First-order Structure Research Articles

Cold-start link prediction integrating community information via multi-nonnegative matrix factorization

Cold-start link prediction has attracted much attention as a sub-problem of link prediction recently. However, due to the influence of some isolated nodes existing in the network, the network structure is disconnected, so that the existing methods cannot realize the task of link prediction well. Therefore, how to excavate and fuse some available information from the network data to help complete the link prediction is the key to solve this problem. In this paper, we propose a multi-nonnegative matrix factorization model that implements the prediction of missing edges of isolated nodes in the overall disconnected state of the network structure. Through several methods, three global and local attribute information, namely the community membership information of the node attributes, the attribute similarity between the nodes, and the partial first-order structure characteristics existing among the nodes, are extracted on network. Then, using the proposed new model, the cold-start link prediction problem on the structured disconnected network is finally solved by integrating the three kinds of information from multiple perspective. Extensive experiments demonstrate that our proposed method performs better than state-of-the-art methods when solving the cold-start link prediction problem.

Enumerating teams in first-order team logics

We start the study of the enumeration complexity of different satisfiability problems in first-order team logics. Since many of our problems go beyond DelP, we use a framework for hard enumeration analogous to the polynomial hierarchy, which was recently introduced by Creignou et al. (Discret. Appl. Math. 2019). We show that the problem to enumerate all satisfying teams of a fixed formula in a given first-order structure is DelNP-complete for certain formulas of dependence logic and independence logic. For inclusion logic formulas, this problem is even in DelP. Furthermore, we study the variants of this problem where only maximal or minimal solutions, with respect to cardinality or inclusion, are considered. For the most part these share the same complexity as the original problem. One exception is the cardinality minimum-variant for inclusion logic, which is DelNP-complete, the other is the inclusion maximal-variant for dependence and independence logic, which is in Del+NP and DelNP-hard.

On the p-Laplacian evolution equation in metric measure spaces

The p-Laplacian evolution equation in metric measure spaces has been studied as the gradient flow in L2 of the p-Cheeger energy (for 1<p<∞). In this paper, using the first-order differential structure on a metric measure space introduced by Gigli, we characterise the subdifferential in L2 of the p-Cheeger energy. This gives rise to a new definition of the p-Laplacian operator in metric measure spaces, which allows us to work with this operator in more detail. In this way, we introduce a new notion of solutions to the p-Laplacian evolution equation in metric measure spaces. For p=1, we obtain a Green-Gauss formula similar to the one by Anzellotti for Euclidean spaces, and use it to characterise the 1-Laplacian operator and study the total variation flow. We also study the asymptotic behaviour of the solutions of the p-Laplacian evolution equation, showing that for 1≤p<2 we have finite extinction time.

The Neumann and Dirichlet problems for the total variation flow in metric measure spaces

Abstract We study the Neumann and Dirichlet problems for the total variation flow in doubling metric measure spaces supporting a weak Poincaré inequality. We prove existence and uniqueness of weak solutions and study their asymptotic behavior. Furthermore, in the Neumann problem we provide a notion of solutions which is valid for L 1 {L^{1}} initial data, as well as prove their existence and uniqueness. Our main tools are the first-order linear differential structure due to Gigli and a version of the Gauss–Green formula.

CMOS Compatible First-Order Current Mode Universal Filter Structure and its Possible Tunable Variant

A novel first-order universal filter structure supporting current mode operation is proposed in this paper. The filter has a single active building block based realization and utilizes an extra-X second-generation current conveyor as an active building block. Additionally, the proposed circuit employs a grounded resistor and a grounded capacitor as passive components. The circuit has the ability to deliver the all-pass, high-pass, and low-pass functionalities simultaneously without meeting any passive components matching constraint. High output impedance and load insensitive outputs are other remarkable signal processing features offered by the proposed filter structure. Theoretical behavior of the proposed filter is described by presenting ideal, non-ideal, parasitic, and stability analyses. Additionally, the resistorless variant of the proposed filter is also shown to impart the tunability feature. Personal simulation program with integrated circuit emphasis (PSPICE) simulation results are presented to verify the theoretically described performance of the proposed universal filter. Complementary metal oxide semiconductor (CMOS) realization of extra-X second-generation current conveyor is utilized for the purpose of simulations, therefore, the filter is CMOS compatible.

