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Single-turn coil (STC) is a destructive pulse magnet aiming at a 100–300 T ultra-high magnetic field. A thermal–electrical coupling model, in which the solid–liquid phase transition process is considered, is proposed. The effects of solid–liquid phase transition on pressure, temperature, and electrical conductivity are investigated. The results show that the compressed and stretched regions coexist simultaneously, and the distribution of both regions changes with time during discharging. Moreover, the region with the highest current density is inside the conductor, since the phase transition reduces the electrical conductivity of the region near the inner surface of STCs. By comparison, the simulation results are highly consistent with the measured data, and the necessity of considering the phase transition process is validated. The results obtained in this work are helpful for understanding the thermodynamic process of STCs during discharge. [ABSTRACT FROM AUTHOR]

Copyright of Umsatzsteuer-Rundschau is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A key challenge currently for the new ferroelectric refrigeration with high efficiency and environmental friendliness lies in the urgent demand for ferroelectric materials with huge electrocaloric effects (ECE). Ferroelectric polycrystalline ceramics with high ECE stand out as one of the most promising candidates for electrocaloric cooling applications. However, the grain boundary network, as a barrier for the cross‐transmission of charged carriers, widely exists in electrocaloric polycrystalline ceramics and is often neglected in favor of focusing more on composition regulation and structural design. Herein, a grain boundary barrier engineering is proposed that regulates the Schottky barrier at the grain boundary network in the Ba0.8Zr0.2TiO3 ceramics by a maneuverable annealing process and clarifies its critical role in enhancing the ECE of polycrystalline ceramics. As a result, a substantial enhancement of the EC performance (from 0.68 to 1.63 K at 50 °C and 80 kV cm−1, ≈2.4 times) has been achieved in the annealed Ba0.8Zr0.2TiO3 ceramics with a lower Schottky barrier. The microstructural and electrical characterization reveals that the lower Schottky barrier in the grain boundary network facilitates the domain switching and electronic transition, hence resulting in enhanced polarization response and EC performance. [ABSTRACT FROM AUTHOR]

This article reports the synthesis, along with structural and photophysical characterization of 2‐(2'‐hydroxyphenyl)benzazole derivatives functionalized with various azaheterocycles (pyridine, pyrimidine, terpyridine). These compounds show dual‐state emission properties, that is intense fluorescence both in solution and in the solid‐state with a range of fluorescent color going from blue to orange. Moreover, the nature of their excited state can be tuned by the presence of external stimuli such as protons or metal cations. In the absence of stimuli, these dyes show emission stemming from anionic species obtained after deprotonation (D* transition), whereas upon protonation or metal chelation, ESIPT process occurs leading to a stabilized and highly emissive K* transition. With the help of extensive ab initio calculations, we confirm that external stimuli can switch the nature of the transitions, making this series of dyes attractive candidates for the development of stimuli‐responsive fluorescent ratiometric probes. [ABSTRACT FROM AUTHOR]

High-conductivity tellurium-based glasses were anticipated to be the attractive candidates in chalcogenide glass systems on account of their distinctive characteristics and extensive application prospects. In this paper, the high-density (>96%) Sn8[(Ga2Te3)34(SnTe)66]92 bulk glass with the density of 5.5917 g/cm3 was successfully prepared by spark plasma sintering (SPS) technology at 460 K, using a 5 min dwell time and 450 MPa pressure. The room-temperature thermal conductivity of Sn8 bulk materials significantly decreased from 1.476 W m−1∙K−1 in the crystalline sample to 0.179 W m−1∙K−1 in the glass, and the Seebeck coefficient obviously increased from 35 μV∙K−1 in to 286 μV∙K−1, indicating that the glass transition of tellurium-based semiconductors could optimize the thermal conductivity and Seebeck coefficient of the materials. Compared to the conventional tellurium-based glassy systems, the fabricated Sn8 bulk glass presented a high room-temperature conductivity (σ = 6.2 S∙m−1) and a large glass transition temperature (Tg = 488 K), which was expected to be a promising thermoelectric material. [ABSTRACT FROM AUTHOR]

This study aims to ameliorate the contribution capability of doubly-fed induction generator (DFIG) to participate in standalone microgrid operation. The islanded microgrid consists of a solar photovoltaic array for solar energy conversion and battery energy storage in addition to DFIG-based wind energy conversion system. Using a simplified control approach, the study describes multi-mode operation of a DFIG-based AC/DC microgrid using a stator-side solid-state transition switch (SSTS). Using SSTS operation, the DFIG stator can be seamlessly disconnected and reconnected from the point of common coupling without interrupting power to the loads in the microgrid. Additionally, non-ideal AC loads can be handled efficiently without the need for computationally exhaustive approaches to enhance stator voltages and currents. [ABSTRACT FROM AUTHOR]

Aqueous fluids are extensively present in the middle to lower crust, as revealed by seismic and magnetotelluric soundings. The α−β quartz phase transition significantly affects many physical properties and leads to substantial microcracks that can provide pathways for the migration of crustal fluids. A systematic investigation of macroscopic physical properties and microstructure of quartz is crucial to elucidate their correlation. In the present study, the effects of water content, trace elements, orientations, and phase transition on the electrical conductivity of quartz were thoroughly evaluated at 400−900°C and 1 GPa. Individual annealing experiments were simultaneously conducted on quartz single crystals at different peak temperatures and 1 GPa to investigate the evolution and spatial distribution of microcracks using X‐ray microtomography (CT) and backscattered electron imaging. We found that trace element content and orientations, rather than H2O, are the dominant factors controlling the conductivity of quartz. The distinct changes in conductivity of single crystals at around α−β phase transition temperature are attributed to the transformation of microcracks from isolated to interconnected networks, as confirmed by two‐dimensional (2‐D) and three‐dimensional (3‐D) microstructure images. Based on the variation in electrical conductivity and microstructure across the transition, it thus is proposed that the intragranular microcracks caused by quartz phase transition can serve as fluid or melt pathways within highly conductive zones present in the middle to lower crust, while α‐quartz acts as an impermeable cap. Plain Language Summary: Numerous geophysical observations have disclosed the widespread presence of aqueous fluids in the middle to lower crust. It has been demonstrated that the α−β quartz phase transition not only causes drastic changes in many physical properties, but also play an important role in fluid storage in crust due to the generation of microcracks. An integrated study on electrical conductivity, X‐ray tomography and backscattered electron images can unravel the correlation of macroscopic physical properties and microstructure of quartz. Our results indicated that orientations and trace element content have predominant influences on the electrical conductivity compared to water content. Additionally, a marked change in the conductivity of quartz single crystals occurred at temperature around the α−β phase transition, which is ascribed to the formation of interconnected microcracks confirmed by 2‐D and 3‐D high‐resolution microstructure images. These intragranular microcracks in quartz can promote porosity and permeability, facilitating the interconnection of fluid or melt required for the highly conductive anomaly in the middle to lower crust, while the α‐quartz above it may serve as a permeability barrier. Key Points: The effects of temperature, trace elements, and orientations on electrical conductivity of quartz were quantitatively evaluatedThe interconnected microcracks formed at α−β quartz phase transition were confirmed by electrical conductivity, 2‐D and 3‐D imagesThe transition‐induced microcracks provide fluid pathways for high conductivity zones in the middle to lower crust [ABSTRACT FROM AUTHOR]

