Earlier Work Research Articles

Multistate Compound Magnetic Tunnel Junction Synapses for Digital Recognition.

The quest to mimic the multistate synapses for bioinspired computing has triggered nascent research that leverages the well-established magnetic tunnel junction (MTJ) technology. Early works on the spin transfer torque MTJ-based artificial neural network (ANN) are susceptible to poor thermal reliability, high latency, and high critical current densities. Meanwhile, work on spin-orbit torque (SOT) MTJ-based ANN mainly utilized domain wall motion, which yields negligibly small readout signals differentiating consecutive states and has designs that are incompatible with technological scale-up. Here, we propose a multistate device concept built upon a compound MTJ consisting of multiple SOT-MTJs (number of MTJs, n = 1-4) on a shared write channel, mimicking the spin-based ANN. The n + 1 resistance states representing varying synaptic weights can be tuned by varying the voltage pulses (±1.5-1.8 V), pulse duration (100-300 ns), and applied in-plane fields (5.5-10.5 mT). A large TMR difference of more than 13.6% is observed between two consecutive states for the 4-cell compound MTJ, a 4-fold improvement from reported state-of-the-art spin-based synaptic devices. The ANN built upon the compound MTJ shows high learning accuracy for digital recognition tasks with incremental states and retraining, achieving test accuracy as high as 95.75% in the 4-cell compound MTJ. These results provide an industry-compatible platform to integrate these multistate SOT-MTJ synapses directly into neuromorphic architecture for in-memory and unconventional computing applications.

On quasicomplete k$k$‐surfaces in 3‐dimensional space‐forms

AbstractIn the study of immersed surfaces of constant positive extrinsic curvature in space‐forms, it is natural to substitute completeness for a weaker property, which we here call quasicompleteness. We determine the global geometry of such surfaces under the hypotheses of quasicompleteness. In particular, we show that, for , the only quasicomplete immersed surfaces of constant extrinsic curvature equal to in the 3‐dimensional space‐form of constant sectional curvature equal to are the geodesic spheres. Together with earlier work of the author, this completes the classification of quasicomplete immersed surfaces of constant positive extrinsic curvature in 3‐dimensional space‐forms.

Chemical mechanical polishing for indium bond pad damascene processing

We investigated chemical mechanical polishing (CMP) of indium, with the goal of obtaining indium bond pads for later cryo-3D integration of quantum computing-related chips, through bonding between these bond pads and indium bumps. Higher removal rates were obtained with soft CMP pads than with hard pads. The latter led to deep scratching, while this effect was much more limited for soft pad CMP. On patterned wafers, indium is cleared well in structured areas using soft pad CMP, leading to relatively high-quality indium surfaces inside bond pads, although corrosion might be of some concern. Pattern density uniformity was an important factor for within-die deviation in indium clearing time. Dishing was much more limited than in earlier work on indium polishing, while surface roughness was also found to be relatively limited. The obtained indium damascene bond pads may be suitable for 3D die-to-die and wafer-to-wafer bonding through indium pad-to-bump bonding.

A Source Identification Problem in a Bi-parabolic Equation: Convergence Rates and Some Optimal Results

This paper is concerned with identification of a spatial source function from final time observation in a bi-parabolic equation, where the full source function is assumed to be a product of time dependent and a space dependent function. Due to the ill-posedness of the problem, recently some authors have employed different regularization method and analysed the convergence rates. But, to the best of our knowledge, the quasi-reversibility method is not explored yet, and thus we study that in this paper. As an important implication, the Hölder rates for the apriori and aposteriori error estimates obtained in this paper improve upon the rates obtained in earlier works. Also, in some cases we show that the rates obtained are of optimal order. Further, this work seems to be the first one that has broaden the applicability of the problem by allowing the time dependent component of the source function to change sign. To the best of our knowledge, the earlier known work assumed the fixed sign of the time dependent component by assuming some bounded below condition.

