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Mapping the network of Shiʿi clerical relations in the Middle East:an analytical approach
Get PDFWhile Shiʿi clerics are among the most influential political actors in the Middle East today, there remains insufficient understanding of the network of relationships that links them together and shapes their politics. This article argues that to understand the politics of Shiʿi clerical elites in the contemporary Middle East requires an historical and sociological grasp of the internal dynamics of Shiʿi leadership, and how and why individual clerics emerge as the top Shiʿi leaders (marjaʿiyya). Little is known about these internal dynamics because there has been little if any systematic study of how individuals within the clerical elite move up through the clerical hierarchy, what shapes the legacy they bring with them, and how this legacy influences their politics. Without this knowledge, it is difficult to fully understand where, when, and how new leaders will arise, and what impact they are likely to have on the politics of the societies in which they are based, and beyond. To illuminate these dynamics and better understand the influence of this important group of actors, this article proposes an approach that aims to map the interconnected world of the Shiʿi clergy using quantitative network analysis. It argues that network analysis can complement existing qualitative studies by illuminating latent connections among the Shiʿi clergy; and, ultimately, can offer a more authoritative foundation for forecasting the identity and politics of future Shiʿi marjaʿiyya
Unilateral Stability in Matching Problems
Get PDFThe canonical solution concept used in matching problems is pairwise stability, whose premise is that harmony is disrupted by any two agents intentionally leaving their partners to be with each other. We instead focus on scenarios in which harmony is disrupted merely by a single agent unilaterally initiating contact with a member of a different pair, whether or not his approach is reciprocated. A variety of solution concepts are proposed in which taboos, status, or power systematically limit such initiatives in order to achieve harmony
Cross-cultural validation of the Revised Green et al., Paranoid Thoughts Scale
Get PDFBackground. With efforts increasing worldwide to understand and treat paranoia, there is a pressing need for culturally valid assessments of paranoid beliefs. The recently developed Revised Green et al. Paranoid Thoughts Scale (R-GPTS) constitutes an easy to administer self-report assessment of mild ideas of reference and more severe persecutory thoughts. Moreover, it comes with clinical cut-offs for increased usability in research and clinical practice. With multiple translations of the R-GPTS already available and in use, a formal test of its measurement invariance is now needed.Methods. Using data from a multinational cross-sectional online survey in the UK, USA, Australia, Germany, and Hong Kong (N=2510), we performed confirmatory factory analyses on the R-GPTS and tested for measurement invariance across sites.Results. We found sufficient fit for the two-factor structure (ideas of reference, persecutory thoughts) of the R-GPTS across cultures. Measurement invariance was found for the persecutory thoughts subscale, indicating that it does measure the same construct across the tested samples in the same way. For ideas of reference, we found no scalar invariance, which was traced back to (mostly higher) item intercepts in the Hong Kong sample.Conclusion. We found sufficient invariance for the persecutory thoughts scale, which is of substantial practical importance, as it is used for the screening of clinical paranoia. A direct comparison of the ideas of reference sum-scores between cultures, however, may lead to an over-estimation of these milder forms of paranoia in some (non-western) cultures
Morphological and molecular evidence for considering Xylocopa nigrocincta as the senior synonym of Xylocopa suspecta (Apidae: Xylocopini)
Get PDFXylocopa nigrocincta Smith, 1854, and Xylocopa suspecta Moure & Camargo, 1988, are two nominal species within the subgenus Neoxylocopa and have a sympatric geographic distribution in South America. While X. nigrocincta is recognized by the presence of reddish metasomatic bands, X. suspecta is entirely black. Although morphologically distinct in terms of metasomal band colour, other morphological characters suggest that both species could be the same evolutionary entity and therefore synonymous. The aim of this research was to review both nigrocincta and suspecta morphotypes using an integrative approach (morphological and molecular) to evaluate if they are truly two different evolutionary lineages. Females of both species were obtained from field collections and museums, representing a large part of their morphotype distribution. Additional diagnostic characters of the external morphology were investigated, such as metasomal band colour, metasomal punctuation, wing colours, and apical regions of the basitibial plate. Mitochondrial gene sequences (COI and CytB) were used for phylogenetic reconstructions. Our results showed that both nigrocincta and suspecta morphotypes are undistinguished based on morphology, although the metasomal band colour, together with the geographic distribution, revealed the presence of three distinct morphogroups, including an intermediate one with a variable number of reddish bands. Nonetheless, the three morphogroups are not supported by molecular data and therefore represent intra-specific variations. In conclusion, our results do not support the hypothesis that the two nominal species are distinct evolutionary lineages, and we propose a synonym between X. nigrocincta and X. suspecta
Optomechanically Induced Transparency/Absorption in a 3D Microwave Cavity Architecture at Ambient Temperature
Get PDFLeveraging advancements in cavity optomechanics, we explore Optomechanically Induced Transparency/Absorption (OMIT/OMIA) in the microwave domain at ambient temperature. Contrary to previous studies employing cryogenic temperatures, this work exploits a 3D microwave cavity architecture to observe these effects at ambient temperature, broadening the scope of possible applications. The work successfully enhances the optomechanical coupling strength, enabling observable and robust OMIT/OMIA effects, and demonstrating up to 25 dB in signal amplification and 20 dB in attenuation. Operating in the unresolved sideband regime enables tunability across a wider frequency range, enhancing the system’s applicability in signal processing and sensing. The findings herein highlight the potential of optomechanical systems, presenting a simplified, cost-effective, and more feasible approach for applications at ambient temperature
Comparison of histological delineations of medial temporal lobe cortices by four independent neuroanatomy laboratories