We report an isothermal electric field-induced first-order phase transition from a Mott insulator to the metallic state in the epitaxial thin film of V 2 O 3 in the temperature regime below its Mott transition temperature of ≈ 180 K. This isothermal electric field-induced transition is accompanied by interesting electrothermal history effects, which depend on the measurement paths followed in the electric field–temperature phase space. These interesting properties result in tuneable resistive switching and distinct memristive behaviour in V 2 O 3 . A generalized framework of disorder-influenced first-order phase transition in combination with a resistor network model has been used to explain the observed experimental features. These findings promise possibilities for Mott insulators to be used as highly energy-efficient switches in novel technologies such as neuromorphic computing. [ABSTRACT FROM AUTHOR]

Knowledge of the statics and dynamics of ferroelectric domains is of immense importance since they are directly correlated with macroscopic polarization and strain. For the present work, piezoresponse force microscopy (PFM) is used to afford insight into field-induced phase transitions and local switching properties of a (1–2x)Na0.5Bi0.5TiO3–xBiFeO3–xPbTiO3 system for compositions, x = 0.01, 0.03, 0.05, and 0.07. Rietveld analysis of x-ray diffraction data reveals crystallization of the compound in single and dual phases in the chosen compositions. Upon the application of a local electric field, a phase transition from relaxor to normal ferroelectric (FE) is observed for all samples. A decrease in degree of non-ergodicity is realized within this composition range, which is found by analyzing the stability of field-induced ferroelectric domains. The field-induced FE domains for lower concentrations of x are found to be irreversible and a reversible nature was found for higher values of x. In addition, spatial variations of local switching parameters are investigated with the help of switching spectroscopic-PFM and a maximum local d 33 was found for compositions having dual phases. [ABSTRACT FROM AUTHOR]

Insect developmental transitions are precisely coordinated by ecdysone and juvenile hormone (JH). We previously revealed that accumulated H3K27 trimethylation (H3K27me3) at the locus encoding JH signal transducer Hairy is involved in the larval-pupal transition in insects, but the underlying mechanism remains to be fully defined. Here, we show in Drosophila and Bombyx that Rpd3-mediated H3K27 deacetylation in the prothoracic gland during the last larval instar promotes ecdysone biosynthesis and the larval-pupal transition by enabling H3K27me3 accumulation at the Hairy locus to induce its transcriptional repression. Importantly, we find that the homeodomain transcription factor Schlank acts to switch active H3K27 acetylation (H3K27ac) to repressive H3K27me3 at the Hairy locus by directly binding to the Hairy promoter and then recruiting the histone deacetylase Rpd3 and the histone methyltransferase PRC2 component Su(z)12 through physical interactions. Moreover, Schlank inhibits Hairy transcription to facilitate the larval-pupal transition, and the Schlank signaling cascade is suppressed by JH but regulated in a positive feedback manner by ecdysone. Together, our data uncover that Schlank mediates epigenetic reprogramming of H3K27 modifications in hormone actions during insect developmental transition. [ABSTRACT FROM AUTHOR]

Electrical triggering of a metal-insulator transition (MIT) often results in the formation of characteristic spatial patterns such as a metallic filament percolating through an insulating matrix or an insulating barrier splitting a conducting matrix. When MIT triggering is driven by electrothermal effects, the temperature of the filament or barrier can be substantially higher than the rest of the material. Using X-ray microdiffraction and dark-field X-ray microscopy, we show that electrothermal MIT triggering leads to the development of an inhomogeneous strain profile across the switching device, even when the material does not undergo a pronounced, discontinuous structural transition coinciding with the MIT. Diffraction measurements further reveal evidence of unique features associated with MIT triggering including lattice distortions, tilting, and twinning, which indicate structural nonuniformity of both low-and high-resistance regions inside the switching device. Such lattice deformations do not occur under equilibrium, zero-voltage conditions, highlighting the qualitative difference between states achieved through increasing temperature and applying voltage in nonlinear electrothermal materials. Electrically induced strain, lattice distortions, and twinning could have important contributions in the MIT triggering process and drive the material into nonequilibrium states, providing an unconventional pathway to explore the phase space in strongly correlated electronic systems. [ABSTRACT FROM AUTHOR]

Power transmission and transformation are important parts of power distribution, which is increasingly necessary in modern society; this is particularly important due to the green transition. Consequently, increasing the efficiency of power transformers is a priority to improve the economic and environmental aspects of electrical transformation. Lightweight graphene coatings on transformer wire rods represent a valid solution improving thermoelectrical performances. In this work, a graphene coating was applied by electrophoretic deposition to copper wire rods through a sustainable deposition bath, studying the impact of the deposition current density. The morphology of the coated wire rods, the adhesion of the coating to the substrate, and their thermoelectric properties were evaluated. This work demonstrates the application of EPD to coat copper wire rods with graphene, resulting in a 5.58% reduction in electrical resistivity and an 88% enhancement in thermal performance. In addition, relationships between coating performances and deposition parameters were highlighted. An analysis of variation (ANOVA) confirmed the main role of the current density on the examined outputs. [ABSTRACT FROM AUTHOR]

Dissipative Kerr soliton microcombs in microresonators have enabled fundamental advances in chip-scale precision metrology, communication, spectroscopy, and parallel signal processing. Here we demonstrate polarization-diverse soliton transitions and deterministic switching dynamics of a self-stabilized microcomb in a strongly-coupled dispersion-managed microresonator driven with a single pump laser. The switching dynamics are induced by the differential thermorefractivity between coupled transverse-magnetic and transverse-electric supermodes during the forward-backward pump detunings. The achieved large soliton existence range and deterministic transitions benefit from the switching dynamics, leading to the cross-polarized soliton microcomb formation when driven in the transverse-magnetic supermode of the single resonator. Secondly, we demonstrate two distinct polarization-diverse soliton formation routes – arising from chaotic or periodically-modulated waveforms via pump power selection. Thirdly, to observe the cross-polarized supermode transition dynamics, we develop a parametric temporal magnifier with picosecond resolution, MHz frame rate and sub-ns temporal windows. We construct picosecond temporal transition portraits in 100-ns recording length of the strongly-coupled solitons, mapping the transitions from multiple soliton molecular states to singlet solitons. This study underpins polarization-diverse soliton microcombs for chip-scale ultrashort pulse generation, supporting applications in frequency and precision metrology, communications, spectroscopy and information processing. Thermal Instability hinders reliable generation of dissipative Kerr solitons in Silicon Nitride microresonators. The authors investigate a regime where polarization-diverse soliton transitions and deterministic dynamics of a self-stabilized microcomb in a dispersion managed microresonator driven with a single pump laser. [ABSTRACT FROM AUTHOR]

