956 research outputs found
ErdĆszegĂ©lyek fajösszetĂ©telĂ©t Ă©s szerkezetĂ©t meghatĂĄrozĂł tĂ©nyezĆk
VizsgĂĄlatainkat
kĂ©t eltĂ©rĆ termĆhelyi viszonyok között kialakult e
rdĆtĂĄrsulĂĄs esetĂ©ben
az
erdĆĂĄllomĂĄny Ă©s a szomszĂ©dos nyĂlt terĂŒlet ĂĄtmeneti zĂłnĂĄjĂĄban vĂ©geztĂŒk. A Budai-hegysĂ©gben kĂ©t cseres-
kocsånytalan tölgyes
(
Quercetum petraeae-cerris
S
oĂł
1963)
erdĆĂĄllomĂĄny, illetve a szomszĂ©dos parlag
-
terĂŒletek hatĂĄrĂĄn talĂĄlhatĂł,
kĂŒlönbözĆ Ă©gtĂĄji kitettsĂ©gƱ (ĂK, ĂNY, DK, DNY) erdĆszegĂ©lyeket
vizsgĂĄltunk.
CsĂĄfordjĂĄnosfa hatĂĄrĂĄban egy sĂkvidĂ©ki ĂŒde tölgy-kĆris-szil ligeterdĆ (
Fraxino pannonicae-Ulmetum
S
oĂł
in
A
S
zĂłd
1935 corr. 1963), illetve a szomszĂ©dos dunĂĄntĂșli mocsĂĄrrĂ©t (
Deschampsietum caespitosae
)
hatĂĄrĂĄn ki
-
alakult, az elĆbbiekkel
megegyezĆ Ă©gtĂĄji kitettsĂ©gƱ erdĆszegĂ©lyeket
vizsgĂĄltuk.
CĂ©lunk volt annak megĂĄllapĂtĂĄsa, hogy van-e hatĂĄrozott kĂŒlönbsĂ©g az ĂĄtmeneti zĂłna egyes szerkezeti ele
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meinek (nyĂlt terĂŒlet, lĂĄgyszĂĄrĂș szegĂ©ly, cserjĂ©s szegĂ©ly, erdĆköpeny, erdĆbelsĆ) fajösszetĂ©tele között, az egyes
erdĆtĂĄrsulĂĄsok, illetve a kĂŒlönbözĆ Ă©gtĂĄji kitettsĂ©gƱ szegĂ©lyek esetĂ©ben.
EredmĂ©nyeink alapjĂĄn a cseres-kocsĂĄnytalan tölgyes Ă©s a tölgy-kĆris-szil ligeterdĆ ĂĄllomĂĄnyok szegĂ©lyei
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nek fajösszetĂ©tele teljes mĂ©rtĂ©kben eltĂ©r egymĂĄstĂłl. Az erdĆszegĂ©lyek fajösszetĂ©tele Ă©s szerkezete minden eset
-
ben az
Ă©gtĂĄji kitettsĂ©gtĆl fĂŒggĆen alakul
Flow correlated percolation during vascular network formation in tumors
A theoretical model based on the molecular interactions between a growing
tumor and a dynamically evolving blood vessel network describes the
transformation of the regular vasculature in normal tissues into a highly
inhomogeneous tumor specific capillary network. The emerging morphology,
characterized by the compartmentalization of the tumor into several regions
differing in vessel density, diameter and necrosis, is in accordance with
experimental data for human melanoma. Vessel collapse due to a combination of
severely reduced blood flow and solid stress exerted by the tumor, leads to a
correlated percolation process that is driven towards criticality by the
mechanism of hydrodynamic vessel stabilization.Comment: 4 pages, 3 figures (higher resolution at
http://www.uni-saarland.de/fak7/rieger/HOMEPAGE/flow.eps
Perturbation in Population of Pulse-Coupled Oscillators Leads to Emergence of Structure
A new synchronization model based on pulse-coupled oscillators is proposed. A population of coupled oscillators is represented as a cellular automaton. Each cell periodically enters a firing state. Firing of a cell is sensed by other cells in a neighborhood of radius R. As a result the sensing cell may change its firing rate. The interaction strength between a firing and a sensing cell decreases with the squared distance between the two cells. For most starting conditions waves of synchronized firing cells emerge. Simulations indicate that for certain parameter values the emergence of synchronization waves occurs only if there is dispersion in the intrinsic firing frequencies of the cells. Emergence of synchronization waves is an important feature of the model
Association Between Serum 25-Hydroxyvitamin D Concentration and Optic Chiasm Volume
International audienc
Evaluating alternative mowing regimes for conservation management of Central European mesic hay meadows: A field experiment
<p>Conservation status of hay meadows highly depends on their management. The main goal of this study was to assess the efficiency of different mowing regimes in maintenance of plant species richness and diversity of mesic hay meadows. The field experiment was carried out on a species rich, mesic hay meadow in Western Hungary. We evaluated the effects of four alternative types of management on the plant community after 7Â years of continuous treatment: (1) mowing twice a year, typical traditional management, (2) mowing once a year in May, most practised currently by local farmers, (3) mowing once a year in September, often proposed for conservation management and (4) abandonment of mowing. Traditional mowing resulted in significantly higher number and higher diversity of vascular plant species than other mowing regimes. Mowing twice a year was the only efficient way to control the spread of the invasive <i>Solidago gigantea,</i> and mowing in September was more successful in it than mowing in May. We conclude that the traditional mowing regime is the most suitable to maintain botanical diversity of mesic hay meadows; however, other regimes should also be considered if certain priority species are targeted by conservation.</p
