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Sampling Arborescences in Parallel [article]

Nima Anari and Nathan Hu and Amin Saberi and Aaron Schild
2020 arXiv   pre-print
We show that sampling arborescences can be done in RNC.  ...  However, the classic reduction from sampling to counting seems to be inherently sequential. This raises the question of designing efficient parallel algorithms for sampling.  ...  We resolve the question of sampling arborescences in weighted directed graphs, and as a special case spanning trees in weighted undirected graphs, using efficient parallel algorithms with access to randomness  ... 
arXiv:2012.09502v1 fatcat:p3e54gol4jbblkhol3bc3vpm4y

ABRUPT DECELERATION OF MOLECULAR EVOLUTION LINKED TO THE ORIGIN OF ARBORESCENCE IN FERNS

Petra Korall, Eric Schuettpelz, Kathleen M. Pryer
2010 Evolution  
Here, we find a deceleration of molecular evolutionary rate to be coupled with the origin of arborescence in ferns.  ...  Although a similar pattern has been uncovered in flowering plants, using proxies such as growth form, the underlying process has remained elusive.  ...  Note that the slope in this figure is largely sampling dependent, with the sparser sampling outside of tree ferns resulting in steeper slopes than the denser sampling within tree ferns; absolute rate changes  ... 
doi:10.1111/j.1558-5646.2010.01000.x pmid:20394660 fatcat:p6czhfws5vhedm2covwooyfipm

Mechanical Structure of the Stem of Arborescent Palms

Paul M. Rich
1987 Botanical Gazette  
This difference between palm stem tissue and common woods may result from differences in cell structure and cell wall chemical composition.  ...  Young palms are overbuilt with respect to diameter and older palms are underbuilt, compared with arborescent dicotyledons and conifers.  ...  The distribution of stiffness and strength in palm stems parallels the distribution of dry density.  ... 
doi:10.1086/337626 fatcat:st6t2fvxfzax5a7i75ojbjsopm

Using geoestatistics for assessing biodiversity of forest reserve areas

Débora Andréia Neves, Fábio Lemos, Antonio Paz González, Sidney Rosa Vieira, Glécio Machado Siqueira
2010 Bragantia  
Cross-semivariograms could also be computed and modelled in some cases.  ...  Biodiversity as measured by species and number of individuals was assessed in two forest reserve zones located within reforestations of Eucalyptus sp and Pinus sp in Agudos, São Paulo, Brazil.  ...  Sample size was 1 m 2 and 100 m 2 for herbaceous and arborescent vegetation height classes, respectively. Results are shown in Table 3 .  ... 
doi:10.1590/s0006-87052010000500014 fatcat:tzgwerzkrbffznfnmjvc4ihyte

Prime Factorization of the Kirchhoff Polynomial: Compact Enumeration of Arborescences [article]

Matúš Mihalák, Przemysław Uznański, Pencho Yordanov
2015 arXiv   pre-print
,e_n-1 can be represented as a monomial e_1· e_2 ... e_n-1 in variables e ∈ E. All arborescences arb(G) of a digraph then define the Kirchhoff polynomial ∑_A ∈arb(G)∏_e∈ A e.  ...  We study the problem of enumerating all rooted directed spanning trees (arborescences) of a directed graph (digraph) G=(V,E) of n vertices. An arborescence A consisting of edges e_1,...  ...  Random sampling.  ... 
arXiv:1507.07727v1 fatcat:f2dqcbh4qbbppb67apd6bo5b5a

Prime Factorization of the Kirchhoff Polynomial: Compact Enumeration of Arborescences

Matúš Mihalák, Przemysław Uznański, Pencho Yordanov
2015 2016 Proceedings of the Thirteenth Workshop on Analytic Algorithmics and Combinatorics (ANALCO)  
An arborescence A consisting of edges e1, . . . , en−1 can be represented as a monomial e1 · e2 · · · en−1 in variables e ∈ E.  ...  All arborescences arb(G) of a digraph then define the Kirchhoff polynomial A∈arb(G) e∈A e.  ...  Random sampling.  ... 
doi:10.1137/1.9781611974324.10 dblp:conf/analco/MihalakUY16 fatcat:peqxqp2vxzd2dccfzdzue54ubi

Page 79 of American Journal of Science Vol. 20, Issue 58 [page]

1855 American Journal of Science  
—The occurrence of this metal and its associates with the gold of Port Orford, has been previously noticed in this Jour- nal.* It appears to constitute a large percentage of some of the samples of gold  ...  Blake on the Gold Region of California and Oregon. 79 I have a very beautiful specimen of this character in the form of a leaf: one side is beautifully arborescent, and the other is studded with perfect  ... 

Lattice Boltzmann method for shape optimization of fluid distributor

Limin Wang, Yilin Fan, Lingai Luo
2014 Computers & Fluids  
This paper presents the shape optimization of a flat-type arborescent fluid distributor for the purpose of process intensification.  ...  fluid distributor, and suggesting the interests of the proposed optimization algorithm in engineering optimal design.  ...  Numerical experiments are also carried out in parallel for comparing flow distribution and hydrodynamic characteristics of the distributors.  ... 
doi:10.1016/j.compfluid.2014.01.034 fatcat:4ons6vbdibfg5ei6ht37tnooq4

Implications of non-uniqueness in phylogenetic deconvolution of bulk DNA samples of tumors

