6,441 research outputs found
A Poisson structure on compact symmetric spaces
We present some basic results on a natural Poisson structure on any compact
symmetric space. The symplectic leaves of this structure are related to the
orbits of the corresponding real semisimple group on the complex flag manifold.Comment: 11 pages, exposition streamline
Neutral genetic drift can aid functional protein evolution
BACKGROUND: Many of the mutations accumulated by naturally evolving proteins
are neutral in the sense that they do not significantly alter a protein's
ability to perform its primary biological function. However, new protein
functions evolve when selection begins to favor other, "promiscuous" functions
that are incidental to a protein's biological role. If mutations that are
neutral with respect to a protein's primary biological function cause
substantial changes in promiscuous functions, these mutations could enable
future functional evolution.
RESULTS: Here we investigate this possibility experimentally by examining how
cytochrome P450 enzymes that have evolved neutrally with respect to activity on
a single substrate have changed in their abilities to catalyze reactions on
five other substrates. We find that the enzymes have sometimes changed as much
as four-fold in the promiscuous activities. The changes in promiscuous
activities tend to increase with the number of mutations, and can be largely
rationalized in terms of the chemical structures of the substrates. The
activities on chemically similar substrates tend to change in a coordinated
fashion, potentially providing a route for systematically predicting the change
in one function based on the measurement of several others.
CONCLUSIONS: Our work suggests that initially neutral genetic drift can lead
to substantial changes in protein functions that are not currently under
selection, in effect poising the proteins to more readily undergo functional
evolution should selection "ask new questions" in the future
Trademarked for Death? A Licensee\u27s Trademark Rights After an Executory Contract Is Rejected in Bankruptcy
In 1872, a young man named Claudio Alvarez Lefebre began manufacturing and selling high-quality rum in Cuba under the brand name Ron Matusalem. In 1948, as the family-run business prospered, the company registered a trademark and corporate logo in the United States. Upon his death, Lefebre left the business-and the secret formulas for making his rum-to his wife and children. By the early 1960s, Lefebre\u27s wife and children had immigrated to the United States, and they split the rum-making business into two separate corporations. These two distinct entities negotiated an executory contract in the form of a franchise agreement with a trademark license . This agreement granted the franchisee corporation the right to sell Ron Matusalem rums worldwide under the Ron Matusalem trademark. The franchisor corporation retained the right to control the nature and quality of the rums sold and the right to terminate the agreement if the franchisee failed to meet its standards. For the next two decades, the two corporations operated as a cohesive family business, or, as a court described them, a loose knit strada of corporations.
... Part II of this Note examines relevant sections of 11 U.S.C. 365, subsequent amendments under the Intellectual Property Licenses in Bankruptcy Act ( IPLBA ), and theoretical interpretations and definitions of what rejection means within the context of bankruptcy law.
Part III analyzes the circuit split, discussing the merits and weaknesses of each approach. Part IV suggests that the Supreme Court resolve the circuit split by adopting a modified version of the Seventh and Third Circuits\u27 approach, but adding the requirement that trademark licensees maintain the quality control standards initially contained in the parties\u27 original licensing agreement
Learning from Multi-View Multi-Way Data via Structural Factorization Machines
Real-world relations among entities can often be observed and determined by
different perspectives/views. For example, the decision made by a user on
whether to adopt an item relies on multiple aspects such as the contextual
information of the decision, the item's attributes, the user's profile and the
reviews given by other users. Different views may exhibit multi-way
interactions among entities and provide complementary information. In this
paper, we introduce a multi-tensor-based approach that can preserve the
underlying structure of multi-view data in a generic predictive model.
Specifically, we propose structural factorization machines (SFMs) that learn
the common latent spaces shared by multi-view tensors and automatically adjust
the importance of each view in the predictive model. Furthermore, the
complexity of SFMs is linear in the number of parameters, which make SFMs
suitable to large-scale problems. Extensive experiments on real-world datasets
demonstrate that the proposed SFMs outperform several state-of-the-art methods
in terms of prediction accuracy and computational cost.Comment: 10 page
Online Unsupervised Multi-view Feature Selection
In the era of big data, it is becoming common to have data with multiple
modalities or coming from multiple sources, known as "multi-view data".