The interaction between different types of substituents in dicarbollide ligands and their influence on the stabilization of various rotational conformers (rotamers) of transition metal bis(dicarbollide) complexes [3,3′-M(1,2-C2B9H11)2]− are considered. It has been shown that the formation of intramolecular CH···X hydrogen bonds between dicarbollide ligands is determined by the size of the proton acceptor atom X rather than its electronegativity. Due to the stabilization of rotamers with different dipole moments, intramolecular hydrogen bonds between ligands in transition metal bis(dicarbollide) complexes can have a significant impact on the biological properties of their derivatives. In the presence of external complexing metals, weak intramolecular CH···X hydrogen bonds can be broken to form stronger X—>M donor-acceptor bonds. This process is accompanied by the mutual rotation of dicarbollide ligands and can be used in sensors and molecular switches based on transition metal bis(dicarbollide) complexes. [ABSTRACT FROM AUTHOR]

Actively tunable ultrafast broadband terahertz (THz) polarimetry using a reconfigurable phase‐change material holds great potentials and prospects for the achievement of next‐generation versatile integrated THz components and systems in a variety of THz applications. Here, an optically tunable ultrafast broadband THz polarimetric device (THz‐PoD) composed of a phase‐change material Ge2Sb2Te5 (GST) and a thin mica substrate is demonstrated. This proposed novel THz‐PoD is verified for a frequency range of 0.1–2.5 THz, exhibiting broadband and ultrafast determination of polarization states for linearly polarized THz waves at polarization angles from −90° to 90°. It is shown that optical excitation with ns pulses allows easy and efficient control of the polarimetric properties of such THz‐PoD. The essential role of the GST film in switching the phase transition between the amorphous and crystalline phases is emphasized by the theoretical investigation of the optically tunable ultrafast polarimetric mechanism of the device. This phase transition allows optically changing the THz‐PoD's properties by ns‐pulsed laser in a controlled way to achieve THz polarimetry for linearly polarized THz waves. The combined advantages of this strategy can open up a new and promising way for realizing versatile reconfigurable and integrated THz devices, which may further promote the development of novel THz systems and applications. [ABSTRACT FROM AUTHOR]

VS2 and VSe2 have attracted particular attention among the transition metals dichalcogenides because of their promising physical properties concerning magnetic ordering, charge density wave (CDW), emergent superconductivity, etc., which are very sensitive to stoichiometry and dimensionality reduction. Yanson point-contact (PC) spectroscopic study reveals metallic and nonmetallic states in VS2 PCs, as well as a magnetic phase transition, was detected near 20 K. The rare PC spectra, where the magnetic phase transition was not visible, show a broad maximum of around 20 mV, likely connected with electron-phonon interaction (EPI). The PC spectra of VSe2 demonstrate metallic behavior, which allowed us to detect features associated with EPI and CDW transition. The Kondo effect appeared for both compounds, apparently due to interlayer vanadium ions. Besides, the resistive switching was observed in PCs on VSe2 between a low resistive, mainly metallic-type state, and a high resistive nonmetallic-type state by applying bias voltage (about 0.4 V). Reverse switching occurs by applying a voltage of opposite polarity (about 0.4 V). The reason may be the alteration of stoichiometry in the PC core due to the displacement of V ions to interlayer under a high electric field. The observed resistive switching characterizes VSe2 as a potential material, e.g., for non-volatile resistive RAM, neuromorphic engineering, and other nanoelectronic applications. Per contra, VS2 attracts attention as a rare layered van der Waals compound with magnetic transition. [ABSTRACT FROM AUTHOR]

Nowadays, owing to the new technological and industrial requirements for equipment, such as flexibility or multifunctionally, the development of all-solid-state supercapacitors and Li-ion batteries has become a goal for researchers. For these purposes, the composite material approach has been widely proposed due to the promising features of woven carbon fiber as a substrate material for this type of material. Carbon fiber displays excellent mechanical properties, flexibility, and high electrical conductivity, allowing it to act as a substrate and a collector at the same time. However, carbon fiber's energy-storage capability is limited. Several coatings have been proposed for this, with nanostructured transition metal oxides being one of the most popular due to their high theoretical capacity and surface area. In this overview, the main techniques used to achieve these coatings—such as solvothermal synthesis, MOF-derived obtention, and electrochemical deposition—are summarized, as well as the main strategies for alleviating the low electrical conductivity of transition metal oxides, which is the main drawback of these materials. [ABSTRACT FROM AUTHOR]

Nonreciprocal devices, allowing to manipulate one‐way signals, are crucial to quantum information processing and quantum networks. Here a nonlinear cavity‐magnon system is proposed, consisting of a microwave cavity coupled to one or two yttrium–iron–garnet (YIG) spheres supporting magnons with Kerr nonlinearity, to investigate nonreciprocal unconventional photon blockade. The nonreciprocity originates from the direction‐dependent Kerr effect, distinctly different from previous proposals with spinning cavities and dissipative couplings. For a single sphere case, nonreciprocal unconventional photon blockade can be realized by manipulating the nonreciprocal destructive interference between two active paths, via varying the Kerr coefficient from positive to negative, or vice versa. By optimizing the system parameters, the perfect and well‐tuned nonreciprocal unconventional photon blockade can be predicted. For the case of two spheres with opposite Kerr effects, only reciprocal unconventional photon blockade can be observed when two cavity‐magnon coupling strengths Kerr strengths are symmetric. However, when coupling strengths or Kerr strengths become asymmetric, nonreciprocal unconventional photon blockade appears. This implies that two‐sphere nonlinear cavity‐magnon systems can be used to switch the transition between reciprocal and nonreciprocal unconventional photon blockades. This study offers a potential platform for investigating the nonreciprocal photon blockade effect in nonlinear cavity magnonics. [ABSTRACT FROM AUTHOR]