A generating absorbing boundary condition for simulating wave interaction with maritime structures in current or at forward speed

The lack of suitable boundary conditions in practical surface wave simulations with maritime structures in current or at forward speed may cause energy in the computational domain to accumulate due to spurious wave reflection. The common way to prevent wave reflection is to use passive wave absorbers, such as damping zones or relaxation zones, which requires larger domains at the cost of computational effort. Our goal is to derive a local generating absorbing boundary condition (GABC) for long-crested irregular waves on top of a mean flow, using the flow to model the forward speed of a structure such as a ship. Earlier work has demonstrated that a local GABC for free surface waves has a performance similar to passive wave absorbers, but at a reduced computational effort. New in the present work is that we extend, verify and validate the GABC in the presence of a nonzero mean flow. The GABC is designed to be accurate for a range of wave components in irregular sea states, with the resulting reflection coefficients for each component lower than a chosen value, say 5%. Having used potential flow theory for its derivation means that the boundary should not be placed at the exact location where wave breaking is expected, such as very close to the structure in the domain, or in the surf zone in coastal modeling. For the application with ships in this article that does not pose a limitation. The performance is demonstrated for a range of dimensionless wave number between 0 and 6. Such a boundary condition is obtained through a rational approximation of the linear dispersion relation with a mean flow, in combination with vertical derivatives of the solution variables along the boundary. Local linearization means that the GABC incorrectly considers bound, nonlinear wave components to be freely propagating wave components. Bound components, however, tend to have smaller amplitudes and do not appear to affect performance for the considered cases. Results of simulations with regular and irregular waves, on top of flows with different magnitudes and directions, are found to agree with the theory. The main source of differences is the implementation of the second derivate in the GABC near the free surface. Simulations of a Wigley hull at forward speed in irregular waves are compared to an experiment that was conducted specifically for validating the ABC. The data of the experiment are available as open data through doi: 10.4121/21320604. The comparison between simulation and experiment demonstrates that the GABC with a mean flow can be applied not only for theoretical simulations with propagating waves, but also for more practical applications with a structure in the domain.

Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats

The characteristics of excess aerobic granular sludge, related to its structure and chemical composition, limit the efficiency of anaerobic digestion. For this reason, pre-treatment methods and compositions with other organic substrates are used. In earlier work, no attempt was made to intensify the methane fermentation of the excess aerobic granular sludge by adding fatty waste materials. The aim of the research was to determine the effects of co-digestion of pre-hydrodynamically cavitated aerobic granular sludge with waste fats on the efficiency of methane fermentation under mesophilic and thermophilic conditions. The addition of waste fats improved the C/N ratio and increased its value to 19. Under mesophilic conditions, the highest effects were observed when the proportion of volatile solids from waste fats was 25%. The amount of biogas produced increased by 17.85% and CH4 by 19.85% compared to the control. The greatest effects were observed in thermophilic anaerobic digestion at 55 °C, where a 15% waste fat content in volatile solids was ensured. This resulted in the production of 1278.2 ± 40.2 mL/gVS biogas and 889.4 ± 29.7 mL/gVS CH4. The CH4 content of the biogas was 69.6 ± 1.3%. The increase in biogas and CH4 yield compared to pure aerobic granular sludge anaerobic digestion was 34.4% and 40.1%, respectively. An increase in the proportion of waste fats in the substrate had no significant effect on the efficiency of methane fermentation. Strong positive correlations (R2 > 0.9) were observed between biogas and CH4 production and the C/N ratio and VS concentration.

Modality matters: Three auditory conflict tasks to measure individual differences in attention control.

Early work on selective attention used auditory-based tasks, such as dichotic listening, to shed light on capacity limitations and individual differences in these limitations. Today, there is great interest in individual differences in attentional abilities, but the field has shifted towards visual-modality tasks. Furthermore, most conflict-based tests of attention control lack reliability due to low signal-to-noise ratios and the use of difference scores. Critically, it is unclear to what extent attention control generalizes across sensory modalities, and without reliable auditory-based tests, an answer to this question will remain elusive. To this end, we developed three auditory-based tests of attention control that use an adaptive response deadline (DL) to account for speed-accuracy trade-offs: Auditory Simon DL, Auditory Flanker DL, and Auditory Stroop DL. In a large sample (N = 316), we investigated the psychometric properties of the three auditory conflict tasks, tested whether attention control is better modeled as a unitary factor or modality-specific factors, and estimated the extent to which unique variance in modality-specific factors contributed incrementally to the prediction of dichotic listening and multitasking performance. Our analyses indicated that the auditory conflict tasks have strong psychometric properties and demonstrate convergent validity with visual tests of attention control. Auditory and visual attention control factors were highly correlated (r = .81)-even after controlling for perceptual processing speed (r = .75). Modality-specific attention control factors accounted for unique variance in modality-matched criterion measures, but the majority of the explained variance was modality-general. The results suggest an interplay between modality-general attention control and modality-specific processing.