Enclosing the behavior of a hybrid automaton up to and beyond a Zeno point
Even simple hybrid automata like the classic bouncing ball can exhibit Zeno behavior. The existence of this type of behavior has so far forced a large class of simulators to either ignore some events or risk looping indefinitely. This in turn forces modelers to either insert ad-hoc restrictions to circumvent Zeno behavior or to abandon hybrid automata. To address this problem, we take a fresh look at event detection and localization. A key insight that emerges from this investigation is that an enclosure for a given time interval can be valid independent of the occurrence of a given event. Such an event can then even occur an unbounded number of times. This insight makes it possible to handle some types of Zeno behavior. If the post-Zeno state is defined explicitly in the given model of the hybrid automaton, the computed enclosure covers the corresponding trajectory that starts from the Zeno point through a restarted evolution
Time evolution in the Morse potential using supersymmetry: dissociation of the NO molecule
We present an algebraic method for treating molecular vibrations in the Morse
potential perturbed by an external laser field. By the help of a complete and
normalizable basis we transform the Schr\"{o}dinger equation into a system of
coupled ordinary differential equations. We apply our method to calculate the
dissociation probability of the NO molecule excited by chirped laser pulses.
The dependence of the molecular dipole-moment on the interatomic separation is
determined by a quantum-chemical method, and the corresponding transition
dipole moments are given by approximate analytic expressions. These turn out to
be very small between neighboring stationary states around the vibrational
quantum number , therefore we propose to use additional pulses in order
to skip this trapping state, and to obtain a reasonable dissociation
probability.Comment: 4 pages, 3 figure
Neural effects of oxytocin and mimicry in frontotemporal dementia: A randomized crossover study
OBJECTIVE: To determine whether intranasal oxytocin, alone or in combination with instructed mimicry of facial expressions, would augment neural activity in patients with frontotemporal dementia (FTD) in brain regions associated with empathy, emotion processing, and the simulation network, as indexed by blood oxygen-level dependent (BOLD) signal during fMRI. METHODS: In a placebo-controlled, randomized crossover design, 28 patients with FTD received 72 IU intranasal oxytocin or placebo and then completed an fMRI facial expression mimicry task. RESULTS: Oxytocin alone and in combination with instructed mimicry increased activity in regions of the simulation network and in limbic regions associated with emotional expression processing. CONCLUSIONS: The findings demonstrate latent capacity to augment neural activity in affected limbic and other frontal and temporal regions during social cognition in patients with FTD, and support the promise and need for further investigation of these interventions as therapeutics in FTD. CLINICALTRIALSGOV IDENTIFIER: NCT01937013. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that a single dose of 72 IU intranasal oxytocin augments BOLD signal in patients with FTD during viewing of emotional facial expressions
Reconstruction of Trees from Jumbled and Weighted Subtrees
Let T be an edge-labeled graph, where the labels are from a finite alphabet Sigma. For a subtree U of T the Parikh vector of U is a vector of length |Sigma| which specifies the multiplicity of each label in U. We ask when T can be reconstructed from the multiset of Parikh vectors of all its subtrees, or all of its paths, or all of its maximal paths. We consider the analogous problems for weighted trees. We show how several well-known reconstruction problems on labeled strings, weighted strings and point sets on a line can be included in this framework. We present reconstruction algorithms and non-reconstructibility results, and extend the polynomial method, previously applied to jumbled strings [Acharya et al., SIAM J. on Discr. Math, 2015] and weighted strings [Bansal et al., CPM 2004], to deal with general trees and special tree classes
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