Yuanyuan Qi, Dikshant Pradhan, Mohammed El-Kebir
2019 Algorithms for Molecular Biology  
In addition, we study the sampling performance of current methods, identifying significant biases.  ...  This work provides the theoretical foundations for non-uniqueness of solutions in tumor phylogeny inference from bulk DNA samples.  ...  In Fig. 2, the number of spanning arborescences in G F is deg in (2) · deg in (3) · deg in (4) · deg in (5) = 1 · 2 · 1 · 3 = 6 .  ... 
doi:10.1186/s13015-019-0155-6 pmid:31497065 pmcid:PMC6719395 fatcat:pffelzndqjchnbkjo7d2gcdqhu

Speleothems in quartz-sandstone caves of Ponta Grossa municipality, Campos Gerais region, Paraná state, southern Brazil

Henrique Pontes, Ponta Grossa State University (UEPG) and University Group of Speleological Research (GUPE), Luiz Fernandes, Mário de Melo, Gilson Guimarães, Laís Massuqueto, Federal University of Paraná (UFPR), Ponta Grossa State University (UEPG), Ponta Grossa State University (UEPG) and University Group of Speleological Research (GUPE), Federal University of Paraná (UFPR) and University Group of Speleological Research (GUPE)
2020 International Journal of Speleology  
) quartz-sandstones, in southern Brazil.  ...  The speleothems were classified into six types based on form, composition and genesis: (1) arborescent (coral), (2) mushroom-shaped, (3) stalactitic, (4) stalagmitic, (5) columnar with horizontal/ascending  ...  Fig. 10 . 10 a) Arborescent speleothem and thin section photomicrography under parallel polarizers showing the subdivisions of the speleothem, b) inner microfacies, c) intermediate microfacies, and d)  ... 
doi:10.5038/1827-806x.49.2.2313 fatcat:cc5cxjm7vvap3b7c2ddut6dpyy

Effects of Prescribed Fire on the Buried Seed Bank in Mixed-Hardwood Forests of the Southern Appalachian Mountains

Tara L. Keyser, Tracy Roof, Jacquelyne L. Adams, Dean Simon, Gordon Warburton
2012 Southeastern naturalist (Steuben, Me.)  
No differences in total seed-bank density, Shannon-Weiner's diversity index (H′) , or overall species composition between pre-and post-fire sampling or between the LD and MS layers were observed.  ...  Similarity, as defined by Sørenson's index, of species common to the seed bank and aboveground forest understory was low, with a slight increase in Sørenson's index observed during post-fire sampling of  ...  In addition, the authors thank Kenny Frick for assistance in collecting seed-bank samples as well as assisting on the prescribed burn; Alisha Goodman and Andrea Hinek for assistance in sample collection  ... 
doi:10.1656/058.011.0407 fatcat:alvk2hug2neerdz7vlxiu5l6qm

Woody Anatomy of Platyopuntias

Arthur Gibson
1978 Aliso  
In diffuse-porous stem woods, the widest vessels occur in arborescent species, and mean vessel diameters roughly decrease with a decrease in plant height and erectness, thus paralleling trends in vessel-element  ...  Elimination of vascular tracheids in secondary xylem is paralleled by their elimination in primary xylem and ground tissue.  ... 
doi:10.5642/aliso.19780902.08 fatcat:5rsybmr66bfy7knz7b45es4ery

Depositional cyclicity and paleoecological variability in an outcrop of Rio Bonito formation, Early Permian, Paraná Basin, Rio Grande do Sul, Brazil

André Jasper, Rualdo Menegat, Margot Guerra-Sommer, Miriam Cazzulo-Klepzig, Paulo Alves de Souza
2006 Journal of South American Earth Sciences  
The palynoflora identified in the basal section present a dominance of spores produced by arborescent and herbaceous lycophytes, as well as by sphenophytes and filicophytes, complementary forms of gymnosperm  ...  The basal section of this outcrop represents a coastal lagoon depositional system protected by barriers in microtide conditions, where peat-forming conditions developed in lowlands with ingression of distal  ...  The relative abundance takes into consideration the following rates: rare forms 1-3 fragments per sample, common forms 4-7 fragments per sample, and abundant forms more than 7 fragments per sample.  ... 
doi:10.1016/j.jsames.2006.05.002 fatcat:wscnkfkt2vhvxnyeihvxuuquu4

Expedient Metrics to Describe Plant Community Change Across Gradients of Anthropogenic Influence

José A. P. Marcelino, Everett Weber, Luís Silva, Patrícia V. Garcia, António O. Soares
2014 Environmental Management  
The percentage match with reference community types ranged from 77 to 100 % and from 79 to 100 %, for herbaceous and arborescent vegetation plots, respectively.  ...  Our goal was to identify plant indicator species across two gradients of increasing anthropogenic influence and management (arborescent and herbaceous communities) and determine similarity between plant  ...  Two replicates of the 8 habitat communities (4 herbaceous and 4 arborescent) were sampled for each island.  ... 
doi:10.1007/s00267-014-0321-z pmid:25047274 fatcat:ryoafmntrratnowmb363gda7na

An arborescent lycopsid stem fragment from the Palliser Formation (Famennian) carbonate platform, southwestern Alberta, Canada, and its paleogeographic and paleoclimatic significance

Brian R. Pratt, Johan van Heerde
2017 Canadian journal of earth sciences (Print)  
Lower Costigan Member, Palliser Formation, Jura Creek (float sample). B.  ...  Here we document an unusual occurrence of a fossil arborescent lycopsid preserved as a silicified stem fragment in tidal flat dolomite of a Famennian-aged carbonate platform.  ... 
doi:10.1139/cjes-2016-0117 fatcat:4lnjzqyckfbvln662ktzt7t5cm
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