Co-evolution of Selection and Influence in Social Networks

Many networks are complex dynamical systems, where both attributes of nodes and topology of the network (link structure) can change with time. We propose a model of co-evolving networks where both node at- tributes and network structure evolve under mutual influence. Specifically, we consider a mixed membership stochastic blockmodel, where the probability of observing a link between two nodes depends on their current membership vectors, while those membership vectors themselves evolve in the presence of a link between the nodes. Thus, the network is shaped by the interaction of stochastic processes describing the nodes, while the processes themselves are influenced by the changing network structure. We derive an efficient variational inference procedure for our model, and validate the model on both synthetic and real-world data.Comment: In Proc. of the Twenty-Fifth Conference on Artificial Intelligence (AAAI-11

Synthesis and Properties of Two Dimensional Doped Transition Metal Dichalcogenides

Since graphene was discovered in 2004, two-dimensional (2D) materials have been actively studied. Especially, 2D transition metal dichalcogenides (TMDs), such as MoS2 and WS2, have been the subject of significant research because of their exceptional optical, electrical, magnetic, catalytic, and morphological properties. Therefore, these materials are expected to be used in a variety of applications. Furthermore, tuning the properties of TMDs is essential to improve their performance and expand their applications. This review classifies the various doping methods of 2D TMDs, and it summarizes how the dopants interact with the materials and how the performance of the materials improves depending on the synthesis methods and the species of the dopants

Latent Self-Exciting Point Process Model for Spatial-Temporal Networks

We propose a latent self-exciting point process model that describes geographically distributed interactions between pairs of entities. In contrast to most existing approaches that assume fully observable interactions, here we consider a scenario where certain interaction events lack information about participants. Instead, this information needs to be inferred from the available observations. We develop an efficient approximate algorithm based on variational expectation-maximization to infer unknown participants in an event given the location and the time of the event. We validate the model on synthetic as well as real-world data, and obtain very promising results on the identity-inference task. We also use our model to predict the timing and participants of future events, and demonstrate that it compares favorably with baseline approaches.Comment: 20 pages, 6 figures (v3); 11 pages, 6 figures (v2); previous version appeared in the 9th Bayesian Modeling Applications Workshop, UAI'1

The Effect of Herbal Diet on Skeletal Muscle Mass After Resistance Training in Rats

Resistance training has been well established as an effective strategy for muscle hypertrophy, increase in skeletal muscle mass and strength. Herbal diet has been introduced as an alternative treatment to alleviate muscle atrophy and therapeutic intervention. However, there is little evidence on the effect of herbal diet on skeletal muscle mass. To investigate whether herbal diet affects skeletal muscle mass after resistance training in rats. Twenty-four rats were randomly divided into 3 groups: 1) Control (CON, N=8), 2) Resistance training (RT, N=8), 3) RT+Herb (RTH, N=8). Resistance training was performed every other day for 8 weeks using ladder climbing. The ladder climbing exercise consisted of 3 sets of 5 repetitions with a 1 min rest interval between the repetitions and a 2 min rest between the sets. Huang Qi (Radix Astragali Membranceus) was given via oral gavage once a day for 8 weeks (1 ml mixed with water based on concentration of 368 mg/kg). All rats received sham treatment, same as treatment groups. All data were analyzed using One-way ANOVA. After 8 weeks of interventions, muscle mass of Gastrocnemius, Plantaris, and Flexor hallucis longus showed significant increases in RT and RTH groups compared to CON (

Dedicated preparation for in situ transmission electron microscope tensile testing of exfoliated graphene

Graphene, which is one of the most promising materials for its state-of-the-art applications, has received extensive attention because of its superior mechanical properties. However, there is little experimental evidence related to the mechanical properties of graphene at the atomic level because of the challenges associated with transferring atomically-thin two-dimensional (2D) materials onto microelectromechanical systems (MEMS) devices. In this study, we show successful dry transfer with a gel material of a stable, clean, and free-standing exfoliated graphene film onto a push-to-pull (PTP) device, which is a MEMS device used for uniaxial tensile testing in in situ transmission electron microscopy (TEM). Through the results of optical microscopy, Raman spectroscopy, and TEM, we demonstrate high quality exfoliated graphene on the PTP device. Finally, the stress???strain results corresponding to propagating cracks in folded graphene were simultaneously obtained during the tensile tests in TEM. The zigzag and armchair edges of graphene confirmed that the fracture occurred in association with the hexagonal lattice structure of graphene while the tensile testing. In the wake of the results, we envision the dedicated preparation and in situ TEM tensile experiments advance the understanding of the relationship between the mechanical properties and structural characteristics of 2D materials

MOF-Derived Cu@Cu2O Nanocatalyst for Oxygen Reduction Reaction and Cycloaddition Reaction