Flexible multiplexing chips that permit reconfigurable multidimensional channel utilization are indispensable for revolutionary 6G terahertz communications, but the insufficient manipulation capability of terahertz waves prevents their practical implementation. Herein, we propose the first experimental demonstration of a flexible multiplexing chip for terahertz communication by revealing the unique mechanism of topological phase (TP) transition and perseveration in a heterogeneously coupled bilayer valley Hall topological photonic system. The synthetic and individual TPs operated in the coupled and decoupled states enable controllable on-chip modular TP transitions and subchannel switching. Two time-frequency interleaved subchannels support 10- and 12-Gbit/s QAM-16 high-speed data streams along corresponding paths over carriers of 120 and 130 GHz with 2.5- and 3-GHz bandwidths, respectively. This work unlocks interlayer heterogeneous TPs for inspiring ingenious on-chip terahertz-wave regulation, allowing functionality-reconfigurable, compactly integrated and CMOS-compatible chips. [ABSTRACT FROM AUTHOR]

Copyright of Socioloski Pregled is the property of Srpsko Sociolosko Drustvo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ternary logic has received substantial attention over binary logic due to diminished delay, reduced power consumption, and minimized area requirements. Carbon Nanotube Field Effect Transistors (CNTFETs) are mostly preferred for the implementation of ternary logic because of their ability to achieve multi-threshold transistors. This paper presents an energy-efficient CNTFET-based 3-trit Wallace tree multiplier design using a novel 4-input ternary adder (called 4-ITA), full-adder, and half-adder. We have proposed half-adder, full-adder, and 1-trit multipliers using a new 3:1 multiplexer module (called MUX-2) that significantly enhances energy efficiency within our ternary multiplier design. This multiplexer, leveraging high and standard threshold voltage devices, greatly optimizes our ternary multiplier's power consumption and computational speed. Furthermore, we reduced power dissipation by minimizing switching transitions within the signal generation circuits of both MUX-2 and the arithmetic modules. All the arithmetic designs were designed using the 45 nm CNTFET technology. Results prove that the 3-trit multiplier achieved 40% lesser power consumption and a 51% power delay product improvement compared to the best literature design. [ABSTRACT FROM AUTHOR]

In this study, the resistive switching phenomena in TiN/Ti/HfO2/Ti metal–insulator–metal stacks is investigated, mainly focusing on the analysis of set and reset transitions. The electrical measurements in a wide temperature range reveal that the switching transitions require less voltage (and thus, less energy) as temperature rises, with the reset process being much more temperature sensitive. The main conduction mechanism in both resistance states is Space-charge-limited Conduction, but the high conductivity state also shows Schottky emission, explaining its temperature dependence. Moreover, the temporal evolution of these transitions reveals clear differences between them, as their current transient response is completely different. While the set is sudden, the reset process development is clearly non-linear, closely resembling a sigmoid function. This asymmetry between switching processes is of extreme importance in the manipulation and control of the multi-level characteristics and has clear implications in the possible applications of resistive switching devices in neuromorphic computing. [ABSTRACT FROM AUTHOR]

The classical model predictive control (MPC) usually aims to minimize the current error at the end of the control period. This method is equivalent to minimizing the current total harmonic distortion (THD) when the control period tends to be infinitely small. However, due to the limitations of hardware in practice, the optimization effect of current THD is not obvious. Aiming at the above problem, an improved double-vector model predictive control method is proposed for the single-phase active-neutral-point-clamped five-level (ANPC-5L) inverter. Two voltage vectors in each control cycle are used in this method to reduce the current THD by minimizing the area enclosed by the actual and reference current. In addition, a capacitor voltage control method is designed for the problem of multiple control objectives coupling in this structure. In this method, an idea of hierarchy is designed for voltage jump and switching transition limits, neutral point (NP) voltage, and flying capacitor (FC) voltage, achieving the effect of weightless factor and good dynamic and static performance. Finally, the effectiveness of the proposed method is verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

The transition from natal downs for heat conservation to juvenile feathers for simple flight is a remarkable environmental adaptation process in avian evolution. However, the underlying epigenetic mechanism for this primary feather transition is mostly unknown. Here we conducted time-ordered gene co-expression network construction, epigenetic analysis, and functional perturbations in developing feather follicles to elucidate four downy-juvenile feather transition events. We report that extracellular matrix reorganization leads to peripheral pulp formation, which mediates epithelial-mesenchymal interactions for branching morphogenesis. α-SMA (ACTA2) compartmentalizes dermal papilla stem cells for feather renewal cycling. LEF1 works as a key hub of Wnt signaling to build rachis and converts radial downy to bilateral symmetry. Novel usage of scale keratins strengthens feather sheath with SOX14 as the epigenetic regulator. We show that this primary feather transition is largely conserved in chicken (precocial) and zebra finch (altricial) and discuss the possibility that this evolutionary adaptation process started in feathered dinosaurs. Natal downs adapted for heat conservation transition to juvenile feathers that support simple flight during bird development. Here the authors characterize gene expression networks and epigenetic changes and use functional perturbations to characterize evolutionarily conserved regulatory switches that control this transition in birds. [ABSTRACT FROM AUTHOR]

This study aimed to examine the stability of depression subtypes over time or the multiple factors and mechanisms that influence these subtypes. Data from two waves of the China Health and Retirement Longitudinal Study (CHARLS) for 2013 (T1) and 2018 (T2), separated by 5 years were included in latent class analysis (LCA) and latent transition analysis (LTA). Specifically, scores on the 10-item Chinese version of the Centre for Epidemiological Studies Depression Scale (CES-D-10) of 2,828 Chinese individuals aged 60 years and older were analyzed. Older Chinese adults were categorized into three classes based on depressive symptoms: the severe depressive symptoms, the mild depressive symptoms, and transition groups. At T2, 70.4% of participants reported severe depressive symptoms, 62.1% reported mild depressive symptoms, and 49.2% were placed in the transition group. Patients in the severe depressive symptoms and mild depressive symptoms tended to switch to the transition group over time, with probabilities of 21.1% and 28.2%, respectively. Further analysis showed that sex, place of residence, marital status, ability to perform activities of daily living (ADLs), self-rated health status, and life satisfaction significantly predicted this transition. This study demonstrated a transition pattern of depressive symptoms in Chinese older adults. We should pay more attention to key elderly groups such as unmarried women, alcohol consumption, and poor self-rated health, rationally plan mental health resources, and establish a dynamic tracking service system to prevent the depression and related adverse consequences. [ABSTRACT FROM AUTHOR]