Get PDFThe medial temporal lobe (MTL) cortex, located adjacent to the hippocampus, is crucial for memory and prone to the accumulation of certain neuropathologies such as Alzheimer's disease neurofibrillary tau tangles. The MTL cortex is composed of several subregions which differ in their functional and cytoarchitectonic features. As neuroanatomical schools rely on different cytoarchitectonic definitions of these subregions, it is unclear to what extent their delineations of MTL cortex subregions overlap. Here, we provide an overview of cytoarchitectonic definitions of the entorhinal and parahippocampal cortices as well as Brodmann areas (BA) 35 and 36, as provided by four neuroanatomists from different laboratories, aiming to identify the rationale for overlapping and diverging delineations. Nissl-stained series were acquired from the temporal lobes of three human specimens (two right and one left hemisphere). Slices (50 μm thick) were prepared perpendicular to the long axis of the hippocampus spanning the entire longitudinal extent of the MTL cortex. Four neuroanatomists annotated MTL cortex subregions on digitized slices spaced 5 mm apart (pixel size 0.4 μm at 20× magnification). Parcellations, terminology, and border placement were compared among neuroanatomists. Cytoarchitectonic features of each subregion are described in detail. Qualitative analysis of the annotations showed higher agreement in the definitions of the entorhinal cortex and BA35, while the definitions of BA36 and the parahippocampal cortex exhibited less overlap among neuroanatomists. The degree of overlap of cytoarchitectonic definitions was partially reflected in the neuroanatomists' agreement on the respective delineations. Lower agreement in annotations was observed in transitional zones between structures where seminal cytoarchitectonic features are expressed less saliently. The results highlight that definitions and parcellations of the MTL cortex differ among neuroanatomical schools and thereby increase understanding of why these differences may arise. This work sets a crucial foundation to further advance anatomically-informed neuroimaging research on the human MTL cortex
The sigma invariants for the golden mean Thompson group
Get PDFWe use a method of Bieri, Geoghegan and Kochloukova to calculate the BNSR-invariants for the Golden-Mean Thompson’s group. To do so we establish conditions under which the Sigma invariants coincide with those of a subgroup of finite index, addressing a problem posed by Strebel
Privacy-Preserving Authentication: A Homomorphic Encryption Approach
Get PDFThe importance of privacy for individuals has become increasingly evident in recent years as the amount of personal data being collected, stored and used by both private companies and government institutions has grown exponentially. The potential for this data to be misused or mishandled has led to widespread concern among individuals about the protection of their personal information. In response to these concerns, there has been a rise in the development of privacy-preserving technologies, which aim to protect personal data while still allowing it to be used for legitimate purposes. These technologies are necessary not only to address the concerns of individuals, but also to meet the legal requirements of institutions that handle personal information. Many applications using personal information as a commodity can benefit from privacy-preserving technologies. The research presented in this thesis targets a commonly used Internet application in which privacy-enhancing technologies can play a key role: biometric-based authentication. Authentication is the establishment of one party’s identity to the other. Biometric data, such as faces, fingerprints or iris, are used more and more commonly as a means of providing personal identification and authentication. However, authentication protocols using biometric data face serious privacy concerns, as the data involved is sensitive or personally-identifiable, which makes it necessary for data holders to protect its privacy. The widespread use of this application, and the need to protect user privacy, motivated us to examine how homomorphic encryption, a privacy-preserving technology, can be used and deployed to enhance privacy in such an application. Homomorphic encryption is a form of encryption that allows arbitrary computations to be performed on encrypted data, resulting in an encrypted result that, when decrypted, is the same as if the computation had been performed on the corresponding cleartext data. This means that entire computational processes can be executed on encrypted data without requiring the decryption key, thereby maintaining the privacy of the data involved. This can address both concerns from individuals regarding the protection of their personal and sensitive data, and legal requirements that institutions must meet. Homomorphic encryption can be used in an authentication protocol to allow a server to verify the authenticity of a client’s credentials without having access to the cleartext values of the credentials. In this thesis, we describe and prove secure two novel biometric-based authentication protocols that use homomorphic encryption to preserve the confidentiality of the biometric data both in storage and during use. These protocols ensure the privacy of the biometric information, while still allowing it to be used for authentication purposes. Users of the protocols encrypt their own biometric data and send it to a remote server that performs computations, including the biometric matching, solely on encrypted data. One of the protocols is designed to protect biometric data privacy against a honest-but-curious server and the other against a malicious server. Additionally, in both cases the user is securely authenticated by the server. For both the protocols, implementation and performance results using public homomorphic encryption libraries are presented along with a security and usability assessment, including an evaluation analysis against industry-standard biometric-based authentication schemes. In the most efficient implementation, the active authentication phase takes no more than three seconds to complete
The Influence of Technology Use on Learning Skills Among Generation Z:A Gender and Cross-country Analysis
Get PDFThis inquiry flags the shortage of evidence on the distinctive effect of technology use on defined learning skills. To tackle this inertia, it identifies (1) video gaming, (2) internet searching and (3) smartphone usage as ubiquitous forms of technology. Then, it characterises (1) abstract conceptualisation, (2) concrete experience and (3) reflective observation and active experimentation as dominant learning skills. Investigating a Nigeria and UK sample of 240 generation Z students, the associations are examined alongside the effects of gender and country. Based on a structural equation model, the analysis showed that although alternate uses of technology have mostly significant influences, their impact is largely negative with only internet searching having a positive effect on learning. The findings are explained through a cognitive load lens and insights are offered to learning providers to temper the appetite for technology use in instructional designs with thought and caution
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