1,694 research outputs found
Two Photon Physics at LEP
LEP offers an excellent opportunity to measure two photon processes over a
large kinematical range and thus study the complex nature of the photon. This
article reviews the experimental status of ``Two Photon Physics'' at LEP. The
recent results on resonances, multi-hadron production and photon structure
functions are discussedComment: 14 pages, 18 figures, Talk given on behalf of LEP at PIC99, June
24-26 Ann Arbor, Michigan,US
Flexible and accurate inference and learning for deep generative models
We introduce a new approach to learning in hierarchical latent-variable
generative models called the "distributed distributional code Helmholtz
machine", which emphasises flexibility and accuracy in the inferential process.
In common with the original Helmholtz machine and later variational autoencoder
algorithms (but unlike adverserial methods) our approach learns an explicit
inference or "recognition" model to approximate the posterior distribution over
the latent variables. Unlike in these earlier methods, the posterior
representation is not limited to a narrow tractable parameterised form (nor is
it represented by samples). To train the generative and recognition models we
develop an extended wake-sleep algorithm inspired by the original Helmholtz
Machine. This makes it possible to learn hierarchical latent models with both
discrete and continuous variables, where an accurate posterior representation
is essential. We demonstrate that the new algorithm outperforms current
state-of-the-art methods on synthetic, natural image patch and the MNIST data
sets
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Structure-based selection of human metabolite binding P4 pocket of DRB1*15:01 and DRB1*15:03, with implications for multiple sclerosis.
Binding of small molecules in the human leukocyte antigen (HLA) peptide-binding groove may result in conformational changes of bound peptide and an altered immune response, but previous studies have not considered a potential role for endogenous metabolites. We performed virtual screening of the complete Human Metabolite Database (HMDB) for docking to the multiple sclerosis (MS) susceptible DRB1*15:01 allele and compared the results to the closely related yet non-susceptible DRB1*15:03 allele; and assessed the potential impact on binding of human myelin basic peptide (MBP). We observed higher energy scores for metabolite binding to DRB1*15:01 than DRB1*15:03. Structural comparison of docked metabolites with DRB1*15:01 and DRB1*15:03 complexed with MBP revealed that PhenylalanineMBP92 allows binding of metabolites in the P4 pocket of DRB1*15:01 but ValineMBP89 abrogates metabolite binding in the P1 pocket. We observed differences in the energy scores for binding of metabolites in the P4 pockets of DRB1*15:01 vs. DRB1*15:03 suggesting stronger binding to DRB1*15:01. Our study confirmed that specific, disease-associated human metabolites bind effectively with the most polymorphic P4 pocket of DRB1*15:01, the primary MS susceptible allele in most populations. Our results suggest that endogenous human metabolites bound in specific pockets of HLA may be immunomodulatory and implicated in autoimmune disease
Mosaic: Designing Online Creative Communities for Sharing Works-in-Progress
Online creative communities allow creators to share their work with a large
audience, maximizing opportunities to showcase their work and connect with fans
and peers. However, sharing in-progress work can be technically and socially
challenging in environments designed for sharing completed pieces. We propose
an online creative community where sharing process, rather than showcasing
outcomes, is the main method of sharing creative work. Based on this, we
present Mosaic---an online community where illustrators share work-in-progress
snapshots showing how an artwork was completed from start to finish. In an
online deployment and observational study, artists used Mosaic as a vehicle for
reflecting on how they can improve their own creative process, developed a
social norm of detailed feedback, and became less apprehensive of sharing early
versions of artwork. Through Mosaic, we argue that communities oriented around
sharing creative process can create a collaborative environment that is
beneficial for creative growth
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