Natural Scale Research Articles

On the Relation of One-Dimensional Diffusions on Natural Scale and Their Speed Measures

It is well known that the law of a one-dimensional diffusion on natural scale is fully characterized by its speed measure. Stone proved a continuous dependence of such diffusions on their speed measures. In this paper we establish the converse direction, i.e., we prove a continuous dependence of the speed measures on their diffusions. Furthermore, we take a topological point of view on the relation. More precisely, for suitable topologies, we establish a homeomorphic relation between the set of regular diffusions on natural scale without absorbing boundaries and the set of locally finite speed measures.

The influence of Self-Guided and Guided Forest Therapy Program on Students’ Psychological Benefits

Background and objective: University students' mental health is threatened by various stressors. Forest therapy is considered an effective way to improve mental health. Many researchers have investigated the effectiveness of forest therapy programs operated by guides. Recently, although the concept of a self-guided forest therapy program has emerged without a guide, research is insufficient. Therefore, the present study aimed to explore the influence of self-guided and guided forest therapy program on students' psychological benefits.Methods: We employed a randomized 3 × 3 crossover study. Twenty-three university students were randomly assigned into three groups to eliminate the order effect. Twenty-three university students were randomly exposed to three conditions: a self-guided forest therapy program, a guided forest-therapy program, and routine activities. All participants participated in all interventions once a week for three weeks, and each intervention was conducted over a one-week washout period to eliminate the carryover effect of the intervention. Measures included the Positive and Negative Affect Schedule (PANAS), the Rosenberg Self-esteem Scale (RSES), and the Connectedness to Nature Scale (CNS).Results: As a result, self-guided and guided forest-therapy programs significantly improved participants' negative emotions and natural connectedness compared to routine activities. As for self-esteem, only a guided forest therapy program was higher than daily routine activities.Conclusion: This study shows that not only guided forest therapy programs but also self-guided forest therapy programs have a positive effect on psychological health. Therefore, these findings suggest that running guided forest therapy programs and self-guided forest therapy programs as university in-campus programs will significantly help university students' mental health.

Developing and validating the Sexual Health Literacy Scale in an Iranian adult sample

The literature has shown that sexual health literacy has limited applicability in many developing countries. The present study, therefore, aimed to develop and examine the validity and reliability of the Sexual Health Literacy Scale (SHLS) among a sample of 595 Iranian university students. The first analysis yielded themes obtained from a qualitative content analysis of the 118-item SHLS scale. Concepts were extracted using the method of latent content analysis (Bengtsson, NursingPlus Open 2:8–16, 2016). 327 initial codes were extracted and main categories (Elo and Kyngäs, J Adv Nurs. 62 (1): 107–115, 2007) or themes (Graneheim and Lundman, Nurse Education Today 24: 105–112, 2004) obtained consisting of the information source, individual barriers, understanding and application, capacity and motivation, damage, skills, sexual rights, and socio-cultural barriers. In the second analysis, the 595 students were randomly split into two groups. An exploratory factor analysis was conducted on the themes derived and quantified in Phase 1. 6 Factors were obtained and found to be consistent in both groups. Criterion-related validity of sexual health literacy was determined by stepwise multiple regression to predict marital satisfaction. The reliability of SHLS was also investigated. The third analysis examined the fit of the 6 factors obtained from the 595 students in the original sample to a new sample of 221 university students using cross-validation via confirmatory factor analysis. We developed and validated a six-factor structure of the Sexual Health Literacy Scale 106 (SHLS-106): factor 1, Sexual Skills; factor 2, Individual Socio-cultural Barriers; factor 3, Sexual Vulnerability; factor 4, Resources to Access Sexual Information; factor 5, Understanding and Application; factor 6, Capacity and Motivation. SHLS-106 shows good test–retest reliability and criterion, incremental and convergent validities. This is the first study to examine the validity and reliability of the Sexual Health Literacy Scale in an Iranian sample. Considering the acceptable validity and reliability of this instrument, the psychometric properties of SHLS-106 need to be further investigated in diverse, more extended samples to clarify the extent of application of this scale in different settings. SHLS-106 can effectively examine sexual health literacy, a dynamic scale in nature influenced by the individual, healthcare system, contextual, and social factors in different cultures.

