4,615 research outputs found
Social Influence and the Collective Dynamics of Opinion Formation
Social influence is the process by which individuals adapt their opinion,
revise their beliefs, or change their behavior as a result of social
interactions with other people. In our strongly interconnected society, social
influence plays a prominent role in many self-organized phenomena such as
herding in cultural markets, the spread of ideas and innovations, and the
amplification of fears during epidemics. Yet, the mechanisms of opinion
formation remain poorly understood, and existing physics-based models lack
systematic empirical validation. Here, we report two controlled experiments
showing how participants answering factual questions revise their initial
judgments after being exposed to the opinion and confidence level of others.
Based on the observation of 59 experimental subjects exposed to peer-opinion
for 15 different items, we draw an influence map that describes the strength of
peer influence during interactions. A simple process model derived from our
observations demonstrates how opinions in a group of interacting people can
converge or split over repeated interactions. In particular, we identify two
major attractors of opinion: (i) the expert effect, induced by the presence of
a highly confident individual in the group, and (ii) the majority effect,
caused by the presence of a critical mass of laypeople sharing similar
opinions. Additional simulations reveal the existence of a tipping point at
which one attractor will dominate over the other, driving collective opinion in
a given direction. These findings have implications for understanding the
mechanisms of public opinion formation and managing conflicting situations in
which self-confident and better informed minorities challenge the views of a
large uninformed majority.Comment: Published Nov 05, 2013. Open access at:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.007843
Topological phases and phase transitions on the square-octagon lattice
We theoretically investigate a tight binding model of fermions hopping on the
square-octagon lattice which consists of a square lattice with plaquette
corners themselves decorated by squares. Upon the inclusion of second neighbor
spin-orbit coupling or non-Abelian gauge fields, time-reversal symmetric
topological Z_2 band insulators are realized. Additional insulating and gapless
phases are also realized via the non-Abelian gauge fields. Some of the phase
transitions involve topological changes to the Fermi surface. The stability of
the topological phases to various symmetry breaking terms is investigated via
the entanglement spectrum. Our results enlarge the number of known exactly
solvable models of Z_2 band insulators, and are potentially relevant to the
realization and identification of topological phases in both the solid state
and cold atomic gases.Comment: 12 pages, 9 figure
Three-Dimensional Bioprinting Materials with Potential Application in Preprosthetic Surgery
Current methods in handling maxillofacial defects are not robust and are highly dependent on the surgeon’s skills and the inherent potential in the patients’ bodies for regenerating lost tissues. Employing custom-designed 3D printed scaffolds that securely and effectively reconstruct the defects by using tissue engineering and regenerative medicine techniques can revolutionize preprosthetic surgeries. Various polymers, ceramics, natural and synthetic bioplastics, proteins, biomolecules, living cells, and growth factors as well as their hybrid structures can be used in 3D printing of scaffolds, which are still under development by scientists. These scaffolds not only are beneficial due to their patient-specific design, but also may be able to prevent micromobility, make tension free soft tissue closure, and improve vascularity. In this manuscript, a review of materials employed in 3D bioprinting including bioceramics, biopolymers, composites, and metals is conducted. A discussion of the relevance of 3D bioprinting using these materials for craniofacial interventions is included as well as their potential to create analogs to craniofacial tissues, their benefits, limitations, and their application
Influence of roasting, gamma ray irradiation and microwaving on ruminal dry matter and crude protein digestion of cottonseed
The aim of the current study was to compare the effect of different physical processing methods including roasting at 140 C for 15 (R15) or 30 minutes (R30), gamma ray irradiation (c-irradiation) at doses of 15 (c15), 30 (c30) and 45 (c45) kGy, and microwaving at 800 W for 2 (MW2), 4 (MW4) and 6 minutes (MW6) of whole cottonseed (WCS) on ruminal degradation. In vitro crude protein (CP) digestibility and gossypol contents were compared as well. In situ experiment was conducted on three permanent rumen-fistulated bulls. Gossypol content was decreased among treatments (p<0.05). The lowest degradation rate of protein in rumen was obtained for c45 treatment. The rate of degradation of the potentially degradation fraction was decreased for both dry matter (DM) (p¼0.002) and CP (p¼0.006) with different treatments. The lowest values for effective degradation in all passage rates were obtained with c45. Both microwaving and c irradiation showed difference for CP effective degradability parameter. The greatest value of in vitro CP digestibility (p<0.05) was observed for a dose of 45 kGy gamma-irradiated cottonseed compared to untreated WCS. Based on the results, c ray irradiation with 45 kGy was the most effective processing method in both reducing the gossypol content and escaping the protein through rumen for WCS in ruminant nutrition
A Current Overview of Materials and Strategies for Potential Use in Maxillofacial Tissue Regeneration
Tissue regeneration is rapidly evolving to treat anomalies in the entire human body. The production of biodegradable, customizable scaffolds to achieve this clinical aim is dependent on the interdisciplinary collaboration among clinicians, bioengineers and materials scientists. While bone grafts and varying reconstructive procedures have been traditionally used for maxillofacial defects, the goal of this review is to provide insight on all materials involved in the progressing utilization of the tissue engineering approach to yield successful treatment outcomes for both hard and soft tissues. In vitro and in vivo studies that have demonstrated the restoration of bone and cartilage tissue with different scaffold material types, stem cells and growth factors show promise in regenerative treatment interventions for maxillofacial defects. The repair of the temporomandibular joint (TMJ) disc and mandibular bone were discussed extensively in the report, supported by evidence of regeneration of the same tissue types in different medical capacities. Furthermore, in addition to the thorough explanation of polymeric, ceramic, and composite scaffolds, this review includes the application of biodegradable metallic scaffolds for regeneration of hard tissue. The purpose of compiling all the relevant information in this review is to lay the foundation for future investigation in materials used in scaffold synthesis in the realm of oral and maxillofacial surgery
Structure Space of Model Proteins --A Principle Component Analysis
We study the space of all compact structures on a two-dimensional square
lattice of size . Each structure is mapped onto a vector in
-dimensions according to a hydrophobic model. Previous work has shown that
the designabilities of structures are closely related to the distribution of
the structure vectors in the -dimensional space, with highly designable
structures predominantly found in low density regions. We use principal
component analysis to probe and characterize the distribution of structure
vectors, and find a non-uniform density with a single peak. Interestingly, the
principal axes of this peak are almost aligned with Fourier eigenvectors, and
the corresponding Fourier eigenvalues go to zero continuously at the
wave-number for alternating patterns (). These observations provide a
stepping stone for an analytic description of the distribution of structural
points, and open the possibility of estimating designabilities of realistic
structures by simply Fourier transforming the hydrophobicities of the
corresponding sequences.Comment: 14 pages, 12 figures, Conclusion has been modifie
Multi-Objective versus Single-Objective Models in Geodetic Network Optimization
Configuration of a network and observation weights plays an important role in designing and establishing a geodetic network. In this paper, we consider single- and multi-objective optimization models in some numerical investigation. The results illustrate that the reliability model yields the best results in view of internal and external reliability and achievable observation precision. This result we interpret as that the reliability criterion is more sensitive to the configuration of a network than any of the other criteria. We propose re-optimization of the network in the cases where very high (non-achievable) precision is required or when some conditions are not met in the optimization process
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