Average distance in a hierarchical scale-free network: an exact solution

Various real systems simultaneously exhibit scale-free and hierarchical structure. In this paper, we study analytically average distance in a deterministic scale-free network with hierarchical organization. Using a recursive method based on the network construction, we determine explicitly the average distance, obtaining an exact expression for it, which is confirmed by extensive numerical calculations. The obtained rigorous solution shows that the average distance grows logarithmically with the network order (number of nodes in the network). We exhibit the similarity and dissimilarity in average distance between the network under consideration and some previously studied networks, including random networks and other deterministic networks. On the basis of the comparison, we argue that the logarithmic scaling of average distance with network order could be a generic feature of deterministic scale-free networks.Comment: Definitive version published in Journal of Statistical Mechanic

Anomalous behavior of trapping on a fractal scale-free network

It is known that the heterogeneity of scale-free networks helps enhancing the efficiency of trapping processes performed on them. In this paper, we show that transport efficiency is much lower in a fractal scale-free network than in non-fractal networks. To this end, we examine a simple random walk with a fixed trap at a given position on a fractal scale-free network. We calculate analytically the mean first-passage time (MFPT) as a measure of the efficiency for the trapping process, and obtain a closed-form expression for MFPT, which agrees with direct numerical calculations. We find that, in the limit of a large network order $V$, the MFPT $$ behaves superlinearly as $\sim V^{{3/2}}$ with an exponent 3/2 much larger than 1, which is in sharp contrast to the scaling $\sim V^{\theta}$ with $\theta \leq 1$, previously obtained for non-fractal scale-free networks. Our results indicate that the degree distribution of scale-free networks is not sufficient to characterize trapping processes taking place on them. Since various real-world networks are simultaneously scale-free and fractal, our results may shed light on the understanding of trapping processes running on real-life systems.Comment: 6 pages, 5 figures; Definitive version accepted for publication in EPL (Europhysics Letters

Trapping in scale-free networks with hierarchical organization of modularity

A wide variety of real-life networks share two remarkable generic topological properties: scale-free behavior and modular organization, and it is natural and important to study how these two features affect the dynamical processes taking place on such networks. In this paper, we investigate a simple stochastic process--trapping problem, a random walk with a perfect trap fixed at a given location, performed on a family of hierarchical networks that exhibit simultaneously striking scale-free and modular structure. We focus on a particular case with the immobile trap positioned at the hub node having the largest degree. Using a method based on generating functions, we determine explicitly the mean first-passage time (MFPT) for the trapping problem, which is the mean of the node-to-trap first-passage time over the entire network. The exact expression for the MFPT is calculated through the recurrence relations derived from the special construction of the hierarchical networks. The obtained rigorous formula corroborated by extensive direct numerical calculations exhibits that the MFPT grows algebraically with the network order. Concretely, the MFPT increases as a power-law function of the number of nodes with the exponent much less than 1. We demonstrate that the hierarchical networks under consideration have more efficient structure for transport by diffusion in contrast with other analytically soluble media including some previously studied scale-free networks. We argue that the scale-free and modular topologies are responsible for the high efficiency of the trapping process on the hierarchical networks.Comment: Definitive version accepted for publication in Physical Review

Combination therapy with oral treprostinil for pulmonary arterial hypertension. A double-blind placebo-controlled clinical trial