Quantum Brownian motion induced by an inhomogeneous tridimensional space and a S1× R3 topological space-time

In this paper we investigate the Quantum Brownian motion of a point particle induced by quantum vacuum fluctuations of a massless scalar field in (3 + 1)-dimensional Minkowski spacetime with distinct conditions (Dirichlet, Neumann, mixed and quasiperiodic). The modes of the field are confined and compactified to a finite length region, which consequently provides a natural measure scale for the system. Useful expressions for the Wightman function have been obtained, which allow us to calculate analytical expressions for the velocity dispersion in all condition cases considered. We also obtain expressions for the velocity dispersion in the short and late time regimes. Finally, we exhibit some graphs in order to show the behavior of the velocity dispersions, discussing important divergencies that are present in our results.

Resumming quark's longitudinal momentum logarithms in LaMET expansion of lattice PDFs

In the large-momentum expansion for parton distribution functions (PDFs), the natural physics scale is the longitudinal momentum (pz) of the quarks (or gluons) in a large-momentum hadron. We show how to expose this scale dependence through resumming logarithms of the type lnn⁡pz/μ in the matching coefficient, where μ is a fixed renormalization scale. The result enhances the accuracy of the expansion at moderate pz>1 GeV, and at the same time, clearly shows that the partons cannot be approximated from quarks with pz∼ΛQCD which are not predominantly collinear with the parent hadron momentum, consistent with power counting of the large-momentum effective theory. The same physics mechanism constrains the coordinate space expansion at large distances z, the conjugate of pz, as illustrated in the example of fitting the moments of the PDFs.

Performance Evaluation of Natural Convection Small Scale Greenhouse Solar Dryer for Drying Grapes

Performance Evaluation of Natural Convection Small Scale Greenhouse Solar Dryer for Drying Grapes

Liver biomarkers, lipid metabolites, and risk of gestational diabetes mellitus in a prospective study among Chinese pregnant women

BackgroundLiver plays an important role in maintaining glucose homeostasis. We aimed to examine the associations of liver enzymes and hepatic steatosis index (HSI, a reliable biomarker for non-alcoholic fatty liver disease) in early pregnancy with subsequent GDM risk, as well as the potential mediation effects of lipid metabolites on the association between HSI and GDM.MethodsIn a birth cohort, liver enzymes were measured in early pregnancy (6-15 gestational weeks, mean 10) among 6,860 Chinese women. Multivariable logistic regression was performed to examine the association between liver biomarkers and risk of GDM. Pearson partial correlation and least absolute shrinkage and selection operator (LASSO) regression were conducted to identify lipid metabolites that were significantly associated with HSI in a subset of 948 women. Mediation analyses were performed to estimate the mediating roles of lipid metabolites on the association of HSI with GDM.ResultsLiver enzymes and HSI were associated with higher risks of GDM after adjustment for potential confounders, with ORs ranging from 1.42 to 2.24 for extreme-quartile comparisons (false discovery rate-adjusted P-trend ≤0.005). On the natural log scale, each SD increment of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, and HSI was associated with a 1.15-fold (95% CI: 1.05, 1.26), 1.10-fold (1.01, 1.20), 1.21-fold (1.10, 1.32), 1.15-fold (1.04, 1.27), and 1.33-fold (1.18, 1.51) increased risk of GDM, respectively. Pearson partial correlation and LASSO regression identified 15 specific lipid metabolites in relation to HSI. Up to 52.6% of the association between HSI and GDM risk was attributed to the indirect effect of the HSI-related lipid score composed of lipid metabolites predominantly from phospholipids (e.g., lysophosphatidylcholine and ceramides) and triacylglycerol.ConclusionsElevated liver enzymes and HSI in early pregnancy, even within a normal range, were associated with higher risks of GDM among Chinese pregnant women. The association of HSI with GDM was largely mediated by altered lipid metabolism.