Frontal midline theta transcranial alternating current stimulation enhances early consolidation of episodic memory

Evidence implicating theta rhythms in declarative memory encoding and retrieval, together with the notion that both retrieval and consolidation involve memory reinstatement or replay, suggests that post-learning theta rhythm modulation can promote early consolidation of newly formed memories. Building on earlier work employing theta neurofeedback, we examined whether theta-frequency transcranial alternating stimulation (tACS) can engender effective consolidation of newly formed episodic memories, compared with beta frequency stimulation or sham control conditions. We compared midline frontal and posterior parietal theta stimulation montages and examined whether benefits to memory of theta upregulation are attributable to consolidation rather than to retrieval processes by using a washout period to eliminate tACS after-effects between stimulation and memory assessment. Four groups of participants viewed object pictures followed by a free recall test during three study-test cycles. They then engaged in tACS (frontal theta montage/parietal theta montage/frontal beta montage/sham) for a period of 20 min, followed by a 2-h break. Free recall assessments were conducted after the break, 24 h later, and 7 days later. Frontal midline theta-tACS induced significant off-line retrieval gains at all assessment time points relative to all other conditions. This indicates that theta upregulation provides optimal conditions for the consolidation of episodic memory, independent of mental-state strategies.

Review of Solvation Studies of Copper (1) Complexes in Different Solvents and at Different Temperatures

The study of the solvation behavior of copper (1) complexes in the mixed solvents has generated a great interest in the field of chemistry. Copper complexes have attracted wide attention due to their important role in analytical chemistry, organic synthesis, metallurgy and medicines etc. Nevertheless, during recent years there has been an increasing interest in the behavior of copper (1) complexes in aqueous and non-aqueous solvents with a view to investigate ion-ion and ion solvent or solute solute interactions under varied conditions. The solvation behavior of some copper(I) perchlorate complexes in binary mixtures of dimethylsulfoxide with dimethylacetamide and dimethylformamide at 298k, and Some Copper(I) Nitrate Complexes in Dimethylsulfoxide and Nitromethane at 298 K and copper sulfate have been measured in binary mixtures of aqueous–methanol mixtures at different temperatures is studied by a combined approach using Molar conductance, ultrasonic velocity and density data, or limiting molar conductance (Λ0), the association constants (KA) respectively . This study is a condensed version of earlier work in the same fields. Keywords: solvation, Molar conductance, Copper sulfate, copper(I) perchlorate

Lie symmetries, solitary wave solutions, and conservation laws of coupled KdV‐mKdV equation for internal gravity waves

The propagation of nonlinear solitary and shallow water waves can be examined by nonlinear evolution equations. The dynamics of nonlinear behavior are described by exact solutions having parametric functions. The integrability of nonlinear equation discloses various characteristics of real phenomenon with continuous and fluctuating background. This work aims to generate symmetry reductions and exact solutions of KdV‐mKdV equation, which is a completely integrable system of nonlinear equations and describes combined solitary wave effects in inhomogeneous medium. The infinitesimal generators and their commutative relations are deduced under invariance property of Lie groups. The invariance property provides a symmetry reduction of governing system. Therefore, a continuous process of reductions transmutes the KdV‐mKdV equation to an equivalent system of ODEs. This system of ODEs leads to the exact solutions involving several arbitrary constants and functions. Such obtained results are generalized than earlier works and never reported in literature. Furthermore, adjoint equation and conserved quantities associated with Lagrangian formulation are constructed under Lie symmetries. To reveal the significance of governing phenomenon, the exact solutions are traced via numerical simulation and thus the graphical structures demonstrate line multisoliton, single soliton, lumps, parabolic and stationary wave profiles.

