Searching for superspreaders of information in real-world social media

A number of predictors have been suggested to detect the most influential spreaders of information in online social media across various domains such as Twitter or Facebook. In particular, degree, PageRank, k-core and other centralities have been adopted to rank the spreading capability of users in information dissemination media. So far, validation of the proposed predictors has been done by simulating the spreading dynamics rather than following real information flow in social networks. Consequently, only model-dependent contradictory results have been achieved so far for the best predictor. Here, we address this issue directly. We search for influential spreaders by following the real spreading dynamics in a wide range of networks. We find that the widely-used degree and PageRank fail in ranking users' influence. We find that the best spreaders are consistently located in the k-core across dissimilar social platforms such as Twitter, Facebook, Livejournal and scientific publishing in the American Physical Society. Furthermore, when the complete global network structure is unavailable, we find that the sum of the nearest neighbors' degree is a reliable local proxy for user's influence. Our analysis provides practical instructions for optimal design of strategies for "viral" information dissemination in relevant applications.Comment: 12 pages, 7 figure

Statistical Methods for Targeted Clinical Trials under Enrichment Design

Background/PurposeAfter completion of the Human Genome Project, disease targets at the molecular level can be identified. Treatment for these specific targets can be developed with the individualized treatment of patients becoming a reality. However, the accuracy of diagnostic devices for molecular targets is not perfect and statistical inference for treatment effects of the targeted therapy is biased. We developed statistical methods for an unbiased inference for the targeted therapy in patients who truly have the molecular targets.MethodsUnder the enrichment design, for binary data, we propose using the expectation maximization (EM) algorithm with the bootstrap method, to incorporate the inaccuracy of the diagnostic device for detection of the molecular targets for inference of the treatment effects. A simulation study was conducted to empirically investigate the performance of the proposed estimation and testing procedures. A numerical example illustrates the application of the proposed method.ResultsSimulation results demonstrated that the proposed estimation method was unbiased, with adequate precision, and the confidence interval provided satisfactory coverage probability. The proposed testing procedure adequately controlled the size with sufficient power. The numerical example showed that a statistically significant treatment effect could be obtained when the inaccuracy of the diagnostic device was taken into account.ConclusionOur proposed estimation and testing procedures are adequate statistical methods for the inference of the treatment effect for patients who truly have the molecular targets

Detection of a Deep Flaw Inside a Conductor Using a Squid Magnetometer

In general, eddy current techniques are suitable for finding surface-breaking flaws in conductors. Subsurface cracks are very difficult to detect due to the skin depth effect. Acoustic techniques are effective at detecting subsurface voids, but cracks immediately beneath the surface are difficult to discriminate from the surface signal. Superconducting QUantum Interference Device (SQUID) magnetometers, very sensitive instruments for measuring DC and low frequency fields, have been used for detection of flaws in conducting objects [1,2,3]. By injecting DC and low frequency AC currents into a brass bar, we have detected a subsurface flaw using a SQUID magnetometer, and shown these data to be consistent with our theoretical calculation

Personality, interpersonal identification and agent's performance in Multilevel Marketing Industry (MLM): preliminary

Purpose-This paper aims to explore the influence of personality traits on agent's performance in MLM industry based in Malaysia, taking into consideration the mediating role of interpersonal identification. Design/methodology/approach-The Big Five Factors (BFF) of personality traits was used in this paper. Previous research and literature is reviewed to establish current practices and point to gaps to be filled to meet the market needs. This paper proposed a framework with interpersonal identification as a mediating factor of agent's performance. Findings-The Multilevel Marketing (MLM) industry faces challenges in attracting and maintaining agents in their roles. The big five factors alone cannot effectively explain agents. Agent's interpersonal identification can play a significant mediating role in the big five-factor framework in predicting agent's performance. It is important for industry and academia to work collaboratively to educate the general public on the rewards and benefits of working in the MLM industry. Practical implications-Adopting strategies described in this study may contribute to social change by increasing the success rate among multilevel marketers, thus reducing unemployment, and producing a positive effect on the economy. Originality/value-This paper adds value and contributes to the MLM industry and academia, as it represents current research and thought processes from both the academic community and the practitioners (sales managers, executives, supervisors, human resources managers). The proposed framework in this paper helps researcher by providing a tool for systematic evaluation and testing of real empirical situation of agent's performance

Lithics in the West: Using Lithic Analysis to Solve Archeological Problems in Western North America