In the development of silicon photonics, the continued downsizing of photonic integrated circuits will further increase the integration density, which augments the functionality of photonic chips. Compared with the traditional design method, inverse design presents a novel approach for achieving compact photonic devices. However, achieving compact, reconfigurable photonic devices with the inverse design that employs the traditional modulation method exemplified by the thermo-optic effect poses a significant challenge due to the weak modulation capability. Low-loss phase change materials (PCMs) exemplified by Sb2Se3 are a promising candidate for solving this problem benefiting from their high refractive index contrast. In this work, we first developed a robust inverse design method to realize reconfigurable silicon and phase-change materials hybrid photonic devices including mode converter and optical switch. The mode converter exhibits a broadband operation of >100 nm. The optical switch shows an extinction ratio of >25 dB and a multilevel switching of 41 (>5 bits) by simply changing the crystallinity of Sb2Se3. Here, we experimentally demonstrated a Sb2Se3/Si hybrid integrated optical switch for the first time, wherein routing can be switched by the phase transition of the whole Sb2Se3. Our work provides an effective solution for the design of photonic devices that is insensitive to fabrication errors, thereby paving the way for high integration density in future photonic chips. [ABSTRACT FROM AUTHOR]

We studied the phase change and resistive switching characteristics of copper oxide (Cu x O) films through post-thermal annealing. This investigation aimed to assess the material's potential for a variety of electrical devices, exploring its versatility in electronic applications. The Cu x O films deposited by RF magnetron sputtering were annealed at 300, 500, and 700 °C in ambient air for 4 min by rapid thermal annealing (RTA) method, and then it was confirmed that the structural phase change from Cu2O to CuO occurred with increasing annealing temperature. Resistive random-access memory (ReRAM) devices with Au/Cu x O/p+-Si structures were fabricated, and the ReRAM properties appeared in CuO-based devices, while Cu2O ReRAM devices did not exhibit resistive switching behavior. The CuO ReRAM device annealed at 500 °C showed the best properties, with a on/off ratio of 8 × 102, good switching endurance of ∼100 cycles, data retention for 104 s, and stable uniformity in the cumulative probability distribution. This characteristic change could be explained by the difference in the grain size and density of defects between the Cu2O and CuO films. These results demonstrate that superior and stable resistive switching properties of RF-sputtered Cu x O films can be obtained by low-temperature RTA. [ABSTRACT FROM AUTHOR]

In this research work, an independently controlled two output half-bridge resonant LED driver is proposed. Half bridge series converters will be providing power to two LED lamps. The devices in half-bridge converter are switched at zero voltage using LC resonant circuit. Therefore, switching transition power losses are minimized which increases the LED driver efficiency. Each LED lamp's ripple current is decreased by adding an inductor in series with it, eliminating the need for an electrolytic capacitor and extending the life of the resonant LED driver. Both regulating and dimming operations use asymmetrical duty cycle (ADC) control. Numerical simulations are conducted to examine the suggested resonant converter topology's steady state performance as it sources LED applications. Using the OrCAD/PSPICE tool for universal AC mains, 25 W and 29 W LED driver analysis, design, modeling, and simulation are carried out. The proposed driver needs to provide high efficiency even at reduced illumination. [ABSTRACT FROM AUTHOR]

Resistive Random Access Memory (ReRAM) is considered to be a suitable candidate for future memories due to its low operating voltage, fast access speed, and the potential to be scaled down to nanometer range for ultra-high-density storage. In addition, its ability to retain multi-level resistance states makes it suitable for neuromorphic computing applications. In this paper, we report the resistive switching performance of Cu/MgO/Pt ReRAM. Repetitive resistive switching transitions with low switching voltages (around 1 V), 102 storage windows, and multi-level memory capabilities have been obtained. Biological synaptic plasticity behavior, such as long-duration potentiation/depression and paired-pulse facilitation, has been realized by the Cu/MgO/Pt ReRAM. The simulation of convolutional neural network for handwritten digit recognition is carried out to evaluate its potential application in neuromorphic systems. Finally, the conduction mechanism of the device is studied, and a resistive switching model based on Cu conducting filaments is proposed according to the dependence of I–V results on temperature and electrode size as well as the element distribution in the device. These findings indicate the potential of Cu/MgO/Pt device as high-performance nonvolatile memories and its utilization in future computer systems and neuromorphic computing. [ABSTRACT FROM AUTHOR]

We present results from the investigation of a transition between two whistler-mode waves with the same frequency and the parallel wavelength but different perpendicular wavenumbers in the inhomogeneous media consisting of the plasma density and the background magnetic field. We consider transverse inhomogeneities of these quantities. We demonstrate that there are critical values of the plasma density and the magnetic field (which depend on the wave frequency and the parallel wavelength) and the switching between two whistler-mode waves occurs in the vicinity of these values. We analyze this problem assuming that these critical values are reached inside the finite-size transition layer between two regions where all the background quantities are homogeneous. We found analytical criteria for the mode switching and we confirmed our results with time-dependent simulations of the electron-MHD equations describing whistler-mode waves in the magnetospheric plasma. We also investigate numerically the dependency of various parameters of the wave switching on the size of the transition region containing critical values of the plasma density and the magnetic field. [ABSTRACT FROM AUTHOR]

Many complicated dynamical events may be broken down into simpler pieces and efficiently described by a system that shifts among a variety of conditionally dynamical modes. Building on switching linear dynamical systems, we develop a new model that extends the switching linear dynamical systems for better discovering these dynamical modes. In the proposed model, the linear dynamics of latent variables can be described by a higher-order vector autoregressive process, which makes it feasible to evaluate the higher-order dependency relationships in the dynamics. In addition, the transition of switching states is determined by a stick-breaking logistic regression, overcoming the limitation of a restricted geometric state duration and recovering the symmetric dependency between the switching states and the latent variables from asymmetric relationships. Furthermore, logistic regression evidence potentials can appear as conditionally Gaussian potentials by utilizing the Pólya-gamma augmentation strategy. Filtering and smoothing algorithms and Bayesian inference for parameter learning in the proposed model are presented. The utility and versatility of the proposed model are demonstrated on synthetic data and public functional magnetic resonance imaging data. Our model improves the current methods for learning the switching linear dynamical modes, which will facilitate the identification and assessment of the dynamics of complex systems. [ABSTRACT FROM AUTHOR]

