Change In Moment Research Articles

Older Adults’ Descendants and Family Networks in the Context of Global Educational Expansion

AbstractFamily networks are key to understanding the well‐being of older adults because kin provide instrumental and financial support, help manage health and disability, and encourage social integration. Two momentous societal changes have shaped the families of contemporary older adults: the first and second demographic transitions and global educational expansion. The intersection of these two processes raises questions about how older adults are faring in terms of their kin availability. This paper examines the socioeconomic bifurcation of adults in midlife and beyond in terms of the existence of descendants and other kin. Disparities in kin availability may vary across socioeconomic status and contexts, and so we examine this phenomenon worldwide, analyzing data on two thirds of the world's population of adults aged 50 and above. Our results highlight different kin structures by socioeconomic status. High socioeconomic status adults have fewer descendants but a higher likelihood of having at least one child with tertiary education, a partner, and living parents. Low socioeconomic status older adults have larger families with more younger kin. Our results shed new light on potential mismatches between the contemporary family networks of older adults and longstanding social norms and assumptions about caregiving, family, and health policies.

Effect of weak intermolecular interactions on the ionization of benzene derivatives dimers.

The interactions between π-systems in dimers of aromatic molecules lead to particularly stable conformations within the relative orientations of the monomers. Extensive research has been conducted on the properties of these complexes in the neutral state. However, in recent decades, there has been a significant surge in applications harnessing these structures for electrical purposes. Therefore, this study places particular emphasis on a deeper understanding of the redox properties of these compounds and how to modify them. To achieve this, we have focused on modeling the effect of a wide range of functional groups on the redox properties of benzene derivatives, observing a correlation between these properties and the change in the molecular dipole moment. Then, we investigated the effect of π-stacking interactions on these properties in dimers formed by either identical or different monomers. In both cases, there is an enhancement of the reducing character of the systems due to these interactions. Upon oxidation, the charge is distributed proportionally to the redox potential of each monomer. Therefore, if there is heterogeneity in these potentials, the properties of the complete cationic system will be influenced by the monomer with a greater tendency to undergo oxidation. The considered models serve as an excellent example for studying the behavior of nucleobases in DNA or aromatic amino acids, among others.

Effect of locally excited state on fluorescence transition dipole moment in quadrupolar molecules subjected to symmetry breaking charge transfer.

In excited centrosymmetric donor-acceptor triads of type A-D-A or D-A-D, symmetry breaking charge transfer (SBCT) in polar media has been explored for a few decades. SBCT is accompanied by significant reorganization of the electronic structure of the molecule, which leads to a change in the fluorescence transition dipole moment (TDM). Previously, experiments revealed a 20%-30% reduction in TDM, which occurs on the timescale of SBCT. Simple SBCT models explain this reduction. Here, the effect of the interaction of a locally excited state with zwitterionic states on TDM is investigated. This interaction is shown to have a drastic impact on the TDM and its dependence on the solvent polarity. The magnitude of TDM can decrease monotonically, increase monotonically, and also pass through a maximum with an increase in the SBCT degree due to the locally excited state effect. The scale of changes in TDM in the course of SBCT increases greatly. The conditions for the implementation of a particular scenario have been determined. This work clearly demonstrates the observable influence of upper excited states on the photochemistry and photophysics of molecules. Methods for controlling the fluorescent characteristics of quadrupolar molecules are proposed.

DFT study of electronic and nonlinear optical properties of alkaline earth metals and superalkalis doped all-cis-1, 2, 3, 4, 5, 6-hexafluorocyclohexane as an efficient excess electron system

