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Computing Shrub-Depth Decompositions

Jakub Gajarský, Stephan Kreutzer, Markus Bläser, Christophe Paul
2020 Symposium on Theoretical Aspects of Computer Science  
We present an fpt algorithm for computing decompositions of graphs of bounded shrub-depth.  ...  To the best of our knowledge, this is the first algorithm which computes the decomposition directly, without use of rank-width decompositions and FO or MSO logic.  ...  S TA C S 2 0 2 0 56:14 Computing Shrub-Depth Decompositions The FPT-algorithm. We are now ready to present the fpt-algorithm for computing (d, m)tree-models.  ... 
doi:10.4230/lipics.stacs.2020.56 dblp:conf/stacs/GajarskyK20 fatcat:snp64kqn4zgwpannhk7xtidwyu

Snow–Shrub Interactions in Arctic Tundra: A Hypothesis with Climatic Implications

Matthew Sturm, Jon Holmgren, Joseph P. McFadden, Glen E. Liston, F. Stuart Chapin, Charles H. Racine
2001 Journal of Climate  
snow depth.  ...  As a consequence, winter soil surface temperatures are substantially higher, a condition that can promote greater winter decomposition and nutrient release, thereby providing a positive feedback that could  ...  to decomposition and nutrient mineralization.  ... 
doi:10.1175/1520-0442(2001)014<0336:ssiiat>2.0.co;2 fatcat:7lojosnm5vci5ntzwe6yubi6sa

Parameterized Algorithms for Modular-Width [chapter]

Jakub Gajarský, Michael Lampis, Sebastian Ordyniak
2013 Lecture Notes in Computer Science  
A class of graphs G has shrub-depth d if there exists m such that G ⊆ TM m (d), while for all natural m it is G ⊆ TM m (d − 1).  ...  manage to design FPT algorithms for Coloring and Partitioning into paths (and hence Hamiltonian path and Hamiltonian cycle), which are W-hard for both clique-width and its recently introduced restriction, shrub-depth  ...  Shrub-depth The recently introduced notion of shrub-depth [20] is the "low-depth" variant of clique-width, similar to the role that tree-depth plays with respect to treewidth. Definition 1.  ... 
doi:10.1007/978-3-319-03898-8_15 fatcat:h7jroriijbfwple2bschwuujfa

Parameterized Algorithms for Modular-Width [article]

Jakub Gajarský and Michael Lampis and Sebastian Ordyniak
2013 arXiv   pre-print
manage to design FPT algorithms for Coloring and Partitioning into paths (and hence Hamiltonian path and Hamiltonian cycle), which are W-hard for both clique-width and its recently introduced restriction, shrub-depth  ...  The main contribution of this paper is to consider a parameter called modular-width, defined using the well-known notion of modular decompositions.  ...  Shrub-depth The recently introduced notion of shrub-depth [20] is the "low-depth" variant of clique-width, similar to the role that tree-depth plays with respect to treewidth. Definition 1.  ... 
arXiv:1308.2858v2 fatcat:433mrukqlbhy3avakvjximj2gy

Shrub canopies influence soil temperatures but not nutrient dynamics: An experimental test of tundra snow-shrub interactions

Isla H. Myers-Smith, David S. Hik
2013 Ecology and Evolution  
Conversely, we found no strong evidence of increased soil decomposition, CO 2 fluxes, or nitrate or ammonia adsorbtion under artificial shrub canopy treatments when compared with unmanipulated open tundra  ...  The snow-shrub hypothesis asserts that shrub canopies trap snow and insulate soils in winter, increasing the rates of nutrient cycling to create a positive feedback to shrub expansion.  ...  We did, however, observe greater decomposition of paper at 5 cm depth in shrub plots (Fig. A2) .  ... 
doi:10.1002/ece3.710 pmid:24198933 pmcid:PMC3810868 fatcat:toalq3ruqrdw5kayzshxucs6li

Page 337 of Journal of Climate Vol. 14, Issue 3 [page]

2001 Journal of Climate  
We suggest that at these higher temperatures, more winter decomposition and nutrient mineralization may occur, producing more fa- vorable conditions for the growth of shrubs.  ...  | FEBRUARY 2001 -_— a) 2.00 Snow depth ® Canopy height Snow depth or Canopy height (m) Shrub tundra site (HV1) Tussock tundra site (HV2) m) Aelevation ( 200 300 400 500 600 700 800 900 1000 Distance (m  ... 