Almost o-minimal structures and [formula omitted]-structures

We propose new structures called almost o-minimal structures and X-structures. The former is a first-order expansion of a dense linear order without endpoints such that the intersection of a definable set with a bounded open interval is a finite union of points and open intervals. The latter is a variant of van den Dries and Miller's analytic geometric categories and Shiota's X-sets and Y-sets. In them, the family of definable sets are closed only under proper projections unlike first-order structures. We demonstrate that an X-expansion of an ordered divisible abelian group always contains an o-minimal expansion of an ordered group such that all bounded X-definable sets are definable in the structure.Another contribution of this paper is a uniform local definable cell decomposition theorem for almost o-minimal expansions of ordered groups M=(M,<,0,+,…). Let {Aλ}λ∈Λ be a finite family of definable subsets of Mm+n, where m and n are positive integers. Take an arbitrary positive element R∈M and set B=]−R,R[n. Then, there exists a finite partition into definable setsMm×B=X1∪…∪Xk such that B=(X1)b∪…∪(Xk)b is a definable cell decomposition of B for any b∈Mm and either Xi∩Aλ=∅ or Xi⊆Aλ for any 1≤i≤k and λ∈Λ. Here, the notation Sb denotes the fiber of a definable subset S of Mm+n at b∈Mm. We introduce the notion of multi-cells and demonstrate that any definable set is a finite union of multi-cells in the course of the proof of the above theorem.

Steady-state and transient dynamics for sweetening of LPG process

Amine treating is the most common system for gas sweetening that is used in petroleum, gas and petrochemical industries. Steady-state analysis of the process is conducted on the developed simulation-model using Aspen Hysys. For obtaining more accurate results, absorber internal specifications and feed gas conditions are taken from real industrial plant data. The effect of the system controlling parameters on concentrations of H2S and CO2 in sweet gas is inspected. The manipulated variables for the amine unit are Di-ethanolamine (DEA) solution circulation rate and temperature. Sour gas flow rate and H2S/CO2 mole ratio in feed become disturbance or load; whereas, the control variables are concentration and throughput of sour gas in exit sweet gas. The outcome of the sensitivity study is used to develop MIMO transient models with a first-order plus dead-time (FOPDT)structure for the control studies. Based on the developed model the model predictive control (MPC) and PID controls are implemented for 2 by 2 systems.

Measurement invariance and country difference in children's social skills development: Evidence from Japanese and Chinese samples.

The diversity of child social skills development is not well detected among Asian countries. Culturally validated assessments are needed for practitioners to evaluate child social skills. This study tested the measurement invariance of the Social Skill Scale (SSS) across Japanese and Chinese samples and explored country differences in child social skills development. The SSS utilizes a widely used factor structure (assertion, self-control, and cooperation subdomains) and has established Japanese and Chinese versions. We conducted investigations with an identical process and materials with different language versions, collecting data from 931 Japanese kindergarten children (Mage = 4.35, SDage = 1.07; 53.6% boys) and from 1130 Chinese kindergarten children (Mage = 4.47, SDage = 1.00; 52.3% boys). We used multiple confirmatory factor analysis to test measurement invariance of the SSS and established the validity, reliability, and scalar measurement invariance for the first-order factor structure of the SSS across the two country samples. We also examined country differences on the associations between demographics, parenting practice, and child social skills development. We found that, compared to the Chinese sample, cooperation skills significantly increased more with age among the Japanese sample. However, spanking was negatively related to self-control skills development in both countries. Our findings contribute to the demonstration of the diversity of child social skills development and have important implications for assessing and developing child social skills using culture-specific strategies.

