Mean Hitting Time for Random Walks on a Class of Sparse Networks

For random walks on a complex network, the configuration of a network that provides optimal or suboptimal navigation efficiency is meaningful research. It has been proven that a complete graph has the exact minimal mean hitting time, which grows linearly with the network order. In this paper, we present a class of sparse networks G(t) in view of a graphic operation, which have a similar dynamic process with the complete graph; however, their topological properties are different. We capture that G(t) has a remarkable scale-free nature that exists in most real networks and give the recursive relations of several related matrices for the studied network. According to the connections between random walks and electrical networks, three types of graph invariants are calculated, including regular Kirchhoff index, M-Kirchhoff index and A-Kirchhoff index. We derive the closed-form solutions for the mean hitting time of G(t), and our results show that the dominant scaling of which exhibits the same behavior as that of a complete graph. The result could be considered when designing networks with high navigation efficiency.

Beyond Tribadism: Alternate Discourses on Female Homoeroticism in Greek and Latin Literature

<p>Scholarly accounts of sexuality in the ancient world have placed much emphasis on the normative dichotomy of activity and passivity. In the case of female homoeroticism, scholars have focussed largely on the figure of the so-called tribas, a masculinised, aggressively penetrative female who takes the active role in sexual relations with women. My thesis seeks to set out a wider conceptualisation of female homoeroticism that encompasses erotic sensuality between conventionally feminine women. The first chapter surveys previous scholarship on ancient sexuality and gender and on female homoeroticism in particular, examining the difficulties in terminology and methodology inherent in such a project. The second chapter turns to the Callisto episode in Ovid’s Metamorphoses, beginning with the kiss between the huntress Callisto and Jupiter, who is disguised as Callisto’s patron goddess Diana. The Callisto episode contains hints of previous intimacy between Callisto and Diana, and the kiss scene can be read as an erotic interaction between the two, both of whom are portrayed as conventionally feminine rather than tribadic. The third chapter examines several Greek intertexts for the Callisto episode: Callimachus’ hymns to Athena and Artemis, and the story of Leucippus as narrated by Parthenius and Pausanias. These narratives exhibit a similar dynamic to the Callisto episode, in that they eroticise the relationships both between Diana and her companions and amongst those companions. An educated reader of Ovid’s Metamorphoses would plausibly have had these Greek texts in mind, and would thus have been more likely to read the relationship between Diana and Callisto as homoerotic. Finally, the fourth chapter approaches Statius’ Achilleid from the perspective of female homoeroticism, a move without precedent in past scholarship. The relationship between Deidameia and the cross-dressed Achilles engages intertextually with the Callisto episode, presenting another exclusively female-homosocial environment in which homoerotic desires can flourish.</p>

Beyond Tribadism: Alternate Discourses on Female Homoeroticism in Greek and Latin Literature

<p>Scholarly accounts of sexuality in the ancient world have placed much emphasis on the normative dichotomy of activity and passivity. In the case of female homoeroticism, scholars have focussed largely on the figure of the so-called tribas, a masculinised, aggressively penetrative female who takes the active role in sexual relations with women. My thesis seeks to set out a wider conceptualisation of female homoeroticism that encompasses erotic sensuality between conventionally feminine women. The first chapter surveys previous scholarship on ancient sexuality and gender and on female homoeroticism in particular, examining the difficulties in terminology and methodology inherent in such a project. The second chapter turns to the Callisto episode in Ovid’s Metamorphoses, beginning with the kiss between the huntress Callisto and Jupiter, who is disguised as Callisto’s patron goddess Diana. The Callisto episode contains hints of previous intimacy between Callisto and Diana, and the kiss scene can be read as an erotic interaction between the two, both of whom are portrayed as conventionally feminine rather than tribadic. The third chapter examines several Greek intertexts for the Callisto episode: Callimachus’ hymns to Athena and Artemis, and the story of Leucippus as narrated by Parthenius and Pausanias. These narratives exhibit a similar dynamic to the Callisto episode, in that they eroticise the relationships both between Diana and her companions and amongst those companions. An educated reader of Ovid’s Metamorphoses would plausibly have had these Greek texts in mind, and would thus have been more likely to read the relationship between Diana and Callisto as homoerotic. Finally, the fourth chapter approaches Statius’ Achilleid from the perspective of female homoeroticism, a move without precedent in past scholarship. The relationship between Deidameia and the cross-dressed Achilles engages intertextually with the Callisto episode, presenting another exclusively female-homosocial environment in which homoerotic desires can flourish.</p>

Novel Concept for Electro-Hydrostatic Actuators for Motion Control of Hydraulic Manipulators

Self-contained hydraulic cylinders have gained popularity in the recent years but have not been implemented for high power articulated hydraulic manipulators. This paper presents a novel concept for an electro-hydrostatic actuator applicable to large hydraulic manipulators. The actuator is designed and analyzed to comply with requirements such as load holding, overload handling, and differential flow compensation. The system is analyzed during four quadrant operation to investigate energy efficiency and regenerative capabilities. Numerical simulation is carried out using path control and 2DOF anti-swing of a hydraulic crane as a load case to illustrate a real world scenario. A comparison with traditional valve-controlled actuators is conducted, showing significantly improved efficiency and with similar dynamic response, as well as the possibility for regenerating energy.