Continual advancements are being pursued to discover innovative strategies for developing materials with remarkable nonlinear optical (NLO) response. Herein, electronic, geometric, thermodynamic and NLO properties of excess electron systems based on stacked Janus dimer, all-cis-1,2,3,4,5,6-hexafluorocyclohexane (C6H6F6)2 are thoroughly investigated. The excess electron systems are designed by doping alkaline earth metals (AEMs) on fluorine face and superalkalis on hydrogen face of Janus dimer. The higher values of vertical ionization energies (VIE) and interaction energies (Eint), confirm the electronic and thermodynamic stabilities of the designed complexes, respectively. Natural bond orbital (NBO) analysis is performed, and the excess electron character of the complexes is confirmed through frontier molecular orbital (FMO) analysis by highest occupied molecular orbital (HOMO) iso-densities. FMO shows a significant decrease in energy gaps (Egap) of the complexes (i.e., Eg = 1.80–3.12 eV), compared to the stacked Janus dimer (i.e., Eg = 9.41 eV). The transparency of the complexes to UV region is confirmed through UV–vis analyses, revealing their maximum absorption in visible and near-IR regions. The higher NLO response of the designed excess electron systems is further proved by the greater values of first hyperpolarizability (β o ) i.e., up to 1.70 × 106 au. Moreover, the time dependent-density functional theory (TD-DFT) computations and two-level model are employed to investigate the controlling factors of hyperpolarizability, illustrating the contribution of transition energy (∆E3), change in dipole moment (∆μ) and oscillator strength (f o ) in controlling the β o . Ab-initio molecular dynamics (AIMD) simulation further confirm that the designed superalkalide complexes are kinetically and thermally stable. The thorough investigation of these excess electron systems proves them an appropriate candidate for NLO applications.

Taking Liberty with Imagination and Gender in Northanger Abbey

In Northanger Abbey Austen presents the evolution and devolution of a romantic relationship that reveals what is lost when shame brings two non-heteronormative partners into a conventional social contract: the witty conversations and imaginative flights of fancy that Catherine Morland and Henry Tilney sustain in their courtship fade and finally disappear as they take their places in the symbolic order. Both experience a turning point in their development when Henry realizes and seemingly rebukes Catherine for suspecting that his father was responsible for his mother’s death. That critical moment changes everything for them, as they surrender their fluidity and pursue a more generic path to marriage that Austen’s metaleptic narrator cagily challenges as the novel concludes.

Biomechanics of the Human Knee Joint in Maximum Voluntary Isometric Flexion: Study of Changes in Applied Moment, Agonist-Antagonist Participations, Joint Center, and Flexion Angle.

Estimation of the knee joint strength by maximum voluntary isometric contraction (MVIC) is a common practice to assess strength, coordination, safety to return to work or engage in sports after an injury, and to evaluate the efficacy of treatment modalities and rehabilitation strategies. In this study, we utilize a previously validated coupled finite element-musculoskeletal model of the lower extremity to explore the sensitivity of output measures (posterior cruciate ligament [PCL]/muscle/contact forces and passive moments) in knee MVIC flexion exercises at seated position. To do so, at three knee flexion angles (KFA), input measures (resistance moment and contribution moments of quadriceps and gastrocnemii) were varied at four levels each using the Taguchi design of experiment. Our findings reveal significant increases in PCL forces with KFA (p < 0.01), net MVIC moment (p < 0.01), and resistance moment of quadriceps (p < 0.01). In contrast, they drop at larger activity in gastrocnemii (p < 0.01). Tibiofemoral (TF) contact forces increase with the net MVIC moment (p < 0.01). The passive knee flexion moment, while highly dependent on the location at which computed, also increases with the net MVIC moment (p < 0.01). Changes in KFA, MVIC moment, and proportions thereof carried by quadriceps and/or gastrocnemii substantially affect biomechanics of the joint. Compared with level walking and stair ascent, slightly larger contact forces/stresses and much greater PCL forces are computed. This study improves our understanding of the knee joint behavior during MVIC in effective evaluation and rehabilitation interventions. Besides, it emphasizes the importance of positioning the joint center in model studies.

Stick, slip... bounce? Influence of violin bow rotational inertia on bouncing strokes

Prior perceptual tests using an experimental bow whose moment of inertia (relative to the pivot around the thumb) could be modified by moving small masses along the stick have indicated that violinists exhibit significant sensitivity to this parameter. This sensitivity was particularly notable when playing bouncing strokes like sautillé: some players reported perceiving a shift in the bouncing point, which refers to where the bow naturally bounces. Using the same experimental bow, we wanted to investigate further this influence of the bow rotational inertia. Through modal analysis, we examined the influence of moment of inertia on the bow's dynamic behavior. Additionally, a playing experiment involving motion capture was conducted on one player to explore how his control parameters were affected by a change of moment of inertia. This is of interest for bow makers as they can easily adjust the moment of inertia without affecting the stick's integrity by just varying the weight of the tip plate.