Typicality à la Russell in Set Theory

We adjust the notion of typicality originated with Russell, which was introduced and studied in a previous paper for general first-order structures, to make it expressible in the language of set theory. The adopted definition of the class ${\rm NT}$ of nontypical sets comes out as a natural strengthening of Russell's initial definition, which employs properties of small (minority) extensions, when the latter are restricted to the various levels $V_\zeta$ of $V$. This strengthening leads to defining ${\rm NT}$ as the class of sets that belong to some countable ordinal definable set. It follows that ${\rm OD}\subseteq {\rm NT}$ and hence ${\rm HOD}\subseteq {\rm HNT}$. It is proved that the class ${\rm HNT}$ of hereditarily nontypical sets is an inner model of ${\rm ZF}$. Moreover the (relative) consistency of $V\neq {\rm NT}$ is established, by showing that in many forcing extensions $M[G]$ the generic set $G$ is a typical element of $M[G]$, a fact which is fully in accord with the intuitive meaning of typicality. In particular it is consistent that there exist continuum many typical reals. In addition it follows from a result of Kanovei and Lyubetsky that ${\rm HOD}\neq {\rm HNT}$ is also relatively consistent. In particular it is consistent that ${\cal P}(\omega)\cap {\rm OD}\subsetneq{\cal P}(\omega)\cap {\rm NT}$. However many questions remain open, among them the consistency of ${\rm HOD}\neq {\rm HNT}\neq V$, ${\rm HOD}={\rm HNT}\neq V$ and ${\rm HOD}\neq {\rm HNT}= V$.

The effects of fault-zone architecture, wall-rock competence and fluid pressure variations on hydrothermal veining and gold mineralization along the Sheba Fault, Barberton Greenstone Belt, South Africa

Hydrothermal vein systems illustrate the spatial and temporal evolution of structural permeabilities along the Sheba Fault, the first-order fault structure in the Sheba-Fairview complex of gold mines in the Archaean Barberton greenstone belt. The fault juxtaposes competent Moodies Group metapsammites against rheologically weaker metaturbidites and intercalated serpentinites of the Fig Tree and Onverwacht groups. Strain localization into the weaker lithologies results in the pronounced asymmetric zonation of the fault into a fault core and a fault-damage zone. The fault core in the weaker Fig Tree and Onverwacht lithologies is characterized by the transposition of earlier bedding and pervasive foliation development. In contrast, hydrothermal veining, alteration and mineralization are confined to competent Moodies Group rocks that form the tens of meter wide damage zone in the immediate footwall of the fault core. Vein systems of the Sheba West ore body disclose the multistage evolution of the fluid flow system along the fault. An early phase of crackle-breccia formation and associated carbonate (dolomite) alteration is regionally widespread and largely pre-dates the main phase of gold mineralization. Crackle breccias are overprinted by successive sets of subhorizontal and subvertical extension (mode I) veins, steeply inclined shear veins and moderately-dipping late-stage cataclasites. The orientation and controls of the vein sets demonstrate their formation during (1) progressive NW-SE directed subhorizontal shortening, and (2) waning fluid pressures from lithostatic values (mode I veins) to sub-lithostatic fluid pressures (mode II shear veins and cataclasites). The economic-grade mineralization of the Sheba West ore body relates to an undulation of the controlling Sheba Fault that corresponds to a releasing bend during top-to-the-NW thrusting. The vein systems along the Sheba Fault illustrate the controls of permeability structures as a result of lithological and rheological contrasts, geometric variations (fault bends) and fluid-pressure fluctuations during faulting.

Measuring Strengths, Opportunities, Aspirations, and Results: Psychometric Properties of the 12-Item SOAR Scale.

Strengths, Opportunities, Aspirations, and Results (SOAR) is a strengths-based framework for strategic thinking, planning, conversations, and leading that focuses on strengths, opportunities, aspirations, and results. The SOAR framework leverages and integrates Appreciative Inquiry (AI) to create a transformation process through generative questions and positive framing. While SOAR has been used by practitioners since 2000 as a framework for generating positive organizational change, its use in empirical research has been limited by the absence of reliable and valid measures. We report on the reliability, construct validity, and measurement invariance of the SOAR Scale, a 12-item self-report survey organized into four first-order factors (Strengths, Opportunities, Aspirations, and Results). Data from a sample of 285 U.S. professionals were analyzed in Mplus using confirmatory factor analysis and exploratory structural equation modeling. The Four-Factor first-order exploratory structure equation modeling (ESEM) had the best model fit. Measurement invariance tests found the scalar invariance of the SOAR Scale across gender and education groups. Implications are discussed for using the SOAR Scale to build resilience at the individual, the team, and the organizational levels.

One Lie Group to Define Them All

We produce a connected real Lie group that, as a first-order structure in the group language, interprets the real field expanded with a predicate for the integers. Moreover, the domain of our interpretation is definable in the group.