Humans and Nature

The Human and Nature scale (HaN scale) was developed in the Western context to investigate the relationship between ideas about nature and landscape planning. This pilot study expands the HaN scale and includes religion as an independent variable to investigate perceptions of human-nature relations in Indonesia. It examines how religious affiliation and religious practices influence visions of human-nature relations. This study shows that religious affiliation makes no difference. Muslims, Catholics, Protestants, and Hindus share their acceptance of the stewardship, partnership, and participation models while rejecting the master model. However, religious practice does make a difference. Those who practice religion to a lesser extent tend to agree more with the mastery vision than those who practice religion to a greater extent. This study suggests that religion makes a difference, not in terms of what religion respondents affiliate with, but in how religious they are.

Tuning the conductance topology in solids

The inertia of trapping and detrapping of nonequilibrium charge carriers affects the electrochemical and transport properties of both bulk and nanoscopic structures in a very peculiar way. An emerging memory response with hysteresis in the current–voltage response and its eventual multiple crossing, produced by this universally available ingredient, are signatures of this process. Here, we deliver a microscopic and analytical solution for these behaviors, understood as the modulation of the topology of the current–voltage loops. Memory emergence thus becomes a characterization tool for intrinsic features that affect the electronic transport of solids such as the nature and number of trapping sites, intrinsic symmetry constraints, and natural relaxation time scales. This method is also able to reduce the seeming complexity of frequency-dependent electrochemical impedance and cyclic voltammetry observable for a variety of systems to a combination of simple microscopic ingredients.

Cosmic voids and the kinetic analysis

We consider a principal problem, that of the possible dominating role of self-consistent gravitational interaction in the formation of cosmic structures: voids and their walls in the local Universe. It is in the context of the Hubble tension as a possible indication of the difference in the descriptions of the late (local) and early (global) Universe. The kinetic Vlasov treatment enables us to consider the evolution of gravitating structures where the fundamental role has the modified gravitational potential with a cosmological constant, leading to the prediction of a local flow with a Hubble parameter that is nonidentical to that of the global Hubble flow. The Poisson equation for a potential with an additional repulsive term, including an integral equation formulation, is analyzed, and we predict the appearance of multiply connected two-dimensional gravitating structures and voids in the local Universe. The obvious consequence of the developed mechanism is that the cosmological constant poses a natural scaling for the voids, along with the physical parameters of their local environment, which can be traced in observational surveys.

Natural Selection and Scale Invariance.

This review points out that three of the essential features of natural selection-competition for a finite resource, variation, and transmission of memory-occur in an extremely simple, thermalized molecular population, one of colliding "billiard balls" subject to an anisotropy, a directional flux of energetic molecules. The emergence of scaling behavior, scale invariance, in such systems is considered in the context of the emergence of complexity driven by Gibbs free energy, the origins of life, and known chemistries in planetary and astrophysical conditions. It is suggested that the thermodynamic formalism of statistical multifractality offers a parallel between the microscopic and macroscopic views of non-equilibrium systems and their evolution, different from, empirically determinable, and therefore complementing traditional definitions of entropy and its production in living systems. Further, the approach supports the existence of a bridge between microscopic and macroscopic scales, the missing mesoscopic scale. It is argued that natural selection consequently operates on all scales-whether or not life results will depend on both the initial and the evolving boundary conditions. That life alters the boundary conditions ensures nonlinearity and scale invariance. Evolution by natural selection will have taken place in Earth's fluid envelope; both air and water display scale invariance and are far from chemical equilibrium, a complex condition driven by the Gibbs free energy arising from the entropy difference between the incoming solar beam and the outgoing infrared radiation to the cold sink of space acting on the initial conditions within evolving boundary conditions. Symmetry breaking's role in the atmospheric state is discussed, particularly in regard to aerosol fission in the context of airborne bacteria and viruses in both current and prebiotic times. Over 4.4 billion years, the factors operating to support natural selection will have evolved along with the entire system from relative simplicity to the current complexity.