Maupertuis and the Reshaping of Natural History in Eighteenth-Century France

Abstract In this paper, I analyze a momentous change in eighteenth century French life sciences. Whereas in the first half of the century the conception of natural history as the systematic collection of facts had been most successful, at mid-century a new approach emerged. This approach was characterized by an accent on general philosophical themes rather than on observation and experiment. I study the grounds and features of this historical shift through the work of Maupertuis, who published papers in institutional (or Baconian) natural history in his early years, but then adopted a more speculative approach to the life sciences.

Solvatochromism, preferential solvation and excited state dipole moments of flufenamic acid in different solvent polarities

The influence of pure solvent and binary solvent mixtures on the optical properties of non-steroidal anti-inflammatory drug (NSAID) molecule, specifically flufenamic acid (FLA), has been studied using absorption and fluorescence spectroscopic techniques. A bathochromic shift is observed in the emission wavelength of FLA with an increase in the solvent polarity of pure solvents, attributed to the highest stability of the excited state. The spectral properties are correlated with Lippert–Mataga, solvent polarity parameter, Kamlet, and Catalan solvent polarity parameters, suggesting that both general and specific solvent effects influence the spectral properties, with general solvent effects dominating over specific solvent effects. Preferential solvation studies have been carried out in tetrahydrofuran (THF) and water solvent mixture, revealing variations in the preference for solvation of FLA as a function of the mole fraction of water. Solvatochromic data are utilized to estimate the excited state dipole moment in pure solvents using different solvatochromic methods, revealing that the excited state dipole moment of FLA is higher than its ground state counterpart. The increase in dipole moment in the excited state compared to the ground state is explained based on intramolecular charge transfer (ICT), with elaboration and discussion on the possible resonance structure corresponding to ICT, inferring the more polar nature of the excited state compared to the ground state. The effect of solute polarizability on the excited state dipole moment and change in dipole moment is also discussed.

Confounder-adjusted covariances of system outputs and applications to structural health monitoring

Automated damage detection is an integral component of each structural health monitoring (SHM) system. Typically, measurements from various sensors are collected and reduced to damage-sensitive features, and diagnostic values are generated by statistically evaluating the features. Since changes in data do not only result from damage, it is necessary to determine the confounding factors (environmental or operational variables) and to remove their effects from the measurements or features. Many existing methods for correcting confounding effects are based on different types of mean regression. This neglects potential changes in higher-order statistical moments, but in particular, the output covariances are essential for generating reliable diagnostics for damage detection. This article presents an approach to explicitly quantify the changes in the covariance, using conditional covariance matrices based on a non-parametric, kernel-based estimator. The method is applied to the Munich Test Bridge and the KW51 Railway Bridge in Leuven, covering both raw sensor measurements (acceleration, strain, inclination) and extracted damage-sensitive features (natural frequencies). The results show that covariances between different vibration or inclination sensors can significantly change due to temperature changes, and the same is true for natural frequencies. To highlight the advantages, it is explained how conditional covariances can be combined with standard approaches for damage detection, such as the Mahalanobis distance and principal component analysis. As a result, more reliable diagnostic values can be generated with fewer false alarms.

Optimizing the Landing Stability of Blended-Wing-Body Aircraft with Distributed Electric Boundary-Layer Ingestion Propulsors through a Novel Thrust Control Configuration

The imperative for energy conservation and environmental protection has led to the development of innovative aircraft designs. This study explored a novel thrust control configuration for blended-wing-body (BWB) aircraft with distributed electric boundary-layer ingestion (BLI) propulsors, addressing the issues of sagging and altitude loss during landing. The research focused on a small-scale BWB demonstrator equipped with six BLI fans, each with a 90 mm diameter. Various thrust control configurations were evaluated to achieve significant thrust reduction while maintaining lift, including dual-layer sleeve, separate flap-type, single-stage linkage flap-type, and dual-stage linkage flap-type configurations. The separate flap-type configuration was tested through ground experiments. Control experiments were conducted under three different experimental conditions as follows: deflection of the upper cascades only, deflection of the lower cascades only, and symmetrical deflection of both cascades. For each condition, the deflection angles tested were 0°, 10°, 20°, 30°, 40°, 50°, and 60°. The thrust reductions observed for these three conditions were 0%, 37.5%, and 27.5% of the maximum thrust, respectively, without additional changes in the pitch moment. A combined thrust adjustment method maintaining a zero pitch moment demonstrated a linear thrust reduction to 20% of its initial value. The experiment concluded that the novel thrust control configuration effectively adjusted thrust without altering the BLI fans’ rotation speed, solving the coupled lift–thrust problem and enhancing BWB landing stability.