Validation of the French version of the moral disengagement in bullying scale: Testing Bandura's conceptual model

Although Bandura conceptualized moral disengagement as a global dimension encompassing a set of mechanisms, the validated factorial structures of the existing scales have not fully matched the conceptual model so far. The present study attempts to narrow the gap between the moral disengagement conceptual model and its measurement tools by testing five factorial structures based both on theory and previous empirical work. A sample of 1107 pupils from Grades 4 to 6 completed the French version of the Moral Disengagement in Bullying Scale (Fr-MDBS). Confirmatory factorial analyses revealed that a second-order factor structure, congruent with the conceptual model, was better than a single-factor and as good as a first-order multi-factorial structure. Results also supported both construct validity (gender comparison) and predictive validity of the scale. Moral disengagement mechanisms were associated with self- and peer-reported bullying and victimization, defender, and outsider behaviors. Euphemistic labeling, diffusion of responsibility, and distorting consequences were also related to bullying whereas moral justification and victim attribution were related to both bullying and victimization. Euphemistic labeling, diffusion of responsibility, distorting consequences, and victim attribution were negatively associated with defender behavior and positively related to outsider behavior. Advantageous comparison was not related to any of the examined variables. The Fr-MDBS seems to be a useful assessment tool to validly examine either the mechanisms or the global dimension of moral disengagement.

Psychometric properties of the Persian version of the Geriatric Anxiety Scale

Aim: The aim of this study was to investigate the psychometric properties of the Persian version of the Elderly Anxiety Scale (GAS). Methods: The research was descriptive. The statistical population included all elderly men and women living in Kahrizak nursing home in Tehran. Among them, 250 people (150 females and 100 males) were selected by available sampling method. The instrument used was the Elderly Anxiety Scale (GAS). Confirmatory factor analysis and Cronbach's alpha reliability and retest coefficient were used to evaluate the validity of the scale structure. Data were analyzed using LISREL and SPSS software. Results: The results showed that the Elderly Anxiety Scale (GAS) in the first-order factor structure was confirmed using confirmatory factor analysis. The retest coefficient obtained from the test was estimated at one-week intervals. The Cronbach's alpha of the whole scale is 0.83 and its retest coefficient is 0.81. Conclusion: It can be concluded that the Persian version of the Elderly Anxiety Scale (GAS) has good validity and reliability and is an effective self-report tool for research purposes in the field of aging.

A Hypergraph Approach for Estimating Growth Mechanisms of Complex Networks

Temporal datasets that describe complex interactions between individuals over time are increasingly common in various domains. Conventional graph representations of such datasets may lead to information loss since higher-order relationships between more than two individuals must be broken into multiple pairwise relationships in graph representations. In those cases, a hypergraph representation is preferable since it can preserve higher-order relationships by using hyperedges. However, existing hypergraph models of temporal complex networks often employ some data-independent growth mechanism, which is the linear preferential attachment in most cases. In principle, this pre-specification is undesirable since it completely ignores the data at hand. Our work proposes a new hypergraph growth model with a data-driven preferential attachment mechanism estimated from observed data. A key component of our method is a recursive formula that allows us to overcome a bottleneck in computing the normalizing factors in our model. We also treat an often-neglected selection bias in modeling the emergence of new edges with new nodes. Fitting the proposed hypergraph model to 13 real-world datasets from diverse domains, we found that all estimated preferential attachment functions deviates substantially from the linear form. This demonstrates the need of doing away with the linear preferential attachment assumption and adopting a data-driven approach. We also showed that our model outperformed conventional models in replicating the observed first-order and second-order structures in these real-world datasets.