McGill Wetland Model: evaluation of a peatland carbon simulator developed for global assessments

F. St-Hilaire, J. Wu, N. T. Roulet, S. Frolking, P. M. Lafleur, E. R. Humphreys, V. Arora
2008 Biogeosciences Discussions  
Simulated moss NPP 15 approximates what would be expected for a bog peatland, but shrub NPP appears to be underestimated.  ...  5 description of autotrophic respiration was changed to be consistent with the formulation of photosynthesis; and 3. the cohort, multilayer soil respiration model was changed to a simple one box peat decomposition  ...  A greater sensitivity for shrubs than for mosses to water table depth seems to indicate that moss 10 PFT would be more stable than shrub PFT to changes in water table depth and thereby to changes in the  ... 
doi:10.5194/bgd-5-1689-2008 fatcat:plqwoh2pkbbh7nthzyb2pthoii

McGill wetland model: evaluation of a peatland carbon simulator developed for global assessments

F. St-Hilaire, J. Wu, N. T. Roulet, S. Frolking, P. M. Lafleur, E. R. Humphreys, V. Arora
2010 Biogeosciences  
Simulated moss NPP 15 approximates what would be expected for a bog peatland, but shrub NPP appears to be underestimated.  ...  5 description of autotrophic respiration was changed to be consistent with the formulation of photosynthesis; and 3. the cohort, multilayer soil respiration model was changed to a simple one box peat decomposition  ...  A greater sensitivity for shrubs than for mosses to water table depth seems to indicate that moss 10 PFT would be more stable than shrub PFT to changes in water table depth and thereby to changes in the  ... 
doi:10.5194/bg-7-3517-2010 fatcat:wzio27wdezhbreju5adcrcufci

Faster Deciding MSO Properties of Trees of Fixed Height, and Some Consequences

Jakub Gajarsky, Petr Hlineny, Marc Herbstritt
2012 Foundations of Software Technology and Theoretical Computer Science  
From that we obtain, by means of interpretation, corresponding results for the classes of graphs of bounded tree-depth (MSO 2 ) and shrub-depth (MSO 1 ), and thus we give wide generalizations of Lampis  ...  In the second part of the paper we use this kernel structure to show that FO has the same expressive power as MSO 1 on the graph classes of bounded shrub-depth.  ...  "nice connectivity properties" of a tree-depth decomposition.  ... 
doi:10.4230/lipics.fsttcs.2012.112 dblp:conf/fsttcs/GajarskyH12 fatcat:wit3in442fe4pn23tikkr6d54y

Towards a more detailed representation of high-latitude vegetation in the global land surface model ORCHIDEE (ORC-HL-VEGv1.0)

Arsène Druel, Philippe Peylin, Gerhard Krinner, Philippe Ciais, Nicolas Viovy, Anna Peregon, Vladislav Bastrikov, Natalya Kosykh, Nina Mironycheva-Tokareva
2017 Geoscientific Model Development Discussions  
Shrubs have a specific carbon allocation scheme, and differ from trees by their larger survival rates in winter, due to protection by snow.  ...  in the high latitudes, three new circumpolar Plant Functional Types (PFTs) were added in the ORCHIDEE land surface model, namely non-vascular plants (NVPs) representing bryophytes and lichens, arctic shrubs  ...  A PFT-dependent snow depth is needed to compute the protection of vegetation by snow (Sect. 2.3.3).  ... 
doi:10.5194/gmd-2017-65 fatcat:bgsp25ry3nbdno72fwdhkcsvqu

