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Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Rooted trees, Hopf algebras and rough paths
有根树 Hopf代数 粗路径
2023/11/14
In this talk, we first recall some classical Hopf algebras on rooted trees, including Connes-Kreimer Hopf algebra and Loday-Ronco Hopf algebra. Then we give a combinatorial description of the coproduc...
Chasing carbon from trees to soils（图）
树木 土壤 碳追踪
2022/8/8
“Tuck your pants into your socks – the ticks can be really bad out here,” graduate student Dave Frey tells the group of four students as they embark from their cars.
Biologists analyzed data from 2,600 lizard species worldwide and discovered that, while hundreds of different types of lizards have independently evolved arboreal lifestyles, species that possessed st...
New way to identify disease-resistant genes in chocolate-producing trees（图）
New way disease-resistant genes chocolate-producing trees
2019/12/11
Chocolate-producing cacao trees that are resistant to a major pathogen were identified by an international team of plant geneticists. The NSF-funded finding points the way for plant breeders to develo...
Striped maple trees often change mating types, with females more likely to die（图）
Striped maple trees change mating types females likely to die
2019/6/6
More than 90 percent of flowering plant species combine male and female characteristics in one plant. In the less than 10 percent where female and male flowers exist on separate plants, they typically...
Researchers invent a breakthrough process to produce renewable car tires from trees and grasses
Researchers breakthrough process produce renewable car trees grasses
2017/2/8
A team of researchers, led by the University of Minnesota, has invented a new technology to produce automobile tires from trees and grasses in a process that could shift the tire production industry t...
SEMI-AUTOMATED APPROACH FOR MAPPING URBAN TREES FROM INTEGRATED AERIAL LiDAR POINT CLOUD AND DIGITAL IMAGERY DATASETS
Extraction Integrated Airborne LiDAR Multispectral Image Urban Trees
2016/9/29
Mapping of trees plays an important role in modern urban spatial data management, as many benefits and applications inherit from this detailed up-to-date data sources. Timely and accurate acquisition ...
Drought left 225 million trees dead in the U.S. Southwest in 2002. Nine years later, it killed 300 million trees in Texas. This past year, 12 million trees died in California.Drought left 225 million ...
Study:Alaskan boreal forest fires release more carbon than the trees can absorb
Alaskan boreal forest fires carbon trees
2015/10/19
A new analysis of fire activity in Alaska's Yukon Flats finds that so many forest fires are occurring there that the area has become a net exporter of carbon to the atmosphere. This is worrisome, the ...
Bartholdi, Neuhauser and Woess proved that a family of metabelian groups including lamplighters have a striking geometric manifestation as 1-skeleta of horocyclic products of trees. The purpose of thi...
The absence of efficient dual pairs of spanning trees in planar graphs
planar graphs cells
2015/8/26
A spanning tree T in a finite planar connected graph G determines a dual spanning tree T* in the dual graph G* such that T and T* do not intersect. We show that it is not always possible to find T in ...
Groups of automorphisms of trees and their limit sets
Groups automorphisms trees limit sets
2015/8/26
Let T be a locally finite simplicial tree and let ! ⊂ Aut(T ) be a finitely generated discrete subgroup. We obtain an explicit formula for the critical exponent of the Poincare series associated...
Shrinking Trees
Shrinking Trees
2015/8/21
Tree-based models provide an alternative to linear models for classification and regression data. They are used primarily for exploratory analysis of complex data or as a diagnostic tool following a l...
Variation in demersal fish species richness in the oceans surrounding New Zealand:an analysis using boosted regression trees
Demersal fish Species richness Boosted regression trees Statistical model
2015/8/21
We analysed relationships between demersal fish species richness, environment and trawl characteristics using an extensive collection of trawl data from the oceans around New Zealand. Analyses were ca...
Margin trees for high-dimensional classification
Maximum margin classifier supprt vector machine decision tree CART
2015/8/21
We propose a method for the classification of more than two classes, from high-dimensional features. Our approach is to build a binary decision tree in a top-down manner, using the optimal margin clas...