Controlling Ultrafast Magnetization Dynamics via Coherent Phonon Excitation in a Ferromagnet Monolayer.

Exploring ultrafast magnetization control in 2D magnets via laser pulses is established, yet the interplay between spin dynamics and the lattice remains underexplored. Utilizing real-time time-dependent density functional theory (rt-TDDFT) coupled with Ehrenfest dynamics and nonadiabatic molecular dynamics (NAMD) simulations, we systematically investigate the laser-induced spin-nuclei dynamics with pre-excited A1g and E2g coherent phonons in the 2D ferromagnet Fe3GeTe2 (FGT) monolayer. Selective pre-excitation of coherent phonons under ultrafast laser irradiation significantly alters the local spin moment of FGT, consequently inducing additional spin loss attributed to the nuclear motion-induced asymmetric interatomic charge transfer. Excited spin-resolved charge undergoes a bidirectional spin-flip between spin-down and spin-up states, characterized by a subtle change in the spin moment within approximately 100 fs, followed by unidirectional spin-flip, which will further contribute to the spin moment loss of FGT within tens of picoseconds. Our results shed light on the coupling of coherent phonons with magnetization dynamics in 2D limit.

Research on the change of the combined moment of inertia for two-link manipulator with angular coordinate system

The main of the problems of the development of two-link manipulators with an angular coordinate system is the lack of effective and universal control systems capable of implementing energy-intensive modes of movement. This is due to the design features of the pointer system of such manipulators and the methods of their use. During the operation of the manipulator, significant dynamic loads occur in its drive system, which create oscillations of the mechanical system and reduce the accuracy of work. The control system must also effectively compensate for such dynamic variations. Dynamic equations of motion used to build manipulator control controllers, which allow taking into account various features of using manipulators. These mathematical models necessarily contain one of the characteristics in the form of the combined moment of inertia of the mechanical system, which is important in the calculation of differential equations and the determination of kinematic parameters of motion. In this article, the combined moments of inertia of the boom system of a two-link manipulator with an angular coordinate system are determined. A study was carry out and it shown that the nature of the change in the combined moments of inertia influenced by the modes of movement of the boom system links. The results of the study showed that the combined moment of inertia of the boom system of the manipulator is not a constant value, which does not change uniformly under special operating conditions of the machine. To determine the combined moments of inertia, the method of bringing the kinetic energy of the moving system to the drive mechanism was apply. This is relevant, because in the future it will be necessary to adjust the unevenness of the movement of the manipulator links by the drive itself. The study was conduct for a typical linear motion mode and a motion mode with a change in speed along a parabolic trajectory.

The efficacy of the Novel Hybrid Passive Spring Damper Ankle Foot Orthosis regard to kinetic and kinematic parameters of patients with Multiple Sclerosis: An intervention study

ABSTRACT Drop foot is a common consequence of Multiple Sclerosis (MS), which may be improved somewhat by an ankle-foot orthosis (AFO). This study aimed to examine the immediate effect of using the recently developed Novel Hybrid Passive Spring Damper AFO (the novel HPSDAFO) on the kinetic and kinematic parameters of patients with MS (PwMS) in the sagittal plane. Twelve PwMS who suffered a unilateral drop foot participated in this study and fitted with the novel HPSDAFO. They walked with the novel HPSDAFO on the affected side and shoe on the affected side at a self-selected speed. Walking by the novel HPSDAFO, the symmetry of all of the evaluated sagittal kinetic and kinematic parameters improved noticeably. The range of ankle plantarflexion and knee flexion increased significantly at the stance phase. Power generation increased at all three joints. The peak of ankle dorsiflexion at early stances and the first peak of knee extension moments increased significantly but decreased at the hip joint. Changes in sagittal ROM, moment, and power generation in the plane and the improved symmetry revealed a more normal walking by using the novel HPSDAFO on the affected limb of PwMS.