Multi-view data are usually unlabeled and come from high-dimensional spaces
(such as language vocabularies), unsupervised multi-view feature selection is
crucial to many applications. However, it is nontrivial due to the following
challenges. First, there are too many instances or the feature dimensionality
is too large. Thus, the data may not fit in memory. How to select useful
features with limited memory space? Second, how to select features from
streaming data and handles the concept drift? Third, how to leverage the
consistent and complementary information from different views to improve the
feature selection in the situation when the data are too big or come in as
streams? To the best of our knowledge, none of the previous works can solve all
the challenges simultaneously. In this paper, we propose an Online unsupervised
Multi-View Feature Selection, OMVFS, which deals with large-scale/streaming
multi-view data in an online fashion. OMVFS embeds unsupervised feature
selection into a clustering algorithm via NMF with sparse learning. It further
incorporates the graph regularization to preserve the local structure
information and help select discriminative features. Instead of storing all the
historical data, OMVFS processes the multi-view data chunk by chunk and
aggregates all the necessary information into several small matrices. By using
the buffering technique, the proposed OMVFS can reduce the computational and
storage cost while taking advantage of the structure information. Furthermore,
OMVFS can capture the concept drifts in the data streams. Extensive experiments
on four real-world datasets show the effectiveness and efficiency of the
proposed OMVFS method. More importantly, OMVFS is about 100 times faster than
the off-line methods
Geometric validation of a computer simulator used in radiography education
The radiographical process of projection of a complex human form onto a two-dimensional image plane gives rise to distortions and magnifications. It is important that any simulation used for educational purposes should correctly reproduce these. Images generated using a commercially available computer simulation widely used in radiography education (ProjectionVRTM) were tested for geometric accuracy of projection in all planes.Methods:An anthropomorphic skull phantom was imaged using standard projection radiography techniques and also scanned using axial CT acquisition. The data from the CT was then loaded into the simulator and the same projection radiography techniques simulated. Bony points were identified on both the real radiographs and the digitally reconstructed radiographs (DRRs). Measurements sensitive to rotation and magnification were chosen to check for rotation and distortion errors.Results:The real radiographs and the DRRs were compared by four experienced observers and measurements taken between the identified bony points on each of the images obtained. Analysis of the mean observations shows that the measurement from the DRR matches the real radiograph +1.5 mm/−1.5 mm. The Bland Altman bias was 0.55 (1.26 STD), with 95% limits of agreement 3.01 to −1.91.Conclusions:Agreement between the empirical measurements is within the reported error of cephalometric analysis in all three anatomical planes. The image appearances of both the real radiographs and DRRs compared favourably.Advances in knowledge:The commercial computer simulator under test (ProjectionVRTM) was able to faithfully recreate the image appearances of real radiography techniques, including magnification and distortion. Students using this simulation for training will obtain feedback likely to be useful when lessons are applied to real-world situations
Multi-view Graph Embedding with Hub Detection for Brain Network Analysis
Multi-view graph embedding has become a widely studied problem in the area of
graph learning. Most of the existing works on multi-view graph embedding aim to
find a shared common node embedding across all the views of the graph by
combining the different views in a specific way. Hub detection, as another
essential topic in graph mining has also drawn extensive attentions in recent
years, especially in the context of brain network analysis. Both the graph
embedding and hub detection relate to the node clustering structure of graphs.
The multi-view graph embedding usually implies the node clustering structure of
the graph based on the multiple views, while the hubs are the boundary-spanning
nodes across different node clusters in the graph and thus may potentially
influence the clustering structure of the graph. However, none of the existing
works in multi-view graph embedding considered the hubs when learning the
multi-view embeddings. In this paper, we propose to incorporate the hub
detection task into the multi-view graph embedding framework so that the two
tasks could benefit each other. Specifically, we propose an auto-weighted
framework of Multi-view Graph Embedding with Hub Detection (MVGE-HD) for brain
network analysis. The MVGE-HD framework learns a unified graph embedding across
all the views while reducing the potential influence of the hubs on blurring
the boundaries between node clusters in the graph, thus leading to a clear and
discriminative node clustering structure for the graph. We apply MVGE-HD on two
real multi-view brain network datasets (i.e., HIV and Bipolar). The
experimental results demonstrate the superior performance of the proposed
framework in brain network analysis for clinical investigation and application
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