Trans-Cultural Validation of the “Physical Education and Sport Anxiety State Scale” (PESAS) in Arabic Language: Insights for Sport and Physical Education

Objective: Adaptation in Arabic language and empirical examination of the instrument for measuring the state anxiety in physical education and sport PSEAS among Tunisian students. Methods: A set of 623 athletic and non-athletic students (m age = 14.71, AND age = 2) from primary and secondary school completed an adapted version of the PSEAS Anxiety Scale in Arabic language. The subjects were recruited in two phases: exploratory (n = 161; m age = 14.59, ET age = 2) and confirmatory (n = 462; m age = 14.79, ET age = 1.99). Results: The PSESAS measurement scale was stable on exploratory factor analysis and no items were removed from the three dimensions of the scale. Likewise, reliability tests have shown that the internal consistency is adequate. The confirmatory factor analysis carried out showed the robustness of the measurement of the 18 items of the scale. Also, the three dimensions showed a moderate correlation, which confirms the first-order structure of the instrument. The sensitivity of the instrument for the variable gender, sport practice and gender interaction effect*sport practice was highlighted. Females and non-athletes showed higher levels of anxiety. Conclusion: The Arabic version of PSEAS is valid and reliable in terms of psychometrics and can be administered to assess state anxiety rates for primary and secondary students in physical education in Arab countries.

The Effect of a Single Dose of Thiamine on Oxygen Consumption in Patients Requiring Mechanical Ventilation for Acute Illness: A Phase II, Randomized, Double-Blind, Placebo-Controlled Trial.

IMPORTANCE:Lower oxygen consumption is associated with worse survival in septic shock and in other forms of critical illness. No treatment that increases oxygen extraction, a key determinant of oxygen consumption, has been found. Thiamine is required for aerobic metabolism, and deficiency is common in the critically ill.OBJECTIVES:We evaluated the effect of thiamine on oxygen consumption in patients requiring mechanical ventilation for an acute illness.DESIGN:Phase II, randomized, double-blind, and placebo-controlled trial.SETTING AND PARTICIPANTS:ICUs in a tertiary care hospital in the United States. Patients admitted to the ICU and requiring mechanical ventilation were screened for enrollment.INTERVENTIONS:After enrollment, baseline measurement of oxygen consumption and baseline laboratories including lactate, central venous oxygen saturation, and pyruvate dehydrogenase, a single dose of 200 mg IV thiamine or placebo was administered. Oxygen consumption was then monitored for 6 additional hours and repeat laboratories were drawn at the end of the protocol.MAIN OUTCOMES AND MEASURES:The primary outcome was the change in oxygen consumption. Analysis was done using linear regression with a first-order autoregressive variance-covariance structure to account for repeated measures within subjects. Secondary outcomes included change in lactate, central venous oxygen saturation, and pyruvate dehydrogenase quantity and activity.RESULTS:Sixty-seven patients were enrolled. After excluding 11 patients due to inadequate quantity or quality of oxygen consumption data, 56 patients were included. There was no difference in change in oxygen consumption in the 6 hours after study drug. Results for secondary outcomes were similarly negative. In the prespecified subgroup of 18 thiamine deficient patients, there was a difference in the two oxygen consumption curves (p = 0.006), although no difference in median oxygen consumption or area under the curve.CONCLUSIONS AND RELEVANCE:A single dose of IV thiamine did not alter oxygen consumption in patients requiring mechanical ventilation for acute illness.

Health-related quality of life in women with endometriosis: psychometric validation of the Endometriosis Health Profile 30 questionnaire using confirmatory factor analysis.