Tuning Two-Photon Absorption in Rhodopsin Chromophore via Backbone Modification: The Story Told by CC2 and TD-DFT.

We investigate here a systematic way to tune two-photon transition strengths (δ2PA) and two-photon absorption (2PA) cross sections (σ2PA) of the rhodopsin's chromophore 11-cis-retinal protonated Schiff base (RPSB) via the modulation of the methyl groups pattern along its polyene chain. Our team employed the resolution of identity, coupled cluster approximate second order (RI-CC2) method with Dunning's aug-cc-pVDZ basis set, to determine the structural impact on δ2PA, as well as its correlation to both transition dipole moments and permanent electric dipole moments. Seven structures were probed in vacuo, including five-double-bond-conjugated model of the native chromophore, shortened by the β-ionone ring (RPSB5), and its de/methylated analogues: 9-methyl, 13-methyl, planar and twisted models of 9,10-dimethyl and 9,10,13-trimethyl. Our results demonstrate that the magnitude of δ2PA is dictated by both the position and number of methylated groups attached to its polyene chain as well as the degree of dihedral twist that is introduced due to the de/methylation. In fact, a strong correlation between δ2PA enhancement and the presence of a C13-methyl group in the planar RPSB5 species is found. Trends in δ2PA values follow the trends observed in their corresponding changes in the permanent dipole moment upon the S0-S1 excitation nearly exactly. The assessment of four DFT functionals, i.e., M11, MN15, CAM-B3LYP, and BHandHLYP, previously found most successful in predicting 2PA properties in biological chromophores, points to a long-range-corrected hybrid meta-GGA M11 as the top-performing functional, albeit still delivering underestimated δ2PA and σ2PA values by a factor of 3.3-5.3 with respect to the CC2 results. In the case of global-hybrid meta-NGA (MN15), as well as CAM-B3LYP and BHandHLYP functionals, this factor deteriorates significantly to 6.7-20.9 and is mostly related to significantly lower quality of the ground- and excited-state dipole moments.

Effects of transition metals (V, Cr, Mn, Fe and Ni) doping on magnetic properties of Co-based amorphous alloys

Amorphous alloys exhibit numerous interesting and abundant magnetic properties due to their disordered structural traits and have been extensively studied by researchers. In this work, the effects of a small amount of transition metals doping on the magnetic properties of Co80-xMxB20 (x = 0, 2, 4, 6, 8, 10; M = V, Cr, Mn, Fe, Ni) amorphous alloys were systematically investigated by utilizing first-principles molecular dynamics. The trend of the magnetic moment change in the simulated calculation conforms well to the experimental results. The doping of V atoms leads to the fastest rate of decrease in the magnetic moment of the surrounding Co atoms, and there is only an antiferromagnetic interaction between the V and Co atoms. When doped with Cr and Mn atoms, there is mutual competition between ferromagnetic and antiferromagnetic coupling in the amorphous alloy, Cr reduces the magnetic moment of the surrounding Co atoms, while the change in the magnetic moment of the Co atoms around Mn is small. The doping of Fe and Ni causes an increase in the magnetic moment of the surrounding Co atoms. The reason may be due to the charge transfer between atoms. The doping of Fe and Ni has a small effect on the average magnetic moment of the Co atoms in the amorphous alloy. The results provide necessary theoretical support for the development of the Co-based amorphous alloys with excellent magnetic characteristics.