Evaluating The Real Cost Digital and Social Media Campaign: Longitudinal Effects of Campaign Exposure on E-cigarette Beliefs.

Over the past decade, youth e-cigarette use has risen exponentially. At the same time, digital media use increased markedly while the use of traditional broadcast TV declined. In response, the U.S. Food and Drug Administration's The Real Cost public education campaign shifted to communicating the harms of e-cigarette via primarily digital and social platforms. This study evaluated longitudinal associations between exposure to campaign advertisements and changes in campaign-specific beliefs among US youth. A nationally representative longitudinal cohort of youth (aged 11-16 years at baseline) was surveyed five times. Building on earlier work, we analyzed data from the last three waves (April-July 2020; January-April 2021; and August-October 2021; N = 2625). We assessed self-reported exposure to six ads and agreement with 11 beliefs that were each targeted by one or more ads. Eleven weighted panel regression models assessed whether ad exposure predicted changes in campaign-specific beliefs over time. We observed significant associations between ad exposure and increases in at least one campaign-specific belief for five of the six ads. Across the 11 beliefs, we observed associations between increased exposure and increases in 6 beliefs related to e-cigarettes and toxic metals, lung damage, dangerous ingredients, anxiety, cigarette use, and disappointing important people. We found evidence that self-reported exposure to this digital and social media campaign was successful at influencing youth, providing support for the effectiveness of the campaign's adaption to address youth's changes in tobacco and media use habits. The Food and Drug Administration's The Real Cost public education campaign educates youth about the dangers of e-cigarette use. This study evaluates longitudinal associations between exposure to The Real Cost's advertisements and changes in campaign-specific beliefs among youth. Considering evolving trends in youth media consumption, the campaign adapted its media approach to increase delivery across digital and social media platforms. Our findings indicate that the campaign reached its intended audience and increased youth beliefs around the harm of e-cigarettes and the consequences of e-cigarette use, offering evidence for the effectiveness of digital and social media youth prevention efforts within a fragmented digital environment.

Apriorics: Information and Graphs in the Description of the Fundamental Particles—A Mathematical Proof

In our earlier work, we suggested an axiomatic framework for deducing the fundamental entities which constitute the building block of the elementary particles in physics. The basic concept of this theory, named apriorics, is the ontological structure (OS)—an undirected simple graph satisfying specified conditions. The vertices of this graph represent the fundamental entities (FEs), its edges are binary compounds of the FEs (which are the fundamental bosons and fermions), and the structures constituting more than two connected vertices are composite particles. The objective of this paper is to focus the attention on several mathematical theorems and ideas associated with such graphs of order n, including their enumeration, showing what is the information content of apriorics.

Revisiting column selectivity choices in ultra-high performance liquid chromatography–Using multidimensional analytical Design Spaces to identify column equivalency

Current guides and column selection system (CSS) platforms can provide some helpful insights with regard to the selection of alternative phases. Their practical reliability however, can also turn out to be questionable, especially considering the lack of detailed specifics, such as a clear definition of points of equivalence—appropriate running conditions under which the given analytical mixture can be satisfactorily resolved on various stationary phases. In this context, the use of multivariate modeling tools can be highly beneficial. These tools, when applied systematically, are ideal for uniquely characterizing complex LC-separation systems, a fact supported by numerous peer-reviewed papers.Revisiting our earlier work [1] and the applied systematic workflow [2], we used a Design Space modeling software (DryLab), with the main focus on building and comparing 3-dimensional separation models of amlodipine and its related impurities to identify shared method conditions under which columns are conveniently interchangeable. Our study comprised 5, C18-modified ultra-high performance liquid chromatography (UHPLC) columns in total, in some cases with surprising results. We identified several equivalences between the Design Spaces (DSs) of markedly different columns. Conversely, there were cases where, despite the predicted similarities in column data, the modeled DSs demonstrated clear differences between the selected stationary phases.