Time-resolved correlation of distributed brain activity tracks E-I balance and accounts for diverse scale-free phenomena

Much of systems neuroscience posits the functional importance of brain activity patterns that lack natural scales of sizes, durations, or frequencies. The field has developed prominent, and sometimes competing, explanations for the nature of this scale-free activity. Here, we reconcile these explanations across species and modalities. First, we link estimates of excitation-inhibition (E-I) balance with time-resolved correlation of distributed brain activity. Second, we develop an unbiased method for sampling time series constrained by this time-resolved correlation. Third, we use this method to show that estimates of E-I balance account for diverse scale-free phenomena without need to attribute additional function or importance to these phenomena. Collectively, our results simplify existing explanations of scale-free brain activity and provide stringent tests on future theories that seek to transcend these explanations.

Sensitivity analysis of kinetic theory of granular flow (KTGF) and mixture models in terms of involved elemental parameters for two-phase gas-solid flow

Probing into the multiscale essence and nonlinear interactions of gas-solid flows whether in natural or industrial scale have continuously been evoking challenges in flow physics and modeling approaches. Although there are capabilities within the test bench experiments and empirical formulas to define or predict the flow characteristics in two-phase systems, the flow pattern would be still unknown, and here is where the numerical approaches thrive. Since, the corresponding non-linear equation system developed to predict the behavior of two-phase flows is intrinsically complex and makes the numerical solutions time-consuming, in this article, the sensitivity analysis of two well-known models based on the Euler-Euler approach, namely KTGF and Mixture models, is conducted in terms of continuous/dispersed shear stress and solid pressure on the accuracy, stability, and duration of solution. In the KTGF model, granular viscosity is particularly most influential term; while in the Mixture model, the numerical solution profoundly depends on the continuous phase viscosity. Moreover, it is perceived that the existence of solid pressure as a diffusive source term is consequential for the stability in the modeling process, and in high values of dispersed volume fraction, its impact on the flow behavior is distinguishable.

A Bayesian (meta-)regression model for treatment effects on the risk difference scale.

In clinical settings, the absolute risk reduction due to treatment that can be expected in a particular patient is of key interest. However, logistic regression, the default regression model for trials with a binary outcome, produces estimates of the effect of treatment measured as a difference in log odds. We explored options to estimate treatment effects directly as a difference in risk, specifically in the network meta-analysis setting. We propose a novel Bayesian (meta-)regression model for binary outcomes on the additive risk scale. The model allows treatment effects, covariate effects, interactions and variance parameters to be estimated directly on the linear scale of clinical interest. We compared effect estimates from this model to (1) a previously proposed additive risk model by Warn, Thompson and Spiegelhalter ("WTS model") and (2) backtransforming the predictions from a logistic model to the natural scale after regression. The models were compared in a network meta-analysis of 20 hepatitis C trials, as well as in the analysis of simulated single trial settings. The resulting estimates diverged, in particular for small sample sizes or true risks close to 0% or 100%. Researchers should be aware that modelling untransformed risk can yield very different results from default logistic models. The treatment effect in participants with such extreme predicted risks weighed more heavily on the overall treatment effect estimate from our proposed model compared to the WTS model. In our network meta-analysis, this sensitivity of our proposed model was needed to detect all information in the data.

Bioinspired fish-scale-like magnesium composites strengthened by contextures of continuous titanium fibers: Lessons from nature

Abstract Natural fish scales demonstrate outstanding mechanical efficiency owing to their elaborate architectures and thereby may serve as ideal prototypes for the architectural design of man-made materials. Here bioinspired magnesium composites with fish-scale-like orthogonal plywood and double-Bouligand architectures were developed by pressureless infiltration of a magnesium melt into the woven contextures of continuous titanium fibers. The composites exhibit enhanced strength and work-hardening ability compared to those estimated from a simple mixture of their constituents at ambient to elevated temperatures. In particular, the double-Bouligand architecture can effectively deflect cracking paths, alleviate strain localization, and adaptively reorient titanium fibers within the magnesium matrix during the deformation of the composite, representing a successful implementation of the property-optimizing mechanisms in fish scales. The strength of the composites, specifically the effect of their bioinspired architectures, was interpreted based on the adaptation of classical laminate theory. This study may offer a feasible approach for developing new bioinspired metal-matrix composites with improved performance and provide theoretical guidance for their architectural designs.