Enhancing Photoswitchable Wetting Properties of Hydrophobic Porous Spiropyran Copolymer Surfaces Through Surface Roughness Engineering

AbstractSurfaces with photoswitchable wettability are of great interest for various applications such as smart coatings or liquid condensation. The photochromic ring opening reaction of spiropyran (SP) to merocyanine (MC) implies a high dipole moment change, making it interesting for photo‐controlled wetting properties. In addition to the material chemistry, surface wettability is influenced by the surface topography. Porous SP copolymers with various micro‐/nanostructures, that is, different submicron roughness, are fabricated via polymerization‐induced phase separation. The influence of the surface topography on the photoswitchable wetting properties is studied. Surfaces with arithmetic mean roughness (Sa) below 150 nm exhibited a maximum static contact angle (SCA) photoswitch up to 16° from 124 ± 6° to 108 ± 4° upon UV exposure. While superhydrophobic surfaces with higher Sa (157 – 608 nm) showed an insignificant SCA switch. The latter surfaces have a SCA above 150° and low CA hysteresis indicating small and insufficient contact with SP/MC surface asperities for the switch. With the optimized surfaces, photo‐controlled water condensation is studied on microscale and showed that the condensate droplets merged faster, and formed larger droplets pinned to the original contact lines on surfaces switched to the less hydrophobic state.

Photoinduced Magnetization Switching in Organic Molecules Achieved Through Stabilization of the Triplet Excited States

AbstractOrganic photoresponsive materials, which change their physical properties upon irradiation with light, are attracting tremendous scientific attention, as they offer a flexible and sustainable platform for developing various optoelectronic devices. In this work, photoinduced magnetization switching in two carbazole‐functionalized organic molecules, (9H‐carbazol‐9‐yl)(4‐chlorophenyl)methanone (ClPhCz) and (9H‐carbazol‐9‐yl)(2,4‐dichlorophenyl)methanone (DClPhCz) is reported for the first time. It was found that stabilization of the triplet excited state in those molecules is long enough for a net change in magnetic moment to be detected with a SQUID magnetometer. The change in magnetic moment upon excitation with a blue light laser was larger in ClPhCz, remaining high upon repeating the photoirradiation. In contrast, DClPhCz exhibited a smaller magnetic response, which gradually decreased upon repeating the experiment.

Quantifying Hydrogen-Bonding Interactions in the Self-Assembly of Photoresponsive Azobenzene Amphiphiles at the Air-Water Interface.

Amphiphilic azobenzene molecules offer ample scope to design functional supramolecular systems in an aqueous medium that can be controlled by light. Despite their widespread applications in photopharmacology and optoelectronics, the self-assembly pathways and energy landscapes of these systems are not well understood. Here, we report combined molecular dynamics (MD) simulation and surface manometry studies on a specially designed alkylated, meta-substituted azobenzene derivative to quantify the hydrogen-bonding interactions in the self-assembled monolayers of its photoisomers. The z-density profile, radial distribution function, order parameters, and hydrogen bond analyzed using MD simulations corroborated the experimental observations of changes in surface pressure, dipole moment, and thickness of the monolayers. Even a small change in the number of hydrogen bonds in the molecule-molecule and molecule-water interactions causes significant changes in the monolayer properties. These results are fundamentally important for engineering photoresponsive molecules with tailored properties for applications in targeted drug delivery and other industrial applications.

Variability in musculoskeletal fatigue responses associated with repeated exposure to an occupational overhead drilling task completed on successive days

Emerging research suggests that muscular and kinematic responses to overhead work display a high degree of variability in fatigue-related muscular and kinematics changes, both between and within individuals when evaluated across separate days. This study examined whether electromyographic (EMG), kinematic, and kinetic responses to an overhead drilling task performed until volitional fatigue were comparable to those of a repeated identical exposure of the task completed 1 week later. Surface EMG and intramuscular EMG, sampled from 7 shoulder muscles, and right upper limb kinematics and kinetics were analyzed from 15 male and 14 female participants. No significant day-to-day changes in EMG mean power frequency (MPF) were observed, though serratus anterior displayed significantly less fatigue-related increase in EMG root-mean-squared (RMS) signal amplitude on day 2. Unfatigued upper kinematics on day 2 featured an increase in thoracohumeral elevation, elbow flexion, and decrease in wrist ulnar deviation compared to unfatigued state on day 1. Fatigue-related changes in shoulder joint flexion moment that were present on day 1 were reduced on day 2, suggesting that a more efficient overhead work strategy was learned and preserved across successive days. Day-to-day changes in upper limb joint angle variability, quantified by median absolute deviation (MdAD), were joint dependent. Despite yielding a variable fatigue-related kinetic strategy on both days, kinematic and kinetic fatigue-related changes on a second day of completing an overhead drilling task suggested a potential kinematic learning effect.