51 research outputs found
A Bayesian Nonparametric Approach to Modeling Motion Patterns
The most difficult—and often most essential—
aspect of many interception and tracking tasks is constructing
motion models of the targets to be found. Experts can
often provide only partial information, and fitting parameters
for complex motion patterns can require large amounts
of training data. Specifying how to parameterize complex
motion patterns is in itself a difficult task.
In contrast, nonparametric models are very flexible and
generalize well with relatively little training data. We propose
modeling target motion patterns as a mixture of Gaussian
processes (GP) with a Dirichlet process (DP) prior over
mixture weights. The GP provides a flexible representation
for each individual motion pattern, while the DP assigns observed
trajectories to particular motion patterns. Both automatically
adjust the complexity of the motion model based
on the available data. Our approach outperforms several parametric
models on a helicopter-based car-tracking task on
data collected from the greater Boston area
Regioselective Synthesis of Benzimidazolones via Cascade C–N Coupling of Monosubstituted Ureas
A direct method for the regioselective construction of benzimidazolones is reported wherein a single palladium catalyst is employed to couple monosubstituted urea substrates with differentially substituted 1,2-dihaloaromatic systems. In this method, the catalyst is able to promote a cascade of two discrete chemoselective C–N bond-forming processes that allows the highly selective and predictable formation of complex heterocycles from simple, readily available starting materials.National Institutes of Health (U.S.) (Award GM58160)National Institutes of Health (U.S.) (Award GM099817)Lanxess CorporationMassachusetts Institute of Technology. Undergraduate Research Opportunities Progra
Multi-ancestry genome-wide association meta-analysis of Parkinson?s disease
Although over 90 independent risk variants have been identified for Parkinson’s disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinson’s disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations
Defining the causes of sporadic Parkinson's disease in the global Parkinson's genetics program (GP2)
The Global Parkinson’s Genetics Program (GP2) will genotype over 150,000 participants from around the world, and integrate genetic and clinical data for use in large-scale analyses to dramatically expand our understanding of the genetic architecture of PD. This report details the workflow for cohort integration into the complex arm of GP2, and together with our outline of the monogenic hub in a companion paper, provides a generalizable blueprint for establishing large scale collaborative research consortia
Cation Radical Accelerated Nucleophilic Aromatic Substitution via Organic Photoredox Catalysis
Nucleophilic aromatic substitution
(S<sub>N</sub>Ar) is a direct
method for arene functionalization; however, it can be hampered by
low reactivity of arene substrates and their availability. Herein
we describe a cation radical-accelerated nucleophilic aromatic substitution
using methoxy- and benzyloxy-groups as nucleofuges. In particular,
lignin-derived aromatics containing guaiacol and veratrole motifs
were competent substrates for functionalization. We also demonstrate
an example of site-selective substitutive oxygenation with trifluoroethanol
to afford the desired trifluoromethylaryl ether
Spin-Forbidden Excitation Enables Infrared Photoredox Catalysis
We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation
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