The Bangiales represent an ancient lineage within red algae that are characterized by a life history featuring a special transitional stage from diploid to haploid known as the conchosporangia stage. However, the regulatory mechanisms governing the initiation of this stage by changes in environmental conditions are not well understood. This study analyzed the changes in phytohormones and H2O2 content during the development of conchosporangia. It also compared the gene expression changes in the early development of conchosporangia through transcriptome analysis. The findings revealed that H2O2 was shown to be the key signal initiating the transition from conchocelis to conchosporangia in Pyropia haitanensis. Phytohormone analysis showed a significant increase in 1- aminocylopropane-1-carboxylic acid (ACC) levels during conchosporangia maturation, while changes in environmental conditions were found to promote the rapid release of H2O2. H2O2 induction led to conchosporangia development, and ACC enhanced both H2O2 production and conchosporangia development. This promotive effect was inhibited by the NADPH oxidase inhibitor diphenylene iodonium and the H2O2 scavenger N, N'-dimethylthiourea. The balance of oxidative-antioxidative mechanisms was maintained by regulating the activities and transcriptional levels of enzymes involved in H2O2 production and scavenging. Transcriptome analysis in conjunction with evaluation of enzyme and transcription level changes revealed upregulation of protein and sugar synthesis along with modulation of energy supply under the conditions that induced maturation, and exogenous ACC was found to enhance the entire process. Overall, this study demonstrates that ACC enhances H2O2 promotion of the life cycle switch responsible for the transition from a vegetative conchocelis to a meiosispreceding conchosporangia stage in Bangiales species. [ABSTRACT FROM AUTHOR]

Neuromorphic computing has recently emerged as a potential alternative to the conventional von Neumann computer paradigm, which is inherently limited due to its architectural bottleneck. Thus, new artificial components and architectures for brain-inspired computing hardware implementation are required. Bipolar analog memristive devices, whose resistance (or conductance) can be continuously tuned (as a synaptic weight), are potential candidates for artificial synapse applications. In this work, lanthanum nickelate (La2NiO4+ δ , L2NO4), a mixed ionic electronic conducting oxide, is used in combination with TiN and Pt electrodes. The TiN/L2NO4/Pt devices show bipolar resistive switching with gradual transitions both for the SET and RESET processes. The resistance (conductance) can be gradually modulated by the pulse amplitude and duration, showing good data retention characteristics. A linear relationship between the resistance change and total applied pulse duration is experimentally measured. Moreover, synaptic depression and potentiation characteristics, one of the important functions of bio-synapses, are artificially reproduced for these devices, then modeled and successfully tested in a spiking neural network environment. These results indicate the suitability of using TiN/L2NO4/Pt memristive devices as long-term artificial synapses in neuromorphic computing. [ABSTRACT FROM AUTHOR]

The toxicity of botulinum multi-domain neurotoxins (BoNTs) arises from a sequence of molecular events, in which the translocation of the catalytic domain through the membrane of a neurotransmitter vesicle plays a key role. A recent structural study of the translocation domain of BoNTs suggests that the interaction with the membrane is driven by the transition of an α helical switch towards a β hairpin. Atomistic simulations in conjunction with the mesoscopic Twister model are used to investigate the consequences of this proposition for the toxin–membrane interaction. The conformational mobilities of the domain, as well as the effect of the membrane, implicitly examined by comparing water and water–ethanol solvents, lead to the conclusion that the transition of the switch modifies the internal dynamics and the effect of membrane hydrophobicity on the whole protein. The central two α helices, helix 1 and helix 2, forming two coiled-coil motifs, are analyzed using the Twister model, in which the initial deformation of the membrane by the protein is caused by the presence of local torques arising from asymmetric positions of hydrophobic residues. Different torque distributions are observed depending on the switch conformations and permit an origin for the mechanism opening the membrane to be proposed. [ABSTRACT FROM AUTHOR]

In this contribution, we propose a hybrid interaction technique that integrates near-field and object-space interaction techniques for manipulating objects at a distance in virtual reality (VR). The objective of the hybrid interaction technique was to seamlessly leverage the strengths of both the near-field and object-space manipulation techniques. We employed bimanual near-field metaphor with scaled replica (BMSR) as our near-field interaction technique, which enabled us to perform multilevel degrees-of-freedom (DoF) separation transformations, such as 1~3DoF translation, 1~3DoF uniform and anchored scaling, 1DoF and 3DoF rotation, and 6DoF simultaneous translation and rotation, with enhanced depth perception and fine motor control provided by near-field manipulation techniques. The object-space interaction technique we utilized was the classic Scaled HOMER, which is known to be effective and appropriate for coarse transformations in distant object manipulation. In a repeated measures within-subjects evaluation, we empirically evaluated the three interaction techniques for their accuracy, efficiency, and economy of movement in pick-and-place, docking, and tunneling tasks in VR. Our findings revealed that the near-field BMSR technique outperformed the object space Scaled HOMER technique in terms of accuracy and economy of movement, but the participants performed more slowly overall with BMSR. Additionally, our results revealed that the participants preferred to use the hybrid interaction technique, as it allowed them to switch and transition seamlessly between the constituent BMSR and Scaled HOMER interaction techniques, depending on the level of accuracy, precision and efficiency required. [ABSTRACT FROM AUTHOR]

The discovery of ferroelectric hafnium oxide enabled a variety of non-volatile memory devices, like ferroelectric tunnel junctions or field-effect transistors. Reliable application of hafnium oxide based electronics in space or other high-dose environments requires an understanding of how these devices respond to highly ionizing radiation. Here, the effect of 1.6 GeV Au ion irradiation on these devices is explored, revealing a reversible phase transition, as well as a grain fragmentation process. The collected data demonstrate that non-volatile memory devices based on ferroelectric hafnia layers are ideal for applications where excellent radiation hardness is mandatory. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Conserved regulatory switches for the transition from natal down to juvenile feather in birds" published in Nature Communications. The correction addresses errors in Figure 2a of the original article. The errors include an incorrect sample order in the histogram and a superimposed letter on a label. The corrections have been made in both the PDF and HTML versions of the article. The document also includes the names of the authors involved in the study. [Extracted from the article]

Repetitive erasure/creation of conducting domain walls between two parallel/antiparallel domains at bipolar write voltages enables the high storage density of a ferroelectric domain-wall memory. Generally, the domain switching kinetics is described by the Kolmogorov–Avrami–Ishibashi model on the basis of domain nucleation and growth without the consideration of distributive defect pinning energies. Here, mesa-like cells were etched from single-crystal LiNbO3 thin films bonded to SiO2/Si wafers, and Pt metal contacts were deposited at their sides. The abrupt off-to-on current jump occurs at a typical domain switching time for the cell in a lateral size above 111 nm, implying the non-Kolmogorov–Avrami–Ishibashi domain switching kinetics immune to the defect pinning effect. However, the domain switching time has a broad distribution for the cell below 49 nm, implying the defect-controlled domain switching mechanism. A new model is developed to describe the size-driven transition. The reliability tests of the memory show a fast operation speed (<2 ns) and excellent reliability of on/off switching states for mass production. [ABSTRACT FROM AUTHOR]