Towards a more detailed representation of high-latitude vegetation in the global land surface model ORCHIDEE (ORC-HL-VEGv1.0)

Arsène Druel, Philippe Peylin, Gerhard Krinner, Philippe Ciais, Nicolas Viovy, Anna Peregon, Vladislav Bastrikov, Natalya Kosykh, Nina Mironycheva-Tokareva
2017 Geoscientific Model Development  
Shrubs have a specific carbon allocation scheme, and differ from trees by their larger survival rates in winter, due to protection by snow.  ...  latitudes in the ORCHIDEE land surface model was improved by the addition of three new circumpolar plant functional types (PFTs), namely non-vascular plants representing bryophytes and lichens, Arctic shrubs  ...  A PFT-dependent snow depth is needed to compute the protection of vegetation by snow (Sect. 2.3.3).  ... 
doi:10.5194/gmd-10-4693-2017 fatcat:zhtwkuicd5ccbpcclwip6fp3fa

Page 74 of The Journal of Ecology Vol. 91, Issue 1 [page]

2003 The Journal of Ecology  
Assist- ance was received from Lucinda McWeeney and Donna Francis with sediment descriptions, and Julie Pallant with computer support. Thanks to P.D.  ...  Basin depth and size appear to be major factors in determining the timing of sediment changes during terrestrialization.  ... 

Biogeochemical factors contributing to enhanced carbon storage following afforestation of a semi-arid shrubland

J. M. Grünzweig, I. Gelfand, Y. Fried, D. Yakir
2007 Biogeosciences  
as about 60% of SOC under both land-use types were in mineral-associated fractions. 3) A short-term decomposition study indicated decreased decomposition of lower-quality litter and SOC in the forest,  ...  Our results suggest a role for increased N use efficiency, enhanced SOC protection and reduced decomposition rates in the large C sequestration potential following afforestation in semi-arid regions.  ...  Navon for assistance with the litter-decomposition study. We also acknowledge the technical help of E. Negreanu, P. Harel, O. Migdal, N. Kaufmann, N. Zehariah and S.  ... 
doi:10.5194/bg-4-891-2007 fatcat:2jtra3qefjhalgnskwpvdvqffe

Interannual variability in the peatland-atmosphere carbon dioxide exchange at an ombrotrophic bog

Peter M. Lafleur, Nigel T. Roulet, Jill L. Bubier, Steve Frolking, Tim R. Moore
2003 Global Biogeochemical Cycles  
Simulated decomposition and autotrophic respiration contributed about equal proportions to ER.  ...  Shrubs accounted for the greatest proportion of PSN (85%); moss PSN declined to near zero during the summer period due to surface drying.  ...  moss plus shrub (leaf, stem, and root) respiration, ''heterotrophic R'' equals peat decomposition lost as CO 2 , ''shrub NPP'' equals shrub photosynthesis minus shrub (leaf, stem, and root) respiration  ... 
doi:10.1029/2002gb001983 fatcat:vbfbq5csrrccnpgeou5dft6dqi

Modelling Holocene peatland dynamics with an individual-based dynamic vegetation model

Nitin Chaudhary, Paul A. Miller, Benjamin Smith
2016 Biogeosciences Discussions  
approach employs a dynamic multi-layer soil with representation of freeze-thaw processes and litter inputs from a dynamically-varying mixture of the main peatland plant functional types; mosses, dwarf shrubs  ...  the first half of the 21st century due to milder and wetter climate conditions, a longer growing season, and CO2 fertilization effect, turning into a carbon source after mid-century because of higher decomposition  ...  Here HSS is high deciduous shrubs, LSE is low evergreen shrubs and LSS is low 641 deciduous shrubs, Gr means graminoids and M is moss.  ... 
doi:10.5194/bg-2016-319 fatcat:6fgvchjzr5f27dtlbtzkm227ey
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