Lithics in the West seeks to link the rich archaeological lithic data base from the western United States with some of the contemporary theoretical and analytical approaches used in global settings in stone tool and debitage analysis today. The book highlights the role that lithic analysis (in all its forms) plays in solving research problems in the prehistory of western North America. The book covers important archaeological sites and projects in Montana, Wyoming, Idaho, Colorado, and Washington. Contributors include William Andrefsky, Jr., Robert Kelly, Nicole Waguespack, Pei-Lin Yu, Doug MacDonald, Robert Brunswig, Scott Carpenter, Jackie Cook, David Diggs, Philip Fisher, Katie Harris, Brian Ostahowski, Mary Prasciunas, Ken Reid, and Todd Surovell.https://scholarworks.umt.edu/umpress-oabooks/1000/thumbnail.jp

Insights into iguanodontian dental architecture from an Early Cretaceous Chinese basal hadrosauriform maxilla (Ornithischia: Iguanodontia)

Basal hadrosauriform iguanodontian dinosaurs have been invaluable towards understanding the evolution of the complex and highly efficient advanced hadrosauriform tooth battery dental system. Here we report a new basal hadrosauriform maxilla specimen - IVPP V22529 - from the Dashuiguo Formation of Maortu, Nei Mongol, China that preserves a corrugated middle ventrolateral margin that differs from the straight and undulating ventral margins found in most iguandontian and non-iguanodontian dinosaurs. The uniqueness of this ventrolateral margin relates to a new dental structure - cementum ‘jackets’ that wrap about the labial sides of the teeth. To our knowledge this is the first time that cementum has been described migrated onto the tooth crowns of iguandontians (and other dinosaurs), but this trait is common amongst mammals. This dental morphology - seen in a similar form in the basal hadrosauriform Equijubus – therefore broadens our knowledge of iguanodontian maxillary anatomy and shows that the basal hadrosauriform dental system was more morphologically complex than previously thought. IVPP V22529 resembles maxillae specimens of Probactrosaurus gobiensis, a contemporaneous taxon known from the same locality in North China, in sharing an inferred subtriangular shape, a relatively flat lateral surface bearing a low row of foramina as well as similar-looking teeth. However, the presence of a unique corrugated middle ventrolateral margin in IVPP V22529, a low row of foramina on its lateral surface that also open anteriorly and increase in size posteriorly as well as a prominent medial shelf suggests that this specimen does not belong to P. gobiensis. However, these differences could conceivably be related to ontogenetic and sexual variation, which have not been fully documented in P. gobiensis. More detailed comparisons of IVPP V22529 and Probactrosaurus are also hampered by the missing posterior portion of IVPP V22529 as well as the missing anterior ramii in Probactrosaurus maxillae specimens. It is clear though that IVPP V22529 is different from the more advanced Northern Chinese hadrosauriforms Bactrosaurus and Gilmoreosaurus. The latter lack well-developed maxillary grooves on their medial shelves, unlike IVPP V22529, but all three taxa possess less-developed ones on the medial surfaces of the anteromedial processes of the anterior ramii. Different to IVPP V22529, Gilmoreosaurus also has foramina that are more highly-positioned on the lateral surface of its maxilla as well as a row of larger and more circular ‘special’ foramina on its medial surface. Thus, at this time, IVPP V22529 is identified as a basal hadrosauriform and not as a new genus or as a new species of Probactrosaurus.published_or_final_versio

Relationship Between Foveal Cone Specialization and Pit Morphology in Albinism

Purpose.Albinism is associated with disrupted foveal development, though intersubject variability is becoming appreciated. We sought to quantify this variability, and examine the relationship between foveal cone specialization and pit morphology in patients with a clinical diagnosis of albinism. Methods. We recruited 32 subjects with a clinical diagnosis of albinism. DNA was obtained from 25 subjects, and known albinism genes were analyzed for mutations. Relative inner and outer segment (IS and OS) lengthening (fovea-to-perifovea ratio) was determined from manually segmented spectral domain-optical coherence tomography (SD-OCT) B-scans. Foveal pit morphology was quantified for eight subjects from macular SD-OCT volumes. Ten subjects underwent imaging with adaptive optics scanning light ophthalmoscopy (AOSLO), and cone density was measured. Results. We found mutations in 22 of 25 subjects, including five novel mutations. All subjects lacked complete excavation of inner retinal layers at the fovea, though four subjects had foveal pits with normal diameter and/or volume. Peak cone density and OS lengthening were variable and overlapped with that observed in normal controls. A fifth hyper-reflective band was observed in the outer retina on SD-OCT in the majority of the subjects with albinism. Conclusions. Foveal cone specialization and pit morphology vary greatly in albinism. Normal cone packing was observed in the absence of a foveal pit, suggesting a pit is not required for packing to occur. The degree to which retinal anatomy correlates with genotype or visual function remains unclear, and future examination of larger patient groups will provide important insight on this issue