Microbial systems appear to exhibit a relatively high switching capacity of moving back and forth among few dominant communities (taxon memberships). While this switching behavior has been mainly attributed to random environmental factors, it remains unclear the extent to which internal community dynamics affect the switching capacity of microbial systems. Here, we integrate ecological theory and empirical data to demonstrate that structured community transitions increase the dependency of future communities on the current taxon membership, enhancing the switching capacity of microbial systems. Following a structuralist approach, we propose that each community is feasible within a unique domain in environmental parameter space. Then, structured transitions between any two communities can happen with probability proportional to the size of their feasibility domains and inversely proportional to their distance in environmental parameter space—which can be treated as a special case of the gravity model. We detect two broad classes of systems with structured transitions: one class where switching capacity is high across a wide range of community sizes and another class where switching capacity is high only inside a narrow size range. We corroborate our theory using temporal data of gut and oral microbiota (belonging to class 1) as well as vaginal and ocean microbiota (belonging to class 2). These results reveal that the topology of feasibility domains in environmental parameter space is a relevant property to understand the changing behavior of microbial systems. This knowledge can be potentially used to understand the relevant community size at which internal dynamics can be operating in microbial systems. [ABSTRACT FROM AUTHOR]

In biological or physical systems, the intrinsic properties of oscillators are heterogeneous and correlated. These two characteristics have been empirically validated and have garnered attention in theoretical studies. In this paper, we propose a power-law function existed between the dynamical parameters of the coupled oscillators, which can control discontinuous phase transition switching. Unlike the special designs for the coupling terms, this generalized function within the dynamical term reveals another path for generating the first-order phase transitions. The power-law relationship between dynamic characteristics is reasonable, as observed in empirical studies, such as long-term tremor activity during volcanic eruptions and ion channel characteristics of the Xenopus expression system. Our work expands the conditions that used to be strict for the occurrence of the first-order phase transitions and deepens our understanding of the impact of correlation between intrinsic parameters on phase transitions. We explain the reason why the continuous phase transition switches to the discontinuous phase transition when the control parameter is at a critical value. [ABSTRACT FROM AUTHOR]

Spray coating and vacuum-assisted resin infusion processes were implemented in this work to develop multifunctional biocomposite laminates. The biocomposites were fabricated using a bio-based epoxy resin reinforced with natural sisal fibers coated with graphene nanoplatelets (GNPs). A systematic characterization of material properties was performed to evaluate the mechanical, thermomechanical, electrical, and piezoresistive behavior of biocomposites with different GNPs contents (0, 1, 4, 6, and 8 wt.%). The mechanical tests revealed that adding GNPs to biocomposites has a slight positive effect on their flexural properties compared to the neat biocomposites (without GNPs). The electrical and thermomechanical tests showed that the electrical conductivity and glass transition temperature of biocomposites containing GNPs were enhanced significantly, achieving average values of 5.19 x 10-4 S/m and 63.29°C (26%), respectively. Regarding electromechanical tests, the biocomposites with 8 wt.% GNPs exhibited an excellent piezoresistive behavior under monotonic loading conditions, achieving a gage factor (strain sensitivity) of 3.56. Bending tests with cyclic loading were also performed, and cyclic reproducibility of the piezoresistive response of the biocomposites after 10 cycles was demonstrated, evidencing that the incorporation of GNPs onto sisal fibers by spray-coating produces an effective formation of conductive networks into biocomposites suitable for sensing applications. [ABSTRACT FROM AUTHOR]

A bidirectional dc–dc converter is used to match the voltage levels between a low-voltage battery and a high-voltage traction machine in an electric vehicle. Using a conventional bidirectional converter with a standard voltage range, there is a limitation to the fine variation in the electric vehicle speed. During the regenerative braking process, when the speed decreases below a certain value, the generated voltage is insufficient to charge the battery, hence the regenerated energy cannot be stored. This paper proposes a novel bidirectional converter featuring three distinct operational modes: boost, buck and buck-boost. In the normal driving mode, it operates as a boost converter, providing double gain and accommodating a wide voltage range. During regenerative braking, the proposed converter switches to the buck or buck-boost mode based on the control algorithm. This adaptation is intended to either decrease the generated voltage to charge the battery effectively or to raise the voltage if it is insufficient for charging the battery. This configuration provides voltage stress of half the dc link voltage on the switches. This paper provides a comprehensive analysis of the proposed circuit, a detailed description of the control strategy with pulse generation logic for all switches and a mode transition algorithm. The simulation results of a circuit operating at a 1500 W power level are presented and compared with those of a standard bidirectional converter. [ABSTRACT FROM AUTHOR]

Canoe slalom is an Olympic discipline where athletes race down a whitewater course in kayaks (K1) or canoes (C1) navigating a set of down-stream and upstream gates. Kayak paddles are symmetrical and have a blade at each end, whereas C1 paddles have only one blade that must be moved across the boat to perform strokes on either the right or left side. Asymmetries in paddle force between the two sides of the boat may lead to a reduction in predicted race time. The purpose of this study was to quantify asymmetries in the paddle forces between the two sides for slalom paddling. Paddle forces for 42 canoe slalom athletes (C1 and K1) were quantified from the straight sections of a flat-water figure-of-eight course. Paddle forces were measured using strain gauges embedded in the paddle shaft, stroke type was identified using video, and boat trajectory was tracked using inertial measurement units and high-speed GPS: data were fused using in-house analysis software. Paddle forces were quantified by their peak force, and impulse during the stroke. Paddle forces for the kayakers had asymmetries of 14.2 to 17.1% for the male K1M and 11.1 to 14.4% for the women K1W. Canoeists were no more asymmetrical than the kayakers for their ‘on-side’ strokes between the right and left sides. However, there were considerable differences for their ‘off-side’ strokes: male C1M off-side paddle forces were similar to their ‘on-side’ forces for the same side, but the women C1W had a significantly lower (−20.8% to −29.5%) paddle forces for their ‘off-side’ strokes compared to their ‘on-side’ strokes on that same side. Despite an increasing number of younger male athletes being introduced to the switching technique, and it being used by C1M athletes in international competitions since 2014, C1M paddlers still do not use switching transitions as much as C1W. The data from this study indicate that there is a biomechanical reason for this sex-based difference in the higher proportion of off-side strokes used by the C1M athletes compared to C1W athletes: and this needs to be considered for optimal technique development and race performance. [ABSTRACT FROM AUTHOR]