Dynamics of the Box-Ball System with Random Initial Conditions via Pitman’s Transformation

The box-ball system (BBS), introduced by Takahashi and Satsuma in 1990, is a cellular automaton that exhibits solitonic behaviour. In this article, we study the BBS when started from a random two-sided infinite particle configuration. For such a model, Ferrari et al. recently showed the invariance in distribution of Bernoulli product measures with density strictly less than 1 2 \frac {1}{2} , and gave a soliton decomposition for invariant measures more generally. We study the BBS dynamics using the transformation of a nearest neighbour path encoding of the particle configuration given by ‘reflection in the past maximum’, which was famously shown by Pitman to connect Brownian motion and a three-dimensional Bessel process. We use this to characterise the set of configurations for which the dynamics are well-defined and reversible (i.e. can be inverted) for all times. The techniques developed to understand the deterministic dynamics are subsequently applied to study the evolution of the BBS from a random initial configuration. Specifically, we give simple sufficient conditions for random initial conditions to be invariant in distribution under the BBS dynamics, which we check in several natural examples, and also investigate the ergodicity of the relevant transformation. Furthermore, we analyse various probabilistic properties of the BBS that are commonly studied for interacting particle systems, such as the asymptotic behavior of the integrated current of particles and of a tagged particle. Finally, for Bernoulli product measures with parameter p ↑ 1 2 p\uparrow \frac 12 (which may be considered the ‘high density’ regime), the path encoding we consider has a natural scaling limit, which motivates the introduction of a new continuous version of the BBS that we believe will be of independent interest as a dynamical system.

The response of high density turbidity currents and their deposits to an abrupt channel termination at a slope break: Implications for channel–lobe transition zones

ABSTRACTThe transition between the slope and basin floor is typically marked by a slope break, in some cases causing channels to terminate and turbidity currents to undergo a loss of confinement. It is thus essential to understand how these slope breaks and losses of confinement influence the hydrodynamic evolution of turbidity currents and impact their depositional variability within natural scale channel mouth settings. Flume experiments, utilizing Shields scaling, are conducted to study how channel slope angle (3°, 6° and 9°) and initial suspended sediment concentrations (12 to 18% by volume) impact the hydrodynamics and deposit geometries of high density turbidity currents, subject to a simultaneous break of slope and loss of confinement. Measured velocity and concentration profiles indicate that turbidity currents are supercritical, with mean velocities between 0.80 m s−1 and 1.04 m s−1 and depth‐averaged basal concentrations between 9.2% and 23.9%, yielding bed shear velocities between 0.050 m s−1 and 0.064 m s−1. Upon encountering the slope break and loss of confinement, turbidity currents exhibit increases to their densimetric Froude numbers and shear velocities. This is due primarily to two factors: firstly, turbidity currents continue to accelerate during an initial period of velocity lag as their residual momentum gradually dissipates; and, secondly, expansion via flow relaxation collapses their structure towards the bed. The corresponding depositional geometries of these processes reveal that turbidity currents produce elongate channel–lobe transition zones that disconnect channel and basin deposits. The length to width ratios of channel–lobe transition zones decrease as the initial sediment concentrations of turbidity currents increase, while a reduction in the channel slope break angle reduces their length to width ratios. Corresponding, lobe elements are observed to increase in length, width and thickness with increasing initial sediment concentrations, while a reduction in channel slope break angle reduces their dimensions due to enhanced slope deposition.

