Authors: Rifandy M , Rahmawati  , Side S
Published: February 2021

Secondary rainbow is a rainbow that formed because light is reflected twice when entering the rain drops and looks right out over the primary rainbow. Rules to formation of the secondary rainbow is same as the primary rainbow when it rains coincide with the sun shining from the other side and the observer is between them. The aims of research are: determine the mathematical model of the secondary rainbow, determine the angle, and the angle secondary rainbow colors using differential calculus. This observation method using literature study which is based on the theoretical framework underlying the ways of solving the problems that include, derivatives, maximum/minimum value, and the properties of light. The results of this research is deviation angle of the mathematical models secondary rainbow;

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1

−
6

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u

sin

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1

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. This model found the optimum angle of the I V
na )) secondary rainbow is 51 °. Large corner secondary rainbow of colors Red, Orange, Yellow, Green, Blue, Indigo and Violet are respectively 50.57, 51.12, 51.72, 52.42, 52.78, 53.45 and 53.60 (in degrees). It is shown that large rainbow angle for each colors of secondary rainbow are different, it is explains that the secondary rainbow is composed of seven colors.
A Regression-Based Approach for Mediation Analysis with Censored Data
Authors: Salehah N A , Suhartono
Published: February 2021

The regression method is one of the most applied approaches to estimate the direct and indirect effect of the causal variable (X) to an outcome (Y) with any mediating variable (M) in their mechanism. Censored or limited data on any one of the inputs, mediators, and output often observed in a randomized trial with a specific follow-up time or with certain conditions and limitations caused by a particular setting. In this study, several regression strategies were employed to estimate each different path parameter, i.e., the effect of X on M(a), the effect of M on Y (b), and the effect of X on Y (c’) for a single mediator model. A simulation study was conducted under various conditions to assess the performance of the proposed strategy while dealing with a censored mediator. A continuous mediator and outcome are observed in this study so that the product method can be applied to understand the estimation of the indirect effect. Based on the results, it is clearly shown that a higher censoring percentage in the mediating variable yields higher bias estimate. By applying Tobit model in M-regression can minimize the bias of estimate effect with higher censoring percentage. Furthermore, it can conclude that the proposed strategy can effectively perform the estimation of indirect effect with a censored mediator.
A Hybrid Generalized Space-Time Autoregressive-Elman Recurrent Neural Network Model for Forecasting Space-Time Data with Exogenous Variables
Authors: Setyowati E , Suhartono  , Prastyo D D
Published: February 2021

This research proposes a hybrid method by combining Generalized Space-Time Autoregressive with exogenous variables and Elman Recurrent Neural Network (GSTARX-Elman RNN) to forecast space-time data. GSTAR method is used for modeling and forecasting multivariate data which including time and location factors. The modeling GSTAR with exogenous variables is to capture time series factors, i.e., trend, seasonal, and calendar variation. This method combines with Elman RNN as a nonlinear forecasting method for the data that have a nonlinear pattern. Hybrid GSTARX-Elman RNN compares with time series regression and GSTARX methods based on RMSE criteria. This research focused on simulation data that consist of a trend, seasonal, and calendar variation patterns, and using two scenarios of noise, i.e., linear and nonlinear noise. The result of these simulations showed that time series regression and GSTARX method could capture well the exogenous variables, but hybrid GSTARX-Elman RNN is a more accurate method than others. Hybrid GSTARX-Elman RNN could capture nonlinearity data pattern from these simulations. In general, the hybrid models tend to provide more accurate forecast performance than individual forecast models that it is in line with the results of the M4 forecasting competition.
Bivariate Poisson Inverse Gaussian Regression Model with Exposure Variable: Infant and Maternal Death Case Study
Authors: Mardalena S , Purhadi  , Purnomo J T D , Prastyo D D
Published: February 2021

One of appropriate methods that could be used to model positive integers response and its corresponding predictors is Poisson regression. This method has a strict assumption to be achieved, that is the mean and variance of response variable must be equal (equidispersion). In many practical issues, sometimes, the variance is larger than the mean (overdispersion). Bivariate Poisson Inverse Gaussian Regression (BPIGR) is proposed to overcome the overdispersion issue. In this study, the BPIGR model is developed by adding the exposure variable as the weight of each sample unit. This study applies the proposed method to model the infant and maternal death data (as the responses) and the factors that influence them. The data of East Java 2017 are used for the application. Maximum Likelihood Estimation (MLE) method is used to estimate the parameters, while the hypothesis testing of the BPIGR model is derived using Maximum Likelihood Ratio Test (MLRT) approach. The results showed that the BPIGR model is a proper model for modeling the number of infant and maternal deaths. Furthermore, all predictor variables significantly influence those two responses.