"Hot spot analysis" was applied to materials from 51 Landsat satellite images using the example of the "Burtinskaya Steppe" area of the Orenburgskii Nature Reserve, to study the dynamics of areas of positive phytomass anomalies relative to a neighborhood with a radius of 300 m. The purpose of this study was to establish the dependence of the variability of areas of increased phytomass on the landscape structure and hydrothermal conditions. The switching of phytocenoses in transition zones from steppe to meadow type of functioning is ensured by varying the ratio of xerophytes and mesophytes depending on fluctuations in the hydrothermal conditions. The frequency and area of positive phytomass anomalies in the bottoms of gullies correlates with their area on partially forested slopes, which indicates the positive role of forest vegetation in the stabilization of moisture influx into the bottoms. In deforested catchment areas of the south-facing slopes, the area of positive phytomass anomalies is determined by the supply of snow moisture, and, in the catchment areas of north-facing slopes, by warm-period precipitation. The binding factors for the most stable positive anomalies of phytomass are the moisture convergence and the landform concavity rather than the catchment area. [ABSTRACT FROM AUTHOR]

This paper studies the networked control system (NCS) with semi-Markov topology switching and network delay. The time delays of the system are considered in the measurement and control channels. The control channel is between the controller and the actuator, the measurement channel is between the sensor and the controller. The topology switching and the transition process among modes are described by semi-Markov sojourn-time probability density function and Markov transition probability matrix respectively. The mean square stability conditions for the networked multi-LSRMs system are obtained by constructing a new Lyapunov function. To ensure the σ -error mean square stability of the closed loop system, a state feedback controller is designed by combining the variation technique of inequalities and Lyapunov stability theory. Finally, several experiments results verify the effectiveness and rationality of the proposed control strategy. • Mathematical modeling of networked semi-Markovian topological switching systems with time delay. • The stability of semi-Markovian jump system is analyzed, and the σ -error mean square stability conditions are presented. • A dual-mode feedback controller is designed based on system topology switching and time delay. • The effectiveness of the proposed control strategy is demonstrated through a multi linear switched reluctance motors system. [ABSTRACT FROM AUTHOR]

The Escherichia coli fumarate and nitrate reduction (FNR) regulator acts as the cell's master switch for the transition between anaerobic and aerobic respiration, controlling the expression of >300 genes in response to O2 availability. Oxygen is perceived through a reaction with FNR's [4Fe-4S] cluster cofactor. In addition to its primary O2 signal, the FNR [4Fe-4S] cluster also reacts with nitric oxide (NO). In response to physiological concentrations of NO, FNR de-represses the transcription of hmp, which encodes a principal NO-detoxifying enzyme, and fails to activate the expression of the nitrate reductase (nar) operon, a significant source of endogenous cellular NO. Here, we show that the L28H variant of FNR, which is much less reactive towards O2 than wild-type FNR, remains highly reactive towards NO. A high resolution structure and molecular dynamics (MD) simulations of the closely related L28H-FNR from Aliivibrio fischeri revealed decreased conformational flexibility of the Cys20-Cys29 cluster-binding loop that is suggested to inhibit outer-sphere O2 reactivity, but only partially impair inner-sphere NO reactivity. Our data provide new insights into the mechanistic basis for how iron–sulfur cluster regulators can distinguish between O2 and NO. [ABSTRACT FROM AUTHOR]

This study investigated users' searching, reading and writing interactions and their activity transitions during task completion process when users were collecting information for learning-related search tasks. Task completion process was defined as the process users started to search till the time when they have collected enough information to accomplish the search tasks. The data analysis was conducted from a new process perspective through synthesising macro- and micro-process levels. Four evenly distributed stages were divided according to the total task completion time in each search session. Our results demonstrated that users generally experienced three sub-processes during task completion process: exploration, accumulation and composition/reporting. Exploration sub-process is basically the first quarter of the total task completion time, during which users often issue more queries and visit more search engine result pages (SERPs) to collect information, and the dominant activity transition is switching between searching and reading; accumulation sub-process is mainly the second and third quarters of the total task completion time, during which they visit more unique content pages, have more revisits per content page, and they switch between reading and writing activities frequently; the last stage is composition/reporting sub-process, which is dominated by writing, and users often switch between writing and reading, and between writing and searching. Based on these findings, we propose a search pace model to describe how users proceed from the beginning to the end of task completion process in these three sub-processes. The methodology applied has been proved to be effective to examine users' interaction behaviours from the process perspective on both the micro- and macro-levels. The findings of this article help us understand how users proceed their dynamic searching, reading and writing behaviours for learning-related tasks, and also have implications for the design of search systems that support learning-related tasks. [ABSTRACT FROM AUTHOR]

We consider the classic stochastic multiarmed bandit problem with a constraint that limits the total cost incurred by switching between actions to be no larger than a given switching budget. For this problem, we prove matching upper and lower bounds on the optimal (i.e., minimax) regret and provide efficient rate-optimal algorithms. Surprisingly, the optimal regret of this problem exhibits a nonconventional growth rate in terms of the time horizon and the number of arms. Consequently, we discover surprising "phase transitions" regarding how the optimal regret rate changes with respect to the switching budget: when the number of arms is fixed, there are equal-length phases, in which the optimal regret rate remains (almost) the same within each phase and exhibits abrupt changes between phases; when the number of arms grows with the time horizon, such abrupt changes become subtler and may disappear, but a generalized notion of phase transitions involving certain new measurements still exists. The results enable us to fully characterize the trade-off between the regret rate and the incurred switching cost in the stochastic multiarmed bandit problem, contributing new insights to this fundamental problem. Under the general switching cost structure, the results reveal interesting connections between bandit problems and graph traversal problems, such as the shortest Hamiltonian path problem. This paper was accepted by J. George Shanthikumar, data science. Supplemental Material: The online appendix and data are available at https://doi.org/10.1287/mnsc.2023.4755. [ABSTRACT FROM AUTHOR]

Mutations highly affect the structural flexibility of two switch domains in M-RAS considered an important target of anticancer drug design. Gaussian accelerated molecular dynamics (GaMD) simulations were applied to probe the effect of mutations P40D, D41E, and P40D/D41E/L51R on the conformational transition of the switch domains from the GTP-bound M-RAS. The analyses of free energy landscapes (FELs) not only reveal that three mutations induce less energetic states than the wild-type (WT) M-RAS but also verify that the switch domains are extremely disordered. Principal component analysis (PCA) and dynamics analysis suggest that three mutations greatly affect collective motions and structural flexibility of the switch domains that mostly overlap with binding regions of M-RAS to its effectors, which in turn disturbs the activity of M-RAS. The analyses of the interaction network between GTP and M-RAS show that the high instability in hydrogen bonding interactions (HBIs) of GTP with residue 41 and Y42 in the switch domain I drives the disordered states of the switch domains. This work is expected to provide a molecular mechanism for deeply understanding the function of M-RAS and future drug design towards the treatment of cancers. [ABSTRACT FROM AUTHOR]