Attosecond-Angstrom free-electron-laser towards the cold beam limit

Electron beam quality is paramount for X-ray pulse production in free-electron-lasers (FELs). State-of-the-art linear accelerators (linacs) can deliver multi-GeV electron beams with sufficient quality for hard X-ray-FELs, albeit requiring km-scale setups, whereas plasma-based accelerators can produce multi-GeV electron beams on metre-scale distances, and begin to reach beam qualities sufficient for EUV FELs. Here we show, that electron beams from plasma photocathodes many orders of magnitude brighter than state-of-the-art can be generated in plasma wakefield accelerators (PWFAs), and then extracted, captured, transported and injected into undulators without significant quality loss. These ultrabright, sub-femtosecond electron beams can drive hard X-FELs near the cold beam limit to generate coherent X-ray pulses of attosecond-Angstrom class, reaching saturation after only 10 metres of undulator. This plasma-X-FEL opens pathways for advanced photon science capabilities, such as unperturbed observation of electronic motion inside atoms at their natural time and length scale, and towards higher photon energies.

Graph-based quantum response theory and shadow Born-Oppenheimer molecular dynamics.

Graph-based linear scaling electronic structure theory for quantum-mechanical molecular dynamics simulations [A. M. N. Niklasson et al., J. Chem. Phys. 144, 234101 (2016)] is adapted to the most recent shadow potential formulations of extended Lagrangian Born-Oppenheimer molecular dynamics, including fractional molecular-orbital occupation numbers [A. M. N. Niklasson, J. Chem. Phys. 152, 104103 (2020) and A. M. N. Niklasson, Eur. Phys. J. B 94, 164 (2021)], which enables stable simulations of sensitive complex chemical systems with unsteady charge solutions. The proposed formulation includes a preconditioned Krylov subspace approximation for the integration of the extended electronic degrees of freedom, which requires quantum response calculations for electronic states with fractional occupation numbers. For the response calculations, we introduce a graph-based canonical quantum perturbation theory that can be performed with the same natural parallelism and linear scaling complexity as the graph-based electronic structure calculations for the unperturbed ground state. The proposed techniques are particularly well-suited for semi-empirical electronic structure theory, and the methods are demonstrated using self-consistent charge density-functional tight-binding theory both for the acceleration of self-consistent field calculations and for quantum-mechanical molecular dynamics simulations. Graph-based techniques combined with the semi-empirical theory enable stable simulations of large, complex chemical systems, including tens-of-thousands of atoms.

A 10-Year Cardiovascular Risk in Adults with Different Levels of Spiritual Health: Tehran Lipid and Glucose Study.

Previous studies have shown that spiritual experience may reduce cardiovascular disease (CVDs). However, little is known about the relationship between spiritual health and the gender-specific risk of CVDs in communities with different cultures. A total of 3249 individuals (53.7% female, 75.0% middle-aged) participated in the Tehran Lipid and Glucose Study (TLGS) from 2015 to 2017 were included. Based on the ACC/AHA pooled cohort equation, CVD risk over ten years was examined. Spiritual health was measured using a developed tool for measuring spiritual health in Muslim populations (SHIMA-48). Linear regression models were used to assess the association between spiritual health and ACC/AHA risk scores. The natural logarithm scale was calculated to consider the normal distribution hypothesis of the regression model. The current results suggest a slight but significant increase in the mean of spiritual health in women compared to men in both cognitive/emotional and behavioral dimensions (P < 0.001). In both sexes, a higher prevalence of smoking was observed in participants with lower levels of spiritual health (P < 0.004). In men, compared to those with a low level of spiritual health (the first tertile), the logarithm of the ACC-AHA risk score was reduced by 0.11 (P = 0.004) and 0.18 (P < 0.001) for those in the second and third tertiles of spiritual health, respectively. This result may be attributed to higher cigarette smoking among the latter group. Similar results were not observed in women. Current results indicate a gender-specific association between spiritual health and cardiovascular disease risk. Our findings imply that promoting spiritual health can be considered an effective strategy in future preventive interventions, primarily by controlling the desire to smoke in men.