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and rapid method involving the reduction of a copper(II)-containing MOF with sodium borohydride solution at room temperature. The obtained nanoparticles consist of a copper core and a copper oxide shell exhibited catalytic activity in the oxygen reduction reaction. The as-synthesized Cu@Cu2O core-shell nanocatalyst exhibited an enhanced limit current density as well as onset potential in the electrocatalytic oxygen reduction reaction (ORR). Moreover, the nanoparticles exhibited good catalytic activity in the Huisgen cycloaddition of various substituted azides and alkynes under mild reaction conditions

Where College Students Live Can Impact Their Eating and Exercise Habits

University freshmen usually face with huge environmental changes. They are often stressful and may lead to some health-related problems. We wanted to know whether or not their residence influences eating and exercising habits. PURPOSE: To examine the effect of residence on level of physical activity, eating and other health related habits in college students. Methods: Total 71 college students participated in this study. Thirty one lives on campus and forty lives off campus. Participants completed a consent form and measurements of body weight, height, and body mass index (BMI). Level of physical activity was monitored using pedometer for 7 days. Exercise, smoke, and drink habits were surveyed by questionnaire. Diet pattern was assessed by the researcher based on the daily log for 7 days using computer software. Results: Of the 71 participants, 31.0% were men and 69.0% were women. Students living on campus were 40.9% in men and 43.7% in women. Physical activity was significantly higher in students living on campus both in men (14,152 ± 1,120.2 vs. 7,611 ± 3,379, p\u3c.001) and women (13,043 ± 3,864 vs. 5,948 ± 1,803, p\u3c.001) than students living off campus. In women, the total calorie (1,776 ± 414.7 vs. 1,493 ± 419.5, p=.022), alcoholic drink (1.9±1.4 vs. 1.1±0.4, p=.016), and mono saturated fat intakes (15.1±6.7 vs. 10.5±5.4, p=.011) were significantly higher in students living on campus. Consumption of vitamin C, D, and E were significantly lower in women students living on campus than students living off campus. Conclusion: Students who live on campus have a higher level of physical activity compared to their off-campus counterparts in both gender. However, dietary pattern was affected by the residence of college students only in women. Especially in women, where college students live can be important factors to impact their physical activity, life habits, and dietary pattern. Physical activity and nutrition education are crucial for college students because their lifestyle and dietary pattern may predispose them to the development of various diseases

Revealing the Intrinsic Restructuring of Bi2O3 Nanoparticles into Bi Nanosheets during Electrochemical CO2 Reduction

Bismuth is a catalyst material that selectively produces formate during the electrochemical reduction of CO2. While different synthesis strategies have been employed to create electrocatalysts with better performance, the restructuring of bismuth precatalysts during the reaction has also been previously reported. The mechanism behind the change has, however, remained unclear. Here, we show that Bi2O3 nanoparticles supported on Vulcan carbon intrinsically transform into stellated nanosheet aggregates upon exposure to an electrolyte. Liquid cell transmission electron microscopy observations first revealed the gradual restructuring of the nanoparticles into nanosheets in the presence of 0.1 M KHCO3 without an applied potential. Our experiments also associated the restructuring with solubility of bismuth in the electrolyte. While the consequent agglomerates were stable under moderate negative potentials (−0.3 VRHE), they dissolved over time at larger negative potentials (−0.4 and −0.5 VRHE). Operando Raman spectra collected during the reaction showed that under an applied potential, the oxide particles reduced to metallic bismuth, thereby confirming the metal as the working phase for producing formate. These results inform us about the working morphology of these electrocatalysts and their formation and degradation mechanisms.B.Á.-B. is grateful to the MICINN Spanish Ministry for the predoctoral grant (reference CTQ2016-76231-C2-2-R). B.Á.-B., V.M., and J.S.-G. acknowledge financial support by the MICINN Spanish Ministry, (Project PID2019-108136RB-C32) and Generalitat Valenciana (Project PROMETEO/2020/063). F.Y. acknowledges funding from the Chinese Scholars Council, A.Y. from the Humboldt Foundation (Germany), and M.L.L from the National Council of Science and Technology of Mexico (CONACyT, Grant No. 708585)

Air-stable van der Waals PtTe2 conductors with high current-carrying capacity and strong spin- orbit interaction

High-performance van der Waals (vdW) integrated electronics and spintronics require reliable current-carrying capacity. However, it is challenging to achieve high current density and air-stable performance using vdW metals owing to the fast electrical breakdown triggered by defects or oxidation. Here, we report that spin-orbit interacted synthetic PtTe2 layers exhibit significant electrical reliability and robustness in ambient air. The 4-nm-thick PtTe2 synthesized at a low temperature (similar to 400 degrees C) shows intrinsic metallic transport behavior and a weak antilocalization effect attributed to the strong spin-orbit scattering. Remarkably, PtTe2 sustains a high current density approaching approximate to 31.5 MA cm(-2), which is the highest value among electrical interconnect candidates under oxygen exposure. Electrical failure is caused by the Joule heating of PtTe2 rather than defect-induced electromigration, which was achievable by the native TeOx passivation. The high-quality growth of PtTe2 and the investigation of its transport behaviors lay out essential foundations for the development of emerging vdW spin-orbitronics