The Influence of Cork and Manufacturing Parameters on the Properties of Cork–Rubber Composites for Vibration Isolation Applications

The addition of cork to a natural rubber compound and the vulcanization parameters were studied in terms of their influence on the properties of cork–rubber materials. The characterization of different compounds was carried out and included in the determination of mechanical properties related to the application of cork–rubber composites as vibration isolation pads, such as static and dynamic behavior under compressive loading. Statistical methods, such as ANOVA and regression analysis, were used in this study. The results showed that the introduction of cork as an additional filler in the studied rubber compound increased its hardness and static stiffness, while maintaining a similar dynamic behavior to the base rubber compound when subjected to compressive loading. In addition, it was found that increasing the amount and granulometry of cork and lower vulcanization temperatures resulted in stiffer vulcanizates. Materials with higher cork granule contents were found to be affected in their final properties by molding pressure. A study involving the use of linear regression models as a tool to predict or optimize properties related to vibration isolation applications was also developed.

Improving enterprise’s competitiveness on the basis of combined ABC/XYZ and cluster analyses of the commodity nomenclature

Subject. This article examines the relationship between marketing activities and the development of entrepreneurial structures in Russia. Objectives. The article aims to develop a methodological approach that helps optimize the product nomenclature and develop differentiated marketing strategies for managing sales in different segments. Methods. For the study, I used the methods of ABC/XYZ and cluster analyses. Results. The article offers a methodological approach to the analysis of the nomenclature of goods, tested on the data of one of the business structures of the Crimean wine industry. It identifies goods nomenclature clusters that have similar dynamic characteristics for changes in sales volumes and demand predictability, and provides recommendations for increasing sales, margins, and improving enterprise competitiveness. Conclusions. The developed methodological approach can be considered as an element of information and methodological support for the enterprise competitiveness management system.

TLR4 signaling in the development of colitis-associated cancer and its possible interplay with microRNA-155

Ulcerative colitis (UC) has closely been associated with an increased risk of colorectal cancer. However, the exact mechanisms underlying colitis-associated cancer (CAC) development remain unclear. As a classic pattern-recognition receptor, Toll like receptor (TLR)4 is a canonical receptor for lipopolysaccharide of Gram-negative bacteria (including two CAC-associated pathogens Fusobacterium nucleatum and Salmonella), and functions as a key bridge molecule linking oncogenic infection to colonic inflammatory and malignant processes. Accumulating studies verified the overexpression of TLR4 in colitis and CAC, and the over-expressed TLR4 might promote colitis-associated tumorigenesis via facilitating cell proliferation, protecting malignant cells against apoptosis, accelerating invasion and metastasis, as well as contributing to the creation of tumor-favouring cellular microenvironment. In recent years, considerable attention has been focused on the regulation of TLR4 signaling in the context of colitis-associated tumorigenesis. MicroRNA (miR)-155 and TLR4 exhibited a similar dynamic expression change during CAC development and shared similar CAC-promoting properties. The available data demonstrated an interplay between TLR4 and miR-155 in the context of different disorders or cell lines. miR-155 could augment TLR4 signaling through targeting negative regulators SOCS1 and SHIP1; and TLR4 activation would induce miR-155 expression via transcriptional and post-transcriptional mechanisms. This possible TLR4-miR-155 positive feedback loop might result in the synergistic accelerating effect of TLR4 and miR-155 on CAC development.

Remdesivir MD Simulations Suggest a More Favourable Binding to SARS-CoV-2 RNA Dependent RNA Polymerase Mutant P323L Than Wild-Type

SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) protein is the target for the antiviral drug Remdesivir (RDV). With RDV clinical trials on COVID-19 patients showing a reduced hospitalisation time. During the spread of the virus, the RdRp has developed several mutations, with the most frequent being A97V and P323L. The current study sought to investigate whether A97V and P323L mutations influence the binding of RDV to the RdRp of SARS-CoV-2 compared to wild-type (WT). The interaction of RDV with WT-, A97V-, and P323L-RdRp were measured using molecular dynamic (MD) simulations, and the free binding energies were extracted. Results showed that RDV that bound to WT- and A97V-RdRp had a similar dynamic motion and internal residue fluctuations, whereas RDV interaction with P323L-RdRp exhibited a tighter molecular conformation, with a high internal motion near the active site. This was further corroborated with RDV showing a higher binding affinity to P323L-RdRp (−24.1 kcal/mol) in comparison to WT-RdRp (−17.3 kcal/mol). This study provides insight into the potential significance of administering RDV to patients carrying the SARS-CoV-2 P323L-RdRp mutation, which may have a more favourable chance of alleviating the SARS-CoV-2 illness in comparison to WT-RdRp carriers, thereby suggesting further scientific consensus for the usage of Remdesivir as clinical candidate against COVID-19.

Economic growth and tourism performance in Latin America and the Caribbean

Since the growing interest in the study of the dynamics of tourism and its implications for economic growth, this paper explores the Latin America and the Caribbean case. From the economic regimes’ conception and time series symbolization, we perform a cluster analysis and a posterior causality relationship estimation between economic growth and tourism performance for 22 countries of Latin America and the Caribbean considering the period between 1995 and 2015. Results show the existence of two clusters of countries with similar dynamic behaviour within them. The estimations show a positive causal and unidirectional relationship from economic growth to the tourism industry in the low-performing tourism cluster, and also a positive and bidirectional causal relationship in the high-performing tourism one. JEL codes: C33; C36; Z32.