10,678 research outputs found
Sandpile avalanche dynamics on scale-free networks
Avalanche dynamics is an indispensable feature of complex systems. Here we
study the self-organized critical dynamics of avalanches on scale-free networks
with degree exponent through the Bak-Tang-Wiesenfeld (BTW) sandpile
model. The threshold height of a node is set as with
, where is the degree of node . Using the branching
process approach, we obtain the avalanche size and the duration distribution of
sand toppling, which follow power-laws with exponents and ,
respectively. They are given as and
for , 3/2 and 2 for
, respectively. The power-law distributions are modified by a
logarithmic correction at .Comment: 8 pages, elsart styl
Analysis of telephone network traffic based on a complex user network
The traffic in telephone networks is analyzed in this paper. Unlike the
classical traffic analysis where call blockings are due to the limited channel
capacity, we consider here a more realistic cause for call blockings which is
due to the way in which users are networked in a real-life human society.
Furthermore, two kinds of user network, namely, the fully-connected user
network and the scale-free network, are employed to model the way in which
telephone users are connected. We show that the blocking probability is
generally higher in the case of the scale-free user network, and that the
carried traffic intensity is practically limited not only by the network
capacity but also by the property of the user network.Comment: 17 pages, 9 figures, accepted for Physica
Censored Sampling of Diffusion Models Using 3 Minutes of Human Feedback
Diffusion models have recently shown remarkable success in high-quality image
generation. Sometimes, however, a pre-trained diffusion model exhibits partial
misalignment in the sense that the model can generate good images, but it
sometimes outputs undesirable images. If so, we simply need to prevent the
generation of the bad images, and we call this task censoring. In this work, we
present censored generation with a pre-trained diffusion model using a reward
model trained on minimal human feedback. We show that censoring can be
accomplished with extreme human feedback efficiency and that labels generated
with a mere few minutes of human feedback are sufficient. Code available at:
https://github.com/tetrzim/diffusion-human-feedback.Comment: Published in NeurIPS 202
Nanodiamond-Gutta Percha Composite Biomaterials for Root Canal Therapy.
Root canal therapy (RCT) represents a standard of treatment that addresses infected pulp tissue in teeth and protects against future infection. RCT involves removing dental pulp comprising blood vessels and nerve tissue, decontaminating residually infected tissue through biomechanical instrumentation, and root canal obturation using a filler material to replace the space that was previously composed of dental pulp. Gutta percha (GP) is typically used as the filler material, as it is malleable, inert, and biocompatible. While filling the root canal space with GP is the standard of care for endodontic therapies, it has exhibited limitations including leakage, root canal reinfection, and poor mechanical properties. To address these challenges, clinicians have explored the use of alternative root filling materials other than GP. Among the classes of materials that are being explored as novel endodontic therapy platforms, nanodiamonds (NDs) may offer unique advantages due to their favorable properties, particularly for dental applications. These include versatile faceted surface chemistry, biocompatibility, and their role in improving mechanical properties, among others. This study developed a ND-embedded GP (NDGP) that was functionalized with amoxicillin, a broad-spectrum antibiotic commonly used for endodontic infection. Comprehensive materials characterization confirmed improved mechanical properties of NDGP over unmodified GP. In addition, digital radiography and microcomputed tomography imaging demonstrated that obturation of root canals with NDGP could be achieved using clinically relevant techniques. Furthermore, bacterial growth inhibition assays confirmed drug functionality of NDGP functionalized with amoxicillin. This study demonstrates a promising path toward NDGP implementation in future endodontic therapy for improved treatment outcomes
Lipidomic analyses, breast- and formula-feeding, and growth in infants.
OBJECTIVE: To evaluate lipidomic differences between breast- and formula-fed infants. STUDY DESIGN: We utilized high-resolution mass-spectrometry methods to analyze 3.2 mm dried blood spot samples collected at ages 3 months (n = 241) and 12 months (n = 144) from a representative birth cohort study. Lipidomic profiles were compared between infants exclusively breast-fed, formula-fed, or mixed-fed, and related to 12-month infancy weight. Data analysis included supervised multivariate statistics (partial least squares discriminant analysis), and univariate analysis with correction for multiple testing. RESULTS: Distinct differences in 3-month lipidomic profiles were observed between exclusively breast-fed and formula-fed infants; mixed-fed infants showed intermediate profiles. Principle lipidomic characteristics of breast-fed infants were lower total phosphatidylcholines (PCs), with specifically lower short chain unsaturated PC but higher long chain polyunsaturated PC; higher cholesterol esters; and variable differences in sphingomyelins. At 12 months, lipidomic profiles were markedly different to those at 3 months, and differences between the earlier breast/formula/mixed-feeding groups were no longer evident. However, several specific lipid species, associated with breast-feeding at 3 months, also correlated with differences in 3- to 12-month weight. CONCLUSIONS: State-of-the-art dried blood spot sample lipidomic profiling demonstrated striking differences between breast-fed and formula-fed infants. Although these changes diminished with age, breast-fed lipidomic profiles at 3 months were associated with infancy weight and could potentially represent biomarkers of infant nutrition.PP was supported by a UK MRC Clinical Training Fellowship (G1001995). The Cambridge Baby Growth Study has been supported by the European Union, the World Cancer Research Foundation International, the Medical Research Council (including a centenary award), and the NIHR Cambridge Comprehensive Biomedical Research Centre. The lipidomics assays were supported by the Medical Research Council (UD99999906 and Cambridge Lipidomics Biomarker Research Initiative G0800783).This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.jpeds.2014.10.02
An estimate of the QCD corrections to the decay Z --> W u d
We present an estimate of perturbative QCD corrections to the decay . A simple approximate approach is described in detail. The difference
of masses of and is used as an expansion parameter. A complete
analytical formula for a part of the corrections is also presented.Comment: 9 pages, late
Role of exchange interaction in self-consistent calculations of endohedral fullerenes
Results of the self-consistent calculation of electronic structure of
endohedral fullerene Ar@C within the Hartree-Fock and the local density
approximations are presented. Hartree-Fock approximation is used for the
self-consistent description for the first time. It is shown that the accurate
account of the exchange interaction between all electrons of the compound leads
to the significant modification of the atomic valent shell which causes the
noticeable charge redistribution inside the endohedral compound.Comment: 5 figures, Proceedings of the 5th Conference on Elementary Processes
in Atomic Systems (CEPAS 2011), submitted to Nuclear Instruments and Methods
in Physics Research Section
Evolution of scale-free random graphs: Potts model formulation
We study the bond percolation problem in random graphs of weighted
vertices, where each vertex has a prescribed weight and an edge can
connect vertices and with rate . The problem is solved by the
limit of the -state Potts model with inhomogeneous interactions for
all pairs of spins. We apply this approach to the static model having
so that the resulting graph is scale-free with
the degree exponent . The number of loops as well as the giant
cluster size and the mean cluster size are obtained in the thermodynamic limit
as a function of the edge density, and their associated critical exponents are
also obtained. Finite-size scaling behaviors are derived using the largest
cluster size in the critical regime, which is calculated from the cluster size
distribution, and checked against numerical simulation results. We find that
the process of forming the giant cluster is qualitatively different between the
cases of and . While for the former, the giant
cluster forms abruptly at the percolation transition, for the latter, however,
the formation of the giant cluster is gradual and the mean cluster size for
finite shows double peaks.Comment: 34 pages, 9 figures, elsart.cls, final version appeared in NP
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