Owning a Room of One’s Own: On the Female Self-Construction in All Passion Spent

All Passion Spent is British novelist Vita Sackville-West’s masterpiece, an early work that embodies feminist ideas by telling the story of eighty-eight-year-old Mrs Slane, who rejects her children’s arrangement after her husband’s death and insists on choosing to live alone in a house of her own. The novel demonstrates how women under the patriarchal system are gradually being othered, as well as to get rid of this predicament, and explores the way out for women’s freedom and liberation. This work has been hailed as the novel version of the feminist manifesto A Room of One’s Own. The article mainly focuses on three aspects, namely the loss of the female self, the reconstruction of the female self and the inheritance of the female self in All Passion Spent, to explore the feminist thoughts in this novel. Vita not only intends to dig out the material and spiritual dilemmas faced by women but also her exploration and construction of female subjective status and female self, which provides women with a certain amount of spiritual power to know themselves, remake themselves, and realize their self-worth.

Fractional order uncertain BAM neural networks with mixed time delays: An existence and Quasi-uniform stability analysis

This research investigates the presence of unique solutions and quasi-uniform stability for a class of fractional-order uncertain BAM neural networks utilizing the Banach fixed point concept, the contraction mapping principle, and analysis techniques. In order to guarantee the equilibrium point of fractional-order BAM neural networks with undetermined parameters, some new adequate criteria are devised, and both time delays result in quasi-uniform stability. The acquired results, which are simple to verify in practice, enhance and extend several earlier research works in some ways. Finally, two illustrative examples are provided to show the value of the suggested outcomes.

A66 EFFECTS OF HYMENOLEPIS DIMINUTA EXTRACELLULAR VESICLES ON MOUSE MACROPHAGES AND THEIR MITOCHONDRIA

Abstract Background In recent years, extracellular vesicles (EVs) have emerged as important means of intercellular communication and immune modulation between helminth and host. Earlier work revealed that excretory/secretory products from the rat tapeworm Hymenolepis diminuta (HES) have anti-inflammatory properties when applied to macrophages. In this study, we have investigated the immunomodulatory properties of H. diminuta EVs (HEVs) on macrophages. Aims 1. To isolate and characterize bacterial contaminant-free H. diminuta EVs (Hd-EVs). 2. To determine the effects of Hd-EVs on murine macrophage metabolism and LPS-evoked cytokine production. Methods Adult H. diminuta were cultured for 6h in serum-free RMPI and Hd-EVs isolated from the conditioned medium using an exoEasy kit. Hd-EV protein content was measured using a micro-BCA kit, and size and quantity were measured using Nanosight tracking analysis. Murine bone marrow-derived macrophages or the human macrophage THP-1 cell line were treated with LPS (10 ng/ml) ± a crude H. diminuta extract (HdE), HES, or Hd-EVs for 24h. TNF-α levels in the culture medium was measured by ELISA. Macrophage oxidative phosphorylation (OX.PHOS) and glycolysis were measured in real-time using an Agilent Seahorse XF Analyzer. Results Analysis of 14 Hd-EV samples revealed 4.1 X 109 - 5.48 X 1010 particles/mL, with Hd-EVs predominantly 100-350 nm in diameter and with a protein content of 64.9-181.6 ng/mL. HdE and HES reduced TNF-α production in LPS-activated macrophages by 39-76% (n=11), while Hd-EVs did not lower TNF-α production. Metabolic analysis suggests that HES and Hd-EVs can up-regulate macrophage glycolysis, while only Hd-EVs exposed macrophages showed increased OX.PHOS (n=6). Conclusions We have successfully isolated and begun to characterize EVs from adult H. diminuta. Despite the known abilities of HES, we unexpectedly noted that exposure to Hd-EVs did not result in a statistically significant decrease in macrophage TNF-α release. However, the increase in OX.PHOS macrophages treated with Hd-EVs is something to examine further. The next steps are to determine the contents and immunomodulatory activity of the Hd-EVs, thus advancing knowledge of how helminths can manipulate their hosts. Funding Agencies NSERC Clinical Practice

Novel approach for designing order parameters of clathrate hydrate structures by graph neural network.