Rationale: Oral treprostinil improves exercise capacity in patients with pulmonary arterial hypertension (PAH), but the effect on clinical outcomes was unknown. Objectives: To evaluate the effect of oral treprostinil compared with placebo on time to first adjudicated clinical worsening event in participants with PAH who recently began approved oral monotherapy. Methods: In this event-driven, double-blind study, we randomly allocated 690 participants (1:1 ratio) with PAH to receive placebo or oral treprostinil extended-release tablets three times daily. Eligible participants were using approved oral monotherapy for over 30 days before randomization and had a 6-minute-walk distance 150 m or greater. The primary endpoint was the time to first adjudicated clinical worsening event: death; hospitalization due to worsening PAH; initiation of inhaled or parenteral prostacyclin therapy; disease progression; or unsatisfactory long-term clinical response. Measurements and Main Results: Clinical worsening occurred in 26% of the oral treprostinil group compared with 36% of placebo participants (hazard ratio, 0.74; 95% confidence interval, 0.56–0.97; P = 0.028). Key measures of disease status, including functional class, Borg dyspnea score, and N-terminal pro–brain natriuretic peptide, all favored oral treprostinil treatment at Week 24 and beyond. A noninvasive risk stratification analysis demonstrated that oral treprostinil–assigned participants had a substantially higher mortality risk at baseline but achieved a lower risk profile from Study Weeks 12–60. The most common adverse events in the oral treprostinil group were headache, diarrhea, flushing, nausea, and vomiting. Conclusions: In participants with PAH, addition of oral treprostinil to approved oral monotherapy reduced the risk of clinical worsening. Clinical trial registered with www.clinicaltrials.gov (NCT01560624)

Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

Goodness of fit in the Chinese context of socialization in the first three years

Based on the goodness-of-fit theory, the current research examined how parental socialization expectations and socialization practices in infancy predicted child social adjustment in the preschool year dependent on child characteristics in toddlerhood with a longitudinal sample of Chinese families. Participants were 272 Chinese mother–child dyads. Maternal socialization goals of child autonomy and obedience were assessed when the child was 6 months old. Maternal respect for autonomy and negative control were observed in free-plays at 15 months. Mothers reported child compliance and inhibitory control at 25 months and rated child externalizing behaviors at 37 months. Results showed that for children with low levels of compliance or high levels of inhibitory control, obedience socialization goals predicted more externalizing behaviors, whereas for children with high levels of compliance or low levels of inhibitory control, obedience socialization goals predicted fewer externalizing behaviors. Moreover, for children with high levels of inhibitory control, higher levels of respect for autonomy or lower levels of negative control foretold fewer externalizing behaviors. Conversely, for children with low levels of inhibitory control, lower levels of respect for autonomy or higher levels of negative control forecasted fewer externalizing behaviors. Together, our findings demonstrate that socialization expectations, socialization practices, and child characteristics are jointly predictive of social adjustment across early childhood and all the significant interactions are characterized by the pattern of a contrastive effect, therefore congruently supporting the goodness-of-fit hypotheses. (PsycInfo Database Record (c) 2022 APA, all rights reserved

Goodness of fit in the Chinese context of socialization in the first three years

Based on the goodness-of-fit theory, the current research examined how parental socialization expectations and socialization practices in infancy predicted child social adjustment in the preschool year dependent on child characteristics in toddlerhood with a longitudinal sample of Chinese families. Participants were 272 Chinese mother–child dyads. Maternal socialization goals of child autonomy and obedience were assessed when the child was 6 months old. Maternal respect for autonomy and negative control were observed in free-plays at 15 months. Mothers reported child compliance and inhibitory control at 25 months and rated child externalizing behaviors at 37 months. Results showed that for children with low levels of compliance or high levels of inhibitory control, obedience socialization goals predicted more externalizing behaviors, whereas for children with high levels of compliance or low levels of inhibitory control, obedience socialization goals predicted fewer externalizing behaviors. Moreover, for children with high levels of inhibitory control, higher levels of respect for autonomy or lower levels of negative control foretold fewer externalizing behaviors. Conversely, for children with low levels of inhibitory control, lower levels of respect for autonomy or higher levels of negative control forecasted fewer externalizing behaviors. Together, our findings demonstrate that socialization expectations, socialization practices, and child characteristics are jointly predictive of social adjustment across early childhood and all the significant interactions are characterized by the pattern of a contrastive effect, therefore congruently supporting the goodness-of-fit hypotheses. (PsycInfo Database Record (c) 2022 APA, all rights reserved