STUDY QUESTIONWhich of the competing models of the Endometriosis Health Profile 30 Questionnaire (EHP-30) factor structure is best supported by confirmatory factor analysis (CFA)?SUMMARY ANSWERFindings support a five-factor first-order model of the EHP-30, thereby lending support to the model originally suggested by the questionnaire developers.WHAT IS KNOWN ALREADYEndometriosis has a negative impact on quality of life, and measures specifically developed to address this impact, such as the EHP-30, are vital in research and disease management. Previous studies have found different models of the EHP-30 factor structure, and generated uncertainty regarding how to use the questionnaire. CFA can be applied to compare competing factor models and determine the underlying structure of a questionnaire.STUDY DESIGN, SIZE, DURATIONThis cross-sectional multicenter study included 304 women with endometriosis recruited from three different public health service endometriosis clinics (referral centers for treatment of severe endometriosis) and the Danish Endometriosis Patients Association from 2014 to 2015.PARTICIPANTS/MATERIALS, SETTING, METHODSDiagnosis of endometriosis was confirmed in medical records for 84.2% and by histology for 66.8% of participants. Questionnaires (the licensed Danish version of the EHP-30) were sent by post two times with a 6- to 12-week interval. CFA was used to examine construct validity and Bland–Altman plots to examine test–retest reliability and the convergent validity with the Short Form 36 version 2.MAIN RESULTS AND THE ROLE OF CHANCEResponse rate was high (87.6%). CFA supported the original first-order five-factor structure of the EHP-30, and thereby, the use of five separate scale-scores in clinical and research practice. Visual inspection of Bland–Altman plots suggested excellent test–retest reliability of the EHP-30 and supported the use of a disease specific quality of life instrument for women with endometriosis.LIMITATIONS, REASONS FOR CAUTIONDiagnosis could not be confirmed through histology data in 33.2% of participants. However, subgroup analyses based on women with confirmed histology only, yielded similar results. Data related to menstrual cycle stage and the use of hormonal and pain medication during questionnaire completion were not collected. A larger study, including data from different countries on different continents, would be better designed to exclude potential population bias.WIDER IMPLICATIONS OF THE FINDINGSEHP-30, with its original five-factor structure, appears to be a valid, stable, and specific quality of life measure for women with endometriosis. It seems easy to understand, quick to administer, and importantly, scoring might be unaffected by cyclical/menstrual pain symptoms related to endometriosis. The finding of a five-factor model from different studies across several countries supports the crosscultural validity of the EHP-30.STUDY FUNDING/COMPETING INTEREST(S)This work was supported by the Danish Endometriosis Association, which is a nongovernmental organization run by women with endometriosis and by a scholarship from the Health Research Fund of Central Denmark Region. The authors have no conflicts of interest.TRIAL REGISTRATION NUMBERThe Danish Data Protection Agency (J.nr: 2013-41-2264).

High-pressure monoclinic phase of MoAlB

The pressure-induced phase transitions of MoAlB have been fully studied to provide insights into the typical MAB phases under high pressure. A novel high-pressure monoclinic structure (C2/m, Z = 4) was firstly identified for the MoAlB above 234 GPa, using the first principles crystal structure prediction approach. First-order structure transition character of MoAlB from the ambient-pressure orthorhombic Cmcm phase to this high-pressure monoclinic C2/m phase was demonstrated by a volume drop of 1.28%. Inspections of crystal structures showed that the occurrence of C2/m phase follows the slip in the metallic Al-Al layers and the fracture of linear zigzag B-B chains in the Cmcm phase under compression, confirming the earlier reports. Our argument has been also supported by the softening of elastic constant under high pressure. Phonon curves calculations suggest the high-pressure C2/m phase can be quenchable to ambient pressure. The electronic and mechanical properties of this novel C2/m phase have thus been systematically investigated.

Applicability and validation of the Reaction to Tests Scale (RTT) in a sample of Portuguese medical students

BackgroundTest anxiety is a crucial factor in determining academic outcomes, and it may lead to poor cognitive performance, academic underachievement, and psychological distress, interfering specifically with their ability to think and perform during tests. The main objective of this study was to explore the applicability and psychometric properties of a Portuguese version of the Reactions to Tests scale (RTT) in a sample of medical students.MethodA sample of 672 medical students completed the RTT. The sample was randomly split in half to allow for independent Exploratory Factor Analysis (EFA) and to test the best fit model—Confirmatory Factor Analysis (CFA). CFA was used to test both the first-order factor structure (four subscales) and second-order factor structure, in which the four subscales relate to a general factor, Test Anxiety. The internal consistency of the RTT was assessed through Cronbach’s alpha, Composite reliability (CR) and Average Variance Extracted (AVE) for the total scale and each of the four subscales. Convergent validity was evaluated through the correlation between RTT and the State-Trait Anxiety Inventory (STAI-Y).To explore the comparability of measured attributes across subgroups of respondents, measurement invariance was also studied.ResultsResults from exploratory and confirmatory factor analyses showed acceptable fits for the Portuguese RTT version. Concerning internal consistency, results indicate that RTT was found to be reliable to measure test anxiety in this sample. Convergent validity of the RTT with both state and trait anxiety STAI-Y’s subscales was also shown. Moreover, multigroup analyses showed metric invariance across gender and curriculum phase.ConclusionOur results suggest that the RTT scale is a valid and reliable instrument for the measurement of test anxiety among Portuguese Medical Students.