Clathrate hydrates continue to be the focus of active research efforts due to their use in energy resources, transportation, and storage-related applications. Therefore, it is crucial to define their essential characteristics from a molecular standpoint. Understanding molecular structure in particular is crucial because it aids in understanding the mechanisms that lead to the formation or dissociation of clathrate hydrates. In the past, a wide variety of order parameters have been employed to classify and evaluate hydrate structures. An alternative approach to inventing bespoke order parameters is to apply machine learning techniques to automatically generate effective order parameters. In earlier work, we suggested a method for automatically designing novel parameters for ice and liquid water structures with Graph Neural Networks (GNNs). In this work, we use a GNN to implement our method, which can independently produce feature representations of the molecular structures. By using the TeaNet-type model in our method, it is possible to directly learn the molecular geometry and topology. This enables us to build novel parameters without prior knowledge of suitable order parameters for the structure type, discover structural differences, and classify molecular structures with high accuracy. We use this approach to classify the structures of clathrate hydrate structures: sI, sII, and sH. This innovative approach provides an appealing and highly accurate replacement for the traditional order parameters. Furthermore, our method makes clear the process of automatically designing a universal parameter for liquid water, ice, and clathrate hydrate to analyze their structures and phases.

Montreal Cognitive Assessment test: Psychometric analysis of a South African workplace sample

The Montreal Cognitive Assessment (MoCA) test is a widely used tool to screen for mild neurocognitive impairment. However, its structural validity has not been fully described in South Africa. The study aimed to replicate and extend earlier work with South African samples, to provide an expanded description of the psychometric properties of the MoCA. The study examined the MoCA in a sample of neurocognitively healthy working adults (N = 402) and individuals diagnosed with mild neurocognitive disorders (N = 42); both groups reported good English proficiency. Analysis included general scale descriptions, and structural and discriminant validity. Age and language, but not gender, influenced MoCA scores, with mean total scores of healthy individuals falling below the universal cut-off. Structural analysis showed that a multidimensional model with a higher-order general factor fit the data well, and measurement invariance for gender and language was confirmed. Discriminant validity was supported, and receiver operating characteristics curve analysis illustrated the potential for grey-zone lower and upper thresholds to identify risk.Contribution: This study replicated previous findings on the effects of age, language and gender, and challenged the universal application of ≤ 26 as cut-off for cognitive impairment indiscriminately across groups or contexts. It emphasised the need for context-specific adaptation in cognitive assessments, especially for non-English first language speakers, to enhance practical utility. Novel to this study, it extended knowledge on the structural validity of the test and introduced grey-zone scores as a potential guide to the identification of risk in resource-restricted settings.

Thermodynamically extended symplectic numerical simulation of viscoelastic, thermal expansion and heat conduction phenomena in solids

AbstractSymplectic numerical schemes for reversible dynamical systems predict the solution reliably over large times as well, and are a good starting point for extension to schemes for simulating irreversible situations like viscoelastic wave propagation and heat conduction coupled via thermal expansion occuring in rocks, plastics, biological samples etc. Dissipation error (artificial nonpreservation of energies and amplitudes) of the numerical solution should be as small as possible since it should not be confused with the real dissipation occurring in the irreversible system. In addition, the other well-known numerical artefact, dispersion error (artificial oscillations emerging at sharp changes), should also be minimal to avoid confusion with the true wavy behavior. The continuum thermodynamical aspects (respect for balances with fluxes, systematic constitutive relationships between intensive quantities and fluxes, the second law of thermodynamics with positive definite entropy production, and the spacetime-based kinematic viewpoint) prove valuable for obtaining such extended schemes and for monitoring the solutions. Generalizing earlier works in this direction, here, we establish and investigate such a numerical scheme for one-dimensional viscoelastic wave propagation in the presence of heat conduction coupled via thermal expansion, demonstrating long-term reliability and the applicability of thermodynamics-based quantities in supervising the quality of the solution.

Non-preservation of α-concavity for the porous medium equation

We show that the porous medium equation does not in general preserve α-concavity of the pressure for 0≤α<1/2 or 1/2<α≤1. In particular, this resolves an open problem of Vázquez on whether concavity of pressure is preserved by the porous medium equation. Our results strengthen an earlier work of Ishige-Salani, who considered the case of small α>0. Since Daskalopoulos-Hamilton-Lee showed that 1/2-concavity is preserved, our result is sharp.Our explicit examples show that concavity can be instantaneously broken at an interior point of the support of the initial data. For 0≤α<1/2, we give another set of examples to show that concavity can be broken at a boundary point.